A (recliner) chair action of relatively movable seat frame (11), (back) drive frame (12) and yoke frame (13), with intervening links (16, 17, 18, 19), independently grouped respectively between seat frame and drive frame and between drive frame and yoke frame; for seat translation and elevation upon back recline operable under a potential energy function in an inter-relationship between back recline and seat movement, for a common or harmonious experience between different occupancy weights.

A mechanism for an office chair has a base support which is placeable on a chair column. A seat support is arranged on the base support and is movable relative to the base support. A backrest support is coupled with the seat support. Pivoting the backrest causes the seat support to move relative to the base support. An alternative solution for adjusting the tilting resistance of the seat support of an office chair is provided where the tilting resistance of the seat support is influenced by the pivoting resistance of the backrest support.

An office-type chair includes a weight responsive mechanism having a front link pivotally connected between the base and the seat, a rear link pivotally connected between the seat and the backrest, and a resilient element, wherein the force of a user occupying the seat pivots the front link and the rear link against a resistance created by the resilient element an amount proportional to the weight of the user to increase the effective length of the moment arm between the user and the recline axis, such that the force to pivot the backrest about the recline axis varies as a function of the weight of the user. In one embodiment, a secondary recline spring between the base and the backrest, the secondary spring contributing to the biasing force of the recline tension spring when the backrest is moved to the reclined position.

An office chair mechanism includes a base support for placement on a chair column, a seat support on the base support being movable relative to the base support and a backrest coupled to the seat support. Pivoting the backrest moves the seat support relative to the base support. A track element is movably connected at a base support connecting point to the base support and at a seat support connecting point to the seat support to adjust pivoting resistance of the backrest. Pivoting the backrest alters position and/or location of the track element. A spring element acting on the track element and on the seat support or on the backrest and/or a backrest support is acted upon with a movement of the seat support relative to the base support. An adjustment device alters the position of a point of action of the spring element on the track element.

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 method of assembling a spring inside of a tube includes providing a coil spring and a tube having a first retaining structure at a first end of the tube. The method includes positioning a rod in the tube. The spring is positioned in the tube, and a second retaining structure is attached to the rod with the spring positioned between the first and second retaining structures. A force is applied to the spring, and the second retaining structure is fixed at a position wherein the spring provides a desired preload.

A seat back plate adjustment device includes a connection mechanism sleeved on a seat base lifting cylinder, a swinging mechanism fixedly provided on the connection mechanism and an adjustment mechanism penetrating the connection mechanism; the swinging mechanism includes a spring support fixedly provided on the connection mechanism, two swinging springs symmetrically set about a center line of the spring support, an insertion plate and a rotating shaft pressed against the swinging springs; the rotating shaft runs through the insertion plate and the spring support, the insertion plate is rotatably connected with the spring support, and the insertion plate is fixedly connected to the back plate of the seat. The invention has the advantages of good sitting comfort and good support stability.

A theater chair comprises a flip-up/flip-down seat, a reclining backrest, and a reclining seat. An actuator is operatively connected to the reclining backrest for moving the backrest and seat from a normal or default upright position to any one of a multitude of reclined positions. The flip-up/flip-down seat is provided with a spring for returning the seat to its upright position when the seat is unoccupied. A sensor is operatively associated with the seat so as to effectively monitor the orientation of the seat. When the seat is vacated, the sensor will detect movement of the seat and send an appropriate signal to a control circuit which is operatively connected to the actuator. After a predetermined period of time, the actuator will be actuated so as to return the backrest from the reclined position to the default upright position.

A flexible support device for chair back tilting contains: a supporting frame, a seat mounting, and a base. The supporting frame includes a back portion, two peripheral extensions, two rotatable edges, two first coupling orifices, and two second coupling orifices. The seat mounting includes a first fixing portion, a second fixing portion, two connecting fences, two rotatable locating portions, two defining orifices, two joining elements, two slide orifices, and a drive protrusion. The base includes two locating fringes with two first positioning orifices, two second positioning orifices, a holder connected with a first end of a spring, and a second end of the spring is connected with a flexible sheet. The flexible sheet has two peripheral sections. The base further includes two connection segments, and the two connection segments have two openings. Two connectors are configured to accommodate the flexible sheet and have two pegs.