Improvements in Apparatus for Telephonic Communication.
Year: 1888

page_text: Date of Application, 29th Oct., 1888
Complete Specification Left, 11th May, 1889-Accepted, 14th Sept., 1889
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Telephonic Communication.
I, JOSEPH SACK, Superintendent of. telegraphs, of Düsseldorf, Germany, do
hereby declare the nature of my invention to be as follows
1
My invention relates to apparatus employed in intermediate stations and has for its
principal object to automatically connect again the branches of a telephone conduit
which had to be separated during a conversation. For this purpose I combine with
the telephone lever a switch in the following manner.
The said switch comprises a pair of brass plates placed parallel to each other on a
vertical base plate or switch board near the right and left hand edge of the same and
provided with a pair of binding screws. Along the lower edge of the base plate and
at right angles to the said brass plates are mounted a pair of brass strips pivoted
near their outer ends on a pair of pins and cut off obliquely towards their inner ends,
that is towards the vertical centre line of the base plate. A pair of upright helical
springs, connected with the said oblique brass strips, press the latter constantly
against a pair of brass pins projecting from the base-plate.
The switch lever
placed vertically in the centre of the switch board and pivoted
at its upper end to a metal block lined right and left with strips of ebonite. To the
latter are attached a pair of steel springs connected electrically with each other and
with the earth, and pressing with their lower ends on the right and left side of the
switch lever, so as to prevent the accidental motion of the latter.
The telephone lever comprises, as usual, three brass plates. The first plate supports
a brass block which serves as a bearing to the double armed hook-lever, the hook of
the latter serving to suspend the telephone. The motion of the hook-lever is limited
by a pair of contact screws, one of which is fixed in a brass stand mounted on the
third of the three brass plates mentioned above, while the other is fixed in a small
brass post screwed into the second plate.
The forearm of the telephone lever carries a steel block, the sides of which converge
upward, and which passes through an equally converging recess in the base of the
switch-lever, for which purpose the telephone lever and the switch-lever are situated
perpendicularly one over the other.
The said steel block must have such a length, that, when the telephone is suspended
froin the hook-lever, the upper edge of the same will be situated from 0.5 to
1 millimeter below the lower edge of the switch-lever.
If now the switch lever is turned to the left, a short stud attached to the same
slides on the oblique upper face of the brass strip pivoted to the left side of the base-
plate, until the left-hand retaining spring forms metallic contact with the corresponding
stop-pin mentioned above (the opposite side of the spring carrying an insulating
piece of ebonite which remains in contact with the switch lever).
If now the telephone. is taken off the hook, before the handle of the switch lever
has been released, the rear arm of the telephone lever descends upon the second
contact screw, while the forearm ascends together with the steel block. The latter
ascends in the recess of the base board of the switch and arrives behind the switch
lever, which is consequently held fast in the position imparted to it by the hand and
remains in this position (resting against the left hand stop pin) until the forearm is
again lowered by suspending the telephone, and thereby the steel block removed
from the switch lever. The latter, being again released, is pressed back into its
middle position by the left hand steel-spring. A corresponding action takes place,
if the switch arm is turned to the right and is to remain in contact with the right

page_text: The switch may be modified by attaching the two retaining springs to the switch
board, but insulated from the same, and mounting on the fulcrum of the switch lever,
but insulated from the same, a short auxiliary lever provided with a fork-shaped
sliding spring, the said auxiliary lever resting on a segmental brass plate when in its
middle position. Right and left of the said brass plate, are situated two other brass
plates similar to the first, upon which one arm or prong of the forked spring of the
auxiliary lever will rest, if turned to the right or to the left in such a manner, that
the other prong of the fork remains on the central brass plate.
To ensure, that the retaining spring will rest against the right or left hand stop-pin,
the switch lever is provided with a piece of ebonite laid across the same.
The switch may also be situated underneath the telephone lever, the latter being
in this case provided with a horizontal auxiliary lever carrying at its free end the
steel block mentioned above. The latter must pass accurately through the base board
of the switch, as mentioned above, and lie under the switch lever, when the switch is
in its position of rest.
The operation for establishing the normal connection of the conduit after the
conversation has ceased, is the same with this modified switch and telephone lever as
described above. The connections may be as follows:
One of the telephone wires is connected with the vertical brass plate situated
along the left edge of the switch board, and the other wire is connected with the
vertical brass plate at the right edge. The stop pins are connected with a galvanoscope
and an alarm. The switch lever is connected with the moveable part of the key;
one of the fixed contacts of the latter leads to the telephone and the other to the
battery. The insulated retaining springs are connected with each other and with the
earth.
To provide, that a call can be heard at the desired intermediate station only, I
employ an instrument constructed as follows:
The instrument comprises a tooth-wheel with which is connected a pointer sliding
over a contact piece. The contact pieces are so arranged, that at different intermediate
stations they are never touched simultaneously by the respective pointers, but always
one after the other. Consequently, any speaking station can only receive a call, if
the pointer rests on the corresponding contact piece.
The said tooth-wheel is under the influence of a spiral spring, which holds it in a
given position, from which it will be removed, as soon as an armature lever which
gears into the tooth wheel is attracted by an electro-magnet. In this event, the
tooth wheel moves forward one tooth, and is then held by a ratchet pawl, so that
every current advances the wheel one tooth, until it arrives at its terminal position
from which it is turned back into the starting position by the spiral spring. This
takes place because on arriving at its terminal position, a radial arm secured to the
wheel, pushes the ratchet pawl sideways, so as to release the wheel. To avoid that
the pawl commences to gear into the teeth too early, the latter are so arranged, that
they are lifted by the spiral spring slightly higher than the depth of the teeth. The
recess before the first tooth of the wheel is deep enough to ensure, that the ratchet
pawl, which is capable of pivoting laterally, is pressed back again into the teeth of
the wheel by an auxiliary spring. The vertical and horizontal motion of the pawl is
limited by stop pins or other suitable devices. To prevent the tooth-wheel from being
turned too far, a projection is applied which comes in contact with a stationary
post.
Dated this 29th day of October 1888.
FAIRFAX & WETTER,
433, Strand, London, Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in Apparatus for Telephonic Communication.
I, JOSEPH SACK, Superintendent of telegraphs, of Düsseldorf, Germany, do
hereby declare the nature of my invention and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement:
The improvements relate to telephonic circuits having several speaking stations.
Their object is to automatically replace into speaking position (or through-connection)
the branch conduits which had to be disconnected for the purpose of holding
conversations, to enable the speaking stations to be called separately without
disturbing the others, and to automatically and simultaneously replace into the zero-
position the appliances necessary for separate calling, at the different speaking
stations.
In the apparatus for intermediate stations, illustrated by Figs. 1 to 4, the two
branch lines, are connected with the two metal plates d, d as usual. Close to
these plates are situated the levers b, pivoted at 2 and drawn by springs, so as to
rest against the pins g, g. The latter are connected with each other by a conductor
into which is inserted the call bell. As long as the levers b, abut against the
pins g, g the two conducting wires 1, remain in electrical connection with each
other. But the connection may be broken by turning the lever a aside, because in
that case the lever or bis forced away from the pins g or g¹ by the stud a¹ of the
lever a which had not previously touched the levers 6, 61. Consequently, if for
instance the lever a is turned to the left, the current can no longer pass from the
lever into the pin g, instead of which the current now flows from the lever b into
the lever a, because its stud a' is in contact with the same.
This
The lever a is connected from its fulcrum with a conducting wire leading to the
telephone, so that the latter is now included in the circuit and capable of working in
the usual manner. To ensure, that the lever, after having placed its lateral position,
remains in the same, so that it cannot be replaced into the middle position by the
springs, the telephone lever c has been arranged in a special manner.
lever has its fulcrum at c¹ and so arranged that its front end will drop when the
telephone is hooked on. But as soon as the telephone is hooked off, the rear end
will descend, whereby the small post i mounted on the front part of the lever cand
tapered towards the top, is placed close to the side of the lever a (which has been
turned aside) and prevents the latter from returning into its mid-position (see Fig. 2).
If at the end of the conversation, the telephone is attached to the hook h the lever
descends with the post i, so as to place the latter again underneath the lever a; the
latter is then automatically replaced into its mid-position by the springs f, f, whereby
the apparatus is again set for through-connection (ready for speaking) as before.
The lever a is, of course, always turned to that side towards which the operator
wishes to speak. A galvanometer may be applied, so as to indicate from which side
the station has received a call. I have also provided, that during the conversation
with one side, the other branch conduit remains connected with the call bell, so that
any calls from the other side may be heard during the conversation. If for instance,
the lever a has been turned for conversation through the left conductor, the spring f
is in contact with the pin g, whereby the right hand line is connected with the call
bell. As already mentioned, the two pins g, g¹ are connected by a wire, which
includes the call bell, and by the contact of the spring with the pin g the current is
conducted to earth, because the springs are connected by a wire leading to
earth.
If now a current is sent from the right side, it passes through the pin gl, call bell,
ping and spring to the earth. Should the spring fail to rest against the pin, the
line to the earth would be broken and no call could be made. The lever a may also
be connected with the small auxiliary lever a² (Fig. 4) which is situated between the
two pins e, e. These pins are connected by conductors with the springs ff and

page_text: with each other, while the auxiliary lever a² is connected to earth. If now the
lever a is turned. to the left, as we have previously supposed, the auxiliary lever
meets the pin e¹ and the calling current instead of passing from the spring directly
to the earth, flows first through pin e¹ to e and then from the auxiliary lever a² which
is applied to lever a but insulated from the same, to the earth. The passage of the
current is illustrated by Fig. 8.
This switch is applicable also to telegraph purposes, and more particularly for the
establishment of intermediate stations in working circuits with a single Morse
apparatus. If the unused line is not to be connected with the call apparatus during
conversation, the construction may be simplified. The post on the lever a is made
slightly wedge-shaped, to ensure that the spring for f1 as well as the auxiliary
lever a² if employed, makes a good contact with the contact pins. The extension i
may be mounted on a separate lever which is connected with the telephone lever.
To provide, that the call is only heard at the desired intermediate station, I have
adapted the arrangement shown in Figs. 5 to 7. The brass pin, index hand or
similar device m connected with the toothwheel k meets during its revolution a
contact piece connected with the calling circuit, and as the wheel and the index are
connected with the local battery, the contact closes the call bell circuit. The contact
pieces are so arranged at the intermediate stations included in the same circuit, that
the index hands during their revolution, always touch the same one after the other,
thereby sounding the alarms on the intermediate stations never at the same time but
always consecutively. Consequently a speaking station receives a call only if the
pointer m meets the corresponding contact piece.
Around the axle of the wheel is coiled a spiral spring adapted to hold
the wheel in a given direction or position, from which it may be removed by the
armature o of the electro magnet. For this purpose the said armature gears into the
teeth of the wheel and propels. the same one tooth as soon as it is attracted by
current passing through. the electro magnet. This motion causes a brass pin or
pointer m on one of the intermediate stations to touch the corresponding contact
apparatus.
The wheel is held in every position by the ratchet pawl.
To replace the wheel into its starting position after a station has been called, I
have applied a clock work u provided with a wheel u and the pin w², which is held
by the nose of the pawl when the wheel is in its starting position. If the
armature o is attracted by an electric current, the first tooth will press the pawl
downward, whereby the pin u² is released and slowly turned round by the clock
work so that in the mean time at least that station can be called, which corresponds
to the last tooth of the wheel. When the wheel u has about finished its rotary
motion, the pin u² meets the nose of the pawl whereby the latter is released from
the teeth of the wheel, and the latter allowed to snap back under the influence of
the spring n.
The operation is of course the same at all speaking stations situated in the same
circuit. To prevent the wheel from returning beyond its starting position, I have
applied a projection t which comes in contact with the forked wheel holder t¹.
To prevent the pointer from making contact, if it is propelled rapidly, so that the
call is not heard at any other station than that desired, I employ as contact apparatus
a balance lever v, vl, Fig. 5 from the axle of which the wire leads to the alarm bell.
If the pointer m meets the balance lever, it will not make electrical contact, because
itself or the pointer is provided on the other side with an insulating layer. But if
the pointer or index remains on the spot, while the balance lever is reversed or
thrown over by its impact with the pointer, the former comes in contact with the
rear side of the latter, which is not insulated, and as the pointer is connected with
the local battery, as already mentioned, the contact closes the call bell circuit and
sets the call bell in action.
To ensure that the arm of the balance lever is always turned downward, it is
made slightly heavier than the shorter arm v which does not touch the pointer. To
obtain the desired effect between the balance lever , and the pointer or the teeth,.

page_text: the pointer is rendered adjustable. The apparatus may, however, be modified by
making the two arms equally long and causing them to come alternately into contact
with the pointer. Instead of a balance lever a lever w (Fig. 7) connected with a
pair of vanes (a wind wheel) by means of a toothed sector and provided with an
insulated nose w' which is lifted by the pointer and propels the wind wheel during its
downward motion, so that the down motion becomes slower, and that the lever
connected with the current, if the lever is rapidly moved forward, no longer meets.
the latter during the descent of the lever. On the other hand, if the pointer remains
in its position behind the nose, the lever will fall on the same, and the alarm or call-
bell circuit is closed. The small pinion on the axle of the wind wheel may lie loose
on the same and connected with a ratchet spring, so that the wind wheel can only be
propelled by the down motion of the lever, and not by its up motion. To prevent
the balance lever from making contact during the return of the spiral spring, it may
have a special shape. From the lever however, is suspended a small insulated
plate w adapted to come into contact with the nose to during the return of the
pointer.
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 ;-
In telephone lines with several stations,
1. On the movable telephone lever c, or on a lever controlled by the same, a steel
block or projection i, adapted to hold after the removal of the telephone the switch
arm a of a lever switch in a lateral position, thereby to place the intermediate
station out of the central into the end position, and to release the switch arm'a after
the conclusion of the conversation and the suspension of the telephone.
2. On a lever switch apparatus, the arrangement of the insulated steel springs j,j,
with or without the auxiliary lever a on the switch arm a, adapted to bring the
released switch arm a into its mid-position, to retain it in this position and thereby
to replace the intermediate station in the central position.
3. For the purpose of replacing the apparatus for the individual call into the
ordinary position or arrangement, the combination of the tooth wheel K (which is
turned round by the electro-magnet pin stages of one tooth) with the spring n adapted
to replace the wheel K in its position of rest after it has been released; also the
mechanism for releasing the wheel K, comprising the stud and the cam 2 on the
ratchet pawl and a clock-work with the wheel and pin u² (or similar device)
adapted to be released by the motion of the wheel K and, after the wheel ¹ has made
a given motion, to disengage the ratchet pawl by means of the pin u², so that the
wheel K can be replaced in its position of rest by the spring n.
4. For the purpose of the individual call, without molesting the other stations of
the same line, the application of the balance lever v, v¹ or of the lever w with wind
wheel and of a pointer m (on the wheel K) connected with the battery, the said
lever being connected with the call bell and placed in the path of the pointer m, but
prevented from making electrical contact by an insulating facing, until the lever w,
(or balance lever v, vl,) has been lifted again and allowed to fall, or until it has been
reversed, whereby the lever and the pointer (in case the latter has not travelled
further), come into contact, and the call is sent to the desired station only; the whole
substantially as described.
1
P
1000
JOSEPH SACK.
By Fairfax & Wetter,
433, Strand, London, Agents.