Patent Publication Number: US-2006010793-A1

Title: Indexing ribs for assembling a door, and door

Description:
FIELD OF THE INVENTION  
      The present invention is directed to a door having indexing ribs for aligning the door components during assembly. A peripheral door frame is provided having first and second stiles and first and second rails. The stiles and rails have opposing first and second sides. At least one channel is disposed in at least one of the sides. The channel has a base and angled sidewalls extending outwardly from the base to a corresponding one of the sides. The interior surfaces of first and second door facings are aligned with and secured to the first and second sides of the frame, respectively. At least one of the door facings has an indexing rib extending outwardly from its interior surface. The rib is aligned with and received in the channel.  
     BACKGROUND OF THE INVENTION  
      Molded doors are assembled using two door facings, which are typically secured to opposing sides of an internal frame that provides structural support. The frame typically includes stiles and rails located around the perimeter of the door. The facings may be molded from a wood fiber and resin composite, or a thermoset thermoplastic or thermoset composite material, such as a fiberglass compound. The door may also include a core material.  
      Thermoset thermoplastic or thermoset composite door facings typically are oversized during molding (i.e. out-of-press) compared to many frame sizes. The facings are then trimmed to accommodate the size of the frame to which the facings are to be secured. In this way, the same molded facing may be used for a variety of door sizes, and the manufacturer can be sure that the facing has at least the size required for the frame. Generally, a thermoset thermoplastic or thermoset composite door facing cannot be reused if it is not of sufficient size.  
      After the facings are trimmed to match a particular frame, they are carefully positioned on the frame, a process sometimes referred to as door lay-up. If the facings are not properly aligned with the corresponding frame, the edges of the resulting door may appear misaligned, rendering the door commercially unacceptable. In addition, if the facings are not properly trimmed, the appearance of the edges of the resulting door may be unacceptable. Therefore, accurate trimming of the facings prior to lay-up is required. Furthermore, careful alignment of the trimmed door facings onto the corresponding door frame is required. The trimming and alignment processes are relatively labor intensive, expensive, and subject to quality variations.  
      In an attempt to control product quality, various attempts have been made to effect proper positioning during door lay-up. Some attempts provide for door facings with hooked or L-shaped edges, which clip around the outermost portion of a perimeter frame. However, such designs do not ensure that the facings will be properly aligned unless they also are carefully molded to fit the frame prior to door lay-up. Other efforts include channels formed in the frame to receive a rib extending from the door facing. These efforts require precise control over the size and shape of the channel and rib, and also orientation of the rib with the channel. Such methods have not proven to be practical for door manufacture using thermoset thermoplastic or thermoset composite door facings, which are typically oversized out-of-press.  
      Therefore, there is a need for a door facing that is easily aligned with the frame during assembly.  
     SUMMARY OF THE INVENTION  
      The present invention is directed to a door. The door includes a peripheral door frame having first and second stiles and first and second rails. The stiles and rails have opposing first and second sides. At least one channel is disposed in at least one of the sides. The channel has a base and angled sidewalls extending outwardly from the base to the side. First and second door facings having interior surfaces are aligned with and secured to the first and second sides of the frame, respectively. At least one of the door facings has a ridge extending outwardly from the interior surface. The ridge is aligned with and received in the channel.  
      The present invention is also directed to a door facing. The facing comprises a generally rectangular member having first and second opposing major surfaces. The first major surface is adapted to be exteriorly disposed and the second major surface is adapted to be secured to a peripheral door frame. A series of spaced ridges are provided that extend outwardly from the second major surface, and are spaced from and parallel to a perimeter of the rectangular member. Each one of the spaced ridges has a semi-circular configuration in section.  
      The present invention also relates to a method of assembling a door. A peripheral door frame having opposing first and second sides and a channel disposed in each of the sides is provided. The channel has a base and angled sidewalls extending outwardly from the base to the side. First and second door facings are provided. Each facing has a ridge extending outwardly from an interior surface thereof. The ridge has a semi-circular configuration in section and extends outwardly from the interior surface to an apex of the ridge. The apex of the first facing is aligned with the channel in the first side. The first facing is positioned onto the first side by sliding the ridge into the channel until the apex is adjacent the base. The apex of the second facing is aligned with the channel in the second side. The second facing is positioned onto the second side by sliding the ridge into the channel until the apex is adjacent the base. The facings and frame are compressed to form a door. 
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       FIG. 1  is a perspective view of a door according to a first embodiment of the present invention;  
       FIG. 2  is a cross-sectional view of a portion of the door of  FIG. 1  taken along line  2 - 2  and viewed in the direction of the arrows;  
       FIG. 3  is an assembly view of the door shown in  FIG. 1 ;  
       FIG. 4  is a fragmentary sectional view of a portion of the door shown in  FIG. 1  taken along lines  4 - 4  and viewed in the direction of the arrows prior to compressing and trimming the door;  
       FIG. 5  is a fragmentary sectional view of a portion of a door similar to the view shown in  FIG. 4  with facings according to another embodiment; and  
       FIG. 6  is an elevational view of an interior surface of a facing showing ridge placement according to a preferred embodiment. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      As best shown in  FIGS. 1 and 2 , a door  10  according to the present invention includes a peripheral door frame  12 , with first and second door facings  14 ,  16  secured to opposing first and second sides  18 ,  20  of frame  12 , respectively. Preferably, first and second door facings  14 ,  16  are molded thermoset thermoplastic or thermoset composite door facings, such as fiberglass door facings. However, first and second door facings  14 ,  16  may also be molded wood composite facings, such as medium density fiberboard door facings.  
      As best shown in  FIG. 3 , frame  12  includes first and second stiles  20 ,  22  and first and second rails  24 ,  26 . Stiles  20 ,  22  may be laminated stiles having a composite core and solid wood outer edges. The composite core may be formed from fiberboard, wood fiber/resin composite material, plastic/wood fiber material, plastic/wood flour composite material, or any other suitable composite material. Alternatively, stiles  20 ,  22  may be formed from solid wood, or formed from a composite material without solid wood edges. Rails  24 ,  26  may also be formed from a composite material, such as fiberboard, wood fiber/resin composite material, plastic/wood fiber material, plastic/wood flour composite material, or any other suitable composite material. Alternatively, rails  24 ,  26  may be formed from solid wood.  
      First and second door facings  14 ,  16  are adhesively secured to opposing sides of the door frame  12 , as best shown in  FIGS. 1 and 2 . An interior surface  28  of facing  14  is secured to first side  18  of frame  12 . An interior surface  30  of facing  16  is secured to second side  20 . Facings  14 ,  16  are preferably adhesively secured to frame  12 .  
      At least one groove or channel  32  is formed in at least one of sides  18 ,  20 , as best shown in  FIG. 4 . Channel  32  may be routed, machined or molded into sides  18 ,  20 , depending on the construction of stiles  20 ,  22  and rails  24 ,  26  as well as manufacture preference. Channel  32  includes a base  34 , and angled sidewalls  36 ,  38  extending outwardly from base  34  to the corresponding side  18  or  20 . Preferably, angled sidewalls  36 ,  38  extend outwardly from base  34  at an angle of at least about 30°, more preferably at least about 45°, relative to side  18  or  20 . Preferably channel  32  is formed on opposing sides  18 ,  20  of each of stiles  20 ,  22  and rails  24 ,  26 . However, it should be understood that channel  32  may be formed in only one of sides  18 ,  20 . Alternatively, channel  32  may be formed in one or both sides of only stiles  20 ,  22 , or one or both sides of only rails  24 ,  26 .  
      As best shown in  FIGS. 2 and 4 , facings  14 ,  16  include indexing ribs or ridges  40  with a semi-circular configuration in section. Ridges  40  extend outwardly from interior surfaces  28 ,  30  to an outermost portion or apex  42 . Ridges  40  are aligned with and received in corresponding channels  32  during the door lay-up process. Due to the curved walls  44  of ridges  40 , ridges  40  tend to slide against angled sidewalls  36 ,  38  until apex  42  is adjacent base  34 , as best shown in  FIG. 2 . Interior sides  28 ,  30  of facings  14 ,  16  are preferably flush with sides  18 ,  20  of frame  12 , respectively, when apex  42  of ridges  40  are positioned in channels  32 .  
      Although channels  32  preferably include angled sidewalls  36 ,  38 , it would be apparent to one skilled in the art that channels  32  could have other configurations. Frame  12  may include channels having a complimentary configuration compared to the configuration of ridges  40 . For example, channels having a semi-circular configuration in section may be provided, which are complimentary to the configuration of ridges  40 . Alternatively, channels may be substantially rectangular in section. However, channels having angled or curved sidewalls tend to guide ridges  40  into proper position, even if facings  14 ,  16  are not precisely aligned with frame  12 .  
      Facings  14   a ,  16   a  having ridges  42   a  according to another embodiment are best shown in  FIG. 5 . Ridges  40   a  extending outwardly from interior surfaces  28   a ,  30   a . Each ridge  40   a  has a configuration corresponding to and complementary with the contour of channel  32 . Ridge  40   a  is aligned with and received in the corresponding channel  32  during the door lay-up process. Ridges  40   a  are formed in facings  14   a ,  16   a  to correspond to channels  32 , and include a crest  42   a  and angled sides  44   a ,  46   a  connected to and integral with crest  42   a  and interior surfaces  28   a ,  30   a . Sides  44   a ,  46   a  preferably extend at an angle of at least about 30° relative to interior surface  28   a  or  30   a . More preferably, sides  44   a ,  46   a  extend at substantially the same angle as angled sidewalls  36 ,  38 .  
      As best shown in  FIG. 6 , facings  14  (or  14   a ) preferably include a series of ridges  40  (or  40   a ) spaced from and parallel to the facing periphery. A plurality of relatively short ridges  40  permits a desired amount of flexibility of facing  14 . Some flexibility of facing  14  may be desirable if door  10  is prone to bowing slightly. For example, a certain amount of bowing of door  10  may be caused by thermal and/or moisture fluctuations. Accordingly, facing  16  has a ridge placement similar or identical to the ridge placement on facing  14 . If ridges  40  do not permit a sufficient amount flex when door  10  bows, facings  14 ,  16  may crack in portions not strengthened by ridges  40  (i.e. such as in the corners and/or central portions of door  10 ).  
      A series of relatively short ridges  40  proximate each edge  48 ,  50 ,  52 ,  54  permits a sufficient amount of flexibility of facing  14  (or  16 ). However, a sufficient number of ridges  40  should be provided proximate edges  48 ,  50 ,  52 ,  54  of facings  14 ,  16  to ensure that facings  14 ,  16  are easily aligned with channels  32 . In addition, each ridge  40  should have a sufficient length to ensure that it may be easily aligned within channels  32 , while still maintaining the proper position of facings  14 ,  16  on frame  12 . A sufficient number of ridges  40  having a sufficient length also provide structural integrity to facings  14 ,  16 .  
      An exemplary placement of ridges  40  on facing  14  is best shown in  FIG. 6 . Facing  14  includes six relatively short ridges  40  (or  40   a ) spaced from and parallel to edges  48 ,  50 . Facing  14  also includes three relatively short ridges  40  (or  40   a ) spaced from and parallel to edges  52 ,  54 . It should be understood that fewer or more ridges may be provided proximate each edge  48 ,  50 ,  52  or  54 . Furthermore, facing  14  need not include the same number of ridges  40  (or  40   a ) proximate edge  48  compared to edge  50 , or edge  52  compared to edge  54 . The length of ridges  40  (or  40   a ) may also vary depending on the number of ridges provided. However, ridges  40  (or  40   a ) preferably have a length of at least about one inch, more preferably at least about two inches.  
      If one relatively long ridge  40  (or  40   a ) extended proximate and parallel to each edge  48 ,  50 ,  52 ,  54  of facing  14 , whereby the length of ridge  40  (or  40   a ) was substantially the same as the corresponding edge  48 ,  50 ,  52  or  54 , flexibility of facing  14  may be limited. However, it should be understood that such a configuration for ridges  40  (or  40   a ) may be appropriate if bowing is not a consideration. One relatively long ridge  40  (or  40   a ) proximate each corresponding edge  48 ,  50 ,  52 ,  54  may be appropriate for some applications.  
      Facing  16  also preferably includes the same placement of ridges  40  as described above for facing  14 , as best shown in  FIG. 3 . Channels  32  are formed in first and second sides  18 ,  20  of frame  12 , as described above. Preferably, channels  32  are spaced from and parallel to the periphery P of frame  12 , as best shown in  FIGS. 2 and 4 . Channels  32  formed in first side  18  are preferably aligned with channels  32  formed in second side  20 . Channels  32  preferably extend the entire length of stiles  20 ,  22  and rails  24 ,  26 , as best shown in  FIG. 3 . In this way, ridges  40  (or  40   a ) may be easily aligned with channels  32 , even if facings  14 ,  16  are slightly different in size.  
      Ridges  40  (or  40   a ) are preferably formed on facings  14 ,  16  while facings  14 ,  16  are being molded. However, ridges  40  may also be separately formed, and adhered to conventional facings to form facings  14 ,  16 . Thermoset thermoplastic or thermoset composite door facings are typically oversized out-of-press, compared to the size of many doorframes. However, facings  14 ,  16  need not be trimmed prior to door lay-up because precise placement of facings  14 ,  16  on frame  12  is achieved by aligning ridges  40  with channels  32 . First facing  14  is positioned so that its interior surface  28  is exposed. First side  18  of frame  12  is aligned with facing  14  so that channels  32  are aligned with ridges  40 . Because of the curvilinear configuration of walls  44  and the angular configuration of sidewalls  36 ,  38  of channels  32 , frame  12  tends to slide into proper position on facing  14  even if ridges  40  are slightly misaligned with channels  32 . Ridges  40  tend to slide against sidewalls  36 ,  38  until apex  42  (or crest  42   a ) is aligned with and preferably contacts base  34 , as best shown in  FIG. 2 . Second facing  16  may then be aligned with second side  20  of frame  12  in the same manner. Facings  14 ,  16  are preferably adhesively secured to frame  12 , though fasteners such as screws may also be used.  
      Thus, channels  32  and ridges  40  provide a tongue and groove door assembly system, which may be used to easily locate and align the facings  14 ,  16  on the stiles  20 ,  22  and rails  24 ,  26  during lay-up. After facings  14 ,  16  are properly aligned with frame  12 , the resulting components may be compressed to form door  10 , as best shown in  FIG. 1 .  
      The perimeter of door  10  may then be trimmed to a desired size, as shown by trim line T in  FIGS. 4 and 5 . Thus, facings  14 ,  16  need not be precisely sized prior to door lay-up. Note that a portion of both the facings  14 ,  16 , as well as the perimeter P of frame  12  may be trimmed to size without removing ridges  40  and channels  32 .  
      The present invention therefore eliminates the need for pre-trimming facings prior to lay-up, thereby decreasing manufacturing costs. For example, the present invention reduces manufacturing costs, and reduces manufacturing time, compared to the cost and time for manufacturing a similar door that does not include channels  32  and ridges  40 . In addition, facings  14 ,  16  require less handling, which reduces the possibility of damage. It will be understood to one skilled in the art that the present invention is applicable to any type of door, including interior doors, exterior entry doors, and cabinet doors for furniture, kitchen cabinets, and the like.  
      Certain aspects of the present invention have been explained according to preferred embodiments. However, it will be apparent to one of ordinary skill in the art that various modifications and variations of the disclosed embodiments may be made without departing from the scope or spirit of the invention. Thus, it is intended that the present invention cover all such modifications and variations, provided they come within the scope of the following claims and their equivalents.