US 2490602 A
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Description (OCR text may contain errors)
Dec. 6, 1949 w. o. SCHICK ELECTRICAL HEATING ELEMENT SUPPORT Filed Aug. 18, 1947 INVENTOR. WENZEL 0. SCHICK.
fMq W A TORNEY.
Patented Dec. 6, 1 949 UNITED STATES PATENT OFFICE ELECTRICAL HEATING ELEMENT SUPPORT Wenzel 0. Schick, Detroit, Mich.
Application August 18, 1947, Serial No. 769,173
2 Claims. (Cl. 219-37) This invention relates to an electrical heating plate and, in particui-ar, it relates to the combination with an electrical heating element of a base member for supporting the heating element.
Usually, heating elements are associated with a supporting member either by being wrapped around the supporting member when ribbon heating elements are used, or the heating elements assume the formation of a wire spring positioned in a single plane in relation to the supporting base. I have found that greater efiiciency can be obtained by using a ribbon heating element and by positioning the ribbon so that its principal flat surface is supported by a base member in a substantially uniform plane. Ordinarily, it is dinicult to provide a base member which will maintain the ribbon heating elements in such a supported position. I have found that such a base member may be formed in a single piece of refractory material.
In general, the base member of my invention consists of a substantially circular or disc-like formation of refractory material having a circular groove formed therein at a location bordering the principal outer edge of the base member. The principal surface of the base member constitutes a plurality of ridges and valleys. The valleys provide a retaining portion for the reception of a length of heating element ribbon. The ridge portions at alternate ends include an extension which projects beyond the edge of the circular groove forming an over-hanging portion which serves as a locking means for retaining the ribbon in place.
It is, therefore, among the objects of my invention to provide a heating element and a base therefor in which the base is formed of a single piece of refractory material; to provide a base for an electrical heating unit capable of supporting a ribbon heating element in a substantially flat and uniform plane; to provide a heating unit in which substantially the entire heating element presents a fiat face directed against the surface or article to be heated; and, to provide a heating unit of the character described which may be manufactured economically and emciently.
These and other objects and advantages will appear more fully in the following detailed description when considered in connection with the accompanying drawing, in which:
Figure 1 is a plan view of a heating unit forming an embodiment of my invention;
Figure 2 is a transverse view thereof, in section, taken along lines II-II of Figure 1; and
Figure 3 is an enlarged view, in section, of a.
2 portion of the heating unit taken along lines III-III of Figure 1.
With reference to the drawing and in particular to Figure 1, I show an embodiment of my invention in the form of a substantially disc-like memher i. This member is made of a refractory material capable of resisting relatively high temperatures. In accordance with the manufacture of articles of this type the base member I is formed in a molding operation. Near the outer periphery of the member I is a groove 2 which extends in a complete circle.
The principal surface of the heating unit is made up of a plurality of ridges 3 and Valleys 4. The highest point of the ridges 3 extends slightly below the top surface of the member This dimension is approximately 2 inch. Also, the pitch or distance from ridge to ridge is approxi mately A; inch. Alternate ends of the ridges 3 form extension members 5 which overhang the groove 2.
A heating element 6, in the form of a ribbon of approximately Te inch in width and .010 inch in thickness, is associated with the member i so as to lie in the base of the valleys 4.
The overhanging portion 5 of the ridges provides a support around which the ribbon may be wrapped and locked in place. The locking is accomplished because of the fact that the ribbon extends partly underneath the overhanging portion 5. By this arrangement, the heating element 6 may be securely affixed to the base member I without danger of it becoming loose or disengaging from the base member. When the heating element 6 is tightened in the manner described, the fiat surface of the ribbon lies fiat in the valleys 4 with the principal surface of the member I.
Suitable terminals such as 1 and 8 extend through the base member i for securing the ends of the heat ng element and for forming means of attachment for wires for supplying the desired current.
Since base members of this general construction are ordinarily formed in a molding operation, it is necessary to provide apertures 9 which extend through the base member beneath each of the overhanging portions 5. The purpose of these apertures is to permit the entry of pins (not shown) to extend through the aperture 9 to form a filler beneath the overhanging portions 5 to facilitate removal of the base member I from the mold within which it is cast.
As an additional precaution against the possibility of the ribbon 6 from moving too far out of the grooves 4 and thus endangering contact with the article or surface which may rest on the heating unit, I provide guards iii which are positioned transversely of the ridges 3 and which are recessed therein. These guards are formed of narrow strips of mica and are three in number. The top of the mica strips lie below the top of the ridges 3.
In order to provide adequate clearance for the wrapping of the ribbon around the projections 5 the groove 2 is formed to a greater depth than the bottom of the valleys 4.
As thus shown and described, it is believed apparent that I have provided a novel heating unit which is capable of efficient performance and which, because of its integral base construction; may be manufactured eificiently and economi-. cally. 7
While I have shown and described a preferred embodiment of my invention, it is to be undera stood that it is susceptible of those modifications which appear obviously within the spirit of the invention and as appearing within the scope of the appended claims.
Having thus described my invention, what I claim and desire to protect by Letters Patent is:
1. In combination, a support and an electrical-i heating element comprising, a base member of a fiat construction formed of an electrical insulating and heat resisting refractory material, said 1 base member having a groove formed therein at a location near the outer periphery of the base member and bordering at least the principal outer edge of the base member, a plurality of parallel ridges formed in the surface of the base member within the area defined by said groove, the parallel ridges defining valleys adapted for the recep tionv of said heating element throughout its,
length, the bottom of said groove being of a greater depth than the bottom of the valleys, and extension members forming a continuation of at;
least some of the ridges constituting portions overhanging the said groove, whereby the extension members function as hooks around which the heating element may be looped for retaining the element securely in the valleys of the base member, said heating element comprising a flat metallic ribbon positioned at the base of said valleys with the face of the ribbon parallel to the principal face of the support.
2. In combination, a support and an electrical heating element comprising, a base member of a fiat construction formed of an electrical insulating and heat resisting refractory material, said base member having a groove formed therein at a location near the outer periphery of the base member and bordering at least the principal outer edge of the base member, a plurality of parallel ridges formed in the surface of the base member within the area defined by said groove, the parallel ridges defining valleys adapted for the reception of said heating element throughout its length, the bottom of said groove being of a greater. depth than the bottom of the valleys, and an extension member forming a continuation at one end of each ridge and constituting aportion overhanging said groove, the extension,
members being associated with alternate ends ofi REFERENCES CITED The following references are of record in; the
file of this patent:
) UNITED STATES PATENTS Number Name Date 1,561,893 Williams Nov. 17, 1925 1,574,308 Rutenber Feb. 23, 1926 1,645,867 Louthan Oct. 18, 1927 1,680,749 Shroyer Aug. 14, 1928 1,910,701, Lebau May 23, 1933 2,464,147 Myers Mar. 8, 1949