Liner for a litter box

A disposable plastic film liner for an animal litter box is improved by having an opening in the liner, at about the center thereof, which communicates with a collapsible pocket adapted to lie flat beneath the liner when in use lining the inside of the litter box. As the liner is lifted out of the box by gripping and raising opposite ends of the plastic, the soiled adsorbent runs into the pocket and can then be easily disposed of.

This invention relates to disposable plastic film liners for animal litter 
boxes. More particularly, it relates to an improvement in such liners 
whereby they are less apt to contribute to spilling of the soiled 
adsorbent when liner and adsorbent are removed from the box. 
Animal litter boxes are frequently lined with a disposable plastic film 
liner before placing a layer of particulate, sanitary adsorbent in them. 
The purpose of the liner is to keep the inner surface of the box clean and 
to facilitate removal of the adsorbent, after it has become soiled, from 
the box to a waste receptacle. Heretofore these liners have either been 
bags or flat rectangles of plastic film, and they have had definite 
drawbacks. 
Bag type liners are disclosed, for example, in U.S. Pat. Nos. 3,227,137; 
3,684,155; 3,771,493; and 3,831,557. Unless the configuration of such a 
liner fits precisely the contour of the interior of the litter box, it 
tends to bunch up, or gather in loose folds, under the adsorbent, and be 
caught and torn by the claws of the animal using the box. A cat, for 
example, will frequently tear a bag liner when it digs a depression in the 
adsorbent layer, preparatory to using the commode, as well as when it 
thrusts its hind legs in order to cover its waste. Spillage of soiled 
adsorbent through the tear holes results when the liner is later lifted 
out of the box. 
Flat, rectangular liners tend to hug the bottom of the box, and thus suffer 
fewer claw tears. However, flat liners are practically impossible to lift 
out of the box at changing time without some of the soiled adsorbent 
spilling over the liner's edge, unless two people do it or the liners are 
ridiculously oversized for the box, in which case they waste a good deal 
of material and present an unaesthetic overhang around all four sides of 
the box. Contoured, or fitted, liners suffer the same drawback. In 
addition, they only avoid bunching up, and resultant tear holes, when they 
are used with the proper size box--not too large and not too small. 
It is generally recognized by pet owners, especially the owners of cats, 
that the task of removing soiled litter box adsorbent is unpleasant 
enough, without having to cope with spillages in the bargain. The present 
invention provides a solution to the problem: a disposable liner which 
resists tearing by the pet's claws, yet can be easily and quickly removed 
from the litter box along with the soiled adsorbent. What is more, one 
size of the liner of the present invention can easily fit a wide range of 
litter box sizes. 
The present invention improves a flat, disposable, plastic film liner for 
an animal litter box by providing an opening in the liner, at about its 
center, which communicates with a collapsible pocket adapted to lie flat 
beneath the liner when it is inside the litter box. When in position in 
the box, beneath a layer of adsorbent, the liner lies flat against the 
bottom of the box, and thus is not as susceptible to claw tears as are the 
bag type liners. But when the liner is grasped by its opposite edges and 
lifted out of the box, the pocket falls down, opens, and receives the 
soiled adsorbent, which runs into it by force of gravity. Securely caught 
in the pocket, the adsorbent can then be carried to a waste receptacle 
without spillage. 
Even if the liner of the present invention is used in a litter box for an 
animal which has an especial propensity for clawing holes in liners, it is 
still likely that only the top layer of film will be torn. The walls of 
the pocket, which lie beneath the top layer of plastic, will in all 
likelihood remain unbroken. What spillage does occur upon removal of a 
liner torn in that manner is a very small amount, because it occurs only 
for the brief instant that the adsorbent is running down the inclined top 
layer of film into the pocket. Also, the spilled adsorbent falls inside 
the litter box, where it can be cleaned up more easily than if spilled on 
the floor enroute to a trash receptacle. 
The type and thickness of the plastic film used to make the liner of the 
present invention is not critical. Low density polyethylene film, like 
that commonly used for household trash bags, is quite suitable. The film 
should be thick enough, of course, to support the adsorbent, and 
preferably thick enough to give some resistance to claw tears. A thickness 
in the range of about 0.8 to 2.0 mil, e.g., about 1.0 to 1.5 mil, will 
suffice. 
Cat litter boxes which are on the market today generally have a rectangular 
configuration (top view), and are essentially composed of a bottom and 
four sides. Accordingly, it is preferred that the liner of the present 
invention, when flattened out, also be shaped like a rectangle. 
The opening in the liner is advantageously a transverse slit which extends 
all or part of the way across the liner. The pocket is preferably shaped 
so as to be collapsible into a flat rectangle which can lay to one side of 
the opening, beneath the liner, when the liner is laying in the litter 
box. 
As mentioned above, an advantageous feature of the liner of the present 
invention is that it does not have to be specially sized for the box with 
which it is used, as, for example, square bottom bag liners must be. All 
that is required is that the pocket be large enough to hold all of the 
adsorbent, and that the liner be long enough and wide enough to cover the 
entire interior of the box. 
Preferably the litter box with which the liner of the present invention is 
used will have means for releasably holding the liner to the top of the 
sides of the box. A rim, or partial cover, which fits tightly around the 
top of the sides of the box, clamping the peripheral margin of the liner 
between the top of the sides of the box and the rim, is an example of such 
holding means.

Looking at FIGS. 1 and 2, it is seen that the liner 10 is made of a single 
piece of transparent, thermoplastic film, originally in the shape of an 
elongated rectangle. A transverse fold 11 is taken in the center of the 
plastic film, and the edges 12 of the fold are shut by L-shaped seams 13, 
which are heat pressed into the plastic. As a result, fold 11 has the 
configuration and function of a pocket, which is in communication with 
transverse slit 14, which extends substantially all the way across the 
liner. 
Looking now at FIG. 3 of the drawings, it is seen that liner 10 is placed 
in a standard, molded plastic, cat litter box 15 (shown in greater detail 
in U.S. Pat. No. 3,831,557), so that pocket 11 (shown by broken lines) of 
liner 10 lies flat beneath the liner and to the left side of transverse 
slit 14. 
Sanitary adsorbent 16 is poured into box 15, on top of liner 10. Before 
putting the commode to use, rim 20, which is hinged to the top of one of 
the side walls of box 15, is lowered into place (not shown in the 
drawings) so that it fits tightly around the top of the sides of box 15. 
Flexible locking tabs 21 releasably hold lid 20 in the lowered position, 
thus clamping the peripheral margin of liner 10 between rim 20 and the top 
of the sides of box 15. 
When adsorbent 16 becomes soiled and it is desired to replace it, FIG. 4 
shows how the opposite ends 17 and 18 of liner 10 are separately gathered 
together in one's hands and then lifted up so as to suspend the liner like 
a hammock. The weight of the soiled adsorbent 16 forces open slit 14 and 
the adsorbent slides into pocket 11 without spilling over the sides of the 
liner. Because liner 10 has lain substantially flat in box 15, with pocket 
11 protected beneath a top layer of film, no claw holes appear in the 
liner for escape of the adsorbent. 
Ends 17 and 18 of liner 10 are then brought together (FIG. 5) and tied with 
bag closure 19 (FIG. 6), in which condition the liner and its contents are 
easily and neatly disposed of.