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 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 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 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: 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 seating unit includes a seat and back operably supported for synchronized reclining movement. The back includes a back support with separate upper and lower portions pivotally coupled to a back frame at upper and lower connections, respectively. The upper and lower portions combine to define a forwardly-protruding convex shape and include mating structure forming an expansion joint that permits collapse and expansion as the upper and lower portions are flexed between a more-convex shape and a more-planar shape. In one form, the lower portion includes first and second sections pivoted together, with the upper portion and the first and second sections forming thoracic, lumbar, and pelvic regions of the back support, respectively.

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: A seating unit includes a seat and back operably supported for synchronized reclining movement. The back includes a back support with separate upper and lower portions pivotally coupled to a back frame at upper and lower connections, respectively. The upper and lower portions combine to define a forwardly-protruding convex shape and include mating structure forming an expansion joint that permits collapse and expansion as the upper and lower portions are flexed between a more-convex shape and a more-planar shape. In one form, the lower portion includes first and second sections pivoted together, with the upper portion and the first and second sections forming thoracic, lumbar, and pelvic regions of the back support, respectively.

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 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. The seat includes a front section adjustably and/or flexibly supported on a rear section for optimal comfort while supporting a seated adult user's thighs, With the rear section being configured to carry a majority of the weight of a typical seated adult user. A novel energy mechanism is provided that includes a moment arm shift adjuster for adjusting the spring tension on the back frame.

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 seating unit is provided having a base assembly with a particularly shaped housing and rigid upright side arms, 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.