Improvements in Telephone Switch Boards.
Year: 1898

page_text: Date of Application, 8th Oct., 1898-Accepted, 19th Nov., 1898
COMPLETE SPECIFICATION.
Improvements in Telephone Switch Boards.
I, FRIEDRICH MAX RICHTER, of No. 2, Adolf Strasse, Chemnitz, in the Kingdom
of Saxony, Empire of Germany, Manufacturer, do hereby declare the nature of
my said invention and in what manner the same is to be performed, to be particu-
larly described and ascertained in and by the following statement:―
This invention relates to telephone switch-boards, such as are used in the
exchange-stations of telephone-systems and its object is to provide means, whereby
the operator of the said station is enabled to restore each annunciator flap, when
fallen down after the call-release of a subscriber and in consequence a stop-signal-
ling, to its normal or operative position automatically by the act of inserting and
drawing out the respective switch-plug. The automatic action of the new device
therefore consists in lifting or returning and re-engaging the annunciator flap.
In the annexed drawing Figures 1, 2 & 3 show the improved switch-board device
in plan, sectional view and front view. According to the object of the invention
the front a of the switch board carries each plug receiving sleeve b and the respec-
tive annunciator-flap in juxtaposition, whereas the same commonly are super-
posed.
The hinge pin of the flap has a continuation, extending to the side of the plug
sleeve and passing through perforations formed at the lower part of such sleeve,
thus crossing from side to side thereof.
The portion of the said extended hinge-pin, lying within the lower part of the
sleeve, is provided with a lug e, having a horizontally projected part and a part
bent downwardly. The first named part of the lug e is set at a right angle to the
flap.c. The lower part of the sleeve is recessed to receive the lug so that the latter
can freely move, when the annunciator-flap falls or is raised.
The plug is to be used for switching the line-wire of a subscriber, when he
calls for connection and thus releases the flap, which also serves as the annunciator
in case of stop-signalling. The head of the plug f consists of a thick round metal-
rod f', which is tapered from a central point, the said metal-rod entering the plug-
shank and having connection with a flexible conductor through such shank.
Close to the shank or handle of the plug the tapered metal rod has mounted on it a
solid thick ring f2 formed of insulating material, the arrangement being such that
between the enlarged metal rod and the said ring a large annular space is formed.
The flexible conductor or conducting cord of the plug f is connected with another
plug g, adapted to be inserted in the switching device, if telephonic communica-
tion is wanted by the first named subscriber.
The plug consists of a thick metal rod, not provided with an annular space
such as f and not carrying a ring, like ring f2; this plug being solid throughout
from the end up to its shank or handle.
The front end of the plug-sleeve is fitted with a metal-ring h, having contact
directly with the line of the subscriber. The line is further connected with the
spool of the electromagnet k, the circuit from the other terminal wire thereof being
continued to the contact spring 1. The latter rests normally on the contact-

page_text: spring m, connected to the earth. By means of the armature n, under the control
of the electromagnet k, the annunciator flap is held in its vertical position. As
long as the plug f is not inserted in the switch device, the current passes from
the line of the subscribers station through the electromagnet and to the earth.
As soon as a subscriber uses the calling instrument, the annunciator flap c
falls down then the operator inserts the plug f in the sleeve b and raises the flap c
again by the thrust against the lug e, said flap being retained by the armature;
simultaneously the contact spring is lifted from the contact spring m. After the
plug is also inserted or connected with the device of the second subscriber
the circuit is completed as follows. From the wire i through the electromagnet to the
contact spring 7, thence along the plug f to the plug g, further through the metal-
neck of the same and the metal collar h to the wire of the subscriber.
After the telephonic conversation has been terminated the subscribers again
make contact for energising the electromagnet, thus again releasing the flap.
When the flap is down, the plug f is pulled out and it is the characteristic feature
of the invention that this action, by forcing the incline f4 against the lug e, the
flap is raised in the same way as it was raised previously by inserting the said plug.
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:-
:-
In a telephonic switch device for exchange switch boards, the combination of
a flap c and a plug f. and means in connection with both parts to raise the flap,
when down, both when the plug is inserted and when it is withdrawn, substantially
as described and shown in the drawing.
Dated this 8th day of October 1898
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.