PROBLEM TO BE SOLVED: To achieve a lawn mower preventing reliably biting of a fixed blade and rotation blade, allowing the rotation blade and fixed blade to press each other with relatively large force, and thereby obtaining favorable cutting force.SOLUTION: A lawn mower includes a rotation blade 2 attached in a horizontal direction in a body frame 1 and a fixed blade 6 arranged parallelly to the rotation blade and mowing is performed between the fixed blade 6 and rotation blade 2. A plurality of spiral blades 3 are arranged at equal intervals concentrically with a rotation shaft 4. An arcuate extension part 5 is formed at both edges of the spiral blade, the extension part having a fixed dimension from a center of the rotation shaft 4 and equal to a dimension to a cutting blade of the spiral blade. The extension part 5 is joined to a next spiral blade and a cutting blade 3a of the spiral blade is flush with an outer peripheral face 5a of the extension part 5. The extension part 5 is favorably inclined from both edge positions toward an inner part of a next spiral blade.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2018,JPO&INPIT【課題】 固定刃と回転刃の噛み込みをより確実に防止し、回転刃と固定刃を比較的大きな力で押圧させることによって良好な切断力を得ることができる芝刈り機を実現する。【解決手段】 本体フレーム1の水平方向に取り付けられる回転刃2と、回転刃と平行に固定刃6を配置し、固定刃6と回転刃2の間で刈り取りを行う芝刈り機において、複数の螺旋刃3を回転軸4の同心軸上の等間隔に配置し、螺旋刃の両端に回転軸4の中心から一定寸法であって螺旋刃の切り刃までの寸法に等しい弧状の延長部5を形成する。延長部5は次位の螺旋刃に接合して螺旋刃の切り刃3aと延長部5の外周面5aを面一に形成する。延長部5は、両端位置から次位の螺旋刃の内方に向けて傾斜させるのが好ましい。【選択図】 図1
