Improved Electro-acoustic Telegraph with Morse Transmitter.
Year: 1898

page_text: COMPLETE SPECIFICATION.
Improved Electro-acoustic Telegraph with Morse Transmitter.
I, NICOLAS FLECHTEN MACHER, of No. 8, Strada Paunilor, Bucarest, in the
Kagdom of Roumania, Telegraphist, 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:-
This application for Letters Patent has for its object an improved system of
electro-acoustic telegraph with a Morse transmitter, which permits the transmission
of the signals and the receiving of them by aid of the hearing only without causing
any noise to be perceptible outside and consequently protecting the secrecy of the
despatch.
My improved system includes:
(a) A Morse manipulator constructed in such a manner that persons who are in
the neighbourhood of the apparatus cannot hear the signals transmitted.
(b) A special relay of great sensitiveness having a free armature between the
limbs of an electro-magnet and of a polarized electromagnet.
(c) A telephone receiver enabling the operator to receive by ear the signals
transmitted without allowing persons who are in the neighbourhood to hear them,
the said receiver being combined with a bell apparatus and arranged to be
suspended to a spring lever which closes the local circuit either through the
telephone receiver or through the electric bell circuit according as the said receiver
is suspended or not on the said lever.
In the accompanying drawing I have illustrated by way of example one
constructional form of my invention.
Figures 1 and 2 represent respectively in elevation and partial section and in
plan the Morse manipulator.
Figures 3 to 5 are respectively a vertical section, a plan and a side view of the
special relay.
Figure 6 is a plan view of the electric bell combined with the receiver,
whilst
Figure 6 is an elevation of an automatic lever commutator with which the bell
circuit is provided.
Figures 7 and 8 are two sections at right angles to each other of the receiving
apparatus and,
Figure 9 is an elevation of a commutator combined with the receiver.
Figure 10 is a diagrammatic view of an installation of a telegraph office arranged
according to my system.
MANIPULATOR.
In my improved manipulator (Figures 1 and 2) each of the metallic anvils a a¹
provided at their upper end with contacts a² of platinum, is subject to the action
of a spring a³ so that when the lever L is caused to oscillate, either by pressing
upon the button 18 or by permitting the spring R¹ to force it into its original
position, so as to bring the one or the other of the contact screws s 81 having platinum
tips, in contact with the corresponding anvil a or a¹ the blow of the sail screw
against the corresponding anvil will not produce any noise although the certain
contact between the screw and the anvil is assured. The plate support A° of the

page_text: coils of the electromagnet A connected in tension with the wire of the coils b b¹ of
the magnet B. The terminals 3 and 4 are respectively connected to the supports S S¹
and consequently to the screws w w¹, the terminal 3 is moreover connected to
one of the poles of the local battery E, the other pole whereof can be placed in
communication with the terminal 4 by the interposition of the receiving apparatuses
of the telegraph office. The circuit of this local battery E is indicated in dotted
lines in Figure 10. By the displacement of the screws v v², 20 20², we may
approach or remove the armature to or from the poles of the electro-
magnet A.
Having now described the relay let us investigate what occurs when a current
coming along the line L¹ passes through a¹, and 1 and re-acts upon the relay
supposing that the yoke U of the circular commutator C is in the position shewn in
Figure 4, for example. The current will then pass from 1 first through the wire
of the coils of the electro-maguet A and then through 41, a contact projection
of U, 1 and Z, then through the wire of the coils bb¹ of the magnet B to the piece 3
and from thence through the second contact point of U, 21, 2, L², to earth. In the
electro-magnet A the current will always have the result of causing the excitation
of its pole pieces and in the case now in view, the current passing through the
coils 5 61 of the magnet B will have a magnetising effect, that is to say, it will
augment the magnetisation of the pole pieces d d which thus exercise a more
powerful attractive action upon the bar D. Nevertheless, the action of the electro-
magnet A upon the said bar D will overcome that which is exercised by the pole
pieces dd', and consequently the bar D will be drawn towards the electro-magnet A
the permanent magnet B and its coils b b being proportioned so that the
magnetic field of the polarized electro-magnet B, b, b, d, d' constantly remains
smaller and weaker than that of the electro-magnet A. In the above described
position of the yoke U of the commutator the relay will be caused to work when
strong currents are made use of. But if the current be very weak then in order to
increase the sensitiveness of the relay, the contacts of the yoke U of the
commutator C are placed so as to connect 11 with 21 and 3¹ with 4¹.
In this case
the current coming from 1 will pass as in the preceding case first into the winding
of the electro-magnet A then successively through 4', a contact point of U, 31, the
winding of the coils bb of the magnet B, the piece Z, 11, the second contact D¹
of U, 21 and by way of L² to earth. In this case the effect on the electro-magnet A
will be the same as before but in the pole pieces d d of the coils b b there will no
longer be augmentation of the force of attraction, but on the contrary these pole
pieces will momentarily lose their force of attraction, because the current will act
therein on a demagnetising manner, so that the electro-magnet A will be easily able
to attract the armature D, which will be either not at all or very little attracted by
the polarised electro-maguet B, b, b¹ dd. In the first case we operate with the
differences of force between the polarized electromagnet B b b d d¹, and the electro-
magnet A; whereas in the second case we operate with the combination of both
these forces, because whilst the one arrangement is working the other is not at
work. There are therefore in this latter case two factors which secure a great
sensitiveness and according to practical experiments this sensitiveness will vary in
geometrical progression with the number of the elements of the battery employed.
The important point is that the bar D should be free, that is to say, unaffected by
any mechanical friction. This ensures its sensitiveness. Each time that the
bar D is attracted towards the electromagnet A, that is to say, is drawn down,
it makes contact with the screws w w¹ and closes the circuit of the local
battery E thus actuating the receiving apparatus. As soon as the current is
nterrupted the electro-maguet A loses its attractive force, whereas the
polarized electro-magnet B b b d d regains its power or it may be only
preserves the same and the bar D will be attracted by the pole pieces d d¹ and then
t will no longer touch the screws w w¹ and the circuit of the local battery will be
nterrupted.

page_text: In appearance the receiver (see Figures 7 and 8) resembles a telephone such as
is employed by telephone operators at central stations. It is secured to the head
of the operator by means of a weak spring R, the said spring having only a support
of about sixty grammes. In order that it may not become uncomfortable to the
ear of the user the part W which is adapted to rest against this part has the form
of a trumpet; consequently the ear of the operator remains free and the apparatus
which is moreover very light will not exercise any pressure upon the ear. In order
that the air may not be confined to the ear and in order to avoid the concentration
of the sounds upon the dram of the ear of the operator, the said trumpet W has
certain holes which admit of circulation of the air and the refraction of sounds
to the outside. The box K enclosing the working parts is very small. The trumpet
perforated at its base with the hole y¹ is adapted directly to this box, upon the
edges whereof rests a circular plate or vibrating membrane Q of iron of
about 0.28 millimetres in thickness. The box enclosing the permanent
magnet M. of small size is provided with two poles of soft iron m m¹ wrapped with
windings nn of conducting wire, the ends whereof are attached directly to the cable C²
of two electric wires which are connected to the commutator C¹ (see Figures 9 and 10)
which commutator resembles that of the relay, that is to say, it admits of the
current of the local battery B being caused to circulate in opposite directions
through the windings n n.
The special features of this receiver are the following:-
It requires only a very small current to operate. It requires no other regulation
than as follows:-If it is desired to hear more distinctly the operator reverses by
aid of the circular commutator C¹ the direction of the current of the local battery E
so that it may act in the magnetising direction upon the pole pieces m m¹ of the
polarized electro-magnet of the receiver. If, however, on the contrary it is desired
that the signals be heard less loud, current is reversed so that it acts in a demag-
netizing manner upon the pole pieces m m¹. There is a great difference perceptible
when the current is reversed, because whilst it acts in the magnetising direction
the signals are three times as loud as when it acts in the de-magnetising direction.
The trumpet W and the box K of the receiver are formed of celluloid, this receiver
is combined with an ordinary electric bell I (Figure 6) combined with an automatic
commutator spring lever X (see Figures 6 and 6*). The lever l' upon which
presses a spring 12 and which communicates by means of the terminal a with one of
the poles of the local battery E can come in contact either (1) with the contact
piece connected to the coils 15 of the bell, which coils themselves are connected to
the hammer of the bell, whereas the anvil terminal of this bell is connected by
a terminal with the bar 4, or (2) with the contact piece 14 connected by means
of the terminal to one of the four contact pieces of the commutator C₁ whereof
the contact piece diametrically opposite is connected to the terminal 4 of the relay
and thus closes the circuit of the local battery E, either by means of the commu-
tator Cthrough the coils m m¹ of the receiver or through the coils of the bell,
according as the said receiver is or is not suspended on the commutator lever P.
When the apparatus is not operating the receiver is suspended from the lever and
if the corresponding station sends any current over the line the circuit of the
battery E closes by means of the bar D of the relay which attracted by the
magnet A strikes the screws ww' on the coil of the bell L and the operator receives
the intimation that he is called. He then unhooks the receiver, and on placing it
to his ear he will be in position to hear what is required of him, because the circuit
of the battery E is now connected with the coils of the receiver, the coils of the
bell being cut out. Owing to the arrangement of this apparatus as set forth and
shewn in the diagram (Figure 10) the operator can transmit and receive perfectly
without any other persons who may be present being able to hear the slightest
noise. The operator who is at work and especially whilst he is receiving telegrams
is in no way incommoded; it is impossible to make close to him a very loud noise
r

page_text: without causing him to lose a single signal even when the signals are being
transmitted to him most rapidly.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, declare that what I
claim is:
1. In a system of electro-acoustic telegraph, with Morse transmitter, a
manipulator in which the anvil contacts against which the contact screws of the
lever of the manipulator strike, are supported by springs for the purpose of
minimizing the noise when the said contact screws strike the said anvil contacts
thus ensuring the secrecy of the message transmitted.
2. In a system of electro-acoustic telegraph with Morse transmitter, a relay com-
prising a very light armature having platinized tips placed freely between an
electromagnet fixed in the current circuit, and a polarized electromagnet the coils
whereof may be placed, by means of a suitable commutator in tension with those of
the first electromagnet in such a manner that they can be traversed by the line
current either in one direction or in the reverse direction, so that the action of the
said current in the polarized electromagnet may be added to or subtracted from
what exercised by the first mentioned electromagnet, upon the said armature, the
ascending motion of which is limited by ivory tipped contact screws, whilst its
descending motion is limited by contact screws with platinized tips, these latter
serving in combination with the said armature to close the circuit of a local battery,
for the purpose of obtaining a relay of a very great sensitiveness that is to say
requiring only an extremely feeble line current to operate.
3. In a system of electro-acoustic telegraph with a Morse transmitter, a receiver
characterized essentially by the combination of a box provided with a spring arranged
to fix the receiver to the head of the operator and enclosing a polarized electro-
magnet, the said box being screwed to a trumpet having peripheral apertures and
pierced at the base with a hole, and an iron vibratory plate being interposed between
the open end of the said box and the base of the trumpet, the said receiver being
combined on the one hand with a commutator which enables the electric current to
pass either in the one direction or in the reverse direction through the coils of its
polarized electromagnet for the purpose of varying the intensity of the audible
signals produced at the receiver and connected on the other hand with a bell signal
and a spring commutator lever which permits of the closing of the electric circuit.
upon the said bell signal or upon the said receiver, according as the latter is sus-
pended or not on the said lever commutator.
4. In a system of electro-acoustic telegraph with Morse transmitter a manipulator
constructed essentially as herein before described and illustrated in Figures 1 and 2
of the accompanying drawing.
5. In a system of electro-acoustic telegraph with Morse transmitter, the relay
and its commutator constructed substantially as hereinbefore described and illus-
trated in Figures 3 to 5.
6. In a system of electro-acoustic telegraph with Morse transmitter, in com-
bination, the receiver and its commutator, the spring commutator lever and the
bell signal, constructed substantially as hereinbefore described and illustrated in
Figures 6, 6, 7, 8 and 9 of the accompanying drawing.
7. In a system of electro-acoustic telegraph with Morse transmitter the combina-
tion of parts arranged and connected substantially as hereinbefore described and
illustrated diagrammatically in Figure 10 of the accompanying drawing.
Dated this 90th day of June 1800
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C., Patent Agents for the Applicant.