IMPROVEMENTS IN TRACTION ENGINES FOR TRAM OR OTHER ROADS
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by the said William Wilkinson at the
office of the Commissioners of Patents on the 28th November 1883.
WILLIAM WILKINSON, of Wigan, in the County of Lancaster, Engineer,
IMPROVEMENTS IN TRACTION ENGINES FOR TRAM OR OTHER ROADS
"
My invention relates to an improved traction engine without visible or audible
emission of steam, capable of being driven in either direction; and whose driving
connections permit of driving on steep gradients without danger of running away,
prevent the slipping of wheels on the rails, and make a more noiseless gearing
than spur wheels; and whose steam generation shall be economical and effective,
and at the same time within small compass.
These advantages I obtain by a novel combination of devices,
My invention relates specifically to improvements:
In the driving connections generally for alternative backward or forward driving
and compensation of wear.
.
In the Steam boiler.
In Superheating devices.
Firstly, as regards the driving connections :—
Upon the driving wheel axle I fit or form a worm wheel, and on the engine
crank shaft (conveniently driven directly from vertical, diagonal, or horizontal
cylinders) a worm or screw of a suitable pitch and number of threads proportioned
to the required power and speed. Or the positions of the wheel and the worm
may be varied. The wheel and the worm engage or gear with one another, and
the depth of the teeth and the worm threads is proportioned to the amount of play
required by the bearing springs of the engine.
On one end of the crank shaft are a series of collars rigid therewith or loose
thereupon. These collars are divided into two groups, each group provided with
a separate thrust bearing. These two thrust bearings are each adjustable by
means of screws or wedges, so as to be moveable in opposite directions, in order to
D
.
Firstly, as regards the driving connections :-
Upon the driving wheel axle I fit or form a worm wheel, and on the engine
crank shaft (conveniently driven directly from vertical, diagonal, or horizontal
cylinders) a worm or screw of a suitable pitch and number of threads proportioned
to the required power and speed. Or the positions of the wheel and the worm
may be varied. The wheel and the worm engage or gear with one another, and
the depth of the teeth and the worm threads is proportioned to the amount of play
required by the bearing springs of the engine.
On one end of the crank shaft are a series of collars rigid therewith or loose
thereupon. These collars are divided into two groups, each group provided with
a separate thrust bearing. These two thrust bearings are each adjustable by
means of screws or wedges, so as to be moveable in opposite directions, in order to
D

page_text: take up and compensate for any endwise play resulting from wear of the collars
or bearings, thereby keeping the engine cranks in true position with the centre line
of the engines and cylinders.
Secondly, as regards the boiler:-
I construct my boiler of the locomotive type with the ordinary fire-box, but
modified as follows:-
Between each two stay girders on the fire box crown or roof I suspend a number
of "Field " tubes of suitable length vertically over the fire-bars.
I make the boiler tubes in the form of a reverse curve, to compensate for extreme
expansion or contraction, thereby obviating risk of leakage at the tube plates-so
great in short tubed multitubular boilers.
I make the barrel or horizontal portion of the boiler, and in consequence the
tubes aforesaid, short, say conveniently the length equal to one third the diameter.
This short construction enables me to utilize very fully the heated gases and flame
from the fire box in superheating the exhaust steam.
Thirdly, as regards the superheater subjected to the heated gases and flame
aforesaid
-
Between two plates forming a chamber, I fit tubes of suitable diameter,
corresponding in position and coincident, centre to centre, with the boiler tubes,
and this chamber I fix in the smoke box against or near the boiler tube plate, so
that the bot gases and flames shall pass through the said tubes on the way to the
chimney, and shall superheat the chamber, which is fitted with a suitable blast
nozzle discharging into the funnel or chimney. Into this chamber for the purpose
of superheating and rendering same invisible, I lead the exhaust steam from the
engines and the waste steam from the safety valve, through suitable pipes, inter-
posing suitable expansion chambers and drain pipes to intercept and lead off any
condensed steam.
Alternatively, I may construct my superheating chamber in the form of a helical
coil of piping or pipes, placed and connected as aforesaid.
My said specified devices I employ conjointly with the other several parts
constituting a traction engine, but which, as my improvements do not moro
particularly relate to them, I do not now specify

page_text: In order that my invention may be the better understood, I now proceed to
describe the same with regard to the drawings hereunto annexed and to the
letters and figures marked thereupon.
Figure 1 shows a traction engine in sectional elevation embodying all my said
improvements.
Figures 2.3 and 4 show details of the superheating device
Firstly, as regards the driving connections-Upon the driving wheel axle A
I fit or form a worm wheel A¹, and on the crank shaft (conveniently driven from
vertical diagonal or horizontal cylinders) a worm or screw B. of suitable pitch and
number of threads proportionate to the required power and speed; or the positions,
of the worm and the wheel may be varied. The wheel A¹ and the worm B engage
with one another, and the depth of the teeth and worm threads is proportionate
to the amount of play required by the bearing springs of the engine-On one end.
of the crank shaft are a series of collars C. D. rigid therewith or loose thereupon.
These collars are divided into two groups C. and D, each group provided with a
thrust bearing. These two thrust bearings are each adjustable by means of screws
or wedges E, so as not to be moveable in opposite directions, in order to take up
or compensate for any endwise play resulting from the wear of the collars or
bearings, thereby keeping the cranks in true position with the centre line of the
engine and cylinders.
Secondly as regards the boiler :-
I construct my boiler of the locomotive type with the ordinary firebox, but
modify it as follows:-
Between each two stay girders on the firebox crown or roof I suspend a number
of "Field " tubes T (Figures 1 and 3) of suitable length vertically over the fire
bars I make the boiler tubes R in the form of a reverse curve to compensate for
extreme contraction or expansion, thereby obviating the risk of leaking at the tube
plates, so great in short multitubular boilers. I am enabled to make the barrel or
horizontal portion of the boiler short, say conveniently of a length equal to one
third the diameter, in consequence of the accumulated heating surface of the
hanging tubes aforesaid, and the elasticity of the reverse curved boiler tubes
aforesaid This short construction enables me to utilize very fully the hot gases
and flames from the firebox in superheating the exhaust steam.
Thirdly as regards the superheater subject to the heated gases and flame
aforesaid :-
Between two plates joined in any suitable manner, such as by casting, welding,
brazing, or rivetting, I form a chamber F, and in this chamber I fit tubing of

page_text: suitable diameter S, corresponding in position, and coincidentally set to the centre
of the boiler tubes R; and this chamber I fix in the smoke box against or near
the boiler plate so that the hot gases and flame shall pass through the said tubes S
on their way to the chimney, and shall superheat the steam-The chamber is fitted
with a suitable blast nozzle N, discharging into the funnel or chimney-Into this
chamber for the purpose of superheating and rendering same invisible, I lead the
exhaust steam from the engines and waste steam from the safety valves through
suitable pipes, interposing suitable expansion chambers and drain pipes to intercept
and lead off any condensed steam-Alternatively, I may construct my superheating
chamber as shewn in Figure 4 in the form of a helical coil, the piping or pipes H
placed and connected as aforesaid.
My said superheating device I employ conjointly with the other several parts
constituting a traction engine, but which, as my improvements do not particularly
relate to them, I do not now specify.
And having now fully described and ascertained the nature and object of my
invention and the manner of its performance, be it known that what I consider
Hovel and claim under my letters patent is:-
1st. The combination in a traction Engine of wormed driving shaft provided
with compensating collars and spur wheeled bearing wheel shaft substantially as
specified
2nd In a traction Engine boiler the construction of tubes in a reverse curve
substantially as and for the purpose set forth.
+
3rd In a traction Engine the construction of a boiler with short horizontal
barrel in combination with the hanging tubes from the fire-box crown and the
reverse curved boiler tubes substantially as and for the purposes set forth.
4th In a traction Engine boiler the combination with the boiler tubes and
construction of a superheater consisting of coincident tubes in a chamber
substantially as and for the purposes set forth.
5th In a traction Engine boiler the combination with the boiler tubes and
construction of a superheater consisting of a helical coil in a chamber substantially
as and for the purposes set forth.
6th In a traction engine the combination with the known parts of the various
devices herein before specified and claimed.
⚫ In witness whereof I, the said William Wilkinson, have hereunto set my hand
and seal this Eighth day of May in the year of our Lord One thousand eight
hundred and eighty-four.
WM WILKINSON Gol