Weyerhaeuser Company Limited

Kendall H Bassett

Earl D Hasenwinkle

Ronald C Wilderman

John S Selby

Richard E Wagner

John W Kerns

Gerald N Macpherson

Alkivadis G Dimakis

The invention is an edge densified lumber product of improved strength and stiffness and the method of its manufacture. The method is based on the parallel lamination of multiple plies of wood veneer. Narrow longitudinal reinforcing strips are laid along each edge of the veneer assembly between at least some of the veneer plies. Additional spaced apart veneer strips, about twice the width of the edge strips, are laid up at preselected locations in the mid-portion of the veneer assembly. These strips in the mid-portion are preferably spaced so that the distance between their centerlines corresponds to standard lumber widths. Appropriate adhesives are used to bond the assembly. The assembly is pressed to a uniform thickness so that the areas along the narrow veneer strips are densified relative to the adjacent portions. Longitudinal saw cuts are then made along the centerlines of the interior veneer strips to separate the assembly into multiple units of lumber. Bending strength and stiffness is significantly increased by having the densified areas along each edge of the resulting lumber units.

Method of making edge densified lumber product

Engineered structural wood products particularly useful in critical applications such as joists, headers, and beams where longer lengths, greater widths, and higher and predictable stress ratings may be required and to a method for making the wood products. Most logs by nature are radially anisotropic, having wood of higher density and stiffness in their outer portion adjacent the bark than is found in the inner portion. The logs are machined to segregate the denser, stiffer outer wood. A first generally rectangular component is formed from the less dense inner wood. Second generally rectangular components are formed from the stiffer outer wood. Second components are adhesively bonded to at least one edge of the first component, more usually to opposite edges. The stiffer wood is thus specifically placed where it will contribute most effectively to the properties of the product. The product is analogous to an I-beam in which the lower density first component serves as the web and the higher density second component as the flange portion The products can be handled in use in identical fashion to solid sawn lumber. They are characterized by much less variation in their stiffness than solid sawn visually or machine graded products and can be made in a wide range of width, thickness, and length.

Method for manufacture of structural wood products

Edge densified lumber product

The invention comprises engineered structural wood products particularly useful in critical applications such as joists, headers, and beams where longer lengths, greater widths, and higher and predictable stress ratings may be required. The invention is also directed to a method for making the wood products. Most logs by nature are radially anisotropic, having wood of higher density and stiffness in their outer portion adjacent the bark than is found in the inner portion. The logs are machined to segregate the denser, stiffer outer wood. A first generally rectangular component is formed from the less dense inner wood. Second generally rectangular components are formed from the stiffer outer wood. Second components are adhesively bonded to at least one edge of the first component, more usually to opposite edges. The stiffer wood is thus specifically placed where it will contribute most effectively to the properties of the product. The product is analogous to an I-beam in which the lower density first component serves as the web and the higher density second component as the flange portion The products can be handled in use in identical fashion to solid sawn lumber. They are characterized by much less variation in their stiffness than solid sawn visually or machine graded products and can be made in a wide range of width, thickness, and length.

Engineered structural wood products

Growing community of inventors

Tacoma, WA, United States of America

Kendall H Bassett