The invention relates to a seat (1), in particular an office chair, comprising a seat support (3) for a seating surface (6) and comprising a backrest support (4) of a backrest (5), which is held on the seat support (3) so as to be able to move in a tiltable manner to the side, wherein the backrest support (4) comprises two support arms (4a, 4b) which are configured to be flexible and/or articulated laterally and spaced apart from one another. Preferably, the seating surface (6) and/or the backrest (5) comprises a curved seat shell and/or backrest shell (6a, 5a) provided with a cover (6b, 5b) with a number of flexible curved ribs (15, 16) on the edge of the shell, wherein the cover is stretched by the seat shell and/or backrest shell (6a, 5a) such that when the cover (6b, 5b) is loaded, the bending of the curved ribs (15, 16) is altered.

A chair includes a base structure, a seat support structure, a back frame comprising a front surface, a rear surface and a forwardly extending bottom portion pivotably connected to the base, a biasing member biasing the back frame from a reclined position toward an upright position, wherein the biasing member is located entirely forward a rearward most edge of the seat support structure, and a back shell comprising a forwardly extending bottom portion connected to the seat support structure, a front surface, a rear surface positioned in front of the front surface of the back frame, a pair of laterally spaced side portions defining an opening therebetween, and a top portion extending laterally between and connected to the side portions, wherein each of the side portions are exclusively connected to the back frame at a first location.

In a configuration in which a holder holding a controller is mounted on a seat part with a plate-shaped member, the exposure of the mounting part of the plate-shaped member on which the holder is mounted is eliminated. A seat device includes a pressure sensor measuring a value relating to the seated person's state, a vibration imparting device a vibration imparting operation, an ECU controlling the vibration imparting device corresponding to the measurement result of the pressure sensor, a holder holding the ECU, and a mounting bracket fixed to a lower frame such that the holder is mounted on the lower frame of a seat part. The mounting bracket includes a mounting projection on which a side wall of the holder is mounted in a predetermined mounting direction. When the side wall is mounted on the mounting projection, the mounting projection is covered with the side wall.

In a configuration in which a holder holding a controller is mounted on a seat part with a plate-shaped member, the exposure of the mounting part of the plate-shaped member on which the holder is mounted is eliminated. A seat device includes a pressure sensor measuring a value relating to the seated person's state, a vibration imparting device a vibration imparting operation, an ECU controlling the vibration imparting device corresponding to the measurement result of the pressure sensor, a holder holding the ECU, and a mounting bracket fixed to a lower frame such that the holder is mounted on the lower frame of a seat part. The mounting bracket includes a mounting projection on which a side wall of the holder is mounted in a predetermined mounting direction. When the side wall is mounted on the mounting projection, the mounting projection is covered with the side wall.

A pivoting mechanism with a first member, a second member pivotally engaged with the first member to pivot about a pivot axis, and pivoting resistance mechanism with a spring housing disposed in the first member spaced from the pivot axis, a spring disposed in the spring housing, and a deflecting member that projects from the second member spaced from the pivot axis to engage the spring disposed in the spring housing. The first member can be a chair mechanism body, and the second member can be a pivoting support, such as for a chair bottom or back. A height adjustment mechanism has a movable member, and a locking member, such as a screw, can be operative as a height locking mechanism with a first, restraining condition wherein actuation of the movable member is prevented and a second, non-restraining condition wherein actuation of the movable member is permitted.

An oscillation system (1) for chairs includes a backrest support (3) oscillating about a rotation axis (4), a first support element (6) of the seat coupled to the frame (2) to assume, in the at rest position of the backrest support (3), a plurality of relative vertical positions with respect to the frame (2) depending on, and by effect of, a weight force applied to the first support element (6). A first elastic element (21) opposes an elastic reaction to the backrest support oscillation with respect to an at rest position of the backrest support (3). A lever (31) connects to the first support element (6) to be rotated by the first support element (6) during variation of the relative position, and connects to the first anchoring end (22) to displace the first anchoring end (22). A fulcrum axis (60) does not coincide with the rotation axis (4).

An arm assembly includes an arm support configured to support an arm of a seated user, an arm stalk extending downwardly from and supporting the arm support, an arm base telescopingly receiving the arm stalk between a first position and a second position and a bearing arrangement positioned between the arm stalk and the arm base. The bearing arrangement includes a bearing member configured to abut the arm base, and a biasing member configured to bias the bearing member from the arm stalk and into abutment with the arm base.

A support for a piece of seating furniture provides an additional degree of freedom of movement. The support has a connecting unit fitted on a main body that connects to a supporting element of an underframe. The connecting unit has a mounting device for the supporting element, in particular a mount for the upper end of the supporting element. The connecting unit is fitted on the main body such that it is possible to alter the inclination of the main body relative to the supporting element. For that purpose the main body has a preferably convex contact base, which in the fitted state is contacted by a contact head of the connecting unit, with the abutment forming a non-planar contact rather than a contact over a surface area, in particular a punctiform contact.

A seating arrangement includes a base member, and an integrally formed support member coupled to the base member and supporting a seat moveable from an upright position to a reclined position, wherein a portion of the support member is bendable as the seat moves from the upright position to the reclined position such that a first side of the support member is put in tension and a second side generally opposite the first side is put in compression, and wherein the first side includes a tensile substrate so that the first side has as higher modulus of elasticity than the second side.

A reclining control system for a chair having a back and a seat including a rigid seat member having a bottom surface and a first rigid link having a first end and second end. The first end of the first rigid link may be adapted to engage the back and the second end of the first rigid link may be positioned proximally adjacent to the bottom surface of the rigid seat member. A rigid link may have a first end and a second end, where the first end of the rigid link may engage the bottom surface of the rigid seat member at an engagement point. The second end of rigid link may engage the second end of the first rigid link in an aft position. The reclining control system for a chair may further include a pivoting link having a first end and a second end. The first end of the pivoting link may engage the bottom surface of the rigid seat member at the engagement point and the second end of the pivoting link may engage the second end of the first rigid link in a fore position. The rigid link moves the rigid seat member from a non-reclining position in a downward and backward direction and the pivoting rigid link moves the back to a reclining position.