IMPROVEMENTS IN ELECTRIC STREET FIRE ALARMS
Year: 1884

page_text: I, JOHN ROBERTS of 33 Loscoe Road, Carrington, Nottingham, Nottinghamshire,
Electrician, do hereby declare the nature of my said invention for "IMPROVEMENTS
IN ELECTRIC STREET FIRE ALARMS," to be as follows:-
:-
This Invention relates to electrical apparatus, to be fixed in various quarters or
parts of a town, or buildings and used for giving an alarm to a central station on
the outbreak of a fire in any of such parts, and it is the principal object of the
Invention to obviate the liability to give false alarms which exists in the apparatus
commonly used.
In carrying out the Invention the improved apparatus is enclosed in a suitable
casing having a glass panel in its front and a small piece of glass arranged to be
broken when giving an alarm. Inside facing the small piece of glass there is a
small button or pusher which is maintained in a normal position and out of electric
contact by a spring. On giving an alarm this button is pressed inwards and a
part connected to it by this action forces inward one end of a lover which is so
centered that its other end having suitable parts for making electrical contact is
moved outwards. This lever has formed upon it a small boss or enlargement
through a hole in which the outer end of an arbor of a toothed wheel passes.
This wheel is connected to a suitable train of wheels actuated by a coiled spring
and on the outer end of its arbor which passes through the contact making lever,
there is a small stud or pin. This stud or pin is arranged to fit into a groove or
recess formed in the boss or enlargement on the lever when that end of the lever is
pressed outwards by the action of a spring. This arrangement locks the arbor and
its wheel and stops the movement of the train of wheels so long as it remains in
that position. On an alarm being given by pressing the button, the lever end is
pressed away and released from the arbor pin or stud and caught by a small bell
crank lever catch piece. The arbor thus released allows the train of wheels to
turn by the action of the coiled spring which has been previously wound up. On
one side of one of the wheels of the train there is arranged a series of pins or studs
say three sets of five pins-and a spring contact making piece is arranged to
vibrate by the action of these pins or studs as they are brought round by the
revolution of the wheel. This vibrating contact piece is connected to the bell in
the casing and causes it to ring the same number of times as there are pins on the
wheel. At the same time the bell at the principal station connected with the

page_text: apparatus will be rung in the same manner. The bells will continue to ring until
either the spring actuating the train of wheels has run down or the lever is released
from the catch piece and its boss engages with the pin on the end of the arbor.
The release of the lever from the catch piece will be effected on inserting the key
to rewind the spring, the key coming into contact with a part of the catch lever
pressing the lever down and thus releasing the lever. The current is led into the
apparatus through the coils of the electro magnets of the bell thence to the metal
of the train of wheels and through the vibrating contact making piece on its touching
any of the pins or studs on the wheel of the train to earth, when contact is made
with the earth wire by means of a spring piece connected to that wire. This spring
piece is brought into contact with the vibrating piece when the end of the lever
acted on by the button is pressed inwards and caught by the spring catch.
By the foregoing improved arrangement or combination of apparatus the present
liability of street fire alarms to cause false alarms is entirely obviated as should the
connecting wires at any part between the apparatus and central station be put into
electrical contact the bell will not ring intermittently but continuously thus at once
showing a false or accidental alarm has been given,

page_text: I, JOHN ROBERTS of 33 Loscoe Road, Carrington, Nottingham, Nottinghamshire,
Electrician, do hereby declare the nature of my said Invention for "IMPROVEMENTS
IN ELECTRIC STREET FIRE ALARMS," and in what manner the same is to be
performed to be particularly described in and by the following statement that is
to say :-
My said Invention relates to electrical apparatus to be fixed in various quarters
or parts of a town or buildings and used for giving an alarm to a central station on
the outbreak of a fire in any of such parts and it is the principal object of the
Invention to obviate the liability to give false alarms which exists with the
apparatus commonly used.
In carrying out my said Invention the improved apparatus is enclosed in a
suitable casing which may have a glass panel in its front and a small piece of
glass arranged to be broken when giving an alarm. Inside facing the small piece
of glass there is a small button or pusher which is kept out of electric contact by
a spring. This pusher is arranged when it is pushed inwards in giving an alarm
to release a train of wheels moved by a coiled spring, one of which wheels has
fixed upon it a number of short pins or projections arranged in a series of five or
other suitable number. An electrical contact maker is arranged to touch these
pins as the wheel revolves and so make intermittent contact and cause the electric
bell at the station to ring intermittently according to the arrangement of the series
of pins instead of ringing continuously as at present. The ringing of the bell
continues until the clock work runs down or until the key is inserted to rewind up
the clockwork, when the key comes in contact with a spring catch and lever arrange-
ment which locks the train of wheels until the pusher is again pressed inwards.
And in order that my said Invention and the manner of performing the same
may be properly understood I hereunto append a sheet of explanatory drawings to
be hereinafter referred to and representing my improvements.
In these drawings
the same reference numerals are used to mark the same or like parts wherever they
are repeated.
Figure 1 on the accompanying sheet of drawings is a full size side elevation
showing my improved arrangement of apparatus as arranged to be used for a
street fire alarm and Figure 2 is a back view of the apparatus with a part of the
framing or casing removed. Figure 3 is a front view of a part of the apparatus
showing a detail full size and will be hereinafter referred to. The improved
apparatus is principally contained within a rectangular box or casing, 1, preferably
formed of cast iron the apparatus being arranged upon a plate, 2, so that when this
plate is screwed upon the open side of the box, 1, the principal parts of the
mechanism are contained within the box, 1. In the middle of this plate, 2, there
is fitted a pusher, 3, pressed outwards by a blade spring and the inner end of this
pusher 3 bears against the upper end of a vertical lever piece, 4, which is centered
by its lower end upon a stud, 5, on a small plate, 6, screwed upon a metal plate, 7,

page_text: near the bottom. Between this plate, 7, and another one, 8, parallel to it there is
arranged a train of three wheels actuated by a coiled spring and regulated by an
escapement lever similar to clockwork. These plates 7, 8, are bolted together and
the plate, 7, is secured to the plate, 2, a short distance apart with the lever piece
between. The upper end of this lever, 4, has a circular enlargement in it just below
the point where the pusher, 3, bears against it. Through a hole in this enlarge-
ment there projects the arbor, 9, of one of the wheels of the train aforementioned,
and this arbor, 9, has a pin fixed crosswise through its end, which when the
pusher, 3, is in its normal position as in Figure 1 comes into contact with two
studs or pins, 10, (best seen in Figure 3) and prevents the rotation of the arbor, 9,
and its wheel and thus locks the clock work. The lever, 4, is kept in this position
by a blade spring, 11, but on an alarm being given and the pusher pressed inwards
the lever, 4, is pushed inwards against the spring, 11, and the cross pin removed
from the pins, 10 whilst at the same time a small projection or catch, 10, on the
front of the lever 4, slips under a catch on a small bell crank lever, 13, which is
centered at its angle on the plate, 7, being pressed upwards by a small spring, 14,
acting on its vertical leg. By this arrangement the arbor, 9, and its wheel is
released and the train of wheels is permitted to move by the action of the main-
spring, 15, which is fixed upon an arbor, 16, near the bottom. This arbor, 16,
projects beyond the plate, 7, and through an opening in the lever, 4, and extends
to near the plate, 2, and has its end squared to receive a key for winding the
spring. A circular hole is provided in the plate, 2, just below the pusher, 3, for
the insertion of the key, which key on being inserted and placed upon the arbor, 9,
comes, into contact with the downwardly extending leg of the bell crank lever, 13,
and by forcing this leg back it removes the catch from the lever catch and permits
the lever 4 to move forwards. The forward movement of the lever, 4, brings its
cross pin into contact with the pins, 10, and quickly stops the train of wheels.
When however the train of wheels is set in motion by pushing in the pusher, 3, as
herein before stated one end of a vibrating spring electric contact making piece, 17,
comes into contact with sets of pins fixed upon the side of one, 18, of the wheels as
it turns. These pins are arranged in two sets of four pins each (or it may be any
other suitable number) on the side of the wheel, 18, which is fixed on the arbor, 9,
and the end of the spring contact maker, 17, touches successively each of these pins
thus alternately making and breaking contact. The contact maker, 17, is secured
by one end on an insulated block, 19, fixed to the plate, 8, near the bottom and is
connected by a wire with the coils of the electro magnets connected with the
bells 20, 21, of which there are two fitted outside at the top of the plate, 2, above
the pusher, 3, and arranged to be struck alternately in a well known manner. The
current of electricity is led into the apparatus through the coils of the electro
magnets which are connected by a wire with the contact maker, 17. The circuit is
thus completed on the contact inaker, 17, touching one of the pins on the wheel, 18,
the current passing through the metal of the apparatus to earth. In order to give
a return signal to the apparatus from the station and ring the magnetic bells 20, 21,
a commutator is arranged at the station to reverse the current, the electro
magnets for ringing the bells in the apparatus being arranged similarly to those
in a telephone.
By the foregoing improved arrangements or combination of apparatus the present
liability of electric street fire alarms to cause false alarms is entirely obviated as
should the connecting wires at any part between the apparatus and central station
be put into electrical contact the bell will not ring intermittently but continuously
thus at once showing that a false or accidental alarm has been given.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is
(1.) The ringing of electric call bells at a station intermittently, substantially as
and for the purposes hereinbefore described,

page_text: (2.) The combination and arrangement of apparatus for intermittently ringing
electric fire alarm bells substantially as herein before described with reference to
the accompanying drawings.
(3.) The arrangement of a pusher, 3, in combination with a lever, 4, catch, 13,
and arbors 9, 16, of a train of wheels all operating substantially as and for the
purposes herein before described with reference to the accompanying drawings.
(4.) The arranging of magnetic bells in a fire alarm apparatus for giving
return signals from the station substantially as herein before described.
يمم