| 摘要 |
A machine for advancing a strip of sheet metal in measured increments includes a main frame and subframes supported on transverse ways on the main frame so that the subframes may be moved toward and away from each other to vary the spacing between them. The subframes lie along a path that accommodates the sheet metal strip, and at their forward ends have fixed gripping units which clamp down on the strip to prevent it from moving in the path. The subframes have tracks along which movable gripping units move to and fro. The movable gripping units also have the capacity to clamp down on the strip. Each subframe also carries an endless chain which is driven by a hydraulic motor on the subframe to move the movable gripping unit for the subframe along its track. Basically, the movable gripping units alternately grip the strip and advance it, so that while one gripping unit is propelling the strip forwardly, the other is returning to its initial position to thereafter grip the strip and propel it. In the intervals between successive advances, the fixed gripping units clamp down on the strip and the strip is cut at a shear to provide panels of equal length. A hydraulic cylinder exerts a constant force on the chain that drives each movable gripping unit to maintain that chain taut. Each of the fixed and movable gripping units has a pair of pads along which it actually clamps against the metal strip. One pad of the pair lies in a pocket form which it is easily extracted to make room for removal of the other pad.
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