Abstract:
A protective collar for a kiln that has a rigid body portion and a shape and size substantially corresponding to the shape and size of at least a portion of the peripheral edge surface of the kiln sidewall. Depending on the kiln, the protective collar can be round, oval, faceted, or otherwise shaped. The collar can be a complete ring or just a portion thereof. A plurality of stops, which can be fixed or pivoting, spaced along the body portion of the protective collar can prevent dislocation of the collar when applied to the kiln. The stops can be adjustable in location to avoid obstructions on the kiln. A properly selected protective collar can enable a method for protecting the firebrick in a kiln where the protective collar is applied with the shapes of the protective collar and the peripheral edge surface of the kiln sidewall substantially aligned.

Description:
PRIORITY 
     This application claims priority to Provisional Patent Application No. 61/010,195, filed Jan. 7, 2008. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to kilns. More particularly, disclosed and protected herein is a protective collar for kilns that prevents wear and damage to the upper peripheral edge surface of the kiln during loading and unloading. 
     BACKGROUND OF THE INVENTION 
     Kilns are essential to the manufacture of ceramics, which, by definition, require high temperature treatment. During the firing stage, chemical and physical reactions occur that permanently alter the material. Proper firing of clay converts the relatively weak and malleable substrate into a rigid and strong structure. The final material characteristics of articles of ceramic are determined by a number of factors, including the preparation and composition of the clay substrate, the temperature at which it is fired, and any glazing that might be applied thereto. 
     One type of kiln often used by finished ware manufactures to fire ceramic products is commonly referred to as a hobby kiln, which can be used for firing, curing, and heat treating. Kiln styles include the chamber raise kiln, the top loading kiln, and the front loading kiln. The chamber raise kiln is often referred to as a top hat kiln since an upper body portion with sides, a top, and an open bottom is raised and lowered by a winch system relative to a support surface for enabling the insertion, heat treatment, and removal of articles. A front loading kiln typically comprises a box shape with a vertically hinged front door. 
     Top loading kilns are perhaps the most common type of hobby kiln. A typical top loading kiln is indicated generally at  10  in  FIG. 1 . The top loading kiln  10  has a body portion formed by a fixed peripheral sidewall  12  and a bottom  25 . The sidewall  12  and the bottom  25  together define a firing chamber  16  for receiving articles to be heat treated. A lid  14  with a handle  32  is coupled to the sidewall  12  by a hinge arrangement  18 . The lid  14  can be retained in an open disposition by a support bar  22  or other means. When closed, the lid  14  seals off the chamber  16  to enable proper heating of the kiln  10 . 
     The sidewalls  12  of top loading kilns  10  can be of a variety of shapes, including round as in  FIG. 4 , square, oval, or faceted, such as by having from five to twenty or even more facets. For example, the kiln  10  in  FIG. 1  is faceted with ten sides while the kiln  10  in  FIG. 3  is faceted with eight sides. The thickness T of the sidewalls  12  can vary, but is commonly 2 and ½ to 3 and ½ or more inches. Similarly, the effective inner diameter D of kilns  10  varies depending on, among other things, the needs and budget of the artisan and the design of the manufacturer. 
     Electric heating elements  20 , often made from resistance wire, are disposed in grooves  21  on the interior surfaces of the sidewalls  12 . The kiln  10  receives power through a power cord  30 . Other kilns  10  are gas fired. A control box  24  with a control panel  28  enables control over the operation of the kiln  10 , and a plurality of venting louvers  26  enables heat to be dissipated from the control box  24 . The sidewall  12 , lid  14 , and bottom  25  of the kiln  10  are typically formed by blocks of firebrick, which can be dry fit or cemented together. The firebrick can be enveloped in a metal lining. 
     Firebrick is a refractory ceramic material built primarily to withstand high heat and to demonstrate low thermal conductivity, which saves energy and facilitates sustained high internal operating temperatures. In that regard, it will be noted that kilns  10  are fired not just to a temperature, but to what are typically referred to as cone levels, which account for time and temperature. The firebrick used in electric and gas-fired kilns  10  is often relatively porous thereby rendering the brick lighter, easier to form, and better thermal insulators than denser brick. 
     The sidewall  12  of the top loading kiln  10  has an upper peripheral surface  15  that is flat and horizontal for providing a good seal relative to the lower surface of the lid  14 . A tight seal is important for a number of reasons, including for energy efficiency and to enable the kiln  10  to reach desired cone levels. Furthermore, a good seal will help prevent caustic fumes from escaping from the firing chamber  16  and causing adverse effects on bystanders and surrounding components of the kiln  10 . Furthermore, certain kilns  10  rely on a tight seal to permit a negative pressure to be created by a downdraft vent system that, when installed and operational, limits the emission of fumes by evacuating them from the chamber  16  and exhausting them. 
     Unfortunately, while advantageous for its thermal and other properties, firebrick is very fragile. As such, the soft brick is vulnerable to chipping, breaking, and general wear. For example, as artisans repeatedly lean against the sidewalls  12  to reach into the firing chamber  16 , the firebrick at the upper peripheral edge surface  15  is often worn down over time and otherwise damaged. Furthermore, articles, such as ceramic structures and kiln furniture, can accidentally strike and damage the upper edge surfaces  15  of the sidewalls  12  while being inserted and removed. Further risk of damage and wear comes from the habit of some practitioners of propping the lid  14  of their kiln  10  open by placing a brick or other obstruction between the lid  14  and the upper edge surface  15  of the sidewall  12 . 
     Over time, therefore, a wearing away of the upper peripheral edge surface  15  leads to chips  36  and damaged edge portions  34 . The integrity of the seal between the lid  14  and the upper peripheral edge surface  15  can be compromised, particularly where the damage extends entirely from the inner edge to the outer edge of the upper peripheral edge surface  15 , thereby leading to reduced performance and potential harm to surrounding persons and structures. While repair of the damaged peripheral edge surface  15  is possible, it is expensive and inevitably decreases the life and value of the kiln  10 . 
     With an awareness of the problems and dangers deriving from such damage to the upper peripheral edge surfaces  15  of kilns  10 , it has been appreciated by the present inventor that a structure and method for protecting a kiln  10  during loading and unloading would represent a useful advance in the art. 
     SUMMARY OF THE INVENTION 
     The present inventor set forth with the basic object of providing a protective collar for kilns that prevents wear and damage in relation to the upper surface of the kiln. 
     A related object of the invention is to provide a protective collar for kilns that increases the useful life of the kiln and reduces the need for repairs thereto. 
     A further object of embodiments of the invention is to provide a protective collar for kilns that enables a tight seal between the lid and the upper surface to be maintained thereby improving energy efficiency and firing quality while preventing the deleterious effects of escaping gasses. 
     Another object of the invention is to provide a protective collar for kilns that permits full or substantially full dimensional access to the firing chamber for loading and unloading while protecting the fragile firebrick at the upper surface of the kiln. 
     Still another object of the invention is to provide a protective collar for kilns that reduces the care and attention required in leaning over the kiln thereby improving comfort and ease while saving precious time in loading and unloading articles relative to the kiln. 
     These and in all likelihood further objects and advantages of the present invention will become obvious not only to one who reviews the present specification and drawings but also to those who have an opportunity to observe an embodiment of the protective collar for kilns disclosed herein. However, it will be appreciated that, although the accomplishment of each of the foregoing objects in a single embodiment of the invention may be possible and indeed preferred, not all embodiments will seek or need to accomplish each and every potential advantage and function. Nonetheless, all such embodiments should be considered within the scope of the present invention. 
     In carrying forth the foregoing objects, one embodiment of the invention for a protective collar for a kiln that has a peripheral kiln sidewall with a peripheral edge surface of a given shape, size, and thickness comprises a rigid body portion with an upper surface, a lower surface, an inner edge, an outer edge, and a shape and size substantially corresponding to the shape and size of at least a portion of the peripheral edge surface of the kiln sidewall. It is clear, therefore, that the shape and size of the body portion of the protective collar will vary depending on the shape and size of the sidewall of the kiln to be protected. Consequently, a kiln with a peripheral edge surface with a faceted shape will warrant a protective collar with a body portion having a given number of facets substantially corresponding in size, shape, and disposition to at least some of the facets of the peripheral edge of the kiln sidewall. For example, a kiln with eight facets will beget a protective collar having eight facets, a kiln with 10 facets will beget a protective collar with ten facets, and so on. Together, the kiln and the protective collar can be considered a combination yielding protection to the kiln not known to the prior art. 
     The body portion, which may or may not form a complete ring, can have a width approximately equal to the thickness of the peripheral edge surface of the kiln sidewall, an inner dimension between opposed inner edges approximately equal to an inner dimension between opposed inner edges of the peripheral edge surface, and an outer diameter between opposed outer edges approximately equal to an outer dimension between opposed outer edges of the peripheral edge surface. In certain embodiments, the body portion can have a width within thirty percent of the thickness of the peripheral edge surface of the kiln sidewall. 
     Means for preventing dislocation of the protective collar relative to the peripheral edge surface of the kiln sidewall when the protective collar is applied in alignment with the peripheral edge surface of the kiln sidewall can additionally be incorporated. That means can comprise a means for preventing sliding in a first direction over the upper peripheral edge surface when the protective collar is applied in alignment with the peripheral edge surface while permitting sliding in a second direction opposite the first direction off of the peripheral edge surface. In certain embodiments, the means can comprise at least one stop fixed to the body portion that has a portion that projects beyond the lower surface of the body portion. For example, there can be a plurality of stops spaced over less than a 180-degree span along the body portion of the protective collar. 
     To facilitate shipping and storage and potentially to avoid obstructions on the kiln, the stops could be pivotable from a first position where stops do not project beyond the lower surface of the body portion and a second position where the stops project beyond the lower surface of the body portion. In one such embodiment, the stops can be L-shaped with a first leg received into a borehole in the outer edge of the body portion and a second leg pivotable from a first position where the second leg does not project beyond the lower surface of the body portion and a second position where the second leg projects beyond the lower surface of the body portion. Still further, it is contemplated that means can be provided for permitting alternate positioning of the stops, such as by having alternate boreholes or fastening apertures to which the stops can be secured. 
     As disclosed herein, the protective collar can enable a method for protecting the peripheral edge surface of the kiln. One would provide a kiln with a peripheral kiln sidewall that has a peripheral edge surface of a given shape, size, and thickness, select a protective collar with a rigid body portion with an upper surface, a lower surface, an inner edge, an outer edge, and a shape and size approximately corresponding to the shape and size of at least a portion of the peripheral edge surface of the kiln sidewall, and apply the protective collar to the kiln with the lower surface of the body portion facing the peripheral edge surface of the kiln sidewall and with the shapes of the protective collar and the peripheral edge surface substantially aligned. With the protective collar so applied, a loading of articles relative to the kiln can be undertaken with minimized risk of damage to the fragile firebrick of the kiln sidewall. 
     One will appreciate that the foregoing discussion broadly outlines the more important goals and features of the invention to enable a better understanding of the detailed description that follows and to instill a better appreciation of the inventor&#39;s contribution to the art. Before any particular embodiment or aspect thereof is explained in detail, it must be made clear that the following details of construction and illustrations of inventive concepts are mere examples of the many possible manifestations of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings: 
         FIG. 1  is a perspective view of a top loading kiln according to the prior art; 
         FIG. 2  is a perspective view of the kiln of  FIG. 1  after a period of use; 
         FIG. 3  is a top plan view of another top loading kiln as disclosed by the prior art; 
         FIG. 4  is a top plan view of a further top loading kiln according to the prior art; 
         FIG. 5  is a top plan view of a protective collar for kilns according to the present invention; 
         FIG. 6  is a view in front elevation of the protective collar of  FIG. 5 ; 
         FIG. 7  is a view in side elevation of the protective collar of  FIG. 5 ; 
         FIG. 8  is a perspective view of a protective collar pursuant to the invention disclosed herein applied to a top loading kiln; 
         FIG. 9  is a perspective view of an alternative protective collar under the present invention; 
         FIG. 10  is a perspective view of a protective collar according to the present invention designed for use in relation to a round kiln; and 
         FIG. 11  is a view in front elevation of another protective collar under the present invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     As is the case with many inventions, the present invention for a protective collar for kilns is subject to a wide variety of embodiments. However, to ensure that one skilled in the art will be able to understand and, in appropriate cases, practice the present invention, certain preferred embodiments of the broader invention revealed herein are described below and shown in the accompanying drawing figures. Before any particular embodiment of the invention is explained in detail, it must be made clear that the following details of construction and illustrations of inventive concepts are mere examples of the many possible manifestations of the invention. 
     As noted above, the present inventor&#39;s basic object is to provide a protective collar for kilns that prevents wear and damage in relation to the upper surface of the kiln. An embodiment of such a protective collar is indicated generally at  50  in  FIGS. 5 through 7 . There, one can see that the protective collar  50  is founded on a body portion  52 . In the depicted embodiment, the body portion  52  forms a complete ring. The body portion  52  is substantially flat with what can be considered an upper flat surface and a lower flat surface. The body portion  52  has a width W, an inner dimension D I  measured as the distance between opposed inner edges, and an outer diameter D O  measured as the distance between opposed outer edges. 
     The body portion  52  can be formed from any suitable material or combination of materials. In certain contemplated embodiments, the body portion  52  can be crafted from wood, such as a panel of plywood or from multiple pieces of wood coupled in any suitable manner. Other potential materials include metal, temperature resistant polymeric material, or any suitable resinous or composite material. In any event, the body portion  52  is preferably sufficiently rigid to resist bending and able to withstand elevated temperatures. 
     The body portion  52  can have a shape and size corresponding to the shape and size of the upper peripheral edge surface  15  of the kiln  10  with which the protective collar  50  is to be used. Therefore, the octagonal protective collar  50  depicted in  FIGS. 5 through 7  would ideally be applied to a kiln  10  with an octagonal sidewall  12  as shown in  FIG. 3 . The protective collar  50  can have an inner dimension D I  between opposed inner edges approximately equal to or within a predetermined range of an inner dimension D I  between opposed inner wall surfaces of the kiln sidewall  12  and an outer dimension D O  between opposed outer edges approximately equal to or within a predetermined range of an outer dimension D O  between opposite outer wall surfaces of the kiln sidewall  12 , possibly including or not including insulation. With that, the width W of the protective collar  10  can be approximately to the thickness T of the sidewall  12 , potentially including or not including insulation and other materials. 
     So shaped and sized, the protective collar  50  can be applied to the kiln  10  during periods of loading, unloading, maintenance, and the like as shown in  FIG. 8  with the lower surface of the protective collar  50  resting atop and substantially overlying the upper peripheral edge surface  15  of the kiln sidewall  12 . The legs and corners of the protective collar  50  can be aligned with the legs and corners of the sidewall  12 . With that, a kiln operator can be provided with full access to the firing chamber  16  while the firebrick forming the upper peripheral edge surface  15  is protected against impact, chipping, and general wear. 
     Protective collars  50  according to the invention will thus ideally substantially mirror in shape and size the shape and size of the upper peripheral edge surface  15  of the sidewall  12  of the kiln  10  to which the collar  50  is to be applied. By way of example and not limitation, a pentagonal collar  50  will be provided for a pentagonal kiln  10 , a twelve-sided collar  50  will ideally be provided for a twelve-sided kiln  10 , an oval or round collar  10  as shown in  FIG. 10  will ideally be provided for an oval or round kiln  10  as shown in  FIG. 4 . The inner and outer dimensions D I  and D O  will approximately correspond such that the width W of the collar  50  will approximately match the thickness T of the kiln sidewall  12 . 
     It is preferred for the collar  50  to match the shape of each kiln  10  and to be within a given range of, such as within thirty percent (30%) greater or less than, the thickness T of the sidewall  12 . For example, a collar  50  for a kiln  10  with a 2 and ½ inch sidewall  12  might acceptably have a thickness T between 1.75 and 3.25 inches while a collar  50  for a kiln  10  with a 3 inch sidewall  12  might have a thickness T between 2.1 and 3.9 inches. 
     For a number of reasons, it may be preferable to form the protective collar  50  as a complete ring capable of entirely circumscribing the firing chamber  16 . For example, a complete ring may demonstrate greater rigidity and will be less likely to present an edge that might be harmful to the firebrick forming the sidewall  12  and the lid  14 . However, as one will appreciate with further reference to  FIG. 9 , it is within the scope of the invention for the body portion  52  of the protective collar  50  to be an incomplete ring with an open portion  0 , which could be a narrow slot or could span a substantial portion of the circumference of the body portion  52 . Preferably, though, the body portion  52  will span at least 120 degrees and more preferably 180 degrees or half of the circumference of the upper surface  15  of the sidewall  12  to permit adequate coverage and protection thereof. 
     The protective collar  50  could be applied with the goal of having its alignment and general position maintained by mere friction with repositioning carried out as necessary. However, embodiments are contemplated wherein means are provided for preventing sliding of the protective collar  50  relative to the upper peripheral surface  15  of the sidewall  12 . In certain embodiments, once the collar  50  is fully applied to the kiln  10 , the means can prevent relative sliding in a first direction while permitting relative sliding in a second, opposite direction. With that, the protective collar  50  can be applied to the upper peripheral edge surface  15 , and sliding in a first direction, such as away from the artisan, can be prevented while sliding in a second, opposite direction, such as toward the artisan and off of the upper peripheral edge surface  15 , can be permitted. After reading this disclosure and reviewing the accompanying drawings, a number of such means would likely occur to one skilled in the art. Except as it may be expressly limited, each such means is within the scope of the present invention. 
     One potential means for preventing relative sliding between the protective collar  50  and the upper peripheral edge surface  15  is shown in the embodiment of  FIGS. 5 through 8 . There, the means for preventing relative sliding comprises a plurality of stops  54  that have a portion thereof projecting beyond the flat bottom surface of the body portion  52 . More particularly, the stops  54  comprise L-shaped brackets with a first leg  51  fixed to the upper surface of the body portion  52  and a second leg  53  projecting downwardly below the lower surface of the body portion  52 . With that, the second legs  53  of the stops  54  can make contact with the outside edges of the sidewall  12  thereby to prevent sliding of the protective collar  50 . Where the stops  54  are disposed over less than 180 degrees around the body portion  52 , sliding of the body portion  52  onto the upper edge surface  15  of the sidewall  12  will be permitted until the stops  54  contact the sidewall  12 . At that point, sliding in a first direction, in this case further toward the lid  14 , is prevented while sliding in a second direction, in this case away from the lid  14  and off of the sidewall  12  to permit easy removal of the protective collar  50 , is permitted. 
     In the depicted embodiment, there are four stops  54  with one retained relative to each of four adjacent facets of the eight-facet protective collar  50 . With that, the stops  54  span over less than 180 degrees around the body portion  52 . The stops  54  can be retained in any suitable manner and could potentially be molded with or directly into the body portion  52 . In the depicted embodiment, the stops  54  are retained by fasteners  57  that are received through the stops  54  and into apertures  59  in the body portion  52 . 
     It is contemplated within the scope of the invention to provide a means for providing alternate positioning of the stops  54 , which could be advantageous where a given kiln  10  has an obstruction, such as a handle or the like (not shown), where a stop  54  might otherwise be located. In the present embodiment, the means for providing alternate positioning of the stops  54  comprises alternate fastening apertures  59 . Here, the body portion  52  has apertures  59  spaced over each of the four facets. More particularly, there are three sets of fastening apertures  59  for each facet to enable a selective positioning of the stops  54 . 
     An alternative stop arrangement is depicted in relation to the protective collar  50  of  FIG. 11 . In this embodiment, the stops  54  have L-shaped bodies with a first leg  51  for being received into a borehole  56  in the edge of the body portion  52  and a second leg  53  for selectively acting as a means for preventing relative sliding of the protective collar  50 . The first leg  51  of each stop  54  is threaded and is engaged with the threaded borehole  56 . The stops  54  are thus pivotably retained relative to the body portion  52  such that the stops  54  can be pivoted from a first position where the second leg  53  projects beyond the lower surface of the body portion  52  as in  FIG. 11  to a second position where the second leg  53  is generally parallel to the upper and lower surfaces of the body portion  52 . A possible alternative to the threaded stop  54  and threaded borehole  56  is contemplated wherein the stop  54  is a spring loaded swiveling device, similar to a bicycle kickstand arrangement. 
     Such a pivoting can facilitate shipping and storage. Furthermore, the stops  54  can be pivoted to a non-obtrusive position to permit the application of the protective collar  50  despite obstacles on the kiln  10  that might otherwise interfere with the application of the protective collar  50 . The embodiment of  FIG. 11  also includes means for providing alternate positioning of the stops  54  in the form of additional boreholes  56  spaced along the respective facets of the body portion  52  of the protective collar  50 . 
     In a typical method for using the protective collar  50  disclosed herein, an artisan will preferably first select a protective collar  50  that substantially matches the shape and size of the upper peripheral edge surface  15  of his or her kiln  10 . After opening the lid  14 , the artisan can then apply the protective collar  50  to the kiln  10  with the lower surface of the body portion  52  facing the upper peripheral surface  15  of the sidewall  12 . Where one or more stops  54  are provided, the artisan can position the protective collar  50  with the stops  54  contacting the outer surface of the sidewall  12 . If necessary, stops  54  can be relocated to avoid obstacles on the outer surface of the sidewall  12 . Where the kiln  10  is a shape other than round, the artisan can ensure that the orientation of the body portion  52  is aligned with the orientation of the sidewall  12 . Articles, such as ceramics and kiln furniture, can then be inserted into the firing chamber  16  with minimized risk of damage to the upper peripheral edge surface  15 . The protective collar  50  can then be removed, the lid  14  partially or entirely closed, and the kiln  10  heated to produce the desired heating effect. When the artisan determines one or more articles are to be removed, the lid  14  can be reopened, the protective collar  50  can be reapplied as described above, and the articles can be removed, again with minimized risk to the firebrick of the sidewall  12 . 
     As shown and described, the protective collar  50  for kilns  10  can enable a user to prevent wear and damage in relation to the upper edge surface  15  of the kiln  10 . With that, the protective collar  10  can increase the useful life of the kiln  10  and reduce the need for repairs thereto. By preserving the upper peripheral edge surface  15 , the protective collar  50  enables a tight seal between the lid  14  and the upper edge surface  15  to be maintained thereby improving energy efficiency and firing quality while preventing the deleterious effects of escaping gasses. Even further, when the protective collar  50  is shaped and sized within an acceptable range of the shape and size of the upper peripheral edge surface  15 , full or substantially full dimensional access to the firing chamber  16  will be permitted for loading and unloading even as the collar  50  protects the fragile firebrick at the upper edge surface  15  of the kiln  10 . Still further, with the firebrick protected, the user need not be quite as cautious in leaning over the kiln to load and unload objects thereby improving comfort and ease while saving precious time in loading and unloading articles relative to the kiln  10 . 
     With certain details of the present invention for a protective collar  50  for kilns  10  disclosed, it will be appreciated by one skilled in the art that changes and additions could be made thereto without deviating from the spirit or scope of the invention. This is particularly true when one bears in mind that the presently preferred embodiments merely exemplify the broader invention revealed herein. Accordingly, it will be clear that those with certain major features of the invention in mind could craft embodiments that incorporate those major features while not incorporating all of the features included in the preferred embodiments. 
     Therefore, the following claims are intended to define the scope of protection to be afforded to the inventor. Those claims shall be deemed to include equivalent constructions insofar as they do not depart from the spirit and scope of the invention. It must be further noted that a plurality of the following claims express certain elements as means for performing a specific function, at times without the recital of structure or material. As the law demands, these claims shall be construed to cover not only the corresponding structure and material expressly described in this specification but also all equivalents thereof that might be now known or hereafter discovered.