Patent ID: 8851570

Claim:
A seat lifter comprising: a first link rotatably coupled to each of a first base member and a first seat frame which are disposed on one of right and left sides of a seat; a second link rotatably coupled to each of a second base member and a second seat frame which are disposed on the other side of the seat, and interlockably coupled to the first link through a coupling member; and a lifting and lowering mechanism for lifting and lowering the first and second seat frames with respect to the first and second base members, the lifting and lowering mechanism including: a first lifting and lowering mechanism section having a first sun gear and a first planetary gear group to lift and lower the first seat frame with respect to the first base member; and a second lifting and lowering mechanism section having a second sun gear and a second planetary gear group to lift and lower the second seat frame with respect to the second base member in interlocking relation with the first lifting and lowering mechanism section, wherein the first planetary gear group has a plurality of first planetary gears each meshed with the first sun gear, the first seat frame includes a first-link coupling section having a first-frame internal gear, the first link includes a first link body with first and second ends, the first end of the first link body being coupled rotatably to the first base member, the second end of the first link body having a first-link internal gear maintained in meshed relation with the first planetary gear group, the first-link internal gear having fewer teeth than the first-frame internal gear, a planetary-gear operating section adapted to manipulatively allow the first planetary gear group to be moved circularly around the first sun gear, the planetary-gear operating section including a clutch plate, a cam and an operating lever, the cam being locked with the operating lever and being changeably locked and unlocked with respect to the clutch plate, the clutch plate having a shaft insertion hole rotatably receiving a shaft portion of the first planetary gears, and the first link body is rotatable with respect to the first-link coupling section during the circular movement of the first planetary gear group around the first sun gear and along the first-frame internal gear while being meshed with the first-frame internal gear and meshed with the first-link internal gear according to manipulation of the operating lever of the planetary-gear operating section, rotational manipulation of the operating lever causing rotation of the cam that is locked with the operating lever and causing rotation of the clutch plate when the clutch plate is locked with the cam, and the first link body is swingably movable about a rotation axis at the first end of the first link body.