US2330867A - Electric heating plate - Google Patents

Description

Oct. 5, 1943. E. CHALLET 2,330,867

ELECTRIC HEATING PLATE Filed Sept. 9, 1940 Patented Oct. 5, 1943 ELECTRIC HEATING PLATE Etienne Challet, Bern, Switzerland, assignor of one-fourth to the firm Entreprises Electriques Fribourgeoises, Fribourg, Switzerland, a firm of Switzerland Application September 9, 1940, Serial No. 356,063 In Switzerland July 8, 1940 1 Claim.

This invention due to Mr. Etienne Challet, Bern, Switzerland, relates to an electric heating .plate of the type having at least two heating resistances and a heating body composed of at least two distinct body portions.

The object of the invention is to devise a heating plate of this type which differs from those manufactured hitherto in that each one of the heating resistances provided is applied to both the distinct portions of the heating body.

The invention also consists in the further features as hereinafter described and set forth in the dependent claim.

The accompanying drawing illustrates, by way of example, one embodiment of the invention.

Fig. 1 is a top plan view of the heating plate, showing the two distinct body portions thereof;

Fig. 2 is an elevation of the plate, showing the whole construction thereof, and

Fig. 3 shows the connection scheme of the plate.

The electric heating plate as represented in Figs. 1 and 2 comprises a frame I carrying a heating body 2. The latter is constructed of an inner circular plate In slidably mounted on the frame so as to be adjustable in vertical direction, and of an outer annular ring 2!) concentric with said inner plate and formed integral with or suitably secured to said frame. To the lower end of the frame are fixed the terminals 4; moreover, said end of the frame forms a suitable cage adapted to house a compression spring 3 which bears against the inner plate 2e and tends to raise the same relative to the outer ring 2n so as to adapt the contacting surface of the heating body to the area. of contact of the pan or pot placed on said body. All of these features of construction are known in the art and therefore need not be further described herein,

The heating body 2 accommodates two resistances 5 and 6. The resistance 5 is formed to include two branches 5a. and 5e connected in series and disposed, one within the mass of the outer ring 2b, and the other within the mass of the inner plate 2e. Also the resistance 6 comprises two branches 6a and 6b placed within the masses of the outer ring 2n and the inner plate 2e,'re-

spectively. The current intensity of the heating body 2 may be varied by connecting the two resistances 5 and 6 in parallel, or by utilising only one of said resistances or by connecting them in series; the heating effect of the body 2 is thus stepped to three different degrees. It is to be seen, however, that in each of the three cases the whole of the heating body 2 is heated since both the distinct body portions 1. e. the inner plate 25 and the outer ring 2b are always heated by one of the resistances applied to them, whereas in known heating plates heretofore constructed it is generally found that each of the resistances provided is applied but to a single portion of the heating body. Consequently, when disconnecting one of said resistances the corresponding portion of the heating body is not heated but makes use of the heat transmitted to the pan by another heated body portion, the result of this known arrangement being an unequal distribution of heat as also a loss of heating power.

It should be understood that it is not intended to limit the invention to the exact details of construction shown and described, for various modifications within the scope of the claim may occur to persons skilled in the art. In particular, the invention may be applied also to heating plates having a heating body with fixed outer and inner 'body portions or a heating body comprising more than two distinct body portions.

What is claimed and desired to be secured by Letters Patent is:

In an electric heating plate of the kind having at least two concentric units mounted for relative vertical resilient displacement in a rigid frame, the combination with said movable units of a resistance assembly comprising at least two concentrical resistance elements in each heating unit, electrical coupling connections connecting each resistance element of one unit with a resistance element of another unit, said connections being adapted for relative movement of said units, and series or parallel connections of said resistance assembly, whereby four degrees of heat may be equally distributed on the whole heating plate.

ETIENNE CHALLET.

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