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A Comfortable Fit

A Comfortable Fit

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    John Deere's 844 J wheel loaders feature ceiling-to-floor windows for high visibility, lots of legroom for comfort, and joystick steering that eliminates the need for the operator to continuously keep an arm extended while operating the steering wheel.

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    Case Construction Equipment's E Series wheel loaders feature ceiling-to-floor windows so there are no obstructed views.

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    Positiec USA Inc.'s WORX Revolver line offers drills, saws, grinders, and other power tools with a handle design that decreases fatigue by offering multiple positions so workers can use the best angle and pressure without unnecessary strain or discomfort.

What operators want

Many equipment manufacturers agree that operators' concerns center around safety, comfort, and a machine's productivity and reliability.

“In the big picture, the operators' concern is whether they can get comfortable in the machine so they don't feel worn out or beat up at the end of a shift,” says Dave O'Keeffe, product marketing manager for John Deere's four-wheel-drive loaders.

Manufacturers and others research operators' needs through customer surveys, interviews, and focus groups. Case Construction builds prototypes, takes them to jobsites, and collects feedback from operators as they test the machines. Caterpillar uses ergonomic measurement techniques such as Kansei engineering to gauge operators' emotional response to cab designs and features. Kansei engineering translates subjective requirements into product design features, incorporating consumer emotion into the product design process.

The company also uses NASA TLX and SWAT mental workload scales to measure the amount of mental workload an operator is required to employ in a given cab or machine application.

These methods helped identify specific ergonomic needs:

  • Adjustable seats and controls for any size operator
  • Cabs with legroom
  • Climate control inside the cab
  • Sound insulation
  • Vibration/shock isolation
  • Visibility of the tool and around the machine from the cab
  • Low-effort controls
  • Intuitive displays
  • Safe and easy cab access (ladders, platforms)
  • Good communication with ground personnel.
  • Most machines today have been redesigned to include most or all of these features. For instance, Caterpillar has adjusted the design of its loaders and other machines to offer fully adjustable, padded seats and armrests, increased visibility, and decreased noise levels in cabs, joystick and/or fingertip types of control, and improved HVAC systems.

    One of the biggest ergonomic changes in John Deere's wheel loaders is joystick steering. “Joystick steering offers the operator the opportunity to steer the machine with one hand on an armrest while making slight movements,” explains O'Keeffe. “The joystick eliminates the need for the operator to continuously keep an arm extended while operating the steering wheel. It also eliminates the repeated rotation of the steering wheel, specifically in truck-loading applications.”

    For easy access in and out of the cab, Case's newest wheel loaders have angled steps that work more like stairs than a ladder. The loaders also have ride control, which allows the wheel loader arms and the lift cylinders to act as shock absorbers, so the load absorbs the shock before it is transferred to the operator. Ride control is one of Case's best features, says Wolf.

    And which features do owners and operators like best? With ergonomic designs becoming the standard, just shop around to find the best fit.

    For more on the companies in this story and their products, visit www.case.com,www.cat.com, and www.deere.com.

    — The author is the managing editor of Hanley Wood's PUBLIC WORKS magazine.


    From the Inside Out

    Heavy equipment such as wheel loaders are not the only machines designed with ergonomics in mind. As David Crawford, product manager for Tulsa, Okla.-based Hilti points out, users who are comfortable with the power tools in their hands are also more productive.

    Comfort and safety concerns can be seen in today's power tools, such as soft grips that rotate for a comfortable fit, automatic shut-off features that prevent injuries, and lighter weight tools for high productivity and easy handling. But to recognize other ergonomic features, one must look inside the tools.

    For example, Hilti's TE 76P and TE 76P-ATC Combihammers feature a low-pressure hammering system that minimizes vibration and shock. Instead of steel hitting steel, the steel pistons hit pockets of air that push other drill bits into motion. Another example is Hilti's TE 706-AVR Breaker. This breaker features a symmetrical design, which gives the tool good balance and reduced dynamic vibration, resulting in superior handling on the jobsite. Hilti's AVR Active Vibration Reduction system cuts vibration by one-half.

    “We're always trying to understand the application the tool will be used for and what type of contractor will use the tool,” says Crawford. This has resulted in creating well-balanced tools with minimal vibration that feel good in a user's hand.

    Another ergonomically-driven company is Positec USA Inc. of Charlotte, N.C. In 2005, it launched the WORX brand, featuring power tools that “fit the person.” This brand includes the Revolver power tool line with Ergo Sum design technology.

    Designed to conform to the body and fit the hand, these power tools incorporate angles, geometries, sizes, and shapes that provide the most efficient and comfortable interface between the hands and the body. A rotating handle system offers 65 degrees of rotation so users can select positions that require minimal reach, strain, or fatigue.

    Visit www.hilti.com and www.positecindustrial.com.