Patents by Inventor Calvin Franklin Mathis

Calvin Franklin Mathis 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).

  • Secure swing gate system that provides free access when power is off
    Patent number: 5771636
    Abstract: A swing gate providing free access when the electrical power that drives a hydraulic system to open and close the gate is off is described. The hydraulic system comprises a reversible electrical motor to drive a hydraulic pump which in turn provides hydraulic fluid under pressure to a double acting hydraulic actuator. An electrical actuated solenoid valve is located in a bypass line of the hydraulic system and the solenoid valve is designed to open when the electrical power is off which allows the hydraulic fluid to drain from one side of the actuator into a reservoir. Since one side of the double acting actuator contains no fluid under pressure, the swing gate can be opened by hand.
    Type: Grant
    Filed: April 10, 1996
    Date of Patent: June 30, 1998
    Inventor: Calvin Franklin Mathis