Combines are one of the largest pieces of harvest equipment and operating them safely can greatly enhance harvest efficiency.
John Long, Assistant Professor & Extension Ag Engineer at Oklahoma State University Biosystems and Agricultural Engineering department, says focusing on safety during harvest can help farmers avoid bodily harm and complete harvest in a more efficient way.
“Most farmers only use their combines once, maybe twice, each year,” Long says. “We may tend to think of using a combine like riding a bike. Once you learn it you never forget. But combines are large, complex machines. Those with large headers need a lot of area to maneuver and they don’t drive in the same way tractors do. Combines swing quickly and operators need to be very aware of where they’re at and what’s around them.”
Long recommends that experienced combine operators thoroughly review combine manuals prior to harvest to refresh their understanding of the machine’s controls, features and safety precautions. Operators using a combine for the first time should allow ample time to thoroughly read the machine’s manual and become thoroughly familiar with operating instructions and instructions for safe operation.
Well before harvest begins, combine operators are urged to clean the combine to remove any field residue, oil and grease buildup and detect and clear any rodent infestation. Inspecting nuts, screws, shields and sheet metal can help identify any need for replacing or maintaining these parts. This practice helps avoid machine breakdown and can be a key part in preventing accidents during harvest.
“By going through the combine prior to harvest and checking all wearable parts such as belts and chains, you can avoid downtime and added harvest pressure,” Long says. “Typically, combines run for long hours at a time during harvest, which pushes engines and all the mechanical parts of the machine. A pre-harvest check of all these parts can help spot any parts at risk for failing during harvest. Repairing or replacing those parts is much easier when you’re in a controlled environment in a shop using air tools than laying on your back under the machine while you’re in the field.”
Long cautions operators to thoroughly understand the safety guidelines related to getting under their combine. Even while a combine is in the shop, it’s unsafe to rely 100% on the combine’s hydraulic system if you’re underneath the machine.
“Always use safety blocks if you’re working under a combine,” Long says. “Hydraulic systems can fail, so make sure you have a backup system in place. Of course, it’s never safe to have the machine running while you work on it. And you need to give it several minutes for all those machine parts to stop moving before you work on it. Many of those parts have a lot of momentum and take time to slow down and stop.”
In addition to all the motion found in a combine, repair can involve many “pinch points,” any place where a person can be caught between two moving parts or a moving part and a stationary part. Shear points are wherever edges of two moving parts move across each other.
Wrap points are places where the machine spins at high speed. Hands, limbs, loose clothing or long hair can become entangled in rotating parts, leading to serious or life threatening injury.
Pull-in points on a machine are those places where the machine pulls material into the machine for further processing. Injury in these areas typically occur when someone tries to remove material from the machine or tries feeding material by hand while the machine is running. It’s critical to shut a machine off before attempting to remove material.
“The biggest hazard in regard to combines is anything that moves, including the header,” Long says. “Moving combine parts are usually shielded. Make sure those shields are in place or are repaired or replaced if they’re damaged.”
Each year, combine fires cause disastrous damage. In most cases, operators manage to escape with little or no injury. However, the economic loss of the combine and setback it causes to harvest activities are very detrimental.
“A small hot spot on the combine can quickly spiral into a full blown fire,” Long says. “To avoid fire, look for engine heat. At least 75% of combine fires are initiated in the engine area.”
Fire requires three elements to burn: oxygen, material to burn and a heat source. Steps to farm machinery fire prevention include keeping the combine clean of possible ignitable materials and eliminating heat sources with enough energy to start a fire.
During harvest, it’s recommended to clean the engine compartment and exhaust at least once per day. During periods of heavy operation, more frequent cleaning may be necessary, due to the dusty environment where it’s used. Compressed air is a good tool for removing dust and chaff and a high pressure washer will remove a build up of grease, oil and hydraulic fluids. It’s important to wear an N95 respirator to protect your lungs from this dust and debris.
“Other places where fire can start are worn belts that slip and cause friction and build up heat,” Long says. “Leaking grease or lubricant can also burst into flame if they’re hot enough.”
Long encourages use of an infrared thermometer that can quickly scan potential hot points on the combine and provide a temperature reading.
“The gun can be used to obtain a temperature reading on combine bearings that are well over the operator’s head,” Long says. “It takes just a few minutes to scan those potential hot spots and know for certain you’re not in danger of igniting a fire.”
In refueling, newer combines using diesel fuel pose a lesser threat of a fuel fire, but it’s recommended to allow the engine to cool to some degree before refueling. Older combines, running on gasoline, are more susceptible to fire due to the flammability of the fuel and its vapors.
“In the event of a fuel spill, clean it up as much as possible,” Long says. “You don’t want the combine sitting over any area where fuel was spilled because that sets you up for igniting a fire.”
A pre-harvest combine check up must include GPS (global positioning systems) and calibration of any other technology included in the combine, such as yield monitors. Even though calibration of this type of equipment is usually taken care of at the time of purchase, it requires regular recalibration. Consult the combine manual for calibration instructions specific to the technology brand.
While it isn’t feasible to keep a wide range of replacement parts on hand, maintaining supplies such as fuel and oil filters, belts and chains can help avoid major harvest downtime.
“Some parts, such as belts and chains, parts known to fail at some point, should be replaced each year prior to failure, minimizing any economic impact of a breakdown,” Long says.
Safety steps sometimes overlooked at harvest time are identification of washouts, ditches or other obstacles and areas of the field where terrain is impassable or uneven. Since tall corn can obscure many features of a field, marking difficult terrain with a flag can help operators safely navigate the area(s).
“Dropping the combine into a ditch could cause significant damage to both the combine and head,” Long says. “When operators are fatigued and covering a lot of ground in a short time, it’s easy to overlook these kinds of obstacles.”
In checking the combine’s hydraulic system, Long advises use of a piece of cardboard to search for any leaks, since the hydraulic fluid PSI (pounds-per-square-inch) is high enough to cause a skin laceration or injury to soft tissue.
“It’s the same type of pressure used in waterjet cutters that use a high pressure stream to pierce metal,” Long says. “With the cardboard or other type of material catching a spray of fluid, you can quickly detect a leak or drippage. When the combine is sitting on a concrete base, that’s also a good time to check underneath it for any indication of fluid leaks.”
Ideally, moving from one field to the next should be completed during daylight hours. If an operator needs to drive down a highway or side road after dark, use of the most lighting possible helps reduce potential for accidents. Even with significant lighting, some drivers may not recognize what type of equipment they’re coming up on until they’re right there.
“It’s always preferable to move with the header off and in some cases, the widest combines have no choice in that because the header takes up both lanes on a highway,” Long says. “Make sure everything on the combine is in stowed position and all grain is dumped in grain carts or trucks. Combines have a high center of gravity and traveling with grain in the bin increases the chances of tipping on uneven ground or when entering onto a roadway.”
Pre-harvest planning begins at planting time, when producers develop a weed management strategy. Minimizing weed issues means problems related to weeds wrapping around rotating parts and plugging are greatly reduced, too.
“A weed-free crop means less likelihood that the combine will plug,” Long says. “In a weedy field, it’s not uncommon for a producer to become frustrated with the plugging and look for ways to cut corners to keep harvest moving. That’s when you get into issues of human error.
“Fatigue can cause us to make decisions we wouldn’t otherwise choose,” he adds. “Staying alert and doing everything you can to enhance safety will make harvest more safe, efficient and more productive.”