IMPROVEMENTS IN THE CONSTRUCTION OF SELF-PROPELLING OR LOCOMOTIVE ENGINES
Year: 1877

page_text: LETTERS PATENT to Robert Edwards, of Thetford, in the County of Norfolk,
Engineer, for the Invention of "IMPROVEMENTS IN THE CONSTRUCTION OF
SELF-PROPELLING OR LOCOMOTIVE ENGINES."
Sealed the 14th August 1877, and dated the 25th May 1877.
2
PROVISIONAL SPECIFICATION left by the said Robert Edwards at the
Office of the Commissioners of Patents on the 25th May 1877.
ROBERT EDWARDS, of Thetford, in the County of Norfolk, Engineer. " IMPROVE-
MENTS IN THE CONSTRUCTION OF SELF-PROPELLING OR LOCOMOTIVE ENGINES."
This Invention relates, firstly, to means for driving the travelling wheels of
engines which are fitted with bearing springs, for easing the motion of such engines.
over rough or uneven ground.
The difficulty to be overcome is, as is well known, to compensate for the variable,
distance between the axis of the travelling wheel axle and the centre of motion of
the power transmitting gear wheel.
I now propose to fit, say, the discs or pulleys of each travelling wheel, or a single
disc or pulley attached to the axle or the centre or driving disc of differential'
motion or compensating gear (as usually arranged on the axle), with a ring of
laterally projecting pins or projections (such pins or projections. being set generally.
at equal distances apart), and to form in the power-transmitting wheel or wheels
recesses or openings to receive the pins, such recesses or openings being made,
sufficiently large to compensate for the extreme vertical play of of the bearing,
springs.
The wheel or wheels having the ring of openings or recesses are driven from the,
countershaft, and are mounted loosely on a hollow bracket or sleeve made fast to
the engine boiler or frame, and through it or them passes the axle of the travelling
wheels, but excentrically thereto. Sometimes, however, they may be keyed' to a'
hollow rotating shaft. This excentric arrangement provides for the side of one or
more of the recesses or openings in the power-transmitting wheels bearing against
one or more of the pins on the wheel or axle discs or pulleys, no matter how inuch

page_text: the relative positions vertically of those wheels and the travelling axle may vary
owing to the yield of the bearing springs.
It will be obvious that the wheels may carry the pins, and the wheel, or axle
discs, or pulleys, or their equivalent, may be slotted to receive the pins, which will
in this case be driving pins.
The same arrangement can also be fitted round the countershaft instead of the
driving wheels and their axle. In this case, however, the countershaft is arranged
in a frame with the axle, and rises or falls with it with the action of the bearing
springs.
My Invention relates, secondly, to the driving of the travelling wheels of
agricultural and other engines, when the driving shaft receives its motion direct
through cranks and connecting rods. To facilitate the turning of the engine at the
land's end and elsewhere I mount the wheels loosely on the driving axle, and
connect their hubs, by means of sleeve shafts, with a pair of discs cast with bevil
or spur teeth and forming part of an arrangement of differential gear. Between
these discs is a central wheel which is keyed to the driving axle, and carries at its
periphery a pair of pinions. These pinions are mounted loosely on stud axles, and
take into the teeth of the discs. When therefore the engine is required to run in
a direct line the travelling wheels will be driven through the differential gearing
at equal speeds, but on steering the engine to the right or left the progress of the
fulcrum wheel will be arrested or retarded, the differential gearing providing for
this while the speed of driving of the other wheel is maintained.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Robert Edwards in the Great Seal Patent Office on the 24th
November 1877.
ROBERT EDWARDS, of Thetford, in the County of Norfolk, Engineer. "IMPROVE-
MENTS IN THE CONSTRUCTION OF SELF-PROPELLING OR LOCOMOTIVE ENGINES."
•
This Invention relates, firstly, to means for driving the travelling wheels of
engines when such engines are fitted with bearing springs, to ease their motion over
rough or uneven ground.
The difficulty to be overcome is, as is well known, to compensate for the variable
distance between the axis of the, travelling wheel axle and the centre of motion of
the power-transmitting gear wheel.
I now propose to key to the axle of the travelling wheel a disc, fitted with a
ring of laterally projecting pins (such pins being set at equal distances apart), and
to form in the power-transmitting wheel recesses or openings to receive the pins,
such recesses or openings being made sufficiently large to compensate for the
extreme vertical play of the bearing springs.
The wheel having the ring of openings or recesses is driven from the counter-
shaft, and is mounted loosely on a hollow bracket or sleeve made fast to the engine
boiler or frame, and through it passes the axle of the travelling wheels, but
excentrically thereto..
When compensating gear is used on the main axle it is driven by the pin and
slot arrangement of gear, as above described.
When it is desired to drive both the travelling wheels directly I duplicate the
:

page_text: driving gear, arranging it at opposite sides of the engine, and in this case the main
spur wheels will receive respectively their motion from pinions on the countershaft.
It might be desirable sometimes, however, to dispense with the arrangements on
the main axle, and place them on the countershaft, and connect the main axle and
countershaft together, so that they rise and fall together with the action of the
springs.
The second part of my Invention relates to locomotive engines which have the
power communicated to their driving wheels by outside connecting rods or coupling
rods, and to facilitate and allow the driving wheels to move independently of each
other on curved or crooked roads I arrange compensating gear on the axle either
between the wheels or outside one of them, the centre or driving disc of such
compensating gear being keyed to the axle.
It is obvious that such an engine could have springs applied to it to carry the
engine, the coupling or connecting rods allowing for their action.
C
In the accompanying Drawing Fig. 1 represents in transverse, sectional elevation
the simplest form of engine, in which A is the driving axle, and B, B', the driving
wheels mounted loosely thereon; C is a driving disc keyed on the axle A, and
furnished with a series of pins which take into radial slots d in a spur wheel D.
This wheel D is mounted on a sleeve E attached to the main frame F of the engine,
and it receives motion from a spur pinion on a countershaft.
The travelling
wheel B is connected to the driving disc C by a locking pin, which is inserted in
holes b made to receive it, and the wheel B¹ is similarly locked to a brake pulley G,
which is keyed to the axle A.
Through the sleeve E the axle A passes excentrically, and the weight of the
engine is brought upon the axle through the intervention of springs H, which rest
upon the axle boxes that slide in guides in the framing.
Through the excentricity of the axle A, in respect to the sleeve E, the pins c in
the driving disc receive the transmitted driving power more or less in a horizontal
direction. This will be better understood by reference to the Diagram Fig. 2,
which shews the excentricity of the driving disc C as compared with the spur
wheel D. In this Figure it will also be seen that the slots d, which receive the
pins c, are wide and deep enough to allow the axle A and the driving disc C on it,
and its series of pins, to rise and fall with the action of the bearing springs H.
Fig. 3 is a modification of Fig. 1, shewing compensating or differential gear
arranged upon the driving axle A. In this arrangement the motion imparted to
the driving disc C is transmitted through bevil pinions C₁ (mounted on radial studs
carried by the disc) to a face wheel A¹, keyed on the axle A and to a ring of
teeth B*, made fast to the hub of the travelling wheel B. The boss of the travelling
wheel B' is cast in one piece with or firmly secured to the brake pulley G, which
is keyed as in the first arrangement to the axle A.
Fig. 4 represents a double arrangement of driving discs C and spur wheels D,
each spur wheel being driven by an independent pinion D*, which are compensated
in respect to each other by an arrangement of compensating gear on the counter-
shaft. Thus the travelling wheels B, B¹, will be free to answer to the motions of
the steering wheel as in the former arrangements.
The second part of the Invention is illustrated in transverse section at Fig. 5,
which represents an engine with outside cranks keyed on the main axle A, to
which power is transmitted through coupling rods connected with the cranks. On
one end of the axle A is keyed a driving disc I, carrying a crank pin i, and on the
opposite end of the axle A is keyed the crank I*. Mounted on the disc I are the
bevil pinions K, which take into face wheels L, M, the former of which is made
fast to the nave of the travelling wheel B, while the latter is secured to a sleeve
shaft N to which the travelling wheel B₁ is keyed. By this arrangement it will
be seen that the travelling wheels can be driven, when desired, at differential speeds.
Springs H are arranged above the axle which runs in axle boxes O, as in the former
arrangements.
A series of pairs of wheels can be worked differentially through the above

page_text: compensating gear arranged, their cranks being coupled together by coupling rods,
as desired.
Having now set forth the nature of my Invention of "Improvements in the
Construction of Self-propelling or Locomotive Engines," and explained the manner
of carrying the same into effect, I wish it to be understood, that under the above
in part recited Letters Patent I claim,-
First. In respect of locomotive engines which are driven by gear wheels, the
means above described for compensating for the varying distance between the axis
of the travelling wheels and the axis of the main gear wheel or wheels when
bearing springs are employed.
Secondly. In respect of locomotive engines, the main axle of which receives its
motion from outside cranks and coupling or connecting rods, applying compensation
gear thereto for the purpose of driving the travelling wheels in the manner above
described.
"
In witness whereof, I, the said Robert Edwards, have hereunto set my hand
and seal, the Twenty-first day of November, in the year of our Lord One
thousand eight hundred and seventy-seven.