Abstract: A vehicle front seat of the kind capable of being selectively rotated into a forward position or rearward position has a turntable unit or rotation adjusting mechanism provided between the seat and a vehicle floor. The rotation adjusting mechanism includes a stationary circular guide and a rotating disk disposed inside the stationary guide. The rotating disk is provided with a latching arm having an engagement tooth. The stationary guide has a locking through hole for engagement with the engagement tooth of the latching arm. A cam is disposed inside the locking through hole and capable of contacting the engagement tooth inserted into the locking through hole. The cam is rotatable in response to movement of the engagement tooth. An amount of rotation of the cam is detected by a microswitch. The cam is provided with first and second circular arc cam surfaces and capable of absorbing possible errors in attached positions of the constituent parts of the rotation adjusting mechanism.

Abstract: A rotating device of a seat has a lower base member secured to a vehicle floor. The lower base member includes a radially inside annular raised part and a radially outside depressed annular part. An annular holder member includes a radially inner part and a radially outer part. The radially inside part is concentrically put on and secured to the radially inside annular raised part in a manner to define therebetween an annular space. An upper base member mounts thereon the seat. The upper base member includes a radially inner annular depressed part and a radially outer annular raised part. The raidally inner annular depressed part is spacedly inserted into the annular space. A first group of rolling balls are operatively arranged between the radially outer depressed annular part and the radially inner annular depressed part. A second group of rolling balls are operatively arranged between the radially inner annular depressed part and the radially outer part.

Abstract: A rotatable seat mounted on a floor includes a seat proper, a lower base member mounted on the floor, an upper base member mounting thereon the seat proper and a retaining member for retaining the upper base member on the lower base member. The lower base member has a first annular portion. The upper base member has an annular flange portion and a second annular portion which is truncated conical in shape. The annular flange portion is rotatably put on the first annular portion such that the upper base member is rotatable relative to the lower base member. The retaining member is secured to the lower base member and has third and fourth annular portions. The third annular portion is opposed to and spaced from the first annular portion such that an annular groove for receiving therein the annular flange portion is defined therebetween.

Abstract: Herein disclosed is a powered rotating seat which comprises a seat proper; a lower base member adapted to be mounted on a floor, the lower base member including a structure by which an annular groove is defined; an upper base member mounting thereon the seat proper, the upper base member having a circular opening defined by an annular flange portion thereof, the upper base member being put on the lower base member having the annular flange portion slidably received in the annular groove; and an electric drive unit for rotating the upper base member relative to the lower base member upon energization thereof, the drive unit being installed in an inner space which is defined by the lower and upper base members.