Improvements in Electric Bells.
Year: 1889

page_text: Date of Application, 16th Sept., 1889
Complete Specification Left, 16th June, 1890-Accepted, 26th July, 1890
PROVISIONAL SPECIFICATION.
Improvements in Electric Bells.
We, HARRISON GROVES, of 353 Strand, in the County of Middlesex, Merchant, and
JOSEPH HENRY STEWART, of 111 Ivanhoe Road, Denmark Park, in the County of
Surrey, Electrician, do hereby declare the nature of this invention to be as
follows:-
This invention has for its object improvements in electric bells.
6
Our improved electric bell is of the class commonly known as trembling bells"
in which the armature of an electro magnet carries the hammer which strikes upon
the bell and also a spring contact piece. These parts are so arranged that when
the armature is attracted the bell is struck and in the same movement the electric
circuit is opened. This opening of the circuit in which the magnet coils are
included permits the armature to fall back under the influence of a spring blade
by which it is carried. The movement is then repeated and continues so long as
the outside circuit is complete.
In these beils it is usual to employ two magnet bobbins placed horizontally; one
of these attracts the armature at a point near to its centre of motion and the other
at a point at a considerable distance from it. In these bells the length of the
armature is in the plane of its movement.
Now according to our invention we employ but one magnet bobbin which we
erect vertically on the base of the instrument; it has two pole pieces one above
and the other below. The armature we make of T form, the cross piece or head
(which is the armature properly so called) is vertical and its ends are in close
proximity to the pole pieces of the magnet. The armature is attached to and
carried by a spring blade fixed to the horizontal stem of the T piece. Thus in
this arrangement the pole pieces of the magnet are equally distant from the centre
of movement of the armature and they are able to attract it with equal efficiency.
The construction is also simpler than heretofore. The arrangement of the contact
spring on the back of the armature is as usual.
We can also employ two magnet bobbins placed horizontally one over the other
with pole pieces acting on the armature at two points equidistant from the centre of
movement.
Dated this 16th day of September 1889
:
CARPMAEL & Co.,
Agents..
COMPLETE SPECIFICATION.
Improvements in Electric Bells.
We, HARRISON GROVES, of 353 Strand, in the County of Middlesex, Merchant, and
JOSEPH HENRY STEWART, of 111 Ivanhoe Road, Denmark Park, in the County of
Surrey, Electrician, 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 improvements in electric bells.
Our improved electric bell is of the class commonly known as "trembling bells"
in which the armature of an electro magnet carries the hammer which strikes upon
the bell and also a spring contact piece.
the armature is attracted the bell is struck
circuit is opened. This opening of the
included permits the armature to fall back
017
These parts are so arranged that when
and in the same movement the electric
circuit in which the magnet coils a.e
under the influence of a spring blade

page_text: L
.
·
by which it is carried. The movement is then repeated and continues so long as the
outside circuit is complete.
In these bells it is usual to employ two magnet bobbins placed horizontally; one of
these attracts the armature at a point near to its centre of motion and the other at a
point at a considerable distance from it. In these bells the length of the armature is
in the plane of its movement.
Now according to our invention we employ but one magnet bobbin which we
erect vertically on the base of the instrument; it has two pole pieces one above and
the other below. The armature we make of T form, the cross piece or head (which
is the armature properly so called) is vertical and its ends are in close proximity to
the pole pieces of the magnet. The armature is attached to and carried by a spring
blade fixed to the horizontal stem of the T piece. Thus in this arrangement the
pole pieces of the magnet are equally distant from the centre of movement of the
armature and they are able to attract it with equal efficiency. The construction is
..also simpler than heretofore. The arrangement of the contact spring on the back of
:the armature is as usual.
We can also employ two magnet bobbins placed horizontally one over the other
with pole pieces acting on the armature at two points equidistant from the centre of
'movement.
In order that our said invention may be fully understood and readily carried into
effect we will proceed to describe the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a plan of an electric bell constructed in accordance with our invention.
Figure 2 is a side view and Figure 3 is an end view of the same.
a is a wooden base upon which is fixed a cast iron frame b. c is a magnet bobbin
and c care pole pieces. d is a T form armature, and e is a blade of spring steel
which serves to connect the armature with the lug on the frame b. A prolongation el
of the spring e serves to open and close the bell circuit, it has a small plug of
iplatinum inserted into it for this purpose and this when the armature leaves the pole
pieces falls into contact with a platinum point carried by a screw f. The screw fis
inserted into a post 9 mounted upon a vulcanite foot g' fixed into the frame b. When
the screw has been suitably adjusted it is held fast by a clamping screw as shown.
h is the bell, it is mounted on a post on the frame b. is the hammer fixed to the
armature. are clamping screws to receive the conducting wires of the battery
circuit. The circuit may be traced from the clamping screw k through the coils of
the magnet bobbin, to the frame b thence to the spring e and the screw f and so
to the clamping screw k¹. The core of the magnet c is carried upon a brass stud c³
fixed to the frame.
The details of construction may be varied but in all electric bells constructed in
accordance with our invention the two poles of the electro magnet act upon the
armature at equal distances from the centre of movement.
As before stated there may be two magnet bobbins one over the other; the position
of the pole pieces and armature remains unchanged. The armature may be mounted:
on an axis in-place of being carried by a spring blade. The arrangement of the bell
and hammer and contacts substantially is as usual.
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 :-
1. An electric bell substantially as described in which there is one magnet bobbin
and a pole piece at either end thereof and an armature in close proximity to the pole
pieces and moveable around a centre or axis from which the two ends of the armature
are equidistant.
2. An electric bell substantially as described in which there is an armature in close
proximity to the pole pieces of an electro-magnet and in which the said armature is
.:

page_text: moveable around a centre or an axis from which the two ends of the armature are
equidistant.
3. An electric bell substantially as described in which there is a magnet bobbin
erected vertically on the base of the instrument, having two pole pieces one above
and the other below and a T form armature carried by a spring blade so arranged
that the magnet poles act upon the armature at equal distances from the centre of
movement.
4. An electric bell substantially as shown by the annexed drawings.