Abstract:
A refrigeration wall system including interlocking panels having fastening mechanisms coated with a backing material, and a method for making the fastening mechanisms. The fastening mechanisms are embedded within insulating material inside of the interlocking panels. The backing material improves the adherence of the fastening mechanisms to the insulating material and thereby increases the overall strength of the refrigerator wall system.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a refrigeration wall system composed of interlocking panels. More specifically, the present invention relates to a refrigeration wall system having panel fasteners that are coated with a backing material that enhances the adherence of the fasteners to the panel&#39;s foam insulation. 
     BACKGROUND OF THE INVENTION 
     Certain types of walls, such as refrigerator walls, are assembled from insulated slab panels, which are factory molded from insulating materials such as urethane. Mounted within these panels are fastening housings for holding adjacent slabs in abutting positions as they are assembled. The fastening housings contain opposed locking devices. Usually the housings are mounted along the panel edges during the factory molding process, and thus the housings must adhere to the molding material in order to provide a secure interlocking of the panels. 
     One obstacle in the manufacture of refrigeration wall systems has been poor adherence of the metal fastener housings to typical insulating material such as urethane foam. In the past, this problem has been addressed by spraying the fastener housings with an adhesive before beginning the molding process in order to enhance the adherence of the fastener in the foam insulating material. This method did increase the pull strength of the foamed-in-place fastener, but proved to be labor intensive and costly. An alternative method was to apply the adhesive during the manufacture of the fasteners, but the adhesive tended to obstruct the equipment used to assemble the fasteners. Therefore, there continues to be a need for a fastener that will strongly adhere to the insulating foam in a refrigerator wall system while being easily produced and attached to the panels. 
     BRIEF SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a refrigerator wall system having panel fastening mechanisms with increased adherence to panel insulation, resulting in improved pull-strength and overall stability of the wall system. 
     It is a further object of this invention to provide a cost effective fastening mechanism for use in the refrigerator wall system that will not interfere with other processing equipment. 
     It is still another object of this invention to provide a method for making the fastening mechanisms for use in the refrigerator wall system. 
     To achieve these objectives, the present invention provides a refrigerator wall system having panel fastening mechanisms that are coated with a backing material. The backing material more strongly adheres to the insulating material than does the bare substrate of the fastener housing, and thus the backing material enhances the strength of the interlocking panels that constitute the refrigerator walls. 
     In one aspect of the invention, the backing material is a polymer. In another aspect of the invention, the backing material is a polyester. 
     In the method of the present invention, a backing material is added to a substrate material before the substrate is stamped to form the parts needed to assemble the fastening housings. The substrate is preferably a metal, and most preferably bare cold rolled steel, temper #4 with hardness range of B45 to B65. The backing material chosen must have a stronger adherence to insulating material than the substrate itself has to the insulating material. Suitable backers are polymers, such as polyesters, and/or epoxy resins. 
     The invention will be more clearly understood from the following description of the specific embodiment of the invention, together with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 is a perspective view of the front of the refrigerator of the present invention. 
     FIG. 2 is a rear exploded view showing the individual panels of the refrigerator of FIG.  1 . 
     FIG. 3 is an exploded view showing the relation of the corner panels of the refrigerator with the fastening mechanisms of the present invention. 
     FIG. 4 is an exploded view showing the relation of the ceiling panels with the fastening mechanisms of the present invention. 
     FIG. 5 is a top cross-sectional view of the male and female members of the fastening mechanism embedded in the insulating material of the refrigerator panels. 
     FIG. 6 is a lateral cross-sectional view of the fastening mechanism of FIG. 5 embedded in the insulating material of the refrigerator panels. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the accompanying drawings and initially to FIG. 1, a refrigeration system in accordance with one preferred embodiment of the present invention is generally indicated in its totality at  1 . In the preferred embodiment, the refrigeration system is a “walk-in” refrigerator. However, the present invention is useful with other known refrigeration systems. The refrigerator includes a refrigeration unit  2 , an access door  3 , and a plurality of interlocking panels  4 . The locations and arrangement of the refrigeration unit  2 , the access door  3 , and the panels  4  are exemplary and are not meant to limit the scope of the invention. For example, one skilled in the art would recognize that the refrigeration unit  2  could be side mounted, and the access door  3  could be mounted on other portions of the panels. 
     FIG. 2 shows a rear exploded view of the refrigerator system  1  of FIG.  1 . In FIG. 2, the panels  4  are exploded to illustrate how the panels are interlocked in order to form the refrigerator wall system. Ceiling panels  41  support refrigeration unit  2 . Ceiling panels  41  are attached to each other via fastening housings (not shown in FIG. 2) at fastener positions  5   a . Likewise, ceiling panels  41  are also attached to corner panels  42  and wall panels  43  at fastener positions  5   b  and  5   c , respectively. Corner panels  42  are attached to wall panels  43  at fastener position  5   d , and both the corner panels  42  and the wall panels  43  are attached to floor panels  44  at fastener positions  5   e  and  5   f , respectively. Similarly, floor panels  44  are attached to each other via fasteners at fastener positions  5   g.    
     FIG. 3 is an exploded view of one of the corner panels  42 . FIG. 3 shows the construction of the corner panels  42 , as well as illustrates the positioning of the male fastening housings  61  and female fastening housings  62  within the corner panel  42 . Comer panels  42  are formed by a molding process in which insulating material  101  is molded between metal skins  102 ,  103 . The metal skins  102 ,  103  are preferably made from aluminum, stainless steel, or galvanized steel, and may have a mold bond adhesive (not shown) on their inner surfaces in order to secure the insulating material  101 . Male fastening housings  61  and female fastening housing  62  are placed between the metal skins  102 ,  103  in male fastening positions  51 ,  53  and female fastening positioning  52 ,  54 , respectively, and molded in place during the molding process. Each male fastening housing  61  engages a female fastening housing on an adjacent abutting panel, and likewise each female fastening housing  62  engages a male fastening housing on an adjacent abutting panel. Thus, male fastening housings  61  positioned at male fastening positions  51  engage and connect to a female fastening housings on a wall panel  43  (FIG.  2 ), while male fastening housings  61  positioned at male fastening position  53  engage and connect to female fastening housings of a ceiling panel  41  (FIG.  2 ). Likewise, female fastening housings  62  positioned at female fastening positions  52  engage and connect to a male fastening housings on a wall panel  43  (FIG.  2 ), while female fastening housings  62  positioned at female fastening position  54  engage and connect to male fastening housings of a ceiling panel  41  (FIG.  2 ). 
     FIG. 4 shows the construction of one of the ceiling panels  41  of the preferred embodiment. Ceiling panels  41  are formed by a molding process in which insulating material  201  is molded between metal skins  202 ,  203 , and endcaps  204 . Male fastening housings  63 ,  65  are placed in male fastening positions  55 , and female fastening housing  64  in female fastening positioning (not shown in FIG.  4 ). Each male fastening housings  63  engages and connects to a female fastening housing on an adjacent ceiling panel, while male fastening housings  65  engage and connect to female fastening housings of a corner panel  42  or wall panel  43  (FIG.  2 ). Likewise, female fastening housings  64  engage and connect to male fastening housings on an adjacent abutting ceiling panel. 
     The remaining panels are constructed in substantially similar manners as the construction of the corner panels  42  and ceiling panels  41 . In each case, the male and female fastening housing are positioned so as to engage and connect to each other when the panels are placed adjacent to one another. 
     The fastening housings  61 ,  62 ,  63 ,  64 ,  65 , like all in the present invention, have a backing material (not shown) coated to at least one surface of the substrate used to make the fastening housing. In the preferred embodiment, all surfaces of the fastening housings have such a backer. The purpose of the backer is to improve the adherence of the fastening housings to the insulating materials, e.g., insulating material  101 ,  201 , in the individual panels  41 ,  42 ,  43 ,  44 . The substrates used for the fastening housings are preferably metals, and most preferably bare cold rolled steel, temper #4 with hardness range of B45 to B65. The backer may be any suitable material that more strongly adheres to the insulating material than does the substrate. A preferred backer includes a polymer material. More preferably, the backer contains a polyester. In the most preferred embodiment, the backer also contains an epoxy resin. A suitable material for the backer of the preferred embodiment is 12C126™ sold by Morton International of Chicippe, Massachusetts. The backer is preferably coated onto the substrate at a thickness of about 0.1 to about 0.5 millimeters, and most preferably at a thickness of about 0.2 to 0.3 millimeters. 
     The insulating materials  101 ,  201  may be any material capable of being molded. Preferably, the insulating material is a foam. In the most preferred embodiments of the invention, the insulating material is a urethane or polyurethane foam. A suitable material is Urethane XR1149R, sold by General Latex of Ashland, Ohio. 
     FIGS. 5 and 6 illustrate the male and female fastening housings of the preferred embodiment. FIG. 5 is top cross sectional view and FIG. 6 is a lateral cross sectional view. In FIGS. 5 and 6, male fastening housing  6   a  is embedded in the insulating material  301  of one of the panels of the refrigerator wall system  1  (FIG.  2 ), and female fastening housing  6   b  is embedded in the insulating material of an adjacent panel. Male fastening housing  6   a  includes a fastener casing  611  containing a rotatable hook member  615  at an engaging end of the male fastening housing  6   a , an actuating assembly  617 , and a stop pin  619 . Female fastening housing  6   b  includes a fastener casing  610  containing a catch pin  612  located at an engaging end of the female fastening housing  6   b . The hook member  615  of male fastening housing  6   a  is rotated between an open position (shown in phantom) where cut-out portion  623  of the hook member  615  rests against the stop pin  619 , and a closed position as shown in FIGS. 5 and 6. When adjacent panels are placed together, the hook member  615  engages the stop pin  612  and connects the male and female fastening housings  6   a  and  6   b  together, and thereby secures the adjacent panels. The details of the operation of the actuating unit  617  and the hook member  615  are well-known in the art have been omitted here, but can be found in U.S. Pat. No. 4,512,122, the entire disclosure of which is incorporated by reference herein. 
     The male and female fastening housings may also include wings  613  and  614 , respectively. The wings  613 ,  614  are located at a remote end of their respective housings opposite their engaging ends. The wings  613 ,  614  add to the pull-strength of their respective fastening housings in the insulation material. The male and female fastening housings  6   a  and  6   b  also may include apertures  621  and  622 , respectively, to facilitate flow of the molding material around the housings  6   a  and  6   b  during the molding process. 
     The present invention also embodies a method for making the fastening housings to be used in the refrigerator wall system. In the method of the present invention, backing material is added to a substrate material before the substrate is stamped to form the parts needed to assembly the fastening housings. The substrate is preferably a metal, and most preferably aluminum, stainless steel, or galvanized steel. Preferably the substrate is in the form of a metal sheet or metal coil. The backer may be applied to one side of the substrate, or to all sides of the substrate. As described above, the backing material chosen must have a stronger adherence to the insulating material than the substrate has to the insulating material. Suitable backers are polymers, such as polyesters, and/or epoxy resins. Most preferred is 12C126™ from Morton International of Chicippe, Mass. The substrate may be pre-treated before receiving the coating. A suitable treating agent is bonderite #902, iron-phosphate conversion coating process, sold by Parker of Henkel Services Technical of Madison Heights, Mich. 
     After the backing material has been coated onto the substrate, the parts for the fastening housings are stamped and assembled according to known methods in the art. 
     It should be readily understood by those persons skilled in the art that the present invention is susceptible of a broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. Accordingly, while the present invention has been described herein in detail in relation to its preferred embodiment, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended or to be construed to limit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof.