GB2155704A

GB2155704A - Crimped connector for coaxial cable

Info

Publication number: GB2155704A
Application number: GB08406332A
Authority: GB
Inventors: Donald J Levine; Victor L Salvador
Original assignee: KINGS ELECTRONICS CO Ltd
Current assignee: KINGS ELECTRONICS CO Ltd
Priority date: 1984-03-10
Filing date: 1984-03-10
Publication date: 1985-09-25
Also published as: GB2155704B; GB8406332D0

Abstract

A sleeve (8) is crimped onto the outer conductor (12) of a co-axial cable to provide an electrical and mechanical joint having low RF leakage and so little dimensioning effect on the cable that transmission loss due to internal reflection is maintained acceptably low. The sleeve (8) has radially inwardly extending protrusions in the form of flutes (10), a combination of flutes and a screw thread (not shown) or a combination of screw threads of opposite hand (not shown) and its inner diameter before crimping is just greater than the diameter of the conductor. The protrusions bite into the conductor on crimping. <IMAGE>

Description

SPECIFICATION Crimped connector The invention is directed to an improved arrange mentforattaching a semirigid coaxial cable to a connector.

In the coaxial cable art involving the transmission of high frequency signals, at least two problems arise when two cables are to be interconnected or when a cable isto be connected to a terminal device. The first is the mechanical strength ofthe connectors and the second concerns the electrical effects ofthe interconnection such as maintaining an acceptably low radio signal power leakage through the cable-connector interface and minimum transmission losses due to internal reflections. These problems have reasonably been solved by direct soldering ofthe outer cable conductorto the connector or by a clamp and collet type of attachment means. Another arrangement isto knurl the outer surface of a semirigid outer conductor to make an interference force fit to the connector body.

It is an object ofthe present invention, in the case of a coaxial cable having a semirigid outer conductor, to provide a simple and improved interconnection between the coaxial conductor and connector which avoids the mechanical parts and/or mechanical steps heretofore deemed necessary while still meeting satisfactory mechanical and electrical criteria.

Afurtherobjectofthis invention isto provide means establishing a mechanically strong and electrically satisfactory connection between a semirigid coaxial cable and connectortherefor, which does not involve the step of soldering the cable to the connector, which avoids the clamp and collettype of attachment, and which does not require the scoring or knurling ofthe outer surface ofthe outer cable conductorto provide an interference force fit with a connector body.

More specifically it is an object ofthis invention to provide a simple crimp connection between a connector body and the outer conductor of a coaxial cable which is sufficiently resistant to pull-off, twisting and slipping and atthe same time has acceptably Itw power leakage and transmission losses.

The aforesaid objects are attained by providing the body to which the coaxial cable is to be attached with a sleeve having inwardly directed projections in the form for example of flutes and/orthreads which, upon crimping ofthe sleeve, will bite into the outer surface of the outer conductor of the coaxial cable to provide a mechanical connection of sufficient strength while effecting an electrical connection having suitably minimum losses.

The above objects and advantages of the present invention will be more clearly demonstrated by the detailed description thereofwhich follows, and as more particularly illustrated in the accompanying drawings in which: Figure 1 is an end view of a connector having a crimpablefluted sleeve in accordance with one form odour invention; Figure 2 is a longitudinal cross-sectional viewofthe connectortaken along the line 2-2 of Figure 1; Figure 3 is a longitudinal cross-sectional view similarto Figure 2 showing the connector embracing a semi-rigid coaxial cable; Figure 4 is an enlarged transverse cross-sectional view taken along the line 4-4 of Figure 3; Fig. 5 is an end view similarto Fig. 1 illustrating a modified form ofthe invention;; Fig. 6 is a longitudinal cross-sectional view taken along the line 6-6 of Fig. 5, and Fig. 7 is a longitudinal view in partial cross-section showing a still further modified form of the invention as applied to another connector body.

Figs. 1-4 illustrate the application of one form ofthe present invention to the attachment of a semirigid coaxial cable to a conventional connector body. A typical female connector is illustrated having a threaded outershell 2, and internal supporting insulator4 and a central flexible connector 6. The threaded shell 3 and connector 6 are adapted to be mechanically and electrically connected to a typical male connector (not shown).

Extending longitudinally outwardlyfrom the connector body 2 supported by and attached thereto as by soldering orothersuitable means is a sleeve 8 having a plurality of radially spaced, inwardly projecting integral flutes 10. Figs. 1 and 2 show the construction of a connector according to this inventon prior to the insertion ofand/orconnection to a semirigid coaxial cable. The internal diameter "d" between flute ends is slightly greater than the external diameter of the coaxial cabletowhich connection isto be made. In other words, the cable can slip in easily with the center conductorto be attached to central conductor 6 in a mannerwell known in the art.

Figs. 3 and 4 show a semirigid coaxial cable 12 crimped within the sleeve 8 of connector 2. While not necessary to the effectiveness of the invention, a simple known hexagonal die may be used in the crimping operation with the result that not all of the flutes may bite into the outer conductor, as is more clearly shown in Fig. 4.

Utilizing a crimp connector as illustrated in Figs. 1-4, tests showed an RF leakage of less than 90 decibels while the cable illustrated withstood pull testfrom 60 to 1301bs.

While sleeve 8to be crimped about the coaxial cable 12 is shown as soldered or otherwise attached to connector body 2, it may be formed unitarilytherewith with the sleeve section zone annealed to permit deformation.

Avariation ofthe arrangement shown in Figs. 1-4 is illustrated in Figs. 5and 6, the sole difference being thatflutes here designated as 10' arethreaded or transversely scored as indicated at 20. This provides an additional biting surface and in fact can triple the pull resistance without adversely affecting the RF leakage.

Still another version of our invention is illustrated in Fig. 7 in which sleeve 30 attached to a connector body 32 is provided with internal cross-threads 34, (intersecting right and left hand threads) longitudinal fluting in this case being eliminated. This form of invention provides resistance to pull comparable to the threaded fluting previously described and there is no loss in the RF leakage characteristics. We have also shown in Fig. 7 the use of a weatherproof gasket to preventwater leakage between cable and sleeve. The outer end of sleeve 30 is provided with a recessed annulus 36 in which is placed an annular gasket 38, preferably of soft rubber or sealing compound which will be pressed against the outerconductorofthe cable (not shown).

The invention above described meets all the criteria and objects previously stated. The invention is applicable to all sizes ofsemirigid coaxial cable. Cable preparation is simple and it is trimmed according to standard procedures. The sleeve or crimp body is preferably round. Compression of the sleeve to a depth of between .006" to .010" is sufficientto provide adequate mechanical strength without severely deforming the center dielectric ofthe cable.

The invention is not intended to be limited to the specific examples described and illustrated, but only as required by the claims which follow.

Claims

1. In an electrical connectorofthetype adapted two receive a coaxial cable having an inner conductor surrounded bya dielectric and in turn by a semirigid outer conductor, wherein center connecting means are mechanically and electrically attached to the inner conductor and coupling means are electrically and mechanically attached to the outer conductor, the improvement comprising a radially deformable sleeve forming part of said coupling means and surrounding the semirigid outer conductorofthe cable to be attached, and means forming projections within said sleeve extending radiallyinwardlyto immediatelysurround the semirigid outer conductor, whereby upon crimping of said deformable sleeve said projections bite into the outer surface of said semirigid outerconductorand attach the same to the coupling means of said connector against rotational or longitudinal movement.

2. In an electrical connectoraccordingto claim 1, in which said integral projections are circumferentially spaced one from the other aboutthe inner periphery of said sleeve and extend longitudinally as flutes within said sleeve where the sleeve contacts the semirigid outer conductor.

3. In an electrical connectoraccordingto claim 2 in which the inner ends ofsaid projections are threaded.

4. In an electrical connector according to claim 1, in which said integral projections are formed as cross-threads.

5. in an electrical connector according to claim 1,2, 3 or4 in which the outer end of said sleeve is formed with an internal annulus having a diameter greater than the external diameter ofthe said outer conductor, in combination with an annular soft rubber gasket placed in said annulusaboutsaidouterconductor.