Patent attributes
A synchronous office chair comprising a support (1) firmly connected with a supporting column, a seat base (2) articulated on a tilting axis (4) support with a flange (5) and a backrest (3) with a back bracket (6). The back bracket (6) features a first, second and third cam tracks (7, 8, and 9) and engages in an interstice between support (1) and seat base (2). Said seat base (2) with flange (5) and backrest (3) with back bracket (6) are formed to execute a synchronous movement. A first roller bearing (10) is mounted on flange (5) of seat base (2) that engages in the first cam track (7) of back bracket (6) and in which the synchronous movement is guided in first cam track (7). A second roller bearing 11 is mounted on seat base (2) that engages in second cam track (8) of back bracket (6) and in which synchronous movement is guided in second cam track (8). A third roller bearing (12) is mounted on support (1) that engages in third cam track (9) of back bracket (6) and in which synchronous movement is guided in third cam track. A synchronous movement takes place such that the seat base (2) with flange (5) execute a first tilting movement about a tilting axis (4), whilst backrest (3) with back bracket (6) execute a second tilting movement about a virtual axis (13). Based on the magnitude it is about two to three times as large as the first tilting movement and a translational movement at the same time. Moreover, the momentary pivot of the second tilting movement about the virtual axis (13) essentially lies at the same distance above the rear middle part of seat base (2).
