Mechanical plate clamp

A clamp for supporting a supported plate having a first side and a second side and an opening and a clamping area with a projected boundary on both said sides around said opening which comprises:

• a plate support means having a first clamping surface in contact with said clamping area on said first side;
• a segmented clamp means which comprises at least three segments and each segment comprises a flat segment plate having a straight beveled edge whose angle is complementary to an adjacent edge of a segment plate of a neighboring segment so that when said segments are withdrawn to said unloading position within said projected boundary, beveled edges of neighboring segments slide over one another so that said segment plates move to different planes thereby avoiding interference with one another and when said segment plates are in said clamping position, said adjacent beveled edges are in complementary contact with one another so that all the segment plates of all said segments lie in the same plane and wherein each said segment plate has attached to it an elastic band attachment means;
• a clamp positioning means which moves said segmented clamp means between said clamping position and said unloading position which comprises a flat bearing having a surface in contact with said segment plates and a rod having a cam on its surface and an elastic band attached to said band attachment means which maintains said segments in sliding contact with said cam so that when said rod slides axially, said segments are constrained by said bearing surface and said cam to move between said unloading position and said clamping position.