A power take-off (PTO) is the primary method of transferring power from the engine of a tractor to the implements. The date back to the 1800s, and have been the primary method for power transfer for almost 100 years. Unfortunately, the way they operate also makes them one of the most dangerous parts of any type of farm equipment. A PTO shaft can rotate at a speed of up to 18 revolutions per second or faster, leaving very little time to react. While we know that everyone has heard much of this before, we feel it never hurts to provide a regular reminder of safety and safe conduct around PTOs.
Types of PTO Accidents
There are two main types of PTO accidents that occur. One of them is caused by driveline separation, where the implement input driveline (IID) separates from the implement or snaps in half. The PTO shaft will then be propelled through the air, or swung around at the rear of the tractor, able to strike bystanders with lethal force. If the PTO shatters, or swings and destroys the rear end of the tractor, it can also send dangerous shrapnel through the air.
The second, most common accident that occurs involving PTOs happens through entanglement with the PTO shaft while it is running. This can be quick, and it doesn’t take much – a single thread can catch and pull a person in. This can occur when clothing, hair, dangling jewelry, or even a bootlace that is just a bit too long gets too close to the shaft. When the person instinctively pulls away from the driveline, it can create an even tighter wrap around the driveline due to increasing the tension. As a person is in, this can lead to scalping, breaking bones, pulling off skin, loss of limbs and fatalities.
There are a number of safety devices and processes you can use as safeguards around the PTO stub and shaft.
- A master shield should cover the exposed PTO stub on the tractor itself. This shield provides protection from being caught up in the spinning stub when there is no driveline connected. It also provides protection from the spinning front joint of the drive shaft, a knuckle that can catch clothing very easily. Finally, it can help to keep a driveline from flying up into the air should it become uncoupled while in use, instead directing the shaft downwards.
- A driveline shield is a plastic and metal shield that sits over the shaft itself. Sitting on bearings, it will spin with the shaft but will stop if there is contact with it, while allowing the driveline to continue spinning. This shield provides great protection, but cannot be counted on for full protection, especially if cracked or not rotating independently. Test your driveline shield before use by spinning it without the driveline being engaged. If you can’t spin it on your own, it will not stop spinning if it you come into contact with it when the PTO is engaged.
- Keep your PTO shaft clean and well-maintained – a dirty or dinged PTO has more of a chance of catching hair or loose clothing. Even dried mud can catch wayward materials and hook it around a spinning shaft.
- When a PTO is in use while the tractor is supposed to be stationary, make sure the tractor is in neutral or park, and the parking brake is applied.
- Always position the drawbar of your tractor appropriately depending on the piece of equipment – this will reduce stress and strain on the driveline and reduce the chance of driveline breaking or separation.
- Regular inspection of all PTO components is the best safeguard you can have – you will notice when something is wrong before your tractor and attachments go out into the field.
PTO Safety Precautions
The avoidance of the spinning PTO is the key to safety. Don’t reach across it, step across it, or get too close to it during operation. Being mindful around a spinning PTO is the best way to avoid dangers, but there are additional steps you can take:
- Do not wear loose clothing around a spinning PTO.
- Securely tie back any long hair – we can’t emphasize the securely part.
- Do not wear loose jewelry.
- Don’t go near the PTO until it has stopped rotating entirely.
- Make sure to have proper warnings and safety decals and make sure they are easily visible.
- Make sure to keep all universal joints in phase.
- Reduce the amount of stress on the PTO by avoiding tight turns, limiting telescoping of the driveline, and easing the driveline into engagement instead of releasing the PTO clutch rapidly, causing the PTO to jerk into action.
PTO incidents are one of the oldest known tractor dangers, but they continue to claim numerous victims every year. Accidents can happen, but you should always do your best to avoid them, and to bring their chances of happening down to the lowest percentage possible. Make sure to educate everyone working around your equipment in proper conduct around PTOs, and make sure to keep safety in mind when you are around a PTO, and stay safe and sound.