Patent GB-480056-A (GB)
IPC: B66C23/60
Abstract: 480,056. Cranes ; winches. SYLVEN, G. March 12, 1937, No. 7362. [Classes 78 (iv) and 78 (v)] In apparatus of the kind in which a loading boom is connected pivotally to a mast, and a trolley carrying the load is displaceable along the boom, the trolley is traversed by means of a rope attached to a drum and the boom is braced to the mast by a second rope attached to the trolley and to a second drum either on the same shaft as the first drum or geared thereto in such manner that as the trolley moves inwards towards the mast, the bracing rope is coiled at a continually decreasing rate until it becomes perpendicular to the boom and inwards beyond this point is coiled at a continually increasing rate. By this arrangement the load can be moved horizontally between the lines of loading and dumping with a minimum luffing movement of the boom. Fig. 1 shows one arrangement in which a trolley 103 supporting the load 104 slides on the boom 101. To lower the load into a hatchway or the like, the trolley 103 is run down the boom by means of ropes 117, 117a attached to winding drums until the load occupies the dotted-line position directly over the hatchway after which it is lowered by paying out the rope 107 in the usual way. The bracing rope 108 supporting the boom is connected at one end to an eye on a pulley 109, and passes round the pulleys 110, 109 on the trolley and mast respectively down to a drum 111. The latter drum is mounted on the same shaft as the trolley-traversing drums and is of conical formation to give the desired rates of coiling. Winches.-The winch for performing the various operations comprises a drum 114, Fig. 3 for the hoisting rope, two drums 122 on a parallel shaft for the traversing of the trolley and a third conical drum 111 also on the latter shaft which controls the coiling of the bracing rope. By means of a handoperated sliding member 131 on the main driving shaft 127 the driving-pinion 129 can be moved into gear with the wheel 125 to drive the shaft 116 directly or may be moved into. gear with a loosely-mounted compound wheel on the countershaft 128 which gears with and drives the wheel 125 in the reverse direction. A hand-operated sliding clutch 140 clutches the drum 114 to the shaft 116 at will. The drive of the compound wheel can also be transmitted to its shaft 128 by a hand-operated sliding clutch 134, so that barrels 137 can be driven for performing other necessary operations on deck. Finally a hand-operated clutch 138 can be used to connect the three drums 122 and 111 to the wheel 124 so that they are driven from the wheel 125. During hoisting, the drum 114 alone is driven, but during translation of the trolley along the boom, all four drums are driven. A pedal-operated brake band 143 provides for braked lowering. In a modification the drum 111 is double-conical with the minimum diameter at the centre. Each end of the bracing rope is connected to one of these conical surfaces so that as one end winds off with increasing velocity the other winds on with decreasing velocity and vice versa. This is stated to maintain the boom at a constant angle with the mast during the traversing of the trolley.