Patent Publication Number: US-6705884-B1

Title: Electrical connector apparatus and method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to provisional application Ser. No. 60/174,446, filed Jan. 5, 2000 and provisional application Ser. No. 60/149,117, filed Aug. 16, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to electrical connectors. In specific embodiments, the subject invention pertains to an electrical connector for coupling to an insulated electrical coaxial cable or single conductor cable. In a typical connector, the end of the wire is stripped of insulation and the bare wire is inserted into a connector where it can be soldered or clamped or otherwise attached to the connector. 
     U.S. Pat. No. 5,403,201 discloses electrical connectors of the type including a center pin. The center pins shown in the U.S. Pat. No. 5,403,201 are of solid conductive material and engage the center wire of an electrical conductor by piercing the wire if it is multi-strand or engaging it on the side if it is single strand. In the latter case, the electrical connection can be quite good but necessarily only as good as the area of contact between the center pin of the electrical connector and the single strand wire of the electrical conductor and the pressure of engagement at the area of contact. 
     It is an object of the present invention to improve the center pin type of electrical connector so as to increase the integrity of the electrical connection between the center pin of the connector and the single strand wire of an electrical conductor while at the same time allowing the use of the connector with electrical conductors having multi-strand center wires. 
     BRIEF SUMMARY OF THE INVENTION 
     The subject invention pertains to an electrical connector and a method of coupling an electrical connector to an insulated electrical conductor. An electrical connector in accordance with the invention can comprise a housing and an electrically conductive center pin or prong mounted thereto for engaging the center wire of an insulated electrical conductor. The attachment of the center pin or prong to the housing is such that the center pin is electrically insulated from the housing. The housing can incorporate a center bore with the conductive center pin mounted therein such that an end of an insulated electrical conductor can be inserted into the bore. This center bore can, in certain embodiments, help to guide an insulated electrical conductor into engagement with the center pin. Preferably, the center pin is mounted in the housing such as to protrude toward the open end of the center bore. The center pin can be of solid design or can have one or more hollow portions. In a specific embodiment, the center pin is hollow and open at its exposed end for engaging the center wire of an insulated electrical conductor. Preferably, but not necessarily, the hollow portion of the center pin also incorporates one or more longitudinal slits extending along its side wall. These slits can allow for expansion of the end of the hollow portion of the center pin upon receipt of an electrical conductor which, for example, may be larger in outer diameter than the inner diameter of the hollow end of the center pin. The edge of the receiving end of the hollow portion of the center pin can be beveled and/or sharpened to enhance the ability of the hollow portion of the center pin to squeeze between the center conductor of the insulated electrical conductor and the adjacent insulation layer. 
     The subject electrical connector can also be utilized with coaxial cable or other insulated electrical conductors which incorporate a center conductor and an outer electrical conductor concentric with such that the outer electrical conductor is separated from the center conductor by a layer of insulation. In a specific embodiment for use with coaxial cable, a center pin makes electrical contact with the center conductor of the coaxial cable and the housing is provided with a means for making electrical contact with the outer electrical conductor. For example, one or more clamping members can be incorporated in the subject electrical connector which can penetrate the outer layer of insulation and make electrical contact with the outer electrical conductor. In an alternative embodiment of the subject invention, the center pin or prong can be substituted for by stripping the insulated electrical conductor such that the center conductor protrudes from an otherwise flush end of the insulated electrical conductor and projects into the connector housing in the place of the center pin. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded view of an electrical connector and a portion of a coaxial cable in accordance with the present invention. 
     FIG. 2 is an exploded view of the electrical connector of FIG. 1 but looking in the opposite direction and having the coaxial cable inserted into the housing cap which has been sectioned for clarity. 
     FIG. 3 is a sectional exploded view of the electrical connector of FIGS. 1 and 2. 
     FIG. 4 is a sectional view of the electrical connector of FIG. 3 having a coaxial cable end attached thereto. 
     FIG. 5 is a perspective view of another embodiment of a coaxial cable connector in accordance with the present invention. 
     FIG. 6 is an unexploded sectional view of the connection of FIG.  5 . 
     FIG. 7 is a sectional view of the embodiment of FIGS. 5 and 6 having the cable attached thereto. 
     FIG. 8A illustrates a side view of a conductive pin in accordance with the subject invention, incorporating a hollow portion having a single slit. 
     FIG. 8B shows an end cross-sectional view of the hollow portion of the pin shown in FIG.  8 A. 
     FIG. 9A illustrates a side view of a conductive pin in accordance with the subject invention, incorporating a hollow portion having two slits. 
     FIG. 9B shows an end cross-sectional view of the hollow portion of the pin shown in FIG.  9 A. 
     FIG. 10 illustrates a cross-sectional view of an electrical connector in accordance with the subject invention. 
     FIG. 11 is a perspective view of an electrical connector in accordance with the present invention. 
     FIG. 12 is a rear perspective view of the electrical connector of FIG.  11 . 
     FIG. 13 is a side sectional view of the electrical connector of FIGS. 11 and 12 having an electrical conductor being inserted thereinto. 
     FIG. 14 is a sectional view of the electrical connector of FIG. 13 having an electrical conductor attached thereto. 
     FIG. 15 is a sectional view taken through a second embodiment of an electrical connector of the present invention having an electrical conductor inserted into the connector bore. 
     FIG. 16 is a sectional view of the electrical connector of FIG. 15 having an electrical conductor attached thereto. 
     FIG. 17 is a sectional view taken through a third embodiment of an electrical connector of the present invention having an electrical conductor inserted into the connector bore. 
     FIG. 18 is a sectional view taken through an embodiment of an electrical connector of the present invention having an aperture in the insulated base through which a protruding inner conductor of a coaxial cable can pass. 
     FIG. 19 is a sectional view of the electrical connector of FIG. 18 having an electrical conductor attached thereto. 
     FIG. 20 shows an end view of an electrical connector in accordance with the subject invention having eight clamping arms which have been manipulated into the clamped position. 
     FIG. 21 shows a specific embodiment of an individual clamping arm broken away from the housing. 
    
    
     DETAILED DISCLOSURE OF THE INVENTION 
     Referring to FIGS. 1-4 of the drawings, an electrical connector  10  in accordance with the subject invention, especially adapted for use with a coaxial cable  11 , is illustrated. The coaxial cable  11  has a center conductor  12 , a surrounding concentric insulation  13 , a concentric conductive wire braid or sheath  14  surrounding the insulation  13 ; and an outer insulation  15  covering the conductive sheath  14 . Connector  10  can be adapted to connect a variety of types and sizes of coaxial cables to a variety of plugs, jacks, and connectors, all referred to herein as electrical connectors. Illustrated in FIGS. 1-4 for purposes of describing a specific embodiment of the subject invention is the male part of a 75 ohm coaxial F-connector. Connection of the coaxial cable  11  to connector  10  can be accomplished without solder and without the need to strip the insulation cover  15  from the cable. 
     Connector  10  as illustrated in FIGS. 1-4 includes a connector housing  16  having a cylindrical cable attaching portion  17  which external threads  18  defining a first chamber  20  and a cylindrical housing portion  25  with internal threads  26  defining a second chamber  24 . An electrically conductive pin  19  is mounted to an insulation base  22  within the housing  25  with the base  22  abutting and being secured to a wall portion  25 A. The conductive pin  19  has a tapered prong  21  extending axially into the bore defining the first chamber  20  and also has a cylindrical prong  23  extending axially into the bore defining the second chamber  24 . Electrically conductive arms  27  extend axially from the cable attaching portion  17  of the housing  16 . Each arm has pointed contacts  28  which are also electrically conductive. A plurality of clamping arms  27  are contemplated but a single arm can perform the operation of attaching the coaxial cable  11 . A locking cover  30  is a generally cylindrical conductive member having internal threads  31  adapted to engage the external threads  18  of the connector body portion  17 . The cap  30  has a central bore to receive the coaxial cable and an annular, frustoconically angled wedging portion  32  formed therein. FIG. 3 also shows a cup-shaped insulation covering  29  received within the connector housing  16  which provides extra security against contact of the conductive sheath  14  with the connector body  16  metal portions in the event a stray strand of wire from conductive sheath  14  should extend from the cable  11 . 
     In operation, the tip of the coaxial cable  11  does not have any of the insulation stripped from the conductors  12  or  14  as is normally required to connect a coaxial cable to a connector. The undisturbed end of the coaxial cable  11  is slidably inserted between the clamping members  27  and into the bore  20 . Sufficient force is provided to push the cable  11  onto the prong  21  and into electrical contact with the center conductor  12 . The electrical conductive contact with the coupling stem portion  19  provides electrical continuity to the probe  23 . The connector  10  can then be attached to an electrical apparatus, such as a television set or the like, or to another coaxial cable. 
     Once the coaxial cable  11  is pushed into the bore and attached into electrical contact with the prong  21 , the ends of the arms  27  may be clamped to drive the pointed contacts  28  through the outer insulation  15  into the conductive sheath  14 . This may be accomplished manually, by hand or with pliers, in clamping the ends of the arms  27  to force the pointed contacts  28  through the outer insulation  15  of the coaxial cable  11  into the concentric conductive sheath  14  to make an electrical contact therewith. 
     Alternatively, and in carrying out the same function, the ends of the arms  27  may be clamped by installing the housing cap  30  onto the threads  18  of the housing portion  17  so that wedging portion  32  drives against the ends of the clamps to drive the pointed contacts  28  through the outer insulation  15  and into the conductive sheath  14 . If done manually, the next step is to maintain the cable and the arms  27  in contact by, for example, threading the cap into place or utilizing the heat shrink embodiment, as shown in FIGS. 5,  6 , and  7 . 
     Turning now to FIGS. 5,  6  and  7 , another embodiment of a coaxial cable connector is illustrated in which an electrical connector  35  has an electrically conducting connector body  36 . In FIG. 7, the connector  35  has a coaxial cable  11  attached to one end thereof. The other end of the connector  35  has internal threads  37  with a center conductor  39  having a cylindrical conductor portion  38 . In this embodiment, a heat shrinkable insulating sleeve  40  is attached to the conductive connector housing portion  41 . A pointed prong  43  on the stem  39  is disposed in a chamber  42 . The pointed prong  43  is provided for insertion into electrical contact with the center conductor  12  of a coaxial cable  11 . A plurality of clamping arms  44  are connected to the conductive housing  41  and each arm  44  has a pointed prong  45  extending radially inward from the end thereof. 
     Coaxial cable  11  has electrical insulation  13  around the center conductor  12  which is covered by the concentric conductive sheath  14  which in turn is wrapped in insulation cover  15 . In operation, the coaxial cable  11  end is inserted into an opening  46  in the insulation  40  between the clamping arms  44  and prongs  45 . The prong  43  is driven into or continuously adjacent the center conductor  12  thereby making electrical contact therewith. 
     The center conductor  12  on coaxial cable is sometimes a single conductor wire and sometimes is formed of multiple strands so that the prong  43  will sometimes be driven into the multiple strand wire and at other times be directed adjacent to the single wire conductor  12 . 
     Once the cable  11  is inserted and is in conductive contact with the prong, the arms  44  are clamped manually by hand or with a tool so as to cause the pointed prongs  45  to pierce the outer insulation  15  and make conductive contact with the conductive sheath  14 . Alternatively, the heat shrinkable insulation  40  is heated which causes it to shrink tightly onto the housing  41  on onto the cable  11  and the arms  44 . This shrinkage can push the pointed prongs  45  of arms  44  through the outer cover  15  and into electrical contact with the conductor member  14 . In the case of the alternative and to further assure proper contact, the insulation  40  can be pressed by the assembler onto the clamp members  44  to set the prongs  45  through the insulation  15  and into the conductor  14 . The insulating sleeve  40  thus holds the connector  35  to the cable  11  while forming an insulation for the tip of the cable. The arms  44  also lock into the cover  15  to hold the cable in place with the conductive prong  43  making contact with the conductor  12  of the cable  11 . This provides the center conductor  38  with a contact with the cable  11 . The prongs  38  and  43  are mounted to an insulating member  47  which is attached to a wall  36 A of the body  36 . 
     Referring to FIGS. 8A,  8 B,  9 A, and  9 B, specific embodiments of a pin which can be utilized with respect to the electrical connectors of the subject invention is shown. For example, either pin shown in FIGS. 8A and 9A, or variations thereof, can be incorporated with the electrical connectors shown in FIGS. 1-4 and FIGS. 5-7. Both FIGS. 8A and 9A show side views of pins having a hollow portion on one end for receiving an electrical conductor and a solid portion for connecting with and an external apparatus on the other end. Other pin embodiments are possible which, for example, have a solid portion at each end of the pin (as in FIGS. 1-4) or have a hollow portion at each end of the pin. In addition, the entire pin can be hollow if desired. Preferably, the hollow portion of each pin can have one or more slits. The number, lengths, and widths, of the slits can vary depending on the application. FIG. 8A shows a slit which extends about half the length of the hollow portion of the pin, while FIG. 9A shows two slits which extend essentially the entire length of the hollow portion of the pin. FIGS. 8B and 9B show end views of the hollow portions of the pins shown in FIGS. 8A and 9A, respectively. These slits can allow the hollow portion to expand to just the right size to receive an electrical conductor such that a good electrical contact can be made. 
     FIG. 10 shows an electrical connector in accordance with the subject invention. This connector incorporates a pin  120  which has a hollow portion at each end for engaging a center conductor  124  of a coaxial cable  123 . In another embodiment, pin  120  can be designed, as in FIGS. 15 and 16, to accept a center conductor of an insulated wire. In addition, one or both ends of pin  120  could be a solid pin as shown in FIGS. 1-4, depending on the application. Pin  120  is attached to housing  111  via base  121  which electrically isolates pin  120  from housing  111 . In the embodiment shown in FIG. 10, base  121  extends to the edge of the bore where clamping arms  113  protrude from housing  111 . Narrowing the axial length of base  121  in this embodiment can allow a shorter length from the tips  133  of clamping arm  113  to the center of housing  111 , such that propagation losses can be reduced. The reduction in propagation losses can potentially enable the use of the connector for higher frequency signals. Pin  120  is shown as a solid pin through the region of base  121 , but could be hollow through a portion of, or all of, this region. The width of base  121  can be reduced to optimize the performance of the connector. As the width of base  121  is reduced, the width of housing  111  can also be reduced accordingly. 
     Preferably, a cover or cap can be used to, for example, protect the electrical connections made and/or help maintain clamping arms  113  in position once they have penetrated insulation layer  129  to make electrical contact with conductor  127 . In the embodiment shown in FIG. 10, cap  190  is shown as a snap-on cap. Lip  191  of cap  190  is designed to settle into indentation  192  on housing  111 . Other designs for cap  190  can be utilized depending on the application. If desired, o-rings, or other equivalent means, can be incorporated with the use of cap  190  to protect the connection from moisture and other environmental conditions and/or to enhance the performance of the cap. Alternatively, the connector shown in FIG. 10 can be utilized without cap  190 . 
     In a further variation, the arrangement of FIG. 10 may be provided with a sleeve  193  which fits over the arms  113 A after they have been clamped into place in the cable  123 A in order to secure the arms to the cable  123 A. Sleeve  193  can be made, for example, of metal, or other appropriate materials. In that arrangement the cap  190 A can be just like the cap  190  or it can be a sleeve or a cap of heat shrink material, that would for example, seal the connection between the cable and the connector. In a manufacturing operation in which the cable is connected to the connector, the cap  190 A could be of molded plastic which would secure the arms to the cable  123 A in which case the use of the ring  193  might not be necessary. In addition, rubber molded coverings can be utilized with the subject connector to cover and hold clamping arms  113  in place. 
     Referring to FIGS. 11-14, a specific embodiment of an electrical connector in accordance with the subject invention is illustrated. Electrical connector  110  has a housing  111 . Preferably, as shown in FIGS. 11-14, housing  111  can have a bore  112  extending thereinto. An insulated electrical conductor can be guided into bore  112  to assist in aligning pin or prong  120  with the center conductor of the insulated electrical conductor. One or more clamping arms  113  can extend from end  114  of housing  111 . Clamping arms  113  can be pressed into the outer insulation layer  129  of an insulated electrical conductor  123 , the center conductor of which is in contact with center pin  120 , to make electrical contact with a second electrical conductor  127  of conductor  123 . A cover and/or means for holding clamping arms  113  in place can be incorporated with the subject connector. In the embodiment shown in FIGS. 11-14, external threads  115  can be located on housing  111  to receive a threaded cap. Other types of caps and cap attachment mechanisms are also possible. Insulated base  116  can attach center prong  120  to the housing such that the center pin is electrically insulated from housing  111 . 
     Once electrical contact is made between center pin  120  and center conductor  124 , and optionally between housing  111  and second conductor  127 , a variety of designs can be used to enable the connection of connector  110  to other apparatus. For example, a symmetric design can be utilized to connect to a second insulated electrical conductor identical to conductor  123  to form a coupler. A second pin  122  can extend from the housing and be in electrical contact with pin  120  such that pin  122  is in electrical contact with center conductor  124 . Other means for allowing an external apparatus to make electrical contact with center conductor  124  can also be used. In the embodiment shown in FIGS. 11-14, pin  122  allows electrical contact with center conductor  124  while housing  111  allows electrical contact with second conductor  127 . Specifically housing  111  can have a second bore  117 , which can extend from the opposite side of the base  116 . Second bore  117  can have internal threads  118  for attaching the connector to an externally threaded member. 
     Center pin or prong  120  can extend axially from housing  111  and, as shown in the embodiment shown in FIGS. 11-14, can extend past the end of bore  112 . Alternatively, the end of prong  120  can be within bore  112 . Prong  122  can be attached to base  121 , insulating prong  122  from the outer conductive portion of housing  111 . Prongs  120  and  122  can be one continuously conductive prong, as illustrated in FIGS. 13 and 14. According electrical contact can be made between the center conductor contacted by prong  120  and a electrical conductor contacting prong  122 . Attaching prong  122  may be a solid member, as illustrated, or can be a hollow prong similar to prong  120 . 
     Conductive prong  120  is shown in FIG. 13 just prior to engaging with insulated electrical conductor  123  having a conductor  124  surrounded by a concentric insulating layer  125 , concentric conductor  127 , and outer concentric insulation layer  129 , such that a hollow portion of prong  120  will surround and makes electrical contact with center conductor  124  as end  126  of conductor  123  is inserted into bore  112 . Prong  120  has a hollow portion beginning at prong end  128  and extending at least as far as conductor  123  may be inserted. Preferably, as shown in FIGS. 11-14, the hollow portion of prong  120  can have one or more slits extending from end  128  of prong  120  as far up as desired. The slits along the sides of the prong  120  can form one or more prong segments  131 . Preferably, prong  120  has two prong segments  131  with sharpened edges and can expand to accommodate different sizes of electrical conductors  124  located inside the insulation. The edge  128  of end  126 , namely the end edges of prong segments  131 , can be sharpened and/or beveled in either direction, to enhance the ease of insertion between center conductor  124  and insulation layer  125 . 
     At least one, and preferably all arms  113  have an insulation engaging tip  133 . This tip can be angled and/or have a sharpened edge, as shown in FIGS. 11-14, for penetrating and clamping onto the insulated wire  123 . Once the insulated conductor  123  is engaged with conductive prong  120 , as show in FIG. 14, clamping arms  113  can be pushed toward insulated conductor  123  such that tips  133  enter insulation layer  129  of the wire  123 , to make electrical contact with conductor  127 . This can be done, for example, manually with a person&#39;s fingers, with a pair of pliers, or with a special tool for driving tips  133  into the insulation. 
     The driving tips of the clamping arms can take on a variety of shapes to optimize electrical contact with conductor  127  and the ability to withstand pulling forces on conductor  123  with respect to connector  110 . Referring to FIG. 21, a single clamping arm  113  broken away from housing  111  is shown. The pointed end  133  of clamping arm  113  can have a variety of shapes, in order to optimize one or more operational characteristics of the subject electrical connector. In the embodiment shown in FIG. 21, pointed end  133  is shaped such that as the clamping arms are manipulated to cause the piercing of the outer insulation, the sides  134  of the clamping arms come in contact with the adjacent clamping arms such that contiguous encasement with adjacent clamping arms act to prevent further penetration of the pointed end  133 . 
     FIG. 20 shows an end view of an embodiment having eight clamping arms, as shown in FIG. 21, which have been clamped into place. Dashed line  200  represents the position of surface  201  of the clamping arms. Preferably, the clamping arms  113  are designed such that surface  201  contacts the surface of the outer insulation of the coaxial cable when the clamping arms are clamped in place. In this embodiment, surface  201  is curved to match and engage the circumference of the outer insulation of the coaxial cable. In this way, the clamping arms  113  contact the outer insulated conductor of the coaxial cable over almost its entire circumferential surface. This large surface area of contact can help to hold the coaxial cable in place. If desired, knurling or other alterations to the surface texture of surface  201  can be made to increase the frictional forces between surface  201  and the coaxial cable. The distance past surface  201  which pointed end  133  protrudes, and therefore will penetrate into the coaxial cable, can be selected such as to optimize one or more performance characteristics of the subject connector. For example, the amount of protrusion of end  133  can be adjusted such that end  133  contacts but does not penetrate the conductive sheath, just barely penetrates through the conductive sheath, or penetrates through the conductive sheath and into the inner insulation of the coaxial cable. 
     The curve of the end  133  can also be selected to optimize the performance of the connector. In FIG. 20, the curve of end  133  is selected such that the eight ends form a circular pattern of deepest penetration into the conductive sheath of the coaxial cable. This circular pattern can help to reduce reductions in the quality of the electrical signal caused by the electrical connector. The dotted circle in the center of FIG. 20 represents the approximate location of the inner conductor of the coaxial cable. The shape of the protruding end  133  can also be adjusted to optimize the degree to which the clamping arms can hold the coaxial cable in the connector, to assist when the cable is pulled with respect to the cable. 
     Preferably, a cap can be used to hold arms  113  in place once they are driven into the insulation. This cap can be designed to further push tips  133  into the insulation as the cap is positioned. Such a cap can utilize one of a variety of designs. For example, the cap can slide over clamping arms  113  and lock into place on housing  111 , thread onto the housing, fold together and snap, or utilize a heat shrinkable material, to hold itself in position. In a specific embodiment, a closure cap can have insulated conductor  123  passing there through, and fit over the arms  113  to attach to external threads  115 , holding the clamping arms  113  in position with respect to insulated conductor  123 . In a specific embodiment of the subject connector, losses associated from the connector can be reduced by having no bore  112  but, rather having clamping arms  113  extend directly from the portion of housing  111  adjacent base  121  such as to reduce the distance between tips  133  and base  121 . If desired, a ridge can be provided for a snap-on cap to snap onto and hold arms  113  in place. 
     Turning to FIGS. 15 and 16, a specific embodiment of an electrical connector  140  for coupling to a center conductor having an outer insulation layer is illustrated. The connector shown in FIGS. 15 and 16 has a housing  141  having a bore  142  in one end thereof and a bore  143  extending into the other end of the housing  141 . The housing can have external threads  144  on one end thereof and internal threads  145  extending into the bore  143 . A center conductive prong  146  extends axially into the bore  142  and a conductive prong  147  extends axially into the bore  143 . Prongs  146  and  147  are electrically connected and can be one continuous prong supported in the housing  141  by collar  141 A. Prong  146  has a hollow portion  146 A extending from end  150  to receive a center conductor  124 . The hollow portion  146 A of prong  146  is not required to have but may have a single slit  151 , or a plurality of slits in the side thereof to, for example, allow prong  146  to expand as a center conductor enters. Slits  151  can extend the entire length of the hollow portion of prong  146  or any portion thereof. If prong  146  has two or more slits, the slits can divide the end of the prong  146  into a plurality of segments  152 . In the embodiment shown in FIGS. 15 and 16, end  150  has been beveled inwardly to allow the segments to more easily drive in between center conductor  124  and insulation layer  125  of the insulated electrical conductor  123 . If desired, end  150  can be beveled in the opposite direction or sharpened on both sides. 
     The insulated electrical conductor  123  is shown being inserted into bore  142  in FIG. 15, and attached to connector  140  in FIG.  16 . The portion of housing  141  surrounding bore  142  can be sufficiently large in diameter to allow the insulated conductor to be inserted into bore  142  with the hollow portion of prong  152  squeezing between center conductor  124  and insulation layer  125 . Preferably, the open end portion of housing  141  surrounding bore  142  can have one or more slits  153 A extending from the end of housing  141  which can create one of more clamping arms  153 . Preferably, slits  153 A can extend up to the threaded portion  144  and may extend into the threaded portion  144 , if desired. Extending from housing  141 , clamping arms  153  can be dimensioned to allow the insulated conductor sufficient room to enter bore  142  and allow hollow prong  152  to enter between center conductor  124  and insulation layer  125 . After the insulated conductor is correctly positioned within bore  142 , threading of the cap  154  onto the housing  141  can cause the clamping arms  153  to clamp the electrical conductor  123 . This can help to hold the electrical connector and insulated electrical conductor together. 
     In a preferred embodiment, a cap can be placed over clamping arms  153  to hold them to insulation layer  125 . In the embodiment shown in FIGS. 15 and 16 closure cap  154  has an open end  155  for passing the electrical conductor  123  therethrough and has internal threads  156  within passageway  157  for attaching to threads  144  of housing  141 . The inside annular surface  158  may be angled for wedging against an angled surface  160  on the extending arms  153  for clamping the arms to the insulation  125 . In an alternative embodiment, cap  154  and housing  141  can be configured for a snap fit, without the need for threads  144  or  156 . 
     A further embodiment of the invention which incorporates the clamping arms of FIG. 10 in the connector of FIG. 15 is shown in FIG.  17 . Specifically, the housing  141  is modified to substitute clamping arms  161 , including engaging tips  162  similar to those shown in FIG. 10, for the clamping arms  153  of FIG.  15 . In this arrangement when the conductor  123  is entered by the hollow prong  146  and fully positioned in the housing  141 , the clamping arms  151  can be mechanically clamped on to the insulating layer  125  of the conductor  123 . In the arrangement illustrated, the engaging tips  162  are selected so as to engage only the insulating layer  125  and not the center conductor  124 , thereby to avoid unwanted electrical conduction from the center conductor  124 . Thereafter the cap  154  is placed over the clamping arms  161  and secured to the housing  141 , holding the conductor  123  in an irremovable position unitary with the housing  141 . Circumstances might arise where it is desired that the engaging tips  162  pierce the insulating layer  125  and engage the center conductor  124  in order to support electrical conduction with the hollow prong  146 . In that case the housing can provide a conductive path between the clamping arm  161  and the hollow prong  146  and insulating shielding can be provided for preventing the housing from being electrically shorted. 
     Again, once insulated conductor  123  is engaged with connector  140 , there are a variety of designs which can be used to engage connector  140  with external apparatus to create electrical contact between conductor  124  and the external apparatus. For example, prong  147  can be the same diameter as conductor  124  or can smaller or larger, as desired. Other designs would be readily apparent to a person skilled in the art having the benefit of the subject disclosure. 
     The method of the present invention involves coupling an electrical connector in accordance with the subject invention to an insulated electrical conductor. Examples of such electrical connectors are shown in FIGS. 11-14 and FIGS. 15 and 16. The end of an insulated electrical conductor  123  is guided to the connector housing such that the hollow portion of the center prong squeezes between the center conductor and insulation layer  125 . Accordingly, center conductor  124  makes electrical contact with prong  120  or  122 . With respect to a coaxial cable, clamping arms  113  can then be pushed onto insulation layer  129  to drive the gripping tips  133  into the insulation to make electrical contact with conductor  127 . With respect to an insulated conductor having a single conductor, arms  153  in FIGS. 15 and 16, can be pushed onto the insulation for holding the electrical conductor to the connector. The connectors shown in FIGS. 11-16 can, for example, be manually clamped with a person&#39;s fingers, clamped with a clamping tool such as pliers, and/or clamped via a closure cap for pressing arms  153  to the insulation. A closure cap  154  can also be used to drive the clamping arms  153  against the insulation, as shown in FIGS. 15 and 16. Such a closure cap  154  can be designed to fit over tips  133  after tips  133  have been clamped such that cap  154  can push tips  133  a bit further into the insulation and then hold tips  133  in such position. 
     Referring to FIGS. 18 and 19, an embodiment of the subject invention is shown which utilizes the inner conductor of a coaxial cable to make electrical contact between the coaxial cable, having the subject electrical connector connected, and other connectors or insulated electrical conductors. The coaxial cable can be stripped such that the end of the cable is flush with the exception of the protruding inner conductor. The coaxial cable can then be inserted into the subject connector such that the protruding inner conductor passes through an aperture in insulating base  121  and into bore  117 . The clamping arms  113  can then be positioned such that electrical contact with conductive sheath  127  is made. If desired, an appropriate means to secure the clamping arms  113  in place can be used to ensure electrical contact with the conductive sheath  127  is maintained. In addition, if desired, a portion of conductive sheath  127  and outer insulation layer  129  can be stripped, and the aperture in base  121  can be enlarged, such that insulation layer  125  can also pass into the aperture in base  121 . In this embodiment, base  121  can be conducting. For example, base  121  can be an extension of the housing, such that insulation layer  125  functions to insulate the inner conductor of the coaxial cable from the housing. 
     A hollow segmented center conductive prong in accordance with the subject invention can advantageously provide an improved connection between a connector and an insulated conductor and can accommodate different types and sizes of conductors. In particular, a hollow segmented center prong can enhance the contact made with a solid center conductor. However, the present invention should not be construed as limited to the forms shown which are to be considered illustrative rather than restrictive. 
     It should be understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and the scope of the appended claims.