Couplings for tools and safety devices used in oil-wells

Claim 1

A coupling for connecting together two tools having recessed ends, said coupling comprising a hollow substantially cylindrical shell having two radially opposed slots therein, with both slots positioned at substantially equal but opposite angles to the longitudinal axis of the shell, two parallel members having partcylindrical outer surfaces extending through said shell to project from both ends thereof, said parallel members being provided with abutments which cooperate with abutments on said shell to prevent longitudinal movement of said parallel members in said shell, and having transversely enlarged end portions and transversely narrower intermediate portions therebetween, and at least one wedge member slidably positioned between said parallel members and carrying pin means projecting into said slots, said parallel members having inwardly sloping shoulders near each end portion whereby rotation of said shell relative to said wedge member advances said wedge member between the shoulders near one end of said coupling to further separate the parallel members at said one end, while permitting said parallel members to approach each other more closely at the other end of said coupling.