Improvements in Fire-alarms.
Year: 1889

page_text: Date of Application, 14th Nov., 1889
Complete Specification Left, 7th Aug., 1890-Accepted, 13th Sept., 1890
PROVISIONAL SPECIFICATION
Improvements in Fire-alarms.
I, BENJAMIN PRYOR STOCKMAN of 8 Poets' Corner Westminster, Civil Engineer, do
hereby declare the nature of my invention for "IMPROVEMENTS IN FIRE-ALARMS
"to be
as follows namely
The object of this invention is to provide a certain and reliable means of giving
prompt alarm upon the outbreak of fire, and my invention consists of an apparatus
combining the known method of pneumatic signalling with a system of electric and
magnetic apparatus.
As regards the pneumatic part of the system, I adopt the usual tubing or piping
such as is used for pneumatic bells or speaking pipes; and 1 construct a drum or
air-hox (afterwards called the "box") of a special form, being unlike air-chambers, as
hitherto used, for the purposes of signalling. I avoid the form known as an "inverted
cone " and I construct the box specially to render it most sensitive to heat so that it
shall receive the earliest impression from the heated air where a fire broaks out, also
the transmission of heat from the outside to the inside of the box; and, further, that
the maximum impulse shall be given to the column of air in the tube.
To offect these several results, I make the box parallel, as a sardine box, or it may
be circular and parallel, or in the form of a direct cono or kettle-drum with its
parchment-head downwards. But, whatever its form, the broad surface is downwards
or outwards, and made of very thin material such as bladder-skin, parchment, or other
membranous material; or thin metal, strained tightly; the other part of the box being
sufficiently rigid to withstand the strain without yielding.
When using a large box, to prevent the thin plate from sagging or bulging, I
support it at intervals by skeleton frames of wiro fastened both to the thin plate and
the top of the box: thus I concentrate the expansive force which is made to exert
itself in the direction of the tube with as little loss as possible.
To the rim of the box the tube is attached by a sealed joint.
At the further end of the tube is a valve apparatus, which consists of a small
cylinder of brass or any hard material, sealed at bottom; the tube being jointed at
right angles to it. The top of the cylinder spreads into a bell-mouth which is covered
by a thin piece of india rubber or other thin elastic material, stretched tightly. In
the centre of this cap, I fix a short light rod (piston-rod) of wire or such as might be
made out of a lucifer match, and guided by a cross-piece with a hole in it.
The impulse given to the column of air in the tube, bulges the elastic cap and
thrusts forward the piston-rod.
Instead of the capped bell mouth I sometimes use a piston in the cylinder.
Although I have only described one tube and one cylinder valve, I may increase
the system to any number of tubes, valves, and boxes, as may be required.
The above description refers to the pneumatic part of my invention; and I now
describe what I term the electric and magnetic part, and which really comprises the
indicator and connections.
I prepare a small table or slab made of wood, vulcanite, or such other suitable
material, as the base or stand; and upon this I support the cylinder valves. On the
saune stand I fix a horizontal axis supported on bearings or uprights; and on this axis,
which may be made of wire, I thread a number of small semaphore blades, by means
of holes in their ends; and i keep these blades steady by collars spacing them. The
blades are strung loosely, so that they may freely turn over from a vertical to a
horizontal position. They may be made of any hard material; but on one edge a
piece of iron is fixed, and on the opposite edge a piece of brass or good con-
ducting metal. In contact with the iron edges of the blades, are as many small

page_text: electro-magnets each having a battery to itself; and the blades are held in the
vertical position by the magnets while a current flows through the coils.
On the opposite side of the table, I fix two horizontal and parallel bars of any good
conducting metal, and so placed that, when all the blades are in a horizontal position,
their brass edges rest on these bars, to which conducting wires are connected, forming
a battery circuit which may extend to any distance outside the premises. In this
circuit I place two or more gongs, one being attatched to the indicator, and the other
at a distant station.
"
"
All the wires from the small electro-magnet-batteries terminate in a switch-board,
or a grid of parallel rods; and the closing of each circuit is by a cross piece
hinged to one rod at one end, the other lying on the next; and the piston rods lift the
ends resting on the rods, and break contact, when the blades inmediately fall on to
the two horizontal bars, and close the gong circuit, and the gongs ring.
By loading the hinged cross pieces by a sliding weight, the resistance to the impulso
to move the pistons is so adjusted as to suit any degree of heat, so that false alarms
can be obviated.
Each blade has, marked upon its surface, the number or other description of the
apartment, and which is readable when the blade has fallen to the horizontal
position.
The indicator is placed in any convenient apartment for the inspection of the
inhabitants, or a night watchman. The box is fixed to the ceiling or any convenient
elevated situation, and the tubing may be fixed along the cornice or walls or other
suitable place, either concealed or exposed.
The outer electrical, and inner indicators, may be combined in their action or
separate and independent.
Sometimes, to save battery renewals, 1 reverse the operation of breaking contact, in
lifting the hinged cross pioces by the piston rods, and make contact instead. In
which case the blades are held vertically by balance, and pulled over their centre of
gravity by the magnets causing them to fall.
In a small installation or short distance to the indicator I may dispense with the
use of the electro-magnets, the thrust of the piston rods acting directly on the blades
to throw them over.
-The uses of my invention extend to all buildings, ships, railway trams, collieries, and
in fact to all places where fire may occur: and, in its distant signalling as for ware-
houses where there are no watchmen or resident persons, it is particularly applicable.
November 14th 1889.
B. P. STOCKMAN, M. Inst. C).E.
COMPLETE SPECIFICATION.
Improvements in Fire-alarms.
I BENJAMIN PRYOR STOCKMAN of 3, Poets' Corner Westminster, Civil 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:
The object of my invention is to provide an automatic means of giving prompt
alarm upon the outbreak of firo, and my invention consists of an apparatus combining
the known method of pneumatic signalling with electricity.
Reference is to be had to the accompanying drawing, which forms part of this
Specification, and on which ..

page_text: and I attach, to one end of the tubing, by an air-tight joint, an air-box (A on the
drawing), which may be fixed to the ceiling of a room in any convenient position,
either concealed or exposed. The air-box is so constructed as to receive the earliest
impression from the heated air, where a fire breaks out, and to allow of the quickest
transmission of heat from its outside to its inside; also to concentrate the expansive
force of the heated air, so as to confine it to the column of air in the tubing.
To effect these purposes, I make the air-box as follows, namely: in the form of a
parallel disc, as shown in the drawing, a direct cone, or an ornamental form; com-
prising a stiff rim, or shell, covered with very thin metal, or membrane, strained
tightly like a drum-head. The air-box is hermetically sealed, except at its only vent, at
the joint with the tubing (c); and I prevent the bulging of the thin plates, or covers,
by tying them together with wire, or skeleton framing (shown at d).
A space is left (b) between the upper surface of the air-box and the ceiling.
The tubing may be extended to any part of the premises, in any ramifications;
but its end, remote from the air-box, terminates with an instrument called an
"indicator" (A on drawing); and which indicates that a fire has broken out in the
room where the air-box is situated.
The indicator (shown to be enclosed in a box W resting on a shelf r), is constructed
in the following manner: a slab or table, made of vulcanite, wood, or any hard
material, forms the base; on this slab, at one end, stands a short tube or cylinder (ƒ)
having a spreading flat, bell-shaped, top (g) the lower end of the cylinder joined
to the system of tubing (c) the whole of which is in communication with the air-box.
Over the broad bell-shaped end of the cylinder is a covering, or cap, of thin sheet
india-rubber or other elastic membrane (g) tied on perfectly air-tight.
The heat, due to fire, expands the air in the air-box; and, the expansive force,
presses on the column of air in the tubing, setting it in motion, and causing it, finally,
to strike the underside of the india-rubber cap (9) which expands it into a convex
form. And it is this dilatation, of the india-rubber cap, that effects all the succeeding
operations. Instead of the spreading india-rubber cap, I may, however, use a piston,
in the short cylinder (S), similar to a cornet piston.
.
On the slab alluded to I fix a light metal lever (A) above the india-rubber cap, and
delicately balanced on a fulcrum. Just over the centre of the india-rubber cap
there is a vertical adjusting screw (i) in the lever, having a round button (k) on its
under end and a milled head at top, the tail end of the lever is also formed into a
horizontal adjusting screw (m) and has a heavy nut (n) working easily upon it. The
position of this nut regulates the leverage and consequent pressure upon the button (k)
offering more or less resistance to the rising of the india-rubber cap; and a similar
effect is produced by raising or lowering the vertical screw (i) as, the greater the
space, or distance under the button (k) the higher must the india-rubber cap rise to
meet it. Both these mothods may be used together, or separately, to regulate the
pressure and, consequently, the heat determined upon, to act on the air-box to give
an alarm.
I also fix on the slab an upright (1) forming a joint, or fulcrum, on which is
centred a semaphore arm (p) on the face of which may be marked the number
or other description of the room wherein the air-box is fixed. The semaphore
is held in a vertical position, until released by the action described, when it
falls over into a horizontal position, as shown by the dotted lines on the drawing;
and, to effect this movement of the semaphore, I adopt one or other of the three
following methods:
First. I use an electro-magnet to hold the semaphore; when, by the action of the
india-rubber cap and button (acting as a piston) electric contact is broken; and, the
magnetism ceasing, the semaphore falls.
Second. I reverse the operation, by making the magnet come only into operation to
pull the semaphore over; in which case the lever and button, instead of breaking
contact, make contact. This arrangement might be preferable, to prevent the
exhaustion, and too frequent renewals of the magnet batteries; and,
Third. (Which will be more generally used) the electro-magnets are dispensed with

page_text: altogether. In this case the india-rubber cap, by means of the button and lever, acts
upon the semaphore direct; that is to say, the semaphore is held in its upright
position by means of a delicately cut notch, and corresponding catch, at the
end of the lever (9) which, when lifted, releases the semaphore, and allows it to
drop.
I now describe the electrical part of the apparatus.-Transversely, on the slab
already alluded to, I fix two parallel rods, (the ends are shown at oo) of copper, or
other good conducting metal. These are supported above the surface of the slab, and
rigidly fixed to it; and from each of these rods is attached a conducting-wire, passing
through, and under, the slab, and fixed to terminals for attachment to the battery
wires (u).
The semaphore, when fallen to the horizontal position, rests upon the two parallel
rods (oo) but the edge of the semaphore is provided with a piece of good conducting
metal, let into a recess; and rocking on a centre or fulcrum (s) so that, in falling on
to the parallel rods, it makes perfect contact with both; and thus closes the electric
circuit. In this electric circuit, and in any place desired, are fixed electric bells or
gongs; one (t) may be fixed in the indicator-box; another where the air-box is fixed,
and others at the nearest fire-brigade stations, or wherever the electric circuit is
extended.
Although I have only described one sot of apparatus there may be several, for
example, there may be an air-box in each of any number of rooms, and a correspond-
ing number of tubes; and, on the slab of the indicator, the same number of capped
cylinders, levers, and semaphores; or, for convenience, when a great many signals aro
required, as for large hotels, there may be several slabs, each containing a certain
number of semaphores, &c.
The uses of my invention will be, for public and private buildings, industrial
schools, barracks, warehouses, stores, ships; and, in fact, for all places where fire may
occur.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, 1 declare that what I
claim is:
1. The method of constructing the apparatus as described.
2. The form of indicator as described, and the making electric contact by the fall
of the semaphore arm, thus closing the gong circuit.
3. The use of electro-magnets for actuating the motion of the semaphore arms.
4. The combination of pneumatic and electric action, substantially in the manner
herein before set forth and described.
Dated this 7th day of August 1890.