Improvements in and connected with Electric Fire Alarms.
Year: 1894

page_text: Date of Application, 3rd May, 1894
Complete Specification Left, 4th July, 1894-Accepted, 4th Aug., 1894
PROVISIONAL SPECIFICATION.
Improvements in and connected with Electric Fire Alarms.
We ANDREW ARCHIBALD, of 6 Hanover Street, Edinburgh, in the County of
Midlothian, North Britain, Scientific Instrument Maker, and GEORGE TARRY, of
9 Bristo Place, Edinburgh aforesaid, also Scientific Instrument Maker, do hereby
declare the nature of this invention to be as follows:-
This invention relates to improvements in electric fire alarms, and has for its
object a new, and efficient method of holding and insulating the fusible metal plug.
The invention consists of a vulcanite or other insulated base on which is screwed
or otherwise fixed an upright standard. In the centre of this standard there is a
platinum point or button, and at the top thereof there is a vulcanite or other
insulated box or holder for containing the fusible metal plug or piece. This
standard is held in position by a terminal, which is also used to convey the current.
On the other side of base, also attached by a terminal, is a metallic spring with
platinum point or button pressing against opposite point or button which has a hole
for receiving one end of the fusible plug, the other end of the plug being pressed
into the box or holder on opposite side. The points are thus kept apart until fire
occurs, when the fusible plug melts and the current is completed.
The whole instrument is enclosed in a suitable case.
Dated this 2nd day of May 1894.
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicants' Agents.
COMPLETE SPECIFICATION.
Improvements in and connected with Electric Fire Alarms.
We, ANDREW ARCHIBALD, of 6 Hanover Street, Edinburgh, in the County of
Midlothian, North Britain, Scientific Instrument Maker, and GEORGE TARRY, of
9 Bristo Place, Edinburgh aforesaid, also Scientific Instrument Maker, 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 improvements in electric fire alarms, and has for its
object a new and efficient method of holding and insulating the fusible metal plug.
In order that our invention may be properly understood and readily carried into
effect we have hereunto appended an explanatory sheet of drawing which we will
now proceed to describe.
Figure 1 is a front elevation of one form of our improved electric fire alarm, and
Figure 2 is a similar view of an alternative method.
The invention consists of a vulcanite or other insulated base, A on which is
screwed or otherwise fixed an upright standard B. In the centre of this standard
there is a platinum point, button, or contact making piece C, and at the top thereof
there is a vulcanite or other insulated box or holder D for containing the fusible
metal plug or piece E. This standard B is held in position by a terminal F on one
side of the base A, which is also used to convey the current. On the opposite side
of base A, also attached by a terminal G is a metallic spring H with platinum
point, button, or contact making piece C¹ pressing against opposite point, button,
or contact making piece C on the standard as described. The top end of the said
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page_text: metallic spring H has a hole for receiving one end of the fusible plug E, the other
end of the plug being pressed into the box or holder D on opposite side. The
points are thus kept apart until fire occars, when the fusible plug E melts and
the current is completed by the points C C¹ coming together, thus allowing the
apparatus to sound an alarm.
Figure 2 represents a much simpler form of electric fire alarm. The standard
and clamping screws of both terminals are dispensed with, and the ends or terminals
of both conductors are connected to the screws I and J ; the screw I securing the
one end of the flat spring H¹. In or about the middle of this spring is fixed a
platinum point or button Cl. A similar platinum point or button C is inserted into
the head of the screw J. The free end of the spring His lifted from the base A,
and the platinum contact pieces C and C¹ are kept apart by means of the fusible
plug E, which in the case of fire becomes melted by the heat, and the circuit of
the two terminals is completed, and so allows the apparatus to sound an alarm as
.described.
The whole instrument is enclosed in a suitable case.
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 :-
.
In electric fire alarms the method of holding and insulating the fusible metal
plug substantially as hereinbefore described and shown on the accompanying sheet
.of drawing.
Dated this 3rd day of July 1894.
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicants' Agents.