Improvements relating to flexure stays in weighing apparatus

931,355. Weighing apparatus. W. & T. AVERY Ltd. March 2, 1962 [March 8, 1961], No. 8383/61. Class 143. A flexure stay incorporated in weighing apparatus comprises interconnected flexure elements extending over similar but oppositely convexly curved support surfaces so that during angular movement of the stay the flexure elements are respectively wound on and off the support surfaces by equal amounts to maintain a substantially constant gauge length. In Fig. 1, the flexure stay is a single length of metal ribbon 10 and 11, 12 are the curved supports. The flexure stay 10 forms one side of a parallelogram, the opposite side being a lever 23 and the two other, opposite, sides being a vertical frame member 15 and a leg bracket 20. 22 and 24 are pivots. The load to be weighed is placed on a limb 21 extending horizontally from the bracket 20 and as it descends the limb 21 remains horizontal owing to the parallel arrangement. The end part 10b of the ribbon is unwound from its support surface and the other end 10a is wound on to its support surface by the same amount, the bending and unbending parts 10a, 10b constituting flexure elements. Since bending strain is less localized the use of early fatigue is reduced. In Fig. 3 the flexure stay is a strut member 30 and the flexure elements are constituted by metal ribbons 33,- 34 secured to the ends of the strut and wrapped round curved support blocks 36, 37. For incorporation in a lever system which is loaded so that the stay 40, Fig. 6, supports both tensional and compressive forces, two pairs of ribbons 41, 42 and 43, 44 are fastened to the stay, the ribbons 42, 44 extending inwards and wrapped round cylindrical support blocks and the ribbons 41, 43 extending outwards and wrapped round the blocks, compression then being resisted by the outer ribbons 42, 44 and tension by the inner ribbons 41, 43. At least one support surface may be angularly adjustable to adjust the gauge length of the stay.