Improvements in or connected with Telephone Indicators or Annunciators.
Year: 1894

page_text: Date of Application, 9th Oct., 1894
Complete Specification Left, 22nd May, 1895-Accepted, 22nd June, 1895 *
1
PROVISIONAL SPECIFICATION.
Improvements in or connected with Telephone Indicators or
Annunciators.
I, LARS MAGNUS ERICSSON, of 5, Thulegatan, Stockholm, in the Kingdom of
Sweden, Manufacturer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to telephone indicators or annunciators having two magnet
coils, one for causing the flap to drop.and one for raising it.
According to my invention I arrange the annunciator so that the armature of
the restoring magnet-coil when attracted breaks a contact, whereby the other or
releasing coil is cut out of the circuit.
For this purpose I employ a sliding-bar which when the flap drops is acted upon
by the said flap, thereby closing the circuit of the signal mechanism by making
contact between two springs, a set-screw being situated in a line with the bar
whereby the motion of the bar can be limited and determined and the inclination of
the flap be regulated when falling.
The armature which serves to restore or lift the flap is arranged like a
bell-crank lever having one arm in engagement with the sliding-bar, which bar at
the attraction of the said armature of the restoring coil is caused to slide in the
opposite direction, thereby lifting the flap, and which armature by means of its
other arm breaks or makes another contact according as the armature is attracted
or not, thereby cutting out of or including in the circuit the magnet-coil serving to
let down the flap.
Dated this 9th day of October 1804
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
Improvements in or connected with Telephone Indicators or
Annunciators.
I, LARS MAGNUS ERICSSON, of 5, Thulegatan Stockholm, in the Kingdom of
Sweden, 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 :—
1
My invention relates to telephone indicators. or annunciators having two magnet
coils, one for causing the flap or indicating tablet to drop and one for raising it.
According to my invention I arrange the annunciator so that the armature of the
restoring magnet-coil when attracted by the insertion of a plug in the jack breaks
a contact, whereby the other or releasing coil is cut out of the circuit.
For this purpose I employ a sliding-bar which when the flap drops is acted upon
by the said flap, thereby closing the circuit, of the signal mechanism by making
contact between two springs, a set-screw being situated in a line with the bar

page_text: whereby the motion of the bar can be limited and determined and the inclination of
the flap be regulated when falling.
The armature which serves to restore or lift the flap is arranged like a
bell-crank lever having one arm in engagement with the sliding-bar, which bar at
the attraction of the said armature of the restoring coil is caused to slide in the
opposite direction, thereby lifting the flap, and which armature by means of its
other arm breaks or makes another contact according as the armature is attracted
or not, thereby cutting out of, or including, in, the circuit the magnet-coil serving
to let down the flap.
To enable my invention to be fully understood I will describe how it can be
carried into practice by reference to the accompanying drawing, in which:-
Figure 1 is a front end elevation of a telephone indicator or annunciator
constructed according to my invention :
Figure 2.is a longitudinal-section; and,
Figure 3 a rear end elevation of the same.
a is the flap or indicating tablet and is the magnet coil for releasing or letting
down the flap a. When the current passes through this coil, the iron core c is
magnetized and attracts the armature d, forming one arm of the bell crank lever
pivotted upon the pin e. The other arm f of the bell crank lever is terminated' by
a hook or detent which, on the attraction of the armature by the core, is lowered
and leaves the flap free. The flap then falls down by its own weight and lifts a
shutter or covering diso g. The flap a bears the indicating number. When the
flap has fallen down to a suitable inclination, adjusted according to the vertical
position of the flap mechanism, it is checked by the sliding bar . The degree of
inclination is regulated' by means of the screw .
71.
On the prolongation of the magnet core c is placed the lifting coil k. If a
current be passed through this coil, the armature will be magnetized and attract
the armature m, forming one arm of the bell crank lever pivotted upon the pin.
The armature m is at its lower end provided with a fork shaped prolongation o,
embracing the sliding bar between two collars ou the bar, so that the armature
can cause this bar to slide. On the other arm t of the bell crank lever is fixed
an ivory pin in such a mauner, that the pin is lowered upon the attraction of
the armature by the core, thereby breaking the contact between the spring s and
the screw 1.
As regards the outer conductors, the screws 2 and 6' are connected to the wires
from the line springs, the screws 3 aud 5 to the key springs and the screws 4 and 8
to the signal mechanism of an incandescent lamp or a bell.
The mechanism acts in the following manner. Upon a signal being given by a
subscriber, current passes through the screws 2 and 6 and through the magnet
coil b. The core then attracts the armaturo d, in consequence whereof the detent
is lowered and the flap a falls down, raising the disc g and disclosing the number.
When the flap falls down, the bar is caused to slide backwards, so that it makes
contact between the springs p and q and is checked or stopped by the adjusting
screw. In consequence of the contact between the springs p and q, the circuit is
closed and the signal, if desired, given in any suitable manner.
The attendant now takes the corresponding plug and inserts the same in the jack.
The key spring is thereby caused to make contact with the conductor from the
battery so that the key battery is closed through the scrows 3 and 5, and the coil k.
The iron core is then magnetized and attracts the armature m so that the pin." is
brought down and breaks contact between the spring and the screw 1,
consequently cutting out the coil b so that the latter is in connection with only one
'branch.
When the plug is removed from the jack after the conversation has ended the
current from the key battery is interrupted, the armature m'returns to its original
position and the pin is raised, so that contact is established between the spring s
and the screw 'l, whereby the coil is again included in the circuit.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what mauner the same is to be performed, I declare that what I
claim is :-
1. In a telephone indicator or annunciator having two magnet coils, one for
causing the flap or indicating tablet to drop and the other for raising it, an
arrangement whereby the armature of the restoring magnet-coil when attracted,
breaks a contact, whereby the other or releasing coil is cut out of the circuit
substantially as herein before described.
2. In a telephone indicator or annunciator a sliding bar which when the flap or
indicating tablet drops is acted upon by the said flap, thereby closing the circuit of
the signal mechanism by making contact between two springs in combination with a
set screw situated in a line with the bar and whereby the motion of the bar can be
limited and determined and the inclination of the flap be regulated when falling,
substantially as hereinbefore described and illustrated in the accompanying
drawing.
3. In a telephone indicator or annunciator an arrangement whereby the falling
flap or indicating tablet, when it has attained a suitable inclination, acts upon a
sliding part which by its motion, caused by the motion of the flap, makes contact
between two springs thereby closing the circuit of the signal mechanism
substantially as hereinbefore described and illustrated in the accompanying
drawing.
4. In a telephone indicator or annunciator a magnet coil serving to restore or
lift the flap or indicating tablet and having its armature arranged like a bell crank
lever having one arm in engagement with a sliding bar which on the falling down
of the flap is caused by this flap to slide, thereby closing the circuit of the signal
mechanism by means of a contact, which bar on the attraction of the said armature
of the restoring coil is caused to slide in the opposite direction, thereby lifting the
flap, and which armature by means of its other arm breaks or makes another
contact, according as the armature is attracted or not, thereby cutting out of, or
including in, the circuit the magnet coil serving to let down the flap, substantially
as hereinbefore described and illustrated in the accompanying drawing.
5. The improved telephone indicator or annunciator hereinbefore described and
illustrated in the accompanying drawing.
Dated the 22nd day of Mov 1805
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.