Improvements in Mechanical Telephones.
Year: 1890

page_text: COMPLETE SPECIFICATION.
[Communicated from abroad by MAROUS WHITNEY KNIGHT, of 9, Jefferson Street,
Milford, Massachusetts, United States of America, Physician.]
Improvements in Mechanical Telephones.
I HENRY HARRIS LAKE, of the firm of Haseltine Lake & Co. Patent Agents,
Southampton Buildings in the County of Middlesex, 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 :-
My invention relates especially to transmitters for mechanical telephones, and it
consists in certain novel features as hereinafter fully set forth, the object being to
produce a similar, cheaper and more effective device of this character than is now in
ordinary use.
In the accompanying drawing
Figure 1 is a front elevation of my improved transmitter, Figure 2 a vertical section
taken on line in Figure 1, and Figure 3 an elevation of the diaphragm, the body
or mouth piece being removed.
Like letters and figures of reference indicate corresponding parts in the different
figures of the drawing.
The nature and operation of the improvement will be readily understood by all con-
versant with such matters from the following explanation.
In the drawings A represents the back plate, and B the case or body. The back
plate is constructed of wood and is provided with a wire opening. b. The case R is
cylindrical in cross-section and is constructed of glass. An annular flange d is formed
around one end of said case or body. The opposite end is bent or curved inward,
forming a circular mouth piece f.
Slots g are formed in the edge of the flange d. Screw bolts h, passing through
said slots into the back plate A, secure said case thereto.
Washers i formed of rubber or similar material, are disposed around the bolts of
both sides of the Hange d.
Four glass lugs & are secured to the face of the plate A equidistant from the wire
opening b, and project within the case B. A cylinder of copper or similar metal
fits closely within the case, one edge thereof engaging the Ings k.
A diaphragm D, composed preferably of thin sheet metal, closes the outer end of
the cylinder C, and is provided centrally with a wire-opening m, in alignment with
the opening in the plate A. The conducting wire H passes through the openings
and a button K is secured to the outer end thereof, sail button projecting into the
mouth of the case.
h
The high tension of the wire H upon said button draws it against the diaphragm
and holds the cylinder C firmly against the lugs k, the sound vibrations entering the
mouth, and transmitted by the diaphragm to the wire are intensified by this construc-
tion. The glass forming the case being in contact with the metallic cylinder to which
said diaphragm is secured is found to greatly augment the sound waves and render
them much sharper and more distinct.
k
The lugs may be formed on the inner face of the body B and integral therewith,
instead of on the back plate, if desired.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
First. In a transmitter for mechanical telephones a back plate, a glass case or body
secured thereto, and a diaphragm secured to a metallic cylinder within said body, said
cylinder being held in engagement with glass lugs on said back plate by the tension
of the conducting wire, substantially as described.

page_text: Second. In a transmitter for mechanical telephones, a glass body or mouth piece
in contact with a metallic cylinder bearing the diaphragm, substantially as doseribed.
Third. In a body or mouth piece for a mechanical telephone a transmitter composed
of glass and adapted to contain the diaphragm, substantially as described.
Fourth. In a transmitter for mechanical telephones a wooden back-plate, a cylin-
drical glass body having an annular attaching flange at one end, its opposite end being
curved inward to form a mouth piece, glass Tugs on the backplate projecting into said
body; a metallic cylinder and a diaphragm secured to one end thereof, all being
arranged substantially as described.
Fifth. In a transmitter for mechanical telephones, a cylindrical glass body provided
with a mouth piece and secured to a wooden lack plate; flexible washers interposed
botwoen said body and plate; a metallic cylinder disposed within the body in ougage-
ment therewith; a diaphragin closing one end of said cylinder; a button secured
to a conducting wire passing through the diaphragm and back plate; and glass lngs
on said plate in engagement with the opposite end of said cylinder, substantially as
described.
Sixth. A transmitter for mechanical telophones, comprising a cylindrical glass body,
a metallic cylinder within the bo ly in engagement therewith, and a metallic diaphragin
closing one end of said cylinder, its opposite ends resting on glass lngs within said
body, substantially as described.
Seventh. In a device of the charactor described the combination with the woolen
back plate A of the glass body B, the metallic cylinder C. provided with the
diaphragm D and the glass lugs k, arranged substantially as described.
Eighth. In a mechanical telephone, the plate A provided with the opening band
glass lugs k, in combination with the glass Lody B, secured to said plate, and having
the mouth and flange d, the metallic cylinder (provided with the diaphragan 1,
having the opening m, the button K and wire 11, and the flexible washers i interposed
between said body and plate, substantially as described.
D c.l
HASELTINE, LAKE & Co.,
45. Southampton Buildings, London, W., Agents for the Applicant.