A medical chair includes a seat supported by a base and actuators adapted to both tilt and lift the seat with respect to the base. A controller controls the actuators to both lift and tilt the seat as the seat moves from the sitting position to the standing position. The movement from the sitting position to the standing position assists in the egress of an occupant from the chair, while the movement from the standing position to the sitting position assists in the ingress of an occupant to the chair. A backrest on the chair remains substantially vertically oriented during movement between the sitting and standing position so as to provide more comfort to the occupant during the sit-to-stand or stand-to-sit movement. The backrest also moves in a manner that generally keeps the occupant's torso vertically aligned with his or her hips during this movement.

A wheelchair including a base assembly that has a first side and a second side. At least one caster and a drive wheel are mounted to each of the first and second sides. The wheelchair includes a seat assembly having a seat and a backrest and an actuator assembly having a plurality of actuators. Each actuator can expand and retract and includes a first end pivotably connected to the base assembly and a second end pivotably connected to the seat assembly. The actuator assembly allows for at least four degrees of movement of the seat assembly with respect to the base assembly. The wheelchair includes a computer that is connected to the actuators and that controls the movement of the actuators. The computer moves the actuators to vary the position of the seat assembly with respect to the base assembly.

This invention provides a wheelchair with four wheel independent suspension and modular seating, allowing for customized seat selection and a variable ride. It includes a chair assembly, a chassis assembly and a suspension assembly. The chair assembly includes a seat; a seat mount; a seat angle adjuster; and a pillar. The chassis assembly includes a chassis; and a handle assembly. The suspension assembly includes a forward suspension assembly and a rear suspension assembly. In another embodiment, the wheelchair includes a chair assembly with handles, a main cross beam and a suspension spring assembly.

The present invention is directed to a tilt-in-space wheelchair that limits the shift of the center of a gravity of a wheelchair occupant during tilting. The wheelchair comprises a main frame adapted to be supported on a surface by wheels, a seat frame for supporting a occupant, and an arc plate for slidably or rollably supporting the seat frame with respect to the main frame. The arc plate defines a first track and a second track that guide the tilting of the seat frame relative to the frame. The first track and second track may have non-constant curvatures. Further, the first track and second track may be arranged non-concentrically on the arc plate and may have different lengths.

A seat positioning system includes a base frame having a pair of forward slots and a pair of rear slots, and a seat frame having a front end and a back end. The seat frame is coupled to the base frame and movable relative to the base frame. A first pair of linkages is slideably coupled to the pair of forward slots and connects the frames. A first pair of locking devices has a locked configuration adapted to prevent the first pair of linkages from sliding relative to the pair of forward slots and an unlocked configuration adapted to allow the first pair of linkages to slide relative to the pair of forward slots. A second pair of linkages slideably is coupled to the pair of rear slots and connects the frames. An actuator is pivotally connected to both the seat frame and the base frame and is configured to extend and contract to move the seat frame relative to the base frame.