Improvements in Apparatus for Telephonic Communication.
Year: 1891

page_text: Date of Application, 1st July, 1891-Accepted, 29th Aug., 1891
COMPLETE SPECIFICATION.
Improvements in Apparatus for Telephonic Communication.
We, JOSEPH SACK, Telegraph Superintendent, of No. 81, Rathenowerstrasse,
Berlin, N. W., EMIL VON MALTITZ and PETER ZIESEL, of the firm Von Maltitz
& Ziesel, Building Contractors, of No. 88, Hohenzollernweg, Cologne, in the
Empire of Germany, do hereby declare the nature of our invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
Our invention relates to an apparatus which, when employed in connection with
a telephonic system with a number of different stations, enables communication to
be established between any two of those stations independently, and in such a way,
that the remaining stations are completely disconnected and are consequently
unable to interrupt the conversation taking place between the two stations which
are in communication with one another, or to overhear the conversation which is
being interchanged between them.
To enable the nature of our invention to be more clearly understood, we refer to
the three sheets of drawings which accompany the present description and in
which
Fig. 3 a cross section,
Figs. 4 and 6-19 are detail views of the different appliances or mechanisms.
Sheet 4 contains diagrams showing the various paths or directions in which the
current passes.
The apparatus operates as follows:—
In order to close the circuit, the push button or key a is depressed, the wedge-
shaped pin in which it terminates acting on the armature d and the contact
spring b, the result being, that the latter is withdrawn from the platinum tip c¹ and
caused to come in contact with platinum tip c (see also Fig. 10).
As shown in the diagram Fig. 20 representing the general arrangement of the
circuit and in the diagram Fig. 22 representing the call-circuit, the current passes.
from the battery through the terminal B, contact piece c, spring, platinum
point o, spring m', and lever m to the terminal L', thence to the wire leading to
the various instruments, and then to the return wire or earth. In the case of the
other instruments included in the circuit, in which the platinum tip remains in
contact with the spring b, the current passes from the line or conduit through the
terminal L', lever m, spring m', platinum tipo and spring, to the platinum tip e',
thence through the electro-maguets d³ to the terminal L, and then passes to earth
or joins the return wire. In each station, the electro-magnet 3 is excited and
attracts its armature d. The armature d turns upon the pins or centres d², and is
withdrawn from the electro magnets (when they are inactive) by the spring f³
(Figs. 6-10) situated below the fulcrum of the armature.
The armature
carries a pin which is capable of movement in the toothed slot of the segment g.
On each occasion, that the armature makes a movement, the segment, owing to the
action of the spring f, moves forward one tooth (towards the left).
The effect of this arrangement is as follows:-
When the push at any station is depressed three times in succession, and the
circuit consequently closed three times, the armatures at all stations are attracted
by the corresponding magnets three times and are released three times, by which
means the segments at all stations are subjected to a forward movement
amounting to thrice the distance between two teeth.
On the spindle of the segment is fixed the disc provided with the platinum

page_text: tip which, when the disc assumes a certain position, comes in contact with the
contact spring or lever m³. The platinum tips hat the different stations are
arranged at different parts of the disc, in such a way, that when, for instance, the
push is depressed once, the platinum tip comes in contact.with the contact
spring in the first station, but when it is depressed twice, and the armature
correspondingly twice attracted, the contact between the spring m³ and the
platinum tip occurs at the second station only, and so on. (In this manner, as
may be easily seen, contact can be established with any one station independently
of the others.) (See diagram of circuit Fig. 23.)
We employ a clockwork mechanism as part of our apparatus, and we arrange it
in such a way, that it is immediately liberated when the segment g and the disc h
effect a movement. Consequently, the clockwork mechanism at all the stations
included in the system are set in motion simultaneously, as soon as contact has been
established at any one station, since the passage of the electric current at each of
these stations causes the armature there to be attracted and in consequence the
segment and the disc h to be moved forward.
The apparatus at the calling station is also liberated, when the push a is
depressed, for the pin a' with which it is connected is pressed against the
armature d, by which means the platinum tip & passes one or more teeth of the
segment g.
The segment g falls under the influence of the spring and causes the spindle and
the disc to revolve with it. The clockwork is now released by the disc, the
said disc having a notch which receives the tooth of the lever (Figs. 1, 4,
5 & 11-14 & 16-19). The latter is attached to the spindle which carries the
lever provided with a pawl kt. The pawl which is situated above the
escapement wheel provided with a pallet k, allows the said pallet or catch to move
in one direction, but prevents it from moving in the opposite direction. As the
pin is arranged at a convenient spot, the spring of the escapement wheel remains
in tension, when the pin is situated behind the pawl; consequently the
escapement wheel begins to move, as soon as pressure is communicated to it from
its spring by the depression of the lever and the corresponding elevation of the
lever arm .
This takes place on the disc being turned, since when this occurs, the tooth k¹
is pressed out of the notch, and the lever arms & ³ are consequently set in
motion. (Figs. 4, 5, 13, 18 & 19.)
The clockwork sets first in motion the contact lever m. After the lapse of a few
seconds, during which the push may be depressed once or several times (according
to the stations with which it is desired to communicate), the tooth of the disc
attached to the spindle breaks contact with the projection n of the lever m, the
latter being moved forward by the action of the spring p, until it comes in contact
with the platinum tip o. (Figs. 5, 13 & 14.)
In those stations, with which it is not desired to establish communication, the
contact lever m with the spring m² assumes a position of rest upon the platinum
tipo. By this means all the instruments are cut out, and a direct communication
is established between the line wires connected with the terminals L and L2, the
current then passing from the line through the terminal L', lever m, spring m²
platinum tip of to the terminal L² and thence into the return wire or to earth.
In the case, however, of the calling and receiving stations which are to be
connected, the telephone or the alarum is switched into circuit (Figs. 20 & 23).
That is to say, in the apparatus of the calling stations, when the push a is pressed
down, the lever 7 situated underneath the pins a' is also depressed. The lever 7 is
then held down by the pawl or tumbler in such a way, as to resist the action of
the spring. If now the tooth 12 of the disc ceases to be in contact with the
projection of the lever m, the prolongation m of the latter comes in contact
with the lever 7, and is thereby held in such a position, that it can neither move
forward with the spring m¹ to the platinum tip o, nor with the spring m² to the
platinum tip o'. .(Fig..13.)

page_text: The current thereupon passes through the levers m and q (Fig. 23), which latter
is connected with the terminal T, and through the telephone or the alarum to the
earth or the return wire.
At the station which has been called, the platinum tip 4', as already pointed out,
assumes a position such, that the contact spring on the contact lever m meets
the platinum tip ', when the movement occurs, by which means the lever m is
caused to assume such a position, that it can touch with the spring m¹ m² neither
the platinum tip o nor the tip
As now the disc is connected with the terminal T, the arriving current passes
through the lever m, the spring m³, platinum tip disc h and terminal T, to the
telephone or alarum.
The contact between the levers m and 7, or between the spring m³ and the
platinum tip ', takes place, after the clockwork mechanism has been a short time
in operation. The circuit for ringing up or communicating with the next
station (battery or induction current), or for the receiving telephone is closed as
follows:-
From the calling station, of which the telephone or battery push has been
pressed, or the inductor has been turned, to the terminal T, lever 7, prolongation m',
and terminal L into the line wire to the station which has been called, and then
through the terminal L', lever m, spring m³, projection ', disc h, terminal T to the
telephone T and here over the telephone lever to the alarum, or, when the
telephone is detached, to the latter itself, then to the terminal L² to the return wire
or to earth.
I
The backward movement of the toothed segment g and the disc h takes place by
means of the projection (see specially Figs. 1, 3 & 16-19) which forces back
the levers provided with the projection s¹ and kept in position by the spring s².
This action of, however, only takes place, after the disc and the spindle have
revolved. By this means the lever v is moved in the same direction, since it
is attached to the levers by means of the connecting piece »'.
The lever »
carries the platinum tip g, which on moving engages with the projection, by
which means the latter is slowly caused to revolve and to leave the position
shown in Fig. 18. The pin d' of the armature opposes no resistance to the back-
ward movement of the segment, since the teeth of the latter are highly bevelled
on the one side (Figs. 2, 9 & 10), the effect being, that they move the pin
sideways to-and-fro. The toothed segment having been moved backwards, the
clockwork is again held fast or arrested. In company with the toothed segment g,
the disc h attached to the spindle of the latter, is brought back to its original
position, the result being, that the tooth k¹ of the lever arm & is enabled to fall
into the notch. It follows, that the pawl / attached to the lever arm k³ thereupon
falls on the escapement wheel and holds it fast. In order to prevent the clock-
work from being arrested, before the projection t' of the disc t has assumed its
original position (Fig. 16) and the projection of the disc t has passed by the
projections of the lever s, the spindle or pivot (for the levers k and k³) has a
special lever arm attached to it, which in front forms a hook w. The pin t
engages with this hook, as soon as it has been forced from its normal position by
the projection t¹ (Figs. 18 & 19), and returns the lever w in such a position, that
the lever arm ³ remains raised, (which would also be the case) when the notch
As
in the disc is in such a position as would allow the tooth k' to fall into it.
soon as the projection t¹ ceases to be in contact with the lever, causing it to be
drawn back again by the springs 82, the lever v regains its normal position, and
the pin parts company with the hook we', enabling the heavier lever-as in ³-
to fall. The lever y assumes its normal position shortly before or at the same
time as does the seginent g, since the projection n' situated upon axle or spindle
(Figs. 1, 4, 5 & 11-14) comes in contact with the pallet n³ of the arm g, before
the disc has completed a revolution, and by means of the hook restrains the latter
from coming in contact with the pin g³, the result being that the spring * brings
the lever g into its normal position.

page_text: If it be desired, that the armature of the receiving station shall not be actuated
directly by the battery or by induced current, but on the contrary by means of a
local current, a special arrangement of contacts is employed, together with a local
battery, for which purpose the telephone battery may also be made use of.
This consists of the spring u, with the insulated projection and the contact
screws u² (Figs. 1, 3-5, & 11-13). The pin is inserted into the disc at the proper
place, which, after the apparatus has been for a short time at work, presses the
spring against the contact screw a², and so keeps the alarum circuit closed for
about 10 seconds.
The local current passes as follows (Fig. 21):
From the battery to the terminal, the spring u, the contact screw ², the
terminal L, the lever m, the spring m³, the tooth the disc, and the terminal T;
to the armature and so back to the battery.
We may also introduce an arrangement, by means of which it may be seen,
when the clockwork mechanism in any apparatus has run down, in which case the
apparatus is automatically cut out, so that the current passes to the next
apparatus, or, in the case of the last apparatus, to the return wire or the earth.
In the diagrams shown on Sheet IV.,
Fig. 20 represents the general arrangement of the circuit,
Fig. 21 the arrangement of the station which has been called, with automatic
call signal.
Fig. 22 indicates the course of the current during the call signal.
Fig. 23 indicates the course of the current after a station has been called.
In this figure, A represents the calling station, C a disconnected station,
(switched out of circuit) and D the station which has been called.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is:
In telephonic systems or lines having several speaking stations:
1. The arrangement of lever m having contacts m', m², m³, m³ in connection with
the contact devices o, o', ', said lever being controlled by the clockworks and the
keys in such a manner, that, according to the motion of a clockwork and the
depression of a key a, the said lever touches the said contact devices o, o', h', or q
to enable the operator either to give contact to all instruments or to switch them
into the through position or into the speaking position.
2. The arrangement of the key a carrying a pin a', in connection with lever 7,
pallet ', contact spring b, and contacts c, c', the said key being adapted to press the
lever downward into the contact position, so that it is held by the pallet q', and
at the same time to release the spring from the contact e¹ and to press it against
the contact c, so that the current is conducted through the electro magnet, that
the armatures at all stations are attracted, and the toothed segments are set in
motion.
3. The arrangement of the contact spring and contact pin ², in combination
with a tooth or a pin on the shaft of the going work, in order to close a local
circuit and thereby to ring up the respective stations, when the tooth 12 on, the said
going work shaft has placed the spring m into contact with the pin o
4. The arrangement of the projection or tooth a' on the shaft of the going work,
in such a manner, as to release the pawl q after a revolution of the said shaft, so
that the contact lever resumes its normal position.
5. The device for replacing the segment 7 into its starting position and for inter-
rupting the motion of the going work, comprising a tooth on the going work
shaft, and levers s, v, set in motion by the said tooth in such a manner, that the
pin places the segment lever carrying the tooth into the normal position,
whereby at the same time the recess in the disc of the segment lever axle is
placed underneath the tooth k¹ of the lever k, k³, so that the latter may drop with
its pawl ¿ªupon the escapement wheel, and hold the latter, provided that the

page_text: nose has passed the tooth s¹ of the lever s, so that the pin 2 of the lever v
connected with has emerged from the hook of the lever w fixed on the shaft of
the lever k, k³.
The whole substantially as described and for the purposes specified.
Dated this 30th day of June 1891.