Positive lock coupling

A threaded coupling apparatus for interconnecting ends of first and second fluid-carrying conduit members in a fixed releasable locking relationship, said apparatus comprising:

• first and second coupling members circumferentially engageable with the ends of the conduit members to hold them in fluid communication, said coupling members being rotatable with respect to each other in a locking direction to a locked position and in an opposite unlocking direction to unfasten said coupling apparatus;
• a peripheral facing means located on each of said first and second coupling members, one of said peripheral facing means having first complementary locking elements in the form of a first relief of a first configuration and a second relief of a second and different configuration, said second relief being spaced peripherally from said first relief, and the other of said peripheral facing means having second complementary locking elements in the form of a first protrusion for cooperatively mating with said first configuration and a second protrusion said second configuration and peripherally spaced from said first protrusion so that when said first protrusion is aligned with said first relief, said second protrusion also is aligned with said second relief so that one of said peripheral facing means is movable axially toward the other of said peripheral facing surfaces to snap said first and second protrusions into said first and second reliefs, respectively, to positively lock said first and second coupling members in the fixed rotational position;
• cooperating threads on said first and second coupling members for moving said first and second peripheral facing surfaces toward each other when said coupling members are rotated with respect to each other to said locked position;
• and
• resilient means adjacent one of said first and second complementary locking means for urging said peripheral facing means toward each other so that said first and second complementary locking means on one of said peripheral facing means contacts and subsequently locks into the other of said peripheral facing means when said first and second complementary locking means become aligned to hold them in a fixed rotational and locked position.

A method of releasably locking ends of first and second fluid carrying conduit members in a fixed relationship, said method comprising the steps of:

• providing first and second threaded coupling members with respective peripheral facing surfaces, each having a locking means located thereon;
• engaging each locking element with the peripheral facing surface of the other coupling member;
• rotating the threaded coupling members through a predetermined annular rotation to draw them longitudinally toward each other;
• longitudinally moving the complementary locking elements after a predetermined angular rotation of the first and second coupling members with respect to each other to engage and positively lock the first and second coupling members to prevent further relative angular rotation therebetween;
• providing an indicator stripe around the periphery of one of the coupling members which is visible during coupling;
• and
• covering the indicator stripe when the locking elements become engaged.

A method of releasably interconnecting ends of first and second coupling members, having first and second peripherally facing surfaces, respectively, which are attached to first and second fluid-carrying conduit members, respectively, said method including the steps of:

• providing a first relief having a first configuration and a second relief having a second and different configuration on the first peripheral facing surface, the second relief being spaced peripherally from the first relief;
• providing a first protrusion for cooperatively mating with the first configuration and a second protrusion for cooperatively mating with the second configuration on the second peripheral facing surface, the second protrusion being spaced peripherally from the first protrusion so that when the first protrusion is aligned with the first relief, the second protrusion is aligned with the second relief;
• aligning the first protrusion with the first relief and the second protrusion with the second relief;
• and
• moving the first and second peripheral facing surfaces toward each other to bring the first protrusion into locked engagement within the first relief and the second protrusion into locked engagement with the second relief to releasably interconnect the ends of the first and second coupling members.

A method of releasably interconnecting ends of first and second coupling members, having first and second confronting pipe ends, respectively, which are attached to first and second fluid-carrying conduit members, respectively, said method including the steps of:

• providing an externally threaded coupler on one of the pipe ends;
• positioning a lock ring, which has first peripherally spaced locking elements, on the coupler adjacent the threads for longitudinal movement therealong;
• providing a rotatable nut, having internal threads and second peripherally spaced locking elements, on the other of the pipe ends;
• threading the nut on the coupler so that the nut engages and displaces the lock ring longitudinally away from the coupler threads and to interconnect the ends the first and second coupling members;
• aligning the first and second peripherally spaced locking elements during threading of the nut on the coupling;
• and
• moving the lock ring in the opposite direction to engage the first and second peripherally spaced locking elements.