1. Field of the Invention
This invention relates to electrical cable connectors. More particularly, the invention relates to a coaxial connector with improved passive intermodulation distortion (PIM) electrical performance and mechanical interconnection characteristics.
2. Description of Related Art
Coaxial cable connectors are used, for example, in communication systems requiring a high level of precision and reliability.
To create a secure mechanical and optimized 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 body. Representative of this technology is commonly owned U.S. Pat. No. 5,795,188 issued Aug. 18, 1998 to Harwath.
Alternative forms of connector to cable end electro-mechanical interconnection include various grip surface arrangements of the connector which contact and grip the inner and/or outer conductor of the coaxial cable.
During systems installation, rotational forces may be applied to the installed connector, for example as the attached coaxial cable is routed towards the next interconnection, maneuvered into position and/or curved for alignment with cable supports and/or retaining hangers. Rotation of the coaxial cable and coaxial connector with respect to each other may damage the connector, the cable and/or the integrity of the cable/connector inter-connection. Further, once installed, twisting, bending and/or vibration applied to the interconnection over time may degrade the connector to cable interconnection and/or introduce PIM.
Prior coaxial connectors typically utilize a coupling and/or back body as a driving means for clamp and/or grip interconnection mechanisms of the connector and/or as an ease of assembly means for enabling easy insertion of internal elements within the connector, such as seals and/or electrical contact elements. Couplings and/or back bodies may also include elastomeric environmental seals compressed into a sealing configuration against the coaxial cable via a compression action with respect to the connector body. Representative of this technology is commonly owned U.S. Pat. No. 7,077,699 issued Jul. 18, 2006 to Islam et al. Although an environmental seal compressed to extend radially inward into contact with a jacket of a coaxial cable may provide a stabilizing effect upon the coaxial connector, the environmental seal is typically formed from an elastic material to enable an elastic sealing deformation contact against the jacket. Therefore, any stabilizing effect obtained from the environmental seal is limited.
Prior coaxial connectors are typically configured for interconnection with a particular coaxial cable, for example a smooth outer conductor coaxial cable or a corrugated outer conductor coaxial cable, thereby providing dedicated coaxial connector models for each type of coaxial cable increase design, manufacturing and inventory costs.
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 the total number of required installation steps and/or operations.
Therefore, it is an object of the invention to provide a coaxial connector that overcomes deficiencies in the prior art.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, where like reference numbers in the drawing figures refer to the same feature or element and may not be described in detail for every drawing figure in which they appear and, together with a general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the invention.
The inventor has recognized that movement and/or skewing of alignment between the connector and coaxial cable may generate unacceptable levels of PIM and/or otherwise compromise the electromechanical interconnection, for example as contact surfaces shift relative to one another and/or less than uniform circumferential contact occurs between the electrical contacting elements of the connector and the inner and/or outer conductors.
A stabilizing assembly 1 with a connector to cable interconnection stabilizing functionality is demonstrated in
One skilled in the art will appreciate that connector end 5 and cable end 7 are applied herein as identifiers for respective ends of both the coaxial connector 10 and the stabilizing assembly 1 and also of discrete elements of both described herein, to identify same and their respective interconnecting surfaces according to their alignment along a longitudinal axis of the coaxial connector between a connector end 5 and a cable end 7.
The coupling body 3 may be configured to perform connector functions in concert with the connector body 9, such as electro-mechanical interconnection with an outer conductor 11 of a coaxial cable 13 and also environmental sealing of the electro-mechanical interconnection, for example by elastomeric sealing gasket(s) 20 seated in a gasket shoulder or annular groove of the coupling body inner diameter. Details of these functions and the associated structures of the coupling body 3 are dependent upon the type of coaxial connector 10 that the stabilizing assembly 1 is applied to.
A jacket grip 15 of rigid material, for example acrylic or polycarbonate plastics, is retained between the coupling body 3 and a stabilizing body 17 coupled to a cable end 7 of the coupling body 3. The jacket grip 15 may be c-shaped, dimensioned for fit within the stabilizing assembly 1 and also to enable insertion of the coaxial cable 13 therethrough during interconnection of coaxial connector 10 and coaxial cable 13. An outer diameter of the jacket grip 15 has a contact surface 19 abutting an inner diameter annular wedge surface 21 of the stabilizing body 17, the wedge surface 21 provided with a taper between a maximum diameter proximate a connector end 5 of the jacket grip 15 and a minimum diameter proximate a cable end 7 of the wedge surface 21.
As the stabilizing body 17 is advanced axially towards the coupling body 3, for example via threads 25 or alternatively an axial compression interference fit, the angled contact surface 19 of the jacket grip 15 contacts the wedge surface 21 of the stabilizing body 17, driving the jacket grip 15 against an inward projecting shoulder 27 of the coupling body 3 and then radially inward against the jacket 29 of the coaxial cable 13. As the inner diameter of the jacket grip 15 engages the jacket 29, a secure stabilizing contact is established, distributed across a width of the jacket grip 15, between the stabilizing assembly 1 and the attached connector body 9. By applying a width of the jacket grip 15, for example at least as wide as a corrugation period of a desired coaxial cable and/or at least twice as wide as a cross-sectional height of the jacket grip 15, chances of coaxial cable deformation resulting from the stabilizing contact are reduced. Because the jacket grip 15 is formed from a rigid non-compressible material and the contacts between the jacket grip 15 and the coupling body 3 and stabilizing body 17 are hard points, once the jacket 29 has deformed, if applicable, from contact therewith, the stabilizing contact is essentially rigid.
The stabilizing contact may be enhanced with respect to a longitudinal axis direction, to also improve the mechanical tear off strength of the interconnection between the coaxial connector 10 and coaxial cable 13, by applying a plurality of inward projecting protrusion(s) 31 to the inner diameter of the jacket grip 15. Further, the inward projecting protrusion(s) 31 may improve an anti-rotation coaxial connector 10 to coaxial cable 13 characteristic of the stabilizing contact.
As best shown in
The coupling body 3, jacket grip 15 and stabilizing body 17 may be cost effectively manufactured via injection molding, for example of polymeric material. The injection molding may be further optimized with respect to materials consumption and reduction of molding defects such as warp and sink by forming areas of the stabilizing body 17 with a plurality of inward extending support fin(s) 37, rather than a conventional solid configuration with significant material thickness areas where material strength requirements of the structure are reduced. Further, to simplify mold design and mold separation mechanics, thread(s) 25 and/or inward/outward projecting retaining lip 33 and/or retention burr 35 may be applied as arc segments rather than continuous annular features. Thereby, upon rotation of the respective mold portion and/or the molded component, axial mold separation is enabled.
In use, the coaxial connector 10 is interconnected with the coaxial cable 13 according to the selected electro-mechanical configuration of the connector body 9 and connector end 5 of the coupling body 3, for example as shown in
Because the stabilizing assembly 1 is separate from the connector body 9, benefits of the stabilizing assembly 1 may be applied to existing connector families with only minimal redesign of the coupling body 3, to obtain the benefits of the stabilizing contact/cable support generated thereby.
The coaxial connector 10 of
Metal scrapings, scratches, chips and/or burrs generated during cable end stripping and/or connector to cable installation have been identified as another potential source of PIM. The present embodiment further reduces PIM by enabling a cable end preparation that avoids metal scrapings, scratches and/or burrs along the inner diameter of the outer conductor 11 by leaving a layer of dielectric and/or adhesive 49 along the inner diameter of the leading edge of the outer conductor 11 (see
Another PIM factor arises from metal to metal scraping between the spring contact 43, here demonstrated as an annular coil spring, and the connector body 9 and/or outer diameter of the outer conductor 11 if the spring contact 43 rotates with the slip ring 45 as the connector coupling body 39 is rotated during tightening to obtain the electro-mechanical interconnection with the outer diameter of the outer conductor 11. To encourage the spring contact 43 to seat against the outer diameter of the outer conductor 11 and against the connector body 9 with minimal rotation, the contact area 51 between the slip ring 45 and the spring contact 43 is provided with a reduced friction surface by forming the contact area 51 of the slip ring 45 with an arc radius complementary to the dimensions of the spring contact 43 as clamping force is applied. The inventor's analysis of assembled coil springs indicates that the spring contact 43 is progressively deformed as the clamp force is applied during interconnection. Therefore, rather than forming the contact area 51 of the slip ring 45 with the spring contact 43 as an arc section of a circle, for example as shown in
In the outer conductor outer diameter current path configuration of the current embodiment, the electrical current path passes from the outer conductor 11 through the spring contact 43 to the connector body 9. Where the contact area 51 of the slip ring 45 is an oval arc section, a smooth complementary contact between the spring contact 43 and the slip ring 45 is increased, resulting in lower relative friction between these surfaces than arises between the smaller and/or sharper edge contact area 53 of the connector body 9 as the spring contact 43 is deformed during compression. That is, the contact area 51 of the slip ring 45 against the spring contact 43 (as deformed by compression) has a greater surface area than an edge contact area 53 of the connector body 9 against the spring contact 43. As the connector coupling body 39 is rotated, the slip ring 45 can rotate with respect to the spring contact 43 but the spring contact 43 will tend to be rotationally locked with respect to the higher friction, smaller edge contact area 53 of the connector body 9. Thereby, the potential for PIM generating scraping at these current path contact points during installation may be reduced.
Because the electrical current path to the connector body 9 from outer diameter of the outer conductor is via the spring contact 43, the contact area 41 supporting the inner diameter of the outer conductor 11 is not required to be a conductive surface. In a further embodiment, for example as shown in
For further ease of installation, as shown for example in
One skilled in the art will appreciate that the stabilizing assembly 1 and several PIM reduction features of the disclosed connector arrangements enables a coaxial connector with improved electrical performance and both cost and installation efficiencies.
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.
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.
Number | Date | Country | |
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Parent | 12795013 | Jun 2010 | US |
Child | 13433635 | US |