Arrangement for Transmitting Telegraphic Messages in Contrary Directions Simultaneously over a Single Wire.
Year: 1898

page_text: Date of Application, 14th Feb., 1898-Accepted, 30th July, 1898
COMPLETE SPECIFICATION.
Arrangement for Transmitting Telegraphic Messages in Contrary
Directions Simultaneously over a Single Wire.
I, MAX BERNSTEIN, Proprietor of the Firm of Joh. Friedr. Wallmann & Co.,
of Blumen Strasse 74, in the City of Berlin, in the German Empire, Patent Agent,
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 object of the present invention is the perfection of the system of so-called
multiplex telegraphy. By means of this invention from any one station two
or more messages may be transmitted and received simultaneously over one wire.
The two stations from and at which the messages are respectively transmitted
and received simultaneously, may be at any desired distance from each other.
each a similar apparatus is required, oue such being shown on the accompanying
drawing.
At
The apparatus consists of two cam discs mounted on an axis of non-conducting
material, said discs receiving an isochronal rotation at each station, and so regulat-
ing their movement automatically, that a simultaneous contact is impossible.
These cam discs are in electric connection with their respective transmitters;
and by means of frictional spring-arms arranged on a rocking axis, of a metal
bar, and of peculiarly arranged relay, are likewise in electrical connection with
their receivers. The connection is such that on rotation of the discs the circuit
to the receiver is broken by means of the cams.
On the accompanying drawing:
Fig. 1 shows the general arrangement of a station.
Fig. 1 a side view of one of the two contact discs, with the cams of the second
disc shown in dotted lines.
Fig. shows another form of the arrangement, in which, instead of the two
cam discs, an arm rotates on a stationary disc.
The axis A is of non-conducting material, and is mounted at each end in such
manner that it can be rotated by means of clockwork C. The movements of
the clockwork C, i.e. of the axis driven by it, are isochronal.
On the axis A two metal discs or wheels U¹ U2 are mounted, having at their
periphery two projections, or cams, b and c. The position of these cams is such
that those on the one disc U₁ come exactly opposite to the centre of the free
surface of the other disc, and vice versa. The cams b and c are of such size that
they each occupy less than one-eighth of the whole surface of their disc.
On the rocking axis B are secured two arms m, n, which in their position
of rest lie with one end bearing upwardly against a cross bar g, whilst the other
end of each lies freely on the periphery of one of the two cam discs U1 U2. When,
therefore, one of the cams in passing under one of the arms m, n raises the latter,
receding it from the cross bar g, the other arm m or n is simultaneously caused
likewise to recede from the cross bar g. On the other hand, both arms m, n
always come into contact with the cross bar g at the same moment, after a cam
has passed.

page_text: The bar y is provided with a binding screw v, which forms the terminal receiving
the current from the line L; whilst a similar binding screw v₁ on the rocking
axis B forms the terminal for transmitting the current to the line.
If the arms m, n are in their position of rest (as shown in Fig. 1), and therefore
in contact with the cross bar g, the circuit from the terminal v¹ is completed through
the arms m, n and bar g, the terminal v, the receivers R2 R¹, to earth. When,
however, the arms m, n are raised by the cams b and c on one of the discs U¹ U²,
the circuit through the terminal vis broken, and the current passes from the
terminal through the axis B, discs U¹ U2 and friction contacts 15 and 16.
As already stated, R¹ R³ on the drawings indicate the receivers (relays, Morse
apparatus), TT being the sounders for the transmitters.
On operating one of the latter, the current passes from $1 or S directly
through or 2 respectively, through the friction contacts 15 or 16, and when
the arms m or n are in contact, through the cams b or e and terminal v to the
wire L.
Should contact be made at the other end of the line, i.e. at the other station,
the current will then pass from there through the line L, terminal v¹, arm morn,
and in event of there being no contact with one of the cams 6 or c, through the
cross bar g, terminal and receivers R2 R¹ to earth.
The axis A is shown on the drawings as receiving isochronal rotation by means
of clockwork C, but it may be similarly rotated by means of a pendulum or the
like. This isochronal movement is effected automatically in such manner that
whilst at one end of the line a cam 6 or c is making contact with an arm m or n,
at the other end no such contact is being made.
If the key T (Fig. 1) operates, the battery S¹ comes into operation as often
as the cams c or b make contact with the arm m. This battery sends a current
in one direction, whilst the battery $2 acts in the contrary direction. The latter
operates similarly, on the key T2 making contáct, through s2, 16, etc. Supposing
that at the other end-at the receiving station-the system of arms m, n makes
contact with the cross bar g, then as often as one or other of the cams b, c at
this the transmitting-station comes in contact with the said system, at the
receiving station the corresponding receiving apparatus R1 R2 operates.
As, however, the apparatuses are oppositely polarised, the one will only be in-
fluenced by a current from the battery 'S', and the other only by a current from
the battery S2; or, what is the same thing, they are operated only by the keys T', T2
respectively, which are in circuit with the batteries S¹ S².
If now the discs U1, U2 at the two stations rotate independently as described,
the connections mentioned between the two stations are made alternately in rapid
succession, each of the individual impulses of current having its special effect.
It follows, that with the described arrangement, two messages may be trans-
mitted and two received simultaneously at one and the same station.
For regulation of the isochronal rotation of the axes A at each station, a relay d
(Fig. 1) is arranged, making and breaking the circuit immediately the
cams (or c) at each station raise the arms m and n. For this purpose one of the
keys, for instance T2, is provided with a contact o, insulated from the other parts,
which is connected through y with the relay d; at the other end the relay dis
connected to the contact 16. In the position of rest of the key T2, the contact o
is drawn down to the contact p by means of a spring, whereby the contact 16 is
connected through the relay d with the earth. If, therefore, at the transmitting
station one of the cams b or c makes contact with the arms m, n a current from the
battery S¹ or S² passes through the line L to the axis B at the receiving station;
from B the current passes through m, n and g to the receivers R¹ R²-that is,
unless one of the cams has separated the arms m, n from the bar g. In the latter
event, the current passes through B, n, b (or c) U2 and 16 to the relay d; and
from there through y, and to earth. The local circuit - will thus be closed
which, by means of any suitable well-known apparatus, has the effect of retaining
the axis A, until the current passing to d is broken, that is, until at the transmit-

page_text: ting station the corresponding cam has left the arm m or n. The correct mutual
relation of the cams b, c at both stations is thus again reinstated. This adjustment
of the cams is maintained for a long time by reason of the uniform arrangement
of clockwork; but in the event of irregularity occurring, it is immediately cor-
rected in the manner just described.
The cam discs as shown in Fig. 1 may be replaced by the arrangement shown in
Fig. 2.
In the latter figure, 22 p¹ is a contact arm, which rotates very rapidly on the
axis p2, and is provided with a contact brush p³.
The hatching in Fig. 4 indicates an ebonite disc, covered by metal layers U³
U and B. The disc and metallic layers are stationary; the arm p² passes over
the surface of the disc and layers, its brush p³ making contact with the metallic
layers U3 U B¹ one after the other. The metallic leaves B₁ are in electrical con-
nection by means of a band-see dotted lines, Fig. 4. The other layers U³ U* are
in metallic connection neither with one another, nor with the layers 13.
In this arrangement, the layer U³ takes the place of the disc U₁ (Fig. 1);
and the place of the other disc U2 is taken by the second layer U4. The layers B¹
take the place of the cross bar g, the currents entering either operating the re-
ceiving apparatus R¹ R2, or going direct to earth. The main line is connected at
the axis p3.
The operation is the same as in Fig. 1. The difference consists solely in the
contacts in this fig. being made by the rotation of the discs, and in Fig. 4 by
the rotating arm. The remaining arrangements for the regulation of the motion
remain the same.
Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what I
claim is:-
1. The arrangement for transmitting telegraphic messages in contrary directions
simultaneously over a single wire, according to which at each station a similar
apparatus is placed, consisting of two cam discs (U₁ U²), rotating with isochronal
motion mounted on a non-conducting axis (A), in combination with friction
arms (m, n) secured to a rocking axis (B) and making contact with said cams,
and with a cross bar (g), in such manner that when the arms (m, n) are raised by
the cams (b, c) of the discs (U¹ U2), the circuit to one of the receivers is broken,
all substantially as set forth.
2. For the working of the arrangement claimed in Claim 1, the use of two pairs
of electromagnetic coils (7 and 8) consisting of polarised relays, the armatures
(4 and 5) of which are in equilibrium on their fulcrum (6) when no current is
passing, for the purpose of causing the various currents from various sounders to
operate only at the definite receiving station, all substantially as set forth.
3. In the arrangement claimed in Claim 1, the insertion in the system of a
relay (d or e) for prevention of simultaneous contact at both stations, substantially
as described.
4. In the arrangement claimed in Claim 1, the substitution for the rotating
discs (UU) and cross bar (9), of a rotating arm (2p) and metal layers UBU* B³)
on an ebonite plate, all substantially as set forth in reference to Fig. 4 of the
drawings.
D
1
14 of Wohnuomy 1898