4306 4310.output
Transcript of 4306 4310.output
* GB784713 (A)
Description: GB784713 (A) ? 1957-10-16
Improvements in fire-alarms for combustible material
Description of GB784713 (A)
PATENT SPECIFICATION
Go Date of filing Complete Specification July 12, 1955.
Application Date July 14, 1954.
Complete Specification Published Oct 16, 19570
Index at Acceptance:-Class 118 ( 1), D( 1: 4).
International Classification: -GO 8 d.
COMPLETE SPECIFICATION
Improvements in Fire-Alarmn for Combustible Material We, THE BRITISH
CECA COMPANY LIMITED, a British Joint Stock Company, and JOHN RONALD
FOXCROFT, a British subject, both of 175, Piccadilly, London, W l, 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 fire-alarm apparatus for detecting incipient
combustion in a stack or layer of granulated combustible material
exposed to air or other gas containing oxygen The combustible material
may be, for example) ian adsorbent carbon, Catering charcoal or
granulated carbon having a catalyst deposited thereon.
Combustion detectors or fire-alarms for this purpose generally
comprise a number of ternperature-sensitive elements or tappings
distributed in the combustible material, for ex ample electrical
elements of resistance varying with the temperature; these detectors
generally involve delicate and expensive apparatus.
Fire-alarm systems are also known comprising one or more pipe lines
containing fluid which is maintained at a pressure different from that
of the atmosphere by a pump, each of said pipe lines being fitted with
one or more fusible plugs by which the pipe is vented to the
atmosphere automatically when the temperature rises above a preset
limit, the said pipe or pipes being connected to one or more pressure
actuated devices by which an alarm is given when a change of pressure
occurs in the pipe line owing to the opening of one or more of the
fusible plugs.
The present invention consists essentially of an alarm comprising at
least one continuous detector tube, made of fusible or thermally
plastic material, to be arranged in the combustible material, means
for connecting one end of the tube to a source of fluid pressure, and
means for connecting the other end of the tube to a device sensitive
to said pressure and adapted to control an alarm signal, normally
holding it out of operation, in such a way that melting or softening
of the detector tube due lPnu.
to rise of temperature of the combustible material will reduce the
pressure in the tube 50 and cause the operation of the alarm signal.
When spontaneous combustion or ignition occurs in the combustible
material, combustion is maintained by the air traversing this
material, and an incipient fire is created which 55 is liable to
spread gradually through the material When the heat reaches the
vicinity of a detector tube, the rise of temperature immediately or
very soon causes the melting or softening of the fusible or plastic
tube where 60 by the pressure therein is reduced, so that the alarm
signal operates.
One er more detector tubes may be provided, and the tube or each tube
may have the shape of a sinuous line with numerous bends 65 to and fro
within the combustible material.
The invention is hereinafter described with reference to the
accompanying drawing, which illustrates diagrammatically an embodiment
comprising two detector tubes a, b, arranged 70 in parallel and both
connected at one end by way of a pipe c fitted with a pressure gauge
d, safety valve e and reducing valve f, to a single source of gas
under pressure at g, and connected at the other end by way of a second
75 pipe k fitted with a pressure gauge i to a single alarm-control
device j This device consists of a pressure switch in the form of a
bellows normally holding down a counterweighted contact arm k so as to
keep open a pair of 80 contacts t in an electric circuit m energized
by a mains supply at N and including the winding o of an audible alarm
such as a bell p.
If it is desired to supervise a stack of combustible material
comprising several beds or 85 layers q, as shown, each tube a, b may
control two or more beds or layers connected in series.
Each tube has preferably the shape of a sinuous line with numerous
bends to and fro within the combustible material, as shown, the 90
parts of the tube being sufficiently close together for melting or
softening to occur at some point thereof after a fairly short time of
heating.
A system of valves r may be provided for 90 isolating the several
tubes; when the alarm 704,713 No 20561/54.
784,713 signal is operated, due to melting of a tube a or b at any
point and resulting closure of the contacts 1, it will then be
possible by closing the several valves r so as to isolate the tubes a,
b in turn, to identify the tube wvhich has melted and thereby to
determine the precise situation of the incipient fire For example, if
the closing of the two valves r on the right, which isolate the tube
a, does not stop the alarm, then the failure must be in the other
detector tube b Where each tube controls two beds or layers, as in the
embodiment illustrated, a third valve S may be interposed in each tube
between the two beds or layers, which will allow a further
determination of the particular bed or layer in which the incipient
fire is located.
In another arrangement, each bed or layer may be provided with a
separate detector tube, or again each tube may control a given zone of
one and the same layer covering a large area, the several tubes being
connected in parallel and fed from the same source of pressure.
The alarm may be tested from time to time by means of a test cock t
which will allow the fluid pressure to escape from near the control
device j The pressure gauges d and i will show at all times whether
equal pressure is maintained throughout the apparatus and the latter
is in proper condition for operation; any difference between the
readings of the two pressure gauges will indicate that leakage is
taking place, due for ex ample to a small local failure of a detector
tube.
The detector tubes a, b may be made of lead or of another metal or an
alloy melting at relatively low temperature, or they may be made of
plastic material, such as nylon or polyvinyl chloride, which softens
sufficiently under relatively low heating to reduce the fluid pressure
just as with the melting of the fusible tubes.
The gas employed is preferably inert as regards combustion, for
example nitrogen, but in some cases the tubes may be connected by way
of the pipe c to a compressed air line under constant pressure, where
the use of an inert gas is not considered necessary.
Where several beds cr layers of combustible 50 material are providerd
with separate detector tubes, each bed will have its own alarm control
device, each bed being thus self-contained; in addition to controlling
the audible alarm, common to all the beds or layers, each control 55
device may cause the lighting of an individual warring lamp to
indicate which bed or layer has developed the excessive rise of
temperature.
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* GB784714 (A)
Description: GB784714 (A) ? 1957-10-16
Improvements in or relating to spark gap arrangements
Description of GB784714 (A)
PATENT SPECIFICATION
Inventor: HORACE FREDERICK JONES 784,714 Date of filing Complete
Specification Aug 30, 1955.
Application Date Aug 6, 1954.
Complete Specification Published Oct 16, 1957.
No 22947/54.
Index at Acceptance:-Classes 22, J( 2: 17: 28); and 39 ( 1), D( 8: 12
86: 38).
International Classification: -C 04 b H 01 j.
COMPLETE SPECIFICATION
Improvements in or relating to Spark Gap Arrangements We, THE GENERAL
ELECTRIC COMPANY LIMITED, of Magnet House, I Kingsway, London, W C 2,
a British 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 spark gap arrangemenrits for use in electric
surge diverters Electric surge diverters take a number of forms and in
one known form, a plurality of metal electrodes are spaced apart in a
stack, the gaps between the electrodes being defined by spacers of
insulating material The usual material used for this purpose is
steatite and one object of the present invention is the provision of a
spark gap arrangement which shows great advantage over the known
arrangements.
According to the present invention, a spark gap arrangement for a
surge diverter includes at least a pair of metal electrodes spaced
apart or separated by a spacer or member of insulating material of
high permittivity compared with steatite.
One particularly suitable material is bariumor
barium-strontium-titanate with a small addition of zinc titanate and
spacers of either of these materials may be made up in the form of
flat rings, the rings being disposed in a stack and separating a
plurality of circular plate-like brass electrodes.
In order that the invention may be clearly understood, one
construction of a multi-spark gap arrangement of a surge diverter and
in accordance with the invention will now be described by way of
example with reference to Figures 1, 2 and 3 of the accompanying
drawings in which Figure 1 shows a side view partly in section of the
arrangement, Figure 2 shows a side view of a spacer and Figure 3 shows
a top plan view of a spacer Figure 4 shows a side view, in section, of
a modification having inserts to improve the impulse sparkover ratio
of the arrangement.
lNce 3 s 6 d l Referring now to Figures 1, 2 and 3, the multi-spark
gap arrangement comprises a plurality say, eighteen, circular
plate-like brass electrodes 1 ail of identical form and pressed 50 on
one side with one or more protuberances 2 arranged to act as sparking
regions Except for the two electrodes 1 at the two ends of the stack,
the electrodes are grouped in pairs back to back with the
protuberances 2 direc 55 ted outwardly, and the protuberances of the
end electrodes are directed inwardly, that is, towards the
protuberances of the adjacent electrode 1 Between the adjacent pairs
of electrodes 1 and between the end pairs and the 60 single end
electrodes 1 are disposed spacers 3 of insulating material of high
permittivity and these spacers are in the form of flat rings or short
hollow cylindrical annuli of outer diameter equal to the diameter of
the electrodes 65 1 The end faces of the spacers are ground flat and
conform with the adjacent electrode surfaces and in order to malke
good electrical contact with the metal electrodes, the end faces are
silvered This silvering may be effected 70 either by firing on a
silver paste of known type or by metal spraying, and the inner and
outer peripheral surfaces, the curved surfaces, of the rings are
protected against surface tracking by coating with a good
anti-tracking glaze 75 or varnish.
One composition of spacer found suitable in an experiment had the
composition 9 99 mole (Ba, Sr) Tio, 01 mole Zn Tio,, the ratio of
barium to strontium being 65:35 This 80 composition was made up by
using quantities of barium carbonate, strontium carbonate, titanium
oxide and zinc oxide in the following specimen amounts:Ba CO, 1270 g
85 Sr CO, 511 4 g.
Ti O 2 791 8 g.
Zn O 0 814 g.
and the constituents were milled together under water, filtered, dried
and sieved, pressed 90 into blocks with a suitable binder and fired in
an electric furnace After firing, the blocks2 784,714 were crushed,
milled dry and then -wet, filtered and dried again, mixed with a small
amount of camphor as a binder and pressed into spacers of the desired
size The pressed spacers were then fired with or without a glaze on
the curved surfaces and finally given surface grinding on their flat
end faces.
Spacers formed by the method and of the composition described above
have a peak permittivity of the order of 12000 at 12 C and a
permittivity greater than 3000 over the temperature range minus 20 C
to plus 45 ' C.
This value is high compared with that of steatite usually used which
is of the order of 6 and where the expressions "material of high
permittivity compared with steatite" and "material of high
permittivity" are used in this specification and its claims, a
material is meant whose permittivity is measured in hundreds or
thousands rather than in units or tens as is steatite The power factor
of the spacers is of the order of 0 01 at 255 C rising to a peak at G
C, the d c resistance at 500 V greater than 1000 megohms for a spacer
a" thick, about 2 " external diameter and 15 " internal diameter, and
the breakdown voltage for such a spacer about 7 k V.
Spacers of the nature described above are very effective in reducing
the impulse sparkover voltage and in improving the operating
consistency of surge diverter spark gaps The relation of spark-over
voltage to the number of gaps is practically linear for both power
frequency and impulse voltages and the effect of impulse polarity on
the spacers appears to be negligible Spark gap arrangements according
to the present invention may be mounted in air nitrogen or other
suitable inert gas and may be housed in standard sealed containers and
in series with non-linear resistors in known manner, the spacers of
high permittivity associated with each spark gap in air, nitrogen or
other suitable inert gas producing intense loca' ionisation when a
voltage approaching the breakdown value is applied Due to the high
capacitance of each section, the voltage grading on the ordinary 50
cycle power frequency supply is better than with known spark gap
arrangements using steatite spacers.
Referring now to Figure 4 which shows the modified construction and in
which the same reference numerals have been used for those parts
similar to parts in Figures 1, 2 and 3, the electrodes 1 are again
provided with protuberances 2 and separated by spacers 3 of high
permittivity In order, however, to improve the impulse spark-over
ratio of thed arrangement, with each gap is associated a Tsection
cylindrical insert 4 of material similar 60 to that used for the
spacers 3, each insert 4 being a press fit in an aperture 5 in one
electrode 1 of a pair of electrod:s of a gap and there being a small
gap between the end of the insert and the other electrode of the rair
Each 65 insert acts as a pre-ionising member upon the gap being
subjected to ar over-voltage, to facilitate breakdow-n of the gap and
thereby to improve the impulse spark-over ratio of the complete
arrangement 70
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* GB784715 (A)
Description: GB784715 (A) ? 1957-10-16
Churn
Description of GB784715 (A)
COMPLETE SPECIFICATION
Churn
We, LA CIA J. A. GOSSELIN LIMITeES of Drummondville, Province of
Quebec, Canada, a Canadian 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 :-
The present invention relates to machinery for making butter and more
particularly to a combined churn and butter worker.
The general object of the present invention is the provision of a
combined churn and butter worker having novel means for access within
the churn drum, improved means for maintaining suitable temperatures
for the cream during the churning operation and for the butter during
the working operation, and novel means for thoroughly washing the
butter in the drum or the churn itself when empty.
A more specific object of the present invention is the provision in
acombined churn and butter worker of means, easily operable from an
exteriorly controlled valve, which will alternately circulate water in
the drum beaters in order to maintain the temperature of the cream or
butter at the most suitable tempera- ture for efficient churning and
working, and inject water directly into the drum so as to thoroughly
wash the same when empty or to wash the butter contained therein free
from the buttermilk prior to working.
An important object of the present invention is the provision of a
butter churn and worker in which the drum has a cylindrical shape and
is supported only from one end thereof while its outer end is provided
with a central circular manhole for easy access into the interior of
said drum whatever be the angular position of the same.
Still another important object of the present invention is the
provision in a combined churn and butter worker of an improved drain
valve for drawing off the buttermilk and wash water after the churning
operation while retaining the butter in the churn drum, said drain
valve being easily and quickly removable from the drum for cleaning,
repairs or other purposes.
Still another important object of the present invention is the
provision of an improved air vent for the drum of a combined churn and
butter worker of the type described.
Yet another important object of the present invention is the provision
of a drum for a butter churn which is constructed of metal and
provided with beaters so designed as to renforce said drum.
Yet another important object of the present invention is the provision
of a combined churn and butter worker which will give a prolonge and
trouble-free service.
The present invention also relates to a leakproof closure for butter
churns and the like.
Doors for hermetically closing drums or other receptacles under
pressure, and more particularly butter churns, are provided with a
complicated mechanism in which a plurality of wheels or levers have to
be rotated for opening or closing the door.
The operation of this mechanism is time consuming especially in
connection with a butter churn which has to be opened and closed
several times during one churning operation.
Accordingly, a further object of the present invention is the
provision of a drum door and clamping ring therefor which will obviate
the above mentioned defect.
Another important object of the present invention is the provision of
a drum closure of the character described which is readily and easily
opened or closed.
Yet another important object of the present invention is the provision
of a door closure of the character described which will be completely
leakproof for both liquid and gases and in which a uniform pressure
will be applied on the entiro periphery of the door.
Still another Important object of the present invention is the
provision of a drum closure of the character described which is
relatively simple and inexpensive to manufacture and will give a
prolonge service.
The foregoing and other important objects of the present invention
will become more apparent during the following disclosure and by
referring to the accompanying drawings in which :-
Figure 1 is a perspective rear end view of the churn according to the
invention.
Figure 2 is a side view mainly in longitudinal section of the same.
Figure 3 is a broken fractional longitudinal section of the same.
Figure 4 is a fractienal elevation of the rear end wall of the churn
drum showing the beaters in cross-section.
Figure 5 is a section along line 5-5 of
Figure 4.
Figure 6 is a longitudinal section of the drain valve of the churn
drum.
Figure 7 is a perspective view of said drain valve about to be removed
from the churn drum.
Figure 8 is a perspective view of the drain valve plug and filter in
disengaged position.
Figure 9 is a fractional elevation of the same elements in assembled
position.
Figure 10 is a fractional sectional view of a bayonet joint used for
securing the filter to the drain valve plug.
Figure 11 is a sectional elevation of the air vent provided for the
churn drum.
Figure 12 is a view at right angles of the e same.
Figure 13 is a longitudinal section of the thermometer assembly
provided in the churn drum.
Figure 14 is a view at right angles of the same.
Figure 15 is an elevation of the drum closure according to the
invention in closed position.
Figure 16 is a cross-section along line
16-16 of Figure 15.
Figure 17 is a detailed cross-section of the door assembly showing the
clamping ring in non-clamping position.
Figure 18 is a cross-section similar to that of Figure 17 showing the
ring in clamping position.
Figure 19 is a partial longitudinal section of the door assembly
showing the clamping ring in non-clamping position; and
Figure 20 is a section similar to that of
Figure 19 showing the ring in clamping position.
Referring now more particularly to the drawings in which like
reference characters indicate like elements throughout, the numeral 1
denotes a base of substantially rectangular cross-section supporting
and forming a housing for the driving mechanism of the churn. The rear
face 2 of the base 1 is provided with an opening normally closed by a
removable closure 3. The base 1 is surmounted by a hood 4 which is
also removable.
Said base supports an interior frame 5, shown more particularly in
Figure 2, by means of corner bracket 11 and bolts 5'. A heavy duty
bearing 7, the axis of which is horizontal, is mounted on the frame 5
and projects through the front 6 of the base 1. The frame 5 is
provided with a rearwardly extending yoke portion 8 passing through a
rear opening 9 of the hood 4 and terminated by a vertical ring 10
coaxial with the bearing 7. A rearwardly extending hood 12 is rigidly
supported by the ring 10 to which is secured, by means of a bolt 13,
an inner projection 11 of said hood.
The front portion of the hood 12 engages the opening 9 of the hood 4.
A cover 14 and flanged bushing 15 are rigidly secured to the ring 10
by means of bolts 16. The ring 10 and bushing 15 support a ball
bearing 17 as shown in Figure 3.
A hollow, horizontally disposed shaft 18 is journalled in bearings 7
and 17. Said shaft 18 has a tapering rear end portion 19 abutting
against the ball bearing 17 and is provided with an inner cylindrical
tubular extension 20 rigidly secured thereto and journalled in the
ball bearing 17. The hollow shaft 18 has an intermediate portion 21 of
conical shape which increases in diameter towards its front end, and a
cylindrical portion 22 journalled in the bearing 7 and termmated at
its front end by an outward radial flange 23.
The churn drum, generally indicated at 24, is made of metal and has a
cylindrical shape.
Its rear end wall 25 is slightly concave and is secured to the flange
23 of the hollow shaft 18 by means of bolts and nuts 26 in such a
manner that the drum 24 will be coaxial with the shaft 18.
The front end wall 27 is also slightly concave and is provided with a
central circular manhole 28 which may be closed by a quick acting
hermetic closure 29 which will be more particularly described
hereinafter with reference to Figures 15 te 20 inclusive.
From the above described arrangement, it is seen that the churn drum
24 is totally supported from its rear end by the shaft 18 and that the
front end thereof is completely free of obstructions, whereby very
easy access is provided to the interior of the drum through the
manhole 28.
In order to firmly support the drum 24 and its load, the base 1 is
provided with forwardly extending integral legs 30 terminating
underneath and at the sides of the drum 24 opposite the middle portion
thereof.
The shaft 18 and drum 24 are rotatively driven by means of the
electric motor 31, shown in Figure 2, mounted in the bottom ot the
base 1 and dring the pulley 32 by means of the endless belt 33. The
pulley 32 is keyed to a shaft 34 journalled in the bottom portion of
the frame 5. A pinion 36 is keyed to the shaft 34 and meshes with a
gear 37 rigidly secured by bolts 39 to a flange 38 upon the conical
portion 21 of the shaft 18. The bottom portion of the frame 5 forms an
oil pan 40 into which dips the pinion 36. Thus said pinion 36 and gear
37 are well oiled at all times. An eccentric oil pump 41 is also
mounted on the shaft 34 and feeds oil under pressure to the bearing 7
by means of pipe 42. Return of the oil is made through the drain pipe
43. As it is very important that the bearing 7 be kept lubricated at
all times, a gauge 45 is mounted on top of the bearing 7 to provide an
indication of the oil pressure within said bearing.
A switch, not shown, is mounted at a suitable location in front of the
drum 24 to control the electric motor 31 in order to stop and start
rotation of said drum.
Refrring to Figures 2,4 and 5, the drum 24 is provided with inner
beaters 50 longitudinally extending in adjacent spaced relationship to
the cylindrical wall 51 of said drum.
Each beater 50 has a substantially rectangular cross-section with a
bevelled outer longitudinal edge 53 and is mounted so that its side
walls 54 extend radially of the drum 24.
The front end of each beater 50 is directly secured to the front end
wall 27. The beaters 50 are hollow and provided with a longitudinally
extending middle partition 55 defining an outer chamber 56 and an
inner chamber 57 in communication with each other at the front end of
said beaters 50 as shown at 58. The rear end of the beaters 50 is
closed by and rigidly secured to radially extending conduits 59 of
substantially trapezoidal cross-section and having side flanges 60
rigidly secured to the rear end wall 25 of the drum 24. The conduits
59 converge toward the center of the circular end wall and are in
communication with each other.
Alternate beaters 50 are provided at their front end with a triangular
reinforcing member 61 secured to the inner edge of said beaters and to
the front end wall 27 of the drum 24. The remaining beaters 50 are
similarly provided with triangula reinforcing members 62 secured to
the rear end wall 25 of the drum 24.
The churn, according to the invention, is provided with means to
circulate water through the beaters 50 and to inject cleaning or
washing water directly into the drum 24.
These means will be described presently.
Referring to Figure 3, a return pipe 70 extends through the whole
length of the hollow shaft 18 and its forward end threadily engages a
sleeve 71 welded to the rear end wall 25 of the drum 24. The rear
portion of the return pipe 70 is centered within the hollow shaft 18
by means of a collar 72 engag- ing the inner face of the rear end of
the tubular extension 20. The rear end of the return pipe 70 projects
from the cover 14 and is provided-with inner threads 73 to engage the
threaded shank 74 of a hand wheel 75.
Moreover, the return pipe 70 is provided with a series of radial
discharge openings 77 in alignment with an annular groove 78 made in
the cover 14.
A nipple 79 is aligned with the forward end of the return pipe 70 ; it
is secured to the sleeve 71 and extends through the converging ends of
the conduits 59 which are covered by a disk 80.
The nipple 79 is provided with a first series of radial openings 81 in
communication with each conduit 59, and with a second series of radial
openings 82, each in communication with a pipe 83 extending in each of
the conduits 59 and discharging into the outer chamber 56 of each
beater 50 through an opening 84. The inner chamber 57 of each beater
communicates with a conduit 59 through an opening 63.
A feed pipe 85 extends within the return pipe 70 and is coaxial
therewith. The forward end of the feed pipe 85 is provided with a
valve member 86 having an axially bored piston-like portion 87 in
slidable contact with the inner face of the return pipe 70 inter-
mediate the two series of openings 81 and 82.
A transverse bore 88 is made in the valve member 86 forwardly of the
piston like portion 87 to establish communication between the inner
feed pipe 85 and the plurality of pipes 83 for feeding water to the
outer chambers 56 of the beaters 50. The front portion 89 of the valve
member 86 has a frusto-conical shape adapted to seat against the
bevelled forward end of the nipple 79 and close communication between
the feed pipe 85 and the interior of the drum 24.
The rear end of the feed pipe 85 is centered within the return pipe 70
by means of a spacer ring 90 and said feed pipe 85 is extended
rearwardly by means of an inner nipple 91 which is secured to it and
to the head 92 of a bolt 93 extending within the shank 74 of the hand
wheel 75. The bolt 93 is held against axial movement with respect to
the hand wheel 75.
Feed water is admitted to the churn by means of supply pipe 94
connected to an open- ing 95 made in the cover 14 and in communication
with the feed pipe 85 through the annular groove 96, the radial
openings 97 made in the return pipe 70 and the aligned radial openings
98 made in the nipple 91.
When the feed pipe 85 is in the position shown in full line in Figure
3, the water discharged therefrom passes through the transverse bore
88 of the valve member 86, the series of openings 82 and the pipes 83
to reach the outer chamber 56 of each beater 50. Said water will
return through the inner chamber 57, the conduits 59, the openings 81,
the return pipe 70 and finally through the series of openings 77 and
the annular groove 78 to be discharged to the exterior by pipe 100,
shown in Figure 1.
Upon rotation of the hand wheel 75 clockwise, the inner feed pipe 85
will be displaced forwardly and, consequently, the valve mem- ber 86
will assume the position shown in dot dash lines in Figure 3. In this
position, the piston-like portion 87 closes the openings 82 thereby
preventing water circulation through the beaters 50, and the feed
water is discharged directly into the churn drum 24.
The feed water is discharged into the drum while the latter is
rotating, thereby resulting in efficient cleaning of the drum or
washing of the butter.
Mixing of the ingoing and outgoing water is prevented by means of the
packing gland 101 disposed between the annular grooves 78 and 96 made
in the cover 14, while escape of the circulating water to the exterior
is prevented by the packing glands 103 and 104 disposed on the outer
side of the said. grooves 78 and 96. Any water which may leak through
the packing gland 103 is collected within the internal annular groove
106 and discharged to the exterior through the opening 107 made in
cover 1. 4. Additional packing glands 108 and 1. 09 are also provided
to prevent water from reaching the ball bearing 17 and from leaking
around the hand wheel shank 74. The rear hood 12 is provided with a
bottom opening 110 for easy access to the hand wheel 75 and to the
connections of the pipes 94 and 100 to the cover 14.
The churn drum 24, according to the invention, is also provided with a
drain valve, generally indicated at 105 in Figure 1, and more
particularly shown in Figures 6 to 10 of the drawings. Part of the
rear snd wall 25 and cylindrical wall 51 is cut off at their junc-
tion and a cylindrical sleeve 111 is inserted in the cut off portion
of said walls and welded at 112 to the end wall 25 and at 113 to the
cylindrical wall 51. The sleeve 111 is completely cylindrical at its
inner end 114 and is slotted at 115 along its outer part. The inner
wall of the sleeve 111 defines an inner shoulder 116 and a bevelled
plug seat 117. Moreover, segmental lugs 118 project nwardly from said
sleeve 111 in spaced relationship with the shoulder 116.
A plug disk 119 is adapted to abut the seat 117 for tightly closing
the drum 24. A thrust plate 120 is adapted to removably engage the
space between the lugs 118 and the shoulder 116 and supports an
inwardly threaded sleeve 121 which receives an operating screw 122
provided at its outer end with an int gra' knob 1221 and abutting the
plug 119 at it" inner end.
The operating screw 122 is rof-afbly mounted and encloses a spindle
123"'eldsd at its inner end to the plug 1195 as sko vn at 124 and
threadily receives at its outer end a bolt 125 retaining a washer 126
to prevent disengagement of the operating screw 122 from said spindle
123.
A wire mesh, or preferably a perforated metal cylindrical filter
screen 127, open at one "end, is inserted within the drum 24 and is
removably secured to the inner face of the plug 119 by means of two
diametrically oppsed longitudinally extending fingers 128 welded to
the annular band 129 secured to one end of the cylindrical screen 127.
The fingers 128 have a groove 130 at their outer end adapted to
removably engage the bayonet slots 131 made in the inner face of the
plug 119
Two additional spacer fingers 132 also diametrically opposed are
secured to the band 129 and are adapted to abut against the inner face
of the plug 119.
The operation of the drain valve described is as follows: To drain the
wash water or the buttermilk from the drum, while retaining the butter
clots therein, the knob 1221 is rotated and displaces the plug 119 and
screen 127 outwardly. The wash water or buttermilk will flow through
the screen 127 and will be discharged to the exterior through the slit
115.
To remove the entire drain valve unit, the thrust olate 120 is rotated
to disengage the lugs 118. The screen 127 may be detached from the
plug 119 by a relative lateral displacement so that the fingers 128
may be disengaged from the bayou, et slots 131. The screen 127 may
then be cleaned, repaired or replaced.
The drum 24 of the churn, according to the invention, is also provided
with an air vent in order to allow the escape of gases which may be
formed within the drum during the churning operation. This air vent is
shown more particularly in Figures 11 and 12. It comprises a-cup
shaped member 133 welded around its periphery to the edge of a
circular hole made in the front wall 27 of the drum 24. This cup
shaped member 133 is provided at the center of its bottom wall 134
with a bevelled circular opening 135 and is normally closed by the
tapsred inner end 136 of the cylindrical valve member 137. Said valve
member 137 is slidabis in a sleeve 144 secured to the bottom wall 134,
and has at its outer end a cylindrical extension 138 of smaller
diameter than the body 137 grooved at its free end at 139 for
receiving a spring clin 140 retaining a hexa, onal cap 14141 vhich
abuts against the shoulder 142 and is provided with a cylindrical
flange 143 having inner threads engaging the outer threads of the
sleeve i44. Partial unscrewing of the cap 141 allows the gases to
escape through the discharge openings 145 made in the flange 143 of
the cap 141. This air vent is not automotic because it ha-ben found
that an automatically operated air vent is liable to open while in a
lower position during rotation of the drum 24 thereby dis charging
liquid as well as gases. This air vent is easily cleaned and may be
taken apart by removing the spring clip 140.
The butter churn according to the invention is provided with a
suitable thermometer to indicate the temperature of the materials
inside the churn drum 24. A dial thermometer- 146 (Figs. 13 and 14) of
the bi-metal type is mounted in a cup-shaped member 147 welded to the
edge of a circular hole made in the front end wall 27 oi the drum 24.
The shank 148 of the thermometer 146 is protected against damage by an
outer sleeve 149 closed at its outer end 150 and welded to the
cup-shaped member 147. In order to further protect the thermometer 146
against damage it is prefer- ably located adjacent a beater 50.
The interior surface of the metal drum 24 may be treated by any known
suitable process in order to prevent the butter from sticking to said
surfaces.
Referring now to Figs. 15 to 20, the access door or closure 29 for the
churn is lodged in a ring member 151 of substantially the same
internal diameter as the circular manhole 28 rigidly secured to the
outside face of the front end wall 27 and is co-axial with said
opening 28. The inner face of the ring member 151 is provided with a
V-shaped groove 152 for removably receiving an annular gasket 153 made
of rubber or the like elastic material and of circular cross-section
when released.
Adjacent the front end wall 27, the ring 151 is also provided with an
inwardly projecting rim 154 adapted to form an abutment for the
marginal portion of the door 29.
The door 29 is a flat disc preferably made of transparent
non-breakable material and is provided with a center knob or handle
155 rigidly secured thereto by a screw 156.
A slit clamping ring 157, preferably made of steel, is adapted to be
removably inserted against the inner surface of the rubber gasket 153.
The clamping ring 157 is provided near its free ends with the
respective brackets 158 and 159. A toggle lever 160 is pivoted at 161
to the bracket 158 and is provided at its outer free end with an
operating handle 162. A connecting rod 163 is pivoted on the bracket
159 at 164 and its threaded outer end engages a sleeve 165 pivoted on
the lever 160 on pivot 166 spaced from the pivot pin 161. Pivotal
movement of the toggle lever 160 towards the clamping ring 157 moves
the ends of the latter away from each other whereby said clamping ring
157 tightly engages the gasket 153 and compresses the same within the
groove 152 to deform said gasket and bring it in contact with the
outer marginal face of the door 29 as shown in Figure 18. In this
manner, a completely leakproof closure is obtained.
The clamping force exerted by the ring 157 is uniform over its entire
surface and may be adjusted by screwing or unscrewing the connecting
rod 163 into or away from the sleeve 165.
To open the churn or drum, it is only necessary to unclamp the ring
157 by inward movement of the lever 1. 62, whereby said clamping ring
157, the gasket 153 and the door 29 may be removed successively. The
reverse opera- tion s effected to close the churn or drum.
The complet closing or opening of the drum may thus be effected in a
very short time.
The drum closure, according to the invention is completely leakproof
and will remain so despite vibrations to which it might be subjected.
From the foregoing description it will be apparent that the churn,
according to the invention, possesses a number of advantages over
butter churns known in the art.
Due to the fact that the churn drum 24 is mounted on the shaft 18 only
through its rear end wall 25 and is completely fr. ee of obstruction
at the front portion thereof, the manhole 28 may be located in the
center of the front end wall 27 whereby said opening is always at the
same easily accessible level in any position of the drum 24. This
important because the operator must have access to the interior of the
drum several times during butter making.
Due to the fact that the beaters 50 are provided with a water
circulation, the mixture of butter and liquid inside the drum may be
kept at the most suitable temperature for churning or working ; for
example, during churning the temperature is maintained preferably at
between 57 and 58 F. while during the working operation, the
temperature is lowered to within the range of 52 to 54 F.
The churn according to the invention is also provided, as described
previously, with very simple means for injecting cleaning water
directly inside the drum in such a manner as to effect efficient
cleaning of the drum walls or of the butter inside the same. These
means consist of the valve member 86 which forms a cone-like water
spray inside the drum and which is operated by the hand wheel 75.
Because water circulation through the beaters 50 is cut off during the
cleaning operation, a maximum water pressure is available.
Care has been taken to design the beaters 50 and the conduits 59 so as
to reinforce the drum walls and thus achieve maximum strength.
Finally the drain valve 105 is considered an important and novel
arrangement ; it closes the drum efficiently and may be quickly opened
for filtering the mixture of materials in the drum or bodily removed
for completely draining the drum and for washing or changing the
filtering screen 127.
While a preferred embodiment according to the present invention has
been illustrated and described it is understood that various
modifications may be resorted to without departing from the spirit and
scope of the appended claims.
What we claim is :-
1. A churn comprising a cylindrical drum supported at one end only by
attachment to a coaxial shaft mounted substantially horizontally in
bearings in a base, the drum being equipped vrith beaters extending
lengthwise along its wall, and having a door at its other end.
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* GB784716 (A)
Description: GB784716 (A) ? 1957-10-16
Manually-operated lifting and transporting appliances
Description of GB784716 (A)
PATENT SPECIFICATION
Date of filing Complete Specification Dec 2, 1955.
Application Date Sept 20, 1954.
Complete Specification Published Oct 16, 1957.
784, 16 No 27116/54.
Index at Acceptance:-Class 108 ( 1), E 5.
International Classification: -162 bo COMPLETE SPECIFICATION
Manually-Operated Lifting and Transporting Appliances I, ALBERT HENRY
SMITH, a British Subject, of 2, Church Street, Burton Latimer,
Kettering, do hereby declare the invention, for which I pray, that a
patent may be granted to me, and the method by which it is to be
performed, to be particularly described in and by the following
statement:-
The present invention is concerned with appliances by means of which
articles can be engaged, lifted and transported by manual effort.
There are many articles which have to be moved from place to place
but, because of their bulk, their weight, their temperature, and so on
are awkward or difficult to handle.
Examples of such articles are foundry dies, castings, pipes, paving
stones, curbstones, and slabs, to mention a few only It is an object
of this invention to furnish convenient appliances for handling
articles of this character, which latter will hereinafter be included
generically in the term "slab ".
The appliance provided for this purpose by the present invention
comprises a main carrying frame with a pair of spaced clamping jaws
and at least one lever arm or handle for lifting the frame, one at
least of said jaws being mounted relatively to the frame so as to move
arcuately in response to the lifting operation of said lever arm or
handle and engage one side or end of a slab suchwise as to urge the
latter against the other jaw and suspend the slab from the appliance
between the said clamping jaws.
Various forms of this appliance have been devised, some of which will
be described and illustrated hereafter in this specification.
Thus, in one such form, the frame is wheeled at one end part and
furnished at this end part with an arm (representing the first jaw)
pivoted on said frame and carrying a propelling handle, whereby
downward pressure on this handle will, through the arm, urge the slab
against another jaw (the second jaw) at the other end part of the
frame.
In this arrangement the propelling handle may be hingedly mounted on
the arm and have a cross member for coupling the handle and arm for
downward swinging movement in unison about the pivot of the arm on the
50 frame The second jaw may be a transverse member depending from the
frame and pivotable on this frame about an axis at right angles to the
pivot axis of the first jaw or arm.
In a specific form incorporating the features 55 mentioned in the
preceding paragraph, the frame conveniently comprises a bar or tube
extending longitudinally and medially of the appliance, with the first
jaw or arm passing therethrough, the second jaw depending in 60
pivoted fashion from the leading end thereof, a pair of wheels
depending from the rear end thereof, and a foot piece at this rear end
to assist the rocking of the frame about the wheels by the propelling
handle 65 With the structure set forth immediately above, a slab will
be removed by placing the frame of the appliance around the same, and
then throwing over the operating handle and tilting the frame, so that
it can be wheeled 70 away Instead, however, the appliance may be such
as to provide for raising the frame by a handle at each end, this
action simultaneously producing a grip on the slab between the jaws In
such an arrangement the frame 75 is therefore provided with a lifting
handle at each end, and one of these may be pivoted to the frame and
carrying the arcuately-movable jaw.
In accordance with a further feature of the 80 invention the other of
said handles is adapted to be connected to said frame at variable
positions therealong by fastening means Moreover, this other handle
may be detachably secured to the fastening means 85 The frame may
further comprise a pair of parallel arms having a first lifting handle
pivoted thereto at one end, this handle in turn having the first and
pivotable jaw articulated thereto, and said arms slidably carrying a
90 bracket which is adapted to be secured at a variable position along
these arms and carries the second jaw and a sleeve for attachment of
said other handle.
784,716 In another and simpler form embodying this principle of
lifting by means of handles at each end of the frame and
simultaneously imparting clamping pressure between the jaws, the
"first" jaw may be rigidly connected to one of the handles and the
other jaw affixed to the frame.
If desired the width of the frame may be adjustable to cater for
different widths of slab.
Form of lifting appliance constructed in accordance with the invention
are illustrated by way of example in the accompanying drawings, in
which:Figure 1 is a side view of a first form of the appliance, with
parts seen in cross-section on the line I-I of Figure 2.
Figure 2 is a plan view of the structure illustrated in Figure 1.
Figure 3 shows a second embodiment in side view.
Figure 4 is a plan view of the appliance of Figure 3.
Figure 5 is a cross section on the line IVIV, seen in the direction of
the arrows.
Figure 6 is a side view of a third embodiment and Figure 7 is a plan
view of this third embodiment.
The mechanism illustrated in Figures 1 and 2 is intended more
particularly for lifting and transporting large solid objects, such as
the slab 1 illustrated, but as will clearly be evident, can be used
for similar handling of various other forms of body which are heavy,
bulky or otherwise difficult to transport.
In this case the appliance comprises a central spine 2 which is in the
form of a steel tube slotted at 3 towards one end and having depending
therefrom, at this end, brackets 4 carrying a shaft 5 with wheels 6 at
its outer ends.
At its opposite end the steel rube has a spindle 7 passing loosely
therethrough and welded at its lower end to an angled cross bar 8, the
inner limb of which is provided with a pair of spaced pads 9 together
constituting one of the clamping jaws of the app D Dliance.
Passing through the slot 3 and pivoted by a cross pin 10 therein is an
arm 11 vwhich, towards its upper end is provided with a cross bar 12
extending to either side of the arm and having, at its ends, lugs 13
receiving pivot pins 14 by means of which a pair of propelling arms 15
is articulated to the cross bar 12 The arms 15 extend rearwardvly of
the appliance and together form a propulsion and lifting handle, being
joined towards their outer ends by a cross rod 16 and, towards their
leading ends, by a further cross red 17.
In use, the trolley-like appliance described is moved over the slabs 1
to be lifted and manoeuvred to bring the jaw pads 9 against the
leading edge thereof The handle arms 15 are then swung downwards and,
after the cross rod 17 has abutted the upper end of the arm 11, the
handle and this arn are coupled together to swing as a unit, thiereby
to bring the nose 13 of the arn, which nose forms the "first" clamping
jaw referred to above, against 70 the coposite end of the slab 1 Zter
this position has been reached, any further pressure exerted
do-wnwardis on the outer ends of the handle arms 15 increases thie
grin, et-ween the clamping jaws 9 and 18 75 To transport the article
gripred in this way, the spine 2 is swung up at an angle about the
wheels 6, thie dowrnrd pressure on the arms 15, for this purpose being
assisted by foot pressure on the foot piece 19, which is 80 secured to
the rear end of the spine 2 The slab can therefore be vwheeled away in
the appliance, the downward pressure on the handle 15 to keen the
snine raised ensuring that a tight clamping grip is applied by the 85
jaw 18 against the slab.
As will quickly be appreciated, the actual form of the structure
described can be modified in various ways, whfilst still retaining the
essential features of the device Thus, for 90 example, the centre
spine might be adjustabl-e in length, may be upwardly inclined,
cranked or bowed, so as to acconmmodate a taller article than the slab
illustrated, the forms of the jaws used may be modified to suit
differently-shaved 95 articles and so on As regards the last cf tlese
modifications, it is pointed out that these jaws might, for exampnle,
be curved for the purpose of icking up Trums, cylinderso pines and
like circular articles 100 The appliance illustrated in Figures 3 to 5
is suitable for picking up and transporting narrow articles such as a
curbstone 20, but again this is only an example of the type of body
with which it cwn deal, whether in the 105 formi showvn or modified.
In this instance the frame of the device comprises a pair of parailel
spaced tubzs 21 which are connected at both ends by cro s plates 22 At
one end decenclng bars 23 are 110 welded to the respective tubes 21
and serve to mount a cross spindle 24 on h ih is pivoted a lifting
hanlmle 25 in the form of an elbowed steel tube Adjacent its
articulated end the handle 25 has an outstanding fin 26 which is 115
connected by a pivot pin 27 to a bracket 28 carrying a "first" jaw 29.
Slidably mounted at the oipposite end of the frame is a bracket 30
which is of inverted channel f Grm with thle downturned limbs 120
adjoined by a cross piece 31 A pair of ears 32 extends laterally from,
the side limbs of the bracket 30 for a nurpose to be referred to
below.
Welded to the upper side of the bracket 30 125 is a tubular sleeve 33
forming a socket for receiving a second lifting handle the end only of
which is seen at 34 in the drawings A push-in pin 35 is used to secure
this removable handle 34 in the sleeve 33 130 of the slab and thereby
to urge the latter against the second jaw 43 An upward lift on the
handles 46 and 48, in raising the slab 42 from the ground,
simultaneously produces a tightening of the clamping effect between
the 70 two jaws.
It is to be noted that provision is made for varying the effective
width of the frame in this appliance Thus the cross member 52 is made
telescopic, as will be seen froin Figure 75 7, whilst the cross plate
50 is provided with additional apertures 53 for receiving the bolts 54
by means of which it is attached to the lugs 49 Although only two such
additional apertures 53 have been shown, it will be 80 appreciated
that a series may be provided At the other end of the frame, the arms
41 can be inserted through a similar series of apertures in the jaw
bar 43 and be affixed by nuts, such as 55 85 Again, this embodiment of
the invention may be varied by replacing the handle and jaw mechanism
43-47 by another handle assembly of the form used at the left hand end
of the frame 90
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* GB784717 (A)
Description: GB784717 (A) ? 1957-10-16
Improvements in or relating to commutators for dynamo-electric machines
Description of GB784717 (A)
PA Th M' SPPECIFICATION
7
Date of filing Complete Specification Sept 27, 1955.
Application Date Sept27, 1954 No 278 j) Complete Specification
Published Oct16, 1957.
Index at Acceptance:-Classes 83 ( 2), A 44; 83 ( 4), 54; and 95, B 4
X.
International Classification: -105 B 23 k, p.
COMPLETE SPECIFICATION
Improvements in or reiating to Comnmutators for DynamoElectric
Machines We, WATLIFF COMPANY LIMITED, a British Company of Lombard
Road, Morden Road, South Wimbledon, S W 19, and WILLIAM ELI ARNOLD, a
British Subject, of The Old Beech Cottage, Dene Road, Ashstead,
Surrey, 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: -
The present invention relates to commutators for dynamo-electric
machines having a wound rotor.
When a commutator is fitted to such a dynamo-electric machine the
commutator is first slipped on to the armature shaft The armature
leads are then positioned in contact with the commutator segments and
are attached thereto, often by dip-soldering In this latter process,
the axis of the rotor to which the commutator is affixed is held
vertically with the cotmmutator lowermost The rotor is lowered into a
bath of molten solder until the surface of the solder reaches the
connections and soldering of the armature leads to the commutator
segments is effected In this case, substantially the whole of the
commutator is immexsrd in the molten solder.
Impregnation of the armature leads with varnish follows at a later
stage after which the commutator is finished, e g by turning on a
lathe or by grinding to remove excess solder forming electrical
bridges between the segments Finally, in one method of commutator
construction, saw cuts are made in the intersegment insulating
material where its surface lies flush with the surface of the
segments, and where, as is well-known, it is desirable for the outer
surface of the intersegment insulating material to be recessed with
respect to the commutator segments.
This saw-cutting is a costly operation and it has been appreciated for
some time that it would be an advantage if the recessing between
commutator segments could be carried out during the manufacture of the
commutators.
lPrice 3 s 6 d l Hitherto, when commutators made with undercut
intersegment insulators have been assembled on rotors and soldered by
dipping or other means, a serious difficulty has been encountered in
that solder collects in the recesses causing short-circuits The
removal of this solder is tedious and there is a risk of leaving small
particles of solder or other matter in the recesses which may cause
subsequent electrical trouble In addition, when the rotor is
impregnated with varnish some of this varnish is also liable to
collect in the recesses.
There are also methods of making commutators in which no insulating
material is left between the segments For example, commutators may be
made by a method in which a tube of disc of metal is anchored to a
moulded core by inwardly extending lugs or the like, the tube or disc
being subsequently divided up into segments by saw-cutting The saw
cuts leave comparatively deep recesses which extend down to the
moulded core and into which solder, varnish and dirt is liable to
enter during the processes carried out in connection with the fitting
of such a commutator on the shaft of a dynamo electric machine.
It is already known for electric motor manufactures to fit a
protective cap over the commutator prior to dip soldering, this cap
being a loose fit on the commutator so as to enable it to be removed
therefrom Such a loose cap does not, however, guarantee prevention of
solder running into the inter-segment recesses; and its removal is a
difficult and inconvenient operation since the cap becomes very hot
during dip soldering The cap also has to be cleaned before being
stored for re-use Moreover, if the motor manufacturers produce a wide
range of motors, it will be necessary for them to stock a number of
caps of different sizes and shapes to suit different sizes and shapes
of commutators.
It is also known to arrange above the solder both a cap into which the
commutator is inserted after being mounted on the motor shaft In this
case, either the cap is arranged < 7 84,717 73/54.
so that it can be lowered together with the armature into the solder
bath, or the solder bath is arranged so that it can be raised the
required distance for effecting the dip-soldering operation Both
arrangements necessitate the provision of a relatively complicated
raising and lowering mechanism and, as in the previously described
known method, it is desirable to provide different sizes and shapes of
cap to suit different sizes and shapes of commutator The substitution
of one such cap for another is likewise a difficult and inconvenient
operation.
The present invention has for its object to remove these disadvantages
and with this object in view there is provided according to the
present invention a method of masking a commutator of the kind in
which the intersegment insulators are shaped to provide intersegment
recesses between the parts of the commutator segments constituting the
commutator brush surface, so as to prevent solder and/or varnish from
becoming lodged in the intersegment recesses when, after the
commutator has been mounted on the rotor shaft of a dynamoelectric
machine, said commutator is dipped in a bath of molten solder for
connecting the commutator segments to the rotor windings and/or said
windings are treated to impregnate them with an electrically
insulating varnish, comprising the step of fitting a mask of
protective material tightly over the completed commutator so as to
cover said intersegment recesses and to engage in surface-to-surface
contact with all those external parts of the commutator segments which
border the sides and ends of said intersegment recesses.
The term " intersegment insulators ", except where the context
indicates otherwise, is to be interpreted to include not only
separately formed intersegment insulating components but also parts of
insulating material between adjacent segments which are integral with
the commutator body.
The invention also includes a masked commutator prepared by this
method as well as the utilization of such a masked commutator in the
manufacture of a rotor for a dynamo electric machine by methods
comprising the steps of fitting the said masked commutator on the
shaft of the rotor, positioning the terminal wires of the rotor
windings adjacent the parts of the segments to which they are required
to be connected; thereafter either making electrically conducting
connections between the terminal wires and the segment parts by dip
soldering, or alternatively making electrically conducting connections
between the terminal wires and the segment parts and then treating the
rotor with an electrically insulating varnish so as to impregnate the
windings thereof; and finally removing the mask The resulting rotor
also forms part of this invention.
The invention is illustrated by way of example with reference to the
accompanying drawings, in which: Fig 1 is a vertical longitudinal
section of a commutator fitted with a mask, Fig 2 is a perspective
view of the commutator and mask shown in Fig 1, Fig 3 is a fragmentary
perspective view 70 showing this commutator and mask assembled on the
rotor shaft of an electric motor, and Fig 4 is a view similar to Fig 2
illustrating a modification.
The same references are used to indicate like 75 parts in all these
figures.
Referring to the drawings and particularly to Figs 1 and 2, the
commutator comprises an assembly of contact segments 1 and
intersegment insulators 2 embedded in a moulded 80 synthetic resin
core 3 carried on a metal sleeve 10, the intersegment insulators 2
being shaped to provide intersegment recesses 4 Fitted tightly over
this commutator is a cap of thin aluminium foil indicated generally by
reference 85 The crown portion 6 of the cap 5 is formed with a
circular opening 7 of slightly larger diameter than the interior bore
8 of the commutator so that it covers the ends of the segments 1,
while the rim 9 thereof finishes a short 90 distance away from the
lugs 11 of the contact segments 1 The cap thus completely masks the
intersegment recesses 4 and tightly grips the parts of the segments
which contain them.
After the completed assembly consisting of 95 the commutator and cap
has been fitted over the rotor shaft 12 of an electric motor, the
terminal wires 13 of the rotor windings are inserted into slots 14
provided in the lugs 11.
The rotor is now tilted into a position in which 100 the axis of its
shaft 12 is vertical and the commutator lowermost, after which it is
dipped in a bath (not shown) of molten solder to such a depth that the
surface of the solder covers the terminal lugs As a result of this
operation, 105 the ends of the terminal wires 13 in the slots 14 are
soldered to the lugs 11.
In a subsequent operation, the rotor is treated with an electrically
insulating varnish so as to impregnate the windings 110 The cap 5,
being made of aluminium foil, is not easily wetted by solder and
effectively masks the brush surface of the commutator during the
above-mentioned soldering and varnishing operations, so that no solder
or 115 varnish can become lodged in the intersegment recesses 4.
The mask is subsequently removed either by tearing it off or by
turning it off on a lathe.
In order to enable the electrical insulation 120 between the segments
of the commutator to be tested while the cap 5 is in position, either
this cap or the outside of the commutator or both may be given a
coating of an electrically insulating synthetic resin varnish Any
coating 125 on the commutator if of course eventually removed after
removing the cap 5.
Fig 4 illustrates a modification in which the commutator is provided
with a boss 15, but is otherwise similar to the commutator 130 1
784,717 -784,717 described with reference ot Figs 1 to 3 In this case,
the cap 5 is extended as at 16 to cover this boss and part of its end
surface.
Among the advantages of the masks described above are that they offer
protection to the copper segments against annealing in the solder bath
In the embodiment according to Figs 1 to 3, where the mask extends
over the front face of the commutator, substantially all insulating
material between the segments and the centre sleeve of the commutator
is protected against the effects of solder dipping, mechanical damage
or dirt until the cap is removed at the final stage of manufacture In
commutators made with a synthetic resin core, the cap thus extended is
particularly valuable in reducing temperature effects such as
blistering of the resinous material.
While aluminium foil is a particularly advantageous material for the
masks for the reasons just mentioned, many other materials can be used
instead, such as for example heavy fibrous materials which may, if
desired, be impregnated with a synthetic resin When using electrically
non-conducting materials such as this, there is of course no need to
coat the mask or the commutator in order to enable the latter to be
tested electrically with the mask in position.
Although the embodiments of the invention described above and
illustrated in the accompanying drawings all utilize drum type
commutators, it will be appreciated that the invention is likewise
applicable to " disc type " commutators i e to commutators in which
the segments combine to form a disc with a brush surface on one face
thereof.
Moreover, the invention is applicable to rivetted type commutators as
well as to moulded type commutators.
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