Seat lifter with ratchet-type lever mechanism

A seat lifter for adjustment in height of a vehicle seat, comprising:

• a linkage means for operative connection with the vehicle seat, said linkage means including a first link means and a second link means, each link means adapted to be pivotally connected with forward and rearward sides of the vehicle seat, respectively, thereby allowing rotative vertical motion of the linkage means, wherein one of said first and second link means is formed with a bell crank portion in an integral manner;
• a drive means operatively connected with said linkage means;
• said linkage means including a rotation transmission link means operatively connected between said linkage and drive means such that an operative rotation force applied from the drive means is transformed into said rotative vertical motion of the linkage means;
• a brake means for providing a braking action to the rotative vertical motion of said linage means;
• said rotation transmission link means including a sector gear means which is in a meshed engagement with said brake means;
• and
• said drive means comprising a ratchet-type lever mechanism which includes:
• a support base means;
• a ratchet gear wheel means having:
• a central axis portion rotatably supported by said support base means and securely connected with said brake means;
• and an outer gear teeth defined circumferentially thereof;
• a ratchet base means attached rotatably around the central axis portion of said ratchet gear wheel means;
• a lever means attached rotatably around the central axis portion of said ratchet gear wheel means;
• a bifurcated pawl means pivotally attached on said ratchet base means, said bifurcated ratchet pawl means having first and second pawl portions extending from one side thereof, wherein said bifurcated ratchet pawl means is operatively connected with said lever means at another side thereof opposite to said one side, with such an arrangement that the bifurcated ratchet pawl means is selectively rotatable from a neutral position where the bifurcated ratchet pawl means is normally out of engagement with said ratchet gear wheel means, so as to bring a selected one of said first and second pawl portions to engagement with said outer gear teeth of the ratchet gear wheel means;
• a first biasing means for normally biasing said ratchet base means in a direction to said neutral position;
• and
• a second biasing means for normally biasing said lever means to a neutral non-use position.