Improvements in Traction and similar Self-moving Engines..
Year: 1886

page_text: Date of Application, 15th Dec., 1886
Complete Left, 15th Sept., 1887
Complete Accepted, 18th Oct., 1887
PROVISIONAL SPECIFICATION.
Improvements in Traction and similar Self-moving Engines..
I THOMAS COOPER of Great Ryburgh in the County of Norfolk, Engineer do
hereby declare the nature of this invention to be as follows:-
:-
The object of this invention is to cheapen and simplify the construction of traction
engines for agricultural purposes, and render them more durable than heretofore.
This I propose to effect first by reducing the number of wearing parts, in connection
with the driving gear, and secondly by improving the means for reversing the engine,
the reversing gear being at present a fruitful source of injury and damage to the parts.
Hitherto traction engines have generally been constructed with single cylinders, this
construction being a more economical arrangement than a pair.
In engines thus constructed, the power of the cylinders is found either too great
when the engine is travelling on good roads or too little when going over soft ground,
consequently gearing has to be provided between the crank shaft and road wheels, so
as to give more than one speed, a fast speed being used for ordinary travelling, and a
slower speed when the engine is going over heavy ground, and therefore requiring
more power for propulsion.
Now in order to simplify the construction of the engine, and still retain a great
variation in the power, I do away with the second speed in the gearing usually
provided, and use only one speed in conjunction with a compound engine, and I
employ a device by which the engine can (at will) be converted from a compound to a
coupled or double cylinder high pressure engine, for the purpose of gaining the extra
power required, say to travel over a piece of very soft ground, up a steep hill, or
the like.
The compound engine I employ is a high pressure engine having two cylinders, one
of larger diameter than the other. In ordinary work, steam is admitted from the
boiler to the small cylinder only, the exhaust steam from which is passed to the large
cylinder, and thence to a condenser or the atmosphere. By admitting live steam into
he large cylinder direct, and giving a free exhaust to the small cylinder, the ordinary
power of the engine will be more than doubled. The cranks for the two cylinders are
set at right angles to each other, so that there are no dead centres. In order to easily

page_text: convert the compound into a high pressure engine, the starting valve and ports are
constructed in such a way that when a handle is moved one way, the valve admits
steam to the small cylinder and exhausts from it to the large cylinder, but when the
handle is moved the reverse way, the valve admits steam to both cylinders, and allows
the exhaust steam to pass away from the small cylinder in the same manner as the
large one.
now come to the second head of my invention:-In traction engines as generally
constructed, a link motion or other reversing gear is employed, whereby it is possible
for the valves to be reversed while the engine is running. This motion, besides being
in itself costly to keep in order, is frequently, in the hands of inexperienced men, the
cause of serious breakages, as an engine being suddenly reversed, throws great strain
on the various parts. In engines as usually made, a reversing motion, which can be
operated while crank shaft is moving, is almost a necessity, in order to get over the
dead centres, but in a compound engine as above described, such reversing motion is
not necessary, as there are no dead centres the cranks of the cylinders being set at
right angles to one another. In place of the reversing motions now employed, I use
a single excentric mounted on the crank shaft, so that it can be turned on the shaft
part of a revolution to drive each slide valve (one to each cylinder). In each excentric
is a slot or its equivalent, and on the crank shaft are mounted firmly two stops or their
equivalent, in such a manner that when one end of the slot in the excentric is against
the stop, it is in right position for running forward, and when turned round on the
shaft, so that the other end of the slot is against the stop, it is in right position for
running backwards.
From a perusal of the above description, it will be seen, that traction engines
constructed according to my invention will have but few parts to get out of order, but
will still retain the efficiency of engines hitherto constructed. Further, the reduction
in the number of the wearing parts will lessen the weight of the whole engine, and
consequently will allow of an economy in steam required for propulsion where such
economy is of importance, and where weight is not an object, as it is in the case of
steam rollers.
1000

page_text: COMPLETE SPECIFICATION.
Improvements in Traction and similar Self-moving Engines.
I THOMAS COOPER of Great Ryburgh, in the County of Norfolk, Engineer, do
hereby declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
The object of the present invention is to cheapen and simplify the construction of
traction and similar self-moving engines for agricultural purposes.
In Agricultural self-moving Engines as usually constructed, is customary to
provide gearing between the crank shaft and road wheels capable of giving two
speeds, a fast speed for ordinary purposes, and a slower speed for use when more
power is required, as for instance when it is desired to mount a hill, or to traverse soft
and heavy ground.
My invention relates to improvements by which I am enabled to dispense with the
second speed, and to provide at the same time for the variation in power necessary
under different conditions.
My invention relates further to improvements in the reversing gear,
which is a
common source of trouble in ordinary engines, on account of the breakages which
are liable to take place when the engine is reversed too suddenly.
In carrying out my invention, I employ a compound engine consisting of two
cylinders, a small one and a larger one, into which the former exhausts, and I
employ an arrangement of parts and valves by means of which live steam may be
admitted into both cylinders simultaneously, and the compound engine readily
converted into a coupled or double cylinder high pressure engine for the purpose of
giving them the extra power required for mounting a hill or traversing heavy ground.
With this arrangement, one speed only will be required, and the additional gearing
usually employed may therefore be dispensed with, and thereby considerable saving
in the cost of construction, as well as in the weight of the engine, may be effected.
My arrangement for reversing the engine consists in the adaptation of a well
known device in which a pair of excentrics are mounted on the crank shaft, and
are capable of being partly. rotated thereon. The slide valves of the engine are
operated from these excentrics, so that the turning of the excentrics upon the
crank shaft from one extreme position to the other, will reverse the position of the
valves and the direction of the engine.
The means I prefer to employ for shifting the excentrics I will hereafter fully
describe.
I will now proceed to describe my invention more fully, with reference to the
accompanying drawings.
Fig. 1 is a general view of a Traction Engine in side elevation with my invention
applied thereto.
Fig. 2 is a plan of the same.
Fig. 3 is a horizontal section of the cylinders on a larger scale.
Bio is a vortioal senfion on the line of Fio. 3.

page_text: Fig. 5 is a side view of the cylinders with the cover of the starting slide steam
chest removed, and
Fig. 6 is a sectional view on the line y y of Fig. 4.
Figs. 7, 8 and
several positions.
are diagram views shewing in section the starting slide in its
5
Fig. 10 is a face view of the starting slide in the position of Fig. 7.
Fig. 11 is a face view of the slide in the position of Fig. 9; and
Fig. 12 is a transverse section of the slide.
Figs. 13, 14, 15 and 16 are detail views shewing the reversing gear and mode of
operating the same.
A and B are the cylinders situated upon the boiler of the engine, and formed in one
casting with various ports, passages, and steam chests to be presently described. A is
a smaller cylinder than B, and for ordinary work is used as a high pressure cylinder
exhausting into the larger low pressure cylinder B.
C is a steam chest, in which is situated the starting valve C*, and c is the starting
valve rod operated by the hand lever c¹.
D D' are the slide valves of the cylinders A and B respectively, and d d¹ are their
rods operated from the excentrics E É upon the crank shaft F.
The engine is provided with a simple driving chain between the driving pinion on
the crank shaft and the road wheels, but any other ordinary single speed gearing may
be employed. Means are provided for disconnecting the gear between the road wheels
and crank shaft when the engine is wanted for stationary purposes.
The steering gear may be of ordinary construction, and, with some other parts
which are not shewn, or only indicated in the drawings, does not need description.
Steam is admitted from the boiler through the pipe G (see Fig. 4) to the starting
slide steam chest C. Within the steam chest C are four ports, shewn most plainly in
Figs. 7, 8, and 9; one leads to the steam chest a of the small, or high pressure
cylinder A; one to the steam chest of the larger or low pressure cylinder B; the
third is the exhaust from the high pressure cylinder A; and the fourth is a port
leading to the atmosphere direct. The third and fourth ports lie always beneath the
slide *, and in one of its positions are connected together through the slide, while in
another position the 3rd and 2nd ports are so connected, and the 4th is closed.
When the cylinders are arranged as a compound engine, the starting slide is in the
position shown at Fig. 9; the 1st port is then open, the 2nd and 3rd connected through
the slide C, and the 4th closed. The course of the steam is indicated in Fig. 3.
Entering the 1st port, it traverses, in the direction of the arrows, the passage leading
to the steam chest a, in which are situated the high pressure cylinder ports and slide
valve D.
In Fig. 3 I have indicated with arrows the steam entering one of these ports e, and
exhausting through the other e¹. The port e¹ is in connection, through the slide
valve D, with the exhaust port d* in the cylinder casting. This port d* leads direct
to the 3rd port of the steam chest C, which is connected by the slide C with the
2nd port. Through this the steam passes, and along the passage 6* in the cylinder
casting, to the steam chest b, in which is the slide D and ports 6 and 62 of the
cylinder B.
In Fig. 3 I have indicated the exhaust steam from the cylinder A entering the
cylinder B through the port ', the exhaust being in the direction of the arrows through
the other port, to the passage 63, which leads direct to the chimney (see Figs. 1 and 2).
To convert the engine from a compound into a coupled or double cylinder high
pressure engine, the hand lever c¹ is pulled ever into the position marked 1 in Fig. 2
of the drawings, and the slide C* thereby moved to the position shewn in Fig. 7, in
which both the 1st and 2nd ports are partially open, and live steam is admitted from
the steam chest C into both the cylinders A and B direct. The exhaust from the
cylinder A takes place through the 3rd and 4th ports connected by the slide C* to the
chimney, and from the cylinder B through the passage 63 as already described.
Fig. 8 shows the position of the slide C when the engine is in a state of rest; the
hand lever c is then in the central position shown in Fig. 2.

page_text: To reverse the engine, I employ the arrangement shewn detached, and in detail, at
Figs. 13 to 16 of the drawings.
EE are a pair of excentrics, preferably cast together, mounted loosely upon the
crank shaft F, and embraced by the bands upon the ends of the rods d d' of the slide
valves D D. Keyed fast upon the shaft F is a disc or sheave H having a segmental
sloth therein, with rack teeth upon its inner side (see Fig. 16). Within the slot, and
in gear with the rack teeth therein, lies the pinion head of the spindle I, which
passes through both excentrics along side the crank shaft (see Fig. 14), and is screwed
for the remainder of its length in the manner shewn.
It will thus be seen that the excentrics E E are keyed to the crank shaft F through
the spindle 1 and fixed disc H, but are capable of an independent rotation thereon,
limited by the traverse of the pinion within the slot h.
The
Loose upon the crank shaft F is a sleeve K, wherein is a threaded hole k fitting the
thread of the screwed spindle I. The sleeve K is capable of being slidden endwise
upon the crank shaft F by means of the jaws 7 of the lever L pivotted to the framing
of the engine, so as to rotate the spindle I in one direction or the other.
rotation of this spindle causes the rack teeth in the slot h of the fixed disc H to operate
upon the pinion i before named, and work the same from one end of the slot to the
other, turning at the same time the excentrics E E and sleeve K upon the crank shaft.
The shifting of the excentrics changes, through their rods d d¹, the positions of the
slide valves D D¹, and reverses the engine in the usual manner.
Thus it will be seen
that when the engine is at work, the excentrics E E and slide valves D D' are driven
by the disc H fixed to the crank shaft, one end of the sloth bearing against the
pinion; and, when the engine has been stopped, and it is desired to re-start it in the
opposite direction, the independent movement of the excentrics upon the crank shaft
will enable the position of the slide valves to be reversed.
It should be here remarked that inasmuch as it is of the highest importance, to avoid
accidents at the hands of an ignorant driver, that the reversal of the engine should be
next to impossible except at a state of rest, the pitch of the screw of the spindle I
should be such as to practically preclude the possibility of turning the excentrics while
pressure of steam is upon the slide valves D D. The pitch should, however, be
sufficiently quick to allow of the pinion i traversing its course without too great a slide
of the sleeve K.
It is evident that if the steam be cut off and the engine brought to a standstill
before any attempt is made to reverse, which will always be the case with my arrange-
ment, a great danger of breaking and straining the parts will be avoided.
I have described and shewn the means I prefer to adopt for shifting the position of
the excentrics upon the crank shaft, but it is obvious that other means may be devised
to accomplish this object.
Having now particularly described and ascertained the nature of my said Invention
and in what manner the same is to be performed, I declare that what I claim is :-
1. In Traction and similar self-moving Agricultural Engines, the method herein
before described, of increasing the effective power of the engine at the option of the
driver, without the employment of gearing to give more than one ratio of speed
between the crank shaft and road wheels.
2. Reversing Traction and similar self moving Agricultural Engines constructed on
the compound principle, by moving the valve excentrics round upon the crank shaft in
the direction of its last rotation.
התנג
TELL
2
1000
NEWTON & SON,
Agents for the Applicant.