Ergonomics: Finding and maintaining the golden zone
Manufacturing, warehousing and distribution have traditionally been associated with some amount of physical strain on employees. But heavy lifting, repetitive movements and the constant pressure to improve productivity often result in injuries and high turnover. In an effort to avoid those consequences, end-users and suppliers have worked to develop ergonomic solutions that better serve an aging and diverse workforce.
Lift trucks, initially intended to simply move materials through a facility, are borrowing from the creature comforts of modern cars to provide enhanced comfort and productivity. Workstations, once designed to cram as much as possible in the smallest space, are now optimized to reduce strain and can even be adjustable to the specific dimensions of an individual worker. In nearly every case, an emphasis on form has also improved the function of equipment and operators.
“Customers are giving more thought to ergonomics than they did even five years ago,” says Lance Reese, director of technical solutions for order fulfillment at Intelligrated. “In years past it was not much of a consideration at all. But in most projects we see now, there is a focus on ease of tasks, organization, effective communication and basic comforts.”
Reese predicts these sorts of workforce issues will continue to challenge the industry as technology, equipment and work areas are re-imagined in light of ergonomic optimization. Modern spoke to a few industry experts to get a sense of the customer concerns and goals that are giving ergonomics a comfortable seat at the table.
One size does not fit all
Since fatigue, retention and injury rates are far from predictable, it can be tricky to quantify the return on an investment intended to improve worker comfort. But the value of an ergonomic mentality is undeniable, according to Mike Shannahan, owner of Cynergy Ergonomics. “Some companies use a couple of young, strong people in a low-paid job, and the policy is to just burn through them in six months,” he says. “A company with that mentality won’t invest in ergonomic solutions, but seems to ignore the cost of training someone every six months. The companies with 30-year veterans always make the investment, and if you prevent one worker from blowing out his rotator cuff, you’ve paid for it all right there.”
But it’s not enough to ensure an aging employee is comfortable. Many other demographics—gender, height, weight, youth, special needs—should impact the design of equipment and processes. With the correct equipment, says Shannahan, a small woman can do the same work as two strong young men. There are also trends such as SKU proliferation and e-commerce that impact labor management in a different way. For instance, cross-training might be a good way to enable the dynamic reassignment of labor, but prevents a worker from customizing a workstation only to his or her preferred specifications.
Suppliers, on the other hand, are increasingly customizing workstation solutions to the application. Dehnco, a supplier of industrial workbenches, emphasizes the importance of a partnership in the creation of the optimal workstation. In these environments, the concept of the “golden zone” has been around for some time. Operating in this zone, items should be presented to workers in such a way that they rarely need to lift their arms above their shoulders or reach below their waists. But those heights are decidedly different for a 5-foot-3-inch worker and a 6-foot-3-inch one.
“All of that wasn’t taken into consideration in the past as heavily,” says Ross Halket, executive director of automation sales for Schaefer Systems International. “The golden zone puts fast movers in the middle and slow movers on bottom, but the slotting was mostly about moving product. Now it’s about keeping associates happy and productive longer.”
Moving the product, the person or both
Adjustable workstations can help position the golden zone, but according to Michael Renken, vice president of sales for Advance Lifts, it’s not always possible to bring the work to the person. Sometimes you have to position the person to the work. Work access platforms, marketed decades ago as carousel order picking lifts, have been repurposed to serve this need for precise worker positioning. “The adjustable platform can be reset between shifts or in an application where the lift is moving every 3 minutes, 6 inches at a time,” says Renken.
Such lifts might be customized with advanced sensors to enable precise movements around high-value works in progress, or they might be basic replacements for ladders and step stools, says Louis Coleman, director of sales and marketing for Autoquip. Coleman says no detail can be overlooked when considering the ergonomics of a platform. “Should a handrail be tilted or padded where a worker rests his elbow?” Coleman asks. “If he has to open the handrails repeatedly, how much effort does that take? Should there be an assist mechanism for that?”
Renken offered another example of a customer who needed to move large, bulky items from a parts room to a mezzanine. A new platform lift designed for the safe transport of both materials and humans enabled the worker to ride with the load, instead of sending it up, walking up stairs, meeting the load, and walking back down. “They now move product in half the time with half the effort,” Renken says.
In years past, the required effort was often neglected, says James Galante, director of business development for Southworth. In the case of lift-mounted turntables, it’s now ideal for the turntables to spin with friction less than 1% of the load, so a 4,000-pound pallet should require the worker to exert about 40 pounds of pressure. “It wasn’t until about five years ago that anybody even cared what the turning force was,” Galante says. “Now, turntables are much more popular. Twenty years ago, maybe 10% of our lifts were fitted with turntables. Now it’s three times that.” Whether lift- or floor-mounted, turntables can also cut the time spent walking around a pallet by as much as 30%, he says.
In a workstation with fixed heights, it’s important to take the size of individual items into account. “I often see conveyor heights designed for only the smallest or largest carton size,” says Schaefer’s Halket. “If the conveyor top is at 32 inches and you have a 6-inch carton, it’s now 38 inches to the top of the carton. If it’s a 20-inch carton, now you’re at 52 inches. The design should be a compromise somewhere in the middle.”
In a goods-to-person setup—where minimal walking already provides an ergonomic benefit—software could take this one step further. “If an associate always seems to be picking from the center and putting to the left,” says Halket, “you can design the system so that products are staggered from left to right, preventing the associate from wearing down one side of his body.”
By ensuring that all associates who use a station will enjoy the same levels of comfort, Halket says it’s possible to see productivity improve by as much as 15% to 20%.
Well-equipped for ergonomics
From lifts to overhead handling equipment to lift trucks, a transition from pneumatic to electric systems is a key trend in improving performance, safety and comfort. Even simple scissor lifts for palletizing and depalletizing can communicate with the conveyor, anticipating the dimensions of coming items or automatically indexing by layer. “An operator might simply press a button once to lower the lift by a fixed amount, instead of using a foot pedal to guess the ideal height,” says Coleman. “Integration with software and controls will only continue to grow.”
Intuitive controls are also migrating away from fixed stations to make workers more mobile. In addition to improving comfort, tablets and wearable systems can provide more information for order fillers or managers about the status of the work. Intelligrated’s Reese says these technologies will also help attract and retain a younger generation of employees who are more accustomed to multitasking. “They’re used to dealing with more input and output. It keeps them productive and keeps them intrigued day in and day out.”
New employees will also have little trouble acclimating to a new generation of lift trucks, which takes cues from automobiles for things as simple as the placement of turn signals, headlight switches and brake pedals.
“There’s been a pretty major change and advance in lift truck ergonomics over the last 10 years,” says Niels Ostergaard, sales, product, parts and customer support and solutions representative training manager for Toyota Material Handling USA. “I attribute it to businesses beginning to recognize that the operator compartment is their office. That’s where they conduct their business. Ergonomics is important both for productivity and a happier, more content associate. I’m convinced that it does reduce turnover.”
The goal is to keep an operator as comfortable and productive at the end of the shift as he or she was at the beginning, according to J.B. Mayes, manager of product management for counterbalanced products for Yale Materials Handling Corp. In a lift truck, this is no small task. Much like a cross-country flight, simply sitting in a forklift all day can be exhausting. And that’s assuming the operator is sitting the whole time. Some applications require the operator to mount and dismount the lift truck 40 or 50 times in a shift.
“It may seem minor, just entering the cabin, but in years past there was a huge step and you had to pull yourself up with your upper body,” Ostergaard says. “Now the steps and hand grips provide a much more natural movement.”
Once inside, the operator of a newer lift truck can expect a highly adjustable office space. Seats, available in eight or nine combinations of cushion type, seat covers, and swivel capabilities, might shift front to back by 6 inches. Mini-lever, fly-by-wire controls have often replaced direct linkages from the operator’s hand to the hydraulic valve, minimizing the effort required. In the near future, says Mayes, an access card might automatically load an operator’s preferred settings for the seat and steering column.
Mayes says ergonomics is all about a detailed understanding of the application. “If they’re reversing a lot, add the swivel seat and rear grip with horn,” he says. “If they are lifting above 30 feet, use a fork-mounted laser or camera to help them put and pull loads without craning their necks.”
Mayes also encourages plenty of operator input in the equipment selection process. “Some customers put a very high value on operator input, all the way to veto power,” he says. “They realize operators are not numbers, but people who help me do business.”
Whether evaluating lift trucks or any other equipment, Cynergy’s Shannahan stresses the importance of operator involvement from day one. “These people have great ideas. They are a fantastic asset and resource,” he says. “And the success rate is off the charts when they are involved.”
Companies mentioned in this article
Advance Lifts, advancelifts.com
Cynergy Ergonomics, cynergyergonomics.com
SSI Schaefer Systems International, ssi-schaefer.us
Toyota Material Handling USA, toyotaforklift.com
Yale Materials Handling Corp., yale.com