| 摘要 |
<p>1,164,495. Automatic control systems. BOWE BÍHLER & WEBER K. G. Sept. 29, 1966 [June 7, 1966], No. 43653/66. Heading G3R. To control the sag in a web 3, e. g. of paper, between a steady motion machine 1 such as an unwinder and one having a different motion such as a cutter 2, the average speed of one machine is controlled relative to that of the other by a system in which a counter 8 determines the difference between pulses produced per unit length of web at each machine. A count above or below zero is converted to an analogue voltage which controls thyristors in a rectifier bridge supplying the motor of one machine. If the count reaches a predetermined upper value an AND gate is enabled to pass pulses which affect the operation of the second or "reference" machine. The pulse generates each comprise a pair of switches actuated by rotating magnets and connected to the counter via a bi-stable circuit which eliminates the effect of contact bounce. Logic circuits are described Figs. 7-10 (not shown) incorporating delay devices to ensure correct counting if pulses arrive simultaneously from each source.</p> |
