ANTI-DECOUPLING DEVICE

Abstract: An electrical connector includes a shell (1) having a radially extending annular flange (6), a coupling nut (2), and an anti-decoupling arrangement. The anti-decoupling arrangement is made up of a flexible friction producing member (100, 110) which is captured in a compressed state to hold the coupling nut (2) in place solely by virtue of the frictional engagement between the friction producing member (100, 110) and the coupling nut (2).

Description: ANTI-DECOUPLING DEVICE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to the field of electrical connectors, and in particular to an anti-decoupling mechanism for an electrical connector of the type which includes plug and receptacle subassemblies and which creates a frictional lock between the mated plug and receptacle subassemblies of the connector to prevent the plug and receptacle from becoming decoupled as a result of vibration forces. 2. Description of Related Art A typical electrical connector to which the present invention may be applied includes a connector shell containing electrical contacts and an internally threaded coupling nut. The connector shell is coupled to a corresponding externally threaded shell by means of the coupling nut in such a manner that electrical contacts i the corresponding shell are aligned with and mate wit contacts in the first connector shell. The problem addressed by the present invention is tha complementary connector shells of the above-described typ may become decoupled as a result of rotation of th coupling nut relative to the first connector shell unde the influence of vibrations, such as might occur if th connector is used in a moving vehicle or aircraft. Th reason such vibrational loosening occurs is that th coupling nut is conventionally held on the first connecto shell solely by means of one or more snap rings designed t captivate a radial flange of the coupling nut, and th frictional anti-locking force generated by engagemen between the snap rings and the coupling nut is insufficien to prevent vibrational rotation. A number of conventional decoupling arrangements whic address the problem of vibrational loosening in this typ of connector are known, including those briefly describe below. Many of these arrangements provide an acceptabl anti-decoupling effect, but each is relatively high in cos and complexity. The improvement provided by the present invention i to reduce the anti-decoupling arrangement to an absolut minimum number of parts, using a completely frictiona locking mechanism, without sacrificing anti-decouplin effectiveness. All of the known prior arrangements requir either a mechanical detent, or a greater number of part than is required for the present invention. U.S. Patent No. 4,588,246, for example, discloses coupling assembly which establishes a lock between connector plug and receptacle using a flexible metal ban having a lock arm. The assembly includes a threade coupling nut having a radial flange positioned between an annular flange of the plug shell and the metal band, such that when the coupling nut is rotated, the metal band radially contracts under the force of the advancing flange to establish a mechanical lock between the connector plug and receptacle. Similarly, U.S. Patent No. 4,462,653 discloses an anti-decoupling mechanism made up of a waved washer disposed between a coupling ring and a sleeve attached to a threaded plug shell. Again, the anti-decoupling arrangement relies upon a mechanical lock formed between a plurality of detents located on the coupling ring and a plurality of corresponding protuberances located on the plug shell. U.S. Patent No. 4,361,373, on the other hand, discloses an anti-decoupling mechanism which includes a waved washer positioned between a shoulder of a threaded plug connector housing and a flange on a coupling ring mounted on the connector housing by a snap ring, the snap ring captivating the coupling ring flange between itself and the waved washer. When the coupling ring is rotated, the waved washer is axially compressed between the shoulder and the flange to create a frictional lock which prevents the connector housing from becoming decoupled. In this arrangement, washers are positioned on either side of the waved washer to prevent wear on the shoulder and flange during use, thereby greatly increasing the cost and complexity of the arrangement. Other anti-decoupling mechanisms of similar relevance are disclosed in U.S. Patent Nos. 4,603,934, 5,141,448, 4,500,153, and 4,534,607. None of these arrangements discloses an anti-decoupling device made up of an exclusively frictional lock consisting of as few elements as the anti-decoupling device of the invention. SUMMARY OF THE INVENTION It is accordingly an objective of the invention t overcome the disadvantages of known anti-decouplin arrangements by providing a frictional substitute fo conventional mechanical anti-decoupling arrangements usin a minimum number of discrete parts and yet which provide any desired level of anti-decoupling protection. This objective is accomplished, according to a firs preferred embodiment of the invention, by providing a anti-decoupling arrangement which includes a flexibl friction producing member in the form of one or more wave washers captivated between a radial flange of a couplin nut and a snap ring located in an annular groov surrounding an unthreaded portion of the plug shell. Th coupling nut flange is positioned so that it adjoins raised shoulder formed on an annular flange extendin radially from an exterior surface of the plug shell. I operation, when the coupling nut is rotated, the wave washers are compressed between the snap ring and couplin nut flange until a tight frictional lock is formed. In a second preferred embodiment of the invention, th snap ring is completely removed and the flexible frictio producing member has taken its place in the annular groove. In addition, the coupling nut flange is equipped on on side with a counterbore for captivating the flexibl friction producing member and compressing them against one of the vertical walls forming the groove, and the othe side of the flange adjoins the raised shoulder of the plug shell such that, in operation, the flexible frictio producing member is captured between an edge of the groove and the coupling nut flange. In a third preferred embodiment of the invention, th flange of the coupling nut is positioned between a sna ring positioned in a groove in an unthreaded portion of the plug shell and at least one waved washer, and the waved washer adjoins and is compressed against the raised shoulder of the unthreaded plug shell such that, in operation, the flexible friction producing member is compressed between the raised shoulder of the unthreaded portion of the plug shell and the coupling nut flange as the coupling nut is tightened during coupling to a mating connector. Finally, according to a fourth preferred embodiment of the invention, the anti-decoupling arrangement of the first three embodiments of the invention is equipped with an anti-vibration feature, which may be a ring containing a projection which engages a hole or groove formed around the exterior surface of the plug shell shoulder when the subassemblies are mated to their full extent. The anti- vibration feature adds a mechanical lock to the frictional lock already established by the between waved washer and the coupling nut flange. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional side view of an anti- decoupling device for an electrical connector according to a first preferred embodiment of the invention. Figure 2 is a cross-sectional side view of an anti- decoupling device for an electrical connector according to a second preferred embodiment of the invention. Figure 3 is a cross-sectional side view of an anti- decoupling device for an electrical connector according to a first preferred embodiment of the invention. Figure 4 is a cross-sectional side view of an anti decoupling device for an electrical connector according t a second preferred embodiment of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in Figures 1-4, the anti-decouplin arrangements of the four preferred embodiments of th invention share a connector shell 1 on which is to b fitted a coupling nut 2. The coupling nut is of standar type and is designed to be threaded onto a correspondin externally threaded portion of a mating connector (no shown). Connector shell 1 is illustrated as being in th form of a plug shell of the type disclosed in the above mentioned U.S. Patent No. 4,462,653, although it will b appreciated by those skilled in the art that the principle of the invention may be extended to cover a variety o different connector shell configurations, so long as th context is one which involves a connector shell to which coupling nut is to be non-rotatably affixed. In each of the preferred embodiments, plug shell includes a cylindrical forward portion 3 which encloses contact pin-containing insert (not shown), a rearward en 4 having external threads 5, and an external radial flang 6 of the type which in tne prior art accommodated ratche teeth, but which is replaced in the preferred embodiment by a square shoulder 7 located medial the ends of th shell, the square shoulder 7 defining together with thread 5 a medial unthreaded portion 8 of the connector shell 1 The inclusion of a square shoulder provides a more complet seal than the conventional ratchet teeth and therefor increases EMI protection for the signal contacts in th connector. Medial portions 8 in each of the embodiment differs as follows: In the embodiment shown in Figure 1, medial portion 8 includes a groove 9 sufficiently large to accommodate a snap ring or threaded nut and which is set back from the annular flange by a distance S sufficient to accommodate a rear flange portion 10 of the coupling nut, and a flexible, friction producing member, depicted as two stainless steel waved washers 100 and 110. It will be appreciated by those skilled in the art that while two flexible devices are illustrated, a single flexible friction producing member, or more than two such devices, may be substituted. In addition, the flexible friction producing member need not necessarily be made of metal, but rather could be made of rubber or plastic. In operation, when coupling nut 2 of the embodiment depicted in Figure 1 is rotated, the flexible friction producing member 100,110 is compressed between the snap ring or unthreaded nut 11 to thereby increase the frictional force provided by the anti-decoupling arrangement. Those skilled in the art will appreciate that by suitably selecting distance S based on the final tightening torque of the coupling nut when assembled to the mating connector shell, the thickness of the snap ring or unthreaded nut 11, and the frictional properties and compressibility of the tlexible friction producing member 100,110, any desired anti-decoupling force can be obtained. In the embodiment shown in Figure 2, medial portion 8 includes a groove 12 arranged to directly accommodate the compressed flexible friction producing member (100,110). In addition, in this embodiment, a first surface of the rear flange portion 10 of the coupling nut includes a counterbore 13 for captivating the flexible friction producing member and compressing it against one of the vertical walls forming the groove, the second surface of the coupling nut flange adjoining shoulder 7 on flange 6 of the connector shell 1. In operation, the anti-decoupling force is obtained i this embodiment when the flexible friction producing membe 100,110 is compressed between the one of the vertical wall of groove 12 and the rear flange 10 of the coupling nut a the coupling nut is rotated. Again, those skilled in th art will appreciate that by suitably selecting the distanc S' between shoulder 7 and the rearwardly situated vertica wall of groove 12, based on the final tightening torque o the coupling nut when assembled to the mating connecto shell, the thickness of the snap ring or unthreaded nut 11 and the frictional properties and compressibility of th flexible friction producing member 100,110, any desire anti-decoupling force can be obtained. The embodiment shown in Figure 3 is similar to th embodiment shown in Figure 1, except that the compresse flexible friction producing member (100,110) is positione between a front surface 14 of flange 10 of the coupling nu 2 and shoulder 7 of the annular flange 6. A snap ring o threaded nut 15 positioned in a groove 16 is again used t hold the assembly in place. This embodiment allows sligh movement of the coupling nut in the uncoupling directio while still maintaining a metal-to-metal friction lock (i a metal flexible friction producing member, such as a least one waved washer, is used). In operation, in the embodiment illustrated in Figur 3, the flexible friction producing member is compresse between the raised shoulder 7 and the coupling nut flang 10 as the coupling nut is tightened during coupling to mating connector. In this embodiment, however, the anti decoupling force is determined solely by the properties o the flexible friction producing member itself, snap ring 1 serving to loosely hold the coupling nut in place befor coupling. The final embodiment shown in Figure 4 involves the use of the preferred anti-decoupling arrangement of any of the embodiments shown in Figures 1-3 (the arrangement of Figure 1 is shown, but either of the other two embodiments could easily be substituted) with a conventional antivibration feature involving a spring member 17 and detent 18. Having thus described a preferred embodiment of the invention, however, the inventors recognize that numerous variations of the preferred embodiment will undoubtedly occur to those skilled in the art, and intend that the invention be defined to include all such variations. For example. Consequently, it is intended that the invention not be limited to the preferred embodiment described herein and illustrated in the drawings but rather that it be limited solely by the apDended claims.

Claims: WE CLAIM : 1 . An electrical connector, comprising: an electrical connector shell having a radiall extending annular flange which includes a shoulder; a coupling nut having a threaded portion and a flang portion; and an anti-decoupling arrangement, the improvemen wherein: the anti-decoupling arrangement consists of a flexibl friction producing member and means for capturing th flexible friction producing member and holding it in compressed state against said flexible friction producin member when the coupling nut is threaded onto a matin connector shell. 2. An electrical connector as claimed in claim 1, wherei the capturing means comprises a groove in said connecto shell, and an annular member positioned in said groove fo holding said flexible friction producing member between th annular member a first surface of said flange portion o the coupling nut, whereby a second surface of the flang portion of the coupling nut is held against said annula flange. 3. An electrical connector as claimed in claim 1, wherei the capturing means comprises a groove in said connecto shell, and said flexible friction producing member is retained in said groove and thereby caused to engage first surface of said flange portion of the coupling nut, whereby a second surface of the flange portion of th coupling nut is held against said annular flange. 4. An electrical connector as claimed in claim 1, wherei said flexible friction producing member is arranged t engage a first surface of the flange portion of th coupling nut, whereby a second surface of the flang portion of the coupling nut is held against said annular flange, and wherein said first surface of the flange portion of the coupling nut is formed by an undercut in said flange portion. 5. An electrical connector as claimed in claim 1, wherein said capturing means comprises a groove in said shell and an annular member positioned in said groove to engage a first surface of the flange portion of the coupling nut, and wherein said flexible friction producing member is captured between a second surface of the flange portion of the coupling nut and said shoulder of the annular flange. 6. An electrical connector as claimed in claim 1, further comprising anti-vibration means in the form of a spring member positioned between the coupling unit and the shell and including a mechanical detent for positioning in a corresponding opening in a circumferentially extending surface of the connector shell.

Inventors: FELTMAN WALTER L, MACAVOY DAVID WARREN, MIKOLAICYK JOHN HENRY, OLEKSIK GREGORY JOHN, FELTMAN, WALTER, L., MACAVOY, DAVID, WARREN, MIKOLAICYK, JOHN, HENRY, OLEKSIK, GREGORY, JOHN
Applicants: AMPHENOL CORP, AMPHENOL CORPORATION
Application year: 1996
Main classification: H01R13
IPC codes: H01R13