Improvements in Electrical Heating Devices.
Year: 1894

page_text: Date of Application, 31st July, 1894-Accepted, 22nd Sept., 1894
COMPLETE SPECIFICATION.
Improvements in Electrical Heating Devices.
A communication by JOSEPH ARTHUR G. TRUDEAU, of Ottawa, in the Province
of Ontario, in the Dominion of Canada.
1, GEORGE CECIL DYMOND M.J. Mech. E., of The Agency for Foreign Patent
Solicitors, 6 Lord Street, Liverpool, and 6, Bank Street, Manchester, both in the
County of Lancaster and 323 High Holborn in the County of Middlesex, Patent
Agent, 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 electrical heating devices, and consists essentially in a
novel construction of the same whereby the object to be heated is itself made to
constitute the core of a coil through which alternating currents of electricity are
passed.
By this construction, the Foucault or eddy currents are caused to generate
heat in the enclosed or encircled object, and all the heat produced is generated
within the object itself instead of in a separate receiving shell or budy.
The invention further consists in other features and details of construction,
hereinafter set forth, chief among which is an arrangement of terminals whereby
insertion and removal of the object are caused to complete and to interrupt the
circuit.
In the drawings-
Figure 1 is a perspective view of the improved heating device designed for
beating curling tongs;
Figure 2, a sectional view of the same ;
Figure 3, a diagrammatic view;
Figure 4, a sectional view of the device in a form suitable for heating soldering
irons;
Figure 5, a diagrammatic view of the same; and
Figure 6, a diagrammatic perspective view of a heater suitable for laundry
irons;
Referring first to Figures 1, 2 and 3, the construction of the device will be
explained.
A, indicates a spool or bobbin which may be conveniently made of wood, and
B a coil of insulated wire of suitable length wound upon said spool. A suitable
base C is provided upon which the spool is secured and through which the terminals
of the wire are preferably carried to the under side, for the purpose of preventing
accidental bridging of the wires by loose objects.
An ordinary switch or circuit breaker may be introduced into the conductor at
any suitable point; but in practice it is preferred to interrupt the coil at some
point, and to so arrange its terminals that the object to be heated shall form a
connection between them, when properly inserted into the coil.
This construction is illustrated in the several figures. Thus in Figures 1, 2 and 3,
the cuil B is interruptel at one end of the bobbin, and the ends are attached
respectively to spring clips or plates a and b which are represented as projecting
from the end of the spool or bobbin. The clips a and b are fashioned to conform to

page_text: the end of the implement D, and are so set or adjusted that when said implement
(here represented as curling tongs) is inserted, its forward end shall enter between
the clips and press them slightly apart. This ensures good contact, and the inserted
portion of the tongs being of good conducting metal, the circuit of the coil is
completed in and by the act of inserting them and is interrupted through their
withdrawal.
As shown in Figure 2, the tongs enter directly within the bore of the spool or
bobbin A, and this will be found reasonably safe in practice, because only a
moderate heat is required for curling tongs, and the coil will ordinarily be wound
to produce only a safe heat; but a lining of asbestos, mica, or other incombustible
material may be provided if deemed advisable.
In Figures 4 and 5 such a lining c is shown in a heater designed for soldering
irons. This heater is in all essential particulars the same as the preceding, but as
the point requires to be heated to a quite high temperature, it is preferred to place
the spring clips ab within the coil as shown in Figures 4 and 5.
E indicates a rest or support for the shank or stem of the iron, secured to the
base board C, and serving to hold the iron in axial alignment with the coil.
Figure 6 shows diagrammatically the same plan of construction adapted to a
laundry iron heater. Such irons being commonly made with detachable handles, the
coil may conform pretty closely to the contour of the iron, though sufficiently open
at one end to admit the full width of the iron.
In this figure the coil terminals a bare represented as rigid studs, upon which the
iron rests.
It is obvious that the coil will be fashioned to suit the particular implement for
which it is intended.
It is of course possible to employ uncovered wire, provided its coils be separated
from each other and from all other conducting bodies, but such air-insulation while
comprehended within this invention, is not deemed desirable.
Rests d and e are placed upon the ends of spool or bobbin A, to receive the tongs
when not in use or not being heated. Such provision lessens the tendency to place
and leave the implement within the coil when not requiring to be heated, and thus
tends to prevent waste of current.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondent, I declare that what I claim is-
1. An electric heating device consisting of an insulated wire coil adapted to
receive a current of electricity, and a metallic implement to be heated, said imple-
ment being combined with the coil and so placed with reference thereto that it shall
constitute a core for the coil and be heated by the eddy currents formed in it by
the electric current in the coil.
2. In combination with an insulated coil adapted to receive a current of electricity,
a metallic implement inserted into but removable from said coil; whereby the
implement is adapted to be directly heated by eddy currents and to be removed to
any required place of use.
3. In an electric beating device, the combination of an interrupted coil, metallic
terminals for the separated ends of the coil, and an implement to be heated, said
implement being removably placed within the coil and serving both as a core
therefor, and as a connection between the coil terminals.
4. The herein described heater, consisting of an insulated wire coil B, and a
removable metallic core D constituting part of an implement to be heated.
5. In combination with interrupted coil A, terminals a and removable core D
constituting part of an implement to be heated.
6. The herein described electric tongs-heater, comprising the following elements
in combination; a spool or bobbin A provided with rests de; an insulated coil B
provided with terminals a b; a base C, and a removable core D, substantially as
shown.

page_text: 7. In combination with coil B and removable core D, a pyro-insulating body c
interposed between them to protect the coil.
11
ليمي
CLI
1001
WM. P. THOMPSON & Co.,
Agents.