OPERATION
•ALWAYS use blade only for application for which it was intended
•ALWAYS use the correct front handle for the type of blade being used. Echo recommends using a U- Handle for all blade use.
REACTION FORCES - Push/Pull - Kickback/ Kickout
During normal use, operating a brushcutter with a circular metal blade can produce sudden strong reaction forces that are difficult to control. Strong reaction forces can cause a loss of balance or loss of control of the unit, resulting in serious injury to operator and by- standers.
Understanding what causes these reactive forces may help you to avoid them, and can help you to maintain control of the unit if you experience a sudden reaction during cutting. Reactive forces occur when the force being applied by the cutting teeth of a blade meet resistance, and some of the cutting force is directed back toward the unit. The greater the cutting force or the amount of resistance, the greater the reactive force.
Push and Pull Forces
Push and pull forces are reactive forces that push the unit directly toward the operator, or that pull the unit directly away from the operator. These forces are the result of cutting on the sides of the blade. The direction of the force depends on the side of the blade being used, and the direction of blade rotation at the point of contact. The reactive force is in the opposite direction of blade rotation at the contact point, regardless of where the contact is being made. These types of reactive forces are also called “Blade Thrust.”
As shown in the illustration, a blade turning counterclockwise will cause the unit to pull away from the operator if the point of cutting resistance is on the left side of the blade. If the point of cutting resistance is on the right side of the blade, the unit will push back toward the operator. In both examples, the reactive force is in the opposite direction of blade rotation at the contact point where resistance occurs.
PULL
Contact
Point
Contact
Point
PUSH
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