This invention relates to RF connectors. Proper torque must be applied to a mated pair of coaxial connectors to ensure consistent and repeatable tests of coaxial devices under test and this is especially true in the case of calibration of any test instrument such as network analyzers or other test instrumentation having coaxial test ports.
The sex of coaxial connectors is conventionally identified by the configuration of the inner conductor center contacts. If a connector has a pin then it is considered a male connector; if it has a socket then it is considered a female connector. The outer conductor of the female connector has male threads and the male connector has a connector nut with female threads, configured to engage the male threads on the female connector body. This rule will almost always apply except in the case where the connectors are hermaphrodite or a special configuration where the sex is reversed to accommodate polarization.
Singular solid plastic or metal spin rings have been used, with a female hex feature in the middle, corresponding to the hex nut size, a typical size being approximately 5/16 inch thick and having an outside diameter of ¾ inch approximate, with external features (bumps, hex, knurl, etc.) to assist in gripping or rotating to loosen or tighten the male coaxial connector to a mating female connector. Some of these spin rings have a slot to allow clearance for a 0.086 or 0.141 diameter coaxial cable when the spin ring is introduced from the rear. This device does not apply a pre-set torque to the mated pair of connectors when coupled and tightened. By its nature, the device does not provide electrical measurement repeatability from mating to mating due to the inconsistent pressure applied at the mating interface plane of the connectors.
Commercially available torque wrenches have an open end wrench of the appropriate size to mate with the hex nut on the applicable connector and a handle typically 5-6 inches long and has a pre-set torque value. This handle slips and dis-engages when the pre-set torque value is reached, ensuring that the connected pair of connectors will not exceed the torque specifications for the applicable mated pair.
Typically a spin ring is left on the connector during test and cannot be removed to allow the use of a torque wrench to achieve the torque specification. Conversely the spin ring (in most configurations of connectors) cannot be used if it is necessary to use the torque wrench to apply torque to the coupled connectors.
In the case of the hex coupling nuts that are permanently fastened to the male or hermaphrodite (sexless) coaxial connectors there are no provisions built into the nuts to apply the correct torque to the coupled pair of connectors.
Features and advantages of the disclosure will readily be appreciated by persons skilled in the art from the following detailed description when read in conjunction with the drawing wherein:
In the following detailed description and in the several figures of the drawing, like elements are identified with like reference numerals. The figures are not to scale, and relative feature sizes may be exaggerated for illustrative purposes.
In an exemplary embodiment, a torque ring or nut system is used on or with RF and microwave male/female paired coaxial connectors, to apply a pre-set torque value to the mated coaxial connector pair. This results in significant time savings in mating and applying torque to a pair of connectors. In an exemplary embodiment, the torque ring is employed on the male coaxial connector; the mating female connector may be fixed to a device or instrument, and can be held securely by hand or by mechanical devices. An exemplary embodiment of the torque ring (“TR”) system is contemplated as a removable torque system, which can be removed from the connector after use, and an exemplary embodiment of the torque nut (“TN”) system is contemplated as a non-removable system, integrated with the connector structure.
Exemplary applications include 1.0, 1.85, 2.4, 2.92 and 3.5 mm connectors having a 5/16 inch hexagonal coupling nut, as well as any connector utilizing a hex nut or having a coupling nut to assist in tightening or torqueing one connector to another mating connector for the purposes of test and calibration, preferably by use of finger pressure only. Exemplary embodiments of both the TR and TN devices can be mechanically calibrated to a pre-set torque value using conventional torque calibration equipment and suitable adapters.
An exemplary embodiment of the invention includes an outer ring structure and an inner ring structure.
The torque ring system 50, as further illustrated in
The inner ring structure 60 has a female configuration opening 62 formed through the center (with or without a stop surface to control depth of engagement), the size to conform closely to the connector size used on the applicable coaxial connector coupling nut to be threaded and torqued to specification. Typical connector configurations are hexagonal (“hex”), but the torque system may be adapted to other connector configurations as well. The opening 62 allows the connector nut to be fitted within the opening for use.
An exemplary embodiment of the inner ring structure 60 has a continuous groove 64 on its outer diameter having a depth suitable to receive retaining pins or set screws 72 into the groove introduced from the outer ring structure 70. The pins 72 are of a suitable diameter and quantity to allow smooth rotation of both ring structures without binding while at the same time allowing minimum end play between the inner and outer ring structures 60 and 70, i.e. the axial movement between the outer ring 70 and inner ring 60. The groove 64 has a bottom surface 64A.
The retaining pins 72 in an exemplary embodiment can be, for example, dog-point setscrews engaging a threaded bore in the outer ring.
An exemplary embodiment of the inner ring 60 has at least one indentation 66 forming a ramp surface, and in some cases, two or more symmetrical indentations or sets of indentations located on groove bottom surface 64A.
The indentations 66A, 66B, 66C in the exemplary embodiment of
In an exemplary embodiment, maximum torque is reached when the ball travels to the edge 66A1 of the long flat surface 66A of the indentation 66 and transitions to the surface 64A of the inner ring groove or race 64 as the outer ring 70 is rotated clockwise over the fixed or stationary inner ring 60. When the ball 76 transitions to the groove surface 64A, maximum torque will be achieved and cannot be exceeded even as the outer ring continues through 360 degrees of continuous clockwise rotation. As the outer ring is rotated clockwise, the pre-loaded ball 76 will drop into the next indentation 66, with the ball being adjacent to the short vertical wall 66B of that indentation. When rotation of the outer ring is reversed to counter-clockwise motion, a higher torque value is presented by the ball trying to climb over the vertical face or short stop surface 66B of the indentation. This increased torque is then applied to the inner ring 60 and transmitted to the connector hex nut 10, allowing the user to overcome the original torque applied (in a clockwise motion), and therefore allowing the mated pair of connectors to be unthreaded and decoupled.
The outer circumferential surface of the outer ring 70 may have a variety of configurations, all designed to provide a non slip comfortable grip for the user as well as providing a mechanical advantage to amplify the inner ring rotation assisting it to reach its maximum torque value. For example,
An exemplary embodiment of the outer ring 70 provides one or more threaded holes to receive the balls with springs on set screws, one or more, and in an exemplary embodiment, three tapped or press fit holes to accept the retaining pins. The outer ring may also be provided with one or more clearance or tapped holes to accept an auxiliary rod 90 (
Tests have shown that by using rotational force it is possible to hand tighten a 0.75 inch diameter spin ring and apply 8 in/lbs. of torque. While this is possible it does require considerable hand strength to do so. By increasing the outer diameter of the ring to 1.0 inch, for example, the application of the 8 In/lbs. of torque becomes much easier and appears to be a practical solution for someone of average hand strength to apply intermittently as required by tests of this nature. Therefore, an outer diameter surface or peak diameter of an outer ring having knurls, spokes, ridges or variable shape indentations are suitable for this application.
The torque system can be calibrated prior to use to set the amount of maximum torque applied by the system. An exemplary calibration technique is analogous to a technique used to calibrate torque wrenches. A torque meter such as a Mountz Torque Tester (e.g. model LTT-2100) may be employed with suitable coaxial adapters to mate the torque ring or torque nut system to the torque tester. For example, for the torque ring system, the assembled torque ring may be inserted onto the hex shaft of the adapter mounted on the torque tester. For the torque nut system, the torque nut may be screwed onto the male threads on the adapter mounted on the torque tester. The outer ring of the system is rotated clockwise to determine the starting torque value. When the maximum torque is reached, the outer ring will continue to rotate until the ball(s) drop into the next indentation. The torque ring or torque nut will not be capable of applying any additional torque without adjusting the setscrew(s) such as 72A, 72B and 72C. To adjust the maximum torque, the setscrew(s) may be evenly turned clockwise to increase the pressure between the outer ring 70 and inner ring 60, thus increasing the radial torque that the torque ring or torque nut will apply to the torque tester when rotated clockwise. The measured torque value may be recorded, and the process of evenly turning the setscrew(s) may be repeated until the desired maximum torque pressure is achieved.
In an exemplary embodiment, the calibrated torque value may be in the range of 5 to 25 inch pounds with an accuracy of +/5%.
An alternate embodiment of the torque ring system 50′ is illustrated in
An exemplary embodiment of a torque nut (TN) system 150 is illustrated in
First referring to the isometric view of
Referring now to
The inner ring can be fabricated of a metallic material for strength and wear characteristics, but does not have to be conductive. The outer ring can be plastic, metal or composite, with the materials selected to be suitable to provide excellent long term wear characteristics.
The amount of torque applied by the use to the TR or TN system can be amplified by use of swing out pawls, as illustrated in
Although the foregoing has been a description and illustration of specific embodiments of the subject matter, various modifications and changes thereto can be made by persons skilled in the art without departing from the scope and spirit of the invention.
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Number | Date | Country | |
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20130125716 A1 | May 2013 | US |