1. Field of the Invention
The present invention generally relates to coaxial cable connectors. More specifically, the present invention relates to a coaxial cable connector with ease of installation features that is installable with reduced connector specific tooling requirements.
2. Description of the Prior Art
Coaxial cable connectors are used, for example, in communication systems requiring a high level of reliability and precision. A connector that is poorly installed may damage equipment, significantly degrade system performance and or lead to premature system failure. Therefore, prior connectors typically include extensive installation instructions that require costly specialized tools specific to each connector.
One specialized tool for connectors is the jacket stripper. The jacket stripper is used to accurately strip away outer sheathing from the coaxial cable to expose a specified length of outer conductor for electrical contact with the desired surfaces of the connector. If the amount of outer sheathing removed is short, long or non-uniform, the electrical connection and or the environmental seal of the connector to the cable may be degraded.
Connectors may be used in confined spaces, for example among banks of cables with minimal spacing between them. Confined spaces increase the difficulty of proper connector installation and or interconnection by increasing the time required to make repeated small turns allowed by the confined space when threading the connectors by hand and or with the aid of a wrench. Also, connectors may be installed in exposed locations such as the top of radio towers where installation personnel may be less inclined to properly follow time-consuming installation procedures.
Threaded connections on and between connectors are typically tightened using wrenches having the potential for large moment arm force generation that may damage the connector and or associated cable(s). Therefore, use of a torque wrench with a torque setting specific to each connector is often specified by the prior connector installation instructions. Applying the proper torque, for example 15–20 lb-inches, to threaded connections ensures correct electrical interconnection and prevents application of excessive force that may deform or otherwise damage threads, seals and or the relatively soft metal(s) of the cable(s). The torque wrench is a costly and easily damaged tool that the installation personnel may not always have on hand or bother to use correctly, if at all.
Competition in the coaxial cable connector market has focused attention on minimization of overall costs, including 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 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 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.
As shown in
A cable stripping feature of the connector 1 is demonstrated by
A slot 40 formed in the rear clamp nut 10 has a cutting edge 45 at the end of a helical step 47 between the first inner diameter and the second inner diameter. When the rear clamp nut 10 is placed over the end of the cable 5, the sheath 20 bottoms against the helical step and the cutting edge 45. Rotating the rear clamp nut 10 about the cable 5 drives the sheath 20 against the cutting edge 45 which cuts and separates the sheath 20 from the outer conductor 15. The cut portion of the sheath 20 exits through the slot 40 as the rear clamp nut 10 is advanced over the cable 5. The sheath 20 is trimmed to the correct length, for example, when the outer conductor 15 reaches the connection end of the rear clamp nut 10.
The rear clamp nut 10 may be attached to the connector body 50 via threads 25 shown in detail on
One or more over-tightening protection assembly(s) 24 of the connector 1 prevents damage to the connector body 50, rear clamp nut 10 (if present), threads, seals and or the relatively soft metal(s) of the cable(s). A separate over-tightening protection assembly 24 may be applied to operate with respect to the threads 25 and the connector threads 56, each with a separate desired torque rating. The over-tightening protection assembly 24 is explained with the aid of a simplified version of connector 1, as shown in
Rotation of the connector body 50 is coupled, within a selected torque range, to the inner coupling sleeve 60 by a first ring and a second ring having complementary protrusions. To describe the first and second rings interaction in detail, a specific embodiment wherein the first ring is a finger ring 65, as shown for example in
The finger ring 65 and the ramp ring 70 may be located coaxially within a groove 52 formed in the connector body 50. The finger ring 65 may be keyed to the connector body 50 by a plurality of first ring tab(s) 75 distributed around the inner diameter of the groove 52 which interlock with corresponding finger ring slot(s) 76 in the finger ring 65. Similarly, the ramp ring 70 may be keyed to the inner coupling sleeve 60 by a plurality of inward projecting second ring tabs 77 that couple with inner coupling sleeve slot(s) 78 formed in, for example, a cable end of the inner coupling sleeve 60. Finger(s) 80 projecting inward from the finger ring 65 engage the ramp(s) 85 extending outwards from the ramp ring 70.
Rotation of the connector body 50 is transmitted to the inner coupling sleeve 60 for threading of the connector threads 56 until a predetermined torque value is reached whereupon the finger(s) 80 of the finger ring 65 and or the ramp(s) 85 of the ramp ring 70 momentarily deforms and slips past the ramp ring 70 or vice versa, preventing application of out of range torque levels to the inner coupling sleeve 60 and thereby to the connector threads 56, gaskets and or the relatively soft metal(s) of the cable(s). During reverse rotation, the finger(s) 80 impact a step side of the ramp(s) 85 having an increased angle ensuring that increased torque levels sufficient to enable unthreading of the connector 1 may be applied.
The torque value at which the finger ring 65 slips past the ramp ring 70 may be adjusted by selecting materials with desired bending/deformation characteristics; adjusting the angles of the mating surfaces of the finger(s) 80 and or ramp(s) 85; and or modifying the thickness of the selected material(s). For example, the finger ring 65 may be formed by a process comprising metal stamping, bending and ring rolling and the ramp ring 70 may be injection molded of a plastic such as nylon. Similarly, the positions of the finger and ramp ring pairs may be switched and or either or both of the first and second rings replaced with other forms of complementary protrusions and or interlocking structures of which at least one of a complementary pair will deform and release the connector body 50 to inner coupling sleeve 60 interlock when the applied rotation torque reaches a desired threshold level. For example, interlocking protrusions, bumps, arches and or leaf springs may be used with an equivalent effect according to the invention.
One skilled in the art will appreciate that the cable end of the connector 1 may be adapted to mate with the dimensions and configuration of a specific coaxial cable 5, for example a coaxial cable with annular or helical corrugations in the inner and or outer conductors 27, 15. Further, the connector end of the connector 1 may be adapted to mate according to male and or female embodiments of a proprietary interface or one of the standard connector types, for example BNC, Type-N or DIN.
The present invention provides coaxial connectors with ease of installation features and reduces specialized installation tool requirements. The sheath stripping cutting edge slot eliminates the need for a dedicated sheath stripping tool and strips the sheath to the correct outer conductor exposure during connector assembly without requiring a separate stripping step. Interleaved threads allow the connector to be installed with a significantly reduced threading requirement. Also, protection from damaging excess torque application during connector installation and elimination of the need for torque wrenches is built into the connector.
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.
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Number | Date | Country | |
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20050017828 A1 | Jan 2005 | US |