Improvements in Telephone Exchange Systems.
Year: 1893

page_text: Date of Application, 21st Feb., 1893
Complete Specification Left, 20th Nov., 1893-Accepted, 6th Jan., 1894
PROVISIONAL SPECIFICATION.
Improvements in Telephone Exchange Systems.
I, JOHN EDWARD KINGSBURY, of 79 Coleman Street, in the City of London,
Manager (a communication to me by The Western Electric Company of Chicago,
Illinois, United States of America) do hereby declare the nature of this invention
to be as follows:-
-
The improvements relate to telephone exchange systems in which the operating
coil of an annunciator is permanently connected from one limb of each line to the
other limb of the line in a closed bridge. With such a system when subscribers
are connected for conversation a number of such closed bridges exist at different
points according to the number of annunciators introduced into the circuit. These
closed bridges act as a shunt so as to weaken the voice currents that are being sent
over the line.
In the Specifications of former Patents granted to me Nos. 4427, 4428 and 4429
of 1892 I have described apparatus for telephone exchange switch boards in which
the respective connecting points for the line at each spring jack are permanent
branches of the respective limbs of the line and the annunciator employed is
composed mainly of two parts of which one termed the operating part is designed
to indicate a call over the line and the other termed the retaining part is designed
to restore the indicating mechanism on the insertion of a plug into the spring jack
by the operator and when restored to retain the indicating mechanism so that it
will not fall when a ringing current is sent over the line. The present improve-
ments are especially applicable to telephone exchange systems arranged in this
manner.
According to the present invention mechanism is provided for opening the
normally closed bridge in which the operating coil of the individual annunciator
is included and this mechanism is adapted to be actuated by current in a local
circuit which is closed when connection is made to the line; such mechanism may
be an electro magnet included in the said local circuit and provided with an
armature, actuating contacts included in the bridge with the annunciator. When.
an annunciator provided with a restoring magnet is employed the electro magnet
used may be the restoring magnet of the annunciator.
My invention will be more readily understood by reference to the accompanying
drawing.
In the drawing I have shown telephone lines extending from two subscriber's
stations to the central office, and each connected with a spring jack switch on each
of two switch boards. At each board is provided an operator's outfit in connection
with a single pair of plugs and cords. Thus station 1 is connected by line a with
the switches b c and includes the coil of the operating magnet d of the individual
annunciator. This coil d is in that portion of line a included between the two
springs or line terminals of switch c. The battery e is connected through the coil
of the restoring magnet and thence with the test pieces of said switches 6 c.
The tube of the switches is divided into two parts and the plug is provided with
contact points, one for each of the springs, and the other contact being in the form
of a sleeve serves to connect the two portions of the tube together. One portion
of each tube is connected to ground; thus, when a plug is inserted, battery e is
closed through coil of restoring magnet f in a well known way to bring the
armature of said magnet f back and hold the same in position as long as connection
remains with the line.
I do not deem it necessary to describe in detail the operator's outfit at each of

page_text: the boards. Suffice it to say that the operator's outfit and the manner of
receiving and answering a call, and connecting and disconnecting the line is illus-
trated in a manner well known and understood; in short, any of the well known
forms of operator's outfits adapted to do the work may be employed.
My invention relates to the opening the loop or shunt which contains the coil of
the main operating electro magnet of the individual annunciator. I have found
the most simple means of opening such loop to be to provide a key g, the spring
of which is forced away from the anvil or back stop thereof by the force of the
restoring magnet when energized. To this end I have provided an arm upon
the drop, which arm is forced against the spring of the key g to hold said key g
open as long as the drop remains closely held against the pole of electro magnet.
It will be understood that when this drop is simply retained by the hook connected
with the armature of lever d, it will be farther away from the pole of magnet f
lightly resting against the apron or target i. When in such slightly removed.
position, the key 9 will be closed, although the apron or target will not be pressed
against sufficiently to cause it to be held up to indicate a call signal.
Dated this 23rd day of January 1803
Improvements in Telephone Exchange Systems.
I, JOHN EDWARD KINGSBURY, of 79 Coleman Street, in the City of London,
Manager, (a communication to me by The Western Electric Company of Chicago,
Illinois, United States of America) 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 improvements relate to telephone exchange systems in which the operating
coil of an annunciator is permanently connected from one limb of each line to
the other limb of the line in a closed bridge. With such a system when subscribers
are connected for conversation a number of such closed bridges exist at different
points according to the number of annunciators introduced into the circuit. These
closed bridges act as a shunt so as to weaken the voice currents that are being sent
over the line.
In the Specifications of former Patents granted to me Nos. 4427, 4428, 4429
and 17160 of 1892 I have described apparatus for telephone exchange switch
boards in which the respective connecting points for the line at each spring jack
are permanent. branches of the respective limbs of the line and the annunciator
employed is composed mainly of two parts of which one termed the operating part
is designed to indicate a call over the line and the other termed the retaining part
is designed to restore the indicating mechanism on the insertion of a plug into the
spring jack by the operator and when restored to retain the indicating mechanism
so that it will not fall when a ringing current is sent over the line. The present
improvements are especially applicable to telephone exchange systems arranged in
this manner.
According to the present invention mechanism is provided for opening the
normally closed bridge in which the operating coil of the individual annunciator is
included and this mechanism is adapted to be actuated by current in a local circuit
which is closed when connection is made to the line; such mechanism may be an
electro magnet included in the said local circuit and provided with an armature
actuating contacts included in the bridge with the annunciator. When an annun-
ciator provided with a restoring magnet is employed the electro magnet used may be
the restoring magnet of the annunciator.
My invention will be more readily understood by reference to the accompanying
drawing.

page_text: The
In the drawing I have shown telephone lines extending from two subscriber's
stations to the central office, and each connected with a spring jack switch on each
of two switch boards. At each board is provided an operator's outfit in connection
with a single pair of plugs and cords. Thus station 1 is connected by line a with
the switches bc and includes the coil of the operating magnet d of the individual
annunciator. This coil d is in that portion of line a included between the two
springs or line terminals of switch c. The battery e is connected through the coil
of the restoring magnet and thence with the test pieces of said switches b c.
tube of the switches is divided into two parts and the plug is provided with contact
points, one for each of the springs, and the other contact being in the form of a
sleeve serves to connect the two portions of the tube together. One portion of
each tube is connected to ground; thus, when a plug is inserted, battery e is closed
through coil of restoring magnet fin a well known way to bring the armature of
said magnet back and hold the same in position as long as connection remains
with the line.
I do not deem it necessary to describe in detail the operator's outfit at each of
the boards. Suffice it to say that the operator's outfit and the manner of receiving
and answering a call, and connecting and disconnecting the line is illustrated in a
manner well known and understood; in short, any of the well known forms of
operator's outfits adapted to do the work may be employed.
My invention relates to the opening of the loop or shunt which contains the coil
of the main operating electromagnet of the individual annunciator. I have found
the most simple means of opening such loop to be to provide a key g, the spring of
which is forced away from the anvil or back stop thereof by the force of the
restoring magnet f when energized. To this end I have provided an arm upon
the drop, which arm h is forced against the spring of the key g to hold said key g
open as long as the drop remains closely held against the pole of electro
magnet. It will be understood that when this drop is simply retained by the
hook connected with the armature of lever d, it will be farther away from the pole
of magnet, lightly resting against the apron or target i. When in such slightly
removed position, the key g will be closed, although the apron or target will not be
pressed against sufficiently to cause it to be held up to indicate a call signal.
"
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:-
1. In a telephone exchange system, the combination with a telephone line circuit
and individual annunciator included in a bridge between the two sides of a line
circuit, of an electro magnetic device included with a source of electricity in a
local circuit adapted to be closed by the operation of connecting with the line, and
mechanism in connection with the said electro magnetic device for opening the
bridge containing the annunciator when said magnetic device is energized,
substantially as specified.
2. The combination with a telephone line of an individual annunciator consisting
of a main operating magnet and its armature and a restoring magnet and the armature
thereof acting as a drop, said drop being normally engaged by the armature lever
of the operating magnet and when so in engagement resting a short distance from
the pole of the restoring magnet and a key included in the circuit of the operating
magnet, said drop when attracted to its pole being adapted to open said key,
substantially as specified.
3. The combination with a telephone line extending from a substation to an
exchange, of spring jack switches with which the line is connected, an individual
annunciator included in a normally closed bridge circuit between the different sides
of the line upon each of the spring jacks, (like contacts of the different switches
belonging to the line being connected together), an electro magnet and a source of
electricity in a normally open local circuit of which the two groups of contact
pieces constitute the normally separated terminals, contact points in connection

page_text: with said electro magnet adapted to open the bridge wire containing the individual
annunciator when said magnet is energized and a connecting plug adapted for
insertion in one of the jacks, and arranged to cross together the said terminals of
the local circuit when so inserted, substantially as described.
Dated this 15th day of November 1893.
J. E. KINGSBURY.