IMPROVEMENTS IN TELEGRAPHIC APPARATUS
Year: 1873

page_text: LETTERS PATENT to Sir Samuel Canning, of Great Winchester Street
Buildings, in the City of London, and Edgar James Mayor, of
Bradmore Park Terrace, Hammersmith, in the County of Mid-
dlesex, for the Invention of "IMPROVEMENTS IN TELEGRAPHIC
APPARATUS."
PROVISIONAL SPECIFICATION left by the said Sir Samuel Canning
and Edgar James Mayor at the Office of the Commissioners of
Patents, with their Petition, on the 26th July 1878.
We, Sir SAMUEL CANNING, of Great Winchester Street Buildings, in
the City of London, and EDGAR JAMES MAYOR, of Bradmore Park
Terrace, Hammersmith, in the County of Middlesex, do hereby declare
the nature of our said Invention for "IMPROVEMENTS IN TELEGRAPHIC
Apparatus,” to be as follows :-
This Invention relates more especially to pneumatic telegraphic
apparatus suitable for use in conveying signals in houses and manu-

page_text: factories, on board ships, on railways, in railway trains, and for other
like purposes.
According to one arrangement of pneumatic telegraphic apparatus it
is proposed to employ for effecting the compression of the air necessary
for transmitting signals through tubes, a cylinder and piston com-
municating with the transmission tube or tubes, the mouths of which
we prefer to make conical. Outside and concentric with this cylinder
and piston there., is a second cylinder and piston of annular form, the
annular piston being connected with the internal piston, so that the two
shall move together.
One or more holes are made in the sides of the inner cylinder, so as
to communicate with the annular cylinder, and other holes are made in
the annular cylinder communicating with the atmosphere. These holes
serve to equalize the temperature of the air in the cylinder and trans-
mission tube or tubes, as when the apparatus is at rest there is a free
communication between both the cylinders and the atmosphere. On
depressing or forcing inwards the pistons the air is compressed in the
inner and outer cylinders, and simultaneously, but any leakage that may
take place past the sides of the piston in the inner cylinder is counter-
acted by the pressure of the air in the outer cylinder, and consequently
the air that would have escaped from the inner cylinder is forced through
the transmission tube or tubes.
By this Invention the size of the apparatus for a given distance of
signalling may be considerably reduced. Or in lieu of using inner and
outer cylinders, each provided with its piston, two tubes may be a
employed, the one sliding within the other like the joints of a telescope,
air holes being provided for establishing a free communication with the
atmosphere when the tubes are drawn fully out, but which communi-
cation is closed on forcing inwards one of the tubes in the act of com-
pressing the air to force it along the signal tubes.
Another arrangement of apparatus consists of a mode of constructing
a pneumatic indicator or telegraphic instrument in such a way that the
order shutters or tablets shall be held in the required position without
depending on any valves or stop-cocks, or on the maintenance of any
pressure in the pipes.
Also of such an arrangement of the air-compressing cylinders for
making the above, as that one movement of the lever of the communi-

page_text: cator shall cause an inflation and collapsing action in different air
chambers of the indicator at the same time.
Also in so arranging the bell and shutter action of the indicator, as
that one air chamber shall give the movement necessary, both to ring
the bell and display the signal, thereby giving an increase of power by
reason of the air not having two air chambers to expand into as
heretofore.
The principle upon which this instrument works is as follows :-In
the transmitting instrument are fixed a number of small brass tube
cylinders, two of which are in connection with each order that is shown
on the indicator. Thus a 5 order instrument has 10 of these cylinders
and 10 tubes, a 7 order instrument 14 cylinders and 14 tubes. These
cylinders are fixed in a vertical or in a horizontal position, and can
therefore be worked either by pulling the levers towards the operator or
by pressing them down.
In each cylinder of these pairs of cylinders works a piston attached to
a common piston rod moved in either direction by a lever, so that when
one cylinder is compressing the air in one tube the other is exhausting
the air from the other tube. These tubes are led from any convenient
place in the box of each cylinder tubes, and communicate with the indi-
cating instrument, where they are severally attached to a pair of elastic
or other air chambers, and light lever is fixed on a pivot, and terminates
at one end in a small plate, which when the instrument is not being
used rests against the under side of one of the air chambers. On the
other end of this lever there is fixed an indicating tablet, the upper part
of which is opaque, and the lower transparent: On the latter part is
written the order; but this arrangement when the instrument is at rest
only the upper part of the tablet will be visible through an opening in
the outer casing of the instrument. On the air chamber above this
lever being inflated one end of the lever will be depressed, and the other
end carrying the tablet will be raised, and with it the indicating tablet,
the upper part of which will be raised above the opening, whilst the
lower or transparent part will be rendered visible through it, thereby
giving the order, which is maintained in its position as follows:-On
the inner end of the lever being depressed it comes in contact with a
catch on.a bell crank. This movement fixes the lever so that the indi-
cating tablet cannot fall till released from the catch. It is released by

page_text: the inflation of the second and lower air chamber, which forces up one
arm of the bell crank, thereby drawing back the catch from the end of
the lever, now the tablet end of the lever being heavier than the other
end it at once falls, and with it the indicating tablet, which in that
position only shews its upper or blank and opaque portion through the
outer casing at the opening.
It will be seen that if the two pipes or tubes are connected with the
two air chambers, on moving the actuating lever either backwards or
forwards one of the air chambers will be inflated, the other exhausted or
collapsed, thus causing the indicating apparatus to work as above
described. If the operator wishes to give a signal he pulls over the
actuating lever and forces the air from one of the cylinders into the
corresponding air chamber; this causes the indicating tablet to be
shewn through the opening; if the operator now wishes to discontinue
the signal he pushes the actuating lever back in the opposite direction, :
thus drawing the air out of the corresponding tube or pipe, and causing
the air chamber in connection therewith to collapse by the same
movement, forcing the air out of the opposite cylinder into the corre-
sponding pipe, and inflating the air chamber connected therewith, thus
setting free the catch and the order, tablet, which now only shows its :
blank face through the opening.
If it is desired to obtain greater sending power than is obtained from
the before-mentioned cylinders, as for instance, in working through very
long distances, the double cylinder with two pistons herein-before
described, or the telescopic tubes without pistons can be employed in s
place of the two ordinary cylinders. It is necessary in practice that a
bell should be rung in the indicating instrument on an order being
given. This is done in this instance by fixing on the lever carrying the
tablet an arm, so that the lever being depressed the arm presses against
a striker fixed on a spring, which it draws back a certain distance and g
then releases, thereby striking a gong. When the tablet end of the
lever falls on the signal being released, the arm passes the striker by
lifting a detent which falls into its place again as soon as the arm has
passed without moving the striker, and the bell is then ready for another
signal.
g

page_text: Tablets Can De шxed in the same casing and
tablets has its individual bell. If it be thought desirable to give greater
distinctness in the communicator as to which of the orders has been sent,
shutters or discs can be so arranged and attached to the levers of the
communicators that they may mask or unmask the order plates, as may
be most convenient.
This Invention further comprises an improved pneumatic bell for long
distances. Hitherto it has not been found practicable to ring bells on
the pneumatic system through such long distances as 1,000 or 1,500 feet,
owing to the length of time the air takes to travel, the loss of density it
undergoes before reaching the bell, and the large quantity of air that
has to be forced into the tubes to overcome this loss of power, These
objections are mostly done away with in this bell, in which the work the
air has to do at the bell end of the pipe is reduced to a minimum, little
air being required. An order shutter can also be shown without adding
to the work the air has to do; another advantage is, that there are no
springs or wheelwork, and few parts to get out of order. In this
apparatus a fixed gong is used, and a striker supported on a standard,
which striker is furnished with two arms, and with a small handle, all
fixed together and moving freely in a bearing in the top of the standard.
One arm is provided with a weight, so that if the striker be turned up by
moving round the handle till the opposite arm is in contact with a stop,
it will be seen that as soon as the handle is released the weight will fall,
and in so doing will bring over the striker, which continues to fall till it
strikes the gong.
To enable the striker to be held ready for striking till it is desired to
give a signal, a bell crank is fixed at such a distance from the standard
that on lifting-the striker into the position ready for striking one of the
arms-will-engage into a catch on the bell crank which holds it fast.
Under the other arm of the bell crank there is placed a small elastic or
other air chamber connected with the tubing coming from the room or
building from which the signal is sent, where it is attached to an ordinary
push button or india-rubber bag for forcing the air through the tube.
On pressing this push button or bag the air is driven through the
tubing, thereby inflating the bag, which immediately lifts one arm of
the ball crank and sets free the arm of the striker from the catch; the
striker at once falls as above described. On the striker there is fixed an
order tablet, on which can be written any name or number, so that on

page_text: the striker falling this tablet falls with it, and appears behind an opening
which is cut in the outer casing of the instrument, thus indicating which
gong has sounded.
To reset the order tablet the handle is turned back by the person
receiving the order, as before described.
When several of these gongs are placed in one case, a complete set of
orders can be given, and by the use of two of these instruments persons
in different rooms or buildings can communicate with each other through
distances hitherto unattained by the pneumatic system.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Sir Samuel Canning and Edgar James Mayor, in
the Great Seal Patent Office on the 26th January 1874.
•
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, Sir
SAMUEL CANNING, of Great Winchester Street Buildings, in the City
of London, and EDGAR JAMES MAYOR, of Bradmore Park Terrace,
Hammersmith, in the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-sixth day of July, in the year
of our Lord One thousand eight hundred and seventy-three, in the
37th year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto us, the said Sir Samuel Canning and Edgar James
Mayor, Her special license that we, the said Sir Samuel Canning and
Edgar James Mayor, our executors, administrators, and assigns, or such
others as we, the said Sir Samuel Canning and Edgar James Mayor,
our executors, administrators, or 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 TELEGRAPHIC APPARATUS," upon the condition (amongst
others) that we, the said Sir Samuel Canning and Edgar James Mayor,
our executors or administrators, by an instrument in writing under our
hands and seals, or under the hand and seal of one of us, should
.

page_text: 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 we, the said Sir Samuel Canning and Edgar
James Mayor, do hereby declare the nature of our said Invention, and
in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement, reference
being had to the accompanying Drawings and to the letters and figures
marked thereon, that is to say :—'
Our said Invention relates more especially to pneumatic telegraphio
apparatus suitable for use in conveying signals in houses and manu-
factories, on board ships, on railways, in railway trains, and for other
like purposes..
And in order that our said Invention may be fully understood, we shall
now proceed more particularly to describe the same, and for that
purpose shall refer to the several Figures on the annexed Sheet of
Drawings, the same letters of reference indicating corresponding parts
in all the corresponding Figures.
One arrangement of pneumatic telegraphio apparatus which we
propose to employ for effecting the compression of the air necessary for
transmitting signals through tubes consists of a cylinder A and
piston B, shown full size in vertical section at Fig. 1 of our Drawings,)
communicating with the nozzle or nozzles O, the mouths of which we
prefer to make confcal, as shown, and to which nozzle or nozzles we
connect the ordinary transmission tube or tubes. Outside and con-
centric with this cylinder and piston there is a second cylinder D and
piston E of annular form, the (annular piston E being connected at F
3 with the internal piston B so that the two pistons shall move together
in their respective cylinders.
In lieu of the ordinary valves and springs one or more vent holes a, a,
are made in the sides of the inner cylinder A, so as to communicate with
the annular cylinder D, and other vent holes b, b, are made in the
5 annular cylinder communicating with the atmosphere. These holes a
and 6 serve to equalize the temperature of the air in the cylinder A, and
nsmission tube or tubes, since when the apparatus is at rest or in the

page_text: condition shown in Fig. 1 there is a free communication between both
the cylinders A and D and the atmosphere. On depressing or forcing
inwards the pistons B and E the air is compressed simultaneously in the
inner and outer cylinders A and D, but any leakage that may take place
past the sides of the piston B in the inner cylinder A is counteracted by
the pressure of the air in the outer cylinder D, and consequently the air
that would have escaped from the inner cylinder is forced through the
nozzle or nozzles O to the transmission tube or tubes.
By this arrangement the size of the apparatus for a given distance of
signalling may be considerably reduced. In lieu of using inner and
outer cylinders each provided with its piston as herein-before described
and illustrated at Fig. 1, tubes may be employed (as shown in the full
sized section at Fig. 2) sliding the one over the other like the joints of
a telescope. A is a tube corresponding to the cylinder A in Fig. 1,
previously described. B is an inner tube closed at its inner end and
sliding air tight or nearly so within the tube A, the said tube B
answering the purpose of the piston B in Fig. 1; 0 represents one of
the nozzles communicating with the usual transmission tube; D is an
outer tube secured at F to the inner tube B and sliding air tight, or nearly
so, over the tube A. Air holes a, a, are provided in the cylinder or tube A
for establishing a free communication with the atmosphere when the
tubes are drawn fully out, as shown in Fig. 2, but which communication
is closed on forcing inwards one of the tubes in the act of compressing
the air to force it along the signal tubes. The compressed air in the
annular space enclosed in the outer tube D serves to counteract or
prevent any leakage of air past the sides of the inner tube B as
described with reference to Fig. 1.
Another part of our said Invention consists of a peculiar construction
and arrangement of pneumatic indicator or telegraphic iustrument
which is represented (full size) in vertical section and corresponding a
plan at Figs. 3 and 4 respectively; Fig. 5 is a detail front or face view
of one of the shutters or tablets, herein-after referred to, detached,
and Fig. 6 is an elevation on a small scale of the exterior front of the
casing of the indicator with one of the orders displayed. This instru-
ment is constructed in such a way that the order shutters or tablets a
shall be held in the required position without depending on any
valves or stop-cocks or on the maintenance of any pressure in the
transmission tubes or pipes as herein-after described.

page_text: Our Invention further consists of such an arrangement of the air
compressing cylinders for working the above as that one movement of
the lever of the communicator or transmitting instrument (shown in
elevation and vertical section on a small scale at Figs. 7 and 8 respec-
tively) shall cause an inflation and collapsing action in different air
chambers in the indicator at the same time.
We also propose to so arrange the bell and shutter action of the
indicator as that one air chamber shall give the movement necessary
both to ring the bell and display the signal, thereby giving an increase
of power by reason of the air not being required as heretofore to expand
into two air chambers simultaneously.
The principle upon which this apparatus works is as follows:-In the
communicator or transmitting instrument (Figs. 7 and 8) are fixed a
number of small brass tube cylinders a, a³, each of which may be of the
construction shown at Figs. 1 and 2, or may consist of an ordinary
cylinder with a piston or plunger working therein, or in lieu of cylinders
and pistons collapsible chambers may be employed in pairs. In either
case each pair of cylinders or collapsible chambers is in connection with
each order shewn on the indicator, thus a 5 order instrument has 10 of
these cylinders and 10 tubes, a 7 order instrument 14 cylinders and
14 tubes.
These cylinders are fixed in a vertical position (as shown in Fig. 8), o
in a horizontal position, and in each cylinder of these pairs of cylinders
works a piston attached to a common piston rod, moved in either direc-
tion by a lever b, which may be made to rise and fall, as in Figs. 7 and 8,
or to work in a horizontal direction, according to the position of the
cylinders, so that when one cylinder a is compressing the air in one
tube o the other cylinder a³ is exhausting the air from the other tube c¹.
These tubes o, o³, are led from any convenient place in the base of each
) cylinder, and communicate with the improved indicating instrument
(Figs. 3 and 4) or with any other indicator of spitable construction.
Where our improved indicating instrument is employed the tubes c, o',
are severally attached to a pair of elastic or other air chambers d, d². A
light lever A is fixed on a pivot e, and terminates at one end in a small
5 plate, which when the instrument is not being used rests against the
under side of the upper air chamber d, as shown in Fig. 8. On the
other end of this lever there is fixed an indicating tablet g, g², the upper

page_text: h
part of which g¹ (see Fig. 5) is opaque, and the lower part 9 transparent.
On the latter part is written the order. By this arrangement, when the
instrument is at rest, the upper or opaque part only of the tablet will be
visible through an opening (Figs. 3, 4, and 6) in the outer casing B of
the instrument. When the air chamber & above this lever A is inflated
or expanded one end of the lever will be depressed, and the other end
carrying the tablet will be raised, and with it the indicating tablet, the
upper part of which will be raised above the opening (as shown by the
dotted lines in Fig. 3), whilst the lower or transparent part will be
rendered visible through such opening, thereby giving the order, which
order is maintained in its position in the following manner :-On the
inner end of the lever being depressed it comes in contact with the catch i
formed on the upright arm of a bell crank working on a pivot k. This
movement fixes the lever A, so that the indicating tablet cannot fall till
released from the said catch. It is released by the inflation of the second
and lower air chamber d³, which forces up the horizontal weighted arm¿¹
of the bell crank, thereby drawing back the catch i from the end of the
lever A, and as the tablet end of this lever is heavier than the other end
it at once falls, and with it the indicating tablet, which in that position
only shews its upper or blank and opaque portion through the outer
casing at the opening h.
It will be seen that if the two pipes or tubes c, c¹, are 'respectively
connected with the two air chambers d, d³, on moving the actuating
lever 6 of the communicator either upwards or downwards one of the air
chambers d or d' will be inflated at the same time that the other is
exhausted or collapsed, thus causing the indicating apparatus to work as
above described. When the operator wishes to give a signal he presses
down the actuating lever b, and forces the air from one of the cylinders a
into the corresponding air chamber d. This causes the indicating tablet
to be shewn through the opening. If the operator now wishes to dis-
continue the signal he pushes the actuating lever 6 in the opposite
direction or elevated it, thus drawing the air out of the corresponding
tube or pipe c, and causing the air chamber d in connection therewith
to collapse, and by the same movement forcing the air out of the opposite
cylinder a¹ into the corresponding pipe c³, and inflating the air chamber d
connected therewith, thus setting free the catch i, and restoring the
order tablet to its normal position, so that it shall only shew its blank
face g¹ through the opening h. When greater sending power is required

page_text: than can be obtained from cylinders of the ordinary construction, as for
instance, in working through very long distances, then the double
cylinder arrangement, with two pistons, herein-before described and illus-
trated by Figure 1, or the telescopic tubes without pistons, as shown in
Figure 2, can be substituted. It is necessary in practice that a bell
should be rung in the indicating instrument on an order being given ;
this is effected in this instance by fixing on the lever carrying the tablet
an arm A¹³, so that the lever on being depressed shall cause the arm A¹ to
act upon a striker 7 fixed on a spring m, which it draws back a certain
distance and then releases, thereby striking a gong O. When the tablet
end of the lever A falls, on the signal being released, the arm A' passes
the striker by lifting a hinged trigger or detent n, which falls into its
place against a stop pin as soon as the arm A¹ has passed without
moving the striker, and the bell or gong is then ready for another
signal.
Each pair of cylinders a, a³, in the communicator is connected with an
indicating arrangement, as herein-before described, and any number of
these cylinders and indicating tablets can be fixed in the same casing,
and each of these indicating tablets may have its individual bell, or one
bell may serve for two tablets. In applying this indicator for domestic
purposes, or to houses or offices, the air chambers d and o³ may be
inflated by using the ordinary press button. If it be thought desirable
to give greater distinctness in the communicator as to which of the
orders has been sent, shutters or discs can be so arranged and attached
to the levers of the communicators that they may mask or unmask the
order plates as may be most convenient.
Our Invention further comprises an improved pneumatic bell for long
distances, which is shewn in side elevation and corresponding end view
at Figures 9 and 10 respectively. Hitherto it has not been found
O practicable to ring bells on the pneumatic system through such long
distances as one thousand or one thousand five hundred feet, owing to
the length of time the air takes to travel, the loss of density it undergoes
before reaching the bell, and the large quantity of air that has to be
forced into the tubes to overcome this loss of power, these objections are
5 mostly obviated in our improved pneumatio bell, in which the work the
air has to do at the bell end of the pipe is reduced to a minimum, and
but very little air is required. An order shutter can also be shown

page_text: without adding to the work which the air has to accomplish. Another
important desideratum is that there are no springs or wheelwork and few
parts to get out of order. In this apparatus a fixed gong A is used, and
a striker B pivoted or centred at a on a standard C, which striker is
furnished with 2 arms b and c, and with a small handle or button d, all
fixed together and moving freely in the bearing on the top of the
standard. The arm 6 is provided with a weight e, so that if the striker
be turned up by moving round the handle or button & till the opposite
arm c is in contact with a stop ƒ on the standard the weight, on the
release of the handle, will fall, and in so doing will bring over the striker,
which continues to fall till it strikes the gong.
To enable the striker to be held ready for striking till it is desired to
give a signal a bell crank g, h, pivoted at is placed at such a distance
from the standard that on lifting the striker B into the position ready for
striking the arm c will engage into a catch k on the arm g of the bell-
crank, which catch holds it fast. Under the other arm of the bell
crank there is placed a small elastic or other air chamber 1, connected
with the tubing m from the room, building, or other locality from which
the signal is sent, where it is attached to an ordinary push button or
india-rubber bag for forcing the air through the said tube, or attached to a
a metal cylinder and piston. On pressing this push button or bag the
air is driven through the tubing, thereby inflating the air chamber 7,
which immediately lifts the arm h of the bell crank, and sets free the
arm c of the striker from the catch, the striker at once falls, as above
described. On the striker there is fixed an order tablet n, on which can 2
be written any name or number, so that on the striker falling this tablet
falls with it, and appears behind an opening which is cut in the outer
casing of the instrument, thus indicating which gong has sounded.
To reset the order tablet the handle or button d is turned back by the
person receiving the order, as before described.
"
When several of these gongs are placed in one case a complete set of
orders can be given, and by the use of two of these instruments persons
in different rooms or buildings can communicate with each other through
distances hitherto unattained by the pneumatic system.
3

page_text: said Invention, and the manner in which the same is or may be used or
carried into effect, we would observe in conclusion that what we consider
to be novel and original and therefore claim as the Invention secured to
us by the herein-before in part recited Letters Patent is,—
First. The combination of two or more concentric cylinders and pistons
or sliding tubes for the purpose of forcing air into or through pneumatic
tubes employed in connection with pneumatic telegraphic apparatus,
substantially as herein-before described and illustrated by Figures 1 and
2 of our Drawings.
Second. The arranging of the air compressing and exhausting
cylinders or their equivalent in the communicator in pairs, and the so
working the same as that one movement of the actuating lever shall
cause an exhausting and compressing action simultaneously in corres-
ponding air chambers in the indicator, substantially as and for the
purposes herein-before described and illustrated by Figures 7 and 8 of our
Drawings.
Third. The peculiar construction and arrangement of the indicator
whereby the order shutters or tablets are held in the required position
without being dependent on valves or stop-cooks or on the maintenance
of any pressure in the transmission tube, as herein-before described and
illustrated by Figures 3 and 4 of our Drawings.
Fourth. The combination of the lever arms A and A' with the single
air chamber d, whereby the inflation of one chamber shall sound a bell
or gong, and display the signal or order simultaneously, substantially as
herein-before described and illustrated by Figures 3 and 4 of our
Drawings.
Fifth. The peculiar construction and arrangement of pneumatic bells
for working through long distances, wherein a weighted striker is main-
tained in an elevated position ready for striking by a catch or trigger,
which is released to allow the striker to fall by the inflation of an air
chamber, substantially as herein-before described and illustrated by
Figures 9 and 10 of our Drawings.
Sixth. The combination of an order plate with the said striker when

page_text: herein-before described and illustrated by Figures 9 and 10 of our
Drawings.
In witness whereof, we, the said Sir Samuel Canning and Edgar
James Mayor, have to this our Specification set our hands and
seals, this Twenty-sixth day of January One thousand eight
hundred and seventy-four.