An Automatic Switch for Electric Cooking Utensils.
Year: 1898

page_text: Date of Application, 13th Apr., 1898
Complete Specification Leff 13th Jan 1899 Accepted 25th Feb.
1899
Date of Application, 13th Apr., 1898
Complete Specification Loft 13th Jan 1899-Accented 25th Feb. 1899
PROVISIONAL SPECIFICATION.
An Automatic Switch for Electric Cooking Utensils.
We, FREDERICK JONATHAN DOWN, of Glengariff, Milton Road, Harpenden, &
JUSTUS ECK, of 5, Priory Road, Bedford Park, Chiswick, Electrical Engineers,
do hereby declare the nature of this invention to be as follows:-
In all electric cooking utensils at present in use for boiling or heating liquids
there is in the event of the liquid being evaporated or otherwise lost considerable
risk of the apparatus becoming overheated and thus causing damage to the
utensil or other things in the vicinity.
In order to obviate this we fix to the utensil an electric switch connected in the
heating circuit of the utensil controlled by a float so arranged that in the event
of the liquid in the utensil being dissipated the circuit is interrupted by the
working of the switch and overheating is prevented.
When the utensil is either entirely or partly full the float closes the circuit by
actuating the switch and the utensil can be again used.
We sometimes arrange the parts so that the circuit is interrupted when the
utensil is not quite empty and is not completed until the utensil is nearly full.
Day this
dov of April 1898
FRED. J. DOWN.
JUSTUS ECK.
An Automatic Switch for Electric Cooking Utensils.
We, FREDERICK JONATHAN DOWN, of Glengariff, Milton Road, Harpenden, and
JUSTUS ECK, of 5, Priory Road, Bedford Park, Chiswick, Electrical Engineers,
the same is
do hereby declare the nature of this invention and in what manner
to be performed, to be particularly described and ascertained in and by the fol-
lowing statement:-
In all electric cooking utensils as at present in use for boiling or heating
liquids there is in the event of the whole of the liquid being evaporated or other-
wise absent from the utensil considerable risk of the apparatus becoming over-
heated and thus causing damage to the utensil or other things in the vicinity.
In order to obviate this we fix in a suitable position and manner, in or
adjacent to, the utensil, a switch one form of which is shewn in detail in the
Figures 1 and 2 which are respectively the side sectional elevation and the plan
view
i

page_text: This switch is controlled by the float M which is connected through the lever K
and a link I with more or less backlash or freedom in its connecting parts to
the moving plunger H which works in a sleeve J.
The lever is supported by an arm O shewn attached to the cover N which
surrounds and protects the electrical parts of the switch.
The plunger acts as a guide to the pin Lattached to the upper end of which
is a spherical or cone shaped contact piece F.
Attached to F and to J is a chain which connects them loosely together and
prevents also the parts becoming separated in working.
The upper or fixed electrical parts consists of the two terminals A and B con-
nected in the electric circuit of the utensil, these are fixed in an insulating cap C
attached to the cover N and terminate in contact jaws and D.
The whole arrangement is shewn attached to a support G.
The clearance between the plunger H and the sleeve J is small but the length
of the sleeve is great compared with this the result being that we have both free-
dom from excessive friction and also freedom from leakage of steam into the
inside of the cover N. This enables us to maintain sufficient insulation between
the contact jaw to either interrupt the circuit or greatly increase its resistance
when the switch is opened as described.
When the utensil is filled with liquid above a predetermined level the float
forces the moving plunger upwards and wedges the contact piece I between the
contact jaws E and thus completing the electric circuit and enabling the
current for the heating coils to pass.
When the liquid falls below a certain predetermined height which is regulated
by both the length of the chain and the clearances or backlash in the connecting
link I the contact piece is withdrawn from the jaws D and E and the circuit
interrupted.
:
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is;
-
!
1. A method of protecting electric cooking utensils from becoming overheated
should the liquid they are intended to contain be either absent or less than a
predetermined quantity.
2. A means of protecting electric cooking utensils from becoming overheated
should the liquid they are intended to contain be either absent or less than a
predetermined quantity.
FREDERICK JONATHAN DOWN.
JUSTUS ECK.