US3331917A

US3331917A - Coaxial and shielded in-line termination

Info

Publication number: US3331917A
Application number: US438493A
Authority: US
Inventors: Michael F O'keefe; Armand S Apa
Original assignee: AMP Inc
Current assignee: TE Connectivity Corp
Priority date: 1965-03-10
Filing date: 1965-03-10
Publication date: 1967-07-18
Anticipated expiration: 1984-07-18
Also published as: DE1565967A1; ES323996A1; NL6602826A; GB1066560A

Description

July 18, 1967 M. F. OKEEFE ETAL 3,331,917

COAXIAL AND SHIELDED IN-LINE TERMINATION Filed March 10, 1965 2 Sheets-$heet 1 2 INVENTOR.

All AND SAMUEL APA Jul 18,1967 O'KEEFE ETAL 3,331,917

COAXIAL AND SHIELDED IN-LINE TERMINATION Filed March 10, 1965 2 Sheets-Sheet 2 INVENTOR. ARMMuv SAMUEL APA MICHAEL Frumus O'KeEFe BY M hum S fib-uL United States Patent Filed Mar. 10, 1965, Ser. No. 438,493 Claims. (Cl. 174-75) ABSTRACT OF THE DISCLOSURE A coaxial or shielded cable terminal is disclosed which includes an in-line termination of inner and outer cable conductors through a structure including an inner body of insulating material containing a spring contact member for cable inner conductors and having positioned outwardly on the ends thereof rigid deformation resilient rings against which the cable outer conductor is forced by a thin malleable outer ferrule which extends along the length of the body. The inner contact insulating body and deformation resistant rings are covered over by a sleeve of insulating material made to extend out over the cable and an outer protective sheath thereof and ferrules are provided on each end of theouter sleeve to be crimped inwardly to seal all of the conductive metallic parts against the environment of use.

Background of the invention In-line terminals and splices are well-known and a wide variety of constructions are available. Most existing units however, either provide no sealing or include a relatively large number of loose pieces requiring a relatively time consuming assembly procedure and requiring a series of separately applied crimps of different geometries applied by different tools or by differently shaped dies in the same tool.

Summary of the invention This invention relates to an assembly of conductive and insulating elements adapted to be crimped or otherwise deformed to provide a sealed splice or termination of coaxial and shielded cable.

It is one object of the invention to provide a sealed terminal for coaxial or shielded cable which is of a unitary construction so arranged as to permit crimping in one stroke. A further object is to provide an in-line termination of coaxial and shielded cable which effectively seals the conductors terminated against the environment of use, particularly moisture. It is still another object to provide an in-line splice for mechanically and electrically joining the ends of coaxial or shielded cable in a manner to provide superior electrical characteristics and strength. It is a further object to provide a splice for mechanically and electrically joining the ends of coaxial or braided cable wherein only the outer conductor or braid of the cable need be terminated by deforming a ferrule thereover, the center conductors being accommodated by axial insertion into a resilient receptacle.

The foregoing objects are obtained through the invention in its application as a termination through the use of first and second ferrule members disposed respectively adjacent to the braid or cable outer conductor beneath and outside of an insulating sleeve which fits over the cable outer protective sheath. The ferrule members are axially spaced apart and are of diameters differing by the insulating sleeve thickness. The invention in its aspect as a splice includes the termination feature just described at either end of a continuous structure having a center dielectric insert carrying a double-ended Spring receptacle into which the cable center conductors are forced for the purposes of effecting an electrical union therebetween. In the splice embodiment the ferrule members adapted to terminate the braid are common and in all embodiments the ferrule members are of relatively thin metallic material so as to be readily deformable.

In the drawings:

FIGURE 1 is a perspective of the invention unit in the form of an in-line splice prior to insertion of cables therein and deformation;

FIGURE 2 is a longitudinal section of an in-line splice embodiment of the invention having one end terminated to coaxial cable and the other end undeformed with the cable prepared and in position for insertion therein; and

FIGURE 3 is an exploded View of the in-line splice embodiment of the invention showing separately the various parts thereof prior to assembly staking or final deformation.

The drawing figures are enlarged about four times from the actual size of an in-llne splice adapted for use with type RG-59/U shielded cable. The cable shown in FIGURE 2 includes a center conductor 2, a dielectric sheath 4, braid 6 and an outer protective sheath 8. The in-line splice depicted as unit 10 is comprised of a plurality of elements mechanically held together to form essentially one-piece which may be sold, shipped and handled as such without requiring assembly of a number of loose pieces. To utilize the unit 10, one need only prepare the coaxial or shielded cable in a manner indicated to the left of FIGURE 2 and insert the prepared end of the cable within the assembly. Thereafter, for reasons hereinafter to be given, the cable will be frictionally held within the splice so that controlled deformation of the ferrule members may be accomplished to perfect termination of the cable. The unit shown relates to a specific embodiment of the invention in the form of an in-line splice, but it is contemplated that as a part of the invention the termination performed on the outer end may be employed with a wide variety of constructions such as connectors, junctions and the like wherein the inner end would be replaced with a structure having threaded or bayonet-type fittings or a mounting flange. The invention as contemplated then relates to both a terminal and a splice.

Description of a preferred embodiment of the invention Looking now at the various elements of unit 10, the characteristics and structural relation thereof, reference is made to FIGURES l and 3 showing respectively, the assembly of the various elements and the elements prior to assembly. Beginning at the bottom of FIGURE 3 there is included as an integral structure, an insulating and protecting sleeve 12 which in an actual unit was made of polyvinyl chloride tubing sufficiently soft to permit the unique crimping operation to be hereinafter described. Prior to assembly of unit 10 the sleeve 12 is as shown in FIGURE 3, cylindrical along its length. After assembly the sleeve includes a pair of humps 12a axially spaced apart near but not at the ends of the sleeve. Fitted inside of 12 is a metallic sleeve 14 which is of a length to extend over a substantial portion of the length of 12. The sleeve 14 after insertion with 12 is deformed at each end to provide a turned portion 14a, forming a slight flange ex tending radially outwardly and a rounded and smooth entry extending inwardly. After insertion of the dielectric insert within sleeve 14, the sleeve is deformed circumferentially to form a ridge reducing the bore of 14 in the center thereof, indicated as 14b in FIGURE 2. In an actual embodiment the sleeve 14 was made ofthin tin-plated copper suitably softened by annealing to permit deformation at the ends thereof for crimping purposes. As will become apparent, sleeve 14 serves both as a ferrule and as a splice strengthening member. Sleeve 14 is positioned Within 12 in the manner indicated in FIGURE 1 and the end turned portions 1411 are dimensioned to deform the sleeve 14 outwardly to develop the humps 12a with the outward flange serving to lock the pieces together.

Fitted within sleeve 14 is aninsert 16 of dielectric material which has a center cylindrical portion 16a relieved as at 16b to cooperate with the indentation formed by 145 and lock the insert within 14. At each end of the cylindrical portion 16a is a further cylindrical portion 16c terminating in a flange portion 16d which is beveled on its outer surface and is perpendicular on its inner surface. Within 160 is a bore 16:: of a diameter approximately but slightly larger than the dielectric sheath of the cable to be terminated. At the inner end of bore 16c is a shoulder 16f sloped inwardly and relieved as at 16g to guide the cable center conductor within the splice as it is inserted. Extending fully through the insert between bores 16:: is a bore 16h adapted to receive a center contact member.

Over the outside of sleeve portions 16c are fitted sleeve members 18 which are axially forced thereon over the beveled outer surface of 16d. The sleeve members 18 are of a length to nest between the transition surface of the insert and the inner end of 160 and the inner vertical surface of portion 16d in the manner shown in FIGURE 2. The thickness and material characteristics of member 18 are such as resist deformation under crimping forces applied radially inwardly to the portions of 14 diposed over the sleeves 18. At the outer end of the sleeves there is a beveled portion 18a which mates with the beveled portion of 16d to provide a continuous surface engaged by the outer conductor or braid of the cable upon insertion. As shown in FIGURE 2 the cable braid is guided thereby outside and over the surface of the sleeve 18 and within 14, the flaring at 14a assisting. The serrations 18b extending around and over the outside of 18 are provided to contact the braid or outer conductor of the cable and operate during crimping to drive the braid material into the material of 12 to assure a good interface of clean metal in the Zone of termination.

Within insert 16 as shown in FIGURE 2 in position and in FIGURE 3 in perspective, as a one-piece contact member 20 which is sleeve-like in the center, with spring portions 20a formed at each end, around the center of 20- is a slight indentation 20b which operates to limit the insert of the cable center conductors. The outside diameter of 20 relative to the bore 16h, is such that the contact is wedge-fitted within the insert to resist axial displacement. Member 20 is made of conductive material having spring characteristics and the outer ends of the spring portion 20a are beveled as at 200 to facilitate entry of the cable center conductor.

To complete the unit 10, a pair of ferrules 22 are provided which are of malleable material and of a thickness to permit the deformation indicated in FIGURE 2 at the right-hand side thereof. The inner diameter of each is dimensioned to match the outer diameter of sleeve 12 in its relaxed state so that the ferrules 22 may be fitted thereover and positioned inwardly to a point of engagement with the humps 1211. Thereafter, the ferrules are locked on 12 by dimples 22a disposed at several points around the ferrule periphery which is just sufficient to hold the ferrules in place.

In use the cable is prepared as shown in FIGURE 2 and inserted within the end of assembly 10; the center conductor shown as 2 being positioned and forced within" the spring portions of the member 20, the dielectric shown as 4, fitting within the bore 16a of the insert and the braid or outer conductor 6 being guided out over 18 and under the outer portions of 14. The preparation of the cable is such as to leave the outer insulating and protective sheath 8 continuous for a length so that as the cable is inserted the sheath extends well within 12 and fully under 22.

With the cable so inserted the unit 10 is then deformed with one crimp being applied to 22 over 12 to drive such inwardly and another crimp being applied directly to 12 over 18 to deform portions of 14. It is generally preferred that circular crimps be applied in both instances. A description of one preferred type is given in US. Patent No. 3,010,184 to Edgar W. Forney, J r.

The spring of ferrule 22 relative to the entry of the cable and in conjunction with the sleeve 12, which is somewhat flexible, operate to permit bending loads on the cable without straining the contact interfaces within the unit. Additionally, sudden axial loads applied to the cable are accommodated by the resiliency of the sleeve 12 and the clamping thereof by 22 spaced outwardly of the connector of the cable outer conductor.

In applications wherein the termination and splice of the invention are utilized for higher frequency signals the insert with respect to dimension and dielectric constant may be based upon calculations to provide a substantially matched impedance along its length in the presence of conductive path diameter changes.

The foregoing description is intended to serve as a disclosure of a preferred mode of practicing the invention, which is now claimed.

What is claimed is:

1. In a terminal for coaxial or shielded cable of the type having an inner conductor surrounded by a dielectric sheath, an outer conductor and a protective sheath, the combination comprising a centrally disposed body of dielectric material having a bore adapted to accommodate the insertion of the cable dielectric sheath and inner conductor, a contact member secured in said bore adapted to receive the cable inner conductor, an end portion of said body having an outer diameter slightly larger than that of the diameter of the cable outer conductor and less than the outer diameter of the said body adjacent said end portion with the outer end of said end portion being beveled inwardly to guide said outer conductor thereover during installation, a hard deformation resistant ring fitted over said end portion and aflixed thereto, said ring having an axial length slightly less than that of said end portion and a maximum outer diameter approximately equal to that of the end of said end portion and a thin malleable conductive sleeve member extending over said body, said end portion and said ring, the sleeve member having an inner diameter sufficiently greater than said ring to accommodate the volume of said cable outer conductor when inserted therewithin over said ring and adapted to be deformed inwardly to drive said cable outer conductor inwardly against said ring to terminate said outer conductor to said sleeve member inner surface, the said sleeve member and ring having material characteristics relative to each other whereby deformation of said sleeve to terminate said cable outer conductor to said sleeve member may be achieved without changing the inner diameter of said ring.

2. The terminal of claim 1 wherein there is included an outer insulating sleeve surrounding said conductive sleeve member and extending therealong and outwardly over the end thereof, said insulating sleeve having an inner diameter along its length approximating the outer diameter of said conductive sleeve member, a thin malleable ferrule positioned on said outer insulating sleeve on the portion thereof extending beyond said conductive sleeve member, said insulating sleeve having a thickness and material characteristics to permit deformation of said conductive sleeve member through said insulating sleeve and to be deformed into a sealing engagement with the dielectric sheath of said cable upon deformation of said ferrule positionedthereon.

3. The terminal of claim 2 wherein said insulating sleeve extends axially outward of said conductive sleeve and has an inner diameter extending for a substantial length to accommodate the cable protective sheath and there is included a further sleeve positioned around said insulating sleeve at a position axially spaced from said conductive sleeve, said further sleeve being adapted to be deformed inwardly to drive said insulating sleeve into a tight gripping relationship with the cable insulating sheath.

4. In a terminal for coaxial or shielded cable of the type having a center conductor surrounded by a dielectric sheath, an outer conductor and an outer protective sheath, the combination comprising a body of dielectric and insulating material including a first central bore, a contact member disposed in said bore adapted to receive the cable center conductor, a second bore in said body axially aligned with said first bore and of a larger diameter to accommodate and support the dielectric sheath of said cable to 'be inserted therein, the body portion surrounding said second bore being of a reduced wall thickness, a first metallic sleeve of rigid deformation resistant material disposed around and extending along the portion of said body overlying said second bore, a second metallic sleeve of thin malleable material secured to said body and extending over said body and over said first metallic sleeve, the interior of said second sleeve being spaced from said first sleeve by an amount sufficient to accommodate the insertion of the cable outer conductor, an insulating sleeve surrounding said second sleeve and extending thereover axially outwardly of said first and second sleeves, a third metallic sleeve disposed over said insulating sleeve toward the outer end thereof and adapted to be deformed inwardly to hold the insulating sleeve material inwardly against the outer protective sheath of said cable whereby to seal the forward contact portion of said termination against contaminants and to provide a flexible support of said cable at a point axially spaced from the entry of the outer and inner conductors in the area of termination.

5. The terminal assembly of claim 4 wherein said first metallic sleeve is staked to said body against axial displacement relative thereto, said portion of said body of reduced wall thickness includes an outer flange engaging an end, surface of said second sleeve to hold such against axial displacement relative to said body and the said third ferrule is secured to said outer insulating sleeve against axial displacement.

6. The terminal of claim 4 wherein the outer diameter of said first sleeve is approximately equal to the inner diameter of the third sleeve plus twice the wall thickness of said insulating sleeve.

7. The terminal assembly of claim 4 wherein the outer end of the body portion of reduced wall thickness and the outer end of the second sleeve are shaped in a complementary angle and engaged to provide a substantially continuous bevel tending to guide the outer conductor of said cable outwardly and over said second sleeve.

8. The terminal assembly of claim 7 wherein the outer end of said first sleeve is spaced axially outwardly of the outer end of said second sleeve.

9. The terminal assembly of claim 8 wherein the outer end of said first sleeve is rounded in an outward sense to guide the ends of the cable outer conductor upon insertion inwardly to slide between said first sleeve and said second sleeve.

10. The terminal assembly of claim 9 wherein the outer end of said first sleeve includes an outwardly directed flange portion adapted to deform said insulating sleeve to develop an annular outward deformation limiting insertion of said third sleeve onto said insulating member.

References Cited UNITED STATES PATENTS 2,774,810 12/1956 Ritter 174-90 X 2,904,609 9/1959 Forney 17488 3,147,057 9/1964 Colussi 17488 X DARRELL L. CLAY, Primary Examiner.

Claims

1. IN A TERMINAL FOR COAXIAL OR SHIELDED CABLE OF THE TYPE HAVING AN INNER CONDUCTOR SURROUNDED BY A DIELECTRIC SHEATH, AN OUTER CONDUCTOR AND A PROTECTIVE SHEATH, THE COMBINATION COMPRISING A CENTRALLY DISPOSED BODY OF DIELECTRIC MATERIAL HAVING A BORE ADAPTED TO ACCOMMODATE THE INSERTION OF THE CABLE DIELECTRIC SHEATH AND INNER CONDUCTOR, A CONTACT MEMBER SECURED IN SAID BORE ADAPTED TO RECEIVE THE CABLE INNER CONDUCTOR, AN END PORTION OF SAID BODY HAVING AN OUTER DIAMETER SLIGHTLY LARGER THAN THAT OF THE DIAMETER OF THE CABLE OUTER CONDUCTOR AND LESS THAN THE OUTER DIAMETER OF SAID BODY ADJACENT SAID END PORTION WITH THE OUTER END OF SAID END PORTION BEING BEVELED INWARDLY TO GUIDE SAID OUTER CONDUCTOR THEREOVER DURING INSTALLATION, A HARD DEFORMATION RESISTANT RING FITTED OVER SAID END PORTION AND AFFIXED THERETO, SAID RING HAVING AN AXIAL LENGTH SLIGHTLY LESS THAN THAT OF SAID END PORTION AND A MAXIMUM OUTER DIAMETER APPROXIMATELY EQUAL TO THAT OF THE END OF SAID END PORTION AND A THIN MALLEABLE CONDUCTIVE SLEEVE MEMBER EXTENDING OVER SAID BODY, SAID END PORTION AND SAID RING, THE SLEEVE MEMBER HAVING AN INNER DIAMETER SUFFICIENTLY GREATER THAN SAID RING TO ACCOMMODATE THE VOLUME OF SAID CABLE OUTER CONDUCTOR WHEN INSERTED THEREWITHIN OVER SAID RING AND ADAPTED TO BE DEFORMED INWARDLY TO DRIVE SAID CABLE OUTER CONDUCTOR INWARDLY AGAINST SAID RING TO TERMINATE SAID OUTER CONDUCTOR TO SAID SLEEVE MEMBER INNER SURFACE, THE SAID SLEEVE MEMBER AND RING HAVING MATERIAL CHARACTERISTICS RELATIVE TO EACH OTHER WHEREBY DEFORMATION OF SAID SLEEVE TO TERMINATE SAID CABLE OUTER CONDUCTOR TO SAID SLEEVE MEMBER MAY BE ACHIEVED WITHOUT CHANGING THE INNER DIAMETER OF SAID RING.