Coaxial Cable Connectors

Abstract

Coaxial cable connectors in which a clamping member is carried within a cap member and is arranged to cam wall means of a central conductor, supported within a body member, into engagement with an end portion of a cable center conductor when the cap member is moved in a connecting direction relative to the body member. In one embodiment, a ferrule member within the cap member has a plurality of finger portions cammed by cam means within the cap member into engagement with the outer surface of the cable, an inner wall portion of the ferrule member being fitted within an end portion of the cable outer conductor.

Description

This invention relates to coaxial cable connectors and more particularly to coaxial cable connectors which are readily operable to connect and disconnect the ends of coaxial cable conductors to and from fixed conductors. The connectors are very rugged and durable, highly reliable in operation and economically manufacturable and can be used for repeated connect and disconnect operations.

Although having other applications, the connectors of this invention were specifically designed for use at the end of a coaxial cable to connect the outer cable conductor to a chassis of an amplifier or the like and to connect the center cable conductor to a central conductor insulatingly supported relative to the chassis. Such connectors are commonly required in CATV (community antenna television) systems, for example. Electrical connectors have heretofore been proposed in which a hollow cap member receives the end of a cable and is threaded onto a mating hollow body member which may be mounted on an amplifier chassis. In one type of construction, a split ferrule is provided within the cap member having internal serrations which engage the outer surface of the cable outer conductor while, to hold the cable center conductor, wall portions of a hollow and split central conductor in the body member are cammed inwardly into engagement with the end portion of the cable center conductor by means of a clamping member supported within the body member for axial movement, a coiled compression spring being provided in the body member to urge the clamping member to a released position when the cap member is separated from the body member in a disconnect operation. Such connectors have been generally satisfactory but have been more difficult and expensive to manufacture than would be desirable.

This invention was evolved with the general object of providing improved connectors which overcome disadvantages of prior connectors and which are readily operable, rugged and durable while being economically manufacturable.

Another object of the invention is to provide electrical connectors for use with a coaxial cable which does not require stripping of the cable sheath while at the same time securely holding the cable and providing a reliable ground connection to the cable outer conductor.

According to an important feature of this invention, a central conductor would bend a body member as radially deflectable wall means defining an opening for receiving a cable center conductor and a clamping member is carried by and within a cap member and is arranged to cam the wall means radially inwardly into tight engagement with the end portion of the center conductor when the cap member is moved in a connecting direction, the clamping member being withdrawn by the cap member, when the cap member is moved in a disconnecting direction away from the body member. With this arrangement, the clamping member is positively withdrawn to insure release of the cable center conductor. A compression spring is not required and without it, the electrical performance is improved.

According to a specific feature, the clamping member has a central opening receiving the wall means of the central conductor and defining an inwardly facing surface for camming engagement with the wall means. Preferably, the clamping member and the body member have surface portions interengagable to limit movement of the clamping member in the connecting direction.

According to another specific feature, the clamping and body members have generally cylindrical surface portions in facing relation with a spacing and length such as to prevent canting of the clamping member.

According to another important feature of the invention, a ferrule member is provided within the cap member and has a plurality of resilient finger portions arranged to engage angularly spaced outer surface portions of the cable with cam means being provided with the cap member to cam the finger portions radially inwardly into tight engagement with the cable when the cap member is moved in the connecting directions. Preferably and in accordance with a specific feature, the ferrule member includes an integral inner wall portion arranged to fit within an end portion of the cylindrical outer conductor. With these features, the cable is securely held and an excellent ground connection is obtained while stripping of an outer sheath from the cable is not required.

This invention contemplates other objects, features and advantages which will become more fully apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate preferred embodiments and in which:

FIG. 1 is a side elevational view of a coaxial cable connector constructed in accordance with the principles of this invention;

FIG. 2 is a sectional view on an enlarged scale, taken substantially along line II--II of FIG. 1;

FIG. 3 is a sectional view of a cap member of the connector of FIGS. 1 and 2 and parts therewithin, before assembly;

FIG. 4 is a sectional view of a body member of the connector of FIGS. 1 and 2 and associated parts, before assembly; and

FIG. 5 is an end elevational view, on an enlarged scale, of a ferrule member of the connector of FIGS. 1 and 2.

Reference numeral 10 generally designates a coaxial cable connector constructed in accordance with the principles of this invention. In FIG. 1, the connector 10 is shown in use in connecting the end of a coaxial cable 11 to a chassis, a wall 12 of which is shown, an outer conductor of the cable 11 being electrically connected to the wall 12 and an inner conductor thereof being connected to a conductor 13 insulatingly supported relative to the wall 12.

The illustrated cable 11 comprises a center conductor 14 supported by spacer members 15 of dielectric material within a cylindrical outer conductor 16 with a sheath 17, preferably of a tough plastic material, being disposed around the outer conductor 16.

The connector 10 comprises a cap member 19 and a body member 20, cap member 19 having an internally threaded portion 21 threaded on an externally threaded portion 22 of the body member 20. Body member 20 is secured to the wall 12 by means of a hex nut 23 which is threaded on a reduced diameter externally threaded portion 24 of the body member 20 the wall 12, the wall 12 being clamped between the hex nut 23 and a shoulder 25 of the body member 20. Preferably, an O-ring seal member 26 is disposed on the body member 20 between the shoulder 25 and the threaded portion 24 to sealingly engage between the body member 20 and the inner surface of an opening 27 in the wall 12.

A support member 28 of the dielectric material, preferably polyphenylene oxide, is provided for supporting the center conductor 13 within the body member 20. Preferably, the member 28 has an annular groove 29 in its outer surface which receives an inwardly projecting annular portion 30 of the body member 20 and the center conductor 13 has axially spaced annular grooves 31 which receive inwardly projecting annular portions of the member 28. To minimize any impedance discontinuities, the member 28 is preferably formed with spaced inner and outer tubular portions connected together by relatively thin integral portions 35.

The center conductor 13 has a portion 37 of larger diameter a portion of which is hollow to receive an end portion 38 of the coaxial cable inner conductor 14 and which is slit to define a pair of radially deflectable wall portions 39 and 40 which have beveled surfaces 41 and 42 at the terminal ends thereof.

The wall portions 39 and 40 are moved and held in pressure engagement with the end portion 38 of the cable center conductor 14 by means of a clamping member 44 of dielectric material, preferably polyphenylene oxide, which has a central opening defining a generally cylindrical inner surface portion 45 which, in the assembly of the connector, engages the surfaces 41 and 42 of the wall portions 39 and 40 to cam the same inwardly. Movement of the clamping member 44 in the connecting direction is limited by engagement of an end surface 46 thereof with an internal shoulder 47 of the body member 20.

To maintain the clamping member 44 in centered relation to the cap member 19 and the body member 20, it has a first cylindrical surface 49 in relatively closely spaced relation to an internal cylindrical surface 50 of the cap member 19 and has a second cylindrical surface 51 of reduced diameter which is fitted within an internal cylindrical surface 52 of the body member 20. Preferably, the end of the body member 20 projects beyond the terminal ends of the wall portions 39 and 40 to prevent damage when the connector has disassembled.

An important feature is that the clamping member 44 is carried within the cap member 19 and is positively withdrawn when the cap member 19 is moved in a disconnecting direction. In accordance with this feature, the cap member 19 is formed with a radially inwardly projecting annular shoulder 54 which is engageable with a shoulder 55 of the clamping member 44, formed between the cylindrical surface 49 and the reduced diameter cylindrical surface 51. With this feature, it is not necessary to provide spring or other means for moving the clamping member in a disconnecting direction and with the positive actuation obtained upon movement of the cap member 19 in a disconnecting direction, release of the cable center conductor is insured.

Another important feature relates to the provision of ferrule member generally designated by reference numeral 57 which comprises a plurality of resilient finger portions 58 arranged to engage angularly spaced outer surface portions of the cable 11. Preferably, as shown in the enlarged end view of FIG. 5, six of such resilient finger portions 58 are provided. Preferably, the finger portions 58 have in-turned terminal end portions 58a for biting engagement with the cable. A pair of out-turned tabs 59 extend between member 44 and a ring 60 disposed in an internal groove of the cap member 19.

To actuate the finger portions 58, an annular cam member 61 is provided having an internal frusto-conical surface 61a engageable with the finger portions 58 to move the same inwardly in assembly of the connector. The cam member 61 is preferably provided with an annular shoulder engageable by an internal annular shoulder 62 of the cap member 19 and an annular seal member 63 is provided which is compressed between an end surface 64 of the cam member 61 and an internal shoulder 65 of the cap member 19, the seal member 63 being compressed into pressure engagement with the outer surface of a cable 11.

In the construction as illustrated in FIG. 2, the in-turned ends 58a of the finger portions 58 engage only the outer sheath 17 of the cable 11 and it is thus not necessary to strip the outer sheath from the cable. To provide a ground connection to the outer conductor 16 of the cable 11, the ferrule 57 is formed with an inner generally cylindrical wall 67 which is tightly fitted within the terminal end portion of the outer coaxial line conductor 17. The wall 67 is integrally connected through a radial wall 68 to the outer wall of the ferrule from which the finger portions 58 are formed by slotting. In the assembly of the connector, the radial wall 68 engages the clamping member 44. Preferably, the clamping member 44 is so formed as to provide a socket for receiving the end of the ferrule member 57, the socket including an internal generally frusto-conical surface 69 which facilitates centering of the ferrule 57.

To facilitate assembly and centering of the center conductor 14, the central opening of the clamping member 44 is formed with an internal generally frusto-conical surface 70, the smaller diameter end thereof being only slightly greater than the diameter of the conductor 14.

FIG. 3 is a cross-sectional view of the cap member 19 and associated parts before assembly. In assembly, after stripping a portion of the cable to expose a certain length of the center conductor, a tool may be used to enlarge the terminal end of the outer conductor 16. The cable is then inserted within the cap member, the end portion 38 of the center conductor 14 being passed through the central opening of the clamping member 44 after which the outer conductor 14 engages the inner wall 67 of the ferrule 57. The cap member 19 is then screwed onto the body member 20 and the in-turned end portions 58a of the fingers 58 are cammed into engagement with the cable sheath 17, the cable being moved axially with further movement of the cap member 19 in the connecting direction. During such movement, and through engagement of the beveled surface 41 and 42 of the finger portions 39 and 40 with the inner surface 45 of the clamping member 44, the fingers 39 and 40 are gradually forced into tight engagement with the end portion 38 of the center conductor 14. Movement of the cap member 19 in the connecting direction is limited by engagement of an end surface thereof with a shoulder 72 of the body member 20. An O-ring seal member 73 is preferably provided between the shoulder 72 and the threads and is compressed to a predetermined extent so as to provide an effective seal. A plug 74 may be removed to allow a pressurizing air or a suitable gas line to be attached.

Claims

1. In a connector for use with a cable having inner and outer conductors, a hollow cap member arranged to be disposed on said cable, a hollow body member, said members having end portions arranged to telescope one within the other when said cap member is moved in a connecting direction toward said body member, a ferrule disposed within said cap member and having inner and outer walls, contact means on said outer wall for engaging the outside of the cable, the outside diameter of said inner wall being greater than the normal inside diameter of the cable outer conductor, said inner wall and the cable outer conductor being stressed to obtain a tight frictional engagement therebetween, said contact means comprising a plurality of resilient finger portions, and camming means defining cam surfaces on said cap member for urging said fingers radially inwardly into tight engagement with said cable when said cap member is moved in said

2. In a connector as defined in claim 1, wherein the cable has a sheath portion around said outer conductor intermediate said outer conductor and

3. In a conductor as defined in claim 1, said ferrule including a generally cylindrical wall formed with axially extending angularly spaced slots to

4. In a connector as defined in claim 1, each of said fingers having an

5. In a connector as defined in claim 1, further including interengageable

6. In a connector as defined in claim 5, said camming means comprising an annular cam member within said cap member having a generally frusto-conical inner surface cammingly engageable with said fingers, said annular cam member and cap member having mating bearing surfaces permitting rotation of said cap member relative to said annular cam ring

7. In a connector as defined in claim 1, said cap and body members having interengageable stop surface portions to limit movement of said cap member relative to said body member in said connecting direction and a resilient seal ring on the outer surface portion of the inner one of said end portions, said cap and body members having surface portions engageable with said seal ring and operable to compress said seal ring to a

8. In a connector as defined in claim 1, a central conductor supported within said hollow body member for electrical connection to the cable inner conductor with there being an open space within said body member around said central conductor, first seal means operative between said cap member and the outside of said cable, second seal means operative between said cap and body members, and means for allowing introduction of a pressurized gaseous medium through the wall of said body member and into

9. In a connector for use with a cable having inner and outer conductors, a hollow cap member arranged to be disposed on said cable, a hollow body member, said members having end portions arranged to telescope one within the other when said cap member is moved in a connecting direction toward said body member, a ferrule disposed within said cap member and having inner and outer walls and means on said outer wall for engaging the outside of the cable, the outside diameter of said inner wall being greater than the normal inside diameter of the cable outer conductor, said inner wall and the cable outer conductor being stressed to obtain a tight frictional engagement therebetween, means for establishing an electrical connection between said ferrule and said hollow body member, a central conductor supported within said body member and having radially deflectable wall means defining an opening for receiving the cable inner conductor, and clamping means carried by and within said cap member and being arranged to cam said wall means radially inwardly into tight engagement with said end portion of the cable inner conductor when said cap member is moved in said connecting direction, said clamping member being withdrawn by said cap member when said cap member is moved in a

10. In a connector as defined in claim 9, said clamping member and said body member having surface portions interengageable to limit movement of

11. In a connector as defined in claim 9, the support of said central conductor being such as to provide an open space within said body member and around said central conductor, first seal means operative between said cap member and the outside of said cable, second seal means operative between said cap and body members, and means for allowing introduction of a pressurized gaseous medium through the wall of said body member and into

12. In a connector for use with a cable including a center conductor having an end portion projecting from one end of said cable, a hollow cap member arranged to be disposed on said cable, a hollow body member, said members having end portions arranged to telescope one within the other when said cap member is moved in a connecting direction toward said body member, a central conductor supported within said body member and having radially deflectable wall means defining an opening for receiving said cable center conductor, and a clamping member carried by and within said cap member and arranged to cam said wall means radially inwardly into tight engagement with said end portion of said center conductor when said cap member is moved in said connecting direction, said clamping means being withdrawn by said cap member when said cap member is moved in a disconnecting direction away from said body member, said clamping member having a central opening receiving said wall means and defining an inwardly facing surface for camming engagement with said wall means, said clamping member being separate from said cap member and being moveable axially relative thereto, said body member and said clamping member having generally cylindrical surface portions in facing relation when said clamping member is engaged with said wall means, the spacing and length of said generally cylindrical surface portions being such as to prevent canting of said clamping member until after said clamping means is disengaged from said wall means when said cap member is moved in said disconnecting direction.