IMPROVE- MENTS IN MEANS OR APPARATUS FOR EFFECTING INTERCOMMUNICATION IN TRAINS, PARTLY APPLICABLE TO OTHER PURPOSES
Year: 1873

page_text: LETTERS PATENT to Edwin Thomas Truman, of Old Burlington
Street, in the County of Middlesex, for the Invention of "IMPROVE-
MENTS IN MEANS OR APPARATUS FOR EFFECTING INTERCOMMUNICATION IN
TRAINS, PARTLY APPLICABLE TO OTHER PURPOSES."
Sealed the 24th April 1874, and dated the 27th October 1873.
PROVISIONAL SPECIFICATION left by the said Edwin Thomas Truman
at the Office of the Commissioners of Patents, with his Petition,
on the 27th October 1873.
I, EDWIN THOMAS TRUMAN, of Old Burlington Street, in the County
of Middlesex, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN MEANS OR APPARATUS FOR EFFECTING INTERCOMMUNICATION IN
TRAINS, PARTLY APPLICABLE TO OTHER PURPOSES," to be as follows:-
My Invention primarily relates to the use of tubes extending along
the train from carriage to carriage for enabling the passengers, guards,
and driver to communicate with and even to talk to each other in
case of need. For a system of this description to be perfect the tubes
of adjoining carriages must be easy to couple together in making up

page_text: a train; the tubes and their connections between the carriages must be
perfectly air-tight; the branch tube in each compartment of the several
carriages must be closed in such a way that while the end may be readily
uncovered by a passenger yet he cannot reinstate or replace the cover to
avoid identification; there should be distinct means of communication
between the. guard and driver or between the front and rear guards; and
the whole arrangement must be simple and inexpensive.
My Invention consists in the combined means or apparatus herein-
after described for fulfilling the requirements above indicated, also in
an improved mode of forming the tube connections in an improved
mouth piece for the ends of the branch tubes, and in means whereby the
passengers can shut off the communication through the tubes between
their own carriage, and either end of the train so as to compel all the
sound to travel to the other end of the train.
I carry along the top or at other, convenient part of every carriage
two distinct tubes of gutta percha, india-rubber, metal, or other suitable
material. The ends of these tubes extend beyond the ends of the carriage
and terminate in flexible connecting pieces at one or both ends, to
enable them to be coupled to corresponding connecting pieces on the
adjoining carriages. These connecting pieces must be so arranged that
no matter which ends of two carriages come opposite each other the
male connecting piece of one carriage shall meet the female piece of the
other, and vice versa. For this purpose I provide each tube with a
male piece at one end and a female piece at the other, in such manner
that the two male picces of the two tubes of the same carriage are
diagonally opposite each other, care being taken that all the carriages
have the male picces in the same position, for instance, let the male
piece be always at the right and the female piece at the left when a
person faces either end of the carriage. In this way it will be impossible
for two male pieces or two female pieces to meet each other.
The manner in which I prefer to form the tube connections is by
means of a collar or outer tube into which the ends of the two tubes to
be connected are inserted, the collar being then moved so as to bring the
ends of the two tubes close together and make a joint.
The tubes of the last carriage of the train should be connected to
tubes in the guard's van, and those of the first carriage to tubes leading
to a position near the engine driver or to tubes in the front van, when

page_text: there is one, or the tubes may terminate in any other suitable part of
the train.
From one or both of the tubes of every carriage I carry branch tubes
into the several compartments of the carriage, and I close the end of
each branch tube with a diaphragm of india-rubber or other suitable
material, or, with any other air-tight device which may readily be torn
off or burst, but cannot again be replaced or reinstated by a passenger;
and I prefer to arrange the closing device in such manner that the very
act of tearing it off or bursting it shall move the air in the corresponding
tube, and thereby act upon a whistle in the guard's van or wherever the
main tube may finally terminate. In any case as soon as the closing
device is torn off or burst, and the whistle (when such is used) in the
guard's van removed, the passengers in the compartment can talk with
the guard, and in fact every sound in the compartment will be conveyed
through the tube and can be heard by the guard.
The guard and driver or the front and rear guards can at all ordinary
times freely communicate with each other through either of the main
tubes, and when their communication through one tube is interfered
with by a passenger opening a branch tube, their means of com-
munication through the other main tube still remains intact.
The means by which the branch tubes may be so closed that the very
act of opening them moves the air in the main tube as before-mentioned
may consist simply of an elastic diaphragm secured over the mouth
piece of the branch tube, and provided with a ring or handle for pulling
it off the mouth piece; when the ring is pulled the diaphragm will
stretch before leaving the mouth piece, and thereby produce a sufficient
movement of the air in the tube to sound the whistle, which whistle I
prefer to make double acting so that it will sound both when the air is
moved into the tube and out of the tube at that end; or the ring may be
dispensed with, in which case the diaphragm must be burst by being
pushed inwards, and this action will move the air in the tube sufficiently
to sound the whistle; or an elastic ball may be substituted for the
diaphragm, the compression of which in being pulled off will move the
air in the tube.
Any suitable apparatus for exhausting the air or forcibly blowing the
whistle may be placed on either the engine or the guard's van or in any
I then train

page_text: The means whereby I shut off communication as before described
consists simply of one or more slides or shutters which can be moved so
as to close the main tube at either side of a branch tube. This mode is
also applicable to pneumatic signalling for other purposes; and the
mode of coupling herein-before described is also applicable to connecting
pipes and tubes for other purposes.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Edwin Thomas Truman in the Great Scal Patent
Office on the 27th April 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWIN
THOMAS TRUMAN, of Old Burlington Street, in the County of Middlesex,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-seventh day of October, in the year of
our Lord One thousand eight hundred and seventy-three, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Edwin Thomas Truman, Her special
licence that I, the said Edwin Thomas Truman, my executors, adminis-
trators, and assigns, or such others as I, the said Edwin Thomas
Truman, 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
"IM-
Ireland, the Channel Islands, and Isle of Man, an Invention for
PROVEMENTS IN MEANS OR APPARATUS FOR EFFECTING INTERCOMMUNICATION IN
TRAINS, PARTLY APPLICABLE TO OTHER PURPOSES," upon the condition (amongst
others) that I, the said Edwin Thomas Truman, my executors or
administrators, by an instrument in writing under my, or their, or onc
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 Edwin Thomas Truman, do
hereby declare the nature of my said Invention, and in what manner the

page_text: same is to be performed, to be particularly described and ascertained in
and by the following statement thereof, that is to say :-
My Invention primarily relates to the use of tubes extending along
the train from carriage to carriage for enabling the passengers, guards,
and drivers to communicate with and even to talk to each other in case
of need. For a system of this description to be perfect the tubes of
adjoining carriages must be easy to couple together in making up a
train; the tubes and their connections between the carriages must be
perfectly air-tight; the branch tube in each compartment of the several
carriages must be closed in such a way that while the end may be
readily uncovered by a passenger, yet he cannot reinstate or replace the
cover to avoid identification; there should be distinct means. of com-
munication between the guard and driver, or between the front and rear
guards; and the whole arrangement must be simple and inexpensive..
My Invention consists in the combined means or apparatus herein-
after described for fulfilling the requirements above indicated; also in
an improved mode of forming the tube connections.
I carry along the top or at other convenient part of every carriage two
distinct tubes of gutta percha, or india-rubber, metal, or other suitable
material. The ends of these tubes extend beyond the end of the
carriage and terminate in connecting pieces on the adjoining carriages.
These connecting pieces must be so arranged that no matter which ends
of two carriages come opposite each other, the male connecting piece of
one carriage shall meet the female piece of the other, and vice versa.
For this purpose I provide each tube with a male piece at one end and a
female piece at the other, in such manner that the two male pieces of
the two tubes of the same carriage are diagonally opposite each other,
care being taken that all the carriages have the male picces in the samo
position, for instance, let the male piece be always at the right and the
female piece at the left, when a person faces either end of the carriage.
In this way it will be impossible for two male pieces or two female pieces
to meet each other.
The manner in which I prefer to form the tube connections is by
means of a collar or outer tube into which the ends of the two tubes to be
connected are inserted, the collar being then moved so as to bring the
ends of the two tubes close together and make a joint. In each end of
the collar two or more studs or pins are fixed, and on the outside of the

page_text: end of each of the tubes are two or more inclined planes or segments of
a screw of coarse pitch, those on one tube being right-banded and those
on the other being left-handed. When the ends of the two tubes are
inserted into the opposite ends of the collar the studs take behind the
inclined planes or screw segments on the respective tubes, and by then
giving a partial rotation to the collar the studs move up the inclined
planes, draw the tube ends tightly together, and thus make the joint.
The tube ends should be ground or faced so as to fit truly against each
other, and I prefer that one of them should be countersunk and the
other turned conical to fit in it.
In some cases I form the inclined planes or screw segments on one
of the tubes only, the collar in this case being carried by the other tube
on which it can be turned within a given limit.
To prevent either of the tubes rotating with the collar the end of one
of them may be furnished with one or more projecting pins to take into
corresponding holes formed in the end of the other.
For the purpose of enabling the collar to receive the partial rotation
necessary for connecting and disconnecting the tubes I fit a handle or
lever arm thereto, which handle or arm may be weighted. The weighted
arm is raised before the tubes are brought together, and may then be
left free, the weight being sufficient to partially rotate the collar so as to
bring and to keep the tube ends tightly together.
The mode of coupling above described is applicable to connecting
pipes and tubes for other purposes.
The tube of the last carriage of the train should be connected to
tubes in the guard's van, and those of the first carriage to tubes leading
to a position near the engine driver, or to tubes in the front van, when
there is one, or the tubes may terminate in any other suitable part of
the train.
From one or both of the tubes of every carriage I carry branch tubes
into the several compartments of the carriage, and I close the end of
each branch tube with a diaphragm of india-rubber or other suitable
material, or with any other air-tight device which may readily be torn
off or burst or moved but cannot again be replaced or reinstated by a
passenger, and I prefer to arrange the closing device in such manner
that the very act of tearing it off or bursting it shall move the air in the

page_text: "corresponding tube, and thereby act upon a whistle in the guard's van
or wherever the main tube may finally terminate. In any case as soon
as the closing device is torn off or burst, and the whistle (when such is
used) in the guard's van removed the passengers in the compartment
can talk with the guard.
The guard and driver or the front and rear guards can at all ordinary
times freely communicate with each other through either of the main
tubes, and when their communication through one tube is interfered
with by a passenger opening a branch tube, their means of com-
munication through the other main tube still remains intact.
The means by which the branch tubes may be so closed that the very
act of opening them moves the air in the main tube as before-mentioned,
may consist simply of an elastic diaphragm placed over the mouth
piece of the branch tube, and provided with a ring or handle for pulling
it off the mouth piece; when the ring is pulled the diaphragm will
stretch before leaving the mouth piece, and thereby produce a sufficient
movement of the air in the tube to sound the whistle, which whistle I
prefer to make double-acting so that it will sound both when the air is
moved into the tube and out of the tube at that end; or the ring may
dispensed with, in which case the diaphragm must be burst by being
pushed inwards, and this action will move the air in the tube sufficiently
to sound the whistle; or an elastic ball may be substituted for the
diaphragm, the compression of which in being pulled off will move the
air in the tube.
bc
Any suitable apparatus for exhausting the air or forcibly blowing the
whistle may be placed on cither the engine or the guard's van or in any
other part of the train.*
To enable a passenger to shut off communication between his own
carriage and either end of the train so as to compel all the sound to
travel to the other end I employ one or more slides or shutters which
can be moved so as to close the main tube at either side of a branch
tube. These slides or shutters may be plain pieces fitted in openings in
the side of the tube and capable of being pushed in or drawn out as
required. Or the branch tubes may form the slides or shutters; in this
case the branch tube is fitted in a tubular socket depending from the
main tube, it is closed at its inner end and has at its side near the inner
end an aperature corresponding with the sectional area of the main tube.

page_text: This sliding tube in its normal position is drawn out so that its inner
and closed end is exactly at the inner end of the tubular socket.
Direct communication through the main tube is thus open while the
closed end of the sliding tube shuts off communication with the mouth
piece; but by pushing in the sliding tube so that its closed end comes
against the further side of the main tube, and by then turning the
sliding tube on its axis so as to bring the aperture in the slide thereof in
a line with the required side of the main tube communication with the
desired end of the main tube is opened, communication with the other
end of the same being simultaneously closed. The inner end of the
sliding tube should be curved so as when pushed inwards to fit accurately
against the inner face of the main tube. To allow the longitudinal and
axial movements of the sliding tube in the tubular socket as above
described to be effected with ease and precision I provide the tube and
socket with a bayonet joint.
And having now described the nature of my said Invention, and in
what manner the same is to be performed, I declare that I claim,-
1st. The combined means or apparatus herein-before described for
effecting intercommunication in trains.
2nd. Constructing joints or couplings for train intercommunication
tubes and for other pipes or tubes, substantially as herein-before