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Ratchet-type lever mechanism for seat lifter

  • US 6,666,423 B1
  • Filed: 05/31/2002
  • Issued: 12/23/2003
  • Est. Priority Date: 05/31/2002
  • Status: Active Grant
First Claim
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1. In combination with a seat lifter means which is subjected to upward motion and downward motion, respectively, in response to a normal first rotation of an operating lever and a normal second rotation of the operating lever opposite to the normal first rotation, in which the seat lifter means includes:

  • a brake means having a shaft operatively connected therewith, said brake means being adapted to provide a braking action to the upward and downward motions of the seat lifter means and being rotatable in one of a first direction and a second direction opposite to the first direction; and

    a transmission mechanism operatively connected between said brake means and said seat lifter means, said transmission mechanism requiring a reverse rotation of said operating lever to cause said upward and downward motions of the seat lifter means in contrast to said normal first and second rotations of the operating lever, wherein rotation of the shaft of said brake means in said first direction is converted via said transmission mechanism into said downward motion of the seat lifter means, whereas rotation of the shaft of said brake means in said second direction is converted via said transmission mechanism into said upward motion of the seat lifter means,a ratchet-type lever mechanism comprising;

    a first ratchet gear wheel means rotatably provided about said shaft of said brake means;

    said first ratchet gear wheel means being so designed to be rotatable together with the shaft of the brake means only when the shaft of the brake means is rotated in said first direction;

    a second ratchet gear wheel means rotatably provided about said shaft of said brake means;

    said second ratchet gear wheel means being so designed to be rotatable together with the shaft of the brake means only when the shaft of the brake means is rotated in said second direction;

    a shaft means rotatably disposed in a spaced-apart relation with the shaft of the brake means;

    said shaft means being connected with said operating lever such that a center of rotation of the operating lever is at a central axis of the shaft means;

    a ratchet gear means operatively provided between said shaft means and said first and second ratchet gear wheel means, said ratchet gear means including;

    a sector gear means for transforming said reverse rotation of the operating lever required by said transmission mechanism into one of said normal first and second rotations of the operating lever, to thereby cause the shaft of the brake means to rotate in same direction as one of said normal first and second rotations of the operating lever, so that the normal first rotation of the operating lever causes the shaft of the brake means to rotate in the first direction, whereas the normal second rotation of the operating lever causes the shaft of the brake means to rotate in the second direction, said sector gear means having, defined circumferentially thereof, a first arcuate gear means and a second arcuate gear means in such a manner that said first arcuate gear means is defined in an offset relation with said second arcuate gear means with respect to a center of said ratchet gear means, with such an arrangement that, when said operating lever is positioned in a non-use position;

    said ratchet gear means is normally positioned in a neutral point where the first and second arcuate gear means are out of engagement with said first and second ratchet gear wheel means, respectively, and that, when said normal first rotation of the operating lever is effected from said non-use position to cause said upward motion of said seat lifter means, said ratchet gear means is rotated to bring said first arcuate gear means to meshed engagement with said first ratchet gear wheel means, whereas, when said normal second rotation of the operating lever is effected to cause said downward motion of said seat lifter means, said ratchet gear means is rotated to bring said second arcuate gear means to meshed engagement with said second ratchet gear wheel means; and

    a base support means on which said shaft of said brake means is mounted;

    wherein said shaft means associated with said operating lever and said sector gear means are all rotatable supported on said base support means as one unit, and wherein the normal first rotation of said operating lever from said non-use position brings said first arcuate gear teeth to meshed engagement with said first ratchet gear wheel means, thereby causing rotation of said shaft of said brake means in said first direction so as to cause said upward motion of said seat lifter means via said transmission mechanism, whereas the normal second rotation of said operating lever from said non-use position brings said second arcuate gear teeth to meshed engagement with said second ratchet gear wheel means, thereby causing rotation of said shaft of said brake means in said second direction so as to cause said downward motion of said seat lifter means via said transmission mechanism.

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