Abstract: A structural support shell for a tilt-back chair has a back portion, a seat portion, and a flexible compression zone extending between the back and seat portions in an integrally molded, one-piece unit. The chair has a base with a recline control pivoting recline control lever. The seat portion of the shell is fixed to the base and the back portion of the shell is fixed to the recline control lever. The flexible compression zone provides a simplified construction for an ergonomic chair design having an effective axis of rotation between the back portion and 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. The chair includes side arms that laterally and then rotatably engage side arm supporting connectors on the chair to facilitate assembly. The chair further includes a one-piece shell having tabs for mateably engaging flanges on the chair seat and back to also facilitate assembly.

Abstract: A vertically adjustable back construction is provided for chairs and the like of the type having a one-piece sculptured appearance. The back construction includes a lower back member with an upholstered upright portion, and an upper back member slidably mounted on the lower back member for movement between various back heights. The upper back member includes an upholstered, downwardly opening shroud portion, which is disposed over and covers at least the uppermost end of the upright portion on the lower back member, and translates thereover to permit ready vertical adjustment of the upper back member by the user to accommodate different tasks and users, while preserving the one-piece sculptured appearance of the chair.

Abstract: A structural support shell for a tilt-back chair has a back portion, a seat portion, and a flexible compression zone extending between the back and seat portions in an integrally molded, one-piece unit. The chair has a base with a recline control pivoting recline control lever. The seat portion of the shell is fixed to the base and the back portion of the shell is fixed to the recline control lever. The flexible compression zone provides a simplified construction for an ergonomic chair design having an effective axis of rotation between the back portion and 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 tubular arm support, an armrest, a lateral adjustment mechanism and a vertical height adjustment mechanism. The lateral adjustment mechanism includes a plurality of nested slides. One slide is connected to the vertical height adjustment mechanism. An uppermost slide supports the arm rest. The slides are adjustable laterally with respect to each other to position the armrest with respect to the chair. The vertical height adjustment mechanism includes a tubular liner insertable into the arm support. The liner defines a bore and a plurality of vertically spaced notches or grooves. A latch tube telescopes within the bore of the liner. An upper end of the latch tube is connected to the lateral adjustment mechanism. The latch is pivotally positioned within the latch tube. The latch includes a latch end movable into and out of engagement with the notches. An actuator engages the latch to move it between locked and unlocked positions.

Abstract: A structural support shell for a tilt-back chair has a back portion, a seat portion, and a flexible compression zone extending between the back and seat portions in an integrally molded, one-piece unit. The chair has a base with a recline control and pivoting recline control lever. The seat portion of the shell is fixed to the base and the back portion of the shell is fixed to the recline control lever. The flexible compression zone provides a simplified construction for an ergonomic chair design having an effective axis of rotation between the back portion and 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 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: An adjustor for chairs with tilting backs and the like, comprises a threaded spindle connected with the chair back, and a gear wheel threadedly mounted on the spindle. The gear wheel is retained in a housing attached to a relatively stationary portion of the chair, such that when the chair back is tilted, the spindle rotates the gear wheel in the housing. A pawl is shifted into and out of engagement with the gear wheel to selectively lock the chair back in a wide variety of different angular positions.