Patent Abstract:
A door panel is disclosed that includes first and second doorskins each formed from two metal stile elements including a longitudinal flange and two rail elements including a pair of U-shaped projections defining narrow grooves, wherein the rail elements are connected to the stile elements by placing the stile element flanges into the rail element grooves and, piercing the U-shaped projections to form a permanent mechanical bond between the stile and rail elements. A method of forming such a door panel is also disclosed.

Full Description:
FIELD OF THE INVENTION 
     The present invention is directed toward a door panel comprising two multi-component doorskin subassemblies and a method of assembling same, and more specifically, toward a door panel comprising a plurality of folded metal elements permanently interconnected to form first and second doorskins, which doorskins are attached to stile and rail members, and a method of assembling same. 
     BACKGROUND OF THE INVENTION 
     Traditional wooden doors are formed from two vertical, parallel members called stiles connected at their top and bottom ends by two horizontal members called rails. One or more central panels are then connected between the stiles and rails to form a door. In a newer method of forming a door a frame of stiles and rails is provided, and first and second doorskins are attached to the outer faces of the frame. This method requires less labor and provides a hollow door interior that can be filled with insulation. In order to give the appearance of a traditional door, the doorskins are often formed with a contoured inner section and a smooth periphery that resemble interconnected rails and stiles. 
     Light weight metal door panels such as those used for storm doors or screen doors are often formed from first and second metal doorskins mounted on opposite sides of parallel stiles. The stiles are generally wooden, and hinges can be attached to one stile (the hinge stile) and a handle and/or latch to the other stile (the latch or strike stile) to form a door panel. For typical doors of this type, the upper halves of the center portions of the doorskins may be cut out to receive a lite such as a windowpane or a screen. In other door panels, substantially all the center portions of the doorskins are removed to accommodate a larger lite. Formed in this manner, the doorskins have a smooth outer finish and do not provide the appearance of a door formed with rails and stiles. 
     U.S. Pat. No. 4,546,585 shows one attempt to form a metal door that appears to be formed of rails and stiles. In this patent, a wooden frame is provided, and a metal covering or cladding is attached to the wooden frame. The cladding is formed from a number of separate elements that are interconnected in a temporary manner and attached to the wooden frame. Foam insulation is then injected into the temporary assembly to permanently secure all the elements. While this reference provides a door with a satisfactory appearance, it is unnecessarily difficult to assemble, and its individual elements must be carefully aligned while they are being joined. Moreover, because the elements that form the doorskins are not held together in a permanent manner until the finished assembly is filled with foam insulation, the doorskins may fall apart if handled roughly or stored and manipulated extensively before they are used in a door panel. 
     It would therefore be desirable to provide a metal door panel having interconnected stile and rail elements that is easy to manufacture and that does not need to be filled with foam insulation in order to permanently secure all its elements. 
     SUMMARY OF THE INVENTION 
     These and other problems are overcome by the present invention which comprises a door panel having first and second stiles to which are mounted first and second doorskins formed from interconnected, preferably metal, elements. The elements that overlay the stiles each include a longitudinally extending flange along a first edge while the rail elements that connect the stile elements include grooves for receiving the stile element flanges. Advantageously, the flange-in-groove connection helps keep the elements aligned while they are being assembled and, when the connection is pierced by a sharp tool, also provides a very secure joint. 
     In a preferred embodiment, the stile elements each include a longitudinally extending L-shaped projection along a second edge parallel to the flange, the short leg of the “L” engaging the longitudinal slot in a stile to secure the doorskin to the stile. The longitudinal grooves of the rail elements are formed inwardly from the end edges of the rail elements so that an end portion of the rail element overlies a portion of the stile element when the stile flange is received in the rail element groove. The groove includes an inner leg disposed toward the middle of the rail element and an outer leg that is shorter than the inner leg by an amount equal to the thickness of the stile element. In this manner, when the stile element flange is received in the rail element groove, the face of the stile element opposite the flange and the face of the rail element opposite the groove will be substantially coplanar. 
     After the stile element flanges are received in the rail element grooves, the grooves are pierced by a sharp tool to drive a portion of the groove inner leg against and preferably through the flange and into the outer leg of the groove. This forms a permanent connection between the rail elements and stile elements. Because the rail and stile elements of the doorskins are permanently connected in this manner, the doorskins can be preassembled and stored indefinitely until they are needed for a door assembly and are structurally sound at this stage of manufacture, before they are incorporated into a door panel filled with insulating material, as was necessary to permanently bond the doorskin elements together in the prior art. 
     Once two doors skin have been formed, the short legs of the L-shaped projections on the stile elements are inserted into longitudinal slots on parallel stiles and secured thereto to form a door. Rails may also be added to connect the stiles, and a lite frame may be provided at the center part of the door to hold a window or screen. The door can also, optionally, be filled with foam insulation. 
     It is therefore a principal object of the present invention to provide a door panel comprising a doorskin formed from a plurality of interconnected elements. 
     It is another object of the present invention to provide a method of assembling a doorskin by permanently interconnecting a plurality of metal elements. 
     It is a further object of the present invention to provide a door panel comprising a doorskin formed from permanently interconnected stile elements and rail elements. 
     It is still another object of the present invention to provide a doorskin formed from stile elements having flanges and rail elements having grooves wherein the stile element flanges are received and retained within the rail element grooves. 
     It is still a further object of the invention to provide a doorskin formed from stile elements and rail element configured to be easily alignable during an assembly process. 
     In furtherance of these objects, a door assembly is provided that includes a hinge stile and a latch stile each having a longitudinal groove, and first and second doorskin assemblies each having a central opening connected to opposite sides of the hinge stile and the latch stile, wherein each of the doorskin assemblies is formed from first and second stile elements and first and second rail elements connected between the first and second stile elements. The first and second stile elements each have a first side including an integrally formed L-shaped projection and a second side including a flange having first and second ends, and the first and second rail elements each comprise a planar body portion and a first end having a first edge and a second end having a second edge and a first U-shaped projection defining a groove and extending from the first end near the first edge and a second U-shaped projection defining a groove and extending from the second end near the second edge. The first end of the first stile element flange is received in the first rail element first end groove and permanently secured thereto by piercing and the first end of the second stile element flange is received in the first rail element second end groove and permanently secured thereto by piercing, and the first U-shaped projection includes an inner leg having a first length and an outer leg having a second length less than the first length. 
     A method of forming a door assembly is also disclosed that includes the steps of providing a first stile element having a first side including an L-shaped projection and a second side including a flange having a first end and a second end; providing a top rail element having a planar central portion and first and second ends each having a narrow groove; inserting the first end of the first stile element flange first end into the first rail element first end narrow groove; piercing the first rail element groove to drive a portion of the wall defining the groove into the,first stile element flange first end in the groove; providing a bottom rail element having a planar central portion and first and second ends each having a narrow groove; inserting the second end of the first stile element into the bottom rail element first end narrow groove; piercing the bottom rail element groove to drive a portion of the wall defining the groove into the first stile element flange second end in the groove; providing a second stile element having a first side including an L-shaped projection and a second side including a flange having a first end and a second end; placing the first end of the second stile element flange in the top rail element second groove; placing the second end of the second stile element flange in the bottom rail element second groove; piercing the second rail element groove to drive a portion of the wall defining the groove into the second stile element first end flange in the groove; piercing the second stile element groove to drive a portion of the wall defining the groove into the second stile element flange second end in the groove; attaching a latch stile to the first stile element L-shaped projection; attaching a hinge stile to the second stile element L-shaped projection; and attaching a doorskin to the latch stile and the hinge stile. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects and advantages of the invention will be better understood upon a reading and understanding of the detailed description of the invention provided below together with the following drawings. 
     FIG. 1 is a front elevational view of a door assembly according to the present invention. 
     FIG. 2 is a perspective view of one of the stile elements of the door assembly of FIG.  1 . 
     FIG. 3 is a perspective view of one of the rail- elements of the door assembly of FIG.  1 . 
     FIG. 4 is a sectional plan view taken along line  4 — 4  in FIG.  1 . 
     FIG. 5 is a sectional plan view taken along line  5 — 5  in FIG.  1 . 
     FIG. 6 is a detail view of the junction between the stile element of FIG.  2  and the rail element of FIG.  3 . 
     FIG. 7 is a perspective view of a portion of the junction shown in FIG.  6 . 
     FIG. 8 is a sectional side elevation taken along line  8 — 8  in FIG.  1 . 
     FIG. 9 is a sectional side elevation taken along line  9 — 9  in FIG.  1 . 
     FIG. 10 is a plan view of an alternate embodiment of one end of a rail element for connection to the stile elements of the door assembly of the present invention. 
     FIG. 11 is a detail view of an alternate embodiment of the junction between the stile element of FIG.  2  and the rail element of FIG.  3 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting same, FIGS. 1 and 4 show a door assembly  10  comprising a hinge stile  12  having a longitudinal slot  13 , a strike or latch stile  14  having a longitudinal slot  15 , a top rail  16 , a bottom rail  18  and a first metal doorskin  20  having a lite  22 . The stiles and rails are preferably made from a lightweight wood, but could be formed from other materials known in the art without departing from the scope of this invention. A second doorskin  24  having a lite  26  is shown in FIG.  5 . Doorskins  20  and  24  are mirror images of one another, but are otherwise identical, and only doorskin  20  will be described hereafter, it being understood that doorskin  24  is composed of identical parts. 
     Doorskin  20  includes a plurality of interconnected elements, preferably formed from a sheet of metal such as steel or aluminum, that are attached to stiles and rails to form a door panel. Specifically, a first stile element  30  overlies hinge stile  12 , a second stile element  32  overlies strike stile  14 , a first or top rail element  34  overlies top rail  16 , and a second or bottom rail element  36  overlies bottom rail  18 . 
     Stile element  30  is shown by itself in FIG.  2  and comprises a planar central section  38 , a first side  40  and a second side  42 , an L-shaped projection  44  extending from the edge of first side  40  and including a long leg  46  and a short leg  48 , and a flange  50  extending from second side  42  at a right angle to central section  38 . Stile element  30  also includes a first end  52  having a flange  53  and a second end  54  having a flange  57 . Second stile element  32  includes one or more openings  55  shown in FIG. 1 for accommodating locking and latching hardware in a well-known manner, but is otherwise substantially identical to first stile element  30 . 
     Rail element  34  is shown by itself in FIG.  3  and includes a planar central section  56 , a top edge  58  having a flange  59 , a bottom edge  60  having a bottom flange  61 , a first side  62  having an edge  64  and a second side  66  having an edge  68 . First and second U-shaped projections  70  extend substantially between top edge  58  and bottom edge  60  and comprise inner legs  72  facing planar central section  56 , outer legs  74  and a narrow slot  76  defined in part by these inner and outer legs. For reasons to be described in more detail hereinafter, the outer legs  74  are shorter than the inner legs  72  by an amount equal to the thickness of the material from which the rail and stile elements are formed. First side  62  of rail element  34  and second side  66  of rail element  34  are generally coplanar, while central section  56  lies in a different plane parallel to the plane of the first and second sides. The width of narrow groove  76  is approximately equal to the thickness of the sheet metal material, and second rail element  36  is substantially identical to first rail element  34 . 
     Doorskin  20  is assembled by arranging first stile element  30  and second stile element  32  in parallel on a support surface (not shown) with flanges  50  facing upward, facing each other, and spaced apart by the distance between narrow grooves  76  of first rail element  34 . First rail element  34  is then placed on the first ends of the stile elements so that flanges  50  of stile elements  30  and  32  are received into narrow grooves  76  of the first rail element and so that top edge  58  of the first rail element is generally aligned with first end  52  of stile element  30 . Second rail element  36  is placed on the other ends of the stile elements in a similar manner. Because the distance between the U-shaped projections is known, the proper spacing between the stile element flanges can readily be maintained, and the stile and rail elements can be kept in proper alignment while they are permanently secured. To secure the elements of doorskin  20  to one another, a tool is used to pierce the U-shaped projections to form dimples  78  therein which can be seen in FIGS. 6 and 7. The dimples  78  preferably extend through inner legs  72  and into flanges  50  and may also extend partially into outer legs  74  to form a secure connection between the stile elements and the rail elements. Dimples formed along the length of the U-shaped projection at intervals of about 0.75 inch provide adequate strength for the panel. Second doorskin assembly  24  is formed in the same manner. The dimples may alternately extend inwardly through both the inner and outer legs as shown in FIG.  11 . 
     Because the outer legs of the U-shaped projections are shorter than the inner legs by an amount equal to the thickness of the material used for the stile elements, the surfaces of the stile elements and rail elements opposite the projections will be generally coplanar and provide a smooth finished appearance for the door assembly. Moreover, sides  62  and  66  of first rail element  34  overlie a portion of the planar central portions of the stile elements to provide increased rigidity to the doorskin in the area of the above-described joints. 
     To form a door assembly from the doorskins, hinge stile  12  is attached to first stile element  30  by inserting short leg  48  of L-shaped projection  44  into the longitudinal slot  13  of hinge stile  12 ; strike stile  14  is attached to second stile element  32  in a similar manner as shown in FIG.  4 . Top and bottom rails  16  and  18  are then connected between the stiles with flanges  59  on the first and second rail elements helping to position the top and bottom rails as shown in FIGS. 8 and 9. A second doorskin  24 , formed in the same manner as the first doorskin, is attached to the opposite side of this partial assembly. A lite frame  80  having clips  82  shown in FIGS. 1 and 5 is next attached to the portions of flanges  50  extending between the first and second rail elements, and optionally, the entire assembly may be filled with a foam insulation  84  in a conventional manner. 
     FIG. 10 shows a modified rail element  34 ′ which may provide a more rigid door assembly and help prevent leakage of foam insulation injected between the doorskins when used in the door panel described above. Elements in this figure that correspond to elements of the first embodiment are identified by the same reference numerals in this figure but include primes. In this embodiment, a portion  63  of side  62 ′ of first rail element  34 ′ is bent toward the plane of central portion  38 ′ at an angle α of about two to four degrees. When rail element  34 ′ is attached to the stile elements as described above, portions  63  press firmly against the central portion of the stile element which helps to reduce flexing in the assembly. 
     The subject invention has been described herein in terms of preferred embodiments; various obvious modifications and additions to these embodiments will become apparent to those skilled in the relevant arts upon a reading and understanding of this disclosure. All such modifications and additions are considered a part of this invention to the extent that they fall within the scope of the several claims appended hereto.

Technology Classification (CPC): 4