Chair including novel back construction

A chair comprising:

• a base assembly;
• a back frame pivoted to the base assembly for movement between upright and reclined working positions;
• and
• a compliant back operably attached to the back frame at a top connection and operably attached to the back frame at bottom connections, the compliant back including a forwardly-extending flange generally located along its lower edge forming an axis of rotation at the bottom connections, the axis being located proximate a rear section of the seat and in front of the compliant back, the compliant back including a thoracic portion, a pelvic portion, and a flexible lumbar portion constructed so that when a seated user flexes their lower back rearwardly, a pelvic portion of the compliant back moves pivotally downwardly and rearwardly about the axis, the lumbar portion of the compliant back flexibly moves generally rearwardly to form a more planar arrangement with the pelvic portion, and a thoracic portion of the back pivots about the top connection, whereby the compliant back, in combination with the back frame and base assembly, is adapted to provide postural support for a seated user's back that very comfortable and yet posturally supports significant flexing and moving of the seated user's torso and spine.

A chair construction comprising:

• a base assembly;
• a seat;
• a back frame pivoted to the base assembly for movement between upright and reclined positions;
• and
• a compliant back pivoted to the back frame at a fixed top connection and including forwardly-extending flanges pivoted to one of the back frame, the seat, and the base assembly at bottom connections, the bottom connections being spaced forwardly from a lower front central surface of the compliant back, whereby, upon flexure of a seated adult user's spine and lower back, the compliant back is adapted to flex sympathetically and follow flexure of the seated adult user's back and spine.

A chair comprising:

• a base assembly;
• a seat;
• an inverted U-shaped back frame having an intermediate top section and a pair of configured end sections pivoted to the base assembly, a T-shaped top connector protruding from the top section and a pair of bottom connectors in the configured end sections;
• a compliant back including a top recess configured to receive and frictionally engage the top connector, and further including a belt bracket along a lower edge with opposing flanges that extend forwardly a distance for connection to the bottom connectors;
• and
• a connecting mechanism pivotally connecting the opposing flanges to the bottom connectors at a location proximate a rear of the seat.

A back construction for a chair comprising:

• a back frame;
• a highly compliant back having a forwardly-protruding lumbar support section that is characteristically very flexible and bendable, such that the compliant back can be flexed to a plurality of different convex shapes;
• top and bottom connections pivotally connecting the compliant back to the back frame;
• and
• an adjustable force-generating mechanism operably attached to at least one of the compliant back and the back frame, the force-generating mechanism being constructed to provide an adjustable biasing force that adjustably biases the lumbar support section forwardly for optimal lumbar support for a seated adult user's back, but the force-generating mechanism characteristically providing the biasing force without forcing a shape change in the compliant back.

A back construction for a chair comprising:

• a back frame;
• a highly compliant back having a forwardly-protruding lumbar support section that is flexibly movable to a plurality of different convex shapes, with each shape being adapted to provide postural and comfortable support to a back of a seated adult user;
• top and bottom connections pivotally connecting the compliant back to the back frame;
• and
• an adjustable torsional force-generating mechanism operably attached to one or both of the compliant back and the back frame to bias the lumbar section forwardly for optimal lumbar support for the seated user's back, the torsional force-generating mechanism being operably mounted at the bottom connection to the back frame and the compliant back.

A chair comprising:

• a base assembly including a control housing having an energy source therein;
• a seat on the base assembly;
• a back support operably interconnected to the energy source for movement between an upright position and a reclined position, said back support including a back frame and a back shell, said back shell comprising a resiliently flexible polymeric sheet shaped to and adapted to support a back of a seated adult user, with a semi-rigid lower area disposed generally in a pelvic area on the chair, a flexible central area disposed above said lower area and generally in a lumbar area on the chair, and a semi-rigid upper area disposed above said central area in a thoracic area on the chair;
• said back frame having a first attachment coupling said upper area of said back shell to the back frame, and a plurality of pivotal second attachments for pivotally coupling said lower area of the said back shell to the back frame, the second attachments constraining movement of the lower area to force flexure to occur in a controlled sympathetic manner in the lumbar area in order to adapt the back support to assure continuous and comfortable support of the seated adult user's spine in the lumbar area during flexure of the seated adult user's spine while seated, said central area of said back shell comprising a plurality of vertically spaced apart slots in said sheet extending generally horizontally across a portion of the central area of said back support, said slots terminating prior to the perimeter edge of said sheet, whereby the said slots define a plurality of elongated horizontal resilient straps in said central area, each of said straps being dimensioned and adapted to provide resilient support for the seated adult user when sitting on the chair;
• and
• the lower area of the back shell including a reinforcement having forward extending flanges pivotally coupled to the second attachments of the back frame, said reinforcement and pivotal attachment being adapted to provide movable firm support for at least a portion of the pelvic area of the seated user.

A chair comprising:

• a base assembly including a control housing having an energy source therein;
• a seat on the base assembly;
• a back support operably interconnected to the energy source for movement between an upright position and a reclined position, said back support including a back frame and a back shell, said back shell comprising a resiliently flexible polymeric sheet shaped to and adapted to support a back of a seated adult user, with a semi-rigid lower area disposed generally in a pelvic area on the chair, a flexible central area disposed above said lower area and generally in a lumbar area on the chair, and a semi-rigid upper area disposed above said central area in a thoracic area on the chair;
• said back frame having a first attachment coupling said upper area of said back shell to the back frame, and a plurality of pivotal second attachments for pivotally coupling said lower area of the said back shell to the back frame, the second attachments constraining movement of the lower area to force flexure to occur in a controlled sympathetic manner in the lumbar area in order to adapt the back support to assure continuous and comfortable support of the seated adult user's spine in the lumbar area during flexure of the seated adult user's spine while seated, said central area of said back shell comprising a plurality of vertically spaced apart slots in said sheet extending generally horizontally across a portion of the central area of said back support, said slots terminating prior to the perimeter edge of said sheet, whereby the said slots define a plurality of elongated horizontal resilient straps in said central area, each of said straps being adapted and dimensioned so as to provide resilient support for the seated adult user when sitting on the chair;
• and
• the lower area of the back shell including a reinforcement having forward extending flanges pivotally coupled to the second attachments of the back frame, said reinforcement and pivotal attachment being adapted to provide movable firm support for at least a portion of the pelvic area of the seated user, the pivotal second attachments for pivotally coupling said lower area of the said back shell to the back frame including a biasing device that biases the central area of the back shell in a forward direction.

A chair comprising:

• a base assembly including a control housing having an energy source therein;
• a seat on the base assembly;
• a back support operably interconnected to the energy source for movement between an upright position and a reclined position, said back support including a back frame and a back shell, said back shell comprising a resiliently flexible polymeric sheet shaped to and adapted to support a back of a seated adult user, with a semi-rigid lower area disposed generally in a pelvic area on the chair, a flexible central area disposed above said lower area and generally in a lumbar area on the chair, and a semi-rigid upper area disposed above said central area and in a thoracic area on the chair;
• and
• said back frame having a first attachment coupling said upper area of said back shell to the back frame, and a plurality of pivotal second attachments for pivotally coupling said lower area of the said back shell to the back frame, the second attachments constraining movement of the lower area to force flexure to occur in a controlled sympathetic manner in the lumbar area in order to adapt the back support to assure continuous and comfortable support of the seated adult user's spine in the lumbar area during flexure of the seated adult user's spine while seated, the lower area of the back shell including forward extending flanges forming an axis of rotation at the pivotal second attachments of the back frame, said axis of rotation being located at or rearward of a rear of the seat so that the axis is generally adapted for location proximate a seated adult user's pelvic bone so that when the seated adult user flexes their lower back rearwardly, the lower portion of the back shell moves downwardly and rearwardly, and the central portion of the back shell flexes generally rearwardly to form a more planar arrangement with the lower portion.

A chair comprising:

• a base assembly including a control housing having an energy source therein;
• a seat on the base assembly;
• a back support operably interconnected to the energy source for movement between an upright position and a reclined position, said back support including a back frame and a back shell, said back shell comprising a resiliently flexible polymeric sheet shaped to and adapted to support a back of a seated adult user, with a semi-rigid lower area disposed generally in a pelvic area on the chair, a flexible central area disposed above said lower area and generally in a lumbar area on the chair, and a semi-rigid upper area disposed above said central area and generally in a thoracic area on the chair;
• and
• said back frame having a first attachment coupling said upper area of said back shell to the back frame, and a plurality of pivotal second attachments for pivotally coupling said lower area of the said back shell to the back frame, the second attachments constraining movement of the lower area to force flexure to occur in a controlled sympathetic manner in the lumbar area in order to adapt the back support to assure continuous and comfortable support of the seated adult user's spine in the lumbar area during flexure of the seated adult user's spine while seated, said back frame defining a curvilinear arch.

A chair comprising:

• a base assembly including a control housing having an energy source therein;
• and
• a back assembly movably supported on the back assembly and including a back support operably interconnected to the energy source, said back support including a back frame and a back shell connected to the back frame by at least one connection, said back shell comprising a resiliently flexible polymeric sheet adapted to support a back of a seated adult user, the sheet including a lower area disposed generally in a pelvic area on the chair, a central area disposed above said lower area and generally in a lumbar area on the chair, and an upper area disposed above said central area and generally in a thoracic area on the chair;
• a cushion on a forward face of the back shell;
• and a vertically adjustable lumbar support located in front of the back shell, the lumbar support being movably supported on the back support and configured for vertical adjustment to change a shape of a front surface of the back in the lumbar area, said vertically adjustable lumbar support including laterally extending handles constructed to engage and follow configured non-parallel opposing perimeter edges of the back shell and constructed to slidably engage the vertically adjustable lumbar support to permit the handles to adjust laterally in and out to follow the perimeter edges.

A chair comprising:

• a base assembly;
• a seat supported on the base assembly;
• a back frame pivoted to the base assembly for movement between upright and reclined working positions;
• a compliant back pivotally connected to the back frame in at least one top connection and pivotally connected to one of the back frame and the seat at bottom connections vertically spaced from the at least one top connection, the bottom connections being located proximate a rear of the seat and in front of a bottom of the compliant back so that the bottom connections define an axis at a rear of the seat that is adapted to be generally aligned with a seated adult user's hip bone, the compliant back having a stiff thoracic section and a stiff pelvic section, the lumbar section being characteristically very flexible in a horizontal direction, such that the compliant back can be easily flexed to provide different shapes for optimal lumbar support, but the lumbar section being substantially incompressible in directions toward the thoracic and pelvic sections so that the lumbar section causes the thoracic and pelvic sections to pivot along predetermined paths about the top and bottom connections when the lumbar section is flexed, such that the compliant back undergoes controlled flexure between the top and bottom connections upon flexure of the lumbar section caused by flexure of a seated user's back;
• and
• the seat being operably supported on the base assembly to move in a synchronized angular motion with the back frame during recline of the back frame.

A chair comprising:

• a base assembly;
• a back frame pivoted to the base assembly for movement between upright and reclined working positions;
• and
• a compliant back operably attached to the back frame at a top connection and operably attached to the back frame at bottom connections, the compliant back including a stiff thoracic portion and a stiff pelvic portion connected by a flexible lumbar portion, the bottom connections being forward of the pelvic portion and above the seat, the top and bottom connections and thoracic, pelvic, and lumbar portions being constructed so that when a seated user flexes their lower back rearwardly, the pelvic portion of the compliant back moves pivotally downwardly and rearwardly, the lumbar portion of the compliant back flexibly moves generally rearwardly to form a more planar arrangement with the pelvic portion, and the thoracic portion of the back pivots about the top connection, whereby the compliant back, in combination with the back frame and base assembly, is adapted to provide postural support for a seated user's back that is very comfortable and yet posturally supports significant flexing and moving of the seated user's torso and spine.

A chair comprising:

• a base assembly;
• a seat operably supported on the base assembly;
• a back frame pivoted to the base assembly for movement between upright and reclined working positions;
• and
• a compliant back operably attached to the back frame at a top connection and operably attached to one of the seat and the back frame at bottom connections, the compliant back including a stiff thoracic portion and a stiff pelvic portion connected by a flexible lumbar portion, the bottom connections being forward of the pelvic portion and above the seat, the top and bottom connections and thoracic, pelvic, and lumbar portions being constructed so that when a seated user flexes their lower back rearwardly, the pelvic portion of the compliant back moves pivotally downwardly and rearwardly, the lumbar portion of the compliant back flexibly moves generally rearwardly to form a more planar arrangement with the pelvic portion, and the thoracic portion of the back pivots about the top connection, whereby the compliant back, in combination with the back frame and base assembly, is adapted to provide postural support for a seated user's back that is very comfortable and yet posturally supports significant flexing and moving of the seated user's torso and spine.