Abstract: A simple, durable, lightweight, economical wheelchair is disclosed that offers full convertibility from rigid frame to folding and vice versa, without sacrificing advantages of either design. In addition, it allows conversion to sports, companion, pediatric, front wheel drive, etc. as well as customizing to suit the end user's needs.

Abstract: A method of constructing a wheelchair that is durable, lightweight, economical and fully adaptable to any end user's requirements, such as sizing, convertibility, environment and lifestyle, and the resulting wheelchair, is disclosed, made possible by the utilization of specially designed weld-free connector fittings with any desirable or available tubular materials.

Abstract: A failsafe weld-free method of joining tubular elements provides for connecting a first tubular element to a second tubular element. The assembly includes an insert, with screw threads, inside of the first tube, a connector fitting for mounting to the insert within the first tube by a screw, a second tube is secured to the connector fitting with a fastener through a transverse hole through both the second tube and the connector fitting. When the connector fitting is assembled to the first tubular section and the connecting screw is tightened, a structurally rigid connection is achieved. The second tubular section is positioned over the stepped outside diameter of the connector fitting, aligning the transverse holes. A fastener is installed through the transverse hole. The fastener that secures the connector fitting to the second tubular section is positioned to not allow the screw fastening the connector fitting to the first tubular section to disengage or loosen.

Abstract: A wheelchair assembly which can be quickly and inexpensively assembled and disassembled is described which is formed of tubular members which are secured only with clamping members to produce a rigid frame wheelchair. No welds are utilized, the clamps being formed of molded composite material, such as a carbon fiber-filled polyamide. Each clamp is formed of complimentary shells formed with semi-cylindrical regions dimensioned to receive, between two mating complimentary members, cross tubes to be secured in pressure fit relationship.