PROBLEM TO BE SOLVED: To provide a pruning device prevented from occurrence of branch-bite to reduce thrust required for revolving around a tree trunk when performing pruning work while revolving around the tree trunk so as to smoothly perform pruning and to provide a descending/elevating work device elevating while smoothly performing pruning.SOLUTION: The pruning device is structured as follows: a guide bar 71 includes guide rail members 74 and 75 movably supporting a branch-bite preventive member 90 while making a circular locus along the peripheral surface of the tree trunk, and coil springs 97 and 98 the branch-bite preventive member 90 includes an end part on the pruning direction side narrower than the blade width of a chain saw teeth 72. The cutting motion of the chain saw teeth 72 and an action of the guide bar 71 in a pruning direction can be performed under the condition that the end part on the pruning direction side is put between the cut faces of a branch being cut.COPYRIGHT: (C)2011,JPO&INPIT【課題】樹幹を周回をしながら枝打ち作業を行う場合、枝噛みの発生を抑制して樹幹の周回に要する推力の軽減を行うことができ、円滑に枝打ちを行うことができる枝打ち装置及び、円滑に枝打ちを行いながら、上昇することができる昇降作業装置を提供する【解決手段】枝打ち装置は、ガイドバー71の部位には枝噛み防止部材90を、樹幹の周面に沿って円弧状の軌跡を描いて移動自在に支持するガイドレール部材74,75、及びコイルバネ97,98を備える。枝噛み防止部材90は、チェーン歯72の刃幅よりも幅が狭い枝打ち方向側の端部を備えている。枝打ち方向側の端部が切断中の枝の切り口に挟まれた状態の下でチェーン歯72の切断動作及びガイドバー71の枝打ち方向への動作が可能にされている。【選択図】図9
