Patents by Inventor John David Butler

John David Butler 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: 3939551
    Abstract: A method for manufacturing an oil seal element from polytetrafluoroethylene and the like. A tubular billet of polytetrafluoroethylene or the like is provided with an outer cylindrical surface of the desired diameter and an inner cylindrical surface approximating but slightly smaller than the desired diameter, and an end wall is faced off perpendicular to the cylindrical surfaces. A series of washers of a desired thickness is then sliced from the billet. The flat washer is then first assembled with a metal case and then a desired hydrodynamic shape, such as a spiral groove, is coined in. Preferably, the inner pierce is completed at this time. Each washer may then be formed under pressure to permanently deform the radially inner portion thereof to a frustoconical shape. The assembled seal may be held on a shaft-size mandrel during application of a coating to the metal case.
    Type: Grant
    Filed: February 4, 1975
    Date of Patent: February 24, 1976
    Assignee: Federal-Mogul Corporation
    Inventors: William E. Clark, John David Butler