casar handling

8/12/2019 Casar Handling

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Handling, Installationand Maintenance ofSteel Wire Ropes


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Handling, Installationand Maintenance of Steel Wire Ropes

by Dipl.-Ing. Roland Verreet

1. The handling of steel wire ropes .......................... Page 4

1.1 How steel wire ropes should be unloaded ............ Page 4

1.2 How steel wire ropes should be stored ................. Page 6

2. The installation of steel wire ropes ...................... Page 8

2.1 Unwinding a steel wire rope from the coil ............ Page 8

2.2 Unwinding the steel wire rope from the reel ......... Page 8

2.3 The installation procedure .................................. Page 10

2.4 Winding the steel wire rope from the reelonto the drum..................................................... Page 13

2.5 Installing the new rope with the help of theold one or by a thinner rope ................................ Page 13

2.6 Installing under load ........................................... Page 16

2.7 Breaking in the steel wire rope ........................ Page 17

2.8 Cutting steel wire ropes ...................................... Page 19

3. The maintenance of steel wire ropes .................... Page 21

3.1 Relubricating steel wire ropes ............................. Page 21

3.2 Cleaning steel wire ropes .................................... Page 233.3 Removing broken wires ....................................... Page 23

3.4 Cutting or shifting steel wire ropes ...................... Page 24

3.5 End- for- ending steel wire ropes ......................... Page 24

4. Concluding remarks ........................................... Page 26

5. Additional CASAR literature ................................ Page 27

6. What is .....? ....................................................... Page 28

7. What is a compacted strand? .............................. Page 29


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1.1. How steel wire ropesshould be unloaded

When handling a steel wire rope,the first trouble often occurs im-mediately upon receiving it: thefork of the fork lift truck is either placed under the reel or inside thecoil (Fig. 1).

In both cases it might damage thesurface of the rope. The damagemay not be discovered until much

later and it could happen that the

Fig. 1

manufacturer of the wire rope isheld responsible. If possible, therope, when received on coils or reels, should not have any con-tact with a metal hook or the fork of a forklift truck. Instead, it should be lifted by means of a widetextile webbing sling (Fig. 2). It isadvisable to lift a reel by means of a shaft which is put through itsaxis bore (Fig. 3 + 4). If the fork of the forklift truck is longer than the

width of the reel, the reel can also

be lifted at the flanges.


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Fig. 4

Fig. 2 Fig. 3


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1.2. How steel wire ropesshould be stored

Steel wire ropes should be storedin a clean, cool, dry place indoors.

The ropes must not be allowed torest on the floor. They can beplaced on pallets (Fig.5).

If outdoor storage cannot be avoi-ded the ropes must be covered ina way that moisture cannot cre-ate corrosion problems (Fig. 6).

Although plastic foil protects theropes from rain, condensationfrom beneath might not be ableto escape and could damage theropes permanently. To avoid con-densation problems, it is advis-able to use breathable water-proof fabric covers readily avail-able from tarpaulin manufac-

turers. When storing a number of spareropes, the following rule should

be applied: first in - first out. Thismeans, the ropes should be usedin the order of delivery. In this

way it can be avoided that cer-tain ropes are only put into serv-

ice after being stored for many years.

It is self-evident that the differ-ent ropes in stock must be clearly marked to avoid the possibility of confusion (e.g. if similar ropes of different tensile strength arestored.) In addition proper re-

cords have to be kept which makeit possible to trace the history

of any rope back to the manufac-turer on the basis of storingnumber, specification, date of or-der and date of delivery.


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Fig. 6

Fig. 5


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In the latter case ensure that thesurface is clean; sand or grit that sticks to the lubricant might dam-age the wires when the rope trav-els over sheaves.

2.2. Unwinding the steel wirerope from the reel

An unreeling stand (turntable)should be used to unwind a wirerope from its reel (Fig. 9).

Another accepted unreeling me-thod is to mount the reel on a shaft supported by two jacks (Fig.10).

2. The installationof steel wire ropes

When installing steel wire ropes,extra care must be taken that theropes are unwound from the ringor reel without torsions and with-out any outer damage. The sameapplies to reeving the ropes intothe system.

2.1. Unwinding a steel wirerope from the coil

If a rope is delivered on a coil, it iseither unwound on a turntable(Fig. 7) or the coil is rolled alongthe ground like a hoop (Fig. 8).

Fig. 7


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Fig. 8

Fig. 9


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wire rope; at the same time theproportions of lengths of the ropeelements and finally the distribu-tion of load within the rope arechanged. A rope that is unwound

at the sides of the coil or reel willtry to resist the enforced torsionsand form loops. When pulled taut these loops will result in irrepa-rable kinks (Fig. 14). Steel wireropes with kinks are not safe tooperate and must be discarded.

2.3. The installationprocedure

The most advantageous way of installing a steel wire rope variesfrom system to system. In any

Rolling the wire rope along thefloor (Fig. 11), as it is sometimesrecommended in the relevant lit-erature, does not work very wellin practice because the reel always

unwinds less wire than the dis-tance the reel travels, so that withthis method the rope has to bedragged along by the worker.

Under no circumstances must therope be pulled off a coil while it islying on the ground or looped over the head of the reel (Fig. 12 and13), because this procedure willinevitably induce one torsion per

wrap into the rope.

Every torsion will change the lay lengths of the strands and of the

Fig. 10


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Fig. 13

Fig.14


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when being drawn from the wirerope closer by means of a capstan.

When delivered to the customer the rope is bent in that direction.Make certain that it bends in the

same direction when it is woundfrom the reel onto the drum (Fig.15). If the rope is wound at the

bottom of the drum, it shouldleave the reel at the bottom and

vice versa: i.e., always reel fromtop to top or from bottom to bot-tom.

If this procedure is not strictly fol-lowed, the rope will either try totwist between reel and drum or it

will later try to regain its preferredposition when in practical service.In both cases structural changesof the rope may occur (Fig. 16).

2.5. Installing the new rope with the help of the oldone or by a thinner rope

If the new rope is pulled in by theold one or by a thinner rope onemust make sure that the connec-tion between these ropes is abso-lutely safe. In addition, it must beensured that the thinner rope can-not rotate. Rotation-resistant steel

wire ropes or three-strand fibreropes for instance, can be recom-mended for this purpose.

When using conventional wireropes one must at least make surethat they have the same directionof lay as the rope to be installed.

case a procedure should be cho-sen that (under justifiable ex-penditure) guarantees the least risk of torsions and avoids dam-age to the rope by contact with

parts of the construction.

With some machines it may beadvisable to discard the old ropefirst and to install the new oneafterwards. With other machines,particularly with bigger ones, it might be better to pull in the new rope attached to the old one. An-other possibility is to use a thin-ner rope by which the wire ropeproper is pulled into the system.

This method is often used withnew equipment.

In every single case careful con-sideration is necessary as to

whether the wire rope should bepulled through the whole reevingsystem or whether it should first

be wound from the coil or reel ontothe drum and afterwards bereeved into the system.

If one end of the rope has a fittingattached, there is no other possi-

bility than pulling the loose ropeend through the whole reevingsystem.

2.4. Winding the steel wirerope from the reel

onto the drum

During the manufacturing proc-ess every steel wire rope receivesits preferred bending direction


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Fig. 16

Fig. 15


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If the new rope is pulled in withthe help of the used one, the tworope ends are often buttweldedtogether. A connection of that kindcan transfer the twist of the old

rope, built up in the reeving sys-tem, into the new rope. By that method of installation the new rope may be extremely damaged.

There are even more reasons why that procedure is highly problem-atic:

It is true, that when using specialelectrodes the welded connectionpresents acceptable results in a pull test with a straight rope; but

because of the great length of therigid connection zone the very same connection could break due

to the enormous bending stresses when running over sheaves.

If that connection is applied, itssafety should be increased by us-

ing a Chinese finger. Fewer prob-lems are caused by connecting wire ropes with welded-on padeyes or chain links (Fig. 17), whichare joined by either strands or thin

wire ropes. This connection pro- vides satisfactory load capacity, it is flexible and prevents the trans-fer of twist from the old rope intothe new one. When using twostrands to pull the rope into place,these will indicate the intensity of twist in the old rope on the basisof the number of turns they havemade during the installation pro-cedure.

Fig. 17


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Another possibility is connecting therope ends with Chinese fingers. Theseare tubes made out of braided strands,

which are pulled over the rope ends andthen secured at their ends with tape

(Fig. 18). Under load the Chinese fin-gers will contract and hold the ropeends by friction.

When installing a lang lay rope onemust take care that the Chinese finger cannot unwind from the rope like thenut from a screw. It is helpful to wrap a tape around the whole rope length to

be held by the Chinese finger to increasethe friction.

2.6 Installingunder load

To achieve perfect multiple layer spool-ing of the rope on the drum it is very important - particularly with the so-called Lebus spooling-to apply a tensioning load to the wire ropes dur-ing the installation.

If the first layers are not under tension,they might be too loose, so that the toplayers might be wedged into the bot-tom layers under load. This could seri-ously damage the rope. The unwindingrope might even be clamped, so that thedirection of spooling could suddenly bereversed during the course of unwin-ding. The result could be the abrupt lift-ing of the load that was actually travel-ling downwards.

The tensioning load should range from1% to 2% of the minimum breaking loadof the wire ropes. In many cases it might Fig. 18


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generate the tensioning load by jamming the rope, for instance between two boards (Fig. 21).Structural changes would deformthe rope beyond repair.

2.7. Breaking inthe steel wire rope

After the rope has been installedand before it is going to do itsproper job, several run-throughsof the normal operational circleshould be carried out under light load (Fig. 22). The new ropeshould be broken in, so that thecomponent parts can settle andadjust themselves to the actualoperating conditions. It is most unfortunate that in practice only

suffice to wind the rope quite nor-mally in order to unwind it andthen rewind it with the help of anouter load. In other cases, how-ever, e.g. when erecting a tower

crane that has not yet reached itsmaximum height, the procedurementioned above is not possible.In these cases the tensioning loadmust already be applied when in-stalling the rope.

Ample rope tension can be provided by a simple plank bearingagainst the reel flanges (Fig. 19)or by a braking disk attached tothe reel (Fig. 20). The brakingcords (hemp ropes with a steelcore) will be provided by the ropemanufacturer. Under no circum-stances should one attempt to

Fig. 19


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Fig. 20

Fig. 21


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too often the exact opposite of thisrecommendation is performed:quite frequently after installingthe rope overload tests are carriedout with loads beyond the safe

working load of the system.

2.8 Cutting steel wire ropes

In many cases the user must cut steel wire ropes. Hand cutters aresufficient for rope diameters up to8 mm. Mechanical or hydrauliccutters will be required for larger sizes.

The best method is to use a highspeed disc cutter. Unless the ropeis being scrapped the use of flamecutting equipment is not recom-mended.

Careless cutting can result in the balance of tension in the rope be-ing destroyed. This is particularly important when cutting rotationresistant ropes where the strandsmay have been deliberately non-preformed as part of the manu-facturing specification.

In every case, each side of the cut must be properly seized to prevent strand disturbance. Insulatingtape cannot prevent strand move-ment and annealed (iron) wireshould always be used.

After marking the position of thecut the end of the seizing wire islaid along the rope axis leavingFig. 22


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3. The maintenanceof steel wire ropes

Steel wire ropes must be serviced

regularly, the kind of maintenancedepending on the lifting device, itsuse and the selected rope. Regu-lar maintenance may considerably increase the service life of a steel

wire rope.

3.1. Relubricatingsteel wire ropes

During production the rope re-ceives intensive lubrication. Thisin-process treatment will providethe rope with ample protectionagainst corrosion and is meant toreduce the friction between theelements which make up the ropeas well as the friction betweenrope and sheaves or drums. Thislubrication, however, only lasts for a limited time and should be re-applied periodically.

German Standard DIN 15 020specifies: Steel wire ropes must

be relubricated at regular intervals, depending on their use, par-ticularly along the zones subjectedto bending. If for operational rea-sons relubrication cannot be car-ried out, shorter service life of therope is to be expected and the in-spection intervals have to be ar-ranged accordingly. The influ-ence of lubrication and relubrica-tion on the service life of the ropeis illustrated in Fig. 24.

sufficient length to secure bothends by twisting when the seizingis complete.

The rope and this wire end are

now wrapped moving away fromthe location of the intended cut (Fig. 23a). The rope is tightly

wrapped for a distance of approx.three rope diameters (Fig. 23b).

Both ends of the seizing wire arethen pulled tight and twisted to-gether for a length of one rope di-ameter (Fig. 23c). The twisted con-nection is then hammered into a strand valley.

After preparing the other side of the intended cut accordingly therope can now be cut (Fig. 23d).

Instead of using one long seizingit is also possible to apply at least three seizings the size of one ropediameter each on both sides of theintended cut.


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When choosing the relubricant, it must be ensured that it is in ac-cordance with the recommenda-tions of the rope manufacturer.Further details can be obtained

from CASAR Drahtseilwerk Saar.

There are several techniques of lubricant application: The most common ones at present arepainting or swabbing (Fig. 25a).

Quite often the lubricant is ap-plied at a sheave (Fig. 25b), some-times a continuous drip methodis used. If only a little lubricant isrequired, pressure spray nozzlescan be applied.

Various other systems allow theapplication of a continuous bath

(Fig. 25c). Maximum penetrationof the lubricant into the gaps of the rope can only be guaranteedif high pressure lubrication is ap-plied with the help of a pressure

lubricator (Fig. 25d).

With this method the two halfs of a sleeve, which is equipped withrubber sealings, are clampedround the rope and screwed to-gether. While the rope runsthrough the lubricator the lubri-cant is pressed into the sleeve at a pressure up to about 30 bars.

It is important with all different methods of relubrication of steel

wire ropes that they are carriedout regularly right from the begin-ning of the service life of the rope

Fig. 24


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Effective cleaning without proper tools is quite a laborious job. For cleaning steel wire ropes the Ca-nadian Rigging Manual recom-mends an appliance with three

rotating wire brushes and an air blast drying system to follow. An American manufacturer offers a rope porcupine, a sleeve equip-ped with brushes, which is drawnalong the steel wire rope.

3.3. Removing broken wires

If during an inspection ends of

and not only after the first dam-age has been ascertained.

3.2. Cleaning

steel wire ropes

DIN 15 020 recommends: Fromtime to time very dirty steel wireropes should be cleaned exter-nally.

This applies particularly to ropesoperating in extremely abrasiveconditions and to those that takeup chemicals.

Fig. 25

a b

c

d


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Another typical local damage oc-curs on the drum at those sections

where the rope rubs against theadjacent winding (crossover point)and must be deflected to the side.

If the damage caused in these sec-tions is the main reason for dis-carding the rope, several cuttingsor shiftings will move the stressesto different rope zones and possi-

bly multiply the service life of therope.

3.5. End- for- endingsteel wire ropes

On some machines, various ropesections are subjected to very dif-ferent stresses. The drag rope of a dragline, for instance, is mainly subjected to bending fatigue at thedrum end, whereas the section at the bucket end is subjected to se-

vere abrasion by being draggedthrough the rubble.

Particularly in the USA and in theUK it is common practice to re-

verse the rope after a certain timeof service (end for ending) so that now the drum end of the rope,

which then usually is in better condition, can be subjected to the

wear at the bucket end.

The effect of such measures israther controversial. In any casethe expenditure will only pay off,if the value of the rope exceeds thecosts of the rope installation.

broken wires are detected whichmight cross adjacent wires anddestroy them when running over sheaves, these broken wire endsmust be removed.

Under no circumstances shouldthe broken wire ends be pinchedoff with a pair of nippers (Fig. 26).

The best method is to move the wire ends backwards and for- wards until they break deep in the valley between two outer strands(Fig. 27). With thicker wires a toolshould be moved backwards andforwards on the surface of therope, thus bending the wires un-til they break.

3.4. Cuttingor shifting steel wire ropes

Very often wire ropes must be dis-carded although only short ropesections, e.g. the one that climbsto the second layer on the drum,are seriously damaged, while therest of the rope is still in perfect condition.

In cases such as this the servicelife of wire ropes can be enor-mously increased by shortening,shifting them at the fixing point

by a span that removes the sec-tion of the rope which has hadmost abuse out of the criticalzone.

After this procedure an adjacent section will be subjected to theabuse.


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Fig. 26

Fig. 27


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4. Concluding remarks

For reasons of space this brochure

can only deal with general ques-tions of handling, installation andmaintenance of steel wire ropes.However, the publisher, CASAR Drahtseilwerk Saar GmbH, andthe author, Dipl.- Ing. Roland

Verreet, would always be pleasedto give their opinion on any spe-cial problems.

For further editions of this bro-chure the author will appreciatesuggestions for improvements or any comments, if these are ad-dressed to:

Ing.-Bro fr Frdertechnik Dipl.-Ing. Roland Verreet Grnenthaler Strae 40 a D-52072 Aachen

Tel 02 41 / 17 31 47Fax 02 41 / 1 29 82e-Mail: [email protected]

Cartoons: Rolf Bunse, PR GmbH Werbeagentur und Verlag, Aachen, Germany Setting, Layout and Production: PR GmbH Werbeagentur und Verlag,Grnenthaler Strae 40a, 52072 Aachen, Germany PR GmbH Werbeagentur und Verlag 1987/2004


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Additional Casar Literature

If you would like to receive additional Casar literature, please copy this form, fill inthe number of copies and your full address and send it to Casar via mail or fax it to

Fax No. ++ 49 6841 8091 359

Please send me free of charge the following brochures:

....... copies of the brochure Casar General Catalogue

....... copies of the brochure Steel wire ropes for cranes: Problems and solutions

....... copies of the brochure New wire rope designs for multi-layer drums

....... copies of the brochure Technical documentation

........copies of the brochure Which rope for my crane?

........copies of the brochure Handling, installation and maintenance

....... copies of the brochure Wire rope end connections

....... copies of the brochure Wire rope inspection

....... copies of the brochure Calculating the service life of running steel wire ropes

....... copies of the brochure A short history of steel wire ropes

....... copies of the brochure The rotation characteristics of steel wire ropes

....... copies of the brochure Analysis of the bending cycle distribution

....... copies of the CD Casar CD (Macintosh + Windows)

Address:


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WHAT IS ?

Wire

Strand

Rope

Left Hand Lay

Right Hand Lay

Ordinary Lay

Langs Lay

Conventional Strand

Compacted Strand


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compacted strandconventional strand

In order to produce a compacted strand, a conventional strand madeout of round wires is drawn through a compacting tool. During thisprocedure, the wires are plastically deformed, the strand diameter isreduced and the surface is made smooth. The contact conditions

between the individual wires and the strand-to-strand contactsimprove.

Ropes made out of compacted strands have a higher breaking load, a greater flexibility and better rope-to-sheave contact conditions thancomparable ropes made out of conventional strands. Because of thelarger outer wires and the smaller exposed area they are more resistant to abrasion and corrosion.

Some of the Casar Special Wire Ropesare made out of compacted strands.

WHAT IS A COMPACTED STRAND?


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CASAR DRAHTSEILWERK SAAR GMBHCasarstrasse 1 D-66459 Kirkel GermanyP.O. Box 187 D-66454 Kirkel GermanyPhone: ++ 49-6841 / 8091-0Phone Sales Dept.: ++ 49-6841 / 8091-350

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