An Improved Means for Indicating the Duration of Conversations in Public Telephones.
Year: 1897

page_text: Date of Application, 22nd Nov., 1897
Complete Specification Left, 3rd Aug., 1898-Accepted, 10th Sept., 1898
PRUVIDIONAL SPECIFICATION.
An Improved Means for Indicating the Duration of Conversations
in Public Telephones.
We, ALFRED EWALD, of 61, Kastanien Allee, and MAX FRIEDLAENDER, of 12/13,
Molkenmarkt, both of Berlin, in the Empire of Germany, Merchant and Mechani-
cian, respectively, do hereby declare the nature of this invention to be as follows:-
This invention has for its object a counting or indicating device for ascertaining
the length of conversations in public telephones. This conversation indicator is
arranged in such a way that the registration of the conversation only takes place
from the moment when the desired connection is established, so that the person
calling up has not to pay for the time occupied in establishing connection with
the office and is also guarded against erroneous connections and has not to pay
for the loss of time caused thereby.
The arrangement of the conversation indicator according to the present inven-
tion is essentially as follows:-
If a person wishes to establish communication, he warns the office by means of
a signal bell. By this means a numbered flap drops at the office which switches
the current on to a contact of a circuit in which the indicating mechanism for
the subscriber called is connected. This circuit is then closed by the officials by
the insertion of a plug. An electro-magnet serves for operating the indicating
mechanism, said electro-magnet being excited at intervals which may be exactly
regulated by means of the pendulum of a clockwork or the like, which pendulum
alternately opens and closes a circuit.
The device employed which forms the actual object of the invention for operat-
ing the mechanism consists as follows:-
This
The electro-magnet attracts an armature at intervals corresponding to the move-
ment of the pendulum and thereby sets a pawl in an oscillating movement.
pawl rotates a cam wheel by means of gear wheels and the cam wheel raises a
toothed lever held against it by the action of a spring into the position in which
the said lever is arrested or retained by means of a bolt pushed forward by a
spring. By the raising or swinging to one side of the lever a wheel of a clock-
work of suitable construction is slowly operated by means of a pawl carried by
the end of said lever in such a way that this wheel only turns one tooth when
the cam wheel which has a ratchet form has raised or moved the lever to the full
height of a projection of the cam wheel. When the calling subscriber has not
obtained the desired connection in a given time, for instance in a minute (which
period of time is fixed as desired by the office and may be suitably adjusted or
altered by altering the length of the pendulum or weight of the pendulum), and
then rings off, an electro-magnet is excited by the circuit of the signal lever,
which electro-magnet revolves a double armed lever on its point of rotation in
such a way that the said lever presses back the spindle of the aforesaid cam
wheel and thereby releases a catch clutch or coupling of a suitable kind which
allows the cam wheel to spring back into its initial or zero position. The afore-
said toothed lever then also drops back and allows the indicating mechanism to

page_text: return to its initial position, the reading off of the indicating mechanisin being
assumed to be from the rear side as the double armed lever has simultaneously
drawn back the bolt. The bolt is connected with the double armed lever in such'
a way that it may be pressed forward by means of its spring without being pre-
vented by the said lever (which in this case may be drawn forward with it) and
may be pushed back by a thickened part of the toothed lever on the latter being
raised in consequence of its bevelled end without carrying the double armed
lever with it.
From the foregoing it is evident that the indicating mechanism which must
be arranged at the office for every subscriber separately only indicates when the
calling subscriber occupies the office for a longer time than the period fixed by it,
for instance a minute, as the pendulum movement is so adjusted that this period
of time is necessary to fully lift or swing the toothed lever and to turn the indicat-
ing mechanism one tooth further. If the correct connection is not obtained in
this time, the calling subscriber rings off and thereby causes the toothed lever
and also the indicating mechanism to again return to their initial positions. If
the correct connection is obtained within a minute or shorter time, the calling.
subscriber rings up the subscriber connected with him and thereby also causes
the indicating mechanism to return to the zero position, so that the duration of
the actual conversation is only counted from the establishment of a correct con-
nection.
The duration of the period allowed within which efforts can be made to establish
a correct connection without the indicating mechanism registering, may as already
mentioned be adjusted as required by adjusting the movement of the pendulum
and also the proportions of transfer of the gearing. Any worrying of the office
by a person ringing up during the conversation is impossible, as even if the cam
wheel returns to its initial position the official attending to the apparatus will
take hold of the bell of the connected subscriber as a closing signal and imme-
diately release the connection. The arrangement is such that the fastening bolt
when it springs forward for the purpose of stopping the toothed lever in its raised
or outward position breaks the circuit of the electro-magnet so that the mechanism
does not continue to work unnecessarily.
Dated this 20th day of November 1807
W. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicants.
An Improved Means for Indicating the Duration of Conversations
in Public Telephones.
We, ALFRED EWALD, of G1, Kastanien Allee, and MAX FRIEDLAENDER, of 12/13,
Molkenmarkt, both of Berlin, in the Empire of Germany, Merchant and Mechani-
cian, respectively, 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:―
This invention has for its object a counting or indicating device for ascertaining
the length of conversations in public telephones. This conversation indicator is
arranged in such a way that the registration of the conversation only takes place
from the moment when the desired connection is established, so that the person
calling up has not to pay for the time occupied in establishing connection with
the office and is also guarded against erroneous connections and has not to pay
for the loss of time caused thereby.

page_text: The arrangement of the conversation indicator according to the present inven-
tion is essentially as follows:-
If a person wishes to establish communication, he warns the office by means of
a signal bell. By this means a numbered flap drops at the office which switches
the current on to a contact of a circuit in which the indicating mechanism for
the subscriber called is connected. This circuit is then closed by the officials by
the insertion of a plug. An electro magnet serves for operating the indicating
mechanism, said electro-magnet being excited at intervals which may be exactly
regulated by means of the pendulum of a clockwork or the like, which pendulum
alternately opens and closes a circuit.
The device employed which forms the actual object of the invention for operat-
ing the mechanism is shown in the accompanying drawings,
Figure 1 being a front view;
Figure 2, a plan view; and
Figure 3, an end view, and consists as follows:-
The electro-magnet a attracts an armature bat intervals corresponding to the
movement of the pendulum and thereby sets a pawl e in an oscillating movement.
This pawl rotates a cam wheel 6 by means of gear wheels de and the cam wheel
raises a toothed lever g held against it by the action of a spring into the position
shown in dotted lines in which the said lever is arrested or retained by means
of a bolt h pushed forward by a spring. By the raising or swinging to one side
of the lever g a. wheel of a clockwork of suitable construction is slowly operated
by means of a pawl i carried by the end of said lever in such a way that this
wheel only turns one tooth when the cam wheel f which has a ratchet form has
raised or moved the lever g to the full height of a projection of the cam wheel.
When the calling subscriber has not obtained the desired connection in a given
time, for instance in a minute (which period of time is fixed as desired by the
office and may be suitably adjusted or altered by altering the length of the
pendulum or weight of the pendulum), and then rings off, an electro-magnet Z
is excited by the circuit of the signal lever, which electro-magnet revolves a
double armed lever m on its point of rotation n in such a way that the said lever
presses back the spindle of the aforesaid cam wheel and thereby releases a catch
clutch or coupling of a suitable kind (Figure 3) which allows the cam wheel
g then
to spring back into its initial or zero position. The aforesaid toothed lever
also drops back and allows the indicating mechanism to return to its initial
position, (the reading off of the indicating mechanism being assumed to be from
the rear side) as the double armed lever m has simultaneously drawn back the
bolt h. The bolt h is connected with the double armed lever m in such a way
that it may be pressed forward by means of its spring o in the direction indicated
by the arrow without being prevented by the said lever m (which in this case
may be drawn forward with it) and may be pushed back by a thickened part of
the toothed lever g on the latter being raised in consequence of its bevelled end
without carrying the double armed lever m with it.
Only those parts are shown in the drawing for the sake of clearness which are
necessary for understanding the invention. Similarly no plan of the course of
the current is shown as in practical working this affords no difficulty to an expert.
From the foregoing it is evident that the indicating mechanism which must
be arranged at the office for every subscriber separately only indicates when the
calling subscriber occupies the office for a longer time than the period fixed by
it, for instance a minute, as the pendulum movement is so adjusted that this
period of time is necessary to fully lift or swing the toothed lever g and to turn
the indicating mechanism one tooth further. If the correct connection is not
obtained in this time, the calling subscriber rings off and thereby causes the cam
disc f and also the indicating mechanism to again return to their initial positions.
If the correct connection is obtaned within a minute or shorter time, the calling
subscriber rings up the subscriber connected with him and thereby also causes
the indicating mechanism to return to the zero position so that the duration of

page_text: the actual conversation is only counted from the establishment of a correct con-
nection.
The duration of the period allowed within which efforts can be made to establish
a correct connection without the indicating mechanism registering, may as already
mentioned be adjusted as required by adjusting the movement of the pendulum
and also the proportions of transfer of the gearing de. Any worrying of the office
by a person ringing up during the conversation is impossible, as even if the cam
wheel returns to its initial position the official attending to the apparatus will
take hold of the bell of the connected subscriber as a closing signal and imme-
diately release the connection. The arrangement is such that the fastening bolt h
when it springs forward for the purpose of stopping the toothed lever g in its
raised or outward position breaks the circuit of the electro-magnet a so that the
mechanism does not continue to work unnecessarily.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:-
An improved means for indicating the duration of conversation in public tele-
phones, characterised by a circuit closed by the establishment of the desired con-
nection with the office exciting an electro-magnet at given intervals of time by
means of a pendulum contact, said electro-magnet imparting corresponding
armature oscillations through the medium of a cam disc and toothed lever to an
indicating mechanism in such a way that the latter is only turned one tooth for-
ward when the above mentioned toothed lever has been raised to the full height
of a cam, previous to which position the toothed lever of the apparatus is capable
of being returned to its initial position by exciting an electro-magnet inserted
in the circuit of the signalling device, and which electro-magnet disconnects the
cam disc from the toothed lever and thus allows it to spring back to its initial
position and simultaneously releases the locking bolt for the toothed lever, sub-
stantially as described and shown in the accompanying drawings.
Dated thin and 1
1900
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicants.