Abstract: A locking device having a tubular body, in which a stationary nut member is fixed and a lead screw is threadedly engaged with and through the stationary nut member. A lock nut member is threadedly engaged about the lead screw and biased by a biasing element to a frictional contact with the stationary nut member, so that a friction is caused between those two nut members, thereby preventing a relative threaded movement between the lead screw and the stationary nut member and thus normally setting this locking device in a locked state. The lock nut member may be rotated by an operation element about the lead screw against the biasing element so as to bring the lock nut member itself out of contact with the stationary nut member, thereby allowing the relative threaded movement between the lead screw and stationary lock member for an unlocking purpose.

Abstract: A seat suspension device for use in an automotive seat which comprises a pair of right and left X-shaped links for connecting a lower frame with an upper frame and a torsion bar journaled to the pivotally-connected portions of the two X-shaped links. The torsion bar includes two ends, with one end thereof being engaged with one of the X-shaped links and the other end engaged with the other X-shaped link, so that the upper frame can be supported resiliently relative to the lower frame.

Abstract: A weight adjustment support device for a vehicle seat such as an automotive seat is disclosed which is capable of adjusting the cushioning property of the seat according to weights or taste of an occupant. The device includes a mounting frame and a seat supporting frame on which the seat is placed. A pair of X-shaped expansion legs are provided between the two frames to be able to raise or fall the seat supporting frame vertically. A pair of wedge members are provided to secure one end of the expansion leg via elastic means. The two wedge members are combined such that the slanting surface of one wedge member having a grade is applied against the slanting surface of the other wedge member having the same but oppositely directed grade. The one wedge member is then moved by means of a feed mechanism to vary the distance between the respective bottom surfaces of the two wedge members so as to be able to adjust the energizing forces of the elastic means.