Note: Descriptions are shown in the official language in which they were submitted.
CA 02402087 2002-09-09
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COMPOSITE WOOD CONSTRUCTION MEMBERS HAVING A TEXTURED
SURFACE AND APPARATUS AND METHOD FOR PRODUCING THE SAME
FIELD OF THE INVENTION
[001] The present invention relates to construction members, particularly
those
made from a composite wood material, the members having a textured surface,
and
to an apparatus and method for producing the same.
~o BACKGROUND OF THE INVENTION
[002] Traditionally, the construction industry has employed materials such as
wood,
steel and aluminum for construction members (such as 2"x4" and 2"x6"' members)
used for building structures and members such as beams, joists, rafters,
decks,
> > siding, fencing and the like. Wood has been one of the most popular
materials
because of its relatively low cost and ease of handling and use. However, wood
has
several drawbacks when used as a building material. For example, as an outdoor
building material, wood is subject to decay due to environmental factors such
as
moisture, sunlight, etc., and it has non-uniform strength characteristics due
to
2o discontinuities resulting from knots and the like. Additionally, as wood
supplies have
dwindled, the cost of wood has increased substantially.
[003] More recently, plastic building materials such as PVC have been
developE:d to
serve a similar purpose as existing wood materials. Plastic building materials
are
z~ more resistant to environmental factors and generally have a longer life
span.
However, plastic building materials also have several drawbacks compared to
their
wood counterparts, including aesthetic problems in that the plastic does not
look or
feel the same as wood. There are also safety problems in some applications
such
CA 02402087 2002-09-09
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as when used as flooring or decking, in that the plastic building materials
are
generally much more slippery than wood (i.e. have a lower coefficient of
friction).
[004] More recently there has been the development of composite wood building
s materials. Composite building materials are generally formed from a mixture
of
wood fiber and a plastic resin material. The two components are usually
combined
by heating and extruding under pressure. This process creates construction
members made from composite wood material. Such members will exhibit some of
the properties of both wood and plastic.
iu
[005) Composite wood members have many of the positive characteristics of both
wood and plastic, however, they also have some of the drawbacks. For example,
since composite building materials are generally extruded, their surfaces,
particularly
the outer surfaces, will often be relatively smooth. Since people are
accustomed to
Is the appearance of natural wood, this is considered by some people to be not
as.
aesthetically pleasing as the texture of natural wood. Additionally, the
surface is
also relatively slippery, somewhat like a plastic surface.
[006] Accordingly, there is a need for an improved composite wood construction
?o member that has a textured surface, which reduces the slipperiness of one
of more
of the surfaces, and improved methods and apparatus for making the same.
SUMMARY OF THE INVENTION
z, [007] It is therefore an object of this invention to provide an improved
composite
construction member, particularly one made from composite wood.
[008] According to one aspect of the invention, there is provided a member
made
from a composite wood material comprising an elongated body having at least
~o one outer surface and opposed side edges and a plurality of grooves formed
on
said outer surface.
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[009] According to another aspect of the invention, there is provided an
apparatus
for forming a textured surface on a member, said apparatus comprising: a
frame; a tool bit driving mechanism supported by said frame; a tool holder
s connected for lateral movement to said driving mechanism and adapted to be
supported over a surface of said member; at least one tool bit mounted to said
tool holder; wherein said driving mechanism moves said tool holder such that
said at least one tool bit forms grooves on said surface of said member as
said
member moves past said apparatus.
io
[0010] According to another aspect of the invention, there is provided an
apparatus
as claimed in claim wherein said plurality of tool bits are each mounted for
resilient vertical movement to said disc.
~s [0011]According to another aspect of the invention, there is provided a
method of
forming a friction-enhanced surface on a member, said method comprising:
forming longitudinal ridges on a surface of a composite or plastic building
member; forming lateral grooves on said surface of said member with said
apparatus.
[0012]According to another aspect of the invention, there is provided a method
of
forming a friction enhanced surface on a member, said method comprising:
feeding an elongated member longitudinally past an apparatus; forming a
plurality of arcuate grooves on a surface of said elongated member with said
2s apparatus.
[0013]According to another aspect of the invention, there is provided a member
made from a plastic or plastic composite material comprising an elongated body
~o having at least one outer surface and opposed side edges and a plurality of
grooves formed on said outer surface.
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[0014]According to another aspect of the invention, there is provided a method
of
forming a friction enhanced surface on a composite wood member, said method
comprising: a) Extruding or pultruding a composite wood member with a first
apparatus; b) Feeding said member past a second apparatus; c) Forming a
a plurality of grooves on a surface of said member with said second apparatus.
[0015]Other aspects and features of the present invention will become apparent
to
those of ordinary skill in the art upon review of the following description of
specific
preferred embodiments of the invention in conjunction with the accompanying
~o figures.
BRIEF DESCRIPTION OF THE DRAWINGS
(0016] FIG. 1 is a perspective view of a segment of a construction member made
Is from composite wood according to a preferred embodiment of the invention;
[0017] FIG. 2 is a side view of a preferred apparatus for texturing the
surface of
composite wood members according to an embodiment of the invention;
?o [0018] FIG. 3 is a top view showing the apparatus of FIG. 2, with some of
the
components omitted for clarity;
[0019] FIG. 4A is a side view of exemplary tool bits of the apparatus of FIG.
2 in
interaction with the construction member of FIG. 1;
?s
[0020] FIG. 4B is a front view of the exemplary tool bits of the apparatus of
FIG. 2 in
interaction with the member of FIG. 1;
(0021]FIG. 5 is a schematic perspective view illustrating the interaction of
the tool
~o bits of FIGS. 4A and 4B with the construction member of Figure 1;
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[0022] FIG. 6 shows the construction member of FIG. 1 after processing with
the
apparatus of FIG. 2, to produce textured surfaces;
[0023] FIG. 7 is perspective view of part of the apparatus of FIG. 2 cut away;
(0024] FIG. 8 is a top plan view of part of the apparatus of FIG. 2 cut away;
and
[0025] FIG. 9 is a side elevation view of the part of Fig. 7.
to DETAILED DESCRIPTION
[0026] FIG. 1 shows an example segment of a construction member 10 that is
intended to be used in applications similar to a 2"x6" wood deck board. Member
10
is preferably formed by extruding or pultruding a heated composite wood
material
Is through a die. Examples of extrusion and pultrusion techniques that could
be
employed are disclosed in US patent nos. 5,782,125 to Bastone et al.;
5,096,406 to
Brooks et al; 5,965, to Fink and 5,234,652 to Woodhams et al., the contents of
each
being incorporated herein by reference. The material that is used is
preferably a
composite wood, such as is disclosed in US patent no. 3,888,810 to Shinomura.
?o
[0027]Construction member 10 preferably contains a multitude of generally
vertical
ribs 11 extending longitudinally along each member 10 between two elongated
walls
17a, 17b having flat outer surfaces 14a and 14b. Member 10 preferably has a
uniform cross-section throughout its length, as, for example, is detailed in
U.S. Pat.
?s No. 5,234,652, the contents of which are hereby incorporated herein by
reference.
Ribs 11 are preferably equally spaced apart and define rectangular shaped
chambers 13, extending parallel to one another between the flat surfaces 14a
and
14b along the length of member 10. Three, four or five chambers 19 are
preferred
for most decking applications.
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[0028] In the preferred embodiments, the dimensions of member 10 will be the
same
as conventional boards of lumber. Preferably, member 10 will be 2"x 3"; 2" x
4"'; 2" x
6"; 2" x 8"; 2" x 10"; or 2" x 12" in height and width, and have lengths which
may vary
depending on the particular application.
[0029] Of course, these specifications are merely examples of possible
embodiments and variations of these are possible.
[0030] Extending from the sides of each member 10, proximate the edges 13a,
13b
to of each flat surface 14a and 14b are lips 15a and 15b, respectively. The
member 10
has two opposed side faces 12a, 12b resulting from the outer facing side of
ribs 11 a.
[0031]As can be seen in FIG. 1, member 10 has been formed with longitudinally
spaced ridges 16, which run along the length of the wider surfaces 14a, 14b of
'the
is composite building member10. In this description, longitudinal is generally
used to
refer to the direction in which the composite building material 10 is being
extruded
and lateral is generally used to indicate a direction perpendicular or
substantially
perpendicular to the longitudinal direction and typically in the same plane or
a plane
parallel or substantially parallel to surfaces 14a and 14b of the composite
building
2o material 10. This type of member 10 is known and the longitudinal ridges 16
are
typically formed during the extrusion process by the shape of the extrusion
die.
[0032] It will be understood that, while the longitudinal ridges 16 might in
some
circumstances reduce slipperiness to some extent in the lateral direction,
they are
2s less effective at reducing slipperiness in the longitudinal direction (ie.
the direction of
the ridges 16).
[0033]With reference to FIGS. 2 and 3, an apparatus 20 is illustrated which is
exemplary of an embodiment of the invention. Apparatus 20 (referred to herein
as a
~o knurling apparatus) is configured with two separate knurling units 20a and
20b. In
this way, apparatus 20 can process both the upper surface 14a and lower
surface
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14b of member 10, at the same time. Since the upper and lower knurling units
20a,
20b are substantially the same, the following description will focus on the
upper
knurling apparatus 20a. Apparatus 20a can be configured in several different
ways
in relation to apparatus 20b. Apparatus 20a, can for example, operate
s independently of apparatus 20b, or be synchronized to run at the same speed,
either
in phase of out of phase with apparatus 20b.
[0034]The knurling apparatus 20 can be set up to be in line with the extrusion
equipment (not shown). The extrusion equipment is generally known and will not
be
~o described in detail herein. In this embodiment apparatus 20 is set up to
process
pre-cut members 10 that have been cut into specific lengths. Apparatus 20 is
positioned between a pair of stock feeding mechanisms 22a, 22b which move the
extruded composite member 10 in the longitudinal direction indicated by the
arrow
positioned on member 10 in FIG.2. Feeding mechanisms 22a, 22b generally
~s comprise a set of freely rotating lower rollers 23 mounted to a support
table 31.
Suspended above table 31 and rollers 23 is a set of drive rollers 25 which are
driven
in rotation by a motor 27. Rollers 25 and motor 27 are suspended on a frame
generally designated as 31. Frame 31 is mounted for adjustable vertical
movement
on a shaft 29. Members 10 are fed between rollers 23 and rollers 25, which act
as a
?o set of pinch rollers to move member 10 through the apparatus 20. Preferably
the
movement of member 10 caused by feeders 22a, 22b is continuous movement at a
constant speed. However in alternate embodiments the movement could be
intermittent and/or with a variable speed and could be controlled by a
computer
controller device. It is noted that the stock feeding mechanisms 22 are
vertically
2> adjustable to allow for members of different thickness of members 10, as
shown by
arrows near frame 31 in FIG. 2.
(0035]With reference to FIGS 2 and 3, the knurling apparatus 20 includes a
support
frame generally designated 24, a rotary drive mechanism 26 supported by the
frame
0 24, a rotatable tool holder 28 connected to the rotary mechanism 26, and
tool bits 30
connected to the tool holder 28.
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[0036]The rotary mechanism 26 may be a conventional electrical motor 40. The
rotary mechanism 26 is connected via a drive shaft 27 to the tool holder 28.
The
s tool holder 28 is supported by shaft 27 above member 10. In this embodiment,
the
tool holder 28 comprises a circular disc and supports a plurality of tool bits
30
around its circumference, mounted at a specific radius from the shaft. It
should be
noted that in some embodiments, the radius of the tool bits 30 may be
adjustable.
This adjustment could be achieved, for example, by having replacement discs
that
to could be substituted for existing discs.
[0037]The tool bits 30 carried on apparatus 20a are positioned such that they
will
come into contact with the surfaces 14a of the composite member 10 as it is
fed
through the knurling apparatus 20. Preferably the bits are mounted on tool
holder
I, 28 in a manner that they can be brought into a suitable vertical position
relative to
board surface 14a. For example, tool holder may be adjustable relative to
shaft 27.
Preferably, the tool bits 30 are easily detachable from the tool holder 28 so
that they
may be easily replaced if necessary. The preferred attachment/detachment
mechanism for tool bits 30 is described in further detail below.
zo
[0038] As illustrated in FIGs. 4A, 4B, 7, 8 and 9, tool bits 30 are mounted to
disc 29
in the following manner. Disc 29 has a radial channel 50 extending from
proximate
the center of disc 29, radially out to a location proximate peripheral
circumferential
edge 54. At the outer end of channel 50 is a rectangular slot 52, which opens
on
?> both the upper and lower surfaces of disc 29. Mounted within channel 50 and
extending from an inner mounting block 56 into slot 52 is a rod 58. Rod 58 is
made
from a relatively strong, resilient material like steel. End 50a is held in
cylindrical
opening 62 in mounting block 56 with a set-screw 64. Block 56 is mounted to
disk
29 with a mounting bolt 60.
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[0039] End 50b of rod 50 extends through an opening in a pillow block member
70,
into slot 52 and is threaded at its end portion 50b. Pillow block member 70 is
affixed
to disc 29 by conventional devices such as bolts. The opening in pillow block
70 is
sized so that rod 50 is generally in abutment with the upper or lower walls
forming
the opening (ie. there is substantially no play between rod 50 and block 70).
In this
way rod 50 is held in position within block 70, and given the deflected
position of rod
50, will tend to exert a force downward on the lower wall of the opening in
block 70.
However, block 70 is preferably made from a material which is itself somewhat
deformable, but which is also resilient, such as hi-strength, solid nylon.
to
[0040] In this way, when rod 50 travels over a surface 14a having relatively
large
changes in elevation, the force acting on rod 50 will be cushioned by block
70.
[0041] A strap member 78 is secured across the top of channel 50 and will act
to
n prevent large vertical movements of rod 50.
[0042] Each tool bit 30 includes a freely rotatable wheel 34 with an angled
edge 36.
Each wheel can simply be provided with a central opening and be received for
rotation on rod 50. Wheel 34 could be more complex in design being bearing
2o mounted with for example a center mounting portion which is mounted on the
end of
rod 58 and an outer peripheral bearing portion which has edge 36 and which can
freely rotate relative to inner mounting portion.. Wheel 34 is held in
position on rod
50 between threaded nuts 74, 76, and which do not prevent rotation of the
wheel.
?s [0043] As shown in Fig. 9, the undeflected position of rods 50 of both
upper unit 20a
and lower unit 20b are shown in broken lines. It will however be appreciated
that
when rod 50a of upper unit 20a is engaging the upper surface 14a of member 10,
it
is actually in an upwardly deflected position. Thus, a restoring force is
actually
acting on rod 50a causing it to push down on upper surface 14a. Rod 50a is
actually
~o acting like a cantilever beam, and so depending upon the amount of
deflection from
its undeflected position, the force will vary.
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[0044]As disc 29 rotates, each wheel 34 will roll across the surface of member
10,
much like a conventional rolling pizza cutter rolls over a pizza. The edges 36
are
designed to roll across the surface 14 of the composite building material 10
coming
s into contact with the already formed longitudinal ridges 16 to create
lateral grooves
38 in the longitudinal ridges 16. In this particular example, it is preferable
that the
tool bits 30 apply pressure onto the ridges 16, to deform the material to form
grooves 38. The action of bits 30 as they rotate over the surface of the
member 10,
is a rolling action that displaces material to the side, rather than a cutting
action
to where portions of material are sheared away. In other words the edges 36
roll over
the material that comprises the ridge and in that rolling action displace and
compress material to form the grooves 38. Due to the resilient nature of the
rod 50
and pillow block 70, wheels 34 will be able to come extent to move vertically
up and
down to follow the terrain of surface 14a.
>>
[0045] It is believed that this type of action will better preserve the
integrity of the
composite building material 10 as well as the Rife of the tool bits 30.
Additionally,
some people will consider this provides for a more pleasing finish to surfaces
14a
and 14b, as grooves 38 have nicely formed, non-jagged edges. Grooves 38 are
?o preferably formed in a generally v-shape, and preferably are about 1 mm in
depth.
This will have the desired effect of enhancing the amount of friction
developed when
another item comes into contact with a surface 14a (eg. a sole of a shoe).
(0046] It should be noted that the arcuate pattern of the grooves 38 will tend
to
2> create enhanced friction force in both the longitudinal and transverse
directions.
[0047]As the tool bits 30 are mounted at the E:nd of cantilever rod 50, the
tool bits
will be able to move vertically up and down over the terrain of the surface
14a of
member 10.
3U
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[0048] It is preferable that the texturing of the surface of member 10 takes
place
shortly after extrusion of member 10. For example, apparatus 20 could be put
in-
line with the extrusion apparatus. However, apparatus 20 can be configured to
still
achieve the desired results using the same functional mechanism, if the member
10
s is processed after the composite wood material has cured. Even after curing,
composite wood can be deformed by the edges 36 of wheels 34 during the rolling
action of the wheels.
[0049] FIG. 5 illustrates schematically the tool bits 30 of the knurling
apparatus 20 in
to operation. The tool holder 28 is rotated by the rotary mechanism 26. As the
composite wood member 10 proceeds through the knurling apparatus 20, the tool
bits 30 move laterally across the composite building material 10 at both a
leading
and trailing edge of the tool holder 28, creating arcuate grooves 38 laterally
across
the composite building material 10. The arcuate shape of the lateral grooves
38 will
is be either convex or concave in relation to the longitudinal direction
depending on
whether formed at the leading or trailing edge of the tool holder 28. It will
be
appreciated that as the member passes through apparatus 20 each surface 14a,
14b will be exposed to two passes of the tool bits 30. Thus on one pass the
arc to
the pass will be convex (when viewed from one end of member 10), and on the
zo other, the pass will be concave (when viewed from the same end of member
10).
[0050]As shown in Fig. 5, grooves 38 extend between edges 15a, 15a and 15b,
15b
and preferably extend all the way to/from the ridge 16 closest to each edge.
Zs [0051]The speed of rotation of bits 30, their radius of rotation, and their
spacing, in
relation to the speed of movement of member 10 longitudinally through the
apparatus 12 will produce a particular pattern on surfaces 14a, 14b. This
pattern will
vary depending upon the inter-relationship of these parameters. Preferably the
longitudinal speed of the board will be in the range of about 6-10 feet/min
when in-
30 line with the extrusion machine. Preferably there are 20 tool bits 30
mounted on a
disc 29 evenly spaced on disc 29 at a radius of about 18 inches from the
center of
CA 02402087 2002-09-09
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rotation. The disc 28 will preferably be rotated at a speed of in the range of
about
225 revs per min.
[0052] FIG. 6 shows the composite building material 10 having a textured
surface
14a comprising longitudinal ridges 16 and lateral grooves 38 forming a knurled
pattern and texture on the surface 14 of the composite building material 10.
The
knurled pattern and texture formed on the surfaces 14 of the composite
building
material 10 provides better slip resistance and at least some people will
consider it
improves the aesthetic look and feel of the composite building member 10.
~o
[0053] In the apparatus above, the knurled pattern and texture is formed by
first
creating the longitudinal ridges 16 and then adding arcuate lateral grooves 38
using
the knurling apparatus 20. However, it is possible to form a similar pattern
using
different arrangements of the apparatus. Further, the lateral grooves 38 may
be
formed in straight lines rather than in an arcuate pattern or may be formed
having
other patterns depending on the shape and speed of rotation of the tool holder
28,
the number of tool bits 30 provided on the tool holder 28, and other factors.
[0054] It will be understood by one of skilled in the art, that the knurling
apparatus 20
2o may be arranged either above or below the composite building material 10 or
both
depending on the surfaces 14 to be textured. If necessary, the knurling
apparatus
20 may also be arranged to provide texture to the edges of the composite
building
material 10. Such a knurling apparatus 20 may preferably be arranged adjacent
to
the knurling apparatus 20 as described abovE~
[0055]The knurling apparatus 20 has been described and illustrated for use
with
members 10 made from composite wood material and having a surface to be
processed having longitudinal ridges 16. However, apparatus 20 could be used
with
members that are made from other materials such as plastics like PVC. To form
the
3o grooves 38, the apparatus 20 might have to be adapted to provide for
cutting bits to
cut the grooves in the plastic material. Also, the apparatus 20 could be used
with
CA 02402087 2002-09-09
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members made from composite wood or other suitable material, which do not have
longitudinal ridges.
[0056]Although the knurling apparatus 20 described above can be used in line
with
an extrusion apparatus and prior to setting of the extruded composite building
material 10, it is also possible to arrange the H;nurling apparatus 20
separately from
the extrusion line process. In such a case, it may be preferable if the tool
bits 30 are
provided with a sharper edge for cutting into the composite building material
10 to
to form the lateral grooves 38.
[0057] Further, it will be understood that the knurling apparatus 20 and/or
tool holder
28 may also be adjustable in a vertical direction to allow for different
thicknesses of
composite building material 10. Further, the tool holder 28 or tool support 32
may
Is be supported or formed in such a way to allow for dimensional variances in
the
composite building member 10.
[0058] It will be further understood that the invention is not limited to the
embodiments described herein which are merely illustrative of preferred
embodiments of carrying out the invention, and which are susceptible to
modification
2o of form, arrangement of parts, steps, details and order of operation. The
invention,
rather, is intended to encompass ali such modification within its scope, as
defined by
the claims.
