Rigging Tips: avoid common wire rope damage

common-wire-rope-damage-wire-rope-slings

Wire rope has many applications—today the focus is on Wire Rope slings. Read on for tips from our Brampton rigging experts to inspect your wire rope sling and prevent common wire rope damage, so your wire rope slings have a long life.

Wire Rope: basic components

A piece of wire rope has three main components. Individual wires that make up each strand, the strand itself and finally, the core it’s built around. (See figure 1). The core is typically composed of fibre core (FC) or steel wire core, called independent wire rope core (IWRC). The steel core increases strength by 7% and the weight by 10%, which provides more support to the outer strands than fibre cores. Steel cores resist crushing and are more resistant to heat.

The design factor of wire rope tells you the ratio between minimum breaking load of the rope and the working load limit (WLL).

Figure 1

Wire Rope Lay Patterns

wire-rope-lay-patterns
(L-R) Right Lay/Ordinary Lay, Left Lay/Ordinary Lay, Right Lay/Lang’s Lay, Right Lay/Reverse Lay (Cross Lay)

 

 

 

 

 

Wire Rope Sling Inspection: what to look for

It’s important to inspect your wire rope sling before use to prevent common wire rope damage—but also for safety. Wire rope slings don’t normally pass around a pulley, therefore it’s important to look out for wear from the environment, like:

  • Abrasive dust, little to no lubricant
  • Normal wear-and-tear
  • Corrosion (look for discolouration, lack of flexibility and rough to-the-touch feel)
  • Abrasion
  • Thermal damage (over-heating)
  • Termination failures

When inspecting the wire rope itself, look for wear at the crown, the core strands and inter-strand wear. Check for kinked, damaged or broken wires. This kind of damage is often caused by slinging a previous load incorrectly—if excessive wear is present, it may be best to look at how wire rope slings are used on the worksite. Keep reading for tips to avoid common wire rope damage and wear and tear on slings.

Wire Rope Sling Don’ts:

  • Don’t join slings by threading eyes;
  • Don’t pull loops in your sling or use a knotted/kinked sling;
  • Don’t tie knots in sling legs to reduce length;
  • Don’t overload the sling;
  • Don’t pull from under a load;
  • Don’t life a container with only two slings;
  • Don’t place slings near welding/cutting operations;
  • Don’t force the eye to open more than 20° (this places undue tension on the ferrule;
  • Don’t stand under a load;
  • Don’t land the load directly on the sling;
  • Don’t wrap a wire rope around a hook—this kinks the wire and ruins the sling.

Wire Rope Sling Do’s:

  • Always use a shackle with at least the same SWL to join slings together;
  • Use suitable storage/packaging;
  • Minimum radius sling can be bent is 3 times diameter of sling wire rope.

Most damage to wire rope slings is caused by unnecessary chaffing against the load, ground or nearby objects. Avoid abrasion and don’t place your sling in contact with adjacent structures, don’t drag your wire rope sling from under a load, and avoid double-choke hitching to prevent common wire rope damage.

Wire rope sling corrosion is a major cause of deterioration, and is caused by poor storage, exposure to weather and corrosive chemicals. Thermal damage happens when the operating temperature is too high, electric arching was used during welding or if the sling was exposed to lightening. External wear can typically be seen from the outside, however, it’s more difficult to asses internal damage—the rope must be opened up. See figures 2 and 3 for examples of internal wire rope corrosion.

Internal wear is most affected by pressure and friction. Factors that affect internal wear include:

  • Level of rope tension
  • Bending ratio
  • Bending frequency
  • Lack of lubricant
  • Tension fatigue (affected by degree of tension)
wire-rope-slings-rigging-equipment
Figure 2
wire-rope-slings-rigging-equipment
Figure 3

 

 

 

 

 

 

 

 

Wire Rope termination: what to look for

  • Wire breaks
  • Corrosion
  • Reduction in rope diameter
  • Unusual rope movement
  • Evidence of rope end
  • Evidence of any incorrect fitting
  • Evidence of any component wear

Avoid Common Wire Rope Damage: battening down

When a rigger strikes the eye of a sling in a choke hitch to force the bright closer to the load in an attempt to ‘make it more secure’—this is known as battening down (not to be confused with a batten from theatre rigging), and is actually very dangerous. The bight should always assume its natural angle, which is usually about 120°.

wire-rope-slings-rigging-equipment
Battening down: dangerous!

Practice inspections and know what to look for, avoid battening down, avoid exposing your wire rope sling to abrasive forces and chemicals, and you can avoid common wire rope sling damage.

Want more wire rope? Check out our pages on types of wire rope construction and wire rope grades.

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Hercules SLR is part of the Hercules Group of Companies which offers a unique portfolio of businesses nationally with locations from coast to coast. Our companies provide an extensive coverage of products and services that support the success of a wide range of business sectors across Canada including the energy, oil & gas, manufacturing, construction, aerospace, infrastructure, utilities, oil and gas, mining and marine industries.

Hercules Group of Companies is comprised of: Hercules SLRHercules Machining & Millwright ServicesSpartan Industrial MarineStellar Industrial Sales and Wire Rope Atlantic.

Steel Cable: market growth driven by automotive industry

steel-cable-wire-rope-filaments

The steel cable or wire rope market expects to grow at a CAGR (compound annual growth rate) of 4.2% in the coming period heading into 2023, reports PR Newswire.

Wire rope or steel cable provides strength, flexibility and has many applications. Steel cable is used in elevators, rigging and lifting applications, theatre sets, and is used as a reinforcing material for automotive tires and conveyor belts.

Filaments, which are fine strands of steel are significantly useful for the fabrication of automotive tires. Advantages of wire rope or steel cable filaments include high thermal resistance a better travelling performance. Currently, the global wire rope market is being greatly influenced by market entrants in the automotive industry.

steel-cable-wire-rope
Example of fraying wire rope—notice the individual strands that make up each rope.

Right now, technology and a need for lighter tires are two growing demands in the automotive industry. Flat-run tires, eco tires and nitrogen tires are three examples of tech-driven tires that create a demand for a flashier, updated tires for manufacturers. Their industry has a need for lighter tires, which means steel cable will be a sought-after material for automotive fabrication. These steel cable filaments will be used in application for heavy equipment tires, cargo truck tires, conveyor belts, rubber framework and light truck tires.

As the famed architect Walter Grophius said, “New synthetic substances—steel, concrete, glass—are actively superseding the traditional raw materials of construction.” Even in modern days, fabrication and manufacturing industries are constantly finding news ways to use to use familiar, synthetic materials.

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Hercules SLR is part of the Hercules Group of Companies which offers a unique portfolio of businesses nationally with locations from coast to coast. Our companies provide an extensive coverage of products and services that support the success of a wide range of business sectors across Canada including the energy, oil & gas, manufacturing, construction, aerospace, infrastructure, utilities, oil and gas, mining and marine industries.

Hercules Group of Companies is comprised of: Hercules SLRHercules Machining & Millwright ServicesSpartan Industrial MarineStellar Industrial Sales and Wire Rope Atlantic.

A Brief History of Elevator Wire Ropes

The humble hoisting rope occupies a unique place in the history of vertical transportation. A simple hemp rope lies at the center of one of the best-known elevator stories — Elisha Graves Otis’ demonstration of his Improved Safety Device at the 1854 Crystal Palace in New York City.

Currently, a sophisticated carbon nanotube “rope” is the primary innovation driving the conceptual (and possibly literal) development of the proposed “space elevator”. However, the wire rope retains pride-of-place in elevator history as the longest-serving suspension means. It is the subject of numerous 19th-century articles that questioned its safety, and has been featured in countless contemporary books, movies and TV programs that predicate disaster on its failure. Today, we look at the introduction of wire elevator ropes in the 19th century and its development into the 20th century.

The invention of wire rope more-or-less paralleled the invention of the passenger elevator, and, by the 1870s, wire rope had become the rope of choice for elevator use. Since they were new, both the elevator and wire rope faced similar challenges regarding safety concerns. The older hemp hoisting rope had a long history of use, and its strengths and weaknesses were well known. However, a rope made of wire was an entirely different matter. This difference was effectively summarized in the June 22, 1878, issue of American Architect and Building News, which included a brief article on elevator ropes. The article expressed the primary concern in its opening sentence:

“The sudden introduction in our large cities of elevators, most of which are hung by wire ropes, has led people to wonder what will happen when they have had a year’s wear, and why there should not, after a while, be a breaking of ropes, and consequent accidents all over the country.”

The key concern centered on the endurance of wire rope and its reaction to constant and repeated bending as it passed around winding drums and over sheaves. One of the aforementioned article’s key assumptions was that “everybody knows, at least, that reiterated bending weakens wire, whether it be by granulation or by the constant extension of its fibers.” The challenge was, in spite of “knowing” that this action occurred, there was no easy way to judge when a rope was no longer safe for use.

The ICS author also addressed rope replacement, noting that “particular attention must be given to the fastenings.” The chief recommendation was to “carefully reproduce the joint as it was originally made” by the elevator manufacturer. A typical shackle used by Otis Elevator is described below in figure 1.

Figure 1: “Otis Elevator Co. Shackle,” ICS Reference Library (1902).

It consists of a split rod, the two legs A, A of which are bulged out and provided with noses at the ends. A collar B straddles the legs and eventually abuts against the noses. The rope is brought through the collar, bent over a thimble C, and passed back again through the collar, after which the free end is fastened by wrapping with wire. The wrapped end of the sections that address elevator ropes serves as a reminder that different elevator systems required different types of rope:

Chapter 1: Standard Methods and Facilities for Testing Wire Ropes
Chapter 2: Materials Composing Wire Rope and Their Properties
Chapter 3: Standard Types of Wire Rope Construction
Chapter 4: Variety of Uses of Wire Rope
Chapter 5: Mechanical Theory of Wire Rope
Chapter 6: Practical Hints and Suggestions
Chapter 7: Instructions on Ordering Wire Rope
Chapter 8: Typical Applications of Wire Rope in Practice

“When ordering rope for elevators, state whether hoisting, counterweight, or hand or valve or safety rope is wanted, also whether right or left lay is desired. The ropes used for these purposes are different and are not interchangeable.”

The diversity of elevator ropes was reflected in the design of American Steel & Wire’s standard hoisting rope, which was produced in six grades or strengths: Iron, Mild Steel, Crucible Cast Steel, Extra Strong Crucible Cast Steel, Plow Steel and Monitor Plow Steel. The company’s standard iron rope was primarily designed for use on drum machines and was “used for elevator hoisting where the strength is sufficient” (Figure 2). It was also described as “almost universally employed for counterweight ropes, except on traction elevators.” Their Mild Steel Elevator Hoisting Rope was designed “especially for traction elevators in tall buildings where, on account of [the] usual quick starting and stopping, a stronger and lighter rope is required.” Shipper or control ropes (also called tiller or hand ropes) differed from standard ropes in that they were composed of six strands of 42 wires each, which were wrapped around seven hemp cores (Figure 3).

wire rope figure 3 and 4

Figure 5: “Side Plunger Hydraulic Elevator,” American Wire Rope: Catalog & Handbook, American Steel & Wire (1913).

wire rope fig 5
Figure 5

In addition to providing detailed information on a wide variety of wire ropes, the catalog included schematic drawings that illustrated their proper application. These included 17 elevator-related drawings that depicted direct-, side- and horizontal-plunger hydraulic elevators; geared and traction electric elevators; and electric and belt-driven worm-geared elevators. The drawings’ emphasis on the application of wire ropes makes them a unique resource. Two versions of direct-plunger elevators were depicted — one with a shipper rope and one with an in-car controller — and the presence of two elevation drawings for each system permits a thorough understanding of these elevators (Figure 4). The same level of detail was provided for side-plunger hydraulic elevators (manufactured by Otis) and horizontal-plunger hydraulic systems (Figures 5 and 6).

Figure 6: “Horizontal Hydraulic Elevator,” American Wire Rope: Catalog & Handbook, American Steel & Wire (1913)

Figure 5
Figure 6

The electric elevator drawings are of particular interest, because, in 1913, they represented the newest systems on the market. The electric drum machine featured an interesting array of sheaves for the car and counterweight ropes, while the worm-gear machine employed a winding drum located near the midpoint of the shaft (Figures 7 and 8). The traction elevator drawing effectively illustrated its inherent simplicity and the potential of this new design (Figure 9).

The variety of elevator types illustrated in American Steel & Wire’s catalog represented the diversity of elevator systems prevalent in the early 20th century, as well as the importance of wire rope to their operation. Part Two of this article will follow this story through the 1930s, which encompasses the continued development of the traction elevator and the writing of the first elevator safety codes.

Figure 7: “Electric Drum Machine,” American Wire Rope: Catalog & Handbook, American Steel & Wire (1913).

Figure 7

Figure 8: “Worm Gear Electric Elevator,” American Wire Rope: Catalog & Handbook, American Steel & Wire (1913).

figure 8

Figure 9: “Traction Elevator,” American Wire Rope: Catalog & Handbook, American Steel & Wire (1913).

Figure 9

Original article can be found here at Elevator World Inc. 

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Hercules SLR is part of the Hercules Group of Companies which offers a unique portfolio of businesses nationally with locations from coast to coast. Our companies provide an extensive coverage of products and services that support the success of a wide range of business sectors across Canada including the energy, oil & gas, manufacturing, construction, aerospace, infrastructure, utilities, oil and gas, mining and marine industries.

Hercules Group of Companies is comprised of: Hercules SLRHercules Machining & Millwright ServicesSpartan Industrial MarineStellar Industrial Sales and Wire Rope Atlantic.

 

 

Rigging Hardware We Love: Crosby® 4-50 clip applications

crosby-clip-wire-rope-application-rigging-hardware

Rigging hardware is essential to our daily jobs—today, the spotlight is on the G-450 (Red-U-Bolt®) and SS-450 (316 Stainless Steel) Crosby clips. Read on to discover application tips and specifications for the 450 Crosby clips.

Efficiency Ratings

Efficiency ratings for wire rope end terminations are based upon the minimum breaking force of wire rope. The efficiency rating of a properly prepared loop or thimble-eye termination for clip sizes 1/8” through 7/8” is 80%, and for sizes 1” through 3-1/2” is 90%.

Number of Clips

The number of clips shown (see Table 1) is based upon using RRL or RLL wire rope, 6 x 19 or 6 x 36 Class, FC or IWRC; IPS or XIP, XXIP. If Seale construction or similar large outer wire type construction in the 6 x 19 Class is to be used for sizes 1 inch and larger, add one additional clip. If a pulley (sheave) is used for turning back the wire rope, add one additional clip.

The number of clips shown also applies to rotation-resistant RRL wire rope, 8 x 19 Class, IPS, XIP, XXIP sizes 1-1/2 inch and smaller; and to rotation-resistant RRL wire rope, 19 x 7 Class, IPS, XIP, XXIP sizes 1-3/4 inch and smaller. For other classes of wire rope not mentioned above, we recommend contacting Crosby Engineering to ensure the desired efficiency rating.

Elevator Application

For elevator, personnel hoist, and scaffold applications, refer to ANSI A17.1 and ANSI A10.4. These standards do not recommend U-Bolt style wire rope clip terminations. The style wire rope termination used for any application is the obligation of the user.

Applications: Crosby Clips

Refer to table 1 to follow instructions below:

crosby-ubolt-applications-specs

1. 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—live end rests in saddle (Never saddle a dead horse!). Use torque wrench to tighten nuts evenly, alternate from one nut to the other until reaching the recommended torque. (See Figure 1) wire-rope-crosby-clip-applications2. When two Crosby clips are required, apply the second clip as near the loop or thimble as possible. Use torque wrench to 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. (See Figure 2) wire-rope-crosby-clip-applications

3. When three or more Crosby clips are required, space additional clips equally between first two – take up rope slack – use torque wrench to tighten nuts on each U-Bolt evenly, alternating from one nut to the other until reaching recommended torque. (See Figure 3)

wire-rope-crosby-clip-applications4. If a pulley (sheave) is used in place of a thimble, add one additional clip. Crosby clip spacing should be as shown. (See Figure 4)

5. Wire Rope Splicing Procedures: The preferred method of splicing two wire ropes together is to use inter-locking turnback eyes with thimbles, with the recommended number of Crosby clips on each eye (See Figure 5). An alternate method is to use twice the number of clips as used for a turnback termination. The rope ends are placed parallel to each other, overlapping by twice the turnback amount shown in the application instructions. The minimum number of clips should be installed on each dead end (See Figure 6). Spacing, installation torque, and other instructions still apply.

wire-rope-splice-crosby-clip-application6. Important: Apply first load to test the assembly. This load should be of equal or greater weight than loads expected in use. Next, check and use torque wrench to retighten nuts to recommended torque. In accordance with good rigging and maintenance practices, the wire rope end termination should be inspected periodically for wear, abuse, and general adequacy.

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Hercules SLR is part of the Hercules Group of Companies which offers a unique portfolio of businesses nationally with locations from coast to coast. Our companies provide an extensive coverage of products and services that support the success of a wide range of business sectors across Canada including the energy, oil & gas, manufacturing, construction, aerospace, infrastructure, utilities, oil and gas, mining and marine industries.

Hercules Group of Companies is comprised of: Hercules SLRHercules Machining & Millwright ServicesSpartan Industrial MarineStellar Industrial Sales and Wire Rope Atlantic.

Wire Rope: A Manufacturing & Transportation Pioneer

Wire-Rope-Pioneer
Early Life

Andrew Smith Hallidie was born Andrew Smith, later adopting the name Hallidie in honour of his uncle, Sir Andrew Hallidie. His birthplace is variously quoted as London in the United Kingdom. His father, Andrew Smith (a prolific inventor in his own right, responsible for inventing the first box door spring, a floor cramp and had an early patent for wire rope) had been born in Fleming, Dumfrieshire, Scotland, in 1798, and his mother, Julia Johnstone Smith, was from Lockerbie, Dumfriesshire.

Andrew_Smith_Hallidie
Andrew Smith Hallidie

The younger Smith was initially apprenticed to a machine shop and drawing office. In 1852 he and his father set sail for California, where the senior Mr. Smith had an interest in some gold mines in Mariposa County. The mines proved disappointing, and he returned to England in 1853. Andrew Smith Junior, however, remained in California, and became a gold miner whilst also working as a blacksmith, surveyor and builder of bridges.

Inventions

In 1855, young Hallidie built a wire suspension bridge and aqueduct 220 feet long at Horse Shoe Bar on the Middle Fork of the American River. During 1856, whilst working on the construction of a flume at a mine at American Bar, the now, Andrew Smith Hallidie was consulted over the rapid rate of wear on the ropes used to lower cars of rock from the mine to the mill. These ropes wore out in 75 days—unsatisfied with this, Hallidie manufactured rope for the project consisting of three spliced pieces one-eighth of an inch thick, 1200 feet long. These lasted for two years—a vast improvement from the previous 75 day standard.

Hallide invented the Hallidie Ropeway, a form of aerial tramway used for transporting ore and other material across mountainous districts in the west, which he successfully installed in a number of locations, and later patented. After a few years of drifting from camp to camp working claims, narrowly avoiding disasters both natural and man-made, and briefly running a restaurant at Michigan Bluff in the Mother Lode, he abandoned mining in 1857 and returned to San Francisco. Under the name of A. S. Hallidie & Co., he commenced the manufacture of wire rope in a building at Mason and Chestnut Streets, using the machinery from American Bar.

In addition to aerial tramways, his rope was used to build suspension bridges across creeks and rivers throughout northern California. He was often away from the City on his bridge projects until in 1865 he returned to San Francisco and focused his energies entirely on manufacturing and perfecting wire rope. The discovery of the Comstock Lode silver mines in Nevada increased the demand for wire rope.

The city became a major industrial center for mining operations in the 1860s and Hallidie prospered, becoming a leading entrepreneur, US citizen, husband to Martha Elizabeth Woods, and in 1868 President of the prestigious Mechanic’s Institute.

Hallidie’s ‘Endless Wire Ropeway’—Precursor to Cable Cars

It was about this time that Hallidie began to implement a scheme for urban transportation he had been considered for some time, based upon his use of wire rope for the aerial tramways. He worked on improving the tensile strength and flexibility of his wire to develop an “endless” wire rope that could be would around large pulleys, which could then provide continuous underground propulsion for a car that could be attached or released at will from the cable. Hallide took out a patent Endless Wire Rope Patentfor this “Endless Wire Ropeway” and for years it dominated the construction of tramway at mines throughout the West. However, it was the implementation of his Endless Wire Ropeway for moving streetcars in San Francisco that brought him lasting fame and a place in the history books.

It is here accounts differ as to exactly how involved Hallidie was in the inception of the first cable car at Clay Street Hill Railway. One version, has him taking over the promotion of the line when the original promoter, Benjamin Brooks, failed to raise the necessary capital.

In another version, Hallidie was the instigator, inspired by a desire to reduce the suffering incurred by the horses that hauled streetcars up Jackson Street, from Kearny to Stockton Street.

There is also doubt as to when exactly the first run of the cable car occurred. The franchise required the first run no later than August 1, 1873, however at least one source reports that the run took place a day late, on August 2, but that the city chose not to void the franchise. Some accounts say that the first gripman hired by Hallidie looked down the steep hill from Jones and refused to operate the car, so Hallidie took the grip himself and ran the car down the hill and up again without any problems.

The named engineer of the Clay Street line was William Eppelsheimer. Given Hallidie’s previous experience of cables and cable haulage systems, it seems likely that he contributed to the design of the system.

wire rope cable car

The Clay Street line started regular service on September 1, 1873, and was a financial success. In addition, Hallidie’s patents on the cable car design were stringently enforced on cable car promoters around the world and made him a rich man.

A. S. Hallidie & Co. became the California Wire Works in 1883 with Hallidie as president. In 1895, it was sold to Washburn and Moen Co., the oldest manufacturers of wire in the United States (established in 1831).

Hallidie died on April 24, 1900 at the age of 65 of heart disease at his San Francisco residence, but his name lives on. In San Francisco, Hallidie Plaza (near the Powell and Market Street cable car turntable) and the Hallidie Building (an office building in the city’s Financial District) are named after him.

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Hercules SLR is part of the Hercules Group of Companies which offers a unique portfolio of businesses nationally with locations from coast to coast. Our companies provide an extensive coverage of products and services that support the success of a wide range of business sectors across Canada including the energy, oil & gas, manufacturing, construction, aerospace, infrastructure, utilities, oil and gas, mining and marine industries.

Hercules Group of Companies is comprised of: Hercules SLRHercules Machining & Millwright ServicesSpartan Industrial MarineStellar Industrial Sales and Wire Rope Atlantic.

 

Wire Rope Slings – Care and Maintenance

Wire-Rope-Sling

Terry Young, president of Construction Safety Experts, in the US, discusses identification, inspection and removal criteria for wire rope slings. The ASMEB30.9-2006 Standard requires wire rope slings to show the name or trademark of the manufacturer, diameter or size, number of legs, if more than one, and the rated loads for the types of hitches used and the angle upon which it is based.

The initial identification is done by the manufacturer and should be maintained by the user so as to be legible during the life of the sling. Replacement of wire rope slings identification should be considered as a repair and is required to be performed by the manufacturer or a qualified person. It must be marked to identify the repairing agency.

Wire rope sling 2

Additional proof testing is not required when replacing sling identification. An initial inspection should be performed prior to using new, altered, modified or repaired wire rope slings. It should be conducted by a designated person to verify compliance with applicable ASME 30.9-2006 standards.

A frequent visual inspection for damage must be performed by the user or designated person each day or shift the sling is used. The best safety practice is to inspect the wire rope before each use, task or lift.

Any condition meeting the ASME 30.9 – 2006 removal criteria or other condition that may result in a hazard must result in the sling being removed from service. The sling should then not be returned to service until approved by a qualified person. Written records are not required for frequent inspections.

A periodic inspection is to be conducted at intervals, not exceeding one year. This requires a complete inspection for damage to the sling by a designated person. The inspection should be conducted on the entire length, including splices, end attachments and fittings.

The frequency of periodic inspections should be based on frequency of use, severity of service conditions, nature of lifts being made and experience gained from the service life of slings used in similar circumstances or conditions.

Guidelines for the time intervals are

  • Normal service – yearly
  • Severe service – monthly to quarterly
  • Special service – as recommended by a qualified person or manufacturer
  • A written record shall be made and maintained of the most recent periodic inspection

Removal criteria

A wire rope sling shall be removed from service if conditions such as the following are present.

  • Missing or illegible sling identification
  • Broken wires
  • For strand- laid and single-part slings, 10 randomly broken wires in one rope lay, or five broken wires in one strand in one lay.
  • For cable-laid slings, 20 broken wires per lay.
  • For six- part braided slings 20 broken wires per braid.
  • For eight-part braided slings 40 broken wires per braid.
  • Severe localized abrasion or scraping
  • Kinking, crushing, birdcaging or any other damage resulting in damage to the rope structure
  • Evidence of heat damage
  • End attachments that are cracked, deformed or worn to the extent that the strength of the sling is substantially affected
  • Severe corrosion of the rope, end attachments or fittings.
  • Other conditions including visible damage that may cause doubt to the continued use of the sling

Hook removal criteria is listed in the ASME B30.10 Standard. Rigging hardware removal criteria is listed in the ASME B30.26 Standard.

Read original article here at International Cranes and Specialized Transport

For all your rigging repairs, inspections and services, call Hercules! Our inspectors are trained to the highest standard and are LEEA registered.

Hercules SLR is part of the Hercules Group of Companies which offers a unique portfolio of businesses nationally with locations from coast to coast. Our companies provide an extensive coverage of products and services that support the success of a wide range of business sectors across Canada including the energy, oil & gas, manufacturing, construction, aerospace, infrastructure, utilities, oil and gas, mining and marine industries.

Hercules Group of Companies is comprised of: Hercules SLRHercules Machining & Millwright ServicesSpartan Industrial MarineStellar Industrial Sales and Wire Rope Atlantic.

We have the ability to provide any solution your business or project will need. Call us today for more information. 1-877-461-4876. Don’t forget to follow us on Twitter LinkedIn and Facebook for more news and upcoming events.

Steel Wire Rope – How, Where, What and Why

steel wire rope

Steel wire rope is several strands of metal wire twisted into a helix forming a composite “rope”, in a pattern known as “laid rope”. Larger diameter wire rope consists of multiple strands of such laid rope in a pattern known as “cable laid”.

In stricter senses the term “steel wire rope” refers to diameter larger than 3/8 inch (9.52 mm), with smaller gauges designated cable or cords. Initially wrought iron wires were used, but today steel is the main material used for wire ropes.

Historically, steel wire rope evolved from wrought iron chains, which had a record of mechanical failure. While Fraying_steel_wire_ropeflaws in chain links or solid steel bars can lead to catastrophic failure, flaws in the wires making up a steel cable are less critical as the other wires easily take up the load. While friction between the individual wires and strands causes wear over the life of the rope, it also helps to compensate for minor failures in the short run.

Steel wire ropes were developed starting with mining hoist applications in the 1830s. Wire ropes are used dynamically for lifting and hoisting in cranes and elevators, and for transmission of mechanical power. Wire rope is also used to transmit force in mechanisms, such as a Bowden cable or the control surfaces of an airplane connected to levers and pedals in the cockpit. Only aircraft cables have WSC (wire strand core). Also, aircraft cables are available in smaller diameters than steel wire rope. For example, aircraft cables are available in 3/64 in. diameter while most wire ropes begin at a 1/4 in. diameter. Static wire ropes are used to support structures such as suspension bridges or as guy wires to support towers. An aerial tramway relies on wire rope to support and move cargo overhead.

History

Modern steel wire rope was invented by the German mining engineer Wilhelm Albert in the years between 1831 and 1834 for use in mining in the Harz Mountains in Clausthal, Lower Saxony, Germany. It was quickly accepted because it proved superior to ropes made of hemp or to metal chains, such as had been used before.

Wilhelm Albert’s first ropes consisted of three strands consisting of four wires each. In 1840, Scotsman Robert Stirling Newall improved the process further. In America wire rope was manufactured by John A. Roebling, starting in 1841 and forming the basis for his success in suspension bridge building. Roebling introduced a number of innovations in the design, materials and manufacture of wire rope. Ever with an ear to technology developments in mining and railroading, Josiah White and Erskine Hazard, principal owners[9] of the Lehigh Coal & Navigation Company (LC&N Co.) — as they had with the first blast furnaces in the Lehigh Valley — built a Wire Rope factory in Mauch Chunk, Pennsylvania in 1848, which provided lift cables for the Ashley Planes project, then the back track planes of the Summit Hill & Mauch Chunk Railroad, improving its attractiveness as a premier tourism destination, and vastly improving the throughput of the coal capacity since return of cars dropped from nearly four hours to less than 20 minutes. The decades were witness to a burgeoning increase in deep shaft mining in both Europe and North America as surface mineral deposits were exhausted and miners had to chase layers along inclined layers. The era was early in railroad development and steam engines lacked sufficient tractive effort to climb steep slopes, so incline plane railways were common. This pushed development of cable hoists rapidly in the United States as surface deposits in the Anthracite Coal Region north and south dove deeper every year, and even the rich deposits in the Panther Creek Valley required LC&N Co. to drive their first shafts into lower slopes beginning Lansford and its Schuylkill County twin-town Coaldale.

The German engineering firm of Adolf Bleichert & Co. was founded in 1874 and began to build bicable aerial tramways for mining in the Ruhr Valley. With important patents, and dozens of working systems in Europe, Bleichert dominated the global industry, later licensing its designs and manufacturing techniques to Trenton Iron Works, New Jersey, USA which built systems across America. Adolf Bleichert & Co. went on to build hundreds of aerial tramways around the world: from Alaska to Argentina, Australia and Spitsbergen. The Bleichert company also built hundreds of aerial tramways for both the Imperial German Army and the Wehrmacht.

In the last half of the 19th century, steel wire rope systems were used as a means of transmitting mechanical power including for the new cable cars. Wire rope systems cost one-tenth as much and had lower friction losses than line shafts. Because of these advantages, wire rope systems were used to transmit power for a distance of a few miles or kilometers.

Safety

The steel wire ropes are stressed by fluctuating forces, by wear, by corrosion and in seldom cases by extreme forces. The rope life is finite and the safety is only ensured by inspection for the detection of wire breaks on a reference rope length, of cross-section loss, as well as other failures so that the wire rope can be replaced before a dangerous situation occurs. Installations should be designed to facilitate the inspection of the wire ropes.

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