×

Remote control system for earth working vehicle

  • US 4,776,750 A
  • Filed: 04/23/1987
  • Issued: 10/11/1988
  • Est. Priority Date: 04/23/1987
  • Status: Expired due to Fees
First Claim
Patent Images

1. In an excavator-type vehicle having a tool-supporting multiple boom structure and a working tool carried thereon, a plurality of hydraulic motors positioning respective parts of said boom structure and said tool, said motors having main control valves;

  • a pilot valve for each of said main control valves, each pilot valve being adjustable to alternate pressure and return between the respective pilot valves and the respective main control valves and for returning fluid from the main control valves through the pilot valves to sump;

    electrohydraulic valves in the lines between the pilot and main control valves, each being biased to one position permitting uninterrupted movement of fluid through said lines and shiftable to another position to block pressure from said pilot to said main control valves, each of said electrohydraulic valves, when in said another position, providing a pressure outlet in communication with a line between the respective electrohydraulic valve and a respective main control valve while retaining return of fluid through the respective pilot valve to sump;

    an electrical power source on said vehicle and associated control means for positioning the respective electrohydraulic valves;

    a pressure source in communication with each of said pilot valves and each of said electrohydraulic valves; and

    a selector valve selectively shiftable to block communication between the pressure source and said electrohydraulic valves.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×