Position Maintaining Type Patents (Class 91/390)
  • Patent number: 3938770
    Abstract: The present invention provides a simple and effective method and apparatus for hydraulically suspending a vehicle seat while regulating movement of the seat in response to vertical travel of the vehicle, a reciprocable power piston within a cylinder comprising a flexible coupling between the seat and a suitable support structure, a control valve selectively communicating a source of fluid with the cylinder in response to pressure variations developed by movement of the power piston within its cylinder. The invention also preferably includes load compensating means for limiting the control function in response to relatively minor movement of the piston as well as a damped leveling unit partially formed by the power piston for providing hydraulic response to limited movement of the piston.
    Type: Grant
    Filed: October 7, 1974
    Date of Patent: February 17, 1976
    Assignee: Caterpillar Tractor Co.
    Inventors: Leland D. Turner, Donald L. Smith