Patents by Inventor Robert Albert Melcher

Robert Albert Melcher 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).

  • Apparatus for injection molding of bodies with a core and skin of different materials
    Patent number: 3947175
    Abstract: Injection molding apparatus for discontinuous fabrication of molded bodies consisting of a plurality of layers with a foaming core and an outer skin of non-foaming thermoplastic material, the apparatus consisting of an injection head connected to two extruders and equipped with a centrally-located jet surrounded by a ring jet.
    Type: Grant
    Filed: December 7, 1973
    Date of Patent: March 30, 1976
    Assignee: Siemag Siegener Maschinenbau GmbH
    Inventor: Robert Albert Melcher
  • Injection molding apparatus
    Patent number: 3937447
    Abstract: The invention is concerned with an injection molding apparatus in which thermoplastic material mixed with an expanding agent is kept in a plastic state below the reaction temperature of the agent and is passed generally continuously through an inter-connecting passage to a transfer cylinder; by flowing through the passage, the mass is heated above the reaction temperature and the built-up pressure prevents foaming of the thermoplastic until it is injected into a mold.
    Type: Grant
    Filed: September 7, 1973
    Date of Patent: February 10, 1976
    Assignee: Siemag Siegener Maschinenbau GmbH
    Inventors: Dieter Alwes, Helmut Eckardt, Hans Peter Leiste, Robert Albert Melcher