GB1369590A - Torque meters - Google Patents

Abstract

1369590 Photo-electric torque measurement DUNLOP HOLDINGS Ltd 16 Nov 1971 [19 Nov 1970] 54954/70 Heading G1A A photo-electric torque measuring arrangement of the type comprising two slotted interrupter discs 4, 5 mounted at two positions, on a torque sensing shaft or structure, between which there may exist a torque, each disc repetitively interrupting light from a source 14, 15 directed at a photo-detector 12, 16, is modified so as to be able to measure torque at low or zero shaft velocity, by the addition of scanning discs 7, 8, movable in a direction opposite to that of discs 4, 5, in the light paths to introduce further interruption of the beams. The holes in discs 7, 8 may be spaced apart a larger distance than the slots of discs 4, 5, e.g. a multiple of the spacing of the slots, or an equal distance. When the spacings are similar the hole diameters should be narrower than the slots spacing to prevent a continuous beam of light reaching a photo-cell. The latter is associated with a reflecting cone so as to have a rectangular field of view which overlaps a number of slots of an interrupter disc. The scanning discs 7, 8 are rotated by the same motor or two synchronized motors. The outputs of the cells feed a phase sensitive frequency meter which monitors any phase difference in these outputs. A calibration procedure for the arrangement is described. Alternatives In Fig. 4 (not shown) instead of a single shaft bearing interrupter discs, the system is applied to two coupled shafts. A further arrangement, Figs. 5, 6 (not shown) has interrupter and scanning discs provided with a plurality of rows of slots and holes to give multi-range processing facility. Overload protection dogs are provided. A single light source may be used instead of the two 14, 15. It is stated that other forms of energy apart from light may be used with appropriate detectors.