464
STEPHENSON’S PATENT
Fig. 42.
to each other, and will remain parallel when moved up and down. Each side,
CC, has a small projection on its inner side, fitting into a corresponding groove
in each wedge, as shown in fig. 41, to guide it when moved; and a bolt, F.,
is carried upwards from each of the wedges E, through the upper piece E, having
a nut screwed upon it at the top; the holes for the bolts are made oblong to
allow for the lateral motion of the wedges
when they are screwed up. The two
brass bearings, G G, are inserted be- £ ~
tween the wedges, having flanehes on j
each side fitted on the faces of the
wedges; they are three inches wide,
and bored out to five inches diameter, to
fit the cranked axle. One of the brasses,
G, overlaps the other, which is fitted
steadily into it, but not quite touching
at the ends. They are made to close
upon the axle by screwing up the two
wedges E E, thereby forcing the two
brasses nearer together; and they are
then free to slide up and down between
the wedges to allow for the play of the
springs, which affects the engine only
and not the axle ; and are readily tight
ened up as they wear from friction, by
screwing up the wedges farther.
The cranked axle is thus steadied against the horizontal force of the connect
ing rods, which is the greatest strain that it is subjected to; but it can have no
vertical support in consequence of the play of the springs. A shoulder is made
on the bottom of the nuts on the bolts E, and cut into teeth, as shewn in the
plan, fig. 44, which catch the ends of a small spring H, fixed by a screw in the
middle. This prevents the nuts from turning round and getting loose with the great
jolting to which they are subject, the spring having to be forced out from each
tooth in succession to let the nut turn ; and though this does not impede the
screwing up of the nuts, it is sufficient to prevent their getting loose. The same
contrivance is applied to all the nuts in the engine that are used for the adjustment
of some moveable part, as those in the glands of the piston rod and slide valve
spindle; as these nuts are not screwed hard up so as to keep them fast.
Some engines with four wheels are made without the outside frame, and also
lQj|
H
Figs. 43 and 44.