| 摘要 |
<p>For breaking and cutting a material having greater compressive than tensile strength, such as concrete, high pressure water from a hose (14) passes through a shaft (12) to a nozzle (16) where it entrains abrasive granules from a hose (66) also connected to the nozzle (16). The upper end of the shaft (12) has a shoulder support for pressure downwards, and the lower end has a support frame (24) with a support wheel (34) which runs over the surface of the material to be broken and cut. A spring (42) biases the shaft (12) and nozzle (16) combination upwardly from the support frame (24) to which a shroud (22) surrounding the nozzle is attached. A pilot hole (84) is cut first, then the tip (82) of the nozzle (16) is pressed sealingly against the mouth (84) of the hole (82) so that fluid pressure built up in the hole (82) fractures the surrounding material.</p> |
