Unders1and reactive forces, Procedure, B. tree felling techniques – Poulan 3300 User Manual
Page 12: Footing, B. tree felting techniques, Types of cutting, A. basic cutting technique
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TYPES OF CUTTING
A. BASIC CUTTING TECHNIQUE
1. IMPORTANT POINTS.
a.
b.
c.
Cut wood only.
Do not cut metal, plastics,
masonry, non-wood building materials, etc. Do not
use your saw to pry or shove away limbs, roots or
other objects.
Stop the saw if the chain strikes a foreign
object.
Inspect the. unit and repair or replace
parts as necessary.
Keep the chain out of dirt and sand.
Even a
small amount of dirt willquickiydulla chain and
thus, increase the possibility of kickback.
A
KICKBACK WARNING
Kickbackcan occur when the moving chain Contactsan
object at the upper portion of the tip of the g uide bar or
whenthe wood closes in and pinches the saw chain In
the cut.
Contact at the upper portion of the tip of the
guide bar can cause the chain to dig into the object and
stop the chain for an instant. The result is a
lightning
fast, reverse reaction which kicks the guide bar up and
back toward the operator. If the saw chain Is pinched
along the top of the guide bar, the guide bar can be
drivenrapidlybacktowardtheoperator.EithetoHhese
reactions can cause loss of saw control
which can
resuit in serious injury.
2. UNDERS1AND REACTIVE FORCES
Pinch-Kickback and Pull-In occur when the chain
is suddenly stopped by being pinched, caught, or
by contacting a foreign object in the wood.
This
results in a reversal of the chai n force used to cut wood
and causes the saw to move in the opposite direction of
chain rotation. Either reaction can result in loss of con
trol and possible serious injury.
• Pinch-Kickback
—occurs when the chain, on top of the bar is suddenly
stopped when the top of the bar is used for cutting.
— rapidly drives the saw straight back toward the
operator.
• Pull-In —
—
can occur when the chain on the bottom of the
bar is suddenly stopped.
— pulls the saw rapidly forward.
3. PROCEDURE
a. Accelerate the engine to full throttle just before
entering the cut
by squeezing the throttle trigger.
b. Begin cutting with the saw frame or spur against
the wood.
Figure 15.
c. Keep the engine at full throttle the entire time you
are cutting.
d. Allow the chain to cut for you; exert only light
downward pressure.
If you force the cut, damage to
the bar, chain, or engine can result.
e. Release the throttle trigger as soon as the cut is
completed,
allowing the engine to idle. If you run the
saw at full throttle without a cutting load, unnecessary
wearcanoccurtothechain, bar, and engine.
f. Do not put pressure on the saw at the end of thecut
to avoid losing control when the cut is complete.
g. Stop the engine before setting the saw down after
cutting.
Practice cutting afew small logs using the following techni
que to get the “feel” of using your saw before you begin a
major sawing operation.
12
B. TREE FELLING TECHNIQUES
1.PLAN YOUR SAWING OPERATION CARE- d
FULLY IN ADVANCE
a. Clear the work area. You need a clear area all
e.
around the tree where you can have secure
, footing.
b. Study the natural conditions that can cause
the tree to fall in a particular direction;
f.
1. ) The WIND direction and speed.
2. ) The LEAN of the tree.
3
. ) WEIGHTED with BRANCHES on one side.
g
4.
) Surrounding TREES and OBSTACLES.
c. Look for decay and rot. If the trunk is rotted, h.
it could snap and fall toward the operator.
Check
for
broken
or
dead
branches
which
could fall on you while cutting.
Makesure
thereis
enough
room
forthe
treeto
foil.
Maintain a distance of 2V2 tree lenghs from
the nearest person or other objects. Engine noise
can drown out a warning call.
Remove
dirt,
stones,
loose
bark,
nails,
staples,
and
wire
from
the
tree
where
cuts
are to be made.
Plan to stand on the up-hill side when cut
ting on aslope.
Plan
a
clear
retreat
path
to
the
rear
and
diagonal to the line of fall.
Figure 17.