Universal holding fixture

Claim 1

A universal holding fixture for holding a workpiece having a fixture engaging surface, comprising: support means including a vacuum manifold; a plurality of adjustable workpiece engaging rods mounted to said support means for engaging the fixture engaging surface of the workpiece, said workpiece engaging rods being adjustable in height relative to said support means; means for adjusting the height of each workpiece engaging rod independently of the workpiece and relative to said support means so that said plurality of adjusted rods reproduces the contour of the fixture engaging surface of the workpiece; and means for generating a holding force for holding the workpiece in engagement with said rods, the holding force acting through said rods, wherein: said means for generating a holding force includes vacuum generating means connected to the vacuum manifold of said support means through which a vacuum, generated by said vacuum generating means, is communicated to each rod; and each workpiece engaging rod includes a stationary guide bushing having a longitudinal slot open to the vacuum in said vacuum manifold, and a support rod in said bushing displaceable in height from a retracted position by said adjusting means independently of the workpiece and relative to said guide bushing and the vacuum manifold, said support rod defining a free end situated externally of said vacuum manifold, said free end including a suction pad which engages the fixture engaging surface of the workpiece, said support rod further defining a passage terminating at one end at said pad and having an opening at its other end, said support rod passage being in communication with said manifold when said opening is aligned with said bushing slot when said support rod is not in its retracted position, and when said support rod is in its retracted position, said opening is not in alignment with said bushing slot, and said passage is not in communication with said manifold.