| 摘要 |
A material engaging apparatus, such as a press brake or shear, has first and second jaw members pivotally mounted together and with coordinating material engaging and working members in the jaw members. An extensible ram positioned along and between the rear sides of the jaw members has one end pivotally mounted to the second jaw member and another end pivotally mounted to a rear end of a lever arm extending from front to rear and spaced adjacent the first jaw member. A front end of the lever arm is pivotally mounted to a front end of the first jaw member. A connecting link extending between the first and second jaw members has a first end pivotally mounted to the lever between the front and rear ends thereof and a second end pivotally mounted to the second jaw member. The connecting link acts as a movable fulcrum for the lever arm and is movable therewith to provide substantially constant leverage as the lever arm moves to urge the first and second jaw members together.
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