Patents by Inventor Edward Douglas Hartley

Edward Douglas Hartley 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).

  • Oil ring design
    Patent number: 4053165
    Abstract: This invention relates to a piston ring having two ring elements and a spacer-expander the latter including a series of interconnected parts each comprising two pairs of inwardly directed limbs, the inner ends of which are in contact with and resiliently load the ring elements, and a spacer element which extends transversely to space apart the ring elements at the outer periphery.
    Type: Grant
    Filed: December 17, 1975
    Date of Patent: October 11, 1977
    Assignee: Hepworth & Grandage Limited
    Inventor: Edward Douglas Hartley