CERTAIN IMPROVEMENTS IN LOCOMOTIVE ENGINES
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by John Henry Johnson at the Office
of the Commissioners of Patents on the 31st May 1880. A communication
from abroad by William Peddle Henszey, of Philadelphia, Pennsylvania,
United States of America.
"6
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. CERTAIN IMPROVEMENTS IN LOCOMOTIVE ENGINES." A communication
from abroad by William Peddle Henszey, of Philadelphia, Pennsylvania, United
States of America.
This Invention relates to that class of locomotive engines in which one pair only
of driving wheels is used, and the object of the Invention is to enable the engineer
to readily increase the weight upon the said driving wheels so that they may have
the proper adhesion for starting the engine and train, and, after they are in motion,
to transfer part of the weight to the trailing wheels, which take the place of the
usual second pair of driving wheels.
In carrying out this Invention it is preferred to make the barrel or body of the
boiler of an oval form, and the fire box much wider than those of ordinary
locomotive boilers, the oval shape of the barrel or body being necessary in order
that the aggregate tube area may be proportionate to the increased heating surface
of the fire box which is required for engines of high speed; the major axis of the
oval is vertical, an appropriate number of tubes being thus contained in the
contracted space between the driving wheels.
•
The locomotive has but one pair of driving wheels, and in place of the ordinary
rear driving wheels a pair of trailing wheels are used, the object of this arrange-
ment being to dispense with the connecting rods by which two pairs of drivers are
coupled together, for one of the great sources of danger in locomotives running at a
high speed, for which these engines are intended, is the breaking of these connecting
or coupling rods.
In a locomotive with but one pair of driving wheels, however, it is essential that
there should be sufficient weight upon them to insure the proper adhesion for
starting the engine and train; but this excessive weight on the driving wheels is
not only unnecessary when the engine and train are in motion, but is injurious to
the track; the object of this Invention, therefore, is to provide means whereby the
excess of weight on the driving wheels required in starting the engine and train
may be transferred to the trailing wheels.

page_text: The boxes of the axles of the driving and trailing wheels are adapted to guides
in the frames in the usual manner, and carry the springs on which the engine rests.
Taking one side of the engine as an example of the arrangement of both sides, a
compensating beam is connected at one end to the spring for one of the boxes of
the driving axle by an ordinary link, the opposite end of the beam being connected
to the spring for one of the boxes of the axle of the trailing wheels through the
medium of links and a lever, against the underside of which bears the box of the
axle of the trailing wheels. To the frame is adapted a movable fulcrum for the
compensating beam. The nearer this fulcrum is to the driving axle the greater
will be the weight on the driving wheels, and the less will be the weight on the
trailing wheels, the weight on the latter increasing as the fulcrum is moved away
from the driving axle and towards the axle of the trailing wheels. One side of
the engine only is referred to in the preceding description, but the other and
opposite side of the engine is precisely the same, and is provided with appliances
exactly like those described above.
The two fulcrums of the beams should be under the control of the engineer, who
should be able to change their positions by any appropriate system of levers and
rods or other appliances, or the fulcrums may be operated by the aid of a small
steam cylinder, the valve of which should be controllable by the engineer, who
can, by changing the position of the fulcrums, impart a greater weight to the
driving wheels on starting the engine and train, and, after the latter is running,
can transfer the excess of weight to the trailing wheels so that the latter and the
driving wheels will sustain the same weight.