| 摘要 |
1349822 Automatic control of tension SIEMENS A G 29 Feb 1972 [4 March 1971] 9188/72 Heading G3R In a system for transporting tape e.g. magnetic tape from one reel to another, buffer chambers are provided, each with two detectors, e.g. photo-electric, at different levels to define a central range of loop lengths, beyond which the appropriate reel is accelerated to restore the loop within the range, and within which light reel braking is applied, the braking being temporarily increased when reversal of the tape occurs within the braking range. In the logic circuit shown, AND gate 5 receives a signal when the tape loop is in the braking range, and a signal from each of bistable circuits 1, 2 and 3, 4, which are set by "wind" and "rewind" signals respectively, when the tape reverses. Thus gate 5 opens if the tape reverses in the braking range, to trigger monostable circuit 6 and provide increased braking by unspecified means via gate 7. The output of monostable circuit 6 is used to reset bistable circuits 1, 2 and 3, 4. |
