GB256660A - Improvements in or relating to derrick or similar lifting and lowering apparatus - Google Patents

Abstract

256,660. Burditt, T. H. F. March 25, 1925. Jib cranes; vehicle fittings.- A collapsable crane comprising a rotatable pillar fitted with a luffing jib, struts, tackle, and winding gear, is adapted to be carried upon a lorry when collapsed and means are provided for completely dismounting it from the lorry and erecting it upon the ground. The crane, which is shown in Fig. 2, in course of dismounting from the lorry, comprises the pillar 13, jib 14, struts 15, 15a, anchoring boom 17, and winding gear W. The pillar 13 is mounted in a footstep 18 to which are connected the lower en.ds of struts 15, which support a sleeve 16 in which the pillar can turn but not slide. The archoring boom 17 terminates in sectors 20 and is pivoted to the footstep 18 at 19<a>. Separate sector-shaped members 21 are also pivoted at 19a and can be locked to the boom 17 by pins 22 so as to form an extension of the sector 20. During transport the pillar 13 rests upon a roller 12 on the lorry with the boom 17 folded to lie parallel with the struts 15 and with the sector 21 free of the pin 2. For dismounting the crane from the lorry and erecting it, the pillar is moved towards the rear of the lorry and the boom 17 and sectors 21 are brought to the position shown in Fig. 2 by hauling on the rope 27 by means of a winch 26 mounted on the struts 15. During this movement the struts 15a rest upon projections on the boom 17 and are raised as shown. The sectors 21 are now locked to the boom 17 with their ends 25 resting on the ground, and the pillar 13 is raised to the vertical position by gear on the crane hauling on ropes 28 anchored to the ground, movement being controlled by a guy rope 29. The struts 15a are then anchored to the ground and the sectors 21 secured in the position shown in Fig. 4. The jib is provided with a pair of headsheaves A and with a sheave 45 for an additional load rope. this sheave being movable along the jib by racking gear driven by a pulley 33. Four winding drums 39 for hoisting, luffing, and for driving the racking pulley 33 are mounted on opposite sides of the pillar 13, and slueing is effected by motor-driven worm gearing 43, 44, Fig. 7. The winding drums may also be driven by hand-gear at 54. A balance-weight 32 for the jib 14 is carried in or on the pillar 13, opposite ends of the weight being connected with ropes wound oppositely on the luffing drum. The luting rope is connected to the top of the weight and is attached to the jib at 46. The winding drums 39 are driven from a motor 18a carried beneath the foot-plate 31, through gearing 18<b>, 18' and 35, 36, and the two countershafts 37 which provide forward and reverse drives respectively.