US3406373A - Coaxial connector assembly - Google Patents

Description

Oct. 15, 1968 E. w. FORNEY, JR 3,406,373

COAXIAL CONNECTOR ASSEMBLY Filed July 26, 1966 2 Sheets-Sheet l Oct. 15, 1968 w, FORNEY, JR 3,406,373

COAXIAL CONNECTOR ASSEMBLY Filed July 26, 1966 2 Sheets-Sheet 2 United States Patent 3,406,373 COAXIAL CONNECTOR ASSEMBLY Edgar Wilmot Forney, Jr., Harrisburg, Pa., assignor to AMP Incorporated, Harrisburg, Pa. Filed July 26, 1966, Ser. No. 568,013 Claims. (Cl. 339-97) ABSTRACT OF THE DISCLOSURE A connector assembly for coaxial cable having a thin sheet outer conductor is taught which features a threaded connector body having a crimpable ferrule permanently attached thereto in which is positioned a separate backup sleeve inserted beneath the outer connector of a cable. The back-up sleeve includes a plurality of arms folded back to extend thereover. These arms include projections which are forced into the cable outer conductor when the ferrule attached to the body of the connector is c'rimped inwardly. The connector body includes an inner bore to receive the cable dielectric sheath inserted therethrough. The body of the connector includes two parts which are threadably intermated and the two parts include interior recesses housing a disk of sealing material which is deformed radially when the two parts are threaded together and caused to fiow inwardly against the dielectric sheath of the cable and outwardly against the surfaces of the body parts to provide a sealed connection.

Background of the invention In an attempt to answer the expanding needs of the communications industry a variety of new coaxial cables has been developed. As an example, there has been developed a cable which has a relatively fragile outer conductor made of thin copper sheet material. This outer conductor has a continuous seam extending along its length and is covered over by another thin sheet of conductive material such as aluminum also having a seam. The aluminum material seam is disposed opposite to the seam of the inner copper sheet so as to provide a complete shielding of the center conductor of the cable and further to provide a continuity of conductive material for confining and channeling the energy carried by the cable. The aluminum material is coated with an insulating material such as Mylar. This relatively fragile outer conductor is placed over a solid but deformable dielectric material which has a solid or stranded conductor coaxially disposed therein. The assembly of center conductor, dielectric material and outer conductor of sheet materials is then covered over with a relatively thick and tough insulating jacket. Many of the prior art devices which are adapted for use with coaxial cable were designed for use with outer conductors formed of either stranded braiding or metallic tubing of sufiicient strength to withstand substantial crimping forces or the heat of soldering when used with a coaxial connector. The new types of cable have made these older designs obsolete for such use and have caused considerable problems in termination. The tendency of efforts to terminate the new cable has been one leading away from the relative simplicity of some of the prior art devices, both in terms of structure and steps of application. As a related problem with certain of the newer types of cable having an outer conductor formed of thin conductive sheath material a difficulty in 3,406,373 Patented Oct. 15, 1968 providing a sealing has been experienced. One approach has been to utilize special adhesive materials hand applied to the connector during assembly. This approach to a large extent makes the quality of termination dependent upon the skill of the person utilizing the device, a result which experience has shown to be undesirable.

Summary of the invention This invention relates to a crimp-type coaxial connector assembly and particularly to an assembly adapted for use with a specialized coaxial cable having a relatively thin outer conductor which may be coated with insulating material.

Accordingly, it is an object of the invention to provide a connector for specialized coaxial cable of a type having a relatively thin outer conductor of sheath material coated with insulating material.

It is a further object of the invention to provide a crimp type coaxial connector assembly for thin conductor coaxial cable which has fewer parts and requires fewer steps in installation to cable than heretofore available.

It is another object of the invention to provide a coaxial connector assembly having improved characteristics with respect to the electrical interface obtainable with thin conductive material and with respect to sealing of coaxial cable.

It is still another object to provide an assembly for crimp type coaxial connectors which utilize a new concept of carrying and positioning the crimping ferrule of a the unit.

The foregoing objectives are attained through an assembly which includes a separate back up sleeve having a tubular portion insertable beneath the outer conductor of coaxial cable and a crimp ferrule united with the connector body and adapted to extend over the separate sleeve and outer conductor. In one embodiment the sleeve includes fingers which extend back over the outside of the outer conductor of the cable beneath the ferrule which is crimped inwardly to terminate the fingers and the outer conductor to the sleeve and. to the ferrule which is in turn integrally joined to the conductive material of the connector body. The cable is extended through the connector body which is made to contain a disk comprised of a sealing material which is deformed radially upon insertion of the connector into a matching receptacle to seal the assembly. As an important and novel feature of the invention the outer crimping ferrule is mechanically and electrically joined to the connector body and is carried thereby rather than as a loose piece in the prior art. This aspect although discovered relative to work with specialized cable is contemplated as being useful with standard cable constructions.

In the drawings:

FIGURE 1 is an exploded perspective view showing a segment of coaxial cable stripped for use with the connector assembly of the invention and showing further the various elements forming such assembly;

FIGURE 2 is a longitudinal view in partial section of the body portion of the receptacle part of the connector assembly of the invention;

FIGURE 3 is a longitudinal view in partial section of the body portion of the assembly carrying the outer crimping ferrule;

FIGURE 4 is an elevation of the sealing washer utilized with the assembly of the invention;

FIGURE is a longitudinal view in partial section showing the details of the inner sleeve member; and

FIGURES 6 and 7 are longitudinal sections showing respectively the full assembly of the invention in assembled relationship prior to and after the application of crimps to the outer ferrule to terminate the cable to the connector.

Description of preferred embodiment In FIGURE 1 the coaxial cable 10 is shown to include an outer jacket of 12 comprised of a resilient but tough insulating material such as polypropylene surrounding a cable outer conduct-or comprised of 14 and 16, a dielectric sheath 18 and a center conductor 20. The outer conductor of the cable 10 includes 'a first sheath of corrugated copper shielding which is relatively thin over which is wrapped a thin sheet of aluminum material which is typically coated with an insulation coating such as Mylar. The sheets of material of conductors 14 and 16 are oriented such that the seams thereof do not coincide whereby to provide a continuous conductive tube surrounding the cable dielectric and center conductor. The dielectric sheath 18 is typically formed of polyethylene and the center conductor is typically a solid copper rod.

The particular cable shown is known as a 75 ohm cable used for television signal transmission in CATV and related applications. It is to be understood that numerous other similar cable constructions may be served by the invention assembly to be hereinafter described. As one example, there is a cable made up like that shown in FIGURE 1 but having a dielectric sheath with an outer surface having the general appearance of a screw thread or corrugations and having an outer conductor comprised of a copper material plated thereon which although heavy for plating is still relatively thin as compared with the metallic tubing utilized in other coaxial cable.

In accordance with the-specific embodiments of the connector the cable is prepared as shown with the length between the end of 12 and the end of 20 being about 3% inches and the exposed length of the conductors 14 and 16 being about /8 inch. The outer aluminum material 16 is slit preferably in two places 180 apart for the purpose of permitting insertion of the inner sleeve. The sheath 18 is not dressed as shown in FIGURE 1 until after full assembly of the device which device serves in a sense as a jig or guide to facilitate the last stripping procedure which calls for removal of a portion of the sheath to expose the center conductor.

The connector assembly includes connector halves 24 and 44, a sleeve-70, and a seal 58. These are the only elements necessary to provide termination of the cable, at least in one standard type of termination. The half 24 represents a box fitting but could of course include portions similar to the half 44 for providing a disconnect termination of two cable halves. Alternatively two halves like 44 might be readily formed in a manner to provide a splice device.

FIGURE 2 shows the half 24 in greater detail to include a body 26 which is comprised of conductive metallic material machined to the configuration shown to include on the left enda threaded portion 28 relieved to accom modate an O-ring seal 30. The half 24 may be threaded into a threaded receptacle of the chassis of equipment served by the connector assembly. There is a bore 40 whichextends through 26 to accommodate the center conductor and dielectric portion of the cable made to extend through half 24 and into the box or chassis served thereby. On the opposite side of body 28 is a portion 32 having a recess in its outer surface to accommodate a nut 36 internally threaded as at 38. The face of 32 includes a relief as at 42 adapted to accommodate the seal The half 44 includes a body 46 of metallic material machined to the configuration shown. The body 46 is externally threaded as at 48 to mate with the threading of 38 of half 24. A bore 50 is provided through 46 to accommodate the dielectric, sheath and center conductor of the cable which is made to extend therethrough. The right handed end of a bore 50* is flared as at 52 to help feed the cable dielectric through the device. The enlarged diameter adjacent 52 is made to accommodate a tubular sleeve 54 which is in fact the outer crimping ferrule for the half 44. This ferrule is made of a malleable material such as soft copper and is firmly seated within 46 and may be soldered or brazed thereto as by the beading shown as 55. The forward face of 46 is relieved as at 56 to accommodate the seal 58. As can be discerned 54 is mechanically and electrically connected to 46; to the several advantages of reducing the number of loose pieces which must be handled during installation of the device; accurately and positively positioning the ferrule relative to the body; and providing conductivity from the outer crimping ferrule which is of substantially large area to the forward portion and body of the connector half.

In FIGURE 4 there is shown the seal 58 used with the connector assembly. The seal is comprised of a disk of relatively soft sealing material having a bore 66 therethrough which is just slightly larger than the outside diameter of the dielectric sheath 18 of the cable. The outer diameter is approximately equal to the diameter of the relieved portions 42 and 56. On each side of the sealing material may be provided washers 62 and 64 as shown which are made of paper or some other material to facilitate handling of the seal. In the particular embodiment shown the seal employed was un-vulcanized butyl rubber compound. This material has characteristics such that when compressed by assembly of the two halves 24 and 44 the seal is caused to flow into engagement with the dielectric sheath material on the inside thereof and with the surfaces of 42 and 56.'The sealing material then adheres and bonds to these surfaces to provide a gas proof seal protecting against leakage or flow of gas in either direction past the joint of location of the seal.

FIGURE 5 shows the sleeve member 70' which includes a central tubular body 72 which is preferably seamless and of a thickness to withstand the crimping forces applied thereto. The leading edge of 72 is beveled as shown at 73 to facilitate insertion beneath the outer conductors 14 and 16 of the cable. At the other end of 72 are integral extensions shown as 74 each carrying at the end thereof a plurality of foil penetrating barbs 76 formed by piercing the sheet material of 74 inwardly to provide sharp edges in the configuration shown in FIGURE 5. The embodiment of FIGURE 5 as indicated includes four members 74 but it is contemplated that depending upon the application fewer or greater than four could be employed. The members 74 prior to use are disposed as shown to permit the ferrule to be inserted beneath 14 with the members 74 positioned over 16.

During assembly the cable is prepared as is indicated in FIGURE 1. The inner sleeve 70 is then fitted on the cable and pushed axially therealong until the tubular portion 72 is completely beneath 14 with the members 74 extending back over 16. The half 44 is then axially placed on the cable and forced back until the end thereof overlies the jacket 12 of the cable and the dielectric material extends therethroug'h. During this assembly the forward part of 70 is stopped at the flared portion 52 is exactly and accurately position the half 44' on the cable. This is shown in FIGURE 6. As can be seenthis assembly procedure serves to force the member 74 in against 16 such that the parts of 76 penetrate and contact the'thin Mylar coating on16.

After the insertion of half of 44 to the position shown.

in FIGURE '6 the outer ferrule 54- may be crimped as shown in FIGURE7. The crimps shown as C1 and C2 are each comprised of two crimp segments which deform the material of the ferrule inwardly about the periphery of the cable to drive the outer conductor of the cable in against the outer surface of 72 and to tightly hold the assembly together. This same crimp deforms the members of 74 inwardly as indicated in FIGURE 7 to provide a mechanical connection of the connector assembly to the cable and to provide an electrical connection which extends continuity outwardly from the material of 70 to the material of 54 which is electrically joined with the body 46. The crimp C2 is made to compress the material 54 around in gripping relation to the jacket 12. Care should be taken with respect to crimp C2 so as not to overly deform the outer conductors 14 and 16 and cause a discontinuity in the cable. The axial length of 54 and the spacing between the crimps C1 and C2 serves to provide a mechanical connection of cable to connector assembly which better distributes loads applied from the cable to the assembly and which guards against working of the cable which could destroy the interface between the conductors of the cable and the conductive portions of the connector half.

Thereafter, the half 44 as attached to the cable may be threaded into the half 24 and drawn up tightly to flow the seal 58 to the configuration shown in FIGURES 6 or 7 and provide the sealing action heretofore described. The dielectric material which is shown to extend straight through the assembly may, of necessity, have to be trimmed off before this procedure in certain applications as for example, wherein the center conductor is not accessible and is poked into some kind of basket receptacle within the chassis or within another connector half. In many cases the center conductor is accessible and removal of the dielectric sheath may take place after the assembly evidenced in FIGURE 7 with the center conductor then being attached to a screw fitting within the chassis.

It is preferred that an O-type crimp as taught in Reissue Patent No. 25,847 granted Aug. 31, 1965, to E. W. Forney, Jr., be employed for the crimps C1 and C2.

Having now disclosed and described the invention in terms intended to enable its preferred practice it is defined by the appended claims to follow.

What is claimed is:

1. In a connector for coaxial cable of the type having an inner conductor surrounded by a dielectric sheath and an outer conductor, a connector body having a central bore therein of a diameter to receive the cable center conductor and dielectric sheath extended therethrough, a rear portion including a tubular extension mechanically and electrically joined to said body, said portion having an inner diameter to be fitted over the said cable and having a wall thickness and material characteristics to permit an inelastic deformation thereof inwardly to mechanically and electrically join said portion and thereby said body to the said cable, a separate sleeve member of conductive material having an outer diameter to be positioned within the outer conductor of said cable and an inner diameter to receive and support the dielectric sheath of said cable fitted therewithin, said sleeve member having a wall thickness and material characteristics to maintain its structural integrity during and after crimping forces applied to the said rear portion to crimp the outer conductor in against said sleeve member.

2. The connector of claim 1 wherein said sleeve member includes at its forward end at least one arm extending back over the outside of said member and adapted to be positioned over the outside of the outer conductor of said cable and within the said rear portion whereby upon application of said crimping forces to said rear portion said arm is driven inwardly and in contacting engagement with the outside of said cable outer conductor against the outer surface of said sleeve member.

3. The connector of claim 2 wherein said arm includes a series of inwardly directed projecting portions adapted to penetrate at least in part the outer conductor to assure an electrical connection therewith.

4. The connector of claim 3 wherein the cable outer conductor includes an insulating material disposed on the outer surface thereof and said projecting portions have a length to penetrate said insulating material.

5. A connector assembly for use with coaxial cable of the type having a center conductor surrounded by a dielectric sheath and an outer conductor including a connector body of conductive material having a bore there in adapted to receive and support the dielectric sheath carrying the center conductor through said body, an internal step portion adjacent said bore within said body and of a larger diameter than said bore, a metallic ferrule mechanically and electrically attached to said body and fitted within the larger part of said step portion to extend back from said body, said ferrule having a relatively thin wall construction and being comprised of material characteristics to permit deformation as by crimping, a sleeve member of relatively thin wall construction adapted to be fitted within said ferrule and beneath the outer conductor of said cable to receive and maintain during the life of said assembly, forces developed by an inward deformation of said ferrule against the outer conductor of said cable and said sleeve member, the said sleeve member having a diameter to engage said step portion whereby to limit the axial displacement of said member relative to said body and to fix the position of said cable relative to said body with the end of said outer conductor of said cable within said sleeve and proximate to the end of said body.

6. The assembly of claim 5 wherein said sleeve member includes one or more arms of conductive material attached to the forward end thereof and projecting back over the outside of said member to engage the outside surface of the outer conductor of said cable and to be driven inwardly thereagainst by a crimp applied to said ferrule.

7. The assembly of claim 6 wherein said arms include a series of inwardly directed projections adapted to penetrate at least in part the outer conductor of said cable to mechanically and electrically hold said cable within said assembly.

8. In an assembly adapted for use with a coaxial cable having an inner conductor, a dielectric sheath and an outer conductor stripped to expose axial segments of at least said dielectric sheath and said outer conductor, a first body member including a bore to receive the dielectric sheath inserted there through, said body including a rearwardly disposed recess of a diameter greater than the dielectric sheath, a ferrule fitted within the said recess having an inner diameter slightly greater than the outer diameter of the cable outer conductor, a loose piece sleeve member of an inner diameter approximating that of the dielectric sheath and of a wall thickness adapted to permit insertion of said member beneath the outer conductor of said cable whereby said member as positioned beneath said outer conductor may be inserted within said ferrule with the dielectric sheath extending through said body, the said outer ferrule having material characteristics to permit the inward deformation thereof as by crimping and the sleeve member having material characteristics to resist such inward deformation whereb to mechanically and electrically join said ferrule to said outer conductor, the said ferrule being electrically and mechanically connected to said first body member, a second body member adapted to receive said first body member and be mechanically and electrically connected thereto, each of the said body members including an inner recess defining a volume surrounding the dielectric sheath of said cable wherein said body members are assembled together, a seal comprised of a soft insulating material positioned in said volume and of a size to be compressed upon axial movement of said body members together to flow into an engagement with the surface of said dielectric sheath and the surfaces of said recess whereby to seal said assembly.

9. The assembly of claim 8 wherein said seal is comprised of un-vulcanized butyl rubber compound material.

10. The assembly of claim 9 wherein said seal includes 0n the forward and rearward faces thereof sheet material adapted to facilitate handling of said seal during the installation of said assembly on said cable.

References Cited UNITED STATES PATENTS Collier 1747 5.2 Bentley 174-89 Armstrong 33994 Caller 339l77 Gourley et a1 33994 FOREIGN PATENTS Great Britain.

MARVIN A. CHAMPION, Primary Examinen J. H. MCGLYNN, Assistant Examiner. l V

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