Center conductor terminal having increased contact resistance

A terminal assembly is provided for terminating a center conductor of a coaxial cable. The terminal assembly includes a terminal body having a pin at one end and a cavity at the other end for accommodating a center conductor therein. A contact member is supported within the cavity. The contact member includes plural inwardly directed cantilevered beams extending from a contact base for deflectable engagement with the inserted center conductor. The terminal body includes an inwardly directed shoulder for engagement with the beams at a location between the base and the distal ends of the beams. The location defines a deflection fulcrum at a location distal from the base so as to provide increased contact engagement force between the distal ends of the beams and the center conductor.

FIELD OF THE INVENTION

The present invention relates to a terminal assembly for terminating the center conductor of a coaxial cable. More specifically, the present invention relates to a terminal assembly which provides increased contact force between a center conductor or a coaxial cable and electrical contact of a pin terminal.

BACKGROUND OF THE INVENTION

Coaxial cables are commonly used in various areas of industry, such as the cable television industry, to carry electrical signals. Coaxial cable connectors are typically used to terminate the coaxial cable to interconnect cables or to connect cables to various components. Once such coaxial connector particularly used for hard line coaxial cable is shown in commonly assigned U.S. Pat. No. 6,331,123, the disclosure of which is incorporated by reference herein for all purposes.

As is well known, a coaxial cable includes an elongate center conductor capable of transmitting electrical signals therethrough. The center conductor is typically surrounded by a dielectric covering. An outer conductor is positioned about the dielectric covering and a cable jacket surrounds the outer conductor. The cable is prepared for termination by removing a portion of the cable jacket at the distal end thereof, folding back the outer conductor and stripping away the dielectric covering from the center conductor thereby exposing an elongate extent of the center conductor. The prepared cable is inserted into a coaxial connector so that the center conductor can be electrically connected to another cable or component to effectively transmit the electrical signal therethrough.

In most instances and as shown in the above referenced incorporated patent, a pin terminal is used terminate the center conductor to allow ease of interconnection of the center conductor to another connector. The pin terminal is an elongate member having a pin at one end and a cavity at the other end. The center conductor is inserted into the cavity where mechanical and electrical engagement therebetween is achieved in order to facilitate the electrical engagement, the cavity in the pin terminal may include a contact having inwardly directed cantilevered fingers for mechanical and electrical engagement with the inserted center conductor. The cantilevered fingers function as deflectable beams to allow insertion of the center conductor therethrough.

As may be appreciated, quiet often during use and handling, and especially where the connector may be subject to temperature variations during use, the spring engagement between the cantilevered fingers and the center conductor may not be maintained consistently. Moreover, variations in the size of the components used may result in inconsistent contact engagement with the center conductor.

It is, therefore desirable to provide a pin terminal assembly which provides an increase in engagement force between the contacts supported in the pin terminal and the inserted center conductor.

SUMMARY OF THE INVENTION

The present invention provides a terminal assembly for terminating a center conductor of a coaxial cable. The terminal assembly includes a terminal body having a pin at one end and a central cavity at the other end. The central cavity accommodates the center conductor therein. The contact member is supported within the central cavity. The contact member includes a plurality of inwardly directed cantilevered beams extending from a central base. The beams are designed for deflectable electrical engagement with the inserted center conductor. The terminal body includes an inwardly directed shoulder for engagement with the beams at a location between the base and the distal ends thereof. The location defines a deflection fulcrum for the beams at a position distal of the base so as to provide increased contact engagement force between the beams and the center conductor.

The present invention further provides a coaxial cable connector including a terminal assembly as described above.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention provides a pin terminal for terminating the center conductor of a coaxial cable which provides increased contact resistance between the center conductor and the pin terminal so as to assure mechanical and electrical engagement therebetween over time and temperature variations.

Referring now toFIGS. 1 and 2, terminal assembly10of the present invention includes a pin terminal12and a electrical contact14. Pin terminal12is an elongate electrically conductive member typically formed of a suitable metallic material. Pin terminal12includes an elongate forward pin portion16extending to a distal pointed tip18and a rearwardly directed body portion20having an elongate central cavity22formed therein. Cavity22opens at the opposed distal end24so as to insertably accommodate a center conductor30of a conventional coaxial cable50FIG. 4. The center conductor30, which is also formed of an electrically conductive metal is, as will be described in further detail hereinbelow, is insertably accommodated within the cavity22of terminal12so as be in mechanical and electrical engagement therewith.

As shown inFIG. 2, the cavity22formed in body20of pin terminal12includes a first cavity portion32formed adjacent open end24having a first diameter D1. The cavity32has a second portion34longitudinally adjacent portion32having a diameter D2which is less than D1. At the transition between portion32and portion34, terminal body20defines an inwardly tapering annular shoulder36thereat.

Contact14includes an annular contact base40which may be a split ring and a plurality of cantilevered fingers or beams42extending from base40. In the present embodiment, four circumferentially spaced beams42extend from base40. Beams42are elongate members having a proximal end44attached to base40and an opposed distal end46. The beams42are generally form cantilevered springs which are deflectable about proximal portion44at base40. The beams42are deflectable so as to accommodate the insertion of center conductor30therethrough. At rest, the beams extend diametrically inwardly from base40so that the distal extents46are spaced apart a distance less than the diameter of the center conductor30so as to allow the distal extents46to mechanically and electrically engage the inserted center conductor. The deflection of the beams permit such insertion.

Over time during use and with various temperature fluctuations and due to variations in the diameter of the center conductor, the length of beams42and the'spring deflection thereof may result in insufficient contact resistance being established between the distal extents46and the center conductor30. In order to assure an adequate contact resistance force being applied by the beams to the center conductor, the pin terminal12employs shoulders36to shorten the deflectable cantilevered length of beams42. The shoulder36defines a location for engagement with the beams at a position between the distal extents46and the base44. This location defines a deflection fulcrum closer to the distal extents46of the beams to thereby shorten the deflectable beam length and thereby limit deflection thereof. This provides increased contact resistance engagement with the inserted center conductor.

The distal extents46of beams42thereby provide points of higher surface pressure against the center conductor30so as to retain the center conductor30in mechanical and electrical engagement with the contact14thereby establishing and maintaining electrical continuity between the center conductor and the pin terminal12.

Referring now toFIG. 3, a preferred embodiment of the pin terminal assembly of the present invention is shown. Pin terminal assembly10′ is substantially similar to pin terminal assembly10shown and described above. The pin terminal assembly includes a pin terminal12′ and electrical contact14′. In the present illustrative embodiment, pin terminal12includes a right angle pin portion16′ which extends perpendicular to body portion20′. A cavity22′ is formed in the lower end of body portion20′. The cavity22′ is designed for insertable accommodation of a center conductor of a conventional coaxial cable. Cavity22′ is constructed as substantially described above with respect to the embodiment ofFIG. 1and includes an annular shoulder36′ for engagement with contact14′.

Contact14′ includes a base40and a plurality of cantilevered fingers or beams42′ extending from the base40′. In the present illustrative embodiment, the beams42′ provide a curved inwardly directed contact portions47′ adjacent the distal extent46′ thereof. The contact location47′ defines a narrow diameter for engagement with the conductor inserted therein. This narrow diameter assures engagement with inserted conductors of different diameter.

As shown additionally inFIG. 4, the pin terminal assembly10′ of tile type described above is shown supported in a coaxial connector60. Coaxial connector60is a right angle connector supporting a terminal assembly10′. It can be appreciated, however, that other configurations of coaxial connectors and, therefore, other configurations of the terminal pin assembly may be employed within the contemplation of the present invention. Connector60includes a connector body62having a cable receiving end62a. A locking sleeve64is insertable into the cable receiving end62ato secure a coaxial cable therein. The body62of connector60includes the right angle configuration.

The pin terminal assembly10′ is shown accommodating the center conductor30of coaxial cable50. Coaxial cable50is shown prepared as described above having a forward portion of the cable jacket52removed therefrom and an end portion54of the outer conductor folded back thereover. An end portion of the dielectric covering56is removed exposing the distal end of center conductor30. The prepared coaxial cable50is inserted into the connector body62of the coaxial connector60so that the center conductor enters the cavity22′ of pin terminal12′. Interconnection between the center conductor30and the pin terminal12′ is achieved as above described.

As shown inFIGS. 3 and 4, the contact location47′ between each proximal beam42′ and distal extent46′ makes electrical engagement with conductor30. The shoulder36′ maintains the contact portion47′ in mechanical and electrical engagement with center conductor30. In a manner described above, shoulder36′ serves as a fulcrum to prevent over expansion of the beams42′ as they deflect about proximal portion44′ and to maintain the contact portion47′ in engagement with the center conductor30. Placement of the shoulder36′ at a location closer to the distal end46′ of the beams shortens the deflectable beam length and limits differentiation thereof to assure adequate electrical engagement between the center conductor30and the contact beams42′.

Once the cable50is properly positioned within connector body62, locking sleeve64may be moved forward into connector body62to lock the cable50in place. Coaxial cable60with the coaxial cable50terminated thereto may be used in conventional fashion with the electrical contact14′ supported within pin terminal10′ maintaining electrical and mechanical engagement with the center conductor30throughout use.

Various changes to the foregoing described and shown structures would now be evident to those skilled in the art. Accordingly, the particularly disclosed scope of the invention is set forth in the following claims.