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CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 12/347,696 filed on Dec. 31, 2008. U.S. patent application Ser. No. 12/347,696 is a divisional of U.S. patent application Ser. No. 11/828,002 filed on Jul. 25, 2007, which is a continuation of U.S. patent application Ser. No. 11/434,483, filed on May 15, 2006, which is a continuation of U.S. patent application Ser. No. 10/460,046, filed on Jun. 12, 2003. U.S. patent application Ser. No. 10/460,046 claims priority to U.S. Provisional Patent Application Ser. No. 60/388,514, filed on Jun. 12, 2002. The entire content of each of the priority applications is hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to animal enclosures. More particularly, the present pet enclosure includes a collapsible one-piece frame that provides for easy set up of the enclosure as well as portability without the need to keep track of multiple pieces. Advantageously, the enclosure includes a completely removable and washable fabric cover. 
       BACKGROUND OF THE INVENTION 
       [0003]    Many pet owners enjoy taking their pet along with them when they travel. For example, when taking an extended road trip, many pet owners like to have their pet&#39;s companionship for the trip. Taking the pet along is often preferable to hiring someone to take care of the pet or putting the pet in a kennel. Many pets suffer separation anxiety when their owner is away. The anxiety can cause the pet to chew on furniture, urinate on the carpet, and generally wreak havoc around the house. When the owner returns, the damage causes the owner unnecessary aggravation and repair expense. 
         [0004]    Several pet carriers are available that owners can use to conveniently transport their pets. For example, U.S. Pat. Nos. 6,076,485 and 6,155,206 disclose collapsible pet carriers. However, when the owner arrives at his or her destination, often there is no convenient area in which to leave the pet. Pet carriers, such as those described in the above patents, are designed to be small and easy to carry. Consequently, they are generally confining for the pet. They do not have much interior space in which the pet can stretch out. 
         [0005]    Leaving the pet in a car is dangerous to the pet. If the temperature outside the car is cold, then the car interior will be cold and the pet may become sick. Conversely, if it is a warm day and the sun is shining, the sun&#39;s radiation can cause the interior of the car to reach dangerously hot temperatures. Further, while in the car the pet may suffer from separation anxiety. The pet may then cause the same problems described above. 
         [0006]    If the owner is visiting a friend&#39;s or relative&#39;s home, he or she may sometimes bring the pet into the home. However, many homeowners are sensitive to the problems that pets can cause, such as odors or damage from chewing or scratching. Further, some homeowners are allergic to pet dander, which pets usually leave behind on carpet and/or furniture. Therefore, letting the pet roam free indoors is not always possible. Further, many homes do not have suitable outdoor areas in which the pet may roam. Homes located in heavily populated urban areas often do not have enough outdoor area for the pet to occupy. Homes in more rural areas may not have fencing to contain the pet. The pet could thus wander off and be lost or struck by a car. 
         [0007]    A number of portable pet enclosures are available to pet owners. Pet owners can thus bring their pets along with them almost anywhere they go. When the owner arrives at his or her destination, he or she sets up the enclosure, indoors or out, and places the pet inside. The pet is safely contained and cannot wander off. The enclosure is ventilated to prevent the temperature inside from becoming too hot. If the enclosure is placed indoors, the enclosure prevents direct contact between the pet and the surroundings, thus reducing odors or dander that the pet might otherwise leave behind. 
         [0008]    U.S. Pat. No. 5,335,618 (the &#39;618 patent) discloses an example of a collapsible animal enclosure. The enclosure has a house unit  10  with spaced side walls  14  and a roof  16  of pliable material, and opposite ends  20 ,  22  forming an enclosed area for housing an animal. Each end wall has an opening  24 ,  26  for allowing entry to and exit from the enclosure. Support bows  28  extend transversely across the side walls and roof for holding the side walls and roof in an open, spread apart condition. The house unit is convertible between a use configuration in which the opposite ends are spread a maximum distance apart and a collapsed configuration in which the ends are pushed inwardly towards one another, collapsing the pliable material between the ends in an accordion-like manner. Longitudinal spreader bars  32  disposed at either end in pockets  34  at opposite ends of the house unit maintain the house unit in the use configuration. An extended run unit  12  of similar construction to the house unit is releasably securable to one end of the house unit to provide an extended exercise area. 
         [0009]    The enclosure of the &#39;618 patent is constructed of multiple pieces that are difficult to keep track of when the enclosure is collapsed. To collapse the house unit, a pet owner removes the spreader bars and floor, and may also remove the support bows. When storing or transporting the enclosure, these separate pieces are cumbersome to carry and are easily lost. 
         [0010]    The design of the enclosure of the &#39;618 patent makes accessing the interior of the enclosure difficult. The openings of the enclosure are located on the end walls. Thus, when a pet owner places his or her pet inside the enclosure, he or she must move quickly to seal the opening before the pet runs back out. Also, when a pet owner wants to briefly open the enclosure with his or her pet inside, for example to play with the pet or insert or remove a food or water dish, the pet can easily exit the enclosure by running through the opening. 
         [0011]    Another example of a portable pet enclosure is manufactured by Cabana Crate Co. The enclosure comprises a nylon cover stretched about a frame that is substantially in the shape of a rectangular parallelepiped. The frame comprises aluminum tubing that is sewn into the cover. The tubes are sandwiched between layers of the cover material. The front, back and side walls of the cover are mesh, allowing air to circulate through the enclosure. A zipper connects the front wall to the side walls and floor. Unzipping the zipper enables a pet owner to access the interior of the enclosure. 
         [0012]    Because the Cabana enclosure opens along its front wall, it provides an easy escape route for the pet whenever the door is open. Also, because the frame tubes are integral with the cover, the cover is not removable from the frame. The cover is thus difficult to clean. It cannot be machine washed, because the frame cannot be placed in a washing machine together with the cover. Further, the area between the layers of cover material, in which the tubes reside, tends to trap dirt, pet hair, pet dander, etc. And if the pet has an “accident” inside the Cabana enclosure, this area traps the pet&#39;s waste and leaves the enclosure with an odor that is difficult to remove. 
         [0013]    Therefore, a portable pet enclosure from which pets cannot easily escape, that is not constructed of a multitude of pieces that are easy to lose, and that is easy to clean, would be of great benefit to pet owners. 
       SUMMARY OF THE INVENTION 
       [0014]    The preferred embodiments of the pet enclosure have several features, no single one of which is solely responsible for their desirable attributes. Without limiting the scope of this pet enclosure as expressed by the claims that follow, its more prominent features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description of the Preferred Embodiments,” one will understand how the features of the preferred embodiments provide advantages, which include integration of parts into a one-piece frame, easy transportability, easy washability, and easy access to the enclosure interior without enabling a pet&#39;s escape. 
         [0015]    A preferred embodiment of the present pet enclosure comprises a rigid support frame and a cover. The frame is constructed of a rigid floor, first and second rigid end trusses, and at least one jointed support member extending between the end trusses. 
         [0016]    Another preferred embodiment of the present pet enclosure comprises a support frame for a pet enclosure. The support frame comprises a floor member, a first end truss, a second end truss and at least one support member. The trusses are each constructed of at least one rigid member. The first and second end trusses are preferably hingedly connected to the floor truss. The at least one support member has a first end and a second end. The first end is hingedly connected to the first end truss, and the second end is hingedly connected to the second end truss. 
         [0017]    Another preferred embodiment of the present pet enclosure comprises a joint for releasably connecting a first member and a second member. The joint comprises a first connector and a second connector. The first connector is secured to an end of the first member, and the second connector is secured to an end of the second member. Preferably, an elasticized member extends between the ends of the first and second members. A locking sleeve is slidable on the members between a first position in which the sleeve is adjacent a junction of the ends of the first and second members, and a second position in which the sleeve covers the junction. 
         [0018]    Another preferred embodiment of the present pet enclosure comprises a rigid frame for a pet enclosure. The frame comprises a bottom truss, end trusses hingedly secured to opposite ends of the bottom truss, and at least one jointed support tube extending between the end trusses. 
         [0019]    Another preferred embodiment of the present pet enclosure comprises a method of folding a pet enclosure, wherein the pet enclosure comprises a jointed frame and a cover. The method comprises the steps of bending a jointed frame support member, folding a first frame end truss toward a frame floor member, folding a second frame end truss toward the floor member, and securing a first portion of the cover to a second portion of the cover, thereby resisting unfolding of the enclosure. 
         [0020]    Another preferred embodiment of the present pet enclosure comprises a rigid support frame and a cover. The frame is constructed of a rigid roof truss, first and second rigid end trusses, and at least one jointed support member extending between the end trusses. 
         [0021]    Any of the above embodiments may further comprise a fabric cover. The cover may be stretchable over the frame, or be supported externally by the frame. The cover is preferably completely removable from the frame so that it is easily machine washed. 
         [0022]    Another preferred embodiment of the present pet enclosure comprises a support frame for a pet enclosure. The support frame comprises a floor member defining a floor plane. The floor member includes at least a first pair of lugs that extend away from the floor plane and define a first pivot axis that is spaced from the floor plane. The floor member further includes at least a second pair of lugs that extend away from the floor plane and define a second pivot axis that is spaced from the floor plane. A first truss is pivotably connected to the first pair of lugs at the first pivot axis, and a second truss is pivotably connected to the second pair of lugs at the second pivot axis. The second pivot axis is spaced from the floor plane a greater distance than the first pivot axis. 
         [0023]    Another preferred embodiment of the present pet enclosure comprises a support frame for a pet enclosure. The support frame comprises a floor member, a first truss pivotably connected to the floor member at or near a first end thereof, and a second truss pivotably connected to the floor member at or near a second end thereof. The support frame further comprises at least one support member having a first end and a second end, the first end being pivotably connected to the first truss and the second end being pivotably connected to the second truss. The at least one support member comprises a first section and a second section, the first and second sections being separate pieces that are connectable to one another at a free end of each. The first section and the second section are of unequal lengths. 
         [0024]    Another preferred embodiment of the present pet enclosure comprises a support frame for a pet enclosure. The support frame comprises a floor member, a first truss pivotably connected to the floor member at or near a first end thereof, and a second truss pivotably connected to the floor member at or near a second end thereof. The support frame further comprises at least one support member having a first end and a second end, the first end being pivotably connected to the first truss and the second end being pivotably connected to the second truss. A locking sleeve is slidable on the at least one support member between a first position and a second position. The at least one support member comprises a first section and a second section, the first and second sections being separate pieces that are connectable to one another at a free end of each. When the locking sleeve occupies the first position the free ends of the first section and the second section may be separated from one another, and when the locking sleeve occupies the second position the free ends of the first and second sections may not be separated from one another. 
         [0025]    Another preferred embodiment of the present pet enclosure comprises a support frame for a pet enclosure. The support frame comprises a floor member, a first truss pivotably connected to the floor member at or near a first end thereof, and a second truss pivotably connected to the floor member at or near a second end thereof. The support frame further comprises at least one support member having a first end and a second end, the first end being pivotably connected to the first truss and the second end being pivotably connected to the second truss. A locking sleeve including a first through-hole and a second through-hole is slidable on the at least one support member between a first position and a second position. The support frame further comprises a push-button mechanism associated with the locking sleeve. The push-button mechanism cooperates with the first through-hole and the second through-hole to releasably lock the locking sleeve in the first position and the second position, respectively. 
         [0026]    Another preferred embodiment of the present pet enclosure comprises a cover and a support frame. The cover comprises a bottom panel, a top panel opposite the bottom panel, and a plurality of side panels extending between the bottom panel and the top panel to define an interior space of the cover. An aperture is defined in at least one of the top panel and one of the plurality of side panels for accessing the interior space. The support frame is pivotable between a collapsed configuration and an upright configuration and is insertable into the interior space of the cover through the aperture in the collapsed configuration of the support frame. The support frame is also pivotable from the collapsed configuration to the upright configuration while disposed within the interior space of the cover. 
         [0027]    A preferred embodiment of a cover for a pet enclosure having a support frame that is pivotable between a collapsed configuration and an upright configuration comprises a bottom panel, a top panel opposite the bottom panel, and at least one side panel extending between the bottom panel and the top panel. The bottom panel, the top panel, and the at least one side panel collectively define an interior space of the cover. The top panel comprises an aperture and a closure for selectively covering and uncovering the aperture to provide access to the interior space through the aperture. The support frame can be inserted into the interior space in the collapsed configuration and pivoted between the collapsed configuration and the upright configuration while being disposed within the interior space. 
         [0028]    A preferred method of folding an embodiment of the present pet enclosure that includes a cover and a support frame is also provided. The cover has a plurality of panels defining an interior space and at least one aperture providing access to the interior space, and the support frame is pivotable between a collapsed configuration and an upright configuration. The method comprises inserting the support frame through the aperture in the cover and into the interior space while the support frame is in the collapsed configuration. The method further comprises folding the cover atop of the collapsed support frame such that the cover is configured to be at least one of transported and stored with the collapsed support frame being disposed within the interior space. 
         [0029]    Other objects and features will be in part apparent and in part pointed out hereinafter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    The preferred embodiments of the pet enclosure, illustrating its features, will now be discussed in detail. These embodiments depict the novel and non-obvious pet enclosure shown in the accompanying drawings, which are for illustrative purposes only. These drawings include the following figures, in which like numerals indicate like parts: 
           [0031]      FIG. 1  is a front perspective view of a preferred embodiment of the present pet enclosure; 
           [0032]      FIG. 2  is a rear perspective view of the pet enclosure of  FIG. 1 ; 
           [0033]      FIG. 3  is a side elevation view of a preferred embodiment of a frame for the pet enclosure of  FIG. 1 , illustrating the locking sleeves in the locked position; 
           [0034]      FIG. 4  is a side elevation view of the frame of  FIG. 3 , illustrating the locking sleeves in the unlocked position; 
           [0035]      FIG. 5  is a side elevation view of the frame of  FIG. 3 , illustrating the locking sleeves in the unlocked position and the support tubes bent; 
           [0036]      FIG. 6  is a side elevation view of the frame of  FIG. 3 , illustrating a first end truss in a folded position; 
           [0037]      FIG. 7  is a side elevation view of the frame of  FIG. 3 , illustrating the frame in the folded position; 
           [0038]      FIG. 8  is an end elevation view of the frame of  FIG. 3 ; 
           [0039]      FIG. 9  is a cross-sectional end view of the frame of  FIG. 3 , taken through the line  9 - 9 ; 
           [0040]      FIG. 10  is a detail view of the frame of  FIG. 3 , illustrating the joint and locking sleeve in the locked position; 
           [0041]      FIG. 11  is a detail view of the frame of  FIG. 3 , illustrating the joint and locking sleeve in the unlocked position; 
           [0042]      FIG. 12  is a detail view of the frame of  FIG. 3 , illustrating the locking sleeve in the unlocked position and the joint in the bent position; 
           [0043]      FIG. 13  is a cross-sectional detail view of the frame of  FIG. 3 , illustrating the joint and locking sleeve in the locked position; 
           [0044]      FIG. 14  is a cross-sectional detail view of the frame of  FIG. 3 , illustrating the joint and locking sleeve in the unlocked position; 
           [0045]      FIG. 15  is a detail view of the frame of  FIG. 3 , illustrating a hinge joining the bottom truss and an end truss; 
           [0046]      FIG. 16  is a detail view of the frame of  FIG. 3 , illustrating a hinge joining a support tube and an end truss; 
           [0047]      FIG. 17  is a perspective view of the frame of  FIG. 3 ; 
           [0048]      FIG. 18  is a side elevation view of the pet enclosure of  FIG. 1 , illustrating the pet enclosure in a folded configuration; and 
           [0049]      FIG. 19  is a front perspective view of another preferred embodiment of the present pet enclosure, illustrating an external frame. 
       
    
    
       [0050]    Corresponding reference characters indicate corresponding parts throughout the drawings. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0051]    The present pet enclosure  20 , pictured in  FIGS. 1 ,  2  and  18 , comprises a fabric cover  22  supported by a rigid frame  24 . In the illustrated embodiment, the enclosure  20  is shaped generally as a six-sided rectangular box, having a top panel  26 , a floor panel  28 , a front panel  30 , a rear panel  32 , and two side panels  34 . Those of skill in the art will appreciate that the enclosure  20  could have any number of sides, and could be a variety of other shapes and sizes. The enclosure  20  is preferably available in a variety of sizes to accommodate pets of different sizes. 
         [0052]    The cover  22  is preferably constructed of a lightweight but durable fabric that is resistant to being torn by pet teeth or claws, and can withstand repeated machine washing and drying without wearing out or shrinking. A preferred material is nylon. Those of skill in the art will appreciate that other materials could be used, such as canvas or plastic. Corners of the enclosure  20  preferably include reinforcing patches  36 . Each patch  36  is substantially triangular, with each corner of each triangle residing along a border edge  38  of two contiguous panels  26 ,  28 ,  30 ,  32 ,  34 . The patches  36  are preferably constructed of a durable material, such as nylon or leather. The patches  36  not only reinforce the cover  22  and increase its life span, but they also provide a cushion so that the corners of the enclosure  20  are less likely to damage objects that they strike. 
         [0053]    The cover  22  preferably includes substantially non-breathable fabric portions  40  and breathable mesh portions  42  that enable air to circulate through the enclosure  20 . In the illustrated embodiment, the floor panel  28  is constructed of only non-breathable fabric  40 , while the remaining panels  26 ,  30 ,  32 ,  34  are constructed of a combination of non-breathable fabric  40  and breathable mesh  42 . Each of these panels  26 ,  30 ,  32 ,  34  includes a central mesh portion  42  surrounded by a fabric border  40 . The side panels  34  may also include a fabric portion  40  running diagonally through the central mesh portion  42 . Those of skill in the art will appreciate that the panels  26 ,  28 ,  30 ,  32 ,  34  could comprise a variety of other combinations of fabric and mesh portions. For example, some panels could comprise entirely mesh, or entirely fabric, or the sizes and/or shapes of the mesh and fabric portions could be different. 
         [0054]    Opaque shades (not shown) could be provided to selectively cover the mesh portions  42  of each panel. For example, flaps could be sewn or otherwise secured to one or more of the panels  26 ,  30 ,  32 ,  34 . When flat, the flaps could cover the mesh portions  42 , and be secured in place with zippers, snaps, or the like. In this configuration, the flaps would provide privacy to a pet inside the enclosure  20 . The flaps would also prevent sunlight from entering the enclosure  20 , which would keep the pet cooler on hot sunny days. Likewise, the flaps would prevent wind and rain from entering the enclosure  20 , which would keep the pet warmer and drier on cold rainy days. When rolled up or removed, the flaps could be secured adjacent the mesh portions  42  with straps or the like. In this configuration, the flaps would enable air and sunlight to enter the enclosure  20 . 
         [0055]    The enclosure  20  may also include a waterproof canopy (not shown). The canopy may comprise a canvas or nylon sheet large enough to stretch over the enclosure  20 . The enclosure  20  may support the canopy directly, or the canopy may be supported with substantially vertical poles, guy wires and stakes. The canopy may be integral with the enclosure  20 , or an independent structure. The canopy provides shelter from rainstorms, keeping the interior of the enclosure  20  dry so that a pet can be left outdoors inside the enclosure  20  even on rainy days. 
         [0056]    A first edge  44  of the mesh portion  42  of the top panel  26  is preferably stitched to the fabric portion  40 . The remaining three edges of the mesh portion  42  are releasably secured to the fabric portion  40  with a zipper  46 , which is actuated by one or more zipper pull tabs  47 . The top panel  26  thus includes a recloseable top opening  48  that provides access to the interior of the enclosure  20 . A pet owner can easily place a pet into, or remove a pet from, the enclosure  20  through the top opening  48 . Because the top opening  48  is located in the top panel  26 , a pet within the enclosure  20  cannot easily escape from the enclosure  20  when the top opening  48  is unzipped. Thus, when the pet is within the enclosure  20 , the owner can add or remove items through the top opening  48 , such as food and water dishes, toys or blankets, without having to guard against the pet escaping. The owner can also interact with the pet through the top opening  48 . For example, the owner can pet the animal, brush its fur, etc. 
         [0057]    The top panel  26  of the cover  22  preferably includes a retaining strap  50  secured near the first edge  44  of the mesh portion  42  forming the top opening  48 . An end of the strap  50  preferably includes securing means (not shown), such as a button, snap or hook-and-loop fastener. When the mesh portion  42  is unzipped and rolled up, as shown in  FIG. 1 , the strap  50  is securable around the rolled up mesh portion  42 . The securing means on the strap  50  is attachable to a mating securing means  106  that is preferably attached to an inside surface of the open mesh portion  42 , or to an inside surface of the cover  22 . 
         [0058]    The cover  22  also preferably includes a second recloseable opening  52  in the front panel  30 . Like the top opening  48 , the front opening  52  comprises a mesh portion  42  that is stitched along a first edge  54  to a fabric border portion  40 . The remaining three edges are releasably secureable to the fabric border  40  with a zipper  46 , which is also actuated by one or more zipper pull tabs  47 . The front opening  52  enables a pet owner to allow his or her pet to enter and exit the enclosure  20  without assistance from the owner. For example, if the pet is heavy or otherwise difficult to pick up and place in the enclosure  20  through the top opening  48 , the owner can open the front opening  52  and urge the pet into or out of the enclosure  20 . 
         [0059]    The cover preferably includes a security snap clip  116  ( FIG. 1 ). The clip  116  is insertable through holes in the zipper pull tabs  47 , and locks the front opening  52 . The clip  116  is anchored to the cover  22 . If both zipper pull tabs  47  are located near the clip  116 , and the clip  116  is inserted into the pull tab  47  that would be used to unzip the front opening  52 , then that zipper  46  is immobilized and the front opening  52  cannot be opened. The pet inside the enclosure thus cannot unzip the front opening  52  in order to escape from the enclosure  20 . A second clip  116  may be provided adjacent the top opening  48 . 
         [0060]    Rather than being anchored to the cover  22 , the clip could be independent of the cover  22 . If the independent clip  116  were inserted through both zipper pull tabs  47 , the top opening  48  or front opening  52  could not be opened, because as one zipper pull tab  47  moves to open the enclosure  20 , the other zipper pull tab  47  follows right behind to reclose the enclosure  20 . Those of skill in the art will appreciate that the enclosure need not include the security snap clip  116 . 
         [0061]    In the illustrated embodiment, the exterior surface of the rear panel  32  ( FIG. 2 ) of the cover  22  includes a pocket  55 , a zippered pocket  56  and a mesh pouch  58 . The pockets  55 ,  56  and pouch  58  are useful for holding pet accessories, such as food, treats, toys and grooming tools. Those of skill in the art will appreciate that the pockets  55 ,  56  and pouch  58  could be located anywhere on the cover  22 , including the interior surface of the cover  22 . Those of skill in the art will further appreciate that the enclosure  20  need not include any pockets or pouches. The cover  22  may also include receptacles (not shown) for containing food and/or water. The receptacles may be located on either the interior or the exterior of the cover  22 , and may comprise, for example, rigid or semi-rigid plastic bowls. Alternatively, the cover  22  may include soft pockets for holding rigid or semi-rigid plastic bowls. 
         [0062]    The cover preferably includes tabs  118  ( FIGS. 1 and 2 ) for accepting stakes (not shown). The tabs  118  are attached to the cover floor panel  28 , or adjacent the floor panel  28 . The tabs  118  each include a hole  120 , through which a stake can be driven to firmly secure the enclosure  20  to the ground. Each hole  120  is preferably reinforced with a grommet  121 , which is preferably constructed of any sturdy material such as metal or high-impact plastic. Those of skill in the art will appreciate that the enclosure need not include the tabs  118 . 
         [0063]    A rigid frame  24  ( FIGS. 3-17 ) supports the cover  22 . In the illustrated embodiment, the frame  24  is internal to the cover  22 . Those of skill in the art will appreciate that the frame  24  may be external to the cover  22 , as illustrated in  FIG. 19 . The frame  24  comprises a substantially rectangular floor truss  60 , two substantially U-shaped end trusses  62 , and jointed support tubes  64  extending between upper edges of the end trusses  62  ( FIG. 17 ). 
         [0064]    The word truss, as used herein, is defined as a rigid frame comprised of at least two interconnected members. For example, a truss includes four bars welded to one another to form a rectangular frame. The definition of truss, as used herein, is not exclusive of any manner of attaching the truss members together. The members may be, for example, welded, adhered, riveted, screwed, bolted, nailed, etc, to one another. The members may even be formed integrally with one another. For example, four tubes that are formed as a single piece four-sided frame comprise a truss. The definition of truss, as used herein, is also not exclusive of any material. The truss members may be, for example, metal, plastic, composite, wood, ceramic, etc. 
         [0065]    The floor truss  60  and the end trusses  62  are each constructed of rigid bars or tubes  66  ( FIG. 17 ). For ease of reference, the tubes  66  will be referred to herein as tubes, even though they could comprise solid bars, as those of skill in the art will appreciate. 
         [0066]    The bars or tubes  66  may be made of any suitable rigid material that is preferably lightweight. Preferred materials include, without limitation, metals such as steel or aluminum, plastics, and composites. The illustrated tubes  66  are of circular cross-section. However, those of skill in the art will appreciate that the tubes could be of any cross-section, such as square or hexagonal. The floor truss  60  may comprise a single tube  66  that is bent at right angles in four places and the ends of the tube  66  connected to one another. Alternatively, the floor truss  60  may comprise four separate tubes  66  connected to one another at their ends to form four corners. Preferably, corners of the trusses  60 ,  62  are somewhat rounded to reduce the likelihood of injury to someone bumping into the frame  24 . 
         [0067]    Those of skill in the art will appreciate that the frame  24  may be configured differently. For example, if the frame were inverted, the floor truss  60  could be used to support a roof of the enclosure  20 . The jointed support tubes  64  would then extend between lower edges of the end trusses  62 . The floor truss  60  could also include a floor panel (not shown). For example, a flat rectangular panel could be secured to lower, upper or inner surfaces of the tubes  66  comprising the floor truss  60 . The panel could, for example, be made of metal, fiberglass or a composite material, and could be secured to the floor truss  60  by welding or adhesive. Alternatively, the floor truss  60  could be eliminated, and the end trusses  62  could be secured directly to the floor panel. 
         [0068]    Four lugs  68  ( FIGS. 3 ,  4 ,  15  and  16 ) are preferably secured to the floor truss  60 , one lug  68  near each corner of the floor truss  60 . Each lug  68  comprises a substantially rectangular plate that is secured to the floor truss  60  such that a plane defined by each lug  68  is perpendicular to a plane defined by the floor truss  60 . Each lug  68  includes a through-hole (not shown) for receiving a hinge pin  67  ( FIGS. 15 and 16 ). 
         [0069]    The end trusses  62  are pivotably attached to the lugs  68 . Each of the end trusses  62  is preferably three-sided and substantially U-shaped. Like the floor truss  60 , the end trusses  62  are constructed of rigid bars or tubes  66 . The bars or tubes  66  may be made of any suitable rigid material that is preferably lightweight. Preferred materials include, without limitation, metals such as steel or aluminum, plastics, and composites. The end trusses  62  may comprise a single tube  66  that is bent in two places. Alternatively, the end trusses  62  may comprise three separate tubes  66  connected to one another at their ends to form a U. 
         [0070]    A hinge portion  70  ( FIGS. 15 and 16 ) is inserted within the ends of the tube or tubes  66  forming the open end of the U in each end truss  62 . Each hinge portion  70  is substantially cylindrical. A first end of the hinge portion  70  resides within the end of the tube  62  in a friction fit. The hinge portions  70  may also be attached to the end trusses  62  by alternate means. For example, if the end trusses  62  comprise solid bars, rather than hollow tubes, the hinge portions  70  may be glued, welded or otherwise attached to the bars. Even when the hinge portions  70  are inserted into tubular panels, the hinge portions  70  may also be secured by gluing, welding or the like for a stronger hold. 
         [0071]    A length of each hinge portion  70  extends from the end of the tube  66 . This exposed portion  72  includes a longitudinal slit  74  ( FIG. 16 ) that extends through the entire diameter of the hinge portion  70 . A transverse through-hole (not shown) extends through the exposed portion  72  and intersects the space defined by the slit  74 . The slit  74  is configured to accept a lug  68 , such that the through-hole in the hinge-portion  70  aligns with the through-hole in the lug  68 . A hinge pin  67  inserted through both through-holes pivotably secures the hinge portion  70  to the lug  68 . The two hinge portions  70  at either open end of the end trusses  62 , respectively, thus pivotably attach the end trusses  62  to the lugs  68  on the floor truss  60 . 
         [0072]    Each support tube  64  comprises a long portion  76  and a short portion  78  ( FIGS. 3 and 4 ). A first end  80  ( FIG. 3 ) of each portion  76 ,  78  is pivotably attached to an upper portion  82  of an end truss  62  in a similar manner as the end trusses  62  are pivotably attached to the floor truss  60 . Second ends  84  ( FIG. 4 ) of each portion  76 ,  78  are releasably connectable to each other via a joint  86  ( FIGS. 4 ,  13  and  14 ). Each joint  86  comprises a female connector  88  having a substantially cylindrical exterior and a substantially cylindrical socket  90  at a first end. Each joint  86  also comprises a male connector  92  having a substantially cylindrical exterior and a substantially cylindrical plug  94  at a first end. An outer diameter of the plug  94  is preferably roughly equal to an inner diameter of the socket  90 . The plug  94  is thus snugly slidable within the socket  90 . 
         [0073]    The exterior of the female connector  88  fits snugly within the second end  84  of the support tube long portion  76 . The exterior of the male connector  92  fits snugly within the second end  84  of the support tube short portion  78 . The long portion  76  and short portion  78  are thus connectable to one another by insertion of the plug  94  into the socket  90 . In this configuration, each support tube  64  becomes a one-piece bar that is rigid in compression and maintains the end trusses  62  in their upright positions, as shown in  FIGS. 3 and 4 . 
         [0074]    A substantially cylindrical passage  96  extends through both the female and male connectors  88 ,  92 . An elastic cord  98  ( FIGS. 12 ,  13  and  14 ) preferably extends through each passage  96  and is secured at either end to the female and male connectors  88 ,  92 , or in the portions  76 ,  78 . Tension in the elastic cord  98  urges the female and male connectors  88 ,  92  toward one another. Thus, although each support tube  64  comprises two pieces  76 ,  78 , the elastic cords  98  assist in aligning and securing the two pieces together. Those of skill in the art will appreciate that the elastic cords  98  need not be provided. However, the elastic cords  98  facilitate quick setup of the enclosure  20 , as described below. The elastic cords  98  also make the frame  24  more manageable by preventing the detached pieces  76 ,  78  from flopping around. 
         [0075]    Each support tube  64  preferably includes a substantially cylindrical locking sleeve  100  ( FIGS. 10-14  and  17 ). The sleeve  100  is slidable along the support tube  64  from a locked position ( FIGS. 10 ,  13  and  17 ) to an unlocked position ( FIGS. 11 ,  12  and  14 ). In the locked position, the sleeve  100  covers the joint  86  between the short and long portions  76 ,  78  of the support tube  64  and increases the overall rigidity of the support frame  24 . In the unlocked position, the sleeve  100  is slid away from the joint  86  such that the short and long portions  76 ,  78  are easily pulled apart from one another and the support tubes  64  bent as shown in  FIG. 5 , and in detail in  FIG. 12 . Preferably, a length of the cover  22  is substantially equal to a length of the support tubes  64 . Thus, when the cover  22  is stretched over the frame  24 , the cover  22  resists any tendency of the short and long portions  76 ,  78  to separate from one another. 
         [0076]    The sleeve  100  includes two through-holes  102  ( FIGS. 13 and 14 ), one near each end of the sleeve  100 . The holes  102  lie along a line that is parallel to a longitudinal axis of the sleeve  100 . Near the joint  86 , the long portion  76  of each support tube  64  includes a U-shaped, cantilevered leaf spring  104  with a button  106  near a free end. The button  106  protrudes through a hole  108  in a side wall of the support tube  64 . The button  106  is aligned with the line joining the two holes  102  on the sleeve  100 . Thus, when the sleeve  100  is in the locked position, the button  106  protrudes through one hole  102  in the sleeve  100 . As the sleeve  100  slides along the support tube  64  toward the unlocked position, it maintains the button  106  in a depressed position until it reaches the unlocked position, where the button  106  pops up into the other hole  102  in the sleeve  100 . The button  106  thus releasably locks the sleeve  100  in either the locked or unlocked position. 
         [0077]    The enclosure  20  is foldable into the configuration illustrated in  FIG. 18 . The front panel  30  is folded approximately ninety-degrees toward the floor panel  28  such that the two panels are substantially parallel. The rear panel  32  is also folded approximately ninety-degrees toward the floor panel  28 , such that it rests atop the front panel  30 , and is substantially parallel to both the floor panel  28  and the front panel  30 . In this configuration, the enclosure  20  comprises a compact flat panel that occupies a fraction of the space that the unfolded enclosure  20  of  FIGS. 1 and 2  occupies. The folded enclosure is thus easy to store and easy to transport. 
         [0078]    Preferably, the cover  22  includes closure clips  110  ( FIGS. 1 ,  2  and  18 ), which comprise releasably lockable male and female connectors. The clips  110  secure the enclosure  20  in the folded configuration as shown in  FIG. 18 . The enclosure  20  cover  22  may also include a side handle  112  ( FIG. 2 ) to enable easy carrying of the folded enclosure  20 . Alternatively, the enclosure  20  may include a bag (not shown) into which the folded enclosure  20  may be inserted for easy carrying or storage. Additional handles (not shown) may also be provided to facilitate carrying of the enclosure  20  when the enclosure  20  is in the unfolded configuration as in  FIG. 1 . The handles could be conveniently positioned along the upper edges of the cover  22  to enable a pet owner to pick up the enclosure  20 , perhaps with a pet inside, and carry it to a different location. The handles could alternatively be secured directly to the frame  24 , and could protrude through apertures (not shown) in the cover  22 , if the frame  24  is internal. 
         [0079]    The procedure for folding the enclosure  20  is illustrated in  FIGS. 3-7 . For clarity, the procedure is illustrated with the cover  22  removed from the frame  24 . However, most pet owners will likely prefer to fold the enclosure without first removing the cover  22 , because such removal is unnecessary for storage or transportation of the enclosure  20 . 
         [0080]    The pet owner first unzips the top opening  48  and removes the pet and other articles from the enclosure  20 . Next, the pet owner depresses the button  106  and slides both locking sleeves  100  from the locked position ( FIG. 3 ) to the unlocked position ( FIG. 4 ). The owner then pushes downward on the support tubes  64  at or near the joints  86  so that the support tubes  64  bend ( FIG. 5 ). Advantageously, the elastic cords  98  retain the portions  76 ,  78  of the support tubes  64  in close proximity. The elastic cords  98  thus guide the support tubes  64  to their desired orientations during folding so that the owner does not have to guide them with his or her hand. 
         [0081]    Next, the owner folds downward the end truss  62  that is connected to the short portions  78  of the support tubes  64  ( FIG. 6 ). In the illustrated embodiment, the first-folded end truss  62  corresponds to the front panel  30  ( FIGS. 1 ,  2  and  18 ). However, those of skill in the art will appreciate that the orientation of the cover  22  relative to the frame  24  may be reversed such that the end truss  62  corresponds to the rear panel  32 . In such an orientation, the owner would fold the rear panel  32  first. 
         [0082]    As the owner folds the first end truss  62 , the short portions  78  pivot about the lugs  68  toward the first end truss  62 . When a plane defined by the first end truss  62  is substantially parallel to the long portions  76 , the short portions  78  begin to pivot in the opposite direction. The short portions  78  continue to pivot in this direction until the plane defined by the first end truss  62  is substantially parallel to a plane defined by the floor truss  60 . In this configuration, shown in  FIG. 6 , the short portions  78  are substantially parallel to the plane defined by the first end truss  62  and extend away from the first end truss  62 . 
         [0083]    Tucking the cover  22  inside, the owner then folds downward the remaining end truss  62  so that it rests on top of the first-folded end truss  62  ( FIGS. 7 and 18 ). Preferably, the lugs  68  to which the second-folded end truss  62  are attached are somewhat longer than the lugs  68  to which the first-folded end truss  62  are attached. Thus, when the second panel is folded on top of the first, the panels  62  are able to occupy spaced parallel planes. The enclosure  20  is thus able to fold more compactly. To facilitate tighter nesting between the end trusses  62 , the end trusses  62  may have different widths. For example, the end truss  62  that is folded first may be narrower than the end truss  62  that is folded second. The parallel legs of the first-folded end truss  62  would then nest inside the parallel legs of the second-folded end truss  62 . 
         [0084]    Preferably, inside surfaces of the cover  22  that abut the frame  24  include straps  114  ( FIG. 2 ). The straps  114  include releasable securing means, such as snaps or hook-and-loop fastener. The straps  114  are wrapped around the tubes  66  of the end trusses  62  to more securely fasten the cover  22  to the frame  24 . Thus, as the owner folds the enclosure  20 , the cover  22  follows the motion of the end trusses  62 . Those of skill in the art will appreciate that the straps  114  need not be provided. 
         [0085]    If the cover  22  is external to the frame  24 , the cover  22  preferably includes straps  114  on its outside surfaces, as shown in  FIG. 19 . The straps  114  secure the cover  22  to the frame  24  so that the flexible cover  22  does not collapse under its own weight. When the enclosure  20  is folded, the straps  114  also allow the cover  22 , to follow the motion of the end trusses  62 . 
         [0086]    To secure the enclosure in the folded configuration shown in  FIG. 18 , the owner secures the mating ends of the closure clips  110  together. The owner can thus grasp the handle  112  and carry the enclosure  20  in an upright plane without gravity unfolding the enclosure  20 . 
         [0087]    The procedure for unfolding the enclosure  20  comprises, in reverse order, the steps from the folding procedure just described. Again, the elastic cords  98  advantageously guide the support tube portions  76 ,  78  to the aligned position of  FIG. 5 . The owner thus need not guide them himself or herself, which would add complexity to the unfolding procedure. 
         [0088]    Advantageously, the frame  24  of the present enclosure  20  is made up of jointed pieces that are all attached to one another, even when the enclosure  20  is completely folded. The separate portions  76 ,  78  of the support tubes  64  are secured to one another with the elastic cord  98 . The frame  24  is thus manipulable as one piece, and is portable as one piece. There are no extra components to keep track of. 
         [0089]    As those of skill in the art will appreciate, the elastic cords  98  need not be provided. In an embodiment of the enclosure  20  that does not include the elastic cords  98 , folding would proceed substantially as described above. However, rather than bending the support tubes  64  at or near the joints  86 , the owner would separate the pieces  76 ,  78  and allow each one to pivot to an orientation wherein each hung parallel to the end trusses  62 . The owner would then fold the end trusses  62  as described above, securing each piece  76 ,  78  under its respective end truss  62 . In addition, each interconnected member of a truss may be secured to the other interconnected member(s) through the use of other hinged arrangements or securement devices. For example, the members may be welded to one another or formed of one integral piece. 
         [0090]    The cover  22  of the present enclosure  20  is completely removable from the support frame  24 . To remove the cover  22 , the owner first detaches the cover from the frame  24  by reaching through one of the openings  48 ,  52  and unfastening the straps  114  (if straps  114  are provided) from the tubes  66 . The owner then folds the frame  24  by following the procedure described above. However, the owner folds the frame  24  independently of the cover  22 . The owner can then easily remove the compact folded frame  24  from the cover  22  by passing it through one of the openings  48 ,  52 . 
         [0091]    The cover  22  is thus easily washable, because it can be machine washed when separated from the frame  24 . Also, an owner may easily replace a worn-out cover  22  without having to purchase an entire enclosure  20 . An owner may also purchase additional covers  22  in different colors. The owner may then change the cover  22  as needed to, for example, match a room&#39;s decor. 
       SCOPE OF THE INVENTION 
       [0092]    The above presents a description of the best mode contemplated for carrying out the present pet enclosure, and of the manner and process of making and using it, in such full, clear, concise and exact terms as to enable any person skilled in the art to which it pertains to make and use this pet enclosure. This pet enclosure is, however, susceptible to modifications and alternate constructions from that discussed above that are fully equivalent. Consequently, this pet enclosure is not limited to the particular embodiments disclosed. On the contrary, this pet enclosure covers all modifications and alternate constructions coming within the spirit and scope of the pet enclosure as generally expressed by the following claims, which particularly point out and distinctly claim the subject matter of the pet enclosure.

Summary:
A pet enclosure includes a cover and a support frame. The cover includes a bottom panel, a top panel opposite the bottom panel, and a plurality of side panels extending between the bottom panel and the top panel to define an interior space of the cover. An aperture is defined in at least one of the top panel and one of the plurality of side panels for accessing the interior space. The support frame is pivotable between a collapsed configuration and an upright configuration and is insertable into the interior space of the cover through the aperture in the collapsed configuration of the support frame. The support frame is also pivotable from the collapsed configuration to the upright configuration while disposed within the interior space of the cover.