Improvements in Electric Fire-alarms, Applicable also for Use as Lightning Arresters.
Year: 1886

page_text: Date of Application, 8th Apr., 1886.
Complete Left, 10th Jan., 1887.
Complete Accepted, 11th Feb., 1887.
PROVISIONAL SPECIFICATION.
Improvements in Electric Fire-alarms, Applicable also for Use
as Lightning Arresters.
I, GEORGE ALANSON MASON, of 109 Farringdon Road, in the County of Middlesex,
Electrical Engineer, do hereby declare the nature of this Invention to be as follows:-
My Invention relates principally to apparatus of the kind wherein a fusible material
is employed to be acted upon by heat on the occurrence of a fire to give an alarm.
According to my Invention 1 employ a normally closed electric circuit which is kept
closed by means of a fusible material in such a position as to retain a spring in an
abnormal position. The circuit passes through a piece of tin foil or other conducting
material of a strength insufficient to resist the power of the spring when it is released.
On the occurrence of a fire the fusible material is fused and the spring is released and
it breaks the tin foil or the like, and, by thus breaking the circuit for the electric
current, causes an alarm to be given. The apparatus can also be used as a lightning
arrester.
J. HENRY JOHNSON.
47, Lincoln's Inn Fields, London, W.C.,
Agent for the said George Alanson Mason.

page_text: Improvements in Electric Fire Alarms, Applicable also for Use
as Lightning Arresters.
1 GEORGE ALANSON MASON of 109 Farringdon Road in the County of Middlesex
Electrical 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:-
My Invention relates to apparatus of the kind wherein a fusible material is employed
to be acted upon by heat on the occurrence of a fire to give an alarm or to break a
circuit to prevent lightening injuring electrical apparatus. According to my Invention
I employ a normally closed electric circuit which is kept closed by means of a fusible
material in such a position as to retain a spring (or its equivalent) in an abnormal
position. The circuit passes through a piece of tin foil or other conducting material of
a strength insufficient to resist the power of the spring or its equivalent when it is
released. On the occurrence of a fire the fusible material is fused and the spring is
released and it breaks the tin foil or the like, and by thus breaking the circuit for the
electric current causes an alarm to be given. Lightening in like manner will melt the
fusible material when the apparatus used as a lightening arrester for protecting
electrical machines The accompanying drawings represents a way in which my
Invention can be performed. Figure 1 shews the device as consisting of two
springs A A held in a tube B in an expanded condition the loop of each spring
having passed through it a bar & secured to the tube B. The inner ends of the
springs A A are connected by a tin foil strip C or any suitable conducting material
capable of being fractured by the force of contraction of the springs when released
from their expanded condition. The electric circuit is through the springs and the tin
foil. The springs are kept expanded by means of paraffin wax or other fusible material
filled into the space between the interior of the tube B and the springs.
Thus on the occurrence of undue heat in, or in the neighbourhood of the device the
fusible material melts and the springs contract and rupture the tin foil or the like
at and break the electric circuit to give an alarm in case of fire or to cut off the
electric circuit in the case of the device being used as a lightening arrester for
protecting electrical apparatus I do not limit myself to any particular way of making
the device shewn but a convenient way is to take a mould in longitudinal paris with
pins e in the one half which is shewn in Figure 2. The loops of the springs are put over
these pins, the springs being then in an expanded state and then the strip Čis soldered to
the springs and the mould being then closed the fusible material is cast into it. The
mould is then opened and the contents removed and placed in the tube B and the pins
passed through the ends of the said tube and through the end loops of the springs as
shewn. The circuit wires are then soldered or secured to the springs respectively.
It will be understood that I do not limit myself to the precise form of the device as

page_text: illustrated. For example the force tending to break the strip may be exerted
by but one spring A or it may be exerted by a blade spring or of a weight on a lever
as will be readily understood.
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:
First. In a normally closed Electric circuit, the use of a spring or weight tending
to break or rupture the circuit with a fusible material retaining the spring or its
equivalent in the position in which the circuit is closed substantially as hereinbefore
described.
Second. The combination for the purpose described of a spring or springs, kept in
an extended or abnormal position, by means of a fusible material, and having connected
to it or them a tin foil strip or equivalent piece which forms part of the circuit and is
ruptured by the contraction or movement of the spring or springs when the fusible
material is melted, substantially as described.
Third. The combination of parts constituting the Electric fire alarm or lightening
arrester as hereinbefore described and illustrated in the accompanying drawings.