A pivot shaft (10) which is a first shaft member coupled to a supporting member, an inner cylinder (12) which is a second shaft member coupled to a supported member, and an outer cylinder (14) which is a third shaft member are disposed to be approximately coaxial with each other and disposed radially in multiple layers. The pivot shaft (10) and the inner cylinder (12) are coupled to each other through a first rubber-like elastic member (11), and the inner cylinder (12) and the outer cylinder (14) are coupled to each other through a second rubber-like elastic member (13). The total reaction force is increased by restricting the rotation of the outer cylinder (14) by means of an operating pin (19) which is a reaction force adjusting part and thereby adding a reaction force resulting from the second rubber-like elastic member (13) to a base reaction force resulting from the first rubber-like elastic member (11).

An electrically controlled chassis includes: a chassis body; an electrical control box, internally provided with an accommodation space; a drive motor, configured to control lift adjustment of the chassis of the chair and pitch adjustment of a backrest of the chair; a winding mechanism, connected to an output shaft of the drive motor; a first pull cord, reversely wound on the winding mechanism; a second pull cord, normally wound on the winding mechanism; a backrest adjustment mechanism, disposed on the chassis body, and fixedly connected to the other end of the first pull cord; and a chassis lift mechanism, disposed on the chassis body, and fixedly connected to the other end of the second pull cord.

An electrically controlled chassis includes: a chassis body; an electrical control box, internally provided with an accommodation space; a drive motor, configured to control lift adjustment of the chassis of the chair and pitch adjustment of a backrest of the chair; a winding mechanism, connected to an output shaft of the drive motor; a first pull cord, reversely wound on the winding mechanism; a second pull cord, normally wound on the winding mechanism; a backrest adjustment mechanism, disposed on the chassis body, and fixedly connected to the other end of the first pull cord; and a chassis lift mechanism, disposed on the chassis body, and fixedly connected to the other end of the second pull cord.

A rebounding device includes a front member, a rear member, and a junction member releasably coupling the front member and the rear member is disclosed. The junction member enables the front member and the rear member move between a collapsed position and an expanded position, and the front member is movable relative to the rear member during a rocking motion when the junction member is in the expanded position. In one embodiment, the junction member comprises a ratchet gear, a spring-loaded pawl configured to engage the ratchet gear and prevent rotation thereof, and a torsion spring. Application of pressure by a user against the front member causes the front member to move toward the rear member, thereby loading the torsion spring. Removal of the pressure against the front member causes the torsion spring to unload, thereby biasing the front member away from the rear member.

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.

A seat tilting mechanism comprising a main body, a support member rotationally mounted to said main body, and a first extension coil spring mounted between said main body and said support member to provide resistance to rotation of said support member, in which said seat tilting mechanism further comprises a second extension coil spring and an engagement mechanism which engages said second extension coil spring for resistance to rotation of said support member when said first extension coil spring reaches a pre-determined point of extension.

A chair includes a seat, a backrest, and an elastic link. The seat supports a user's buttocks, wherein the backrest supports the user's back, the elastic link elastically connects a side portion of the seat to a side portion of the backrest, the seat includes a seat free end formed at a rear portion thereof without being connected to the backrest and the backrest includes a backrest free end formed at a lower portion thereof without being connected to the seat.

Disclosed herein is a chair that includes a backrest portion, a seat portion coupled with the backrest portion, a column portion coupled with the seat portion, a linkage coupled with the backrest portion, a leaf spring in direct contact with the linkage, an arc-shaped toothed structure fixed translationally relative to the column portion, and a different toothed structure in contact with the arc-shaped toothed structure. The chair is also configured such that when a weight is applied to the seat portion, a fulcrum point of the leaf spring moves as the different toothed structure moves along the arc-shaped toothed structure to thereby shorten a working length of the leaf spring and provide an increased resistance to tilting of the backrest portion relative to the column portion. A process for assembling the chair and a weight-based tilt-resistance assembly for use with the chair are also described herein.

An adjustable rotary rocking chair having a chair frame assembly A, an adjustment mechanism B, and a support tube assembly C, wherein the adjustment mechanism B is detachably connected with the chair frame assembly A and is connected with the support tube assembly C in an insertion manner. The adjustable rotary rocking chair can swing and rotate, has higher flexibility and adaptability due to the fact that the height of the rocking chair and the height of the support tubes can be automatically adjusted by users, is portable through a folding design, and can be used indoors and outdoors.

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.