Abstrict A cat litter box with a mechanism for screening and draining reuseable,
liquid-impervious granular material contained in the box, the box
having a housing with a container, the container having an inner
compartment with holes for holding the granular material and draining
liquids, and an outer compartment for receiving drained liquids,
the inner compartment having a screen, wherein the mechanism both
raises the screen through the granular material to separate solid
wastes, and tips the container to drain the liquid wastes and separated
solids into a collection box for removal, and lowers the container,
returning the screen to the inner compartment and redistributing
the granular material over the screen before the container seats
in the housing for reuse.
Claims What is claimed is:
1. A litter box for cats and other household pets comprising:
(a) a container having walls and a bottom with holes for draining
liquids;
(b) a substantially impervious granular material contained in the
container covering the bottom of the container and sized larger
than the container bottom holes;
(c) a screen member with screening elements spaced to pass the
granular material and collect solid waste material typically discharged
from a household pet using the litter box, the screen member being
positioned over the container bottom under the granular material;
(d) liquid receiving means for receiving liquids discharged into
the container and passing through the holes in the container bottom;
(e) waste collection means for receiving solids from the container
and liquids from the liquid collection means;
(f) actuation and deposit means for actuating the screening of
solids from the container and the draining of liquids from the liquid
collection means, and depositing screened solids and drained liquids
into the waste collection means.
2. The litter box of claim 1 wherein the liquid collection means
comprises a compartment under the bottom of the container adapted
to collect and hold liquids.
3. The litter box of claim 1 wherein the actuation and deposit
means includes a first mechanism having means for passing the screen
member through the granular material, separating the solid material
from the granular material.
4. The litter box of claim 3 having a housing structure, on which
the first mechanism is mounted, the first mechanism including lift
means connected to the screen member for lifting the screen member
through the granular material.
5. The litter box of claim 4 wherein the lift means comprises an
actuating handle, a spindle, a rack and pinion mechanism connecting
the actuating handle to the spindle and adapted to rotate the spindle
on displacement of the handle, and, a connecting means for connecting
the screen member to the spindle.
6. The litter box of claim 5 wherein the screen member is constructed
with sides, a bottom comprised of a series of spaces and an open
end, and, said container is constructed with a top open portion
and a top covered portion, the screen member being positioned on
the container bottom below the open portion, said lift means including
link members connected to said wire connecting means and to the
sides of the screen member, said link members being adapted to raise
the open end of the screen member to the top covered portion of
the container on actuation of said first mechanism.
7. The litter box of claim 6 including cooperating detent retaining
means on the container and on the screen member for retaining the
open end of the screen member at the top covered portion of the
container.
8. The litter box of claim 3 wherein the actuation and deposit
means includes a second mechanism having means for tilting the container
and screen member in a manner adapted to deposit liquids from the
liquid collection means and screened solids from the screen member
into the waste collection means.
9. The litter box of claim 8 wherein the actuation and deposit
means includes a third mechanism for distributing granular material
across the container bottom over the screen member.
10. The litter box of claim 8 wherein the container includes walled
front, back, sides, and a top with an open portion proximate the
front and a cover portion proximate the back, the waste collection
means being positioned adjacent the container back, wherein the
second mechanism includes a frame structure with a cross bar and
linkage assembly, the cross bar and linkage assembly having a hand
operated cross bar, vertical link members connected to the cross
bar at one end and pivotally connected to a link unit with end links
pivotally connected to the frame structure in the manner of levers
arranged PG,20 on each side of the container, the end links having
an interconnecting cross member under the container, whereby on
manual depression of the cross bar the container is tilted upward
such that the back wall of the container is over the liquid collection
means in a position that drains liquids from the liquid receiving
means and deposits separated solids from the screen into the collection
means.
11. The litter box of claim 10 wherein the actuating and deposit
means includes: a third mechanism comprising a support means for
retaining the back of the container elevated above the waste collection
means when the front is returned to a lowered position, whereby
the granular material spreads over the screen member; and, a release
means for releasing the back of the container to return the container
to a usable position.
12. The litter box of claim 11 wherein the support means comprises
a cam assembly with support cams on a shaft connected to the frame
structure and a wire assembly with suspension wires connected to
the cam assembly and the container, the cam assembly having bias
means for winding the wires on the cams as the container is raised
by the cross bar and linkage assembly.
13. The litter box of claim 11 wherein the release means comprises
a notched detent lever with a bias spring mounted on the frame structure
and a detent cam with a detent mounted on the shaft of the cam assembly.
Description BACKGROUND OF THE INVENTION
This invention relates to a cat litter box with a mechanism for
screening and draining reusable cat litter. Conventional cat litter
boxes comprise an open container into which one or two inches of
granular absorbent material is placed. Periodically the litter material
is removed, discarded and replaced with new material. Optionally,
special tools are provided to scoop and remove fecal matter to extend
the life of the litter material. However, after being impregnated
with cat urine, the absorbent litter material produces odor that
requires the litter to be removed because it has become repugnant
to either the cat or the cat's owner, or both.
Certain conveniences have been devised for assisting in the use
and operation of a cat litter box. For example, in the patent of
Ellis, U.S. Pat. No. 3831557 entitled CAT LITTER BOX, a molded
container is disclosed that includes an impervious liner. Periodically,
the liner and contained litter may be removed and discarded. The
discarded liner is replaced with a new liner and new litter material
is placed over the liner in the box. In the patents of Rigney, U.S.
Pat. No. 3809013 entitled DISPOSAL INSERT FOR LITTER BOX, and
Harrington, U.S. Pat. No. 4312295 entitled CAT BOX LITTER SCREENING
DEVICE, a series of stacked liners with holes or apertures are provided
to allow litter placed on top of the liners in a cat litter box
to be screened such that bulk material is removed and the life of
the remaining litter is extended. While certain odor absorbing or
scent masking chemicals may be applied to the cat litter to further
extend the life of the litter material, the material must usually
be discarded well before it becomes saturated with urine.
The requirement to periodically change and remove the cat litter
is a necessary nuisance in the ownership of a cat. The cat owner
must be continually conscious of the existing supply of absorbent
cat litter and must always be attentive to the current state of
the litter box.
The mechanical cat litter box of this invention is designed to
minimize the task of preparing a cat litter box and maintaining
it in a condition that is usable and inoffensive to both cat and
owner.
SUMMARY OF THE INVENTION
The mechanical cat litter box of this invention comprises a container
for holding a nonabsorbent litter material that is periodically
screened and drained by a mechanism actuated by simple push-pull
hand bars. Instead of using a conventional absorbent litter material,
the mechanical litter box of this invention operates by use of an
impervious granular material that does not absorb the urine and
moisture but allows such to drain through the material to the bottom
of a container basin for collection and periodic removal. The litter
box is equipped with a mechanism for straining the fecal matter
from the container and draining the liquid matter from the basin.
The mechanical litter box of this invention includes a frame and
a base pad. Positioned on the base pad and connected to the frame
is a litter container having an inner and outer compartment. The
litter is contained in the inner compartment. The outer compartment
comprises a basin for collection of liquid that passes through holes
in the bottom of the inner compartment. The litter container has
side walls and a top with a front open portion and a rearward covered
portion. Located in the forward portion of the container on the
bottom of the inner compartment is a screen. The screen is sized
and constructed to pass special granular litter material while retaining
larger fecal material when the screen is drawn through the liquid
impervious cat litter. In a two stage actuation process initiated
by first and second plunger bars, the screen is lifted through the
container and the container and displaced screen are raised and
tipped to deposit the liquids and solids into a collection box.
Once the liquids are drained and the solids deposited in the box,
the actuating mechanism can be dropping the screen to the bottom
of the container and redistributing the displaced impervious litter
material over the screen as the litter container first shifts to
a downward tilted position before dropping back onto the base pad.
The collection box can be emptied in any sanitary facility such
as a toilet.
When the self draining litter box of this invention is used, a
non absorbent litter material can be used over and over. The litter
material may comprise the colorful enamel coated pebble material
sold in tropical fish stores, may comprise a coated expanded polymer
that is light in weight, or any similar liquid-impervious granular
material. During use of the mechanical litter box unit, the litter
material can be repeatedly sprayed with a deodorized flush liquid
from a conventional squeeze bottle. After draining through the impervious
litter material the deodorizing liquid mixes with the collected
urine in the under compartment or basin and is discharged with the
urine during the mechanical flushing operation. The actuating mechanism
detailed in the detailed description of the preferred embodiment
mechanically accomplishes the various motions required to screen
the litter and dispose of the solid and liquid effluent. Other equivalent
mechanisms may of course be utilized to achieve the objects of this
invention. The principal object of this invention as detailed hereafter
is to provide a self-draining litter box having liquid-impervious
litter that can be periodically screened of solid matter and drained
of liquid matter by an easily operable actuating mechanism. The
actuating mechanism may be electrical, hydraulic or mechanical.
The description herein is directed to a mechanical means as a preferred
embodiment.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of the mechanical litter box
unit.
FIG. 2 is a fragmented partial cross sectional view taken along
the lines 2--2 in FIG. 1.
FIG. 3 is a front elevational view partially and cross section
of the litter box unit of FIG. 1.
FIG. 4 is a cross sectional side view taken along the lines 4--4
in FIG. 3.
FIG. 5 is a cross sectional detailed view taken along lines 5--5
in FIG. 4.
FIG. 6 is a cross sectional detailed view taken on the lines 6--6
in FIG. 1.
FIG. 7 is a cross sectional top view taken on the lines 7--7 in
FIG. 1.
FIG. 8 is a schematic view of the box unit in a first sequence
of operation.
FIG. 9 is the box unit in a second sequence of operation.
FIG. 10 is the box unit in a third sequence of operation.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1-7 of the drawings, the mechanical litter box
unit, designated generally by the reference numeral 10 is shown
in various views detailing its construction. The litter unit as
shown in FIG. 1 is constructed with a pair of side frames 12 interconnected
by thin back wall 14 and a base pad 16 which together form a housing
18 for a litter container 20 and an actuating mechanism 22. The
actuating mechanism 22 includes several sub mechanisms for accomplishing
the operations described hereinafter. In addition to the litter
container 20 is a refuse collection box 24 mounted against the back
wall 14 of the housing 18. The refuse collection box 24 has a handle
26 for removing the box through a contoured aperture 28 in one of
the side frames 12 for withdrawing the refuse collection box 24
for periodic disposal of collected waste materials.
The litter container 20 as shown most clearly in FIG. 4 is constructed
with an upper or inner compartment 30 and a lower or outer compartment
32 which forms a basin for collection of liquids that pass through
a series of holes 34 in the bottom of the inner compartment 30.
The inner compartment 30 contains a deep layer of non absorbent
granular material 36 which is sized slightly larger then the holes
34 to prevent their passage from the inner compartment to the outer
compartment. The litter container 20 is constructed with an open
portion 38 and a covered portion 40. Seated in the open portion
38 is a screen strainer 42 which has an open end wall 44 side walls
46 as shown in FIGS. 3 and 7 and a bottom screen 48 formed by
a series of elongated rods 50 connected to a cross rod 52 at the
open end of the strainer 42. The rods 50 are spaced sufficiently
close together to collect solid fecal matter while allowing the
granular material 36 to pass between adjacent rods 50. In its normal
position for use, the litter container 20 appears to a cat to be
substantially similar to the conventional litter box. The open portion
38 is sufficiently large to allow the cat to comfortably enter the
litter container for deposit or of liquid or solid wastes.
Operation of the actuating mechanism 22 is a two step operation.
In a first step depression of a plunger 54 by manual pushing on
handle 56 rotates pinion gear 58 which engages a tooth rack 60 on
the plunger shaft 62 as shown in FIGS. 3 and 4. Pinion gear 58 is
connected to spindle 64 on which is wound a wire 66. Wire 66 (displaced
for clarity in FIG. 4)branches at ring 68 to wires 70 which pass
through guide 72 and over guides 74 to connect to the central portion
of lever arm 78. Lever arm 78 has a slide connection to pivot 80
at one end and a pivotal connection to link 82 which is pivotally
connected to the top of side wall 46 at pivot 84. When the plunger
54 is depressed, the wire 66 wraps on the spindle 64 and raises
lever arm 78 thereby raising the screen strainer 42 until a detent
pin 86 engages a dimple 88 shown in phantom in FIG. 4 in the alternate
position of the strainer 42. The detent pin 86 maintains the strainer
in a position in which the end of the bottom screen 48 is juxtaposed
to the top cover 90 over the covered portion of the container 20.
The detent pin 86 is shown in cross section in FIG. 5 being positioned
in a housing 92 on the container 20 with the detent pin being biased
by a small compression spring 94.
Once the screen strainer 42 has been raised to the position shown
in phantom in FIG. 4 the litter container 20 can be tipped by use
of a cross bar mechanism 94. The cross bar mechanism 94 has a manually
operated cross bar 96 connected to two vertical link members 98
positioned proximate the side frames 12 inside the housing 18. The
vertical link members 98 connect by pivotal connections 100 and
102 to intermediate link 104 and elongated end length 106. The end
link 106 connects to a pivot bracket 108 that has a cross member
110 under the litter container 20 having a similar pivot bracket
108 on the other side of the litter container for connection to
an identical link assemblage. The litter container 20 has two projecting
bosses 112 mounted on the upper back corner of the side walls 114
of the outer compartment 32. Each boss 112 engages a track groove
116 in the side frames 12. The bosses 112 act both as pivots when
positioned at the base of the track groove and as guides when the
litter container 20 is displaced such that the bosses 112 are transported
up the grooves during the return operation.
When the cross bar 96 is depressed, the vertical link members 98
which are retained by straps 117 and restricted to vertical motion,
imparts the linear motion to the end of inter connecting link 104.
End link 106 has an intermediate connection to a pivot 118 on the
side frames 12 such that the end link acts as a lever arm to lift
the outer end of the litter container 20 when the cross bar 96 is
depressed. The litter container 20 swings upward as shown in phantom
in FIG. 1 whereupon the fecal matter retained on the bottom screen
48 slides across the screen and cover 90 and is deposited into the
collection box 24. To insure that the collection box is in place
when the cross bar mechanism 94 is actuated, a simple locking mechanism
120 as shown in FIG. 2 is provided. The collection box 24 has its
handle 26 connected to a false front 122 to match side frames 12
when the box is in place. Spacers 124 connect the false front 122
to the side wall 126 of box 24. The side wall 126 contacts a biased
plate 128 loosely connected at one end by bolt 130 and alignment
bolt 132 having a compression spring 133 to bias the plate 128 toward
the side frame 12. Neither bolt 130 nor bolt 132 interfere with
motion of the interconnecting link 104 as shown in FIG. 1. However,
bolted on the plate 128 is a machine screw 136 which is adjusted
and positioned to interfere with end link 106 when the box is removed
and the plate 128 is displaced toward the side frame 12. In this
manner depression of the cross bar 96 will be inhibited. The screw
and washer assembly 138 mounted on the false front 122 of the collection
box 24 provides a stop for inserting the collection box as the washer
assembly will in part contact the side frame 12 As shown in FIGS.
1 and 2.
The cross bar mechanism 94 operates in conjunction with a delay
mechanism 140 which comes into operation when it is desired to return
the litter box in it to its operable position. As shown in the schematic
views of FIGS. 8-10 when the litter box has been raised to the position
that results in discharge of the solid material collected by the
screen strainer 42 the granular material 36 shifts to the back
of the upper compartment 30 such that all of the liquid drains to
the bottom and back of the lower or outer compartment 32. When the
final upright position is reached as shown in FIG. 9 the back edge
142 of the lower or outer compartment 32 is positioned over the
collection box 24 the collected liquid waste pours into the collection
box. Concurrently, the top of the side walls 46 of the screen strainer
42 contacts the cross shaft 144 of the delay mechanism 140. This
contact forces the detent pin 86 to be released from the dimple
88 such that the screen strainer 44 will drop back against the inner
compartment 30 when the litter container begins to be returned to
its operational position. It is to be noted that the granular material
36 has shifted out of the way such that the screen strainer 42 can
reseat on the bottom of the inner compartment.
The delay mechanism 140 includes a pair of spaced cams mounted
on the ends of the cross shaft 144 with support wires having end
connectors 150 and 152 for connecting to the top of the cam 146
and the bottom part of the litter container 20. The cams 146 have
a grooved, arcuate edge 154 which allow the support wires 148 to
wrap and unwrap from the cams when the litter container 20 is raised
or lowered. The cams 146 as shown in FIG. 1 are connected to a
tension spring 156 connected at one end to a pin 158 in side frame
12 and mounted at its other end to a pin 160 on a crank member 162
connected to the shaft 144 by a nut and washer assembly 164. The
tension spring 156 compensates for the weight of the litter container
20 and contained granular material 36 such that operation of the
cross bar mechanism 94 requires minimal application of force. The
lever member 162 also includes an extension 166 connected to an
air cylinder 168 having a connection to the outside of one of the
side frames 12 by pin 170. The air cylinder 168 coacts with the
tension spring 156 to provide a smooth cushioned motion to the actuation
of the litter container, on its descent to the base pad 16.
When the litter container 20 is raised to the position shown in
FIG. 9 by actuation of the cross bar mechanism 94 the tension spring
causes the cam 146 to rotate maintaining tension on the support
wires 148. In the upright position a detent cam 172 has rotated
together with the support wire cams 146 such that a detent 174 engages
a notch 176 on a locking arm 178. The locking arm 178 shown in cross
section in FIG. 6 is pivotally mounted to one of the side frames
12 by a pin assembly that is constructed with a bolt 180 having
a thick shaft 181 and a thinner threaded end 182 for seating a washer
194 and wing nut 186 with spacers 188 and 190 allowing free pivot
of the locking arm 178. The locking arm 178 is biased by a tension
spring 192 connected to pin 194 on the side frame 12 and hole 196
on an extension 198 of the locking arm 178. When the support wires
148 are wrapped on the cams 146 when the container is lifted, detent
174 engages the notch 176 to lock the delay mechanism 140 in its
wrapped position. The litter container will shift its position when
the cross bar mechanism 94 is raised and the front end of the container
is dropped to the base pad as shown in phantom in FIG. 10. In this
tilted position the granular material 36 has spread evenly back
across the inner compartment 30 covering the bottom and the screen
strainer 42. With the litter container 20 in the rear raised position
shown in phantom in FIG. 10 the locking arm 178 can be automatically
released as the container 20 is pulled forward and down tracking
the bosses 112 up grooves 116. At the time the front edge of the
container 20 reaches the pad 16 one of the bosses 112 contacts
and displaces the tip 179 of locking arm 178 allowing the cams 146
to rotate and the wires 148 to unwrap such that the back end of
the litter container 20 gently seats onto the base pad 16 in the
position shown in FIG. 10.
Since the litter container 20 is only seated on the cross member
110 of the cross bar mechanism it can be removed from the housing
118 by disconnecting the looped wire on the end connectors for the
support wires 148 and displacing the extension 198 of the locking
arm 178 into a notch 200 in the side frame 12 clearing the track
groove 116 such that the litter container 20 can be lifted up and
out the housing 118. With the litter container removed the container
can be easily washed and the gravel replaced if desired. Generally,
the gravel is coated with a non-previous material such that even
after long use the gravel can be used, rinsed and replaced without
emitting offensive odors. As noted, the gravel can be periodically
sprayed with a odor mask and disinfectant while seated in the inner
or upper compartment of the container. The liquid rinse will simply
seep through the granular material 36 and be collected in the lower
compartment of the liquid container along with any liquid waste
from the household pets.
While in the foregoing, embodiments of the present invention have
been set forth in considerable detail for the purposes of making
a complete disclosure of the invention, it may be apparent to those
of skill in the art that numerous changes may be made in such detail
without departing from the spirit and principles of the invention. |