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Power take-off devices can rip safety out of a farm

COLUMBIA – Donnie Summers of Lathrop, distinctly remembers the day his father’s overalls got caught in a power take-off (PTO) of a silage cutter. The revolving device ripped his coveralls off and even pulled one sock out of his work boots.

Naked and shaken up, he walked down the country lane to his farmhouse. He was one of the lucky ones, says University of Missouri Extension safety specialist Karen Funkenbusch. She says Farm Safety and Health Week, Sept. 21-27, is a good time to review PTO rules.

Since the 1930s, PTOs helped farmers harness the power of tractor engines to drive a variety of implements. The tractor powers a shaft that spins at hundreds of revolutions per minute.

Funkenbusch recently showed how quickly a PTO can grab clothing or hair and wrap it around its revolving shaft. She and other faculty from MU’s College of Agriculture, Food and Natural Resources demonstrated a timer that mimics a PTO. People test their reaction time by hitting a switch to turn the PTO off; a digital readout shows how long it took to shut down the device.

In the time it takes a person with average reaction time to hit the off button, a 540 rpm PTO can wrap the operator around the shaft, Funkenbusch said.

“It is a common misconception that a human being can react fast enough to avoid serious injury,” she said. “Once entangled, there is little a person can do.”

Reaction time slows with age, declining physical condition, use of medication and lack of sleep.

Funkenbusch gives the following advice for the upcoming harvest season:

  • Always pull up long hair and braids when working around equipment. Put hair under a hat for best results. Remove jewelry and earrings when working around PTOs.
  • Don’t wear clothes with loose sleeves, frayed edges or drawstrings. Avoid long shoelaces.
  • Keep safety shields and guards in place, even after repairs have been made.
  • Stay clear of moving parts.
  • Always shut off augers and machinery equipped with belt and chain drives and rotating pulleys.
  • Stop the PTO when dismounting from the tractor.
  • Don’t let children ride on or near a tractor. They can be entangled in the PTO if they slip.
  • Walk around tractors. Never step over a rotating shaft.

To see a demonstration of how quickly you can become entangled, go to For more information about power take-off safety, go to

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