| 摘要 |
<p>There is provided a tool for stone-blowing comprising upper and lower mating parts (13, 14), the upper part being tubular and the lower part being mainly of channel section and having its lower end closed off by a transverse wall. The wall is shaped internally (19) to direct stones laterally and is shaped externally (22) to facilitate driving the tool into the ground adjacent a sleeper (33) so that the open front of the channel communicates with a void (34) beneath the sleeper. On the upper part is a hopper (11) for stones and below the hopper opening into the upper part is a compressed air inlet (26) and a port (24). In use, compressed air is directed at the rear wall and entrains air through the port (24) and the hopper (11) thereby propelling the stones down the tool and through the open front of the channel and into the void (34).</p> |
