TRAVELING CRANE

• Main Authors: LONG, HERBERT D., JR, REUSS, ROBERT H
• Format: Patent
• Language: English; French
• Published: 03.12.1996
• Edition: 6
• Subjects: CRANES; HAULING; HOISTING; LIFTING; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS,WINCHES, OR TACKLES; PERFORMING OPERATIONS; TRANSPORTING

A gantry crane travelable along a pair of rails and having an overhead girder transverse to the direction of travel, first and second legs connected to the girder, a load carrying trolley movable along the girder to a first position adjacent the first leg and to a second position adjacent the second leg, first and second spaced apart motor drives mounted on one of the legs in engagement with one of the rails for moving the crane, and third and fourth spaced apart motor drives mounted on the other leg in engagement with the other rail for moving the crane. When the trolley is at the first position, the first and second drives are highly loaded and the third and fourth drives are lightly loaded. Thereby, the lightly loaded drives attempt to drive the second leg such that it leads the first leg and skews the crane. When the trolley is at the second position, the third and fourth drives are highly loaded and the first and second motor drives are lightly loaded. Consequently, the lightly loaded drives attempt to drive the first leg such that it leads the second leg and skews the crane. A power source is connected to the first and third drives and a power source is connected to the second and fourth drives. The power sources are responsive to the presence of the trolley at either its first or second position to provide a large portion of their electrical power to the highly loaded motor drives to prevent skew.