IMPROVEMENTS IN LOCOMOTIVE ENGINES
Year: 1877

page_text: LETTERS PATENT to Alfred Vincent Newton, of the Office for Patents, 66,
"
Chancery Lane, in the County of Middlesex, Mechanical Draughtsman, for
the Invention of "IMPROVEMENTS IN LOCOMOTIVE ENGINES." A communication
from abroad by Henry Clark Wells, of Brooklyn, in the State of New York,
United States of America.
Sealed the 20th April 1877, and dated the 22nd February 1877..
PROVISIONAL SPECIFICATION left by the said Alfred Vincent Newton at
the Office of the Commissioners of Patents on the 22nd February 1877.
ALFRED VINCENT NEWTON, of the Office for Patents, 66, Chancery Lane, in the.
County of Middlesex, Mechanical Draughtsman. "IMPROVEMENTS IN LOCOMOTIVE
ENGINES." A communication from abroad by Henry Clark Wells, of Brooklyn, in
the State of New York, United States of America.
This Invention relates to double piston engines, that is to say, engines having
two pistons in the same cylinder with three piston rods and three connecting rods,
all the piston rods passing out of the same end of the cylinder, two of them being
secured to one piston and one of them, the central rod, to the other piston.
The principal feature of the Invention consists in combining two such engines in
a locomotive with the driving wheels and their axle or axles by means of three-
throw cranks arranged outside of the driving wheels, the cranks being so arranged
with reference to each other that the pistons of one cylinder have their cranks on
centres while the pistons of the other cylinder have their cranks in the half stroke
position. This improvement is applicable to engines having two, four, or any
number of driving wheels.
When more than one pair of driving wheels is used, each wheel of the first pair,
that is to say, the pair to which the power of the engine is first transmitted by the
three-throw cranks as above mentioned, may be connected with the corresponding
wheel of the next pair by one, two, or three coupling rods. When three coupling rods
are used, the second pair of drivers will be furnished with three-throw cranks like
those on the first pair, and the connections of the couplingrods will be made between,
corresponding crank pins on the cranks on the first and second driver. When one-
coupling rod only is employed, of course only a single crank will be required on

page_text: each driver of the second pair, and when two coupling rods are used a two-throw
crank will be required on each of said drivers. The same system of coupling may
bo carried out from one pair of drivers to another when more than two pairs are
used.
Another feature of the Invention consists in the method of attaching the three-
throw cranks to the driving wheels, which affords facility for applying them to
locomotives already built using the old driving wheels, the distinguishing character-
istic of this method being that, the crank pin nearest the wheel is carried by a plate
which is secured at both ends to the driving wheel.
In carrying out this Invention it is preferred to use the ordinary short slide valve.
In order to provide for the use of such valve another feature of the Invention consists
in a novel construction and arrangement of the passages and ports of the cylinder
of a double piston engine, the distinguishing peculiarity of which is that the steam
and exhaust passage proper to one end of the cylinder is twisted round the exhaust
passage leading to the exhaust pipe, so that the former passage connects with the steam
and exhaust passage belonging to the other end of the cylinder. Both of these steam
and exhaust passages connect therefore with the same port in the valve seat, so that
when the valve is at one end of its stroke steam may exhaust from both ends of the
cylinder through the same port into the valve cup, and when the valve is at the
other end of the stroke steam may enter through the same port in the valve seat
and flow through the passages leading to opposite ends of the cylinder.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alfred Vincent Newton in the Great Seal Patent Office on the
22nd August 1877.
ALFRED VINCENT NEWTON, of the Office for Patents, 66, Chancery Lane, in the
County of Middlesex, Mechanical Draughtsman. "IMPROVEMENTS IN LOCOMOTIVE
ENGINES." A communication from abroad by Henry Clark Wells, of Brooklyn, in
the State of New York, United States of America.
This Invention relates to double piston engines, that is to say, engines having
two pistons in the same cylinder, with three piston rods and three connecting rods,
all the piston rods passing out of the same end of the cylinder, two of them being
secured to one piston and one of them, the central rod, to the other piston.
The principal feature of the Invention consists in combining two such engines in
a. locomotive with the driving wheels and their axle or axles by means of three-
throw cranks arranged outside of the driving wheels, the cranks being so arranged
with reference to each other that the pistons of one cylinder have their cranks on
centres while the pistons of the other cylinder have their cranks in the half stroke
position. This improvement is applicable to engines having two, four, or any
number of driving wheels.
When more than one pair of driving wheels is used, ench wheel of the first pair,
that is to say, the pair to which the power of the engine is first transmitted by the
three-throw cranks as above mentioned, may be connected with the corresponding
wheel of the next pair by one, two, or three coupling rods. When three coupling
rods are used, the second pair of drivers will be furnished, with three-throw cranks
like those on the first pair, and the connections of the coupling rods will be made
between corresponding crank pins on the cranks on the first and second driver.
When one coupling rod only is employed, of course only a single crank will be
required on each driver of the second pair, and when two coupling rods are used a
two-throw crank will be required on each of said drivers.. The same system of
coupling may be carried out from one pair of drivers to another when more than
two pairs are used.

page_text: •
Another feature of the Invention consists in the method of attaching the three-
throw cranks to the driving wheels, which affords facility for applying them to
locomotives already built using the old driving wheels, the distinguishing character-
istic of this method being that the crank pin nearest the wheel is carried by a plato
which is secured at its opposite ends to the driving wheel.
In carrying out this Invention it is preferred to use the ordinary short slide
valve.
The Invention is illustrated in the accompanying Drawings, in which,―
Figure 1 is a side elevation partly in section of parts of a locoinotive engine con-
taining this Invention.
Figure 2 is a plan partly in section of the same parts, the boiler being removed.
Figure 3 is a diagram illustrating the arrangement of the steam ports and passages
in a plane parallel with the face of the valve.
Figures 4, 5, and 6 are vertical sections of a locomotive driving wheel with a
crank applied thereto.
Figures 7 and 8 are diagrams illustrating the relative positions of the cylinder
of an ordinary locomotive engine and the cylinder of this improved engine.
Figure 9 is a face view illustrating a method of construction of the hub of a driving
wheel.
In order to carry out this Invention, the cylinders are located in the usual place
of outside-connected cylinders, except that the axis of the cylinder is a little (a few
inches) farther out from the longitudinal centre line of the engine than usual. Fig. 8
shews the position of an ordinary outside-connected cylinder, A representing the
cylinder; B, the saddle; and D, the framing; while Fig. 7 shews the position of the
outside-connected cylinders in the improved engine. Observation of the dotted
lines will shew the amount of the change in position from the old to the new
arrangement. These cylindera, as before stated, have each two pistons E, F, three
piston rods G, G, H, and three connecting rods C, D, D₁ (see Figs. 1 and 2), the
two piston rods G, G¹, being connected with the piston E, and the central piston.
rod which passes through a stuffing box in the piston E being connected with the
piston F. The said cylinders have also proper stuffing boxes, guides or slides,
brasses, stub ends, &c., and a valve and ports constructed so as to admit and exhaust
the steam properly.
The arrangement of valve and ports shown in the Drawings at Figures 1 and 3
is preferable. In this arrangement the steam and exhaust passage leading from one
end of the cylinder is twisted around the exhaust passage leading to the exhaust
pipe, so that the former connects with the steam and exhaust passage from the
other end of the cylinder. Both of these steam and exhaust passages connect
therefore with the same port in the valve seat, so that when the valve is in the
position shown in the Figure, steam may exhaust from both ends of the cylinder
through the same port into the valve cup, and when the valve is at the other end of
its stroke may enter through the same port in the valve seat, and flow through the
passages leading to opposite ends of the cylinder. This arrangement and con-
nection-of passages allows of an ordinary short slide valve being employed in a
double piston engine.
Each of these engines is combined with the driving wheels and their axle, or
with the first pair of driving wheels and their axle when more than one pair of
driving wheels is used, by means of a three-throw crank I, arranged outside of the
driving wheels, care being taken that the cranks are so arranged with reference to
each other that the pistons of one engine shall be in the centre of their stroké and
in position to do their best work when the pistons of the other engine are at one
end or the other of their stroke; or, in other words, the cranks must be so arranged
that the pistons of one engine have their cranks on centres while the pistons of the
other engines have their cranks in the half stroke position.
Various plans of attaching these three-throw cranks to the driving wheels will be
hereafter described; but the cranks may be made and secured to the wheels in any

page_text: way known to mechanics, provided that they are arranged with reference to each
other as heretofore stated.
By properly proportioning each part of the crank, including the pins, the crank
as a whole may be so made that equal parts of its weight will lie on opposite sides
of the centre of the driving wheel, and by making the centre connecting rod C of
the same weight as both of the connecting rods D, D¹, the connecting rods of cach
wheel will balance each other. It will thus be understood that the weight and
momentum of the moving parts may be exactly balanced for each wheel. Thus the
connecting rods of each wheel balance in their forward and backward and up and
down motions not only in weight but in speed and extent of their motions. Tho
same is true of the cranks of each wheel, and the same of the forward and back-
ward motions of the pistons and piston rods, provided care is taken that one piston
with its two rods and cross heads is of the same weight as the other piston with its
single piston rod and cross head. In addition to these results there will be little or
no force exerted to move either end of the axle to or from the engine that is acting
on that end, because when the single connecting rod is trying to drive the axle
away from the cylinder the two connecting rods are striving to pull the axle
towards the cylinder. In ordinary locomotives this effort of the engines at times
either to pull the axle bodily to or away from the cylinder and at other times to
push one end of the axle away from its cylinder while the other end is being pulled
toward its cylinder, keeps a constant strain upon the boxes, increases friction and
wear, and is generally considered to be the great source of unsteadiness of locomotives..
It may be further stated that all locomotive driving wheels support the engine
through the intervention of springs, consequently the axles and cranks thereto
attached are constantly moving up and down with reference to the centre line of
the cylinder, and the centres of the axles are only momentarily in line with the
centre line of the cylinder, even when those centre lines are in modern fashion in
the horizontal plane which passes through the centre of the driving wheels. In
such engines during their revolutions both connecting rods are sometimes tending
to move both ends of the shaft downward, and at other times one connecting rod is
striving to move its ends of the shaft downward, while the other connecting rod
is striving to move its end of the shaft upward. As there are springs this motion
actually takes place, and the boiler and engine proper are consequently kept in a
state of oscillation owing to the compression and expansion of the springs due to
this action of the engine. This Invention remedies this defect by reason that the
two outside connecting rods of each engine always tend to throw the shaft in exactly
the opposite direction to that in which the central connecting rod tends to push it.
There is therefore in this locomotive no tendency either to contract the springs or to
permit them to expand, much less a tendency to contract the springs on one side
while the other is permitted to expand, as is the case in ordinary locomotive
engines.
'
The advantages of this Invention, therefore, may be summed up as insuring a
greater extent of steadiness of motion, as obviating friction and wear to a certain
extent, and as a consequence thereof the use of less fuel and steam to do the same
work.
The foregoing description has only been made with reference to the use of a
single pair of drivers. When two pairs are used the second pair may be furnished with
three-throw cranks I', as shewn in Figures 1 and 2, similar to the three-throw cranks I
on the first pair, the three crank pins of each crank I being connected by as many
coupling rods J, K, K¹, with the corresponding crank pins of the cranks on the next!
pair. These coupling rods may be made to balance each other in the same way as
the connecting rods by making the central rod J as heavy as the two K, K¹. If
only one or two coupling rods be used only a single crank or a two-throw crank, as
the case may be, will be required on each of the drivers of the second pair. The
same system of connection by coupling links may be carried out from the second
pair of drivers to a third, and so on, when more than two pairs of drivers are
used.

page_text: As herein-before stated this Invention is applicable to locomotives already built
using the old valve gear and driving wheels; and to provide for using the old driving
wheels a plan for constructing the crank and attaching it to the wheel is illustrated
by Figures 4 and 5, which represent two modifications of the plan. In both these
modifications the three-throw crank has its crank pin a nearest the wheel attached
to a wide flat plate e¹ which extends from the outside of the old crank pin hole to
or beyond the axle c of the driver. This plate is by preference forged in one piece
with a pin b which passes through the old pin hole, and is secured there by a nut f,
the fit between the pin and hole being a tight one. The other end of this wide
plate has either a socket d as in Fig. 4 or a pin e as in Fig. 5 forged upon it, and
this socket or pin is forced by means of a press into a recess fitted to receive it, this
recess being bored out either in the axle or the hub or partly in both. This con-
struction fastens the crank securely, preventing it from being twisted, as it might be
if secured to the wheel at one point only.
As it is intended when altering old locomotives that the length of stroke of each
piston should be about half the length of stroke of the old single piston engine, the
crank pin a will be nearer the centre of the wheel than the old crank pin.
With new locomotives or new driver the hubs may be made elliptical (as shewn
at Fig. 9). The axle will in this case enter beyond the face of the wheel, the
wide plate e being hored out to receive it (see Fig. 6).
It will be seen that these modifications all have the same feature, vizt, that the
inner crank pin is attached to a plate, which latter is attached at both ends to the
driving wheel.
Although the ways preferred for attaching the three-throw cranks to the drivers
have been described, it must be understood that the Invention pemits the use of
cranks attached or constructed in other ways, so long as they are three-throw, are
outside of the drivers, and arranged on the opposite drivers relatively, as before
described.
Having now set forth the nature of the Invention of "Improvements in Locomotive
Engines," as communicated to me by my foreign correspondent, and explained the
manner of carrying the same into effect, I wish it to be understood that under tho
above in part recited Letters Patent I claim,-
First. The combination of two cylinders, each provided with two pistons and
three piston rods and three connecting rods, with two driving wheels and their
axlo by means of two three-throw cranks, arranged outside of the drivers and in
such relation to each other as herein described, the combination being and acting
substantially as herein set forth.
Secondly. In combination with two cylinders, each provided with two pistons,
three piston rods, and three connecting rods attached respectively to one of a pair
of three-throw cranks of a driving wheel axle of a locomotive engine, I claim two
or more additional driving wheels, furnished each with a three-throw crank, and
coupled with another driving wheel on the same side of the locomotive by means
of three coupling rods, substantially as herein described.
Third. The construction of crank coupling substantially as herein described,
whereby a three-throw crank is attached to the face of a driving wheel, the crank
pin nearest the wheel being secured to a plate which is made fast at its opposite
ends to the driving wheel, substantially as herein set forth.
In witness whereof, I, the said Alfred Vincent Newton, have hereunto set my
hand and scal, the Twenty-second day of August, in the year of our Lord
One thousand eight hundred and seventy-seven.