Abstract:
A cat scratcher system for providing at least one surface suitable for cat scratching. This system includes a shell being capable of accepting at least one cat scratching insert, the shell having sides, an opening for inserting and removing the first cat scratching insert and a top and bottom. At least one of the shell surfaces, such as the top, is further characterized as having an open region for displaying a first cat scratching surface of the insert to the exterior of the shell. The system contemplates the use of replaceable inserts used as current cat scratching surfaces become degraded upon use. These inserts can provide alternative cat scratching surfaces. The entire system can be employed in many diverse orientations by hanging it from a wall or door, lying it horizontally on a floor or bracing it diagonally between a floor and wall.

Description:
RELATED APPLICATIONS 
     This is a continuation in part of U.S. application Ser. No. 11/024,399 filed on Dec. 23, 2004. 
    
    
     TECHNICAL FIELD 
     The present invention involves a cat scratching system for providing cat scratching surfaces of various types for use by domestic cats. This system includes a shell having an opening in which various cat scratching surfaces, alone, or in connection with supporting substrates can be inserted. 
     BACKGROUND OF THE INVENTION 
     It is well recognized that domestic cats crave scratching as part of their natural instinctive character. If a dedicated scratching surface is not provided, domestic cats will generally satisfy their need to scratch by turning to furniture, curtains and other articles which can be substantially damaged as a consequence. Often times, pet cats will not only climb over furniture, especially upholstered chairs and sofas, but will use such furniture and carpeting to condition their claws through deliberate and repeated clawing, pulling and tearing actions specifically with their fore paws. As noted, this clawing activity appears to be an irresistible natural impulse for cats and can be the source of great aggravation to the pet owner. 
     A number of vendors of pet and pet related products have offered dedicated scratching posts and surfaces in order to ameliorate this problem. Current devices consist of several alternative designs. A first group of cat scratchers consists of a rigid support covered with a plush surface such as rug or sisal. Such objects are generally in the shape of a post or beam which the cat can climb or otherwise engage during the clawing process. In that the plush surface is bonded to its support, once this surface has been compromised due to the cat&#39;s clawing action, the entire post or block must be discarded in its entirety. 
     Because of the unitary nature of prior cat scratching surfaces, if one wished to present a completely different surface to a cat simply because the cat favored an alternative surface or as a means of adding diversity to the scratching experience, one could not alter such a surface without discarding the entirety of the apparatus while replacing it with an alternative. 
     In addition, corrugated cardboard surfaces have been employed as scratchers. Many cats find cardboard preferable to carpeting as it is a soft material having corrugations that cats seem to enjoy. Also, the corrugated intersities in the cardboard surface can capture catnip thus further enhancing the scratching experience. However, as noted, corrugated cardboard is a relatively soft material which is easily destroyed with even modest cat scratching activity. 
     It is thus an object of the present invention to provide a cat scratcher system which can present different scratching surfaces to a domestic cat without the need to completely replace the entire system in order to do so. 
     A further object of the present invention is to provide a cat scratcher system in which various inserts can be employed to present new scratching surfaces to a pet without changing the entire system by simply changing inserts. 
     It is yet a further object of the present invention to provide a cat scratcher system in which various scratching surfaces can be replaced as they become compromised and worn without having to replace the entire system. 
     It is still a further object of the present invention to provide a cat scratcher system that can be installed and employed on a variety of surfaces, at a variety of angles and that make use of a multitude of attachment schemes. 
     These and further objects will be more readily apparent when considering the following disclosure and appended claims. 
     SUMMARY OF THE INVENTION 
     The present invention involves a cat scratcher system for providing at least one surface suitable for cat scratching. The system comprises an insert having at least one cat scratching surface in a shell. The shell is capable of accepting the insert and is characterized by having a top panel, a bottom panel and side panels, at least one of the panels being provided with an open region for displaying at least one cat scratching surface to the exterior of the shell. Further, at least one of the panels is capable of opening to provide access to the interior of the shell to enable the insert to be removably placed therein. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIGS. 1A ,  1 B and  1 C are prospective views of three suggested embodiments typifying the present invention. 
         FIGS. 2A-2E  are side and end views of shell geometries which typify the myriad of embodiments embracing the present invention. 
         FIGS. 3A and 3B  are bottom plan views showing alternative slip resistant supports for the cat scratcher system of the present invention. 
         FIGS. 4A and 4B  are prospective and bottom plan views of yet another embodiment of the cat scratcher system of the present invention. 
         FIG. 5  is a side plan view showing one of the various attachment protocols while employing the embodiment shown in  FIGS. 4A and 4B  hereof. 
         FIGS. 6A-6C  are top plan views of different embodiments of the cat scratcher system of the present invention. 
         FIGS. 7A-7E  are top plan views showing how multiple cat scratcher modules can be joined to increase the flexibility of the present invention. 
         FIGS. 8A and 8B  are side plan views showing the securing of the cat scratcher system of the present invention in the vicinity of a door as a further illustration of the use of the present invention. 
         FIGS. 9A and 9B  are side and partial side views showing yet another embodiment of the present invention and the incorporation of a swat toy in conjunction therewith. 
         FIGS. 10A-10G  illustrate, in side plan views, various embodiments of inserts for use in the cat scratcher system of the present invention. 
         FIG. 11  is a side plan view of an embodiment of the cat scratcher system of the present invention employed in conjunction with a typical floor and perpendicularly extending wall support. 
         FIG. 12  is a side cross-sectional view of yet a further embodiment of the cat scratcher system of the present invention. 
         FIG. 13  is a perspective view of a further embodiment of the cat scratcher system of the present invention. 
         FIG. 14  is a partial perspective view showing a preferred embodiment of the present invention. 
         FIGS. 15A , B and C are crossectional views illustrating the use of a spacer to insure a snug fit of an insert within the shell of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1A ,  1 B,  1 C and  13  show several iterations of the cat scratcher system of the present invention. Although the geometry of the system can be of any shape,  FIG. 1A  depicts cat scratcher system  10  including a shell having a substantially rectangular top  12  and bottom  29  as well as side panels  30  and  31  extending perpendicularly from top panel  12 . In the embodiment shown in  FIG. 1A , top panel  12  is hinged at seam  13  providing access to the interior of the shell. In this instance, cat scratching insert  14  is shown which can be introduced and removed from the interior of the shell when top  12  is swung open as shown. Hinging can be applied to any seam. For example, see  FIG. 13  where hinge  1303  appears along the long edge of the cat scratcher system. The top of the shell can also be completely removable thus eliminating the need for a hinge altogether. 
     It is an essential component of the present invention to provide an outer shell which can be opened for the introduction of replaceable inserts either to provide a variety of surfaces or to replace cat scratching surfaces as they are worn. However, the present invention is not limited to the introduction of such inserts merely through employment of a removable top surface. Alternatively, as noted in  FIG. 1B , cat scratcher system  101  can be employed wherein end panel  132  can swing through hinge  38  enabling insert  14  to pass within the outer shell bound by top surface  112 , end panels  30  and  31  and bottom panel  29 . 
     Similarly, as noted by reference to  FIG. 1C , insert  14  can be introduced to cat scratcher system  102  by opening side panel  130  through hinge  39 . Although not shown, insert  14  could also be introduced to the outer shell of a cat scratcher system by opening bottom panel  29  as an alternative to those embodiments shown in  FIGS. 1A ,  1 B and  1 C. 
     Once introduced, the outer shell can be closed to secure insert  14  displaying a suitable cat scratching surface to a pet by supporting the cat scratcher system on suction cups or other frictional supports  25  or hung from a doorknob or similar support through the use of rope, cord or plastic handle  5  or by other means discussed hereinafter. Rope, cord or plastic handle  5  can be optionally selectively removable.  FIG. 1A  depicts an example of this by providing key hole slots  4  and corresponding protrusions  3  although other attachment means and attachment locations can be made. 
     Further, although  FIGS. 1A ,  1 B and  1 C show the display of insert  14  only through an opening in the top surface of each shell, the present invention contemplates and thus embraces embodiments where each and every surface, including end panels, side panels or bottom panels, have openings to display suitable cat scratching surfaces. In doing so, a variety of such surfaces can be included in a single insert as discussed hereinafter with regard to  FIGS. 10A-10G  to provide variety, further noting that multiple surfaces will also prevent a single surface from being degraded prematurely. 
     As additionally noted with regard to the embodiments of  FIGS. 1A ,  1 B and  1 C, end panels  32 ,  33  and  132  which extend between top panel  12 / 112  and bottom panel  29  are provided at an angle other than being perpendicular to the top panel and bottom panel. In this embodiment, the end panels ideally extend at an approximately 45 degree angle to the top panel to enable the cat scratcher system to diagonally bridge a horizontal floor and adjoining vertical wall. This embodiment is shown in  FIG. 11  whereby cat scratcher system  1110  is shown diagonally bridging floor  1106  and wall  1105  to present a cat scratching surface  1115 . As such, diagonally extending end panels  1116  and  1117  enable the 45 degree angular relationship between floor  1106 , wall  1105  and cat scratching surface  1115  as illustrated. As a further embodiment, yet again referring to  FIG. 11 , cat scratcher system  1110  can be made to resist slippage from its intended orientation by providing rubber or plastic frictional strips  1120  against flooring  1106 . These strips are shown as an embodiment of the present invention as strips  312  appended to bottom surface  311  of cat scratcher system  310  of  FIG. 3B . 
     There are many alternative configurations for providing frictional elements to the exterior of a cat scratcher system shell in order to accomplish the goals of the present invention. For example, reference is made to  FIG. 14  showing, in perspective, a partial shell having bottom  1401  and diagonally extending end panel  1402 . Suction cups  1404  can be removably appended to key hole openings  1403  configured within bottom panel  1401  and side panel  1402 . These optional suction cups help to keep the system from sliding when placed on a horizontal floor or hung from a vertical surface, such as a door knob. By providing suction cups  1404  as described, a single set of suction cups could be employed taking advantage of the removable feature described herein. This simply adds to the versatility of the present invention while minimizing the number of parts necessary in its implementation. 
     As noted, the shell of the present cat scratcher system can be of any such geometry. One such example of the present invention is shown in  FIG. 13 . 
     Turning to  FIG. 13 , cat scratcher system  1300  is depicted having top  1301  bordering open region  1305  through which a cat scratching surface is made accessible to a pet cat. Top  1301  can be hingedly connected through hinge  1303  to bottom portion  1302 . Alternatively, top  1301  can be a separate part and then selectively removable from bottom  1302 . The shell of cat scratcher system  1300  can be injection molded from a single plastic charge such that hinge  1303  is a “living hinge” contiguous with top  1301  and bottom  1302 . Alternatively, traditional pin hinges can be employed and, as stated previously, top  1301  could be completely removable from the shell to provide access to its interior for insert installation and removal. 
     It is noted that cat scratcher system  1300  employs insert receptacle region  1304  which is substantially rectangular. As such, inserts such as  1010  ( FIG. 10A ) would be ideally suited for use herein. Further, carpet or sisal insert  1020  ( FIG. 10B ) can be situated within insert receiver region  1304  but, in that case, a spacer to maintain a tight frictional fit of the insert within cat scratcher system  1300  would be employed. The use of spacers is further illustrated with respect to  FIG. 15 . 
     It is interesting to note that top  1301  is hingedly connected to bottom  1302  along the lengthwise edge of cat scratcher system  1300 . This further illustrates, in comparison to  FIG. 1A , the myriad of possible ways in which the interior of a cat scratcher system shell of the present invention can be accessed while remaining within the spirit and scope of this disclosure. In addition, the preferred embodiment of  FIG. 13  offers a user a certain degree and convenience not shared by other embodiments disclosed herein. For example, in that insert receiving region  1304  is smaller than the outer perimeter of cat scratching system  1300 , unused regions such as  1306  can act as receptacles for a myriad of useful subparts. For example, cat nip could be applied to area  1306  thus placing the cat nip proximate to any insert placed within insert receiving region  1304  while preventing direct access to the cat nip when top  1301  is closed upon  1302 . Once closed, securing tabs  1308  can engage regions  1309  snap fitting in place thus selectively preventing a cat from gaining access to whatever is in region  1306 . Further, region  1306  could be used to contain attachment hardware used to releaseably append the cat scratcher system to a suitable support. In this regard, reference is made to  FIGS. 4A ,  4 B and  5 . 
     Turning to  FIG. 2 ,  FIG. 2A  depicts a side view of the geometry of the shell of  FIGS. 1A ,  1 B and  1 C by providing shell  201  having top surface  210 , bottom surface  211  and end panels  212  and  213  extending, ideally, at a 45 degree angle from the top and bottom surfaces as illustrated. However, as noted in  FIG. 2B , shell  202 , including top surface  215 , bottom surface  216  and end panels  217  and  218  can be provided in which end panel  217  is perpendicular to top panel  215  and bottom panel  216  while end panel  218  can have substantially the same angular orientation as panel  212  of  FIG. 2A . Such an embodiment can also be used in the orientation depicted in  FIG. 11  whereby end panel  218  would lie against floor  1106  and end panel  217  would simply lean against wall  1105  without being flush thereto. It is important to note that  FIGS. 2A and 2B  are illustrative of simply two geometrical configurations as being examples of the present invention. Certainly, these examples are simply illustrative noting that the various outer surfaces of the shell of the scratcher system of the present invention can take on virtually any suitable shape or orientation while remaining within the spirit and scope of the present invention. 
     Similarly, the sidewalls of the shell of the scratcher system of the present invention can also be configured in a multitude of angular relationships including rounded surfaces creating suitable geometries. In this regard, reference is made to  FIGS. 2C ,  2 D and  2 E which are end views of scratcher systems exemplifying some, but not all of such choices. For example, turning to  FIG. 2C , top surface  220  and bottom surface  221  can be configured substantially parallel to one another while side panels  222  and  223  can angle between these top and bottom surfaces in creating scratcher system  203 . These angular relationships can again, ideally, be at approximately 45 degrees to parallel top and bottom surfaces  220  and  221  to enable cat scratcher system  203  to again bridge a suitable floor and adjoining perpendicular wall while diagonally bridging these surfaces. As noted with regard to  FIG. 2D , cat scratcher surface  204  having substantially parallel top and bottom surfaces  230  and  231  can be connected by perpendicularly extending side panel  232  and angularly extending side panel  233 . Finally, cat scratcher system  205 , shown in  FIG. 2E , can be provided with a box-like perimeter whereby top and bottom surfaces  240  and  241  are connected by perpendicularly extending side panels  242  and  243 . The embodiment of  FIG. 2E  can embrace that embodiment shown in  FIGS. 1A ,  1 B and  1 C. 
     As previously noted,  FIGS. 3A and 3B  are bottom plan views of typical cat scratcher systems of the present invention. Turning first to  FIG. 3A , cat scratcher system  300  having bottom surface  301  is shown with plastic or rubber feet or suction cups  302  which help the present invention from sliding on a supporting surface as a cat engages the cat scratcher system as intended. Suction cups such as supports  302  can support cat scratcher system  300  on a horizontal floor or can act as high friction stabilizing elements when the cat scratcher system is hung vertically from a doorknob or similar support through the use of removable cord  5  ( FIG. 1 ). Such suction cups can also be repositionable or removable altogether as shown in  FIG. 14 . As an alternative, cat scratcher system  310 , having bottom surface  311 , can employ one or more high friction strips  312 . Such strips are particularly advantageous when using the cat scratcher system in the embodiment shown in  FIG. 11 , as discussed previously. Clearly, high friction strips  312  are deployed in the configuration of  FIG. 11  as high friction strips  1120  noting that they ideally bridge a portion of the bottom and side walls of a suitable cat scratcher system or can be applied to only the angled end surfaces if desired. Repositioned suction cups  302  ( 1404  of  FIG. 14 ) can be moved to surface  1116  ( FIG. 11 ) for the same purpose. 
     Turning to  FIGS. 4A and 4B , cat scratcher system  400  is depicted having a top surface  410 , insert  414 , side panels  432  and  433  as well as sloping end panels  430  and  431 . This embodiment depicts yet a further alternative for attaching a suitable cat scratching system to a support structure. As an option, cat scratcher system  400  can be provided with openings  435  for enabling a screw or nail to pass through side wall  432  and into a suitable supporting structure such as wall  440  or even other related products such as self-supporting cat scratching posts. Screw, nail or other attachment means  437  can be anchored to the interior of cat scratcher system  400  by any suitable means such as through the use of a screw with an expanded head region  445  whereby the body of attachment means  437  can pass through opening  435  but not its expanded end  445 . 
     Although the embodiment as depicted in  FIGS. 4A and 4B  show openings  435  configured solely within side wall  432 , similar openings could be created in any of the shell surfaces. In fact, it is contemplated that all of these surfaces could be produced having weakened scored areas where a user could simply employ one&#39;s thumb, a pin or nail to push the scored or weakened areas from their suitable side wall creating an open region equivalent to openings  435  in virtually any of the walls of the shell material to enable the cat scratcher system to be anchored to any suitable support structure, be it a floor, wall or beam. As a further embodiment, reference is again made to  FIG. 13  showing keyhole openings  1307  which are configured within insert receiving region  1304  and thus not visible once a suitable insert is installed therein. Keyhole openings  1307  are familiar to most people in that they are intended to receive a broadened screw head within the larger open region of the keyhole and, once installed, the cat scratcher system can be moved to a small degree so that the expanded screw head passes within the more narrow region of keyhole opening  1307  thus releaseably securing the cat scratcher system to a suitable wall or floor. 
     As most cat owners are well aware, cats often times can become quite agitated and aggressive in using cat scratching pads and similar surfaces, particularly when enhancements such as catnip are employed. Further, some cat scratching surface inserts  14 , such as carpet or sisal, are prone to dislodgement from their exposed open region. As such, to assist in preventing dislodgement of cat scratching insert  14 , various physical embodiments are envisioned for incorporation herein. 
     Specifically, in referring to  FIGS. 6A-6C , cat scratcher system  600  is provided with a top surface  612 , the border of which is intended to extend beyond the periphery of cat scratching insert  14  which assists in preventing dislodgement. In addition, one or more tabs  612  can be configured to extend from border region of top surface  612  to further hold down cat scratching insert  14 . 
     In addition to tabs  613 , other dislodgement-prevention alternatives can be employed. For example,  FIG. 6B  shows cat scratcher system  610  whereby bridge  616  can extend and thus connect opposite edges of top surface  615  to hold cat scratching insert  14  in position. Yet a further alternative is shown in  FIG. 6C  whereby corner pieces  619  can extend diagonally as shown with regard to top surface  618  of cat scratching system  620 .  FIG. 13  also depicts a series of protrusions  1310  molded into top  1301  which embed into an insert and thus help to resist movement. In practice anyone skilled in the art would appreciate the fact that these are a limitless arrangement of tabs and tab locations useful to accomplish the goals of  FIGS. 6A-6C , above. 
     A further embodiment of the present invention is shown in  FIGS. 7A-7E . Referring first to  FIG. 7A , cat scratcher systems  700  and  710  are shown wherein at least one panel of each shell is provided with openings  705  and  706  for receiving bridging means  715 . The positioning of openings  705  and  706  and the size of bridging means  715  are such that cat scratching system  700  and  710  can be releaseably joined to one another in creating unitary cat scratching insert  730  as shown in  FIG. 7B . In doing so, top surfaces  712  and  722  form a planar surface exposing two cat scratching inserts  14 . In demonstrating the flexibility of this embodiment,  FIG. 7C  depicts the joining of the same two cat scratcher systems  700  and  710  along their shorter edges to produce unitary cat scratcher system  750  as shown. Such bridging hardware could also be included within storage region  306  of the cat scratcher system  1300  as depicted in  FIG. 13 . 
     Yet a further example of joining two cat scratcher systems is shown in  FIG. 7E . In this instance, self supporting structure  790  is created by joining cat scratcher systems  791  and  792  along their common edge  793 , shown to be configured at 45° angles to the long axes of each  791  and  792  system. Bridging means  715  can be used as in previously-discussed embodiments and suction cups  302  employed to resist movement of self supporting structure  790  when in use. Cat scratching surface  795  and  796  are thus presented for use by a cat as intended herein. 
     The concept of bridging and thus releaseably joining individual cat scratcher systems to provide multi-unit unitary structures enables a pet supplier to produce a wide variety of creative embodiments. For example, reference is made to  FIG. 7D  whereby unitary structure  760  is shown whereby cat scratcher systems  765 ,  766 ,  767  and  768  are joined by bridging openings  772  in top surface  771 ,  773  in top surface  774 ,  775  in top surface  776  and  777  in top surface  778 . Multiple bridging means  715  can be applied as shown creating a structure having four cat scratcher subsystems, each having its own cat scratching inserts  14  and a central region  780  configured as shown. As an example as to how such a structure could be employed and not intending to limit any particular end use, open region  780  could be provided with a cushioning material such as a pillow or other typical pet bedding surface so that the unitary cat scratcher system  760  can actually function as a pet bed providing not only a comfortable sleeping environment but also cat scratching surfaces as shown. 
     As noted previously with regard to  FIG. 1 , the cat scratcher system of the present invention can employ a number of varying alternatives in securing the system in a predetermined location thus preventing it from inadvertently being dislodged or relocated through aggressive pet-related activities. For example,  FIG. 1  shows the use of removable cord  5  which could engage a doorknob thus enabling the cat scratcher to be hung from a suitable door.  FIGS. 8A and 8B  further illustrate other configurations among the myriad of alternatives which would become quite apparent to those skilled in the art upon reviewing the present disclosure. 
     Turning to  FIG. 8A , cat scratcher system  800  is shown residing on a horizontal floor supported by feet  825 , thus displaying top surface  812  and open region  814  which would enable a cat to gain access to a cat scratching surface (not shown). In order to maintain cat scratcher system  800  in place, cord  805 , appended to an end panel of the cat scratcher system shell can be caused to pass beneath door  820  and suitably connect to doorknob  821  by simply providing a looped end to cord  805 . Once door  820  is closed, the range of movement of cat scratcher system  800  is limited by the length of cord  805 . 
     A further variation to the embodiment shown in  FIG. 8A  is depicted in  FIG. 8B . In this instance, cat scratcher system  800  is shown vertically hung from doorknob  821  using plastic handle, rope or cord  822 . The back surface of cat scratcher system  800  abuts vertically extending door  820  enabling open region  814  to be accessible to an engaging pet. In order to maintain the orientation of cat scratcher system  800 , yet a further cord  823  could be appended to U-shaped bracket  824  as shown. The U-shaped bracket is appended to cord  823  and is sized to slip beneath door  820  and engage door  820  within its U-shaped region. It is noted that cords  822 ,  823  and U-shaped bracket  824  could be provided to a customer when the cat scratcher system  800  was sold. 
     The cat scratcher system of the present invention can also be employed to display other cat attracting devices to enhance a pet&#39;s interest level. For example, reference is made to  FIGS. 9A and 9B  showing cat scratcher systems  900  and  905 . In each instance, top surface  912  and  931 , respectively, are provided with swat toys  920  and  930 . Such toys are common in the pet toy marketplace whereby feathers or similar attractants can be suspended on a support to provide a bouncing movement to the feathers as they are swatted by a playful cat. As shown in  FIG. 9A , such a swat toy could be appended to top surface  912  by use of a simple hook and loop fastener  921 . Alternatively, as shown in  FIG. 9B , a potting material  931  can be supplied beneath the top surface of the cat scratcher system so that swat toy  930  can be extended through this top surface and into potting material  931  as needed. In each instance, the cat scratcher system could be employed without swat toys  920  and  930  and the present invention further contemplates the ability to replace such toys as they degrade through use while maintaining the cat scratcher system as originally provided. 
     Throughout the present discussion, reference has been made to inserts suitable for use in the present cat scratcher systems. All such inserts are related to one another in that each must have at least one textured or porous surface which can present itself through an opening in the shell of the cat scratcher system and be suitable for facilitating cat scratching activity. Such materials include carpet, sisal and corrugated cardboard. Such materials enable a cat to extend its claws and perform its inherent cat scratching activity without harm being inflicted on the cat as a result. Typical inserts for use herein are shown, by example, in  FIGS. 10A-10G . 
       FIG. 10A  shows a solid block of corrugated cardboard  1010 . Such an insert could be installed within any of the cat scratcher systems described above where the top surface of corrugated cardboard block  1010  would be presented as the cat scratching surface. Such a physical embodiment would be ideal for use in cat scratcher system  1300  of  FIG. 13 . As an inherent advantage in practicing the present invention, once corrugated cardboard insert  1010  was abraded through use as a cat scratching medium, it could be removed from the shell of the cat scratcher system and turned upside down to present a fresh surface for continued cat scratching activity. As such, through the use of the present invention, a single insert such as cardboard block  1010  could, in essence, double the life of the replaceable insert without added cost being imposed upon the pet owner. In addition, once both top and bottom surfaces of cardboard block  1010  were sufficiently degraded so that its use as a cat scratching insert was no longer viable, the pet owner could simply purchase a new insert while retaining the outer shell and other elements of the cat scratcher system, thus reducing costs in providing a pet with a continuous, cat scratching medium. 
     As noted previously, an alternative cat scratching surface can constitute carpet or sisal. In this regard, reference is made to  FIG. 10B  where cat scratching insert  1020  is shown. Obviously, if carpet or sisal  1020  was employed solely as a cat scratching medium, the sidewalls of the cat scratcher system would be very shallow to frictionally engage such a relatively thin medium. 
     In order to standardize the depth of the cat scratching system of the present invention and also to add flexibility to the inserts for use herein, reference is made to  FIG. 10C  showing a composite structure. In this example, insert  1030  can be composed of the stacking of carpet or sisal  1020  and cardboard block  1010 . In doing so, the full depth of a standard cat scratcher system could be occupied while providing a carpet or sisal surface to the pet. In addition, insert  1030  could be flipped upside down so that cat scratching surface could constitute either the carpet  1020  or the outer layer of corrugated cardboard block  1010  to provide diverse cat scratching surfaces to engage a pet and take advantage of its natural curiosity. It is also contemplated that the present invention could employ a quantity of catnip within inserts and, in referring once again to  FIG. 10C , such catnip could be placed within the interstices of corrugated cardboard block  1010  while preventing a cat from directly gaining access to it by providing carpet or sisal  1020  as a barrier. The pet would still receive stimulation from the catnip odor emanating from the cat scratcher system of the present invention in this embodiment. 
     In some instances, a user of the present invention may find it beneficial to provide only a carpet or sisal surface to the engaged pet but wishes to do so in the standard cat scratcher system discussed above having a depth great enough to receive significantly sized inserts. For example, carpet or sisal would present a much more durable surface than, for example, a surface of corrugated cardboard. In such an instance, as shown in  FIG. 10D , sisal  1020  could be mounted upon wooden block  1040 , the latter acting only as a spacer and rigid support for the cat scratching surface of carpet or sisal  1020 . 
     Regardless of the composition of any insert for use herein, its geometrical configuration and orientation can be selected among a myriad of choices, none of which limiting the scope and reach of the present invention. For example, turning to  FIG. 10E , insert  1050  having substantially parallel top and bottom surfaces  1051  and  1052  is provided with sloping end walls to fit snugly in, for example, the cat scratcher systems of  FIGS. 1 and 11 . Alternatively, the insert of  FIG. 10F  again having top and bottom substantially perpendicular cat scratching surfaces  1061  and  1062  has one end wall  1064  sloping at, preferably, a 45 degree angle between the top and bottom surfaces and a substantially parallel end wall  1063 . Such insert  1060  could be employed in, for example, the cat scratcher system of  FIG. 1  but, in doing so, ideally, a spacer would be employed to ensure a snug fit between insert  1060  and the outer shell of the cat scratcher system. In this regard, reference is made to  FIG. 12  wherein spacer  1220  is shown within a shell of the cat scratcher system of  FIG. 1 . Spacer  1220  exposes a cat scratching surface through open region  1215 . Sloping sidewall  1210  is intended to abut and be snugly retained by sloping side  32 . However, in this instance, spacer  1225  composed of any suitable material, such as a wooden block, could abut the vertical edge  1222  of spacer  1220 , again, providing a snug fit within the outer shell material. This embodiment illustrates the wide latitude that a user would have in employing inserts of various geometrical dimension into standard shell configurations of the present cat scratcher system. 
     Providing a snug fit between an outer shell and cat scratching inserts is somewhat important in practicing the present invention for cats tend to be quite aggressive in their clawing action as it is a natural tendency on the part of a cat to attempt to pull an insert from the securing shell body. In this regard, reference is made to  FIG. 15A-15C . Specifically, shell  1501  is shown in side cross sectional view having open region  1502  for exposing a suitable insert to a pet. When sold, it is contemplated that a functional insert, such as corrugated block  1503  is situated below a suitably sized cardboard element  1504 . Such a configuration is particularly advantageous as instructions and other consumer related information could be printed directly upon cardboard element  1504  and viewed through opening  1502 . If catnip is placed within the intersities of corrugated insert  1503 , cardboard element  1504  would also prevent the catnip from spilling from the interior of shell  1501 . If no other functional insert other than corrugated block  1503  was employed as a cat scratching medium, cardboard element  1504  could be repositioned below corrugated insert  1503  as shown in  FIG. 15B  to maintain a snug, slip free insert. However, if one wished to place, for example, sisal  1505  above corrugated insert  1503 , cardboard element  1504  could simply be removed as sisal  1505  would occupy space within shell  1501  that was previously occupied by cardboard element  1504  as shown in  FIG. 15C . Also, users may at a later time, employ other inserts that may not be thick enough to occupy the entire shell height. In such instances, the cardboard element can be used to take up interior shell volume. 
     As noted previously, it is contemplated, as a preferred embodiment, that the cat scratcher system of the present invention have the ability to retain catnip or other odor or fragrance emanating sources to enhance the attractiveness of the cat scratching surface. For example, catnip could be embedded within the interstices of a suitable corrugated cardboard insert as such corrugations would be well suited to receive catnip leaves and is porous enough to allow vapors emanating from the catnip to become discernable by the pet employing the present cat scratcher system. As a further embodiment, as shown in  FIG. 10G , a corrugated cardboard insert  1070  having body  1071  could be provided with cutout regions  1072  acting as reservoirs for receiving catnip or other odor emanating fragrances. In such instances, the catnip within reservoirs  1072  would be well separated from the outer cat scratching surface. In addition, as the effects of the catnip dissipate, it would be a relatively easy task to remove insert  1070  while disposing of spent catnip within reservoirs  1072  and replacing it with a fresh supply.