| 摘要 |
The present invention relates to improvements in or relating to chain saws (10). In particular, it relates to chain saw switching mechanisms. We describe a chain saw (10) comprising a run-down brake function and a kick-back brake function, wherein the kick-back brake function is provided by a switchable one-way directional drive assembly (33), characterised in that the switchable one-way directional drive assembly (33) also acts to provide the run-down brake function. A cutting chain (15) is carried on a chain bar (16) and driven by means of a chain sprocket (31) rotated by a prime mover (32) through the switchable one-way directional drive assembly (33). Suitably, the switchable one-way directional drive assembly (33) is a freewheel or clutch mechanism (33); preferably a wrap-spring clutch arrangement (33). |
