Patents by Inventor Philip W. Dudley

Philip W. Dudley 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).

  • Control system
    Patent number: 4226558
    Abstract: A control system for a hydraulically powered self advancing mine roof support, which system ensures that a hydraulically extensible chock leg of the support is set to a predetermined pressure, irrespective of the length of time that a main inlet valve is held open comprises an auxiliary valve interposed between a main valve and a chock leg(s) in a fluid supply line extending from a high pressure line to the support, a bypass line connected to the high pressure line in advance of the main valve and extending to the auxiliary valve, the auxiliary valve being so constructed as to open upon sensing a predetermined pressure and to close upon sensing a higher predetermined pressure.
    Type: Grant
    Filed: February 16, 1979
    Date of Patent: October 7, 1980
    Assignee: Fletcher Sutcliffe Wild Limited
    Inventors: Lewis R. B. Bower, Philip W. Dudley, John C. Smith