Patents by Inventor John C. Thornton

John C. Thornton 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 exercise apparatus having a main cylinder and a displacement cylinder
    Patent number: 5250015
    Abstract: A hydraulic exercise apparatus having an elongated frame housing a main hydraulic cylinder and a displacement cylinder in liquid communication with the main hydraulic cylinder. The main hydraulic cylinder includes a main piston and the displacement cylinder includes a closure piston that is movable in response to movement of the main piston to maintain a liquid filled condition in the main cylinder regardless of the position of the main piston.
    Type: Grant
    Filed: September 21, 1992
    Date of Patent: October 5, 1993
    Inventor: John C. Thornton