IMPROVEMENTS IN TRACTION ENGINES
Year: 1881

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for an Invention of "IMPROVEMENTS
IN TRACTION ENGINES." A communication from abroad by Abraham
Oppenlander Frick, of Waynesboro, Franklin County, State of Pennsylvania,
United States of America, Machinist.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents on the 12th April 1881.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN TRACTION ENGINES." [A com-
munication from abroad by Abraham Oppenlander Frick, of Waynesboro, Franklin
County, State of Pennsylvania, United States of America, Machinist.]
This Invention relates to certain improvements in road engines designed to
improve their construction and operation. The principal features of improvement
consist in the structure of the framework and means for hanging the boiler therein
to compensate for expansion; in the means for connecting the engine and the
frame so as to avoid working strain on the boiler sheets; in the construction and
arrangement of the front truck; in the means for guiding the engine, and in the
construction of the traction wheel, all as hereinafter more fully described.
The main frame of the engine consists of a pair of iron sills made in the form
of channel bars, extending the full length of the engine from the front truck to a
point some distance in rear of the boiler. At the point where the sills extend
beyond the rear of the engine they form a support for the platform for the use of
the driver and fireman, and a support also for the water tank, which is suspended
from the underside of the same. These sills while constituting the main frame
are in no-wise bolted or rigidly attached to the boiler except at one point, where
they are connected by angle irons on each side. There being but this one
connection with the sills, it is obvious that the expansion and contraction of the
boiler is in no wise affected by the said sills. The boiler is supported at other
points by a loop or stirrup strap hung to the sills in the rear and by an expansion

page_text: joint with the front truck, as will be hereafter described. This stirrup or loop
carries the principal part of the weight of the boiler, and relieves the sheets of the
boiler from all strain caused by carrying it in brackets or, plates which are usually
bolted to the sheets.
Metal side plates are bolted to the iron sills on each side of the boiler, and
extending vertically therefrom. Each of these plates has a slot or notch at its
lower side which slips over the axle to brace it and has at the top two levels,
the lower one of which carries the bearings for the counter shaft, and the upper
one of which levels is bolted to the end of the engine which carries the crank shaft.
This end of the engine frame is formed like a saddle, which straddles the rear end
of the boiler but is not rigidly attached to it. The lower section of the two
bearings for the countershaft are formed in one piece, being connected by a flanged
and trough shaped bar which serves as a brace to connect the two side plates
firmly together. These side plates carry the weight of the rear end of engine
frame, crank shaft, flywheel, and pillow block, and carry all the working strain,
thus entirely relieving the boiler of the same. The engine frame, it will be seen,
rests at its back end upon the top of the side plates, as before described, while at
its forward end it rests upon the boiler. It is not rigidly attached to the boiler
at this point, however, but has an expansion joint to prevent strain occuring
between the said frame and boiler due to the heating and cooling of the latter.
This joint is formed of a plate or casting rivetted to the boiler, and shouldered
bolts which pass through longitudinal slots in the flange of the engine frame, so
that after the bolts are tightly screwed down the engine frame still can slide
longitudinally by reason of its slots over the plate to permit the expansion and
contraction of the boiler without strain, the plate being provided with side flanges
preferably to co-operate with the shoulder bolts in preventing side movement.
For steering the engine the front axle is arranged to turn about a vertical centre,
and a chain is attached to one side of the axle and thence extends rearwardly to a
roller or drum around which it is wrapped several times and is then returned to
the axle on the other side of its pivot, so that by revolving the drum one way or
the other the chain is wound up on one side and unwound on the other to change
the position of the front axle from a right angular position to an oblique one to
cause the turning of the engine. This drum extends transversely across the
machine beneath the boiler, and it is carried by a hanger bolted to the main sills.
For rotating this drum a worm wheel is arranged at one end and a worm made
to gear therewith, which worm is carried by a shaft extending to the rear, and
carrying a hand wheel in convenient position for the driver. This steering
mechanism as so far described I do not claim as new. With such a chain gear
however I find that when the front truck axle is arranged obliquely the chain
does not equally wind up on one side and unwind upon the other, and furthermore
in running against obstacles it sometimes happens that one front wheel will strike
an obstruction and throw the axle around, leaving it in the position which causes
the engine to run out of its course, and involving also a damaging strain upon the
connection. For avoiding all these objections I place in the length of the chain on
each side, and preferably near the axle, an elastic spring of either a spiral piece
of metal or a block of rubber. This may be in the nature of an elastic link in the
chain, or it may be a spring attached directly to the axle on each side of its central
pivot. This it will be seen allows the chain to give and compensate for the
unequal winding, and if one wheel strikes an obstruction the spring relieves the
gears of strain, and also immediately restores the axle to its proper position.
For connecting the boiler to the front axle a box plate has a curved upper
surface adapted to fit the bottom of the boiler, and is slotted lengthwise the boiler,
and is connected to the boiler by shoulder bolts, which when screwed to the boiler
tight allow the latter to move lengthwise of the plate to compensate for expansion.
This box plate is bolted between the forward ends of the side sills and is connected
with a yoke plate by a vertical bolt about which the circular upper end of the
yoke turns after the manner of a fifth wheel. This yoke plate receives a cap plate

page_text: which passes through it and is fulcrumed to it by a bolt. This cap plate has two
chambers, one upon each side of its fulcrum, in which are contained springs that
bear upon the axle of the front wheels. This axle passes through the cap plate,
and is provided with two clips which are rigidly connected with the axle and serve
to hold the cap plate in proper position upon the axle. A brace extends from the
bottom of the yoke plate to the sills for the purpose of resisting the strain involved
in running against obstructions.
I will now describe an improved traction wheel, being a spoked wheel having a
toothed or fluted tire for better engagement with the earth and a hub of large
diameter. Within this hub is arranged a stationary box having a circular periphery,
which with the inner surface of the hub forms the lubricated joint of the wheel.
This box has in its middle a vertical chamber with straight guide walls, within
which is contained a smaller box, having a square horizontal hole through it which
receives the axle. Within this chamber and beneath the box carrying the axle are
spiral springs, which form an elastic connection between the load on the axle and
wheel. The box is held in the hub of the wheel against slipping out laterally by a
head plate on the outer end of the axle and a corresponding plate at the opposite
end, which latter is formed in one piece with the inner box, the two plates being
fastened together by bolts.
A gear wheel is attached concentrically to the side of the running wheel and
bearing teeth, which mesh with the teeth of the driving wheels. This wheel has a
hub that turns on a peripheral bearing of the plate, and it is attached to the
traction wheel in a peculiar manner. Thus to the side of the spokes of the traction
wheel I attach strongly by bolts a circular band of metal carrying lugs, while upon
the arms or web portion of the gear wheel are formed other lugs. These sets
of lugs I then connect by spiral springs which have the following important
functions.
The gear wheel it will be seen must from the necessity of the case be immovable
with respect to the driving gears with which it meshes and by which it is driven.
Now the result sought by me is to get a traction wheel (which has the function of
a driver as well as that of a passive running wheel) which will always be in gear
with the driving devices, and yet be permitted to vibrate in right lines as it passes
over rough ground, or in other words, a traction wheel which is not necessarily
concentric with its axle. This result is attained by the springs, for although the
gear wheel is always rigid and immovable, the running wheel vibrates in its plane
with a universal spring connection capable of oscillation throughout the 360
degrees of the circle, and producing varying strains on the springs sometimes
endwise and sometimes sideways, sometimes a tension and sometimes a compression.
It is this connection of the gear wheel and running wheel which makes a spring-
seated axle possible in the hub of a traction wheel, for without this said connection
the running wheel could not be an active or propelling. wheel without having its
centre concentric with its axle, and a constant distance from the centre of the gear
wheel which drives it. Incidentally these springs also cause the rotary strain on the
running wheel to be a yielding one.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Great Seal Patent Office on the
7th October 1881.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN TRACTION ENGINES." A com-
munication from abroad by Abraham Oppenlander Frick, of Waynesboro, Franklin
County, State of Pennsylvania, United States of America, Machinist.
This Invention relates to certain improvements in road engines designed to
improve their construction and operation. The principal features of improvement
consist in the structure of the framework and means for hanging the boiler therein
to compensate for expansion; in the means for connecting the engine and the frame
so as to avoid working strain on the boiler sheets; in the construction and arrange-
ment of the front truck; in the means for guiding the engine, and in the
construction of the traction wheel, all as hereinafter more fully described.
The Invention is illustrated in the accompanying Drawings, in which Figure 1 is a
side elevation; Figure 2 is a rear end elevation with the side plates D and sills A in
vertical section; Figure 3 shows details of the counter shaft bearings and transverse
brace for the side plates; Figure 4 is a top view of the front support for the boiler;
Figure 5 is a front view of the same, with the sills A and the yoke plate M in
section; Figure 6 is an end view of the same with the axle in section; Figure 7 is
a cross section through line x, x, of Figure 1; Figure 8 is a side elevation of the
traction wheel with the axle and stationary boxes in section, and Figure 9 is a
central section of the wheel.
A, A, represents a pair of iron sills made in the form of channel bars, as shown
in Figures 2 and 5, and extending the full length of the engine from the front
truck to a point some distance in rear of the boiler. These two sills constitute the
main frame of the engine, and at the point where they extend beyond the rear of
the engine they form a support for the platform for the use of the driver and
fireman, and a support also for the water tank B which is suspended from the
underside of the same. These sills A, A, while constituting the main frame, are in
no wise bolted or rigidly attached to the boiler except at one point a, where they
are connected by angle irons on each side. There being but this one connection
with the sills it is obvious that the expansion and contraction of the boiler is in no
wise affected by the said sills. The boiler is supported at other points by a loop
or stirrup strap Chung to the sills in the rear, and by an expansion joint with
the front truck, as will be hereafter described. This stirrup or loop C carries the
principal part of the weight of the boiler, and relieves the sheets of the boiler from
all strain caused by carrying it in brackets or plates which are usually bolted to
the sheets; D, D, are metál side plates bolted to the iron sills on each side of the
boiler, and extending vertically therefrom. Each of these plates has a slot or notch
at its lower side which slips over the axle E to brace it, and has at the top two
levels, the lower one of which carries the bearings F for the countershaft, and the
upper one of which levels is bolted to the end of the engine frame G which carries
the crank shaft. This end of the engine frame is forined like a saddle, which
straddles the rear end of the boiler, but is not rigidly attached to it. The lower
sections of the two bearings F for the countershaft are formed in one piece, being
connected by a flanged and trough shaped bar F¹, which serves as a brace to connect
the two side plates firmly together, as in Figure 3. These side plates carry the
weight of the rear end of engine frame, crank shaft, flywheel, and pillow block,
and carry all the working strain, thus entirely relieving the boiler of the same.
The engine frame G, it will be seen, rests at its back end upon the top of the side

page_text: b
plates as before described, while at its forward end it rests upon the boiler. It is
not rigidly attached to the boiler at this point, however, but has an expansion
joint to prevent any strain occurring between the said frame and boiler, due to the
heating and cooling of the latter. This joint is shown in Figure 7, in which b is a
plate or casting rivetted to the boiler, and c are shouldered bolts which pass
through longitudinal slots in the flange of the engine frame, so that after the bolts
are tightly screwed down the engine frame still can slide longitudinally by reason
of its slots over the plate b to permit the expansion and contraction of the boiler
without strain, the plate 6 being provided with side flanges preferably to cooperate
with the shoulder bolts in preventing side movement. For steering the engine the
front axle H is arranged to turn about a vertical centre, and a chain is attached to
one side of the axle, and thence extends rearwardly to a roller or drum I, around
which it is passed several times, and is then returned to the axle on the other side
of its pivot, so that by revolving the drum one way or the other the chain is
wound up on one side and unwound on the other to change the position of the
front axle from a right angular position to an oblique one to cause the turning of
the engine. This drum I extends transversely across the machine beneath the
boiler, and it is carried by a hanger J bolted to the main sills A. For rotating this
drum a worn wheel d is arranged at one end, and a worm e made to gear there-
with, which worm is carried by a shaft K extending to the rear, and carrying a
hand wheel in convenient position for the driver.
This steering mechanism as so far described I do not claim as new. With such
a chain gear, however, I find that when the front truck axle is in the oblique
position, the chain does not equally wind up on one side and unwind upon the
other, and, furthermore, in running against obstacles it sometimes happens that
one front wheel will strike an obstruction and throw the axle around, leaving it in
the position which causes the engine to run out of its course, and involving also a
damaging strain upon the connection. For avoiding all these objections I place in
the length of the chain on each side and preferably near the axle an elastic spring f,
of either a spiral piece of metal or a block of rubber. This may be in the nature
of an elastic link in the chain as shown, or it may be a spring attached directly to
the axle on each side of its central pivot. This it will be seen allows the chain
to give and compensate for the unequal winding, and if one wheel strikes an
obstruction the spring relieves the gears of strain, and also immediately restores
the axle to its proper position.
For connecting the boiler to the front axle, a box plate L is employed having a
curved upper surface adapted to fit the bottom of the boiler, and which is slotted
lengthwise the boiler, as in Figure 4, and is connected to the boiler by shoulder
bolts m, which when screwed tight to the boiler allow the latter to move length-
wise of the plate to compensate for expansion. This box plate L is bolted between
the forward ends of the side sills A, A, and is connected with a yoke plate M. by a
vertical bolt n, about which the circular upper end of the yoke M turns after the
manner of a fifth wheel. This yoke plate receives a cap plate N, which passes.
through it and is fulcrumed to it by a bolt o. This cap plate has two chambers,
one upon each side of its fulcrum, in which are contained springs p, p, that bear
upon the axle of the front wheels. This axle H passes through the cap plate N,
and is provided with two clips q, q, which are rigidly connected with the axle, and
serve to hold the cap plate in proper position upon the axle; P is a brace which
extends from the bottom of the yoke plate M to the sills A, A, for the purpose of
resisting the strain involved in running against obstructions.
I will now describe the improved traction wheel. A² represents a spoked wheel
having a toothed or fluted tire for better engagement with the earth, and a hub a²
of large diameter. Within this hub is arranged a stationary box 62 having a
circular periphery, which with the inner surface of the hub forms the lubricated
joint of the wheel. This box 62 has in its middle a vertical chamber with straight
guide walls, within which is contained a smaller box c³ having a square horizontal
hole through it which receives the axle. Within this chamber and beneath the

page_text: box c² carrying the axle E are spiral springs d2, which form an elastic connection
between the load on the axle and wheel. The box b is held in the hub a² of the
wheel against slipping out laterally by a head plate e² on the outer end of the axle,
and a corresponding plate f2 at the opposite end, which latter is formed in one
piece with the inner box c³, the two plates e² and f* being fastened together by
bolts g².
B2 is a gear wheel attached concentrically to the side of the running wheel and
bearing teeth which mesh with the teeth of the driving wheels. This wheel B²
has a hub h that turns on a peripheral bearing of the plate f2, and it is attached
to the wheel A³ in a peculiar manner. Thus, to the side of the spokes of wheel A?
I attach strongly by bolts a circular band of metal C2 carrying lugs 2, while upon
the arms or web portion of wheel B2 are formed other lugs 72. These sets of lugs i²
and I then connect by spiral springs D2, which have the following important
functions. The gear wheel, it will be seen, must from the necessity of the case be
immovable with respect to the driving gears with which it meshes and by which
it is driven. Now the result sought by me is to get a traction wheel (which has
the function of a driver as well as that of a passive running wheel) which will
always be in gear with the driving wheels and yet be permitted to vibrate in right
lines as it passes over rough ground, or in other words a traction wheel which is
not necessarily concentric with its axle. This result is attained by the springs D³,
for although the gear wheel is always rigid and immovable the running wheel
vibrates in its plane with a universal spring connection capable of oscillation
throughout the 360° of the circle and producing varying strains on the springs,
sometimes end wise and sometimes sideways, sometimes a tension and sometimes a
compression. It is this connection of the gear wheel and running wheel which
makes a spring seated axle possible in the hub of a traction wheel, for without
this said connection the running wheel could not be an active or propelling wheel
without having its centre concentric with its axle and a constant distance from the
centre of the gear wheel which drives it. Incidentally these springs D³ also cause.
the rotary strain on the running wheel to be a yielding one.
Now in defining the Invention more clearly, I would state that I am aware that
a spring has been arranged between a gear wheel and the shaft of a road engine
for the purpose of making the rotary strain a yielding one, and I do not claim this,
but I do not know that a separate driving gear wheel has ever been combined with
a traction wheel (or a wheel which is both a runner and a driver) by a spring
connection which permits the runner to vibrate iu right lines in all directions in
its plane, and this I claim. I am also aware that a vehicle wheel which simply
runs without propelling has had an axle with a subjacent spring contained in a
hollow box around which the hub revolves, and I only claim the additional box c²
in this connection, which gives a larger and stronger bearing and a firmer sliding
connection between the axle and main box. This box c³ may also be taken out
when worn and replaced by another with much less expense than would be incurred
by a renewal of the axle.
Having described the nature of the said Invention, and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
herein before in part recited Letters Patent is,―
1st. The side sills A, A, made longer than the boiler and combined with the
same by strap C and a single rigid connection a, and extending in rear of the
boiler, substantially as and for the purpose described.
2nd. The combination with the axle E and the engine frame G connecting and
supporting both the main shaft and cylinder of the side plates D arranged to
support the rear end of the engine frame and carry the weight and strain of
the working parts of the engine and relieve the boiler, substantially as
described.
3rd. The combination with the boiler and the axle E of the side plates D and
the engine frame G resting at one end upon the side plates and at the other

page_text: connected to and resting upon the boiler through an expansion joint, as
described.
4th. The combination with the boiler of the sills A connected to and sustaining
the rear end of the same by a strap C and connected to the boiler at their front
ends by an expansion joint, as described.
5th. The combination in a road engine with a pivoted front axle and the
chain gear of a spring connection for said chain, as and for the purpose
described.
6th. The combination of the axle H, spring seated cap N, the yoke plate M, and
the box plate L, the box plate and yoke plate being connected by a vertical pivot
bolt, and the yoke plate and cap plate being connected by a horizontal fulcrum
bolt, substantially as described.
.
7th. The combination with a driving or gear wheel of a parallel running wheel,
having also the function of a driver or propeller and connected to the gear wheel
by springs for right line oscillation in every direction lying within its plane, as
described.
8th. In a wheel having its axle spring seated within its hub, the combination
with the hub and a hollow non-rotating box therein of a removable box c³ carrying
the axle and fitting snugly within the main box and one or more springs located
beneath the said box c and between the same and the main box, as shown and
described.
9th. A traction wheel having a spring connection between the axle and the hub
combined with a gear or driving wheel and connected to it by springs as described
for oscillation in right lines in every direction lying within its plane, as and for the
purpose described.
10th. A traction wheel composed of a running wheel and a gear wheel applied
to each other and connected by springs, as described, combined with the axle, and
a spring seated box carrying the axle located within the hub of the running wheel,
as shown and described.
11th. The combination of wheel A³ having hub a², box b², spring seated box c³,
the heads e and f2, and the wheel B2, arranged to revolve upon the peripheral
portion of head f, and flexibly connected with A, as described.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Sixth day of October, A.D. 1881.