Design optimization and feasibility analysis of pneumatic DTH Hammer with self-rotation bit

This paper presents a novel pneumatic Down-The-Hole (DTH) hammer with self-rotation bit used for rock drilling, and the mechanical structure and working principle are mainly covered. A unique mechanism with ratchet and pawl incorporated in pneumatic DTH hammer is proposed for percussion-rotation drilling to break rock. The drill bit can rotate while the drill pipe stays still because of the structure design and reduces the friction between the drill pipe and borehole. Firstly, the rationality of mechanical invention is verified via the finite-element software ANSYS and the numerical simulation of impact dynamics. Moreover, the energy transfer regulation is revealed in the impact process under differential final impact velocity, which can help practical experience in mechanical design. Finally, based on the experimental study on the novel hammer, we found that its function can satisfy the requirement, as well as overall performance, was improved.