The Mechanical Handling and Storing of Material

6o6 THE MECHANICAL HANDLING OF MATERIAL In the process of hoisting the jib the weights are automatically passed over one by one from the direct line of counterpoise to the line of the dead end by which they are supported. As the hoisting proceeds and the weights are taken up by the dead end, the line of weights on each side of the structure gradually assume the U-shape or festoon form, until, when the jib is housed and almost perpendicular, only two weights a side remain in direct counterbalance. Thus at whatever point in the arc described during the travel of the jib there is always the correct number of weights in direct counter- balance, the others being suspended from the dead end. The jib has also a lateral travel of 12° each side of the centre line allowed for by the pivoted frame and limited by an ingenious arrangement of wire guy ropes. This is necessary to meet the fore and aft ranging of the ship taking in the cargo or bunker coal. The highest position of the jib at which coal can be shipped is 18° above the horizontal. The coal is conveyed by means of an endless belt of steel plates or trays running the whole length of the jib, 54 ft. centres, driven through a friction clutch on the main shaft in the tower and operated from the driver’s cabin in the structure. From this position the driver controls the whole of the operations, electrical and mechanical, the handles for which are all grouped within easy reach, whilst from the cabin window he can watch and guide the movements of the jib. When the jib is sufficiently low for the stream of coal to fall down it, there is, of course, no need to run the belt of steel trays. At the extreme end of the jib a throttle door is fitted to limit the opening for coal; this is controlled by a single wire rope from the driver’s cabin. It is claimed that the whole equipment requires no more for its safe and efficient control than a man of average intelligence exercising ordinary care. The instal- lation, with the exception of the electric motors, was manufactured and erected by Spencer & Co., Ltd., Melksbam, according to the requirements of Mr T. M. Newell, the chief engineer for the docks of the North-Eastern Railway. Other examples are those at the Victoria Dock, Hull, of the North-Eastern Railway. Two belt conveyors, each 42 in. wide, are used for loading 600 tons of coal per hour to a height of 40 ft.; they have, however, done as much as 750 tons. Each of these installations is driven by a 100 H.P. gas engine. At Hartlepool on the staith between the old harbour and the Victoria Dock are eight similar belt conveyors for loading coal, also handling 600 tons, with a maximum of 750 tons per hour; in this case only a 25 H.P. motor has been provided for each. On the Tyne at the Albert Edward Dock several similar belt conveyors are installed, while at their Tyne Dock the North-Eastern Railway have five ; these latter being the first to be used for shipping coal. They are also used at Blyth, while at Whitehaven a belt conveyor shipper has recently been erected fpr loading 500 to 600 tons of coal per hour, and this is fitted with the latest form of anti-breakage device consisting of a spiral shoot, resembling a spiral staircase, for the coal to slide down, which terminates in a revolving shoot at the bottom end for distributing the coal and thus saving trimming. Coal-Shipping Plant at Durban for the South African Railways.—This important plant is one of the latest designs for loading coal from trucks into steamers. It consists of a M‘Myler Car Dumper or Tip capable of handling 75-ton trucks at the rate of fifty trucks per hour. This tip delivers the coal either to a belt conveyor or to a series of railway trucks with bottom door discharge which are handled by an existing transporter. The belt conveyor which receives the coal is fixed on an inclined gantry and conveys, elevates and discharges on to one of two belt conveyors which run parallel to the quay wall. Each of these conveyors is provided with a travelling throw-off carriage or tripper which can discharge the coal at any point along the quay. The