US3915539A - Coaxial connectors - Google Patents

Abstract

In a coaxial connector, the outer shell and back nut are injection mouldings of synthetic, non-conductive material. A metal sleeve in the shell provides electrical continuity for the outer conductor. The end of the sleeve projects slightly to abut and make connection to the outer conductor of a second, mating connector. This end of the sleeve is sealed against moisture by a surrounding O-ring clamped between the two connectors.

Description

United States Patent Collins 5] Oct. 28, 1975 1 COAXIAL CONNECTORS 3,245,028 4/1966 Badger 339/48 3.363.221 1/1968 Stark 339/177 E [75] Inventorg C011, Rochester 3,428,739 2/1969 Jackson 339/177 R ng an [73] Assignee: C & S. Antennas Limited,

Rochester, England Primary Examzner-Roy Lake Assistant ExaminerMark S. Bicks 1 1 Flledi y 1974 Attorney, Agent, or FirrnWi1liam R. Woodward [21] Appl. No.: 474,982

Related U.S. Application Data [63] Continuation of Ser. No. 254,151, May 17, 1972, [57] ABSTRACT abandoned.

In a coaxial connector, the outer shell andback nut 30 Foreign Application Priority Data are je molulldings 9 sy fi qgt materia meta s eeve m t e s e provi es e ectrica May 1971 United Kmgdom 6106/7! continuity for the outer conductor. The end of the [52] U S Cl 339/94 0 339/177 E sleeve projects slightly to abut and make connection [51] hit Cl llllllllllllllllllllllll H01R 7/02 to the outer conductor of a second, mating connector. [58] Fie'ld 49 B 92 R This end of the sleeve is sealed against moisture by a 339/92 M C surrounding O-ring clamped between the two connectors.

[56] References Cited UNITED STATES PATENTS 3 Clams l D'awmg F'gure 2,955,148 10/1960 Graham 339/177 R U.S. Patent cm. 28, 1975 3,915,539

This is a continuation of application Ser. No. 254,151, filed May 17, 1972, and now abandoned.

This invention relates to coaxial connectors. Coaxial connectors are ever more frequently being employed in modern communications applications, and much effort has been directed to the production of reliable connec: tors at minimum cost. However, to provide for an electrical connection for the outer conductor, conventional connectors are largely fabricated from conductive metals such as aluminium or brass and are therefore inherently expensive, since these starting materials are expensive and their processing (for example by machine turning) is also expensive.

With the object of cheapening manufacture, coaxial connectors have already been proposed in which the main body is made from a synthetic plastics material and a conductive path for the outer conductor of the cable is provided by a metallized coating on the main body or by a thin metal liner.

A problem which is encountered with heavy duty connectors used in all different kinds of environments is that of metal corrosion, which is encouraged when dissimilar metals are in contact.

The object of this invention is to provide a connector which overcomes the problem of corrosion.

According to the present invention,there is provided a coaxial connector comprising an outer shell terminating in a flange for attaching the connector to another connector, a contact element for the inner conductor of a coaxial cable supported by a dielectric body within the outer shell, the outer shell being formed from a moulded synthetic, non-conductive material and lined by a metal sleeve forming a conductive path for the outer conductor of the cable, the sleeve projecting slightly with respect to the end surface of the shell at the flange end, and sealing means providing a watertight seal for the interior of the connector except in the vicinity of the flange.

In use, the connector is attached to another connector by means of a flange and a sealing ring is compressed between the flange and the other connector around the projecting end of the metal sleeve. This measure, in conjunction with the aforesaid sealing means, ensures that the conductive parts of the connector are completely sealed off inside the synthetic material and problems of corrosion are thereby avoided.

The invention will be described, by way of example, with reference to the sole FIGURE of the accompanying drawing, which is a cross-section of one connector and part of a second connector attached thereto.

The connector illustrated comprises atubular body shell 10 which carries at one end aflange 12 which is provided with threefixing holes 14. The flange is rotatably mounted on the body by means of asnap ring 16. The other end of theshell 10 is externally threaded at 11 to receive atubular back nut 18. The further end of theback nut 18 is directed inwards to form anabutment 20 which bears against athrust ring 22 which in turn presses against arubber sealing ring 24. Aninternal shoulder 19 of theback nut 18 bears on an internally threadedcollar 26 and thering 24 also bears on this collar. Rotation of theback nut 18 thus applies pressure to the internally threadedcollar 26. Thecollar 26 is chosen to suit the external conductor of the cable to which the connector member is connected, which in this case is assumed to have an Edison thread on its outer surface. Spanner flats (not shown) can be provided on the outside of the body shell to assist the relative rotation of back nut and shell.

A conductingmetal sleeve 30 is provided within theshell 10 and is flanged at the end nearer theback nut 18. Theflange 32 is clamped between thecollar 26 and I the end surface of theshell 10. A sealingring 28 is housed in a groove at the end. of theshell 10 between this shell and theflange 32. The other end 31 of the sleeve stands very slightly proud of the surface of theflange 14 to ensure a positive electrical connection at this point, by abutment with thecorresponding sleeve 30 of a second connector. Thesleeve 30 can be made by metal spinning or deep drawing.

In use the connector member is attached to a coaxial cable as follows. Theback nut 18 is placed over the end of the cable and suitable thrust and sealingrings 22 and 24 respectively are chosen with an internal diameter equal to the external diameter of the outer sheath of the cable, or of the bared outer conductor. The bared outer conductor of the cable is screwed into the threadedcollar 26 until it protrudes from the further side, and the protruding portion is then turned outwards to form a flange. The back nut assembly is screwed on to the body shell 111) with the flange formed by the outer conductor bearing against theflange 32 on thesleeve 30 to provide a positive electrical connection between the outer conductor of the cable and the sleeve.

The central conductor of the cable engages with aninner contact element 34 which is supported within thebody member 10 by adielectric disc 36. As shown the engagement is by means of a push fit, but it could alternatively be provided for, in a manner known per se, by a self-tapping thread on the left-hand portion of theelement 34, as seen in the FIGURE, there being a transverse bore through the right-hand portion of theelement 34 to receive a tommy bar for screwing the contact element into the central conductor of the cable.

Theshell 10 may have an aperture (not shown) in its wall by means of which dry gas. can be introduced into the connector. The gas then circulates around an annular channel formed in the inner surface of theshell 10 and passes through a hole in thesleeve 30. The provision of the annular channel avoids the necessity of aligning the holes in theshell 10 and thesleeve 30.

The largest components are theshell 10 and theback nut 18, and these are made of a synthetics plastics material, preferably glass-filled nyl-on. This has good ultraviolet resistance, especially if loaded by a suitable black pigment, good creep resistance and low waterabsorption characteristics, and theshell 10 andnut 18 can be formed by injection moulding. In the connector illustrated theflange 12 is formed of the same material, and thecollars 22 and 26 could be also. The use of plastics members for the major components means that the connector can be produced relatively cheaply.

The interior of the connector is completely sealed against the ingress of rnois ture. The cable entry is sealed by therubber ring 24 compressed about the cable sheath, or about the bared outer conductor as may be preferable when the external diameter of the outer sheath varies within wide tolerances. To improve the efficiency of this seal we have found it advantag'e'ous to taper the outside of thering 24, the narrower end being to the left in the drawing. The ring, in place on the cable, is then forced into the back nut after the manner of a rubber bung.

The joint between theshell 10 and theback nut 18 is sealed by thering 28. The only other place where moisture could reach the metal parts of the connector is at the projecting end 31 of thesleeve 30 at the leading end of the connector. To seal off this region, the leading end of theshell 10 has anannular groove 36 surrounding the sleeve end 31. This groove faces thecorresponding groove 36 in theshell 10 of the second connector and an O-ring 38 is housed between these grooves. When the flanges l2 and 12 are clamped up by bolts (not shown) through theholes 14 and 14, the sleeve ends 31 and 31' abut each other to provide electrical continuity through thesleeves 30 and 30' and the O-ring 38 is compressed between the shells l and to complete the sealing of the connectors.

Connection between thecontact element 34 and the corresponding element of the second connector is effected by ametal pin 40. I

The major components can be used with a variety of different cable types, thus enabling the advantages of mass production to be further realised. Therings 22 and 24 andcollar 26 can be replaced by any suitable fixing appropriate to the cable to be used with the connector. For example, a plain collar can be used as 0pposed to a threaded one, or two clamping members having opposed frusto-conical surfaces can be employed. In all cases axial thrust generated by tightening theback nut 18 serves to clamp the outer conductor and form the seal around the conductor itself or the sheath thereof.

O-ring seals have been used in the past between the flanges of connectors. Although these have prevented water getting inside the connector they have not served to seal all metal parts inside the connector; in fact the O-rings have been between metal flanges. The known seals have not therefore helped to prevent corrosion between dissimilar metal parts which are inevitably present because of the use of cables with conductors of copper or aluminium. In the past it has been necessary to employ special barrier paints to overcome the problem of corrosion. This is a troublesome and unreliable method of dealing with the problem.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A pair of coaxial cable connectors connected together, each comprising an outer shell terminating in a flange whereby the connector is attached to the other connector, a dielectric body within the outer shell, a contact element for the inner conductor of a coaxial cable supported by the dielectric body, the outer shell being formed from a moulded synthetic, nonconductive material, a metal sleeve lining the interior of the outer shell and forming a conductive path for the outer cable conductor, the sleeve projecting slightly with respect to the end surface of the shell at the flange end, the sleeve being itself unflanged at its projecting end, and sealing means at the end of the shell remote from the flange, said sealing means of the respective connectors together providing a watertight seal for the interior of the connector and preventing access of moisture to the metal sleeves except in the vicinity of the flange, said projecting ends of the two metal sleeves of the respective connectors abutting each other and providing electrical continuity through the sleeves, and a sealing ring clamped between the respective flanges of the two shells around the abutting ends of the sleeves to complete the watertight sealing of the connector and complete the prevention of the access of moisture to the metal sleeves.

2. A coaxial connector for a coaxial cable comprising an outer shell terminating in a flange for attaching the connector to another connector with interposition of a sealing ring, a dielectric body within the outer shell, a contact element for the inner conductor of a coaxial cable supported by the dielectric body, the outer shell being formed from a moulded synthetic, nonconductive material, a self-supporting metal sleeve of solid metal lining the interior of the outer shell and forming a conductive path for the outer conductor of the cable, the sleeve projecting axially slightly with respect to the end surface of the shell at the flange end for endwise abutment under pressure with the sleeve of a like connector, the projecting end of said sleeve being supported axially solely by said sleeve itself and being capable of withstanding a compressive load created by said endwise abutment under pressure, and sealing means at the end of the shell remote from the flange providing a watertight seal for the interior of the connector and preventing the access of moisture to the metal sleeve except in the vicinity of the flange, where a similar seal to complete the sealing of the connector is feasible upon attachment of the flange to another connector with interposition of a sealing ring.

3. A coaxial connector for a coaxial cable comprising an outer shell terminating in a flange for attaching the connector to another connector with interposition of a sealing ring, a dielectric body within the outer shell, a contact element for the inner conductor of a coaxial cable supported by the dielectric body, the outer shell being formed from a moulded synthetic, nonconductive material, a metal sleeve lining the interior of the outer shell and forming a conductive path for the outer conductor of the cable, the sleeve projecting slightly with respect to the end surface of the shell at the flange end for endwise abutment with the sleeve of a like connector, and sealing means providing a watertight seal for the interior of the connector and preventing the access of moisture to the metal sleeve, except in the vicinity of the flange, where a similar seal is feasible upon attachment of the flange to another connector,

said sealing means comprising a back nut threaded on the end of the shell remote from the flange, and sealing rings within the back nut, the back nut being adapted to compress the sealing rings around the cable, the end of the metal sleeve being flared out to overlay the end surface of the shell remote from the flange and a sealing ring being interposed between the flared out part of the sleeve and the shell.

Claims (3)

1. A pair of coaxial cable connectors connected together, each comprising an outer shell terminating in a flange whereby the connector is attached to the other connector, a dielectric body within the outer shell, a contact element for the inner conductor of a coaxial cable supported by the dielectric body, the outer shell being formed from a moulded synthetic, non-conductive material, a metal sleeve lining the interior of the outer shell and forming a conductive path for the outer cable conductor, the sleeve projecting slightly with respect to the end surface of the shell at the flange end, the sleeve being itself unflanged at its projecting end, and sealing means at the end of the shell remote from the flange, said sealing means of the respective connectors together providing a watertight seal for the interior of the connector and preventing access of moisture to the metal sleeves except in the vicinity of the flange, said projecting ends of the two metal sleeves of the respective connectors abutting each other and providing electrical continuity through the sleeves, and a sealing ring clamped between the respective flanges of the two shells around the abutting ends of the sleeves to complete the watertight sealing of the connector and complete the prevention of the access of moisture to the metal sleeves.

2. A coaxial connector for a coaxial cable comprising an outer shell terminating in a flange for attaching the connector to another connector with interposition of a sealing ring, a dielectric body within the outer shell, a contact element for the inner conductor of a coaxial cable supported by the dielectric body, the outer sheLl being formed from a moulded synthetic, non-conductive material, a self-supporting metal sleeve of solid metal lining the interior of the outer shell and forming a conductive path for the outer conductor of the cable, the sleeve projecting axially slightly with respect to the end surface of the shell at the flange end for endwise abutment under pressure with the sleeve of a like connector, the projecting end of said sleeve being supported axially solely by said sleeve itself and being capable of withstanding a compressive load created by said endwise abutment under pressure, and sealing means at the end of the shell remote from the flange providing a watertight seal for the interior of the connector and preventing the access of moisture to the metal sleeve except in the vicinity of the flange, where a similar seal to complete the sealing of the connector is feasible upon attachment of the flange to another connector with interposition of a sealing ring.

3. A coaxial connector for a coaxial cable comprising an outer shell terminating in a flange for attaching the connector to another connector with interposition of a sealing ring, a dielectric body within the outer shell, a contact element for the inner conductor of a coaxial cable supported by the dielectric body, the outer shell being formed from a moulded synthetic, non-conductive material, a metal sleeve lining the interior of the outer shell and forming a conductive path for the outer conductor of the cable, the sleeve projecting slightly with respect to the end surface of the shell at the flange end for endwise abutment with the sleeve of a like connector, and sealing means providing a watertight seal for the interior of the connector and preventing the access of moisture to the metal sleeve, except in the vicinity of the flange, where a similar seal is feasible upon attachment of the flange to another connector, said sealing means comprising a back nut threaded on the end of the shell remote from the flange, and sealing rings within the back nut, the back nut being adapted to compress the sealing rings around the cable, the end of the metal sleeve being flared out to overlay the end surface of the shell remote from the flange and a sealing ring being interposed between the flared out part of the sleeve and the shell.

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