Improvement in Telephone Transmitters.
Year: 1896

page_text: Date claimed for Patent under Sect. 103 of Act,
being date of first Foreign Application (in 25th Mar., 1896
United States of America),
Date of Application (in United Kingdom), 24th Oct., 1896
Complete Specification Left, 24th Oct., 1896-Accepted, 20th Mar., 1897
Date of Application (in United Kingdom), 24th Oct., 1896
Complete Specification Left, 24th Oct., 1896-Accepted, 20th Mar.. 1897
Improvement in Telephone Transmitters.
I, WILLIAM ANDREW MOORE, Electrician, of 229 Union Street, Brooklyn, in
the County of Kings and State of New York, United States of America, 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 invention relates to telephone transmitters; and it consists in the devices
and combinations of devices set forth in this specification and the drawings forming
part of the same, in which:
Figure 1 is a central vertical sectional view through an apparatus embodying
my invention; and Fig. 2 is a cross-sectional view on line x, Fig. 1, the
comminuted conducting material having been removed to more clearly exhibit
the other parts.
C is the case, the forward portion coming to a suitable size to hold the mouth-
piece M, and within the case (which is preferably circular in form) there is a
shoulder S. Against this shoulder rests the first diaphragm D, which I prefer to
make of oiled silk. At a very slight distance therefrom, measured by a ring of any
suitable substance, interposed between, 1 place the second diaphragm D¹, both
being held in place by yoke springs 8, secured to the side of the case and bearing
upon the second diaphragm. This second diaphragm I also provide with a series
of projections p, on the side farthest from the mouthpiece, and at the centre on the
opposite side 1 put a button b, of such size that it will rest against the first
diaphragm D. This button, however, might be secured to the first diaphragm and
rest against the second, although I prefer the arrangement shown. The projection p
I prefer to arrange within the periphery of a circle concentric with the center of
the diaphragm and extending over a comparatively small portion of its surface,
Bay about one-third its diameter. The rear portion of the case I prefer to fit to
the other part by providing each with suitable screw-threads, as shown in Fig. 1.
To the rear part 1 secure a block B, preferably of non-conducting material.
On the side nearest the diaphragm this block is provided with a circular recess R,
the cross-area of which substantially corresponds in size to or a little exceeds
the area of the surface covered by the projections p. This block is also provided
on the same face with a groove or a rabbet g, in which I seat a ring of
non-conducting material, preferably felt, which bears lightly against the
diaphragm D. The degree of pressure, as is manifest, may be easily regulated by
turning the rear part of the case farther on or off the sides of the case by means
of the screw-threads already named. In the recess R, I place a solid carbon C',
usually corresponding in size with the width of the recess, but preferably not so
thick as the depth of the recess. Its face is channeled, as shown, and it is also

page_text: provided with a series of small recesses r, one, r³, being preferably arranged in the
center. In this center recess I place a screw ', which extends through the carbon
and into rod of conducting material, thereby securing the carbon to said
rod. In the recess r¹ and over the screw I seat a small piece of non-conducting
material f', to prevent short-circuiting. About the rod I place a tube of
insulating material i, and about it a tube of brass or other suitable material t, the
other face of which for some distance intermediate its ends is screw-threaded, as
shown, the other end being preferably squared to receive a thumb-piece T.
Rising from the rear face of the case or secured to it is a boss B. It has two
steps, the first, a circular one, over which may be passed the suspending bracket B².
The next step is screw-threaded, and on it I place a nut N, the thumb-piece T
being placed on the tube t and secured after the nut N has been turned to place.
It will thus be seen that the bracket B2 is held between the step on the boss and
the nut N, so that the instrument is suspended. At the same time it may
readily be turned about in the aperture in said bracket B', as may be desired. It
is also manifest that by holding the case fixed, and turning the thumb-piece T the
carbon C¹ may be advanced toward or withdrawn from the diaphragm D¹ for
adjustment independently of any adjustment of the block B. A set-screw S¹ may
be seated in the boss B for holding to tube t and thereby the carbon C¹ in its
suitably-adjusted position. One circuit-wire w leads from the diaphragm D¹ to
and through the case and to a binding-screw 2, or it may lead to the case, and
that being made of conducting material may be otherwise conducted to its binding-
screw. Another conducting-wire w' leads from the screw s³, set in the rod, to
the second binding-screw st. The whole is preferably mounted in a box B³, the
case being inserted through a circular hole in its face and the bracket B, secured
to the inner side of said box, that side being preferably arranged as a door.
Between the diaphragm D¹ and the solid carbon C, I place a quantity of
finely-divided conducting material, such as powdered carbon, and the purpose of
the recesses in the face of said carbon is that in filling in the powdered material
it may enter in these recesses, and therefore when the device is turned up on its
side, by falling out of said recesses into the space between the face of the sclid
carbon and the diaphragm D', it will furnish a sufficient quantity to well fill said
space without requiring such care and exactness in filling before adjustment, and
yet will leave the powdered material somewhat loose that it may not pack between
the parts.
The use of the two diaphragms with the button between enables me to secure
more powerful vibrations than would otherwise be the case, for as I use and must
use some material placed between the block B and the diaphragm D' (here the felt
ring) to complete the inclosure of the space to be occupied by the fiuely-divided
material, the vibrations of that diaphragm D', if it were itself exposed to the
immediate action of the sound-waves would be somewhat deadened, but by placing
the first diaphragm D in front of that I preserve the full action of a diaphragm of
that size, and communicate the full effect of its vibrations directly to the center of
the second diaphragm (the place where that will have most effect) through the
medium of the button b.
Í have heretofore wrapped the piece of felt about the solid carbon, with its edge
arranged to bear upon the diaphragm similar to diaphragm D¹; but this I find
objectionable in that when adjusting the solid carbon the felt is also moved to or
from the diaphragm, and may therefore press too lightly or too strongly upon it
when the carbon has been properly adjusted. The arrangement now shown
enables me to adjust each independently, and thereby secure exactly such results
as I seek.
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:
1. In a telephone-transmitter the combination of a recessed block, a diaphragm

page_text: whose rim is supported independently of said block, and an annulus of soft non-
conducting material whose interior diameter is greater than the diameter of the
iuclosed solid carbon interposed between the two and completing the inclosure of a
space bounded by the diaphragm, the walls of the recess in the block and the
annulus, a solid carbon seated in said recess in the block and a quantity of finely-
divided conducting material interposed between the face of the solid carbon and the
interior face of the diaphragm substantially as set forth.
2. In a telephone-transmitter the combination of a recessed block, a diaphragm
whose rim is supported independently of said block, and an annulus of soft non-
conducting material whose interior diameter, is greater than the diameter of the
inclosed solid oarbon interposed between the two and completing the inclosure of a
space bounded by the diaphragm, the walls of the recess in the block and the
annulus, a solid carbon provided with recesses extending inwardly from its interior
face seated in said recess in the block and a quantity of finely-divided conducting
material interposed between the face of the solid carbon and the interior face of
the diaphragm substantially as set forth.
3. The combination in a telephone of a recessed block the side walls of which
recess extend laterally beyond the line of the projections on the diaphragm, a
diaphragm whose rim is supported independently of said block and provided on its
inner face with a series of projections, a ring of soft non-conducting material whose
interior diameter is greater than the diameter of the inclosed solid carbon placed
intermediate the block and the diaphragm, a solid carbon seated in the recess in
the block and a quantity of finely-divided conducting material interposed between
the projections on the diaphragm and the face of the solid carbon within the space
inclosed by the diaphragm, the block and the ring.
4. In a telephone-transmitter the combination of a diaphragm, a recessed block
set opposite said diaphragm a ring of soft non-conducting material intermediate the
diaphragm and the block and surrounding the recess therein, a solid carbon placed
in the recess, a quantity of finely-divided conducting material placed intermediate
the diaphragm and the carbon and means substantially as described for
independently adjusting the position of the block and the position of the carbon
with relation to the diaphragm.
5. The combination of a telephone-transmitter of a case an oiled-silk diaphragm
supported at its rim within said case and opposite the mouthpiece, a second
diaphragm supported within the case beyond the first and held in position by
springs secured to the case, a button located at the center of the second diaphragm
and making contact with the first, a series of projections extending inwardly from
the second diaphragm, a recessed block secured to the rear face of the case, which
said face is screw-threaded to the sides of the case, a ring of soft non-conducting
material placed intermediate the second diaphragm and the block, a solid carbon
placed in the recess in said block and supported on a tube extending through a
screw-threaded boss on the rear face of the case, a conducting-rod extending from
the solid carbon through the tube, from which it is insulated, to a suitable
connection, a bracket with a circular aperture in which the boss of the case is
seated, a nut placed upon said boss but beyond the bracket, a thumb-piece secured
to the tube but beyond the nut a connection leading from the diaphragm, a series
of recesses extending inwardly from the face of the solid carbon and a quantity of
finely-divided conducting material interposed between the diaphragm and the solid
carbon all combined substantially as set forth.
Dated at New York City NY IISA October 13th 1806
WILLIAM ANDREW MOORE.