Patent Application
20150258761
1. Field of the Invention
The present description generally relates to wooden doors designed to resist moisture and methods of manufacturing the same.
2. Description of the Related Art
Exterior doors are often used as an architectural feature in a home, business, or other building. In many applications, architects request wooden exterior doors to impart a high quality, sophisticated appearance to a structure. Wood doors, for example, can be stained to use the natural wood grain in the exterior design of a structure. The exterior doors can be of various styles such as French doors. The exterior doors can also be located in different areas of a home, for example front entry doors, patio doors, or side garage doors.
Exterior wooden doors are often assembled from various frame module components that may include left and right wood stiles, top, lock and bottom wood rails extending between the stiles, and wood mullions extending between the rails to separate the wood panels. Wood panels or glazing components can be used to fill the openings between the frame module components. These doors may also utilize engineered components that include a veneer on one or more surfaces.
Although exterior wooden doors are often architecturally desirable, architects, builders, or owners often select metal and fiberglass doors because exterior wooden doors can experience moisture damage if they are not properly treated before installation and not properly maintained thereafter. For example, exterior wooden doors can absorb moisture in the open-grain ends of the stiles at the bottom of the door, moisture can travel up the joint between the bottom rail and stile modules, and moisture can also infiltrate through the surface of the wood over time. In either situation, the moisture is eventually wicked into the joint locations.
Because moisture cannot readily escape from the joint locations, rotting can occur in the lower and upper ends of a door, but most commonly in the lower end of the door. The moisture in the wood can further cause the rails and the stiles to warp or swell, which results in the door not maintaining a proper fit within the door frame, the deterioration of the appearance of the door, or both.
In one aspect of the invention, a moisture resistant wooden door includes a number of door components joined together to form the door; and a moisture resistant overlay bonded to at least one surface of the door for inhibiting the infiltration of moisture into the one surface of the door covered by the overlay, the overlay substantially covering the one surface.
In another aspect of the invention, a method of constructing a moisture resistant wooden door includes assembling a number of door components into a door assembly; adhering a moisture resistant overlay to at least one surface of the door assembly; inserting the door assembly with the overlay into a press; applying at least a pressure to the door assembly and the overlay; and removing the door assembly from the press.
In yet another aspect of the invention, a method of constructing a moisture resistant wooden door component includes obtaining at least one assembly-ready door component; adhering a moisture resistant overlay to at least one surface of the door component; inserting the door component with the overlay into a press; applying at least a pressure to the door component and the overlay; and removing the door component from the press.
In the drawings, identical reference numbers identify similar elements or acts. The size and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements are not drawn to scale, and some of these elements are arbitrarily enlarged and positioned to improve drawing legibility. Further, the particular shapes and the elements are not intended to convey any information regarding the actual shape of the particular elements, and have been solely selected for their ease and recognition in the drawings.
The following description is generally directed toward exterior wooden doors and methods for fabricating exterior wooden doors. In all of the embodiments discussed below, a moisture resistant overlay can be adhered to a completed door assembly, or to each individual door component before assembly. The purpose of the overlay is to inhibit or resist moisture from penetrating the exterior surface of the door assembly. In some embodiments, assembling the door with moisture resistant end-caps, also referred to as performance blocks, and then applying the overlay can further augment the moisture inhibiting characteristics of an assembled door. Each of these features and variations thereof are discussed in detail below.
The description commences with a discussion of wooden door assemblies having a moisture resistant overlay and then follows with a discussion regarding methods of installing the overlay on a variety of door assemblies. The description closes with a general discussion on the various ways to assemble a wooden door. One skilled in the art, however, will understand that the invention may have additional embodiments, or that the invention may be practiced without several of the details described in the following description.
The overlay 14 is made from a material that can be primed, painted, and resists the infiltration of moisture through the thickness of the overlay 14. Overlay 14 may also be pre-primed. One type of overlay material found to have good moisture resistant characteristics is made from a phenolic resin-impregnated paper having a thickness in the range of 0.010 inches to 0.040 inches, with an average or typical thickness of 0.020 inches. The industry name for this type of overlay is Medium Density Overlay (MDO). In addition to the moisture resistant properties of the overlay 14, other attributes of the overlay 14 are that it masks imperfections in the door 10 and if pre-primed, the overlay 14 may be painted without any preparation. Moreover, the overlay 14 can be easily and cleanly machined, for instance when making the cutout in the overlay 14 to display the glazing 20. It will be understood that the overlay 14 may be a solid sheet, for example when used on a door that does not contain a glazing component.
As an alternative to the phenolic resin-impregnated paper—MDOs, the overlay 14 can be made from vinyl or laminate material comprised of melamine, phenolic plastic, polyester, or other thermosetting plastic. Overlay 14 material is typically produced in extruded sheet form, for example similar to vinyl, or in rolls. The overlay can be opaque or transparent. The overlay 14 can also be pre-coated with a chemical activated or heat activated adhesive, as this would eliminate the need to use a separate adhesive to attach the overlay 14 to the door assembly 12. Using a pre-coated overlay 14 provides the manufacturer the advantage of not having to store adhesive in inventory, which can reduce the cost of the finished product. One manufacturer of overlays 14 is a Finland based company called Dynea Overlays with a manufacturing plant in Tacoma, Wash.
Methods of Attaching Overlay Material onto Wooden Door Components
In the illustrated method, a determination is made as to whether the stile modules 16 include performance blocks 24, step 104. If performance blocks 24 are attached to the stile modules 16, then extra steps must be performed in order to insure that the overlay 14 properly bonds with the built-up door assembly 12. More particularly, if performance blocks 24 are used, the performance blocks 24 are surface treated and preheated, steps 106 and 108 respectively.
Surface treating the performance blocks 24 is done to create a more secure bond between the performance block 24 and the overlay 14. One treatment method is to sand the receiving surface 32 (
Preheating the performance blocks 24, in step 108, has been found to further enhance the bond between the performance blocks 24 and the overlay 14. One method of preheating the performance blocks 24 is to blow hot air onto the performance blocks 24 to raise the temperature of the performance blocks 24 to a point where they are hot to the touch. An adequate temperature for the performance blocks 24 prior to applying the bonding agent has been found to be in the range of 140 degrees Fahrenheit to 180 degrees Fahrenheit, with a preferred range of about 160 degrees Fahrenheit to 170 degrees Fahrenheit.
However, if the exterior surface of the stile module 16 has received a raw stock veneer component 28, then the steps to prepare the surface of the performance block 24 for bonding can be eliminated.
To attach the overlay 14 to the stile module 16 or rail module 18, a bonding agent is applied to at least one face of the respective stile module 16 or rail module 18, step 110. The receiving face 26 that receives the bonding agent can be either a veneered surface or a non-veneered surface, depending on how the component 16 or 18 was built up. Referring back to
The bonding agent may be an adhesive such as polyvinyl acetate (PVA) or some other suitable adhesive. PVA adhesive is a curing adhesive that can be applied by rollers, wheels, extruders, ball pen applicators or a spray system. The rate of development of the bond strength will depend upon ambient temperature, applied pressure, substrate type, porosity and moisture content. In step 112, the overlay 14 is placed onto the receiving surface of the component that was wetted with the bonding agent. The component parts are then placed into a press, step 114, and subjected to an elevated pressure and temperature, step 116.
In one embodiment, the pressure in the press is set within the range of about 100-200 pounds per square inch (psi), the temperature within the press is elevated to be within the range of about 200-300 degrees Fahrenheit, and the modules 16 and 18 are treated in the press for about two to four minutes. In an alternate embodiment, the pressure in the press is set within the range of about 100-200 psi, the temperature within the press is maintained at ambient or room temperature, and the modules 16 and 18 are treated in the press for about 25-35 minutes.
After the overlay 14 has been in the press for the preselected amount of time, the components are removed from the press in order to cool, step 118. Any final trimming, machining, or sanding operations, if needed, for example routing the overlay material around the edges, can then be performed, step 120. Finally, in step 122, the stile module 16 and the rail module 18 are assembled into a moisture resistant wooden door 10, which may or may not include a glazing 20. Bonding the modules 16 and 18 is accomplished by applying adhesive to the dowel holes, the sticking, and the faces of the joining surfaces of the modules 16 and 18.
The first step 202 of the illustrated method 200 involves obtaining assembly ready stile modules 16 and assembly ready rail modules 18. In step 204, the stile modules 16 and rail modules 18 are assembled into a build-up door assembly 12. In step 206, the built-up door assembly 12 is sanded to bring the outside surface within the flatness tolerance and remove any imperfections. In one embodiment, 50 grit paper can be used to initially sand the door surfaces, while 80-100 grit paper can be used to finish-sand the door surfaces.
Steps 208 through 212 are the same as the corresponding steps discussed in the previous method 100. In optional step 214, a bonding agent is applied to the receiving surface of the built-up door assembly 12. The receiving surface can be either a veneered surface or a non-veneered surface, as discussed above. The bonding agent may be an adhesive such as polyvinyl acetate (PVA) or some other suitable adhesive. Alternatively, the overlay 14 may be pre-coated with a glue line adhesive, thus making step 214 unnecessary. If the overlay 14 with the glue line is used, the exterior surface of the stile module 16 has to include a raw stock veneer component 28. In step 216, the overlay is placed onto the receiving surface of the built-up door assembly 12.
Steps 218 through 224 are substantially similar to the corresponding steps of the previous embodiment, except in the present embodiment, the door 10 is inserted into the press in step 218. The time, pressure, and temperature applications discussed in the previous embodiment are equally applicable here. In step 222, the door 10 is removed from the press to cool. Finally, in step 224, any final trimming or machining can be done to the overlay 14, the door 10, or both. For example, even if the door includes a glazing 20, the overlay 14 may be attached to the built-up door assembly 12 as a full sheet, thus covering the glazing 20. Therefore, after the door 10 is removed from the press, the overlay 14 must be trimmed to expose the glazing 20. The trimming of the overlay 14 is typically done with a router.
In another embodiment, a hot roll laminating system uses a heat application to bond the overlay to the wooden door. The overlay and door are simultaneously fed through a series of pinch rollers that apply heat and pressure to the door surface. The heat activates the adhesive on the backside of the overlay, which creates a bond to the outer surface of the door.
The stile modules 16 are the structural side supports for the door 10. The stile modules 16 are typically made from wood species such as Pine, Fir, or Hemlock, although other types of wood can be used. Additionally or alternatively, at least a portion of the stile modules 18 can be made from a composite material, such as the composite material used for the performance blocks described above, for example. Components for the stile modules 16 arrive at the door manufacturer as raw stock parts. A raw stock part is a wooden door component that has been cut to at least the approximate dimensions for assembly into a door 10. It is often the goal of the door manufacturer to receive the raw stock parts in such a configuration that no further machining is required, but due to variations in humidity, tooling, etc., it can be necessary that the raw stock parts need to be machined upon arrival at the door manufacture in order to make the raw stock parts ready for the build up process.
Once the cut blank details are joined together, the top and bottom surfaces of the built-up components are then planed to make them flat and parallel. Veneer 28 can then be adhered to at least one surface with a bonding agent such as polyvinyl acetate (PVA) or other suitable adhesive. In the illustrated embodiment, the veneer 28 is applied to only the interior surface 42 of the assembled raw stock components.
Referring back to
In order to avoid water infiltration through the end grains 44 of the stile core 16a and/or edge strips 22, one embodiment of the present invention incorporates the performance block 24 to protect the end grain 44 regions the stile module 16. Details regarding the various alternatives for performance blocks 24 are discussed below.
Referring back to
The various styles of performance blocks 24, methods of attaching the performance blocks 24, and other purposes and advantages of the performance blocks 24 are described in detail in the following U.S. patent: “WOOD DOORS AND METHODS FOR FABRICATING WOOD DOORS” U.S. Pat. No. 6,185,894 issued to Sisco et al, filed on Jan. 14, 1999.
In the illustrated embodiment of
The rail core 18a and the edge strips 22 are joined together. The top and bottom surfaces of the assembly are then planed to make them flat and parallel. The veneer 28 can then be adhered to at least one surface with a bonding agent such as (PVA) or other suitable adhesive.
As illustrated, the various raw stock components can have an end grain 44. However, unlike the stile core 16a, the end grains 44 of the respective rail core 18a and edge strips 22 are not exposed because the end grain 44 surfaces are abutted with the stile module 16 during the door assembly. However, one area of concern with respect to water infiltration into the rail module 18 is that the exposed surfaces of the rail module 18 can absorb moisture through longitudinal interstices 46 (
Referring back to
As previously mentioned, the center portion of the door 10 can be a glazing 20, which is typically a glass insert, but can be any variety of aesthetic materials that would enhance the appearance of the door and/or allow light to be transmitted therethrough. The glazing 20 is typically affixed within the door assembly 10 with a sticking and glazing bead 48 (
The descriptions provided herein where an overlay 14 is applied to a wooden door assembly, illustrate that the overlay 14 may be applied to various embodiments of a door assembly and provide numerous advantages. The overlay 14 can inhibit or prevent moisture damage, yet provide an aesthetically pleasing, smooth, door surface. In addition, application of the overlay 14 to a wooden door minimizes the amount of maintenance required, for example re-staining or re-painting.
In the above description, certain specific details are set forth in order to provide a thorough understanding of various embodiments of the invention. However, one of ordinary skill in the art will understand that the invention may be practiced without these details. The U.S. patent referred to in this specification, U.S. patent: “WOOD DOORS AND METHODS FOR FABRICATING WOOD DOORS” U.S. Pat. No. 6,185,894 issued to Sisco et al and filed on Jan. 14, 1999, is incorporated herein by reference, in its entirety.
Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
Any headings provided herein are for convenience only and do not interpret the scope or meaning of the claimed invention.
One reasonably skilled in the art will understand that particular features of the various embodiments may be combined with other embodiments to create new embodiments. These and other changes can be made to the invention in light of the above detailed description. In general, in the following claims, the terms used should not be construed to limit the invention to specific embodiments disclosed in the specification, but should be construed in accordance with the claims. Accordingly, the invention is not limited by the disclosure, but instead its scope is to be determined entirely by the following claims.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10932843 | Sep 2004 | US |
| Child | 14664634 | US |
