IMPROVEMENTS IN LOCOMOTIVE AND TRACTION ENGINES, AND RAILWAY AND TRAMWAY VEHICLES
Year: 1871

page_text: PROVISIONAL SPECIFICATION left by Frederick Henry Trevithick at
the Office of the Commissioners of Patents, with his Petition, on
the 6th November 1871.
I, FREDERICK HENRY TREVITHICK, of 29, Guildford Road, London,
S. W., Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN LOCOMOTIVE AND TRACTION ENGINES, AND RAILWAY AND
TRAMWAY VEHICLES," to be as follows:
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My Invention relates, first, to improvements in the arrangement and
construction of traction engines moving either on a macadamised road or
on longitudinal sleepers of wood, iron, or other material, and a central or
guide rail.
The fire-box of the boiler is arched transversely and slopes down-
wards from the tube plate towards the back plate of the fire-box, in
order to meet the changes of level between the surface of water in the
boiler and the top of the fire-box occasioned by going round sharp
curves and over steep gradients. The boiler is carried upon a wrought-

page_text: iron framing, upon which is also carried the cylinder or cylinders and to
which they are bolted. The crank shaft, an intermediate shaft, and the
driving axle are placed under the framing and boiler. Gear wheels are
provided for affording two speeds of the traction wheels to the speed of
the engines, and also a ready mode of changing the speeds from the foot
plate of the engine, by means of two clutches working on feathers or
other convenient arrangement on the crank shaft. I also use a guard
to prevent the two clutches being thrown into gear at one and at the
same time.
The main weight of the engine I carry upon two traction wheels, to
which are secured break wheels having bands on them, worked from the
foot plate either by a lever, screw, or other convenient mode. The
cylinders I place on an incline over the traction wheels to economise
space, and to obtain steadiness in working and also a better distribution
of weight. The driving axle has outside bearings, and the traction
wheels work between the two longitudinal frames on each side of the
boiler. The axle boxes work in slides or rubbing pieces, and have covers
on the ends which may be readily removed, and the brasses or bearings
taken out and replaced by very slightly lifting the engine and by
removing a packing piece from the top of the brass.
The engine, boiler, and framing are carried mainly upon two springs
placed directly or nearly so over the axle boxes, and in order to enable
the engine to pass easily round curves of small radius I employ a
"bogie" or "bogies," placed at one end or near both ends of the engine,
each bogie having two wheels, both of which are placed in the same
plane and are capable of moving on the same central rail, and of turning
together round a pivot or bearing so placed as to admit of the wheels
adjusting themselves easily to the direction required by the curve of the
road. Or, if preferred, a single wheel might be used instead of two
wheels, having a motion transverse to the direction of the engine to
which it is attached.
In order to the adjusting of the weight of the engine upon its axles,
and in order also to maintain the parallelism of the axles, I employ
water or other liquid acted on by pistons or rams, the cylinders or cases
of which are conveniently placed near the springs, and are so connected
together by a pipe as to permit the liquid to pass from one to the other
as the weight on each varies. I also measure the weight by the use of a

page_text: spring or other guage acted on by the liquid, and vary it by means of a
safety valve or other convenient method..
These improvements also apply to the springs and bogies of tram-
way or railway vehicles for the conveyance of passengers and freight,
and are especially applicable to the Larmanjat or central rail system of
tramways.