Abstract:
An improved automated litter box comprises a motorized comb or rake drive mechanism for removing clumps, a means for cycling the drive mechanism, and a cat proximity sensor for sensing the relative position of a cat about or within said litter chamber. The cat proximity sensor is capable of identifying the location of a cat outside the litter box or litter box or litter chamber. The cat proximity sensor comprises a passive or inductive transmitter for identification for modulating and demodulating a radio frequency (RF) signal; and an antenna for receiving and transmitting a radio frequency (RF) signal.

Description:
RELATED APPLICATIONS 
     The present application is a continuation of U.S. Application No. 61/012,839, filed Dec. 11, 2007 and claims benefit of that provisional&#39;s priority date. All applications are incorporated herein by reference thereto as though recited in full. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is directed generally to automated self-scooping litter boxes, and, more particularly, to a novel and improved method of initiating a scooping or cleaning cycle therein. 
     2. Description of the Related Art 
     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 a re-useable plastic or like material. Such a material does not allow a cat&#39;s urine to leak through the box, while at the same time provides an efficient, cleanable and reuseable waste container. 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 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. 
     A number of prior art devices have been proposed for automating the cleaning of cat litter boxes; devices of this kind are disclosed in U.S. Pat. No. 4,096,827, U.S. Pat. No. 4,117,804, U.S. Pat. No. 4,190,525, U.S. Pat. No. 4,325,325, U.S. Pat. No. 4,325,822, U.S. Pat. No. 5,226,388 and U.S. Pat. No. 5,048,465. 
     Typical of these self-cleaning cat litter box designs are to utilize a rake or comb that is moved through the litter, periodically. The rake encounters and discharges any clumps collected by the comb into a disposal receptacle. 
     Of considerable relevance is U.S. Pat. No. RE36,847, issued in the name of Waters, for an improved automated self-cleaning litter box for cats, of the kind having a comb that is driven forward through the litter to a discharge end of the chamber where the clumped litter is then discharged from the litter box. The improvement of the &#39;847 reference is focused primarily around a sensor for sensing the presence of a cat in the litter chamber, in which 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. 
     As typified by the &#39;847 reference, sensing the presence of the pet can be an important consideration, given a particular design for such an automated litter box. If the comb driving mechanism pushes the litter out of the box to a discharge end (as in the &#39;847 reference), when the comb drive mechanism returns is can cause a potential impingement hazard to an animal that may be in the way. Similarly, if the scooping mechanism retrieves and stores the waste in a laterally articulated fashion (as in the U.S. patent application Ser. No. 11/708,368), a similar impingement hazard can occur. In order to prevent such a hazard, various strategies of sensor in combination with timers have been employed. However, all such strategies so far developed cannot accurately determine when to initiate an automated cleaning or scooping cycle, i.e. after the litter box has be used, but only after the animal has exited. 
     A search of the prior art did not disclose any patents that read directly on the claims of the instant invention; however, the following references were considered related. 
     U.S. Pat. No. 7,230,539, issued in the name of Klein, teaches a “Pet Identification Tag with Internal Cavity for Transponder Capsule”, wherein a pet tag comprises an internal cavity that removably contains an FRID capsule transponder wrapped in a thick paper having a thin layer of metal that shuts out electromagnetic fields, so that consumers can select tracking options. 
     U.S. Pat. No. 6,283,065, issued in the name of Shorrock, et al., teaches a collar stud attachable to a pet collar to function as an identification device with two modes: (1) a visually discernible identification code; or, (2) an RFID transponder device programmed with a unique code so that the stud serves as an electronic identification tag for the host animal. The code is made part of the data records at a health care database to aid in locating a lost pet. The electronics may further promote feed control, wherein the dish opens to allow the pet to feed with it is in proximity. 
     Further, radio-frequency identification (RFID) tags or transponder device are commonly available and utilized to store and remotely retrieving data. An RFID tag is an object that can be applied to or incorporated into a product, animal, or person for the purpose of identification using radiowaves. Some tags can be read from several meters away and beyond the line of sight of the reader. Most RFID tags contain at least two parts. One is an integrated circuit for storing and processing information, modulating and demodulating a (RF) signal and can also be used for other specialized functions. The second is an antenna for receiving and transmitting the signal. A technology called chipless RFID allows for discrete identification of tags without an integrated circuit, thereby allowing tags to be printed directly onto assets at lower cost than traditional tags. RFID tags come in three general varieties: passive, active, or semi-passive (also known as battery-assisted). Passive tags require no internal power source, thus being pure passive devices (they are only active when a reader is nearby to power them), whereas semi-passive and active tags require a power source, usually a small battery. 
     While the present invention anticipates the use of a self scooping or otherwise automated litter box having a sensor initiated automation cycle incorporated into this invention in combination, other elements and improvements are different enough as to make the combination and improvement distinguished over the these references and the inventors&#39; own prior art. 
     Consequently, a need has been felt for providing an apparatus and method of accurately and safely initiating the automation cycle of such devices. 
     SUMMARY OF THE INVENTION 
     It is a principal object of the present invention, therefore, to provide a new and improved drive sensor mechanism for initiating the movement of a rake or comb employed to remove litter from a cat litter box in an automated litter box device. 
     It is another object of the present invention to initiate such a cleaning cycle in a manner that is accurately responsive to the exit of a cat from the litter box. 
     It is a further object of the invention is to accurately sense the presence of a cat relative to the location of an automated litter box. 
     Finally, it is an object of the present invention to accurately sense when an animal has utilized a litter box, thereby providing reliable input for initiation of a cleaning or automated scooping cycle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The advantages and features of the present invention will become better understood with reference to the following more detailed description and claims taken in conjunction with the accompanying drawings, in which like elements are identified with like symbols, and in which: 
         FIG. 1  is an elevational view of the automated cat litter box according to the preferred embodiment of the present invention; 
         FIG. 2  is an elevational view of a tray according to the invention shown in  FIG. 1 ; 
         FIG. 3 . is an alternate embodiment to the automated cat litter box, wherein a hand crank is used to replace the motorized driving mechanism; 
         FIG. 4  is a litter box lid, wherein the construction is specific to and accommodates the design features of the automated cat litter box disclosed therein; 
         FIG. 5  is a perspective view of a commercial embodiment of the present invention; 
         FIG. 6  is a pictorial representation of a novel and improved method of initiating a scooping or cleaning cycle according to the preferred embodiment of the present invention; and 
         FIG. 7  is an electrical schematic therefor. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In order to describe the complete relationship of the invention, the present description is described as an improvement to an automated, self scooping litter box design as shown, described and claimed in U.S. Ser. No. 12/175,612. However, such a description is used only to give a typical relationship to the terms and functions of the present invention. It should be noted that in describing the present invention, it is anticipated that such an improvement can be implemented in conjunction with number of such automated cleaning or scooping litter box designs, and such should be broadly read into the definitions that are used throughout this application. 
     The best mode for carrying out the invention is presented in terms of its preferred embodiment, herein depicted within the Figures. 
     1. Detailed Description of the Figures 
     The automated cat litter box  10  according to the preferred embodiment of the present invention is shown in  FIGS. 1-3 . To achieve the objectives of the present invention, the preferred embodiment comprises a deep rectangular litter pan  12   a  having a ramp  14  along its width at one end and a self-cleaning carriage  12   b  resting at the opposite end. The self-cleaning carriage  12   b  preferably comprises a waste drawer  16  having a rotating grate  18  vertically attached thereto. The length of the waste drawer  16  travels along the width of the litter pan  12 ; its depth approximates half the depth of the litter pan  12 . A lid  20  is hingedly attached to the waste drawer  16  along its length. 
       FIG. 2  shows a tray  26  that is sized to fall into and fit into the waste drawer  16 . A disposable and non-reusable plastic covering  30 , or lining, is placed over the tray  26  so that waste can be speedily and easily removed. A handle  28  is positioned at the tray&#39;s  26  end so that the tray can be lifted out of the drawer  16  and the waste discarded. The handle  28  extends outwards through a window formed by a rectangular indentation  32  on the top edge of the drawer  16  and a curved indentation  34  on the edge of the lid  20  when the lid  20  is in a closed position. 
     The self-cleaning carriage  12   b  rests on the lip  22  of the pan  12  by means of an engagement rail  24 . When the litter is self-cleaning, the self-cleaning carriage  12   b  travels along the lip  22  and also travels a guiding rim  36  extending outwards from the interior sidewall of the pan  12   a . While the engagement rail  24  is carrying the entire self-cleaning carriage  12   b  along the length of the pan  12   a , litter passes through the tines  38  of the rotating grate  18  while clumps of waste are pushed forward. The tines  38  can be straight or curved so as to better shovel the waste in the cleaning process. Towards the end of the guiding rim  36 , the grate  18  rotates from its vertical position and climbs the curved shallow end of the pan  12   a  to a horizontal position. The grate  18  then flips backwards by means of a pivot rod  40  to shovel all of the clumped waste that the tines  38  sifted out of the litter into the tray  26  behind it. The grate  18  mechanically returns to the vertical position and the cleaning carriage  12   b  returns backwards along the same guiding rim  36  to its resting position. 
     The self-cleaning carriage  12   b  travels the length of the pan  12   a  by means of a motorized driving mechanism (not shown) housed in a cabin  42  attached to and adjacent to the drawer  16 . It is envisioned that the cabin  42  is positioned outside of the litter box  10  so as to not consume any additional litter containing space in the litter pan  12   a . A push lock release  44  positioned on the top of the cabin  42  provides access to the motor and the mechanical elements used to drive the cleaning carriage  12   b.    
     In an alternate embodiment to the present invention, shown in  FIG. 3 , a hand crank can be used to drive the self-cleaning carriage  12   b . In this embodiment, the driving mechanism is still housed in the cabin  42 , but it is not motorized. 
     Another functional element comprised in the preferred embodiment includes horizontal ribs  48  extending across the ramp both to assist the cat in ingress and egress and to assist in catching any litter or clumps caught on the cat&#39;s paws before it is tracked throughout the home. Circular grooves  50  positioned on the lip  22  of the pan  12   a  at its four corners also provide a means for a litter box lid to be placed over the pan  12   a.    
     A litter box lid  100  is shown in  FIG. 4  according to the preferred embodiment of the present invention. The litter box lid  100  is designed to accommodate the features of the automated cat litter box  10  disclosed above. The lid  100  comprises a removable and washable fabric cover  110  held in position by a wire or sturdy frame  120 . The frame  120  travels the length of the pan  12   a  having four pins  130  extending downwards at its ends to snap into the circular grooves  50  positioned on the corners of the automated litter box  10 . The pins  130  also elevate the lid  100  so that the cleaning carriage  12   b  can travel below it and along the pan&#39;s lip  22  during an automated cleaning. The cover  110  covers the pan  12   a  from in front of the self-cleaning carriage  12   b  to its opposite end. A ventilation hole  140  or filter positioned on the top of the lid provides fresh air to the internal space created there between. 
     As shown in conjunction with  FIG. 6  and  FIG. 7 , the improved automated self-scooping litter box  20  further comprises a radio frequency identification (RFID) sensor located on or worn by the animal to accurately and repeatably sense the presence of a cat in relation to the housing  21  in which an RFID receiver is located. Herein, RFID and any form of inductive transmitter are used interchangeably. A block diagram for the operating circuit of the improved automated self-cleaning litter box  20  is presented in  FIG. 7 . 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. 
     2. Operation of the Preferred Embodiment 
     In operation, it may be assumed that a cat (not illustrated) wearing a radio frequency passive transmitter as a lightweight identification tag enters litter box  20  for the purpose of elimination of either liquid or solid waste. The receiver accurately knows when the cat approaches the limited transponder range, and can track the animal continuously within this range. In fact, the animal can be tracked such that any automation cycle in not initiated until after the animal has entered the litter box, or entered the litter box for a sufficient time. Further, rather than a standard or random time delay before actuation of the rake or comb drive, the current design can delay such actuation until after the animal exits the litter box and moves to a safe distance therefrom. In such a circumstance, there is no need to utilize an estimated time after the animal breaks a photo detector beam to assume that the animal is done utilizing the device. Similarly, the cleaning cycle can be actuated immediately upon the cat moving a sufficiently safe distance away from the device. 
     Such a method and device eliminate any safety concerns with the rake or comb drive of the device operating while an animal is in (or near). Further, such an apparatus and method can allow operation of the device immediately, without delay, as soon as the animal is done utilizing the litter box. 
     The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of enabling an illustration and description as required by (Cite the enablement section for PROVISIONALS). They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined broadly by the Drawings and Specification and Claims appended hereto and their equivalents. Therefore, the scope of the invention is in no way to be limited only by the following exemplary claims.