There is noticed a dynamic frame of the chair, which comprises a seat holder (1), to which a swivel sleeve (3) is demountably attached from one side, into which a spherical head (41) of a spherical thread swivel (4) with a threaded end piece (42) is tightly seated, to which a nut (7) is demountably attached and to which a silent block bushing (2) is demountably attached from the other side, to which an annular locking ring (6) with four locking undercuts (61) and four locking noses (62) is demountably attached from one side and a frame sleeve (5) with a sliding hole (53) and four sleeve noses (51) and four sleeve reinforcement pieces (52) is detachably fastened from the other side.

A resilient backrest dampening mechanism is provided for use with chairs having a seat and a backrest, the mechanism comprising four pivot points; a first pivot point arranged on a base different from the backrest; a second pivot point arranged at a distance from the first pivot point on the base, wherein a bracket is pivotally connected to the second pivot point; a third pivot point provided between the bracket and a first end of a backrest connection member, and the backrest connection member being adjustably connected to the backrest; a fourth pivot point provided in the bracket; a resilient member arranged between the fourth pivot point and the first pivot point, and wherein all the pivot points pivot around corresponding axes and all of the axes are parallel.

An adjustable chair can support an occupant that sits on a front portion of a seat cushion. When the user leans back, the chair can provide back support without requiring that the user slide rearwardly along the seat cushion, thereby providing back support to minimize, limit, or substantially eliminate lower back fatigue, discomfort, or the like. A back support of the chair can be located at a desired forward/rearward position based on the user's position on the seat. In some settings, the chair can be used by a card dealer who tends to sit on a forward portion of the seat when dealing cards. The back support can be positioned to comfortably support the dealer's back when, for example, the dealer sits generally upright. The chair can also be used by other individuals that frequently sit on the front of the seat cushion.

A chair for providing seating support to a user and for providing ways for the user to perform exercises. The chair includes a back support that is flexible such that when a force is applied to it by the user's body, the back support bends. The back support may be configured to adapt to the curvature of the user's spine when the user is seated in the chair. The back support may further be configured such that the user can rotate the back support by rotating the user's upper body.

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 includes, a seat, a backrest separated from the seat, and an upper support frame to which the backrest is attached at a position higher than the seat. In the chair, the upper support frame includes a left side portin and a right side portions both extending forward at left and right sides of the seated person and a rear portion that continuously and integrally connects the left side portion and the right side portion. The left side portion and the right side portion are connected to side support bodies arranged on left and right sides of the seat to be tiltable, and the backrest is connected to the upper support frame to be tiltable rearward.

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 seating furniture includes a seat with a seat surface, a pedestal and a tilt mechanism. The tilt mechanism is disposed between the pedestal and the seat and permits an inclination of the seat surface of the seat relative to the horizontal. In addition, the tilt mechanism has a lower bearing block mounted to the pedestal, and an upper bearing block fixedly connected to the seat. The lower bearing block has a convexly curved lower bearing surface on its upper side facing the upper bearing block, and the upper bearing block has a concavely curved upper bearing surface on its lower side facing the lower bearing block. The lower and upper bearing surfaces have substantially corresponding radii of curvature, so that the upper bearing block can be moved relative to the lower bearing block along the upper bearing surface. A tilt mechanism for seating furniture is also provided.

A resilient backrest dampening mechanism is provided for use with chairs having a seat and a backrest, the mechanism comprising four pivot points; a first pivot point arranged on a base different from the backrest; a second pivot point arranged at a distance from the first pivot point on the base, wherein a bracket is pivotally connected to the second pivot point; a third pivot point provided between the bracket and a first end of a backrest connection member, and the backrest connection member being adjustably connected to the backrest; a fourth pivot point provided in the bracket; a resilient member arranged between the fourth pivot point and the first pivot point, and wherein all the pivot points pivot around corresponding axes and all of the axes are parallel.

A connection assembly for a backrest, of an office or conference chair, includes a backrest structural element, a transverse support element, a transverse bearing by means of which the backrest structural element is rotatably coupled to the transverse support element in a direction perpendicular to a transverse direction, and a connection portion connecting the transverse support element to the backrest structural element, arranged and formed so that the backrest structural element is resiliently movable relative to the transverse support element.