Abstract: A crossmember is disclosed that includes an elongate rod portion and two latching claws. The rod portion has a central longitudinal axis, a first longitudinal end and a second longitudinal end substantially opposite the first longitudinal end. The first latching claw is arranged at the first longitudinal end of the rod portion and the second latching claw is arranged at the second longitudinal end of the rod portion. The first latching claw and the second latching claw each include a gripping portion shaped to correspond to a rod-shaped element and are designed to be mounted on the rod-shaped element without tools. The gripping portion of the first latching claw is offset from the gripping portion of the second latching claw with respect to the central longitudinal axis of the rod portion.

Abstract: A synchronous chair mechanism is disclosed for simultaneously changing a seat and a backrest of a chair from a zero position in which the backrest is tilted to a minimum extent relative to the seat, into an end position in which the backrest is tilted to a maximum extent relative to the seat. The synchronous chair mechanism includes a base that is connectable to a substructure provided for setting up the chair. The synchronous chair mechanism also includes a backrest carrier on which the backrest is mountable, a seat support that is designed for holding a seat, and a spring element having a front end and a rear end.