A tiltable chair includes a flexible seat body including an integrally formed seat back and seat surface is supported on a seat frame disposed on upper parts of legs, and the seat back connected to a back frame allowing tilting rearwards, the position of the connection being in an area around the upper part of the pelvis of a person seated thereon. A guide rail having an arc-shaped groove is fixed to the seat frame, and guide members which engage and roll in the arc-shaped grooves are pivotably supported on a shaft bracket of the rear surface of the seat surface. The arc-shaped groove has a high center so that the seat surface undergoes curved motion forward and upward such that the ischium is positioned lower than the lower part of the knees when the seat back tilts rearwards.

A tiltable chair includes a flexible seat body including an integrally formed seat back and seat surface is supported on a seat frame disposed on upper parts of legs, and the seat back connected to a back frame allowing tilting rearwards, the position of the connection being in an area around the upper part of the pelvis of a person seated thereon. A guide rail having an arc-shaped groove is fixed to the seat frame, and guide members which engage and roll in the arc-shaped grooves are pivotably supported on a shaft bracket of the rear surface of the seat surface. The arc-shaped groove has a high center so that the seat surface undergoes curved motion forward and upward such that the ischium is positioned lower than the lower part of the knees when the seat back tilts rearwards.

A chair chassis includes: a base, provided with an accommodation chamber; a backrest support; a memory stopper, disposed on the backrest support, wherein the memory stopper is provided with a first arc surface facing the base; a locking slider, slidably disposed in the accommodation chamber of the base, wherein the locking slider is provided with a second arc surface disposed opposite to the first arc surface, and a side of the locking slider is provided with a first rack; a first elastic member; and an elastic slider, slidably disposed in the accommodation chamber of the base, wherein one end of the elastic slider is provided with a second rack, wherein the second rack is meshable with the first rack. Accordingly, the chair chassis according to the embodiments of the present disclosure achieves reclination memory adjustment of a backrest of the chair.

A chair chassis includes: a base, provided with an accommodation chamber; a backrest support; a memory stopper, disposed on the backrest support, wherein the memory stopper is provided with a first arc surface facing the base; a locking slider, slidably disposed in the accommodation chamber of the base, wherein the locking slider is provided with a second arc surface disposed opposite to the first arc surface, and a side of the locking slider is provided with a first rack; a first elastic member; and an elastic slider, slidably disposed in the accommodation chamber of the base, wherein one end of the elastic slider is provided with a second rack, wherein the second rack is meshable with the first rack. Accordingly, the chair chassis according to the embodiments of the present disclosure achieves reclination memory adjustment of a backrest of the chair.

An electrically controlled chassis includes: a chassis body; an electrical control box, internally provided with an accommodation space; a drive motor, configured to control lift adjustment of the chassis of the chair and pitch adjustment of a backrest of the chair; a winding mechanism, connected to an output shaft of the drive motor; a first pull cord, reversely wound on the winding mechanism; a second pull cord, normally wound on the winding mechanism; a backrest adjustment mechanism, disposed on the chassis body, and fixedly connected to the other end of the first pull cord; and a chassis lift mechanism, disposed on the chassis body, and fixedly connected to the other end of the second pull cord.

A chair includes a base and a back coupled to the base. The back includes a pair of back supports extending from the base and a back panel coupled to the pair of back supports. Each back support is configured to exhibit a first bending stiffness when bent to a first stop point, and exhibit a second bending stiffness when bent beyond the first stop point, the second bending stiffness being greater than the first bending stiffness.

A backrest includes a primary frame having a pair of laterally spaced first uprights defining a first opening therebetween, a first front surface and a first rear surface. A secondary frame includes a pair of laterally spaced second uprights defining a second opening therebetween, a second rear surface facing the first front surface of the primary frame and a second front surface, wherein the secondary frame is coupled to the primary frame, and wherein at least portions of the first and second openings are aligned. A flexible shell overlies and is coupled to the second front surface of the secondary frame. The flexible shell includes a third rear surface visible through the aligned portions of the first and second openings.

A backrest includes a primary frame having a pair of laterally spaced first uprights defining a first opening therebetween, a first front surface and a first rear surface. A secondary frame includes a pair of laterally spaced second uprights defining a second opening therebetween, a second rear surface facing the first front surface of the primary frame and a second front surface, wherein the secondary frame is coupled to the primary frame, and wherein at least portions of the first and second openings are aligned. A flexible shell overlies and is coupled to the second front surface of the secondary frame. The flexible shell includes a third rear surface visible through the aligned portions of the first and second openings.

A chair that provides movement side-to-side about a first pivot axis positioned above the seat plane allows the user a wide range of dynamic movement, but does not require constant or excessive action on the part of the user to maintain a desired position. In addition and concurrently thereto, the chair may include structures that allow the seat to be easily positioned and adjusted side-to-side from a neutral position along a defined pivot axis above a seat plane, and it may, if desired, also provide forward-and-back movement of the seat about a second pivot located above or below the seat plane, an improved seatback that supports the user's back without limiting the user's ability to move their shoulder blades, an improved biasing structure for biasing the seat to a neutral position, an imbedded controller or imbedded sensor for allowing the seat's position to be used as a computer controller, or the gathering of the users motion data, and an adjustable tilt locking system to allow the forward-and-back movement of the seat to be held in a desired position.

A home or office chair is disclosed having a flexible mesh back rest and a full lumbar back support including upper and lower lumbar supports that are located one above the other at the back of the chair to press against the outside of the mesh back rest. The upper and lower lumbar supports are connected to the back of the chair by a bolt so as to move back and forth in first and opposite directions in response to a user seated in the chair moving his back against and away from the flexible mesh back rest. The upper and lower lumbar supports of the full lumbar back support apply continuous pressure through the mesh back rest to provide support for upper and lower lumbar areas of the user's back regardless of whether the user's back is at rest or pressing against the mesh back rest.