PROBLEM TO BE SOLVED: To provide a rotary blade unit attached to the tip part of an operation rod of a bush-cutter in which swinging blades are prevented from being separated out of a rotary substrate.SOLUTION: A rotary blade unit 20 includes a rotary substrate 21 rotatably attached to the tip part of an operation rod 11 of a bush-cutter 10, swinging blades 22 swingably supported to the rotary substrate 21, and swinging support shafts 23 for swingably supporting the swinging blades 22 to the rotary substrate 21. The rotary blade unit also includes separation preventing means 30 for preventing the swinging blades 22 from being separated out of the rotary substrate 21. The separation preventing means 30 has separation preventing shafts 31 fixed to the swinging blades 22 and penetrating through the rotary substrate 21, and separation preventing grooves 32 formed in the rotary substrate 21 inserted so that the separation preventing shaft 31 moves according to the swing of the swinging blades 22. Even if the swinging support shafts 23 are broken, the separation preventing shafts 31 are engaged with the separation preventing grooves 32 and the swinging blades 22 are prevented from being separated out of the rotary substrate 21.COPYRIGHT: (C)2015,JPO&INPIT【課題】刈払機の操作棹の先端部に取り付けられる回転刃ユニットにおいて、回転基板から揺動刃が離脱するのを防ぐ。【解決手段】回転刃ユニット20は、刈払機10の操作棹11の先端部に回転自在に取り付けられる回転基板21と、回転基板21に揺動自在に支持された揺動刃22と、揺動刃22を回転基板21に対して揺動自在に支持する揺動支持軸23とを備え、揺動刃22が回転基板21から離脱するのを防ぐ離脱防止手段30を備えた。離脱防止手段30は、揺動刃22に固定されて回転基板21を貫通する離脱防止軸31と、離脱防止軸31が揺動刃22の揺動に応じて移動するように挿通される回転基板21に形成した離脱防止溝32とを有し、揺動支持軸23が折損しても、離脱防止軸31が離脱防止溝32に係合して、揺動刃22が回転基板21から離脱しないようにした。【選択図】図3
