Improvements in Electric Alarm Apparatus.
Year: 1887

page_text: Date of Application, 4th Aug., 1887
Specification Accepted, 20th Sept, 1887
Improvements in Electric Alarm Apparatus.
I THOMAS MORRIS KNIGHT of Philadelphia, State of Pennsylvania, United States
of America, but temporarily of 8 Craven Street, Strand, London, Merchant 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 means for rendering structures of various
kinds secure from danger arising from abnormal conditions-such as fire, water, or
burglars which injuriously affect the structure or its contents.
The invention consists in a fabric of peculiar construction, such as is hereinafter
described.
Figure 1 represents the fabric as it is first made. Figure 2 represents the fabric
after it is disposed in place. Figure 3 is a section in line xx.
In the annexed drawings, the letter A indicates any ordinary fabric, in which are
placed bare metal wires a. The preferable way of forming this fabric is by weaving.
As the textile fabric which joins the base is made in the loom, wires a are disposed so
as to form threads of the warp. These wires a are placed any given distance apart
say two inches. The fabric is then woven in the usual way, the wires becoming part
of the same, as shown in Figure 1. The wires may be incorporated in other ways,
such as laying the wires in a series side by side between two pieces of fabric, and then
securing the whole by paste or otherwise; but I prefer the first method. The fabric
thus formed is cut into lengths suitable for use, say, for flooring of a room or the
ceiling. The fabric thus cut is put in place like strips of wall-paper, arranged in one
direction of the room, forming a covering C. The protruding ends a¹ a¹ &c., are
soldered together in loops, and form one continuous wire. Then a sheet of thin
paper B is placed on this covering of wire fabric. Over this sheet of paper B is placed
another covering D of the wire fabric this being disposed so that its wires a² run
transverse of the wires a of the first covering C. The ends c c &c. of this second
covering are soldered together, forming a continuous wire through this second
covering. Then this continuous wire connected at one end-say e-with the other
continuous wire in the first layer through a resistance-coil, say at. Then one of the
layer-wires is grounded, as at e¹, and the other is connected with the line-wire
ID 677

page_text: which runs to the battery (the other pole being connected to earth in the ordinary
way) and has a galvanometer connected therewith. This covers the floor with a mesh
or net-work of wire which is in circuit.
Now, should any accident happen to the wire-say it is cut for burglarious purposes,
or by fire the circuit is broken, the galvanometer-needle falls open, and an alarm is
given through an electric or other bell in the known manner. Should any one walk
across the room, or pressure be applied so as to press one series of wires upon the others,
immediately the current is short-circuited, the resistance-coil is cut out, and the
galvanometer-needle gains its position in the angle, and the alarm is also given.
Should water by any mishap flow in, the two series will contact and also short circuit.
It is therefore obvious that whether the wire fabric be cut or contacted in any way an
alarm will be given as above described.
It is obvious that the two coverings of wire fabrics need not be placed so that
the wires are at right angles, but simply so that they shall cross one another at
any angle.
This fabric is to be used with any structure such as a house, a safe, a trunk &c. by
simply putting it in place, as above described.
•
In Figure 4 is shown diagrammatically another way to use the fabric, especially to
indicate leakage of water. Here only a single thickness is used-say on the ceiling.
Instead of looping the ends, as described, the alternate ends m m¹ of the wires on
each side are connected with the wires p q which connect with the battery s and gong t.
This forms an open circuit in the covering. Now, if water should leak, in a connee-
tion is made at some point, the circuit is closed, and the alarm sounded.
Where this fabric is designed for use in places where the alarm would only be
sounded by breaking the wires, these may be covered before inserting them in the
fabric but I prefer them bare. However, my invention includes in its scope any
kind of wire, covered or uncovered.
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. As a new article of manufacture, a fabric to be used on structures to render an
alarm in case of abnormal conditions, the said fabric consisting of woven or like
fabric containing a series of bare wires formed therewith, as set forth.
2. As a covering for structures to insure alarm in case of abnormal conditions, the
two layers of wire fabric constructed as described, in combination with the interposed
layer of paper or analogous bibulous substance, the series of wire in one layer crossing
those in the other, as set forth.
3. As a new article of manufacture, a fabric to be used on structures to render an
alarm in case of abnormal conditions, consisting of a woven or like material containing
a series of wires formed therewith, as set forth.
Dated this 4th day of August 1887
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London,
Agent for the Applicant.

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