A gap-clearing mechanism for attachment to a wheelchair is disclosed. The gap-clearing mechanism has a lower member for attachment to the wheelchair, and an upper member spaced from and parallel to the lower member and being moveable relative thereto. The upper member has at least one support column securely attached thereto and depending therefrom. The at least one support column is slideably mounted relative to the lower member. There is a wheel assembly at a lower end of the at least one support column. The wheel assembly is moveable between a retracted position and an extended position. A wheelchair fitted with two such gap-clearing mechanisms is also disclosed.