Patent ID: 7722121

Claim:
A reclining device, comprising: a base plate; a ratchet plate superposed on the base plate such that the ratchet plate is rotatable relative to the base plate; an operation shaft rotatably disposed on a rotation center axis of the ratchet plate; a circular concavity formed on a surface of the ratchet plate opposed to the base plate around the operation shaft; inside teeth provided on an inner circumferential wall surface of the concavity; pawls disposed in the concavity and provided with outside teeth on front end surfaces of the pawls, the outside teeth engaging with and disengaging from the inside teeth in a radial direction of a teeth end circle of the inside teeth, the pawls having rear end surfaces; guide projections provided on the base plate for slidingly guiding the pawls in the radial direction; a cam disposed in a space on the side of rear end surfaces of the pawls and rotatable with the operation shaft to press the rear end surfaces of the pawls; urging means for urging the cam in the direction where the outside teeth of the pawls engage with the inside teeth of the ratchet plate; cam grooves formed on the pawls between the outside teeth on front end surfaces of the pawls and the rear end surfaces of the pawls pressed by the cams, the grooves being open at least to the ratchet plate; and a release plate disposed between the ratchet plate and the pawls and the cam such that the release plate is rotatable with the cam, wherein: projections engagable with the cam grooves of the pawls are integrally formed on a rotation end of the release plate; and when the operation shaft is rotated against an urging force produced by the urging means, the release plate forces the pawls to shift toward a rotation center of the cam by the interaction of the cam grooves of the pawls and the projections of the release plate such that the outside teeth of the pawls are separated from the inside teeth of the ratchet plate.