Note: Descriptions are shown in the official language in which they were submitted.
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TITLE: FLOORING AND METHOD OF MANUFACTURING FLOORING
FIELD OF THE INVENTION
[0001] The invention relates generally to flooring and methods of
manufacturing flooring. In particular, the invention relates to flooring
comprising interlocking flooring tiles and methods of manufacturing such
flooring tiles and the mechanisms for interlocking them.
BACKGROUND OF THE INVENTION
[0002] Some kinds of finished flooring consist of a sub-floor and a
finished flooring layer supported by the sub-floor. The nature of a sub-floor
will vary depending on the flooring surface it needs to support and the
environment in which it must function. For example, for linoleum tile or
carpet
on a main floor of a house, the sub-floor may consist simply of sheets of
plywood. For a concrete floor such as commonly found in the basement of a
house, sheets of plywood would be inadequate alone as they would often be
subjected to moisture rising through the concrete floor of the basement, which
would tend to swell and warp the plywood. Accordingly, it may be desirable to
space the plywood from the concrete surface supporting the sub-floor in order
to allow for air circulation between the sub-floor and the concrete surface to
remove moisture that may otherwise swell the plywood.
[0003] Free floating sub-flooring panels that allow for air circulation
between the sub-floor and the concrete floor are described in United States
Patent Application Serial No. 09/809,307 by Smith, published under U.S.
Patent Publication no. 2002/0139074, the entire contents of which is hereby
incorporated by reference. Smith describes floor paneling for use in a sub-
floor application. The panels have an upper member made of a sheet floor
material, such as plywood, and a lower member made from a waterproof
sheet material, such as polyethylene. Smith describes interlocking the
flooring panels by mating a tongue on one panel with a groove on another
panel to prevent relative vertical movement between the panels. However,
Smith does not describe any way of maintaining the relative lateral positions
of the tiles, nor does Smith describe any way of laterally and longitudinally
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aligning the panels. Further, Smith describes panels suitable for establishing
a floating sub-floor, but the sub-floor of Smith cannot also act as finished
flooring. Rather, the panels of Smith must be overlayed with an insulating or
cushioning layer and then overlaid with carpet, hardwood, laminate, vinyl or
other flooring in order to achieve finished flooring.
[0004] Another problem encountered in providing flooring relates to
sound proofing. Some building codes require that flooring in condominiums,
for example, must provide a minimum degree of sound attenuation between
different floors of the condominium block. In Ontario Canada, the minimum
sound attenuation for hardwood flooring in condominiums is 60 dB.
Traditional hardwood flooring has inadequate attenuation of sound
transmission to meet these requirements.
[0005] To address this problem, it has been necessary to provide a
further three inches or so thickness of plywood and sound absorbing material
under the traditional 3/4 inch hardwood floor. This solution reduces the
volume of living space in the condominium. This also often generates
problems in matching the difference in heights between two flooring materials,
for example where the hardwood meets tiles in the kitchen or bathroom or
meets carpeted areas.
[0006] A further problem encountered in manufacturing wood flooring is
the waste associated with off-cuts generated by milling long wood planks to a
desired size. These off-cuts are commonly gathered into a large disposal bin
and the bin is removed by a specialist waste disposal company on a regular
basis such as weekly or monthly. The cost of such a waste disposal service
is substantial. Also the waste of valuable hardwood represents a further
financial loss. These problems are a concern among manufacturers of
hardwood flooring.
[0007] It is desired to address or ameliorate one or more of the
problems, disadvantages or shortcomings described above, or to at least
provide a useful alternative to existing products or techniques. Different
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aspects of the invention address these problems, disadvantages or
shortcomings in separate ways.
SUMMARY OF THE INVENTION
[0008] Aspects of the invention relate generally to flooring and to
methods of manufacturing flooring. These aspects relate to flooring
comprising interlocking flooring tiles or planks and to manufacturing such
interlocking tiles and, in come cases, their interlocking mechanisms.
[0009] In one broad aspect, the invention relates to flooring comprising
a plurality of tiles and at least one connector. The tiles each have a
plurality
of side edges and each side edge has a side face and a groove in the side
face extending along the side edge. Each connector has first and second
opposed side portions which are receivable in facing grooves of respective
tiles so that two tiles can be connected by one connector. Such a connection
can be made by having the first side portion of the connector received in the
groove of one of the tiles and the second side portion of the connector
received in the groove of another of the tiles. The flooring further comprises
retention means for retaining the first and second side portions in respective
grooves of adjacent tiles so that the adjacent tiles are positioned to have
their
adjacent side faces substantially abutting and aligned with each other. The
retention means acts to substantially hinder removal of the first and second
side portions from the groove. The tiles preferably comprise wood.
[0010] The flooring may further comprise, on each tile, a top veneer for
providing a walking surface. The top veneer may be, for example, a wood
veneer layer or a vinyl layer. The flooring may also comprise a spacing layer
on the underside of each tile for spacing the tiles from a support surface,
such
as a cement floor, underlying the flooring. The spacing layer is configured to
allow air to flow between the support surface and the flooring so that
moisture
coming up from the support surface can be removed by air circulation, rather
than by penetrating into the flooring and causing swelling and warping of the
flooring.
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[0011] Advantageously, the connector may be elongate, for connecting
the tiles along a substantial portion of the side edge to an adjacent tile, or
may
be cross-shaped (like a plus sign) for connecting the tiles at their corner
vertices. Such a cross-shaped connector also serves to provide lateral and
longitudinal alignment of the tiles, while the retention means, at least
partly
provided by the connector, maintains the relative position of the tiles in
such
an aligned state. For increased alignment and retention capability, both
elongate and cross-shaped connectors may be used. Alternatively, if an
elongate connector is used, a cross-shaped spacer piece may be used to
accomplish the alignment function, while the elongate connector serves to
maintain the relative positions of the adjacent tiles. In a further
alternative, the
cross-shaped connector may be used at the corners of the tiles while an
elongate spacer is used in place of the elongate connector.
[0012] Advantageously, embodiments of this aspect facilitate easy
alignment of the tiles in lateral and longitudinal directions and provide
connectors that, in combination with the grooves in the tiles, form retention
means such that the connectors grip the wood tiles or otherwise frictionally
engage the tiles to prevent or at least substantially hinder removal of the
connectors from the tile grooves.
[0013] The retention means may be provided by sizing the connectors
and groove so that the connectors are received in the grooves in an
interference fit. In such a case, the connectors preferably have angled
projections or teeth which press into the internal walls of the grooves
because
of the interference fit. The angled projections facilitate entry of the side
portions of the connectors into the grooves by being angled back towards a
central portion of the connector, but resist removal of the connector from the
grooves. Other forms of retention means may be employed, however, such
as by providing mating recesses within the grooves for receiving projections
on the connectors or by providing mating or interlocking contours of the
grooves and side portions of the connectors.
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[0014] Another broad aspect of the invention relates to flooring planks
and methods of manufacturing such flooring planks. In one particular aspect,
the invention relates to a flooring plank comprising a wood layer and a
substrate bonded to the wood layer. The substrate comprises a solid
polyethylene matrix and sawdust immobilized in the polyethylene matrix. The
sawdust comprises about 30-35% by volume of the substrate.
[0015] Preferably, the sawdust comprises about 32% by volume of the
substrate. The thickness of the flooring plank is preferably about 0.5 inches
and the thickness of the substrate is preferably at least 0.375 inches. The
thickness of the flooring plank may be greater than 0.5 inches if the
substrate
is greater then 0.375 inches but it is preferable to maintain the thickness of
the wood layer at about 0.125 inches. Preferably, tongue and groove portions
are formed in the substrate on opposite lateral sides of the plank.
[0016] In another particular aspect, there is provided a flooring plank
comprising a veneer layer and a substrate bonded to the veneer layer. The
substrate comprises a solid polyethylene matrix and sawdust immobilized in
the polyethylene matrix and the substrate has a thickness sufficient to
attenuate a least 60 decibels of sound from one face of the plank to an
opposite face of the plank. Preferably, the sawdust comprises between 30%
and 35% by volume of the substrate. More preferably, the sawdust comprises
about 32% by volume of the substrate. Preferably, the thickness of the
substrate is at least 0.375 inches. Tongue and groove portions are preferably
formed in the substrate on opposite lateral sides of the plank. The veneer
layer preferably comprises a hardwood veneer of about 0.125 inches in
thickness.
[0017] Another particular aspect of the invention relates to a method of
manufacturing flooring planks. The method comprises forming a substrate
comprising a solid polyethylene matrix and sawdust immobilized in the
polyethylene matrix, bonding a wood layer to the substrate and machining the
substrate and wood layer to form a plank.
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[0018] Preferably, the machining comprises forming tongue and groove
portions and a substrate on opposite lateral sides of the plank. The forming
step of the method preferably comprises mixing the sawdust with liquid
polyethylene and curing the polyethylene and sawdust to provide the solid
polyethylene matrix. The liquid polyethylene used to form the polyethylene
matrix preferably comprises recycled polyethylene material heated to
liquidation. The step of forming the substrate preferably comprises forming
the substrate to have a thickness sufficient to attenuate at least 60 decibels
of
sound from one face of the plank to an opposite face of the plank.
[0019] Advantageously, the substrate of polyethylene mixed with
sawdust has been found to provide good sound insulation properties at a
relatively small thickness. Additionally, the particular proportions of
sawdust
to polyethylene have been found to allow the substrate to be milled in a
similar manner to normal wood, thus allowing the substrate and wood veneer
layer to be milled together after they are bonded. Further, this allows the
tongue and groove of the plank to be milled into the thicker substrate portion
of the plank so that multiple planks can be fitted together according to
normal
flooring applications. A further advantage of this aspect is that it can use
recycled polyethylene material and sawdust, which are both cheap materials,
and only requires a relatively thin layer of hardwood veneer, rather than a
hardwood plank of normal 3/4 inch thickness.
[0020] Another broad aspect of the invention relates to a method of
manufacturing wood planks from waste wood. The method comprises
collecting elongate lengths of waste wood off cuts of at least a predetermined
size, applying adhesive to one side of the off-cuts, placing the off-cuts
together so that the off cuts are bonded together by the adhesive, pressing
the off-cuts vertically and laterally to form a plank and trimming and
smoothing
the plank.
[0021] Preferably, prior to the step of pressing, the bonded off-cuts are
planed to a substantially uniform thickness. The step of placing preferably
comprises axially rotating each of the off-cuts so that the adhesive applied
to
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the one side of an off-cut faces an adjacent off-cut and pressing the off-cuts
laterally together. The method preferably further comprises forming tongue
and groove portions along opposed lateral sides of each plank and forming
shallow grooves longitudinally along an underside of the plank. The top
surface of the plank is preferably finished as a walking surface. A further
aspect of the invention provides a flooring plank manufactured according to
the method described above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Aspects of the invention are described in further detail below, by
way of example only, with reference to embodiments shown and described in
relation to the drawings, in which:
[0023] Figure 1 is an exploded plan view of flooring according to one
embodiment;
[0024] Figure 2 is a partial plan view of the flooring of Figure 1 as
assembled;
[0025] Figure 3 is a partial cross-sectional view of a flooring tile and
connector, shown in assembled form;
[0026] Figure 4 is a partial perspective view of a flooring tile,
connectors and a spacer used in the flooring shown in figure 1;
[0027] Figure 5 is an exploded partial side cross-sectional view of
flooring according to another embodiment;
[0028] Figure 6 is a perspective view of an elongate connector for use
with the flooring of Figure 5;
[0029] Figure 7 illustrates an alternative form of connector and a
correspondingly shaped recess in a tile for receiving one side portion of the
connector;
[0030] Figure 8 shows a further alternative form of connector and a
mating recess formed in a tile for receiving one side portion of the
connector;
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[0031] Figure 9A is a partial and sectional view illustrating a further
form of connector, shown in an interference fit within the grooves of adjacent
abutting tiles.
[0032] Figure 9B is an end sectional view of the connector of Figure
9A;
[0033] Figure 10A is a plan view of a further alternative form of
connector;
[0034] Figure 10B is an end cross-sectional view of the alternative
connector of Figure 10A, taken along line B-B;
[0035] Figure 11A is an end view of a flooring plank according to
another embodiment;
[0036] Figure 11 B is a perspective view of the plank of Figure 11A;
[0037] Figure 12 is a process flow diagram of a method of
manufacturing the flooring plank of Figures 11A and 11 B;
[0038] Figure 13 is an end view of two pieces of flooring planks
manufactured according to a further embodiment;
[0039] Figure 14 is an end view of a flooring plank manufactured
according to yet another embodiment; and
[0040] Figure 15 is a process flow diagram of a method of
manufacturing the flooring planks shown in Figures 13 and 14.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0041] This invention has several separate main aspects. A first main
aspect relates to flooring, including tiles and connectors for connecting
those
tiles, as shown and described in relation to Figures 1-9A, 9B, 10A and 10B. A
second main aspect of the invention relates to flooring planks and a method of
forming such flooring planks to include a wood or veneer layer and a
substrate, as shown and described in relation to Figures 11A, 11 B and 12. A
third main aspect of the invention relates to a hardwood flooring plank and a
method of manufacturing such a plank using waste wood, as shown and
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described in relation to Figures 13 to 15. These three main aspects are
described in further detail below, separately and in sequence.
[0042] Throughout this specification and in the drawings, like reference
numerals are used to indicate like features or functions as between the
drawings and/or the elements as shown therein. Where practical, reference
numerals are structured so as to use the same number in the hundreds
column for like or related embodiments and to use the numbers in the
remaining two digit positions to indicate like features or functions as
between
different embodiments. Thus, for example, connectors are generally
designated by reference numerals ending in the number 20 as applied to the
first main aspect. For example, the connectors of the different embodiments
of the first main aspect shown in Figures 1, 5, 7 and 8 are designated by
reference numerals 120, 520, 720 and 820.
[0043] Embodiments of the invention relating to the first main aspect
will now be described, with reference to Figures 1-9A, 9B, 10A and 10B.
[0044] Figure 1 is an exploded plan view of flooring 100 according to
one embodiment. Flooring 100 comprises a plurality of flooring tiles or panels
110 interconnected by connectors 120. The tiles 110 are designed to be fitted
together in substantially the same plane so that their side edges abut the
side
edges of adjacent tiles. Tiles 110 are preferably about 2 feet by 2 feet
square
and composed of at least a main wood layer. The wood may be any form of
manufactured wood, for example such as random wafer board, oriented
strand board, plywood, particleboard or multi-density fiberboard.
[0045] While tiles 110 are shown in Figure 1 as being generally square,
it should be understood that they may be formed of other shapes, including
generally rectangular shapes, triangular shapes, pentangular shapes, or
hexagonal shapes, for example. Alternatively, tiles of more than one shape
may be employed together to form visually interesting patterns. Depending
on the particular tile shape chosen, the dimensions of tiles 110, connectors
120 and spacers 140 (described below) may vary.
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[0046] Tiles 110 preferably have a top veneer layer 115 (shown in
Figure 5), which is a finished flooring layer, such as a hardwood veneer,
laminate or vinyl bonded by suitable adhesive to the main wood layer. Tiles
110 also include a spacing layer 116 adhered by a suitable adhesive to a
lower surface of the main wood layer of tiles 110. Spacing layer 116 is water
impermeable and comprises a plurality of projections 177 projecting
downwardly from tiles 110 toward the concrete floor underneath the tiles 110
sides to separate the tiles 110 from the concrete floor. An example spacing
layer 116 is shown and described in US 09/809,307 by Smith. Projections
117 are spaced apart so as to allow airflow between the spacing layer 116
and the concrete floor. Thus, tiles 110 in conjunction with connectors 120 can
be used as sub flooring and finished flooring, thereby providing two functions
in one flooring product.
[0047] Tiles 110 have continuous groves 112 formed in their side
edges. The grooves 112 are continuous on each side edge of each tile 110
and meet at the corner vertices of each tile 110. Grooves 112 are preferably
shaped as channels having a roughly rectangular cross-section and being 1/4
inch across by about 3/4 inches to 19/32 of an inch deep (depending on the
lateral width of connector 120). The shape of groove 112 may be varied,
depending on the chosen mechanism for retaining connectors in groove 112.
Several such retention mechanisms are contemplated and described herein in
relation to certain embodiments.
[0048] Connectors 120 are formed as elongate extruded plastic inserts.
Each connector 120 has a lateral width greater than its thickness but
significantly less than its longitudinal length. Connectors 120 are preferably
made of a form of polyvinyl chloride (PVC). On each lateral side of each
connector 120 there are a plurality of outwardly projecting teeth 124, which
are angled back towards the lateral center of the connector 120. These teeth
124 begin at an end face 122 on each lateral side of connector 120 and
progress in series back towards the center portion of connector 120 on both
the top and bottom faces of connector 120. The thickness of connectors 120
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and the degree of projection of teeth 124 are sized to make an interference
fit
with the inside walls of groove 112. As shown in Figures 3 and 4, three teeth
129 may be provided on each lateral side and on each face. A greater or
lesser number of teeth may be used, depending on the particular
requirements of the retention means.
[0049] The teeth 124 of connector 120 are swept (angled) back in order
to facilitate entry of each lateral side portion into the respective grooves
112 of
adjacent tiles 110. The swept back form of teeth 124 in combination with the
interference fit also serves to substantially hinder removal of a connector
120
from the groove 112 of a tile 110 once it has been inserted therein. Thus,
connectors 120, in combination with grooves 112, serve to provide an
effective retention means for retaining tiles 110 in a particular orientation
or
position, once placed in such an orientation or position.
[0050] As shown in Figure 2, when the flooring tiles 110 are assembled
so as to adjacently abut each other using connectors 120, connectors 120 are
enclosed within the facing grooves 112 of adjacent tiles 110. Grooves 112
and connectors 120 are preferably sized so that each groove 112 is slightly
deeper than half of the lateral width of connector 120.
[0051] Also as shown in Figure 2, a spacer member 140 is used to
assist and aligning tiles 110 laterally and longitudinally with respect to
other
tiles. Spacer member 140 is received in grooves 112 adjacent the corner
vertices of each tile 110 and is shaped like a cross a or plus sign. Spacer
member 140 can be used to laterally and longitudinally align two, three or
four
tiles with each other as spacing member 140 has four concave vertices for
mating with prespective convex vertices of tiles 110.
[0052] Spacing member 140 is sized so as to be received in grooves
112 in a close fit but not an interference fit as, at least as shown in the
embodiment illustrated in Figure 2, spacing member 140 does not provide a
positive connection function in the manner of connectors 120. In other
embodiments, the spacer member may also provide a connection function, for
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example such as connector 1020 shown and described in relation to figures
10A and 10B.
[0053] Spacer members 140 also provide a leveling and support
function for tiles 110. For a situation where four tiles are connected by
connectors 120, an area of reduced tile thickness is formed around the point
where all four tiles meet and this area may become weaker as a result. By
having a spacer member 140 inserted in the grooves under the area where all
four tiles meet, the tiles 110 are supported against any weakness associated
with the area of lower tile thickness.
[0054] Figure 2 shows an area marked "A" , which corresponds to the
area marked "A" in Figure 4, showing a close up perspective view of a flooring
tile 110 with spacer member 140 partially inserted into grooves 112 adjacent
the corner vertex of tile 110. Figure 4 also shows connectors 120 inserted
into grooves 112 along adjacent side edges of tile 110. As can be seen from
Figure 2 and Figure 4, each cross-shaped spacer member 140 has two sets
of opposite wings 142 defining concave vertices 144 therebetween. Wings
142 extend partially along facing grooves 112 of adjacent tiles 110 when
spacer member 140 is located in position with its concave corner vertices 144
mating with the interior convex corner vertices of tiles 110 (created by the
intersection of grooves 112 on adjacent sides). Thus, the lateral width of
each
wing 142 is preferably the same as the lateral width of connectors 120 so that
spacer member 140 fits snugly into all intersecting grooves of all adjacent
tiles.
[0055] Although spacer member 140 is described and shown as being
cross-shaped, if alternative tile configurations (other than rectangular) are
used, for example such as triangular or hexagonal tiles the spacer member
may have an alternative shape and a different number of concave vertices. In
such instances, for triangular tiles, spacer member 140 may have six or eight
evenly spaced concave vertices or, for hexagonal tiles, spacer member 140
may have three equally spaced concave vertices.
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[0056] The terms "concave" and "convex" are used herein to indicate
any form of recess or projection, respectively, rather than to indicate that
there
is any particular curvature associated with the relevant feature. Thus
"concave" and "convex" as used herein include shapes having sharp angles
or corners.
[0057] Figure 3 shows a connector 120 inserted halfway into the
groove 112 of a tile 110. The other half of connector 120 would normally be
received in a facing groove 112 of an adjacent tile 110, although this is not
shown in Figure 3. As is visible in Figure 3, teeth 124 engage the interior
walls of groove 112 in an interference fit such that the teeth 124 cannot be
easily removed from groove 112. Connector 120 is shown in Figure 3 as
having its lateral end face 122 abutting an inner end wall 118 of groove 112.
In alternative forms of retention means, space may be provided between end
face 122 and inner and end wall 118. With the connector and groove
configuration shown in Figure 3, when the connector 120 is enclosed by
facing grooves 112 of adjacent tiles 110, the end faces 111 of the tiles 110
will
contact and abut each other.
[0058] Referring now to Figure 5, tiles 110 are shown employing a
slightly different form of retention means. In Figure 5, the retention is
accomplished by interlocking teeth 524 on connector 520 with corresponding
tooth shaped recesses 514 in the sidewalls of grooves 112. Connector 520 is
sized to be enclosed by grooves 112 when tiles 110 are brought together so
that their side faces 111 abut each other along the full length of each facing
side of the adjacent tiles 110.
[0059] Connector 520 is shown in perspective in Figure 6. Connector
520 is shaped like an elongate substantially rectanguloid bar with teeth 524
projecting from the top and bottom faces on each lateral side of the bar.
[0060] Referring now to Figure 7, an alternative form of retention
means is shown. In this alternative embodiment, tiles 710 receive one lateral
side of a connector 720 in a groove 712. The groove 712 has an internal
cross-sectional profile corresponding to projections on the lateral side
portion
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of connector 720. For example, groove 712 has recesses 714 formed to
cooperate with projections 724 on connector 720 in a similar manner to the
embodiment shown and described in relation to Figures 5 and 6.
[0061] Referring now to Figure 8, a further alternative form of retention
means is shown. In Figure 8, a connector 820 has side portions 824 on each
lateral side for interlocking with a groove 812 of tile 810. Groove 812 is
sized
so as to receive side portions 824 in a locking manner when connector 820 is
pressed laterally into groove 812. Groove 812 has an internal wall profile
that
tends to resist removal of side portions 824 from groove 812.
[0062] In the embodiment shown in Figure 8, side portions 824 are
generally circular in cross-section and groove 812 is contoured so as to
enclose the generally circular side portion 824 by contact with the internal
walls of groove 812, while allowing the central portion of connector 820 to
extend outwardly from the groove to the opposite lateral side portion 824.
Groove 812 has angled walls adjacent a mouth of the groove which narrow
inwardly and which allow side portion 824 to be directed inwardly into the
groove 812. Inner angled walls 814 within groove 812 then widen inwardly to
create angled walls which serve to contact and hinder removal of the circular
side portions of connector 820.
[0063] Referring now to Figures 9A and 9B, there is shown a further
form of connector 920, having a reduced number of teeth 924 relative to
connector 120. Further, connector 920 is of a reduced lateral width.
Connector 920 may be used for grooves 112 of a lesser depth because of the
reduced lateral width of connector 920. In Figure 9B, connector 920 is shown
having about an 80 degree angle between the (horizontal) central portion of
connector 920 and a centrally directed face of projections 924. Connector
920 is also shown as having an angle of about 77 degrees between the
outward face of projections 924 and the vertical. This may be alternatively
viewed as being 13 degrees from the horizontal central portion of connector
920. These angles are presently preferred but some variation may be
permitted, for example in the order of plus or minus 5 degrees.
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[0064] The angular orientation of the outward and centrally directed of
projections 924 are also applicable to the angled projections 124 of the
embodiment as shown in Figures 3 and 4. The main difference between
connector 920 and connector 120 is that connector 920 has fewer angled
projections 924. Otherwise, connectors 120 and 920 operate in a similar
manner.
[0065] Referring now to Figure 10, there is shown a further alternative
connector 1020, which combines the functions of spacer member 140 and
connector 920. Connector 1020 is generally cross shaped (like a plus sign)
but has angled projections 1024 projecting outwardly from the upper and
lower faces of connector 1020. These angled projections 102, when inserted
into grooves 112 at the corners of tiles 110, grip the interior walls of
grooves
112 to provide a form of retention means in a similar manner to connectors
120. Like spacer member 140, connector 1020 has four concave vertices
1044 for engaging fihe internal corner vertex of grooves 112 on adjacently
positioned tiles 110. Wings 1022 extend partially along the grooves 112 of
the side of each tile 110 to assist in alignment of the tiles 110 relative to
each
other, similar to the alignment and spacing function of the wings 144 of
spacer
member 140.
[0066] Figure 10A shows connector 1020 in plan view while Figure 10B
shows connector 1020 in partial side cross section, taken along line-B-B. The
width of wings 1022 as indicated by dimension Q in Figure 10A, while the
depth of wings 1022 (i.e. the amount by which they extend along the side of
each tile 110) is indicated by dimension R. The width of the central portion
of
each wing 1022 between angled projections 1024 is given by dimension P.
Connector 1020 is laterally, longitudinally and diagonally symmetrical.
[0067] Embodiments of the invention relating to the second main
aspect will now be described, with reference to Figures 11A, 11 B, and 12.
Figures 11A and 11 B show front and perspective views of a plank 1100 for
use in flooring applications. Plank 1100 is ideally suited to use in
circumstances where it is designed to limit the transmission of noise from one
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level of a multi-level building to the level below, while providing a flooring
that
resembles normal hardwood flooring and which is not unduly thick or bulky.
[0068] Planks 1100 have a groove 1112 and a tongue 1114 for
interlocking a number of planks 1100 to provide flooring across a substantial
area. Planks 1100 have a top veneer layer 1120 resembling a normal
hardwood plank and a substrate 1110 bonded to veneer layer 1120 by an
adhesive 1130.
[0069] Substrate 1110 has a thickness Z of at least 3/8" in order to
provide the desired level of sound attenuation of at least 60 decibels. The
thickness X of plank 1100 is preferably about 1/2", with the thickness Y of
the
veneer layer 1120 being about 1/8". A thickness Z of about 3/8" of substrate
1110 has been found to provide sound attenuation of about 61.5 decibels
based on the proportions of polyethylene and sawdust in substrate 1110
described below. A thicker substrate layer 1110 may be provided for even
greater sound attenuation.
(0070] Substrate 1110 is formed primarily of polyethylene and sawdust.
While good results have been obtained using only polyethylene and sawdust,
where the sawdust comprises 30% to 35% by volume of the substrate,
substrate 1110 may comprise small amounts of other materials if they are
suitable for enhancing the properties of substrate 1110 (and as long as they
do not detract from the properties of the substrate 1110).
[0071] It has been found that a proportion of 32% sawdust by volume is
optimal for substrate 1110. The resulting properties of substrate 1110 provide
good sound insulation while permitting substrate 1110 to be milled as if it
were
a solid wood plank and also providing a good bonding strength between
veneer layer 1120 and substrate 1110. Pure polyethylene is difficult to bond
with a hardwood veneer layer in a lasting fashion. Attempts were made to
bond a polyethylene substrate with a wood veneer layer using a number of
different adhesives. It was found that, once sawdust was added to the
polyethylene before curing it, the bonding characteristics of substrate 1110
improved substantially.
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[0072] Referring also to Figure 12, a manufacturing method 1200 for
manufacturing planks 1100 is described. Firstly, in order to form the
substrate
1110, polyethylene material is heated to its melting point, at step 1210.
Preferably, the polyethylene material is recycled polyethylene. At step 1220,
sawdust is added to the liquid polyethylene and mixed in evenly until the
mixture is sufficient to provide sawdust at a level of 32% by volume of the
solid substrate 1110.
[0073] At step 1230, the polyethylene and sawdust mixture is cooled
(or otherwise cured) and formed into sheets of solid material. Wood veneer is
then adhered to the sheets of substrate material to formed unmachined
panels at step 1240. The adhesion of the wood veneer layer to the substrate
may be done by a suitable adhesive, such as a polyvinyl acetate (PVA) glue
or other non-toxic, stable adhesive.
[0074] At step 1250, the panels are milled to a predetermined plank
size and the tongue and groove is formed in each plank using standard
machinery. At step 1260, the wood veneer layer on each plank is finished in
order to provide a suitable walking surface for flooring.
[0075] Embodiments of the invention relating to the third main aspect
will now be described with reference to Figures 13 to 15.
[0076] Figure 13 shows two wood planks 1300 placed laterally side-by-
side in an orientation common for flooring planks. Planks 1300 each have a
tongue 1314 and a groove 1312 for mating with an adjacent plank 1300.
Each plank 1300 has a body 1310 formed of a number of longitudinally
elongate wood pieces 1305. These wood pieces 1305 are recycled wood
offcuts from a milling operation where large wooden planks are cut down to a
predetermined size. The offcuts generated from this milling process are often
long, thin pieces of wood which can be reused. The offcuts are substantially
rectangular in cross-section. Planks 1300 are thus formed of reused
hardwood and are finished for use as hardwood flooring so as to have a
finished walking surface 1350 on the top face of the planks 1300.
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[0077] Figure 14 shows a plank 1400 identical to planks 1300, except
for the addition of shallow longitudinal grooves 1460 on an underside of plank
1400. These shallow longitudinal grooves 1460 are provided for stress relief
of plank 1400 and are preferably about 2mm to 4mm deep and 6mm to 10
mm wide. Plank 1400 has a finished walking surface 1450 on its top surface
and has a tongue 1414 and a groove 1412 for use in fitting the planks
together in normal flooring applications. Plank 1400, like planks 1300, is
formed a number of long, thin wood pieces 1405 of rectangular cross-section.
[0078] Figure 15 illustrates a method 1500 of manufacturing either of
wood planks 1300 or 1400. Method 1500 starts by milling wood to produce
offcuts of a predetermined thickness at step 1505. This can be done by
placing extra cutting blades at a certain distance outside the normal cutting
blades such that, for example, an offcut of 3/4" thickness can be obtained. At
step 1510, the offcuts are collected and cut to an appropriate longitudinal
length to be formed into a plank 1300 or 1400 of the desired length.
[0079] At step 1515, adhesive is applied to the offcuts on one side, for
example, at the top. At step 1520, the offcuts are each rotated by about 90
degrees and butted together to form a plank. The plank is then smoothed
with a planer at step 1525 and is pressed in a hot press, at step 1530. The
hot press presses the plank from the top and the bottom and the plank is also
pressed from its lateral sides while it is under vertical pressure in the hot
press.
[0080] At step 1535, the plank is trimmed and smoothed and the
tongue and groove is formed on opposite lateral sides. The stress relief
grooves are formed on the underside of the plank at step 1540, if plank 1400
is being made. Otherwise, step 1540 is skipped if plank 1300 is being made.
Finally, the top surface of plank 1300 or 1400 is finished as a walking
surface
at step 1545.
[0081] While embodiments of aspects of the invention have been
described and shown in the drawings, it is to be understood that these
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embodiments are presented by way of example only, without limitation to the
principles of the described aspects of the invention.
