Study on pruning Operation with Electric Circular Saw : Experiment of Cutting Ability and Finishing State

Abstract

We experimented the cutting ability and the finishing state of cutting surface profile according to three type teeth of electric circular saw used at present for artificial green pruning operation. The experimental factors are Saw Type (tipped saw, original saw, filed saw), Size of Twig (8mm, 12mm, 18mm), Cutting Speed (fast, slow), Species of Twig (Sugi, Hinoki), Cutting Angle (90°, 45°), and Moisture Condition of twig (dry, wet, live). We investigated these factors according to the experimental designs of orthogonal array L_<27>(3_<13>). The results are as follows ; we can make cutting time shorter on cutting a twig "fast" and perpendicullarly to longitudinal direction of a twig, and save cutting energy with a thin edge blade and at "fast" Cutting Speed. But on the other hand, we need to prune at "slow" Cutting Speed and perpendicularly to longitudinal direction of a twig for preventing from the defects such as hang-nails or splits on the surface of the pruned tree. As pruning operation is popularly performed in drywinter season, so it is important to pay extra attention to pruning "small" twigs , which are apt to split

電動丸鋸による枝打ち作業について鋸断性能と鋸断表面の仕上がり状態を調べるために, 歯形 (チップドソー, 鋸歯, 目立て歯), 枝の径 (8mm, 12mm, 18mm), 鋸断速度 (速, 遅), 枝の樹種 (スギ, ヒノキ), 鋸断角度 (90°, 45°) および枝の乾燥状態 (乾, 湿, 生) の6因子を取り上げ, 直交表L_<27>(3_<13>)に従って実験計画を組み各因子の要因分析を行った。その結果, 枝軸に直角に素早く枝打ちすることで, 鋸断時間は短縮され, 一方鋸断速度を"速", 刃先の厚みの薄い歯を使用することで鋸断消費エネルギーは少なくなるが, しかし鋸断表面の仕上がり状態を良くするには鋸断速度を遅く, 枝軸に直角に当てる枝打ちがよい。また枝打ちは冬期の乾燥時期が最盛期であるから, 枝打ち面の割れ等を防ぐために, 小さい枝を打つときは特に注意が肝要である。