Improvements in Fire-alarms.
Year: 1896

page_text: Date of Application, 19th May, 1896
Complete Specification Left, 27th Nov., 1896-Accepted, 27th Mar., 1897
Improvements in Fire-alarms.
We, JOHANNES CAROC, NIELS SMITH, and EMIL SCHIEMANN, all of
68, Nörrebrogade, Copenhagen, in the Kingdom of Denmark, Works Directors,
do hereby declare the nature of this invention to be as follows:-
This invention relates to an apparatus for signalling fire-alarms to a central
station in which "false alarms" are prevented or rendered less likely of occurrence
than heretofore. To this end the person giving the signal is caused to turn a
handle which sounds a loud toned gong or bell arranged on the apparatus, whilst
the signal is only sent to the fire station, by the closing of an electric circuit,
shortly after the person signalling has ceased turning the handle and thereby
Bounding the gong or bell.
The handle or crank simultaneously actuates the sounding apparatus by means
of two bevel wheels and a disc, which is provided with a projecting pin, by means
of a worm.
By means of suitable gearing and levers a clockwork device is released, the
said clockwork device being actuated by a weight suspended on a chain which is
wound on a disc or wheel. This disc or wheel can, when the clockwork device is
released, move through half.a revolution and during this rotation it carries with
it, by means of a pawl, a toothed wheel which is arranged loose on its shaft, two
other shafts of the clockwork being also actuated through the medium of suitable
gearing. Of these two spindles or shafts one actuates the signal at the fire
station and the other carries a fly for regulating the speed of the clockwork.
The chain disc or wheel, which is keyed to a spindle, is connected with a ratchet
disc provided with two notches or teeth. The object of this ratchet disc is to
serve as a support for one end of each of two three armed pawls, whilst the
signalling is being effected after the pawls have been removed from their position
by the pin on the first named disc whereby they release the clockwork, for the
purpose of preventing the said pawls from falling back into their original position
and from engaging with the ratchet disc of the clockwork on the shaft before the
ratchet and chain discs have made a half revolution.
By
A hammer-shaped hand lever, which is rigidly connected with the chain disc
through the medium of its shaft, is also caused to make a half revolution.
opening the case of the apparatus and pulling the hand lever upwards through half
a revolution the clockwork is again wound up and made ready to deliver another
signal. The hammer-shaped head of the hand lever also serves another purpose
as it is provided with a suitable inscription whereby, when the apparatus is in
proper order for delivering a signal, the inscription to this effect is visible beneath
a small glass window in the side of the case of the apparatus.
It is only possible to turn the handle and to forward a signal when the apparatus
is wound up and the hand lever therefore is in its upper position as the head of
the said hand lever holds a pawl from the teeth of a toothed wheel on the crank
or handle axle only when in this position, the said pawl being otherwise forced
against the teeth so as to stop the rotation of the axle or shaft.
As this pawl acts as soon as the clockwork is set in motion, one of the three
armed pawls would not be sufficient of itself to stop the clockwork when the

page_text: signal has been made as it is held back by the pin on the disc. The other three
armed pawl is therefore so placed that the pin on the disc first lifts it out of its
position and brings one end on to a projection on a movable lever whereby it
remains out of engagement until the other pawl is released, the clockwork is in
motion, and one of the pins on the ratchet disc by pushing the movable lever aside
has set free its end.
·
1000
Improvements in Fire-alarms.
We, JOHANNES CAROC, NIELS SMITH, and EMIL SCHIEMANN, all of
68, Nörrebrogade, Copenhagen, in the Kingdom of Denmark, Works Directors,
do hereby declare the nature of this invention and in what manner the same
is to be performed to be particularly described and ascertained in and by the
following statement :-
This invention relates to an apparatus for signalling fire-alarms to a central
station in which "false alarms" are prevented or rendered less likely of occurrence
than heretofore. To this end the person giving the signal turns a handle which
sounds a loud toned gong or bell arranged on the apparatus, whilst the signal is
only sent to the fire station, by the closing of an electric circuit, shortly after the
person signalling has ceased turning the handle and thereby sounding the gong or
bell.
To enable our invention to be fully understood we will describe it by reference
to the accompanying drawing, in which :-
Figure 1 is a side view of a fire-alarm constructed according to our invention.
Figure 2 is a view to a larger scale shewing the mechanism.
The handle or crank a simultaneously actuates the sounding apparatus 6 by
means of two bevel wheels and a disc c, which is provided with a projecting pin,
by means of a worm.
By means of suitable gearing and levers a clockwork device is released, the
said clockwork device being actuated by a weight V suspended on a chain which
is wound on a disc or wheel d. This disc or wheel can, when the clockwork
device is released, move through half a revolution and during this rotation it carries
with it, by means of a pawl e a toothed wheelf which is arranged loose on its shaft,
two other shafts j and k of the clockwork being also actuated through the medium
of suitable gearing g, h, i. Of these two spindles or shafts one j operates the
signal at the fire station and the other k carries a fly for regulating the speed of
the clockwork.
The chain dise or wheel d, which is keyed to the spindle m is connected with a
ratchet disc n provided with two notches or teeth. The object of this ratchet
dise n is to serve as a support for one end of each of two three-armed pawls p
and 9, whilst the signalling is being effected after the pawls have been removed
from their normal position by the pin on the disc c whereby they release the clock-
work, for the purpose of preventing the said pawls from falling back into their
original position and from engaging with the ratchet dise of the clockwork on the
shaft before the discs d and n have made a half revolution.
A hammer-shaped hand lever o, which is rigidly connected with the disc d
through the medium of its shaft m, is also caused to make a half revolution. By
opening the case of the apparatus and pulling the hand lever o upwards through

page_text: half a revolution the clockwork is again wound up and made ready to deliver
another signal. The hammer-shaped head of the hand lever o als serves another
purpose as it is provided with a suitable inscription whereby, when the apparatus
is in proper order for delivering a signal, the inscription to this effect is visible
through a small glass window in the side of the case of the apparatus.
It is only possible to turn the handle and to forward a signal when the apparatus
is wound up and the hand lever therefore is in its upper position as the head of the
said band lever bolds a pawl from the teeth of a toothed wheels on the crank or
handle axle only when in this position, the said pawl being otherwise forced against
the teeth so as to stop the rotation of the axle or shaft.
As this pawl acts as soon as the clockwork is set in motion, the three-armed
pawl g would not be sufficient of itself to stop the clockwork when the signal has
been made as it is held back by the pin on the disc c. The other three-armed
pawl p is therefore so placed that the pin on the disc e first lifts it out of its
position and brings one end on to a projection on a movable lever whereby it
remains out of engagement until the other pawl y is released, the clockwork is in
motion, and one of the pins on the ratchet disc n by pushing the movable lever t
aside has set free its end.
The shaft is provided with any suitable known device in connection with an
electric current having a bell at the fire station whereby when the said shaft is
rotated the device alternately makes and breaks the electrical connection so as to
ring the bell.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. In fire-alarms the combination of a crank shaft provided with a crank or handle
arranged outside the case of the apparatus with a sound producing device such as
a gong or bell and with clockwork which after the sounding device has been
operated for some time by the rotation of the crank, is released by the rotation of
the crank shaft through the medium of a lever connection so that the alarm is
automatically forwarded to the station after the rotation of the crank or handle
and the sounding of the gong, bell or other device have ceased, substantially as
hereinbefore described.
2. In fire-alarms the combination of an accessible crank or handle which can be
rotated when the apparatus is in its normal position but which cannot transmit a
signal without previously sounding a gong, bell or other suitable device on the fire-
alarm, with a disc provided with a pin which dise in consequence of the rotation of.
the crank or handle releases, after a certain interval, a ratchet disc in connection
with clockwork by means of a ratchet and lever arrangement, with a ratchet disc
provided with one or more notches which disc whilst it rotates through half a
revolution allows the clockwork to operate and the signal to be transmitted and
with a hammer-shaped hand lever connected to, the above described disc which
hand lever when pushed back to its normal position winds up the clockwork and
simultaneously indicates that the apparatus is ready to be again used all
substantially as hereinbefore described and illustrated.
3. In fire-alarms the combination of a crank or handle arranged on the outside of
the apparatus with enclosed clockwork mechanism and with a hammer-shaped
hand lever in connection with a chain disc carrying the operative weight, which
hand lever indicates by its position whether the apparatus is ready or not for use,
the said parts being so arranged and connected with one another that the clock-
work is not released until the crank has been rotated for a certain length of time
the said clockwork being released simultaneously with the locking of the crank or
handle by a pawl arrangement and the said crank being locked until the hammer-
shaped hand lever is pushed back so as to again wind up the clockwork and bring
the parts of the apparatus into their normal position, substantially as, hereinbefore
described and illustrated.

page_text: 4. The combination and arrangement of parts forming the improved fire-alarm
hereinbefore described and illustrated in the accompanying drawings.
Dated the 23rd day of November 1896.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.