The Mechanical Handling and Storing of Material

COAL TIPS OR HOISTS 551 2 cradle. There is a third ram working in an oscillating cylinder attached to the rear of the cradle for tipping the upper portion of the cradle, which is pivoted at the water side, and by which the discharge of the coal through the end door is effected. The water pressure for this tipping cylinder is taken from the main lifting ram, the action being similar to that of the preceding tip, and a load of 19 tons can be lifted and tipped. I he tips were originally fitted with anti-breakage shoots to reduce the breakage of coal while passing down the shoot, but these were some time ago replaced by ordinary shoots fitted with a single door at the point of discharge for controlling the flow of the coal. The adjustment of the shoot at the proper level and the housing of it when out of use is effected by the cradle itself, the front of which carries levers for taking the weight off the heel of the shoot in raising or lowering it. In the same way the delivery end of the shoot can be raised or lowered by chains, which can be connected to the cradle when necessary. On one side of the framing is a hydraulic anti- breakage crane, with a box of 3 tons’ capacity, similar to the crane previously described. The whole manipulation of the tip is effected by hydraulic cylinders in the usual way, and all machinery is adjustable to suit any conditions. The hoist and crane valves are all operated by a man standing in an elevated cabin on one side of the hoist (see Fig. 776). The tips illustrated in Figs. 777 and 778 1 are by the same designers and makers, and for the same docks. The principal difference be- tween these tips and the one last described is that no part of the machinery is below the quay level. The two lifting cylinders below the cradle in the previous tip are replaced in the present case by four direct acting cylinders, contained in box girders which also form the four guides for the cradle. The lift in these tips is the same, viz., 37 ft., and 'the guides extend some distance above the top of the Fig. 776. Hydraulic Tip at Barry Docks (End View). framing. The anti-breakage crane is for a load of 2 tons and is in other respects similar to the last described. Ihe tips are so airanged that they can at any future time be converted into movable hoists should this be desirable. 2 There are now thirty tips at the Barry Dock, all hydraulically dnven, and 4,000 H.I . are stored up in the accumulators for use at any moment. I his is an actual storage of foot-pounds always at disposal and ready, and at no more cost than the original outlay and the occasional addition of a few more gallons. As to the volume of work done, this is more or less a traffic problem. When ships 1 From Engineering, 22nd March 1896. 2 Remarks made by Colonel F. W. Tannett-Walker during a discussion on a paper read before the Institution of Mechanical Engineers, 20th January and 17th February 1911.