Plug connector

A plug connector for use with coaxial cable having a central signal wire in which a base member has a bore defined by a side wall adapted to receive the end of a coaxial cable. A member having a pointed end extends into the bore and is adapted to extend into the coaxial cable in contact with the central signal wire. A threaded bore extends through the side wall of the base member and a threaded screw member is mounted in the threaded bore. The screw member is adapted to be driven into the side of the coaxial cable. The screw member has a head portion at one end and a knife edge at the other end, the end having the knife edge having a pocket therein to receive the material of the coaxial cable cut by the knife edge.

FIELD OF INVENTION

This invention relates generally to electrical plug connectors, and more particularly to electrical plug connectors for connecting coaxial cable to electrical devices.

BACKGROUND

Many types of electrical connectors are known. Examples of such connectors are shown in U.S. Pat. Nos. 6,533,617, 6,568,964 and 6,729,912 to D'Addario. The disclosure of each of these patents is incorporated herein by reference in its entirety. The connectors as shown in those patents include a base into which a coaxial connector is inserted. This connector also includes a central probe member which is in electrical contact with the central signal wire of the coaxial cable. As shown in these patents, a set screw or other type of screw is used to secure the coaxial cable within the base of the connector. The set screw is tightened against the outer coating or jacket of the coaxial cable and penetrates the cable.

In some types of coaxial cables, especially those that are known as plenum cable, the outer coating or jacket is relatively tough with the result that a typical screw, when fully tightened, does not penetrate the outer jacket. This results in the possibility of the cable being able to be inadvertently pulled out or dislodged from the connector base, interrupting the electric connection. Accordingly, there exists a need for a connector wherein the connecting screw is effective to prevent withdrawal of the cable from the connector.

SUMMARY OF THE INVENTION

These deficiencies are overcome by a connector having a screw with a sharp edge for cutting the outer jacket of the cable and a pocket associated with the sharp edge for encapsulating the cut region of the jacket.

According to one aspect there is provided a plug connector for use with a coaxial cable having a central signal wire. The connector comprises a body or base member having a bore therein defined by a sidewall adapted to receive the end of a coaxial cable. A central signal probe, pin or other conducting member is provided in the body or base, having one end in the bore to engage the central signal wire of the coaxial cable. A threaded bore extends transversely through the sidewall. A threaded screw member is mounted in the transverse bore and adapted to be driven into the side of a coaxial cable. The screw has a head portion at one end and a knife edge with associated counter bore or similar pocket at the other end.

According to another aspect there is provided an assembled plug connector and coaxial cable comprising a body or base member having a bore therein defined by a sidewall. A coaxial cable having an outer jacket, a conductive ground layer, a central signal wire and an insulating layer between the ground layer and the central signal wire, has one end received within the bore. A central signal probe member is provided in the body or base, having one end that engages the central signal wire of the coaxial cable. A threaded bore extends through the sidewall and a threaded screw member is mounted in the threaded bore into the side of the coaxial cable. The screw member has a head portion at one end and a knife edge with associated counter bore or similar pocket at the other end. With the screw fully advanced, the edges contact the ground layer and the pocket at least partially encapsulates a region of the cable jacket within the edges.

DETAILED DESCRIPTION

Referring to the drawings and in particularFIG. 1, a connector10is shown which is of the type generally shown and described in U.S. Pat. No. 6,729,912. Reference should be made to that patent for a detailed description of its construction. However, in general, the connector10includes a base12and an insulating ring14interposed between a conducting ground sleeve16and a conductive signal probe member18. The conducting ground sleeve16is preferably formed from two mating half shells16a and16b that extend from the base and are disposed annularly about the probe member18in substantially coaxial relation. The insulating ring14is preferably comprised of a molded plastic material such as a molded thermoplastic, e.g. acetyl resin, nylon, ABS resin and or blends thereof. The conducting ground sleeve16is composed of a conductive material and may be formed from sheet stock and is disposed coaxially about the insulating ring14.

A pin or probe member18extends from the base10along a central axis and includes a conductive body20having a rounded head22at the free end thereof and the short needle-like portion24at the other end thereof which extends into the base10. The ground sleeve16includes tabs26which extend into recesses28in the base10. The ground sleeve16also includes a plurality of circumferentially spaced apart spring fingers30which are adapted to provide an inward force against a collar of a jack connector (not shown) when the plug connector10is installed on a jack connector.

The base10includes an axial bore32in which a coaxial cable34is received. The inner surface36of the insulating ring14is coextensive with the bore32as shown. A radially extending threaded through bore38is provided in the wall40of the bore32and has a counterbore42. A threaded screw member44is received within the threaded bore38and includes an externally accessible head portion46that is adapted to be tightened against the bottom of the counterbore42. A radial bore47is provided in the internal surface of the wall40of the bore32in the base12. The radial bore47is directly opposite the threaded bore38and coaxial therewith as shown.

The insulating ring14is secured within the conductive ground sleeve16by protrusions50that extend through the sleeve16and retain the sleeve16in place when the base10is secured over the sleeve16and insulating ring14. A ring (not shown) may be positioned about the base12to cover the tabs26and recesses28.

Referring especially toFIGS. 2 and 3, the enlarged head portion46of the screw member44presents a flat surface52that engages the bottom of the counter bore42when the screw member44is fully driven into the base12. The free end54of the screw member44has a bore56therein that forms a pocket58in the free end54of the screw member44. The free end54of the screw member44also has a forwardly and inwardly tapering portion60, which together with the wall of the bore56results in the formation of a knife edge62at the very tip of the screw member44. The pocket58in the free end54of the screw member44has a volume sufficient to contain the material of the coaxial conducting cable cut by the knife edge62of the screw member44as it is being tightened without putting an actual strain on the cable34.

In operation, with the screw member44retracted so that its free end54is withdrawn past the inside surface of the wall40of the bore32of the base12, the coaxial cable34may be inserted into the bore32. The coaxial cable34may be of the conventional type and include a central signal wire64surrounded by an insulation layer66with a ground braid interposed68between the insulation layer66and an outer jacket70.

The coaxial cable34is pushed fully into the bore32so that the needle-like portion24of the probe18penetrates the cable34and makes contact with the central signal wire64of the coaxial cable34. At this point, the screw member44may be advanced within the bore38so that the knife edge62cuts through the outer jacket70and ground braid68into the insulating layer66of the cable34as shown inFIG. 1. The head46of the screw member44in cooperation with the counter bore46controls the depth of penetration of the knife edge62into the coaxial cable34. The depth of the counter bore46and length of the screw member44are so dimensioned and configured as to permit penetration of the forward edge62of the screw member44through the outer jacket70and ground braid68of the coaxial cable34into the insulating layer66, but stopping short of the central signal wire64when the head46abuts the counterbore42.

The pocket58in the screw member is of a depth sufficient so that when the screw is fully tightened and penetrates into the coaxial cable in the position shown inFIG. 1, the pocket58will contain the material of the coaxial cable cut by the knife edge62of the screw member44as it is being tightened without putting any actual strain on the cable. In other words, the depth of the pocket56is greater than the thickness of the cable34that is penetrated by the knife edge62, thereby providing a space74above the outer jacket70and bottom of the bore56in the screw member44as shown inFIG. 1. This arrangement allows the material cut by the knife edge62to rise and be fully contained within the pocket58of the screw member. As the screw member44is tightened and driven into the coaxial cable34, the force exerted on the cable34by the screw member44distorts the cable34causing a portion of the cable jacket70to extrude into the bore47in the internal surface of the wall40of the base20. This provides strain relief for the cable34and mitigates any axial movement of the cable34which could cause the electrical connection to fail.

In the case of the particular connector10shown, the screw member44provides an electrical path from the ground braid68of the coaxial cable34through the base10to the ground sleeve16.

It can thus be appreciated that in the in the preferred embodiment, the base member has a radial bore in the internal surface of its side wall opposite to and coaxial with the threaded bore, the end of the screw having the knife edge has a substantially cylindrical pocket centered on the screw centerline and a frustoconical outer surface that tapers toward the centerline, thereby forming a circular knife edge at the diameter of the pocket, and the screw has been advanced sufficiently so that the region of the cable enclosed by the pocket is severed from the remainder of the cable and some of the cable jacket is extruded into the opposite bore.

While the arrangement of the screw member44and base12was described in connection with one particular type of end connector, it is understood that this was for illustration purposes and the use of the base12and particular screw member44construction for connection to a coaxial cable can be used with other types of end connectors such as other designs of RCA connectors and various types of RF connectors, such as BNC and F connections, as well as both male and female types. Furthermore, the invention may be used with any type of conductive connection between the inner end of the signal probe18and the central signal wire64of the cable.