US20160040889A1

US20160040889A1 - Hearth panel apparatus for fireplace

Info

Publication number: US20160040889A1
Application number: US14/818,900
Authority: US
Inventors: Michael T. Rogers
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-08-08
Filing date: 2015-08-05
Publication date: 2016-02-11

Abstract

A hearth panel includes an edge member defining a geometric shape, such as a continuous loop, and two (or more) non-combustible panels with perimeters contained inside the edge member, and with the panels defining an air gap therebetween, thus providing an R value of over 2.0 and as high as 3.5 or more. Spacers in the air gap help prevent drooping of the panels. Tile is attached to the top panel for aesthetics. In some versions, the edge member includes a flange forming the gap's thickness. In some versions, the edge member is roll formed from constant thickness sheet, or extruded from an extrudable material such as aluminum.

Description

This application claims benefit under 35 USC section 119(e) of provisional application Ser. No. 62/035,026, filed Aug. 8, 2014, entitled HEARTHPAD, the entire contents of which are incorporated herein in their entirety.

BACKGROUND OF THE INVENTION

The present invention relates to hearth panels such as are located under, behind, and/or in front of fireplaces and heaters, and more particularly relates to a hearth panel apparatus having novel cost-competitive construction and high insulating R value.
Hearth panels have been manufactured for the fireplace industry since the late 1970's. They are used to protect combustible surfaces in homes having a wood stove, pellet stove, gas stove, and/or other fireplace structure (collectively referred to herein as “heaters”), where the hearth panels provide a non-combustible surface for the heater to sit on. Each brand and style of heater has specific requirements as to the level of floor protection and clearances to combustible surfaces, including both floors and walls near the heater/stove installation.
The hearth panel protects combustible surfaces from both radiant heat and possible sparks and embers that potentially could be released when the door of the heater is opened, or possibly if the glass in the door is compromised. Certified labs have established standards for hearth pads to determine the level of protection they provide. Tests include the R value of the hearth panel, impact tests, heat degradation tests and burning ember tests, as well as other tests.
In 2007, the industry divided hearth panels into type 1 and type 2 categories. The type 1 hearth panel is required to provide spark and ember protection. The type 2 hearth panel is required to provide spark and ember protection, and must also provide thermal protection. The higher the R value, the greater the protection for combustible surfaces such as carpet and wood floors. Today's market contains very efficient stoves with larger radiant heat output than in the past. This resulted in demand for greater radiant heat protection for hearth panels. Today, hearth panels must provide R values in excess of 2.5 if they are to protect all radiant stoves currently in the marketplace. Hearth panel manufacturers have not succeeded in designing and producing a single hearth panel that singularly satisfies all wood stove models hearth protection requirements. As a result, manufacturers of hearth panels must carry a variety of different hearth panel types in their inventory, which leads to increased manufacturing cost, inventory-in-process costs, and other costs associated with producing a wide variety of different products at lower volumes.
It is a requirement that all wood burning stoves include in their owner's manual a section addressing installation and all necessary floor and wall protection requirements. The owner of a newly purchased stove or professional installer must consult the manual to determine adequate floor protection and in some cases wall protection needed to insure a safe installation.
Presently, there are no hearth panels approved for R values that accommodate all of these higher requirements. For example, several known hearth panels have R values of only 1.40 to 1.60, which is well below an R value of 2.5. Yet there are at least 15 models of wood burning stoves sold today with R value requirements that exceed 1.60.
To provide extra protection, some hearth panel manufacturers add secondary products such as elevated platforms referred to as pedestals that include additional layers of non-combustible substrates. This adds additional protection increasing the R values to satisfy the installation requirement of the specific heater. However, adding a second product with another product to achieve satisfactory and acceptable protection has inherent problems. For example, it introduces opportunities for confusion by consumers, and misinformation from sales personnel, about what products must be combined to provide a safe wood stove installation. Some consumers purchase a wood burning stove from one source and a floor protector from a second source. This often results in an error where inadequate hearth panel protection is matched with the wood stove heater. Any of these conditions can potentially cause a fire in the consumer's home.
There are variations of type 2 hearth panel designs on the market. Numerous manufacturers of hearth pads have tested and approved designs. But none have accomplished a design that by itself protects combustible surfaces from all stoves offered on the market.
One hearth panel design has incorporated a steel angle iron (see FIG. 1) or aluminum edge (see FIG. 2) that supports a substrate. Tile, stone, granite or marble are added to the substrate surface for esthetics. There remains under the substrate an airspace that extends from the substrate to the existing combustible floor of the home. Aluminum supports are added to the substrate to prevent sagging. This manufacturer obtains his elevation height for attaching his substrate by using an angle iron style frame, adding narrow strips of the substrate and attaching that to the inside of the angle iron. Once the level is established, the substrate is attached to the buildup. This hearth panel design has no sealed internal airspace. The hearth panel relies on the substrate and the airspace under the substrate to achieve its thermal protection. This hearth panel design has been in use since before 2007. This design has no internal airspace. This design provides a 1.6 R value. (See FIG. 1.)
Another hearth panel design starts with an aluminum extruded edge that has a horizontal flange approximately half way up the inside of the frame. A non-combustible substrate is attached to the frame. A second noncombustible substrate is attached to the bottom of the first layer. The bottom layer is smaller in width and length than the top layer and actually is positioned 3-4 inches away from the panel's edge along its entire perimeter. The manufacturer refers on his web site to this design as follows: ½″ mineral fiber board installed to within inches of the frame. They go on to say “does not rely on air pocket for thermal value”. The combination of the two substrates achieves an R value of 1.6. This design has been manufactured since 2008. (See FIG. 3.)
Another hearth panel design starts with an angle iron frame. The bottom has a particle board attached to the frame. Then a noncombustible substrate is attached to the top of the particle board. The esthetic surface material is attached by thin set to the noncombustible substrate. The design has been used since 2009. This design provides a 1.4 R value. (See FIG. 4).
There does not exist a universal solution for obtaining adequate R values necessary for the newer high output radiant wood stoves using only one single hearth panel product. None offered for sale on the market today exceed an R value of 1.6. This leaves several wood burning radiant stoves without a single complete-as-sold hearth panel product that provides the safety needed for installations. Instead, a second product must be used in conjunction with the hearth panel to satisfy the required protection.
Besides the issue of inadequate R values, a second issue exists. All known manufactures use their edging material shapes to provide for a 90 degree vertical edge. Esthetic materials (tiles etc.) are attached to the panel surface and closely approach the outside vertical edge of the hearth panel. The ensuing gap that occurs between the edge and the tile is filled with grout. In many cases the tile or stone is installed very close to the panel edge leaving insufficient gaps to properly pack the void with grout. (See FIG. 3.)
This spacing gap produces a weakness in the product. Failures often occur due to the following actions. Hearth panels are shipped to customers on pallets where fork lifts can damage this gap, installers can drop the hearth panel on its edge during transportation, and the home owner can damage this gap during regular use. Furthermore, the grouted area as described above has a gap that can be compromised by the flex in the panel with the weight of the wood stove and with people stepping onto its edge. The result of these circumstances is hearth panels with grout falling out of the gap.
Some known hearth panels are designed to provide airspace under the hearth panel (i.e. between the hearth panel and the building floor). However, when these are installed on carpet, the airspace is reduced since the carpet tends to intrude into the airspace as it partially collapses under the weight of the wood stove or heater. Notably, wood stoves and heaters often exceed 100 pounds. Further, testing of such hearth panel designs suggests they only provide R values of about 1.6, which is considerably less than the R value desired by many (if not most) wood stoves and heaters.
An improvement is desired that provides savings/improvements in terms of material and assembly cost, capital investment, efficiency of install, and safety. Also, a universally-usable product is desired having an R value sufficient high for use in all heaters, such as an R value of over 2.0 and more preferably in excess of 2.50.

SUMMARY OF THE PRESENT INVENTION

In one aspect of the present invention, a hearth panel includes an edge member defining a geometric shape; at least two non-combustible panels with perimeters contained inside the edge member and that define an air gap therebetween; and spacers in the air gap preventing drooping of a top one of the non-combustible panels.
In a narrower aspect of the present invention, the edge member includes a flange that spaces at least two non-combustible panels apart, the flange having a thickness equal to the spacers.
In a narrower aspect of the present invention, the hearth panel includes tile or stone on the top one of the non-combustible panels.
In another aspect of the present invention, a hearth panel includes an edge member having a cross section with a vertical flange and a horizontal flange and connected to but spaced from the vertical flange by a connecting flange; two non-combustible panels inboard of the vertical flange and located on or under the horizontal flange and defining an air gap therebetween; and spacers in the air gap preventing drooping of a top one of the panels.
In another aspect of the present invention, a hearth panel includes an edge member formed from a sheet having a constant width and constant thickness. The edge member has a cross section including a vertical flange and a horizontal flange. At least one non-combustible panel includes a perimeter bounded by the vertical flange.
In another aspect of the present invention, an edge apparatus for a hearth panel is provided. The edge comprises a profile having a cross section including a first edge portion that extends upwardly, a first intermediate portion that extends outwardly and downwardly from a bottom of the first edge portion, a center portion that extends horizontally inwardly from a bottom of the first intermediate portion, a second intermediate portion that extends vertically upwardly from an inner edge of the center portion, and a second edge portion that extends horizontally inwardly from an upper edge of the second intermediate portion.
In a narrower form, the intermediate portion or the second edge portion have two or more ribs increasing the air gap thickness defined by the cross section and by an insulative panel attached to and supported by the profile.
In another aspect of the present invention, an edge for a hearth panel includes an edge member formed from a sheet having a constant-thickness and having a cross section including a first edge portion that extends upwardly, a center portion that extends horizontally inwardly, and a second edge portion that extends horizontally inwardly and that is spaced from the first edge portion. The edge member has a length lying in a single plane and includes at least four linear sections each joined by a sharp corner. Each sharp corner is formed by one of bending and welding, where the corner formed by bending includes forming a notch at the corner so that when bent the length stays in the single plane, and where the corner formed by welding includes cutting an angle on abutting ends so that when welded the length maintains the cross section to and around the welded corner.
In another aspect of the present invention, an edge for a hearth panel is provided, where the edge comprises an edge member formed from a sheet having a constant-thickness and having a cross section including a first edge portion that extends upwardly, a center portion that extends horizontally inwardly, and a second edge portion that extends horizontally inwardly and that is spaced from the first edge portion. The edge member has a length lying in a single plane and includes at least four linear sections each joined by a sharp corner, each sharp corner is formed by a corner bracket connecting adjacent ends of adjacent ones of the at least four linear sections.
These and other aspects, objects, and features of the present invention will be understood and appreciated by those skilled in the art upon studying the following specification, claims, and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-4 are side views of existing prior art hearth panel designs, with FIG. 1A showing a front perspective view of one shape of such designs.

FIGS. 5, 6, 6A, and 7 are side views of innovative hearth panels, FIG. 5 showing a roll formed edge member and two (or more) MgO non-combustible panels spaced apart by an air gap, FIGS. 6-6A showing an edge member (roll formed or extruded) having a right-angle shape and two (or more) non-combustible panels spaced apart by an air gap, and FIG. 7 showing a extruded edge member with two (or more) non-combustible panels spaced apart by an air gap.

FIGS. 8-9-9A are cross sectional views of modified roll formed edge members for innovative hearth panels.

FIGS. 10-11 are cross sectional views using the modified roll formed edge members of FIG. 9, with the FIGS. 10-11 being similar construction, but FIG. 11 showing use of a higher R value non-combustible substrate.

FIG. 12 is a cross sectional view using the modified roll formed edge members of FIG. 9, but using only a single non-combustible core layer in combination with hat channels steel supports supporting the core layer above a floor space. Other spacer profiles may be chosen.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

The present innovation (referred to herein as “new design” or “ND”) is a hearth panel that incorporates a unique shape and construction to the edge which addresses the gaps issue described above.
The illustrated hearth panel 30 (FIG. 5) includes an edge member 31 (roll formed, extruded, or otherwise formed), two (or more) non-combustible panels 32 and 33 with an air gap 34 therebetween, and tile 34 (e.g. slate, marble, sandstone, granite, or the like) attached to a top of the panels 33 using grout or thinset or other adhering material. Spacers 35 are placed in the air gap 34 inboard of the edge member 31, with the spacers 35 having a thickness equal to the inboard flange of the edge member 31. The spacers 35 prevent drooping of a top of the panels 33, so that the air gap is consistently maintained and thus the R value maintained. The edge member 31 includes portions 40-44 formed from a sheet having a constant-thickness and having a constant cross section. The constant profile includes a first edge portion 40 that extends upwardly, a first intermediate portion 41 that extends outwardly and downwardly from a bottom of the first edge portion 40, a center portion 42 that extends horizontally inwardly from a bottom of the first intermediate portion 41, a second intermediate portion 43 that extends vertically upwardly from an inner edge of the center portion 42, and a second edge portion 44 that extends horizontally inwardly from an upper edge of the second intermediate portion 43. The first and second edge portions 40 and 44 form an angle that is slightly greater than 90 degrees, thus better allowing for grout as discussed below. The first intermediate portion 41 is non-planar for aesthetics. The second intermediate portion 43 is sufficient in length so that the bottom non-combustible panel 32 fits under the second edge portion 44 and flat on a floor surface. Notably, the air gap can be any dimension desired, such as ⅛″ to ¼″ or more.
The versions shown in FIGS. 5-7 include similar components, features and characteristics. The same components, features and characteristics are identified using the same numbers and/or using the same numbers but with letters or symbols (such as “A”, “B”, and/or using an apostrophe-') to simplify the disclosure and reduce redundant discussion.
The ND (new design) discussion begins with the edge member (also called an “edge” herein). Its shape is unique, and further the edge member can be roll formed in a manner providing considerable savings in part cost, material cost, and providing high quality construction. Regarding the edge member, instead of a straight vertical surface, the edge tilts outwards creating additional gap spacing. This additional gap spacing allows for more grout to be applied into that space. This design strengthens that portion of the hearth panel, reducing grout loss. (See FIG. 5.) As the edge descends further downward, the profile pattern introduces another feature that allows the side of the top layer of the MgO to come into contact with the edge. This contact prevents thin set and grout from falling down into the lower section of the profile. If this was not designed into the shape, then hardened grout and thin set could fall into that space, cure and harden, and rattle around.
Additionally, this profile feature provides for 2 right angle attachment sites. These sites create an improved and more secure attachment. The edge's descending profile comes into contact with the floor, returns to the interior of the product, providing adequate support before ascending upwards ½ inch. At ½″ the shape makes a 90 degree bend and travels inward. This produces a flange parallel to the floor resulting in opposing right angles. (See FIG. 5.) Into each right angle of the edge, a ½″ sheet of MgO panel is attached. In some cases, the lower substrate may be a Micore 300, primarily used in place of the MgO product when weight becomes a consideration. This creates a unique design whereas the product can accommodate 2 sheets of non-combustible substrates now separated by the flange creating a sealed internal airspace.
The present design allows for a variation on the composition of the core layers. In addition to two layers of MgO ½″ substrates, a second option is to substitute the bottom layer of MgO substrate with a layer of Micore 300. It would also reduce the weight of the product.
In the illustrated design, three significant aspects thus create a much higher R value. It is noted that tile and thin set do not add very much R value. The illustrated hearth panel includes two layers of MgO panels (or Micore 300) and a single internal airspace formed between the two sheets. Alternatively, a single layer of MgO substrate can be used in combination with a bottom layer of Micore 300. Notably, the bottom of the hearth panel sits fully flush to the floor. This concept is new and, to my knowledge, has never been sold in the marketplace. The projected R value of the illustrated hearth panel is in excess of 2.0. Persons skilled in this art will understand that tested R values may vary from projected R values.
Thus, the ND creates unique features not used before in hearth pad designs. The ND solves the gap problem that has occurred at a top of many existing hearth panels. The ND creates opposing right angles by which a duo layer of substrate can be installed securely to the edge while making full contact with that edge. Also, it provides for an internal airspace layer. The internal airspace offers an R value of 0.50 or more by itself, plus the air has no cost or weight, such that it is believed to be an important and strategic aspect of this innovation.
To summarize, the illustrated edge (see for example FIGS. 5-12) includes the following advantages:

1. Vertical edge with outward bending profile allows for additional grouting.
2. Vertical edge with unique profile provides interior opposing right angles for MgO, micore 300 and other substrates attachments while maintaining exterior stylish profile.
3. Internal horizontal flange creates secure attachment sites for the substrates while providing an inherent internal airspace. The width of the flange determines the thickness of the airspace. This airspace will be ⅛″ or greater. A non-combustible spacer will be placed in the center of the gap to prevent any sagging across the airspace.
4. The internal flange may be notched to allow for bending and shaping at exacting locations.
5. ND allows for internal welds connecting ends without disturbing outside profiles.
6. Flanges can be pre-drilled to allow screws to assist the adhesive in attachment of the substrates to the right angles created by the profile shape.
7. The multiple bends and changing profiles of the edge add to the strength of the form.
8. The MgO product produces no off gassing.
9. The MgO product combusts at temperature in excess of 3000 F.
10. The MgO product carries Warnock Hersey stamp of quality.
11. The MgO product is referred to by its trademark at MagBoard. Over time other brands of MgO substrate may be used.
12. The vertical edge with unique profile provides improved strength due to the bends, while maintaining minimal wall thickness in the extrusion, yet also allows control of air gap thickness, while again allowing minimized wall thickness (e.g. FIG. 12).

Discussion of assembly: Steel coil is supplied to a roll form mill for production. The mill shapes the steel into a length necessary for each hearth panel shape and size. During the process of shaping the coil, the mill introduces pre-drilled holes as attachment sites for the substrates. Notches are placed in the vertical flange to facilitate accurate and sharp bending specific corner locations to form the desired shape.
The newly formed steel edge is placed in a fixture and bent using a mandrel bender that prevents deformation of the profile and that achieves accurate and precise shaping. Once the shape has been bent, the ends are welded on the inside of the frame so as to not disturb the aesthetic profile. Each of the two layers of ½″ MgO panel are installed onto the frame with adhesives and screws. A non-combustible spacer is centered between the two layers to prevent sagging and to support the integrity of the internal air space. The edge and due corer panel is ready for tile/stone/marble or granite to be attached to the top layer of the MgO substrate.
It is contemplated that variations could be made to the illustrated ND and still be within a scope of the present innovation. For example, there could be variations used to provide an internal airspace in a hearth panel besides the edge used in this particular ND design. A scope of the present innovation is believed to include any use of an internal air space with a hearth panel, regardless of a particular technique or particular construction used.
FIG. 6 illustrates a hearth panel 30A having an angle iron style edge, which edge could be extruded, roll formed, or bent on break die tooling. The edge is shaped to receive and for attachment of substrates. A planar panel non-combustible substrate is installed to a bottom of the angle shape. Then spacers are introduced which are positioned along the perimeter, sitting on top of the bottom layer but along the perimeter in order to provide for a second substrate installation. Then, a second layer of non-combustible substrate is attached to those spacers. This provides an internal airspace. Tile or stone (or etc.) is then set on the top layer of non-combustible substrate.
Notably, the edge can be extruded aluminum shapes, roll formed shapes, and/or shapes formed by other means. Design tooling could create wood products or plastic products that could establish a support flange on the interior similar to FIG. 3 or 5. Then, using the support flange, two non-combustible surfaces could be attached to the outside edge resulting in an interior enclosed airspace.
It is contemplated that a hearth panel using the present technology can incorporate additional layers of non-combustible sheet and spacers to form a second and possibly a third internally-enclosed airspace, thus achieving even higher R values. Alternatively, thinner layers of substrate can be attached to the internal flange, producing an airspace between the existing floor and the hearth panel as well as the sealed internal airspace.
FIGS. 6-6A illustrate hearth panels 30A and 30A′ incorporating an edge that is extruded, roll formed, stock angle iron, wood, or plastic product shaped in an angle or channel form. The bottom substrate is attached to the edge. Spacers are placed around the perimeter sitting on top of the bottom layer. Then, a second substrate is attached to the layers. This creates an enclosed airspace, which is unlike previous hearth pads that used a C-channel or angle iron or other shape in the edge member. Tile is attached to the top layer. This pattern could be repeated various times to accomplish multiple sealed enclosed internal airspaces.
FIG. 7 illustrates a hearth panel 30B with an edge that is extruded, roll formed or shaped plastic or wood. The edge creates an internal flange. A substrate of lesser thickness is attached to the underside of the flange, leaving an airspace below the substrate. A second substrate is attached on top of the flange. This creates a second airspace. Tile is attached to the top layer of the substrate.
It is contemplated that hearth panel's edge member can be formed from a sheet having a constant-thickness and having a cross section including a first edge portion that extends upwardly, a center portion that extends horizontally inwardly, and a second edge portion that extends horizontally inwardly and that is spaced from the first edge portion. The edge member has a length lying in a single plane and includes multiple linear sections each joined by a sharp corner. Notably, the edge member can form a continuous uninterrupted loop, such as a five or six-sided loop often found in hearth panel shapes. Also, it is contemplated that the edge member can leave off a rear linear section, such that it defines an open section (rather than a continuous loop).
It is contemplated that the hearth panel's edge member will have multiple linear sections joined by sharp corners. The term “sharp corners” is used herein to mean that adjacent linear sections are joined by a portion of material that has minimal or zero radius. It is significant that the sharp corner be formed so that the entire edge member continues to lie in the single horizontal plane of its use position. It is contemplated that the sharp corner can be formed by various means. For example, the sharp corners can formed by one of bending and welding. Where the corner is formed by bending, the length is notched at the corner so that when bent, the length stays in the single plane (i.e. so that the material does not bulge upwardly or downwardly when the sharp corner is bent). Where the corner formed by welding, ends of the linear sections are cut at an angle on their abutting ends so that, when welded, the welded length maintains the cross section to and around the welded corner. The angle cuts are used to eliminate the need to overlap flanges at the sharp corners.
Also, instead of welding or bending, it is contemplated that the sharp corners can be formed by using a corner bracket that both joined adjacent abutting ends of linear sections and also that forms a sharp, aesthetic corner. The corner bracket would include short legs matching a profile of the linear sections and attached to adjacent ends of the linear sections, and a non-radiused section (or sharply radiused section) joining the short legs. Also, it is contemplated that a combination of bending and/or welding and/or brackets can be used.
It is noted that surface materials (previously referred to as “tiles”) are placed on top of the hearth apparatus, such as slate, marble, sandstone, granite, and other materials having an aesthetic appearance and suitable non-flammable characteristics. They can be various shapes and sizes (i.e. various thickness and horizontal dimensions) and held in place by various means, such as grout or cement.
FIG. 8 discloses a modified roll formed edge member 31 C for a hearth panel. The edge member 31 C is modified to utilize steel having a thickness that is reduced up to 0.06 inches from the edge members shown in FIGS. 5-7, such as to a thickness of about 0.06 inches (i.e. 1/16 inch thickness). The edge member 31C includes portions 40C-44C, and additionally includes a doubled-back portion 44C′ that maintains a gap thickness of ⅛ inch in the airspace. It is contemplated that a length of the doubled-back portion 44C′ can be as long or as short as a particular design or application requires. FIG. 8 shows another modified edge member 30D with portions 40D-44D. Edge member 30D also uses 0.06 inch thick steel material, but instead of a doubled-back portion, the flange 44D includes two (or more) ridges 44D″ so that a total defined thickness (i.e. a distance from a tip of the upward channels to a bottom surface of the flange 44D) is ⅛ inch thick. Thus, this flange 44D maintains the air gap thickness of ⅛ inch (0.06 inch). It is noted that various preferred dimensions of linear and radiused portions are included in FIGS. 8-9, but a scope of the present invention is considered to include many variations as may be required for particular applications.
It is contemplated that the thinner steel of FIGS. 8-9 provides adequate strength. Also, see the extruded edge of FIG. 9A with spacer ribs 44D″, and compare to the extruded edges of FIGS. 5 and 7 which can also use similar spacer ribs. The ribbed shape of edge 31D (FIG. 9) or folded-back shape of edge 31C (FIG. 8) or ribbed extruded shape of edge 31D′ with spacer ribs 44D″ (FIG. 9A, compare to FIGS. 5 and 7) maintains the ⅛″ (or more) internal air gap. The illustrated edge members provide for lower steel cost, lower tool cost, and lower part cost over the thicker parts of 0.1 inch thickness or thicker. Cut off dies cut the 45 degree and 22-½ degree cut off necessary to accomplish the proper abutting surfaces/shapes for welding corners so that the edge members combine to form a continuous loop or a partial loop in a hearth panel arrangement. The roll form tooling and the cut off dies constitute a two part procedure to form the edge shapes and lengths needed for welding parts together in the desired hearth shapes.
FIGS. 10-11 are cross sectional views using the modified edge members (roll formed or extruded) of FIG. 9, with the FIGS. 10-11 being similar construction, but FIG. 11 showing use of a higher R value at the lower non-combustible substrate. Data on FIGS. 10-11 also provides details of the R values and dimension of the air space.
It is contemplated that the present edge member can be used in other ways. For example, FIG. 12 is a cross sectional view using the modified edge member of FIG. 9, but using only a single non-combustible core layer in combination with hat channels steel supports or other style supports supporting the core layer above a floor space. Data on FIG. 12 also provides details of the R values and dimension of the air space.
It is noted that the edge member of FIG. 9 not only reduces material cost, but also allows easier roll forming or extruding, thus leading to less expensive tooling, yet the double ribbed form on the horizontal flange provides for the ⅛ inch air space and can be increased to achieve higher R-values.
It is contemplated that the present innovative edge members (also call “profiles” herein) can be formed in ways other than roll forming. For example, a variant of the original edge member is made by extruding processes while still utilizing the majority of the shape and concepts previously described. For example, an edge member like that shown in FIGS. 5-11 has been extruded from aluminum in given lengths that are conducive to cutting out parts for the hearth pad. The extrusion was about 0.06 inches in thickness with two ribs located on the interior horizontal flange, the two ribs defining an air gap when insulative panels are supported by the extruded profile. It is conceivable that other thickness of edge member materials could be used. It is also conceivable that more than two ribs could be formed into the flange and a thickness greater than ⅛″ could be implemented. Current testing for R-values produced a R-value of 2.0 utilizing the ⅛″ airspace, 1 layer of ½″ MgO substrate and ½″ of micore 300 installed into the edge member. By adding reflective foil like materials and with slight increases of the airspace higher R-values can be achieved. This patent would include other insulative materials added to the airspace to increase R-values.
To form a hearth pad, the extruded aluminum edge member is placed in a chop saw line to be cut into desired lengths, and those lengths are placed into welding jigs to fix the pieces of aluminum in exact hearth configurations. Then the clamped pieces are welded internally to provide a final shape and to preserve the outside profile and good corner appearances. Any residue from the chop saw is sanded from the aluminum corners, the edge member is then painted and ready for attachment of the substrates.
The ribbed attachment flange allows the use of ultra-thin aluminum extrusions while obtaining different airspace gaps for increasing R-values by simply increasing the size of the ribs on tools used to extrude the aluminum shape. The numerous shape changes in the profile of the edge member greatly increase the strength of the edge member. This allows for the use of ultra-thin aluminum edge members that both greatly reduce the weight of the hearth pad, decreases the overall cost of the hearth pad yet provides for a structurally sound, esthetically pleasing and versatile hearth pad. Also, different rib sizes allow the designer to control a size of the air gap space and hence provide desired thermal properties in the apparatus simply by changing a shape/configuration of the flange.
It is contemplated that the edge member could be produced from plastic, steel, aluminum and other materials (including even the use of wood) to achieve the same result. Over time substrates other than micore 300 and Magnesium Oxide panels may implemented in this hearth pad configuration that will add positive features to this design.
Thus, it is to be understood that variations and modifications can be made on the aforementioned structure without departing from the concepts of the present invention, and further it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise.

Claims

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

1. A hearth panel comprising:

an edge member defining a geometric shape;

at least two non-combustible panels with perimeters contained inside the edge member and that define an air gap therebetween; and

spacers in the air gap preventing drooping of a top one of the non-combustible panels.

2. The hearth panel of claim 1, wherein the edge member includes a flange that spaces the at least two non-combustible panels apart, the flange having a thickness equal to the spacers.

3. The hearth panel of claim 2, wherein edge member has an exterior surface that is non-planar and aesthetically shaped.

4. The hearth panel of claim 1, including one of tile or stone on the top one of the non-combustible panels.

5. The hearth panel of claim 1, wherein the geometric shape defines a continuous loop lying in a horizontal plane when in a use position.

6. The hearth panel of claim 1, including an additional non-combustible panel forming an additional air gap with the first-mentioned non-combustible panels.

7. A hearth panel comprising:

an edge member having a cross section with a vertical flange and a horizontal flange;

two non-combustible panels inboard of the vertical flange and located on or under the horizontal flange and defining an air gap therebetween; and

spacers in the air gap preventing drooping of a top one of the panels.

8. A hearth panel comprising:

an edge member formed from a sheet having a constant width, the edge member having a cross section including a vertical flange and a horizontal flange connected to but spaced from the vertical flange by a connecting flange; and

at least one non-combustible panel with a perimeter bounded by the vertical flange.

9. The hearth panel of claim 8, wherein the horizontal flange is notched at corners to facilitate forming the corners while preventing deformation when forming the corners.

10. An edge apparatus for a hearth panel, the edge comprising:

a profile formed from a sheet having a cross section including a first edge portion that extends upwardly, a first intermediate portion that extends outwardly and downwardly from a bottom of the first edge portion, a center portion that extends horizontally inwardly from a bottom of the first intermediate portion, a second intermediate portion that extends vertically upwardly from an inner edge of the center portion, and a second edge portion that extends horizontally inwardly from an upper edge of the second intermediate portion.

11. The edge apparatus defined in claim 10, wherein the first intermediate portion extends outwardly and downwardly at an angle.

12. The edge apparatus defined in claim 10, wherein the first and second edge portions do not touch each other but form an angle that is 90 to 95 degrees.

13. The edge defined in claim 10, wherein at least one of the intermediate portion and second edge portion have two or more ribs increasing an air gap defined by the cross section and by an insultative panel attached to and supported by the profile.

14. An edge for a hearth panel, the edge comprising:

an edge member formed from a sheet having a constant-thickness and having a cross section including a first edge portion that extends upwardly, a center portion that extends horizontally inwardly, and a second edge portion that extends horizontally inwardly and that is spaced from the first edge portion;

the edge member having a length lying in a single plane and including at least four linear sections each joined by a sharp corner, each sharp corner being formed by one of bending and welding, where the corner formed by bending includes forming a notch at the corner so that when bent the length stays in the single plane, and where the corner formed by welding includes cutting an angle on abutting ends so that when welded the length maintains the cross section to and around the welded corner.

15. An edge for a hearth panel, the edge comprising:

the edge member having a length lying in a single plane and including at least four linear sections each joined by a sharp corner, each sharp corner is formed by a corner bracket connecting adjacent ends of adjacent ones of the at least four linear sections.