Patents Assigned to Siemag Siegener Maschinenbau GmbH
  • 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