Hand connect-disconnect coupling for blast furnace tap hole drill rod assembly

摘要

The component parts of a drill rod assembly on a blast furnace tap hole drill are joined together by providing a unique threaded coupling in which the threads do not torque tightly against each other but maintain a loose, floating relationship to thereby permit the coupling to be threaded together by hand without the use of a wrench, and such that the drilling action of the percussion drill will maintain the components in a joined relationship.