Handling & Installation
Receiving, Inspection and Storage
For all wire rope, the best time to begin taking appropriate care and handling measures is immediately upon receiving it. On arrival, the rope should be carefully checked to make certain that the delivered product matches the description on tags, requisition forms, packing slips, purchase orders and invoice.
After these necessary preliminary checks, the next concern is that of providing weatherproof storage space. If a wire rope is to be kept unused for a considerable amount of time, it must be protected from the elements. The ideal storage area is a dry, well-ventilated building or shed. Avoid closed, unheated, tightly sealed buildings or enclosures because condensation will form when warm, moist outside (ambient) air envelop the colder rope. Although a lubricant protects wire rope, this is not totally effective since condensation can still occur within the small interstices between strands and wires thereby causing corrosion problems.
On the other hand, if the delivery site conditions preclude storage in an inside space and the rope must be kept outdoors; it should be effectively covered with a waterproof material. Moreover, weeds and tall grass, in the assigned storage area, should be cut away; the reel itself should be placed on an elevated platform that will keep it from direct contact with the ground. Providing an adequate covering for the reel also prevents the original lubricant from drying out and thereby losing its protection.
Never store wire rope in areas subject to elevated temperatures. Dust and grit, or chemically laden atmospheres, are also to be avoided. Although lubricant applied at the factory offers some degree of protection, every normal precautionary measure should be taken with every coil or reel of wire rope.
Whenever wire rope remains in position on an idle machine, crane, hoist, etc., it should be coated with an appropriate protective lubricant. In these circumstances, as with ropes stored outside, moisture, in the form of condensation, rain or snow, may form on the wire rope. Some of the moisture may easily become trapped inside the rope and cause corrosion problems.
If the wire rope is to be kept inactive for an extended period while wound on the drum of the idle equipment, it may be necessary to apply a coating of lubricant to each layer as the rope is wound on the drum. Cleaning, inspection and re-lubrication should precede start-up of the equipment.
Wire rope Installation Checking the Diameter
It is most important to check the diameter of the delivered rope before installation. This is to make certain that the wire rope diameter meets the specified requirements for the given machine or equipment. With an undersized diameter rope, stresses will be higher than designed for and the probability of breaking the rope will be increased; an oversize diameter rope will wear out prematurely. This happens because of abuse to the rope caused by pinching in the grooves of the sheave and drum.
In checking, however, the actual rope diameter must be measured. And this is defined as the diameter of the circumscribing circle, i.e., its largest cross-sectional dimension. To ensure accuracy this measurement should be made with a wire rope caliper using the correct method. For measuring ropes with an odd number of outer strands, special techniques must be employed.
Improperly attached wire rope terminals lead to serious unsafe conditions. To perform properly, all wire rope elements must be held securely by the terminal. If this is not accomplished the strands will become unequally loaded and it is likely that a strand will become “high”. A high strand condition is illustration in the figure shown at the bottom of the page. In the case shown, selective abrasive wear of the strand will necessitate early removal of the rope.
Poured Sockets- Zinc or Resin
Poured sockets have traditionally been the method for determining the ropes actual breaking strength. All other types of terminations have been compared to poured sockets. Their efficiency is therefore established to be 100% for all grades and constructions of rope
Rope assemblies with poured attachments are generally used as a straight tension where the rope body does not contact the load and is otherwise kept free from distortion or physical abuse. In such cases, where the rope acts as a pendant line, the minimum recommended design factory s 3.0. if the assembly is used as a sling, then the minimum recommended design factor of 5.0 should be used to calculate the rated capacity.
Length tolerances for poured attachments can be somewhat more stringent than other types of assemblies. The manufacturer should be contacted and agreement reached before the order is placed. Tolerance as small as plus or minus 1/8” is not out of the ordinary for this type of assembly. Specifications such as type of fitting, pin orientation, whether zinc or resin should be used, and type of application should also be supplied to the manufacturer when ordering these types of assemblies.
When preparing a wire rope for socketing it is of extreme importance to follow recommended procedures. Those inexperienced in the socketing process should not try to fabricate assemblies without first getting expert training. It is far better to leave fabrication of this type of assembly to the experts.
It is recommended that all poured sockets, whether they are zinc or resin, be proof loaded.
Wire Rope Clips
Wire rope clips are widely used for making end terminators. Clips are available in two basic designs; the U-bolt and fist grip. The efficiency of both types is the same.
When using U-bolt clips, extreme care must be exercised to make certain that they are attached correctly; i.e., the U-bolt must be applied so that the “U” section is in contact with the dead end of the rope. Also, the tightening and retightening of the nuts must be accomplished as required.
Use only forged clips for critical, heavy duty, overhead loads, such as support lines, guy lines, towing lines, tie downs, scaffolds, etc.
Malleable clips are to be used for making eye termination assemblies only with right regular lay wire rope and only for light duty uses with small-applied loads, such as handrails, fencing, guard rails, etc.
How to Apply Clips
Recommended method of applying U-Bolt Clips to get maximum holding power of the clip. The following is based on the use of proper size U-Bolt clips on new rope. See chart on p. 145.
- Turn back specified amount of rope from thimble or loop. Apply first clip one base width from dead end of rope. Apply U-Bolt over dead end of wire rope with live end resting in saddle. Tighten nuts evenly, alternating from one nut to the other until reaching the recommended torque.
- When two clips are required, apply the second clip as near the loop or thimble as possible. Tighten nuts evenly, alternating until reaching the recommended torque. When two or more clips are required, apply the second clip as near the loop or thimble as possible, turn nuts on second clip firmly, but do not tighten. Proceed to step 3.
- When three or more clips are required, space additional clips equally between first two- take up rope slack-tighten nuts on each U-Bolt evenly, alternating from one nut to the other until reaching recommended torque.
- Apply first load to test the assembly. This load should be of equal or greater weight that loads expected in use. Next, check and retighten nuts to recommended torque.
- In accordance with good rigging and maintenance practices, the wire rope and termination should be inspected periodically for wear, abuse and general adequacy. Inspect periodically and retighten to recommended torque.
A termination made in accordance with the above instructions, and using the number clips shown, has an approximate 80% efficiency rating. This rating is based upon the nominal strength of wire rope. If a pulley is used in place of a thimble for turning back the rope, add on additional clip.
The number of clips shown is based upon using right regular or Lang lay wire rope, 6x19 classification or 6x37 classification, fiber core or IWRC, IPS or EIP. If Seale construction or similar large outer wire type construction in the 6x19 classification is to be used for sizes 1 inch or larger, add one additional clip.
The number of clips shown in the chart on page 148 also applies to right regular lay wire rope, 8x19 classification, fiber core, IPS, sizes 1 ½ inch and smaller; the right regular lay wire rope, 19x7 classification, IPS or EIP, sizes 1 ¾ inch and smaller.
For other classifications of wire rope not mentioned above, it may be necessary to add additional clips to the number shown.
If a greater number of clips are used that shown above in the table, the amount of rope turn back should be increased proportionally. Above based on use of proper size U-Bolt clips on new rope.
Important: Failure to make a termination in acco in the table, the amount of rope turn back should be periodically check and retighten to the recommended torque may cause a reduction in efficiency rating.
Fist Grip Clips
Recommended method of applying Fist Grip Clips to get maximum holding power of the clip. The following based on the use of proper size fist grip clips on new rope.
- Turn back specified amount of rope from thimble of loop. Apply first flip one base width from dead end of rope. Tighten nuts evenly, alternating from one nut to the other until reaching the recommended torque.
- When two clips are required, apply the second clip as near the loop or thimble as possible. Tighten nuts evenly, alternating until reaching the recommended torque. When more than two clips are required, apply the second clip as near the loop or thimble as possible. Turn nuts on second clip firmly, but do not tighten. Proceed to step 3.
- When three or more clips are required, space additional clips equally between first two- take up rope slack- tighten nuts on each Fist Grip evenly, alternating from one nut to the other until reaching recommended torque.
- Apply first load to test the assembly. This load should be of equal or greater weight than loads expected in use. Next, check and retighten nuts to recommended torque.
In accordance with good rigging and maintenance practices, the wire rope and termination should be inspected periodically for wear, abuse and general adequacy.
Inspect periodically and retighten to recommended torque.
A termination made in accordance with the above instructions and using the number of clips shown has an approximate 80% efficiency rating. This rating is based upon the nominal strength of the wire rope. If a pulley is used in place of a thimble or turning back the rope, add one additional clip.
The number of clips shown on page 149 is based upon using right regular or Lang lay wire ropes, 6x19 classification or 6x37 classification, fiber core or IWRC, IPS or EIP. If Seale construction or similar larger outer wire type construction in the 6x19 classification is to be used for sizes 1 inch and larger, add one additional clip.
The number of clips shown also applies to the right regular lay wire rope, 8x19 classification, fiber core, IPS, sizes 1 ½ inch and smaller; and right regular lay wire rope, 18x7 classification, fiber core, IPS or EIP, sizes 1 ¾ inch and smaller.
For other classifications of wire rope not mentioned above, it may be necessary to add additional clips to the number shown.
If a greater number of clips are used than shown in the table, the amount of rope turn back should be increased proportionately. Above based on us of proper size U-Bolt clips on new rope.
* Important: Failure to make a termination in accordance with aforementioned instructions, or failure to periodically check and retighten to the recommended torque may cause a reduction in efficiency rating. *
One of the more popular end attachments for wire rope is the wedge socket. For field, or on the job attachment, it is easily installed and quickly dismantled. The following procedures are important for safe application of wedge sockets.
Inspection and Safety
- Always inspect socket, wedge and pin for correct size and condition before using.
- Do not use parts showing cracks.
- Do not use modified or substitute parts.
- Repair minor nicks or gouges to socket or pin by lightly grinding until surfaces are smooth. Do not reduce original dimension more than 10%. Do not repair by welding.
- Inspect permanent assemblies annually or more often in severe operating conditions.
- Consult the socket manufacturer for recommendations regarding the specific use and reapplication of wedge sockets.
- Use only with standard 6 to 8 strand wire rope of designated size. For intermediate size rope, 9/16” diameter and larger, use the next larger size socket. For example: when using 9/16” diameter wire rope use a 5/8” Wedge Socket Assembly. Welding of the tail on standard wire rope is not recommended. The tail length of the dead end should be a minimum of 6 rope diameters.
- Align live end of rope with centerline of pin.
- Secure dead end section of rope.
- Do not attach dead end to live end.
- Use a hammer to seat Wedge and Rope as deep into the socket as possible before applying the first load.
- To use with rotation resistant wire rope (special wire rope constructions with 8 or more outer strands) ensure the dead end is seized, welded or brazed before inserting the wire rope into the wedge socket to prevent core slippage or loss of rope lay. The tail length of the dead end should be a minimum of 20 rope diameters but not less than 6”.
- Apply first load to fully seat with Wedge and Wire Rope in the socket. This load should be of equal or greater weight than loads expected in use.
- Efficiency rating of the Wedge Socket termination is based upon the nominal strength of wire rope. The efficiency of a properly assembled Wedge Socket is 80%.
- During use, do not strike the dead end section with any other elements of the rigging (called two blocking).
- Do not shock load.
The proper direction of winding the first layer on a smooth drum can be determined by standing behind the drum and looking along a path the rope travels. The correct relationship that should be maintained between the direction of the lay of the rope ( right or left) and the direction of rotation of the drum (over wind or under wind), winding from left to right or right to left are important applications of winding.
Drums- Multiple Layers
Many installations are designed with requirements for winding more than one layer or wire rope on a drum. Winding multiple layers presents some further problems.
The first layer should wind in a smooth, tight helix, which, if the drum is grooved, is already established. The grooves allow the operator to work off the face of the drum and permit the minimum number of dead wraps.
A smooth drum presents an additional problem, initially as the wire rope must be wound in such a manner that the first layer will be smooth and uniform and will provide a firm foundation for the layers of rope that will be wound over it. The first layer of rope on the smooth drum should be wound with tension sufficient to assure a close helix-each wrap being wound as close as possible to the preceding wrap and most, if not all, of the entire layer being used as dead wraps. The first layer then acts, as a helical groove with will guide the successive layers. Unlike wire ropes operating on grooved drums, the first layer should not be unwound from a smooth-faced drum with multiple layers.
After the rope has wound completely across the face of the drum (either smooth or grooved), it is forced up to a second lay at the flange. The rope then winds back across the drum in the opposite direction, lying in the valleys between the wraps of the rope on layer, actually winds back one wrap in each revolution of the drum. The rope must then cross two rope “grooves” in order to advance across the drum for each turn. The point at which this occurs is known as the crossover. Crossover is unavoidable on the second the succeeding layers.
At these crossover points, the rope is subjected to severe abrasion and crushing as it is pushed over the two rope “grooves” and rides across the crown of the first rope layer. The scrubbing of the rope as this is happening can easily be heard. There are, however, special drum grooving available that will greatly minimize the damage that can occur at crossover points. (E.g., counterbalance drum grooving*)
Severe abrasion can also be reduced by applying the rule for the correct rope lay (right or left lay) to the second layer rather than to the first layer. It is for this reason that the first layer of a smooth drum should be wound tight and used as dead wraps.
Counterbalance grooving is made so that each wrap of rope winds parallel to the drum flange for a distance less than half the circumference around the drum then follows a short crossover to complete half the drum circumference. The cross over is at an angle with the drum flange and displaces the rope laterally by half the pitch of grooving.
Around the other half of the drum circumference each wrap again winds parallel to the flange for a distance then follows another short crossover to a point one full circumference from the start. At this point the lateral displacement is equal to the full pitch of grooving.
The grooving for this type of winding is similar to the parallel grooving except that half the drum circumference is laterally displaced from the other half the pitch of grooving and between these two halves the grooves make short cross-over to guide the rope properly. The two crossover areas are on opposite sides of the drum or 180 degrees apart.
Since the lateral displacement of each crossover is one half the pitch of grooving, or one half the displacement of the cross over encountered with other types of winding, “throw” of the rope is reduced, decreasing the whipping action. However, if the interval between these displacements happens to match the rope’s vibration cycle, whipping can still become severe because this action is cumulative.
Since the crossover areas are spaced opposite each other or 180 degrees apart, raised portions of the winding caused by vertical displacement at the crossover also occur opposite each other. These raised sections become quite pronounced where many layers are involved and the balancing effect of keeping them opposite gave name to the method.
With counterbalancing winding, the change of layers can be controlled better than with other systems and is preferred when a rope must wind in layers on the drums.