Flat bed type casting machine improvements

Claim 1

In a plate casting machine for casting plastic printing plates made from a thermosetting resin having exothermic characteristics during curing where said machine has a flat lower platen, an arm pivotable about a first hinge line extending parallel to a side of said lower platen, a flat upper platen hinged at one end to said arm along a second hinge line to open and close with respect to said lower platen with a clamshell-like motion, a matrix clamping frame associated with said lower platen to clamp the outer periphery of a matrix and to contain liquid resin thereon, power means for pivoting said arm about said first hinge line, and stop means for limiting movement of said arm about said first hinge line towards an upper platen closing position; the improvement comprising having in addition hydraulic motor means positioned on said arm and connected to said upper platen which upon the application of hydraulic force will pivot said upper platen about said second hinge line to the closed position with respect to said lower platen and valve control means for varying the rate at which said hydraulic motor will pivot the upper platen about said sEcond hinge line in order that the rate of engagement of the upper platen with liquid resin which has been flowed on one end of the matrix adjacent said first hinge line will not exceed the rate of advancing flow of said liquid resin over said matrix.