| 摘要 |
PCT No. PCT/NZ93/00044 Sec. 371 Date Nov. 29, 1994 Sec. 102(e) Date Nov. 29, 1994 PCT Filed May 25, 1993 PCT Pub. No. WO93/23986 PCT Pub. Date Dec. 9, 1993A blade assembly for a lawn mower has a generally planar body (1) rotationally balanced about a vertical central shaft (24), with four projecting blades (6) extending radially from the periphery of the planar body. The planar body (1) is shaped with vanes (3) to form a fan-like impeller. The impeller is arranged to create a strong rotational flow, which carries air and cut material around the blade assembly in use. The projecting blades (6) create an updraft in a peripheral region of the blade assembly, while the vanes (3) of the planar body (1) are shaped to create a regulated, relatively light downdraft towards the central shaft (24). If the mower is provided with an outlet (25) for a catcher, the strong rotational flow overwhelms any influence of the relatively light downdraft, and the air with the clippings is carried centrifugally through the outlet (25). If the outlet (25) is closed or the mower has no catching facility, the air and clippings continue to flow around the blade assembly in a turbulent, shallow spiral inwards and downwards, to be discharged as a mulch into the lawn under the mower.
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