In large-capacity bridge girder erection machine, the magnification of the pulley unit is quite large. For example, it reaches 10 in a 200-ton crane and 12 in a 250-ton bridge. At the same time, it is selected. The rope may wish to withstand a load of 11 tons.
In order to reduce the pulley ratio of the bridge girder erection machine, different trolley structures were selected. This structure is basically designed with new strong ropes. The wire rope has a diameter of 44 cm and a support strength of 27 tons.
When this type of rope is used in a bridge girder erection machine, it may be necessary to ensure a significant reduction in the weight and manufacturing effort of the trolley due to the reduced number of parts used. Unique is that the bridge crane with large lifting capacity has a higher lifting height. The reduction in weight and manufacturing effort is even more significant.
Not only that, the number of parts for the suspension and lifting mechanism of the bridge girder erection machine was reduced from 997 to 362; the steel structure part of the trolley frame was reduced from 69 to 19; the wheelbase of the trolley was reduced from 136000px to 108500px. . For 250-ton trolleys, the total number of parts required for processing has been reduced from 716 to 582.
While reducing the magnification of the pulley block, the bridge girder erection machine can also choose to use a reduced suspension with a mandrel support beam. As a result, the height of the building may be reduced under the same lifting height, and the lifting height may be increased in the building under the same conditions.
Therefore, when designing a trolley for a bridge girder erection machine, an organization structure and a hanging hook suspension device are usually used to make the distance between the center of the fully loaded trolley and the wheel equal to meet different lifting requirements.
