| 摘要 |
A rotary actuator is pivotally mounted on the end of a drill boom and supports a rock drill feed bar for rotation about a longitudinal axis of the actuator. The rotary actuator includes a piston with a piston rod portion having external and internal helical splines engaged with cooperating splines on the actuator housing and a rotating shaft, respectively. The shaft is connected to the feed bar and is operable to rotate the feed bar in response to axial movement of the piston. The axis of rotation of the shaft may be coincident with the longitudinal axis of the drill boom. The drill boom is mounted on a rotary actuator for swinging movement about a vertical axis. |
