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Automatic semi-trailer landing gear extension and retraction apparatus

  • US 4,097,840 A
  • Filed: 10/18/1976
  • Issued: 06/27/1978
  • Est. Priority Date: 10/18/1976
  • Status: Expired due to Term
First Claim
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1. In a tractor trailer rig of the type which includes a conventional tractor having an operator'"'"'s cab, a source of electrical power, and a fifth wheel hitch member;

  • a semi-trailer having hitch pin means on the forward end portion for engaging the fifth wheel hitch member, road wheels journaled on the rear end portion and an alternately extendable and retractable landing gear mounted intermediate the hitch pin means and the road wheels;

    the landing gear having gear drive means operatively engaged therewith which gear drive means includes an input drive shaft adapted to be engaged by a crank handle for manual rotation thereof in a first direction to extend the landing gear to engage the ground and support the semi-trailer independently of the tractor and, alternately, in a second direction to retract the landing gear from the ground engaging position to allow the forward end portion of the semi-trailer to be supported by the tractor with the hitch pin means engaging the fifth wheel hitch member;

    an improved automatic landing gear extension and retraction apparatus comprising;

    an electric drive motor mounted on the forward end portion of the semi-trailer and having a power output shaft;

    means for drivingly connecting the power output shaft to the input drive shaft of the gear drive means of the landing gear;

    position sensing means operatively connected to the landing gear for providing a first signal output when the landing gear is retracted and, alternately, for providing a second signal output when the landing gear is extended; and

    control circuit means mutually interconnecting the source of electrical power, the electric drive motor and the position sensing means, and responsive to external control thereof, for providing electrical power to the electric drive motor to rotate the input drive shaft in the first direction to extend the landing gear and, alternately, for providing electrical power to the electric drive motor to rotate the input drive shaft in the second direction to retract the landing gear.

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