To provide a seat reclining apparatus having the remarkably enhanced rotational strength.
The apparatus includes: a fixing member 2 connected to the seat cushion; a pivot member 3 which is connected with a seat back and can freely rotates for the fixing member 2; an internal tooth 3a formed in the internal perimeter surface of the pivot member 3; a lock tooth 4 having an external tooth 4a which engages with the internal tooth 3a; a guide means 5 to guide the lock tooth 4 along the orbit; a cam 6 which pushes the lock tooth 4 to engage the external tooth 4a with internal tooth 3a and locks rotating of pivot member 3 for the fixing member 2; a spiral spring 7 which rotationally energizes the cam 6 in the lock direction; and an operating lever for rotating the cam 6 against energizing force of the spiral spring 7 in the unlock direction. A pair of guide protrusions 4b protruding to the fixing member 2 in the axial direction are formed in both sides of the lock tooth 4 as a guide means 5, and guide grooves 2a where the guide protrusions 4b go into to guide the lock tooth 4 are formed respectively in the inside surface of the fixing member 2.
Hiromichi Kobayashi
Tomioka Kiyoshi