THE STEAM ROAD ROLLER

Some road rollers have a boiler of the locomotive type; on these
styles, the engine being a horizontal one, is placed on top of the
boiler, and connected to the driving wheels or back rollers by
means of sprockets and chain, or gear wheels.

In these rollers the boiler forms the principal part of the
frame; the front of it, which forms the smoke box, as in the
locomotive, is built out into ‘the goose neck,’ to which is
swiveled the yoke by means of the king bolt.

The yoke being able to swing, rests upon the axle of the front
roller, which also forms the steering wheel. The horizontal
swinging motion is imparted to it by the steering mechanism, which
consists of chain and worm gear, and is operated by a hand-wheel
near the reversing lever. Figure 1 shows a roller of this type,
which is built by the Harrisburg Car Mfg. Company of Harrisburg,
Pennsylvania.

Other types are built with upright boiler and. engine. In this
type of construction a heavy frame forms the body of the machine
and is carried out into the ‘goose neck’ in front, which
does not differ from the former one described, except the steering
device being attached to the king bolt by means of a lever, is
operated by a screen and nut. The back roller carries the rear end,
and also, in this case, forms the driving wheel.

The boiler is nearly half way between the back and front roller,
resting on the frame, and the engine is attached to it on one side.
It is a double reversing engine, the crank shaft being connected to
the back roller by means of bevel gear and pinion.

A roller of this type is shown in Figure 2, was constructed by
the Erie Machine Shops located in Erie, Pennsylvania.

As will be seen in the illustration, the tank is placed above
the back roller, almost surrounding it. In all road rollers, it is
necessary, on account of unevenness of roads, to allow the front
roller to swing in a vertical plane with its yoke; to accomplish
this the king bolt is not directly fastened to the yoke, but has an
eye on its lower end, through which a bolt passes, which suspends
the yoke on it, and allows it to swing.

In case one side of the front roller should run over a stone, or
any other obstruction, it is thus relieved; otherwise it would put
a heavy strain on the king bolt, and might break it. This
construction is plainly shown in both illustrations.

For breaking up old roads, the rear rollers in Figure 248 are
provided with holes, into which pins are set, which are forced down
into the road bed by the weight of the machine, and by the
revolving of the wheels, break up the surface.