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IMPORTANT WARNINGSREAD ALL WARNINGS BEFORE USING THIS WEBSITE Failure to follow warnings and instructions may result in serious injury or death. |
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Anyone using this website must read and understand all warnings and other information listed below and preceding and/or adjacent product description. The following apply to all of the products on this website. Warnings specific to individual products follow, and can be accessed directly using the Table of Contents above. All products are sold with the express understanding that the purchaser is thoroughly familiar with their correct application and safe use. Use all products properly, in a safe manner and for the application for which they were intended. Edwards Wire Rope assumes no responsibility for the use or misapplication of any product. Responsibility for design and use decisions rests with the user. REMEMBER: ANY PRODUCT WILL BREAK IF ABUSED, MISUSED, OVERUSED OR NOT MAINTAINED PROPERLY. Such breaks can cause loads to fall or swing out of control, possibly resulting in serious injury or death as well as major property damage.
It would be impossible to list all possible dangers and misapplications associated with the use of all products contained on this website. However, in order to promote safe rigging habits, the most common hazards associated with the use of these products are outlined. Working Load Limit This is the term used throughout the website. There are, however, other terms used in the industry which are interchangeable with the term Working Load Limit. These are: WLL, SWL, Safe Working Load, Rated Load Value, Resulting Safe Working Load, and Rated Capacity. Never exceed the Working Load Limit. The Working Load Limit is the maximum load which should ever be applied to a product, even when the product is new and when the load is uniformly applied - straight line pull only. Avoid side loading. All catalog ratings are based upon usual environmental conditions, and consideration must be given to unusual conditions such as extreme high or low temperatures, chemical solutions or vapors, prolonged immersion in salt water, etc. Such conditions or high-risk applications may necessitate reducing the Working Load Limit. The Working Load Limit will not apply if product has been welded or otherwise modified. Matching of Components Components must match. Make certain that componenets such as hooks, links or shackles, etc. used with wire rope (or chain or cordage) are of suitable material size and strength to provide adequate safety protection. Attachments must be properly installed and must have a Working Load Limit at least equal to the product with which they are used. Remember: Any chain is only as strong as its weakest link. Raised Loads Keep out from under a raised load. Take notice of the recommendation from the National Safety Council Accident Prevention Manual concerning all lifting operations:
Do not operate a load over people. Do not ride on loads. Shock Loads Avoid impacting, jerking or swinging of load as the Working Load Limit could be exceeded and the Working Load Limit will not apply. A shock load is generally significantly greater than the static load. Avoid shock loads. Regular Inspections Inspect products regularly for visible damage, cracks, wear, elongation, rust, etc. Protect all products from corrosion. The need for periodic inspections cannot be overemphasized. No product can keep operating at its rated capacity indefinitely. Periodic inspections help determine when to replace a product and reduce rigging hazards. Keep inspection records to help pinpoint problems and to ensure periodic inspection intervals. Due to the diversity of the products involved and uses to which they can be put, it would be counterproductive to make blanket recommendations for inspection procedures and frequency. Best results will be achieved when qualified personnel base their decisions on information from rigging and engineering manuals and on experience from actual use in the field. Frequency of inspection will depend on environmental conditions, application, storage of product prior to use, frequency of use, etc. When in doubt, inspect products prior to each use. Carefully check each item for wear, deformation, cracks or elongation - a sure sign of imminent failure. Immediately withdraw such items from service. Rust damage is another potential hazard. When in doubt about the extent of corrosion or other damage, withdraw the items from service. Destroy, rather than discard, items that have been judged defective. They might be used again by someone not aware of the hazard involved. Additional warnings and information on wire rope, chain, cordage, blocks, and tools can be found in the following sections. These should be read and understood thoroughly before using a particular item. |
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DEFINITIONS Information contained in this catalog is subject to change; all weights and dimensions are approximate. Ratings are stated in short tons (2,000lbs.) or pounds. All dimensions are in inches; all weights are in pounds, unless stated otherwise. Working Load Limit (WLL) The Working Load Limit is the maximum load which should ever be applied to the product, even when the product is new and when the load is uniformly applied - straight line pull only. Avoid side loading. All catalog ratings are based upon usual environmental conditions and consideration must be given to unusual conditions such as extreme high or low temperatures, chemical solutions or vapors, prolonged immersion in salt water, etc. Never exceed the Working Load Limit. Proof Test Load (Proof Load) The term "Proof Test" designates a quality control test applied to the product for the sole purpose of detecting defects in material or manufacture. The Proof Test Load (usually twice the Working Load Limit) is the load which the product withstood without deformation when new and under laboratory test conditions. A constantly increasing force is applied in direct line to the product at a uniform rate of speed on a standard pull testing machine. The Proof Test Load does not mean the Working Load Limit should ever be exceeded. Breaking Strength/Ultimate Strength Do not use breaking strength as a criterion for service or design purposes. Refer to the Working Load Limit instead. Breaking Strength is the average force at which the product, in the condition it would leave the factory, has been found by representative testing to break, when a constantly increasing force is applied in direct line to the product at a uniform rate of speed on a standard pull testing machine. Proof testing to twice the Working Load Limit does not apply to hand-spliced slings. Remember: Breaking Strengths, when published, were obtained under controlled laboratory conditions. Listing of the Breaking Strength does not mean the Working Load Limit should ever be exceeded. Design Factor (sometimes referred to as safety factor) An industry term usually computed by dividing the catalog Breaking Strength by the catalog Working Load Limit and generally expressed as a ratio. For example: 5 to 1. Shock Load A load resulting from rapid change of movement, such as impacting, jerking or swinging of a static load. Sudden release of tension is another form of shock loading. Shock loads are generally significantly greater than static loads. Any shock loading must be considered when selecting the item for use in a system. Avoid shock loads as they may exceed the Working Load Limit. |
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FURTHER EXPLANATIONS AND CAUTIONS IF LIFTING ANGLES ARE INVOLVED Numerical values published for Breaking Strength and Working Load Limit in the catalog are very specific in one point: They refer to straight, in-line pull or force and are obtained under laboratory conditions. There are, however, many applications where a straight line pull is not possible or even desirable. When a tackle block system is reeved, wire rope may be bent over many sheaves; multiple leg wire rope or chain slings involve differing lifting angles; angular loads on shackles or eyebolts alter Working Load Limits of the equipment used. All these and other factors influencing the Working Load Limit must be taken into account when systems are designed and used. The following examples and tables are intended to highlight and demonstrate the effects of angles on the Working Load Limit. CHAIN SLINGS, fabricated entirely from grade 80 alloy components.
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Effect of Angles on Sling Capacities
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WIRE ROPE IS A MACHINE. Understand and respect it. Like any machine, it needs proper care and maintenance for optimal safety and long service life. For a better understanding of wire rope we highly recommend the Wire Rope Users Manual by the Wire Rope Technical Board. Excerpts of that manual have been reprinted in the wire rope section of our products pages. Refer to the General Warnings above. These warnings also apply to wire rope. Only additional warnings and information are listed below. Rated Capacity. Rated capacity is the load which a new wire rope may handle under given operating conditions and at assumed design factor. A design factor of 5 is chosen most frequently for wire rope. (Operating loads not to exceed 20% of catalog Breaking Strength.) Operating loads may have to be reduced when life, limb or valuable property are at risk or other than new rope is used. A design factor of 10 is usually chosen when wire rope is used to carry personnel. (Operating loads not to exceed 10% of catalog Breaking Strength.) Responsibility for choosing a design factor rests with the user. Attachments must have at least the same Working Load Limit as the wire rope used. Clips, sockets, thimbles, sleeves, hooks, links, shackles, sheaves, blocks, etc. must match in size, material and strength to provide adequate safety protection. Proper installation is crucial for maximum efficiency and safety. Keep out from under a raised load. Do not operate loads over people. Do not ride on loads. Conduct all lifting operations in such a manner that if equipment were to fail or break, no personnel would be injured. This means KEEP OUT FROM UNDER A RAISED LOAD, DO NOT OPERATE LOADS OVER PEOPLE AND KEEP OUT OF THE LINE OF FORCE OF ANY LOAD. Avoid shock loads. Avoid impacting, jerking or swinging of load. Working Load Limit will not apply in these circumstances because a shock load is generally significantly greater than the static load. Inspect wire rope regularly. Use inspection instructions as guidelines only. Two of the most important prerequisites for inspecting wire rope are technical knowledge and experience. Check the general condition of the wire rope. Also, look for localized damage and wear, especially at wire rope attachments. Inspect all parts that come in contact with the wire rope. Poor performance of wire rope can often be traced back to work or wrong-sized sheaves, drums, rollers, etc. Look for kinks, broken wires, abrasions, lack of lubrication, rust damage, crushing, reduction of diameter, stretch or other obvious damage. If any of these conditions exist or if there is any other apparent damage to the wire rope, retire the wire rope according to the instructions below. When in doubt about the extent of the damage, retire the wire rope in question immediately. Without laboratory analysis, it is impossible to determine the strength of damaged or used wire. Thus, you will not be able to tell whether wire rope with any amount of damage is safe to use. Retire the wire rope that is damaged. For specific inspection procedures check various OSHA and ANSI publications. Destroy, rather than discard, wire rope to be retired. Wire rope that is not destroyed might be used again by someone not aware of the hazard associated with that use. Destroying wire rope is best done by cutting it up into short pieces. Refer to General Information on Wire Rope below for important characteristics and properties of wire rope. |
GENERAL INFORMATION ON WIRE ROPE  The three basic components of a typical wire rope. (Fiber core is shown.) COMPONENTS: Wire rope consists of three basic components. 1. Wires. 2. Strands, formed by wires, laid helically around a core. 3. Core, or center. MATERIAL: Steel grades in wide use today are IPS (improved plow steel), EIPS (extra improved plow steel), sometimes also referred to as XIPS, XIP, or EIP, as well as EEIPS (extra, extra improved plow steel.) CORE: Its function is to provide proper support for the strands under normal conditions. Three types of core (or center) are commonly used. 1. Fiber Core (F.C.), usually polypropylene (P.C.), sometimes hemp (H.C.) and sisal. 2. Independent Wire Rope Core (IWRC) 3. Wire Strand Core (WSC) IWRC and WSC are sometimes referred to as steel wire core or steel center. CONSTRUCTION: Expressed in numbers of strands x number of wires. 6 x 25 indicates that the wire rope consists of 6 strands, which in turn have 25 individual wires. Constructions are grouped into classes: 6 x 7 Class: Containing 6 strands that are made up of 3 through 14 wires, of which no more than 9 are outside wires. 6 x 19 Class: Containing 6 strands that are made up of 15 through 26 wires, of which no more than 12 are outside wires. 6 x 36 Class: Containing 6 strands that are made up of 27 through 49 wires, of which no more than 18 are outside wires. 8 x 19 Class: Containing 8 strands that are made up of 15 through 26 wires, of which no more than 12 are outside wires. 19 x 7 Class: Containing 19 strands, each of which is made up of 7 wires. 8 x 19 and 19 x 7 class wire ropes have rotation-resistant properties, excluding elevator ropes. Other common constructions are 7x7 and 7x19 galvanized cable, which is sometimes referred to as "aircraft cable" although it is not intended for aircraft use. Also, 1x7 and 1x19 strand wire ropes, as well as 7x7x7, 7x7x19 cable-laid wire ropes. Many others exist, some for highly specialized applications only. Note that any class denotes the nominal number of wires in each strand. The actual number of wires may be different. For example, 6x36 class: strands most commonly consist of 36 wires, or 31, or 41. STRAND PATTERNS: They refer to different types of arrangements of wires and their diameters within a strand. Common strand patterns are Filler Wire, Seale, Warrington and combinations thereof. LAY: Indicates how the wires have been laid to form strands and how the strands have been laid around the core. A right regular lay rope (RRL; the most common) has its strands laid right on the rope - similar to threading a right-hand threaded bolt. Regular means that the direction of the wire lay in the strand is opposite to the direction of the strand lay in the rope. (The wires in regular lay rope appear to be in line with the axis of the rope). Caution: When combining seperate ropes in a single line application always use ropes of the same lay pattern. Different lays can increase rotation at connection points decreasing rope efficiency.
PREFORMING: A manufacturing process wherein the strands and their wires are permanently formed - during fabrication - to the helical shape that they will ultimately assume in the finished wire rope. Proper preforming prevents the strands and wires from unlaying during normal use. The vast majority of wire rope sold today is preformed. FINISH: Wire rope is either sold as "bright" (or "black") - meaning uncoated, or galvanized for better corrosion resistance. "Drawn Galvanized" wire has the same strength as bright wire, but wire, "galvanized at finished size" is usually 10% lower in strength. Plastic coated wire rope is also available, usually galvanized or stainless steel cable. The most common plastic coatings are nylon in either clear or white, although other materials and colors are available. These coatings do not add strength to the wire rope itself. LUBRICATION: During fabrication, wire ropes receive lubrication. The kind and amount depends on the rope's size, type and use, if known. This in-process treatment will provide the finished wire rope with ample protection for a reasonable time if it is stored under proper conditions. But, when the wire rope is put into service, the initial lubrication will normally be less than needed for the full useful life of the wire rope. Because of this, periodic applications of a suitable wire rope lubricant are necessary. ORDERING WIRE ROPE: Construction, lay, core, finish and other factors mentioned above impart greatly differing characteristics to different wire ropes. They must be understood and considered when selecting wire rope. There is no perfect wire rope for all applications; usually some less desirable properties are traded off for other, more desirable ones. Refer to the Wire Rope Users Manual by the Wire Rope Technical Board for a better understanding of wire rope properties and consult professional help when in doubt. Lacking a complete description of the wire rope desired, a supplier can make several assumptions: 1. If direction and type of lay are omitted from the rope description, it is assumed to be right regular lay (RRL). 2. If finish is omitted, this will be presumed to mean ungalvanized, "bright" finish. 3. If no mention is made with reference to preforming, preformed wire rope will be supplied. 4. If a supplier receives an order for 6 x 19 wire rope he may assume this to be a class reference and is, therefore, legally justified in furnishing any construction within this category. |
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PROPER HANDLING OF WIRE ROPE MEASURING OF WIRE ROPE
How to measure (or caliper) a wire rope correctly. Since the "true" diameter (A) lies within the circumscribed circle, always measure the larger dimension (B). Actual diameter can be 5% larger than nominal wire rope diameter. RECEIVING AND STORING WIRE ROPE Make certain that the wire rope received is the one that was ordered. Check for obvious damage to wire rope and reel. Store wire rope away from heat, moisture and other corrosive agents. This means storing under a weatherproof cover, off the ground, preferably in a dry, cool, well ventilated warehouse. If wire rope has to be kept outdoors, cover it with a coating of protective wire rope lubricant and cover both wire rope and reel with waterproof material. Keep it well off the ground. Careful inspection after extended storage is of utmost importance. UNREELING OR UNCOILING WIRE ROPE Great care must be taken when removing wire rope from reels or coils. Looping the rope over the flange of the reel or pulling the rope off a coil while it is lying on the ground will create loops in the line. If these loops are pulled tight, kinks will result, thereby permanently damaging the wire rope. Check illustrations below showing correct and incorrect ways of unreeling and uncoiling wire rope. Whenever handling wire rope, take care not to drop reels or coils. This can damage wire rope and collapse the reel, making removal of the wire rope extremely difficult if not impossible.
REREELING WIRE ROPE When reeling wire rope from one reel to another it is preferable for the wire rope to travel from top to top, as illustrated. Spooling from bottom to bottom is also acceptable, provided the surface over which the wire rope will travel is clean, smooth and dry, so as not to allow foreign particles to become embedded in the wire rope. Spooling from top to bottom or from bottom to top can put a reverse bend into wire rope and must be avoided. When stringing up on machinery wire rope should be removed from the reel in the same direction as placed on the drum.
CUTTING AND SEIZING WIRE ROPE There are numerous ways to cut wire rope - use only appropriate tools specifically designed to cut wire rope. Safety goggles and work gloves must always be worn. Observe other precautions peculiar to the tools used. Wire rope should be properly seized on both sides of the cut with wire or strand. Seizing wire diameter and the number and length of the seizings will depend on the diameter of the wire rope, and whether or not it is preformed. BREAKING IN NEW WIRE ROPE Since wire rope is a machine with many moving parts, it requires careful installation and breaking in procedures for maximum safety and long service life. After proper installation, allow the wire rope to run through a cycle of operation at a very low speed. Keep a close watch on the wire rope, its attachments and any working parts such as sheaves, drums, rollers, etc. to make certain that the wire rope runs freely. If no problems appear at this stage, run the wire rope through several cycles of operation under light load at reduced speed. This procedure allows the component parts of the new rope to make a gradual adjustment to the actual operating conditions. WIRE ROPE EFFICIENCY Wire rope will develop 100% efficiency, that is, break at or above minimum acceptance strength (not less than 2 1/2% below nominal breaking strength) under controlled laboratory conditions. Once fittings such as sleeves, clips, sockets, etc. are attached and/or the wire rope passes over a curved surface such as sheaves, pins, etc. its strength is decreased. In the case of wire rope passing over a curved surface this decrease in strength depends on the severity of the bend. In the case of wire rope fittings, the decrease in wire rope strength will depend on the type of fittings used. The wire rope efficiency usually ranges from 70% - 100%. For more detailed information consult the strength efficiency of wire rope graph here. Note, that hand spliced wire rope, while not using any fittings, has less efficiency than properly flemished and swaged wire rope. There are other factors, depending on the application of wire rope, that can cause a decrease in nominal wire rope strength. They must be considered when choosing a design factor. Refer to the Wire Rope Users Manual and/or other qualified sources for details. ELASTIC PROPERTIES OF WIRE ROPE Wire rope is an elastic member; it stretches or elongates under load. This elongation can be permanent or recoverable. The extent of elongation will depend on the wire rope used and the design factor chosen. While it may be acceptable for many wire rope uses to neglect its elastic properties, they are of critical importance for some uses. When in doubt about the importance of wire rope elongation consult professional help. Pre-stretching wire rope will only remove some of the constructional stretch and will not totally eliminate elongation under load. WINDING WIRE ROPE ON DRUMS Installation of wire rope on a plain or grooved drum requires a great deal of care. Make certain the wire rope is properly attached to the drum. Keep adequate tension on the wire rope as it is wound onto the drum. Guide each wrap as close to the preceding wrap as possible, or follow the groove in case of a grooved drum. No blanket recommendations can be given concerning direction of winding, desirable drum diameter, fleet angle, etc. Consult the Wire Rope Users Manual for this and other important technical information. WIRE ROPE SLINGS Refer to ASME standard B30.9 and OSHA standard 1910.184 for design factors and other important information. Other standards and information may apply. |
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REEL CHART Listed below are some of the most commonly used reels in our inventory and the approximate lengths of wire rope that will fit on the reels.
REEL CAPACITY Due to tolerances on diameters and variety of constructions of wire rope, it is difficult to calculate the maximum length of wire rope that can be spooled on a reel or drum. The formula below may be used to calculate reel capacities with at least one wire rope diameter below the flange diameter, for clearance ("X"). Calculated reel capacities are based on uniform rope winding on the reel.
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IMPORTANT WARNINGS
Failure to follow warnings and instructions can result in serious injury or death.
Refer to the General Warnings above. These warnings also apply to chain and chain assemblies. Only additional warnings and information are listed below. Never exceed the Working Load Limit of the chain. The Working Load Limit is the maximum load that should ever be applied to the chain, even when new and when the load is uniformly applied. Working Load Limit applies only to straight line pulls. When using multiple leg chain slings, the Working Load Limit of each leg will have to be reduced considerably depending on the angle of the sling legs. See here for further discussion. Consult industry recommendations for information, such as ASME B 30.9. When in doubt as to the Working Load Limit of the chain, refer to the periodic, permanently embossed grade marking on chain links. Proof Coil Chain is identified by P.C. or 30 or 3 or 28; HighTest Chain by H.T. or 43 or 40 or 4; Transportation Chain by 70 or 7; Alloy Chain by 80 or 8 or 800. Use only alloy chain for overhead lifting. Grade 80 alloy chain is the only type of chain which can be used for overhead lifting. Use only grade 80 alloy fittings for overhead lifting. Attachments must have at least the same Working Load Limit as the chain used. Hooks, links, shackles, etc. must be of suitable material and strength to provide adequate safety protection. Keep out from under a raised load. Do not operate load over people. Do not ride on loads. Conduct all lifting operations in such a manner that if equipment were to fail or break, no personnel would be injured. This means KEEP OUT FROM UNDER A RAISED LOAD, DO NOT OPERATE LOADS OVER PEOPLE AND KEEP OUT OF THE LINE OF FORCE OF ANY LOAD. Avoid shock loads. Avoid impacting, jerking or swinging of load. Working Load Limit will not apply in these circumstances because a shock load is generally significantly greater than the static load. Inspect chain frequently. No product can keep operating at its rated capacity indefinitely. Closely examine each link for deformation, cracks, elongation, corrosion, rust, etc. Take chain out of service even if only one bad link is found. Eliminate twists and kinks in chain before using. Do not attempt to repair damaged or worn links in a chain. Do not attempt to weld, anneal, heat treat or hot galvanize alloy chain - its capacity will be completely destroyed. Protect chain from corrosion. Destroy, rather than discard, chain that is judged to be defective. Chain that is not destroyed might be used again by someone not aware of the hazard associated with that use. Destroying chain is best done by cutting it up into short pieces. Chain Slings Only grade 80 alloy chain can be used for overhead lifting. Refer to OSHA standard 1910.184 and ASME standard B30.9 for design factors and other important information. Other standards and information may apply depending on specific use. |
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CAUTION: NEVER EXCEED THE WORKING LOAD LIMIT
Failure to follow warnings and instructions can result in serious injury or death. Read important warnings and information in preceding General section as well as following Fittings section.
LOAD BINDERS, LEVER TYPE
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IMPORTANT WARNINGS
Failure to follow warnings and instructions can result in serious injury or death.
Refer to the General Warnings above. These warnings also apply to fittings. Only additional warnings and information are listed below. Never exceed the Working Load Limit. The Working Load Limit is the maximum load which should ever be applied to the product, even when the product is new and when the load is uniformly applied - straight line pull only. Avoid side loading. All catalog ratings are based upon usual environmental conditions, and consideration must be given to unusual conditions such as extreme high or low temperatures, chemical solutions or vapors, prolonged immersion in salt water, etc. Such conditions or high-risk applications may necessitate reducing the Working Load Limit. Working Load Limit will not apply if product has been welded or otherwise modified. Match components properly. Make certain that components such as hooks, links or shackles, etc. used with wire rope (or chain or cordage) are of suitable material and strength to provide adequate safety protection. Attachments must be properly installed and must have a Working Load Limit at least equal to the product with which they are used. Keep out from under a raised load. Conduct all lifting operations in such a manner, that if there were an equipment failure, no personnel would be injured. This means keep out from under a raised load and keep out of the line of force of any load. Do not operate load over people. Do not ride on loads. Avoid shock loads. Avoid impacting, jerking or swinging of load as the Working Load Limit could be exceeded and the Working Load Limit will not apply. A shock load is generally significantly greater than the static load. Inspect products regularly. No product can keep operating at its rated capacity indefinitely. Periodic inspections help determine when to replace a product and reduce rigging hazards. Check for visible damage, cracks, wear, elongation, rust, corrosion, etc. When in doubt about the extent of the damage, retire the item in question immediately. Destroy, rather than discard, items that have been judged defective. They might be used again by someone not aware of the hazard associated with use. |
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Read important warnings and information below and preceding Fittings section. Failure to understand and follow the instructions outlined below can result in serious injury or death.
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CORRECT METHOD OF INSTALLING U-BOLT WIRE ROPE CLIPS
1. Turn back specified length of rope from thimble and apply first clip one saddle width from seized dead end. Tighten nuts evenly to specified torque. Important: seat "live end" of wire rope (load carrying part) in saddle and position u-bolt over "dead end." |
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2. Apply second clip close to the thimble without binding on it. Turn on nuts firmly but do not tighten yet to recommended torque. |
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3. Apply all other clips, equally spaced between first two clips. |
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4. Apply light tension and tighten all nuts evenly to specified torque. 5. Recheck and re-tighten nuts after initial load. This load should be at least equal to loads expected in general use. Wire rope will stretch slightly causing a reduction in diameter which will slacken the clips. Nuts must be checked at frequent intervals for tightness to assure efficiency of termination. |
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If the specified number of clips are applied according to these instructions, they will develop approximately 80% efficiency of right lay wire rope of classes 6x19, 6x36, 7x19, 8x19, 19x7 and cable-laid. Add at least one additional clip if thimble is not used or if clips are used on other wire ropes than those mentioned above. Check with wire rope manufacturer if in doubt. If more clips are used than specified, the amount of wire rope to be turned back has to be increased proportionately.
Caution: Never use any wire rope clip to directly connect two straight lengths of wire rope. Failure to apply wire rope clips as specified or failure to retorque nuts periodically can result in load release or failure of the assembly resulting in injury or death.
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CAUTION: NEVER EXCEED THE WORKING LOAD LIMIT. Read important information below and here. READ THE FOLLOWING WARNINGS AND SAFETY INFORMATION CAREFULLY. EVEN EXPERIENCED PERSONNEL NEED TO UNDERSTAND THIS INFORMATION. Failure to follow warnings and instructions can result in serious injury or death.
Blocks are devices used for lifting or lowering loads, or for changing direction of the pull on the line. They consist of a sheave, two side plates, and an end fitting which is either a hook with a latch or a shackle.
WARNING Improper use or set-up of a block system can cause a load to slip or fall, resulting in serious injury or death. A block assembly should always be rigged by someone with training and experience in designing and assembling these systems. If you do not understand how to rig properly or how to operate block systems, seek professional assistance. Also, the following statements should always be followed in order to prevent serious injury or death:
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IMPORTANT SAFETY INFORMATION
ASSEMBLY:
A number of potential hazards exist when working with blocks. These hazards can cause serious harm to both humans and property. However, these hazards can be avoided if the block systems are assembled, used, and maintained properly. The following directions should ALWAYS be followed in order to prevent serious injury or death.
- Always make sure that the hook supports the load. The latch must NEVER support the load.
- Always check for wear or damage before rigging block systems. Check for cracks, rust, corrosion, deformation, intentional alterations, chips, warps, or any other physical signs of damage or wear. When in doubt about the extent of wear or damage to a product, take the product out of service immediately. Only laboratory tests can determine the fitness of a damaged or worn part. Thus, you may not be able to tell whether a part with any amount of damage is safe to use. Discard any part that appears worn or damaged.
USE:
- Know and follow OSHA rules.
- Know the weight of the load and the line pull required.
- Make sure that the correct wire rope grade and diameter is used. Consult Wire Rope product page for information.
- Never exceed the Working Load Limit (WLL). The Working Load Limit indicated is the greatest force or load a product can carry under usual environmental conditions. Shock loading and/or extraordinary conditions must be taken into account when selecting products for block systems and especially in determining the Working Load Limit for a specific application.
- The Working Load Limit of a product is affected by many factors. Among these are: Overloading, misuse, intentional abuse or alteration, corrosion, deformation, operation in extreme environments, and simply wear. In order to determine whether the product can continue to be used at the published WLL, regular inspections must be performed. These inspections also will determine whether a product must be withdrawn from service.
- Avoid side loading blocks. These products generally are intended for tension or pull. Side loading must be avoided, as it exerts additional force or loads which the product may not be able to withstand.
MAINTENANCE:
In order to ensure peak efficiency and extended service life it is necessary that blocks be inspected and maintained at frequent intervals. Consider the following points:
- Inspect products for any signs of wear or damage. These include:
- Worn sheaves, bushings, side plates, pins, hooks, or shackles.
- Hook latch for proper fit and operation. Deformed latches must be replaced.
- Deformed side plates, pins, hooks, and shackles. Worn, deformed or damaged parts of the block and any other part used in the assembly must be replaced. If necessary, the entire assembly needs to be removed from service.
- Blocks supplied by Edwards Wire Rope are furnished with bronze bushings. This type of bushing is not self-lubricating. These blocks are intended for infrequent and intermittent use with low line speeds. Follow this lubrication schedule as a minimum.
- Moderate use: Every 8 hours.
- Intermittent operation: Once a week.
- Rotate sheave during lubrication process.
LOADS
Throughout this catalog the term Working Load Limit is used. It refers to the maximum load or force which a product is designed to support in general service when the pull is applied in-line. There are, however, other terms used in the industry which are interchangeable with the term Working Load Limit. These are:
- WLL
- SWL
- Safe Working Load
- Rated Load Value
- Resulting Safe Working Load
- Rated Capacity
Other terms applicable, such as Shock Load, Proof Load, and Design Factor are discussed in detail in the General Warnings section.
IMPORTANT:
The total load on the snatch block, and therefore also on any fitting which is attached to the block, is usually considerably greater than the actual load lifted. The deciding factor in determining the total load on the block is the angle between the lead line and the load line.
Multiplication Factors for Snatch Blocks* |
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Lead/Load Line Angle |
Factor |
Lead/Load Line Angle |
Factor |
Lead/Load Line Angle |
Factor |
0° |
2.00 |
60° |
1.73 |
130° |
.84 |
10° |
1.99 |
70° |
1.64 |
135° |
.76 |
20° |
1.97 |
80° |
1.53 |
140° |
.68 |
30° |
1.93 |
90° |
1.41 |
150° |
.52 |
40° |
1.87 |
100° |
1.29 |
160° |
.35 |
45° |
1.84 |
110° |
1.15 |
170° |
.17 |
50° |
1.81 |
120° |
1.00 |
180° |
.00 |
TOTAL LOAD ON BLOCK = ACTUAL LOAD LIFTED X MULTIPLICATION FACTOR*
*Use these multiplication factors for single line systems only.
EXAMPLES:
A load weighing 4 tons is pulled straight up. Observe how the TOTAL LOAD on the block differs when the angle between the lead line and the load line changes.
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The truck shown at right is lifting a 1000 lb. weight. Load on block A: 1000lbs. x .92 = 920 lbs. Load on block B: 1000lbs. x 1.77 = 1770lbs. |
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MATCH WIRE ROPE OR FIBER ROPE TO SHEAVE.
Using rope of different size than the one for which the sheave is grooved is potentially dangerous and will cause rapid wear of both sheave and rope.
INSPECT BLOCKS FREQUENTLY.
Check general condition of block componenets. Look for wear on sheave grooves, sheave pins, wobble of sheave, security of bolts and nuts, etc. Make sure sheave rotates freely and lubricate grease nipples frequently.
BEWARE THAT BENDING ROPE OVER SHEAVES WILL REDUCE ITS STRENGTH.
The smaller the ratio of sheave diameter to rope diameter the larger the reduction in rope strength efficiency compared to the Catalog Breaking Strength, and the more rapid the resulting wear on sheave and wire rope fatigue. Avoid changing the bending direction from one sheave to another, as this will rapidly accelerate rope fatigue.
D: sheave pitch diameter / d: wire rope diameter
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IMPORTANT WARNINGS
Failure to follow warnings and instructions can result in serious injury or death.
Refer to General Warnings and Information here. These warnings also apply to cordage (rope). Only additional warnings and information are listed below. Never exceed the Working Load Limit of rope. Use Working Load Limits as published as guidelines only. Working Load Limit may have to be reduced when life, limb or valuable property are at risk, or other than new rope is used. When using multiple leg rope slings, the Working Load Limit of each leg will have to be reduced considerably. Consult industry recommendations for information such as published by the Cordage Institute. Working Load Limit does not apply if rope has been subjected to severe dynamic loading, which may not be visible. Avoid overheating. Exposure to high temperatures will cause ropes to lose strength rapidly. Even temperatures as low as 150° F (66° C) can reduce the strength of some ropes by 50%. When using synthetic rope (especially polypropylene) on a capstan or a winch, be careful to avoid excessive friction which heats, melts and fuses the outer fibers of the rope. Avoid repeated surging or hard rendering around poles or over cross arms. Polyester rope resists overheating best because its melting point is highest. Attachments must have at least the same Working Load Limit as the rope used. Hooks, links, shackles, etc. must be of suitable material and strength to provide adequate safety protection. Splice rope properly and use thimbles if applicable. Choose rope to match gear or gear to match rope. Sheaves, pulleys, thumbles, etc. that do not match the size of rope being used can cause dangerous friction, abrasion, overload, etc. Keep out from under a raised load. Do not move load over people. Do not ride on load. Conduct all lifting operations in such a manner that if equipment were to fail or break, no personnel would be injured. This means KEEP OUT FROM UNDER A RAISED LOAD, DO NOT OPERATE LOADS OVER PEOPLE AND KEEP OUT OF THE LINE OF FORCE. Avoid shock loads. Rope that is strong enough to withstand a steady pull can be broken with a sudden jerk. Be aware of all possible dynamic loading situations. Avoid them when possible and allow for strong enough rope when they cannot be avoided. Keep in mind that the effects of dynamic loading are greater on shorter ropes than on longer ones and greater on low elongation ropes (such as Manila and polypropylene) than on high elongation rope (such as nylon). Never stand in the line of rope under strain. If the rope breaks it will recoil with considerable force, especially if it is nylon. Inspect rope frequently. Closely examine entire length of rope for damage to determine general condition and detect localized wear. Excessive abrasion, fusing of outside fibers, hockles, rust or other chemical stains, broken fibers or other obvious damage to rope are reasons to retire rope from service. Internal damage can be assessed by twisting strands open and checking for powdered fiber. Rope that is suspected of having been exposed to severe shock loads or loads close to its catalog Breaking Strength should be retired immediately. Such damage may not be visible. Actual remaining strength of damaged rope or used rope can only be established by laboratory analysis and tension tests. Destroy, rather than discard, rope to be retired. It might be used again by someone not aware of the hazard or defect. This is best achieved by cutting it up into short pieces. Rope Slings Refer to OSHA standard 1910.184 and ASME standard B30.9 for design factors and other important information. Other standards and information may apply in specific applications. |
Avoid abrasion and unnecessary wear.
Outer fibers as well as inner fibers contribute to a rope's strength. When outer fibers are worn by chafing or dragging over splintered, rough or gritty surfaces, the rope is worn and weakened. When rope is used on cleats, winchheads, etc. make sure they are smooth and use chafing gear if necessary.
Avoid sharp angles and bends.
Sharp angles greatly affect the strength of a rope. Any sharp angle or bend is a weak spot. Use thimbles or chafing gear or padding where possible. Knots are also weak spots. They can reduce strength by as much as 50% or more. Use splices instead. Splice rope correctly. When a small section of rope has been worn or damaged, cut out the section and splice it together. Splice in extra tucks for synthetic fiber ropes. Use proper splicing procedures as outlined by the Cordage Institute. Do not resplice rope that broke due to being overloaded - discard it instead. Its remaining strength will only be a fraction of the Working Load Limit when new. Prevent unraveling of rope - whip or tape cut ends.
Avoid sustained loads.
Fiber ropes subjected to heavy loads for long periods of time can break well below catalog Breaking Strength. Natural fiber ropes such as Manila and Sisal have less ability to take sustained loafs than synthetic fiber ropes such as nylon or polypropylene. Never exceed the Working Load Limit and do not subject fiber rope to sustained loads for more than two days.
Avoid rust.
All ropes, synthetic or natural, should be kept away from rusting iron or steel. Rust can cause rapid loss of strength, sometimes in as short a time as one to two weeks. If ropes become rust stained, inspect the extent of the stain. If it is halfway through the rope, then rope strength may be reduced by as much as 50%
Keep rope away from chemicals.
Even though synthetic rope is generally considered to be resistant to damage from oils, gasoline, paint and most chemicals, exposure to any of these may cause some damage. Avoid contact with such things as storage battery solution, washing compounds or solutions, and animal wastes. Strong acids, alkalis and solvents can damage any rope. Natural fiber rope is extremely vulnerable to all chemicals and solvents.
Avoid the use of swivels in ropes under load.
A loss of turn will cause permanent damage to the rope.
Never use a nylon line which has a high stretch factor in combination with another rope of low stretch.
The nylon line will stretch and not carry its proportionate share of the load, thus putting extra strain on the other lines.
Reverse ends of the rope periodically.
Especially in tackles and winches, reverse the rope end-for-end periodically so that all sections will be worn equally. Also, using a line in one direction over a winch many times can also damage the rope by twisting it too tight or untwisting it so that hockles occur. Kinks pulled through a restricted space such as a tackle block, can seriously damage rope fibers. The initial use should be in a clockwise direction, then reverse the rope periodically.
Slack off guys in wet weather.
When ropes are used as guy lines or other supports exposed to weather, they should be slacked off in wet weather, or damage to the rope, as well as what it is supporting, may result.
Store rope properly.
Rope is best stored in a dry, unheated place where air circulates freely, off the floor and away from direct sunlight and other contact with the elements. Keep in mind that synthetic ropes will deteriorate in direct sunlight due to exposure to ultraviolet radiation. Light colored polypropylene especially is severely affected, smaller diameters more so than larger sizes. Natural fiber ropes (Manila and Sisal) will deteriorate in storage even under ideal conditions.
Dry rope properly.
Whenever natural fiber ropes become wet they should always be thoroughly dried before they are stored or they will rot in a very short time. Do NOT dry synthetic fiber rope in direct sunlight.
Keep rope clean.
Dirt on the surface of the rope can become embedded inside and act as an abrasive on fibers. When rope gets dirty, wash it thoroughly with clean fresh water. Remember to dry natural fiber rope before storing.
Remove rope from coils and reels properly.
Regular right hand laid rope should be uncoiled in a counter clockwise direction.
Coiled rope: Lay the coil on the floor with the inside end at the bottom, then reach down through the center and pull the inside up through the coil.
Reeled rope: Remove the rope from a reel by pulling it off the top while the reel is free to rotate. Rope should never be taken from a reel lying on its end because it is more likely to kink or hockle or pull yarns on the wooden flange.
When substituting natural fiber rope with synthetic fiber ropes (or substituting one synthetic rope for another) substitution should not be made on a straight breaking strength-for-breaking-strength basis only. Other important factors must be considered.
Consult the Cordage Institute for additional information.