Abstract: A wheelchair lift assembly having first and second attachment arm assemblies (26a and 26b) is disclosed. The first and second attachment arm assemblies extend between a reciprocating platform (24) and a lift platform (28). The lift platform is movable between at least a raised position and a lowered position. The lift platform being held in a substantially horizontal first plane as the lift platform is moved between at least the raised and lowered positions. A support device (20) coupled to one of the first and second attachment arm assemblies for supporting one of the first and second attachment arm assemblies and maintaining the lift platform in a second plane substantially parallel to the first plane if at least a portion of the other of the first and second attachment arm assemblies fail.