IMPROVEMENTS IN LOCOMOTIVE ENGINES FOR RAILWAYS, TRAMWAYS, AND ROADS."
Year: 1880

page_text: LETTERS PATENT to Thomas Hunt, of Manchester, in the County of Lancaster,
for an Invention of "IMPROVEMENTS IN LOCOMOTIVE ENGINES FOR RAILWAYS,
TRAMWAYS, AND ROADS."
PROVISIONAL SPECIFICATION left by the said Thomas Hunt at the Office
of the Commissioners of Patents on the 27th August 1880.
THOMAS HUNT, of Manchester, in the County of Lancaster.
LOCOMOTIVE ENGINES FOR RAILWAYS, TRAMWAYS, AND ROADS."
"IMPROVEMENTS IN
My Invention consists in mounting the wheels, or only one wheel, loose upon
one or more of the carrying axles of the engine, and employing an intermediate
wheel between one or more of the carrying wheels and one or more of the driving
wheels, to which intermediate wheel or wheels an adjustable arrangement is
attached, by which, when requisite, one or more can be separately or simultaneously
forced in contact with the peripheries of their respective driving and carrying
wheels, and thus by frictional pressure prevent the driving wheels from slipping on
the rails, and at the same time enable the engine to pass more freely through curves
than if all the wheels of the carrying axles were fixed upon their axles, or than if
the driving and other axles were coupled together by the rigid connection of
coupling rods and cranks.
I also propose to utilize the intermediate wheel or wheels as a brake when
passing down steep gradients, or for ordinary purposes by reversing the engine and
applying the steam in the opposite direction, and thus causing the driving wheels
to slip on the rails and drive the intermediate wheel or wheels along with the
carrying wheel or wheels with which they are in contact.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent_filed by
the said Thomas Hunt in the Great Seal Patent Office on the 26th February
1881.
"IMPROVEMENTS IN
THOMAS HUNT, of Manchester, in the County of Lancaster.
LOCOMOTIVE ENGINES FOR RAILWAYS, TRAMWAYS, AND ROADS."
My said Invention, which relates to improvements in locomotive engines for
railways, tramways, and roads, has for its essential objects enabling such engines
to pass freely around curves and to increase the efficiency of their wheel power.
My improvements consist in mounting one or more of the wheels of the engine
loose upon one or more of the carrying axles, and providing an intermediate wheel
between each loose wheel and the driving wheel on the same side of the engine,
and in providing a corresponding intermediate wheel or wheels at the other side
of the engine, between the fixed wheel or wheels and the driving wheel. To tho
said intermediate wheels an adjustable arrangement is attached, by which, when
necessary, one or more of the said wheels can be separately or simultaneously 1
forced in contact with the peripheries of their respective carrying and driving
wheels, and thus by frictional pressure prevent the driving wheels from slipping on
the rails, and at the same time enable the engine to pass more freely through
curves than if both the wheels of the carrying axle were fixed upon the axle, or
than if the driving and carrying axles were coupled together by the rigid connection
of coupling rods and cranks.
And in order that my said Invention may be fully understood, I shall now
proceed more particularly to describe the same, and for that purpose shall refer to
the several Figures on the annexed Sheet of Drawings, the same letters of reference
indicating corresponding parts in all the Figures.
Figure 1 of the accompanying Sheet of Drawings represents in sectional side
elevation a locomotive engine with my said Invention applied thereto.
Figure 2 is a sectional plan of the same.
Figure 3 is a sectional end elevation, the view being taken in the direction of the
smoke box end of Figure 1.
Figure 4 is a sectional end elevation, the view being taken in the direction of
the fire box end of the same Figure.
Figure 5 illustrates the application of the Invention to a road engine.
The following alphabetical list refers to the several letters marked upon the
accompanying Drawings, and indicates all the parts of the engine :-
A is the right hand intermediate shaft and levers.

page_text: the intermediate wheel or wheels over the outer wall of the curve to bear upon its
carrying and driving wheels on that side of the engine. The engine is enabled to
turn with great facility in the required direction.
Either one of the wheels upon the axle A¹, or other axle, may be so mounted
loose, and either one or both of the intermediate wheels may be brought into
operation according as it is required to turn in one direction or the other, or to
follow a straight course.
In addition to these advantages any surplus power given to the driving
wheels Z, which would under ordinary circumstances be expended by reason of the
said wheels slipping on the rails, is imparted to the intermediate wheels and
communicated to the leading wheels of the engine, so that tractive power is thus
gained.
In order to admit of the intermediate wheels being either separately or simul-
taneously brought into action according to the necessities of the case, the said
wheels are mounted independently of each other and provided with separate steam
cocks, as herein before described.
The said wheels are preferably grooved upon their peripheries so as to correspond
with the flanges of the leading and driving wheels, as shewn in the Drawings.
A further application of my said Invention consists in the use of the intermediate
wheels as brakes upon the leading and driving wheels of the engine when passing
down steep gradients, or for ordinary purposes by reversing the engine and
applying the steam on the opposite direction, and thus causing the driving wheels
to slip in the rails and drive the intermediate wheels so as to communicato a
reverse motion to the leading wheels or other wheels with which the intermediate
wheels are in contact.
In lieu of bringing both intermediate wheels into operation to act as brakes
one only may be employed, and at either side of the engine.
In the plan, Figure 5, an intermediate wheel O' is shewn applied to the leading
and driving wheels N¹, P¹, respectively of a road locomotive engine, the leading
wheel N being mounted loose upon its axle. The wheels of the traction engine
having their peripheries plain, the periphery of the intermediate wheel O¹ is also
so constructed, as shewn."
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried into effect,
I would observe in conclusion that what I consider to be novel and original, and
therefore claim as the Invention secured to me by the hereinbefore in part recited
Letters Patent is,―
In locomotive engines for railways, tramways, and roads, mounting one or more
of the wheels loose upon one or more of the carrying axles of the engine, and the
other wheel fast upon the said axle or axles, and employing in combination
therewith intermediate friction wheels between the said loose and fixed wheels and
the driving wheels, substantially as and for the purposes hereinbefore described.
In witness whereof, I, the said Thomas Hunt, have to this my Specification
set my hand and seal, this Twenty fourth day of February, One thousand
eight hundred and eighty one.