GB596544A - Improvements in bridge cranes - Google Patents

Abstract

596,544. Bridge cranes; hoists. - BURGESS, A. F. (Harnischfeger Corporation). July 30, 1945, No. 19446. [Classes 78(iii) and 78(iv)] In a bridge.crane, particularly for use on ships, each of the runways for the gantry is provided with a section which is vertically movable to and from the level of the runways, means being provided to move both sections simultaneously. In the embodiment shown in which the crane is mounted on a boat 1, Fig. 1, each runway for the gantry 15, Fig. 2, comprises members 7, 8 permanently supported on columns 2, 3; 4, 5 and connected by a girder 10, Fig. 4, and a section 19 which is movable vertically along guide ribs 20 on the columns 3, 4. The section 19 is raised to the position shown in Fig. 1 by the cables 24, 25 of the hoisting trolleys 22, 23. These. cables are passed through blocks 26, 28, 30 and 27, 29, 31, Fig. 5, respectively and anchored at 32 on the deck. The blocks , 30, 31 each engage a tackle for lifting one of the sections 19. The tackle engaged by the block 30 comprises cables 33, 34 passing over blocks 37, 38, 39 and 40, 41, 42, 43 respectively and anchored to the blocks 39, 43, the blocks 38, 42 being mounted on the members 7, 8 and the blocks 39, 43 on one of the sections 19. In a similar way the block 31 is connected to blocks 47, 50 on the other section 19. When these sections are raised to their upper position, their lugs 52, Fig. 4, engage in recesses in members 51 secured to the runway members 7, 8 and the sections are held by nuts threaded on screws 53 projecting through the members 51. In their lower position the sections 19 rest on ledges 54. When the gantry is lowered on the sections .19, the parts 56a, 56b of the operator's platform 56 are swung vertically about pivots 56c, 56d to the dotted line positions shown in Fig. 2. Separate winches may be. provided for raising the sections 19 instead of utilising those of the trolleys 22, 23. Alternatively screw or hydraulic lifting gear may be provided. Racks on the runways engaged by gears on the gantry ensure positive control of the gantry when listing of the ship occurs.