Emergency braking device for chain saw

摘要

An emergency braking device for a chain saw having a clutch drum drivingly connected to the engine crank shaft through a centrifugal clutch. The emergency braking device includes a braking band wound around the clutch drum and connected at its one end to a stationary part of the chain saw. The other end of the braking band is connected to an actuator having a lever member. The emergency braking device further includes a hit switch member adapted to be rotated when hit by an inertia action of an inertia member disposed in the vicinity of a front handle so as to surround the lever member. As a kick-back takes place in the chain saw, the inertia member hits the hit switch member which in turn drives the lever member to actuate the actuator thereby to tighten the braking belt to quickly brake the clutch drum.