Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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S STAIRTREAD MADE OF A COMBINATION OF HIGH QUALITY WOOD AND
LOW QUALITY MATERIAL
BACKGROUND OF THE INVENTION
1. Field of the invention:
The present invention relates to a stairtread comprising a core layer
consisting of
low quality material, in particular but not exclusively low quality wood, and
a top
layer and nose member made of solid high quality wood.
2. Brief description of the prior art:
Conventional wooden stairtreads are made of elongate wooden lamellas each
made of a single solid piece of high quality wood, these elongate wooden
lamellas
being assembled, i.e. glued laterally adjacent to each other to form the
tread.
This structure has the drawback of requiring a large quantity of high quality
wood.
In the present disclosure and in the appended claims, the expression "high
quality
wood" is intended to designate wood of sufficient quality to be used in making
the
elongate wooden lamellas of conventional wooden treads, while the expression
"low quality wood" relates to wood of insufficient quality and usually
discarded
upon manufacture of conventional wooden treads. Regarding the expression "low
quality material" it includes low quality wood and secondary materials such as
medium or high density fibre materials.
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OBJECTS OF THE INVENTION
An object of the present invention is therefore to provide a stairtread having
the
aesthetic appearance of a solid wood stairtread and presenting a structural
stability comparable to that of conventional wood treads, but having a core
layer
composed of low quality material, in particular but not exclusively low
quality wood
usually disposed of. Accordingly, low quality wood normally discarded finds
application in the stairtread of the invention to help to preserve our natural
resources and to reduce consumption of high quality wood material becoming
every day more rare and difficult to obtain.
SUMMARY OF THE INVENTION
More specifically, in accordance with the present invention, there is provided
a
stairtread comprising an elongate nose member consisting of high quality wood
and having a first longitudinal edge surface and a second longitudinal edge
surface which is rounded in cross section to form a tread's nose, and an
elongate
tread body comprising a core layer having a top face and a top layer having a
bottom face applied and glued to the top face of the core layer. The core
layer is
made of a plurality of elongate thick lamellas made of low quality material
and
glued laterally adjacent to each other, the top layer is made of a plurality
of
elongate thin lamellas made of high quality wood and glued laterally adjacent
to
each other, the tread body comprises a longitudinal edge surface applied and
glued to the first longitudinal edge surface of the nose member, and the top
layer
and nose member define high quality wooden and apparent top and nose
surfaces of the stairtread.
Preferably, the first elongate thick lamellas of the core layer are made of
low
quality wood, at least one of the elongate thick lamellas of the core layer
comprises a plurality of sections of low quality wood assembled end to end,
the
elongate nose member and each elongate thin lamella of the top layer is made
of a single solid piece of high quality wood.
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According to other preferred embodiments, the stairtread further comprises a
bottom layer made of high quality wood and having a top face applied and glued
to the bottom face of the elongate tread body, and the bottom layer comprises
a
plurality of laterally adjacent thin elongate lamellas each cut in a single
solid piece
of high quality wood.
Also in accordance with the present invention, there is provided a method of
fabricating a stairtread, comprising the steps of:
- making an elongate nose member made of high quality wood and
having a first longitudinal edge surface and a second longitudinal
edge surface which is rounded in cross section to form a tread's
nose;
- making elongate thicker core lamellas of low quality material;
- making elongate top lamellas of high quality wood having respective
bottom faces;
- gluing the elongate thicker core lamellas laterally adjacent to each
other to form an elongate core layer of low quality material having
a top face;
- assembling the elongate thin lamellas to form an elongate top layer
of high quality wood, the assembling step comprising gluing the
elongate thin top lamellas laterally adjacent to each other and gluing
the bottom faces of the top lamellas to the top face of the core layer;
and
- applying and gluing the first longitudinal edge surf ace of the nose
member to a longitudinal edge surface of the core body.
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Therefore, the top layer and nose member define high quality wooden apparent
top and nose surfaces of the stairtread.
The present invention further relates to a stairtread comprising a plurality
of
elongate members assembled laterally adjacent to each other, each of the
elongate members comprising a core lamella made of low quality material and
having a top face. Each elongate member also comprises a top lamella made of
high quality wood and having a bottom face applied and glued to the top face
of
the core lamella. Also, each pair of laterally adjacent elongate members have
respective edge surfaces applied and glued to each other, the top lamellas of
the
laterally adjacent elongate members define a high quality wooden apparent top
surface of the stairtread, and the core lamellas of the laterally adjacent
elongate
members define a low quality, non apparent bottom surface of the stairtread.
According to another aspect of the subject invention, there is provided a
method
of fabricating a stairtread, comprising the steps of:
- making elongate core lamellas of low quality material having
respective top faces;
- making elongate top lamellas of high quality wood having respective
bottom faces;
- applying and gluing the bottom faces of the top lamellas to the top
faces of the core lamellas, respectively, to form elongate members;
and
- assembling the elongate members laterally adjacent to each other,
the assembling step comprising applying and gluing to each other
respective edge surfaces of each pair of laterally adjacent elongate
members.
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5 wherein (a) the top lamellas of the laterally adjacent elongate members
define a
high quality wooden apparent top surface of the stairtread, and (b) the core
lamellas of the laterally adjacent elongate members define a low quality non
apparent bottom surface of the stairtread.
By using core layers made of low quality wood, the stairtread structure in
accordance with the present invention reduces the quantity of high quality
wood
required to construct the stairtread, but does not affect the aesthetic
appearance
of that stairtread.
The objects, advantages and other features of the present invention will
become
more apparent upon reading of the following non restrictive description of
preferred embodiments thereof, given by way of example only with reference to
the accompanying drawings.
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BRIEF DESCRIPTION OF THE DRAWINGS
In the appended drawings:
- Figure 1 is an exploded, perspective view of a preferred
embodiment of a wooden stairtread in accordance with the present
invention;
- Figure 2 is a top, rear perspective view of the wooden stairtread of
Figure 1;
- Figure 3 is a bottom, rear perspective view of the wooden stairtread
of Figures 1 and 2;
- Figure 4a is a longitudinal, cross sectional view showing a butt joint
for assembling end to end sections of low quality wood and thereby
form an elongate wooden lamella usable in the construction of the
stairtread of Figures 1-3;
- Figure 4b is a longitudinal, cross sectional view showing a finger
joint for assembling end to end sections of low quality wood and
thereby form an elongate wooden lamella usable in the
construction of the stairtread of Figures 1-3;
- Figure 4c is a longitudinal, cross sectional view showing a halved
joint for assembling end to end sections of low quality wood and
thereby form an elongate wooden lamella usable in the construction
of the stairtread of Figures 1-3;
- Figure 4d is a longitudinal, cross sectional view showing a tongue
and groove joint for assembling end to end sections of low quality
wood and thereby form an elongate wooden lamella usable in the
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construction of the stairtread of Figures 1-3;
- Figure 4e is a longitudinal, cross sectional view showing a dovetail
halved joint for assembling end to end sections of low quality wood
and thereby form an elongate wooden lamella usable in the
construction of the stairtread of Figures 1-3;
- Figure 5 is an elevational end view of a second preferred
embodiment of the wooden stairtread in accordance with the
present invention; and
- Figure 6 is an elevational end view of a third preferred embodiment
of the wooden stairtread in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred embodiment of the wooden stairtread in accordance with the
present invention illustrated in Figures 1-3 is generally identified by the
reference
1.
In the embodiment of Figures 1-3, the wooden stairtread 1 comprises four
elongate wooden members (lamellas) 2, 3, 4 and 5, and an elongate longitudinal
nose member 6, each having a length corresponding to the length of the
stairtread
1.
The nose member 6 is cut into a single solid piece of high quality wood and
comprises a longitudinal edge surface 7 which is rounded in cross section to
form
the nose of the stairtread. The nose member 6 comprises another generally flat
longitudinal edge surface 8.
The wooden members 2, 3, 4 and 5 are rectangular in cross section to be
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g
assembled laterally adjacent to each other as will be described hereinafter.
More specifically, wooden member 2 is formed of a core lamella 9 made of low
quality wood, and of a top lamella 10 made of high quality wood and having a
bottom face applied and glued to the top face of the core lamella 9. In the
example of Figures 1, 2 and 3, the core lamella 9 is made of three wood
sections
11, 12 and 13 assembled (glued or not) end to end. Regarding the top lamella
10,
it is cut into a single solid piece of high quality wood. As shown, the core
lamella
9 made of low quality wood is well thicker than the top lamella made of high
quality wood.
Wooden member 3 is formed of a core lamella 14 made of low quality wood, and
of a top lamella 15 made of high quality wood and having a bottom face applied
and glued to the top face of the core lamella 14. In the example of Figures 1,
2
and 3, the core lamella 14 is made of three wood sections 16, 17 and 18
assembled (glued or not) end to end. Regarding the top lamella 15, it is cut
into
a single solid piece of high quality wood. Again, the core lamella 14 made of
low
quality wood is well thicker than the top lamella 15 made of high quality
wood.
Wooden member 4 is formed of a core lamella 19 made of low quality wood, and
of a top lamella 20 made of high quality wood and having a bottom face applied
and glued to the top face of the core lamella 19. In the example of Figures 1,
2
and 3, the core lamella 19 is made of two wood sections 19' and 19" assembled
(glued or not) end to end. Regarding the top lamella 20, it is cut into a
single solid
piece of high quality wood. As shown, the core lamella 19 is well thicker than
the
top lamella 20.
Outer wooden member 5 is formed of a core lamella 21 made of low quality wood,
and of a top lamella 22 made of high quality wood and having a bottom face
applied and glued to the top face of the core lamella 21. In the example of
Figures
1, 2 and 3, the core lamella 21 is cut into single solid piece of low quality
wood.
Tests have demonstrated that providing the outer wooden member 5 with a solid
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core lamella 21 strengthens the stairtread 1. Regarding the top lamella 22, it
is cut
into a single solid piece of high quality wood. As shown, the core 15 lamella
21 is
well thicker than the top lamella 22.
Wooden member 2 comprises a first generally flat longitudinal edge surface 23
applied and glued to the generally flat edge surface 8 of the nose member 6,
wooden member 3 comprises a first generally flat longitudinal edge surface 24
applied and glued to a second generally flat edge surface 25 of wooden member
2, wooden member 4 comprises a first generally flat longitudinal edge surface
26
applied and glued to a second generally flat edge surface 27 of wooden member
3, and wooden member 5 comprises a generally flat longitudinal edge surface 28
applied and glued to a second generally flat edge surface 29 of wooden member
4.
The wooden members 2, 3, 4 and 5 and the nose member 6 are therefore
assembled laterally adjacent to each other to form the stairtread 1 of Figures
1-3.
As shown in Figure 2, the outer top surfaces 30, 31, 32 and 33 of the top
lamellas
10, 15, 20 and 22 of the wooden members 2, 3, 4 and 5, and the outer top
surface
34 of the nose member 6 define a 5 high quality wooden apparent top surface of
the stairtread 1. As illustrated in Figure 3, the outer bottom surfaces 35,
36, 37
and 38 of the core lamellas 9, 14, 19 and 21 of the wooden members 2, 3, 4 and
5 define a low quality wooden, non apparent bottom surface of the stairtread
1.The outer bottom surface 39 of the nose member 6 defines a high quality
wooden apparent front bottom surface of the stairtread 1.
Finally, as mentioned in the foregoing description, the rounded longitudinal
edge
surface 7 is of member 6 forms a high quality wooden apparent nose surface of
the stairtread 1.
As the core lamellas 9, 14, 19 and 21 are made of low quality wood normally
disposed of, and since the top lamellas 10, 15, 20 and 22 are thin, the
quantity of
high quality wood required to fabricate the stairtread 1 in accordance with
the
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5 present invention is greatly reduced. For these two reasons, the stairtread
in
accordance with the present invention saves wood, but without affecting the
aesthetic appearance of the stairtread or the stability of the staircase.
Figures 4a-4e are longitudinal, cross sectional views showing different
joints,
10 glued or not, and usable to assemble end to end the wood sections forming
the
core lamellas 9, 14 and 19. For example, butt joints (Figure 4a), triangular
double
notch joints (Figure 4b), halved joints (Figure 4B), tongue and groove joints
(Figure 4d) and dovetail halved joints (Figure 4e) can be used.
Figure 5 shows the bottom surfaces of the core lamellas 9, 14, 19 and 21
covered with respective additional lamellas 40, 41, 42 and 43 of high quality
wood.
The advantage of the structure of Figure 5 is that the top and bottom surfaces
of
the tread are both made of high quality wood.
In the embodiment of Figure 6, the stairtread 1 comprises an elongate tread
body
comprising a core layer made of lamellas 44-47, of low quality wood and of
which
the width may vary. To the top surface of the core layer are applied and glued
top
lamellas 48-52 of high quality wood to form a top layer. The core lamellas 44-
47
are glued laterally adjacent to each other. In the same manner, the top
lamellas
48-52 are glued laterally adjacent to each other. The width of the top
lamellas 48-
52 may vary with respect to each other and with respect to the width of the
core
lamellas 44-47. The number of top 48-52 and core 44-47 lamellas may also vary.
Finally, the elongate tread body comprises a longitudinal edge surface 53
applied
and glued to a flat edge surface 54 of an elongate, longitudinal nose member
55
cut into a single solid piece of high quality wood.
Preferably, the high quality wood and low quality wood used to fabricate a
stairtread according to the invention will be of the same species. However, it
is
within the scope of the present invention to use high and low quality wood
materials of different species.
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It is also within the scope of the present invention to use low quality
materials
other than low quality wood to fabricate the core lamellas 9, 14, 19, 21 and
44-47.
For example, medium or high density fibre material can be envisaged.
Tests have demonstrated that a stairtread according to Figures 1-3 is 65% to
70%
as solid as a conventional wooden stairtread made of elongate solid wood
lamellas glued laterally adjacent to each other. More specifically, a
stairtread as
illustrated in Figures 1-3 is capable of supporting at least 2000 pounds,
which is
well sufficient to meet with the standards of the industry.
As the core of the stairtread according to Figures 1-3 is made of solid wood,
the
balusters or spindles installed on the stairtread are as sturdy as in the case
of a
conventional wood tread.
Finally it should be mentioned that, in the stairtread as illustrated in
Figures 1-3,
the quantity of high quality wood required is reduced by 60%.
Although the present invention has been described hereinabove by way of a
preferred embodiment thereof, this embodiment can be modified at will, within
the
scope of the appended claims, without departing from the spirit and nature of
the
subject invention.
