IMPROVEMENTS IN MICROPHONES
Year: 1882

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
county of Middlesex, Gentleman, for an Invention of "IMPROVEMENTS IN
MICROPHONES."-A communication from abroad by Doctor Arsène D'Arsonval,
of Paris, in the republic of France.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents on the 11th May 1882.
כן
JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN MICROPHONES a communication from abroad
by Doctor Arsène D'Arsonval of Paris in the Republic of France
This Invention relates to microphonic transmitters or apparatus and consists of
certain improvements in the construction and arrangement and mode of supporting
this apparatus as hereinafter described. According to this Invention a manganesian
agglomerate or compound containing bioxide of manganese is employed to form the
sensitive part of the apparatus in place of the carbon ordinarily used for this
purpose and the sensitiveness of the apparatus that is to say the pressure exerted by
the moveable part upon the stationary part is regulated or controlled by a magnet
the position of which is capable of being adjusted at will. The influence of weight
in connection with this adjustment being thus dispensed with, the apparatus is
rendered capable of being moved or placed in any convenient position without
affecting its action or working. The apparatus is moreover supported in a peculiar
manner hereinafter described whereby all shocks and vibrations are prevented from
being transmitted to the working parts and the said apparatus is thus enabled to
be employed in workshops mines and other similar places where it is liable to be
exposed to frequent shocks and vibrations.
In carrying out this Invention the microphonic apparatus is provided with a
plate or diaphragm to the back of which are attached two grooved or notched
blocks composed of a manganesian agglomerate containing bioxide of manganese
and forming supports for say two sensitive plates or contacts of manganesian

page_text: agglomerate carrying two metal plates. The extremities of these two sensitive
blocks are bevelled on both sides but at different angles in order that the amplitude
of their vibrations may be different and these bevelled extremities are lodged in
the grooves or notches in the two blocks firstly described which are connected with
a battery or other apparatus by suitable conducting wires.
The pressure of the sensitive plates or contacts upon the microphone plate is
adjusted by means of a magnet which is adjustable to or from the metal plates on
the said blocks.
The advantages of this arrangement are that the apparatus is rendered highly
sensitive and the adjustment of the pressure of the moveable part or contacts upon
the fixed or stationary parts is effected without the influence of weight, so that the
apparatus is capable of working in any position.
The microphone arranged as hereinbefore described is carried by a frame which
is suspended or supported in a peculiar manner as hereinafter described for the
purpose of deadening or entirely absorbing all shocks or vibrations other than those
communicated by the action of the air in speaking.
For this purpose the frame is provided at its base with two hollow rods which
pass freely through openings formed in the lid or cover of a case or hollow base
which may contain an induction coil and which constitute the support of the
whole apparatus. The conducting wires connecting the grooved blocks on the
microphone plate with the battery as herein before described are passed through
these hollow rods. The said rods are provided with shoulders resting upon arms
which are secured to the rods by nuts screwed on the extremities of the latter and
the arms are supported or suspended by helical springs contained in hollow pillars
fixed to the case forming the base of the apparatus. The helical springs are
suspended from screwed rods provided with nuts bearing upon the upper extremities
of the pillars. By these means the microphonic transmitter is protected from the
effects of shocks and vibrations acting in a vertical direction and in order to protect
it from the effects of lateral vibrations or disturbances also the frame is provided
at its upper part with a bracket carrying two hooks attached to the extremities of
two horizontal helical springs connected at their opposite extremities with two
other hooks provided on a cross-bar connecting the upper part of the two hollow
columns herein before described.
The apparatus may be provided with suitable forked rests or supports for flexible
speaking or hearing tubes or independent telephones of ordinary construction and
one of these supports may act as a contact maker and breaker.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Henry Johnson in the Great Seal Patent Office on the
11th November 1882.
JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
3 Gentleman "IMPROVEMENTS IN MICROPHONES a communication from abroad
27
by Doctor Arsène D'Arsonval of Paris in the Republic of France.
This Invention relates to microphonic transmitters or apparatus and consists of
certain improvements in the construction and arrangement and mode of supporting
such apparatus as hereinafter described. According to the said Invention a
manganesian agglomerate or compound containing binoxide or peroxide of
manganese or any other substance of moderate conducting power or carbon may
be employed to form the sensitive part of the apparatus and the sensitiveness of
the apparatus that is to say the pressure exerted by the movable part upon the
stationary part is regulated or controlled by a magnet the position of which is
capable of being adjusted as required. This magnetic adjustinent renders springs
or counterweights unnecessary and the apparatus is rendered capable of being
moved or placed in any convenient position without effecting its action or working.
The apparatus is moreover supported in a peculiar manner hereinafter described
whereby all shocks and vibrations are prevented from being transmitted to the
working parts and the said apparatus is thus enabled to be employed in workshops,
factories mines and other similar places where it is liable to be exposed to frequent
agitation or disturbances,
And in Order that my said Invention may be fully understood I shall now
proceed more particularly to describe the same and for that purpose shall refer to
the several figures on the annexed sheet of drawings the same letters of reference
indicating corresponding parts in all the figures,
Figure 1 of the accompanying drawing is a front elevation partly in section
showing the general arrangement of a microphonic transmitter constructed according
to this Invention
Figure 2 is a side elevation partly in section corresponding to figure 1 and figure 3
is a view of the inner side of the microphone plate.
According to the arrangement illustrated in the drawing the improved
microphonic apparatus is provided with a plate or diaphragm A to the back of
which are attached two grooved or notched blocks a, a', composed of a manganesian
agglomerate containing binoxide or peroxide of manganese or composed of carbon
or any other material of moderate conducting power whose capacity as a
conductor varies proportionately to the pressure to which it is subjected such as
metallic sulphides metallic powders oxides or oxysulphides and the like. These
blocks form supports for two sensitive plates or contacts B, B', of manganesian
agglomerate or of any of the above mentioned substances of carrying two metal
plates b, b, As shown in Figure 2 the extremities of the two sensitive plates B, B',
are bevelled on both sides but at different angles in order that the amplitude of
their vibrations may be different and these bevelled extremities are lodged in the
grooves or notches a a³ in the two blocks a, a', which are connected with a battery
or other apparatus by suitable conducting wires x, y,
The pressure of the sensitive plates or contacts B, B¹, upon the microphone plate
or diaphragm A is regulated by the attraction of a magnet C which is adjustable
to or from the metal plates b, b¹, by means of a screw c.
The advantages of this arrangement are that the apparatus is rendered highly
sensitive and the adjustment of the pressure of the movable part or plate A is
rendered independent of the influence of gravity so that the apparatus is capable of
working in any position although in the example illustrated in the drawing the
pparatus is represented in a vertical position
The improved microphone arranged as hereinbefore described is carried by a

page_text: frame D which is suspended or supported in a peculiar manner for the purpose
of deadening or entirely absorbing all shocks or vibrations other than those
communicated by the action of the air in speaking.
For this purpose the frame D is provided at its base with two hollow rods D', D',
which pass freely through openings d, d', formed in the lid or cover of a case or
hollow base H supporting the apparatus and the conducting wires x y connecting
the grooved blocks a, a, with the battery as hereinbefore described are passed
through these hollow rods D¹ D', The said rods are provided with shoulders d² d³
resting upon arms E E' which are secured to the rods by nuts e e¹ and the arms E, E¹,
are supported or suspended by helical springs F, F', contained in hollow pillars G G'
fixed to the base H, The helical springs F F' are suspended from screwed rods ƒ ƒ¹
provided with nuts f2 bearing upon the upper extremities of the pillars G G¹ By
these means the microphone transmitter is protected from the effects of shocks and
vibrations acting in a vertical direction and in order to protect it from the effects
of lateral vibration or disturbance also the frame D is provided at its upper part
with a bracket I carrying two hooks attached to the extremities of two
horizontal helical springs JJ' connected at their upper extremities with two other
hooks on a cross bar K connecting the upper part of the two hollow columns G G¹
herein before described. It is evident that the microphone transmitter thus
suspended is effectually protected from the effects of shocks vibrations and similar
disturbances in all directions and is thus rendered capable of working efficiently in
situations where its supports are subject to movement or vibration.
The apparatus may be provided with the usual rests or supports L L¹ Figure 1
for flexible speaking or hearing tubes not shewn in the drawing and one of such
supports (L' for example) may act as a contact maker and breaker in the usual
manner.
The apparatus as shown in the Drawing is arranged for standing upon a table
and the support L is affixed to the case or base H which may also contain the
induction coil as shown at M.
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters patent is
First. In microphonic transmitters the substitution of magnetic attraction for
springs or weights for regulating the contacts substantially as and for the purpose
hereinbefore described.
Second. In microphonic transmitters the combination of the plates B B¹ carrying
the metal plates bb with the adjustable magnet C substantially as and for the
purpose hereinbefore described with reference to the accompanying Drawings.
Third. The mode of suspending Microphonic transmitters substantially as and
for the purpose hereinbefore described with reference to the accompanying
Drawings.
Fourth. The general arrangement and combination of parts constituting the
improved instrument or apparatus substantially as herein before described and
illustrated in the accompanying Drawings.
In witness whereof I the said John Henry Johnson have to this my
Specification set my hand and seal this first day of August One thousand
h hundred and sighty two.
J. HENRY JOHNSON (L.s.)