Edge joining of boards
Kind Code:

An improved and strengthened wide board composed of multiple edge joined narrow boards for use in commercial and residential construction is disclosed. These wide boards are typically used for purposes such as shelving, stair treads, or other purposes where they may be appropriate. The improved wide board is made by drilling or boring holes from edge to edge through the width of each narrow board, with the exception of the leading narrow board in each wide edge joined board, in a manner that accommodates screws or fasteners, which act to securely clamp or pull the boards together. These holes are step-drilled in a manner that allows the head of the screw or fastener to be recessed below the edge of the narrow board, in order to attain a smooth or flush surface between boards. The hole then steps down to a smaller diameter to accommodate the shank of the screw. A screw may then be inserted in a manner that its shank end exits the hole and “bites” into the edge of the next adjacent board. Sufficient torque may be used to tightly and securely clamp or pull the boards together. The holes so drilled are offset on alternating narrow boards in a manner that allows the screw to “bite” into solid wood, while avoiding the holes drilled into its adjacent board. When glue is applied to the board's edges, the screws act as permanent clamps. Not only do the screws serve as clamps during the setting or curing of the glue, but also they retain this clamping and securing action throughout the life of the board. The mechanical fasteners add redundancy to the glue joints, while the glue joints add redundancy to the mechanical fasteners. Such redundancy may minimize or eliminate the possibility of subsequent delamination. The improved and strengthened edge joined wide board provides an effective method of conserving valuable woods by using narrow boards that may be obtained from renewable trees, rather than solid wide boards from old-growth nonrenewable trees.

Spivey, Fenner N. (Louisburg, NC, US)
Application Number:
Publication Date:
Filing Date:
Primary Class:
Other Classes:
52/582.2, 52/585.1, 52/586.1, 52/396.05
International Classes:
B27M3/00; E04C2/292; E04F11/108; E04F13/10; E04F15/04; (IPC1-7): E04B1/68; E04F15/14
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Primary Examiner:
Attorney, Agent or Firm:
Fenner N. Spivey (Louisburg, NC, US)

What is claimed is:

1. An improved method of edge joining wood boards for commercial and residential use said improvements comprising: the drilling or machining of holes edge-to-edge through the lateral axis of the board or boards; and the insertion of screws or other fasteners through the holes so drilled in such a manner that the screws or fasteners enter the next adjacent board and pulls or clamps the boards together.

2. The improved edge joined boards of claim 1, wherein the screws act as permanent clamps or holding devices.

3. The improved edge joined boards of claim 1, wherein the screws add permanent redundancy to edge-glued joints.

4. The improved edge joined boards of claim 1, wherein the glue joints add redundancy to the mechanical clamping and/or holding action of the screws.

5. The improved edge joined boards of claim 1, wherein the requirement for external clamping devices is negated.

6. The improved edge joined boards of claim 1, wherein subsequent delamination is reduced or eliminated.



[0001] It requires a very large tree to produce solid wood boards with sufficient width for such uses as shelving, stair treads, etc. These large trees are generally considered to be a nonrenewable resource due to their age and the very long time periods that are required for growth to a size that will render boards of such required width.

[0002] Through appropriate reforestation, the use of younger and smaller trees has become a generally recognized renewable resource. These smaller trees are now finding extensive use in the manufacture of engineered woods; such as oriented strand board (OSB), fiber board (MDF), particleboard, etc.

[0003] When the logs from these smaller trees are processed in sawmills, the resulting boards lack the width required for such shelving, stair treads or other purposes.

[0004] Therefore, the edge gluing of narrow boards to obtain the desired width has become an attractive, and generally accepted, alternative when wide boards of natural woods are required. Such narrow boards may be obtained from the smaller, younger growth trees that qualify as a renewable resource. This edge gluing of boards is now a fairly common practice for many applications.

[0005] Varying techniques and types of adhesives are used for edge gluing operations. These include cold clamping, hot melts, radio frequency gluing, etc. However, each technique or type has two common procedures.

[0006] First, each technique uses a method of clamping the boards edge-to-edge. These clamps hold the boards tightly together, edge-to-edge, while the glue sets or cures. Methods commonly used for clamping range from simple bar clamps to more sophisticated pneumatic or hydraulic clamping devices. However, once the glue that holds the edge-glued wide board together has been cured, the clamping forces are released, the board is removed from the clamps, and the reinforcing action of the clamps no longer exists. The boards so joined are now free to adjust to their surrounding environment of temperature and humidity. Warping and/or delamination is sometimes the result of the edge-glued board's adjustment to its environment.

[0007] Second, each of these described techniques is completely dependent on the integrity of the glue joint alone. There is nothing other than glue to securely hold the boards together as a single unit following the clamping and gluing operations, nor to prevent subsequent delamination.

[0008] This Inventor has observed numerous instances of delamination of edge-glued boards. Such delamination may occur months or even years after the boards have been edge-glued together. This subsequent delamination is thought to result from changes in the moisture content of the environment in which the board is installed.

[0009] Natural woods will expand with increases in moisture content, and they will contract with decreases in moisture content. Bearing in mind that the subject wide boards are formed from a multiple of more narrow boards, each of the narrow boards will tend to react independently to such increases or decreases in moisture content.

[0010] Therefore, if the individual boards in this wide board respond is a symmetrical manner; the board will likely retain its structural integrity. However, if an individual board's grain structure, or other characteristic, should create an asymmetrical response to the other boards, very large internal pressures are created on the bond that holds the boards together. This pressure may, at times, be sufficient to destroy this bond, resulting in delamination.


[0011] The present invention has been developed to provide a solution that offers additional protection against such delamination along with an improved method of clamping that continues its clamping action throughout the life of the wide board. In lieu of removing the finished or cured wide board from clamps and rendering it free to adjust to its environment, this present Invention utilizes an improved clamping technique in which the wide board is not removed from its internal clamps. This improved technique negates the need for the other previously described external clamping devices.

[0012] THIS PRESENT INVENTION utilizes mechanical fasteners, such as simple wood screws, to securely hold the boards edge to edge.

[0013] First, each narrow board is step-drilled or bored from edge to edge. The drill enters one edge and goes through the board to exit the other edge. The face side and back side of the board is unchanged. The step drilling accomplishes holes in the leading edge sufficient in size for the head of the screws to recess into the wood to the point where a smaller hole accommodates the shank of the screws.

[0014] Screws or other fasteners are then inserted in a manner that the screws enter the edge of the adjacent board to a depth sufficient to pull the boards tightly and securely together. The screws now act as permanent clamps.

[0015] When glue is applied to the board's edges prior to its being clamped by this screw action, the glue joint is clamped by the screws during the setting or curing process.

[0016] Following this setting or curing of the glue joints, the screws simply remain in place to act as permanent clamps throughout the life of the wide board so created.

[0017] The result is an edge-glued wide board that is not singly dependent upon either the glue joint or the mechanical fasteners. Each reinforces the other to protect structural integrity.

[0018] When multiple boards are joined edge to edge to produce wide boards, the holes that are step drilled or bored into each alternating board must be offset sufficiently to allow the screws to “bite” into the edge of its preceding board; otherwise, it would encounter the hole in such preceding board and be ineffective in holding. This is more fully demonstrated in the attached drawings.

[0019] When self-tapping screws are used, it is generally unnecessary to drill or bore into the leading or front board in the assembly, as will be seen.

[0020] It is therefore, an object of this present Invention to provide a simplified method of clamping narrow boards together to form wide boards.

[0021] It is another object of this present Invention to provide improved stability and structural integrity in the form and shape of wide boards for commercial and residential construction.

[0022] Another object of this present Invention is to provide the additional security of combining edge-gluing of boards with mechanical fasteners to prevent subsequent delamination.

[0023] Another object of this present Invention is to promote use of renewable resources through the use of narrow boards in lieu of non-renewable resources when solid wide boards are used.

[0024] An additional object of this present Invention is to fully preserve visual and aesthetic properties of reinforced wide boards for further use and finishing in its subsequent use.


[0025] FIG. 1 is a face or top perspective of a narrow board that has been step-drilled from edge to edge.

[0026] FIG. 2 is a face view of the adjacent board showing offsets in step drilling to allow screws or fasteners to avoid adjacent holes, and to “bite” into solid wood.

[0027] FIG. 3 is the leading board of an assembly of multiple boards. No drilling is required in this leading board when self-tapping screws are used as clamps.

[0028] FIG. 4 is a top or face view of three boards showing the method whereby the screws or fasteners act to securely clamp and hold the boards together to form a wide board.


[0029] With further reference to the drawings, there is shown therein the top or face side, or flat surface of a wood board in accordance with the present Invention, indicated generally on Page 8 and illustrated in FIG. 1.

[0030] This FIG. 1 shows holes that have been step-drilled or bored beginning in one edge of the board and exiting the opposite edge of the board. Shown at (A) is a hole with sufficient diameter to allow the recessing of the head of a screw or fastener well below the surface of the board's edge. This recessing allows the board's edge to remain smooth and flush with any board that may be joined adjacent thereto.

[0031] Shown at (B) in this FIG. 1 is a continuing hole that has been stepped down in diameter to accommodate the shank of the screw or fastener that acts to securely clamp and hold the board together with the next adjacent board. The beginning point of this smaller hole also acts as the holding point or anchor for the recessed head of the screw or fastener. As the screw “bites” into the adjacent board, this anchor point permits sufficient torque to be applied to pull or clamp the boards securely with the use of these mechanical fasteners.

[0032] Shown on Page 8 and illustrated as FIG. 2 is an illustration of the method by which each alternating board may have the step-drilled holes offset in a manner that prevents the screws from entering an adjacent board and entering the holes drilled into such adjacent board. By this alternating offset, the screw or fastener is enabled to “bite” into the solid wood of its adjacent board.

[0033] Shown on Page 8 and illustrated as FIG. 3 is the face or top of the leading board that is encountered in the assembly of multiple narrow boards to create a wide board. When self-tapping screws are used, there is no requirement for any drilling or boring to be performed on this leading board. It becomes securely clamped and held together by screws from the next adjacent board.

[0034] Shown of Page 9 and illustrated as FIG. 4 is an assembly of three boards to illustrate how the boards are clamped by the alternating holes. Shown at (A) in this FIG. 4 is the hole drilled to accommodate the recessing of the screw head. Shown at (B) in this FIG. 4 is the head of the screw or fastener, which anchors at the bottom of the hole depicted in (A). Then, shown at (C) in this FIG. 4 is the shank of the screw where it “bites” into the edge of the next adjacent board. This “bite” permits sufficient torque to be used to very tightly pull the board together and secure them with these mechanical fasteners.

[0035] As shown in this FIG. 4, when glue is applied to the board's edges prior to inserting and tightening the screws, the screws act as clamps during the setting or curing process for the glue. They then remain permanently in the boards to provide the additional security of both edge-glued boards plus permanent clamps or mechanical fasteners.

[0036] From the above it may be seen that this present Invention provides a practical and effective method of enhancing the structural integrity of edge-glued wide boards.

[0037] The clamping used for edge-gluing of boards is not removed following the setting of the glue, as was done in the prior art. In this present Invention, the internal clamping remains with the wide boards throughout their useful life.

[0038] In the event of subsequent glue joint failure, the screws offer redundancy.

[0039] In the event of subsequent mechanical failure, the edge-glued joints offer redundancy. The present Invention may, of course, be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of such Invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.