The present invention relates to a wood composite panel, such as a door facing, having a major planar portion, at least one panel portion, and an extending contoured portion surrounding the panel portion and interconnecting the major planar portion and the panel portion. The contoured portion has a vector angle and a draw depth that achieve a satisfactory stretch factor. The present invention also relates to a door having the disclosed wood composite door facings, and methods of forming the facing and door.
Hollow core doors simulating natural, solid doors are well known in the art. Such doors typically include a peripheral frame, with two door facings secured to opposing sides of the frame. The door facings may be formed from wood composite, such as hardboard, medium density fiberboard, oriented strandboard, wood plastic composites, and the like. The facings may have a smooth, planar surface, a textured surface and/or a contoured surface. Contoured, or molded, door facings are often formed to have portions simulating stiles, rails and panels, as found in traditional wooden rail and stile doors.
Typically, the door also includes a core, which fills the internal void formed between the two opposing facings. The core may be formed from corrugated pads, low density fiberboard, particleboard, foamed insulation, or some other materials. For example, an expanding insulating foam material may be applied through holes drilled through the peripheral frame to provide access to the internal void. The core provides rigidity and structural integrity to the door, as well as desired thermal and acoustic characteristics of the door. However, the use of a core increases manufacturing costs.
Door facings formed from sheet molding compound (SMC) with expensive glass fibers, or similar resin based materials, may be formed to have deep draw contoured portions, given the moldable characteristics of such materials. However, the moldability of wood composites requires consideration of certain factors and parameters different than those addressed for SMC materials. Typically, a wood composite panel is formed from a loose mat of very short cellulosic fibers or particles. The mat may be 2 inches thick or more prior to compression. The mat is then compressed to form the facing or panel. As the mat is compressed, the fibers do not flow. Rather, the fiber mat is stretched, particularly in contoured portions. Contoured portions having steep sidewalls or curves, or deep draw depths, may result in surface cracks or defects due to the stretching of the fiber mat during compression.
The present invention is directed to a door having a peripheral frame and first and second wood composite door facings. Each facing has a peripheral portion with a surface secured to opposite sides of the frame. Each facing includes at least one inwardly disposed portion integral with the peripheral portion. The inwardly disposed portion of the first facing is aligned with and abuts the inwardly disposed portion of the second facing. At least one of the facings has a commercially acceptable exterior surface. The door may also include a core disposed between and adhered to the interiorly disposed surfaces of the first and second facings.
The present invention also discloses a door comprising a peripheral frame having first and second sides and first and second wood composite door facings. Each facing has a major planar surface having an exterior surface and an interior surface secured to the first and second sides, respectively, and at least one panel portion. An inwardly extending contoured portion surrounds the panel portion and interconnects and is integral with the major planar portion and the panel portion. The contoured portion has a vector angle and a draw depth that achieve a satisfactory stretch factor as shown in
Also disclosed is a wood composite door facing. The facing includes a major planar portion, at least one panel portion, and an inwardly extending contoured portion. The major planar portion has a first surface adapted to be exteriorly disposed and a second surface adapted to be interiorly disposed. The contoured portion surrounds the panel portion and interconnects and is integral with the major planar portion and the panel portion. The contoured portion has a vector angle and a draw depth that achieve a satisfactory stretch factor as shown in
The present invention also relates to a method of forming a wood composite door facing. A mold having a lower die and an upper die is provided. The lower die has a flat portion and at least one die cavity. The upper die has a flat portion and at least one downwardly extending contoured design complementary to the at least one die cavity. A cellulosic mat is disposed between the lower and upper dies. The mat is compressed between the lower and upper dies to form a door facing having a contoured portion and a planar portion. The contoured portion extends inwardly from and relative to a first surface of the planar portion adapted to be exteriorly disposed and opposite to a second surface adapted to be interiorly disposed. The contoured portion has a vector angle and a draw depth that achieve a satisfactory stretch factor as shown in
A method of forming a door is also disclosed. A peripheral frame having first and second sides is provided. A first door facing is secured to the first side of the frame. The first facing has a contoured portion and a planar portion. The contoured portion has a vector angle and a draw depth that achieve a satisfactory stretch factor as shown in
As best shown in
As best shown in
Although the embodiment shown in
During manufacture of door 10, the periphery of interiorly disposed surface 20 of first facing 14 is secured to wood frame 12 using adhesive, fasteners, or the like. An adhesive, such as poly vinyl acetate and/or hot melt glues such as polyurethane reacted (PUR), may then be applied to the interior surface 21 of base 32 of first facing 14. Preferably, interior surface portions 21 have a sufficient length to permit juxtaposed surface portions 21 to be securely adhered together so that rigidity and structural integrity are provided. Second facing 16 (or 16A) is then secured to frame 12 using adhesive, fasteners, or the like, so that base 32 of second facing 16 is aligned with base 32 of first facing 14. In this way, the surface portions 21 are ensured to abut. The resulting assembly is then compressed, thereby securely adhering the facings 14, 16 to frame 12. The adhesive between surface portions 21 penetrates facings 14, 16, so that there is a glue bond without a gap between the interior surface portions 21 of base 32.
In order to achieve satisfactory surface quality of first surface 18, the angle at which angled areas 28, 30 extend relative to major planar surface 24 and panel portion 22 is adjusted depending on the draw depth of contoured portion 26. As best shown in
Angled areas 28, 30 may extend downwardly from major planar surface 24 and panel portion 22, respectively, at the same angle, as best shown in
Likewise, a vector angle V2 of angled area 30 is determined by striking a straight line from a first point 3 on panel portion 22 directly adjacent the upper portion of angled area 30, and a second point 4 on base 32 directly adjacent the lower portion of angled area 30. First and second points 3, 4 are taken at the caliper midpoint of panel portion 22 and base 32, respectively. A vector angle V2 is the angle between the vector line from points 3 and 4 and plane p3. Whichever vector angle V1, V2 is greater is the vector angle. For example, in the configuration of contoured portion 26 shown in
In order to achieve satisfactory surface quality of exteriorly disposed surface 18, the vector angle is adjusted depending on the desired draw depth of contoured portion 26. Facings 14, 16 are molded from a loose mat of cellulosic fibers and a thermosetting binder, such as a urea formaldehyde, melamine formaldehyde, and/or phenol formaldehyde binder, commonly used in the manufacture of fiberboard. Preferably, facings 14, 16 are formed by a dry process, short fiber of between about 1 to 3 millimeters in length, cellulosic mat having a substantially constant basis weight or density. In addition, facings 14, 16 preferably have a substantially uniform caliper in the planar portions, with a caliper variability of about 15% or less in the contoured portions. The mat is compressed using heat and pressure. During compression of the mat, the fibers do not “flow”. Rather, the cellulosic fiber mat is stretched thereby reducing the basis weight, particularly in contoured portions 26. If the fiber mat is stretched too much, cracks and other imperfections develop on exteriorly disposed surface 18. The resulting cracked facing is not commercially acceptable.
The amount of stretch of either angled area 28 or angled area 30 may be measured by the “local stretch factor.” Typically, angled area 28 or angled area 30 has a length (length L1 and length L1′) that is greater than a horizontal dimension of a corresponding length of a planar portion, such as L2 or L2′ as shown in
As best shown in
Note that length L1 may be determined by a straight line from point 1 to point 2 if the angled area 28 (or 30) is substantially straight, as shown in
A permissible local stretch factor is inter-related to the vector angle and draw depth, as best shown in
The vector angle may be adjusted depending on a desired draw depth, so that a permissible local stretch factor is achieved. Referring to
Draw depth may also be adjusted depending on a desired vector angle. Referring again to
Thus, a vertical line on the chart shown in
For wood composite panels, such as facings 14, 16, molded to have a contoured portion 26 with a relatively deep draw depth (i.e. about ½ inch or greater), the vector angle is preferably about 35° or less, which achieves a local stretch factor of preferably about 45% or less and a total stretch factor of 25% or less. Draw depths of about ½ inch or greater are identified on the chart of
In addition to adjusting the vector angle or draw depth, angled area 28 (or 30) may include a bump, or dam 34, which extends outwardly from angled area 28 and is substantially parallel to first plane p1, as best shown in
Likewise, base 32 has a planar surface that is parallel to first plane p1 (and second plane p2), as best shown in
Total stretch factor is partially determined by local stretch factors for angled areas 28, 30, given total stretch factor includes local stretch factors of angled areas 28, 30. In addition, total stretch factor may be controlled by adjusting length F of base 32. Local stretch factor of angled areas 28, 30 is generally greater than the stretch factor for base 32, given base 32 is substantially planar relative to first plane p1. As noted above, base 32 need not be planar, and may include contoured portions. However, for most configurations of contoured portion 26, the fibers forming base 32 typically undergo less stretching compared to the fibers forming angled areas 28, 30. Thus, total stretch factor may be decreased by increasing length F of base 32, thereby decreasing the proportional contribution of L1 and L1′ to total width W. For example, if a contoured portion 26 has a total width W of about 8 inches, and length F of about 2 inches, angled areas 28, 30 extend along the remaining length (which is greater than 6 inches due to stretching). If length F of base 32 is increased, the proportion of total width W encompassed by the length L1, L1′ (or C1, C1′) of angled areas 28, 30 is decreased, assuming total width W is maintained at 8 inches. In that event, the vector angle is increased. The proportional contribution to the total stretch factor by angled areas 28, 30 may be decreased by increasing the length of base 32. The total stretch factor may be decreased by increasing length F and/or increasing total width W so that the overall proportional contribution of lengths L1, L1′ (or C1, C1′) is decreased. Preferably, total recess width W is between about 1 inch and about 8 inch, with the vector angle and draw depth and length F adjusted accordingly to achieve a satisfactory local stretch factor as set forth in
For purposes of manufacturing coreless door 10, base 32 preferably has a sufficient length F to permit interior surface portions 21 of base 32 of opposing facings 14, 16 to be securely adhered together, as best shown in
One method of forming facing 14 or 16 includes providing a mold having a lower die and an upper die. The lower die has flat portions for forming planar portions of facing 14, and at least one die cavity for forming contoured portion 26. The upper die has flat portions and a downwardly extending contoured design complementary to the mold die cavity of the lower die. A cellulosic mat is disposed between the lower and upper dies, and then compressed using heat and pressure. The resulting facing 14 (or 16) includes contoured portion 26, major planar portion 24, and panel portion 22. Contoured portion 26 extends inwardly from and relative to first surface 18 of major planar portion 24, as described above. Further, the dies are configured so that contoured portion 26 has a vector angle and a depth of draw that achieves a satisfactory local stretch factor % as set forth in
Door 10′, as best shown in
As those skilled in the art recognize, doors, such as doors 10 and 10′ are manufactured by adhesively securing the facings 14, 16 to the peripheral frame and then placing each such door into a stack. The stacks eventually contain a predetermined number of doors, and the stack is then transferred to a press. The press compresses the stack and thereby causes the facings 14, 16 to tightly engage the frame 14 while the adhesive cures. Because the inserts I1, I2 and I3 are slightly thicker than the distance between the inner surfaces 20, preferably by about 0.010 inches, and because the inserts are preferably made from corrugated paper, the inserts I1, I2 and I3 are crushed during compression in the frame. Because the inserts I1, I2 and I3 are crushed during curing of the adhesive in the press, the facings 14 and 16 do not bulge outwardly.
We have found the use of the inserts I1, I2 and I3 is beneficial in reducing any tendency of the facings 14, 16 to rattle while in use. Facings 14, 16 need not be adhesively secured together at abutting surface portions 21 as in the first embodiment because inserts I1, I2 and I3 provide sufficient structural integrity and minimize any rattling between facings 14, 16. Doors can be swung aggressively, with the result that facings 14,16 may in certain instances separate initially and then engage, with the result that a noise or rattle sound might be made if they are not secured at abutting surface portions 21 or if no inserts are provided. The compressed inserts I1, I2 and I3 essentially eliminate such door-created noises. Additionally, because the facings 14, 16 are adhesively secured to the inserts I1, I2 and I3, then some added strength is provided to the door.
While we prefer that the inserts I1, I2 and I3 be manufactured from corrugated paper and adhesively secured the facings 14, 16, other materials, such as medium density fiberboard or oriented strand board, may be used. Also, the inserts I1, I2 and I3 need not be adhesively secured and there may be one or more inserts.
While the present invention has been described in terms of a various door facing embodiments, one skilled in the art would understand that the disclosed invention is applicable for any wood composite decorative panel or wood plastic composite decorative panel.
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 can be made in construction or configuration of the present invention without departing from the scope or spirit of the invention. Thus, it is intended that the present invention cover all such medications and variations.
The present application is a continuation of Ser. No. 13/438,342, filed on Apr. 3, 2012, now U.S. Pat. No. 8,287,795, which is a continuation of Ser. No. 12/792,813, filed on Jun. 3, 2010, now U.S. Pat. No. 8,146,325, which is a continuation of Ser. No. 11/035,023, filed Jan. 14, 2005, now U.S. Pat. No. 7,765,768 which is based on provisional application Ser. No. 60/536,846, filed Jan. 16, 2004, and provisional application Ser. No. 60/536,845, also filed Jan. 16, 2004, the disclosures of which are incorporated herein by reference and to which priority is claimed.
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Number | Date | Country | |
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20130014886 A1 | Jan 2013 | US |
Number | Date | Country | |
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60536846 | Jan 2004 | US | |
60536845 | Jan 2004 | US |
Number | Date | Country | |
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Parent | 13438342 | Apr 2012 | US |
Child | 13627239 | US | |
Parent | 12792813 | Jun 2010 | US |
Child | 13438342 | US | |
Parent | 11035023 | Jan 2005 | US |
Child | 12792813 | US |