Patent Publication Number: US-8112943-B2

Title: Convertible hard side shelter

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. Ser. No. 10/957,473, filed on Oct. 4, 2004, now U.S. Pat. No. 7,874,107 the entirety of which is hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention pertains to portable shelters, and more particularly to hard side shelters that convert into different sizes for transportation and use. 
     2. Description of the Related Art 
     It is a well known practice to ship goods in International Standards Organization (ISO) containers. Such containers are very large, having nominal exterior dimensions of 19 feet 10½ inches long, eight feet wide, and eight feet high. The containers have fixed floors, roofs, and ends. Access to the container interior is through folding doors on both sides. The doors are locked closed by locking bars that engage tabs in the container floor and roof. The containers include an end bar and rails under the floor that are part of known pallet handling systems. 
     In theory, ISO containers could be used as hard side shelters for persons and equipment. However, despite their large size, they nevertheless are too small for some shelter purposes. For example, there is a need for shelters that are suitable for repairing large motor vehicle tires in the field. As is known, maintaining the tires of motor vehicles is mandatory for successful operation of the vehicles. A particularly difficult problem associated with tire maintenance concerns military trucks. Those trucks often operate off-road, in rough terrain, and far from repair facilities. A tire failure could jeopardize not only the truck crew in hostile areas, but even the success of the mission of which the truck is a part. 
     Repairing military truck tires is a difficult task. The tires and their rims and wheels are very heavy, so they require mechanical assistance to handle them. Failures associated with heavy truck tires are varied and severe, so a wide variety of large and heavy repair equipment has to be available. Finally, it is vital that the repair equipment either be located close to where the tire damage occurs, or be able to quickly reach the location of the damaged truck. That means that the repair equipment must be able to travel with the trucks to remote and rugged places. Because of the size of the tire repair equipment and the working room required around them, conventional ISO containers are not suitable as tire repair workshops. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, a hard side shelter is provided that converts between a transport mode and a deployed mode. This is accomplished by apparatus that includes a center section, and two side sections that selectively fold into and out of the center section. 
     The center section is preferably constructed with an envelope that is the size and shape of a conventional International Standards Organization (ISO) cargo container. When in the transport mode, the side sections fold into the center section such that the entire hard side shelter has the envelope of an ISO container. When in the transport mode, the convertible hard side shelter can be stacked, handled, and transported in the same way as ISO containers. When in the deployed mode, the side sections unfold from the sides of the center section to greatly increase the interior space available for personnel and equipment. 
     The center section is comprised of a sturdy frame having horizontal beams and vertical corner posts. The corner posts define vertical side planes and vertical end planes of the center section. The center section has a rigid roof and a rigid floor. At least one end of the center section has an opening and an end door. The second center section end may also have an opening and an end door, or the second end may be permanently closed. If the second end is permanently closed, the center section may include an end bar on the closed end and floor channels that enable the convertible hard side shelter to be handled by a conventional pallet handling system. 
     The center section end door may be a single end door or a double end door which can be vertical or horizontal double doors. The single end door is composed of a top door hinged to the frame near the roof and a bottom door hinged to the frame near the floor. The top and bottom doors pivot about respective horizontal axes. When the single end door is open, the top and bottom doors are generally horizontal and parallel to the center section roof and floor, respectively. When the single end door is closed, the top and bottom doors are vertical and lie in the associated center section end plane. The double end door is composed of the top and bottom doors hinged near the roof and floor, respectively, plus a pair of outer doors that are hinged to associated corner posts for pivoting about respective vertical axes. When the double end door is open, the top and bottom doors are horizontal and generally parallel to the center section roof and floor, respectively, and the outer doors are generally parallel to the side section side planes. When the double end door is closed, the top and bottom doors are vertical and lie generally in the associated center section end plane, and the two outer doors are also generally in the center section end plane and lie adjacent and outside of the top and bottom doors. 
     Each side section is comprised of a rigid floor, and a number of relatively turnable panels. In the preferred embodiment, the side section panels include a pair of larger end panels, to accommodate for the same width of the fold down rigid floor, a pair of smaller middle panels, and a door assembly. The side section floor is rotatably connected to the center section. Each end panel is turnably mounted along one edge thereof to a center section corner post. A second edge of each end panel is turnably mounted to a first edge of a middle panel. Second edges of the middle panels are turnably mounted to opposite edges of the door assembly. According to one aspect of the invention, the door assembly is comprised of first and second door frames. The first door frame contains one or more side doors that swing about respective vertical axes. The second door frame has a filler panel. The two door frames are attachable to and detachable from each other. Each of the end and middle panels and the door assembly has at least one locking door. 
     When the convertible hard side shelter is in the deployed mode, the side sections are outside of vertical side planes of the center section. Each side section floor is rotated to be generally coplanar with the center section floor. Each end panel is parallel to the center section end planes. The middle panels, as well as the door assembly, are perpendicular to the end panels. The locking bars engage the side section floors to lock the side sections rigidly to the center section. A cover extends from the center section roof to the top edges of the end and middle panels and the door assembly. Thus, each side section is a space bounded by the side section floor, two end panels, two middle panels, the door assembly, and the cover. The side sections are open to the interior of the center section. To maintain cleanliness inside the convertible hard side shelter from outside contaminants, the joints between the end panels and the center section corner posts, and the joints between the end and middle panels, are covered with flexible seals. When the convertible hard side shelter is in the deployed mode, personnel and equipment can enter and leave through the side section doors. 
     To convert the hard side shelter from the deployed mode to the transport mode, the covers are removed from over the side sections and allowed to hang vertically generally in the center section side planes. One edge of each side section door assembly is disconnected from the associated middle panel. If the door assembly has two door frames, the door frames are detached from each other instead of from a middle panel. The locking bars of the end and middle panels and the door assemblies are disengaged from the side section floors. The door assemblies are turned away from the center section such that they are not over the side section floors. Each side section floor is rotated to be parallel to and proximate a respective center section side plane. One or more winches may be used to assist rotating the side section floors. The winches are received in ISO locks in the center section corner posts. Slide locks or the like engage the center section frame to retain the side section floors vertical. 
     The door assemblies are then turned toward the center section and flat against the respective adjacent middle panels. The end and middle panels are turned to lie generally within a center section side plane and alongside the associated side section floor. The end and middle panels thus form the sides of the hard side shelter when it is in the transport mode. The locking bars on the end and middle panels then engage the center section frame to lock the end and middle panels to the center section frame. The result is a rigid hard side shelter having the envelope of an ISO cargo container. The convertible hard side shelter is then ready for handling and shipping in the same manner as an ISO container. 
     It is an important feature of the invention that the convertible hard side shelter is equipped with any of a wide variety of tools and machinery suitable to carry out particular desired tasks. For example, the convertible hard side shelter may be used as an office, kitchen, or medical station. A particularly important use for the convertible hard side shelter is as a tire maintenance workshop for heavy duty trucks. In that case, such items as an engine-driven generator, welding machine, air compressor, and tire repair tools are incorporated into the convertible hard side shelter. To assist moving such heavy items as the engine-generator set, the floor and bottom end door may have rails fixed to them. The engine-generator set is supported on a wheeled cart that rolls along the rails to locate the engine-generator set outside of the center section. Other tools and machinery may be arranged to fit entirely within the center section for transporting purposes and to be movable into the side sections when the hard side shelter is converted into the deployed mode. 
     In the preferred embodiment, a wall panel is built into the cart that supports the engine-generator set. The wall panel has peripheral seals that match the opening of the center section at the end door. When the cart is outside of the center section, the wall panel covers and seals the center section end opening. In that way, noise, dirt, and fumes associated with the outside environment and the engine-generator set are blocked from reaching inside the convertible hard side shelter. 
     The method and apparatus of the invention, using a center section that is based on a conventional ISO cargo container, thus enables a hard side shelter to be set up in the field. The convertible hard side shelter is convertible between a transport mode suitable for transporting, and a deployed mode suitable for a variety of functions such as a fully equipped tire maintenance workshop. 
     Other advantages, benefits, and features of the invention will become apparent to those skilled in the art upon reading the detailed description of the invention and studying the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the front end and road side of the convertible hard side shelter in the transport mode; 
         FIG. 2  is a perspective view of the back end and curb side of the convertible hard side shelter in the transport mode; 
         FIG. 3  is a broken view of the curb side of the convertible hard side shelter in the transport mode; 
         FIG. 4  is a perspective view of the front end of the convertible hard side shelter with the road side section in the deployed mode and the curb side section in a partially deployed mode; 
         FIG. 5  is a view similar to  FIG. 4  but showing the back end of the convertible hard side shelter; 
         FIG. 6  is a perspective view of the convertible hard side shelter in the fully deployed mode; 
         FIG. 7  is a broken top view of the convertible hard side shelter in the transport mode; 
         FIG. 8  is a broken top view of the convertible hard side shelter in the deployed mode; 
         FIG. 9  is a perspective view of the bottom of the convertible hard side shelter in the partially deployed mode; 
         FIG. 10  is a top view of the convertible hard side shelter showing it in the transport mode and equipped to function as a tire maintenance workshop; 
         FIG. 11  is a view similar to  FIG. 10 , but showing the convertible hard side shelter in the deployed mode; 
         FIG. 12  is a view similar to  FIG. 5 , but showing an open double end door of the center section; 
         FIG. 13  is a view similar to  FIG. 2  but showing the double end door of  FIG. 12  closed; 
         FIG. 14  is a broken perspective view showing the wall panel mounted to the cart that supports the engine-generator set; 
         FIG. 15  is a cross-sectional view on an enlarged scale taken along line  15 - 15  of  FIG. 7 ; 
         FIG. 16  is a perspective view showing winches used to assist rotating the side section floors; 
         FIG. 17  is a partial cross-sectional view similar to  FIG. 15 , but showing the cover of the invention in the deployed mode; 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention, which may be embodied in other specific structure. The scope of the invention is defined in the claims appended hereto. 
     General 
     Referring first to  FIGS. 1-3 , a convertible hard side shelter  1  is illustrated that includes the present invention. The convertible hard side shelter  1  is particularly useful for performing heavy duty repair work at remote locations. However, it will be understood that the invention is not limited to maintenance related applications. On the contrary, the invention is also eminently suitable for such diverse uses as food preparation, medical procedures, restrooms, and offices. In  FIGS. 1-3  and  7 , the convertible hard side shelter  1  is shown in a transport mode.  FIGS. 6 ,  8 , and  9  show the convertible hard side shelter in a deployed mode, as will be fully explained. In the preferred embodiment, the convertible hard side shelter  1 , when in the transport mode, has the exterior dimensions of a conventional International Standards Organization (ISO) cargo container. In the case, the convertible hard side shelter has an exterior length of 19 feet 10½ inches, a height of eight feet, and a height of eight feet. When in the transport mode, the convertible hard side shelter is handleable by a conventional pallet handling system as are known to persons working in the cargo container industry. Further, the convertible hard side shelters in the transport mode are stackable in the same way as conventional ISO cargo containers. To convert it from the transport mode to the deployed mode, the convertible hard side shelter  1  has a curb side section  3  and a substantially identical road side section  5 . The side sections  3  and fold and unfold relative to a center section  7 . When the side sections are folded into the center section  7 , the convertible hard side shelter has the exterior dimensions of an ISO cargo container mentioned above. 
     Center Section 
     The center section  7  is comprised of a sturdy frame  9  having horizontal and vertical beams. Looking especially at  FIGS. 4 and 9 , the particular frame  9  has bottom longitudinal beams  11 , bottom transverse beams  13 , top longitudinal beams  17 , and top transverse beams  19 . The frame further has four corner posts  15 A,  15 Bi  15 C, and  15 D collectively referred to as reference numeral  15 . The corner posts  15 A,  15 D and  15 B,  15 C define opposed vertical side planes of the center section that are indicated by reference numerals  20 ,  FIG. 7 . The corner posts  15 A,  15 B and  15 C,  15 D define center section end planes  22 . A rigid floor  21  covers the bottom beams  11  and  13 . A rigid roof  23  with an overhang covers the top longitudinal beams  17  and  19 . It is a feature of the convertible hard side shelter  1  that it is compatible with known pallet handling systems or load handling systems. For that purpose, the front end  24  of the center section  7  is manufactured with a strong bar  25  supported on its opposite ends by an A-frame  27 . Preferably, the A-frame  27  terminates at vertical beams  29  that tie into a top transverse beam  19 . The front end  24  of the center section is closed by a wall  34 . 
     Also parts of the convertible hard side shelter  1  are a pair of channels  30  under the frame bottom transverse beams  13 . The channels  30  are spaced and configured to suit conventional pallet handling systems. The channels cooperate with the bar  25  to enable efficient handling of the convertible hard side shelter by known pallet handling machinery. The back end  31  of the center section  7  is designed with an end opening  32  to provide access to the interior of the convertible hard side shelter  1 ,  FIG. 5 . In the illustrated construction, there is an end door  33  at the opening  32 . The end door  33  is comprised of a top door  35  that is hinged to a frame top transverse beam  19  for pivoting about a horizontal axis. A bottom door  37  is hinged to a frame bottom transverse beam  13  for pivoting about another horizontal axis. When the top and bottom doors  35  and  37 , respectively, are open, they are generally parallel to the roof  23  and floor  21 . When the doors  35  and  37  are open, the bottom door is held in place by heavy chains  38  secured to the frame  9 . The top door is held open by gas-activated shock absorbers  42 . When the top and bottom doors are closed, they lie generally in the center section end plane  22 . Both doors are locked in place when closed by associated locking bars  39 . The locking bars  39  may be constructed along the lines of the locking bars used on the doors of semi-trailers used in the trucking industry. The locking bars selectively engage and disengage tabs, not shown, on the frame corner posts  15 . 
     Cover 
     Turning briefly to  FIGS. 5 ,  7 , and  15 , the convertible hard side shelter  1  comprises a cover  66  associated with each side section  3  and  5 . Each cover  66  has a heavy tarp  78  hung from the top longitudinal beam  17  by suitable small plates and fasteners  80 . A long angle  18  is fastened to the tarp  78  at a distance from the top beam. Several C-clamps, not shown in  FIG. 5 ,  7 , or  15 , are built into the angle  18 . 
     Side Sections 
     Looking especially at  FIGS. 4-6 ,  8 , and  9 , the curb side section  3  and road side section  5  are comprised of a number of vertical panels collectively indicated at reference numeral  38  that are turnably mounted to each other. The curb side section and road side section are substantially identical. Accordingly, the following description of the curb side section is deemed adequate to also describe the road side section. 
     The panels  38  include a pair of end panels  40 , a pair of middle panels  41 , and a door assembly  43 . Each side section  3  and  5  also has a rigid floor  44 . Each end panel  40  has a first edge  45  that is turnably mounted to a center section corner post  15 . A second edge  47  of each end panel is turnably mounted to a first edge  49  of a middle panel  41 . A second edge  51  of each middle panel is turnably mounted to an opposite edge  53  or  55  of the door assembly  43 . The floor  44  is connected to the center section, such as to frame bottom longitudinal beam  11 , for rotating about a horizontal axis  26 . 
     In the illustrated construction, the door assembly  43  is made up of a first door frame  57  and a second door frame  59 . The first door frame  57  has a filler panel  60 . The second door frame  59  is depicted as having two side doors  69  that swing about respective vertical axes, but a single side door is also within the scope of the invention. If desired, one of the side doors  69  may be a bi-fold door. The first door frame  57  has the door assembly edge  53 , and the second door frame has the door assembly edge  55 . As illustrated, the first door frame has a second edge  61 , and the second door frame has a second edge  63 . The door assembly also includes latches  70  between the first and second door frames. The latches  70  enable the two door frame edges  61  and  63  to attach to and detach from each other. 
     The floor  44 , the pairs of end and middle panels  40  and  41 , respectively, and the door assembly  43  of each side section  3  and  5  are foldable to convert the convertible hard side shelter  1  between the transport and deployed modes. Each of the end and middle panels and door assemblies has at least one locking bar  65 . The locking bars  65  may be constructed generally along the lines of the locking bars  39  used on the center section end doors  35  and  37 . To prevent contaminants from passing between the center section corner posts  15  and the end panel edges  45 , flexible but massive seals, partially shown at reference numeral  68 , cover the joints between the corner posts and the end panel edges  45 . Similar seals, partially shown at reference numeral  71 , cover the joints between the end panel edges  47  and the middle panel edges  49 . 
     As mentioned,  FIGS. 6 ,  8 , and  9  show the convertible hard side shelter  1  in the deployed mode. In the deployed mode, the entire side sections  3  and  5  are outside of the center section side planes  20 . Specifically, the end panels  40  are parallel to the center section end plane  22 . The middle panels  41  are perpendicular to the end panels. The door assembly edges  61  and  63  are attached to each other, and the door assembly  43  is coplanar with the middle panels. The side section floor  44  is rotated about the horizontal axis  26  to be coplanar with the center section floor  21 . The locking bars  65  engage tabs in the side section floor to lock the end and middle panels and the door assembly to the side section floor. As a result, the side sections  3  and  5  become rigid with the center section  7 . The seals  68  and  71  prevent outside contaminants from entering the convertible hard side shelter through the joints between the center section center posts  15  and the end panels, or through the joints between the end and middle panels. 
     The cover  66  is extended between the center section roof  23  and the common top edges  67  of the end and middle panels  40  and  41 , respectively, and the door assembly  43 .  FIG. 17  shows the cover in the deployed mode. The tarp  78  is wrapped upwardly against the top longitudinal beam  17 , and the angle  18  is secured to the roof overhang by means of several C-clamps  82  that are built into the angle. Three free edges of the tarp are folded over the top edges  67  of the end and middle panels and door assembly and held in place, such as with hook and eye fastening tape. 
     When in the deployed mode, a preferred embodiment of the invention has a total exterior width of approximately 19 feet eight inches. The convertible hard side shelter  1  in the deployed mode thus provides a sealed interior space that is much larger than the interior space of the center section  7  alone. Access to the interior is through the end door  33  and the side doors  69  in the second door frame  59 . 
     Conversion 
     To convert the convertible hard side shelter  1  from the deployed mode of  FIGS. 6 ,  8 , and  9  to the transport mode of  FIGS. 1-3  and  7 , the covers  66  are removed from the side section end panels  40 , middle panels,  41 , and door assembly  43 . The C-clamps  82  are removed from the roof  23 , and the tarp  78  is allowed to hang vertically,  FIG. 15 . The locking bars  65  are disengaged from the side section floor  44 . The door assembly edges  61  and  63  are detached from each other. The end panels, middle panels, and door assembly are turned so as to not overlie the side section floors  44 . Each side section floor is rotated upwardly to lie parallel to and proximate a vertical side plane  20 . Alternatively, the floors  44  can be manually lowered with removable hand crank winches  84  that are fastened to the center of the roof  23  halfway between the forward wall and the rear wall for even distribution of the rigid floor. To assist rotating the side section floor, one or more winches  84  may be employed. See  FIG. 16 . The winches  84  are received in known ISO locks at the top ends of the corner posts  15 . Flexible cables  86  from the winches are removably hooked to the side section floor. 
     To retain the side section floor  44  vertical, it is provided with conventional slide locks  72 . As seen in  FIG. 15 , the slide locks  72  engage the top longitudinal beam  17 . However, the slide locks may engage the corner posts  15  instead, if desired. After the side section floor is properly retained, the cables  86  are unhooked from the floor, and the winches  84  are removed from the ISO locks. The winches and cables are also used to rotate the side section floors downwardly when the convertible hard side shelter  1  is converted back to the deployed mode. 
     The first door frame  57  is turned toward the center section  7  to lie flat against the adjacent middle panel  41 . The other door frame  59  is turned to lie flat against the other middle panel. The middle panels are turned to be coplanar with the end panels  40 . The end panels are turned on the center section corner posts is to lie alongside the associated side section floor  44 .  FIG. 15  shows heavy seals  101  on the end and middle panels that abut the top longitudinal beam  17 . 
     The entire door assembly  43  thus lies generally within the center section side plane  20 . Then the locking bars  65  are engaged with tabs  76  in the center section longitudinal beams  11  and  17 . The end and middle panels  40  and  41 , respectively, thus lock to the center section  7  and become rigid sides for the center section, and the entire convertible hard side shelter  1  has the envelope of an ISO container,  FIG. 7 . The convertible hard side shelter is then in the transport mode, ready to be handled by conventional pallet handling systems for stacking, shipping, and other handling operations. 
     Fire Maintenance Workshop 
     The convertible hard side shelter  1  is suitable for a wide variety of purposes. For example, it may be used to shelter military personnel at remote locations. It also is eminently useful for storing equipment and supplies at a remote site. An especially important use of the convertible hard side shelter is as a tire maintenance workshop. Looking at  FIG. 10 , the convertible hard side shelter is shown in the transport mode and equipped with machinery and tools for repairing heavy duty truck tires. The machinery may include a tire mounter and demounter schematically represented at reference numeral  73 . Other machinery includes a press  75 , air compressor  77 , air reservoir  79 , engine-generator set  81 , safety cage  83 , and tool box  85 . In addition, such auxiliary equipment as a heat pump  87  can be incorporated into the convertible hard side shelter. Other infrastructure may include a fluorescent lighting system and an overhead crane or a jib crane built into the center section  7 . 
     It is an important feature of the invention that some of the tire maintenance equipment is permanently installed in the convertible hard side shelter  1 . For instance, in  FIG. 10  the tire mounter and demounter  73  is installed to the center section floor  21  try a pivot pin  89 . The press  75  is installed to the floor by another pivot pin  91 . The pivot pins  89  and  91  enable the tire mounter and demounter and the press, respectively, to be permanently located within the center section  7 , but to have different angular positions.  10   FIG. 10 , all the equipment is shown in a storage location, fitting completely within the center section. 
     In  FIG. 11  the convertible hard side shelter  1  is shown in the deployed mode, and the tire maintenance equipment is shown in their working locations. Specifically, the tire mounter and demounter  73  are rotated 90 degrees about the pivot pin  89  relative to its stored location of  FIG. 10 . Similarly, the press  75  is at 90 degrees about its pivot pin  91  relative to its stored position.  FIG. 11  also shows a pair of rails  93  fixed to the center section floor  21  and matching rails  92  on the bottom door  37 . The engine-generator set  81  is placed on a wheeled cart  94  that rolls along the rails  92  and  93 . 
     The extra space provided by the side sections  3  and  5  enables the tire repair equipment to be spaced apart and thereby provide ample working space for personnel performing tire maintenance. On the other hand, when the tire repair operations are needed at a different place, the equipment is returned to the storage locations of  FIG. 10  for safe and efficient transport. A particularly important aspect of the present invention is that the center section opening  32  is coverable even when the end door  33  is open. Turning to  FIG. 14 , the center section back end  31  is shown with the end door open, thus providing access to the interior or the convertible hard side shelter  1 . For clarity, the top door  35  is not shown. The cart  94  for the engine-generator set  81  (not illustrated in  FIG. 14 ) is rolled onto the bottom door  37  along the rails  92  and  93 . To cover the opening  32 , a wall panel  96  is built into the cart  94  and rolls with it. The wall panel  96  has a size and shape that substantially matches the opening  32 . When the cart is rolled onto the bottom door, the wall panel covers the opening  32 . A seal  99  around the wall panel periphery helps to seal the interior of the convertible hard side shelter  1  from the noise and fumes of the engine-generator set  81  as well as from atmospheric pollutants. 
     Alternate Embodiments 
     As described thus far, the convertible hard side shelter  1  is constructed with the bar  25  and channels  30  that enable it to be handled by a conventional pallet loading system. The versatility of the invention is such that both center section ends  24  and  31  may be provided with end doors  33 , thereby eliminating the bar  25 .  FIGS. 12 and 13  show a convertible hard side shelter  1 ′ according to a second embodiment of the invention. The convertible hard side shelter  1 ′ is constructed with a double end door  95  at both ends  24  and  31 . It will be understood, of course, that a double end door  95  may be at only one end  24  or  31 , if desired. The double end door is comprised of top and bottom doors  35 ′ and  37 ′, respectively, that may be substantially identical to the doors  35  and  37  described previously in connection with  FIGS. 1-11 . The double end door further comprises a pair of outer doors  97 . Each outer door  97  is hinged to an associated corner post  15  for pivoting about a respective vertical axis. Each outer door includes at least one locking bar  65 . 
       FIG. 12  shows the double end doors  95  open. In that situation the top doors  35 ′ are generally parallel to the center section roof  23 , the bottom doors  37 ′ are generally coplanar with the center section floor  21 , and the outer doors  97  are generally parallel to the center section side planes  20  ( FIG. 8 ).  FIG. 13  shows the double doors closed. The top and bottom doors  35 ′ and  37 ′, respectively, are vertical and are within the center section end planes  22 . The outer doors are also generally within the end planes  22  and lie adjacent and outside of the top and bottom doors. The locking bars  65  securely lock the outer doors to the center section beams  13  and  19 . The double end doors thus effectively seal the interior of the convertible hard side shelter  1 ′ from outside contaminants such as sand and fumes. 
     CONCLUSION 
     In summary, the results and advantages of pallet handling systems for ISO cargo containers can now be more fully realized. The convertible hard side shelter provides both the ability to be transported and stored in the manner of ISO containers as well as to be converted into an expanded space for storing and working. This desirable result comes from using the combined functions of the side sections  3  and  5 . When in a transport mode, the side sections fold so as to form the sides of the center section  7  having the same exterior envelope as an ISO container. A floor  44  of each side section lies vertically alongside the folded end and middle panels  40  and  41 , respectively. The end and middle panels include locking bars  65  that engage the center section frame  9 . The center section may include the bar  25  and channels  30  used with conventional pallet handling systems. When in a deployed mode, the side sections unfold. The side sections floors rotate to be coplanar with the center section floor  21 . The end and middle panels and the door assemblies  53  lock to the side section floors to render the side sections rigid with the center section. Access to the interior of the convertible hard side shelter is through the side doors  69 . The convertible hard side shelter is ideal for use as a portable tire maintenance workshop. 
     It will also be recognized that in addition to the superior performance of the convertible hard side shelter, its construction is such as to provide increased economy related to the transportation and storage of personnel and equipment. Also, because it follows a simple and rugged design, the convertible hard side shelter gives many years of service life with but minimal maintenance. 
     Thus, it is apparent that there has been provided, in accordance with the invention, a convertible hard side shelter that fully satisfies the objects, aims, and advantages set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims.