Technical Field
The present invention relates generally to electrical connectors. More particularly, the present invention relates to an electrical connector for coupling to an insulated electrical coaxial cable or wire. Specifically, the present invention relates to an electrical connector which is coupled to an insulated coaxial cable without being required to strip the insulation from the end of the insulated coaxial cable.
Background of the Invention
In the past, a wide variety of electrical wire connectors have been provided for connecting to wire ends. In a typical connector, the end of the wire is stripped of insulation and the bare wire is inserted into a connector where it can be soldered or clamped or otherwise attached to the connector. It is also common to tin the wire ends by coating the wire end with solder and a wide variety of connectors have been provided which removably hold the wire to the connector.
Typical connectors are seen in audio systems, such as hi-fi speakers, in which a wire end is stripped of the insulation and is inserted in an opening and a threaded nut is threaded down onto the wire. The nut can be loosened for removing the wire. Other audio speakers include spring clamps which allow a wire end to be stripped of insulation and inserted into an opening while lifting the spring connector clamp and then releasing the spring connector clamp onto the wire. Other commonly used connectors allow a stripped wire end to be inserted into a connector or into both ends of a connector and then clamped with pliers to collapse a conductive sleeve onto the wire. This type of connector is made of a malleable metal such that collapsing the connector onto the stripped wire end provides the necessary electrical contact. The environment in which the connector is used will determine if the exterior of the connector will need to be insulated.
In contrast to these various types of wire connectors, the present invention deals with a wire connector that does not require the insulation to be stripped and also provides, in some embodiments, for the insertion of the insulated wire end in a manner to lock the wire end in place inside the bore of a wire connector.
Prior wire connectors can be seen in the following U.S. patents. The Chang U.S. Pat. No. 4,013,333 for a wire connector having two concentric sockets adapted to be assembled one into the other and in which the inner socket has a conductive needle mounted therein for sliding a wire end into each end of the connector and which also uses a spike pressed in two holes in the sleeves to penetrate the coating of the wire ends.
In the Danner U.S. Pat. No. 3,860,320, a dangler cathode cable assembly is connected to a ball-like cathode member by stripping the end portion of the cable and inserting the end portion into a sleeve which is pressed into an undersized tapered socket that has a pointed pin therein.
In the Friedhelm U.S. Pat. No. 4,786,760, a cable connector for a piezoelectric cable has an insulated cable end which is inserted into a sleeve.
In the Berman U.S. Pat. No. 4,091,233, an electrical cable to the connector is provided for connecting one or more insulated electrical cords or cables together. The insulated cable ends can be inserted into the receptacles on either end and onto a prong of electrically conductive material so that the prong is an electrical contact with the wire of an insulated cord end. A container of adhesive material on the end of the receptacle is released from the container to create a physical bond between the cord and the connector to hold the cord within the connector.
In my prior U.S. Pat. No. 5,403,201, an electrical connector is coupled to an insulated electrical conductor without striping the end of the insulated conductor. The insulated wire is held with a spring clamp which allows the wire to be released.
U.S. patents directed to other structural arrangements for electrical connectors are exemplified, for example, by the Homolka U.S. Pat. No. 5,052,946, directed to a plug connector for a high voltage coaxial cable which uses a plug in contact for the connection with the central conductor. In the Komada U.S. Pat. No. 4,352,240, a method of connecting a coaxial cable to an electrical connector is provided which drives a pin shaped positive terminal into the center conductor. The Gerhard U.S. Pat. No. 3,444,507 is for an electrical connector for semi-solid conductors; the Caulkins U.S. Pat. No. 3,951,503 is a cable splice assembly for multiconductor cables; and the W. C. Gourley et al. U.S. Pat. No. 3,317,883 is for a high voltage wire coupling having a pair of prongs for coupling to the center conductor of insulated wires.
The present invention utilizes an electrical connector for coupling to an insulated electrical coaxial cable end wherein the coaxial cable is inserted into a bore in the connector housing so as to drive a prong located therein into the cable end. The cable is then releasably clamped through the insulation of the cable with conductive clamps which extend into the conductive sheath to thereby form a coupling to the center conductor and separately to the conductive sheaf.
Summary of the Invention
It is a primary object of the present invention to provide an improved coaxial cable connector.
In one aspect of the invention, the improved coaxial cable connector has a housing with a central bore and a center wall separating two ends of the bore into opposing first and second chambers.
In another aspect of the invention, the improved coaxial cable connector includes a center electrical conductor extending through the wall of the housing into both chambers of the bore. The central conductor has a conducting stem with a pointed end extending axially into the first chamber for making electrical contact with the center conductor of a coaxial cable and a cylindrical portion extending axially into the second chamber.
In another aspect of the invention, the improved coaxial cable connector includes electrical conductive arms which extend axially from the housing at the end of the first chamber. The arms each terminate in pointed ends which are pointed radially and are adapted to pierce the outer insulation of a coaxial cable and to make electrical contact with the conductive sheath thereunder.
In still another aspect of the invention, the improved coaxial cable connector includes a closure member for attachment to the housing at the end of the first chamber and which overlies the conductive arms to enforce electrical contact with the conductive sheath at the pointed ends.
In a further aspect of the invention, the closure member may be a cover secured to the housing by threading engagement or by an interference fit or snap fit as may be convenient and includes a frusto-conical inner surface which engages the conductive arms and urges the pointed ends to pierce the outer insulation and engage the conductive sheath of the coaxial cable.
In a further aspect of the invention, the closure member may be a heat shrinkable sleeve which grips the housing and overlies the conductive arms and coaxial cable to enforce piercing of the outer insulation of the coaxial cable by the conductive arms when subject to a requisite heat shrink temperature.
In a further aspect of the invention, a coaxial cable with a central conductor and a concentric insulator overlaid by a concentric conductive sheath and an outer insulation is inserted through the closure member and into the first chamber of the housing and forced onto and over the pointed end of the central conductor so as to establish electrical conductive contact therebetween. The pointed end of the conductive arm is pressed into piercing engagement with the outer insulation of the coaxial cable to make electrical conductive contact with the conductive sheath thereunder, and the closure member is secured to the housing so as to enforce the conductive contact of the conductive arm with the conductive sheath of the coaxial cable.
In still a further aspect of the invention, a coaxial cable with a central conductor and a concentric insulator overlaid by a concentric conductive sheath and an outer insulation is inserted through the aperture into the cap and into the first chamber of the housing and forced onto and over the pointed end of the central conductor so as to establish electrical conductive contact therebetween, and the cap is installed onto the housing to engage the conductive arms and to force piercing of the outer insulation and to make electrical contact at the pointed ends of the concentric conductive sheath of the cable.
These and other objects of the invention as well as the advantages thereof over existing and prior art forms, which will be apparent in view of the following detailed specification, are accomplished by means hereinafter described an claimed.
In general, a novel electrical connector embodying the concepts of the present invention is intended for coupling to a coaxial cable having a central conductor, an adjacent concentric insulator, a generally concentric outer conductive sheath, and an outer insulation enclosing the conductive sheath.
In one embodiment of the invention, the connector is made up of a housing having a central bore, an electrically conductive pin that is disposed in the bore, one or more conductive arms which extend axially from one end of the housing and an aperture housing cap that receives the coaxial cable and cooperates with the conductive arms, the cable and the one end of the housing to establish electrical contact with the central conductor and conductive sheath of the cable and to maintain the cable in position in the connector.
The housing is electrically conductive and includes an electrically insulating annular wall which separates the bore into oppositely disposed first and second chambers.
The electrically conductive pin is mounted in the annular wall. The pin has one pointed end protruding axially from the wall into the first chamber of the housing bore and an opposite end extending from the wall in the opposite direction into the second chamber.
One or more conductive arms are electrically connected to and extend axially from the periphery of the housing at the end of the first chamber. The arms have pointed ends sized to be driven through the outer insulation and into the conductive sheath of the coaxial cable without contacting the center conductor.
The housing cap includes an aperture for receiving a coaxial cable therethrough and is desired to be secured to the end of the hosing at the first chamber by threading a snap fit, a force fit, or an equivalent means. The interior surface of the cap may also have a frusto-conical wedging surface for driving and holding the conductive pointed ends through the outer insulation and into electrical contact with the conductive sheath of the cable. The frusto-conical wedging surface also forces the clamps into frictional engagement with the outer insulation to assist the pointed ends in holding the coaxial cable within the connector.
In practice, the coaxial cable is threaded through the housing cap and inserted into the first chamber of the housing. The cable is driven onto the pointed end of the pin in the chamber thereby establishing electrical contact between the pin and the center conductor of the cable. Thereupon the conductive arms are clamped onto the coaxial cable so as to make their pointed ends pierce the insulation cover and to make engagement with the conductive sheath thereunder. The clamping may be accomplished manually by hand or with a tool, or by relying upon the welding action of the frusto-conical surface of the housing cap against the conductive arms of the cap secured to the housing. A second embodiment of the invention replaces the housing cap with a heat shrinkable insulation.
One preferred embodiment of a connector in accordance with the invention that illustrates the best mode contemplated for putting it in practice is described herein with reference to the annexed drawings that form a part of the specification. However, this description does not attempt to show all of the forms and modifications in which the invention might be embodied. As such, the embodiment shown and described herein is illustrative and can be modified without departing from the spirit and scope of the invention particularly as set forth in the claims that form a part hereof.
Brief Description of the Drawings
FIG. 1 is an exploded view of an electrical connector and a portion of a coaxial cable in accordance with the present invention;
FIG. 2 is an exploded view of the electrical connector of FIG. 1 but looking in the opposite direction and having the coaxial cable inserted into the housing cap which has been sectioned for clarity;
FIG. 3 is a sectional exploded view of the electrical connector of FIGS. 1 and 2;
FIG. 4 is a sectional view of the electrical connector having a coaxial cable end attached thereto;
FIG. 5 is a perspective view of another embodiment of a coaxial cable connector in accordance with the present invention;
FIG. 6 is an exploded sectional view of the connection of FIG. 5; and
FIG. 7 is a sectional view of the embodiment of FIGS. 5 and 6 having the cable attached thereto.
Description of an Exemplary Embodiment
Referring to FIGS. 1-4 of the drawings, an electrical connector 10 in accordance with the invention, especially adapted for use with a coaxial cable 11, is illustrated. The coaxial cable 11 has circumferentially disposed components including: a center conductor 12, a concentric insulation 13 surrounding the center conductor 12; a concentric conductive wire braid or sheath 14 surrounding the insulation 13; and an outer insulation 15 covering the conductive sheath 14. The connector 10 can connect various types and sizes of coaxial cables to a variety of plugs, jacks, and connectors, all referred to herein as electrical connectors, and as illustrated here, the connector 10 of the male part of 75 ohm coaxial F-connector. Connection of the coaxial cable 11 to the connector 10 is accomplished without solder and without the need to strip the insulation cover 15 from the cable.
The coaxial cable 11 as connected to an electrical apparatus, such as a television set, requires that the center conductor 12 and the outer sheath 14 be electrically coupled separately and insulated from one another to another connector. In accomplishing that purpose, the connector 10 includes a connector housing 16 having a cylindrical cable attaching portion 17 with external threads 18 defining a first chamber 20 and a cylindrical housing portion 25 with internal threads 26 defining a second chamber 24.
An electrically conductive pin 19 is mounted to an insulation base 22 within the housing 25 with the base 22 abutting and being secured to a wall portion 25A. The conductive pin 19 has a tapered prong 21 extending axially into the bore defining the first chamber 20 and also has a cylindrical prong 23 extending axially into the bore defining the second chamber 24. Electrically conductive arms 27 extend axially from the cable attaching portion 17 of the housing 16. Each arm has pointed contacts 28 which are also electrically conductive. A plurality of clamping arms 27 are contemplated but a single arm can perform the operation of attaching the coaxial cable 11. A locking cover 30 is a generally cylindrical conductive member having internal threads 31 adapted to engage the external threads 18 of the connector body portion 17. The cap 30 has a central bore to receive the coaxial cable and an annular, frusto-conically angled wedging portion 32 formed therein. FIG. 3 also shows a cup-shaped insulation covering 29 received within the connector housing 16 which provides extra security against contact of the conductive sheath 14 with the connector body 16 metal portions in the event a stray strand of wire from conductive sheath 14 should extend from the cable 11.
In operation, the tip of the coaxial cable 11 does not have any of the insulation stripped from the conductors 12 or 14 as is normally required to connect a coaxial cable to a connector. The undisturbed end of the coaxial cable 11 is slidably inserted between the clamping members 27 and into the bore 20. Sufficient force is provided to push the cable 11 onto the prong 21 and into electrical contact with the center conductor 12. The electrical conductive contact with the coupling stem portion 19 provides electrical continuity to the probe 23. The connector 10 can then be attached to an electrical apparatus, such as a television set or the like, or to another coaxial cable.
Once the coaxial cable 11 is pushed into the bore and attached into electrical contact with the prong 21, the ends of the arms 27 may be clamped to drive the pointed contacts 28 through the outer insulation 15 into the conductive sheath 14. This may be accomplished manually, by hand or with pliers, in clamping the ends of the arms 27 to force the pointed contacts 28 through the outer insulaitno 15 of the coaxial cable 11 into the concentric conductive sheath 14 to make an electrical contact therewith. Alternatively, and in carrying out the same function, the ends of the arms 27 may be clamped by installing the housing cap 30 onto the threads 18 of the housing portion 17 so that wedging portion 32 drives against the ends of the clamps to drive the pointed contacts 28 through the outer insulation 15 and into the conductive sheath 14. If done manually, the next step is to maintain the cable and the arms 27 in contact by threading the cap into place or utilizing the heat shrink embodiment, as shown in FIGS. 5, 6 and 7.
Turning now to FIGS. 5, 6 and 7, another embodiment of a coaxial cable connector is illustrated in which an electrical connector 35 has an electrically conducting connector body 36. In FIG. 7, the connector 35 has a coaxial cable 11 attached to one end thereof. The other end of the connector 35 has internal threads 27 with a center conductor 39 having a cylindrical conductor portion 38. In this embodiment, a heat shrinkable insulating sleeve 40 is attached to the conductive connector housing portion 41. A pointed prong 43 on the stem 39 is disposed in a chamber 42. The pointed prong 43 is provided for insertion into electrical contact with the center conductor 12 of a coaxial cable 11. A plurality of clamping arms 44 are connected to the conductive housing 41 and each arm 44 has a pointed prong 45 extending radially inward form the end thereof.
Coaxial cable 11 has electrical insulation 13 around the center conductor 12 which is covered by the concentric conductive sheath 14 which in turn is wrapped in insulation cover 15. In operation, the coaxial cable 11 end is inserted into an opening 46 in the insulation 40 between the clamping arms 44 and prongs 45. The prong 43 is driven into or continuously adjacent the center conductor 12 thereby making electrical contact therewith.
The center conductor 12 on coaxial cable is sometimes a single conductor wire and sometimes is formed of multiple stands so that the prong 43 will sometimes be driven into the multiple strand wire and at other times be directed adjacent to the single wire conductor 12.
Once the cable 11 is inserted and is in conductive contact with the prong, the arms 44 are clamped manually by hand or with a tool so as to cause the pointed prongs 45 to pierce the outer insulation 15 and make conductive contact with the conductive sheath 14. Alternatively, the heat shrinkable insulation 40 is heated which causes it to shrink tightly onto the housing 41 on onto the cable 11 and the arms 44. This shrinkage can push the pointed prongs 45 of arms 44 through the outer cover 15 and into electrical contact with the conductor member 14. In the case of the alternative and to further assure proper contact, the insulation 40 can be pressed by the assembler onto the clamp members 44 to set the prongs 45 through the insulation 15 and into the conductor 14. The insulating sleeve 40 thus holds the connector 35 to the cable 11 while forming an insulation for the tip of the cable. The arms 44 also lock into the cover 15 to hold the cable in place with the conductive prong 43 making contact with the conductor 12 of the cable 11. This provides the center conductor 38 with a contact with the cable 11. The prongs 38 and 43 are mounted to an insulating member 47 which is attached to a wall 36A of the body 36.
While only two preferred embodiments of my present invention are disclosed, it is to be clearly understood that an improved electrical connector for a coax cable has been provided. The structure advantageously allows the coaxial cable to be attached to the connector without stripping or removing any of the insulation on the ends of the cable while providing a complete electrical connection to the center conductor and the conductive ground sheath. The concepts of the present invention are susceptible to numerous changes which will, in view of the foregoing disclosure, become apparent to one skilled in the art. Therefore, the scope of the present invention is not to be limited to the details shown and described but is intended to include all changes and modifications which come within the scope of the appended claims.