Abstract: A wheelchair chassis may include a first and second side frame positioned substantially parallel to and at a width apart from one another. The chassis may also include a first and second receiver tube positioned substantially parallel to and coupled to the first and second side frames, respectively. The chassis may additionally include a first and second extension tube telescopically engaged with the first and second receiver tubes, respectively. The chassis may further include a first and second cross member, with the first cross member pivotally coupled to the first receiver tube and the second extension tube and the second cross member pivotally coupled to the second receiver tube and the first extension tube. The second cross member may be engaged to the first cross member in an X-shaped configuration disposed horizontally between the side frames, where the second cross member is substantially co-planar with the first cross member.

Abstract: A frame support apparatus and coupling device for use with an ambulatory system and method of fabrication thereof. In one embodiment an ambulatory system having a frame support is provided. The ambulatory system includes a first side frame having a front portion and a rear portion, a second side frame having a front portion and a rear portion and a frame support coupled between the first side frame and the second side frame. The frame support includes a first cross-member having a first end and a second end, the first end pivotably coupled to a coupler. The system further includes a second cross-member having a first end and a second end, the first end of the second cross-member coupled to the coupler. Wherein the first end of the second cross-member is maintained in a substantially fixed position relative to the coupler.

Abstract: A multi-wheeled vehicle having adjustable wheelbase dimensions. The preferred embodiment is a wheelchair which affords on-the-fly adjustment of width. The linkage between the two side frames of the present wheelchair is of two cross members in a horizontal X configuration, one end of each cross member being pivotally affixed to one side frame on one side of the wheelchair, with the respective other end of each cross member being slidably engaged with the opposite side frame. The cross members are pivotally attached to each other at a point of intersection. This structure allows a wheelchair of the present design to be easily expanded and contracted in width during use, with the rider in-place, and avoids the necessity of incremental changes between uses, such as is required by wheelchairs of present design. Yet, such a wheelchair is structurally quite stable with respect to any tendency of the side frames to toe-in under torque applied by weight on the seat.

Abstract: An improved multi-wheeled vehicle having adjustable wheelbase dimensions. The preferred embodiment is a wheelchair which is adjustable as to length and width "on-the-fly." Contracting the two side frames effects a simultaneous retraction of the forward wheel struts. Thus, the length of the wheelchair is reduced at the same time the width is reduced, and vice versa. The linkage between the two side frames is preferably two cross members in an X configuration, one end of each cross member being pivotally affixed to one side frame on one side of the wheelchair, with the respective other end of each cross member being pivotally affixed to a wheel strut on the opposite side of the chair, the two wheel struts each being slidably attached to respective side frame.