Detecting loose screw joints in rock drills during drilling, by comparing drill strand vibration patterns with known ones obtained when screw joint is loose

摘要

Vibrations from the drill strand (1) are detected whilst the drill strand is struck against the ground (3), an analysis device (4) compares the vibrations with known vibration patterns and a signal is sent to the rock drill control system (5) so that drilling can be stopped if a pattern is detected which corresponds to one indicating a loose screw joint.