Equalization system for overhead cranes

An overhead crane comprising a rigid generally rectangular bridge frame, a truck beneath each corner of the frame for supporting the latter on parallel rails of a main runway for longitudinal movement, a trolley carrying hoisting machinery and movable laterally of the rectangular frame, oppositely acting levers forming the connections between the trucks on one side only of the frame and the frame itself, and a link interconnecting the levers independently of the frame to equalize the loads on the trucks so connected, the levers each having a generally vertically extending lever arm and horizontally spaced longitudinally inner and outer trunnions forming a second longitudinally extending lever arm at the base of said vertically extending lever arm, the bridge frame being supported by the longitudinally outer trunnions of the two levers, and the trucks supporting the longitudinally inner trunnions of the two levers, the top ends of the vertically extending lever arms being connected by a link extending between the arms, the vertical extent of each vertically extending lever arm being very large compared to the horizontal extent of the longitudinally extending lever arms formed by the spacing of the axes of the trunnions.