GB1359795A - Jib truck and pulley arrangement for cranes - Google Patents

Abstract

1359795 Truck and pulley arrangements for jib cranes POTAIN 26 July 1972 [26 July 1971] 35103/72 Heading B8B A jib truck and pulley-block arrangement comprises a front truck 5 and a rear truck 4 running on jib track 3. A rear lower pulleyblock 6 is suspended from the rear truck 4 and a front lower pulley-block 7 is suspended from the front truck 5. The front truck 5 is attached at 28 to a truck cable 29 and, with the two trucks 4, 5 latched together as shown they move as a unit. A load cable 8 passes from the rear of the jib over, in succession, front pulley 9 on truck 4, pulley 10 on pulley-block 6, rear pulley 11 on truck 4, front pulley 12 on truck 5, pulleys 13, 14 on pulley-block 7 and rear pulley 15 on truck 5 to be secured to the head of the jib (not shown). A load hook 36 is suspended on a lever 33 pivoted at 34 on the pulley-block 7 and shown hooked on to the block 6 at 39. In this arrangement there is a double tackle between the jib and the load hook 36. The trucks 4, 5 may be separated and the truck 4 latched to the jib adjacent its rear end, (Fig. 1, not shown), with the lever 33 disengaged from the pulley-block 6, Fig. 6 (not shown), this arrangement providing a single tackle between jib and load hook 36. The coupling and uncoupling of the trucks 4, 5 is arranged to be carried out by use of the load cable 8 after the trucks have been correctly positioned by the cable 29. Loads of great length may be handled in a modification illustrated in Fig. 8 (not shown) wherein the trucks 4, 5 are spaced by crosspieces (48), a lifting hook (46) on pulley block 6 and the lifting hook 36 on pulley block 7 being interconnected by a swing-bar (49).