US3771113A

US3771113A - Spring action terminal with locked barrel

Info

Publication number: US3771113A
Application number: US00193247A
Authority: US
Inventors: G Cronce
Original assignee: Eltra Corp
Current assignee: General Cable Industries Inc
Priority date: 1971-10-28
Filing date: 1971-10-28
Publication date: 1973-11-06
Anticipated expiration: 1990-11-06
Also published as: JPS5620672B2; JPS4851278A; CA961131A

Abstract

A spring action terminal for connection to spark plugs made from a single piece of material, which has a locked barrel provided by a detent which also engages the spark plug.

Description

United States Patent [1 1 Cronce Nov. 6, 1973 SPRING ACTION TERMINAL WITH LOCKED BARREL [75] Inventor: Grant Woodrow Cronce, Port,

Huron, Mich.

[731 Assignee: Eltra Corporation, Toledo, Ohio [22] Filed: Oct. 28, 1971 [21] Appl. No.: 193,247

[52] U.S. Cl 339/256 C [51] Int. Cl H0lr 11/22 [58] Field of Search 339/213 S, 217 SP,

339/220 A, 218 S, 223 S, 258 C, 256 C, 26, 143 S, 47 S, 136 C [56] References Cited UNITED STATES PATENTS 3,546,665 12/1970 Zak ..339/256C 3,223,963 12/1965 Rarey 339/223 S X 3,464,368 10/1968 Roberts et al. 339/223 S 2,553,083 5/1951 Elliott 339/256 C FOREIGN PATENTS OR APPLICATIONS 952,423 3/1964 Great Britain 339/258 C ry Ex min r-Ma in Ar mp Assistant Exaininer-William F. Pate, 111 Attorney-D. Henry Stoltenberg [5 7 ABSTRACT A spring action terminal for connection to spark plugs made from a single piece of material, which has a locked barrel provided by a detent which also engages the spark plug.

2 Claims, 4 Drawing Figures PATENTEUNUV 6 I975 INVENTOR.

' GRANT W. CRONCE- .H ATTORNEY j SPRING ACTION TERMINAL WITI-I LOCKED BARREL BACKGROUND OF THE INVENTION With the trend in manufacturing moving toward greater automation, the search for simple, effective terminals has been augmented, particularly terminals for use with ignition equipment in the automotive field. The terminal structure must be such that it can be manufactured in connected form with automatically operated equipment on a mass production line. The ends of the tube of the terminal embracing the contact head of a spark plug must be mechanically interconnected and yet provide springiness for close interconnection while providing an inwardly projecting tab or detent to cooperate with the undercut in the contact head of the spark plug.

It is therefore a principal object of this invention to provide a terminal which is made from a single piece of material in connected form for mass production which has a locked barrel and a tab or detent projecting into the barrel to interlock with the contact head of a spark plug.

Other objects and advantages of this invention relating to the arrangement, operation and function of the related elements of the structure, to various details of construction, to combination of parts and to economics of manufacture will be apparent to those skilled in the art upon consideration of the following description and appended claims, reference being bad to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

DESCRIPTION OF THE DRAWINGS FIG. 1 is an perspective, view of a connected series of terminals as produced on a mass production line.

FIG. 2 is a plan view of the barrel portion of the terminal.

FIG. 3 is an elevational side view partly in section of the barrel portion and FIG. 4 is an elevational end view of the barrel.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, particularly to FIG. 1, a flat ribbon of metal 10 which may be stored in a large reel (not shown) is fed into a stamping machine (not shown) wherein a progressive die stamps the metal ribbon in steps to form a complete terminal T. The terminal T remains in attached condition to the ribbon by tabs t so that it may again be stored on a reel for use in another automatic machine for attachment to wire or wire harnesses which are to be used in connection with the ignition system of an automotive vehicle. These stamping and forming steps on the metal ribbon 10 are old in the art and will not be described in further detail. The complete terminal T includes a ferrule secinternal diameter to fit snugly over the terminal head 7 SP of a spark plug as shown in FIG. 3 to make electrical connection therewith. The fit is such that the barrel is expanded slightly against the springiness of the metal material which has

ends

10 and 12 which overlap each other for about 30 degrees of are as best seen in FIG. 4. The inner end 12 is provided with a longitudinal rectangular aperture 14, the transverse dimension of which is at least twice 'as wide as the transverse dimension of a longitudinal arcuate tang 16 formed interiorly of the outer end 10, the parts being arranged so that the tang 16 extends into the aperture 14 and projects into the barrel B to contact the head SP of the spark plug to prevent disengagement as shown in FIG. 3.

The aperture 14 and the arcuate tang 16 are punched in the ribbon 10 during the forming operation on the dies as shown in FIG. 1. Thereafter, in the final step of the forming process when the

ends

10 and 12 of the barrel position B are overlapped, the arcuate tang 16 is fitted into the aperture 14 so as to project into it at substantially a central location so that end 10 lifts up with spring tension during the fitting on or removal of the barrel B from the terminal head SP. The overlap of the

ends

10 and 12 of the barrel B may be controlled during manufacture by a longitudinal ridge X formed on the inner end 12 and contacted by the end face 10A of the outer end 10 to limit the overlap. There is a relaxation after formation of the barrel, to allow the tang 16 to retreat to its central location in the aperture 14. The arcuate tang 16 contacts the terminal head SP behind its end enlargement. The engagementdisengagement forces may be varied by removing metal at the spring base such as providing an aperture 17 ap' proximately in line with one edge of section C. The arcuate tang 16 when inserted into the aperture 14 acts as a lock to prevent excessive openings of the barrel during a severely abusive removal of the terminal from a spark plug, such as commonly encountered when service mechanics yank the spark plug wire from the spark plug at great angles to the axis of the spark plug.

It will be understood that the ribbon 10 may be provided with protective metal coats or plating such as cadmium or the like as is well known in the art. When the terminal is to be applied to an ignition lead wire, the storage spool for the terminal tape is applied toan automatic machine for this purpose, and the terminals are removed from the tape one by one as used by breaking the connecting tab b between the terminal units.

I claim:

1. A metallic connector for connecting the end of an ignition wire to the rigid head of a spark plug comprising, in combination, a generally cylindrical barrel portion for releasable attachment to said spark plug head, an open ferrule portion for subsequent permanent attachment to said wire end and an intermediate arcuate center section integrally connecting said barrel and ferrule portions, said barrel portion being formed of a single rounded section having its opposed lateral edges overlapping each other to provide a sector of said barrel of double thickness, an aperture extending through the inner lateral overlapped edge having a transverse width of less than the amount of overlap of said edges, a tang extending radially inwardly from the outer lateral overlapped edge of said barrel portion through said aperture and terminating within said barrel interior to provide a biased retaining means for engagement with said spark plug head, the lateral width of said tang being less than said width of said aperture to permit relative movement of said overlapping edges during engagement with said plug as said barrel portion resiliently expands, an axially extending ridge on said barrel portion closely adjacent the outer lateral edge of said overlapped edges to define the maximum permissible overlap of said lateral edges, said ferrule portion including a pair of open arms extending outwardly from a curved base and said intermediate arcuate center secportion.

Claims

1. A metallic connector for connecting the end of an ignition wire to the rigid head of a spark plug comprising, in combination, a generally cylindrical barrel portion for releasable attachment to said spark plug head, an open ferrule portion for subsequent permanent attachment to said wire end and an intermediate arcuate center section integrally connecting said barrel and ferrule portions, said barrel portion being formed of a single rounded section having its opposed lateral edges overlapping each other to provide a sector of said barrel of double thickness, an aperture extending through the inner lateral overlapped edge having a transverse width of less than the amount of overlap of said edges, a tang extending radially inwardly from the outer lateral overlapped edge of said barrel portion through said aperture and terminating within said barrel interior to provide a biased retaining means for engagement with said spark plug head, the lateral width of said tang being less than said width of said aperture to permit relative movement of said overlapping edges during engagement with said plug as said barrel portion resiliently expands, an axially extending ridge on said barrel portion closely adjacent the outer lateral edge of said overlapped edges to define the maximum permissible overlap of said lateral edges, said ferrule portion includIng a pair of open arms extending outwardly from a curved base and said intermediate arcuate center section connecting said barrel and ferrule portions having substantially the same radius of curvature as said barrel portion and said curved base of said ferrule portion.

2. The connector of claim 1 wherein said barrel portion includes an elongate opening positioned substantially in alignment with a lateral edge of said intermediate center section to vary the resiliency of said barrel portion.