IMPROVEMENTS IN IN- STRUMENTS FOR ASCERTAINING AND INDICATING HEAT, AND ALSO IN THE PARTS FOR MAKING AND BREAKING CONTACT IN ELECTRIC CIRCUITS USED THEREWITH
Year: 1856

page_text: LETTERS PATENT to Alexander Symons, of George Street, Mansion House,
in the City of London, and Edward Burgess, of Clerkenwell Green, in
the County of Middlesex, for the Invention of "IMPROVEMENTS IN IN-
STRUMENTS FOR ASCERTAINING AND INDICATING HEAT, AND ALSO IN THE PARTS
FOR MAKING AND BREAKING CONTACT IN ELECTRIC CIRCUITS USED THEREWITH."
Sealed the 7th October1856, and dated the 22nd April 1856.
PROVISIONAL SPECIFICATION left by the said Alexander Symonds and
Edward Burgess at the Office of the Commissioners of Patents, with
their Petition, on the 22nd April 1856.
1, ALEXANDER SYMONS, of George Street, Mansion House, in the City of
London, and I, EDWARD BURGESS, of Clerkenwell Green, in the County of
Middlesex, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN INSTRUMENTS FOR ASCERTAINING AND INDICATING HEAT, AND ALSO IN THE
PARTS FOR MAKING & BREAKING CONTACT IN ELECTRIC CIRCUITS USED THEREWITH,
to be as follows:--
Our Invention of improvements in instruments for ascertaining and indi-
cating heat relates, first, to the combination of particular metalstobeemployed
as the part or parts sensitive to heat of such instruments, and whereby motion
is communicated to apparatus connected with a suitable scale or dial to afford
visible indication of the gradations of temperature, or to actuate apparatus
whereby an audible signal or alarum will be created. This iustrument is also
applicable for making & breaking the contact of electric circuits used for
this purpose.

page_text: Another improveined instrument for indicating heat consistsinplacing two
wires, coated with gutta percha or other suitable material, either twisted
together orotherwise, and establishing permanent pressure at different parts,
which, when the gutta percha becomes soft from the heat, the wires will effect
metallic contact, and complete the circuit of an electric current, and thereby
actuate an alarum or indicator; or the pressing points may be sharp and form
one part of the circuit, so that when the gutta percha becomes soft from heat,
the contact point will be forced through the guita percha and establish the
circuit required. We further place emery paper on the exterior of gutta
percha on which the contact point rests & is forced through, which cleans the
point & ensures the metallic contact necessary.
Our improvements consistin combining a plate or strip of gold with a plate
or strip of zinc, soldered together throughout their length. This compound
strip of metal is in a curved or other form adapted for giving motion to the
other parts of the indicator by the alteration of its form, by reason of the
difference of expansion of those metals in different temperatures. Another
improved combination of metals for this purpose consists of a strip or piece of
steel suitably united with a strip or piece of gold, & adapted to and in suitable
connection with the hand or index of the instrument.
Our improvements in the points of contact for establishing orbreaking the
electric circuit in instruments for indicating heat, cousists, first, in placing one
of the points of contact so as to bear in and rub along a groove when effected
bythe movement of the compound metal instrument before described, which
groove isformed of agate, or some similar non-conducting material, whereby
the sharp contact point will be cleaned before it arrives at the other conduct-
ing part where the circuit will be established. The rubbing of the conducting
point on the conducting surface will also tend to clean that surface & render
the electrical circuit perfect. The contact point receives its rubbing motion
from the before-mentioned compound metal strip, with which it is placed
in connection, and may be so arranged that the dial of the instrument may
indicate the temperature & its various gradations without reference to the
electric circuit. The electric circuit is so arranged in connection with an alarum
apparatus that when the instrument iudicates a given temperature it will be
discharged and give audible notice. In this manner it may be employed in
indicating fire, or to indicate steam or other heat, having arrived at too high
or too low a temperature.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Alexander Symons and Edward Burgess in the Great Seal
Patent Office on the 22nd October 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, ALEXANDER
SYMONS, of George Street, Mansion House, in the City of London, and
EDWARD BURGESS, of Clerkenwell Green, in the County of Middlesex, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-second day of April, in the year of our Lord
One thousand eight hundred and fifty-six, in the nineteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto us, the said
Alexander Symons and Edward Burgess, Her special licence, that we, the said
Alexander Symons and Edward Burgess, our executors, administrators, and
assigns, or such others as we, the said Alexander Symons and Edward Burgess,
our executors, administrators and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during the term
thereiu expressed. should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for IMPROVEMENTS IN INSTRUMENTS FOR ASOER.
TAINING AND INDICATING HEAT, AND ALSO IN THE PARTS FOR MAKING AND BREAKING
CONTACT IN ELECTRIC CIRCUITS USED THEREWITH," upon the condition (amongst
others) that we, the said Alexander Symous and Edward Burgess, our exc-,
cutors and administrators, by aninstrumentin writing under our, or one of our
or their or one of their hands and seals,should particularly describe and asser-
tain the nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal Patent Office
within six calendar months next and immediately after the date of the said
Letters Patent. .
NOW KNOW YE, that I, the said Alexander Symons, on behalf of myself
and the said Edward Burgess,do hereby declare the nature of our said Inven-
tion, and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement, reference being
had to the Sheet of Drawings hereunto annexed, and to the letters and figures
marked thereon, that is to say -
Our Invention of improvements in instruments for ascertaining and indi-
cating heat,relates, first, to the combination of particular metals tobeemployed
as the part or parts sensitive to heat of such instruments,and whereby motion
is communicated to apparatus connected with a suitable scale or dial, to afford

page_text: visible indication of the gradations of temperature, and to actuate apparatus,
whereby an audible signal or alarum will be created; this being an instrument
applicable for making and breaking the contact of electric circuits used for
this
purpose.
Our improvements consist in combining a plate or a stripof gold with a plate
or strip of zinc soldered together throughout their length, which compound
strip of metal is in a curved or other form adapted giving motion to the
other parts of the indicator by reason of the alteration of its form, caused by
the difference of expansion of those metals at or in different temperatures.
Another combination of metals for this purpose consists of a strip or piece of
steel suitably united with a strip or piece of gold, and adapted to and in
suitable connection with the hand or index of the instrument, as herein-after
described.
Our improvements in the points of contact for establishing or breaking the
electric circuit in instruments for indicating heat, consist, first, in placing one
of the points of contact so as to bear in and rub along or across a grooved
surface when affected by the movement of the compound metal instrument
before described, which groove is formed of agate, or some similar non-con-
ducting material, and whereby the contact point willbecleaned beforeitarrives
at the other conducting part where the circuit will be established. Therubbing
of the conducting point on the conducting surface will also tend to clean that
surface and render the electric circuit perfect. The contact point receives its
rubbing motion from the before-mentioned compound metal strip, with which
t is placed in connection, and may be so arranged that the dial of the instru
ment may indicate the temperature at which the alarum was discharged.
The electric circuit is so arranged in connection with an alarum apparatus
that when the instrument indicates a given temperature it will be discharged
and give audible notice. In this manner it may be employed in indicating
fire, or to indicate steam or other heat, having arrived at too high or it may
be too low a temperature.
Another improved instrument for indicating heat consists in placing two
wires, coated with gutta percha or other suitable material, either twisted
together, or otherwise establishing permanent pressure at different parts,
which, when the gutta percha becomes soft from heat, the wires will effect
metallic contact, and complete the circuit of an electric current, and thereby
actuate an alarum or indicator; or the pressing points may be sharp,and form
one part of the circuit, so that when the gutta percha becomes soft from heat,
the contact point will be forced through the gutta percha and establish the
circuit required. We further place emery paper on the exterior of the gutta

page_text: percha on which the contact point rests and is forced through, which cleans
the point and ensures the metallic contact necessary.
DESCRIPTION OF DRAWINGS.
In describing our Invention with reference to the Drawings, it will be un-
necessary to give any description of the galvanic batteries and alarum appa-
rata used for giving audible signals by means of electric currents, they being
well understood as applied for telegraphic purposes; therefore it will be suf-
ficient to say that the audible signals,herein referred to as employed in connec-
tion with this apparatus, are made much in the ordinary way (that is to say),
when the electric circuit is completed, the passing current excites an electro-
magnet attached to the signal apparatus, which magnet attracts an armature,
and therebyactson a detent and discharges a spring trainor some other motor
held in readiness by the detent, which may either ring a bell, fire a pistol, or
produce some other noise sufficiently powerful and attractive to arrest the
necessary attention.
Fig. 1 represents a plan of the compound metal strip first herein-before
referred to; and Fig. 2, a transverse section of the saine on the line 1, 2,
shewing its connection with the battery and alarum arranged to indicate
excessive heat. A, A, is the compound metal strip, beutin a suitable form, so
that, when acted on by heat, it expands and produces the effect desired; it is
fixed to a bracketb, mounted and insulated on a plate of glass c, c. The inuer
and thickest part of the strip a, as seen in plan, Fig. 1, is of gold, and the outer
or the thinnest part is of steel, or it may be of zinc; if the combination is
gold and zinc, the zinc parts should be somewhat thicker than the steel is
represented. These metals, either gold and steel or gold and zinc, are soldered
together throughouttheir length, and to afford further security to thatjunction
we further screw the two parts together by screws e, c. c. When the bent strip
is intended to contract by the application of heat, we reverse the position of
the metals before mentioned; the strip A is fixed to bracket b, and insulated
on a glass plate c. In this glass plate c the terminal of a wire from an electric
battery is secured, which consists of a piece of metal g placed side by side with
a piece of agate h or other non-conducting material; a groove is cut across
the face of these two parts, and the point of the other terminal i rests thereon.
The agate is roughed to scrub and clean the point i as it rubs over it. The
terminal point i may also recede on the glass, which is also roughed for
a similar purpose. The terminal i is attached to a small metal cylinder k
sliding in a metal socket ; the cylinder is constantly pressed and projected by
the pressure of a small spring p, which may also form an electrical com-

page_text: munication between 1 and 7. The compound stripA bears on the shoulder of,
and rests slightly on and keeps down point i on the contact surface. The wire
m proceeds from / through the alaram apparatus to one pole of the battery,
while wiren connects the other pole with the contact point y. If this instru-
ment is intended to indicate the presence of heat, to indicate and create an
alarum of fire it is placed in a position where that may possibly occur, while
the alarum is placed in a position where the person to be alarmed will hear it.
When the heat of the room wherein the strip A is placed rises higher than
that which it ought to be from natural causes, the strip will expand, as indi-
cated in dotted lines, when the terminal point i will be brought into contact
with g, thus completing the circuit of the battery and discharging the
alarum.
The pressure of spring is slight, but it induces a ready action in the
strip A; at the same time it permits it to return freely to its original position
when the temperature of the air around it becomes reduced. This apparatus
may e arranged to discharge the alarum at any required temperature, at 100"
150°, or 200° Fahrenheit, or a higher heat, if required.
Fig 3 represents a cross section, similar to Fig. 2, of a compound metal
strip as before, but differently fitted for effecting contact.. In this case the
current passes through the metal strip to a bracket 1, on which it is mounted.
This bracket is connected with the alarum and one pole of the battery by
wire m, while the opposite pole is connected with terminal by wire n, as
before. The end of the strip A has a rest pieces, which rests and travels ou
the glass surface c, c; & is the other terminal and contact point attached to the
strip A, and best seen in the partial side view, Fig. 4. This point, when the
strip A, is not subject to undue heat, recedes from the terminal 7, as seen in
Fig. 3. When, however, it is subject to undue heat, which it is necessary
should be made known, the strip A expands and carries the point into
contact with r, thereby uniting the terminals of the circuit, aud so discharging
the alarum required. The point in passing to and from 1, passes over a
groove or hollow, or there may be several of such grooves, across the path of
the pin t. In passing over these grooves any dirt collected on the pin t is
dislodged and removed, and as it advances our in a clean state, it removes
any dirt from r, and thus insures a perfect metallic contact.
The point t
cannot drop on passing over the groove u, by reason of rests, which falls on c
immediately the pressure is removed from t by passingover the groove u
The terminal points we make, by preference, of gold, or some other metal
little subject to oxidation. The strip A is adjusted to afford sufficient down-
ward pressure on the pin t to insure metallic contact, and produce the scraping

page_text: action on the terminal surfaces. In order to clean the point t, its path on the
surface of c may be roughed, in addition to the groove u, before described.
Fig. 5 represents a front elevation of an instrument for indicating different
degrees of heat by means of our improved compound metal strip; and Fig. 2 a
back view of the same. A is the bentor horse-shoe strip of metals, composed of
gold and steel or gold and zinc, which is placed in and so as to complete the
electric circuit, as before described. It is mounted on a bracket b in com-
munication with one pole of the battery, as before, the other pole of the battery
being in communication with the other terminal, which is not however repre-
sented in this Figure, but which will be readily understood from the foregoing
description. The free end c of A is placed between two small rollers d, d,
carried by a sliding rod e, supported in two bearings f.f, and free to slide
lengthwise in either direction, according as it is acted on by the metal strip A.
If the heat in which it is placed increases, the bent strip expands and opens
and draws the bar e from right to left, and when the temperature decreases, it
produces an opposite effect. To the rod e a small rod g is attached, which
connects it with an upright lever h mounted on a fixed fulcrum at i. The
lever his again connected at the bottom by a rod k to a crank arm? fixed ou an
axis m.
The axis m carries the hand n, placed in front. The motion gene-
rated in the compound bent strip A is thus communicated to the index hand,
which indicates on a dial, suitably graduated, the degree of heat to which the
strip A has been subject. The index hand is fixed to mark the heat at which
the alarum was discharged, by means of a ratchet wheel a¹on the index arborm
and pall n, which prevents the return of the hand, although the temperature
should decrease. Instead of the rods and levers for transmitting the motion
of the compound strip to the index hand, as before described, the surface over
which the free end of the strip moves may be graduated and furnished with a
stop, to retain the strip in the position to which it has been moved by the heat.
Fig. 7 represents an external view of an alarum apparatus combined, &
adapted for giving alarums of fire in situations where it is inconvenient to use
galvanic batteries, as in the holds of ships, &c.; and Fig. 8 is a partial
section, taken at right angles to Fig. 7. A is the compound metal strip, as
before described, fixed in bracket b; Bisabell for sounding the alarum, within
which the motive power is placed. The acting power consists of a train of
wheels and a spring kept wound up, which is contained within the case C;
D, D, is the bell hammer, which is mounted on an axis d, and furnished with
a detent e, seen dotted through the hammer arm; this detent rests on a roller f
mounted on an upright arm g, which moves on a fulcrum at n. When the
hammer arm is released, it has a constant tendency to rotate on the axis d

page_text: in the direction of the arrow.
on.
The hammers D1, D1, are actuated by centri-
fugal force to fly out at the rotation, and therefore to strike the edge of the bell
on the left, but on striking, recoil, as seen dotted, and allow the hammer to
proceed in its rotation, when the succeeding hammer strikes and recoils, and so
The upright army is held up to a stopi by a constant spring k. This arm
is also acted on by the metal strip A, the free end of which rests agaist a pin
fixed in g. The strip A being sufficiently powerful to overcome the force of
spring, when that strip is heated to a temperature undue from natural causes,
it forces back the arm fand spring k, which action removes the detent roller f,
and permits the action of the bell hanmer to strike the bell a succession of
blows, and so sounds an alarum. On the temperature becoming reduced, the
strip A will again collapse and bring the detent roller back to its original posi-
tion; a stop is provided, to prevent the armf moving too far. This bell alarum
apparatus is suspended by a gymble Eat the top to any suitable fastening. The
gymble prevents any jerk or shaking motion to which it may be subject,
throwing out the detent, and so discharging the alarum without due cause.
Figs. 9, 10, 11, 12, 13, and 14, represent our improved instrument for
indicating heat, and for effecting contact in electric circuits, to produce alarms
of fire, or for other purposes.
Fig. 9 represents a vertical section of a wire a coated with gutta percha,
which wire is connected with one pole of a battery; the other pole of the
battery is placed in electrical connection by a wire c with bracket b, which is
insulated. This bracket carries a strong spring d, which exerts a constant
pressure downwards on the gutta percha covering of the wire a.
It has a
knife edge e, which rests on the gutta percha. The gutta percha has sufficient
tenacity to resist the cutting action of the edge e while the gutta percha is
subject to natural temperatures only, but when it becomes warm from undue
heat of any kind, the gutta percha gives way, and the knife edge cutting
through it effects contact with the wire a, thus completing the circuit of the
battery, and so discharging the alaruin.
Fig. 10 represents a plan of Fig. 9, shewing several contact springs d, d, d,
pressing on the same wire, each of which springs may be at distances apart,
and in positions to act readily, and give warning of any undue or excessive
heat. The gutta percha should be coated with emery where the knife edge e
touches, in order that on passing through the gutta percha that edge may be
clean and suited to effect contact. The wire being in the gutta percha will
always be clean, and suited to conduct electricity on contact taking place.
Fig. 11 represents a section through two d,g, wires coated with gutta percha.
Each of these wires are in connection with opposite poles of a battery, but

page_text: otherwise insulated from each other. is a strong spring constantly pressing
on both the wires, which are twisted together; but instead of a knife edge, it
has a broad pressing surface. As before explained, the gutta percha resists
the pressure of the spring under ordinary temperatures, but yields when
subject to undue heat, at which time the spring h presses the wires d, g,
together, and effects contact, and so completes the circuit of the battery with
which the wires are connected, and discharges the alarum. The wires being
embedded in the gutta percha are kept in a clean state, and suited to make
contact for the passage of electricity.
Fig. 12 is a plan of Fig. 11, showing a number of these springs h, h, pres-
sing on the same wires, which springs may be placed near to each other, or at
distances apart, as may be required.
Fig. 13 represents a modification of Fig. 9, in which two springs i, i, oppose
each other, and nip between their end a wire coated with gutta percha. The
wire is connected with one pole of the battery, while the springs i, i, aro
connected with the other pole by wirem passing through the alarm apparatus
in its course. When subject to undue heat, the gutta percha yields and is cut
by the springs, so as to effect metallic contact with the wire 4, and complete
the circuit of the battery, which thereby discharge the alarum. There being
two contact points, greater certainty may be attained in making the contact
perfect.
Fig. 14 represents in plan an arrangement of a heat indicator; and Fig. 15
a transverse view of the same. It consists of a spring p, which has a constant
tendency to rise upwards, but is held in check by a strip of gutta percha q
placed on two pins, one fixed on a stationary bracket, the other to the steel
spring p. When the gutta percha is subjected to undue heat, and other than
arises from natural causes, the tension produced by the spring on it causes it
to give way, when the metal point enters between the arms of the pieces,
which piece s is a piece of steel finely cut or roughed on the inside like a file,
so that on point r exerting pressure to enter and spring open the arins of
piece s, s, it is scrubbed by the roughness of the cutting, which removes any
oxidation from the parts so coming in contact, and ensures a clean metallic
connection. One pole of a battery being connected with s and the other with
spring p, the circuit of the battery is completed when the parts 7 and s touch,
and which thereby discharges the alarum. Numbers of these several contact
pieces may be placed to act on the same arms and with the same battery, such
contacts parts being distributed over the area desired to be protected from fire,
while the alarum is placed at any suitable place, either present or at a distance:
but so as to alarm the person whose attention. is to be aroused.

page_text: Having described the nature of our Invention, and the manner of per-
forming the same, we wish it to be understood that what we claim as our
Invention, and desire to be protected by the herein-before in part recited
Letters Patent, is,―
First; we claim the use of the metal strip of gold and steel or gold and
zinc, combined and arranged with apparatus to produce audible and visible
indications of temperate, as herein-before described.
And, secondly, we claim the several arrangements secondly herein described
for making contact in electric circuits, and indicating heat, all as herein-before
described.
And, thirdly; we claim imparting to the contact points of electric circuits
a rubbing motion while effecting contact, to clean and otherwise prepare those
parts to produce perfect metallic contact, for the purposes and as herein-before
described.
In witness whereof, I, the said Alexander Symons, have hereunto set my
hand and seal, this Twenty-second day of October, in the year of our
⚫ Lord One thousand eight hundred and fifty-six.
Witness,
WILLIAM CLARK,
Patent Agent,
53, Chancery Lane, London.
A. SYMONS.
(L.S.)