The Mechanical Handling and Storing of Material

532 THE MECHANICAL HANDLING OF MATERIAL then brought back by means of the counterbalance weight, no machinery being required under ordinary working conditions. Should it be found necessary to return part of the contents of a wagon when completing the loading of a boat, this is done by means of a small electric motor with gear, provided for the purpose. The apparatus has now been working successfully for a considerable time and is capable of dealing with 500 tons of coal per hour. B—Tips which Unload on the same Level as the Railway Lines, or Slightly Above.—Tips of this description are manipulated by raising one end of the truck in order to unload it, the reverse process having been followed with the tips previously described. There one end was lowered beneath the level of the rails for the discharging process, which allows of unloading with practically no expenditure of driving power. Tips that unload on the same level as the rails must in all cases be actuated by hydraulic or other power. Tips of this type are made of two kinds : either a portion of the rails is laid on a' platform, which latter is raised mechanically at one end to unload the truck which is held in position upon this platform, or the truck remains with one pair of wheels on the ordinary track, whilst the other end of the truck is raised by lifting the back axle. The former type is more costly, but it has the advantage that the trucks can be tipped to a steeper angle without the buffers coming in contact with the rails, whilst with the latter type the buffers will touch the rails before the platform of the wagon is at a sufficiently steep incline for some materials, such as damp coal, to clear the truck without assistance. What has been said in reference to the disposal of the material with regard to tips ot type A applies also here, with the difference that if an excavation is necessary it may only have to be 15 to 20 ft. deep, instead of 20 to 30 ft. in depth, but such an excavation is still a very costly undertaking which reduces the usefulness of the tip more or less if economy is studied. The Power Tips of the Great Western Colliery Co., Pontypridd.—The annexed illustration, Figs. 745 and 746, is the design of Mr Davison, engineér of the Great Western Colliery Co., Pontypridd. It shows the apparatus in a longitudinal and cross section. The trucks to be emptied by this tip must be provided with hinged end doors. The main feature of this tip is that it can be operated by a motor or by a belt from any existing shaft. The rails remain unbroken, and the apparatus can be used without interfering with the traffic on the siding. It is evident that there are many cases in which such a tip can be used with great advantage. It will be seen from the illustration that the rear axle is brought over the ram-head a when the lever b is thrown over, which causes the friction clutch to engage with the worm shaft actuating the drum, and thus winds the chain which lifts the ram. Radial rods c are fixed to the ram-head and prevent the truck from moving out of its position during the lifting process. The ram passes through a cast-iron sleeve d with trunnions guiding it in the course given by the radial bars, and when the truck is tipped the lever is moved to the opposite side. This causes the reversal of the gear and the consequent lowering of the truck on to the rails again. The time occupied in tipping the truck is about one minute. These tips are built by Sheppard & Sons, Ltd., of Bridgend. The Double Tip at the Cardiff Corporation Electricity Works.—Where it is more convenient for any reason to manipulate tips from above instead of below, a very useful device is the one here described and illustrated in Fig. 747. It was designed by Sheppard & Sons, Ltd., Bridgend, to meet special requirements where space did not