Translucent roofing means

Roofing means including a roof panel. Means are provided for securing the roof panel onto a roof frame including elastic clamping means joining the panel in tensioned relation to the frame and a deformable elastic sealing member secured between the clamping means and the panel and covering the clamping member. The roof panel may be a thin translucent plastic sheet.

This invention relates to translucent roofing means, and more particularly 
to translucent plastic roof panels. 
In solar heated houses there is sometimes a need for a translucent roof 
which will admit sunlight freely while excluding rain and air 
infiltration. Glass, is fragile, heavy and more costly material than 
certain plastics like fiberglass-reinforced polyester, which are tougher, 
lighter, less expensive and have a pleasing non-specular surface. When 
subjected to normal loads from wind pressure or snow, however, a plastic 
panel deflects out of a plane and the distance between its edges draws 
together a little. If such a panel is sealed at its edges to a rigid frame 
this action can break the seal and cause leaks to develop. At the same 
time, the panel and the frame would conveniently be made of materials 
having different coefficients of thermal expansion and different 
dimensional response to moisture, and are frequently exposed to quite 
different temperatures, which causes additional working of the sealed 
edges. 
A thin plastic panel has little plate strength, but it can support very 
substantial pressures as a membrane if it is stretched like a drum head or 
trampoline and the edges are allowed to pull in when the surface bulges 
out of a plane. 
From the preceding brief analysis it becomes clear that tough, relatively 
thin, translucent plastic panels are preferred for glazing a transparent 
roof. Also, the panels should be secured to the rigid roof frame by 
elastic members which will subject the panels to tension but will permit 
them to bulge under pressure loading or expand under temperature changes 
without relative motion in the edge seals. 
Accordingly, it is a primary object of this invention to provide a 
practical, aesthetically pleasing translucent roofing system which 
withstands normally encountered extreme ambient temperature cycling, 
positive and negative wind pressure fluctuations, snow loads and shock 
loads from hail and incidental dropped or thrown objects while durably 
sealing against entry of wind and rain water. 
It is another object of this invention to provide a translucent roofing 
system which can be assembled on site rapidly by a step-by-step process 
without the use of special tools or special skills; and can be readily 
disassembled if corrections or panel replacements are required. 
It is a very important secondary object to provide a translucent roofing 
system constructed of low cost parts within the range of well developed 
fabrication technology. 
Another object of this invention is to provide roofing means comprising a 
roof panel, means for securing the roof panel onto a roof frame comprising 
elastic clamping means joining said panel in tensioned relation to said 
frame and a deformable elastic sealing member secured between said 
clamping means and said panel and covering said clamping member.

In FIG. 1, translucent plastic panels 1, are shown secured to roof beam 2, 
by clamping members 3. These clamping members are secured to the beam by 
ring nails 4. The panels are frictionally secured in the clamping members 
by wire splines 5. Rain water is excluded by an elastic seal strip 6. A 
lag bolt 7, penetrating the seal strip, may be screwed into the beam to 
act as a lug, for supporting a ladder to facilitate maintenance of a 
sloping roof. 
Athough for illustration the roof system is shown in conjunction with 
wooden framing members, adapting it to framing members of other materials, 
of steel, aluminum, plastics or concrete, for example, would be obvious to 
those skilled in the art. 
The clamping member 3, is preferably of metal having substantial strength 
and resilience, and may be of low carbon steel strip about one-sixteenth 
of an inch thick. Since the clamping member is completely sealed from 
outside weather, it is not necessary to galvanize, electro-plate or paint 
it for protection against corrosion. 
The clamping member is bent into a contour having an approximately 
90.degree. bend at 31, and a 180.degree. bend producing a channel 32 of 
controlled inside spacing which clamps the panel 1, and the wire spline 5 
tightly. A wider overhung channel 33 accepts and retains the edge bead of 
the seal strip 6. 
The clamping member 3 is provided with one or more perforations 34, for 
nails 4, attaching it to the beam 2. Since the panel length expands and 
contracts differently than the beam 2, the holes 34 are slotted, as shown 
in FIG. 2. Each hole may have a central notch 39 for conveniently 
centering the nails at assembly. 
Before assembly the clamping member 3 is prebent to a substantially curved 
contour 35. Thus, when the nails 4 are driven it is elastically flattened 
and springs tightly against the beam. The flange 36 serves to reinforce 
the lower edge of the clamping member so that the nails may be spaced 
apart without serious longitudinal buckling of the clamping member. Clamp 
3 may also be used to retain a solar collector or other device (not 
shown), which one wishes to hold in fixed relation with the translucent 
panel. 
As illustrated in FIG. 4, the lower middle wall of the channel 32 may be 
provided with ridges or serrations 304 which are pressed into the plastic 
surface of panel 1 when the spline wire 5 is forced into place. This 
prevents the panel from working out of the channel under repeated 
temperture cycling which causes slight differential movement between the 
metal clamping member 3 and the plastic panel 1. 
It will be evident to those skilled in the art that the contour of this 
clamping member can be economically produced by known techniques of 
stamping, brake forming, or preferably roll forming from metal strip. 
The seal member 6 is extruded from an elastomer which can withstand outdoor 
weathering, sunlight, ozone, and the expected outdoor temperature range 
without losing its elasticity. Silicone rubber is one such material. It 
consists of a tough web section 63 bordered by edge beads 61 and 62 which 
have accurately sized sections. 
FIG. 2 shows how a roof may be constructed using this roofing system, 
especially how expansion may be accommodated and weatherproof joints may 
be made with roofing at the top and bottom edges of a panel. 
The clamping member 3 may have a different coefficient of thermal expansion 
than the panel 1. Therefore, to restrict relative motion of the clamping 
member and the panel where they are frictionally secured together, the 
clamping member is preferably less than two feet long. To hold a long 
panel, a plurality of clamps is required, initially spaced apart by spaces 
such as 303 to allow for differential expansion of the panel and the beam. 
These gaps should be 1/8 inch or less because although the panel is 
continuous, the seal bead 61 is less completely confined there and the 
stiffness of the seal is relied upon to make a continuous contact with the 
panel. 
At the upper and lower ends of the panel, the roof framing includes wooden 
bridging members 21 and 23, and the roof is sheathed with plywood 22 and 
24, covered with built-up roofing 101. Clamping members 301 and 302 are 
secured to the cross-members 21 and 23 by nails. They may be identical to 
clamping members 3. Notching the flange 36 at both ends of each clamping 
member, as at 305, prevents interference of the flanges at the corners. 
The upper and lower elastic seal members 601 may be formed from seal strip 
6 by slitting off one edge bead, such as 62. The remaining edge bead is 
secured against the panel by the cavity 33 of the clamping member, and the 
web 63 of the seal is layered under the roofing 101, at the top in 
water-shedding flashed relation, and secured to the roof sheathing by 
roofing nails 41. Mastic roofing cement is used to make the joint 
water-tight. 
Of course one-bead seal members of any desired width could be used instead 
of cut-down two bead seals for making these joints to the roofing. Similar 
seals interleaved with roofing may be used on the sides of the translucent 
opening. 
At the lower end of the panel the nails 42, securing the clamping member 
302, are not tightly driven, but are sufficient to restrict motion of the 
panel toward or away from the roof. This allows for assembly, as will be 
described, and also permits the larger differential motion expected at the 
end of a long panel. The web portion of the seal is interleaved under the 
top layer of the roofing, again in water-shedding, flashed relation, and 
secured with nails and roofing cement. 
To assemble a roof according to this roofing system, the craftsman first 
nails a series of clamping members to the sides of the roof beams around 
the openings to be glazed. The channel portion 32 of the clamping members 
may be rested against the edge of the beam to gauge the location of the 
clamping members. Temporary spacers may be placed against the edge of the 
beam between the clamping members to space them elastically about 1/16 
inch from the beam for assembly of the translucent panels. 
The precut translucent panel is next flexed to slip into the channels 32 of 
the clamping members along the sides and then slid upward into the channel 
of the upper end clamping member 301. The channel of the lower clamping 
member is then slipped over the lower edge of the panel, and this lower 
clamping member is temporarily secured in place. The spline wire 5 is now 
forced into the channel firmly securing the edge of the panel to the 
clamping members. When the panel is secured in place, the temporary 
spacers, etc. restraining the clamping members are removed. 
The seal strips 6 are applied over the beams by forcing the edge beads 61 
and 62 into the overhung channels 33. Ends of the strips are trimmed to be 
leaved with the roofing as indicated in FIG. 3. The seal strips 601 at the 
ends of the panels are similarly assembled, and are trimmed at the ends to 
make a sealable joint with the seal strips 6 along the beams. Final 
closure of the corner joint is by means of a bead 602 of elastic sealant 
cement which may be silicone rubber sealant. Layered roofing is then 
completed in the adjacent areas and secured by nails and roofing cement. 
If a panel or a clamping member is damaged or incorrectly assembled, it can 
be disassembled from the roof without disturbing the other panels. The 
seal bead 61 is first stripped out of the overhung channel 33. Then the 
wire spline 5, which can be reached at the ends of the clamping members 
and at the spaces 303 between them, is stripped out of the channel 32. 
Then the panel can be flexed and disengaged from channel 32 and set aside. 
Thus, disassembly of the panel does not in itself destroy the panel or any 
other parts of the system. 
When the roof is put back, the clamping members must again be temporarily 
spaced out so that the roof panels will be under tension when the wire 
splines have been driven in. 
An assembled roof of this kind is able to support snow loads and positive 
and negative wind pressures. It bulges inward or outward as indicated by 
the dotted lines 11 and 12 in FIG. 1, elastically deflecting the clamp 
member 3, as indicated by the dotted line 37. But when the applied 
pressure drops back to zero, the clamp members stretch the panel flat 
again. When temperature changes occur, the panel may expand relative to 
the frame, and the clamp member 3 will then draw in elastically and 
reversibly as indicated by the dotted line 38, as the panel increases in 
width. The corresponding length increase causes the clamp members 3, to 
slip along the beam 2, under the heads of the nails 4, as permitted by the 
slots 34. The clamp member 302 also moves toward the frame member 23. 
These various deformations take place without causing any relative motion 
of the panel with respect to the seal bead 61, although the web of the 
seal is elastically deformed. Because the clamp members are short, very 
little longitudinal differential slipping takes place inside the channel 
32, so the panel remains firmly gripped by the spline wire 5, while the 
seal remains leak proof. 
The foregoing specification describes a translucent roofing system which 
permits the entry of light while durably preventing the entry of wind and 
rain. It withstands all loads and temperature variations normally 
encountered. It can be systematically assembled or disassembled without 
the use of special tools. All the parts can be fabricated economically 
with known technology. 
Although the invention has been described in terms of a roof, it is clearly 
also useful in the construction of other exterior building surfaces such 
as walls. Therefore, the words "roof" and "roofing system" and "roofing 
means" in this specification and claims are intended to mean any exterior 
surface of a building.