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Overhead Cranes
Due to the vast variety of overhead cranes in service there is no 'standard'
rope construction which would fit all types. In most cases, cranes made
in North America require imperial size ropes either, Class 6x19 or 6x36
are the traditional choices.
To enhance the crane performance the use of Python® High Performance
rope is recommended. Python® wire rope can replace traditional 6-strand
construction without any changes to the crane, other than making sure
the sheaves and drum are in good condition.
If you upgrade from a standard strength 6-strand or 6-strand die-drawn
type select Python® Super
8R, in either left- or right hand lay. This type matches the breaking
strength requirement but will greatly outperform any traditional rope.
It requires corresponding drum grooving and thus ensures the most stable
rope block you can imagine.
If you experienced some block twisting you want to select Python®
MULTI. Even slight block twisting is a constant inconvinience when
you have to position a C-clamp into stacked coils, for example.
Another application is where both rope ends are attached to the drum.
The result is that 1/2 of the rope always spools into a incorrect drum
grooving direction. Particularly 8-strand ropes without a plastic coated
core (as provided by most OEM's) tend to torque resulting in loose
strands and waviness. Using Python®
MULTI reduces, and in most cases eliminates eliminates, such problems.
Because of it's very unique construction Python-MULTI does NOT require
corresponding drum grooving and still has shown the highest degree of
service life increase of all Python types.
Some North American made overhead cranes have been converted, or can be
converted, to higher lifting capacities using high strength Python®
SUPER 8V, Python® HS-9V
or Python® Ultra compacted
constructions. We suggest not to attempt to convert your crane without
professional advice, nor to select such without consultation with your
local Python Distributor.
Overhead Cranes and Rotation Resistant Ropes
As a rule, Non-Rotating or Rotation Resistant rope types shall only be
used if the lower sheave block tends to spin and Python® Multi did
not cure the problem. Generally, non-rotating ropes will have a LOWER
fatigue life than standard constructions, although they seem to have 'finer'
wires and appear to be more flexible. Specifically 9x17 spin resistant,
19x7, 19x19, and 24x7 rotation resistant ropes tend to break up from
the inside and require frequent and careful inspections. Most of these
rope types on overhead cranes are smaller sizes between 5/16" and 7/16"
(between 5 mm and 11 mm).
For larger diameter non-rotating ropes (> 1/2" or 13 mm) we recommend
Python® Lift or Python®-Hoist
with a plastic coated core to prevent premature internal wire breaks.
Under no circumstances do we recommend Python®
Compac 18 for such applications.
Scrap and Grab Cranes, Piledrivers
These are, in essence, "wire rope destruction machines". Some users had
good results with 6x19 COMPAC® ropes, others prefer the simplicity
of standard 6x19 ropes. For shock loading applications some users have
had very god results with Python®
Super 8V yet there were reports also of good performance with plastic
(impregnated-delete) filled rope types (BXL), PFV or Cushion ropes are
some trade names). In essence, we believe that the human factor, crane
design, crane location, and scope of work creates such a mix of conflicting
requirements that we, as the rope supplier, can only suggest that whatever
works best for YOU in YOUR specific situation is also the best rope for
you. This may not be the case for the chap next door.
Hoisting Rope for Mobile Cranes
Most of the smaller capacity US made cranes like Grove, Terex, P&H, Century,
National, operate best with Python®
Compac 18. It's compacted outer rope surface is superior on multiple
layer drums where traditional ropes tend to fail due to friction damages
at the winding crossover points. However, Python®
Compac 18, when used to it's full fatigue life, tends to break up
from the inside out (as all 19x7/19x19 rope do). Therefore, in high cycle
applications and for some high load ratings (e.g. on Manitowoc's) Python®-LIFT
ropes are either already installed by the crane manufacturer, or are the
recommended upgrade choice. As an alternate rope selection we recommend
Python® Compac 35 as this
rope combines high strength, low rotation and die-drawn strands at a very
attractive price.
Under NO circumstances do we recommend the so called '8x19 spin resistant'
rope construction. In service this type of rope WILL to break up from
the inside out and when used with one end free to rotate looses up to
40% of its breaking strength. Catastrophic and unexpected rope failures
are the result.
Hoist Rope on Tower Cranes
For tower cranes we do not recommend the use of 19x7 or 19x19 style rope
types; this includes out Python®
Compac18 . Rotation Resistant ropes (having less than 14 outer strands)
are very difficult to inspect since they tend to fatigue from the inside
of the rope. Also, nearly all European tower cranes require high strength
non-rotating ropes and neither 19x7 nor 19x19 types fulfill the demand
on strength and/or on non-rotating properties.
For the older Pecco "double sheave lower suitcase block", which is used
stricktly in a 2-line configuration, a regular 6x36 IWRC rope is sufficient,
provided the building height is no more than 10-12 floors. Here, large
line spacing prevents the block from spinning.
For all other cranes we recommend Python®
Compac 35. For extremely high strength requirements Python®
Lift ropes are the choice.
Linden, some Kroll- and Comedil tower cranes which have the 3- or 4 sheave
arrangement in the block are 'rope killers'. The reverse bend in such
systems is so severe that short rope life MUST be expected. Under NO circumstances
should you use 19x7/19x19 ropes. Even if you use our Python® non-rotating
ropes we will NOT guarantee no bird-cages and other rope deformations
as a result of such reeving systems. There have been reported sudden and
unexpected rope failures. Such set ups are quick and easy to convert from
a 2 part to a 4-part line but it's not ideal from a wire rope standpoint
... and there is nothing we can do about it; you simply have to learn
to live with it and INSPECT ... INSPECT ... INSPECT !
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