A chair assembly includes an arm assembly that includes an armrest supported by a vertically adjustable support assembly and an arm base, where the arm base extends at an acute angle with respect to a longitudinal centerline of the chair assembly, an upholstery arrangement including a ring member attached to a cover, where the ring member includes a plurality of reliefs having a width that reduces as the ring member is wrapped about a shell member of the chair assembly, and a control arrangement having a biasing member that moves through an arcuate path as the biasing member is adjusted between varying bias settings.

A chair back, belonging to the field of office furniture, comprises a stretching mechanism, and a supporting mechanism including a supporting frame, an adjusting lever and a rotor disposed on the supporting frame, a spring disposed on the adjusting lever, and a rope wound across the rotor and having an end connected to the spring and an end connected to the stretching mechanism. A sliding slot is formed in the supporting frame. An adjusting block sliding along the sliding slot is disposed in the sliding slot and connected to the adjusting lever in a threaded manner, and has a side abutting against one end of the spring. The stretching mechanism can elastically change to some extent in the stretching direction thereof, so that when moving in this direction, the back of a user will always cling to the backrest, and thus, the user feels more comfortably

A pivoting mechanism with a first member, a second member pivotally engaged with the first member to pivot about a pivot axis, and pivoting resistance mechanism with a spring housing disposed in the first member spaced from the pivot axis, a spring disposed in the spring housing, and a deflecting member that projects from the second member spaced from the pivot axis to engage the spring disposed in the spring housing. The first member can be a chair mechanism body, and the second member can be a pivoting support, such as for a chair bottom or back. A height adjustment mechanism has a movable member, and a locking member, such as a screw, can be operative as a height locking mechanism with a first, restraining condition wherein actuation of the movable member is prevented and a second, non-restraining condition wherein actuation of the movable member is permitted.

An armchair includes a base, a backrest pivotally connected to the base by a first rotating shaft, an armrest connected to the base and an elastic assembly fixed on the armrest. The backrest and the elastic assembly are pivotally connected by a second rotating shaft. The elastic assembly is configured to provide elastic force when the backrest swings around the first rotating shaft. The elastic assembly arranged between the backrest and the armrest permits the backrest to be able to swing relative to the base. In use, the elastic assembly controls the swing amplitude of the backrest according to the pressure exerted by the user's back on the backrest. When the user reclines backward, the elastic assembly acts as a cushion to support the backrest to slowly swing backward due to the elastic force. When the user rises, the elastic force of the elastic assembly urges the backrest to reset.

A reconfigurable apparatus for sitting and having a seat mounted on a frame and movable under the weight of a sitting user. As an incident of the user sitting, resistance to movement of a back rest component is increased a predetermined amount based upon the user's weight. A manually operable subassembly allows the increased resistance to be changed from the predetermined amount with the user sitting on the seat.

Adjustment device for a chair which is provided with a rocking mechanism composed of a first plate, fixed to a central gas-operated post for the height adjustment of a seat and to which a second plate is articulated, about a first axis that is transverse thereto and so that it can rock, the second plate being fixed to a seat or being integral with a seat and interacting with elements which are adapted to contrast the rocking of a backrest. A first cable is slideably associated with the first plate and is adapted to activate a lever which is articulated internally to the first plate at a different second axis and is adapted to activate the height adjustment of the seat. A second cable is further slideably associated with the first plate and is adapted to activate a mechanism which allows or prevents the rocking of the second plate.

A chair according to the present invention has a reference position P located midway in a front-back direction in a movable range of a seat 2. The chair includes a return force generation mechanism 4 configured to generate a return force in a direction to return the seat 2 moved from the reference position P at least in the front-back direction to the reference position P. The return force generation mechanism 4 includes an elastic member 40 configured to increase the return force in the direction to return the seat to the reference position P as the amount of movement of the seat from the reference position P increases.

To provide a chair in which the seated person can perceive a comfortable sitting feeling even if sitting for a long time, and furthermore a high work efficiency can stably be maintained, a chair according to the present invention includes a support mechanism 2 interposed between a leg 1 and a seat 3, wherein the support mechanism 2 includes: a seat inclining mechanism Q as a seat inclining function configured to downwardly incline a tip side in an operation direction of the seat 3 when the seat 3 operates from a predetermined reference position (S), and further includes: a return-force generation mechanism configured to generate, in accordance with an amount of movement, a return force in a direction of returning the seat 3 having moved from a reference position (S) in a front-rear or left-right direction, to the reference position (S).

An armrest device for adjusting an inclination angle of a backrest. The armrest device includes a side connecting bracket and an armrest. A lower end of the side connecting bracket is fixedly connected with a seat cushion. Right ends of the side connecting bracket and the armrest are rotatably connected with the backrest. An upper end of the side connecting bracket is fixedly connected with a positioning seat. An upper end of the positioning seat extends to an inner cavity of the armrest. The positioning seat shifts the inclination angle of the backrest and limits a position of the backrest through a positioning mechanism. A first spring limiting a movement of the armrest in an X direction and a second spring limiting a movement of the armrest in a Z direction are disposed between the positioning seat and the armrest.

A body support structure includes a frame and a membrane attached to the frame. The membrane includes elastomeric filaments. The membrane includes different regions with different stiffness. The membrane may form a part of a seat or a backrest.