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Lifting system for adjustable hospital bed

  • US 4,425,673 A
  • Filed: 12/01/1980
  • Issued: 01/17/1984
  • Est. Priority Date: 12/01/1980
  • Status: Expired due to Term
First Claim
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1. An adjustable hospital bed comprising:

  • a lower base frame having head and foot ends;

    a movable upper frame having head and foot ends;

    a head elevating linkage system interconnecting the head ends of said frames and operable to adjustably elevate the upper frame'"'"'s head end;

    a foot elevating linkage system interconnecting the foot ends of said frames and operable to adjustably elevate the upper frame'"'"'s foot end;

    independently rotatable head and foot drive screws mounted one to the side of the other on said upper frame for rotation about parallel axes that are fixed in position with respect to said upper frame;

    head drive means threadedly coupled to, and responsive to rotation of, said head drive screw for actuating said head elevating linkage system, rotation in one direction causing the upper frame'"'"'s head end to raise whereas rotation of said head drive screw in the other direction effects lowering of the upper frame'"'"'s head end;

    foot drive means threadedly coupled to, and responsive to rotation of, said foot drive screw for actuating said foot elevating linkage system, rotation in one direction causing the upper frame'"'"'s foot end to raise while rotation of said foot drive screw in the other direction effects lowering of the upper frame'"'"'s foot end;

    first means for rotating said head drive screw in a selected one of its two directions, said first means including a first gear that is mounted on and is capable of rotating relative to the head drive screw, and a first clutch for engaging the first gear with the head drive screw, so that the head drive screw will rotate in the direction that the first gear turns;

    second means for rotating said foot drive screw in a selected one of its two directions, said second means including a second gear that is mounted on and is capable of rotating relative to the foot drive screw and a second clutch for engaging the second gear with the foot drive screw, so that the foot drive screw will rotate in the direction that the second gear turns;

    the first and second gears forming part of a gear train and the first and second clutches being operable independently of each other or jointly;

    the direction of the threads on the head and foot screws and the arrangement of the gear train being such that when the head and foot screws rotate in unison, the upper frame will change elevation while maintaining substantially the same angle with respect to the base frame;

    and means coupled with the gear train for rotating the first and second gears in either direction of rotation;

    said elevating linkage systems thereby being operable independently of each other in order to facilitate positioning of said upper frame at any selected desired height and at any selected desired tilt angle and further being operable simultaneously such that the upper frame changes elevation while maintaining substantially the same angular disposition with respect to the base frame.

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