Solution Summary: Ergonomic Hand Tools
Ergonomic hand tools are an engineering control designed to minimize awkward and forceful hand exertions, and still maximize performance and work quality. Such hand tools may include, for example, non-slip and soft handles, lightweight handle materials, operating mechanism that reduce the force required, or handles and grips sized to minimize forceful gripping or awkward wrist postures.
Ergonomic hand tools are designed to minimize awkward and forceful hand exertion. The American Industrial Hygiene Association recommends that hand tool selection maximize performance and work quality, while minimizing physical demands placed on the worker.
Desirable hand tool features that make the tool more ergonomic:
- non-slip, soft material
- a sleeve can be used to cover hard handles, but be cautious because a sleeve adds to diameter and/or grip span of the tool (see below for diameter/grip span recommendations)
- make sure the sleeve fits snugly so that the tool doesn't slip out of the sleeve while someone is working.
- Lightweight material, such as titanium
- In an impact tool, like a hammer, select a material that will transfer less recoil shock, such as titanium
- Select spring-loaded handles that automatically return t an open position for pinching, gripping or cutting tools.
- Clamps, grips, or locking pliers can be used for tasks that require continuous application of force
Handle diameter for single-handed tools, such as a screwdriver
- Between 1.25 and 2 inches for power tasks (high force)
- Between 0.25 and .5 inches for precision tasks (low force)
- Grip span for double-handled tools, such as pliers
- For power tasks (high force)
- Closed grip span at least 2.0
- Open grip span less than 3.5
- Spring loaded handles are preferred
For precision tasks (low force)
- Closed grip span at least 1.0
Open grip span less than 3.0
spring-loaded handles are preferred
- Handle length - longer than the worker's hand width
Handle shape –
- Avoid finger grooves and sharp edges
Select a handle that helps to keep the wrist straight
- For horizontal forearm motions a bend handle works well
- For vertical movements a straight handle is usually the best choice.
Example of a straight vs. bent handled tools:
Figure 1. Standard set of pliers.
Figure 2. Ergonomic set of pliers
The California Division of Occupational Safety and Health website and NIOSH's Simple Solutions report both have some useful guidelines for hand tool selection that include many pictorial examples.
Stressful hand and wrist activity can cause musculoskeletal disorders (MSDs) such as muscle strains; tendonitis, which is inflammation of elbow and wrist tendons; or carpal tunnel syndrome, which is compression of a wrist nerve, resulting in finger numbness and loss of hand strength. The ergonomic hand tools can help reduce stressful hand and wrist activity by providing workers with a shape that is more natural and less stressful to grip.
How Risks are Reduced:
Ergonomic hand tools can reduce the risk of injury by:
- Reducing the amount of grip force required to operate a tool and perform a particular task
- Making it possible to perform a task while maintaining neutral, comfortable postures of the wrist, elbow, or other joints
- Reducing contact stress from tools that may 'dig' into hands by eliminating sharp edges, finger grooves, or excessively short handles.
Independent studies have shown an association between musculoskeletal disorders and risk factors such as forceful exertions, awkward postures, and contact stresses (e.g contact pressures are concentrated in a small area). Measures of forceful exertions, awkward postures, or contact stresses for ergonomics hand tools tend to be lower compared to the same measures for the equivalent standard versions of the same tool, according to some studies.
Companies such as Bahco North America, Klein TOOLS, Marshalltown Company, Snap-on Inc., StanleyTM, Stiletto, and Swanstrom Tools USA claim that their ergonomic hand tools are able minimize exposure to forceful exertions, awkward postures, and contact stresses compared to standard versions of the tools.
There have not been independent published studies measuring the effect of using ergonomic hand tools on the incidence of musculoskeletal disorders. Regardless, health and safety experts are convinced that workers will be less likely to develop musculoskeletal disorders if they use ergonomic hand tools due to reduced exposure to known risk factors.
Effects on Productivity:
Using the appropriate tool with ergonomic features can improve productivity because workers may be able to complete tasks more quickly and with less mistakes. This increased productivity may be due to reduced muscle fatigue, fewer mistakes, the ability to use more powerful gripping positions, and less lost time due to worker musculoskeletal illnesses.
Although it is generally a good idea to have soft handles because it reduces grip force requirements and prevents slipping, in some situations a soft handle may increase risk. In particular, if small shards of glass or metal are present in the work environment then it is possible for those shards to become lodged in the soft handle material and cut workers.
Make sure that if you add a soft sleeve to a handle that the handle diameter is still no more than 2 inches. Also make sure that the sleeve does not slip on the handle.
Dan Anton, PT, PhD, ATC; Zack Sinner, SPT; Neil Morris, SPT – Eastern Washington University
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Stanley Black & Decker
To obtain information, visit Stanley Black & Decker or contact 800-262-2161
Stiletto Titanium Tools
To obtain information, visit stiletto.com or contact 800-987-1849