IMPROVEMENTS IN TELEPHONE TRANSMITTERS
Year: 1884

page_text: ECIFICATION.
I, WILLIAM ROBERT LAKE, of the firm of Haseltine Lake & Co, Patent Agents
Southampton Buildings, in the County of Middlesex do hereby declare the nature
of my invention for "IMPROVEMENTS IN TELEPHONE TRANSMITTERS
to be as
follows:-
This invention relates to telephone transmitters, and comprises a spring-point
which has a continuous bearing on the inside of the diaphragm and connects with,
and disconnects from, another spring by means of which the connections are made
and broken instead of the connections being made and broken by the point on the
diaphragm.
In this respect the improved transmitters differ essentially from other transmitters
by the fact that in the improved device the sound is produced at the opening of
the current; whilst ordinarily the sound is produced at the closing of the current.
The transmitting wire is attached to the spring carrying the point, and the
battery wire to the intermediate spring; as will be hereinafter fully described.
In carrying the said invention into practise I provide a suitable case which
protects and supports the mechanism.
The diaphragm is held in position by an India-rubber lined clamp securely
attached to the door of the case. A frame is also attached to the said door and
supports, by means of brackets, a spring supporting a platinum point. A second
spring is supported by a stud which is attached to the door of the case.
Set screws
are employed to adjust the springs to have a proper movement in connection with
each other and the diaphragin.
Buttons are respectively attached to the inner faces of the inner ends of the
springs, and they are faced with any suitable conducting substance, but preferably
carbon. Attached to the back of one button and projecting through the carbon
and to the diaphragm, is a pin or point which is made of suitable conducting
material with a platinum point, or wholly of platinum. The other button has a
hole through it for the said pin freely to pass. To the outer edge of the latter
button is attached a platinum point which is employed to make and break the
connections between the carbon buttons. The wire leading to the receiving
D

page_text: instruments is attached by ordinary means to the first spring and the battery wire
is attached to the second spring.
The diaphragm is made of the ordinary metal, that is to say, it is a thin metal
disc, preferably of soft iron.
The device is operated by vibrations produced by the human voice close to the
diaphragm.
The advantages of this construction are that sound is transmitted much more
distinctly than heretofore and with a much greater plenitude, and at the same
time there is a freedom from counter or false vibrations of the diaphragm and so
far as experiments have been conducted, there is no disturbance by induction or a
loss of plenitude thereby.
The improved instrument is particularly advantageous for transmitting long-
distance-messages.

page_text: COMPLETE SPECIFICATION.
"
I WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake, and Co, Patent Agents,
Southampton Buildings, in the County of Middlesex, do hereby declare the nature
of my invention for ." IMPROVEMENTS IN TELEPHONE TRANSMITTERS and in what
manner the saine is to be performed, to be particularly described and ascertained in
and by the following statement:—
.
This invention relates to telephone transmitters and comprises a spring point
which has a continuous bearing on the inside of the diaphragm and connects with,
and disconnects from, another spring by means of which the connections are made
and broken, instead of the connections being made and broken by the point on the
diaphragm.
In this respect the improved transmitter differs essentially from other trans-
mitters by reason of the fact that in the improved device the sound is produced at
the opening of the current, whilst ordinarily the sound is produced at the closing
of the current.
The transmitting or line wire is attached to the spring carrying the point, and
the battery wire to the intermediate spring; as will be hereinafter fully described.
In the accompanying drawing,
Figure 1 is a central sectional view of a telephone transmitter constructed
according to this invention.
Figure 2 is a section on the line Z Figure 1, looking in the direction indicated by
the arrow .
A represents a portion of the case which protects the mechanism, its form and
the material of which it is composed being non-essential provided it furnishes &
suitable support for the mechanism.
O represents the diaphragm which is held in position by an india-rubber lined
clamp II securely attached to the door B. A frame G is also attached to the said
door, and supports, by means of brackets e, f, the spring D carrying the platinum
point D¹.
The spring E is supported by a stud H which is attached to the door B of the
case A.
Set-screws g, h, are employed to adjust the springs D E to have a proper
movement in relation to each other and the diaphragm.
Buttons c, d are respectively attached to the opposing faces of the inner ends of
the springs D, E, and they are faced with a suitable conducting substance, preferably
carbon.
Attached to the back of the button c, and projecting through the carbon and to
the diaphragm C, is a pin or point D' which is made of suitable conducting
material with a platinum point, or wholly of platinum. The button & has a hole
through it for the pin D' freely to pass. To the outer edge of the button d is
attached a platinum point E¹ which is employed to make and break the contact
between the carbon buttons c, d. The wire K leading to the receiving instrument
is attached by ordinary means to the spring D, and the battery wire L is attached
to the spring E. The diaphragm C is made of ordinary material, that is to say, it
is a thin metal disc preferably of soft iron.

page_text: The device is operated by vibrations produced by the human voice close to the
diaphragm.
The advantages of this construction are that sound is transmitted much more
distinctly than heretofore and with a much greater plenitude, and at the same time
there is a freedom from counter or false vibrations of the diaphragm, and so far as
experiments have been conducted, there is no disturbance by induction or a loss of
plenitude thereby.
The improved instrument is particularly advantageous for transmitting long-
distance messages.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
In a telephone transmitter, the spring D carrying the point D¹, in combination
with the intermediate spring E carrying the point E, the diaphragm C, and the
wires K L, substantially as, and for the purpose herein specified.
Dated this 14th day of February 1885.
HASELTINE, LAKE & Co.,
For the Applicant.
HASELTINE, LAKE & Co.,
For the Applicant.