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Preventing Work-Related Musculoskeletal Disorders |
Visit
their web site at http://chppm-www.apgea.army.mil/ergowg2/index.htm
This publication was produced by the
Department of Defense (DoD) Ergonomics Working Group, in coordination with the
U.S. Army Center for Health Promotion and Preventive Medicine (USACHPPM). For
questions on ergonomics issues, please visit your local occupational health or
safety office or contact the appropriate service office listed on page 2 of
this guide.
Please submit comments specific to
this guide to the DoD Ergonomics Working Group Chair, c/o USACHPPM, ATTN:
MCHB-TS-OER,
Hand Tools and WMSDs
Hand tools, in one form or another,
are used in all occupations, and are designed to extend the range, strength,
mobility, and effectiveness of a person's upper limbs. However, poorly designed
tools or risk factors, such as awkward positions, mechanical compression,
vibration, and forceful exertions, can lead to injuries, accidents, and WMSDs.
The duration of exposure to these risk factors may also affect the worker by
increasing local and generalized fatigue and tissue stress.
Shortcomings in hand tool design are generally
easy to identify, and can often be resolved by applying some basic principles
outlined below.
§ Use special purpose tools.
§ Use lightweight, well-balanced, or counter-balanced tools.
§ Use a tool balance, holder, or jig
if prolonged use or holding is required.
§ Use powered hand tools whenever
possible.
§ Use the best grip for the task
(e.g., a "power grip" when high force is required).
§ Use only tools that have the
appropriate handle thickness, shape, and length for the job. In addition, the
tool handle should--
o Distribute
the hand-force concentration over a greater surface area.
o Be
comfortable to hold and well rounded.
o Reduce
compressive forces on the hand surface.
§ Be long enough to
distribute forces over the large, fleshy areas at the base of the thumb and
little finger.
§ Select tools that minimize stress on muscles and
tendons. You should be able to keep the wrist in a neutral or relaxed position
during tool use.
§ Allow for adequate finger clearance
if trigger use is required, or increase the size of the trigger so more than one
finger can be used.
§ Allow for the hose connection of
pneumatic tools to have a two-directional swivel.
§ Cover power tool handles with
vibration dampening material, such as SorbothaneŽ.4