Note: Descriptions are shown in the official language in which they were submitted.
Tlle presellt invention relates to a selr-
supporting illflatable ~clual wall structure and more speci-
Eically oE a type utiliæecl ~or forming rooE structures
ancl other Lightweight large span selE-supporting open
structures.
Numerous attempts have been made to provide
a pneumatic clual wall roof or cover made of lightweight
Eabric or synthetic material. One type includes a cel]ular
construction as shown in U. S. Patents 3,247,627, Bird, 1966;
3.030,640, Gosman, 1962; 3,779,847, Turner, 1973; 511,472,
Sumovski, 1893; 2,837,101, Bary, 1958; 3,256,649, Webb, 1966;
3,292,338, MacClarence et al, 1966; 4,186,530, Fraioli, 1980;
3,973,363, Lal'orte et al, 1976 and 3,227,169, Fischer, 1966.
Another form of dual wall inflatable structure
is the type shown in U. S. Patent 4,004,38Q, Kwake. 1977,
in whicll two membranes form the inflatable structure and
tension rods or tension cables extend between anchor points
on the membranes. Examples of this type of structure are
shown in U. S. Patents 3,123,085, Desmarteau, 1964; 2,253,019,
Phane, 1956; 2,743,510, Mauney et al, 1956; 2,698,020, Phane,
1954; 2,657,716, Ford, 1953; 2,636,457, Finlay et al, 1953;
2,016,054, Sentell, 1935; and 3,277~614, Marié, 1966.
The Marié patent, for instance, shows a
framework oE cables Eorming a beam or girder surrounded by
a cover, the cover including prisoner cables attached to
nodes formed from connecting cables res~lting Erom the
triangular structure of the framework. The resulting
structure shown in Figure 7 and 8, is a complex unidirectional
inflated girger or beam.
~377Z~
It is an Elim oE the l~resent invention to provide
an in~cltable struc~ure whicll is lightweight yet selE--
supl)ortillg and lla~ing a struct-lral in~egrity which is
s~l~ficiellt tn provide a cover or roof spanning a large
area. lt i5 contemp1ated that an inflatable structure o~
tlle type described can span a large area without interme-
diate supports if the structure is ~or instance, an arch
having a somewhat parabolic curve and resting only on
its edges. The span can be far greater than that attained
presently by conventional single membrane air supported
buildings using similar type of eanvas material and Far
lighter than any type of construction.
A cons-truction in accordance with the present
invention comprises an inflatable double wall pneuma-tic
structure including a polyhedron eable frame assembly~ The
frame eomprises a pair of spaeed-apar-t grids with eaeh grid
made up of cable tension elements in quadrilateral patterns
with each tension element eonneeted to interseeting tension
elements at nodes in the plane of the respee-tive grid.
Cable tension elements extend be-tween the grids and are con-
nected -to corresponding nodes in the respeetive grids.
The grids de~ine the upper and lower surfaees of the eable
frame, and an air impervious flexible elosed envelope
totally eneloses the eable frame. The walls of the
envelope inelude spaeed-apart anehor means conneeted to
eorresponding nodes on the respeetive grids of the eable
frame such that when the envelope is inElated and subjec-t
to pneumatic pressure, the tension elements forming the
cable frame will be under tension eausing the cable frame
to assume its intended shape.
-- 3
~ construction in accordance with the presellt
invelltioll comprises a pneumatic self-supportin~ structure
lnGluding an inner cable frame and an ou-ter imperv:Lous
envelope. The cable frame,made up of flexible linear
tension elements such as many structurally suitable types
oE cables or woven belts, mainly consists of a pair of
facing and spaced apart grids with each grid being Lormed
by the perpendicular intersection of two series of parallel
and regularly spaced cables interconnected at nodes, and,
flexible linear tension elements or cables extending from
one grid to the other and fixed at their both ends to
each pair oE corresponding facing nodes. The plurality of
the interconnected cable elements are adapted to form a
polyhedron frame, when fully extended, and the envelope
surrounds the frame. The envelope comprises flexible
substantially impervious panels extending about the
perimeter and the outer surfaces of the cable Erame grids
and joined together to ¢ontain the cable ~rame therein. An-
chor means are provided on the inslde face of the envelope
panels to Eirmly tie each nodes of the polyhedron cable
frame to its surrounding envelope whereby when -the
so-Eormed inflatable envelope is inflated, the polyhedron
frame will be Eully erected and each cable element forming
the erected polyhedron cable frame will be ~Inder tension.
~8~2~
In a more sl-eciric embodiment oE tlle preserlt
:invellLioll, tllere is provided .1 uneumatic sel.l~-supl)ortill
roo~ structure aclapted ~o cover a predeterlllillecl aurface,
tlle rooE struc~ure comprisin~ an arcll shaped pneumaticaLly
inELated envelope enclosing a similarly sllaped polyhedron
cable Erame and extending laterally across tlle area to be
covered and longitudinally thereof. The envelope and cable
frame asselllbly is essentially composed of a plurality oE
identical adjaccnt sections connected side by side Witll
each section extending in tlle lateral direction between
parallel support structures which are
longitudinally bordering the area to be covered. Eacil
section includes a top and bottom strip oE impermeable
~aterial, ea~h strip having its parallel longitudinal edges
provided Witll continuous connecting means adapted to
connect adjacent strips at respective seams to form top
and bottom envelope panels respectively. Eacll section
includes also, in between ~he top and bottom strips, a
series of somewhat rectahedron shape cable sub-frames
connected end to end, mutually sllaring the connecting
common faces, each such sub-frames made up oE flexible
cable elements deEining the edges of the rectahedron
thus Eormed and nodes defining tlle junction of tlle cable
edge elemenLs. A tension skirt extends continuously fro
and along the inward side of the seams connecting two
adjacent se~tion strips an~ is fitted with regularly
spaced anchoring means to be an~hored to an arch line
of successive nodes respectively on top and bottom side oE
the cable Erame section. Side strips and end covers complete
tlle envelope and are connected along the edges oE tile strip
assemblies oE tlle top and bottom panels. The tension
skirt nnd l)a~lel s~ction assem~lies ancl the rLexil)le cable
eLements are so dillletlsiotled that wllen tlle envelope allcl cabLe
Erallle 1SSelllb~y i9 completed an-l inElated to maintaill a
interncll pl-essure, all of the cable elements are uncler
tension, thereby pLoviding a self-supporting arch-shapecl
rooE.
When the envelope is inflated and the cable
elements are under tension, the structure becomes quite
rigid, and when the flexible cable el~ments ~orming the
polyhedron cable frame are properly selected and an
adequate number and location oE diagonal cable struts
are provided and fixed to their proper pair of nodes,
the arch-shaped sectionsare like rigid arched trusses.
The span of a roof Eormed by these adjacent arch sections
structurally connected to one another successively may be
quite large ancl certainly the span can cover, without any
intermediate supports, an area greater than any known
single or multiple inflatable membrane structures built
today. The structure of this invention can be utili~ed to
cover stacliums or tennis courts, etc. The preferrecl
curvature oE the arches is parabolic or catenary. The
structure can be adapted to various loads such as in
northern climates where snow weight must be supportecl
during winter months. If a greater load must be carriecl
the air pressure within the envelope can be increased to
meet the requi-red loacls. It is evident t6at by increasing
the air pressure within the envelope, the tension in the
cable elements of the structure will be increased and
so will its rigidity and load bearing capacity.
6 --
77~5
llavin~ thus generally described the nature oE
the inventioll, reEerence wiLl now be made to the
accompilllying drawings, StlOWing by way oE illustratlorl,
a preferred embodiment theroE, and in which:
Figure 1 is a perspective view of an arch-shaped
roof embodying the present invention;
Figure 2 is an end elevation of the roof shown
in Figure l;
Figure 3 is a fragmentary enlarged perspective
view showing details of the present
lnventlon;
Figure 4 is a fragmentary view, partly in
cross-section, showing the side supports;
Figure 5 is a vertical cross-section taken along
line 5-5 of Figure 4;
Figure 6 is an enlarged plan view of ~ detail
of the present invention;
Figure 7 is a vertical cross-section taken
along line 7-7 of Figure 6; and
~ Figure 8 which is on the same sheet of drawings
as Figure 3, is an enlarged perspective
view of another embodiment of a detail
as shown in Fi~ure 3.
Referring now to the drawings and particularly
to Figures 1 and 2 of the drawings, there is shown a large
roof structure 10 including an enve:Lope 11, and including
a number of side-by-side arch sections 12, identified 12a,
12b, 12c,...12n. The complete inflated roof 10 is supported
at each side edge by support members 14. The roof is meant
~.~87~:~5
to cover an area ~. Tlle rooE 10 can be contelllpLated ~IS
being made up oE a ~op impermeable panel of Elexible
material 16 and a bottom panel 18.
The complete rooE envelope 11 can be better
described by reEerring to the individual identical sections
12a, 12b, 12c,...12n. The sections are joined together to
form the complete impermeable air-tight envelope with an
internal cahle ramework 20 which is made up of side-by-side
rectahedron shape sub-frames connected in end-to-end series
in each section 12a, 12b, 12c,... 12n.
Typical sections 12b and 12c are illustrated in
Figure 3. Each section 12b and 12c includes an upper
strip 22 and a lower strip 24. Adjacent strips 22, Eor
instance, are connected along their respective edges by
means oE threads, in the present embodiment, to form a
seam 26. Similarly, the strips 24 are connected along
their edges to form seams 28. Each strip is made oE a
suitable material such as vinyl reinforced with nylon3
Kevlar or Dacron or other ~uitably strong woven material.
~ach strip 22 and 24 extends Erom one side oE the envelope 11
to the other, that is, the complete length of a section 12b
and 12c, or from one support member 14 to the other.
Selected str.ips 22 and 24 could be cu-t
longitudinally into two parts and provided with an inter-
locking Eastener system as shown in Figur.es 6 and 7, which
would divide the panels into modules of several sections
In this case, the cut edges of the strips 22 and 24 may be
folded over and sewn and spaced-apart cuts making loops 23
may be provided in which dowels 21 are fixed and adapted
to interlock as shown in Figures 6 and 7. Each dowel may
-- 8
~t7~2~
have a rounclecl end 25 and a complementary female ~locket
portiol~ 27 aclapted to receive ttle rounded end 25 oE nn
adjacellt dowel 21. The tension on tha strip material rorces
the interlo~king the clowels an~l provides for an air-tight
seam.
Referring back to Figure 3, each of the seams 26
and 28 is further provicled with an anchoring skirt 30 and 32
respectively. These anclloring skirts are of strong woven
material and include a belting or overlapped webbing
33 to reinforce the edges thereof. In the present embodiment,
the anchoring skirts 30 and 32 are scalloped to form gradual
arch-sllaped segments segments as illustrated with an annular
reinforcing eyelet ring defining an anchor position opening
34 at tlle apex of each scallop.
In Figure 3, a complete rectahedron shape frame
portion or sub-frame 36 is illustrated having respective
nodes 38, 40, 42, 44, 46, 48, 50 and 52. These nodes
38..i.52 Eorm the respective corners oE the rectahedron
sub-frame 36. These nodes may include a single annular
ring 37 or a pair of rings 37 and 39 welded or otherwise
connected together 6uch that the center of eacll ring
coincides and the rings are in 90 planes as shown in
Figure 8. Lengths of tension cable extend between each
node 38...52 alld form the edges of the hectatledron sub-
frame 36. For instance, spanwise cables 54, 56, 58, 60,
which are running along the direction of section 12c,
are connected respectively to their designated nodes by
means of conventional hardware pieces 54a, 72a, etc.
These hardware pieces may be any other
~2~37~
goocl state oE tlle art device Eor sucll application.
Vertical cabLe elements 62, 64, 66 and 68 are aLso con~ected
to their respective nocles. ~To name each respective node
would bur(len the present description, but the Location oE
each cable element is identi~ied in the drawings.)
Lengthwise of the overall structure, extending tension
cables 68, 70, 72 and 74 are also illustrated extending
between respective corner nodes while diagonal struts 76
(also tension cables) may be provided at diEferent locations
to reillforce selected rectahedron sub-frames. These diagonal
cable struts 76 are not essential and are used generally to
reinforce certain regions of the overall polyhedron cable
rame structure Eor good design practice to further resist
to deformations due to outside and perhaps assymetrical
loading such as wind or snow.
As is evident from Figure 3, adjacent side-by-side
rectahedron sub-frames are connected and, in fact, spanwise
cable elements 54 and ;8 are common to adjacent sub-frames
36 of adjacent sections 12b and 12c. The rectahedron sub-
Erames are connected lengthwise end to end as well withina unit section 12 and cable elements 68 and 70 are common
to two successive hectahedron sub-frames 36. The resulting
cable framework is a three dimensional bridge structure
having an overall arch shape. Each node 38, 40, 42, 44,
46, 48, 50, and 52 is connected to a respective anchor
position 34 on the anchoring skirts 30 and 32 respectively
oE each seam 26 or 28. Thus, when the envelope 11 is
inflated,the top strips 22 tend to pull apart from bottom
-- 10 --
377~S
strips 24 but are held in place by the pulling o~ th~ skirt.s
30 and 32 whicll in turn, through the anchor rings 34, pull
on the nodes of the rectahedron sub~frame inducing tensiorl
in the vertical cable elements 62, 64~ 66, 68, proporLionaLy
in~ernal air pressure and area of cross-section covered by
one such cable element. Pneumatic air pressure acting in all
directions, tension will also be similarly induced in the
spanwise cables as well as in the lengthwise cables.
ReEerence will now be made to Figures 4 and 5
which show the end conEiguration of each section. Each o~
the strips 22 and 24 are pleated near the end corners at 80
and 82 and sewn so as to give the strip an arch shape at its
ends and is sewn directly to both end panels 84, whic}l
extend along the length sides of the top and bottom panels
16 and 18 by sewing to the top strips 22 and the bottom
strips 24 respectively. The last rectahedron sub-frames 36
of the cable framework are attached to end skirts 86 and 88
which extend along the connection seam between top and
bottom panels 16 and 18 and end panels 84 respectiveLy.
The end panels 84 include loops 90 and 92 which are adapted
to receive the tubular ramp members 95 of side supports 14.
Tlle side support includes a succession of tubular frame
supports 94 and vertical stabilizer supports 96. The ends
of the supports 94 and 96 must be anchored solidly to the
ground to counteract any upward or lateral forces exerted
thereon by the envelope ll as a result o~ wind lift.
Furthermore, a large si~e tension skirt 98 may also be
~2~
proviclecl to structur<l:Lly contlect the supports 94 to Lhe
sicle eclges oE the pneumatic structure envelope. A suitnble
bracing lO0 is also provided between support members 94
ancl rallll) members 95 as well as extending flexible cabl
cross bracing 102 between adjacent support frames 94.
The en~ sections 12a an~ 12n oE the envelope ll
are closed by end caps , also made of mat~rial,
by sewing its edge to the outside edges of strips 22 and
24 by means oE a seam similar to 26 and 23 and also bearing
skirts similar to 30 and 32 to anchor to the outermost
upper and lower nodes of the cable framework respectively
to complete the air tight envelope ll.
