Below the shaft B, and parallel therewith, is a shaft J, which carries a spur gear K, that is constantly in mesh with the pinion E. To the right is a smaller gear L, which is the same diameter as the gear G, with which it is adapted to mesh; and a small gear M, about one-third the diameter of the gear H, is also mounted on the right-hand end of the shaft, which meshes with the gear H, when the latter is moved to the right on its shaft B.
Behind the two gears H, M, is a shaft N, parallel with shaft J, which is so mounted that it has a longitudinal movement, and this carries a broad-faced pinion O, so that it is wide enough to engage with both of the gears H, M, when they are not in line, or in engagement with each other, as shown in Fig. 44.
This latter shaft N, is moved longitudinally by means of the reversing lever P. This lever, together with the gear-shifting lever, hereafter explained, are merely indicated in their present manner, in order to show, diagrammatically, how the gears are shifted.
Low Gear.—The gear-shifting lever Q, in Fig. 42, in this instance, shows the large gear H, moved into mesh with the gear M, so that power is transmitted from the engine shaft A, through gears E, K, shaft J, and gears M, H, to the driven shaft B.
In examining Fig. 43, it will be seen that the shifting lever I, has moved the gears G, H, so they are intermediate to the gears L, M. The mechanism is now at what is called the neutral position, which means that the engine drives only the shaft A, and the shaft J, through the gears E, K.
Intermediate Gear.—Now, when the lever is moved over another step, as in Fig. 44, the gears G L mesh together, and motion is transmitted from the gear E, to gear K, through shaft J, and gears L G, to the shaft B.
Fig. 46. Reverse.
This is called the intermediate, which in this size gears, drives the shaft at half the engine speed, or half of the speed of shaft A, for the reason that gears G L, are of the same diameter, and gears E and K are in the ratio of 1 to 2.
High Gear.—When the lever is shifted another notch, as shown in Fig. 45, the crown teeth F G, of the respective gears E G, engage, and the two shafts A B, are locked together, thus turning the two shafts in unison. This is called direct drive, in which case the shaft B, turns with the engine.