Quick Connection Coaxial Cable Connector

Abstract

A quick connection connector for a coaxial cable consists of a body having a cylindrical portion with a well therein in which a squared off end of the cable is received against a stop in the well. With cable end thus received in the well, the outer conductor or sheath of the cable is in electrical contact with the stop, and a spring-loaded pin contact in the well makes contact with the end of the cable's center conductor. Clamp means on the connector is adapted to hold the cable end in the well.

Description

The present invention is an electrical connector for a coaxial cable. In particular it is a connector adapted for making a temporary connection simple and quickly, for test purposes, for example.

Coaxial cables have a center conductor coaxially supported within a tubular conductor, which is usually the outer sheath of the cable, the support being provided by suitable insulating or dielectric material packed between the conductors.

PRIOR ART

In conventional connectors the center contact for the center conductor of the cable usually has a split tubular portion into which the center conductor of the cable is inserted to be held in place by friction. For this purpose a portion of the center conductor at the end of the cable must be uncovered and exposed for about half an inch or so by removing the surrounding sheath and insulation, which is a time consuming and costly operation. Moreover, for this type of contact the exact length of the portion of the center conductor which is exposed for insertion in the split tubular contact is usually critical for maintaining good electrical matching at high frequencies. That is, the length of the center conductor exposed for making the connection is critical for maintaining the impedance characteristics of the cable through this type of connector. Also, one particular problem with this type of connector is that the contact is easily distorted by misalignment of the center conductor or by burrs on the end of the center conductor caused when inserting the center conductor in the split tubular contact or during removal of the surrounding sheath and insulation.

OBJECTS

A principal object of the present invention is to provide a connector with which a connection is made simply and quickly, which does not require special preparation of the cable end--other than to cut the end square so that its end face is at right angles to the axis of the cable--and which is adapted to preserve the impedance characteristics of the cable through the connection.

SUMMARY OF THE INVENTION

In accordance with the invention the connector body has a well in which the squared-off end of the cable is received. The center contact of the connector is a spring-loaded pin which bears against the end of the center conductor of the cable when the cable end is against a stop in the well, and the cable end is held in position in the well by suitable clamp means.

THE DRAWINGS

Further objects, advantages and features of the connector of this invention appear in the following description of an illustrative embodiment shown in the accompanying drawings in which:

FIG. 1 is a cross-sectional view longitudinally through a connector of this invention showing a cable end through the sleeve portion of the connector prior to connecting the sleeve and cable to the body portion; and

FIG. 2 is a side elevational view, partly in section, of the connector and cable shown in FIG. 1.

Detailed Description

A connector 10 of this invention comprises a body 11 and a sleeve 12 adapted to be screwed onto a cylindrical portion 13 at one end of the body for connecting a coaxial cable 14 to another cable or to a test lead (not shown). At its other (left) end the connector 10 is adapted to be connected by suitable connecting means to another cable, test lead or the like. In FIG. 1 connecting means at the left-hand end is illustrated by a conventional type N male socket (not shown) on the end of said other cable or test lead, but a UHF fitting or other conventional, or otherwise suitable, connecting means could be used on this end, the invention being directed to the connecting means at the right-hand end of the connector 10 as viewed in the drawings.

A coaxial cable 14 with which the connector 10 is adapted to be used has a center conductor 16 coaxially supported within a tubular outer conductor 17 by insulation 18. In the type of coaxial cable shown, with which the connector 10 is particularly adapted to be used, the outer conductor 17 is formed from a metal tube.

The cable 14 is prepared for connection by the connector 10 by squaring off its free end 19 so that the end face is at right angles to its axis.

The sleeve 12 has a bore 20 through which the cable 14 is slidably received and the cylindrical portion 13 of the body 11 has a well 21 therein into which the free end 19 of the cable is inserted. One end of the bore 20 of the sleeve is interiorly screw threaded at 22 to mate with an exterior screw thread 23 on the cylindrical portion 13 for screwing the sleeve onto the body 11.

When the free end 19 of the cable is inserted in the well 21 the end of the outer conductor or sheath 17 abuts a stop which is suitably in the form of an annular shoulder 24 in the well, and a spring loaded contact pin 25 mounted in the body 11 to extend into the well 21 presses into contact with the end of the center conductor 16 under the pressure of a spring 26. The contact pin 25, which is made of conductive material, is slidable in one end of a tube 27 of conductive material which is supported longitudinally through the center cavity 11a of the body 11 by insulation 28 packed between the tube 27 and the outer shell of the body. A conductive contact pin 15a, which is the center contact of the male socket 15 at the left-hand end of body 11 is force fitted into the other end of the tube 27 so as to be fixed therein. Thus, the tube 27 in conjunction with the contact pins 15a and 25 provide a central conducting path through the body 11 from the center conductor 16 when the cable end 19 is seated against the annular shoulder 24 in the well 21.

The spring 26 is in the center of the tube 27 between the inner ends of the contact pins 15a and 25, with one end backed up against the fixed pin 15a and its other end engaging the inward end of the slidable contact pin 25. The right-hand end portion of the tube 27 in which the slidable pin 25 is supported has longitudinal slits 27a dividing the end of the tube into fingerlike segments. The tube is made of hard springy material, such as spring brass or beryllium copper, and the segments defined by the slits are bent slightly inward to grip the pin 25 with sufficient pressure to retain the pin in the tube while permitting the pin to slide inward against the tension of the spring 26 when pushed in, by insertion of a cable end in the well 21, and to be moved outward by the spring 26 to a normal position, determined by the length of the spring, when inward pressure on the pin is released.

The pin 25 is made of a hard conductive material, such as silver-plated steel or beryllium copper in order to withstand the abuse of numerous temporary contacts of the central conductors 16 of successive cable ends inserted in the well 21. Also, the outward end of the pin 25 may be bevelled around its circumference as shown, or otherwise shaped, to minimize damage to the end of the pin, or the making of a faulty contact with the end of a central conductor 16.

The shell of the body 11, including the cylindrical portion 13 and the shoulder 24 are of conductive material and the shoulder 24 is in position to be engaged by the annular face end of the outer conductor or sheath 17 of the cable 14 when the cable end 19 is seated in the well 25 so as to provide a conductive path from the outer conductor 17 through the body 11 to a cylindrical contact 15b which is in the male socket 15 shown at the left-hand end of the body and which is electrically connected to the shell of the body.

When the sleeve 12 is screwed onto the cylindrical portion 13 of the body and the cable 14 is through the bore 20 of the sleeve with the cable end 19 seated in the well 21, the cable is held in this position by suitable releasable clamping means. As illustrated in the drawings, suitable clamping means is provided by a split-sleeve element 29 carried in an annular recess 30 in the wall of the bore 20.

As best seen in FIG. 2, the split-sleeve element 29 is a sleeve made of spring material, split at 29 a and biased to spring radially outward so as normally to be only loosely in contact with a cable 14 through the bore 20 and thereby permit the cable 14 to slide freely therethrough.

The recess 30 is deeper at the right-hand end to accommodate a cam ring 31 which is mounted in the recess adjacent to the left end of the sleeve element. The cam ring 31 has a cam surface 31a at one side slanting outward and under the adjacent end edge of the sleeve element 29. At the other side the cam ring 31 has an annular face 31b in line to be engaged by, and pushed to the right by, the annular end edge 13a of the cylindrical portion 13 of the body 11 when the sleeve 12 is screwed onto the cylindrical portion. As shown in FIG. 1, the cam surface 31a of the cam ring and the sleeve element 29 are constructed and arranged so that as the cam ring 31 is pushed to the right by the edge 13a of the cylindrical portion, the cam surface 31a pushing against the edge of sleeve element 29 radially compresses the sleeve element 29 to bear against the surface (conductor or sheath 17) of a cable 14 through the bore and thereby hold the cable in fixed position relative to the sleeve. The recess 30 is suitably made slightly longer than the combined lengths of the cam ring 31 and sleeve element 29 That are mounted therein to provide some longitudinal play so that the ring and sleeve element move smoothly and easily into their cable-gripping position without binding.

In a preferred form the sleeve element 23 and cam ring 31 are made of conductive material so that when they are in position with the sleeve element bearing against the outer conductor or sheath 17 of the cable and the cable end 19 is seated in the well 21, the engagement of the cam ring 31 with the end edge 13a of the cylindrical portion 13 provides an additional conductive path from the outer conductor or sheath 17 to the body 11.

In addition, the outside diameter of the tube 27 and the inside diameter of the center cavity 11a in the body 11 are proportioned to provide the correct electrical impedance to match the impedance of the cables to be tested. Thus, the impedance characteristics of the cable 14 are maintained in the connector.

Claims

What we claim is:

1. A quick connection electrical connector for testing of coaxial cable which has a center conductor supported within a tubular sheath, said connector comprising a body having a cylindrical portion with a well therein in which a cable end having its center conductor and tubular sheath cutoff in a single plane at right angles to the axis of the cable is received, stop means in the well against which said cable end abuts, a spring loaded electrically conductive pin supported in the body having a free end extending into the well to resiliently contact the end of said center conductor which is exposed at said cable end, first conducting means by which the pin is supported and to which the pin is electrically connected, a center cavity in the body beyond the stop means, the first conducting means extending through the body including the cavity therein, and being electrically insulated from the body, and releasable clamp means for temporarily holding a cable end in said well.

2. The connector of claim 1 for a coaxial cable of which the sheath is made of conductive material to provide an outer conductor, the outside diameter of the pin support and the inside diameter of the center cavity in the body being proportioned to provide the correct electrical impedance to match the impedance of the cables to be tested, said body including second conducting means, said cylindrical portion of the body being conductive and connected to said second conducting means, and said stop means in said well being an annular shoulder of conductive material integral with said cylindrical portion, and in position for the sheath at said cable end in the well to abut it and thereby complete a conductive path from said sheath to second conducting means.

3. The connector of claim 2 in which said spring-loaded pin is approximately the same diameter as said center conductor of the cable and is supported to contact the end of said center conductor substantially in end to end axial alignment when said cable end is in the well and against said annular shoulder, and in which the radial distance from the pin to the shoulder is approximately the same as the radial distance from the center conductor to the sheath, whereby said pin and said cylindrical portion provide a continuous transmission path to said conducting means, which path is thereby dimensionally adapted to maintain the impedance characteristics of the cable.

4. The connector of claim 1 in which said clamp means comprises a sleeve having a bore therethrough through which the cable is normally slidably received, said sleeve and said cylindrical portion being adapted for one end of the sleeve to be screwed onto the cylindrical portion, a member mounted in the sleeve adjacent to the bore for movement laterally into the bore to bear against the sheath of a cable through the bore, and cam means in the sleeve actuated by movement of the cylindrical portion into the sleeve when the sleeve is screwed onto the cylindrical portion for moving the member into the bore and thereby holding a cable which is through the sleeve in fixed position relative thereto.

5. The connector of claim 4 for a coaxial cable of which the sheath is made of conductive material to provide an outer conductor, said connector including second conducting means through the body, said member being of conductive material, said cylindrical portion of the body being conductive and connected to said second conducting means, and means completing an electrical connection between the member and the cylindrical portion when the sleeve is screwed onto the cylindrical portion, thereby to provide a conductive path from said sheath to said second conducting means when said cable is fixed through the sleeve by said member.

6. The connector of claim 1 in which said body has the center cavity opening into said well, in which said pin is slidably mounted in a tube that is the support for said pin, and including a spring in the tube urging said pin outward into said well.

7. The connector of claim 6 in which the inside diameter of said center cavity and the outside diameter of said tube are proportioned to provide electrical impedance matching the electrical impedance characteristics of a cable that is to be connected to the connector.