An Improved Arrangement of Electric Call or Sound Signalling Apparatus.
Year: 1895

page_text: Date of Application, 27th May, 1895
Complete Specification Left, 18th Feb., 186-Accepted, 28th Mar., 1896
PROVISIONAL SPECIFICATION.
An Improved Arrangement of Electric Call or Sound Signalling
Apparatus.
I, WILLIAM ARTHUR PRICE of The India Rubber Company's Works
Silvertown in the County of Essex, Electran do herchy declare the nature of
this invention to be as follows:-
This invention relates to a novel and simple construction of apparatus for
effecting, by the aid of an electric current, calls or sounding signals.
To this end, I provide a metal box or case, preferably cylindrical, and this
I cover with a thin iron diaphragm, securing the same in place by a ring of
ebonite or other insulating material pressed down on the diaphragm, so as to clamp
it by a ring, which is screwed to the box or case.
Fixed to and projecting through the ring of ebonite, is an adjustable screw,
which makes contact with the diaphragm.
Within the box, and at the centre of the bottom thereof, is fitted, so as to be
adjustable from the outside, au iron pole piece, which is surrounded by a coil of
wire, and forms therewith an electromagnet. This magnet, when energized, serves
to attract the metal diaphragm, and thereby to produce audible signals. One end
of the coil of wire is led out through a hole in the box, and the other is connected
to the box, & so to the metal diaphragm, which is clamped thereto, as ab ve
mentioned. A wire is brought down from the contact screw through a hole in the
metal diaphragin and through the bottom of the box. When a battery is connected
to this pendent wire, and to the coil, the pole piece is magnetised and the diaphragm
attracted. This breaks the contact between the diaphragm and its contact screw,
and interrupts the circuit.
The diaphragm, through the elasticity of the metal, then returns to its first
position, and the series of movements is repeated.
The result of this intermittent current is to throw the diaphragm into a state of
vibration, and thus to cause it to emit sounds. Openings in the side of the box
allow the sounds to be heard more freely.
Dated this 25th day of May 1895.
NEWTON & SON,
Agents for the Applicant.
COMPLETE SPECIFICATION.
An Improved Arrangement of Electric Call or Sound Signalling
Apparatus.
I WILLIAM ARTHUR PRICE of The India Rubber Company's Works,
Silvertown, in the County of Essex, 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 relates to a novel and simple construction of apparatus for
effecting, by the aid of an electric current, calls or sounding signals, setting up, for
this purpose, vibrations in a thin iron diaphragm, after the manner of the telephone.

page_text: In the accompanying drawings, I bave shown two arrangements of my invention
in which an adjustable electro-magnet fitted in a metal box is used to set the
diaphragm vibrating as the electric circuit is made and broken.
Fig. 1 shows in sectional elevation an arrangement of sound-signalling apparatus
in which a metal box or case A, preferably cylindrical, is used, to contain the
sounding apparatus. To this box is fitted a thin ron diaphragm B, which is
secured in place by a ring of ebonite or other insulating material C, pressed down
by a clamping ring D, screwed to the box or case A.
Fitted to the ring of ebonite is a flanged metal boss E, shown best in the inverted
plan view, Fig. 2. This flanged boss is beld in place by a screw passed through its
Hange, and screwed into the ebonite. The boss E is tapped to receive a platinum
pointed adjustable screw F, which makes contact with the diaphragm through a
platinum contact piece carried by the diaphragm.
Within the box, and at the centre of the bottom thereof, is fitted, so as to be
adjustable from the outside, an iron pole piece G, which is screwed into the bottom
of the box, and is surrounded by a coil of wire H, and forms therewith an electro-
magnet. This magnet is energized from a battery I, one end of its coil being led
out through a hole in the box, and connected to the battery by a wire 1, as shown,
while the other end of the coil is in metallic contact with the box which carries the
metal diaphragm as above mentioned. To complete the circuit, a wire 2 is brought
down from the flanged boss E (which carries the contact screw F), through a hole
in the metal diaphragm B, best seen in the detached plan view Fig. 3, where b is
the hole, and the platinum contact piece. The wire 2 thence passes through the
bottom of the box, and so on to the battery. When the electric circuit is established,
the pole piece G is magnetised, and the diaphragm attracted. This breaks the
contact between the diaphragm and the contact screw F, and interrupts the
circuit.
The diaphragm, through the elasticity of the metal, instantly returns to its first
position, and the series of movements is repeated.
The result of this intermittent current is to throw the diaphragm into a state of
violent vibration, and thereby cause it to emit sonoious sounds. A central opening
in the ring C, and openings in the side of the box, allow the sounds to be
disseminated freely.
In Figs. 4, 5, and 6, I have shown a modification of the sound-signalling
apparatus of Fig. 1, the construction being somewhat simplified, without affecting
the efficiency of the instrument.
Fig. 4 is a sectional elevation of the electric call;
Fig. 5 a top view of the box or case; and
Fig. 6 a top view of the diaphragm detached.
The same letters of reference iudicate corresponding parts in the two
arrangement-.
The platinum pointed contact screw is, in this arrangement, fitted to the metallic
cover C of the box A, which is open at its centre, like the ebonite ring of Fig. 2.
This screw is adjustable as before mentioned, so as to touch the platinum contact
piece of the diaphragm B.
Instead of this diaphragm resting in metallic contact on the case A, it is
insulated by being coated at its edge with an overlapping ring of vulcanite, as
shown at Fig. 6, which represents the diaphragm as fitted with a platinum contict
piece, as in Fig. 3, but provided with no opening for the passage through it of a
wire from the contact screw
In the present example, the wire 2, leading through the bottom of the box to
the battery, is soldered to the back of the diapbagm, but the connection of the coil
wire with the battery and the case is the same as in Fig. 1, as is also the adjustable
core or pole piece G of the electro-magnet, such pole piece projecting through the
bottom of the box, and being formed to receive a key or its equivalent, for turning
it to adjust its height with respect to the diaphragm B.
८
The cover C of the box, which holds the diaphragm in position, is secured by

page_text: screws to the flange of the box, instead of being screwed onto the box, like the
clamping ring D of Fig. 1.
This change in the mode of attachment of the clamping parts is rendered
necessary by the contact screw being carried by the cover C.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
:-
The construction of electric call or sound-signalling apparatus as above described,
in which a thin iron diaphragm is, is by means of an electro magnet, rapidly
vibrated, and caused to give forth audible signals.
Dated this for day of reoruary 10
NEWTON & SON,
Agents for the Applicant.
NEWTON & SON,
Agents for the Applicant.