A rotatable chair back includes a lower section attachable to a chair seat, a flexible Y-shaped upper section for supporting a chair back frame, and two rigid supports extending substantially vertically into and between the upper section and the lower section. In use, the substantially vertical supports each serve as an axis of rotation about which the upper section may rotate relative to the lower section.

A tilt-swivel chair employing a bearing base assembly in communication with connection plate or seat plate of the chair is provided. The tilting mechanism in forward and backward direction is provided by the spring which has a pushing and pulling action and the swiveling action is done along the side axis of the bearing base assembly, and the side axis is a cylindrical shape section with a bushing cap onto which a lever base is equipped and is connected to the connection plate or seat plate. The balance ball feeling is provided with the spring action. A cam and lever mechanism is provided at the base of the side axis in corporation with the base section of the assembly. The cam and lever mechanism provides a smooth swiveling action to the seat and to lock and shut down and take a break.

A chair assembly includes a supporting frame disposed above a base and including a first guiding groove. A seat is pivotably connected to a backrest. Lower and front guiding wheels are mounted to rear and front ends of the seat, respectively. At least one operating board includes rear and front ends respectively having second and third guiding grooves. The lower guiding wheel is movably received in the first and second guiding grooves. The front guiding wheel is movably received in the third guiding groove. A first operating rod is pivotably connected between the supporting frame and the seat. When the operating rod retracts, the lower guiding wheel is located in rear ends of the first and second guiding grooves, and the front guiding wheel is located in a rear end of the third guiding groove. The seat moves downwards and rearwards, and the front end of the seat inclines upwards.

Elements of the present disclosure provide chair apparatus comprising: a seat comprising: a top portion configured to contact at least a portion of a user of the chair apparatus, and a bottom portion; a back support secured to the bottom portion, the back support configured to contact at least a portion of the user of the chair apparatus; a chair base comprising: a cylinder, a first end of the cylinder securing to the bottom portion of the seat, a cylinder base secured to a second end of the cylinder, one or more legs secured to the cylinder base; a table system comprising: a table arm revolvably secured to the cylinder such that the table arm is configured to axially rotate independently and undisturbed around the seat and the back support, and a table portion hingedly connected to the table arm and positioned above the top portion of the seat.

A body support assembly includes a seat assembly and backrest assembly supported by a tilt control assembly. Methods of using and assembling the body support assembly are provided.

An electrically adjustable seating device includes at least one sensor element, a processor, a memory unit and at least one electromechanical actuator. The at least one sensor element is designed to detect predetermined seating parameter data relating to a person sitting on the seating device and to transmit the data to the processor. The processor is designed to determine person parameter data, relating to the person, from the seating parameter data, to extract control data, which are associated with the person parameter data, from the memory unit and to control the at least one electromechanical actuator on the basis of the control data.

A seating arrangement includes a rigid back frame, a flexible back shell coupled to the back frame and including a pair of vertical side portions and at least two strap portions extending laterally between the side portions and including a forwardly-facing surface configured to support a back of a seated user, the at least two strap portions including a lowermost strap portion, the lowermost strap portion configured to deflect a first distance when a rearwardly-directed force is exerted on the lowermost strap portion by a seated user, and a lumbar assembly supported from the back frame and configured to support the lumbar region of a back of a seated user, the lumbar assembly configured to deflect a second distance when the rearwardly-directed force is exerted on the lumbar assembly by a seated user, wherein the first distance and the second distance are substantially similar.

A chair that can transition from an upright position to a reclined position includes a base to rest on a floor, a post upstanding from the base, a chassis affixed to a top of the post and having left and right extensions, armrests extending upward from the left and right extensions. A seat is made up of a seat pan and a seat upper support frame, which are positioned under and above the chassis respectively and has a hole through which the post extends. A backrest has a lower end pivotally joined to the seat and a pivotal connection to each of the armrests, so rearward pressure on an upper area of the backrest causes pivoting of the backrest at the armrests and at the seat, pushing the seat forward to a reclined position in a synchronous motion.

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 chair, in particular an office chair, has a seat inclination mechanism. A transverse strut of the seat inclination mechanism forms a spring device and this spring device has at least one torsion element. The seat inclination mechanism further has a basic support on which a backrest support and a seat element support are articulated. The transverse strut of the seat inclination mechanism forms a spring device. The transverse strut extends in the chair transverse direction and wherein the spring device has at least one torsion element, in particular a torsion bar spring. The torsion element, together with the basic support and/or the backrest support and/or the seat element support, is formed integrally, in particular in one piece, from plastic.