Weighing machines

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A weighing scale (usually just "scales" in UK and Australian English, "weighing machine" in south asian english or "scale" in US English) is a measuring instrument for determining the weight or mass of an object. A spring scale measures weight by the distance a spring deflects under its load. A balance compares the torque on the arm due to the sample weight to the torque on the arm due to a standard reference weight using a horizontal lever. Balances are different from scales, in that a balance measures mass (or more specifically gravitational mass), whereas a scale measures weight (or more specifically, either the tension or compression force of constraint provided by the scale). Weighing scales are used in many industrial and commercial applications, and products from feathers to loaded tractor-trailers are sold by weight. Specialized medical scales and bathroom scales are used to measure the body weight of human beings.

History

The balance scale is such a simple device that its usage likely far predates the evidence. What has allowed archaeologists to link artifacts to weighing scales are the stones for determining absolute weight. The balance scale itself was probably used to determine relative weight long before absolute weight.

The oldest evidence for the existence of weighing scales dates to c. 2400-1800 B.C.E. in the Indus River valley

(modern-day Pakistan). Uniform, polished stone cubes discovered in early settlements were probably used as weight-setting stones in balance scales. Although the cubes bear no markings, their weights are multiples of a common denominator. It is interesting to note that the cubes are made of many different kinds of stones with varying densities. Clearly their weight, not their size or other characteristics, was a factor in sculpting these cubes. In Egypt, scales can be traced to around 1878 B.C.E., but their usage probably extends much earlier. Carved stones bearing marks denoting weight and the Egyptian hieroglyphic symbol for gold have been discovered, which suggests that Egyptian merchants had been using an established system of weight measurement to catalog gold shipments and/or gold mine yields. Although no actual scales from this era have survived, many sets of weighing stones as well as murals depicting the use of balance scales suggest widespread usage.

Variations on the balance scale, including devices like the cheap and inaccurate bismar began to see common usage by c. 400 B.C.E. by many small merchants and their customers. A plethora of scale varieties each boasting advantages and improvements over one another appear throughout recorded history, with such great inventors as Leonardo Da Vinci lending a personal hand in their development.

Even with all the advances in weighing scale design and development, all scales until the seventeenth century C.E. were variations on the balance scale. Although records dating to the 1600s refer to spring scales for measuring

weight, the earliest design for such a device dates to 1770 and credits Richard Salter, an early scale-maker. Spring scales came into common usage in 1840 when R. W. Winfield developed the candlestick scale for use in measuring letters and packages. Postal workers could work more quickly with spring scales than balance scales because they could be read instantaneously and did not have to be carefully balanced with each measurement.

By the 1940s various electronic devices were being attached to these designs to make readings more accurate. These were not true digital scales as the actual measuring of weight still relied on springs and balances. Load cells, small nodes that convert pressure to a digital signal, have their beginnings as early as the late-nineteenth century, but it was not until the late-twentieth century that they became accurate enough for widespread usage.

Balance

A precision balance scale for weighing silver and gold located on display at the Historic Archive and

Museum of Mining in Pachuca, Mexico.

The balance (also balance scale, beam balance and laboratory balance) was the first mass measuring instrument invented. In its traditional form, it

consists of a pivoted horizontal lever of equal length arms, called the beam, with a weighing pan, also called scale, scalepan, or bason(obsolete), suspended from each arm (which is the origin of the originally plural term "scales" for a weighing instrument). The unknown mass is placed in one pan, and standard masses are added to the other pan until the beam is as close to equilibrium as possible. In precision balances, a slider mass is moved along a graduated scale. The slider position gives a fine correction to the mass value. Although a balance technically compares weights, not masses, the weight of an object is proportional to its mass, and the standard weights used with balances are usually labeled in mass units.

Two 10-decagram masses

Balances are used for precision mass measurement, because unlike spring scales their accuracy is not affected by differences in the local gravity, which can vary by almost 0.5% at different locations on Earth. A change in the strength of the gravitational field caused by moving the balance will not change the measured mass, because the moments of force on either side of the balance beam are affected equally.

Very precise measurements are achieved by ensuring that the balance's fulcrum is essentially friction-free (a knife edge is the traditional solution), by attaching a pointer to the beam which amplifies any deviation from a balance position; and finally by using the lever principle, which allows fractional masses to be applied by movement of a small mass along the measuring arm of the beam, as described above. For greatest accuracy, there needs to be an allowance for the buoyancy in air, whose effect depends on the densities of the masses involved.

The original form of a balance consisted of a beam with a fulcrum at its center. For highest accuracy, the fulcrum would consist of a sharp V-shaped pivot seated in a shallower V-shaped bearing. To determine the mass of the object, a combination of reference masses was hung on one end of the beam while the object of unknown mass was hung on the other end (see balance and steelyard balance). For high precision work, the center beam balance is still one of the most accurate technologies available, and is commonly used for calibrating test weights.

To reduce the need for large reference masses, an off-center beam can be used. A balance with an off-center beam can be almost as accurate as a scale with a center beam, but the off-center beam requires special reference masses and cannot be intrinsically checked for accuracy by simply swapping the contents of the pans as a center-beam balance can. To reduce the need for small graduated reference masses, a sliding weight called a

poise can be installed so that it can be positioned along a calibrated scale. A poise adds further intricacies to the calibration procedure, since the exact mass of the poise must be adjusted to the exact lever ratio of the beam.

For greater convenience in placing large and awkward loads, a platform can be floated on a cantilever beam system which brings the proportional force to a nose iron bearing; this pulls on a stilyard rod to transmit the reduced force to a conveniently sized beam. One still sees this design in portable beam balances of 500 kg capacity which are commonly used in harsh environments without electricity, as well as in the lighter duty mechanical bathroom scale (which actually uses a spring scale, internally). The additional pivots and bearings all reduce the accuracy and complicate calibration; the float system must be corrected for corner errors before the span is corrected by adjusting the balance beam and poise. Such systems are typically accurate to at best 1/10,000 of their capacity, unless they are expensively engineered.

Some high-end mechanical balances also use dials (with counterbalancing masses instead of springs), a hybrid design with some of the accuracy advantages of the poise and beam but the convenience of a dial reading. These designs are expensive to produce and have become largely obsolete due to the advent of electronic balances.Milligram scale

A&D Orion series. Model HR-60 is one of very few Legal for Trade (NTEP in USA) certified scales

approved for 1 milligram readability.

Milligram scales are typical used for industrial, research, chemical, pharmaceutical, electronics, precious metals, jewelry (commonly sold as "carat scale", "diamond scale", and "jewelry scale"), and educational applications.Analytical balance

An analytical balance is used to measure mass to a very high degree of precision and accuracy. The measuring pan(s) of a high precision (0.1 mg or better) analytical balance are inside a transparent enclosure with doors so that dust does not collect and so any air currents in the room do not affect the balance's operation. The use of a vented balance safety enclosure, which has uniquely designed acrylic airfoils, allows a smooth turbulence-free airflow that prevents balance fluctuation and the measure of mass down to 1 μg without fluctuations or loss of product. Also, the sample must be at room temperature to prevent natural convection from forming air currents inside the enclosure, affecting the measure of mass.

Analytical precision is achieved by maintaining a constant load on the balance beam, by subtracting mass on the same side of the beam to which the sample is added. The

final balance is achieved by using a small spring force rather than subtracting fixed masses. This makes calling it an "analytical balance" a misnomer, because it should actually be called an "analytical scale", due to it measuring force, rather than gravitational mass.

Spring scale

A spring weighing scale can measure forces transmitted through the scale in any direction.

Main article: Spring scale

In a typical spring scale, the spring stretches (as in a hanging scale in the produce department of a grocery store) or compresses (as in a simple bathroom scale) in proportion to how hard the Earth pulls down on the object. It is therefore affected by the local gravity. Every spring has a proportionality constant that relates how hard it is

pulled to how far it stretches. Some weighing scales such as a Jolly balance (named after Philipp von Jolly who invented the balance about 1874) use a spring with a known spring constant (see Hooke's law) and measure the displacement of the spring by any variety of mechanisms to produce an estimate of the gravitational force applied by the object, which can be simply hung from the spring or set on a pivot and bearing platform. Rack and pinion mechanisms are often used to convert the linear spring motion to a dial reading.

Spring scales measure weight , or more precisely, the tension force of constraint acting on an object, opposing the force of gravity. They are usually calibrated in units of force such as newtons or pounds-force. They have two sources of error that balances do not; the measured weight varies with the strength of the local gravitational force, by as much as 0.5% at different locations on Earth, and the elasticity of the measurement spring can vary slightly with temperature. Spring scales which are legal for commerce either have temperature compensated springs or are used at a fairly constant temperature, and must be calibrated at the location in which they are used, to eliminate the effect of gravity variations.

Strain gauge scale

Digital kitchen scale, a strain gauge scale which works by the spring principle.

In electronic versions of spring scales, the deflection of a beam supporting the unknown weight is measured using a strain gauge, which is a length-sensitive electrical resistance. The capacity of such devices is only limited by the resistance of the beam to deflection. The results from several supporting locations may be added electronically, so this technique is suitable for determining the weight of very heavy objects, such as trucks and rail cars, and is used in a modern weighbridge.

Hydraulic or pneumatic scale

It is also common in high-capacity applications such as crane scales to use hydraulic force to sense weight. The test force is applied to a piston or diaphragm and transmitted through hydraulic lines to a dial indicator based on a Bourdon tube or electronic sensor.

Testing and certification

Scales used for trade purposes in the State of Florida, as this scale at the checkout in a cafeteria,

are inspected for accuracy by the FDACS's Bureau of Weights and Measures.

Most countries regulate the design and servicing of scales used for commerce. This has tended to cause scale technology to lag behind other technologies because expensive regulatory hurdles are involved in introducing new designs. Nevertheless, there has been a recent trend to "digital load cells" which are actually strain-gauge cells with dedicated analog converters and networking built into the cell itself. Such designs have reduced the service problems inherent with combining and transmitting a number of 20 millivolt signals in hostile environments.

Government regulation generally requires periodic inspections by licensed technicians using weights whose calibration is traceable to an approved laboratory. Scales intended for casual use such as bathroom or diet scales may be produced, but must by law be labeled "Not Legal for Trade" to ensure that they are not repurposed in a way that jeopardizes commercial interest. In the United States,

the document describing how scales must be designed, installed, and used for commercial purposes is NIST Handbook 44. Legal for Trade certification usally approve the readability as repeatability/10 to ensure a maximum margin of error of 10%.

Because gravity varies by over 0.5% over the surface of the earth, the distinction between force due to gravity and mass is relevant for accurate calibration of scales for commercial purposes. Usually the goal is to measure the mass of the sample rather than its force due to gravity at that particular location.

Traditional mechanical balance-beam scales intrinsically measured mass. But ordinary electronic scales intrinsically measure the gravitational force between the sample and the earth, i.e. the weight of the sample, which varies with location. So such a scale has to be re-calibrated after installation, for that specific location, in order to obtain an accurate indication of mass.

See Verification and validation for further information

Supermarket/retail scale

These scales are used in the bakery, delicatessen, seafood, meat, produce, and other perishable departments. Supermarket scales can print labels and receipts (in bakery specially), marks weight/count, unit price, total price and in some cases tare, a supermarket label prints weight/count, unit price and total price. Some modern supermarket scales print an RFID tag that can be used to track the item for tampering or returns. In most cases these type of scales

have a sealed calibration so that the reading on the display is correct and cannot be tampered with - in the USA the approval is NTEP, for South Africa it is SABS, the UK it is OIML.

Sources of error

An old two pan balance.

Balance with a counterweight to small objects weighing 0-100 grams.

Some of the sources of error in high-precision balances or scales are:

Buoyancy , because the object being weighed displaces a certain amount of air, which must be accounted for. Some high-precision balances may be operated in a vacuum.

Error in mass of reference weight Air gusts, even small ones, which push the scale up or

down Friction  in the moving components that cause the scale

to reach equilibrium at a different configuration than a frictionless equilibrium should occur.

Settling airborne dust contributing to the weight Mis-calibration over time, due to drift in the circuit's

accuracy, or temperature change Mis-aligned mechanical components due to thermal

expansion/contraction of components Magnetic fields  acting on ferrous components Forces from electrostatic fields, for example, from feet

shuffled on carpets on a dry day Chemical reactivity between air and the substance

being weighed (or the balance itself, in the form of corrosion)

Condensation  of atmospheric water on cold items Evaporation  of water from wet items Convection  of air from hot or cold items Gravitational anomalies for a scale, but not for a

balance. I.e. using the scale near a mountain; failing to level and recalibrate the scale after moving it from one geographical location to another)

Vibration and seismic disturbances; for example, the rumbling from a passing truck

Software

An ongoing problem within the free software community is the lack of free software for analytical balances which is currently is debated by some manufacturers.

Symbolism

The scales (specifically, a two pan, beam balance) are one of the traditional symbols of justice, as wielded by statues of Lady Justice. This corresponds to the use in metaphor of matters being "held in the balance". It has its origins in ancient Egypt.

Tare weight

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Tare (pronounced /ˈtɛər/), from the Middle French word tare "wastage in goods, deficiency, imperfection" (15c.), from Italian tara, from Arabic tarah, lit. "thing deducted or rejected," from taraha "to reject" weight, sometimes called unladen weight, is the weight of an empty vehicle or container. By subtracting it from the gross weight (laden weight), the weight of the goods carried (the net weight) may be determined. This can be useful in computing the cost of the goods carried for purposes of taxation (sometimes called a tariff) or for tollsrelated to barge, rail, road, or other traffic, especially where the toll will vary with the value of the goods carried (e.g., tolls on the Erie Canal). Tare weight is often published upon the sides of railway cars and transport vehicles to facilitate the computation of the load carried. Tare weight is also used in body composition assessment when doing underwater weighing.

Tare weight is often accounted for in kitchen and analytical (scientific) weighing scales, which often include a button that resets the zero of the scale to a higher value, in order

to measure only the content of a container without measuring the weight of the container itself.

weighbridge

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Weighbridge redirects here. For place names see Weybridge and Wadebridge.

A weigh bridge at a gravel pit. The weigh bridge is the two part platform over which trucks are

driven. The upper works is auxiliary equipment for leveling the load in the truck and is not part of

the scale. This scale uses electronic measuring equipment.

Truck scales (US) or weigh bridges (non-US) are large scales, usually mounted permanently on a

concrete foundation, that are used to weigh entire vehicles and their contents. By weighing the vehicle both empty and when loaded, the load carried by the vehicle can be calculated. The key component that

uses a weighbridge in order to make the weigh measurement is load cells.

Types

Electronic (deep pit type)

Electronic (shallow pit)

Electronic (pitless type)

Digital (deep pit type)

Digital (shallow pit)

Digital (pitless type)

Mechanical weighbridge

Mechanical (digital type)

Electro-mechanical

Portable weigh bridge

Axle scales

Portable ramp end scales

Design

Electronic indicator for the bridge shown above. This allows input of the vehicle empty weight

and can compute and display the amount of material.

A moveable weigh bridge

Truck scales can be surface mounted with a ramp leading up a short distance and

the weighing equipment underneath or they can be pit mounted with the weighing

equipment and platform in a pit so that the weighing surface is level with the road.

They are typically built from steel or concrete and by nature are extremely robust.

In earlier versions the bridge is installed over a rectangular pit that contains levers

that ultimately connect to a balance mechanism. The most complex portion of this

type is the arrangement of levers underneath the weigh bridge since the response of

the scale must be independent of the distribution of the load. Modern devices use

multiple load cells that connect to an electronic equipment to totalize the sensor

inputs. In either type of semi-permanent scale the weight readings are typically

recorded in a nearby hut or office.

Many weighbridges are now linked to a personal computer which runs truck scale

software capable of printing tickets and providing reporting features.

Usage

Truck scales can be used for two main purposes:

Selling or charging by weight over the bridge (Trade Approved)

Check weighing both axle weights and gross vehicle weights. This helps to stop axle

overloading and possible heavy fines.

They are used in industries that manufacture or move bulk items, such as in mines

or quarries, garbage dumps / recycling centers, bulk liquid and powder movement,

household goods, and electrical equipment. Since the weight of the vehicle carrying

the goods is known (and can be ascertained quickly if it is not known by the simple

expedient of weighing the empty vehicle) they are a quick and easy way to measure

the flow of bulk goods in and out of different locations.

A single axle truck scale or axle weighing system can be used to check individual

axle weights and gross vehicle weights to determine whether the vehicle is safe to

travel on the public highway without being stopped and fined by the authorities for

being overloaded. Similar to the full size truck scale these systems can be pit

mounted with the weighing surface flush to the level of the roadway or surface

mounted.

For many uses (such as at police over the road truck weigh stations or temporary

road intercepts) weigh bridges have been largely supplanted by simple and thin

electronic weigh cells, over which a vehicle is slowly driven. A computer records the

output of the cell and accumulates the total vehicle weight. By weighing the force of

each axle it can be assured that the vehicle is within statutory limits, which typically

will impose a total vehicle weight, a maximum weight within an axle span limit and

an individual axle limit. The former two limits ensure the safety of bridges while the

latter protects the road surface.

About the company

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CHAPTER 4

Averys Limited

4.1. Averys Ltd is the holding company for the 32 operating companies in

the Avery Group. The Group's main activity is the design, manufacture, sale

and servicing of a wide range of weighing machines, physical testing machines

and fluid measuring equipment.

History of the company

4.2. The company's history can be traced back to 1730 and the manufacture

by hand of steelyards and beam scales in a small workshop in Birmingham.

In the early part of the nineteenth century the business passed to the Avery

family. It was developed from a purely Midlands concern into a nationwide, and

finally, under the family's successors, into a worldwide organisation.

4.3. The firm of W & T Avery was incorporated as a private company in 1891.

This was the predecessor of W & T Avery Ltd, now the main operating company

in Averys' weighing and testing machine division, and it became a public

company in 1894. A year later the Soho Foundry at Smethwick was purchased

and rebuilt as the company's main factory. When legislation was introduced

at the turn of the century requiring the stamping of all weighing machines used

for trade Avery branches were set up in some 100 towns in the United Kingdom.

This was the beginning of the sales and service organisation that has expanded

to cover not only every important town in the United Kingdom but also has

been established in many overseas countries.

4.4. From the formation of the firm of W & T Avery until the present day

there has been a continual expansion by the acquisition of other companies to

form the Group as it exists today. Some of the principal acquisitions in the

United Kingdom were:

1899 Parnall & Sons Ltd

1920 Southall and Smith Ltd (50 per cent), balance acquired in 1928

1920 Saml Denison & Son Ltd (name changed to Avery-Denison Ltd in

1970)

1925 Oertling Ltd

1931 The Tan Sad Chair Co (1931) Ltd

1932 Avery-Hardoll Ltd

1953 Pump Maintenance Ltd (50 per cent), balance acquired in 1976

1959 Geo Driver & Son Ltd, merged in 1966 with Southall and Smith Ltd

to form Driver Southall Ltd

1968 Stanton Redcroft Ltd

1973 Telomex Ltd.

Averys owned companies in some European countries but these were unprofitable and were wound up before 1939 except for a manufacturing company in

West Germany which was sold to a German manufacturer in 1968 because its

business also proved unprofitable. In Averys' view it had never achieved a

large enough share of the German market for its own products. It was not

13reckoned worth preserving as a distributor of Averys' products from the United

Kingdom. From 1900 onwards Averys have gradually established the overseas

companies listed in Appendix 5.

Present organisation

4.5. In 1958 the holding company, Averys Ltd, was formed and in 1971, to

provide for greater specialisation and management efficiency and co-ordination,

a divisional structure was created in which the operating companies were

grouped in three Divisions: Weighing and Testing, General Products, and

International. The principal companies in each Division with their activities

are set out in Appendix 5, and a chart showing the organisation of the Avery

Group is set out in Appendix 6.

The business of the Avery Group

4.6. Two-thirds of Averys' group turnover lies broadly speaking in the sales

of new products and one-third in service contracts for machine maintenance

and updating. Averys' estimates of its share of its principal United Kingdom

markets are set out in Appendix 7. Sales between Averys and GEC in 1978

were small in relation to the companies' turnovers. Most of Averys' weighing

and measuring machines are standard, but machines are also designed and

constructed to customers' special needs and specifications. Averys' most

successful weighing machine using microprocessors is the 1750 retail weighing

scale which accounts for one-fifth by value of sales of new goods of the entire

Avery group.

4.7. Averys considers that a substantial demand will continue both in the

United Kingdom and overseas for mechanical equipment. Meeting this will

continue to be an important part of the company's operations. At Appendix 8

are figures showing the orders received by W & T Avery, Oertling and Avery

Export for the years 1976 to 1978 split into those for mechanical weighing

machines and those for electronic. The figures in the top half of the table are

in prices at which the orders were taken, those in the lower half have been

adjusted for price increases to take account of inflation. In the three years total

mechanical orders rose from £12-7 million to £15-2 million but when adjusted

for price increases the figure is virtually constant (£11-9 million, £10-5 million

and £11-2 million at January 1976 prices). Orders for electronic machines rose

from £8-8 million to £18-1 million, which when adjusted for price increases

rose from £8-3 million to £13-3 million at January 1976 prices, a substantial

increase. Orders for export of mechanical scales show an increase from £3-9

million to £5-4 million at January 1976 prices, an indication that demand for

this type of scale overseas is increasing.

4.8. Averys supplies machines to any user or systems supplier wishing to

incorporate weighing and/or liquid dispensing equipment in industrial or retail

systems. The situation can arise in which Averys' tenders may be accepted

regardless of who obtains the main contract. Averys told us it had supplied

63 baggage weighers for London Heathrow Terminal 2, 19 for Edinburgh

Airport and 21 for Glasgow when the successful contractors, one of whom

was GEC, were different in each of the three cases. Of 14 contractors who

submitted tenders for a main airport contract in baggage weighing overseas

14Averys quoted to all but four, was successful with one but would still have

obtained an order if any other of the ten had obtained the main contract.

4.9. Avery-Hardoll Ltd manufactures meter pumps, bulkmeters and couplings

for petrol and fuelling equipment including aircraft refuelling. It estimates that

it has approximately 20 per cent of the United Kingdom market for petrol

pumps, that its share is growing and that about 50,000 mechanical pumps

will in due course have to be converted or replaced by electronic pumps at

a cost of some £125 million at current prices. It has recently introduced its

Mark V microprocessor-based pump, and will shortly introduce kiosk equipment incorporating microprocessors. In the more distant future there is the

possibility of using cards for automatic direct debiting of customers at retail

petrol stations; Avery-Hardoll Ltd is discussing with some card and oil

companies the role its pumps may play in such business. It exports some 50 per

cent of its total output through some 60 overseas outlets to 90 countries.

Sales and servicing

4.10. Sales promotion in the main operating companies of Averys at home

and overseas is carried out mainly through separate sales forces for each

company. Other forms of sales promotion include advertising and participation

in exhibitions and conferences, and the service organisations will bring to the

attention of their company managements sales opportunities revealed during

maintenance or repairs. The size of the sales force is related to each company's

requirements; thus W & T Avery Ltd, the largest subsidiary, has 173 sales

representatives while Avery-Hardoll Ltd which deals with a few principal

customers, the oil companies, has eight. Representatives also act as consultants

to users in determining the equipment they need. Specialist sales supervisors

in each company support and control the activities of the representatives, and,

in turn, report to marketing or sales managers who are responsible to their

board.

4.11. Servicing is a major preoccupation of Averys for two principal

reasons:

(i) Most of the products must be continually maintained to comply with

weights and measures legislation. W & T Avery Ltd alone has 127,716

maintenance contracts covering 456,000 weighing machines. Another

company, Pump Maintenance Ltd, services over 84,000 measuring

pumps and meters each year.

(ii) Apart from the statutory requirements, users of weighing and liquid

measuring equipment of the kind designed and marketed by Averys

require for commercial reasons the highest level of performance

throughout the life of the product.

4.12. Approximately 50,000 weighing machines are repaired for users each

year. The company normally expects to answer a call on the day it is received

and provides a Saturday emergency service for retailers, and special services

to manufacturers having continuous processes. There are 250 sales and servicing

branches for weighing and testing products, strategically located throughout

the United Kingdom and the Irish Republic.

4.13. Details of Averys' service organisation in the United Kingdom and

within the 15 companies of Averys' International Division involved in the

15manufacture, sale and servicing of weighing and testing machines overseas are

given at Appendix 9. In the countries other than those covered by the overseas

companies of the International Division, sales and servicing are carried out by

distributors. Avery Export Ltd has 65 such distributors. Distributors appointed

by Avery Export Ltd are required as a condition of appointment to undertake

to establish service facilities for Averys' products, and to arrange for the

training of their service personnel in the United Kingdom.

Exports

4.14. Approximately 30 per cent by value of the weighing and measuring

units manufactured by Averys are exported. Some companies in the Group

exceed this figure, such as Avery-Hardoll Ltd which exports 50 per cent and

Driver Southall Ltd, which exports 40 to 45 per cent of their respective production. The Group provides sales and service facilities in most countries of the

world outside the United Kingdom and in 1977 shipped its products to

107 countries. Its exports tend to be concentrated in those areas—Africa, the

Far East and Middle East—with which the United Kingdom has strong

traditional trade links. A regional analysis of Averys' export sales is at

Appendix 10.

4.15. Averys operates manufacturing plants in Australia, New Zealand, India

and South Africa. Although, in the main, these units depend on design knowledge provided by the home companies (for which royalties are paid) they are

also engaged in the modification and development of equipment to suit local

markets.

4.16. The status of Avery Nigeria Ltd changed in 1978 as a result of Nigerian

legislation from a subsidiary to an associated company in which the Group's

holding of the equity has been reduced from 60 per cent to 40 per cent. Avery

India Ltd expects to comply with Indian Government requirements for increased

local participation in the autumn of 1979. The result will be to reduce the

holding of Averys Ltd to approximately 40 per cent of the equity from its

present level of 60 per cent.

4.17. In Averys' view the weighing machine market in which it operates has

specialised requirements so that its best chance of success in export markets,

where it is not well established, is by association with other specialist weighing

machine companies already established there, or by acquisition. Averys already

has several close relationships with other manufacturers. The Group is the

largest shareholder in Servo-Balans BV (Holland), it has an interest in Schember

AG (Austria) and it has plans for forming associations with other European

manufacturers. A joint arrangement with an American manufacturer is now

under consideration.

Technology

4.18. Although Averys' business was for many years based primarily on

high quality mechanical engineering, which remains an essential part of its

technology, it has also adopted developments in other fields of technology

where they could contribute to its activities. It says that it was the first in the

United Kingdom to produce electrically operated weighing recorders in the

1930s. Since the Second World War it has employed such technologies as

optical projection, digital encoding and, since 1963, electronic weighing.

164.19. Involvement in electronics goes back more than twenty years and,

by the early 1970s, the company was established in electronic weighing equipment. It was producing a microprocessor-based unit in 1973 and there are

now many Avery scales in use, in the United Kingdom and overseas, employing

these devices. Microprocessor technology has been adopted by all the weighing

and measuring companies of the Group. The Applied Research Unit, more

fully described in paragraph 4.23, has been established for dissemination of

information on this technology throughout the companies of the Group.

Research and development

4.20. Research is organised at three levels, the United Kingdom subsidiary

companies, the Avery Research Administration and the Applied Research Unit.

4.21. As each company concentrates on a particular sector of the Group's

products it is responsible for research and development in its sector. In Averys'

view this ensures that design and development are carried on close enough to

the selling and manufacturing operations to be influenced by them. The sales

organisations report on present and forward market requirements, on competitors' activities and on orders lost and the technical departments make

proposals for new or improved products. Special orders developed for individual

customers may lead to the creation of standard products for a wider market.

4.22. The Avery Research Administration is charged with co-ordinating the

research and development activities of the individual companies, to see that

the programme of each is adequate and that there is no duplication of effort.

It is controlled by a board consisting of the Chairman of Averys, the Directors

responsible for the three operating divisions of the company, who are also

members of the board of Averys, and the Director of the unit.

4.23. The Applied Research Unit leads the company's search for new

products. In the main it is a long range development laboratory for W & T

Avery Ltd, but is sited away from that company's main factory in order to

keep it free from day-to-day activities. Its purpose is to examine all relevant

new technologies, investigate their possible application to the company's

products and develop advanced design concepts to the stage of practical

application. It does not proceed beyond the production of working models.

4.24. Averys' total revenue expenditure on research in the United Kingdom

in the year ended 31 December 1977 was £1-7 million, 3-2 per cent of its new

goods sales in the United Kingdom. The new premises now housing the

Applied Research Unit involved a capital cost of £600,000.

Averys' advisory role

4.25. Averys has been closely concerned with Government departments for

more than 50 years in connection with the policy and framing of weights and

measures legislation. In addition, as occasion has arisen, it has been engaged

with various official bodies of the United Kingdom and the EEC on a variety

17of subjects. W & T Avery Ltd is an 'Approved Laboratory' of the British

Calibration Service of the National Physical Laboratory.

Financial information

4.26. The net assets of the Avery group amounted to £65-8 million for the

year ended 31 December 1978. Summaries of the balance sheets and source

and application of funds of the Avery group for the five years to 31 December

1978 are set out at Appendices 11 and 12 respectively. The balance sheets

indicate that the group is largely financed by retained profits. The increase in

fixed assets and bank overdrafts in 1978 largely reflects Averys' entry into the

leasing of equipment. It is intended to lease group products as a sales aid but

as it is expected to be some years before leasing of group products reaches a

substantial level, Averys is currently leasing capital equipment not of group

manufacture. The leasing operations are expected to increase substantially

during the next five years and should reduce the group's tax charge. Expenditure

on fixed assets, of which a substantial part related to motor vehicles, and

excluding leased equipment, averaged some £3 million a year between 1974

and 1978. Expenditure on fixed assets (excluding assets for leasing) over the

next five years is estimated to average £5 million a year at 1979 prices, which

compares with an annual depreciation charge of approximately £4 million

a year. The increase in associated company and trade investments in 1978

was largely due to the reduction of Averys' holding in the equity of its Nigerian

subsidiary (see paragraph 4.16). The statement of source and application of

funds at Appendix 12 indicates that the group until 1977 operated within the

limits of the cash flow generated from its operations. Even at the end of 1978,

when borrowing had been increased by £4£ million to finance the leasing

activity, borrowings represented less than 10 per cent of total funds employed.

Management accounting

4.27. Averys' system of management accounting is based on full quarterly

financial accounts for the group and each of its subsidiaries, supplemented by

monthly returns of sales and orders, and of the cash position for each. Averys

said that it had considered whether it was necessary to produce full group

financial accounts each month, but it was not yet clear that the benefits would

be worth the extra expense. The business was stable and, with the close involvement of the executive directors of the holding company in the affairs of the

subsidiaries, and monthly reporting of sales orders and cash Averys considered

its present arrangements to be adequate. Some small subsidiaries in the United

Kingdom, and some of the subsidiaries abroad, produce monthly accounts,

but these are not formally presented to the holding company.

4.28. Computers have been used for some functions of accounting and production control since about 1970 but Averys was not satisfied with the service

which could be provided. It has retained a considerable proportion of manual

accounting. A new ICL computer system which will provide the service required,

including direct access, is now available and has been installed, and will be

used for production control and for a much greater proportion of the control

and accounting, particularly costing, functions than was covered by the former

computer system.

18Averys and its employees

4.29. The number of employees in the Avery Group at September 1978

was as follows:

United Kingdom 8,589

Overseas 3,962

Total 12,551

Averys claims that its industrial relations are good and it considers that it has

a loyal workforce. It has a high proportion of long-serving employees. The

reaction of the unions to the approach by GEC is dealt with in Chapter 6.

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Avery

Avery

1731James Ford established a business as a maker of 'stilliards' in Digbeth, Birmingham, described at the time as a city with a 'more varied and lively industrial life than any other city in the world'. (However, the company has roots stretching as far back as 1670 and Charkes de Grave who had a shop near St Paul’s Cathedral.

1760James Ford retires and the business passes to William Barton and then toThomas Beach in

1782.

1799Business passes to Joseph Balden, who married Mary Avery.

1813As the Industrial Revolution gathered momentum, the business was transferred to William Avery, soon joined by his brother Thomas, who traded under the name W&T Avery.

1817 –1837Business expands and acquires more premises in Digbeth and opens a London branch Hatton Garden in 1837.  The company now employs almost 200 people.

1870Acquire Atlas Foundry in West Bromwich to carry out iron founding.

1876First Avery weighbridge designed and made by Mr. A W Brown, and ex Boulton & Watt apprentice.

1885Produced the first ticket printing steelyard in 1885.  The company now employs more than 700 people.

1887Introduced the first equipment maintenance contracts as an added service to its customers.  This heralded the beginning of its international service business.

1895Acquired the business of James Watt &Co and the 25 acre Soho Foundry site in Smethwick.

1918Death of W E T Avery, last family member actively involved with the company. It now employs more than 3,000 people.

1963 First load cell weighbridges made at Soho.

1971

First digital retail scale in volume production.

1979W&T Avery became part of the GEC Group of companies.  Major investment to increase production of electronic weighing machines.

1982First volume production retail scale with integral printer and PLU (price look up).

1984First UK manufacture of retail scale with networking facility and data capture facilities,

1993The Berkel company was acquired as a wholly owned GEC subsidiary, and combined with GEC Avery Ltd to trade globally under the Avery Weigh-Tronix name.

2000The Avery Weigh-Tronix group was acquired by Weigh-Tronix Inc.

Platform scales

Our platform scales are used across industry, helping to weigh, handle, monitor, mix and fill a multitude of everyday items, from foodstuffs, to household components, detergents and medicines.

Whatever the application and wherever the location, our heavy-duty platforms can handle loads from 6 kilograms to 20 tonnes.  Choose from bench mounted, standalone, pit-installed, mobile or hazardous area models, with stainless or mild steel finishes to suit your requirements.

There are literally hundreds of combinations of size and capacity, all of which can interface with our range of digital instrumentation to create the ideal configuration for your business.

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Depositing and Liquid Filling

Our filling systems are designed to handle a wide range of liquids and semi-solids in the food, chemical and pharmaceutical industries.   We offer an extensive choice of volumetric, gravimetric, mass flow meter and automatic conveyor fillers for applications across the processing plant, from the raw material store to the packing environment.

From a single head unit, to a multi-head, multi-conveyor system, all our machines are custom designed by specialist Avery Weigh-Tronix engineers to meet your exact requirements.   They can be integrated seamlessly with your production processes for ease of operation and increased management control.

Every volumetric machine features the renowned Neumo pump, synonymous with quality, reliability and endurance.

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Belt Weighing

Avery Weigh-Tronix belt weighing systems are an efficient, cost-effective solution to weighing products on the move. 

Suitable for flat or inclined conveyors, systems can be installed with new equipment or retrofitted to existing belts, to provide accurate measurement and recording of batch weights, flow rates and belt speed.

Load Cells

Since the introduction of electronic weighing, Avery Weigh-Tronix has been at the forefront of load cell technology.

Our comprehensive range includes analogue, digital and vibrating beam loadcells and the innovative weighbar transducer and is suitable for many types of weighing equipment - from retail scales, to vessel weighers, to intrinsically safe systems, to weighbridges. 

Each load cell is designed, developed and manufactured in-house and the entire process is regulated by stringent quality assurance procedures to ensure a lifetime of consistent performance. For added reassurance, all weighing equipment and systems that rely on our load cells carry international Weights and Measures approvals.

www.averyindia.co.in

Avery India Ltd. brings to you its vast experience in field of weighing with access to cutting edge technology from our principals Avery Weigh-Tronix, the global leader in innovative weighing solutions.

Avery India Limited has been supplying weighing machines and weighing automation solutions to customers since 1911. We are the leading Electronic Scale manufacturer in India.

We are an ISO 9001-2000 company. We manufacture world-class products to meet all of our customer needs. Our plant at Ballabhgarh, Haryana, spread over 25 acres, is equipped with state of art facilities to manufacture loadcells, weighing scales and Dispensing pumps. Our range of products include:

WeighBridges Electronic Platform Scales Fuel Dispensers   / Petrol Pumps Belt weighers Weigh feeders Liquid Filling Machines Tank weighers, Hybrid Kits, load cells and develop tailor made products, Software &

Automation Solutions such as unmanned weighing systems as per customers' requirements.

We provide efficient after sales services with our strong network of Service Establishments across India having a totally dedicated team of more than 200 trained Service Engineers/Technicians. Our Services include annual maintenance contracts, repairs, retrofits, capacity enhancements, installations, civil foundations and Calibration & Certification of our products.

Our Subsidiary Salter India Limited located at Ballabgarh specializes in manufacturing mechanical & electronic spring balances.

Belt weigher

A beltweigher or belt weigher is a piece of industrial control equipment used to gauge

the mass or flow rate of material travelling over a troughed (cupped) conveyor belt of

any length which is able to adequately contain the material being weighed. These are

also known as belt scales, dynamic scales, conveyor scales, and in-motion weighers.

Many such check weighers or feed weighers are an active part of the process flow

control of the conveyor line.

A belt weigher replaces a short section of the support mechanism of the belt, which

might be one or more sets of idler rollers, or a short section of channel or plate. This

weighed support is mounted on load cells, either pivoted or fully suspended. Fully

suspended belt weighers are considered to be more accurate due to the turning

moment of the pivot mechanism on pivoted belt belt weighers. The mass measured by

the load cells is integrated to compute the mass of material moving on the belt, after

allowing for the mass of the belt itself. Belt weighers generally include the necessary

electronics to perform this calculation, often in the form of a small

industrialized microprocessor system.

A belt weigher is normally mounted in a well supported straight section of belt, with no

vertical or sideways curvature, and as close to level as is practicable. The weighed

support must be aligned vertically and horizontally with the adjacent supports to avoid

tensile forces in the belt skewing the measurement.

Outputs from belt weighers are typically:

pulses at predefined increments of mass

an analogue signal proportional to the flow rate

In addition, some belt weigher controllers will offer features such as driving an output to

stop the belt when a predefined mass of material has been measured, or a range of

alarms to indicate nil flow, belt slippage and belt stoppage.

Uses include mineral and aggregate extraction, continuous mixing processes, control

of variable rate feeders, port handling and ship loading processes.

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Load cell

A load cell is a transducer that is used to convert a force into electrical signal. This conversion is indirect and happens in two stages. Through a mechanical arrangement, the force being sensed deforms a strain gauge. The strain gauge measures the deformation (strain) as an electrical signal, because the strain changes the effective electrical resistance of the wire. A load cell usually consists of four strain gauges in a Wheatstone bridge configuration. Load cells of one strain gauge (quarter bridge) or two strain gauges (half bridge) are also available.[citation needed] The electrical signal output is typically

in the order of a few millivolts and requires amplification by an instrumentation amplifier before it can be used. The output of the transducer is plugged into an algorithm to calculate the force applied to the transducer.

Although strain gauge load cells are the most common, there are other types of load cells as well. In industrial applications, hydraulic (or hydrostatic) is probably the second most common, and these are utilized to eliminate some problems with strain gauge load cell devices. As an example, a hydraulic load cell is immune to transient voltages (lightning) so might be a more effective device in outdoor environments.

Other types include piezoelectric load cells (useful for dynamic measurements of force), and vibrating wire load cells, which are useful in geomechanical applications due to low amounts of drift.

Every load cell is subject to "ringing" when subjected to abrupt load changes. This stems from the spring-like behavior of load cells. In order to measure the loads, they have to deform. As such, a load cell of finite stiffness must have spring-like behavior, exhibiting vibrations at itsnatural frequency. An oscillating data pattern can be the result of ringing. Ringing can be suppressed in a limited fashion by passive means. Alternatively, a control system can use an actuator to actively damp out the ringing of a load cell. This method offers better performance at a cost of significant increase in complexity.

Load cells are used in several types of measuring instruments such as universal testing machines.[1]

Load Cell types based on working principle

Cantilever or bending beam Compression Tensile Universal Shear Torque HollowLoad Cell types based on construction

Bending beam Parallel beam or Binocular Beam Canister Shear beam Single column Multi-column Pancake Load button Single ended shear beam Double ended shear beam "S" type Inline rod end Digital ElectroMotive Force Diaphragm/membrane Torsion ring Bending ring Proving ring Load PinLoad Cell types based on electrical properties

Resistive Piezoelectric Capacitance Analog Digital WirelessApplications

Force measurement Portable weigh scales Platform scales Electronic weighbridge or truck weighing Electronic crane scales Hopper/Tank/Silo weighing Finding Center of gravity Onboard weighing Railcar weighing Structural health monitoring In-motion dynamic weighing check weigher Batch weighing Monitor inventory Feedback control Impact measurement Force gauge

Products & Services

Electronic Counter Scales

Electronic Platform Scales

Mechanical Platform Scales

Electromechanical scales