Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01G—WEIGHING
  • G01G21/00—Details of weighing apparatus
  • G01G21/23—Support or suspension of weighing platforms
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
  • G01L1/00—Measuring force or stress, in general
  • G01L1/26—Auxiliary measures taken, or devices used, in connection with the measurement of force, e.g. for preventing influence of transverse components of force, for preventing overload

Definitions

• This invention relates to load supports or force transmission devices, suitable for use in weighing apparatus of various kinds, and which may find applicati in other areas as well.
• Such a device is provided by the present invention, which broadly resides in a load support comprising a load receiving member and a base member connected together by elastomeric material, characterised in that a force transmitting element is provided extending between said members and in free contact with at least one of said members.
• Fig. 1 shows in lateral cross-section, a load suppo embodying the present invention
• Fig. 2 is a plan view of the load support of Fig. 1
• Fig. 3 shows in lateral cross-section, a load suppo according to a second embodiment of the invention
• Fig. 4 is an underneath plan view of the load suppo of Fig. 3;
• Fig. 5 is a lateral cross-section of a load support according to a further embodiment of the invention
• Figs. 6 and 7 are lateral cross-sections of load supports according to still further embodiments of the invention
• Fig. 8 is a lateral cross-section taken at right angles to that of Fig. 7
• Fig. 9 is a plan view of an " embodiment of the invention incoporating three force transmission elements
• Fig. 10 is a cross-sectional elevation taken on the line 10 - 10 of Fig. 9.
• a load support device for receiving a load and transferring the load force to a load cell or other weighing device.
• the support illustrated in Figs.l and 2 comprises a bas member 10 which may be of steel or other rigid material a load-receiving plate 11 of similar material. Extendi between the base 10 and the plate 11 and bonded to both a body of elastomeric material which may for example be natural rubber or a synthetic rubber such as polyuretha
• a force transmittin element 13 in this case in the form of a boss extendin upwardly from the base 10, and provided with a rounded, part-spherical end on which the plate 11 rests.
• the ba 10 is provided with mounting holes 14, and the plate 11 provided with mounting holes 18.
• the rigid element 13 will transmit to the base 10 the vertical force due to a load placed on the plate 11, wh is however free to accommodate movement arising from distortion of the apparatus or arising from thermal expansion or contraction, without affecting the force transmitted to the base.
• the elastomeric body 12 will provide an elastic response to forces applied between t plate 11 and base 10 in directions other than the verti the plate 11 in response to such forces being free to t in any direction, and the plate 11 may move horizontall over the element 13 in response to horizontal forces su as may arise, for example, from expansion or contractio the associated apparatus.
• the elastomeric bod is not required to carry the applied load, as this is transferred to the base by the relatively rigid element In this way damage to the body 12 arising from internal shear as the side walls of the body bulge outwardly und load, is prevented.
• the properties of the elastomer can be chosen with greater freedom to suit the requirements of a particular application, and general the elastomer may be softer than would be required in the prior art.
• stiff load transfer element 13 Another advantage flowing from the use of the stiff load transfer element 13 is that it largely eliminates compression of the support in the direction of the load force. Supports capable of significant compression in this direction may in some situations lead to oscillation of the load and consequent damage or danger.
• a bas 10 is attached to a load receiving plate 11 by a polyurethane body bonded to each, and a boss 13 again transfers the load force to the base 10, but in this embodiment the base 10 includes a thin central section 15 on which are mounted two pairs of strain gauges 16 and 17
• the gauges 16 are mounted on the inner portion of the low surface of the section 15, which portion is placed in tension by the downward deflection of the centre of the base, while the gauges 17 are placed on the outer portion of this surface, which is placed in compression by such deflection.
• the gauges 16 and 17 may therefore be used in a bridge circuit to enable the applied load to be measure in known manner.
• the load receiving plate 11 is in free contac with the force transmitting element 13, substantially isolating the strain gauges 16 and 17 froir the effects of extraneous forces or movements of the plate 11.
• a combined support and strain guage assembly of the kind illustrated in Figs. 3 and 4 may be provided at each leg a tank support stand, the combined outputs of the strain gauges providing a measure of the weight of the contents the tank.
• the simplicity of this arrangement is most attractive, the weight of the tank being taken by the elements 13, while the lateral movement of the tank is restrained by the shear strength of the elastomeric bod and its adhesion to the plate 11 and the base 10. Alth additional lateral restraint may be provided, this will not normally be required.
• the configuration of load receiving plate and the end of the force transmitt element on which it rests are such as to allow the plat tilt about any axis normal to the direction of the appl load.
• the degre of freedom given to the plate are restricted.
• the force transmit element is fixed to the base.
• th force transmitting element is in free contact with the base, and allows freedom of movement of the base 10 as as the plate 11. Examples of such configurations will be described.
• the element 13 consists of a steel ball in fr contact with both the plate 11 and the base 10
• the element 13 consists of a steel pin with tape ends, again in free contact with both the load receivin plate and the base.
• the load receiving pl is given the maximum possible degrees of freedom.
• the ele 13 consists of a rectangular steel plate with tapered up and lower edges, and therefore allows tilting rotation o the plate 11 or the base 10 about one axis only.
• Figs 9 and 10 there is illustrated a load support with three elements 13, which will allow only lateral sliding movement of the plate 11 and the base 10. Clearly where two such elements are employed, tilting about one axis wi be possible.
• the manner of this engagement will be chosen to suit the application for the device, but will always provide at least one degree of freedom of movement of the plate or the base relative to the force transmitting element while maintaining force- transmitting contact. This may be a rotational movement, or a lateral movement, and such configurations are generically referred to herein by the requirement that th force transmitting element be in free contact with the member in question.
• the elastomeric material may be fixed to the load receivi member and to the base by any suitable means providing sufficient strength for the purpose at hand.
• the preferred method is thoroughly clean the surfaces of the load receiving member and the base and to fill the space between them in a gravity or pressure mould, subsequently curing the polyurethane in situ and thereby achieving a strong bond with the load receiving member and the base.
• the expressions 'elastomer' and 'elastomeric' are used in a general sense to include bot natural and synthetic substances or mixtures of those, o devices, which exhibit elastic or resilient ⁇ behaviour an are sufficiently flexible for the purpose.
• the opposed surfaces of the base and the lo receiving member may be provided with formations such a steps, grooves, peripheral flanges or other features to increase the lateral strength of the assembly.
• the elastomeric material is preferably moulded ab the force transmitting element and is in a single body, there may be applications where alternatives are preferable, and the elastomer may, for example, be provided in several separate bodies beiweent the load receiving plate and the base.
• T plate 11 may, for example, be provided with a pin for engagement within an aperture in the load structure, or with apertures for bolts or other fasteners.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Measurement Of Force In General (AREA)

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• 1988
  • 1988-03-11 EP EP19880902368 patent/EP0305452A1/de not_active Withdrawn
  • 1988-03-11 WO PCT/AU1988/000065 patent/WO1988007177A1/en not_active Application Discontinuation

Non-Patent Citations (1)

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