US Patent 7413394 Low headroom telescoping bridge crane system

A telescoping bridge crane system arranged to be mounted over a floor of a structure, e.g., a vehicle trailer, and including a pair of enclosed mounting tracks for slidably supporting a runway frame. Trucks are located within the tracks. Each truck includes a hanger. The runway frame also includes two enclosed tracks which are directly supported by the hangers and located beside and parallel to the mounting tracks. A bridge section is mounted between the enclosed tracks of the runway frame by another pair of trucks. The a bridge section supports an extremely low headroom hoist assembly including an actuator, a cable, plural rotatable sheaves and a hook.