IMPROVEMENTS IN APPARATUS FOR COMMUNICATING BETWEEN THE PASSENGERS, GUARDS, AND ENGINE DRIVERS OF A RAILWAY TRAIN
Year: 1868

page_text: LETTERS PATENT to Josiah Latimer Clark, of Beechmont, Sydenham
Hill, in the County of Surrey, for the Invention of "IMPROVEMENTS IN
APPARATUS FOR COMMUNICATING BETWEEN THE PASSENGERS, GUARDS, AND
ENGINE DRIVERS OF A RAILWAY TRAIN."
Sealed the 16th February 1869, and dated the 21st August 1868.
PROVISIONAL SPECIFICATION left by the said Josiah Latimer Clark
at the Office of the Commissioners of Patents, with his Petition, on
the 21st August 1868.
I, JOSIAH LATIMER CLARK, of Beechmont, Sydenham Hill, in the
5 County of Surrey, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN APPARATUS FOR COMMUNICATING BETWEEN THE PASSENGERS,
GUARDS, AND ENGINE DRIVERS OF A RAILWAY TRAIN," to be as follows:-
This Invention has for its object improvements in apparatus for
communicating between the passengers, guards, and engine drivers of a
railway train.
These improvements consist in the application of a tube extending
from end to end of the train containing air, which is either exhausted or

page_text: compressed by means of a pump, bellows, or similar machine worked
from the axles of the tender or carriage, or from some moving part of
the locomotive engine. A bell or other sounding apparatus is fixed upon
the engine or tender and in cach of the guards' vans, and is so arranged
as to sound instantly as long as the train is in motion, the power for
working the said apparatus being taken from the wheels or springs or
other moving parts of the train. The apparatus is however further
arranged in such manner that whenever the vacuum or pressure is
maintained by the pump or bellows the bell or sounding apparatus is
silenced either by its being thrown out of gear or by the hammer being
removed out of its reach. By this arrangement, so long as the train is in
motion and the vacuum or pressure is maintained, the sounding apparatus
remains silent in consequence of its being out of the influence of the
hammer or other sound producer; but if the guard or passengers in any
part of the train destroy the vacuum or pressure by opening a suitable
valve provided for that purpose the bell or other sounding apparatus
comes under the influence of the moving hammer or other sound pro-
ducer, and a signal is thereby given to the guard and to the driver of the
engine simultaneously, and continues to be given as long as the train is
in motion.
One of the methods which I employ to put the sounding apparatus out
of gear during the time the pump or bellows is in action is by suspending
or balancing it upon a lever held and guided by the elastic covering
of a drum. The interior of this drum is in direct communication with
the tube, so that when the air is exhausted the elastic covering is
depressed by the force of the atmosphere without, and the bell or other
sounding apparatus removed from the influence of those portions moved
by the train itself.
-
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Josiah Latimer Clark in the Great Seal Patent 3
Office on the 19th February 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSIAH
LATIMER CLARK, of Beechmont, Sydenham Hill, in the County of
Surrey, send greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-first day of August, in the year
of our Lord One thousand eight hundred and sixty-eight, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Josiah Latimer Clark, Her special licence
that I, the said Josiah Latimer Clark, my executors, administrators,
and assigns, or such others as I, the said Josiah Latimer Clark, my
executors, administrators, and assigns, should at any time agree with, and
no others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, usc, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
APPARATUS FOR COMMUNICATING BETWEEN THE PASSENGERS, GUARDS, AND ENGINE
DRIVERS OF A RAILWAY TRAIN," upon the condition (amongst others)
that I, the said Josiah Latimer Clark, my executors or administrators,
by an instrument in writing under my, or their, or one of their
hands and seals, should particularly describe and ascertain the nature
of the said Invention, and in what manner the same was to be per-
formed, and cause the same to be filed in the Great Seal Patent Office
within six calendar months next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that I, the said Josiah Latimer Clark, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed; to be particularly described and ascertained in and
by the following statement thereof, that is to say :-
These improvements consist in the application of a tube extending
from end to end of the train containing air, which is either exhausted or
compressed by means of a pump, beliows, or similar machine worked
from the axles of the tender or carriages or from some moving part of
the locomotive engine. A bell or other sounding apparatus is fixed upon
the engine or tender and in each of the guards' vans, and is so arranged
as to sound incessantly as long as the train is in motion, the power for
working the said apparatus being taken from the wheels or springs or
other moving parts of the train. The apparatus is, however, further
arranged in such manner that whenever the vacuum or pressure is
maintained by the pump or bellows the bell or sounding apparatus is
silenced, either by its being thrown out of gear or by the hammer being
removed and held out of its reach. By this arrangement, so long as

page_text: the train is in motion and the vacuum or pressure is maintained, the
sounding apparatus remains silent in consequence of its being out of
the influence of the hammer or other sound producer. But if the guards
or passengers in any part of the train destroy the vacuum or pressure
by opening a suitable valve provided for that purpose the bell or other
sounding apparatus comes under the influence of the moving hammer
or other sound producer, and a signal is thereby given to the guards and
the driver of the engine simultaneously, and continues to be given as
long as the train is in motion.
Having thus described the nature of my Invention, I will proceed to
describe more fully the manner in which I prefer to perform the same.
In carrying out my Invention I prefer to employ a small air pump
attached to the engine or to some other part of the train, which as long
as the latter is travelling produces a partial vacuum (equal to about half
a pound to the square inch) in the whole length of the tube. Under-
neath each of the guards' vans and the tender a cylinder is fixed, in
which a piston or a bellows is acted upon by the partial vacuum, and
throws the bells or whistles out of gear as long as the partial vacuum is
maintained. It follows from this that when the train first moves the
bells begin to sound, but immediately afterwards a partial vacuum is
produced and all the bells are thrown out of gear, and therefore remain
silent as long as the train continues in motion. If, however, any person
in any part of the train opens a communication between the tube and
the atmosphere the vacuum is destroyed, and all the bells are brought
at once into play and continue to ring until the communication is closed
again or until the train stops. When the guard wishes to signal to the
driver or the driver to the guard he does so by simply opening a cock
communicating with the atmosphere and closing it again at pleasure,
thus giving signals of any length. When however a passenger wishes
to signal he pulls a handle which removes a plug from out of the side
of the tube, and thus opens it to the air which rushes in and causes
the bells to ring, and they continue to do so until the train stops, as he
lias no means of replacing the plug.
The separate parts of the apparatus are as follows:-
1. The Air Pump. The pump on the engine or tender is a small iron
barrel with a brass plunger making a six-inch stroke, and fitted with
ordinary leather valves.

page_text: 2. The tubes consist of about half or three-quarter inch iron gas pipe
fixed permanently over the tops of the carriages and down the ends.
The connections between the carriages are made by a short length of
india-rubber garden hose, as described in my former Patent, dated the
17th day of May 1867 (No. 1471). Over each passengers' compartment
the tube is supplied with a T-piece, into the lower branch of which a
plug is fitted, being connected by means of a chain with a knob or
handle inside the compartment. The passenger pulling down the knob
removes this plug, and is prevented raising the handle again by a wedge
falling within its shaft.
3. The alarums or signal bells are of a size and strength suitable to
the rough wear and tear and noise of a railway train. They are pro-
tected from the dust and dirt by a strong perforated casing. They are
struck by hammers which receive direct motion from the train, and
there is therefore no limit to the force which may be employed to set
them in motion. When a whistle is employed instead of a bell it is
worked by means of a bellows, which is driven by similar means to
those used for giving motion to the alarum bells. The whistle is con-
nected with the bellows by a pipe, and is placed by preference upon the
engine at the back of the weather board near to the ear of the driver of
the train.
.
4. The Driving Gear.-The pump or bellows for forming the vacuum
is by preference driven directly from one of the axles of the tender,
either by a band passing round it and round a pulley on the shaft of
the pump, crank, or by a friction wheel on the crank shaft, the periphery
of which is pressed by a spring against one of the axles, and is thereby
caused to revolve. It is therefore in constant motion whilst the train
is travelling, and creates a partial vacuum in the series of tubes along
the train. This vacuum needs never exceed a certain pressure, and
may, it desired, be regulated by a safety valve opening inwards. The
motion which actuates the hammers of the bells may be in like manner
obtained by means of a crank on the axle of a friction wheel, which
presses upon one of the axles underneath the guard's van, or underneath
the tender. The crank end of the axle is then supported by a fixed
bracket from the bottom of the vehicle, but the end which carries the
friction wheel is suspended by a hanger turntable about a centre. A
shallow cylinder or bellows is fixed underneath the carriage, and is
conuected with the vacuum tubes,
which when a partial vacuum

page_text: is formed in it, it is drawn back, pulling the friction wheel away from
the axle, thus stopping its motion and the ringing of the bell. It is
consequently silent as long as there is a vacuum formed in the tubes, but
as soon as this is destroyed the bell or whistle continues to sound.
DESCRIPTION OF THE DRAWINGS.
The Alarm Bell.-Figure 1 shows a part view of one of the forms
of alarm bell used upon the side of the tender and inside or on the
roof of the guard's van.
The bell A, A, is fixed by a pillar in its centre firmly to the back
plate B, B, B, and is struck when signalling by the hammer C. The
hammer head is carried upon the end of a shaft or lever C¹, C¹,
turning upon the centre pin D fixed to the back plate, and is provided
with a projecting nose E and a vertical continuation which is held by
the pin and jaw J attached to the spring I, I, by whose tension the
hammer is therefore forced towards the bell. Motion is given to the
hammer by means of the slide M, M, working on two pins N, N',
through corresponding slots. This slide is moved up and down by a
crank on the end of a shaft turned by means of either a friction wheel
or a pulley, in either case receiving direct motion from the train.
Attached to the slide M, M, is a firm pin O, which when the slide
is descending meets the end G¹ of the beam or working lever G¹, G, G¹,
whose fulcrum is at H, and elevates thereby its further end F. This
end F. is provided with a snapper which is rigid in ascending but loose
in descending. Thus when the end F is elevated this snapper pushes
up the nose E before it and holds it against the force of the spring I, I,
to the point where the circles described by F, H, and E, D, intersect
each other. Then the nose E being liberated the spring accelerates the
hammer (which was drawn back with the nose E) towards the bell
and strikes it. When the slide M, M, is raised up again the rocking
lever G, G, falls back by its own weight into its proper position, and the
snapper F passes without resistance over the nose E. During the time
the train is in motion therefore the slide M, M, is continually moving up
and down. In order however to prevent the bell being struck when
no signal is intended to be given, the end of the rocking lever G, G,
is attached by means of an articulated chain L, L, with an clastic
diaphragm drawn over the mouth of a chamber K, K, which is in
connection with the vacuum tubes. When the vacuum is established

page_text: therefore in the tubes, that is to say, when the pump is at work and no
part of the tube is open to the atmosphere, the elastic diaphragm in'
question is drawn upwards and with it the chain L, L, and left-hand
end of the rocking lever. During this time the end G¹ of the same
is consequently depressed correspondingly, so that the pin O of the
slide M, M, travels up and down without touching it. On a signal
being given from any part of the train, by destroying the vacuum as
before stated the air entering the chamber K, K, allows the diaphragm to
descend and with it the snapper end F of the rocking lever. The latter
comes within the play of the pin O and is rocked at each rise and
fall of the slide, thereby ringing the bell during the time the vacuum;
remains broken.
Figure 2 shows a different arrangement of alarm bell, the same being
worked by the force of the air set in motion by a pump underneath
the tender or guard's van. This form of alarm is preferred in positions
where it is difficult to convey motion from the train, as for instance.
at the back of the weatherboard of the engine, the communication
being in this case effected by a double or single pipe. Underneath
the tender or guard's van is the pump formed of a cylinder C¹, at
whose ends are enlargements A, A, and A', A', and in which is a
piston P¹ whose rod receives direct motion from the train by means of
a friction wheel pressing upon one of the axles. The stroke of this
piston is made to be of the whole practicable length of the cylinder,
so that the air after being compressed into one end immediately
recovers its equilibrium on the piston entering one of the enlargements
at the ends of the cylinder. From the the ends of this pump cylinder
are air tubes T and T" passing up through the bottom of the tender or
van to the point where the alarm bell is placed. These pipes are con-
nected here with the two ends of the cylinder C, in which is a piston P
whose rod passing through the covers carries at its ends the hammer
heads H and H' which strike against the edge of the bell B, B, with
which the cylinder C is covered. When a signal is given and the
friction wheel underneath allowed to fall upon the rotating axle of
the train the pump is set in motion, compresses the air into one side
of the cylinder C and draws it out by the other side, by which the
piston P is forcibly impelled to one end of the cylinder and the bell
struck by the hammer. Arrived at the end of its stroke the pump
piston enters the enlargement, and the air in the whole system is for

page_text: a moment equeated, then the piston returning forces the air in the
other direction, thereby striking the bell on the other side.
The Whistle. Figure 3 shows the arrangement of the apparatus when
a whistle is employed instead of an alarm bell. The bellows B, B,
(set in motion by the rotation of the train axle against the friction
wheel, on the shaft of which is a crank connected with them) are
connected by means of a pipe E, E, with the whistle A placed upon
the engine or in the van where it is required to sound. So long as
the bellows are at work therefore the whistle continues to sound.
When no signal is given the friction wheel is drawn off by the vacuum
and continues off until the tube in some part of the train is opened;
then it falls on the axle and causes the whistle to sound. The friction
wheel driving gear is shown in Figure 4. The bellows A, A, are fixed
underneath the tender or van and are in connection with the vacuum
tube system B, B, which passes along the train. The front side of the
bellows is drawn back when a vacuum is formed and pulls the
hanger D, D, backwards and with it the friction wheel E, E, away
from the axle F. This hanger D, D, is held by the tension of the
spring G, so that when no vacuum is formed in the bellows the
wheel E, E, is pressed by the force of this spring against the axle.
The arbor of this friction wheel is held at one end by the moveable
hanger before mentioned and at the other (that carrying the crank)
by a fixed bracket.
In witness whereof, I, the said Josiah Latimer Clark, have here-
unto set my hand and seal, this Eighteenth day of February,
in the year of our Lord One thousand eight hundred and sixty-
nine.