CA1039021A - Conduction heater and manufacture thereof - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

The disclosure describes a device for the conductive heating and/or cooling of an article. It comprises a metallic casting, a hollow element substantially entirely encapsulated by the casting, opposite end portions of the hollow element being exteriorly exposed by a void in the casting associated with each end portion. Each end portion and associated void are in generally tangential relationship to an exterior surface of the metallic casting.

Description

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This is a divisional application o~ Serial No. 120,044 in the name of Kenneth T. MacMillan filed August 6, 1971 and i~
entitled CONDUCTION HEATER AND MANUFACTUR~ THEREO~.
It is conventional in the recapping and vulcanizing 5 industry to employ annular tire molds or matrice~ which are -generally of an annular configuration de~ined by inner and outer peripheral surface por~ions, the former of which de~ines ~ ~
a mold cavity. The cavit~ is provided with a desired tread ~ .
design such that during a recapping operation, as an example, a tire with camel back thereon when positioned in the cavity ana cured will assume the mirror image configuration of the tread des~gn.
The curing is generally accomplished by passing steam through ports in the matrix or connecting embedded heaters in the matrix to a suitable source of electrical energy. I~, as iæ the usual case~ the ports ofthe matrix are formed by hollow tubes about which as been cast molten metal which subsequently is permitted to solidify, the initial heating o~ the tubes re-~ults in the expansion thereof, and after the curing operation , ~0 col~ water introduced into the tubes results in contraction.
Where the tubes are constructed from, for example, steel and the matrix casing o~ body is formed from aluminum, the difference -in the coef~iclent o~ expansion of these metals results in the ru~t~re of the tubes, and more particularly inlet and outlet

2~ fitments which are conventionally welded to the tube ends. More-over, such relative expansion and contraction can even ~racture the fitments during the molding of the matrices. -~
It is also the present practice in the industry of ~ curing tires and matrices by employing either steam or electricity, 30 and more particularly either by embedding calrod or similar type heaters in the matrix casting or a tube which is adapted for -1~

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-,.~ ~ , -- . -- - 10390Zl connection to a source of steam, hot water or the like. However, at present there are no commercially available matriaes which, at the choice of the user, can be alternatively and ~electively heated by electricity, steam, hot water or a similarly heated medium.
In keeping with the foregoing, it is a primary object of the present invention to provide a novel heater though parti- :
cularly designed as an annular heater plate or matrix for the :
recapping and vulcanizing of tires, is equally applicable for use in other fields. ~he heater may be designed as a frying pan, a percolator or similar heating plate, an electric iron and most any type heater in which a heating element is normally : -cast directly into metal bodies which are to be heated or is .` ~.
insertable in cast metal bodies having appropriate openings to ~
receive the heater elements. .
Another object of the present invention is to provide :~ .
a novel device for the conductive heating and/or cooling of an ~-article which device includes a device for the conductive hea~
ing and/or cooling of an article comprising a metallic casting, a hollow element substantially entirely encapsulated by said casting, a portion of said hollow element being exposed by a -^
void in said casting, and means mounting said hollow element for relative slidin~ movement relative to said casting~ ` -Another object of the present invention is to provide `~ -:
a device for the conductive heating and/or cooling of an article ..
comprising a metallic casting, a hollow element substantially entirely encapsulated by said casting, opposite end portions of said hollow element being exteriorly exposed by a void in said casting associated with each end portion, and each end portion and associated void being in generally tangential relationship to an exterior surface of said metallic casting.
A further object of the present invention is to ., .

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390;21 provide a novel device of the type heretofore mentioned wherein the hollow element is tubular and circular, and the mounting means includes a plurality of sleeves exteriorly surrounding the hollow element and being embedded with the casting.

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Another object of this invention is to provide a novel heater device of the type mentioned wherein terminal end portions of the hollow element are disposed in generally tangentlal rela-tionship to the casting which is of a generally angular configura-tion, and the ends of the hollow element are in a communicatiOnwith atmosphere through tangential voids in the outer peripheral surface of the annular casting.
With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed ~e- ; ~ -scription, the appended claimed subject matter, and the several , . .
viewæ illustrated in the accompanying drawings.

IN THE DRAWINGS:
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Figure 1 is a side elevational view of a mold in which the conductive heater or matrix of the present invention is formed, with portions thereof being shown in section for clarity, and illustrates an annular cavity within which is supported a gen-,:
erally circular hollow tubular element. ~
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; Figure 2 is a top plan view taken along line 2-2 of ....
Figure l, and illustrates a plurality of means moùnting the hollow element for sliding movement relative to the mold cavity, as well as the casting eventually formed therein, and also ; illustrates tangentially disposed ends of the hollow element closed by venting plug5 .
~ Figure 3 is an enlarged fragmentary sectional view -ta~en generally along line 3-3 of Figure 2, and illustrates one of the mounting means in the form of a sleeve exteriorly surround-ing a portion of the hollow element and being supported within the cavity by a removable bolt passed through aperature in the mold and threaded into a nut welded to the sleeve.
Figure 4 is a fragmentary top plan view of the mold .. . . .
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o~ Figure ~, and illustrates a modification wherein the ends of the circular hollow tubular element are radially disposed with res~ect to the mold and are mounted for relative sliding move- ;~
ment by asbestos sleeves housed within radial openings of the mold body.
Figure 5 is a side elevational view of two matrix halves formed in themold of Figures 1 and 2, with portions thereof re- -~oved ior c'larity, and illustrates the manner in which the halves ',, define a matrix cavity in which an article may be heated andlor ''~
cooled by introducing a heated medium into the hollow elements through the expoæed ends or inserting therein a heater adapted ', '~or'connection to a source of electrical energy.
Figure 6 is a fragmentary sectional view taken gener-al~y along line ~-6 of Figure 5, and illustrates the manner in , which fitments are secured to exposed ends of the hollow elements through tangent~al voids or openings ln the outer peripheral suriaoe of each o~ the matrix halve~.
Figure 7 is an enlarged fragmentary sectional view ,, similar to Figure 6, and illustrates a heating element housed ;~
, 20 with~n t~e tubular element with ends thereof exposed for connec-''' -ti~n to a source of e'lectrical energy. ''~
,~ 'Réference is first made to Figures 1 through 3 of the .
~ drawings which illustrate a mold 10 formed by an upper mold half -, , .. . .
11 and a lower mold half 12.
The upper mold half 11 includes a generally circular , ,plate 13 having at its axis a tuhular gate 14 in which molten metal is poured to fill a cavity 15 defined by the lower mold ~' half 12. About the periphery (unnumbered) of the platè 13 of the upper mold half 11 are disposed a plurality of circumferentially spaced tubular risers 16 that feed the casting as it solidifies in a conventional manner. There are six such risers 16 equally . .

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1~390~1 spaced about the periphery of the plate 13, but the number there of may vary depending upon the size, shape, design, etc. of the mold cavity 15. Suitable means (not shown) are connected to tie bars 17 for lifting and lowering the upper mold half 11 relative to the lower mold half 12 which may be conventionally supported on a level floor, table or like support S0 The lower mold half 12 includes a central generally circular core 18 having an axial recess 20 in axial alignment :~
with the axis of the gate 14. Radiating radially outwardly of the recess 20 are six channels 21, each of which is in alignment with one of the risers 16. The channels ~1 open into the cavity 15 which is defined by a generally curved peripheral surface 22 of the core 18, a lower flat annular surface 23 of a ~lange 24 of the core 18, and an inner surface 25 of an outer annular wall 26. --Prior to positioning the upper mold hal$ 11 upon an upper ~ur~ace 27 o~ the outér annular wall 26 in the manner illustrated ~:
. , in phantom outline of Figure 1, a hollow, tubular, generally cir- ~ ;
cular element E is supported interiorly of the cavity 15 by a :~
plurality of identical mounting means, each of which is generally designa~ed by the re~erence numberal 30 in Figures 1 through 3 of the drawin~s. As is best illustrated in Figure 2, the mounting means 30 are spaced from each other about the periphery of the wall 26 and are supported thereby in a manner which will be best under-stood by reference to Figures 2 and 3 of the drawings in particular.
Each of the mounting means 30 includes a hollow annular sleeve 31 to which is welded or otherwise conventionally secured a nut 32 into which is threaded an end portion 33 of a bolt 34 (~'igure 3~. The bolt 34 passes through an opening 35 of the outer :
w&ll 26 and terminates at the exterior thereo~ in a bolt head 36.
The bolt 34 preferably forms a friction fit with the opening 35 so that molten metal introduced into the cavity 15 will be incapable of passing through the space between the bolt 34 and the passage 35 ., .. .

~a3so2l to the exterior of the outer wall 26. As an alternativs,suitable packing or sealing material may be positioned between the bolt 34 and ~he passage 35 to prevent theleakage of molten metal. ;~
A plate 37 constructed from flexible metallic material includes a central opening 38 through which passes the bolt 34.
The bolt head 36 rests against an outer ~ace (unnumbered) of the plate 37. Opposite ends (unnumbered~ of the plate 37 are provided with threaded aperatures (unnumbered) and in each of which is threadably secured an Allen screw 40.
The mounting means 30 and the hollow element E are assembled by first sliding each of the sleeves 31 carrging the nuts 32 upon the hollow element E by merely teles~oping the same over terminal ends 41,42 of the hollow element E. At this time the bolts 34 are not threaded in the nuts 32, and the sleeves 31 are merely slid upon the hollow element E to generally the position thereof illustrated in Figure 2. Thereafter the bolts 34 are inserted through the aperatures 38 of the plate 37 and each pass-age 35 after which each bolt is threaded into an associated nut 32. Thereafter the screws 40 are threaded to the pos~tion shown in Figure 2 to center the hollow element E within the cavity 15 in the manner illustrated in Figures 1 and 2, it being noted at this time that the ends 41,42 are housed within the cavity 15 in generally superimposed rel-ationship to each other. Obviously, if molten metal or similar flowable but solidifiable material were poured into the cavity 15, the same would enter the end portions 41,42 which is obviously undesirable. Therefore, the ends 41,42 are preferably provided with in+ernal threads 43(Figure 6) and threaded into each end portion 41,42 is an externally threaded steel plug 44 having an axial bore 45. The plugs 44 are inserted through tangential bores 46 (Figure 2) in the outer wall 26 and thus place the interior of the hollow element E in fluid communi-cation with atmosphere. Here again the plugs or inserts 44 are ~ .. - . . . .
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103~0Zl preferably in frictional engagement with the surface of the bores 46 to prevent the molten metal from escaping through the bore 46, .
but ii necessary or desirable suitable sealing ma.terial, such as asbestos, may be positioned between the bore 46 and the exterior of the inserts 44 to prevent the escape of the molten metal out-wardly of the cavity 15. As is best illustrated in Figure 2, ends of the inserts 44 pro~ect into the cavity 15 and the axis of each insert 44 is coincident to the axis of the associated end portions 41~42 of the hollow element E.
After the hollow element E has been positioned in the cavity 15 in the manner illustrated in Figure 2, the upper mold half 11 is descended to the phantom outline position shown in Figure 1 and molten metal, such as aluminum, ls poured into the gate 14 and flows through the channels 21 filling the cavity 15 -::
i5 and the risers 16 in a conventional manner. The elevated tem-perature of the molten metal may produce steam or other gases i.nternally of the hollow element E, and these are vented to atmosphere through the passages 45 of the inserts 44. Moreover, .
assuming that the hollow.element`E is formed of steel or any ... ~:
other ~aterial having a coefficient of expansion different from i.
; that~of the aluminum or other molten metal, any relative expan~
, sian andlor contraction of the hollow element E relative to the ,~
metal in the cavity 15, as the latter solidifies, is compensated .for by the sliding movement permitted to the hollow element E
relative to the sleeves 31. Moreover, should the hollow element E expa~d to increase its normal diameter, the bolts 34 are free .`
to move radially outwardly while during contraction of the hollow element E to a diameter less than its original diameter the re-silient nature of the plates 37 permit the same to deflect to an ~ :
outwardly opening bowed configuration thus permitting any con-traction of the hollo~ element E. Moreover, the sleeves 31 are so closely fit upon the hollow element E that the molten metal cannot enter between the exterior surface of the hollow element ::

,!.'. . .' . . ` ' ' ~ . . . ' ,,. ' ~ 39(:~21 and the interior surface o~ each sleeve 31, and upon solidifica-tion of the molten metal relative sliding movement between the hollow element E and each of the sleeves 31 is effected when in use, as will be hereinafter more fully described. To positively assure such sliding movement an ashestos sleeve may be positioned between the tubular element ~ and each sleeve 31 thus preventing the molten metal from flowing between the hollow element E and the sleeves 31 during the casting operation.

.~ ' After the casting has solidified and cooled the u~per mold half 11 is removed and subsequently any excess material, as may have solidified in the riser 16 or the gate 14, is removed iD a conventional manner. However, this is done only after the casting, which is generally designated by the reference numeral 50 in Figure 5, has been removed from the lower mold half 12.
In order to accomplish the removal of the casting S0 from the cavity 15, the bolts 34 are unthreaded from the nuts 32 which, due to the hexagonal outline thereof, are embedded in the casting and cannot rotate. Thus, each bolt 34 may be removed to free each casting from the outer wall 26 with the slee~es 31 and the bolts 32 embedded within the casting 50. Thereafter, the inserts 44, 44 are unthreaded from the end portions 41, 42 of the hollow element E and the outer wall 26, which may be of a sectional construction, i.e., two semi-annular halves, is removed to permit .- .
the removal of the casting 50 from t~e cavity 15 for subsequent finishing and machining, as might be necessary~.

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Reference is now particularly made to Figure 5 wherein two of the cast~ings 50, 50 formed in the mold 10 are illustrated, with the castings being positioned one atop the other to define - a matrix which is generally designated by the reference numeral 51 baving an outer peripheral surface 52 and an inner peripheral sur-face 53 defining a cavity 54 adapted to receive a tire for subse-quent recapping, vulcanizing and the like. The castings 50, 50 I are suitably secured to each other during a recapping operation.

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- la3s~%l ' B~ virtue of the use of the inserts 44, 44 during the molding of the castings 50, the same are provided in the peri-pheries 52 thereof with voids or recesses 55, 56, each of which has an axis in coincidence with the respective end portions 41, 42 of the hollow element E. If, for example, the matrix 51 is to be heated by steam, hot water or similar heated media, a :
nipple 57 is threaded into each of the thread portions 43 of the end portions 41, 42, and steam, hot water, or the like may be .
introduced into and removed from the hollow element E in the manner indicated in Figure 6. However, if instead it is desired to heat the matrix 51 by electrical energy, a conventional ~ ~:
Calrod* 58 is telescoped through the hollow element E and opposite ends thereof 60, 61 are secured to the interior threads 43 of the hollow element end portions 41, 42. Suitable terminals 62, 63 are accessible through the voids 55, 56 for connection to ~ ~
an electrical energy source. `: :
The Calrod* or similar heating element 58 is prefer~
ably provided along its length with a plurality of annular washer-like spacers 64 which prevent the heating element 5~ from actual-ly coming into contact with the inner walls of the hollow metal-lic element E. However, the spacers 64 are provided with sufficient clearance to allow for the heating element 58 to ex- ?
pand and contract. If desired, before the ends 41, 42 are . -closed by the threaded elements 60, 61, the hollow element E may - :
be filled with any good, practical heat transfer agent such as :~
high temperature, nonflammable oil or powdered metal, such as aluminum or powdered graphite. Of course, the liquid would be preferable since it would eliminate any air pockets thereby giving positive heat transfer as well as protecting the heating element 58 from atmosphere and thus eliminating oxidation.
From the foregoing, and particularly a comparison of Figures 6 and 7, it is also to be noted that the castings 50 * trade mark _9_ ~- .

1(~39021 can be readily converted from electrical-type heaters to steam-type heaters merely by interchanging the heater 58 of Figure 7 with the nipples 57 of Figure 6. This convertibility is highly desirable Furthermore, due to the absence of bend8 ~;
in the hollow element E, the heating element 58 can be readily inserted completely through the hollow element ~ after the castings 50, 50 have been formed, and need not be housed in the hOllow element E during the casting operation wherein the elevated temperatures of the molten metal could adversely affect the same.

Though the absence of abrupt bends is an important ~object of constructing the castiDgs 50, 50 in the manner hereto-fore described, reference is made to Figure 4 which illustrates a mold identical to the mold of Fi~ure3! 1 though 3, except in the present case a side wall 66 thereof is provided with radial passages or bores 67, 68 through which project ra~ial terminal ends 70, 71 of another hollow tubular element E'. The end portions 70, 71 are preferably wrapped in a8besto9 or asbe8 tos sleeves 72 to prevent the molten metal from flowing outwardly through the passages 67, 68, as well as to permit the end por-. . .
~ tions 70, 71 to slide radially in the passages 67, 68 during ~ . - , expansion or contraction of the tubular element E'. Further-more, though the end portions 70, 71 are illustrated as integral portions of the circular hollow element ~', the same may be separate pieces or fitments welded to~the hollow element E' at the 00 degree bend thereof. Whereas~such conventionally welded structures might rupture due to expansion and contraction when ; ~ in use, the manufacture of the casting in the manner heretofore described which permits the relative sliding movement due to the , ,~ , .
~;30 sleeves 31 will virtually preclude such rupture at the welds.

~ Thus, though not illustrated in Figures 4 or 5, the hollow ele-! ments ~ and ~' include within the castings 50, 50, the sleeves .:

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31 and the nuts 32 to permit the contraction and expansion ~ere-tofore noted.

While the present invention has been described particu-larly in the manufacture of annular matrices 51 or similar heat-ing devices, the manner in which relative movement of the hollowelement E relative to a casting by virtue of the sleeve 31 being embedded therein may be employed in any type of heating device.
As an example, a mold could be constructed of a generally tri- ;
angular configuration with a like contoured hollow element being ~
disposed therein and supported by comparable mounting means 30. ~-When the casting formed therein has solidified an electrical heater could be installed, as in the case of Figure 7, to use the casting as the base of a conventional electric iron. More-over, by merely mo]ding completely solid circular or rectangular plates one c~uld construct such appliances a hot-plates, per-colator heaters, etc., merely by incorporating therein compar-able electric heating devices, such as the heating device 58.
~owever, in any such case the relative sliding mo~ement provided between the hollow elements and the casting body per se by virtue Of the embedded sleeve ~1 precludes damage irrespective of the dif~erences in coefficients of expansion between the material ~rom which the hollow elements are constructed and the casting material.
'"" ' Though the hollow element E has been described as being ~referably formed of steel while the molten metal introduced into the cavity 15 has been described as aluminum, it is to be under-stoQd that changes in these materials are within the scope of this invention. For example, the hollow elements E may be formed of copper and for that matter need not be constructed from metallic material as also need not the molten material introduced into the cavity 15. Insofar as the present invention is concerned, the . . . _ ~_ :

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hollow elements E may be construoted of most any type material so long as ~e melting point thereof is higher than the melting point of the molten material poured into the mold 15.

While preferred forms and arrangements of parts have been shown in illustrating the invention, it is to be clearly understood that various changes in details and arrangement of parts may be made without departing from the spirit and scope of this disclosure.

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Claims (10)

The embodiments of the invention in which an exclus-ive property or privilege is claimed are defined as follows:-

1. A device for the conductive heating and/or cooling of an article comprising a metallic casting, a hollow element substantially entirely encapsulated by said casting, opposite end portions of said hollow element being exteriorly exposed by a void in said casting associated with each end portion, and each end portion and associated void being in generally tangent-ial relationship to an exterior surface of said metallic casting.

2. The device as defined in Claim 1 wherein said opposite end portions project tangentially outwardly of said metallic casting in opposite directions.

3. The device as defined in Claim 1 including at least one sleeve surrounding said hollow element and being encapsulated by said casting, said sleeve having a threaded bore, a bore in said casting aligned with said threaded bore, said bores being in open communication with each other, and the bore of said casting opening outwardly through a peripheral exterior surface of said casting.

4. m e device as defined in Claim 1 including an electric resistance heater housed in said hollow element.

5. The device as defined in Claim 1 including means for selectively coupling an electric resistance heater or a fluid conducting conduit to at least one of said opposite end portions.

6. The device as defined in Claim 2 including at least one sleeve surrounding said hollow element and being encapsulated by said casting, said sleeve having a threaded bore, a bore in said casting aligned with said threaded bore, said bores being in open communication with each other, and the bore of said casting opening outwardly through a peripheral exterior surface of said casting.

7. The device as defined in Claim 2 including an electric resistance heater housed in said hollow element.

8. The device as defined in Claim 2 including means for selectively coupling an electric resistance heater or fluid conducting conduit to at least one of said opposite end portions.

9. The device as defined in Claim 3 including an electric resistance heater housed in said hollow element.

10. The device as defined in Claim 3 including means for selectively coupling an electric resistance heater or a fluid conducting conduit to at least one of said opposite end portions.