Abstract: A back for a chair includes fabric panel with a flexible carrier attached to the panel around its periphery. The carrier is configured to be secured along a bottom edge to a bottom portion of a chair back frame member. The carrier is also secured to two vertical frame supports at its two upper corners. Preferably, the upper carrier and frame connections are ball and socket joints. A lumbar support is provided that is easily height adjustable, by providing tension to the back frame and requires no screws or adjustment knobs in its adjustment mechanism.

Abstract: A back for a chair includes fabric panel with a flexible carrier attached to the panel around its periphery. The carrier is configured to be secured along a bottom edge to a bottom portion of a chair back frame member. The carrier is also secured to two vertical frame supports at its two upper corners. Preferably, the upper carrier and frame connections are ball and socket joints. A lumbar support is provided that is easily height adjustable, by providing tension to the back frame and requires no screws or adjustment knobs in its adjustment mechanism.

Abstract: A back for a chair includes fabric panel with a flexible carrier attached to the panel around its periphery. The carrier is configured to be secured along a bottom edge to a bottom portion of a chair back frame member. The carrier is also secured to two vertical frame supports at its two upper corners. Preferably, the upper carrier and frame connections are ball and socket joints. A lumbar support is provided that is easily height adjustable, by providing tension to the back frame and requires no screws or adjustment knobs in its adjustment mechanism.

Abstract: A chair back is disclosed and includes a mesh material connected to a two-piece carrier, the carrier being deformable and stretchable. The carrier has a bottom edge including a groove and is engageable by tabs attached to a transverse member of a chair frame assembly. The upper ends of the carrier each includes an opening for receiving a spherical end portion of the upper end of the chair frame assembly. Engagement of the carrier with the chair frame assembly is accomplished by stretching the carrier and mesh between the transverse member and the spherical end portions. The chair back includes a lumbar support which is mounted to slide along the side edges of the carrier and along vertical supports of the chair frame assembly, the lumbar support causing the chair to tension forwardly. The chair back is pivotal under the influence of a chair user and is pivotally connected to the chair seat so as to cause the chair seat to also pivot in response.

Abstract: An ergonomic chair includes a four-bar linkage arrangement wherein a lower frame member is provided with a rigid front support and a rigid rear support with a seat member pivotably connected to the front support. A back rest has an upper support pivotably connected at an upper end of the rear support of the lower frame member. A link member pivotably connects at a first end to a rear support of the seat member and at second end to a lower support of the back rest. This novel arrangement permits tilting movement of the backrest rearwardly relative to the lower frame member causing elevation of a rear portion of the seat member, permitting the feet to remain on the floor and alleviating pressure on the user's thighs, while rotation occurs closely coincident with the pivot axis of the user's hips and while maintaining a generally uniform gaze line.

Abstract: A chair seat that is movable between an upright and a forward position includes a spring mechanism that biases the seat toward the upright position. The spring mechanism includes camming structures that utilize both compressional and torsional forces from the spring to bias the seat toward the upright position. The compression of the spring exerts a positive force that must be overcome before the seat can be moved out of its upright position. The chair seat is constructed from a number of discrete components that are secured together without the use of welding or separate fasteners, such as via snap-fits. The discrete components include positioning tabs, special shapes, and other features that prevent them from being improperly assembled. The components of the chair seat may all be constructed out of suitable durable plastics, such as polypropylene, polyethylene, polycarbonate, and glass filled thermoplastics.

Abstract: A chair seat that is movable between an upright and a forward position includes a spring mechanism that biases the seat toward the upright position. The spring mechanism includes camming structures that utilize both compressional and torsional forces from the spring to bias the seat toward the upright position. The compression of the spring exerts a positive force that must be overcome before the seat can be moved out of its upright position. The chair seat is constructed from a number of discrete components that are secured together without the use of welding or separate fasteners, such as via snap-fits. The discrete components include positioning tabs, special shapes, and other features that prevent them from being improperly assembled. The components of the chair seat may all be constructed out of suitable durable plastics, such as polypropylene, polyethylene, polycarbonate, and glass filled thermoplastics.

Abstract: A chair seat that is movable between an upright and a forward position includes a spring mechanism that biases the seat toward the upright position. The spring mechanism includes camming structures that utilize both compressional and torsional forces from the spring to bias the seat toward the upright position. The compression of the spring exerts a positive force that must be overcome before the seat can be moved out of its upright position. The chair seat is constructed from a number of discrete components that are secured together without the use of welding or separate fasteners, such as via snap-fits. The discrete components include positioning tabs, special shapes, and other features that prevent them from being improperly assembled. The components of the chair seat may all be constructed out of suitable durable plastics, such as polypropylene, polyethylene, polycarbonate, and glass filled thermoplastics.

Abstract: An ergonomic chair includes a four-bar linkage arrangement wherein a lower frame member is provided with a rigid front support and a rigid rear support with a seat member pivotably connected to the front support. A back rest has an upper support pivotably connected at an upper end of the rear support of the lower frame member. A link member pivotably connects at a first end to a rear support of the seat member and at second end to a lower support of the back rest. This novel arrangement permits tilting movement of the backrest rearwardly relative to the lower frame member causing elevation of a rear portion of the seat member, permitting the feet to remain on the floor and alleviating pressure on the user's thighs, while rotation occurs closely coincident with the pivot axis of the user's hips and while maintaining a generally uniform gaze line.

Abstract: A chair back is disclosed and includes a mesh material connected to a two-piece carrier, the carrier being deformable and stretchable. The carrier has a bottom edge including a groove and is engageable by tabs attached to a transverse member of a chair frame assembly. The upper ends of the carrier each includes an opening for receiving a spherical end portion of the upper end of the chair frame assembly. Engagement of the carrier with the chair frame assembly is accomplished by stretching the carrier and mesh between the transverse member and the spherical end portions. The chair back includes a lumbar support which is mounted to slide along the side edges of the carrier and along vertical supports of the chair frame assembly, the lumbar support causing the chair to tension forwardly. The chair back is pivotal under the influence of a chair user and is pivotally connected to the chair seat so as to cause the chair seat to also pivot in response.

Abstract: A back for a chair includes fabric panel with a flexible carrier attached to the panel around its periphery. The carrier is configured to be secured along a bottom edge to a bottom portion of a chair back frame member. The carrier is also secured to two vertical frame supports at its two upper corners. Preferably, the upper carrier and frame connections are ball and socket joints. A lumbar support is provided that is easily height adjustable, by providing tension to the back frame and requires no screws or adjustment knobs in its adjustment mechanism.

Abstract: A plastic contoured seat back includes an inner and an outer shell affixed together. The inner shell includes a three dimensionally curved front surface and a two dimensionally curved back surface. The inner shell may include an internal rib adjacent the top of the shell that is shaped differently from the top edge of the inner shell. The internal rib is adapted to allow the inner shell to be cut adjacent the internal rib so that the inner shell can be varied in shape. The shell may also include indentations on the back side of the shell adjacent the corners of the inner shell. The indentations are dimensioned to receive overlapping fabric that is pulled around the corners such that the fabric on the back of the shell adjacent the corners does not project outwardly more than the fabric elsewhere, despite the over lapping of the fabric at the corners.

Abstract: A plastic contoured seat back includes an inner and an outer shell affixed together. The inner shell includes a three dimensionally curved front surface and a two dimensionally curved back surface. The inner shell may include an internal rib adjacent the top of the shell that is shaped differently from the top edge of the inner shell. The internal rib is adapted to allow the inner shell to be cut adjacent the internal rib so that the inner shell can be varied in shape. The shell may also include indentations on the back side of the shell adjacent the corners of the inner shell. The indentations are dimensioned to receive overlapping fabric that is pulled around the corners such that the fabric on the back of the shell adjacent the corners does not project outwardly more than the fabric elsewhere, despite the over lapping of the fabric at the corners.

Abstract: A plastic contoured seat back includes an inner and an outer shell affixed together. The inner shell includes a three dimensionally curved front surface and a two dimensionally curved back surface. The inner shell may include an internal rib adjacent the top of the shell that is shaped differently from the top edge of the inner shell. The internal rib is adapted to allow the inner shell to be cut adjacent the internal rib so that the inner shell can be varied in shape. The shell may also include indentations on the back side of the shell adjacent the corners of the inner shell. The indentations are dimensioned to receive overlapping fabric that is pulled around the corners such that the fabric on the back of the shell adjacent the corners does not project outwardly more than the fabric elsewhere, despite the over lapping of the fabric at the corners.