Abstract: A chair includes a base, a seat, a back pivoted to the base and an inner shell construction connecting a cushion assembly to the back. A chair control includes a control housing, a pair of coil springs and an adjustment subassembly. The coil springs include ends which engage the back and bias the back to an upright position. The adjustment subassembly includes an adjuster plate pivoted to the control housing and engaging the other ends of the springs, an adjuster nut engaging the plate and an adjustment screw.

Abstract: A chair includes a base, a seat, a back pivoted to the base and an inner shell construction connecting a cushion assembly to the back. The shell includes a semi-rigid, flexible sheet having a back portion shaped to support a back area of an adult user. The back portion includes a central area and an upper area. A plurality of ribs are formed integrally with the sheet to stiffen the central area of the back portion for lumbar support yet permit the upper portion of the back portion to flex for improved freedom of movement of the upper back area of the user.

Abstract: A chair, with independent control of a lumbar portion of a seat back and a thoracic portion of the seat back, has a seat connected with a base and a control connected with the base, generally under the seat. A first support, pivotally connected with the control, extends from the control to the thoracic portion of the seat back. A second support extends to the lumbar portion of the seat back. The two supports operate independently and the thoracic and lumbar portions of the seat back rotate independently rearward with respect to the seat, providing sympathetic back support for a user. The thoracic portion may rotate laterally to follow twisting movements of a user's thoracic region. The lumbar portion may be connected with the second support to limit lateral rotation of the lumbar portion.

Abstract: A structural support shell for a tilt back chair has a back portion, a seat portion, and a compressible flex area extending between the back and seat portions in an integrally molded, one piece unit. The chain has a base with a recline control and pivoting back support lever. The seat portion of the shell is connected to the base and the back portion of the shell is connected to the back support lever. The compressible flex area provides for an ergonomic chair design having an effective axis of rotation between the back portion and the seat portion, which is located above the seat portion, forward of the back portion and generally adjacent to the hip joints of a seated user.

Abstract: A chair includes a base, a seat, a back pivoted to the base and an inner shell construction connecting a cushion assembly to the back. The shell includes a semi-rigid, flexible sheet having a back portion shaped to support a back area of an adult user. The back portion includes a central area and an upper area. A plurality of ribs are formed integrally with the sheet to stiffen the central area of the back portion for lumbar support yet permit the upper portion of the back portion of flex for improved freedom of movement of the upper back area of the user.

Abstract: A controlled deflection front lip arrangement is provided for seating, such as chairs and the like of the type having a base, and a seat with a rearward portion positioned to contact a buttock area of an adult user, and a forward portion positioned to contact a thigh area of the user. The rearward portion of the seat is attached to the base for support thereon. A spring connects the forward portion of the seat with the base in a manner such that body movement of a seated user deflects the forward portion of the seat upwardly and downwardly independently of the rearward portion of the seat to alleviate undesirable pressure at the thigh area of the user.

Abstract: A slip connector is provided for swivel chairs, and other similar seating, of the type having a base, a seat rotatably supported thereon, and a weight actuated height adjustor, which engages when the seat is unoccupied to facilitate adjusting the seat height, and disengages when the seat is occupied to permit the seat to swivel on the base without affecting the seat height. The slip connector includes two coupling members, which rotate about a common axis when the seat swivels about the base. A stop mechanism positively interconnects the coupling members causing them to rotate together when they assume a first, angular relationship.

Abstract: An integrated chair and control arrangement is provided for tilt back chairs, and other similar seating. The chair has a base, as well as a back and a bottom or seat which are interconnected for mutual rotation about a common axis. The common axis is located above the chair bottom, forward of the chair back, and generally adjacent to the hip joints of a seated user. A control supports the chair back and chair bottom on the base in a manner such that rearward tilting of the chair back simultaneously shifts the chair back, the chair bottom, and the location of the common axis in a manner which maintains the adjacent spatial relationship between the common axis and the hip joints of the seated user to provide improved comfort and support.

Abstract: A shell construction is provided for seating, such as chairs and the like, and comprises a semi-rigid, resiliently flexible sheet, having a generally L-shaped side elevational configuration. The sheet has a bottom shaped to support a buttock area of an adult user, and a back with a central area disposed directly behind a lumbar area of a seated adult user to support the same. An upper area of the back is disposed generally behind an upper back area of a seated user to selectively support the same. At least one rib is formed integrally on the rearward side of the sheet, and extends generally vertically along the central area of the back to stiffen the central area of the back in a vertical plane for firm support of at least the lumbar area of the seated user, yet permit at least the upper portion of the back to flex in a horizontal plane for improved freedom of movement of the upper back area of the seated user.

Abstract: A varible back stop is provided for tilt back charis, and other similar seating, such as the type having a stationary support, and a back which tilts with respect to the support. The variable back stop comprises a stop surface, and at least one stop member, which are located on associated portions of the chair support and the chair back. The stop surface and the stop member are mutually positioned such that rearward tilting of the chair back generally converges the stop surface and the stop member along a line of motion, and forward tilting of the chair back generally diverges the same. The stop member has an engaged position wherein at least a portion of the stop member is positioned in the line of motion to abut the stop surface upon rearward tilting of the chair back, and a disengaged position, wherein the stop member is positioned outside of the path of motion to avoid abutting the stop surface upon rearward tilting of the chair back.

Abstract: A slip connector is provided for swivel chairs, and other similar seating, of the type having a base, a seat rotatably supported thereon, and a weight actuated height adjustor, which engages when the seat is unoccupied to facilitate adjusting the seat height, and disengages when the seat is occupied to permit the seat to swivel on the base without affecting the seat height. The slip connector includes two coupling members, which rotate about a common axis when the seat swivels about the base. A stop mechanism positively interconnects the coupling members causing them to rotate together when they assume a first, angular relationship.