The Mechanical Handling and Storing of Material

COAL TIPS OR HOISTS 523 turns on a longitudinal axis. The installation, which is illustrated in Fig. 731, was erected for the purpose of quickly discharging coal, brought from the Maries Colliery, at a small expenditure of driving power. As will be seen from the illustration, the quay wall, which has been constructed by the Maries Colliery Co., is at a sufficient height above the water level to allow of a discharge from the quay to the barges by gravity. This automatic tip is the design of Messrs Taza and Villian, of Annezin. It consists essentially of a substantial platform having a frame of wrought iron, which supports a portion of a railway track of standard gauge. Loaded trucks are pushed on to this platform, and then a very small expenditure of power is necessary to set the tip in motion, whereupon the coal is deposited in an inclined shoot, which leads, by means of an additional piece of spouting, to the river. As soon as the coal has been discharged, the tip returns with the truck to its original position, when the truck is pushed off the Fig. 730. Tip for Power Stations and Factory Yards. platform by the next full truck. This process is an exceedingly simple one, but, as in the case of the appliances previously described, some precaution needs to be taken to prevent a shock, and also to provide for an automatic return of the tip to its original position. To this end a hydraulic brake has been constructed in conjunction with a balance weight. This brake consists of a cast-iron cylinder, 16 in. diameter, which is erected beneath the platform within the quay wall. A piston which fits the cylinder is connected with the platform of the tip by a connecting rod. Both ends of the cylinder are connected to the hydraulic main, the outlets being controlled by valves. Thus when the platform is being lowered during the discharge of the contents of the truck, the piston forces the water out of the cylinder, and by regulating the outlet by means of the above-mentioned valve the process of lowering can take place without shock. The return movement of the platform to its level position is controlled by the balance weight. The truck with its load of 10 tons of coal is pushed upon the platform, which is, by the way, supported upon two