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

• Current Assignee: Tachi-S Company Limited
• Original Assignee: Tachi-S Company Limited
• Inventors: Nemoto, Akira
• Primary Examiner(s): Braun, Leslie A.
• Assistant Examiner(s): Le, Tan
• Application Number:
  US10/157,830
• Publication Number:
  US 20030222193A1
• Time in Patent Office: 571 Days
• Field of Search: 248/421, 248/422, 248/396, 248/394, 248/397, 248/372.1, 297/344.15, 297/344.17, 297/344.12
• US Class Current: 248/421
• CPC Class Codes: B60N 2/1615 Parallelogram-like structure
• CPC Class Codes: B60N 2/165 Gear wheel driven mechanism
• CPC Class Codes: B60N 2/167 Ratchet mechanism

Abstract

A ratchet-type lever mechanism for seat lifter, which comprises a brake unit whose shaft is connected with a mechanism of the seat lifter, two ratchet gear wheels provided about the shaft of brake unit, a shaft rotatable in a spaced-apart relation with the brake unit shaft, an operating lever connected with the shaft, and a sector ratchet gear element provided between the operating lever and two ratchet gear wheels. The sector ratchet gear element is so arranged in the lever mechanism to enable a user to rotate the operating lever in usual way without confusion about direction of rotation of the lever to cause upward and downward motions of the seat lifter. The sector ratchet gear element may be of an outwardly-toothed type having two outwardly toothed arcuate gear teeth and two sector gear portions, or may be of an inwardly-toothed type having two inwardly toothed arcuate gear teeth.

Claims

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.

2. The ratchet-type lever mechanism as defined in claim 1, wherein a biasing means is provided about said shaft means so as to normally bias said operating lever toward said non-use position while normally biasing said ratchet gear means toward said neutral point.

3. The ratchet-type lever mechanism as defined in claim 1, wherein said first arcuate gear means comprises a first inwardly-toothed sector gear teeth and said second arcuate gear means comprises a second inwardly-toothed sector gear teeth, wherein said sector gear means comprises an inwardly toothed sector ratchet gear element having a sectorial ring body in which said first and second inwardly-toothed sector gear teeth are formed, and wherein said inwardly toothed sector ratchet gear element has:

a connection end portion with which said operating lever is connected; and

a securing portion defined between said sectorial ring body and said connection end portion, and wherein said securing portion is fixedly connected with said shaft means.

4. 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 require 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 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 first second ratchet gear wheel means being designed to be rotatable together with the shaft of the brake means only when 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; and

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 operation 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 his 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 mean, said ratchet gear means is rotated to bring said second arcuate gear means to meshed engagement with said second ratchet gear wheel means;

wherein said sector gear means comprises an outwardly toothed sector ratchet gear element including;

a shaft disposed between said shaft means and said shaft of said brake means;

a first outwardly-toothed sector gear element having, defined therein, a first outwardly-toothed sector gear portion and said first and second outwardly-toothed sector gear teeth in an integral manner;

said first outwardly-toothed sector gear element being rotatably provided on said shaft in such a manner that said first outwardly-toothed sector gear portion is disposed in a diametrically opposed relation with said first and second outwardly-toothed sector gear teeth with respect to said shaft; and

a second outwardly-toothed sector gear element including a second outwardly-toothed sector gear portion formed therein, said second outwardly-toothed sector gear element being fixedly provided on said shaft means associated with said operating lever,

 

wherein said second outwardly-toothed sector gear portion is in a meshed engagement with said first outwardly-toothed sector gear portion; and

 

a base support means on which said shaft and said shaft means are mounted, so that a whole of the ratchet-type lever mechanism and said sector gear means are provided as one unit;

 

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 staid 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.