US2413536A - Electric heater - Google Patents

Description

Dec. 31, 1946. WIE ND 2,413,536

ELECTRIC HEATER Original Filed Aug. 23, 1941 2 Sheets-Sheet 1 [aw/N L. VV/EGHND INVVENTOR BY MWi/m AT TORNEYS Dec. 31,1946. E. L. WIEGAND 2,413,536

' ELECTRIC HEATER Original Filed Aug. 23, 1941 2 Sheets-Sheet 2 [aw/N A. mesa/v0 INVELJJ' R M WW ATTORNEf Patented Dec. 31, 1946 ELECT-RIC HEATER Edwin L. Wiegand, Pittsburgh, Pa., assignor to Edwin L. Wiegand Company, Pittsburgh, Pa'., a corporation of Pennsylvania Original application August 23, 1941, Serial No.

408,073. Divided and this application December 9, 1942, Serial No. 468,382

6 Claims.

My invention relates to electric heaters, more particularly to electric range units, and the principal object of my invention is to provide new and improved electric heaters of these types.

This application is a division of my copending application Serial Number 408,073, filed August 23, 1941.

In the drawings accompanying this specification, and forming a part of this application, I have shown, for purposes of illustration, one form which my invention may assume, and in these drawings:

igure 1 is a plan view of an electric range unit illustrating an embodiment of the invention,

Figure 2 is a bottom plan view of the embodiment, drawn to a smaller scale,

Figure 3 is a side elevation of the embodiment,

Figure 4 is a bottom plan view, the reflector being omitted to better illustrate certain of the parts,

Figure 5 is a sectional view corresponding generally to the line 5-5 of Figure 4,

Figur 6 is a fragmentary sectional view corresponding generally to the line 6-0 of Figure 5, and

Figure '7 is an enlarged sectional View corresponding generally to the line of Figure 5.

The electric heater or range unit embodying my invention may comprise one or more heating elements, in this instance two elements In and H. As herein shown, each element comprises a tubular metal sheath within which is disposed electrical resistance heating means 12. embedded in refractory electrical-insulating heat-conducting material i3. The insulating material 13 may be in the form of suitable granular, comminuted, or powdered refractory material, preferably compacted to a dense hard condition.

Each of the elements I!) and H has an active portion which is preferably triangular in crosssection, as best shown in Figure 5, and the active portion of each element is of generally spiral form. Referring particularly to Figures 1 and 4, it will be noted that the element l I has a central portion wound about itself for one turn, and the remainder of the active portion of the element H is then intercalated with the element I0. Therefore, the element II has portions disposed side-by-side and then has portions disposed side-by-side with portions of the element l0.

This particular construction makes possible a distribution of heat not attainable with structures of the prior art.

For example, assuming that the elements l8 and II are electrically connected to an electrical source of, say 220 volts, in such manner that either one or both may be energized, the elements herein shown are designed to provide 2000 watts when both are simultaneously energized. The element H is so designed that when it only is energized, it will provide 1400 watts, and this wattage will be spread out over a considerable area, but with some concentration at the center. The element 10 is so designed that when it only is energized, it will provide 600 watts. 0f course, the wattages will be in relation tc the voltage used, and in the embodiment it is possible to have other heats. For instance, if volts were used,

the elements H) and H herein disclosed are sodesigned that when both are energized they will provide 500 watts; when the element H only is energized, it will provide 350 watts; and when the element It! only is energized, it will provide watts. Also, it will be apparent that it is possible to employ a switch connected to different voltages, as for example 220 volts and 110 volts, and so designed that the elements may be singly or together energized with either voltage.

The element I0 has end portion m, 722. and the element II has end portions 113. 104. Each of the end portions terminates in a connection terminal, respectively numbered Hi. 15. i5. and H, which may be housed in a suitable insulating block or housing !8. The terminals !5 and iii are here shown bridged by a bridge plate l9, and the connection terminals may be connected to a source of electricity (not shown) through the means of a proper electrical switch (also not shown).

The end portions 121, m. m, m are all of substantially circular or rounded section, to facilitate bending. and preferably only the spiral portions of the elements are of triangu ar section. The elements such as may be embodied in the range unit herein shown may initially comprise a tubular sheath of substantially circular crosssection into which t e resistor and insu ating material have been introduced endwise. and may have their active portions side-pressed in suitable dies to a desired triangular cross-section, and the element may be press-forged as set forth in my conending application Serial Number 361997, filed October 21, 1940. Accordingly, the active portion of each heating element H0 or H comprises a tubular sheath having two walls 20, 2 I, the major portions of which are flat and make between them an angle of approximately 60, these walls merging in a rounded apex 22. The upper wall 23 is substantially entirely flat and makes with the walls 20, 2| angles of 60 respectively.

3 In the embodiment shown, the flat portions of the walls 2! 2! are respectively of less cross-sectional extent than the substantially entirely flat upper wall 23.

As best seen in Figure 5, the upper walls 23 lie in a common plane. Therefore, if an object, such as a cooking vessel, is placed upon the heating means comprising the heating elements M, l l,

the vessel will be in contact with the flat upper walls 23, and therefore is in excellent heat-conducting relation with respect to a relatively large area of the heating means, so as to-be heated mainly by conduction. The generally downwardly facing lower walls 26, 2| of each heating element radiate some heat diagonally downwardly in respectively opposite directions, considering any given portion of an element, and this heat is reflected upwardly by a reflector 24 which gen erally underlies the heating elements I9, ll.

The end portions 101, a, p 104 extend downwardly from their respective active portions, and then have their respective extremities bent slightly upwardly toward the insulating block [8, thus forming a drip point 25, best shown in Figure 5 with reference to the portion 193. Preferably all the end portions are brought together at an edge of the range unit, as herein shown, so that external electrical connection thereto is facilitated.

Tracing the various portions of the elements, and starting with the portion 173 of the element II, it will be seen that the portion 203 extends toward the center of the range unit, upwardly to the active portion, and the active portion is wound about itself at the center at least once, as shown at 115, and then has an intermediate portion 736 spiralling to the end portion 124. The element ill starts with the end portion 101 extending upwardly to its active portion, and this active portion is intercalated with respect to the active portion of the element ll, except at the central portion 105, and terminates in the end portion 122.

The apexes 22 of the heating elements Id and II define the under side of the active portion of the heating means, and this under side is mounted upon'a supporting means 26, which may be a grating or grid comprising a plurality of generally radially disposed arms 21 the embodiment shown, the supporting means 26 comprises a straight sheet-metal member, providing the arms 21, 28. The arms 29, 30 are formed by a sheet-metal member bent so as to form a'central generally U-shaped bight 33, and the arms 29, 30 extend from this bight in generally V-shaped relation with respect to each other. Likewise, the arms 3!, 32 are formed by a sheet-metal member bent so as to form a central generally U-shaped bight 34, and the arms 3!, 32 extend from this bight in generally V-shaped relation with respect to each other. The bights 33, 3d are fastened to opposite sides of the sheet-metal member forming the arms 21, 28, as by means of rivets 35. If desired, all, orcertain of the arms may be provided with stiffening ribs, as indicated by the numeral 36.

. Means may be provided to hold the heating means comprising the elements assembly-with the supporting means 26. In the embodiment shown, this means comprises a plurality of slots 3? formed in the arm 27, each slot generally underlying the section of the respective heating elements traversed by the arm 27, as best seen in Figure 5. A plurality of clips 38 are secured to the apex of each element in, H- adjacent the arm 21, as by spot welding, each to 32 inclusive. In

H], H in desired clip having a tongue 39 extending downwardly generally along a surface of the arm 21, extending through a respective slot 31 and having its, extremity bent upwardly, as best seen in Figure 7. Thus, the elements H], II are held against substantial movement toward or away from the supporting means 25. Desirably, the slots are elongated in a radial direction, and in this direction are longer than the width of the clips 38 to allow for relative movement of the elements in a plane defined by the upper margins of the arms 21 through 32, so as to accommodate for expansion and contraction of the heating elements. In this manner, binding, straining, or warping of the parts is prevented.

The extremity of the arm 28 is formed with a projection til fitting into an aperture 4| in a bracket 52. The bracket 42 is longitudinally curved, as best seen in Figure 4, and at its lower extremities is provided with fingers 43 extending inwardly of the range unit, and terminating in upwardly directed ledges 44. An upper side margin of the bracket 42 has an angular extension 45 upon which the apex of the element It, adjacent the end portion 122, rests, thus supporting this part of the element ll), since it is spaced a substantial distance from the arm 32. The lower margin of the bracket 42 is formed with a curved recess 46 (see Figure 6) to pass the adjacent parts of the end portions 101, 102, an, 114, and the adjacent parts of the end por-. tions p1, 1174 bear against the defining margin of therecess 46 for the purpose of steadying and aiding in the support of the heating elements H), i l. A ground screw 41 is threaded into a tapped aperture formed in the bracket 42, and is adapted to receive a conductorwhich may be grounded to a suitable ground, such as a stove frame or the like.

Circumscribing the outer ends of the arms of the supporting means 26 is a ring 58, havin a cylindrical portion 59 merging with an annular portion 50 in turn merging with a downwardly extending cylindrical flange 5|, adapted to engage a range top (not shown). The arms 21,35, and 32 are longer than the other arms, and the longer arms are provided with projections '52 forming shoulders withthe respective arm, the projections being adapted to engage respectively in apertures 53 formed in the cylindrical portion 49,- and the shoulders being adapted to bear against the adjacent inner peripheral surface of the cylindrical portion, so that the ring'48 is adapted to support the supporting means 26. The arm 2?, adjacent its extremity, is provided with a downwardly extending hook 54. As here shown, the hookis a separate piece and is spot welded to the arm 21. The hook 54 has aninclined surface 55 terminating in a hook-tip 56.

The reflector 24 is disposed below the supporting means 26, and as best shown in Figure 5, is of generally conical form, or to describe it differently, is generally dish-shaped, with the opening of the dish directed means 25. The peripheral margin of the refiector 24 is formed with a downwardly oiiset curved portion 51, and the reflector, in line with the hook 5 1, is formed with a slot 58 of'a length to pass the hook 54. The reflector 24 has a pocket 59 of generally U-shaped cross-section, as best seen in Figure 6, the bottom wall of the pocketextending radially inwardly, and merging with the reflector wall adjacent a central opening 60 formed in the reflector 24. On either side of the pocket 59, the reflector wall isformed with uptoward the supporting wardly pressed areas 6|, positioned so that the recess surfaces thus formed are adapted to receive respective ledges M. The hook 54 and the ledges M provide hanger means from which the reflector is adapted to be hung.

The reflector 2a is adapted for assembly and disassembly with respect to the supporting means by movement generally edgewise of the supporting means. For example, to assemble the reflector 2:3 with the supporting means 25, the reflector 2a is moved in a direction generally parallel to the bottom edges of the arms 2'! to 32 so that the pocket 59 moves to cover the adjacent parts of the end portions 111, 392, p3, and 2a.. and the reflector is moved a distance sufflcient to align the slot 58 with the hook 5d, at which time the reflector is lifted slightly to pass the hook through the slot, and the reflector 24 is again moved slightly in the first direction until the recess surfaces formed by the upwardly pressed areas 5! align with respective ledges it. At this time, the reflector is permitted to hang, with the recess surfaces of t e upwardly pressed areas resting on the ledges 44, and the reflector surface adjacent the slot 58 resting on the hook surface 55. The hook-tip t3 bears against the offset margin 51 of the reflector, and the hook surface 55 is inclined, so that either or both prevent unintentional reverse disassembly movement of the reflector. To disassemble the reflector 24 from the supporting means 26, a reversal of the assembly movement is necessary.

As best seen in Figure 5, the peripheral margin of the reflector 2% is spaced from the cylindrical wall 49 of the rim 48, to provide a substantially annular air opening 62 (except at the pocket 55!) so that air may enter this space radially inwardly and proceed upwardly through the grating and heating element assembly. The downwardly inclined wall of the reflector 24 provides a drainage surface for any substances spilled on the reflector, and these substances may drain through the central opening M, which opening also provides an additional air opening.

A central medallion 63, or the like, may be provided to cover a desired amount of the space at the center of the heating means. As here shown, the medallion t3 rests on the upper edges of the arms 21 through adjacent the bight portions 35 i, and has marginal extensions, forming four legs 64, which are secured to the side surfaces of the bight portions 33, 34 in any suitable means, as for instance by spot welding.

From the foregoing it will be apparent to those skilled in the art that I have accomplished at least, the principal object of my invention, and it also will be apparent to those skilled in the art that the embodiment herein described may be variously changed and modified, Without departing from the spirit of the invention, and that the invention is capable of uses and has advantages not herein specifically described; hence it will be appreciated that the herein disclosed embodiment is illustrative only, and that my invention is not limited thereto.

I claim:

1. An electric heater, comprising: electrical heating means; supporting means, supporting said heating means, having a pair of spacedapart ledge means, and a hook portion, spaced from said ledge means; reflector means, generally underlying said heating means and said supporting means, having a curved marginal surface, said reflector means also having an aperture adjacent said curved marginal surface for passing said hook portion and a pair of upwardly pressed areas spaced to correspond to the spacing of said ledge means, the construction being such that the recess surface formed by the upwardly pressed areas receives and rests on said ledge means and said hook portion extends through said reflector means aperture and engages the adjacent under surface of said curved marginal surface and holds said reflector means in assembled position with said supporting means.

2. An electric heater, comprising: electrical heating means; supporting means, supporting said heating means; connection means, constructed and arranged to connect said heating means and said supporting means, and to hold them against substantial lateral movement; reflector means, generally underlying said heating means; and holding means, normally holding said reflector means assembled with said supporting means, comprising substantially stationary portions normally underlying portions of said reflector means supporting said reflector means on said holding means, and said holding means and said reflector means being constructed and arranged to permit relative lateral movement of said reflector means to bring respective portions out of opposition and thus permit said reflector means to be moved substantially perpendicularly away and thereby disassembled from said supporting means.

3. An electric heater, comprising: electrical heating means; supporting means, supporting said heating means; connection means, constructed and arranged to connect said heating means and said supporting means, and to hold them against substantial lateral movement; reflector means, generally underlying said heating means; and holding means, normally holding said reflector means assembled with said supporting means, comprising substantially stationary portions normally underlying portions of said reflector means supporting said reflector means on said holding means, and said holding mean and said reflector means being constructed and arranged to permit relative lateral movement of said reflector means to bring respective portions out of opposition and thus permit said reflector means to be moved substantially perpendicularly away and thereby disassembled from said supporting means; said reflector means and said supporting means including portion-s interengaging when said reflector means is in assembled position and constructed and arranged thereupon to resist said relative lateral movement of said reflector means.

4. An electric heater, comprising: supporting means; electric heating means mounted upon said supporting means; a reflector; means for carrying said reflector in position below said supporting means, including a plurality of ledge means carried by and below said supporting means and interengageable with underside portions of said reflector, at least one of said ledge means being provided by the jaw portion of hook means having a neck portion extending through an aperture in said reflector, and said plurality of ledge means and said reflector being relatively so constructed and arranged that said reflector may be assembled with and disassembled from said ledge means solely by relative bodily movement of said reflector with respect to said ledge means and generally edgewise with respect to said grid means.

5. An electric heater, comprising: supporting respect to said supporting means, said hook 10 means comprising a plurality of circumferentially spaced depending hooks having jaws for receiving circumferentially spaced portions of said reflector, said jaws all extending in the same general direction.

6. An electric heater, comprising: supporting means; electric heating means mounted upon said supporting means; a reflector; and hook means for carrying said reflector in position below said supporting means, said hook means and said reflector being relatively so constructed and arranged that said refiector may be assembled with and disassembled from said hook means solely by relative movement of said reflector with respect to said hook means generally edgewise with respect to said supporting means, said hook means comprising a plurality of circumferentially spaced depending hooks having jaws for receiving circumferentially spaced portions of said reflector, said jaws all extending in the same gen eral direction, a plurality of said hook having neck portions outside of the outer periphery of said reflector and at least one of said hooks having a neck portion extending through an aperture in said reflector.

EDWIN L. WIEGAND.

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