Abstract: A seat mechanism for an item of seating furniture, in particular a chair, has a movable seat carrier and a backrest carrier, which are mounted on a main carrier. The backrest carrier can be pivoted about a horizontal pivot axis counter to the action of a force accumulator, and the seat carrier and the backrest carrier are coupled to each other. A lifting mechanism is provided. The lifting mechanism converts pivoting of the backrest carrier into a lifting movement of the seat carrier. A seat mechanism is provided with a weight-dependent resetting force for the backrest. The seat mechanism is distinguished by a simple construction in which the weight can be utilized efficiently. To increase the comfort, the seat is lowerable in the rear region and the resetting force is adjustable by means of a second force accumulator.

Abstract: A synchrotilt mechanism for a chair to provide improved control over the relative but synchronized tilting of the back and seat during tilting. The chair back is supported on a rigid upright assembly including lower lever arms which project under the chair seat and are coupled at forward ends to a horizontal tilt shaft which is disposed under the front of the chair seat and is supported on a control housing fixed to the upper end of the base pedestal. A tension control mechanism is coupled between the tilt shaft and the control housing for normally urging the upright arrangement, and the chair back, into an upright position. The chair seat is movably supported on the lower lever arms by a support arrangement which permits the chair seat to pivot relative to the upright assembly about a generally transverse horizontal axis which is preferably slightly below the upper surface of the seat when the latter is in a nondeformed condition, i.e., the seat is not occupied.

Abstract: A synchrotilt mechanism for a chair to provide improved control over the relative but synchronized tilting of the back and seat during tilting. The chair back is supported on a rigid upright assembly including lower lever arms which project under the chair seat and are coupled at forward ends to a horizontal tilt shaft which is disposed under the front of the chair seat and is supported on a control housing fixed to the upper end of the base pedestal. A tension control mechanism is coupled between the tilt shaft and the control housing for normally urging the upright arrangement, and the chair back, into an upright position. The chair seat is movably supported on the lower lever arms by a support arrangement which permits the chair seat to pivot relative to the upright assembly about a generally transverse horizontal axis which is preferably slightly below the upper surface of the seat when the latter is in a nondeformed condition, i.e., the seat is not occupied.