IMPROVEMENTS IN TELEPHONES
Year: 1882

page_text: LETTERS PATENT to John Henry Johnson of 47 Lincolns Inn Fields in
the County of Middlesex Gentleman for an Invention of "IMPROVEMENTS
IN TELEPHONES A communication to him from abroad by Léon de Locht-
Labye of Paris in the Republic of France.
"
PROVISIONAL SPECIFICATION left by the said John Henry Jolinson at the
Office of the Commissioners of Patents on the 11th October 1882.
JOHN HENRY JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN TELEPHONES" a communication to me from
abroad by Léon de Locht-Labye of Paris in the Republic of France
This Invention relates to improvements in Telephones and it consists in the
employment for the purpose of communicating vibrations to a resisting body or
diaphragm of a lever connected to an armature suspended before the poles of a
magnet or electro-magnet as hereinafter described The lever may be formed in
one with the vibrating body or diaphragm or may be provided with a hammer in
contact with the said diaphragm. The oscillations of the lever and the action of
the hammer on the surface opposed to it synchronise with or correspond to the
movements of the armature when the latter is acted on by Telephonic currents from
a distant station circulating in the coils of the magnet and in like manner when
the Telephone is employed as a Transmitter the vibrations of the diaphragm
produce through the lever corresponding vibrations of the armature suspended
before the poles of the magnet.and like undulations in the current The fulcrum or
axis of oscillation of the lever may be situated either between or beyond the points
at which the magnetic attraction or repulsion of the armature and the reaction of
the vibrating body or diaphragm are applied.
It is found that articulate sounds are more clearly and distinctly transmitted
when the hammer and diaphragm are composed of non resonant materials such as
cork, india rubber ebonite, mica, and the like but other materials may however be
employed if found desirable.
The distance between the armature and poles of the magnet is adjusted in such
a manner that the maximum of magnetic effect may be produced-This adjustment

page_text: may be effected by means of a screw with a moveable nut which serves to shit the
fulcrum of the lever or by altering the position of the poles of the magnet relatively
to the armature or by moving the diaphragm.
In carrying out this Invention a horse shoe magnet is employed the said magnet
being provided at each pole with soft iron prolongations or extensions carrying
coils of insulated copper wire The extremities of this wire are connected to
terminals communicating with the conducting wires In proximity to the poles of
this magnet is an armature of soft iron or magnetized steel the poles of the armature
being in this latter case arranged opposite the contrary poles of the magnet and
being of considerable thickness The armature is also in the form of a horeshoe and
is capable of oscillating on centres or pivots being rigidly connected to an arm or
lever bent outwards at one end and terminating in a small cap or hammer of cork,
rubber, wood or inetal. This Cap or hammer bears against a thick rigid plate (say
of Cork) acting as a diaphragm and retained in position by the mouthpiece of
the Telephone which may be provided with a sounding box underneath the
diaphragm.
The axis on which the armature and lever oscillate is carried by a brass bracket
or support which is capable of being moved upwards or downwards by means of a
sleeve with a moveable nut supporting the bracket. This sleeve slides in a rigid
support carried by pillars projecting from the base of the apparatus and provided
with nuts so as to enable the said support to be, fixed at the required distance.
A scrow working in the nut on the sleeve serves to draw up the sleeve and thus
adjust the armature at the required distance from the poles of the Magnet.

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
2nd April 1883.
JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN TELEPHONES" a communication to me from
abroad by Léon de Locht-Labye of Paris in the Republic of France
This Invention relates to improvements in Telephones and it is characterised by
the combination with a permanent magnet or electro-magnet, provided at one or at
both its poles with an induction coil of insulated wire; of a rigid armature of steel
or soft iron freely oscillating around an axis and ending in a hammer which bears
on a rigid obstacle, hereinafter referred to also as the "shocked body" or "shocked
piece."
The coils of the bobbin or bobbins on the magnet is or are interpolated in the
telephonic circuit.
The telephonic currents circulating in the bobbins cause the armature to be
alternately attracted and repelled. By reason of the reaction of the rigid obstacle
against which the armature lever rests the repulsion alone is effective in producing
the first movement of the armature. The latter in moving away from the pole
momentarily separates the hammer at the end of the lever from the buttress or rigid
obstacle. This repulsion is succeeded by the attraction of the armature caused by
the following current and the armature is then pulled back to its original position
and tends to pass beyond this position by reason of the attraction and its own vis
viva or momentum, but is stopped in this direction by the rigid piece or obstacle
against which the hammer strikes. The intensity of the blow or shock consequently
results from the combined effect of these two actions and is in direct ratio to the
electro magnetic forces which produce the repulsion and attraction of the armature
The number of shocks is equal to the number of electrical changes produced in the
telephonic circuit.
The sounds or words transmitted by means of this apparatus are reproduced in all
the component vibrations and the telephonić transmission is clear and distinct The
alternative movements of the armature resulting from the action on the magnet
of the telephonic currents circulating in the bobbins produce corresponding
oscillations of the lever and synchronous blows of the haminer upon the rigid
obstacle and inversely when the instrument is employed as, a transmitter the
functions of the apparatus being reversible the emission of sounds or words upon
the rigid obstacle produces synchronous blows upon the hammer and by the inter-
vention of the lever causes corresponding oscillations of the armature before the
magnetic poles. These oscillations of the armature generate in the bobbins electric
currents which can be transmitted to a distant Station.
The lever employed may be of the first second or third order that is to say it's
fulcrum or axis of oscillation may be situated either between or beyond the points
at which the magnetic attraction or repulsion of the armature and the reaction of
the rigid obstacle are applied. The relative lengths of the lever arms and their
actual dimensions vary according to circumstances.
Words are found to be transmitted with more clearness and distinctness when
the rigid obstacle or the hammer or both are composed of dead or non-resonant
materials that is to say materials exempt from molecular vibrations but other
materials. may be employed if found desirable The shocked piece is preferablý
composed of cork India rubber, ebonite wood or other analogous material and is

page_text: of such thickness as to render it rigid and not liable to bend or yield under the
pressure of the armature lever The same effect may be obtained by cementing
or otherwise applying to the rigid obstacle at the shocked point" (namely
the point where the hammer strikes) a small thin soft piece of leather cork or
the like.
E
The armature should be suspended as near as possible to the pole or poles of the
magnet without absolutely coming in actual contact with the latter in order that
the maximum of magnetic effect may be produced The position of the armature
may be adjusted by means of a screw with a moveable nut which serves to shift
the fulcrum of the lever or by altering the position of the poles of the magnet 1
relatively to the armature by analogous means or by moving the "shocked body
or by screwing or unscrewing the hammer upon the lever so as to adjust its
position thereon.
"
It is not necessary to enclose the parts in a case acting as a sounding box as the
"shocked body" may be brought directly in contact with the ear by a suitable 1
mouthpiece or ear pieco By thus dispensing with the sounding box objectionable
reverberations and echoes which are common to many telephones are obviated.
And in order that the 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 2
indicating corresponding parts in all the correspondings figures,
Figure 1 of the accompanying Drawings is a plan of a Telephone constructed
according to this Invention and figure 2 is a longitudinal section of the same the
section being taken along the line 1. 2 figure 1.
A is a horse-shoe magnet provided at its two poles N. S with soft iron pro- 2
longations or extensions carrying coils or bobbins B of insulated copper wire.
The extremities of the wire are connected to terminals K. O. communicating with
the conducting wires. In close proximity to the poles of this magnet A is
suspended an armature C of soft iron or magnetised steel. In the latter case
the poles ns of the armature are arranged opposite the contrary poles S. N. of the
magnet.
The armature is also in a form, the equivalent of a horseshoo and is capable of
oscillating on centres or pivots a a formed by cylindrical pins t t which enter
corresponding cavities drilled in the sides of the armature.
The armature is connected to a rigid lever L of brass bent at a right angle at 3
one end as sliewn and terminating in a small cap or hammer M of cork rubber
wood or metal. This cap or hammer M bears against a thick plate P. of cork, the
said plate being retained in position at its edges by a cover T forming the mouth-
piece or ear piece of the telephone which may be provided with a sounding box F.
The said plate P is what I term the "shocked body" or "shocked piece."
The axis a on which the armature and lever oscillate is carried by a brass
bracket or support which is capable of being adjusted by means of a sleeve G with
a moveable nut supporting the bracket. This sleeve G slides in a rigid support H
carried by pillars D projecting from the base of the apparatus and provided with
nuts Ewhich enable the support H to be fixed at the required distance. A screw V
working in the nut on the sleeve G serves to adjust the arniature at the required
distance from the poles of the magnet.
According to the arrangement illustrated in figures 3. 4 and 5 the sounding box
is dispensed with.
Figure 3 is a front view or plan showing the exterior of the apparatus and
figure is a view shewing the parts at the underside or rear of the "shocked
body." Figure 5 is a vertical section taken along the line 3. 4 figure 4.
The magnet, A is so formed that its poles are situated at different distances from
the centre upon the same diametrical line as shewn at N and S Figures 4 and 5.
The pole N is provided with a pillar R of soft iron the extremity of which is
forked to receive an armature lever m which oscillates on a pin o passed through

page_text: the two legs of the fork. The pole S of the magnet carries a coil or bobbin B
of insulated copper wire upon a cylinder f of soft iron fixed to the said pole.
The armature lever m consisting of a small piece of sheet iron suspended
edgewise so as to present the requisite stiffness or rigidity oscillates on the axis o
and presents at n the same magnetic polarity as the pole N of the magnet
upon which it oscillates and is consequently powerfully attracted by the pole S
of the said magnet
A small metallic hammer m¹ is screwed to the extremity of the armature lever
so as to admit of the adjustment of the distance between the tail of the said
armature lever and the pole S.
The "shocked body "C is composed of a circular piece of wood having a spherical
hollow P formed in its front side and acting as a mouth piece or ear-piece This
piece of wood is connected by pillars c of the same material or of metal to the base
plate X.which carries the magnet and bobbin.
This arrangement simplifies the construction of the apparatus and enables the
sounding box to be dispensed with the rigid "shocked body" being entirely free.
Another arrangement is illustrated in Figures 6 and 7 which represent side views
of the apparatus taken at right angles to each other.
The magnet A is fixed directly to the edge of the piece of wood C and the
pole N which carries the axis of oscillation of the armature is likewise directly
connected to this piece.
The magnet is bent outwards at the extremity connected to the coil so as to
form a sufficient space between the extremity and the "shocked piece" to receive
the cylinder of soft iron that carries the bobbin or coil B. and to allow sufficient
play to the end n of the armature lever.
The shocked body "thus receives at two adjacent points the vibrations trans-
mitted through the hammer at the end of the armature lever and through the axis
of the lever at its point of support or oscillation which is directly connected to
the rigid piece and the sound transmitted to the ear being produced by the sum of
these two actions is consequently augmented.
In another arrangement I connect with great advantage the pillow of soft iron
carrying the axis of oscillation of the lever to the magnet at the same side and
near to the pole carrying the bobbin in such a manner that the two soft iron.
prolongations have at their ends the same maguetic polarity but at different
rates. The oscillating armature receives, at its end opposite or facing the bobbin
a dissimilar polarity, but the whole is from a magnetic point of view, in a position
of unstable equilibrium which is to be altered by the most minute changes
transmitted in the telephonic circuit.
These telephones may be constituted with a number of magnets each of such
magnets being provided with an armature lever which strikes the same rigid
surface so as to multiply the intensity of each compound blow by the number of
the component blows and consequently strengthen the sound transmitted.
It is evident that the form of the magnet and the mode of fixing the axis of the
armature, the form materials and dimensions and mode of fixing of the lever and of
the intervening rigid or shocked body which transmits the sonorous vibrations to
the ear and the arrangement of the whole apparatus may be varied without
affecting the principle of the Invention.
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 The hereinbefore described improvement in telephones consisting in the
combination of a magnet or electro magnet provided at its pole or poles with coils
of copper wire interposed in the telephonic circuit and an arinature of soft iron or
magnetised steel communicating vibrations by means of a rigid lever to or from a

page_text: rigid body which transmits or receives the sonorous vibrations or conveys the
sound to the ear all arranged and operating substantially as hereinbefore described
and illustrated in the accompanying drawings.
Second In a telephone the employment of a rigid armature lever formed with or
rigidly connected to the magnetic armature arranged and operating substantially
as herein before described and illustrated in the accompanying drawings.
Third In a telephone the employment of an armature lever capable of oscillating
freely upon an axis under magnetic influence the attraction of the magnet being
alone, opposed by the reaction of the rigid body or surface with which the hammer
on the end of the lever is in contact, substantially as liereinbefore described and
illustrated in the accompanying drawings.
'
Fourth In a telephone the employment of an armature lever carrying a hammer
in.contact with the surface of a rigid body substantially us hereinbefore described
and illustrated in the accompanying drawings.
Fifth In a telephone the employment for the "shocked body" of rigid and
inflexible material substantially as hereinbefore described.
Sixth In a telephone the employment of dead or non-resonant materials such
as cork wood. ebonite india rubber and the like for the purpose of immediately
extinguishing the sonorous vibrations the said materials forming the "shocked
body" or being applied to resonant or sonorous materials at the point where the
shocked body receives the blows of a vibrating hammer substantially as
bereinbefore described.
"
.
Seventh In a telephone the employment of means as hercin before described
under various modifications for enabling the distance between the arinature and
the pole of the magnet to be adjusted by means of a screw which moves the axis
of oscillation of the armature lever as illustrated in Figures 1 and 2 of the
accompanying drawings or by raising or lowering the pole or poles of the magnet
or by raising or lowering the "shocked piece" substantially as hereinbefore
described.
1
Eighth In a telephone the combination of an armature lever with a hammer
screwed upon the end of the said lever so as to be capable of adjustment
substantially as hereinbefore described and illustrated in the accompanying
drawings.
Ninth In a telephone the combination of a "shocked body" with a mouth
piece of suitable form hollowed out in the substance of the piece itself in such a
manner that the ear can be applied directly to the "shocked body" substantially
as herein before described and illustrated in figures, 3, 5, 6 and 7 of the accompanying
drawings
Tenth In a telephone the employment of means whereby the sounding box is
enabled to be dispensed with substantially as hereinbefore described and illustrated
in figures 4 to 7 of the accompanying drawings.
Eleventh In a telephone the arrangement herein before described with reference
to figures 3, 4, 6 and 7 of the accompanying drawings in which the axis of
oscillation is connected directly to the "shocked body" in such a manner that the
car receives the effect of the blows produced by tlio action of the body of the lever
on its axis and by the action of the hammer carried by the said lever striking the
"shocked body" substantially as herein before described and illustrated in figures G
and 7 of the accompanying drawings.
Twelfth In a telephone the connection of a pillar of soft iron to the magnet on
the same side and near to the pole carrying the bobbin in such a manner that the
two soft iron prolongations of the magnet have the same 'magnetic polarity but at
different rates, substantially as herein before described.
-
Thirteenth In a telephone the employment of a number of magnets with the
rigid armatures or armature levers in one apparatus so as to concentrato the blows
of all the armatures or levers upon one "shocked body" or rigid piece and thus
5
I...

page_text: augment the, intensity of the sound transmitted substantially as herein before
described.
Fourteenth-İn
a telephone, the employment of means for producing sudden
shocks from or to a rigid obstacle and consequently of instantenous movements of
the armature and of sudden intermittent or pulsatory electrical currents instead of
the inflections of a thin disc or tympan and of undulatory currents as used in the
"Bell" and other telephones for the transmission and the reproduction of sounds
and of articulate speech substantially as hereinbefore described.
In witness whereof I the said John Henry Johnson have to this my
Specification set my hand and seal the Second day of April One thousand
eight hundred and eighty three