Ergonomics - Atlas Copco

The advantages and disadvantages of each
basic handle type depend on the actual
machine, the work it is designed to do, and
the workstation at which it will be used.
When a machine is installed at a work-
station, the choice of handle depends on the
various combinations of work surface heights
and the amount of force which needs to be
applied for the tasks to be performed.
Working postures are an important
guide in the selection of tool handle. Special
consideration should be given to the hands,
shoulder, and upper arms. The hand and
forearm should always be aligned when
force is being applied.
If the shape of a tool causes extreme hand
postures, the operator will often compensate
by raising an arm, or elevating a shoulder.
The torque exerted on the shoulder is
governed by the angle of elevation of the
upper arm. Therefore this angle should
generally be limited to less than 20 degrees
when a tool is in continuous operation, in
order to reduce stress on the shoulder muscles.
Problem Deformation of joints Bursitis Inflammation in joint capsules Arthritis
Cause Repeated external loads over Inflammation Repeated load may dry out the Repeated use of
a long period of time. of a fluid filled synovial fluid that lubricates the arms in extreme
sac (bursa) joints. postures, shocks
serving as a cushion and repeated arm
to protect the rotations.
tendons from the
bony ridge.
Symptom Decreased joint mobility, Pain from the Pain during movement. Worn-out joints,
aches and pains. inflamed bursa. decreased mobility,
increased stiffness and
pain during activities.
Ergonomics Tools with high push forces Reducing the Designing tools and workstations Decreasing forces,
should be designed in a way forces and move- that allow variation in postures Improving work,
that enables the hands to ments and and less external loads. reducing or eliminating
be held in neutral posture. avoiding uncom- shocks and vibrations.
fortable hand and
arm postures.
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