Note: Descriptions are shown in the official language in which they were submitted.
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INFLATABLE BEAM TRUSS AND STRUCTURE
Cross Reference to Related Application
This application claims priority from United States Provisional Patent
Application No. 60/924,847 filed June 1, 2007 entitled Inflatable Beam Truss
and
Structure.
Field of the Invention
This invention relates to the field of inflatable structures and in particular
to an
inflatable beam truss and the resulting inflatable structure using the beam
truss or trusses,
where each beam truss includes multiple separate or segmented pneumatic beams.
Background of the Invention
Inflatable tents for use in camping are known in the prior art and are sold
commercially by for example Airzone Recreation Products of Kelowna, British
Columbia,
Canada. Such tents typically replicate camping tents available commercially
which rely on
bent fibreglass poles for their support structure and instead substitute
inflatable poles which,
when bent, provide the supporting framework for the exterior fabric skin or
canopy of the tent
over which a so-called fly sheet may be mounted. In the other extreme, large
tents are known
in the prior art for use such as by the military for providing field barracks,
field hospitals and
various depot facilities, such tents often being made of canvas and supported
on tubular metal-
pole supporting structures.
Applicant believes that a commercial need exists for relatively large
pneumatically inflatable tent-like structures which are much larger than
conventional
recreational camping tents. It is believed that such structures will find
commercial acceptance
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and use by the owners of large for example sport utility vehicles, boats,
trailers, and other
wheeled vehicles or towables which ordinarily would require a large garage or
shed for their
safe storage and which are often not housed in, for example, conventional
residential homes as
not having extended garage facilities. Also applicant believes that commercial
acceptance and
use of such larger pneumatically inflatable tent-like structures may include
those in the field of
general purpose coverings such as portable corporate sponsorship pavilions for
example for
use in trade-shows, portable pneumatically inflatable recreational and
professional sports
shelters for sheltering equipment, non-engaged players, or sickly or wounded
players on for
example the side-lines of a sports field, portable medical or military or
emergency relief
housing or shelters or the like.
What is required, is a relatively larger pneumatically inflatable structure
which
may be readily transportable in that, when collapsed, the structure is not
exceedingly heavy or
overly bulky so the structure may be transported in light trucks including for
example sport
utility vehicles, in mini-vans, or in the beds of ordinary pickup taucks and
the like, and for
example may be carried by two or more adult males to a convenient location for
their use, and
wherein the structure may be erected using for example a high volume, low
pressure air
compressor running for example from the twelve volt power source of the
vehicle used to
transport the collapsed structure.
In the prior art applicant is aware of the following issued patents
illustrating
aspects of the state of the art in pneumatically erectable structures
including tents:
United States Patent No. 2591829 which issued April. 1952 to Katzenmeyer et
al.; United States Patent No. 2830606 which issued April 1958 to Daugherty;
United States
Patent No. 3145719 which issued August 1964 to Johnson; United States Patent
No. 3899853
which issued August 1975 to Wertman; United States Patent No. 3999333 which
issued
December 1976 to A.marantos; United States Patent No. 4068418 which issued
January 1978
to Masse; United States Patent No. 4197681 which issued April 1980 to
Holcombe; United
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States Patent No. 4271642 which issued June 1981 to Karr; United States Patent
No.
4709718 which issued December 1987 to Nichols; United States Patent No.
4766918 which
issued August 1988 to Odekirk; United States Patent No. 4819389 which issued
April 1989 to
Kihn; United States Patent No. 4825892 which issued May 1989 to Norman; United
States
Patent No. 4876829 which issued October 1989 to Mattick; United States Patent
No.
4901481 which issued February 1990 to Seeley, Jr.; United States Patent No.
4918877 which
issued April 1990 to Dutka; United States Patent No. 5005322 which issued
April 1991 to
Mattick et a1.; United States Patent No. 5007212 which issued April 1991 to
Fritts et al.;
United States Patent No. 5122400 which issued June 1992 to Stewart; United
States Patent
No. 5205086 which issued April 1993 to Heim; United States Patent No. 5247768
which
issued September 1993 to Russo; United States Patent No. 5421128 which issued
June 1995
to Shapless et al.; United States Patent No. 5570544 which issued November
1996 to Hale et
al.; United States Patent No. 5636478 which issued June 1997 to Chen; United
States Patent
No. 5987822 which issued November 1999 to McNiff et al.; United States Patent
No.
6014982 which issued January 2000 to Strevey; and United States Patent No.
6,263,617 which
issued July 2001 to Turcot.
Summary of the Invention
In the field of air inflatable structures, the applicant has determined,
contrary to
conventional wisdom which would require that the pneumatic beams be increased
in diameter
as their length increases in order to support larger enclosures, and in one
aspect of the present
invention, that the use of relatively narrow high aspect ratio pneumatic beams
may be used to
span relatively great distances if a multiplicity of such narrow beams are
combined in side-by-
side parallel array to form a single segmented beam truss.
As used herein the term truss is intended in its alternate meaning from the
conventional, namely, any of various structural frames constructed on
principles other than the
geometric rigidity of a triangle or deriving stability from other factors, as
the rigidity of joints,
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the abutment of masonry, or the stiffness of beams (emphasis added). Thus
a.ccording to one
embodiment of the present invention at least a pair of two relatively narrow
beams are
mounted side-by-side in a length sufficient to span over the desired enclosure
and a third for
example much shorter pneumatic beam is mounted along the pair of beams over
only the
vertex segment of the longer pair of beams. This has been found to provide
remarkable
stiffness to the beam truss.
Although it is understood that the pair of longer beams and shorter vertex
beam
may be used in combination with further longer or shorter inflatable beams all
mounted side-
by-side to one another to span even greater distances, in this aspect of the
present invention,
the pair of longer beams and single shorter vertex beam work in combination
when mounted to
one another to lend sufficient rigidity to the resulting combined pneumatic
segmented beam
truss so as to span relatively greater distances than heretofore possible in
the prior art using
single narrow inflatable beams. This structure also does not necessarily
result in a vertex of
the beam truss which is overly high above the floor of the enclosure. In other
words, it is not
required with the present invention to form, using one or more inflatable beam
trusses, an air-
inflated structure in the manner of a tepee-shape or conventional tent shape
where the vertex is
relatively quite high above the floor of the enclosure, due for example to the
beam truss
forming a semi-circle, in order to provide rigidity to the structure.
In summary, the segmented inflatable beam truss according to one aspect of the
present invention may be characterized as including at least three, that is,
first, second and
third, separate inflatable beams mounted or mountable to one another and
having, respectively,
first, second and third lengths and a substantially constant diameter among
all of the three
beams. Each beam of the three separate beams includes an outer flexible
substantially non-
resilient sleeve along the entire length of the beam and an inner inflatable
bladder extending
substantially entirely along and in the entire length of the sleeve.
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Each beam is substantially linear when unconstrained and inflated. Each beam
is flexible so as to form an arch-shape when opposite ends of the each beam
are constrained by
anchoring of the opposite ends on the ground at a distance between the ends
which is less the
length of each beam.
At least the first and second beams are of substantially equal length and are
mounted adjoined to one another in side-by-side parallel relation so as to be
co-extensive with
on.e another along the arch-shape. The third beam is mounted adjoined to the
first and second
beams so as to extend therealong in side-by-side parallel relation and
positioned so as to
extend over at least a vertex portion of the arch-shape.
Inflatable beam trusses may be employed as a frame for mounting, a canopy
thereto to provide a covered structure such as a housing, tent, shelter,
sports enclosure whether
fully or only partly enclosed, storage facility to name just a few possible
uses of,the many
available. Suell a covered structure may include a plurality of inflatable
beam trusses for
example in a criss-cross pattern as illustrated by way of example herein to
form a dome-style
enclosure, or may for example be employed in a parallel spaced-apart array to
form a quonset-
style enclosure to name just two possible uses of the several or many
available. The covered
enclosures may have doorways, or be otherwise open-ended or open-sided or may
be entirely
open vrith merely a sun-shade on the vertex of the enclosure.
The beam trusses may have various embodiznents. For example, they may
include more than three individual separate inflatable beams. The third beam,
or at least one
or more of the separate beams where there are more than three separate beams
in each beam
truss, may be shorter than the two long separate beams, that is, the minimum
pair of first and
second beams that span the entire length of the truss.
Further, each separate beam may be tubular in shape, for example such as
described in shape and construction in my United States Patent No. 6,263,617,
incorporated
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herein by reference. Advantageously at least the first and second beams are
substantially
dimensionally identical. The third beam may be of substantially the same
diameter as the first
and second beams.
Further still, each of the separate beams, and in particular at least the
first and
second beams have a high aspect ratio, that is, a ratio of length to width
which is much greater
than one. For example, if each separate beam is advantageously uniformly
tubular or
cylindrical in shape when un-bowed, and if each separate beam has a
circumference of
generally twenty-two inches for example, meaning a diameter of approximately
six to seven
inches, and an overall circumferential length arched between where the
opposite ends of the
beam truss are anchored to ground (that is, directly to the ground or to a
base which itself may
be anchored to the ground.) of generally twenty-four feet, then the beam truss
has an aspect
ratio of approximately forty-five (288 inches long: 6.4 inches in diameter).
Brief Description of the Drawings
In drawings which illustrate embodiments of the invention wherein similar
characters of reference denote corresponding parts in each view,
Figure 1 is, in perspective view, one embodiment of the inflatable beam
trusses
according to the present invention employed in a criss-cross fashion to form a
dome-like
enclosure.
Figure l a is, in perspective view, an alterrtative embodiment shown in dotted
outline, the structure of Figure 1.
Figure 2 is, in side elevation view, the structure of Figure 1.
Figure 3 is, in plan view, the structure of Figure 1.
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Figure 4 is, in end elevation view, the structure of Figure 1.
Figure 5 is an enlarged partially cut away view of the underside of the vertex
of
the structure of Figure 1.
Figure 6a is an enlarged partially cut away view taken frox.n. Figure 4.
Figure 6b is an enlarged partially cut away view taken from Figure 4.
Detailed Description of Embodiments of the Invention
In the example illustrated, a relatively large inflatable structure is
supported by
three criss-crossed segmented air beams or inflatable beam trusses 10. It is
understood that the
use of three such beam trusses 10 is by way of example only in that structures
employing
fewer or greater numbers of the beam trusses according to the present
invention may also be
useful.
Thus as may be seen, each beam truss 10 is comprised of a bundle of separate
inflatable tubes or beams. In the illustrated example, each beam truss 10
includes a pair of
long spanning tubes 12a and 12b mounted together side-by-side so as to be
coextensive
between their opposite first and second ends. These longer spanning tubes 12a
and 12b form
an arch extending between their opposite ends when their opposite ends are
fixed to the ground
or to a base such as base sheet 14. Thus with the first and second opposite
ends of the pair of
tubes 12a and 12b constrained by being mounted to for example the outer edges
of base sheet
14, and advantageously, with the edges of the base sheet secured to the
ground, the length of
the spanning tubes dictates that they form an arch because their length is
greater than the
diameter of the base.
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In the illustrated embodiment, which is not intended to be limiting, each
spanning tube 12a and 12b is itself made up of two individual inflatable tubes
mounted end-to-
end at vertex 8 for example by stitching the ends together. In this fashion,
the entire beam
truss 10 may be constructed of a multiplicity of identical shorter, for
example approximately
twenty-four foot long, inflatable tubes which are used to construct, in this
example, the
approximately forty-eight foot long spanning tubes 12a and 12b, and to serve
individually as
the capping tubes 16.
A capping inflatable air tube, such as the illustrated shorter capping tube
16, is
mounted to the pair of spanning tubes 12a and 12b across the vertex 8 of the
arch so as to
extend symmetrically along the arch from the vertex along a distance which is
proportionally
shorter than the length of the spanning tubes. The capping tube 16 provides
both for
strengthening and stiffening of the vertex 8 of the beam truss 10 and for
flattening the
curvature of the upper portion of the beam truss on either side ofthe vertex
along the length of
the capping tube. The flattening of the curvature of the arch reduces the
height of vertex 8
above the base sheet 14 and forces the ends of the spanning tubes where they
extend between
the ends of the capping tube and the base sheet to bulge outwardly and
upwardly thereby
forming more vertical wall portions of the beam truss from the ends of the
pair of spanning
tubes effectively raising the ceiling height around the perimeter of the base
and thereby
making the enclosure more useful towards and around the periphery of the base
sheet.
Thus as may be seen in the illustrated embodiment, which is not intended to be
limiting, the length of the capping tube may be approximately one half of the
length of each of
the spanning tubes so as to provide the strengthening, stiffening and
flattening of the resulting
beam truss 10 when the capping tube is mounted onto the vertex portion of the
pair of
spanning tubes. Thus with each beam truss 10 so formed,,a plurality of beams
trusses may be
mounted in radially spaced array about a vertical axis extending through their
common vertex
so that, with the ends of the plurality of beam trusses mounted to the
corresponding
circumferentially spaced locations around the periphery of the base sheet, a
rigid inflatable
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frame is formed over or under which may be mounted a flexible canopy to serve
as the tent or
other enclosure.
Advantageously, at least one air hose 18 is mounted in fluid communication
between each inflatable tube 12 and 16 in each beam truss 10, and between
adjacent beam
trusses 10 so that the inflation of a first beam trtzss causes simultaneous
inflation of the rest of
the beam trusses in the frame so that the inflatable frame becomes self-
erecting for example
when advantageously the vertices of the beam trusses are mounted to one
another and the ends
of the beam trusses are mounted to the base sheet and also secured to the
ground prior to
inflation. For example, in each beam truss, the pair of spanning tubes 12 and
the capping tube
16 may be mounted to one another by the use of straps which may include hook-
and-loop
fasteners, and similarly, the vertices of each of the beam trusses may be
mounted to one
another also by means of straps or hook-and-loop fasteners or the like. Of
course, the separate
tubes in each beam truss may also be stitched or otherwise fastened to one
another by known.
means in whole or in part, that is, with or without the ffiu-ther use of hook-
and-loop fasten.ing
straps or strips.
As shown in dotted.:,; outline in Figure 1 a, capping tube 16 may in one
embodiment have a length substantially equal to the length of the spanning
tubes 12a and 12b.
In alternative embodiments not illustrated, each beam truss may include more
than two
spanning tubes and more than a single capping tube in order to increase the
strength of the
resulting beam truss to thereby acconunodate spanning greater distances
without the need for
supporting. poles to uphold, for example, the vertex of the inflated
structure.
In one embodiment which is not intended to be limiting, each spanning and the
correspondi.ng capping tube in each beam truss are constructed as a separate
sleeve for each
tube, each sleeve constraining a resilient inflatable inner tuber or bladder
extending the length
of the sleeve. For example, each sleeve may have a circumference of
approximately twenty
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inches and the spanning tubes may be approximately forty-eight feet long and
the capping
tubes may be approximately twenty-four feet long in the illustrated
embodiment.
As will be apparent to those skilled in the art in the light of the foregoing
disclosure, many alterations and modifications are possible in the practice of
this invention
without departing from the spirit or scope thereof. Accordingly, the scope of
the invention is
to be construed in accordance with the substance defined by the following
claims.
