CERTAIN IMPROVEMENTS IN APPARATUS FOR EFFEC- TUATING ALARUMS AND SIGNALS BY ELECTRICITY
Year: 1852

page_text: COMPLETE SPECIFICATION filed by the said David Lloyd Price
at the Office of the Commissioners of Patents, with his
Petition and Declaration, on the 9th December 1852, pursuant
to the 9th section of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
DAVID LLOYD PRICE, of Beaufort, in the County of Brecknock, South
Wales, Watch and Clock Maker, do hereby declare the nature of
my said Invention of "CERTAIN IMPROVEMENTS IN APPARATUS FOR EFFEC-
TUATING ALARUMS AND SIGNALS BY ELECTRICITY" to be duly ascertained
and determined in and by the following description thereof,
reference being had to the two Sheets of Drawings hereunto
annexed, and to the letters and figures marked thereon (that is to
say):
My improvements in electrical alarums relate, first, to the appli-
cation of a particular combination of metals, the difference of
expansion by heat in which produces a metallic contact at the
break of an electric circuit, which is thereby completed and gives
effect to the alarum; secondly, to improved apparatus for producing
audible alarum actuated by such electric circuit; and, thirdly, to

page_text: the application of an electrical alarum or signal on railways, in
order to indicate the approach of a trains to a station.
The compound
Fig. 1, Sheet A, represents an apparatus in front elevation, which
I denominate an indicator. This is placed in the room or other
situation in which the presence of any undue heat is required to be
indicated in some other room or place more or less distant. This
apparatus is represented in end view at Fig. 2. Fig. 3, is similar
to Fig 1, but with the front removed; and Fig. 4, a plan with the top
removed. It consists of a case a, a, of suitable material, having a
perforated or wire gauze front b, and bottom c, whereby to permit
the free ingress and egress of the atmosphere. D, D¹, is a compound
metal strip mounted and permanently fixed to a bracket e secured
to the case. This compound metal strip is separately represented
at Figures 5 and 6; it consists of a strip of steel f, united
throughout its length to a strip of zinc g, by soldering or otherwise.
For this purpose I use watch spring, which answers the purpose
extremely well; to this I unite a thin strip of hamınered zinc whose
cross section is about four times that of the steel f.
strip D, D¹, is bent to the form represented in Fig. 3, and is
sustained entirely by the end D affixed to the bracket e, the opposite
end D¹ having no permanent connection. A pin h is opposed to
the end D of the compound strip; this pin is carried by a screw i,
fitted and screwed through a piece of wood k, or other insulating
material. By turning the screw i, the pin h is caused to approach
nearer to or to recede from the metal strip D¹; this is for the purpose
of regulating the temperature at which it is desired to produce the
alarum, as will herein-after be described. The screw i has a binding
stud, whereby a wire S places it in electrical communication with
one pole of a battery E. The bracket e, has also a binding stud 1,
by which a wire R, leading to & connecting the other pole of the
battery E. The point of the pin h, which is separately represented
in Fig. 5, is tipped with gold or platina, to prevent oxidation of the
contact points; a disc or plate of gold or platina is metallically
united to strip D¹, for a like purpose. m, is a short piece of quill
fixed to D¹, in order to protect the contact points from dust. The

page_text: quill being a non-conductor, does not complete the circuit, even
though in contact with the pin h. Between the points h and' D'
being the only interruption in the circuit of battery E, it follows
that when those points are brought in contact a current of
electricity will be established, which effectuates the alarum desired
by means of the apparatus represented at Figures 7, and 8. The
difference of expansion exhibited by steel and zinc produces that
action in the compound strip D, D¹, necessary to effect contact of
D¹ with the point h. The expansion of the zinc g, under the
influence of heat, considerably exceeds that of the steel, so that any
increase of temperature in the room where the indicator is placed,
say of five or ten degrees, it becomes apparent on the compound
strip D, D¹; the zinc g being on the inside of the curve, the excess
of expansion in it beyond that of the steel f, produces a tendency to
straighten in the compound strip D, whereby the end D¹ is caused
to approach the pin 7, and, according to the adjustment of that pin,
to effect contact therewith at any given temperature. An index
is placed in connexion with the screw i, which carries a hand
or pointer, as seen at Figure 2, in order to adjust the instrument to
the circumstances required. For instance, suppose the highest
ordinary temperature of the room where it is placed is 70°, the
index hand is placed at 80° which will adjust the contact point, so
that on any undue heat occurring in the room by reason of fire, the
expansion of the compound strip will produce contact and complete
the circuit of the battery on the air in the room arriving at the
higher temperature, and instantly give notice by its action on the
alarum apparatus.
The alarum may be produced either by the firing of a pistol, or
ringing a bell, or both. Fig. 7, shows a front view of a pistol
alarum in connection with the indicator; Fig. 8, a side view of
the same. The pistol is attached to a board F, by a pin n, on which
it turns when raised for loading. It is held in position by a bolt
and bracket embracing the barrel. The pistol is of an ordinary
character, with the trigger o much elongated, extending down into
the box containing the apparatus for discharging. This apparatus

page_text: consists of a temporary magnet G, the coil on which is in the
circuit of the battery E. For the sake of distinction the wire R,
from one pole of the battery to the break in the circuit, is in red
colour, while the wire S from the other pole it is represented in
blue. H, is a detent lever carrying an armature W, which is
opposed to the poles of the magnet G, and is attracted thereby when
induced by the passage of the current. The detent p is formed to
take only a slight hold of lever I, by the pendent end. This lever
is permanently pulled by a spiral spring K to the position shewn
by dotted lines. During the movement to this position a pin q
strikes the trigger o, and so discharges the pistol, which is loaded
and capped in the usual manner. This discharge takes place when
the air surrounding the "indicator" attains that temperature at
which the "indicator" has been set, and at which point contact
between the compound strip D' and the pin h occurs; this instantly
completes the circuit, thereby inducing the magnet G, whose at-
tractive force is exerted on the armature W, which is drawn towards
the magnet, causing the detent p to release the lever I.
Fig. 13, exhibits a house fitted with the alarum F, in one room,
and in communication with all the "indicators" X, X, in the several
compartments. The battery E is placed in any suitable position,
and includes in its circuit the alarum apparatus F, and all the
indicators X. The wires from the opposite poles are represented
in different colors, one of which has communication with the stud 2
of bracket e of the whole number of indicators X, X, while the
other is in like communication with the screw pin h. The con-
nection is broken at each indicator, these terminal points being
effectually insulated, there is therefore no electrical circuit of the
battery so long as the compound strip D remains uninfluenced by
heat; the undue expansion of any one of the metal strip D, in
any one of the rooms, instantly establishes the circuit, and
discharges the alarum. The current wires may be laid throughout
the house in a manner similar to bell wires, taking care that they
are in a perfectly insulated condition, the one from the other.
The battery I employ is that known as "Smee's," but in which

page_text: platinized silver is used as the negative plate, and having a trough
of mecury into which the zinc plate dips, which maintains a per-
manent amalgamation, and conduces to a constant action for a long
period of time.
Instead of firing a pistol as the alarum, I sometimes employ an
alarum bell, represented in front elevation at Fig. 9, and in side
elevation at Fig. 10. It consists of an temporary magnet G, placed
in the circuit of the battery, which when induced acts on the
armature of a detent lever S. The detent pin t in this case takes
into a toothed wheel u, fixed on an axis v, which axis has a
tendency to rotate by reason of a weight w, suspended by a chain
gearing in a chain wheel x, and imparts its motion to the axis v.
In order to permit the winding up of the weight w, the wheel
is loose on the axis, and drives in one direction by means of a
ratchet wheel y, taking on to a pall attached to the wheel u.
An escape wheel z (separately represented at Figures 11 and 12)
is fixed to the wheel u, and gives oscillatory motion to the bell
hammer shaft M, by means of pallets 1, 2. These pallets are faces
inclined in opposite directions, and are acted on alternately by the
escapement teeth; the upper face 1, causing an oscillation to the
right of the shaft M, and the consequent stroke of the bell'; the lower
face 2, produces the opposite oscillation of hammer shaft, by the
contact of the escape wheel tooth and alternate stroke of the bell.
This is repeated until the weight runs down. Instead of a weight, I
sometimes employ a coiled spring as the sustaining power, as well
understood in clockwork.
Both these alarums may be placed in one case, and simultaneously
discharged by the action of one magnet, as arranged and represented
in dotted lines, Fig. 7, which indicate the position of escape wheel
and detent lever.
These "indicators" are adapted for any situation where fire may
be apprehended, as in all warehouses and other buildings, the
electric circuit being formed with an alarum suitably placed at any
distance where it is required to produce the signal; also in railway
carriages and in the holds of ships, with an electrical communication
with the alarum in the cabin.

page_text: The battery employed at on boardship, may consist simply of a
water-tight case, placed below the water line, and having free com-
munication with the external water. The positive and negative
plates are immersed in this case, and arranged so as to constitute a
galvanic battery.
Fig. 14, Sheet B, represents the fire "indicator" placed in
railway carriages, having communication with an alarum F, on the
engine; or the apparatus may be caused to affect the plug of tap
in the steam passage of the whistle Y, which may be acted on by
a lever in a manner similar to that represented with reference to the
trigger of pistol; the passage being thus opened, sounds the whistle.
By effecting the contact at the "indicator" break by hand, the
same apparatus may also be used as a means of communication
between the passengers or guard and the engineman. The connecting
wires R, S, properly insulated, are carried throughout the train, as
shewn, and connected between the carriages by a coupling stud,
attaching the terminals of the wires, which are coiled in the form
of a spring as shown at Fig. 15, in order to afford the necessary
play.
Fig. 16, Sheet B, is a modification of the "indicator," in which a
straight compound strip D is used; the zinc g is placed on the
upper side of steel f, which zinc, by its expansion in excess of the
steel, deflects the compound strip D, causing the free end to dip. In
this case the contact is effected by a mercury cup U, placed in
communication with one pole of the battery, into which cup
the amalgamated pin 3 descends, thus completing the circuit, and
acting as before.
Fig. 17, Sheet B, is another arrangement, showing the alarum
and indicator in one. In this case the compound strip is arranged
in a circle, which form embraces a considerable length of strip D, in
a small space, and producing a very sensitive instrument. The zinc
9, g¹, in the compound strip is divided into two parts g, g¹; that, g,
nearest the free end is placed on the inside of the steel f, which
expands that arc by heat as before; while the other portion, or that
nearest the fixed end, is on the outside, and therefore contracts that

page_text: portion of the circle. The combined action of this arrangement
depresses the pin 3, and dips it in the mercury of cup U, where
much dust or dirt is liable to get at the indicator; the mercury cup
is the preferable mode of effecting the desired contact.
.
Another application of an electrical alarum, according to my im-
provements, refers to a mode of signalling the approach of a train
towards a station, when at any required distance from that station.
Fig. 18, B, represents the wheel of a railway carriage about to act
on the apparatus, whereby the electric circuit is completed, which
gives effect to the alarum as before described. This alarum is placed
at the station towards which the train is approaching. Figure 19, is a
transverse section of the apparatus and rail; and Figure 20, a lateral
section of the same. It consists of a lever A, mounted on a shaft
B. The short end of lever A is permanently acted on by a spring C,
so to raise the free end of the lever, the upward motion of which is
limited by a stop and spring D. The long end of the lever A,
carries a foot piece F, which occupies a position close too and at a
little elevation above the rail, so that the wheels of a train in
passing will infallibly come in contact therewith, and cause the
lever to be depressed. The depression of long end of lever A
causes the bent rod G to dip into the mercury cup H, which unite
the break in an electric circuit, and so discharges the alarums. L
is the alarum which is placed at the station with the battery, the
one pole of which is connected by the blue wire S, embracing the
magnet of the alarum in its circuit, and passing thence to the
binding stud on the lever A, while the other pole is connected with
the mercury cup by the red wire R. These terminal points, and the
circuit throughout, is of course properly insulated. The lever
apparatus is placed at any distance from the station, according to
the time required to elapse between the signal and the arrival of the
train.
Having described the nature of my Invention, and the manner in
which it is to be performed, I would have it understood that what I
claim is, first, the combination of zinc and steel, described in the
compound strip D, D', as an instrument which by its expansion

page_text: effects contact at the break of an electric circuit, for the. purpose of
discharging an alarum in case of fire, as herein-before described.;
secondly, the several arrangements of parts constituting the
indicator described, and also the arrangements of alarum apparatus
described; and, thirdly, the apparatus described for giving notice
by alarum of the approach of a train to a station.
In witness whereof, I, the said David Lloyd Price, have here-
unto set my hand and seal, this Ninth day of December,
1852.
DAVID LLOYD PRICE. (L.S.)