US2911459A

US2911459A - Terminal for shielded conductors

Info

Publication number: US2911459A
Application number: US553303A
Authority: US
Inventors: Ernest R Haberland
Original assignee: Hughes Aircraft Co
Current assignee: Raytheon Co
Priority date: 1955-12-15
Filing date: 1955-12-15
Publication date: 1959-11-03
Anticipated expiration: 1976-11-03

Description

Nov. 3, 1959 E. R. HABERLAD-- 2,911,459

TERMINAL FOR SHIELDED CONDUCTORS Filed Deo. 15, 1955 y Ml.

nited States Patent l t 2,911,459 TERMINAL non SHIELDED coNDUcToRs .Ernest R. Haherland, Los Angeles, Calif., assignor to HughesAircraft Company, Culver City, Calif., a corporation of Delaware Application December 15 A195.5, Serial No. 553,303

i '2 Claims. .(Cl. v1`74-75)y The present invention relates generally to terminals for conductors and relates more specically to a terrule type terminal arrangement adapted for use in providing termination' for shielded conductors andV a means for securing a grounding wire to shielding.

l Heretofor'e conductor shielding termination has been providedby dressing `a conductor to a proper length, un-

y' raveling the strandedshie'lding therefrom for a distance v of approximately two inches, then twisting the unraveled Shielded material together toform the equivalent of a single stranded conductor'. Thereafter 'the central wire of a grounded lead conductor was twisted with the stranded shielded material and the connection was soldered. Additionally, it was necessary to then dress the solder joint for length, fold it back to overlie `the shield braid and apply an insulatingsleeve over the completed terminationl'. This prior method was not only extremely time.

consuming and costly but involved a considerable amount of hand labor in unraveling'the conductor braid shielding, twisting, soldering, etc. lUnless extreme care wasv taken in the soldering operation, the heat involved would .deteriorate the insulation on the wire conductor andk create a termination that was not satisfactory for the purposes intended. Furthermore, .unavoidably broken strands, of the shield material, as a result of the unraveling operation; had atendency to pierce the heat deteriorated insulation, thus resulting in undesirable, actual Y Ior: potential short circuits.

In other instances, this prior method of establishing shielded conductor termination has been unsatisfactory where high voltage shielded conductors were-used, inasmuch as abrupt termination of shielding creates an area of high electric field concentration which tends to cause premature insulation failure.

Y It is, accordingly, one important object Vof the present invention to provide 'al novel shielded conductor terminal construction.

y It is another important object of the present invention to provide a novel'termina'tion ferrule for shielded conductors that may be rapidly applied without the use of heat or solder. Y.

v It is a further Iimportant object of this invention to l provide a terminal ferrule adapted for use with shieldedaccompanying drawing, wherein:

Figure 1 is an exploded perspective view of the present y, terminal arrangement;

2,911,459' Patented Nov. 3, 1959 Fig. 2 is a perspective view showing the various components hereof in an assembled condition prior to crimping thereof; n K

Fig. 3 is a further perspective view showing the terminal constructionin an assembled and crimped condition;

Fig. 4 is a longitudinal sectional View taken substantially as indicated by line `1 -4, Fig. 3; and

Fig. 5` is a perspective view showing one form of Ytool that may be employed for crimping the present terminal.

With reference to the drawing, and with reference primarily to Fig. l, the ferrule arrangement hereof is v adapted for use with a shielded type conductor indicated generally at 10. Conductors of-this type comprise a central metallic wire portion 11 having suitable insulation 12 thereabout and braided metallic shielding 13 positioned about the insulation 12. As discussed hereinbefore, it.

.has been the prior practice to unravel the braided shielding, twistthe unraveled strandstogether and provide a grounding connection. In this instance, the shielding 13 is trimmed back from an endv of the insulation 12 whereby to expose a length of this insulation.

The terminal fitting of this invention is shown as indicated generally at 15 and includes a cylindrical body portion 16 and an integral en d wall portion 17. The cylindrical portion 16 and the end wall portion 17 are joined as by a relatively large radius section 18. An elongated tubular portion 20 is integrally formed axially from the end wall portion l17 and` extends through, within the contines 'of and beyond a free .edge 21 of the cylindrical portionl. As shown primarily in Figs. l and 4, the tubular portion 2l) Vis joined integrally with the end wall portion 17V by means of a preformed annular ared portion 22for a purposeto be hereinafter more fully described. The tubular portion 2li` is further provided with4 an axial bore 23 therethrough.

In order to aid in the crimping of the cylindrical portion 16vand provide an outlet for a grounding lead indicatedgener'ally at 24, the terminal ferrule 15 is provided with a longitudinally extending V-shaped notch 25, the open end of which communicates with the free edge 21 of the cylindrical portion 16. Specifically, the grounding lead 24 includes a central wire portion 26 having insulation27 thereon. The insulation 27 is removed from a portion of the-wire 26 and the exposed Wire end is suitably bent as shown in Fig. A1.

With referenceto Fig. 2, it may be seen that the tubular portion 20 of the terminal ferrule 15 is positioned on the insulation 12 of thel conductor 10 and inserted between :this insulation and then braided metallic shielding 13. Thereafter, the wire portion 26 of the grounding conductor 24 is wrapped about the outer surface of the shielding v13 overlying the tubular portion 20 of the'terrninal ferrule 15. The free end'o'f the braided shielding 13 is pushed into contact with the end wall 17 of the termination Aferr'ule and is permitted to fold or bunch. back upon itself and against this end wall. ,y l f After positioning the various components of the present terminal arrangement as shown in Fig. 2, the cylindrical portion 16 and the free end 21thereof is crimped radially inwardly, with the wire portion 26 of the grounding lead 24 being permitted to extend therefrom through the V-shaped notch 25, thus creating not only a compact termination arrangement for the shielding 13, but also providing an adequate connection between the grounding lead 24 and the shielding. The crimping of the cylindrical portion 16 of the terminal ferrule 15 radially inwardly is limited in this radial inward movement thereof by reason ofthe position of the tubular portion 20 beneath the braided shielding 13, thus to prevent.

any damage to either the insulation 12 of the conductor 10 or the wire portion 11 thereof. Additionally, as shown primarily in Fig. 4, the end wall 17 of the ter- 'The recesses are split half sections, each comprising outer

semicircular portions

32 and 33 which cooperate respectively with a portion of the shielding 13 overlying the tubular portion 20 and the insulation 12. A suitably rounded semicircular portion of the recesses is indicated at 34 and positioned between the

portions

32 and 33.

The portion 34 is of a general conguration commen-f surate with the -desired ultimate shape of the crimped terminal ferrule. One edge of each of the portions 32 is notched as at 35 to permit space for the lead wire 26 when the ferrule is crimped and to prevent damage to this lead.

It may thus be seen that the present terminal ferrule v is an integral unit, provides for more adequate electrical connection, is easily installed and formed and is considerably less expensive in manufacture and installation than heretofore known multiple component structures designed for similar purposes. Additionally, the particular iconfiguration of the completed terminal end is such as to reduce electrical corona eiects, prevent deterioration of the insulation and/ or inadvertent cutting or compression thereof. from any suitable metallic material such as, for example, soft ductile brass, thus reducing the possibility of pinching the grounding conductor wire 26 and enabling proper forming about the bundled end of the shielding 13 and about the wire portion 26. Actually, it is not necessary for any of the components utilized herein to be soldered after assembly is made and the condition shown in Fig. 3

is established. However, if it is desired, little or no problems exist as to the application of a small amount of solder in the area of the terminal ferrule 15 and grounding wire lead 26.

In still another instance, it is to be noted that since the braided material of the shielding 13 is not unraveled but is confined within the terminal ferrule 15, little or no possibility exists that broken shield strands will cause undesirable short circuits that may be detrimental to anyl components with which the present arrangement is utilized. Additionally, the conductor central wire 11, together with the insulation 12 carried thereby, is free to slide through the shield termination and specifically through the bore 23 of the tubular portion 20.

Having thus described theinvention and the present embodiment thereof, it is desired to emphasize the fact that many modillcations may be resorted to in a manner limited only by a just interpretation of the following claims.

What is claimed is:

The terminal ferrule 15 may be made 1. In a termination ferrule vfor a shielded electrical conductor, the combination of: a generally cylindrical body portion having a substantially annular free edge; an integral radially disposed end wall for said body portion, said end wall being formed about a radius disposed from a circular axis, said radius being tangent to an inner annular surface of said body portion; an elongated tubular portion integrally disposed from said end wall and extending through said cylindrical body portion and beyond said free edge thereof; an annular integral llared portion positioned ata junction of said end `wall and said tubular portion; and a longitudinally disposed V-shaped notch in saidbody portion, said tubular portion being adapted for disposition about insulation and beneath shielding carried' by said conductor, said body portion being crimped radially inwardly to close edges of said V-shaped notch and provide engagement between said free edge of said body portion and an outer area of said shielding overlying said tubular portion, said flared portion serving to provide a gradual approach of said end wall before contact of said ferrule with said insulation.

2. In a termination ferrule forV a shielded electrical conductor, the combination of: a generally cylindrical body portion having a substantially annular free edge; an integral radially disposed end.wall for said body portion, said end wall being formed about a radius disposed from a circular axis, said radius being tangent to an inner annular surface of said body portion; an. elongated reduced diameter tubular portion integrally disposed from said end wall spaced from and extending through said cylindrical body portion and beyond said free edge thereof; an annularintegral flared portion positioned at a junction yof said end wall and said tubular portion; and a longitudinally disposed V-shaped notch in said body portion, said tubular portion being adapted for disposition about insulation and beneath shielding carried by said conductor, said body portion being crimped radially inwardly to close edges of said V-shaped notch and provide engagement between said free edge of said body portion and an outer area of said shielding overlying said tubular portion, said ilared portion serving to provide a gradual approach of said end wall before contact of said ferrule with saidA insulation, said ferrule being also adapted for reception of a shielding grounding connector within confines thereof and extending outwardly through said V-shaped notch.

References Cited in the file of this patent UNITED STATES PATENTS 1,941,614 Meyer et al. Jan. 2, 1934 2,694,183 Elden et al Nov. 9, 1954 FOREIGN PATENTS 102,137 Great Britain Nov. 13, 1916 OTHER REFERENCES Publication I, Grounding Shielded Cable (Manzi et al.), published in Electrical World, December 1942. (Pages 12S-130 relied on.)