Patent Publication Number: US-9890555-B1

Title: Portable shelter

Description:
STATEMENT OF GOVERNMENT INTEREST 
     The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties. 
    
    
     BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     The present invention relates to portable shelters. More particularly, the present invention relates to light-weight shelters with reversible thermal panels for interior heating and cooling. 
     (2) Description of the Prior Art 
     There is always a need for light-weight, easy to deploy structures geared toward the comfort and survivability of campers, military personnel, and even refugees and other indigenous people in poor countries. Some areas of the world can experience nearly 300 sunny days per year, maximum temperatures of near 95° F. to lows around 20° F. and constant winds ranging from 5 miles per hour (MPH) to 14 MPH, all in a relatively arid climate yielding wind chills near zero degrees Fahrenheit. Rainfall averages in these areas are often less than 12 inches per year. 
     Conventional tents utilized in cold weather tend to form warm vapor on inside tent surfaces, making conditions inside unpleasant. The water that condenses from the vapor, if retrievable, would be a benefit in arid areas. For example, on a typical evening in such conditions, about one cup of water from a person&#39;s exhaled air can condense on a tent wall surface and begin to drip on occupants, which can be a serious problem. In a tent built for two this could result in as much as sixteen ounces of water being dripped onto occupants and gear making the environment cold, wet, and uncomfortable. These tents also typically have poor thermal control features. 
     Thus, a need has been recognized for a structure useable as a tent that is easily deployable and storable, and that also provides thermal comfort to those within the structure in extremes of hot and cold. Additionally, the structure needs to prevent water condensation from dripping onto occupants and other contents within such a structure. Further, the structure should enable recovery of water condensate within the structure. 
     SUMMARY OF THE INVENTION 
     It is therefore a general purpose and primary object of the present invention to provide a structure, useable as a tent, having a first cover and structural elements disposed therein to permit the first cover to lay flat or stand erect. The first cover has at least two layers. One such layer reflects ambient heat and another layer absorbs ambient heat. Similarly constructed removable panels can be attached to standoffs incorporated in the structure. 
     As a result, the structure can stand erect with either one of the layers directed outwards and the other inwards. This permits a user to readily deploy the structure in either a cooling or heating mode, or fold it for easy storage. The structure defines an enclosed living space which is cooled or heated with respect to the ambient environment depending on which layer is outwardly disposed. Additional ambient cooling or heating can be provided by appropriately attaching the removable panels. The standoffs separate the removable panels from the first cover and provide an air space between the cover and panels for increased efficiency in cooling and heating. 
     The structure can have a detachable base with a cavity fillable with fluid such as air or water, to give the structure added stability, particularly in high winds, and provide thermal inertia to insulate the enclosed space from the ground. The structure can also have a water collector that uses the lotus effect to collect condensate on the top of the enclosed space to prevent the condensate from dripping on an occupant, and to permit recapture and reuse of the water, a particular advantage in dry environments. 
     In one embodiment, a structure includes a cover having a pair of sides. A first layer disposed on one side is fabricated of a material selected to reflect ambient heat from the first layer. A second layer disposed on an opposite side is fabricated of a material selected to absorb ambient heat. A plurality of structural members are disposed in the cover and permit the cover selectably to lay flat or to stand erect to define an interior space within the cover. The structural members are further disposed to selectably permit either the first layer or the second layer to be disposed in the interior space. 
     A plurality of panels is removably attachable to either side of the cover. Each of the panels has one side fabricated of the first layer and an opposite side fabricated of the second layer. The structure further includes another structural member disposed within each of the panels effective to permit the panels selectably to fully extend or to fold flat and compact. 
     A plurality of standoffs are attached about the cover, such that the panels attach to the standoffs. The standoffs are attached about the cover adjacent the structural members. The standoffs have a thickness to provide an air gap between the cover and the panels attached to the standoffs. The standoffs can have varying thicknesses to provide varying air gaps and the standoffs can be removably attached about the cover. The structure can also include a base removably connected to the cover, with the base extending beyond a perimeter of the cover to provide anchorage for said structure. 
     In one embodiment, a portable pop-up shelter includes a cover having an ambient heat reflective layer on one side and an ambient heat absorptive layer on an opposite side. A plurality of spring loops is disposed in the cover and arranged to permit the cover to be selectably laid flat or stood erect to define an interior space of the shelter. The spring loops are further arranged to selectably permit either of the reflective layer or the absorptive layer to be disposed within the interior space. 
     A plurality of standoffs are attached to the cover, with a number of the standoffs being attached to and extending away from the reflective layer and a remainder of the standoffs being attached to and extending away from the absorptive layer. A plurality of panels are removably attachable to the standoffs on either side of the cover. Each panel has an ambient heat reflective layer on one side and an ambient heat absorptive layer on an opposite side. 
     The shelter further includes a spring loop disposed within each of the panels, so as to permit the panels to fully extend or to fold flat and compact. The standoffs have a thickness so as to provide an air gap between the cover and the panels attached to the standoffs. The standoffs can be removably attached about the cover adjacent the spring loops. The standoffs can have varying thicknesses to provide varying air gaps. The shelter can include a base removably connected to the cover. The base can extend beyond a perimeter of the cover to provide anchorage for the shelter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of the invention and many of the attendant advantages thereto will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein like references numerals and symbols designate identical or corresponding parts throughout the several views and wherein: 
         FIG. 1  is an elevation view of one embodiment of the invention; 
         FIG. 2  is an elevation view of the invention showing the installation of removable panels on the structure; and 
         FIG. 3  is a detailed sectional view taken along line  3 - 3  of  FIG. 2 . 
     
    
    
     DESCRIPTION OF THE INVENTION 
     Referring now to  FIG. 1 , there is shown a structure  10  having a cover  12 , preferably in the form of a fabric shell, into which is sewn, in any conventional manner about cover  12 &#39;s periphery, spring loops  14 . Cover  12  mounts on an optional base  16 , which may be detachable. Standoff blocks  18  are attached to structure  10 . More particularly, blocks  18  are attached to cover  12  at points along spring loops  14 . 
     Spring loops  14  make structure  10  a pop-up structure such that, by use of the outward force of spring loops  14 , and by pushing or pulling structure  10  in the vicinity of handle  20 , one can cause structure  10  to flatten or to deploy upright as shown in  FIG. 1 . More importantly structure  10  is reversible and can be deployed with either side of cover  12  outwardly facing, or either side inwardly facing. For full reversibility, blocks  18  are attached on both sides of cover  12 , such that blocks  18  are both outwardly facing and inwardly facing. 
     The combination of cover  12  and spring loops  14  permit structure  10  to be folded and laid flat such that spring loops  14  can be disposed one on top of each other, and then the loops twisted, perhaps several times, in figure-eight patterns to fold structure  10  into a compact size suitable for easy storage in a relatively small space. Such pop-up structures are usable as quick-deployable tents, and structure  10  is illustrated as a tent. Sealable door flap  22  permits entry and exit. 
     Referring now also to  FIG. 2 , removable panels  24  are shown disposed over cover  12 . As with cover  12 , removable panels  24  are preferably in the form of a fabric shell, into which are sewn, in any conventional manner about the periphery of removable panels  24 , additional spring loops  14 . Accordingly, removable panels  24  also can fold into a compact size suitable for easy storage in a relatively small space. Sealable door covering  26  permits access to door flap  22 . For ease of access, door covering  26  may be removable. 
     Referring now to  FIG. 3 , there is shown a cross-sectional view of removable panels  24  attached to cover  12  of structure  10 , taken at line  3 - 3  of  FIG. 2 . Cover  12  and removable panels  24  are each seen to have a fabric base  28  on which are layers  30  and  32 , one of which is thermally reflective, and one of which is thermally absorbent. Note that layers  30  and  32  can also be in direct contact with each other, eliminating the need for fabric base  28 . 
     Standoffs  18  are affixed to opposite sides of cover  12 . Connections  34  are affixed to opposite sides of removable covering  24 . Connections  34  mate with standoffs  18  when removable panels  24  are placed about structure  10 . Standoffs  18  provide air space  36  between cover  12  and removable covering  24 . As can be seen in  FIG. 3 , standoffs  18  can be of differing thicknesses on opposite sides of cover  12  to provide a larger or smaller air space  36 . Additionally, standoffs  18  can be removably attached to cover  12 , thus providing the opportunity to attach standoffs  18  of varying thicknesses for differing environmental conditions. 
     In practice, in a hot environment, one deploys structure  10  with the thermally reflective (i.e., heat reflecting) side of cover  12  outwardly disposed to reject solar heat and thus keep the inside of structure  10  cooler than would be possible without the reflective surface. Removable panels  24  can be attached to the outside of structure  10 , as shown in  FIGS. 2 and 3 , also with the thermally reflective (i.e., heat reflecting) side of removable panels  24  outwardly disposed. Removable panels  24  serve to further reduce the thermal load on the tent by both reflection and shading. Additionally, air gap  36  induces air convection between cover  12  and removable panels  24  to further reduce the thermal load. 
     Conversely, if structure  10  is in a cold environment, one would deploy structure  10  with the thermally absorbent (i.e., solar absorptive) side of cover  12  outward to take in heat from the environment. Removable panels  24  can further be deployed within structure  10  with the thermally absorbent side of removable panes  24  also outward. In this manner, the thermally absorbent side of cover  12  absorbs ambient heat and in turn heats through to the opposite side of cover  12 . 
     Air gap  36  conveys heat to thermally absorbent side of removable panels  24 , which heats through to the opposite side of removable panels  24 , thus warming the inside of structure  10 . Air gap  36  can be minimized by minimizing the thickness of standoffs  18 . In so doing, it is possible to have direct heat transfer between cover  12  and removable panels  24 . 
     As can be seen in  FIG. 3 , connections  34  not only provide for removable panels  24  to be removable, but also removable panels  24  are reversible. The reversible nature of structure  10  and removable panels  24 , as well as the use of removable panels  24  both external and internal to structure  10 , allow for the structure  10  to be configurable for all thermal environments. For example, conditions on a cool spring day may warrant structure  10  be in a thermally absorbent configuration, i.e., having a thermally absorbent layer facing outward. However, one or more of removable panels  24  attached to the outside of structure  10  may have a thermally reflective layer facing outward to reflect away a portion of the solar gain. 
     The material constituting cover  12  may be one of a number of fabric textile materials that can be metalized with a highly ultraviolet/infrared (UV/IR) reflective coating on one side and a black matte metallic coating on the other. The black matte coating does not necessarily have to be metallic but a metallic coating is preferable for enhanced thermal transmission of absorbed radiation to the interior of structure  10  when in the heating configuration indicated above. 
     While many different composite fabric choices may be employed, a particularly advantageous choice for simplicity and durability is a light-weight Mylar/Kevlar/Mylar composite metal coated on one side with highly reflective aluminum or silver oxide, and coated on the other side with a black metal oxide such as Black-Chrome for solar radiation absorption. 
     As is known in the art, cover  12  can include a band of moisture absorbing fabric (not shown) running the circumference of cover  12 . Warm, moist exhaled air from occupants encountering a cooler interior wall can condense. The moisture absorbing fabric help keep moisture from pooling on the floor and wetting occupants or contents. 
     As also known in the art, base  16  can enclose a chamber (not shown) that one can fill with a fluid such as water, air, or the like to both thermally insulate the interior of structure  10  and provide a softer floor inside for sitting. If base  16  is filled with water and securely attached to cover  12 , structure  10  will not require any external anchors to hold structure  10  in place during high winds. Additionally, a water filled base  16  will help moderate the temperature inside via thermal mass. 
     By extending base  16  beyond the periphery of cover  12 , as shown in  FIGS. 1 and 2 , base  16  can allow for external sand-bagging should such be desired by the user. Alternately, a separate fabric flap (not shown) can be incorporated into structure  10  for sand bagging purposes. Additionally, structure  10  can incorporate a moisture collection system. As is known to those of skill in the art, such systems can collect and recycle as much as 16 ounces of fresh water per day. 
     What has thus been described is a structure  10 , which can be used as a portable shelter or tent. Structure  10  includes cover  12  and structural elements (spring loops  14 ) disposed therein to permit cover  12  to lay flat or stand erect. Cover  12  has at least two layers ( 30 ,  32 ), with one layer capable of reflecting ambient heat and another layer capable of absorbing ambient heat. Similarly constructed removable panels  24  can be attached to standoffs  18  incorporated in structure  10 . 
     Structure  10  is reversible, so that structure  10  can either reject or absorb ambient heat, making structure  10  cooler in hot environments and warmer in cool environments. Standoffs  18  are provided on each side of cover  12 , such that removable panels  24  can be attached to the interior or exterior of structure  10  to provide additional cooling or warming for occupants within structure  10 . Connections  34  for attaching removable panels  24  to standoffs  18  are provided on both sides of removable panels  24 , such that either side of removable panel  24  can face towards cover  12 . Additionally, standoffs  18  can be removably attached to cover  12  and various standoffs  18  can have varying thicknesses. Accordingly, the size of air gap  36  formed between cover  12  and removable panels  24  can be varied. 
     Obviously many modifications and variations of the present invention may become apparent in light of the above teachings. For example, the materials forming cover  12  and removable panels  24  can be any number of materials known to those of skill in the art to reflect or absorb ambient heat. Removable panels  24  need not be constructed of the same materials as cover  12  and differing removable panels  24  may be constructed of differing material. 
     Standoffs  18  can be constructed of varying material, such as neoprene or other plastics, provided they are constructed with sufficient stiffness to maintain air gap  36  between cover  12  and removable panels  24 , as well as being able to withstand expected environmental conditions over extended time periods. Standoffs  18  can be attached to cover  12  in any manner known to those in the art, including being sewn into cover  12 . For removable standoffs  18 , mating Velcro strips can be attached to cover  12  and standoffs  18 . 
     It will be understood that many additional changes in details, materials, steps, and arrangements of parts which have been described herein and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims.