Note: Descriptions are shown in the official language in which they were submitted.
~197 lL93
This invention is directed to a method and apparatus
for producing a reinforced laminated wood product. More
particularly, this invention is directed to a method of
extruding from peeled logs a plurality of wood strips
which are subsequently pressed and glued together to produce
a laminated wood product.
BACKGROUND OF THE INVENTION
It is well known that common wood products in
the form of lumber, and other materials used in construct-
ing building such as houses, and the like, are not absolutely
dimensionally stable, and shrink and expand with changes
in humidity. Moreover, the wood products tend to warp
and distort with fluctuations in humidity and temperature.
Lumber is ordinarily dried in a stleam kiln, but even with
such processing, the lumber still tends to warp and experience
changes in dimension with time. These difficulties, in
many cases, can cause distortion of the floors, walls
and ceilings of the building resulting in the cracking
of plaster or wall facings, which is unsightly, and weakens
the strength of the structure.
Another fault with well known wood products is
that wood is not a consistent product and may have a variable
number of knots, and grain imperfections, which reduce
the strength of the lumber. Generally speaking, trees
suitable for rendering into lumber products usually must
be of considerable maturity in order to provide reasonably
good even grain direction, and a low number of knots.
With the passage of time, and the increasing use of wood
products throughout the world, mature stands of trees
are becoming less plentiful.
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97~L93
Building a home from wood products has a perennialproblem in that constructing the home is labor intensive.
The services of professional carpenters must be utilized
in laying the joists, subfloor and floors of a normally
constructed home, using nails or other fastening methods
such as screws, well known in the home construction field.
As a result, there is a very high percentage of labour
costs involved in erecting a house.
The disadvantages of normal lumber products
have been known for many years, and many lumber substitutes,
such as plywood, ahip board, particle board, ancl the like,
have been developed. ~lowever, most of these products
are very expensive, or are inferior to lumber in their
performance.
SUMMARY OF THE INVENTION
I have invented a laminated wood product which
provides a good substitute for lumber. In producing -the
wood substitute, I have discovered that debarked raw wood
(wood that has recently been cut and still has a relatively
high sap content) can be extruded in the direction of
the grain through a parallelogram-shaped (and preferably
rectangular) grid work of cutting blades to form a plurality
of small wood strips of generally parallelogram-shaped
cross section of any specified length. Moreover, I have
found that various types of wood which are not now normally
used in the construction business, such as aspenite (poplar)
spruce and birch can be used in my invention. These types
of wood are in plentiful supply and relatively inexpensive
because they are not in demand as construction materials.
My method consists of passing or extruding under
high pressure in the direction of the grain a debarked
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or peeled log of aspenite, or other suitable wood, through
a parallelogram-shaped grid work of cutting blades, whereby
the log is formed into a plurality of wood strips of generally
parallelogram-shaped cross section. The extrusion process
is assisted if the wood strips emerging from the grid work
are firmly held and pulled with a force that is approximately
equal to the force being applied on the log to force it through
the grid work. Moreover, raw wood which has a lower sap
content can be extruded in my processs more readily than
a log with a high sap content.
Generally, the wood strips that are obtained
are of more or less the same length as the log which is
used to extrude the wood strips. I then take the extruded
wood strips and cure them at a temperature of about 200F.
for about two hours, which is considerably less time than
is ordinarily used to cure lumber. During this process,
the strips become twisted and somewhat resemble spaghetti
or noodles. ~owever, this twisting presents no problem
because the strips can be easily straightened out using
a~press.
Preparatoryto extrusion, the logs should be
debarked or peeled. Otherwise, the bark tends to collect
as a thick tight mat on the grid work and greatly reduces
the efficiency of the extrusion process.
The strips, if o~ square cross section, can be
grouped together so that there are sets of the strips passing
in generally the same direction. The strips are coated with
glue and then glued together under pressure using a suitable glue
such as epoxy, urea formaldehyde or phenol formaldehyde. Epoxy
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and phenol formaldehyde glues are preferred if the wood
product is destined for ultimate use outdoors. Of the
two, epoxy type glues appear to have better characteristics.
A strong laminated product can be found by having sets
of the wood strips in each layer extend in alternating
directions.
I have found that my laminated wood product
can be produced in virtually any required length or width.
~y process also has the advantage in that not more than
about 10 percent of the original log that is extruded
into the strips is discarded. This is a substantial
reduction over ordinary techniques for producing lumber
where when a log is sawn into planks, and the like, generally
about 33 percent of the log is lost and must be used in
scrap wood applications such as chip board and the like.
Another advantage of my product is that less
glue is required than in other substitute wood products
such as particle board and chip board. In common chip
board, the glue content usually ranges from 40 to 60 percent.
On the other hand, in my extruded wood strip product,
the glue content is usually in the range of 30 to 35 percent
of the finished product.
A further advantage of my process is that when
the peeled log is extruded through the blade grid, all
knots in the wood of significant size are either cut into
small pieces, or are popped out of the wood. Subsequently,
when the wood strips are cured, the cut knots, unless
they are very small, separate themselves from the wood
strips. Accordingly, the wood strips do not normally
contain any knots, which would contribute to weakness -~
in the finished laminated wood product.
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A well known problem with common chip board
is that because of its high glue content, usually urea
formaldehyde, screws and nails are not held securely by
the chip board. The nails or screws with time tend to
work free from the chip board. Because my laminated product
has a reduced proportion of glue, the nail and screw holding
characteristics of my product are much higher than with
common chip board.
After the extrusion step, the wood strips are
sorted, cleared of knots, and joined into long lengths.
They are then kiln dried, as mentioned previously, at
a temperature of about 200F. for about two hours. These
curing conditions are usually sufficient to reduce the
moisture content of the wood strips below about 12 percent.
Once the strips have been cured, tlley are removed and
placed in parallel rows of four or more, following which
glue in the form of epoxy or phenoL or urea formaldehyde
is applied. The group of strips coated with glue are
then pressed together under high pressure. In this way,
wood modules made up of my laminated wood strips can be
produced.
Normally, I prefer to form the wood strips into
flat modules, which can be directly substituted for lumber.
In other words, thick planks or plates of wood are produced.
However, the plurality of wood strips can be pressed and
glued together to form round logs, or fliches. Both of
these latter items can be peeled by ordinary plywood manu-
facturing techniques for use in the production of plywood.
The elongated wood strips of my invention can
also be glued and pressed in a suitable press to form
laminated floor panels, which have reinforcing floor joists
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1~97193
Integrally molded underneath the panels as part of the
floor-type panel. Floors in homes made from such floor
panels do not require reinforcing or floor joists, as
is now the case with conventional lumber and plywood
products and conventional house erecting techniques.
Finally, my process can also be used for woods
which are considerably harder than aspenite and birch, for
example, oak. Prior to extrusion, the oak log is boiled
in order to soften it sufficiently for extrusion through
the blade grid work.
The method of extruding logs into a plurality ;~
of wood strips comprises extruding a peeled uncured log
in a direction along the grain of the log ~hrough a reinforced
parallelogram-shaped and preferably rectangular grid of ~;~
intersecting cutting blades which form a series of apertures. ;
The pressure of extrusion must be sufficient to force the
log through the apertures, thereby extruding the log into a
plurality of wood strips. The extrusion process proceeds
more easily if the wood strips emerging from the apertures
~n are firmly held and pulled with a force that is approximately
equal to the force being applied to the log to force it ;
through the apertures. The apertures formed by the intersecting
cutting blades can be square in shape. Moreover, the leading
cutting edges of the cutting blades can be nonlinear. The
cutting blades can be reinforced by primary and secondary
support grids.
An uncured log can be extruded through the grid of
intersecting cutting blades by means of one or more hydraulic ~;
,: .
rams which force the blades through the length of the log.
The moisture content of the wood may be reduced to below
about 12%, by kiln drying the strips at a temperature of
about 200F for about two hours for example, and the strips
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can be pressed together to form a wood module, which may be
bonded together to form laminated wood products. The glue can
be selected from epoxy, urea formaldehyde, phenol formaldehyde,
or any other suitable wood glue.
The apparatus for extruding the uncured peeled
logs into a plurality of wood strips can comprise an elongated
frame, an end plate positioned at one end of the elongated
frame, at least one hydraulic ram which is located at the end
of the frame opposite the end plate and extends parallel with
the elongatecl frame in the direction of the end plate, and
a reinforced parallelogram-shaped grid of intersecting cutting
blades secured to the end of the hydraulic ram that extends
in the direction of the end plate.
The frame can include at least two parallel
tracks that extend in the direction of and meet with the
end plate, and the grid o the intersecting cutting blades
can travel on the two tracks. The intersecting blades
of the grid can be positioned to form square shaped apertures
between the blades. The grid of cutting blades can be
reinforced by primary and secondary support grids positioned
on the side of the cutting blade removed from the end
plate.
The primary and secondary support grids can
have a plurality of intersecting vertical and horizontal
supports which align with the intersecting blades of the
cutting grid. The primary support grid can have a bewer
number of vertical and horizontal supports than the respective
number of blades of the cutting grid, and the secondary
support grid can have a few number of vertical and horizontal
` 30 supports than the primary support grid.
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DRAWINGS
In the Drawings:
FIGURE 1 illustrates an overhead view of the
apparatus used to extrude the logs into elongated wood
strips.
FIGURE 2 represents an exploded view of the
grid work of cutting blades and primary and secondary
support grids.
FIGURE 3 shows a front view of a cutting grid.
FIGURE 4 shows a front view of a primary support
grid.
FIGURE 5 shows a front view of a secondary support
grid.
FIGURE 6 shows sections of vertical and horizontal
cutting blades.
FIGURE 7 shows a perspective view of ~ section
of the cutting grid with vertical and horizontal cutting
blades fitted together.
FIGURE 8 shows a perspective view of a laminated
wood strip product.
FIGURE 9 shows a perspective view of a laminated .,~
wood strip product with integral underlying supporting
joists.
'`
DETAILED DESCRIPTION OF THE INVENTION
Referring to Figure 1, the basic extruder 1
used for extruding a peeled raw log 8, of aspenite, birch,
spruce or the like, into a plurality of`elongated wood
strips 1OJ is equipped with two parallel tracks 2. The
log 8 is placed so that it rests between and in a longitudinal
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direction parallel with the two tracks 2. An end plate
3 is located at one end of the two parallel tracks 2,
and is securely fastened to the two tracks 2. Mounted
above and within the boundaries established by the two
parallel tracks 2, at the end opposite the end plate 3,
are two hydraulic rams 4 which telescope in a direction
parallel with the pair of tracks 2 and toward the log
8. These two hydraulic rams 4 are connected to a grid
system which is made up of a cutting grid 5p a primary
support grid 6, and a secondary support grid 7. The cutting
grid 5 is mounted so that it faces and contacts the log
8 in advance of the primary and secondary support grids
6 and 7.
The cutting grid 5, with its primary and secondary
supporting grids 6 and 7, is forced against the end of
the log 8 that is opposite end plate 3, by applying hydraulic
pressure to the pair of hydraulic rams 4. In this way,
the log 8 is extruded along its grain into a plurality
of elongated wood strips 10. The pair of telescoping
hydraulic rams 4 have sufficient extension that the cutting
grid 5, can pass the entire length of the log 8, until
it contacts end plate 3. End plate 3 is reinforced by
end plate reinforcing 9 to withstand the very high pressures
- involved. The peeled log extrusion process is assisted
if the wood strips 10 emerging from the grid 5 are firmly
held and pulled with a force that is equal approximately
to the force being applied to the three grids 5, 6 and
7. No apparatus for securing and pulling the wood strips
10 is shown but any suitable system known in the art would
30 be satisfactory. :
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Figure 2 provides a detailed exploded view of
cutting grid 5, primary support grid 6, and secondary
support grid 7. The unextruded log 8 is shown at the
right.
The cutting grid 5 consists of a plurality of
vertical cutting blades 11, which are arranged in parallel.
The plurality of vertical cutting blades 11 intersect
with a corresponding plurality of horizontal cutting blades
12, also arranged in parallel. In this way, a grid work
of vertical and horizontally extending cutting blades
is formed. When this cutting grid 5 is forced by high
pressure through the log 8, the log 8 is, in effect, extruded
into a plurality of elongated strips 10 (See Figure 1)
each having a square cross section. A certain degree
of extension takes place, particularly with logs that
have a high water content.
Because very significant pressures are involved,
it is necessary to prevent buckling or collapse of the
cutting grid 5 by reinforcing the cutting grid 5 with
a primary support grid 6, and a secondary support grid
7. This combination is capable o~ withstanding the high
pressures involved when the cutting grid 5 is forced through
the log 8.
Primary support grid 6, similar to cutting grid
5, is made up of a plurality of parallel disposed primary
vertical supports 13, and a corresponding plurality of
parallel disposed primary horizontal supports 14. The
vertical supports 13 and horizontal supports 14 intersect
with one another to form a grid pattern, similar to the
grid pattern of cut~ing grid 5. Since primary support
grid 6 is used for reinforcing purposes only and does
7193
not actually contact the log 8, and therefore does not
participate in the actual extrusion process, there is
a smaller number of vertical supports 13 and horizontal
supports 14, when compared with the number of vertical
and horizontal cutting blades 11 and 12 in cutting grid
5. However, it is important that the fewer number of
vertical supports 13 and horizontal supports 14 align
in position with the corresponding vertical blades 11
and horizontal blades 12 of the cutting grid 5 so that
there is no obstruction to the passage of the log 8 through
the cutting grid 5.
Secondary support grid 7, similar to prlmary
support grid 6, is also constructed of a series of parallel
disposed secondary vertical supporks 15, and parallel
disposed secondary horizontal supports 16. Again, since
these vertical and horizontal supports 15 and 16 are used
for reinforcing purposes only, they do not have to be
as plentiful in number as the cutting blades 11 and 12
in the cutting grid 5. However, as with primary support
.~ 20 grid 6, it is important that the vertical supports 15
and horizontal supports 16 are aligned with the vertical
cutting blades 11 and horizontal cutting blades 12 of
: cutting grid 5, so that no obstructions are presented
to the passage of the log 8 through the cutting grid net-
work. The thickness and strength of the primary support
grid 6, and the secondary support grid 7, must be sufficient
to withstand the substantial pressures that are created
against vertical and horizontal cutting blades 11 and
12, when the log 8 is extruded through the cutt.ing grid
3~ 5.
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Figure 3 shows a front or end view of the cutting
grid 5, with the vertical cutting blades 11, and hori-
zontal cutting blades 12, (on end) intersecting as shown.
The horizontal and vertical cutting blades 11 and 12 are
fastened within cutting grid frame 17. The corners of
the frame 17 have connecting plates 18. These connecting
plates 18 have holes therein, which can be used in order
to bolt, or secure in some other manner, the cutting grid
5 to the primary support grid 6 and the secondary support
grid 7.
Figure 4 shows a front or end view of the primary
support grid 6. The intersecting primary vertical supports
13 and primary horizontal supports 14 are mounted within
a primary support grid frame 19. As indicated previously,
the respective number of vertical supports 13 and horizontal
supports 14 is less than the respective number of vertical
cutting blades 11 and horizontal clltting blades 12 making
up the cutting grid 5. It will also be noted that the
respective primary vertical supports 13 and primary hori-
zontal supports 14 correspond in position with the respective
vertical and horiæontal cutting blades 11 and 12 of the
cutting grid 5. In other words, the primary vertical
and horizontal supports, although fewer in number, align
with the respective vertical and horizontal cutting blades
11 and 12. Connecting plates 20l similar to the connecting
plates 18 of the cutting grid 5, are located in the four
corners of the primary support grid frame 19. These con-
necting blades 20 are used to connect and align the primary
support grid with the cutting grid 5 and the secondary
support grid 7.
Referring to Figure 5, which illustrates a front
or end view of the secondary support grid 7, the secondary
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support grid 7 is made up of a set of secondary vertical
supports 15 which intersect with a corresponding set of
secondary horizontal supports 16. The intersecting secondary
vertical supports 15 and horizontal supports 16 are enclosed
in a secondary support grid frame 21. Although fewer
in number than either the horizontal and vertical cutting
blades of the cutting grid 5, and the horizontal and verti-
cal primary supports of the primary support grid 6, never-
theless the positions of the secondary vertical and hori-
zontal supports 15 and 16 are positioned so that they
align with the respective cutting blades and primary supports
of the cutting grid 5 and the primary support grid 6,
thereby presenting no obstruction to the advancement of
the log 8 through the overall grid complex. As with the
` cutting grid 5, and the primary support grid 6, discussed
previously, connecting plates 22 are located in the four
corners of the frame 21, and are used to connect and align
the cutting grid 5, the primary support grid 6 and the
secondary support grid 7.
~0 Figure 6 shows a section piece of a vertical
cutting blade 11, which is a component of the cutting
~ grid 5. The cutting edge of the vertical cutting blade -~
`- 11 is at the left. Since substantial pressures are involved,
it is advantageous to have the cutting blade sharpened
with a scalloped or uneven edge of some type. In this
way, the entire cutting edge of the blade 11 does not
contact the log 8 at one time. With an uneven cutting
edge, the cutting blade 11 is able to cut the log 8 with
lower initial pressure. The vertical cutting blade 11
(as can be seen in Figure 6) has a series of intersection
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slots 23 cut along its length and extending part of the
width of the blade 11.
The horizontal cutting blade 12, as shown in
Figure 6, also is sharpened so that it has a scalloped
or uneven cutting edge~ Cutting blade 12 has a correspond- ~.
ing number of intersection slots 24. The vertical cutting
blade intersection slots 23 and horizontal cutting blade
intersection slots 24 enable the vertical and horizontal
: cutting blades 11 and 12 to fit together as shown in Figure
7 to form a grid work of cutting blades.
Figure 8 shows a laminated wood strip board ~ ~:
25. The board 25 is formed with an upper layer 26 of
parallel wood strips, a middle layer 27 of wood strips
extending at right angles to the direction of the upper
wood strips in the upper layer 26, and a lower layer 28
of wood strips extending in the same direction as the
.; strips in the upper layer 26. This method of orienting
the three layers of strips gives the board 25 considerable
strength. The board 25 is formed by contacting the various
strips of wood in each layer with glue and gluing these
strips together under high pressure to form a unitary
block 25.
Figure 9 shows a wood strip board 29 which has
built-in reinforcing joists 30. These joists 30 can be
formed in one integral operation with the main body of
the strip board 29 by using a suitable mold and gluing
and pressing together the requisite number of wood strips.
Other forms of strip board can also be formed by gluing
together the elongated wood strips in various patterns,
and using appropriate molds for pressing and gluing the
strips into module wood productsO
The foregoing detailed description provides
a method and apparatus to enable a person to practise
my invention. However, it is not intended that the fore-
going description should be construed in a limiting manner
because it will be recognized that non-inventive variations
in both the process and the method can be made without
; departing from the spirit of my invention. Accordingly,
the scope of my invention is to be construed according
to the claims that follow this description, and any non-
inventive mechanical equivalents of the process and apparatus
of my invention.
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