Some embodiments relate to a chair including a base, a hub, and a seat frame. The hub is supported by the base and includes first and second side mounts and first and second covers. The first side mount is positioned on a first side of the chair and includes a back portion and a bottom portion. The first cover is coupled to the first side mount to define a first channel with the first side mount. The seat frame includes a first lateral member having a lower portion and an upper portion that is pivotally coupled to the back portion of the first side mount and is configured to angulate relative to the lower portion. The lower portion of the first lateral member is slidably received in the first channel such that two sides and a bottom of the lower portion received within the first channel are substantially hidden.

A tiltable chair includes a flexible seat body including an integrally formed seat back and seat surface supported on a seat frame disposed on upper parts of legs, and the seat back connected to a back frame allowing tilting rearwards, the position of the connection being in an area around the upper part of the pelvis of a person seated thereon. A guide rail having an arc-shaped groove is fixed to the seat frame, and guide members which engage and roll in the arc-shaped grooves are pivotably supported on a shaft bracket of the rear surface of the seat surface. The arc-shaped groove has a high center so that the seat surface undergoes curved motion forward and upward such that the ischium is positioned lower than the lower part of the knees when the seat back tilts rearwards.

An adjustable support assembly for use in a chair has a mounting member 602, a support 605 for supporting part of the body of a chair occupant, and a carrier 611 slidably carrying the support 605. The support has a plurality of engagement features 621 and the carrier has an engagement member 615 that is selectively engageable with the engagement features to enable the support to be selectively positioned relative to the carrier at a plurality of positions. A biasing arrangement 607 operatively connects the carrier 611 to the mounting member 603 and forwardly biases the carrier 611 and support 605. The engagement between the engagement member 615 and an engaged engagement feature 621 increases upon application of rearward force to the support.

Some embodiments relate to a chair including a base, a hub, and a seat frame. The hub is supported by the base and includes first and second side mounts and first and second covers. The first side mount is positioned on a first side of the chair and includes a back portion and a bottom portion. The first cover is coupled to the first side mount to define a first channel with the first side mount. The seat frame includes a first lateral member having a lower portion and an upper portion that is pivotally coupled to the back portion of the first side mount and is configured to angulate relative to the lower portion. The lower portion of the first lateral member is slidably received in the first channel such that two sides and a bottom of the lower portion received within the first channel are substantially hidden.

A chair assembly includes a base assembly, a seat assembly having a pair of side edges and a fore-to-aft extending longitudinal centerline, a back assembly movable between upright and reclined positions, and an arm assembly including an arm base extending from a first location between the side edges to a second location laterally outward of one of the side edges, wherein the arm base extends at an acute angle with respect to the longitudinal centerline and at an upward angle from the first location toward the second location, a support assembly supported by and extending upwardly from the arm base, and an armrest supported by the support assembly that is adjustable to support the armrest between a plurality of selected vertical positions, wherein the arm assembly and back assembly move at a different rate from one another as the back assembly is moved between the upright and reclined positions.

A chair assembly includes a base assembly, a seat assembly having a pair of side edges and a fore-to-aft extending longitudinal centerline, a back assembly movable between upright and reclined positions, and an arm assembly including an arm base extending from a first location between the side edges to a second location laterally outward of one of the side edges, wherein the arm base extends at an acute angle with respect to the longitudinal centerline and at an upward angle from the first location toward the second location, a support assembly supported by and extending upwardly from the arm base, and an armrest supported by the support assembly that is adjustable to support the armrest between a plurality of selected vertical positions, wherein the arm assembly and back assembly move at a different rate from one another as the back assembly is moved between the upright and reclined positions.

A seat adjustment module includes: a base; a stop block, configured to stop forward and backward movements of a seating member in a seat; a rotary block, configured to, in response to being rotated along a first rotation direction, drive the stop block to slide, wherein the rotary block is further configured to, in response to being rotated along a second rotation direction, open a backrest adjustment switch in the seat; a handle, rotatably connected to one end of the rotary block, and configured to, in response to being rotated with respect to the rotary block, open a lifter switch of the seat; and a twistable adjustment member, rotatably connected to the base, and configured to be connected to a backrest elastic force adjustment mechanism, wherein the twistable adjustment member is configured to adjust a magnitude of an elastic force of a backrest in the seat.

A seating arrangement may include a backrest with a shroud and/or anchor elements securing a membrane and flexible material. An actuator may operate may simultaneously operate boost/stop components acting on a tilt control mechanism of the seating arrangement. An armrest assembly may include a strap, tubular member and adapter interfacing between the strap and tubular member.

A seating arrangement may include a backrest with a shroud and/or anchor elements securing a membrane and flexible material. An actuator may operate may simultaneously operate boost/stop components acting on a tilt control mechanism of the seating arrangement. An armrest assembly may include a strap, tubular member and adapter interfacing between the strap and tubular member.