Tiếng ViệtPYTHON® HIGH PERFORMANCE WIRE ROPE
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 6×19 or 6×36 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 diedrawn 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 inconvenience 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 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 9×17 spin resistant, 19×7, 19×19, and 24×7 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 6×19 COMPAC® ropes, others prefer the simplicity of standard 6×19 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 19×7/19×19 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 ‘8×19 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 19×7 or 19×19 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 19×7 nor 19×19 types fulfill the demand on strength and/or on non-rotating properties.
For the older Pecco “double sheave lower suitcase block”, which is used strictly in a 2-line configuration, a regular 6×36 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 19×7/19×19 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 !
