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KICKBACK SAFETY PRECAUTIONS
WARNING:
Kickback may occur when the moving
saw chain (near the upper quadrant of the bar nose)
contacts a solid object or is pinched.
The reaction of the cutting force of the chain causes a rotational
force on the chainsaw in the direction opposite to the chain
movement. This may fling the bar up and back in an uncontrolled
arc mainly in the plane of the bar. Under some cutting
circumstances the bar moves towards the operator, who may
suffer severe or fatal injury.
Kickback (Pic. 2) may occur when the nose of the guide bar is
pinched unexpectedly, unintentionally contacts solid material in
the wood or is incorrectly used to begin a plunge or boring cut.
It may also occur during limbing. The greater the force of the
kickback reaction, the more difficult it becomes for the operator
to control the saw. Many factors influence the occurrence and
force of the kickback reaction. These include chain speed, the
speed at which the bar and chain contact the object, the angle
of contact, the condition of the chain and other factors.
WARNING:
Use extreme caution when cutting small size
brush and saplings which may easily catch the chain
and pull you off balance.
PULL-IN
Pull-in occurs when the chain on the bottom of the bar is
suddenly stopped when it is pinched, caught or encounters a
foreign object in the wood. The reaction of the chain pulls the
saw forward and may cause the operator to lose control.
Pull-in frequently occurs when the bumper spike of the saw is
not held securely against the tree or limb and when the chain is
not rotating at full speed before it contacts the wood.
To Avoid Pull-In (Pic. 3)
1. Always start a cut with the chain rotating at full speed and
the bumper spike in contact with the wood.
2. Pull-in may also be prevented by using wedges to open the
kerf or cut.
PUSHBACK
Pushback occurs when the chain on the top of the bar is
suddenly stopped when it is pinched, caught or encounters a
foreign object in the wood. The reaction of the chain drives the
saw straight back toward the operator and may cause loss of
saw control. Pushback frequently occurs when the top of the
bar is used for cutting.
To Avoid Pushback (Pic. 4)
1. Be alert to forces or situations that may cause material to
pinch the top of the chain.
2. Do not cut more than one log at a time.
3. Do not twist the saw when withdrawing the bar from a
plunge cut or underbuck cut because the chain can pinch.
PIC. 4
PIC. 3
PIC. 2
KICKBACK
ZONE
Содержание PG6133
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