This invention relates to doors having internal blocking components that reduce or eliminate telegraphing of the outer surface of the door facings. In particular, this invention relates to steel-edge steel doors that have internal solid wood blocks that have one or more integral cantilever beams formed into the blocks to interact with the adjoined oppositely arranged door facings in order to eliminate visually apparent door telegraphing.
Lightweight construction panels, such as used in doors, are typically constructed of a frame forming an outer perimeter, door facings (sometimes called door skins) attached to opposing sides of the frame, and a lightweight core filling the space between the facings and the frame. Blocking components, typically made of wood, are incorporated at selected locations about the interior of the door, where additional structural support is desired, e.g. such as to provide structures to fasten or connect other components to the door or the entry system. The core is formed from a material that typically has different physical properties (e.g. tensile strength, thermal coefficient of expansion, etc.) than the block components, with the result that the door facings may deform at the intersection of the blocking components and the core. The deformation is believed to be due to differential thermal expansion between the core material and the material of the block components, or differential shrinkage occurring during processing of the door. Deformation may also be caused by loadings on the door in the area over the more compliant core, causing the core to compress more than the rigid blocking components. Visually noticeable deformation of the surface of a door facing, at the intersection of the core and blocking components below the surface, is referred to as telegraphing. Should the door facings be made of steel, then the deformation will usually be permanent. Telegraphing may cause a consumer to believe there is a defect in the door, thus reducing salability of the door or decreasing its aesthetic value.
While efforts have been made to minimize telegraphing, those efforts have not been completely successful. Therefore, there remains a need for lightweight construction panels, such as doors, that eliminate or reduce telegraphing.
A first aspect of the present invention relates to doors having blocking components that have at least two notches, such as kerfs, formed therein to form cantilever beams that reduce or eliminate telegraphing. The door contains a pair of opposed door facings secured to opposite sides of a peripheral door frame. A core and blocking components fill the internal cavity inside the frame and between the door facings. The blocking components contain notches, such as kerfs, formed in a surface thereof which extend approximately parallel to the major plane of the facings. In a preferred embodiment, the notches extend a substantial portion of the length (or width) of the blocks in parallel, and may be of differing or the same depth.
A further aspect of the present invention relates to steel-edge steel doors having core and a stile block in the internal cavity inside the frame and between the door facings. The stile block contains parallel notches, such as kerfs, extending through the width of the stile block and parallel to the major surface of the facings.
Other aspects of the invention, including methods, processes, systems, and the like which constitute part of the invention, will become more apparent upon reading the following detailed description of the exemplary embodiments.
The accompanying drawings are incorporated in and constitute a part of the specification. The drawings, together with the general description given above and the detailed description of the exemplary embodiments and methods given below, serve to explain the principles of the invention. In the drawings;
Reference will now be made in detail to exemplary embodiments and methods of the invention. It should be noted, however, that the invention in its broader aspects is not necessarily limited to the specific details, representative materials and methods, and illustrative examples shown and described in connection with the exemplary embodiments and methods. Like reference characters refer to like parts throughout the drawings.
A door 100, as best shown in
In areas where reinforcement is needed, one or more blocking components 112 may be placed in the core. Those reinforcement areas may be, but are not limited to, areas for mounting locks and handles to the door (lock block 112a) and for mounting hinges to the door (hinge block 112b). The blocking components 112 may be made of wood or polymeric materials, and preferably are solid wood.
Those skilled in the art recognize that the door facings 102 may be made from wood composite, polymer reinforced composite, such as fiber glass, and metals, such as steel. Telegraphing is a particular problem where the door facings 102 are made of steel. Likewise, the stiles 106 and the rails 108 are normally made of solid wood, although other materials may be used. The door facings 102 conventionally are secured to the frame 104 by adhesive, such as polyvinyl acetate (PVA), hot melt adhesive, or even from the foam frequently used for the core 110. Where the door facings 102 are made of steel, the frame 104 may require only rails 108.
A blocking component 112 is shown in
One or more of the blocking components 112 may be modified along the surfaces 118, 120, 122, and 124. Two or more notches 126, such as kerfs formed by saws, are formed into each blocking component 112 and extend along the surfaces 118, 120, 122, and 124 in a direction parallel to the plane of the door facings 102. As best shown in
Although
Telegraphing has been a particular problem at the end of the stile block that is installed along the latch stile of steel-edge steel doors to provide additional structural support. Because the wood stile blocks are more rigid (higher modulus of elasticity) than the polyurethane foam core, a permanent deformation may be formed in the steel face of doors directly over the intersection of the stile block and foam when a load is placed on the face of the door. For example, such permanent deformation can occur on the doors toward the bottom of a pallet of doors which has multiple of doors stacked thereon.
While not wishing to be bound by any theory, it was found that cutting kerfs or notches in the stile block parallel to the door facings 102, and at an appropriate spacing from the door facings 102, creates a deformable cantilever beam near the edge of the stile block. The stile block can as a result deform in a gradual, controlled manner so the deformations of the associated door facings 102 are much less visible. The notches 126, such as leafs, formed by the saw resulted in a door construction that reduced telegraphing to an acceptable level or even eliminated it completely.
One's eye picks up a more abrupt change in light scattering angle associated with greater rate of change in slope of the door facing surface. By reducing the rate of slope change at the edge of the door facing near the stile block, the door facing can deform to a similar depression depth but not be as detectable visibly because the change in surface angle is more gradual. The gradual curvature of a “cantilever beam” is an efficient, effective, and novel way to address this problem.
In a preferred embodiment, door 100i is a steel-edge steel door, as best shown in
The door 100i contains parallel rails 108i at the top and bottom of the door. The door 100i contains steel edges 400 and 402 that are sufficiently strong to support the door 100i without requiring conventional wood stiles. The steel edges 400 and 402 are formed from a perpendicular fold in their respective steel door facings 102i and 102j. For example, the hinge side steel edge 400 is formed by bending one edge of the outside door facing 102i approximately 90°; and the lock side steel edge 402 is from by bending one edge of the inside door facing 102j approximately 90°. Of course, the reverse, where the hinge side steel edge 400 is formed from the inside door facing 102j and the lock side steel edge 402 is formed from the outside door facing 102i, is also contemplated by the present invention. Thus, each of the door facings 102i and 102j contains a major surface and an edge extending approximately perpendicular from the major surface.
The door 100i also includes a lock block 112i for mounting of the door lock and/or the door handle. The lock block 112i may include one or more holes to facilitate such hardware mounting. When assembled, the holes in the lock block 112i are placed in registry with corresponding holes in the facings 102i and 102j. A solid wood stile block 404 is placed adjacent to the lock block 112i and between the lock block 112i and the lock side edge 402. The lock surface 122i of the stile block 404 is preferably in contact with the lock side edge 402 and overlaps a portion of the length of the lock side edge 402 (the stile block 404 is shorter than the lock side edge 402); and the hinge side surface 124i (opposing the lock surface 122i and facing the hinge side of the door 100i) is preferably in contact with the lock block 112i. The stile block 404 also contains surfaces 114i and 116i, which are in contact with the opposed major surfaces of the facings 102i and 102j (see
The door 100i may also include other blocking components 112j, e.g. for attachment of door closure hardware, or steel reinforcements 406 for hinge mounting. The reinforcements 406 may be metallic plates attached to the inside of the hinge side edge 400 for attachment of hinges for mounting the door 100i.
Thermal barriers 408 are preferably used to prevent contact, and thus, thermal conduction between the door facings 102i and 102j. The thermal barriers 408 are preferably polymeric materials having low thermal conductivity and placed on the edges 400 and 402 to prevent their direct contact with the opposing door facing 102j and 102i, respectively. Thus, a first thermal barrier 408 is placed between the hinge side edge 400 and the door facing 102j to prevent their physical contact; and a second first thermal barrier 408 is placed between the lock side edge 402 and the door facing 102i to prevent their physical contact (see
As best illustrated in
As best shown in
Preferably, each of the notches 126i has a width wi of about 0.094 in. to about 0.156 in., preferably about 0.125 in., and a depth di of about 4 in. to about 6 in., preferably about 5.5 in. In certain embodiments, the notches 126i may have the same or different depths (see
As best shown in
As best shown in
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Although certain presently preferred embodiments of the invention have been specifically described herein, it will be apparent to those skilled in the art to which the invention pertains that variations and modifications of the various embodiments shown and described herein may be made without departing from the spirit and scope of the invention. Accordingly, it is intended that the invention be limited only to the extent required by any appended claims and the applicable rules of law.
This application is related to application No. 62/748,116, filed Oct. 19, 2018, the disclosure of which is incorporated herein by reference and to which priority is claimed.
Number | Date | Country | |
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62748116 | Oct 2018 | US |