In- PROVEMENTS IN APPARATUS FOR COMMUNICATING BETWEEN THE PASSENGERS, GUARDS, AND ENGINE DRIVERS OF A RAILWAY TRAIN
Year: 1867

page_text: LETTERS PATENT to Josiah Latimer Clark, of 5, Westminster Chambers,
Victoria Street, in the County of Middlesex, for the Invention of "In-
PROVEMENTS IN APPARATUS FOR COMMUNICATING BETWEEN THE PASSENGERS,
GUARDS, AND ENGINE DRIVERS OF A RAILWAY TRAIN:"
Sealed the 12th November 1867, and dated the 17th May 1867.
PROVISIONAL SPECIFICATION left by the said Josiah Latimer Clark at
the Office of the Commissioners of Patents, with his Petition, on the
17th May 1867.
I, JOSIAH LATIMER CLARK, of 5. Westminster Chambers, Victoria Street,
in the County of Middlesex, 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:-
My Invention or improvement consists in the application of a pneumatic
tube running the whole length of the train, with suitable means for making
connection between the carriages and break vans when coupled together so
as to form a train. Upon each break van and upon the engine is provided an
air pump or bellows worked by the movement of the wheels, which is con-
nected with the pipe above mentioned, and exhausts the air from it (or it may
be forces air into it) whenever the train is set in motion: the air which is
ejected from the pipe by the action of the pump or bellows is forced through
a spring piston in such manner that at every stroke of the pump the piston is
[Price 8d.1

page_text: ceasc.
thrust forward by the air and causes a hammer to strike a bell and attract
the attention of the driver or guards on whose vehicle the apparatus is fixed;
as soon however as a certain degree of vacuum has been produced the pump
will cease to eject any more air from the pipe and the action of the bell will
Provision may be made for throwing the pump out of gear as soon as
a sufficient vacuum is attained. so as to prevent unnecessary wear. The pipe
has in every compartment, and also in the guard's van, and on the engine, a
suitable tap, valve, or plug which can be opened (with a provision that when
once opened it cannot be again closed or restored to its former appearance
and condition). and this plug when removed admits the air to the pipe, and
thereby again sets the pistons and bells into action, so that on one of these
plugs being opened in any part of the train, either by design or by the sepa-
ration of the carriages, the whole of the bells in the train are set in motion by
their respective pumps, and thus the guard can call the attention of the driver
or the passengers can attract the attention of both driver and guards at any time.
In place of the bell a whistle or any other sounding apparatus can be used, or
the air may set in motion any other machinery for attracting the attention of
the officials. The pressure of air may also be employed in place of vacuum,
the apparatus will then work in the reverse manner: flexible tubes are used
in connecting the carriages of the train together, with a spigot and faucet
arrangement for connecting their ends together, so that they may readily pull
asunder without injury when the carriages are disconnected, or an oblique flat
hayonet joint with two similar ends may be employed.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Josiah Latimer Clark in the Great Seal Patent Office on the
16th November 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSIAH
LATIMER CLARK, of 5, Westminster Chambers. Victoria Street, in the County
of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventeenth day of May, in the year of our Lord
One thousand eight hundred and sixty-seven, in the thirtieth 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

page_text: 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, use, 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 performed, 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 my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
My Invention consists in the application of a pneumatic tube running the
whole length of the train, with suitable means for making connection between
the carriages and break vans when coupled together so as to form a train.
A pump or bellows is fixed on the engine, and upon or beneath every guard's
van, which is kept in constant action by the motion of the train, and conti-
nually exhausts the air from this pipe, all the bellows acting on the pipes simul-
taneously; under ordinary circumstances the pipe being closed no air can be
ejected by the bellows, and no effect will be produced in the guard's van or
engine, but if an opening be intentionally made into any part of the pipe by
the passengers or guards, or by the accidental separation of the train into
two parts, the air will be freely admitted into the pipe, and all the bellows will
come into action, and will begin to eject air violently. This air is ejected
through a powerful whistle or other sounding apparatus, and by the noise it
occasions it immediately attracts the attention of all the guards in the train,
and also that of the engine driver. Flexible tubes of vulcanized india-rubber
with spiggot and faucet joints are employed for making the connections
between the carriages.
In the accompanying Drawing, Figure 1, a is an excentric or crank fixed
on the axis of a wheel b, which is driven by a strap passing round the axis of
one of the wheels of the guard's van, and therefore revolves whenever the
train is in motion; c is a rod working in guides, to which is attached the

page_text: bellows d. A pipe leading from the bellows passes up into any convenient
part of the guard's van, where it is in free communication with an air chamber
e, e; this air chamber is connected with the pneumatic pipe f, which runs the
whole length of the train, and which communicates with the similar chambers
and bellows on the cagine and on the other vans. The pipe f where it enters
,this chamber is provided with a valve g, which freely permits the air to enter,
but prevents its exit. The whistle h is also provided with a valve i, which allows
the air to pass out from the chamber e through the whistle, but prevents its
.entry. As soon as the train is set in motion all the bellows commence to
work, and at each stroke they exhaust a portion of air from the respective
chambers e, e, and the pneumatic pipe f, and eject it out again through the
valves i and whistles h, causing them all to sound loudly. After a very few
strokes, however, they have between them exhausted as much air from the main
pipe as their construction permits, and have created a partial vacuum, and
since no more air can enter at any part of the apparatus the whistles neces-
sarily cease to act and become silent, and they continue so however long the
train may be in motion. If now the passengers wish to make a signal to the
guard and engine driver, or if either of the guards wishes to make a signal to
the engine driver it is only necessary for either of them to make an opening
into the pipe (by means of a suitable valve provided for the purpose), and
immediately the air enters freely into all the bellows, and the whistles both in
the guard's van and on the engine commence and continue to sound loudly
as long as the air is admitted to them. In the case of the passengers it is
proposed that the valve shall be of such a construction that when once opened
it cannot be closed again, and the signal is therefore a continuous one until
the guard arrives, who has means of closing it, but in the guard's van and on
the engine a simpler valve is provided which can be opened and closed at
pleasure, by which means they can signal to each other as often as they find
necessary; in the event of one part of the train becoming accidentally detached
it is obvious that all the whistles will instantly commence sounding. The
object of the air chamber e is two-fold; one is, that of bringing the valves and
whistles into a part of the van where they can be readily heard and attended
to (in the event of their requiring attention), the whole apparatus is in fact
readily removed bodily and exchanged for a new one as often as requisite, all
the connections being formed by short lengths of vulcanized india-rubber tubing;
the other object is that of preventing too high a vacuum in the main tube,
which would be objectionable as tending to create a greater leakage, which
leakage if very considerable would be ejected through the whistles in sufficient

page_text: quantity to cause them to give a constant sound, which might in an extreme
case occasion some difficulty in distinguishing it from the intentional signals.
I prefer therefore to work with a vacuum of not more than 5 or 6 ounces
on the square inch, the requisite degree of vacuum being obtained once for all
by duly apportioning' the relative sizes of the bellows and of the air chamber e.
In Figure a bellows has been shown as the means of producing the
vacuum, it is obvious, however, that a pump or any other suitable machine may
be employed for this purpose.
In Figure 2 a pump is shown in connection with the same apparatus.
The same letters correspond to the same parts in each Figure respectively,
and it is unnecessary to give any further description of the Figure. It is also
obvious that any other form of air-sounding apparatus may be used instead of
a whistle.
Figure 3 shows such an arrangement, in which a small cylinder has
a piston working loosely in it, and carrying a hammer, which at every stroke
of the pump or bellows strikes a gong or bell. The hammer is pressed
home against its stop by a light spring k, and when in this position the
piston closes the cylinder, and at every impulse of air from the bellows it is
driven forward, and the hammer strikes the bell, at the same time it discloses
a slot or number of slots I (only two of which are shown in the Drawing);
these slots or openings in the side of the cylinder allow the air to escape, and
the piston is pressed back again by the spring k to its normal position ready
for another stroke. As soon as the exhaustion of the main pipe is complete
no more air can be forced into the cylinder, and therefore the bell remains
silent.
Figure 4 shows a carriage with a part of the main pipe fixed beneath it,
or it may if preferred be led along the top of the carriage; this pipe is of
wrought-iron gas pipe, about inch in diameter; at each end of the carriage
it is bent downwards, as shown at m, m, and a short length of flexible india
rubber pipe n is attached to it by a union joint, and when out of use is allowed
to hang loosely, or to lie over a hook conveniently placed to sustain it. When
the carriages are coupled up these pipes are connected by a joint o, which is
shown separately in Figure 5, and will be described hereafter. p. p, Figure 4,
show the means of communication for the passengers, a branch p is led up
from the main pipe f between the divisions of the carriages (or in any other
convenient position), at the top is shown a T-piece which opens into either
compartment of the carriage. These openings are securely closed by metal
plugs provided with handles, which by the application of force may be drawn

page_text: out so as to admit air and give signals to the guard's vans and the engine; the
plugs when fixed have ornamentally printed discs of leather or paper glued
over them, with instructions as to their use, which leather is permanently
torn away when the plug is removed, so as to indicate the compartment in
which any signal was given, the plugs are also provided with expanding spring
edges, as shown in Figure 6, so that when once removed they cannot be
re-inserted in the same hole, or the plug may be inclosed within a box, so as
to be inaccessible, and connected with the handle by a cord, as shown in
Figure 7. A glass or parchment covering may be substituted for these plugs,
which would have to be broken and destroyed as often as it became necessary
for a passenger to give a signal.
Figure 5 shows the method of coupling the carriages together. n, n, are
flexible india-rubber tubes attached to the main pipe f; o is a hollow spigot
of wood or metal, hanging to the carriage by a chain or cord, and having both
its ends tapered so as to fit the india-rubber tubes, which are enlarged and
strengthened at their ends for this purpose. When the carriages are coupled
together it is only necessary to take the spigot in hand and thrust its two
ends into the corresponding flexible tubes; they do not require uncoupling,
but are allowed to draw out of themselves when the carriages are separated.
It is obvious that all these effects may be obtained with a slight modification
of the apparatus by the use of compressed air instead of vacuum, the pump or
bellows in this case being employed to draw air through a whistle or other
sounding apparatus, and to force it into the tube, arrangements being made
for stopping the action of the pump when the pressure in the pipe arrives at
any point determined on. When the air in the pipe is at such a pressure that
the pump ceases to act the whistle or sounding apparatus ceases to sound, but
when air is allowed to escape at any point from the pipe by the, removal of one
of the plugs the pressure in the pipe is decreased, and the pump immediately
commences to draw air through the sounding apparatus, and causes it to
sound continuously. Provision may also be made for throwing the pump or
bellows out of gear as soon as a sufficient vacuum is produced so as to avoid
unnecessary wear; this is effected by a cylinder and piston of somewhat large
diameter, connected with the main pipe in such manner that when the requi-
site degree of vacuum is obtained the piston is drawn into the cylinder, and by
this movement throws the pump out of gearing with the driving pulley; the
piston being forced back by a spring into its normal position as often as the
vacuum falls short of the requisite amount. The same result may be obtained
by making a friction connection between the driving pulley and the axis of

page_text: the pump crank, which will allow the latter to slip whenever the vacuum is
sufficiently complete, so that the pump will cease working until such time as
more air is admitted to the main pipe.
In witness whereof, I, the said Josiah Latimer Clarke have hereunto set
my hand and seal, this Fifteenth day of November, in the year of our
Lord One thousand eight hundred and sixty-seven.
JOSIAH LATIMER CLARK. (L.S.)