GB1187012A - Improvements in Derrick Cranes and Swinging Derricks. - Google Patents

Abstract

1,187,012. Ships' derricks. BPEEDCRANEB Ltd. 20 April, 1967 [19 March, 1966], No. 12216/66. Heading B8B.. A jib 2, Figs. 1, 2, pivoted on a pintle at or near the foot of a mast 1 is topped by a wire D which is led from a topping winch A over pulley sheeves 3, 4 and 5 to a delta plate 6. Two wires F pass from the delta plate 6, each of which is secured to the jib 2 at 9 having passed over a pulley sheave 7 attached to the jib 2 and over a pulley sheave 8. Slueing wires E from a slueing winch B pass around slueing blocks 10 and are secured to the pulley sheaves 8. Balance means comprising the pulley 4 connected to the jib 2 and the delta plate 6 interconnect the topping wire D and the slueing wires E to ensure that a topping force exerted by the wire D is not exceeded by the resultant force in the slueing wires E, and that a slueing force in the wires E is not exceeded by the resultant force in the topping wire D. Fig. 3 shows an alternative rigging for slueing and topping, while Fig. 4g shows a'construction in which the pulley 4 attached to the jib 2 is replaced by rigid members secured to the jib 2 and to the slueing rigging E.