THREAD COUPLING FOR A DRILL STRING FOR PERCUSSIVE ROCK DRILLING

摘要

Thread coupling for a drill string for percussive drilling. The thread coupling is provided with a male thread (5) and a female thread (4) cooperating therewith. The male thread is arranged on a first drill string element (3) provided with a first impact surface (6). The female thread is arranged on a second drill string element (2) which is provided with a second impact surface (7). The threads are conical. Furthermore the crests (8) of the male thread (5) have a radius of curvature which is more than 30 % of the pitch of the thread.