US 3057368 A
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Description (OCR text may contain errors)
N. R. sEAMAN Oct. 9,
Diallo FIG. A2
ATTORNEYS N. R. SEAMAN COMPOSITE AIR DOME STRUCTURE Oct. 9, 1962 2 Sheets-Sheet 2 Filed May 5, 1960 FIG. 8
NORMAN EAMAN BY ATTORNEYS A3,057,368 Patented Oct. 9, 1962 hee 3,657,368 CMPSTE Am DOME STRUCTURE Norman R. Seaman, RD. 1, Holmesvlle, Ohio Filed May 3, 1960, Ser. No. 26,615 8 Claims. (Cl. 13S-1) The invention relates generally to inatable bag-like structures which are continuously maintained in a blownup condition on a supporting surface by a blower or the like. More particularly, the invention relates to an inated outer bag or dome wholly enclosing a frame-supported, air-sealed structure.
Inflated bag-like structures are usually made of plastic film material and may be called air domes. They have the advantages of being made and transported economically, and of providing a shelter which is quickly and easily erected or collapsed and which greatly `reduces the design loads for wind resistance because of their spherical or dome shape. However, these air domes have a number of disadvantages, including the following:
rl'he plastic film material is subject to rupture from a variety of causes resulting in accidental collapse of the structure. Special air-lock type doors are required for ingress and egress to prevent loss of air. A constantly running blower of substantial capacity is required to compensate for air losses through the doors and ground seals, and this causes an undesirable draft condition for the occupants. These air losses and the lack of thermal insulation make it difficult and expensive to heat and maintain the temperature of the air within the dome.
Other tent-like structures having a framework supporting film material have been proposed, and these do not require air inflation `but have a number of other disadvantages. For example, a geodesic structure such as disclosed in U.S. Patent No. 2,682,235 provides a lightweight framework having relatively low design loads which may be used to support the film or skin, but it must be designed for the most severe uneven loadings due to wind and snow conditions. Moreover, scaffolding or structural rigging is required to erect the framework. Also, because the skin must be designed for point loading where it is attached to the framework, the patterning and construction of the skin is a difficult and relatively expensive operation.
Another disadvantage of using a geodesic framework to support the skin is that it is necessary to support the skin from the inside of the framework to make it waterproof because of the difficulty of lifting the heavy whole skin over the outside of the framework and the danger of wind damage during the erection. Thermally insulating such a skin is a complicated and expensive task, usually requiring two spaced-apart waterproof skins to provide a dead air space.
It is a general object of the present invention to provide a novel and improved composite air dome structure which overcomes the disadvantages of both air domes and framesupported skins, while retaining the principal advantages of both.
More specifically, it is an object to provide a novel composite dome structure having an outer dome which is quickly and easily erected by inflation, which will efliciently resist the severest wind and snow loads, and which provides an overhead support for erecting a separate structure enclosed within the dome, regardless of weather conditions.
Another object is to provide a novel composite dome structure having an inner framework-supported skin and an outer inflated skin normally supported solely by air pressure between the skins, so that air at atmospheric pressure may be maintained within the inner skin, and doorways extending through the space between the skins do not require air locks.
A further object is to provide a novel composite dome structure having an inner chamber thermally insulated by an air blanket from the outer atmosphere while permitting the transmission of a substantial amount of daylight into the inner chamber.
Referring to the drawings forming part hereof:
lFIG. l is a somewhat schematic vertical sectional view on line 1-1 of FIG. 2 of the novel composite air dome structure in inflated condition, showing the manner of hoisting the inner framework from the central part of the outer dome.
FIG. 2 is a plan view, with parts of the outer and inner skins broken away.
FIG. 3 is an enlarged fragmentary view on line 3-3 of FIG. 2 showing the base of the inner framework with the inner skin supported on the inside of the framework.
FIG. 4 is a similar View of a modified construction, showing the inner skin supported on the outside of the framework.
FIG. 5 is an enlarged fragmentary View on line 5-5 of FIG. 2 of the central portion of the outer dome, showing a lifting ring secured to its inner surface.
FIG. 6 is an enlarged fragmentary View taken within the circle on FlG. 1, showing the manner of supporting the skin on the inside of the inner framework.
tFlG. 7 is a schematic vertical sectional view through a doorway leading into the inner chamber.
FIG. 8 is a view similar to FIG. 1, showing a modified form of inner framework supporting an outside skin.
The outer skin or film 10 may be made of any exible transparent or translucent plastic material such as polyethylene or polyvinyl chloride, and may comprise a plurality of spherical sections 11 joined together by fluidtight seams along the gore lines 12. Preferably, the seams are electronically Welded. As indicated in FIG. 1, the skin 10 has an inlet port 13 to which a blower 14 is connected for supplying and maintaining air under pressure within the outer skin which is designed to assume a hemispherical or dome shape when inated and supported on the ground or other support.
The inner framework may be a geodesic structure, indicated generally at 15, such as shown and described in U.S. Patent No. 2,682,235, comprising a plurality of struts 16 forming substantially equilateral triangles arranged to form a partial dome in spaced relation to the outer skin and connected at its base to the base of the outer skin. The struts are connected to each other by suitable couplings 17 described in said patent, and the framework is provided with a circular ring 18 at its base.
Referring to FIG. 3, the base ring 18 of the framework may be supported at suitable circumferential intervals (e.g. l0 feet) by steel structural members indicated at 20, each resting on a pad or foundation 21. The outer skin 1i) is attached to the base ring between struts 16 by loops 22 of the skin material. Overlying the loops 22 is an outer circumferential flap or skirt 23 of the skin material which extends radially inward under the base ring around its entire circumference except for doors. Where'the skirt is interrupted to pass the structural supports 20, ground flaps 24 are provided to make an air seal around the supports. All of the seams in the loops 22, skirt 23 and flaps 24 are electronically welded or otherwise sealed to make them airtight.
As shown in FIG. 3, the skirt 23 may have its radially inner portion overlap and be laced by a iiap 25 to an inner skin 26, which may be hung from the inside of the geodesic framework at some or all of the couplings 17 connecting the struts 16. The skin 26 may be of the same material as the outer skin or it may be a different material having somewhat different characteristics such as a high thermal insulation factor.
As seen in FIG. 6, each coupling 17 has an eye bolt 27 extending from its inner end, and the skin 26 may be supported therefrom by a chain 28 which is attached to an eye bolt 29 at the center of a metal doublewall disk 30 clamped around its periphery over a circular hem in the skin enclosing a cord or rope 31 to make an airtight seal. The inner skin 26 divides the hemispherical chamber dened by the outer skin into two chambers, the upper chamber being substantially crescent-shaped in cross Section, as indicated in FIG. 1, and containing the air maintained under pressure by the blower 14. The lower chamber contains atmospheric air when the strueture is completed.
When the inner skin is supported on the top or outside of the geodesic framework, as shown in FIG. 4, the inner and outer skins 126 and 110 may be connected to form a seal above the loops 122 surrounding the base ring 118. The outer edge of skin 126 may be laced to a flap 132 welded to the inside of skin 110, and a sealing ap 133 overlies the laced joint and is welded to both skins. In
this case the outer skirt 123 may extend under the base ring during erection as indicated in full lines, and may be subsequently extended outwardly to form a weather seal ground flap, as indicated in dash lines.
As shown in phantom lines in FIG. 4, in order to provide working space between the inner structure and outer skin, the outer skin 110 may have a separate anchored base ring 118 spaced outwardly of the base ring 118. A flap 133' would then be provided to connect the outer skin 110 to the inner skin 126, which lwould be attached to the inner ring 118 by loops 122'.
A-s shown in FIG. 7, it is not necessary to construct special air-lock doors to allow ingress to and egress from the lower chamber. The door frames 35 are merely formed where desired in the base of the framework 15, and the inner and outer skins and 26 are sealed together and supported by the top 36 of the door frame, either below or above the same.
In erecting the novel composite air dome, the outer skin 10 is first erected at the desired location merely by introducing air therein from the blower 14. The skirt 23 extends radially inward around the outer periphery of the skin to provide a fairly good air seal with the ground or other support. As indicated in FIGS. 1 and 5, the upper portion of the outer skin is preferably provided on its inner surface with a hoisting or lifting ring 38 carried in a loop-shaped circular flap 39 welded to the skin. Hoisting cables 40 are hung from the ring 38 at intervals.
After the outer skin is fully inflated, the geodesic framework is erected within the outer skin, and consequently the framework can be erected regardless of weather conditions due to the protection afforded by the outer skin. The top portion of the framework is erected on the ground irst and then raised progressively by the cables 40 as the lower portions of the framework are added. When the framework is completed, the base ring is attached to the outer skin by the loops 22 or 122.
Next, the inner skin 26 or 126 is hung from or placed over the framework and joined at its outer periphery to the outer skin in the manner previously described. Due to the protection from the elements provided by the outer skin, the inner skin may be applied over the framework in sections for ease in handling, and the sections seamed together in place. After the inner and outer skins are joined together, the air in the lower chamber is allowed to become atmospheric and the air pressure maintained in the upper chamber.
As shown in FIG. 8, the inner framework may be of conventional building construction comprising studs 250 and rafters 251 carrying the inner skin 226 on the framework in spaced relation to the outer skin 210, and the two skins being sealed together between the framework and the outer skin. The inner skin may be supported on the inside of the framework, or on the outside thereof as shown. Where doors are located, door frames are preferably provided connecting the framework to the base 4 ring and supporting the joined rskins above the doorway, similar to the construction shown in FIG. 7.
In all embodiments, after the inner skin is supported on the inner framework and sealed to the outer skin, the blower is required only to maintain the desired air pressure in the upper chamber, which is completely sealed, so that a blower of relatively small capacity may be used. It has been found in actual practice that air pressures of 71/2 to lll/1 pounds per square foot will maintain the outer skin in place against the severest snow loads and winds of 50 to 75 miles per hour. Even higher velocity winds will merely slightly depress or distort the skin without harm. However, should the outer skin become ruptured for any reason, it will be prevented from total collapse by the inner framework.
Since the inner framework is at all normal times protected by the outer skin, the framework can be designed for uniform reduced loading conditions, resulting in a substantial savings in material and handling costs.
The upper chamber of air thermally insulates the lower and inner chamber, so that maintaining a desired temperature within the inner chamber is greatly facilitated, regardless of outside weather conditions. If desired, a layer of insulating material, such as polyurethane foam, can be supported on the inner framework to further insulate the inner chamber.
The novel composite air dome structure is adapted to be used to protect and enclose areas for various purposes. For example, it is adapted to cover Water reservoirs, and can be erected from oats supported upon the surface of the water. Moreover, it can be erected under almost any climatic condition, because the outer skin is erected merely by inilation and provides a protective housing for the erection of the inner framework and skin.
By using transparent or translucent material in both the inner and outer skins, an optimum of natural light can be transmitted to the inner chamber, thereby reducing the amount of articial lighting required.
What is claimed is:
l. Composite air dome structure comprising an outer air-supported dome-shaped skin, a base ring attached to the base portion of said skin, a geodesic framework carried on said ring within said skin, and an inner ilexible skin having a continuous air seal connection with said outer skin base portion and supported on the outer surflce of said framework in spaced relation to said outer s. in.
2. Composite air dome structure comprising an outer air-supported dorne-shaped skin, a base ring attached to the base portion of said skin, a geodesic framework carried on said ring within said skin, and an inner exible skin having a continuous air seal connection with said outer skin base portion and supported on the inner surfce of said framework in spaced relation to said outer s.1n.
3. Composite air dome structure comprising an outer air-supported dome-shaped skin, means anchoring the base portion of said skin to a support, a geodesic framework carried on said means within said skin, and an inner flexible skin having a continuous air seal connection with said outer skin base portion and supported on the outer surface of said framework in spaced relation to said outer skin.
4. Composite air vdome structure comprising an outer air-supported dome-shaped skin, means anchoring the base portion of said skin to a support, a geodesic framework carried on said means within said skin, and an inner exible skin supported on the inner surface of said framework in spaced relation to said outer skin and forming a sealed air chamber between said skins.
5. Composite air dome structure comprising an outer air-supported -domeashaped skin, a base ring attached to the base portion of said skin, a geodesic framework carried on said ring within said skin, an inner flexible skin having a continuous air seal connection with said outer skin base portion and supported by said framework in spaced lrelation to said outer skin, and an air inlet in said outer skin for introducing air under pressure between said skins.
6. Composite air dome structure comprising an outer air-supported dome-shaped skin, means anchoring the base portion of said skin to a support, a geodesic framework carried on said means within said skin, an inner flexible skin having a continuous air seal connection with said outer skin base portion and supported by said framework in spaced relation to said outer skin, and an air inlet in said outer skin for introducing air under pressure between said skins.
7. Composite air dome structure comprising an outer air-supported dome-shaped skin, means anchoring the base portion of said outer skin to a support, a circumferential ap extending radially inward of the base portion of said outer skin, a framework within the outer skin in spaced relation thereto, and an inner exible skin supported on said framework, the outer periphery of said inner skin having a sealed connection with said flap.
8. Composite air dome structure comprising an outer air-supported dome-shaped skin, a framework within the outer skin in spaced relation thereto and having a base, means anchoring the outer skin to said base, a circumferential flap on said outer skin extending radially inward of said base, and an inner eXible skin supported on said framework and having its outer periphery sealed to said ap to form a sealed air chamber between said inner and outer skins.
References Cited in the le of this patent UNITED STATES PATENTS 2,411,316 Capita Nov. 19, 1946 2,819,724 Barker Ian. 14, 1958 2,914,074 Fuller Nov. 24, 1959 2,934,075 Richardson et al Apr. 16, 1960