Abstract:
An improved approach is provided for mounting individual wires from multi-wire cables onto circuit boards. A wire comb is mounted adjacent one or more ends of the circuit board to permit a rapid yet positive way to space apart individual wires, to hold them in place; and to permit welding or soldering of the wires to the appropriate connections or the circuit board during an overmolding process.

Description:
FIELD OF THE INVENTION  
       [0001]     The invention relates connecting wires to circuit boards. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0002]     The present invention, its objectives and advantages will become more apparent from the following detailed description when read in conjunction with the accompanying drawings in which:  
         [0003]     FIGS.  1 ( a )- 1 ( b ) are plan views of a circuit board according to embodiments of the present invention;  
         [0004]      FIG. 1 ( c ) is a top plan view of a VGA connector, corresponding cables, and the wire mount of the present invention;  
         [0005]     FIGS.  2 ( a ) - 2 ( b ) are plan views of USB and PS/2 cable assemblies and wire mounts according to embodiments of the present invention;  
         [0006]      FIG. 3  is a side elevational view of a portion of  FIG. 2 ( a ) or  FIG. 2 ( b );  
         [0007]     FIGS.  4 ( a )- 4 ( f ),  5 ( a )- 5 ( f ),  6 ( a )- 6 ( f ) and  7 ( a )- 7 ( d ) are various views of wire combs according to various embodiments of the present invention;  
         [0008]      FIG. 8 ( a ) is the top plan of a circuit board according to embodiments of the present invention, prior to mounting wire combs thereon;  
         [0009]      FIG. 8 ( b ) is a perspective view of a top surface of a circuit board with a wire comb mounted adjacent each end thereof, according to embodiments of the present invention;  
         [0010]      FIG. 8 ( b ) is a perspective view of a bottom surface of a circuit board with a wire comb mounted adjacent each end thereof, according to embodiments of the present invention;  
         [0011]     FIGS.  9 ( a )- 9 ( c ) provide detailed views of aspects of the present invention;  
         [0012]     FIGS.  10 ( a )- 10 ( d ) show various stages and views of an overmolded circuit board according to embodiments of the present invention. 
     
    
     BACKGROUND  
       [0013]     Computer connection cables may include so-called inline circuitry to perform various functions on the signals being transmitted. By “inline circuitry” (or “inline circuits”) we mean any electronic circuitry (possibly on a printed circuit board—PCB) that may be incorporated in a computer cable, regardless of the cable&#39;s or circuitry&#39;s function. For example, U.S. patent application Ser. No. 09/951,774, entitled “Passive video multiplexing method and apparatus,” the contents of which are incorporated herein by reference, describes a so-called Rack Interface Pod (RIP) which is provided for receiving video signals from a server computer and providing them to a remote user via a local area network (LAN), preferably an Ethernet LAN. Similarly, U.S. patent application Ser. No. 11/123,075, titled “Computer interface module,” and filed May 6, 2005, the contents of which are incorporated herein by reference, describes RIPs and related circuitry.  
         [0014]     It is generally desirable that inline circuits (and the corresponding inline PCBs on which they are mounted) be small. This allows for so-called “lump in the cable” designs, where the inline circuit is formed integral with the cable, appearing as a bulge or lump in the cable. An example of such a circuit can be seen, e.g., in FIG. 24 of U.S. patent application Ser. No. 11/123,075, which illustrates a Rack Interface Pod (RIP) device having two network connectors located in the main body and integral therewith. In order to achieve a lump/bulge in cable effect, inline PCBs are preferably formed by molding an appropriate material over them after the wires have been connected to the PCBs.  
         [0015]     The inventors realized that the size of inline PCBs made their manufacture difficult. In particular, the inventors noticed that the size of the PCBs generally meant that the wire connection locations or contacts on the PCBs were close together. This closeness of the contacts increases the risk of wires from one contact touching an adjacent contact. The inventors further realized that this risk was increased by the overmolding process used to create the desired inline effect.  
         [0016]     When connecting a cable containing twisted pairs to a PCB, it is necessary to untwist an end portion of the wires. The inventors also realized that, especially in the case of twisted pairs, it is desirable to keep the length of the untwisted wires to a minimum. This requirement is made more difficult by small (e.g., inline) PCBs.  
         [0017]     Additionally, in the case of inline PCBs, since the wires may, by their very nature, be moved about and possibly pulled, there is increased risk of the wires disconnecting from the PCBs.  
       DESCRIPTION  
       [0018]     Embodiments of the invention will now be described in connection with a number of exemplary cable systems. The examples given use an inline circuit mounted in a known manner on a PCB. Those skilled in the art will realize that the invention is not limited to the exemplary systems or circuits shown. The examples describe the use of CAT 5 (Category 5) cables. As is well known, CAT 5 cables consist of four twisted pairs of copper wire supporting frequencies up to 100 MHz and speeds up to 1000 Mbps. Again it will be clear to those skilled in the art that the invention is not limited to CAT 5 or any other type or category of cable.  
         [0019]     FIGS.  1 ( a )- 1 ( b ) show top and bottom plan views, respectively, of a PCB  100  having electronic circuitry (generally denoted  102 ) mounted thereon in a known manner. As noted, the function of the circuits  102  should not be considered to limit the scope of the invention. However, in some presently preferred embodiments of the invention, the PCB is to be connected inline in a cable system to be used in a KVM system and the circuitry  102  performs appropriate KVM functions such those disclosed in U.S. application Ser. No. 09/951,774, incorporated herein by reference.  
         [0020]     In order to facilitate external electronic connection to the circuitry  102  thereon, the PCB  100  includes a number of electrical contacts  104  (also denoted “J 3 ”),  106  (also denoted “J 2 ”) (on a first surface  108  thereof) and  110  (also denoted “J 1 ”) (on a second surface  112  thereof). For convenience, the first surface  108  is referred to herein as the “top” surface and the second surface  112  is referred to as the “bottom” surface. In the example shown, reference  104  refers collectively to the eight contacts on the left side of the PCB in  FIG. 1 ( a ), reference  106  refers collectively to the eight contacts on the right side of the PCB as shown in  FIG. 1 ( a ), and reference  110  refers collectively to the eight contacts on the bottom surface of the PCB, as shown in FIGS.  1 ( b ).  
         [0021]      FIG. 1 ( c ) shows a plan view of a VGA cable assembly  104 , the top plan view of a PCB  100  and a cable assembly  116  (e.g., a CAT 5 cable). The VGA cable assembly  104  includes a plug  118 , cable  120  and a pig tail  122  that includes individual wires (seven in this example) that have been spread or fanned out.  
         [0022]     The second cable assembly  116 , for example, includes a plug  124  (e.g., a standard RJ-45 connector), cable  126  and a pig tail  128  including, in this case, eight individual wires that have been fanned out. Wire combs  130  and  132  are shown mounted adjacent opposite ends of the circuit board  100 , and each comb  130  and  132  holds a respective group of individual wires, in this example seven (7) and eight (8), respectively.  
         [0023]     Wires in the cable  126 , preferably a CAT 5 cable, electronically connect the circuits  102  on the PCB  100  to the first connector  124 , in this case a standard RJ-45 connector. Wires in the second cable  120 , a shielded  5  cable, electronically connect the circuits  102  via contacts  106  on the PCB  100  to a video connector  118 , in this example a VGA connector.  
         [0024]     As shown in FIGS  1 ( a )- 1 ( c ), on the upper or top surface  108  of the PCB  100 , some or all of the wires from the first cable  126  each connect to different ones of the eight contacts  104  and to the connector  124 . Similarly, some or all of the wires from the second cable  120  connect to the contacts  106 .  
         [0025]     FIGS.  2 ( a )- 2 ( b ) show bottom plan views of the cable assembly shown in FIGS.  1 ( a )- 1 ( c ).  FIG. 2 ( a ) shows a USB cable assembly  128  that includes a USB connector plug  130 , cable  132  and a pig tail  134  of three individual wires that are shown being held by a three-position wire comb  136  that is itself mounted to the bottom surface  112  of circuit board  100 . In this exemplary embodiment, wire comb  136  is positioned directly opposite the location of wire comb  132  in  FIG. 1 ( c ).  
         [0026]      FIG. 2 ( b ) shows an alternative arrangement for the same end of circuit board  100 . In this example, the circuit board  100  is connected to PS/2 keyboard and mouse cable assemblies,  138  and  140 , respectively, which include their respective connector plugs  142  and  144 , their cables  146  and  148 . In each cable  146  and  148 , the individual wires have been fanned out into pig tails  150  and  152 , respectively, and the wires are shown as being held by wire comb  154  on the bottom surface  112  of circuit board PCB.  100 . Here again, wire comb  154  is located directly opposite wire comb  132  on the same end of circuit board  100 . As shown in  FIG. 2 ( b ), on the lower surface  112  of the PCB  100 , some or all of the wires from each of the mouse cable assembly  140  and the keyboard cable assembly  114  connect to contacts  122 .  
         [0027]      FIG. 3  shows a side view of circuit board  100  as described above with reference to the embodiments of  FIG. 2 ( b ), with a shielded video cable  120 , a shielded keyboard cable  146 , and a shielded mouse cable  148  being connected at one end of circuit board  100 , and cable  126  attached to the other end. This view also shows the relative positions of wire combs  130 ,  132  and  154  on circuit board  100 . In addition, as shown in FIGS.  3 ,  8 ( a ) and  8 ( b ) the braided grounding shield  121  included within cable  120  can be connected to a ground connector  131 , while the braided shield  143  included within cables  146  and  148  can be connected to ground connectors  133  and  135 , respectively, to conduct ESD impulses to the chassis ground at the PC. An extended ground shield  137  can also be provided on the circuit board PCB  100  adjacent and around connectors  131 ,  133  and  135 , as shown in  FIG. 8 ( a ).  
         [0028]     Further, the circuit board includes a plurality of spaced apart ESD spark gaps  141  that can vary in size fro about 0.0035 inch to about 0.040 inch, and with one spark gap being available for each contact pad  106  and they are formed directly on the circuit board PCB  100 . Each respective spark gap  141  will have a connection path, as at  139 , extending to the ground shield  137 , and another, as at  151 , extending toward and in contact with one connector pad where ESD discharge protection is required.  
         [0029]     The plurality of the spaced apart spark gaps  141  are positioned between the mounting holes  202 / 204  and  206 / 208  on the circuit board PCB  100  for wire combs  132  and  134 / 154 , for example. Consequently, the mounting of wire combs  132  and  136 / 154  on the circuit board PCB  100  will position the flat base  52  of such wire combs so that it overlies the whole row of spark gaps  141 . In fact, the spark gaps extend along the center line of the wire combs. Consequently, mounting of wire combs  132  and  136 / 154  will cause the base  52  to directly overlie the plurality of spark gaps. As mounted, base  52  of wire combs  132  and  136 / 154  will also fit tightly on the circuit board PCB  100 , and in fact base  52  will preferably be flush with the solder mask surrounding the spark gaps  141 . That relationship not only forms an effective seal between the surface of circuit board PCB  100  and the bottom of the wire combs, but also forms small chambers at the spark gaps  141  between the surface of the circuit board PCB  100  and the bottom or base.  52  of the wire combs  132  and  136 / 154 .  
         [0030]     The use of wire combs  132  and  136 / 154  thereby provides integral protection of these spark gaps  141 , and protects them from the molding and over molding materials by preventing the such molding material from filling the space between the circuit board and the bottom of the wire combs. As noted previously, each spark gap  141  resides in the surface of the circuit board PCB  100  at a point below and underneath wire combs  132  and  136 / 154 . The location of the wire combs  132  and  136 / 154  over spark gaps  141 , and the seal it provides, prevents overflowing material from passing beneath the wire combs and prevents that material from covering or encapsulating the spark gaps which would render the spark gaps ineffective. Were that to occur, the overflowing material, for example PE, would alter, by raising, the break down voltage of the spark gap.  
         [0031]     The over molding can be accomplished in a two step process beginning with a low temperature, low pressure polyurethane material, PE. That molding step would be followed using and outer molded cover preferably formed from a PVC material that will be used under a higher temperature and a higher pressure. By using wire combs in a flush or tight fitting relationship with the circuit board PCB  100 , and a two stage over molding process, the molding material will not flow beneath the wire combs or between the base  52  and the circuit board PCB  100 . This provides protection for and the continued effectiveness of spark gaps  141 .  FIG. 8 ( a ) also shows an additional set of spaced apart spark gaps  211  at the opposite end of the circuit board PCB  100 . These too would be protected by the presence of a wire comb mounted there over.  
         [0032]     In presently preferred embodiments, each wire comb is comprised of a molded resin or plastic, including, for example, a rigid PVC resin, nylon, HDPE, PVC, ABS, PC or other like materials. In presently preferred embodiments of the invention, each wire comb is about 18.5 mm long and about 2.5 mm wide and about 2.5 mm high. Each mounting pin can be hexagonal in cross-section, although other cross-sectional shapes are included, and each pin has a width of about 1.1 mm between the flat sides and a width of about 1.26 mm at the point, and extends about 1.5 mm below the bottom surface of base of the wire comb.  
         [0033]     FIGS.  4 ( a )- 6 ( f ) show a variety of designs or arrangements for the wire combs according to embodiments of the present invention. FIGS.  4 ( a )- 4 ( d ) show a three (3) slot wire comb  136 , FIGS.  5 ( a )- 5 ( f ) show a six (6) slot wire comb  154 , and FIGS.  6 ( a )- 6 ( f ) show an eight (8) slot wire comb  130 . FIGS.  4 ( a )- 4 ( d ) show wire comb  136  as being comprised of a base  52 , a pair of upstanding, spaced apart walls  54  and  56 , and mounting pins  58  depending from opposing ends of the base  52 . Wall  54  includes three wire openings or slots  54   a - e , and wall  56  includes a set of three openings or slots  56   a - c . The two sets of opening  54   a - c  and  56   a - c  are preferably aligned so that an individual wire&#39;s insulating coating will be held by each pair of openings, for example  54   a  and  56   a . However, it should be understood that only one wall, for example  54  could be used with its set of openings. This feature is shown in  FIG. 4 ( f ), where wall  54  is shown in full line and wall  56  is shown in dotted line, as an indicating that it could be removed. Also, the location of the walls  54  and  56 , or only one when that embodiment is used, can be positioned in the center of base  52 , on one side or the other, or at some angle, depending on the location of use, the wire configuration and other similar factors. Further, the present invention encompasses the concept of having the openings formed as part of the base  52  where a low profile wire comb is either preferred or needed.  
         [0034]     As shown in  FIG. 4 ( b ), opening  54   a  could have an upper portion defined by parallel walls  51  and  53 , and a circular or rounded base area  55 .  
         [0035]     It should be understood, however, that the slots or openings  54   a - 54   c  could have other shapes including, for example, extending the parallel wall portions down full length of the opening, or the rounded portion could be modified so as to encompass the and form a top opening into the rounded shape. Further the overall cross sectional shape, of the openings could exhibit a v-shaped slot, a u-shaped slot or some other shape so that the individual wire could be held in a desired position. Suitable shaped openings or grooves could also be formed directly in the base itself. An example of this is shown in  FIG. 4 ( g ), where such wire openings  250  are formed directly in base  52 ′.  
         [0036]     FIGS.  5 ( a )- 5 ( f ) show an exemplary seven-slot wire comb  154 , according to embodiments of the present invention. As can be seen from the drawings, not all the slots are of equal size and not all the slots are equally spaced.  
         [0037]     FIGS.  6 ( a )- 6 ( f ) show an exemplary eight slot wire comb  130  with a base  32 , according to embodiments of the present invention, upstanding walls  34  and  36  and respective openings  34   a - h  and  36   a - h . Mounting pins  38  extend downward from base  32 .  
         [0038]     FIGS.  7 ( a )- 7 ( f ) show an exemplary six-slot wire comb  154 , according to embodiments of the present invention. The comb  154  is comprised of a base  82 , walls  84  and  86 , which respectively contain openings  84   a - 84   f  and  86   a - 86   f , and mounting pins  88 .  
         [0039]      FIG. 6 ( b ) is a bottom view of the wire comb  130  and shows, for example, the mounting pins  38 , with the left pin being offset by a space (denoted “a”) from the leftmost end. In presently preferred embodiments of the present invention, each wire comb  30 ,  50  and  154 , is comprised of a molded resin or plastic, such as a rigid PVC resin. Each wire comb is about 18.5 mm long and about 2.5 mm wide and about 2.5 mm high. Each mounting pin can be hexagonal in cross-section, although other cross-sectional shapes are included, and has a width of about 1.1 mm between the flat sides and a width of about 1.26 mm at the point, and extends about 1.5 mm below the bottom surface of base  32 .  
         [0040]     The slots referenced herein are preferably each about 1.5 mm in depth and are spaced apart about 2 mm in the three and six slot versions, while the slots in the eight-slot embodiment are spaced apart about 2 mm. The gap between walls (e.g., walls  51  and  53 ,  FIG. 4 ( b )) can vary from about 0.45 mm to about 0.90 mm. The pins  38  have a spacing of about 15.5 between their center lines, and the distance from the center line of the wire comb to the center line of the left pin  38  in  FIG. 6 ( b ) is about 7 mm, and is about 8.5 mm to the center line of the right pin.  
         [0041]     With the pin placement as shown and described above, it will understood that two wire combs can be positioned directly over one another on opposite side of a board, with the offset of the pins permitting one of the two combs to be turned 180 degrees.  
         [0042]     With reference to  FIG. 8 ( a ), four mounting holes  202 ,  204 ,  206 , and  208  are provided on the right end (denoted “A”) of board  100 . Two mounting holes  210  and  212  are respectively formed at the opposite end, “B.” Wire connection or electrical contact pads, shown at  104  and  106 , respectively, are also provided on circuit board  100 , along with the desired circuitry (not shown).  
         [0043]     FIGS.  8 ( b ) and  8 ( c ) show three wire combs  130  mounted in place on a circuit board  100 .  FIG. 8 ( b ) shows the top of circuit board  100 , and a wire comb  30  is mounted adjacent each end “A” and “B.”  FIG. 8 ( c ) shows the bottom of circuit board  100 , and another wire comb  30  which is mounted adjacent end “A”. At end “A”, the top-side wire comb  30  will have its pins  38  mounted within mounting holes  204  and  208 , where as the bottom mounted wire comb  30  will have its pins  38  mounted within mounting holes  202  and  206 . The third wire comb  30  is mounted adjacent end “B”, on the top side of board  100 , and its mounting pins  38  will fit in mounting holes  110  and  112 . It should be understood that additional sets of mounting holes could be provided at end “B”, or wherever else on board  100  it might be desired to employ a wire comb, even along the longer sides or inboard from either or both of the ends.  
         [0044]     A method of assembling a cable system according to embodiments of the present invention is now described. The appropriate wire combs  132 ,  134 ,  136  are fixedly inserted into the corresponding-holes in the PCB  100 . Any suitable adhesive can be used to hold the wire combs in place. The adhesive can be a viscous adhesive that cures either through chemical catalytic means, by a photo cure or by solvent evaporation. The preferred adhesive is a thin layer of a low bloom Cyanoacrylate.  
         [0045]     To connect the cable assemblies  112 ,  114  to the PCB  100 , the shield braid  152  from the cables is installed per  FIGS. 3 and 9 ( a ). Preferably the cable jacket end should be positioned no more than 8 mm from the board edge. The connection should be soldered and the shield braid should be trimmed as necessary. Shrink insulation may be used as necessary. The wires from the cable assemblies  112 ,  114  are then positioned in the wire comb  136  according the required connectivity. The wires from cables  104 ,  108  are similarly connected to the appropriate contacts. Once the various wires are in the appropriate slots of their respective wire combs, a fast dry adhesive as noted above, may be used along the top of the wire comb to secure the conductors. Preferably 100% shielding is maintained on all connectors with copper foil or a metal shell between the connector shell and the cable&#39;s braided shield. In a presently preferred embodiment, for use in a KVM system, the coax returns, sync ground, shield and drain wires are stripped and twisted together. Trimming of up to 25% of the shield braid strands is allowed. Strand ends must not be allowed to pierce through conductor insulation. FIGS.  9 ( b )- 9 ( e ) provide detailed views of the wires from cable  108  in wire comb  134 .  
         [0046]     With all wires positioned in wire combs and with of the electrical connections made, the entire assembly may be overmolded. There are preferably two overmolds, an inner overmold, as shown in FIGS.  10 ( a )- 10 ( b ), and an outer overmold, as shown in FIGS.  10 ( c )- 10 ( d ). Preferably an LDPE resin is used for the overmolds. The outer overmold assembly preferably uses a UL rated 94V-0 PVC resin.  
         [0047]     FIGS.  10 ( c )- 10 ( d ) show the structure of  FIG. 3  following a molding step where a molded outer jacket or covering  290  has been formed so that it extends around and encloses the elements shown above and described in  FIG. 3 . The molded outer structure is an integral, one piece covering that also encloses the ends of cables  120 ,  148 ,  146  and  126  (in  FIG. 10 ( c ), cables  120 ,  126  and  132  in  FIG. 10 ( d )). The moldedjacket  290  is preferably comprised of an LDPE resin, and comprises an over-molded structure that is molded in place around the overmolded circuit board (FIGS.  10 ( a )- 10 ( b )) and its connections, with the overmolded circuit board  192 .  
         [0048]     In presently preferred implementations, the molded encapsulation of circuit board, the wire combs, together with the cable ends preferably does not have a flashing that exceeds 4 mm at the cable jacket area. Similarly, the overmolded outer jacket  290  should have minimal pinched outer walls and minimal effects of heat distortion, and preferably does not exceed 6 mm from the inner mold wall.  
         [0049]     In some presently preferred embodiments of the present invention, the interior dimensions of the molded cover  290  can be about 51 mm long, about 23 mm wide, and about 8.6 mm thick, and with a 4 mm flashing would be about 55 mm long. The outer dimensions of cover  290  will be longer, wider and thicker as may be desired, such as, for example, about 92 mm long, about 31 mm wide and about 14 mm thick.  
         [0050]     Thus is described an improved wire mounting approach comprising use of a wire comb which, when mounted on a circuit board, will hold individual wires, space them apart a desired amount, hold them firmly in place, and permit the connecting (e.g., by soldering) of the individual wires to connections on the circuit board.  
         [0051]     In some aspects, the present invention comprises a wire comb mounting structure that can be fabricated to be mountable on a circuit board, preferably adjacent to the wire contacts thereof. The wire comb according to embodiments of the present invention can have a variety of constructions, not only to accommodate wire placement needs for a particular circuit board, but also to accommodate the size, type and number of individual wires and/or cables being mounted to the circuit board.  
         [0052]     The wire comb according to embodiments of the present invention can be formed to mount a signal individual wire or a plurality of individual wires, for example, three, six, eight or more. It is also within the scope present invention to use either a single wire comb or multiple wire combs, again depending upon the particular circuit board and the number of individual wires being mounted.  
         [0053]     In some embodiments, a seven-gap wire comb is preferably used to hold seven wires from a VGA plug, whereas a six-gap wire comb is preferably used to hold three wires from each of a PS/2 mouse and keyboard connector; and a three gap wire comb is preferably used to hold three wires from a USB connector.  
         [0054]     In addition, in other aspects, the present invention contemplates using wire combs on a variety of areas of a circuit board and on more than one side of a circuit board. The wire combs can be used on different parts or portions of the same side of a circuit board, as well as on opposite sides of circuit boards. The present invention also contemplates the use of multiple combs, and the use of combs in directly opposing positions on opposite sides of the board.  
         [0055]     Wire combs according to embodiments of the present invention can have a variety of sizes, designs and/or arrangements. One embodiment includes eight openings spaced out across the width of the comb. The openings can be designed to frictionally hold individual wires, or alternatively permit the insulating cover to snap-fit into an opening. It is also contemplated to use an adhesive such as those previously noted above as well as fast drying adhesives.  
         [0056]     In some other aspects, the present invention also contemplates a variety of openings in terms of location, spacing, size and shapes including as well single or multiple openings for engaging each wire.  
         [0057]     In further aspects, the present invention further comprises encasing the circuit board and the cable mounted firmly in a molded outer casing or jacket that will be a sufficient size to cover the circuit board thoroughly forming the board and cables into a unitary molded assembly.  
         [0058]     While the present invention has been described in detail and with reference to cable systems for use in KVM (Keyboard Video Mouse) systems. Those skilled in the art will realize that the invention is not limited to KVM cables or to cables for KVM systems.  
         [0059]     Although the drawings show particular wires being connected to particular contacts, it will be immediately apparent to those skilled in the art that the wiring in any particular system will depend on the circuitry and its functions.  
         [0060]     While the present invention has been described with respect to inline PCBs, those skilled in the art will realize and understand that the invention is not limit to such PCBs and can be used for fixed mounted circuit boards.  
         [0061]     While the present invention has been described in detail, and with reference to specific embodiments thereof, it will be apparent to those skilled in the art of their various modifications and variations can be made in the manufacture and practice of the present invention without departing from the scope and spirit of the invention. Other embodiments, modifications and changes of the present invention will readily occur to those skilled in the art, from their consideration of the foregoing specification and the embodiments set forth, which should be considered as exemplary only. Accordingly, it is not desired to limit the invention to the exact construction and operation illustrated and described, and all the suitable modifications and equivalents should be considered to be within the scope of the invention as set forth in the following claims.