| 摘要 |
<p>1490987 Revolution-direction indicators WESTINGHOUSE BRAKE & SIGNAL CO Ltd 28 Feb 1975 [8 March 1974] 10503/74 Heading G1K [Also in Division B7] Apparatus for determining the direction of rotation of a disc 10 comprises two magnets 12, 13 attached diametrically to the disc, and two fixed reed switches 14, 15, the relative dimensions being such that with rotation of the disc each magnet produces in sequence operation of a first switch only, then both switches, then the second switch only and then neither switch. Pulses produced by the switches are fed through gates 16, 17, 18 to flip-flops 21, 22, 23 only one of which produces a logic 1 output for clockwise rotation, whereas two produce logic 1 outputs simultaneously for anticlockwise rotation. This is sensed by logic circuit 25 to produce a corresponding indication at 26. The apparatus may be employed on a train, using a toothed disc 10 on a wheel axle, and logic circuit 25 causes the brakes to be applied when the axle rotates for half a revolution in the reverse direction.</p> |
