AN IMPROVED NON INTERFERING FIRE ALARM TELEGRAPH SYSTEM APPLICABLE FOR USE AS A TELEPHONE SYSTEM
Year: 1885

page_text: I, LEWIS HARLAN M'CULLOUGH, a citizen of the United States of America,
residing at No 114, North fifteenth street in the City of Richmond, County of
Wayne, and State of Indiana, Inventor do hereby declare the nature of my said
invention for AN IMPROVED NON INTERFERING FIRE ALARM TELEGRAPH SYSTEM
APPLICABLE FOR USE AS A TELEPHONE SYSTEM, and in what manner the same is
to be perforined, to be particularly described and ascertained in and by the following
statement :-
This invention relates to means for obviating the possibility of sending in false
or confused signals in fire alarm telegraphy. That result is accomplished partly
by means of an arrangement of circuits, and partly by means of an improved
central office apparatus.
All or nearly all of the so-called non-interfering fire telegraph boxes and systems
now in use, or proposed for use, have been carefully examined and not one yet
found that accomplished the result aimed at. In every case, it would either
happen that two boxes pulled or rung in at the same time would both operate and
so produce a false or confused signal, or else there would be one or more moments
of time after one was rung in and before it had ceased to operate, when a second
box could also be operated and produce a like false or confused signal.
It is just this possibility which renders all or most of the existing non-interfering
systems, so-called, inoperative for the purpose designed; since the possibility, though
perhaps remote, may be realized at just the most dangerous crisis. The most
ordinary fire may become dangerous by reason of the confused operation of the
systems mentioned.
A system has been devised which is absolutely non-interfering and which, by
being so, removes the last existing danger of false or confused signals in fire
telegraphy. Moreover, any signal box in connection with the system may be used,
and with slight changes, the ordinary fire telegraph system now in use, can be
converted into an absolutely non-interfering system.
.')
In the drawings which accompany and form a part of this specification-
Figure 1 is a front elevation of a dial and dial box which together with their
immediate connections constitute my central office apparatus;
Figure 2 is a vertical section through the dial and the box;
Figure 3 is a plan view of a section through line x-x in Fig. 2; and
:

page_text: In Figs. 2 and 3, the size of the magnet is exaggerated for the sake of clearness,
and for the same reason the number of box-magnets is reduced in Fig. 4.
Referring to Figs. 1, 2 and 3, A, is a dial having around its edge numerals,
as 7, 9, 13, etc, representing the numbers of fire alarm signal boxes. Opposite each
numeral is an oblong slot whose longitudinal diameter is substantially at right
angles to that radius of the dial which passes through the center of the slot. A
hand or pointer B, which normally tends to move in the direction of the arrow
under the influence of the spring b, is 'mounted on the shaft C of the dial, and
held from turning by the stop d, as shown. The stop d is attached to the
armature D, pivoted at e behind the dial, and is held out so as to engage with the
pointer B by the spring f. The armature D is operated by the electro magnet E,
attached to the back of the dial box. In the same circuit with the electro
magnet E, is a second electro magnet F, which is attached to the front part of the
dial box. Its armature lever H is pivoted at g,.and has no retractile spring, but is
kept in any position in which it is placed (normally away from the core of the
magnet F) by the force of the spring h, pressing the extension of the armature
lever H, against one end of the slot a in the dial face. The extension k is loosely
pivoted to the armature lever H at 7, and is located substantially at right angles to
the armature lever. In pressing the extension k against one end of the slot a, the
spring h also presses it against the platinum point n on the conducting arm m,
attached to the dial box (See Figs. 2 and 3) The shaft C is connected through
engine houses Y, (see Fig. 4) or bell towers, or both, to one pole of a battery W.
The other pole is connected through a signal box with the binding post p, on
the dial box.
The circuit within the box is from binding post p, by wire 2, to extension k, to
the platinum point n and arm m, by wire 5 to electro magnet F, by wire 6 to
electro magnet E, by wire 7 to stop d, to pointer B, and shaft C.
There are as many binding posts p and magnets F as there are signal boxes in
the system, and the number of signal boxes will usually correspond to the number
of slots in the dial, less one, although the dial may be constructed to have several
more slots than there are signal boxes, to provide for future needs or contingencies.
The magnet E, which actuates the stop d, is common to all the circuits, the wire
from every magnet F being joined to the wire 6 which runs to the magnet E, at
some convenient point as r..
The spring 6 is made stronger than the spring & for a reason that will be presently
explained.
The dial and its connected apparatus are located at a central station at which
there are always one or more persons in attendance. The signal boxes are placed,
as usual, in different parts of a city or village, and each connected with one of the
magnets F and with the magnet E.
The circuit is an open metallic circuit running through gong and bell magnets in
engine houses and bell towers.
The operation of the parts is as follows:-On the ringing in of an alarm from
any box, say 24, the magnet F connected with that box is operated, and also the
magnet E, which is common to all the box circuits. This causes the stop d to be
removed from the path of the pointer B, and also causes the end of the extension k
to be pushed out into that path. The pointer B on being released travels in the
direction of the arrow until it strikes against the end of extension k which, in
obedience to the superior power of the spring b, moves to the opposite end of the
slota, thereby breaking the circuit of magnets F and E at n, k, and cutting out of
the circuit all magnets except the gong and bell magnets.
The circuit is now from one pole of the battery through the signal box 24 to the
binding post p, to extension k, to pointer B, to shaft C, and back to the battery
through the gong and bell magnets in the towers and engine houses. The first
stroke of 24 is made on the gongs. and bells when the circuit is first completed
through magnets F and E; the remaining strokes are made after those magnets
have been cut out,

page_text: The extension will be held in its forward position by the force of the spring h
pushing against the end of the pointer B. After the signal has been sent in; the
extension will be restored by hand, or by automatic mechanism, as desired.
It will be observed that both the original and the secondary circuits pass through
the pointer B. As soon, therefore, as the pointer B has left the stop d, there is no
circuit for any box except one that has already been operated. Moreover, in case
two boxes should be operated at the same time, the pointer B would be mechanically
obstructed from passing to the extension which was farthest around the dial,
until the nearest extension k had been pushed back after the receipt of its box
signal.
The magnets F and E being operated simultaneously, the end of extension / will
always be out in position to engage the pointer B as soon as it comes along.
The successive numerals in Fig. 2, indicate successive portions of the electric
circuits.
The box S will usually be made of wood. The dial is shown as forming part of
the front of the box. It may be formed separately and attached to the box by
suitable means.
It will be seen that the signal boxes T, are each connected in two directions with
one pole of the battery, a feature by virtue of which no box is cut out, unless the
circuit is broken on both sides thereof. If preferred, a loop may be run from each
binding post p, and connected to a separate box, whereby each box will have double
connections with each pole of the battery.
The system which has been described as a system of fire telegraphy might easily
be employed as a secret telephone system, in which every subscriber out of a
given series, except the one first calling, should be automatically shut out from
communicating through the central office.
Having now particularly described and ascertained the nature of the said
Invention, and in what manner the same is to be performed, I declare that what
I claim is
1. The combination with two electric circuit conductors, one running from one
pole of a generator back to the same pole and the other running out from the
opposite pole, of two or more circuit closers in multiple are relation between the
said conductors, and receiving apparatus at one or more stations for receiving
the signal when any one of the circuit closers is operated, substantially as set
forth.
2. The combination with two electric circuit conductors, one running from one
pole of a generator back to the same pole and the other running out from the.
opposite pole, of two or more circuit closers in multiple arc relation between the
said conductors, and apparatus at a central station actuated by the operation of
any circuit closer whereby every other circuit closer is cut out of the circuit,
substantially as set forth.
WP. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
and 323, High Holborn, London,
Patent Agents for the Applicant.