We want to share a little-known fact about your tractor PTO and what you should do about it.
If you do not feel that you understand these steps, or can perform them safely, consult your tractor dealer or local mechanic. Also always consult your tractor owner’s manual for model-specific information.
Onward we go!
The “Fact”
This PTO (Power Take Off) fact is simple, little-known, and crucial to know.
Here it is --- Your tractor PTO is extremely dangerous and can easily cause a major injury.
Sadly, many operators take their PTO for granted.
The Danger
Your PTO is one of the most dangerous power transfer devices on your tractor.
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 can react.
The fast rotation speed, operator error, and the lack of proper guarding makes a PTO a persistent hazard on farms and ranches.
The Injuries
There are a multitude of PTO serious injuries and fatalities every year.
Injuries include:
Severe contusion
Deep cuts
Spine and neck injuries
Dislocations
Broken bones
Scalping
Death
It is not hard to become entangled in a PTO.
Entanglement incidents occur when the operator:
Is unaware that the PTO clutch is engaged.
Does not understand the dangers of the spinning PTO stub.
Deliberately works too close to an unguarded stub shaft that is in motion.
Clothing (pant legs, shoelaces, threads from a jacket, etc…) is easily caught by the spinning shaft. Once they are caught, both the clothing and the operator can quickly wrap around the stub shaft.
The Driveline
A PTO driveline or implement input driveline (IID) is the part of the implement drive shaft that connects to the tractor. If it is unguarded, the entire shaft of the driveline is considered a wrap-point hazard.
Some drivelines have guards covering the straight part of the shaft. This leaves 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. Once 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 creates a tighter wrap.
The Separation
Injuries also 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.
Now, 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. The shaft then becomes 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.
The Safety Solution
The solution is to practice tractor PTO safety.
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 the front joint is secured properly. Replace a damaged master shield immediately.
A tractor PTO driveline shield is made 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, there are other precautions that can reduce your risk of a PTO incident.
They include:
Never step over a rotating shaft.
Ensure that safety decals, such as “Rotating Driveline: Contact can cause death,” are readily visible. Replace all decals that are obscured or incomplete.
Always disengage the PTO and shut off the tractor before dismounting.
Never work on machinery or equipment while the engine is running or is energized.
Keep universal joints in phase.
Do not wear loose-fitting clothing around any PTO-driven equipment.
Tie back any long hair or secure it under a hat before operating the equipment.
Examine the driveline for protruding pins, 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 pre-operation inspection, if the driveline shield is equipped with a tether, ensure that the tether is attached and in good condition. Also make sure that the driveline shield rotates freely on its bearings.
Do not switch drivelines between machines.
To reduce driveline stress and separation --- position the tractor’s drawbar appropriately for each piece of machinery.
Reduce the 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.
Hopefully, this short article helped you better understand the dangers of your tractor PTO and how to stay safer.
If you need any further help or have any questions about safety, tractors, or anything else, please contact your dealer, local mechanic, or call us at 602-734-9944. Please ask about our current new and used tractor supply.
Tractor Ranch - #1 Tractor Dealer in Arizona. We sell and service most major brands of tractors including Yanmar, Kubota, John Deere, TYM, Mahindra, Kioti, Case, New Holland, Massey Ferguson, Ford, Deutz, Case IH, Farmall, International Harvester, Branson Tractors, LS, Shibura, Claas Tractor, McCormick Tractors, Valtra, Solis, YTO, Montana, and Nortrac.
