GB695755A - Improvements in strain gauges - Google Patents

Abstract

695,755. Electrical resistance type strain gauges. SAUNDERS-ROE, Ltd., and JACKSON, P. G. S. May 23, 1952 [June 20, 1950], No. 14625/51. Class 40 (i). A device for measuring tension forces Fig. 2 or compression and tension forces with the aid of a compression spring 33 Fig. 6 comprises a strain sensitive wire element 32 freely disposed in zig-zag formation between a pair' of spaced coaxial insulating discs 10, 11 enclosed by cups 29 and fast with metal shafts 12, 13 one of which 12 terminates as a spigot 15 and the other 13 as a co-operating socket 14 so that in use with the device suspended and loaded mechanically the discs 10, 11 move towards or away from another with greater or lesser interengagement between the spigot and socket 14, 15. The discs 10, 11 are prevented from relative rotation by spigot pins 16 engaging in axial slots 17 in the socket 14. In use the element 32 constitutes one arm of a measuring bridge and the device embodies as the adjacent arm a temperature compensating resistance wire 21 wound helically on a former made up of end rings 22, 23 joined by strips 24 which are bent over and secured to the disc 10. In a further embodiment Fig. 7 the sensitivity is doubled by making the apparatus comprise effectively two Fig. 2 or two Fig. 6 units so that a full bridge is formed. As shown Fig. 7 this is accomplished by introducing an intermediately placed insulating washer 34.