ICFR – Chainsaw Safety and Operating Handbook
40
The centre row of the saw chain is made up entirely
of identical
drive links
. Engine power is transmitted
via the chain drive sprocket to the
drive
link
tangs
causing the chain to rotate around the guide bar.
The drive link tangs run in the guide bar groove and
stabilise the chain in the lateral direction. The forward
edge of the drive link tang is a rounded hook that acts
as a groove raker/cleaner and a chain lubricant scoop.
Figure 47: Component parts of chain
The two outer rows of links are made up of alternating
cutters and tie straps. The
cutters
are the actual
working parts of the chain. The design and condition
of their cutting edges have a significant influence on
cutting results.
Tie straps
are fitted opposite the cutters on both sides
of the chain to fill the gaps between the cutters. They
have the same basic bottom contour as the cutters
and the two together form a sliding face on which the
chain glides along the guide bar. All chain links are
held together by
rivets
.
To reduce kickback the normal tie strap in front of
the cutter can be replaced with a safety link that has a
higher profile than the normal tie strap or with a special
three-humped safety link. Specially shaped cutters and
drive links can also reduce kickback.
Figure 48: ( a) Normal tie strap, ( b) Safety link with
higher profile, (c) three-humped safety link
14.
CUTTING ATTACHMENT
The cutting attachment consists of the saw chain, guide
bar and chain drive sprocket.
Production results obtained with a chainsaw depend
on the following factors:
•
The competence of the operator.
•
The endurance and fitness of the operator.
•
Selection of the correct chainsaw, including the
cutting attachment, for the task.
•
Condition and maintenance of the cutting
attachment.
The saw chain is the component which does the
actual cutting and could have the greatest influence
on the results achieved. It is essential for the chainsaw
operator, supervisor and manager to have a sound
understanding of the cutting attachment.
Correct use, maintenance and repair of the cutting
attachment is of critical importance and if not correct,
will have a negative effect on productivity, running
costs, the life of the chainsaw and operator endurance.
This section of the Handbook is a guide to assist with
the correct cutting attachment selection for a specific
application as well as the correct use and maintenance
thereof.
Troubleshooting on the cutting attachment has
not been included in this Handbook. Refer to the
manufacturer’s manuals for details.
14.1
S
Aw
chAin
Saw chain manufacturers offer the correct saw chain
for all cutting applications, chainsaw makes and engine
capacities.
The saw chain must be maintained according to
the manufacturer’s specifications to ensure safe,
productive and accurate cutting. A poorly maintained
saw chain is dangerous to use and will reduce the life
of the saw chain, guide bar as well as the engine.
14.1.1
c
omponent
pArtS
of
SAw
chAin
Saw chains are three-link chains, which are assembled
in the same basic pattern. They normally differ only in
the shape and size of the cutters and the individual links.