STRUCTURAL WOODEN JOIST

SOLIVE DE CHARPENTE

English Abstract

The structural wooden joist described comprises a lower chord,
an upper chord spaced from the lower chord and an openwork web structure
joining the chords. The web structure includes, between opposite ends
thereof, a series of horizontally spaced trapezoidal laminated panels defining
a series of triangular spacings therebetween; each panel has opposite short
and long sides adhesively joined to the lower and upper chords respectively
and each panel is formed of short obliquely extending boards adhesively
secured edgewise to one another.

French Abstract

Poutrelle en bois comprenant une membrure inférieure, une membrure supérieure espacée de la membrure inférieure et une âme ajourée reliant les membrures. L'âme comprend, entre ses extrémités opposées, une série de panneaux trapézoïdaux espacés horizontalement et délimitant entre eux une série d'espaces triangulaires; chaque panneau a des côtés court et long opposés collés aux membrures inférieure et supérieure respectivement et chaque panneau est formé de courtes planches s'étendant obliquement et collées l'une à l'autre sur les bords.

Claims

The embodiments of the invention in which an exclusive
property or privilege is claimed are defined as follows:

1. A structural wooden joist comprising:
a) an elongated lower chord;
b) an elongated upper chord in a spaced apart
generally parallel opposed relation to said lower
chord;
c) an openwork web structure joining said chords;
said web structure including, between opposite
ends thereof, a series of horizontally spaced
trapezoidal laminated panels defining a series of
triangular spacings therebetween; each said panel
having opposite short and long sides adhesively
joined to said lower and upper chords
respectively; each said panel being formed of
short obliquely extending boards adhesively
secured edgewise to one another.

2. A structural wooden joist as defined in claim 1, wherein
said short and long sides of said panels are secured to said chords by
scarfing.

3. A structural wooden joist as defined in claim 2, wherein
said chords are substantially rectangular in cross-section.

4. A structural wooden joist as defined in claim 3, wherein
each chord is formed of a series of successive boards joined horizontally by
scarfing.




5. A structural wooden joist as defined in claim 1, wherein
each said opposite ends of said web structure defines a laminated panel
having horizontal top and bottom sides, an outer side extending
perpendicularly to said chords and an inner side extending obliquely said
chords; said panels of said opposite ends being formed of short obliquely
extending boards adhesively secured edgewise to one another.

6. A structural wooden joist as defined in claim 5, wherein
said boards are made of kiln dry wood.

7. A structural wooden joist as defined in claim 6, wherein
said wood is selected from the group including fir, spruce and pine.

8. A structural wooden joist as defined in any one of claims
1 to 7 wherein said boards of said laminated panels extend at 30° with
respect to said upper and lower chords.

9. A structural wooden joist as defined in any one on
claims 1 to 7 wherein said boards are adhesively secured to one another by
means of a glue having a base of resin resorcinol.

10. A structural wooden joist as defined in anyone of claims
1 to 7, wherein said lower chord is pre-cambered.

Description

~180'~1~
TITLE OF THE INVENTION
A structural wooden joist.
FIELD OF THE INVENTION
The present invention pertains to a structural wooden joist
used in building constructions.
BACKGROUND OF THE INVENTION
Wooden joist are used increasingly in a number of building
applications. They comprise top and bottom elongate chords with
intervening struts joined to the chords by means of scarfing. One such
1o wooden joist may be found described in Canadian patent application
2,008,043 published July 18, 1991 to Lemyre.
Some web structures have a triangular configuration, such as
the joists described in U. S. patent 4,228,631 issued October 21, 1980 to
Geffe and Norwegian patent 112,944 granted May 6, 1968 to Greimbau-
i5 Lizenz GmBH. However, these structures are produced from a plywood or
other reconstituted grade wooden panels either disposed on either side of
the chords or disposed vertically above another and interconnected by a
structural member. These panels are usually glued and nailed to the chords.




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OBJECTS AND STATEMENT OF THE INVENTION
It is an object of the present invention to provide a novel
wooden joist which consists in having a web structure wherein each panel
is formed of short laminated boards which are adhesively secured to one
another by gluing only thereby enabling an adjustment at the building
location by a simple sawing operation.
The present invention therefore relates to a structural wooden
joist which comprises:
a) an elongated lower chord;
io b) an elongated upper chord in a spaced apart generally
parallel opposed relation to the lower chord;
c) an openwork web structure joining the chords; the web
structure including, between opposite ends thereof, a
series of horizontally spaced trapezoidal laminated
15 panels defining a series of triangular spacings
therebetween; each panel having opposite short and long
sides adhesively joined to the lower and upper chords
respectively; each panel being formed of short obliquely
extending boards adhesively secured edgewise to one
2 o another.
In one form of the invention, the short and long sides of the
panel are secured to the chords by scarfing.
Preferably, the boards are made of kiln dry wood and selected
from the group that includes fir, spruce and pine.
25 Other objects and further scope of applicability of the present
invention will become apparent from the detailed description given




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hereinafter. It should be understood, however, that this detailed description,
while indicating preferred embodiments of the invention, is given by way of
illustration only, since various changes and modifications within the spirit
and scope of the invention will become apparent to those skilled in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is an elevational view of a wooden joist made in
accordance with the present invention;
Figure 2 is a cross-sectional view taken along lines 2-2 of
Figure 1;
~o Figure 3 is an elevational view of one trapezoidal panel used
in the joist of figure 1;
Figure 4 is a side view thereof;
Figure 5 is an elevational view of an end panel of the joist of
figure 1; and
Figure 6 is an enlarged elevational view of two chords sections
connected together.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to figure 1, there is shown a structural wooden joist,
generally denoted 10, which comprises an elongated lower chord 12 and an
2 o upper chord 14 in spaced apart general ly parallel opposed relation to the




lower chord 12. Between the upper and lower chords is provided an open
work web structure consisting of a series of panels horizontally displayed
between two opposite end panels 18 and 20.
Referring more particularly to figure 3, each panel 16 consists
of a series of short obliquely extending boards 20, 22) 24, 26, 28 and 30
which are adhesively secured in an edgewise fashion to one another. The
boards may also be formed of boards which are joined in an endwise manner
by glue or scarfing.
The trapezoidal panel 16 has two opposite inclined edges 16a
io and 16b, a short side 16c and a long side 16d. As can be seen in figure 4,
the short side 16c and long side 16d have a finger sca~ng configuration.
Other connections can be used, such as those illustrated in U.S. patent No.
4,974,389 issued December 4, 1990 to Onysko or U.S. patent No. 5,267,425
issued December 7, 1993 also to Onysko
i5 Referring to figure 5) the two opposite end panels 18 and 20
have an identical configuration which is a four-sided structure that includes,
in the case of panel 18, an oblique side 18a and an opposite side 18b which
is perpendicular to a short side 18c and long upper side 18d. Again) this
panel is formed of a series of obliquely extending boards 32, 34, 36, 38) 40
2 o and 42 which are also adhesively secured to one another in an edgewise
fashion. The opposite sides 18c and 18d also have a finger scarfing
configuration similar to that of sides 16c and 16d of the panels 16.
All the boards used in the laminated panels 16) 18 and 20 are
preferably disposed at an angle of 30°; other angles however may be
used
2 s in accordance with configuration and/or height of the joist.
B




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Referring to figure 6, the elongated chords may consist of a
series of chord sections (two being shown as 12a and 12b) which are again
interconnected by means of finger scarfing and glued to one another in an
endwise manner. Preferably, the chords are pre-cambered.
The wood used for all the boards of the panels is preferably
kiln dry wood) selected from the group consisting of fir, spruce and pine.
Also, the adhesive used in securing the boards together as well as that used
in the finger scarfing sections is a glue preferably having a base of resin
resorcinol, such as phenol-resorcinol resin.
io Although the invention has been described above with respect
with one specific form, it will be evident to a person skilled in the art that
it
may be modified and refined in various ways. It is therefore wished to have
it understood that the present invention should not be limited in scope,
except by the terms of the following claims.

Representative Drawing