Echo CHAIN SAW SAFETY MANUAL - Manual (Page 7)

7
FORCES YOU MUST CONTROL
This section explains the forces which must be controlled to avoid injury when
operating either a gas or electric-powered chain saw. Always remember that
your best defenses are to exercise caution and use the chain saw properly,
and to be prepared to react to these forces
PULL, PUSH and KICKBACK are terms for the direction a reaction takes.
PULL - When you are cutting on top of a log with the lower portion of the
chain moving toward you, the chain saw will be pulled into the wood and
away from you.
PUSH - Cutting on the underside of a log pushes the chain saw toward you.
PUSH and PULL forces are controlled by anticipating which reaction will
happen and adjusting your position and stance to compensate.
ROTATIONAL KICKBACK - When the chain is moving downward around
the upper nose of the bar, solid contact there may drive the bar tip upward in
an arc toward you. This is an extremely dangerous reaction called Rotational
Kickback. When used alone in this manual, the term kickback will always
refer to the rotational kickback.
Rotational kickback is predictable, preventable and controllable. If the
operator is not alert to the possibility of a kickback, it may come as a
complete surprise. The possibility of kickback can be greatest if the chain is
not a low- or reduced kickback type, or if the bar is not a reduced-kickback
type. The best defense against rotational kickback is making sure the chain
does not contact anything solid at the upper nose of the bar. This can be
assured by proper installation of the Kick Guard ® device.
LINEAR KICKBACK - A sudden PUSH reaction that occurs when the chain
along the top rails of the bar gets pinched in a cut. This type of reaction
pushes the chain saw straight back toward the operator. The Kick Guard
® device on your bar nose acts as a stop against this type of kickback by
stopping the guide bar.
CUTTING ON BOTTOM OF GUIDE-
BAR PULLS SAW AWAY FROM YOU
CUTTING ON TOP OF GUIDE-BAR
PUSHES SAW TOWARD YOU
WOOD
FORCE
REACTION
ROTATIONAL KICKBACK
PINCH
PINCHING TOP OF GUIDE BAR
CAUSES LINEAR PUSH OR
KICKBACK
Rotational kickback
Chain moving downward at impact
PULL
PUSH