Tag: rigging

Are Your Shackles Safe for Overhead Lifting?

Are Your Shackles Safe for Overhead Lifting?

lifting shackles
Chain Style Shackle
lifting shackles
Anchor Style Shackle

When determining the best shackle for your lifting application, there are many options to choose from. Shackles are typically available in two styles: chain style and anchor style.

Chain shackles are best-suited for straight line, single connection pulls because of their U-shape. Anchor or bow shackles have a more generous loop. This allows them to be side loaded or used for multiple connections.

Whether you use chain or anchor shackles, there are three types of pins that are used to secure a shackle, each with their own benefits and limitations.

lifting shackles
Screw pin shackle
lifting shackles
Bolt, nut and cotter shackle
lifting shackles
Round pin shackle

 

 

Screw Pin Lifting Shackles

Screw Pin Shackles allow for quick and easy removal of the screw pin, which makes this style ideal for applications where the shackle is removed frequently. While the threaded pin can resist axial forces, it should not be cyclically loaded. Additionally, it is unreliable and vulnerable to backing out in applications where the pin is subjected to a torque or twisting action. In some applications, it is recommended to “mouse” the screw pin to prevent it from unscrewing. This type of shackle is suitable for overhead lifting.

Bolt, Nut & Cotter Lifting Shackles

Of all shackle types, bolt, nut, and cotter shackles provide the most secure pin arrangement, resisting axial and torsional loading. This type of shackle should be used in semi-permanent applications where the pin is removed infrequently. Bolt, nut, and cotter shackles are suitable for overhead lifting.

Round Pin Lifting Shackles

Round Pin Shackles allow for easy removal by simply removing the cotter that holds the pin in place. These shackles perform well where the pin is subjected to a torque or twisting action. They are not recommended for use where the pin is subject to an axial load. Round pin shackles are not suitable for overhead lifting.

For more information on shackles, check out our safety webinar on the Proper Use of Shackles or our other blog articles on shackles.

What is a Ramshorn Hook?

What is a Ramshorn Hook?

ramshorn hooks
Photo courtesy of @cranenation via Instagram

A Ramshorn hook is a shank hook with two throat openings, sometimes called sister hooks, double hooks or twin hooks. They are used in applications with shipyard cranes and container cranes. Ramshorn hooks can be used on any type of crane block.

Why Use a Ramshorn (Double) Hook?

Ramshorn hooks offer many benefits to the user. Not only do they allow for better rigging options due to the wider profile and double throat combination, they also provide better load distribution when using multiple slings in a rigging application.

Featuring an additional throat opening, Ramshorn hooks prevent slings from bunching up as they more frequently do with single hooks. This second throat also helps to prevent sling damage when under load. Featuring a wider hook profile, as compared to single hooks, Ramshorn hooks allow for more stable load control when properly rigged. The wider profile also provides better load distribution and allows for more controlled lifts.

Compared to single hooks, Ramshorn hooks commonly have a smaller frame with a much higher capacity, helping to reduce the weight of the overall crane lifting gear.

Not all Ramshorn Hooks Are Created Equal.

Ramshorn Hooks

There are two types of Ramshorn hooks: the Ramshorn Form A hook, which has a solid lower hook design, and the Ramshorn Form B hook. Columbus McKinnon offers the Form B version because of its versatility. This hook provides all the advantages as mentioned above with the addition of a hole in the lower hook to attach rigging hardware. This feature gives the user the option to change their double hook into a sling hook if so desired.

All Ramshorn hooks are manufactured to DIN 15402 standards. Just like our single hooks, these double hooks can be furnished in various configurations including unmachined, machined, and machined with nuts for full suspensions.

In 2015, Columbus McKinnon acquired Stahlhammer Bommern GmbH (STB), the leading manufacturer of heavy-load single and ramshorn hooks in Europe. Now available in North America, our offering includes a comprehensive line of CM Heavy-Duty Crane Hooks in both single- and double-hook configurations.

Download our Heavy Duty Crane Hook brochure.

In-Depth Alloy Chain Sling Inspection Part 5: OSHA Chain Sling Inspection

In-Depth Alloy Chain Sling Inspection Part 5: OSHA Chain Sling Inspection

This article is Part 5 of a 5-part blog series that will cover what professional riggers should consider when performing an in-depth alloy chain sling inspection. Today, we’ll discuss OSHA chain sling inspection regulations and guidelines.

Since first published on July 27, 1975, the OSHA Chain Sling Inspection section has undergone very few changes. These regulations have and continue to serve as a comprehensive guide for those responsible for chain sling inspection.

Chain SlingSpecifically, the applicable sections of the Code of Federal Regulations (29 CFR 1910.184) include:

1910.184(d) Inspections
Each day before being used, the sling and all fastenings and attachments shall be inspected for damage or defects by a competent person designated by the employer. Additional inspections shall be performed during sling use, where service conditions warrant. Damaged or defective slings shall be immediately removed from service.

1910.184(e) Alloy steel chain slings

1910.184 (e)(1) Sling identification
Alloy steel chain slings shall have permanently affixed durable identification stating size, grade, rated capacity, and reach.

1910.184(e)(2) Attachments

  • 1910.184(e)(2)(i)
    Hooks, rings, oblong links, pear shaped links, welded or mechanical coupling links or other attachments shall have a rated capacity at least equal to that of the alloy steel chain with which they are used or the sling shall not be used in excess of the rated capacity of the weakest component.
  • 1910.184(e)(2)(ii)
    Makeshift links or fasteners formed from bolts or rods, or other such attachments, shall not be used.

1910.184(e)(3) Inspections

  • 1910.184(e)(3)(i)
    In addition to the inspection required by paragraph (d) of this section, a thorough periodic inspection of alloy steel chain slings in use shall be made on a regular basis, to be determined on the basis of (A) frequency of sling use; (B) severity of service conditions; (C) nature of lifts being made; and (D) experience gained on the service life of slings used in similar circumstances. Such inspections shall in no event be at intervals greater than once every 12 months.
  • 1910.184(e)(3)(ii)
    The employer shall make and maintain a record of the most recent month in which each alloy steel chain sling was thoroughly inspected, and shall make such record available for examination.
  • 1910.184(e)(3)(iii)
    The thorough inspection of alloy steel chain slings shall be performed by a competent person designated by the employer, and shall include a thorough inspection for wear, defective welds, deformation and increase in length. Where such defects or deterioration are present, the sling shall be immediately removed from service.

Please note that while the requirements under (d) for daily inspections are not explicit as to scope or maintenance of records, it is possible that individual OSHA inspectors may have different views on conformity. However, the minimum 12-month interval inspections required under (e) call for thorough inspection and written records. It is this thorough type of inspection that the procedures recommended in our Rigging Catalog and CMCO Training Classes are designed to satisfy.

Of course, the fundamentals are equally applicable to the more cursory daily inspections made by riggers, users or inspectors (individuals deemed a “competent person”) and will enable them to fulfill their responsibility efficiently.

For more information:

 

In-Depth Alloy Chain Sling Inspection Part 4: Stretch and Chain Elongation

In-Depth Alloy Chain Sling Inspection Part 4: Stretch and Chain Elongation

This article is Part 4 of a 5-part blog series that will cover what professional riggers should consider when performing an in-depth alloy chain sling inspection. Today, we’ll discuss stretch and chain elongation.

Stretched Links
Stretched Links

A visual link-by-link inspection is the best way to detect dangerously stretched alloy chain links. Reach should also be measured from the upper bearing point on the master link to the bearing point on the lower hook. The smallest sign of binding or loss of clearance at the juncture points of a link indicates a collapse in the links’ sides due to stretch. Any amount of stretch indicates overloading, and the chain should be removed from service.

Note that a significant degree of stretch in a few individual links may be hidden by the apparent acceptable length gauge of the overall chain. This highlights the importance of link-by-link inspection.

Alloy steel sling chain typically exhibits well over 20% elongation before rupture. The combination of elongation and high strength provides energy absorption capacity. However, high elongation or stretch, by itself, is not an adequate indicator of shock resistance or general chain quality and should not be relied upon by riggers to provide advance warning of serious overloading and impending failure. Overloading must be prevented before it happens by selection of the proper type and size of slings. Again, any amount of stretch is overloading and the chain should be removed from service.

There is no short-cut method that will disclose all types of chain damage. Safety can only be achieved through proper inspection procedures. There is no adequate substitute for careful link-by-link scrutiny.

Additional Resources:

In-Depth Alloy Chain Sling Inspection Part 1: Twisting & Bending
In-Depth Alloy Chain Sling Inspection Part 2: Nicks and Gouges
In-Depth Alloy Chain Sling Inspection Part 3: Wear & Corrosion

To learn more, view our Chain Sling Inspection Safety Webinar.
Want to get trained? Check out our Qualified Rigger 3 day Workshop.

In-Depth Alloy Chain Sling Inspection Part 3: Wear and Corrosion

In-Depth Alloy Chain Sling Inspection Part 3: Wear and Corrosion

This article is Part 3 of a 5-part blog series that will cover what professional riggers should consider when performing an in-depth alloy chain sling inspection. Today, we’ll discuss chain wear and corrosion.

chain wear
Figure 1: Inspection for interlink wear can be easily detected by collapsing the chain.

When used in rigorous material handling applications, chain can easily become worn or corroded. It is important to inspect chain for defects on a regular basis to avoid an unsafe lifting condition or even operator injury. When corrosion and wear occur, it results in a reduction of link cross-section which can lead to decreased strength of the chain.

Corrosion can occur anywhere chain comes in contact with harsh chemicals, water or when it is used in tough environments.

Wear can occur in any portion of a link that is subject to contact with another surface.

The natural shape of chain confines wear, for the most part, to only two areas. These are, in order of importance, (a) at the bearing points of interlink contact, and (b) on the outsides of the straight side barrels that may be scraped from dragging chains along hard surfaces or out from under loads.

Figure 1 illustrates the condition of interlink wear and shows how to inspect for it. Notice how easily such wear can be detected by collapsing the chain to separate each link from its neighbors. An operator or inspector can also check for corrosion using the same method.

When chain wear or corrosion is observed, the next step is to determine how severe the damage is and if the chain can still be safely used.

General surface corrosion can be removed by cleaning and oiling the chain. If pitting is observed after cleaning and oiling, remove from service. Next, the operator should take a caliper measurement across the worn section of chain and compare it to the minimum allowable dimension for that chain.

See the chart below for minimum section dimensions or chain wear allowances for Grade 80 and 100 Chain. If the chain does not meet these minimum dimensions, it should be removed from service and replaced.

chain wear

Stay tuned for our next part in this series where we’ll talk about Chain Inspection.

Additional Resources:

In-Depth Alloy Chain Sling Inspection Part 1: Twisting & Bending
In-Depth Alloy Chain Sling Inspection Part 2: Nicks and Gouges

To learn more, view our Chain Sling Inspection Safety Webinar.
Want to get trained? Check out our Qualified Rigger 3 day Workshop.

Understanding the Difference between Chain Grades and How They’re Used

Understanding the Difference between Chain Grades and How They’re Used

chain grades
Chain has been around for over a thousand years. It is one of the most versatile and reliable ways to lift, tension and tie down materials in a variety of applications. In the past, people would use any type of chain to lift something, tie down a load or tow a vehicle. Proper inspection, safety procedures and general standards of practice for chain were lacking.

In recent years, due to safety concerns and regulations, the industry has begun to differentiate between various materials and grades of chain and the specific applications they should be used for. ASTM (American Society of Testing & Materials), ASME (American Society of Mechanical Engineers) and OSHA (Occupational Safety & Health Administration) began to publish safety standards and regulations for the manufacturing, testing, use, inspection and repair of chain.

Chain Grades

One of the safety measures implemented was to place chain in Grades based on the ultimate breaking strength of that chain. This number is what we see today G30, G43, G70, G80 & G100 and the common chain grades. The number after each letter is N/mm2. For example, G80 means that the maximum stress on the chain at ultimate strength is 800 newtons per millimeter squared.

Working Load Limit (WLL) of Chain

The other safety measure was identifying which types of chain are appropriate and strong enough for overhead lifting. Anytime we move or lift a load it is dangerous. Moving a load along the ground has the advantage that the ground is supporting the load. We have to overcome the coefficient of friction to move the load. The chain’s working load limit does not have to match the weight of the load. It needs to be able to handle the tension applied, which is based on the surface that it is being moved over plus some fraction of the weight of the load. This can be calculated using formulas.

If we lift that same load off the ground, we now have to overcome gravity. The chain’s working load limit will have to be of sufficient strength to support the weight of the load plus any additional forces imposed by angles and hitch type(s) used.

Which Chain Grade Should Be Used for Which Type of Application?

Alloy Chain Grade 80 or Grade 100 should be used for overhead lifting. ASTM states that alloy chain shall be able to elongate a minimum of 20% before fracture (7.3.5). To ensure that alloy chain consistently meets this requirement, ASTM requires the use of certain alloying elements in the manufacturing of the steel for alloy steel chain. These alloys can vary from company to company, but some key requirements are specified by ASTM. The alloy properties also improve the wear and tear that the chain will experience.  Note that when chain is in use, no amount of stretch is allowed.

Carbon Grade 70 chain is a “heat treated” carbon steel chain that has no alloying elements added to the steel. This chain will elongate before breaking but does not have the properties needed for overhead lifting; therefore, Grade 70 chain is not intended for overhead lifting. This chain is designed for use as a tie down chain or lashing for transportation. Grade 70 chain has a gold chromate finish to help resist corrosion from continuous exposure to the elements and the rigors of highway use, such as road salts in the winter.

When any type of overhead lifting is required, use only alloy chain slings unless specified by the manufacturer.

The preferred chain for load securement is Grade 70, but any grade of chain can be used for tie downs or tensioning. You have to know your tensions in order to select the proper chain. Refer to load securement safety standards FMCSA (Federal Motor Carrier Safety Administration), CVSA (Commercial Vehicle Safety Alliance), WSTDA (Web Sling Tie down Association) or the state regulations for more information.

Training is key in knowing how to properly size and use any type of chain for any application. Learn more about Columbus McKinnon training programs.

Watch our Safety Webinar on Load Securement.

Free Safety Webinars to Resume in January 2015

Free Safety Webinars to Resume in January 2015

Each month, the Columbus McKinnon training team hosts a free online safety webinar. We will not be holding a webinar in December, but to keep you focused on safety during this holiday break, we had a little fun making a video featuring five important tips to get you through the season safely.

We hope to see you in January, when our monthly safety webinars return with
Hoist Chain Lubrication: Why is it so Important?Register now.

Need a stocking stuffer idea?
Order the complete set of Safety Webinars!
We’ve compiled all of our 2014 recorded webinars on one convenient USB thumb drive. As an added bonus, we have also included all of our 2013 Safety Webinars.

Order by Christmas and we’ll include a free CM Rigging Guide!

We would like to thank all of our past safety webinar attendees for their time and interest, with a special call out to our Safety All-Stars for 2014:

  • Standard Crane, the company who attended the most CMCO Safety Webinars
  • Patrick Cox of Westech Rigging Supply, the individual who attended the most CMCO Safety Webinars

Thanks for all of the great feedback we have received on our safety webinars this year. Stay tuned for more engaging content to help you work safer in 2015!

A Chain Sling Question from the Mining Industry

A Chain Sling Question from the Mining Industry

Chain Inspection photoHere is a question from Adam, a mobile crane operator working in the mining industry, who regards proper rigging equipment and practices as a major safety priority:

“We have a 1-inch GR80 chain sling, 30 feet in length that is around ten years old and in good condition, although there is inner link wear throughout the sling at its bearing points. The narrowest measurement in link diameter at any point was .945″, which is well away from removal criteria. No components in the sling show any evidence of a stretch condition, and the sling has not been subjected to overload to the best of our knowledge, though I cannot guarantee that.

“The reach of the sling is approximately four inches longer than its tag indicates. According to my calculations, this stretch is due to the contact wear in each link. The chain moves freely and there is no binding or restriction of movement. Is this legitimate? If so, does the tag need to be replaced or modified to indicate its current length? Our inspections have always been completed by a company assigned employee.”

Response from Peter Cooke, training manager:

Thank you for reaching out to us. For your reference, I have included a section on alloy rigging chain inspection from our Columbus McKinnon rigging catalog here. Be sure to do a link-by-link inspection and follow the rejection criteria from OSHA 1910.184 and ASME B30.9. Be sure there are no stretched links. Reference the “Allowable Chain Wear Allowance tables” from the manufacturer and ASME B30.9.

Not knowing your exact configuration, I will use a standard DOS 1-inch grade 80 x 30’ reach sling as an example. If we just isolated the chain (taking out the master link, coupling links and hooks) you have approximately 106 links of chain. If you determined the minimum thickness to be 0.945” at the bearing points, that is approx. 0.055” of wear from the nominal dimension. 1” grade 80 chain has a pitch length of approx. 3.07” (dimension from the top inner link radius to the lower inner link radius) Let’s assume that wear occurred at both ends of the chain link. The pitch length would increase by 0.11”. Over the entire chain length you could see an increase in reach of approx. 11.66” (0.11” x 106 = 11.66”)

As long as there are no stretched links or deformation this would be acceptable. There is no rejection criteria for reach other than stretch. Wear is not stretch.

There is also no statement in 1910.184 and ASME B30.9 to replace the tag in this event with the correct reach.

A good practice would be to retag the sling with the current reach. The new tag would be considered a repair so your company’s name or initials would have to be on the tag. A load test would not be required. Lastly, lubricating the chain is an excellent way to minimize wear.

Sling Selection & Working Load Limits: What You Need to Know

Sling Selection & Working Load Limits: What You Need to Know

Chain slings are a combination of chain, hooks, rings and other attachments used primarily for overhead lifting applications. Slingssling selection are often used in conjunction with cranes and other lifting devices and allow riggers to create custom configurations to lift loads depending on the needs of that specific application.

Standard chain sling configurations consist of chain branches that are affixed on one end to a master link or ring with some type of attachment. When building a sling, ASME, NACM and OSHA recommend that only alloy steel chain is used. Columbus McKinnon’s Herc-Alloy chain, available in Grades 80 and 100, is made of superior triple alloy steel and is a strong and durable option for building chain slings.

All chain slings should come with a metal identification tag that is affixed to the chain. The tag should include the following information: sling size, reach, working load limit, serial number, manufacturer name, grade of sling and number of branches.

Proper Chain Sling Selection

When choosing a chain sling there are a few things to consider:

  1. Weight and configuration of the load(s) to be lifted
  2. Type of chain sling required, according to weight and configuration
  3. Size of the body chain according to the working load limits. Be sure to take into consideration the effect of the required angle (see information below).
  4. Reach required to give the desired angle. This is measured from the upper bearing surface of the master link to the bearing surface of the lower attachment.
  5. The share of load on pick points and location of the center of gravity

What Determines a Sling’s Working Load Limit?

The working load limit indicates the maximum load that should be applied to the sling and should never be exceeded during use to ensure operator safety.
Sling working load limits are determined by the following:

  • Type of hitch
  • Material strength
  • Design factor
  • Diameter of curvature (D/d)
  • Angle of loading

The working load limit of a sling can also be affected by the conditions the sling is used in. For example, rapidly applying a load can produce dangerous overloading conditions. Also, the twisting and knotting of links or sling components can decrease a sling’s working load limit. Environmental conditions, such as elevated temperatures, can affect the working load limit of a sling as well.

Since slings are most often used at an angle, let’s review an example of how angle of loading affects a sling’s working load limit. In the diagram below, the percentages shown represent the maximum working load limit of the sling when used at the designated angle. In some instances the working load limit of the chain is reduced to 50%!

For example: One 3/8″ Grade 80 double sling used at 90˚ would have a working load limit of 2 times the working load of a 3/8″ Grade 80 single or 2 x 7, 100 lbs. = 14,200 lbs.

The same double sling used at 35º would have a maximum working load limit of 57% of 14,200 lbs. or .57 x 14,200 lbs. = 8,094 lbs.

sling selection

For another example of how the angle of use can affect the working load limit of a chain sling, check out this past blog post: What is the working load limit of a 2 legged chain sling?

Want to learn more? View our Safety Webinar on Chain Sling Inspection

The Low-down on Plate Clamp Inspection and Operation

The Low-down on Plate Clamp Inspection and Operation


Crane & Rigging Hot Line
recently published an article on plate clamp inspection and operation based on a presentation given by one of Columbus McKinnon’s corporate trainers, Chris Zgoda, at the ACRP Conference in San Antonio, TX.  Below are a few of the highlights:

Plate Clamp Operation
Plate clamps are most often used to lift and move steel plates from both horizontal and vertical positions. CM’s clamps operate through a self-actuating spring that engages when the clamp is attached to a plate. When using plate clamps, it is important that the load is close to the clamp’s working load limit – weighing no less than 20 percent of the clamp’s working load limit.

Inspecting a Plate Clamp
Lifting clamps are just like any other piece of machinery and therefore require frequent inspection and maintenance. Clamps should be inspected every one to four weeks, depending on frequency of use. Plate clamps should be degreased and cleaned regularly and should be lubricated as needed to ensure smooth operation. When inspecting clamps it is important to check the teeth, handle, shell plates and other components like bolts, nuts and chain.

To read the full article in Crane & Rigging Hot Line, click here.