Патент USA US3048660код для вставки
Aug. 7, 1962 J. w. ALLEN ETAL 3,048,650 ELECTRICAL. CONNECTIONS Filed Oct. 17, 1958 m 1 v’ ' E 5 “AW: \\\\‘<(\*Q\\\\\~ ‘ INVENTOR. JOHN h). RLLEN B DONALD E LERCH YGEORGE LAZIEGLER IR. United States Patent O??ce 3,048,650 Patented Aug. 7, 1962, 1 3,048,650 ELECTRICAL CONNECTIONS John W. Allen, Donald P. Lerch, and George W. Ziegler, Jr., Carlisle, Pa., assignors to AMP Incorporated, Har risburg, Pa. Filed Oct. 17, 1958, Ser. No. 767,878 5 Claims. (Cl. 174—90) The use of electrical connectors having ferrule-forming portions which are U-shaped in cross-section for forming electrical connections to electrical conductors is now wide spread, various methods of folding the arms of the con nectors about the conductors being used. Such connec tors have numerous advantages but suffer from the sub stantial disadvantage that no entirely satisfactory means of pre-insulating them has heretofore been found. Where pre-insulation has been required it has been necessary to use closed barrel type connectors. Among the objects of this invention are the provision 2 it is clearly desirable that the outer layer of insulation must not be ruptured during the crimping operation and it has been found that rupturing is particularly liable to occur when the ferrule-forming portion of the connector is made, as is common, from a substantially rectangular plane blank, which is bent up into a U-shape in cross section and presents a substantially rectangular side eleva tion. The reason for this is apparently the extrusion of the metal in the crimping operation which forms pro tuberances at each end of the edges of the arms of the connector; these protuberances rip and rupture the insulation. By making the connector from a circular blank we ?nd that we are able to avoid this rupturing and at the same time achieve more than mere point to point contact of the curved arms of the connector, because of the extrusion of metal into the angles between the two arms. The ferrule-forming portion formed from a circu lar blank will be U-shaped in cross-section and its side elevation a segment of a circle. of a pre-insulated strip of electrical connectors, a blank 20 The invention will now be described in greater detail for making the connectors, a method of crimping the con and by way of example with reference to the accompany nectors and a pre~insulated electrical connection. Other ing drawings; it should be clearly understood that these objects will become apparent hereinafter. A pre-insulated strip of connectors according to this invention comprises a U-shaped strip of a linear polyester having one arm of the U longer than the other, the inside edge of the longer arm and the outside edge of the shorter arm being chamfered, the strip carrying a coating of a heat and pressure-sensitive adhesive on its inside surface and having U -shaped ferrule-forming portions of electrical connectors sticking to the inside surface at regular inter vals. The preferred linear polyester is polyethylene therephthalate and in particular the material sold by E. I. Dupont de Nemours and Company Inc. under the regis tered trademark “Mylar.” We have found that the linear polyesters are the only plastic insulating materials that drawings are given purely by way of example and not limitation and that various modi?cations, alterations and variations can be made to the illustrated embodiments within the scope of this invention. In the drawings: FIGURE 1 is a perspective view of a strip of pre insulated connectors; FIGURE .2 is a plan view of a blank for making the connectors shown in FIGURE 1; FIGURE 3 is a section on the line 3-3 of FIGURE 2; FIGURE 4 is a perspective view of a connection made with a connector from the strip of FIGURE 1; FIGURE 5 is a section on the line 5—5 of FIGURE 2; FIGURES 6 to 8 are partial sections showing stages in the crimping of a connection; and are satisfactory; they combine good mechanical proper FIGURES 9 and 10 are perspective views of alternative ties with excellent electrical properties. embodiments. In accordance with the invention, a U-shaped ferrule Referring ?rst to FIGURE 1 a strip 2 of polyethylene forming portion of an electrical connector stuck to the 40 terephthalate is U-shaped in cross-section. One arm 4 of inside surface of a U-shaped strip of a linear polyester, the U is longer than the other arm 6. The inside edge the arms of the polyester strip being of unequal length, of the arm 4 is chamfered at 8 and the outside edge of the remainder of the inside surface having a coating of a the arm 6 is chamfered at 10. The inside surface of the heat and pressure-sensitive adhesive is crimped about an strip 2 has a coating of a pressure sensitive and heat cur electrical conductor lying within the U. According to able adhesive. At regular intervals along the length of this feature the connector assembly is forced by means the strip 2 connectors 12 are stuck by means of the of a substantially plane anvil into a semi-cylindrical, adhesive. The connectors are applied to the strip with heated, die so that the arms of the connector and strip are folded about the conductor and compressed together to give a connection substantially D-shaped in cross-sec tion and substantially voidless, the shorter arm of the heat and pressure. Each connector is made from a cir cular blank as shown in FIGURES 2 and 3. The blanks are formed by a progressive die forming operation from a strip of brass, the ?nal stage being the strip being gripped between the arms of the connector stamping of the circular ‘blank from the strip. Each blank and the longer arm being stuck to the shorter arm by the 14 has ?ve parallel grooves 16 running across a central heat from the die. Advantageously there is a series of plateau 17 from which the blank tapers down gradually connectors supported on a unitary continuous strip of 55 to its edges, which are thinner than the centre. linear polyester which is fed to present the connectors one by one to the die and anvil and in which each connector The blanks are formed up into U-shaped cross-section with the grooves 16 running at right angles to the axis of the U, before they are stuck to the strip 2. assembly is disconnected from the continuous strip by The arms 4 and 6 of the strip 2 have slits 18‘ at regular severing the strip while the connector is being applied 60 intervals between the connectors .12 to enable the strip to the conductor. An electrical connection between a ferrule of an elec trical connector and an electrical conductor lying within the ferrule forms a still further feature of the invention, to be handled with greater ease and to be Wound up on curved part of the connection has a longitudinal slit in which is held one side of a strip of a linear polyester. The connectors illustrated in FIGURE 1 are used for splicing two or more conductors together end to end or reels. The slits 1S_are of such a depth that they leave a connecting link between the units of the strip which is narrow enough to permit coiling but wide enough to pre according to which the connection is substantially D shaped and substantially voidless in cross-section and the 65 vent accidental breaking of the strip. for joining two or more conductors together at points This strip is wrapped around the connector ferrule and intermediate to their ends or for similar purposes. FIG overlaps itself to provide a continuous insulating sheath 70 URES 4 and 5 illustrate a splice connection between two in surrounding relationship to the ferrule, and the other insulated stranded conductors 20 and 22. The two con end of it overlapping the strip and sticking to it. Now, ductors lie side by side in the ferrule 24 formed by fold 3,048,650 3 ing the arms of the connector 12 and the arms 4 and 6 of the strip about the conductors. The arms 4 and 6 are also curled around the insulation of the conductors ance with the invention need not necessarily be circular shown in the drawing although the circular blank shown presents substantial advantages in the manufacturing process. It is, however, highly desirable that the longi 20 and 22 and form insulation supports 26. The operation of the crimping process and the detailed C1 tudinal edges of the connector be chamfered as shown and that these longitudinal edges be rounded, i.e. the construction of the connection will be apparent from FIG URES 5 to 8. In FIGURES 6 to 8 a connector is in position on an anvil 28 which has a substantially plane upper surface. The anvil cooperates with a semi-circular U-shaped connector should offer as a sector of a circle in side elevation. Thus, a connector in accordance ‘with the invention can be formed from ‘an oval-shaped, or a rec tangle whose ends have been rounded into sectors, rather than a round blank with the curved edges only having a chamfer. We claim: curled into the position shown in FIGURE 7; in this 1. A U-shaped sheet of a linear polyester having one position by virtue of the chamfered edges 8 and 10 the longer arm 4 slides over the shorter arm 6. Continued 15 arm of the U longer than the other, at least one of said arms being chamfered along its longitudinal edge, said forcing of the connector into the die 30 causes the shorter sheet carrying a coating of a heat-and-pressure sensitive arm 6 to be gripped between the arms of the connector while the longer arm is forced to overlap the shorter adhesive on its surface within the U, at least one electrical connector of U-shaped cross section disposed in said sheet arm. The die 30 is heated, for example by an electrical heat 20 and adhering thereto with its arms parallel to the arms of said sheet, the side edges of the arms of said connector ing element, not shown, mounted directly above the die cavity. The heat of the die activates the adhesive coating being rounded at their extremities and the edge portions on the inner side of the arms 6 and ‘4, and sticks the in of said arms of said connector having a tapered cross sec sulation to itself, to the conductor where the shorter arm tion, and said arms of said connector being devoid of sharp corners. 6 enters the ferrule and to the insulation on the con— ductors. The resulting connection is substantially D 2. A strip of polyethylene terephthalate U-shaped in shaped in cross-section and is forged to a substantially cross-section and having one arm of the U longer than voidless connection. Preferably, the crimping operation the other, the inside edges of the longer arm and the out is effected in two stages. The connector is compressed side edge of the shorter arm being chamfered, the strip tightly around the conductors in a ?rst stage and the 30 having a coating of a heat-and—pressure-sensitive adhesive pressure is then reduced while maintaining the connection on its inside surface and having electrical connectors die 36, having parallel lead-in surfaces 32 tangenial to the curved die surface. As the anvil 28 forces the connector into the semi-circular die the arms of the insulation are in the die. This permits complete softening of the ad hesive and ensures good sticking of the insulating mate rial ‘without the danger of extruding it from between the sticklng to the inside surface of the strip, each electrical connector having a ferrule-forming portion U-shaped in cross-sectlon to conform with the strip and its side eleva die and anvil. cc 01 tion being a segment of a circle. The grooves 16 running across the connector assist in _ 3. A ‘blank for making an electrical connector includ the gripping of the conductors and contribute to the tensile ing as a ferrule-forming portion a circular disc of metal strength of the connection. with its edge thinner than its centre and which tapers As the connector is applied to the conductors a shear gradually from a central plateau outwards and has a se blade removes the connector from the strip by cutting the 4.0 nes of parallel grooves across the central plateau. link joining it to the next connector in the strip. The 4. A crimped electrical connection between a ferrule strip is then advanced another unit into position on the of an electrical connector and an electrical conductor lying anvil for making the next connection. within the ferrule, the connection being substantially In the connector shown in FIGURES 1 to 8 the con nector is formed solely by the ferrule-forming portion and the connector is useful only for making splices. The invention is not, however, limited to this construction of connector. For example, the connector may have a ring tongue as shown in FIGURE 9. In the connector illus trated a ferrule-forming portion 34 is similar in construc an O tion to the connector 12, the base of the U being extended to form part of a ring-tongue 36. The strip of linear polyester again is coated with an adhesive and the con— nectors stuck to it, but in this case the link joining two connectors is formed by one arm 38 (in this case the longer arm). Each connector is removed from the strip during the crimping operation by severing along the dotted lines 40. FIGURE 10 shows a further embodiment in which the ferrule forming portions 12 are integral with rings 42 attached to each other in side by side relationship by means of slugs 44. In crimping terminals of this type onto wires, an automatic feeding means for the strip is advan~ tageously provided to feed the terminal to a position be neath the crimping press. While the invention has been herein disclosed with reference to a U-shaped ferrule adapted to be crimped onto a stripped wire, it will be apparent that the inven tion is also applicable to insulated wires, particularly Wires having one or more strands insulated with thin coverings of insulation such as varnish. In the latter case, the ser rations 16 will serve the function of penetrating the varnish D-shaped and substantially voidless in cross section in which’ the curved part of the ferrule has a longitudinal seam in which is held one end of a strip of a linear poly ester, the strip surrounding the ferrule and stuck to said ferrule, and ‘the other end of said strip overlapping said one end and sticking to said one end, said ferrule having been formed [from a circular blank and the edges of the curved part of said ferrule tapering towards said seam. 5. A method of making an electrical connection be tween two electrical conductors which comprises placing the conductors within a U-shaped electrical connector stuck to the inside surface of a U-shaped strip of a linear polyester with a heat-and-pressure-sensitive adhesive, and remalnder of the inside surface having a coating of the adhesive, the strip having one arm longer than the other and the edge of the longer arm of the strip being cham fered on its inside surface and the edge of the shorter arm being chamfered on its outside surface, said method com prrsmg the further steps of applying heat and pressure to curl the arms of said strip to position the shorter one of said arms under the longer one of said ‘arms, thereafter further curling said arms and additionally curling the sides ‘of said electrical connector towards each other until the sides of said ‘connector grip the shorter arm of said strip and the longer arm of said strip is wrapped around the joint formed by the sides of said connector and over laps the shorter arm of said strip, and then reducing the pressure applied to said connector and continuing to apply heat thereto to effect sealing of the overlapping arms of to establish electrical contact with the conductor as is said strip. known to the art. It should also be mentioned that a connector in accord 75 ‘ (References on following page) 5 3,048,650 6 References Cited in the ?le of this patent UNITED STATES PATENTS 1,397,040 2,703,997 2,786,191 Dillon _______________ __ Nov. 15, 1921 Sowter ______________ __ Mar. 15, 1955 Broske ______________ __ Mar. 19, 1957 2,800,638 Hammell _____________ __ July 23, 1957 2,845,606 2,863,132 5 Fuller _______________ __ July 29, 1958 Sowa _________________ __ Dec. 2, 1958 OTHER REFERENCES AMP pamphlet, received in Patent Office March 5, 1954 (page 3 relied on).