US2681440A

US2681440A - Electrical connector

Info

Publication number: US2681440A
Application number: US257080A
Authority: US
Inventors: Robert C Swengel
Original assignee: Aircraft Marine Products Inc
Current assignee: TE Connectivity Corp
Priority date: 1951-11-19
Filing date: 1951-11-19
Publication date: 1954-06-15
Anticipated expiration: 1971-06-15

Description

June 15, 1954 R. c. swr-:NGEL 2,681,440

ELECTRICAL CONNECTOR Filed Nov. 19, 1951 T'lc'l.

T1 :1.11 b. /J m BY d @www ATTORNEYS:

Patented June 15, 1954 UNITED STATES @GFFICE ELECTRICAL CONNECTOR Robert C. `Swensel, iYork, lia., aassienor to Aircraft-Marine Products IncgHarrisburg, Pa., a corporation ,of New Jersey Application November 19, 1951, Serial No. 257,080

11 Claims. (Cl. 339-223) This invention relates to electrical connectors and particularly to improvements v,in such con.- nectors whereby the conductive parts of the connectors are insulated, for the purpose among Others 0f Dreventngnflash-cyer between connectors. The invention `further relates to insulated electrical connectors having particularly strong and secure engagement not only between the connector and electrical `conductor but also between the insulating member or covering and the electrical conductor.

Modern industrial and military `electrical equipment creates a demand for electrical con.- nectors offering the utmost in dependability, particularly among other things that the terminals be insulated, that is that the connector be insulated ffor ,a vdistance back along the electrical conductor. The purpose of this insulation, among others is to prevent creepage current on the surface of the insulation and ashover between adjacent connectors, which might otherwise result 'from voltage surges, ionizing conditions in the atmosphere or dampness etc., or from accidental movement of the connectors too close to one .another or to other conductor elements. Such leakage from electrical connectors could, of course, result in failure of equipment at a critical time and this is of cou-rse particularly signicant in connection with military equipment, railroad signal equipment, aircraft,ietc. Inthe past even insulated connections 'have in some instances been subject to such failure.

fThe primary ,object of the invention is to provide `an electrical Aconnector having improved insulation characteristics. Another object `is to provide a connectorhaving improved attachment of the insulating member or material tothe `electrical conductor to provide secure engagement therewith, and With shielding thereon when used. Another object is to provide an increased insulated `distance from the conductive parts of the connector, increased creepage distance and greater resistance to iiash-over from the `conhector.

Although in the accompanying drawings I have shown a preferred embodiment `,of my `invention and have described -the same andsvarious .modincations thereof `in this specification, it iis to be understood that these are not intended tobe e-xr haustive but, on the contrary, are Jclfiosen Yfor Ethe purpose ofillustrating the invention in order that others 'skilled ,inthe art may so ifully vouderstan.d the invent-ion, its principles and the application thereof that they :may embody it and .adapt fit f of Aa `yvire.

2 numerous forms, each as may be `best suited vto therequrernents of its particular use.

Further objects and numerous advantages of the inyention will become apparentfrom the iollowng detailed description and `annexed drawing wherein;

Figure 1 is an electrical terminal -haying an enlarged insulating tube and a supporting `metal han@ within the tube.

Figure 2 is similar'to Figure 1 but With the end of the metal band spun back oyer the insulating sheath.

Figure 3 is a sectional viewtof a preferred form of the intention wherein there is a metal supporting band spaced lQm the sleeve `around the ferrule..

Figure 3a is a vfragmentary sectional viewshow.- ing a modincation `of Figure 3.

Figure 3b isla fragmentary sectional view show`- ing .another modiiication of Figure 3.

Figure 4i is a sectional View taken along line LA f Figure "3.

"Figure f5 is a perspective View of the `form of the invention `of `Figure 13 crimped onto 4the Lend :Bientot is a .modified .form of the invention applied to a shielded wire in Aa way to isolate the shielding ,from the terminal- :Fisuso 'i is a perspective VView of :the arrangement o f gFgurelG crimped onto a wire.

Fiel-iro `8 is a fragmentary View axial sect-ion of a connector similar to that ,of `.Figure V3, but with extended :wire supporting portion and with on .insulated shielded Wire inlolaoe therein ready for orimpina As sstiorth inthe foregoing objects, tno invention soolss to prov-ido an improved insulatedioonneetcr, by reason among `'other things `of provid,- ing yarnoyel and improved manner and means of securing rtv-ire therein. -In addition, the 4intentieyn provides more iapp-ropriate and `eiectiy` `,support for the insulation wh-ioh normally is the torm of a sheath .oVer `the Wire.

Referring :i0 Figure l of the drawings, there Y is :shown an oleotrioal connector comprising ,a

ferrule I2 and a connector-tongue portion t4. `'The ferrule 1.2 is `tor-med A:by material 'rolled into oy1 i r1 drical tor-m with longitudinal abutting edges nhicnfmay bsbrozod together. `liuiooral iones..- enaies @a plastic tube engaging .forrule 1 2 and advantageously oomonted thereto, :in aooordanoo with the invention .disclosed and .claimed :in lmy copensiine :application Serial 251,466 tiled Qotober i6., .11;951., VnowPatent No. -2 ,654,852'3, issued .Qotoberfa 12253. fine emisor tube It :issemareed as shown at I8 to receive an insulated wire, the end of which is stripped and crimped in the ferrule I2, e. g., by a crimp of the type disclosed in the patents of Buchanan Nos. 2,379,567 and 2,554,813, or of the Carlson Patent No. 2,359,083, or of the I-Ioltzapple application Serial No. '73,946 filed February l, 1949. The portion I8 is enlarged to permit reception of an insulated (unstripped) portion of the insulated wire within the end portion of the insulating tubing and this may be crimped so that the tubing securely engages the insulation of the wire.

Within the enlarged portion I8 is a metal band 20 which when crimped securely engages the insulation of the wire. The type of crimp may be one well known in the art. The portion I8 is of somewhat larger diameter than the insulated wire and the preferred type of crimp is one wherein upper and lower portions of band 2B and portion I8 assume a curved contour and side portions are more or less parallel, as in said applications of Carlson and Holtzapple, respectively, thus providing secure engagement with the insulated wire. The band 20 serves the purpose of providing support for the insulating tubing I6 before it is crimped; and the tubing I6 being securely cemented to it, it helps to hold the exterior of the wire when the connection is crimped on. The band 20 enables the tubing to assume and retain the desired shape and to serve its intended purpose most effectively.

The plastic tubing I6 may be formed and applied in any of various ways according to the various methods used in the plastics art.

Figure 2 shows an arrangement similar to that of Figure 1 wherein the metal support band 20a within the enlarged portion I8 of the insulating tubing I6 extends back over the end of the tubing as shown at 24. As in Figure 2 band 20a is securely attached by crimping to the insulated wire and the insulating tubing I8 is cemented to the band. The turned over portion 24 further assists as a retainer for the insulating tubing I8, securing it in position and holding it against changing form in response to plastic memory, e. g., if the terminal should become overheated.

Figure 3 is a view of another advantageous form of the invention which provides a very effective insulated connector. Numeral I2 indicates a ferrule having a connector portion I4. ferrule is formed of pure electrical copper by rolling a blank stamped from the sheet material into cylindrical form such that a longitudinal butt joint is formed along the top thereof. Over the ferrule thus vformed is tted a seamless copper V(or other metal) sleeve 28 which extends .beyond the end of the ferrule. The sleeve 28 is necked or indented as indicated at 30, and crimped over at its opposite end as indicated at 32. Numeral IIb indicates a plastic sheath applied around the outside of sleeve 28 and extending beyond it for purposes of insulating the terminal. Inside of the extension I8b of sheath |619 near its end is a metal band 2Gb which serves as a support for the Vend of the sheath I 6b and to which the sheath is securely cemented.

In use the ferrule I2 is crimped to a bare part 34 of an electrical conductor in a manner well known in the art and the extending portion I8 of the sheath I6 and the band 20 are crimped in a known manner to an insulated part 36 of the wire as shown at 31, the band 20 securely engaging the insulation. The sheath I8, being securely cemented to the band 20 maintains the same shape as the band. (I use the reference The numerals generically to refer to the corresponding elements of the modified forms of Figures 2-8, as well as the form shown in Figure 1.)

Figure 3a shows a modification of the structure of Figure 3 in which the band 20c is on the outside of sheath Ib instead of inside, but provides support for it in the same manner as in Figure 3. The band is fitted on and cemented to the sheath I8?) as in the previous embodiment.

Figure 3b shows another modication wherein a stepped band is used instead of the simple band 23h. The inner portion of this band is used like its counterpart 20h of Figure 3; while the outer portion 38 can receive an outer insulation, where used over the shielding. When the inner portion and the end of sheath I8b are crimped, e. g., as shown in Figure 5, for the embodiment of Figure 3, those two parts are interlocked, and the shielding is securely engaged. When the outer portion 38 is crimped it securely holds the outer insulation of the wire, holding it against pulling back so as to expose any part of the shielding and also avoiding any unsupported area where repeated flexing might cause a fatigue failure in the wire.

Figure 5 is a perspective view of a terminal as shown in Figures 3 and 4 when it has been crimped onto the end of an insulated wire. As will be observed, the conductor is shown of the multi-strand type (although it might be solid or single strand). The end of the ferrule I2 and the sleeve 23 and 4sheath Ib are crimped as shown to a more or less elliptical shape by a compression forging process as already known in the art. The crimping tool leaves twin indents on each side with a transverse ridge between each pair on the upper and lower sides respectively, as shown. The opposite end of the sheath I 8b and band 2Gb are crimped onto an insulated part of the wire as shown at 31, preferably by a conned compression die of the type shown in said Carlson patent. The resulting construction is a thoroughly insulated connector wherein the insulation is firmly secured to the connector and canj not slip therefrom. The connector is furthermore fully protected from flash-over in that the metal band 23h secured to the outer end 0f the insulating sheath is not connected to any conductive part of the assembly.

Referring to Figure 6 of the drawings, there is shown another form of the invention applicable particularly to shielded conductors, wherein the connector itself is insulated from the shielding; yet the shielding is secured thereto without taping and shellacking. In Figure 6 the ferrule I2 and connector are secured to the plastic sheath Id by cementing it to the sleeve 28d and/or crimping the latter thereon. Metal sleeve 23d engages the ferrule I2 and the outside of the end of sheath I8cZ. Sleeve 23d is necked or annularly indented as shown at Sd. The band 28d in this case extends beyond the end of sheath ISd to receive and engage shielding or other part of the wire.

The ferrule I2, sleeve 23d and sheath IBd can be crimped onto the wire 34 and insulation 35d in a manner corresponding to that of previous embodiments or in other ways known to the art. The wire of Figure 6 is of the type having braided metallic Wire shielding 55 which is normally grounded. The metal band 29d is secured to the end of the sheath iSd as in the other gures, and after insertion of the wire into the connector this band is crimped onto the adjacent ends of sheath ISd and shielding material 56, e. g., as previously described, so as to firmly secure the shielding to the connector,

Figure 7 is a perspective View of the arrangement of Figure 6 after being thus crimped to a Wire. As Will be observed, the arrangement provides a very effective insulated connector particularly for insulated wires having shielding thereon, the arrangement thoroughly insulating the shielding from the terminal itself but all of the parts of the assembly being very securely attached to the Wire.

Where the wire to be connected is composed of several coaxial layers the sheath i8 and/or the band 2li may be stepped in additional steps to support or secure successive layers. Thus with the structures of Figures 1 or 3, the plastic I8 may be extended farther and enlarged to a greater diameter to receive the next largest layer, With or Without a corresponding extension and enlargement of the supporting band 2B; or the band 2l! may be thus extended and enlarged beyond the end o the plastic sheath I8. Or a larger tube of metal or insulating plastic can have one end iitted and secured to the outer end of such a connector and its other end of a size to receive and hold one of the layers of the Wire.

This is illustrated by Figure 8 wherein a larger insulating sheath 58 is cemented onto the end of sheath |81) of Figure 3. This connector is shown assembled with, but not yet crimped onto a multilayer wire having a central conductor 34, insulation 36, shielding 5B and external insulating layer 60.

I claim:

1. In an electrical connector, in combination, a ferrule of malleable metal having an extending connector portion, said ferrule comprising malleable conductive material, a coating of nexible insulating material of the type adapted at room temperature to transmit Without failure forces sufficient to forge said malleable metal together with a conductor into secure engagement, said coat being permanently secured on said ferrule, and a malleable metal band secured to the insulating coat near its end remote from said eX- tending connector portion, the ends of said band being axially displaced from the near end of said coat and insulated from all conductive parts in contact with said ferrule.

2. In an electrical connection the combination as defined in claim 1 Which further includes an insulated wire, said ferrule being forged onto a central conductor of the Wire in electrical contact therewith and said band and the portion of the insulating sleeve secured to it being crimped into engagement with a portion of the Wire where its insulation remains intact.

3. In an electrical connector, in combination, a ferrule forming portion of malleable metal having another connector portion extending therefrom, an extension of stiiily flexible insulating material secured to said ferrule at its open end, said insulation extending beyond all metal in conductive relation to the ferrule, and a malleable metal band secured thereto in an area at the end of said extension and spaced beyond said ferrule portion.

4. In an insulated electrical connection, in comblnation, a metal ierrule, a shielded, insulated electrical conductor having an end secured in pressure engagement in the ferrule, a coat of insulating material secured to the ferrule and extending therebeyond, the shielding material on said conductor terminating beyond the said ferrule and spaced by said coat from all parts in conducting relation With the ferrule, and a metal band secured to an end portion of the insulating coat and surrounding said shielding material and crimped to securely engage it.

5. In an insulated electrical connection, in combination, a metal ferrule, a shielded, insulated electrical conductor having an end secured in pressure engagement in the ferrule, a coat of insulating material secured to the ferrule and extending therebeyond, the shielding material on said conductor terminating beyond the said insulating coat and spaced from all parts in conducting relation With the ferrule, and a metal band engaged over adjoining portions of the insulating coat and shielding material.

6. In an electrical connector, in combination, a ferrule having an extending connector portion, an insulating coat engaged over the ierrule and extending therefrom, and a metal band secured thereto Within said extending portion and spaced from all parts in conductive relation to the ferrule.

7. In an electrical connector, in combination, a ferrule having an extending connector portion, an insulating coat engaged over the ferrule and extending therefrom, the extending end of said coat being enlarged, and a metal band secured thereto within said enlarged portion and spaced i from all parts in conductive relation to the ferrule.

8. The structure of claim 7 wherein the metal band extends beyond the end of said coat and back over its exterior.

9. In an electrical connector, in combination, a ferrule having an extending connector portion, an insulating sleeve engaged over the ferrule and extending therefrom, the extending end of the sleeve having a metal band iitting thereover and spaced from all parts in conductive relation to the ferrule, the band being secured to the sleeve.

l0. The structure of claim 9 wherein the ferrule is securely crimped onto a bare portion of an electrical conductor and the tube and metal band are securely crimped onto an insulated portion of the conductor.

1l. An electrical connector comprising a cylindrical malleable metal ferrule, a tubular insulator extending coaxially from one end of said ferrule, a coaxial sheath engaging adjacent portions of said ferrule and insulator securing said ferrule and insulator together, and a cylindrical malleable metal band surrounding said insulator at least near its end remote from said ferrule, said band extending beyond the remote end of said insulator.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 2,316,267 McLarn Apr. 13, 1943 2,405,111 Carlson et al Aug.. 6, 1946 2,410,321 Watts Oct. 29, 1946