An improved portal crane capable of travelling round curves

摘要

776,475. Motor vehicle driving gear. MASCHINENFABRIK AUGSBURG-NURNBERG AKT.-GES. Jan. 13, 1955 [Jan. 23, 1954], No. 1110/55. Class 79(2). [Also in Group XXX] The gantry 2 of a portal crane is pivoted at 1, 1a, to the supporting columns 3, 4 and relative motion about the pivots controls the driving motors to establish the proper difference of speed between the two columns when the crane is negotiating curves. In the form illustrated an auxiliary motor 11 assists the normal motor 10 driving the column 3 on the outside of the curve and is controlled by resist ance varied by arms 8, 8a on the gantry operated by projections 9, 9a on the column 3. The motors 10, 11 are three-phase slip-ring motors and the controlling resistors are inserted in the armature circuit of the motor 11. Where the track curves in opposite directions the motor 11 may be reversed to oppose the torque of the motor 10 or a second auxiliary motor (11), controlled by devices on the column 4 may assist the motor 10 driving that column. A single transmission gear 12 provides different transmission ratios for the motors 10 and 11. The motor 11 may be brought into operation by a manual control or automatically by abutments on the track.