US3425029A

US3425029A - Electrical terminal

Info

Publication number: US3425029A
Application number: US662979A
Authority: US
Inventors: Alfred M Zak
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-08-24
Filing date: 1967-08-24
Publication date: 1969-01-28
Anticipated expiration: 1986-01-28

Description

Jam 28, 1969 A. M. ZAK 3,425,029

ELECTRICAL TERMINAL Filed Aug. 24/ 1967 Sheet of 2 ul 1 we 7 1 VENTOR.

ALFRED ZAK ATTORNEYS Jan. 28, 1969 A. M. ZAK 3,425,029

ELECTRI CAL TERMINAL Filed Aug. 24, 1967 Sheet 3 Of 2 4 so 66 4? 49 e2 e I 40 6o 4 1 VENTOR.

ALFRED ZAK ATTORNEY6 United States Patent 3,425,029 ELECTRICAL TERMINAL Alfred M. Zak, 6110 Casmere Ave., Detroit, Mich. 48212 Filed Aug. 24, 1967, Ser. No. 662,979 US. Cl. 339252 Int. Cl. H01r 11/22, /10, 9/08 18 Claims ABSTRACT OF THE DISCLOSURE In many industrial fields, for example, automotive, aircraft and appliance, the use of a great number of disconnectible electrical conductors have become very prevalent. Usually the disconnect feature is in the form of a pair of terminal blocks in which a plurality of male and female terminals are arranged so that they can be telescopically engaged and disengaged. Because of spacelimitations in many instances the sizes of such terminals have, by necessity, become progressively smaller and the problems encountered have become progressively greater. As the size (the diameter) of the terminal is reduced the sheet metal from which the terminal is fabricated is likewise reduced in thickness and with extremely thin sheet metal certain portions of the terminals become quite flimsy. Even with such small diameter terminals there remains the necessity of providing a terminal construction which insures good contact between the telescoping terminals and which at the same time enables the terminals to be solidly anchored within a terminal block so that they will not collapse or distort upon connecting or separating the terminal blocks.

It is also important in terminal blocks of the type describedthat the terminals be relatively firmly seated in the terminal blocks so that they are not apt to tilt and thus result in misalignment with the mating terminal when the terminal blocks are attempted to be connected.

Accordingly it is an object of the present invention to provide a terminal of the type described which is adapted to be of relatively rigid construction and which is further adapted to be firmly mounted Within a terminal block. A further object of the invention resides in the provision of a terminal which is so designed as to reduce to a minimum the problem of misalignment of mating terminals when terminal blocks are engaged with one another.

A further object of the invention is to provide a terminal designed so that it can be economically produced in progressive dies and, after forming a plurality of such terminals, connected to a carrier strip can be easily handled and fed to and from a reel.

A still further object of the invention resides in the provision of a terminal which is designed to assure good electrical contact with a mating terminal and to hold tightly when telescopically engaged.

In the drawings:

FIGURE 1 is a fragmentary view of a terminal block having a terminal of the present invention mounted therein;

FIGURE 2 is a plan view of the terminal shown in FIG. 1;

FIGURE 3 is a sectional view along the line 3-3 in FIG. 1;

Patented Jan. 28, 1969 FIGURE 4 is an end view of the terminal at its leading or front end;

FIGURE 5 is a sectional view taken along the line 5-5 in FIG. 3;

FIGURE 6 is a sectional view taken along the line 66 in FIG. 3

FIGURE 7 is a sectional view taken along the line 7-7 in FIG. 3;

FIGURE 8 is a sectional view taken along the line 88 in FIG. 3;

FIGURE 9 is a plan view of the sheet metal blank from which the terminal is formed prior to bending;

FIGURE 10 is a perspective view of the blank shown in FIG. 9 partially formed into the terminal;

FIGURE 11 is a sectional view illustrating the step of forming the blank illustrated in FIG. 10 into U-shapeg FIGURE 12 is a sectional view showing the body of the terminal formed into circular cylindrical shape;

FIGURE 13 is a sectional view of the terminal completely formed;

FIGURE 14 is a fragmentary perspective view of a modified form of terminal according to the present invention;

FIGURE 15 is a sectional view along the line 15-15 in FIG. 14.

In FIG. 1 a pair of terminal blocks 10 and 12 are illustrated. Within terminal block 10 there is arranged a male terminal 14 and within terminal block 12 there is arranged a female terminal 16.

Terminals

14 and 16 are of generally the same construction except for structural differences resulting from the fact that terminal 14 is a male terminal and terminal 16 is a female terminal. Accordingly, only the male terminal will be described in detail.

As is illustrated in FIGS. 2 and 3, terminal 14 is of generally cylindrical shape and is adapted to be formed from a flat sheet metal blank 18 (FIG. 9). At its front end terminal 14 is formed with a tapered nose 20 and adjacent its rear end the terminal is formed with

tabs

22 and 24 for crimping around a conductor 26. Tabs 22 are adapted to be crimped around the bared strands of conductor 26 whereas tabs 24 .are adapted to be crimped around the insulating coating of conductor 26. Between the nose 20 and the wire crimping tabs 22 the terminal is formed with a generally cylindrically shaped hollow body 28. The hollow body 28 of male terminal 14 is dimensioned so that its outer diameter has a slight interference fit with the inner diameter of the terminal 16.

Terminal block 10 is formed with a cylindrical bore 30 dimensioned to receive the cylindrical body 28- of terminal 14 with a close fit. Body 28 is formed with a counterbore 32 which connects with one end of bore 30 by a conical seat 34. A second counterbore 36 connects with bore 30 by means of a square shoulder 38.

Terminal body 28 is formed with a flexible tab 40 for interlocking engagement with shoulder 38 on terminal block 10. The manner in which tab 40 is formed is best illustrated in FIG. 9 wherein the blank from which the terminal is fabricated is shown. Blank 18 is connected at one end to a carrier strip 42. Carrier strip 42 is utilized for feeding successive blanks through the successive stations of a progressive die. Carrier strip 42 is also utilized for winding a strip of finished terminals into the form of a reel from which they are later adapted to be dispensed when the terminal is crimped on the end of a conductor. Blank 18 as shown in FIG. 9 is substantially fiat and is fashioned with opposed lugs 44 which provide the tabs 22 in the finished terminal and with a second set of opposed lugs 46 which form the tabs 24 in the finished terminal. The nose portion 20 of the terminal is defined in the blank by arcuately shaped, laterally spaced projections 48 the outer edges 49 of which merge with the 3

straight side edges

50, 52 of the blank. The inner arcuate edges 53 of projections 48 are spaced apart as indicated at 54 and terminate along the line 56 which is defined by a lance in the blank. Lance line 56 extends laterally to points aligned longitudinally with the apices 57 of projections 48. The space 54 is provided only as a matter of convenience in the design of the blanking punch and die.

In the form of terminal illustrated in FIGS. 1 through 3 tab 40 is formed along the edge 50 of blank 18 by a longitudinal lance 58 and a short transverse lance 60. Tab 40 is connected with blank 18 along the line 62. Tab 40 is bent to its final shape while blank 18 is in the substantially flat condition shown in FIG. 9. Tab 40 is formed into its final shape by bending the tab inwardly along the line 62 and then parallel to the plane of the blank along the line 64. The free end portion of the tab is bent perpendicular to the plane of the blank along the line 66. The side of the blank illustrated in FIG. 9 forms the inner surface of the terminal. Thus the portion 68 between bend lines 64 and 66 is raised when bent from the plane of the blank and the free end portion 78 of the tab is bent downwardly or outwardly at an angle of 90.

At the opposite side edge 52 of the blank there is formed a lug 72 which projects outwardly beyond the side edge 52 of the blank and which is defined by a pair of lances 74 extending inwardly from the side edge 52. While blank 18 is in the flat condition, a short clearance notch 76 is formed adjacent lug 72 and adjacent the free end portion 70 of tab 40 the lanced edge of the blank is coined as at 78 along the lance line 58. Notch 76 and coined edge 78 provide clearance indicated 80 in FIG. 7, to enable the free end portion 70 of tab 40 to move freely in a radial direction in the finished terminal.

While the blank is still in the flat, lug 72 is bent downwardly about the line 81 and is also bent into arcuate shape as shown in FIGS. 10, 11 and 12. Thereafter the opposite side edge portions of the blank, namely those portions extending laterally outwardly from the longitudinal center lines of projections 48, are curved upwardly as shown in FIG. to initiate forming the blank into hollow cylindrical shape. Simultaneously therewith the projections 48 are cupped into semicircular shape. The cupping of the inner opposed portions of projections 48 is facilitated by reason of the lance 56. The partially formed terminal shown in FIG. 10 is then subjected to a forming operation shown in FIG. 11 wherein the punch is designated 82 and the die 84. In this operation the central portion of the blank is subjected to a downward force so that in cross section the blank assumes a generally U-shape with inturned edges. It will be observed in this operation that the curved lug 72 clears the shank and nose of punch 82. by reason of the fact that it is initially bent along the line 80 out of the plane of the blank. Subsequent to the operation shown in solid lines in FIG. 11 the U-shaped blank is rolled into its final cylindrical shape by means of an upper die (not illustrated) that rolls or urges the

opposite edge portions

86, 88 into abutting relation. Such upper die would have clearance recesses for accommodating the projection 70 and the lug 72. At this stage in the fabrication of the terminal it would have a cross section as represented in FIG. 12 wherein it will be seen that the lug 72 extends radially outwardly beyond the cylindrical surface of the body portion of the terminal. In the final forming operation lug 72 is bent inwardly so that its free end 90 abuts against the lanced edge 58 on the body of the terminal as shown in FIG. 13. The sectional views illustrated in FIGS. 12 and 13 are taken generally at that portion of the terminal designated by the line 6-6 in FIG. 3.

With the above-described terminal construction the tab 40 is capable of flexing in the manner of a leaf spring so that when the terminal is inserted through bore 32 of the terminal block nose end first, the projecting portion 70 is engaged by the conical seat 34 and deflected inwardly so that the terminal can be inserted into the terminal block to the position shown in FIG. 1 where the tab fiexes radially outwardly and projection 70 engages behind shoulder 38. As is illustrated in FIGS. 1 and 3, the body of the terminal is formed with a radial protuberance 92 which is adapted to engage conical seat 34 and thereby limit axial movement of the terminal in the terminal block. When the terminal is subjected to an axial force, such as when it is being telescopically engaged with the female terminal 16, projection 70 engages shoulder 38 to prevent the terminal from being displaced rearwardly in the terminal block. Lug 72 forms a bridge which extends over the inwardly struck portion 68 of tab 40 directly in front of projection 70. Thus, lug or bridge 72 provides a backing support for projection 70 and limits the extent to which tab 40 flexes in an outward direction.

Since lug 72 extends circumferentially over the inwardly struck portion 68 of tab 40 it protects the tab from accidental displacement. Bridge 72 also provides the body of the terminal with a circumferentially continuous periphery at the portion of the terminal occupied by the tab.

The terminal construction described herein is also desirable from the standpoint that it has a minimum of cut-away portions in the body thereof. This is important not only from the standpoint of strength but also from the standpoint of providing a maximum cross sectional area which will minimize the millivolt drop due to resistance. It Will also be observed that the portion of the terminal body opposite tab 40 and engaged within the bore 30 of the terminal block is circumferentially continuous. Thus, there is little tendency for the terminal to tilt when the projection 70 is pressed against the shoulder 38 which would otherwise be the case if the portion of the terminal body opposite tab 40 were slotted or otherwise cut away. This is important from the standpoint of maintaining the terminal in accurately centered position within the terminal block. If the terminal has a tendency to tilt substantially and considering that as many as fifteen or twenty terminals might be mounted in the same terminal block, then the possibility of misalignment between the male and female terminals when it is attempted to interconnect the terminals is very great. In this connection the bullet nose shape of the leading end of the terminal is also important from the alignment standpoint. The nose portion of the terminal can be made solid to substantially the tip thereof by reason of the lance 56 which enables both projections 48 to be cupped into generally semicircular shape. Thus, the solid nose 20 provides a desirable lead in end on the terminal for minimizing the effect of slight misalignment between opposed male and female terminals.

The modified terminal construction shown in FIG. 14 is substantially the same as previously described except that the tab 94 is connected to the body of the terminal by a pair of

bend lines

96, 98 which extend longitudinally of the terminal body rather than transversely as is the case with bend lines 62, 64. The construction shown in FIGS. 14 and 15 is desirable in that the tab 94 is capable of flexing more freely than is the case of tab 40 wherein the connection between bend lines 62 and 64 has a transition from a curved to a flat surface. In other respects the terminal shown in FIGS. 14 and 15 is the same as the embodiment previously described.

I claim:

1. An electrical terminal of the type adapted to be inserted within a socket of a terminal block and having a hollow elongate body formed of resilient sheet material and having a forward end and a rear end, said forward end being adapted for telescopic connection with another terminal and said rear end having means thereon for connection with an electrical conductor, said body having a longitudinal seam along one side thereof defined by opposed edge portions of the sheet material from which the terminal is formed, one of said edge portions having a tab struck inwardly therefrom, said tab extending lengthwise of the terminal and having its forward end portion connected to the body and its rear end portion free, said tab being bent radially outwardly of the body at said rear end portion so that the free end of the tab projects radially outwardly beyond the outer surface of the body adjacent said seam, the opposite edge portion of the body having a lug thereon which extends circumferentially over the inwardly struck portion of the tab, said lug having a rear edge which is disposed forwardly of and closely adjacent the radially projecting free end portion of the tab.

2. A terminal as called for in claim 1 wherein the portion of the tab adjacent its connection with the body is substantially fiat to permit the tab to flex readily in a radial direction.

3. A terminal as called for in claim 1 wherein the portion of the tab between its connection with the body and said radially outwardly bent free end is disposed radially inwardly of the inner surface of said body.

4. A terminal as called for in claim 1 wherein the circumferentially extending lug has an axial extent substantially less than the axial extent of the inwardly struck portion of the tab.

5. A terminal as called for in claim 1 wherein said body is of generally cylindrical shape and cross section and said lug lies in the cylindrical surface of the body.

6. A terminal as called for in claim 1 wherein said tab is defined in part by a lanced edge on the body which extends longitudinally of the body, the free end of the lug abutting said lanced edge on the body.

7. A terminal as called for in claim 1 wherein said tab is defined in part by a lanced edge on the body which extends longitudinally of the body, the portion of said lanced edge and said opposite edge of the body adjacent the radially outwardly bent free end of the tab being shaped to provide clearance for the adjacent side edges of the tab to thereby permit the tab to fiex readily.

8. A terminal as called for in claim 1 wherein said lug is defined in part by a pair of axially spaced lanced edges which extend circumferentially in said body from said opposite edge portion.

9. A terminal as called for in claim 1 wherein the portion of said body diametrically opposite said tab is defined by a substantially continuous circumferentially extending surface.

10. A terminal as called for in claim 1 wherein said tab is connected to the body along a line extending transversely of the tab.

11. A terminal as called for in claim 1 wherein the tab is connected to the body along a line extending longitudinally of the tab adjacent the end thereof opposite said free end.

12. A terminal as called for in claim 1 wherein the tab is connected with the body of the terminal by a connecting portion defined by a pair of spaced-apart bend lines.

13. A terminal as called for in claim 1 wherein said body has a portion spaced rearwardly of said projecting portion of the tab which is circumferentially continuous.

14. The method of making an electrical terminal from sheet stock which comprises forming a flat blank with opposite straight side edge portions, lancing the blank along a line spaced inwardly from one of the side edges of the blank and along at least one other line extending transversely between the first lance line and said one side edge to define a tab on the blank, displacing said tab into a plane parallel to and above the plane of the blank, bending the free end portion of the tab adjacent the second lanced line downwardly at a substantially right angle to the plane of the tab, forming a laterally extending lug on the other side edge portion of the blank such that the lug is provided with a pair of opposite side edges which 7 extend generally perpendicularly to the last-mentioned edge portion of the blank, lancing the body of the blank along a pair of lines forming continuations of the side edges of the lug, bending said lug downwardly along a line extending between the inner ends of said last-mentioned lanced lines, curving the opposite side edge portions of the blank upwardly to initiate formation of the blank into a hollow body, pressing the central longitudinal portion of the blank downwardly to form the blank into generally U-shape with in-turned edges, bringing said in-turned edges together to form the blank into a hollow body having a seam defined by the abutting in-turned edges and thereafter bending said lug radially inwardly to a position wherein it overlies said tab and the free end thereof abuts said first-mentioned lanced edge of the blank.

15. The method called for in claim 14 wherein said lug is located on the blank such that when it is bent to said position overlying the tab it is closely adjacent the radially projecting free end portion of the tab.

16. A male electrical terminal formed from sheet material and adapted to telescopically engage with a female terminal, said male terminal having a hollow cylindrical body, said body having a longitudinal seam along one side thereof defined by the abutting edges of the sheet material from which the terminal is formed, said body having a tapered bullet-shaped nose at one end which merges with the cylindrically-shaped portion of the body, said seam extending longitudinally to the leading end of said nose, the junction between said nose and the cylind'rical portion of the body being defined at the portion thereof opposite said seam by a lanced line extending circumferentially around said junction through an arc of about 17. A terminal as called for in claim 16 wherein said lanced line is symmetrically disposed relative to said seam.

18. The method of forming a hollow male electrical terminal from sheet material which comprises forming a flat blank having a body portion, the body portion of the blank having opposite side edges and having adjacent one end thereof a pair of arcuately-pointed symmetrical projections of generally the same size and shape, each of said projections having an arcuate outer side edge which connects with a side edge of the body portion of the blank, said projections also having arcuate inner side edges which converge towards one another and towards the longitudinal center line of the body portion of the blank, said inner arcuate edges terminating at a line which is circumferentially aligned with said connection between said outer arcuate edges and the opposite edges of the body portion forming a lance through the blank along said last-mentioned line, said lanced line extending from between the inner ends of said inner arcuate edges laterally outwardly to points generally aligned longitudinally with the apices of said projections and thereafter bending said blank into hollow form of generally circular cross section so that the opposite side edges of the body and the arcuate side edges of the two projections are in generally abutting relation.

References Cited UNITED STATES PATENTS 2,980,883 4/1961 Scheller. 3,311,866 3/ 1967 Williamson. 3,325,775 6/ 1967 Zak. 3,275,973 9/ 1966 Shlesinger 339-2l7 FOREIGN PATENTS 436,173 l0/l935 Great Britain. 852,563 10/ 1960 Great Britain.

MARVIN A. CHAMPION, Primary Examiner.

PERRY TEITELBAUM, Assistant Examiner.

U.S. C1. X.R.