Patent ID: 8500176

Claim:
An interlocking engagement mechanism for rotationally engaging a first tubular member with a second tubular member, said first and second tubular members each having a first end and a planar annular end face, wherein said interlocking engagement mechanism comprises: a first engagement means comprising: a plurality of sockets formed in a first region of the annular end face of the first tubular member; and a plurality of locking pins projecting from a second region of the annular end face of the first tubular member, said locking pins being arrayed in a circularly curved pattern at a radius “R” and equally spaced at an arcuate spacing “S”; a second engagement means comprising: a plurality of sockets formed in the annular end face of the second tubular member, said sockets being configured such that any locking pin of the first engagement means is receivable within any socket of the second engagement means, and an indexing pin projecting from the annular end face of the second tubular member, said indexing pin being configured to be receivable within any socket of the first engagement means; and a means for allowing relative longitudinal movement and relative angular displacement between the first and second tubular members to enable engagement and disengagement of the first and second engagement means such that whenever the indexing pin is disposed within a selected socket of the first engagement means, each locking pin will be disposed within a socket of the second engagement means.