Machines to lift and position
Devices that offer an ergonomic edge over manual handling foster safety, raise productivity, and may even turn workers into bionic operators.
By Tom Feare Editor At Large -- Modern Materials Handling, 6/1/2003
Should you be improving ergonomics in your workplace? The answer is hardly a simple one.
Regulating ergonomics in U.S. workplaces was a hot, front-burner topic in Washington up until two years ago. One likely outcome then was that new standards and a federal push on industry would spur usage of work methods and equipment to make tasks more comfortable, less physically stressful for workers.
It didn't happen. The Bush Administration has had other regulatory priorities. Its position on ergonomics takes a slower, more focused approach. Also, a sluggish economy since 2001 has cooled further the interests of some execs in improving job conditions-purely to gain better worker comfort and safety- in their factories and warehouses.
'Safety is now in the 'nice-to-have category,' ' says Brian McNamara, president, Southworth International Group (207-878-0700). In other words, equipment that lifts and positions pallets, for example, now has to provide more benefits than just a safety or ergonomics edge for users before it's purchased.
But that's not necessarily the case in industries where labor cutbacks in a soft economy have been made under a last-hired, first-fired policy, points out Scott Doane, president, Vacutrade USA (877-822-8873). Layoffs often leave behind a more senior workforce, he explains, with individuals who are less able physically to do manual tasks than laid-off, younger employees.
Others see the role of ergonomics in equipment choices diminished temporarily. 'Productivity gains are the real driving force behind purchases today,' says Bob Clark, vice president, Bishamon (800-358-8833). 'Ergonomics is a secondary factor.'
A number of employers, to their credit, are proactive about ergonomics. Ford, GM, and other automakers equate good ergonomics with good economics, says Steve Klostermeyer, global product manager, intelligent assist devices, Stanley Assembly Technologies (440-461-5500). They also are the major forces pressing a few companies to develop more 'smart' ergonomic equipment, for example.
Other employers are reactive - moving only after a worker is injured on the job. And perhaps acting only when insurers for workmen's compensation policies press for safer conditions, suggests Vacutrade's Doane.
Reactive employers pay a high price for waiting to act, however. 'A single workplace back injury can cost up to $35,000,' points out Peter Hong, president, Positech (800-831-6026). Yet there are many ways to avoid the costs of injury or illness on the job, as he says.
Some ways might involve simple, inexpensive changes in the workplace, observes Bishamon's Clark. Or they might require adding equipment. It's important, however, stresses Hong, 'to put the least amount of equipment possible between the operator and his/her task' in a specific job. That kind of application of equipment 'is the most successful and the least intrusive,' he adds.
Hong chairs the Ergonomic Assist Systems and Equipment (EASE) Council, a unit of the Material Handling Industry of America. Members of this EASE Council supply industrial manipulators, lift tables, intelligent assist devices, positioners for pallets and containers, vacuum lift devices, workstation cranes, air balancers, and related products.
Expenditures on this equipment buy a company greater safety, and better ergonomics through application of the proper equipment in the right circumstances. Higher productivity is another bonus.
'The vast majority of our end users get a ten percent increase in pure productivity,' says Southworth's McNamara, while others achieve 'time and productivity gains of up to 30% to 40%,' he adds. One Vacutrade installation with ten vacuum lifters has gone two years without a reportable workplace injury, says Doane, while productivity is up 25%.
Ending awkward movesManual handling tasks - and especially repetitive ones - are the root cause of many workplace ergonomic problems. A worker lifts, stretches, bends, reaches, stoops, twists, or otherwise moves awkwardly while handling loads or exerting force manually. Ultimately, a musculoskeletal injury can occur.
'Manual loading and unloading of pallets continues to be one of the most common and most injury prone tasks in industry today,' says Southworth's Jim Galante, director, product and market development.
Galante chairs another MHIA unit, the Lift Manufacturers Product Section. Its members make lift tables, dock lifts, scissor lifts, tilt tables, and manually propelled load stackers, which also offer ergonomic solutions through equipment to handling problems.
Equipment represented by manufacturers that are members of MHIA's EASE Council and its Lift Manufacturers Product Section offer low-cost solutions in many cases.
Costs for load handling and positioning equipment such as scissor lifts are in the range of $1,000 to as high as $5,500 per unit, for example, with container tilters at the high end.
Manipulator costs, meanwhile, range from $8,000 to $25,000 to handle a 200 to 500 pound load, says Positech's Hong. 'Historically, the heavier the payload, the more manipulation functions - like pitching, rolling over, or rotating - are requested. That drives up the price of the manipulator and tool solution.'
Vacuum lifter costs for a 70-pound capacity unit start at about $5,000. But that's without a supporting crane system and without customized tooling, says Vacutrade's Doane.
Scissor lifts, tilters, and other non-computerized, conventional lift assist equipment have a long history of usage. Some device types date back to the 1950s, others to the late 1970s. Modern versions are little changed save for added features and simple design changes. But these conventional equipment types have been proven in tens of thousands of factory and warehouse applications over the years.
Moving toward the bionic workerFully automated systems take the human factor totally out of the handling equation, of course. But automation generally does so at a very high cost. And it often lacks the flexibility to adapt to new conditions and processes, and to changed load weights and sizes.
'Smart' ergonomic technology known as 'intelligent assist devices,' or IADs, now occupies the middle ground between conventional lift assist/position devices and industrial robots, says Stanley's Klostermeyer.
'IADs add power steering to conventional materials handling equipment. They particularly do so for motion in the x-axis and the y-axis,' he explains. In effect, an operator power steers a heavy load through complex process steps with ease. The operator works with the IAD in a natural and intuitive manner, says Klostermeyer.
'The concept behind IADS is to create a human power extension, almost like a bionic arm,' observes David Butwid, vice president, Gorbel(800-821-0086). IADs 'are computer-controlled devices with sensors and servo power units that amplify the intent of the operator,' adds Jeff McNeill, Gorbel's marketing manager. 'Sensors make adjustments 100 times per second. It all happens so fast that the operator doesn't realize it's happening.'
IADs can 'do very well in the slow, precise steps of a process,' suggests Butwid, 'then move fast in other parts of a work cycle.' Speeds can range from 1 to 275 feet per minute.
Aside from their added microprocessor intelligence and servo motors, IADs resemble the more conventional crane, trolley, hoist, and related lifting devices of overhead handling systems in many cases, and manipulators in other instances.
Less costly than a full robotic installation, IADs are more expensive than conventional ergonomic assist equipment. Stanley's Klostermeyer says an IAD with a single axis of motion ranges in cost from $10,000 to $12,000, and roughly twice that amount for two axes of motion. Butwid says one of Gorbel's IADs - one with a z-axis lifting motion - costs around $5,400. Plus there's the added expense for the crane from which it is suspended.
When comparing IADs to more conventional lifting and positioning equipment, the end user needs to recognize 'the increased benefit of adding intelligence and servo control to conventional lift assist tasks,' suggests Klostermeyer.
Learn more about ergonomicsFor a good overview on how to identify, analyze, and implement ergonomic solutions to manual materials handling, consider purchasing the EASE Council's Ergonomic Toolbox. In a CD format with multimedia features, it can be ordered ($75 per copy plus $5 for shipping) through the web site, www.mhia.org. The Web sites of firms quoted here and other MHIA members also offer insights into products and their applications as well.
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