Many factors influence the occurence and force of the kickback reaction. The type of bar and saw chain you use is a factor in the force of the kickback reaction.
The speed of contact at which the cutter contacts
the object.
Kickback force increase with the rate of impact.
The contact angle between the nose of the bar and the foreign object (fig. 11).
Kickback is most pronounced in the upper quadrant of the bar nose.
MAKITA chain types are designed to reduce kickback forces.
The depth gauges:
Improper lowering of the depth gauges also increases the risk of a kickback.
Saw chain cutter sharpness:-
WARNING!
A dull improperly sharpened chain may increase the risk of kickback. Always cut with a properly sharpened chain.
Devices for reducing the risk of kickback injury
MAKITA have developed a special chain brake to reduce the risk of kickbacks.
This chain brake increases the safety factor on the job, e.g. when the saw suddenly bucks upwards the chain stops rotating within a fraction of a second. A deflection guard on the disengaging lever of the chain brake and a scoop rear handle ensure that the opera- tor’s hands are fully protected at all times.
Kickback tendency increases as the radius or size of the guide bar nose increases. MAKITA have devel- oped guide bars with small nose radius, to reduce the kickback tendency.
WARNING!
No chain brake prevents kickback.
These brakes are designed only to stop the chain, if activated.
To ensure a proper operation of the chain brake, it must be properly maintained. Furthermore, there must be a sufficientdistance betweenthe operator
and the bar to ensure that the chain brake has sufficienttime to activate and stop the chain before potential contact with the operator.
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To avoid kickback
The best protection from
1.Hold the chain saw firmly with both hands and maintain a secure grip.
2.Be aware of the location of the guide bar nose at all times.
3.Never bring the nose of the guide bar in contact with any object. Do not cut limbs with the nose of the guide bar. Be especially careful with small, tough limbs, small size brush and saplings which may easily catch the chain.
4.Don’t overreach.
5.Don’t cut above shoulder height.
6.Begin cutting and continue at full throttle.
7. Cut only one log at a time. | , |
8.Use extreme caution when
9.Do not attempt plunge cuts (see page 13) if you are notexperiencedwith these cuttingtechniques.
I O . Be alert for shifting of the log or other forces that may cause the cut to close and pinch the chain.
11.Maintain saw chain properly. Cut with a correctly sharpened, properly tensioned chain at all times.
12.Stand to the side of the cutting path of the chain saw.
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