Improvements in Microphones.
Year: 1892

page_text: Date of Application, 11th Oct., 1892
Complete Specification Left, 11th July, 1893-Accepted, 12th Aug.,
1893
PROVISIONAL SPECIFICATION.
[Communicated from abroad by ELOY NORIEGA, of Mexico, in the Republic of
Mexico.]
Improvements in Microphones.
I, HENRY HARRIS LAKE, of the Firm of Haseltine Lake & Co., Patent
Agents, 45 Southampton Buildings in the County of Middlesex, do hereby declare
the nature of this invention to be as follows:-
The object of my invention is to provide a simple and efficient microphone for
the transmission of articulate speech, in which delicate adjustments will be avoided
and which will not be affected by the changing of temperature or atmospheric
conditions.
My invention consists in a diaphragm of wood or analogous material, with the
edges bound with elastic rubber binding, perforated carbon blocks secured to the
diaphragm, carbon cylinders inserted in the perforations of the blocks, a pressure
spring for holding the cylinders against the sides of the apertures in the blocks,
and a body of fibrous absorbent material interposed between the spring and the
carbon cylinders, all as will be hereinafter more fully described.
.
The diaphragm is preferably made of wood, and its edges are enclosed in an
elastic rubber binding and the said diaphragm is enclosed in a metallic frame,
attached to the door of the transmitter box. In the door is formed an aperture,
through which sounds pass to the diaphragm.
To the diaphragm are secured perforated carbon blocks in the apertures of
which are inserted the tenons of the carbon cylinders. One of the circuit wires is
connected with one of the carbon blocks and the other circuit wire with the other
carbon block. To the back of the diaphragm-cell are attached studs provided with
adjusting nuts which are grooved circumferentially to receive the forked ends of
the spring. To this spring is attached a cup, in which is inserted a body of elastic
absorbent fibrous material, which presses against the carbon cylinders and serves as
a damper to control the vibrations of the cylinders, also to absorb moisture from
the cylinders and the air in their vicinity. The pressure of the fibrous material is
varied by turning the nuts.
The varying of the conductivity of the instrument produces electrical pulsations
in the primary telephone circuit, which induces currents in the secondary wire of
the induction coil of the line-circuit which entering the receiving telephone,
represent the sounds uttered against the diaphragm.
Dated this 11th day of October 1892.
HASELTINE, LAKE & Co.,_.
45, Southampton Buildings, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Microphones.
1, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent
Agents, 4 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 :--
The object of my invention is to provide a simple and efficient microphone for
the transmission of articulate speech, in which delicate adjustments will be avoided
and which will not be affected by change of temperature or atmospheric conditions.

page_text: My invention consists in a diaphragm of wood or analogous material, with the
edges bound with elastic rubber binding, perforated carbon blocks secured to the
diaphragm, carbon cylinders inserted in the perforations of the blocks, a pressure
spring for holding the cylinders against the sides of the apertures in the blocks, and
a body of fibrous absorbent material interposed between the spring and the carbon
cylinders, all as will be hereinafter more fully described.
In the accompanying drawing,
Figure 1 is a rear elevation of my improved microphone, and
Figure 2 is a vertical transverse section taken on line ax of Figure 1.
Similar letters of reference indicate corresponding parts in both views.
According to this invention the diaphragm A is preferably made of wood, and
its edges are enclosed in an elastic rubber binding a, and the said diaphragm is
enclosed in a metallic frame b, attached to the door c of the transmitter box d. In
the door e is formed the aperture B, through which sounds pass to the diaphragm A.
To the diaphragm A are secured perforated carbon blocks C C1, in the apertures
of which are inserted the tenons of carbon cylinders D. One of the circuit-wires
is connected with the carbon block C and the other with the carbon block C¹. To
the back of the diaphragm-cell are attached studs e e¹, provided with adjusting
nuts ff, which are grooved circumferentially to receive the forked ends of the
spring 9. To the spring g is attached a cup h, in which is inserted a body i of
elastic absorbent fibrous material, which presses against the carbon cylinders D and
serves as a damper to control the vibrations of the cylinders; also to absorb
moisture from the cylinders and the air in their vicinity. The pressure of the
fibrous material is varied by turning the nuts fƒ¹.
The varying of the conductivity of the instrument produces electrical pulsations
in the primary telephone circuit, which induces currents in the secondary wire of
the induction coil of the line-circuit, which entering the receiving telephone,
represent the sounds uttered against the diaphragm A.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-
:-
In a microphone, the combination of the diaphragm A, formed of wood or
analogous material, the perforated carbon block C C', attached to the diaphragm,
the carbon cylinders D, having their ends inserted in the perforated carbon blocks,
the adjusting spring g, the cup h, attached to the spring, and a body i, of fibrous
material, inserted in the cup h and bearing against the carbon cylinder D,
substantially as specified.
Dated this 11th day of July 1893
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.