Makita DCS 6400, DCS6401, DCS 7901 manual Kickback, Reactiveforces duringthe cut, includingkickback

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In order to keep control of your saw, always maintain a firm foothold. Never work on a ladder, in a tree or on any other insecure support. Never use the saw above shoulder height (fig. 9).

Positionthe chain saw in such a way that your body is clear of the cuttingattachmentwheneverthe engine is running (fig. 10).

Don’t put pressure on the saw when reachingthe end of a cut. The pressure may cause the bar and rotating chain to pop out of the cut or kerf, go out of control and strike the operator or some other object. If the rotating chain strikes some other object a reactive force (see pages 10 to 12 ) may cause the chain to strike the operator.

Reactiveforces duringthe cut, includingkickback

WARNING!

Reactiveforces, that may occur during any cut are kickback, pushback and pull-in. Reactive forces can be dangerous! In any chain saw, the powerful force usedto cut wood can be reversed (and work against the operator).

Ifthe rotatingchain is suddenlystopped by contact with any solid object like a log or branch or is pinched,the reactiveforces instantlyoccur. These reactiveforces may result in loss of control which may, in turn, cause serious or fatal injury. An understanding of the causes of these reactive forces may help you avoid loss of control.

The most common reactive forces are

-kickback,

-pushback,

-pull-in.

Kickback:

Kickback occurs when the upper quadrant of the bal nose contacts a solid object in the wood or is pinched (fig. 11). The reaction of the cutting force of the chain causes a rotational force of the chain saw in the direc tion opposite to the chain movement, mainly in the plane of the bar. This may flincJ the bar in an uncon- trolled arc towards the operator.

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This reaction can occur in a fraction of a second and under some circumstances, cause the guide bar and

chain to strike the operatorwith enough force to cause severe or fatal injury. It may also occur during limbing. It also occurswhen the noseofthe guide bar is pinched unexpectedly, unintentionally contacts solid material in the wood (fig.12) or is incorrectly used to begin a plunge or boring cut.

The greater the force of the kickback reaction, the more difficult it becomesfor the operator to controlthe saw.

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