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.

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.

A chair includes a leg 1, a seat 5 including a pressure receiving surface PS, a backrest 6, and a support mechanism SM. The seat 5 can move in the front-rear or left-right direction along a predetermined trajectory and to downwardly incline a tip side of the seat 5 in a movement direction in accordance with a movement of the seat 5 from a predetermined reference position (S). The support mechanism SM includes a return-force generation unit configured to generate, in accordance with an amount of movement, a return force in a direction in which the seat 5 moved from the reference position (S) in the front-rear or left-right direction is returned to the reference position (S), and movably supports the backrest 6 in the left-right direction together with a movement of the seat 5 in the left-right direction.

A chair includes a leg 1, a seat 5 including a pressure receiving surface PS, a backrest 6, and a support mechanism SM. The seat 5 can move in the front-rear or left-right direction along a predetermined trajectory and to downwardly incline a tip side of the seat 5 in a movement direction in accordance with a movement of the seat 5 from a predetermined reference position (S). The support mechanism SM includes a return-force generation unit configured to generate, in accordance with an amount of movement, a return force in a direction in which the seat 5 moved from the reference position (S) in the front-rear or left-right direction is returned to the reference position (S), and movably supports the backrest 6 in the left-right direction together with a movement of the seat 5 in the left-right direction.

The invention relates to an active dynamic seating (1) comprising a foot part (2) and a pendulum joint (10) which is rotatably mounted relative to the foot part (2), a seat (3) which is rotatably mounted relative to the foot part (2), and a pendulum column (4) supporting the seat (3), said pendulum column (4) being connected for conjoint rotation with the pendulum joint (10). The pendulum column (4) is designed to be resilient in a height direction H and the pendulum column (4) is provided with anti-rotation means (51, 52, 53) which rotationally immobilize the pendulum column (4) relative to the seat (3) such that the pendulum column (4) and the seat (3) can be rotated relative to the foot part (2) only together with the rotatable pendulum joint (10).

The invention relates to an active dynamic seating (1) comprising a foot part (2) and a pendulum joint (10) which is rotatably mounted relative to the foot part (2), a seat (3) which is rotatably mounted relative to the foot part (2), and a pendulum column (4) supporting the seat (3), said pendulum column (4) being connected for conjoint rotation with the pendulum joint (10). The pendulum column (4) is designed to be resilient in a height direction H and the pendulum column (4) is provided with anti-rotation means (51, 52, 53) which rotationally immobilize the pendulum column (4) relative to the seat (3) such that the pendulum column (4) and the seat (3) can be rotated relative to the foot part (2) only together with the rotatable pendulum joint (10).

A movable human support structure has a support against which at least a part of a human can be borne in use, a base, and a first motion transmitting assembly acting between the support and the base. The first motion transmitting assembly has at least one link member connecting between the base and the support. The at least one link member is configured to be movable: a) relative to the support around a first axis; and b) relative to the base around a second axis. The first and second axes are non-parallel to each other. The first motion transmitting assembly is configured to guide movement of the support relative to the base in opposite directions in a non-straight path.

A reclinable office chair includes a reclination adjustment unit disposed at the bottom of the office chair. The reclination adjustment unit balances itself on the floor properly, resiliently and steadily. The office chair tilted in a forward-backward direction and/or a left-right direction displays directional stability relative to the floor in a manner not to lose the directional stability even when a sitter tilts in any direction, thereby allowing the office chair to provide a comfortable seat for the sitter to sit on, regardless of whether the office chair is upright or tilted in any direction.

An apparatus for sitting, including: a keystone assembly which connects various parts of the apparatus; a back that provides support for at least a person's back or shoulders; a floating lumbar support, which provides support for a person's lower back, attached to the keystone assembly; a seat that can adjust between a forward tilted and reclined position; a plurality of rollers, disposed on the keystone assembly, on which the seat rests; a central column, attached to the keystone assembly, on which the seat can spin; and a lower torsion spring connected to the seat and disposed on the keystone assembly allowing controlled movement of the seat.

An apparatus for sitting, including: a keystone assembly which connects various parts of the apparatus; a back that provides support for at least a person's back or shoulders; a floating lumbar support, which provides support for a person's lower back, attached to the keystone assembly; a seat that can adjust between a forward tilted and reclined position; a plurality of rollers, disposed on the keystone assembly, on which the seat rests; a central column, attached to the keystone assembly, on which the seat can spin; and a lower torsion spring connected to the seat and disposed on the keystone assembly allowing controlled movement of the seat.