Terminal Connector

Abstract

A terminal connector for connecting an electrical cable to the electrode of a spark plug or the like is disclosed wherein the connector has a first portion adapted to be firmly clamped to the cable, and a second portion interconnected to the first portion through a bendable web and adapted to be releasably electrically connected to the electrode.

Description

The present invention relates to a terminal connector for an ignition cable of an internal combustion engine.

It is common practice to use a particular coupling, known as a terminal connector, in the ignition system of an internal combustion engine to mechanically and electrically connect the terminus of an ignition cable emanating from an electrical distributor to an electrode of a spark plug.

Generally, a metal terminal connector of the prior art comprises a portion for clamping the end of an ignition cable, interconnected by a web to an expandable tubular portion for receiving the electrode of the spark plug. The electrode receiving portion is adapted to be force-fitted over the end portion of the electrode and relies upon the resilience of the metal from which the terminal connector is formed to maintain electrical contact with the electrode. Often, after repeated emplacement and removal of the terminal connector, the electrode receiving portion becomes deformed as a result of exceeding the resilient limit of the metal from which the terminal connector is made and/or fatigue of the metal. When the electrode receiving portion of the terminal connector does not fit tightly on the electrode of the spark plug, the electrical connection is unreliable resulting in faulty operation of the internal combustion engine.

In certain applications, the interconnecting web of the terminal connector is bent to dispose the cable clamping portion at a predetermined angle to the electrode receiving portion. Oftentimes, during maintenance, the angular relationship between these two portions is inadvertently changed necessitating the rebending of the web in order to return the two portions to their proper angular relationship. After a few such bendings the interconnecting web breaks, thus rendering the terminal connector unfit for further use.

It is an object of this invention to provide an improved terminal connector.

Another object of the present invention is the provision of a terminal connector which has a relatively long service life.

Other objects and advantages of the invention will become apparent on reference to the following detailed description and drawings of which:

FIG. 1 is a plan view of a blank which may be formed into a terminal connector in accordance with the present invention;

FIG. 2 is a perspective view of the terminal connector formed from the blank of FIG. 1 shown clamped to the end of an ignition cable;

FIG. 3 is an end view of an alternate embodiment of a terminal connector formed from a blank similar to that shown in FIG. 1;

FIG. 4 is a plan view of a blank from which an alternative embodiment of a terminal connector may be formed in accordance with the present invention;

FIG. 5 is a perspective view of the terminal connector formed from the blank of FIG. 4, shown clamped to the end of an ignition cable; and

FIG. 6 is a cross-sectional view of the terminal connector of FIG. 5, taken along lines 6--6.

Very generally, the present invention provides a coupling, hereinafter referred to as a terminal connector, which may be formed from a metal blank 11 and includes an electrode receiving portion 13 and a cable clamping portion 15. The electrode receiving portion is an overlapping split sleeve which is formed by curling two walls 17 nd 19 so that a portion of one, 17 overlaps the other 19. Within the overlapping portion of the wall 17, there is located a generally rectangular slot 21. Extending outwardly from the overlapped portion of wall 19 are two generally rectangular, circumferentially aligned, spaced apart tabs 23 which are received in the rectangular slot 21. The tabs 23 cooperate with the slot 21 and limit expansion and contraction movement of the overlapping sleeve walls relative to each other.

The cable clamping portion 15 includes two wings 25 which are curled and clamped about the end of an ignition cable 80 to mechanically connect the cable to the terminal connector.

Generally, an ignition cable 80 is circular in cross section and is comprised of an electrically conductive core surrounded by a layer of electrically resistant material, which is the insulation, which in turn is surrounded by a layer of jacketing material. The electrically conductive core may be any suitable material such as copper wire or a carbonaceous filament. One method of electrically connecting the core to the terminal connector is by exposing a portion of the core and doubling it back along the exterior surface of the cable; when the wings 25 are clamped to the cable end the electrical connection is completed. Another method of electrically connecting the core to the terminal connector is by driving one leg of a U-shaped staple into a carbonaceous core, the other staple leg being disposed along the exterior surface of the cable. Again, when the wing walls are curled to mechanically connect the cable to the terminal connector, the electrical connection is completed.

Referring more particularly to the drawings, the blank 11 is used to form the terminal connector of FIGS. 2 and 3. This blank 11, as the other blank described hereinafter, may be stamped from any semirigid electrically conductive material having limited resilient characteristics, such as copper or brass-clad steel. The material is usually a metal having pliant qualities which allow the blank to be shaped into the desired configuration.

The blank 11 has the generally rectangular electrode receiving portion 13 interconnected by a web 31 to the generally rectangular cable clamping portion 15. The electrode receiving portion includes the walls 17 and 19 which terminate in edges 27 and 29 respectively. As mentioned previously, these walls are curled to form the split sleeve with the edge portions of the walls 17 and 19 overlapping. The wall 17 is provided an elongated rectangular slot 21 located a predetermined distance from the edge 27. The slot's two parallel minor sides 31 are disposed parallel to the edges 27 and 29 and thus are aligned normal to the circumference of the sleeve when the walls are curled.

The wall 19 is provided with a T-shaped cut 37 adjacent the edge 29 with the end of the leg opposite the cap of the T terminating at the edge 29, thereby affording two tabs 23. The cut 37 provides each of the tabs 23 with three distinct edges, a tab edge 39 which is aligned perpendicular to edge 29 and two parallel tab edges 41 which are aligned perpendicular to, and on either side of tab edge 39. Each of the tab edges 39 is of a predetermined lineal length which is approximately one-half the length of the major sides 43 of the slot. The length of a tab edge 41 is less than one-half of the length of the slot's minor sides 31. When upstruck, the tabs 23 each have a generally rectangular configuration with tab edge 39 being uppermost and the two tab edges 41 being upstanding.

Further provided in the electrode receiving portion is a detent 45 in the form of an indentation. This detent is positioned to engage the groove of a spark plug electrode when the terminal connector is emplaced thereon. In the illustrated embodiment the detent 45 is circular in plan, having its center strategically located on or near an imaginary line (not shown) which extends through the leg of the T-shaped cut 37 to the longitudinal center line of the slot 21.

The cable clamping portion 15 includes two wings 25 adapted to be clamped about a cable 80, almost totally circumscribing the cable. The wings 25 are provided with a plurality of semicircular cuts 47 which are struck out to form barbs that penetrate the cable when the wings 25 of the cable clamping portion 15 are curled and clamped to a cable.

Referring to a fully formed embodiment of the subject terminal connector, the upstruck tabs 23 have their uppermost tab edges 39 in circumferential alignment with the curled electrode receiving portion 13 and the tabs are within the slot 21. The tabs 23 are smaller than the slot 21 to permit limited relative movement between the overlapped and overlapping wall edges 27 and 29. The amount of this movement is limited by the upstanding tab edges 41 coming into contact with the rectangular slot sides 31. In this manner the tabs cooperate with the slot to insure the elastic limit of the metal forming the electrode receiving portion will not be exceeded by excessive spreading of the wall edges 27 and 29. There is no force acting upon the tabs which is capable of bending the upstruck tabs flat for, when a tab edge 41 strikes one of the slot edges 31, a shearing force is the primary force exerted against the tabs.

The slot 21 is formed within the wall 17 to provide the maximum width of material surrounding the slot. This construction provides a slot which is highly resistant to deformation.

The walls 17 and 19 are formed to overlap so as to provide a double thickness of material at the area of joinder of the split sleeve. This double thickness of material provides added strength to the sleeve thereby increasing the resistance to outward radial deformation of the walls 17 and 19 at the area of joinder.

Shown in FIG. 2 is an embodiment of a terminal connector formed from the blank 11 with its cable clamping portion 15 clamped to the free end of a cable 80. This terminal connector has its cable clamping portion 15 bent at an angle of approximately 135.degree. to its electrode receiving portion 13. This configuration is achieved by curling the walls of the electrode receiving portion and the wings of the cable clamping portion in the same angular direction and bending the web 31 to the extent necessary to place the cable clamping portion in the desired angular relationship to the electrode receiving portion. The walls 17 and 19 have been curled so as to cause the edge 27 to overlap the edge 29 with the upstruck tabs 23 being received in the rectangular slot 21.

Shown in FIG. 3 is an alternative embodiment of a terminal connector formed in accordance with the present invention. Parts similar to those shown in FIG. 2 are identified by its same reference numeral with the subscript a. The electrode receiving portion 13 a is formed as previously described, but the cable clamping portion 15a has its wings 25a curled in an angular direction opposite to that of the electrode receiving portion's walls 17a and 19a. This causes the wings of the cable clamping portion to be on the opposite side of the web 31a relative to the walls of the electrode receiving portion. The web is provided with notches 49 which facilitate the web's being bent to place the cable clamping portion at an angle of approximately 90.degree. to the electrode receiving portion. The notches 49 extend towards the center of the web to provide the web with a width, transverse to the longitudinal axis of the electrode receiving portion, which is less than the diameter of the sleeve defined by the curled walls 17a and 19a. In one embodiment of the subject terminal connector the width of the web is about 75 percent of the diameter of the sleeve.

Shown in FIG. 4 is a blank 11b which may be utilized to form an alternative embodiment of a terminal connector in accordance with the present invention. Parts similar to those of FIG. 2 are identified by its same reference numeral with the subscript b. The web 31b is increased in length so as to locate the cable clamping portion 15b a greater distance from the electrode receiving portion 13b and along its longitudinal edges is provided with two semi-circular notches 53 which facilitate the web being bent as will be hereinafter described. The cable clamping portion 15b comprises two wings 25b and is provided with two generally rectangular shaped corrugations each having a triangular tab 61. The triangular tabs 61 are bent inward to penetrate and firmly grasp the cable when the wings 25b are curled and clamped to a cable.

The electrode receiving portion 13b is formed as previously described, but is additionally provided with elongated trailing struts 65 which extend along and are spaced apart from either side of the web 31b. These struts 65 extend from the walls of the electrode receiving portion 13b towards the cable clamping portion 15b to have their free ends disposed adjacent the cable clamping portion. Within the free end of each of the struts 65, there is provided a V-shaped cut defining a barb 67 that may be struck outward from the strut 65.

The electrode receiving portion 13b may be formed as before and referring to FIG. 5, the web 31b may be bent to allow the cable clamping portion 15b to be at an angle to the electrode receiving portion 13b. In this angular alignment, the free ends of the struts 65 are in contact with the surface of a cable 80 and are located interiorly of the wings 25b which are curled about the cable 80 as previously described. The wings 25b of the cable clamping portion 15b are clamped to the cable 80 and the barbs 67 of the struts 65 are firmly embedded in the insulation of the cable 80.

Referring to FIG. 6, an embodiment of the subject terminal connector is shown in cross-section with one of the wings 25b of the cable clamping portion 15b overlying a strut 65. The strut 65 extends to be adjacent the cable 80 and is rigidly clamped to the cable by the wing 25b. The wing 25b is firmly clamped to the cable 80 causing the barb 67 to be embedded in the insulative material of the cable. By this arrangement a structure resembling a triangle is formed by the electrode receiving portion, the cable clamping portion, and the struts. As the strut 65 is generally a straight line connecting a point on the cable and the electrode receiving portion, any force which attempts to bend the web straight must either stretch the metal strut or pull the barb loose from its clamped, embedded position in the cable, thus making the web of the terminal connector very resistant to being bent straight. If the subject terminal connector is not to be used in a bent configuration, then the struts 65 are not needed and may be cut from the electrode portion by use of wire cutters or a similar tool or simply left in place since they will not obstruct or interfere with the operating function of the terminal.

While various embodiments of the invention have been shown and described, it should be apparent that various modifications may be made therein without departing from the scope of the invention.

Various of the features of the invention are set forth in the following claims.

Claims

What is claimed is:

1. A coupling for connecting an electrical cable mechanically and electrically to the electrode of a spark plug of an internal combustion engine, said coupling comprising, a first portion adapted to at least partially circumscribe and be firmly clasped to an electrical cable, mechanically fixing the cable in an electrically conductive relationship to said coupling; and a second portion adapted to circumscribe the end portion of an electrode, removably fixing the electrode end in an electrically conductive and mechanically connected relationship to said coupling, said second portion being formed of a resilient metal curled to form a sleeve having partially overlapping first and second walls, said first wall partially overlapping and being adjacent to said second wall, said first wall being provided with a slot located a predetermined distance from the overlapping wall edge, said slot having two parallel sides aligned normal to the circumference of said second portion, said second wall having a pair of tabs struck upwardly therefrom in generally normal relation to said second wall about bend lines disposed parallel to the circumference of said sleeve, said tabs being located interiorly of and adjacent the overlapped wall edge of said first wall, each of said tabs being adapted to project upwardly through said slot and having two upstanding tab edges which are located interiorly of said two parallel sides so that forces tending to circumferentially expand said sleeve act in a direction generally parallel to the bend lines defined at the intersections of said tabs with said second wall, and said tabs cooperating with said slot to limit the amount of relative movement between the overlapping and overlapped wall edges.

2. A coupling for connecting an electrical cable mechanically and electrically to the end portion of a spark plug electrode of an internal combustion engine, said coupling comprising, a first portion adapted to at least partially circumscribe and be firmly clamped to an electrical cable, rigidly fixing the cable in an electrically conductive and mechanically connected relationship to said coupling, said first portion having a wing adapted to be firmly clamped to the electrical cable, a second portion interconnected by a web to said first portion, said second portion being adapted to circumscribe the end portion of a spark plug electrode removably fixing the spark plug in an electrically conductive and mechanically connected relationship to said coupling, said second portion having at least one strut extending toward said first portion, said strut having a longitudinal length sufficient to cause an outer end thereof to underlie said wing and be firmly engaged against an electrical cable when said wing is clamped thereon, said strut having means thereon adapted to be embedded in said cable when said wing is clamped thereon.

3. The coupling of claim 2, wherein said second portion is comprised of a split sleeve having partially overlapping first and second walls and means are provided to limit relative movement between the overlapping wall edge and the overlapped wall edge.

4. The coupling of claim 2, including an electrical cable having a free end wherein said web is bent to position said first portion in a predetermined angular relationship with said second portion, and said wing is clamped to said cable free end with said strut being interposed between said cable and said wing.

5. A coupling as defined in claim 2 wherein said cable has an insulation sheath thereon, and wherein said means on said strut adapted to be embedded in said cable comprises at least one pointed barb adapted to penetrate said insulation sheath on said cable when said wing is clamped thereon with said outer end of said strut interposed between said wing and said insulation sheath.

6. A coupling as defined in claim 2 wherein said second portion has two struts extending toward said wing in parallel relation, said struts being adapted to underlie said wing and be firmly pressed against said cable when said first portion is bent at said web at a predetermined angle relative to said second portion of said coupling.