USRE23688E - Electrical connector - Google Patents

Description

July 21, 1953 w. s. WATTS Re. 23,688

ELECTRICAL CONNECTOR Original Filed Dec. 14, 1943 INVENTOR M14441 J %/77J.

F M M Q ATTORN Y5 Reiuued July 21,

ELECTRICAL CONNECTOR William S. Watts, Roselle, Ni J., assignor to Ahcrait Marine Products, 1110., Elizabeth, N. 32, a corporation of New Jersey Original No. 2,410,321, dated October 29, .1946, Serial No. 514,216, December 14, 1943. Application i'or reissue October 28, 1947, Serial No.

7 Claims. (Cl. 339-213) Matter enclosed in heavy brackets appears in the original patent but forms no part of this reissue specification; matter printed in italicsindicatcs the additions made by reissue.

1 I This invention relates to an electrical connector, and more particularly to a connector of the type which is adapted to be applied and secured to electrical conductors by crimping of a ferrule onto a conductor received therein.

Connectors of the general type of which this invention is concerned, have been in commercial use prior to my present invention and are disclosed, for example, in the application of Stephen S. Buchanan, Serial No. 421,408, filed December 3, 1941, issued as Patent No. 2,379,567 on July 3, 1945, and Serial No 474,935, filed February 6, 1943; and in the application of Carlson and Freedom, Serial No. 459,624, filed September 25, 1942. In the terminals as illustrated in these prior copending applications a ferrule is formed of a size adapted to receive the bare conductor,

e. g., the end of the stranded wire of an insulated I cable, and over this is applied a metal sleeve extended beyond the open end of the ferrule so as to receive and support an insulated portion of the insulated cable. As commonly applied this extended sleeve has been crimpcd onto the insulation at the same time that the ferrule is crimped onto the bare portion of the conductor. This, for example. is disclosed and a suitable tool therefor is shown and described in an application of Vernon E. Carlson, Serial No. 455,033, filed August 17, 1942.

In many cases it is desirable that the exposed portions of the terminal of the ferrule should be non-conducting, either so as to avoid dangerous or disagreeable shock to persons making adjustments or repairs while the terminals are carrying relatively high voltages or to prevent accidental contact with nearby terminals or other conducting parts. Although it has been common practice prior to my invention, with other types of terminals, to provide insulated sleeves, it has not heretofore been considered feasible to use an insulated sleeve on a terminal which is to be crimped upon a wire. I have now discovered that, if an insulating sleeve is made of a tough stiifly flexible, more or less rubbery plastic of about the same order of thickness as the metal of the ferrule, e. g. from about a tenth up to about three or four times the thickness of the metal, depending upon the toughness and. other properties of the plastic, the resulting insulated ferrule may be used in substantially the same manner and crlmpcd with the same types of tools as those made entirely of metal. e. ts, as described in the atom-mentioned oopending application. More over, I have found that rubbery plastics or the type which may be subjected. to severe deformation and which would recover only slowly after such deformation may be used with advantage, according to my invention; and thus, to the extent that such plastics may be damaged during the crimping operation, the damage is repaired by the gradual recovery of the plastic after its release from the crimping dies. This is of particular advantage when it is desired to mold or crimp the sleeve onto the insulation at the same time that the ferrule is crimped onto the wire. Plastic, materials adapted to be thus formed onto the insulation tend to cut or extrude to some extent, irom under the crimping die in the areas where the ferrule is crimped onto the wire, and thus may expose at certain points the conducting metal of the ferrule. The gradual recovery of the plastic will cause it to creep back over such exposed surfaces and thus give a satisfactory insulation-of the entire ferrule.

In order to prevent a similar recovery of the portion of the sleeve which serves as the insulaticn support, the material of which it is made may be chosen with respect to the surface material of the wire so that the two adhere strongly when pressed together; or. if this is not convenient, a surface coating on the interior of the sleeve may serve as an adhesive for this purpose.

Although I am giving below and showing in the accompanying drawing, preferred cmbodimcnts of my invention and suggesting various modifications thereof and alternatives, it should be understood that these are not intended to be exhaustive or limiting of "the invention, but on the contrary, are given. for purposes of illustration and explanation, in order that others skilled in the art may fully understand the invention, the principles thereof, and the manner of application for practical use, and may thereby be snabled to embody and adaptthe invention in numerous forms and with numerous modifications. each as may be best adapted to the provisions of a particular use.

In the accompanying drawing:

Figure l is a View in longitm cal section oi a terminal embodying my invention, ready for application to an insulated wire;

Figure is a porsp tive View on a reduced shown in Figure 1, applied and crilnpcd onto a wire;

Figure 3 a. view ill longitudh'ial section, sir-oi Karly to that in Figure 1, bodiment of my invc Figure a is diagrumr View in side clovation illustrzrtlm; one method of making the terminal shown. in Figure cases 3' 4 As shown in Figure 1, a metal portion of the of insulating material, a metal sleeve II is used terminal it may be substantially identical with of substantially the same form as that disclosed that described in the copending application menin the application of Freedom and Carlson above tioned above. For example, it maybemade from referred to. Between this and the ferrule II, sheet metal having a flat tongue portion ii and 5 howevenwhen the two are assembled, is inserted a ferrule portion 12 made by rolling into cylina layer of insulation Its, whereby the outer sleeve drical form, with the butting edges lateral or ll, although of conducting material, actually is tensions integral with the tongue portion .l I. not in conducting relation to the circuit. This This metal portion can advantageously be made terminal may be applied and crimped onto the of dead soft annealed copper whereby it may be wire in exactly the same manner as indicated in crlmped onto the wire and coined by the crimp- Figure '2. During the crimping operation, the,

ing tool so as to form asubstantially solid mass outer sleeve it tends to relieve somewhat the sewith the inserted wire and have a permanent Vere strain imposed on the plastic insulating maunion therewith, substantially without springterial and to oppose any tendency of the plastic to back 15 flow laterally out from under the crimping die.

Over the ferrule i2 is the insulating sleeve II In Figure 4. I have shown diagrammatically which tightly engages the ferrule. Depending one method of making the terminals of Figure 3. upon the material used, this may be a press ilt, In this case a flat sheet of plastic is placed or, advantageously, if as indicated above, the maover a drawing die It in which the sleeve II is terial is one whichmay besubiected to severe fi ted and suitably held. The ferrule II is then deformation and will tend to recover gradually Dressed down into the sleeve II (with or without its original size and form, the sleeve may be preliminary drawing Operations) to perform the stretched to a larger diameter, fitted over the eeve "a. The ferrule i2 carries with it the ferrule, and then allowed to shrink onto it. This M81310! which s formed and drawn y subject matter is more particularly described and the ie t and p essed suflici tiv to a low the claimed in the copending application of Frank'Ja wo parts to enter tog r. I1 the Sheet lib is Sowa, Serial No. 560,785, filed October as, 1944. e nyl plas su h a is described a v This process can be facilitated by stretching at the tendency of the material to recover gradually room temperature and warming the sleeve to a w e 0! i n th the stre hed matehigher temperature to accelerate its recovery. fli l radually w farther into the B1306 Likewise, if it is desirable to hold a supply of betwen the sleeve ll and-the ferrule i! to the the stretched ferrules for some time, they may full extent permissible by e di erence between beicnul d t delay t recovery their diameters. This can be hastened as indi- I have found an advantageous material for this by Warming the terminals a te avpurposeto be a vinyl chloride vinyl acetate co- 8 n flBBc b fld a r00!!! temperature even polymer, slightly plasticized with any of the usual llighlily chilled. I plasticizers, e. g., tricresyl phosphate. Such ma- A the assembly p fl d ore terial is commercially available in the form of 1" his process of shrinking is complete, the extruded tubes [and may, for example. be obend which is stretched over the end of the fertainedunder the tradename Irviiite" from the 40 rule if may be punched out or this may be left Irvington Varnish Works, Irvington, New Jersey] in Place and punctured when the stranded wire on the interior of the extendedend of the is inserted. sleeve II, I have shown a coating of adhesive ll. Although the terminal shown in Figure 3 has This may be any known relatively stable adhesive the advantage that in its finished appearance it compatible with the materials used for the sleeve is substantially identical .with the terminals alit and the materials commonly used for surfacready in wi e comm rcial use. the terminal of ing insulated wire. I have found the pressure- 8 1! 1 is t e u t e adv a e that the sensitive adhesives, made from degraded rubber stiflly flexible plastic sleeve allows some yield such as are commonly used in adhesive tapes, are with flex nfi of the insulated cable, so that sharp satisfactory for this purpose. 5D bending is avoided: and, due to its flexibility and In the use of this terminal the end of an insuits slow recovery, it also tends to damp vibrations lated wire is first stripped to expose the central in the wire and thus to protect the actual conductor of twisted stranded wire. This is then crimped connection in the ferrule from this deinserted in the end of the sleeve II, the central structive influence. stranded conductor extending on into the ferrule 5 I claim:

If, while the insulation itself extends only into 1. An electrical connector of the type intended thesleeve l3 abutting against the ends of the to be crimped onto a wire and including a soft ferrule, The assembly may then be crimped. in metal ferruleand a normally risid tube of tough a tool such as that shown in the copending apand stiiily -iiexible insulating plastic tightly smplication of Veron E. Carlson above referred to; so bracing said ferrule and covering the outer surwhereupon the ferrule 12 and the surrounding face thereof, said tube having a resistance to cold portions of the sleeve it are flattened and coined plastic flow not significantly less than that of the onto the wire, whereas the outer end of the sleeve metal of said ferrule, whereby said tube can II is crimped and formed so as tightly to embrace transmit sumcient crimping pressure to the ferthe'insulation of the wire and to be cemented as rule from a crimp tool to crimp the ferrule thereto by the adhesive ll. Whereas the sleeve against a conductor by plastic flow in the metal I! will tend to recover so as to repair any breaks them! without crack ng the tube or otherwise whichimay possibly have occurred during the interfering with its mechanical and ectrical rsevere crimping of ferrule II, the adhesive ll fectiveness.

tendsto hold the outer portion of the sleeve in 2. An electrical connector as defined in claim its pressed and deformed condition as shown, 1 wherein the plastic of said tube is of the type counteracting the tendency of the sleeve to rehaving plastic memory, which tends gradually to cover its wider form. recover its original form after severe deforma- In' Figure 3, I have shown an alternative struction. ture, wherein instead of using a simple sleeve ll 76. 8 An electrical connector as defined in claim 1 wherein said tube extends substantially beyond the end of said ferrule whereby to receive and support an insulated portion of an insulated wire and has a coating of non-drying pressure-sensitive adhesive on the interior of said extended portion of the tube, whereby said extension may be secured to the insulated wire.

4. An electrical connector as defined in claim 1 wherein a thin metal sleeve surrounds said plastic tube.

5. A connector for use in a crimped joint comprising a cylindrically shaped metal body portion having an open end for receiving a conductor therein, an insulating cover thereon, said insulating cover having the physical properties of permitting an indenting tool to be applied easternally to the insulation and causing the metal body underneath to be indented in the form of a recess to a conductor therein, and of substantially retaining the shape of the recess in the insulation after the tool has been withdrawn.

6. A connector for use in a crimped joint comprising a cylindrically shaped metal body portion having an open end for receiving'a conductor therein, an insulating cover thereon, said insulating cover having the physical properties of toughness, flexibility and plasticity, whereby to transmit from an externally applied indenting tool to said metal body portion beneath it a localized force, suflicient to indent said body onto 1 a conductor within said body in an area beneath said indenting tool, and of substantially retaining the shape of the recess produced by such indenting tool after the tool has been withdrawn.

7. A connector for use in a crimped joint comprising a cylindrically shaped metal body portion having an open end for receiving a conductor therein; an insulating cover thereon, said insulating cover having the physical properties of permitting an indenting tool to be applied ea:- ternally to the insulation and causing the metal body underneath to be indented in the form of a recess to a conductor therein and of initially retaining the approximate shape of the recess in the insulation alter the tool has been withdrawn but having a tendency to return, at least to some extent, to the shape it had prior to indenting.

WILLIAM S. WA'I'IS.

References Cited in the file of this patent or the minimal patent UNITED STATES PATENTS Number Name Date 2,035,911 Mucher Mar. 31, 1936 2,148,392 Ransome Feb. 21, 1939 2,173,668 Smith Sept. 10, 1939 2,297,336 White Sept. 29, 1942 2,338,524 McCabe Jan. 4, 1944 FOREIGN PATENTS Number Country Date 847,814 France July 10, 1939

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