IMPROVEMENTS IN APPARATUS FOR COMMUNICATING SOUND SIGNALS
Year: 1861

page_text: PROVISIONAL SPECIFICATION.left by André Desiré Martin and Prosper
Verdat du Trembley at the Office of the Commissioners of Patents, with
their Petition, on the 6th March 1861.
We, ANDRÉ DESIRE MARTIN and PROSPER VERDAT DU TREMBLEY, of Rouen,
France, Civil Engineers, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN APPARATUS FOR COMMUNICATING SOUND SIGNALS," to be as
follows:-
These improvements consist in the novel modes or methods of arranging,
combining, and employing the apparatus herein-after described for the purpose
of enabling either the compression or exhaustion of air to be made available
as an agent or medium whereby the transmission of sound signals may with
great facility and certainty be effected.
Instead of communicating sound signals as has generally heretofore been
done by means of bell pulls, bell cranks, wires, rods, springs, and similar
contrivances acting upon bells or alarums, or instead of any other of the
ordinary means of transmitting or communicating sound siguals, we substitute
therefor the following novel arrangement of apparatus and modes of using or
employing the same. When it is wished to transmit sound signals by the
agency of compressed air, according to our Invention, we prefer to proceed as
follows: We form two hollow chambers or boxes, of metal or other suitable
material, each provided with an internal elastic diaphragm of vulcanised
india-rubber or other elastic material; to the central portion of each of these
diaphragms is connected, by metallic plates of suitable form, and so arranged

page_text: as to render the joint formed at this part of the diaphragm perfectly air-tight,
a rod which partakes of the motion of the elastic diaphragm of its respective
chamber. The rod of one chamber or vessel passing through a suitable collar
thereupon may, in order to produce the necessary sound, be caused to act
upon the "double detent" of an "office gong," or other similar sound signal,
wherein the sound is produced by direct pressure upon a rod or spindle acting
upon the disengaging and striking parts of the sound signal or apparatus. The
rod attached to the diaphragm of the other or transmitting chamber serves to
receive the pressure directly when it is desired to communicate a signal, and
by the action of the contained elastic diaphragm in compressing the air beneath
it, forces up the elastic diaphragm and rod of the other chamber. The elastic
diaphragm in the interior of the transmitting chamber being secured at the
top thereof, and the elastic diaphragm of the other chamber being at the
bottom thereof, each of the chambers is provided with an opening forming a
junction piece by which the two vessels or chambers are connected together
by means of air-tight tubing, either in metal and rigid, or flexible and made
of gutta percha, vulcanised india-rubber, or other suitable impermeable mate-
rial. The top cover of each of the chambers or vessels is perforated with
suitable apertures for the inlet or discharge of air when the apparatus is at
work. The capacity of each of the chambers is proportioned according to the
distance between the points of communication; the diameter of the elastic
diaphragms and of the central plate upon which each of them rests, is propor-
tioned according to the amount of resistance to be overcome in the ringing or
sounding apparatus. Now, in transmitting sound signals by means of the
apparatus as just described, upon pressing down the rod orspindle attached to
the diaphragm of one chamber, the diaphragm and rod of the other chamber
sympathetically ascends and puts in action the sounding apparatus by means
of simple pressure, in manner herein-before described. But if, instead of
actuating the ringing or sounding apparatus through the agency of compressed
air, it is preferred to take advantage of the action of the exhaustion of air
producing a vacuum more or less perfect on one side of an elastic diaphragm,
it will only be necessary in such case to reverse the functions of the working
parts of the two seperate apparatus. The rod of the apparatus which before
received the pressure direct, and so put in sympathetic action the diaphragm
and rod of the other apparatus, will now give motion to the working parts
actuating the hammer or striker of a sound signal; for, upon pulling or
drawing up the rod attached to the elastic diaphragm of what will now be the
transmitting apparatus, a vacuum more or less complete will be formed under-
neath the elastic diaphragm of the other apparatus, the atmospheric pressure

page_text: on the upper surface of the diaphragm causing the same to descend with a
force proportionate to the vacuum formed beneath it. The rod with which
this diaphragm is connected will, in its descent, actuate the escapement lever,
springs, or other similar mechanism for causing the hammer or striker of a
bell, alarum, or other sound signal to be put into action and produce any
required number of distinct audible signals. In either case, namely, whether
sound signals are produced through the agency of the compression or through
the exhaustion of air, instead of the transmitting chamber or apparatus from
which signals are communicated, there may in some cases be substituted
instead therecf a combined suction and forcing syringe, which shall in the one
case, by creating a partial vacuum below the elastic diaphragm (fitted in the
upper interior portion of its containing chamber), cause the same to descend;
and, in the other case (the elastic diaphragm being secured to the lower
interior portion of its containing chamber), when the piston of the syringe is
forced down, the elastic diaphragm and its connections will be sympathetically
caused to ascend. Suitable openings and valves are provided in the syringe
for the admission and exit cf air. A spring or other suitable contrivance may
be provided in the interior of the syringe to enable the piston to resume its
normal position at the end of each stroke.