Patents by Inventor Dieter Hoffarth

Dieter Hoffarth has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4439041
    Abstract: A feed bushing for single-screw extruders for the plasticizing extrusion of plastics under a high inertia resistance comprising an outer casing, a grooved bushing enclosed in the outer casing, and a cooling system. The groove bushing is assembled from a tubular grooved inset and a tubular reinforcement surrounding the grooved inset, the inset being shrink-fitted into the reinforcement with such a high shrinkage allowance that the inset is prestressed for pressure by the reinforcement for withstanding the maximum forces of inertia of the screw received in the grooved bushing. The grooved inset of the grooved bushing is made of cemented carbide, a metal oxide or other extremely hard and wear-resistant material. The reinforcement element is made of high-strength ductile steel.
    Type: Grant
    Filed: April 2, 1982
    Date of Patent: March 27, 1984
    Assignee: Paul Kiefel GmbH
    Inventors: Gerard Schaeffer, Dieter Hoffarth