Patents by Inventor Fred H. Rojahn

Fred H. Rojahn 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: 4062919
    Abstract: A method for making a plastic, relatively flexible stringer for a slide fastener is disclosed. The stringer blank is extruded in a relatively rigid U-shaped form and, subsequently, a plurality of longitudinally spaced, transverse slots are die cut in the stringer blank in order to provide a series of transverse, substantially parallel ladder-like portions wherein each of the ladder-like portions includes an interlocking head member. A plurality of longitudinally spaced apart seats are also formed by a die cutting step in order to define neck portions of reduced thickness about which the stitches are placed in order to secure the fabric to the stringer.
    Type: Grant
    Filed: May 21, 1976
    Date of Patent: December 13, 1977
    Assignee: U. Zip International, S. A.
    Inventors: Fred H. Rojahn, Jose Lichtenberg
  • Patent number: 4037295
    Abstract: A stringer method for making a plastic, relatively flexible stringer for a slide fastener is disclosed. The stringer blank is extruded in a relatively rigid U-shaped form and, subsequently, a plurality of longitudinally spaced, transverse slots are die cut in the stringer blank in order to provide a series of transverse, substantially parallel ladder-like portions wherein each of the ladder-like portions includes an interlocking head member. A plurality of longitudinally spaced apart seats are also formed by a die cutting step in order to define neck portions of reduced thickness about which the stitches are placed in order to secure the fabric to the stringer.
    Type: Grant
    Filed: February 9, 1976
    Date of Patent: July 26, 1977
    Inventors: Fred H. Rojahn, Jose Lichtenberg