Crimped coaxial cable termination
US 3103548 A
Description (OCR text may contain errors)
Sept.' 10, 1963 c. w. coNcELMAN CRIMPED coAxIAL CABLE TERMINATION Filed Nov. 1e, 1961 INVENTOR ATTORNEY \\L www NN l QW N NQWN Sv MQ \W LI Q -T UHF j to clamping;
3,103,548 CRiMlED CUAXlAL CABLE TERMINATIN Carl W. Concelman, Danbury, Conn., assigner. to VA.rnplieiiiel-lorg Electronics Corporation, Broadview,
Ill., a corporation of Delaware Filed Nov. 16, 1961, Ser. No. 152,752 Claims. (Cl. 17d- 89) VThis invention relates to an improved electrical con- Knector designed for connection with electrical coaxial cable and, in particular, relates to means for fastening such i cable to the connector and to provide a good ground connection for the braid wire.
1t is a principal object of the invention to provide a coaxial connector structure incorporating an improved clamping end for providing a good mechanical and electrical connection to the cable. The cable clamping structure is especially well suitedto small lcoaxial cables. With present art, it is difficult to provide a cable clamping action that will withstand cable flexing and handling in clamping means incorporated in the structure of the connector. The improve-d clamping means is equipped to provide a lgood low resistance contact between -the cable braid wire andthe connector shell. The clamping means is also characterized to clamp thecable without any appreciable deformation to the cable to avoid rmpedance discontinuities. I t
It is a further object of the invention to provide a coaxial connector designed for connection with electrical coaxial cable wherein the connector includes a mechanically simple structure for clamping the Vcable to the connector by a standard crimping tool and whereby such attachment is reliable in holding the cable fastened to the connector and said cable is Igripped against pull-out.
It iis a further object of the invention to provide a coaxial connector clamping structure that does not appreciably deform the cable clamped thereby to avoid impedanfce discontinuities. The :clamping structure employs a longitudinally slotted ferrule or clamping sleeve mounted on the cable, which sleeve is dimensioned so that a hexagonal 'crimp .closes its slot to prevent -further closure ofthe clamping sleeve over the cable.
lIt is a yfurther object of the invention to provide a small, neat appearance cable cla-mp structure that does not require the addition of an elastic boot or sleeve to present a finished appearance.
It is a further object of the invention tov provide a coaxial connector strulcture incorporating an improved clamping end for fastening electrical coaxial cable to such connector by a crimping tool and wherein the structure of such clamping end is relatively simple with respect to fabrication and use and is particularly suitable for connectors and' cables of small size, but is not limited to small size transmission line cable and coaxial connector components.
Further objects and advantages will become apparent from the :following description of the invention taken in conjunction with the figures, in which: f
FIG. 'l is a longitudinal elevation in section of a corinector incorporating the principles of the invention prior FIG. 2 is a fragmentary'section illustrating the clamp- United States Paten-t O alessia ice ing components of the connector acting upon the cable after the crimping action; and
FIG. 3 is a perspective view of the clamping sleeve prior to crimping.
Reference is made to the iigures for an embodiment of a connector 10 incorporating the principles of the inven- Y tion. The longitudinal shell V11 is a conductive tubular 119 abuts against an internal shoulder ',1 in bore 12. The
section 20 of bore 12 between wall 19 and shell open end 1i4 is equipped to receive the coaxial cable 22 to be connected -to connector 10.
Connector `10 is designed to connect to electrical coaxial -cable 22 depicted as having an inner conductor 23 surrounded by a coaxial insulator Z4, which insulator 24 in turn is surrounded by an outer conductor braid 25, whereas braid 25 is covered by an outer insulating and protective sheath 26.
The remainder of the connector clamping means includes a tubular wall rferrule or sleeve 27 extending axially between opposite first and second ends 2S, 29. Sleeve 27 ttnay be made of a deformable metal, such as brass. Sleeve 27 has a through bore 30 for mounting same over cable 22. The front por-tion of sleeve bore 3i) is serrated by threads or ridges 31 to provide a good grip around the outer cable surface aft-er a crimping action is completed. Tubular sleeve 27 also has a longitudinal slot 32 extending along its wall between its opposite ends 2'8', 29. Sleeve 27 is idimensioned for easy mounting over cable 22 prior to the crimping step.
A radially raised V-shaped ridge 3-3 extends annularly about the outer surface of sleeve body 27. Ridge 33 is made up of two inclined faces 33a, 33h. The tubular wall of shell 11 includes a corresponding V-shaped annular recess 34 intermediate the ends of bore section 20. Recess 3'4 is vformed by inclined faces 34a, 34th.
In preparation of attaching cable 22 to connector 10, cable sheath 26 is cut short to terminate within the sleeve front end 28 upon mounting the latter on cable 22, as shown in FIG. l. The end of cable insulator 24 is cutoilE to bare -a length of cable inner conductor 23 for attachment to connector contact 17. The portion of cable vbraid extending from the sleeve front end 2S is folded around 'and pulled back over the outer surface of the sleeve wall. The end of braid 25 may be cut oi to terminate same to the left of sleeve ridge 33. Further-A more, the forward end of cable insulator 24 passes through a central opening in wall 19 and is cut square to Iabut against -a stop shoulder in the interior of bore 12 provided by the rear of cont-act 17 and insulator 16 upon insertion of cable 22 and the sleeve 27 mounted thereon into shell bore section 20. When the assembly of cable 22 and sleeve 27 is so inserted, the folded over portion of braid 25a is wedged between radial wall 15 and the sleeve front end 28, ,Whereas the pulled 'back portion of braid 25h is wedged between sleeve 27 land the ibore surface of shell section 26.
Ridge 33'iand recess 34 are predeterminately located along their respective bodies so Atbiat upon seating the ias- Isernbiy of cable 22 and sleeve 27 in bore section 20 prior to crimping laction,.the vertical center line 35 of recess 34 is slightly to the left of the vertical center line 36 of ridge cable sheath 26 when slot 32 closes.
33, asshof/n in FIG. l, `whereby the rearinclined ridge and recess faces 33h and 34h, respectively, are juxtaposed 1 and closely spaced apart.
about its axis. The crimp extends longitudinallythe length of wall portion 37.'r Crimpingfaction constricts` f this Isection 37 of tubular wall along its longitudinal vaxis and lcircumferentially 360 about its longitudinal axis to cause inclined recess face 34h to close against inclined ridge vhace 33h. By virtue of the geometry of the V shaped ridge 33 and recess 34, la force is transmittedto sleeve face 33h from shell face 34h which pushes sleeve 27 in a forward direction to clamp braid 25 tightly against Wall 19. Since the lcrimping action is applied circumferentially360" around shell wall section 37, the constricting force', depicted by the arrows in FIG. 3, also closes sleeve slot 32 which accomplishes :a tight grip of cable 22 by serrations 3l. Furthermore, closing of recess face 34h against 4sleeve face 3311 also locks sleeve `"lheforvv-ard end of shell il includes a threaded coupling nut 41 for attaching connector 10 to a ini-ating connector.
The clamping end of connector shell 1l may -=be standardized with respect to its dimensions for use ywith cables of diiferent sizes. For a smaller diameter cable,
clamping sleeve 27 .will Ihave a relatively thickervcrosssectional Wall, that is to say, the dimension A will beV greater to accommodate smaller cable. Conversely,rthc
`cross-sectional thickness Av of sleeve wall is decreased to y accommodate cableV of larger diameter. f
FIG. 2 shows the clamped endv of connector after crimping. The outer'surface of connector wall 37 is partially flattened to a hexagonal shape 'by the crimping tool. The force is transmitted to close recess face 34b against nidge'face 331). The force tends to push sleeve 27 forward to squeeze the radial portion of braid 25a .between sleeve front end 23 and Wall 19; Whereas, the pulled back" section of braid ZSb is squeezed between the cylindrical wall of sleeve 27 and the surface of bore lsec- `tion 20. This assures 'a good low .resistance contact between cable braid 25 and connector shell 11. The crimping action causes the sleeve serrations 31 to close upon However, closure of slot 32 stops further constriction of sleeve 27 against cable 22 to prevent `deformation of the cable insulation 24 and a resulting impedance discontinuity. The assembly is `also locked by virtue of the geometry of the contiguous and accidental pull out of cable 22.
Although recess 34 and ridge 33-iare Vsshaped in the illustrated embodiment, it wouldl be entirely within theY tubular metal jacket as its outer conductor in place yof av braided lshield and protective jacket as `illustrated herein. For cable with an outer solid tubular metal jacket, sleeve 27 "closes lto grip tightly the `outer metal jacket upon crimping, whereby the forward end of such jacket will bottom against wall 19 to effect a good ground connection to connector shell ll. In addition, a good ground connection is also achieved lby increasing the dimension A of sleeve so that after crimping, the outer surface of sleeve 27 also makes good contact with the surrounding f `Wall portion 37. Further electrical connectionis obtainedV by recess face 34b closing Iagainst ridge face 33b after crimping. It is also `submitted that the principles of the foregoing clamp structure is applicable to nonelectrical coupling devices, Vfor example, for connecting tubular piping to a coupling device, which device includes the features of the sleeve 27 and recess and ridge lt is intended that all matter -contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and` not in -a limiting sense.
' What is claimed is:
1. A coaxial connector clamping means Vfor fastening an electrical coaxial cableV to the .connector wherein the cable has a conductive inner conductor surrounded by successive layers of insulator, a braided outer conductor and an insulator sheath, the combination comprising, a tubular wall conductive'shell deiining the connector outer conductor, said shell having an axial through bore extending from an open rearward end to its front end,.the axial section of bore adjacent said shell lrearward end being equipped for receiving the end of coaxial cable to be connected to said connector, radial wall means in the interior of said bore section and confronting the open rearward end of said bore, said bore section also having an inclined face recessed in the Wall of said shell, said inclined face being at an angle withthe axis offsaid bore substantially to confront the interior end of said section, p
Y braid extending out from the front end of said sleeve and folded back over the outer surface of said ysleeve wall for insertion of the cable and said sleeve mounted thereon in seated relationship in said connector'bore section, a portion of the folded back braid being pressed between Asaid 'radial wall and the front end of said sleeve, means on said sleeve extending substantially radially for confront ing said inclined face to effect mutual engagement therebetween characterized to urge said `sleeve in anV axially forward direction in said shell bor-e upon a circuinferen` tial constricting force being applied Vto said shell, said sleeve being cons-tricted to close upon said cableV upon inclined faces 33b, 34h to prevent escape of sleeve 27 circumferentially crimping the wall of said shell sur-V rounding said bore section, constriction of said sleeve being taken up by closure of saidslot, said crimping force also causing said inclined face to engage said means on said sleeve for urging said sleeve in a 4forward Vdirection to clamp said braid tightly against said radial wall and to lock said sleeve in said connector. Y
2. A'coaxial connector clamping means for fastening an electrical coaxial cable to theV connector wherein ther cable has an inner conductor and a braid outer conductor separated. by insulator means, the combination comprising, a tubular wall shell defining the connectorV outer conductor, said shell having an internal sectionof bore extending from the open end of saidshell, shoulder means in the interior of said bore section, said bore section being equipped -for reciving the coaxial cable to be conneoted to said connector, said bore section having a recessed inclined tace extending into the wall `of said shell,
effect mutual engagement vlltherebetween characterized toy urge said sleeve in an axially forward direction upon a circumferential yconstricting force being applied -to said shell surrounding said bore section, constriction of said cable upon circumferentially crimping the wall of said shell surrounding said bore section, constricting of said sleeve is taken up by closure of said slot means, closure of said slot means substantially halts furtherconstriction of said sleeve on said cable, the crimping force causes said Ainclined face to engage said means on said sleeve for urging said sleeve in a direction to clamp said braid against said shoulder and also to lock said sleeve in said connector.
3. A connector as defined in claim Z wherein, the bore of said sleeve including serrations for Itightly gripping said cable upon constriction of said sleeve.
4. A connector as dened in claim 2 vwherein7 said recess is made up of juxtaposed faces defining an annular V-shaped recess, and said sleeve means including a radially raised ridge having inclined -i-aces forming a V- shaped ridge juxtaposed said recess upon insertion of said sleeve into said bore section.
5. Means as defined Vin claim 4 wherein, said sleeve bore including serrations for tightly gripping said cable upon constriction of said sleeve, and the portion of the folded back braid over the outer surface of said sleeve Wall being squeezed tightly between said sleeve and tubular wall of said shell upon crimping of same.
References Cited in the tile of this patent UNITED STATES PATENTS 2,941,028' Edlen et al. June 14, 1960