Apparatus to manipulate workpieces

摘要

Workpieces are manipulated between the receiving position and the discharge position by supporting gripper arms on a platform mounted on a pivot shaft. The pivot shaft pivots between a position where a workpiece is gripped by one or more moveable gripper arms through a pivotal discharge position where the workpiece is released by the gripper arms. The pivot shaft is moved horizontally by a threaded adjusting screw toward and away from a vacuum chuck in a silk-screen printing machine to compensate for changes to the length of the workpiece to be carried by the vacuum chuck. This allows conveyors to remain at fixed elevations and merely change the site at which the workpieces are picked up in the case of a loading mechanism from a feed conveyor and the site where workpieces are deposited on a conveyor for an unloading operation.