English - Komatsu Forest

An ergonomically designed cab with a correctly adjusted seat reduces
the effects of vibrations.
tions low, and stable support for
the driver’s seat also helps reduce
vibrations. A seat with unstable
support can reinforce full body
vibrations.
ABOUT VIBRATIONS
Vibrations are usually divided
into two main types, full body
vibrations (shakes and jars) and
local vibrations, though here
we’ll focus on the full body type,
the main type of forest machine
vibration. Full body vibrations
occur when the structure on
which we sit or stand moves or
swings back and forward like a
pendulum, and this motion can
be described using physical measures.
The first measure is ampli-
INFO
24 JUST FOREST NO 4 • 2007
tude, the size of the vibration.
Amplitude is expressed in millimeters,
though in a forest
machine the amplitude can be up
to one meter (almost 40 inches).
The other measure is frequency,
which describes how often the
vibration occurs in a unit of time.
Frequency is expressed in Hz,
or vibrations per second. Other
characteristics contributing to
the effect are the total time the
vibrations continue, the direction
of the vibrations, and the type of
vibration. Vibration types are
divided into different groups. On
the one hand we have predictable
vibrations, and on the other
we have random vibrations,
which are most common in forest
machines. r
The effects of full body vibrations
Reducing vibrations
Drive sensibly
• Match your driving speed to the terrain.
• Drive carefully on sloping terrain as your driving
body posture can be adversely affected. Driving
on flat ground has less impact on body position.
• Drive smoothly and evenly. This also reduces fuel
consumption and machine wear.
• Work with smooth and fluid boom/crane movements.
Personal health and work environment
• Vary your working posture to avoid straining
joints and muscles.
• Adjust the seat and controls to match your height
and weight.
• Keep in good shape. This enables you to better
reduce the effects on your body.
• Take regular breaks.
Help from the machine
• Lower RPMs mean less vibration.
• Replace the seat if it’s old. A worn driver’s seat
and weak support actually reinforce vibrations
and make it difficult to correctly adjust the seat.
• Larger machines generally shake the body less
than small machines.
When someone is subjected to full body vibrations, muscles contract. This affects everything from heart rate to
blood pressure and balance. It’s impossible to predict who will be more seriously affected by vibrations. Everyone
reacts differently to them.