Disclosed is a chair seat board (100) and a chair (1000) to which a chair backboard (200) is coupled. The chair seat board (100) may comprise: a frame unit 40 having a plurality of frames (41, 42, 43, 44) configured in a hollow shape, respectively, and implemented to allow independent movement; and a support unit configured to support the frame unit 40 while being coupled to the frame unit (40) on a lower side of the frame unit (40).

A locker includes a pair of spaced-apart upstanding sidewalls having a pair of front edges. A generally horizontal seat extends between and at least partially forward of the front edges of the sidewalls. A lower seatback is positioned between the sidewalls and extends above the horizontal seat, the lower seatback is movable between an open position and a closed position using first lateral and vertical guides. An upper seatback is positioned between the sidewalls and extends above the horizontal seat and the lower seatback, the upper seatback is movable between an open position and a closed position using second lateral and vertical guides. Lateral guides include frame guides, structurally reinforced drawer slides, hinges, or runners. Vertical guides include frame guides, runners, or vertical lift mount assemblies. The seatback assembly at least partially covers a ventilated storage compartment.

The disclosure relates to the field of seat design and manufacture, in particular to a lumbar support seat. The disclosure is achieved by the following technical solution: a lumbar support seat, comprising a lumbar support and a gas spring; the lumbar support closely fits with the back of human body through the expansion of the gas spring when the back is moved, to provide continuous and uniform uplift force. An object of the disclosure is to overcome defects of the prior art and provide a lumbar support seat. When the user moves on the seat back and forth, the lumbar support may move synchronously in contact with the back of the human body, to fit with the waist in real time, thereby increasing the supporting force in waist position of the human body.

A flexible backrest for a folding chair includes a flexible backrest panel which can assume a curved configuration of use and an extended storage configuration. The flexible backrest panel has a support surface having a concave shape in a cross-section in a horizontal plane, and a convex shape in a cross-section in a vertical plane; and the flexible backrest panel has a plurality of vertical through-slits forming a plurality of vertical slats.

A chair waist backrest height adjusting device includes a chair backrest bracket above the backrest, a worm rotated by turning the adjusting rod to slightly lower position, a first gear that is engaged with it and a second gear that is coaxially rotated with the first gear, and the chair backrest bracket under the backrest is provided with a waist backrest that can be slid up and down. The back of the waist backrest is provided with a tooth-row that is engaged with the second gear, so that the seated person on the chair can stretch out one or two hands to the adjustment rod for the forward or reverse turning operation, and the waist backrest can easily drive the waist backrest up and down, further the waist backrest is more easily adjusted, and there will be no displacement in the adjusted waist backrest.

According to the present invention a back for a seating unit is provided. The back comprises a plurality of flexible finger elements. Each of the plurality of flexible finger elements has a distal end. The back further comprises a retainer connecting at least two of the flexible finger elements proximate their distal ends. When a load is applied to a flexible finger element, the retainer distributes at least a portion of the load to at least one adjacent flexible finger element.

An ergonomically improved chair in which the user's thoracic region is supported by a narrow and generally flat or moderately convex thoracic cushion in the midrest region of the chairback. The design omits or greatly minimizes support for the user's scapulae and other areas of the back outside the thoracic region, excepting lumbar and cervical support features in some embodiments. The design differs from the prior art at least in that the thoracic cushion is narrow and configured not to complement that user's spinal curvature. By appropriate selection and design, a chair incorporating the invention may comprise a fabric covering portions of the chairback without significantly affecting functionality. Other embodiments include a chairback comprising regions having differing levels of firmness and/or differing cushion height at appropriate regions to promote concentrated support of the user's thoracic region.

A displacement auxiliary device for an accessory of a chair is revealed. The auxiliary device is disposed on the chair and used in combination with the accessory of the chair such as an armrest, a lumbar support, a headrest, etc. The auxiliary device includes a displacement member, a fixing plate and a loading plate. The displacement member further includes two rotating members that are rotated a large angle around two rotary shafts respectively and symmetrically to be moved inward to a first position or extended outward to a second position. The accessory of the chair stays still without displacement when the two rotating members are moved inward to the first position. The accessory of the chair moves synchronously while the two rotating members are extended outward to the second position. Thereby the accessory of the chair can be adjusted to have larger displacement.

A displacement auxiliary device for an accessary of a chair is revealed. The auxiliary device is disposed on the chair and used in combination with the accessary of the chair such as an armrest, a lumbar support, a headrest, etc. The auxiliary device includes a displacement member, a fixing plate and a loading plate. The displacement member further includes two rotating members that are rotated a large angle around two rotary shafts respectively and symmetrically to be moved inward to a first position or extended outward to a second position. The accessory of the chair stays still without displacement when the two rotating members are moved inward to the first position. The accessory of the chair moves synchronously while the two rotating members are extended outward to the second position. Thereby the accessory of the chair can be adjusted to have larger displacement.

The disclosure relates to the field of seat design and manufacture, in particular to a lumbar support seat. The disclosure is achieved by the following technical solution: a lumbar support seat, comprising a lumbar support and a gas spring; the lumbar support closely fits with the back of human body through the expansion of the gas spring when the back is moved, to provide continuous and uniform uplift force. An object of the disclosure is to overcome defects of the prior art and provide a lumbar support seat. When the user moves on the seat back and forth, the lumbar support may move synchronously in contact with the back of the human body, to fit with the waist in real time, thereby increasing the supporting force in waist position of the human body.