Abstract:
Provided is a multi-configurable feline play structure having a plurality of modular components, modular components, and methods for joining modular components. Tubular frame members are joined by connectors, thereby forming a modular component. Each connector has a plurality of bores, each one of which is adapted to receive an end of a selected frame member. The connectors further connect multiple modular components to form a feline play structure. Flexible web members may be suspended from selected frame members, to form sides. Appurtenance in the form of playthings may be attached at various locations on the play structure such that many modular configuration combinations are available to the pet owner. A kit for a selected modular component may be formed comprising frame members, connectors, flexible webs, and assembly instructions.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The housecat is a popular pet due to its intelligence and personality. An owner&#39;s physical. household and the surrounding yard are shared with the cat and form the cat&#39;s territory. The responsibility attached to cat ownership includes providing the animal with proper nutrition, shelter, and interaction. As a result, various structures have been designed with pet housing or play in mind. Such structures may include an enclosed area which satisfies an animal&#39;s desire to “nest”, with more elaborate structures further including other specified areas, such as play areas with toys, or areas to satisfy an animal&#39;s need to rest, play, climb and watch. 
         [0002]    Such complex playhouse structures seek to combine a layout that is appealing to pets while having design versatility. However, these structures are often difficult to move and/or store, particularly if the structure is large and includes a complex roof design. Furthermore, such structures typically have finite, stagnant configurations that are not able to be reconfigured, modified, or enlarged. 
         [0003]    Accordingly, there is a need for a feline play structure that overcomes the above noted shortcomings. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention satisfies such a need by providing a feline play structure comprised of a plurality of interchangeably connectable modular units and kits, each one of which may be designed to provide a separate function. The user may easily assemble the units and reposition them as desired relative the multi-configurable play structure, with minimal tool use. Each modular unit is designed to provide a distinct function, such providing a nesting area, an amusement area, a lookout perch, a climbing structure, or any other area that may entertain a pet, such as a cat. The versatility of such an interchangeably connectable modular feline play structure provides a practical and inexpensive accessory for owners of such pets to keep them occupied while the owner is away, yet allow for infinite variety of configuration. A customizable, easy-to-assemble, feline playhouse according to the present invention is formed from modular components that may be purchased separately in kit form and assembled by the end user to form an individualized playhouse. Other features, such as toys and scratching posts may be added as well. 
         [0005]    A feline play structure according to the present invention is adapted to be assembled by the user and may be used indoors or outdoors while providing a pet with exercise and playful enjoyment. 
         [0006]    In view of the foregoing background, it is therefore an object of the present invention to provide a play structure for entertaining small animals, the structure having a plurality of interchangeably connectable modular units, each of the units having a configuration to promote a specific animal activity. 
         [0007]    These and other features and advantages of the invention are provided by a play structure including a plurality of interconnecting, interchangeable units which are adapted to be releasably secured to one another. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a perspective view of a feline play structure according to the present invention with a plurality of completed modular structures joined together. 
           [0009]      FIG. 2  is a perspective view of a feline play structure according to the present invention and showing an alternative arrangement of completed modular units joined together. 
           [0010]      FIG. 3  is a perspective view of a nesting type modular unit. 
           [0011]      FIG. 4  is a perspective view of an alternative embodiment nesting type modular unit and showing tab fasteners. 
           [0012]      FIG. 5  is a perspective view of another modular unit to be used with the present invention. 
           [0013]      FIG. 6  is a perspective view of the modular unit illustrated in  FIG. 5 , but showing tab fasteners. 
           [0014]      FIG. 7A  is a perspective view of an embodiment of a connector according to the present invention. 
           [0015]      FIG. 7B  is a side view of the connector shown in  FIG. 7A . 
           [0016]      FIG. 7C  is a cross sectional view of the connector shown in  FIG. 7A  and taken along lines  7 C- 7 C thereof. 
           [0017]      FIG. 7D  is a side view of an alternative connector and showing oppositely disposed, laterally extending collar portions. 
           [0018]      FIG. 8  is an exploded view of the unit illustrated in  FIG. 3  and showing the tubular frame components and connectors. 
           [0019]      FIG. 9  is a perspective view of yet another modular unit to be used with the present invention. 
           [0020]      FIG. 10  is a perspective view of the modular unit illustrated in  FIG. 9 , but showing tab fasteners. 
           [0021]      FIG. 11  is a perspective view of a scratching post unit that may be used with the present invention. 
           [0022]      FIG. 12  is a perspective view of a swat play unit to be used with the present invention. 
           [0023]      FIG. 13  is a perspective view of the disassembled components of the modular unit illustrated in  FIG. 3 , which may be provided in kit form. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0024]    Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims. 
         [0025]    With reference to  FIGS. 1 and 2 , completed feline play structures  10 ,  10 A according to the present invention are illustrated by way of non-limiting example. As viewed particularly in  FIG. 1 , the play structure  10  shown is configured as having a plurality of modular components  20 ,  30 ,  40 . As seen, the modular components  20 ,  30 ,  40  each comprise a plurality of frame members  50 , with modular component  30  having a plurality of curved frame members  50 A (see also  FIG. 5 ). As will be discussed in more detail, the frame members  50  or  50 A are joined by way of connectors  60 ,  60 A, with flexible webs  70  suspended from selected frame members  50 ,  50 A of components  20 ,  30 , and  40 . Webs  70  may be made from any suitable material, such as nylon fabric, or mesh, for example. As shown the Figures, means for suspending the flexible webs  70  from frame members  50 ,  50 A may be way of a sleeve  80  formed in a perimeter of a web  70 , or by other means such as the tab member  90  illustrated in  FIGS. 4 ,  6 , and  10 , or any combination thereof. The tab members  90  shown may be joined to the perimeter of a selected web  70  by sewing or other means, with the tab member  90  being selectively engageable with itself by way of a fastening mechanism  91 , such as the hook and loop fastener shown. 
         [0026]    With reference now to  FIG. 3 , a modular hideaway unit  20  is shown. As illustrated, the modular hideaway unit  20  is designed to provide a hideaway or nesting environment for a selected animal, such as a cat (not shown). The modular hideaway unit  20  preferably comprises a plurality of straight tubular frame members  50 , with the frame members  50  being joined by way of connectors  60 . As discussed earlier, means for suspending the flexible webs  70  may be by way of a sleeve  80  formed in a perimeter of a selected web  70 , or by other means such as the tab members  90  illustrated in  FIG. 4 , or any combination thereof. AS mentioned, the tab members  90  illustrated in  FIG. 4  may be joined to the perimeter of a selected web  70  by sewing or other means, with a selected tab member  90  being selectively engageable with itself by way of a fastening mechanism, such as the hook and loop fastener shown. It is to be understood that a modular hideaway unit  20 ,  20 A may be made having sleeve  80 , tab member  90 , or any combination thereof. 
         [0027]    As may be further seen in  FIGS. 3 and 4 , the modular hideaway unit  20 ,  20 A preferably includes a top panel  21 , a bottom panel  22 , and a plurality of adjacent side panels  23 A,  23 B,  23 C, and  23 D. AS illustrated in  FIGS. 3 and 4 , at least one of the panels  21 ,  22 ,  23 A,  23 B,  23 C,  23 D preferably includes at least one opening  24 . Opening  24  provides access into the hideaway unit  20 ,  20 A to thereby allow an animal to readily travel into and out of the hideaway unit  20 ,  20 A. 
         [0028]    As viewed particularly in  FIG. 4 , the hideaway unit  20 ,  20 A may further include a tubular frame member  50  having a scratching post  26 . Since many cats (not shown) have a habit of standing on their hind legs and using their front paws to scratch any convenient object, the addition of a scratching post as a component of the hideaway unit  20 ,  20 A encourages the cat (not shown) to indulge in its scratching habit, keep its claws in good condition and further encourage exercise through stretching. As illustrated, the scratching post  26  includes a cylindrical frame  27  having an opening  29  therein (see  FIG. 7 ), and an outer covering  28  made of a suitable material. The frame  27  may be adapted to cover and be supported by a selected frame member  50  or alternatively, the cylindrical frame  27  opening  29  may be fit directly to selected connectors  60  or  60 A, such that the scratching post  26  itself may substitute for a frame member  50 . The outer covering  28  may be fabricated from any material that is both appealing to the cat and resistant to the destructive force of scratching. Such material may be sisal or other rug-like material, by way of non-limiting example. Alternatively, and as seen in  FIG. 11 , a play structure according to the present invention may provide a scratching post  26  as a separate play component  92 . Appurtenance in the form of playthings, such as the batting toys  46  shown, may be attached at various locations on the hideaway unit  20 ,  20 A. 
         [0029]    With reference now to  FIGS. 5 and 6 , a modular climbing hill unit  30  is shown. As illustrated, the modular climbing hill unit  30  is designed to provide a climbing environment for a selected animal, such as a cat (not shown). The modular climbing hill unit  30  preferably comprises a plurality of straight tubular frame members  50  and a plurality of curved frame members  50 A, with the frame members  50 ,  50 A being joined by way of connectors  60 ,  60 A. As discussed earlier, and as shown in  FIGS. 5 and 6 , means for suspending the flexible webs  70  from frame members  50 ,  50 A may be by way of a sleeve  80  formed in a perimeter of a web  70 , or by other means such as a tab member  90 , or any combination thereof. As in the modular unit  20 ,  20 A illustrated in  FIGS. 3 and 4 , the tab members  90  illustrated in  FIGS. 5 and 6  may be joined to the perimeter of a selected web  70  by sewing or other means, with the tab member  90  being selectively engageable with itself by way of a fastening mechanism, such as the hook and loop fastener shown. It is to be understood that a modular climbing hill unit  30  may be made having a sleeve  80 , tab member  90 , or any combination thereof, as a web suspension means. 
         [0030]    As may be further seen in  FIGS. 5 and 6 , the modular climbing hill unit  30  preferably includes a curved top panel  32 , suspended by curved frame members  50 A, and at least one side panel  34 . It is to be understood that while the Figures depict a modular climbing hill unit  30  having one side panel  34 , any number of side panels  34  may be provided without departing from the spirit of the invention. A bottom panel (not shown) may also be provided, depending on the vagary of the end user. Similar to the previously described hideaway unit  20 ,  20 A, a climbing hill unit  30  may further include a tubular frame member  50  having a scratching post  26 . As discussed earlier, since many cats (not shown) enjoy using their front paws to scratch any convenient object, the addition of a scratching post as a component of the climbing unit  30 ,  30 A encourages a cat (not shown) to indulge in its scratching habit, keep its claws in good condition and further encourages exercise through stretching. As previously seen, and as illustrated in  FIG. 6 , the scratching post  26  includes a cylindrical frame  27  having an opening  29  therein (see  FIG. 7 ), and an outer covering  28  made of a suitable material. The frame  27  may be adapted to cover and be supported by a selected frame member  50  or alternatively, the cylindrical frame  27  opening  29  may be fit directly to selected connectors  60  or  60 A, such that the scratching post  26  may substitute for a frame member  50 . The outer covering  28  may be any material that is both appealing to the cat and resistant to the destructive force of scratching. Such material may be sisal or other rug-like material, by way of non-limiting example. 
         [0031]    As mentioned with regard to the hideaway unit  20 ,  20 A, the modular climbing hill unit may also be provided with appurtenance in the form of playthings, such as the batting toy  46 , shown. It is to be understood that the playthings may be in any form attractive to felines. 
         [0032]      FIGS. 7A ,  7 B,  7 C, and  7 D provide a connector  60 ,  60 A, which may be formed in several desirable shapes, but is preferably formed generally in the shape of a compact cylinder having a top surface  61 , a bottom surface  62 , and a peripheral edge surface  63 . As seen, a connector  60 ,  60 A includes a central axis  64  extending from the top surface  61  to the bottom surface  62 . The connector  60 ,  60 A may further include an axially extending inner bore  65  adapted to receive an end  52  of a selected tubular frame member  50 ,  50 A in opening  66 . As seen, the bore  65  may be disposed preferably coaxially and extending from the top surface  61  to the bottom surface  62  of the connector  60 ,  60 A, and include at least one bore opening  66 . The bore  65  preferably has a relatively uniform diameter and includes inner surfaces  67  adapted to retain an end  52  of a selected frame member  50 ,  50 A therein. As may be observed in  FIGS. 7A-7D , the bore  65  may be extended by way of a laterally extending collar portion  68  that defines a substantially cylindrical, close-fitting channel  65 A adapted to receive an end portion  52  of a selected tubular frame member  50 ,  50 A therein. For greater flexibility in construction, and as seen in  FIG. 7D , the bore  65  may include a pair of oppositely disposed, laterally extending collar portions  68 ,  68 A. Use of a connector  50 A as seen in  FIG. 7D  permits further connectivity options, such as may be observed in  FIGS. 1 and 2 . 
         [0033]    As further seen in  FIGS. 7A-7D , a connector  60 ,  60 A according to the present invention may include a bore  65  having a first opening  66  and a second, oppositely disposed opening  66  having a diameter consistent with the first opening, as shown in  FIG. 7D . Alternatively, a connector  60  may have a first opening  66  having a first diameter, and a second, coaxial opening  66 A having a second, smaller diameter. It may be observed that a connector  60  including a second coaxial opening  66 A having a second, smaller diameter, further thereby provides a ledge  69 . The ledge  69  serves to limit longitudinal movement of an inserted tubular frame member  50 ,  50 A, to thereby ensure proper fit and alignment of the various components during assembly of a selected modular component  20 ,  30 ,  40 . Connectors  60  having this configuration may be used when a flat bottom surface  62  is desired, as for example when the bottom surface  62  is to be placed on the floor (not shown). The second opening  66 A may further be used to support any number of feline playthings, including the batting toy  46 , seen in phantom in  FIG. 3 , by way of non-limiting example. 
         [0034]    As may be further observed with reference to  FIGS. 7A-7D , a connector  60 ,  60 A according to the present invention further includes a peripheral edge surface  63 . The edge surface  63  may be provided with one or more radially extending bores  72 . The radially extending bores  72  are preferably adapted to receive an end portion  52  of a selected frame member  50 ,  50 A. While a connector  60 ,  60 A according to the present invention may include any practical number of bores  72 , a preferred number is four, wherein the spacing between adjacent bores  72  is approximately  90  degrees. This spacing permits the most accurate spacing of frame members and allows convenient connection of adjacent modular units  20 ,  30 ,  40 ,  40 A, for example. As seen, an interior surface  74  of each bore  72  includes at least one raised area  76  that preferably comprises an inwardly directed, raised ridge  78  that compresses against the exterior  54  of an end  52  of a tubular frame member  50 ,  50 A when the end  52  is inserted in the bore portion  72 . Preferably, the height of the ridges  78  is sufficiently great to ensure that they will engage the exterior surface  54  of the end  52  of the tubular frame member  50 ,  50 A, given the expected variations in frame member  50 ,  50 A dimension and the manufacturing tolerances of the connector  60 ,  60 A. As best seen in  FIGS. 7A and 7C , the ridges  78  simply contact and slightly deform the frame member  50 ,  50 A to a greater or lesser degree as needed to ensure a snug fit within the bore  72 , regardless of minor variations in the actual clearance between a selected connector  60 ,  60 A and a selected frame member  50 ,  50 A. Preferably, one or more ridges  78  are formed on the interior surface  74  of each bore  72 . 
         [0035]    With particular reference to  FIG. 7C , each radially extending bore  72  is further preferably provided with a proximal end  82  and a distal end  84 , with the distal end  84  including an upstanding annular shoulder  86 . Upstanding annular shoulder  86  limits longitudinal movement of a selected frame member  50 ,  50 A as its end  52  is positioned within the bore  72 . In this manner, each frame member  50 ,  50 A is automatically directed into proper axial alignment with the connector  60 ,  60 A as it is inserted into the bore  72 . 
         [0036]    The connectors  60 ,  60 A are preferably formed of, or molded from, a polymeric material with some rigidity, such as plastic. Preferably, the connector structure  60 ,  60 A is integrally formed, and the connector  60 ,  60 A is molded as a unitary structure in a single manufacturing step. The connector  60 ,  60 A may be provided with strengthening ribs  88  for added rigidity, if desired. 
         [0037]    Turning now to  FIG. 8 , an exploded view of the modular hideaway unit  20 A is shown to thereby illustrate the manner in which the cooperating components of a selected modular unit may be assembled and connected with other modular units to form a completed play structure  10 . 
         [0038]    First, a selected frame member  50 ,  50 A is slidingly received into a sleeve  80  on web  70 . As seen, at least one connector  60 ,  60 A is provided to facilitate the interconnection of the various frame members. As previously mentioned, each connector  60 ,  60 A preferably includes at least one axially extending inner bore  65  adapted to receive an end  52  of a selected tubular frame member  50 ,  50 A in opening  66 . Each connector  60 ,  60 A may further include peripheral edge surface  63  provided with one or more radially extending bores  72  also adapted to receive an end portion  52  of a frame member  50 ,  50 A. A selected end portion  52  of frame member  50  is inserted into a selected bore  65  or  72  of a connector  60 ,  60 A. Multiple frame members  50 ,  50 A are assembled in this manner to form the desired modular structure  20 ,  30 ,  40 . With further reference to  FIG. 8 , the manner by which multiple modular components  20 ,  30 ,  40  may be interconnected to form a completed play structure may be seen in phantom. In a manner similar to that of an individual modular structure  20 ,  30 ,  40 , the assembled or partially assembled modular structures may be connected to form a feline play structure comprised of a plurality of interchangeably connectable modular units. As illustrated, selected frame members  50 ,  50 A of an adjacent modular unit  20 ,  30 ,  40  are coupled via connectors  60 ,  60 A 
         [0039]    Referring now to  FIGS. 9 and 10 , a modular lookout unit  40  is shown. As illustrated, the modular lookout unit  40  is designed to provide an elevated location for a selected animal, such as a cat (not shown). The modular lookout unit  40  preferably comprises a plurality of straight tubular frame members  50 , with the frame members  50  being joined by way of connectors  60 ,  60 A. As discussed with regard to modular units  20  and  30 , means for suspending flexible webs  70  from the frame members  50  may be by way of a sleeve  80  formed in a perimeter of selected webs  70 , or by way of tab members  90 . The tab members  90  illustrated in  FIG. 10  may be joined to the perimeter of a selected web  70  by sewing or other means, with the tab member  90  being selectively engageable with itself by way of a fastening mechanism  91 , such a hook and loop fastener. It is to be understood that a modular lookout unit  40  may be made having sleeve  80 , tab member  90 , or any combination thereof. 
         [0040]    As may be further seen in  FIGS. 9 and 10 , the modular lookout unit  40  preferably includes at least a top panel  42 , although it is within the scope the of the embodiment to include any number of side panels (not shown) without departing from the spirit of the invention. A bottom panel (not shown) may also be provided, depending on the configuration desired by an end user. As in the previously discussed modular units  20 ,  20 A,  30 , and  30 A, the lookout unit  40 ,  40 A may further provide a selected tubular frame member  50  with a scratching post  26  (see  FIG. 9 ), or simply replace a frame member  50  with a scratching post  26 . The lookout unit  40 ,  40 A may be optionally provided with any number of appurtenances in the form of feline playthings, including the rod  44  and batting toy  46  or batting toy on string  46  (seen in phantom), by way of non-limiting example. 
         [0041]    With reference to  FIG. 11 , modular play unit  92  is shown. As illustrated, the modular play unit  92  is designed to provide a scratching and play location for a selected animal. The modular play unit  92  preferably comprises a plurality of straight tubular frame members  50 , with the frame members  50  being retained in radially extending bores  72  of connector  60 . The frame members  50  are further retained on a support surface  93  by way of sleeves  80 . The support surface  93  may retain the frame members  50  thereon by way of a sleeve  80  formed on the planar surface of the support surface  93 . Alternatively, the frame members  50  may be retained on the support surface  93  by way of tab members  90  (not shown in these views). As previously discussed with reference to modular units  20 ,  20 A,  30 , and  30 A, the tab members  90  may be joined to the planar surface support surface  93  by sewing or other means, with the tab member  90  being selectively engageable with itself by way of a fastening mechanism, such a hook and loop fastener. As may be further seen, the support surface  93  may include at least one sleeve  80  on peripheral edge  56 . Providing the support surface  93  with a sleeve  80  on a peripheral edge  56  provides means for attaching the modular play unit  92  to a selected adjacent unit  20 ,  30 ,  40 . 
         [0042]    With further reference to  FIG. 11 , the modular play unit  92  preferably includes at least one planar support surface  93 , although it is within the scope the of the embodiment to include any number of support panels (not shown) without departing from the spirit of the invention. As seen, a play unit  92  includes a scratching post  26  upstanding from the support surface  93 . Similarly to those previously discussed, the scratching post  26  shown in  FIG. 11 , includes a cylindrical frame  27 , and an outer covering  28  made of a suitable material, with frame  27  being adapted to receive a laterally extending collar portion  68  of a connector  60 ,  60 A to thereby be supported thereon. Radially extending bores  72  of connector  60  each receive an end portion  52  of selected frame members  50 , with the frame members  50  being further retained by sleeves  80  on support surface  93 . The play unit  92  may be optionally provided with any number of feline playthings,  48  (seen in phantom), by way of non-limiting example. 
         [0043]    With reference now to  FIG. 12 , a modular swat play unit  94  is shown. As illustrated, the modular swat play unit  94  is designed to provide scratching and active play for a selected animal. The modular swat play unit  94  preferably comprises a disc-like track structure  95  adapted to receive and retain a ball  96  (shown in phantom). The structure  95  is further adapted for suspension from the frame members  50  of a selected adjacent modular unit  20 ,  30 ,  40  by way of the curved tab members  97  shown in phantom, or any structure adapted to engage selected frame members  50 . The curved tab members  97  illustrated in  FIG. 12  may be joined to the structure  95  by looping through apertures  98 , with the curved tab member  97  being selectively engageable with itself by way of a fastening mechanism, such as a hook and loop fastener. 
         [0044]    As may be further seen in  FIG. 12 , the modular swat-play unit  94  preferably includes a relatively planar top surface  99  having at least a portion thereof comprised of a scratching surface  28 . Scratching surface  28  is preferably of similar composition to that described with regard to the scratching post  26 , and is adapted for feline scratching or other play and is made of a suitable material that is both appealing to the cat and resistant to the destructive force of scratching. Sisal or other rug-like material is preferred. 
         [0045]      FIG. 13  depicts disassembled modular structure component parts, which may be provided in kit  100  form for assembly. Dependent on the desired modular unit  20 ,  30 ,  40  to be assembled, a kit  100  may include a plurality of frame members  50 ,  50 A, a plurality of connectors  60 ,  60 A, and at least one web member  70 . While kits  100  for assembly of other modular units herein described are not specifically illustrated, it is anticipated that any unit previously described may be provided in a kit form for assembly by the user. It is envisioned that any number of kits  100  may be purchased separately for assembly and interconnection with one another for creation of a feline play structure  10 ,  10 A 
         [0046]    A method according to the present invention includes providing a kit  100 . The kit includes a plurality of frame members  50 , a plurality of connectors  60 ,  60 A, and at least one web member  70 . Dependent on the desired final modular unit  20 ,  30 ,  40 , to be assembled, a kit  100  may further include curved frame members  50 A. The frame members  50 ,  50 A are coupled to each other by way of the connectors  60 ,  60 A to form the desired modular component  20 ,  30 ,  40 . Dependent on the desired final modular unit, the kit may be provided with multiple flexible webs  70 , which are adapted to be suspended from a selected frame member  50 ,  50 A to form a selected panel  21 ,  22 ,  23 A,  23 B,  23 C,  23 D,  32 ,  34 , or  42 . A feline play structure  10 ,  10 A may then be formed by positioning selected, assembled modular units  20 ,  30 ,  40  adjacent one another and coupling them to one another by way of adjacent connectors  60 ,  60 A. To do so, the provided connectors  60 ,  60 A and their bores  65  engage the ends  52  of the frame members  50 ,  50 A of selected modular units  20 ,  30 ,  40  to thereby connect multiple modular units  20 ,  30 ,  40  adjacent one another to form a cohesive play structure  10 . 
         [0047]    In this manner a feline play structure  10  may be enlarged or reconfigured by simply connecting additional modular units  20 ,  30 ,  40  to one another so that a larger or alternatively configured structure  10  is provided. 
         [0048]    The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.