IMPROVEMENTS IN SPEAKING TUBES AND ELECTRIC BELLS FOR USE WITH PROVISIONAL SPECIFICATION
Year: 1880

page_text: LETTERS PATENT to George Jennings and Edward Grimstone Brewer, both of
Palace Road Wharf, Stangate, in the County of Surrey, for an Invention of
"IMPROVEMENTS IN SPEAKING TUBES AND ELECTRIC BELLS FOR USE WITH
PROVISIONAL SPECIFICATION left by the said George Jennings and Edward
Grimstone Brewer at the Office of the Commissioners of Patents on the
24th November 1880.
"
GEORGE JENNINGS and EDWARD GRIMSTONE BREWER, both of Palace Road
Wharf, Stangate, in the County of Surrey. IMPROVEMENTS IN SPEAKING TUBES
AND ELECTRIC BELLS FOR USE WITH THE SAME, APPLICABLE ALSO FOR OTHER
PURPOSES."
This Invention has mainly for its object to enable a person at any part of a
building, say, the basement or ground floor, to communicate through a speaking
tube with any one or other of a number of rooms on the several floors above, and
vice versa.
In the same
For this purpose a speaking tube is led up from the basement or ground floor to
the several floors above. This tube we call the "main." At each floor a branch
pipe is led off from the "main" which branch pipe we call the "local main." At
each junction of a "local main" with the "main," flap valves, or it might be a
single flap valve, are applied, by which either the passage through the main can be
closed and the passage through the local main opened, or vice versa.
way branches are led off from the local mains on each floor to different rooms on
such floor, and valves are similarly applied at the junctions of the local mains and
branches. Ordinarily the passage through the "main" is open from end to end
and the passages from it to the local mains closed, and similarly the local main is
open from end to end and the passages from it to the branches closed. The several
valves are normally held in proper position by light springs or weights to keep the
mains open and the branches closed, as above described.
Together with the above apparatus we combine electrical apparatus, by which
either a person at the end of any one of the branches can give a call signal to the
terminal end or the main pipe, and open communication from his branch speaking

page_text: tube to the terminal end of the main speaking tube, or vice versa, that a person at
the terminal end of the main speaking pipe can give a call signal to persons at the
end of any one or other of the branches and open communication through the
speaking tube with that branch. Preferably we effect these objects in the
following manner :-
Each flap valve is connected by a link with the armature of an electro magnet.
For one valve of each pair of valves at a junction, say, the valve for the main, the
link is connected to a short arm extending from the valve above the axis on which
the valve swings, whilst the other valve for the branch has the link connected to
it directly below its axis; thus if the electro magnets are side by side and both
magnets attract their armatures, the two valves are moved in opposite directions
and the valve on the main is closed, whilst that on the branch is opened.
From the copper pole of a battery a wire is led up through the bell apparatus
in the basement or ground floor, and from thence to the ends of the several
branches and coupled to one of the terminals of a contact apparatus at each
branch. From the other terminal of each contact apparatus a return wire is led
back through the coils of the magnets at the junction between the branch and the
local main, and coupled to a wire which passes to the coils of the magnets at the
junction between the local main and main, and thence to the main return wire to
the zinc pole of a battery.
A main wire from the copper pole and another main wire from the zinc pole are
led up through the building, and the branch copper and zinc wires on the several
floors are coupled to them.
Whenever any one at the end of any of the branches wishes to communicate
with the person at the terminal end of the main pipe, he causes the two terminals
of the contact apparatus at that branch to be brought into electrical connection
with one another and so completes a circuit.
When a circuit is so completed at the end of any one of the branches, the electro
magnets open the valve from the branch to the local main and from the local main
to the main, so that a free passage is opened through the speaking tube from the
end of that branch to the terminal end of the main, and at the same time the bell
at the terminal end of the main is caused to ring and the attention of the person
at that end of the main thereby attracted.
Preferably the contact apparatus is carried at the side of the mouth piece of the
speaking tube; the mouth piece is as usual carried by a short length of flexible
tube, and ordinarily hangs downwards; when however the mouth piece is raised
and inverted so that a person may speak through it, a small loose weight in the
form of a ring drops and closes together the sides of two springs which form the
two terminals of the contact apparatus, and thereby completes the circuit. In the
same way when the mouth piece is allowed to hang down the weight drops to its
former position and the circuit is broken.
When the person at the terminal end of the main speaking tube lifts the mouth
piece at that end of the tube to speak through it, a contact apparatus similar to
that just described at the side of his mouthpiece gives a shorter circuit to the
current from the battery than through the bell apparatus which calls his attention,
and conversation can then be freely carried on between the terminal end of the
main and the branch.
On the other hand in order to enable the person at the terminal end of the main
to open communication with any person at the end of one or other of the branches,
an electric bell is used in proximity to the end of each branch.
A wire is led from the main copper wire between the bell in the basement and
the battery to a finger contact, and from thence direct to the axis of an arm, which
on being turned presses on metallic plates arranged in a circle. The electric
current is transmitted along this arm to any one of the plates, and the current
from the copper pole travels from the plate by a wire led direct to the bell, and
thence to the coils of the magnet of that branch; the circuit is so completed by
the wire from the zinc pole, as stated above.

page_text: The bell at the particular branch is thereby caused to sound and continues to
sound until the person at the branch end depresses a finger key, and thereby
breaks the circuit through the bell, but will ring again upon his taking the finger
from the key should the person in the basement have any thing further to say; or
a single stroke bell can be fixed in place of the continuous action bell, which would
dispense with the key at the branch.
In place of the main speaking tubes being made, as hereinbefore described, with
a single branch only branching off from them at each point of junction, two branch
tubes might be led off from opposite sides of the main tube, and one end of the
coils of each of the two magnets for working the two branch valves be coupled to
the end of the coil of the magnet which works the valve of the main, so that
whenever a current is passed through the coils of either one or other of the
magnets for working the branch valves it will also pass through the coils of the
magnet for working the valve of the main, and act upon this valve without the
other branch valve being affected.
If the electric bells used with the speaking tube apparatus above described were
of the ordinary construction, the current putting them into action would be
repeatedly made and broken during the time the bells were ringing; this alternate
making and breaking of the circuit would cause the speaking tube valves to
rapidly flap to and fro, thereby not only making an objectionable noise but also
causing unnecessary wear; we therefore construct each electric bell apparatus in
such a manner that when the armature by which the bell hammer is carried is
attracted by its magnet, a contact is made by which the current passing through
the coils of the magnet is short circuited and cut off from the coils of the magnet,
so that instead of the current being broken the current continues uninterrupted;
in the same way when the armature is by a spring moved away from the magnet
the current continues through the short circuit until it can again pass through the
coils of the magnet.
To facilitate conversation being carried on through the speaking tubes, we in
some cases form the mouth pieces with a side tube branching from them, and
curved so as to bring its end opposite the ear of the person holding the mouth
piece up to his mouth, so that without shifting the mouth piece a person may either
listen or speak through the tube.
In order also to prevent currents of air passing through the speaking tubes and
causing inconvenience to any one holding the ear piece up to the ear to listen to
what is being said through the tube, we place a thin flexible diaphragm across the
passage to the ear piece to cut off all flow of air through it, and to increase the
volume of sound.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Jennings and Edward Grimstone Brewer in the Great Seal
Patent Office on the 24th May 1881.
GEORGE JENNINGS and EDWARD GRIMSTONE BREWER, both of Palace Road
Wharf, Stangate, in the County of Surrey. "IMPROVEMENTS IN SPEAKING TUBES
AND ELECTRIC BELLS FOR USE WITH THE SAME, APPLICABLE ALSO FOR OTHER
PURPOSES."
This Invention has mainly for its object to enable a person at any part of a
building, say, the basement or ground floor, to communicate through a speaking
tube with any one or other of a number of rooms on the several floors above, and
vice versa.
For this purpose a speaking tube is led up from the basement or ground floor to
the several floors above. This tube we call the "main." At each floor a branch
pipe or pipes is led off from the "main," which branch pipe or pipes we call the
"local maius." At each junction of a "local main" with the "main," flap valves,
or it might be a single flap valve, are applied, by which either the passage through
the main can be closed and the passage. through the local main opened, or vice
versa. In the same way branches are or may be led off from the local mains on
each floor to different rooms on such floor, and valves are similarly applied at
the junctions of the local mains and branches. Ordinarily the passage through
the "main" is open from end to end, and the passages from it to the local mains
closed, and similarly the local main is open from end to end, and the passages from
it to the branches closed. The several valves are normally held in proper position
by light springs or weights to keep the mains open and the branches closed, as
above described.
Together with the above apparatus we combine electrical apparatus, by which
either a person at the end of any one of the branches can give a call signal to the
terminal end of the main pipe and open communication from his branch speaking
tube to the terminal end of the main speaking tube, or vice versa, that a person at
the terminal end of the main speaking pipe can give a call signal to persons at the
end of any one or other of the branches for them to open communication through
the speaking tube with that branch. Preferably we effect these objects in the
following manner :-
a
Each Hap valve is connected by a link with the armature of an electro-magnet.
From one pole of a battery, say, the copper pole, a wire is led up, it may be
through the bell apparatus in the basement or ground floor, and from thence to the
ends of the several branches, and coupled to one of the terminals of a contact
apparatus at each branch. From the other terminal of each contact apparatus
return wire is led back through the coils of the magnets at the junction between
the branch and local main and coupled to a wire which passes to the coils of the
magnets at the junction between the local main and main, and thence to the main
return wire to the zinc pole of the battery. A main wire from the copper pole,
and another main wire from the zinc pole, are led up through the building, and the
branch copper and zinc wires on the several floors are coupled to them.
Whenever any one at the end of any of the branches wishes to communicate
with the person at the terminal end of the main pipe, he causes the two terminals
of the contact apparatus at that branch to be brought into electrical connection
with one another and so completes a circuit. When a circuit is so completed at
the end of any one of the branches the electro magnets open the valve from the

page_text: branch to the local main and from the local main to the main, so that a free
passage is opened through the speaking tube from the end of that branch to the
terminal end of the main, and at the same time the bell at the terminal end of the
main is caused to ring and the attention of the person at that end of the main
thereby attracted.
Preferably the contact apparatus is carried at the side of the mouth piece of the
speaking tube; the mouth piece is as usual carried by a short length of flexible
tube and ordinarily hangs downwards; when however the mouth piece is raised
and inverted so that a person may speak through it, a circuit is completed, as herein
after described. In the same way when the mouth piece is allowed to hang down
the circuit is broken.
When the person at the terminal end of the main speaking tube lifts the mouth-
piece at that end of the tube to speak through it, a contact apparatus, similar to
that just described at the side of his mouth piece, gives a shorter circuit to the
current from the battery than through the bell apparatus, which had previously
called his attention, and so stops the bell from ringing, and conversation can then
be freely carried on between the terminal end of the main and the branch.
On the other hand, in order to enable the person at the terminal end of the main
to open communication with any person at the end of one or other of the branches,
an electric bell is used in proximity to the end of each branch, and can be set in
action by the completion of an electric circuit effected by depressing a finger
contact apparatus, as herein after described, or in other suitable manner.
If the bell at the particular branch is a continuous action bell it will continue
to sound so long as the circuit is completed by the depression of the finger key in
the basement, or should the person in the basement have anything further to say
he must again depress the key.
In place of the main speaking tubes being made, as herein before described,
with a single branch only branching off from them at each point of junction, two
branch tubes might be led off from opposite sides of the main tube, and three
separate valves be used, one for the main and one for each of the branches, and
one end of the coils of each of the two magnets for working the two branch valves
be coupled to the end of the coil of the magnet which works the valve of the main,
so that whenever a current is passed through the coils of either one or other of the
magnets for working the branch valves it will also pass through the coils of the
magnet for working the valve of the main, and act upon this valve without
the other branch valve being affected.
If the electric bell used in the basement with the speaking tube apparatus above
described were a continuous action electric bell of the ordinary construction, the
current putting it into action would be repeatedly made and broken during the
time the bell was ringing; this alternate making and breaking of the circuit would
cause the speaking tube valves to rapidly flap to and fro, thereby not only making
an objectionable noise but also causing unnecessary wear; we therefore construct
this electric bell apparatus in such a manner that when the armature by which the
bell hammer is carried is attracted by its magnet, a contact is made by which a
continnous current passing through the coils of the magnet is short circuited and
cut off from the coils of the magnet, so that instead of the current being broken
the current continues uninterrupted; in the same way when the armature is by
a spring moved away from the magnet the current continues through the short
circuit until it can again pass through the coils of the magnet.
To facilitate conversation being carried on through the speaking tubes, we in
some cases form each of the mouth pieces with a side tube branching from it, and
curved so as to bring its end opposite the ear of the person holding the mouthpiece
up to his mouth, so that without shifting the mouthpiece, a person may either
listen or speak through the tube.
Having thus described the nature of our Invention, we will proceed to describe
more fully the manner of performing the same."

page_text: At Figure 1 of the Drawings we have shown as an example a vertical section of
a house fitted up with a system of speaking tubes arranged in the manner above
described. In this Figure A is the main speaking tube led up from the basement
or ground floor to the several floors above. Below each floor the "main" pipe A is
connected at X with the bottom of a closed valve box B, shown in vertical section
on a larger scale at Figure 2, and a continuation of this pipe is led off at Y from
the top of the box, as shown in this Figure. From the top of the box is led off
at Z another pipe C, which we call the "local main;" this pipe is coupled to the
inlet X of another similar valve box, which for convenience we place on end. A
continuation of the local main C is carried on from the exit Y of the valve box to
any room on that floor, whilst a branch pipe D is led off from the exit Z to another
room.
In each valve box is a swinging valve E coupled, as shown by a link to the
armature F of an electro magnet G. The armature is carried by a spring H which
holds it away from the magnet when the magnet is not attracting it. When the
armature is thus held away from the magnet the valve will be in the position
shown by the dotted line in Figure 2, and the passage through the "main" will be
open. When however the armature is attracted by the magnet, the valve will be
turned into the position shown in full lines, and the passage through the "main" will
then be closed, and the passage to the branch opened. Preferably we affix to the
ends of the poles of the magnets small projecting pins of copper to keep the
armature from coming into actual contact with the poles of the magnet.
I (see Figure 1) is a battery, from one pole of which a main conducting wire J
is carried up to the several floors. K is a main return wire led back through a
bell apparatus, such as herein after more fully described to the other part of the
battery.
In the Drawings the main from one pole of the battery and all the other wires
coupled to it is shown by an ordinary dotted line, whilst the wires in connection
with the other pole are shown by a line of long and short dots.
At the extremity of each speaking tube is a length of flexible tubing L carrying
a mouthpiece M which hangs downwards, as shown in vertical section at Figure 3.
Through the tube are led two insulated wires; the ends of both wires are brought
to a contact apparatus N carried by the mouthpiece. For this contact apparatus
we use a short glass tube partially filled with mercury. The end of one wire is led
through one end of the tube, and of the other wire through the other end of the
tube. The tube stands vertically when the mouthpiece is hanging downwards, and
the mercury then in the bottom of the tube is not in contact with the end of the
wire which passes down through the top of the tube. When however the mouth-
piece is turned upwards by any person so that he may speak through it, the
mercury drops to the opposite end of the tube, and is then in contact with the ends
of both wires, and puts them in electrical connection one with the other. One wire
is led away to one of the main conducting wires from the battery, and the other is
led through the coils of the electro magnet of the valve apparatus at the junction
of that speaking tube with the main," or if the speaking tube is a branch, the
wire is led through the coils of the electro magnet of the valve apparatus at the
junction of the branch with the local main, and also through the coils of the local
magnet of the valve apparatus at the junction of the "local main" with the main,
and is then connected to the main return wire.
In this way when the mouth piece at the end of any speaking tube is turned
upwards a circuit is completed from the battery through the contact apparatus, and
acts upon such of the valves as required to open communication from that
speaking tube to the basement, and at the same time shuts off all communication

page_text: through the other tubes; the bell in the basement is likewise set ringing and calls
the attention of the attendant.
The attendant then lifts the mouthpiece at the terminal end of the main speaking
tube, and a contact apparatus carried by that mouthpiece then gives a shorter
circuit for the current than through the coils of the bell apparatus, as shown by
the wire connections in Figure 1, and so stops the ringing of the bell, and conver-
sation can then be carried on through the speaking tube between the terminal end
and the branch to which the "main" is then open. We would here state that in
the same way to that above described electrical contact apparatus may be combined
with the flexible tube carrying the mouthpiece of ordinary speaking tubes, so that
whenever it is turned upwards to speak through it shall complete an electric circuit
through a bell call apparatus at the opposite end of the tube, and so give a call
signal to the person at that end of the tube, and notify to him that some one desires
to speak to him through the tube.
Figures 4 and 5 show a vertical section and front view of the apparatus we
prefer to employ for enabling the attendant in the basement to give a call signal
to any person at the end of any one or other of the branches of the speaking
tube, but any other suitable electrical call apparatus might be used for the
purpose.
The apparatus is also shown in Figure 1. An electric call bell P is placed in
proximity to the end of each branch of the speaking tube. One end of the coil of
each bell apparatus is coupled up with one of the main conducting wires from the
battery, say, from the copper pole, whilst from the other another wire Q is led to
the basement and coupled to one or other of a number of pins R of the contact
apparatus shown at Figures 4 and 5. Opposite the head of each pin R is a press
button S which is ordinarily held away from the head of the pin R by a coiled
spring T. Each of these springs is connected as shown with the copper pole of the
battery. When any one or other of the press buttons is pressed inwards it is
brought into contact with the head of the pin R which is opposite to it, and
completes a circuit through the bell apparátus at the end of one or other of the
branches of the speaking tube, and causes the bell to ring.
Figure 6 shows a section of the electric bell apparatus which we use in the
basement. The armature O is held away from the poles of the magnet by a spring.
On the back of the armature is fixed a light spring O' which when the armature
is drawn towards the magnet comes against a metallic pin 02. This pin is con-
nected by a wire with one terminal of the wire coils of the magnet, and the
armature is connected by another wire with the other terminal of the wire coils.
In this way when the armature is attracted by the magnet a short circuit is
provided for the current through the pin 02 and armature O.
The magnet is
thereby enfeebled, and the spring which carries the armature throws the armature
back away from the magnet. The current then again passes through the coils of
the magnet, and the armature is again attracted, and so on continuously as long as
as a current is passing. Electric bell apparatus constructed in the above manner
is applicable for use for a variety of other purposes.
As will be seen by the Drawings, we form the terminals of the several speaking
tubes with two branches, one to which the ear is to be applied for hearing any
message spoken through the tube, the other for holding up to his mouth for speaking
through. This arrangement greatly facilitates the carrying on of conversation
through the speaking tubes.
Having thus described the nature of our Invention, and the manner of per-
forming the same, we would have it understood that we claim,-
First. The combination of a speaking tube with a tube or tubes branching out
from it, and with valve apparatus at the junctions for opening and closing the
communication between the main tube and branches, substantially as herein
described.
Second. The combination with a speaking tube having a branch tube or tubes

page_text: leading out from it of valves and electric apparatus for working the same at the
junction of the tubes, substantially as herein before described.
Third. The combined arrangement for short circuiting the call bell at the
terminal of the main speaking tube and so putting it out of action when the
attendant at that end of the speaking tube is ready to converse through it.
Fourth. The combined arrangement of electric bell, substantially as herein
before described with reference to Figure 6, whereby the electric circuit working
the bell is always maintained without interruption whilst the bell is ringing.
Fifth. The combination of electrical contact apparatus with the mouth piece of
a speaking tube, substantially as herein before described, so that when the mouth-
piece is turned upwards to allow of speaking though it an electric circuit shall be
completed through a call apparatus at the opposite end of the speaking tube, and
thereby give a call signal.
Sixth. Forming the terminals of speaking tubes with two branches, one to which
the air is to be applied and the other for speaking through, substantially as herein
before described.
In witness whereof, we, the said George Jennings and Edward Grimstone
Brewer, have hereunto set our hands and seals, this Twenty-third day of
May, in the year of our Lord One thousand eight hundred and eighty-one.
ANADAD TANNINAN