Rotation mechanism for rotatable seat

Claim 1

A rotation mechanism for a rotatable seat in which said seat includes a seat cushion, an upper frame fixed to the seat cushion, and a lower frame fixed to a floor of a vehicle, said rotation mechanism comprising a slide frame slidably supported on said lower frame in a manner slidingly movable in a direction transversely of a longitudinal centerline of said vehicle, a rotation member rotatably provided on said slide frame, said rotation member being connected to said upper frame, a guide member provided on said lower frame, and a displacing means connected to an underside of said rotation member, said displacing means being movable along said guide member, wherein, said displacing means comprises four rollers so arranged that they are disposed equidistant at 90-degree angle from one another; wherein, said guide member is of a substantially isosceles triangle shape, and provided on a lateral section of said lower frame closest to said longitudinal centerline of said vehicle in such a manner that a vertex of said guide member extends inwardly of said lower frame in a direction transversely from said longitudinal centerline of said vehicle; and wherein one of said four rollers is in a rollable contact with said vertex of said guide member when said seat is set in a position which is parallel or orthogonal with respect to the longitudinal centerline of said vehicle, with said seat cushion being oriented in a seating direction which is parallel or orthogonal with respect to the longitudinal centerline of the vehicle.