US 2904619 A
Description (OCR text may contain errors)
Sept. 15, 1959 E. w. FORNEY, .1R 2,904,619
SHIELDED vWIRE CONNECTORS Filed July 23, 1954 3 Sheets-Sheet 1 1 /l//li INVENTOR.
Edn-r LA). Fovnelvdr.
wlmi-MM Sept. 15, 1959 E. w. FORNEY, JR
SHIELDED WIRE CONNECTORS 5 Sheets-Sheet 2 Filed July 23, 1954 #www a. M
n man ..3 mv q eem a:
IN VEN TOR. Edgar w. Fornelj, d?. BY W, r LM Sept. 15, 1959 E. w. FQRNEY, JR 2,904,619
SHIELDED WIRE CONNECTORS Filed July 23, 1954 3 Sheets-Sheet 5 IN VEN TOR.
Ed an' W. Fome JT. BY g 5' Z .Il we United States Patent O SHIELDED' WIRE CONNECTORS Edgar W. Forney, Ir., Harrisburg, Pa., assignor to AMP' Incorporated Application July 23, 1954, Serial No.y 445,277 11s claims. (ci. 1mi-ss) The present invention relates to electrical` connectors which are crimped onto shielded electrical wires to make permanent, mechanically andelectrically secure connections and to the resulting connections and the method and apparatus for making such connections. The connectors described as embodying the invention provide connections both to the. inner conductors of shielded wires and to their electrically conductive shields, while maintaining them insulated one from the other. This application a= continuation-impart ofl .my prior `copending application, Serial. No.. 3105,205., filed August 1:9, 1952 now abandoned.
Among. the important advantages of the presentinvention, are those resulting. Afrom the fact that the connectorsy described are integral.. No loose pieces are required to make connections. Av splice. between twof shielded wires. is completed merely by crimping one. of the connectors described in tou-r places.`
Formerly, in` many cases connectors` for shieldedwireswere of the separable typel involving complicatedl screwmachine parts,Y often requiring soldering to the inner conductor or shield. Such. connections are bulky,rv ex* pensive, and diiicult to make; In other cases,- connections for shielded wires. have been` made by strippingv back the shielding a distance, stripping the intermediate insulation from end. portions of the inner conductors, twisting and soldering the conductors; together, then care'- fuliy insulating. thisjoint, and finally joining the two wire shields together by a short length of wire soldered toA each shield. The central conductor was. often. left substantially Unshielded'. at the. junction.A Where shielding was required, aloose'piece of braided shielding was slipped over. one of the wires before the connection` was madeV and was bridged between'y the two shields adjacent the connection and soldered. thereto.t Such shielding is difiicult to handle and .readily becomes loose or'frayed. Extreme care is, required to solder. the shielding on' the wires without seriously damaging` the intermediate insulation, for the large thermal` conductivity ofl the shieldingusually requires the application. of considerable heat in soldering.. Such soldered connections are bulky and' awkward; they may be left improperly shielded, and the skilled labor time required is considerable, regardless of how such connections are made.
Crimped connections for shielded wires have been suggestedv` but have required the use of a1 number of sepa-` rate pieces. Prior crimped connections. have requiredthat the connection be built up step by step, with considerable manipulation of loose pieees and whenthe connection was completed'V there was nosolid insulation vlayer between the inner conductor and shield in the region of the connection. y i
In order to facilitate theD making of shielded-wire connections and ones wherein the inner conductor and the shielding of the shielded wire are posi-tively insulated tion.
2,904,619 Patented Sept. 15',` 1.959l
and quickly crimped to grip and connect both' the inner conductors and the shielding.
The described embodiments of the present inventionV automatically provide continuous shielding of the ce'ntral conductor as the connection is made. These con-A nectors provide compact, strong connections which have a minimum eifect on the characteristic electrical impedance of a shielded wire.
Among the advantages of the present invention are those resulting from the fact that noncollapsible sleeves are inserted under the shielding of the shielded wire in order to back up the forces applied to the shield and protect the insulation of the wire duri-ng crimping. These inner sleeves have their ends slanted to facilitate` 'sliding under the shield and to present an effectively larger opening into which to insert the baredend of the inner conductor of the shielded wire being connected.
l AnV advantage of one of the connectors described is that the end of the outer sleeve projects beyond the end ofthe inner sleeve. This projecting end is adapted to becrimped closely around the shielding beyond the 'inner sleeve so as in effect to embrace firmly the' wire insulation. The result is to clamp the inner conductor of' the shielded wire at its entrance into the connection, thus preventing any vibration from travelling therealong into` the connection. As shown, theA end of the outer sleeve in this connector is folded back a short distance inside, the resulting double thickness giving rm support to the inner conductor. Advantagecusly, stepped dies are used to produce a firm support for the inner conductor by this extending endy portion of the outer sleeve.
Yet another advantage of this invention is the provision of a connector, and connection made therewith-,- which enables easy visual inspection of the connection between the` inner conductors.
In one of the described connectors, the window in* the outer sleeve through which the oprator can determine: whether the ends' of the inner conductors have been fully inserted into theconnector, is generally rectangular in outline, thereby providing a View ofthe ends of the iii-'f ner conductors extendingl the full width of the connec- This helps in making a properv connection' and greatly aids awiring inspector, for in many cases he' does not have to twist thev wire in ordery to get a goodlook through the window at the ends of the' inner conductors.- Also, the rectangular shapev of the window is well adapted to coacty with the connector-locating fingers us'ed in cer-- 1 transparent plastic and is depressed tof form a pane Withfrom one another, I provide unitary connectors which can be used without! disassembly, and into: which shielded wires, with end portionsv strippedv to expose the` inner conductors, may readily be inserted andztlie assembly easily in the window closely adjacent the desired position of 'the' inner ends of the conductors to provide a clear vie'wof' the ends of the conductors and so that they may be se'e'rfrom a further lateral position. The longitudinal e'dg'es ofthis window in the outer sleeve of certain' embodiments of the connector described are slightly turned in during indenting` of the depressed plastic pane to assist in main taining the depressed areay from springb'ack and to help hold plastic insulation layer within the outer slec'z'fe'f.V
A further advantage of the certain connectors de-V scribed is thatthe outer sleeves have semi-circular crimp's therein over the inner sleeves and positioned near t'he endsof the insulation sleeve to hold the whole connector: assembly rmly together. j
Also, the connector is adaptedv to have a smaller size shielded wire is connected to a larger one.
A- furrher advantage of one of the described connectors' is that' the insulation sleeve between the inner and outerl conductive ferrule has a thickened central portion, th`er`cby increasing the strength of the connector and the breakdown voltage of the completed connection.
The various other advantages and aspects of the present invention will be in part pointed out and in part understood from the following description considered in conjunction with the accompanying two sheets of drawings, in which:
Figure 1 is a perspective view of a completed connection between two shielded wires, the connection being formed by a connector embodying the present invention;
Figure 2 is a perspective and sectional yview of the connection in Figure 1 taken along the line of 2-2 parallel to the axis of the connection of Figure l;
Figure 3 is an exploded perspective view of the parts of the connector used in making the connection in Figure 1;
Figure 4 is a perspective sectional View taken longitudinally through the uncrimped connector and showing a shielded wire inserted into the right end of the connector in position to be crimped;
Figure 5 is a cross sectional view taken along the line 5 5 in Figure 1 showing the crimped connection to the inner conductor of a shielded wire;
Figure 6 is a cross sectional view taken along the line 6-6 in Figure 1 showing the crimped connection to the shield braid of a shielded wire;
Figure 7 is a transverse sectional view, on enlarged scale, taken along the line 7-7 of Figure l through the window portion of the connector;
Figure 8 is a longitudinal sectional view, on enlarged scale, illustrating the center portion of the uncrimped connector of Figure 3 showing the serrations on the inner ferrule;
Figure 9 is a perspective view of one of the stepped dies used to make the connection to the shielding on the wire;
Figure 10 is an axial View of the upper and lower dies in partially closed position as seen from the lange end;
Figure l1 is an axial sectional view, in enlarged scale, of an end of the connection of Fignire 1 being completed by the dies of Figures 9 and l0;
Figures 12, 13 and 14 show the embodiments of the present invention disclosed in my above copending application, as follows:
Figure 12 is a longitudinal sectional view through a connector prior to crimping with the end of a shielded wire shown properly positioned for crimping;
Figure 13 is a partial longitudinal sectional view of another embodiment of the invention, this view being similar to the right side of Figure 9, but with the shielding of the -wire shown partially broken away and in section and with a shield-supporting sleeve shown inserted under the shielding and Figure 14 is a cross sectional view through the shieldgripping crimp used with the connector of Figure 12.
In Figures 1 and 2 is shown an easily made, permanent connection formed by crimping an integral con-v nector 11 onto the ends of a pair of shielded wires 10, each including an inner conductor 12, an intermediate insulation layer 14, and an outer conductor shield 16, shown as braided wire. To join the inner conductors 12 of the shielded wires, the connector 11 has an inner conductor ferrule 20 (see also Figures 3 and 4) including two cylindrical ferrule portions 22 which are held. in electrical attachment and spaced end-to-end relationship by a joining portion 24. Each of the ferrule portions 22 is adapted to be slid over the bared end of an inner conductor 12, as shown most clearly in Figure 4, and to be crimped thereto by crimping forces applied to the outside of the integral connector 11 to form crimps 25 (Figure 5). Advantageously, there is no need to disassemble the connector or to build up the connection step by step to make the connection. The inner conductor ferrule 20 may be rolled from a blank stamped from sheet metal stock, the resulting seam 23 being shown in Figure 5.
To insulate the inner conductor ferrule 20 from the other portions of connector 11 and automatically to insure an eiective continuation of the insulation 14 throughout the length of the connection, an insulation sleeve 32 of tough transparent plastic is placed over ferrule 20 (Figure 3), and is held in position by external serrations 21 on the outer surfaces of both ferrule portions 22. In assembling Ithis plastic sleeve 32 and the inner ferrule 20 into an integral component, the ferrule 20 is press tted into the plastic sleeve. Then the ferrule is induction heated to soften the plastic in contact with the ferrule portions 22, causing the softened plastic to flow into the serrations to produce a mechanicallock between the ferrule and plastic sleeve. Sleeve 32 is of a material suiciently tough to withstand the compression forces of a crimping operation without undue loss of resistance to voltage breakdown. In a commercial form, it is of transparent nylon.
Generally, the materials suitable for use in insulation sleeve 32 are those that can withstand the pressures during crimping of enclosed metal connection assemblies and may be from a class of insulation materials which are very tough and suliiciently malleable (capable of being pressure-formed without rupture) at ordinary temperatures to be compressively deformed and set during the crimping operation. The workable materials have been found to reside in that group of plastics commonly referred to as rigid, including such superpolymers as vinyl chloride, slightly plasticized, vinyl chloride-vinyl acetate copolymers, vinylidene chloride, and nylon. Softer materials may tend to be squeezed out of place too readily. Another advantage of my connector is that the outer shield ferrule 34 protects insulation sleeve 32 from direct Contact with the crimping dies and tends, by its frictional contact, to retard the extrusion of the insulation material. Thus it permits a thinner or softer sleeve 32 to be used than customarily would be used in insulated connectors without such an outer ferrule, to reduce the overall diameter of the connection.
The form of crimp 25 (Figure 5) used in compressing the central conductor ferrule portions '22 by means of pressure applied -through the tubular insulation sleeve 32 is important in providing the desired electrical and mechanical properties and the preferred crimp is particularly protective of the sleeve 32, as described in detail hereinafter.
The outer surface on the ferrule portions 22 should be fairly smooth, as shown in Figure 5, to protect the insulation sleeve 32 from local areas of unduly high pressure during the crimping operation. The serrations 21 are of the type leaving lands of trapezoidal cross section so that the outer surfaces of ferrule portions 22 remain in effect substantially smooth.
The central conductor ferrule 20 is made of electrically conductive and malleable metal; soft copper and vbrass can readily be used. The malleability should be such that the yferrule 20 can be compacted against and coldflowed into intimate contact with the conductors 12. High conductivity, such as that of copper, minimizes the size of the ferrule 20.
The inner surfaces of the ends of the ferrule portions 22 advantageously provide funneled entrances 28 to their bores 30 to help in sliding in the bared ends of the inner conductors 12, which is particularly helpful when these inner conductors are finely stranded. It is also desirable to have the bores 30 of the ferrule portions 22 provided with transverse serrations 31, similar to serrations 2l to increase the tensile strength of the connection.
A malleable outer conductive shield 34 forms the casing for the connector, with its ends extending beyond the ends of insulation sleeve 32. In completing the connection, the ends of outer sleeve 34 are each triply folded in two places andv collapsed inwardly to embrace the shielding 16 on the wire, as described in detail hereinafter.x rhe shielding 16 is backed up during the crimping operation by a relatively rigid shield-supporting' vsleeve 35 of drawn seamless tubing secured within each end of the connector. Each of sleeves 35 has an enlarged inner end fitted into an annular recess 37 to grip the reduced outside diameter of the end of the insulation sleeve 32, which is tapered at about a 30 angle for a short length on its outer surface to aid in sliding the sleeves' 35 thereon.
As seen most clearly in Figure 4, a shoulder 38 formed by thetransition` between the enlarged and reduced ends of sleeve 35 forms an annular abutment for stopping the shielding 16 and may advantageously be used for sliding the shielding 16 back from the end of the wire asthe wire 10 is inserted into connector 11. Abutment 38 properly positions the end of the shielding within the' completed connection, f maintaining the desired spacing between ferrule 20 and shield 16. The outer ends 39 ofshield-supporting sleeves 35 are cut olf at an angle of about 75 to the connector axis and have an inside diameter approximately equal to the inside diameter of the inner surfaces 33 of the ends of the insulation sleeve 32 extending beyond the ends of the ferrule portions 22, to form an effectively continuous bore for receiving the wire insulation '14. Preferably the inside diameter of ends 39 is only slightly larger than the insulation 14 so as firmly to embrace insulation 14 (see Figure 6) after the shield-gripping crimp is made, for example, as shown by the dotted outline (Figure 4) of the end 39 of the sleeve 35 in the right side of the connector 11.
The slanted ends 39 of sleeves 35 are helpful in furnishing a lead so that ends 39 may readily be slid underneath shield braid 16 adjacent the intermediate insulation 14, without any snagging of the shield braid thereon. Also, with the ends 39 slanted, shown at about a 75 angle, the elliptical opening into sleeve 35 is somewhat longer than its actual inside diameter, which further aids in the insertion of the ends of conductors 12 and their insulation 14. To help in the assembly of the wires 10 and connector 11, the elliptical openings in slanted ends 39may face in the same direction as window 40.
As shown in Figures 2 and 4, a particular advantage of connector *11 is that after crimping the slanted ends 39 of the supporting sleeves 35 do not project beyond the skirt 42 on the ends of the outer ferrule 34. Thus, when the wire 10 is subjected to a sideward pull or is bent over adjacent the connection, the shielding 16 on the inner side of the bend is subjected to a compressive force to form a radius so as to protect the insulation sheath on the inside of the bend, while the shielding 16 on the outside of the bend is under tension from the closely adjacent grip of the crimped skirt 42 and resists the bending force, making the bend in the shielded Wire more gradual, to provide further protection.
The extending end of the skirt 42 is folded back to produce a double thickness bead 49 which is crimped down firmly against the shielding beyond the end 39 of theinner sleeve 35 as shown in Figure ll and described hereinafter in detail. The inner surface of shoulder 38 abuts the end of sleeve 32, thus holding sleeve 35 firmly in place against the force exerted by the shielding on the outside of shoulder 38 as wire 10 is inserted.
As mentioned above, insulating sleeve 32 is transparenty and a central window aperture 40 is provided in outer sleeve 34 adjacent the opening in ferrule 20 and opposite to the joining portion 24. It is rectangular and extends substantially across one side of the connector 11. The inserted ends of the inner conductors 12 may be readily seen through window 40 to make certain they are properly inserted.
The area of the sleeve 32 extending across the window 40 forms a plastic pane 43. In assembling the connector, the sleeve 32 is formed around ferrule 20 in tubular form and then is inserted into the outer ferrule 34. The window 40 initially extends less than half way around the circumference of the outer sleeve. After assembly ofthe parts of Figure 3, a ilat edge extending transversely of'the connector is used to indent the pane 43 flat (see Figure 7) over its full width and the two longitudinal edges 41 of the outer ferrule 34 extending parallel to the axis of the connector are rolled over onto the opposite edges of the pane 43 as shown most clearly in Figure 7. These rolled over edges 41 help to secure the outer ferrule 34 and the sleeve 32 together as an integral unit and help hold the pane 43 depressed.
The exploded view in Figure 3 shows sleeve 32 as it appears after assembly inside of the outer ferrule 34. Prior to assembly the sleeve 32 would not have the depressed 'pane 43.
The extreme ends of the outer shield ferrule 34 are flared outward, at least on their inner surface, and advantageously may have a full flared skirt 42 as shown in Figure 4, tovprovide afunneled entrance to their central bore 44. These funneled entrances 42 facilitate the insertion of the wire shields 16 into the shield ferrule 34 soithat as the shielded Wire is inserted the funneled entrances 33 and 28 guide the bared ends of inner conductors 12 into the ferrule portions 22, and the skirt 42 gathers in the end of shield 16, causing it to strike abutment 38. This enables the easy insertion of the shielded wire while preventing the inward movement of the braided wire shield 16 beyond abutment 38.
The whole connector 11 is held rigidly together by pairs of wide semi-circular crimps 47 which grip the enlarged inner ends of the sleeves 35 near the abutments 38 and help to align the sleeves 32 and 35 after their initial assembly -into the outer ferrule 34. These at crimps 47 may be run about half-way around the top and bottom of the sleeve 34 near the shoulder 38 in the braid-supporting sleeves 35.
In order to simplify the connection of shielded wire, I have developed a novel method which in many applications obviates any preliminary cutting back of the braidedwire shield. If there is any insulation over the shieldbraid it is, of course, stripped back a ways from the end of the shield-braid. This method consists of gripping the shielded wire a distance from its end in one hand and sliding the shielding back from the end with the other hand. With the intermediate insulation 14 (see Figure 4) thus exposed, this insulation 14 may then be severed and removed from an end portion of the conductor 12 by convenient insulation stripping means. Thereafter, when the shielded wire is inserted into one end of a connector as described, the insulation 14 is allowed to enter sleeves 35, but the shield 16 must slide onto it while insulation 14 slides into the connector until it reaches a position adjacent the restricted Iregion near the end of ferrule portion 22.
The bared ends of conductors 12 are inserted a bit beyond the adjacent ends of the ferrule portions 22 in order than the ends of `the conductor may be clearly seen through window 40. This is advantageous in ascertaining that a connection has been properly assembled before crimping, as well as in inspecting completed connections.
When both wires 10 have been inserted into the connector 11, it is pressure-formed or crimped in four places, 48, 25, 25, and 48, respectively, longitudinally spaced therealong to form a permanent connection as is shown in Figures l and 2.
Different types of crimps are preferred for gripping inner conductors 12 and for securing the shield 14. Referring to Figures 1 and 2, the central areas 25 of the shield ferrule 34, adjacent window 40 and overlying-the central conductor ferrule portions 22 are advantageously crimped to a attened, generally elliptical cross-sectional shape as shown in Figure 5. The advantage of this elliptical crimp, made with smoothly curved die surfaces confined at their sides during crimping, is that it maintains Ya substantially even thickness of the insulation sleeve 32 while the ferrule portions 22 and central conductors. 12A aref compacted tightly together. This crimp is. more: fully disclosed' and? isclaimed' inl the copending applicationof Clyde No.. Holtzapple, Serialir No. 73,946, tiled February 1, 1949, andassignedlt'of the sarneassignee astthe vpresent invention.
'Elie'. outer shield ferrule 3.4 ist advantageously crimped by av crimpi- 48,10.' collapsey the skirted: ends 42 firmly against-i the braided; shields, 1'6 andi to..` griprthee. shields. 16 as shown in Figurel 6.. The crimp 48'.showrncollapses= the shieldferrule inwardly at; sideportions 511:- and`forms. and compactstop: and bottom portions 52 aroundv the braided shielding 161 In. this. fashion. the; braided'. shielding. is rmly gripped between the shield ferrule.34.fand the shield support i without. appreciably.v deformin-g. the shield supporty or. reducing. the thickness vofthe intermediate insulation sheath 1.4.fo1changingits circular shape. This crimp 48- is particularly advantageousn-.orming connections. with connectors.` in. which; the. end. of. shield ferrule=341is generally. considerablyI larger than thezshield braidto he received.therein,.for example, where. afull skirted ilare 42: is .provided .on theends. offouter sleeve. 34.
rPhe crimp 48 includes projecting re-entrant folds 68 and? an inner. folded junction 7.0, thus producing. a triply folded region on opposite sidesofftheferrnle.. The adyanf tage of forming this crimpv isthat. Ii am able .torc'ollapse a shield ferrule onto .aflexible metallic. Wire shieldmerely by impressingl itl between two laterally eoniinedsdieA surfaces.. as described inl. myv said priorcopending applicattion. and toA get compresison. between. thez inner folded l-111ctions170 and. thewire shieldlt.- which compression actuallyis acting in.af.direction perpendiculantofthecomf pression forceofthe dies.V Thus, the-Wire; shield. 16. is compressed; between theV shield -fernile 34 andztlreintenmediate insulation sheath 14. about-substantially all. of its. circumference without imposing. high-ry pressure onthis part of; my cormectionY assembly. This in'. turn'. is; im@ portant because highrimping. pressures would. tend: to buckle the braid supports33r and thento. extrude; thin, and otherwise weaken the,y intermediate insulation; sheath 14;
The connection tortheshieldbraid as showninrthefpre: ceding lgures is crimped by'. the.. upper and.S lower dies and 84, respectivelyshown in Figuresv 9,. 1.0, andi 1l. The upper die includes twof at, crimping. shoulder sur.- faces 86 on. either side; extending perpendicular to the direction-fof; closure of the dies..
Betweenthe shoulder surfacestC extends two.v concave cylindricalgcrimpingsurfacesi 8.8' and-90. having the: same transverse extent, denedrbytheedges 91.. The; concave surfaces 9,0 has. an effective radiusf about; 20fto; 5 (ispercent smaller than the radius of. the surface-883. depending upon the connector dimensions, so that it extends; up further intofthedie 82, leaving acresentishaped step 92. The lower die 84S hascrmping surfaceswhichz are-identi.- ca-lfwith the upper die andfaresimilarly numbered, except that: the,v lower' die' additionally includes: two; spaced. up: wurdly extendinglegs 9,4.' onreachside which provide: uni.- formlyspaced at side walls 96 for, conning. the. skirt 42 during crimping. The smoothly curved portions. 90 press the skirt` 42` into conformingpressure: contact` with the;` shield .braidllwhile ,the at vregions:andthe edges 911frictionally pull the skirt 42K around opposite sides. of the shield braid: 16;. thus: acting. with.theparallel conning surfaces 96 to buckle the skirt 42 and formi. the; opposed tr'iplefolded regions 50 as-.shown in l-igurey 6..
At the same-time the moresha'llowconcave: surface 88 crimps the beaded edge -491rmly downt. against the shield braid lrbeyond the end-.3.91 ofthe inner sleeve. firmly to conne theinsulation layer. andi conductor 12 at the region ofentny into the connection.. 'Ehe resulting con.- finedl areas. 98'2in the insulation'. layer. 14a advantageously damp. out any. vibrations in'. the/.inner conductor 12E and prevent; them from entering: the. connection; The extra thick-'nesslin'A the bead-491 causes. the outer end portionl of the nnerriold. 7.0'. to extend"` in'- towardi the conductor` 12 somewhat further than the. resti off the fold` so` that the confined: regions 98: effectively extend' completely around-.theconductor 1-2 enhancing-the desired: damping support action by theinsulation14.. v
The. dies 82. and 84. are shown. as= being' laminated; formedby pairs of: parallel plates, 1-00fand1102', and1104 and. 106,. respectively, fastened together by.v means not shown to move as integral dies. 1'
Among. the other advantagesv ofconnector` 11l isV that itisl relatively small in size and: isf readily adapted to a range. of wire sizes. Also, it. may be used ytoconnect different. sizesof wire inits opposite. ends. Eonexample, the. inner ferrule 20 can accommodate a range ofv three sizes of wire, such1as 18.through= 22. 'Ihe-.fullskirts 42 can accomodate. a wide rangeof'sizesofl shieldinglt, and whileA shield-.supports 35 are generally enabled to support amore limitedrange of shieldl sizes', connector 11` is adapted toreceive. a widerange. of sizes-of'r supports 35.
In. a.. commercial.l form, sleeve.3.4. and ferrule 20: are made; from annealedrk copper, while shield-supports 33 were made from 70/3.0 ne. grain cartridge brass. 1A hard, stress. relieved for one hour at. 475i. I?.
For usewith shielded wires having inner conductors 12 in thesize range from 18` to 22, the. following dimensions and. sizes for connectorA 11i may. be usedto produce highly. satisfactory connections. Sleeve: 34 may havea wallthickness. of .010 inch, a length. of 1.5.15 inches, an inside diameter of.- .197 inch, and an outside diameter atr themouth of skirt 42' of .285 inch. Inner sleeve. 20 may.` be about a half an. inch long, for example, being .5.08: inch. long with an inside diameter of at least .061 inch and anoutside diameter ofnomorethan .136.inch. The insulation. sleeve 32 may. have. an oven-all. length of 1.015.y inches, with.the enlarged center portion being somewhatA longerthan. ferrule 2.0,. for example, being .515- inch long with the overhanging end. portions of're.- duced diameter each being about aquarter of an. inch long, and the. length. of the. external taper being. .O62 inch. 'Ihe wall thickness ofthe enlarged center portion of sleeve 32: may be in the range. from .028A to..03*l inch depending upon the tolerances. of the ferrule 20: and sleeve 34.
The shield supports 33 may be rabout .395i inch long with their enlarged end adapted to fit snuglywithin the end of sleeve; 341 The length. of the. enlargedpolftion may be about .1.87 inch long. and thelengtlr offthe. re.- duced portion.45y may be about' .2.08v inch. Its=wall.thick ness. is about. .01 inch and-l the inside diameten of the reduced. end 4,5 is inthe range fromabout .09.0140v .120 inch, depending upon the.. diameter of the; insulation 14 with which they are to be used. I. now. prefer. to .cut oi the end 39 of the inner sleeve 35 at an angle.. of about to the connector axis, but a. more graduallv inclination may be obtained,. if desired, by using an angle in the range from about. 45 to 75 for example, an angle of 60v0 has advantages for some applications., In. some instances it is desirable to have theend 39 cutoff parallel with the head 49 on the skirt 42.
In Figures 12,. 13, and` 1-4, are shown other embodif ments. of the. present. invention. Figure. l2. shows aauni.- tary connector 11a generally similar to. connector 11. For convenience, portions ofv connector-s 11a performing functions: similar to. connector 11 have. the same reference numeral with the sutlix a. 'Ihecylindricalferrule portions 22a are enclosed in seamless (drawn) sleeves 26', which sleeves comprise part-4 of. many. standard. types of ferrules. These sleeves. 26- are a means of: providing a very smooth outer surface on the ferrule portions 22a and when used are considered'. part of. the. ferrule. portions 22a in they further discussion. andI in the. accompanying claims along-with any other means for accomplishing the same result` (eg. havingA ferrul'eportions 22a drawn rather than rolled, or using carefully brazel1 and polished ferrules, etc.)a
The insulation sleeve 32a is a length of plastic tubing of one of the tough plastic materials discussed above with its ends projecting beyond the ends of the ferrule 20a. To hold ferrule 20a firmly within sleeve 32a, a pair of spacing tubes 36 are held in abutting or closely adjacent end-to-end relationship with each of the extreme ends of the ferrule 20a by means of pressed detents 57 in the shield ferrule 34a and tubular sleeve 32a which impose suiiicient pressure on the spacing tubes 36 to hold them securely in place.
The length of these tubes 36 is such that, when so held, their extreme ends coincide with the ends of the sleeve 32a to provide transverse annular abutments 38a spaced inwardly from each end of the shieldlferrule 34a. The spacing tubes 36 are of nonconductive material, preferably being short lengths of extruded plastic tubing which are quite stiff at ordinary temperatures. These tubes have various functions, the provision of the annular abutment 38a as a shield stop advantageously in cornbination with the ends of the tubular sleeve 32a, being their primary function. The spacing tubes provide a high dielectric, high breakdown voltage, and longer current creepage path between the central ferrule 20a and the wire shielding 16a which is abutted against the annular abutment 38a. These tubes 36 also form guides for the intermediate insulation sheath 14a which help locate the central conductor :12a in the central ferrule 20a during assembly of a connection.
Some type of shielded wire may have a protective outer coating of insulation 18 as shown in phantom lines in Figure 12 and in some circuits the shielding 16a of such wires may be operated at other than the potential of the chassis on which the shielded Wire is located. In a situation such as this, the shield ferrule 34a may be enclosed in an outer sheath 19 as shown in phantom lines of the tough, rigid, and substantially malleable insulation material which would remain undamaged after the crimping operation. In order to make the connection, external insulation sheath 18 is stripped back from the shield braid 16a so as substantially to abut the end of the flared skirt 42a on connector 11a so that when the connection is completed there is substantially no gap in the outer insulation provided by sheaths 18 and 19.
Figure 14 is a cross-sectional view through one of the skirt portions 42a of connector =`11a after being crimped to the shield braid 16a. support, the compression of the crimp being borne fully by the intermediate insulation 14a. In this unsupported shield connection, the triple-folded type of crimp discussed above is also Very advantageous for it causes the shield 16a to grip the intermediate insulation around substantially its entire circumference thereby giving the maximum support to the insulation 14a. This is important because some shielded wires have insulation sheaths which are subject to cold flow after being com- Connector 11a has no shield pressed and which tend to gradually ow from under the shield 16a where it is compressed against the intermediate insulation sheath by the crimped skirt portion of shield ferrule 34a, thus tending to release at least partially the binding pressure between the shield ferrule 34a and the wire shield 16a, causing a poor electrical content and lowered mechanical strength at this shield connection. Such reduced contact pressure may cause noise in electrical communication circuits. The present form of crimp minimizes this creeping of the intermediate insulation sheath, and wherever there may be any tend- 1 ency to loosen, a connector such as connector 11a with shield supporting sleeves may be used to maintain full crimping pressure between the collapsed skirt 42a of shield 34a and the shield braid 16a.
Another form of connector is illustrated in Figure 13 parts performing functions similar to Figure 12 have corresponding reference numbers with the suix 11. A shield braid support 72 is provided which fits between the intermediate insulation sheath 14b and the braided Wire or other exible metallic shielding 16b. 'Ihis support sleeve 72 is advantageously made of a hard metal, hard brass, or steel being preferred, in order to permit the shield ferrule 34b and 16b to be crimped thereaganst without undue transmission of the crimping pressures to the intermediate insulation sheath. The cylindrical sleeve 72 is disposed coaxially within the extended end of the shield ferrule 34b and held therein by an annular flange or ridge 74 which is force-fitted into the shield ferrule 34b and abutted against the end of the tubular insulation sleeve 32b. The outer transverse surface of the annular ridge 74 provides the annular abutment 38b against which the braided-wire shielding 16b is abutted during assembly of a connection. The outer end of the sleeve 72 is provided with a tapered or chamfered outer surface 78 which provides a tapered approach from theinner surface 80 to the outer surface 82, which surfaces 80 and 82 are generally cylindrical. This tapered approach advantageously projects outwardly beyond the end of the shield ferrule 34b in order to enable one making a connection assembly to work the braided-wire shield 16b over the sleeve 72 with their fingers if it does not slide up over the tapered approach easily upon insertion of the shielded wire. .Many
'shielded Wires have such dimensions and intermediate insulation sheaths of such material that they may be used for transmission lines, in which case they are often referred to as coaxial cables. As used herein the term shielded wire is intended to include any wire or cable having at least one inner conductor spaced from and at least partly surrounded by an outer conductor, often insulated therefrom by a continuous layer of insulation 14.
From the foregoing, it will be understood that the connectors, connections, method and apparatus described above are Well suited to provide the advantages set forth, can be manufactured readily by conventional fabrication techniques and that the various features and arrangements of parts may be modified to various particular shielded wire applications whereby the operator is enabled to complete good electrical and mechanical connections to shielded wire with a unitary connector. Certain features of the connectors and connections described may be used to advantage in particular applications without the use of other corresponding features and are to be considered within the scope of my invention unless specifically excluded by the following claims or required by the scope of the prior art.
' What is claimed is:
l. An electrical connector for shielded wires and the like having an inner conductor and an outer conductor shield surrounding said inner conductor and insulation therebetween, saidconnector comprising a malleable conduc- 'tive inner ferrule having a longitudinal bore adapted to receive and be crimped to an inner conductor of the shielded Wire, a relatively elongated insulation sleeve of tough, malleable, insulation material surrounding said ferrule and secured thereon and having an end portion extending beyond the end of said inner ferrule, a malleable conductive outer ferrule substantially surrounding said insulation sleeve and secured thereon and having a skirted end portion extending beyond the end portion of said insulation sleeve adapted to embrace the end of the conductor shield of the shielded wire, and a relatively rigid support for `supporting the conductor shield of the shielded wire during a crimping operation, said support having a first end of enlarged inside diameter embracing the projecting end of said insulation sleeve and extending i-nto said outer ferrule further than its skirted end portion and having a second end of reduced outside diameter having a bore aligned with the bore of said inner ferrule, ysaid second end being adapted to be inserted between the conductor shield and the insulation of the shielded wire.
2. An electrical connector for shielded wires and the like having an inner conductor and an outer conductor shield surrounding said inner conductorand insulation.-
ductive inner f errule having a longitudinal bore adapted to receive and be crimped to an inner conductor of the shielded wire, a relatively elongated insulation sleeve of tough malleable insulation material surrounding said ferrule and secured thereon and having an end portion extending beyond the end of said inner ferrule, a malleable conductive outer ferrule substantially Asurrounding said insulation sleeve and secured thereon and having a skirted end portion extending beyond the end portion of said insulation sleeveadapted to embrace the end of the conductor shield of the shielded wire, and a relatively rigid supportv for supporting the conductor shield of the shielded wire during a crimping operation, said support having a first end of enlarged inside diameter embracing the projecting end of said insulation sleeve and extending into said outer ferrule farther than its skirted end portion and having va second end of reduced outside diameter having a .a bore aligned with the bore of said inner ferrule said second end being adapted to be inserted between the conductor shield and the insulation of the shielded wire, the second end of said support being slanted to `facilitate its insertion under the conductor shield ofthe shielded wire. 3f An electrical connector for shielded wires and the like having an inner conductor and an outer conductor shield surrounding said inner conductor and insulation therebetween, said connector comprising a malleable conductive inner ferrule having a longitudinal bore adapted 'to 'receive and be crimped to an inner conductor of the shielded wire, a relatively elongated insulation sleeve of tough malleable insulation material surrounding said ferrule and'secured thereon and having an end portion extending beyond the end of said inner ferrule, a malleable conductive outer ferrule substantially surrounding said insulation sleeve and secured thereon and having a skirted end portion extending .beyond the end portion of said insulation sleeve adapted to embrace the end of the conductor shield of the shielded wire, and a relatively rigid support for supporting the conductor shield of the shielding wire during a crimping operation, said support having a first end of enlarged inside diameter embracing the projecting end of said insulation sleeve and extending into said outer ferrule farther than its skirted end portion, said outer feirule being crimped to the iirst end of said support to' 'secure it iii-mly within the outer ferrule, said support having a second end of reduced outside diameter having a bore aligned with the bore of saidr inner ferrule, said second end being adapted to be inserted between the conductor shield andthe insulation of the shielded wir'e.
il". An integral electrical connector for shielded wires and the like having an inner conductor and an outer conducto'r shield surrounding said inner conductor with insulation therebetween, said integral connector comprisingi `a malleable conductive inner ferrule adapted to receiveL and ybe crimped' to an inner conductor of the shielded wire, an insulation sleeve of tough malleable insulation materialV surrounding said innelfer'rule and beingsec'ured thereon, said insulation sleeve having an enti' portion extending beyond the end of said ferrule with an annular recess around its projecting end, a malleable conductive outer fertule substantially surroundsid insulation sleeve and being secured thereon and having an end portion extending beyond the end por- 'tion of said insulation sleeve, and a relatively rigid supporting' sleeve 'for supporting the conductor shield of the' shielded wirel during a crimping operation, said supporting sleeve having a` rst end of enlarger inside diameter engaging in said' annular recess and having a see-y o'n'dl end of' reduced outside diameter adapted to be inserted' between thev conductor shield and the insulation or theshieldeii wire, an 'external abutment en said supporting sleeve intermediate its ends, said outer ferrule Being 'crinped into engagement with said supporting Steeve-adjacent Said abutment.
'5'. A connector as' claimed in cl'ni 4` and wherein th external abutment on said supporting sleeve comprises an annular shoulder forming a transition region between its first and second ends.
6. An integral electrical connector for shielded wires and the like having an inner conductor and an outer.
conductor shield surrounding said inner conductor with insulation therebetween, said integral connector comprising amalleable conductive inner ferrule adapted to receive and be crimped to an inner conductor of the shielded wire, an insulation sleeve of tough malleable insulation material surrounding said inner ferruleand secured thereon, said insulation sleeve having an end portion extending beyond the end of said ferrule, a malleable conductive outer ferrule substantially surrounding said insulation sleeve and secured thereon, and
having a full skirted end adapted to receive the conductor shield of the'wire, and a relatively rigidsupporting sleeve for supporting the conductor shield of the shielded wire during a crimping operation, said supporting sleeve having a first en dof enlarged insidediameter embracing the end portion of said insulation sleeve and a second end of reduced outside diameter adapted to be inserted between the conductor shield and the insulation of the shielded wire, said full skirted end extending b eyond the end portion of said insulation sleeve and also beyond the second end of said supporting sleeve, whereby to embrace and support the conductor shield of the shielded wire when crimped thereto. I l
7. An integral electrical connector for shielded wires and the like comprised of a malleable conductive inner ferrule having two electrically connected ferrule portions in end-to-end spaced relationship with an opening therebetween, said ferrule portions having longitudinal bores each adapted to receive and be crimped to the inner conductor of a shielded wire, a relatively elongated sleeve .of tough malleable transparent insulation material surrounding said inner ferrule and extending a distance beyond the extreme ends thereof, and a malleable conductive outer ferrule surrounding said transparent sleeve and extending a distance beyond the ends thereof and being flared outwardly at the ends thereof7 at Vleastjon its inner surface, to form a wire-shield-engaging portion for engaging the shielding ofv a shielded wire,V said outer ferrule having a central window therein adjacent the opening in said inner ferrule, said transparent sleeve being depressed transverselyin the area of said window at least partially into said opening, whereby said depressed region of the sleeve forms a pane in said window closely adjacent the bores of said inner ferrule portions.
8. An integral connector as claimed in claim 7 and wherein said sleeve as seen in cross section in the region ofysaid window has a generally semicircular.appearance.
9. Anintegral electrical connector for shielded wires and the like comprised of a malleable conductive inner ferrule having two electrically connected` ferrule portions in end-to-end spaced relationship with an opening therebetween, said ferrule portions having longitudinal bores each adapted to receive and be crimped to the inner conductor of a shielded wire, a relatively elongated sleeve of tough malleable transparent insulation material surrounding said inner ferrule andextendinga distance beyond the extreme ends thereof, a malleable conductive outer ferrule surrounding said transparent sleeve Yand ex'- tending a distance beyond the ends thereof and being flared outwardly at the ends thereof, at least onits inner surface, to form a wire-shield-engaging portion for engaging the shielding of a shielded wire, said outer ferrule having a central approximately rectangular window therein adjacent the opening in said inner ferrule, said transparent sleeve being depressed transversely in the area of said window at least partially into said opening, to form a pane in said window closely adjacent the -inner ends of the bores of said inner ferrule portions, theA opposite edges of said outer ferrule extending parallel to the axis ofr said connector in the region of the l 13 window being rolled over onto the adjacent edges of the pane portion of said sleeve.
10. An integral electrical connector for shielded Wires and the like comprised of a malleable conductive inner ferrule having two electrically connected ferrule portions in end-toend spaced relationship with an opening therebetween, said ferrule portions having longitudinal bores each adapted to receive and be crimped to the inner conductor of a shielded wire, a relatively elongated sleeve of tough malleable transparent insulation material fitting around said ferrule portions and having open ends extending beyond the extreme ends of said ferrule portions, and a malleable conductive outer ferrule surround-F ing said transparent sleeve and extending a distance beyond the ends thereof and being flared outwardly at the ends thereof, at least on its inner surface, to form a wireshield-engaging portion for engaging the conductor shield of a shielded wire, said outer ferrule having a central window therein adjacent the opening in said inner ferrule, said transparent sleeve being depressed in the area of said window into said opening to form a pane in said window closely adjacent the inner ends of the bores of said inner ferrule portions, and a pair of supporting sleeves, each having a rst end between the outer surface of an end of said transparent sleeve and said outer outer ferrule and each having a second end projecting outwardly coaxially with an open end of said transparent sleeve, said outer ferrule being crimped into engagement with the inner end of each of said supporting sleeves by a pair of opposed approximately semi-circular crirnps.
ll. An integral electrical connector for shielded Wires and the like comprised of a malleable conductive inner ferrule having two electrically connected ferrule portions in end-to-end spaced relationship with an opening therebetween, said ferrule portions having longitudinal bores each adapted to receive and be crimped to the inner conductor of a shielded wire, a relatively elongated sleeve of tough malleable transparent insulation material tting around said ferrule portions and having open ends extending a distance beyond the extreme ends of said ferrule portions, a malleable conductive outer ferrule surrounding said transparent sleeve and extending a distance beyond the ends thereof and being flared outwardly at the ends thereof, at least on its inner surface, to form a wire-shieldengaging portion for engaging the conductor shield of a shielded wire, said outer ferrule having a central approximately rectangular window therein adjacent the opening in said inner ferrule, said transparent sleeve being depressed in the area of said window into said opening to form a pane in said window closely adjacent the inner ends of the bores of said inner ferinle portions, the longitudinal edges of said outer ferrule adjacent said window being rolled over onto the adjacent edges of the pane portion of said sleeve, and a pair of supporting sleeves for supporting the conductive shields of the shielded wires during a crimping operation, each of said supporting sleeves having an inner end of enlarged diameter surrounding the extending end of said insulation sleeve and having an outer end of reduced diameter adapted to be inserted between the conductor shield and the insulation of a shielded wire, the outer end of said shield supporting ferrule being cut off at an angle to form an elliptical opening to facilitate insertion under a conductor shield of a wire.
l2. A connector as claimed in claim ll and wherein the elliptical opening on the ends of said supporting sleeves face in substantially the same direction as said window.
13. An electrical connector for shielded wires and the like comprised of a malleable metal central conductor fermle having a cylindriform bore, said bore being outwardly flared at the extreme ends thereof to form funneled entrances thereto, a relatively elongated tubular sleeve of very tough, rigid and substantially malleable insulation material surrounding said ferrule and extending a distance beyond the extreme ends thereof, and a shield ferrule of malleable metal surrounding said tubular sleeve and extending a distance beyond the end thereof to form wire-shield-engaging portions, said shield ferrule being flared outwardly at the ends thereof, at least on its inner surface, to form funneled entrances to said wireshield-engaging portions and means at each end of the shield ferrule for preventing the central ferrule from contacting the shielding on the wires.
14. An electrical connector for shielded wires and the like comprised of a malleable metal central conductor ferrule, a relatively elongated tubular sleeve of very tough, rigid and substantially malleable insulation material surrounding said ferrule and extending a distance beyond at least one end thereof, a shield ferrule of malleable metal substantially surrounding said tubular sleeve and extending a distance beyond the extended end thereof to form a wire-shieldnengaging portion, and a generally cylindriform shield support disposed coaxially within said wire-shield-engaging portion, said shield support having a cylindriform bore and an outer, generally cylindriform, surface contiguous with the inner surface of the shield ferrule, said outer surface being tapered toward said bore at the extreme outer end of said shield support so that the tapered portion of the shield support and the inner surface of the shielding ferrule form a space to receive the shielding on the wires, and said shield support having an annular ridge adjacent the extended end of said tubular sleeve, said ridge extending from said outer surface to said shield ferrule, said annular ridge presenting a transverse annular abutment between said outer surface of said shield support and the inner surface of said shield ferrule.
l5. An electrical connector for shielded wires having an inner conductor, an outer conductive braid, and an insulation layer therebetween, comprising an inner malleable metal ferrule, a relatively elongated sleeve of tough malleable plastic surrounding said ferrule and extending a distance beyond the end of said inner ferrule, and a tubular braid-support having a first free end extending beyond the end of said insulation sleeve, an outer malleable metal sheath surrounding said sleeve and extending a substantial distance beyond the end of braid support, said sheath being flared outwardly at its extending end with the edge of the end of said sheath being curled back over itself to form a double thickness bead.
16. An electrical connector for shielded wires having an inner conductor, an outer conductive braid, and an insulation layer therebetween comprising an inner malleable metal ferrule, a relatively elongated sleeve of tough malleable plastic surrounding said ferrule and extending a distance beyond the end of said inner ferrule, and a tubular braid-support having a rst free end extending beyond the end of said insulation sleeve and cut off at an angle in the range from 45 to 75 with respect to the connector axis, an outer malleable metal sheath surrounding said sleeve and extending a distance beyond the end of said braid support, said sheath being flared outwardly at its extending end with the end of said sheath being curled inwardly tight against itself to form a double thickness bead, said bead being positioned entirely beyond the iirst free end of said braid support.
17. An electrical connection to the end of a shielded wire having an inner conductor, a conductive shield therearound, and an insulation layer therebetween comprising an inner ferrule crimped to the bared end of said inner conductor, an insulation sleeve surrounding said inner ferrule and having an end overlying the adjacent end of said insulation layer, a tubular shield support having a rst end around said insulation layer beneath said shield and a second end overlying said end of the insulation sleeve, and an outer ferrule overlying said insulation sleeve, said shield support and said shield, said outer ferrule projecting over said shield beyond the first end of said shield support, said outer ferrule being crimpedrmly down against areas or" said shield over the' iirst end of said shield support and the projecting portion of said outer ferrule being crimped down rmly against said shield near the first end of said shield support.
18. A' solderless crimped electrical connection between an electrical connector and a shielded wire having an inner conductor and an outer conductor surrounding said inner conductor in substantially concentric relationship therewith and insulation means supporting said outer conductor in insulated spaced relationship around said inner conductor, said connector including an inner malleable tubular metal ferrule, an outer malleable tubular metal ferrule having its end projecting a distance beyond the end ofv the inner ferrule, and tough rigid substantially malleable insulation material surrounding said inner ferrule and supporting said outer ferrule in concentric relationship therewith, said inner, ferrule, insulation material and outer ferrule forming an integral connector unit, said insulation material including a portion continuing beyond the end of the inner ferrule and terminating inside of the outer ferrule at a position longitudinally between the end of the inner ferrule and the end of the outer ferrule, said inner ferrule surrounding a bare end portion of the inner conductor of the shielded wire and being deformed into intimate engagement With the inner conductor by deformation of the outer ferrule and of the insulation material, said outer ferrule surrounding an endportion ofthe outer conductor andbeingdeformed into intimate engagement with the outer con'- ductor', the portion of the insulation material beyond the end of'the inner ferrule providing insulation spacing preventing tlie entry of the outer conductor into the outer ferrule beyond said insulation spacing and holding said outer conductor longitudinally offset from the end of the inner conductor, thereby assuring that said outer conductor'renrains spaced away from conductive engagement with the'inner ferrule so as to prevent a'short circuit betweeny the inner and outer conductors.
References Cited in the file of this patent UNITED STATES PATENTS R'e. 23,688' Watts `Tuly 21, 1953 477,951 Mezger June 28, 1892 2,018,996 Christians Oct, 29, 1935 2,182,663 Eby et al. Dec'. 5, 1939 2,291,051 Mascuch July 28, 1942 2,429,585' Regen oct. 21, 1947 2,478,082 Broske Aug. 2, 1.949 2,536,003 Dupre Dec. 26, 1950 2,729,695 Pierce Jan.y 3, `1956 Y FOREIGN PATENTS 102,137 Great Britain Nov. 13, 1916