Abstract: The invention relates to a synchronizing mechanism for a chair comprising a base part which defines a rotational axis, a backrest support for supporting a backrest and a seat support for supporting a seat. The backrest support is pivotably supported on the base part about a first pivot, and the seat support is pivotably supported on the backrest support about a second pivot. The first pivot of the backrest support is fixed relative to the base part and the second pivot of the seat support is movable relative to the base part. In a basic position, the second pivot is in a lower basic position and the seat support rests against a support structure. In an upper end position, the movable second pivot is moved substantially vertically into an upper end position and the seat support is arranged at a distance to the support structure.

Abstract: A chair comprises a seat with a seat carrier comprising a buttock section at the rear and a knee section at the front, a height adjustment device coupled to the seat, and a foot part configured to be placed on a surface. The height adjustment device is configured to change the distance between the seat and the foot part. The seat is designed in such a manner that a height of the buttock section of the seat carrier and a height of the knee section of the seat carrier can be changed relative to one another. The chair further comprises a blocking structure configured to block the height adjustment device when the height of the buttock section of the seat carrier and the height of the knee section of the seat carrier are in a target position relative to one another.