Читать книгу Chainsaw Manual for Homeowners - Brian J. Ruth - Страница 23

Push-back happens when you are cutting from below, using the chain on the top of the guide bar. This chain is moving away from the saw head. You often need to do this when cutting limbs from a tree (here). The force of the moving chain pushes the saw and the operator away from the wood you are cutting. The problem is that if the force pushes the guide bar completely out of the wood, the chainsaw can kick back into the operator. As the bar leaves the cut, if the upper quadrant of the bar nose contacts the wood, the push-back will turn into a kickback.

PUSH-BACK PROBLEM:

When cutting on the underside of a log (with the top of the bar), the saw wants to quickly push away from the wood.

Push-back occurs when cutting on the top of the bar. If not controlled, the bar nose can contact the wood, leading to kickback.

PUSH-BACK SOLUTION:

■ Always cut at full throttle and ease into the cut so the chain is less likely to catch the wood.

■ Do not cut with the upper end (nose) of the bar.

■ Keep your left hand thumb wrapped tightly around the top handle and behind the front guard/chain brake, in position to activate the brake automatically. See top photo (here).

■ Position your body to the left of the line of cut. See here. Then, if there is a kickback, the bar and chain will pass to the right of you.

Wrapping your left thumb around the top handle ensures a firm grip and greater control, and allows the chain brake to operate in the event of kickback.

Stand firmly with legs slightly separated and to the left of the cut line.