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.

A back adjusting and positioning structure of a chair is characterized in that: a backward tilt adjustment unit is disposed at the junction of a cushion frame and a back frame of the chair so that the backward tilt adjustment unit drives a screw segment with one end thereof extending inward to retract and/or protrude a blocking element coupled to a rear segment thereof in response to a knob's rotating in a predetermined direction, so as to control compression and/or expansion of a predetermined stop distance acquired by a spring fitted in the backward tilt adjustment unit, and in consequence the back in operation attains the required tightening and/or loosening state.

Embodiments provide a seat connecting device with an adjustable backrest, belonging to the technical field of swivel chairs. In the embodiments, the seat connecting device includes a seat back tightness control assembly including a control handle, a universal joint, a transmission rod, a first bevel gear, a second bevel gear, a lifting part, a mounting seat of the lifting part, and a tightness adjust rod. The present disclosure uses the universal joint to replace the original rope for transmission, improving the response timeliness of the force transmission of the product when adjusting the seat back elasticity; and improving the accuracy and controllability of the seat back elasticity adjustment. At the same time, relative to the use of rope adjustment method, the size of the force arm can be also effectively improved, the size of the force transmission of the product during regulation and the demand for the size of the force transmission are improved, the force requirements for the user is reduced, and the possibility of damage to the adjustment mechanism due to excessive input force when the product is adjusted is effectively reduced, thereby increasing the service life of the product.

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.

A tilt locking device for a chair, comprising a housing configured for connection to one of a seat and a frame; a first rotatable locking member, rotatable about a first axis and biased in a first direction about the first axis, the first rotatable locking member is configured for interlocking with a notch member; a rotatable activation member, rotatable about a second axis, the rotatable activation member is configured to abut and rotate the first rotatable locking member in a second direction opposite the first direction into interlocking with the notch member.

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 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 chair that provides movement side-to-side about a first pivot axis positioned above the seat plane allows the user a wide range of dynamic movement, but does not require constant or excessive action on the part of the user to maintain a desired position. In addition and concurrently thereto, the structure may include a second pivot that is also positioned above the seat plane and that provides forward-and-back movement of the seat. The first and second pivot axes can be engaged synchronously or independently by the user as desired delivering infinite degrees of angles of movement. Said pivot axes are more closely adjacent to the human body pivot joints and axes. The seat and seat back may be joined together to a central spine frame that moves about the second pivot, thereby maintaining the seatback position and seat position relative to each other during forward-and-back movement of the spine along the second pivot. One or more biasing structures may be provided to urge the seat into forward-and-back and side-to-side neutral positions. If desired, the location of this forward-and-back neutral position can be statically adjusted by a user, and at least one of the biasing structures can hold this forward-and-back neutral position at a desired tension level thereby allowing a user to select the amount of force required to move the seat out of this defined forward-and-back neutral position. Moreover, an adjustment structure may be provided that allows for static adjustment of the seatback's position on the spine.

A spring member is disposed so that a biasing direction is in a forward/rearward direction, and includes a front side engagement portion disposed on a front portion of the spring and a rear side engagement portion disposed on a rear portion of the spring, a seat includes a front side spring receiving portion engaged with a front side engagement portion, a backrest or a support structure includes a rear side spring receiving portion engaged with the rear side engagement portion and an adjustment portion configured to adjust a position of the rear side engagement portion in the upward/downward direction together with the rear side spring receiving portion, and an upper limit position of the rear side engagement portion of the spring member adjusted by the adjustment portion is located above an pivot axis at which the backrest is rotatably supported by the support structure.