IMPROVED MECHANICAL TELEPHONE
Year: 1884

page_text: I WILLIAM PHILLIPS THOMPSON Fel. Inst. P. A. of 6 Lord Street Liverpool
in the County of Lancaster and 323 High Holborn, in the County of Middlesex,
Civil Engineer do hereby declare the nature of the said Invention for "IMPROVED
MECHANICAL TELEPHONE" to be as follows:-
The object of this Invention is to produce a mechanical or acoustic telephone, so
called, which shall more perfectly reproduce the sounds of speech at a distance
within the limit of mechanical transmission of sound waves.
The telephone is made preferably about eight inches in diameter, constructed in
two parts with an internal recess. The two sections of the case are fastened
together by screws at top and bottom, which also secure the edges of the composite
diaphragm, thus allowing sufficient space on each side of said diaphragm to admit
of its vibrating properly. A circular opening through the front of this case or
shell, allows the voice of the speaker to impinge directly upon the face of a
metallic disc which rests against the composite diaphragm. A similar opening
through the base of the case allows space for the placing of the sound collector as
hereinafter described.
The diaphragm is composed of very thin strips of wood, which for convenience
or utility may be interwoven, as in what is commonly known as basket work, and
of which two layers may be used, firmly pressed together with a filling of wood,
paper, cloth, or other fibrous substance between them. The strips of wood are not
necessarily to be arranged in the manner aforesaid. They may be laid parallel to
each other and cemented or arranged in any other manner necessary to form a
diaphragm which shall be practically continuous although composed of several
parts.
A circular metallic disc rests upon the diaphragm opposite the centre of the
opening. A hole through the centre of this disc admits of the passage of the
conducting line wire, the end of which is securely wound around a pin, of
sufficient length to allow its ends to rest on the surface of the disc and thus

page_text: prevent the wire from slipping out while at the same time the tension of the line
wire presses the disc firmly against the diaphragm.
Behind the diaphragm is placed a sound collector, which may be constructed of
wood or other resonant material. A hole through the centre of this sound collector
admits of the passage through it of the line wire upon which it moves freely. The
base of the sound collector is slightly concaved, so that its edges alone touch the
diaphragm, against which it is pressed by means of a spiral spring at its base, one
end of which is secured to the line wire while the other acts against the base of
the sound collector, the line wire passing freely through the centre of the spiral.
Dated this 16th day of June 1884
WM P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
Agents for the Applicant.

page_text: 1, WILLIAM PHILLIPS THOMPSON, Fel. Inst. P. A. 6 Lord Street, Liverpool,
Lancashire, and 323 High Holborn, Middlesex, Civil Engineer, do hereby declare
the nature of the said Invention for "IMPROVED MECHANICAL TELEPHONE" 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 this Invention is to produce a mechanical or acoustic telephone so
called, which shall more perfectly reproduce the sounds of speech at a distance
within the limit of mechanical transmission of sound waves..
In the accompanying Drawing the construction of such an improved telephone
is illustrated. Figure 1 is a sectional view of the telephone, and Figure 2 is a plan
view of a portion of the back of the instrument, showing the construction of the
diaphragm. The telephone is made preferably about eight inches in diameter,
constructed in two parts, with an internal recess F F. The two sections of the
case are fastened together by the screws B B, which also secure the edges of the
composite diaphragm D, thus allowing sufficient space on each side of said
diaphragm to admit of its vibrating properly. A circular opening through the front
of this case or shell, allows the voice of the speaker to impinge directly upon the
face of the metallic disc a which rests against the composite diaphragm D.
A similar opening h h through the base of the case allows space for the placing of
the sound collector as hereinafter described.
The diaphragm D is composed of very thin strips of wood, which for convenience
or utility may be interwoven, as in what is commonly known as basket work,
shown in Figure 2, and of which two layers may be used, firmly pressed together
with a filling of wood, paper, cloth or other fibrous substance between them. The
strips of wood are not necessarily to be arranged in the manner aforesaid. They
may be laid parallel to each other and cemented or arranged in any other manner
necessary to form a diaphragm which shall be practically continuous although
composed of several parts.
A circular metallic disc a rests upon the diaphragm D opposite the centre of the
opening C. A hole through the centre of this disc admits of the passage of the
conducting line wire b, the end of which is securely wound around a pin c, of
sufficient length to allow its ends to rest on the surface of the disc a and thus
prevent the wire from slipping out, while at the same time the tension of the line
wire presses the disc a firmly against the diaphragm D.
dd, Figures 1 and 2, represent a sound collector, which may be constructed of
wood or other resonant material, Figure 1 showing it in elevation, and Figure 2
giving an end view. A hole through the centre of this sound collector shown by
the dotted lines e e admits of the passage through it of the line wire b, upon which
it moves freely. The base of the sound collector is slightly concaved, so that its
edges alone touch the diaphragm D against which it is pressed by means of the
spiral spring f, one end of which is secured to the line wire b while the other
acts against the point of the sound collector at g, the line wire b passing freely
through the centre of the spiral.
Having now particularly described and ascertained the nature of the said
Invention, as communicated to me and in what manner the same is to be
performed, I declare that what I claim is:
1. In a mechanical telephone, the composite diaphragm, made of thin strips of
wood, woven, folded, cemented, sewed, or otherwise fastened together substantially
as described.

page_text: 2. In a mechanical telephone, the composite diaphragm, made of thin strips of
wood, substantially as described, two layers of which are joined together, with a
filling of wood, cloth, paper, vellum, or any other suitable material, substantially as
described.
3. In a mechanical telephone, the sound collector d consisting of a block of
resonant material mounted upon the line wire and resting against or secured to the
diaphragın, substantially as described.
4. In a mechanical telephone, a composite diaphragm the outer surfaces of which
are of wood, in combination with the sound collector d, substantially as described.
Dated this 24th day of September 1884
WM P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
Agents for the Applicant.
WM P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
Agents for the Applicant.