1. Field of the Invention
The present invention generally relates to anti-decoupling arrangements for connectors of the type in which coupling is achieved by means of a coupling nut, and more particularly to an anti-decoupling arrangement for an electrical connector that uses a ratchet mechanism to limit rotation of the coupling nut in the decoupling direction and a spiral lock clutch to permit free rotation of the coupling nut in the coupling direction. Still more particularly, the invention relates to improvements on the anti-decoupling arrangement disclosed in copending U.S. patent application Ser. No. 09/391,458, filed Sep. 8, 1999, incorporated by reference herein.
2. Description of the Related Art
A typical connector to which the present invention may be applied includes a connector shell containing electrical contacts and an internally threaded coupling nut rotatably mounted on the connector shell. The connector shell is coupled to a corresponding externally threaded mating connector by means of the coupling nut in such a manner that electrical contacts in the mating connector engage the electrical contacts in the connector shell. The coupling nut is held on the connector shell by one or more retaining rings and/or spring washers that are designed to captivate or press a radial flange of the coupling nut against a corresponding flange or shoulder on the connector shell.
Because the frictional anti-locking force generated by engagement between the coupling nut and connector shell in such an arrangement is insufficient to prevent the coupling nut from rotating in a decoupling direction as a result of vibrations or shocks, compromising seals and possibly affecting the integrity of the electrical connections between contacts, it is conventional to include an additional anti-decoupling mechanism in connectors likely to be used in environments where vibrations or shocks are likely to occur, such as in military high-performance aircraft and other vehicles. The simplest and most common method of preventing unintended decoupling as a result of shocks or vibrations has been to include in the connector a metal ratchet spring having protrusions or dimples at the center of the beam, the ratchet spring being permanently attached to the inside diameter of the threaded coupling nut. The connector shell is provided with ratchet teeth on its outer diameter, which are engaged by the ratchet spring.
One problem with this type of coupling is that the discrete detent positions do not necessarily lie in phase with the fully clamped position of the ring, such that even slight vibrations can cause the ring to back off slightly, which can cause sealing problems. In addition, the detent members in this configuration have very little effective surface area, causing rapid wearing away of the teeth on the ratchet wheel each time the connector is mated or unmated.
A solution to the problems of wear and phasing of the ratchet teeth and detents is described in copending U.S. patent application Ser. No. 09/391,458, which is directed to various improvements in a spiral lock clutch anti-decoupling mechanism originally proposed in U.S. Pat. No. 4,536,048. The anti-decoupling mechanism described in the copending patent application includes a spiral lock clutch that permits free running in the coupling direction, a spring ring, and a tooth wheel all surrounding a connector shell and captured between a snap-ring on the connector shell and an inwardly extending flange on the coupling nut. The tooth wheel includes extensions or knurls that cooperate with corresponding slots or surfaces of the coupling nut to prevent relative rotation between the coupling nut and the tooth wheel, while the spring ring includes spring tines that engage radial cuts in the tooth wheel to permit ratcheting of the tooth wheel relative to the spring ring. The spring ring, in turn, is locked against rotation relative to the spiral lock clutch. During coupling, turning of the coupling nut causes corresponding turning of the tooth wheel. Since the spiral lock clutch is arranged to unwind and permit free running in the coupling direction, the engagement between the spring tines on the spring ring and the radial cuts is not subject to any ratcheting force and the spring ring and spiral lock clutch turn freely with the coupling nut and tooth wheel. During uncoupling, on the other hand, the spiral lock clutch winds tightly against the connector shell, preventing rotation of the spiral lock clutch and spring ring. In order to permit the coupling nut to rotate, a sufficient force must be applied to the coupling nut to permit ratcheting of the spring ring relative to the tooth wheel, i.e., to permit the spring tines to glide over the teeth formed by the radial cuts in the ratchet wheel.
The above-described anti-decoupling arrangement has the advantages, relative to the anti-decoupling arrangement described in U.S. Pat. No. 4,536,048, of attaining a high uncoupling torque due to the use of multiple tines or beams on the spring ring attached to the spiral lock clutch, control of the coupling torque through appropriate choice of the spiral lock clutch, spring tines, and tooth configuration, and simplified assembly to the connector shell by fitting all of the components over the shell, angularly orienting the components, and holding them in place with a retaining ring. Nevertheless, the above-described anti-decoupling mechanism still could benefit from the following improvements:
(i) a greater degree of adjustment of the de-coupling torque; PA1 (ii) a still higher de-coupling torque than can be achieved with the prior arrangement; PA1 (iii) smoother non-binding operation; and PA1 (iv) a less critical assembly method. PA1 (i) arranging the ratchet assembly cantilever beams so that they operate radially outwardly rather than axially; and PA1 (ii) eliminating the ratchet assembly detent ring (i.e., the toothed wheel) used in the prior anti-decoupling arrangement in favor of serrations formed into the inner diameter of the coupling nut.
These improvements are achieved by modifying the anti-decoupling device described in the copending patent application so that the clutch mechanism and the ratchet mechanism operate completely independently of one another in a non-interfering manner, and in particular by:
These modifications not only reduce the number of components and also provide mechanical advantages that increase the range of possible decoupling torques, but they also eliminate any interference between the coupling nut shoulder and the back side of the spiral wound clutch band so as to provide a smoother coupling feel and a more positive and stronger clutch grip, eliminate press fits or keyed components that complicate assembly, permit a stronger and more easily assembled attachment of the spring ring to the spiral wound clutch, reduce tolerance build-up between components (due to the smaller number of axially stacked components), and make it possible to more easily disassemble the anti-coupling mechanism for repair or torque adjustment.