The Mechanical Handling and Storing of Material

COAL TIPS OR HOISTS 585 pushed forward upon the cradle and put into position. The cradle is fitted with four wheels and ascends on the rails, to the top of the inclined structure, where these rails are so arranged that as soon as the cradle has reached the highest point the front wheels are lowered sufficiently to put the cradle and truck in a posi- tion at which the coal will leave the truck. The engine and winding gear necessary for this installation are placed at any suitable point in close proximity to the tip itself. I he cradle is so balanced that the wind- ing gear has only to perform the actual work of elevating the coal. There is also a safety brake to pre- vent the cradle descending at an ex- cessive speed, even if the cable of the winding gear should snap. I he truck discharges its load into a hop- per, from which it is fed by a shoot into barges. If the hopper is kept full there will be but little breakage in the delivery of the coal, and if carefully manipu- lated by means of the hand wheel the coal will leave the lower end of the shoot at the Fig. 830 Coal Tip Built by Pohlig. same rate at which it enters the hopper. With these tips the tiuck must always be elevated to the same level; they are therefore only suitable for non-tidal rivers and for vessels of uniform dimensions.