| 摘要 |
In its preferred form, the present invention provides a blade assembly for a lawn mower, having a generally planar central body (1) rotationally balanced about a vertical shaft (24), with four projecting blades (6) extending radially from the periphery of the central body. The central body (1) is shaped with vanes (3) to form a fan-like structure or impeller. The structure is arranged to create a strong rotational flow, which carries air and cut material around with the assembly in use. The projecting blades (6) create an updraft in a peripheral region of the assembly, while the vanes (3) of the central structure are shaped to create a regulated, relatively light downdraft towards the centre. If the mower is provided with an outlet (25) for a catcher, the strong rotational flow overwhelms any influence of the relatively light secondary flows, and the air and clippings are carried centrifugally outward through the outlet. If the outlet is disclosed or the mower has no catching facility, the air and clippings continue to flow around with the assembly in a turbulent, shallow spiral inwards and downwards, to be discharged into the lawn under the mower as a mulch. |
