US3517375A - Crimping terminal for coaxial cable - Google Patents

Description

June 23, 1970 I MANCINI 3,517,375

CRIMPING TERMINAL FOR COAXIAL CABLE Filed Jan. 29, 1968 5A/////////////A Uk A INVENTOR LLOYD MANCINI United States Patent O 3,517,375 CRIMPING TERMINAL FOR COAXIAL CABLE Lloyd Mancini, New Cumberland, Pa., assignor to Berg Electronics, Inc., New Cumberland, Pa., a corporation of Pennsylvania Filed Jan. 29, 1968, Ser. No. 701,356 Int. Cl. H01r 17/18 U.S. Cl. 339-177 17 Claims ABSTRCT OF THE DISCLOSURE A crimp type terminal and method for forming an electrical connection with the cylindrical sleeve or shield of a coaxial cable. When crimped to a bared braided sleeve the terminal collapses a medial portion `thereof to form an annular collar. The terminal is crimped to the collar to establish an electrical connection.

BACKGROUND OF THE INVENTION Conventionally electrical connections are established with coaxial cable braid by means of a solder connection or by inserting a iirst crimping sleeve under an end of the braid, positioning a second crimping sleeve over the braid, and then crimping the sleeves together to sandwich the braid therebetween.

A solder connection with the braid requires removal of a portion of the braid `from the cable to form a pigtail for physical connection with a wire or terminal, following which the joint is soldered. This type of connection is time-consuming to make and often results in an imperfect electrical connection between the terminal and the braid. Likewise the concentric sleeve type connection is expensive in terms of labor cost since the sleeves are positioned manually on the cable and then crimped together. Examples of conventional electrical connections for Ibraid are shown in Manzi, Marsman & Brenner, Grounding Sheathed Cable, pp. 128-130, Electrical Manufacturing, December 1952.

SUMMARY OF THE INVENTION The invention relates to a crimp type terminal and method for establishing an electrical connection with a wrapped or braided sleeve. The terminal is applied to a bared portion of the sleeve so that it grips the sleeve at spaced locations and is then collapsed axially to collapse the medial portion of the sleeve and form an outwardly projecting double thickness collar of sleeve material. A portion of the collapsed terminal is crimped to each side of the collar to establish the electrical connection. The terminal may be provided with a contact portion for establishing anelectrical connection with a circuit element.

The crimping terminal according to the invention is easily and quickly applied to the sleeve and forms a reliable electrical connection therewith without the necessity of manual assembly or a soldering operation. When the terminal is used to establish an electrical connection with the sleeve at an end of the coaxial cable, the free end of the sleeve is moved axially away from the end of the cable during attachment of the terminal so as to prevent accidental short circuiting between the axial conductor and the sleeve.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a terminal according to the invention;

FIG. 2 is a perspective view of the terminal of FIG. 1 attached to a bared end of a braided conductor of a clzyoaxial cable prior to collapsing of the terminal and raid;

Patented June 23, 1970 FIG. 3 is similar to FIG. 2 with the terminal and braid collapsed;

FIG. 4 is a sectional view taken along line 4-4 of FIG. 3;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 4;

FIG. 6 is a perspective view of a modified terminal for attachment to the braid conductor of a coaxial cable; and

FIG. 7 is a side view showing the terminal of FIG. 6 secured to the braid.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Elongate U-shaped crimping terminal 10 is formed from sheet metal stock and includes a pair of spaced U-shaped crimping barrels 12 and 14 joined together by a plurality of outwardly bent leg portions 16 which are spaced around the periphery of the terminal. Axially opposed contact ilanges 18 extend outwardly of the adjacent edges of barrels 12 and 14 and are inclined toward each other to improve contact with the braid. Braid gripping teeth 20 are provided on the interior surface of each barrel 12 and 14 adjacent the leg portions 16. As indicated most clearly in FIG. 4, the teeth 20 have a braid gripping face 21 for preventing movement of the braid relative to the barrel during collapsing of the terminal. Teeth 20 may be formed from the metal stock of the barrels 12 and 14 by a punching operation which also forms recesses 22 on the outer surface of the barrels. A suitable contact means 23, such as a pin disconnect, may be provided in order to establish an electrical connection between the terminal 10 and a circuit element.

The terminal is useful in establishing an electrical connection with a bared portion of the shield or braided sleeve conductor conventionally used in a coaxially cable 24 of the type shown in FIG. 2, having an inner or axial conductor 26. A pair of dielectric spacers 28 are wound around the conductor 26 in the form of helixes to locate the conductor centrally within the bore of cylindrical insulator 30. Flexible sleeve or ground conductor 32 encases the insulator 30 so as to prevent external elds from affecting the si-gnal carried by cable 24. An outer insulating sheath 34 may be provided. Spacers 28 are used to locate the central conductor 26 accurately relative to the insulator 30 and sleeve 32 in order to maintain a desired impedance for the cable.

The sleeve 32 surrounds the dielectric material 30 rather loosely to permit ready bending of the cable. It may be woven from groups of exible conductor strands to form a loose mesh braid as shown in the drawings, or may be formed from flexible conductor strands which are wound around the dielectric insulator 30 to form a sheath. In the latter case it is desirable that the cable be provided with an outer insulator 34 to conline the wound conductor strands and prevent unraveling of the sleeve. The terminal described herein is effective in establishing an electrical connection with either a woven or Wound sleeve. While two forms of coaxial cable shielding have been disclosed, the invention is not limited by the type of sleeve to which the terminal is secured. The terminal may be used to establish an electrical connection with collapsible conductive cylindrical sleeves other than the two forms mentioned. While the invention is particularly useful in establishing an electrical connection with the outer conductor of a coaxial cable, it is not intended to be limited to that use. It can be used wherever it is desirable to form an electrical connection with a flexible sleeve conductor.

Because sleeve 32 is used as one of the two conductors of the coaxial cable 24, it is necessary to form an electrical connection with the sleeve at the end of the cable.

3 To establish a connection -between a terminal and the end of the conductive sleeve of cable 24, a portion of the insulation 34 is removed from the end of the cable 24 a distance slightly -greater than the length of the terminal 10. The terminal is then placed around the exposed braid of sleeve 32 and barrels 12 and 14 are crimped closely to a generally circular cross section so that the teeth 20 engage the braid and prevent movement of the braid relative to the barrels. The terminal is then secured to the cable as illustrated in FIG. 2.

After the terminal is crimped to braid 32, the bar- Iels 12 and 14 are moved together to collapse the interconnecting leg portions 16 and to collapse the medial portion 36 of the braid 32 located between barrels 12 and 14. As the barrels are moved together the sheath collapses to form a double thickness annular collar 38 `which is confined between opposite straight leg portions 40 of the legs 16. Before collapsing of the legs 16, portions 40 in each leg define an obtuse angle. When the terminal is fully collapsed as in FIG. 4, the portions 40 are generally parallel to each other and sandwich the collar 38 therebetween to establish an electrical connection.

Upon movement of the barrels 12 and 14 toward each other, the medial portion 36 of the cylindrical sleeve 32 is readily collapsed to form the double thickness collar 38. During collapsing of the terminal and sleeve the teeth 20 in each barrel 12 and 14 engage the sleeve and prevent it from slipping relative to the barrels so as to assure that the medial portion 36 is collapsed to form collar 38.

During collapsing of the terminal and sleeve the medial portion 36 is rst bowed outwardly of the cable so that as the inclined flanges 18 are brought together they engage the sleeve 32. With further collapsing of the terminal and sleeve, flanges 18 tightly sandwich the collar 38 and are bent back from their original position. The bending of the flanges 18 during collapsing of the terminal assures that the collar 38 is yconfined therebetween under spring tension and improves the electrical connection between the flanges and the collar. In the collapsed terminal 10, barrels 12 and 14 are held closely together by legs 16 so that the flanges 18 establish an electrical connection with the collar 38.

An electrical connection between the terminal 10 and the sleeve 32 is established at each of the leg portions 16 and at each adjacent pair of flanges 18. As shown in FIG. 5, the flanges and legs of the terminal are spaced around the circumference of the cable 24 so that the terminal forms an electrical connection with the sleeve around essentially its entire circumferential extent. This is an important feature since it is desirable that the entire sleeve fonm part of the circuit in order to attain desired impedance and shielding. If a single connection is established with one circumferential portion of the sleeve, there is no assurance that the connection will place the entire sleeve at the same potential since the sleeve comprises a plurality of conductors which are not directly connected to one another. Terminal 10 insures that a reliable electrical connection is established with essentially all of the conductors in sleeve 32.

Because the electrical contacts between the sleeve 32 and terminal 10 are formed in a radial plane and the contact forces establishing these connections are essentially axial, the radial geometry of the cable 24 is not substantially distorted by. the attachment of the terminal to the cable. In this way the terminal 10 affects the impedance of the cable 24 to a minimum extent. When the terminal is crimped to the cable the opposing edges 42 of the barrels 12 and 14 are brought into contact to assure that teeth 20 rmly seat in the sleeve 32. When the crimping force is removed, the barrels relax slightly and the edges 42 separate to a slight degree. Crimping of the terminal on the cable results in a slight compression of dielectric insulator 30 as indicated in FIG. 4. Such distortion does not result in appreciable changes in impedance. In conventional crimp type connectors for establishing contact with the sleeve of a coaxial cable, :the electrical connection is formed as the result of a radial force likely to greatly distort the geometry of the cable and change the impedance of the cable.

As the terminal is collapsed the free end 44 of sleeve 32 is moved axially away from the free end of the cable 24 as a result of the shortening of the sleeve when the collar 38 is formed. By moving the sleeve 32 away from the end of the cable, the likelihood of short circuits occurring between the sleeve and axial conductor 26 is reduced. This feature of the invention is important since it eliminates the necessity of checking each terminal when attached to a braid to be certain that there is no accidental short circuiting between the sleeve and the central conductor as a result of unraveling of the sleeve.

FIG. -6 illustrates a terminal 50 comprising an arcuate U-shaped crimping 4'barrel 52 with a portion 54 extending therefrom. The barrel 52 may be tted over a part of an annular collar 56 formed in a conductive sleeve 58 of coaxial cable 60. The barrel 52 is then crimped to bring side or leg portions 62 thereof into intimate contact with the collar to establish an electrical connection therewith. A circuit element may be attached to a contact on portion 54.

Terminal 50 is mounted directly on the annular collar 56 formed in the sleeve of cable 60 and does not touch the body of the cable. Thus terminals 50 may be used in situations where it is highly desirable that the impedance of the cable not be affected at all by terminals secured to the conductive sheath.

While I have illustrated and described preferred embodiments of my invention, it is understood that these are capable of modification and I therefore do not 4wish to be limited to the precise details set forth.

What I claim as my invention is:

1. A terminal for establishing an electrical connection with a flexible conductive sleeve, comprising an axially collapsible terminal body adapted to ibe mounted on said sleeve in surrounding relation thereto and having portions at each end therefor engageable with said sleeve to prevent relative movement therebetween, collapsible leg means joining said terminal portions to permit movement of said terminal portions and the engaged portions of the sleeve toward each other to bunch a medial portion of the sleeve into an annular outwardly projecting collar, and contact means on said terminal portions adapted to engage and establish an electrical connection with said collar.

2. A terminal according to claim 1 wherein said terminal portions are adapted to be crimped to said sleeve and are provided wtih means thereon engageable with said sleeve to prevent relative movement between said terminal portions and said sleeve when said terminal body is collapsed.

3. A terminal according to claim 1 including a plurality of said contact means on each of said terminal portions with each contact means axially aligned with one of the contact means on the other terminal portion.

4. A terminal according to claim 3 wherein said contact means are adapted to establish said electrical connection with substantially the entire circumferential extent of said collar.

5. A terminal according to claim 3 wherein said contact means comprise flanges projecting outwardly of said terminal portions at spaced intervals along the opposing edges of said terminal portions.

6. A terminal according to claim 3 wherein said leg means comprise a pair of integral angularly related legs extending from said terminal portions and adapted to be bent outwardly into generally parallel relation as said terminal body is collapsed to sandwich said collar therebetween to provide said electrical connection.

7. A terminal according to claim 6 wherein a plurality of said leg means are spaced along and extend from the opposing edges of said terminal portions.

8. A terminal according to claim 7 including opposed pairs of anges projecting outwardly from said terminal portions, each pair of flanges being disposed between adjacent pairs of said leg means and adapted to sandwich said collar therebetween to establish an electrical connection therewith.

9. An electrical contact system comprising a cable having a conductive sleeve surrounding a cylindrical insulator, an annular collar formed from a collapsed medial portion of said sleeve with parts of said sleeve extending axially along the cable to either side of said collar, said collar comprising a pair of flattened sleeve portions, each of which extends circumferentially around said insulator and projects radially outwardly therefrom, and a circumferential bight portion joining said attened portions outwardly of said insulator, the inner surfaces of said attened portions abutting each other at an interface, and a terminal crimped to the opposite sides of said collar to sandwich said collar between opposing terminal portions and establish an electrical connection between the terminal and the sleeve.

10. An electrical contact system as in claim 9 wherein said contact means comprises a plurality of U-shaped legs joining said terminal portions and engaging opposite sides of said collar, said terminal portions extending around said sleeve and being crimped thereto, gripping means on the inner surface of said terminal portions to prevent axial movement of said portions relative to said sleeve, and flange means extending outwardly of each of said terminal portions adjacent said collar and located between adjacent legs on each terminal portion, said flange means being biased into engagement with said collar to establish an electrical connection therewith.

11. An electrical contact system as in claim 9 wherein said terminal is disposed in surrounding relation to said sleeve and includes portions on each side of said collar physically engaging said sleeve to prevent relative movement therebetween, and contact means extending outwardly from said portions in electrical contact with said collar.

12. An electrical contact system as in claim 11 wherein said contact means comprises a U-shaped leg joining said terminal portions and engaging opposite sides of said collar.

13. An electrical contact system comprising a exible conductive sleeve, a double thickness medial portion of said sleeve extending circumferentially around said sleeve and projecting radially outwardly therefrom to form a at radial collar, and a terminal disposed in surrounding relation to said sleeve, said terminal including portions on each side of said collar crimped to said sleeve, said portions including gripping means on the inner surfaces thereof to engage said sleeve and prevent axial movement relative thereto, and contact means extending outwardly from said portions adjacent said collar for electrical contact with said collar.

14. A method of forming an electrical connection between a terminal and a collapsible cylindrical conductive sleeve comprising the steps of axially collapsing a medial portion of the sleeve to form a double thickness annular collar extending radially outwardly from the sleeve and circumferentially around the sleeve with the sides of the collar flat against each other and cylindrical portions of the sleeve extending axially to either side of the collar, positioning portions of a terminal to each side of the collar, crimping the terminal to the collar to sandwich the collar between said portions of the terminal and establish electrical connections between the terminal and both sides of the collar.

15. A method for forming an electrical connection with a collapsible conductive sleeve comprising the steps of crimping spaced portions of a terminal to the sleeve and moving such portions together to collapse the medial portion of the sleeve between said portions and form a double thickness annular collar, and securing a portion of the terminal in electrical connection with both sides of the collar.

16. A method of forming an electrical connection between an electrical terminal and a ilexible conductive sleeve which comprises placing the terminal on the sleeve in surrounding relation thereto, engaging axially spaced portions of the terminal with corresponding portions of the sleeve, moving said portions of the terminal and sleeve toward each other to bunch a medial portion of the sleeve into an annular outwardly extending collar while at the same time sandwiching said collar between opposed electrical contact means on said terminal portions.

17. A method according to claim 16 including the step of crimping said axially spaced portions of the terminal around said sleeve.

References Cited UNITED STATES PATENTS 2,678,963 5/1954 Everhart 174-48 3,109,052 10/1963 Dumire et al. 174-882 3,141,924 7/1964 Forney 174-75 FOREIGN PATENTS 980,381 1/ 1965 Great Britain.

RICHARD E. MOORE, Primary Examiner lI. H. MCGLYNN, Assistant Examiner U.S. Cl. X.R. 339-276

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