Patents by Inventor James A. F. Litherland

James A. F. Litherland 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).

  • Hydraulic seal with pressure-actuated ridges
    Patent number: 4557488
    Abstract: An elastomeric seal (1), particularly for mining roof supports, has a circumferentially extending primary sealing ridge (4) for sealing against the cylinder wall (15) at both low and high pressure differentials. In order to provide lubrication of the primary sealing ridge, a series of fluid reservoirs (10) are defined adjacent to opposite sides of the primary sealing ridge by a respective web (5) of secondary sealing ridges, each web consisting of a circumferential ridge (6) and a series of axial ridges (7).
    Type: Grant
    Filed: February 15, 1985
    Date of Patent: December 10, 1985
    Assignee: Hillman Newby Ltd.
    Inventor: James A. F. Litherland