Multiplex and Duplex Printing Telegraph.
Year: 1898

page_text: Date of Application, 31st May, 1898-Accepted, 9th July, 1898.
COMPLETE SPECIFICATION.
Multiplex and Duplex Printing Telegraph.
I, ALBERT SILBERMANN, of Blumen Strasse 74, in the City of Berlin, in the
German Empire, Manufacturer, 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 present invention has three purposes:
1. The production of a new system of printing telegraphy, which is distinguished
from all previous systems on account of its striking simplicity.
2. The use of a single line and of a single apparatus in order to send and receive
messages simultaneously or intermittently.
3. The simultaneous transmission of 2, 3 or more messages and simultaneous
receipt of the same number of printed messages over a single line, the transmitter
and receiver being united in one instrument.
On the accompanying drawings.
Fig. 1 shows two stations connected by the line L, the station on the right
being the transmitting station, and that on the left the receiving station.
Fig. 2 is a front view of the apparatus,
Fig. 3 a side view of the same.
Fig. 4 is a detail view showing a disc for effecting the insochronic motion.
Fig. 5 is a perspective view of the apparatus.
The fixed insulated discs A A¹ are provided at the circumference with a number
of metal strips or layers s s¹, each of which is connected by means of the wires s
with a key of the lettered key-board K. Between these metal strips s s¹ are metal
strips e el, in electrical connection with each other, and connected with the earth
by a wire passing around the coils of the electromagnet R¹. The wires from the
key-board K conducts through the coils of the magnet R to the battery B, the other
pole of which is connected to the earth.
On the axes xx are mounted pointers z z¹ each provided with a contact brush,
which on revolution of the axes glides over the metal strips s s¹, e e¹,. By means
of suitable driving mechanism the axes r¹ are set in motion simultaneously with
the printing-wheels T T', (Fig. 2) mounted upon them, beneath which the paper
strips for receiving the messages are caused to pass.
The strip is pressed against the printing-wheel as soon as the electro-
magnet R (or R¹) attracts its armature h (or h¹), thereby raising the roller g (or g¹).
The position of the types on the printing-wheel must be such, that at the moment
when the paper strip is pressed against the wheel, that type is opposite the paper,
which corresponds to the letter on the key, the operation of which has caused the
armature to be attracted. By means of the same electromagnets the advance of
the paper strip is effected, as is best seen from Fig 3. The armature his connected
with a bent lever 2, 4, 3 which carries on the arm 3 the catch 5, borne against
the escapement-wheel 7, by means of a spring. The escapement wheel 7 drives a
pair of rollers, between which the paper strip is pressed, and consequently advanced

page_text: as they rotate. As often as the armature h is drawn down by the electromagnet,
the paper strip is thus advanced, and on the armature being released, the catch 5
springs into the next tooth of the escapement-wheel 7. uu (Fig. 2) are the inking
rollers for the printing wheels TT.
If two apparatuses are to be worked together, it is necessary that the pointers z z¹
move absolutely synchronously. In order to effect such movement, in addition to
the metallic strips mentioned, the discs A A' are provided with additional
strips cc (Fig. 1) connected to the electromagnets 661 by means of the wires 11.
These wires (or 1) can by means of the switch v, be connected either with the
battery m (or m¹), or to the earth. An arresting device is also provided, as shown
in Figs. 2 and 3. On one end of the armature of the electromagnet b is a projec-
tion y, which
engages with the fly w of the driving mechanism, and on the other end
is the pin i, which takes into a slot o in the disc n (see Fig. 4) when the armature
is not attracted by the magnet b. The position of the slot o corresponds with
that of the pointer on the strip c. If a message is to be transmitted,
the wire has first to be connected to the battery m by means of
the switch v. When the arresting device is in action, however, the
pointer z stands at c, and the pointer at c¹, and consequently the circuit
is made through the line L connected with the axes a and a¹, so that the
magnets and 6' attract their armatures, and the arresting mechanism is set out
of gear.
As long as the pointers rotate with equal speed, both reach the contacts c and cl
simultaneously, so that the magnets and 6¹ attract the armatures at the right
time in order to prevent stopping of the driving mechanism; whereas on one pointer
moving too fast the driving mechanism is so long stopped until the other pointer
has caught up the former."
Furthermore for working the two apparatuses in conjunction it is necessary that
the strips on the discs A and A¹ are so applied that there is always one pointer
lying against one strip s when the other is on a strip e. The circuit is completed
as soon as the pointer makes contact with that strip which is in connection with
the key which is depressed. The circuit is then as follows (Fig. 1): From the
battery B, through the magnet R, through the depressed key of the board K to
the strip s standing in electrical connection with it; from there through the
pointer z to the line L, to the pointer z¹, through a strip e¹ and wire e² to the
magnet R¹ and thence to earth. The armatures of the magnets R
and R of both the transmitting and receiving instruments are there-
fore attracted, and the type corresponding to the letter on the key which is
depressed is printed upon the paper strip.
Both stations are fitted out with key-board, battery and earth-connection for
the strips e, and the pointers brush against the strips e and s alternately and
independently, so that at any given moment the current can only pass in one
direction or the other. It therefore follows that the receiving instrument can be
used simultaneously as transmitter without interfering with its function as
receiver.
It is evident from the construction of the apparatus that the key of the board K
must be depressed so long until the pointer has made one revolution, which may be
signalled by means of a bell.
The arrangement for duplex telegraphy can be seen from Fig. 2. T is the
printing-wheel of the transmitter and T of the receiver; that is to say, the letters
of the former correspond to the transmitter strips s and receiver-strips e¹ and of
the latter to the transmitter strips s and receiver-strips e. The printing-
wheel T serves solely to control the message transmitted.
The current can only be sent to and received from a station alternately, since
at the station where the pointer contacts with a transmitter-strip, a message can only
be transmitted but not received; whereas similarly, where the pointer contacts
with a receiver-strip, at such station a message can only be received, but not
transmitted. It is clear from this that whilst a message is transmitted from one

page_text: station, which is reproduced simultaneously by the printing-wheel T, a message
can be received by means of the printing-wheel T¹.
If it is desired to telegraph over a single line a number of messages in both
directions simultaneously, that is on the multiplex system, a corresponding number
of transmitting and receiving instruments must be set up. The metal strips can
be so arranged either that, for instance with four instruments, the corresponding
strips standing in connection with a key-board each occupy a quadrant; or, the same
letter can be arranged one, two, or more times in succession, so that the one letter
belongs to one transmitter, the next to the second transmitter and so on.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
1. A multiplex and duplex printing telegraph, consisting of discs A A¹ arranged
respectively at the transmitting and receiving stations, provided with sets of
metallic strips s e and s¹ el, each set insulated from the other, in such manner that
the one set of strips s or s¹ on each disc is in electrical connection with the key-
board of a printing-wheel T or T₁, whereby by depression of one of the keys,
circuit is made with the strips s of the transmitter, or e¹ of the receiver and vice
versa, by means of a pointer z or z¹, provided with contact brush and mounted and
rotating upon an axis a or a¹ in common with two printing wheels T T¹, said
wheels printing upon strips of paper advancing below them, with the types which
correspond to the lettered keys depressed, all substantially as set forth.
2. In the apparatus as claimed in Claim 1, the combination of an arrangement
for effecting or controlling the isochronic motion of the axis of the transmitter,
and of the receiver, by means of a regulating current which simultaneously
releases the fly w of the driving mechanism at the transmitting and receiving
stations, substantially as set forth.
Dated this 21st dave of Ma... 1000