Percussive Augmenter of Rotary Drills for Operation as a Rotary-Hammer Drill

A piezoelectrically actuated percussive bit augments rotary drills to form a rotary-hammering drill/sampler. The Percussive Augmenter of Rotary Drills (PARoD) bit has two key modalities: one with vibrating free-mass and one without. In the first modality, the bit is designed to rotate the tip and transmit the impact of a free mass, while the complete bit turns as a single unit. In the second modality, the ultrasonic hammering action from the piezoelectric stack and the rotation from a commercial drill are applied directly to the drilled object. The PARoD tool includes slots to ensure that the tip of the bit does not rotate separately from the piezoelectric actuator. The bit employs electric and mechanical slip rings to transfer electric power, as well as water (for removal of cuttings and bit cooling), while freely turning the bit. The cooling plumbing can be connected to the related fixtures on heavy-duty commercial rotary drills.