Page:Motors and motor-driving (1902).djvu/159

Rh cam, until it occupies the position ', shown in the dotted lines. This position is also illustrated in fig. 16, but of course seen from a different aspect.

When the hammer rests in this position on, the arm , fig. 15, is pushed so far forward that the diggers of the two cylinders both miss the shoulders  and both exhaust valves remain closed, the speed of the engine immediately begins to slacken, and weights  fig. 17, begin to return to their position of rest at. Thereupon the hammer ' slips back on to the cam ', and allows one exhaust valve to open, and one cylinder to come into action. If this is sufficient to run the car and engine at their maximum speed, as for example when descending a slight incline, the hammer remains there and only one cylinder works. If it is not sufficient, the weights still further approximate to, and the hammer slips back to the original position on the circular collar , whereupon both exhaust valves open in turn, and both cylinders work at their full capacity.

, shown further along shaft, is the cam similarly lettered in figs. 14 and 15, which bears against roller, and lifts arm , which in turn raises the exhaust valve.

In figs. 14 and 15 we have only been able to show the way the cut-out motion works in connection with one cylinder. Fig. 18 depicts both, the lettering remaining the same.

As shown in this figure, rests on the circular collar, and consequently neither cylinder will cut out. When shifts on to the next cam, however, it is slightly depressed, as already explained, and thereby the arm  is pushed forward, and the digger at the end of  misses the shoulder, whereupon the inner cylinder cuts out.

Seeing that the bracket is in one piece, and is actuated by, our readers will naturally wonder how it is that the further cylinder does not cut out at the same time. If they will examine the arm 1 in the second cylinder, they will observe that it is divided into two parts, and that the outer part, 2, telescopes into the inner. Consequently 1 cannot be