US3846738A - Cable connector - Google Patents

Abstract

A connector for attachment to the end of a coaxial cable having a core electrode and a conductive sheath electrode which includes a housing having an integral tubular skirt formed from four rearwardly extending tongues collectively formed with a rearwardly facing external cam surface. A tubular cap formed with a forwardly facing internal cam surface for engagement with the external cam surfaces of the skirt screws on to the housing so that interaction of the cam surfaces causes the tongues to be flexed radially inwardly into gripping engagement with the sheath electrode of a cable disclosed within the connector for electrical contact therewith. A radially inwardly compressible and electrically conductive collet sleeve coaxially disposed within the housing is adapted to receive the core electrode of the said cable and to be radially inwardly compressed by an electrically insulating compressible bushing disposed about the collet sleeve. The bushing has diametrically opposed projections extending through the tubular skirt defining rearwardly facing external cam surfaces for engagement by a second forwardly facing internal cam surface formed in the tubular cap such that radially inward movement is concurrently transmitted to the bushing and collet sleeve for simultaneous gripping of the core electrode and sheath electrode without any torsional shearing action between the said electrodes.

Description

Nepovim Nov.5,1974

[ CABLE CONNECTOR [75] Inventor: Zdenek Nepovim, Lindsay, Ontario,

Canada '[73] Assignee: Lindsay Specialty Products Limited,

Lindsay, Ontario, Canada [22] Filed: Apr. 5, 1973 [21] Appl. No.: 348,242

[52] US. Cl 339/177 R [51] Int. Cl H0lr 17/04 [58] Field of Search..... 339/60 C, 89 C, 90 C, 91 P, 339/94 C, 126 J, 177 R, 177 E, 273 R;

[56] References Cited UNITED STATES PATENTS 3,686,623 8/1972 Nijman 339/177 E 3,757,279 9/1973 Winston 339/177 R FOREIGN PATENTS OR APPLICATIONS 1,242,731 6/1967 Germany 339/177 R 1,109,914 4/1968 Great Britain 339/177 R Primary Examiner-Paul R. Gilliam Assistant ExaminerLawrence J. Staab [57 ABSTRACT I A connector for attachment to the end of a coaxial cable having a core electrode and a conductive sheath electrode which includes a housing having an integral tubular skirt formed from four rearwardly extending tongues collectively formed with a rearwardly facing external cam surface. A tubular cap formed with a forwardly facing internal cam surface for engagement with the external cam surfaces of the skirt screws on' to the housing so that interaction of the cam surfaces causes the tongues to be flexed radially inwardly into gripping engagement with the sheath electrode of a cable disclosed within the connector for electrical contact therewith. A radially inwardly compressible and electrically conductive collet sleeve coaxially disposed within the housing is adapted to receive the core electrode of the said cable and to be radially inwardly compressed by an electrically insulating compressible bushing disposed about the collet sleeve. The bushing has diametrically opposed'projections extending through the tubular skirt defining rearwardly facing external cam surfaces for engagement by a second forwardly facing internal cam surface formed in the tubular cap such that radially inward movement is concurrently transmitted to .the bushing and collet sleeve for simultaneous gripping of the core electrode and sheath electrode without any torsional shearing action between the said electrodes.

11 Claims, 4 Drawing Figures CABLE CONNECTOR BACKGROUND OF THE INVENTION The present invention relates to electrical connectors and more particularly is directed to connectors intended for securement to coaxial cables of the type used in CATV distribution systems.

- US. Pat. No. 3,668,6l 2 issued June 6, I972 discloses a connector for a coaxial cable in which the abutment of metal component parts on each other to transmit radial compression necessitates the application of considerable torque for securement of component parts together. It is a principal object of the present invention to provide a coaxial cable connector in which a direct metal on plastics abutment is attained to minimize and to reduce torque requirements for securing the connector to a cable. a

It is another important object of the present invention to provide electrical connectors particularly suitable for use in a CAT\/ system which provides a satisfactory seal against the ingress of moisture and dirt into the connector while providing effective electrical connections and obviating any torsional shearing action between the cable sheath and core electrodes.

And another important object of the present invention is to provide a connector design which will minimize critical tolerance requirements and thus enhance ease and economics of manufacture.

These and other objects of the invention and the manner in which they can be attained will become apparent as the description proceeds.

SUMMARY OF THE INVENTION comprises a hollow housing having integral therewith a rearwardly extending and peripherally discontinuous electrically conductive tubular skirt for radially inward compression into gripping engagement and electrical contact with the sheath electrode of a coaxial cable extending forwardly into said skirt, said tubular skirt being formed with a rearwardly facing external cam surface and a pair of diametrically opposed longitudinally disposed slots; a hollow tubular cap having associ Y ated therewith a forwardly facing internal cam surface for conjoint axial movement with said cap and for engagement with said rearwardly facing external cam surface of said tubular skirt when said cover sleeve is disposed coaxially around said tubular skirt and adapted to cause radially inward compression of said tubular skirt into gripping engagement and electrical contact with the sheath electrode of the coaxial cable disposed within said tubular skirt upon forward axial movement of said cap relative to said housing; co-operating means on said housing and on said cover sleeve for retaining said cover sleeve in a desired axial position on said housing; a radially inwardly compressible and electrically conductive collet sleeve mounted generally axially within said housing for receiving an exposed forward end portion of the core electrode of the coaxial cable inserted into said connector; and a radially inwardly compressible and electrically insulating bushing generally coaxially disposed around said collet sleeve having diametrically opposed projections extending through said slots formed in said tubular skirt, said projections defining rearwardly facing external cam surfaces whereby, on forward axial movement of said cap relative to said housing, said bushing and said collet are radially inwardly compressed to move said collet sleeve into gripping engagement and electrical contact with the core electrode of the cable concurrently with the compression of the tubular skirt for simultaneous gripping of the core electrode and sheath electrode without any torsional shearing action between the said electrodes.

BRIEF DESCRIPTION OF THE DRAWING Other features and advantages of the invention will become apparent from the following detailed description of the drawing, in which:

FIG. 1 is an exploded perspective view, partly cut away, of a cable connector of the present invention;

FIG. 2 is a longitudinal section ofthe cable connector shown in FIG. 1 illustrating a coaxial cable loosely inserted therein;

FIG. 3 is a longitudinal section of the connector shown in FIGS. 1 and 2 illustrating the connector in the closed operative position; and

FIG. 4 is a longitudinal sectional view of another embodiment of connector of the present invention shown preparatory to securement of the coaxial cable inserted therein.

DESCRIPTION oF THE PREFERRED EMBODIMENT With reference first to FIGS. 1 through 3, there is shown a connector, designated generally bynumeral 10, comprising ahollow housing 12 and acap 11 consisting of two components l4, 16 for receiving and electrically securing acoaxial cable 18 having asheath electrode 20 and forwardly projection exposedcore electrode 21.Housing 12 comprises amain body portion 13 with an hexagonal external configuration and a cylindricalinternal cavity 24 for receivingcollet 22 axially secured therein by frictionally fittedannular spacer 26.Spacer 26, formed of a rigid electrically insulating material, is secured withincavity 24 bycircular shoulder 25 crimped in the forward end ofhousing 12.Wire 27 ofcollet 22 extends through acentral opening 29 formed axially inspacer 26 andshoulder 31 ofcollet 22 abutsinner face 33 of said spacer.Collet 22 has a pair of diametrically opposedslits 35 longitudinally formed therein to permit compression ofthe end of the collet as shown in FIG. 3.

Housing 12 has a forward threadedportion 28 for securement to a box or the like enclosure, not shown, and a resiliently compressible sealing ring such as an O-ring 30, as shown more clearlyin FIGS. 2 and 3, seated inperipheral recess 31 for providing a water-tight fit with said box. Anexternal thread 32 is formed rearwardly ofcentral portion 13 for receivingmating threads 34 ofcap portion 14, a resilientlycompressible sealing ring 36 being positioned inperipheral recess 38 for providing a seal betweenhousing 12 andtubular sleeve 14 ofcap 11.

A tubular skirt is formed onhousing 12 by rearwardly extending peripherallydiscontinuous tongues 42 having a pair ofslits 43 and a pair of diametrically opposedslots 44 longitudinally formed therein.Slits 43 permit inward compression ofskirt 40 andslots 44 are adapted to receiveprojections 46 of bushing 48 centrally disposed therein.Bushing 48, positioned coaxial withcollet 22, is formed of an electrically insulating material. The exposedexternal cam surfaces 50 ofbushing 48 are shown rearwardly biased to receive forwardly extendingcam surface 52, defined on the inner wall oftubular sleeve 14, to permit radially inward compression of the bushing andcollet 22 for reasons which will become apparent as the description proceeds. It will be understood thatcam surfaces 50 can be formed by rounded or like projections extending throughslots 44 for engagement and inward compression by forwardly extendingcam surface 52 which, for example, can be frusto-conical or spherical in crosssection. Also,tubular skirt 40 can have a singlelongitudinal slot 44 formed therein to receive asingle bushing projection 46 for inward compression bysleeve cam surface 52.

The rearmost external surfaces of thetongues 42 oftubular skirt 40 are rearwardly biased to collectively form anexternal cam surface 43, such as a frustoconical surface shown, which is adapted to engage forwardly facing bevelledinternal cam surface 54 formed on the inner wall oftubular sleeve 14 for radially inward compression of said tubular skirt tongues wherebyserrations 56 formed on the inner surfaces of thetongues 42 ofskirt 40 will abut and positively engage the external surface ofsheath electrode 18 for gripping engagement and electrical contact therewith.

Cap portion 16. having an hexagonal peripheral surface for engagement by a wrench or the like tool, contains a threadedinner surface 60 to engage threadedmale surface 62 ofsleeve 14 at the rearward end thereof such that cap portion l6 can be screwed ontosleeve 14 for compression of resilientlycompressible sealing ring 64 therebetween and for rotation ofsleeve 14 to screwcap 11 ontohousing 12.

With reference to FIG. 3, it will be evident that the screwing ofcap 11 ontohousing 12 will axially advance the cap onto said housing to compressring 36, radially inwardly compress thetongues 42 oftubular skirt 40 ontosheath electrode 18, by mutual engagement of internalsleeve cam surface 54 withtongue cam surface 43, and to substantially simultaneously radially inwardly compress bushing 48, by mutual engagement of internalsleeve cam surface 54 onbushing cam surfaces 50, such thatcollet sleeve 22 will be compressed ontocore electrode 21.

ln use, the outerconductive sheath 20 andinsulation 23 ofcoaxial cable 18 are cut back to exposecore electrode 21 and the cable end loosely inserted into the connector, as shown in FIG. 2, such thatcore electrode 21 is positioned withincollet 22 and sheath electrode positioned withintubular sleeve 40 to abut the rear face of bushing 50. Thecap 11 is screwed tightly ontohousing 12 by rotation ofcap portion 16, and with reference now to FIG. 3, it will be seen thatskirt tongues 42 andcollet 22 will be inwardly compressed to grip and make electrical contact with the sheath electrode and core electrode respectively, in the manner described above, without relative rotational movement or shear between the two electrodes.

FIG. 4 illustrates another embodiment of the present invention, prior to locking in its operative sealed position, wherein a unitary cap is threaded ontohousing 12 whereby axial forward movement of the cap relative tohousing 12 by the screwing ofcap 80 thereon will radially inwardly compress the tongues oftubular skirt 40 andbushing projections 46 to positively electrically engage the cable sheath and core electrodes while compressing sealing O-ring 82 againsthousing 12 and compressing resiliently compressible sealing ring 84 againstskirt 40 andsheath 18 respectively to provide a watertight connection between the cable sheath electrode and connector interior.

The structure of the present invention provides a number of important advantages.Bushing 48 can be formed from a plastics material such as nylon and the connector housing and cap formed of a metal such as aluminum to provide little frictional resistance therebetween as compared to conventional cable connectors which utilize metal-on-metal bearing components. For example, components of conventional cable connectors are fabricated from aluminum because of aluminums corrosion resistance and low cost. However, aluminum on aluminum provides a poor bearing surface with high friction therebetween and, by the use of aluminum on nylon, the torque required to turn the connector cap onto the housing, normally requiring in the order of l6 foot-pounds, is reduced to about 3 footpounds. The direct abutment ofcaps 11 or 80 on bushing 48 further minimizes critical tolerance requirements of the connector with substantial savings in manufacturing costs.

What we claim as new and desire to protect by Letters Patent of the United States is:

l. A connector for securement to the end of a coaxial cable having a sheath electrode and a core electrode which comprises: a hollow housing having a rearwardly extending and peripherally discontinuous electrically conductive tubular skirt for radially inward compression into gripping engagement and electrical contact with the sheath electrode of a coaxial cable extending forwardly into said skirt, said tubular skirt being formed with an external cam surface and at least one longitudinal slot; a radially inwardly compressible and electrically conductive collet sleeve mounted generally axially within said housing for receiving an exposed forward end portion of the core electrode of the coaxial cable inserted into said connector; a radially inwardly compressible and electrically insulating bushing generally coaxially disposed around said collet sleeve and having at least one projection extending through said slot formed in said tubular skirt, said projection defining an external cam surface; a hollow tubular cap having associated therewith at least one internal cam surface for conjoint axial movement with said cap and for engagement with said external cam surface of said tubular skirt and said external cam surface of said bushing projection when said cap is disposed coaxially around said tubular skirt whereby on forward axial movement of said cap relative to said housing, said cap is adapted to cause radially inward compression of said tubular skirt into gripping engagement and electrical contact with the sheath electrode of the coaxial cable disposed within said tubular skirt and adapted to cause radially inward compression of said bushing and said collet sleeve to move said collet sleeve into gripping engagement and electrical contact with thecore electrode of the cable; said compression of the collet sleeve occurring concurrently with the compression of the tubular skirt for simultaneous gripping of the core electrode and sheath electrode without any torsional shearing action between the said electrodes; and cooperating means on said housing and on said cap for retaining said cap in a desired axial position on said housmg.

2. A connector as claimed in claim 1, in which said tubular skirt is longitudinally divided by at least one pair of diametrically opposed slits and by a pair of diametrically opposed slots into a plurality of peripherally spaced apart and rearwardly extending, radially inwardly and resiliently compressible tongues having an external cam surface formed collectively thereon, and said bushing having a pair of diametrically opposed projections formed thereon, said slots permitting said bushing projections to extend therethrough for engagement by an internal cam surface formed in the hollow tubular cap.

3. A connector as claimed in claim 2, in which said slits and said slots are equispaced about the tubular skirt.

4. A connector as claimed in claim 1, in which said tubular skirt is internally serrated for gripping engagement with the coaxial cable sheath electrode disposed therewithin.

5. A connector as claimed in claim 2, in which said tongues are internally serrated for gripping engagement with the coaxial cable sheath electrode disposed therewithin.

6. A connector as claimed in claim 1, in which said cap has a pair of axially spaced apart forwardly facing internal cam surfaces, one of said cam surfaces adapted to engage the external cam surface of the tubular skirt and the other of said cam surfaces adapted to engage the external cam surface of the bushing projection.

7. A connector as claimed in claim 2, in which said cap internal cam surface is a frusto-conical or spherical surface.

8. A connector as claimed in claim 6, in which said cap internal cam surfaces are frusto-conical or spherical surfaces.

9. A connector as claimed in claim 2, in which said bushing projections define rearwardly facing external cam surfaces.

10. A connector as claimed in claim 9, in which said tubular skirt external cam surface is a rearwardly facing frusto-conical or spherical surface.

11. A connector as claimed in claim 1, said tubular cap defining an annular space at its rearward end about the cable sheath electrode and a sealing ring disposed within said annular space for compression to provide a seal between said cap and said cable.

Claims (11)

1. A connector for securement to the end of a coaxial cable having a sheath electrode and a core electrode which comprises: a hollow housing having a rearwardly extending and peripherally discontinuous electrically conductive tubular skirt for radially inward compression into gripping engagement and electrical contact with the sheath electrode of a coaxial cable extending forwardly into said skirt, said tubular skirt being formed with an external cam surface and at least one longitudinal slot; a radially inwardly compressible and electrically conductive collet sleeve mounted generally axially within said housing for receiving an exposed forward end portion of the core electrode of the coaxial cable inserted into said connector; a radially inwardly compressible and electrically insulating bushing generally coaxially disposed around said collet sleeve and having at least one projection extending through said slot formed in said tubular skirt, said projection defining an external cam surface; a hollow tubular cap having associated therewith at least one internal cam surface for conjoint axial movement with said cap and for engagement with said external cam surface of said tubular skirt and said external cam surface of said bushing projection when said cap is disposed coaxially around said tubular skirt whereby on forward axial movement of said cap relative to said housing, said cap is adapted to cause radially inward compression of said tubular skirt into gripping engagement and electrical contact with the sheath electrode of the coaxial cable disposed within said tubular skirt and adapted to cause radially inward compression of said bushing and said collet sleeve to move said collet sleeve into gripping engagement and electrical contact with the core electrode of the cable; said compression of the collet sleeve occurring concurrently with the compression of the tubular skirt for simultaneous gripping of the core electrode and sheath electrode without any torsional shearing action between the said electrodes; and co-operating means on said housing and on said cap for retaining said cap in a desired axial position on said housing.

2. A connector as claimed in claim 1, in which said tubular skirt is longitudinally divided by at least one pair of diametrically opposed slits and by a pair of diametrically opposed slots into a plurality of peripherally spaced apart and rearwardly extending, radially inwardly and reSiliently compressible tongues having an external cam surface formed collectively thereon, and said bushing having a pair of diametrically opposed projections formed thereon, said slots permitting said bushing projections to extend therethrough for engagement by an internal cam surface formed in the hollow tubular cap.

3. A connector as claimed in claim 2, in which said slits and said slots are equispaced about the tubular skirt.

4. A connector as claimed in claim 1, in which said tubular skirt is internally serrated for gripping engagement with the coaxial cable sheath electrode disposed therewithin.

5. A connector as claimed in claim 2, in which said tongues are internally serrated for gripping engagement with the coaxial cable sheath electrode disposed therewithin.

6. A connector as claimed in claim 1, in which said cap has a pair of axially spaced apart forwardly facing internal cam surfaces, one of said cam surfaces adapted to engage the external cam surface of the tubular skirt and the other of said cam surfaces adapted to engage the external cam surface of the bushing projection.

7. A connector as claimed in claim 2, in which said cap internal cam surface is a frusto-conical or spherical surface.

8. A connector as claimed in claim 6, in which said cap internal cam surfaces are frusto-conical or spherical surfaces.

9. A connector as claimed in claim 2, in which said bushing projections define rearwardly facing external cam surfaces.

10. A connector as claimed in claim 9, in which said tubular skirt external cam surface is a rearwardly facing frusto-conical or spherical surface.

11. A connector as claimed in claim 1, said tubular cap defining an annular space at its rearward end about the cable sheath electrode and a sealing ring disposed within said annular space for compression to provide a seal between said cap and said cable.

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