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This application claims the benefit of priority based on Provisional Application No. 60/652,547 entitled “A Pet Door Assembly,” filed Feb. 14, 2005. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to a pet door assembly. More particularly, this invention relates to a pet door assembly, to a kit for a pet door assembly and to an accessory for a pet door assembly. This invention finds particular application to screen doors, but would have other applications as well. 
     BACKGROUND OF THE INVENTION 
     Pet door assemblies are well known. They usually include a frame mounted in an existing closure and a closure member or flap that can be urged open by the pet. The closure member is mounted on the frame to be displaced, either by gravity or a spring, back into a closed position, once the pet has passed through an opening defined by the frame. 
     In U.S. Pat. No. 3,985,174, published Oct. 12, 1976, there is described a pet door that is installed in a window screen or screen door. In this patent, the frame of the pet door is fastened to a facing surface of a frame of the window screen or screen door. A problem with this arrangement is that the frame has to suit the dimensions of the window screen or screen door. In particular, a distance from the screen itself to the associated facing surface is critical. Furthermore, in the case of a sliding screen door, the frame could interfere with relatively sliding door members. 
     In U.S. Pat. No. 4,334,573, published Jun. 15, 1982, there is described a pet access door kit. This kit is essentially a frame that is fastened to a facing surface of the frame of a screen door. Screen material bounded by the frame is cut and a weight is fastened to the screen material so that the screen material defines a flap. This arrangement also has the problems of interference and limited adjustability described above. 
     In U.S. Pat. No. 5,701,813, published Dec. 30, 1997, there is described a pet door also for a screen door. As with the previous patents, this patent displays the same problems with a frame or mounting bracket being fastened to a facing surface of a frame of the screen door. 
     In some cases, for example in U.S. Pat. No. 5,535,804 published Jul. 16, 1996, the frame of the pet door is mounted directly on to the screen, without engagement with a frame of the window or screen door. Applicant submits that such an arrangement will not be able to withstand the rigors of day-to-day use, especially with energetic, larger dogs. 
     The Applicant is the proprietor of Australian patent no. 759436, the contents of which are hereby specifically incorporated by reference. This patent covers a pet door that is mountable in a security screen door commonly found in Australia. However, Applicant has found that such security screen doors are not generally found in the United States. Rather, a simple frame and screen arrangement appears to be predominant in the United States, particularly in the warmer areas. Applicant has developed the pet door of this Australian patent further in conceiving the present invention, so that the pet door can be used with conventional screen doors. 
     SUMMARY OF THE INVENTION 
     According to a first aspect of the invention, there is provided a pet door assembly which comprises 
     a support structure that defines an access opening through which a pet can pass; 
     a connecting arrangement on the support structure to permit the support structure to be connected to at least one mounting member fastenable to an inwardly facing surface of a closure frame; and 
     a self-closing door that is mounted on the support structure to be displaceable between a closed position in which the door closes the access opening and an open position. 
     According to a second aspect of the invention, there is provided a kit for a pet door assembly, the kit comprising 
     at least one mounting member that is fastenable to an inwardly facing surface of a closure frame; 
     a support structure that is fastenable to the, or each, mounting member, the support structure defining an access opening through which a pet can pass; and 
     a self-closing door that is mounted on the support structure to be displaceable between a closed position in which the door closes the access opening and an open position. 
     The kit may include one mounting member. The mounting member may be a connector having a first elongate portion and a second elongate portion oriented at right angles to the first portion. The connector may define openings to permit the connector to be fastened to said inwardly facing surface with fasteners received through the openings. Thus, the connector may be fastenable to a corner portion of the closure frame. 
     Instead of a single connector, the assembly may include two connectors. In this case each connector may be fastenable to respective frame members that define the corner portion of the closure frame. 
     The support structure may include a framework that defines the access opening. The framework may thus be connectable to the connector. 
     The framework may define a peripheral channel that opens outwardly. The connector may be at least partially receivable in the channel. Connecting formations may extend from the connector to engage complementary connecting formations in the channel. 
     The connecting formations may be interlocking ribs defined by the connector and by the framework in the peripheral channel. At least the connector may be of a resiliently flexible material to allow the framework to be urged on to the connector such that the ribs engage each other in an interlocking manner. 
     The invention finds particular, but not exclusive, application to screen doors. As is known, the closure frame of such doors is spanned by an insect screen. 
     Furthermore, the closure frame defines an inwardly facing surface adjacent the insect screen. In use, the connector is fastened to this surface. 
     It will be appreciated that the insect screen then extends over the access opening. The screen material that spans the access opening is cut away. An attaching arrangement may be positioned on an interior side of the framework to permit an inner peripheral portion of the screen material to be fastened to the interior side of the framework. 
     The self-closing door may include a flap member that is pivotally mounted in the framework. 
     According to a third aspect of the invention, there is described an accessory for a pet door assembly of the type described above, the accessory comprising at least one mounting member that is fastenable to a corresponding inwardly facing surface of a closure frame, a support structure of a pet door assembly being fastenable to the, or each, mounting member, the support structure defining an access opening through which a pet can pass. 
     According to a fourth aspect of the invention, there is provided an enclosure assembly which includes 
     a number of wall members that are connectable to each other to define an enclosure; 
     a support structure that defines an access opening through which a pet can pass, mounted in one of the wall members so that the access opening opens into the enclosure; and 
     a self-closing door that is mounted on the support structure to be displaceable between a closed position in which the door closes the access opening and an open position. 
     The invention is now described, by way of example, with reference to the accompanying drawings. The following description is intended to describe the best manner of performing the invention known to the Applicant at the time of filing the application. As such, the following description is not intended to limit the broad scope of the preceding paragraphs. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a three-dimensional view of a pet door assembly, in accordance with the invention. 
         FIG. 2  shows a detailed view of part of the pet door assembly and an accessory, in accordance with the invention, for the pet door assembly. 
         FIG. 3  shows a partly cut away view of the pet door assembly. 
         FIG. 4  shows a cross-sectioned view taken through section IV-IV in  FIG. 3  of part of a frame of the pet door assembly. 
         FIG. 5  shows a three dimensional view of the accessory for the pet door assembly. 
         FIG. 6  shows part of a wall of a structural enclosure, in accordance with the invention, incorporating the pet door assembly. 
         FIG. 7  shows a schematic view of part of the frame of the pet door assembly being mounted to the accessory of  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In  FIG. 1 , reference numeral  10  generally indicates a pet door assembly, in accordance with the invention. 
     The assembly  10  includes a support structure in the form of a frame  12 . A flap  14  is mounted in the frame  12 . The frame  12  has a generally rectangular shape with four side portions  22  defining an opening  24  through which a pet can pass. The flap  14 , is pivotally mounted in the frame  19  to be pivotal between a closed position in which the flap  14  closes the opening  24  and an open position. 
     In  FIG. 3 , there is shown a cut away view of the assembly  10  and in  FIG. 4  there is shown a cross-sectional view of the frame  12  and flap  14  taken though a pivot axis of the flap  14 . As can be seen, the frame  12  includes an interior frame member  16  and an exterior frame member  18  that are fastened together with fasteners, one of which is indicated at  20 . An outer portion  30  of each frame member  16 ,  18  defines corresponding, longitudinally extending ribs  26  so that, when the frame members  16 ,  18  are fastened together, the ribs  26  extend into a channel  28  defined by the frame members  16 ,  18 . 
     Both the frame members  16 ,  18  define a pair of corresponding opposed pivot formations  32  that retain respective pivot rods  34  of the flap  14  between respective corresponding pivot formations  32 . 
     The interior frame member  16  has a channel portion  36  that extends about the frame  12  between the outer portion  30  and an inner portion  44  of the interior frame member  16 . A floor  38  of the channel portion  36  bears against a portion  40  of the exterior frame member  18  interposed between the outer portion  30  and an inner portion  46  of the exterior frame member  18 . The channel portion  36  is dimensioned to provide a suitable spacing between the corresponding outer portions  30 , thereby to define a width of the channel  28 . 
     The exterior member  18  defines a locating formation  42  to locate the channel portion  40  and thus the interior member  16  correctly relative to the exterior member  18 . 
     In use, during installation, the frame  12  is fastened to a frame  48  of a screen door (see  FIG. 1 ). An insect screen  50  is then cut along a line slightly inward of the channel portion  36 . An elastomeric bead  52  is urged into the channel portion  36  to trap and retain an inner edge portion  54  of the screen  50  in the channel portion  36  and against the interior member  16 . 
     In  FIGS. 2, 5 and 7 , reference numeral  60  generally indicates an accessory, in accordance with the invention, for use with the pet door assembly  10 . 
     The accessory  60  includes a pair of mounting members or connectors  62 . Each connector  62  is an elongate extrusion of a plastics material. Each connector  62  has openings  64  to permit the connector  62  to be fastened to an inwardly facing surface  78  of a respective element  66  of the frame  48  of the screen door. 
     Each connector  62  defines a series of longitudinally extending ridges  70  that correspond with the ribs  26  of the frame members  16 ,  18 . The ridges  70  and the ribs  26  are such that the connectors  62  can be clipped into respective channels  28  to retain the connectors  62  in the channels  28 . In  FIG. 7 , an arrow  102  indicates a direction in which the assembly  10  is urged to clip the assembly  10  to one of the connectors  62 . 
     The connectors  62  are mounted on respective corner elements  66  of the frame  48  (see  FIG. 2 ). One of the connectors  62 . 1  has a spigot  72  that extends from an end of the connector  62 . 1 . The other connector  62 . 2  defines a recess  74  in which the spigot  72  nests to retain the connectors  62  at right angles to each other. 
     In use, the connectors  62  are fastened to respective elements  66  at a corner  76 , with the spigot  72  received in the recess  74 . The frame  12  is then clipped to the connectors  62 . The screen  50  is cut and secured as described above. 
     Corresponding magnetic elements  80  are positioned in a lower edge of the flap  14  and an adjacent portion of the frame  12 . These serve to retain the flap  14  in a closed position. 
     It will be appreciated that by positioning the connectors  62  suitably, the pet door assembly  10  does not require customization for different screen doors. Furthermore, the connectors  62  are fastened to the inwardly facing surface  78  such that the connectors  62  or the frame  12  do not interfere with a complementary screen door in the case of glass sliding doors. Still further, since the connectors  62  are received in the respective channels  28 , the pet door assembly  10  is inhibited from both upward and sideways movement. This provides a relatively rigid connection that can withstand use by energetic, larger pets. 
     In  FIG. 6 , reference numeral  90  generally indicates part of an enclosure structure, in accordance with the invention. With reference to  FIGS. 1 to 5 , like reference numerals refer to like parts, unless otherwise specified. 
     The enclosure structure  90  includes a number of wall members or walls  92 . The walls  92  are connected together to define an enclosure  94 . Each wall  92  has a frame  96  and a grille  98  mounted in the frame  96 . The grille  98  is cut away to define an opening that accommodates the pet door assembly  10 . The assembly  10  is received in the opening with an inner peripheral edge  100  defining the opening received in the channel  28 . 
     The enclosure structure  90  can be one of those used to provide an enclosure for animals or children. Thus, a pet in the enclosure is able to enter and exit the enclosure without having to be lifted over one of the walls  92 . 
     Applicant submits that the invention provides a convenient and simple pet door for a screen door. Of particular significance is the fact that the frame  12  is fastened to inwardly facing surfaces of a screen door frame. This inhibits interference in the case of glass sliding doors. Furthermore, the use of the connectors  62  provides a convenient manner of installing the pet door assembly  10 . In particular, the use of the connectors  62  provides a means whereby a position of the closure assembly  10  can be adjusted to suit the particular screen door, without having to provide a customized closure assembly.

Summary:
A pet door assembly that includes a support structure that defines an access opening through which a pet can pass. A connecting arrangement is positioned on the support structure to permit the support structure to be connected to at least one connector fastenable to an inwardly facing surface of a closure frame. A self-closing door is mounted on the support structure to be displaceable between a closed position in which the door closes the access opening and an open position.