Method of construction for a composite wheelchair chassis

Abstract

A generally hollow or foam filled, light-weight wheelchair chassis is constructed from composite materials preferably by compression molding using sheet molding compound for volume production, or by resin transfer molding for the production of smaller numbers of units. Each chassis side may be formed in one or two side portions Two-portion side construction is preferred for compression, and the portions may be molded as a left segment and a right segment that are joined vertically, or as an upper segment and a lower segment that are joined horizontally. Joining may be by conventional pin and socket devices, lap joints, or tongue and groove joints. Manufacture by resin transfer molding is preferred when each chassis side is to be made in one-piece. Metallic elements may be placed into the molds prior to curing, or bonded to the chassis following curing. Reinforcing ribs may also be integrally formed with the sides, or separately formed and attached by suitable bonding or attachment techniques. The chassis sides may also be manufactured in one piece from composite materials using reinforced reaction injection molding, structured reaction injection molding, hand layup over foam techniques, and hand layup with internal pressure techniques. The manufactured composite chassis preferably has two longitudinal sides, one or more cross-bars between the sides, and two self-supporting torsion arms extending forwardly and downwardly from the chassis sides and terminating in sleeves for holding casters.