US 3376879 A
Description (OCR text may contain errors)
April 1968 c. F. HUDDLE 3,376,879
PORTABLE SHELTER 29 27 so E- MAIZHQQVL E. E1
1 1 INVENTOR. km E 5 United States Patent This invention relates to a portable shelter which could be classified as tentage.
This application is a division of application Ser. No.
305,483, filed Aug. 29, 1963, now Patent No. 3,215,153, which was a continuation-in-part application of application Ser. No. 286,563, filed June 10, 1963, and now abandoned.
These shelters can be used for temporary or semipermanent type structures that are extremely simple in design and erection, offer fairly low wind resistance, have the ability to absorb wind impact loads, and by arrangement of design proportionment achieve many variations of attractive appearance. While very little variation of aesthetic treatment or flexibility of design can be attained by the use of two triangular arches, these flexibility and aesthetic values are greatly increased when three or more triangular arches are used. An entirely new design concept emerges. When the basic principles of semirigid arch design are applied to the triangular arch fabrication and a membrane is suspended between these triangular arches to form the roof, new attractive structures are possible that can be lightweight, inexpensive, extremely colorful, easy to fabricate, easy and quick to erect, and lend themselves to sectionalizing for transportation.
The object of this invention is to introduce a new concept in tents or portable shelters that by the various configurations possible, these shelters can be fairly low in wind resistance, can be made to withstand wind impact loads due to the semirigidity of the main structural members, and can be entirely different in shape which in turn provides a different interior space that is well suited for many activities.
A further object of this invention is to provide a shelter composed of three or. more simple triangular arches to which a membrane is attached (or supported by a tension system between the arches) and stretched between them to form a roof; side walls or enclosures between the arch members and the. ground or base that can be detached or can serve as an anchoring system for the arch-membrane roof system; and an anchoring system to position the arches and thereby support the roof system.
The triangular arches are inclined outward from each other and can be so designed that the two arch legs have a high slenderness ratio to give the arch a semirigidity or resilience. This resilience enables the structure to withstand higher wind loads with less cross sectional area of arch material. These triangular arches can of course be designed to be practically rigid if it is so desired, and expense is unimportant. The inclination of the arches can vary to effect the architectural treatment desired; however, they usually will be under 60 with the base, as the ideal position of the anchoring systemis 90 with the arch member to which it is attached. Arch legs and/ or arches can vary in their moment of inertia as a method of detuning the resilient system of the entire structure.
Still another object of this invention is to provide a roof with excellent drainage from the peaked design. Such a shape is preferable where high snow loads are common. The roof can be made of a strong fabric, coated fabric, or combination of fabrics having plain or different colors; opaque, translucent or transparent in whole 'or in part. These membrane roofs can have a tension support system to which the membrane can be attached. It can be held in position by stretching the membrane, or a transverse tension system, in the transverse direction to the main roof tension support system. The roof may be contoured for a variety of appearance effects by the transverse tension system; Thus, the roof can be made curved at the roof intersections, or these intersections could be made with almost a straight V effect. This further enables the designer to obtain flexibility in architectural treatment. 'It is impractical to design such roof systems without sufficient sag. To decrease the tension forces, various sag" factors from 5% to 30% or more of the span can produce some dramatic effects.
Still another object of this invention is to enable the designer to obtain a variety of architectural treatments by shaping the end enclosures outward, straight down, or inward between the triangular arch and the base. These enclosures under or within the arch can be omitted in part or in total as desired. They may have openings for ventilation, light, etc., or they may be opaque, translucent or transparent to gain some glamorous effects. They may also be so designed that they act as the arch anchoring system which positions the arches and the roof system.
Still another object of this invention is to provide an anchoring system that is comprised of cables, a side wall system in tension, or rigid or flexible columns set at various angles with the arches and the base. A combination of columns and cables can be used to form trusses," using the ground or base as one of the truss members. Such an arrangement may be preferable where only a slight movement of the arch members can be tolerated under a changing roof or wind load.
'In the overall concept of these structures one can see that the side wind loads must be much less than that of a vertical wall tent of equivalent size, as only a portion of the wall facing the wind will be perpendicular to the wind direction. This enables the wind to spill off most of the surfaces.
Large, unobstructed interior areas can be gained with structures having a multiplicity of arches. Such tents with strong fabrics for roof and side Wall membranes are inexpensive, clean and beautiful in their simplicity of design, and yet can be lightweight, sturdy and dependable shelters.
It is pertinent .to mention that this type structure was disclosed by the drawings and specifications of the parent application Ser. No. 286,563, filed June 10, 1963. Many of the objects cited therein apply to this divisional application for these structures. 3
As pointed out in previous copendin'g applications, the feet of the inclined arches are attached to the base or to eachother in such a manner that they will transmit the arch thrust load. The feet or the ends of the arches may be located adjacent to each other in such a manner that the horizontal thrust component of one arch opposes the horizontal thrust of the other. The feet of the arches, of course, can be separated. In such a case the horizontal thrust components may oppose each other indirectly through a structural member between them or through a support or base.
It is al-so practicable in some cases to use intermediate supports for the roof system to obtain higher headroom, to give added support to the roof system, or for purely aesthetic reasons.
,The details as well as other objects and advantages .of this invention are further described with reference to the accompanying drawings. FIG. 1 and FIG. 3 show the skeleton framework of arch legs 12 connected at the apex 24, and interconnecting ridge members 13 joined by a connection 16 between the apexes of the arches. The arch legs 12 are attached to a base 15, and the arches and roof ridge members are held in position by the tension member 1 4 which is attached to the support by a stake 40 or other anchoring means.
FIG. 2 is a perspective view of a shelter having three triangular arches. The membrane 17, attached to the arches 12, rests on the ridge member 13. The arches are attached to the base point 15 which is secured to the support by a stake 23 (FIG. 9) or other means. The tension member 14 and the stake 40 comprise the anchoring system. The membrane 17 can be supported by tension members 18 that extend between the arches, and can be preloaded or shaped by the inverted tension members 19, the members 18 running along lines parallel to the ridge members 13 and the members 19 running along lines perpendicular to the tension members 18. Valley lines 42 extend between the upper central connecting point 16 and the base points 15. The members 19 are connected between the ridge members 13 and the arch legs 12. The inverted tension members 19 or the tension support members 18 can be attached to the membrane 17 to hold it in place. In other words, the members 19 may act just the opposite of the members 18, the latter providing support for the membrane 17 and the former holding the membrane and/or the members 18 down, preventing ballooning."
FIG. 4 is a plan view of a four sided shelter made with four triangular arches.
FIG. 5 and FIG. 6 illustrate the assembly of a shelter with five triangular arches 33 as the compression members or the structural skeleton. The membrane 39 has ridge lines 38 and an additional support member 34 in the center of the star shaped shelter. The tension members 35 are attached to the anchor 36, and the arches again rest on the ground directly or through a base plate 37.
FIG. 7 is a side elevation of the same shelter shown in FIG. 4 where the arches 2 7 have a membrane 29 stretched or suspended between them. A ridge line 30 connects the apexes of the four arches. The lower ends of the arches are located on the base by a base plate 31 which is attached to the base or ground. The anchor member 28 is attached to the arch 27 and to the base by a stake 32 or other means.
'In FIG. 8, a single arch 12 is shown with a rigid connection 24 at the apex of the legs or a hinged connection 25 between the legs at the apex. The arch rounded ends and locating pins 22 are at the feet of the arch.
In FIG. 9 and FIG. 10 one method is shown by which the arches 12 are located on a base plate 15 which is anchored to the ground or base by a stake 23 or other suitable means. In this case the arch end is rounded so that it can pivot, but the end is fitted with a pin 22 which is inserted in the hole in the angle 21 which is fixed to the base 15 by welding or other means. It is realized that for small shelters the pins 22 could be made longer and forced in the ground to act as an anchor stage 23. In the latter case the plate 15 would not be required. When some tents such as these, or if they are very large structures, are erected on a soft base; it may also be desirable to place a cable or other tension member 41 (FIG. 1) between the arch feet or arch ends to keep them from spreading. In some cases it may be desired to use a rigid connection between the adjacent arch ends at the base plate 23 to fix the relationship between the arch ends in such a manner that the horizontal thrust line between the arch ends will not change, and, thus, these forces from the adjacent arches can be made to oppose each other.
In FIG. 11, one method of attaching the anchor cable or column bar 26, welded or otherwise fastened to the apex connector 24, is shown. It is desired to point out that this anchor member or members need not be fastened to the arch at this point, as the arches can be held in position by attaching the anchor system to various points of the arch. Or, an end wall system (FIG. 2) can be made strong enough to locate the arch in relation to the base.
This latter method is, of course, better accomplished if the end wall system extends outward from a line between the arch feet. It would slope upward toward the apex similar to the anchor member 14 shown in FIG. 2 and would be attached to the base.
FIGURE 12 is a more detailed illustration of FIG- URE 2.
From the three-, fourand five-arch shelters illustrated, one can see that additional triangular arches can be easily added to form many different shelter shapes. Some of the arches in the same structure may be higher than others by extending the arch legs or erecting them to a lesser acute angle with the base. There are many conceivable shelter shapes that can be made with various combinations of triangular arches or combinations of triangular and curved arches. The curved arch structures were described in a copending divisional application mailed Oct. 14, 1965, in which both curved and triangular arch shelters were disclosed.
1. A portable shelter comprising a plurality of more than two triangular arches, said arches being inclined at an acute angle from a common support and tilted outward from the center of said shelter, a flexible membrane attached to said arches and stretched between them to form a roof structure, and an anchoring system between said arches and said support for retaining said flexible membrane in tension.
2. The shelter described in claim 1 wherein said arches are resilient arches movable in response to variable wind forces.
6. The shelter described in claim 1 wherein said membrane is supported by a tension system between said arches.
4. The shelter described in claim 3 wherein the flexible membrane and the supporting tension system are held in position and preloaded by an inverted tension system.
5. The shelter described in claim 1 wherein the flexible membrane is a fabric type, reinforced with webbing.
6. The shelter described in claim 1 wherein the anchoring system that positions the arches and the roof system consists of end wall enclosure panels.
7. The shelter described in claim 1 wherein the roof tension system includes a center support member.
-8. The shelter described in claim 1 wherein said arches have pivotal ends.
9. The shelter described in claim 1 wherein said arch legs are hinged at their common apex.
10. The shelter described in claim 1 wherein the arch members are sectionalized.
11. The shelter described in claim 1 wherein the apexes of the arches are connected by a rigid tension member.
References Cited UNITED STATES PATENTS D. 199,733 12/ 1964 Hastings -1 2,797,696 7/1957 Fritsche 135-l 2,818,078 12/1957 White 1351 3,016,115 1/1962 Harrison et a1. 135-1 465,084 12/1891 Kaufert 135-3 2,236,677 4/ 1941 Eddy 135--3 3,010,463 11/1'961 Wade 135--3 3,043,320 7/1962 Moss 135-3 FOREIGN PATENTS 64,846 12/ 1949 Netherlands. 86,500 1 1/ 1958 Denmark. 875,945 7/ 1942 France. 1,121,851 5/1956 France.
REINALDO P. MACHA'DO, Primary Examiner.
HARRISON R. MOSELEY, Examiner.
A. I. BREIER, Assistant Examiner.