The Mechanical Handling and Storing of Material

COLLIERY TIPS OR TIPPLERS 593 The speed of the oscillation is slow only during about 10°, while the coal passes from the tippler to the belt or to the intermediate jigging screen. The diagrams, Figs. 836 and 837, show the means by which the varying forward and return oscillations are obtained. Fig. 838 is a side elevation of the actual machine. The shaft G, Figs. 836 and 837, is driven at a uniform speed, the pin g on the crank h1 being connected to an arm, and the toothed segment e1 communicating motion to the pinion b3 and also to the wheel b2, which is geared into the rack a2 attached to the tippler a. One revolution of the shaft G causes the double oscillation of the tipplei through the arc indicated by the dotted lines. It is important to observe that the three equal arcs, g C§1 g2, g2 g3, of this portion of the path of the travelling crankpin correspond, as stated, with the varying velocity of travel of the tippler, as indicated by the letters a a1, a1 a2, and a2 a3, and this variation, as well as the return of the empty 38