Patents by Inventor Derek C. Trethewy

Derek C. Trethewy 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 handling and filling bags or envelopes
    Patent number: 4393640
    Abstract: A method and apparatus for handling and filling bags or envelopes fed from a continuous length supply are disclosed wherein each bag or envelope is open at or adjacent one marginal edge of the continuous length supply for insertion thereinto of filling material.
    Type: Grant
    Filed: August 28, 1980
    Date of Patent: July 19, 1983
    Assignee: Hazelwood Enterprises Limited
    Inventors: Denis B. Cole, Derek C. Trethewy