| 摘要 |
A guard member is mounted on the chain saw for swinging movement between an actuate position and a reset position. The guard member occupies a normal position between the actuate and reset positions. A brake band is integral with a bowed column spring which applies the braking force to arrest movement of the cutting chain. A latching mechanism includes an arm with a latch pin engaged by a yieldable latch finger; this latch finger is integral with the bowed column spring. The guard member deflects the latch finger in response to movement of the guard to its actuate position; this action allows the column spring to apply the brake. The guard member is moved to its actuate position in response to a sudden movement of the chain saw, as in the case of "kickback"; this movement of the guard member is brought about by inertia or the engagement of the guard with the operator's body (most likely the wrist or the back of his hand) during this abrupt movement of the chain saw. Manual swinging of the guard to its reset position deactivates the brake and re-establishes the latch. |
