390 APPLIED MECHANICS 
the right the cotter key will engage with the wheel E, and the shaft B 
will be driven through the wheels E and H. ‘The rod R is operated 
by.a lever not shown, which can be locked into definite positions corre- 
sponding to the several positions of the cotter key when in gear or out 
of gear. This form of gear is very suitable for light work, such as is 
required in feed motions of machine tools. 
A form of the sliding wheel change speed gear is shown in Fig. Nag 
There are three E 
wheels, C, D,and , H 
E, rigidly con- = 
nected together : 2 
and carried by 
the driving shaft 
A. A. feather 
key permits of 
Hn 
1 
the wheels C, D, 
and E bein g A drm ee ZZZZZIZL. 2 I 
moved longitudi- WI WG 
nally on A, while Pio} ti WY =i \ | | ( 
at the same time c Vs “ Lf 
they must rotate D 
with A. The Fia..608. 
driven shaft B 
carries three wheels, F, G, and H, which are rigidly fixed to it. By sliding 
CDE into different positions, B may be put out of gear, or it may be driven 
through C and F, or through D and G, or through E and H. 
Another type of change speed gear is shown in Fig. 609. Aisa 
shaft driven at constant speed by a belt on the pulley B. The pinion C 
is keyed to A, and is ares permanently to the wheel E through the 
intermediate wheel 
The wheel E is carried 
by the shaft H, to which C 
it is connected by a pawl 
and ratchet wheel, and if 
H is not driven through 
the other part of the 
gear, to be presently “— 
described, H is driven L 
through C, F, and E. + || == 
The shaft A also carries = ‘te 
a pinion K, which it oP oe i ad 
drives through a feather s 
key. A wheel L carried 
by the sliding tumbler ete 
MN permanently gears with K, and by lifting and sliding MN the wheel 
L may be made to engage with any one of the wheels O, P, Q, R, or 8, 
which are all firmly keyed to the shaft H, or L may be placed clear of 
these wheels. When the shaft H is driven through-the tumbler gear it 
rotates faster than when driven through C, F, and E, but in the same 
direction, this being possible on account of ’the ratchet connection of E 
to H. By using a separate ratchet drive for the slowest speed the shock 
