Patents by Inventor William A. Bridge

William A. Bridge 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).

  • Method and apparatus for tube extrusion
    Patent number: 4376621
    Abstract: Reduced breakage and reduced internal gas pressure is achieved in the trapped bubble process for the preparation of film by applying vacuum to the region of the tube where the bubble starts to form.
    Type: Grant
    Filed: May 22, 1978
    Date of Patent: March 15, 1983
    Assignee: The Dow Chemical Company
    Inventor: William A. Bridge
  • Method for the preparation of plastic film
    Patent number: 3989785
    Abstract: Film is prepared by a trapped bubble process. The inflated tube of plastic material is subsequently further expanded by trapped internal gas to provide a bubble and orientation of the film. Irregularities in the film are randomized by cyclic rotation of the tube and bubble with a rotating means having a variable speed drive.
    Type: Grant
    Filed: November 25, 1974
    Date of Patent: November 2, 1976
    Assignee: The Dow Chemical Company
    Inventor: William A. Bridge