Patents by Inventor Brad A. Meyerholtz

Brad A. Meyerholtz 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: 8813487
    Abstract: A hydraulic circuit for a vehicle includes a first loop that includes, in serial order, a first hydraulic pump, a first hydraulic line, a hydraulic motor and a second hydraulic line. A second hydraulic pump and a third valve control low pressure fluid from the second pump to the hydraulic motor casing. The low pressure fluid through the third valve maintains the motor pistons retracted when the motor is not being used. For actuating the motor, the third valve is actuated for disconnecting the second pump and relieving pressure from the motor casing. Low pressure is then provided to the first and second lines for extending the motor pistons. The first and second valves are then actuated for isolating the first and second lines from one another, and the first pump is used to power the motor. The first, second and third valves are advantageously solenoid cartridge valves.
    Type: Grant
    Filed: September 6, 2012
    Date of Patent: August 26, 2014
    Assignee: Terra Drive Systems, Inc.
    Inventors: Keith M. Mears, James E. Smith, Brad A. Meyerholtz
  • Patent number: 8276376
    Abstract: A hydraulic circuit for a vehicle having at least one selectively actuated hydraulic assist motor. The hydraulic circuit includes a first loop that includes, in serial order, a first hydraulic pump, a first hydraulic line, at least one hydraulic motor and a second hydraulic line. A second hydraulic pump and a third valve is used to control the flow of low pressure fluid from the second pump to the hydraulic motor casing. The low pressure fluid through the third valve maintains the motor pistons retracted when the motor is not being used. For actuating the motor, the third valve is actuated for disconnecting the second pump and relieving pressure from the motor casing. Low pressure is then provided to the first and second lines for extending the motor pistons. The first and second valves are then actuated for isolating the first and second lines from one another, and the first pump is used to power the motor. The first, second and third valves are advantageously solenoid cartridge valves.
    Type: Grant
    Filed: May 6, 2009
    Date of Patent: October 2, 2012
    Assignee: Terra Drive Systems, Inc.
    Inventors: Keith M. Mears, James E. Smith, Brad A. Meyerholtz
  • Publication number: 20100281860
    Abstract: A hydraulic circuit for a vehicle having at least one selectively actuated hydraulic assist motor. The hydraulic circuit includes a first loop that includes, in serial order, a first hydraulic pump, a first hydraulic line, at least one hydraulic motor and a second hydraulic line. A second hydraulic pump and a third valve is used to control the flow of low pressure fluid from the second pump to the hydraulic motor casing. The low pressure fluid through the third valve maintains the motor pistons retracted when the motor is not being used. For actuating the motor, the third valve is actuated for disconnecting the second pump and relieving pressure from the motor casing. Low pressure is then provided to the first and second lines for extending the motor pistons. The first and second valves are then actuated for isolating the first and second lines from one another, and the first pump is used to power the motor. The first, second and third valves are advantageously solenoid cartridge valves.
    Type: Application
    Filed: May 6, 2009
    Publication date: November 11, 2010
    Inventors: Keith M. Mears, James E. Smith, Brad A. Meyerholtz
  • Patent number: 5647211
    Abstract: A valve for controlling the flow of hydraulic fluid from a hydraulic pump to and back from a pair of hydraulic motors. The valve includes a selector spool for selectively energizing and de-energizing the motors. A pair of flow dividers each include a pair of flow divider spools which are slidingly longitudinally arranged. A pair of poppets, also longitudinally slidingly arranged, are located between the spools are selectively shifted in response to the hydraulic fluid flow and pressures within the motors. The spools and poppets longitudinally shift to equalize the pressure of the hydraulic fluid delivered to each motor and minimize loses. An override spool is selectively shiftable for bypassing the flow dividers and directly connecting the pump to the motors.
    Type: Grant
    Filed: March 6, 1996
    Date of Patent: July 15, 1997
    Assignee: Fluidrive, Inc.
    Inventors: Neil Harber, Brad Meyerholtz