CA1196403A - Connector for use with jacketed metal clad cable - Google Patents
Connector for use with jacketed metal clad cableInfo
- Publication number
- CA1196403A CA1196403A CA000442172A CA442172A CA1196403A CA 1196403 A CA1196403 A CA 1196403A CA 000442172 A CA000442172 A CA 000442172A CA 442172 A CA442172 A CA 442172A CA 1196403 A CA1196403 A CA 1196403A
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- Canada
- Prior art keywords
- cable
- connector
- diameter
- fingers
- metal clad
- Prior art date
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Abstract
UNITED STATES PATENT AND TRADEMARK OFFICE
Title: Connector For Use with Jacketed Metal Clad Cable Inventors:Jay J. Bolante and Herbert W. Penzel A connector for connecting jacketed, metal clad cable to an electrical box includes a tubular metallic body with a stamped and formed retainer element preferably staked therein. This retainer element has an annular rim with radially inwardly directed fingers formed or bent toward the electrical-box end of the connector for permitt-ing insertion of the cable therein preparatory to affixing the two together, for preventing withdrawal of that cable in the opposite direction, and also for providing an electrical grounding continuity. The connector also features an elasto-meric compression grommet that compresses into the cable jacket upon the tightening of a nut onto the connector body.
A Teflon washer between grommet and nut minimizes the fric-tional resistance therebetween as the nut is tightened onto the connector body.
Title: Connector For Use with Jacketed Metal Clad Cable Inventors:Jay J. Bolante and Herbert W. Penzel A connector for connecting jacketed, metal clad cable to an electrical box includes a tubular metallic body with a stamped and formed retainer element preferably staked therein. This retainer element has an annular rim with radially inwardly directed fingers formed or bent toward the electrical-box end of the connector for permitt-ing insertion of the cable therein preparatory to affixing the two together, for preventing withdrawal of that cable in the opposite direction, and also for providing an electrical grounding continuity. The connector also features an elasto-meric compression grommet that compresses into the cable jacket upon the tightening of a nut onto the connector body.
A Teflon washer between grommet and nut minimizes the fric-tional resistance therebetween as the nut is tightened onto the connector body.
Description
1~6~03 BACKGROUND AND SU~ARY OF l'HE INVENTION
_ _ _ _ _ _ _ One relatively new type of electrical. cab~e now gaining increasing popularity and acceptance comprises a flexible metallic tube entirely covered with a layer of plastic or other elastorneric material. Some manufacturers of thcse cables fabricate the tublllar metallic core from helical windings making it similar to "BX" cable, whil.e others flute a metallic tube annularly along its ler,qth similar to the manner of forming hydroformed bellows. 'l'hese con-]0 figurations provide the cable with a dcgree ,f flexibility.
At least several connectors have appeared on the marketwhich are designed specifically for connecting this type of cable to an electrical box. Each of these includes at least one compromise somewhere in its design that either unduly i.ncreases its cost, limits its use to a narrow range of cable si~e, or requires an unnecessarily ]ong installa-tion ti~le.
: : An effective connector for this type of cable should preferrably be capahle of assembly quickly and easily both to the cable and to an electrical box, accomodat.e a relative-ly wide range of cable sizes, provide a solid electrical yrounding connect.ion between the metal portions of the cable and the electrical box, and in some applications provide a reasonable seal between the inside of the hox and the o~tside cllv;.ronmenta ~' 1;~
.
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`' -'` ' 13 9~403 .
The present invention is used in a connec-tor assembly for connecting metal clad cable to an electrical box, the connector assembly including a generally tubular body defining an outer end, an inner end, a larger and smaller inner diameter, and also including a stamped retaining element having an annular rim portion. The invention relates to the improvement comprising: the retaining element having an outer diameter stamped to very nearly the same dimension as the larger inner diameter and having a plurality of narrow and relatively widely spaced fingers extending radially in-wardly from the annular rim portion and numbering at least five, each finger beinq several. times longer than its width, the fingers being canted away from the outer end of the assembly and cumulatively terminating radially inwardly in interfering relationship relative to the diameter of the metal clad cable whereupon the metal clad cable will significantly deflect the fingers when pushed therethrough inwardly but the radially innermost portions of the fingers dig into the cable so that it cannot be withdrawn thereafter, the tubular body having one internal diameter very nearly the same dimension as the outer diameter of the retaining element, and a shoulder adjacent the diameter for locating the retainer ring at a specific longitudinal position within the tubular body after it is assembled therein.
. T~ie connector embodying this invention (which will be described in greater detail later) includes a tubular connector body and a connector nut, both of which are e~ternal and visible parts, and internally it includes a retainer element, a rubber bushing and an anti-friction washer. The - 2a -~6~)3 retainer elemen-t hast~eshape of a thin, narrow-rim washer with a plurality of integrally formed fingers or prongs extending radially inwardly which are formed or bent some-what toward the electrical box end of the connector. E.ach of these fingers terminates short of the center of the washer so that, cumulatively, they form a central opening which is deliberately smaller than the diameter of the metallic por-tions of the cable. Before the cable is attached to the connector, the outer plastic coating is stripped from its end to expose these metallic portions for direct attach-ment of the connector thereto. Because different manufacturers - produce what is supposed to be standard size cable, but which in fact has metallic portions with significantly different diameters and tolerances, these fingers in the connector assembly must be properly designed to permit a given size cable from any manufacturer to pass through the center hole of the retainer element and deflect the fingers thereon when the cable is moving therethrough in the direction of the electrical box. But, because these fingers are bent ~0 toward the elect:rical box to begin with, any attempt to pull the cable in theopposite direction away from the electrical box causes the fingers to dig or bite into the cable and prevent its removal. Although the retaining ; element is preferrably staked or swaged in place within the tubular connector body so as to always be fixed and properly oriented for use, it would also work if not affixed to the connector body, although perhaps not with a comparible grounding inte~rity.
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,96403 The ease and simplicity of attaching the cable to the connector is further enhanced by appropriately si~ing the parts such that the entire connector assembly can be shipped in assembled form with the conneetor nut drawn up on the connector body by hand. As will be seen, a further tighten-ing of this conneetor nut (as with a wreneh) eauses a radial contraction of the rubber grommet to produee an inner diameter which would interfere with the free entry therethrough of the cable. Thus, since the connector nut is not drawn up tightly when shipped, the installer of the connector nePd only properly prepare the end oE the cable (in accordance with directions supplied) and push it through the connector to lock the connector and the cable together. Then, simply by tighten-ing down on the conneetor nut with an appropriate tool, the conneetor is further locked onto the cable-and an effective sealed conneetion has also been made.
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Because of the importance of creating a good electrical ground between the cable and the electrieal box, a proper preparation of the end of the cable requires stripping a designated length of the plastic jacket from the end of the cable. Thus, the retainer element's fingers in fact bite into the metallic portions of the cable so as to electrically connect them. To ensure there exists a ground between tho retainer ring and the retainer body, the retainer ring fingers, ; when angularly deflected by the cable, eause ti,e annular rim portion of the retainer ring to eontort and bite into the eonnector body. Thus, two,grolmding effeets occur simultane-ously with the Illere pushing of the cable into the connector 1~9 6 ~ 3 body. ~lectrical continuity bet-;cen the connector body and the electrical bo~ is conventionally acllievcd by the locknut that holds the connector in place in the clectrical bo~.
One other effect worth mention takes place during final tightening of the connector nut. Because the gromrnet is comp~essed into the cable during final tigllt(-ning, the last Eew turns of the nut drive the cable further inwardly such that its metallic portions rigidly compress against an internal tapered surface. This both prov;des additional lateral stability for the conrlect;on as wcll as provides supplernental ground continuity.
Thus, an installer need only strip the end of the cable, push the cable through the connector until it abuts the internal tapered surface, and tighten down tilr-~ nut to complete both a solid mechanical and reliable electrical ground connection between cable and connector assembly.
119~i~03 DE:SCRIPTION OF 'J')!E DI~ II`l(;S
Figllre 1 is a longitu(]inal cross-sectional view of a connec~or assembly embodying the elemonts o~ the present invrntion this view including a segment of jacketed metal clad rable sccured therein so as to ~how the rela-tionship between the connector and a cable connected thereby.
Figure 2 is an exploded perspective view of the connector shown in Figure 1.
Figure 3 is a cross-sectional view of the connector body subassembly with the retainer element in place and locked therein.
Figure 4 is an end view of the retaine~ el~ment showing : the relative size and configuration of the outer annular rim portion and the individual fingers.
: Figure 5 is a cross-sectional view of the connector with a sliyhtly modified body portion for explosionproof applica-tions.
I)E:_CRIPrI_N OF PRhYERRED EMBODIM~NT
Referri~ng now to Figures 1 thru 4, and particularly to Figure 1 initially, I:here lis shown a connector assembly 10 including a connector body 12, a retainer elru!lent 14 a connector nut 16, a grorrrmet 18 and a washer 20. Connecl:or assembly 10 is used to connect a longth of metal clad cable , -- 6 -- . ...
:
64()3 shown generally at 30 to an elcctrical box (not shown) in a conventional manner. Cable 30 includes a rluted mctall;c portion 32 that protectively covers and shie1ds a plurality of conductors 34, 35 and 36. ~lctallic portions 32 of the cable are coated or covered with a siynificaot 1ayer of plastic or other e1asLomcric matrrial 38.
Referring I~OW to connector body 12, it is generally tubular in shape with a large external thread 40 at its outermost end, a smaller external thread 42 at its innermost or electrical box end, and a portion 44 there-between having a generally hexagonally shaped outer con-figuration which can be grasped by a wrench or equivalent tool. Internally the connector body l2 has four concentric diameters which get progressively smaller from the outer end to the inner, electrical-box end. The largest diameter internal surface 50 is at the outer end inside threads 40, and it steps down to a slightly smaller diameter surface 52 which is guite short axially and which ends at an outwardly facing sl1oulder 54. From shoulder 54 tl1e inner surface of the connector body slopes to a smaller diameter surface 56 that is pref~rrably larger then the dia-meter of the me~allic portions 32 o~ cable 30. Diameter 56 then slopes along surface 57 down to the smallest dia-meter surface 58 which dcliberately has a smaller diameter than the metallic por~ion 32 of cable 30 so that it cannot pass therethrough. 11owever, this smallest diameter internal surface 58 is sufricicntly 1~arge to pe~mit all of the cablcs 34-36 to pass therebe1:ween and into the interior of an electrical box.
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~196~()3 Referring now specifically to F;gure 3 there is shown the connector body 12 with retainer element 14 locked in place.
Although reLainer e~ement 14 co~lld he carried looscly ins;de surface 52, preferrably it is eithcr pressed into that surface by way oE an interferance fit or, as shown here, it is loo.scly set against shoulder 54 and staked in place. T}lus, as shown in the drawings, the outer dian,eter of retainer element 14 is slightly smaller than the diameLer of surface 52, and a swaging tool (not shown) having portions larger in diameter than the dialneter of surface 52 and smallcr than the diameter of surace 50 is used to upset portions 59 of surface 52 and drive them against retainer element 14 to lock it against shoulder 54. No more manufacturing operations are needed with this staking operation than would be needed by interferingly pressing the element in place, however ovèrall manufacturing cost is less because tolerances both for internal diameter 52 and for the outside diameter of the retainer element 14 are not as critical as they are with a pres~: fit.
Retainer element 14 is preferrably formed either from spring temper sheet metal or it is later he~t treated, and it has a thin outer rim or annulus 60 (see ~igure 4) with a plurality of at least five radially inwardly project-ing fingers or prongs 62, here being shown specifically as eight in number. Fingers 62 are each about three times as long as they are wide, and they are bent away from the plane of annulus 60 toward the inner end of the connector at an angle o approximately 35,, although satisracto-y rcsulLs could be achieved with angles up to about 55. The distal ends of all of the fingers 62 terminate on thc circumference of an imaginary circle which is smaller in diameter then the .
964()3 smallest possible diameter of the metallic portions 32 of a givcn nominal si~e of cable 70.
Conrlector nut 16 has a generally hexagonal ruter configu-ration and an internal thread 64 therein. The outermost end 66 of c~nnector nut ]6 is turncd radially ;nwardly to form a flancJe and define both the nuts mini~llurn diameter surface 67 and an inwardly facing shoulder 68.
Grommet 18i is of generally tubular shape and is molded of rubber or some other desirable clastomer. Referring 10 specifically to Figure 2 it includes an outermost end surface 70, ?najor and minor outer diameters 71 and 72 (respectively) joined by an intermediaLy tapered surface 74, and also an innermost end surface 75. An axial hole 76 extends therethrough which is of a free or undeiormed diameter slightly greater than the outer.diameter of the plastic covering 38 of the largest cable 30 intended to be used with the connector. Minor ou'er diameter 72 fits loosel~y inside surface 50 of the connector body, and tapered surface 74 abuts a chamfer 78 at the outermost 20 edge of the _onnector body when originally assclllbled and prior to thc- final tiyhtening of the connector nut that clamps the cable in place.
: Washer 20 comprises anti-friction means, is preferrably constructecl of some low friction material such as Teflon has an outer d;ameter slig1~tly lar~3er than the ouLer diamcter of grolr~net :L8, and it's inller diameter is sliglltly lasger than the inner d;ameter of grommet 18. Dur;ng assembly of the entire c~ollllector a.ssemhly, w.lsher 20 :s positionecl be-tween .shoulder 68 on the connector nut and qromnlet surface 71.
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~64(~3 As alluded to earlier, the conllector body subassemhly is ass-~mbled by first dropping retainer e]ement 14 lnto the outer end of conllector body 12 such that it lies against shoulder 54 with its fingers 62 slanting inwardly toward the clectrical bo~ end of t],e connector body. Prc-ferrably th(n a stakiT2g tool is drivcn i~to the outer end of the connestor body 12 to upset sollle of the ~laterial forming inncr surface 52 and thereby Eix retainer element 14 in that position. Compression grommet 18 and anti-friction washer 20 are dropped into connector nllt 16, andthen connector nut 16 is screwed up on threads 40 by hand until resistance is felt. The connector assembly is then shipped in this condition.
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Jn use, the user has the option of first^attaching the connector a~sembly e.ther to an electrical box or to the cable. In either event, a final assembly.invo]ves strip-ping a designated length of the outer plastic coating 3B
from cable ?0 so as to expose a proper length of metallic portions 32, pushing this prepared end of cable 30 into the outer end of connector assembly 10 untiL the exposed edge of metallic portions 32 abuts internal surface 57 inside the connector body, and then tighten;.ng nut 16 until a11 threads are taken up and its leading edge abuts the conncctor body. .~s nut 16 rotates, it moves compression gro~mnet 18 toward the inner end of the conncctor causing it to be compressed radially inwardly c.o as to squee~e the plastic jacket 38 of the cable to both hold the cable 30 and seal it relative to the connector assembly. During the last fcw turns of nut 36, after compression grollunet 18 , ~lg~03 is already firmly in contact with jacket 38, cnb~e 30 is even f~-rther p~lshcd into the connec~or tow~td its elcctr;cal box end. Anti-friction washer 20 a:-oids direct contact between the driving surface 68 of the connector nut and the outer surface 71 of the compression grommet l8. This minimiZe9 resistive torque on the nut and permits the gromrnet 18 and cable 30 to move axially to the right without twisting.
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Figure 5 shows a connector assembly designated generally 80 having a modified connector body 82 for use in conjunation with explosionproof applications where explosiollproof scals are required. ln the arrangement shown, the inner threaded end 83 of connector assembly 80 is screwed into a standard pottincl fitting 84. Potting fitting 84 has various side openings for introducing sealing material-therein (as is well known in the art), and it is conventionally located between assemoly 80 and some form of electrical box 86 or the like. Retainer element 14, connector nut 16, compression grommet 18 and anti-friction washer 20 are identical with the elements shown in Figures 1-4 and thus carry the same identifi-cation numbr,rs. ~he principal dif-erence lies in the connec-; tor body 82, and it will be noted that the inner end of that body illcludcs a relatively lar(;e e~ternal thrcad 85 which permits a l~rge diameter internal hole 86 to extend thro~lgh that end oE the conllector, its diameter being larger than :
that of the metallic portions of cable 30.
It will also be noted t~lat the netallic porli--ns 32 oE
::: :
cable 30 have been stripped of their plastic jacket 38 over a longer sp~n than in the earlier embodiment which permits ::
~ ~ a long r scgment of cable to be pushed tt~ongt, the connector ;~ ~ ~//~ ,, ~: , ~:
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assembl~ 80. This is desirable so that the stripped cnd of metallic port;(-ns 32 locate insi(1e pol:ting f;tting 84 so that thcy can he properly and thorougllly sealr-d with potting compound according to well known practLce.
Although the forcgoi.nq disclosure is detailed to ensure adequacy and aid ullderstandi.ng this is not intended to prejudice that purpose of a patent .~hich is to cover each new inventive concept therein no matter hGw others may later disguise it oy variations in form or additions or further improvements. The follo~cing claims are i:tended as the chief aid towards this purpose, as it is these that meet the reguirements of pointing out the parts, improvements or combinat~-~ns in which the inveDtlve c^ncepLs are ~ound.
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_ _ _ _ _ _ _ One relatively new type of electrical. cab~e now gaining increasing popularity and acceptance comprises a flexible metallic tube entirely covered with a layer of plastic or other elastorneric material. Some manufacturers of thcse cables fabricate the tublllar metallic core from helical windings making it similar to "BX" cable, whil.e others flute a metallic tube annularly along its ler,qth similar to the manner of forming hydroformed bellows. 'l'hese con-]0 figurations provide the cable with a dcgree ,f flexibility.
At least several connectors have appeared on the marketwhich are designed specifically for connecting this type of cable to an electrical box. Each of these includes at least one compromise somewhere in its design that either unduly i.ncreases its cost, limits its use to a narrow range of cable si~e, or requires an unnecessarily ]ong installa-tion ti~le.
: : An effective connector for this type of cable should preferrably be capahle of assembly quickly and easily both to the cable and to an electrical box, accomodat.e a relative-ly wide range of cable sizes, provide a solid electrical yrounding connect.ion between the metal portions of the cable and the electrical box, and in some applications provide a reasonable seal between the inside of the hox and the o~tside cllv;.ronmenta ~' 1;~
.
,' ~
.
`' -'` ' 13 9~403 .
The present invention is used in a connec-tor assembly for connecting metal clad cable to an electrical box, the connector assembly including a generally tubular body defining an outer end, an inner end, a larger and smaller inner diameter, and also including a stamped retaining element having an annular rim portion. The invention relates to the improvement comprising: the retaining element having an outer diameter stamped to very nearly the same dimension as the larger inner diameter and having a plurality of narrow and relatively widely spaced fingers extending radially in-wardly from the annular rim portion and numbering at least five, each finger beinq several. times longer than its width, the fingers being canted away from the outer end of the assembly and cumulatively terminating radially inwardly in interfering relationship relative to the diameter of the metal clad cable whereupon the metal clad cable will significantly deflect the fingers when pushed therethrough inwardly but the radially innermost portions of the fingers dig into the cable so that it cannot be withdrawn thereafter, the tubular body having one internal diameter very nearly the same dimension as the outer diameter of the retaining element, and a shoulder adjacent the diameter for locating the retainer ring at a specific longitudinal position within the tubular body after it is assembled therein.
. T~ie connector embodying this invention (which will be described in greater detail later) includes a tubular connector body and a connector nut, both of which are e~ternal and visible parts, and internally it includes a retainer element, a rubber bushing and an anti-friction washer. The - 2a -~6~)3 retainer elemen-t hast~eshape of a thin, narrow-rim washer with a plurality of integrally formed fingers or prongs extending radially inwardly which are formed or bent some-what toward the electrical box end of the connector. E.ach of these fingers terminates short of the center of the washer so that, cumulatively, they form a central opening which is deliberately smaller than the diameter of the metallic por-tions of the cable. Before the cable is attached to the connector, the outer plastic coating is stripped from its end to expose these metallic portions for direct attach-ment of the connector thereto. Because different manufacturers - produce what is supposed to be standard size cable, but which in fact has metallic portions with significantly different diameters and tolerances, these fingers in the connector assembly must be properly designed to permit a given size cable from any manufacturer to pass through the center hole of the retainer element and deflect the fingers thereon when the cable is moving therethrough in the direction of the electrical box. But, because these fingers are bent ~0 toward the elect:rical box to begin with, any attempt to pull the cable in theopposite direction away from the electrical box causes the fingers to dig or bite into the cable and prevent its removal. Although the retaining ; element is preferrably staked or swaged in place within the tubular connector body so as to always be fixed and properly oriented for use, it would also work if not affixed to the connector body, although perhaps not with a comparible grounding inte~rity.
.~ .
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.... .
,96403 The ease and simplicity of attaching the cable to the connector is further enhanced by appropriately si~ing the parts such that the entire connector assembly can be shipped in assembled form with the conneetor nut drawn up on the connector body by hand. As will be seen, a further tighten-ing of this conneetor nut (as with a wreneh) eauses a radial contraction of the rubber grommet to produee an inner diameter which would interfere with the free entry therethrough of the cable. Thus, since the connector nut is not drawn up tightly when shipped, the installer of the connector nePd only properly prepare the end oE the cable (in accordance with directions supplied) and push it through the connector to lock the connector and the cable together. Then, simply by tighten-ing down on the conneetor nut with an appropriate tool, the conneetor is further locked onto the cable-and an effective sealed conneetion has also been made.
.
Because of the importance of creating a good electrical ground between the cable and the electrieal box, a proper preparation of the end of the cable requires stripping a designated length of the plastic jacket from the end of the cable. Thus, the retainer element's fingers in fact bite into the metallic portions of the cable so as to electrically connect them. To ensure there exists a ground between tho retainer ring and the retainer body, the retainer ring fingers, ; when angularly deflected by the cable, eause ti,e annular rim portion of the retainer ring to eontort and bite into the eonnector body. Thus, two,grolmding effeets occur simultane-ously with the Illere pushing of the cable into the connector 1~9 6 ~ 3 body. ~lectrical continuity bet-;cen the connector body and the electrical bo~ is conventionally acllievcd by the locknut that holds the connector in place in the clectrical bo~.
One other effect worth mention takes place during final tightening of the connector nut. Because the gromrnet is comp~essed into the cable during final tigllt(-ning, the last Eew turns of the nut drive the cable further inwardly such that its metallic portions rigidly compress against an internal tapered surface. This both prov;des additional lateral stability for the conrlect;on as wcll as provides supplernental ground continuity.
Thus, an installer need only strip the end of the cable, push the cable through the connector until it abuts the internal tapered surface, and tighten down tilr-~ nut to complete both a solid mechanical and reliable electrical ground connection between cable and connector assembly.
119~i~03 DE:SCRIPTION OF 'J')!E DI~ II`l(;S
Figllre 1 is a longitu(]inal cross-sectional view of a connec~or assembly embodying the elemonts o~ the present invrntion this view including a segment of jacketed metal clad rable sccured therein so as to ~how the rela-tionship between the connector and a cable connected thereby.
Figure 2 is an exploded perspective view of the connector shown in Figure 1.
Figure 3 is a cross-sectional view of the connector body subassembly with the retainer element in place and locked therein.
Figure 4 is an end view of the retaine~ el~ment showing : the relative size and configuration of the outer annular rim portion and the individual fingers.
: Figure 5 is a cross-sectional view of the connector with a sliyhtly modified body portion for explosionproof applica-tions.
I)E:_CRIPrI_N OF PRhYERRED EMBODIM~NT
Referri~ng now to Figures 1 thru 4, and particularly to Figure 1 initially, I:here lis shown a connector assembly 10 including a connector body 12, a retainer elru!lent 14 a connector nut 16, a grorrrmet 18 and a washer 20. Connecl:or assembly 10 is used to connect a longth of metal clad cable , -- 6 -- . ...
:
64()3 shown generally at 30 to an elcctrical box (not shown) in a conventional manner. Cable 30 includes a rluted mctall;c portion 32 that protectively covers and shie1ds a plurality of conductors 34, 35 and 36. ~lctallic portions 32 of the cable are coated or covered with a siynificaot 1ayer of plastic or other e1asLomcric matrrial 38.
Referring I~OW to connector body 12, it is generally tubular in shape with a large external thread 40 at its outermost end, a smaller external thread 42 at its innermost or electrical box end, and a portion 44 there-between having a generally hexagonally shaped outer con-figuration which can be grasped by a wrench or equivalent tool. Internally the connector body l2 has four concentric diameters which get progressively smaller from the outer end to the inner, electrical-box end. The largest diameter internal surface 50 is at the outer end inside threads 40, and it steps down to a slightly smaller diameter surface 52 which is guite short axially and which ends at an outwardly facing sl1oulder 54. From shoulder 54 tl1e inner surface of the connector body slopes to a smaller diameter surface 56 that is pref~rrably larger then the dia-meter of the me~allic portions 32 o~ cable 30. Diameter 56 then slopes along surface 57 down to the smallest dia-meter surface 58 which dcliberately has a smaller diameter than the metallic por~ion 32 of cable 30 so that it cannot pass therethrough. 11owever, this smallest diameter internal surface 58 is sufricicntly 1~arge to pe~mit all of the cablcs 34-36 to pass therebe1:ween and into the interior of an electrical box.
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~196~()3 Referring now specifically to F;gure 3 there is shown the connector body 12 with retainer element 14 locked in place.
Although reLainer e~ement 14 co~lld he carried looscly ins;de surface 52, preferrably it is eithcr pressed into that surface by way oE an interferance fit or, as shown here, it is loo.scly set against shoulder 54 and staked in place. T}lus, as shown in the drawings, the outer dian,eter of retainer element 14 is slightly smaller than the diameLer of surface 52, and a swaging tool (not shown) having portions larger in diameter than the dialneter of surface 52 and smallcr than the diameter of surace 50 is used to upset portions 59 of surface 52 and drive them against retainer element 14 to lock it against shoulder 54. No more manufacturing operations are needed with this staking operation than would be needed by interferingly pressing the element in place, however ovèrall manufacturing cost is less because tolerances both for internal diameter 52 and for the outside diameter of the retainer element 14 are not as critical as they are with a pres~: fit.
Retainer element 14 is preferrably formed either from spring temper sheet metal or it is later he~t treated, and it has a thin outer rim or annulus 60 (see ~igure 4) with a plurality of at least five radially inwardly project-ing fingers or prongs 62, here being shown specifically as eight in number. Fingers 62 are each about three times as long as they are wide, and they are bent away from the plane of annulus 60 toward the inner end of the connector at an angle o approximately 35,, although satisracto-y rcsulLs could be achieved with angles up to about 55. The distal ends of all of the fingers 62 terminate on thc circumference of an imaginary circle which is smaller in diameter then the .
964()3 smallest possible diameter of the metallic portions 32 of a givcn nominal si~e of cable 70.
Conrlector nut 16 has a generally hexagonal ruter configu-ration and an internal thread 64 therein. The outermost end 66 of c~nnector nut ]6 is turncd radially ;nwardly to form a flancJe and define both the nuts mini~llurn diameter surface 67 and an inwardly facing shoulder 68.
Grommet 18i is of generally tubular shape and is molded of rubber or some other desirable clastomer. Referring 10 specifically to Figure 2 it includes an outermost end surface 70, ?najor and minor outer diameters 71 and 72 (respectively) joined by an intermediaLy tapered surface 74, and also an innermost end surface 75. An axial hole 76 extends therethrough which is of a free or undeiormed diameter slightly greater than the outer.diameter of the plastic covering 38 of the largest cable 30 intended to be used with the connector. Minor ou'er diameter 72 fits loosel~y inside surface 50 of the connector body, and tapered surface 74 abuts a chamfer 78 at the outermost 20 edge of the _onnector body when originally assclllbled and prior to thc- final tiyhtening of the connector nut that clamps the cable in place.
: Washer 20 comprises anti-friction means, is preferrably constructecl of some low friction material such as Teflon has an outer d;ameter slig1~tly lar~3er than the ouLer diamcter of grolr~net :L8, and it's inller diameter is sliglltly lasger than the inner d;ameter of grommet 18. Dur;ng assembly of the entire c~ollllector a.ssemhly, w.lsher 20 :s positionecl be-tween .shoulder 68 on the connector nut and qromnlet surface 71.
~ q-' . .
~64(~3 As alluded to earlier, the conllector body subassemhly is ass-~mbled by first dropping retainer e]ement 14 lnto the outer end of conllector body 12 such that it lies against shoulder 54 with its fingers 62 slanting inwardly toward the clectrical bo~ end of t],e connector body. Prc-ferrably th(n a stakiT2g tool is drivcn i~to the outer end of the connestor body 12 to upset sollle of the ~laterial forming inncr surface 52 and thereby Eix retainer element 14 in that position. Compression grommet 18 and anti-friction washer 20 are dropped into connector nllt 16, andthen connector nut 16 is screwed up on threads 40 by hand until resistance is felt. The connector assembly is then shipped in this condition.
.
Jn use, the user has the option of first^attaching the connector a~sembly e.ther to an electrical box or to the cable. In either event, a final assembly.invo]ves strip-ping a designated length of the outer plastic coating 3B
from cable ?0 so as to expose a proper length of metallic portions 32, pushing this prepared end of cable 30 into the outer end of connector assembly 10 untiL the exposed edge of metallic portions 32 abuts internal surface 57 inside the connector body, and then tighten;.ng nut 16 until a11 threads are taken up and its leading edge abuts the conncctor body. .~s nut 16 rotates, it moves compression gro~mnet 18 toward the inner end of the conncctor causing it to be compressed radially inwardly c.o as to squee~e the plastic jacket 38 of the cable to both hold the cable 30 and seal it relative to the connector assembly. During the last fcw turns of nut 36, after compression grollunet 18 , ~lg~03 is already firmly in contact with jacket 38, cnb~e 30 is even f~-rther p~lshcd into the connec~or tow~td its elcctr;cal box end. Anti-friction washer 20 a:-oids direct contact between the driving surface 68 of the connector nut and the outer surface 71 of the compression grommet l8. This minimiZe9 resistive torque on the nut and permits the gromrnet 18 and cable 30 to move axially to the right without twisting.
!
Figure 5 shows a connector assembly designated generally 80 having a modified connector body 82 for use in conjunation with explosionproof applications where explosiollproof scals are required. ln the arrangement shown, the inner threaded end 83 of connector assembly 80 is screwed into a standard pottincl fitting 84. Potting fitting 84 has various side openings for introducing sealing material-therein (as is well known in the art), and it is conventionally located between assemoly 80 and some form of electrical box 86 or the like. Retainer element 14, connector nut 16, compression grommet 18 and anti-friction washer 20 are identical with the elements shown in Figures 1-4 and thus carry the same identifi-cation numbr,rs. ~he principal dif-erence lies in the connec-; tor body 82, and it will be noted that the inner end of that body illcludcs a relatively lar(;e e~ternal thrcad 85 which permits a l~rge diameter internal hole 86 to extend thro~lgh that end oE the conllector, its diameter being larger than :
that of the metallic portions of cable 30.
It will also be noted t~lat the netallic porli--ns 32 oE
::: :
cable 30 have been stripped of their plastic jacket 38 over a longer sp~n than in the earlier embodiment which permits ::
~ ~ a long r scgment of cable to be pushed tt~ongt, the connector ;~ ~ ~//~ ,, ~: , ~:
: ~
.~, ~
40~
assembl~ 80. This is desirable so that the stripped cnd of metallic port;(-ns 32 locate insi(1e pol:ting f;tting 84 so that thcy can he properly and thorougllly sealr-d with potting compound according to well known practLce.
Although the forcgoi.nq disclosure is detailed to ensure adequacy and aid ullderstandi.ng this is not intended to prejudice that purpose of a patent .~hich is to cover each new inventive concept therein no matter hGw others may later disguise it oy variations in form or additions or further improvements. The follo~cing claims are i:tended as the chief aid towards this purpose, as it is these that meet the reguirements of pointing out the parts, improvements or combinat~-~ns in which the inveDtlve c^ncepLs are ~ound.
~: :
:; :
:
~ '~ ~ .....
, :.
Claims (4)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS.
1. In a connector assembly for connecting metal clad cable to an electrical box, the connector assembly including a generally tubular body defining an outer end, an inner end, a larger and smaller inner diameter, and also including a stamped retaining element having an annular rim portion, the improvement comprising:
said retaining element having an outer diameter stamped to very nearly the same dimension as the larger inner diameter and having a plurality of narrow and relatively widely spaced fingers extending radially inwardly from said annular rim portion and numbering at least five, each finger being several times longer than its width, said fingers being canted away from the outer end of the assembly and cumulatively terminating radially inwardly in interfering relationship relative to the diameter of said metal clad cable whereupon said metal clad cable will significantly deflect said fingers when pushed therethrough inwardly but the radially innermost portions of said fingers dig into the cable so that it cannot be withdrawn thereafter, said tubular body having one internal diameter very nearly the same dimension as the outer diameter of said retaining element, and a shoulder adjacent said diameter for locating said retainer ring at a specific longitudinal position within the tubular body after it is assembled therein.
said retaining element having an outer diameter stamped to very nearly the same dimension as the larger inner diameter and having a plurality of narrow and relatively widely spaced fingers extending radially inwardly from said annular rim portion and numbering at least five, each finger being several times longer than its width, said fingers being canted away from the outer end of the assembly and cumulatively terminating radially inwardly in interfering relationship relative to the diameter of said metal clad cable whereupon said metal clad cable will significantly deflect said fingers when pushed therethrough inwardly but the radially innermost portions of said fingers dig into the cable so that it cannot be withdrawn thereafter, said tubular body having one internal diameter very nearly the same dimension as the outer diameter of said retaining element, and a shoulder adjacent said diameter for locating said retainer ring at a specific longitudinal position within the tubular body after it is assembled therein.
2. The improved connector assembly as defined in claim 1, wherein portions of said larger inner diameter at a plurality of spaced locations therearound have been upset therefrom and driven against said retaining element to hold same against said shoulder and prevent its removal from the tubular body.
3. The improved connector assembly as defined in claim 1, wherein said connector body has an internal and inwardly sloping surface between said shoulder and said inner end that is adapted to engage and center the end of said metal clad cable to provide additional and longitudinally spaced lateral stability for the cable as well as supplementary grounding therefor.
4. The improved connector assembly as defined in claim 1, wherein said tubular body is metallic and wherein said fingers are adapted to first deflect and then dig into the metal clad portions of the cable to thereby provide an effective electrical connection between the cable and the retaining element, said annular rim portion being sufficiently narrow radially that deflection of said fingers causes the retainer ring to contort and bite into the connector body, thereby completing the electrical grounding of cable to connector body.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000442172A CA1196403A (en) | 1983-11-29 | 1983-11-29 | Connector for use with jacketed metal clad cable |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000442172A CA1196403A (en) | 1983-11-29 | 1983-11-29 | Connector for use with jacketed metal clad cable |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1196403A true CA1196403A (en) | 1985-11-05 |
Family
ID=4126626
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000442172A Expired CA1196403A (en) | 1983-11-29 | 1983-11-29 | Connector for use with jacketed metal clad cable |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1196403A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108281836A (en) * | 2018-03-15 | 2018-07-13 | 天津艾琪兴海洋勘探科技发展有限公司 | A kind of plate armour type long-life pigtail line |
-
1983
- 1983-11-29 CA CA000442172A patent/CA1196403A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108281836A (en) * | 2018-03-15 | 2018-07-13 | 天津艾琪兴海洋勘探科技发展有限公司 | A kind of plate armour type long-life pigtail line |
| CN108281836B (en) * | 2018-03-15 | 2024-04-19 | 天津艾琪兴海洋勘探科技发展有限公司 | Armored long-life pigtail |
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