| 摘要 |
A lawn mower having a housing and a cutter unit positioned below the housing. The cutter unit comprises an upper rotating cutting unit and a lower stationary cutting unit that is concentric with the upper cutting unit and which have a plurality of upper and lower blades at their borders. Each blade has a cutting surface with a near end close to the border, and a far end away from the border. The blades of the upper cutting unit extend in front of a line passing through the concentric axis and the near end, in the direction of rotation of the upper cutting unit. The upper blades rotate and slide over stationary lower blades, thereby cutting the lawn in a manner similar to a pair of scissors. The angle between the upper and lower blades is preferably 16-20 degrees. The diameter of the upper cutting unit is greater than or equal to the diameter of the lower cutting unit, and the distance from the axis to the far end of the upper blades is greater than or equal to the distance from the axis to the far end of the lower blades. In addition, the lower blades, transverse to the direction of travel of the mower are more closely spaced and more numerous than in the direction of travel. The lower cutting unit is prevented from rotating by a supporting arm, attached to the bottom of the housing, and having projections which engage openings in the lower cutting unit. The supporting arm and lower cutting unit can be rotated 90 degrees to accommodate a change in the direction of travel of the mower. In another embodiment, a plurality of cutter units, all in the same plane, can be provided, along with a supporting plate for preventing the lower cutting units from rotating.
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