| 摘要 |
A rock drill system uses a high frequency, low energy per blow percussive drill device to drive a rock drill bit having a cylindrical sleeve and a breaking bar within the sleeve adjacent the cutting edge of the bit. The bit is operated without rotation and the low energy, high frequency enables operation without destroying the bit. A peening effect occurs around the outer circumference of the drilling end of the bit to create a slightly larger diameter than the diameter of the bit thereby enabling easy withdrawal from the hole. <IMAGE> |
