Note: Descriptions are shown in the official language in which they were submitted.
21 274 fig
ARCHITECTURAL PANEL SYSTEM FOR
GEODESIC-LIKE STRUCTURES
BACKGROUND OF THE INVENTION
This application is related to U.S. Patent
No. 4,958,476 filed May 19, 1989.
The present invention concerns architectural
structures, and more particularly, relates to an
architectural panel system for forming covers or
shelters in the nature of geodesic-like structures. Such
structures are used for various purposes, including
radomes, storage facilities, housing and public
buildings.
Geode:;ic-like structures are well known. An
example of one is described in U.S. Patent No. 2,682,235
to R. Buckminsi~er Fuller. It has long been desired in
building such structures and frames to obtain maximum
strength and space with a minimum of materials. It has
been a further .goal t:o simplify the structures as much as
possible for easier and less costly construction.
The object of the present invention is to
provide an architectural panel system for constructing
geodesic-like structures of various shapes and sizes that
achieve a higher strength with a simpler and less costly
construction than heretofore known.
_... __.._~~.~w=....~... _. _ _... _W.__.._..~.~..~_._.. ..
__._..._..~.,_."~_~._..___..._ ._.. _. _._.____~.__.___..
WO 93/14277 PCT/US93/00122 ~ t
~1~7 4Ei9 2
SUMMARY OF THE INVENTION
Boiefly, and in general tenas, the present
invention provides an architectural panel system that is
ideally suited to the assembly of geodesic-like structures
with corrugated panels of relatively thin material that
are inexpensive, lightweight and easy to assemble in a
variety of shapes and sizes for diverse uses, yet exhibit
a high resistance to pressure-loading forces such as
caused by wand or snow.
More specifically, the present invention resides
in an architectural panel system in which three or more
corrugated panels are joined along their sides to form a
polyhedral angle. This basic structure can serve as a
cover itself , or it can be used as a unit for a larger
geodesic-lit";e structure made up of any number of similar
units formed of panels joined together in like manner
along their edges to each other and to other units.
Numeroua different spherical and non-spherical
geodesic-li)';e structures can be assembled from
appropriate7~y shaped panels with this architectural panel
system. TIZe shapes of the corrugated panels may be
triangular, rectangular, pentagonal or other regular or
irregular polygonal configurations. The panel surfaces
themselves may be flat or curvilinear.
Tree corrugations on individual panels may be
formed in the panel surface or along side flanges provided
for attaching adjoining panels together, or both. Surface
corrugations may extend only partially or substantially
all the way across the panel surface, depending on the
requirement: of the particular structure, to increase the
'r'~" 93/14277 ~ ~ ~ ~~ ~ PCT/US93/00122
3
surface stiffness of the panel and its resistance to
pressure loading. Complementary corrugations formed in
the side flanges of adjoining panels may nest and serve to
interlock the panels together with appropriate fastening
means to provide added strength and ease of assembly.
Corrugations in the panel surface may be formed
in any number o:E useful patterns. For example, in a
presently ~~referned embodiment, the corrugations in the
surfaces of triangular and pentagonal panels for a
spherical ~~eodesic-like dome are formed substantially
perpendicular to the edges of the panels to enable the
side corrug~ation:a to be formed uniformly. Because the
edges of these ~>anels follow a geodesic line along an
equator of the ~;pherical dome, the corrugations follow
paths which conva_rge as longitudinal lines to the pole
normal to that equitorial plane, such that the
corrugations themselves converge on the panel along lines
which in ei°fect divide the panel surface into as many
segments as it has sides. To eliminate unfavorable stress
concentrations where the surface corrugations converge and
distribute stresses, grooves can be formed in the panel
surfaces along those lines of convergence from the corners
of the panel to its center. Surface corrugations in
parallelogram-shaped panels, on the other hand, can be
formed diagonally across the face of the panel without
creating undesirable non-uniformities in the side
corrugations. In addition, corrugations in the panel
surface and along the side flanges advantageously may be
intercorrugated relative to one another for more strength
and stiffne:~s.
The side' flanges of the architectural panels may
be fastened together directly with rivets, screws,
adhesive bonding or in any other suitable manner, or by
WO 93/14277 PCT/US93/00122
~1~~ g~69
4
use of separate interlocking members for greater
mechanical integrity and weatherproofing. For example,
the interlocking members may take the form of channels
into which the nested corrugations of adjoining side
flanges are received and fastened. A multi-legged channel
may be provided to fasten and reinforce the corner
junctions of the side flanges of the panels at the vertex
of the polyhedral angle, with a separate channel radiating
from a centerpoint to receive each pair of adjoined side
flanges. A single-legged channel may be provided to
fasten and reinforce each pair of side flanges along
substantially their entire length between vertices. In a
further refinement, the single-legged channels may be
joined at one or both ends to the multi-legged channels at
the vertices of the polyhedral angles for yet greater
mechanical integrity. The channels can serve to seal the
junctions between adjoining panels and possibly carry off
any water that penetrates the junctions.
The corrugated construction and strong,
interlocking junctions of the panels enable use of very
thin-wall panels, which are preferably formed using
polycarbonate plastic material. The resulting geodesic-
like structures are inexpensive, lightweight, easy to
construct, weatherproof, and exhibit high strength against
pressure loading forces, and are ideal as radomes, covers
for storage tanks, and a wide variety of shelters.
The novel features which are believed to be
characteristic of the present invention, together with
further objectives and advantages thereof, will be better
understood from the following detailed description
considered in connection with the accompanying drawings,
wherein like numbers designate like elements. It should
be expressly understood, however, that the drawings are
V~ 93/14277 ~ ~ ~ ~ PCT/US93/00122
for purposes of illustration and description only and are
not intended as a definition of the limits of the
invention.
5
WO 93/14277 PCT/US93/00122 -
DESCRIPTION OF THE DRAWINGS
The accompanying drawings illustrate, by way of
example, presently preferred embodiments of the invention,
in which:
FIG. la is a side elevation of one embodiment of
a geodesic-like structure formed by corrugated
architectural panels having a pentagonal shape in
accordance with the present invention;
FIG. lb is a plan view of one panel from the
structure in FIG. la;
FIG. lc is a side view of the panel in FIG. lb;
FIG. id is a partial cross-sectional view of the
panel taken along the line A-A in FIG. lb;
FIG. le is a partial cross-sectional view of the
panel taken along the line B-B in FIG. lb;
FIG. 2 is a perspective view of another
embodiment of a corrugated pentagonal panel suitable for
use in the geodesic-like structure in FIG. la;
FIG. 3a is a perspective view of one embodiment
of a multi-legged, trefoil interlocking channel member in
accordance with the invention;
FIG. 3b is a perspective view of one embodiment
of a single-legged interlocking channel member;
FIG. 3c is a partial perspective view of two
W" 93/14277 ~ ~ ~ PCT/US93/00122
7
nested corrugated side flanges of adjoining panels mounted
in a portion of an interlocking channel member;
F'IG. ~~ is a perspective view of another
embodiment of an architectural panel having a triangular
shape suii:able for assembly into a geodesic-like
structure;
FIG. 5 is a perspective view of yet another
embodiment of a corrugated panel having a rectangular
shape suitable for assembly into a geodesic-like
structure;
FIG. 6a. is a plan view of a triangularly-shaped
corrugated panel similar to the panel of FIG. 4 suitable
for assembly into a geodesic-like structure;
FIG. 6b is a front elevational view of the panel
in FIG. 6a;
FIG. 6c is a side elevational view of the panel
in FIG. 6a;
F:IG. 6d. shows the edge detail of the panel in
FIGS. 6a - 5c;
F:CG. 6e is a partial cross-sectional view of the
panel taken along the line A-A in FIG. 6a;
F:CG. 7a. is an illustration of an icosahedral
geodesic-lilce dome formed by an assembly of twenty
equilateral triangular panels; and
FIG. 7b is an illustration of a larger, eighty
section polyhedral dome in which each icosahedral
WO 93/14277 PCT/US93/00122
8
triangular section in FIG. 7a has been further divided
into four triangular sections.
CA 02127469 2000-10-06
WO 93/14277 ~PCT/US93/00122
9
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, and particularly
FIGS. la - le thereof, there is shown an illustrative
truncated spherical antenna cover or radome 10 formed by
the joinder of eleven identical architectural panels 12,
giving the structure a dodecahedral form, in which the
bottom five panels have been trimmed for mounting to a
foundation (not shown). The surface 14 of each panel 12
has a generally pentagonal shape and is bounded along its
edges by side flanges 16 that are formed perpendicular to
the panel surface. The intersection of any three panels
12 in a vertex 18 may be considered to form a polyhedral
angle, although in this particular embodiment the panels
have a generally curvilinear rather than a flat surface.
The radius of curvature of the panels 12 is the same as
that of the dome 10. The curvilinear shape of the panels
12 helps to stiffen their surfaces.
The surfaces 14 of the panels 12 have
corrugations 20 to increase the strength and stiffness of
the panels. In FIGS. la - lc, the surface corrugations 20
extend only a small way into the panel surfaces 14 from
their edges, leaving the remainder of the panel surfaces
smooth. The side flanges 16 also have corrugations 22~ to
facilitate manual assembly of the panels 12 and add
strength to the cover 10. As seen in FIG. la, the
corrugations 22 in each side flange 16 nest with the
corrugations in an adjoining side flange to form strong,
interlocking junctions. The panels 12 use the innovative
intercorrugation structure disclosed in my co-pending US
Patent 5,077,949, of January 7, 1992. That is,
corrugations 20 in the panel surface 14 are intercorrugated
with the corrugations 22 of the side
WO 93/14277 PCT/US93/00122
l0
flanges 16. (See FIGS. ld and le.) These
intercorrugations add to the mechanical strength and
function of the cover 10. The panels can be made of any
suitable material, including metal, although for most
applications it is presently preferred to make them of a
polycarbonate plastic material by vacuum forming
techniques.
A structure such as cover 10 is assembled by
simply mating the side flanges 16 of adjoining panels 12
and fastening them together by any suitable means, such as
rivets, screws or adhesive bonding. Alternatively, T-
shaped interlocking channel members in both multi-legged
and single-legged .configurations 24 and 26 shown in FIGS.
3a and 3b, respectively, are provided into which the mated
side flanges 16 may be received and fastened.
The multi-legged channel member 24 is formed as
a trefoil in which each of three channels 28, 30 and 32
radiate from a common center point at the same angles and
with the same curvature as the intersecting panels 12
which form the polyhedral angle. Of course, it will be
appreciated that in the case of structures employing more
than three panels to form a polyhedral angle, additional
legs in the appropriate configuration can be added as
needed . The free end of each channel 2 8 , 3 0 and 3 2 has
holes 34 formed laterally through its sidewalls 36 to
receive a rivet or screw to hold the mated side flanges 16
near the vertex 18 and reinforce the corner junction of
the panels 12. The bottom walls 38 of the channels 28, 30
and 32 extend laterally beyond the sidewalls 36 for added
strength.
The single-legged channel member 26 is a simple,
elongated channel with holes 40 through its sidewall 42
~ 93/14277
PCT/US93/00122
11
for rivets or screws spaced along its length and a bottom
wall 44 that :Likewise extends laterally for added
strength. :It may be used to secure the mated side flanges
16 of adjoining ;panels 12 together between vertices 18.
As shown in FIG. 3b, the single-legged channel member 26
similarly is curved to complement the curvature of the
adjoining side flanges 16.
Alternating ends 46 and 48 of the multi-legged
and single-:Legged channel members 24 and 26, respectively,
are flared ~to receive unflared ends 50 and 52 of adjacent
channel members. In this way, all of the channel members
in the cover 10 may be joined together by the same rivets
or screws h~~lding mated side flanges 16 in place. These
channel members 24 and 26, when joined to the side flanges
16 and to each other, form a stiff, monocogue structure.
In addition to joining the side flanges 16
together, tree interlocking channel members 24 and 26 serve
to weatherproof junctions between adjoining panels 12. In
this regard,, it c,an be noted that the bottom edges of the
mated side i:lange;s 16 can abut the bottom walls 38 and 44
of the channels 24 and 26, respectively, or alternatively
the channel~~ can be formed sufficiently deep that adequate
free space remains between the bottom edges of the side
flanges and the bottom walls of the channels to serve as
ducts to carry off' any water that penetrates the junctions
between ad=joining panels 12. As with the panels
themselves, the channel members 24 and 26 can be formed of
any suitable material including metal or plastic.
Turning to FIG. 2, there is shown another
possible form of a pentagonal architectural panel 54
having a curvilinear surface that is suitable for the
geodesic-lilt:e dome 10 of FIG. la, in which substantially
WO 93/14277 PCT/US93/00122
~.'~'~ 46 9
12
the entire surface 56 and the side flanges 58 of the panel
are corrugated. The surface corrugations 60 are formed
substantially perpendicular to the edges of the panel 54.
This enables the side corrugations 62 to be formed in a
uniform size and pattern along the side flanges 58.
By referring back to FIG. la, it will be
appreciated that each of the edges of these panels 54
follows a geodesic line along an equator of the dome 10.
Therefore, the surface corrugations 60 follow paths which
converge as longitudinal lines to the pole that
corresponds to that equitorial plane. Hence, the
corrugations 60 themselves converge on the panel 54 along
lines which extend from the corners of the panels to their
centers. It has been determined that if the surface
corrugations 60 were permitted to meet, unfavorable stress
concentrations and possible buckling of the panel 54 could
occur under load of pressure forces from wind or snow or
the like. To alleviate this potential problem, load
distribution grooves 64 are formed in the panel surface 56
along these lines of convergence as a stiffening junction
between the converging surface corrugations 60.
FIGS. 4 and 6a - 6e show equilateral triangular-
shaped panels 66 and 68, respectively, which may be used
to form an icosahedral geodesic dome 70, as illustrated in
FIG. 7a. The geodesic dome 70 of FIG. 7a has a spherical
shape formed by joining twenty such triangularly-shaped
panels. The panels 66 and 68 have corrugations both in
their surfaces 72 and 74, as well as in their side flanges
76 and 78, respectively. The corrugations 80 and 82 in
the side flanges 76 and 78, respectively, are
intercorrugated with the corrugations 84 and 86 formed in
the panel surfaces 72 and 74, respectively, and nest with
corrugations in side flanges of adjacent panels. As with
V~"" 93/14277 ~ ~ ~ ~ ~ PCT/US93/00122
13
the pentagonally-shaped panel 12 of FIGS. la - le, the
side flange:a 76 and 78 of these triangular panels 66 and
68 can be fastened directly together or through use of
interlocking channel members similar to those shown in
FIGS. 3a - :3c.
L:lke the pentagonally-shaped panels of FIGS. la
- le and 2, the edges of the triangular panels 66 and 68
shown in FIGS. 4 and 6a - 6e follow geodesic lines. See
FIG. 7a. Likewise, the surface corrugations 84 and 86 are
formed perpe:ndicu:lar to the edges of the panels 66 and 68
such that they follow longitudinal paths and converge
along lines extending from the corners of the panels to
their centers. Load distribution grooves 88 and 90,
respectivel~~, shown in cross-section in FIG. 6e, are
formed along these convergence lines to avoid stress
concentrations and better distribute stresses in the
panels under load ~.
In the ease of antenna covers, very thin radome
walls are essential to low loss, broad band, microwave
transmission,. An 80-inch radome with a peak-to-valley
surface cor~.-ugati~on depth of 0.625 inches was designed
with the panels of FIG. 6a - 6e having a nominal material
thickness of 0.020 inches made from LEXAN brand
polycarbonate plastic by General Electric Company. By
critical selection of an included angle O of 60 degress
for the load distribution groove 90 (FIG. 6b) and an
included angle O of 90 degrees for the surface
corrugations 86 (:EIG. 6d), analyses show that the panel
should withstand a pressure equal to a wind of 150 mph
without tackling with a safety factor of four to five.
For radome applications, it will be appreciated
that it is desirable to utilize very thin panels and
WO 93/14277 PCT/US93/00122
14
maintain all corrugations and load distribution grooves
shallow to minimize insertion losses and avoid inhibiting
radiation propagation. Although different design
considerations may control in other applications, such as
storage facilities, the architectural panel system of the
present invention is still advantageous in permitting use
of light, thin and inexpensive panels that are easy to
assemble into the desired structure.
If the radius of a structure becomes very large,
the equilateral triangular sections of an icosahedral type
dome may be too large to handle conveniently, compared to
smaller sections of an equally large polyhedral dome
having, for example, eighty sections. As indicated in
FIG. 7b, the eighty sectioned polyhedral dome 92 would be
formed by dividing each icosahedral triangular section
into four triangular sections. This would be done by
connecting the mid points of each leg of a triangular
icosahedral section (A, B, C) in FIG. 7a with a geodesic
line. Thus, there are formed three identical isosceles
triangular sections and one equilateral triangular
section. Each new triangular section has approximately
one fourth the area of the original icosahedral section
and about the same area as the icosahedral section of a
spherical dome with half the radius. This process of
dividing panels of a polyhedral geodesic form is described
in the works of R. Buckminister Fuller as increasing the
frequency of a polyhedral form.
Repeating the process on panel sections of very
large polyhedral domes, therefore, is a logical procedure
to maintain convenient dimensions for its panel sections.
Thus, geodesic dome, thin-wall panels, with manageable
dimensions can be designed regardless of the overall dome
dimensions. Moreover, the general corrugation pattern in
Vu~' 93/14277
PCT/US93/00122
triangular panel sections used in the higher frequency
polyhedral domes will follow the geometric and structural
principles illustrated by the panels shown in FIGS. 4 and
6a - 6d.
5
FIG. 5 shows a parallelogram type of panel 94
that is rectangular in shape with corrugations 96 in the
panel surface 98 and side flanges 100 with corrugations
102 for interlocking adjacent panels. Unlike the
10 triangular and pentagonal panel shapes, however, the
surface corrugations 96 on this rectangularly-shaped panel
94 can be formed diagonally relative to the edges of the
panel withoist creating distortions or non-uniformities in
the corrugations 102 of the side flanges 100. Panel 94
15 has the advantage of being easier and less expensive to
manufacture by 'virtue of its uninterrupted diagonal
surface corrugations.
I1. will be understood, of course, that
modifications of t:he present invention will be apparent to
others skil7.ed in the art. Consequently, the scope of the
present invention should not be limited by the particular
embodiments described above, but should be defined only by
the claims :yet forth below and equivalents thereof.
