US2452932A - Electrical connector - Google Patents

Description

1943- J. o. JOHNSON 2,452,932:

ELECTRICAL CONNECTOR Filed April 10, 1944 IN V EN TOR. James 101 501!) ATTORNEYS the manufecture' and ferrule that these Patented Nov. 2, 1948 UNITED STATES PATENT OFFICE 2,452,932 ELECTRICAL CONNECTOR James .0. Johnson.

Lewisberry, Pa., assignor to Aircraft-Marine Products Inc., Harrisburg, Pa., 1 corporation of New Jersey Application April lo, 1944, Serial No. 530,313

2 Claims. (Cl. 29-15555) This invention relates to connectors for insulated electrical conductors, and particularly to terminals for such conductors which are oi the type having ferrules designed to be crimped into interlocking and good electrically conductive engegement with the stripped conductor ends.

in electrical terminals of various types provi-- sion is sometimes mode for holding the insulation ouoinst stripping heels beyond the part of the conductor that is'e'nclos'ed within nod crimped into interlocking relatlonto the ferrule oi the terniinnl. such means sometimes comprising insole.

.tlon clumping earsor lows stamped up out or the same sheet mote-rial or whiehthe teinai connector tongue jand the to or sol ferrule hove been termed. 7

An ohlect oi the present invention is to improve the construction of terminals oi the type lust descrlhed end to improve their method of opplioetion in order to insure s. tighter joint between the end oi the ferrule end the clamped end oi the insuio'tion; whereby to resist the entrance of moisture. end other foreign matter into this joint.

Another object of the invention is to simplify nectors or the type described.

Another ohiectis to facilitate the opplicotion of such connectors to the ends of insuloted conductors. u

To these ends the invention contemplates so spacing the insulation clamping lows iromthe lows- -mey he bodily-onset,

transversely to the ferrule unis, sumciently to bring the clamped insu ation into concen ric or illustrations and the explanations herein are given in order to acquaint others skilled in the art with this invention. and the principles thereof and a suitable manner of its dpplicatlonjin.practical useJso that others-skilled'in the art may be enabled. to modify the invention and to-ddspt it reduce the co'sto'i con-' and apply it in numerous forms, each as maybe best suited to the requirements of a particular use.

In the drawings,

Figure 1 is a perspective view of a terminal. 1 embodying the present invention, this view showing the terminal before attachment;

Figure 2 is a view in end elevation of a terminal ready for application to a, wire, having been formed from the blank of Figure l; and

Figure 3 is a view in side elevation of an insulated conductor having a terminal embodying the present invention attached thereto.

in the illustrative embodiment of the invention, the terminal is stamped out of sheet metal advantageously relatively. pure and therefore not readily machinable copper, for example, high'oom ductlvity, oxygen-tree electrolytic copper. The connector thus formed comprises a connector tongue i. which is shown somewhat enlarged st its end and provided with an opening i to re 7 celve o. connecting bolt, not shown; but this tongue is merely representative of the numerous connector devices which can be secured to the end of a conductor; the particular form is not 3 essential to the. present invention. A ferrule t is formed by rolling up laterally extending wings Sand l to form a cylinder the-tw ll fit ov r the stripped end or the conductor with which the terminal is to be used. Before rolling up the metal to form the ferrule, grooves t are preferably formed by impressing that face only of the metal which is to .form the innersurface of the ferrule;

I 'l hesegrco esnnd the intervening ribsextending nnnullnrly:ahoui;the axis of theitflnished ferrule;

serve to provide additional interlock when the ferrule is crimoed onto the conductor. Theseam t'foed by the meeting edges of the rolled up material is preferably brazed to prevent spreading of the edges when the ferrule is crimped onto the stripped end of the conductor, 'as shown in Figure 3, and also seals the' joint against ingress of foreign matter and corrosion. This brazing may conveniently be efiected in the manner described in the copending application Serial No. 546,835.

The sheet material of which the tongue 2 and ferrule t have been formed preferably continues beyond the end of the ferrule remote from the tongue 2 and there is provided with insulation clamping jaws l2 and it. It will be noted that the jaws It and ill have theirends IS' and. i8 tapered toward the opposite sides of the respective jaws so that they will overlap each other smoothly when the jaws are pressed down to embrace and clamp the insulation, as shown in Figure 3.

type are used is usually size and insulation thickness auaesa From an inspection of Figures 1 and 2 it will be seen that, when the terminal is first formed and the ferrule I and the clamping jaws l2 and I4 are rolled up from the sheet metal, the centerline of connection both of the jaws l2 and i4 and of the ferrule to the body of the terminal will all lie substantially on a common straight line. If the insulation itself had nothickness this would be the best relation; However, the insulation on conductors with which terminals of this of substantial thickness so that if the jaws were to be closed without odsetting there would be a sharp bend in the central conductor it! where it is pulled down over the end of the insulation 20 to enter the ferrule 8. This could be compensated and avoided by preformlng the neck 22 with a bend corresponding to the thickness of the insulation 20, but this adds to the expense. of manufacture, and the resulting shoulder interferes with the smooth threading of the wire into the ferrule. Moreover, such a preformed terminal is suited only to one thickness of insulation; thus requiring different dies and a separate inventory for every combination of wire with each type of terminal tongue.

In accordance with the present invention this neck 22, which connects the jaws l2 and I4 with the ferrule 8 and tongue 2 is of sufficient length so that the laws I 2 and I may be bodily offset, transversely to the axis of the ferrule 8, a sufficient distance to bring that part of the conductor i0 which lies within the insulation into coaxial alignment with the ferrule 6 or, in other words, to insure concentric alignment of the clamped insulation and of the ferrule-enclosed stripped conductor end, when the parts are assembled as shown in Figure 3, but it remains flat and aligned with adjacent portions of the ferrule B and support i2-l4 until after the connector has been assembled on the wire. The required bend in the neck 22 is then formed by the same operation by which the'jaws l2 and I4 are closed onto the insulation 20 and the ferrule 6 is crimped onto the bared wire l0.

It will be understood, of course, that the support l2ll could be offset bypre-forming of the neck 22 before theinsertion of the stripped conductor end l0 into the ferrule 8; that is, the terminal may be delivered to the user in this form; but even then by use of my invention the terminals can be re-formed upon application to fit various sizes of insulated wire. ously, however, the offsetting of the support i2- i4 is effected simultaneously with the crimping of the ferrule 6 into interlocking engagement with the conductor end i0 and simultaneously with the closing of the jaws l2 and H to bring them into clamping engagement with the insulation 20. This may be done by a tool suitably designed for the purpose, such, for example, as that shown in the copending application of Vernon E. Carlson, Serial No. 455,033, filed August 17, ,1942, Patent No. 2,359,083.

When applying the connector to an insulated ,wire, the end is first stripped of its insulation for a distance approximating the length of the ferrule 6. This end is then threaded into the ferrule, which is readily accomplished with my invention by guiding it along the bottom of the channel formed by the support portion 12- and the neck portion 22 (best shown in Figure 2). The wire is pushed home so that the edge of the insulation abuts the edge of the ferrule 0. The connector with its wire in place is then placed Advantage- 4 between closing and crimping dies as set forth Carlson Patent No. 2,359,083 and the dies closed.

Since the closing dies for the insulation support and the crimping dies for the ferrule are mounted in fixed coaxial relation, their closing onto the connector automatically bends the neck 22 to effect coaxial alignment of the ferrule and support portions. Moreover, since this bending occurs after the initial closing of the jaws l2l4 onto the insulation it draws the insulation axially closer to the ferrule 8 at the same time that the compression and coining of the ferrule is extruding it longitudinally toward the end of the insulation 20. Thus a tighter joint is formed between the ferrule and insulation which resists entry of corrosion and even tends to resist pressure leakage where the wires pass through pressure bulkheads, etc.

It will be observed that in the closing and crimping operations there is a sequence which follows from the geometrical relations involved.

First there is a bending over of the ends l6 and i8 to embrace the wire, these ends being engaged first in the upper die while the lower dies engage only the areas of the ferrule which are to be crimped. The distance of separation, axially, of the opposing pressures results in some bending down of the neck 22 where it joins the ferrule 2. The arcuate, trough-like form of the neck, however, provides stiflness to resist such bending until ends l6 and i8 and closed down and the upper die engages the ferrule at the areas tobe crimped. This causes jaws l2 and H to reach axially as far as possible along the wire as they are first closed into embracing relation. Near the end of this action the crimping dies engage and begin to flatten the ferrule 6. This flattening causes a further bending down of neck portion 22 as the ferrule is flattened so as to force the conductor M to an axial position. Further closing of the .same time the neck 22 is bent back adjacent the edge of the support portion i2-ll so as to bring this support portion into axial alignment with the ferrule 8; and this results in crowding the support .portion with the insulation embraced therein toward the ferrule 6 at the same time that the compression of the jaws l2 and I4 is extruding the insulation toward the ferrule and'the coining of the ferrule in the crimped areas is extruding it toward the insulation. All these actions com-- blue to give a tightly compressed end to end joint as well as a mechanically strong engagement and a low resistance stable electrical connection.

From the foregoing description it will be seen that the improved terminal permits such a close and permanent abutting of the clamped insulation 20 against the end of the ferrule I and against the shoulder formed by the bending of the neck' 22 in the offsetting of the jaws l2 and I4 that a joint between the ferrule end and the insulation is formed and maintained which is substantially impervious to moisture or oth r foreign matter that might otherwise tend to enter the connection at this point and eventually bring about its destruction.

What is claimed as new is:

1. In the art of attaching an electrical connector to the stripped end of an insulation sheathed electrical conductor, that improvement which includes the steps of: forming from a flat blank a connector having -a tubular ferrule for the conductor; positioning the upstanding Jaws 10 around the insulation sheath adjacent its end,

the bight of the U-shaped portion, the neck, and the portion of the ferrule opposite the longitudinal seam being in alignment; and then while the aforesaid portions are in alignment, bending the jaws around and onto the insulation sheath while simultaneously offsetting the neck to bring the insulation sheath and the ferrule into coaxial alignment; and then crimping the ferrule onto the stripped conductor; said bending offsetting ,n and crimping steps being performed as a part of a single operation.

2. In the art of attaching an electrical connector to the stripped end of an insulation sheathed electrical conductor, that improvement which includes the'steps of forming from a flat blank a connector having a tubular ferrule for receiving the stripped conductor end, said-tubular ferrule having a closed longitudinal seam, said connector. having upstanding, open U-shaped Jaws for embracing the insulation sheath adjacent the stripped end and having a substantially straight, narrow intermediate neck integrally connecting the ferrule and jaws; positioning the connector ferrule over the stripped end of the conductor; positioning the upstanding jaws around the insulation sheath adjacent its end, the bight of the U-shaped portion, the neck. and the portion of the ferrule opposite thelongitudinal seam being in alignment; and then while the aforesaid portions are in alignment, bending the jaws around and ontoz-gthe insulation sheath while simultaneously offsetting the neck to bring the insulation sheath and t e ferrule into coaxial alignment; and then crixn ing the ferrule onto the stripped end of the conductor and closing the jaws tightly onto the insulation sheath; said bending, offsetting, crimping and closing steps being parts of a single operation.

o. JOHNSON.

REFERENCES crrnn The following references are of r ord 1 1t file of this patent;

UNITED s'ra'r-yas PATENTS Number Name Y Date 838,729 Lockwood Dec. 18,1908 1,181,513 Ericson- May 2,1918 1,899,254 Bear Feb. 28, 1933 2,142,818 Jacobson Jan. 3,1939 2,275,163 Thomas, Jr, Mar. 8, 1939 2,280,351 Pentold et al Apr. 21, 1942 2,288,918 Parker July 7, 1942 2,359,083 Carlson -4.-- Sept.'26;"194 4 2,371,469 Rogoi! Mar. 13,1945 2,379,567 Buchanan July 3,, 1945 I 2,385,792 Carlson Oct. 2, 1945,

OTHER 'la'za'm 6E8 AMP Solderless Wire Devices, Aircraft-Marine Products, Inc., Elizabeth, N. J. Page 4.

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