Patent Publication Number: US-8535092-B2

Title: Mini-coax cable connector

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 12/685,606, filed Jan. 11, 2010, which is a continuation-in-part of U.S. application Ser. No. 11/895,367, filed Aug. 24, 2007, now U.S. Pat. No. 7,645,161, which is a continuation-in-part of U.S. application Ser. No. 11/716,488, filed Mar. 9, 2007, which is a continuation-in-part of U.S. application Ser. No. 10/927,884, filed Aug. 27, 2004, now U.S. Pat. No. 7,188,507. All of these applications are incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     The following relates to coaxial cable connectors and more particularly relates to a novel and improved mini-coaxial cable connector assembly which is conformable for use with different size cables in effecting positive engagement with a connector assembly in connecting the cable to a post or terminal. 
     The problems associated with the connection of mini-coaxial cables as well as larger size cables to a post or terminal in the field are discussed at some length in hereinabove referred to co-pending application for patent for MINI-COAXIAL CABLE CONNECTOR and in U.S. Pat. No. 6,352,448 for CABLE TV END CONNECTOR STARTER GUIDE. This invention is directed to further improvements in termination assemblies to be employed for mini-coaxial cables in which the termination assembly is characterized in particular by being comprised of a minimum number of preassembled parts which can be quickly assembled at the manufacturing site as well as in the field and is readily conformable for connection of different sized mini-coaxial cables to BNC and RCA connectors. Further wherein an extension tip can be recessed to permit a conductor to be positioned toward the back of the connector assembly, such as, for example, RCA connector assemblies; and including a novel form of centering guide for guiding the conductor into the recessed end of the extension tip. 
     SUMMARY 
     In one aspect it is desirable to eliminate any form of a coupling or adaptor sleeve for small diameter coaxial cables so that the cable can be installed directly into the end of an extension tip which has been preassembled within the connector body. 
     In another aspect the connector body is provided with the necessary adaptability for connection to different sized cables and in such a way as to assure accurate alignment between the cable and connector preliminary to crimping of the connector onto the cable and prevents shorting between the cable layers with one another as well as with conductive portions of the connector; and specifically wherein inner and outer concentric compression members in the crimping region of the connector body cooperate in effecting positive engagement with the cable. 
     The foregoing is achieved by direct connection of the exposed end of a coaxial cable to an extension tip either prior to or after mounting of the extension tip in a hollow connector body wherein the cable is of the type having inner and outer concentric electrical conductors, an annular dielectric separating the conductors and an outer jacket of electrically non-conductive material, the inner and outer conductors being exposed at the end and the inner conductor projecting beyond the dielectric at one end of the cable; and the connector body is characterized by having a slotted compression ring which cooperates with an inner slotted sleeve to effect positive engagement with the cable in response to radially inward compression. The inner sleeve and compression ring are dimensioned to undergo the necessary compression in response to axial advancement of a crimping ring, and the trailing end of the inner sleeve is slotted to form prong-like segments having internal and external teeth so that the trailing end of the sleeve can be compressed into engagement with the cable without crushing the dielectric layer. 
     A spring-like retainer clip within a bore at one end of the extension tip is adapted to grasp the conductor pin and connect to the tip, and the retainer clip can be varied in size for different diameter conductor pins. Elimination of the adaptor sleeve on the cable affords greater latitude in visualization of the color of the extension tip as well as the compression ring; and either or both may be color-coded to match up with different sized cables. 
     It is therefore to be understood that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed and reasonable equivalents thereof. 
     The above and other objects, advantages and features of the present invention will become more readily appreciated and understood from a consideration of the following detailed description of preferred and modified forms of the present invention when taken together with the accompanying drawings in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded, longitudinal sectional view of one embodiment comprised of the standard mini-coaxial cable prior to insertion into a connector assembly having a modified pre-assembled extension tip; 
         FIG. 2  is a longitudinal sectional view of the one embodiment of  FIG. 1  with the mini-coaxial cable inserted into the modified extension tip prior to a crimping operation; 
         FIG. 3  is another longitudinal sectional view of the one embodiment illustrating advancement of the extension tip and cable through the connector assembly prior to the crimping operation; 
         FIG. 4  is an enlarged longitudinal sectional view of the one embodiment following the crimping operation; 
         FIG. 5  is an end view of the one embodiment illustrated from the entrance end of the cable; 
         FIG. 6  is an end view of the opposite end of the one embodiment to that shown in  FIG. 5 ; 
         FIG. 7  is an exploded view of the parts comprising the coaxial cable and modified extension tip prior to assembly; 
         FIG. 8  is an exploded view of the parts comprising the modified extension tip and connector body prior to assembly; 
         FIG. 9  is a longitudinal sectional view of a second embodiment illustrating a BNC connector assembly and illustrating a mini-coaxial cable inserted into the pre-assembled modified extension tip; 
         FIG. 10  is another longitudinal sectional view of the embodiment shown in  FIG. 9  after advancement of the cable and extension tip through the connector assembly but prior to the crimping operation; 
         FIG. 11  is an enlarged longitudinal sectional view of the second embodiment shown in  FIGS. 9 and 10  following the crimping operation; 
         FIG. 12  is an end view taken from the entrance end of the cable in  FIG. 11 ; 
         FIG. 13  is an end view taken from the opposite end of  FIG. 11  to that of  FIG. 12 ; 
         FIG. 14  is a somewhat fragmentary, longitudinal sectional view of a compression tool utilized in combination with another embodiment of a connector assembly; 
         FIG. 15  is a sectional view in more detail of the connector assembly shown in  FIG. 14 ; 
         FIG. 16  is a sectional view of the end of another form of connector assembly utilized with mini-coaxial cable connectors; 
         FIG. 17  is a longitudinal sectional view of the embodiment shown in  FIGS. 14 and 15  after the crimping operation; 
         FIG. 18  is a longitudinal sectional view of still another embodiment with the parts assembled prior to advancement through the connector assembly; 
         FIG. 19  is another sectional view corresponding to that of  FIG. 18  with the coaxial cable and extension tip fully inserted into the connector assembly; and 
         FIG. 20  is a longitudinal sectional view of the embodiment shown in  FIGS. 18 and 19  following the crimping operation;. 
     
    
    
     DETAILED DESCRIPTION OF ONE EMBODIMENT 
     Referring in more detail to the drawings, there is illustrated in  FIGS. 1 to 8  one embodiment which is comprised of a standard mini-coaxial cable C, a hollow connector body  10  having inner and outer concentric sleeves  11  and  12 , and a plastic compression ring  13 . A crimping ring assembly  14  is preassembled at one end of the body  10 , and a modified extension tip  16 ′ is preassembled at the opposite end of the body  10  to the crimping ring assembly  14 . 
     As a setting for the embodiments to be described, the cable C is made up of an inner conductor pin or wire  20  which is surrounded by a dielectric insulator  22  of electrically non-conductive material, such as, a rubber or rubber-like material, a braided conductor layer  24 , and an outer jacket  26  of an electrically non-conductive material, such as, a rubber or rubber-like material. The end of the cable C is further prepared for assembly by removing a limited length of the jacket  26  and braided conductor  24  as well as the insulated layer  22  in order to expose an end of the pin  20  along with a foil layer surrounding the pin  20 . The braided conductor layer  24  is peeled away from the insulator  22  and doubled over as at  24 ′ to cover the leading end of the jacket  26 . 
     As shown in  FIGS. 1 to 8 , the sleeve  11  has a thin-walled, annular trailing end  28  and sealing rings or ribs  29  along its inner surface in facing relation to the jacket  26 , and the body  10  terminates in an annular shoulder  30  at one end having an annular end flange  32  in abutting relation to an insulator guide  33 . The sleeve  11  is dimensioned such that the trailing end  28  will extend over the end of the doubled-over layer  24 ′ when the pin  20  is inserted into the end of the extension tip  16  in a manner to be described in more detail. For this purpose, the layer  22  is exposed for a length corresponding to the length of the wall portion  28  of the sleeve  11  when assembled in the relationship shown in  FIG. 4 . The outer sleeve  12  has a thin-walled trailing end  34  aligned in outer spaced concentric relation to the end  28  to form an annular space therebetween for insertion of the compression ring  13 , and the trailing end  34  is raised slightly from the outer surface of the sleeve  12  to form a shoulder  27  at one end to receive the offset end  15  of the crimping ring  14 . The inner surface of the trailing end  34  is provided with a series of sealing ribs or rings  35  to engage the outer surface of the compression ring  13 . The sleeve  12  terminates at its opposite end in a thickened annular end portion  40 , including a radially inner wall surface flush with the external wall surface of the end flange  32 , and a radially outwardly extending shoulder  39  is interposed between one end of the crimping ring assembly  14  and a reinforcing band  42  on the outside of the connector body  10 . 
     As best seen from the exploded view of  FIG. 8 , the trailing end  28  of the inner sleeve  11  is provided with circumferentially spaced longitudinal slots  44  of a length substantially corresponding to the slotted end of the compression ring  13  to be described, the slots each being of a width to control the inward degree of bending by the crimping ring assembly  14 . Similarly, the compression ring  13  has a solid or continuous annular end  46  and circumferentially spaced longitudinal slots  48  extending from the end  46  for the greater length of the ring  13  toward its trailing end and dividing the ring  13  into a series of elongated annular segments, the slots  48  each being of a width to control the degree of inward bending when compressed by the crimping assembly  14 . Further, the compression ring  13  is composed of a plastic material of limited flexibility and dimensioned to be of a thickness to assure positive engagement of the inner sleeve  11  with the cable C when the extension tip  16 ′ is inserted into the body  10 . Again, it is important to dimension the width of the slots  48  to limit the amount of contraction of the ring  13  so that the sealing ribs  29  will compress the jacket  26  enough to prevent pull-out but not enough to crush the dielectric layer  22 . This is especially important in cables operating at higher frequencies in which any bending or crushing of the dielectric can create an impedance that downgrades the signal and prevents return losses. As further seen from  FIG. 3 , the prepared cable C is inserted into the tip  16 ′ and advanced through the body  10  until the slotted segments of the inner sleeve  11  are positioned over the doubled-over layer  24 ′ and jacket  26 . 
     The opposite end of the body  10  is made up of a ferrule  50  which is slotted as at  52  into spring-like annular segments  54  extending from an annular base portion  56  of the ferrule  50  to facilitate attachment to a post or terminal, not shown, and the base  56  forms a central opening or passage for advancement of the tip  16  beyond the end of the ferrule, as shown in  FIG. 3 . The base  56  has a rearward extension or keeper  60  of annular configuration between the band  42  and the guide  33  as well as the flange  39  on the inner sleeve. Thus, the inner walls of the sleeve  11  and guide  33  define the inner wall surface of the body  10 , and the guide  33  is provided with an internal shoulder  63  to limit advancement of the extension tip  16  through the body  10 . 
     The modified extension tip  16 ′ and cable C are illustrated in exploded form in  FIG. 1 , the tip  16 ′ being shown inserted into the connector body  10  and comprises an elongated cylindrical metal body  66 ′ terminating in a recessed end  68 ′ for press-fit engagement with a supplementary plastic extension rod  69 ; and an elongated central bore or recess  70 ′ extends through the opposite end for a limited length of the tip  16 ′. The extension rod  69  is of a diameter corresponding to the tip  16 ′ with a projecting end  71  of reduced diameter for press-fit engagement with the recessed end  68 ′. When the extension rod is inserted into the connector body and advanced through the centering guide  33  as shown in  FIGS. 1-3 , the extension tip  16 ′ will project to a position close to or flush with the end of the crimping ring assembly  14 . An annular insulator cap  72 ′ is mounted on the opposite end of the tip  16 ′ in surrounding relation to the entrance to the bore  70  and supports the end of an elongated spring  74 ′ extending through the bore and offset from the wall slightly to bear against the conductor pin  20 . The end of the cap  72 ′ is beveled as at  73 ′ to wedge against the dielectric layer  22  surrounding the pin  20  and which is peeled away from the pin  20  into the outer layer  24 ′ as earlier described. 
     The crimping ring assembly  14  is of a type that can be preassembled onto the connector body  10  and axially advanced over the sleeve  12  to force it into crimping engagement with the slotted end  44  of the compression ring  13 . To this end, the crimping ring  14  is made up of an annular body  80  composed of a low-friction material having limited compressibility, such as, DELRIN.RTM. or other hardened plastic material. The body has a straight cylindrical portion  82  and a forwardly tapered portion  84  which terminates in a leading end  83  having an internal shoulder or rib  85 . The leading end  83  fits over the trailing end of the sleeve  12  so that the crimping ring  14  can be axially advanced over the end of the sleeve  12  until the internal shoulder or rib  85  advances past the raised end  34 , as shown in  FIG. 4 , to preassemble the ring  14  onto the connector  10 . 
     An exterior surface of the body  80  is recessed or undercut to receive a reinforcing liner  92  which is preferably composed of brass and which fits snugly over the body  80 . The leading end  93  of the liner  92  projects outwardly beyond the external surface of the body  80  to define an external shoulder of a diameter slightly greater than that of the leading end  83 , as best seen from  FIG. 4 . 
     The extension tip  16 ′ is inserted into the connector body  10  until the end of the extension rod  69  opposite to the reduced end  79  is positioned in alignment with the centering guide  33 , as shown in  FIG. 1 , so that the entrance to the bore  70 ′ is at or in close proximity to the entrance to the crimping ring assembly  14  to thereby facilitate insertion of the conductor pin  20  into the beveled end  73 ′ of the bore  70 ′. The crimping ring assembly  14  is preassembled onto the sleeve  12 , as described earlier. Typically, the extension tip  16 ′ and crimping ring  14  are preassembled in the manner just described prior to shipment to the field so that the color coding of the elements is followed to signify the desired cable size and application of the connector assembly to the installer. Although not illustrated in  FIGS. 2 and 3 , when the cable is advanced to the intermediate position shown in  FIG. 2 , the extension rod  69  can be removed or permitted to drop off the end of the extension tip  16 ′. A standard crimping tool, not shown, may be employed to axially advance the crimping ring  14  over the sleeve  12  until the leading end or rib  85  moves into snap-fit engagement with the groove  41  and abuts the shoulder  40 . The tapered surface  84  will cause the end portion  34  of the sleeve  12  to radially contract and force the compression ring  13  into positive engagement with the inner sleeve  11  and in turn cause the rings  29  on the segments to be crimped into positive engagement with the jacket  26  as well as the doubled-over portion  24 ′. One such crimping tool is disclosed in U.S. Pat. No. 6,089,913 and is incorporated by reference herein. The cooperation between the ribs  34  when forced into the compression ring  13  and in turn forcing the internal teeth  29  into engagement with the layer  24 ′ as well as the jacket  26  increases the pull-out strength of the termination assembly both with respect to the end of the cable C and the connector  10 . 
     Detailed Description of a Second Embodiment with Crimping Ring Assembly 
       FIGS. 9 to 13  illustrate a modified form of connector assembly  10 ′ for a BNC connector or fitting of increased length compared to the RCA connector shown in  FIGS. 1 to 8  and having an elongated barrel  96  with a bayonet slot  98  connected to a ferrule  100  Inner and outer spaced connector sleeves  11  and  12  and compression ring  13  along with the crimping ring assembly correspond to those of  FIGS. 1 to 8  and are correspondingly enumerated along with the cable C. Owing to the increased length of the fitting, the extension tip  16  is replaced by an insert socket  102  having a hollow nose  103  of reduced diameter which is slidably disposed within the inner sleeve  11 , and an extension pin  104  is disposed on the exposed end of the conductor pin  22  of the cable C. Initially, as shown in  FIG. 9 , the pin  104  will guide the cable C into engagement with the socket  102 . Continued advancement of the cable C will cause the pin  104  to carry the socket  102  into alignment with a beveled opening  106  in a stationary block  108  at the end of the ferrule  100  and until the pin  104  reaches the end of the ferrule  100 , as shown in  FIG. 10 . In a manner corresponding to  FIGS. 1 to 8 , forward advancement of the crimping ring assembly  14  will crimp the inner sleeve  11  into positive engagement with the cable jacket  26 , as illustrated in  FIGS. 11 to 13 ; and as best illustrated in the end view of  FIG. 12 , the compression ring  13  can be dyed a specific color representing the size of cable C which will best fit and provide optimum crimping engagement with the connector body  10 . 
     Detailed Description of First and Second Embodiments with Compression Tool 
       FIG. 14  illustrates a compression tool T in place of a crimping ring assembly  14  previously described for crimping an RCA connector similar to that of  FIGS. 1 to 8  and in which like parts of the cable C and connector body  10  are correspondingly enumerated. The principal modification is the utilization of an outer sleeve  12 ′ having a convex raised surface portion  110 . The cable C is inserted into the tip extender  16  so as to be anchored in chuck  112  and centered in relation to the dies  114 ,  115  as the dies  114 ,  115  are advanced into crimping engagement with the outer sleeve  12 ′. Again, and as shown in  FIGS. 15 and 16 , the connector body  10 ′ includes an annular plastic insert  13 ′ in the space between the inner and outer concentric sleeves  11 ′ and  12 ′ for the mini-coaxial cable represented at C, and the outer jacket  26  and braided insulator  24  are positively engaged by the inner sleeve  11 ′ when the outer sleeve  12 ′ and ring  13 ′ are compressed radially inwardly by the compression tool T, as shown in  FIG. 17 . 
       FIGS. 18 to 20  illustrate the manner in which the BNC connector of  FIGS. 9 to 13  can be crimped by the compression tool T and specifically wherein the ferrule  100  is inserted between the spring clips  113  prior to compression of the sleeves  11 ′,  12 ′ and the compression ring  13 ′ by the compression die members  114  and  115 . 
     Mini-coaxial cables are particularly useful in cellular telephones, security cameras and other applications where there are decided space limitations or where short runs of cable are used. Referring to the embodiments shown and described, it will be evident that the thickness of the compression ring  13 , as well as the width of the slots  44  and  48  may be varied according to the size or diameter of the cable C and be proportioned according to the space allowance between the cable C and the connector sleeve  11 . Further, the compression ring may be installed either before or after shipment to the field. For example, it may be desirable for the installer to select a particular size of compression ring which would be dyed or colored to match a particular cable size. To that end, the compression ring  13  should have sufficient elasticity or spreadability to be inserted axially into the annular space between the assembled sleeves  11  and  12 . 
     The resilient band  42  shown in  FIG. 2 , may be inserted into the groove formed between the ferrule  50  and the shoulder  40  after the connector has been crimped together into the closed position. The band  42  is manually stretchable over the end of the ferrule  50  and, when released, will contract into the groove as described. The band  42  also may be one of several different colors to signify the intended application of the connector to a particular use. In addition, the compression ring  13  as well as the guides  33  and  72  may be of different selected colors which represent the size of cable C for which the connector body  14  is designed. The cap is visible to the installer when inserting the cable C into the tip  16  prior to the crimping operation, and both the guide  33  and ring  13  are visible from either end of the connector body  10 , as shown in  FIGS. 5 ,  6  and  12 ,  13  after the crimping operation. 
     It is therefore to be understood that while different embodiments are herein set forth and described, the above and other modifications may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and reasonable equivalents thereof.