Abstract: Process for producing from a rubber mixture blanks for finished parts in the rubber industry is composed of an extruder having a cylinder and a screw rotatable in the cylinder to plasticize a rubber mixture fed into the cylinder, an extrusion head and a gear pump between the extruder and the extrusion head for producing extrusion pressure and forcing the mixture through the extrusion head at a predetermined rate per unit time to form a uniform strand of predetermined shape which is cut into uniform lengths.

Abstract: Rubber scrap is pulverized by feeding it into a gap between a parti-cylindrical recess in a block and a cylinder rotating in the recess. A plurality of blocks are mounted one above another in a first frame, and a like plurality of cylinders are mounted in a second frame. The blocks are so arranged that rubber scrap pulverized in the recess of one block is fed into the recess of the next lower block for further pulverizing. All of the cylinders are driven in rotation by a single motor through a belt or chain drive. A hydraulic cylinder piston unit is provided for raising the first frame relative to the second frame and thereby varying the gaps between the cylinders and the respective recesses of the blocks.