GB1243334A - Improvements relating to weigh beams - Google Patents

Abstract

1, 243, 334. Weighing apparatus. DRIVER SOUTHALL Ltd. Dec. 5, 1968 [Sept. 6, 1967], No. 40707/ 67. Heading G1W. In a weighing device comprising a pair of beam members each having a load or resistant carrying portion 50, 58, the portions 50, 58 extend on the same side of fixed supporting fulcra 52, 59 of the beam members and are so inter-connected that deflection in one direction of one portion 50 causes deflection of the other portion 58 in the opposite direction. As shown, the portions 50, 58 form parts of two bell-crank levers each of which form part of a parallelogram linkage comprising a leg member 53 or 60 and a stay 55 or 62, the leg members 53, 60 being arranged to support load and weight pans 70, 71, respectively. The bell-crank levers may be inter-connected by a member 69 which is maintained in tension or, alternatively, a member (76) Fig. 6 (not shown), maintained in compression. Knife-edge bearings may be provided or, alternatively, in a further embodiment Figs. 3 and 4, (not shown) flexure strips may interconnect members of parallelogram linkages. Relative movement of the parallelogram linkages when the weighing device is subjected to a load may be damped by a dashpot (48) and detected by an optical arrangement comprising a mirror (49a) tiltably movable by flexure strips (38b, 43b) Fig. 7 (not shown), connected to the mirror and to the linkages or by a transformer having its windings attached to one linkage and its core attached to the other linkage or by photo-electric cells, reed switches, or capacitance or induction devices. The weighing resistant may be provided wholly by weights or at least partly by an adjustable tension spring arranged between the two linkages. At least one of the parallelogram linkages may be replaced by a simple beam.