Equip workers for better ergonomics.
The following examples illustrate how five companies examined the ergonomics of certain jobs. Each company found a way-by selecting a specific type of materials handling equipment-to redesign a job and eliminate risks to employee health and safety.
Some companies found that off-the-shelf hardware solved problems. Others developed their own custom equipment. Or slightly modified an existing device. In the instances reported here, the solutions were found in manipulators, pallet positioners, lift tables, and tilters.
But one can make a much longer list of materials handling equipment categories that improve ergonomics. Indeed, one can start by listing rather basic equipment and proceed on through to automatic palletizers and robotics. (This magazine's pages on new products and problem-solving ideas include other examples on a regular basis.)
You should also recognize that even "simple" equipment such as a hand truck, for example, can provide an ergonomic edge-one supplier now offers a hand truck with a patented mechanism that shifts the load's center of gravity to make lifting easier and safer.
Commitment to better work conditions is important. At Ford Motor and General Motors, engineering management is now more aware of ergonomics. The automakers' major labor union, the United Auto Workers, has negotiated agreements with each company which call for improved ergonomics. UAW's booklet, Sprains and Strains: A Worker's Guide to Job Design signals the union's push for change.
Will you engineer for better ergonomics? And will you bring workers into the loop of job redesign? New products and new systems offer chances to rethink job design. And just because a job "has always been done this way" doesn't make it correct, ergonomically.
Injuries and increased costs for worker compensation insurance may force your own greater involvement in ergonomics, moreover. And federal or state workplace safety inspectors may be at the plant gate someday soon with their "advice."
So, will you lead or follow? Here's what some leaders are doing to help you answer that question.
Teamwork drives ergonomic gains at Ford
As Ford Motor declares in its ads and commercials, Quality is job 1." Less well known, perhaps, is how Ford strives to make "Employee Involvment," or EI, far more than just a buzz phrase. Ford aims to make EI part of quality in automaking and quality in jobs.
EI can lead to improved ergonomics when the corporate culture encourages creative thinking on work design-from both a top-down and bottom-up perspective. That's what happened at Ford's St. Louis assembly plant when an employee team worked on finding a better way to install the rear seat in Aerostar vans.
The van's 3-passenger rear seat can weigh up to 100 lb, explains Tim Dwyer, manufacturing engineer. When installers tried to move a seat in manually through the vehicle's sliding door, it took two workers outside of the van to pass the seat to a third worker on the inside.
"It was an undesirable job from an ergonomic standpoint," says Dwyer. The worker inside had to use "some Kentucky windage" to get the seat installed right. And the workers outside the van had trouble getting enough leverage on the seat.
A Ford employee involvement (EI) team, however, developed a solution: a custom-made, articulating, mechanical arm moving on a ball-bearing slide and lifting the seat into the van. The arm takes the seat off a conveyor, after the seat belts are used to latch or couple the seat to the arm.
"The workers came up with the brainstorm of using the seat belts" for this purpose, Dwyer says. The method also serves as a "double check on the hold of the seat belts. And there's no lifting or straining."
Manipulators move heavy parts, provide layout flexibility
Diesel engine parts are heavy-too heavy to lift manually, in many cases. Floor-mounted, pneumatically-controlled manipulators provide an ergonomically sound and safe solution to the problems of moving these parts. The manipulators also are a cost-effective and flexible materials handling approach along the assembly lines at Cummins Engine in Jamestown, N.Y.
Traditionally, overhead bridge cranes combined with hoists were used to transport engine parts. "But the cranes were cumbersome," recalls Bob Reed, industrial engineer. Cummins also wanted more flexibility than overhead cranes could provide, moreover, so that changes in work flow on the factory floor could be accomodated readily.
Several back injuries-presumably related to workers trying to lift manually a 155 lb engine flywheel and position the part on the assembly-also helped spur the search for an alternative materials handling method at the Jamestown facility.
Cummins personnel first saw pneumatic manipulators in operation at another manufacturer's plant. After borrowing one of the devices and trying this industrial manipulator out in 1985, Cummins next proceeded to examine manipulators which were available from various manufacturers.
One company's manipulator (Coleman Equipment/Balaman) provides "unusually high flexibility in its controls," Reed says. The product's patented control circuitry automatically senses any weight within the machine's range of capacity and then balances the load without the need for adjustment on the part of the operator.
With this sensing capability, the operator can direct and keep his attention on putting the manipulator through its paces without adjusting for different load weights.
This capability is important when there's a range of part weights, such as 40 lb to 170 lb, to be handled as occurs at several of the devices. There's also a safety interlock on the manipulators' circuits so that premature drop of a load cannot occur.
All of the manipulators in use at Cummins from this equipment manufacturer are floor mounted. This feature results in "ultimate flexibility," says Reed.
Several workers can reposition a manipulator in an hour or so, if need be for a work flow change on the factory floor. Repositioning an overhead crane might take days to weeks to accomplish, he explains.
Cummins has "an absolute commitment to ergonomically designing the manipulators to operators' needs," Reed also declares. Manipulators have been purchased with simple hooks, for example. Then Cummins, with input from its operators, has designed its own end-of-arm tooling.
Pallet positioners help pack newspapers
Bring work to the worker. When a worker must stand to perform required tasks, set the work surface at a comfortable height. Avoid awkward postures when lifting. Work with, not against gravity, when possible.
These suggestions are among a number of factors to consider to improve the ergonomic conditions of a job. At the Boston Globe, a daily newspaper, the task of placing advertising inserts into the newspaper has been made less stressful, physically, for operators by following guidelines such as these.
Also helping the Globe meet these guidelines and ease the operators' task are pallet positioners. The pallet positioners are part of an on-line insertion system.
Each positioner can hold a pallet loaded with up to 2200 lb. of inserts. A positioner is placed near one of the inserting machines; as the operator unloads and feeds inserts into the machine, the pallet load rises, keeping the load at a proper height for feeding more inserts, explains the Globe's Barry O'Shaughnessy.
Before examining the use of these positioners, the Globe faced a materials handling challenge common to many newspapers. No doubt, your paper carrier recognizes one aspect of the challenge.
Today's Sunday newspaper is far from the light lob onto the front porch or doorstep it was years ago. Crammed with advertising supplements and other inserts, a paper can weigh up to 2 lb. That weight, multiplied by a six-figure circulation number, can stretch some muscles during the papers' process of distribution, along with the minds of readers the paper intends to stretch and inform.
Stuffing all those inserts into individual papers, moreover, could be a very labor-intensive, manual process. And one that might lead to lower back injuries or strains, and workers compensation claims.
Instead, the inserting process, as practiced at the Globe now, can prevent most injuries from ever occurring. And some of these procedures apply to countless industrial jobs where a palletized unit load is broken down manually into its individual parts, or depalletized.
The Globe uses pallet positioners (Bishamon) for depalletizing. Each positioner has a rotating top, which spins through 360' and gives the operator ready access to the entire pallet load.
The positioner is air actuated from a captive air system. The air system readily adjusts to load capacity.
After some four months of testing the pallet positioners in actual insertion operations, the Globe is finding the equipment well worth the investment, O'Shaughnessy says. There "definitely are productivity gains along with the improved ergonomics," he adds.
Lift table eases roll handling
Reneer Film Corp., Auburn, Penn., strongly believes that its workforce is its most valuable resource. The manufacturer of a variety of film products has sought out opportunities where applying sound ergonomics will enhance worker safety and productivity. And eliminating manual lifting has a high priority in this search.
Lifting rolls of film-which can weigh from 50 to 200 lbs. each-provides one example of how Reneer Film solved a potentially dangerous problem. At one time, the rolls, after they were produced in a calendar machine, were lowered manually to the floor.
Recognizing the risk of injury of this manual method, Reneer Film installed a lift table (Southworth) to do the lifting. By touching a button to position the lift table, the skilled calendar machine operators now perform the lifting step without the risk of injury.
Tilters avoid back strains among GM workers
Expose engineers to the principles of ergonomics. And what might you get? In the case of one operation at one General Motors assembly plant, increased ergonomics awareness led to installing equipment that helps workers avoid the risk of back injuries. In this instance the equipment solution was air-powered tilters for baskets of parts.
"We were developing procedures for a new GM van," recalls Paul Ehms, senior industrial engineer at the Tarrytown, N.Y., plant. "We had begun an ergonomics awareness program, and I had attended classes in ergonomics. That's really how it started.
"We said we're building a new product. And so we asked ourselves,
What can we do better?"' When this line of questioning was directed at a work procedure-previously a manual picking step-the answer became obvious: Find a way so that workers can avoid bending and stretching movements that might result in lower back injuries.
Previously, Ehms explains, workers would pick shock absorbers, solenoids, and other parts from a standard-sized wire basket. The basket was simply placed on the factory floor. And the basket's dimensions are such-54 in. by 44 in. by 40 in.-that when parts near the bottom are picked, the worker must stoop to reach them.
GM tested various tilters, Ehms says, for their suitability to facilitate the picking operation. One tilter (Autoquip), uses a shock absorbing mechanism to prevent overextension. This tilter also has other desired features, Ehms says, such as: it elevates the wire basket; it tilts the basket toward the operator; and it makes picking easier, particularly when reaching to get items from the bottom of the basket.
Because GM's Tarrytown plant uses many air-powered tools and thus has many air drops, the tilters were easy to install. Slots appropriately spaced on the tilter also make it easy for a fork lift truck to pick up and put down the equipment.
GM's safety director at Tarrytown has expressed appreciation for the decision to install the tilters, Ehms says. "The true test of the equipment, comes from the operators. They love the tilters."
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|Title Annotation:||equipment designed for safer work conditions|
|Publication:||Modern Materials Handling|
|Date:||Aug 1, 1991|
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