US 3546665 A
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Description (OCR text may contain errors)
Dec. 8., 1970 A. M. ZAK 3,546,665
IGNITION CABLE CONNECTOR Filed Feb. 24, 1969 4 Sheets-Sheet 1 FIG. I
l6 I5 40 49a. 0 3 5 A 5 3o MWW9-M ATTORNEYS Dec. 8, 1970' I A. M. ZAK 3,5 6,
' IGNITION CABLE CONNECTOR Filed Feb. 24, 1969 4 Sheets-Sheet 2 INVENTOR. ALFRED M. ZAK
ATTOQNEY5 Dec. 8, 1970 A. M. ZAK 3,546,665
7 IGNITION CABLE CONNECTOR Filed Feb. 24, 1969 4 Sheets-Sheet S k 92/9; I 4, 64 Q 86 4 1 2 I 4 /2 .L I n 90 v j L 88 FIG. l2
INVENTOR. ALFRED M. ZAK
ATTORNEYS Dec. 8., 1970 A. M. ZAK
IGNITION CABLE CONNECTOR 4 Sheets-Sheet 4.
Filed Feb. 24, 1969 INVENTOR. ALFRED M. ZAK
BY M K W M ATTORNEYS United States Patent 3,546,665 IGNITION CABLE CONNECTOR Alfred M. Zak, 6110 Casmerc Ave., Detroit, Mich. 48212 Filed Feb. 24, 1969, Ser. No. 801,657 Int. Cl. H01r 13/12 US. Cl. 339-256 19 Claims ABSTRACT OF THE DISCLOSURE A connector for releasably connecting an ignition cable to a terminal of a spark plug or distributor of an internal combustion engine. The terminal engaging end of the connector is formed as a tubular body with two axially adjacent sections having their longitudinal edge portions spirally overlapped in opposite directions.
This invention relates to a detachable connector for electrically connecting an ignition cable to the terminal of a spark plug or a distributor of an internal combustion engine.
It has been proposed heretofore to construct a spark plug connector from a fiat sheet metal blank formed into tubular shape with or without overlapping edge portions. The problem that frequently arises with a connector of this type is that, if it is removed from the terminal at the end of a spark plug by pulling the ignition cable at an angle inclined substantially from the axis of the spark plug, the tubular body portion of the connector has a tendency to expand and distort to an extent that the connector is unduly enlarged and distorted to an out-ofround shape so that it will not thereafter have the required retention fit with the terminal when the connector is again engaged with the spark plug.
The present invention has as its primary object the provision of a connector of the type described adapted to resist undue expansion and distortion when removed from the terminal of a spark plug or a distributor so that it will retain its dimensions and firmly grip the terminal after repeated removal and recoupling of the connector with the terminal.
A further object of the invention is to provide a connector of the type described having two separate and axially adjacent tubular sections which, to a slight degree, are adapted to circumferentially expand and contract independently of one another and each of which nevertheless exerts a restraining force tending to resist radial enlargement of the other.
A still further object of the invention is to provide a connector of the type described with edges which are overlapped in such a manner as to resist radial distortion and restrict enlargement of the tubular terminal engaging portion to a slight uniform circumferential expansion and contraction.
Another object of the invention is to provide a connector of the type described which on the one hand has relatively great strength and which on the other hand has ample resiliency so that it can be repeatedly engaged and disengaged with the terminal of a spark plug or a distributor without impairing its ability to firmly grip the terminal when engaged therewith.
In the drawings:
FIG. 1 is a fragmentary elevational view of an ignition cable with a connector of the present invention crimped thereon and engaged with the terminal of a spark plug.
FIG. 2 is a sectional view along the line 2-2 in FIG. 1.
FIG. 3 is a sectional view along the line 33 in FIG. 1.
FIG. 4 is a sectional view along the line 44 in FIG. 1.
FIG. 5 is a sectional view along the line 55 in FIG. 1.
3,546,665 Patented Dec. 8, 1970 FIG. 6 is a plan view of the flat blank from which the connector illustrated in FIG. 1 is formed.
FIGS. 7, 8, 9 and 10 show the successive forming op erations employed for forming the blank of FIG. 6 into the finished connector.
FIG. 11 is a view similar to FIG. 1 and showing a modified form of connector.
FIG. 12 is a sectional view along the line 1212 in FIG. 11.
FIG. 13 is a fragmentary elevational view of an ignition cable and distributor cap interconnected by the connector of the present invention.
FIG. 14 is a sectional view along the line 14-14 in FIG. 13.
FIG. 15 is a sectional view along the line 15-15 in FIG. 13.
FIG. 16 is a fragmentary longitudinal sectional view of a slightly modified form of connector for a distributor.
Referring to FIGS. 1 and 2, an ignition cable 10 is shown connected to a terminal 12 at the upper end of a spark plug 14 by the connector 15 of the present invention. While such terminals differ slightly in their construction, they generally comprise a tapered free end portion 16 which merges into a circular cylindrical portion 18 which then converges as at 20 to a neck portion 22 which connects with a circular cylindrical portion 22 which connects with a circular cylindrical portion 24. Generally the circular cylindrical portions 18 and 24 have the same diameter. With some spark plugs, however, the diameters of the cylindrical portions 18 and 24 may differ slightly by a few thousandths of an inch. Connector 15 is designed to frictionally engage with a firm grip the terminal 12 regardless of whether the two cylindrical portions 18 and 24 have the same diameter or have slightly different diameters.
Connector 15 is formed as a generally cylindrical body of tubular shape having one end 26 adapted to be crimped to an end of cable 10 and has its opposite end 28 shaped for frictional engagement with terminal 12. Terminal engaging end 28- is generally divided into two axially adjacent sections 30, 32. Each section is of generally circular cylindrical shape having spirally overlapping end portions. As shown in FIG. 4, section 32 has an underlying end portion forming a wing 34 and an overlying or overlapping portion forming a wing 36. Section 30, as shown in FIG. 5, has an underlying wing 38 and an overlying or overlapping wing 40. Referring to FIG. 1 and comparing FIG. 4 and FIG. 5, it can be seen that the overlapping wings 36, 40 extend circumferentially in opposite directions and the underlying wings 34, 38 likewise extend circumferentially in opposite directions.
FIG. 6 illustrates the blank utilized in forming a connector 15. The blank, which is generally designated 42, is formed from sheet metal such as cold rolled sheet steel or a nonferrous sheet metal such as brass, the thickness of which may vary considerably (for example, from .010" to .020", a thickness of about .015" being preferred). The end of the blank which forms the portion 26 of the connector is formed with a plurality of lanced lugs 44 which, when the blank is rolled into tubular shape, are adapted to be struck inwardly as shown in FIG. 3 to firmly crimp the connector with an end of ignition cable 10. The portion of the blank which forms the crimping end 26 of the connector is connected with the end 28 by a central portion 46 of reduced width. In the finished connector the central portion 46 forms the generally semicircular portion of the connector on the side thereof diametrically opposite the overlapping wings. At one side of terminal engaging end 28 of blank 42 the blank is formed with the wings 36, 38 and the opposite lateral side edge portion of end 28 of the blank is formed with wings 34, 40. The wings at each side of the blank are separated axially from one another by laterally inwardly extending notches 48. It will be observed that wings 36 and 40 extend laterally beyond the adjacent wings 38 and 34, respectively. Between the two wings 38, 40 the blank is provided with a shallow groove 50 which may be formed by coining, stamping or the like. Groove 50 has an axial dimension slightly greater than the width of cylindrical portion 18 of the spark plug terminal. Wings 34 and 38 are formed with rectangular apertures 49 and Wings 36 and 40 are formed with a lanced tab 51 of rectangular shape. After lancing tabs 51 are flattened back into the plane of the blank.
The connector of the present invention is designed to be formed progressively between successive die sections from a continuous strip of sheet metal and, accordingly, they are connected to carrier strips 52 by lugs 54. After forming, connectors 15 (still attached to carrier strips 52) are wound into coils. The connectors are adapted to be sheared from lugs 54 when they are eventually applied to the ends of ignition cables.
FIGS. 7 through 10 show the successive forming operations to which blank 42 is subjected in shaping the blank into the finished connector. The construction of the progressive die utilized for these forming operations is well known to those skilled in this art and need not be described. After the blank is formed in the flat to the configuration shown in FIG. 6 the opposite side edge portions of end 28 of the blank are turned upwardly slightly as shown in FIG. 7. More specifically, it will be observed that wings 34 and 38 are oflset inwardly or upwardly from the plane of wings 40 and 36 a distance corresponding generally to metal thickness. Thus, between the adjacent wings on each side of the blank there is a bent transition metal section 56 (FIG. 2) by means of which the two adjacent wings on each side of the blank are interconnected. In the showing of FIG. 7 these transition portions of the blank extend from the inner edges 58 of notches 48 inwardly to the portions of the blank indicated by the lines 60 in FIG. 7. In the finished connector lines 60 divide the connector horizontally at each side into upper and lower halves along a central diametral plane as indicated at 62 in FIGS. 4, and 10. Lines 60 are generally axially aligned with the edges of central portion 46 at the narrowest section thereof. Between the edges 58 and the points 64 on each side of the blank the transition portion 56 is of uniform inclination and the inclination thereafter gradually diminishes to zero between the points 64 and lines 60. In FIG. 1 the portions of the transition areas 56 of uniform inclination are designated 66 and the portions of diminishing inclination are designated 68.
The operation shown in FIG. 8 illustrates the manner in which the blank is initially formed into generally U shape and in the forming operation illustrated in FIG. 9 the upper free ends of the U at the end 28 of the blank are directed inwardly toward each other so that the extreme free edge portion of wing 36 overlies the extreme free edge portion of wing 34 and the extreme edge portion of wing 40 overlies the extreme free edge portion of wing 38. In the operation illustrated in FIG. 9 the side edge portions 70 at the end 26 of the connector are turned upwardly inwardly as shown. In the final forming operation illustrated in FIG. the terminal engaging end 28 of the connector is formed into its finished tubular shape wherein wing 36 completely overlies wing 34 and wing 40 completely overlies wing 38-. It will be appreciated that in the forming operations illustrated in FIGS. 8 through 10 suitable mandrels are employed for obtaining the desired internal configuration of the connector.
When the tubular portion of the terminal is completely formed as shown in FIG. 10 tab 51 registers with and overlies aperture 49. As is shown in FIG. 6, tab 51 has an axial dimension greater than aperture 49 and has a lateral dimension less than aperture 49. Tab 51 is then bent inwardly by an appropriately shaped punch into V shape as shown in FIG. 2 with the opposite edges of aperture 49 serving as fulcrum edges for the bending operation. Since tabs 51 have a width less than apertures 49 it follows that the side edges 51a of tabs 51 engage the side edges 49a of apertures 49 to limit the extent to which the terminal engaging end 28 of the connector is able to circumferentially expand.
As shown in FIGS. 4, 5 and 10, the extent of the overlapping and underlying wings preferably comprises an arc A of or more. In addition, it will be noted that with respect to section 32 of the connector (FIG. 4) the inner surface thereof is of substantially circular cylindrical shape through arc B which is preferably about 315; that is, from the line 60 at the right of FIG. 4 clockwise to the free end of wing 34. Likewise, as shown in FIG. 5, with respect to section 30 the inner surface of the connector is of circular cylindrical shape through an arc of about 315. It will be also noted that in the finished connector the overlapping and underlying wings are generally in contacting relation.
The connector constructed as disclosed herein has distinct advantages over spark plug connectors as conventionally formed. Since the two sets of overlapping and underlying wings extend circumferentially in opposite directions, each set of wings exerts a restraining force on the other set against a radial displacement of the wings which frequently occurs when spark plug connectors of conventional design are disengaged from a spark plug terminal by pulling on the ignition cable at an angle inclined substantially to the axis of the spark plug. With the connector of the present invention the overlapping and underlying wings restrict enlargement of the tubular terminal engaging end 28 of the connector to a uniform circumferential expansion within the limits permitted by the interengagement of locking tab 51 with the edge of aperture 49. When the connector of this invention is telescopically engaged with the terminal 12 of a spark plug, the two sets of overlapping and underlying wings slide circumferentially over one another. As the leading end of the connector slides over the tapered portion 16 of the terminal and when section 32 of the connector becomes seated on the cylindrical portion 24 of the terminal, groove 50 registers with the cylindrical portion 18 of the terminal so as to slightly contract and snap into frictional locking engagement with the terminal. When the connector is thus interengaged With the spark plug terminal as shown in FIG. 2, section 32 of the terminal tightly embraces the cylindrical portion 24 and section 30 tightly embraces the cylindrical portion 18 of the terminal. This occurs regardless of whether the cylindrical portions 18 and 24 of the terminal are of the same diameter or differ in diameter by a few thousandths of an inch because, at least to a slight extent, the two sections 30, 32 of the connector are adapted to circumferentially expand and contract independently of one another. For example, when a connector of the type disclosed herein having in its free state a diameter of .310" at section 30 and .311 at section 32 was telescopically engaged with a terminal 12 as shown in FIG. 2 wherein both sections 18 and 24- had a diameter of .250, the two sections of the connector expanded slightly different amounts. In the engaged condition of the connector section 30 expanded to an outer diameter of .311" and section 32 expanded to an outer diameter of .315". When the connector was removed from the terminal the two sections of the connector contracted to their original diameters as given above for the free state. The connector referred to was formed of 1020 cold rolled steel having a nominal thickness of .020". The independent expansion and contrac tion of the two sections 30, 32 of the connector is determined to a large extent by the length of slots 48. If the slots are increased in length the independent action of the two sections is increased.
It will be appreciated. however. that in view of the construction of the connector disclosed the extent to which the two sections 30, 32 are capable of circumferentially expanding and contracting independently of one another is significant but very limited. This results in part from the fact that the transition portion 56 between the axially adjacent wings on the two sections is bent both axially and circumferentially of the connector so as to impart substantial rigidity to the connector as a whole. As a matter of fact, the rigidity imparted to the connector by reason of these transition sections enables the connector of this invention to be formed from sheet metal such as 1020 cold rolled sheet steel having a thickness of .015" as distinguished from conventional spark plug connectors which are normally formed from .020" sheet steel.
The transition sections 56 between the two sections 30, 32 of the connector have a secondary advantage as well. When the terminal is being removed these transition portions exert a locking effect when they encounter the narrow cylindrical section 18 of the terminal which requires the exertion of an additional axial force to pass over the cylindrical section 18.
Another advantage of the connector of this invention is that it can be easily formed in a progressive die. For example, it will be noted that, since the overlapping and underlying wings extend circumferentially in opposite directions on the two sections 30, 32 of the connector, :1 very substantial extent of overlap can be obtained without exerting undue torque on the blank which would tend to distort. Referring specifically to FIGS. 9 and 10, the torque in one direction resulting from the forming of wing 36 over wing 34 is balanced by the torque in the opposite direction resulting from the forming of wing 40 over wing 38. Thus a very substantial amount of overlap can be obtained without creating problems in the forming operation. A substantial overlap is, of course, desirable since it enhances the locking effect of the connector on the terminal and also resists radial displacement of the two sets of wings.
It will be appreciated that, although two oppositely disposed locking tabs 51 are shown, if desired, a single locking tab could be formed on Wing 36 to interengage with the edge of the underlying aperture on wing 34. The provision of one or more locking tabs of the type shown is very desirable. Since the locking tabs are completely surrounded by metal they are protected and do not form protrusions at the edges of the terminal which might catch and tangle with other connectors during reeling and unreeling operations. The V shape of the locking tab imparts substantial strength to it and enables the tab to be readily formed. In addition, since the punch utilized for forming the locking tab will also be of V shape, the punch itself is not fragile.
Referring now to FIGS. 11 and 12, connector 70 shown therein differs from the previous spark plug connector described primarily in only one respect. The terminal engaging end 72 of connector 70 is divided into three axially adjacent sections 74, 76 and 78. Section 74 has an overlapping wing 80 and an underlying wing 82. Section 76 has an overlapping wing 84 and an underlying wing 86. Section 78 has an overlapping wing 88 and an underlying wing 90. The overlapping and underlying wings of section 74 extend circumferentially in the same direction as the overlapping and underlying wings of section 78. However, the overlapping and underlying wings of section 76 extend in the opposite direction from the wings on sections 74 and 78. Wings 80 and 88 are formed with inwardly bent tabs 92 adapted to engage with the circumferentially spaced edges of underlying openings 94 in wings 82 and 90 to limit the circumferential expansion and contraction of the terminal engaging end of the connector. As shown in FIG. 12, wings 84 and 86 of section 76 are located so as to register with the radially ensmalled portion of spark plug terminal 12 which lies between the cylindrical portions 18 and 24.
The connector show in FIGS. 11 and 12 is merely lanced between successive wings rather than forming transition areas as shown at 56 in FIG. 2. Accordingly, the wings on connector 70 are more readily flexible than the wings on connector 15 but the connector as a whole operates generally the same as previously described since there are three sets of wings on connector 70 as compared with two sets of wings on connector 15.
The connector 96 shown in FIGS. 13 through 15 is adapted for interconnecting an ignition cable 10 with a socket terminal 98 within the upper end of a distributor cap 100. Connector 96 is shaped and formed substantially the same as connector 15 except that the locking tab 51 and aperture 49 are omitted and also the overlapping wing 40a is fashioned with a circumferentially extending slot 102. Terminal 98 is formed as a generally circular cylindrical cup-shaped receptacle having an outwardly flared entrance lip 104 which intersects with a radial enlargement 106 to form an annular inwardly extending shoulder 108. The inner diameter of terminal 98, and specifically the shoulder 108, is less than the outer diameter of connector 96 so that when the connector is telescopically inserted into terminal 98 it is contracted slightly and snaps into engagement with the terminal when slot 102 registers with annular shoulder 108 and the portion 110 of wing 40 registers with the groove formed by enlargement 106. This is facilitated by the fact that the lower portion 112 of the terminal has an inner diameter which is slightly greater (.001 to .002" less than the inner diameter of the terminal at annular shoulder 108). Portion 110 of wing 40 has an axial dimension slightly less than the groove formed by enlargement 106.
The terminal shown in FIG. 16 is generally the same as that shown in FIG. 13 except that the slot 102 in wing 40a is omitted and in place thereof the opposite side wall portion of the connector is formed with one or more protuberances 114 which are adapted to interengage with the groove formed by radial enlargement 106 on terminal 98 when the connector is telescopically engaged with terminal 98.
1. A connector for use at the end of an ignition cable for releasably connecting the cable to a terminal on a spark plug or distributor of an internal combustion engine, said connector having one end adapted for connection with said cable and having a tubular body at its opposite end adapted for telescopic engagement with said terminal, said body comprising two integrally connected, axially adjacent sections each having longitudinally extending and circumferentially overlapping edge portions, said overlapping edge portions defining on each section an outer underlying wing and an inner underlying wing, the outer wings on the two sections extending circumferen- :tially in opposite directions and the two inner wings extending circumferentially in opposite directions, said body being adapted to be telescopically engaged with said terminal.
I 2. A connector as called for in claim 1 wherein the inner and outer wings of the two sections overlap through a circumferential extent of at least 60.
3. A connector as called for in claim 1 wherein the inner and outer wings of the two sections overlap through a circumferential extent of at least 4. A connector as called for in claim 1 including means on at least one of said sections forming a radially extending abutment adapted to interengage with a circumferentially extending radial abutment on the terminal to retain the connector on the terminal in a releasably interengaged condition when the connector is telescopically engaged with the terminal.
5. A connector as called for in claim 1 wherein each outer wing extends circumferentially beyond the free end of the axially adjacent inner wing.
6. A connector as called for in claim 1 wherein the axially adjacent circumferentially extending edges of the two outer wings are spaced apart axially to provide a circumferentially extending clearance space therebetween.
7. A connector as called for in claim 4 wherein at least a portion of the circumferentially extending adjacent edges of the outer Wing of one section and the inner Wing of the other section are integrally connected.
8. A connector as called for in claim 6 wherein the circumferentially extending adjacent edges of the outer wing of one section and the inner wing of the other section are integrally connected by a circumferentially extending portion which inclines radially outwardly from said inner wing to said outer wing.
9. A connector as called for in claim 6 wherein a circumferentially extending portion of the axially adjacent edges of each outer Wing is connected to the inner wing of the adjacent section by a radially bent portion.
10. A connector as called for in claim 1 including means on the section more remote from said opposite end of the connector forming a radial abutment thereon adapted to interengage with a circumferentially extending radial abutment on the terminal to retain the connector on the terminal in a releasably interengaged condition when the connector is telescopically engaged with the terminal.
11. A connector as called for in claim 10 wherein said wings are slidably engaged for relative circumferential movement and said abutment means comprises a circumferentially extending groove around the inner periphery of said more remote section.
12. A connector as called for in claim 10 wherein said last-mentioned abutment means comprises a radially outwardly extending protuberance.
13. A connector as called for in claim 1 wherein said sections are adapted to circumferentially expand and contract and including interengaging abutment means on at least the inner and outer wings of one section for limiting the extent of circumferential expansion of the connector.
14. A connector as called for in claim 13 wherein said interengaging abutment means comprises an opening lying completely within the periphery of the last-mentioned inner wing, said opening having a pair of cirrumferentially spaced edges and an inwardly bent tab on the lastmentioned outer wing disposed within said opening and having a circumferential extent less than the spacing between said pair of edegs of the opening in the inner wing.
15. A connector as called for in claim 14 wherein said tab is connected with said one outer wing by a circumferentially extending bend line which registers with a circumferentially extending edge of the underlying opening.
16. A connector as called for in claim 14 wherein said opening has a pair of circumferentially extending axially spaced edges, said tab being V shaped with its legs contacting said last-mentioned edges of the opening.
17. The method of forming a connector for use at the end of an ignition cable for releasably connecting the cable to a terminal on a spark plug or distributor of an internal combustion engine which comprises forming a blank having opposite side edge portions; dividing each side edge portion into a pair of adjacent wings, the two Wings on one side edge portion being transversely aligned with the two wings on the other side edge portion; offsetting one wing on each side of the blank from the plane of the other wing a distance corresponding generally to the thickness of the blank, the offset wing being diagonally aligned on the two side edge portions of the blank; and then forming the blank into tubular shape with one wing on each side edge portion overlapping a wing on the other side edge portion.
18. The method called for in claim 17 wherein the blank is initially formed with each overlapping wing projecting laterally outwardly beyond the other wing on the side edge portions of the blank.
19. The method called for in claim 17 wherein the adjacent side edges on the wings at each side edge portion of the blank are spaced apart and the portion of the blank between said adjacent side edges of the wings is bent to form a radially extending shoulder connecting and extending between the offset wing and the other wing on each side edge portion of the blank.
References Cited UNITED STATES PATENTS MARVIN A. CHAMPION, Primary Examiner J. H. MCGLYNN, Assistant Examiner US. Cl. X.R. 29630; 113--119 233 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Dat d December 8, 1970 Patent No. 3,546,665
Inventor(e) K, Alfred M.
It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Column 7 Line 3 Cancel "4" and insert 6 Column 8 -Line 17 Cancel "wing" and insert wings smnm sm UB9 1921 Acme van-mu 1:. saamm, JR M l cmmm or Patents! Meeting Office!