Self-cleaning litter box
A self-cleaning litter box for cats employs a comb drive to drive a comb through litter to remove waste from the litter. A sensor for detecting the presence of an obstruction is coupled to the comb drive and stops the comb drive upon detecting an obstruction. A manual mode selector switch and an actuating switch are provided to manually activate the cleaning of the litter box at a time deemed appropriate by the cat owner. A foot pedal unit may be provided for semi-automatic use. A removable tray for cat litter may be provided. The tray may be disposable. A pivotable ramp facilitates ingress to, and egress from, the litter box. The ramp may be carpeted. A tray receives the litter box and a hood encloses the litter box to provide privacy.
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The present invention is directed to litter boxes and particularly to self-cleaning litter boxes for cats. This application is a divisional application of U.S. application Ser. No. 09/118,081 filed Jul. 17, 1998, now U.S. Pat. No. 6,082,302 dated Jul. 4, 2000.
BACKGROUNDCats 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 cat litter boxes have been proposed, as in the construction described in U.S. Pat. No. 5,249,549 (Rockaitis), 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 or other materials that absorb moisture from the waste of the cat. The material may also suppress odor from cat waste. 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 a 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 waste 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 may find the task of emptying the cat litter to be unpleasant. Thus, a number of devices have been proposed for cleaning cat litter boxes. Such devices are disclosed in U.S. Pat. No. 4,096,827 (Cotter), U.S. Pat. No. 4,117,804 (Moore et al.), U.S. Pat. No. 4,190,525 (Menzel), U.S. Pat. No. 4,325,325 (Larter), U.S. Pat. No. 4,325,822 (Miller), U.S. Pat. No. 5,048,465 (Carlisi), U.S. Pat. No. 5,226,388 (McDaniel), and U.S. Pat. No. 5,477,812 (Waters).
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. At predetermined intervals, the comb is moved through the litter, 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. Unfortunately, because cats are not consistent in their elimination habits, such periodic clearing may be too frequent, or not frequent enough.
The Waters patent describes a system for moving a comb or rake through the litter responsive to entry and exit of the cat from the litter box. In addition, Waters provides an improved disposal receptacle and alarms to report an insufficient litter supply and a full disposal receptacle. The entire disclosure of the Waters '812 patent is incorporated herein by reference.
Despite the advances made by these prior art patents, there remains several deficiencies in self-cleaning litter boxes. First, if the cat is present in the litter box while the rake or comb is moving, the cat may be startled to move suddenly and spill the contents of the litter box or, the cat could be caught by the mechanism. Second, devices that require the passage of time or the activity of a cat to initiate the rake drive mechanism do not allow for use of the rake at other times. Third, easy access is needed to aid cats in entering and exiting the litter box. The open boxes allow litter to be spilled out and do not provide cover for cats that may desire privacy.
SUMMARYThe present invention alleviates to a great extent the deficiencies of the prior art by providing a litter box having a housing defining an upwardly open litter chamber for receiving cat litter, a comb disposed in the litter chamber, a carriage supporting the comb, and a comb drive for driving the comb between a storage position and a discharge position. The comb drive includes a reversible drive motor mounted on the carriage. A reverse sensor is coupled to the carriage. The reverse sensor is coupled to a first surface of the carriage and the sensor provides a shut-off signal to the comb drive when the sensor detects that the carriage has contacted a cat, or other obstruction, while moving between the storage position and the discharge position. According to one aspect of the invention, the reverse sensor includes a switch electronically coupled. to the drive motor for providing the shut-off signal to the comb drive in the closed position. In one embodiment of the invention, the reverse sensor is a leaf switch.
In another aspect of the invention, the litter box has a mode selector switch. The switch may have a manual operation selecting position and an automatic operation selecting position. In addition, a manual operation switch may be electrically connected to the mode selector switch. According to another aspect of the invention, the comb drive drives the comb between a storage position and a discharge position in response to actuation of the manual operation switch when the mode selector switch is in the manual operation selecting position.
In yet another embodiment of the invention, a rectangular tray has side walls and a bottom wall that cooperate to define a housing-receiving region. Hood supports are coupled to the rectangular tray. A hood is coupled to the supports. The hood includes an opening for a cat to enter or exit the litter box. According to another aspect of the invention, a housing access ramp is pivotally connected to the housing, preferably at the opening.
In still another embodiment of the invention, the litter chamber includes a removable litter tray for receiving the cat litter.
The present invention may also be provided with means for ensuring that the comb stops when it strikes a cat while moving between the storage and discharge positions. By stopping the comb, the situation in which a cat is pinned between the comb and a wall is prevented.
The invention provides a manual cleaning mode that allows the cat owner to initiate the waste removal upon the activation of a switch. This mechanism would allow the cat owner to clean the waste out of the litter box at a time deemed appropriate by the cat owner.
The invention also provides an enclosure for a self-cleaning litter box to provide privacy for the cat. The enclosure could also be used to prevent litter from being spilled out of the box.
Other features and advantages of the present invention will be readily apparent from the following description and drawings which illustrate preferred embodiments of the invention.
A comb shaft 41 extends across the litter box 20 between two side tracks 32, 33. There are four hangers 42 journalled on and depending from the shaft 41. Three of the hangers 42 appear in
An elongated near side track or path member 32 extends along the top of the near side wall 22 of housing 21. Track member 32 includes a multiplicity of equally spaced apertures 31. Apertures 31 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 20. 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 39. The pattern of apertures extends along an inclined portion 35 of the track member 33 at the discharge end 28 of litter box 20. It also extends along a more steeply inclined portion 37 of the track 33 located at the comb storage end 29 of the litter box 20.
A first main guide wheel 52 is affixed to the near end of shaft 41. Guide wheel 52 includes a plurality of radially projecting guide pins or teeth 51 engageable in the apertures 31 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 54 on guide wheel 53 are engageable in the apertures 39 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
In addition to the main guide wheels 52, 53 referred to above, the drive and guidance system of litter box 20 includes two auxiliary guide wheels 64, 65, located on the near and far sides of the litter box 20, respectively, as seen in
The improved self-cleaning cat litter box 20,
A waste receptacle 68 is positioned immediately adjacent to the discharge end 28 of the litter box 20. In
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 68 is ready to be discarded, it can simply be removed and a new receptacle 68 put in place after emptying clean litter from the new waste receptacle 68 into the chamber afforded by housing 21.
A sensor may be used to determine whether or not the receptacle is full. In the embodiment of
Another sensor may be utilized to sense the exit of a cat from the litter chamber afforded by housing 21. In the embodiment of
As shown in
Other features are also illustrated in
As shown in
As illustrated in
When the litter tray 300 is disposed in the litter box 20, the locking tab 302 engages the notches 328 to retain the tray 300 in the litter box 20. To remove the tray 300, a user inserts a finger into the semicircular opening 327 and depresses the resilient locking tab 302, causing the tab 302 to disengage from the notches 328. Although a locking projection 320 and a locking tab 302 have been illustrated, it will be appreciated that other latching mechanisms can be used. The locking tab 302 is preferred, however, because it is easy to operate and is readily formed integrally with the removable tray during the molding process.
In addition to the locking tab 302, the litter box 20 includes a pair of tray locks 330, illustrated in
As illustrated in
To remove the litter tray 300, as illustrated in
In the preferred embodiment of the present invention, as shown schematically in
Referring to
When the carriage 45 contacts a cat, or other obstruction, a force is applied to the reverse sensing bar 402, and the force is transmitted to the flexible leaf switch arm 426 by the actuating bar 408. The actuating bar 408 pushes the leaf switch arm 422 to bend the arm 422 around the leaf switch arm separator 424, causing the leaf switch contact 425 to touch contact 423. The leaf switch 410 is closed, and an electrical connection is maintained, while the contacts 423, 425 are in contact with each other. When the leaf switch 410 is closed, a signal is generated to stop and reverse the motor 55 (described below).
The leaf switch 410 is resiliently biased toward its open position (that is, the contacts 423, 425 are biased away from each other). The leaf switch 410 will be closed (as described above) when the sensing bar 402 contacts the end wall 25 and the contact 425 of the flexible leaf switch arm 426 is forced into contact with the contact 423 of the rigid leaf switch arm 422.
Referring now to
The mode select switch 91 (
The motor stall sensor 92 determines whether the motor 55 is stalled. If the motor 55 is started by the control 96, but becomes stalled, the motor stall sensor 92 will supply a motor stall input to the control 96.
The battery voltage sensor 93 determines whether there is a low battery voltage condition. If there is a low battery voltage condition, the battery voltage sensor 93 supplies a low battery voltage condition input to the control 96. The control 96 sends a signal to sound a buzzer 97 when the low voltage input is received.
The home position sensor 94 for the comb 43 determines whether the comb 43 has reached the “home” position. If the comb 43 has reached the “home” position, the home position sensor 94 supplies a “home” position input to the control 96. In response to the home position input, the control 96 stops the motor 55.
A manual operation foot switch 370 (
Limit switches 95, 99 may be provided at the storage end 28 and at the discharge end 29 of the litter box 20. One or more buzzers or other alarm devices 97 are included in the circuit so that the cat owner can be signaled when the litter box 20 is functional or when other conditions occur, such as an insufficient litter supply in the box 20 or a fill waste receptacle 68 or low battery voltage.
If desired, the apparatus 200 may be provided with a shut-off timer system (not illustrated). The shut-off timer system may be used to disable operation of the apparatus 200 for a predetermined period of time, for example, six hours. Thus, for example, the apparatus 200 may be disabled during the middle of the night, so that the apparatus 200 does not disturb resting persons or other pets. A push button over-ride system (not illustrated) may be provided to manually initiate a raking operation when the apparatus 200 is otherwise disabled by the shut-off timer system.
The motor stall sensor 92, battery voltage sensor 93, buzzer 97, and leaf switch 410 of reverse sensor 400 may all be packaged in the same housing with the motor 55. Such packaging would be particularly advantageous by eliminating the need for long wiring runs.
The mode selector switch 91, home position sensor 94, limit switches 95,99 and manual operation switch 370 can be incorporated in the litter box 20 in appropriate positions as desired. Home position sensor 94 may be coupled to or adjacent to the “home” position. For example, if the “home” position is determined to be the storage end 29, then the sensor 94 should be located adjacent to the storage end wall 25. Limit switch 95 can be positioned to be actuated by any part of the comb 43 or the carriage 45. The limit switch 95 is disposed at the storage end 28 of litter box 20 and is activated when the comb 43 or carriage 45 reaches the storage end 28 of the litter box 20. The limit switch 99 is disposed at the discharge end 29 of litter box 20 and is activated when the comb 43 or carriage 45 reaches the discharge end 29 of the litter box 20. Manual operation switch 370 can be positioned adjacent the mode select switch 91, the carriage 45 or any other desired location on the litter box 20.
In operation, the comb 43 may initially be located at the comb storage end 29. In this condition, the comb shaft 41 is elevated, the guide wheels 52, 53 having ridden up the extensions 36, 37 of tracks 32, 33. The switch 58 and the lever 59 have engaged the pin 61; the motor 55 is shut off, but is set for forward movement. Removable tray 300 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 (
At this juncture, it may be assumed that a cat (not illustrated) enters the 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. 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, especially 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 of the removable tray 300 (
While the cat is present in the litter box 20, 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 the litter box 20. Subsequently, when the cat leaves the litter box 20, the light beam or beams again impinge upon the photo detectors. Accordingly, an output signal from one or both cat sensors is supplied to control 96 (
Ultimately, the cat leaves the litter box 20 for an interval long enough to exceed the preset time delay that is set into 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 the 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 20.
In a preferred embodiment, the operation of the self-cleaning litter box 20 can be also be performed manually. Instead of waiting for the predetermined delay period, as previously described, cleaning of the litter box 20 may be initiated by the cat owner. Manual operation can be achieved by placing the mode select switch 91 (
After the cat has left litter box 20 for a time exceeding the preset delay interval in control 96 (automatic operation) or after the manual operation switch 370 has been activated (in manual mode), motor 55 is energized from battery 56, or a conventional power supply (not shown), through control 96. As a consequence, gear 57 and shaft 41 are rotated in the direction of the arrow B in
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, from the storage end 29 to the discharge end 28, as indicated in
Ultimately, the comb 43 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 45 moves up the ramps or track extensions 34 and 35 to the position shown in
When comb 43 reaches the position of
When comb 43 has finished its movement back to a point closely adjacent to the storage end wall 25, its two main guide wheels 52 and 53 encounter the steeply inclined upward extensions 36, 37 of tracks 32, 33. Motor 55 remains energized and pulls comb 43 and its shaft 41 up to the position shown in
In a preferred embodiment, a reverse sensor 400 (
When the motor 55 has been reversed, the condition of the motor 55 is again checked to see if it is stalled. If so, there is an output signal to stop the motor 55 (step 108). Ordinarily, however, the motor 55 will not be stalled and an enabling signal is received (stage 107) to check and see whether the comb 43 is in its “home” position. When comb 43 reaches its “home” position, at storage end of litter box 20) there is an output signal sent to stop the motor 55 (stage 108) which directs the subroutine to return to the beginning of the subroutine (stage 109). If the comb 43 has not reached the “home” position, the subroutine proceeds to stage 107A to determine if the reverse sensor 400 has been activated. If the reverse sensor 400 has not been activated, the subroutine returns to stage 106 and checks for a stalled motor 55. If the reverse sensor 400 has been activated, there is an output signal (stage 107A) to a stop motor (stage 108). The subroutine then returns to the beginning (stage 109). This completes the subroutine of
If the manual operation mode is selected, the control 96 checks to determine if a manual operation switch 370 (
If the program is not set for manual mode, the subroutine checks for a low battery condition (stage 115). If a low battery voltage condition is ascertained, the subroutine checks to see if the alarm mode is set (stage 116) and, if the alarm mode is set, the subroutine actuates an alarm (stage 117) to produce a programmed output from buzzer 97 (
In normal circumstances, with adequate room in the receptacle 68, the subroutine checks to see if any septic is present (stage 119). If septic is present, the subroutine checks to determine if the comb 43 is in the “home” position (stage 121). If the comb 43 is in the home position, the subroutine checks for the presence of a cat in the litter box (stage 122). If the comb is not in the home position, or if the cat is not present in the litter box, the subroutine returns to the mode check (stage 113) and begins again. If the cat is present in the litter box, the subroutine waits for the delay time to expire (stage 123) and then executes a comb litter command (stage 124) and returns to the mode check (stage 113) and begins again.
Thus, the automated self-cleaning litter box 20 may be arranged so as not to frighten or disturb a cat; the self-cleaning movement of the comb 43 may not occur until there is a reasonable certainty that a cat using the litter box 20 has been gone for two to seven minutes, depending on the delay set into the control 96, before the 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 infra-red source, or a strain gauge on pan bottom 26, may serve the same purpose as the photo detectors of
The gear drive 57 that connects 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 an 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.
In a preferred embodiment of the present invention, as shown in
In order for the ramp 350 to be connected to the housing 21, the two side walls 22, 23 may include first and second pivot holes 360, 362 at the discharge end 28 of the litter box 20. The ramp 350 is attached to the housing 21 by placing the first pivot pin 354 and the second pivot pin 356 into pivot holes formed in the side walls 22, 23 of the litter box 20. The carpeting 352 is facing up as depicted in
Another feature of a preferred embodiment of the present invention, as shown in
Another aspect of the tray 500 is that it may be used to cooperate with a dome or hood 548 to define an enclosure 550 for the self-cleaning litter box 20. The dome 548 may be used to provide privacy for the cat. The enclosure 550 includes a plurality of hood supports 530. The hood supports 530, may be metal or plastic strips. Each hood support 530 has a first end portion 532 and a second end portion 534. To accommodate the hood supports 530, the first and second side walls 504, 508 have a plurality side of wall openings 510. The openings 510 are adapted to receive the hood support end portions 532, 534.
The hood supports 530 are placed into the side wall openings 510 such that the end portions 532, 534 are retained therein by the resiliency of the hood supports 530 acting against the side walls 504, 508. The hood 548 is placed over the hood supports 530 forming the enclosure 550. The hood 548 has an opening 552 and may be made of cloth or any suitable material and may be connected to the hood supports 530 in any manner. For example, the hood supports 530 may be sewn into the hood 548. Alternatively, the hood 548 may have ties that connect the hood 548 to the hood supports 530. Alternatively, the hood 548 can drape over the supports 530 and attach to the sidewalls 504, 508.
While the invention has been described in detail in connection with preferred embodiments known at the time, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention.
Claims
1. A cat litter apparatus, comprising:
- a litter chamber;
- an enclosure located over said litter chamber, said litter chamber being removable from said enclosure;
- a removable litter tray disposed in sliding engagement with a bottom of the litter chamber to receive the litter; and
- a tray lock latching mechanism for selectively retaining the tray in the litter chamber, said tray lock latching mechanism comprising a resilient locking tab on a selected one of said tray and said litter chamber and a locking projection on the other of said tray and said litter chamber, said tab being removably retained in by said projection as a result of said tray being completely slid into the litter chamber.
2. The apparatus of claim 1, wherein the further comprising a tray lock that is selectively moved between a locking position and an unlocking position, a portion of said tray lock interfering with an end of the removable tray to also retain the tray in the housing said litter chamber when the lock is in the locking position.
3. The apparatus of claim 1, further comprising:
- a comb disposed in said litter chamber;
- a comb drive coupled to said comb and including a drive motor; and
- a sensor coupled to said drive motor and positioned to detect contact with an obstruction while said comb moves between a storage position and a discharge position.
4. The apparatus of claim 3, wherein said sensor provides a shut-off signal to said comb drive in response to detection of the obstruction.
5. The apparatus of claim 4, wherein said sensor includes a switch electrically coupled to said drive motor, said switch being movable between an open position and a closed position, said switch providing the shut-off signal to said comb drive when in the closed position.
6. The apparatus of claim 5, wherein said sensor is a leaf switch.
7. A litter box, comprising:
- a housing defining a litter chamber;
- a removable tray for receiving cat litter, said tray being located in the litter chamber and being in slidable engagement with a bottom of the litter chamber;
- a comb movably disposed in the removable tray for raking the cat litter supported in the tray; and
- a lock latching mechanism for retaining the removable tray in the housing, the lock latching mechanism including a locking projection coupled to the housing and a resilient locking tab coupled to the removable tray, the locking tab selectively engaging the locking projection as a result of said tray being completely slid into the litter chamber.
8. A cat litter apparatus, comprising:
- a litter chamber;
- a removable tray disposed in sliding engagement with a bottom of the litter chamber to receive the litter; and
- a latching mechanism adapted to selectively retain the tray in the litter chamber, the latching mechanism comprising a resilient locking tab on the tray and a locking projection on the litter chamber, the tab being removably retained by the projection as a result of said tray being completely slid into the litter chamber.
9. The cat litter apparatus, as set forth in claim 8, comprising a lid coupled to the litter chamber.
10. The cat litter apparatus, as set forth in claim 8, wherein the tray is formed of a plastic material.
11. The cat litter apparatus, as set forth in claim 8, wherein the tray is disposable.
12. A litter box, comprising:
- a litter chamber;
- a removable tray adapted to receive litter, the tray being located in the litter chamber;
- a comb movably disposed in the litter chamber between a storage position and a discharge position, the comb being drivable by a motor to rake the litter supported in the tray;
- a sensor coupled to the motor and positioned to detect contact with an obstruction when said comb is between the storage position and the discharge position; and
- a latching mechanism for retaining the removable tray in the housing, the latching mechanism including a locking projection coupled to the housing and a resilient locking tab coupled to the removable tray, the locking tab selectively engaging the locking projection.
13. The litter box, as set forth in claim 12, comprising a lid coupled to the litter chamber.
14. The litter box, as set forth in claim 12, wherein the tray is formed of a plastic material.
15. The litter box, as set forth in claim 12, wherein the tray is disposable.
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Type: Grant
Filed: Apr 30, 2004
Date of Patent: Apr 16, 2019
Assignee: Spectrum Brands, Inc. (Middleton, WI)
Inventors: Pauline Thaler (Weston, FL), Philip Y. H. Cheung (Hong Kong)
Primary Examiner: Russell D Stormer
Application Number: 10/837,273
International Classification: A01K 1/01 (20060101); A01K 29/00 (20060101);