US3349165A

US3349165A - Cable termination

Info

Publication number: US3349165A
Application number: US592920A
Authority: US
Inventors: Zimmerman Arie
Original assignee: Anaconda Wire and Cable Co
Current assignee: Ericsson Inc
Priority date: 1966-11-08
Filing date: 1966-11-08
Publication date: 1967-10-24
Anticipated expiration: 1984-10-24

Description

Oct. 24, 1967 A. ZIMMERMAN 3,349,165

CABLE TERMINATI ON I Filed Nov.' 8, 1966 INVENTOR.

A. ZlM/ME MAN BY /%/J m 4cm United States. Patent 3,349,165 CABLE TERMINATION Arie Zimmerman, Los Angeles, Calif. Anaconda Wire and Cable Co., 605 3rd Ave., New York, NY. 10016) Filed Nov. 8, 1966, Ser. No. 592,920 6 Claims. (Cl. 174-75) ABSTRACT OF THE DISCLOSURE In a cable termination, the combined outer conductor and jacket are pressed into a double-walled ferrule. The invention features a ferrule having its inner tubular wall longer than its outer wall.

My invention relates to a cable termination and particularly to a termination for a coaxial cable where the outer conductor and the jacket of the cable are firmly bonded together.

A type of electric cable has recently assumed commercial importance having the outer jacket bonded firmly to an underlying metal conductor or shielding which is most usually comprised of aluminum. Such a cable is exemplified by the coaxial cable described in application Serial Number 422,275 assigned to the assignees of the present invention.

It is difficult to terminate this cable by conventional means since the jacket cannot be removed from the conductor for the purpose of clamping or soldering on a connection. The problem is aggravated when the conductor is aluminum due to the well known fact that the oxide layer on the surface of aluminum offers an obstacle to making a sound electrical connection.

By my invention I propose to make a cable termination that is very easily applied by simple hand tools.

In the termination of my invention it is not necessary to separate the cable conductor or shielding from the jacket to which it is bonded.

I further propose in the termination of my invention to make a permanent, efficient electrical connection, even to aluminum.

And I further propose by my invention to make a termination that is particularly advantageous for use in multitaps.

I have invented a termination in a cable having a tubular conducting member, such for a preferred example as an aluminum member, and an insulating jacket surrounding this member and bonded to it. Such a cable will comprise a coaxial cable with an inner conductor and an annular wall of insulation between the inner conductor and the conducting member. My termination embodies a unitary conducting ferrule comprising inner and outer concentric tubes circumferentially joined at one end with the inner tube substantially longer than the outer tube. The inner tube is inserted directly under the conducting member and over the wall of insulation, and the outer tube is applied over the jacket. The outer tube is compressed, preferably in the shape of a regular polygon, thereby locking the ferrule onto the cable and grounding the conducting member.

A more thorough understanding of my invention may be gained from a study of the appending drawing.

In the drawing:

FIGURE 1 shows an exploded pictorial view of my termination prior to compressing the ferrule.

3,349,165 Patented Oct. 24, 1967 FIGURE 2 shows a pictorial view of the termination of my invention.

Referring to the drawings, a coaxial cable indicated generally by the numeral 10 is comprised of an inner conductor 11, and an annular wall of insulation 12 such, for example, as polyethylene or expanded polyethylene surrounding the conductor 11. An outer aluminum conductor 13, which is bonded to a plastic jacket 14, has been spread away .from the insulation 12 by means of a flaring tool. The jacket 14 is usually formed of polyethylene or polyvinylchloride. It will be understood that although my invention has special utility where the conductor 13 is aluminum it is useful also for other conducting material such as copper. A metal ferrule 16 is comprised of an outer tube 17 and an inner tube 18 joined together at one end 19 in a unitary structure, with the tube 18 being sufiiciently longer than the outer tube 17 to proect substantially beyond the outer tube. The diameter of the tube 18 is such as to provide a slide fit over the insulation 12, and the length of the flared portion of the conductor 13 is sufficient to insert the tube 18 and have a cut end 21 of the conductor-jacket combination project snugly against the end 19 of the ferrule 16 between the two

tubes

17 and 18. After the ferrule 16 is fitted in place on the cable 10 the tube 17 is compressed in a die which may conveniently be fitted within a hand tool of known type, to form the hexagonal shape shown in FIGURE 2. Because the tube 18 is longer than the tube 17, a shoulder 22 remains after the tube 17 has been compressed and this shoulder maintains a positive pressure between the tube 17 and the conductor 13 breaking through the oxide layer on the conductor and insuring against loss of conductivity in the connection. The extra length of the tube 18 also prevents the edge of this tube from cutting into the conductor 13 when the ferrule is compressed. In this regard it should be noted that in coaxial cables of the type for which my invention is particularly adapted, the conductor 13 may be very thin, of the order of 6 mils, and easily cut, with a resulting electrical discontinuity, if the edge of the inner tube were under the length being compressed.

When the termination of my invention is used to make an electrical connection the hexagonally shaped ferrule portion 16 is inserted under a grounding strap while the projecting conductor 11 is inserted into a terminal clamp. Because very little bulk has been added to the cable by my termination a plurality of my terminations may be connected to a multitap of modest dimensions.

I have a new and useful termination for which I desire an award of Letters Patent.

I claim:

1. A termination in a cable having a tubular conducting member and an insulating jacket surrounding said member and bonded thereto, comprising:

(A) a unitary conducting ferrule comprising inner and outer concentric tubes circumferentially joined at one end,

(a) the inner of said tubes being substantially longer than the outer of said tubes,

(b) said inner tube being inserted directly under said conducting member, and

(c) said outer tube being applied over said jacket,

(d) said outer tube being compressed thereby locking said ferrule onto said cable and grounding said conducting member.

2. The termination of claim 1 wherein said outer tube 6. The termination of claim 4 wherein said conducting is compressed in the shape of a regular polygon. member is aluminum.

3. The termination of claim 1 wherein said conducting V a member is aluminum. b1 References Cited 4. The termination of claim 1 wherein said ca e is a 5 coaxial cable having an inner conductor and an annular UNITED STATES PATENTS wall of insulation between said inner conductor and said 2 793 113 7 1957 11 et aL 17 75 conducting member and said inner tube is inserted over 2,929,862 3/1960 Anne et aL said wall. a

5. The termination of claim 4 wherein said outer tube DARRELL L7 CLAY Prim-my Examiner is compressed in the shape of a regular polygon.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,349,165 October 24, 1967 Arie Zimmerman It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

p In the heading to the printed specification, lines 3 to 5, for 0 Anaconda Wire and Cable Co., 605 3rd Ave. New York,

N. 'Y. l0016)"read assignor to Anaconda Wire and Cable Company, a corporation of Delaware column 2, line 49, after "have" insert invented Signed and sealed this 17th day of December 1968.

(SEAL) attest:

Edward M. Fletcher, Jr. EDWARD J. BRENNER lttesting Officer Commissioner of Patents

Claims

1. A TERMINATION IN A CABLE HAVING A TUBULAR CONDUCTING MEMBER AND AN INSULATING JACKET SURROUNDING SAID MEMBER AND BONDED THERETO, COMPRISING: (A) A UNITARY CONDUCTING FERRULE COMPRISING INNER AND OUTER CONCENTRIC TUBES CIRCUMFERENTIALLY JOINED AT ONE END, (A) THE INNER OF SAID TUBES BEING SUBSTANTIALLY LONGER THAN THE OUTER OF SAID TUBES, (B) SAID INNER TUBE BEING INSERTED DIRECTLY UNDER SAID CONDUCTING MEMBER, AND (C) SAID OUTER TUBE BEING APPLIED OVER SAID JACKET, (D) SAID OUTER TUBE BEING COMPRESSED THEREBY LOCKING SAID FERRULE ONTO SAID CABLE AND GROUNDING SAID CONDUCTING MEMBER.