Patents by Inventor Charles Heisig

Charles Heisig 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: 5351601
    Abstract: A hydraulic control system in which the flow of hydraulic fluid to and from cylinders on either side of a piston is controlled by normally closed check valves that are opened whenever a control valve is not in its neutral state. Float check valves respectively in series with the check valves and the check valves are opened when the control valve is in a neutral state by pressure from one of the cylinders so as to permit the load to move freely in response to external forces applied to it. A normally closed check valve is provided in which load sense pressures drive it open and pressure from a cylinder is balanced out. A cross check valve is such that the ratio of the areas for driving it open to the area for keeping it shut are at least 35:1.
    Type: Grant
    Filed: May 4, 1992
    Date of Patent: October 4, 1994
    Assignee: Control Concepts, Inc.
    Inventors: Kenneth W. Zeuner, Charles Heisig