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Design for Diversity

June 1, 2007
Making lift truck hardware softer on the operator is a function of scientific study and human observation.

Manufacturers of lift trucks work diligently to design and engineer vehicles that will reduce material handling operating costs, as well as prevent equipment damage and injuries in the workplace. While any design configuration of the vehicle has to meet standards developed by the Occupational Safety and Health Administration (OSHA), other factors also influence design. Primary among them are ergonomics and diversity within the workforce.

"Ergonomics is the first thing we talk about when designing a new product," says Berry Mansfield, product manager, Cat Lift Trucks (Houston, "With industrial equipment, design teams have to keep an eye on key questions such as ‘Where does the product need to work?' and ‘What does it need to do?'"

While such application-related questions are important, they're asked after designers look at what they can do ensure the work compartment is comfortable and productive for the operator. "It's a challenge," says Mansfield, "because material handling equipment by nature has to be compact to work in confined spaces."

More than the increasing average age of workers, designers are responding to a more diverse workforce in the warehouse, says George Marshall, director of sales development warehouse products for Hyster (Greenville, N.C., "The challenge for the end user, our customers, is for them to be able to classify a job and have it appropriate for a diverse labor force."

Part of classifying jobs in a warehouse is whether the job is appropriate for male as well as female applicants. "As designers," says Marshall, "we have to build products that fit our customers' available workforce."

While designers talk about making products to fit a diverse workforce, it's really about making that workforce more productive. Operator fatigue becomes a major issue, particularly in the last few hours of the work shift. The challenge, therefore, is to make equipment comfortable over the entire shift. It's the little things that count most says Warren Bower, marketing director Class III products (pallet trucks and high-lift walkie vehicles) for Raymond Corp., Greene, N.Y.,

"Studies have shown," he says, "that peoples' shoe sizes are increasing so we've increased the size of the platform on our new pallet trucks." The increase in platform size was made because safe operation dictates that toes and heels not extend over the edge. By watching how the vehicles were used, engineers saw how operators shift around on the platform, trying to get comfortable and avoid fatigue.

Hyster's Marshall says because of the muscle power required to steer a walkie-rider truck, operating this equipment has most often been viewed as a male job. That's changing with today's diverse workforce. "We've added power assist steering to reduce down to seven pounds to nine pounds of effort what used to require 60 pounds to 80 pounds of muscle power on our B60Z and B80Z products," he says.

Power-assisted steering also makes the truck more productive by increasing the load capacity by lengthening the tines. "Because of load weights," explains Marshall, "we were restricted to tines 96 inches long, or shorter. Now, we can go to tines as long as 144 inches and improve productivity by 16% to 18%."

Help from the customer
Customer input can have a major influence on lift truck design. In the course of a work shift in a distribution center, a pallet truck, for example, can be used by numerous people for various tasks.

"When working on a new design, we work closely with our customers," says Raymond's Bower, "There's always a wish-list of things, some are cost-prohibitive and others are just not feasible. In the end, we have to determine what to put into the design that will yield the most efficient way to use the truck."

Marshall says watching how people use a lift truck has led to several changes in design at Hyster. "Because operators have to turn to look to the rear while driving, we made the movable seat. And when they do turn around, we noted a tendency to grab the upright of the overhead guard. So we installed a hand grip and a horn button on the upright."

Other ergonomic innovations have ranged from simple things like cup holders to more technically challenging systems such as laser guidance that tell the operator when the load is within proper range of high shelves and on-board cameras for positioning.

Mansfield of Cat says operator input has led to full-suspension seating that offers adjustments for weight and lumbar support, and seat belts that don't cinch since operators have to move and work in reverse throughout the day.

The purpose of such innovations are not limited to operator comfort. "We have a presence detection system," says Mansfield, "that disables the drive and hydraulic functions if the truck senses the operator is not seated." This system also provides warning alerts for seat belts and parking brakes.

Raymond's Bower notes that observations of truck users found that an operator of a walkie-rider gets on and off the vehicle a couple hundred thousand times per year. That observation led them to reduce the step height of vehicles to 9.5 inches, thus offering less impact on the body.

"We also look at things like where the operator leans against the truck to determine the natural points for grab bars," says Bower. "This brings together all the little things that will insure the operator is more productive."

What's down the road
Beyond workforce diversity how trucks are powered will have an influence on future vehicle designs.

"The biggest thing happening in electrical vehicles these days," says Hyster's Marshall, "is the mode of power. Electrical vehicles can produce an almost equivalent level of performance as the internal combustion engine. As a result, how batteries change in size and format will be critical over the next five years."

Having the same level of power in a smaller area, he says, challenges the designer because large batteries are part of the counterbalance of a truck. They also predicate the area available for the operator. So, if you design for a smaller battery, for example, what becomes of the operator? Therein lies the challenge says Marshall.

Making minor changes in design can take as few as a couple of months, while designing from the ground up takes years. Consequently, Cat's Mansfield predicts more evolution than revolution in truck design.

"Similar to the automotive industry," he says, "we foresee [current] ergonomic features becoming standard equipment. The concept is the same: increase the number of comfort and convenience features on the trucks so that the operator will enjoy operating the product."

One area where he sees innovation coming in the operator compartment is in assisting the visibility of the driver. "Mast designs are becoming more streamlined, visibility through the overhead guard is getting better and the front cowls of trucks are being lowered to improve low-level visibility."

Achieving safe operation is equal parts operator education and awareness. Features designed to do a job more safely and more productively are the goals of lift truck manufacturers. Manufacturers say, however, the function of good management is to recognize diversity in the workforce and select the right person and the equipment for the job, something that cannot be learned or designed.

The power assist steering on this B80Z Hyster pallet truck makes the opertor more productive since he can move more material with the extended forks.

The handle on this Raymond model 8400 pallet truck is designed to allow the operator to walk clear of the platform while selecting orders.

Complete floor mats and lower steps as illustrated by this CAT truck are important design contributions generated by concern for operator comfort.

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