Improvements in and connected with Electric Bells.
Year: 1898

page_text: Date of Application, 7th Apr., 1893
Complete Specification Left, 13th Dec., 1893-Accepted, 1st Apr., 1899
PROVISIONAL SPECIFICATION.
Improvements in and connected with Electric Bells.
I. HERMANN OPPENHEIMER, Electrical Engineer, of 55, Redcross Street,
Barbican, London, E.C., do hereby declare the nature of this invention to be as
follows:-
-
It is a well-known fact that ordinary trembling bells can only be rationally
used up to a certain size on account of the necessity that the strokes should be
short, which difficulty is increasing with the size of the bell, requiring as it does
a large electrical source, and further that the arcing consequent upon heavy
current will quickly destroy the contacts. In order to overcome these obstacles,
it is necessary to construct larger sized bells in such a manner that the strokes
can be produced by means of weak currents, although the duration of such stroke
may be a prolonged one.
For this purpose I employ, a so-called tail hammer, which is lifted by means
of an electro-motor, and thrust either by gravity or by a spring, against the bell
dome. The lifting of the hammer, which is turning in the pivot and which may
be replaced by a fall or spring hammer of different form is executed during a
complete revolution of the snail which is fixed to the disc of the pulley. This
latter is started by means of a pinion of the armature spindle.
The armature is moving between the poles of the steel magnet, and receives
its current through two brushes sliding on the commutator.
In order to obtain a quicker movement of the hammer, the ratio between the
spindle of the armature, and the spindle of the pulley, can be altered, or one may
employ instead of one snail, several snail-shaped teeth, which naturally would
require an increase of current.
The employment of a motor-in connection with a fall or spring hammer allows
the production of wide strokes, which are essential to large sized bells of sub-
stantial thickness. It is also possible with these bells to produce single strokes
at certain intervals by directing the current to pass over a contact between the
roller and the snail (in which case obviously the snail and the roller would have
to be insulated from the pulley, and the hammer respectively, by means of bushes,
washers, made of ebonite, mica, or any other suitable insulating material) thus
causing with each stroke an interruption of the current. This automatic inter-
ruption of the current may however be fixed to any other moveable part of the
apparatus, and is not necessarily restricted to the manner in which I describe
it above.
The snail receives current by means of a spring, which slides on the pivot, and
such current passes to the plate, thence to the armature of the motor, and from
there to the terminal, while the roller is connected by means of a flexible cord
with the plate, and the other terminal of the battery.
An ordinary small bell is used as a means of control, such controlling bell
repeats single strokes of the motor bell by having its hammer attracted, when
the circuit is closed, and which is released for striking when the roller of the

page_text: motor bell leaves the furthest end of the snail. As soon as the roller touches the
springy lever, the current is closed again, and the armature of the controlling
bell is attracted.
Instead of using a bell as a means of control, a buzzer or a-galvanometer, an
indicator movement, or any other similar signalling apparatus may be inserted,
thus allowing to make sure from the point where the push is fixed, that the bell
at the further end has properly given the signals one wishes to transmit.
Dated this Chil
T
A 1000
Improvements in and connected with Electric Bells.
1, HERMANN OPPENHEIMER, Electrical Engineer, of 55, Redcross Street,
Barbican, in the City of London, 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:-
It is a well-known fact that ordinary trembling bells can only be rationally
used up to a certain size on account of the necessity that the strokes should be
short, which difficulty is increasing with the size of the bell, requiring as it does
a large electrical source, and further that the arcing consequent upon heavy
current will quickly destroy the contacts. In order to overcome these obstacles,
it is necessary to construct larger sized bells in such a manner that the strokes
can be produced by means of weak currents, although the duration of such stroke
may be a prolonged one.
For this purpose, I employ, as shown in Fig. 1 and 2, a so-called tail hammer,
which is lifted by means of an electric-motor, and thrust either by gravity or by a
spring, against the bell dome. The lifting of the hammer H which is turning
on the pivot D, and which may be replaced by a fall or spring hammer of different
form, is executed during a complete revolution of the snail S which is fixed to the
spindle of the cogged wheel Z. This latter is started by means of a pinion T of
the armature spindle with which it gears.
The armature A moves between the poles PP of the steel magnet M, and
receives its current through two brushes sliding on the commutator C (Fig. 2).
In order to obtain a quicker movement of the hammer, the ratio between the
pinion of the armature and the spindle of the cogged wheel, can be altered, or
one may employ instead of one snail, several snail-shaped pieces, which naturally
would require an increase of current.
The employment of a motor in connection with a fall or spring hammer, allows
the production of wide strokes, which are essential to large sized bells of sub-
stantial thickness. It is also possible with these bells to produce single strokes
at certain intervals by directing the current to pass over a contact between the
roller R and the snail S (in which case obviously the snail S and the roller R
would have to be insulated from the cogged wheel, and the hammer H respec-
tively, by means of bushes, washers, made of ebonite, mica, or any other suitable
insulating material) thus causing with each stroke an interruption of the current.
This automatic interruption of the current may however be fixed to any other
moveable part of the apparatus, and is not necessarily restricted to the manner
in which I describe it above. This alternative construction is only resorted to
when an indicating arrangement is used, as I describe in the second following
paragraph.
The snail receives current by means of a spring G, which slides on the pivot V,

page_text: and such current passes to the plate k, thence to the armature A of the motor,
and from there to the terminal K, while the roller R is connected by means of a
flexible cord U with the plate k. ., and the other terminal of the battery
marked K.
In Fig. 3, I show diagramatically an ordinary small bell Was a means of
control. Such controlling bell W repeats single strokes of the motor bell by
having its hammer attracted, when the circuit is closed, and which is released
for striking when the roller R of the motor bell leaves the furthest end of the
snail S. As soon as roller R touches the springy lever F, the current is closed
again, and the armature of the controlling bell is attracted.
Instead of using a bell as a means of control, a buzzer or galvanometer, an
indicator movement, or any other similar signalling apparatus may be inserted,
thus allowing to make sure from the point where the push is fixed, that the bell
at the further end has properly given the signals one wishes to transmit.
Having now particularly described and ascertained the nature of
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
my said
1. An electric bell actuated by an electro-motor with fall or spring hammer,
in the circuit of which a contact arrangement is inserted, interrupting automati-
cally the circuit after each stroke, substantially as and for the purpose specified.
2. An electric bell actuated by an electro-motor with fall or spring hammer,
in which the contact arrangement consists of an insulated moveable part of the
motor, and an insulated arm influenced by the hammer stem of the bell, substan-
tially as and for the purpose specified.
3. A motor bell with fall or spring hammer in which the moveable part of the
motor as claimed in Claim 2 is composed of a snail-shaped disc, or a number of
snail-shaped teeth, which are rotated from the axis of the electro-motor, and
which influence the arm of the hammer stem, substantially as and for the purpose
specified.
4. A motor bell with fall or spring hammer in the circuit of which a signal
apparatus may be inserted so as to control the actions of the movement, substan-
tially as and for the purpose specified.
Dated this 2nd day of December 1808