GB1340978A - Telescopic crane jib - Google Patents

Abstract

1340978 Bolt fastenings LEO GOTTWALD KG 9 Feb 1972 [13 Feb 1971] 6092/72 Heading E2A [Also in Division B8] A crane jib comprises a housing 1 and three telescopic parts 2, 3, 4 and has short peak outriggers 5, 6. A single acting hydraulic cylinder 8 is fixed rigidly at its bottom to the lowest telescopic part 2. Piston rod 7 of the cylinder 8 is fixed at its lower end to the bottom of the housing 1. The parts 2, 3, 4 are all of the same length which is less than half the length of the housing 1. For extension the jib is brought to the vertical position by a head-stay cable 25 and locked there by a telescopic rod 26. Liquid is exhausted from the cylinder 8 so that the parts 2, 3, 4 all move downwards leaving the peak outriggers 5, 6 suspended from the upper end of the housing 1. When the parts 2, 3, 4 reach their lower limit outrigger foot 15 is locked to the upper end of part 4. The piston 7 is now extended from the cylinder 8 lifting the parts 2, 3, 4 and the outriggers 5, 6 until upper rim 16 of the part 4 moves past spring-loaded catches 17 at the upper edge of the housing 1, whereupon retracting the piston 7 and cylinder 8 leaves the part 4 suspended while the parts 2, 3 descend to the position shown in Fig. 4b. The lower end of part 4 is then locked to the upper end of part 3 and by similar cycles of extension and retraction, the parts 2 and 3 may also be extended, all the parts 2, 3, 4 being locked together end to end. The jib may also be only partly extended in various ways as desired, suitable locking devices being provided. Fig. 8 shows a two-stage locking device for locking the lower end of part 4 to the upper end of part 3. A tube 20 fixed to the lower end of part 4 contains a bolt 18 and a tube 30 fixed to the upper end of part 3 contains a bolt 19. A limit stop 31 is also fixed to the upper end of part 3. At the end of the movement when part 3 is being lowered into the housing 1 the stop 31 comes to rest on the tube 20 whereupon the bolt 18 is advanced pneumatically to the position shown. Subsequently, when part 3 is raised a supporting surface 32 (which may be the inner surfaces of the tube. 30) supports the bolt 18 whereupon the bolt 19 can be advanced pneumatically into a bore 34 of the bolt 18 with a wedging action. Fig. 10 shows how the bolt 18 at the lower end of part 3 wedgingly engages a sleeve 35 at the lower end of part 2 to lock these lower end parts together. Fig. 11 shows the parts 3 and 4 locked together at their upper ends by a nose 39 on the bolt 19 engaging an opening 37 in part 4. The nose 39 is forced into contact with wedge 38 by a pin 40 actuated by a wedge 42 advanced by an hydraulic cylinder 41. Fig. 11a shows a further locking device using two bolts 47, 48. A nose 50 of the boit 47 engages a wedge 52 in an opening 51, a piston 49 advancing bolt 48 to thrust the nose 50 firmly into engagement with the wedge 52.