CAR LOCKS
22. Several methods of keeping the car on the cage have already been illustrated: by chains, [Fig. 8]; by bails, Figs. [9], [10], and [12]; by omitting sections of the rail under the car wheels, [Fig. 11]; and by dropping a portion of the platform, [Fig. 13]. A very common way is merely to put a pin through the hole in the drawbar and into the floor of the cage. Another common device consists of a brake block that fits between the wheels and can be thrown in from the side by a lever when the car is in place. Another device consists of a yoke, which, by means of a lever, is raised when the car is in place so that it passes about the axle and thus holds the car. A device frequently used on self-dumping cages is shown in [Fig. 22].
Fig. 22
The curved bars a of iron, which just fit around the car wheels as shown, are attached to the loose bars b, on the ends of which are the weights c. When the cage is at the bottom, these weights strike on a cross-piece and are raised to the position shown by the dotted lines, throwing out the bars b, as shown by the dotted line, thus releasing the wheels. The devices shown in Figs. [11], [13], and [22] do not come into action until the cage leaves the landing and the cars must, therefore, be watched until that time.