U.S. patent number RE36,847 [Application Number 08/997,879] was granted by the patent office on 2000-09-05 for automated self-cleaning litter box for cats.
This patent grant is currently assigned to Waters Research Company. Invention is credited to Michael A. Waters.
United States Patent |
RE36,847 |
Waters |
September 5, 2000 |
**Please see images for:
( Reexamination Certificate ) ** |
Automated self-cleaning litter box for cats
Abstract
An improved automated self-cleaning litter box for cats, of the
kind having a housing defining an upwardly open chamber for storage
of a supply of cat litter, accessible to a cat and having path
members on opposed side walls defining a comb path from one end of
the chamber to the other. A comb, normally stored at the comb
storage end of the chamber, is driven forward along the path to the
discharge end of the chamber and back to its original storage
position. As the comb traverses the chamber forwardly it engages
any clumps of waste in the litter and carries them to a disposal
receptacle at the discharge end of the chamber. The improvement
includes a sensor for sensing the presence of a cat in the litter
chamber; a photo electric sensor is preferred, but an infra red,
weight, or even an audible sensor can be used. A delay device
actuates the comb drive a predetermined time interval after the
sensor ceases to sense the presence of a cat in the litter chamber.
In the improved construction the comb path includes multi-perforate
track members on opposite sides of the litter chamber; those tracks
are engaged by rotatable drive wheels connected to the comb. The
comb drive includes a reversible electric motor, mounted on the
same carriage as the comb. A transparent, biodegradable receptacle
is used; alarms for a full receptacle and for an insufficient
litter supply are provided.
Inventors: |
Waters; Michael A. (Barrington
Hills, IL) |
Assignee: |
Waters Research Company (Elgin,
IL)
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Family
ID: |
23465382 |
Appl.
No.: |
08/997,879 |
Filed: |
December 24, 1997 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
371782 |
Jan 12, 1995 |
05477812 |
Dec 26, 1995 |
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Current U.S.
Class: |
119/163;
119/166 |
Current CPC
Class: |
A01K
1/011 (20130101); A01K 1/0114 (20130101) |
Current International
Class: |
A01K
1/01 (20060101); A01K 001/035 () |
Field of
Search: |
;119/161,163,164,165,166 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2069517 |
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Nov 1993 |
|
CA |
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0 154 540 |
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Apr 1985 |
|
EP |
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154540 |
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Sep 1985 |
|
EP |
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0 297 015 |
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Apr 1988 |
|
EP |
|
Primary Examiner: Manahan; Todd E.
Attorney, Agent or Firm: Dickstein Shapiro Morin &
Oshinsky LLP
Claims
I claim:
1. In an improved self-cleaning cat litter box including:
a pan-shaped housing having a bottom and two spaced side walls
connecting a storage end wall to a discharge end wall, the housing
defining an upwardly open litter chamber to be filled to a given
fill level with cat litter;
a comb path extending from the storage end wall to the discharge
end wall;
a comb extending between the side walls; and
a comb drive for driving the comb along the comb path from a
storage position adjacent the storage end wall to a discharge
position adjacent the discharge end wall and back to the storage
position, the comb projecting down into the litter chamber to a
level below the fill level and near the housing bottom while the
comb moves toward the discharge end wall so that the comb engages
any clumps in the litter and carries such clumps to the discharge
position;
the improvement comprising:
a cat exit sensor for sensing exit of a cat from the litter
chamber;
delay means, connected to the cat exit sensor and to the comb
drive, for actuating the comb drive to drive the comb from the
storage position to the discharge position and back to the storage
position at a predetermined time subsequent to sensing of exit of a
cat from the litter chamber and
a litter level sensor for sensing an insufficient quantity of
litter in the litter chamber, below the given fill level.
2. An improved cat litter box according to claim 1, and further
comprising:
a waste receptacle located outside of the litter chamber adjacent
to the discharge end wall; and
deflection means, on the comb path, for deflecting the comb to
deposit clumps carried by the comb into the waste receptacle.
3. An improved cat litter box according to claim 2 in which:
the waste receptacle includes a base pan and a cover hinged to the
base pan; and
the deflection means raises the cover of the waste receptacle to
enable deposit of clumps in the base pan, of the waste
receptacle.
4. An improved cat litter box according to claim 2 in which the
waste receptacle comprises:
a base pan for receiving and storing cat waste from the litter
box;
a cover hinged to and normally covering the base pan; and
guide means, on the cover, engageable by the deflection means of
the litter box to raise the cover to an open position.
5. An improved cat litter box according to claim 1 in which the cat
exit sensor comprises:
radiation source, mounted adjacent one side of the litter chamber,
the radiation source producing a beam that projects across the
litter chamber above the fill level; and
a detector mounted adjacent the other side of the litter chamber in
position to intercept the beam from the radiation source.
6. An improved cat litter box according to claim 5 in which:
the radiation source is a light source and the beam is a light
beam;
the detector is a photodetector; and
the light source and the photodetector are mounted on opposite side
walls of the litter chamber.
7. An improved cat litter box according to claim 1 in which the
litter level sensor comprises:
a radiation source, mounted adjacent one side of the litter
chamber, the radiation source producing a beam that projects across
the liter chamber below the fill level; and
a detector mounted adjacent the other side of the litter chamber in
position to intercept the beam from the radiation source.
8. In an improved self-cleaning cat litter box including:
a pan-shaped housing having a bottom and two spaced side walls
connecting a storage end wall to a discharge end wall, the housing
defining an upwardly open litter chamber to be filled to a given
fill level with cat litter;
a comb path extending from the storage end wall to the discharge
end wall;
a comb extending between the side walls; and
a comb drive for driving the comb along the comb path from a
storage position adjacent the storage end wall to a discharge
position adjacent the discharge end wall and back to the storage
position, the comb projecting down into the litter chamber to a
level below the fill level and near the housing bottom while the
comb moves toward the discharge end wall so that the comb engages
any clumps in the litter and carries such clumps to the discharge
position;
the improved construction comprising:
a track member, defining the comb path, mounted to one side wall
above the fill level;
a carriage supporting the comb;
a guide wheel mounted on the carriage and engaging the track
member;
and a reversible drive motor, comprising a part of the comb drive,
mounted on the carriage.
9. An improved cat litter box according to claim 8, in which the
carriage includes a comb shaft extending across the litter chamber
from one side wall to the other, and further comprising:
a second track member mounted on the other side wall above the fill
level; and
a second guide wheel mounted on the carriage and engaging the
second track member.
10. An improved cat litter box-according to claim 9 in which:
each track member has a multiplicity of equally spaced perforations
along the track;
and further comprising:
a first drive wheel mounted on one end of the comb shaft and having
a plurality of radial drive pins engageable in the perforations of
the first track member; and
a second drive wheel mounted on the other end of the comb shaft and
having a plurality of radial drive pins engageable in the
perforations of the second track member.
11. An improved cat litter box according to claim 10 in which the
drive means comprises a gear train connecting the motor to the comb
shaft to rotate the comb shaft.
12. An improved cat litter box according to claim 11 in which each
track member includes an upwardly inclined extension at its
opposite ends so that the comb is directed upwardly above the fill
level at both ends of the litter chamber.
13. An improved cat litter box according to claim 8 and further
comprising:
a cat exit sensor for sensing exit of a cat from the litter
chamber; and
delay means, connected to the sensor and to the reversible motor,
for actuating the comb drive motor to drive the comb from the
storage position to the discharge position at a predetermined time
interval subsequent to sensing of exit of a cat from the litter
chamber.
14. An improved cat litter box according to claim 13, and further
comprising:
a waste receptacle located outside of the litter chamber adjacent
to the discharge end wall; and
deflection means, on the comb path, for deflecting the comb to
deposit clumps carried by the comb into the waste receptacle.
15. An improved cat litter box according to claim 14 in which:
the waste receptacle includes a base pan and a cover hinged to the
base pan; and
the deflection means raises the cover of the waste receptacle to
enable deposit of clumps in the base pan of the waste
receptacle.
16. An improved cat litter box according to claim 13 in which the
cat exit sensor comprises:
a radiation source, mounted adjacent one side of the litter
chamber, the radiation source producing a beam that projects across
the litter chamber above the fill level; and
a detector mounted adjacent the other side of the litter chamber in
position to intercept the beam from the radiation source.
17. An improved cat litter box according to claim 16 in which:
the radiation source is a light source and the beam is a light
beam;
the detector is a photodetector; and
the light source and the photodetector are mounted on opposite side
walls of the litter chamber.
18. An improved cat litter box according to claim 8 and further
comprising:
a litter level sensor for sensing an insufficient quantity of
litter in the litter chamber, below the given fill level.
19. An improved cat litter box according to claim 18 in which the
litter level sensor comprises:
a radiation source mounted adjacent one side of the litter chamber,
the radiation source producing a beam that projects across the
latter chamber below the fill level; and
a detector mounted adjacent the other side of the litter chamber in
position to intercept the beam from the radiation source.
20. In an improved self-cleaning cat litter box including:
a pan-shaped housing having a bottom and two spaced side walls
connecting a storage end wall to a discharge end wall, the housing
defining an upwardly open litter chamber to be filled to a given
fill level with cat litter;
a comb path extending from the storage end wall to the discharge
end wall;
a comb extending between the side walls;
a comb drive for driving the comb along the comb path from a
storage position adjacent the storage end wall to a discharge
position adjacent the discharge end wall and back to the storage
position, the comb projecting down into the litter chamber to a
level below the fill level and near the housing bottom while the
comb moves toward the discharge end wall so that the comb engages
any waste clumps in the litter and carries such waste clumps to the
discharge position; and
a waste receptacle locate outside of the litter chamber adjacent to
the discharge end wall, for receiving waste carried to the
discharge end of the litter box by the comb;
the improved construction comprising:
a waste receptacle sensor for sensing filling of the waste
receptacle;
an excess waste alarm actuated by the waste receptacle sensor;
a litter level sensor for sensing an insufficient quantity of
litter in the litter chamber, below the given fill level; and
an insufficient litter alarm actuated by the litter level
sensor.
21. An improved cat litter box according to claim 20 in which the
waste receptacle sensor comprises:
a radiation source, mounted on an extension of one side wall beyond
the discharge end wall, the radiation source producing a beam that
projects across the waste receptacle; and
a detector, mounted on an extension of the other side wall beyond
the discharge end wall, positioned to intercept the beam from the
radiation source.
22. An improved cat litter box according to claim 20 in which the
litter level sensor comprises:
a radiation source, mounted adjacent one side of the litter
chamber, the radiation source producing a beam that projects across
the litter chamber below the fill level; and
a detector mounted adjacent the other side of the litter chamber in
position to intercept the beam from the radiation source.
.Iadd.
23. A self-cleaning cat litter box comprising:
a pan-shaped housing having two opposed sidewalls, the housing
defining an upwardly open litter chamber to be filled to a given
fill level with cat litter;
a comb extending between the two opposed sidewalls;
comb drive means for driving the comb between a storage position
and a discharge position, the comb projecting down into the litter
chamber to a level below the fill level while the comb moves toward
the discharge position so that the comb engages clumps in the
litter and moves such clumps toward the discharge position; and
litter supply sensor means for sensing an insufficient supply of
litter in the litter chamber..Iaddend..Iadd.24. A self-cleaning cat
litter box comprising:
a pan-shaped housing defining an upwardly open litter chamber to be
filled to a given fill level with cat litter;
moving means disposed in the pan-shaped housing;
a carriage supporting the moving means; and
drive means for driving the moving means between a storage position
and a discharge position, the moving means projecting down into the
litter chamber to a level below the fill level while the moving
means moves toward the discharge position so that the moving means
engages clumps in the litter and moves such clumps toward the
discharge position;
said drive means including motor means mounted on the carriage for
driving the moving means between the storage position and the
discharge
position..Iaddend..Iadd.25. The litter box of claim 24 wherein the
motor
means includes a reversible drive motor..Iaddend..Iadd.26. A
self-cleaning cat litter box comprising:
a pan-shaped housing defining an upwardly open litter chamber to be
filled
to a given fill level with cat litter;
a waste receptacle located outside the litter chamber;
a comb disposed in the litter chamber;
comb drive means for driving the comb between a storage position
and a discharge position, the comb projecting down into the litter
chamber to a level below the fill level while the comb moves toward
the discharge position so that the comb engages clumps in the
litter and moves such clumps toward the discharge position; and
waste level sensor means for sensing when waste has reached a
predetermined level in the receptacle, and wherein said waste level
sensor means is arranged to perform a sensing operation internally
of said receptacle..Iaddend..Iadd.27. A self-cleaning cat litter
box comprising:
a pan-shaped housing defining an upwardly open litter chamber to be
filled to a given fill level with cat litter;
a comb disposed in the litter chamber;
comb drive means for driving the comb between a storage position
and a discharge position, the comb projecting down into the litter
chamber to a level below the fill level while the comb moves toward
the discharge position so that the comb engages clumps in the
litter and moves such clumps toward the discharge position; and
mode selector means for selecting between at least a manual
operation mode for said comb drive means and an automatic operation
mode for said comb drive means..Iaddend..Iadd.28. A self-cleaning
cat litter box comprising:
a pan-shaped housing having two opposed sidewalls, the housing
defining an upwardly open litter chamber to be filled to a given
fill level with cat litter;
a comb drive coupled to the housing;
a comb extending between the two opposed sidewalls and being
coupled to the comb drive and movable between a storage position
and a discharge position, the comb projecting down into the litter
chamber to a level below the fill level so that the comb engages
clumps in the litter and carries such clumps to the discharge
position; and
a litter supply sensor coupled to the housing..Iaddend..Iadd.29.
The litter box of claim 28 wherein the litter supply sensor is
disposed to sense an insufficient supply of litter in the litter
chamber..Iaddend..Iadd.30. The litter box of claim 29 wherein the
litter supply sensor includes a radiation source mounted in the
litter chamber and disposed to produce a beam that projects across
the litter chamber and a detector mounted in the litter chamber to
intercept the beam from the radiation
source..Iaddend..Iadd.31. A self-cleaning cat litter box
comprising:
a pan-shaped housing defining an upwardly open litter chamber to be
filled to a given fill level with cat litter;
a comb drive coupled to the housing;
a comb extending between two opposed sidewalls and being coupled to
the comb drive and movable between a storage position and a
discharge position, the comb projecting down into the litter
chamber to a level below the fill level so that the comb engages
clumps in the litter and moves such clumps toward the discharge
position; and
a comb supporting carriage, said comb drive including a drive motor
mounted on the carriage..Iaddend..Iadd.32. The litter box of claim
31 wherein the
drive motor is reversible..Iaddend..Iadd.33. A self-cleaning cat
litter box comprising:
a pan-shaped housing defining an upwardly open litter chamber to be
filled to a given fill level with cat litter;
a comb drive coupled to the housing;
a comb extending between two opposed sidewalls and being coupled to
the comb drive and movable between a storage position and a
discharge position, the comb projecting down into the litter
chamber to a level below the fill level so that the comb engages
clumps in the litter and moves such clumps toward the discharge
position; and
a mode selector switch operatively connected to said comb drive,
the switch being moveable between a manual operation position
wherein an operator causes the comb to move toward the discharge
position and an automatic operation position wherein the comb moves
toward the discharge position automatically upon the occurrence of
a predetermined event..Iaddend..Iadd.34. A self-cleaning cat litter
box comprising:
a pan-shaped housing defining an upwardly open litter chamber to be
filled to a given fill level with cat litter;
a waste receptacle located outside the litter chamber;
a comb disposed in the litter chamber;
comb drive means for driving the comb between a storage position
and a discharge position, the comb projecting down into the litter
chamber to a level below the fill level while the comb moves toward
the discharge position so that the comb engages clumps in the
litter and moves such clumps toward the discharge position; and
a waste level sensor coupled to the litter chamber, wherein said
waste level sensor is arranged to perform a sensing operation
internally of said receptacle..Iaddend..Iadd.35. The litter box of
claim 34 further including an alarm coupled to the waste level
sensor, the alarm being activated when the waste level sensor
determines that waste in the waste receptacle has reached a
predetermined height..Iaddend..Iadd.36. A self-cleaning cat litter
box comprising:
a pan-shaped housing having two opposed sidewalls, the housing
defining an upwardly open litter chamber to be filled to a given
fill level with cat litter;
a comb extending between the two opposed sidewalls; and
comb drive means for driving the comb between a storage position
and a discharge position, the comb projecting down into the litter
chamber to a level below the fill level while the comb moves toward
the discharge position so that the comb engages clumps in the
litter and moves such clumps toward the discharge position, the
comb being positioned above the fill level in the storage position
and the discharge
position..Iaddend..Iadd.37. A self-cleaning cat litter box
comprising:
a housing defining an upwardly open litter chamber to be filled to
a given fill level with cat litter;
a comb drive coupled to the housing;
a comb extending between the two opposed sidewalls and being
coupled to the comb drive and movable between a storage position
and a discharge position, the comb projecting down into the litter
chamber to a level below the fill level so that the comb engages
clumps in the litter and moves such clumps toward the discharge
position and being positioned above
the fill level in the storage position..Iaddend..Iadd.38. A
self-cleaning cat litter box comprising:
a pan-shaped housing defining an upwardly open litter chamber to be
filled to a given fill level with cat litter;
a waste receptacle located outside the litter chamber;
a comb disposed in the litter chamber;
comb drive means for driving the comb between a storage position
and a discharge position, the comb projecting down into the litter
chamber to a level below the fill level while the comb moves toward
the discharge position so that the comb engages clumps in the
litter and moves such clumps toward the discharge position; and
waste level sensor means for sensing when waste has reached a
predetermined level in the receptacle; and
wherein said waste level sensor means includes a source of
radiation..Iaddend..Iadd.39. The litter box of claim 38 wherein
said waste level sensor means further includes a detector for
generating a signal in
response to radiation from said source..Iaddend..Iadd.40. The
litter box of claim 39 wherein said waste receptacle includes first
and second walls, said radiation source being located on said first
wall, said detector being located on said second wall, such that
waste at said predetermined level blocks radiation transmission
between said radiation source and said detector..Iaddend..Iadd.41.
The litter box of claim 27 further comprising a sensor system for
determining whether a cat is in the litter
chamber..Iaddend..Iadd.42. The litter box of claim 41 wherein said
sensor system includes a source of radiation and a radiation
detector..Iaddend..Iadd.43. A self-cleaning cat litter box
comprising:
a pan-shaped housing defining an upwardly open litter chamber to be
filled to a given fill level with cat litter;
a comb drive coupled to the housing;
a comb extending between two opposed sidewalls and being coupled to
the comb drive and movable between a storage position and a
discharge position, the comb projecting down into the litter
chamber to a level below the fill level so that the comb engages
clumps in the litter and moves such clumps toward the discharge
position; and
a mode selector switch, the switch being moveable between a manual
operation position wherein an operator causes the comb to move
toward the discharge position and an automatic operation position
wherein the comb moves toward the discharge position automatically
upon the occurrence of a predetermined event; and
wherein said comb drive is operated on a cyclical basis when said
mode selector switch is in said manual operation
position..Iaddend..Iadd.44. A self-cleaning cat litter box
comprising:
a pan-shaped housing defining an upwardly open litter chamber to be
filled to a given fill level with cat litter;
a waste receptacle located outside the litter chamber;
a comb disposed in the litter chamber;
comb drive means for driving the comb between a storage position
and a discharge position, the comb projecting down into the litter
chamber to a level below the fill level while the comb moves toward
the discharge position so that the comb engages clumps in the
litter and moves such clumps toward the discharge position; and
a waste level sensor coupled to the litter chamber; and
wherein said cat litter box further includes an alarm coupled to
the waste level sensor, the alarm being activated when the waste
level sensor determines that waste in the waste receptacle has
reached a predetermined level; and
wherein said waste level sensor includes a source of radiation and
a radiation detector..Iaddend..Iadd.45. The litter box of claim 44
wherein said source and said detector are located such that waste
at said predetermined level is between said source and said
detector..Iaddend..Iadd.46. A self-cleaning cat litter box
comprising:
a housing defining a litter chamber to be filled to a fill level
with cat litter, said housing having first and second ends, said
litter chamber being located between said first and second ends;
and
a device for engaging clumps in the litter, said device being
coupled to the housing, said device being movable between a storage
position and a discharge position, said storage position being
located at said first end of said housing, said discharge position
being located at said second end of said housing, and wherein said
device projects into said litter chamber to a level below the fill
level so that the device engages clumps in the litter and moves
such clumps toward the discharge position, and wherein said device
is positioned above the fill level in said storage
position..Iaddend..Iadd.47. The litter box of claim 46 wherein said
device includes tines arranged to move through the cat litter in
said litter chamber, said tines being located above the fill level
when said device is in said storage position..Iaddend..Iadd.48. The
litter box of claim 47 further comprising a track extension for
removing said tines from the cat litter as said device moves toward
said storage position..Iaddend.
Description
BACKGROUND OF THE INVENTION
Cats, which are among the most popular types of domestic pets, are
usually trained to use a litter box for elimination of both liquid
and solid wastes. A cat litter box is normally made of plastic or
like material so that a cat's urine will not leak through the box.
Other types of cat litter box have been proposed, as in the
construction described in Rockaitis U.S. Pat. No. 5,249,549, in
which the litter box is made of a material that absorbs liquid but
does not permit it to leach through to the exterior of the box. The
litter used in boxes of this kind may be one of any number of
particulate litter materials that absorb moisture from the waste of
the cat and that may also suppress odor from cat wastes. Some forms
of cat litter form clumps when wet. Usually, a cat will bury its
solid waste in the litter material in the box.
Most cat owners take appropriate action to discard the litter from
cat litter box after an appreciable period of time, often several
days. On the other hand, even before the litter has been thoroughly
saturated with wastes from the cat or cats that use it, a cat may
be inclined to push some of the litter out of the box, particularly
if the odor is strong. In any event, the person using a cat litter
box, usually the owner of the cat or cats, may find the task of
emptying the cat litter to be personally obnoxious. Thus, a number
of prior art devices have been proposed for cleaning cat litter
boxes; devices of this kind are disclosed in U.S. Pat. No.
4,096,827, No. 4,117,804, No. 4,190,525, No. 4,325,325, No.
4,325,822, and No. 5,226,388. Perhaps the best of these devices is
disclosed in Carlisi U.S. Pat. No. 5,048,465.
The self-cleaning cat litter box disclosed in the Carlisi patent
utilizes a rake or comb that is normally maintained in a storage
position at one end of the litter chamber. This comb is moved
through the litter, periodically, from the rake storage end of the
chamber to the opposite end, which constitutes a discharge end for
the chamber. At the discharge end of the chamber the rake moves up
out of the litter and discharges any clumps collected by the comb
into a disposal receptacle. The present invention provides
effective improvement for the rake drive of the Carlisi device so
that movement of the comb or rake through the litter can be made
responsive to entry and exit of the cat from the litter box. Cats
are no more constant in their elimination habits than human beings;
periodic cleaning may be inappropriate. The invention also provides
for improvements in the disposal receptacle, which may also serve
as a container for a new litter supply. Alarms are also provided
for an insufficient litter supply and a full disposal
receptacle.
SUMMARY OF THE INVENTION
It is a principal object of the present invention, therefore, to
provide a new and improved drive for a rake or comb employed to
remove litter from a cat litter box, a drive that is directly
responsive to the exit of a cat from the litter box.
Another object of the invention is to provide a new and improved
drive for a self-cleaning cat litter box that is capable of
remaining in, operation for extended periods of time without
attention from the cat owner and that does not operate on a
periodical basis so that there is no substantial possibility that
the comb mechanism will carry out a cleaning operation while a cat
is present in the litter box.
Another object of the present invention is to provide a new and
improved drive for an automated self-cleaning cat litter box that
is simple and economical in construction and that can afford an
extended operating life, requiring little or no attention apart
from battery replacement.
Further objects of the invention are to provide an improved waste
receptacle, an alarm signalling an inadequate litter supply in the
litter box, and an alarm signalling that the waste receptacle is
full.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1, 2 and 3 are perspective views of an automated
self-cleaning litter box for use by a cat, constructed in
accordance with a preferred embodiment of the invention, showing
the litter box at three distinct stages of operation;
FIG. 4 is a transverse sectional view taken approximately along
line 5--5 in FIG. 2;
FIG. 5 is a block diagram of the drive and control for the litter
box of FIGS. 1-3;
FIG. 6 is a flow chart for operation of the cat litter box of FIGS.
1-5;
FIG. 7 is a detailed flow chart illustrating optional modes of
operation for the controls of the automated self-cleaning cat
litter box;
FIG. 8 is a detail view illustrating a litter level sensor; and
FIG. 9 is a detail view showing a full-receptacle sensor
system.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS. 1-3 illustrate successive positions for the operating
mechanism of la cat litter box 20 that affords automated
self-cleaning operation. Litter box 20 comprises a pan-shaped
housing 21 having a near side wall 22, a far side wall 23, a
discharge end wall 24 joining walls 22 and 23 at one end of the
litter box and a comb storage end wall 25 connecting walls 22 and
23 at the other end of litter box 20. The bottom of litter box 20
is identified by reference numeral 26 and the fill level to which
box 20 is usually filled with cat litter is shown by phantom line
38. Thus, in litter box 20 there is a discharge end 28 at one end
of the litter box and a comb storage end 29 at the opposite end of
the litter box. Litter level line 38 may be afforded by a
continuous or interrupted ridge in the interior of housing 21, as
discussed in regard to FIG. 8. All of the members 22-26 are
preferably formed in a molding operation that produces the complete
housing 21.
An elongated near Side track or path member 32 extends along the
top of the near side wall 22 of housing 21, FIGS. 1-4. Track member
32 includes a multiplicity of equally spaced apertures 32A.
Apertures 32A extend through an inclined portion 34 of rack 32 at
the discharge end 28 of litter box 20; they also extend through a
more steeply inclined portion 36 of rack 32 at the comb storage end
29 of the litter box. This track construction is repeated on the
opposite side of housing 21. Thus, an elongated track member 33
projects horizontally from the vertical side wall 23. Track member
33 includes a multiplicity of equally spaced apertures or
perforations 33A. The pattern of apertures extends along an
inclined portion 35 of track member 33 at the discharge end 28 of
litter box 20. It also extends along a more steeply inclined
portion 37 of track 33 located at the comb discharge end 29 of
litter box 20.
A comb shaft 41 extends across litter box 20 between its two side
tracks 32 and 33. In FIG. 1 shaft 41 is located at the comb storage
end 29 of the litter box. In FIG. 2 shaft 41 is positioned at about
the middle of the litter box. In FIG. 3 shaft 41 is shown near the
end of its movement at the discharge end 28 of litter box 20. There
are four hangers 42 journalled on and depending from shaft 41;
three of these hangers appear in FIGS. 1-3 and the fourth can be
seen in FIG. 4. A comb or rake 43 is suspended from hangers 42.
Comb 43 has a multiplicity of tines 44. When comb 43 is in its
storage position, as shown in FIG. 1, tines 44 are elevated above
the litter fill level 38. When rack 43 is moving across litter box
20, as indicated by arrow A in FIG. 2, the lower ends of the tines
44 project down into the litter in box 20, close to the bottom 26
of the box. See FIG. 4. At the discharge end of litter box 20, the
tines 44 of comb 43 again move upwardly out of the litter.
A first main guide wheel 52 is affixed to the near end of shaft 41,
as seen in FIGS. 1-3. Guide wheel 52 includes a plurality of
radially projecting guide pins or teeth 52A engageable in the
apertures 32A of track member 32 and its extensions 34 and 36. At
the other end of shaft 41 there is a similar main guide wheel 53.
The radial projections 53A on guide wheel 53 are engageable in the
apertures 33A of track member 33 and its extensions 35 and 37.
Guide wheels 52 and 53 cause the ends of shaft 41 to move along
tracks 32 and 33, based on rotation of shaft 41, from the storage
position of FIG. 1 through the intermediate position of FIG. 2 to
the discharge position of FIG. 3 and back to the storage position,
FIG. 1.
The improved self-cleaning cat litter box 20, FIGS. 1-3, includes a
comb drive that comprises a reversible electric motor 55 mounted on
and connected in driving relationship to the shaft 41 that supports
comb 43; the final gear 57 of the gear train that connects motor 55
to shaft 41 is the only gear that appears in the drawings, FIGS.
1-3. In the construction illustrated in the drawings, motor 55 is
energized from batteries contained in a battery case 56. Motor 55
and the gear train represented by gear 57, as well as battery case
56, are supported by shaft 41; in conjunction with the shaft, they
constitute the carriage for the comb 43 in litter box 20. A
reversing switch 58 is mounted on and electrically connected to
motor 55. A lever 59 is mechanically connected to reversing switch
58. Lever 59 has a limited pivotal movement, from the position
shown in FIG. 1 to the position illustrated in FIG. 2. A first
switch actuation pin 61 is located adjacent the comb storage end 29
of litter box 20. A similar fixed switch actuation pin 62 is
positioned at the other end, the discharge end 28, of litter box
20.
In addition to the main guide wheels 52 and 53 referred to above,
the drive and guidance system of litter box 20 includes two
auxiliary guide wheels 64 and 65, located on the near and far sides
of the litter box, respectively, as seen in the drawings. Auxiliary
guide wheel 64 is mounted at the end of a lever 66 that projects
from one of the hangers 42 used to suspend comb 43 from shaft 41.
Auxiliary guide wheel 64 rides along track 32 throughout the length
of that track, including its upwardly inclined end sections 34 and
36. Similarly, the auxiliary guide wheel 65 is mounted on a lever
67 and engages the other track member 33 and its extensions 35 and
37. See FIG. 4.
As shown in FIGS. 1-3, the improved automated self-cleaning cat
litter box 20 is provided with a waste receptacle 68 positioned
immediately adjacent the discharge end 28 of the litter box.
Receptacle 68 has a hinged lid 69. Waste receptacle 68 and its lid
69 are preferably formed of a biodegradable material. Moreover,
receptacle 68 should be transparent; alternatively, lid 69 may be
transparent or, of course, both may be transparent enough to permit
the user to visually check the level of waste and litter in the
receptacle. Lid 69 is engaged by a pin 75 on a lid lift lever 73
that is pivotally secured to a vertical extension 23A of side
wall 23. The pivotal connection is indicated at 74. There need be
no comparable lid lift mechanism 73-75 at the near side of the
machine, though one could be provided if motor 55 and battery case
56 were mounted closer to the center of the litter box. In FIGS. 1
and 2 waste clumps 71 are indicated in the litter chamber; similar
clumps 72 are shown, in FIGS. 1-3, as being already deposited in
receptacle 68.
Waste receptacle 68 may be formed of plastic or other suitable
material. The lid 69 for receptacle 68 is hinged to the receptacle
as indicated at 76. A hinge of the so-called "piano" type may be
used, but other hinge structures are acceptable. Lid 69 may also be
formed of plastic. On the other hand, receptacle 68 and its lid 69
may be fabricated of other appropriate material. Preferably,
receptacle 68 initially serves as a container for clean litter so
that, once the receptacle is ready to be discarded, it can simply
be removed and a new receptacle put in place after emptying clean
litter from the new waste receptacle into the chamber afforded by
housing 21.
The improved automated self-cleaning litter box 20 further
comprises a sensor utilized to sense the exit of a cat from the
litter chamber afforded by housing 21. In the embodiment of FIGS.
1-3 there are two such sensors 82 and 84, both mounted on wall 23
above the fill line 38 for litter. Devices 82 and 84 may comprise
conventional photo detectors, each receiving a light beam from a
source not shown in FIGS. 1-2. FIG. 4 shows an appropriate light
source 86 mounted on wall 22 above fill level 38. Photo detector
82, FIG. 4, is also located above fill level 38. A single light
source located centrally along the length of wall 22 can be used or
there may be two such light sources 86, one for each of the photo
detectors 82 or 84.
A block diagram for the operating circuit of the improved automated
self-cleaning litter box 20 is presented in FIG. 5. As shown
therein, motor 55 is energized from battery 56 through a
pre-programmed micro-processor control 96. Micro control 96
receives input signals from cat sensors 82 and 84. Additional
inputs to control 96 may be supplied by a mode select switch 91, a
motor stall sensor 92, a battery voltage sensor 93, and a home
position sensor 94 for comb 43. Limit switches 95 may be provided
for the comb at the storage end 28 of litter box 20 and at the
discharge end 29 of the litter box. One or more buzzers or other
alarm devices 97 are included in the circuit so that the cat owner
can be signalled when the litter box is functional or when other
conditions occur, such as an insufficient litter supply in box 20
or a full waste receptacle 68. Circuit components 91-93 and buzzer
97 may all be packaged in the same housing with motor 55. Sensor 94
and limit switches 95 can be incorporated in litter box 20 in
appropriate positions as desired.
In considering operation of the improved automated self-cleaning
litter box 20 of FIGS. 1-4, the best starting point is FIG. 1,
which shows the litter box in its normal condition, applicable most
of the time. Comb 43 is located at the comb storage end 29 of
litter box 20. Comb shaft 41 is elevated, guide wheels 52 and 53
having ridden up the extensions 36 and 37 of tracks 32 and 33.
Switch 58 and lever 59 have engaged pin 61; motor 55 is shut off,
but is set for forward movement. Housing 21 is filled with litter,
approximately to level 38. Photo detectors 82 and 84 receive light
beams from sources 86 on the near wall 22 of the litter box (see
FIG. 4). With no cat present in the litter box, reception of the
light beams by photo detectors 82 and 84 is unimpeded. All other
mechanisms are in the positions shown. Lid 69 is closed over
receptacle 68. The receptacle lid is engaged by pin 75 at the end
of lever 73 but remains closed because the lid opening lever 73 is
inactive.
At this juncture, it may be assumed that a cat (not illustrated)
enters litter box 20 for the purpose of elimination of either
liquid or solid waste. With some kinds of litter, the urine from
the cat creates a clump in the litter with which the bottom portion
of housing 21 is filled. Of course, for solid elimination, the
clump is formed by the waste itself. In either instance, the cat is
likely to bury the waste or to cover it with other litter. This is
almost invariably true with respect to solid waste. Thus, clumps 71
are produced by the cat, and those clumps are located at some level
in the litter above the bottom 26 of litter box 20. It is assumed
that the box has previously been used and that previously deposited
waste clumps 72 are already present in the waste receptacle 68.
While the cat is present in the litter box, the light beam to at
least one of the photo detectors 82 and 84 is cut off. Usually,
both light beams are blocked. However, this does not initiate a
self-cleaning operation in litter box 20. Subsequently, when the
Cat leaves the litter box the light beam or beams again impinge
upon the photo detectors. Accordingly, an output signal from one or
both cat sensors is supplied to micro control 96 (FIG. 5). At this
point, however, there still is no actuation of a self-cleaning
operation in box 20 by comb 43. The reason for the delay is that
the cat might return to the litter box, deciding that its
elimination activities have not been completed. In these
circumstances, the light beams to one or both of the photo
detectors 82 and 84 are again cut off and the preset delay interval
for actuation of a self-cleaning operation is not completed.
Ultimately, the cat leaves litter box 20 for an interval long
enough to exceed the preset time delay that is set into micro
control 96. That time interval is subject to substantial variation;
a range of two to seven minutes is usually desirable. The
self-cleaning operation carried out by comb 43 should not be
initiated while the cat is in the immediate vicinity because it is
undesirable to cause the cat to have reason to be afraid of the
litter box.
After the cat has left litter box 20 for a time exceeding the
preset delay interval in micro control 96, FIG. 5, motor 55 is
energized from battery 56 through microcontrol 96. As a
consequence, gear 57 and shaft 41 are rotated in the direction of
the arrow B in FIG. 1. The initial movement of the comb carriage
comprising shaft 41, motor 55, and battery housing 56 is downwardly
along track extensions 36 and 37. In the course of this downward
movement of comb 43, its tines 44 are pushed downwardly into the
litter in the bottom portion of housing 21, well below fill line
38. The bottoms of the tines, when this movement is completed, are
quite close to the bottom 26 of the litter box housing but
preferably don't quite engage the bottom of the housing; see FIG.
4.
Motor 55 remains energized and shaft 41 continues to rotate in the
direction of arrow B. As a consequence, comb 43 is driven across
the litter chamber defined by the housing 21 of box 20, from
storage end 29 to discharge end 28, as indicated in FIG. 2 by arrow
A. Reference may also be made to FIG. 4, where the position of the
comb and its tines 44 are illustrated. As the comb moves across the
litter box, in the direction of arrow A, tines 44 engage any clumps
71 present in the litter, whether generated by the elimination of
liquid or solid wastes by the cat. Comb 43 carries those clumps
toward the discharge position 28 at the far end of box 20, the
right hand end of the litter box as seen in FIGS. 1 and 2. Comb 43
remains in a substantially erect position as shown in FIG. 2. It is
prevented from rotating in the direction of arrow B by the
engagement of auxiliary guide wheels 64 and 65 with tacks 32 and 33
respectively. The forward motion of the comb in the direction of
arrow A is effected by rotation of shaft 41 in the direction of
arrow B and the engagement of guide wheels 52 and 53 and their pins
52A and 53A in the apertures 32A and 33A of the two tracks 32 and
33 that define the comb path.
Ultimately, comb 48 advances to a position where its main guide
wheels 52 and 53 reach the upwardly inclined extension portions 34
and 35 of tracks 32 and 33, respectively. Motor 55 is still
energized; as a consequence, the carriage comprising shaft 41 moves
up the ramps or track extensions 34 and 35 to the position shown in
FIG. 3. During this upward movement of comb 43, lever 73 is engaged
by the comb carriage and is pivoted upwardly from the original
position shown in FIGS. 1 and 2 to the elevated position shown in
FIG. 3. As a consequence, due to the engagement of pin 75 with a
slot or like guide 77 in receptacle cover 69, cover 69 is opened,
moving to the position shown in FIG. 3. When comb 43 reaches the
discharge position shown in FIG. 3, the additional clumps 71 are
discharged into receptacle 68 to join clumps 72 already present
there.
When Comb 43 reaches the position of FIG. 3, it actuates one of the
limit switches 95 of FIG. 5; the limit switch is not shown in the
drawing and can be positioned to be actuated by any part of the
comb or its carriage. The resulting output signal to micro control
96 (FIG. 5) reverses motor 55 and the motor starts to rotate shaft
41 in the direction of arrow C, FIG. 3. Accordingly, comb 43 is
driven, by motor 55, back to its storage position illustrated in
FIG. 1. In the process, discharge lever 73 is disengaged and drops
back down to its original position, so that lid 69 on receptacle 68
again closes. The waste from litter box 20 is now totally enclosed
in waste receptacle 68.
When comb 43 has finished its movement back to a point closely
adjacent to storage end wall 25, its two main guide wheels 52 and
53 encounter the steeply inclined upward extensions 36 and 37 of
tracks 32 and 33. Motor 55 remains energized and pulls comb 43 and
its shaft 41 up to the position shown in FIG. 1. When the comb
reaches that position, switch 58 is actuated by pin 61 and sets
motor 55 for subsequent operation in the forward direction. When
comb 43 reaches the end of its travel, at the position shown in
FIG. 1, another of the comb limit switches 95 (FIG. 5) is actuated
and a signal is supplied to micro control 96 to shut off the motor.
A "home" sensor 94 may be provided for the same purpose. Usually,
it is desirable to have both a home sensor 94 and a limit switch 95
(see FIG. 5) to actuate the micro control 96 and make sure that
motor 55 is shut off with comb 43 at the storage position 29 shown
in FIG. 1.
FIG. 6 is a flow chart illustrating a subroutine programmed into
micro control 96 (FIG. 5) for a self-cleaning operation in the
improved litter box 20. The flow chart starts with a comb litter
command 101 supplied to the micro control. As a consequence, a set
direction and start command is supplied to motor 55 in step 102 of
the subroutine. In the next step 103, if motor 55 is stalled, that
condition is sensed and there is an output command to subsequent
step 105 to reverse the direction of the motor. Ordinarily,
however, the motor will not be stalled and the next step is to
determine whether the comb is at its end of travel. If not, there
is a feedback command to stage 103. If comb 43 is located at the
discharge end of its travel, the output from stage 104 of the
subroutine illustrated in the flow chart, FIG. 6, is applied to the
reverse motor step 105. When the motor has been reversed, the
condition of the motor is again checked to see if it is stalled. If
so, there is an output signal to a subsequent stop mode step 108.
Ordinarily, however, the motor will not be stalled and the next
stage 107 of the flow chart receives an enabling signal to check
and see whether the comb is in its "home" position. If not, a
feedback signal is supplied to stage 106. When comb 43 reaches its
"home" position, at storage end 29 of litter box 20, there is an
output signal from stage 107 to a stop motor stage 108 which in
turn supplies an output signal to a return stage 109. This
Completes the subroutine of FIG. 6.
FIG. 7 illustrates a further subroutine that is also programmed
into micro processor control 96 (FIG. 5). It starts with a power-on
stage 111 that may be initiated by an appropriate switch (not
shown) or may start simply with insertion of appropriate batteries
into battery case 55 (FIGS. 1-3). The next stage 112 in this
subroutine is initialization of the micro controller operation. In
the next subroutine stage 113, the micro controller checks to
determine whether the mode select switch 91 of FIG. 5 is set for
manual mode. If it is, a comb litter procedure is initiated in step
114 and there is a feedback output back to subroutine stage 113. So
long as the manual mode is maintained, self-cleaning of the litter
box is continued on a cyclical basis. This may be desirable when
the person using litter box 20 wants to make sure that all clumps
have been removed from the litter in the box so that the liter can
be replaced.
If the program is not set for manual mode, a NO output from stage
113 goes to he next stage 115 in the subroutine of FIG. 7 to check
the condition of the batteries. If a low battery voltage condition
is ascertained, there is an output to the next stage 116 which in
turn may actuate a sound alarm stage 117 to produce a programmed
output from buzzer 97 (FIG. 5) that alerts the use of litter box 20
that a change of batteries is required. Outputs from stages 116 and
117 may be fed back to stage 113 in this subroutine in appropriate
circumstances. Ordinarily, however, when the voltages of the
batteries are adequate, there is a NO output from stage 115 and it
iS supplied to a stage 118 that determines whether the Septic or
waste receptacle 68 (FIGS. 1-3) is full. Ordinarily, the receptacle
will not be full but if it is, there is again a feedback signal
supplied back to stage 113.
In normal circumstances, with adequate room in the septic
receptacle, there is a NO output from stage 118 that is applied to
a subsequent stage 119 in the subroutine of FIG. 7. The normal YES
output from stage 119 goes to a subsequent stage 121 for the micro
control to determine whether the comb of the self-cleaning litter
box is at its home position as shown in FIG. 1. The YES output of
stage 121 is applied to a subsequent subroutine stage 122 that
determines whether a cat is present in the litter box. If a cat is
present, there iS a YES output from stage 122 to a delay stage 123
in the program for this subroutine. When the cat leaves the litter
box, a YES output from stage 123, after the appropriate delay of
several minutes, is supplied to a comb litter stage 124 that is the
last stage in this subroutine. The comb litter stage 124 is the
source of the comb litter command 101 of FIG. 6. As shown in the
flow chart of FIG. 7, NO outputs from either of the stages 121 and
122 result in a feedback signal to stage 113. The output from comb
litter stage 124 at the end of the subroutine is also a feedback
signal to stage 113.
The automated self,cleaning litter box 20 does not frighten or
disturb a cat; the self-cleaning movement of comb 43 does not occur
until there is a reasonable certainty that a cat using the litter
box has been gone for two to seven minutes, depending on the delay
set into the control after exit of a cat is determined before motor
55 is energized. Other sensors can be used instead of photo
detectors 82 and 94. For example, infra,red sensors receiving
radiation from an appropriate I-R source, or a strain gauge on pan
bottom 26, will serve the same purpose as the photo detectors of
FIGS. 1-4.
The gear drive connecting motor 55 to shaft 41 is not subject to
fouling by the litter, which often includes powdery material that
is likely to interfere with operation of other drive mechanisms
such as a worm drive. Motor 55 should be sealed against dust and
dirt, since it must operate in a rather adverse environment. Litter
box 20 is simple and economical in construction, but should afford
an extended operating life with little or no attention apart from
periodic replacement of the litter and replacement of the batteries
56.
The detail sectional view of FIG. 8, which is similar to FIG. 4,
illustrates a sensor for determining whether there is an adequate
supply of litter in the litter box. FIG. 8 again affords a
sectional view of housing 21, including side walls 22 and 23 and
bottom 26, Also shown are cat detector components comprising light
source 86 and photo detector 82, both located well above an
internal ridge 138 in the housing that indicates the desired upper
level for the litter. Ridge 138 may be continuous around all sides
of the litter box, or it may be interrupted if desired. Comb 43 and
its tines 44 also appear in FIG. 8.
The variation shown in FIG. 8 also includes a sensor for
determining whether there is an adequate supply of litter in the
litter box. The litter level sensor comprises a radiation source
142 mounted on the inside of housing wall 22 in alignment with a
detector 143 that is mounted on wall 23. Devices 142 and 143i are
selected to work together; if the radiation from source 142 is in
the visual range, detector 143 is a photo sensor. If an infra red
source is used, an infra red detector becomes necessary. Devices
142 and 143 are located immediately below the level indicator 138.
If radiation from source 142 reaches detector 143, the level of
litter in housing 21 is insufficient and should be supplemented.
The litter level sensor 142, 143 is used to actuate an appropriate
alarm 97, FIG. 5.
In the detail section view of FIG. 9, the waste receptacle 68 and
its lid 69 are shown in closed condition. There is a mass 271 of
Waste in receptacle 68, but the receptacle is not yet full.
Receptacle 68 is positioned in the litter box by engagement with
bosses 222A and 223A on the bottoms of two litter box wall
extensions 222 and 223 which may be affixed to litter box housing
walls 22 and 23, respectively; see FIGS. 1-3. The position of
receptacle 68 may also be determined by engagement with two lateral
extensions 224 of walls 222 and 223.
In the arrangement shown in FIG. 9, the walls of waste receptacle
68 and cover 69 adjacent extension/positioning wall 222 are
provided with aligned openings 226 and 228, respectively. At the
other side of the waste receptacle, adjacent positioning wall 223,
the waste receptacle and its cover have similar aligned openings
227 and 229, respectively. Moreover, holes 226 and 228 are aligned
with apertures 227 and 229 so that radiation from a source 242 on
wall 222 impinges upon a detector 243 on wall 223 as long as the
level of waste 271 in receptacle 68 does not block the
radiation.
When receptacle 68 is full, the waste in the receptacle cuts off
the radiation, so that there is no longer an output from detector
243. Consequently, the sensor system 242, 243 of FIG. 9 is able to
actuate an alarm 97 (FIG. 5) to signal to the user that waste
receptacle 68 is full and should be replace.
* * * * *