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Publication numberUS3650025 A
Publication typeGrant
Publication dateMar 21, 1972
Filing dateOct 31, 1969
Priority dateOct 31, 1969
Publication numberUS 3650025 A, US 3650025A, US-A-3650025, US3650025 A, US3650025A
InventorsColvis Arthur Louis, Mclaughlin Bernard John
Original AssigneeItt
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Process of forming electrical connectors
US 3650025 A
Electrical connector or terminal lugs are provided by using bending, stretching and drawing techniques rather than cold flow methods. To fabricate the terminal lugs, a flat piece of aluminum or copper is first formed as a cup by drawing techniques. Then, the closed end of the cup is sheared free, flattened and wedged within the walls of the cup. Afterward, suitable holes are punched or drilled to accept wires, or cables, and fasteners. The resulting terminal lugs may be used in fastening wires or cable to bus bars.
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Description  (OCR text may contain errors)

United States Patent McLaughlin et al.

[451 Mar. 21, 1972 PROCESS OF FORMING ELECTRICAL CONNECTORS Inventors: Bernard John McLaughlin, St. Louis; Arthur Louis Colvis, Hazelwood, both of Mo.

International Telephone and Telegraph Corporation, New York, N.Y.

Filed: Oct. 31, 1969 Appl. No.: 872,918


US. Cl. ..29/629, 29/630 R, 113/119, 339/272 R, 339/263 R,.339/277 R Int. Cl. ..H02g 15/00, HOlr 9/00 Field ofSearch ..29/630R; 1 13/1 19; 339/272, 339/263, 277

References Cited UNITED STATES PATENTS 1/1911 Hector .;.'.'.'.;...339/2'"7 2 2,185,981 1/1940 l-luller ..29/630X 2,223,853 12/1940 Mebold ..29/630 Primary Examiner-John F. Campbell Assistant ExaminerRobert W. Church Attorney-C. Cornell Remsen, Jr., Walter J. Baum, Percy P. Lantzy, J. Warren Whitesell, Delbert P. Warner and James B. Raden [57] ABSTRACT 6 Claims, 23 Drawing Figures PATENTEDMARZI I972 3.650.025

sum 2 or 4 FIG. .9

FIG. /0


PROCESS OF FORMING ELECTRICAL CONNECTORS This invention relates to wire connectors and their fabrication and particularly to connectors in the form of terminal lugs made of copper or aluminum.

Terminal lugs are normally used to fasten essentially round (solid or stranded) wires to bus bars having flat surfaces. The optimum material for terminal lugs is pure copper when such factors as cost, ductibility and conductivity are considered.

Small terminal lugs are normally made of copper and are normally cold forged. In this way, the high conductivity and ductibility of copper are used advantageously and the superior strength of cold worked material is available. In the past, however, large sized terminal lugs have not been cold forged because of the great compressive forces that are required to cause cold flow of the large quantity of material involved. The cost of machinery and dies capable of withstanding the extreme pressures required have always made this method uneconomical. Because of this, large lugs are usually made by casting bronze material. The conductivity of bronze is much less than that of copper. The bronze lugs, therefore, have inferior electrical characteristics when compared to copper lugs.

It is an object of the present invention to provide for improvements in large terminal lugs. It is a further object to improve the fabrication of large terminal lugs and similar articles from flat strip stock of pure copper or aluminum. Certain aspects of the invention involve the use of bending, stretching and drawing techniques, rather than cold flow methods. These techniques require far less force than cold forging and therefore the tooling and machinery are more economical.

The foregoing objects and others ancillary thereto are preferably realized by drawing part of a flat strip of metal in successive stages into a cup while another portion is left flat. The flat portion forms the tang of the lug. The bottom of the unformed portion of the cup is then formed to a spherical curvature. At this same time, the edge of the opening at the other end of the cup, where the transition from cup to flat tang occurs, is formed as a seat which may be a circular ledge, a crimp ring, or a ledge made up ofa number oflands. In this way, the diameter of the hole at the tang end of the cup is defined by the seat and is made smaller than the internal diameter of the cup. The spherically curved bottom portion is then sheared free and punched down into the interior of the cup to lodge against the seat where it is flattened and wedged within the walls of the cup. Holes are then punched, or drilled, vertically through the cup near the closed end to receive wires or cables. The open end of the cup is prepared, e.g., by cutting threads, so that a plug may be inserted to hold the wire or cable in place. A suitable hole may be drilled in the tang to produce a finished terminal lug of use in fastening wires and cable to bus bars.

All of the steps referred to in the preceding paragraph may be preformed serially in a multistation progressive die. The part is carried from station to station by means of a scrap train. This method requires a minimum of direct labor cost.

The above mentioned and other features and objects of this invention and the manner of obtaining them will become more apparent, and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates a flattened piece of copper or aluminum pre-shaped for use in the practice of the invention,

FIG. 2 is a perspective view showing a cup formed from the strip of metal ofFlG. 1,

FIGS. 3 and 4 are perspective views showing the cup at further stages of formation and more clearly showing the tang as well,

FIGS. 5 and 6 are perspective views in which FIG. 5 shows the lug following removal of the closed end and FIG. 6 shows how holes are placed in the tang and through the main body of the lug,

FIGS. 7A and 7B illustrate respectively a threaded plug and a piece of bare wire which are shown assembled with the lug in FIG. 7C,

FIGS. 8-11 are cross sectional views of a cup as it would be formed in four draw stages according to the invention,

FIG. 12 is a sectional view showing the effects of additional manufacturing stages in which the flange has been set and the closed end of the cup has been formed to a spherical curvature,

FIG. 13 is a sectional view of an embodiment of a terminal lug using the configuration of FIG. 12,

FIGS. 14A and 14B illustrate, in cross section and in a top view respectively, the effect of broaching a barrier shelf formed by three lands at the open end of the cup,

FIG. 15 shows in cross section the result of piercing the closed end of the cup to form a slug, flattening the slug and forming it against the barrier shelf,

FIG. 16 illustrates in cross section a combination of dies and punches used in forming the cup,

FIG. 17 illustrates, in partial section, a further stage in the formation of a cup,

FIG. 18 illustrates, in partial section, an anvil and a punch being used in shaping a terminal lug,

FIG. 19 shows in partial section a variation in the method for forming a terminal lug, and

FIG. 20 shows in partial section a further stage of the variation illustrated in FIG. 19.

Turning now to FIGS. 1-4 there are illustrated various stages of an exemplary series of steps involving drawing the original flat piece 1 of FIG. 1 through the stages of FIGS. 2 and 3 (plus additional drawing steps, if necessary) to form the cup 2 having a closed end at 3 and a tang 4, as shown in FIG. 4. FIG. 5 illustrates the results of a step following formation of the cup 2 of FIG. 5 in which the end 3 of the cup 2 of FIG. 4 has been punched out and pressed into and through the cup to seal the other end of the cup (not shown). FIG. 6 illustrates a further stage in which the interior of the lug has been prepared to receive a slug and a countersunk hole 6 has been made in the tang 4.

After the lug has been prepared to the extent illustrated in FIG. 5, it is finished as in FIG. 6. The tang 4 is pierced and countersunk as at 6 in FIG. 6. Holes are pierced through the cup 2 at 8 and threads 5 are applied to the interior of the lug. In the form shown in FIG. 6, the lug can receive a bare wire as at 10 (FIG. 78) through the holes 8. The wire can then be fastened in place by a threaded plug 12 (FIG. 7A) to produce an assembly as in FIG. 7C.

A variety of procedures for drawing flat piece 1 of FIG. 1 through a series of stages to produce a terminal lug having the degree of completion shown in FIG. 5 are illustrated further in the drawings in FIGS. 8-20. A first series of four drawing stages are shown in FIGS. 8-11 in which a series of punches and dies (not illustrated) of successively smaller size are used to draw a cup down to the form shown in FIG. 11. References may be made to the Metals Handbook" 8th edition, Vol. 1, published by American Society for Metals, Novelty, Ohio, and particularly to pages 709-717 for further details relating to the formation of cup shaped metal parts by the use of deep drawing dies in a press.

FIG. 12 illustrates in cross section the result of applying suitable punch and die operations to a cup formed like that shown in FIG. 11. It should be noted particularly that the end 3 of the cup has been reformed to a spherical curvature or Belleville top now labeled 3 and that a more definite and limited bend exists at 9 while the flange 4 and tang 4 are set.

The configuration indicated in cross section in FIG. 12 can be used to fashion a lug as shown in FIG. 13. In FIG. 13 a stranded wire at 10 is passed through holes at 8 punched through the cup. The wire 10 is held in place in the cup by a threaded plug or clamp screw 12.

FIGS. 14A and 148 show respectively in cross section and in elevation the results of broaching the lower barrier shelf to form a seat for a slug in the form of three lands L. Broaching may be performed with a suitable die and anvil as shown in detail elsewhere in this specification. FIG. shows in cross section the effect of piercing the closed end 3 of the cup (as shown in FIG. 14A) to form a slug and flattening the slug as shown at 3", with a suitable flat punch Pl, against the lands L and an anvil at A1.

FIG. 16 illustrates a different procedure for further shaping a cup such as that shown in FIG. 12. In this embodiment of the invention a cup 2 is placed in a pair of dies D1 and D2 and punches P2 and P3 are positioned. Pressure is then applied to the dies and punches to shape the cup as shown in cross section. By this procedure the cup 2 is shortened when the metal at is extruded upward to form a ridgelike ring.

FIG. 17 illustrates a manufacturing step in which the vertical circular protrusion or ridge at 20 (FIG. 16) is depressed or turned over by a punch P4 to form a seat for a slug in the form of a crimp ring at 21. The crimp ring 21 may be said to serve as a floor, a ledge or a seat for the slug 3" which is pierced at the same time by the punch P5. In FIG. 18, the punch P5 is shown to have pierced the curved closed end 3 forming the slug 3" and forcing it against an anvil A2 and against the crimp ring 21.

FIGS. 19 and 20 illustrate an additional way of forming a lug in accordance with the invention. In this instance, the cup 2 is pierced at its closed end 3' by a punch at P6 and pushed through the cup to abut against an anvil at A3 and against a ledge at L2 formed by action of the anvil A3 against the cup 2 and the die at D3.

We claim:

1. A method for forming a terminal lug comprising forming a cup by drawing a portion of a flat metallic piece in a series of steps,

shaping the closed end of the cup by imparting a curvature to each face of the end,

forming a ledge at the open end of the cup,

shearing free the closed end of the cup to form a slug,

punching the slug through the interior of the cup and into contact with the ledge, and flattening the slug into the open end of the cup to wedge it firmly within the walls of the cup and against the ledge. 2. A method for forming a terminal lug as claimed in claim 1 in which the method for forming a ledge includes breaching a plurality of lands to serve as said ledge. 3. A method for forming a terminal lug as claimed in claim 1 in which the step of shearing free the closed end of the cup to form a slug includes piercing the closed end with a die, and the step of punching the slug through the interior of the cup and into contact with the ledge includes flattening the slug against an anvil at the same time it is flattened against the ledge. 4. A method for forming a terminal lug as claimed in claim 1, in which the method for forming a ledge at the open end of the cup includes forming a ridgelike ring by subjecting the cup to pressure along its central axis and punching the ridgelike ring to turn it over and form a crimp ring to serve as the ledge. 5. A method for forming a terminal lug as claimed in claim 1, in which the method for flattening the slug to wedge it within the walls of the cup and against the ledge includes the application of force to the slug between an anvil on one side of the ledge and a punch on the other side of the ledge. 6. A method for forming a terminal lug as claimed in claim 1, in which the method for forming a ledge comprises:

placing the cup within the cradle of a die, and applying force on an anvil at the open end of the cup to form the ledge against the die.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US980945 *Feb 27, 1908Jan 10, 1911Automatic Electric CoElectrical binding-post.
US2185981 *Apr 10, 1939Jan 2, 1940Hygrade Sylvania CorpContactor base for electric lamps, tubes, and the like
US2223853 *Oct 27, 1939Dec 3, 1940Kearney James R CorpMethod of producing body portions of electrical connectors
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5862589 *Aug 6, 1996Jan 26, 1999Framatome Connectors Usa, Inc.Tubular wedge for an electrical wedge connector
US6726510 *May 15, 2001Apr 27, 2004Tyco Electronics Raychem GmbhCable lug
US7699669Aug 24, 2007Apr 20, 2010Ilsco CorporationScrew assembly for electrical connectors
DE10326004A1 *Jun 10, 2003Dec 30, 2004Volkswagen AgWater-resistant cable lug e.g. for electrical connections in vehicle, includes hollow-cylindrical part formed by multi-stage deep drawing from sheet metal
DE102004010779A1 *Mar 5, 2004Sep 22, 2005A & E Keller Kaltumformtechnik Gmbh & Co.KgFixing sleeve for cables and similar items has profiled hole section that can be used to grip cable
DE102004010779B4 *Mar 5, 2004Mar 22, 2012A. + E. Keller Gmbh & Co. KgHülse zum endseitigen Aufschieben auf ein Kabel oder Seil, sowie Verfahren zur Herstellung einer Hülse für die Aufnahme des Endes eines Kabels oder Seils
U.S. Classification29/882, 439/814
International ClassificationH01R4/28, H01R9/00, H01R4/36
Cooperative ClassificationH01R4/36, H01R9/00
European ClassificationH01R9/00, H01R4/36
Legal Events
Jul 25, 1985ASAssignment
Effective date: 19850629
Apr 22, 1985ASAssignment
Effective date: 19831122