Year: 1887

page_text: Date of Application, 12th Mar., 1887:
Complete Left, 8th Nov., 1887
Complete Accepted, 9th Dec., 1887
We, HENRI STEVEN PETIT and HENRI STEVEN BRESSON, both of Vittoria, Spain,
Engineers do hereby declare the nature of this invention to be as follows:-
This invention relates to apparatus which, when a sudden elevation of temperature
occurs near it, makes or breaks electric contacts and thereby causes a visible or
audible signal to be given at a distance. For this purpose, a bar of metal of
considerable transverse section has stretched on and in front of it a fine wire of
the same metal. The middle of this wire is pressed against by a spring and carries
an electric contact piece which, in the ordinary condition of the apparatus, is either in
contact or out of contact with conductors leading to an alarum at a distance. When
changes of temperature take place gradually, both the bar and the wire expand or
contract equally, and the electrical contacts remain unaltered. But, when there is a
rapid elevation of temperature near the apparatus, the wire expands more quickly
than the bar, and the spring pressing on its middle gives it such flexure that the
contact piece which it carries is moved out of or into contact thereby opening or
closing the electric circuit of the alarum. The tension of the wire and the force
of the spring, as well as the position of the contacts, are adjustable by screws so
that the apparatus may be made more or less sensitive; also the bar may be more
or less covered by non-conducting material for the same purpose.
Dated this 19th day of March 1007
ABEL & IMRAY,
Agents for the Applicants.

page_text: We HENRI STEVEN PETIT and HENRI STEVEN BRESSON both of Vittoria, Spain,
Engineers, 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 apparatus which, when a sudden elevation of temperature
occurs, near it, makes or breaks electric contacts and thereby causes a visible or
audible signal to be given at a distance. For this purpose a bar of metal of
considerable transverse section has stretched on and in front of it a fine wire of
the same metal. The middle of this wire is pressed against by a spring and carries
an electric contact piece which in the ordinary condition of the apparatus is either
in contact or out of contact with conductors leading to an alarum at a distance.
When changes of temperature take place gradually both the bar and the wire expand
or contract equally and the electrical contacts remain unaltered. But, when there is
a rapid elevation of temperature near the apparatus, the wire expands more quickly
than the bar, and the spring pressing on its middle gives it such flexure that the
contact piece which it carries is moved out of or into contact theroby opening or
closing the electric circuit of the alarum.
The accompanying drawings illustrate a mode of performing this invention.
Fig. 1 is a front view or elevation of tho instrument showing connections with the
alarum.
Fig. 2 a longitudinal section along line a-b.
Fig. 3 a cross section along line c-d of the apparatus.
Figs. 4 and 5 are detail views.
A is a board preferably of wood carrying secured to it the two wooden rails B B
the opposing surfaces of which are hollowed out as shown in Fig. 3 the edges serving
as a support for the metal plate C. Air is admitted freely to the plate C through
openings or perforations S in the rails B B-C is the metallic plate or block serving
as a compensator of expansion. This block is integral with the two pulleys or
studs DD at its extremities and with the box or casing X at its centre. is a
spiral spring supported by or in the box X in the centre of the plate C and abutting
on and supporting at its upper end a metallic contact plate G (Fig. 5)-H is a metal
wire wound about the grooves of the pulleys or studs D D and passing over the
contact plate G-J is a metal plato fixed on the box X but electrically insulated
therefrom in the known manner. The said plate J carries in its centre a contact set
screw K. and is in electrical communication through the wire E with the terminal M
holding one of the conducting wires R-N is the corresponding terminal for the other
conducting wire T and is in communication through the wire L with the box X.
PP are plates connecting at their ends the rails B B.
The apparatus is in connection through the wires RT with an electric battery Y a
switch or commutator Q and one or more alarms U.

page_text: In a normal condition, the metal wire H having a fixed tension maintains the
plate G separated from the set screw k when the temperature varies in an ordinary
measure, the bar expands more or less so as to compensate the expansion of the
wire H and maintain the tension thereof.
But in case of a firo in the locality in which the apparatus is placed and great heat
rapidly produced, the wire H expands more rapidly than the bar C consequently the
spring being no longer retained by the wire H pushes the plate G against the
regulating screw K, thus forming electrical contact, completing the circuit and
actuating the alarm.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what we
claim is
In electrical fire alarums
1. An electrical contact device restrained by tension adapted to be released by quick
rises of temperature for the purpose set forth.
2. The combination with an electrical contact device of a wire adapted to restrain
said device by tension, and a bar carrying said wire adapted to maintain tension in
said wire during slow changes of temperature for the purpose set forth.
Dated this 8th day of November 1887.