Patent ID: 6886888

Claim:
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.