Arrangement of Circuits and Apparatus to be used in connection with Telephonic Communication.
Year: 1889

page_text: Date of Application, 8th June, 1889
Complete Specification Left, 10th Mar., 1890-Accepted, 26th Apr., 1890
PROVISIONAL SPECIFICATION.
Arrangement of Circuits and Apparatus to be used in connection
with Telephonic Communication.
I, JOHN EDWARD KINGSBURY, of 79 Coleman Street, in the City of London,
Manager, (a communication to me from abroad by Francis Raymond Welles, of
Antwerp, Belgium, Manager,) do hereby declare the nature of this invention to be as
follows:
-
In telephone switch boards it is usual to make connection between two subscribers
by the use of a pair of plugs and cords with a clearing-out drop in circuit.
On such a plan, the subscriber's annunciator drops are cut out of circuit and the
clearing-out drop alone remains in. On some switch boards generally of small size
the clearing-out drop in the circuit of a pair of cords is omitted and both subscribers'
drops remain in circuit. Or by the use of two spring-jacks for each subscriber the
annunciator drops of the subscribers have been omitted at the will of the operator.
In my invention herein described I arrange the circuits and apparatus so that the
annunciator drop of one subscriber is cut out of the line and I use only one spring
jack for each subscriber.
The individual telephone lines are connected each with a single switch or spring-
jack on the switch board the circuit going first to the body of the jack and branching
therefrom through the indicator drop to the line spring of the jack thence to earth
through the earth contact of the spring-jack upon which the line spring rests when
the plug is not inserted.
The connection of two subscribers is made in the usual way by a pair of plugs
attached to a flexible cord or other electrical conductor. One of said plugs is of the
usual pattern the part inserted in the spring jack being entirely of metal so that
contact is made between the line spring which rests upon the point of the plug and
the body of the jack into which the plug is inserted. The other plug of the pair has
the part which comes in contact with the body of the jack when inserted insulated
from the point so that the body of the jack is not in contact with the line spring.
The indicator of one is therefore cut out of circuit whilst the indicator of the other
remains in circuit to signal the discontinuance of conversation or otherwise.
The spring jacks used in telephone switch boards I construct of strips of metal
insulated from each other two of which strips are attached to a small piece of tube
forming the front of the spring jack and into which the plug is inserted. The metal
strips and the insulating strips are bolted or otherwise held firmly together.
"
When used otherwise than in connection with the circuit before mentioned or for
metallic circuit systems, the two outer insulating strips are not required. I preferably
use 5 strips of flat metal for the purpose of obtaining greater rigidity in proportion to
the weight of metal used, for the advantage of double springs to grasp the point of
the plug and double contacts to the earth spring when the spring-jack is not engaged
but I may use a less number.
In the annunciator drop used in connection with telephone switchboards I form the
electro magnet.of a central core of soft iron, a helix of wire and a tube also of soft
iron. The external tube and the central core are magnetically connected and together
attract the armature to which is attached the pivot arm or catch releasing the indicator
shutter.
This arrangement increases the sensitiveness of the indicator and reduces the
electrical induction between neighbouring indicators.
Dated this 8th day of June 1889.

page_text: COMPLETE SPECIFICATION.
Arrangement of Circuits and Apparatus to be used in connection
with Telephonic Communication.
I. JOHN EDWARD KINGSBURY, of 79 Coleman Street in the City of London,
Manager, (a communication to me from abroad by Francis. Raymond Welles, of
Antwerp, Belgium, Manager) 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 :-
--
In telephone switch boards it is usual to make connection between two subscribers
by the use of a pair of plugs and cords with a clearing-out drop in circuit.
On such a plan, the subscribers annunciator drops are cut out of circuit and the
clearing-out drop alone remains in. On some switch-boards generally of small size
the clearing out drop in the circuit of a pair of cords is omitted and both subscriber's
drops remain in circuit. Or by the use of two spring-jacks for each subscriber the
annunciator drops of the subscribers have been omitted at the will of the operator. In
my invention herein described I arrange the circuits and apparatus so that the annun-
ciator drop of one subscriber is cut out of the line and I use only one spring jack for
each subscriber.
The individual telephone lines are connected each with a single switch or spring
jack on the switch board the circuit going first to the outer tube or body of the jack
and branching therefrom through the indicator drop to the line spring of the jack
thence to earth through the earth contact of the spring-jack upon which the line spring
rests when the plug is not inserted.
The connection of two subscribers is made in the usual way by a pair of plugs
attached to a flexible cord or other electrical conductor. One of said plugs is of the
usual pattern the part inserted in the spring jack being entirely of metal so that con-
tact is made between the line spring which rests upon the point of the plug and the
body of the jack into which the plug is inserted. The other plug of the pair has the
part which comes in contact with the body of the jack when inserted insulated from
the point so that the body of the jack is not in contact with the line spring. The
indicator of one is therefore cut out of circuit whilst the indicator of the other remains
in circuit to signal the discontinuance of conversation or otherwise.
The spring jacks used in telephone switch boards I construct of strips of metal
insulated from each other two of which strips are attached to a small piece of tube
forming the front of the spring jack and into which the plug is inserted. The metal
strips and the insulating strips are bolted or otherwise held firmly together.
I preferably use 5 strips of flat metal for the purpose of obtaining greater rigidity
in proportion to the weight of metal used, for the advantage of double springs to grasp
the point of the plug and double contacts to the earth spring when the spring-jack is
not engaged but I may use a less number.
When used otherwise than in connection with the circuit before mentioned or for
metallic circuit systems, the two outer insulating strips are not required.
Figure 1 is a sectional view of a spring-jack formed in the above manner.
Figure 2 is a plan view of the said spring-jack.
Figure 3 is a plan view of strip c of said spring-jack.
Figure 4 is a plan view of the strip bor d which are attached to the metal tube
and with it form the body of the spring-jack.
Figure 5 is an illustration of the ends of the two plugs.
Figure 6 is a diagram of the connections to one spring-jack.
Figure 7 is a diagram of the circuits employed and shewing two subscribers
connected.
Referring to figure 1 a b c d e are metal strips, ƒ ƒ ƒ fare insulating strips,
is a metal tube, the metal strips band d are soldered or otherwise securely attached
to and in electrical contact with g forming the body of the spring-jack, h is a screw
which passes through the strips and by means of the nut i holds them firmly together.

page_text: The strips & c and d are insulated at the point where the screw h passes through them
as shewn at ji in figures 3 and 4.
Figure 5 shews two plugs k and l. The plug k is entirely of metal from the
shoulder m to the tip n whilst the plug / has an insulated sleeve o from the shoulder m¹
to the point n'. One of the plugs is attached to one end of a short length of flexible
conductor the other plug to the opposite end.
In the diagrams Figures 6 and 7 the lines 1 and 2 represent wires coming from
two different subscribers.
On reference to Figure 6 it will be observed that a conductor p is led from each to
the metal strip 6 of one of the spring jacks and branches to one end of the coil of the
indicator 9 belonging to that spring jack and after passing through the indicator coil
proceeds to spring a thence through metal strip to earth, the strips a and c-being
then in connection as shewn. Thus a current can be sent from the line wire of any
subscriber through the annunciator coil used with that line wire. The annunciator
may be of any suitable description usually an ordinary drop shutter arrangement is
used.
The way in which a communication is made between line wire No. 1 and line
wire No. 2 when the two plugs klare inserted into the two spring jacks to which
these wires are coupled and the way in which only one annunciator is then left in the
circuit is shewn in figure 7.
g
When a plug is inserted through the tube 9 forming part of the body of the spring
jack the metal strips a and e are forced asunder by the tip of the plug and the contact
with c is broken. If the plug & be inserted into the spring jack of No. 2 wire its
tip will be in contact with strip a and the stem in contact with tube g and tube g
being as already described in electrical contact with strip b the strips a and b will
be short circuited and the annunciator drop 9 will be cut out and the current will pass
direct to the flexible conductor by which the two plugs are coupled. If the plug 7 be
inserted into the spring jack of No. 1. wire its insulated sleeve o will prevent electrical
contact being made with the tube g and only the tip of the plug will be electrically
connected with the spring a of the spring jack. There will then be no short circuit
between a and b and the annunciator drop will be left in circuit, the current being
conducted from the tip of the plug to a thence through coils to b and from 6 to
No. 1 line wire as shewn at Figure 7. In the circuit of the flexible conductor con-
necting the two plugs there may be placed speaking keys or switches of well known
construction by which the operator may as desired bring her telephone or ringing
apparatus into the circuit of either or both of the subscribers.lines.
In the annunciator drop used in connection with telephone switchboards I form
the electro magnet of a central core of soft iron, a helix of wire and a tube also of
soft iron. The external tube and the central core are magnetically connected and
together attract the armature to which is attached the pivot arm or catch releasing
the indicator shutter.
This arrangement increases the sensitiveness of the indicator and reduces the
electrical induction between neighbouring indicators.
Figure 8 is a plan view of an annunciator embodying my improvements.
Figure 9 is a vertical longitudinal central sectional view thereof.
Figure 10 is a front elevation thereof.
Figure 11 is a rear elevation as seen from line X-X of Figure 9.
Like parts are indicated by similar letters of reference throughout these different
figures.
A is the central core. B the helix of insulated conductor and C the external tube
surrounding the helix-the tube and core at one end are magnetically connected and
attached to a soft iron plate b by a screw * as shewn in Figure 9. D is the
armature hung opposite to the other end of the central core and tube on pivots e.
a is the lever arm which extends forwards from the armature through a slot
provided in the iron plate 6 the soft iron cylinder or shield C being cut away as shown
so as to give room.
The armature D is pivoted at pivots e above the rear end of the lever; very

page_text: slight movement of the armature and slight attractive force is the sufficient to
release the shutter so as to cause it to fall.
The frame or fork f is secured as shown to the shield C, its arms or prongs
extending backward and serving as a support for the block of rubber g upon which
are mounted the connecting pieces h i. The wires & forming the terminals or ends
of the helix are carried back through the armature D and connected as. shown
respectively with contact pieces and i. In this manner the terminals of the coils
are made accessible at the rear of the annunciator for connection with the circuit into
which the annunciator is to be introduced. This frame f may be niade conveniently
of brass. The pivots e may be inserted through the arms of this frame as shown.
The screw 6x is inserted from the front through the plate and the end of the soft
iron shield into the core; this single screw serving to hold the electro magnet of the
annunciator in proper position at the rear of the plate; while at the same time the
core is held in proper relation to the shield. By simply removing this screw any
electro magnet together with its armature and lever may be taken off for inspection
or repair.
Upon the front of the plate b and under each annunciator I mount a wire m, the
rubber pieces 丸 being secured to the plate and the wire being supported thereby
and insulated from the plate as shown.
When the shutter falls the local circuit closer o is brought into contact with the
wire m.
Annunciators thus constructed with a single coil are specially designed to be used
in close proximity, one to another, and are found to be more sensitive and reliable
and more convenient for connection of the wires than any heretofore used.
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 :-
:-
1. In circuit systems for a telephone exchange in which there is an annunciator
and one spring jack only for each line wire the construction of the circuits and
mechanism for connecting any two of the line wires in such manner that when any
two of the line wires are connected the annunciator of one wire only is left in the
circuit.
2. The combination with each line wire brought into a telephone exchange of a
spring jack having three blades or parts insulated from one another, one connected
to earth the two others connected to the two ends of an annunciator coil and one of
them connected to the line wire and to the body of the jack whilst the other normally
makes connection with the strip which is coupled to earth-and of a short length of
conductor with a plug or key at each end by one of which when any two line wires
are to be coupled the connection of one line with earth can be broken and connection
made between itself and the two blades or parts which are coupled to the two ends of
the annunciator coil-whilst by the other plug or key the earth connection of the other
line can be broken and connection made between itself and the blade or part
so moved away from the blade or part connected to earth-thereby leaving one
annunciator coil only in the circuit connecting the two line wires.
3. The combination in a telephone exchange of an indicator, a spring jack, and a
plug or pair of plugs, said indicator being connected in circuit between two points
of said spring jack normally insulated from each other, and said pair of plugs being
adapted one to short circuit the two points of one spring jack the other to leave the
two points of the other spring jack insulated the one from the other.
4. The combination with a flexible cord or other electrical conductor of a plug or
plugs at the ends thereof for insertion in spring jacks one of said plugs or one part
of said plug being adapted to connect the spring and the body of the spring jack
the other of said plugs or part of said plug by suitable insulation keeping the spring
insulated from the body of the spring jack.
5. The construction of the spring jacks substantially as herein before described and
illustrated in the drawing annexed.

page_text: 6. The construction of the electro magnets of annunciator drops used in con-
nection with telephone switchboards of a coil or helix surrounding a central core
and of an outer tube of soft iron surrounding the coil-the tube and core being
magnetically connected at one end and the armature hung on pivots opposite to the
other end.
7. The combination with the coil or helix of a soft iron shield surrounding the
same, the armature at the rear of the core of said helix and the armature lever
extending forward through a slot or opening in the plate and the drop with which
said lever is adapted to be engaged when the drop is lifted and to be disengaged
therefrom when the armature is attracted, substantially as and for the purpose
specified.
8. The combination with the coil or helix of a soft iron shield surrounding the same,
the armature at the rear of the core of said helix and the armature lever secured to
the armature below the pivotal support thereof and extending forward through a slot
or opening in the plate and the drop with which said lever is adapted to be engaged
when the drop is lifted and to be disengaged therefrom when the armature is
attracted, substantially as and for the purpose specified.
Dated this 7th love of March 1840