IMPROVEMENTS IN TELEGRAPHIC SIGNALLING INSTRUMENTS FOR TRANS- MITTING FIRE AND OTHER CALLS OR ALARMS
Year: 1876

page_text: LETTERS PATENT to William Henry Davies and Frederick Herbert William
Higgins, both of 17 and 18, Cornhill, in the City of London, for the Invention.
of "IMPROVEMENTS IN TELEGRAPHIC SIGNALLING INSTRUMENTS FOR TRANS-
MITTING FIRE AND OTHER CALLS OR ALARMS."
Sealed the 28th October 1876, and dated the 26th August 1876.
PROVISIONAL SPECIFICATION left by the said William Henry Davies and
Frederick Herbert William Higgins at the Office of the Commissioners of
Patents on the 26th August 1876.
WILLIAM HENRY DAVIES and FREDERICK HERBERT WILLIAM HIGGINS, both of
17 and 18, Cornhill, in the City of London. "IMPROVEMENTS IN TELEGRAPHIC
SIGNALLING INSTRUMENTS FOR TRANSMITTING FIRE AND OTHER CALLS OR ALARMS."
This Invention has for its object improvements in telegraphic signalling instru-
ments for transmitting fire and other calls or alarms. On the 15th July in the
year 1874, a Patent was granted to us for a call instrument, it was arranged that a
number of such instruments should be included in circuit on a single wire with one
receiving instrument. On this system the signals are produced by the interruption
of a current which otherwise flows constantly, and every interruption is recorded
on the travelling tape of a self-starting Morse instrument. The transmitting
instrument contains a spring which is wound by the movement of the commutator
handle, and runs down under the control of an escapement with a short pendulum
as soon as the handle is set free, thus causing a cam to rotate, which in so doing
breaks and completes the circuit in any pre-arranged manner, thereby producing
dots and dashes on the paper of the receiving instrument.
The object of our present Invention is to prevent any confusion of the signals
resulting from two or more operators manipulating their transmitting instruments
at the same time; heretofore it has been necessary that care should be taken to
avoid this. We now provide each transmitting instrument with a second clock-
work train which is wound by the action of the commutator handle simultaneously
with the main train. This second train when wound is locked by a pawl under the
control of an electro-magnet, but the train is released if there be any break in the
continuity of the current arising from the line being pre-occupied. If the second
train be thus pormitted to start into motion it locks the main train and delays the
Price Gd.1

page_text: transmission of the signal during the time it runs, which is. arranged to be just
longer than any signal in use on the line. If on the other hand the action of the
main train be not thus interfered with it starts into motion as soon as the commu-
tator handle is released and continues until it has run down, transmitting its proper
signal as heretofore. The main train when running also locks the second train of
its own instrument and prevents it acting after it has served its purpose, and it can
be arranged if necessary, also to maintain an earth connection which for the time
throws out of circuit all the transmitting instruments which are more distant than
itself from the receiving station.
In place of employing second trains, as above described, in the transmitting
instruments, these instruments may each be provided with a stop pawl controlled
by an electro-magnet, and which when the circuit is broken prevents the train
starting, although it may have been wound up by means of the commutator
handle.
The instrument is also provided with an apparatus in the nature of a polarized
relay which is actuated by the reversal of the current in the circuit, and puts the
electro-magnet previously mentioned out of circuit when the flow is in the reversed
direction
The receiving instrument immediately it starts into motion on the reception of a
signal from any transmitting instrument reverses the current in the circuit, which
serves, as already explained, to throw out of circuit the electro-magnets of the
transmitting instruments, and so to retain in inaction all of them but the trans-
mitter actually in possession of the line. At the end of the signal the receiving
instrument restores the flow of the current to its original direction
Indicators consisting of galvanometer needles with screens attached may be
included in the circuit to indicate the direction of the flow of the current, and con-
sequently whether or not the line is occupied.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Henry Davies and Frederick Herbert William Higgins
in the Great Seal Patent Office on the 26th February 1877.
WILLIAM HENRY DAVIES and FREDERICK HERBERT WILLIAM HIGGINS, both of
17 and 18, Cornhill, in the City of London. "IMPROVEMENTS IN TELEGRAPHIC
SIGNALLING INSTRUMENTS FOR TRANSMITTING FIRE AND OTHER CALLS OR ALARMS."
This Invention has for its object improvements in telegraphic signalling instru-
ments for transmitting fire or other calls or alarms. On the 15th July, in the
year 1874, a Patent was granted to us for a call instrument, it was arranged that a
number of such instruments should be included in circuit on a single wire with one
receiving instrument. On this system the signals are produced by the interruption
of a current which otherwise flows constantly, and every interruption is recorded
on the travelling tape of a self-starting Morse instrument. The transmitting
instrument contains a spring which is wound by the movement of the commutator
handle, and runs down under the control of an escapement with a short pendulum
as soon as the handle is set free, thus causing a cam to rotate, which in so doing
breaks and completes the circuit in any pre-arranged manner, thereby producing
dots and dashes on the paper of the receiving instrument.
The object of our present Invention is to prevent any confusion of the signals
resulting from two or more operators manipulating their transmitting instruments
at the same time; heretofore it has been necessary that care should be taken to
avoid this. We now provide each transmitting instrument with a second clockwork
train, which is wound by the action of the commutator handle simultaneously with
the main train. This second train when wound is locked by a pawl under the
control of an electro-magnet, but the train is released if there be any break in the

page_text: Figure 1 is a front elevation; Figure 2 is a side elevation; and Figure 3 is a plan
of an apparatus constructed according to our Invention, and provided with two
clockwork trains.
a, a, is the frame of the instrument, it carries the axis b which can be turned
partly round by means of the handle c By so turning it a coiled spring attached
at one end to the axis and at the other end to the frame is wound up, and the axis
is retained by the pawl d taking into a ratchet upon the axis The pawl d is
carried upon a spur wheel e which gears with a pinion on an axis f, on which is
When the
also the escapement wheel g and the cam or contact making wheel h
spring is wound up the axis and the wheels upon it tend to revolve, and when
free they do so but at a speed which is regulated by the anchor escapement i which
engages with the escapement wheel g The escapement i is furnished with the
pendulous rod, on which a regulating weight is screwed, and also with an arm j,
which when running swings to and fro through a slit in the side of the cylinder ;
when this cylinder moves from the position in which it is shown in the Drawing
the first clockwork train becomes locked, and so long as it remains so no signal is
transmitted by the instrument. At the same time that the first clockwork train is
wound up, by turning the handle c a second similar train is also wound, and the
axis m on which is the escapement wheel of this train (unless it be locked) imme-
diately commences to revolve, and at once moves the slit in the cylinder Z into such
a position that the escapement i is unable to vibrate, and so the first train is pre-
vented from running. The axis m has a spur wheel upon it which gears with and
drives a pinion on the axis of the cylinder 1, and n is a long lever pawl taking into

page_text: a notch in the periphery of the cylinder m; it is drawn out by a spring o except
when the electro-magnet p being excited retains the pawl.
If the trains be wound for the purpose of signalling at a time when signals are
already passing through the lino from another source, these signals causing breaks
in the continuity of the current at once allow the lever pawl to be lifted, and the
second train commences to run; whilst it continues to run no signal is given by this
instrument, the signal being delayed during the time the second train takes to run
down, by which time the line will be clear. In a similar manner if the first clock-
work train starts first into motion it locks the second train
For this purpose a
circular groove is cut in the face of the cam wheel h, and a pin on the lever pawl n
enters this groove. At the point where the pin stands when the cam is at rest the
groove is widened so as to allow room for the pin to play, but when the cam moves
from this position the groove holds the pin and the lever pawl so that they cannot
move. There is also on the axis f another cam or contact making wheel, not shown
in the Drawings, it has but one notch in it which breaks contact at the time when
the cam h is at rest.
The connections of the instrument are as follows:-The line wire bringing the
battery current from the receiving station is connected with the contact spring g
which bears on the surface of the cam h, from whence the current flows through
the frame of the instrument to one end of the coil around the electro-magnet p, and
the other end of this coil is in communication with the line wire leading to
other stations beyond. The second cam or contact making wheel on the axis fhas
also an insulated spring which makes contact with it; this spring is insulated from
the frame of the instrument and is connected to earth. By the connection when
the signalling train is running the current passes direct to earth, the electro-magnet p
and all stations beyond being cut out of circuit.
'
Figure 4 is a plan; Figure 5 is a side view; and Figure 6 is an horizontal
section of an instrument constructed according to our Invention, in which but one
clockwork train is employed, the purpose served by the second train in the instru-
ment already described being here served by an electro-magnet and magnetized
tongue.
The clockwork train is arranged in the manner already described with slight
differences in the forms of the parts which the Drawings clearly show, as before the
cam or contact making wheel is marked 1, and the spring bearing upon it
the winding handle; in this case it is not fast on the axis, but when it is turned to
c is
9.
the left hand it carries the axis with it in consequence of a pawl mounted on a
piece f¹on the axis engaging with a notch in a disc which is formed with or is
fixed to the axis A coiled spring c² is.applied in connection with a handle to
cause it to return immediately the train has been wound, whether the train at once
commences to run down or otherwise. The handle when out of use rests against a
stop and there makes an electric contact, the purpose of which is herein-after
described. is an electro-magnet, which by means of the long lever, pawl, or stop n
locks the clockwork train substantially as before, except that in this case it operates
by coming directly into contact with an arm fixed upon the anchor escapement.
The piece f¹ on the axis fis so formed as to hold the lever pawl n up to the electro-
magnet so long as the axis f is running, so that when the clock work train has
commenced to run the lever pawl cannot interfere to stop it. 8 is a small electio-
magnet, between the poles of which is a small permanent magnet t is able to move,
being pivotted at its lower end. The upper end of the magnet t plays between two
adjusting screws, with one of which it makes an electric contact, the object of which 5
is herein-after stated. The pieces which carry the adjusting screws are insulated
from the frame of the instrument.
The electric connections of the instrument are as follows:-The battery current
from the receiving station passes first to the small electro-magnet 8, after traversing
the coils of this magnet is also passes through those of the magnet p, and so to the 5
insulated stop r, whence when the handle is in contact with the stop it passes by
the handle to the frame of the instrument, and so to the cam or contact making

page_text: wheel h, and onwards through the contact spring 9 to the line leading to other
instruments in the circuit beyond The magnetized tongue t is connected between
the two electro-magnets 8 and p, and one of the screw stops against which it can
rest is connected with the stop 7 against which the handle rests.
The operation of sending a signal is as follows.-The movement of the handle c
supposing the line to be clear breaks the continuity of the circuit, and so causes the
instrument at the receiving station to start into motion at the same time the train at
the signalling station commences to run. The receiving instrument almost imme-
diately reverses the direction of the battery current, causing the small magnets & of
all the instruments to move over from one stop to the other, this throws all the
electro-magnets p out of circuit or rather short circuits them, as also the handles c;
this locks all the clockwork trains except that at the sending station, because this
has already commenced to run. The rotation of the cam h produces breaks in the
circuit which are duly recorded at the receiving station. The receiving instrument
having run its appointed time and received the signal stops, and immediately before
doing so it again reverses the current, the magnets s at all the sending stations
then fall over to their other stops, and every thing is then in the same state as at
the commencement. If any attempt has been made to signal from another station,
this signal which had previously been stopped will now be delivered, the electro-
magnet p being again excited so as to draw forward the lever pawls or stops n.
It will be observed that the movement of any of the handles c at the time that a
signal is in course of delivery does not cause any break in the continuity of tho
circuit, a separate line for the current having at this time boon established by the
magnetized tongues 8.
In connection with these instruments we, as already mentioned, place indicators
on the circuit to show when the line is occupied; these indicators are simply needles
surrounded by coils and carrying screens suitably inscribed. The change in the
direction of the current throws over the needle from one side to the other, and
brings into sight the screen which it is desired to exhibit.
Having thus described the nature of our said Invention, and the manner of per-
forming the same, we would have it understood that we claim, our improvements
substantially as herein described, by which in the use of telegraphic signalling
instruments for transmitting fire and other calls and alarms the signals from the
different signalling stations are prevented from interfering the one with the
other.
In witness whereof, we, the said William Henry Davies and Frederick Herberb
William Higgins, have hereunto set our hands and seals, this Fifteenth day
of February, in the year of our Lord One thousand eight hundred and
W*. HENRY DAVIES. (L.S.)
F. H. W. HIGGINS.
(L.S.)