Abstract: Apparatus for forming concrete building blocks which is constructed and arranged (1) to minimize sound emissions to the environment of a magnitude which might cause injury to the hearing of the operators, (2) to provide shielding around the major movable components of the machine so as to substantially eliminate potential causes of bodily injury to the operators, and (3) to improve the performance and cooperation of the major components for making concrete blocks. To provide shielding against noise and bodily injury, the frame of the apparatus is constructed in conjunction with sound insulation panels to provide an enclosure around the major movable components of the apparatus, and the frame also supports these components on internal surfaces thereof so as to minimize sound transmission openings to the environment.

Abstract: Method and apparatus for cleaning a tire curing mold by immersion in liquid cleaning agent bath, wherein the complete upper assembly of the mold is immersed in the bath and slowly rotated. Super or ultrasonic energy sources are particularly located and aimed, so that in combination with the relative motion of the mold assembly relative to the sources no portion of the surfaces to be cleaned is hidden by any other part from the direct impingement thereon of the sound wave energy. Efficiency of mold cleaning is materially advanced.

Abstract: Ejecting means, in a slot die head to extrude plastic material in a strip, whereby material left in the slot die head after extrusion has ceased can be removed, comprising a piston mounted with its crown flush with the inner wall of a distributing passage in the slot die head, so that, after the slot die head has been opened by separately upper and lower parts thereof, the piston can be moved hydraulically to project into the distributing passage to lift the residual material away from the wall of the distributing passage containing the piston to facilitate grasping of the material by an operator and stripping from the slot die head.

Abstract: Accumulated deposits are removed from the face of a spinneret by periodically manually wiping the face of the spinneret with the blade of a hand held wipe stick. Cooling the blade just before use decreases the smearing of the polymer melt and increases the wipe cycle. Dry ice is the preferred cooling medium.