It is safe to assume we want to get the task (any task) done, do it well as well as stay safe and healthy in the process, right? After all, if our health is compromised, we may not be able to continue doing what we do to the best of our ability. But what does that have to do with hand tools or ergonomics?
Since hand tools have evolved over the years to be more complex and job specific, the user interaction faces challenges. These challenges include avoiding injuries, preventing uneven quality of work, decreased efficiency and productivity, which are all possible outcomes of improper hand tool selection and use.
It is important to understand that work-related musculoskeletal disorders (injuries of the muscles, tendons, joints and nerves) don’t present symptoms immediately. These types of injuries are caused by repetitive motion over time, and in order to stay clear of them it is important not only to use the right tool for the job, but also to use the tool correctly.
So how can these challenges be overcome?
When selecting a hand tool for a job there are basic guidelines to follow in the pursuit of an ergonomic hand tool. The goal of an ergonomic tool is to decrease grip strength or force necessary to use the specific tool, reduce the repetitive motion needed for using the tool. Eliminate or at the very minimum lessen any awkward body postures or wrist positions when using the tool and minimize the vibration transmitted to the hand and wrist.
Decrease grip strength
Providing an ergonomic handle makes an enormous difference in the amount of grip strength or force needed to operate the tool. Generally tools with longer or thicker handles require a lesser amount of force. The thicker handle provides more grasping surface, while the longer handle lets the operator generate more leverage by applying a smaller force at a greater distance.
Hand tools that open & close like pliers for example, require an optimal opening span for a range of users, including ones with smaller/larger hands, right/left handed and when wearing gloves. Opening span that is too wide will require the use of more force, which is counterproductive to ergonomic efforts.
Maintenance of hand tools is as important as proper selection. Power tools that are worn will need more force to use. To assure that grip strength and force to operate are reduced, a tool requires proper upkeep. Proper maintenance both assures a longer life span for the tool and it’s operator’s health.
Reduce repetitive motion
When performing a daily task that requires repetitive motion, one is at risk for Repetitive strain injuries (RSI). RSIs affect that muscles, tendons, nerves, and joints of the hand, arm, shoulder, neck and sometimes the back of the individual. RSIs have become more common with individuals who perform a repetitive motion on a continuous, daily basis.
RSIs can be caused by a combination of applied force, poor posture, and the repetitive nature of some tasks. The good news is that there are steps that can be taken to avoid repetitive motions over a long stretch of time.
Keeping hand tools properly maintained is one way to minimize the amount of force used. Switching to power tools, if possible, can also decrease repetitive motion. Switching hands, if possible and safe, is another way to reduce repetitive motion.
Eliminate awkward body postures or wrist
Selecting the proper tool may not be enough. There are tasks that require an awkward body or wrist positioning. This frequently depends on the operator’s height, hand size, weight, and amount of force they can apply, even gender.
However, it may be the task at hand rather than the operator, which requires a specific body position, for example – operating the tool while lying down/standing. While working in an awkward body position, it is important to have a tool with the appropriate handle type, size, and/or length. These small variations will affect the ability to apply grip strength and could help the operator to finish the task faster and with less force applied, and by that eliminate some of the effects of the awkward body position required for the task.
Vibration transmission to the hand and arm is usually associated with power tools. While power tools can decrease many of the causes for RSIs (shorter time of use, less force applied etc.), they have their own disadvantages. This chief one being vibration. Exposure to constant vibration over a long period of time is in itself a cause for RSIs.
Minimizing the amount of vibration transmitted to the hand and arm is affected by the tool’s design, weight and attachments. Also proper maintenance is key in keeping a tool’s vibration down.
When selecting a hand tool, think of the causes of work-related musculoskeletal disorders, the suggested modifications for the tool to make it ergonomic, and shop accordingly.