GB1376445A - Weighing apparatus - Google Patents

Abstract

1376445 Weighing apparatus G H ROGER 6 July 1972 [25 June 1971] 29805/71 Heading G1W A spring-balance has the spring 30 mounted so that over a first range of movement from zero a greater length of the spring is employed than over subsequent range(s) of movement, so that the movement of a pointer 20 per unit increase in load is greater over the first range than over the subsequent range(s). In Fig. 1, a vertically movable member 14, guided by parallelogram links 27, 29 pivoted to a frame 24, supports a weighing pan 18 and is connected by a horizontal arm 35 to a rack 37 meshing a pinion 39 on the pointer shaft. The arm 35 is also connected at 32 to the lower end of a helical tension spring 30. The spring upper end is anchored to a crossmember 42 secured to a threaded tie-rod 36 by nuts 54. The tie-rod is supported on the frame 24 by a nut 38 for zero adjustment. A similar crossmember 56 is secured part way down the spring, to be freely slidable on the tie-rod 36. For the first range, up to 11b, the whole spring 30 is effective. At a load of 11b the cross-member 56 engages a stop 40 on the lower end of tie-rod 36, so that for higher loads, only the lower section of the spring, between 56 and 32, is effective. The members 42, 56 Fig. 6 comprise a tube 44, e.g. of nylon, with a 270 degree helical rib 48 to engage between turns of the spring. Recesses 50 facilitate manual adjustment. Fig. 7 and 8 (not shown) concern balances with load-suspension hooks 18 using the above tworange principal, that of Fig. 8 having two springs in parallel. Fig. 9 shows a balance using a compression spring 30. The stop 40 is adjustably secured to the tie-rod 36 on which the hook 18 is formed. At the end of the first range, the stop 40 abuts the cross-member 56, so that for higher loads only the lower portion of the spring, between 56 and 34, is effective.