High strength composite wood veneer articles

A composite wood veneer article having a lower layer of wood veneer having a grain orientation generally in a first direction and an upper layer of wood veneer having a grain orientation generally in the first direction. At least two layers of wood veneer are interposed between the upper and lower layers. At least one of the interposed layers has a grain orientation offset from the first direction by about 10.degree. to 25.degree., preferably about 15.degree. to 20.degree.. Adjacent layers of the wood veneer are adhesively bonded in generally surface to surface relationship to each other. In one embodiment, both interposed layers have grain orientations offset from the first direction by about 10.degree. to 25.degree.. The interposed offset layers may be offset on opposite sides of the first direction. In another embodiment, the article may have three interposed layers with one of the three having a grain orientation generally in the first direction. In another embodiment, four interposed layers may be provided, and all four interposed layers may be offset at an angle of about 10.degree. to 25.degree.. Adjacent interposed offset layers are preferably offset on opposite sides of the first direction.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates generally to composite wood veneer articles having 
high strength and adapted for severe working without destroying the 
aesthetically pleasing appearance. More specifically, the invention is 
adapted to such a composite wood veneer article wherein specific grain 
orientations are so provided as to accomplish these objectives. 
2. Description of the Prior Art 
It has been known in situations where improved strength over that provided 
by solid lumber is required to provide laminated construction wherein 
alternate layers have grain orientations oriented generally 
perpendicularly with respect to each other in order to provide increased 
strength. Conventional plywood is an example of such a laminated 
construction. U.S. Pat. No. 2,578,781 discloses the use of alternate 
layers having grains oriented perpendicularly to each other. The plywood 
units are subsequently formed into tubular articles. Unfortunately, in 
producing such plywood, strength is increased at a sacrifice of machine 
workability. Plywood, when carved or scrolled, tends to disintegrate and 
become unsightly, particularly about the edges. As a result, the 
beneficial improved strength characteristics of plywood can be employed 
only in certain end use environments wherein carving or scrolling is not 
required or unsightly appearance is not objectionable. In some instances, 
a compromise is effected by performing additional finishing operations 
upon the unsightly plywood edge in order to attempt to improve its 
appearance. Such additional finishing involves increased cost and does not 
generally produce a completely acceptable, aesthetically pleasing 
appearance. 
U.S. Pat. No. 2,291,426 discloses a package wherein alternate plies have 
grains oriented generally perpendicularly with respect to each other. U.S. 
Pat. No. 1,625,280 relates to a wooden container and discloses 
multiple-layer, adhesively bonded constructions having veneer layers with 
grains oriented perpendicular to each other as well as at intermediate 
positions. 
A further problem with conventional lumber is its susceptibility to 
undesired chipping and cracking. U.S. Pat. No. 3,908,725 discloses a 
suggested approach to increasing the modulus of elasticity and modulus of 
rupture in conventional lumber. This patent discloses severing of lumber 
into plies of veneer of about 1/4 inch thickness. Three plies of veneer 
are then adhesively bonded with their grains aligned. The three-ply 
composite members are then laminated with staggered butt joints so as to 
produce a piece of laminated lumber one and one-half inch thick or greater 
multiples thereof. The structure remains, however, merely a reconstructed 
piece of lumber wherein properties are said to be improved as a result of 
the multiple laminating and seaming techniques. All grains remain 
substantially parallel to the longitudinal direction, thereby, in effect, 
reconstructing the original log grain arrangement. 
It has also been known to provide wood layers in combination with plastic 
materials in order to increase strength. U.S. Pat. No. 3,437,547 discloses 
a balsa wood assembly having an interposed layer of a polyester. 
Similarly, U.S. Pat. No. 1,628,886 discloses multiple layer wood 
construction provided with interposed material such as a pure phenolic 
condensation product. The wood may be oriented with the grains at 
differing positions, and high pressure is applied in such fashion that the 
wood becomes impregnated with the phenolic condensation product, and the 
wood fibers are compressed, thereby producing unitary, integral mass 
consisting of compressed wood fibers and penetrated phenolic condensation 
product. This is to be distinquished from constructions wherein distinct 
wood veneer layers would remain essentially intact and are merely 
adhesively bonded to each other. 
In U.S. Pat. No. 3,055,065 there is disclosed flexible flooring made of 
hardwood veneer. It is contemplated that the flooring will be secured to 
an underlying rigid material which will provide the desired reinforcement, 
strength and floor rigidity. The flooring may take the form of a single, 
flexible ply or a two-layer ply having grain orientation offset by a 
relatively small amount. 
U.S. Pat. No. 2,334,619 discloses a tubular wound multiple veneer article 
fabricated by winding, as by spiral winding, with or without cross 
winding. 
There remains, therefore, a need for a wood article having increased 
strength and resistance to chipping and cracking as compared with solid 
lumber as well as the ability to undergo severe carving, scrolling and 
fine detail work, while preserving an aesthetically desirable appearance 
and avoiding breaking, flaking and undesired edge disintegration. 
SUMMARY OF THE INVENTION 
The above described need has been met by the composite wood veneer article 
of the present invention. The composite article of the present invention 
provides upper and lower layers of wood veneer having grain orientation 
generally in a first direction. At least two layers of interposed wood 
veneer are provided with at least one such layer having a grain 
orientation offset from the first direction by about 10.degree. to 
25.degree., preferably about 15.degree. to 20.degree.. The adjacent layers 
of wood veneer are adhesively bonded, preferably substantially 
continuously, generally in surface to surface relationship. 
The composite wood veneer article of this invention has at least four wood 
veneer layers. Where two interposed layers are provided, both may be 
offset from the first direction by about 10.degree. to 25.degree.. These 
interposed layers may be offset on opposite sides of the first direction. 
In one embodiment of the invention, three interposed layers may be provided 
with all of them being offset by about 10.degree. to 25.degree.. In the 
alternative, one or more of the interposed layers may having grain 
orientation aligned generally with the first direction. 
The composite wood veneer article of the present invention may be generally 
flat or curved and is preferably substantially rigid. 
It is an object of the present invention to provide a composite wood veneer 
article with improved strength and machine workability without meaningful 
impairment of the aesthetically desirable characteristics of the 
structure. 
It is a further object of this invention to provide such an article which 
is adapted to have increased strength in respect of solid lumber as well 
as resistance to undesired chipping and cracking. 
It is yet another object of the present invention to provide a composite 
wood veneer article which may be subjected to carving, scrolling, even to 
small tolerances, without production of an unsightly appearance, 
particularly in the edge portion. 
It is yet another object of the present invention to provide a composite 
wood veneer article which is adapted for painting, staining and other 
finishing more readily than is the case with conventional plywood, while 
permitting the use of conventional finishing procedures and materials. 
It is yet another object of the present invention to provide a composite 
wood veneer article which will resist warpage and have uniform expansion 
and contraction characteristics similar to that of conventional solid 
lumber, and also will provide improved resistance to warpage as compared 
with solid lumber. 
It is yet another object of this invention to provide the foregoing 
benefits in respect of properties while preserving the desirable aesthetic 
appearance of solid lumber. 
These and other objects of the invention will be more fully understood from 
the following description of the invention on reference to the 
illustrations appended hereto.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now more specifically to FIG. 1, there is shown a composite wood 
veneer article 2 in the form of a generally rectangular piece of composite 
lumber-like article. The article 2 has an upper veneer layer 4, a lower 
veneer layer 10 and two interposed veneer layers 6, 8. The upper veneer 
layer 4 has a grain oriented generally in a first direction which is 
indicated by the arrow. While not shown in FIG. 1, the grain orientation 
of lower layer 10 is also generally in the first direction (indicated by 
the arrow). 
Referring now to FIG. 2, there is shown a cross sectional illustration of 
the composite wood veneer article 2 of FIG. 1. Adjacent wood veneer layers 
are secured in generally surface to surface relationship by means of a 
suitable adhesive (not shown). In the form illustrated in FIG. 2, all of 
the wood veneer layers 4, 6, 8, 10 are of the same thickness. This 
thickness may be about 1/64 inch to about 3/8 inch and preferably is about 
1/20 inch to about 3/16 inch. If desired, different layers may be made of 
different thicknesses. For example, it may be desirable to provide a 
relatively thin upper layer 4 and lower layer 10 of a relatively 
expensive, decorative wood and thicker interposed layers 6, 8 of one or 
more different woods. 
In the form illustrated in FIGS. 1 and 2, each of the layers 4, 6, 8, 10 is 
generally rectangular and of generally the same length and width so as to 
provide a composite wood veneer article having the layers 4, 6, 8, 10 with 
generally aligned marginal edges. 
FIG. 3 illustrates an exploded view of the four layers 4, 6, 8, 10 employed 
in constructing composite wood article 2. It is noted that upper layer 4 
and lower layer 10 each have a wood grain oriented generally in first 
direction "A". Interposed layer 6 has a wood grain oriented in direction 
"B" which is offset from direction "A" by an included angle x which is 
equal to about 10.degree. to 25.degree. and is preferably about 15.degree. 
to 20.degree.. Similarly, interposed layer 8 has its grain oriented at 
direction "C", which is offset from first direction "A" by an included 
angle y which is also about 10.degree. to 25.degree. and preferably about 
15.degree. to 20.degree.. While the angle x may equal the angle y, and 
such an approach may be preferable in instances where symmetry of 
properties is of importance, such equality is not necessary provided that 
both angles remain within one of the recited ranges. In the form shown in 
FIG. 3, it is noted that direction "B" is offset from first direction "A" 
on one side thereof, and direction "C" is offset from direction"A" on the 
other side. If desired, both direction "B" and "C" may be offset from 
first direction "A" on the same side thereof, but in the interest of 
obtaining symmetry of properties about the first direction "A", it is 
generally preferred to have directions "B" and "C" offset on opposite 
sides of direction "A". If desired, either interposed layer 6, 8 could 
have a grain orientation in direction "A", but at least one of the 
interposed layers 6, 8 must have a grain orientation offset within the 
recited ranges of angles. 
The invention provides a composite wood veneer article which is 
substantially rigid and has improved strength as compared with comparable 
lumber of the same dimension and wood selected. By providing specifically 
positioned grain orientations which are offset in interposed layers 6, 8, 
and upper and lower layers 4, 10 having grain orientations in a first 
direction, it is possible to preserve the desirable appearance of ordinary 
lumber while providing improved strength. All of this is accomplished by 
use of a composite veneer construction having at least four veneer layers 
with the specifically disclosed, relative grain orientations in an 
adhesively bonded assembly. 
Referring now to FIG. 4, there is illustrated an exploded view of another 
version of the invention which employs five veneer layers to create a 
generally flat composite wood veneer article. In external appearance, when 
assembled, the embodiment of FIG. 4 may appear very much like the 
embodiment shown in FIG. 1, except for the presence of an additional 
veneer layer. In the form shown in FIG. 4, upper layer 14, interposed 
layer 18 and lower layer 22 all have grain orientations generally in the 
first direction "A". Interposed layer 16 has a grain orientation in 
direction "D" which is offset from direction "A" by an angle z which is 
equal to about 10.degree. to 25.degree. and preferably about 15.degree. to 
20.degree.. Interposed layer 20 has a grain orientation in a direction "E" 
which is offset from first direction "A" by angle z, also. As has been 
noted above, while the two offset grain orientation directions "D", "E" 
are shown as being on opposed sides of first direction "A", there could be 
provided on the same side of first direction "A", if desired. Also, in 
this embodiment, the angles of offset are both illustrated as being equal 
to angle z, if desired, the angles could be different provided they remain 
within the recited ranges. 
While in the form shown in FIG. 4, interposed layer 18 has a grain 
orientation in direction "A" and interposed layer 16, 20 have offset grain 
orientation, it will be appreciated that other combinations of relative 
grain orientation may be provided. All that is required is that at least 
one interposed layer 16, 18, 20 has a grain orientation offset from first 
direction "A" by the recited ranges of angles. It is, however, preferred 
that, in a five-layer wood veneer article, that at least two such offset 
grain orientations be provided, and it is further preferred that they be 
offset on opposite sides of first direction "A". 
In the preceding discussion, the description of the composite wood veneer 
article has been with reference to a generally rectangular, substantially 
flat lumber-like article. It will be appreciated, however, that, if 
desired, the article may consist of a curved composite wood veneer article 
constructed essentially as described above except for its being formed 
into a simple or compound curved contour. It will be further appreciated 
that in view of the increased strength of the article of this invention as 
compared with solid lumber, coupled with the fact that even finely 
detailed scroll and carving work does not destroy the desired edge finish, 
a wide range of wood articles in the nature of finished or semi-finished 
products may be made from the basic wood article, and such articles are 
encompassed within the present invention. While several specific examples 
will be discussed hereinafter, the invention is not so limited. 
Referring now to FIGS. 5. and 6, there is shown a composite wood veneer 
article 24 in the form of a wooden ring which has an outer periphery 26 of 
generally circular configuration and an inner periphery 28 of generally 
circular configuration defining opening 30. As is shown in FIG. 6, the 
ring 24 consists of upper layer 32, lower layer 38 and interposed layers 
34, 36 and has a generally circular cross sectional configuration. It is 
contemplated that upper layer 32 and lower layer 38 will have grain 
orientation in first direction "A", and that at least one of, and 
preferably both of, interposed layers 34, 36 will have a grain orientation 
offset from first direction "A" by about 10.degree. to 25.degree. and 
preferably from about 15.degree. to 20.degree.. 
The ring-like composite wood veneer article of FIGS. 5 and 6 may 
conveniently be made by first constructing an article such as that shown 
in FIG. 1 and subsequently blanking a disc from the article with the 
center being removed either prior to blanking or subsequent thereto. In 
the form shown in FIG. 6, the outer periphery 26 and inner periphery 28 
may conveniently be provided with a curved surface by machining with a 
wood router bit. Subsequently, suitable sanding and painting, staining or 
other finishing may be accomplished. The final product is strong and is 
aesthetically pleasing. 
Referring now to FIGS. 7 and 8, an example of the use of carved and 
scrolled composite wood veneer articles of this invention will be 
considered. Selected for purposes of illustration is the sort of unit 
which might be employed to provide a chairback or other decorative portion 
of an article of furniture or other article, when a suitable number are 
assembled in the proper orientation. Generally U-shaped member 40 has a 
pair of upwardly projecting legs 44, 46 and generally U-shaped member 42 
has a pair of downwardly projecting legs 48, 50. Each of these members 40, 
42 has been separately fabricated by carving and scrolling from a 
lumber-like article such as article 2 shown in FIGS. 1 and 2. They may be 
fabricated by conventional wood-forming technique, provide improved 
structural strength and do not deteriorate aesthetically when subjecting 
to the carving and scrolling required to fabricate the shape. The members 
40, 42 may be secured to each other by any suitable means such as an 
adhesive, screws or other fastening means. As is shown in FIG. 8, U-shaped 
member 42 has upper layer 52 and lower layer 58 with grain orientation 
(not shown) generally in first direction "A". At least one of interposed 
layers 54, 56 has an offset grain orientation which establishes an angle 
of about 10.degree. to 25.degree. and preferably about 15.degree. to 
20.degree. with respect to first direction "A". 
Referring now to FIGS. 9 and 10, there is shown a unitary composite wood 
veneer article in the form of a slingshot body. The sling-shot body has a 
handle or grip portion 62 and a pair of upwardly projecting spaced arms 
64, 66. This construction may advantageously be made from a unitary 
generally flat lumber-like composite veneer article such as that shown in 
FIG. 1. It provides the advantage of increased strength for an article 
where strength is important, coupled with an aesthetically pleasing finish 
which also eliminates the ragged edges which might result were plywood to 
be employed in the absence of the extra burden and expense of attempting 
to refinish after carving and scrolling. In this particular end use, the 
ragged edge is of consequence not only in terms of aesthetics, but also 
the possibility of injury to the user through splinters. 
As has been noted above, another advantage of the article of the present 
invention is the ability to fabricate the same employing conventional 
equipment, and, as a result, not involving the investment in additional 
capital equipment. As is shown schematically in FIG. 11, a conventional 
press having a press ram or platen 68 and press base 70 may be employed to 
establish a composite wood veneer article having upper layer 72, lower 
layer 78 and interposed layer 74, 76 by applying a suitable adhesive 
between each pair of adjacent veneer surfaces and applying a predetermined 
press pressure at either elevated or room temperature to produce a 
substantially flat composite wood veneer article such as article 2 shown 
in FIG. 1. Similarly, as is shown in FIG. 12, complementary curvature may 
be provided in press elements 80, 82 in order to establish a curved 
composite article from upper veneer layer 84, lower veneer layer 90 and 
interposed veneer layers 86, 88. 
As the present invention contemplates the use of any number of wood veneer 
layers provided at least four are employed, a further example showing a 
six-layer composite article is shown in FIG. 13. In this embodiment, in 
the form shown in FIG. 13, upper layer 92 and lower layer 102 have grain 
orientations generally in first direction "A". The interposed layers 94, 
96, 98, 100 have grain orientations offset from first direction "A" with 
the direction of offset being alternated between adjacent layers. 
Interposed layer 94 has a grain orientation generally in the direction "F" 
which is offset to the right of the direction "A" by an included angle m. 
Interposed layer 96 has a grain orientation generally in a direction "G" 
offset to the left of first direction "A" by included angle n. Interposed 
layer 98 has a grain orientation generally in direction "H" offset to the 
right of first direction "A" by an angle o. Interposed layer 100 has a 
grain orientation generally in direction "I" which is offset to the left 
of first direction "A" by an included angle p. Angles m, n, o, p will be 
about 10.degree. to 25.degree. with about 15.degree. to 20.degree. being 
preferred. For maximum symmetry of properties, where desired, the angles 
m, n, o, p will be either equal or of generally similar magnitudes, but 
all will fall within the recited ranges. If desired, only one of the 
interposed layers 94, 96, 98, 100 or less than all four thereof may have 
its grain orientation offset by an angle falling within the recited range. 
It is preferred that at least three of the four interposed layers 94, 96, 
98, 100 have a grain orientation offset for improved strength. 
Reference is now made to FIGS. 14 and 15 in order to illustrate further 
advantageous features of the invention. There is shown a generally 
H-shaped article 110 of the present invention which, in plan, is generally 
of the same shape and dimensions as the composite article shown in FIGS. 7 
and 8. It has legs 112, 114, 116, 118 and defines a central opening 120. 
Unlike the article of FIGS. 7 and 8, which is made by assembling members 
40, 42, the article 110 of FIGS. 14 and 15 is made from a unitary piece of 
composite wood veneer by carving and scroll work. It is strong, remains 
aesthetically pleasing and eliminates the need for joining separate 
elements. 
A further difference between article 110 of FIGS. 14 and 15 and the article 
of FIGS. 7 and 8 is that the former has been provided with a predetermined 
curvature. This will serve to provide an additional functional and 
decorative variation which is facilitated by the present invention. It is 
further noted, as is shown in FIG. 15, that four layered article 110 has a 
generally rectangular cross section as distinguished from the circular 
cross section of FIG. 8. By making the lumber-like composite wood veneer 
article generally of the desired final thickness of article 110, this 
rectangular cross section is readily established while reducing the amount 
of additional shaping required to provide the desired rectangular cross 
sectional shape. 
FIGS. 16 and 17 illustrate a modified slingshot body construction which is 
provided with a generally rectangular cross sectional configuration as 
distinguished from the generally circular cross section of FIGS 9 and 10. 
The slingshot body has a handle or grip portion 124 and a pair of upwardly 
projecting spaced arms 126, 128. FIG. 17 shows the four layered 
rectangular cross sectional shape which, in the form shown, extends 
through the grip portion 124. An economic advantage may be obtained in 
this form as it eliminates the need to establish the circular cross 
section illustrated in FIG. 10, and the original lumber-like composite 
veneer article from which it is made may be made to correspond in 
thickness with the desired thickness of the slingshot body. 
The wood veneer which is employed in creating the composite wood veneer 
article of this invention may be selected from a wide range of wood 
materials depending upon the properties required, the particular end use 
contemplated, and economic considerations. Among those preferred for most 
uses are woods selected from the group consisting of maple, walnut, ash, 
poplar, cherry, oak, mahogany, pine and birch. If desired, as has been 
noted above, for economic reasons or other reasons, the species of wood 
employed may be different for different veneer layers. For example, a high 
strength, relatively inexpensive wood may be employed in interposed 
interior layers, and a relatively expensive, attractive wood may be 
exposed for exterior reexposed layers. In addition, if desired, the veneer 
thickness of the layers may be different. While in general, the preferred 
thickness for the veneer layers is about 1/64 inch to 3/8 inch, and a 
specifically preferred range of thickness is about 1/20 inch to 3/16 inch, 
in all instances, at least four veneer layers will be employed. The 
thickness selected for particular layers will depend to an extent upon 
some of the aforementioned economic, aesthetic and property 
considerations, but, in addition, will be determined to a certain extent 
by the desired overall thickness of the article and rigidity required. 
A further advantage of the present invention is its resistance to undesired 
warpage. It also provides uniform expansion and drying patterns similar to 
solid wood by permitting expansion across the grains uniformly as a result 
of the relative grain orientations in which the wood layers have been 
glued. 
It is contemplated that the adjacent layers of veneer will be secured in 
generally surface to surface relationship by means of a suitable adhesive 
(not shown), preferably applied as a continuous layer. While the 
particular adhesive being selected will frequently depend upon the 
intended end use, it is generally preferred to employ a water-resistant or 
water-proof adhesive which will effectively prevent loss of bonding during 
storage, subsequent working, handling and use in a wide range of 
environments over an extended period of time. If desired, a disbursant may 
be provided in the adhesive to increase the strength of the resultant 
article. One particularly suitable adhesive is that marketed under the 
designation "CL-8800 Fast Curing Resin Emulsion (Type II Bond)" sold by 
National Casein. This is a water-solvent type adhesive and is particularly 
suited to bonding porous and semi-porous materials and has a viscosity of 
about 500-4500 cps at 78.degree. F which makes it easy to apply. Among 
other suitable adhesives are those sold under the trademarks "GULF L100 
Formaldehyde Resin" and "Melamine MB-330". 
EXAMPLE 
A specific example of the manufacture of a composite article of the present 
invention will be considered. Four elongated, rectangular wood veneer 
plies are provided. Two of the rectangular plies have grains oriented 
generally longitudinally. The other two wood veneer plies have grains 
offset from the longitudinal direction by about 18.degree.. The wood 
veneer elements are of the same length and width as are dried to a 
moisture content of about 6 to 10 percent. Both surfaces of the two veneer 
plies having offset grain orientations are covered with a continuous layer 
of an adhesive. The four veneer layers are placed together in such fashion 
that the longitudinally oriented grain elements provide upper and lower 
veneer layers, and the offset grain veneer layers are interposed with the 
offset of each of the two layers being about 18.degree. and being on 
opposite sides of the longitudinal grain direction. The marginal edges of 
the four veneer layers are aligned, and the assembly is placed in a 
conventional press. Approximately 100 lbs. per square inch pressure is 
applied substantially continuously to the entire assembly by means of the 
press while the assembly is essentially at ambient room temperature. After 
about twelve hours in a cold press which is sufficient to permit the 
adhesive to set, the press is opened and the composite wood veneer article 
is withdrawn. Subsequent carving, scrolling or other fabrication of 
semi-fabricated or completed wood article may then be commenced if 
desired. 
It will therefore be appreciated that the present invention provides a 
unique composite wood veneer article having improved strength properties, 
improved workability by conventional equipment and methods without 
undesired destruction of the appearance. All of this is accomplished in an 
economical fashion which permits the use of relatively inexpensive filler 
woods in producing a rigid, high strength, aesthetically pleasing article. 
For the purposes of illustrations, certain specific end uses, shapes and 
products have been disclosed, it will be appreciated that a wide range of 
semi-fabricated and fully fabricated articles may be made from the 
composite wood veneer article in lumber-like form. For example, various 
decorative wall hangings, rifle stocks, components for articles of 
furniture, curtain rings, bracelets and other decorative and functional 
items may be produced. Also, the basic lumber-like composite veneer 
article need not be generally rectangular in plan, but may readily be made 
in other desired shapes. 
While for purposes of simplicity of disclosure herein, reference has been 
made to "upper layers", "lower layers" and the like, these terms have been 
employed for convenience of reference in of relative positioning of these 
elements in respect to the interposed layers, and in the absence of 
express contrary indications are in no fashion to be interpreted as 
limiting on the invention. For example, it may be desirable in certain 
uses to place additional materials over the upper layer or under the lower 
layer. 
Whereas, particular embodiments of the invention have been described above 
for purposes of illustration, it will be evident to those skilled in the 
art that numerous variations of the details may be made without departing 
from the invention as defined in the appended claims.