SO WHAT'S THAT HAVE TO DO WITH CUTTING GRASS?
More than you might think. Ergonomics is a major consideration in the design and engineering of today's mowers and grounds care equipment. For good reason. Workers are more efficient, more attentive and more productive when they are less fatigued and have to strain less to operate equipment.
Still, landscape operations are among the highest industries for injury and illness, according to figures compiled by the Occupational Safety and Health Administration (OSHA). In fact, OSHA and the Associated Landscape Contractors of America (ALCA) recently joined forces in a program to promote worker safety in large and small landscape businesses.
If you manage employees, you no doubt are well aware of the costs for Workers Compensation Insurance. Even with the advances in equipment design, Nebraska (for example) had more than 180 claims filed with the state's Workers' Compensation Court last year, under the general category of “grounds care workers.” Federated Mutual Insurance Company did a major study of worker compensation injuries in 2002 and 2003 for equipment dealers. By far, the biggest cause of losses was strain injuries — lifting, twisting, machinery use, repetitive motion, etc.
Several years ago, British researchers conducted a laboratory study to evaluate 10 different lawn mowers for ease of starting, operating controls and handling. They randomly selected 99 paid subjects (50 male, 49 female), ranging in age from 14 to 71 but all with prior lawn mower experience. Although all the mowers had high startability rates (90-97 percent), 70 percent of them were perceived as less than easy to start and controls were less than easy to operate on 90 percent of the mowers. About 95 percent of the subjects could not identify the safety control lever or the self-propel control on one lawn mower.
Darrell Hinklin, supervisor of industrial design for Toro, says he can remember the days when manufacturers designed tractors and riding mowers to do the work, but the operator almost had to be lifted into place, or climb over a tire, hitch or attachment to get into the seat. Thank goodness those kinds of problems are disappearing as designers and engineers learn more about fitting equipment to people.
“Now,” says Hinklin, “ergonomics factors are designed into equipment right from the beginning.” Most mower manufacturers today take great pains to make their equipment as operator-friendly as possible. Even walk-behind mowers now come with features that make for easier control, and adjustments that enable operators of different sizes to comfortably run the mowers.
Toro, for example, designs their riding mowers to fit the 95 percentile for male operators and all but the smallest 5 percentile of female operators. In other words, an NBA all-star player might feel cramped if he climbed into the seat of a new Toro Z, but just about anyone else would fit okay. And a petite gymnast might have to stretch some to reach all the controls, but most females would be comfortable operating the machine.
“These size parameters are based on world population figures, not just the U.S.,” Hinklin says, “because of our international sales and because many operators in the U.S. today come from Hispanic and other backgrounds.”
Hinklin says the objective today is to make the operator/machine interface as seamless as possible. “When a mower is run for eight or more hours per day, the operator will do a better job if he or she is more comfortable. And, the operator who is more satisfied with his equipment tends to take better care of it.”
Toro's industrial designers have focused on both the operator environment and mower control features, according to Hinklin. “We've engineered seats for added comfort, of course, but they also are designed to be more ‘capturing’ of the operator's frame, to enhance his stability when mowing slopes and sidehills.”
Both seat cushioning and suspension have been improved, concentrating on high-pressure areas like lower backs and hips. “We specify seat backs that are 15 to 18 inches high on most riders,” he says. “Sometimes, limited space on smaller units dictates seat dimensions, but we aim for the most comfort possible. When you see an operator come to work in the morning with his own seat cushion or back cushion, it generally means there is some room for improvement in the factory seat.”
Hinklin says one of the challenges of today's zero-turn mowers is that the operator is essentially positioned right over the rear axle. “This can mean a rougher ride and somewhat of a ‘pounding’ effect on the operator. It's something we take into account in our seat suspension and cushioning.”
There has been a definite trend to “softer feel controls,” says Hinklin. “It continues to evolve, but softer steering wheels, knobs, levers, etc. are more conforming to the operator's hands, plus providing better gripping power for safer operation.” Manufacturers are tending more to “bunched” controls where nearly everything is within easy reach and all in the same general area. “Based on our market research, we even moved the control panel gauges toward the right, closer to the hand controls.”
Kubota has incorporated many ergonomic features from their tractor designs into their ZTR mowers, says James Burnside, product manager for Kubota's commercial turf products. Kubota offers three diesel zero-turn models and recently introduced two gas-engine models. “We surveyed both customers and dealers, then built prototypes for use by commercial cutters before we arrived at our final designs,” he says.
“We've incorporated features like foot-operated hydraulic deck lift and hydraulic clutches, with features like neutral between forward and reverse for smoother operation. We've added seats that can be adjusted for softer or harder feel — with armrests for more comfort. We've added oscillating front axles for better hillside tracking.”
Mower components are more fully integrated because Kubota, according to Burnside, builds all components, except the Kohler gas engines. “Hydraulics, transmission, diesel engines are all Kubota design and engineered to work together. We've recently changed the operator platforms to minimize obstructions for the operator getting on and off the machine, too.”
Gilbert Peña says most manufacturers today design mower ergonomics for versatility. Peña, group brand marketing manager, commercial mowing, with John Deere Worldwide Commercial & Consumer Equipment Division, says commercial mowers may be used by several different people of varying height and weight, so everything that can be adjustable should be made that way — seat position, suspension, steering column, etc.
Seats used to be one-size-fits-all, no frills. Now, seats often adjust fore and aft to accommodate operators of varying height, plus they have better cushioning, spring suspension and usually armrests, says Peña. “Deere was one of the first to centralize controls for more convenient operation, too. We moved them to the right side, starting three years ago. Before, some were on the right, some on the left, some between the operator's legs.”
Deere uses foot controls for raising and lowering cutting decks, along with a right-side dial for setting cutting height in ¼-inch increments. “It just makes sense for the operator to use the strength of his or her leg to raise the deck, instead of straining to pull a hand lever,” says Peña.
Zero-turn mowers are the fastest growing industry segment these days and many of the ergonomics improvements have been made on these models. Walker Manufacturing takes a different approach to its ZTR design with its out-front deck position. “Out-front decks allow the operator to sit lower (as much as 8 to 12 inches lower compared to some mid-mount models),” says Tim Cromley, marketing manager for Walker. “Besides the added stability with the lower center of gravity, the operator has a better view of the mower deck. He doesn't have to strain his neck to look straight down to see the deck. The out-front deck allows for better close-in trimming under trees and shrubs, too.”
Walker uses a combination of a forward speed control and steering levers for mower operation. “The forward speed control is handy, right beside the seat, and controls only ground speed,” Cromley says. “The steering levers are actuated with just finger-tip pressure, and are used to slow the mower for turns. For straightaway mowing, this isn't a big deal, but for close-in maneuvering around flower beds, shrubs or trees, the sensitive finger-tip control really allows precise steering.”
A PEEK INTO THE FUTURE
The manufacturers we visited with all said that ergonomics is continuing to evolve for mowers as well as other grounds equipment. Undoubtedly, new and improved refinements will be made in mower seats, operator controls, convenience features, etc.
Toro's Darrell Hinklin says there is increasing use of symbols and “pictographs” to instruct operators on control and safety features. “Anymore, printed instructions often have to be in two or more languages. It's much simpler when manufacturers can apply stickers or decals with illustrations and symbols to illustrate correct mower operation and safety precautions.”
Hinklin says mowers will continue to incorporate more “nice” features like beverage holders, spaces for radio and cell phone, storage compartments for jackets or sweatshirts, etc. Noise reduction will be a continuing focus, too. Already, manufacturers incorporate hoods and engine covers designed to help soften engine noise. “We've actually gotten to the point on some mowers where engine noise has been mitigated enough that the deck and blades are the noisiest part of the operation,” he says. “We keep working on ways to reduce that noise, but it's not a simple task.”
Hinklin says it won't be long before some mowers come equipped with “joysticks” that can control up to six different functions with one lever. “We're seeing it already in farm equipment and material handling equipment,” he says. “Manufacturers are incorporating electronics more and more into mowing equipment. With more sophisticated switching controls, combining operations into some kind of joystick will be possible.”
Gary Burchfield is a freelance writer who lives in Lincoln, Neb.
ERGONOMICS OF WALK-BEHIND MOWERS
Ergonomics have taken a high priority with walk-behind mowers, as well. Most of today's walk-behinds have adjustable handles, to allow for different operators. Honda took it an additional step by increasing the tube diameter of the handlebar on its new HRX series mowers, “to provide a more natural hand grip for operators,” says Sage Marie, director of public relations for Honda Power Equipment.
Honda, Toro, MTD and some others offer variable speed control features that adjust mower speed to the operator's walking speed — and changes as the operator slows or walks faster. Troy-Bilt calls it “Smart Speed,” Toro's version is the “Personal Pace System” and Honda's HRX offers a “Cruise Control” Hydrostatic Transmission with infinite speeds from 0 to 4 mph.
Walk-behind operator controls have been improved and simplified, much like riding mower improvements. Husqvarna's trademarked feature called “Easy Touch System” positions operator controls in an easier-to-reach and more efficient control center.
Ergonomics, by definition, is the branch of science that aims to learn about human abilities and limitations and then apply that knowledge to improve people's interaction with products, systems and environments.
The science of ergonomics grew out of World War II, when new and improved systems were rapidly developed without fully considering the people who had to use them. Engineers and designers soon learned that they needed to take into account human and environmental factors if new products were to be employed safely and effectively.
Some years ago, ergonomics researchers compared relative positions of the controls on a lathe with the size of an average male worker. They discovered the lathe operator would have to stoop and move from side to side to operate the lathe controls; the “ideal” sized person to operate the lathe would be 4.5 feet tall, 2 feet across the shoulders and have an arm span of 8 feet!
Fortunately, great strides in equipment design have been made in recent years, much of it due to competitive marketing, and some due to government requirements. For example, Darrell Hinklin at Toro says workers compensation standards are so rigid in Scandinavian countries that riding mowers are frequently shipped without seats to those countries. Seats are added in-country, based on very rigid government standards. “A worker hurt on the job in Sweden, for example, is retired for life,” Hinklin says.
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