IMPROVEMENTS IN "TELEPHONE TRANSMITTERS
Year: 1885

page_text: COMPLETE SPECIFICATION.
I J.ENSIGN FULLER of Chicago in the County of Cook and State of Illinois
one of the United States of America, Electrician do hereby declare the nature of
my invention for IMPROVEMENTS IN "TELEPHONE TRANSMITTERS" and in what
manner the same is to be performed to be particularly described and ascertained in
and by the following statement:-
Fig, 1 is a view in perspective of the invention as adjusted upon the inside door
of the transmitter.
Fig, 2 is a vertical sectional view thereof through line x-x¹ of Fig 3.
Fig, 3 is a plan view of the instrument.
Figs, 4, 5, 6 and 7 represent modifications of the devices for regulating the
position of the electrodes; figure 4 showing two adjusting-nuts one above the bar C
and the other below to act as a lock-nut; figure 5 showing the threaded screw
passing through the metal bar C with no insulating ring around said screw but
showing the insulated end to lever F, and figure 6 showing the nut in passing
through the insulating ring, figure 7 shows flattened extension of lever F with
adjusting devices.
A is the door of the transmitter.
a the orifice through which the sound waves reach the diaphragm. B is the
diaphragm bis a soft rubber ring surrounding the periphery of the diaphragm
61 62 are springs which hold the diaphragm in position. D is a metallic base.
which supports lugs 1, .e is the wire leading from hinge K. to base D. c¹ is the
wire leading from post h to hinge K¹,
The transmitter is connected with one pole of the battery by wire ell to hinge K
the circuit being from hinge K to base D thence through trunnion t lever F and
platinum point p¹ to the carbon button & from said button over bar C to post h
thence by wire e¹ to hinge K¹ and to the battery.
From post his suspended a solid metallic bar C by a stiff spring c and screws 8 8²,
g is a metallic cup fastened to the bar C by a screw n and holds the carbon
button d
F is an automatic reacting lever composed of metal pivoted at t and supported
at either end by screws f¹f which pass through lugs 7. p is a wire held by
lever F and in constant contact with the diaphragm. p¹ is a platinum point also
held firmly by lever F and in intermittent contact with carbon button d. m¹ is a
Umina 31

page_text: threaded pin to which is attached spring r and hook 1, around which is placed the
adjusting nut m which adjusts the bar C and the lever F thus regulating the
juxtaposition of the two electrodes.
m² is a ring set in the bar C composed of gelatinized fiber or any good
insulating material and through which passes pin m³ thus preventing a short
circuit from lever F to bar C.
The object of the invention is to furnish means by which the limit of variation
in the strength of an electric current is increased or made greater than heretofore.
The invention is applied to an electric current which upon being made vibratory
by the variation of impact between the electrodes is used for the transmission or
reproduction telephonically of speech signals and all kinds of sounds that can be
made to produce vibratory motion in diaphragms The invention is intended to
render such transmission or reproduction more perfect and clear than heretofore.
I do not restrict myself to the exact mechanical arrangement shown to which
I limit my description because the same may be modified in various ways without
imparting new qualities or producing different results.
For instance the entire bar C might be constructed in more than one piece or it
might be made in one piece more susceptible to vibration which should be very
thin at its junction with post h and gradually thickened toward the point where
thumb screw m passes through it. Other changes of form, size or arrangement
might be made which would be obviously mere modifications of the apparatus
described.
In the commercial adaptation for several years of the transmitters now in use it
has many times been my unpleasant experience to find that when speaking too
loudly in order to overcome some cross or fault in the line or because the battery
power was weak or where from other causes the ordinary tones of the voice were
nearly unintelligible to the listener the electrodes were thrown far apart thus
preventing any vocal sound whatever from being transmitted.
To produce a telephone that would absolutely overcome this serious fault has
been my effort and the invention is the result of a long range of careful
experiments for this purpose in that instead of any tendency to throw the
electrodes apart by loud speaking the action of the reacting lever or levers
necessarily causes them to receive a closer pressure by the increased amplitude of
the vibrations of the diaphragm and thus transmit the exact modulations of the
sound waves thrown thereon.
The operation of the apparatus shown herein is as follows:-
Upon speaking into the mouth piece there is given to the diaphragm a forward
and back movement which is increased at the point of contact viz, the platinum
point and the carbon button by means of the lever F and the bar C which being
united by wire r and post m³ constantly and automatically vary the impact at
such point of contact.
These rapid movements forward and back cause vibrations in the current. Thus
as the lever F being pivoted on trunnions & is propelled forward at one end by the
action of a sound wave it is necessarily and simultaneously repelled to an equal
degree at its opposite end and because this opposite end is joined to bar C by
wire r, pin m' an equal and simultaneous depression is caused in bar C throughout
its entire length and with it the carbon button is brought toward the platinum
point and in close contact with it. I am aware that reacting arms or levers
carrying electrodes have been used and I do not claim such arms or levers broadly.
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
1. The combination, with the diaphragm of the approximately equal armed
lever F having one end impinging on the diaphragm and supporting electrode p¹
the lever carrying electrode d and the adjustable connection between an

page_text: intermediate portion of said lever C and the end of lever F opposite that which
carries its electrode substantially as described.
2. The lever C pivoted at one end and carrying electrode d at the other end, the
lever F pivoted at about its middle and supporting at one end electrode p² and the
link connecting the other end of said lever with an intermediate portion of lever C
in combination with the diaphragm. and intermediate mechanism operated thereby
for imparting its direct movement to electrode p¹ all as set forth.