Abstract:
An anti-decoupling device for use in preventing undesired rotation of a spin coupling of, for example, a two-part electrical connector, is disclosed. The anti-decoupling device can form part of a new connector, or can be used to retrofit existing connectors without having to modify the connector. In some embodiments, the anti-decoupling device comprises a base and two prongs that extend in a generally axial direction relative to the base. Blades that depend from the prongs extend into channels within the knurled side-edge of the spin coupling. The blades prevent inadvertent rotation of the spin coupling.

Description:
FIELD OF THE INVENTION 
   The present invention relates to connectors, and, more particularly, to a device that prevents a spin coupling from loosening. 
   BACKGROUND OF THE INVENTION 
   It is common practice to use a two-part connector to join electrical conductors. In such connectors, a first group of electrical conductors terminate in one of the connector “halves” and a second group of electrical conductors terminate in the other of the connector halves. To establish electrical connection between the two groups of electrical conductors, the two connector halves are joined. 
   The two halves of the connector are typically held together by a nut, typically referred to as a “spin coupling,” a “coupling nut,” or a “locking ring.” The spin coupling is usually permanently attached to one of the connector halves at the time of initial assembly. In some embodiments, the spin coupling is internally threaded and is rotated to engage mating threads on the other connector half. 
   The spin coupling is the primary means of maintaining the integrity of the mechanical and electrical interfaces of the two-part connector. As a consequence, after the two connector halves are joined, it is very important that the spin coupling does not rotate in such a way as to loosen. Inadvertent rotation can result, for example, from shock, vibration, G-loading, etc. 
   Many anti-decoupling mechanisms have been proposed to prevent inadvertent rotation of a connector spin coupling. But few if any of these mechanisms can be used to retrofit standard connectors. Rather, in most cases, the mechanisms are an integral part of what is effectively a new connector design. In the few cases that the mechanisms can be used to retrofit a standard connector, the retrofit requires modifying the standard connector, such as by machining it, to add notches, holes, and the like. 
   The ability to retrofit a standard connector with an anti-decoupling device without modifying the connector would be very beneficial. 
   SUMMARY OF THE INVENTION 
   The present invention provides a way to prevent a spin coupling from loosening without some of the costs and disadvantages of the prior art. 
   In accordance with the illustrative embodiment of the present invention, an anti-decoupling device is used to prevent undesired rotation of a spin coupling of, for example, a two-part electrical connector. Among other benefits of the anti-decoupling device disclosed herein, it can be used to retrofit existing connectors without having to modify the connector. Furthermore, in some embodiments, the anti-decoupling device is able to retrofit an in-field connector without having to disassemble the connector. 
   In accordance with the illustrative embodiment, the anti-decoupling device comprises a base and two prongs that extend in a generally axial (as opposed to radial) direction relative to the base. 
   In use, the base of the anti-decoupling device couples to a fitting (e.g., a hex nut, etc.) that attaches one half of the electrical connector to, for example, a bulkhead, an electrical box, etc. The base has a large, centrally-located opening (i.e., like a washer). In use, one of the connector portions is received by this opening. 
   The prongs of the anti-decoupling device are diametrically opposed to one another on the base. The prongs extend sufficiently far in the axial direction so that the free end of each prong aligns with the spin coupling (when the spin coupling is in a locking positioning for joining the two connector halves). 
   In the illustrative embodiment, each prong is partially folded about its longitudinal midline, thereby forming a “v,” at least proximal to the free end thereof. Due to this fold along the longitudinal midline, the side edges (hereinafter “blades”) of each prong extend in the radial (as opposed to longitudinal) direction, toward the knurled edge of the spin coupling. The knurling (i.e., a series of successive ridges and channels) facilitates manual tightening of the spin coupling. 
   The prongs are appropriately distanced from the spin coupling so that contact between the channels of the spin coupling and the blades results in an “outward-” directed force on the free-end of the prongs. That is, the force urges the free-end of the prongs away from the spin coupling. Since the prongs are rigidly attached to the base, this outward force effectively spring loads the cantilevered prongs so that the v-shaped free-end of each prong is biased toward the spin coupling. 
   Due to the v-shape of the prongs, the two blades on each prong extend in different directions. That is, relative to a line that bisects the “v,” one blade extends toward the “left” and the other blade extends toward the “right.” The blade that extends to the left will tend to prevent inadvertent rotation of the spin coupling in the counter-clockwise direction and the prong that extends to the right will tend to prevent inadvertent rotation in clockwise direction. Yet, the spin coupling can be manually forced, such that it does not have to be removed to decouple the connector. 
   In this manner, and unlike most prior-art anti-decoupling devices, the present anti-decoupling device interfaces with the exterior of conventional connectors and with existing features thereof (i.e., the knurled edge of the spin coupling). And by virtue of a “clip-on” or “screw-on” functionality of the base, the anti-decoupling devices disclosed herein are able to retrofit virtually any two-part connector. 
   The utility of the present anti-decoupling devices for retrofitting existing connectors is manifest. In some further embodiments, the present invention provides an improved connector that includes the present anti-decoupling device. In other words, an aspect of the present invention is a new two-part connector that incorporates, at the time of manufacture, an anti-decoupling device as disclosed herein. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  depicts a conventional, two-part electrical connector having a spin coupling, wherein the electrical connector is in a disconnected state. 
       FIG. 1B  depicts the conventional, two-part electrical connector of  FIG. 1 , wherein the two parts of the connector are joined. 
       FIG. 2A  depicts an anti-decoupling device in accordance with the illustrative embodiment of the present invention. 
       FIG. 2B  depicts an alternative embodiment of an anti-decoupling device, wherein the anti-decoupling device comprises two, separable parts. 
       FIG. 3  depicts the anti-decoupling device of  FIG. 2A  used in conjunction with the two-part connector of  FIGS. 1A and 1B  to prevent inadvertent rotation of the spin coupling. 
       FIG. 4  depicts a representation of the manner in which a “spring” bias is developed in the prongs of the anti-decoupling device. 
       FIG. 5  depicts a close up of the interaction between a spin coupling and the anti-decoupling device of  FIG. 2A  or  2 B. 
       FIG. 6A  depicts a conventional mil type circular connector. 
       FIG. 6B  depicts an embodiment of an anti-decoupling device for use in conjunction with the connector of  FIG. 6A , wherein the anti-decoupling device is adapted to clip on to a flange that attaches the connector to a bulkhead. 
       FIG. 6C  depicts an embodiment of an anti-decoupling device for use in conjunction with the connector of  FIG. 6A , wherein the anti-decoupling device is adapted for screw mounting to the flange that attaches the connector to the bulkhead. 
   

   DETAILED DESCRIPTION 
     FIGS. 1A and 1B  depict, via perspective views, the salient elements of a conventional, two-part electrical connector  100 .  FIG. 1A  depicts connector  100  in a disconnected state and  FIG. 1B  depicts connector  100  in a connected state. 
   As depicted in  FIG. 1A , a female connector portion  102  of connector  100  includes body  104 , cable strain relief  108 , sheath  110 , and spin coupling  112 , interrelated as shown. Electrical conductors  111  are disposed in sheath  110  and terminate, at body  104 , in sockets (not depicted). 
   Male connector portion  120  of connector  100  includes body  122 , screw threads  124 , contact pins  126 , electrical conductors  128 , and hex mount  130 , interrelated as shown. Pins  126  are electrically connected to conductors  128 . 
   To electrically connect electrical conductors  128  to electrical conductors  111 , female connector portion  102  and male connector portion  120  are pushed together into mating engagement. In this state, pins  126  are received by the sockets within body  104  of female connector portion  102 . It will be understood that the association of some of the features with one or the other of the “female” connector or the “male” connector is somewhat arbitrary and interchangeable. 
   It is imperative that, once connected, male connector portion  120  and female connector portion  102  do not disengage or otherwise loosen to the point that the integrity of the electrical coupling between the two sets of conductors is threatened. To that end, spin coupling  112 , which is internally threaded, is “screwed” onto threads  124  of male connector portion  120 . Spin coupling  112  includes knurled edge  114 . The “knurls” comprise alternating “ridges” and “channels” that facilitate manually tightening spin coupling  112 . The mated connector appears in  FIG. 1B . 
   Experience has shown that vibration, shock, G-forces, and other physical disturbances are capable of loosening spin coupling  112 . Consequently, it is advisable to provide two-part connectors that incorporate a spin coupling with an anti-decoupling device. 
     FIG. 2A  depicts anti-decoupling device  230 A in accordance with the illustrative embodiment of the present invention. As depicted in  FIG. 2A , anti-decoupling device  230 A includes base  232 A and prongs  238 , interrelated as shown. Base  232 A and prongs  238  may suitably be formed of metal, plastic, or the like. 
   Base  232 A includes a physical adaptation that enables it to couple to a connector. In the illustrative embodiment, this physical adaptation is clip  234 . The clip enables anti-decoupling device  230 A to couple to any feature that has substantially flat sides, such as a hex nut, a square or rectangular flange, etc. In the illustrative embodiment, base  232 A includes two clips  234  that are diametrically opposed to one another about base  232 A. 
   Base  232 A also incorporates large central opening  236 . This opening accommodates the body of the connector (half) to which anti-decoupling device  230 A will be attached (see, e.g.,  FIG. 3 ). 
   As depicted in  FIG. 2A , prongs  238  extend substantially parallel to central axis A-A, which, for reference herein, is described as extending in the “axial” direction or, in some cases, as a “longitudinal” direction. In some embodiments, prongs  238  deviate slightly “inward” of parallel (i.e., slightly toward axis A-A) for reasons that will become clear later in this specification. 
   In the illustrative embodiment, prongs  238  are diametrically opposed to one another on base  232 A. Each prong  238  extends a distance, D, in the axial direction that will position its free end  242  in alignment with the spin coupling of a joined and locked two-part part connector. This distance will vary for different connectors; as a consequence, distance D will be different for various versions of the present anti-decoupling device. 
   In the illustrative embodiment, each prong  238  is partially folded about its longitudinal midline  240 , thereby bending the prong into the shape of a “v.” This fold creates blades  244 A and  244 B, which, due to the fold, extend in a lateral or radial direction toward the central axis A-A. 
     FIG. 2B  depicts anti-decoupling device  230 B, which is a two-piece although otherwise identical version of anti-decoupling device  230 A. As depicted in  FIG. 2B , base  232 B comprises two semi-circular portions that are attached (e.g., via screws, bolts, etc.) to one another at flanges  250 A/ 250 D and  250 B/ 250 C. The two piece construction enables anti-decoupling device  230 B to be coupled to an in-field connector without having to separate the connector. 
     FIG. 3  depicts anti-decoupling device  230 A engaged to two-part electrical connector  100 . Alternatively,  FIG. 3  depicts a new two-part electrical connector that includes anti-decoupling device  230 A. 
   In either case, clips  234  are spread to engage hex mount  130 , thereby securely coupling anti-decoupling device  230 A to connector  100 . Blades  244 A and  244 B of each prong  238  extends into the channels of knurled edge  114  of spin coupling  112 . 
   Prongs  238  are appropriately distanced from spin coupling  112  so that contact between the channels of the spin coupling and edges  246 A and  246 B of blades  244 A and  244 B forces the free-end of the prongs outward (i.e., away from the spin coupling). Since prongs  238  are rigidly attached at their other end to base  232 A, this outward force effectively spring loads the cantilevered prongs  238 . As a consequence, when in contact with the channels, blades  244 A and  244 B are biased toward the spin coupling. 
   This effect is illustrated in  FIG. 4 , which depicts, in phantom, the quiescent or unstressed state of prong  238  (wherein the prong aligns with axis B-B) and a biased state of prong  238  (wherein the prong aligns with axis D-D). As depicted in  FIG. 4 , in the biased state, the free end of prong  238  is forced “outward.” Since the prong is attached to base  232 A at its other end, this outward forcing of the free end results in a “spring bias” that is directed toward spring coupling  112 . Note that in  FIG. 4 , prong  238  exhibits a slight inward deviation in its unstressed or quiescent state (as aligned with axis B-B), as described above. 
   As depicted in  FIG. 5 , due to the v-shape of the prongs, blades  244 A and  244 B on each prong extend in different directions. That is, relative to line E that bisects the “v,” blade  244 B extends toward the “left” and blade  244 A extends toward the “right.” Blade  244 B, which extends to the left, will tend to prevent inadvertent rotation of spin coupling  112  in counter-clockwise direction CC. Blade  244 A, which extends to the right, will tend to prevent inadvertent rotation of spin coupling  112  in clockwise direction C. (Of course, movement in only one of the directions—counterclockwise or clockwise—would loosen the coupling.) Yet, the spin coupling can be manually forced, such that it does not have to be removed to decouple the connector. 
     FIG. 6A  depicts conventional mil type circular connector  650 . In the illustration shown in  FIG. 6A , the connector is attached, via flange  652 , to bulkhead  654 .  FIG. 6B  depicts anti-decoupling device  230 A coupled to flange  652  via clips  234 .  FIG. 6C  depicts an embodiment of an anti-decoupling device wherein the physical adaptation of the base that enables it to couple to the connector are small holes  656  that accept the screws/bolts that attach flange  652  to bulkhead  654 . 
   It is to be understood that the disclosure teaches just one example of the illustrative embodiment and that many variations of the invention can easily be devised by those skilled in the art after reading this disclosure and that the scope of the present invention is to be determined by the following claims. 
   For example, it is to be understood that prongs  238  need not be “folded” as depicted in the illustrative embodiment. Rather, in some embodiments, two blades are attached (e.g., soldered, glued, etc.) to longitudinal members to form a “prong.” 
   In fact, the presence of a structure on anti-decoupling device  230 A that is appropriately described as a “prong” is not necessary per se. What is important is to provide the functionality that is provided by the prongs of the illustrative embodiment. 
   Namely, to provide a means that engages the knurled edge of the spin coupling in such a way as to prevent the spin coupling from moving.