INSTALLATION, OPERATION AND MAINTENANCE RECOMMENDATIONS

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The primary factor in wire rope performance is selecting a wire rope with the best combination of properties for the job. The service life of that rope can be greatly extended by following a planned program of installation, operation, maintenance and inspection to avoid the most common causes of wire rope failure:

KINKING will result in permanent rope deformation and localized wear. It is generally caused by allowing a loop to form in a slack line and then pulling the loop down to a right permanentset.

OVERLOADING results in accelerated wear, abrasion, rope crushing and distortion on drums and sheaves, and could result in complete rope failure.

DRAGGING wire rope over a bank or some other object results in localized wear, which means shorter life.

IMPROPER SPOOLING results in crushed and distorted ropes and comes from careless installation and operation of the rope.

WHIPPING a line, which results in many squared off broken wires, comes from jerking or running the line loose.

The following recommendations are general guides for getting the longest life from your wire rope. All Rigging Company representatives are available to provide advice in specific situations. Our technology and experience are as close as your telephone.

Unloading, Unreeling and Uncoiling

Suitable precautions should be taken to prevent dropping of reels or coils during unloading and moving. If the reel should collapse, it may be impossible to remove the rope without serious damage.

Special care should be taken in unreeling wire rope to avoid kinking, which can result in permanent damage to the rope. The reel should be mounted on jacks or a turntable so that it will move freely. It should be unreeled straight and under enough tension to keep it from starting a loop.

A coil should be unwound by rolling along the floor like a hoop. Coils should never be laid flat and the free end pulled out.

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Winding on a Drum

Proper practices for transferring rope form reel to drum:

The reel should be placed as far from the drum aspossible in order avoid putting any turn into the rope. Rope should be wound from top-to-top or bottom-to-bot- tom to avoid reverse bends, which tend to make a rope harder to handle.

Use enough tension to avoid kinking.

There is usually only one way to install rope on a grooved drum.

On ungrooved drums, the “rule of thumb” guides installa- tion. The first represents the drum; the index finger the wire rope; and the thumb the direction of the proper dead end location. use the right hand for right lay ropes, left hand for left lay ropes. For overwinding, the palm is down; for underwinding, the palm is up. Most drum anchors are set for right lay rope since it is the most common specification.

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regular-lay-5-2 INSTALLATION, OPERATION AND MAINTENANCE RECOMMENDATIONS On installations where the rope passes over a sheave onto the drum, the maximum fleet angle (angle between the center line of the sheave and the rope) should be not more than 1 1/2 degrees for a smooth-faced drum and 2 degrees for a grooved drum. A 1 1/2 degree fleet angle is equivalent to 38 feet of lead for each foot of rope travel on either side of the center line of the sheave. Smaller fleet angles may result in the rope piling up on the durm. Larger fleet angles may cause excessive wear from rubbing against the flanges of the sheave as well as excessive crushing and abrasion of the rope on thedrum.

Break In

A few trips through the working cycle at slow speed and light load will set the strands firmly in place for smooth, efficient operation.

On applications using a wedge socket, such as drag and hoist ropes, it is also a good idea to cut off a short section of rope to allow twist to run out and to equalize the strands.

Operation

Skillfull operation is important to wire rope performance. Rapid acceleration, shock loading and excessive vibration can cause premature rope failure. Smooth, steady application of power by the equipment operator can add signifi- cantly to wire rope service life.

Shifting Wear Points

Some sections of most wire ropes get more wear than oth- ers. A regular inspection program will identify points of wear and lead to wear-shift practices that will extend wire rope life.

In many commom situations, cutting off short lengths of the rope will redistribute the points of maximum wear:

Rope on a drum with two or more layers will wear at the point where the rope starts each successive layer.

Crane ropes will fatigue at an equalizer sheave. Careful inspection is required to identify fatigue points.

Hoist ropes will frequently fail from vibration fatigue at sockets,clips and dead end points.

On most installations, wear and fatigue are more severe on one half of the rope than the other. Changing a rope end-for-end more evenly distributes wear and fatigue from repeated bending and vibration.

Lubrication

Factory lubrication is not always sufficient to last the useful life of wire rope. Periodic field lubrication may be required to minimize friction and provide corrosion protection.

Important guides for field lubrication.

Ropes should be inspected frequently to determine the need for lubrication.

Clean the rope thoroughly with a wire brush, scraper or compressed air to remove foreign material and old lubri-cant from the valleys between the strands and the spaces between the outer wires.

The lubricant should be applied at a point where the rope is being bent in order to promote penetration within the strands. It may be applied by pouring, dripping or brushing.

Used motor oil is not recommended as a wire rope lubri-cant.

Measuring Wire Rope

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The diameter if a wire rope is the diameter of the smallest circle which will enclose all the strands. Measurements should be made to the outer wires.

MATCHING THE WIRE ROPE WITH SHEAVES AND DRUMS

The ratio of the diameter of the wire rope to the diameter of operating sheaves and drums (D/d ratio) is particularly important to service life. A sheave or drum that is too small for the rope diameter will cause premature failure due to bendingstresses.

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Efficiency falls as the D/d ratio becomes smaller. This curve, based on static test data only, illustrates the decline of bending efficiency for 6 x 19 and 6 x 37 classifications ropes as the D/d ratio is reduced.

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Other values are permitted by various standards. For example ASME B 30.5 allows minimum hoist rope D/d ratio of 18 and boom hoist rope D/d ratio of 15.

To calculate the Recommended sheave diameter for a 6 x 19 classification wire rope of 3/4” diameter would be 51 x .75 = 38 1/4”) Rope speed also affects fatigue life. Higher

operating rates require largersheaves. Reverse bends from one sheave to another should be avoided. Other factors that affect bending fatigue life are load, number of cycles and condition of the sheaves and drums.

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Consult the wire rope manufacturer for recommendations.

Service life increases as the D/d ratio becomes larger.

This curve, based on bending and tensile stresses only, illustrates the relative performance increase.

MATCHING GROOVES TO THE WIRE ROPE

Grooves should be spaced so that one wrap of rope does not rub against the next wrap during operation. Grooves in sheaves and drums should be slightly larger than the wire rope to permit the rope to adjust itself to the groove. Tight grooves will cause excessive wear to outer wires; large grooves do not support the rope properly.

Wire ropes are manufactured slightly larger than nominal size. maximum allowable oversize tolerances are shown in the following table.

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As a rope is run through a groove, both become smaller. A used goove can be too small for a new rope; thus acceler-ating rope wear. A compromise between rope life and machining frequency must be made.

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Grooves should have an arc of contact with the wire rope between 135 and 150 degrees. They should be tapered to permit the rope to enter and leave the groove smoothly.

Field inspection groove guages are made to the nominal diameter of the rope plus 1/2 of the allowable rope oversize tolerance. When the field inspection guage fits perfectly, the groove is at the minimum permissiblecontour.

The lenth of rope that caan be wound on a drum or reel may be calculated as follows. L= lenth of rope in feet. All

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WIREROPE

Carefully conducted inspections are necessary to ascertain the condition of wire rope at various states of it’s useful life. The object of wire rope inspection is to allow for removal of the rope from service before the rope’s condition, as a result of usage, could post a hazard to continued normal operations.

The individual making the inspection should be familiar with the product and the operation as his judgment is a most critical factor. Various safety codes, regulations, and publications give inspection requirements for specific applications.

The following inspection procedure, taken from the ASME B-30 series, serves as a model of typical inspection requirements.

Frequent Inspection

All running ropes and slings in service should be visually inspected once each working day. A visual inspection consists of observation of all rope and end conections which can reasonably be expected to be in use during daily operations. These visual observations should be concerned with discovering gross damage such as listed below, which may be an immediatehazard:

Distortion of the rope such as kinking, crushing, unstranding, birdcaging, main strand displacement or core protrusion. General Corrosion. Broken or cut strands. Number, distribution and type of visible broken wires. Lubrication

Special care should be taken when inspecting portions subjected to rapid deterioration such as flange points, crossover points and repetitive pickup points on drums. Special care should also be taken when inspecting portions subjected to rapid deterioration such as flage points, crossover points and repetitive pickup points on drums.

Special care should also be taken when inspecting certain ropes such as: Rotation-resistant ropes such as 19×7 and 8×19, because of their higher susceptibility to damage and increased deterioration when working on equipment with limited design parameters.

Boom hoist ropes because of the difficulties of inspection and important nature of these ropes.

When damage is discovered, the rope should either be removed from service or given an inspection as detailed in the section below.

Periodic inspection

The inspection frequency should be determined by a particular installation or similar installations, severity of environment , percentage of capacity lifts, frequency rates of operation, and exposure to shock loads.

Periodic inspections with a signed report should be performed by an appointed or authorized person. This inspection should cover the entire lenth of rope. The indi-
vidual wire in the strands of the rope should be visible to this person during the inspection. Any deterioriation resulting in appreciable loss of original strength, such as described below, should be noted and determination made as to whether further use of the rope would constitute a hazard:

Distortion of the rope such as kinking, birdcaging, crushing, unstranding, main strand displacement, or core protrusion.

Reduction of rope diameter below normal diameter due to loss of core support, internal or external corrosion, wear of outside wires. Severely corroded or broken wires at end connetions. Severely corroded, cracked, bent, worn, or improperly applied end connections. Lubrication.

Special care should be taken when inspecting portions subjected to rapid deterioration such as the following:

Portions in contact with saddles, equalizer sheaves, or other sheaves where rope travel is limited.

Portions of the rope at or near terminal ends where corroded or broken wires may protrude.

Rope Replacement

No precise rules can be given for determination of the exact time for replacement of rope, since many variable factors are involved. Continued use in this respect depends largely upon good judgment by an appointed or

authorized person in evaluating remaining strength in a used rope, after allowance for deterioration disclosed by inspection. Continued rope operation depends upon this remaining strength.

Conditions such as the following should be sufficient reason for questioning continued use of the rope or increasing the frequency of inspection.

In running ropes, six randomly distributed broken wires in one lay, or three broken wires in one strand in one lay. (The number of wire breaks beyond which concern should be shown varies with rope usage and construction. For general application 6 and 3 are satisfactory. Ropes used on overhead and gantry cranes (as defined in ASME B-30, 2-1983) can be inspected to 12 and 4. Rotationresistant ropes should be inspected to 4 and 2.)

Wire rope removal criteria are based on the use of steel sheaves. If synthetic sheaves are used, consult the sheave or equipment manufacturer.

One outer wire broken at the contact point with the core of the rope which has worked its way out of the rope struc- ture and protrudes or loops out from the rope structure.

Wear of one-third the original diameter of outside individual wires. Kinking, crushing, birdcaging, or any other damage resulting in dstortion of the rope structure. Evidence of any heat damage from any cause. Valley breaks.

Reductions from nominal rope diameter of more than:

In standing ropes, more than two broken wires in one

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lay in section beyond end connections or more than one broken wire at an end connection.

Replacement rope shall have a strength rating at least as great as the original rope furnished by the equipement manufacturer or as originally specified. Any deviation from the original size, grade, or construction shall be specified by the equipment manufacturer, original design engineer, or a qualifiedperson.

Ropes not in regular use

All rope which has been idle for a period of a month or

more due to shutdown or storage of equipment on which it is installed should be given inspections as previously described before being placed in service. This inspection should be for all types of deterioration and should be performed by an appointed or authorized person.

Inspection records

Frequent inspection no records required. Periodic inspection: In order to establish data as a basis for judging the proper time for replacement a signed report of rope condition at each periodic inspection should be kept on file. This report should include points of deteriora- tion previouslydescribed.

A long range inspection program should be established and include records of examination of ropes removed from service so a relationship can be established between visu- al observation and actual condition of the internal structure.

Galvanized Structural Wire Strand

Carefully conducted inspections performed and recorded on a regular basis are necessary to ascertain the condition of structural strand at various stages of its useful life. The object of inspection is to allow for removal of the strand from service before its condition, as a result of usage, could pose a hazard to continued normaloperations.

The individual making the inspection should be familiar with the operation, as his judgment is a most critical factor. Special care should be taken at end terminations or at dampener devices, as these are generally the most critical areas.

Conditions such as corrosion, number, type and distribution of broken wires, and diameter reduction should be evaluated and compared with previous inspection results. The actual condition of the strand and inspection history together can then be used to decide if continued use of the product is advisable.

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Note: Special methods and techniques may be used by wire rope engineers or qualified persons to determine the possible existence of internal corrosion or broken wires in structural strand or similar conditions which may exist out of sight in termi- nal connections.

Example: Wire breaks may sometimes occur just inside the nose of the socket making visual inspection difficult. Judgments on wire integrity can be made by tap- ping or “sounding” the wire by a person exprienced in this inspection technique. If you have doubt about the method to use for inspectiom or the condition of the strand or fitting, contact your nearest All Rigging Company location.

For further information on wire rope inspection refer to the American Iron & Steel Institute’s Wire Rope Users Manual.