IMPROVEMENTS IN STEAM TRAMWAY ENGINES
Year: 1884

page_text: COMPLETE SPECIFICATION.
We WILLIAM PENROSE GREEN and JOHN WALKER both of the Smithfield Iron
Works Leeds in the County of York Engineers do hereby declare the nature
of our Invention for "IMPROVEMENTS IN STEAM TRAMWAY ENGINES" and in
what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :---
This Invention has for its object improvements in steam tramway engines and
it applies especially to steam tramway engines in which the cylinders are arranged
vertically over the crank shaft and in which the crank shaft lies in the same
horizontal plane with the axis of the driving wheels which receive motion from it
by means of the spur gear. In such engines we give motion to the governor by
means of a bevelled wheel upon the end of the crank shaft within the main frame
and this gears with a pinion upon the lower end of the governor spindle. The
governor spindle is situate on the outer side of the main frame and a hole is cut in
this frame to admit the bevelled gear. The governor is intended to shut off the
steam and apply the brakes instantly when the maximum permissible speed of
running is exceeded.
The governor gives movement to a rod which at its upper end carries a wedge
piece aud by the divergence of the governor balls this wedge piece is drawn
downwards. The way in which at a certain pre-arranged speed this wedge piece
causes the steam to be shut off from the engine and the brakes to be applied is
hereinafter described.
From the upper end of the governor spindle a speed indicator may be driven.
The same valve is used to throttle or shut off the steam and for, admitting steam
to the brake cylinder. This valve is a piston or slide capable of movement to and
fro in a cylindrical valve chest. Steam is admitted from the boiler to this valve
chest by a passage at one end.
The piston valve has a rod attached to it and a collar upon the valve rod is
embraced by the forked end of a lever which is inoved by the driver of the engine
for the purpose of checking the progress of the engine either by throttling tho
steam or when this is insufficient by applying the brakes. The piston valve is
thus moved along within the cylindrical valve case and thereby caused to cover or
partly to overlap and close the ports in the valve case by which the steam passes
forward to the working cylinders. There is in addition an ordinary stop valve
which is used for permanently shutting off the steam when a stoppage of some
duration is to be made.
At the same time that the piston valve closes the steam ports it uncovers another
port in the side of the cylindrical valve case which allows steam to pass into the
brake cylinder, the steam acting in this cylinder causes the brakes to be applied in
the usual way.
The movement of the piston valve in the contrary direction at the same time
that it uncovers the steam ports leading to the cylinders and covers thoso leading
11

page_text: to the brake cylinder brings a cavity in the side of the piston valve to such
a position as to place in correspondence two passages one leading from the brake
cylinder and the second a passage by which the steam finds a free outlet.
But this valve in addition to being worked manually by the engine driver
is placed under the control of the governor and this is done in the following
manner-
The end of the valve spindle is provided with a head which when the valve.is
so placed as to open wide the passage for the steam to the working cylinders abuts
against the head of a forked lever. The lever at its other end has a spring applied
to it but the spring is at this time prevented from moving the lever by a sliding
bolt. The end of the bolt enters and engages with the hole formed in the lever for
the purpose.
There is also another bolt, and this secures upon the valve spindle the collar
upon which the hand lever operates and by which the driver of the engine works
the valve. These bolts are connected together by a cross piece and a spring presses
them both forward and causes them to engage. The arrangement is such as to
admit of the last mentioned bolt partaking in the to and fro movement of the valvo
spindle when the valve is workel by hand. The governor operates to withdraw
simultaneously both these bolts when the speed at which the engine is travelling
becomes unduly high and this it does by means of the wedge already mentioned.
The wedge is then drawn downwards and acts against the cross piece connecting
the bolts and draws them out. The spring attached to the lever is then free to act
and it moves the valve shuts off the steam from the driving cylinders and applies
the brakes this it does not only automatically but in such a manner that the driver
cannot interfere with the action his hand lever being at this time disconnected.
In order that our said Invention may be most fully understood and readily
carried into effect we will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a side elevation of a steam tramway engine with governing. driving
gear arranged in accordance with our Invention.
Figure 2 is an end elevation partly in section and
Figure 3 is a plan of the same.
Figure 4 shows separately to a larger scale the automatic and hand throttle and
brake valve with the parts connected therewith.
-
Figure 6 is an end elevation of Figure 4.
Figure 6 is a plan partly in section of the parts shown in Figure 4.
A A are the main cylinders of the engine.
B is a crank shaft to which pistons and connecting rods give motion. There are
spur wheels not shown in the figure gearing the crank shaft with the axle of the
driving wheels as is usual in this class of engine.
Upon one end of the crank shaft B we secure a bevelled wheel C and we cut
a hole at C in the side frame of the engine to receive this wheel.
The wheel gears with a pinion D upon the governor spindle E which is
placed just outside the main frame.
F is the governor it is arranged in the usual manner and by means of a rocking
lever it operates a rod G. The governor spindle is prolonged at H for the purpose
of driving a speed indicator.
The rod G at its upper end carries a wedge picce G¹ which is also seen in
Figures 5 and 6.
I is a valve which is employed to throttle and cut off the steam in its passage to
the engine and for applying the brakes.
K is the cylindrical ense in which this valve works.
L is a passage admitting steam to the valve case, and this steam with the valve
in the position in which it is represented in these Figures, passes by the valve and
by the ports M M into the passage N leading to the driving cylinders to which this

page_text: steam is supplied by slide valves in the usual manner.
O is the ordinary stop
valve which is closed when a stoppage is of any duration and when running is
opened more or less as may be found necessary.
In the position in which the valve I is here shown the cavity I' in its side covers
the two ports P and Q the latter of which is in communication with the brake
cylinder and the former is a free outlet.
In this position of the valve the brakes are off, and no pressure is exerted upon
the piston in the brake cylinder; the movement of the valve to the left however
will allow steam to pass by the port R into the brake cylinder, and at the same
time it will close the communication between this cylinder and the outlot passage P.
At the same time as the Drawing indicates the piston valve will close the steain
ports M. M. by which the steam goes forward to the engine.
S is the lever by which the driver controls the valve, it is connected in the
manner shown in Figure 1, with two handles one or other of which is always
readily accessible to the engine driver.
When the lever S is this moved its forked end operates upon the collar T on the
valve stem and the bolt U at this time secures the collar in its place. The bolt U
moves with the valve spindle and traverses in a slot in the cross piece V. The
valve stem also in the movement thus given to it by the hand levors slides to and
fro between the jaws of the forked lever W.
This lever as represented in the Drawing is held in place by the sliding bolt ✗
otherwise the upper end of the lever would be drawn outwards or to the left by
the coiled spring Y in the cylindrical valve box Z. This spring is held compressed
between the end of the box and the disc a' upon a stein a. which is jointed to the
lower end of the lover W.
As the speed of the engine rises the weige piece G¹ is drawn downwards in the
manner already described and as the wedge piece descends it forces the bolts V
and X with it.
At a certain speed these bolts liberate the parts which they retain and thereupon
the spring Y operates at once to move the valve to the left, thereby shutting off
the steain from the engines, and applying the brake in the manner already
described.
Having now particularly described and ascertained the nature of our said
Invention and in what manner the same is to be performed, we declare that what
we claim is—
First. The arrangement of the governor its spindle being mounted out-ide the
main frame and having a bevilled pinion upon it gearing with a corresponding
wheel on the crank shaft, a hole being cut in the side frame to receive this gear as
herein described.
Second. The arrangement of the throttle and brake valve in connection with
spring (or its equivalent) which when liberated operates to shut off the steam
and apply the brake and effecting the liberation of the said spring by the governor,
substantially as described.
Third. Hand and automatic stop gear which remains under the control of the
Iriver until the speed becomes excessive and then automatically operates
ndependently of the driver, the said gear being arranged, substantially as
herein described.
CARPMAEL & Co.,
Agents for the Applicants.