The Mechanical Handling and Storing of Material

COAL TIPS OR HOISTS 587 earlier tips it was necessary to have a pit between the rails into which the cradle for the reception of the railway trucks fitted. The crane at the Avonmouth Docks was built for handling coal from the local coal fields near Bristol, from the Radstock district ; foi South Wales coal which comes via Severn Tunnel, as well as for coal from the Forest of Dean and the Midlands. It lifts the truck on the cradle, which is then swung over the hatchway, the coal being tipped into the vessel. A similar tip is also used at Fleetwood. The crane travels on rails laid alongside the quay, and the cradle is so constructed that the trucks can be picked up from and deposited upon the rails at any point where the crane may be. The truck rests on the cradle which fits between the rails, so that the wagon may be run off at the opposite end to the point at which the loaded trucks enter: thus no sidings or turntables are required, and the train of wagons can be lifted and tipped in succession while the empty trucks are taken away on the same line of rails and in the same direction. The cradle is worked by the outside pair of chains, which are manipulated by a different cylinder and ram from the one actuating the tipping. The tipping is arranged from the centre chain, which separates above the swivel, its two strands passing, at this point, over guide pulleys on the lifting beam above the cradle, to which both lifting and tipping chains are attached, the tipping chain being made fast to the rear end of the vessel. The lifting and tipping motions are each controlled by hydraulic power, and are operated by a man standing in a cabin in the front of the crane pillar. A tip similar to that just described is installed at Bremen, Germany.1 With this tip the coal truck to be discharged is run on a platform which forms part of the track passing along the quay side. The crane then picks up this platform with the truck upon it, and swings it round until the end of the car is over a large hopper, which is suspended from the upper arm of the same crane over the ship to be loaded. Ihe truck arrives heie in a horizontal position on its platform, as it has been elevated simultaneously by two sets of hydraulic hoists, one of which is connected to the front and one to the rear chain supporting the platform. By raising the rear chains the platform is tilted until the load has been discharged in this suspended hopper. The manipulator’s cabin is in front of the crane, and in full view of the whole of the operations. The crane has been built for loads of 26 tons, the extension of the jib end being 26 ft., whilst the load can be raised to a height of 32 ft. The special jib which supports the hopper has a radius of 36 ft. and a lift of 45 ft. This installation was built by C. Hoppe, of Berlin. Similar cranes, but of larger proportions, are being built in America. The Cowans Sheldon Crane Tip.2—This is again of similar construction ; it is built by Cowans, Sheldon, & Co., Ltd., of Carlisle, and is intended for loads of 25 tons which are lifted by a single chain. The lifting and turning are effected by hydraulic power, the hydraulic piston being placed horizontally under the quay, and being manipulated from a cabin erected by the side of the jib crane. The radius is 34 ft. 6 in., and the height from quay level to the centre of the jib top pulley is 50 ft. Lewis and. Hunter’s Coal Tip at Cardiff Docks.—This system consists of a tip discharging its load on a level with the line. Self-discharging railway trucks can also be used, in which case the tip is not necessary. The tips, which are mostly used in this system, discharge the coal into a skip which holds the contents of the wagon, and the 1 This tip has been described in a paper read by Mr J. D. Twiriberrow on the “ Capacity of Railway Wagons as affecting Cost of Transport.” See Proc. Inst. Meeh. Engineers. - This tip has been described in Engineering, 29th April 1898, page 531.