CA1039022A - 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 said hollow element being exteriorly exposed by projecting outwardly through an exterior peripheral portion of the casting. At least one sleeve surrounds the hollow element and is encapsulated by the casting. The sleeve has a threaded bore and there is a bore in the casting aligned with the threaded bore. The bores are in open communication with each other. The bore of the casting opens outwardly through a peripheral exterior surface o-f the casting.

Description

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This application is a division of Serial No.
224,785 filed April 16, 1~75 which, in turn, is a division of Serial No. 120,044 filed April 6, 1971, now patent No.
974,027 S It is conventiQnal in the recapping and vulcanizing industry to employ annular tire molds or matrices which are generally of an annular configuration defined by inner and outer peripheral surface portions, the former of which defines a mold cavity. The cavity is provided with a desired tread design such that duriny a recapping operation, as an example, a tire with camel back thereon when positioned in the cavity ~-and cured will assume the mirror image configuration of the tread design.
The curing is generally accomplished by passing steam throuyh ports in the matrix or connecting embedded heaters in the matrix to a suitable source of electrical energy. If, as is the usual case~ the ports of the matrix are formed by hollow tubes about which has been cast molten metal which subsequently is permitted to solidify, the initial heating of the tubes results in the expansion thereof, and after the curing operation cold water introduced into the tubes results in contraction. Where the tubes are con-, structed from, for example, steel and the matrix casing or i body is formed from aluminum, the difference in the co-efficient of expansion of these metals results in the rupture of the tubes, and more particularly inlet and outlet fitments which are conventionally welded to the tube ends.
Moreover, such relative expansion and contraction can even fracture the fitments during the molding of the matrices.
rt is also the present practice in the industry :
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of curing tires and matrices by employing either steam or electricity, and more particularly either by embedding calrod or similar type heaters in the matrix casting or a tube which is adapted for connection to a source of steam, hot water or 5 the like. However, at present there are no commercially available matrices which, at the chcice of the user, can be alternatively and seIectively heated by electricity, steam, hot water or a similarly heated medium.
In keeping with the foregoing, it is a primary 10 object of the present invention to provide a novel heater though particularly designed as an annular heater plate or matrix for the recapping and vulcanizing of tires, is equally ~ v applicable for use in other fields. The heater may be de-signed as a frying pan, a percolator or similar heating 15 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 pro-20 vide a novel device for the conductive heating and/or cooling of an article which device includes a metallic casting, a hollow element substantially entirely encapsulated by said casting, opposite end portions of said hollow element being exteriorly exposed by projecting outwardly through an exterior 25 peripheral portion of said casting, at least one sleeve sur-rounding 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 30 casting opens outwardly through a peripheral exterior sur-face of said casting.

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A further object of the present invention is to provide a novel device of the type heretofore mentioned wherein the hollow element is tubular and circular r and the mounting means includes a plurality of sleeves exteriorly surrounding the hollow element and being embedded within the casting.
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 aisposed in generally 10 angular configuration, and the ends of the hollow element -~
are in a communication with atmosphere through tangential voids in the outer peripheral surface of the annular casting.
With the above and other objects in ~iew that will hereinafter appear, the nature of the invention wi31 be more clearly understood by reference to the following detailed description, the appended claimed subject matter, and the several views illustrated in the accompanying drawings.
IN THE DRA~INGS:
Figure 1 is a side elevational view of a mold in which the conductive heater or matrix of the present inven-tion is formed, with portions thereof being shown in section -~
for clarity, and illustrates an annular cavity within which is supported a generally circular hollo~ tubular element.
Figure 2 is a top plan view taken along line 2-2 of Figure 1, and illustrates a plurality of means mounting the hollow element for sliding movement relative to the mold cavity, as well as the casting eventually formed therein, and also illustxates tangentially disposed ends of the hollow element closed by venting plugs.
Figure 3 is an enlarged feagmentary sectional view .

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taken generally along line 3-3 of Figure 2, and illustrates one of the mounting means in the form of a sleeve exteriorly surrounding a portion of the hollow element and being sup-ported within the cavity by a removable bolt passed through aperture in the mold and threaded into a nut welded to the sleeve.
Figure 4 is a fragmentary top plan view of the mold of Figure 2, and illustrates a modification wherein the ends `' of the circular hollow tubular element are radially disposed with respect to the mold and are mounted for relative sliding movement by asbestos sleeves housed within radial openings of the mold body.
Figure 5 is a side elevational view of two matrix halves formed in the mold of Figures 1 and 2, with portions thereof removed for clarity, and illustrates the manner in which the halves define a matrix cavity in which an article may be heated and/or cooled by introducing a heated medium into the hollow elements through the exposed ends or insert-ing therein a heater adapted for connection to a source of electrical energy.
Figure 6 is a ~ragmentary sectional view taken generally along line 6-6 of Figure 5, and illustrates the manner in whieh fitments are secured to exposed ends of the hollow elements through tangential voids or openings in the outer peripheral surface of each of the matrix halves.
Figure 7 is an enlarged fragmentary sectional view , similar to Figure 6, and illustrates a heating element housed ', within the tubular element with ends thereof exposed for connection to a source of electrical energy.
Reference is first made to Figures 1 through 3 of ~3~3C)22 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 axi.s a tubular 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 plate 13 of the upper mold half 11 are disposed a plurality of circum-ferentially spaced tubular risers 16 that feed the casting as it solidifies in a conventional manner. There are six such risers 16 equally spaced about the periphery of the plate 13, but the number thereof 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 S. ~;
The lower mold half 12 includes a centrally general-ly circular core 18 having an axial recess 20 in axial align-ment with the axis of the gate 14. Radiating radially out-wardly of the recess 20 are six channels 21, each of whichis in alignment with one of the risers 16. The channels 21 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 flange 24 of the core 18, and an ' 25 inner surface 25 of an outer annular wall 26.
¦ Prior to positioning the upper mold half 11 upon an upper surface 27 of the outer annular wall 26 in the manner illustrated in phantom outline in Figure 1, a hollow, tubular, generally circular element E is supported interiorly o~ the cavity 15 by a plurality of identical mounting means, ~3~0;~2 each of which is ~enerally designated by the reference numeral 30 in Figures 1 throuyh 3 of the drawings. As i5 best il-lustrated in Fi~ure 2, the mounting means 30 aLe spaced from each other about the periphery of the wall 26 and are supported thereby in a manner which will be best understood by reference to ~'igures 2 and 3 o~ the drawings in particular.
Each of the mounting means 30 includes a hollow annular sleeve 31 to which is welded or otherwise convention-ally secured a nut 32 into which is threaded an end portion 33 of a bolt 3~ (Figure 3). The bolt 34 passes through an opening 35 of the outer wall 26 and terminates at the exterior thereof in a bolt head 36. The bolt 34 preferably forms a friction fit with the opening 35 so that molten metal intro-duced into the cavity 15 will be incapable of passing through the space between the holt 34 and the passage 35 to the exter-ior of the outer wall 26. As an alternative, suitable packing or sealing material may be positioned between the bolt 34 and the passage 35 to prevent the lea~age of molten metal.
A plate 37 constructed from flexible metallic mate-rial includes a central opening 38 through which passes thebolt 34. The bolt head 36 rests against an outer face ~un-numbered) of the plate 37. Opposite ends (unnumbered) of the plate 37 are provided ~ith threaded apertures (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 carrying the nuts 32 upon the hollow element E by merely telescoping 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

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1~35~ 2 to generally the position thereof illustrated in Figure 2.
Thereafter the bolts 34 are inserted through the apertures 38 of the plate 37 and each passage 35 after which each bolt is threaded into an associated nut 320 Thereafter the screws 40 are threaded to the position shown in Figure 2 to center the hollow element E within the cavity 15 in the manner il-lustrated 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 relationship 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 internal threads 43 (Figure 6) and threaded into each end portion 41, 42 is an externally threaded steeI plug 44 ha~ing 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 communication with atmosphere.
Here again the plu~s or inserts 44 are preferably in frictional engagement with the surface of the bores 46 to prevent the molten metal from escaping through the bore'46, but if neces-sary o~ desirable suitable sealing material, 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 outwardly of the cavity 15. As is best illustrated in Figure 2, ends of the inserts 44 project 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 hol~ow element'E.
^ After the hollow element E has been positioned in the cavity 15 in the manner illustrated in Figure 2, the :. , ~ . . , . ~ .
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1~3~022 upper mold half 11 is descended to the phantom outline posi-tion shown in Figure 1 and molterl metal, such as aluminum, is poured into the gate 14 and flows through the channels 21 filling the cavity 15 and the risers 16 in a conventional manner~ The elevated temperature of the molten metal may produce steam or other gases internally of the hollow element E, and these are vented to atmosphere through the passayes 45 of the inserts 44. Moreover, assuming that the hollow element E is formed of steel or any other material having a coefficient of expansion different from that of the aluminum or other molten metal, any relative expansion and/or contrac-tion 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 expand to increase its normal diameter, the bolts 34 are free to move radially outwardly while during contrac-tion of the hollo~ element E to a diameter less than its original diameter the resilient nature of the plates 37 per-mit the same to deflect to an outwardly opening bowed con-figuration thus permitting any contraction of the hollow ; 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 E and the interior surface of each sleeve 31, and upon solidification 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 sllch sliding movement an asbestos sleeve may be positioned between the tubular el`ement E and each-~ .

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sleeve 31 thus preventing the molten metal from flowingbetween the hollow element E and the sleeves 31 during the casting operation.
After the casting has solidified and cooled the upper mold half 11 is removed and subsequently any excess material, as may have solidified in the riser 16 or the gate 14, is removed in 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 50 from the cavity 15, the bolts 34 are unthreaded f~om 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 castin~ from the outer wall 26 with the sleeves 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 the cavity 15 for subsequent finishing and machining, as might ;~
be necessary.
Reference is now p-articularly made to Figure S
~herein two of the castings 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 having an outer peripheral surface 52 and an inner peripheral surface 53 defining a cavity 54 adapted to receive a tire for subsequent recapping, vulcaniz-; 3Q ing and the like. The castings 50, S0 are suitably secured .

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to each other during a recapping operation.
By virtue o~ the use of the inserts 44, 44 during the molding of the castings 50, the same are provided in the peripheries 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 i.ndicated 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 58 from actually coming into contact with the inner walls of ~he hollow metallic element E. However, the spacers 64 are provided with sufficient clearance to allow for the heating element 58 to expand 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 trans-fer 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 elimin-ate any air pockets thereby giving positive heat transfer * trade mark - ., . , .

1~)3~0;22 as well as protecting the lleating 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 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 bends in the hollow element E, the heating element 58 can be readily inserted completely through the hollow element E after the castings 50, 50 hav 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 castings 50, 50 in the manner heretofore described, reference is made to Figure 4 which illustrates a mold identical to the mold of Figures 1 through ~-

3, except in the present case a side wall 66 thereof is pro~
vided with radial passages or bores 67, 68 through which project radial termin~l ends 70, 71 of another hollow tubular element E'. The end portions 70, 71 are preferably wrapped in asbestos or asbestos sleeves 72 to prevent the molten !~
metal from flowing outwardly thorugh the passages 67, 68, as well as to permit the end portions 70, 71 to slide radially in the passages 67, 68 during expansion or contraction of the tubular element E'. Furthermore, though the end portions .: .
70, 71 are illustrated as integral portions of the circular ~ .
hollow element E', the same may be separate pieces or fitments :

welded to the hollow element E' at the 90 degree bend thereof.
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1~P3~2 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 per-mits the relative sliding movement due to the sleeves 31 will virtually preclude such rupture at the welds. Thus, though not illustrated in Figures 4 or 5, the hollow elements E and E' include within the castings 50, 50, the sleeves 31 and the nuts 32 to permit the contraction and expansion hereto-fore noted.
While the present invention has been described particularly in the manufacture of annular matrices 51 or similar heating devices, the manner in which relative move-ment of the hollow element E relative to a casting by virtue of the sleeve 31 being e~bedded therein may be employed in any type of heating device. ~s an example, a mold could be constructed of a generally triangular configuration with a like contoured hollow element being disposed therein and suppoxted 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. Moreover~ by merely molding completely solid circular or rectangular plates one could construct such appliances as hot-plates, percolator heaters, etc., merely ky incorporating therein comparable electric heating devices, such as the heating device 58.
~owever, in any such case the relative sliding movement pro-vided between the hollow elements and the casting body per se by virtue of the embedded sleeve 31 precludes damage irre-spective of the differences in coefficients of expansion between the material from whichthe hollow elements are con-structed and the casting material.

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Though the hollow element E has been described as being preferably formed of steel while the molten metal intro-duced into the cavity 15 has been described as aluminum, it is to be understood 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 ~hat matter need not be constructed from metallic material as also need not the molten material intorudced into the cavity 15. Insofar as the present invention is concerned, the hollow elements E may be constructed of most any type material so long as the melting point thereof is higher than the melting point of the molten material poured into the mold 15.
~hile prefer.red orms and arrangements of parts have been shown in illustrating the. invention, it is to be clearly lS 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 (3)

The embodiments of the invention in which an exclusive 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 projecting outwardly through an exterior peri-pheral portion of said casting, at least one sleeve sur-rounding 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 opens outwardly through a peripheral exterior surface of said casting.

2. The device as defined in Claim 1 including an electric resistance heater housed in said hollow element.

3. 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.