Electric Signalling Apparatus for use with a Network of Electrical Lines or Conductors.
Year: 1891

page_text: Dat: of Application, 10th Oct., 1891
Complete Specification Left, 20th Oct., 1891-Accepted, 13th Feb., 1892
PROVISIONAL SPECIFICATION.
Electric Signalling Apparatus for use with a Network of Electrical
Lines or Conductors.
We, Dr. LUDWIG VON ORTH, Engineer, and EMIL Breslaver, Manufacturer,
both of Berlin, Prussia, Germany, do hereby declare the nature of this invention
to be as follows :-
Our invention relates to a novel construction and arrangement of apparatus
whereby one or more predetermined signals can be sent from any point of a net
work of electrical lines to a station electrically connected with this net work. A
telephonic net for instance may thus be used for transmitting fire and other signals
in an automatic manner to a telephonic intermediate station and from thence to
another station. Any desired number of subscribers' telephonic apparatus within a
given district may be so connected up as to enable signals to be sent through a
single telephonic circuit common to the district. The construction and arrangement
of the apparatus is such that the telephonic traffic will not be impeded, as signals
cannot be sent off as long as the telephonic circuit is engaged for conversation. On
the other hand, from the moment when a signal has been sent off until the same has
been received, the telephonic circuit cannot be used for conversation. It is more-
over impossible to send off signals simultaneously from different subscribers offices
connected to the same circuit, so that any error which might otherwise occur at the
station by confounding the signals, is completely avoided. Furthermore the person
desiring to send off a signal can ascertain whether the signal has been transmitted
or whether the circuit is in use; in the former case the receipt of the signal is
acknowledged from the station.
In order to attain the above mentioned objects, an apparatus herein called a signal
transmitter is provided for a given district, and all the subscriber's offices in the
same district are connected therewith and provided with disengaging devices,
hereinafter called keys for electrically controlling it.
The accompanying drawing illustrates diagrammatically the apparatus and
connections in the case where two subscriber's offices say for example Nos. 294
and 923 are electrically connected with the signal transmitter, each office being
provided with two keys for giving two different signals, for instance "fire" and
"physician." Any desired larger number of subscriber's offices may be electrically
connected with the signal transmitter, in a similar manner and any desired number
of signals may be sent off as will be hereinafter more fully described.
The signal transmitter carries upon a shaft h driven by a train of ordinary
wheel-work, a number of conducting disce, the peripheries of which are provided
with projecting teeth corresponding to Morse letters; there is arranged for each
office connected with the signal transmitter a disc marked with the number of the
office, and for each signal to be sent a separate disc is provided.
In the apparatus shown there are therefore four discs the Morse letters of which
signify "294," "923," "fire" and "physician." Corresponding to each disc there
is a spring and an electromagnet E. When one of the latter attracts its
armature e, an insulated arm p secured to the armature presses the corresponding
spring into contact with the corresponding disc so that when this disc is revolved
by the shaft h and wheelwork, currents of relatively different lengths or duration
and corresponding to the Morse code, will be sent from the battery B to the rubbing
5 spring contact S. The arrangement of the inscription upon the discs is such that
the signs corresponding to the signals "fire" "physician" etc. are displaced the one
in relation to the other and in relation to the signs corresponding to the numbers so

page_text: that the called signals and the number of the subscriber's office will be sent off
consecutively.
The armatures e of the electro-magnets E corresponding to the numbered discs
are also connected to a second arm which in its position of rest is in contact with
a spring-n but which when the armature e is attracted bears against a spring m and
breaks contact with the spring n. The shaft h also carries an insulated disc O
formed with a recess d. In the rest position of this disc a boss secured to a
spring enters this recess. The circuit to the telephone station is then connected
by the spring and the screw to the telephone apparatus. When the shaft h
revolves, the spring is pressed against the screw y and by this means the circuit
to the telephone station is electrically connected with the spring S. At each
revolution, the spring v returns once to and in so doing touches a spring so that
for a moment the circuit is electrically connected with a relay R. The keys T
consist each of an electro-magnet, the armature of which is secured to a pivoted
arm that can be moved downward by the person desiring to send a signal, by means
of a ring fastened to a cord so that a contact a will be closed.
Assuming the signal "fire" has to be sent off from the subscriber's office 294:
the caller for this purpose pulls down the ring of the corresponding key T
thereby closing a circuit that passes from the local battery L B through the electro-
magnet E corresponding to the disc "fire" of the signal transmitter, then through
the electro-magnet of the key pressed down and the contact of the same, then
through the electro-magnet E of the disc No. 294, the corresponding lever land
spring n, thence through a contact piece arranged on the telephone hook, through
a contact g controlled by an electro-magnet K, and through the rest contact of the
relay R back to the local battery.
C
"
When a conversation is taking place over the line, this circuit will be broken
at H, and the electro-magnet E cannot therefore be excited at this time and the
ring will rise again under the action of a spring or weight thereby indicating that
the telephone line is in use. When however the telephone is suspended on the hook
at H, the circuit mentioned is closed and the armature t of the key T will remain
attracted. The electro-magnets E of the discs "fire" and "204 will attract
their armatures e and press the corresponding springs against the discs. The
armature e of the electro-magnet corresponding to disc 294 at the same time moves
the arm away from the spring n and into contact with the spring m whereby the
electro-magnet K is placed in the local circuit and excited. This electro-magnet
then attracts its armature thus breaking the contact at g, and by means of a pawli
releases the wheelwork for driving the shaft h of the signal transmitter. A signal
cannot now be sent from another subscriber's office because the circuit from the keys
at the other subscribers office No. 923 through the electro-magnet E of the
disc No. 923 and the corresponding spring n is broken at g. In addition to the
sigual "fire" the same subscriber's office No. 294 can also send off the signal
"physician." Whilst the apparatus is operating to send a signal it cannot be put
out of action by lifting off the telephone, i.e. by breaking the circuit at H.
As the shaft revolves, the spring bears against the screw y and currents then
pass from the battery B through the springs f, the discs "fire" and "294," the
shaft h, the spring S, the spring and the circuit to the intermediate telephone
station, where the indicator shutter will fall and thus call attention. As soon as the
attendant at this station has put in circuit his apparatus, he will hear the
characteristic ticking of the telephone diaphragm corresponding to the Morse
letters thereby indicating that a signal is being sent off and he can therefore in the
known way put the desired station in circuit, where the alarm signal arranged on
the telephone case will sound. The attendant at this station by taking off the
telephone will hear the ticking of the telephone diaphragm and by leading the
circuit through a Morse apparatus can receive the signal. He then sends into
the line from the central station a current which, as soon as the spring comes into
contact with the spring contact which takes place once for each revolution of the
disc o or the shaft h, flows through the relay R which then breaks the local circuit
z

page_text: the signa
anner the wheel work or mechanism for driving the shaft nor
ransmitter. A signal cannot now be sent from another subscriber's office
ecause the circuit from the keys at the other subscriber's office No. 923
hrough the electro-magnet E of the disc No. 923 and the corresponding spring n
3 broken at g. In addition to the signal "fire" the same subscriber's office
No. 294 can also send off the signal "doctor." It will be obvious that whilst
he apparatus is in action sending a signal it cannot be put out of action by
ifting off the telephone i.e. by breaking the circuit at H.
"
As the shaft h revolves, the spring r bears against the screw y and currents then
ass from the battery B through the springs, the discs "fire" and "294" the
haft h, the spring S, the spring and the circuit or line to the telephone station
where the indicator shutter will fall and thus call attention. As soon as the
attendant at this station has put in circuit his apparatus, he will hear the
characteristic ticking of the telephone liaphragm corresponding to the Morse
letters, thereby indicating that a signal is being sent off and he can therefore in
the known way put the special station in circuit, where the alarm signal arranged
on the telephone case will sound. The attendant at this station by taking off the
telephone will hear the ticking of the telephone diaphragm and by leading the
circuit through a Morse apparatus can receive the signal. He then sends into
the line from the central station a current which, as soon as the spring v comes into
contact with the spring contact z, which takes place once for each revolution of the
disc o or the shaft h, flows through the relay or electro-magnet R which is thereby
caused to break the local circuit at G. All the electro-magnets E of the signal
transmitter and also that of the key T then cease to be energized, the wheel work
or driving mechanism is arrested, and the armature t of the key T that was
operated springs upwards thus indicating that the signal has been duly received.
In the case of a fire signal, the attendant- at the central or ordinary telephonic
station or exchange can send the signal directly, by reversing, to the fire brigade
station by connecting the line to a conductor connecting the said telephone station
or exchange with the fire brigade station where a Morse apparatus must be provided.
to receive the signal. In this case the counter current to effect the stoppage of the
wheel work and serving to acknowledge the receipt of the signal may be sent off
directly from the fire brigade station instead of from the central office.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. Electric signalling apparatus for use with a net-work of electrical lines or
conductors in which keys T for the several signals to be transmitted are located at
the subscribers offices and are electrically connected with a signal transmitter
placed in the said net-work, the arrangement being such that by actuating either
of the keys T the circuit of a battery L B arranged at the signal transmitter will
be closed and driving mechanism will be disengaged and allowed to revolve a
shaft carrying signal discs, so that currents corresponding to the several signals
on the discs corresponding to the keys operated, will be sent off by the aid of
contact arms or springs from a battery B into the line and be received at a station
by suitable writing or receiving apparatus, substantially as hereinbefore described
with reference to the drawing.
2. The arrangement of signal transmitter with electro-magnets, contacts, keys
and connections substantially as described with reference to the drawings whereby
when one of said keys is actuated, electrical connections from the battery B to line
are formed only through the signal discs corresponding to the key actuated so that
coly signals corresponding to these discs will be sent off; the simultaneous
utilization of the same line for transmitting two signals from different subscriber's
offices or for transmitting a signal and for another purpose is prevented; and the
5 signalling person is informed whether his signal is being transmitted or the line is
otherwise in use.

page_text: 3. Apparatus of the kind referred to in Claim 1, provided with means such as a
relay or electro-magnet R so arranged that at each revolution of the shaft of the
signal transmitter, it will be connected for a short time to line in order that it may
be excited by a current sent from the station and thereby cause an interruption of
the current of the battery L B which excites the electro-magnets of the signal 5
transmitter and of the key, so that the driving mechanism will be stopped and the
armature of the key allowed to spring away and thus indicate that the signal
has been received, substantially as hereinbefore described with reference to and
shown in the drawing.
W. LLOYD WISE,
Per James G. Stokes,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicants.