Note: Descriptions are shown in the official language in which they were submitted.
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TIE-DOWN SYSTEM FOR FABRIC COVERED BUILDINGS
This invention deals with the field of fabric covered buildings and in
particular with a
system of securing the fabric covering of such buildings to the framework or
ground
anchoring foundation of the buildings.
BACKGROUND
Fabric covered buildings are well known wherein a framework is secured to a
ground
anchoring foundation and then covered with fabric. Such buildings are
economical, fast
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and easy to erect and maintain, durable and easy to relocate. These features
have made
fabric covered buildings very popular, and led to demand for ever longer and
wider
buildings. However, these wider buildings are subject to much higher loads
from wind,
snow and so forth.
The fabric covering of such buildings is generally secured in two ways. It may
be in
sections, each of which covers the area between two arches of the framework
and is
slidingly secured along the perimeter of each arch to allow for pulling the
section tight or
tensioning, or the fabric may be a single large piece which is pulled over the
framework
and attached at each edge to the framework or the foundation.
The present means for securing the fabric to the framework and the foundation
is most
often by a rope through holes in, or rings attached to, the edge of the fabric
covering.
The rope most often weaves from holes in the fabric to the framework and back
to the
fabric and so forth along a side of the building. To tighten the fabric, the
rope must be
pulled tight and knotted. This method, when used in larger buildings, notably
those with
a one-piece fabric covering, often fails as the holes in the fabric tear
because of the
increased stress exerted by wind, snow and so forth. In extremely large
buildings, with
widths over 120 feet, it is preferred to use a cover that is in sections
between the arches,
and secured to the arches on each side. The arches may be quite far apart, 15
feet or
more, and again the prior art rope tie-down system is subject to failure.
The tension on the fabric covering must be adjusted periodically to compensate
for
stretching. The rope must be untied, pulled tighter and re-knotted. This is
time-consuming and imprecise, and it is difficult to maintain the required
tension while
knotting the rope. On the larger buildings contemplated herein, this problem
can be
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particularly acute. Proper tension is necessary to avoid excess movement of
the fabric
cover due to wind and snow loads, and so forth.
The sides of the fabric where the rope passes is difficult to seal against the
weather. The
rope is often tied to a board attached to the framework or foundation. This
leaves a gap
between the fabric and the ground, which gap is often sealed by a wooden
construction
along the inside of the building, leaving the rope on the outside of the
building, exposed
to the elements. Often fabric covered buildings are mounted on a stub-wall, in
which
case the needed sealing construction is already present. In situations where
the building
is mounted on pilings alone, an improved sealing system would be advantageous.
It
would also be a benefit to cover the rope or other securing mechanism from the
elements.
Truss arches may be utilized to provide the increased strength needed for a
larger fabric
covered building, however an improved tie-down system would be desirable in
order to
take advantage of the truss arch strength by increasing the loads to which the
fabric cover
may safely be subjected.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a system for securing the
fabric
covering of fabric covered buildings that is stronger than present systems and
which
allows for fast and accurate adjustments of the tension on the fabric
covering.
It is a further object of the present invention to provide such a system that
provides for
easier and closer sealing of the fabric to the foundation.
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It is a further object of the present invention to provide such a system that
may be used
where the fabric covering is in sections, each of which covers the area
between two
arches of the framework and is secured along the perimeter of each arch, and
where the
fabric may be a single large piece which is pulled over the framework and
attached at
each edge to the framework or the foundation.
The invention accomplishes these objects providing in one aspect a system for
securing
the fabric cover of a fabric covered building comprising: a framework for
supporting the
fabric cover, the framework having two opposite sides and two opposite ends,
each side
being adapted for attachment to a ground-anchoring foundation; a fabric cover
over said
framework, said fabric cover having two sides, each side being in proximity to
the bottom
of each side of said framework , and two ends, each end being in proximity to
each said
end of the framework; at least one tie-down member fastened along each side of
said
fabric cover; and a plurality of individually adjustable tensioning means
positioned along
each side of said fabric cover, attached at one end thereof to one of said tie-
down
members and adapted for attachment at the opposite end thereof to said
framework or a
ground anchoring foundation, said tensioning means exerting an adjustable
force on said
tie-down member in the direction of the ground; wherein said fabric cover is
held in
place by said tensioning means and wherein the tension exerted on said fabric
cover may
be adjusted.
Generally, one tie-down member would extend the full length of the fabric
cover, thereby
providing the most even tension along the whole of the fabric cover. It is
contemplated
however that the tie-down member could be in sections, essentially then being
a plurality
of tie-down members. These sections would be preferably butted up against each
other,
thereby providing substantially even tension, although the free ends of such
sections will
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tend to bend upwards. Placing the tensioning means near the free ends would
reduce this
effect.
In a second aspect the invention provides a system for securing the fabric
cover of a
fabric covered building comprising: a support framework comprising a plurality
of
adjacent arches laterally spaced and secured by purlins between adjacent
arches, the
framework having two opposite sides and two opposite ends, each side being
adapted for
attachment to a ground anchoring foundation; a plurality of fabric cover
sections, each
said section covering the area between two adjacent arches, each said section
having two
sides, each said side being in proximity to the bottom of each side of the
framework , and
two ends, each said end being slidingly secured to one of said adjacent
arches; a
tie-down member fastened along each said side of each fabric cover section;
and a
plurality of individually adjustable tensioning means positioned along each
said side of
each fabric cover section, each said tensioning means attached at one end to
one of said
tie-down members and adapted for attachment at the opposite end thereof to the
framework or the ground anchoring foundation such that the tensioning means
exerts an
adjustable force on said tie-down member in the direction of the ground;
wherein each
said fabric cover section is held in place by said tensioning means and
wherein the
tension exerted on each said fabric cover section may be adjusted.
In this second aspect, each fabric cover section spans the distance between
the arches.
The tie-down member extends only between the arches as well, providing even
tension
on each side of the section.
Thus the invention provides an improved tie-down system for buildings with a
single
fabric cover and buildings with a plurality of fabric cover sections, each
section covering
the area between adjacent arches.
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Fastening of the tie-down member to the fabric cover is most conveniently
accomplished
by inserting the tie-down member into a pocket attached to each side of the
fabric cover.
Cut-outs in the pockets at intervals along their length provide access for
attachment of the
adjustable tensioning means to the tie-down members. Alternatively the tie
down
member could be fastened by passing the member through rings or loops attached
to the
fabric at short intervals so as to maintain an even tension along the side of
the fabric
cover.
The pockets may be formed and then fastened to the outer edge of the fabric,
or formed
by folding the outer edge of the fabric cover and fastening the outer edge to
the fabric
cover along a line parallel to and removed from the outer edge.
The pockets may be formed and fastened by sewing, however the holes in the
fabric that
result from sewing weaken the fabric. While this is not normally a problem,
the
increased forces exerted on larger buildings may be such as to cause the sewn
pockets to
tear along the sewn seams. Heat sealing of the fabric to form the pocket
provides a
stronger seam with no holes to weaken the fabric at the seam.
The adjustable tensioning means could include a ratchet mechanism to provide
the
needed adjustable force. Most conveniently a winch is mounted on the ground
anchoring
foundation for each arch, typically a piling, and fastened to the tie-down
member.
The tie-down member is most conveniently a tubular member, such as a pipe,
which can
be made in sections for shipping and then put together on site by pipe
connectors or other
conventional means. The tie-down member should have sufficient strength to
resist
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bending when subjected, at the pockets, to the required tensioning forces. As
discussed
above, the sections need not be necessarily joined to provide satisfactory
service.
The sealing of the gap where the fabric cover meets the foundation is
accomplished by
heat sealing a sealing flap along each side of the fabric cover which sealing
flap extends
beyond the side of the cover. The tension exerted on this sealing flap is not
critical since
the cover tension is maintained by the tensioning means acting on the tie-down
member.
The sealing flap may then be attached by nails, screws, ropes and so forth to
any
convenient points on the framework or foundation, or to stakes driven into the
ground.
The sealing flap may also extend over the ground and be covered with back-
fill. A
further advantage of such a sealing flap is that the tensioning means are
covered and
protected from the elements.
To provide the required strength for the wider buildings herein contemplated,
truss arches
are generally utilized, although the disclosed system and its advantages are
appropriate
for use in a building of any width. Each truss arch could be attached to a
piling, being the
ground anchoring foundation.
DESCRIPTION OF DRAWINGS
While the invention is claimed in the concluding portions hereof, preferred
embodiments
are provided in the accompanying detailed description which may be best
understood in
conjunction with the accompanying diagrams where like parts in each of the
several
diagrams are labeled with like numbers, and where:
Figure 1 is a perspective view of the lashing winch;
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Figure 2 is a side view showing the lashing straps attached to the tie-down
member;
Figure 3 is an end view of the lashing winch mounted to a piling and attached
to
the tie-down member, and also showing the attachment of the sealing flap to
boards along the bottom of the framework;
Figure 4 is an end view showing the construction of the pockets and attachment
of
the sealing flap;
Figure 5 is a perspective view of the lashing straps attached to the tie-down
member and the tie-down member located in the pocket;
Figure 6 is a perspective view of the fabric cover laid out prior to
installation on
the framework of the building;
Figure 6A is a perspective view showing the attachment of the lashing straps
to
the lashing winch;
Figure 7 is a perspective view of the completed building;
Figure 8 is a side view from the inside of a building showing a fabric cover
that
extends only between adjacent arches;
Figure 9 is a cross-sectional view along XX in Figure 8 showing the sliding
attachment of the fabric cover section to the arch.
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Figure 10 is a cross-sectional view along YY in Figure 8.
DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS
Figures 1 - 6 show one preferred embodiment of the invention, showing a fabric
covered
building having a single sheet of fabric pulled over the framework and secured
on each
side by adjustable tensioning means attached to the fabric cover and to the
ground
anchoring foundation.
Figure 1 shows one embodiment of the invention wherein the adjustable
tensioning
means is a winch. The lashing winch 1 and detachable handle 2 are shown. The
lashing
winch 1 comprises a ratchet mechanism in this embodiment, however a winch or
come-along using friction clutches or other suitable means is contemplated
within the
scope of the invention.
Figure 2 shows the lashing winch 1 mounted to the pilings 3 by anchor bolts 5
, which
anchor bolts 5 also serve to fasten the truss arch 4 to the pilings 3.
Figure 3 shows the lashing straps 6 attached to the tie-down member 7 at cut-
outs 8 in
pockets 9 and fabric cover 10. The tie-down member 7 passes through loops 11
formed
at one end of the lashing straps 6. The opposite free end 16 of the lashing
straps 6 is
attached to the lashing winch 1.
Figure 4 is an end view of the pockets 9 and tie-down member 7, showing that
the pocket
is formed by folding the outer edge 12 of the fabric cover 10 back and heat
sealing the
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outer edge 12 to the fabric cover 10 at pocket seam 13. Also shown is the
attachment of
the sealing flap 14 to the fabric cover along a flap seam 20 adjacent to the
pocket seam
13. Sewing is an alternative to heat sealing and is illustrated in Figure 2
which shows
stitches 29, however heat sealing is preferred to sewing as no holes are
punctured in the
fabric, which holes weaken the fabric. Alternatively the pockets 9 may be
formed
separately and heat sealed or sewn to the outer edge 12.
Figure 6 shows the fabric cover 10 laid out on the ground adjacent to the
framework 15
of the building, which framework 15 comprises a plurality of truss arches 4.
Truss arches
are utilized to provide the increased strength needed for a wider building
such as that
contemplated by this invention.
Fabric cover 10 has two opposite ends 17 and two opposite sides being the
first attached
side 18 and the second attached side 19. Tie-down member 7 is inserted in the
pocket 9
on the first attached side 18 and through the loops 11 of the lashing straps 6
at the
cut-outs 8. The tie-down member 7 comprises sections of pipe which are
connected
together on-site by conventional means such as pipe couplers. This provides a
single
tie-down member 7 extending from one end of the fabric cover 10 to the other
end
thereof. Alternatively the sections could be left unconnected, and if butted
up against
each other at a point between the pockets 9, could provide some level of
service,
especially if a lashing winch 1 is attached near each free end of each
section.
Sealing flaps 20 are heat sealed along each of the sides 18 and 19, and extend
beyond the
pockets 9. Along the first attached side 18, free ends 16 of lashing straps 6
are attached
to the tie-down member 7 by loops 11 and the opposite free ends 16 are
attached to
lashing winches 1 mounted on each piling 3.
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Figure 7 shows the completed building. The second attached side 19 of the
fabric cover
is pulled over the framework 15. The second tie-down member 7 is inserted into
the
pocket 9 and through the loops 11. The free ends 16 of the lashing straps 6
along the
second attached side 19 are similarly attached to the lashing winches 1
located along the
5 opposite side of the building.
The ends 17 of the fabric cover 10 are pulled into proper position and secured
to the
framework 15 by ropes or other conventional means. The lashing winches 1 are
then
tightened until the proper force is being exerted on the tie-down member 7.
Sealing flaps 14 are secured by screws 21 into boards 22 secured to the
pilings 3. Earth
is often backfilled over the flaps to make a very close seal. The sealing
flaps cover the
lashing winches 1, protecting them from the elements.
The illustrated embodiment includes truss arches for added strength, however
it is
contemplated that the disclosed tie-down system would be advantageous when
used with
any framework.
A second preferred embodiment where the fabric cover comprises fabric cover
sections
30, each of which covers the area between two arches 31 of the framework is
illustrated
in Figures 8, 9 and 10. The fabric cover section 30 is slidingly attached at
each end 32
thereof to an arch 31. The method of sliding attachment is illustrated in
Figure 9, and is
commonly used in the art. The outer edge of the fabric cover section 30 is
wrapped
around a cord 33 and glued or sewn to secure the cord 33. The cord then slides
into the
groove 34 attached to the side of the arch 31. The groove 34 terminates at
groove end 35
somewhat above the bottom of the arch 31 allowing the fabric cover section 30
to flex
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during tensioning. Other sliding attachments known in the art could be used as
well, and
the invention is directed to the novel tie-down system for use with any prior
art.
The pocket 9 is formed in the same manner as in the previous embodiment and
seal flap
14 is also attached in the same manner. The difference is that the fabric
cover section 30
is much shorter, and so are the pocket 9 and the seal flap 14. The pocket 9 is
somewhat
shorter than the length of the fabric cover section 30 so that the tie-down
member 7
extends beyond the ends of the pocket 9 and is exposed for attachment to the
lashing
strap 6. The configuration of Figure 8 is repeated so there is a lashing winch
1 mounted
on each side of each middle arch 31.
Figure 10 illustrates that the sealing flap may simply be covered with earth
36 to retain it
in its proper position.
The foregoing is considered as illustrative only of the principles of the
invention.
Further, since numerous changes and modifications will readily occur to those
skilled in
the art, it is not desired to limit the invention to the exact construction
and operation
shown and described, and accordingly, all such suitable changes or
modifications in
structure or operation which may be resorted to are intended to fall within
the scope of
the claimed invention.
