GB915250A - Improvements relating to weighing machines - Google Patents

Abstract

915,250. Weighing apparatus. SALTER & CO. Ltd., GEORGE. Oct. 19, 1961 [Nov. 3, 1960], No. 37768/60. Class 143. In a personal weighing machine of the kind in which a platform 2 is floatingly supported on two overlapping lever plates 3, 4, fulcrumed on a base 1 so that the load is divided between them and in which the upper, main, lever plate 3 is attached to load springs 5 and its movement is transmitted, through rack-and-pinion 33, 34, to a rotatable dial 6, a bracket 20 from which the load springs 5 are suspended and bracket parts 36, 37 which form a bearing bar the pinion 34 are both carried on one of the lever plates, as shown, by the upper lever plate 4. The lower, main, lever plate 3 is fulcrumed on knife edges 8 and the upper lever plate 4 is fulcrumed on knife edges 81. The platform 2, which may be coupled to the base 1 through a spring 42, has depending lugs 13 with notches 14 whereby it is floatingly supported on the lever plates. The bracket 20 is of inverted U-shape and a horizontal plate 21 engages notches 22 in its sides. The load springs 5 are suspended from the end of a beam-like plate 18 which is convex at its middle part 25 so as to seat rockingly on the plate 21. By means of a screw 23 the plate 21 may be raised and lowered, so providing a zero-setting arrangement. The rack 33 is moved in correspondence with the movement of the outer end of the main lever plate 3 through a bell-crank lever, of which one arm 28 has a stirrup part 29 which rests on a projection 26 from the lever plate 3, Fig. 10, and the other arm 30 is jointed at 31 to a rack bar 32 extending from the rack. A tension spring 39 exerts an oblique pull on the rack bar 32 and thereby maintains the rack 33 in engagement with the pinion 34 and also keeps the stirrup part 29 in contact with the projection 26.