Incident

A farm employee suffered severe crushing injuries to his hand when the 15kg Post Cap of the post rammer fell onto his hand. Users of older models of a KING HITTER POST DRIVER may need to take remedial action if their machine is similar or the same.

Image 1: Example of an older model King Hitter Post Driver, similar to the one involved in this case.

Image 2: Detail of the welded lug which requires the chain to be placed on the cap.

Circumstances

After driving the post the 16 year-old farm worker raised the Monkey Weight and Post Cap as one. To do so requires the chain on the cap to be placed on the lug welded on the Monkey Weight.

The Post Cap dislodged from the lug falling onto the worker's hand.

Investigation

• The Post Cap weighs 15kgs
• The machine is approximately 23 years old.
• The 12mm welded lug was worn almost parallel providing no adequate means to retain the chain.
• A combination of tractor/machine vibration and an insecure connection point is the most probable cause of the Post Cap being dislodged.
• The manufacturer advises that later machines do not have a welded lug on the weight, the design having been modified.
• It is unknown when the manufacturer changed the design because company records were destroyed in a fire.

Recommendations

If you use a King Hitter Post Driver as described, it is recommended you:

• Inspect the lug for wear and tear and modify this contact point to ensure the Post Cap chain is secured.
• Enter this hazard and any similar ones into your hazard register along with your means of hazard control.

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DOL 10509H FEB 08

Issued by the Department of Labour, New Zealand
http://www.osh.dol.govt.nz

No. 31 - February 2008