Patent GB-662345-A (GB)
Title: Control device for the dredge-tube suspension cables of a suction dredger
IPC: E02F3/90
Filed: 1949-02-04
Abstract: 662,345. Dredgers. ATELIERS ET CHANTIERS DE BRETAGNE, ANCIENS ETABLISSEMENTS DE LA BROSSE ET FOUCHE. Feb. 4, 1949 [Dec. 16, 1948], No. 3193/49. Class 113 (ii). In a control device for the dredge tube of a suction dredger having davits arranged along the side throughout the length of the dredge tube from which davits the latter is suspended at a number of points through winch operated cables, one reach of each cable is fastened to a fixed point, the other reach only being controlled by the hoisting winch. The dredge tube, comprising a connecting knee 3, a suction nose 11, and sections 6, 8, 10 connected together by a flexible joint 7 and a swivel joint 9, is suspended from davits 12, 13, 14, 15, at the knee 3, the joints 7 and 9, and the nose 11 respectively. The davits are of the type described in Specification 657,181, and in each case the lower reach of the hoisting cable is attached to a drum 22, Fig. 7, having a worm gear meshing with a worm 24. For the hoisting cables for the parts other than the nose 11, the shaft of the worm 24 terminates in a crank which makes it possible to make allowance manually for the lengthening of the corresponding cable. As shown in Fig. 7, the shaft of the worm for the suction nose cable is controlled from a motor 26 which serves on the one hand to take up the elongation of the cable and, on the other hand, to slacken out said cable after the tube has been lowered in order to allow the nose to be given the necessary fredom for it to remain applied against the bottom during the up-anddown motion of the dredger due to the swell, in this case the upper reach of the cable being taken round a sheave 30 which moves vertically in slide-blocks and from which a counter balance weight 31 is suspended. All the upper reaches of the hoisting cables are connected to a common winch 35 comprising a shaft in two sections 40 and 41 adapted to be rigidly connected together through a clutch 42, and a shaft 43, the shafts being connected through equal gears 44 in mesh with a pinion 45 driven from a motor 47. The shaft 41. carries a drum 48 for the knee hoisting cable; the shaft 43 carries two drums, the one 50 for the flexible joint hoist cable, and the other 51, for the swivel hoist cable; and the shaft 40 carries a drum 49 for the nose hoisting cable. The drums 48 and 50 are of equal diameter and the drums 49 and 51 have winding sections 52 equal in diameter to the first mentioned drums and sections 53 of larger diameter, said sections of different diameter in a common drum being connected by a groove 54. The diameter of the drum 50 and the sections 52 of the drums 51 and 49 are proportional to the distances of the flexible joint 7, the swivel joint 9, and the nose 11 respectively from the knee 3. The clutch 42 contains a spring which urges it out of engagement. The shaft 40 is hollow and houses a rod, one end of which is adapted to move the clutch 42 into engagement against the action of its spring, the other end being connected through levers to a finger which projects through the groove 54 in the drum 49. At the commencement of the tube raising operation the clutch 42 is dis-engaged and the drum 48 stationary. The drums 50 and the sections 53 of the drums 51 and 49 hoist their respective cables to raise the tube to a horizontal position, at which instant the cable on the drum 49 engages the groove 54 and depresses the finger, thereby moving the clutch 42 into engagement and rotating the drum 48. The cable on drums 41 and 51 moves on to the sections 52 so that all four drums 48, 49, 50, 51 raise the tube in unison up on to the deck, keeping it horizontal.