Patent Publication Number: US-6663443-B1

Title: Lay-in electrical connector with a detachable tang

Description:
FIELD OF THE INVENTION 
     The present invention relates to electrical connectors and, in particular, to lay-in electrical connectors. 
     BACKGROUND OF THE INVENTION 
     Lay-in electrical connectors are frequently used for securing large gauge conductors that are stiff and difficult to handle as compared with smaller diameter conductors that are readily deformed and contorted for securement. Lay-in electrical connectors generally include a lug body having a channel-shaped wireway, a top screw-threaded lug cap received and captured within the wireway, and a binding screw extending through the lug cap to be tightened against a conductor or conductors laid in the wireway. The wireway is provided with opposed upstanding walls each having an inwardly-oriented groove that captures a corresponding one of opposite side flanges provided on the lug cap. The grooves of the wireway cooperate with the side flanges of the lug cap to resist upward movement of the lug cap as the binding screw is tightened. 
     The lay-in style of electrical connectors is characterized in that the lug cap may be separated from the lug body when a conductor is to be laid into place between the upstanding walls of the lug body. As a result, the conductor does not have to be forced into the entrance of the wireway. After the conductor is positioned in the wireway, the side flanges of the lug cap are engaged with the grooves of the wireway and the lug cap is slidingly shifted into position over the conductor. The binding screw is tightened to apply a clamping force to the inserted conductor that presses the conductor against the floor of the wireway. The clamping force creates an assembly of the lug cap and lug body. 
     Certain lay-in style electrical connectors include multiple wireways each capable of accepting a conductor. One significant disadvantage of multi-conductor lay-in electrical connectors is the multiplicity of components. Associated with each wireway is an independent lug cap carrying at least one binding screw. The electrical connector is typically shipped from the manufacturer as a group of loose components, which may become separated during shipment and lost. As a result, workers installing multi-conductor lay-in electrical connectors may lack all components needed for the installation. Even if all components are available, the worker must track the various components during assembly. Often, the components are misplaced or mislaid. Therefore, it is of considerable practical importance to maintain assembly of the parts of a lay-in electrical connector when it is not in use. 
     Multi-conductor lay-in electrical connectors include a tang that incorporates multiple mounting openings used to secure the electrical connector to a supporting structure or device with conventional fasteners. Such electrical connectors find use in the utility industry for attachment to, for example, a spade mount bushing on a transformer. Although the screw-threaded cap and connector body may be formed as extruded components, the tang must be machined in its entirety from metal stock. As a result, the tang is relatively expensive to manufacture. Moreover, the tang is typically welded to the connector body which adds a manufacturing step and increases the labor costs incurred to perform the welding operation. 
     Therefore, there is a need for a multi-conductor lay-in electrical connector having a tang that is removably coupled with the lug body and formed by extrusion, and for a device that can maintain the components of the lay-in electrical connector united with the lug body before installation. 
     SUMMARY OF THE INVENTION 
     The invention is related to a lay-in electrical connector configured to accept multiple conductors. According to the principles of the invention and in one embodiment, the lay-in electrical connector includes a body member or lug body having a plurality of dividing walls defining a plurality of conductor-receiving channels each capable of receiving a conductor, a plurality of cap members or lug caps each configured to be engaged with a corresponding one of the conductor-receiving channels, and a tang configured to be engaged with the body member. Each of the cap members has a binding screw capable of being tightened to capture the conductor in the conductor-receiving channel. The tang includes an attachment pad with at least one mounting hole and a plurality of fingers extending from a side edge of the attachment pad. Each of the plurality of fingers is positioned between adjacent ones of said dividing walls when the tang is engaged with the body member. When the binding screw is tightened, the conductor received within the corresponding one of the conductor-receiving channels is captured between one of the fingers and the binding screw of the cap member. In certain embodiments of the invention, at least the tang is formed by an extrusion process and, in other embodiments of the invention, the mounting holes in the attachment pad of the tang are formed during the extrusion process forming the tang. 
     Forming the tang by extrusion reduces the manufacturing costs for the multi-conductor lay-in electrical connector and expands the flexibility for its use. Moreover, in certain embodiments of the invention, the mounting holes of the attachment pad are created during the extrusion process so that the tang may be formed without any significant additional machining or drilling which reduces the expense of the manufacturing process. In addition, the electrical connector of the invention is free of welded joints because the tang is held in place by an assembly force supplied by the engagement between the binding screws and the conductor in the conductor-receiving channel. 
     According to the principles of the invention, a lay-in electrical connector is provided that includes a body member having a conductor-receiving channel capable of receiving a conductor and a cap member removably received in a portion of the conductor-receiving channel. The cap member has a binding screw capable of being tightened to secure the conductor positioned in the conductor-receiving channel. The electrical connector further includes a plug removably positioned in the conductor-receiving channel. The plug is configured to be contacted by the binding screw for captivating the cap member with the body member. 
     According to the principles of the invention, the removable plug reduces labor costs associated with installation of a lay-in electrical connector having at least one removable cap member or lug cap and simplifies the installation process. In particular, the removable plug permits the lug cap to be associated with the body member or lug body in a pre-assembled condition for storage and shipment after manufacture. To that end, the removable plug captivates the lug cap with the lug body without advancing the binding screw(s) to contact the lug body for holding the assembly together. As a result, the binding screw(s) are suspended in a position ready for securing a conductor in the conductor-receiving channel without withdrawing or otherwise moving the binding screw(s) after the plug is removed. After the lug cap is disengaged from the lug body and the plug is removed, the lug cap can then be re-engaged with the lug body in a position suitable for engaging the binding screws with the conductor without manipulating the binding screws to avoid the obstruction presented by the conductor during re-engagement. 
    
    
     The objects and advantages of the present invention will be further appreciated in light of the following detailed description and drawings in which: 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a disassembled perspective view of a multi-conductor lay-in electrical connector in accordance with the principles of the invention; 
     FIG. 2 is a perspective view of a portion of the electrical connector of FIG. 1 shown with the corresponding conductor absent from the conductor-receiving channel, with the lug caps engaged with the lug body, and with a disposable plug positioned in the conductor-receiving channel; 
     FIGS. 3A-3E are diagrammatic views illustrating assembly of the multi-conductor lay-in electrical connector of FIG. 1; 
     FIG. 4 is a perspective view of an alternative embodiment of a multi-conductor lay-in electrical connector in accordance with the principles of the invention; 
     FIG. 5 is a perspective view of an alternative embodiment of a tang for use with the multi-conductor lay-in electrical connector of FIG. 4; and 
     FIG. 6 is a perspective view of a removable plug according to the principles of the invention. 
    
    
     DETAILED DESCRIPTION 
     Although the invention will be described next in connection with certain embodiments, the invention is not limited to practice in any one specific type of lay-in style electrical connector. It is contemplated that the principles of the invention can be used with a wide variety of lay-in style electrical connectors. The description of the invention is intended to cover all alternatives, modifications, and equivalent arrangements as may be included within the spirit and scope of the invention as defined by the appended claims. In particular, those skilled in the art will recognize that the components of the invention described herein could be arranged in multiple different ways. 
     With reference to FIGS. 1 and 2, a lay-in electrical connector  10  of the invention is an assembly including a body member or lug body  12 , multiple cap members or lug caps  14  removably coupled with the lug body  12 , and a spade or tang  16  also removably coupled with the lug body  12 . The tang  16  is used to mount the electrical connector  10  in a low-resistance, current-carrying electrical connection with a support surface of a device (not shown), such as a transformer, capable of being energized. The electrical connector  10  operates to transfer or distribute electrical current from the energizeable device to multiple conductors  18 , typically either aluminum or copper, each secured in electrical continuity with the lug body  12  by a corresponding one of the lug caps  14 . 
     The lug body  12  includes a horizontal base wall  20 , a pair of vertical outer dividing walls  22 ,  24  extending away from the base wall  20 , and a plurality of, for example, three inner dividing walls  26 ,  28 ,  30  extending vertically away from the base wall  20 . The inner dividing walls  26 ,  28 ,  30  are positioned peripherally between the outer dividing walls  22 ,  24  and partition the transverse space between the outer walls  22 ,  24  into a plurality of open-ended wireways or conductor-receiving channels  32 ,  34 ,  36 ,  38 . The vertical ends of the outer and inner dividing walls  22 ,  24 ,  26 ,  28 ,  30  opposite the base wall  20  are not interconnected so that a corresponding one of the conductors  18  can be placed vertically into the corresponding one of the conductor-receiving channels  32 ,  34 ,  36 ,  38 , which is a feature characteristic of lay-in electrical connectors. The transverse spacing between adjacent pairs of dividing walls  26 ,  28 ,  30  is sufficient to permit vertical placement of the respective one of conductors  18  into each of the conductor-receiving channels  32 ,  34 ,  36 ,  38 , when the corresponding one of the lug caps  14  is removed. 
     The structure of the lug body  12  within conductor-receiving channel  32  is substantially identical to the structure within each of the conductor-receiving channels  34 ,  36 ,  38 . Therefore, the following description relating to conductor-receiving channel  32  is equally applicable to channels  34 ,  36 ,  38 . Extending upwardly away from the base wall  20  with conductor-receiving channel  32  is a pair of opposed shoulders  40 ,  42 . The opposed shoulders  40 ,  42  flank a flat-bottomed, slot-like passageway  44  that extends lengthwise along the conductor-receiving channel  32  and that is aligned generally parallel to the longitudinal centerline of channel  32 . The passageway  44  has a uniform width in a direction transverse to the conductor-receiving channel  32  that is less than a width of the conductor-receiving channel  32 . 
     With continued reference to FIGS. 1 and 2, provided on a side surface of inner dividing wall  26  and on an inwardly-facing side surface of outer dividing wall  22  are respective channels  46 ,  48  that open into conductor-receiving channel  32 . Each channel  46 ,  48  is spaced vertically upward from the corresponding shoulder  40 ,  42  and extends the length of the conductor-receiving channel  32 . The channels  46 ,  48  are confronting and are aligned substantially parallel with each other and relative to a longitudinal axis aligned with the centerline of the conductor-receiving channel  32 . Each channel  46 ,  48  is bounded upwardly by a respective downwardly-facing cam or contact surface  49 ,  50  (FIG. 2) angled with a downward inclination angle. 
     Each lug cap  14  is a generally rectangular body  52  having a planar upper surface  54  and an arcuate lower surface  56  that are connected by opposed side surfaces  58 ,  59 . Each lug cap  14  is configured to be removably associated with one of the conductor-receiving channels  32 ,  34 ,  36 ,  38 . To that end, a pair of side flanges  60 ,  62  project outwardly in opposite directions from the opposed side surfaces  58 ,  59  of each lug cap  14 . The side flanges  60 ,  62  are generally parallel and are of sufficient width and height to provide a sliding fit with the channels  46 ,  48  of the lug body  12 . Each of the side flanges  60 ,  62  has an upwardly-facing cam or contact surface  63 ,  64  inclined with an angle corresponding to the inclination angle of corresponding contact surfaces  49 ,  50 . When the lug cap  14  is engaged with the lug body  12 , the side flanges  60 ,  62  slidingly engage the channels  46 ,  48  in a direction parallel to the corresponding one of the conductor-receiving channels  32 ,  34 ,  36 ,  38  such that each of the side flanges  60 ,  62  is captured against vertical movement. The engagement between the contact surfaces  49 ,  50  and the contact surfaces  63 ,  64  facilitate assembly of the electrical connector  10  by promoting efficient transfer of the torque of binding screws (to be discussed below) to the conductor  18  and facilitate assembly of the components of the electrical connector  10 . After engagement, the arcuate lower surface  56  of each lug cap  14  spans, and provides an upper boundary for, the respective one of the conductor-receiving channels  32 ,  34 ,  36 ,  38  and overlies the corresponding passageway  44 . 
     With continued reference to FIGS. 1 and 2, each lug cap  14  includes a longitudinally-spaced pair of threaded openings  66 ,  68  each of which are configured to intermesh or mate with complementary threads on a corresponding one of the pair of binding screws  70 ,  71 . A vertical centerline of each threaded opening  66 ,  68  is oriented substantially orthogonal to a horizontal or longitudinal centerline of the conductor-receiving channels  32 ,  34 ,  36 ,  38  with which the respective lug cap  14  is associated, when the lug cap  14  is engaged with the lug body  12 . When the binding screws  70 ,  71  are advanced downwardly against the conductor  18  in the corresponding one of the conductor-receiving channels  32 ,  34 ,  36 ,  38 , the lug cap  14  moves upwardly relative to the lug body  12  and the respective pairs of contact surfaces  49 ,  50  and contact surfaces  63 ,  64  engage. It is appreciated that the lug cap  14  may include any number of threaded openings and associated binding screws without departing from the spirit and scope of the invention. 
     The tang  16  includes a generally rectangular attachment pad  72  and a plurality of, for example, four fingers or tines  74 ,  75 ,  76 ,  77  projecting outwardly and generally parallel to each other from one side margin or edge  78  of the circumference of the attachment pad  72 . The tines  74 ,  75 ,  76 ,  77  and the attachment pad  72  are formed as an integral structure by an extrusion process creating the tang  16 . The generally-rectangular tines  74 ,  75 ,  76 ,  77  are spaced in a transverse direction such that each tine  74 ,  75 ,  76 ,  77  is received within a corresponding one of the conductor-receiving channels  32 ,  34 ,  36 ,  38  when the tang  16  is engaged with the lug body  12 . To that end, the dimension of the tines  74 ,  75 ,  76 ,  77  and the spacing between the adjacent pairs of tines  74 ,  75 ,  76 ,  77  provides a snug fit with the respective passageway  44  of the conductor-receiving channels  32 ,  34 ,  36 ,  38  when the tang  16  is engaged with the lug body  12 . 
     With continued reference to FIGS. 1 and 2, a free end of each tine  74 ,  75 ,  76 ,  77  opposite the end attached to the attachment pad  72  includes a pair of side flanges  79 ,  80  that extend outwardly in opposite transverse directions. When the tang  16  is assembled with the lug body  12 , the side edge  78  of the attachment pad  72  contacts the dividing walls  22 ,  24 ,  26 ,  28 ,  30  of lug body  12  about one entrance to each passageway  44  and the side flanges  79 ,  80  of each tine  74 ,  75 ,  76 ,  77  engage the dividing walls  22 ,  24 ,  26 ,  28 ,  30  about the opposite entrance to the passageway  44 . The engagement prevents longitudinal movement of the tang  16  relative to the lug body  12 , which is useful before the conductors  18  are received in the conductor-receiving channels  32 ,  34 ,  36 ,  38  and the lug caps  14  are installed. In particular, the engagement is useful for securing the tang  16  against the influence of gravity if the electrical connector  10  is mounted with the conductor-receiving channels  32 ,  34 ,  36 ,  38  oriented vertically. 
     The attachment pad  72  further includes a plurality of, for example, four spaced-apart mounting holes  82  each configured to receive one of a corresponding plurality of fasteners (not shown) for attaching and electrically coupling the lay-in electrical connector  10  with the intended device. Mounting holes  82  are arranged with a suitable hole pattern. In certain embodiments, the hole pattern or arrangement for the mounting holes  82  may comply with standard NEMA bolt hole sizing and spacing. 
     The lug body  12 , lug cap  14 , and tang  16  may each be formed by an extrusion process from a billet of an electrically-conductive material, such as a metal alloy. Suitable metal alloys include, but are not limited to, high strength aluminum alloys such as  6061 -T 6 . Specifically, the lug body  12 , lug cap  14 , and tang  16  are produced by forcing a heated or cold billet of material to flow through a die in an extrusion press. The only features of the electrical connector  10  formed by a subsequent machining operation are the mounting holes  82  of the attachment pad  72  and the threaded openings  66 ,  68  that are drilled and tapped in the lug cap  14 . Otherwise, the electrical connector  10  is formed free of machining or drilling. 
     In use and with reference to FIGS. 3A-3E, an installation sequence is illustrated for the electrical connector  10 . Initially and with reference to FIGS. 3A and 3B, the lug caps  14  are removed from the lug body  12 . The tang  16  is moved generally in the direction of the arrow  83  to insert the tines  74 ,  75 ,  76 ,  77  between the dividing walls  22 ,  24 ,  26 ,  28 ,  30  and into the corresponding conductor-receiving channels  32 ,  34 ,  36 ,  38 . It is appreciated that the mounting holes  82  of the attachment pad  72  may be attached to a mounting surface on an associated energizeable device before performing the installation sequence. Next and as shown in FIG. 3C, the bare end of conductor  18  is laid vertically, in the general direction of arrow  84 , between the dividing walls  22  and  26  into conductor-receiving channel  32  and into contact with an upper surface of tine  74 . With reference to FIGS. 3D, the lug cap  14  is slidingly coupled with the lug body  12  by movement in the general direction of arrow  86  so that the side flanges  60 ,  62  are engaged with the channels  46 ,  48 . With reference to FIG. 3E, the binding screws  70 ,  71  are advanced against the conductor  18  to secure the conductor  18  with a binding force or tightening torque that also fixes the relative positions of the tang  16 , lug body  12  and lug cap  14 . A typical binding force is on the order of about 500 inch-pounds. The steps shown in FIGS. 3C-3E are repeated to place conductors  18  in the remaining conductor-receiving channels  34 ,  36 ,  38 . 
     With reference to FIG. 4 in which like reference numerals refer to like features in FIGS. 1 and 2, a tang  90  for use with lay-in electrical connector  10  includes an attachment pad  92  and a pair of substantially parallel tines  94 ,  96  extending outwardly from a side edge  98  of the attachment pad  92 . The tines  94 ,  96  are joined at one end by an integral connecting member  100  so as to define a generally-rectangular opening  102  dimensioned and shaped to receive therein one of the inner dividing walls  26 ,  28 ,  30 . The tines  94 ,  96  of the tang  90  are received by an adjacent pair of conductor-receiving channels  32 ,  34 ,  36 ,  38  when the appropriate pair of lug caps  14  is removed. Provided in the attachment pad  92  is a plurality of, for example, four mounting holes  104 . 
     With reference to FIG. 5 in which like reference numerals refer to like features in FIG. 4, a tang  110  for use with lay-in electrical connector  10  includes an attachment pad  112 , a pair of substantially parallel tines  114 ,  116  extending outwardly from a side edge  118  of the attachment pad  112 , and an integral connecting member  120  joining one end of the tines  114 ,  116  to form a generally-rectangular opening  122 . Provided in the attachment pad  112  is a plurality of, for example, four mounting holes  124  formed in a spaced pattern during an extrusion process forming the tang  110 . To that end, the tang  110  is extruded as an extruded body by forcing a hot billet to flow through a die over a mandrel or arbor positioned centrally in the die. The mandrel is suitably shaped to provide the pattern of mounting holes  124 . After forming, each extruded body is cut to a desired length to provide individual tangs  110 . In certain embodiments, the hole pattern for the mounting holes  124  may comply with standard NEMA bolt hole sizing and spacing. 
     The lay-in electrical connector  10  of the invention may be constructed in accordance with American National Standards Institute (ANSI) or Underwriters Laboratories standards (UL), if it is contemplated that the invention will be used in the United States of America. Other standards are applicable in other countries, such as standards promulgated by the Canadian Standards Association (CSA). It is appreciated that the features of the electrical connectors may be scaled in size to correlate with a gauge of conductor or range of gauges being secured. 
     The lay-in electrical connectors of the invention have various advantages over conventional lay-in electrical connectors for multiple conductors. Specifically, in one embodiment, all three primary components of the lay-in lug, namely, the connector body, the screw-threaded cap and the tang(s), are formed by an extrusion process so that any machining is limited to slicing the appropriate extruded form and removing any burrs. In other embodiments, the machining is limited to providing mounting holes in the attachment pad of the tang. 
     In addition, the electrical connectors of the invention are free of welded joints because the tang is held in place by an assembly force supplied by the binding screws securing the conductor in the conductor-receiving channel. The assembly force mechanically interlocks each lug cap with the lug body and, by pressing each conductor toward the base of its corresponding conductor-receiving channel, interlocks the fingers of the tang with the lug body. 
     In addition, the extruded tangs of the invention reduce the manufacturing costs for the multi-conductor lay-in electrical connector and expand the flexibility for its use. In certain embodiments of the invention, the mounting holes of the attachment pad are created during the extrusion process so that the tang may be formed without the need for additional machining or drilling thereby decreasing the expense of the manufacturing processes. 
     With reference to FIGS. 2 and 6, a disposable plug element or sleeve  130  is positioned within conductor-receiving channel  32  of the electrical connector  10  before conductor  18  is positioned within channel  32 . It is appreciated by a person of ordinary skill in the art that each of the conductor-receiving channels  32 ,  34 ,  36 ,  38  may be provided with one of the sleeves  130 . The sleeve  130  is formed from any suitable material including, but not limited to, a polymer resin. The sleeve  130  permits the electrical connector  10  to be stored and transported in a pre-assembled state, after manufacture, in which the lug body  12 , lug caps  14  and tang  16  are mechanically coupled as an assembly. In the depicted embodiment, the sleeve  130  includes a generally cylindrical, tubular side wall  132  and a pair of rectangular support members  134 ,  136  extending diametrically between differing portions of the side wall  132 . An upper curved surface of the sleeve  130  is contacted by a leading tip of each of the binding screws  70 ,  71  and a lower curved surface of the sleeve  130  contacts tine  74  of the tang  16 . The support members  134 ,  136  mechanically strengthen the side wall  132  to prevent collapse of the sleeve  130  when a radial force is applied to the side wall  132  by the binding screws  70 ,  71 . 
     The force applied by the binding screws  70 ,  71  to the sleeve  130  prevents, during storage and shipment, sliding movement of the respective lug cap  14  relative to the lug body  12  and/or disassociation of the tang  16  from lug body  12 . At the point of installation, the lug cap  14  and sleeve  130  are removed from the lug body  12 . After removal of sleeve  130 , the tip of the binding screws  70 ,  71  are spaced from the tine  75  of the tang  16  by a distance to provide sufficient clearance for re-engaging the lug cap  14  with the lug body  12  while the conductor  18  is present in conductor-receiving channel  32  and without repositioning the binding screws  70 ,  71  to clear the exterior of the conductor  18  as the lug cap  12  is re-engaged with lug body  12 . It is appreciated that the sleeve  130  may have other alternative constructions, such as a vertical post extending between the respective tips of the binding screws  70 ,  71  and the tine  74 , without departing from the spirit and scope of the invention. It is also contemplated by the invention that the sleeve  130  may be utilized in other types of lay-in electrical connectors, including those having removable lug caps and also lacking a removable tang. 
     In use, the lay-in electrical connector  10  is pre-assembled by mechanically coupling each of the lug caps  14  and the tang  16  with the lug body  12  using a sufficient number of sleeves  130  corresponding to the number of lug caps  14 . At the point of installation, the attachment pad  72  of the lay-in electrical connector  10  is mounted with conventional fasteners to a device, such as a transformer, capable of being energized. The sleeve  130  is removed from the conductor-receiving channel  34  and the corresponding lug cap  14  is removed. The stripped end of the conductor  18  is positioned in the conductor-receiving channel  34  and the lug cap  14  is re-engaged with the lug body  12 . The binding screws  70 ,  71  are advanced using a suitable driving tool to press the conductor  18  against tine  75  of the tang  16 . The sleeve  130  may be discarded after removal. The sequence is repeated to place conductors  18  in each of the remaining conductor-receiving channels  34 ,  36 ,  38 . 
     The sleeve operates to reduce labor costs associated with installation and simplifies the installation process. In particular, the sleeve permits the electrical connector to be shipped in a pre-assembled state, yet each lug cap is captivated by the sleeve with the lug body. In addition, the sleeve positions or suspends the associated binding screws in a withdrawn position ready for securing a conductor in the corresponding conductor-receiving channel. It is appreciated that the removable plug may be utilized with any electrical connector having one or more removable lug caps associated with a lug body. 
     With continued reference to FIG. 6, detents or tabs  140 ,  142  may provided at one longitudinal end of each lug cap  14 . The tabs  140 ,  142  project outwardly in opposite transverse directions from respective upper corners of lug cap  14 . It is understood by a person of ordinary skill that the lug cap  14 , depicted as engaged with conductor-receiving channel  32  of the lug body  12 , may be engaged with one of the other conductor-receiving channels  34 ,  36 ,  38 . The tabs  140 ,  142  contact respective side edges of corresponding ones of the outer dividing walls  22 ,  24  and inner dividing walls  26 ,  28 ,  30 . The tabs  140 ,  142  prevent unintentional or inadvertent sliding disengagement of the lug cap  14  from the lug body  12  in situations in which the electrical connector  10  is mounted with the conductor-receiving channels  32 ,  34 ,  36 ,  38  oriented vertically. As shown in FIG. 6, the tabs  140 ,  142  prevent sliding movement of the lug cap  14  in a direction away from the attachment pad  72 . 
     While the present invention has been illustrated by a description of various embodiments and while these embodiments have been described in considerable detail, it is not the intention of the Applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of Applicants&#39; general inventive concept. The scope of the invention itself should only be defined by the appended claims, wherein we claim: