| 摘要 |
A drill housing is pivotally connected to the forward end portion of a boom member that swings upwardly from a frame of a mobile drilling machine. A hydraulic motor is secured to the gear housing and provides rotary power from a drive shaft through a pair of meshing gears to a drill chuck that is arranged to receive a drill bit or a roof bolt. A percussion weight is concentrically positioned within the drill housing and is axially aligned with the drill bit for imparting percussive forces to the drill bit. The percussion control is maintained through a servovalve that is supported on the drill housing and is controlled remotely by an electronic control module. The servovalve controls the flow of pressurized fluid from a source through ports in the drill housing connected to the servovalve by conduits to actuate a piston member for oscillation within the drill housing. Oscillation of the piston imparts a percussive force upon the percussion weight which is transmitted to the drill bit. By reversing the fluid flow between the respective ports of the servovalve the piston is oscillated within the drill housing to provide for variable percussive rates at a variable stroke to permit high speed drilling in solid rock. |
