| 摘要 |
A self-compensating tensioner, particularly a self-compensating tensioner for use in a folder of a web offset printing press, includes a plurality of rollers designed to tension tapes. Each roller is mounted on a tensioner arm. The tensioner arms are mounted on a rotatable shaft via one-way clutches with a weight attached to each tensioner arm so that the center of mass of the tensioner arm is offset from the rotatable shaft. The force of gravity may therefore rotate the tensioner arm about the shaft, applying a minimum tension to the tape through the roller. A lever arm is connected to the shaft through an engagement clutch, with an actuator connected to the lever arm. When the actuator and the engagement clutch are activated, the lever arm can apply a torque to the tensioner arms through the shaft, thereby increasing the tension in the tapes to a working level. When the engagement clutch is deactivated, the shaft may rotate freely, allowing each tensioner arm to be independently moved for tape installation and replacement and further allowing each tensioner arm to reach an equilibrium and thereby apply equivalent tensions to the tapes.
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