Abstract:
A coaxial cable connector is provided for attachment to a corrugated coaxial cable. The coaxial cable connector includes a clamping member with at least two projections configured to engage the outer corrugated conductor where the corrugated conductor has a diameter that is the smallest. The coaxial cable connector also includes seals to protect the coaxial cable connector from the elements. An alternative embodiment includes a third projection to engage the outer corrugated conductor to provide support for the coaxial cable.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of, and priority to U.S. Provisional Patent Application No. 61/004,011 filed on Nov. 21, 2007, the content of which is relied upon and incorporated herein by reference in its entirety. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to connectors for coaxial cables and, more particularly, to connectors for coaxial cables which have annularly corrugated outer conductors. 
   2. Technical Background 
   A coaxial cable is characterized by having an inner electrical conductor, an outer electrical conductor, and an insulator between the inner and outer electrical conductors. The inner electrical conductor may be hollow or solid. At the end of coaxial cable, a connector is attached to allow for mechanical and electrical coupling of the coaxial cable. 
   Connectors for coaxial cables have been used throughout the coaxial cable industry for a number of years. One type of coaxial cable has an annularly corrugated outer conductors and plain cylindrical inner conductors. Generally, connectors for these coaxial cables are different from those where the outer electrical conductors are smooth or uncorrugated. As an example, one connector has a single annular clamping portion that meshes with the last valley in the corrugated outer conductor providing a single circumferential point of contact. Without additional axial reinforcement from the coaxial cable connector, physical gyrations of the cable found in field applications due to weather and vibration can cause undue stress and, ultimately, material fatigue of the corrugated cable outer conductor. 
   Therefore, there is a continuing need for improved high performance coaxial cable connectors that are easy and fast to install and un-install, particularly under field conditions. Also, since these connectors are generally installed in the field, they should be pre-assembled into one piece connectors, so that the possibility of dropping and losing small parts, misplacing O-rings, damaging or improperly lubricating O-rings, or other assembly errors in the field is minimized. Additionally, it should be possible for the coaxial cable connector to be installed and removed without the use of any special tools. 
   SUMMARY OF THE INVENTION 
   Disclosed herein is a coaxial cable connector for attachment to a coaxial cable, the coaxial cable comprising a center conductor, a dielectric layer surrounding the center conductor, and an outer corrugated conductor surrounding the dielectric layer, the coaxial cable connector includes a rear outer body having a front end, a back end, an external gripping portion, and a longitudinal opening extending between the front end and the back end along a longitudinal axis, a clamping member rotatably mounted within the longitudinal opening in the rear outer body from the front end thereof, the clamping member having an internal surface with at least two projections configured to engage the outer corrugated conductor where the corrugated conductor has a diameter that is the smallest, a front body having a front end, a back end, an external gripping portion, and a longitudinal opening extending between the front end and the back end along a longitudinal axis, an insulator disposed in the front body, the insulator having an opening therein coaxial with the longitudinal axis of the front body, a contact element disposed in the opening of the insulator, the contact element having a back end configured to engage the center conductor of the corrugated coaxial cable. 
   In another aspect, a combination of a corrugated coaxial cable and a coaxial connector is disclosed, the coaxial cable comprising a center conductor, a dielectric layer surrounding the center conductor, an outer corrugated conductor surrounding the dielectric layer, and a jacket surrounding the outer corrugated conductor, the coaxial cable connector includes a rear outer body having a front end, a back end, an external gripping portion, and a longitudinal opening extending between the front end and the back end along a longitudinal axis, a clamping member rotatably mounted within the longitudinal opening in the rear outer body from the front end thereof, the clamping member having an internal surface with at least two projections engaging the outer corrugated conductor where the corrugated conductor has a diameter that is the smallest, a front body having a front end, a back end, an external gripping portion, and a longitudinal opening extending between the front end and the back end along a longitudinal axis, an insulator disposed in the front body, the insulator having an opening therein coaxial with the longitudinal axis of the front body, and a contact element disposed in the opening of the insulator, the contact element having a back end engaging at least a portion of the center conductor of the corrugated coaxial cable. 
   Additional features and advantages of the invention will be set forth in the detailed description which follows and, in part, will be readily apparent to those skilled in the art from that description or recognized by practicing the invention as described herein, including the detailed description which follows, the claims, and the appended drawings. 
   It is to be understood that both the foregoing general description and the following detailed description of the present embodiments of the invention are exemplary and explanatory, and are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the invention and, together with the description, serve to explain the principles and operations of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is cross-sectional view of one embodiment of a partially assembled coaxial cable connector according to the present invention and a portion of a corrugated coaxial cable; 
       FIG. 2  is an exploded, cross-sectional view of the coaxial cable of  FIG. 1 ; 
       FIG. 3  is a cross-sectional view of the connector of  FIG. 1  with a rear subassembly installed on the coaxial cable and the front subassembly prior to connection with the rear subassembly; 
       FIG. 4  is cross-sectional view of the connector of  FIG. 1  with coaxial cable connector partially installed on the corrugated coaxial cable; 
       FIG. 5  is a cross-sectional view of the connector of  FIG. 1  with coaxial cable connector fully installed on the corrugated coaxial cable; and 
       FIG. 6  is a view of another embodiment of a coaxial cable connector according to the present invention fully installed on a portion of a corrugated coaxial cable. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Reference will now be made in detail to the present preferred embodiment(s) of the invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. 
   Referring to  FIGS. 1 &amp; 2 , a cross sectional view of a portion of a corrugated coaxial cable  100  and a corrugated coaxial cable connector  200  are illustrated. The corrugated coaxial cable  100  includes center conductor  105 , dielectric  120 , corrugated outer conductor  125  and jacket  130 . Center conductor  105  is preferably annular and has an inside diameter  110  and outside diameter  115 . 
   Corrugated coaxial cable connector  200  is preferable preassembled in a factory and includes a rear subassembly  202  and a front subassembly  204 +The subassemblies  202 ,  204  are preferably attached to one another so that they can be shipped from the factory to the field as described in more detail below. 
   The rear subassembly  202  includes a rear outer body  206  having a front end  208 , a backend  210 , an external gripping portion  212  and a longitudinal opening  214  extending between the front end  208  and the back end  210  along the longitudinal axis A. The rear outer body  206  preferably includes a threaded portion  216  adjacent the front end  208  for threadingly engaging the front subassembly  204 . Rear outer body  206  is preferably made from a metallic material such as brass and is preferable plated with a conductive, corrosion resistant material such as a nickel-tin alloy. 
   The rear subassembly  202  also includes a clamping member  220 , which is preferably made from a plastic material such as acetal, but may be made from a metallic material such as brass and plated with a conductive, corrosion resistant material such as a nickel-tin alloy. Clamping member  220  is secured within the longitudinal opening  214  of rear outer body  206  by way of a free-rotating snap fit. Preferably, the clamping member  220  is secured in the rear outer body  206  in the factory. Clamping member  220  has a front end  222 , a back end  224 , and a longitudinal opening  226 . At the front end  222 , the clamping member  220  has a chamfered portion  228  leading to a first inwardly projecting protrusion  230  on the internal surface  232  of the longitudinal opening  226 . A second inwardly projecting protrusion  234  is also present on the internal surface  232 , disposed rearwardly from the first inwardly projecting protrusion  230 . Preferably, the inwardly projecting protrusions  230 ,  234  are annular protrusions and extend around the longitudinal opening  226 . However, they may also be segmented or non-continuous and still be within the scope of the present invention. As discussed in more detail below, the inwardly projecting protrusions  230 ,  234  engage the corrugated outer conductor  125  where the corrugated outer conductor  125  has the smallest diameter, i.e., the valleys of the corrugated outer conductor  125 . The front end  222  of clamping member  220  preferably has a plurality of slots  240 , resulting in the front end  222  having a plurality of fingers or flexible beams  242 . The presence of the flexible beams allows the clamping member  220  to slide over the corrugated coaxial cable  100 , and in particular, the corrugated outer conductor  125 . 
   The front subassembly  204  includes front body  260 , insulator  300 , and contact element  320 . The front body  260  has a front end  262 , a back end  264 , an external gripping portion  266 , and a longitudinal opening  268  extending between the front end  262  and the back end  264  along the longitudinal axis A. The front body  260  also has a radiused annular shoulder  270  and internal threaded portion  272 . As discussed in more detail below, the radiused annular shoulder  270  cooperates with the chamfered portion  228  of the clamping member  220  to capture the corrugated outer conductor  125  to secure the connector  200  to the coaxial cable  100 . The internal threaded portion  272  cooperates with the threaded portion  216  of rear outer body  206  to secure the rear subassembly  202  and the front subassembly  204 . Front body  260  is preferably made from a metallic material such as brass and is preferable plated with a conductive, corrosion resistant material such as a nickel-tin alloy. Insulator  300  includes a bore  302  aligned on longitudinal axis A and an outer surface  284 . Insulator  300  is made from an electrically insulative material such as acetal and assists in centering and supporting contact element  320 . Contact element  320  has a back end  322  that includes a tapered portion  324  that engages center conductor  105 . Contact element  320  also preferably has a plurality of slots  326  at the back end  322  to allow the contact element  320  to flex as necessary to make physical and electrical contact with the central conductor  105 . Contact element  320  is made from a metallic material such as beryllium copper, is preferably heat treated and is preferably plated with a conductive, corrosion resistant material such as a nickel-tin alloy. Contact element  320  has a front end  328  that has a female configuration to receive a male configured contact (not shown). However, the front end  328  of contact element  320  may also have a male configuration. 
   A plurality of seals, preferably in the form of O-rings, are also factory installed in the connector  200  to make it water proof. In the rear subassembly  206 , seats  350 ,  360  and  370  have been installed as illustrated in  FIG. 1 . Seal  350  has been installed in an annular cut-out  352  at the back end  210  of the rear outer body  206 . Seal  350  assists in making the connector  200  water-proof by engaging the jacket  130  of the coaxial cable  100  (see  FIG. 3 ). Seal  360  is installed in an annular cut-out  362  in a medial portion of the rear outer body  206  and seals the junction between the clamping member  220  and the rear outer body  206 . Seal  370  has been installed on the outer surface of the rear outer body  206  in an annular cut-out  372  and, as noted below in conjunction with  FIG. 5 , seals the junction of the rear outer body  206  and the front body  260  when the connector is assembled on the corrugated coaxial cable  100 . 
   Two seals  380 ,  390  are also factory-installed in the front subassembly  204  to seal the connector  200  from the front. Seal  380  has been installed in an annular cut-out  382  on contact element  320  to seal the connector  200  when the contact element  320  is installed in insulator  300 . Similarly, seal  390  is factory-installed in an annular cut-out  392  in insulator  300  to seal the junction between the insulator  300  and the front body  260 . 
   Turning now to  FIG. 3 , the installation of the corrugated coaxial cable connector  200  will now be described. If not already separated from one another, the rear subassembly  202  and front subassembly  204  should be separated from one another, i.e., unscrewed from one another in a preferred embodiment. The rear subassembly  202  is then placed over the corrugated coaxial cable  100 , the corrugated coaxial cable  100  having the jacket  130  stripped back to expose a portion of the corrugated outer conductor  125 . The clamping member  220  slides over the corrugated coaxial cable  100 , and in particular, the corrugated outer conductor  125  with the plurality of fingers or flexible beams  242  flexing sufficiently to allow the rear subassembly  202  to slide on the corrugated coaxial cable  100 . The rear subassembly  202  should naturally rest with the first inwardly projecting protrusion  230  on the internal surface  232  of the longitudinal opening  226  of clamping member  220  in an annular groove of the corrugated outer conductor  125 . The second inwardly projecting protrusion  234  will also be in an annular groove of the corrugated outer conductor  125  and the seal  350  will engage the cable jacket  130 . 
   As illustrated in  FIG. 4 , the front subassembly  204  is partially installed on the rear subassembly  202 , which in this embodiment is done by rotating the rear subassembly  202  and front subassembly  204  relative to one another. During the installation, the contact element  320  is aligned with and engages the inside diameter  110  of the center conductor  105 . The tapered portion  324  assures that the contact element  320  will make physical and electrical contact with the center conductor  105 . To the extent that the contact element  320  is larger than the inside diameter  110  of the center conductor  105 , the slots  326  allow the contact element  320  to radially compress to fit within the center conductor  105 . Simultaneously, the radiused annular shoulder  270  moves between the corrugated outer conductor  125  and the dielectric  120  to pinch the corrugated outer conductor  125  between the radiused annular shoulder  270  and the chamfered portion  228  of the clamping member  220 . 
   In  FIG. 5 , the rear subassembly  202  is fully tightened into front subassembly  204  by further rotation of internal threaded portion  272  of front body  260  and external threaded portion  219  of rear body  206 . It should be noted that the rotational engagement of front body  260  to rear body  206  does not transmit appreciable rotational or torsional load to clamping member  220  as it is a separate member (as well as a free rotating member), thus preventing damage to flexible beams  242  of clamping member  220 . The first inwardly projecting protrusion  230  and second inwardly projecting protrusion  234  contact the corrugated outer conductor  125  at circumferential points B and C, respectively, and corrugated outer conductor  125  is captured between the radiused annular shoulder  270  and the chambered portion  228  of the clamping member  220  providing positive electrical and mechanical communication between corrugated outer conductor  125  and front body  260 . Second inwardly projecting protrusion  234  contacts corrugated outer conductor  125  at circumferential point C and provides additional axial load as well as radial support thus further stabilizing the connector/cable junction. The additional radial support by the second inwardly projecting protrusion  234  is especially helpful to provide strain relief and ensure long term electrical and mechanical stability of the junction. Tertiary circumferential points of support for cable  100  are provided by seals  350  and  360 , particularly since seal  360  is deformed inwardly by the connection of front body  260  to rear outer body  206 . 
   Another embodiment of a corrugated coaxial cable connector  600  according to the present invention is illustrated in  FIG. 6 . Corrugated coaxial cable connector  600  is similar to the first embodiment and has a rear outer body  606 , a clamping member  620 , a front body  660 , insulator  700 , and contact  720 . The corrugated coaxial cable connector  600  also has the same seals, but clamping member  620  has an additional inwardly projecting annular projection  650  at the rear end thereof to engage the corrugated outer conductor  125  and provide a full 360 degree band of support for coaxial cable  100 . 
   It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention. Thus it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.