Patent Publication Number: US-10777915-B1

Title: Coaxial cable connector with a frangible inner barrel

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/717,826, filed Aug. 11, 2018, which is hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to electrical apparatus, and more particularly to coaxial cable connectors. 
     BACKGROUND OF THE INVENTION 
     Coaxial cables transmit radio frequency (“RF”) signals between transmitters and receivers and are used to interconnect televisions, cable boxes, DVD players, satellite receivers, modems, and other electrical devices and electronic components. Typical coaxial cables include an inner conductor surrounded by a flexible dielectric insulator, a foil layer, a conductive metallic tubular sheath or shield, and a polyvinyl chloride jacket. The RF signal is transmitted through the inner conductor. The conductive tubular shield provides a ground and inhibits electrical and magnetic interference with the RF signal in the inner conductor. 
     Coaxial cables must be terminated with cable connectors to be coupled to mating posts of electrical devices. Connectors typically have a connector body or barrel, a threaded fitting mounted for rotation on an end of the barrel, a bore extending into the barrel from an opposed end to receive the coaxial cable, and an inner post within the bore coupled in electrical communication with the fitting. Generally, connectors are crimped onto a prepared end of a coaxial cable to secure the connector to the coaxial cable. Crimping usually requires a special tool. 
     When some connectors are crimped, whether by design flaw or installation flaw, gaps, holes, or pinch or pressure points can be created between the crimped or compressed connector barrel and the cable within. This can lead to RF performance issues caused by RF egress, RF ingress, and potentially unreliable grounding. It can also make the connector vulnerable to moisture intrusion, which leads to corrosion, signal degradation, and other issues. An improved connector is needed. 
     SUMMARY OF THE INVENTION 
     An embodiment of a coaxial cable connector includes an inner post and a coupling interface mounted on the inner post, a barrel mounted on the inner post, the barrel including a front sleeve and a rear sleeve coupled to each other at a frangible band, and a compression collar mounted over the barrel for movement between a retracted position and an advanced position. Movement of the compression collar from the retracted position to the advanced position severs the frangible band, thereby separating the front sleeve from the rear sleeve. 
     Another embodiment of a coaxial cable connector includes an inner post, a barrel mounted on the inner post, the barrel including front sleeve, a middle sleeve, and a rear sleeve, each formed integrally as part of the barrel, and a compression collar mounted over the barrel for movement between a retracted position and an advanced position. The middle sleeve separates from each of the front and rear sleeves when the compression collar moves from the retracted position to the advanced position thereof. 
     The above provides the reader with a very brief summary of some embodiments discussed below. Simplifications and omissions are made, and the summary is not intended to limit or define in any way the scope of the invention or key aspects thereof. Rather, this brief summary merely introduces the reader to some aspects of the invention in preparation for the detailed description that follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring to the drawings: 
         FIG. 1  is a side elevation view of a coaxial cable connector with a frangible inner barrel; 
         FIGS. 2A-2C  are section views take along the line  2 - 2  in  FIG. 1 , showing the connector of  FIG. 1  moving from an uncompressed condition to a compressed condition; 
         FIGS. 3A-3C  are section views take along the line  2 - 2  in  FIG. 1 , showing the connector of  FIG. 1 , applied with a cable, moving from the uncompressed condition to the compressed condition; 
         FIG. 4  is a side elevation view of a coaxial cable connector with a frangible inner barrel; 
         FIGS. 5A-5C  are section views take along the line  5 - 5  in  FIG. 4 , showing the connector of  FIG. 4  moving from an uncompressed condition to a compressed condition; and 
         FIGS. 6A-6C  are section views take along the line  5 - 5  in  FIG. 4 , showing the connector of  FIG. 4 , applied with a cable, moving from the uncompressed condition to the compressed condition. 
     
    
    
     DETAILED DESCRIPTION 
     Reference now is made to the drawings, in which the same reference characters are used throughout the different figures to designate the same elements.  FIG. 1  is an elevation view of a coaxial cable connector  10  with a frangible inner barrel (hereinafter, “connector  10 ”), and  FIG. 2A  is a section view bisecting the connector  10  along the line  2 - 2  in  FIG. 1 . The connector  10  includes a body or barrel  11 , a coupling nut  12  mounted for rotation on the barrel  11 , a compression collar  13  mounted to the barrel  11  for axial movement between retracted and advanced positions with respect to the barrel  11 , and an inner post  14 , on which both the barrel  11  and the coupling nut  12  are mounted. A longitudinal axis A extends through the center of the connector  10 , generally defining an axis of rotational symmetry for the connector  10 . 
     The inner post  14  is an elongate sleeve extending along the longitudinal axis A and having rotational symmetry thereabout. The inner post  14  includes opposed front and rear ends  20  and  21 , a sidewall  22  extending therebetween, and opposed inner and outer surfaces  23  and  24 . The outer surface  24  at the rear end  21  of the inner post  14  is formed with two annular barbs or ridges  25  and  26  projecting toward the front end  20  and radially outward from the longitudinal axis A. The ridges  25  and  26  are laterally or axially spaced apart from each other along the rear end  21  of the inner post  14 . The ridges  25  and  26  provide grip on a cable applied to the connector  10  to resist withdrawal of the cable from the connector  10 , and also provide an increased diameter on the inner post  14  over which the cable must be passed. In some embodiments, the inner post  14  may have other designs or structures, such as a shortened axial length. 
     The coupling nut  12  is mounted for rotation at the front end  20  of the inner post  14 . The coupling nut  12  is a sleeve having opposed front and rear ends  30  and  31 , an integrally-formed ring portion  32  proximate to the front end  30 , and an integrally-formed nut portion  33  proximate to the rear end  31 . The ring portion  32  has a smooth annular outer surface and an opposed inner surface which may be smooth, threaded, ribbed, or otherwise configured for engaging with a female RF mating post of an electronic component. The nut portion  33  of the coupling nut  12  has a hexagonal outer surface to receive the jaws of a tool. The coupling nut  12  is constructed of a material or combination of materials having strong, hard, rigid, durable, and high electrically-conductive material characteristics, such as metal. A gasket  34  disposed between the inner post  14  and the coupling nut  12  is constructed of a deformable yet resilient material, such as rubber, which prevents the intrusion of moisture into the connector  10 , and maintains a snug fit between the coupling nut  12  and the inner post  14 . In this way, a permanent, low-friction connection is established that allows the coupling nut  12  to rotate freely upon the inner post  14  about the axis A while still maintaining the coupling nut  12  and the inner post  14  in permanent electrical communication. In some embodiments, the gasket  34  may be omitted, and so the gasket  34  is not shown in other drawings of the connector  10 . Moreover, in some embodiments of the connector  10 , the coupling nut  12  may have another design, such as press- or push-on design, collet design, or other design which involves different structure. As such, the coupling nut  12  can be considered a “coupling interface.” 
     The construction, structure, and arrangement of the coupling nut  12  and the inner post  14  are not critical features of this connector  10 , and are shown and described here and in the drawings to provide context for the connector  10 . It is noted that any suitable coupling nut and inner post may be used in the spirit of the discussion herein. The discussion now turns to the barrel  11 , the compression collar  13  mounted over the barrel  11 , and how those two elements are constructed, arranged, and operated within the connector  10 . 
     Referring primarily to  FIG. 2A , the barrel  11  is an elongate, cylindrical sleeve extending along the longitudinal axis A with rotational symmetry thereabout, and is constructed of a material or combination of materials having strong, rigid, size memory, and shape-memory material characteristics, as well as a low coefficient of friction, such as plastic, metal, or the like. The barrel  11  receives and securely holds a cable introduced to the connector  10 . 
     The barrel  11  has opposed front and rear ends  40  and  41  with a cylindrical sidewall  42  extending therebetween, which sidewall  42  has opposed inner and outer surfaces  43  and  44 . The inner surface  43  defines and bounds a cable-receiving interior space shaped and sized to receive the coaxial cable, and in which the rear end  21  of the inner post  14  is disposed. An opening at the rear end  41  of the barrel  11  communicates with this cable-receiving interior space. 
     A front flange  45  is at the front end  40  of the barrel  11 . The front flange  45  is a large, inwardly-turned annular lip which abuts and is seated on the outer surface  24  of the inner post  14  behind its front end  20 . It is a constriction mount on the inner post  14 ; the front flange  45  is seated and secured on the outer surface  24  with a friction fit, thereby securing the barrel  11  on the inner post  14 . 
     The sidewall  42  of the barrel  11  extends rearwardly from the front flange  45 , and the front flange  45  has a smaller inner diameter than any part of the sidewall  42  behind the front flange  45 . Briefly, some terms are used with respect to the embodiment of the connector  10  to refer to direction or location. “Rearwardly,” “behind,” and similar terms indicate that something extends, is directed, or is located proximate to or toward the rear end  41  of the barrel  11 . Conversely, “forwardly,” “ahead,” and similar terms indicate that something extends, is directed, or is located proximate to or toward the front end  30  of the coupling nut  12 . 
     The barrel  11  is constructed from a front sleeve  50  and a rear sleeve  51  which are integrally and monolithically formed to each other at an annular, frangible band  52 . The forward and rear sleeves  50  and  51  are frangible with respect to each other; they are designed to separate from each other while still encased within the compression collar  13  to grasp and secure a cable applied to the connector  10 . Explained in more detail below and only introduced here, when the compression collar  13  advances forward, the rear sleeve  51  separates from the front sleeve  50  and then slides over it, causing the front sleeve  50  to deform inwardly. The barrel  11  is constructed to cause this separation in response to axial compression of the connector  10 . The front sleeve  50  then captures the applied cable. 
     Still referring to  FIG. 2A , the rear sleeve  51  is a short, cylindrical collar or cuff. The rear sleeve  51  includes the rear end  41  and the sidewall  42  of the barrel  11 . From the rear end  41 , the rear sleeve  51  extends forwardly to the frangible band  52 . A flat or blunt front face  53  projects radially outward from the frangible band  52 . The front face  53  is roughly perpendicular to the axis A and defines the forward termination of the rear sleeve  51 . The front face  53  has a height, from the frangible band  52  to the outer surface  24 , which is approximately half the thickness of the sidewall  42  between the inner and outer surfaces  43  and  44  just in front of the rear face  54 . The rear sleeve  51  is substantially rigid and maintains its shape and size during movement and arrangement of the connector  10 . In this way, the rear sleeve  51  moves with the compression collar  13 , in which it is encased, when the connector  10  is secured on the cable. 
     In front of the rear sleeve  51 , the front sleeve  50  is a cylindrical collar or cuff, is longer than the rear sleeve  51 , and includes the front end  40  of the barrel  11  and the sidewall  42  extending rearwardly therefrom to an oblique rear face  54 . Indeed, the front sleeve  50  extends from the front end  40  to the frangible band  52 , because the frangible band  52  is formed between the front face  53  and the rear face  54 . The oblique rear face  54  is oriented radially inward and axially rearward, such that the rear face  54  presents radially outward and axially rearward. In this way, the rear face  54  is an annular ramp over which the rear sleeve  51  is driven when the connector  10  is compressed, as will be discussed. The rear face  54  of the front sleeve  50  terminates rearwardly between the two axially-spaced apart ridges  25  and  26 ; thus, the rear end of the front sleeve  50  is directly across from a location between the two ridges  25  and  26 . 
     The front sleeve  50  further includes the front flange  45  and an annular channel  60 , just behind the front flange  45 , recessed into the sidewall  22  from the outer surface  24 . Proximate to and just behind the channel  60 , and cooperating with the front flange  45  to bound the channel  60  is a forward barb or ridge  61  which rises radially outward, such that when the compression collar  13  is advanced axially over it, the compression collar  13  biases the ridge  61  radially inwardly slightly. Behind the ridge  61 , the outer diameter of the sidewall  22  decreases slightly until it enlarges at a shoulder  62 . The shoulder  62  is a forwardly-directed annular ridge defining an enlarged outer diameter of the sidewall  22 . Then, from the shoulder  62  rearward, the front sleeve  50  has a constant outer diameter until the oblique rear face  54  near its rear end. As discussed above, the rear face  54  converges or tapers radially inwardly as it extends rearwardly. The rear face  54  tapers down to the frangible band  52 . 
     The front sleeve  50  terminates rearwardly at the rear face  54 , but is joined to the rear sleeve  51  at the frangible band  52 . The frangible band  52  is the union between the front sleeve  50  and the rear sleeve  51 . Initially, before the connector  10  is compressed, the barrel  11  is preferably a single, integral, monolithic piece and the front sleeve  50  and the rear sleeve  51  are constituent elements of that piece. The frangible band  52  joins the front sleeve  50  to the rear sleeve  51 ; it is an axially-narrow, radially-thinned portion of the sidewall  42  of the barrel  11  formed between the rear face  54  of the front sleeve  50  and the front face  53  of the rear sleeve  51 . The frangible band  52  is preferably a thinned portion of the sidewall  42  which is continuous and annular and formed entirely to each of the rear face  54  and the front face  53 . In alternate embodiments, however, the frangible band  52  has another structure, such as a series of small, circumferentially-separated fingers of the sidewall  42  formed between the two faces  53  and  54 , or some other structure. 
     The frangible band  52  is radially encircled by the front face  53  of the rear sleeve  51 , which front face  53  projects radially outward from the frangible band  52 . The frangible band  52  is radially closer to the axis A than is the front face  53 . Moreover, the rear face  54  of the front sleeve  50  rises obliquely away from the frangible band  52 . Thus, a V-shaped annular notch  64  is defined above—or just radially outside of—the frangible band  52 , encircling the band  52 . The notch  64  is bound by the frangible band  52 , the rear face  54 , and the compression collar  13 . 
     With continuing reference to  FIG. 2A , the compression collar  13  is mounted for reciprocal axial movement over the barrel  11 . It includes opposed front and rear ends  70  and  71 , an annular sidewall  72  extending between the front and rear ends  70  and  71 , and opposed inner and outer surfaces  73  and  74 . An interior space bound by the inner surface  73  extends into the compression collar  13  from an opening formed at the rear end of the compression collar  13 . The interior space is a cylindrical bore and is sized to receive the barrel  11  with the coaxial cable carried within. The compression collar  13  is fit onto the rear end  41  of the barrel  11  so as to limit the relative radial and rotational movement of the compression collar  13  on the barrel  11  with respect to the axis A. The compression collar  13  is constructed of a material or combination of materials having strong, hard, rigid, resilient, and durable material characteristics, such as metal, plastic, or the like. The compression collar  13  does not deform in response to movement between its retracted and advanced positions, or in response to deformation, movement, or other change of the barrel  11  within. 
     The compression collar  13  has a constant outer diameter from the front end  70  to just in front of the rear end  71 . Most of the length of the sidewall  72  has one of two inner diameters; a larger inner diameter proximate the front end  70  (and resulting in a thinner sidewall  72  there) and a smaller inner diameter proximate the rear end  71  (and resulting in a thicker sidewall  72  there). At the rear end  71 , the sidewall  72  has an inwardly-directed lip  77 . The lip  77  has a reduced inner diameter relative the rest of the compression collar  13 , and relative the smaller inner diameter proximate the rear end  71 . Indeed, the inner diameter of the lip  77  is even smaller than the inner diameter of the barrel  11  at its rear end  41 , such that it hangs over the rear end  41  of the barrel  11 . The lip  77  serves as a stop against the barrel  11 , so that, when the compression collar  13  is moved forward, the lip  77  contacts the rear end  41  of the barrel  11  and pushes the rear end  41  forward along the axis A, thereby urging deformation of the barrel  11 . 
     The inner diameter of the compression collar  13  is constant from the lip  77  forward, until an oblique face  75  approximately halfway along the length of the compression collar  13 . The oblique face  75  extends into the sidewall  72 , reducing its inner diameter. The oblique face  75  is an annular expansion of the inner surface  73  of the compression collar  13 , extending radially into the sidewall  72  from the inner surface  73 , and the face  75  has a larger inner diameter than the portion of the sidewall  72  behind it. The oblique face  75  is directed forward and into the connector  10 , toward the axis A. 
     From the oblique face  75 , the compression collar  12  continues to extend axially forward with a constant-diameter sidewall  72  until a ring  76  at the front end  70 . The ring  76  is an annular constriction of the sidewall  72 , extending radially into the interior space within the compression collar  13 , and defining a constricted forward mouth of the compression collar  13 . The thickness of the ring  76 , between its inner and outer diameters, is approximately one-third to one-half larger than the thickness of the sidewall  72  between its inner and outer surfaces  73  and  74  behind the ring  76 . The inner diameter of the ring  76  corresponds to the outer diameter of channel  60  in the front sleeve  50 . 
     The ring  76  is a projection extending radially inward. It includes a blunt front face  80 , an oblique face  81 , an inner face  82 , and the rear face  83 . The front face  80  is normal to the axis A, and the inner face  82  is parallel to it. The oblique face  81  extends between the front and inner faces  80  and  82  at a low angle degree angle, though other angles are suitable as well. The rear face  83  of the ring  76  is normal to the axis A and is directed toward the rear end  71  of the compression collar  13 . 
     In operation, the cable connector  10  is useful for securely coupling a coaxial cable to an electronic component in electrical communication. Operation of the connector  10  is shown sequentially in  FIGS. 2A-2C , which does not show a cable, and in  FIGS. 3A-3C , which does show a coaxial cable  90 . The cable  90  must be prepared before installation. Preparation is conventional and need not be described in detail, but involves stripping back a jacket  91  to expose the center conductor  92 , a dielectric insulator  93 , a flexible shield  94 , and sometimes a braid. The prepared end of the coaxial cable  90  is introduced to the connector  10  by registering the center conductor with the opening at the rear end  71  of the compression collar  13  and advancing the cable  90  therethrough. The connector  10  is initially in an uncompressed condition, and the compression collar  13  is in the retracted position, as shown in  FIGS. 1, 2A, and 3A . 
     In the retracted position of the compression collar  13 , the front end  70  of the compression collar  13  is behind the channel  60  and the ridge  61 , such that the ring  76  is disposed between the ridge  61  and the shoulder  62 . The lip  77  at the rear end  71  of the compression collar  13  is flush against the rear end  41  of the barrel  11 . The compression collar  13  does not compress, deform, or bias the barrel  11  or any part of the barrel  11 . Rather, the compression collar  13  is merely fit to the barrel  11 . 
     The coaxial cable  90  is advanced into the interior space of the barrel  11  and over the inner post  14  until the dielectric insulator  93  is proximate to the front end  20  of the inner post  14 , the jacket  91  (with the flexible shield  94  bent over it) is proximate to the front flange  45 , and the center conductor  92  extends beyond the front end  30  of the coupling nut  12 . In this arrangement, the coaxial cable is fully applied into the connector  10 , but the connector  10  is not yet secured on the coaxial cable  90 . This is shown in  FIG. 1  and  FIG. 3A . 
     To secure the connector  10  on the coaxial cable  90 , the compression collar  13  is advanced forwardly along the direction indicated by the arrowed line B in  FIG. 1B . Briefly, forward movement of the compression collar  13  is preferably accomplished by a compression tool, but in some cases may be possible manually by hand. Certain designs of connectors, especially those with specially-designed coupling nuts  12 , will accommodate manual, tool-less, hand installation. Forward movement advances the compression collar  13  forwardly over the barrel  11  out of the retracted position. In the retracted position, the lip  77  is initially disposed against the rear end  41  of the barrel  11 , and the ring  76  is disposed between the ridge  61  and the shoulder  62 . The oblique face  75  of the compression collar  13  is disposed in contact against the oblique rear face  54  of the front sleeve  50  of the barrel  11 . 
     As shown in both  FIGS. 2A and 3A , when the compression collar  13  is advanced forward along the arrowed line B, the oblique face  75  slides against the rear face  54  of the front sleeve  50 . Because the compression collar  13  is constructed of strong, hard, rigid, resilient, and durable material characteristics, it urges the rear face  54  radially inward in deformation, as shown in  FIGS. 2B and 3B  by the two arcuate lines C. Moreover, the lip  77  pushes the rear sleeve  51  axially forwardly while the rear face  54  is being urged inwardly. The sidewall  42  at the frangible band  52  is thin in comparison to the rest of the barrel  11 , and so the force of the deformation is concentrated here, causing the frangible band  52  to tear. With continued application of force, the frangible band  52  breaks completely, severing and separating the front sleeve  50  from the rear sleeve  51 . 
       FIGS. 2B and 3B  thus show the front sleeve  50  in a deformed condition, beginning its deformation into the connector  10  by the advancing compression collar  13  and the rear sleeve  51  it pushes axially forward. The rear end of the front sleeve  50 , proximate the rear face  54 , becomes increasingly deflected radially inward as the compression collar  13  advances. The rear face  54  slides under, or within, the rear sleeve  51 . The front sleeve  50 , behind the front flange  45 , deforms to accommodate the rear face  54  beginning to slide under the rear sleeve  51 . The gap or distance between the ridges  25  and  26  on the inner post  14  and the inner surface of the barrel  11  at the rear of the front sleeve  50  decreases. The rear sleeve  51  is a now free piece contained within the connector  10  by the sidewall  72  and lip  77  of the compression collar  13 , and the outer surface  44  of the barrel  11  along the front sleeve  50 . 
     In  FIGS. 2B and 3B , the ring  76  and the front end  70  of the compression collar  13  are not yet in the channel  60  of the barrel  11 , and so the compression collar  13  can be further advanced along line B. Further advancement arranges the connector  10  as shown in  FIGS. 2C and 3C , with the compression collar  13  in the advanced position thereof. The ring  76  moves over the ridge  61  and is snappedly received and seated into the channel  60  in front of the ridge  61 . The ridge  61  is forwardly-directed and so prevents retraction of the ring  76  out of the channel  60  and thus prevents retraction of the compression collar  13  off of the barrel  11 . 
     As shown in  FIGS. 2C and 3C , the rear sleeve  51  has fully deformed the rear portion of the front sleeve  50  radially inward. This deformed portion is identified with the reference character  55 , and extends form the annular channel  60  back to the rear face  54 . It is annular, and is obliquely arranged from the ring  65  of the compression collar  13  to between the ridges  25  and  26  of the inner post  14 . The front sleeve  50  is thus deformed from the shoulder  61  rearward. It can be seen in  FIG. 3C  that the deformed portion  55  of the barrel  11  has reduced the space between the barrel  11  and the inner post  14 —between the inner surface of the barrel  11  and the outer surface  24  of the inner post  14 . This gap is not just reduced in a single annular location, but is reduced across nearly the entire of the length of the front sleeve  50 , along the deformed portion  55 , from the torn frangible band  52  to the front flange  45 . As such, the barrel  11  crimps the cable  90  along a considerable length of the cable  90 , thereby preventing the cable  90  from getting “pinched” at a single location. This mitigates any local force concentrations on the cable  90 , local and extreme deformation of the cable, and mitigates any disruption to the magnetic field created by the cable  90 . 
     In the advanced position of the compression collar  13 , the rear sleeve  51  “floats” within the interior of the connector  10  because it is free, but it is also generally prevented from axial, radial, or rotational movement by its tight fit between the inner surface  73  of the compression collar  13 , the lip  77 , and the outer surface  44  of the barrel  11  at the front sleeve  50 . Further, the rear sleeve  51  prevents the cable  90  from being retracted; if the cable  90  is inadvertently pulled backward, it urges the deformed front sleeve  50  radially outward, in confrontation with the rear sleeve  51 . The rear sleeve  51 , however, is bound on all sides and cannot move. Since the rear sleeve  51  is hard, it prevents the deformed front sleeve  50  from being moved radially outward, and thereby prevents the cable  90  from being pulled out of the connector  10 . 
       FIGS. 4-6C  illustrate another coaxial cable connector with a frangible inner barrel (hereinafter, “connector  110 ”).  FIG. 4  is an elevation view of the connector, and  FIG. 5A  is a section view bisecting the connector  110  along the line  5 - 5  in  FIG. 4 . The connector  110  includes a body or barrel  111 , a coupling nut  112  mounted for rotation on the barrel  111 , a compression collar  113  mounted to the barrel  111  for axial movement between retracted and advanced positions with respect to the barrel  111 , and an inner post  114 , on which both the barrel  111  and the coupling nut  112  are mounted. A longitudinal axis C extends through the center of the connector  110 , generally defining an axis of rotational symmetry for the connector  110 . 
     The inner post  114  is an elongate sleeve extending along the longitudinal axis D and having rotational symmetry thereabout. The inner post  114  includes opposed front and rear ends  120  and  121 , a sidewall  122  extending therebetween, and opposed inner and outer surfaces  123  and  124 . The outer surface  124  at the rear end  121  of the inner post  114  is formed with two annular barbs or ridges  125  and  126  projecting toward the front end  120  and radially outward from the longitudinal axis D. The ridges  125  and  126  are laterally or axially spaced apart from each other along the rear end  121  of the inner post  114 . The ridges  125  and  126  are spaced apart from each other significantly more so than are the ridges  125  and  126  in the connector  110 . The ridges  125  and  126  provide grip on a cable applied to the connector  110  to resist withdrawal of the cable from the connector  110 , and also provide an increased diameter on the inner post  114  over which the cable must be passed. In some embodiments, the inner post  114  may have other designs or structures, such as a shortened axial length. 
     The coupling nut  112  is mounted for rotation at the front end  120  of the inner post  114 . The coupling nut  112  is a sleeve having opposed front and rear ends  130  and  131 , an integrally-formed ring portion  132  proximate to the front end  130 , and an integrally-formed nut portion  133  proximate to the rear end  131 . The ring portion  132  has a smooth annular outer surface and an opposed inner surface which may be smooth, threaded, ribbed, or otherwise configured for engaging with a female RF mating post of an electronic component. The nut portion  133  of the coupling nut  112  has a hexagonal outer surface to receive the jaws of a tool. The coupling nut  112  is constructed of a material or combination of materials having strong, hard, rigid, durable, and high electrically-conductive material characteristics, such as metal. A gasket  134  disposed between the inner post  114  and the coupling nut  112  is constructed of a deformable yet resilient material, such as rubber, which prevents the intrusion of moisture into the connector  110 , and maintains a tight fit between the coupling nut  112  and the inner post  114 . In this way, a permanent, low-friction connection is established that allows the coupling nut  112  to rotate freely upon the inner post  114  about the axis D while still maintaining the coupling nut  112  and the inner post  114  in permanent electrical communication. In some embodiments, the gasket  134  may be omitted, and so the gasket  134  is not shown in other drawings of the connector  110 . Moreover, in some embodiments of the connector  110 , the coupling nut  112  may have another design, such as press- or push-on design, collet design, or other design which involves different structure. As such, the coupling nut  112  can be considered a “coupling interface.” 
     The construction, structure, and arrangement of the coupling nut  112  and the inner post  114  are not critical features of this inventive connector, and it is noted that any suitable coupling nut and inner post may be used in the spirit of the discussion herein. The discussion now turns to the barrel  111 , the compression collar  113  mounted over the barrel, and how those two elements are constructed, arranged, and operated within the connector  110 . 
     Referring primarily to  FIG. 5A , the barrel  111  is an elongate, cylindrical sleeve extending along the longitudinal axis D with rotational symmetry thereabout, and is constructed of a material or combination of materials having strong, rigid, size memory, and shape-memory material characteristics, as well as a low coefficient of friction, such as plastic, metal, or the like. The barrel  111  receives and securely holds a cable introduced into the connector  110 . 
     The barrel  111  has opposed front and rear ends  140  and  141  with a cylindrical sidewall  142  extending therebetween, which sidewall  142  has opposed inner and outer surfaces  143  and  144 . The inner surface  143  defines and bounds a cable-receiving interior space shaped and sized to receive the coaxial cable, and in which the rear end  121  of the inner post  114  is disposed. An opening at the rear end  141  of the barrel  111  communicates with this cable-receiving interior space. 
     A front flange  145  is at the front end  140  of the barrel  111 . The front flange  145  is a large, inwardly-turned annular lip which abuts and is seated on the outer surface  124  of the inner post  114  behind its front end  120 . The front flange  145  is seated and secured on the outer surface  124  with a friction fit, thereby securing the barrel  111  on the inner post  114 . 
     The sidewall  142  of the barrel  111  extends rearwardly from the front flange  145 , and the front flange  145  has a smaller inner diameter than any part of the sidewall  142  behind the front flange  145 . Briefly, some terms are used with respect to the embodiment of the connector  110  to refer to direction or location. “Rearwardly,” “behind,” and similar terms indicate that something extends, is directed, or is located proximate to or toward the rear end  141  of the barrel  111 . Conversely, “forwardly,” “ahead,” and similar terms indicate that something extends, is directed, or is located proximate to or toward the front end  130  of the coupling nut  112 . 
     The barrel  111  is constructed from a front sleeve  150 , a middle sleeve  151 , and a rear sleeve  152  which are integrally and monolithically formed to each other at annular, frangible bands  153  and  154 . Nevertheless, the forward, middle, and rear sleeves  150 ,  151 , and  152  are frangible; they are designed to separate from each other within the compression collar  113 . Explained in more detail below, the front and rear sleeves  150  and  152  flank the middle sleeve  151 , and when the compression collar  113  advances forward, the middle sleeve  151  separates from the front and rear sleeves  150  and  152  and slides between and under each of them. The front sleeve  150  deforms slightly, and the middle sleeve  151  is pushed radially inward. The barrel  111  is constructed to cause this separation in response to axial compression of the connector  110 . The middle sleeve then captures the applied cable. 
     Still referring to  FIG. 5A , the rear sleeve  152  is a short, cylindrical collar or cuff. The rear sleeve  152  includes the rear end  141  and the sidewall  142  of the barrel  111 . From the rear end  141 , the rear sleeve  152  extends forwardly to the frangible band  154 , a rearward frangible band  154 . A flat or blunt front face  155  projects radially outward from the frangible band  154 . The front face  155  is roughly perpendicular to the axis D and defines the forward termination of the rear sleeve  152 . The front face  155  has a height, from the frangible band  154  to the outer surface  124 , which is approximately equal to that of the front sleeve  150 , as defined below. The rear sleeve  152  is substantially rigid and maintains its shape and size during movement and arrangement of the connector  110 . In this way, the rear sleeve  152  moves with the compression collar  113 , in which it is encased, when the connector  110  is secured on the cable. 
     In front of the rear sleeve  152 , the middle sleeve  151  is a cylindrical collar or cuff, slightly longer than the rear sleeve  152 , and includes oblique rear and front faces  156  and  157  with a constant-thickness middle section therebetween. The oblique rear face  156  is oriented radially inward and axially forward, such that the rear face  156  presents radially outward and axially forward. The oblique front face  157  is oriented radially inward and axially rearward, such that the front face  157  presents radially outward and axially rearward. In this way, the rear and front faces  156  and  157  are annular ramps over which the front and rear sleeves  150  and  152 , respectively, are driven when the connector  110  is compressed, as will be discussed. The middle sleeve  151  flanks the ridges  125  and  126 ; the front end of the middle sleeve  151  is in front of the ridge  125  and the rear end of the middle sleeve  151  is behind the ridge  126 . 
     The rear sleeve  152  is joined to the middle sleeve  151  at the rearward frangible band  154 . The frangible band  154  is the union between the middle sleeve  151  and the rear sleeve  152 . Before the connector  110  is compressed, the barrel  111  is preferably a single, integral, monolithic piece and the middle sleeve  151  and rear sleeve  152  are constituent elements of that piece. The frangible band  154  joins the middle sleeve  151  to the rear sleeve  152 ; it is an axially-narrow, radially-thinned portion of the sidewall  142  of the barrel  111  formed between the rear face  156  of the middle sleeve  151  and the front face  155  of the rear sleeve  152 . The frangible band  154  is preferably a thinned portion of the sidewall  142  which is continuous and annular and formed entirely to each of the rear face  156  and the front face  155 . In alternate embodiments, however, the frangible band  154  has another structure, such as a series of small, circumferentially-separated fingers of the sidewall  142  formed between the two faces  156  and  155 , or some other structure. 
     The frangible band  154  is radially encircled by the front face  155  of the rear sleeve  152 , which front face  155  projects radially outward from the frangible band  154 . The frangible band  154  is radially closer to the axis D than is the front face  155 . Moreover, the rear face  156  of the middle sleeve rises obliquely away from the frangible band  154 . Thus, a V-shaped annular notch  164  is defined above—or just radially beyond the frangible band  154 —encircling the band  154 . The notch  164  is bound by the frangible band  154 , the rear face  156 , and the compression collar  113 . 
     In front of the middle sleeve  151 , the front sleeve  150  is a cylindrical collar or cuff, slightly longer than the rear sleeve  152  and about the same length as the middle sleeve  151 . It includes the front end  140  of the barrel  111  and the sidewall  142  extending rearwardly therefrom to a blunt rear face  158 . Indeed, the front sleeve  150  extends from the front end  140  to the forward frangible band  153 , because the frangible band  153  is formed between the front face  157  and the rear face  158 . The rear face  158  is roughly perpendicular to the axis D and defines the rearward termination of the front sleeve  150 . The rear face  158  has a height, from the forward frangible band  153  to the outer surface  144 , which is approximately half the thickness of the middle sleeve  151  at its largest point between its inner and outer surfaces  143  and  144 , in the middle section between the front and rear faces  157  and  156 . 
     The front sleeve  150  further includes the front flange  145  and an annular channel  160 , just behind the front flange  145 , recessed into the sidewall  122  from the outer surface  124 . Proximate to the channel  160 , and cooperating with the front flange  145  to bound the channel  160  is a forward barb or ridge  161  which rises radially outward, such that when the compression collar  113  is advanced axially over it, the compression collar  113  biases the ridge radially inwardly slightly. Behind the ridge  161 , the outer diameter of the sidewall  122  decreases slightly until it terminates at the blunt rear face  162 . The flat rear face  162  projects radially inward from the outer diameter of the sidewall  122  to the forward frangible band  154 . 
     The front sleeve  150  is joined to the middle sleeve  151  at the forward frangible band  153 . The frangible band  153  is the union between the front and middle sleeves  150  and  151 . Before the connector  110  is compressed, the barrel  111  is preferably a single, integral, monolithic piece and the front and middle sleeves  150  and  151  are constituent elements of that piece. The frangible band  153  joins the front sleeve  150  to the middle sleeve  151 ; it is an axially-narrow, radially-thinned portion of the sidewall  142  of the barrel  111  formed between the rear face  158  of the front sleeve  150  and the front face  157  of the middle sleeve  151 . The frangible band  153  is preferably a thinned portion of the sidewall  142  which is continuous and annular and formed entirely to each of the rear face  158  and the front face  157 . In alternate embodiments, however, the frangible band  153  has another structure, such as a series of small, circumferentially-separated fingers of the sidewall  142  formed between the two faces  157  and  158 , or some other structure. 
     The frangible band  153  is radially encircled by the rear face  158  of the front sleeve  150 , which rear face  158  projects radially outward from the frangible band  153 . The frangible band  153  is radially closer to the axis D than is the rear face  158 . Moreover, the front face  157  of the middle sleeve  151  rises obliquely away from the frangible band  153 . Thus, a V-shaped annular notch  163  is defined above—or just radially beyond—the frangible band  153 , encircling the band  153 . The notch  163  is bound by the frangible band  153 , the front face  157 , and the compression collar  113 . 
     Still referring to  FIG. 5A , the compression collar  113  is mounted for reciprocal axial movement over the barrel  111 . It includes opposed front and rear ends  170  and  171 , an annular sidewall  172  extending between the front and rear ends  170  and  171 , and opposed inner and outer surfaces  173  and  174 . An interior space bound by the inner surface  173  extends into the compression collar  113  from an opening formed at the rear end  171  of the compression collar  113 . The interior space is a cylindrical bore and is sized to receive the barrel  111  with the coaxial cable carried within. The compression collar  113  is fit onto the rear end  141  of the barrel  111  to limit the relative radial and rotational movement of the compression collar  113  on the barrel  111  with respect to the axis D. The compression collar  113  is constructed of a material or combination of materials having strong, hard, rigid, resilient, and durable material characteristics, such as metal, plastic, or the like. The compression collar  113  does not deform in response to movement between its retracted and advanced positions, or in response to deformation, movement, or other change of the barrel  111  within. 
     The compression collar  113  has a constant outer diameter from the front end  170  to just before the rear end  171 . Most of the length of the sidewall  172  has one of two inner diameters; a larger inner diameter proximate the front end  170  (and resulting in a thinner sidewall  172  there) and a smaller inner diameter proximate the rear end  171  (and resulting in a thicker sidewall  172  there). At the rear end  171 , the sidewall  172  has an inwardly-directed lip  177 . The lip  177  has a reduced inner diameter relative the rest of the compression collar  113 , and its inner diameter is smaller than the inner diameter of the barrel  111  at its rear end  141 . Indeed, the inner diameter of the lip  177  is even smaller than the inner diameter of the barrel  111  at the rear end  141  of the barrel  111 , such that it hangs over the rear end  141 . The lip  177  serves as a stop against the barrel  111 , so that, when the compression collar  113  is moved forward, the lip  177  contacts the rear end  141  of the barrel  111  and pushes the rear end  141  forward along the axis D, thereby urging compression of the barrel  111 . 
     The inner diameter of the compression collar  113  is constant from the lip  177  forward, until an oblique face  175  approximately halfway along the length of the compression collar  113 . The oblique face  175  extends into the sidewall  172 , reducing its inner diameter. The oblique face  175  is an annular expansion extending radially into the sidewall  172  from the inner surface  173 , and it has a larger inner diameter than the portion of the sidewall  172  behind it. The oblique face  175  is directed forward and into the connector  110 , toward the axis D. 
     From the oblique face  175 , the compression collar  112  continues to extend axially forward with a thinner sidewall  172  until a ring  176  at the front end  170 . The ring  176  is an annular constriction of the sidewall  172 , extending radially into the interior space within the compression collar  113 , and defining a constricted forward mouth of the compression collar  113 . The thickness of the ring  176 , between its inner and outer diameters, is approximately one-third to one-half larger than the thickness of the sidewall  172  between its inner and outer surfaces  173  and  174  behind the ring  176 . The inner diameter of the ring  176  corresponds to the outer diameter of channel  160  in the front sleeve  150 . 
     The ring  176  is a projection extending radially inward. It includes a blunt front face  180 , an oblique face  181 , an inner face  182 , and the rear face  183 . The front face  180  is normal to the axis D, and the inner face  182  is parallel to it. The oblique face  181  extends between the front and inner faces  180  and  182  at a low angle degree angle, though other angles are suitable as well. The rear face  183  of the ring  176  is normal to the axis D and is directed toward the rear end  171  of the compression collar  113 . 
     In operation, the cable connector  110  is useful for securely coupling a coaxial cable to an electronic component in electrical communication. Operation of the connector  110  is shown sequentially in  FIGS. 5A-5C , which does not show a cable, and in  FIGS. 6A-6C , which does show the cable  90  used in the above description of the connector  110 . As above, preparation is conventional and need not be described in detail, but involves stripping back the jacket to expose the center conductor, a dielectric insulator, a flexible shield, and sometimes a braid. The connector  110  is initially in an uncompressed condition, and the compression collar  113  is in the retracted position, as shown in  FIGS. 4, 5A, and 6A . 
     In the retracted position of the compression collar  113 , the front end  170  of the compression collar  113  is behind the channel  160  and the ridge  161 , such that the ring  176  is disposed between the ridge  161  and the forward frangible band  153 . The lip  177  at the rear end  171  of the compression collar  113  is flush against the rear end  141  of the barrel  111 , and the compression collar  113  does not compress, deform, or bias the barrel  111  or any part of the barrel  111 . Rather, the compression collar  113  is merely fit to the barrel  111 . 
     The coaxial cable  90  is advanced into the interior space of the barrel  111  and over the inner post  114  until the dielectric insulator  93  is proximate to the front end  120  of the inner post  114 , the jacket  91  (with the flexible shield  94  bent over it) is proximate to the front flange  145 , and the center conductor  92  extends beyond the front end  130  of the coupling nut  112 . In this arrangement, the coaxial cable is fully applied into the connector  110 , but the connector  110  is not secured on the coaxial cable  90 . This is shown in  FIGS. 4 and 6A . 
     To secure the connector  110  on the coaxial cable, the compression collar  113  is advanced forwardly along the direction indicated by the arrowed line E in  FIGS. 5A and 6A . Briefly, forward movement of the compression collar  113  is preferably accomplished by a compression tool, but in some cases may be possible manually by hand. Certain designs of connectors, especially those with specially-designed coupling nuts  112 , will accommodate manual, tool-less, hand installation. Forward movement advances the compression collar  113  forwardly over the barrel  111  out of the retracted position. In the retracted position, the lip  177  is initially disposed against the rear end  141  of the barrel  111 , and the ring  176  is disposed between the ridge  161  and the forward frangible band  153 . The oblique face  175  of the compression collar  113  is disposed in contact against the sloping rear face  156  of the middle sleeve  151  of the barrel  111 . 
     As shown in both  FIGS. 5A and 6A , when the compression collar  113  is advanced forward along the arrowed line E, the oblique face  175  slides against the sloping rear face  156  of the middle sleeve  151 . Because the compression collar  113  is constructed of strong, hard, rigid, resilient, and durable material characteristics, it urges the sloping rear face  156  radially inward in deformation, as shown in  FIGS. 5B and 6B  by the two arrowed lines F. Moreover, the lip  177  pushes the rear sleeve  152  axially forwardly while the sloping rear face  156  is being urged inwardly. The sidewall  142  at the frangible band  153  is thin in comparison to the rest of the barrel  111 , and so force of the deformation is concentrated here. However, the forward frangible band  153  is also a thin portion of the sidewall  142 , and so deformation is concentrated here as well. As such, when the sloping rear face  156  is urged inwardly, the middle sleeve  151  hinges at the forward frangible band  153 , which yields and severs in response. Both frangible bands  153  and  154  tear. The tearing of the forward frangible band  153  and the rearward frangible band  154  severs and separates the middle sleeve  151  from both the front sleeve  150  and the rear sleeve  152 . 
     The sloping rear face  156  begins to slide under, or within, the rear sleeve  152 , and the sloping front face  157  begins to slide under, or within, the front sleeve  150  at the flat rear face  158 . The front sleeve  150 , behind the front flange  145 , tends to maintain its cylindrical shape once the middle sleeve  151  has detached from it. The front and rear sleeves  150  and  152  thus move axially together with respect to each other, and the middle sleeve  151  is pushed radially inward along the arrowed lines F by the axial closure of space between the front and rear sleeves  150  and  152  as the compression collar  113  moves axially forward. The gap or distance between ridges  125  and  126  on the inner post  114  and the inner surface  143  of the middle sleeve  151  decreases. The middle sleeve  151  is a now free piece contained within the connector  110  by the sidewall  172  of the compression collar  13 , the front face  155  of the rear sleeve  152 , and the rear face  158  of the front sleeve  150 . 
     In  FIG. 6B , the ring  176  and the front end  170  of the compression collar  113  are not yet in the channel  160  of the barrel  111 , and so the compression collar  113  can be further advanced along line E. Further advancement arranges the connector  110  as shown in  FIGS. 5C and 6C , with the compression collar  113  in the advanced position thereof. Here, the ring  176  is snappedly received and seated into the channel  160  in front of the ridge  161 . The ridge  161  prevents retraction of the ring  176  out of the channel  160  and thus prevents retraction of the compression collar  113  off of the barrel  111 . 
     As shown in  FIGS. 5C and 6C , the middle sleeve  151  has fully moved radially inward. In  FIGS. 5C and 6C , it can be seen that the moved middle sleeve  151  has reduced the gap between the outer surface  124  of the inner post  114  and the inner surface  143  of the barrel  111  (or what was once the barrel  111 —the middle sleeve  151 ). This gap is not just reduced in a single annular location, but is reduced across the entire of the length of the middle sleeve  151 , from the torn frangible band  153  to the torn frangible band  154 . As such, the middle sleeve  151  crimps the cable  90  along a considerable length of the cable  90 , thereby preventing the cable  90  from getting “pinched” at a single location. 
     In the advanced position of the compression collar  113 , both the rear sleeve  152  and the middle sleeve  151  “float” within the interior of the connector  110  because each is free. However, the rear sleeve  152  is nevertheless prevented from axial, radial, or rotational movement by its tight fit between the inner surface  173  of the compression collar  113 , the lip  177 , and the sloping rear face  156  of the middle sleeve  151 . Similarly, the middle sleeve  151  is also prevented from axial, radial, or rotational movement by its tight fit between the cable  90  and the front and rear sleeves  150  and  152  encircling it. Further, this arrangement prevents the cable  90  from being retracted; if the cable  90  is inadvertently pulled backward, it would urge the separated middle sleeve  151  radially outward, in confrontation with both of the front and rear sleeves  150  and  152 . However, the front and rear sleeves  150  and  152  are both bound and not moveable. Since the front and rear sleeves  150  and  152  are hard, they prevent the middle sleeve  151  from being moved radially outward, and thereby prevent the cable  90  from being pulled out of the connector  110 . 
     A preferred embodiment is fully and clearly described above so as to enable one having skill in the art to understand, make, and use the same. Those skilled in the art will recognize that modifications may be made to the description above without departing from the spirit of the invention, and that some embodiments include only those elements and features described, or a subset thereof. To the extent that modifications do not depart from the spirit of the invention, they are intended to be included within the scope thereof.