| 摘要 |
A one-pass bucket includes a top wall, a bottom wall, a rear wall and a pair of side walls diverging forwardly from the rear wall to an open front end of the bucket, wherein the curved end walls extend convexly from the bottom wall to the top of the end wall at a forward edge thereof, and extending substantially diagonally upwardly from the bottom at a rearward edge so that the forward edge of the curved end wall curves upwardly towards the plane of the top wall so as to intersect the plane of the top wall non-tangentially and the rearward edge extends diagonally to intersect the plane of the top wall whereby a round bottom ditch is formed by rotating one of the curved end walls down and dragging that curved end wall through the soil longitudinally of the proposed ditch in a single pass.
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