Kickback effect
The non-return effect or rebound effect (English kick back effect ) is a rear and turning up of a chain saw when it is cut with the tip of the guide bar.
Kickback area
The kickback area is the front upper angular section of about 90 ° of the tip of the saw bar.
danger
If you saw with the tip or the front of the saw bar and the kickback area touches a solid object, the chainsaw can be thrown back quickly and with great force. The chainsaw operator usually cannot hold the saw and is injured because the saw blade is hit upwards towards the face and upper body.
The kickback effect can occur when delimbing or incorrectly cutting trees under tension, or when accidentally touching an obstacle.
The smaller the radius of the front sprocket of the saw bar, the lower the risk of kickback, as the kickback area becomes smaller.
consequences
The consequences of the kickback effect can be severe facial and shoulder injuries. The sharp teeth of the saw chain , which work according to the planing principle, can cause serious injuries even if the chain brake is triggered .
Avoidance
As a matter of principle, it should not be sawn with the front upper quadrant of the saw bar. If half chisel chains are used instead of full chisel chains and the chain is well sharp, the risk of kickback can be significantly reduced. There are also special low-kick-back chains which, due to their structure, have a lower risk of kickback. However, this is at the expense of the sawing performance.
Nevertheless, it is sometimes necessary to cut with the tip of the saw bar, for example when a plunge cut is necessary for trees that are under tension . This can also be necessary when felling trees that hang forward ( clip-ons ). Therefore, special working techniques are necessary here, which should be learned and practiced in a chainsaw course for additional safety.