Some embodiments relate to a chair including a base, a hub, and a seat frame. The hub is supported by the base and includes first and second side mounts and first and second covers. The first side mount is positioned on a first side of the chair and includes a back portion and a bottom portion. The first cover is coupled to the first side mount to define a first channel with the first side mount. The seat frame includes a first lateral member having a lower portion and an upper portion that is pivotally coupled to the back portion of the first side mount and is configured to angulate relative to the lower portion. The lower portion of the first lateral member is slidably received in the first channel such that two sides and a bottom of the lower portion received within the first channel are substantially hidden.

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.

A body support structure includes a base, a seat and a backrest, with the backrest connected to the base with a torsion leaf spring. The torsion leaf spring may be configured with a plurality of fingers, and/or one or more flex regions. One or more struts may be connected between the seat or backrest and the base. In another aspect, the seat and/or backrest may be supported with one or more links that provide a counter-intuitive motion. In another aspect, a link may be coupled to a support with a flexible blade.

A body support structure includes a base, a seat and a backrest, with the backrest connected to the base with a torsion leaf spring. The torsion leaf spring may be configured with a plurality of fingers, and/or one or more flex regions. One or more struts may be connected between the seat or backrest and the base. In another aspect, the seat and/or backrest may be supported with one or more links that provide a counter-intuitive motion. In another aspect, a link may be coupled to a support with a flexible blade.

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.

An assembly for a chair and a chair including the same are provided. The assembly includes a body coupled to an upper portion of a leg of the chair, a pair of supports extending forward from opposite sides of the body and coupled to a bottom surface of a seating part, and a pair of connecting frames extending backward from the opposite sides of the body, bent upward, and shaft-coupled to the opposite sides of the body and the seating part. A tilting operation is performed to rotate downward the seating part and a backrest to adjust inclinations of the seating part and the backrest using a weight of a user applied to the seating part and elastic force of the support and the connecting frame.

A chair includes a seat surface and a laterally pivotable backrest. The backrest is secured to two joints, which have mutually parallel axes of rotation.

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.

The invention relates to a chair, in particular an office chair, comprising a seat surface and a laterally pivotable backrest, wherein the backrest is secured to two joints, which have mutually parallel axes of rotation.

A chair includes a seat and a backrest connected to a leg assembly. The front part of the seat is mounted on the leg assembly via a pivot link about an axis. The backrest is connected to the seat by a flexible intermediate part fixed to the leg assembly in the vicinity of the pivot of the seat for the purpose of a pivoting movement of the intermediate part by elastic deformation about an axis. The rear part of the seat is supported by the intermediate part, for example with at least one coupling element.