Abstract: A wheelchair frame for flexing to accommodate irregularities in the ground consists of a generally rectangular structure having side rails joined by front and rear cross members. One of the cross members is rigid, and receives the side rails through apertures which permit rotation of the side rails within the cross member. The second cross member consists of a tube in tube arrangement or other such means for permitting rotation of the cross member relative to the side rails. The rigid cross member may be slidably displaced along the side rails for changing the wheelbase of the wheelchair. A wheelchair seat frame may be mounted to the rectangular frame by means of fore and aft struts which permit movement of the seat frame relative to the lower rectangular frame to accommodate flex of the lower frame, while also providing a tilt function for the seat frame.

Abstract: A wheelchair frame for flexing to accommodate irregularities in the ground consists of a generally rectangular structure having side rails joined by front and rear cross members. One of the cross members is rigid, and receives the side rails through apertures which permit rotation of the side rails within the cross member. The second cross member consists of a tube in tube arrangement or other such coupling for permitting rotation of the cross member relative to the side rails. The rigid cross member may be slidably displaced along the side rails for changing the wheelbase of the wheelchair. A wheelchair seat from may be mounted to the rectangular frame by means of fore and aft struts which permit movement of the seat frame relative to the lower rectangular frame to accommodate flex of the lower frame, while also providing a tilt function for the seat frame.

Abstract: A tilting and laterally folding wheelchair design is described in which a tilting mechanism incorporating a pivoting action at both the front and back of the chair is provided so that as the chair is tilted the center of gravity of the occupant is maintained relative to the wheelbase. A lateral folding device, which incorporates X-cross members free at their upper ends, is stabilized by link members which are pivotally mounted at their outer ends, so as to provide room for the chair to be folded laterally.