Back support witch adjustable lumbar device

摘要

A chair (10) includes a lower back frame (14), a back construction (18), including a back support (24) attached to the lower back frame (14), a cushion assembly (26) attached to the back support (24), and a vertically adjustable lumbar assembly (28). The lumbar frame includes a transition shell (102) and a vertically sliding lumbar device (108) having a plurality of horizontal flexible wires (109). A lower edge (114) of the transition shell (102) is positioned on top of an uppermost horizontal flexible wire of the lumbar device (108). The lumbar device (108) is operably slidably mounted between the outer shell (24) and cushion assembly (26) and the transition shell upper edge slides (112) between the outer shell (24) and the upholstery cushion assembly (26). Another chair includes a Y-shaped lower back frame (14) having two uprights (32) and a cross-piece (34) attached to the back support. An overlap flange (44) and channel-shaped flange (32) mate to form an overlap joint, including a box beam (98) for added structural support.