Improvements in Signalling Apparatus for Telephones.
Year: 1892

page_text: Date of Application, 29th Aug., 1892-Accepted, 8th Oct., 1892
COMPLETE SPECIFICATION.
Improvements in Signalling Apparatus for Telephones.
I, GEORG EDUARD HEYL of 101/102, Leipziger Strasse, Berlin, Kingdom
of Prussia, German Empire, Chemist, 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 :-
:
My invention relates to an improved signalling apparatus for telephones by
means of which a weaker or stronger current may be sent through the line, the
weaker current being employed for giving the usual bell-signal and the stronger
current for enabling the person wishing to transmit a message by telephone, to
operate an ink-writer or other electric recording apparatus, and thereby to produce
in this apparatus letters or signs indicative of its name; in some cases my improved
apparatus is constructed in such a manner that any telegraphic message may be
transmitted by means of the same.
My improved apparatus will enable any person calling another through the
telephone and receiving no answer, to leave a message written with some arbitrary
signs in the apparatus of the other person, so that anybody who has provided
himself with my improved apparatus, is enabled to ascertain who has called in his
absence.
My invention will be more readily understood by reference to the accompanying
drawings, in which :-
Fig. is an elevation of my improved apparatus, a part of the cover being
removed.
Fig. 2 is a representation of a number of signs employed in my improved;
apparatus.
Fig. 3 is a diagram of the electric connections.
Fig. 4 is a detail view showing the construction of the switches.
Fig. 5 is a perspective view of an electro-magnetic apparatus for putting the
bell out of circuit.
Fig. 6 is a front elevation of a transmitting apparatus employed in a modi-
fication.
Fig. 7 is a side-view of the same and of its electrical connections, partly in
section.
Fig. 8 is a sectional elevation of a friction-brake for regulating the motion of '
the same.
Fig. 9 is a side-view corresponding to Fig. 7 of another modification.
Fig. 10 is a diagram of the electric connections in the modification represented
by Figs. 6 & 7.
Fig. 11 is a diagram of the electric connections in the modification represented
by Fig. 9.
Fig. 12 is a modification, in which the electric current is produced by an electro-
magnetic machine.
Fig. 12 is a sectional elevation of an electric switch employed in this modi-
fication.
My improved apparatus as illustrated by Figs. 1-5 is constructed as
follows:
B B is the battery comprising several cells as usual; one terminal of that battery
is connected with the earth-line a², the other terminal is connected to a screw s¹ by
means of the connecting wire e. The screws' is also in electrical connection with
a contact plate gl. One of the cells of the battery B intermediate between the
cells from which the current is taken off to the earth-line a² and to the wire e, in
[Price Sd.1

page_text: connected to the screws by means of the wire a.
The screws is likewise in
electrical connection with a contact plate g. The electrical connections from the
battery B to the wires a² a e are such, that the wires a and e are in connection with
like poles of the battery, whereas the wire a is connected to the opposite pole;
for instance if the wires a and e are each connected to a negative pole, the wire a
will be connected to the positive pole. The contact plates y glare adapted to
cooperate. with switches b and c respectively. These switches are constructed in
like manner, I will therefore describe but one of them with reference to Fig. 4.
On the same plate to which the screws is secured, I have fixed the bearings
for the pivot of the lever ¹³ constituting the switch proper. The arm h² is
provided at its end with a rounded head which is, as a rule, kept in contact with
a metallic or conducting plate p, by means of a spring. The other arm ' is
provided with a pin having a head by means of which the arm 4 may be brought
in contact with the plate g. In Fig. 3I have lettered the parts of the switches /:
and e in a corresponding manner. The contact plate p of the switch bis electrically
connected to the pivot of the switch c. The pivot of the switch is connected
to the line by means of the wire a³. The contact plate of the switch c is con-
nected to the ink-writer M by means of the wire m and to the usual electro-
niagnetic click and ratchet-wheel work M' for reeling off the slip of paper
(Fig. 1). Another wire n puts the ink-writer M in connection with the coils of an
electromagnet o secured to a plate d. The parts connected with this electromagnet
are shown more clearly in Fig. 5. The flat spring secured at a is connected to
the coils of the electromagnet o by the wire and is normally in contact with a
conducting stop t'. To the side of the spring facing the poles of the magnet o
I have secured the armature m'. Opposite the conducting stop and normally
out of contact with the end of spring I have provided another stop likewise
of conducting material and located in such a manner, that it will prevent the
armature m froin coming in contact with the cores of the electro-magnet o when
attracted by the same. The stop 2 connects with the earth line a' by means of the
wire u
The stop is connected, by means of the wire u, to one of the screw terminals
of an electric bell G constructed as usual; the other terminal of this bell connects
with the earth line a by means of the wire v. It will be understood that the
apparatuses of all telephonic stations are arranged in like manner, that is to say,
all switches corresponding to switch bare connected to the line, one terminal of
each bell is connected to the earth, and so on.
In Fig. 3 I have shown the different parts of the apparatus and their electrical
connections only diagrammatically, and it will be understood that the arrangement
of these parts may be varied to a wide extent, as the essential point is to have the
electrical connections made in the right manner.
The construction illustrated by Fig. 1 is a very condensed one, all parts being
provided within the casing of the bell G, for this purpose the casing may of course
be of larger size than usual.
The operation of this apparatus is as follows:
In order to give the usual bell signal, the head or button k is pressed so as to
bring the arm against the contact plate g, a weaker current from the battery B
will then flow through the wire a, the screws, contact-plate g, switch-arm. ',
pivot and wire a³ to the line and will enter the apparatus of the distant station
by the pivot of the switch b, proceeding therefrom to the switch-arm, the
head 9, contact plate p, wire i, pivot of the switch c, switch arm, contact
plate p' and wire m to the ink-writer M and the apparatus M' for setting in motion
the paper-scroll p².
This current is however not strong enough to operate the apparatuses M and M¹.
The current proceeds farther through the wire n, the coils of the electro-magnet o,
the wire r, the spring, contact-plate t' and wire u to the bell G which is operated
by the current and gives the usual signal. The magnetism excited in the cores of
the electro-magneto by this weak current is not strong enough to attract. the

page_text: armature m³ and to break the circuit between the contact stop t¹ and the spring z.
From the bell G the current flows to the earth through the wires » and «².
When receiving no answer after giving the bell-signal the employer of the
apparatus releases the button k, so that the arms ¹³ of the switch re-assume
their original position, as shown in Fig. 4. He then presses the corresponding
button of the switch c. Thereby the arm h³ of this switch is brought in contact
with the plate gl and the electric circuit is broken between the switch-arm /* and
contact plate p². The stronger current of the entire battery B will now flow
through the wire e to the screw s', contact-plate g', switch-arm ³, pivot , wire i,
contact plate p, switch arm ², pivot and wire a³ to the line and to the pivot of
the switch in the apparatus of the other station, From here the current will
proceed to the ink-writer M and its auxiliary apparatus M in the same manner
as before described; the current being however stronger, its force will be sufficient
to operate these apparatuses. From the ink-writer M the current will flow
through the wire n the coils of the electro-magnet o, the wire r, the spring,
stop t, wire u, bell G, wire and wire a³ to the earth line. This current is how-
ever strong enough to attract the armature m¹ of the electro-magnet o and thus to
hold the spring against the contact stop 2.
:
=
The circuit will therefore be changed almost momentarily, and the current,
instead of flowing from the spring through the bell G, will proceed directly to
the earth line through the stop 2 and the wire ul. It will be obvious that by
alternately pressing and releasing the button of the switch the circuit will be
alternately closed and broken and the ink-writer M will thereby be operated in
the same manner as any of the usual telegraphic recorders. It will be further
obvious that by keeping the button of the switch c pressed down for a more or
less considerable while, signs may be obtained on the paper scroll p³ of the ink-
writer M, which are of the same kind as those obtained in an ordinary Morse
apparatus. The employer of my improved apparatus will thus be enabled to
produce in the station of the person to which he wishes to speak, any con-
ventional signs whereby he may leave a notice of his having called for that
person. When wishing to indicate only the name of the person who has called,
I prefer to produce in the writing receiver only signs representing a number,
and each subscriber to the telephone would have his particular number, so that
the name could be easily ascertained by means of the official lists. In this case
I prefer "not to employ the usual Morse sigus, which would be unnecessarily
complex, but to use the signs shown in Fig. 2 of the drawings or their equivalents;
these signs are the simplest possible and will be found very convenient for the
stated purpose.
Of course any message of the usual kind, written with the
Morse alphabet, may be transmitted by means of my before described improved
apparatus.
In Figs. 6, 8 and 10 I have shown a modification in which an automatic rotatable
disc is substituted for the switch c used for transmitting a stronger current through
the line. This modification is represented diagrammatically in Fig. 10. By
comparing this figure with Fig. 3, it will be seen that the only difference resides in
the substitution of the mentioned rotatable disc for the switch c. It will be sufficient
therefore to describe that part of the apparatus and its electrical connections. In a
frame F, preferably made of wood or another non-conducting material, I provide the
bearings for the shaft c', at the outer end of which a crank and a suitable handle
are secured. To the shaft c¹ I also secure one end of a helical spring d', the other
end of which is secured to the pin e³. The shaft c' carries a disc a' at its inner end,
this disc having a notch of the form shown at its upper end, that is to say, one
side of this notch is cut radially in a straight line and the other is curved so as to
effect a gradual transition to the periphery. The disc a' is made of a non-conducting
material, but provided with a series of conducting contact plates on its
circumference and its face. These contact-plates are all in electric connection with
the shaft and are made of different lengths so as to correspond to the signs which
it is desired to produce in the ink-writer. A lever provided with a handle g² is

page_text: :
.
pivoted to the frame F and carries a pin f¹ adapted to be pressed into the notch.
by means of a spring . A sliding contact spring k¹ is located within the apparatus
and arranged in such a manner, that it bears normally on a non-conducting portion
of the periphery of the disc a¹. Another contact spring k², likewise adapted to
slide on the circumference of the disc a', is also secured to the frame F; the
position of this contact-spring is however such, that in its normal position (that is to
say, when the pin is pressed into the notch q¹) it is in contact with one of the
conducting plates b¹ on the periphery of said disc. The contact plates are
arranged in such a manner, that during the rotation of the disc a¹ the springs k¹ k
never will be simultaneously in contact with any two of these contact plates. Another
sliding contact spring is secured to an angle extending from the frame F and
is kept in contact with the shaft c¹. Finally I also secure to the frame F a plate m²
in which I provide a female thread for a screw n¹, this screw being adapted to
against the semi-cylindrical ring o¹ provided on its inside with a cover p of felt or
similar material; this cover is in contact with the shaft c¹ and acts as a brake
regulating the rotation of the same. The disc a and the parts directly connected
press
to the same may be covered by a casing s², the handle g remaining however
outside of the casing.
The electric connections of this part of the apparatus are as follows:
A conducting wire el connects the contact plate p of the switch with the
contact spring; the contact spring 2 is in electric connection with an ink-writer M
by means of the wire e² and the contact spring & with one terminal of the battery B
by means of the wire e.
The operation of this modification is as follows:
In order to give the bell signal the button of the switch bis pressed so that the
arm of this switch comes in contact with the plate g, then a weak current will be
sent from a part of the battery B through the wire a, screws, contact-plate g,
switch arm, pivot and wire a³ to the earth line. This current will enter the
apparatus of the other station through the pivot of the switch b, and as this switch
is in its normal position, the current will proceed through the switch arm /², the
contact-plate 2, wire e¹, spring 1, shaft c, one of the contact-plates 6 contact
spring and wire e to the ink-writer M and its auxiliary apparatus M. These
apparatuses will not however be operated by the weak current, exactly as in the
before described modification. The flow of the current from the ink-writer M to
the bell G and the earth line a will be exactly the same as described with reference
to Fig. 3, so that I need not repeat this in particular. It will be obvious that the
current will operate the bell G to give the usual signal.
2
When receiving no answer the employer of the telephone apparatus will release
the switch so that the same re-assumes its initial position, and will then raise the
pin out of the notch q¹ by means of the handle g². The shaft c' will then be
rotated with the disc a' by the spring d¹.
The flow of the current will now be the following:
The full current of the battery B will proceed through the wire e to the contact
spring and will be transmitted farther only when this spring slides over one of the
contact-plates on the periphery of the disc a¹. As I have observed above, the
spring will never rest on one of the contact-plates b' when the spring is in
contact with one of the same, so that the current will in no case be able to flow to
the spring during the rotation of the disc. The current transmitted to the
contact-plates by means of the spring will proceed to the shaft c. the contact-
spring 2, wire e¹, contact plate p, switch-arm h², pivot l, wire a³ and the line. From
the line the strong current will enter the apparatus of the other station by the
wire a and pivot 7 of the switch b. The current will hereafter flow through
the switch-arm 2, the contact plate p, wire e', contact spring 12, shaft c', one of the
conducting-plates 6 of the disc a' (which is of course in its initial position), contact-
'spring and wire e to the ink-writer M. The strong current will be sufficient to
operate this part of the apparatus. The further flow of the current will be as
described with reference to Fig. 3, that is to say, the armature m¹ of the electro-

page_text: magneto being attracted, the bell G will be put out of circuit and the current
proceed to the earth line a² directly through the wire u. It will be obvious that
the circuit will be alternately closed and broken between the contact spring and the
rotating disc a. Accordingly the lever of the ink-writer M will be alternately
attracted and released. It will be further obvious that the signs produced on the
paper scroll of the ink-writer M will correspond in length to the several contact
plates on the periphery of the disc a'. Therefore by a suitable arrangement of
these contact plates any number desired may be marked on the paper scroll by
means of the signs represented in Fig. 2, or of similar signs. After a complete
revolution of the shaft c¹ the pin ", which slides on the periphery of the disc a', will
be drawn into the notch by the spring, and the rotation of the disc and shaft will
be stopped. As the tension of the spring d will decrease gradually, it will be
necessary to wind it up from time to time, this being accomplished by means of the
crank and its handle.
I may also dispense with the spring and the crank t³, when turning the disc a¹
lirectly by means of a handle as indicated at 1, Fig. 7. In this case the
casing would also be dispensable or at least the same would have to be constructed
in such manner that the handle 2 would remain outside the same.
Instead of the disc a', 1 may employ a rod of non-conducting material, which
would be provided with conducting contact-plates corresponding to those marked
on the drawings, and also with contact-springs corresponding to and. This
rod would be enclosed within a suitable sleeve and operated by drawing it out so as
to alternately close & break the circuit between the contact spring and the plates b¹³,
then the rod would be turned around its axis and pushed back, so that during the
backward movement the spring would not come in contact with the plates b¹.
Finally the rod would again be turned in the opposite direction so as to bring it
into its initial position.
3
In Figs. 9 and 111 have shown a modification of the apparatus which I have
just described. In this.ification it is not necessary to raise the pin f¹ by hand,
but this is accomplished by electromagnetic action when pressing an ordinary
contact button. This modification comprises the following additional parts: g³ is
the mentioned button, adapted to be pressed on the contact plate g; the button g³
is in electrical connection with the wire e and the contact plate with the coils of
an electro-magnet. The other end of these coils is connected to a metallic stop-
pin by means of the conducting wire y'. This pin ¹ is normally in contact with
one end of the lever / pivoted at 2, the other end of this lever is provided with
a pinas before described. The pivot 2 is in connection with the earth line a².
To the lever an armature o² is secured opposite the cores of the electro-magnet.al.
The other parts of the apparatus are constructed as before described.
This modification operates as follows:
The bell signal is given by pressing the button of the switch bas described. The
flow of the current in this case will be exactly the same as described with reference
to Fig. 10. Now when wishing to operate the ink-writer M, the button ³ is pressed
on the contact-plate g, the full current of the battery B will then flow through the
wire e, the button 3, contact plate g, coils of the electro-magnet x¹, conducting-
wire y', pin, lever hand pivot to the earth line a². The armature o will
thereby be attracted towards the cores of the electro-magnet r¹ and the pin raised
out of the notch g', so that the disc a¹ will begin to rotate; at the same time the
circuit will be broken between the pin and lever ³. The passage of the current
through the coils of the electro-magnet to the earth will then be no more possible,
and the current will flow from the contact-spring through the plates b' and
further on to the line a³ and the apparatus of the other station in the same manner
as described with reference to Fig. 10; I therefore need not state again the
different parts to which the current is successively transmitted. In this modification
the casing may cover the entire front of the apparatus with the exception of the
button g³.

page_text: or a².
Whereas in all the forms of construction herein before described I have employed
a galvanic battery for producing the requisite weaker and stronger currents, I have
shown in Figs. 12 & 12ª a modification in which an electro-magnetic or dynamo-
electric machine is used for the same purpose. The disc is secured directly to
the shaft of the machine D. The shaft 2 is however insulated from the machine
itself but in electric connection with the conducting parts of the disc a' and with
another disc likewise mounted on shaft c² and made of a conducting material. A
sliding contact spring pivoted at may be laid on either of the discs
This spring is provided with a lug adapted to rest on an insulated conducting
support when the spring is shifted on the disk 3. The support g³ is in electric
connection with a resistance coil w and this coil is again connected to the earth
line a². To the spring 2 there is secured an arm of non-conducting material,
which will press a spring on a contact plate when the spring is laid on the
disc a'. The spring is connected by the wire e, with a sliding spring normally
in contact with one of the conducting plates 6 of the disc a'. The contact plate 3
is connected to the ink-writer M by means of the wire e².
3
In the initial position the spring will lie on the disc a'. The shaft 2 is in
electrical connection with the line by means of the wire a³. One pole of the machine
is connected to the pivot v of the spring f by means of the wire «, and the other
pole of the machine is connected to the earth line, or to the end of the resistance
coil w, this having of course the same effect. The parts of the apparatus included
in the circuit between the ink-writer M, the bell G and the earth line a² are con-
structed and connected with each other in the same manner as before described.
The operation of this apparatus is the following :
In order to give the bell-signal the spring is laid on the disc s³ so as to simul-
taneously break the circuit between the spring and contact plate then the
shaft of the machine, on which the armature of this machine is mounted, is turned
by means of a suitable handle; thereby a continuous electric current will be
generated, which will flow to the spring 2 through the wire a, part of this current
will flow to the earth through the lug f³, support 93, and resistance coil tv, so that
only a weaker current will be transmitted to the apparatus of the other station
through the disc, shaft c² and line a³. The current will enter the other apparatus
by the shaft and will flow through one of the contact plates of disc a¹ to the
contact spring thence to the spring 2, the contact plate (in the apparatus of
the other station the spring 2 is in its original position and therefore the circuit is
not broken between the spring &² and contact plate v³) wire e³ and ink-writer M, the
latter however will not be operated, as the current is not strong enough to effect this.
The current will further proceed to the bell G in the manner before described.
When wishing hereafter to employ the apparatus as a telegraphic apparatus, the
spring is turned back so as to lie on the circumference of the disc a'. The con
tact-plates on this periphery and the springs f** are arranged in such a manner
that the springs f f never will be in direct electric connection with each other by
the shaft c², that is to say, when one of the springs lies on a conducting part of the
periphery, the other will bear upon a non-conducting part and vice versa. The
shaft is then turned in the same manner as before and the current flowing from
the machine through the wire a to the spring f2 will be conducted through each of
the plates &', as the same come in successive contact with the spring, to the
shaft and the line a³. It will be obvious that this current is stronger than that
-employed before, as the full current of the machine is transmitted to the line.
the apparatus of the other station the current will flow through the wire a³ to the
shaft, c², one of the conducting plates of the disc a', the spring fin contact with
the same, the wire e, the spring v³, contact plate and wire e² to the ink-writer M.
The strong current will be sufficient to operate the ink-writer, and it will be obvious
that the signs produced on the paper-scroll will correspond to the length of the
several contact-plates of the disc a'. The bell G will be put out of circuit by
the electro-magneto in the same manner as in all the before described forms of
-construction.
In

page_text: 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..The combination, with a telephone and its signalling bell, of an ink-writer or
other suitable telegraphic recording apparatus, and means for transmitting at will
either a weaker current to actuate the bell, or a stronger current to operate the
ink-writer or equivalent apparatus, for the purpose set forth.
2. The combination, with a telephone and its signalling bell, of an ink-writer or
other suitable telegraphic recording apparatus, a suitable switch for transmitting a
weaker current to actuate the bell, and another switch for transmitting a stronger
current to operate the ink-writer or equivalent apparatus, for the purpose set
forth.
3. The combination, with a telephone and its signalling bell G, of an ink-writer
or other suitable telegraphic recording apparatus M M', a switch for transmitting
a weaker current from the battery B to the apparatus of the other station and
operating the bell of that station, another switch for transmitting the full current
of the battery B to the apparatus of the other station and operating the telegraphic
recorder of that station, and means for automatically putting the bell out of circuit
when the stronger current is employed, for the purpose set forth.
by
4. In an apparatus of the kind described the switch b, having pivot and switch-
arms, the former being adapted to be pressed against a contact-plate
means of a button k, and the latter being normally kept in contact with the con-
ducting plate p by means of the spring, substantially as described with reference
to Fig. 4 in the accompanying drawings, for the purpose set forth.
5. In an apparatus of the kind described an auxiliary apparatus included in the
circuit between the electric bell G and the telegraphic recorder M, and adapted to
put the former out of circuit when the stronger current is employed, said apparatus
consisting of an electromagnet o, a conducting-wire n connecting the coils of the
same with the telegraphic recorder M, another wire for conducting the current to
a spring, having an armature m', said spring being normally in contact with a
conducting stop t' connected to the bell G, and being pressed on another conducting
stop t, connected to the earth-line, when the stronger current flows through the
coils of the electromagnet o and the latter attracts the armaturem, substantially
as described with reference to Fig. 5 in the accompanying drawings for the purpose
set forth.
6. The combination, with a telephone and its signalling bell, of an ink-writer or
other suitable telegraphic recording apparatus, a switch for transmitting a weaker
current from the battery to the apparatus of the other station and operating the
bell of that station, and a rotatable disc or a sliding rod of non-conducting material
provided with a series of contact-plates for transmitting a stronger current at
intervals corresponding to the signs to be produced in the telegraphic apparatus of
the other station, for the purpose set forth.
7. In an apparatus of the kind as set forth in Claim 6: the combination with the
rotatable non-conducting disc a', having contact-plates on its circumference, of
suitable means for rotating said disc, a pin "adapted to snap into a notch q¹ on the
periphery of the disc and thereby to arrest the latter after one revolution, a handle o
for raising the lever and the pin secured thereto, a spring for pressing said
pin on the disc a', a sliding spring normally in contact with a conducting portion
on the circumference of the disc a', and another sliding-spring k', bearing normally
on a non-conducting portion of the disc, the electrical connections of the parts being
substantially as shown in Fig. 10 and described with reference thereto, for the
purpose set forth.
8. In an apparatus of the kind set forth in Claim 6: the. combination, with the
rotatable non-conducting disc a', having contact-plates 6 on its circumference, of a
helical spring d for rotating said disc, a pin f¹ adapted to snap into a notch g¹ ou
the periphery of the disc and thereby to arrest the latter after one revolution, a
handle for raising the lever and the pin f¹ secured thereto, a spring i for

page_text: pressing said pin on the disc a', a sliding spring normally in contact with a
conducting portion on the circumference of the disc a', another sliding-spring,
bearing normally on a non-conducting portion of the disc, and a contact-spring
bearing on the shaft c¹ of the same, all parts being constructed and electrically con-
nected substantially as shown in Figs. 6, 7 & 10 and described with reference thereto,
for the purpose set forth.
9. In the combination of parts as set forth in Claims 7 & 8: the addition of a
brake constituted by the plate m², screw n', half cylinder o' and cover p of felt or
similar material, substantially as shown in Fig. 8 and described, with reference
thereto, for the purpose set forth.
10. The combination, with a telephone and its signalling bell, of an ink-writer or
other suitable telegraphic recording apparatus, a switch for transmitting a weaker
current from the battery to the apparatus of the other station and operating the
bell of that station, and a rotatable disc a¹ of non-conducting material provided with
a series of contact-plates 6' for transmitting a stronger current at intervals corre-
sponding to the signs to be produced in the telegraphic apparatus of the other
station, à pin f adapted to.arrest.the rotation of the disc a' after one revolution of
the same, and a lever normally in contact with a conducting stop 2, and an
electro-magnet adapted to raise the pin f¹ when the button g³ is pressed on the
contact-plate g, the electromagnet being simultaneously put out of circuit, substan-
tially as shown and described with reference to Figs. 9 and 11, for the purpose set
forth.
11. The combination, with a telephone and its signalling bell, of an ink-writer or
other suitable telegraphic recorder, a magneto-electric or dynamo-electric machine,
a switch adapted, when in one of its positions, to conduct a part of the current to
the earth, and the remaining weaker current to the apparatus of the other station to
operate the bell of that station, whereas when the switch is in its other position, the
full current of the machine is conducted at intervals corresponding to the signs to
be produced, to the other station to operate the telegraphic apparatus, means for
putting the bell out of circuit when the stronger current is employed, and means
for preventing the current to pass through the apparatus of the station at which it
is produced, for the purpose set forth.
12. The combination, with the electro-magnetic or dynamo-electric machine D
having a shaft insulated therefrom, of a metallic disc sa and a non-conducting
disc a both secured to shaft e², a sliding spring f normally in contact with one of
the conducting-plates arranged on the periphery of disc.a' and in electrical con-
nection with shaft e², a switch constituted by a spring pivoted at ' and adapted
to conduct part of the current to the earth through a resistance-coil w, when laid on
the discs, a telegraphic apparatus M M', a telephone and its bell G, means for
putting the latter out of circuit when the telegraphic apparatus is operated, and
means for automatically putting the telegraphic apparatus and the bell of the
transmitting station out of connection with the contact spring by laying the
switch-spring f2 on the disc 3, and restoring that connection by laying said spring
on the disc a', substantially as shown and described with reference to Fig. 12, and
for the purpose set forth.
13. In the combination of parts set forth in Claim 12: the spring f³, pivoted at ¹,
and having a non-conducting extension f³, and a lug f³, secured to the spring
proper, in combination with a small conducting support lying in the path of
travel of the lug f³, a fixed contact-plate v³, a spring 2 adapted to be pressed on
said contact-plate by the extension 5 when the spring is laid on the disc a',
and electrical connections substantially as shown and described with reference to
Figs. 12 and 124, for the purpose set forth.
Dated
1
GEO. THOS. HYDE,
4, Moorfields, Fore Street, London, E.C., Agent for the Applicant.