Patent attributes
A locking mechanism for a rotation seat includes a plate member fixed to an underside of the rotation seat, a stopper member attached to the plate member, a base member fixed to a base, a rotary shaft which supports the plate member rotatably with respect to the base member, a locking recess formed in an intermediate portion of the guide slot, and a resilient member provided in the plate member for urging the stopper member in a direction in which the stopper member is locked to the locking recess. The base member is formed with a guide slot. The locking recess is formed continuously from the guide slot so that the width thereof becomes narrower with distance from the guide slot. When the stopper member moves in a guide direction along the guide slot and gets into the locking recess, the stopper member is urged in the direction.