Patents by Inventor Erhard Schrode

Erhard Schrode 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: 4409169
    Abstract: A method for manufacturing high information density storage disks, suitable for optical reading, out of transparent synthetics having a high glass temperature and high dimensional stability. The present injection molding method avoids potential double diffraction disruptive effects created by frictional or shearing forces. The synthetic material which is to be pressed is injected into one of the mold halves at a temperature that significantly exceeds the pressing temperature of the compression form and is injected so as to form a lump of the material. The pressing step wherein the compression form is closed down to a squeezing gap width is initiated prior to the termination of the injection operation. Likewise the cooling operation is initiated prior to the termination of the pressing step and both the cooling and pressing operations chronologically proceed at approximately an exponential rate.
    Type: Grant
    Filed: July 21, 1981
    Date of Patent: October 11, 1983
    Assignee: Polygram GmbH
    Inventors: Dieter Bartholdsten, Hermann Koop, Erhard Schrode, Adelbert Zielasek