Note: Descriptions are shown in the official language in which they were submitted.
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STAIR TREAD OVERLAY AND MANUFACTURING PROCESS
BACKGROUND OF THE INVENTION
1. Field Of The Invention
[0001] This invention relates generally to the field of staircase repair
and restoration
and relates more particularly to hardwood overlays for covering an existing
composite or
solid wood staircase, a method of installing the same, and the manufacturing
process
for the tread and nose of a staircase overlay.
2. Description Of The Related Art
[0002] Conventional staircases of the type found in many residential
buildings are
commonly fabricated from raw, construction grade materials, such as plywood,
fiberboard or various other composites, and are covered with flooring
materials such as
carpeting to provide an attractive and comfortable exterior surface. It is
also relatively
common for residential staircases to be fabricated from solid hardwood, such
as oak,
walnut, or cherry. Hardwood staircases are generally more desirable than
carpeted
composite staircases and are more expensive to construct due to the higher
cost of the
materials involved.
[0003] In the case of carpeted staircases, it is sometimes desirable to
upgrade the
staircase to a solid hardwood staircase for aesthetic reasons, such as when
the seller of
a home wishes to make the home more attractive to potential buyers, even when
the
original carpeted staircase is in good condition. In the case of hardwood
staircases, the
accumulation of surface wear over the course of time can make replacement of
the
staircase desirable, and sometimes even necessary, for aesthetic and
functional
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reasons. In either case, replacing an existing staircase with a new, solid
hardwood
staircase typically requires extensive demolition and can sometimes be
prohibitively
expensive.
[0004] It would therefore be advantageous to have a means for achieving the
appearance, durability, and longevity of a brand new, solid hardwood staircase
without
having to demolish an existing hardwood or carpeted composite staircase. It
would
further be advantageous to have such a means to manufacture and install such
overlays that are affordable and that can be implemented quickly and easily.
SUMMARY OF THE INVENTION
[0005] In accordance with the present invention, there is provided a stair
tread
overlay and a riser overlay that are made from solid wood and that are milled
and cut to
fit over a conventional, exposed wooden stair having a generally rounded nose
like
those found in most residential general construction staircases and
prefabricated
staircases. The tread overlay and riser overlay can cover a conventional
wooden stair
tread and riser completely from end to end (stringer to stringer) to hide a
construction
grade stair tread and riser (e.g., a stair tread and a riser that are made
from plywood or
another composite and that are typically covered with flooring material, such
as
carpeting) or an unsalvageable hardwood stair tread and riser to present an
attractive,
solid wood surface that is finishable. The tread overlay and riser overlay can
also be
used to cover a tread and riser only at the longitudinal ends of the tread and
riser,
against the abutting stringers of the staircase, to provide a finished
hardwood surface at
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each end of the tread and riser in order to facilitate the installation of a
carpet type
runner in the middle of the staircase.
[0006] The profile of the tread overlay is preferably J-shaped and conforms
to the
shape of a conventional wooden stair tread profile having a rounded front
edge. The
overlay is formed with a length and a depth that are greater than that of a
standard
tread for allowing the overlay to be trimmed to size for accommodating a
variety of
standard and non-standard applications. The overlay can be milled and/or
carved to
allow fitment over multiple tread thicknesses. The overlay is affixed to an
existing tread
by using any conventional wood-to-wood adhesive, although it is contemplated
that any
other fastener for mounting the overlay to an existing tread, such as nails or
screws, can
also be used.
[0007] The tread overlay and riser overlay are preferably each formed of a
single
piece of solid hardwood material with an exterior surface that is finishable
for accepting
a desired stain color and/or finish coat. It is contemplated, however, that
the overlay can
be formed of multiple pieces of wood that are fit together. The overlays can
be finished
prior to installation (prefinished) or finished after installation (site
finished).
[0008] The invention thus provides an alternative means of converting
wooden
staircases made from construction grade materials (solid or composite) or
unsalvageable hardwood staircases into substantially new-looking solid
hardwood
staircases. The invention simplifies the task of conversion by eliminating the
need to
demolish, modify, and/or reconstruct the existing staircase as is typical with
current
methods for achieving hardwood conversion. Applying the tread overlays and
riser
overlays of the present invention to an existing staircase provides the
staircase with an =
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exterior surface that is consistent with most characteristics of a
conventional solid
hardwood staircase. The overlays achieve the beauty, durability and longevity
that solid
wood provides. Because the overlays are made of solid hardwood and have a
substantial thickness, they can are sandable and refinishable.
[0009] The present invention also provides for one or more manufacturing
processes
of a stair tread overlay and a riser overlay that are made from solid wood or
a wood
based material. An exemplary embodiment of the manufacturing process comprises
the
milling of wood blanks, including the milling of the tread overlay nose, and
cutting the
solid wood to fit over a conventional, exposed wooden stair having a generally
rounded
nose like those found in most residential and prefabricated staircases.
[0010] The present invention provides for one or more manufacturing
processes of a
stair tread overlay and a riser overlay including stair tread and riser
overlays made from
solid wood or a wood based material. An exemplary embodiment of the
manufacturing
process comprises the milling of wood blanks, including the milling of the
tread overlay
nose, and cutting the overlays to fit over a conventional, exposed wooden
stair having a
generally rounded nose like those found in most residential and prefabricated
staircases. An additional exemplary embodiment of the manufacturing process
comprises forming the tread overlay with a concave inner surface nose using
pressure
molding of a wood based material including pressure forming, pressure molding,
and
extrusion using a mold or convex nose mold or extrusion through a mold having
a
profile with a nose which forms a concave inner surface.
[0011] The present invention provides a method of manufacturing a solid
wood stair
tread overlay, said method comprising the steps of: (a) cutting raw material
into at least
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one board of a desired thickness; (b) cutting the board to a desired length;
(c)
machining the board edges; (d) grain matching at least two boards; (e)
adhering the
edges of the two boards together to create a tread body; (f) cutting raw
material into at
least one nose block; (g) cutting the nose block to desired length; (h) grain
matching the
nose block with the tread body; (i) adhering the nose block to the tread body
creating a
tread blank; (j) machining the inside of the nose block to create a concave
shape; (k)
machining the outside of the nose block to create an outside shape of nose.
Further,
the adhering of the edges may be done using glue and pressure. The adhering of
the
nose block may be done using glue and pressure. The machining of the tread
overlays
may be done in one or more passes. The nose block may be adhered to the bottom
of
the tread body or the edge of the tread body. The tread blank may be secured
to a
machining table using suction or mechanical means or fixtures. The method may
make
use of a router to form the concave inner surface of the nose. The nose may be
formed
before being attached to the tread body. The present invention also embodies a
stair
tread overlay manufactured according to the method described above.
[0012]
The present invention also provides a method of manufacturing a solid wood
stair tread overlay, said method comprising the steps of: (a) cutting raw
material into at
least one board of a desired thickness; (b) cutting the board to a desired
length; (c)
machining the board edges; (d) grain matching at least two boards; (e)
adhering the
edges of the two boards together to create a tread body; (f) cutting raw
material into at
least one nose block; (g) cutting the nose block to desired length; (h) grain
matching the
nose block with the tread body; (i) adhering the nose block to the tread body
creating a
tread blank; and (j) forming a concave shape on the inner surface of the nose
block.
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Further, the adhering of the edges may be done using glue and pressure. The
adhering
of the nose block may be done using glue and pressure. The forming of the
concave
shape on the inner surface of the nose block may be made by milling the nose
block. A
stair tread overlay manufactured according to the method described above.
[0013] The present invention also provides a method of manufacturing a
stair tread
overlay, said method comprising the steps of: (a) cutting raw material into at
least one
board of a desired thickness; (b) cutting the board to a desired length; (c)
machining the
board edges; (d) grain matching at least two boards; (e) adhering the edges of
the two
boards together to create a tread body; and (f) forming a nose on the end of
the tread
body wherein the nose has a concave inner surface. The inner concave surface
of the
nose may be formed by milling. The adhering of the edges in may be done using
glue
and pressure. The adhering of the nose block may be done using glue and
pressure. A
stair tread overlay manufactured according to the method described above.
[0014] The present invention also provides a method of manufacturing a
stair tread
overlay nose, the method comprising the steps of: (a) cutting raw material
into at least
one nose block; (b) cutting the nose block to a desired length; (c) machining
the inside
of the nose block to create a concave shape; (d) machining the outside of the
nose
block to create an outside shape. A stair tread overlay manufactured according
to the
method described above.
[0015] The present invention also provides a method of manufacturing a
stair tread
overlay, said method comprising the steps of: (a) forming a stair tread body
from wood
material, wherein the stair tread has a front edge; (b) forming a nose on the
front edge,
wherein the nose has a concave inner surface. Forming the nose may include the
step
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of adhering a nose block to a stair tread body and milling the nose block to
the concave
inner surface. Forming the nose may include the step of adhering a nose block
which
has already been milled to have a concave inner surface to the stair tread
body.
Forming the nose may include the step of pressure molding where the tread
and/or
nose are a wood fiber and epoxy mix. Forming the nose may include the step of
pressure molding the front edge of the tread body around a convex mold.
Forming the
nose may include the step of bending the front edge of the tread body around a
convex
mold. Forming the tread overlay may include the step of using pressure
extrusion
through an extrusion mold having a profile with a nose having a concave inner
surface.
A stair tread overlay manufactured according to the method described above.
[0016] These and other objects, features, and/or advantages may accrue from
various aspects of embodiments of the present invention, as described in more
detail
below.
[0017] These and other objects, features, and/or advantages may accrue from
various aspects of embodiments of the present invention, as described in more
detail
below.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0018] FIG. 1 is a perspective exploded view in section illustrating the
preferred
embodiment of the present invention.
[0019] FIG. 2 is a side view illustrating the tread overlay of the
preferred embodiment
of the present invention shown in FIG. 1.
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[0020] FIG. 3 is a side view in section illustrating the preferred
embodiment of the
present invention.
[0021] FIG. 4 is a perspective view illustrating a first alternative
embodiment of the
present invention.
[0022] FIG. 5 is a perspective exploded view in section illustrating a
second
alternative embodiment of the present invention.
[0023] FIG. 6 illustrates a flowchart depicting the manufacturing process
for the tread
of a solid wood staircase overlay.
[0024] FIG. 7 illustrates a flowchart depicting the manufacturing process
for the nose
of a solid wood staircase overlay.
[0025] FIG. 8 illustrates the continuation of the manufacturing process
where the
tread and the nose are attached to create the finished solid wood staircase
overlay
product.
[0026] In describing the preferred embodiment of the invention which is
illustrated in
the drawings, specific terminology will be resorted to for the sake of
clarity. However, it
is not intended that the invention be limited to the specific term so selected
and it is to
be understood that each specific term includes all technical equivalents which
operate
in a similar manner to accomplish a similar purpose. For example, the word
connected
or terms similar thereto are often used. They are not limited to direct
connection, but
include connection through other elements where such connection is recognized
as
being equivalent by those skilled in the art.
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DETAILED DESCRIPTION OF THE INVENTION
[0027] Referring to FIGS. 1-3, a stair tread overlay 10 and a riser overlay
12 for
fitting over the treads 14 and risers 16 of a prefabricated composite or solid
wood
staircase 18 are shown. Both the tread overlay 10 and the riser overlay 12 are
fabricated from solid oak, although it is contemplated that the tread overlay
10 and the
riser overlay 12 can alternatively be fabricated from the wood of any non-
monocot
angiosperm tree (i.e., hardwood), including, but not limited to walnut, ash,
cherry, and
hickory. It is further contemplated that the tread overlay 10 and riser
overlay 12 can be
fabricated from the wood of any coniferous tree (i.e., softwood), including,
but not
limited to cedar, pine, and spruce, although hardwoods are generally preferred
over
softwoods for their superior durability.
[0028] The tread overlay 10 is preferably milled from a solid piece of
hardwood and
is defined by a planar tread portion 20 (see FIG. 2) and a rounded nose
portion 22,
although it is contemplated that the tread overlay 10 can be formed of two or
more
separate pieces of wood that are mounted to one another, such as with
conventional
fasteners or adhesives. For example, an equivalent tread overlay can be made
of a
separate planar panel and a curved piece that are glued together when
installed.
Referring to FIG. 2, the tread overlay has a J-shaped profile with a uniform
thickness of
3/8 inches, although it is contemplated that tread overlay 10 can have any
thickness in a
range of about 0.05 inches to about 1 inch. It is further contemplated that
the thickness
of the tread overlay 10 can be non-uniform, for example to accommodate an
underlying
obstruction.
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[0029] The nose portion 22 of the tread overlay has an interior height, h
of 1.5 inches
and an interior radius, r of 0.075 inches for fitting over the nosing of most
standard size
stair treads (as will be described in greater detail below), although it is
contemplated
that the interior height, h and interior radius, r of the tread overlay 10 can
be varied to
conform to the size and shape of any stair tread that is to be covered. It is
further
contemplated that the nose portion 22 of the tread overlay can have a variety
of other
profile shapes, such as rectangular or triangular, for conforming to an
existing stair tread
that is not rounded. Still further, it is contemplated that the nose portion
22 of the tread
overlay can have an interior profile shape that conforms to the nose shape of
a stair
tread to be covered but an exterior profile shape that is different than the
nose shape of
the stair tread to be covered. For example, it is contemplated that the nose
portion 22 of
the tread overlay 10 can have a rounded interior profile shape for fitting
over the
rounded nose of an underlying stair tread and a square exterior profile shape
for
providing the underlying staircase with a new and different exterior shape.
Still further, it
is contemplated that voids can exist if the interior profile shape does not
precisely
conform to the exterior shape of the stair tread.
[0030] Referring to FIG. 1, the tread overlay 10 and a plurality of similar
tread
overlays 24 and 26 that are intended to cover the stair treads 14 of the same
existing
composite or unsalvageable solid wood staircase 18 are preferably fabricated
with a
uniform width and a uniform depth that are greater than the width and the
depth of the
stair treads 14 that are to be covered. The tread overlays 10, 24, and 26 can
therefore
be individually trimmed down to a necessary width and depth on-site, such as
with a
table saw or a circular saw. This allows precise custom fitting of the tread
overlays 10,
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24, and 26 for each of the individual stair treads 14 in the existing
staircase 18, some of
which may have been built with intended or unintended variances in size or
which may
have shifted or been repaired over time. For example, for covering most
standard size
stair treads having a width of 3.5 feet and a depth of 10 inches, the tread
overlays 10,
24, and 26 are preferably fabricated with a width of 4 feet and a depth of 12
inches.
Alternatively, it is contemplated that the treads 14 on the existing staircase
18 can be
individually measured and that each individual tread overlay 10, 24, and 26
can be
fabricated with dimensions matching a specific premeasured tread 14 to achieve
a
proper fit thereon.
[0031] Still referring to FIG. 1, the riser overlay 12 is an elongated
rectangular panel
that is preferably cut from a single piece of hardwood, although it is
contemplated that
the riser overlay 12 can be formed of two or more separate pieces of wood that
are
mounted to one another, such as with conventional fasteners or adhesives. The
riser
overlay 12 has a uniform thickness of 3/8 inches, although it is contemplated
that riser
overlay 12 can have any thickness in a range of about 0.05 inches to about 1
inch. It is
further contemplated that the thickness of the riser overlay 12 can be non-
uniform. Still
further, it is contemplated that the riser overlay 12 can have any shape other
than
rectangular, such as triangular or trapezoidal, for conforming to the shape of
a particular
riser that is to be covered.
[0032] As with the stair tread overlays 10, 24, and 26 described above, the
riser
overlay 10 and a plurality of similar riser overlays 32 and 34 that are
intended to cover
the risers 16 of the same existing staircase 18 are preferably fabricated with
a uniform
width and a uniform height that are greater than the width and the height of
the risers 16
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that are to be covered. The riser overlays 12, 32, and 34 can therefore be
individually
trimmed to a necessary width and height on-site, such as with a table saw or a
circular
saw, to allow precise custom fitting of the riser overlays 12, 32, and 34 for
each of the
individual risers 16 in the existing staircase 18, some of which may have been
built with
intended or unintended variances in size. For example, for covering most
standard size
stair risers having a width of 3.5 feet and a height of 7 inches, the riser
overlays 12, 32,
and 34 are preferably fabricated with a width of 4 feet and a height of 8
inches.
Alternatively, it is contemplated that the risers 16 on the existing staircase
18 can be
individually measured and that each individual riser overlay 12, 32, and 34
can be
fabricated with dimensions matching a specific premeasured riser 16 to achieve
a
proper fit thereon.
[0033] In order to install the tread overlays 10, 24, and 26 and the riser
overlays 12,
32, and 34 on an existing composite or unsalvageable hardwood staircase, such
as the
staircase 18 in FIG. 1, an installer first measures the width and depth of the
existing
staircase's treads 14 and the width and height of the existing staircase's
risers 16. If the
existing treads 14 and risers 16 are obviously of uniform size, the installer
will generally
only need to measure the tread and riser of a single stair, otherwise the
installer will
have to measure each tread and riser that differs in size.
[0034] Next, the tread overlays 10, 24, and 26 and the riser overlays 12,
32, and 34
of the present invention, which are fabricated with dimensions larger than
those of the
existing treads 14 and risers 16 (as described above), are cut down to the
measured
sizes of the existing treads 14 and risers 16 on-site. For example, the tread
overlays 10,
24, and 26 are cut longitudinally and laterally to reduce their depths and
widths,
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respectively, to appropriate sizes. Similarly, the riser overlays 12, 32, and
34 are cut
laterally to reduce their widths to appropriate sizes.
[0035] Finally, the cut tread overlays 10, 24, and 26 and cut riser
overlays 12, 32,
and 34 are firmly mounted to the treads 14 and risers 16 of the existing
staircase with
conventional wood-to-wood adhesive. Of course, it is contemplated that the
tread
overlays 10, 24, and 26 and riser overlays 12, 32, and 34 can be mounted to
the treads
14 and risers 16 using any other suitable means of affixation, such as with
conventional
fasteners or with other types of adhesives. The surfaces of the tread overlays
10, 24,
and 26 and riser overlays 12, 32, and 34 that face and engage the existing
treads 14
and risers 16 have a moderately rough texture for holding the adhesive to
achieve
proper adhesion. Such a surface texture can be achieved using any conventional
means, such as by sanding or by the milling and cutting processes used to
fabricate the
overlays 10, 24, 26, 12, 32, and 34. In some cases, it may be beneficial or
necessary to
sand or otherwise distress the exterior surfaces of the existing stair treads
14 and risers
16 before mounting the overlays 10, 24, 26, 12, 32, and 34 in order to provide
the
treads 14 and risers 16 with a surface that is sufficiently rough to hold the
adhesive.
[0036] Once installed, the tread overlays 10, 24, and 26 and riser overlays
12, 32,
and 34 cover substantially all of the exterior surfaces of the treads 14 and
risers 16 of
the underlying staircase from stringer 40 to stringer 42 (only the stringer 40
is shown in
FIGS. 1 and 3). The tread overlays 10, 24, and 26 and riser overlays 12, 32,
and 34
preferably have finishable exterior surfaces for accepting any desired stain
color and/or
finish coat, such as varnish or paint. It is contemplated that the overlays
10, 24, 26, 12,
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32, and 34 can be finished prior to installation (prefinished) or finished
after installation
(site finished) as will be appreciated by those skilled in the art of flooring
materials.
[0037] Referring to FIG. 4, a first alternative embodiment of the inventive
tread
overlay, indicated generally at 40, is contemplated for fitting over an "open-
ended" stair
tread. An "open-ended" stair tread is defined herein as a stair tread having a
first
longitudinal end that abuts a conventional stringer and an opposite
longitudinal end that
extends into open space (i.e., does not abut a stringer in the same way). An
open-
ended tread therefore has three exposed edges (i.e., a front edge, a partially
protruding
rear edge, and a longitudinal edge) which is to be contrasted with the "closed-
end" stair
treads 14 described above which only have one exposed edge (i.e., a front
edge).
[0038] The tread overlay 40 is similar to the tread overlay 10 described
above with a
first nose portion 42 extending from the front of the tread portion, but
additionally
includes a second, separate nose portion 44 adjoining the first nose portion
42 that
extends from a longitudinal end of the tread portion and a third, separate
nose portion
46 adjoining the second nose portion 44 that extends from the rear of the
tread portion.
When assembled together, the three nose portions 42-46 cover all three exposed
edges
of the underlying open-ended tread. It is contemplated that the tread overlay
40 can
alternatively be fabricated with a fourth adjoining nose portion (not
pictured) extending
from the opposite longitudinal end of the tread overlay 40 from the second
nose portion
44 for covering a stair tread having two open longitudinal ends (i.e., a tread
that does
not abut a stringer at either longitudinal end). During installation, the
tread overlay 40 is
measured, cut, and mounted in a substantially similar manner to the tread
overlay 10
described above. It should be noted that some open-ended staircases feature a
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banister, such as the banister 48, which generally must be removed before the
overlay
40 is installed and can be replaced after installation is complete. Once the
overlay 40 is
installed, the nose portions 44 and 46 are trimmed and installed.
[0039] Referring to FIG. 5, a second alternative embodiment of the present
invention
is contemplated for accommodating the installation of a central runner made
from a
flooring material such as carpeting or tile on a staircase. In this
embodiment, the tread
overlays 50 and riser overlays 52 are similar to the tread overlay 10 and
riser overlay 12
described above, except that each of the tread overlays 50 and riser overlays
52 has a
width that is less than half the width of the stair treads 54 and risers 56 of
the underlying
stair case 58. The tread overlays 50 and riser overlays 52 are mounted over
the
opposing longitudinal ends of their respective stairs in abutment with the
stringers 60
and 62 (only the stringer 60 is shown in FIG. 5). Each pair of tread overlays
50 and
each pair of riser overlays 52 thus define an exposed central channel 64 in
which
flooring material, such as carpeting or tile, can be installed in a
conventional manner in
direct contact with the existing staircase 58 to provide the staircase 58 with
a central
runner. The flooring material of the runner thereby sits flush with the
longitudinally-
adjacent tread overlays 50 and riser overlays 52 and presents an attractive,
uniform
appearance.
[0040] An exemplary embodiment of one of the manufacturing processes of the
present invention is illustrated in Figures 6, 7, and 8. For purposes of this
detailed
description, the manufacturing process of the stair tread, FIG. 6, shall be
described first
and the manufacturing process of the nose, FIG. 7, shall be described second.
It should
be noted, however, that this does not dictate the order in which the tread and
nose must
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be manufactured. The manufacturing process of the tread and nose may occur
simultaneously or at different times. Subsequently, the manufacturing process
in which
the tread and the nose are combined are illustrated in FIG. 8.
[0041] An exemplary manufacturing process for the stair tread, as
illustrated in
Figure 6, commences in step 101 with the incoming of raw material. The raw
material
may be dried in step 102. For example, the raw material may be kiln dried to
approximately 6-7% moisture. The raw materials in step 103 are then cut into
boards of
correct rough thickness. In an exemplary embodiment, the boards are cut into a
rough
thickness of about 5/4 inches. In step 104, the thick rough boards are cut
into two
pieces of desired thickness. In this exemplary embodiment, the thickness of
each piece
should be greater than 3/8 inches. In step 105, the boards are cut to an
approximate
finish length.
[0042] In step 106, the sides or edges of the boards are machined to
prepare the
edges for gluing. A joiner may be used to prepare the edges of the boards for
joining the
sides of the boards together. The boards, in step 107, are then color and
grain matched
to prepare for tread body gluing. In order to manufacture a tread equal to the
width of a
step in a staircase, multiple boards are placed together in step 108 such that
the total
width of the planks make up the width of the tread body (i.e. the width of a
step).
Preferably, the width would be about 11 inches across but it can be any other
size to fit
a customized step. The boards placed together are joined at the edges by
gluing or
using a joiner. Depending on the width of the steps, the manufacturing process
may be
modified to accommodate for different widths. For example, boards could be
added,
removed, or cut to create any desired width. In step 109, the multiple boards
are
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adhered together using glue and pressure to create the tread body. Pressure
may be
applied manually or through an automated means such as an automated press
machine. In addition, biscuits, a tongue and groove design, or any combination
thereof
may also be used in the process of gluing the multiple boards or blanks
together. It
should be noted that steps 102 through 109 could be performed in various
orders to
achieve the desired outcome of a cut and ready tread body. Further, several
steps
within steps 102-109 may be combined into one step.
[0043] The manufacturing of the overlay nose in this embodiment, as
illustrated in
Figure 7, runs concurrently and/or separately with the manufacturing of the
overlay
tread illustrated in Figure 6. The manufacturing process of the stair nose
commences in
step 121 with the incoming of raw material. In step 122, the raw material may
be dried.
For example, the raw material may be kiln dried to approximately 6-7%
moisture. In
step 123, one or more pieces of raw material are cut or glued together
creating 2 inch x
2 inch blocks or strips. In step 124, the 2x2 blocks or strips are cut to the
approximate
finish length. In step 125, the 2x2 blocks are then color and grain matched
with the
tread body from step 107.
[0044] The 2x2 blocks may be formed of multiple pieces. For example, the
process
may use 2x1 rough strips which are grain matched with a second 2x1 strip. The
two
strips are adhered together using glue and pressure such that the two 2x1
blocks
together make up a 2x2 nose block. In addition, biscuits, a tongue and groove
design,
or any combination thereof may also be used in the process for connecting the
multiple
strips together to form the nose block.
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[0045] In step 131, using glue and pressure, the 2x2 nose block is adhered
to the
bottom, top, or edge of the tread body to create the tread blank. In the
exemplary
embodiment, the nose block is adhered on the bottom of the tread body with the
long
edge of the tread and the nose block flush. In an alternative embodiment, the
nose
block can be positioned next to the board such that the length of the nose and
board
combination is equal to the length of the board plus the block. The nose block
is
adhered using glue and pressure. The nose block may also be adhered using glue
and
pressure in combination with biscuits or a tongue and groove design.
[0046] In step 132, the tread blank is placed on a router table or computer
numerical
control ("CNC") fixture or machine. Typically, a CNC machine consists of a
table that
moves in the X and Y axes with a tool, spindle, or cutter that moves in the Z
direction.
However, in the exemplary process, the cutter is moving in multiple axes
including the
X, Y, and Z axes. The position of the tool is driven by motors through a
series of step-
down gears which provide highly accurate movements. The CNCs often have
multiple,
fast changing cutter heads which allow the CNC machine to change cutting tools
automatically by the rotation of the cutting head. The cutting heads used
might include
various metal cutting heads, drill bits, router bits, laser cutting, flame and
plasma
cutting, or any other cutting head. The item being milled is placed on a
fixture. In our
exemplary embodiment, the tread body is placed on a fixture with holes in the
fixture.
The holes on the mounting fixture work in combination with a suction element
which
sucks the tread to the fixture to secure the tread in place while the tread is
milled by the
CNC machine. The CNC machine also uses various guides and blocks to help align
the
tread during milling.
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[0047] The CNC machine or router, in step 133, then cuts or mills out a
shape on the
inside of the nose block. In a preferred embodiment, the shape on the inside
of the nose
is a concave shape which fits over the rounded bullnose of many stair treads.
The
cutting of milling could be accomplished in one ore more passes. The CNC
machine
may use one or more cutter heads to cut out the inner shape of the nose. In
cutting out
and shaping the inner shape of the nose for the concave shape, the CNC machine
needs to cut out approximately 1 and 11/16 inches of the 2 inch nose block,
leaving an
approximate 5/16 inch thick front nose edge. It should be noted that thickness
of the
frontal edge (i.e. 5/16 inch) may vary depending on the staircase, and thus,
the process
may be designed to cut out more or less than 1 and 11/16 inches of the 2 inch
nose
block.
[0048] In this exemplary embodiment, the process of forming the inside nose
profile
has the CNC machine make two passes. In the first pass, the CNC machine cuts
half of
the inside of the nose in the step 133. Then the CNC machine makes a second
pass
and cuts the remaining shape on the interior surface of the nose. The
manufacturing
process is not limited to two passes, but may consist of multiple passes to
cut out the
shape of the inner surface of the nose. Once the concave inner portion of the
nose is
cut out, the tread body may be flipped or rotated with the nose portion placed
on a nose
fixture.
[0049] In step 134, the CNC machine cuts the outer portion or surface of
the nose
block to form the outside shape of the nose. In the exemplary embodiment, the
outside
shape or profile of the nose is convex.
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[0050] Alternatively, the outer portion of the nose (step 134) could be cut
before the
inner portion of the nose (step 135).
[0051] An optional step or process (step 135) has the CNC machine mill the
top and
or bottom of the tread to a desired thickness such as 3/8" inches. In step
136, a
conveyer belt sander shaped to match the profile of the outer nose surface is
used. The
tread board and nose combination is sanded using the conveyer belt sander to
shape
and smooth the outside of the nose such that it has a smooth rounded shape.
Step 136
could also be done manually. In step 137, the tread body is sanded or planed
to
provide a smooth top surface. The sanding steps in 136 and 137 could include
multiple
steps from rough sanding to finish sanding with multiple machines at different
sanding
grits. In an optional step 138, the overlay may be completed with stain and/or
a
finishing coating, such as polyurethane.
[0052] After finishing the tread board, the process ends in step 139. The
product of
the process provides a solid, one piece, wooden, stair tread overlay with a
concave
inner surface nose portion.
[0053] In an alternative embodiment of the present manufacturing process,
the
blanks, boards, and nose blocks may be cut to different widths, thickness,
lengths, and
heights such that the overlay may be customized to fit over different
staircases. For
example, the number of blanks glued together in steps 108 through 109 may vary
depending on the width of the steps (i.e. the width of the board may be
greater or less
than 11 inches). As a second example, the blanks in step 105 may be cut to
different
lengths depending on the length of the steps (i.e. the blanks may be cut to a
length of 4
feet instead of a standard 3 foot length).
CA 02809074 2013-03-13
[0054] It should be noted that the present manufacturing process is not
limited to a
CNC machine, and that the milling and cutting of the board and nose block may
be
done manually or by a similar automated machine. Further, the present
manufacturing
process is not limited to the step order described in Figures 6, 7 and 8; some
steps may
be omitted, combined, or switched without losing the durability, integrity,
and
attractiveness of the end product, a solid wood staircase overlay with a
concave inner
nose surface. For example, the CNC machine may be used to cut out a concave
shape
of the inner nose before attaching the nose to the board.
[0055] Further, the manufacturing process is not limited to milling or to
solid wood.
The process can be altered to make use of particle boards and laminates. In
this
embodiment, wood fibers or wood particles are combined with a glue or epoxy to
adhere the particles together and then pressed and formed into a wood fiber
tread
blank. The tread blank may be formed and pressed into the desired shape
including the
J-shape profile or nose with a concave inner surface. A laminate wood grain
layer is
adhered to the wood fiber tread blank which may be adhered before or after it
is
pressed into the J-shape profile. By way of example, the wood fibers and epoxy
mix
may be poured into a mold with a J-shape or concave inner nose surface profile
and
pressure formed, extruded through a J-shaped press, or formed into a flat
fiber board
shape and then having an end or edge of the board bent around a J-shaped mold
while
the fiber board is permeable. In all instances the wood grain top laminate
layer may be
added prior to the fiber board being shaped or after the fiber board is
shaped.
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CA 02809074 2015-08-18
[0056] Alternatively, the wood fiber tread blank may be formed with a block
nose
section and a tread section. In this scenario, the fiber block nose section
can be milled
as in Figure 7 to form the J-shape profile or concave inner surface nose.
[0057] This detailed description in connection with the drawings is
intended
principally as a description of the presently preferred embodiments of the
invention, and
is not intended to represent the only form in which the present invention may
be
constructed or utilized. The description sets forth the designs, functions,
means, and
methods of implementing the invention in connection with the illustrated
embodiments. It
is to be understood, however, that the same or equivalent functions and
features may
be accomplished by different embodiments that are also intended to be
encompassed
within the scope of the invention and that various modifications may be
adopted without
departing from the invention or scope of the following claims.
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