Owner's Manual for Thern 5PA5 and 5PA10 Ensign Series Portable Davit Cranes
page 7
A115771-0617
2.1
General Theory of Operation
2.1.1
THE INTENDED USE of this machinery is to lift and lower loads of its
rated capacity or less. It is not for lifting people or things over people.
2.1.2
THE FORCE REQUIRED to lift the load must not exceed the load rating of
the crane. Consider the total force required to lift the load, not the weight of
the load.
2.1.3
THIS EQUIPMENT CAN develop forces that will exceed the load rating.
It is the responsibility of the equipment user to limit the size of the load.
Inspect the equipment regularly for damage according to the instructions
contained in this manual.
2.1.4
PERFORMANCE RATINGS of the equipment are affected by the position
of the boom (hook reach).
Crane load ratings decrease as you extend the
reach.
See the Performance Characteristics Tables on pages 22-23.
a
LOAD RATING represents the maximum force that can be placed on new
equipment.
b
LIFT varies with the position of the boom and sheave and length of the wire
rope.
c
REACH varies with the position of the boom and sheave.
2.1.5
DUTY RATINGS refer to the type of use the equipment is subject to.
Consider the following when determining duty rating.
a
ENVIRONMENT: harsh environments include hot, cold, dirty, wet,
corrosive, or explosive surroundings.
Protect the equipment from harsh
environments when possible.
b
MAINTENANCE: poor maintenance, meaning poor cleaning, lubrication,
or inspection, leads to poor operation and possible damage of the equipment.
Minimize poor maintenance by carefully following the instructions
contained in this manual.
c
LOADING: severe loading includes shock loading and lifting loads that
exceed the load rating of the equipment.
Avoid shock loads, and do not
exceed the load rating of the equipment.
d
FREQUENCY OF OPERATION: frequent or lengthy operations increase wear
and shorten the life span of gears, bearings, sheaves, and other components.
Increase maintenance of the equipment if used in frequent operations.
2.1.6
AIRBORNE NOISE EMISSIONS vary depending on load and the type of
winch being used. Standard configurations do not typically exceed a sound
pressure level of 80dB(A) at workstations.
2.1.7
VIBRATION LEVELS vary depending on load and type of winch being used.
Standard configurations do not typically exceed vibration levels of 2.5 m/s
2
.
CONTACT THE FACTORY FOR ANY ADDITIONAL INFORMATION.
Figure 6 – Raising the
Boom
Important!
• Limit non-uniform winding by
keeping tension on the wire rope.
• It is your responsibility to detect
and account for different factors
affecting the condition and
performance of the equipment.
