GB638628A - Improvements relating to ships' gears for the loading and unloading of cargo - Google Patents

Abstract

638,628. Ship's derricks. SLATER, A. Sept. 9, 1946, No. 27035. Convention date, Sept. 11, 1945. [Class 78 (iv)] A derrick, Fig. 1, for loading and unloading a ship's cargo includes a mast 9a; a pair of coactive derricks 4, 7 pivotally associated with the mast ; a cargo hoisting gear 79 associated with each derrick ; power-actuated topping gear connected to each derrick to adjust the inclination thereof and comprising a cable 11 anchored to the outer end 12 of the derrick and extending through a bight span 15 to an anchorage point 16 on the mast ; a pair of flexible extensions connected to the bight span pulley 15 one of which extensions comprises a cable 18 leading to a winch 22, and mechanical locking means 28 engageable with the other flexible extension to maintain the derrick in the adjusted working inclination. Topping gear. Cable 11 is attached to the end of the derrick (e.g. 4), passes round pulley 13 on the mast 9a, passes down and round pulley 15 and is secured at 16 on the mast. The derrick is luffed from winch 22 by cable 18 attached to the pulley 15 and is secured in position by chain 27 which is attached to the same pulley and is held by pin 31, Fig. 6. Pin 31 is operated from wheel 107 through pinion 40 and rack 37 and has a longitudinal groove at its end so as to engage and hold the lower link the better. Alternatively the pin and rack may be disposed parallel but out of alignment and connected so that they move together as one. The loose end of the chain falls into a compartment below deck. Slewing gear. The end of each derrick (e.g. 4) is connected to pulley 51 and this is connected by cable 50 to pulley 52, pulley 54 and winch 58. Pulley 52 is secured by cable 60 to a point at the side of the derrick so that winch 58 slews the derrick round. Derrick-connecting gear. Additional means of varying the position of derrick 4 is obtained by means of cable 61 which is attached to the end of derrick 4 passes round pulley 62 on derrick 7 and round pulley 63 and is fixed at 64 on the derrick 7. Winch 66 pulls cable 65 which is secured to pulley 63 and luffs or slews derrick 4. Lifting tackle. Derrick 4 has a lifting hook on the end of cable 79 which is operated by winch 81. It also has lifting hook 77 at the end of cable 70 which passes round pulleys 71 and 72 and is operated by winch 75. Hook 77 is controlled in position by cable 76. Operation. Derrick 4 is secured in position over the hold 49. Derrick 7 is secured in position over the wharf. Hook 77 is lowered into the hold to lift up the cargo which, under the pull of cable 76, is transferred to the two lifting hooks of derricks 4 and 7. The two hooks, under the pull of their respective cables 79 together transfer the cargo towards the wharf, where the hook of derrick 4 is slipped off and the cargo is lowered on the hook of derrick 7.