Foldable tiltable wheelchair and frame therefor

A foldable tiltable wheelchair comprising:

• a base frame comprising first and second side frames;
• at least a first hinged foldable cross-member connecting the side frames;
• a seat frame supported for pivotal movement in relation to a forward portion of the base frame so that the seat frame is tiltable in relation to the base frame, the seat frame having first and second seat rails;
• first and second locking gas springs operatively connected between the first and second side frames and the first and second seat rails, respectively
• wherein the locking gas springs are operatively connected between the side frames and the seat rails by linkage arrangements comprising:
• first and second fulcrums connected to an end of the first and second locking gas springs, respectively, each of the first and second fulcrums pivots about a medially positioned pivot, and
• first and second linkages connecting the first and second fulcrums to the first and second seat rails, respectively, and wherein
• as the locking gas springs extend, the fulcrums pivot about the medially positioned pivots to drive the linkages to raise the seat frame.

A foldable tiltable wheelchair comprising:

• a base frame comprising first and second side frames each having a front end;
• wheels supported in relation to the base frame for supporting the base frame for movement in relation to a supporting surface;
• a seat frame comprising first and second seat rails supporting a seat, the first and second seat rails that provide a structure for supporting a seat, the first and second seat rails each having a front end connected for pivotal movement to the front end of the first and second side frames, respectively, so that the seat frame is tiltable in relation to the side frames while minimizing rise in a user's knee level;
• and
• a first hinged foldable cross-member connecting the side frames, the first hinged foldable cross-member comprising first and second portions each having a first end connected for pivotal movement to the first and second side frames, respectively, and being movable in a forward direction and a rearward direction of the wheelchair;
• a second hinged foldable cross-member connecting the seat rails, the second hinged foldable cross-member comprising first and second portions each having a first end connected for pivotal movement to the first and second seat rails, respectively, and being movable in a forward and rearward direction of the wheelchair;
• first and second locking gas springs operatively connected between the first and second side frames and the first and second seat rails, respectively, the first and second locking gas springs providing lateral support for the first and second seat rails in relation to the first and second side frames, respectively, the first and second locking gas springs further providing vertical support to the seat frame in relation to the base frame, and
• lateral support structure constraining the first and second seat rails against lateral movement in relation to the first and second side frames, respectively.

A foldable tiltable wheelchair comprising:

• a base frame comprising first and second side frames;
• a seat frame supporting a seat and supported for pivotal movement in relation to a forward portion of the side frames so that the seat frame is tiltable in relation to the side frames, the seat frame having first and second seat rails;
• and
• a first hinged foldable cross-member (22) connecting the side frames;
• a second hinged foldable cross-member (24) connecting the seat rails;
• first and second locking gas springs operatively connected between the first and second side frames and the first and second seat rails, respectively, and
• lateral support structure (92) constraining the first and second seat rails against lateral movement in relation to the first and second side frames, respectively, wherein the locking gas springs are operatively connected between the side frames and the seat rails by linkage arrangements comprising:
• first and second fulcrums connected to an end of the first and second locking gas spring, respectively, each of the first and second fulcrums pivots about a medially positioned pivot, and
• first and second linkages connecting the first and second fulcrums to the first and second seat rails, respectively, and wherein
• as the locking gas springs extend, the fulcrums pivot about the medially positioned pivots to drive the linkages to raise the seat frame.

A foldable tiltable wheelchair comprising:

• a base frame comprising first and second side frames each having a front end;
• wheels supported in relation to the base frame for supporting the base frame for movement in relation to a supporting surface;
• a seat frame comprising first and second seat rails that provide a structure for supporting a seat, the first and second seat rails each having a front end connected for pivotal movement to the front end of the first and second side frames, respectively, so that the seat frame is tiltable in relation to the side frames while minimizing rise in a user's knee level;
• and
• a first hinged foldable cross-member hingedly connecting the side frames, the first hinged foldable cross-member comprising first and second portions each having a first end connected for pivotal movement to the first and second side frames respectively, and being movable in a forward direction and a rearward direction of the wheelchair;
• a second hinged foldable cross-member hingedly connecting the seat rails, the second hinged foldable cross-member comprising first and second portions each having a first end connected for pivotal movement to the first and second seat rails, respectively, and being movable in a forward and rearward direction of the wheelchair;
• at least a first locking gas spring operatively connected between the first side frame and the first seat rail, the first locking gas spring further providing vertical support to the seat frame in relation to the base frame;
• and
• lateral support structure constraining at least one of the first and second seat rails against lateral movement in relation to at least one of the first and second side frames, respectively.