Threaded crimp coaxial connector

[0001] 1. Field of the Invention

[0002] This invention relates to coaxial cable connectors. More particularly, the invention relates to a connector for coaxial cable with a solid outer conductor. The connector is coupled to the coaxial cable via threading and a connector body radial crimp operation.

[0003] 2. Description of Related Art

[0004] Coaxial cable connectors are used, for example, in communication systems requiring a high level of precision and reliability.

[0005] To create a secure mechanical and electrical interconnection between the cable and the connector, it is desirable to have generally uniform, circumferential contact between a leading edge of the coaxial cable outer conductor and the connector body. A flared end of the outer conductor may be clamped against an annular wedge surface of the connector body, via a coupling nut. Representative of this technology is commonly owned U.S. Pat. No. 5,795,188 issued Aug. 18, 1998 to Harwath.

[0006] Interlocking machine threaded coupling surfaces between the metal body and the coupling nut of U.S. Pat. No. 5,795,188 and similarly configured prior coaxial connectors significantly increase manufacturing costs and installation time requirements. Another drawback is the requirement for connector disassembly, sliding the back body over the cable end and then performing a precision cable end flaring operation, which retains the cable within the connector body during threading. Further, care must be taken at the final threading procedure and/or additional connector element(s) added to avoid damaging the flared end portion of the outer conductor as it is clamped between the body and the coupling nut to form a secure electro-mechanical connection between the outer conductor and the connector.

[0007] Alternative coaxial connector solutions, utilizing gripping and/or support elements about which the connector body is then radially crimped and/or axially compressed to secure an electromechanical interconnection between the outer conductor of the coaxial cable and the connector, are also known in the art. Commonly owned U.S. Pat. No. 6,840,803 issued Jan. 11, 2005 to Wlos discloses a crimp connector for a specific helically corrugated solid outer conductor cable. Longitudinal retention is obtained by threading a mating section of the connector body bore onto the helical corrugations of the outer conductor. A crimp operation is performed to deform the corrugation interconnection, thus creating a secure electrical interconnection and preventing unthreading. This configuration is usable only with specific outer conductor helical corrugation configurations, and in environments with wide temperature variations it may be susceptible to interconnection quality degradation over time as the different thermal expansion coefficients between the connector body and solid outer conductor act upon the interconnection during repeated expansion and contraction.

[0008] Competition in the coaxial cable connector market has focused attention on improving electrical performance and minimization of overall costs, including materials costs, training requirements for installation personnel, reduction of dedicated installation tooling and/or the total number of required installation steps and/or operations.

[0009] Therefore, it is an object of the invention to provide a coaxial connector that overcomes deficiencies in the prior art.

[0028] As shown in a first exemplary embodiment in FIGS. 1-9, a coaxial connector 1 according to the invention has a connector body 3 with a connector body bore 5. An insulator 7 seated within the connector body bore 5 supports an inner contact 9 coaxial with the connector body bore 5. The coaxial connector 1 mechanically retains the outer conductor 11 of a coaxial cable 13 inserted into the cable end 15 of the connector body bore 5 via an outer conductor thread 17 on the inner diameter of an outer conductor section 19 of the connector body bore 5 sidewall.

[0029] Further mechanical retention and/or alignment between the coaxial connector 1 and the coaxial cable 13 is provided by a jacket thread 21 located on the inner diameter of a jacket section 23 separated from the outer conductor section 19 by a transition 24 of the connector body bore 5 sidewall where the inner diameter of the connector body bore 5 is increased generally according to an expected jacket 33 thickness of the coaxial cable 13, enabling the jacket 33 to enter the jacket section 23 interfering only with the jacket thread 21 which is dimensioned to engage the jacket 33 at a desired thread depth.

[0030] A contact 25, best shown in FIG. 6, seated within a contact groove 35 of the connector body bore 5 is biased between the contact groove 35 and the outer diameter of the outer conductor 11. The contact 25 makes circumferential contact with the outer conductor 11, electrically coupling the outer conductor 11 across the connector body 3 to a connector interface 27 at the connector end 29. The connector interface 23 may be any desired standard or proprietary interface.

[0031] After the coaxial cable 13 is threaded into the connector body bore 5 until the leading edge of the outer conductor 11 contacts the cable stop 31, a crimp tool is applied to an outer diameter crimp section 37 of the connector body 3 to apply a crimp action that deforms the connector body 3 around the coaxial cable 13, preventing unthreading of the coaxial cable 13 from the connector body 3.

[0032] One skilled in the art will appreciate that the cable end 15 and the connector end 29 are descriptors used herein to clarify longitudinal locations and contacting interrelationships between the various elements of the coaxial connector 1. In addition to the identified positions in relation to adjacent elements along the coaxial connector 1 longitudinal axis, each individual element of the connector and/or section of the connector body bore 5 has a cable end 15 side and a connector end 29 side, i.e. the sides of the respective element or section that are facing the respective cable end 15 and the connector end 29 of the coaxial connector 1.

[0033] As best shown in FIG. 3, the connector body 3 may be formed as a unitary monolithic element. The connector body bore 5 is dimensioned to receive the coaxial cable at the cable end 15 until a leading edge of the outer conductor contacts a cable stop 31 that projects radially inward at least to an inner diameter of the outer conductor 11. Before reaching the cable stop 31, the outer conductor 11 enters the outer conductor section 19 and engages the outer conductor thread 17 that threads into the solid outer conductor either via self-tapping thread or the like that gouges into the outer diameter of the outer conductor 11, or alternatively via a blunt thread that deforms the outer conductor radially inward as it is threaded on, forming a helical corrugation interlocked with the connector body 3. As the outer conductor 11 is threading into the outer conductor section, the jacket 33 of the coaxial cable 13 enters the jacket section 23 and engages the jacket thread 21.

[0034] A profile of the outer conductor thread 17 and/or jacket thread 21 may be dimensioned with a cable end face 38 and a connector end face 40. The cable end face 38 and the connector end face 40 may be provided with an equal angle to one another, or alternatively the connector end face 40 may be arranged with a slope, with respect to the outer conductor section 19, that is steeper than the cable end face 38 to improve the longitudinal retention of the thread upon the outer conductor 11 and/or jacket 33, for example as shown in FIGS. 4-7.

[0035] In further embodiments, the outer conductor thread 17 and/or jacket thread 21 may be formed with longitudinal groove(s) 45 for example as shown in FIG. 3. The longitudinal groove(s) 45 providing additional grip surfaces for outer conductor 11 material to flow into under the crimp force, further rotationally interlocking the outer conductor 11 and connector body 3 after the crimp operation has been applied.

[0036] One skilled in the art will appreciate that the combination of connector body 3 to outer conductor 11 and the connector body 3 to polymer material of the jacket 33 provides an extended interconnection between the coaxial cable 13 and the connector 1 with both secure longitudinal mechanical retention and close longitudinal alignment therebetween.

[0037] Before contacting the cable stop 31, the outer conductor 11 passes under the contact 25. The bias between the contact 25 and the outer conductor 11 provides an enhanced circumferential electrical contact with reduced susceptibility to electrical noise generation should the quality of the mechanical interlock provided by the outer conductor thread 17 and jacket thread 21 become compromised over time.

[0038] As best shown in FIGS. 4 and 6, the connector end 29 side of the contact groove 35 may be angled towards the connector end 29, creating a ramp surface 51 for the contact 25, enabling the contact 25 to be momentarily urged upward and outward as the outer conductor 11 contacts and/or passes beneath the contact 25 during insertion into the connector body bore 5, reducing the chance that the leading edge of the outer conductor 11 will bind against the contact 25 and/or reducing the insertion force needed during interconnection. A similar groove ramp surface 51 configuration (see FIG. 3) may also be applied to a seal groove 39 proximate the cable end 15 of the connector body bore 5. The seal groove 39 receiving a seal 41, such as an o-ring, to environmentally seal the connector body bore 5 against the jacket 33.

[0039] The area of the outer conductor 11 contacted by the contact 25 may be supported by an extended portion of the insulator 7 dimensioned to fit within the outer conductor 11 proximate the outer conductor 11 inner diameter. Thereby, should any deformation of the outer conductor 11 occur in response to the bias exerted by the contact 25, the outer conductor 11 is supported by the insulator 7.

[0040] Alternatively, the insulator 7 may be formed with a plurality of deflectable insulator finger(s) 42 extending towards the cable end 15, for example as shown in FIGS. 8 and 9. Where the contact 25 is within the crimp section, the radial inward crimp action drives the contact 25 radially inward against the outer conductor 11 and the outer conductor 11 against the insulator fingers 42, driving the insulator fingers 42 inward to bias the inner contact 9 against the inner conductor 43, enhancing the electro-mechanical interconnection therebetween.

[0041] The inner contact 25 may be applied as a helical coil spring, for example as shown in FIG. 6. Alternatively, the contact 25 may be provided as a ring with a V-Shaped (FIGS. 10 and 11) or U-shaped (FIGS. 12-14) cross section, for example, with a plurality of spring finger(s) 44 or band(s) 46, respectively, projecting inward.

[0042] An alternative support for the leading edge of the outer conductor 11 may be incorporated into the connector body bore 3 as shown for example as shown in FIGS. 15-16. An outer conductor lip 47 projects towards the cable end 15 of the connector body bore 5 from an inner diameter of the cable stop 31, the outer conductor lip 47 forming an annular cable groove 49 open to the cable end 15 of the connector body bore 5. As best shown in FIG. 16, a lead edge of the outer conductor lip 47 may be formed with an angled ramp surface 51 operable as a guide for the leading edge of the outer conductor 11 during insertion into the connector body bore to seat the leading edge of the outer conductor 11 into the annular cable groove 49 with reduced chance of interference/binding upon the outer conductor lip 47.

[0043] Although the various embodiments have been demonstrated with respect to a smooth walled solid outer conductor coaxial cable 13, one skilled in the art will appreciate that the connector 1 may also be used with corrugated solid outer conductor coaxial cable 13. As shown for example in FIG. 17, the corrugation peaks of a corrugated solid outer conductor 11 are similarly engaged by the outer conductor thread 17 and the jacket thread 21 engages the jacket 33 to provide longitudinal retention.

[0044] A method for installing the coaxial connector 1 includes the steps of preparing the end of the coaxial cable 13 according to the connector 1 configuration, and stripping back a desired portion of the jacket 33. The end of the coaxial cable 13 is then inserted into the connector body bore 5 and the outer conductor 11 threaded upon the outer conductor thread 17 until the jacket 33 contacts the jacket thread 21, then threading the outer conductor thread 17 onto the outer conductor 11 and the jacket thread 21 onto the jacket 33 until the leading edge of the outer conductor 11 passes under the contact 25 and abuts the cable stop 31. Finally, a crimp force is applied to the crimp section 37 to deform the connector body 3 radially inward around the coaxial cable 13, thus inhibiting unthreading of the connector body 3 from the coaxial cable 13. If the coaxial connector 1 is equipped with the insulator finger 42 configuration, as the crimp force is applied, the inward movement of the connector body 3 drives the outer conductor 11 inward against the insulator fingers 42 and the insulator fingers 42 inward against an interconnection between the inner contact 9 and the inner conductor 43.

[0045] One skilled in the art will appreciate that the prior manual cable end flaring operations and any required disassembly/reassembly of the various connector elements around the coaxial cable end during installation have been eliminated.

[0046]

Table of Parts
1	coaxial connector
3	connector body
5	connector body bore
7	insulator
9	inner contact
11	outer conductor
13	coaxial cable
15	cable end
17	outer conductor thread
19	outer conductor section
21	jacket thread
23	jacket section
24	transition
25	contact
27	connector interface
29	connector end
31	cable stop
33	jacket
35	contact groove
37	crimp section
38	cable end face
39	seal groove
40	connector end face
41	seal
42	insulator finger
43	inner conductor
44	spring finger
45	longitudinal groove
46	band
47	outer conductor lip
49	cable groove
51	ramp surface.

[0047] Where in the foregoing description reference has been made to materials, ratios, integers or components having known equivalents then such equivalents are herein incorporated as if individually set forth.

[0048] While the present invention has been illustrated by the description of the embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative apparatus, methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departure from the spirit or scope of applicant's general inventive concept. Further, it is to be appreciated that improvements and/or modifications may be made thereto without departing from the scope or spirit of the present invention as defined by the following claims.