| 摘要 |
To control the rotation of wire being fed from a reel, the tension of the wire is sensed by a pivotable arm which, through a valve system, controls operation of a pneumatic cylinder having a reciprocatable piston rod which coacts with a friction clutch. The rod in one position causes the clutch to brake the reel, in response to low tension, and in another position allows the reel to rotate freely, in response to a higher tension, and the rod is reciprocatable to impart accelerating pulses to the reel through the clutch in response to a still higher tension.
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