An Automatic Telephone Exchange, and Means relating thereto.
Year: 1898

page_text: Date of Application, 20th Dec., 1898-Accepted, 8th Apr., 1899
COMPLETE SPECIFICATION.
An Automatic Telephone Exchange, and Means relating thereto.
I, EDMUND PREISMANN, of No. 4, Griechische Strasse, Odessa, in the Empire of
Russia, Doctor of Medicine, do hereby declare the nature of this Invention and in
what manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement :-
This invention relates to an arrangement by which a subscriber of a telephone
exchange can connect himself with another subscriber automatically without the
assistance of attendants at the telephone exchange. According to this invention
an apparatus is provided for each subscriber at an exchange or central station which
is provided with contacts for the other subscribers. A certain number of impulse's
can be sent over two separate circuits from each telephone, according to the number
of the subscriber to be called up. Each circuit can act on an electric switching
device in such a manner that a contact pin can effect 2 movements at right angles
to each other, so that such contact pin shall occupy a position in which it switches
on, by the excitement of a separate electro-magnet,' the desired subscriber's line
and connects the same with the caller's telephone.
In order that this invention may be the better understood I now proceed to
describe the same with reference to the accompanying drawings and to the letters
and figures marked thereon.
Figure 1 is an elevation of the apparatus.
Figure 2 is a plan of the latter.
Figure 3 is an elevation seen in the direction of the arrow 3, Figure 2.
Figure 4 is an elevation seen in the direction of the arrow 4, Figure 1.
Figure 5 is an elevation seen in the direction of the arrow 5, Figure 1.
Figures 6 to 17 are detail views referred to in the following description.
Figure 18 is a diagrammatic view of the operation of the Invention.
The apparatus by means of which the subscribers' may connect themselves
automatically without the assistance of attendants at the telephone 'exchange is
constructed as follows.
r
A base a carries as fixtures standards b to bear axles c c¹, and standards d to bear
axles e e¹. If desired one axle would be sufficient for each of the movements which
take place at right angles to each other, but in the apparatus déscribed such axles
are arranged in pairs, to ensure greater perfection of the function of the apparatus
and exact movement and position of the contact pin.
In Figures 6 and 7 the axles are drawn to an enlarged scale, illustrating the
method in which a right and left handed return screw thread has been cut thereon.
Figure 7 shows an axle turned through an angle of 90° compared with Figure 6.
Each pair of the two pairs of axles acts in conjunction with a separate electro
magnetic arrangement, and as the same and connecting parts are alike in each
system it will be sufficient if the construction and function of one system, e², is
described; special reference is made to Figure 4, and detail views Figures 13
and 14.
"
Each excitement of the electro magnet e² by an electrical impulse attracts an
arinature e³ which transmits its motion by a lever e' to a clockwork pallet lever e³.

page_text: The lever moves a ratchet wheel step by step, for which purpose the pins es of
the lever e engage alternately with the teeth of the ratchet wheel'e. The lever e
is pivotted on a support e and, according to the position of the armature e³, which
is subjected to the action of a spring 12, either the one pin or the other of the pallet
lever engages with the wheel e which latter is operated only by the armature e³
on its recoil. A spur wheel e is situated on the same axle as the ratchet wheel e,
Figure 14, and engages with two smaller spur wheels e10, Figure 4, so that the
latter are rotated step by step according to the transmission of the electric current
and the excitement of the electro magnet e². As the wheels e10 are fixed to the
axles e, e¹, the two axles e and e¹ are rotated simultaneously, but in opposite
directions. The two axles c and care bridged by a piece or bridge f which
corresponds to the bridge g of the axles e e', Figure 10. Each of the axles c c' is
surrounded by a sleeve f³, corresponding to the sleeves, ³ of the axles e e¹ which are
connected by a second bridge g¹ to one another. The sleeves f³ and connecting
bridge are insulated from the bridge f, and are provided at each exle with a
rotating pin f2 with guiding pin or projection f¹, which engages in the thread of
the axle and is moved longitudinally during the rotation of the latter first from
one end of the axle to the other end and returns to the former end, though the axle
is continued to be rotated in one and the same direction, on account of the right
and left handed return screw thread, shown in Figures 6 and 7. The bridge f
and the contact pink join in the movement of the pins f2. A slotted rod f4,
Figs. 2 and 10, is also rigidly connected with the bridge f. Through the slot
thereof passes the contact pin k in the manner shown in Figures 10 and 11 and is
therefore carried by the bridge f in one direction. The other movement of the
contact pink which is at right angle to the before mentioned movement, is effected
by the axles e e¹ and the bridge g.
Each apparatus is designed for 100 subscribers according to the accompanying
drawings, but it will be obvious that each apparatus may be constructed for 1000
subscribers instead of for 100, or it may be constructed for any other number, it
being only necessary to provide the corresponding contact connections. By the
application of the before mentioned electro-magnetic devices, the contact pink can
be moved by the axles c, c¹ and e e¹ to be placed over one of the 100 contact pieces l.
To each of the latter corresponds a connecting screw m, which is connected to the
corresponding subscriber's line. The line of the subscriber for which the apparatus
is provided has no connecting screw m, so that the number of connecting screws m
is always one less than the number of subscribers for which the arrangement is
devised, because it is only necessary to provide for the connection of the subscriber
with the other subscribers, but not with himself.
When the contact pink has been brought into the required position by the
excitement of the electro magnets c² and e² the contact pin k must be depressed
in order to connect the required subscribers line with the line of the caller. For
this purpose an electro magnet i is excited, Figure 3, which then attracts an
armature which transmits its movement by means of a wire 12 or similar device
to a jointed parallelogram which consists of levers 3 and 4 pivotted at 16 and 17
respectively and connected to each other by a rod . When the armature ¹ is
attracted and the parts of the parallelogram are moved accordingly, the connecting
rod moves parallel to itself and occupies a lower position than before. During
this movement a piece is depressed and thereby rotates an axle 10 through a
certain angle. The axle 210 carries an arm Figure 11, which during its descent
caused by the rotation of the angle 10 carries with it a frame 12 on which is
arranged the contact pin k. When this contact pink has been depressed it makes
contact with the contact piece l, connected to the line with which connection is
required. As a separate circuit is required for the excitement of each of the two
electro magnetic systems c² and e², one of these circuits must also serve to
excite the electro magnet i when the contact pink has been moved into the required
position. This is effected by the following arrangement.

page_text: Before the axle e and e¹ respectively is rotated, the bridge a¹ occupies a position
in which, pressing against a spring ³, Figure 9, sheet 2, it brings a contact lever k³
into the position indicated by dotted lines so that one contact lever is connected to
connecting screws k¹. The current directed through the circuit must pass through
these connecting screws in order to operate the electro-magnetic arrangement
designed for the operation of the axles c c¹. Therefore, the latter can only be
rotated when the bridge gl occupies its first position and presses the contact
lever against the connecting screws k¹. When the contact pink has been
adjusted in one direction by the corresponding rotation of the axles c c¹ so that the
excitement of the electromagnets 2 is no longer required, the contact lever 15 can
then effect the closing of another circuit. This is effected as follows:-
-
As soon as the axles e e¹ are rotated to effect the second movement of the contact
pin k, the contact lever occupies the position shown in full lines in Figure 9, in
which position it connects together the two contacts ² 2 causing the subscriber's
line, which was previously in circuit through the contacts ¹¹ with the electro-
magnets c², to be connected in circuit with the electro-magnet i through said
contacts 22. Thus the caller can at will excite the electromagnet i by sending a
current along the line which was previously used to operate the electromagnets c²,
so long as the bridge g¹ does not press the contact lever into the position shewn
in dotted lines in Figure 9.
Therefore as soon as the second movement of the pink has been effected by
the rotation of the axles e e¹ the contact pink can be drawn down by the
excitement of the electro magnet in order to make the required connection.
In order to send the required number of pulsations from the telephone of the
subscriber who wishes to be connected, through the two separate circuits, a special
device has been designed for sending the current, illustrating by a plan in
Figure 15, Sheet III., the cover being removed) and by sectional views Figures 16
and 17 Sheet III. drawn on the lines x-x and y-y respectively of Figure 15.
The device is provided with a crank o by means of which an axle o¹ may be rotated
to the left or to the right. The axle o¹ carries an endless worm o² which engages with
two worm wheels 03 04 which it can therefor rotate simultaneously but in opposite
directions. With the worm wheels 03 o are connected loosely wheels 05 of by
spring pressed pawls o' and 08. These latter can either slide over the teeth of
ratchet wheels 09 010 or rotate the latter. When the ratchet wheel o is rotated,
the pawl o8 slides on the other ratchet wheel 010 and vice versa. Therefore when
the crank o is rotated, in one direction, one of the ratchet wheels is rotated, and
when the crank o is rotated in the opposite direction the other ratchet wheel is
rotated, together with the wheel of and wheel of respectively. Each of the two
ratchet wheels carries a number of equally distributed pins of which engage with
the curved serrations of a wheel 012 and can rotate the same tooth by tooth. Dials
carrying numbers are situated on the same axles respectively as the wheels 012;
and the numbers thereon can therefore be moved consecutively. The numbers
are arranged in two series one from 0-9 upwards and the other from 9-0
backwards. When the disc has been turned so far that the number 9 can be seen
through an opening in the cover, the cantact pin k is at the end of the axles.
When, now the rotation is continued the contact pin k returns gradually into its
original position and passes ultimately into zero position in which case a nought is
seen through the opening. It will be obvious that by the right handed and left
handed screw thread on the axle, the contact pink can be moved quicker than
would be the case otherwise. If the crank o is turned in one direction and the
wheel of is thus moved, contact is made as regards one circuit by means of a
contact piece 015 and the connecting block 017, as soon as the contact piece o¹ is
at the apex of a tooth of the wheel o¹5. When the crank o is turned in the
opposite direction, contact is made between contact pin o¹ and connecting
block 018. Therefore according as to whether the crank is turned in the one
direction or the other, one or the other circuit can be connected and an electric
pulsation sent therethrough.

page_text: In order to effect connection between subscribers, the following steps are taken'
reference being had to Figure 18, Sheet 4.
For the sake of clearness only four subscribers stations S1 S2 S3 S4 are illustrated
and assumed. If the apparatus S¹ is to be connected to the apparatus S³ the sub-
scriber of the apparatus S¹ first turns the crank o a certain number in one direction ;
the current passes then from the earth circuit E through battery 1 to circuit 2, 3, 4, 5,
and connecting screw 6 of the apparatus A¹ situated at the exchange or central
station, and returns to earth through connecting screw 7 and circuit 8. Between
the contact screws 6 and 7 is inserted the electric switch for the axles c c¹, so that
the contact pink is caused to make one of its movements. When then the crank o
is turned in the opposite direction, the contact pin k makes its second movement,
so that the current flows from battery 1 to apparatus A¹ through circuit 9, 10, 11, 12
through the second electro magnetic arrangement, through 7 and 8 back to earth.
When the contact pin k now occupies the required position a lasting contact is
made in the current transmitting device B¹, whereby the current passes during the
conversation from the battery 1 through circuit 3, 4 to the apparatus A¹ where it
excites the electro magnet i in the manner before described, and consequently
causes the contact pin k to make contact with the connecting screw of circuit 3.
When then the button 13 is depressed in station S¹, the current flows from
battery 12 through this button 13 and through the circuit 3, 4 and 14 to the contact
pin and to circuit 3, then through circuit 15, 16, 17, 18, 19 to the hook switch,
and as the receiver of station S³ is suspended from its support, it passes through
contact 20 to the bell 21 and back to earth. The bell 21 is thus rung and the
subscriber of station S³ takes the receiver off its hook. This has also been done in
station S¹, so that the microphone circuit is closed in both stations. In the
station S¹ the microphone circuit is closed from the local battery 22 through
microphone M¹, circuit 23, primary bobbin 24, circuit 25, hook switch and back to
battery 22; in station S³ the microphone circuit is closed in a similar manner.
When now a person speaks into the microphone M¹ the secondary coil 26 is
influenced correspondingly and the telephone circuit is closed through secondary
coil 26 telephone 27 circuit 28, 3, 4, 14 contact pin K circuit 3, 15, 16, 17, 18, 29
telephone 30 microphone coil 31 circuit 32 and back to earth. The subscribers of
apparatus S¹ and S³ can now converse together and interrupt the circuit by hanging
up their receivers.
Into the telephone circuit of each subscriber's circuit may be inserted a galvanoscope
which makes only a movement when connection has been made so that it can be seen
whether the desired connection has been made.
In the arrangement as described it is assumed that conversation takes only place
through a circuit. Of course the double circuits of each station may be used without
serious alterations in order to converse without earth circuit. In such case the
earth circuit will be used only for switching on the subscriber's. stations.
It should be noted that the number on the dials are of different colours, the
numbers arranged upwards being of a different colour from the numbers arranged
backwards so that it can be seen at the first glance whether the axles move the
contact pin forwards or backwards and further that arrangements may be made so
that the conversation between two subscribers cannot be tapped by a third party.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
-
1st. Telephone apparatus arranged so that the subscribers can connect them-
selves automatically in such a manner that in order to call up a subscriber a
number of electric impulses are sent from the calling station corresponding to the
number of the subscriber to be called up whereby a contact pin is moved by electro-
magnetic devices so as to come over a contact piece connected with the circuit of
the subscriber to be called, the said contact pin being then depressed by a separate
electro magnet in order to make the desired connection.

page_text: 2nd. A mode of construction of the arrangement claimed in Claim 1 in which an
apparatus is provided for each subscriber constructed so that two guiding pins
can be moved relatively to each other by a switching device receiving current
from a separate circuit by means of axles having right and left handed crossing
return screw threads in such a manner that a contact pin connected with the two
guiding pins makes two movements at right angles to each other in order to occupy
the required position for making the desired contact substantially as described.
3rd. A form of construction of the apparatus claimed in Claim 1 in which a
number of electric pulsations sent through a subscribers circuit pass through a
contact which is closed by a bridge gl situated in position of rest of the axle for
the second movement and the first mentioned contact alters its position upon the
movement of the contact pin by such sleeve and connects an electro magnet with
the first used circuit which electro magnet is excited when the contact pin has
moved into the desired position and depresses the contact pin until the conversation
has been finished substantially as described.
4. A form of construction of the apparatus claimed in Claim 1 having a jointed
parallelogram operated by an electro-magnet i in order to depress a contact pin k
the connecting rod 10 of such parallelogram moving parallel to itself and depressing
by means of an axle 10 the contact pink in any position of the latter substantially
as described.
በሰ፤ 1
1000