Machines for handling or working materials in laminar or sheet form

A platen press comprising a fixed upper platen;

• a movable lower platen adapted for movement towards and away from said fixed upper platen;
• a feeder element comprising a plurality of nipper bars adapted for movement between said platens to remove sheet materials from between said platens;
• a crankshaft;
• a plurality of cranked levers articulated to said movable lower platen;
• a plurality of connected rods, each of said connecting rods respectively articulated to said crankshaft and articulated to one of the said cranked levers;
• and
• means for cyclically driving said crankshaft at variable speed, said means comprising a wheel adjacent to one end of said crankshaft, said wheel rotating about an axis parallel to the axis of said crankshaft, said wheel having a radial guide on a side of said wheel facing said one end of said crankshaft, a follower member connected to said one end of said crankshaft and slidably meshing with said radial guide of said wheel, the interaction between said radial guide on said wheel and said follower member producing a variable drag therebetween which, as it varies, changes the speed of rotation of said crankshaft which in turn drives said movable lower platen at variable speeds in an up and down movement by means of said plurality of connecting rods and said plurality of cranked levers, said crankshaft connected to said movable lower platen such that when said movable platen is closest to said fixed platen and said follower member is in its radially outermost position in said radial guide, said movable platen moves relatively faster than when said movable platen is farthest from said fixed platen and said follower member is in its radially innermost position, and during each rotation of said crankshaft about its axis, for about 270.degree. of said rotation said movable and said fixed platens are apart, and for about 90.degree. of said rotation said movable and said fixed platens contact each other, the movement of said movable lower platen being adjustable to the movement of said feeder element.