Greenlee Super Tugger 6000 Series Instruction Manual page 13

Cable Pulling Principles (cont'd)
Cable Pulling Forces (cont'd)
At the Pulling Rope
The product of a force (f) moving through a distance
(d) is energy (f x d), and may be measured in newton-
meters or foot-pounds. Energy is stored in a rope when
the rope is stretched. This is similar to the way energy is
stored in a rubber band when it is stretched. Failure of
the rope or any other component of the pulling system
can cause a sudden uncontrolled release of the energy
stored in the rope.
For example, a 100-meter nylon rope with a 50,000
newton average breaking strength could stretch 40
meters and store 1,000,000 joules of energy. This is
enough energy to throw a 900-kilogram object, such as
a small automobile, 113 meters into the air.
Greenlee Tools, Inc.
6000-Series Super Tugger
A similar double-braided composite rope could store
approximately 300,000 joules of energy. This could
throw the same object only 34 meters into the air.
The double-braided composite rope stores much less
energy and has much less potential for injury if it were to
break.
Double-braided composite rope is the only type of rope
recommended for use with the Super Tugger cable
puller. Select a double-braided composite rope with an
average rated breaking strength of at least 115.6 kN
(26,000 lb).
Stored Energy
Stored Energy
13
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Cable Pullers
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