Note: Descriptions are shown in the official language in which they were submitted.
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WOOD BOARD INCORPORATING EMBEDDED SOUND ATTENUATING ELEMENTS
AND STIFFENING ELEMENTS
FIELD OF THE INVENTION
This invention relates generally to boards used in the installation of
flooring and ceiling.
In particular, the present invention is directed to a board that incorporates
embedded sound
attenuating elements and stiffening elements to create a sound resistant floor
and ceiling
structure using only one layer of the boards.
BACKGROUND OF THE INVENTION
The log cabin and post and beam building industry traditionally matches the
ceiling
materials to that of the softwood walls of the room. Tongue and groove
softwood boards are laid
across the post and beam structure. The softwood-ceiling boards typically have
a chamfer on
each edge to help aesthetically offset any minor variations where the boards
meet. If the boards
are for a first level ceiling, they may also act as the flooring for the
second level of rooms if they
have sufficient thickness. However, many homeowners would prefer a hardwood
floor as it is
more durable than softwood and the hardwood can add an aesthetically appealing
visual offset to
all of the surrounding softwood making up the walls and ceiling. Currently to
install a hardwood
floor in a post and beam building requires that the builder lay down a second
layer of flooring
made of hardwood on top of the softwood flooring already in place for the
lower level ceiling.
Laying down a second layer of flooring made of hardwood adds considerably to
materials cost
and labor. These costs may be more than fifty percent of the overall
flooring/ceiling costs.
Furthermore, sound transmission between the first and second levels of a
building is a concern.
Solid wood boards do not offer a high level of sound resistance with respect
to both impact and
airborne sounds. To mitigate this problem a sound attenuating layer is usually
placed between
the ceiling boards and the floor boards. This additional step of incorporating
a sound attenuating
layer further increases the overall cost of installing the flooring/ceiling
system. The prior art
offers no simple and cost effective alternatives to this multi-step process
for creating a sound
resistant hardwood-floor / softwood-ceiling between two levels of a building.
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SUMMARY OF THE INVENTION
One aspect of the present invention is directed to a board comprising a wood
structure
having a first surface, a second surface, a first lateral edge, a second
lateral edge and opposing
ends. Sound attenuating elements are embedded within the wood structure.
Stiffening elements
are positioned within the wood structure to coincide with the location of
floor joists to which the
board will be secured.
Another aspect is directed to a method of fabricating a board comprising the
steps of
providing a first wood layer having a first wood surface, a second wood
surface, a first wood
lateral edge, a second wood lateral edge and opposing wood ends. Milling the
first wood layer to
create hollow regions and then embedding sound attenuating elements in the
hollow regions.
Still another aspect is directed to a method of fabricating a board comprising
the steps of
providing a first wood layer having a first wood surface, a second wood layer
having a second
wood surface, sound attenuating elements and stiffening elements. The method
includes coating
a portion of the sound attenuating elements and stiffening elements with
adhesive and laying a
matrix of the adhesively coated sound attenuating elements and stiffening
elements on the first
surface of the first wood layer. The method further includes positioning the
second wood layer
on top of the matrix and bonding the first wood layer, stiffening elements,
the sound attenuating
elements and the second wood layer together to form the board.
Yet another aspect is directed to a structure comprising a ceiling/floor
formed from floor
joists and a single set of adjacent boards. Each of the adjacent boards
includes embedded sound
attenuating elements and stiffening elements, wherein the stiffening elements
are positioned to
coincide with the location of the floor joist to which the board is secured.
Still yet another aspect is directed to a method of fabricating a
ceiling/floor comprising
the steps of providing floor joists and a set of boards. Each board includes
embedded sound
attenuating elements and stiffening elements that are positioned to coincide
with the location of
the floor joists. The method then includes laying the set of boards adjacent
to each other on the
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floor joists and securing the stiffening elements of each board to the floor
joist as each board is
laid.
BRIEF DESCRIPTION OF DRAWINGS
The foregoing and other aspects and advantages of the invention will be
apparent from
the following detailed description of the invention, as illustrated in the
accompanying drawings,
in which:
FIG. 1 is a perspective view of a ceiling/floor structure in accordance with
the present
invention showing boards incorporating embedded sound attenuating elements and
stiffening
elements, the stiffening elements are positioned to coincide with the location
of floor joist to
which the boards are secured;
FIG. 2a is a sectional, plan view of a board according to this inventions
showing sound
attenuating elements and stiffening elements, and their relationship to the
floor joists;
FIG. 2b is a sectional, side view of the board in FIG. 2a showing sound
attenuating
elements and stiffening elements, and their relationship to the floor joists;
FIG. 3 is a perspective view of a single board showing embedded sound
attenuating
elements, stiffening elements, tongue, groove and chamfers;
FIG. 4a is a first wood layer used in a first method of fabricating a board in
accordance
with the present invention;
FIG. 4b is the first wood layer in FIG. 4a now milled from a first wood
surface to create
hollow regions and stiffening elements;
FIG. 4c is the first wood layer in FIG. 4b now having the hollow regions
filled with
sound attenuating elements;
FIG. 4d is the first wood layer in FIG. 4c now having a second wood layer
bonded to the
first wood layer;
FIG. 5a is a first wood layer used in a second method of fabricating a board
in accordance
with the present invention;
FIG. 5b is the first wood layer in FIG. 5a now milled to create hollow
regions, transverse
stiffening elements and lateral stiffening elements;
FIG. 5c is the first wood layer in FIG. 5b now having the hollow regions
filled with
sound attenuating elements;
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FIG. 5d is the first wood layer in FIG. 5c now having a second wood layer
bonded to the
first wood layer;
FIG. 6a is a first wood layer used in a third method of fabricating a board in
accordance
with the present invention;
FIG. 6b is the first wood layer in FIG. 6a now milled to create hollow regions
and
transverse stiffening elements;
FIG. 6c is the first wood layer in FIG. 6b now having the hollow regions
filled with
sound attenuating elements and lateral stiffening elements;
FIG. 6d is the first wood layer in FIG. 6c now having a second wood layer
bonded to the
first wood layer;
FIG. 7a is a first wood layer used in a fourth method of fabricating a board
in accordance
with the present invention;
FIG. 7b shows a matrix of stiffening elements and sound attenuating elements
laid upon
the first wood layer in FIG. 7a;
FIG. 7c shows a second wood layer bonded to the matrix in FIG. 7b;
FIG. 8a is a first wood layer used in a fifth method of fabricating a board in
accordance
with the present invention;
FIG. 8b is the first wood layer in FIG. 8a now milled from a lateral wood edge
to create
hollow regions and stiffening elements;
FIG. 8c is the first wood layer in FIG. 8b now having the hollow regions
filled with
sound attenuating elements;
FIG. 8d is an alternative structure to that shown in FIG. 8c where in addition
to sound
attenuating element, lateral stiffening elements fill the hollow regions along
the lateral edges of
the wood structure;
FIG. 9a is a transverse, sectional view through a wood board showing a first
wood layer,
a second wood layer, embedded sound attenuating element, lateral stiffening
elements, and a
single tongue and groove structure;
FIG. 9b is a transverse, sectional view through a wood board showing a first
wood layer,
a second wood layer, embedded sound attenuating element, lateral stiffening
elements, and a
double tongue and groove structure;
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FIG 10 is a perspective, sectional view of a hardwood-floor / softwood-ceiling
structure
according to the present invention illustrating a single set of adjacent
boards comprising
embedded sound attenuating elements and stiffening elements, the stiffening
elements coincide
with the location of floor joist to which the boards are secured.
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1-9 illustrate board 20 according to the present invention. Board 20 can
be in the
range of 2-12 inches wide and 2-20 feet long, but is typically about 6-inches
wide and 8-feet
long. Board 20 comprises a wood structure 22 having first surface 24a, second
surface 24b, first
lateral edge 28a, second lateral edge 28b and opposing ends 30. Sound
attenuating elements 34
are embedded within wood structure 22. Each sound attenuating element 34 has a
first side 59
and a second side 61. Sound attenuating element 34 may be any sound
attenuating material, but
preferably a material such as CELOTEX fiber board or foam such as SPRAYFOAMe.
Both of
these materials provide structural rigidity yet have high sound attenuation
qualities. However,
because the structural rigidity of these sound attenuating materials is not as
good as that of
natural wood, stiffening elements 36 are added to the board 20 to help
strengthen the board.
Stiffening elements 36 are positioned within wood structure 22 to coincide
with the location of
floor joists 38 to which the board 20 will be secured. Typically, the floor
joists 38 are spaced at
24-inches, 32-inches or 48-inches. Stiffening elements 36 are preferably
natural wood, but could
be a high-strength wood composite or other high-strength material. Together
sound attenuating
elements 34 and stiffening elements 36 make up a matrix within board 20. Sound
attenuation
elements 34 are preferably a continuous layer of sound attenuating material
that spans between
stiffening elements 36. When embedded within wood structure 22, sound
attenuating elements
34 are a solid sound attenuating material. Stiffening elements 36 provide
strength to board 20 so
that the board is less likely to flex under an applied load as well as provide
stiff regions that can
be secured to floor joists 38. Stiffening elements 36 may take on any shape
and orientation
within the matrix so long as they coincide with floor joists 38. The location
where stiffening
elements 36 and floor joists 38 coincide is where securing elements 39 such as
nails, screws, etc.
secure board 20 to the floor joists. FIG.1 illustrates ceiling/floor structure
37 where adjacent
boards 20 are secured by securing elements 39 to floor joist 38.
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Several methods may be used to manufacture board 20 as illustrated in FIGS. 4-
8. A first
method is illustrated in FIGS. 4a-d. In this first method a first wood layer
40 is provided as
illustrated in FIG. 4a. First wood layer 40 has a first wood surface 42a, a
second wood surface
42b, a first wood lateral edge 46a, a second wood lateral edge 46b, and
opposing wood ends 50.
First wood layer 40 can be a single piece of lumber or a single piece of
graded, finger-jointed
lumber. First wood layer 40 is milled from the first wood surface 42a to
create hollow regions 52
in the first wood layer. During this milling step, stiffening elements 36 are
created as un-milled
regions of the first wood layer 40 that coincide with the location of floor
joists 38 to which board
20 will be secured. In FIG. 4b stiffening elements 36 are shown as transverse
stiffening elements
54. Transverse stiffening elements 54 lay across board 20 substantially
perpendicular to both first
and second wood lateral edges, 46a and 46b, respectively. Transverse
stiffening elements 54 are
substantially the same width as floor joist 38 and when used in constructing a
floor/ceiling
structure coincide with the floor joist and lay substantially parallel to the
floor joist. First wood
layer 40, however, can be milled to have stiffening elements 36 that differ in
orientation and
shape from the transverse stiffening elements 54. In general stiffening
elements 36 will coincide
with floor joists 38 providing added rigidity to board 20 as well as stiff
sections through which to
secure the board to the floor joists. Hollow regions 52 are then embedded with
sound attenuating
elements 34 as illustrated in FIG. 4c. Sound attenuating elements 34 may be
fibers, foam or other
sound attenuating layer that has been cut to size. Sound attenuating elements
34 are coated on
one or more surfaces with an adhesive layer 56 and placed within hollow region
52. A second
wood layer 58 is then bonded to first wood layer 40 on first wood surface 42a
with adhesive
layer 56 as illustrated in FIG. 4d. Second wood layer 58 can be a single piece
of lumber or a
single piece of graded, finger-jointed lumber. Adhesive layer 56 is applied as
needed to any
surface of the wood layers or sound attenuating elements 34 to be joined.
Adhesive layer 56 may
be rolled or sprayed onto each layer. First wood layer 40 and second wood
layer 58, with
embedded sound attenuating elements 34 between them, is then press rolled or
clamp pressed to
create wood structure 22 incorporating the sound attenuating elements and
stiffening elements
36. Heating by radiation or RF heating may or may not be added into the
process depending on
the type of adhesive used. Adhesive layer 56 may be glue, an epoxy or other
similar wood-
bonding agent. Examples of commercially available wood bonding adhesives are
TITEBONDO-
50 and TITEBONDR-Regular, both aliphatic resin emulsion adhesives manufactured
by
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Franklin Adhesives. All wood in wood structure 22 is preferably kiln dried to
6-8% moisture.
Having low moisture content helps reduce warping in board 20.
For the method defined in FIGS. 4a-d, first wood layer 40 and second wood
layer 58 may
both be the same species of wood or different species of wood. For example in
a hardwood-
floor/softwood-ceiling board, first wood layer 40 is preferably softwood and
second wood layer
58 is preferably hardwood. Softwoods include species such as pine, spruce,
fir, white cedar, red
cedar and any other domestic or imported softwood. Hardwoods include species
such as oak,
maple, birch, ash, walnut, hickory, cherry, and any other domestic or imported
hardwood. When
first wood layer 40 and second wood layer 58 are single layers of natural
wood, each is a saw cut
layer rather than rotary peeled from the circumference of the log which is
known as veneer
fashion. Rotary peeled layers inherently have fractures from the peeling
process making them
undesirable for use in boards 20.
FIGS. 5a-d illustrate a second method of fabricating board 20 according to the
present
invention. In this second method the steps are the same as described in the
first method above
(FIG. 4a-d) except that during the milling step illustrated in FIG. 4b, the
milling is now modified
to produce a structure that has both transverse stiffening elements 54 and
lateral stiffening
elements 60 as illustrated in FIG. 5b. Lateral stiffening elements 60 lay
along the first wood
lateral edge 46a and second wood lateral edge 46b of first wood layer 40.
Lateral stiffening
elements 60 provide further strength and stiffening to board 20 as well as
provide for a wood
surface on all edges of the board. As shown in FIG. 5c, hollow regions 52 are
once again filled
with appropriately sized sound attenuating elements 34 in the same manner as
in the first
method. Then in FIG. 5d, second wood layer 58 (either of the same wood species
or different
wood species) is bonded to first wood layer 40 on first wood surface 42a with
adhesive layer 56,
again the same manner of bonding is used as in the first method.
FIGS. 6a-d illustrate a third method of fabricating board 20 according to the
present
invention. In this third method the steps are the same as described in the
first method above
(FIG. 4a-d) except that during the embedding step illustrated in FIG. 4c,
hollow regions 52 are
now filled with sound attenuating elements 34 on the interior and pieces of
wood along the first
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wood lateral edge 46a and second wood lateral edge 46b as illustrated in FIG.
6c. These pieces
of wood become lateral stiffening elements 60. Again, an adhesive layer 56 is
applied on each
appropriate surface of either the sound attenuating elements 34 or lateral
stiffening elements 60.
Then in FIG. 6d, second wood layer 58 (either of the same wood species or
different wood
species) is bonded to first wood layer 40 on first wood surface 42a with
adhesive layer 56, again
the same manner of bonding is used as in the first method.
FIGS. 7a-c illustrate a fourth method of fabricating board 20 according to the
present
invention. In this fourth method a first wood layer 40 is provided as in the
first method described
above. However, instead of milling the first wood layer, separate sound
attenuating elements 34
and stiffening elements (being at least one from the group including
transverse stiffening
elements 54 and lateral stiffening elements 60) are laid on first wood surface
42a of first wood
layer 40 to form a matrix as illustrated in FIG. 7b. The matrix may be any
combination of sound
attenuating elements 34 and stiffening elements 36. Each element of the matrix
is appropriately
coated with a layer of adhesive. During this laying step, stiffening elements
are positioned to
coincide with floor 38 joists to which board 20 will be secured. A second wood
layer 58, either
of the same species or different species of wood, is positioned on top of the
matrix and all
elements are bonded together as illustrated in FIG. 7c. Application of
adhesive layer 56 and
bonding of all the elements together follows the same manner of bonding as
described in the first
method.
FIGS. 8a-d illustrate a fifth method of fabricating board 20 according to the
present
invention. In this fifth method a first wood layer 40 is provided. First wood
layer 40 can be a
single piece of lumber, a piece of lumber having a softwood side and a
hardwood side, or a
single piece of graded, finger-jointed lumber. A milling step occurs as in the
first method,
however, during the milling step first wood layer 40 is milled from either or
both first wood
lateral edge 46a or the second wood lateral edge 46b to provide hollow region
52 as shown in
FIG. 8b. Milling first wood layer 40 in this manner creates transverse
stiffening elements 54 that
are an integral part of the first wood layer. Each hollow region 52 has a
first hollow surface 55
and a second hollow surface 57. Hollow regions 52 can then be filled with
precut sound
attenuating elements 34 or filled with sound attenuating foam as illustrated
in FIG. 8c. Each
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sound attenuating element 34 has a first side 59 and a second side 61. All
first sides 59 of sound
attenuating elements 34 are covered completely by first wood surface 42a of
wood layer 40. All
second sides 61 of sound attenuating elements 34 are covered completely by
second wood
surface 42b of wood layer 40. If it is desired to have wood on all surfaces of
the finished board
20, lateral stiffening elements 60 made of wood may be incorporated into each
hollow region 52
along first wood lateral edge 46a and second wood lateral edge 46b as
illustrated in FIG. 8d.
Once wood structures 22 have been formed using any of the methods described
above,
board 20 may be further shaped to provide a tongue 62 on first lateral edge
28a and a groove 64
on second lateral edge 28b of the board as illustrated in FIG. 9a.
Alternatively, a double tongue
and groove structure may be provided as shown in FIG. 9b. The tongue(s) 62 of
a first board is
shaped to fit in groove(s) 64 of a second board so that when boards 20 are
laid adjacent to each
other the tongue in groove structure provides a tight interlocking seam
between the boards. The
double tongue and groove structure can provide better interlocking between
thick boards. Board
20 may also have a tongue on one end 30 and a groove on the other opposing end
for creating a
tongue in groove interlocking seam when the boards are laid end-to-end. Either
the first surface
24a or second surface 24b may be further provided with first chamfer 66a and
second chamfer
66b along first and second lateral edges, 28a and 28b, respectively. Chamfers
66a and 66b are
typically 1/8-inch to 1/2-inch and help aesthetically offset any minor
variations where boards 20
meet when the boards are laid adjacent to each other. A micro-bevel of less
than 1/16-inch may
also be provided to first lateral edge 24a and second edge 24b on the surface
opposite the
chamfered surface. Once shaped to spec board 20 may have either first surface
24a or second
surface 24b sanded. A finishing layer 68 may be applied to either or both
first surface 24a or
second surface 24b. Finishing layer 68 protects the luster and beauty of the
wood. Finishing layer
68 may include at least one from the group including a stain, polyurethane,
varnish or a mixture
thereof
When boards 20 have a softwood side 71 and hardwood side 73 they become boards
20a
and are preferably used between a first level 70 and second level 72 of a
building to provide a
softwood-ceiling / hardwood-floor structure 74. Softwood-ceiling / hardwood-
floor structure 74,
illustrated in FIG. 10, is formed from a single set of adjacent boards 20a.
When fabricating
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structure 74, carrying beams are first provided to span walls 76 between first
level 70 and second
level 72 within a building. First level 70 and second level 72 may be the
basement and ground
level, ground level and second story, second story and third story, etc.
Carrying beams are
usually softwood and match the wood used to construct the exterior walls of
the home. Carrying
beams include floor joists 38. If engineering calls for it, carrying beams may
also include a main
carrying beam 78. Floor joists 38 generally lay at right angles to main
carrying beam 78. Main
carrying beam 78 requires the support of post 80.
To construct the softwood-ceiling / hardwood-floor structure 74, the user
usually starts on
one side of the room. A first board 20a having embedded sound attenuating
elements 34 and
stiffening elements 36 is placed with softwood side facing downwards, toward
floor joist 38 and
secured to the floor joists. Each board 20a is secured by a securing element
39. For example, one
may hammer nails through tongue 62 at the location of the stiffening element
36. The next board
20a is then laid adjacent to the first board with groove 64 of the second
board fitted into tongue
62 of the first board. This second board 20a is then secured to floor joists
38. The process of
laying and securing boards 20a adjacent to each other is carried out until the
whole ceiling/floor
structure 74 is complete. Using this process a hardwood-floor and softwood-
ceiling structure 74
can be fabricated using only a single layer of boards 20a in one pass. This
provides a significant
time/cost savings over the three-step process of laying a softwood ceiling,
laying a sound
attenuating layer and then subsequently laying a hardwood floor. A softwood-
ceiling / softwood-
floor structure may also be fabricated in the manner described above by
substituting boards
having softwood on both sides with embedded sound attenuating elements 34 and
stiffening
elements 36. Similarly a hard-wood ceiling / hardwood-floor structure many be
fabricated in the
manner described above by substituting boards having hardwood on both sides
with embedded
sound attenuating elements 34 and stiffening elements 36.
Tongue 62 and groove 64 must be at the same height on each edge on board 20 so
that
they line up when the boards are placed adjacent and edge-to-edge with each
other. Tongue 62
and groove 64 may span a considerable thickness of board 20 so as to include
part of first layer
40 and second layer 58. Because first layer 40 and second layer 58 are thick
layers, tongue 62
and groove 64 may lie within just one of either layer.
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Boards 20 may also incorporate a veneer or laminate. Veneer consists of a thin
layer of
one type of wood bonded on top of a thick base board of a different type of
wood, where the
veneer is merely for changing the appearance of one side of the board. Veneer
is usually a layer
rotary peeled from a log and less than 1/8-inch thick. A veneer may be bonded
to either side of
board 20. A laminate is usually a layer less than 1/16-inch thick. A laminate
may be bonded to
either side of board 20.
When boards 20 have wood on all surfaces it may not be obvious where the
location of
stiffening elements are, therefore the boards may incorporate alignment
markings 82 on the
edges of board to show the location of the stiffening elements within the
board. These alignment
markings 82 may be a notch, ink mark or other type of mark to aid where one
can cut board 20
and also where one can secure the board to the floor joist 38
The invention is not limited to the embodiments represented and described
above but
includes all variants notably those concerning the types of sound attenuating
materials used, the
shape and orientation of stiffening elements, the exact ratio of the thickness
of the first wood
layer to the second wood layer, the types of wood species making up the wood
layers and the
overall thickness of the bonded wood layers. The scope of the claims should
not be limited by
the preferred embodiments set forth in the examples, but should be given the
broadest
interpretation consistent with the description as a whole.
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