A chair has a seat, a backrest, a lift structure, a back supporting structure, and a waist supporting structure. The backrest is deposited behind the seat. The lift structure is deposited on the backrest. The back supporting structure has a bending element and multiple supporting strips. The bending element is connected with the backrest and the lift structure, and is elastic and bendable to deform. The supporting strips are deposited on the bending element at spaced intervals from a top to a bottom of the bending element. The waist supporting structure is deposited in front of the back supporting structure. The waist supporting structure has two pivoting bases and a supporting plate. The pivoting bases are deposited on the seat. The supporting plate is pivoted between the two pivoting bases, abuts the back supporting structure, and selectively abuts the backrest.

The object of the invention is a convertible, dual function chair for sitting and kneeling, which gives the possibility of changing the position and relieving the spinal column during a prolonged work in a sitting position.

The dual function chair for sitting and kneeling is equipped with a movable backrest and headrest support, shaped in the lower part in such a way that its displacement changes the size of the chair simultaneously vertically and horizontally. It is also equipped with a sliding-rotating-returning or a sliding-returning backrest device, which makes it follow the user's back and support it accurately at every angle of inclination of the backrest when tilting the backrest. It is also equipped with a headrest connected to the headrest arm through a rotary-sliding mechanism, which rotationally connects with the backrest support, and has a specially shaped five-star base, in which the arms, apart from the fragment above the wheels, are maximally flattened and located as low as possible above the ground.

A headrest lifting mechanism is revealed. The headrest lifting mechanism is disposed on a seat back and including a lifting base, a bottom-side vertical support and an elastic positioning rod. A headrest is connected to an upper end of the bottom-side vertical support. A positioning end of the elastic positioning rod fixed on the bottom-side vertical support is moved downward into one of the slots of the lifting base owing to material elasticity when the bottom-side vertical support is assembled with the lifting base. Thus the bottom-side vertical support and the positioning end are slid and positioned together in the slots of the lifting base. The number of the parts is reduced and the assembly is simplified. This enables cost reduction and mass production.

A seat back support assembly comprises a vehicle engaging member and a seat back receiving member. The vehicle engaging member is configured to be secured to a vehicle body. The vehicle engaging member includes a supporting section. The seat back receiving member includes (i) a base that is adjustably coupled to the supporting section, and (ii) a receiver that is coupled to the base, the receiver being configured to receive the seat back. The base is alternately positioned in a first vertical position and a second vertical position relative to the supporting section. When the base is in the first vertical position, the seat back is at a first height relative to the vehicle seat. Alternatively, when the base is in the second vertical position, the seat back is at a second height relative to the vehicle seat that is different than the first height.

A method for adjustably supporting a seat back of a vehicle includes securing a vehicle engaging member to the vehicle body, the vehicle engaging member including a supporting section; and adjustably coupling a seat back receiving member to the vehicle engaging member, the seat back receiving member including (i) a base that is adjustably coupled to the supporting section, the base being alternatively positioned in a first vertical position and a second vertical position relative to the supporting section; and (ii) a receiver that is coupled to the base, the receiver being configured to receive the seat back. When the base is in the first vertical position, the seat back is at a first height relative to the vehicle seat. Additionally, when the base is in the second vertical position, the seat back is at a second height relative to the vehicle seat that is different than the first height.

An orthopedic device for improving posture while sitting, having a foundation member including a front portion for upper legs and a bowl portion for lower pelvic area. The bowl portion has a central portion and an upwardly inclined lateral portion. The lateral portion and the front portion collectively surround the central portion. A channel attachment is connected with one or more pelvic crest portions. The channel attachment portion connects over a concave recessed portion. The central portion has plural regions of varying flexibility and the lateral portion has plural regions of varying flexibility.

A chair having a contoured seat cushion mounted on top of an exercise ball with four tension-adjustable elastic cords such as bungee cords is provided. The shock absorbing cords may attach to the underside of the seat cushion by looping through spring-eye carabiner type hooks, and may pass through grooved locking tubes with v-channels for adjusting the cord tension. The ball may sit on top of a swivel plate, so that dynamic motion and counterbalancing are attainable for a variety of ergonomically beneficial seating styles.

An office chair including a chair back assembly that is independently adjustable to adjust the vertical height of the chair back and to provide lumbar support. The chair back assembly includes a flexible back shell that is movable vertically along a back support yoke. The vertical movement of the flexible back shell adjusts the vertical height of the chair back assembly relative to the seat. The chair back assembly further includes a lumbar adjustment mechanism having an adjustment cable connected to a bottom end of the flexible back shell. Operation of the lumbar adjustment mechanism moves the bottom end of the flexible back shell vertically within a pair of spaced lower movement slots. The movement of the bottom end of the flexible back shell increases the amount that the flexible back shell protrudes from the back support yoke, thereby increasing the lumbar support.

A seat assembly for task-oriented seating comprises a seat support and a seat coupled to the seat support. The seat is movable under load, such as from the user's weight and movements, relative to the seat support. The seat has a cushion molded over a supporting armature with multiple bias elements. The seat and seat support are configured to deflect by predetermined amounts at defined locations over an extent of the seat assembly. In this way, the seat assembly provides for a range of comfortable and effective positions for users engaged in different active motions and having different preferences and sizes.

A seat back support assembly comprises a vehicle engaging member and a seat back receiving member. The vehicle engaging member is configured to be secured to a vehicle body. The vehicle engaging member includes a supporting section. The seat back receiving member includes (i) a base that is adjustably coupled to the supporting section, and (ii) a receiver that is coupled to the base, the receiver being configured to receive the seat back. The base is alternately positioned in a first vertical position and a second vertical position relative to the supporting section. When the base is in the first vertical position, the seat back is at a first height relative to the vehicle seat. Alternatively, when the base is in the second vertical position, the seat back is at a second height relative to the vehicle seat that is different than the first height.