Abstract:
A locking bicycle pedal includes a ratcheting coiled cable with a male locking plug that mates with a female locking port. A lock, such as a resettable combination lock, secures and releases a catch that secures and releases the plug in the port. When locked in the port, the plug depresses a plunger which constrains a pawl that engages teeth of a toothed wheel of the spool. An optional tracker wirelessly emits GPS location data if a theft is detected.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to bicycles, and, more particularly, to a bicycle pedal having a retractable coiled cable with a mating lock and optional alarm and tracker. 
     BACKGROUND 
     Bicycles have become increasingly popular as a healthier and environmentally friendlier mode of transport. While cycles are most popular within campus towns, many major cities are continually improving cycling infrastructure to encourage cycling. 
     Unfortunately, fear of bicycle theft discourages bicycle use. Many bicycle theft victims do not bother to buy a replacement. Those that do purchase a replacement, tend to substantially taper use. Combating bicycle theft, therefore, is a necessary step toward increasing the use of this sustainable form of transport 
     A consistent finding is that most stolen bicycles, regardless of theft location, are not locked at all, locked improperly or secured using a lock that requires little effort to break or remove. Some bicycles are stolen from places that are assumed to be a safe, when in reality they are not. Others are left unattended and unlocked for short periods of time. For example, sometimes people leave their bike unlocked for just a minute or two while they run into a store, only to find their bicycle gone when they exit. While all locks can be overcome if the opportunity is present and a thief is suitably equipped, inadequate locking practices create a situation conducive for the thief. Observing more-secure locking practices would, at the very least, reduce opportunistic thefts. 
     A reason why many bicycle owners do not bother to lock their bicycles whenever not in use is inconvenience. Carrying a conventional chain or cable and lock can be a hassle. Even if the bicycle has a basket or saddle, the sound of a chain or cable and lock rattling around in a basket or saddle or wrapped around the frame is enough to deter many bicyclists from consistently using such devices. Removing the lock and chain or cable from a basket or saddle or unwrapping it from a frame is tedious. 
     Another problem in preventing theft of a bicycle is that the wheels are easily detachable from the frame, and that unless both wheels and frame are secured, wheels can easily be carried away after being detached. The most secure locking method therefore is to lock the wheels and frame to each other and to an immovable object. 
     However, U-locks, which are en vogue, are not sized to lock both wheels and the frame to an immovable object. A U-lock is a rigid metal ring in the shape of the letter U. The U part of the lock attaches to a crossbar section, and for this reason they are also called D-locks. To lock the bicycle, one locks it physically to some other object, such as a bike rack securely in the ground, parking meter or a flagpole. At best, a typical U-lock will lock a rear wheel and frame to an immovable object. The rear wheel is more costly than the front wheel and more difficult to remove. Thus, one wheel, such as the front wheel, is typically left vulnerable to theft when a U lock is used. 
     To avoid theft of an unlocked front wheel, some bicycle owners will remove it and take it with them. Obviously, that is a hassle and impractical if there is no place to store the wheel. 
     What is needed is a convenient lock that is integrated with a bicycle and can secure a frame and at least one wheel, preferably both wheels. The lock should be useful and in conjunction with other locks. When the bicycle is being used for transportation, the lock should be inconspicuously stored without rattling and without scratching the frame. 
     The invention is directed to overcoming one or more of the problems and solving one or more of the needs as set forth above. 
     SUMMARY OF THE INVENTION 
     To solve one or more of the problems set forth above, in an exemplary implementation of the invention, a an exemplary bicycle pedal according to principles of the invention includes a pedal body providing a surface against which a user&#39;s foot may exert a force. A threaded spindle is rotatably coupled to the pedal body and configured for threaded engagement of a crank arm of a bicycle. Within the pedal body are a spool and axle. The spool and axle are concentric and the spool is rotatable about the axle. The axle is generally perpendicular to the surface of the pedal body against which a user&#39;s foot may exert a force. A security cable is wound on the spool. The security cable has a first free end with a male locking plug. A female locking port is provided in the pedal body. The port is sized to receive the male locking plug. A catch is provided in the female locking port. The catch is movable from a locked position to an unlocked position. In the locked position, the catch engages the plug when the plug is inserted in the port. A lock operably coupled to the catch is user configurable (i.e., may be locked or unlocked by a user) to a locked state and to an unlocked state. The lock prevents movement of the catch from the locked position to the unlocked position when the lock is in the locked state. 
     The lock may comprise a combination lock, such as, by way of example and not limitation, a combination lock having three rotating discs, wherein each rotating disc includes a central aperture and notch, and a toothed locking pin having three teeth. The rotating discs are rotatable about the toothed locking pin when the teeth of the locking pin are not within the notches of the discs. The pedal body may include a window. The combination lock may be within the pedal body, accessible through the window. 
     The spool may be part of a ratchet mechanism. In such an embodiment, the spool includes a toothed disc having a plurality of peripheral teeth. A pivoting pawl controllably engages peripheral teeth of the toothed disc as the spool rotates about the axle. The pawl is constrained from pivoting when the male plug is inserted in the female locking port. When the pawl is constrained, the pawl prevents rotation of the spool in a direction that would permit withdrawal of the security cable wound on the spool. 
     To constrain the pawl, a spring biased plunger is provided. The plunger has a first end in the female locking port, and a second end, opposite the first end, between the locking port and the pawl. The plunger is depressed by the male plug when the male plug is inserted in the female locking port. The second end is operable to constrain the pawl from pivoting when the plunger is depressed by the male plug when the male plug is inserted in the female locking port. In one implementation, a spring biased yoke moveable from a first position to a second position may be provided between the pawl and the second end of the plunger. The yoke may be linked to the pawl. The second end of the plunger urges the spring biased yoke from the first position to the second position, when the plunger is depressed by the male plug, when the male plug is inserted in the female locking port. The yoke constrains the pawl when the yoke is urged into the second position. 
     A pawl release operably coupled to the pawl pivots the pawl away from the teeth of the toothed disc when the pawl release is actuated. The pawl release may comprise a pawl release button actuated by pressing it. 
     A catch release operably coupled to the catch urges the catch into an unlocked position when the catch release is actuated and the lock is in the unlocked state. When urged into the unlocked position, the catch releases (i.e., no longer) engages the plug. This allows the plug to be withdrawn from the port. The catch release may comprise a catch release button actuated by pressing. 
     The locking mechanism may comprise a combination lock, such as a three-disc lock. A toothed locking pin linearly moves from a locking position to an unlocking position. The pin is operably coupled to the catch. When the lock is unlocked, the catch release urges the toothed locking pin into an unlocking position and the catch into an unlocked position when the catch release is actuated. When the lock is locked, the catch release cannot move the toothed locking pin or the catch release. 
     A lock reset is operably coupled to the toothed locking pin. The lock reset urges the toothed locking pin into a position whereby each tooth of the toothed locking pin is positioned in a notch of each disc when the lock reset is actuated. Each disc includes an outer ring that is rotatable relative to the central aperture of each disc. The position of the outer rings relative to the corresponding notches defines a combination for the combination lock. The combination corresponds to an arrangement of the discs in an unlocked state. The lock reset may comprise a button that is operably coupled to the toothed locking pin and actuated by pressing. 
     In one embodiment, a tracker is included in the pedal. The tracker transmits GPS location data when a theft condition is detected. An exemplary tracker includes a GPS receiver, a microcontroller operably coupled to the GPS receiver, a transmitter operably coupled to the microcontroller, an accelerometer operably coupled to the microcontroller, and a power supply operably coupled to the microcontroller. A switch operably coupled to the lock detects if the lock is in a locked state. If the lock is in a locked state and the accelerometer senses accelerations beyond a threshold, a theft condition is determined. In such as case, an alarm (e.g., audible alarm) may be sounded. Additionally, in such as case, the 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other aspects, objects, features and advantages of the invention will become better understood with reference to the following description, appended claims, and accompanying drawings, where: 
         FIG. 1  is a top perspective view of an exemplary bicycle pedal having a retractable coiled cable with a mating lock according to principles of the invention; and 
         FIG. 2  is a first side view of an exemplary bicycle pedal having a retractable coiled cable with a mating lock according to principles of the invention; and 
         FIG. 3  is a medial side view of an exemplary bicycle pedal having a retractable coiled cable with a mating lock according to principles of the invention; and 
         FIG. 4  is a second side view of an exemplary bicycle pedal having a retractable coiled cable with a mating lock according to principles of the invention; and 
         FIG. 5  is a plan view of an exemplary bicycle pedal having a retractable coiled cable with a mating lock according to principles of the invention; and 
         FIG. 6  is a lateral side view of an exemplary bicycle pedal having a retractable coiled cable with a mating lock according to principles of the invention; and 
         FIG. 7  is a bottom view of an exemplary bicycle pedal having a retractable coiled cable with a mating lock according to principles of the invention; and 
         FIG. 8  is a top perspective view of a partially disassembled exemplary bicycle pedal having a retractable coiled cable with a mating lock according to principles of the invention; and 
         FIG. 9  is a plan view of an uncovered portion of an exemplary bicycle pedal having a retractable coiled cable with a mating lock according to principles of the invention; and 
         FIG. 10  is a perspective view of uncovered mechanical components of an exemplary bicycle pedal having a retractable coiled cable with a mating lock according to principles of the invention; and 
         FIG. 11  is a plan view of uncovered mechanical components of an exemplary bicycle pedal having a retractable coiled cable with a mating lock according to principles of the invention; and 
         FIG. 12  is a perspective view of uncovered mechanical components of a mechanical locking mechanism for an exemplary bicycle pedal having a retractable coiled cable with a mating lock according to principles of the invention; and 
         FIG. 13  is a top perspective view of an exemplary bicycle pedal having a retractable coiled cable with a mating lock, and the cable in a partially extended state, according to principles of the invention; and 
         FIG. 14  is a top perspective view of an exemplary bicycle pedal having a retractable coiled cable with a mating lock, and the cable in a locked state, according to principles of the invention; and 
         FIG. 15  is a plan view of an exemplary bicycle pedal having a retractable coiled cable with a mating lock, and an electronics module, according to principles of the invention; and 
         FIG. 16  is a plan view of an exemplary bicycle pedal having a retractable coiled cable with a mating lock, and an exposed electronics module, according to principles of the invention; and 
         FIG. 17  is a high level schematic for an electronics module, according to principles of the invention; and 
         FIG. 18  is a high level block schematic conceptually illustrating an electrical power generator for a bicycle pedal according to principles of the invention. 
     
    
    
     Those skilled in the art will appreciate that the figures are not intended to be drawn to any particular scale; nor are the figures intended to illustrate every embodiment of the invention. The invention is not limited to the exemplary embodiments depicted in the figures or the specific components, configurations, shapes, relative sizes, ornamental aspects or proportions as shown in the figures. 
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 through 7 , a bicycle pedal  100  with an integrated cable lock according to principles of the invention is shown. The pedal  100  comprises foot-operated platform for reciprocating motion propulsion of a bicycle. The pedal  100  provides a spindle  145  connection between the cyclist&#39;s foot and a crank, allowing a cyclist to turn a sprocket and propel the bicycle&#39;s wheels. The pedal  100  is free to rotate, on bearings, relative to the spindle  145 . The spindle  145  connects to the end of a conventional bicycle crank. In the U.S., adult or multi-piece cranks typically have a 9/16-inch (14.2875 mm) hole with 20 threads per inch (TPI). One-piece or children&#39;s cranks in the U.S. use a ½-inch (12.7 mm) by 20 TPI hole. A right-side (usually the drive-side, i.e., the side with the sprocket) pedal spindle is right-hand threaded, and the left-side (usually the non-drive-side) pedal spindle is left-hand (reverse) threaded to help prevent it from becoming loose by precession. Thus, a pedal  100  according to principles of the invention may include a spindle adapted for use with any bicycles having industry standard cranks. One or more pedals of a bicycle may be replaced with a pedal  100  according to principles of the invention. Additionally, bicycles equipped with one or more of the pedals  100  as original equipment, may be supplied from a manufacturer. 
     A body comprised of bottom  105 , intermediate  110  and top  115  is a generally somewhat rectangular shaped, and defines an internal compartment which contains components of the pedal  100 . The pedal include a button  125  for releasing cable, a button  130  for releasing a lock and another button  135  for setting the lock. The exemplary lock is a rotating disc combination lock  120 . A male locking plug  140  attached to a cable  141  plugs into a female port  151  behind sliding access panel  150 . The sliding access panel prevents debris from entering the port  151 , when the plug  140  is not inserted in the port  151 . The pedal  100  may include any aesthetic features and foot gripping features, include textured surfaces to enhance traction. 
     The cable  141  is narrow width to provide flexibility during coiling, and sufficiently long to extend through components of the bicycle frame and wheels. While the invention is not limited to a particular cable length or width, a cable length of at least 2 feet, and preferably at least 3 feet is preferred. Likewise, a width of ¼-inch or less is preferred. In an embodiment where both pedals of a bicycle comprise pedals according to principles of the invention, the cable of each pedal may plug into the locking port of the other pedal. 
     In  FIG. 8 , the top  115  is removed. The recessed opening  122  in the top  115 , prevents a user&#39;s foot from contacting the discs of the lock  120  when pedaling. A plurality of mechanical fasteners, such as threaded screws  117  secure the top  115  to mating threaded holes in the intermediate  110  and/or bottom  105  portions of the pedal  100 . A ratcheting spool  165  contains a wound cable  141 . The cable is fixedly attached at one end to the spool  165  and, at the other end, to the plug  130 . A pawl  160  allows retraction but resists withdrawal of the cable  141  unless the pawl is pivoted away from the teeth of the spool  165 . Such pivoting may be accomplished by pressing button  125 , which is mechanically linked to the pawl in a manner that causes the pawl to pivot about pivot pin  124  ( FIG. 11 ), by linear translation of coupling pin  123 . When the plug  130  is inserted into the locking port  151 , the tip  134  of the plug  130  presses against a plunger  128  biased by spring  127 , which urges the plunger against yoke  226 , which is biased by a spring  129 . In this manner, the plunger  128  prevents movement of the yoke  226 , which prevents depressing the button  125 . Thus, in this manner, the pawl  124  remains locked when the plug  130  is inserted into the port  151 . When the pawl  124  is locked, rotation of the spool  165  to allow withdrawal of cable  141  is prevented. This prevents a thief from extending the cable  141  to facilitate severing the cable  141 . 
     As illustrated in  FIG. 10 , the spool includes a top toothed disc  166  resembling a cog, a bottom disc  167 , and a central cylindrical cord shaft  169  rotating about a concentric axle  168 . The spool  165  may be manually rewound by feeding cable into the pedal assembly or may include a spring to facilitate rewinding. In an exemplary embodiment, a torsion spring  170  coupled to the spool allows sufficient rotations of the spool to unwind the entire cable length and facilitates rewinding by rotationally biasing the spool  165 . The axis of rotation defined by the central axle  168  is generally perpendicular to the top  115  and bottom  105  surfaces of the pedal and orthogonal to the axis of the spindle  145 . 
     In  FIGS. 8 through 11 , details of the male plug  130  are visible. The plug  130  includes a shaft  132 , a neck  133  extending from the shaft  132 , and a bulbous head  134 . The neck  133  has a width (e.g., diameter) that is less than the diameter of the shaft  132 . The bulbous head  134  defines the terminus of the plug  130 . The head  134  may have a conical, frustoconical, ellipsoid or other wedge shape, with a pointed, rounded or flattened tip. The maximum width of the head  134  is about the same as the width (diameter) of the shaft  132 . The shape of the head  134  is conducive for deflecting the catch  153  during insertion. 
     With reference to  FIG. 12 , during locking, the plug  130  is inserted in the cavity  152  of the port  151 . A catch  153 , such as a crescent shaped tab, bolt or other moveable retainer within the port  151  cavity  152 , moves to a position that is flush against the neck  133 , during locking. The larger diameter head  134  cannot pass the catch  153 , during locking. Thus, the plug  130  is retained in the port  151  by the catch  153 , during locking. 
     The catch  153  may be deflectable in one direction, i.e., toward the periphery of the port  151 . Thus, the plug  130  may be inserted in the port  151 , even when the catch  153  is in a locked position. During insertion, the wedge-shaped or conical-shaped head  134  of the plug  130  deflects the catch  153  toward the periphery enough for the head  134  to clear the catch. After the head  134  clears the catch  153 , the catch  153  springs back to the undeflected position against the neck  133 . 
     When unlocked, the catch  153  moves away from the neck  133  by a sufficient distance to clear the head  134 . When unlocked, the plug  130  may be withdrawn from the cavity  152  of the port  151  without appreciable interference between the head  134  and the catch  153 . 
     The locking mechanism  120  comprises a rotating disc lock. Each of a plurality of discs  123  has an outer band  124  and a center disc  228  with a central keyhole aperture  124  including a circular portion and a notch. The outer band  124  is rotatable relative to the center disc  228  to set the combination. The lock  120  is secured by a pin  121  with several teeth  122  on it which mate with the keyhole aperture  126  of each disc  123  when rotated to the unlocked combination. The pin  121  and teeth may move side to side when the lock  120  is in an unlocked state. To change the combination, the lock is positioned to the unlocked combination, achieving an unlocked state. Then the setting button  135  is pressed, which urges the wedge  136  against step  138 , urging the pin  121  and teeth  122  within the corresponding keyhole aperture  126 . Then the outer band  124  may be rotated relative to the center disc  228  which remains fixed in position by the mated teeth  122 . Such rotation resets the combination. 
     When the notched keyhole opening  126  in the discs  128  align with the teeth  122  on the pin  121 , the lock can be opened, by pressing the catch release button  140 . The catch release button  140  is coupled to the catch  153 , which is coupled to the pin  121 . Pressing the button urges the catch  153  and pin  121  and teeth  122  towards the bushing  139 . This motion is only possible when the keyhole opening  126  in the discs  128  align with the teeth  122  on the pin  121 . Otherwise, the teeth  122  collide with the disc  128 , thereby preventing releasing movement of the catch  153 . When the catch  153  is released, the lock  120  is in the unlocked state and the plug  130  may be removed from the cavity  152  of the port  151 . 
     As described above, the locked and unlocked states affect several components. In the locked state, the pawl  160  remains locked, which prevents further withdrawal of the cable  141 , as illustrated in  FIG. 14 . In the locked state, the catch  153  remains locked, which prevents withdrawal of the plug  130  from the cavity  152  of the port  151 . In the locked state, the teeth  122  are not mated with the keyhole opening  126  in the discs  128 , which prevent resetting the combination because the band  124  and disc  126  will rotate together. In the locked state, the cable  141  may wrap around one or more structures of the bicycle (e.g., front and rear wheels) and a security structure such as an abutting bicycle rack or utility pole. 
     In the unlocked state, the ratchet release button  125  actuates the pawl  160 . When pressed, the button  125  releases the pawl  160  by causing it to pivot. When the pawl  160  is released, cable  141  may be withdrawn (i.e., extended) from the spool  165 , as illustrated in  FIG. 13 . In the unlocked state, the combination set button  135  may be depressed to allow the combination lock  120  to be set. In the unlocked state, the catch release button  140  may be depressed, moving the catch  153  to a released position, which allows withdrawal of the plug  130  from the cavity  152  of the port  151 . 
     With reference to  FIGS. 15 through 17 , optionally the pedal  100  may include a tracker  215  and battery  205  contained in a compartment  210  out of the way of the rotating spool  165 . The compartment  210  may be accessible via a removable access panel  200 , to facilitate replacing the battery  205 . The battery  205 , may be rechargeable or disposable. The tracker  215  may be concealed when the access panel  200  is removed, but is shown in  FIG. 16  to facilitate understanding. The tracker  215  contains an acceleration sensor  320  which wakes up the microcontroller  300  when the tracker  215  is moved. In a sleep state, the tracker  215  minimizes power consumption, awaiting only a theft indication and an acceleration signal. 
     A theft indication occurs when the cable has been compromised (e.g., severed). A theft indication may be determined in one of several ways. For example, an acceleration detected while the plug  130  is locked in the port  151  suggests that the cable has been compromised, and may constitute a theft indication. In such a case, the status of the plug  130  is monitored and acceleration signals are monitored to determine a theft indication. The status of the plug may be monitored using one or more switches  350 , such as electromechanical, magneto-mechanical or optical switches. 
     Illustratively, movement of the plunger  128  upon insertion of the plug  130  in the port  151  may trigger an operably coupled switch  139 . The tracker  215  may monitor the state of the switch  139 . When the switch  139  is in a state indicating that the plug is inserted, the tracker  215  monitors acceleration signals. When the switch  139  is in a state indicating that the lock  120  has been unlocked and the plug  130  removed from the port  151 , then the tracker may remain in a sleep state or powered down state to conserve battery power. As another example, the plug  130  may be conductive and complete the conductive path from the plunger  128  to the catch  153 . If a threshold acceleration is detected while the plug  130  is inserted in the port  151 , thereby completing the conductive path from the plunger  128  to the catch  153 , the alarm is sounded. This would indicate that the cable has been compromised and a theft is occurring. In yet another embodiment, a magnetic security sensor may be provided in or adjacent to the port  151 , and the plug  130  may be magnetic or have a magnetic component. When inserted in the port  151 , the plug  130  is detected by the magnetic sensor. If a threshold acceleration is detected when the plug  130  is detected by the magnetic sensor, the alarm is sounded. Again, this would indicate that the cable has been compromised and a theft is occurring. 
     When awakened, due to a theft indication, the tracker  215  periodically detects location using a GPS receiver  305  and antenna  330  operably coupled to the microcontroller  300 . A wireless transceiver  310  (e.g., GSM transceiver) transmits a data via antenna  335  to a remote computing device, i.e., a monitoring station. The remote computing device may be a server, personal computer, phone, pda or other device capable of receiving and processing data transmitted via a GSM or other cellular communications network and/or the Internet. 
     Optionally, an audible alarm may be emitted through a loudspeaker  340  in response to a theft indication, e.g., if the tracker is moved (i.e., accelerated beyond a threshhold acceleration) when the plug  130  is contained in the cavity  152  of the port  151 . 
     To avoid false alarms, a threshold acceleration may be established for a theft indication. The threshold acceleration may comprise accelerations of a certain magnitude for a certain a duration. In this manner, the tracker  215  may avoid alarms and battery consumption when the locked pedal is merely jostled. 
     The power supply components  325  of the tracker may comprise one or more batteries, such as battery  205 , which may be rechargeable or disposable. In the case of a rechargeable battery  205 , one or more charging sources (e.g., photovoltaic cells or generators) may be operably coupled to the battery  205 . 
     By way of example and not limitation, one charging source may comprise a generator such as a pendulum generator. With reference to  FIG. 18 , an exemplary pendulum generator  400  is comprised of a pendulous magnet  405  pivotally attached the pedal  100  (or to a structure such as a housing attached to the pedal  100 ) in a manner that permits pendulous motion of the magnet  405  relative to the pedal  100  and relative to the coil  410 . Pendulous motion is induced by motion of the pedal  100 . An inductive coil  410  is positioned in proximity to the magnet  405 . The pendulum generator  400  thus uses electromagnetic induction to convert mechanical pendulous motion of the magnet  405  relative to the coil  410  into alternating current (AC). As a result of the pendulous motion and attendant changes in direction of motion, the resulting current is an alternating current. Accelerations, decelerations, bumps and turns of an equipped bicycle pedal will all initiate pendulous motion for electric generation. Through the use of a rectifier  415 , the induced alternating current, which periodically reverses direction, is converted to direct current (DC). Optionally, the output of the rectifier may be smoothed by an electronic filter, such as smoothing capacitor  420  coupled to a ground  425 , to produce a steady current. The invention is not limited to a particular rectifier or filter. A battery charging circuit  430  uses the conditioned DC current to charge a rechargeable battery  205 . The recharging circuit may be any type of charging circuit suitable for charging the battery and preventing overcharging of the battery. A nonlimiting example is a window comparator, which allows charging when the battery voltage drops beyond a preset value, and prevents charging when an upper preset voltage is attained. The battery charging circuit  430  may operate independently of the microcontroller  300 , so that the battery  205  may be maintained in a charged state even while the microcontroller  300  is powered down or in a sleep state. 
     While an exemplary embodiment of the invention has been described, it should be apparent that modifications and variations thereto are possible, all of which fall within the true spirit and scope of the invention. With respect to the above description then, it is to be realized that the optimum relationships for the components and steps of the invention, including variations in order, form, content, function and manner of operation, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. The above description and drawings are illustrative of modifications that can be made without departing from the present invention, the scope of which is to be limited only by the following claims. Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, 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, and accordingly, all suitable modifications and equivalents are intended to fall within the scope of the invention as claimed.