Abstract: A back support includes a base, a seat, and a back frame pivoted to the base. The seating unit has a flexible back (i.e., back shell) supported on the back frame and having stiff upper and lower sections connected by a forwardly protruding flexible lumbar section for providing lumbar support to a seated user. A spring mechanism is connected to the back frame and to a center lower edge of the flexible back. The spring mechanism biases the flexible back to bias the lumbar toward a forwardly protruding shape to provide optimal lumbar support when in the upright position and also during recline of the seated user.

Abstract: A back support includes a base, a seat, and a back frame pivoted to the base. The seating unit has a flexible back (i.e., back shell) supported on the back frame and having stiff upper and lower sections connected by a forwardly protruding flexible lumbar section for providing lumbar support to a seated user. A spring mechanism is connected to the back frame and to a center lower edge of the flexible back. The spring mechanism biases the flexible back to bias the lumbar toward a forwardly protruding shape to provide optimal lumbar support when in the upright position and also during recline of the seated user.

Abstract: A back construction includes a base with a yoke formed by a cross member and upright side arms that define a U-shape, armrests supported by the side arms, and a seat and back also supported by the side arms for synchronized motion upon recline of the back. Specifically, the side arms define a back tilt axis about which the back rotates upon recline. The back includes a back structure with configured ends that engage the side arms for rotation about the back tilt axis, and further define a seat tilt axis for supporting rotation/movement of the seat upon recline of the back.

Abstract: A back construction includes a back shell having stiff thoracic and pelvic regions connected by a flexible lumbar region in a manner adapted to ergonomically support a seated user. The back shell includes spaced-apart resilient edge strips and leaf springs attached to or embedded into the edge strip. The springs match a curvature of the strips and span the lumbar region, biasing the lumbar region of the back shell forwardly in a manner distributing stress applied to the lumbar region by the seated user.

Abstract: A seating unit includes a seating unit having a base, a seat and a back operably pivoted to the base for synchronous movement including recline of the back and forward movement of the seat, an adjustable variable back stop adjustably engaging the seat for adjustably limiting a rearward tilt of the back, and a handle. The handle and the back stop are supported for independent movement, but are interconnected by a connecting mechanism including a pair of links so that the back stop is selectively adjusted upon rotation of the handle.

Abstract: A back construction includes an inverted U-shaped back frame and a back shell supported on the back frame and having stiff thoracic and pelvic regions connected by a flexible lumbar region in a manner adapted to ergonomically support a seated user. The lumber section includes a plurality of vertically spaced slots to increase its flexibility. The back shell has a complex curved shape that is forwardly concave in horizontal cross section and forwardly convex in vertical cross section. A force-generating mechanism biases the lumber section forwardly for lumbar support to a seated user.

Abstract: A back construction includes a back shell having stiff thoracic and pelvic regions connected by a flexible lumbar region in a manner adapted to ergonomically support a seated user. The back shell includes springs that press on a rear surface of the back shell to bias the flexible lumbar region forwardly so as to support a seated user, thus biasing the lumbar region of the back shell forwardly in a manner distributing stress applied to the lumbar region by the seated user.

Abstract: A seating unit is provided having a base, a back frame pivoted to the base for movement between upright and reclined positions, and a seat slidably supported on the base assembly and pivoted to the back frame so that the seat moves forwardly and its rear moves forwardly and downwardly with the back frame upon recline. A flexible back shell is connected to the back frame at top and bottom locations for controlled flexure when a seated user reclines and/or flexes his/her back, and is provided with lumbar adjustment for improved lumbar force/support and shape.

Abstract: An armrest structure includes a support and a body rotatably mounted on the support. The support includes a pair of protrusions and the body includes a notched channel for receiving the protrusions. By rotating the body on the support, the protrusions are repositioned in the notched channel between selected stable use positions. The notches are located on both sides of the channel such that the body can be located in a first position with the first surface on the body facing generally upwardly for use, and a second position with the second surface on the body facing generally upwardly for use. By varying the surfaces on the body, and also the engagement of the protrusion with the notched channel, various spacial positions and functional surfaces can be selectively positioned for use.

Abstract: A back construction for a seating unit includes a back frame, and a compliant back having a forwardly-protruding lumbar support section that is characteristically flexible and bendable, such that the compliant back can be flexed to a plurality of different convex shapes. Top and bottom connections pivotally connect the compliant back to the back frame. An adjustable force-generating mechanism is operably attached to at least one of the compliant back and the back frame. The force-generating mechanism is constructed to provide an adjustable biasing force that adjustably biases the lumbar support section forwardly for optimal lumbar support for a seated user's back, but the force-generating mechanism characteristically provides the biasing force without forcing a shape change in the compliant back. A vertically adjustable lumbar support is slidably attached to the back shell.

Abstract: A seating unit includes a flexible back including a concavely-shaped lumbar region, and a tensioned cover stretched over the concavely-shaped lumbar region. A lumbar device is fit between the front surface and the covering, with a tension of the covering biasing the lumbar device against the lumbar region and resulting in a frictional force retaining the lumbar device in a selected vertical position. In one form, the lumbar device is sufficiently stiff to maintain its vertical cross sectional shape and to change a shape of the lumbar region as the lumbar device is adjusted vertically, but is sufficiently flexible to conform to a horizontal shape of the lumbar region as a seated user moves and twists while seated in the seating unit.

Abstract: A back for a seating unit, such as a chair, includes a back frame and a compliant back that is flexibly bendable to define different curvilinear shapes for sympathetically and ergonomically supporting a seated user's back. The back includes a bracket with forwardly-extending flanges pivotally connecting the compliant back to the back frame at a bottom connection generally aligned with a seated user's hip joint. The back also includes a top connection pivotally connecting the back to the back frame above the first connection. An adjustable torsional force-generating mechanism is connected to the first connection that biases a lumbar portion of the compliant back forward with respect to the chair. The top and bottom connections, in combination with the adjustable force generating mechanism, constrain the compliant back to move over a range that provides excellent ergonomic lumbar support to a seated user.

Abstract: A back for a seating unit, such as a chair, includes a back frame and a compliant back that is flexibly bendable to define different curvilinear shapes for sympathetically and ergonomically supporting a seated user's back. The back includes a belt bracket with forwardly-extending flanges pivotally connecting the back to the back frame at a first connection generally aligned with a seated user's hip joint. The back includes a second connection pivotally connecting the back to the back frame at a second location spaced vertically above the first connection. An adjustable force generating mechanism is connected to the first connection that biases a lumbar portion of the back forward with respect to the chair. The first and second connections, in combination with the adjustable force generating mechanism, constrain the compliant back to move over a range that provides excellent ergonomic lumbar support to a seated user.

Abstract: A seating unit is provided having a base assembly, a back frame pivoted to the base assembly for movement between upright and reclined positions, and a seat slidably supported on the base assembly and pivoted to the back frame so that the seat moves forwardly and its rear moves forwardly and downwardly with the back frame upon recline. A flexible back is connected to the back frame at top and bottom locations and is provided with lumbar adjustment for improved lumbar force/support and shape. A seat is provided with seat depth adjustment and with active and passive thigh flex support. A novel energy mechanism is provided that includes a moment arm shift adjuster for adjusting the spring tension on the back frame. The moment arm shift adjuster is readily adjustable and includes an overtorque device to prevent damage to components of the energy mechanism.

Abstract: A back construction for a seating unit includes a back frame, and a compliant back having a forwardly-protruding lumbar support section that is characteristically flexible and bendable, such that the compliant back can be flexed to a plurality of different convex shapes. Top and bottom connections pivotally connect the compliant back to the back frame. An adjustable force-generating mechanism is operably attached to at least one of the compliant back and the back frame. The force-generating mechanism is constructed to provide an adjustable biasing force that adjustably biases the lumbar support section forwardly for optimal lumbar support for a seated user's back, but the force-generating mechanism characteristically provides the biasing force without forcing a shape change in the compliant back. A vertically adjustable lumbar support is slidably attached to the back shell.

Abstract: A back for a seating unit, such as a chair, includes a back frame and a compliant back that is flexibly bendable to define different curvilinear shapes for sympathetically and ergonomically supporting a seated user's back. The back includes a bracket with forwardly-extending flanges pivotally connecting the compliant back to the back frame at a bottom connection generally aligned with a seated user's hip joint. The back also includes a top connection pivotally connecting the back to the back frame above the first connection. An adjustable torsional force-generating mechanism is connected to the first connection that biases a lumbar portion of the compliant back forward with respect to the chair. The top and bottom connections, in combination with the adjustable force generating mechanism, constrain the compliant back to move over a range that provides excellent ergonomic lumbar support to a seated user.

Abstract: A chair is provided having a base assembly, a back assembly pivoted to the base assembly for movement between upright and reclined positions, and a seat slidably supported on the base assembly and pivoted to the back frame so that the seat moves forwardly and its rear moves forwardly and downwardly with the back frame upon recline. A flexible back is connected to the back frame at top and bottom locations and is provided with lumbar adjustment for improved lumbar force/support and shape. A seat is provided with seat depth adjustment and with active and passive thigh flex support. A novel energy mechanism is provided that includes a moment arm shift adjuster for adjusting the spring tension on the back frame. The moment arm shift adjuster is readily adjustable and includes an overtorque device to prevent damage to components of the energy mechanism.

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 chair including a seat support, a seat movably supported on the seat support for movement between a raised position permitting sliding depth adjustment of the seat and a lowered position preventing adjustment, and a detent device for securely holding the seat in the raised position while the seat is being slidable adjusted. A rack is formed integrally on or attached to the bottom of the seat shell. The detent device includes a seat support bracket attached to a top of a chair control, and a pair of moldings attached to opposite sides of the bracket. The moldings each include upwardly facing teeth for selectively engaging the racks to hold the seat in a selected, depth adjusted position. A resilient finger on each molding is adapted to engage a ridge on the seat shell for selectively holding the seat in either a raised position or in a lowered position.