* GB785403 (A)

Description: GB785403 (A) ? 1957-10-30

Improvements in or relating to adhesive compositions for splicing flexiblesheet material

Description of GB785403 (A)

PATENT SPECIFICATION Inventors: JEROME D GROVE and PHILI' V PALMQUIST 785403 Date of Application and filing Complete Specification Nov 25, 1955. No 33924/55. Complete Specification Published Oct 30, 1957. Index at acceptance: -Classes 2 ( 5), R 1 (C 6: C 8: C 10: C 12: PI: P 2: PS), R 20 (C 6: C 8: C 10: C 12: P); 2 ( 6), P 2 A, P 2 C( 5: 8 B: 13 A: 20 A: 2 OC: 20 DI: 20 D 3), P 2 (DIA: K 8: T 2 A); and 42 ( 1), K. International Classification: -CO 8 g C 09 j. COMPLETE SPECIFICATION Improvements in or relating to Adhesive Compositions for Splicing Flexible Sheet Material We, MINNESOTA MINING AND MANUFACTURING COMPANY, a corporation organised under the laws of the State of Delaware, United States of America, of 900, Fauquier Avenue, Saint Paul 6, Minnesota, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to splicing, or joining flexible sheet material The invention aims to provide a new type of heat-resistant splice having high tensile strength, a convenient and rapid method for making such a splice, and a novel temporarily thermoplastic splicing adhesive in dry film form for use in connection therewith. The invention is particularly useful for splicing adjacent sections of heavy coated flexible sheet material, e g, reflex-reflective sheet material having a fabric or film backing and a heavy dense surface coating of adherently bonded tiny glass sphericles, or other particulate-coated sheet material, during drying or heat-curing of the

sheet in the form of suspended loops. The weight of particulate-coated sheets makes a strong splice essential Further, the high temperature of curing ovens requires that the splice be heat-resistant and non-thermoplastic Another requirement is that the splice must be easily and rapidly made. In large-scale commercial oven-curing of various types of treated or coated sheet materials, the curing operation is carried out while the material is suspended in the oven in long vertical loops Successive strips are spliced for ease in coating and suspending the material, and in order that the loops may later be economically taken down and wound up in roll form Any break in the coating and lPrice 3 s 6 d l racking operations results in loss of production and is to be avoided. Adhesives in solution form e g, solutions of various resins in organic solvents, have previously been employed for splicing operations such as above described Removal of solvent is necessary in order to obtain a strong bond, and the operation is therefore undesirably lengthy A further disadvantage is that in many cases the solvent causes softening or wrinkding of the sheet material to which the adhesive solution is applied. The use of pre-formed films for joining various sheet materials has previously been suggested Films of cellulose nitrate, dipped or briefly soaked in acetone, have been suggested as an improvement over cellulose nitrate solutions in joining fabrics Phenolic resins supported on thin paper have replaced solution type adhesives in the making of certain varieties of plywood Thermoplastic adhesives such as cellulose nitrate however, soften when heated, and such splices come apart in the curing ovens Phenolic resins, when heated, slowly form a strong but brittle and easily broken bond Splices made with these resins fail when the spliced area is pulled across rack sticks or is jerked from the rack in the oven-curing of the spliced sheet material. According to the invention, a temporarily thermoplastic, rapidly heat-curing adhesive composition in dry film form comprises a rubbery butadiene-acrylonitrile copolymer, an oil-soluble heat-advancing phenol-aldehyde resin, and a monomeric methylene-quinoneliberating di-halomethyl alkyl phenol vulcanizing agent having the halomethyl groups ortho to the phenol hydroxyl. The novel dry film adhesive of the invention contains and requires no solvents or other ingredients which must later be removed and which might have an undesirable effect on the 785,403 sheet material It forms an effective adhesive bond when hot-pressed The film rapidly heat-cures to a firm, tough, non-thermoplastic state when heated above a critical temperature. Splices made in heavy coated sheet material having a non-porous backing are extremely strong even at elevated temperatures, being

capable of supporting the weight of several yards of the coated sheet when passing through an oven at temperatures up to at least F No hitherto known adhesive has been found capable of producing such results. The following examples gives in some detail the preparation of a splicing film embodying the invention:EXAMPLE I Parts by Constituents Weight Butadiene acrylonitrile rubbery copolymer 100 Zinc oxide 10 Oil-soluble heat-advancing 100 % phenol-aldehyde resin 50 Hard, neutral thermoplastic resin 50 Salicylic acid (" Retarder W ") (optional) 15 Acetone 410 2,6 dibromomethyl 4 methylphenol 3 The rubbery copolymer was first softened on a rubber mill, and the zinc oxide incorporated The resulting mill batch, together with the remaining ingredients, the retarder being optional, was dissolved (or finely dispersed) in the acetone, using a simple paddle type stirrer, to form a homogeneous blend To this blend was then added the 2,6-di-bromoe methyl-4 methylphenol The resulting fluid composition was coated in a thin uniform layer on a temporary carrier sheet, such as polyethylene-coated paper, and dried at room temperature Before use, the dried film was stripped from the carrier sheet It was found to be self-supporting, normally stable and long-aging, temporarily thermoplastic and heat-activatible, rapidly heat-curing and eminently suitable for making splices in accordance with this invention. The film was about 0 003 inch thick, and in general it is preferred to employ films within the range of 0 002 to 0 008 inch thickness Thinner films sometimes do not completely contact all surfaces of the areas to be spliced Thicker films either undesirably increased the thickness of the splice or result in flowing of a portion of the composition beyond the edges of the spliced areas The thickness of the film should be regulated to some extent in accordance with the thickness of the material to be spliced, the thicker sheet material requiring thicker adhesive films. Thicker adhesive films, as well as sheet materials having thicker and heavier backings, frequently require somewhat longer periods of pre-heating than do thinner materials. The particular rubbery copolymer employed in the composition of Example I was a copolymer of 70 parts of butadiene and 30 parts of acrylonitrile Other proportions may also be successfully employed A considerable per 70 centage of acrylonitrile or equivalent in making the copolymer appears to be essential, but too high a proportion of acrylonitrile produces a stiff boardy polymer which is hard to mill and to dissolve In general, the range 75 of 20 to 40 % of acrylonitrile is preferred; within this range, the copolymers are rubbery and provide excellent properties in the adhesive film Small

amounts of other copolymerizable monomers may be polymerized with 80 the butadiene and acrylonitrile, or may be substituted for a portion of a principal monomer; for example, isopreme may be incorporated. Phenolic resins prepared by the alkali-catalyzed condensation of about 1 2 to 1 6 mols 85 of an aldehyde such as formaldehyde with one mol of a substituted phenol such as a parasubstituted alkyl or aryl phenol, e g, paratertiary-amyl phenol, have given excellent results in these compositions This class of 90 resins is well-known to the art as oil-soluble, heat-advancing or heat-reactive, 100 % phenolaldehyde resins, and is represented by many commercially available resins. The hard, neutral thermoplastic resin used 95 in Example I was the glycerol ester of a gasoline insoluble aromatic hydrocarbon soluble resinous extract of pine wood It represents a preferred neutral modifying resin for the blend of rubbery polymer and reactive 100 phenolic resin It, or another equivalent hard, neutral, thermoplastic resin imrroves the heatbonding properties of the film, and also improves the firmness of the bond or splice obtainable with the film This relatively 105 inexpensive resinous component also reduces the over-all raw materials cost of the film. However, this resinous compound may be replaced by an acetone-soluble phenolic resin. Plasticizers, e g, dibutyl phthalate, have 110 been incorporated in limited amounts into these film-forming compositions where greater flexibility was desired. Compounds such as 2,6-di-bromomethylf 4methylphenol have been shown to act as 115 vulcanizing agents for crude rubber, the reaction being due to the formation of a reactive methylene quinone on heating of the composition The quinone then reacts with active hydrogen atoms of the rubber molecule 120 to form an addition compound The reaction is described in the thesis "De vulcanisatie van rubber met phenol-formaldehyd-derivaten " of S Van Der Meer, originally published in Delft, 1943; see also Chemical Abstracts, 125 volume 39, page 3961. The Van Der Meer paper describes a larger number of rhenol-alcohlols and their halogen derivatives Reich are decomuosable to provide methylene quirone and are applicable to the 130 785,403 vulcanization of rubber While the compounds there described are found to have value in film compositions according to the invention, it has been found, contrary to the implications of the Van Der Meer thesis, that the halogenated materials are much superior to the hydroxy compounds for the purposes of the invention Thus the phenol-alcohols, e g, 2,6-di-hydroxymethyl-4-methylphenol, require extreme caution in their use in such films, since they tend to cause reduced stability of the dried film and to result in inferior adhesion to the backing of the flexible sheet material Of the halogenated compounds, the chloro

derivatives, e g, 2,6-di-chloromethyl-4methylphenol, appear unnecessarily reactive and tend to cause scorching of the film When the brominated compounds, and particularly 2,6-di-bromomethyl 4 methylphenol, are employed as organic heat-curing agents, these adhesive film products are found to be readily manufactured, normally stable, and rapidly activated and vulcanized. The specific compound 2,6-di-bromomethyl4-methylphenol melts at 114 to 1150 C It has been found that vulcanization of the film products of this invention proceeds with extreme rapidity at temperatures above the melting point of the substituted phenol and particularly in the neighbourhood of 300 to 3750 C Even though many commonly employed non-melting sheet materials such as paper, cloth, cellulosic or resinous films, etc, are rather rapidly deteriorated at temperatures of that order, the rapidity of vulcanization of our novel splicing film is such that the full strength of these sheet materials is maintained during the splicing operation. Three methods of forming splices between strips of flexible sheet material in accordance with the present invention are indicated in the accompanying drawing, in which Figure 1 represents a vertical cross section of an overlap splice, Figure 2 represents a vertical cross section of a butt splice, and Figure 3 is a variation of the splice in Figure 2. The coated sheet material of Figure 1 consists of a backing member B and a heavy coating C applied to one side thereof, the coating having a rough outer surface of particulate material In order to make a strong overlap splice with such a sheet, it is necessary first to remove the coating from one of the areas to be spliced, e g by scraping or abrading. The coating may also be removed from the corresponding area of the other sheet, particularly if it is desired to produce a splice which is no thicker than the original unspliced sheet. For the same reason, where the backing is relatively thick, the edges of the backing may be skived or feather-edged before splicing A section of dry adhesive film A, prepared in accordance with Example I, is then placed between the two edge portions, as indicated in Figure 1, and the assembly placed briefly under heat and pressure to form a tough, strong, flexible, adherent and heat-resistant splice. Figure 2 represents an alternative method of forming a splice, using the dry adhesive film of the invention The pre-formed dried adhesive film A is supported on a reinforcing layer R of fabric or the like, and is pressed against the back surfaces of two abutting sections of flexible sheet material F which are to be spliced together No preliminary scraping of either section is required, although in some cases it may be found desirable to abrade or roughen the otherwise

glazed surface of the sheet material in order to provide improved adhesion. Where the splice is temporary only, and the spliced portion is to be removed later, it is sometimes more convenient to overlap the edge portions and to attach the adhesivecoated reinforcing layer R to the back surface of both portions along the edge of the under portion, as illustrated in Figure 3 Such a splice may be pulled across rack sticks and around rollers in one direction without difficulty, even though when pulled in the other direction the overlapped upper portion may loosen and cause trouble The splice is particularly effective as a means of rapidly yet effectively joining strips of sheet material temporarily, as for passage through an oven, where the spliced area is later to be discarded. The following examples indicate suitable methods for preparing splices according to the invention: EXAMPLE II Cloth strips impregnated with phenolic resin and carrying a surface coating of dense, heavy inorganic particulate material bonded to the impregnated cloth with a phenolic resin binder 105 were spliced together by first abrading the surface coating from about a -4 inch width area along the adjoining edges cf Fig 1 of drawing, fitting a section of the adhesive splicing film of Example I over the thus exposed back 110 ing of the strip, lapping the reverse surface of the other prepared edge area over the filmcovered prepared edge area, and pressing and heating the composite structure A preliminary heating period of 10 seconds at 200 pounds 115 per square inch, with the press platens at 355 to 3850 F, warmed the assembly and softened the film Pressure was then increased to 3000 pounds per square inch for 15 seconds to complete the operation The resulting splice was 120 as strong as the original coated sheet material, both in tensile and in flexing tests and at elevated temperatures of the order of 200 to 2500 F as well as at room temepratures. The preliminary removal of the surface 125 coating from the edge portion of the sheet renders that portion susceptible of being adhesively bonded While the adhesive film might adhere to the coating, the latter would in many instances form a weak link in the 130 785,403 assembly and unless first removed would cause the splice to fail With some types of coatings having sufficient strength and flexibility, suitable surface characteristics, and not too great thickness, and where uniform thickness across the splice area is not essential, this preliminary treatment of the edge area is unnecessary For example, cloth webs lightly sized with ethyl celulose may be spliced together with an adhesive film according to the invention without any preliminary treatment, to form a strong, tough, flexible and non-thermoplastic joint or splice.

EXAMPLE m To a strong, tough, dense, untreated paper carrier web was applied in order a film-forming resin layer, a reflective layer, a resinous reactive binder layer, and a surface layer of glass sphericles, to produce a reflex-reflective sheet material on a removable paper carrier. Heat-curing of the resinous binder layer was facilitated by splicing together strips of this sheet material to form a continuous web for passage through a curing oven The spices were assembled as shown in Figure 3 of the drawing, using a cloth reinforcing layer and a separate adhesive film layer, the latter being the dried film of Example I The splice was completed by pressing the assembly with a hot flat-iron and with considerable pressure for about one-half minute per yard of splice. The temperature of the film was then raised at least to about 300 F. EXAMPLE IV Abutting sections of a reflex-reflective sphericle-surfaced flexible sheet material having an exposed aluminium foil backing were spliced together as in Figure 2 of the drawing, using the adhesive film of Example I in conjunction with a coextensive area of fabric, and heating and pressing with a hot flat-iron as just described The film exhibited strong adhesion to the metal surface Brief heating with the flat-iron was sufficient to promote firm adhesive bonding and to cause curing of the film to a non-thermoplastic, highly heat-resistant state The splice showed no signs of failure when stressed to the breaking point of the sheet material at oven temperatures. For greater convenience the pre-formed film may preliminarily be ligrhtlv heat-bonded to the fabric or other reinforcing sheet, so that only one section of sheet material need be handled An equivalent structure 'is more simply prepared by coating the adhesive solution of Example I directly on cloth, paper, " Cellophane " (Registered Trade Marl;) metal foil or other reinforcing sheet and drying at room temperature to a smooth surface The resulting coated sheet possesses equally as good splicing characteristics as the combination o& separate fabric and film where splices of the type illustrated in Figures 2 and 3 are concerned. Splices made as herein described with the 65 films of this invention are strong, flexible and uniform, and retain their excellent properties under conditions of oven-curing Thev make possible the handling of coated sheet material such as beaded fabric or film, as well as various 70 other sheeted products, in the form of continuous strips during coating, curing, and forming into rolls No splices or splicing adhesive previously known have been fully effective for such application 75 Whilst it is preferred to employ film materials made in

accordance with the specific formula and procedure of Example I, it is found that splices made with film materials of various modified formulas also show desir 80 able improvement over known splices Thus the proportions of the specific ingredients of Example I, or of equivalent materials such as have been described, may be quite widely varied while still retaining the desired flexi 85 bility, adhesion high strength, solvent resistance, absence of heat-softening, rapiditv of cure and other properties of the product. Where reference is made to the step of assembling the sections of the sheet material in 90 reinforcing relationship, it will be understood that both the lapping of the sections upon each other (with an intercalated adhesive film having both surfaces available for adhesion to the said sections, as illustrated in Figure I) 95 and also the lapping of the sections over an external reinforcing member (with the intercalated adhesive film lying between the said reinforcing member and each of said sections, as in Figures 2 and 3) are to be included 100

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* GB785404 (A)

Description: GB785404 (A) ? 1957-10-30

Improvements in laminated springs

Description of GB785404 (A)

A high quality text as facsimile in your desired language may be available amongst the following family members:

FR1138159 (A) FR1138159 (A) less Translate this text into Tooltip

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The EPO does not accept any responsibility for the accuracy of data and information originating from other authorities than the EPO; in particular, the EPO does not guarantee that they are complete, up-to-date or fit for specific purposes.

PATENT SPECIFICATION Date of Application and filing Complete Specification: Dec 6, 1955. Application made in Germany on Dec 27, 1954. Complete Specification Published: Oct 30 1957. Index at acceptance:-Class 108 ( 3), 55 H 4. International Classification:-FO 6 f. COMPLETE SPECIFICATION Improvements in Laminated Springs We, MASCHINENFAB Ri K AUGSBURG-NURNBERG A G, of Nurnberg, Germany, a German Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a laminated spring bank for motor vehicles, the ends of which are supported with rolling contact on plates of the chassis frame. The known rolling contact springing arrangements have the disadvantage, that the occurring pull and push forces have to be taken up and transmitted by auxiliary elements, such as link members, straps, push rods and the like. The present invention consists in a laminated spring bank for motor vehicles, in which each spring leaf is in contact with the shorter of the two adjacent leaves along the whole length of said shorter adjacent leaf, and in which a spring leaf disposed approximately in the centre of the otherwise regularly stepped spring bank has one end freely projecting from the spring bank, said end being bent to form a pivot eye which may be surrounded with clearance by an eye of an adjacent spring leaf and which is pivoted to the chassis, the top leaf of the spring bank bearing at both ends with free rolling contact against rolling surfaces of the chassis. At the same time, for preventing the spring end from losing contact with its plate, on the application of the brakes or on starting suddenly, these spring leaves of the bank of springs are so sprung that in the assembled state they press the bearing spring end against the rolling plate. For obtaining good silencing, according to a further feature of the

invention the rolling plates for the laminated spring are insulated with respect to the spring bracket by interposed members of a kind known per se For further silencing and avoiding lubrication of lPrice 3/6 l the spring eye of the extended spring leaves may embrace an elastic member of a kind known per se, in which the spring bolt rests. In the accompanying drawing a constructional example of the invention is illustrated 50 diagrammatically. The bank of springs 1, the middle part of which is rigidly connected to a vehicle axle A in the usual manner, bears with the outer ends of its spring leaves on rolling plates 2 which 55 together with interposed silencing discs 4, for instance of rubber, synthetic material or the like, are fixed in each case to a spring bracket 3 Each spring bracket is fixed by screws, rivets or other connecting means to the frame 60 (not shown) of the motor vehicle undercarriage The spring leaves 7 of the bank of springs 1 are sprung in such a manner that, in the assembled state, they press the ends of the bank of springs, lying above them, against 65 the adjacent rolling plate 2 By this means a lifting of the spring ends from their support is prevented, more particularly on the brakes being applied or the motor vehicle being started suddenly 70 In order to be able to transmit and pass on the occurring driving and braking forces in a natural manner, from about the middle of the bank of springs 1 two or more spring leaves 7, adjacent to one another, are extended to one 75 side beyond their similarly directed ends. The spring leaves lengthened in this manner may be formed at their ends into substantially concentric eyes 8 embracing one another, with which the spring can be flexibly fixed on 80 spring bolts 6 mounted on an extension 9 of the spring bracket 2 or the like The supporting of the spring eyes 8 on the spring bolts 6 holding them is preferably effected with the interposition of an elastic bush 5 of 85 rubber, synthetic material or the like, whereby an additional excellent silencing of the spring suspension is obtained and, at the same time, the hitherto required necessity of lubricating the spring support becomes superfluous 90 785,404 No 34929/55. 785,404

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* GB785405 (A)

Description: GB785405 (A) ? 1957-10-30

Improvements relating to gas-concentration meters

Description of GB785405 (A)

COMPLETE SPECIFICATION Improvements relating to Gas-concentration Meters We, ETABLISSEMENTS JEAN TURCK, a Body Corporate organised and existing under the Laws of France, of 10, rue Leibnitz, Paris, France, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to gas-concentration meters of the type which utilise the characteristic properties of the infra-red part of the spectrum of the gases considered. All the meters of this type at present in use operate on the total infra-red flux. A meter in accordance with the present invention comprises the following special features: (1) The infra-red energy used occupies a very small field of the spectrum, characteristic of the zone of absorption of the gas to be measured. It is thus necessary to use a dispersive system, the separating power of which depends on the sensitivity of the detector employed to the utilised portion of the band of absorption of said gas. (2) The meter is strictly selective, that is to say, it is possible to measure the concentration of the gaseous compounds whose bands of absorption are partly or wholly superimposed. It will suffice that one line infra-red rotation of the gas to be measured is separated from the other lines of rotation belonging to the other compound, which can always be effected, as shown by infra-red technique, if the:separating power of the dispersive system employed is adequate. (3) Use is made of the zero method, that is to say an absolute stability of emission of the infra-red source is not strictly

indispensable, and this is also true in respect of the stability of the electronic amplifier system. (4) The measurement of the concentration of the gaseous compound is made by bringing a measuring instrument back to zero by acting, by means of an attenuator, on the intensity of the infra-red beam that has not passed through the gas. (5) The meter, the essential purpose of which is to determine the concentration by volume of a gas or gaseous compound, may in addition be associated with a system which acts on shutters for example in order to vary the concentration of the gas and to bring it to a predetermined value. A meter in accordance with the invention is described below by way of example and without any implied limitation, and is illustrated in Figs. 1 and 2 of the accompanying drawings which show, as to Fig. 1, a diagram of the mono-chromatising device, and as to Fig. 2 a diagram of the measuring means proper; the two are actually joined to each other along the lines X-X. The meter comprises essentially three distinct parts : - (a) A mono-chromatising device; (b) An infra-red absorption measuring device; and (c) An electronic measuring means. (a) The mono-chromatising device in accordance with the invention has a resolving power sufficient to separate a narrow spectral field in such a manner as to obtain a large and selective absorption of the gas to be measured. This device uses a system to disperse the infra-red radiation and the position of this system with respect to the incident beam enables a suitable spectral zone to be obtained. The field of absorption of either the fundamental bands or the harmonic bands may be utilised, the choice between these being especially determined by the type of detector used. Thus, for example, for the measuring of water vapour, there is used with advantage a spectral zone in the vicinity of 2.8 IA for ammonia, and for methane zones in the vicinity of 1.9 and 1.7 ii, respectively. It is quite clear that any other specific zone of the gas may be utilised. This mono-chromatising device should permit, for example, of the separation of a spectral field of 10 cell. It has been designed as simply as possible and should have aberrations which are compatible with its separating power. It comprises an infra-red source S, which may for example, be a Nernst filament, a suitable resistance or an incandescent lamp with a glass bulb if the mono-chromatising device is to unction up to 3 IL,

which is the limit of transparence of the glass. By means of a concave mirror m, an image of the source is formed at the entry slot F of the mono-chromatising device, and a system of two spherical mirrors Ml and Mo working in the vicinity of their principal axes, associated with a plane diffraction system R, for example, enables an infra-red spectrum to be obtained. Rotation of the diffraction system enables the spectrum to be passed through the outlet slot Fl. Any other dispersive system may obviously be employed, provided that it complies with the conditions previously indicated. In order to make the meter universal, the position of the diffraction system is provided with reference marks. Each mark corresponds to a spectral zone which is characteristic of the absorption of the gas to be measured. The whole of the optical system of the mono-chromatising device is placed inside a mechanically stable chamber, and no other condition is required for its correct operation. (b) The infra-red absorption measuring device comprises two given paths for beams of infra-red light starting from the outlet slot F1 of the mono-chromatising device. The first path includes the chamber C containing the gas the concentration of which is to be measured, while the second may include a chamber (not shown) filled with an inert gas which is transparent to infra-red radiation (N2s 0,, etc.). These two light paths are formed by means of a simple device starting from a single parallel beam of light obtained by means of a lens L1 placed in front of the outlet slot of the mono-chromatising device. A system of plane mirrors Me, M4, M5, M6 andalensL2 enablethe two beams to be again focused in such a manner that the two images of the two halves of the slot are superimposed on a detector. This coincidence of the two images is necessary if it is desired to eliminate the variations in sensitivity of the different points of the detector employed. The length of the chamber containing the gas is a function of the nature of the gas, of the spectral zone utilised, that is to say of the coefficient of absorption of this gas, and of the accuracy which is to be demanded. In order to measure with an accuracy of 10- by volume of gases such as H O, NH,, CH,, CHC, etc., a length of 100 cm. is amply sufficient. For such a length, the accuracy with CO. would be much greater. This accuracy depends obviously on the stability and on the ratio of signal I background-noise of the amplifier used. The sensitivity of the meter may be increased by using a multiple-reflection chamber (with paths which may amount to 100 metres instead of a chamber of one

metre in length. The light corresponding to these two optical paths is modulated in phase opposition by means of a disc M pierced with holes, the width of which is equal to half the utilisable height of the outlet slot of the mono-chromatising device. On the path which does not include the absorption chamber, there is arranged a light attenuator A (a grid aith variable mesh, a polanser-analyser, etc.) which enables the light intensities of the two paths to be made equal when the chamher does not contain any absorbent substance. This attenuator will in fact serve as a device for measuring and determining the concentration of the absorbing gas: it should be set to the zero point of its graduation when the chamber does not contain the absorbent gas. This operation is effected by using an auxiliary attenuator which should remain fixed when the meter has once been adjusted. The measuring attenuator is graduated directly in concentration. This graduation is only valid for one single gas measured. However, a system of diagrams will enable other gases to be measured. (c) The electronic measuring means, shown at D, co-operates with aforesaid detector, an dcomprises a selective amplifier. The rays of light following the two optical paths coincide and fall on the same portion of the detector, which may be for example a photo-resistant cell or any other infra-red detector; there is however an advantage to be gained from the use of a non-cooled lead sulphide cell whenever this is possible. If the two light fluxes are equal, the light intensity falling on the cell is constant by reason of the modulation in phase opposition. If the intensity of the light flux passing through the chamber is reduced as a result of the phenomenon of absorption, the detector receives a modulated flux of light, the potential at the output of the detector is no longer constant, and this potential is amplified by means of the electronic amplifier which is tuned to the modulation frequency in such a manner as to increase the signal/background-noise ratio to the maximum. An amplification of the order of 1,000 is generally amply sufficient, the passband of the amplifier being of the order of onetwentieth of the modulation frequency. The amplified potential is rectified and passed to any suitable indicator in accord ance with the requirements of the user. In the case in which the meter functions as a zero device, the attenuator is adjusted so as to make the fluxes equal, the measuring indicator returns to the zero mark and the concentration of the gas is read-off directly by means of diagrams. What we claim is:- 1. An infra-red gas-concentration meter comprising: (a) a mono-chromatising device consisting of an infra-red source, a concave

mirror, a slot at which is formed the image of said source, two spherical mirrors associated with a diffraction system for obtaining an infra-red spectrum, said diffraction system being rotatably mounted, and an outlet slot; (b) an infra-red absorption measuring device arranged so as to form, starting from a single beam passing out of said outlet slot, two paths for beams of infra-red light obtained by a rotating disc pierced with holes the width of which is equal to one-half of the usable height of the outlet slot of the monochromatising device, one of said paths passing through a chamber containing the gas the concentration of which is to be measured, the other of said paths passing through a calibrated adjustable attenuator, and an optical device to focus said two paths in such such a manner that the two images of the two halves of said slot are superimposed on a detector; and (c) an electronic measuring means co-operating with said detector comprising a selective amplifier tuned at the same frequency as the rotation of said disc, and an indicator for said amplifier. 2. A infra-red gas-concentration meter as claimed in Claim 1, in which one of said. paths is formed by a double system of two plane parallel mirrors. 3. An infra-red gas-concentration meter as claimed in Claim 1 or 2, in which said attenuator is graduated in concentration and is adjusted to zero when it accomplishes the equalisation of the two intensities of the light following the two paths when the chamber does not contain any absorbing substance. 4. An infra-red gas-concentration meter as claimed in any preceding claim, in which the voltage amplified by said electronic apparatus is utilised to vary, through servo-con- trol means, the concentration of a gas the concentration of a sample of which is being measured.

* GB785406 (A)

Description: GB785406 (A) ? 1957-10-30

Emulsion paint vehicles

Description of GB785406 (A)

A high quality text as facsimile in your desired language may be available

amongst the following family members:

BE542261 (A) DE1108357 (B) FR1137676 (A) NL93402 (C) US2833737 (A) BE542261 (A) DE1108357 (B) FR1137676 (A) NL93402 (C) US2833737 (A) less Translate this text into Tooltip

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PATENT SPECIFICATION 7859406 Date of Application and filing Complete Specification: Dec 12, 1955. No 35664/55. Application made in United States of America on Dec 30, 1954 '. Complete Specification Published: Oct 30, 1957. Index at acoeptanoe:-Class 2 ( 6), P 4 A, P 4 C(ii:8:12 X 13 I 13 f: f:14 E:sf A:1 f E:17 ig.2 a B:20 C:2001:20 D 2), P 4 D( 3 81:8), P 4 X 9, P 4 P Ih EW( 1:5), P 4 P 2 (A 1:A 4:A 5: B:C:X), P 4 P( O W:CA), P 9 At P 90 ( 4 A:3 B: 112 X:A: 13 C:14 A 0:s 4 143:56 "@ 160 17 18:201 B:20 C:2001: 20102), P 9 D( 1 B:), 1 P 9 E((i:s 9), SP 1 PE( 1 5)3, P 9 P 2 (A 1 I:A 4: A 5:BC:X), P 9 P( 4 W:6 A). International Ciassification:-C 00 f. COMPLETE SPECIFICATION Emulsion Paint Vehicles We, W R GRACE & Co, a corporation organised and existing under the laws of the State of Connecticut, United States of America, and having a place of business at 62, Whittemore Avenue, Cambridge, Massachusetts, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- As vehicles for water based paints, polyvinyl acetate emulsions have been found to have many advantages They are obtainable at a reasonable cost they have a good emulsion stability which is unaffected by acidic materials or polyvalent ions, they have excellent film forming properties, light colour, a good colour stability, a good stability to

oxygen and ultra-violet light resulting in good resistance to exterior exposure, selfpriming properties on porous surfaces, an excellent grease and oil resistance, a good adhesion to most substrates, and a good moisture vapour permeability which tends to eliminate blistering and peeling. In order to be useful as vehicles for water based paints, polyvinyl acetate emulsions must be plasticised The plasticiser confers the necessary flexibility and extensibility to what would otherwise be a hard and brittle film Probably because of its softening effect on the resin particles the plasticiser in addition aids in the process of film formation. There is usually employed as the plasticiser a phthalic ester, such as dibutyl phthalate, in amount of from 5 to 15 1, based on the resin content of the:mulsion usually being necessary. The fact that a plasticiser must be used as a part of the vehicle in a paint based upon a polyvinyl acetate emulsion is both an advantage and a serious disadvantage On the one hand a paint formulator, by using different plasticisers, i ary F ounts, can, to some lPrice extent tailor his vehicle to suit his particular requirements However, the resulting film forming material is a physical mixture of two materials, i e, the polyvinyl acetate resin and the plasticiser Like all such mix 50 tures, this mixture is separable by such physical processes as evaporation, migration or leaching and this separability is an important potential source of trouble where the durability and weather resistance of thin 55 films is involved The separation and loss of plasticiser over a period of time and of exposure can seriously embrittle the film In addition, the use of an organic liquid plasticiser as part of the vehicle in an emulsion 60 paint sometimes causes colour difficulties where organic pigments are used owing to the possibility of flushing between the water and plasticiser phases. Polyvinyl acetate has a further failing in 65 common with many other water insoluble polymers, in that films and coatings formed from emulsions of polyvinyl acetate under normal drying conditions are quite water susceptible The apparent reason for this 70 water susceptibility is that the water susceptible materials required in the production of a stable emulsion of the polymer persist in the dried film, and tend to make that dried film re-emulsifiable 75 It has previously been proposed that the loss of plasticiser could be prevented were the vinyl acetate to be copolymerised with certain co-polymerisable plasticisers The most useful of such plasticisers are certain 2 G aliphiatic esters of maleic or fumaric acid. It has likewise previously been proposed that the water susceptibility of films formed from a polyvinyl acetate emulsion could be reduced by the addition to the emulsion of os hexylene glycol or other glycol or

glycol derivative which when incorporated in an ordinary polyvinyl acetate emulsion has the effect of rendering films produced therefrom, less water susceptible than are films pro 90 785,406 duced from the ordinary polyvinyl acetate emulsion itself. Compared with copolymers formed by copolymerising the same monomers in other proportions, the said copolymer is found to exhibit, when used in an emulsion paint vehicle containing a glycol stabiliser, certain unexpected advantages which will be referred to in detail hereinafter. In accordance with the present invention there is provided an emulsion paint vehicle comprising water having dispersed therein a copolymer formed by copolymerising from 82-1 to 67 parts by weight of vinyl acetate with from 17-f to 321 parts by weight of a co-monomer consisting of at least one diester of maleic or fumaric acid and a straight or branched chain saturated aliphatic monohydric alcohol having from 2 to 8 carbon atoms in the molecule, and also having dispersed therein from 5 to 17 parts per 100 parts by weight of said copolymer, of hexylene glycol, 3-chloro-1, 2-propanediol, 2 (beta butoxy ethoxy) ethanol, 2-butoxy-ethanol acetate or di-propylene glycol. The glycol type compounds just listed are herein referred to for brevity as glycolstabilisers and that term is to be understood to include only the listed compounds. There is also provided a water based paint which comprises a pigment and the emulsion paint vehicle There is also provided a cementitious coating material which comprises a hydraulic cement and the emulsion paint vehicle. Further in accordance with the present invention there is provided a method of preparing an emulsion paint vehicle which comprises forming a copolymer by copolymerising, while dispersed in water, from 821 to 67,1 parts by weight of vinyl acetate with from 171 to 321 parts by weight of a comonomer consisting of at least one diester of maleic or fumaric acid and a straight or branched chain saturated aliphatic monohydric alcohol having from 2 to 8 carbon atoms in the molecule and before, during or after the copolymerisation dispersing in the water from 5 to 17 parts by weight, per 100 parts by weight of the copolymer, of a glycol-stabiliser as hereinbefore defined. Co-polymerisation is preferably effected in the presence of a peroxygen catalyst (e g, an alkali metal or ammonium persulphate or hydrogen peroxide) in an amount sufficient to contain from 0 01 to 1 O of available oxygen based on the total weight of the vinyl acetate and the co-monomer. Particularly where the co-monomer employed in forming the copolymer contains alcohol residues containing more than 4 carbon atoms, the said residues are preferably of the branched-chain type The comonomer

may for example consist of at least one di-ester of maleic or fumaric acid and ethanol, a butanol, a propanol, 1 4-dimethyl1-butanol, a methyl pentanol, or 2-ethyl-lhexanol preferably the co-monomer consists of di-butyl maleate and/or di-butyl 70 fumarate As the glycol-stabiliser there is preferably employed hexylene glycol With the glycol-stabiliser employed in an amount of from 5 to 17 parts by weight per 100 parts by weight of the copolymer, as required by 75 the present invention, the vehicle and surface coating compositions compounded therefrom are converted to dry films in an acceptable period If less than 5 parts by weight were employed, the effect of the 80 glycol-stabiliser would be too small to be significant and if more than 17 parts by weight were employed the drying time would be excessive and the films would remain tacky for an extended period 85 Films produced from the emulsion paint vehicles provided by the invention either alone or in admixture with pigments and other emulsion paint additives are found not only to possess a permanent flexibility and go a remarkably low water susceptibility but also in most cases to have a stability under conditions of wet abrasion in the presence of soap solutions, which is outstandingly higher than is the case with films as usually 95 obtained from polyvinyl acetate based paints In the preferred case, where the comonomer consists of di-butyl maleate and/ or di-butyl fumarate, optimum results are obtained with a copolymer produced from 100 about 77 parts by weight of vinyl acetate and about 23 parts by weight of the comonomer As hexylene glycol is the preferred glycol-stabiliser, the preferred emulsion paint vehicle provided by the present 105 invention accordingly comprises water having dispersed therein a copolymer formed from about 77 parts by weight of vinyl acetate and about 23 parts by weight of dibutyl maleate, or of di-butyl fumarate or of 110 a mixture of di-butyl maleate and di-butyl fumarate and also having dispersed therein from 5 to 17 parts by weight, per 100 parts by weight of the conolyiner, of hexylene glycol 115 That a high wet abrasion resistance is obtained with the amount of co-monomer within the limits hereinbefore given is surprising since one would expect that as the co-monomer content of such a copolymer is 120 increased from zero, films formed from an emulsion of the copolymer would become more flexible and hence softer One would also expect that as the filmns became softer, the resistance to wet abrasion would be re 125 duced As the data given in the followinc table and plotted in the accompanying drawing clearly show, such a tendency is encountered in the case of vinyl acetate-dibutvl maleate copolymers Yvhere the proportion 130 785,406 of dibutyl maleate is below 17-t parts to 82-, parts of the vinyl acetate, but as the proportion of dibutyl maleate is increased the tendency is reversed until a maximum resistance is reached Increasing the

proportion of the dibutyl maleate above that corresponding with the maximum given causes a fall in the wet abrasion resistance A still good resistance is however obtained until the copolymer contains 321 parts of dibutyl maleate to 67 A parts by weight of vinyl acetate; TABLE I WET ABRASION RESISTANCE AS STROKES GARDNER Vinyl Sample A cetate % Hexylene Glycol 0 2 5 5 0 10 0 A 100 50 870 4740 6790 B 93 50 320 3020 8490 C 85 50 430 2710 5790 D 77 50 1610 4890 7650 E 70 50 450 2220 7090 F 62 5 50 270 1060 2076 G 55 50 260 1280 2090 The data were obtained in the following manner:Films of the unpigmented emulsions, which in each case had a non-volatile content of 50 %, were laid down on a clean ground plate-glass plate using a Baker gauge set at a clearance of about 0 002 " The film was then dried at room temperature for from 16 to 20 hours to give a dry film having a thickness of approximately 1 mil This small thickness was chosen in order to accelerate the test At the end of the drying period each of the films was scrubbed on a Gardner Straight Line Washability Machine using the standard Chinese hog bristle brush weighing one pound Before the start of the test the brush was thoroughly soaked in water containing 0 5 % of powdered soap in solution (specifically, Ivory Snow, the word Ivory being a Registered Trade Mark) and additional quantities of this solution were applied to the testing panel during the test at a rate sufficient to keep the sample moist at all times In each case the test was continued so until the film failed The results are presented in terms of strokes of the Gardner machine and represent the average of several runs in each case. In those instances where failure is indicacated in Table I as occurring at 50 strokes failure actually occurred at somewhat less than fifty strokes and was due to the reemulsification of the film In all other instances, the failure was due to the erosion of 6 Othe film and the test was concluded when any portion of the film had completely worn away. The samples above were prepared in the following manner: In each case the following solution was first preparedAmmonium persulphate 0 3 Sodium bicarbonate 0 18 Dioctyl ester of sodium sulphosuccinic acid (Aerosol OT) 70 (the word Aerosol being a Registered Trade Mark) O 1 Polyvinyl alcohol 4 0 Water 78 0 There was then added to the solution slowly 75 and with vigorous agitation 100 grams of vinyl acetate or vinyl acetate in admixture with dibutyl maleate as follows: Sample A Sample B Sample C Sample D Sample E Sample F Sample G The resulting gran 93,, 7, 85,, 15,, 77, 23, 70,, 30,, 62.5, 37.5, 55,, 45,, aqueous as of vinyl acetate vinyl acetate 80 dibutyl maleate vinyl acetate dibutyl maleate vinyl acetate dibutyl maleate 85 vinyl acetate dibutyl maleate vinyl acetate dibutyl maleate vinyl acetate 90 dibutyl maleate

emulsion was then transferred to a reaction flask equipped with a sealed stirrer, a thermometer and a reflux condenser, and heated while being agitated 95 to a temperature of from 67 to 680 C, and maintained at that temperature until the polymerisation reaction was initiated As the polymerisation reaction continued, the temperature was permitted to rise very 100 slowly to from 75 to 80 WC The reaction was thereafter maintained at that temperature The reaction was continued until the residual monomer content as determined by titration was less than 1 % The emulsion 10 was then cooled to room temperature and sufficient sodium bicarbonate was added to adjust the p H to from 4 5 to 7 O Sufficient quantities of a solution of equal parts by weight of hexylene glycol and water 110 were added with stirring to three portions of each of the samples to give concentrations of hexylene glycol, expressed as per cent by weight of the copolymer of 2 5, 5 0 and 10 0 respectively In a variation of the procedure, 115 the hexylene glycol solution may be added to the polymerisation mixture as a portion of the water needed to make the emulsion without any adverse effects and with the advantage that the resulting final emulsion 120 has a higher total solids content. Instead of the dioctyl ester of sodium sulphosuccinic acid, there may be used other wetting agents, e g, the sodium salts of the alkyl sulphonates, the esters of the alkyl 125 sulphonates, the sulphates of the higher alcohols, the ethylene oxide condensation products of the alkyl phenols or the polyethylene glycols of the fatty acids. The polyvinyl alcohol used as an emulsi 130 785,406 fier is a hydrolyzed polyvinyl acetate prepared by hydrolyzing a polyvinyl acetate having a viscosity of between 7 and 100 centipoises in molar solution in benzene, to a residual acetate content of from 1 to 25 %. The preferred concentration range of such an emulsifier is between 3 and 7 % O based on the weight of the monomer. In order to illustrate the use of glycolstabilisers other than hexylene glycol, different glycol-stabilisers were added to aqueous disnersions of a copolymer formed from 77 by weight of vinyl acetate and 23 % by weight of dibutyl maleate, the amount added being 5 %' by weight based on the copolymer. The resulting emulsion paint vehicles were tested for wet abrasion resistance The method of preparation and the test procedure were similar to those described in connection with Table I and the following results were obtained. TABLE II Wet A brasion Glvcol-Staibilisetr Resistance as Strakes Gardner 3-chloro 1, 2-propanediol 2900 2-(beta-butoxv-ethoxy)ethanol 5160 2-butoxy-ethanol acetate 2510 2-(beta-butoxy-ethoxy)ethanol 3450 Dipropylene glycol 5710 In order to illustrate the use of comonomers

other than dibutyl maleate dispersions were prepared of copolymers obtained from di-esters of maleic acid with different alcohols ( 23 %i by weight) and vinyl acetate ( 770 % by weight), 10 ' by weight, based on the copolymer, of hexylene glycol being incorporated in each dispersion The resulting emulsion paint vehicles were tested for wet abrasion resistance The methods of preparation were similar to those described in connection with Table I and the following results were obtained:TABLE 1 l Wet Abrasion Co-Monomier Resistance as Strokes Gardner Diethyl maleate 9720 Dilsopropyl maleate 7270 a, D i(methyl-amyl)maleate 15090 Di-2 ethylhexyl maleate 5610 On comparative tests using, as the comonolmers pure maleate esters, the corresroonding pure fumarate esters, and the corresponding mixtures of maleate and ulmarate esters no significant differe:-nce was noted. The water based paints provided by the invention are particularly useful for both en interior and exterior use They are charact, iscd by permanent flexibility since the vehicle neither loses its plasticiser content nor is it subject to oxidation As an illustration or such permanent flexibility three pnints were prepared identical in formulation except that two were based on an externally plasticised polyvinyl acetate emulsion and the third was based on the 77-23 copolymer referred to above, which is the preferred vehicle of the invention These 70 paints were drawn down to equivalent film thickness on tin plate panels which were aged at 60-C for 8 days in an oven with circulating air and then cooled to room temperature and bent through 90 degrees over 75 a -' inch mandrel The films of both paints based on externally plasticised polyvinyl acetate ruptured in this test wvh 1 ereas the paint film based on the vehicle of the invention remained unaffected S O Another particular advantage of the paints is that they have a vastly improved ability to consolidate at low temperatures Even at temperatures where paint filns based on externally plasticised polyvinyl acetate emul 85 sions fail to consolidate, paint films based upon the present vehicles exhibit good consolidation. This can be shown by measuring the specular reflectance of lpaint films Samples 90 were prepared by applying films of water based paints to giypsum-board panels at a reduced temperature and drying these films at the reduced temperature in a storage chest lhaving circulating air and a relativ e humnidity 95 of 507 ' or less Prior to the test the paints. the test panels and the brushes used in applying the paint were stored in the chamber for a time sufficient to ensure that the temperature of each had come to equili 1 jo brium After the films had dried the samniles were allowed to attain roonm temperature and one coat of a semicloss o;l based lvall paint was applied over the test iflms After

this coat lhad dried the srecular reflectance 1 o 5 of each sample was mfleasured on a H-1 unter reflectometer according to the procedure set forth in the JOURNAL OF RESEARCH of the National Bureau of Standards. Volume 25 pages 582-618 November, 1940 110 The reflectance is a measure of the consolidation of the priming coat of weater based paint For examnple the refectanc of a film of semi-gloss paint wbian anplied to an unprimed board is less than 07, the minimum 115 reading of the refiectometer. With samples Dreipared nt a temperature of 'F reflec'tance in eqlch instance ewas about the same with a realof bcetween 5 2 and 5.6 The,re 9 t c's t in eiflectance 120 occurred in sampl irepred at a temperature of 50 WF A th t na mrature a paint Using a st aight pol'v 1 acetate emulsion as a vehlicle gave a rendinv of C 7: w 5 hereas. paints usiln a 77-23 oolver of vinyl 12 o 5 acetate and dibntvl mal-eate cave readings of 2.4 w 'ith 5 I hexzyle-ne glycol 3 7 with 10 ' hexeylne glycol, and 1, 8 w Vit:l 17 %' hexy X/lene glycol. In addition the water based paints have a 130 785,406 sufficient degree of moisture permeability to allow the passage of moisture which would otherwise remain trapped and cause unsightly blisters or peeling To show this, two identical panels of wood were taken. One of these was painted with an oil based primer followed by two coats of the conventional oil based paint, according to the recommendations of the manufacturer The other panel was painted with two coats of a paint based on the preferred 77-23 copolymer vehicle The two panels were then sealed with caulking compound to the open sides of a five gallon square can and the unpainted backs were exposed to a temperature of 50 to 60 WC and a relative humidity of 1000 o for a period of 48 hours The wood panel painted with the oil paint showed extensive blistering where the trapped moisture was unable to escape The panel painted with the paint based on the preferred vehicle remained completely unaffected. The particular paint used in both of the above tests was made as follows: The following ingredients were combined and form a paste which could conveniently be stirred on a paste mixer and mixed thoroughly: Rutile titanium dioxide 275 Ibs. Diatomaceous earth 70 Phenyl mercuric borate O 1 Polyvinyl acetate 10 , solution 40 in water Water dispersible soya lecithin 10 Surface active agent 4 Water 25 lbs of water were then thoroughly stirred in and the paste given one pass through a high-speed stone mill If a roller mill is used, some or all of the last addition of water should be held out and added after the milling operation. With the paste in a thinning tank, the following ingredients were then added and stirred in well:

Preferred vehicle ( 77-2 '3 copolymer) Methyl cellulose ( 4000 viscosity grade) 40 ', solution in water lbs. 432 Water 25 Water and/or methyl cellulose solution for adjustment of viscosity 59 An alternative method of preparing a white paint is as follows: Stir the following in paste mixer, then grind in high-speed stone mill A roller may be used if some water is held out. Rutile titanium dioxide Dry ground mica Methyl cellulose ( 4000 vis) 4 %', solution in water Ibs. 280 Water 175 Add 2 lbs of Rosin-Ethylene oxide adduct and 50 lbs of water and stir but avoid foam Add 8 Ibs of Bacteriostatic agent, stir, and adjust viscosity Add 420 Ibs of the preferred vehicle and stir thoroughly 70 Add 20 Ibs of water and/ or methyl cellulose solution to adjust viscosity. The emulsion paint vehicles provided by he invention appear to be compatible with ill of the compounding ingredients normally 75 used in water based paints and appear to require no special precautions other than those ordinarily taken in the manufacture of paints using externally plasticised polyvinyl acetate as the vehicle Calcium based 80 titanium pigments should be avoided, since, although they do not de-stabilise the emulsion, they do render the film more water sensitive Also, because the paint made from such an emulsion is normally slightly 85 acid, the lithopones should be used with caution and only after thorough testing. A cementitious coating material as provided by the present invention derives considerable advantages from the presence of 90 the emulsion paint vehicle Since it is selfsetting, it is important that no more should be prepared at any one time than will last for from thirty minutes to an hour It is suitable for application to all types of sur 95 faces and may be applied by brush or spray. In the case of metal surfaces it is necessary only to remove the loose scale and rust, and if present, any oil or grease films or oil base paint coatings In the case of masonry sur 100 faces or other surfaces which will absorb loisture the surface should be wetted down with water before applying the paint, to ensure adequate hydration of the cement content of the paint It is not necessary, 105 however to cure the cement paint by means of a water spray or with wet burlap or the like. Any hydraulic cement which may be used in cementitious coating materials may be 110 used as the hydraulic cement component of the cementitious coating material provided by the present invention. Where ordinary weathering is involved regular Portland cement (ASTM Type 1)115 may be used satisfactorily Where the surface to be coated is a metallic surface which will be exposed to such corrosive

materials as sea water, acidic waters, salt spray or acidic industrial fumes, a high alumina 120 cement for example that known as "Lumnite" should be used Where moderate exposure to acidic or sulphate waters is involved low C 3 A Portland cement (ASTM Type 2) may be used For severe exposures where 125 a high alumina cement is not available, a Portland cement of very low CA content (like modified oil well or ASTM Type 3) may be used Of course, if colour is important, white Portland cement can be used for 130 785,406 light colours or coloured cements or suitable pigments for particular colours Unlike cementitious coating materials incorporating an ordinary polyvinyl acetate emulsion, those provided in accordance with the present invention are water resistant and vill withstand continuous water immersion without softening or disintegration They have moreover improved adhesive properties and for a given water content a higher plasticity. A cementitious coating material as provided in accordance with the present inedndion, especially when of pasty consistency, is useful as a binding medium in the process of applying a layer of nortar or concrete to the surface of mortar or concrete When intended for this purpose the composition of the cementitious coating material is Drefero ably such that it contains for every 20 parts by weight of the non-volatile content of the emulsion paint vehicle, about 100 parts by weight of the hydraulic cement and from 20 to 40 parts by weight of water A preferred procedure comprises applying to the surface a coating of the cementitious coating material and before the coating has dried applying thereover a layer of mortar or concrete. In a typical procedure the surface is cleaned of oil, grease, loose material and all foreign matter and then dampened with wiater, A cementitious coating material as provided in accordance with the present invention and having the consistency of a fairly thick brushable paint, is spread over the surface, preferably with a stiff bristle brush or a stiff broom in order to work the coating material into the irregularities of the surface. The new mortar or concrete is then applied imimediately, in normal manner It has been found that the bond strength resulting when the new mortar or concrete is added without permitting the coating material to dry is about twice that obtained when the coating 4.5 material has been permitted to dry In either case, the strength of the bond caused by the coating material is usually greater than that of either the new or old mortar or concrete. Advantageous results are also obtained should a final trowelling or finishing operation be needed, by using a very dilute skim coat of the coating material as the topping. An iron or steel article may be protected against corrosion by a method provided in -55 accordance with the present invention which

method comprises coating the surface of the article with the cementitious coating material. A typical satisfactory cementitious coating material for this purpose contains about parts by weight of hydraulic cement for every 5 parts by weight of the non-volatile content of the emulsion paint vehicle and a water content sufficient to give a paintable consistency. The properties of such a material are surprising Its adhesion to iron and steel is such that an iron or steel sheet having two coats of material thereon can be bent through 90 without the material cracking 70 or flaking off The material gives exceptional properties of rust resistance, and can be applied even to corroded metal to give coatings which are durable and prevent initial or further corrosion of the metal 75 Steel plates painted with the material showed no rusting even after 1224 hours of exposure in an Atlas Weatherometer whereas steel plates coated with a high-grade oil base rust preventative paint showed rust spots under 80 the same conditions at the end of 360 hours. The material is also particularly effective where acidic or other types of corrosive waters are involved and may be used to protect structural steel subject to weathering 85 and corrosive industrial fumes for much ioniger periods of time than is possible with conventional rust preventative paints.

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* GB785407 (A)

Description: GB785407 (A) ? 1957-10-30

Motor-driven machine for the purpose of tensioning and closing a loopapplied about a packed article

Description of GB785407 (A)

COMPLETE SPECIFICATION Motor-Driven Machine for the purpose of Tensioning and Closing a Loop applied about a Packed Article We, A. G. FUR TECHNISCHE NEUHEITENC a Swiss Corporate body organised under the laws of Switzerland, of Binningen, Basel, Switzerlandl, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method: by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a motor-driven machine for the purpose of tensioning and closing a loop applied about a packed article. It ds known to loop wire or banding round a pack and to close the two ends of the loop together after tensioning the said loop. Both handi-operated and motor-driven machines are known for tensioning and closing. The handoperated machines are easy to transport and have hand levers or hand cranks for operating the devices for tensioning and closing the wire or banding.. Operators have to apply considerable force in order to actuate these machines, and over a period of time they strain and tire the worker, especially in the case of packs which required movement over a relatively long distance for tensioning the loop, e.g. packs with very yieldable contents. In these cases the loops often have to be subsequently thightened several times and this takes up a good deal of time. In addition, it is not always possible with these machine to tension the wire or strapping uniformly, since the tension obtained in a particular case depends on the force which operator happens to apply., But the overtensioning of the wire or strapping which this causes is undesirable, since it is generally the cause of the wire or the strapping bursting during transport or when the pack is dropped. Among motor-driven machines, a readily transportable wire-tensioning machine is known, but it has only a limited tensioning distance It is provided with lifting discs and tensioning arms, and automatically accomplishes the transition from the tensioning operation to the twisting of the wire ends directly after the tensioning operation This machine has the disadvantage that ;the limited tensioning distance over which the wire arranged about the pack is tensioned is insufficient in the case of large packs, and par ticularly with yieidable packs, to give the binding wire the requisite tension before its ends are twisted. It is true that other motor-driven machines for tensioning and closing a closure band have devices for adjusting the band tension,

but these machines do not permit subsequent tensioning of the band before the closing operation; they also do not permit the tension to be adjusted during the tensioning operation or after it hasl ended, since the closing opera tion follows immediately upon the tensioning operation Consequently the particular tension of the band depends on the tension limit which is set in the tensioning device, the ten sioning operation is automatically interrupted after the said limit is exceeded, and the clos ing operation then comes into play. However, the requisite adjustment of the tension can not alwaysl be accurately. judged before the loop is tensioned. 'Consequentiy work carried out with these machines is not always satis factory. An object of the invention is ko construct a motor-driven machine of this kind in such a way that the tension of the loop can be adjusted even after completion of the ten sioning operation and; before commencement of the closing operation. The invention pro vides a motor-driven machine for tensioning and closing a loop applied about a pack, the said machine comprising a tensioning device which is adapted to thighten the loop and is driven by way of a slipping clutch, and a clos ing device which is driven from the same motor and is adapted to connect together the loop ends, the tensioning device being auto matically stopped when the loop tension exceeds a value determined by the force-trans mining capacity of the -slipping clutch, wherein the tensioning device and the closing device are each driven by way of a control clutch operable to complete the drive. The slipping clutch can at the same time serve as the control clutch for the tensioning device It can consist e.g. of an electromagnetic coupling whose force-transmitting power can be regulated by means of a variable resistance, the electromagnetic clutch being associated with a switching member in such a manner that it interrupts the supply of current to the clutch in order to slip the said clutch. The machine provided by the invention combines the advantages of the hitherto known motor-driven machines and of the hand-operated

machines, wherein the tensioning and closing operations are separated from one another in time, without having the aforesaid disadvantages of these two types of machines. It allows the loop which is arranged about the pack to be tensioned by means of a mo.tor after the conclusion of the tensioning operation controlled by the slipping clutch and before the closing device is brought into operation, since, after the conclusion of the tensioning operation, the machine can first of all run idly before the control clutch for the closing device is operated. The control clutch for the closing device is operated only after the optimum loop tension has been found by subsequent tensioning one or more tines. The machine can be so constructed that this control clutch can optionally be operated automatically, - so that, in the handling of a number of similar packs, once the correct tension limit for stopping the tensioning operation has been found and set the control clutch for the closing device is automatically controlled for the whole of the subsequent series. Embodiments of the machine provided by the invention are illustrated in the accompanying drawings, in which: Figure 1 is a front elevation of a band tensioning and closing machine, Figure 2 is a side elevation viewed in the direction of the arrow 148 in Figure 1, and Figure 3 is a plan view thereof. Figure 4 is a cross-sectional view taken on the line A-A of Figure 1 vith control clutches disengaged by hand. Figure 5 is a similar view showing the control clutch of the tensioning device in the engaged condition. Figure 6 is a similar view showing this control clutch disengaged by the slipping clutch. Figure 7 is a rear elevation of the driving mechanism, partly in section taken along the line BaB of Figure 8. Figure 8 is a plan view thereof. Figure 9 is a.similar view to that of Figure 1, showing the part comprising switch, eccentric and closure plunger. Figure 10 is a plan view thereof. Figure 11 is a sectional view taken on the line SC of Figure 10. Figure 12a is an elevation of the eccentric. Figure 126 is a plan view thereof. Figure 13 shows in its upper half a sectional view taken on the line D-D, and in its lower half a sectional view taken on the line E-E, of Figure 14, which in a similar view to that of Figure 4 shows a further embodiment of the slipping clutch part.. Figure 15 is a view similar to Figure 5, and shows a construction in

which the slipping clutch is modified so that it also acts as the control clutch for the tensioning device. Figure 16 is a front elevation of a machine for tensioning and twisting wire. Figure 17 is a side elevation thereof seen in the direction of the arrow 149. Figure 18 is a sectional view.taken on the line FF of Figure 16. Figure 19 is a part of a sectional view taken on the line G-G of Figure 18. Figure 20 shows, in a similar kind of view to Figure 16, an embodiment having changeover means which can be operated automa;tically or manually as desired. Figure 21 is a plan view thereof. The band closing machine shown in Figures 1 to 12 comprises a bed plate 1, as is shown most clearly in Figures 1 and 2. Fixed to this bed plate is a housing 2 covered at the top by a cover plate 3. The latter is formed with a vertical hole into which is inserted a threaded sleeve 4 indicated in Figures 2 and 7. A vertical spindle 5 engages with the said sleeve. Fixed to the cover plate 3 is a gear casing 6 which contains a speed reduction gear driven by a motor 7. As Figure 7 shows, the housing of this motor has a centering pin 14 which is inserted in a corresponding hole in the adjoining wall of the casing 6. The motor shaft 11 is guided centrally through a bearing hole in the pin 14. The said shaft is provided, as shown in Figure 8, with a worm 12 and is mounted on the opposite wall of the casing 6 in a sleeve 13. The worm 12 engages with a worm wheel 10 which is keyed into a vertical shaft 8. As shown in Figure 7, the shaft 8 is rotatably mounted at one end in a journal bearing inserted in the base of the casing 6 and at the other end in a bushing 9 fitted into the bed plate 1. Mounted on the shaft 8 is a worm 15 which meshes with two worm wheels 16, 17. According to Figures 4 and 6 the worm wheel 17 is keyed on a hub 1 8a mounted on a cylindrical clutch housing 1.8. At the opposite side the housing 18 is open and is provided with internal screwthreading into which a cover 19 is fixedly screwed. The latter is at the same time constructed as one half of a slipping clutch and is provided at the inside with helical teeth 20 which engage with corresponding helical teeth 20 on a clutch half 21 which is arranged in the bearing 18 in such manner as to be axially displaceable with respect to the first half. The clutch half 21 is under the influence of a clutch spring 22 which is arranged in the housing L8 and bears at the other end against the bottom of the housing. This spring is a compression coil spring which has been pre-tensioned to a pre-determined value. The clutch half 21 is longitudinally

displaceable on a hollow shaft 23 on which the hub 18as is so mounted as to be freely rotatable., The hollow shaft 23 is in turn mounted in a bearing 4L which is arranged displaceably in a corresponding part of the housing 2 so as to be displaceable in the transverse direction in a manner which will be indicated hereinafter. The hollow shaft 23 is secured against axial displacement in the one direction by an adjusting' ring 24 which bears against the cover 19.. Longitufinally displaceable in. the hollow shaft 23 is a control rod 37 to which the displaceable clutch half 21 is fixed by means of a transverse pin 25 which extends through a bosslike extension of the clutch half 21, the said pin being guided through two slots 26 in the hollow shaft 23 which are situated diametrically opposite one another. At the opposite end portion the hollow shaft 23 comprises further slot 39. The axes of the slots' 26 and 39 extend in the axial direction of the hollow shaft. Guided through the slot 39 in a transverse pin 38 which is mounted in a suitable transverse hole in the control rod 37 and is guided outside the slot 39 by a further slot 40 extending through the sleeve 27 of a control coupling. The sleeve is mounted ion the hollow shaft 23l so as to be longitudinalllly displaceable but prevented from rotation by a sliding key 28 and comprises on its inner end face dogs 29 which co-operate with dogs 30 of a non-displaceable clutch half of which is constructed as a tensioning wheel 31. The tensioning wheel 3.1 is rotatably mounted on the hollow shaft 23 by means of a bushing 33 and is secured against longitudinal displacement on the one hand by a flange 42 of the bearing 41 and on the other hand by a collar on the hollow shaft 23 It is provided over the whole of its periphery with pointed teeth 32 which are interrupted in the middle by an annular groove which is milled out from the wheel 31. At the side facing the flange 42 the wheel 31 is provided with a hub on which is mounted a locking wheel 34 which is connected to the hub by means of pins 35. Engaging with the teeth 36 is a pawl ,70 which, as shown in Figures 1 and 4, is pivotally mounted in the housing 2 by means of a bearing pin. which is secured into the housing 2 and is formed by a screw 69, and the said pawl is held positively in engagement with the teeth 34 by means of a spring 71. As is shown in Figure 1, a plate-shaped abutment 100 is fixedly arranged on the bed plate 1 under the tensioning wheel 31 and is provided at its upper side with pointed corrugations 'which, like the teeth 32, extend parallel to the axis of the tensioning wheel. The tear- ing 41, which is secured against axial displacement in the housing 2 by the flanges 42 provided at both ends, is mounted in a bearing 43 which is shown in Figure 7, so as to be displaceable in the direction towards the abutment 100 ii.e. in the vertical direction. It comprises at the upper end a central cylindrical recess

in which an annular disc 44 is rotatably mounted.. The latter is mounted on the lower end' of the spindle 5 andi is secured by a cover disc 45 against axial displacement with respect to the bearing 41, the said cover disc being fixed to the body of the bearing 41 by screws which are not shown and is provided with a hole for the passage of the spindle 5 which is mounted! also in the general bearing 46 arranged on the gear casing '6., Fixed to the upper end of the shaft 5 is a hand wheel 47. lBy turning the hand wheel 47 the spindle and therefore the tensioning wheel 31 can be adjusted to various heights, at which it is secured in ;self-locking manner by means of the screw-threading. The worm wheel 116 is mounted, as shown in Figure 4, a shaft 48 which is parallel to the hollow shaft 23 'and is mounted by means of a 'bearing bush 516 in the same part of the housing 2. The bush 56 is. fixedly secured in this housing part. The wheel 1.6 bears on the .one handi against the bush 56 and on the other hand against an adjusting ring 49 mounted on the shaft 48. A!t the opposite side of the bush 56) an eccentric disc 54 is freely rotatable on the shaft 48 and secured against longitudinal displacement by a collar of the said shaft., It comprises a toothed segment 57 which extends over pant of the periphery as shown in Figure 12at. At the side remote from the bush 56 the eccentric disc 54 comprises dogs 53 with which there cooperate corresponding dogs 52, which are mounted on a clutch coupling sleeve 50., The latter is mounted on the shaft 48 in such manner as to be fast against rotation thereon but longitudinally displaceable by means of a sliding key 51, and is secured against being pulled off by a disc 55k, which is fixed' lobby a central screw two the shaft 48. According to Figures 9 and 10, the toothed segment 517 of the eccentric disc 54 co-oper- ates with a small toothed wheel 59 which is mounted on the rotatable part of a switch 58 for the motor current, said rotatable part comprising a switch knob S for hand operation This switch is fixed to the housing 2 as shown in Figure 11 and, as shown, in Figure 11, comprises a switching element 58a which co-operates with corresponding fixed contacts for switching the motor current on and off. Also fixed to the housing 2 is a tbox-llike casing 60 which forms a vertical guideway for a closing plunger 62. This is provided at eack side with pins 63 which each project through a slot 64 in the housing 60. Engaging one each on the free ends of the pins 63 are restoring tension springs 65 whose other ends are fastened to pins 66. The pins 66 project from the housing 2 in which they are fixed. The housing according to Figure 9 is provided at the underside with a recess 61 for guiding a closing sleeve which is to be inserted into said housing. Located under the said sleeve is a matrix 57 which is fitted into the bed plate 1 and fixed therein, and with which a matching

stamping cam 68 mounted on the lower end of the plunger 62 co-operates. The stamping cam 68 is adapted to the particular type of closure chosen for the band, depending on whether the machine is intended to operate with or without closure sleeves. According to Figures 1 and 2, there is fixed to the housing 2 a bearing fork 72 between whose arms 73 an upright hand lever 75 is articulated by means of a bearing pin 74. According to Figure 1 the lower end of the hand lever 75 is provided with semi-circular fork legs which half-surround the sleeve 27 and are each provided at the end portions with a concentric pin 76. The pins 76 engage into an annular groove 77 which is milled in the middle part of the sleeve 27, so that by swinging the hand lever 75, the sleeve can be axially displaced on the hollow shaft 23 and the dogs 29 can be brought into engagement with the dogs 30. A further bearing fork 78 is fixed similarly on the housing 2, and between its fork legs 79 a further hand lever 81 is pivotally mounted by means of bearing pin 80, said lever 81 being likewise provided with semicircular fork legs in which are mounted coaxial entrainment pins 82 which face one another and which engage in an annular groove 95 milled from the clutch coupling sleeve 50. Therefore, by rocking the hand lever 81, the clutch coupling sleeve 50 can be axially displaced on the shaft 48, so that the dogs 52 of the said sleeve can be brought into engagement with the dogs 53 of the eccentric disc 54. As shown in Figures 1-3, a holder with a terminally spherical handle 97 is fixed to each side of the housing 2 By gripping these two handles, the operator can bring the machine into the position of use, mounting the machine with its bed pla;te 1 on the pack which is to be dealt with, in the manner shown in Figure 1 for the pack 99, only the upper side of which is illustrated. The steel band which is provided is then laid about the pack 99, forming the usual loop on to which may be fitted a closure element which comes to bear against the loop ends engaging over one another. The steel band together with the sleeve is then pushed forward, from the front into the machine so that it comes to lie centrally under the tensioning wheel 31 and the plunger housing 60 In order to tension the band, the spindle 5 and with it the hollow shaft 23 together with all the parts arranged on the said shaft are moved downwards first of all by turning the hand wheel 47, the bearing 41 sliding in the aforesaid vertical guide 43. The tensioning wheel 31 then comes into engagement with the steel band and clamps the band fast with respect to the corrugated abutment 100. During this downward movement the worm wheel 7 rolls on the worm 15 (Figure 7). The motor 7 is then switched on by tuming the switch button S in the direction of the arrow shown in Figure 9, and thus the motor is started up if it

has not already been brought into operation before. The motor, by way of the worm 12, the worm wheel 10, the worm 15, rotates the worm wheels 16 and 17 in opposite directions as illustrated by the directions of the arrows shown in Figure 7.. The clutch housing 18 with the clutch half 19 participates in the rotation of the worm wheel 17. Due to the fact that the clutch half 21! is pressed against the clutch half 19 by means of .the spring 22, the clutch half 21 participates in the movement and entrains along with it, by means of the transverse pin 25, the hollow shaft 23 and the control rod 37. By means of the transverse pin- 38 the rotary movement is transmitted to the sleeve 27, which rotates in the direction of the arrow shown in Figure 1 fcr the tensioning wheel 31. Then the operator, gripping the handle, swings the lever 75 in the direction of the arrow indicated in Figure 2, which has the result that the sleeve 27 is shifted correspondingly and consequently the dog clutch is engaged so that the dogs 29 and 30 come into engagement with one another. By this means the tensioning wheel 31 is rigidly connected to the sleeve 27 (Figure 5). The transverse pin 38 of the control rod 37 which up to this time was bearing against that flange a of the sleeve 27 which bounds the slot 40 as shown in Figure 4, now bears against the opposite flange b as shown in Figure 5. Since the lower loop end E (Figure 1) of the steel band bears against the corrugated abutment 100 and on the other hand the upper loop end is pressed by the pressure of the teeth of the tensioning 31 against the lower loop and, E, the rotation of the tensioning wheel in the direction of the arrow shown in Figure 1 causes the upper loop end, which is entrained by the tensioning wheel, to be pushed away correspondingly with respect to the loop end E 'which is held fast by the abutment 100. By this means the loop is drawn tightly about the pack 99 with a tension which increases according to the resistance of the pack. Increasing band tension requires a corresponding increase in the driving moment which is to be transmitted to the clamping wheel, transmission being effected by way of the slipping clutch 19, 2.1. However this clutch has only a limited forcetransmitting capacity, which is determined by the pre-tensioning of the spring 22 and the height of the teeth 20., If the torque exceeds this value, the teeth of the clutch half 19 slide over the teeth of the clutch half 21. Owing to the oblique tooth profiles the result is that the clutch half 21 is pushed positively downwards, namely by an amount correspond, ing to the height of the teeth. By means of the transverse pin 25 is entrains the control rod 37 along with it. The transverse pin 38 bears against the fi k Blank 'of the sleeve 27 and carried this sleeve along with it, and therefore brings the dogs 29 out of engagement once more with the dogs 30 (Figure 6).

In this condition the transverse pin 38 bears against the lower limit of the slot 39. Consequently, the clutch coupling sleeve 27, together with the hollow shaft and the control rod, runs idly, and this has -the result that the coupling spring 22 brings the coupling half 21 once more into the position shown in Figure 4 with the teeth 20 engaged. The tensioning wheel 31, left to itself, retains its position since it is arrested by the pawl 70 which engages in the teeth 36 of the ratchet wheel 34. Consequently the band remains tensioned to the slame degree. The machine then runs idly since the second control clutch with the dogs 52, 53 runs idly and consequently the worm 15 drives idly, the worm wheel 16 and thereby the shaft 48 and the sleeve 50.. Consequently the operator can then check the band tension which he has proreduced and ascertain whether it comes up to requirements. If this is not the case and if a greater hand tension is required, the operator can provide the slipping clutch with a correspondingly higher spring tension, either by interchanging the clutch springs 22 or by increasing the pretension of these springs if means are provided for this purpose. Although s:uch means are not provided in the case of the embodiment which has been explained, means of this kind which can be used in ;the present case will be discussed later hereinafter by way of example. As soon as the operator has set the desired band tension in this, way by modifying the spring tension one or more times and subsequently re-engaging the sleeve 27 by means of the hand lever 1750, he puts, his hand on the handle of the lever 81 whilst the machine is once more ruirning idly and moves the said lever also in the direction of the arrow which is indicated in Figure 2 for the lever 75, which results in a corresponding axial movement of the sleeve 50 on the shaft 48 and therefore in the engagement of this control clutch by the inter-engagement of the dogs 52 with the dogs 53. The result is that the eccentric disc 54 is coupled to the sleeve 50 and thereby to the motor drive. The eccentric disc 54 turns in the direction of rotation indicated in 'Figures 1, 9 and 11 for the shaft 48. During this operation the influence of the eccentric disc 54 causes the plunger 162. to be shifted downwards and the stamping nose 68 deforms the middle part of the superjacent loop ends into the desired closure force, ,together with the closure sleeve which is pushed over these ends if such a sleeve has' been. inserted in the guide 61. After the movement of the plunger has been completed, the toothed segment 517 of the eccentric disc 54 comes into engagement with the small toothed wheel 5:9 and- thereby brings the switching element S--8a into the transverse position which is illustrated in Figure 11 and in which it is out of contact with rhe fixed switch

contracts, in contrast to the previous vertical position. As a result, the motor current is interrupted' at the switch !S and therefore the motor is stopped. The peripheral length of the toothed segment 5;7 is so dimensioned that its teeth come out of engagement with the small toothed' wheel 59 as soon as the switching element 58 is in the middle position between the fixed contacts as illustrated in Figure 11. This position is advantageously; secured positively by a snap closure as currently used in switches. The operator then grasps the hand lever. 81 once again and disengages the dog clutch 29, 30. The plunger 62 is brought back slipping of which automatically disengages the tensioning means, there is now provided a slipping clutch in the form of a mere friction clutch, and therefore the control clutch for the clamping device must be disengaged' independently of the slipping clutch and by hand as soon as the slip of the slipping clutch shows that the tension of the band loop determined by the clutch spring has been reached. According to Figures 13 and 14, a clutch sleeve 86 which is fixed to the shaft 85 is arranged in a cylindrical clutch housing 83 which is connected rigidly to the worm wheel 17 and which is freely rotatable on the shaft 851 mounted directly in the bearing 41 The wall of the housing 83 is provided with four elongated. slots 84 and the sleeve 86 is provided zwith four elongated slots 84 and the sleeve 86 is provided at its exterior with four longitudinal slots 88. Situated in the annular space between the sleeve 86 and the wall of the housing 83 is a bundle of laminations. or discs which consists alternately of discs 90 which are designated as the outer discs and which comprise four projections 91 engaging in the longitudinal slots 84 and of discs which are designated as the inner discs 92 which comprise inwardly projecting projections 93 engaging in the longitudinal slots 88, and also of the friction rings 94 situated between the outer and inner discs.. The said rings are each provided with a friction lining. The bottommost disc bears against the flange of the clutch sleeve whereas the topmost disc is under the influence of a clutch spring 96 which is constructed as a compression coil spring and which bears at its other end against a nut 8!7 secured by a lock nut, and screwed on to corresponding threading on the clutch sleeve 86.. The tension of the spring 96 can be varied by loosening or tightening the nut further and securing it again by means of the lock nut. The bushing 33 disposed in the tensioning wheel 31, is directly mounted in rotatable fashion on the other end of the shaft 85, and the said bushing is secured against longitudinal displacement at one end by the bearing flange 42 and at the other end by a collar provided on the shaft 85. The clutch coupling sleeve is mounted on the shaft .85 directly by means of the slide key 28 so as to be fast against rotation but longitudinally displaceable, and is again in engagement,

in a manner which is not illustrated, with the entrainment pins 76 of the coupling lever 75 Operation proceeds in the same manner as in the case of the embodiment which was at first described, the sleeve 217 being first engaged by operating the hand lever 75 and thus the dogs 29 are made to engage 'with the dogs 30. Owing to the frictional power under the pressure of the spring 96 the housing 83 is connected in a frictionally locking manner to the clutch coupling sleeve 86, so that the motor drive of the worm wheel 1.7 is transmitted to the shaft 95 until the torque to be transmitted to the tensioning wheel 31 has become so great that the discs in the slipping clutch begin to slip with respect to one another. This step is visibly obvious to the operator, who sees that the tensioning wheel 31 is stopped and, by operating the hand lever 75, he changes the sleeve 27 back to the starting position, disengaging the dogs 29 from the dogs 30. If owing to insufficient tension of the band loop, subsequent tensioning is necessary, the clutch spring 96 is tensioned more tightly accordingly and hand lever 75 is again engaged, which, in accordance with the increased frictional pressure, results in the shaft 85 being once more entrained by the slipping clutch, until the clutch again slips when an appropriately higher torque is reached, whereupon the operator again disengages the dog clutch by means of the lever 75. The embodiment shown in Figure 15 differs from that according to Figures 1 to 12 only as regards the part illustrated in Figure 5. As will be seen by comparing this with Figure 15, the clutch coupling sleeve together with the transverse pin 38 and the slot 40 are dispensed with, including the dogs 30 on the tensioning wheel 3f1, Instead, the tensioning wheel 31, according to Figure 15 is fixed directly to the hollow shaft 23 by means of a key 150 so as to be non-rotatable and nondisplaceable on the said shaft. The control rod 37 comprises a slot 151 which is limited. at the side towards the end of the rod by a flank d which is directed somewhat obliquely with respect to the transverse direction.. Guided through the slot 151 is a pin 152 whose head is displacably mounted in non-rotatably fashion in a slot 153 of the hollow shaft 23 so as to be capable of displacement in the longitudinal direction of the pin. The pin has a cylindrical shank 154 which is longitudinally displaceable in an appropriate hole in the hollow shaft 23 and which is provided at its end lying outside the hollow shaft with. screwthreading, on which a threaded cap 155 can be adjusted and fixed in various positions by means which are not shown in the drawings. Arranged between the threaded cap 55 and the hollow shaft 23. is an

adjusting spring 156 which is constructed as a compression coil spring surrounding the shank 154 of the pin.. The shank 154 is provided at the head endawith a nose 15!7 directed towards the hollow shaft end and the said nose is located within the slot and; is limited by a wedge surface e parallel to the flank d. The nose 157 projects beyond the flank d by an amount f which is slightly less than the height of the teeth 20 of the slipping clutch halves 19, 21 (Figures 4 and 6).. In contrast to Figures 4 and 6, the clutch spring 22 is supported on a collar of the hollow shaft 23 instead of on the housing 18. In the starting position, with the tensioning wh.eel 31 not loaded, the slipping clutch as illustrated in Figure 4, but modified as described above, is engaged The control rod 37 is in the starting position shown in Figure 15 with respect to the hollow shaft 23.. Then if, during the tensioning operation, the motor drive by way of the worm wheel' 1!7 and the slipping clutch transmits a torque to the hollow shaft 23 and thence bp means of the key 150 directly to the tensioning wheel 31, the pin 152 does not participate in this operation.. As soon as the torque has increased owing to the tensioning resistance to such an extent that the clutch half 21 begins to slip with respect to the half 19, and therefore the control rod 37 is displaced in the direction of the arrow shown in Figure 15,, then the value f is reduced accordingly. As soon as! this has dropped to zero, the surface e of the nose 1517 comes into contact with the flank d of the slot 151 and is then pushed, by means; of the suitably pre-tensioned adjusting spring 156, along the flank d into the slot 151, the pin head slid; ing inwards in the slot 153., Owing to the slight taper of the flank d and of the surface e, the rod 37 is displaced further by a slight amount in the direction of the arrow, and the result is that the teeth of the clutch half 21 become completely disengaged from -the teeth of the clutch half 19. Consequently the slipping clutch is completely disengaged, so that the slipping clutch half 21 together with the hollow shaft 23 and the control rod 3i7 and the tensioning wheel 31 are stopped, the latter being again prevented from turning back by the pawl; 70. The state of tension of the steel band can now be checked.. If the band is insufficiently tensioned, the tensioning force of the clutch spring 22 is again increased in the aforementioned manner. The slipping clutch is then again engaged, the operator applying pressure in the direction of the arrow shown in Figure 15 on the threaded cap '155, and this pressure overcomes the force of the adjusting spring 155 and returns the pin once more to the starting position shown in Figure 15. The force required for this purpose is reduced by the aforementioned taper of the flank d or surface e, since the clutch spring 22 aots in the sense of displacing the pin in this direction by a wedge effect.

As soon as the pin 152 again reaches the starting position according to Figure 15, this nose 157 releases the control rod 37, with the result that the clutch spring 22 again engages the slipping clutch. The clutch is now again capable lof transmitting the increased torque, so that the band can be subsequently tensioned to the appropriate degree, after which the slipping clutch is again disengaged automatically. Instead; of the pin 152, it is also possible to arrange another control element, perhaps at another part of the slipping clutch if so desired, in such manner that due to the slipping of the clutch the said element disengages the clutch automatically until it is again engaged by actuating the 'control element in the reverse sense. In this case the slipping clutch can also be constructed differently from what is illustrated' in the drawings.. For example, it is possible to use a clutch operat- ing with elastic snap-action elements, or another of the known slipping clutches. In the case of the wire tensioning machine shown in Figures 16 to 19,, the hollow shaft 23 is rotatably but non-displaceably mounted in a bearing bush 101 in the housing 2 (Figure 18), in contrast to the band tensioning machines as hereinbefore., Moreover instead of the band tensioning wheel, a wire tensioning wheel 102 is mounted on the hollow shaft 23, again by means lof a bushing 331 which carries the dogs 30. The tensioning wheel 102 is provided with radial holes 103 for insertion of the wire end The slipping clutch differs from that of the embodiment of Figures 4 "to 6 merely in that it comprises means for arbitrarily modifying the pre-tension of the 'clutch spring 22. To this end, the spring 22 according to Figure 18 bears, at the side opposite the clutch half 21, against rhe spring cap 137 which is axially displaceable in the housing 18, and which is provided externally with radial support arms 138., These each extend through an elongated slot 139 in the wall of the housing 18 and are supported outside the housing on an adjusting nut 14Q, Which is adjustably screwed on to the externally threaded housing wail. By turning the nut 140 in one or other direction, the spring cap '137 can be axially adjusted 'correspondingly, and the pre-tension of the spring 22 varied.. In contradistinction to the embodiment shown in Figure 4 in the embodiment shown in Figures 16 to 19 the closure device comprises, instead of the eccentric disc 54, a bevelgear wheel 104 which is freely rotatable on the shaft 48 andi which comprises a bearing bush 135. The bevel-gear wheel 104 meshes with a bevel-gear wheel 105 which is keyed by a key 106 to an intermediate shaft 1017. The shaft 107 is rotatably but axially nondisplaceablyl mounted by

means of a bearing bush 108 in a bearing 109. The bearing 109 is rigidly screwed to the bed plate 1.. Fixed by means of a key 11.1 on the boss of the bevel-gear wheel 105 is, a toothed wheel 110 which comprises, at the side facing the bear- ing 109, a cup into which there projeots a locking pin 136 which is mounted for longitudinal displacement in an axial bore of :the bearing 109 and is under the influence of ,an adjusting spring 133 which is located in said bore and is constructed; as a compression coil spring, said spring urging said pin positively into the cup 134. According to Figure 1'6, the toothed wheel 110 meshes with a twisting pinion 112, which is provided with a slot 12 & open at the front. The pinion 112 is rotatably mounted with "one end in each of two bearings 113 and 114. These bearings are likewise provided each with a forwardly open slot and fixed to the bed plate 1. Secured: on the bed plate 1 at a distance from the bearing 114 and coaxially therewith is a wire guide element 115, whilst a guide element 116 is similarly secured on the bed plate 1 at the other side at a distance from the bearing 113. At the sides of the guide elements 115 and 116 remote from the pinion 112 there are mounted respectively the knife levers 117 and 118, and the latter Co- operate with the said guide elements and are pivotally arranged on bearing pins as shown by the pin 119 for the lever 117 in Figure 17. The knife lever 117 has a knife edge 158 which is so arranged that, when the lever 117 is rocked in the coun r-clockwise direction, the two steel wires 159 and 160 respectively situated close together in the slot of the guide element 115 according to Figure 17, the said knife edge can size only that wire which is furthest removed from the bearing pin 119, so that only this wire is severed whilst the other remains uninjured. The knife lever 118 is similarly constructed and arranged in relation to the guide element 116. Also arranged on the bed plate 1, at a distance from the knife 117, is a wire clamp 120 having a clamping slot through which the wire 160 is guided and clamped fast. This wire can come from a roll of wire and is guided through the wire damp through the pinion bearings 114, 113, the pinion 112 and the wire guide element 116 and then about

the pack which is to be tied and upon which the machine has been positioned resting on its bed plate 1. The free wire end 159 is threaded first through the wire guide element 115, and then crosses over the wire 160 com ing from the roll. The wire end 159 is then likewise threaded through the bearings 114, 113, the twisting pinion 112, and into the guide element 116. Thus only the wire end 159 lies in the path lof ithe knife edge 158 of the knife lever 118 as the part 160 lies outside the cutting range of the knife lever 118 and only the part 160 lies in the path of the knife lever 117. As is illustrated. in Figure 16, the free Wire end is pushed into one of the holes 103 of the tensioning wheel 102 after being bent over sharply through 909, so that when the tensioning wheel 102 is turned in the direction indicated in Figure 16, the wire end 159 is carried along with it. Provided for driving the curving mechanism comprising the knife levers 117 and 118 is a control arm 127 which, as is shown in Figure 7, is mounted on the intermediate shaft 107 and co-operates with a driving lever 123, which is mounted on a control shaft 121 and whose end portion co-operates with the knife lever 1.17. At its other end, the control lever 121 comprises an analogous driving lever 124, in whose path the knife lever 118 lies. Also mounted on the shaft 121 is an upwardly directed control arm 122 which co-operates with a switch button 130 for the motor current. The control shaft is rctatable parallel to the intermediate shaft in bearings 125 and 126, but mounted on the housing 2 so as to be incapable of longitudinal displacement. Arranged near the switchbutton 130 on the motor housing is a hand-operated motor control switch button 129. Also mounted on the control shaft 121 is a control arm 131 which faces the hand lever 81 and co-operates therewith. In order to use the wire closing or locking machine which has been described, the machine is first mounted on the pack in the manner which has already been explained, and the steel wire is looped about the pack. Then first of all the switch button 129 is pressed inwards to set the motor in operation and, by taking hold of the hand lever 75 again as in the case of the first embodiment the dog clutch 29, 30 is engaged, with the result that the tensioning wheel 102 is rotated in the direction of the arrow shown in Figure 16. In this operation the wire end 159 is wound on to the tensioning wheel 102, while on the other

hand the other wire end is held fast by clamping the wire 160 in the clamping device 120, so that the loop is thightened As in the case of band tensioning, the loop tension is limited by the set force-transmitting ability of the slipping clutch 19, 21, and the slipping of this clutch again disengages the dog clutch 29, 30 automatically and rhe machine runs idly. Then, if so desired, the wire can be subsequently tensioned. As soon as the correct wire tension has been reached, the dog clutch 52, 53 is again engaged by operating the other hand lever 81, whereby the shaft 4g drives the toothed wheels 104, 105, the toothed wheel 110 and the twisting pinion 112, together with the intermediate shaft 107 The latter rotates in the direction of the arrow shown in Figure 17. The pinion 112 twists together the wires 159 and 160 which have been inserted in the slot 128. After the twisting operation is complete, the control arm 127 of the shaft 107 comes into the region of the driving lever 123 (Figure 17). The result is that the lever 123 is rocked and entrains the knife lever 117, whilst there is a simultaneous corresponding rotation of the control shaft 121, which operates the driving lever 124 synchronously with the lever 123 and thereby also actuates the knife lever 118, whereby the loop ends are cut off at the wires 150 and 159 respectively. The control arm 131 which participated in the rotation of the control shaft 121, then comes into contact with the lever arm 8 1a of the hand lever 81 and rocks the hand lever 81 in the clockwise direc tion about its bearing pin 80 according to Figure 17, and this results in a corresponding axial displacement of the clutch coupling sleeve 50 and consequently in disengagement of the dog clutch 52, 53. The drive of the beveli-gear wheel 104 is thereby interrupted. The control arm 122 then comes into engagement with the switch button 130 and switches; off the motor current, whereby the whole machine is stopped. In order to return the moved parts of the cutting means, the knife lever 1.17 has articulated thereto, as shown in Figure 17, a restoring spring 132 whose other end is engaged on the bearing 109, The knife lever 118 > is under the ir u- ence of a restoring spring in similar manner. As can be seen from Figure 17, the driving lever 123 is provided with a bend c at the side facing the control arm 127. The control arm 127 is so arranged that when it rotates in the direction of the arrow, it has passed the bend c when themotor is switched off, so that the restoring springs 132 return to the initial position the knife levers and at the same time the driving levers; 123, 124, the control shaft 121 and all the control arms mounted thereon. The locking pin 136 arranged in the bearing 109 is so arrangedi and the cup 134 so offset in the peripheral sense in the gear wheel

110 that, after the twisting device is uncoupled by the dog clutch 52, '53,' the pin 13i6 automatically centres the twisting wheel 110 accurately so that the slot 12.8 of the twisting pinion 112. faces the front, as is necessary for inserting the steel wires before thqr are twisted and for extracting same after they have been twisted. 10 course, instead of this centering means it would also be possible to use another pFer se known centering means e.g. spring pawls of known type. The machine can then be pulled' off backwards by hand, the wire loop being withdrawn from the twisting pinion 112, the bearings 113, 114 and the 'guide elements 115, 11.6.. The constructional form according to Figures 20 and 21 differs from the preceding constructional form merely in that a bearing arm 141, whose free end comprises a fork, is secured to the gear casing 6. A ,two-armed control lever 1431 is mounted in the said fork 'by means. of a bearing pin 142. 'Said control lever is articulated at each end, releasably at one end, to one of the two hand levers 75, 81 respectively. For this purpose both the control lever 75 and also the control lever t81 are provided with a hole which carried a pin 144 in the case of the control lever 75 and 145 in the case of the control. lever 8'1, and the other end of each pin being inserted in an appropriate hole in the lever 143. Roth pins ar preferably inserted in the ,said lever in such manner as to be capable of being withdrawn therefrom. The control clutch halves 29, 52 are coupled in opposed relationship to one an other by means of this control lever, i.e. when, in order to start the machine operating, the dog clutch 29, 30 is engaged by operas ing the lever 751 by hand, the control lever 143 actuates the hand lever 81 positively in the sense of disengagement of the dog clutch 52, 53. Vice versa, after the tensioning oper ation is concluded, as soon as the dog clutch 29, 301 is automatically disengaged and there fore the clutch coupling sleeve 2,7 is disr engaged in the sense of the arrow 146 (Figure 2;1), then the ,control sleeve 50 of the other, dog clutch is positively engaged in the direc tion of the arrow 147 and the closing opera tion initiated thereby. In this condition the machine is employed for series packing work, 'when the requisite tension of wire loop is fixed once for all for a whole series lof ,packs.. However, if it is desired to change over to another series, in

which the requisite tensioning force must first be tested, then one ,of the pins 144, 145, or if necessary both these pins, b withdrawn from the control lever 143 and the relevant hole in the hand luver. This eliminates the automatic contranpsense connection of the dog clutches. Then, if necessary, subsequent tensioning can be carried out by changing one or more times the tension of the slipping clutch spring, until a suitable wire tension has been found, whereupon the pin or pins 144 or 145 can be re-inserted in position so as to re-establish the arrangement for automatically engaging and disengaging the dog clutches. Of course this or a similarly operating auto matc apparatus can also be used in the case of the analogous embodiment of a band tension ing machine such as was described, e.g. with reference to Figures 1 to 12, hereinbefore. The same applies analogously to the sever ing mechanism which was described with reference to the embodiment shown in Figures 16 to 19. It is advantageous to combine with the means for varying the pre-tension of the dutch spring 22 as 'described with reference to Figure 118, an indicating device for allowing the particularly preension force of the clutch spring to be ascertained at any time.. To this end, one of the radial support arms 138 of the spring cap 137 can be provided with a pointer marking which coWoperates with a scale provided on the wall of the clutch housing 1.8. The scale can indicate the p rticular pre tension of the clutch spring indirectly, e.g. in kilograms, or alternatively directly, namely with relation to the maximum tractive force capable of being transmitted ;by the tension ing wheel to the packing wire at the particu marly pre-tension of the clutch spring. Thus lin: this case the device indicates, at each posi tion of the spring cap, the tensioning force which the machine is capable of transmitting to the pack in this condition. This device

also can easily be used analogously where a band is being used as a tensioning member instead of a wire. What we claim is: - 1. A motor-driven machine for tensioning and closing a loop applied about a pack, com prising a tensioning device which is adapted to tighten the loop, a closing device which is adapted to connect the loop ends to one an other, and a motor which drives the tension ing device by way of a slipping clutch and which also drives the closing device, the ten sioning device being stopped automatically after a loop tension .determined by the force transmitting capacity of the slipping clutch is reached, 'wherein the tensioning device and the closing device are each 'driven by way of a control clutch operable to complete the drive. 2. A machine according to claim 1, wherein the control clutch of the tensioning device is automatically: disengaged by the slipping of the slipping clutch. 3 A machine according to claim 1, wherein the control clutch of the tensioning device is arranged between the slipping clutch and the tensioning device. 4.. A machine according to claim 2, wherein the slipping clutch comprises two concentric clutch halves which are provided with Co- operating helical gear teeth, Sone of these clutch halves being axially displaceable, aud whereof the axially displaceable clutch half is connected to a displaceable clutch half of the control clutch of the tensioning device. 5 A machine according to claim 4, wherein the axially displaceable clutch half of the slip ping dutch is mounted on a hollow shaft so as to be axially displaceable thereon and is rigidly connected to a control rod which is longitudinally dispIaceable in this hollow shaft and on whose other end is mounted the mov able control clutch half which is longitudinally displaceably mounted on the hollow shaft, the hollow shaft being provided with apertures

for parts adapted to connect the control rod to the aforesaid displaceably mounted clutch halves, and the other clutch halves of these two clutches are rotatably mounted on the hollow shaft. '6. A machine according to claim 5, where in the parts adapted to connect the control rod; to the dispinceably mounted clutch halves are pins which each extend through the rod and one of these clutch halves, and the aper tures of the hollow shaft are constructed as slots whose longitudinal axis is directed axially with respect to the hollow shaft 7. A machine according to claim 1 or 2, wherein the slipping clutch is provided with an axially displaceable clutch half which, to gether with a clutch spring therefor, is arranged in a cylindrical housing which is closed by a cover forming the other clutch half and is rotatably mounted on the hollow shaft and is in engagement with the motor drive. 8. A machine according to any of claims 1-7, wherein the slipping clutch is provided with a clutch spring and a device for varying the pre-tension of the clutch spring. 9. A machine according to claim 7 or 8 wherein one end of the clutch spring bears against a spring cup which is guided so as to be axially displaceable in a housing for the clutch and which is provided externally with radial support arms which each project through a slot in the housing wall and are supported on an adjusting nut which is adjustablty screwed on to an external thread on the housing wall. 10. A machine according to any of claims 1-9, wherein the control clutch of the clos- ing device is adapted to be controlled optionally either by hand or positively and in opposite senses by the control clutch of the tensioning device. 11 A machine according to any of claims 1-10, wherein the control clutches are dog clutches. 12. A machine according to claim 11 as dependent on any of claims 4-6, wherein the axially displaceable clutch halves of the two control clutches are each adapted to be engaged and disengaged by means of a swingable hand lever. 13. A machine according to claim 10 as dependent on any of claims 4-6, wherein the axially displaceable control clutch halves of the control clutches are releasably connected to one another with interposition of

a two-armed pivotably mounted control lever. 14. A machine according to claim 13, wherein the control lever is connected at each end, and releasably at at least one end, to one of the two swingable hand levers. 15. A machine according to claim S or 6, wherein the tensioning device comprises a tensioning wheel which is mounted so as to be freely rotatable and non-displaceable axially on the hollow shaft and which at the same time forms the non-'displaceable half of the control clutch for the tensioning device. 16. A machine according to any of claims 1-15, wherein the loop is formed of wire and the closing device comprises a twisting pinion for twisting together the ends of the loop, and the twisting pinion is in engagement with a toothed wheel which is mounted on an intermediate shaft driven by way of the control clutch of the closing device, the said intermediate shaft comprising a control arm which co-operates with a pivotally mounted driving lever for a cutting mechanism intended for severing the superfluous loop end portions, in such manner that the cutting mechanism is actuated automatically after the twisting operation has been completed. 17. A machine according to claim 16, wherein the cutting mechanism comprises two pivotally mounted knif.e levers which are arranged' at a distance from one another cor