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).

A chair can include a chair back, or backrest, that is coupled to a base of a chair above a seat of the chair. A tilt mechanism can attach the backrest to the base at spaced apart locations. In some embodiments, the tilt mechanism can be configured so that the backrest rotates about multiple pivots as it reclines from an upright position to a reclined position to drive forward motion of the seat during recline of the backrest.

An office chair comprises a seat element (3) mounted movably on a fixed support element (1) and a back support element (2). The arrangement simultaneously allows the seat element (3) to move and tilt backwards when the user leans backwards. The seat element (3) carries the chair seating panel (4) in such a way that when the user leans to a side, said chair seating panel (4) tilts to the same side according to the user's movement and independently of the chair's back element (2).

An elastic seesaw-type tilting mechanism is provided, including: a base support, configured to be connected with a chair base through a chair column; a seat support, being pivotably mounted on the base support and configured to be connected with a seat; a backrest support, being pivotably mounted on the base support and configured to be connected with a backrest; a first elastic mechanism, being connected with the seat support and the backrest support to form an elastic seesaw mechanism; a second elastic mechanism, being connected with the base support and the seat support, the second elastic mechanism and the first elastic mechanism being respectively biased against the seat support in opposite directions. A swivel chair is further provided, including: one of the elastic seesaw-type tilting mechanism as described above, a seat, a backrest, a chair column and a chair base.

A tilting mechanism (1) for chairs includes a support frame (2), a structure (4) rotationally coupled to the support frame. An elastic system (80) is interposed between the support frame and the structure to counteract a reaction to the tilting of the structure from an at-rest position to a tilted position. An adjustment system (20) is capable of varying the reaction to the tilting. The elastic system (80) includes at least one elastic element (12) and a first and a second stop element (81, 82) fastened at respective longitudinal end portions of the elastic element, respectively. In the at-rest position, the first and second stop elements are in contact with each other, and the elastic element (12) is in a deformed configuration and generates a residual elastic force that is at least partially released on the first and second stop elements.

An office chair comprises a seat element (3) mounted movably on a fixed support element (1) and a back support element (2). The arrangement simultaneously allows the seat element (3) to move and tilt backwards when the user leans backwards. The seat element (3) carries the chair seating panel (4) in such a way that when the user leans to a side, said chair seating panel (4) tilts to the same side according to the user's movement and independently of the chair's back element (2).

A seat structure comprises a base configured to be a chair base assembly; a seat support located above the base, wherein a front part of the seat support has rotary connection with the front part of the base through a transition link; a chair back assembly having rotary connection with a rear part of the base through a pivot; a lever driving member linked between the chair back assembly and the seat support, and having rotary connection with a rear part of the seat support, wherein the lever driving member and the seat support are approximately on the same surface. When the chair back assembly rotates rearward around the pivot from the initial position, the rear part of the seat support is raised diagonally to the rear through the lever driving member, meanwhile the transition link and the front part of the seat support are pulled up.

A synchronous chair mechanism (10) for simultaneously changing a seat and a backrest of a chair from a zero position in which the backrest is tilted to a minimum extent relative to the seat, into an end position in which the backrest is tilted to a maximum extent relative to the seat, includes a base (20) that is connectable to a substructure provided for setting up the chair. The synchronous chair mechanism also includes a backrest carrier (30) on which the backrest is mountable, a seat support (40) that is designed for holding a seat, and a spring element (8) having a front end and a rear end. The backrest carrier (30) is mounted on the base (20) so as to be pivotable about a first rotational axis (710). The seat support (40) is connected to the backrest carrier (30) so as to articulate about a second rotational axis (720), and is connected to the front end of the spring element (80) so as to articulate about a third rotational axis (730). The rear end of the spring element (80) is hinged to the backrest carrier (30) via a fourth rotational axis (740). A latching structure (310) is formed on the backrest carrier (30). The synchronous chair mechanism (10) includes a slide coupling piece (60) that is mounted on the rear end of the spring element (80) so as to be pivotable about the fourth rotational axis (740). Outside the zero position of the synchronous chair mechanism (10), the slide coupling piece (60) engages with the latching structure (310) of the backrest carrier (3; 30) so that the slide coupling piece (60) and the backrest carrier (30) are fixedly connected to one another. In the zero position of the synchronous chair mechanism (10), the slide coupling piece (60) is decoupled from the latching structure (310) of the backrest carrier (30) so that the slide coupling piece (60) is movable relative to the latching structure (310), as the result of which a distance between the fourth rotational axis (740) and the first rotational axis (710) is changeable.

A chair can include a chair back, or backrest, that is coupled to a base of a chair above a seat of the chair. A tilt mechanism can attach the backrest to the base. In some embodiments, the tilt mechanism can be configured so that the backrest rotates about multiple pivots as it reclines from an upright position to a reclined position to drive motion of the seat during recline of the backrest.

A motion seat is described that includes a chassis, a seat frame, a seat cushion, a backrest, and a resilient hinge. The seat frame is attached to the chassis and the seat cushion and the backrest are each attached to the seat frame. The resilient hinge formed as a unitary body and may be formed from a resilient polymer. The seat cushion and/or the backrest is pivotably attached to the seat frame with the resilient hinge.