fig1 a and 1b illustrate the present invention , comprising a frame 10 positioned on a top rim 13 of a commercially available litter box 12 . the height of the frame 10 is sufficient to prevent waste from being displaced out of the litter box 12 . one embodiment of the present invention provides a frame 10 including a plurality of upright members 20 , each of the upright members 20 connected to the adjacent upright member by a top horizontal cross member 16 and a bottom horizontal cross member 18 . the bottom cross member 18 is formed to engage with the rim 13 of the litter box 12 so as to be structurally stable on the litter box 12 . the bottom cross member 18 may be flat and include at least two corner brackets 22 extending down from a bottom cross member 18 which has no specific bottom profile . the corner brackets 22 serve to stabilize the surround on the rim 13 of the litter box 12 . in fig1 b , the depicted embodiment shows a frame 10 with a releasably attached side liner 28 covering the inner surface of the frame 10 on three sides . one side is left unlined to create an entry opening 30 . this embodiment shows a plurality of upright members 20 which connect to adjacent upright members 20 by a plurality of bottom cross members 18 . in this embodiment , there is no bottom cross member 18 on the side of the frame 10 which has the entry opening 30 . each of the upright members 20 has a fastener 24 located on the inner surface near the top of the upright member 20 . the side liner 28 extends downward from the fasteners 24 along the inner surface of the frame 10 . the bottom edge 27 of the side liner 28 hangs below the upper rim 13 of the litter box 12 . a plurality of brackets 22 extend down from the bottom cross members 18 far enough below the upper rim 13 of the litter box 12 to prevent the frame 10 from moving back and forth or side to side on the litter box 12 . as seen in fig2 a , on the interior surface of the frame 10 , a side liner 28 is extended downward from the frame 10 into the litter box 12 . it is important that the bottom edge 27 of side liner 28 extends below rim 13 where the frame 10 meets the litter box 12 . this serves to prevent waste from escaping through the transition area 17 where the surround frame 10 meets the litter box 12 . fasteners 24 may be used to attach the liner 28 to the frame 10 . the embodiment shown in fig2 a includes a removable side liner 28 that is fastened to the top cross member 16 such that the removable liner extends at the inside of the top cross members 16 down below the upper rim 13 of the litter box 12 , see also fig3 a . fig2 b shows an overall , or full liner 26 which covers the entire inside surface of the litter box 12 and extends upward to form the liner 26 for the frame 10 . at least one opening 30 is provided in the removable full liner 26 as shown in fig2 b . the frame 10 of fig2 a shows an embodiment with a side liner 28 , which is attached by a fastener 24 at upright member 14 which forms one side of the entry opening , and the side liner 28 continues around the inner surface of the frame 10 and attaches to the upright member 14 that forms the other side of the entry opening 30 . fig2 a shows that the side liner 28 has been draped in a manner to allow the frame opening 30 on the long side of the box to remain open , while the liner covers the optional frame opening 31 on the short side of the box . in this embodiment , frame 10 includes four upright members 20 , one positioned in each corner of the frame 10 . the bottom cross member 18 includes four corner brackets 22 for engaging with the rim 13 of the litter box 12 and stabilizing the frame 10 . it is also possible to use only two corner brackets 22 positioned diagonally from one another to provide stability ( not shown ). it is also possible to use stabilizing downward extensions 39 in locations other than the corners , see fig4 a . fig2 b shows that the removable liner 26 is fastened to the inside of the top cross member 16 with adhesive tape 23 . fastener 24 , shown in fig2 a can be implemented by a variety of fastening means , including , but not limited to , clamps , clips , hook and loop fastener , or tape . as mentioned above , an opening 30 is provided for the pet to enter the litter box 12 . an opening 30 is provided in the frame 10 and an opening in the full liner 26 is formed by two vertical cut lines 34 or perforated vertical areas 34 ′ that can be pulled open . the opening can also be formed by a flap which can be left open or sealed closed with an attached adhesive strip along each vertical edge covered by a removable material that covers the adhesive strip if the flap is to be left open ( not shown ). the opening 30 may be left open by folding the liner over the box as shown in fig2 b . as discussed , in the embodiment shown in fig2 b , the removable full liner 26 is a bag having a bottom which is dimensioned to cover the entire inner surface of the litter box 12 and which has sides that extend up to the top cross member 16 of the surround frame 10 , see also fig3 b . this type of full liner 26 may be attached to the top cross member 16 in the same way in which the side liner 28 is attached , that is by clamping 24 , with adhesive tape 23 , or any other fastening means . as shown in fig3 a , the bottom 32 of the frame 10 may be formed to engage with the upper rim 13 of the litter box 12 in a secure manner . in another embodiment , the bottom 32 of the frame 10 may be manufactured with a ledge ( not shown ) that extends down below and along the inner or outer surface of the rim 13 of the litter box 12 . fig3 b shows downward extensions 22 that extend below the rim 13 of the inner and / or outer surface of the litter box 12 to stabilize the frame 10 on the litter box 12 . another embodiment shown in fig4 a is contemplated , in which the present invention comprises a plurality of solid panels 40 attached in a serial manner to create walls that extend above the top of litter box 12 . the panels 40 can be permanently or releasably attached to the adjacent panel ( s ). this embodiment illustrates panels 40 connected by hinges 42 . at least one hinge 42 may include a removable pin 44 so that the plurality of solid panels 40 can be flattened . a liner can be attached by means of fasteners 24 . a plurality of stabilizing downward extensions 39 may be used to stabilize frame 10 on the litter box 12 . yet another embodiment of the surround as shown in fig4 b may include solid side panels 46 which are permanently connected and can be secured on or around a litter box . in the embodiment shown , where the adjacent panels 46 attach , there is a vertical weakened area 48 that is suitable for folding the solid panel 46 at the area 48 to either form a surround , or to fold it flat . it is possible to use a disposable liner ( not shown ) such as 26 or 28 attached with fasteners 24 with the solid panel surround in a similar fashion as discussed regarding the other embodiments . the entry opening 30 into the box can be formed by one or more openings 30 in the solid panels 46 , or by having two of the panels 46 left unconnected , as in a three - sided embodiment such as that illustrated in fig1 b . another embodiment of the frame 10 shown in fig5 is contemplated in which the frame 10 is made of adjustable cross members 16 and 18 , thereby making frame 10 adjustable in size . the cross members may comprise adjacent parts of different thicknesses , such that the thinner part 51 fits into a hollow area within the thicker part 52 , and the parts 51 and 52 releasably interlock to a fixed position relative to each other by some means , such as a locking screw 55 which tightens against the inner part 51 . while this drawing showed a specific adjustment means , those skilled in the art will recognize that there are a variety of possible adjustment means that can be used without departing from the scope and purpose of the disclosed invention . the bottom cross members 18 have extensions 23 that curve around the litter box rim 13 to stabilize the frame 10 on the litter box 12 . yet another embodiment of the surround is shown in fig6 a and fig6 b . a free standing upright support 60 can be secured in each corner of a standard litter box 12 . the bottom 64 of the support 60 has an l - shaped channel 62 that curves to fit the rim 13 and corner of the litter box 12 . the upright support 60 can have a means to secure it to or against the litter box 12 , such as an adjustment screw 55 . as shown in fig6 b , the upright support 60 has a fastener 24 , which is used to attach a removable liner 28 which is draped down from the fasteners 24 along the inner surface of the supports 60 . an entry opening 30 is formed by leaving one area between two supports 60 undraped by the liner 28 . the bottom 64 of the upright support 60 is formed in a manner to engage securely with the upper rim 13 of the litter box 12 . it is understood that the frame or panels of the present invention can be manufactured in many variations , including , but not limited to : adjustable in size so the user can customize the length , width , and / or height of the frame or panels by such means as telescoping horizontal and / or vertical members with a ratcheted or locking system or attachment to stabilize or fix the desired dimensions ; or horizontal , vertical , or combination configuration of frame members that can be attached together at more than one point or configuration to allow for size adjustment ; or varying sized horizontal and / or vertical members that can be attached together to adjust the length and / or width of the frame or panels . the frame or panels can be manufactured as one piece ; or as multiple parts or pieces that may include hinges , may be adjustable in size , or may be detachable , to allow the frame or panels to be collapsed or folded for cleaning or in order to take up less shelf , storage , packaging , or shipping space . thus , while there have been shown and described and pointed out fundamental novel features of the invention as applied to preferred embodiments thereof , it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated , and in their operation , may be made by those skilled in the art without departing from the spirit of the invention . for example , it is expressly intended that all combinations of those elements and / or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention . substitutions of elements from one described embodiment to another are also fully intended and contemplated . it is also to be understood that the drawings are not necessarily drawn to scale but that they are merely conceptual in nature . it is the intention , therefore , to be limited only as indicated by the scope of the claims appended hereto .
a litter box containment system is disclosed . the system provides an extension or enclosure that adapts to an existing litter box , and increases the height of the sides , serving to keep in animal waste and litter . the system also provides for multiple possible entrances that provide easy access for an animal , while still providing extended protection against escaping animal waste and litter .