following script can be used to deliver a 15-minute training
session to employees. It would be a good idea to make the
presentation while standing in front of a tractor with a PTO-driven
piece of equipment attached. You can point out hazards and
safety features on the machinery. ( Make sure that all shielding
is in place and in good condition! )
The text emphasizes the most important points related to PTO
safety. It is suggested that you try to stay strictly on topic.
Obviously, you will need to be prepared to answer questions.
guards in shields must be in place and in good repair.
shut down power before servicing or unplugging equipment.
close-fitting clothes and keep long hair covered when
working with power equipment.
A 540 PTO shaft travels more than two meters in less than a
second. Anything caught by that spinning shaft-clothes, shoelaces,
hair-will instantly be wrapped up. No wonder that PTO accidents
nearly always result in devastating injury or death.
PTO entanglement most often occurs when people try to make repairs
while equipment is operating. Other victims have been caught
while stepping over or onto rotating shafts.
This leads to the cardinal rule of PTO safety Never
attempt to repair, adjust, or unplug equipment with the PTO
engaged! You can't get caught by a shaft that isn't turning.
Proper shielding all-important
All PTO shielding must be correctly installed and properly maintained
to prevent injury in the event of accidental contact. You should
refuse to use a machine with damaged or missing PTO shields.
Let's start at the tractor, and work our way back to the driven
Your PTO safety checklist
- The tractor's master shield prevents contact with the
stub shaft and the front universal joint of the attached
machine's driveline. Never operate a tractor with a missing
or damaged master shield !
- Tubular shields completely enclose the power shaft of
a PTO-operated machine. This integral shield rotates on
bearings, independently of the power shaft. Bearings must
be in top condition to ensure that the shield will stop
spinning if accidentally contacted.
- Cones used to cover the universal joints at each end
of the power shaft have been greatly improved in recent
years. Their flexible nature makes hook-up easier, while
providing greater protective cover than earlier, bell-shaped
- The stub shaft on the driven machine should also be covered
by shielding. Just like the tractor's master shield, this
prevents accidental U-joint contact.
- With the PTO disengaged and the tractor engine shut
off, check the condition of the entire PTO shielding
system. Look for nicks, dents, or bent components. Test
for free movement of the tubular shield on its bearings.
- If any shielding component is damaged or missing, or
if you feel it doesn't provide adequate protection, talk
to your employer about replacing the defective items.
- Before attaching PTO-powered equipment, confirm that
the tractor drawbar is adjusted to the length specified
in the driven machines manual. This ensures that the telescoping
power shaft and shield will stay together when they lengthen.
If a PTO shaft separates in operation, the tractor-driven
end will swing violently, and could cause equipment damage
and operator injury.
Your PTO safety checklist As with all aspects of farm machinery
operation, you must be constantly alert to prevent PTO accidents.
Follow these steps to avoid PTO entanglement.
Make shutdown a habit
- Most importantly, always disengage the PTO, shut off
the tractor engine, and remove the keys before leaving
the tractor seat. You can't be injured by the PTO or other
machine parts if the driveline isn't rotating. Taking the
keys prevents unexpected startup by another person while
you are making repairs or adjusting the machinery.
- Keep the tractor's master shield in place at all times.
The PTO could be accidentally engaged when no driveline
is attached. An exposed, rotating tractor stub shaft will
aggressively grab and wrap anything it contacts.
- Check frequently to make sure that PTO shielding is in
good condition (with power disengaged, of course). Damaged
shields or bearings should be repaired or replaced before
the equipment is operated again.
- Never step across a rotating PTO shaft! Some equipment
must be operated in a stationary location, with you working
nearby (for example, grain augers, forage blowers, generators,
etc.) Always walk around such machinery. Safety devices
are usually reliable, but could malfunction. Take extra
car~ if the ground is muddy or icey.
- Dress for safety. Wear close-fitting clothes and
keep long hair covered. Raggy old coats and long boot laces
can easily be grabbed by rotating parts.
Additional spinning shafts are often used to transfer power
to machine components. Just like a PTO shaft, these can entangle
you in an instant. The same principles apply when it comes to
safety around any rotating shaft.
Again, it must be emphasized:
Always disengage the PTO, shut off the tractor engine, and remove
the keys before leaving the tractor seat!
Are there any questions?
Finally, let's take a moment to review some of the "Do's" and
"Don'ts" of PTO safety.
shut down equipment before making repairs or adjustments.
check the condition of all PTO shielding components
close-fitting clothes and tie up long hair when working
wit power equipment
walk around operating equipment.
the keys in the tractor ignition while making repairs
equipment with missing or damaged PTO shields.
raggy old coats, loose laces, or anything else that
could become entangled.
step onto an across a PTO shaft.
The information and recommendations contained in this publication
are believed to be reliable and representative of contemporary
expert opinion on the subject material. The Farm Safety Association
Inc. does not guarantee absolute accuracy or sufficiency of
subject material, nor can it accept responsibility for health
and safety recommendations that may have been omitted due
to particular and exceptional conditions and circumstances.
Copyright © 2002
Farm Safety Association Inc.
22-340 Woodlawn Road West, Guelph, Ontario N1H 7K6 (519) 823-5600.
Disclaimer and Reproduction Information: Information in
NASD does not represent NIOSH policy. Information included in
NASD appears by permission of the author and/or copyright holder.