Power Take-Off Safety

Using PTO Implements

Using PTO Implements

(Source: Pennsylvania State Ag Safety and Health)


Use the following format to cite this article:

Power take-off safety. (2012) Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice. Retrieved from http://www.extension.org/pages/66324/power-take-off-safety.


A power take-off (PTO) shaft transfers mechanical power from a tractor to an implement (shown above). Some PTO-driven equipment is operated from the tractor seat, but many types of farm equipment, such as elevators, grain augers, silage blowers, and so on, are operated in a stationary position, enabling an operator to leave the tractor and move in the vicinity of the implement.

A PTO shaft rotates at a speed of either 540 rpm (9 rotations per second) or 1,000 rpm (16.6 rotations per second). At these speeds, a person’s limb can be pulled into and wrapped around a PTO stub or driveline shaft several times before the person, even a person with extremely fast reflexes, can react. The fast rotation speed, operator error, and lack of proper guarding make PTOs a persistent hazard on farms and ranches.

Injuries that can be sustained from PTO incidents include severe contusion, cuts, spinal and neck injuries, dislocations, broken bones, and scalping. Some incidents can result in fatalities.

PTO Hazards

The main PTO hazards involve the PTO stub and driveline.

PTO Stub

The tractor’s stub output shaft, referred to as a PTO stub, transfers power from the tractor through a drive shaft to the implement or PTO-driven machine. The PTO stub rotates at rate of 540 or 1,000 rpm, and most incidents involving the PTO stub are entanglement incidents.

Entanglement incidents can occur when the operator is unaware that the PTO clutch is engaged, when the operator does not understand the dangers of the spinning PTO stub, or when the operator deliberately works close to an unguarded stub shaft that is in motion. Clothing, such as a pant leg, shoelace, thread from a jacket, and so on, is easily caught by the spinning shaft. Once caught, both the clothing and the wearer can quickly wrap around the stub shaft.

PTO Driveline

A PTO driveline or implement input driveline (IID) is the part of the implement drive shaft that connects to the tractor. When unguarded, the entire shaft of the driveline is considered a wrap-point hazard. Some drivelines have guards covering the straight part of the shaft, leaving the universal joints, PTO coupling, and the rear connector, or implement input connection (IIC), as wrap-point hazards. Clothing can catch on and wrap around the driveline. When clothing is caught on the driveline, the tension on the clothing from the driveline pulls the person toward and around the shaft. When a person caught in the driveline instinctively tries to pull away from wrap hazard, he or she actually creates a tighter wrap.

Driveline Separation

In addition to injuries caused by entanglement incidents with the PTO stub and driveline, injuries can occur when shafts separate while the tractor’s PTO is engaged. The IID shaft telescopes, meaning that one part of the shaft slides into another. The sliding sleeve on the shaft allows for easy hitching of PTO-powered machines to tractors and allows telescopic movement when the machine turns or is operated on uneven ground. If the IID is attached to a tractor by only the PTO stub, the tractor can pull apart the IID shaft. If this occurs and the PTO is engaged, the tractor shaft can swing wildly, striking anyone in range and possibly breaking a locking pin, allowing the shaft to become a projectile. This type of incident is not common, but it is more likely to occur with three-point hitched equipment that is not properly mounted or aligned.

Safety Recommendations

The first line of defense to prevent a PTO entanglement incident is to make sure that your tractor and machinery have the proper shields.

PTO Master Shield

PTO Guard

(PTO Master Shield. Source: Pennsylvania State University. Agricultural Safety and Health)

The above photo shows a master shield that covers and extends over the tractor PTO stub on three sides. The master shield provides protection from the PTO stub and front joint of the drive shaft when the PTO stub is connected to the tractor.

Before operating PTO-powered machinery, always make sure that the master shield for the tractor PTO stub and front joint is secured properly. Replace a damaged master shield immediately.

Driveline Shield

PT Shielding Photo

(PTO Master Shield and Driveline Shield. Source: University of Georgia. College of Agricultural and Environmental Sciences)

A PTO driveline shield (shown above) is constructed of plastic or metal and completely encloses the shaft. The bell-shaped ends cover the universal joints on the shaft. The shield is mounted on bearings so that it rotates with the shaft but stops spinning when a person touches it.

Check the driveline shield by spinning it to make sure that it rotates freely. If the shield is damaged or does not rotate independently, it does not provide protection and must be replaced.

Additional Safety Precautions

In addition to having the proper shields in place, taking the following precautions can reduce your risk of a PTO incident:

  • Never step over a rotating shaft.
  • Do not wear loose fitting clothing around PTO-driven equipment.
  • Tie back long hair or secure it under a hat before operating equipment.
  • Ensure that safety decals, such as “Rotating Driveline: Contact can cause death,” are readily visible. Replace decals that are obscured or incomplete.
  • Always disengage the PTO and shut off the tractor before dismounting the tractor.
  • Never work on machinery or equipment while the engine is running or is energized.
  • Keep universal joints in phase.
  • Do not switch drivelines between machines.
  • To reduce driveline stress and separation, position the tractor’s drawbar appropriately for each piece of machinery.
  • Reduce PTO shaft abuse by avoiding tight turns, reducing excessive telescoping, engaging power to the shaft gradually, and avoiding over-tightening the slip clutch on PTO-driven machines.
  • Examine the driveline for protruding pins or bolts and debris such as mud that has dried onto the driveline shield. Clothing snags easily on such protrusions, resulting in entanglement incidents.
  • As part of the preoperation inspection, if the driveline shield is equipped with a tether, ensure that the tether is attached and in good condition and that the driveline shield rotates freely on its bearings.


Click HERE to view a video by the Alabama Cooperative Extension that explains how to install and maintain a shaft cover on a tractor PTO.

Click HERE to view and order safety decals for your PTO driveline from the Agricultural Driveline Manufacturers Association (ADMA).


Use the following format to cite this article:


Power take-off safety. (2012) Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice. Retrieved from http://www.extension.org/pages/66324/power-take-off-safety.



American Society of Agricultural and Biological Engineers. (2009) ANSI/ASABE S604. Safety for Power Take-off (PTO), Implement Input Driveline (IID), Implement Input Connection (IIC), and Auxiliary Power Take-off (aux. PTO) for Agricultural Field Equipment. St. Joseph, MI. Retrieved from http://elibrary.asabe.org.

FARM-HAT. (2010) Pennsylvania State University Department of Agricultural and Biological Engineering, Agricultural Safety and Health. Retrieved from http://www.agsafety.psu.edu/farmhat/.

Harshman, W., Yoder, A., Hilton, J., & Murphy, D. (2004) Using power take-off (PTO) implements. HOSTA task sheet 5.4.1. Retrieved from http://articles.extension.org/sites/default/files/Version%203.%20January….

Murphy, D. (2014) Power take-off (PTO) safety. Penn State College of Agricultural Sciences Cooperative Extension. Retrieved from https://extension.psu.edu/power-take-off-pto-safety.

Safety decal. (2006) Agricultural Driveline Manufacturers Association. Retrieved from http://admausa.com/SafetyResources/SafetyDecal.php.


Reviewed and Summarized by:
Linda M. Fetzer, Pennsylvania State University – lmf8@psu.edu
Glen Blahey, Canadian Agricultural Safety Association  GBlahey@casa-acsa.ca
Jesse Laprade, Auburn University  laprajc@auburn.edu
Dennis J. Murphy, Pennsylvania State University (Has since retired)
Aaron M. Yoder, University of Nebraska Medical Center – aaron.yoder@unmc.edu


Safety Recommendations When Baling and Handling Round Bales

Round Bale in Field

(Source: Pennsylvania State University. Agricultural Safety and Health)


Use the following format to cite this article:

Safety Recommendations When Baling and Handling Round Bales. (2012) Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice. Retrieved from http://www.extension.org/pages/64301/safety-recommendations-when-baling-and-handling-round-bales.


When baling and handling large round bales, you must recognize and understand potential hazards and follow the manufacturer’s operating recommendations for each piece of equipment you use.

Using a Round Baler

The round baler is a complex machine with multiple moving parts, and an entanglement incident could lead to costly repair bills, injury, or death. Prior to using the baler each season, you must:

  • thoroughly inspect it,
  • make any needed repairs, and 
  • review all of the safety precautions in the owner’s manual.

The size and rated power of the tractor you use with your baler must meet the manufacturer’s requirements for towing and powering the baler.

Safety Recommendations

  • Make sure that safety locks are in place when working on the baler while the bale chamber is open.
  • When operating the baler, do not leave the tractor seat until the power take-off (PTO) is disengaged and all moving parts have stopped.
  • Ensure that all the original shields are in place on the power shafts and other moving parts of both the tractor and baler.
  • Because balers produce flammable dust and are susceptible to overheating due to friction, equip your tractor with a 10-pound dry chemical (ABC) fire extinguisher.
  • Eject the bales at an angle perpendicular to the slope to reduce the risk of a bale rolling down the incline.
  • When baling on uneven or hilly terrain, travel slowly and avoid holes and drop-offs. A round baler has a high center of gravity and could tip sideways if a wheel goes into a ditch or hole.
  • Avoid sharp turns with a baler because the tractor wheels might hit the tongue of the baler. 
  • Refer to the owner’s manual of the baler for additional safety information related to the machine you are using.

Handling Bales

Many producers move bales in the field with front-end loaders. The recommended practice for moving bales with a front-end loader is to remove the bucket and use an attachment designed to handle round bales, such as a grapple hook or bale spear. Using a grapple hook or spear on your front-end loader reduces the potential for the bale to roll back onto the loader arms or operator. Click here to watch a video by Mississippi State University about the danger of lifting unsecured loads with a front-end loader.

Be certain that both the tractor and the attachment are able to safely handle the weight and size of your round bales. The lifting mechanism used to move the bales should have a working load rating that exceeds the size of the bales.

The center of gravity on a tractor changes when it is carrying a bale. Producers tend to lift the load to increase visibility. This action raises the center of gravity and places the tractor at increased risk for a side overturn. The risk of a side overturn also increases when traction is lost because the tractor is operating on rough terrain or wet ground.

When using a rear-mounted three-point lift to move round bales, do not lift bales too high. The center of gravity could shift to the rear of the tractor and cause the front of the tractor to rise. If the front of the tractor rises too much, the front tires lose stability, and steering is impaired. Hauling bales simultaneously with a front-end loader and rear-mounted attachment can reduce the stability problem, but you must take care not to exceed the weight limit for the loader tractor’s tire capacity. 

Safety Recommendations

  • Avoid overhead wires when you are moving bales with a front-end loader. Keep the bale close to the ground.
  • Use additional weight (within the load capacity of the tires) on the front or rear end of the tractor to ensure stability.
  • Relieve the hydraulic pressure before disconnecting all hydraulic lines. Examine the lines for leaks and malfunctioning parts.
  • When moving bales, use a tractor that is equipped with a rollover protective structure (ROPS), and always buckle the seat belt.

Hauling Bales

Specialized bale wagons and trailers that carry multiple bales at a time can save time and reduce the risk of overturns and of overloading a tractor’s hydraulic system.

Safety Recommendations

  • When using a wagon or trailer to haul bales, choose a tractor that can maneuver and stop a wagon or trailer carrying the weight of the bales.
  • Ensure that the wagon or trailer is properly hitched to the tractor’s drawbar by using a safety pin and a safety chain. 
  • Properly secure the bales on the wagon or trailer by using straps that have a tensile strength of one-and-half times the weight of the load.
  • When transporting round bales on a public roadway, remember to follow all traffic laws related to wide loads. The trailer or wagon should be highly visible and equipped with a slow-moving vehicle (SMV) emblem, reflectors, and warning lights.



Use the following format to cite this article:

Safety Recommendations When Baling and Handling Round Bales. (2012) Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice. Retrieved from http://www.extension.org/pages/64301/safety-recommendations-when-baling-and-handling-round-bales.


Grisso, R., Cundiff, J., Stone, B., and Smith, R. (2002) Large round bale safety. Virginia Cooperative Extension. Retrieved from http://www.pubs.ext.vt.edu/442/442-455/442-455_pdf.pdf.

Grisso, R., Fike, J., Ohanehi, D. & Perumpral, J. (2014). Management Tips for Round Bale Hay Harvesting, Moving, and Storage. Virginia Cooperative Extension. Retrieved from http://pubs.ext.vt.edu/442/442-454/442-454.html.


Reviewers, Contributors, and Summarized by:
Willard Downs, University of Missouri  Willard@missouri.edu
Linda M. Fetzer, Pennsylvania State University – lmf8@psu.edu
Dennis J. Murphy, Pennsylvania State University – djm13@psu.edu
Michael Pate, Utah State University  michael.pate@usu.edu
Aaron Yoder, University of Nebraska Medical Center – aaron.yoder@unmc.edu