A chair assembly includes a back support arrangement that includes a back frame member and a forwardly-facing surface configured to support a user, a four-bar linkage assembly including a first linkage member, a second linkage member, a third linkage member and a fourth linkage member each pivotably coupled to one another such that the four-bar linkage assembly includes an upper end that is adjustable between raised and lowered positions, and an arm rest assembly supported on the upper end of the four-bar linkage assembly, wherein a lower end of the four-bar linkage assembly is pivotably supported from an arm support structure for pivotable movement such that the upper end of the four-bar linkage assembly is movable between a first position and second position located laterally outward from the first position, and wherein the fifth pivot point is located forwardly of the back frame member.

A chair assembly includes a base structure defining upper and lower portions, and a support structure, a seat support structure having a forward portion pivotably connected to the upper portion of the base structure for rotation about a first pivot point and a rearward portion, a back support structure having a forward portion pivotably connected to the lower portion of the base structure for rotation about a second pivot point that is located below and rearward of the first pivot point, and an upwardly extending back portion that moves rearwardly and downwardly as the back support structure pivots and the back portion moves, and a control link pivotably coupled to the seat support structure for rotation about a third pivot point and to the back support structure for rotation about a fourth pivot point each located rearward of the first and second pivot points.

A body support assembly includes a seat assembly and backrest assembly supported by a tilt control assembly. Methods of using and assembling the body support assembly are provided.

A chair assembly includes a seat support structure, a back support structure, a back tensioning assembly adjustable between low and high tension positions, an actuator assembly adapted to adjust the back tensioning assembly between the low and high tension positions, a control input assembly actuable by rotating the portion of the control input assembly, and a control link assembly operably coupling the control input assembly with the actuator assembly to adjust the back tensioning assembly between the low and high tension positions upon rotation of the portion of the control assembly by a seated user, wherein a number of rotations of the portion of the control input assembly is not limited by the control link.

A quickly released and fastened adjustment mechanism including a gasket, a first ratchet, a second ratchet, a T-shaped sleeve and a fastener is installed between a sliding member and a fixing member. The first and second ratchets are arranged with annular teeth respectively while the two annular teeth are engaged. The T-shaped sleeve is mounted in the first and second ratchets and against the gasket. The fastener is passed through the T-shaped sleeve, the gasket and the sliding member to be secured on the fixing member. Thus the two corresponding annular teeth are engaged firmly. The height difference between low-level and high-level engagement of the two annular teeth is H.sub.f. The sleeved height of the T-shaped sleeve is D.sub.1. The total height of the first and second ratchets in the low-level engagement is D.sub.2. D.sub.1>D.sub.2. D.sub.1D.sub.2=G>0 and H.sub.f>G>0.

A seating unit component assembly comprises a support component that includes a first surface adapted to abut a seated user, a second surface opposite the first surface, a first end surface, a second end surface opposite the first end surface, and a pair of side surfaces extending between the first and second end surfaces, and a cover having a plurality of sides that cooperate to form an interior space that receives the support component therein, wherein the cover includes a first portion comprising a non-fabric substantially flexible thermoplastic material covering at least a portion of at least one of the side surfaces of the support component, a second portion comprising a fabric covering at least a portion of the first surface and at least a portion of the first end surface of the support component, and a third portion comprising a substantially rigid overlay covering at least a portion of the second end surface and at least a portion of the second surface.

The armrest structure includes a connecting seat having a sleeve. A height adjustment rod is disposed in the sleeve and has two symmetric boards. Each of the boards is formed with recesses. A receiving room is formed between the two boards. An elevation rod is disposed in the sleeve. An end of the elevation rod has a projection received in the receiving room. Another end of the elevation rod has a connecting seat with a cylinder and a spring. An armrest set has a tube and an armrest connected atop the tube. The tube is received in the sleeve and sheathes the height adjustment rod and elevation rod. A top of the tube is formed with a channel for receiving a trigger. A fixing bar passes through the projection and is embedded into one of the recesses.

A seating unit component assembly comprises a support component that includes a first surface adapted to abut a seated user, a second surface opposite the first surface, a first end surface, a second end surface opposite the first end surface, and a pair of side surfaces extending between the first and second end surfaces, and a cover having a plurality of sides that cooperate to form an interior space that receives the support component therein, wherein the cover includes a first portion comprising a non-fabric substantially flexible thermoplastic material covering at least a portion of at least one of the side surfaces of the support component, a second portion comprising a fabric covering at least a portion of the first surface and at least a portion of the first end surface of the support component, and a third portion comprising a substantially rigid overlay covering at least a portion of the second end surface and at least a portion of the second surface.

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.

The present invention relates to a chair equipped with supporter for shoulder which can obtain an effect of attitude remedy by reducing the pressure applied to the spine and by inducing an upright attitude of erecting the waist vertically through the supporter for shoulder which is connected to the hip supporter through the base and which comprises the supporter for armpit provided above the supporter, and in addition which can maximize convenience and enable the multi-purpose use by selecting the use and non-use of the supporter for arm or the supporter for shoulder through the direction change through up-down or forward-rearward direction rotation of the supporter for arm or through the folding of the supporter for armpit of the supporter for shoulder through the rotation shaft.

The chair equipped with supporter for shoulder according to the present invention comprises: a base; a hip supporter provided above the base; a supporter for shoulder comprising a supporter connected to the base and protruding to both sides of the hip supporter, and a supporter for armpit provided above the supporter; and a supporter for arm connected to the base and provided below the supporter for armpit.