Abstract:
A product and method for preventing a connector from rotating when a mating connector is attached to, or detached from, the connector. When a nut on the connector is tightened, a washer is compressed in a groove in a panel to which the connector is attached. Edges on the outer perimeter of the washer press against the edges of the groove, thus preventing the washer from rotating in relation to the panel having the connector. A portion of the washer&#39;s cutout presses against flat regions on the connector and, in conjunction with the groove in the panel, prevent the connector from rotating when attaching or detaching cables.

Description:
FIELD OF THE INVENTION 
     This invention relates to locking mechanisms for connectors and, more particularly, to a mechanism to prevent rotation of a connector during connect and disconnect operations. 
     BACKGROUND OF THE INVENTION 
     Many connectors, such as SMA or SMC connectors, attach to mating connectors by means of threads or other means that require application of rotational force during connection and disconnection. Unless prevented in some manner, a connector will rotate due to the rotational force exerted when connecting or disconnecting mating connectors. 
     A persistent problem in the telecommunications industry is base station connectors that rotate when mating connectors are disconnected. These base station connectors extend through a wall (or panel) of the base station enclosure and allow an external cable to be electrically connected to the base station&#39;s internal electronics. FIG. 1, discussed below, shows a typical example of a connector  100  extending through a panel  120  of a base station. Base station connectors mate with another connector (a mating connector) that usually is attached to a coaxial cable of some sort. The base station connectors often have a soldered electrical connection on the internal side of the base station enclosure. Even a few degrees of rotation can be enough to break solder joints so it is very important to prevent the base station connector from rotating. 
     FIG. 1 shows a prior art method of preventing a connector  100  from rotating during connection or disconnection of mating connectors. Connector  100  has threads at one end for screwing into a threaded hole in panel  120  and at the other end for attaching a nut  110 . Nut  110  is then screwed down tight against panel  120  to prevent connector  100  from rotating. This method is commonly used but does not prevent rotation very well. 
     FIG. 2 shows a prior art method of preventing a connector  200  from rotating during connection or disconnection of mating connectors. Connector  200  has a rectangular flange  210  with screw holes  230  in each corner. Connector  200  inserts into a hole in panel  120 . It is held in place by screws inserted in each of the screw holes  230 . This method works well but requires drilling and thread tapping of four additional holes. Therefore this method is expensive, difficult to manufacture, and requires extra steps to attach connector  200  to panel  120 . 
     FIG. 3 shows a prior art method of preventing a connector  300  from rotating during connection or disconnection of mating connectors. Connector  300  has a flange  310 . When connector  300  is screwed into a threaded hole in panel  120 , flange  310  compresses O-ring  330  against panel  120 . Under ideal conditions, O-ring  330  provides enough frictional resistance to rotation that mating connectors can be connected or disconnected without causing connector  300  to rotate. When exposed to the elements in the field, the connector oxidizes. The oxidation causes the connector to bind when joined with its mate, requiring application of greater rotational connect/disconnect force than the O-ring  330  can resist. Thus this method does not prevent rotation under commonly encountered field conditions. 
     Additional general background, which helps to show the knowledge of those skilled in the art regarding the system context, and of variations and options for implementations, may be found in Catalog Number 82074 version 5-98 from AMP Incorporated, all of which is hereby incorporated by reference. 
     SUMMARY OF THE INVENTION 
     A lock washer and method for preventing a connector from rotating when mating connectors are attached or detached. In the presently preferred embodiment, the disclosed connector locking mechanism incorporates an innovative lock washer that, in combination with a groove in a panel holding the connector, prevents rotation of the connector when a mating connector is twisted on or off. 
     In the presently preferred embodiment, a connector that is attached to a panel is prevented from rotating by the use of an innovative lock washer that fits in a groove in the panel. The lock washer has a keyhole-shaped cutout. Part of the cutout has approximately parallel edges. Another part of the cutout allows the lock washer to fit over the larger perimeter (meaning without flat regions) portion of connector. After the lock washer is on the connector, the lock washer slides so that the approximately parallel edges of the cutout are aligned over flat regions on the connector. Then a nut is screwed onto the connector, compressing the approximately parallel edges of the lock washer cutout against the flat regions on the connector. The groove in the panel prevents the lock washer (and thus the connector) from rotating during attachment/detachment of mating connectors. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The disclosed inventions will be described with reference to the accompanying drawings, which show important sample embodiments of the invention and which are incorporated in the specification hereof by reference, wherein: 
     FIG. 1 depicts a prior art system for preventing connector rotation. 
     FIG. 2 depicts a prior art system for preventing connector rotation. 
     FIG. 3 depicts a prior art system for preventing connector rotation. 
     FIG. 4 depicts a top view of the presently preferred embodiment of the disclosed innovative connector system. 
     FIG. 5 depicts a cut-away side view of the presently preferred embodiment of the disclosed innovative connector system. 
     FIG. 6A depicts a top view of the presently preferred embodiment of the disclosed innovative lock washer. 
     FIG. 6B depicts a side view of the presently preferred embodiment of the closed innovative lock washer. 
     FIG. 7A depicts a side view of a connector having flat regions. 
     FIG. 7B depicts an end view of a connector having flat regions. 
     FIG. 7C depicts top view of a connector having flat regions. 
     FIG. 8A shows an alternate shape for the disclosed lock washer. 
     FIG. 8B shows an alternate shape for the disclosed lock washer. 
     FIG. 8C shows an alternate shape for the disclosed lock washer. 
     FIG. 8D shows an alternate shape for the disclosed lock washer. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The numerous innovative teachings of the present application will be described with particular reference to the presently preferred embodiment. However, it should be understood that this class of embodiments provides only a few examples of the many advantageous uses of the innovative teachings herein. In general, statements made in the specification of the present application do not necessarily delimit any of the various claimed inventions. Moreover, some statements may apply to some inventive features but not to others. 
     FIGS. 4 and 5 show a top view and cut-away side view (taken along line AA), respectively, of the presently preferred embodiment of the disclosed innovations. A first end  490  of an SMA connector  440  extends perpendicularly from a panel  460 . A groove  470  is manufactured into panel  460 . A washer  400  fits over the end  490  of connector  440  and into groove  470 . Washer  400  has a keyhole-shaped cutout  420  with approximately parallel edges  430 . A portion  425  of cutout  420  is large enough to allow washer  400  to slip over end  490  of connector  440 . After washer  400  is placed on connector  440 , washer  400  slides so that the approximately parallel edges  430  of the keyhole-shaped cutout  420  are aligned with flat regions  530  on connector  440 . Note that FIG. 4 shows the “post-slide” alignment in which approximately parallel edges  430  align with flat regions  530 . After washer  400  is in place, a nut  450  screws onto connector  440 . As nut  450  presses against washer  400 , the approximately parallel edges  430  are forced closer together by the deformation of washer  400 . Thus approximately parallel edges  430  of cutout  420  are compressed tightly against flat regions  530  of connector  440 . 
     Threads  500  at end  540  hold connector  400  to panel  460 . A wire or cable (not shown) is connected at solder connection pin  510 . Washer  400  fits into groove  470 . Edges  480  of groove  470  restrict movement of washer  400 . As nut  450  is tightened onto connector  440 , the approximately parallel sides  430  of cutout  420  in washer  400  are compressed against the flat regions  530  of connector  440  and the outer perimeter of washer  400  is compressed against edges  480  of groove  470 . In the presently preferred embodiment, the concave shape of washer  400  helps push approximately parallel sides  430  of cutout  420  tight against flat regions  530  of connector  440 . The concave shape also helps push the outer perimeter of washer  400  against edges  480  of groove  470 . Thus the concave shape has advantages over a flat shape: the edges of the cutout can be tightened against the flat regions on the connector and the washer perimeter can be tightened against edges of the groove. These advantages lead to a further advantage: increased tolerance for dimensional variations in manufacturing. A flat washer must precisely match the dimensions of the connector and the groove because a solder connection has very small tolerance for rotation. This would require that a flat washer be custom manufactured to match a particular connector and groove, an economically unfeasible alternative. A concave washer avoids this problem due to its spring-like properties. 
     FIG. 6A shows a top view of the presently preferred embodiment of washer  400 . Approximately parallel flat edges  410  are on the outer perimeter of washer  400 . A keyhole shaped cutout  420 , having approximately parallel edges  430 , is disposed within the outer perimeter of washer  400 . Cutout  420  also a portion  425  that allows the washer to slip over end  490  of connector  440 . 
     FIG. 6B shows a side view of the presently preferred embodiment of washer  400 . Due to the concave surface, the distance between the approximately parallel edges  430  will decrease when the washer is compressed. Rotation is prevented because movement of outer perimeter edges  410  is restricted (by edges  480  of groove  470  as shown in FIG.  4 ). 
     For clarity, FIGS.  7 A-C show a side view, end view, and top view of connector  440 , respectively. Flat regions  530  can more easily be seen in FIGS.  7 A-C than in FIGS. 4 and 5. FIG. 7B shows an end view from end  490 . 
     FIG. 8A shows an alternative washer embodiment. Washer  800  is similar to washer  400  except that the outer perimeter  810  is circular and does not have flat edges. As in the presently preferred embodiment, a keyhole-shaped cutout  820  with approximately parallel edges  830  (and a portion  825  for slipping over an end of a connector) is disposed within the outer perimeter of washer  800 . 
     FIG. 8B shows an alternative washer embodiment. Washer  850  is similar to washer  400  except that it is octagonal. As in the presently preferred embodiment, a keyhole-shaped cutout  870  with approximately parallel edges  880  (and a portion  875  for slipping over an end of a connector) is disposed within the outer perimeter of washer  800 . 
     FIG. 8C shows an alternative washer embodiment. Washer  900  is rectangular in shape and is folded along the centerline. A keyhole-shaped cutout  920  has approximately parallel edges  910  and a portion  925  for slipping over an end of a connector. The keyhole-shaped cutout  920  is disposed along the centerline  940 . When concave washer  900  is compressed, edges  930  are forced against edges of a groove on a panel. 
     FIG. 8D shows an alternative washer embodiment. The outer perimeter of washer  950  has flat edges  980  similar to the presently preferred embodiment. A slot-shaped cutout  960  has approximately parallel edges  970 . Unlike the cutouts of the previously disclosed embodiments, the slot-shaped cutout  960  opens to the outside perimeter. This allows washer  950  to be placed onto flat regions (such as regions  530  shown in FIG. 7A) on a connector without having to fit over the end of the connector. When concave washer  950  is compressed, edges  980  are forced against edges of a groove on a panel. 
     As will be recognized by those skilled in the art, the innovative concepts described in the present application can be modified and varied over a tremendous range of applications, and accordingly the scope of patented subject matter is not limited by any of the specific exemplary teachings given. 
     For example, the washer cutout could be any suitable shape and is not limited to a keyhole shape. 
     As another example, the washer shown in FIG. 8B could have another polygonal shape with more or fewer flat edges on the outer perimeter. 
     As another example, the washer  400  does not have to be concave. It may be flat, although more precise machining is required when using a flat washer. 
     As another example, connector  440  could extend from panel  460  at any suitable angle, not just perpendicularly. 
     As another example, the groove in the panel could be any suitable structure for preventing the lock washer from rotating, including grooves with different geometries than those disclosed above. A suitable structure may include two smaller parallel grooves into which only the edges of the concave washer fit. Another suitable structure may be a groove that is approximately the same size as the washer, such that the approximately parallel edges of the cutout must be aligned with the flat regions of the connector before the washer fits into the groove. Another suitable structure may be raised ridges (instead of a groove) that prevent the lock washer from rotating. 
     As another example, the parallel edges of the cutout do not have to be parallel. Any suitable geometry that will grip a flat region of the connector can be used. A suitable geometry of cutout may have sawtooth-like edges. Another suitable geometry may only use one flat edge in the cutout to mate with a flat region on the connector.