Note: Descriptions are shown in the official language in which they were submitted.
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TITLE OF THE INVENTION
A wood arch frame system.
FIELD OF THE INVENTION
The present invention pertains to a wood arch frame system, usually curved,
mainly used in
economical agricultural constructions in which the main component are wooden
arch frames
which have a cross-section similar to wood joists presently available in the
building market.
The main component of these frames is the arch segments, which can then be
interconnected to form the arch frames.
BACKGROUND OF THE INVENTION
Wooden joists are increasingly used in a large number of building
applications. They
comprise upper and lower wood chords with a web system composed of a diverse
type of
materials.
One such wood joist may be found in US patent No. 5,867,963 issued February 9,
1999 to
Hershey. Another joist may be found described in Canadian patent application
2,008,043
published July 18, 1991 issued to Lemyre.
The present invention, on the other hand, presents a curved wood structure
that can be
economically used for buildings with diverse free span lengths, and amenable
to a diversity of
covers like fabric, metal cladding or plywood and shingles.
In US patent No. 4,336,678 issued June 29, 1982, wooden joists are described
with a web
member formed of sheet material such as plywood. In the present invention, the
wooden
structure is generalized to linear or curved arch shapes, and specific
solutions are given for
the interconnection between the arch segments that form part of the wood
frame.
In Canadian patent No. 1,059,872 issued August 7,1979 to Philip Sprung, a
building system
is described with steel members covered by fabric. In the case of the present
invention the
improved system that is intended has a curved arch frame structure made of
timber which is
more economical and which makes it easier to implement future building
modifications or
expansions.
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OBJECTS AND STATEMENT OF THE INVENTION
It is an object of the present invention to provide a novel wooden arch frame
system
consisting in manufacturing curved arch segments, which can be interconnected
to form a
wood frame structure. A plurality of these wood frames is spaced over a number
of bays to
create a system that will produce an economical barrel vault type building.
This structure is
then amenable to economical covers like fabric, but can be covered by sheet
metal or
plywood and shingles as well.
The same frames can be used in halves that can be interconnected to assemble a
circular or
round building, which can be an economical solution required in other
agricultural uses.
The present invention relates to a structural wooden arch segment which
comprises: a) an
elongated lower chord; b) an elongated upper curved chord generally but not
necessarily
parallel to the lower chord, and c) a web joining the chords usually of
plywood or OSB
material.
The arch segments connect to produce the wood arch frame in the following
manner: a) the
two chords connect by means of a steel strap bolted to both sides of the
connection, and b)
the web connects to the abutting web by using a wooden bolted web connector of
the same
material as the web.
The chords for each arch segment are made of kiln-dry wood, preferably one
selected from
the group that includes fir-spruce-pine.
Other aspects and further scope of applicability of the present invention will
become apparent
from the detailed description given 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.
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BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is an elevational view of a wooden arch segment made in accordance
with the
present invention.
Figure 2 is a cross-sectional view taken along view line A-A.
Figure 3 is a cross-sectional view taken along view line B-B.
Figure 4 is a cross-sectional view taken along view line C-C.
Figure 5 is a plan view of a building in the shape of a barrel vault composed
of the wood arch
frames built in accordance with this invention.
Figure 6 is a cross section of this building along line D-D showing a typical
wood arch frame
composed of arch segments.
Figure 7 is a plan view of a round building built with the wood arch frames
reported in this
invention.
Figure 8 is a cross-sectional view of the round building built with the arch
frames taken along
view line F-F.
Figure 9 is an enlarged elevational view of the base web panel, which is part
of the web of the
arch segment closest to the support of the wood frame.
Figure 10 is an enlarged elevational view of two arch segments connected with
steel straps
and wooden web connectors.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to Figure 1, representing an arch segment, the main constituent of
the wood arch
frame system, it comprises a curved upper chord 10, an elongated lower chord
11 which can
be linear or curved, both chords being spaced apart and usually parallel.
Between the upper and lower chords is provided a plywood or OSB web panel 12,
adhesively
joined to chords 10 and 11.
At the ends of top chord 10 can be seen the bolts required for the connection
with an abutting
arch segment, and indicated as 16. Similarly, at the ends of bottom chord 11,
the bolts 17
shown are for the connection to another arch segment. The bolts 18 shown in
the stiffeners
15 are required for the connection of the webs of abutting arch segments. We
also observe
web splicers 14 glued at both sides of the web 12, at lines of discontinuity
13.
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In Figure 2, representing cross section A-A taken in Figure 1, the web 12 is
adhesively joined
into grooves shown with the numeral 12a created in the chords 10 and 11, or
alternatively
scarf joints can be used to assure more positive web-chord connection for
handling purposes.
Glue is used to secure this joint.
In Figure 3, representing section B-B taken in Figure 1, we observe the
plywood or OSB web
splicers 14 glued at both sides of the web panel 12, at lines of
discontinuity. The glue used in
securing the splicers as well as that used in the joints between web panels
and chords 10
and 11, preferably has a base of resin resorcinol, such as phenol resorcinol
resin, or one
having a base of urethane or similar products approved for structural wood
products. In
addition, this Figure 3 also indicates alternative possibilities of web
arrangement indicated by
12b, glued to the side of the chords.
Figure 4, shows section C-C taken in Figure 1, at the ends of arch segments,
representing
the wood stiffeners 15, which are glued to web panel 12, and screwed to chords
10 and 11
with screws 16.
Figure 5 represents a typical plan of a building, built with the wood arch
frame system, in
which the frames 20 are spaced apart by a bay length shown as 21, and the
transversal
elements called purlins are shown as 22. The purlin braces 23 are used to
shorten the
unsupported length of the purlins and arch frame chords. The tensor elements
24 are
introduced to give lateral stiffness to the system and also assure that
purlins can be used to
brace the arch chords.
Figure 6 is a representation of cross section D-D taken in Figure 5 above,
representing a
typical wood arch frame, in which in this case there is a central arch segment
30, a support
arch segment 31 and another support arch segment 32. At specific locations
inside the arch
segments the cross section indicates wood stiffeners 33, to which purlins,
shown with the
numeral 22, are connected by screws during the site installation of the full
wood arch frame
system. The special support segments 31 and 32 have a base web panel indicated
as item
35.
Figure 7 represents a round construction built with the arch frame system. The
frames
indicated as 20, are spaced at angles shown with numeral 21A and are connected
at the
center to a hub indicated with the numeral 25. Same as in the barrel vault,
the chords of the
wood arch segments are laterally braced by purlins indicated by numeral 22,
and the system
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attains its spatial rigidity through the use of tensors numbered 24. The
purlin braces 23
contribute to shorten the free buckling length of both purlins 22 and frames
20.
Figure 8 shows a cross section F-F of the round building of Figure 7 showing
mainly the
central hub 25 around which are connected the halves of wood arch frames
constructed as
per the present invention.
Figure 9 represents the base web panel 35, built with the same wood as the
chords, glued
and fastened by lag bolts 42 to the chords 10 and 11. This panel has a hole 43
through which
a steel pin is passed in order to connect it to steel connector 44 which
transmits the external
loads exerted on the wood arch frame to the foundation indicated with the
numeral 45.
Figure 10 is a larger representation of the interconnection between arch
segments, showing
steel straps 51, bolted at both sides of the connection, to chords 10 and 11,
with bolts 52, and
the wood web connector plate 53 connecting the webs of the arch segments at
both sides of
this connection with bolts indicated as 54.
Although the invention has been described above with respect to 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 claims.
