| 摘要 |
947,295. Sequential switching systems. WELDSTRON CORPORATION. May 30, 1962 [June 8, 1961], No. 20879/62. Heading H2H. An arrangement for stopping a machine when one of a number of operations performed in continuous cycles is faulty, comprises a cam switch 22, closed prior to the start until nearly the end of each cycle which holds on through a transistor 24a a transistor 28a, and through b-istable circuits 32, 36 locks transistor 36a on, which would otherwise block transistor 28a. A transistor 34 also resets circuits 38, 40 through conductor 48. As each operation is completed switches 16a-16c which may be of any type, i.e. limit, contact, photo-electric, &c. are closed, thus turning on transistors 40a, which through resistors 41a- 41c form a coincidence circuit on transistor 42a to block it, which switches bi-stable circuit 36 over, so that transistor 28a remains conductive when contact 22 opens. If any operation is not completed, one or more switches 16a-16e are not closed and transistor 42a remains conductive, hence bi-stable circuit 36 is not switched over, hence when contact 22 is opened transistor 28a is blocked which switches off the machine through relays 30, 30<SP>1</SP> and reverses indicator lamps 30c, 30f. Liquid-controlled indicator lamp 56 is connected to each bistable circuit 40 and is illuminated when contact 16 is closed, hence indicating which part of the machine requires attention. A reset button 58 restores the circuit to normal.
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