An adjustable chair support system includes a first seat back support member spaced from a second seat back support member, and a seat back tensioning assembly that extends between the first and second seat back support members. The seat back tensioning assembly includes a carrier coupled to the first seat back support member, the carrier including an adjustable tension member and a first guide member, a pair of second guide members coupled to the second seat back support member, and a cable extending from the adjustable tension member into engagement with one of the pair of second guide members, with the first guide member, with the other of the pair of second guide members, and then returning to the adjustable tension member.

An office chair including a chair back assembly that is independently adjustable to adjust the vertical height of the chair back and to provide lumbar support. The chair back assembly includes a flexible back shell that is movable vertically along a back support yoke. The vertical movement of the flexible back shell adjusts the vertical height of the chair back assembly relative to the seat. The chair back assembly further includes a lumbar adjustment mechanism having an adjustment cable connected to a bottom end of the flexible back shell. Operation of the lumbar adjustment mechanism moves the bottom end of the flexible back shell vertically within a pair of spaced lower movement slots. The movement of the bottom end of the flexible back shell increases the amount that the flexible back shell protrudes from the back support yoke, thereby increasing the lumbar support.

A new easy-assemble seatback includes a seatback frame adapted to be connected to a seat. The seat back frame has a pair of opposite sides. The frame supports at least one flexible panel from a top panel connection so the panel hangs and rotates freely from the connection on the frame. The panel is formed from a flexible material which may include wood, metal, metal alloy or plastic. Panel-to-frame assembly is done by hand. The frame includes a stop member connected to the frame that impedes free rotation of the flexible panel. Since the panel covers most all of the load bearing seatback area, fewer heavyweight metal supportive elements are necessary. The new seatback is longer lasting, lighter in weight and deployable as a result.

A lumbar support assembly, a backrest assembly, and a method for manufacturing a lumbar support assembly are provided. The lumbar support assembly includes a plate member configured to flex and conform to a lumbar region of a user, the plate member includes a mesh structure including a plurality of interconnected elements. The interconnected elements define a plurality of Y-shaped voids therebetween, and each interconnected element includes an edge portion thinner than a center portion. The lumbar support assembly also includes a frame member supporting the plate member.