| 摘要 |
A chain saw safety braking assembly includes a sensing arm pivotally mounted to the housing and having a protrusion. A portion of the sensing arm is located in front of the gripping handle and is arranged to move from a first position to a second position in response to being struck by an appendage of the operator. A flexible brake band is disposed around the peripheral surface of a brake drum, and includes a first end anchored to the housing and a second end coupled to the sensing arm protrusion, such that when the sensing arm moves from the first position to the second position the flexible brake band is moved from a position free of the brake drum to a frictional braking relationship with the brake drum. A latch is rotatably mounted to the housing and is adapted to releasably engage the protrusion on the sensing arm. A spring anchored to the housing cooperates with the latch such that the latch yieldably holds the sensing arm in either the first or the second position. Thus when the sensing arm is struck, it will move from the first position to the second position stopping the chain movement. Additionally, an acceleration sensing assembly may be incorporated to sense acceleration of the saw, again typically due to kickback, and stop the chain should the acceleration rise above a preset level. |
