Improvements in or connected with Fire or Temperature Alarms.
Year: 1899

page_text: Date of Application, 8th Dec., 1899-Accepted, 8th Dec.,
1900
0
COMPLETE SPECIFICATION.
Improvements in or connected with Fire or Temperature Alarms.
I, LEON DAVOINE, of 31, Lloyd's Row, Clerkenwell, in the County of London,
Engineer, 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 thereof reference being had to the drawings hereunto
annexed and to the figures and letters marked thereon, that is to say:-
The invention relates to improvements in or connected with fire or temperature
alarms.
Many attempts have been made to devise a fire alarm of such a simple character
as to warrant its coming into general use but at the present time it would be
difficult to find, at any rate in private houses, an efficient fire-alarm in proper
working order and as a consequence fires having fatal results are of common
occurence.
One reason for the non-employment of fire-alarms in private houses is that
such devices are generally of an expensive and complex nature requiring special
installations and frequent after attention otherwise they are liable to become
inoperative.
Now the primary object of the present invention is by a simple and inexpensive
device requiring no attention to utilize the ordinary electric bell or like installa-
tions which are now fitted in almost every house and in constant use and there-
fore always in good working order and to convert the same into automatic fire
alarms but a further object of the invention is to give warning of an undue rise
of temperature in situations such for example as wine or beer cellars or vats or
the holds of vessels where such a rise would be prejudical to the goods.
In the accompanying drawings in which like parts are indicated by similar
letters of reference.
Figure 1 is a vertical section of an ordinary rose shaped push or switch of an
electric bell installation having the present invention applied thereto and showing
the parts in their set position.
Figure 2 is an elevation showing the cap detached from the base.
Figure 3 is a plan of the base separately.
Figure 4 is a vertical section of the stud separately.
Figure 5 is a vertical section of parts showing the device in action.
Figure 6 is a diagrammatic view illustrating the application of the invention
to a telephone or like installation and
Figure 7 is a side elevation illustrating the application of the invention to an
independent alarm apparatus.
In the several figures in which like parts are indicated by similar letters of
reference. Figures 4 and 5 are drawn to an increased scale with respect to the
other figures of the drawings.
Referring to Figures 1 to 5 a is the base of the rose which is adapted to be
fastened to a wall or other surface in the manner well known, a¹ is a threaded
cylindrical projection from the base a and a² is a cap which screws thereon.
The projection a¹ carries the usual contact making devices one b consisting

page_text: of a flat plate of German silver or the like connected by a conductor 6* with one
pole of an electric battery and the other consisting of a semi-circular spring c of
similar material connected by a conductor c* with the other pole of the battery,
the opposed faces of these devices being preferably formed of platinum to afford
an efficient contact and the spring contact c is adapted to be pressed onto that bin
order to complete the circuit and sound the alarni by means of a stud or button d
which works in an axial perforation in the cap a² as is usual.
According to the present invention however the stud or button d instead of
being solid as heretofore is formed 'hollow as a box or capsule and
the outer end of this box d is immovable with relation
thereto and
whilst the inner end is
permanently closed
closed by a movable
cap provided with a tubular flange &³ formed to hermetically fit and telescopi-
cally slide within the box d and the corresponding end of the box is
formed with a projecting annular seat or shoulder within which is received
the cap and this shoulder also serves the purpose of the usual flange which
prevents the stud or button d passing bodily through the perforation of the cap a².
Within the hollow stud or button d is arranged a coiled spring d which at
one end takes an abutment against the outer end of the box and at the other
end terminates in a spindle or stud da provided with an enlarged end which
bears against the inner face of the cap and in the absence of some controlling
means serves to project the same and depress the contact c upon that b.
In order however to store the power of the spring and hold the same out of
action until the pre-determined conditions under which the device is to operate
have been realised a quantity of any suitable readily fusible metal or composi-
tion e is introduced into the cap previous to the putting together of the parts and
said material is by the aid of heat rendered fluid or plastic, the spring is then
inserted in the stud d and the cap is then placed in position and by means
thereof the spring is compressed; the fusible material is then caused to set or
solidify by immersing the now complete stud d in water or otherwise when the
spring will be held in its compressed or stored position until the fusible
material is again softened by an undue increase of temperature.
Upon the temperature rising to a point at which the fusible material e is
rendered fluid or plastic, said material becoming softened will relax its hold
of the spring and the stored power of the latter will assert itself and project
the cap pressing the contact c upon that thereby completing the electric
circuit and causing the bell or other alarm to be continuously sounded.
In order to restore the parts to their normal or set positions it is merely neces-
sary to unscrew the cap a², detach the stud d heat the same sufficiently to render
the fusible composition fluid or plastic and press the cap d² into its retracted posi-
tion thereby compressing the spring and thus hold it until the fusible material
has solidified which may be hastened by immersing it in cold water when the
power of the spring d will be again stored and the stud d may. be reinserted in
the cap a in the usual way.
With a view to render the apparatus more sensitive to undue heat created on
the opposite side of a wall to which the push is affixed a recess is provided
in the base a and projection a¹ and this recess is filled to a suitable extent with
the readily fusible material e whilst the contact plate is sprung towards the
contact c but is provided with a downwardly extended waved tongue 6 which is
embedded in the fusible composition e.
Upon the fusible material e becoming softened the spring, contact 6 is released
and, rising, makes contact with that c with the result that the alarm is sounded
and in order to restore the spring contact to its normal position the fusible
material is rendered plastic by the aid of any suitable heating means and the
spring contact b is depressed and thus held until said material has become
sufficiently set.
The readily fusible material employed may be of any suitable kind which will
become sufficiently plastic or fluid at the temperature at which the apparatus is
required to act but it has been found by experiment that a composition of bees-

page_text: wax and resin in equal proportions will become sufficiently softened or plastic at
a temperature of about 130 degrees Fahrenheit to release the spring or the
tongue and this condition may be easily modified within certain limits by
varying the proportions of the ingredients an increase of resin raising the melting
point and vice versa.
It will however be obvious that various other readily fusible materials are
equally applicable to the present invention but those from which mercury is
absent are preferable as the latter material would be calculated to oxidize the
contacts and thus injuriously affect the efficient working of the apparatus.
The studs d may be readily applied to all existing pushes without alteration
thereof and for convenience they are marked with numbers indicative of the par-
ticular degree of temperature at which the device is calculated to become operative
and the material of which they are made may for example be thin aluminium
German silver or the like for moderate temperatures or wood, vulcanite porcelain
or the like for higher temperatures.
In the example given at Figure 6 a method of applying the invention to a
telephone or like installation is illustrated.
In this case the contact bis placed in electrical connection with one of the
conductors 6* and the contact c with the other c* of said conductors as in the
previous arrangement and these parts and the stud or box d are held in a kind of
frame a the stud or box d being mounted in a removable holder a so as to
be capable of easy removal for the purpose of renewal or otherwise.
It will be obvious that the details of the invention may be otherwise varied
according to the situation and conditions in which it is to be employed and
that by suitably proportioning the constituent parts of the fusible material the
device may be employed as a temperature alarm in places such for example as
beer or wine cellars or the holds of vessels where an increase of temperature would
injuriously affect the contents thereof, whether actually giving rise to fire or not.
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
1. An alarm apparatus comprising a body of readily fusible material, a spring
retained in a compressed or stored position by said material and means adapted
to be moved by said spring and brought into action to sound an alarm upon
the softening of the fusible material substantially as herein shown and described.
2. An alarm apparatus comprising a box, a body of readily fusible material
within the box, a spring located within the box and adapted to be retained in its
compressed position by said material and a moveable part carried by the box
adapted to be acted upon by the spring to bring into action an electric or other
alarm apparatus upon the softening of the fusible material substantially as herein
shown and described.
3. An alarm apparatus comprising an electric bell push or contact maker fitted
with a push stud or button consisting of a box, a body of readily fusible material
within the box, a spring located within the box and adapted to be retained in its
compressed position by means of said material and a moveable part carried by
the box adapted to be acted upon by the spring to bring together the ordinary
electric contacts of the push upon the softening of the fusible material substan-
tially as herein shown and described.
4. An alarm apparatus comprising an electric bell push or contact maker fitted
O with a push stud or button consisting of a box, a body of readily fusible material
within the box, a spring located within the box and adapted to be retained in its
compressed position by means of said material, a moveable part carried by the
bring together
box adapted to be acted upon by the spring to
the electric contacts of the push upon the softening of the fusible
5 material, a cavity in the base of the push, a body of fusible material
in said cavity a spring contact plate carried by the base and a waved tongue

page_text: or the like from said contact plate extending into the fusible material in the
cavity so that said spring will normally be held in compression but upon the
softening of said material said contact will be thrown into engagement with the
other contact plate substantially as herein shown and described.
5. An alarm apparatus constructed arranged and operating substantially as
herein shown and described.
WHITE & WOODINGTON,
Birkbeck Bank Chambers, Southampton Buildings, London, Agents.