Get a Grip: Tool Ergonomics

Today, it’s common for products—from kitchen appliances to office chairs—to be promoted as “ergonomically designed” or “ergonomically friendly.” Such designs also are attributed to many of the tools electricians use. However, marketing often neglects to tell what “ergonomic” means and its legitimate value to end-users.

An ergonomically designed tool is comfortable to grasp in work conditions, keeps the hand in a neutral position as the user applies force, reduces the amount of vibration from the tool’s use, and is easy and efficient to use, said Alan Hedge of Cornell University’s Atkinson Center for Sustainable Futures and retired director of the university’s Human Factors and Ergonomics Laboratory.

Hedge believes there have been significant improvements in power drill design to encourage the use of a straight wrist power grip, to have an appropriate tool diameter for a comfortable grasp, to ensure the trigger is easy to operate, and to shift the tool’s weight closer to its center of gravity, reducing stress on the hands. Other ergonomic advances include adding a light to the tool, so the user can better see the work area while the tool is being operated.

“For tools such as pliers or pincers or scissors, the use of elements such as return springs allows the tool to be used by squeezing and then simply releasing the tool, and this reduces the load on the musculoskeletal system,” Hedge said.

When choosing an ergonomic tool, it is important to consider how comfortable the tool is in the hand when applying force, how easy the tool is to use, and whether it can speed up work performance.

“If tool design isn’t comfortable and it doesn’t improve the ability to do the task, it isn’t very ergonomic,” Hedge said.

Matching the job

For Greenlee, Rockford, Ill., ergonomic tools are designed to match the user and their job, making them more efficient, more productive and less prone to injury.

“The marketplace is saturated with hand tools, and many of the tools are made to match an ‘average’ model, which doesn’t accurately meet customer needs,” said Jacob Thomas, Greenlee ergonomic specialist. “Our ErgoLab strives toward understanding where and how our customers use our tools. We use that information to design tools to perform in true job conditions. Greenlee focuses on the user’s needs and how we can improve the customer experience while completing the job.”

Testing in Greenlee's ErgoLab
Testing in Greenlee's ErgoLab

The ErgoLab has designed, tested and approved many of Greenlee’s key ergonomic features, such as extendable handles, grip design and tool balance. Attention to these features makers users more productive and helps reduce injuries.

A tool’s grip and alignment are basic elements affected by ergonomic design, Thomas said.

“With grip, you want a handle that is softer and does not cut into the hand as you grip it,” he said. “However, a handle should be firm and solid to transfer force from user to tool efficiently. Also, the surface should provide good friction to prevent slipping. Diameter of the grip is important, and there is an optimum grip size for most individuals.

“Alignment is simply how the grip is oriented to the tool head and has a significant impact on a tool’s ergonomics because it alters the user’s posture and movement while using it. The human body is designed to move in certain patterns efficiently. If the job and tool force a user to go outside those patterns, they will expend extra energy, generate fatigue and can place themselves at risk for injury,” Thomas said.

Comfort, safety and value

Taylor Brinson, hand tools product manager, Southwire Tools, Carrollton, Ga., said an ergonomically designed tool offers improved comfort, utility, safety and value to its user.

Brinson said hand tool examples include handle geometries that conform to the hand’s natural form as well as the use of materials that provide more cushion than traditional dipped-handle pliers.

“Any repetitive motion or application becomes laborious over time. Many times, the simplest improvement can make a huge difference in comfort,” he said. “Improving ergonomics, efficiency and safety is our goal in developing any tool.”

An example is a new cable cutter with a handle design that takes stress off the user’s hands by requiring less cutting force.

“As long as we can continue to add innovation that is accepted among tradesmen, there will always be ways to make [tools] more functionally ergonomic,” he said.

Southwire’s S1018SOL-US wire stripper uses a grip compound that provides more hand comfort and follows the hand’s natural contour.
Southwire’s S1018SOL-US wire stripper uses a grip compound that provides more hand comfort and follows the hand’s natural contour.

Powering up

With power hand tools, ergonomic risk factors include high levels of exposure to noise, vibration, force and the muscle effort required.

“Exposure to high thresholds of these categories can put workers at risk for eardrum damage, vibration-induced white fingers, trigger-finger tendonitis, and carpal tunnel syndrome, to name a few,” said Corey Dickert, vice president of product management, Milwaukee Tool, Brookfield, Wis. “Manufacturers who understand the seriousness of ergonomic science bring all of that work in-house and make their team of ergonomic professionals a crucial part of the tool development process.”

Milwaukee Tool’s ergonomic research considers all of these factors and has invested in electromyography (EMG) technology to record muscle effort during a tool’s use. This technology collects objective ergonomic data that can be used to positively influence tool design. Greenlee also uses the technology.

“We have established a dedicated team of experienced, industry leading professionals, including a certified ergonomist, and other experts to focus on tool ergonomics,” Dickert said. “With the ability to measure up to 108 unique muscle groups throughout the body, we use EMG technology to produce tools that reduce peak muscle efforts and fatigue, which helps workers age and retire with greater strength and health.”

Dickert said Milwaukee Tool balances advanced ergonomics and increased productivity in its tool products.

Milwaukee illustration showing the muscles used to operate power tools
Milwaukee illustration showing the muscles used to operate power tools

Everyday innovation

“Ergonomics, to Hilti, means that we listen to our customers to bring application-relevant innovation to the market that supports the tradespeople who use them day in and day out,” said John Schmidt, business unit manager for power tools and accessories, Hilti, Plano, Texas. “We incorporate their feedback throughout our product-development cycle to ensure that the tools we deliver to them outperform in terms of safety, comfort and productivity.”

Hilti uses custom triggers and grip sizes to provide the right balance and feel. Its active vibration-reduction feature also improves the user experience.

“Grips and controls that are ergonomically designed lead to better and more intuitive control, which ultimately relates to safety,” Schmidt said. “The better a tool feels in the user’s hand, the less fatigue the user will experience. Tools that are designed to be balanced and transfer less vibration lead to higher levels of worker productivity.”

The light but powerful Hilti TE 50 SDS-max combihammer is equipped with active vibration reduction and torque control to reduce the stress on the user.
The light but powerful Hilti TE 50 SDS-max combihammer is equipped with active vibration reduction and torque control to reduce the stress on the user.

Lighter is better

“Safety and productivity are important focus areas for professionals in today’s construction markets,” said Ward Smith, director of product marketing, Stanley Black & Decker Inc. “If a tool can deliver better performance in a smaller and lighter weight design, then the tool’s user is going to benefit by completing the work faster and performing it with less strain. Weight and balance and overall feel of the tool in the user’s hand are very important.”

With a significant amount of work conducted overhead, users benefit from optimal balance and lighter weight tools.

“For concrete hammer drills, we have designed a floating handle that reduces the vibration of the tool that the user feels while drilling for an anchor,” Smith said. “Reduced fatigue allows the end-user to be more effective throughout the day. Repetitive drilling with higher vibration tools can cause health [problems] such as white knuckle disease.”

Smith credits brushless motors with enabling the design of smaller, lighter-weight tools. These tools fit better within users’ hands, and the added control features are enabled by the electronics, which gives users more functions for different applications.

Smith also said lithium-ion battery chemistry has been critical in delivering more runtime and higher power in a lighter weight tool.

The smaller form and lighter weight of DeWalt’s 20V MAX cordless cable stripper helps the user complete work faster and with less strain.
The smaller form and lighter weight of DeWalt’s 20V MAX cordless cable stripper helps the user complete work faster and with less strain.

Bosch Power Tools

Charlie Chippetta, product manager, 12V cordless tools at Bosch Power Tools, Mount Prospect, Ill., said ergonomics is part of the company’s DNA.

“The products we develop rely heavily on user experience and input from the field,” Chippetta said. “Ergonomics is related to efficiency, especially as it concerns worker productivity. Ergonomic design is based on how the tool feels in the user’s hand. Ergonomics offers users ease of use, comfort and speed, application accuracy and precision and a design that benefits personal health.”

Compact size and weight also play into this equation.

“Professionals want a power tool that can be used in tight spaces and overhead,” Smith said. “They also want that tool to deliver the power to get the job done in that compact form. Ergonomics doesn’t end with these characteristics. It also includes features like vibration control, lights on the tool, ease of attachment use, and other features that are built into the functionality of a tool that provide a sense of health and safety to the user. All of these advancements bring a better experience to the user, including greater safety.”

This Bosch 12V 5-in-1 drill driver is compact and lightweight and offers the performance of a larger tool. It enables users to work in tight spaces with less strain.
This Bosch 12V 5-in-1 drill driver is compact and lightweight and offers the performance of a larger tool. It enables users to work in tight spaces with less strain.

 

About the Author

Jeff Griffin

Freelance Writer
Jeff Griffin, Oklahoma City, is a construction journalist specializing in the electrical, telecommunications and underground utility construction industries. Contact him at up-front@cox.net .

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