US 2976387 A
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IIIIIIIILIIIII IIIIII/ D. W. BROWNE HEATER BAND Filed May 28, 1958 Illlllll March 2l, 1961 INVENTOR. O ndaZ/mwne,
United States Patent1A HEATER BAND Donald w. Browne, Des Plaines, In., assigner-t Aem Electric'Corporatioma corporation of Illinois FiledI May 28, 1958, Ser. No. 738,363
1 Claim? (Cl. `21919) Thisinven'tionrelates' to heater bands and in particular to heater bands 'utilizingelectric'al heating elements.
In oneform of electrical heater band, the heating element is disposed between sheets of insulating material to effect the .necessary electricalV insulation thereof. The assembly of the heating element and juxtaposed insulating sheets is enclosed in a protective sheath which conventionally is formed of a rigid material such as metal. A problem arises in such heater band constructions; namely, lateral displacement of the heating element sometimes occurs, permitting the heating element to contact the metal sheath and, as a result, have portions thereof shorted out.
The principal feature of this invention is the provision of a new and improved heater band construction arranged to preclude undesired lateral translation of the heating element therein.
Another feature is the provision of such a heater band construction having new and improved means for reducing the spacing between the insulating sheets at a point laterally of the heating element, thereby to preclude such undesirable `lateral translation.
A further feature is the provision of such a heater band construction wherein a portion of the sheath structure projects toward an opposed portion thereof to effect a desired reduced spacing therebetween, said portion being disposed laterally of the heating element.
Still another feature is the provision of such a heater band construction wherein the sheath comprises a support portion and a cover portion, and the projecting portion comprises a depression formed in the sheaths.
A still further feature is the provision of such a heater band construction having a pair of transversely spaced heating elements, and including means for reducing the spacing between the insulating sheets laterally between said elements to preclude undesirable translation of the heating elements such as would result in contact of one element with the other.
Other features and advantages of this invention will be apparent from the following description taken in connection with the accompanying drawings wherein:
Fig. l is a fragmentary elevation of a portion of a heater band construction embodying the invention, with portions thereof broken away; p
Fig. 2 is an enlarged transverse section thereof taken approximately along the line 2-2 of Fig. 1;
Fig. 3 is la reduced, fragmentary elevation of another form of the invention, with portions thereof broken away; and
Fig. 4 is an enlarged, transverse section taken approximately along the line 4-4 of Fig. 3.
In the exemplary embodiment of the invention, asV disclosed in Figs. l and 2 of the drawing, a heater band construction generally designated is shown to comprise a pair of elongated electrical heating elements 11 and 12 disposed between a pair of insulating sheets 13 and 14. The assembly of heating elements and insulating sheets is enclosed by an outer protective sheath 15 each heating element is substantially lless than one-half the width of insulating sheets 13 and 14 whereby the heating elements may be transversely spaced relative to each other between the insulating sheets. sheets 13 and 14 are formed of an electrically insulating material, such as mica, and extend transversely to adjacent the longitudinal edges of sheath 15. Thus, in ad`v dition to faciallyoverlying and underlying heating elements 11 and 12, the insulating sheets 14 and 13 extend laterally of the heating elements to define mid-portions 13a and 14a and side portions 13b and 14b, respectively.
Support member 16 of sheath 15 is provided with discontinuous oveiturned flange portions v18 disposed along each of the opposite longitudinal edges thereof. The side margin portions 19 of cover member 17 underlie flanges 18 and are urged thereby against the upper surface of lateral side portions 14b of insulating sheet 14. Thus, flanges 18 retain the elements of heater band construction 10 in assembled relationship.
To preclude positively inadvertent lateral translation of heater elements 11 and 12 which could otherwise result in a shorting out of the heating elements by their contact with sheath support member 16 or their shorting out with one another, means are provided to effect a positive decrease in the spacing between insulating sheets 13 and 14 at the mid-portions and side portions thereof. These means comprise a plurality of projecting portions 20 on sheath 15, herein on cover member 17 thereof, which extend toward the opposed sheath portion, herein confronting portions of the support member 16, to apply pressure to localized areas of the insulating sheet midportion and side portions and reduce the spacing between said mid-portion and side portions to less than the thickness of the heating elements. As best seen in Fig. 2, projecting portions 20 comprise indentations, or dimples, in cover member 17 and may extend sufhciently toward support member 16 to effect substantial abutment of the confronting portions of the insulating sheets. A plurality of such projections 20 is provided in midportion 21 of cover member 17 overlying mid-portions 14a and 13a of the insulating sheets to provide a plurality of localized pressure areas spaced longitudinally of the heater band construction. A11 additional plurality of projections 20 is provided in the side margin portions 19 of cover member 17, one each between each pair of flanges 18. The projections 20 may be formed in cover member 17 prior to its installation over insulating sheet 14, and the completion of the assembly of the heater band construction effected by the overturning of flanges 18. Alternatively, the cover member 17 may be installed without the depressions 20 and flanges 18 overturned to secure the assembly of the heater band construction, the depressions 20 being then formed in the cover member by subsequent suitable pressure applications to the cover member.
Thus, heater band construction 10 provides improved positive means for precluding undesired lateral translation of the heating elements thereof in an extremely simple and foolproof manner.
Turning now to Figs. 3 and 4, a single circuit heater band construction generally designated 30 is shown to comprise structure similar to that of heater band construction 10 except that only a single heating element 31 is provided. Heating element 31 is arranged to extend intermediate the edges of heater band construction Patented Mar. 21, 1961 Insulating 30 and, thus, no projections are provided in the midport-ion thereof. In all other respects, the structure and functioning of heater band construction 30 is substantially identical to that of. heater band',constructinj10.`
While I have shown and described certainfenibodif nents of myinvention, it is to be,'understoo'd that it is capable ofv rnany modifications'. Changes, therefore, in the construction `and arrangement may be made without departing from the spiritand scope of the invention as defined in the appended claim. i
u Il claim: Y A Vheater band construction comprising: a generally at. heater element; a pair of ,insulating sheetsxijuxta-` posed to opposite sides of said heater element 'and exf tending laterally therefrom; a support sheet facially'juxtaposed to one of said sheets. and having discontinuous overturned edges overlying portions'. of .said vsheets lat-v erallyof said heater element; a cover sheet faciallyjuxtaposed to the other of said sheets and extendingto between said overlying edges and said lateral portions of said other of said sheets; and means associated with at least one yof said support and cover sheets providing a localized pressure on points of said sheets laterally of of said edges.
References Cited in the le of this patent UNITED STATES PATENTS 1,642,197 Fowler. Sept. 13, 1927 1,994,759 Dermott Mar. 19, 1935 2,545,653 Desloge Mar. 20, 1951 2,592,549 Ekstrand et al. Apr. 15, 1952 2,791,624 Kigler May 7, 1957 2,795,685 Browne n June 11, 1957 2,817,742 Drugma'nd Dec. 24, 1957 20 2,849,582 Vander Perk 'Aug. 26, 1958 FOREIGN PATENTS 676,655 1952 Great Britain July 30,