Glazing bar system

A system for the assembly of wall or roof panel structures which may include light-transmitting plastic panel portions. The assembly comprises two solid material splines attached to opposite faces of a panel along its margin. The resulting combination of panel and splines forms a capital I shape in cross-section, and is held in place as a sandwich system, between support members having flanges extending toward, and almost touching the panel. A preferred panel may have two thin sheets including parallel major surfaces, the sheets being interconnected and spaced apart by a plurality of web-like ribs. The support members retain the panels and provide space for attachment to other portions of a building's structural frame, or to a cable structural system.

BACKGROUND AND SUMMARY OF THE INVENTION 
The present invention relates to a system for the assembly of structural 
panel systems, and particularly to the assembly of light-transmitting 
sections such as windows, skylights and roof glazing of buildings. 
While the traditional glazing bar assembly system for light transmitting 
portions of buildings works fairly well for supporting glass, its 
disadvantages are numerous and weighty when used with transparent 
structural panels of other materials. For example, such structural panels 
may be formed as thin parallel sheets of plastic interconnected by 
parallel ribs which give stiffness and thermal insulation qualities to 
such panels. Such plastic panels are more flexible and lighter in weight 
than glass, but also have much larger thermal coefficients of expansion 
than glass. These characteristics help to make previous structures, 
incorporating such plastic panels held between rubber or rubber-like 
gaskets, supported in metal frames liable to leakage, to gasket pull-out, 
and to panel blow-out due to air pressure differences. Excessive noise is 
caused by movement of such plastic panels against gasket material in 
response to the extreme difference between the thermal coefficients of 
expansion of the dissimilar materials and because of the grasping action 
of the conventional gasketing materials on panel surfaces. Standard 
structural plastic sheet is not recommended to be used beyond a certain 
length without a mullion because of the possibility of being dislocated by 
negative air pressure differences from wind passing over the panel. 
The traditional assembly system for roof-surface portions, especially light 
transmitting portions, requires a solid structural frame system for 
support. Its disadvantages are numerous, especially in the spanning of 
very long distances, which requires large and very expensive structural 
systems. This is especially true in curved applications where the 
structural system must be preshaped in a factory and shipped in curved 
shape to the job site. 
It is one of the objects of the present invention to overcome these and 
other disadvantages and drawbacks of the prior art glazing bar systems for 
incorporation of plastic panels in structures and to provide a system 
which is simple, reliable, and relatively easily used in the field. 
It is another object of the invention to provide a structural system by 
which the plastic panel units according to the invention can be custom cut 
at a construction site and then joined edge-to-edge to form a "skin" of a 
desired width and length. 
It is another of the objects of the present invention to provide a 
weathertight structural system which is extremely light in weight, amply 
strong in tension and relatively inexpensive. 
It is another of the objects of the present invention to provide a 
structural system that may be shipped flat to the job site and assume the 
desired curved shape during assembly. 
Another object of the present invention is to provide a structure utilizing 
plastic sheets or panels and of such a design that it can extend between 
relatively widely-spaced supporting structures. 
The present invention achieves these objects by providing a glazing bar 
system incorporating a novel structural fastening arrangement for holding 
plastic panels in place. The system according to the present invention is 
a clamping bar glazing system comprising panel units having at least one 
retaining member such as a retainer strip of plastic material located 
along one margin of a face of a panel unit, and having two glazing bars, 
at least one including a flange to engage the retainer strip, with one 
glazing bar on each side of the panel, with the flange engaging the 
retainer strip to hold the panel between the glazing bars. 
In a preferred embodiment of the invention a retainer strip of plastic 
material is provided, protruding outward along the margin of a panel on 
each of the opposite sides. The glazing bars are extrusions which have 
flanges extending toward the sheet-like panel. When the resulting panel is 
engaged on both sides by the glazing bars, it is locked into its desired 
location by the flanges. 
It is a feature of the panel unit according to the invention that, using an 
abrasion-resistant, low-friction surface on the outer side of the 
projecting retainer strip, it is possible to avoid the noise created by 
the movement of the panel against a surface of different properties, 
resulting from differences of expansion and contraction. 
It is another feature of the structural arrangement according to the 
present invention that the retainer strip extending along the margin of 
the panel is a natural dam against water leakage past the juncture of the 
panel and the supporting glazing bar combination. 
It is a further feature of one embodiment of the invention that it includes 
a chamber within the glazing bar assembly where cables or other structural 
members may be located, to support the assembly as a "skin" stretched 
between retaining walls or other structural supports. 
It is a further feature of one embodiment of the invention that the 
assembly acting as a "skin" can be suspended from a cable web structural 
system by attaching suitable cables to the glazing bar assemblies. 
The present invention also provides structures for use in interconnecting 
two frame and panel assemblies perpendicular to each other to create a 
roof and removable wall system. 
The foregoing and other objectives, features, and advantages of the 
invention will be more readily understood upon consideration of the 
following detailed description of the invention, taken in conjunction with 
the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION 
Referring first to FIGS. 1 and 2 of the drawings, a "single pane" window 
assembly 30 according to the present invention includes two panels 32, 34 
which may be of extruded plastic, such as a polycarbonate or acrylic. Such 
panels may be solid, but preferably are of hollow structure with a pair of 
parallel opposite major faces 36 defined by face sheets 38, 40 joined by 
ribs 42, all of which may be produced in a desired size as an integral 
extrusion. 
The assembly 30 shown in FIG. 1 may be used as a free-standing connection 
of the two panels 32, 34. Each of the panels 32, 34 has a respective 
plastic retainer strip member 44, 46 as a retaining member, bonded to a 
marginal portion of each major face 36 of the panel preferably by a 
suitable adhesive, tape or welding system. This creates a "T" shape along 
the entire margin of each panel 32, 34. 
The two panels 32, 34 are held together by a sandwich-like securing 
assembly formed b fastening together two glazing bars 48, 50 by fasteners 
such as bolts 52, as shown in FIG. 1. The glazing bars may be of extruded 
aluminum or other material of suitable strength. Cover caps 54 of similar 
material can be snapped in place to to cover the bolts 52, as shown in 
FIG. 1. As shown in FIG. 2, each glazing bar 48 or 50 includes projections 
56 for engaging the snap-in cover cap 54. 
Each retainer member is preferably a solid member preferably of a strong, 
low-friction and abrasion-resistant material such as an ultra-high 
molecular weight (UHMW) polyethylene plastic. At least the outer surface 
58 of each retaining member 44, 46 should be of abrasion-resistant 
low-friction material such as UHMW polyethylene or PTFE to allow smooth 
movement when in contact with a surface of one of the glazing bars. The 
side surface 60 of the retaining member 44, 46, facing toward the main 
area of the panel, should be of a material able to take a hard impact 
without significant deformation. The retaining member 44 is attached to 
one of the main sheets 38, 40 by an adhesive, tape or welding system such 
as an adhesive bonding tape to bond the retaining member 44 or 46 
permanently to one of the major faces 36 of the panel 32 or 34. 
Each glazing bar 48, 50 has a middle portion 64 and a pair of wings 66, all 
preferably a unitary extrusion. Each wing portion 66 is preferably 
especially prepared to provide a very smooth planar inner panel-support 
surfaces 69 between the middle portion 64 and a respective flange 68 
extending from each of the wings 66 in a direction perpendicular to the 
glazing bar defining a panel retaining surface 71. The width 70 of each 
panel-support surface 69 is sufficient to allow ample room for the 
movement of the panel retaining member 44 or 46 toward or away from the 
middle portion 64 during expansion and contraction of the panel 32 or 34. 
The middle portion 64 provides a gutter deep enough to allow full clearance 
for the bolts 52 or other fasteners to be located below the outside edge 
of the panel, yet not so deep as to touch the middle portion 64 of the 
opposite glazing bar 50 after assembly. The middle portion 64 also is 
adequate in depth and width to serve as a receiving channel 72 for 
receiving portions of structural members of the proper width to provide 
support for the panel assembly 30 as required. 
The combination of the retaining members 44, 46 and the flanges 68 prevents 
the panels 32, 34 from being blown out of the desired position of 
engagement in the sandwich assembly, while permitting expansion and 
contraction and flexing of the panels 32, 34 in amounts greater than would 
occur in glass panels of similar size. The flanges 68 extend toward the 
major faces 36 but do not touch, so that the retaining members 44, 46, 
with their outer surfaces 58 in contact with support surfaces 69, also act 
as dams to exclude water from passing between the panels 32, 34 and the 
glazing bars 48, 50. 
While the above-described "single-pane" embodiment of the invention gives 
satisfactory service under most environmental conditions, maintaining 
particularly high temperature differentials with a minimum of losses might 
require still better thermal insulation. Such superior insulation can be 
provided by a "multi-pane" window arrangement as shown in FIGS. 3 and 4, 
using several panels 32, 34 and glazing bars 48, 50 according to the 
invention, held together by long fasteners such as bolts 74 of appropriate 
length, spaced apart along the length of such pairs of glazing bars. This 
embodiment is shown in FIG. 3 as a "double pane" or in FIG. 4 as a 
"multi-pane" assembly. 
In FIG. 3 an assembly 76 embodying the invention includes two pairs of 
glazing bars 48, 50 to form a "double pane" window and is attached to a 
structural member 78 of greater width than the panel securing assembly. A 
spacer 45 of a strong, low-friction and abrasion-resistant material with 
an "H"-shaped section may serve as an interlock as well as a spacer 
between the pairs of retainer members 44. The fasteners, bolts 74, are 
used to create a solid sandwich of the assembly. Any of various 
conventional fastening methods, including adhesives, may be used to attach 
the assembly 76 to the structural member 78. 
In FIG. 4 a "multi-pane" window assembly 82 embodying the invention is 
shown attached to a structural member 84 of the proper width to fit in the 
receiver chamber 72 defined by the middle portion of the outer one of the 
glazing bars 48. Different types of panels 32, 34 may be used, each being 
provided with retainer members 44 as described above with respect to the 
assembly 30 (FIG. 1). A spacer block 80 may be used as a stiffener as well 
as a spacer between the pairs of glazing bars 48. 
In FIG. 5 an assembly 86 of two interlocking glazing bars 88 is shown, 
together with a structural member 90 of the proper width to insert into 
the receiving chamber 92 of the glazing bar 88. In a preferred embodiment 
each of the interconnecting glazing bars 88 has a male portion 94 and a 
correspondingly located female portion 96 offset so that the bars can be 
mated with each other to provide aligned opposed channels to receive the 
respective retaining members of panels 32. The projecting male portion 94 
has an arrow-like shape seen in section view and is on a shaft of proper 
length to penetrate to the proper depth and snap into the female portion 
96 to interconnect the glazing bars 88 with the proper spacing as required 
by the thickness of the panels 32. Glazing bars of this type are joined by 
simply pushing the male and female portions into engagement with their 
respectively opposite members in an adjacent glazing bar 88, so the pairs 
of glazing bars 88 retain the panels 32 in the same way as do the glazing 
bars 48, 50. 
Although in the above-described embodiments of the panel assembly of the 
invention, the angle between the major surfaces is 180.degree., or 
parallel, with the single panels comprising a window surface thus lying in 
a common plane, in other embodiments an angle 98 will be other than 
180.degree. as shown in FIGS. 6 and 11. For example, FIG. 6 shows a wall 
100 including four panels 32 interconnected by using both free-standing 
panel-securing assemblies 30 and the structurally supported panel securing 
and holding assemblies 30. Also shown is a similar assembly joining 
adjacent panels 32 in other than a parallel plane. Such assemblies of 
panels as shown in FIG. 11 may be used to form polygons or parts thereof. 
Such polygons might even be made to approximate circles or circular arcs, 
if the width of each separate panel 32 sufficiently small relative to the 
radius of such a circle or arc. 
The retaining members of a panel 32 could also be of shapes other than the 
simple rectangular section of retaining members 44 shown in FIG. 1, if 
desired for reasons such as better weather resistance. For example, in 
FIG. 7 a pair of glazing bars 106 have flanges 108 oriented parallel to 
the panel 32, to interlock with a flange extension 110 of the retainer 
strip 111 which is also parallel to the panel. 
As shown in FIG. 8, instead of two separate retainer strip members 44 as 
shown in FIG. 1, a unitary retainer 102 is provided in a C-section shape 
which extends around the margin of the panel 32. Attachment to the panel 
32 is enhanced by the use of a recessed fastener pin 104 extending through 
the retainer 102 and the panel 32. 
The retaining member 44 could also be in more than one part. FIGS. 9a, 9b, 
10a and 10b show examples of two-part retaining members. FIG. 9a shows a 
retainer strip assembly 103 in which the solid member portion 105 is 
bonded to panel 32 and a non-abrasive member 107 defines a channel whose 
width 109 is wider than the width of portion 105. This allows more ease of 
movement in both longitudinal and lateral directions. Since there is now a 
free moving non-abrasive unit 107 between the glazing bar 48 and the panel 
32, this reduces the potential for noise. FIG. 9b shows the assembly 103 
at an enlarged scale. FIGS. 10a and 10b show a retainer strip assembly 111 
which is an interlocking version of the retainer strip 103 shown in FIGS. 
9a and 9b. The solid member 113 is wide at the base for bonding to panel 
32. It has the male dovetail interlock 115 for height in acting as a dam 
to resist rain and runoff. The non-abrasive member 117 is wider 121 than 
the solid member 113 since it is important non-abrasive surfaces 119 be in 
contact with the glazing bar 48. 
FIG. 11 shows a panel-securing and interconnecting assembly 112 used as a 
free-standing connection of two non-parallel panels. The glazing bars 114 
and 116 have respective wing portions 118, 120 oriented at the appropriate 
angles to their middle portions 122, 124 to align the panel supporting 
surfaces 126 parallel to each other and align the flanges 68 opposite each 
other. A fastener such as a bolt 128 holds the glazing bars 114 and 116 
together to retain the panels 32. 
Referring now to FIGS. 12a and 12b, a panel connecting assembly 130 
according to the invention is shown used as a rake for the connection of a 
roof panel 32 to a wall panel 132. A pair of rectangular solid members 134 
are bonded to the respective main faces 136 along the margin of the wall 
panel 132. The wall panel 132 can be inserted into the receiver channel 
138 of the glazing bar 140 and attached by fasteners such as screws 142, 
regardless of whether the glazing bar 140 be straight or curved. A further 
strengthening of the assembly 130 is achieved by bonding metal strapping 
145 to the glazing bar 140 whether in a straight run or in a curve. This 
serves as a flange to assist in retaining the solid members 134 and panel 
132. A filler member 144 is used in the channel of the assembly between 
one pair of wings of the pair of glazing bars 140, instead of a further 
extending panel margin. FIG. 12b shows a segmented filler 144. By using 
thinner segments, the unit can be shipped flat to the project site then 
field bonded with a very highly adhesive bonding tape 143 in a curved or 
flat shape. This avoids the need for preforming structural elements before 
shipping, avoids the shipping of an awkward shape, and allows custom 
assembly in the field to match the existing conditions. This is further 
illustrated in FIG. 13 where the thin strips 147 preferably are of 
suitably strong metal and are located either within the receiving chamber 
72 of the glazing bar 140 or bonded to the exterior of the assembly 30. 
Again, this shows the structural member to be shipped flat and then field 
assembled in a laminated form with a flat or curved shape held by a 
suitable adhesive bonding tape 143. This avoids preforming of structural 
members, avoids shipping of awkward shapes, and allows custom assembly in 
the field to match the existing conditions. 
FIGS. 14a, 14b and 14c show various ways in which adjacent ends of segments 
of retaining members 44 may be overlapped to allow, if necessary, for a 
difference between the thermal coefficients of expansion of the retainer 
members 44 and the material of a panel 32 to which such a retainer member 
is attached. Thus, in FIG. 14a opposite side portions 146 and 148 are 
overlapped longitudinally, and transverse portions 150 and 152 extend 
toward the overlapped portions 146 and 148. In FIG. 14b end portions 154 
and 156 are diagonal and overlap. In FIG. 14c end portions 158 and 160 
have a simple scarf joint. 
Referring next to FIG. 15, three panels 162a, 162b and 162c are connected 
as panel assemblies 164 of glazing bars 166 with a cable 168 extending 
longitudinally through a cavity defined by each pair of glazing bars 166 
to provide tensile strength for support of the panels and glazing bars. In 
a typical application of this embodiment of the invention, as shown at a 
larger scale in FIG. 16, the panels 162a and 162b will be held in tension 
with the retaining members 170 held tight against the flanges 172 of the 
glazing bars 166. The cable 168 or other structural material will be 
connected to a suitable supporting structure to carry the weight of the 
entire assembly of panels and glazing bars and to support loads imposed by 
weather conditions, as an enclosing "skin." The panel assembly 164 
consists of two panels 162a, 162b, etc. which will usually, but not 
necessarily, be of plastic. A sandwich effect has been achieved by joining 
two glazing bars 166 by the use of fasteners such as bolts 174 which 
extend through faces 176 of the glazing bars located on a level above a 
gutter 178 intended to provide for drainage. In FIG. 17, an oblique 
sectional end view of one of the glazing bars 166 provides a better 
understanding of this "skin" assembly embodiment of the invention. Four 
flanges 180 fall in a common mating plane 182 between the middle pair of 
flanges. Flanges 180 are all located so that when mated they just keep the 
margins of the perpendicular flanges 184, corresponding to flanges 68 of 
the glazing bar 48, from coming into contact with the major faces 186 of 
the panels 162a, 162b when the surfaces 188 or 190 of the retaining 
members 192 and 194 are in contact with the respective interior surface 
196 of the glazing bar assembly. An inner surface 198 of each flange 184 
is desirably prepared to be flat and very smooth. This facilitates 
longitudinal movement of the panel margins within the channels defined by 
the flanges 184 as expansion and contraction of the panels occur. 
A chamber 200 is provided between the two glazing bars to receive the cable 
168. 
FIG. 18 is a sectional end view of an extruded plastic structural panel 
162a for use in a tensioned skin panel assembly which is an embodiment of 
the invention. The panel 162a may be extruded with its retaining members 
192, 194, corresponding functionally to the retaining members 44, in solid 
form as is retaining member 192, or in web form as is retaining member 
194. Panels 162a may be extruded of one material or co-extruded of two or 
more plastics. The surfaces 188, 190, 202, 204, 206 and 208 should be of 
abrasion-resistant and preferably low-friction material to be able to 
slide freely along the interior surfaces 196 and 198 of the glazing bars 
166. Such surface materials may be co-extruded, applied to the panel or 
the glazing bar. Major face sheets 210 are interconnected and spaced by a 
plurality of ribs 212 which divide the space between the two major face 
sheets 210 into a plurality of subspaces. All of these elements form a 
truss-like structure of which the two major face sheets 210 constitute the 
chords and the ribs 212 constitute the webs. 
FIG. 19 shows one manner of interconnecting a panel assembly 164 of the 
tension-bearing "skin" configuration as a roof portion to a panel assembly 
30 as shown in FIG. 1, used as a wall section 213. By the use of removable 
fasteners such as bolts 214, longer than bolts 174 shown in FIG. 16, the 
wall section 213 can be permanently or removably attached to the roof 
portion. Hook-like extruded connectors 216 are bolted to the glazing bars 
166 and engage flanges 68 of one pair of wing portions of the glazing bars 
48 of the wall panel assembly 30. FIG. 19 also shows an optional bracket 
217 to be used when a cable 168 needs to be larger than the internal 
chamber 200 will accommodate. Projections 219 keep the cable from coming 
in contact with the bolts 214. 
FIG. 20 shows the addition of a suspension cable connection to the panel 
assembly 164 shown in FIGS. 15 and 16. A bracket 218, which may comprise a 
pair of opposing extruded side portions, is attached at the proper 
position by fasteners such as bolts 214 extending through suitable holes 
in the bracket 218. A six-edged cable end fitting 220, or the equivalent, 
is used to retain the end of the cable 222 in the bracket 218. 
FIG. 21 shows a self-supporting panel structure 224 built in accordance 
with the invention with panels and glazing bars, such as the panel 
assemblies 30 of FIG. 1, in a free-standing mode, with the glazing bars 
bent about an axis transverse to the length of the glazing bars and 
panels, before the glazing bars of each pair are interconnected to retain 
the panels. The free-standing system is an assembly of several such 
parallel glazing bars and panels, and may include structural members in 
receiving channels 72 defined by the glazing bars of the panel assemblies. 
Respective ends of the glazing bars 48 are firmly attached to structural 
support forms 226. 
FIG. 22 shows a somewhat similar structure 228 in which panel assemblies 
embodying the invention of either the type shown in FIG. 1, or the type 
shown in FIGS. 15, 16, are partially supported by depending vertical 
suspension cables 222. Respective depending cables 222 supporting glazing 
bar and panel assemblies are supported by a main cable 232. 
FIG. 23 shows panel assemblies 164 such as those of FIGS. 15 and 16 in use 
in the cable supported mode as a tension "skin". The system composed of 
panel assemblies 164 and panels 162a, optionally with or without 
structural members in respective chambers 200, is firmly attached to 
structural forms 234. The system is further supported by fastening a cable 
222 (see FIG. 20) to the panel assemblies 164 and to a main cable 232. 
In FIGS. 24 and 25 system of tensional panel assemblies according to the 
invention is shown in simplified views in use as a cable supported, draped 
roof structure 236. The roof structure 236 comprises several panel 
assemblies 164 as shown in FIGS. 15 and 16, with or without structural 
members such as cables 168 in their chambers 200, as required by the size 
of the structure 236 and the area to be spanned. The lower end lower 
portions 238 of the structure 236 are firmly attached at the base to 
retaining structural forms 240. The upper ends 242 of the panel assemblies 
164 are supported by fastening them to a generally horizontal main 
suspension cable 244 by a suitable clamp (not shown). This allows the 
panel assembly system of the roof structure 23 to act as a "skin" between 
the retaining base structure 240 and the main cable 244. The use of cables 
168 in chambers 200 of the panel assemblies 164 allows the structure 236 
to act as a structural system in tension between the retaining structure 
and the main cable 244. 
In FIG. 26 a similar embodiment of the invention is shown as a roof 
structure 246 in the "drape" mode between a vertical wall 248 and attached 
at the base to structural forms 250. This allows the system to act as a 
"skin" between wall 248 and base structure 250. 
As shown in FIGS. 27 and 28, the glazing bar and panel assemblies 164 of 
the present invention such as shown in FIGS. 15 and 16 may be assembled to 
form a skin 252 for a dome-like structure, stabilized and supported by a 
main cable 254 stretched between two supporting tower-like structures 256 
and anchored as at 258 with cables 260. Properly spaced depending support 
cables 262 are fastened to the main cable, and to the glazing bar and 
panel assemblies 164 (see FIG. 20). The glazing bar and panel assemblies 
164 (see FIGS. 15, 16), with or without cables 168 or other structural 
members in the chambers 200, are firmly attached at the base to a 
structural ring 264. The effect is to create a dome-like light-weight 
"skin" cover between the edges of the structural ring 264. 
While the assemblies 30, 76, 164 and the like of glazing bars 48, 88, 166 
and panels 32, 34, 162a, 162b and the like having retaining members 44, 
46, 103, 111 and 170 and the like according to the invention are primarily 
meant to serve for light-transmitting wall or roof portions and are 
therefore designed to include plastic panels, the special properties of 
these assemblies such as their thermal (as well as acoustic) insulation 
effect, the ease with which larger panel surfaces are assembled, and their 
relatively low cost, suggest their use also for non-transparent walls, 
partitions, etc. 
The terms and expressions which have been employed in the foregoing 
specification are used therein as terms of description and not of 
limitation, and there is no intention, in the use of such terms and 
expressions, of excluding equivalents of the features shown and described 
or portions thereof, it being recognized that the scope of the invention 
is defined and limited only by the claims which follow.