Patents by Inventor Larry E. Feldcamp

Larry E. Feldcamp 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).

  • Positive traction hydraulic drive system
    Patent number: 7100732
    Abstract: A hydraulic drive system includes a pair of hydraulic drive motors connected in series. Each motor includes a hydraulic circuit with a spring-biased directional control valve and a pair of check valves. The circuits are located in the end cover for each motor, and are in fluid communication with the respective motor and with each other. The circuits are responsive to the pressure differential across the motors, due to the load and direction of the vehicle, and direct flow to one wheel or the other. Flow is directed to the inside motor when accelerating and/or climbing, while the outside motor is allowed to turn freely to compensate for the different turning radius. This reverses when the vehicle is going downhill and/or decelerating, when the motors are braking. If the drive wheel loses traction, the flow and pressure shifts to the other wheel (or to both wheels), until traction is regained.
    Type: Grant
    Filed: August 13, 2003
    Date of Patent: September 5, 2006
    Assignee: Parker-Hannifin Corporation
    Inventor: Larry E. Feldcamp
  • Positive traction hydraulic drive system
    Publication number: 20040040774
    Abstract: A hydraulic drive system includes a pair of hydraulic drive motors connected in series. Each motor includes a hydraulic circuit with a spring-biased directional control valve and a pair of check valves. The circuits are located in the end cover for each motor, and are in fluid communication with the respective motor and with each other. The circuits are responsive to the pressure differential across the motors, due to the load and direction of the vehicle, and direct flow to one wheel or the other. Flow is directed to the inside motor when accelerating and/or climbing, while the outside motor is allowed to turn freely to compensate for the different turning radius. This reverses when the vehicle is going downhill and/or decelerating, when the motors are braking. If the drive wheel loses traction, the flow and pressure shifts to the other wheel (or to both wheels), until traction is regained.
    Type: Application
    Filed: August 13, 2003
    Publication date: March 4, 2004
    Inventor: Larry E. Feldcamp