US2413478A

US2413478A - Electric heater

Info

Publication number: US2413478A
Application number: US408073A
Authority: US
Inventors: Edwin L Wiegand
Original assignee: Edwin L Wiegand Co
Current assignee: Edwin L Wiegand Co
Priority date: 1941-08-23
Filing date: 1941-08-23
Publication date: 1946-12-31
Anticipated expiration: 1963-12-31

Description

Dec. 31, 1946. E. L. WIEGAND 2,413,478

ELECTRIC HEATER Filed Aug. 25, 1941 2 Sheets-Sheet l W//\/ L. VV/EGHND INVENTOR ATTORNEYS 7 ,4 "f/ BY W I Dec. 31, 1946. E, w|EGAND 2,413,478

ELECTRI C HEATER Filed Aug. 23, 1941 2 Sheets-Sheet 2 4550 10 7 2'? 2.43 2

\NVENTQR BY www- ATTO R N E15 Patented Dec. 31, 1946 ELECTRIC HEATER Edwin L. Wiegand, Pittsburgh, Pa., assigncr to Edwin L. Wiegand Company,

Pittsburgh, Pa.,

a corporation of Pennsylvania Application August 23, 1941, Serial No. 408,073

13 Claims. 1

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.

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:

Figure l is a plan view of an electric range unit illustratin 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,

Figure 6 is a fragmentary sectional view corresponding generally to the line ii6 of Figure 5, and

Figure '7 is an enlarged sectional view corresponding generally to the line 1-7 of Figure 5.

The electric heater or range unit embodying my invention may comprise one or more heating elements, in this instance two elements It) and H. As herein shown, each element comprises a tubular metal sheath within which is disposed electrical resistance heating means l2, embedded in refractory electrical-insulating heat-conducting material l3. The insulatin material l3 may be in the form of suitable granular, comminuted, or powdered refractory material, preferably compacted to a dense hard condition.

Each of the elements 10 and l I 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 H 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 [0. Therefore, the element H has portions disposed side-by-side, and then has portions disposed side-by-side with portions of the element Hi. This particular construction makes possible a distribution of heat not attainable with structures of the prior art.

For example, assuming that the elements l0 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 ele- 1 respectively numbered l4,

ments herein shown are designed to provide 2000 watts when both are simultaneously energized. The element II 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 is so designed that when it only is energized, it will provide 600 watts. of course, the wattages will be in relation to the voltage used, and in the embodiment it is possible to have other heats. For instance, if 110 volts were used, the elements it and I i herein disclosed are so designed 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 150 watts. Also, it will be apparent that it is possible to employ a switch connected to diiierent 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 It has end portions pi, p2, and the element H has end portions 503, p4. Each of the end portions terminates in a connection terminal, l5, l8, and I7, which may be housed in a suitable insulating block or housing [8. The terminals l5 and I6 are here shown bridged by a bridge plate 19, 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 :01, m, 213, 504 are all of substantially circular or rounded section, to facilitate bending, and preferably only the spiral portions of the elements are of triangular section. The

I elements such as may be embodied in the range unit herein shown may initially comprise a tubular sheath of substantially circular cross-section into which the resistor and insulating 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 co-pending application Serial Number 361,997, filed October 21, 1940. Accordingly, the active portion of each heating element 110 or II comprises a tubular sheath havin two

walls

20, 2|, the major portions of which are fiat and make between them an angle of approximately these walls merging in a rounded apex 22. The upper wall 23 is substantially entirely flat and makes with the

walls

20, 21 angles of 60 respectively. In the embodiment shown, the flat portions of the

walls

20, 2| are respectively of 3 less cross-sectional extent than the substantially entirely fiat 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 Ill, I I, 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 larg area of the heating means, so as to be heated mainly by conduction. The generally downwardly facin lower walls 25, 2I 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 generally underlies the heating elements I0, I I.

The end portions 211, p2, 233, p4 extend downwardly from their respective active portions, and then have their respective extremities bent slightly upwardly toward the insulating block I8, thus forming a drip point 25, best shown in Figure 5 with reference to the portion 173. 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 p3 of the element II, it will be seen that the portion pa extends toward the center of the range unit, upwardly to the active portion, and the active ortion is wound about itself at the center at least once, as shown at 725, and then has, an intermediate portion pa spiralling to the end portion 294. The element I0 starts with the end portion p1 extending upwardly to its active portion, and this active portion is intercalated with respect to the active portion of the element Ii, except at the central portion 105, and terminates in the end portion 112.

The apeXes 22 of the heating elements ll] 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 to 32 inclusive. In the embodiment shown, the supporting means 23 comprises a straight sheet-metal member, pro- Viding the arms 2i, 28. The

arms

29, 33 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 sheetmetal member bent so as to form a central generally U-shapedbight 3A, and the arms 3I, 32 extend from this bight in generally V-shaped relation with respect to each other. The bights 33, Mare fastened to opposite sides of the sheetmetal member forming the

arms

21, 28, as by means of rivets 35. If desired, all, or certain 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 It, II in desired assembly with the supporting means 25. In the embodiment shown, this means comprises a plurality of slots 31 formed in the arm 21, each slot generally underlying the section of the respective heating elements traversed by the arm 21, as best seen in Figure 5. A plurality of clips 38 are secured to the apex of each element Ill, II adjacent the arm 21, as by spot welding, each 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 II], I I are held against substantial movement toward or away from the supporting means 26. 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 2'! 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 40 fitting into an aperture ll in a bracket 52. The bracket 42 is longitudinally curved, as best seen in Figure l, and at its lower extremities is provided with fingers 43 extending inwardly of the range unit, and terminating in upwardly directed ledges M. An upper side margin of the bracket 42 has an angular extension 45 upon which the apex of the element I0, adjacent the end portion 112, rests, thus supporting this part of the element IE3, since it is spaced a substantial distance from the arm 32. The lower margin of the bracket 52 is formed with a curved recess G6 (see Figure 6) to pass the adjacent parts of the end portions 101, :02, pa, in, and the adjacent parts of the end portions 01, n bear against the defining margin of the recess it for the purpose of steadying and aiding in the support of the heating elements I0, II. A ground screw l! is threaded into a tapped aperture formed in the bracket 42, and is adapted to receive a conductor which 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 48, having a cylindrical portion 49 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, 30, and 32 are longer than the other arms, and the longer arms are provided with projections 52 forming shoulders with the 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 25. The arm 21, adjacent its extremity, is provided with a downwardly extending hook 5t. As here shown, the hook is a separate piece and is spot welded to the arm 21. The hook 54 has an inclined surface 55 terminating in a hook-tip 56.

The reflector 24 is disposed beneath the supporting means 25, 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 toward the supporting means 25. The peripheral margin of the reflector 25 is formed with a downwardly ofiset curved portion 51, and the reflector, in line with the hook 54, 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 pocket extending radially inwardly, and merging with the reflector wall adjacent a central opening 50 formed in the reflector 24. On either sid of the pocket 59, the reflector wall is formed with upwardly pressed areas GI, positioned so that the recess surfaces thus formed are adapted to receive respective ledges 44. The hook 54 and the ledges 44 provide hanger means from which the reflector is adapted to be hung,

The reflector 24 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 24 with the supporting means 26, the reflector 24 is moved in a direction generally parallel to the bottom edges of the arms 21 to 32 so that the pocket 59 moves to cover the adjacent parts of the end portions p1, 1 2, p3, and p4, and the reflector is moved a distance sufiicient to align the slot 58 with the hook 54, 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 El align with respective ledges 44. At this time, the reflector is permitted to hang, with the recess surfaces of the 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 55 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 24 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 60, 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 63 rests on the upper edges of the arms 27 through 32, adjacent the

bight portions

33, 34, and has marginal extensions, forming four legs 64, which are secured to the side surfaces of the

bight portions

33, 34 in any suitable manner, as for instance by spot weldmg.

From th 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: supporting means; heating means mounted upon said supporting means, and crossing a part of said supporting means more than once; and holding means, disposed at each of the places where said heating means crosses said part, holding said heating means assembled with said supporting means, each of said holding means comprising a slot and tongue connection between said heating means and said supporting means, each of the slots being larger than it respective tongue to permit relative movement between said heating means and said supporting means so as to accommodate for expansion and contraction of said heating means.

2. An electric heater, comprising: supporting means; heating means mounted upon said supporting means; and holding means, comprising a slot and tongue connection between said heating means and said supporting means, said slot receiving said tongue and being larger than said tongue to permit movement of said heating means in the plane of said supporting means to accommodate for longitudinal expansion and contraction of said heating means, and said tongue being formed to hold said heating means against substantial movement toward or away from said supporting means.

3. An electric heater, comprising: electric heating means, having portions disposed in side-byside relation; supporting means, supporting said electric heating mean-s, and including an arm traversing said portions of said heating means; and holding means, comprising slots in said arm and a clip on each of said portions, each of said clips comprising a tongue passing through a respective slot and having its extremity bent to hold its respective heating means portion against said arm, each of said slots being wider than its respective clip to permit its respective portion to shift along said arm to accommodate for expansion and contraction of said heating means.

4.An electric heater, comprising: supporting means including grid means and ring means connected to and circumscribing said grid means; electrical heating means resting freely on said grid means and having terminal portions extending downwardly through said grid mean and laterally outwardly under the lower margin of said ring means; said grid means and said heating means having mutually engaging surface means so constructed and arranged that said heating means is free to expand and contract by sliding on its places of engagement with said grid means; lost motion connection means between said heating means and said grid means for preventing substantial movement of said heating means away from said grid means at said connection means while permitting said sliding movement, said connection means being disposed approximately diametrically opposite said terminal portions; and means supported by said supporting means, engaging at least one of said terminal portions at a laterally extending portion thereof, constructed and arranged to position said heating means laterally with respect to said ring means at said terminal portions.

5. An electric heater, comprising: supporting means including grid means and ring means connected to and circumscribing said grid means; electrical heating means resting freely on said grid means and having terminal portions extending downwardly through said grid means and laterally outwardly under the lower margin of said ring means; said grid means and said heating means having mutually engaging surface means so constructed and arranged that said heating means is free to expand and contract by sliding on its places of engagement with said grid means; lost motion connection means between said heating means and said grid means for preventing substantial movement of said heating means away from said grid means at said connection means while permitting said sliding movement, said connection means being disposed approximately di- QAISA'YS at said terminal portions.

6. An electric heater, comprising: supporting means including grid means and ring means connected to and circumscribing said grid means; electrical heating means resting freely on said grid means and having terminal portionsextending downwardly through said, grid means and laterally outwardly under the lower margin of said ring means; said grid means and said heating means having mutually engaging surface means so constructed and arranged that said heating means is free to expand and contract by sliding on its places of engagement with said grid means; lost motion connection means between said heating means and said grid means for preventing substantial movement of said heating means away from said grid means at said connection means while permitting said sliding movement, said connection means being disposed approximately diametrically opposite said terminal portions; and means supported by said supporting means, extending downwardly below said ring means and engaging at least one of said terminal portions at a laterally extending por-- tion thereof, constructed and arranged to keep said heating means in substantial engagement with said grid means at said terminal portions and to position said heating means laterally with respect to said ring means.

7. An electric heater, comprising: supporting means including grid means and ring means connected to and circumscribing said grid means; electrical heating means resting freely on said grid means and having terminal portions extending downwardly through said grid means and laterally outwardly under the lower margin of said ring means; said grid means and said heating means having mutually engaging surface means so constructed and arranged that said heating means is free to expand and contract by sliding on its places of engagement with said grid means; and lost motion connection means between said heating means and said grid means for preventing substantial movement of said heating means away from said grid means at said connection means while permitting said sliding movement, said connection means being disposed approximately diametrically opposite said terminal portions; a reflector disposed below said grid means; and a plate supported by said supporting means, engaging at least one of said terminal portions at a laterally extending portion thereof, constructed and arranged to position said heating means laterally with respect to said ring means at said terminal portions, said plate having at least one second projection interengageable with said reflector to support said reflector at aid second projection.

8. An electric heater, comprising: supporting means including grid means and ring means connected to and circumscribing said grid means; electrical heating means resting freely on said grid means and having terminal portions extending downwardly through said grid means and laterally outwardly under the lower margin of said ring means; said grid means and said heating means having mutually engaging surfac means 'so constructed and arranged that said heating means is free to expand and contract by sliding on its places of engagement with said grid means; lost motion connection means between said heating means and said grid means for preventing substantial movement of said heating means away from said grid means at said connection means while permitting said sliding movement, said-connection means being disposed approximately diametrically opposite said terminal portions; a reflector disposed below said grid means; and a plate supported by said supporting means, extending downwardly below said ring means and engaging at least one of said terminal portions at a laterally extending portion thereof, cons'tructedand arranged to keep said heating means in substantial engagement with said grid means at said terminal portions, said plate having at least'one second projection interengageable with said reflector to support said reflector at said second projection.

9. An electric heating unit, comprising: a tubular electric heating element, having approximately its active portion conformed into a pattern defining a surface; a reticulated support, constructed and arranged to have said pattern portion engaged thereagainst on one face'of said pattern portion, and thus to hold said element against displacement in the one direction; and bar and recess means, having one complementary part secured to said support and the other complementary part secured to said active portion, constructed and arranged to permit rela tive movement between said parts in a direction approximatel parallel to said surface, connecting said element to said supporting means at a plurality of places in said pattern, operating to hold said pattern portion toward said support, and thus to hold said element against movement in the opposite direction, but permitting translatory movement of said element relative to said support, thus providing for expansion and contraction of said element under heating and cooling thereof.

10. An electric heating unit, comprising: a plurality of tubular electric heating elements, having approximately their active portions conformed into a pattern defining a surface; a reticulated support, constructed and arranged to have said pattern portions engaged thereagainst on one face of said pattern portions, and thus to hold said elements against displacement in the one direction; and bar and recess means, having one complementary part secured to said support and the other complementary part secured to said active portions, constructed and arranged to permit relative movement between said parts in a direction approximately parallel to said surface, connecting said e ements to said supporting means at a plurality of p aces in said pattern, operating to hold said pattern portions toward said support, and thus to hold said elements against movement in the opposite direction, but permitting translatory movement of complementary part secured to said support and the other complementary part secured to said active portion, constructed and arranged to permit relative movement between said parts in a direction approximately parallel to said plane, connecting said element to said supporting means at a plurality of places in said pattern, operating to hold said pattern portion toward said support, and thus to hold said element against movement in the opposite direction, but permitting translatory movement of said element relative to said support, thus providing for expansion and contraction of said element under heating and cooling thereof.

12. An electric heating unit, comprising: a plurality of tubular electric heating elements, having approximately their active portion conformed into a pattern defining approximately a plane; a reticulated support, constructed and arranged to have said pattern portions engaged thereagainst on one face of said pattern portions, and thus to hold said elements against displacement in the one direction; and bar and recess means, having one complementary part secured to said support and the other complementary part secured to said active portions, constructed and arranged to permit relative movement between said parts in a direction approximately parallel to said plane, connecting said elements to said supporting means at a plurality of places in said pattern, operating to hold said pattern portions toward said support, and thus to hold said elements againstmovement in the opposite direction, but permitting translatory movement of each of said elements relative to said support, thus providing for expansion and contraction of said elements under heating and cooling thereof.

13. An electric heating unit, comprising: a tu bular electric heating element, having approximately its active portion conformed into a pattern defining a surface; a reticulated support, constructed and arranged to have said pattern portion engaged thereagainst on one face of said pattern portion, and thus to hold said element against displacement in the one direction; and bar and recess means, having one complementary part secured to said active portion and the other complementary part secured to said support, respectively, constructed and arranged to permit relative movement between said parts in a direction approximately parallel to said surface, connecting said element to said supporting means at a plurality of places in said pattern, operating to hold said pattern portion toward said support, and thus to hold said element against movement in the opposite direction, but permitting translatory movement of said element relative to said support, thus providing for expansion and contraction of said element under heating and cooling thereof.

EDWIN L. WIEGAND.