| 摘要 |
The invention relates to rock drills generally known as down the hole drills. During the use of down the hole drills it is inevitable that chippings and other debris collect in the bottom of the hole and unless such chipping and debris are removed the drilling operation will be impeded. In addition it is a frequent requirement that chippings and debris are brought to the surface for analysis. The object of the present invention is to provide a rock drill facilitating the efficient removal of chippings and debris from the bottom of a hole which objective is met by a construction in which pressure air for the purposes of driving the piston within the rock drill is exhausted through an annular passageway between the end of the wear tube and the drill bit and whereby exhaust air passes entirely around the periphery of the drill bit and to the bottom of the hole from where it enters a centre bore through the drill bit and is exhausted through the centre tube of the drill carrying with it all chippings and debris gathered in the bottom of the hole. |
