Abstract:
The present invention provides a system, or kit, of injection molded panels having integrated connectors which combine to form an enclosure, commonly in the form of a utility shed. The bilaterally symmetrical panels are formed of injection molded plastic to interlock with one another without the need for separate I-beam connectors. The ends of the wall panels have cavities to accept both roof and floor outwardly projecting interlocking posts for interlocking cooperative engagement which serve to rigidly connect the components together. The bilateral symmetry of the wall, roof, floor and door components also minimizes component shapes and simplifies enclosure construction.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to an enclosure constructed of plastic structural panels. More specifically, the present invention relates to a modular construction system utilizing injection molded plastic structural panels having integrated connectors to construct variably sized storage sheds using the same components. 
     BACKGROUND INFORMATION 
     Enclosures such as storage sheds are a necessity for lawn and garden care, as well as general all-around home storage space. Typically, garden tools and equipment are found either stacked into a corner of the garage, or bundled together and covered with a tarpaulin to protect them from the elements. During the off-seasons, lawn mowers, tillers and snow equipment often consume the available floor space of a garage, forcing the homeowner to park his automobile outside. 
     The prior art has proposed a number of different panel systems, or kits comprising blow molded or extruded panels and connector members for forming a wide variety of structures. Due to manufacturing limitations blow molded and extruded plastic components cannot be formed with the integral cross-bracing ribs or the intricate shapes and sharp corners required for integrated connectors that are possible with injection molding. Typically, such systems require extruded metal or plastic connector members having a specific cross-sectional geometry that facilitate an engagement between such members and one or more plastic panels having a complimentary edge configuration. 
     A particularly common structure for the connector members is the I-beam cross section. The I-beam defines free edge portions of the connector member which fit within appropriately dimensioned and located slots in the panel members. U.S. Pat. No. D-371,208 teaches a corner extrusion for a building sidewall that is representative of the state of the art I-beam connector members. The I-beam sides of the connector engage with the peripheral edge channels of a respective wall panel and thereby serve to join such panels together at right angles. Straight or in-line versions of the connector members are also included in the kits to join panels in a coplanar relationship to create walls of varying length. 
     Extruded components generally require hollow longitudinal conduits for connection and strength. Due to the nature of the manufacturing process the conduits are difficult to extrude in sections long enough for structural panels. Thus, they require connectors to achieve adequate height for utility shed walls. A common structure for connecting extruded members has a center I-beam with upper and lower protrusions for engaging the conduits. However, wall panels utilizing I-beam connectors are vulnerable to buckling under loads and may have an aesthetically unpleasing appearance. Moreover, roof loads from snow and the like may cause such walls to bow outwardly due to the clearances required between the connectors and the internal bores of the conduits. U.S. Pat. No. 6,250,022 discloses an extendable shed utilizing side wall connector members representing the state of the art. The connectors have a center strip with hollow protrusions extending from its upper and lower surfaces along its length. The protrusions are situated to slidably engage the conduits located in the side panel sections to create the height needed for utility shed walls. 
     The aforementioned systems can also incorporate roof and floor panels to form a freestanding enclosed structure such as a utility shed. U.S. Pat. Nos. 3,866,381; 5,036,634; and 4,557,091 disclose various systems having inter-fitting panel and connector components. Such prior art systems, while working well, have not met all of the needs of consumers to provide structural integrity combined with modularity and aesthetic appearance. Paramount among such needs is a panel system which eliminates the need for I-beam connectors creating enclosure walls which resist panel separation, buckling, racking and weather infiltration. It is also desirable for the wall formed by the panels to tie into the roof and floor in such a way as to unify the entire enclosure. Also, from a structural standpoint, a door must be present which can be easily installed after assembly of the wall and roof components, is compatible with the sidewalls, and provides dependable pivoting door access to the enclosure. All known prior art requires the roof to be partially disassembled before the doors can be installed. 
     There are also commercial considerations that must be satisfied by any viable enclosure system or kit; considerations which are not entirely satisfied by state of the art products. The enclosure must be formed of relatively few component parts that are inexpensive to manufacture by conventional techniques. The enclosure must also be capable of being packaged and shipped in a knocked-down state. In addition, the system must be modular and facilitate the creation of a family of enclosures that vary in size but share common, interchangeable components. 
     Finally, there are ergonomic needs that an enclosure system must satisfy in order to achieve acceptance by the end user. The system must be easily and quickly assembled using minimal hardware and requiring a minimal number of tools. Further, the system must not require excessive strength to assemble or include heavy component parts. Moreover, the system must assemble together in such a way so as not to detract from the internal storage volume of the resulting enclosure or otherwise detract from the internal storage volume of the resulting enclosure or otherwise negatively affect the utility of the structure. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The present invention provides a system, or kit, of injection molded panels having integrated interlock connectors which combine to form an enclosure, commonly in the form of a utility shed. The bilaterally symmetrical panels are formed of injection molded plastic to interlock with one another without the need for separate I-beam connectors. The ends of the wall panels have sockets to accept both roof and floor outwardly projecting interlocking posts for cooperative engagement which serves to rigidly connect the components together. 
     The system incorporates a minimum number of components to construct a heavy duty enclosure by integrally forming the connectors into the injection molded panels. This minimizes the need for separate extruded or molded connectors to assemble the enclosure. The bilateral symmetry of the wall, roof, floor and door components also minimizes component shapes and simplifies enclosure construction. Injection molding the wall panels allows them to be formed with adequate height for a walk-in enclosure, eliminating the need for stacking panels to achieve such a height. Injection molding also allows the panels to be formed with integral cross-bracing, ribs and gussets for increased rigidity when compared to blow molded or extruded panels. 
     In one embodiment, the enclosure system utilizes two types of wall panel construction: the first being utilized for the side walls, and the second being used for the rear wall and the door assembly. The embodiment also utilizes one construction of bilaterally symmetrical roof panel and one construction of bilaterally symmetrical floor panel; each of the assemblies having a median axis of symmetry with one panel on each side of the axis rotated 180° in relationship to the other. The system further includes a door assembly which slides into place after the walls and roof have been fully assembled. The floor of the system is constructed to allow optional plastic floor supports or wooden floor joists to be added to the plastic floor panels, and optional steel supports to be added to the roof panels further increasing the structural integrity of the enclosure. The same components are used to create sheds of varying size. The assembly of the system requires minimal hardware and a minimum number of hand tools. 
     Accordingly, it is an objective of the present invention to provide a modular panel system having integrated interlocking connectors for creating enclosures of varying dimension using common components. 
     A further objective is to provide a modular panel system with integrated interlocking connectors which accommodates injection molding plastic formation of the panel components for increased structural integrity. 
     Yet a further objective is to provide a modular panel system enclosure in which sides, roof, and floor are integrally interlocked without I-beam connectors. 
     Another objective is to provide an enclosure constructed of modular panels having a door assembly which allows door installation after all other parts are assembled. 
     Yet another objective is to provide a modular panel system which reduces the number of components required to assemble an enclosure and simplifies construction. 
     Still yet another objective is to provide a heavy duty enclosure constructed of modular panels constructed and arranged to allow wood, plastic or steel supports to be easily incorporated into the panels. 
     An even further objective is to provide an enclosure kit for a utility shed in which modular panels are provided to the consumer in a disassembled state. 
     Other objectives and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a perspective view of an enclosure constructed using the instant enclosure system; 
         FIG. 2  is an exploded view of the enclosure shown in  FIG. 1 ; 
         FIG. 3  is a perspective view of one embodiment of the floor assembly utilized in the instant invention; 
         FIG. 4  is a partial perspective view of the floor assembly illustrating insertion of the optional plastic floor supports; 
         FIG. 4A  is a cross-sectional view along lines  1 — 1  of  FIG. 4  illustrating the cooperation between the floor panel and the plastic floor supports. 
         FIG. 5  is a partial perspective view of the floor assembly illustrating the insertion of the optional floor joists; 
         FIG. 5A  is a perspective view of the floor assembly illustrating the sliding engagement of the floor panels; 
         FIG. 6  is a bottom view of the floor assembly illustrating the cross-bracing; 
         FIG. 7  is a partial perspective view illustrating assembly of the first side wall panel to the floor assembly; 
         FIG. 7A  is a partial enlarged view illustrating the cooperative engagement between the panels and the dowel; 
         FIG. 8  is a partial perspective view further illustrating assembly of the side wall panels; 
         FIG. 9  is a partial cross sectional view illustrating the locking engagement between the dowel and adjacent wall panels; 
         FIG. 10  is a partial perspective view illustrating assembly of the rear wall panels; 
         FIG. 11  is a partial perspective view further illustrating assembly of the rear wall panels; 
         FIG. 12  is a partial perspective view further illustrating assembly of the side wall panels; 
         FIG. 13  is a partial perspective view further illustrating assembly of the side wall panels; 
         FIG. 14  is a perspective view of the roof panels utilized in the instant invention; 
         FIG. 15  is a perspective view of the roof panels utilized in the instant invention illustrating insertion of the optional steel roof support; 
         FIG. 16  is a perspective view of the assembled roof panels illustrating insertion of the weatherstrip seal; 
         FIG. 17  is a partial cross sectional view illustrating the cooperation between the weatherstrip seal and the roof panels; 
         FIG. 18  is a perspective view illustrating installation of the roof assembly; 
         FIG. 19  is a partial exploded view illustrating the door assembly of the instant invention; 
         FIG. 20  is a perspective view illustrating the installation of one of the doors; 
         FIG. 21  is a partial perspective view of the enclosure with enlarged partial views illustrating assembly of the hinges; 
         FIG. 22  is a partial view illustrating assembly of one of the door handles utilized in the instant invention; 
         FIG. 23  is a partial view illustrating assembly of one of the door handles utilized in the instant invention; 
         FIG. 24  is a partial view illustrating assembly of one of the door latch housings utilized in the instant invention; 
         FIG. 25  is a partial view illustrating assembly of one of the door latch pins utilized in the instant invention; 
         FIG. 26  is a partial sectioned view illustrating the cooperation of the optional shelves with the side panels in the instant invention; 
         FIG. 27  illustrates an alternative embodiment of the instant invention; 
         FIG. 28  is an exploded view of the alternative embodiment shown in FIG.  27 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described a presently preferred embodiment with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiments illustrated. 
       FIGS. 1 and 2  which are now referenced show an isometric and exploded view of the heavy duty enclosure, generally referenced as  10 , according to a preferred embodiment of the present invention. The enclosure is made up of a floor assembly  100 , left and right side wall assemblies  200 , rear wall assembly  300 , roof assembly  400  and door assembly  500 . In the preferred embodiment, the panels comprising the assemblies are formed of, but not limited to, a suitable plastic such as polypropylene, through the process of injection molding. The result is that the panels comprising the floor  100 , walls  200 - 300 , roof  400 , and doors  500  of the enclosure  10  are formed as unitary panels with integral interlocking connectors, and cross bracing. Strengthening ribs  202  and gussets  204  are formed within the inner surfaces of the wall panels  200 - 300  in order to enhance rigidity of the panels while leaving the external surface in a generally smooth condition for aesthetic purposes, as shown in FIG.  1 . The panels are utilized to construct the bi-laterally symmetrical floor assembly  100 , left and right wall assemblies  200 , rear wall assembly  300 , door assembly  500 , and roof assembly  400  using a minimal number of components. 
     Referring to  FIGS. 3-7 , the enclosure includes a pair of like-constructed floor panels  102 . Each panel has a top surface  104 , bottom surface  106 , locking edge  108 , ramp edge  110 , and two closed edges  112  and  114 . Adjacent to each of the closed edges is a means of attaching the floor assembly to the wall assemblies illustrated as a plurality of interlocking posts  116  extending upwardly from the top surface  104 . The interlocking posts  116  are constructed and arranged to cooperate with sockets  210  located at each longitudinal end of the first structural wall panels  202 . Adjacent to each of the ramp edges  110  is a pair of generally cylindrical hinge pins  128  extending upwardly. The hinge pins  128  cooperate with the panels  502  to allow rotational movement. A series of spaced apart tubes  118  extend through each floor panel  102  under the top surface  104  and between the locking edge  108  and the ramp edge  110 . The tubes  118  are sized to accept optional plastic floor supports  130  or wooden floor joists  120  ( FIGS. 4-7 ) to add increased weight capacity and stability to the enclosure  10 . The preferred cross-section of the plastic floor support  130  is illustrated in  FIG. 4A  as generally having an I-beam shape. The plastic floor support is constructed and arranged with the upright portion of the beam split like a Y to allow a fastener to secure the floor support to the floor panel without affecting the strength of the beam. Other suitable cross-sectional shapes well known in the art capable of allowing a fastener to secure the shape to the floor panel could be substituted for the preferred embodiment. Along the locking edge  108  of each bottom panel  102  is a series of spaced apart fingers  122  and recesses  124  for attaching the panels together into a floor assembly  100 ; each of the fingers being provided with at least one countersank aperture for receiving a fastener (not shown). The fingers  122  and recesses  124  are constructed and arranged so that the fingers  122  overlap and mateably engage the recesses  124  and the fasteners secure the panels together in an inter-fitting engagement with their respective top surfaces  104  in a coplanar arrangement. The bottom surface  106  ( FIG. 6 ) illustrates the cross-bracing  128  facilitated by injection molding of panels. Injection molding offers significant strength and stability advantages over blow-molding as utilized in the prior art. In this manner the enclosure of the instant invention is capable of handling a significant amount of weight as compared to blow molded or extruded enclosures. 
     Referring to  FIGS. 7-9 , a structural side wall panel  202  is shown. The structural side wall panel  202  constitutes one of a plurality of like-configured panels in the system used to construct the left and right side wall assemblies  200 . The structural side wall panels  202  are each configured having a first longitudinal end  208  including an integrally formed attachment means illustrated as a plurality of sockets  210 . A second longitudinal end  212  also includes an integrally formed attachment means also illustrated as a plurality of sockets  210 . The sockets are generally constructed and arranged to cooperate with either a floor assembly  100  or a roof assembly  400 . To facilitate mechanical connection with other inverted first structural panel members  200  in a co-planar relationship the panels are provided a first horizontal edge  214  constructed with an attachment means illustrated as a semi-circular conduit  216  extending from about the first longitudinal end  208  to about the middle portion of the edge  214 . Centrally located within the semi-circular conduit  216  is a generally circular aperture  218  for accepting a dowel  220 . The second horizontal edge  222  is constructed generally flat extending inwardly to a depending semi-circular conduit  224 , the semi-circular conduit  224  extending from about the mid-portion of the panel to about the second horizontal end  212 . The conduit  224  is arranged to cooperate with a rear wall panel member  302  or a door-panel member  502  having a complimentary semi-circular conduit in a perpendicular relationship. Continuing with regard to  FIGS. 7-9 , the outer surface  228  ( FIG. 2 ) of the panels  202  are constructed generally smooth having a plurality of inwardly bowed surfaces  230  for added strength and aesthetic appearance. The inside of the panel  232  is constructed with a plurality of ribs  204  extending from the first edge  214  across the panel  202  to the second edge  222 . Each of the ribs  204  are provided with a plurality of gussets  206  to further strengthen the panel  202 . The ribs  204  and gussets  206  increase the structural integrity of the enclosure  10  by preventing the panels  202  from bowing or bending inwardly or outwardly, and thus, adversely affecting the appearance or operation of the enclosure  10 . The reinforced ribs also provide support for optional shelves  600  (FIG.  23 ). The construction of the ribs  204  allows shelving to extend across the span of the shed; thereby dividing the load between two walls and eliminating the cantilever effect of attaching a shelf to a single wall surface. 
     The side wall panels  202  are attached to the interconnected floor panels  102  by sliding either of the first or second longitudinal ends  208 ,  212  over a plurality of the interlocking posts  116 . After locking the first panel into place, each corresponding panel is rotated 180° in relation to the prior panel and slid into place. The sockets  210  in each end of the panels  202  correspond in shape and size to that of the interlocking posts  116  and spring tabs  126  ( FIG. 3 ) integrally formed into the interlocking posts  116  and align with apertures  234  in the sockets  210  to engage the side wall panels  202 . The result is a positive mechanical connection between the wall panels  200  and the floor assembly  100  with the first wall panel being attached to the floor assembly  100  with the first longitudinal end  208  downward. The second panel is thereafter attached inverted from the first with the second longitudinal end  212  downward (FIG.  8 ). Secured to the longitudinal end  212  of the conduit  224  of the first panel is a hinge pin receiver  236  constructed and arranged to cooperate with a roof assembly hinge pin  428  to allow rotational movement of the door assembly  500 . Secured to the longitudinal end  212  of the conduit  224  of the second panel is a hinge pin connector  238  constructed and arranged to cooperate with a floor assembly hinge pin  128  (FIG.  3 ). 
     It will be appreciated that the purpose of the semi-circular conduits  216 ,  224  are to align two panels in a co-planar or perpendicular relationship and to facilitate their mechanical connection via the dowel  220 . The semi-circular conduits  216 ,  224  are brought into an overlapping relationship wherein a dowel pin  220  enters the corresponding aperture  218  in each conduit (FIG.  7 A). The result is a mechanically secure connection between the two panels (FIG.  9 ). The overlapping edges between the panels as described above provide a secure connection and offer several advantages. First, the design allows the panels to be connected without the need for I-beam connectors. Second, the design allows the panels to be formed at sufficient height for a walk-in enclosure by creating a positive lock that prevents separation of the panels. Third, the design maintains alignment of the panels in the same plane and prevents bowing or bending of either panel relative to one another. The resultant wall created by the interlocking wall-panels benefits from high structural integrity and reliable operation. 
     Referring to  FIGS. 10-11 , assembly of the structural rear wall panels is shown. The rear wall panel  302  constitutes one of a plurality of like-configured panels in the system used to construct the rear wall assembly. The rear wall panels  302  are each configured having a first longitudinal end  308  including an integrally formed attachment means illustrated as a plurality of sockets  310 . A second longitudinal end  312  includes an integrally formed attachment means also illustrated as a plurality of sockets  310 . The sockets are generally constructed and arranged to cooperate with either a floor assembly  100  or a roof assembly  400 . To facilitate mechanical connection with other inverted wall panel members  300  in a coplanar or perpendicular relationship, the panels are provided a first horizontal edge  314  constructed with a semi-circular conduit  316  extending from about the first longitudinal end  308  to about the middle portion of the edge. Centrally located within the semi-circular conduit  316  is a generally circular aperture  318  for accepting a dowel  220 . The second horizontal edge  322  is constructed generally the same as the first horizontal edge  314  with the exception that the semi-circular conduit  324  extends from about the mid-portion of the panel to the second horizontal end  312 . The conduits  316 ,  324  are arranged to cooperate with other panel members having a complimentary semi-circular conduit in a co-planar or a perpendicular relationship. Hinge cap  336  is constructed and arranged to cooperate with the longitudinal end of the semi-circular conduits and a roof assembly or floor assembly hinge pin  428 . 
     Continuing with regard to  FIGS. 10-11 , the outer surface  328  ( FIG. 2 ) of the panels  302  are constructed generally smooth having a plurality of inwardly bowed surfaces  330  ( FIG. 2 ) for added strength and aesthetic appearance. The inside of the panel  332  is constructed with a plurality of ribs  304  extending from the first edge  314  across the panel  302  to the second edge  322 , each of the ribs  304  are provided with a plurality of gussets  306  to further strengthen the panel  302 . The ribs  304  and gussets  306  increase the structural integrity of the enclosure  10  by preventing the panels  302  from bowing or bending inwardly or outwardly and thus, adversely affecting the appearance or operation of the enclosure  10 . 
     The rear panels  302  are attached to the interconnected floor panels  102  and the installed left side panels  202  by sliding the first longitudinal end  308  of a rear wall panel downward over a dowel  220  and aligning the semi-circular conduits. A hinge cap  336  is pushed into a corresponding cavity located in the second longitudinal end  312  of the panel  302  for engagement with the roof assembly  400 . The second rear panel is slid downward simultaneously engaging the inserted interlocking post  338  and the hinge pin in the floor assembly via a hinge cap  336  inserted into the semi-circular conduit and engaging the first rear panel via the dowel  220 . Spring tabs  126  integrally formed into the inserted interlocking post  338  and hinge caps  336  align with apertures  334  in the panels  302  for engagement. The result is a positive mechanical connection between the side panels  200 , rear panels  300  and the floor assembly  100 . 
     Referring to  FIGS. 12-13 , the first right side wall panel  202  is attached to the interconnected floor panels  102  and the assembled rear wall panels  302  by sliding the first longitudinal end  208  over a plurality of the interlocking posts  116 . The second corresponding right side wall panel  202  is rotated  1800  in relation to the first panel  202  and slid into place over the interlocking posts  116  next to the first panel. The sockets  210  in the ends of the panel  202  corresponding in shape and size to that of the interlocking posts  116  and spring tabs  126  ( FIG. 3 ) integrally formed into the interlocking posts  116  align with apertures  234  in the sockets  210  to engage the side wall panel  202  the result is a positive mechanical connection between the wall panels  200  and the floor assembly  100 . The first assembled right side wall panel  202  is attached to the floor assembly  100  with the first longitudinal end  208  downward and the second assembled panel is thereafter attached with the second longitudinal end  212  downward (FIG.  13 ). Secured to the longitudinal end  212  of conduit  224  of the first panel is a hinge pin receiver  238  constructed and arranged to cooperate with a roof assembly hinge pin  428 . Secured to the longitudinal end  212  of the conduit  224  of the second panel is a hinge pin connector  236  constructed and arranged to cooperate with a floor assembly hinge pin  128  and the door assembly  500  to allow rotational movement of the doors. 
     Referring to  FIGS. 14-16 , the enclosure  10  includes a pair of like-constructed roof panels  402 . Each panel has a top surface  404 , bottom surface  406 , locking edge  408  and three closed edges  410 ,  412  and  414 . Closed edge  412  is provided with a drip edge  413  constructed and arranged to to direct water away from the from closed edge  412 . Adjacent to the two side closed edges  410 ,  414  is a plurality of interlocking posts  416  extending downwardly from the top surface  404 . The interlocking posts  416  are constructed and arranged to cooperate with sockets  210  located at each longitudinal end of the first structural wall panels  202 . A series of spaced apart structural tubes  418  ( FIG. 15 ) extend through each roof panel  402  under the top surface  404  and between the locking edge  408  and the closed edge  412 . Along the locking edge  408  of each roof panel  402  a portion of the tubes  418  extend outward from the locking edge to function as interlocking posts  430 , the remainder of the tubes being configured as sockets  432  for receiving the interlocking posts  430  for attaching the like-configured panels together into a roof assembly  100 . The center tube  418 , being constructed and arranged to accept a connector  434  as well as an optional steel roof support  420  (FIG.  15 ), adds increased weight capacity and stability to the roof assembly  400  of the enclosure  10 . The roof panels  402  are slid together until the spring tabs  436  integrally formed into the interlocking posts  430  engage corresponding apertures  438  formed in the sockets  432 . A weatherstrip  440  is utilized to seal the roof assembly seam against leakage. Starting at one side of the roof assembly  400 , the weather strip  440  is fed into the groove  442  ( FIG. 17 ) formed by connecting the two roof panels  402  until it is centered. 
       FIG. 17  shows the resilient weatherstrip seal  440 , which takes the general cross section of a flared U with an arrow extending downwardly from the apex of the radius. The weatherstrip seal  440  is constructed from a resilient material allowing the free edges  444  to be spread outwardly as the strip  440  is slid into place, creating a watertight seal between the top surface  404  of the roof panels  402  and the weatherstrip  440 . Moreover, the roof panel  402  construction provides an elevated position for the weatherstrip  440  allowing water to be quickly directed away from the weatherstrip. It is also understood and anticipated that other suitable types of weatherstrips and/or sealants well known in the art could replace the illustrated weatherstrip seal. 
     Assembling the roof assembly onto the enclosure is shown in FIG.  18 . It should be appreciated that this step is performed before the doors are assembled to the enclosure. This eliminates the tedious task of aligning the doors as the roof is attached to the structure, thereby simplifying assembly over the prior art. The roof assembly  400  is placed over the assembled left, right, and rear walls and lowered into place. The interlocking posts  416  are lined up with the corresponding sockets  210  in the wall panels  202 . The roof assembly  400  is secured in place by pulling downward on the roof until the spring tabs  446  integrally formed into the interlocking posts  416  engage corresponding apertures  234  formed in the sockets  210  and back panel tabs (not shown) interlock with the roof assembly  400 . The result is a positive mechanical connection between the side panels  200 , rear panels  300  and the roof assembly  400 . 
     Referring to  FIGS. 19-21 , the enclosure includes a door assembly including a pair of door panels, a hinge means, a door handle assembly, and a latch assembly. The door panel  502  constitutes one of a plurality of like-configured panels in the system used to construct the door assembly. The door panels  502  are configured each having a first longitudinal end  508  including at least one integrally formed socket  510 . The socket  510  is generally constructed and arranged to cooperate with a hinge cap  336  having a C-shaped annular portion. The door panels are also configured having a second longitudinal end  512  including an integrally formed C-shaped annular hinge portion  524 . To facilitate mechanical connection with other side wall panel members  200  in a hinging relationship, the panels are provided a first horizontal edge  514  constructed with a semi-circular conduit  516  extending from about the first longitudinal end  508  to about the middle portion of the edge. The hinge cap  336 , integrally formed hinge portion  524 , and the semi-circular conduit  516  each contain at least one hinge means illustrated as a C-shaped annular portion  518  having an open side  520  constructed and arranged to accept a hinge pin  128 ,  428  or a dowel pin  220  and to cooperate with a hinge clip  540  to close the annular cavity  518  and allow pivoting movement of the door panel  502 . The second horizontal edge  522  is constructed generally flat with the exception of a optional ledge  532  extending the full length of the panel. The optional ledge  532  may be attached by any suitable fastening means well known in the art or may be integrally formed with the panel. The door panels  502  are also provided with an upper and lower sliding latch mechanism  534  and left and right door handles  536 ,  538 . 
     Continuing with regard to  FIGS. 19-21 , the outer surface  528  of the panels  502  are constructed generally smooth having a plurality of inwardly bowed surfaces  530  for added strength and aesthetic appearance. The inside of the panel  532  is constructed with a plurality of ribs  504  extending from the first edge  514  across the panel  502  to the second edge  522 . Each of the ribs  504  may be provided with a plurality of gussets (not shown) to further strengthen the panel  502 . The ribs  504  increase the structural integrity of the enclosure  10  by preventing the panels  502  from bowing or bending, inwardly or outwardly, and thus, adversely affecting the appearance or operation of the enclosure  10 . 
     The door panels  502  are attached to the interconnected floor panels  100 , left and right side wall assemblies  200 , and roof panels  400  by sliding the respective hinge cap  336  into the corresponding cavity  510  located in the first end  508  of the door panels, the second door panel being rotated 180° in relationship to the first. Either door panel  502  is aligned with the hinge pins by sliding it horizontally into place over the respective pins and engaging the hinge clips  540  (FIGS.  20 - 21 ). The body of the hinge clip  540  is generally concave and rectangular and includes spring tabs  542  located at each end adapted to fit within the respective hinge caps to secure the door panels to the hinge pins and facilitate independent rotational movement of each door. It should be appreciated that this construction allows the doors to be installed or removed without disassembling or partially disassembling other components from the enclosure  10 . The construction also provides economic advantage allowing inexpensive hinge components to be easily removed and replaced in the event they become damaged while reusing the same panel. The door panels are also provided with removable and replaceable door latching mechanisms including slide latches  534 , left door handle  536  and right door handle  538 . 
     Referring to  FIGS. 22-23 , installation of the left door handle  536  and right door handle  538  is illustrated. The door handles are constructed and arranged to allow simple push-in installation. The handles are merely pushed into apertures  544  contained in door panels  502  until the spring clips  542  engage the back surface  532  of panel  502 . In this manner the door handles can be installed and removed as need without the need for tools or screw type fasteners. The handles are also provided with lock apertures allowing the contents contained within the enclosure to be secured with a padlock or the like. 
     Referring to  FIGS. 24-25 , installation of the upper and lower door latches is illustrated. The door latches are constructed and arranged to allow simple push-in installation. The latch housings  552  are merely pushed into apertures  546  located adjacent to edge  522  in the door panels  502  until the spring clips  548  engage the back surface  532  of panel  502 . Thereafter, the one end of the door latch pin  554  is inserted through the housing  552  and slid downwardly until the spring clip  550  is snapped into place. In this manner the door latches can be installed and removed as needed without the need for tools or screw type fasteners. The latch pin  554  can be slid outwardly to engage the roof assembly  400  or the floor assembly  100  to secure the contents contained within the enclosure  10 . 
     Referring to  FIGS. 27-28 , an alternative embodiment of the present invention is shown wherein the enclosure is made larger by increasing the size of the floor panels  602 , the roof panels  702 , and adding a rear wall panel  302  between side wall panels  202 . In this manner the same construction can be utilized to build structures of varying size utilizing substantially the same components. 
     All patents and publications mentioned in this specification are indicative of the levels of those skilled in the art to which the invention pertains. All patents and publications are herein incorporated by reference to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference. 
     It is to be understood that while a certain form of the invention is illustrated, it is not to be limited to the specific form or arrangement herein described and shown. It will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is shown and described in the specification. 
     One skilled in the art will readily appreciate that the present invention is well adapted to carry out the objectives and obtain the ends and advantages mentioned, as well as those inherent therein. The embodiments, methods, procedures and techniques described herein are presently representative of the preferred embodiments, are intended to be exemplary and are not intended as limitations on the scope. Changes therein and other uses will occur to those skilled in the art which are encompassed within the spirit of the invention and are defined by the scope of the appended claims. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are obvious to those skilled in the art are intended to be within the scope of the following claims.