US3599171A

US3599171A - Ignition cable connector

Info

Publication number: US3599171A
Application number: US777562A
Authority: US
Inventors: Arnold E Anderson
Original assignee: Ford Motor Co
Current assignee: Ford Motor Co
Priority date: 1968-11-21
Filing date: 1968-11-21
Publication date: 1971-08-10
Anticipated expiration: 1988-08-10

Abstract

The disclosure relates to a dependable electrical termination for a high-voltage, low-current insulated electrical conductor, i.e., an ignition cable and to the process of making the electrical termination. The termination comprises a metallic staple, preferably of U-shaped construction, which is driven through the insulating sheath of the ignition cable into firm electrical contact with a central current-carrying member of the nonmetallic type. The plane of the metallic staple is approximately parallel to the central current-carrying member, and the central portion of the staple is exposed. A conductive cylinder or ferrule is positioned over the end of the ignition cable and in electrical contact with the exposed central portion of the staple.

Description

United States Patent i72| lmentor Arnold E. Anderson Livonia. .Nlich. 2|| Appl No 777,562

II} riled N0\.Zl.l968 [HI Patented Aug, 10. 1971 l" Assignee Ford Motor Company Dearborn, Mich. Continuationimparl of application Ser. No. 504.503. Oct. 24. 1965. now abandoned.

{Hi IGNITION CABLE CONNECTOR 4 Claims 2 Drawing Figs.

(I L .S.Cl. .w t 339/97 C, Bis/663381214. 339/223 S (51] lnt.Cl. HOlrll/ZO 0] FieldofSearch H 339/97- H61 References Cited UNITED STATES PATENTS 2.389255 ll/l945 Graham l 339/98 2.970,l84 H1961 Blonder l l 4 4 l74/B8 3,284.75] [H1966 Barkeret al. 8 66 1457.359 7/l969 Soucy 4 4 l 4 l l 174/4 Primary Examinerjames Av Leppink Assistant Examiner-Joseph Hv MCGlynn .4t1orney.\-John R. Faulkner and Keith L. Zerschling ABSTRACT: The disclosure relates to a dependable electrical termination for a high-voltage, Iow-current insulated electrical conductor, i.e., an ignition cable and to the process of making the electrical termination. The termination comprises a metal lic staple. preferably of U-shaped construction, which is driven through the insulating sheath of the ignition cable into firm electrical contact with a central current-carrying member ofthe nonmetallic type. The plane of the metallic staple is ap proximately parallel to the central current-carrying member, and the central portion of the staple is exposed A conductive cylinder or ferrule is positioned over the end of the ignition cable and in electrical contact with the exposed central portion of the staple.

IGNITION CABLE CONNECTOR This application is a continuation-in-part of application Ser. No. 504,503 filed Oct. 24, 1965, and now abandoned in the name of Arnold E. Anderson and assigned to the assignee of this invention.

BACKGROUND OF THE INVENTION This invention relates generally to the field of terminations for electrical conductors and, more particularly, to an electrical termination for an ignition cable employing a nonmetallic current-carrying member enclosed in an insulating sheath and to the method of making the electrical termination.

Nonmetallic current-carrying conductors enclosed in insulating sheaths have been employed in the automobile industry as ignition cables for a considerable period of time. This type of ignition cable is known as a resistance cable and reduces electrical radiations that will interfere with the operation of radios and television sets. These ignition cables present a considerable problem from the standpoint of providing proper dependable terminations so that they may be connected to the distributor, spark plugs and the ignition coil of an internal combustion engine. This is particularly true where the nonmetallic current carrying member comprises a particulate carbonaceous material that is impregnated within-an insulating carrier, for example, parallel glass fiber filaments. It is essential in these terminations that the carrier not be disturbed to the extent that the particulate carbonaceous material becomes dislodged from the carrier. If this happens, arcing will occur at the termination and degradation of the termination occurs to the extent that it will no longer properly carry the required voltage and current necessary for satisfactory operation of an ignition system.

The present invention remedies the above-mentioned difficulties by providing an inexpensive and very reliable termination for the end of an ignition cable.

SUMMARY OF THE INVENTION The present invention relates to an electrical termination for the end of an ignition cable having a nonmetallic currentcarrying member enclosed in an insulating sheath and to a method of making this termination. A substantially U-shaped metallic staple having a pair of spaced, generally parallel leg portions joined by a central portion is driven through the insulating sheath and into the nonmetallic current-carrying member leaving the central portion of the staple exposed. The plane of the staple is approximately parallel to the central nonmetallic current-carrying member to provide a surface for an electrical connection to a conductive cylinder or ferrule that is positioned over the insulating sheath and in electrical contact with the central portion of the staple. A portion of this conductive cylinder or ferrule extends axially beyond the end of the ignition cable for connection to the ignition components of the internal combustion engine, for example, spark plugs,

distributor caps and ignition coils.

The conductive cylinder or ferrule positioned around the insulating sheath may be crimped radially inwardly into firm engagement with the central exposed portion of the staple and in this process the central portion of the staple may be deformed so that is is in contact with the main body portion of the conductive cylinder or ferrule and with the crimped portion thereof.

The nonmetallic current-carrying member comprising particulate carbonaceous material impregnated in the carrier forms the central portion of the ignition cable. This particular form of nonmetallic current-carrying member is very sensitive to mechanical deformation, since the particulate carbonaceous material may become dislodged from the carrier at the end of the cable thereby causing arcing or sparkling at the termination and further degradation of the cable under operating conditions. It is a further feature of the invention to space the leg of the staple nearest the end of the cable at least one-half of the diameter of the cable from the end so that the FIG. I shows one embodiment ofthe invention designed for use at the spark plug end of an ignition cable.

FIG. 2 shows another embodiment "of the invention designed to be inserted into a spark coil or a distributor cap.

DESCRIPTION OF THE PREFERRED-EMBODIMENT FIGS. 1 and 2 disclose a conventional ignition cable structure 10 with an external insulating sheath 11 and a central current-carrying member 12. This central current-carrying member is a nonmetallic conductor structure and is employed to eliminate radiation from the ignition cables. It may be comprised of a carrier, for example, rubber or glass fibers impregnated with particulate carbonaceous material.

The termination taught in this invention is fabricated by driving the spaced, parallel legs 14: and 16 of a conventional metallic staple 18 through the insulating sheath 11 and at least deep enough to insure a satisfactory electrical contact with the current-carrying member 12. This staple is driven, as shown, with the plane defined by the staple approximately parallel to the central current-carrying member. The drawings depict the

staple legs

14 and 16 after they have been driven through and past the central current-carrying member 12. This depth of penetration is satisfactory, and is greater than is ordinarily necessary. The central portion 20.0! the staple 18 that is integrally joined with spaced, parallel:

legs

14 and 16 and positioned substantially perpendicular to them is exposed at the outer periphery of the insulating sheath 11.

In FIG. 1 there is shown a generally cylindrical electrical conductive member 22, which may be a ferrule, positioned over the end of the ignition cable 10. This ferrule or cylindrical conductive member 22 has a main body portion 24 that has an inside diameter substantially equal to the outer diameter of the ignition cable 10 and it is positioned over the end of the cable after the staple 18 has been driven into the cable as explained above. It also has an intermediate portion 26'of enlarged diameter and spaced from the end 28 of the ignition cable 10 in an axial'direction to provide a means for attaching or affixing the cylindrical conductive member or ferrule 22 to a spark plug terminal ofcomplementary shape. The main body portion 24 may be crimped radially, inwardly to form a portion of smaller diameter shown at 30 so that it engages the central portion 20 of the staple 1%. This crimping operation may deform the end portion of the central portion 20 of staple 18 radially inwardly as shown in FIG. 1 so that the central portion is in engagement with the generally cylindrical conductive member or ferrule 22 throughout the length of central portion 20 of the staple 18. The deformation of the central portion 20 of the staple 18 may occur because the crimped portion 30 also engages the end ofleg 14 of staple 18.

FIG. 2 discloses a termination suitable for use in connecting the end of the cable 10 to a distributor or spark coil. In this case, the cylindrical conductive member or ferrule 22 has an inner diameter substantially equal to the outer diameter of the ignition cable 10 and is positioned over the end of the cable so that the main body portion 24 of the conductive cylindrical member or ferrule 22 engages the central portion 20 of the staple 18. The main body portion 24 ofthe ferrule or cylindrical conductive member 22 extends axially from the end 28 of the cable 10 and has a flat plate 31. positioned generally perpendicular to the axis of the cable This plate is formed integrally with the main body portion 4 by means of an annular enlarged portion 32. A central aperture 34 may be formed in the flat plate 31 to receive a locating and conductive pin positioned in a distributor cap or ignition coil.

The generally cylindrical conductive member 22 may be formed from flat plates of conductive material positioned in a fixture together with the end of the ignition cable 10 after the staple 18 has been driven. This fixture with a pair of cylindrical dies shapes the flat plates into cylindrical form around the end of the ignition cable and into contact with the central portion of the staple 18. In addition, these dies may perform the crimping operation described in relation to FIG. 1.

As stated previously, the current-carrying member 12 may be comprised of a carrier, for example, glass fibers or rubber impregnated with particulate carbonaceous material. It is important in these circumstances that the leg 16 of the staple 18 adjacent the end 28 of the cable be spaced at sufficient distance from this end to prevent particulate carbonaceous material impregnated within the carrier from being mechanically dislodged from the carrier. In order to achieve this purpose, the leg 16 of the staple 18 should be spaced from the end 28 of the cable distance at least one-half the diameter of the cable. It has been found in practice that this particular spacing provides a very satisfactory termination.

The present invention thus provides a very reliable and inexpensive termination for an ignition cable and a very uncomplicated method of constructing the termination.

The invention disclosed will have many modifications which will be apparent to those skilled in the art in view of the teachings of this specification. It is intended that all modifications which fall within the true spirit and scope of this invention be included within the scope of the appended claims.

What I claim is:

1. An electrical termination comprising an ignition cable having a central nonmetallic current-carrying member enclosed in an insulating sheath, a substantially U-shaped metallic staple having a pair of spaced generally parallel leg portions joined by a central portion, said legs extending through said insulating sheath and into said central nonmetallic currentcarrying member adjacent the end of said ignition cables, said central portion extending outwardly of said insulating sheath, the plane of said staple being approximately parallel to said central nonmetallic current-carrying member, a conductive generally cylindrical-shaped member positioned over said insulating sheath and having an inwardly extending crimped portion positioned in electrical contact with said central portion of said staple, a portion of said conductive generally cylindrical-shaped member extending axially beyond the end of said ignition cable.

2. The combination of claim 1 in which said nonmetallic current-carrying member comprises particulate carbonaceous material impregnated in a carrier constructed of insulating material, and the leg of the staple nearest the end of the cable is positioned at least one-half the diameter of tee cable from said end.

3. The combination of claim 1 in which said central portion of said staple has a deformed radially inwardly extending por tion extending over a part of its length positioned in electrical contact with said inwardly extending crimped portion of said generally cylindrical-shaped member, the remainder of said central portion being positioned in electrical engagement with said generally cylindrical-shaped member.

4. The combination of claim 3 in which said nonmetallic current-carrying member comprises particulate carbonaceous material impregnated in a carrier constructed of insulating material and the leg of the staple nearest the end of the cable is positioned at least one-half the diameter of the cable from said end.

Claims

1. An electrical termination comprising an ignition cable having a central nonmetallic current-carrying member enclosed in an insulating sheath, a substantially U-shaped metallic staple having a pair of spaced generally parallel leg portions joined by a central portion, said legs extending through said insulating sheath and into said central nonmetallic current-carrying member adjacent the end of said ignition cables, said central portion extending outwardly of said insulating sheath, the plane of said staple being approximately parallel to said central nonmetallic current-carrying member, a conductive generally cylindricalshaped member positioned over said insulating sheath and having an inwardly extending crimped portion positioned in electrical contact with said central portion of said staple, a portion of said conductive generally cylindrical-shaped member extending axially beyond the end of said ignition cable.

2. The combination of claim 1 in which said nonmetallic current-carrying member comprises particulate carbonaceous mateRial impregnated in a carrier constructed of insulating material, and the leg of the staple nearest the end of the cable is positioned at least one-half the diameter of the cable from said end.

3. The combination of claim 1 in which said central portion of said staple has a deformed radially inwardly extending portion extending over a part of its length positioned in electrical contact with said inwardly extending crimped portion of said generally cylindrical-shaped member, the remainder of said central portion being positioned in electrical engagement with said generally cylindrical-shaped member.