GB714071A - Improvements in or relating to apparatus for lifting, lowering or otherwise handlingloads - Google Patents

Abstract

714,071. Safety retaining mechanisms; winches; load handling machines: cranes with telescopic jibs; lifting cradles. KING, D. M. June 19, 1952 [June 25, 1951], No. 15057/51. Classes 78(3), 78(4) and 78(5) A load handling apparatus particularly for loading and unloading ships comprises a tower 10 running on tracks 11, a slueable telescopic boom 13, a telescopic member 15 rotatable about its vertical axis and a vertically movable load carrier 16, 17. Telescoping of the boom 13 can be effected by a screw, winch, rack, and pinion, hydraulic or friction drive mechanism, whilst the member 15 is telescoped by a winch mechanism and is provided with catchgear to lock the sections together in the event of a cable breaking. The load carrier comprises a fork or platform 16 mounted adjacent the operator's cab 18 on the lowest section of member 15 and has castors and a hook 17 mounted on its underside. In a modification (not shown) the member 15 is mounted on wheels for movement along a rigid boom 13. Safety retaining mechanisms. This mechanism is shown in Fig. 6 and comprises a double arm lever 28, 30, mounted on a telescoping section 25 and biased by a weight 36, or a spring (not shown), into a position in which a pulley 30 engages a run of the hoisting cable 29. If this cable breaks the lever 28, 35 is allowed to rotate anti-clockwise so swinging levers 37, 38 and thus causing toothed cams 39 to engage the outer section 25a. In addition, movement of the cams operates a switch 44 which de-energizes the winch driving motor. The pin and slot connection between lever 28, 35 and levers 37, 38 allows a small amount of lost motion before the cams operate. A similar mechanism is mounted between each pair of sections of the member 15. In a modified arrangement, Fig. 7 (not shown), a double mechanism, each part of which is similar to that shown in Fig. 6, co-operates with a pair of hoisting cables, the arrangement being such that a single pair of cams are actuated on the breakage of one or both of the cables. Winches. To ensure that the orientation of the vertical run of the hoisting cable remains constant during winding, a special winch is provided comprising a helical slotted drum 21, Fig. 2, around which the cable is wound, and which engages a fixed nut 23 which causes the winch to move horizontally on wheels 20 as the drum is rotated. Ir. a medication (not shown) the helical slots are cut in a cylinder separate from the drum but rotatable therewith. The winch mechanism includes means (not shown) which automatically compensates for the rise and fall of the ship. An automatically adjustable weight (not shown) is provided at 14, Fig. 1, to counterbalance the load on the carrier. In a modification (not shown) there are provided pairs of booms 13 and members 15. The carrier and member 15 may be adjustable as described in Specification 696,581.