Patents by Inventor Wen-Jei Yang

Wen-Jei Yang 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 a foamed resin product having a smooth surface involving surface heating of the mold by applying high current low voltage electric power
    Patent number: 4496131
    Abstract: The invention comprises a method and apparatus to quickly heat a mold cavity surface or portions thereof just prior to the injection of a foamable plastic resin. The apparatus comprises one or more thin metal surface sheets or bands of high electrical resistivity in the mold cavity covering those portions of the mold where a smooth surface finish on the product is desired. In an alternative form the surface sheets may be plated or sprayed metal of high resistivity on a layer of thin electrically non-conducting plastic in turn adhered to the mold cavity surface.The thin metal surface sheet is resistance heated approximately 300.degree. F. in a few seconds or less by a low voltage high current source of electric power just prior to the injection of the foamable plastic. The high current passing through the metal of high resistivity causes conversion of electrical energy into sensible heat very quickly to accomplish quick heating of the mold cavity surface sheet.
    Type: Grant
    Filed: May 25, 1983
    Date of Patent: January 29, 1985
    Inventor: Wen-Jei Yang
  • Method of injection molding a foamed resin product having a smooth surface involving surface heating of the mold by applying high current low voltage electric power
    Patent number: 4390485
    Abstract: The invention comprises a method to quickly heat a mold cavity surface or portions thereof just prior to the injection of a foamable plastic resin. The apparatus comprises one or more thin metal surface sheets or bands of high electrical resistivity in the mold cavity covering those portions of the mold where a smooth surface finish on the product is desired. In an alternative form the surface sheets may be plated or sprayed metal of high resistivity on a layer of thin electrically non-conducting plastic in turn adhered to the mold cavity surface.The thin metal surface sheet is resistance heated approximately 300.degree. F. in a few seconds or less by a low voltage high current source of electric power just prior to the injection of the foamable plastic. The high current passing through the metal of high resistivity causes conversion of electrical energy into sensible heat very quickly to accomplish quick heating of the mold cavity surface sheet.
    Type: Grant
    Filed: January 7, 1982
    Date of Patent: June 28, 1983
    Inventor: Wen-Jei Yang