Archive for the ‘Technical Information’ Category

Unreeling the Rope

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When removing the rope from the shipping reel or coil, the reel or coil MUST rotate as the rope unwinds. Any attempt to unwind a rope from stationary reel or coil WILL result in a kinked rope that is ruined beyond repair.

The following illustrations demonstrate the right and wrong way of unreeling a rope.

Special care must be taken not to drag the rope over obstacles, over a deflection shaft, or around corners.

Avoid large fleet angles between the shipping reel and the first sheave. The rope may roll in the sheave causing the rope to unlay. This is particularly important for all DoPar, langs lay, and non-rotating rope constructions.

Avoid reeving the rope through small deflection sheaves and avoid changing the plane from vertical to horizontal direction.

If you have to unspool large and heavy wire rope, use a brake to keep a slight tension on the rope. NEVER let the rope go slack and form loops.

All of these precautions apply to Python® as well as to standard 6-strand, 19×7, 19×19, and 34×7 wire ropes.

If in doubt, contact your nearest Unirope® representative.

 

If You Have to Cut a Rope

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Usually, you do not need to re-cut a wire rope. However, you may encounter situations where it becomes necessary to shorten the rope.

Be aware that the following constructions are just lightly preformed and are ALWAYS heat sealed (induction tapering) at the end:

Python® Multi
Python® Super 8, Type R, C and V
Python® HS 9, Type R and V
Python® Ultra
Python® Hoist
Python® Compac 35
Python® Compac 18
19×7/19×19 (depending on diameter)
34×7

The heat seal, which is sometimes coated with a red plastic material, prevents the rope ends from unraveling. Most Python® constructions are NOT preformed. Cutting without proper care WILL result in permanent damage of the rope.

In cutting any wire rope special care MUST be taken in seizing the rope end.

Two methods are suggested:
1) Seizing the rope end with soft iron wire.
2) Seizing the rope end with hose clamps.

After cutting the rope (see below) it is good practice to braze PYTHON®, 19×7, and 34×7 rope ends to ensure that they don’t unravel. Leave the seizings on the rope for added holding strength. Be careful not to damage the seizing while brazing.

We found that blade cutting a rope gives the best results. Be sure to use a cutting blade suitable for the job (We use cutting blades made by ‘PFERD-HORSE’ type ELASTIC # 80 EHT 230-2 A 24 SG INOX.) Follow the safety precautions for free hand cutting.

Cutting a rope with a torch may result in both uneven ends and damage to the seizing causing the strands to open up.

Rope diameter up to 14 mm (9/16″) may be cut with a FELCO C16 hand cutter.

Foreword, Measuring the Rope Diameter

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Foreword

In order to fully achieve the service life potential of Python™ and standard wire rope for demanding crane jobs, these step by step instructions should be followed. They are intended to prevent rope damage caused by kinks, untwisting, and loose strands during handling and installation.

We realize that the ‘real world’ is not perfect. This applies also to wire rope installation. It is impossible to cover ALL imaginable installation situations, location difficulties, and crane set ups. You will also find that these instructions are not very different from the installation procedure of 6-strand or 19×7 ropes. Many experienced Riggers may find some of the following “old hat”. If you notice any omissions or have ideas that we can incorporate into this brochure we will be most appreciative.

Use and Care of Wire Rope

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Some Information every user should know about use and care of wire rope.
What follows is a brief outline of the basic information required to safely use wire rope.

  1. Wire rope WILL FAIL IF WORN OUT, OVERLOADED, MISUSED, DAMAGED, or IMPROPERLY MAINTAINED.
  2. In service, wire rope loses strength and work capability. Abuse and misuse increase the rate of loss.
  3. The MINIMUM BREAKING STRENGTH of wire rope applies ONLY to a NEW, UNUSED rope.
  4. The Minimum Breaking Strength should be considered the straight line pull with both rope ends fixed to prevent rotation, which will ACTUALLY BREAK a new, UNUSED, rope. The Minimum Breaking Strength of a rope should NEVER BE USED AS ITS WORKING LOAD.

  5. To determine the working load of a wire rope, the MINIMUM or NOMINAL Breaking Strength MUST BE REDUCED by a DESIGN FACTOR (formerly called a Safety Factor). The Design Factor will vary depending upon the type of machine and installation, and the work performed. YOU must determine the applicable Design Factor for your use.

    For example, a Design Factor of “5” means that the Minimum- or Nominal Breaking Strength of the wire rope must be DIVIDED BY FIVE to determine the maximum load that can be applied to the rope system.

    Design Factors have been established by ISO, OSHA, ANSI, ASME and similar government and industrial organizations.

    No wire rope should ever be installed or used without full knowledge and consideration of the Design Factor for the application.

  6. WIRE ROPE WEAR OUT. The strength of a wire rope slightly increases after the break in period, but will decrease over time. When approaching the finite fatigue life span the breaking strength will sharply decrease. Never evaluate the remaining fatigue life of a wire rope by testing a portion of a rope to destruction only. An indepth rope inspection must be part of such evaluations.
  7. NEVER overload a wire rope. This means NEVER use the rope where the load applied is greater than the working load determined by dividing the Minimum Breaking Strength of the rope by the appropriate Design Factor.
  8. NEVER ‘SHOCK LOAD’ a wire rope. A sudden application of force or load can cause both visible external damage (e.g. birdcaging) and internal damage. There is no practical way to estimate the force applied by shock loading a rope. The sudden release of a load can also damage a wire rope.
  9. Lubricant is applied to the wires and strands of a wire rope when manufactured. This lubricant is depleted when the rope is in service and should be replaced periodically.

  10. Regular, periodic INSPECTIONS of the wire rope, and keeping of PERMANENT RECORDS SIGNED BY A QUALIFIED PERSON, are required by OSHA and other regulatory bodies for almost every rope installation. The purpose of inspection is to determine whether or not a wire rope may continue to be safely used on that application. Inspection criteria, including number and location of broken wires, wear and elongation, have been established by ISO, OSHA, ANSI, ASME and other organizations.

    IF IN DOUBT, REPLACE THE ROPE.

    Some inspection criteria on rope, sheaves and drums are outlined further in the Technical Information section.

  11.  When a wire rope has been removed from service because it is no longer suitable, IT MUST NOT BE RE-USED ON ANOTHER APPLICATION.
  12. Every wire rope user should be aware of the fact that each type of fitting attached to a wire rope has a specific efficiency rating which can reduce the working load of a rope assembly or rope system, and this must be given due consideration in determining the capacity of a wire rope system.
  13.  Some conditions that can lead to problems in a wire rope system include:
    • Sheaves that are too small, worn or corrugated can cause damage to wire rope.
    • Broken wires mean a loss of strength.
    • Kinks permanently damage a wire rope.
    • Environmental factors such as corrosive conditions and heat can damage a wire rope.
    • Lack of lubrication can significantly shorten the useful service life of a wire rope.
    • Contact with electrical wire and the resulting arcing will damage a wire rope.

     

The above is the partially rewritten publication ‘WIRE ROPE AND SLING SAFETY BULLETIN’.
Some of its content was adapted to our specific requirement and does not truly reflect
the original as published by the WIRE ROPE TECHNICAL BOARD.