Abstract:
A litter box for separating pet waste from litter material includes a housing having a front panel connected to a rear panel through a pair of side panels extending therebetween, and top and bottom panels extending between the front, rear and side panels to form an interior space for retaining litter and pet waste. The front panel includes an access opening such that a pet can enter into and exit from the interior space. A collection screen is removably mounted in the housing. The collection screen has a bottom wall extending at least substantially between the side panels and the top and bottom panels. The bottom wall includes openings that are sized to permit passage of clean litter material therethrough while preventing passage of pet waste when the litter box is rotated from an upright position where the bottom wall is oriented substantially vertically to a tipped position where the bottom wall is oriented substantially horizontally.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 60/157,734 filed on Oct. 5, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to small scale waste management systems, and more particularly to a litter box whose contents can be easily sifted and cleaned. 
     2. Description of the Related Art 
     Litter trays and boxes are common in households with pets, and more especially in households with cats, to collect pet waste. After repeated use, solid pet waste and coagulated litter clumps from pet urine foul the litter box and cause unpleasant odors, necessitating the frequent replacement, or sifting, of the litter by the pet owner. This task is not pleasant. Accordingly, a number of prior art products have addressed the need for a litter box that separates pet waste and clumps from clean litter. 
     There are, however, a number of disadvantages associated with existing litter boxes. Some require the user to flip the litter box 180°, while others require the user to flip the litter box 360°. Some require the user to use a complicated tilting, rotating motion to sift the litter, or to lift the sifting tray up through the litter to separate the pet waste, then rotate the box back approximately 90° to empty the main pan of litter so the sifting tray can be replaced. Finally, others mount the litter box on a frame, upon which the user rotates the box. 
     Accordingly, there exists a need for a litter box that is simple in design, easy to use, and inexpensive to construct. 
     SUMMARY OF THE INVENTION 
     According to the invention, a litter box is provided for separating pet waste from litter material. The litter box includes a housing having a front panel connected to a rear panel through a pair of side panels extending therebetween, and top and bottom panels extending between the front, rear and side panels to form an interior space for retaining litter and pet waste. The front panel includes an access opening such that a pet can enter into and exit from the interior space. A collection screen is removably mounted in the housing. The collection screen has a bottom wall that extends at least substantially between the side panels and the top and bottom panels, e.g. the edges of the bottom wall may be spaced from, or in contact with, the panels. In one preferred arrangement, the edge of the bottom wall close to the bottom panel may be spaced a sufficient distance from the bottom panel to allow for clearance of clean litter material when the collection screen is installed in the housing. The bottom wall includes openings that are sized to permit passage of clean litter material therethrough while preventing passage of pet waste when the litter box is rotated from an upright position where the bottom wall is oriented generally vertically to a tipped position where the bottom wall is oriented generally horizontally. 
     Further according to the invention, a litter box for separating pet waste from litter material comprises a housing having a front panel connected to a rear panel through a pair of side panels extending therebetween, and top and bottom panels extending between the front, rear and side panels to form an interior space for retaining litter and pet waste. The front panel includes an access opening such that a pet can enter into and exit from the interior space. A collection screen is removably mounted in the housing. The collection screen has a bottom wall extending at least substantially between the side panels and the top and bottom panels. The bottom wall includes openings that are sized to permit passage of clean litter material therethrough while preventing passage of pet waste when the litter box is rotated approximately 90° from an upright position where the bottom wall is oriented substantially vertically to a tipped position where the bottom wall is oriented substantially horizontally. The collection screen further includes side walls that extend along opposite sides of the bottom wall and an end plate connected to an upper end of the side walls and bottom wall to form a volume for holding the pet waste. An area of the bottom wall is preferably void of the openings. The bottom wall is spaced from the rear panel to provide a volume into which the clean litter material can be collected when the litter box is rotated from the upright position to the tipped position. The upper panel comprises the end plate of the connection screen and a removable lid. A panel portion extends between the bottom panel and the rear panel to facilitate rotation of the litter box between the upright and tipped positions. A lower pair of guide ribs are located on each side panel at least adjacent to the bottom panel and an upper pair of guide ribs are located on each side panel at least adjacent to the top panel. The upper pairs of guide ribs are in alignment with a respective one of the lower pairs of guide ribs. The side walls of the collection screen are slidably received between the upper and lower pairs of guide ribs. 
     Other objects and advantages of the invention will become apparent upon reading the following detailed description and appended claims, and upon reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front isometric view of a litter box according to the invention; 
     FIG. 2 is a front isometric exploded view of the litter box of FIG. 1; 
     FIG. 3 is a front isometric view of a lower housing portion of the litter box; 
     FIG. 4 is a front isometric view of an upper housing portion of the litter box; 
     FIG. 5 is bottom isometric view of an access lid that forms part of the litter box of FIG. 1; 
     FIG. 6 is a cross sectional view of the upper housing portion taken along line  6 — 6  of FIG. 4; 
     FIG. 7 is a cross sectional view of the lower housing portion taken along line  7 — 7  of FIG. 3; and 
     FIG. 8 is a rear isometric view of a collection screen that forms part of the litter box of FIG.  1 . 
    
    
     It is noted that the drawings are intended to depict only typical embodiments of the invention, and therefore should not be considered as limiting in scope. The invention will now be described in greater detail with reference to the accompanying drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings, and to FIGS. 1 and 2 in particular, a litter box  10  according to the invention includes a housing  12 , an access lid  14  removably supported on the housing, and a collection screen  16  removable installed in the housing. 
     The housing  12  includes a lower housing portion  18  and an upper housing portion  20  connected to the lower housing portion, preferably through a snap-fit engagement, as will be described in greater detail below. The lower and upper housing portions together form an interior  22  with a pet access port  24  that opens into the interior  22 . 
     With reference now to FIGS. 3 and 7, the lower housing portion  18  is preferably integrally formed of a plastic material and includes a front panel  26  connected to a rear panel  28  through a pair of side panels  30 ,  32 . A bottom panel  34  extends between the side panels  30 ,  32  and is connected to the front panel  26  and the rear panel  28  by a front chamfered panel portion  36  and a rear chamfered panel portion  38 , respectively. The front and rear chamfered portions facilitate rotation of the litter box  10 , as will be described in greater detail below. The bottom panel together with the side, front and rear panels form a tray into which cat litter, bedding material, or the like may be contained. Preferably, the panels are curved or chamfered at their intersection. The access port  24  is formed in the front panel  26  and preferably includes a curved bottom edge  40  that extends between curved side edges  42 ,  44 . The curved edges of the opening  24  assure the safe entry and exit of pets such as cats since there are no sharp edges to rub against. The bottom edge  40  also serves as a litter bar to help keep the litter or bedding material inside the box during use. 
     Guide ribs  46  and  48  are formed on the inner surface  50  of each of the side panels  30 ,  32  in opposing relationship and normally extend upwardly from the bottom panel  34 . A lower end of each guide rib  46  is preferably located at the intersection  51  of the rear chamfered panel portion  38  and the bottom panel  34 . The guide ribs  38  preferably extend substantially parallel to the guide ribs  36  and are spaced therefrom a sufficient distance to receive side walls  52 ,  54  (FIG. 2) of the collection screen  16 . Although the guide ribs  36  and  38  are shown as extending substantially parallel to each other, it is to be understood that they may be nonparallel, especially when the side walls of the collection screen  16  are slanted. Feet  56  project downwardly from the bottom panel  34  to space the bottom panel from a floor or other support surface. Preferably, four feet are integrally molded with the bottom panel. Slots  58 ,  60  extend through each side wall  30 ,  32  for securing the upper housing portion  20  to the lower housing portion  18 , as will be described in greater detail below. 
     With reference now to FIGS. 4 and 6, the upper housing portion  20  is preferably integrally formed of a plastic material and includes a front panel  62  connected to a rear panel  64  through a pair of side panels  66 ,  68 . Preferably, the front panel  62  is substantially parallel to the rear chamfered panel portion  38  while the rear panel  64  is substantially parallel to the front chamfered panel portion  36  when the upper and lower housing portions are assembled together. Likewise, the side panels  66  and  68  are preferably coplanar with the side panels  30  and  32 , respectively, of the lower housing portion  18 . The upper edges  80 ,  82 ,  84  and  86  of the panels  62 ,  64 ,  66  and  68 , respectively, together define an opening  88  that receives the access lid  14  and collection screen  16 . 
     A front pocket  70  with a forward facing opening  72  is formed in the front panel  62 , and a rear pocket  74  with a rearward facing opening  76  is formed in the rear panel  64 . The pockets  70 ,  74  serve as handles that may be grasped by a person to facilitate holding, transporting, and rotating the litter box  10 . 
     Guide ribs  90  and  92  are formed on the inner surface  94  of each of the side panels  66 ,  68  in opposing relationship and normally extend downwardly from the upper edges  84 ,  86 . An upper end of each guide rib  90  is preferably located at the intersection  96  of the rear panel  64  and the respective side panel  66 ,  68 . The guide ribs  90  and  92  are preferably collinear with the guide ribs  46  and  48 , respectively, when the upper and lower housing portions are assembled together to receive the side walls  52 ,  54  (FIG. 2) of the collection screen  16 . Although the guide ribs  90  and  92  are shown as extending substantially parallel to each other, it is to be understood that they may be nonparallel, especially when the side walls of the collection screen  16  are slanted. 
     Fingers  98 ,  100  are formed on each of the side panels  66  and  68  in opposing relationship. The fingers  98 ,  100  are preferably integrally formed as a depression in each of the side panels and extend below lower edges  104  and  106  of the side panels  66  and  68 , respectively, in cantilever fashion. An outwardly projecting catch  102  is formed at the lower end of each finger  98 ,  100  and is sized to be received in one of the slots  58 ,  60  (FIG. 2) of the lower housing portion  18 . Engagement of the catches  102  with their respective slots secures the lower and upper housing portions together during assembly. The cantilever nature of the fingers  98 ,  100 , allows some flexing of the fingers during assembly and disassembly. The lower and upper housing portions may be disassembled by inserting a flat-head screw driver or other object into the slots  58 ,  60  to press against the catches  102  and release them from the slots. 
     In an alternative arrangement, the slots in the lower housing portion may be replaced with inner projections (not shown) to receive the catches of the upper housing portion. Other means of attachment may also be provided, such as mechanical fasteners, ultrasonic welding, adhesives, and so on. Alternatively, the upper and lower housing portions may be integrally formed as a unitary structure during manufacture. 
     A lower flange  105  extends around the lower periphery of the upper housing portion  20  and is received over an upper peripheral edge  107  of the lower housing portion  18  when assembled. A front portion of the lower flange  105  serves as an upper edge of the pet access port  24 . 
     Referring now to FIGS. 1,  2  and  5 , the access lid  14  includes a depression  108  that extends downwardly from a plate  112  and a hollow handle  110  that is formed in the depression  108  and extends upwardly toward the plate  112 . A continuous lip  114  extends around the periphery of the plate  112  and is spaced from outer edges  116 ,  118 ,  120 , and  122  of the plate to form a peripheral support flange  124 . When assembled, the lip  114  is located adjacent the upper edges  80 ,  84  and  86  (FIG. 4) of the upper housing portion  20 , and the peripheral support flange  124  is supported on the upper edges  80 ,  84  and  86 . 
     With reference now to FIGS. 2 and 8, the collection screen  16  includes the side walls  52 ,  54  that extend from opposite ends of an end plate  130  and a bottom wall  132  that extends from the end plate  130  and between the side walls  52 ,  54 . The collection screen  16  is preferably of unitary construction and molded from a suitable plastic material. However, the collection screen may be constructed of separate components and any suitable material. The side walls together with the end plate and bottom wall of the collection screen form a tray for receiving pet waste, litter clumps, and other objects, and help prevent such objects from falling off the collection screen when removed from the litter box. A plurality of openings or perforations  136  are formed in the bottom wall  132  to allow cat litter or bedding material to pass or sift therethrough during a cleaning operation, as will be described in greater detail below. 
     As shown, the side walls  52 ,  54  of the collection screen slide between the guide ribs  90 ,  92  on the side panels  66 ,  68  of the upper housing portion  20  and the guide ribs  46 ,  48  on the side panels  30 ,  32  of the lower housing portion  18 . When the collection screen  16  is installed in the litter box  10 , the end plate  130  is supported by the upper edges  82 ,  84  and  86  of the upper housing portion  20  and the guide ribs hold the collection screen  16  in place. A handle  138  extends outwardly from the end plate  130  to facilitate removal and installation of the collection screen  16 . Preferably, an outer surface  140  of the end plate  130  is coplanar with an upper surface  142  of the plate  112 . 
     Preferably, the bottom wall  132  of the collection screen  16  includes a solid portion  144  adjacent the end plate  130  to create a volume within which the litter waste may be collected and contained during transportation from the litter box to a waste receptacle. A longitudinal stop bar  146  is formed adjacent a lower edge  148  of the wall  132 . As the user removes the tray from the litter box, the stop bar will engage the upper edge  82  of the upper housing portion  20  to help prevent abrupt falling movement and consequent spillage of the collection screen&#39;s contents as the lower edge  148  of the collection screen clears the upper edge  82 , especially when the collection screen is oriented in the horizontal position, as will be described in greater detail below. The stop bar  146  requires the user to stop and lift the screen tray until the stop bar clears the upper edge  82  before the screen tray can be separated from the housing. 
     In use, the user cleans the litter box  10  by rotating it backwards approximately 90° from the upright position to a tipped position where the litter box is supported on the rear panel  28 . The rear chamfered panel portion  38  facilitates rotation of the litter box between the upright and tipped positions. As the litter box rotates backwards, the litter moves toward the rear panel  28  and onto the collection screen  16 . Uncoagulated litter falls through the screen into a retention chamber  150  located rearwardly of the collection screen and defined by the rear panel  28 , the chamfered panel portions  38  and  64 , and the side walls  30 ,  32  and  66 ,  68  of the lower and upper housing portions, respectively. Coagulated litter and other waste matter that cannot fall through the collection screen remains on top of the bottom wall  132  of the collection screen, with the collection screen in a generally horizontal position. The user then grasps the handle  138  and pulls the collection screen out of the litter box, being careful to lift the collection screen such that the stop bar clears the upper edge  82 . The coagulated litter and other objects can then be disposed of in a suitable receptacle. The user then rotates the litter box to the original upright position from the tipped position, causing the screened litter to return to the bottom panel  34 . The collection screen  16  can then be replaced. Additional clean litter may be added to the litter box through the removable access lid  14 . Moreover, the user may easily clean the removable screen tray before reinsertion into the litter box. 
     It is to be understood that the terms upper, lower, side, front, rear, bottom, top, and their respective derivatives and equivalents as may be used herein refer to relative, rather than absolute positions and/or orientations. 
     While the invention has been taught with specific reference to these embodiments, those skilled in the art will recognize that changes can be made in form and detail without departing from the spirit and the scope of the invention. The described embodiments are to be considered in all respects only as illustrative and not restrictive. By way of example, the rear chamfered panel may be replaced with a more rounded portion, and may be located only between the bottom and rear panels, since the litter box is rotated only between these panels. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.