Synchronizing mechanism

Abstract

A synchronizing mechanism provides a correlated seat-backrest movement of an office chair. To provide a self-adjusting synchronizing mechanism which is structurally simple, a backrest support is flexibly connected directly both to a base support so as to be pivotable about a transverse axis and to a seat support such that a pivoting movement of a backrest from an initial position into a rearwardly pivoted position induces an immediate lowering movement of the rear region of the seat support, when viewed in the longitudinal direction of the chair, rearwardly downward. The seat support is flexibly connected to the base support by a coupling element which is hinged to the seat support and to the base support such that when the backrest performs the pivoting movement from the initial position into the rearwardly pivoted position, an immediate lifting movement of the front region of the seat support, is effected rearwardly upward.

1 - 10 . (canceled) 
     
     
         11 . A synchronizing mechanism for a correlated seat-backrest movement of an office chair, the synchronizing mechanism comprising:
 a base support for placing on a chair column of the office chair;   a seat support having a front region and a rear region for supporting a seat of the office chair;   a backrest support for supporting a backrest of the office chair, said backrest support being flexibly connected directly both to said base support so as to be pivotable about a transverse axis and to said seat support such that a pivoting movement of the backrest from an initial position into a rearwardly pivoted position induces an immediate lowering movement of said rear region of said seat support, when viewed in a longitudinal direction of the office chair, rearwardly downward;   a front coupling element, said seat support being flexibly connected to said base support by said front coupling element, said front coupling element being hinged to said seat support and to said base support such that when the backrest performs the pivoting movement from the initial position into the rearwardly pivoted position, an immediate lifting movement of said front region of said seat support, when viewed in the longitudinal direction, is effected rearwardly upward; and   a spring mechanism for adjusting a pivoting resistance of the backrest, said spring mechanism containing at least one spring element connecting said base support to said backrest support.   
     
     
         12 . The synchronizing mechanism according to  claim 11 , further comprising a rear coupling element, which is connected rigidly to said backrest support or is realized as an integral component part of said backrest support, and is defined as a result of positions of first and second hinging points of said backrest support on said base support, said rear coupling element rigidly connected also to said seat support, at least one of a position or a length of said rear coupling element, with consideration to a position and/or a length of said front coupling element which is disposed between said seat support and said base support, influences the correlated seat-backrest movement to be achieved. 
     
     
         13 . The synchronizing mechanism according to  claim 12 , wherein the first hinging point of said rear coupling element on said seat support, when viewed in the longitudinal direction of the seat, lies behind the second hinging point of said rear coupling element on said base support in each position of said backrest support. 
     
     
         14 . The synchronizing mechanism according to  claim 12 , wherein a first hinging point of said front coupling element on said seat support, when viewed in the longitudinal direction of the seat, lies in front of a second hinging point of said front coupling element on said base support in each position of said backrest support. 
     
     
         15 . The synchronizing mechanism according to  claim 12 , further comprising a pure rotating joint, said front coupling element is connected to said seat support by means of said pure rotating joint. 
     
     
         16 . The synchronizing mechanism according to  claim 11 , wherein said spring element is connected to said base support as well as to said backrest support. 
     
     
         17 . The synchronizing mechanism according to  claim 16 , wherein said spring element is disposed in such a manner that an effective line of said spring element in a non-pivoted initial position is substantially perpendicular to a line which connects a hinging point of said backrest support on said base support to a point of application of said spring element on said backrest support. 
     
     
         18 . The synchronizing mechanism according to  claim 11 , wherein said spring mechanism contains adjusting means for adjusting a preload of said at least one spring element, wherein said adjusting means include an adjusting handle which can be pulled out of said base support from a rest position incorporated in said base support into an actuating position for adjusting the preload. 
     
     
         19 . The synchronizing mechanism according to  claim 18 , wherein said at least one spring element is a helical tension spring and said adjusting means include adjusting elements which are actuatable by means of said adjusting handle and by means of which a spacing between spring ends of said helical tension spring is modifiable. 
     
     
         20 . The synchronizing mechanism according to  claim 11 , wherein said spring element is connected to said a front region of said base support as well as to a hinging point of said backrest support on said seat support or in a direct vicinity of the hinging point.