Center-of-gravity tilt-in-space wheelchair

A wheelchair comprising:

• a base;
• a plurality of wheels that are adapted to support the base relative to a supporting surface;
• a seat for supporting an occupant;
• one or more tracks supporting the seat, the one or more tracks serving as a rolling or sliding surface that allows the seat to rotate with respect to the base, the one or more tracks having a substantially constant-radius arc with a focal point that is adapted to be substantially coincident with the center of gravity of the wheelchair occupant;
• and
• a motor operatively connected between the base and the seat so that the seat can be rotated about the center of gravity of a wheelchair occupant.

A wheelchair comprising:

• a base;
• front and rear wheels that are adapted to support the base relative to a supporting surface;
• a seat for supporting an occupant;
• and
• one or more tracks supporting the seat, the one or more tracks serving as a rolling or sliding surface that allows the seat to rotate with respect to the base, the one or more tracks having a substantially constant-radius arc with a focal point that is adapted to be substantially coincident with the center of gravity of the wheelchair occupant, wherein the one or more tracks are adjustable fore and aft with respect to the base and the front and rear wheels so that the position of the focal point relative to the front and rear wheels may be changed.

A wheelchair comprising:

• a base;
• a plurality of wheels that are adapted to support the base relative to a supporting surface;
• a seat for supporting an occupant;
• one or more tracks supporting the seat, the one or more tracks serving as a rolling or sliding surface that allows the seat to rotate with respect to the base, the one or more tracks having a substantially constant-radius arc with a focal point that is adapted to be substantially coincident with the center of gravity of the wheelchair occupant;
• and
• one or more protrusions that are adapted to be engaged with one or more recesses in the one or more tracks so that the protrusions enter the recesses to lock the tracks into an angular position and are adapted to be retracted from the recesses so that the seat can be rotated to a different tilt angle relative to the base.

A wheelchair comprising:

• a base;
• a plurality of wheels that are adapted to support the base relative to a supporting surface;
• a seat for supporting an occupant;
• and
• one or more curved tubes supporting the seat, the one or more tubes serving as a rolling or sliding surface that allows the seat to rotate with respect to the base, the one or more tubes having a substantially constant-radius arc with a focal point that is adapted to be substantially coincident with the center of gravity of the wheelchair occupant.

A wheelchair comprising:

• a base;
• a plurality of wheels that are adapted to support the base relative to a supporting surface;
• an adjustable seating system for supporting an occupant, the adjustable seating system including a seat, a backrest, and a footrest assembly, the seat comprising a seat frame that further comprises laterally spaced side tubes and the backrest comprising laterally spaced canes supported relative to the side tubes by couplings, the couplings including an assembly of plates having upper ends operatively attached to one another and lower ends attached to the side tubes so that the lower ends of the plates can move relative to the side tubes while remaining operatively connected to the side tubes;
• and
• one or more tracks supporting the seat assembly, the one or more tracks serving as a rolling or sliding surface that allows the seat to rotate with respect to the base, the one or more tracks having a substantially constant-radius arc with a focal point that is adapted to be substantially coincident with the center of gravity of the wheelchair occupant, the seat, the backrest, and the footrest assembly being adjusted fore and aft with respect to the focal point.

A wheelchair comprising:

• a base;
• a plurality of wheels that are adapted to support the base relative to a supporting surface;
• a seat;
• one or more tracks located between the base and the seat, the one or more tracks having a constant-radius arc supporting the seat for movement in fore and aft directions relative to the base;
• and
• a low friction support supported by one of either the base or the seat, the low friction support comprising low friction elements that mate with the one or more tracks to provide sole support for the one or more tracks.

A wheelchair comprising:

• a base;
• a plurality of wheels that are adapted to support the base relative to a supporting surface;
• a seat;
• one or more tracks having a constant-radius arc supporting the seat for movement relative to the base;
• and
• a low friction support assembly supported by one of either the base or the seat, the support permitting an overall tilt angle range of the seat to be adjusted.

A wheelchair comprising:

• a base;
• a plurality of wheels that are adapted to support the base relative to a supporting surface;
• a seat for supporting an occupant;
• one or more tracks supporting the seat, the one or more tracks having a constant-radius arc with a focal point that is adapted to be coincident with the center of gravity of a wheelchair occupant;
• and
• the wheelchair seat being structured to be adjusted while maintaining the focal point of the constant-radius arc of the one or more tracks coincident with the center of gravity of the wheelchair occupant.

A wheelchair comprising:

• a base;
• a plurality of wheels that are adapted to support the base relative to a supporting surface;
• a seat for supporting an occupant;
• and
• one or more tracks supporting the seat, the one or more tracks serving as a rolling or sliding surface that allows the seat to rotate in fore and aft directions with respect to the base, the one or more tracks having a substantially constant-radius arc with a focal point that is adapted to be substantially coincident with the center of gravity of the wheelchair occupant.

A wheelchair comprising:

• a base;
• a plurality of wheels that are adapted to support the base relative to a supporting surface;
• a seat;
• one or more tracks having a substantially constant-radius arc having a focal point, the constant-radius arc supporting the seat for tilt movement in fore and aft directions relative to the base over a range of tilt angles;
• and
• a low friction support assembly supported by one of either the base or the seat, the support assembly being adjustable to permit the range of tilt angles to be rotated relative to the focal point.

A wheelchair comprising:

• a base;
• a plurality of wheels adapted to support the base;
• a seat for supporting an occupant;
• one or more arcuate tracks supporting the seat and operatively associated with the seat to permit rotation of the seat relative to the base;
• and
• the seat being horizontally adjustable to permit fore and aft positioning of the occupant's center of gravity relative to the one or more arcuate tracks.