Improvements in Telephone Switch Boards.
Year: 1899

page_text: Date of Application, 9th Mar., 1899-Accepted, 13th May, 1899
COMPLETE SPECIFICATION.
Improvements in Telephone Switch Boards.
I, JAMES MARTIN OVERSHINER, of Elwood, in the County of Madison and State
of Indiana, United States of America, Manufacturer, 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:-
My invention relates to improvements in telephone switch boards and more
particularly to the construction and arrangement of the switch and drop device,
one object of the invention being to so associate the switch and drop devices that
they can be quickly and easily operated by the attendant so that all the switch and
drop devices for each subscriber's line can be bodily attached to or removed from
the back or support and at the same time make or break the several electrical
connections between the switch and drop devices and the conductors on the back
or support.
A further object is to provide simple and efficient means whereby the drop can
be automatically restored to its normal position when the plug is inserted into the
jack and so that the act of withdrawing the plug from the jack will result in
returning the drop to its normal position after said drop shall have been made
to fall when a subscriber rings off."
With these objects in view, the invention consists in certain novel features
of construction and combinations and arrangements of parts as hereinafter set
forth and pointed out in the claims.
In the accompanying drawings, Figure 1 is a side elevation (with the back or
support in section) showing my improvements: Figure 2 is a longitudinal sectional
view Figure 3 is a bottom plan view. Figure 4 is a detail view of the plug.
Figure is a diagrammatical view. Figures 6 and 7 are detail views.
Figures 8, 9, 10 and 11 are views showing certain modifications.
A represents the back of the board which constitutes a support for the sets of
switch and drop devices for the various subscriber's lines. Each set of sub-
scriber's switch board devices is mounted in and supported by a frame B com-
prising end pieces 1-2 and connecting pieces 3. A jack is secured to the
respective end pieces 1-2 and the end piece 1 is made with a hole 5 to com-
municate with said jack for the accommodation of the plug to be inserted into
the latter. The forward end of the jack is made with a screw-threaded portion 7
which projects beyond the end piece 2 of the frame B and through the back or
support A.
An electro-magnet 8 is supported by the front piece of the frame B and
provided with an armature 10 from which a latch arm 11 projects forwardly and
terminates at its free end in a hook 12 adapted to engage an annunciator drop 13
and retain it normally in its elevated or closed position. The drop 13 is pivotally

page_text: supported at its lower edge and is provided on its outer face with a block or
projection 14 adapted, when the drop falls, to be disposed in proximity to the
entrance of the jack. The plug 15 hereinbefore alluded to, is provided with a
handle 16 which constitutes an engaging device to co-operate with the enlargement
on the drop. The handle 16 is made with an annular recess 17 having an annular
shoulder 18 at one end.
"
When the drop falls upon the calling by a subscriber, the insertion of plug
into the jack will cause the shoulder 18 to engage the block or enlargement 14
and restore the drop to its latch device. When the subscribers finish, with use
of the line and ring off," the drop will again fall and the block or enlargement
14 will become disposed in the recess 17 in the plug handle 16. As the plug is
now withdrawn from the jack by the operator, the shoulder 18 will engage the
block or enlargement and again restore the drop, so that when the plug shall have
been fully withdrawn the drop will be in engagement with its latch devices.
A contact spring 19 is secured at one end to one side of the jack and provided
at its free end with a lip 20 to engage a pin 21 electrically connected with one
terminal of the coil of magnet S. The other terminal of the magnet coil is
connected, by a conductor 22, with a spring finger 23 secured at one end in a
groove 24 made in the outer face of the end piece 2 of frame B.
Another contact spring 25 is secured at one end to jack at the side thereof
opposite the contact spring 19. Spring arms 26 and 27 are secured to the end
piece 2 of the frame Band, extending inwardly, pass in proximity to the respective
contact arms 19 and 25, the free ends of said spring arms 26-27 projecting
through slots in the front piece of frame A and being provided with buttons
or finger pieces 28 and 29 respectively. The spring arm 26 is electrically connected
with a spring finger 30 secured at one end in a groove in the end piece 2 and the
spring arm 27 is electrically connected with a spring finger 31 similarly located in
another groove in said end piece 2.
A. pin 32 is secured to the front piece I of frame B so as to receive the
drop when it falls, and this pin is electrically connected with a spring finger 33
attached to the end piece 2 in the same manner as above explained.
Another spring finger 34 is attached to the end piece 2 in the same manner as
above explained and is connected with the drop through the medium of a con-
ductor 35. A bell is included in the circuit of the drop, pin 32 and contact
fingers 83-84, so that when the drop falls the bell circuit will be closed and
the bell sounded.
The back or support A is provided with a series of conducting strips, a, b, c, d, e,
cach having a groove f for the reception of small projections f on the respective
contact fingers, said conducting strips being included in the various central office
circuits: the circuits of the operator's phone, the generator and the bell.
When the structure comprising the frame B, the jack, spring contact or switch
devices, is placed against the hack or support A, the various contact fingers will at
once make contact with the respective conducting strips and thus connect the
various devices in their proper circuits.
A nut will be screwed on the screw-
threaded end of the jack and as said nut is screwed home, the spring contact fingers
will be depressed and made to bear firmly at their free end against the conducting
strips on the back or support A and will also serve to tightly secure the structure
to said back or support. The screw threaded extension of the jack also serves
as a contact device for the subscriber's line wire and said line wire may be
connected thereto by means of a small plate gl and a screw h.
With my improvements, when a subscriber calls central office the annunciator
drop will fall. The operator will then insert a plug into the proper jack (restoring
the drop) and her thumb or finger will simultaneously engage the button 29 and
the same will be pressed toward the plug whereby to press the arm 27 into contact
with the spring 25 and thus cause the listening circuit to be closed through the
subscriber's line and operator's phone. This will enable the operator to ascertain
what subscriber is wanted. The operator will then release the button 29 and

page_text: permit the listening circuit to be again opened. She will then insert the plug at
the other end of the conducting cord, into the jack of the subscriber's line wanted
and at the same time press the button 28 toward the plug so as to press the armi 26
into contact with the spring 19 and thus close the circuit through the line of the
subscriber being called and the generator in the central office.
When the operator presses the button 28 the circuit of the drop magnet will be
opened so as not to allow the latch of the drop to vibrate or drop to fall while the
subscriber is being called. As soon as the subscriber shall have been called, the
operator will release the button 28 and thus permit the signal circuit to be again
opened and the magnet circuit closed. When the subscriber's ring off," the
drops will again fall and the blocks or enlargements become disposed in the
recesses 17 of the plug handles. The operator will now withdraw the plugs and
in the act of so doing will restore the drops as herein before explained.
It will be seen that by means of my improvements, the operator is enabled to
ascertain the number of the subscriber wanted, call such subscriber and connect
the two lines, by two movements, thus facilitating the work at the central office,
it being usually necessary for the operator to make at least four movements.
With the devices herein set forth, the operator inserts a plug and simultaneously
manipulates the listening circuit, and then inserts the other plug and simul-
taneously manipulates the signal circuit thus making but two movements.
In the form of the invention shown in Figures S, 9, 10 and 11 A represents a
frame, comprising end blocks a, b and connecting plates or strips c', all of which
are made, preferably, of hard rubber or other non-conducting material. A Jack
socket is secured within the lower portion of the frame A and made to com-
municate with a hole in the front end block al to permit the insertion of a switch
plug thereinto. A spring contact arm 2 is secured to the rear block of the
frame, alongside the jack socket and insulated therefrom. The spring 21 is provided
at its free end with a contact finger 3 and at a point between its ends, said spring
is made with a tooth or projection 4 adapted to normally bear against the walls of
a slot or recess 5' made in the jack. The rear end of the spring 21 is electrically
connected with a screw 6, by means of which latter the frame and parts supported
thereby are secured to the back or support of the board and to which screw the
subscriber's line wire is connected. Another contact spring is secured in the
frame A. so that its free end will terminate normally in proximity to the contact
finger 3 of spring 2, and the said contact spring is included in circuit with a
suitable generator for signalling purposes. A small lever 8 is pivotally supported
in a slot in the front block of the frame and provided with a thumb or
finger button 91 disposed to one side of the jack, the forward end of said lever being
made to terminate behind the block and between the jack and the contact
spring. Thus when the operator places a plug in the jack of the line of a
subscriber to be called, said plug will engage the tooth 4¹ on spring 21 and connect
the subscriber's line in circuit.
The operator will (while she still has hold of the handle of the plug), press the
button of lever S' with the thumb of her right hand and thus move the contact
finger of spring 21 into electrical contact with the spring 71, thereby closing the
signal circuit and simultaneously opening the circuit through the cord and line of
the calling subscriber by moving the spring away from the plug and jack
socket.
The core 10 of an electro-magnet 111, is secured to the front block a¹ of frame A¹
by means of a screw 12. The terminals of the coil of said magnet are connected
with contact points 131, 141 secured to the head of the magnet spool. Contact
plates 151, 16 are disposed against the inner face of block a¹ of frame A¹, so that
when the screw 121 is tightened, the magnet will be drawn toward the block a¹ and
the points 131, 14' brought intimately into electrical contact with the plates 151. 161
and thus connected the coil of the magnet in circuit. The plate 15 is connected
with a conductor 17' while the plate 16' is electrically connected with the jack

page_text: socket. From this arrangement it will be seen that when the plug inserted inte
the jack and the lever 8 moved as above explained to move the spring 21 away
from the jack and into contact with the spring 7, the electro-magnet will be open-
circuited while the signal circuit is closed and thus the drop which is controlled
by said magnet will not be released during the operation of signalling the
subscriber.
A bracket IS is secured to the rear end of the magnet and serves as a support
for a depending armature 191. A. latch arm 20¹ is secured to the upper end of the
armature and projects forwardly and beyond the block a of frame A terminating
in a hook 21 to engage the upper end of the annunciator drop 221, said drop being
hinged at its lower edge at a point in proximity to the jack socket, preferably above
the same.
The hinge pin of the drop is preferably provided at its respective ends with toes
or cranks 23 which, when the drop falls, will be turned upwardly as the hinge
pin rocks, into electrical contact with conductors 24', 24' which are included in
circuit with a night bell.
The drop 221 is provided on its outer face, at its lower edge, with a cam or
enlargement 24 to be engaged by the end of an arm 25, the latter being pivotally
supported by the jack and adapted to project through an opening in the block
of frame A The pivoted arm 25' is provided at a point between its ends with a
curved enlargement 26' adapted to depend through a hole 27' in the top of the jack
so as to be engaged by the plug 28 when the latter is inserted into the jack. The
plug 281, it will be observed, is made with a rounded end although this is not
essential. The said plug is also made with a recess 291 preferably having its
forward face 301 beveled or curved as shown in Figure 10, and this recess is an
important feature of my invention.
The weight of the arm 25 will maintain the enlargement 26 normally in the
hole in the jack so that it will be in the path of the plug when the latter is inserted
into the jack. When a subscriber calls and the drop falls, the enlargement or
cam 24 will rest upon the arm 25. As the operator inserts the plug into the
jack, the end of said plug will engage the enlargement 26 on arm 25 and thus
raise said arm which; acting upon or pressing against the cam or enlargement 26.
will raise the drop and restore it to its latch device. When the plug shall bave
been fully inserted into the jack, the recess in the plug will be in line with the
hole 27 in the jack, so that the arm 251 will be permitted to fall to its normal
position, the enlargement on said arm entering the recess in the plug. Now when
the subscribers" ring off," the drop can again fall fall while the plug is in the
jack. When the operator withdraws the plug from the jack, the face 30' of the
recess 291 in said plug, will engage the enlargement 26¹ on the arm 25¹ and again
raise said arm, resulting in restoring the drop by cooperation with the can or
enlargement thereon as above explained.
Having now particularly described and ascertained the nature of this said
invention, and in what manner the same is to be performed, I declare that what
I claim is:
1st. The combination with a jack and a drop, of a plug to enter the jack and an
engaging device on the plug adapted to cooperate with the drop to restore it as the
plug is inserted into the jack and also while it is being withdrawn therefrom.
substantially as set.forth.
2nd. The combination with a jack and a drop in proximity thereto, of a pro-
jection on said drop and a plug having an engaging device thereon adapted to
restore tlie drop by engagement with the projection thereon when the plug is
inserted into the jack, and also when the plug is being withdrawn from the jack.
3rd. The combination with a jack and a drop having a projection thereon, of a
plug to enter the jack, said plug having an engaging. device to cooperate with the
projection on the drop whereby to restore the latter, said plug having a recess in.

page_text: rear of said engaging device to receive the projection on the drop when the drop
is down and the plug is in the jack, substantially as set forth.
4th. The combination with a support and a series of conductors thereon, of a
structure comprising a frame and the switch and drop devices of a subscriber's line.
a series of spring fingers secured to said frame and electrically connected with
said switch and drop devices, and a fastening device engaging said support and said
structure whereby to support said structure and cause the spring fingers to be
pressed against said conducting strips, said fastening device also forming a contact
device for a subscriber's line, substantially as set forth.
5th. The gambination with a support and a series of conductors thereon, of a
structure comprising, a frame and switch and drop devices of a subscriber's line,
said frame having grooves in one end, a series of spring fingers secured in said
grooves and electrically connected with said switch and drop devices, and a
fastening device engaging the frame and back and electrically connected with the
jack of the switch devices, said fastening device constructed to hold the frame close
against the support and cause the spring fingers to press against the conducting
strips on the support, substantially as set forth.
6th. The combination with a support and conducting strips thereon having
grooves or depressions therein, of a structure comprising a frame and switch and
drop devices of a subscriber's line, a series of spring fingers, each secured at one end
to said frame, electrical connections between said spring fingers and said switch
and drop devices, projections on said spring fingers and adapted to enter the grooves
or depressions in said conductors, and a fastening device for securing the structure
to the support and causing the spring fingers to bear forcibly against said
conducting strips, substantially as set forth.
7th. The combination with a jack, a drop, a latch for the drop and an electro
magnet for controlling said latch. of contact arms secured to the respective sides
of the jacks, one of said contact arms being included in circuit with the coils of said
electro-magnet, a spring arm disposed near each side of the jack and having buttons
on their free ends, whereby to permit them to be forced against the contact arms;
one of said spring arms being included in a listening circuit and the other spring
arm being included in a signal circuit, said last mentioned spring arm being adapted
to move the cooperating contact art so as to open-circuit the magnet coil when the
signal circuit is closed.
Sth. The combination with an annunciator drop and a jack, of an arm intermediate
of the drop and jack and adapted to cooperate with the drop and a plug to
enter the jack and cooperate with the said arm, whereby to restore the drop.
substantially as set forth.
9th. The "combination with a drop and a jack, of an arm arranged to be
connected with the drop, and a plug to enter the jack and engage said arm to
restore the drop, substantially as set forth.
10th. The combination with a drop and a jack, of an arm adapted to be con-
nected with the drop, a portion of said arm to be disposed in the path of the plug
which enters the jack, and a plug to cooperate with said arm and restore the drop
when the plug is moved in the jack, substantially as set forth.
11th. The combination with a drop and a jack, of a plug to enter the jack
and having a recess, and an arm intermediate of the drop and jack and
adapted to cooperate with the recessed plug to restore the drop when the plug
is inserted into the jack and also when it is withdrawn therefrom, substantially
as set forth.
12th. The combination with a drop and a jack, of an arm adapted to be-com-
nected with the drop, a projection on said arm to enter the jack and a plug to be
inserted into the jack and engage said projection whereby to move the arin- and
restore the drop substantially as set forth.
con-
18th. The combination with a drop and a jack, of an arm adapted to be
neeted with the drop, a projection on said arm adapted to enter the jack and a
recessed plug adapted to enter the jack and move said arm when said plug.

page_text: is inserted into the jack and also when it is withdrawn therefrom, substantially
as set forth.
14th. The combination with a drop and a jack, of a projection on the drop,
an arm adapted to engage said projection, a projection on the arm to enter the
Jack and a plug to enter the jack and engage the projection on the arm, whereby
to move the latter and restore the drop, substantially as set forth.
15th. The combination with a drop and a jack, of a projection on the drop,
an arm intermediate of the drop and jack and adapted to cooperate with said
projection to restore the drop when said arm is moved in one direction, a projection
on the arm to enter the jack, and a plug to enter the jack and having a recess to
receive the projection on the arm, whereby the arm will be moved by the plug and
the drop restored when the plug is inserted into the jack and also when it is with-
drawn therefrom, substantially as set forth.
16th. The combination with a drop and a jack, the latter having a hole therein,
and a projection on the drop, of an arm or lever adapted to engage said projection.
a projection on the arm or lever adapted to enter the hole in the jack, and a recessed
plug adapted to enter the jack and cooperate with said projection on the arm or
lever, whereby to move the latter so as to restore the drop when the plug is
inserted into the jack and also when it is withdrawn therefrom, substantially as
set forth.
17th. The combination with a drop, a cam or projection thereon and a jack
having a hole in the wall thereof, of an arm or lever pivotally supported at one end
and having a projection to enter the hole in the wall of the jack, the free end of
said arm or lever being disposed to cooperate with the cam or projection on the
drop and a plug to enter the jack and having a recess to receive the projection on
the pivoted arm or lever, whereby when the plug is inserted into the jack it will
engage the projection on the pivoted arm or lever and restore the drop, then permit
the projection on the pivoted arm or lever to enter the recess in said plug and the
drop to fall, and then again move said pivoted arm or lever to restore the drop when
the plug is withdrawn from the jack, substantially as set forth.
18th. The combination with a jack socket, of a spring arm normally in contact
with said jack socket, a second spring normally out of contact with the first spring.
à pivoted lever in proximity to the jack socket and adapted to engage the first-
mentioned arm, whereby to move it away from the jack socket and into contact
with the second spring, substantially as and for the purpose set forth.
19th. The combination with a jack, and drop devices, of a contact spring
normally in contact with the jack, a second contact spring normally out of contact
with the first-mentioned contact spring, means for including the magnet of the
drop devices in circuit with the jack, and a lever in proximity to the jack and
adapted to move the first-mentioned spring away from the jack and into contact
with the second contact spring, substantially as set forth.
20th. The combination with a jack having a slot, and electro-magnetic drop
devices included in circuit with the jack, a contact spring having a projection to
enter the slot in the jack, a plug to enter the jack and engage the projection on
said contact spring, a second contact spring normally out of contact with the
first mentioned contact spring, and a pivoted lever adapted to engage the first-
mentioned contact spring and move it in contact with the second contact spring,
substantially as set forth.
21st. The combination with a frame comprising two blocks spaced apart, of
contact plates on one of said blocks, an electro-magnet, contact points on one end of
said magnet and connected with the terminals of the coil thereof, a screw passing
through the block and entering the magnet whereby to support the latter and press
the contact points on the magnet against the contact plates on the block, a drop
and a latch for said drop connected with the armature of said magnet, substantially
as set forth.
22nd. In a switchboard, the combination with a support and contact devices
attached thereto, of a series of structures, each structure comprising a frame and

page_text: Jack, drop devices and cooperating contact devices corresponding to a single
subscriber's line supported by said frame and suitable fastening devices to
independently and removably secured each structure as a whole to the support
with the respective contacts in juxtaposition.
Dated this 9th day of March 1899
HERBERT HADDAN & Co..
18, Buckingham Street, Strand, London, W.C.,
Agents to Applicant.