Abstract:
A wall system including a plurality of rectangular rigid prefinished panels mounted on a wall support structure with main runners and cross runners. The main runners serve to lock the panels onto the support structure and with the cross runners serve to prevent the panels from warping due to adverse moisture conditions. The main runners are configured to space the panels from the wall support structure to encourage uniform humidity conditions at the front and rear of the panels. Clips that secure the panels to the main runners are fixed adjacent the top and bottom panel edges at different setoffs to obtain an advantageous nesting of panels for reduced packaging volume.

Description:
This application is a continuation of Ser. No. 09/220,561, filed Dec. 23, 1998 now U.S. Pat. No. 6,202,377. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to wall construction and, in particular, to a wall system formed of an array of prefinished rectangular panels mechanically held on a wall framework. 
     PRIOR ART 
     It is known to construct a wall surface for a room or other structure with a plurality of prefinished rectangular panels. (As used herein, the term “rectangular” includes “square”.) Such constructions using a real wood veneer, for example, can achieve a custom high-quality appearance with moderate material and labor costs. Under varied circumstances, prior art panels such as those with a particle board core have exhibited a tendency to warp after installation. This warpage detracts from the appearance of the installation and if severe enough, can require remedial work. It is believed that warpage can be induced by moisture in adhesives used to hold the panels on a substrate or support wall and/or by different moisture levels between the front and rear faces of a panel where air circulation is limited at the back of the panels. 
     SUMMARY OF THE INVENTION 
     The invention provides a method and components for an improved wall construction of the type comprising an array of prefinished rectangular panels. In accordance with the invention, the panels are mechanically attached to a supporting wall frame or other structure and the attachment elements are arranged to constrain the panels against warpage. 
     In a preferred embodiment, the panels are stiffened by rigid runners, preferably made of suitable metal elements, extending substantially along the full length of their edges. The upper and lower edges of the panels are positively secured to the wall frame or other support structure by horizontal runners while the vertical panel edges are located to the wall frame indirectly by the close proximity of the ends of vertical runners to the horizontal runners. 
     More specifically, elongated panel mounting clips, preferably roll formed members of steel or other suitable metal, are factory attached to the rear or back side of each panel adjacent its upper and lower edges. The clips have a “Z”-like cross section to provide a flange that with the adjacent surface area of the panel forms a groove. These groove constructions at the top and bottom of a panel tightly receive flanges of corresponding main runners to fix the panel in its desired location on the wall framework. 
     As disclosed, the “Z” clips or brackets at the upper and lower panel edges are preferably at different offsets from their respective edges. This arrangement has the advantage of minimizing shipping bulk and, consequently, cost. The cross runners that stabilize the vertical panel edges in the disclosed embodiment are formed as splines that each tightly fit as a tongue into opposed grooves of adjacent panels. The cross runners or splines thus, in addition to reducing the tendency of the panel to warp also align the edges of adjacent panels to one another to improve the appearance of the installation. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a fragmentary perspective view of a wall constructed in accordance with the invention; 
     FIG. 2 is an enlarged end view of a main runner; 
     FIG. 3 is an enlarged end view of a cross runner and portions of adjacent panels; 
     FIG. 4 is a cross sectional view of the wall of FIG. 1 taken in a vertical plane; 
     FIG. 5 is a cross sectional view taken in a horizontal plane at an inside and an outside corner of a wall constructed like that of FIG. 1; 
     FIG. 6 is a cross sectional view taken in a horizontal plane of an end of a wall constructed like that of FIG. 1; 
     FIG. 7 is an end view of a plurality of panels stacked for shipment and/or storage; 
     FIG. 7A is a plan view on a reduced scale showing the rear face of a panel having clips mounted thereto; 
     FIG. 8 is an end view of an alternative main runner; and 
     FIG. 9 is an end view of an alternative cross runner. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings, a wall system  10  constructed in accordance with the invention includes a plurality of rigid rectangular panels  11  attached to a wall support structure or framework  12  represented by vertical studs  13  covered by gypsum board or drywall  14 . The panels  11  are mechanically attached to the framework studs  13  with elongated clips  16  that grip horizontal runners  17 . Adjacent vertical edges of the panels  11  are mutually aligned by cross runners  18 . 
     The panels  11 , which can be identical for the most part, are an assembly of a flat, rigid board-like unit  19  and a pair of the clips  16  attached to a rear face  22  of the board  19 . A panel board  19  can comprise any suitable construction material and in the preferred embodiment comprises a laminate of two outer face layers  26  and  27  and an intermediate core  28 . The core can be commercially available particle board that consists primarily of wood particles bonded together with known materials. This particle board and similar cellulose based materials are particularly suited for the present invention since they afford both economy and adequate tensile and compressive strength. An exterior or front surface  29  of the face  27  typically has a final finish when it leaves the panel factory. For example, where the face or layer  27  is a wood veneer, it can be sanded, stained, and lacquered or otherwise prefinished before shipment from the factory where the panel  11 , as described, is manufactured. The panels  11  have nominal common face dimensions of, for example, 2 foot×2 foot square, or 2 foot high×4 foot wide. It will be understood, however, other suitable dimensions are envisioned. 
     Referring to FIGS. 7 and 7A clips  16  fixed to the rear faces  22  of the panel board  19  can be roll formed sheet steel or aluminum, for example. In the illustrated construction, the clips  16  are identical at both the top and bottom edges of a panel board  19  and have a length equal to or slightly shorter than the horizontal length of the panel board. The cross section of a clip  16 , as shown in FIG. 7, is “Z”-shaped albeit somewhat shortened and broadened with generally planar flanges  31 ,  32  and an intermediate web  33 . One flange  31  is secured against the panel board  19  either directly abutting it or adhered to it. The clips  16  are fixed to the rear panel face  22  with suitable means such as mechanical fasteners in the form of screws, staples or the like and/or an adhesive fastening medium. The other flange  32  has its edge remote from the web  33  bent outwardly slightly forming a lip  34  which facilitates assembly with a main runner  17  as explained below. At an upper edge  36  of a panel board  19 , the clip  16  is closely adjacent the edge while at a lower edge  37  the clip is adjacent but spaced a predetermined distance from this edge. 
     Vertical edges  38  of the panel boards  19  are provided with a groove  39  running their full length and preferably centered in the thickness of the board and having a round bottom to reduce any tendency of a stress induced fracture in this area. By way of example, the panel boards  19  can have representative thicknesses of ¾″, ⅝″, or ½″ with the thicker dimensions being preferred where greater strength is required. The grooves  39  can be ⅛″ wide and approximately {fraction (9/16)}″ deep. 
     The illustrated main horizontal runners  17  are extruded aluminum members with an irregular, asymmetrical cross section. This cross section, with particular reference to FIG. 2, includes a central channel section  41  with a web  42  and flanges  43 . The flanges have extended portions  44 ,  46  that project oppositely of one another in a common plane parallel to but spaced from the plane of the web  42 . The main runner cross section also includes an extension  47  of a lower one of the flanges  43 . The extension has ribs  48 ,  49  that are useful in gauging the vertical gap between adjacent panels  11 . The main runners  17  have a length preferably at least equal to the combined horizontal length of two panels  11 , and can be, for example, 8, 10 or 12 feet long. 
     FIG. 3 illustrates an end view of a cross runner  18 . As shown, the cross runner  18  has an irregular cruciform shape in section. One part  51  of the cruciform has corrugations  52  while another part  53  has ribs  54 ,  55 . The illustrated cross runner  18  is made as an aluminum extrusion. The cross runners  18  have lengths generally equal to the vertical height of a panel  11 . 
     The panels  11  are installed on the wall support structure  12  by assembling a first row of panels  11 , typically starting at floor level, along the base of the supporting wall structure with a cross runner  18  assembled in the opposed vertical slots or grooves  39  of adjacent panels  11 . The horizontal spacing between the panels  11  is determined by abutting the panel edges  38  against the cross runner ribs  54 . The panels  11  are mechanically locked in position relative to the support structure  12  by positioning the lower flange portion or extension  46  of a main runner  17  into a groove or slot  56  formed by the clips  16  adjacent the upper edges  36  of the panel boards  19  and then securing the main runner to the support structure. In the illustrated case, this, is accomplished by driving a self-tapping screw  61  through the web  42  into each of the studs  13 . A shallow groove  62  can be formed in the profile of the inside of the channel  41  to locate and stabilize the screw  61  as it is driven. The lower edges  37  of the first course or row of panels  11  can be secured to the support structure by suitable mechanical or adhesive means or other known fastening means. If desired, a “Z” strip with the proportions of the main runner channel  41  and upper flange portion or extension  44  can be used for this purpose. It should be understood that where desired, the main runners  17  can be secured directly to an open framework made up of studs or other elements not covered by gypsum board or other board material. 
     After a sufficient length of a main runner or runners  17  has been set and fixed to the wall support structure  12  with the lower flange area  46  received in the slot or groove  56  formed by the clips  16  and adjacent rear face areas  22  of the panel boards  19 , a second course or row of panels  11  is installed above the first row. This is accomplished by manipulating the panels  11  to cause the upper flange  44  of the main runner to be received in a slot or groove  57  formed between the lower clip  16  and the rear faces  22  adjacent the lower edges  37  of the second row of panels  11 . Each panel  11  is forced downwardly until the upper flange  44  of the main runner  17  is fully received in the groove  57  created between the clip  16  and panel board  19  and the lower edge  37  contacts the rib  48  of the main runner. As before, a cross runner  18  is inserted in the opposed vertical grooves  39  of adjacent panel boards  19 . When this second course of panels  11  has been put in place, the process of securing it to the wall structure with a main runner  17  at the upper panel edges  36  is repeated. In the same manner, subsequent rows or courses of panels  11  are positioned on the wall with cross runners  18  disposed between the panels and main runners  17  located at the lower and upper edges  36 ,  37  of the panels. This process is repeated until the wall support structure  12  is covered by the panels  11  to the extent desired. 
     The effective thickness of the cross runner part  51  that is received in a groove  39  is proportioned to provide an interference with the groove to ensure a tight fit therewith. It will be seen that the cross runners  18  serve to align adjacent panel edges  38  to one another. As shown in FIG. 7, the clips  16  can be made with the flange  32 , in its free state, close to the rear face  22  so that a somewhat tight interference fit is achieved between this flange and the main runner flange  44 . Inspection of FIG. 4 reveals that the channel-like structure of the main runner  17  serves to space the panels  11  away from any subwall such as that represented by the gypsum board  14 . This spacing ensures that adequate air circulation exists around the panels so that any tendency of a differential in moisture content between the front and back of the panels  11  is reduced and, consequently, a tendency for the panels to warp from moisture conditions is reduced. It will be understood that panels such as the illustrated panels  11 , formed of wood or similar cellulose based materials, can be particularly susceptible to moisture-induced warping. The disclosed wall system  10  is effective in overcoming the problem of warpage of such panels since the main and cross runners  17 ,  18  which are relatively rigid and free of moisture related warpage, engage substantially the full perimeter of each panel and serve to maintain the corresponding edges of the panel in a common plane thereby preventing visually distracting warpage. 
     FIG. 5 is a cross section of a wall system constructed in accordance with the invention taken in a horizontal plane to illustrate metal corner accessories  63 ,  64  at inside and outside corners, respectively. The accessories,  63 ,  64  can be aluminum extrusions and can include channel structures  66 ,  67  to appropriately space the panels  11  from the subwall. FIG. 6 similarly illustrates an aluminum extrusion accessory  68  for the end of a wall. 
     With reference to FIG. 7, the offset of one of the clips  16  from its adjacent edge  37  allows a pair of panels  11  to be stacked rear face to rear face and offset clip to non offset clip so as to reduce the effective bulk of the panels and thereby reduce storage and shipping expense. 
     FIGS. 8 and 9 illustrate modified forms of a main runner  117  and a cross runner  118 . In these arrangements, a flange extension  147  and cruciform part  153  have channels  71 ,  72 , respectively, which exist between edges of associated panels  11  and are adapted to receive the stem of a decorative strip having a T-shaped cross section as is known in the art. 
     It should be evident that this disclosure is by way of example and that various changes may be made by adding, modifying or eliminating details without departing from the fair scope of the teaching contained in this disclosure. The invention is therefore not limited to particular details of this disclosure except to the extent that the following claims are necessarily so limited.