Steelcase Inc.

Leon Goldick

Douglas C Ball

Alain Deslauriers

Jeff G Sokalski

A chair includes a base having a control assembly operably supporting a seat assembly and also a back assembly for movement about a seat tilt axis and a back tilt axis, respectively. The back assembly includes a flexible sheet supported at upper/outer corners by a back support structure and hanging downwardly. The flexible sheet includes a lower portion coupled to the back support structure by a tensioner for holding the lower portion rearwardly. A vertically-adjustable lumbar mechanism is adjustably supported on the back support structure and operably engages the flexible sheet for flexing a lumbar area of the flexible sheet forwardly to provide an optimal ergonomic horizontal and vertical convex shape for postural lumbar support.

Back construction for seating unit

Chair construction

A chair includes a base having a control assembly operably supporting a seat assembly and also a back assembly for movement about a seat tilt axis and a back tilt axis, respectively. The back assembly includes a flexible sheet supported at upper/outer corners by a back support structure and hanging downwardly. The flexible sheet includes a lower portion coupled to the back support structure by a tensioner for holding the lower portion rearwardly. A vertically-adjustable lumbar mechanism is adjustably supported on the back support structure and operably engages the flexible sheet for biasing an intermediate portion of the flexible sheet forwardly to both form the intermediate portion into a forwardly convex shape for postural lumbar support and also to tension the flexible sheet.

A chair includes a base having a control, and a seat and a back tilt bracket pivoted to the control for synchronous movement. An extension is adjustably supported on the back tilt bracket and is pivotally connected to a back support structure and a backrest frame in a four-bar linkage arrangement. The extension is adjustable to change the angular position of the back when in the rest position, and further provides a back tilt axis that is located rearward of a rear edge of the seat, which provides a unique back movement upon recline that is more rearward and less downward than most synchrotilt chairs. The back support structure includes a spine assembly pivoted to a rear end of the extension and extends upwardly. Armrests are operably supported on the spine assembly for vertical adjustment by an armrest mount, and a handle on the armrests is operably connected to a latch on the armrest mount for easy adjustment of the armrests. The arrangement of the backrest frame, the spine assembly, the back tilt bracket and the seat with side supports provides a unique synchronous movement that, among other things, pivots the armrests at an angular rate between a rate of the seat and the back during recline of the back. The back includes a flexible back shell having a lumbar section, a lumbar slide slidably engaging a rear surface of the back shell and operably supported thereagainst for changing a vertical shape of the lumbar section, and lumbar side arms engaging a rear surface of the back shell and also operably supported thereagainst for changing a horizontal shape of the lumbar section. A method related to the above is also contemplated.

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Beaconsville, Canada

Leon Goldick