514 GASOLINE AUTOMOBILES

Advantages of CanHhser. The advantages of the cantilever
spring are the smaller unsprung weight and the reduced manufac-
turing cost for a given amount of flexibility. Another advantage is
tiie absence of sharp rebounds and a greater deflection for a given
load and length of spring; it also obviates the cut in the body required
with the three-quarter elliptic spring. When the cantilever takes the
driving strain, the main leaf is usually stifFened and, being stronger
sidewise, it eliminates a good deal of the side sway. With torque
rods, the main lead may be made lighter, as the starting, the braking,



Fie. ^3. Uuiqae Rear Spriua ol Maimou Cua

and the torque' act through the torque rods. Since there is more
metal in the line to the thrust, they are especially suitable for taking
the thrust, and not quite as efificient in taking the torque.
Hotchkiss Drive. The adoption in 1915 of the Hotchkiss drive,
Fig. 402 in which the rear axle is connected with the frame through
the chassis springs only, making the springs perform the functions of
torque and thrust, is a radical departure from previous forms. The
objection that it subjected the springs to unnecessary strains has not
been sustained in practice, which has shown that a slight yielding of
the rear axle when starting and braking, by a certain flexure in the
springs, has reduced the stresses upon the transmission members.
GASOLINE AUTOMOBILES



515



In the Hotchkiss drive, the springs are rigidly attached to the rear
axle, while the front end of the spring is secured to the frame with a
proportionately large bolt through which the drive is transmitted.
