Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims priority from U.S. Provisional Patent Application Ser. No. 61/873,411 entitled “Toy Racetrack Having Collapsible Loop Portion,” filed with the United States Patent and Trademark Office on Sep. 4, 2013 by the inventors herein, the specification of which is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to toy racetracks, and more particularly, to a racetrack for toy vehicles having a track portion that reconfigures the toy vehicle path as a result of a toy vehicle passing over such track portion. 
     BACKGROUND 
     Toy racetracks are popular among children of varied ages, and a variety of track configurations have previously been provided that include various features, such as traps, loops, stunts, and the like to add to the excitement a child experiences while playing with the toy. For instance, toy racetracks have been provided having varied loops and turns that may form complex pathways for the toy vehicle, as well as varied obstacles or stunt devices that the toy vehicle must successfully traverse in order to continue through the racetrack path. 
     For example, U.S. Pat. No. 4,575,350 to Hippely et al. discloses a toy racetrack having a snake head at the end of the track, the snake head including a flexible, rolled tongue. As a toy vehicle impacts the rolled tongue, it will unroll the tongue and continue along its path only if it has enough energy at that time to fully unroll the tongue. 
     U.S. Pat. No. 6,358,112 to Lambert et al. discloses a toy racetrack having a stunt loop portion with a movable creature head on the inner portion of the loop, which movable creature head will move from a toy vehicle non-capture position to a toy vehicle capture position based upon the amount of energy that is transferred to the loop from a toy vehicle as it traverses the loop. 
     U.S. Pat. No. 7,628,674 to Nuttall et al. discloses a toy racetrack having moveable track segments that vary position through an indexing mechanism that operates in response to a toy vehicle travelling through the racetrack. 
     U.S. Patent Publication No. 2005/0287919 of Sheltman et al. discloses a toy racetrack having a swinging traveler that captures a toy vehicle as it travels through the racetrack, and rotates about a support until it aligns with a subsequent section of track, after which it releases the toy vehicle to continue its travel through the racetrack. 
     U.S. Patent Publication No. 2012/0164914 of O&#39;connor et al. discloses a toy racetrack having a variety of track segments that change position as a toy vehicle traverses those segments. 
     U.S. Patent Publication No. 2012/0322342 of De La Torre discloses a toy racetrack having a swinging and spinning toy vehicle support that intercepts a toy vehicle as it travels through the racetrack, and thereafter swings and spins to a new position that releases the toy vehicle onto a subsequent track section. 
     While the foregoing configurations do provide varied obstacle and stunt features, there remains an ongoing need to provide toy racetrack features capable of maintaining the interest of a child and increasing the excitement and amusement they experience when playing with a toy racetrack. It would therefore be advantageous to provide a toy racetrack that further enhances the excitement and amusement offered to a child as they engage in such play. 
     SUMMARY OF THE INVENTION 
     In accordance with certain aspects of an embodiment of the invention, disclosed is a toy racetrack that includes a partial loop section configured to maintain a partial loop configuration when maintained in an unloaded state (i.e., when freestanding in a partial loop configuration without a toy vehicle passing over the partial loop section), and that collapses when in a loaded state in which a toy vehicle passes over such partial loop section. The partial loop section comprises a series of hingedly connected, arcuate track segments. Each arcuate track segment stacks on top of the previous track segment to form a pathway for a toy vehicle, such as a die cast car, which pathway curves upwardly. A hinged stand on the opposite surface of the segment from the pathway may be configured to prop up the vertically arcuate track segment pathway. A sufficient number of arcuate track segments are provided so that the pathway preferably begins to curve back over itself. The partial loop portion is preferably configured so that the center of gravity of the series of segments lies approximately over the location at which the stand props up the segments, thus allowing the vertical segments to “balance” and maintain a free-standing, partial loop configuration. In this configuration, when a force is applied to the upper section of the pathway, such as a force resulting from a vehicle travelling along and up to the upper section of the pathway, the added force shifts the center of gravity past the balancing point, and the partial loop section collapses. 
     In accordance with further aspects of an embodiment of the invention, a preferably ornamental head, such as a faux snake head, may be provided at the terminal end of the upper portion of the partial loop section. The head may be spring-loaded with a trigger, which trigger may optionally be configured as a tongue for the creature whose head is represented, with the tongue aligning with the end of the vehicle path. The spring is loaded upon connection with the terminal arcuate track segment in the partial loop section, and contact with the trigger (such as by a vehicle travelling along the pathway coming into contact with the trigger) releases the spring and causes the head to spring away from the “body” of the creature (such “body” being represented by the remainder of the partial loop section). In certain embodiments, a wind-up motor may drive a diverter in the base of the partial loop section, which diverter may be disguised as a “tail” of the creature, and may move from a first position that will direct a toy vehicle through the partial loop section, to a second position that will direct a toy vehicle away from the partial loop section and onto an alternative racetrack path. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The numerous advantages of the present invention may be better understood by those skilled in the art by reference to the accompanying drawings in which: 
         FIG. 1 a    is a side perspective view of a toy racetrack in accordance with certain aspects of an embodiment of the invention. 
         FIG. 1 b    is a side perspective view of a toy racetrack in accordance with further aspects of an embodiment of the invention. 
         FIG. 2  is a side view of a partial loop section of the toy racetrack of  FIG. 1   b.    
         FIG. 3  is a side, top perspective view of the partial loop section of  FIG. 2 . 
         FIG. 4  is a side, rear perspective view of an arcuate track segment for use in the partial loop section of  FIG. 2 . 
         FIG. 5  is a side, rear perspective view of the partial loop section of  FIG. 2 . 
         FIG. 6  is a front, top perspective view of the partial loop section of  FIG. 2  in a collapsed condition. 
         FIG. 7  is a side perspective view of a portion of the partial loop section of  FIG. 2 . 
         FIG. 8  is a bottom, side perspective view of the ornamental head of  FIG. 7 . 
         FIG. 9  is a bottom, rear perspective view of an ornamental head for use with the partial loop section of  FIG. 2 . 
         FIG. 10  is a bottom view of the ornamental head of  FIG. 9 . 
         FIG. 11  is a rear view of the ornamental head of  FIG. 9 . 
         FIG. 12  is a perspective view of a head carrier receiver for use with the ornamental head of  FIG. 9 . 
         FIG. 13  is an exploded view of the head carrier receiver of  FIG. 12 . 
         FIG. 14  is a top view of a receiver block housing. 
         FIG. 15  is a bottom perspective view of a portion of the ornamental head of  FIG. 9 . 
         FIG. 16  is a top view of a head carrier at a terminal arcuate track segment of a partial loop section of a toy racetrack. 
         FIG. 17  is a side perspective view of the head carrier of  FIG. 16 . 
         FIG. 18  is a front view of the head carrier of  FIG. 16 . 
         FIG. 19  is a perspective view showing insertion of a head carrier into a receiver block housing. 
         FIG. 20  is a perspective view showing a head carrier fully inserted into a receiver block housing. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description is of a particular embodiment of the invention, set out to enable one to practice an implementation of the invention, and is not intended to limit the preferred embodiment, but to serve as a particular example thereof. Those skilled in the art should appreciate that they may readily use the conception and specific embodiments disclosed as a basis for modifying or designing other methods and systems for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent assemblies do not depart from the spirit and scope of the invention in its broadest form. 
       FIG. 1 a    provides a perspective view of a toy racetrack (shown generally at  10 ) in accordance with certain aspects of an embodiment of the invention. As shown in  FIG. 1 , toy racetrack  10  includes a section of track  12 , such as an extruded plastic track configured for use with die cast cars, and a collapsible partial loop section  20  attached to the end of track  12 . Collapsible partial loop section  20  is comprised of multiple arcuate track sections  22  that are hinged to one another (and freely pivoting with respect to one another) along their leading edges. The arcuate track sections  22  are each configured to stack on top of the previous track segment to form an upwardly curving pathway for a toy vehicle. The arcuate track sections  22  are positionable with respect to one another to form a partial loop that extends upward from track  12  and that ends at the top region of the partial loop, such that the partial loop begins to curve back over itself. When the arcuate track sections are so positioned to form the partial loop, the center of gravity of the resulting partial loop is positioned so as to allow the multiple arcuate track segments  22  to balance and maintain the partial loop configuration. A stand  23  may be positioned on the back side of partial loop section  20 , which stand  23  may be positioned to help prop up the arcuate track sections  22  into the partial loop, but which is configured to collapse under the arcuate track segments when the partial loop begins to collapse. Thus, when a force is applied to the upper section of the partial loop, such as a force resulting from a toy vehicle travelling through toy racetrack  10  and up to the upper section of the partial loop, the added force shifts the center of gravity of the partial loop past the balancing point, in turn causing the arcuate track sections  22  to fall and collapsing the partial loop. 
     In some embodiments, a launching member  24  is provided at the free end of the partial loop section, with at least a portion of the launching member  24 , such as an underside of the launching member  24 , being in line with the path of travel of a toy vehicle as it traverses and ultimately exits the partial loop section  20 . Launching member  24  may include a trigger  26  extending into the pathway of the toy vehicle, and may be configured so that in response to a toy vehicle striking trigger  26 , launching member  24  may be dislodged from partial loop section  20 . To aid in the release and launch of launching member  24  from the partial loop section  20 , launching member  24  may be spring biased, with activation of trigger  26  causing an internal spring (not shown) to launch lunching member  24  away from the free end of partial loop section  20 , just as partial loop section  20  is collapsing. 
       FIG. 1 b    provides a perspective view of a toy racetrack (shown generally at  100 ) in accordance with further aspects of an embodiment of the invention. As shown in  FIG. 1 b   , toy racetrack  100  includes a toy vehicle (such as a die cast metal car) launcher assembly  110 , a section of extruded plastic track  120  attached to launcher assembly  110  so as to receive and guide a toy vehicle as it is launched from launcher assembly  110 , and a collapsible partial loop section  200  attached to the end of plastic track  120  opposite launcher assembly  110 . Launcher assembly  110  includes a spring-loaded launch member  112  configured to launch a toy vehicle onto track  120  when triggered by a user, thus directing the toy vehicle across track  120  and towards collapsible partial loop section  200 . A suitable launcher assembly  110  for use with the toy racetrack  100  is described in detail in co-owned U.S. Pat. No. 8,298,035, the specification of which is incorporated herein by reference in its entirety. 
     Collapsible partial loop section  200  is comprised of multiple arcuate track sections  202  that are hinged to one another (and freely pivoting with respect to one another) along their leading edges, and may be positioned with respect to one another to form a partial loop that extends upward from the surface on which launcher  110  and track  120  are situated, and that ends at the top region of the partial loop, such that the partial loop begins to curve back over itself. A stand  204  may be positioned on the back side of partial loop section  200 , which stand  204  may be positioned to help prop up the arcuate track sections  202  into the partial loop. When the arcuate track sections are so positioned to form the partial loop, the center of gravity of the resulting partial loop preferably lies approximately over the stand  204 , allowing the multiple arcuate track segments  202  to balance and maintain the partial loop configuration. However, when a force is applied to the upper section of the partial loop, such as from a toy vehicle travelling through toy racetrack  100  and up to the upper section of the partial loop, the added force shifts the center of gravity of the partial loop past the balancing point, in turn causing the arcuate track sections  202  to fall and collapsing the partial loop. 
     In certain embodiments of the invention, an ornamental head member  206  (shown as the head of a snake in  FIG. 1 , with the multiple arcuate track sections  202  resembling the body of the snake) may be attached to the free end of collapsible partial loop section  200 , and may be configured to disconnect from the rest of collapsible partial loop section  200  when impacted by a toy vehicle travelling through the partial loop. Moreover, ornamental head member  206  may be spring-loaded, having a trigger that when impacted by a toy vehicle releases the spring and causes the head member  206  to spring away from partial loop section  202 . 
     With reference to the exemplary embodiment shown in  FIGS. 2-4 , collapsible partial loop section  200  extends upward from a base  220  to which track sections  202  connect. Base  220  may include a first connection tab  222  configured to receive plastic track  120 , and a second connection tab  224  configured to receive additional sections of plastic track  120 , the purpose of which will be further detailed below. A diverter  226  is hingedly mounted at pivot connection  229  ( FIG. 3 ) to base  200  and is moveable so as to provide a first toy vehicle path  228 , which directs a toy vehicle coming from launcher assembly  110  and across plastic track  120  into the partial loop section  200 , and a second toy vehicle path  230 , which directs such a toy vehicle away from partial loop section  200  and to additional sections of plastic track (not shown). Such additional sections of plastic track may be attached to a further track connection tab  232  situated at the end of toy vehicle path  230  on base  220 . A guide pin (not shown) may extend downward from diverter  226  and may ride within a guide path opening  227  cut across toy vehicle paths  228  and  230 . Diverter  226  may be manually moveable between the two positions to establish the toy vehicle path with which the user wishes to play, or alternatively may be automated to move between the two positions. For instance, a wind-up motor  234  may be provided that, when wound by a user, causes diverter  226  to move between the two positions, thus creating a challenge for the user to time the launch of their toy vehicle so that it engages the desired toy vehicle path  228  or  230  when such toy vehicle reaches base  220 . 
     In order to assist in guiding a toy vehicle as it travels through path  228 , the side of diverter  226  that faces toy vehicle path  228  preferably forms a generally straight line that extends parallel to a sidewall  244  on the opposite side of path  228 . Likewise, in order to assist in guiding a toy vehicle as it travels through path  230 , the side of diverter that faces toy vehicle path  230  preferably forms a curved wall to smoothly turn the toy vehicle towards path  230 . Moreover, diverter  226  may be provided in the shape of a tapering tail of an animal depicted by ornamental head member  206 , such as (in the exemplary case shown in the Figures) the tail of a snake. 
     Those of ordinary skill in the art will recognize that more or fewer intermediate arcuate track sections  202  than what are shown in the Figures may be provided without departing from the spirit and scope of the invention. 
     As mentioned briefly above, arcuate track sections  202  may be positioned to form partial loop section  200 , as they are hingedly connected to one another along their leading edges. A first such arcuate track section  202 ( a ) is hingedly mounted to base  220  at a hinge pin  203 , and may be positioned above second connection tab  224  with sufficient clearance so as to allow insertion of a section of plastic track onto connection tab  224  between the bottom of arcuate track section  202 ( a ) and the play surface on which toy racetrack  100  is positioned. Additional arcuate track sections  202 ( b )- 202 ( g ) are provided, each being hinged to its adjacent track section(s), such that each arcuate track section may pivot with respect to its adjacent track section(s). To foster such pivoting movement between adjacent track sections, and with particular reference to  FIG. 4 , each arcuate track section  202  has at a first end a first segment of a hinge joint, and at a second end a second segment of a hinge joint, which first and section sections mate with one another and receive a hinge pin therethrough to provide a hinged joint. For example, arcuate track section  202 ( c ) shown in  FIG. 4  has first hinge segment  240 ( a ) and  240 ( b ) affixed to the underside of track section  202 ( c ) at its first end (such first end being the end of the respective track segment  202  that is furthest from launcher assembly  110 ), and adjacent arcuate track section  202 ( d ) has second hinge segment  242  affixed to the underside of track section  202 ( d ) at its second end (such second end being the end of the respective track segment  202  that is closest to launcher assembly  110 ). As shown in the close-up view of  FIG. 4 , each arcuate track segment  202  has side walls  244  extending upward from the track surface of each track segment  202  on which a toy vehicle rides, which side walls  244  help to guide the toy vehicle through partial loop section  200 . An upper edge  245  of adjacent side walls  244  of adjacent arcuate track segments  202  ultimately come in contact with one another at their respective wall edges as adjacent arcuate track segments  202  are pivoted toward one another, thus limiting the extent to which adjacent track segments  202  may pivot toward one another. Moreover, as the track segments  202  are manipulated to form partial loop section  200 , the arcuate track segments  202  stack atop one another along their facing wall edges, with a terminal, upper most arcuate track segment  202 ( g ) pointing back toward launcher assembly  110 , such that the partial loop section begins to curve back over itself. In order to allow adjacent track segments to pivot toward one another, the edges of side walls  244  preferably are oriented at less than 90° to the track surface at the end of the track segment, thus allowing adjacent walls to come into contact after two adjacent track segments are pivoted toward one another. 
     As shown in  FIGS. 1-5 , stand  204  is hingedly attached to the underside of partial loop section  200 . With particular reference to  FIGS. 2, 4, and 5 , stand  204  may include legs  205  that extend away from the underside of partial loop section  200 . A top portion  207  of each leg  205  has a hole extending therethrough, which hole receives a hinge pin that likewise extends through hinge segments  240  and  242  on the adjacent arcuate track segments  202  to which leg  204  is attached. A spacer bar  206  runs between legs  205 , and is positioned a sufficient distance from the free ends of legs  205  (i.e., the ends opposite top portion  207 ) so that when leg  204  is positioned to prop up partial loop section  200 , a sufficient clearance exists below horizontal spacer bar  206  so that an additional plastic track section may run beneath stand  204 . 
     Top portion  207  of stand  204  is preferably configured so as to limit the extent to which stand  204  may pivot with respect to partial loop section  200 . More particularly, and with specific reference to  FIG. 2 , stand  204  may be positioned with legs  205  extending down from the underside of partial loop section  200  and away from base  220 , but only to a limit position. Thus, as a toy vehicle initially enters into partial loop section  200 , stand  204  will not collapse but instead will continue to assist in holding partial loop section  200  in its upright configuration. However, as the toy vehicle traverses partial loop section  200  and approaches the top end of partial loop section  200  so as to shift the center of gravity as discussed above, the partial loop section  200  collapses, and as it collapses causes stand  204  to fold under arcuate track segments  202  with the free ends of legs  205  moving towards base  220 . As shown in  FIG. 6 , in such a collapsed condition, arcuate track segments  202  form a nearly horizontal track segment, such that toy vehicles travelling along the racetrack after such collapse and through first toy vehicle path  228  will continue on to any additional plastic track sections that have been connected to second connection tab  224 . So that partial loop section  200  may achieve such nearly horizontal track segment configuration after its collapse, legs  205  of stand  204  are spaced apart from one another a sufficient distance such that the entire width of arcuate track segments  202  may sit between legs  205 . 
     In order to best support partial loop section  200  in its partial loop configuration, stand  204  is preferably joined to the underside of partial loop section  200  at the hinge joint that is closest to 45 degrees from the plane that includes toy vehicle path  228 . 
     Next, and with reference to  FIG. 7 , a terminal, upper most arcuate track segment  202 ( g ) is configured with a hinge segment for forming a hinged joint with the adjacent, preceding arcuate track segment  202 ( f ) only at the second end of terminal upper most arcuate track segment  202 ( g ), while the first end of such track segment  202 ( g ) is configured for connection to ornamental head member  206 . A head carrier  250  extends forward of the first end of upper most arcuate track segment  202 ( g ) and away from the underside of such track segment  202 ( g ). Thus, when all of arcuate track segments  202  are positioned so as to form partial loop  200 , head carrier  250  extends outward from the top-most portion of partial loop  200  and back toward launch assembly  110 . In this position, head member  206  may be inserted onto head carrier  250 . 
       FIG. 8  is a bottom perspective view of head member  206  mounted on head carrier  250  of terminal arcuate track segment  202 ( g ).  FIG. 8  shows head member  206  in a “set” position, in which head carrier  250  has been inserted into a receiver  252  on the underside of head member  206 . With reference to  FIG. 8  and the rear perspective, bottom, and rear views of detached head member  206  shown in  FIGS. 9, 10, and 11 , respectively, receiver  252  holds a rearwardly spring-biased plate  254 , which plate  254  may be pushed into the body of receiver  252  against the bias of an internal spring (not shown in  FIGS. 8 and 9 ). Thus, when head member  206  is pushed onto head carrier  250 , head carrier  250  pushes plate  254  into receiver  252  until a latch  256  engages an opening  262  in the bottom surface of head carrier  250  (as shown in  FIGS. 16-18 ). Latch  256  is hingedly connected to the underside of receiver  252 , and includes an extension  258  extending outward from a pivot hinge connection  260 . Once spring biased plate  254  is pushed by head carrier  250  into receiver  252  a sufficient distance so that the opening  262  in head carrier  250  engages latch  256 , subsequent movement of latch extension  258  towards head member  206  will pivot latch  256 , causing latch  256  to disengage from head carrier  250 , at which point the internal spring inside of receiver  252  will quickly push plate  254  against head carrier  250  outwards towards a stop position (such stop position being reflected in  FIG. 9 ), in turn causing head member  206  to spring away from partial loop portion  200  of toy racetrack  100 . 
       FIG. 12  is a perspective view of receiver  252  shown removed from head member  206 , and  FIG. 13  is an exploded view of several components of receiver  252 . As shown in  FIGS. 12 and 13 , receiver  252  includes a receiver block housing  270  which is mounted to the underside of head member  206 , such that the underside of head member  206  forms a ceiling for receiver block housing  270  to form a closed assembly. A back end of receiver block housing  270  has an opening  272  sized to receive head carrier  250  and to allow relative sliding movement between head carrier  250  and receiver  252 . As best shown in the top view of receiver block housing  270  shown in  FIG. 14 , latch  256  is pivotally mounted at pivot hinge connection  260  to the bottom side of receiver block housing  270 . A back end of latch  256  includes an upwardly extending hook  274  which moves into and out of the interior of receiver block housing  270  through an opening  276  in the bottom surface of receiver block housing  270  as latch  256  pivots about pivot hinge connection  260 . A spring member  279  biases hook  274  upward into receiver block housing  270 , such that when head carrier  250  is inserted into receiver  252 , hook  274  remains biased toward a position that holds receiver  252  on head carrier  250  until latch  256  is pivoted. 
     With continued reference to  FIGS. 12 and 13 , spring biased plate  254  is positioned within receiver block housing  270  and is mounted for sliding movement within receiver block housing  270 . A spring member  278 , such as a coil spring, biases plate  254  toward the back end of receiver  252 , with the back wall of receiver  252  forming a stop against further movement of plate  254 . Spring member  278  may be attached to a first spring receiving hub  280  on a front wall of receiver block housing  270 , and to a second spring receiving hub  282  on a front wall of spring biased plate  254 . Spring biased plate  254  may also have a guide groove  284  on a top side of plate  254 , which guide groove  284  may engage a guide fin  286  on the underside of head member  206  ( FIG. 15 ) to maintain alignment of plate  254  as it is pushed by head carrier  250  towards the front end of receiver block housing  270 . The underside of head member  206  may have additional guide surfaces  288  on either side of guide fin  286  that engage the top surface of spring biased plate  254  as it moves within receiver block housing  270 . 
     Receiver  252  may be joined to the underside of head member  206  through use of standard threaded members, such as screws or bolts, through flanges  290  on either side of receiver  252  that align with connection hubs  292  on the underside of head member  206 . 
       FIGS. 16, 17, and 18  show top, perspective, and front views, respectively, of head carrier  250  on terminal track segment  202 ( g ). Head carrier  250  has an opening  262  in its base, which opening  262  aligns with opening  276  in the bottom of receiver block housing  270  when head carrier  250  is fully inserted into receiver  252 . In this position, hook  274  on latch  256  engages head carrier  250 , holding it in position until latch  256  is pivoted, after which plate  254  pushes against the front of head carrier  250  so as to cause head member  206  to spring away from head carrier  250 . 
       FIGS. 19 and 20  show head carrier  250  engaging receiver  252  as head member  206  is moved into its set position (head member  206  being shown in phantom). As shown in the perspective view of  FIG. 19 , before head carrier  250  is inserted into receiver  252 , spring biased plate  254  is biased by spring member  278  toward the back end of receiver  252 , such that the forward end of head receiver  250  will come into contact with spring biased plate  254  as head receiver  250  begins to enter receiver  252 . Likewise, and as shown in the perspective view of  FIG. 20 , once head carrier  250  is fully inserted into receiver  252 , spring biased plate  254  is pushed toward the front end of receiver  252 , compressing spring member  278 . Head carrier  250  is in turn held in this set position by upwardly extending hook  274 , which extends upward through opening  262  in head carrier  250 , until such time as latch  256  is pivoted to remove hook  274  from the path of head carrier  250 , thus allowing spring member  278  to rapidly expand and launch head member  206  from terminal track segment  202 ( g ). 
     Moreover, as the center of gravity of partial loop section  200  shifts as a toy vehicle arrives at head member  206 , the partial loop section  200  collapses as the head member  206  springs away from the assembly, and drops to the position shown in  FIG. 6 . 
     Having now fully set forth the preferred embodiments and certain modifications of the concept underlying the present invention, various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will obviously occur to those skilled in the art upon becoming familiar with said underlying concept. It should be understood, therefore, that the invention may be practiced otherwise than as specifically set forth herein.

Technology Category: 1