高速度カメラによる単一チェンソー歯の木材切削状況の観察

Abstract

特異な形をしているチッパー型チェンソー歯の木材切削状況を高速度カメラ (7000コマ/秒)を用いて撮影し, それについて検討した。結果は表1に示されている。チップの切削型が切削エネルギーの大小を左右するのは明らかであるが, 同時に生成したチップの挙動が, チェンソー歯の歯室の形状及び大小, ひいては歯型そのものに大きく影響を与えることも確かであろうと考える。

A chipper type chain-saw tooth has the peculiar shape like a japanese letter "つ", and has both the side plate edge (the planing edge) and the top plate edge (the shearing edge). It is, therefore, supposed that the characteristic cutting is being performed. So, a chain-saw tooth was fixed at the end of the pendulum of a pendulum dynamometer, and with a high speed camera (about 7000 sceans/sec.), the situation which the tooth cuts a specimen made from japanese cypress was photographed for various cutting direction, depth of cut, and moisture condition. The results are shown in Tab. 1. In the cutting direction of "Cross.", the shearing type of chip was always produced and the chips scattered rearward of the tooth. In the cutting direction of f〟, both the flow type and the broken type of chip were produced according to moisture condition. In the cutting direction of f⊥, two types above mentioned were produced according to depth of cut. While it is evident that the types of chip formed influences on cutting energy, behavior of the chip (continious or not, or, to scatter or to curl) has, the authors think, large role on the shape and the capacity of a gullet of a chain-saw tooth, and has finally influence on the shape of the tooth itself.