| 摘要 |
<p>A mobile sprinkler propelled by water pressure has a bellows coupled with a ratchet drive, water being alternately admitted to the bellows under pressure via one conduit and discharged therefrom via another conduit forming part of a squeeze-duct assembly. The assembly includes a rigid housing against whose sidewalls the two conduits are alternately flattened by a rotating valve body coupled with the ratchet drive, each conduit being of substantially O-shaped cross-section in its uncompressed state and consisting of a relatively thick-walled inner tube of elastomeric material, a relatively thin-walled intermediate tube of flexible synthetic-resin fabric and a relatively thin-walled outer tube also made of elastomeric material.</p> |
