| 摘要 |
757,105. Shaft-position signalling systems. IMPERIAL CHEMICAL INDUSTRIES, Ltd. Nov. 3, 1954 [Nov. 30, 1953; April 9, 1954], Nos. 33156/53 and 10478/54. Class 40(1) [Also in Group XL(b)] The movement of a shaft, e.g. of a weighing machine is measured by means operated by rotation of the shaft which produces a pulse pattern in which when the shaft is rotated in one direction a first pulse is produced in a first circuit and a second pulse is produced in a second circuit, the second pulse beginning before the first pulse ends so that it lags behind and partially overlaps the first pulse, the second pulse being followed by a time interval before the next pair of overlapping pulses is produced, and the pattern being reversed when the shaft is rotated in the opposite direction, pulses from the first circuit being applied to one guide of a polycathode counter tube, and pulses from the second circuit being applied to the other guide of the tube. As shown, the shaft 1 carries a transparent disc 2, which carries opaque radial markings 7 separated by transparent portions 6, co-operating with a lamp 3, a gate 4, and two photo cells at 5. The gate 4 has two sets of markings, comprising transparent portions 10 and opaque portions 11, and transparent portions 12 and opaque portions 13 respectively, a photo-cell being arranged behind each set of markings. By this means, each photocell produces a set of pulses, one set leading or lagging on the other according to the direction of rotation of the shaft. The pulses from the photo-cell V1 are amplified at V3, shaped at V5 and applied to the first guide G1 of the polycathode counter V7, the pulses from photo-cell V2 being similarly treated and applied to the guide G2, and according to which pulse of the overlapping pulse pairs reaches the counter V7 first, the counter is caused to add or subtract in known manner. The counter may be arranged to operate apparatus providing a printed record. Alternatively, the overlapping pairs of pulses may be produced electromagnetically by a moving conductive disc co-operating with with two stationary concentric zig-zag arrangements of conductive material, or electrostatically, the rotating member varying the capacity between it and two stationary members. |
