Abstract:
An extendable device engages and operates a handle mounted on an electrical switching apparatus. The extendable device includes a first linear portion and a second linear portion, each of the first and second linear portions having a first end and a second end, a handle adaptor extending away from the second end of one of the first and second linear portions and a retainer mechanism structured to engage the first linear portion and the second linear portion such that the extendable device can be adjusted to a particular length and maintained at the particular length. The handle adaptor is structured to engage the handle such that the handle can be moved from a first position to a different second position.

Description:
BACKGROUND 
     1. Field 
     The disclosed concept pertains generally to handle operators and, more particularly, to handle operators which extend beyond a flash protection boundary of, for example, a motor control center. 
     2. Background 
     A flash protection boundary (“FPB”) is implemented and regulated to protect those that work around live electrical equipment from severe injury resulting from an arc flash. An arc flash is a type of electrical explosion that can result from a low impedance electrical connection to ground or a voltage phase in an electrical system. For example, when insulation or isolation between electrified conductors is breached or can no longer withstand the applied voltage, an arc flash can occur. An arc flash can cause substantial damage, fire or injury. An enormous amount of concentrated energy can explode outward from the electrical equipment, spreading hot gases, melting metal, causing death or severe burns and creating intense pressure that can damage hearing or brain function and light that can damage eyesight. The fast-moving pressure wave also can send loose material, such as pieces of equipment, metal tools and other objects, flying, injuring anyone standing nearby. 
     An FPB is calculated to determine the distance surrounding the potential arc point inside which qualified workers must be protected when working. In accordance with the National Fire Protection Association (“NFPA”) 70E standard, FPB is defined as the distance from exposed live parts within which a person could receive a second-degree burn if an electrical arc flash were to occur. This standard also defines incident energy as the amount of energy impressed on a surface, a certain distance from the source, generated during an electrical arc event. Incident energy is expressed in calories per cubic centimeter squared (cal/cm 2 ). As workers get closer to the energized equipment, the energy increases. The FPB is different for different types of equipment and depends, in part, on the voltages involved. Typically, the higher the voltages, the larger the danger zone. At voltage levels above 600 volts, the FPB is the distance at which the incident energy is 1.2 cal/cm 2 , equating to a second-degree burn. For situations where the fault clearing time is 0.1 second (or faster), the FPB is the distance at which the incident energy level equals 1.5 cal/cm 2 . This is defined by NFPA 70E 130.3(a), second paragraph, and is the burn level at which the skin will just heal without scaring. 
     In accordance with NFPA regulations, employers are required to perform a hazard analysis to determine FPBs, to provide appropriate protection for employees and to mark with a warning label electrical equipment having a potential for arc flash. A method of determining this boundary is to calculate the magnitude of the arc (a function of the available short circuit current), estimate how long the arc will last (a function of the interrupting time of the fuse or circuit breaker) and then calculate how far away an individual must be to avoid receiving an incident energy of 1.2 cal/cm 2 . 
     The FPB distance can be calculated according to EQ. 1 as follows (in accordance with formulae D.3(d) and D.3(e) Modified of NFPA 70E-2004).
 
FPB=53×MVA bf ×T  (EQ. 1)
 
wherein:
 
     FPB represents the flash protection boundary in feet; 
     MVA bf  equals 1.732×V×I sc ×0.707/10 6 ; 
     MVA bf  represents the bolted fault energy of the arc (MVA); 
     T represents arcing time (in seconds); 
     I sc  represents bolted short circuit current (in amperes); and 
     V represents line-to-line voltage (in volts). 
     All persons crossing the FPB must wear appropriate personnel protective equipment (PPE), such as, but not limited to, protective clothing, for their protection. 
     In addition to the FPB, there is also a shock protection boundary (“SPB”) which includes a limited approach (“LA”) distance, a restricted approach (“RA”) distance and a prohibited approach (“PA”) distance. The LA distance is the distance an unqualified worker must stay away from energized equipment. The RA distance is the distance that a qualified worker must stay away from energized equipment without voltage rated PPE. The PA distance is the distance considered to be the same as actually touching energized equipment. 
     An FPB is required around electrical equipment, such as switchboards, panelboards, industrial control panels, motor control centers, and similar equipment, when an individual works on or in the proximity of exposed energized (energized and not enclosed, shielded, covered, or otherwise protected from contact) components. This includes conducting activities, such as examination, adjustment, servicing, maintenance or troubleshooting. 
     In the case of motor control centers, a motor control center (“MCC”) generally has an assembly of one or more enclosed sections having a common power bus. An MCC can include several motor starters. An MCC is typically used for low-voltage, three-phase, alternating current motors from about 230 volts to about 600 volts. An FPB is calculated for the MCC, and therefore, a worker must typically enter the FPB to perform operations and maintenance on the MCC unit. 
     The implementation and regulation of FPBs and the provision of PPE afford protection for workers that are required to work in hazardous areas. However, there is room for improvement in removing workers from a hazardous zone. For example, the use of long-handled tools can allow the worker to perform certain operations from outside of the FPB. 
     SUMMARY 
     These needs and others are met by embodiments of the disclosed concept, which provide a device having at least one handle adaptor for engaging and operating a handle mounted on an electrical switching apparatus. 
     In an aspect of the disclosed concept, an extendable device for engaging and operating a handle mounted on an electrical switching apparatus is provided. The extendable device includes a first linear portion having a first end and a second end, the first linear portion extending therebetween, and a second linear portion having a first end and a second end, the second linear portion extending therebetween, the second linear portion having an inside surface that forms a chamber and having an inside distance greater than an outside distance of the first linear portion such that the first linear portion is structured to linearly move toward and away from the chamber of the second linear portion; a handle adaptor extending away from the second end of one of the first and second linear portions; and a retainer mechanism structured to engage the first linear portion and the second linear portion such that the extendable device can be adjusted to a particular length and maintained at the particular length, wherein the handle adaptor is structured to engage the handle such that the handle can be moved from a first position to a different second position. 
     In another aspect of the disclosed concept, a device for engaging and operating a handle mounted on an electrical switching apparatus is provided. The device includes a linear portion having a first end and a second end, the linear portion extending therebetween; a first handle adaptor extending away from the first end of the linear portion; and a second handle adaptor extending away from the second end of the linear portion, wherein each of the first handle adaptor and the second handle adaptor is structured to engage the handle such that the handle can be moved from a first position to a different second position. 
     In still another aspect of the disclosed concept, an extendable device for engaging and operating a handle mounted on an electrical switching apparatus is provided. The extendable device includes a first linear portion having a first end and a second end, the first linear portion extending therebetween, and a second linear portion having a first end and a second end, the second linear portion extending therebetween, the second linear portion having an inside surface that forms a chamber and having an inside distance greater than an outside distance of the first linear portion such that the first linear portion is structured to linearly move toward and away from the chamber of the second linear portion; a first handle adaptor extending away from the second end of the first linear portion; a second handle adaptor extending away from the second end of the second linear portion; a spring mechanism disposed between the first and second linear portions, the spring mechanism structured to exert a force to linearly move the first linear portion away from the chamber of the second linear portion; and a retainer mechanism structured to engage the first linear portion and the second linear portion such that the extendable device can be adjusted to a particular length and maintained at the particular length, wherein at least one of the first handle adaptor and the second handle adaptor is structured to engage the handle such that the handle can be moved from a first position to a different second position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A full understanding of the disclosed concept can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which: 
         FIG. 1  is an isometric view of an extendable handle operator in accordance with an embodiment of the disclosed concept. 
         FIG. 2   a  is an isometric view of an extendable handle operator wherein the handle operator is fully extended in accordance with an embodiment of the disclosed concept. 
         FIG. 2   b  is an isometric view of the extendable handle operator of  FIG. 2   a , wherein the handle operator is fully contracted. 
         FIG. 3  is an isometric view of an extendable handle operator, wherein the handle adaptor is connected to the handle operator by a connector mechanism in accordance with another embodiment of the disclosed concept. 
         FIG. 4  is an isometric view of an extendable handle operator, wherein the handle adaptor includes an aperture formed therein in accordance with another embodiment of the disclosed concept. 
         FIG. 5  is an isometric view of a non-extendable handle operator having two handle adaptors in accordance with another embodiment of the disclosed concept. 
         FIG. 5   a  is an isometric view of a handle operator having a fixed extension portion and two handle adaptors in accordance with another embodiment of the disclosed concept. 
         FIG. 6  is an isometric view of an extendable handle operator having two handle adaptors in accordance with another embodiment of the disclosed concept. 
         FIG. 6   a  is an isometric view of an extendable handle operator having a gripping handle and one handle adaptor in accordance with another embodiment of the disclosed concept. 
         FIGS. 7   a  and  7   b  are isometric views of a handle operator, wherein the handle operator is engaged with a motor control center disconnect handle in different operational positions in accordance with another embodiment of the disclosed concept. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The disclosed concept is described in association with a handle operator for a motor control center, although the disclosed concept is applicable to handle operators for a wide range of electrical equipment and systems. 
     Directional phrases used herein, such as, for example, “left,” “right,” “top,” “bottom,” “upper,” “lower,” “front,” “back,” “forward,” “above,” “below,” “clockwise,” “counterclockwise” and derivatives thereof, relate to the orientation of the elements shown in the drawings and are not limiting to the claims unless expressly recited therein. 
     As employed herein, the statement that two or more parts are “coupled” or “connected” together shall mean that the parts are joined together either directly or joined through one or more intermediate parts. 
     As employed herein, the term “number” shall mean one or an integer greater than one (i.e., a plurality). 
       FIG. 1  shows extendable handle operator  1 . In  FIG. 1 , the handle operator  1  is structured to have a linear shape. The handle operator  1  includes a first linear portion  25  and a second linear portion  30 . The first linear portion  25  extends from a first end  60  to a second end  40 . The second linear portion  30  extends from a first end  70  to a second end  45 . The linear portions  25 ,  30  can have various shapes, such as, for example and without limitation, cylindrical or rectangular. The example second linear portion  30  is tube-like and has a linear wall that forms a chamber  50 . The chamber  50  can be sized such that the first linear portion  25  can be slidably disposed at least partially within the chamber  50 . For example, the second linear portion  30  can have an inside distance that is larger than the outside distance of the first linear portion  25 . In an embodiment, the inside diameter of the second linear portion  30  can be greater than the outside diameter of the first linear portion  25 . The first end  70  of the second linear portion  30  can be structured to receive the first end  60  of the first linear portion  25 . 
     The handle operator  1  has a spring mechanism  35  disposed between the first and second linear portions  25 , 30 , and exerts a force to bias the first linear portion  25  away from the chamber  50  of the second linear portion  30 . The spring mechanism  35  can include various designs known in the art. The example spring mechanism  35  is a coil spring which is disposed within the chamber  50  of the second linear portion  30  and biases the first linear portion  25 . The spring mechanism  35  allows the first linear portion  25  to extend and contract such that the length of the handle operator  1  is extendable and contractable. Further, the handle operator  1  has a retainer mechanism which allows the handle operator  1  to be adjusted to various lengths to maintain the handle operator  1  at a desired length. The example retainer mechanism includes a nub  80  formed on the first linear portion  25  and detents  90  formed on the second linear portion  30 . The nub  80  is biased upward to engage one of detents  90 . It will be appreciated that a wide range of different retainer mechanisms can be employed. For example, the retainer mechanism can include a double nub and detent formation such that two nubs are formed on a first linear portion and are each positioned 180° apart, and two sets of detents are formed on a second linear portion and each set is positioned 180° apart. The second end  40  of the first linear portion  25  is structured to engage a handle adapter  15 . Alternatively, the second end  45  of the second linear portion  30 , can engage the same or similar or different handle adaptor. The example handle adaptor  15  extends away from (e.g., without limitation, perpendicular from) the second end  40  of the first linear portion  25 . The handle operator  1  can be fabricated such that the handle adaptor  15 , the second end  40  and the first linear portion  25  are formed as a single piece or structure. Alternatively, the handle adaptor can be fabricated as a separate piece or structure and connected or otherwise coupled to the second end  40  of the first linear portion  25  by a connector  65  (shown in  FIG. 3 ). The handle adaptor  15  can be connected or otherwise coupled to the second end  40  using various conventional techniques known in the art. The handle adaptor  15  is structured to engage at least a portion of a handle (not shown) on a piece of electrical equipment (not shown), such as, for example and without limitation, a disconnect handle  310  (shown in  FIGS. 7   a  and  7   b ) on a motor control center unit (shown in  FIGS. 7   a  and  7   b ). The size and shape of the handle adaptor  15  can depend on the size and shape of the corresponding handle to be engaged. 
     The lengths of the first and second linear portions  25 , 30  and the spring mechanism  35  can vary and can depend on the flash protection boundary (“FPB”) which surrounds particular electrical equipment or systems (not shown). For example, the lengths of the first and second linear portions  25 ,  30  and the spring mechanism  35  can be such that the total length of the handle operator  1  is extendable beyond the FPB. The example handle operator  1  can be fully extended, fully contracted, or partially extended and contracted. In  FIG. 1 , the handle operator  1  has an example spring-loaded, plunger-like, detent design. 
       FIGS. 2   a  and  2   b  show another handle operator  1   a  having the first linear portion  25 , the second linear portion  30 , the first end  60  and the second end  40  of the first linear portion  25 , the first end  70  and the second end  45  of the second linear portion  30 , the chamber  50 , the nub  80 , the detents  90  and handle adaptor  15 , as shown in  FIG. 1 . The handle operator  1   a  in  FIGS. 2   a  and  2   b  does not include the spring mechanism  35 , as shown in  FIG. 1 .  FIG. 2   a  shows the handle operator  1   a  fully extended, and  FIG. 2   b  shows the handle operator  1   a  fully contracted. In  FIG. 2   a , when handle operator  1   a  is fully extended, only a small length of the first linear portion  25  is disposed within the chamber  50  of the second linear portion  30 . In  FIG. 2   b , when handle operator  1   a  is fully contracted, nearly the entire length of the first linear portion  25  is disposed within the chamber  50  of the second linear portion  30 . 
       FIG. 3  shows another handle operator  1 ′ having the respective first and second linear portions  25 ,  30 , the respective first and second ends  60 ,  40  of the first linear portion  25 , the respective first and second ends  70 ,  45  of the second linear portion  30 , the chamber  50 , the nub  80 , the detents  90 , the spring mechanism  35  and the handle adaptor  15 , as shown in  FIG. 1 .  FIG. 3  further shows a connector  65  which couples the handle adaptor  15  to the second end  40  of the first linear portion  25 . The connector  65  is fabricated as a separate piece or structure from the handle adaptor  15  and the first linear portion  25 . For example, the connector  65  can be structured to receive a variety of handle adaptors having different sizes and/or shapes that can be interchangeable with handle adaptor  15 . 
       FIG. 4  shows another handle operator  1 ″ having the respective first and second linear portions  25 ,  30 , the respective first and second ends  60 ,  40  of the first linear portion  25 , the respective first and second ends  70 ,  45  of the second linear portion  30 , the chamber  50 , the nub  80 , the detents  90 , the spring mechanism  35  and the handle adaptor  15 , as shown in  FIG. 1 .  FIG. 4  further shows an aperture  17  formed in the handle adaptor  15  for use in engaging a handle (not shown). The size and shape of the aperture  17  can vary depending on the size and shape of the corresponding handle to be engaged. In one embodiment, the aperture  17  can be a key-type slot having essentially the same profile as the corresponding handle to be engaged. The handle adaptor  15  can be fitted over at least a portion of the corresponding handle to be engaged such as the disconnect handle  310  (shown in  FIGS. 7   a  and  7   b ). 
       FIG. 5  shows a non-extendable handle operator  100  in accordance with an embodiment of the disclosed concept. The handle operator  100  is structured to have a linear shape. The handle operator  100  includes a linear portion  130 . The linear portion  130  extends from a first end  140  to a second end  145 . The linear portion  130  can have various shapes, such as, for example, cylindrical or rectangular. Further, the length of linear portion  130  can vary and can depend on the FPB that surrounds particular electrical equipment or systems (not shown). For example, the length of linear portion  130  can be such that the length of handle operator  100  is greater than the length of the FPB. The first end  140  and the second end  145  can be structured to engage a respective first handle adapter  115  and a second handle adaptor  120 . The example first and second handle adaptors  115 ,  120  each extend away from (e.g., without limitation, perpendicular) from the first end  140  and second end  145 , respectively, of the linear portion  130 . The first and second handle adaptors  115 ,  120  can be connected or otherwise coupled to the respective first and second ends  140 ,  145  using various conventional techniques known in the art. Each of the first and second handle adaptors  115 ,  120  are structured to engage at least a portion of a handle (not shown) on a piece of electrical equipment (not shown), such as, for example, a disconnect handle  310  (shown in  FIGS. 7   a  and  7   b ) on a motor control center unit (shown in  FIGS. 7   a  and  7   b ). The size and shape of the first and second handle adaptors  115 ,  120  can depend on the size and shape of the corresponding handle to be engaged. In an embodiment, the first handle adaptor  115  can be designed to engage a particular handle style, and the second handle adaptor  120  can be designed to engage a different handle style. 
       FIG. 5   a  shows handle operator  100 ′ in accordance with an embodiment of the disclosed concept. The handle operator  100 ′ has the linear portion  130 , the first end  140 , the second end  145 , the first handle adaptor  115  and the second handle adaptor  120 , as shown in  FIG. 5 .  FIG. 5   a  further shows a fixed extension portion  135  having a first end  136  and a second end  137 . The first end  136  of the fixed extension portion  135  is connected or otherwise coupled to the first end  140  of the linear portion  130 . The second end  137  of the fixed extension portion  135  is connected or otherwise coupled to the handle adaptor  115 . As an alternate embodiment (not shown), the first end  136  of the fixed extension portion  135  can be connected or otherwise coupled to the second end  145  of the linear portion  130  and the second end  137  of the fixed extension portion  135  can be connected or otherwise coupled to the second handle adaptor  120 . 
       FIG. 6  shows a handle operator  200  structured to have a linear shape. The handle operator  200  includes a first linear portion  225  and a second linear portion  230 . The first linear portion  225  extends from a first end  260  to a second end  240 . The second linear portion  230  extends from a first end  270  to a second end  245 . The linear portions  225 , 230  can have various shapes, such as, for example and without limitation, cylindrical or rectangular. The example second linear portion  230  is tube-like and has a linear wall that forms a chamber  250 . The chamber  250  can be sized such that the first linear portion  225  can be slidably disposed at least partially within the chamber  250 . For example, the second linear portion  230  can have an inside distance that is larger than the outside distance of the first linear portion  225 . In an embodiment, the inside diameter of the second linear portion  230  can be greater than the outside diameter of the first linear portion  225 . The first end  270  of the second linear portion  230  can be structured to receive the first end  260  of the first linear portion  225 . 
     The example handle operator  200  has a spring mechanism  235  disposed between the first and second linear portions  225 , 230 , in order to bias the first linear portion  225  away from the chamber  250  of the second linear portion  230 . The spring mechanism  235  can include various designs known in the art. The example spring mechanism  235  is a coil spring which is disposed within the chamber  250  of the second linear portion  230  and biases the first linear portion  225 . The spring mechanism  235  allows the first linear portion  225  to extend and contract such that the length of the handle operator  200  is extendable and contractable. Further, the handle operator  200  has a retainer mechanism which allows the handle operator  200  to adjust to various lengths and to maintain the handle operator  200  at a desired length. The example retainer mechanism includes a nub  280  formed on the first linear portion  225  and detents  290  formed on the second linear portion  230 . The nub  280  is biased upward to engage one of detents  290 . The second end  240  of the first linear portion  225  is structured to engage a first handle adapter  215 . The second end  245  of the second linear portion  230  is structured to engage a second handle adaptor  220 . The example first and second handle adaptors  215 ,  220  extend away from (e.g., without limitation, perpendicular from) the respective second ends  240 ,  245  of the respective first and second linear portions  225 ,  230 . The first and second handle adaptors  215 ,  220  can be connected or otherwise coupled to the respective second ends  240 ,  245  using various conventional techniques known in the art. The first and second handle adaptors  215 ,  220  are structured to engage at least a portion of a handle (not shown) on a piece of electrical equipment (not shown), such as, for example, a disconnect handle  310  (shown in  FIGS. 7   a  and  7   b ) on a motor control center unit (shown in  FIGS. 7   a  and  7   b ). The size and shape of the first and second handle adaptors  215 ,  220  can depend on the size and shape of the corresponding handle to be engaged. In an embodiment, the first handle adaptor  215  can be designed to engage a particular handle style and the second handle adaptor  220  can be designed to engage a different handle style. 
       FIG. 6   a  shows handle operator  200 ′ in accordance with an embodiment of the disclosed concept. The handle operator  200 ′ has the first linear portion  225 , the second linear portion  230 , the first and second ends  260 , 240 , respectively, of the first linear portion  225 , the first and second ends  270 , 245 , respectively, of the second linear portion  230 , the chamber  250 , the spring mechanism  235 , the nub  280 , the detents  290  and the first handle adaptor  215  as shown in  FIG. 6 .  FIG. 6   a  further shows a gripping handle  255 . The gripping handle  255  is T-shaped and has an end  256 . The end  256  of the gripping handle  255  is connected or otherwise coupled to the second end  245  of the second linear portion  230 . The gripping handle  255  provides a mechanism for an operator to hold or grasp, e.g., with two hands, the handle operator  200 ′ to rotate the handle operator  200 ′ and correspondingly rotate a handle such as the disconnect handle  310  (shown in  FIGS. 7   a  and  7   b ). The shape of the gripping handle  255  is not limiting; i.e., a T-shape shown in  FIG. 6   a  is merely illustrative. The gripping handle  255  can be structured in a wide variety of designs and configurations. In an alternate embodiment (not shown), the end  256  of gripping handle  255  can be connected or otherwise coupled to the first end  240  of the first linear portion  225  and the handle adaptor  220  (shown in  FIG. 6 ) can be connected or otherwise coupled to the second end  245  of the second linear portion  230 . 
       FIGS. 7   a  and  7   b  show a handle operator  300  is structured to have a linear shape. The handle operator  300  includes a linear portion  325  which extends from a first end  340  to a second end (not shown). The first end  340  of the linear portion  325  is structured to engage a handle adapter  315 . The example handle adaptor  315  extends away from (e.g., without limitation, perpendicular from) the first end  340  of the linear portion  325 . The handle adaptor  315  can be connected to the first end  340  using various conventional techniques known in the art. The example handle adaptor  315  is connected or otherwise coupled to the first end  340  using a connector  360 . The handle adaptor  315  is structured to engage the upper portion  355  of the disconnect handle  310 , or a somewhat different upper end (not shown) of a different disconnect handle (not shown). The handle  310  is pivotally mounted (pivot not shown) on the motor control center unit  320 . The linear portion  325  is horizontally aligned with the pivot point (not shown) of the corresponding handle  310  to be engaged. The size and shape of the handle adaptor  315  can depend on the size and shape of the upper portion  355  of the handle  310  to be engaged. An operator (not shown) can move the handle operator  300  to correspondingly switch the disconnect handle  310  clockwise from a first position shown in  FIG. 7   a  to a different second position shown in  FIG. 7   b .  FIGS. 7   a  and  7   b  show one handle  310  mounted on a motor control center unit  320 . It will be appreciated that the configuration of the motor control center can include a plurality of units and each unit can include a disconnect handle mounted thereon. 
     It will be appreciated that an operator can be located outside of the FPB (not shown), which is established for the motor control center unit  320  such that the operator holds the handle operator  300  which has a length that is greater than the length of the FPB. 
     The example handle operators  1 ,  1   a ,  1 ′,  1 ″,  100 ,  100 ′,  200 ,  200 ′ and  300  can be constructed of various materials known in the art including durable, rigid materials. Suitable materials for the linear portions  25 ,  30 ,  130 ,  255 ,  230  and  340  can include polyester pull traded forms or extruded thermo-plastic polymers. The materials may be glass filled. Further, the material will include an electrically-insulative material. Then handle adaptors  15 ,  20 ,  115 ,  120 ,  215 ,  220  and  315  can be constructed of metal or plastic. If constructed of an electrically-conductive material, the handle adaptor material will also include an electrically-insulative material. The fixed extension  135  can be constructed of any of these materials which are suitable for the linear portions  25 ,  30 ,  130 ,  255 ,  230  and  340 . The gripping handle can be constructed of a wide variety of materials and can include any of these materials which are suitable for the handle adaptors  15 ,  20 ,  115 ,  120 ,  215 ,  220  and  315 . 
     While specific embodiments of the disclosed concept have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the disclosed concept which is to be given the full breadth of the claims appended and any and all equivalents thereof.