Interlocking system for waney lumber
A hollow core composite wood product comprising four elongated pieces of lumber, at least two of which are waney pieces of lumber. The elongated pieces are profiled to remove both longitudinally extending edges on one side thereof such that each of said elongated pieces has longitudinally extending indented portions on one side. The indented portions are shaped so as to be complementary to and engageable with the indented portions of adjacent pieces. The pieces are positioned adjacent to one another such that the indented portions are engaged with one another and the pieces together define a longitudinally extending cavity in the center of the hollow core composite wood product. The indented portions of said first pieces are bonded to the indented portions of said second pieces by an adhesive. The indented portions are shaped such that adjacent pieces fit into a self-aligning, interlocking engagement, preventing lateral movement of the pieces relative to one another. This enables the hollow core composite product to be pressed in a conventional one-dimensional press.
The present invention relates to composite wood products, such as beams, headers, corbels and posts, manufactured from waney lumber.
BACKGROUNDThe term “waney lumber” refers to boards or pieces of wood that, instead of being cut square, show the original curve of the log from which they are cut. Due to the curvature and irregular shape of waney lumber it is difficult to use in the manufacture of wood products As a result, waney lumber is relatively cheap and underutilized. Products and processes using waney lumber generally result in little added value and a great deal of waste.
Many composite lumber products are made by simply gluing pieces of lumber together. For example, elongated wood pieces can be glued and pressed together to make laminate beams, usually of rectangular cross section. Placing one wood piece over another constitutes a lamination process, which results in a maximum of wood fiber per cross-sectional area and hence a maximum cost per unit of beam. Such a lamination process also requires the use of lumber having rectangular cross-section, which means that waney lumber generally cannot be utilized. If such products can be made from waney lumber at all, a great deal of material waste results because the waney lumber must first be squared.
There exist in the art methods for making hollow core composite lumber products which use less wood fiber per cross-sectional area, however, the cost savings is generally offset by the increased cost and complexity of the manufacturing process. For example, the manufacture of some composite products, such as disclosed by International Patent application WO 90/010092 for a WOODEN STRUCTURE, AND A ROLLER PRESS FOR PRODUCING THE STRUCTURE may require the use of a two-dimensional press. The use of a one-dimensional press and guide mechanism, or the two-dimensional press, significantly increases the capital cost as well as complexity and cost of the manufacturing process when compared to one-dimensional pressing processes. The capital costs and press-line complexity for one-dimensional pressing processes are generally far lower.
Accordingly, the objects of the present invention are to provide means for making composite wood products from waney lumber, for producing such products with a conventional one-dimensional press with no guide, and for minimizing the waste of waney lumber.
SUMMARY OF THE INVENTIONA hollow core composite wood product comprising two first elongated pieces of lumber and two second elongated pieces of lumber. The first elongated pieces of lumber are preferably waney lumber. The second elongated pieces may be waney lumber or other types of lumber. Each one of the first and second pieces is profiled such that both of the longitudinally extending edges on one side thereof are removed such that each of said first and second pieces has longitudinally extending indented portions on one side. The indented portions of the first pieces are shaped so as to be complementary to and engageable with the indented portions of the second pieces. The first and second pieces are positioned adjacent to one another such that each of the indented portions of the first pieces is engaged with one of the indented portions of the second pieces and the first sides of said first and second pieces together define a longitudinally extending cavity in the center of the hollow core composite wood product.
The indented portions of said first pieces are bonded to the indented portions of said second pieces by an adhesive.
The indented portions of the elongated pieces of lumber are shaped such that adjacent pieces fit into a self-aligning, interlocking engagement to form a hollow-core composite product, such as a beam, post or header. The engagement of the indented portions of the first pieces with the indented portions of the second pieces prevents lateral movement of the first and second pieces relative to one another. In other words, movement of the first and second pieces relative to one another in a direction along an axis substantially perpendicular to a longitudinally extending axis of the hollow core composite product and substantially parallel to the second sides of the first pieces is prevented when force is applied to the second sides of the first pieces in a direction substantially perpendicular to the second sides of the first pieces and toward a center of the hollow core composite wood product. This enables the hollow core composite product to be pressed in a one-dimensional press having no guide or pressing mechanism in a second dimension. A conventional one-dimensional press is proven technology requiring less capital and a lower level of complexity, thereby reducing the overall manufacturing cost of the composite products. At the same time it permits the fabrication of sophisticated glue-up patterns all in one gluing step—e.g. compression and tension members (e.g. high rated MSR lumber or LVL (laminated veneer lumber)) can be added for higher strength.
The profiling of the elongated pieces of lumber not only provides an advantage in the sense that the hollow core composite product can be made using a one-dimensional press, but also makes it possible to utilize waney lumber. Waney lumber is difficult if not impossible to incorporate into composite wood products due to its curved and irregular shape. However, by profiling the waney lumber to create indented portions a uniform, interlocking and self-aligning interface is achieved between adjacent pieces of lumber in the composite product while maximizing utilization of the waney lumber. In addition, the waney lumber can be profiled so as to maximize utilization of waney lumber fiber.
The present invention also contemplates a method for manufacturing hollow core composite wood products. The first step in the method is to provide two first elongated pieces of lumber and two second elongated pieces of lumber. The providing step may entail sawing logs into lumber, kiln drying, finger-jointing and planing said first and second pieces. The first and second pieces are then profiled such that first and second longitudinally extending edges on one side thereof are removed such that each of said first and second pieces has indented portions extending longitudinally along that side. Each of the indented portions of the first pieces is shaped so as to be complementary to and engageable with one of the indented portions of said second pieces. Engagement of the indented portions of the first and second pieces prevents lateral movement of the first and second pieces relative to one another.
An adhesive is then applied to the indented portions and the first and second pieces are positioned such that each of the indented portions of first pieces is engaged with one of the indented portions of the second pieces, such that a longitudinally extending cavity in a center of said hollow core composite wood product is defined by the first and second pieces. A force is then applied to the outer surfaces of the first pieces. The force is applied to the outer surface of the first pieces (i.e. the side opposite the profiled side) in a direction toward the center of the hollow core composite wood product. The force can be applied by a one-dimensional press.
The present invention provides several advantages over the prior art. The first advantage is that the invention makes use of low cost raw material, namely waney lumber. Waney lumber is the low cost since sawmillers typically process it into chips for paper production.
The present invention can also be used to achieve higher recovery from purchased lumber. The hollow core composite products can be made of lower grade or waney lumber and square edge lumber.
The present invention also enables construction of a product with the least amount of lumber necessary to meet required strength requirements. Overall a 10 to 45% fiber utilization benefit can be expected with the present hollow core composite products depending on the size of post, beam or header being manufactured. This is significant given the fact that fiber is the most important cost factor. The volume of adhesive consumed is also lower than with other engineered wood products as there are less glue lines in the products. Given the high cost of adhesives, this helps to keep costs low.
In addition to minimizing the amount of fiber used, the hollow core construction of the present invention results in a product, which is lighter to work with, thereby making it easier to handle on the job site without the use of cranes and other lifting equipment.
In comparison to conventional engineered wood products, which are susceptible to swelling when exposed to rain and moisture, the hollow core composite products of the present invention are resistant to swelling.
Finally, the lengths of waney and square-edged lumber used to construct the hollow core composite products of the present invention may be finger-jointed to achieve any desired length. Therefore the finished hollow core composite products are available in long lengths to allow customers to chop for builder specific requirements.
BRIEF DESCRIPTION OF THE DRAWINGSFurther features and advantages will be apparent from the following Detailed Description of the Invention, given by way of example, of a preferred embodiment taken in conjunction with the accompanying drawings, wherein:
Although
In the preferred embodiment waney lumber is profiled to produce longitudinally extending indented portions of said elongated profiled pieces of lumber. However, it will be obvious to those skilled in the art that a conventional square-edged piece of lumber (e.g. a 2×4) may also be profiled by removing both longitudinally extending edges on one side of the piece of lumber.
Referring to
Referring to
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Referring to
The present invention contemplates further structures and products, such as the U-shaped beam or corbel 120 of
After finger jointing 200, 210, the lumber is profiled to provide an indented portion having either a protrusion or groove, (see
The profiled lumber is then laid up 240 and glued together to form a composite post, beam/header or other product. This step involves the application of adhesive in the interfaces 85 between the elongated profiled pieces of lumber 10, 15 (see
It is obvious that one can bypass the finger-jointing step if lumber of sufficient length and quality is available.
Accordingly, while this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to this description. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as fall within the true scope of the invention.
Claims
1. A hollow core composite wood product comprising:
- a) two first elongated pieces of waney lumber, wherein each of said first pieces is profiled such that first and second longitudinally extending edges of a first side thereof have been removed such that each of said first pieces has indented portions extending longitudinally along said first side, said first elongated pieces of lumber additionally having a second side opposite said first side;
- b) two second elongated pieces of lumber, wherein each of said second pieces is profiled such that first and second longitudinally extending edges of a first side thereof have been removed such that each of said second pieces has indented portions extending longitudinally along said first side, said second elongated pieces of lumber additionally having a second side opposite said first side;
- wherein each of said indented portions of said first pieces is shaped so as to be complementary to and engageable with one of said indented portions of said second pieces;
- wherein said first and second pieces are positioned adjacent to one another such that each of said indented portions of said first pieces is engaged with one of said indented portions of said second pieces, such that said first sides of said first and second pieces together define a longitudinally extending cavity in a center of said hollow core composite wood product, and such that said second sides of said first and second pieces together define an outside surface of said hollow core composite product;
- wherein engagement of said indented portions of said first pieces with said indented portions of said second pieces prevents lateral movement of said first and second pieces relative to one another when force is applied to said second sides of said first pieces in a direction substantially perpendicular to said second sides of said first pieces and toward a center of said hollow core composite wood product; and
- wherein said indented portions of said first pieces are bonded to said indented portions of said second pieces by an adhesive.
2. The hollow core composite wood product of claim 1, wherein said first pieces are made from waney lumber and wherein said first and second edges thereof are waney edges.
3. The hollow core composite wood product of claim 1, wherein a width of said second sides of said first pieces is substantially equal to that of said hollow core composite wood product.
4. The hollow core composite wood product of claim 1, wherein said indented portions of said first pieces each have a longitudinally extending protrusion and said indented portions of said second pieces each have a longitudinally extending groove and wherein said groove is operative to receive said protrusion.
5. The hollow core composite wood product of claim 1, wherein said hollow core composite wood product has a square or substantially rectangular cross-section.
6. The hollow core composite wood product of claim 1, wherein at least one of said first and second pieces is finger jointed.
7. The hollow core composite wood product of claim 1, wherein said hollow core composite wood product is cut in four by cutting each of said first and second pieces longitudinally in two to provide four L-shaped corner products.
8. The hollow core composite wood product of claim 1, wherein said hollow core composite wood product is cut in two by cutting each of said first pieces longitudinally in two to provide two corbels.
9. A method for making a hollow core composite wood product, comprising:
- (a) providing two first elongated pieces of lumber, each of said pieces having a first side and second side opposite said first side;
- (b) providing two second elongated pieces of lumber, each of said pieces having a first side and second side opposite said first side;
- (c) profiling each of said first pieces such that first and second longitudinally extending edges of a first side thereof are removed such that each of said first pieces has indented portions extending longitudinally along said first side;
- (d) profiling each of said second pieces such that first and second longitudinally extending edges of a first side thereof are removed such that each of said second pieces has indented portions extending longitudinally along said first side;
- (e) applying an adhesive to said indented portions of said first and second pieces;
- (f) positioning said first and second pieces such that each of said indented portions of first pieces is engaged with one of said indented portions of said second pieces, such that said first sides of said first and second pieces together define a longitudinally extending cavity in a center of said hollow core composite wood product, and such that said second sides of said first and second pieces define an outer surface of said hollow core composite product;
- (g) applying a force to each of said second sides of said first pieces, said force being applied in a direction substantially perpendicular to said second sides of said first pieces and toward a center of said hollow core composite wood product;
- wherein each of said indented portions of said first pieces is shaped so as to be complementary to and engageable with one of said indented portions of said second pieces;
- wherein said engagement of said indented portions of said first pieces with said indented portions of said second pieces prevents lateral movement of said first and second pieces relative to one another when said force is applied to said second sides of said first pieces.
10. The method of claim 9, wherein said first pieces are made from waney lumber and wherein said first and second edges thereof are waney edges.
11. The method of claim 9, wherein said second pieces are made from waney lumber and wherein said first and second edges thereof are waney edges.
12. The method of claim 9, wherein a width of said second sides of said first pieces is substantially equal to that of said hollow core composite wood product.
13. The method of claim 9, wherein said indented portions of said first pieces each have a longitudinally extending protrusion and said indented portions of said second pieces each have a longitudinally extending groove and wherein said groove is operative to receive said protrusion.
14. The method of claim 9, wherein said hollow core composite wood product has a substantially square or rectangular cross-section.
15. The method of claim 9, wherein said first and second pieces are finger jointed.
16. The method of claim 9, wherein said providing steps include sawing logs into lumber, kiln drying, finger-jointing and planing said first and second pieces.
17. The method of claim 9, wherein said force is applied by a one-dimensional press.
18. The method of claim 9, further comprising the following step: after applying said force, cutting each of said first and second pieces longitudinally in two to provide four L-shaped corner products.
19. The method of claim 9, further comprising the following step: after applying said force, cutting each of said first pieces longitudinally in two to provide two corbels.
Type: Application
Filed: Sep 9, 2004
Publication Date: Mar 9, 2006
Inventor: Michael Holzhey (Kelowna)
Application Number: 10/936,547
International Classification: E04C 3/30 (20060101);