Synchronizing mechanism for correlated seat/backrest motion of an office chair

A synchronizing mechanism for correlated seat/backrest motion of an office chair, comprising

• a base carrier (2) to be placed on a chair column (4);
• a seat carrier (6), which is pivotable about a transverse axis, and at its front end (21), articulated to the base carrier (2);
• a backrest carrier (7), which is also pivotable about a transverse axis and articulated to the base carrier (2) and which is coupled with the seat carrier such that a backward pivoting motion of a backrest induces a lowering motion of a rear end of the seat carrier (6);
• the backrest carrier (7) being pivotably mounted on the base carrier (2) by a cam arrangement (8, 10) that defines a four-bar chain;
• the cam arrangement (8, 10) being comprised of front and rear cams (8, 10) that are articulated to the base carrier (2) and of the backrest carrier (7) itself as a coupling of the four-bar chain;
• and
• the seat carrier (6), by its rear end (19), being articulated to the backrest carrier (7);
• wherein the joint between the base carrier (2) and the seat carrier (6) is a turning and sliding joint (22) so that a lowering motion of the seat carrier (6) is combined with a horizontal sliding motion rearwards.