AN IMPROVED AUTOMATIC FIRE ALARM AND HEAT INDICATOR to be as follows:
Year: 1885

page_text: I ALFRED HUDSON of 34 Hatton Garden, London, in the County of Middlesex
Mathematical Instrument Maker do hereby declare the nature of my invention
for "AN IMPROVED AUTOMATIC FIRE ALARM AND HEAT INDICATOR to be as
follows:-
"
M
This invention relates to improvements in automatic fire alarms and is designed
to supply a reliable self acting fire alarm of a novel but simple construction which
shall be certain in action and unlikely to get out of order.
Hitherto fire alarms of this description have been made to actuate a bell or other
alarm by means of the thermometer the rise of the mercury serving to make the
contact of two pieces of metal and thus close an electric circuit, and start a bell or
bells ringing--now in place thereof I use animal membrane such as cat gut or other
similar substance which although only slightly sensible to the ordinary variations
of air temperature is greatly agitated and higly sensitive in a flame or current of
hot air either dry or moist (such as steam) when at a temperature of 50 Centigrade
or thereabouts.
This tissue or membrane is enclosed in a tube advantageously made of copper
open at each end-at one end an enlarged mouth may be placed to collect heat or
flame while at the other is placed a mechanical arrangement (enclosed in a box made
of ebonite or other suitable non-conducting material) by which when the tem-
perature rises above a given limit the agitation and contraction of the cat gut or
other suitable material is communicated to a metal bar or arm which is so attached
to be brought into contact with the two poles of an electric circuit which it closes
and thereby causes a bell or bells to sound and thus raise an alarm.
.In the construction of these improved alarms any suitable materials may be used
and the dimensions of the apparatus may vary according to the purposes to which
they are to be applied.

page_text: An Improved Automatic Fire Alarm and Heat Indicator.
I ALFRED HUDSON of 34 Hatton Garden London in the County of Middlesex
Mathematical 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 automatic fire alarms and is designed
to supply a reliable self acting fire alarm of a novel but simple construction which
shall be certain in action and unlikely to get out of order.
Hitherto fire alarms of this description have been made to actuate a bell or other
alarm by means of the expansion of air acting upon a diaphragm and also by a
thermometer the rise of the mercury serving to make the contact of two pieces of
metal and thus close an electric circuit and start a bell or bells ringing—now in
place thereof I use animal membrane or tissue in strips or lengths such as catgut
or other similar substances which although only slightly sensible to the ordinary
variations of air temperature is greatly agitated and highly sensitive in a flame or
current of hot air either dry or moist (such as steam) when at a temperature of
50 Centigrade or thereabouts.
The tissue or membrane is enclosed in a tube advantageously made of copper
and conical. At one end an enlarged mouth may be placed to collect heat or flame
while at the other end is placed a mechanical arrangement (enclosed in a box made
of ebonite or other suitable non conducting material) by which when the temperature
rises above a given limit the agitation and contraction of the catgut or other suitable
material is communicated to a metal bar or arm which is so attached as to be brought
into contact with the two poles of an electric circuit which it closes and thereby
causes a bell or bells to sound and thus raise an alarm.
In the construction of these improved alarms any suitable material may be used
and the dimensions of the apparatus may vary according to the purpose to which
they are to be applied.
I would remark that the arrangement and construction of the apparatus employed
in carrying my invention into practice may vary considerably so long as it admits
of the contraction of a piece of catgut or strip of animal membrane being caused
to bring the two poles of an electric circuit into contact to give an alarm in case
of undue heat. I shall therefore proceed to describe an arrangement of apparatus
which I have found to be most effective for the above purpose.
And in order that my invention may be clearly understood and readily carried
into practice I will proceed to describe the drawing hereto annexed.
DESCRIPTION OF THE DRAWING.
Figure 1 shows a vertical section of my improved automatic fire alarm apparatus
and heat indicator and Figure 2 is a transverse section through the line 1. 1.
a is a length or strip of cat gut or other animal membrane connected at one end
to a disc a' which can be raised and lowered by the travelling nut and screw b³ in
order to adjust the position of the ball (or it may be a bar) a³ (mounted on the
other end of the cat gut) at a suitable distance from the end of the two wires or

page_text: poles c. c. of an electric circuit the contraction of the cat gut when over heated
acting to draw the ball a' into contact with the platinum terminals of the wires or
poles c. c. to close the electric circuit and thus cause an alarm bell to ring or to
indicate undue temperature.
The conducting wires c. c. are connected to the cap 61 (lined with wood or other
non-conducting material) on the end of the conical tube b the lower end of the tube
being enlarged to receive the heated air.
The disc a¹ is prevented from revolving by a projection a³ fixed thereon which
passes through a slotted guide a fixed on the cross bar bs carried by the internal
sliding tube 6 through which the screw 6' passes and the disc a¹ is pressed down
upon the travelling nut 62 by a spiral spring acting against a collar on the end of
the screw b³.
The apparatus may be suspended by the loop 6' or it may be placed in a hori-
zontal or other position in which case a slight spiral spring is arranged above the
ball a to retain it in position.
The contraction of the cat gut or membrane may be so arranged as to release
a catch or withdraw a bolt and thus set suitable clock work or other mechanism
in motion to give an alarm or indicate undue heat in accordance with my
invention.
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 application and adaptation of cat gut or strips of animal membrane to a
fire alarm or heat indicator whereby an alarm is given either mechanically or
electrically when contraction of the tissue is caused by undue heat substantially as
described.
2. The improved automatic fire alarm and heat indicator arranged to act sub-
stantially as described and represented in the drawings hereto annexed.
TONGUE & BIRKBECK,
Agents for the Patentee.