Hazard Alert No 112 Blade failure of a wood chipper - SafeWork SA ...

HAZARD ALERT
No. 112 ISSUED: OCTOBER 2012
BLADE FAILURE OF A WOOD CHIPPER
SUMMARY OF INCIDENT
A wood chipper machine was in use when a sudden
failure resulted in a cutting blade shattering and
large fragments were ejected through the solid metal
guard.
The failure had the potential to cause serious injury
to the wood chipper operator or other workers in the
vicinity.
The chipper cutting disc, remaining blade and
surrounding guarding sustained extensive mechanical
damage, with debris piercing through the heavy duty
metal guard.
BACKGROUND
Damaged metal guard
Wood chippers are powerful machines that are used
to reduce tree trunks and branches into small wood
chips through the action of a cutting disc.
Operating wood chippers can be dangerous for
operators and others in the vicinity of the machine.
When workers feed tree limbs and branches into
the chipper, they are at risk of getting caught in the
material and being pulled into the cutting area.
In addition to the hazard of being drawn into the
cutting zone, materials ejected from the wood chipper
could also cause serious injuries and even death.
These materials may include wood, metal fragments
or stones.
POTENTIAL CAUSES
• Failed main bearing supporting the cutting disc.
• Low grade bolt used in securing the blade to the
disc.
• Loose / incorrectly adjusted blade.
• Blunt blade / poor blade sharpening technique.
• Brittle blade material or wrong material selection.
• Damaged or over-torqued blade retaining bolts.
• Material fatigue that may have initiated cracks in
the blade.
• Different length blades.
• Foreign material trapped between blade and
cutting disc during assembly.
• Too high a timber feed rate into the machine.
• Mulching of high hardness timber.
• Metal / foreign object drawn into the chipper.
Cutting blade and retaining bolts
ACTION REQUIRED
• Use the wood chipper in accordance with
manufacturer’s instructions.
• Ensure the wood chipper has the appropriate safety
devices installed (e.g. feed control bar) and they are
regularly tested.

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The manufacturer of the “Super Axe” has developed a that any axe blade control systems are properly labelled and
modification • Check the that condition includes of a double blades action prior to to startup, interlock the cannot be inadvertently activated.
blade including control, minimising the securing unintended bolts. operation.
• Ensure workers wear the appropriate Personal All operators should be trained in the operation of log
Install Protective the modification Equipment provided (PPE). by the manufacturer. splitting machines.
• All repairs/servicing must be done by competent Safety Procedures should include a system of work
Owners persons. and operators of machines with a similar operating to shutdown or isolate the axe control system before
mechanism
• Establish
should
a regular
check
servicing,
their machines
maintenance
to see if
and
similar attempting to free a log stuck on the axe blade.
modifications
inspection
are
program.
required.
Repair or replace faulty parts
as identified from inspection.
Safety procedures should be regularly monitored and
Owners and operators of log splitters should make sure reinforced
• Ensure that a hazardous work zone is appropriately
that any axe blade control systems are properly labelled and
identified to exclude members of the public and
cannot be inadvertently activated.
FURTHER INFORMATION
non-essential workers.
For further information please contact:
All operators should be trained in the operation of log
splitting machines.
SafeWork SA
GPO Box 465
ADELAIDE SA 5001
Safety Procedures should include a system of work
to shutdown or isolate the axe control system before
attempting to free a log stuck on the axe blade.
Safety procedures should be regularly monitored and
reinforced
This incident may be unique to the leg operated axe control
of the Whitlands Engineering “Super Axe”
A stirrup fits around the operator’s upper right leg, with
movement of the leg causing the axe blade to either raise
or lower.
When a log stuck on the axe blade, the operator used
both hands try and lever the log off the axe blade, as
the operator moved, the machine accidentally operated,
crushing three fingers of the worker’s left hand between
the log and the machine table.
ACTION REQUIRED
The manufacturer of the “Super Axe” has developed a
modification that includes a double action to interlock the
blade control, minimising unintended operation.
Install the modification provided by the manufacturer.
Owners and operators of machines with a similar operating
mechanism should check their machines to see if similar
modifications are required.
Issued: October 2012
Owners Review: and operators October 2014
of log splitters should make sure
CONTACT DETAILS
Country Offices
Berri, Mount Gambier, Port Lincoln, Port Pirie and Whyalla
Help Centre
Library and Bookshop
100 Waymouth Street, Adelaide
Telephone: 1300 365 255
Website: www.safework.sa.gov.au
Issued: July 2011
Review: July 2013
SafeWork SA: GPO Box 465, ADELAIDE SA 5001
Country offices: Berri, Mount Gambier, Port Lincoln, Port Pirie and Whyalla
Library and Bookshop: Ground floor, State Administration Centre
200 Victoria Square, Adelaide
Help Centre: 1300 365 255
www.safework.sa.gov.au
This information is provided to offer
guidance on a particular aspect of
legislation. It is not to be taken as a
statement of law and must not be
construed to waive or modify any
legal obligation.