| 摘要 |
Percussion apparatus having a compressed air inlet (3) and serving to impart percussive movement to a tool (10), the said tool (10) sliding inside an envelope (1) fixed to the apparatus and being terminated by a spherical portion (22), includes the improvement wherein the said tool (10) includes a hollow tube (13) with one end (21) holding a ball (22) captive, which ball is urged against the end (21) by a spring (24) lodged in the tube (13). When the ball (22) is worn, it is easily changed. |
