A rock drill is a tool used for the direct extraction of stone materials. It drills blast holes into rock strata to facilitate the placement of explosives, thereby enabling the extraction of stone or the completion of other rock excavation projects. Furthermore, rock drills can be adapted for use as breakers to fracture hard layers, such as concrete. Based on their power sources, rock drills are classified into four main categories: pneumatic, internal combustion, electric, and hydraulic.
Rock drills operate based on the principle of impact crushing. During operation, a piston executes high-frequency reciprocating motion, continuously striking the shank of the drill bit. Under the force of these impacts, the wedge-shaped tip of the drill bit crushes the rock and penetrates to a certain depth, creating an indentation. After the piston retracts, the drill bit rotates through a specific angle; when the piston moves forward to strike the shank again, a new indentation is formed. The fan-shaped section of rock situated between these two indentations is sheared away by the horizontal force components generated by the drill bit. As the piston continues to strike the shank, compressed air or pressurized water is continuously fed through the central bore of the drill bit to flush rock cuttings out of the hole, thereby creating a circular borehole of the desired depth.