- Erstellt: 22-10-21
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Are you planning your next overhead lifting project and need to specify the type of sling and rigging equipment you’ll be using? While it’s important to understand the best type of sling to use, it’s just as important to select the right type rigging hardware that will be connected to that sling. Choosing the right type of lifting hook that can be used will be determined by a number of different factors.
In this article, we’ll discuss the different type of G100 sling hooks that exist, including: eye hooks, clevis hooks, swivel hooks, hooks with latches, sorting hooks, foundry hooks, j-hooks, grab hooks, and barrel hooks.
At Mazzella, we offer all styles of lifting slings, rigging hardware, wire rope, overhead cranes and hoists, hoist parts, and engineered below-the-hook lifting devices. Our goal for this article is to help you select the right type of sling assembly for your future lifting and rigging needs.
If you’re looking for more information on the advantages/disadvantages between wire rope, chain, and synthetic slings, we also have an article on how to choose the best lifting sling for your application.
There are two main ways a lifting hook or G100 self-locking hooks can be attached to the sling—you can either use a hook with an eye at the top, or with a clevis at the top to make your connection to the sling. There are also hooks that have a bearing or bushing at the top that swivels. We’ll dive a little deeper into all three of these styles below:
On an eye hook, a chain or fittings are welded for a permanent connection to the sling. With an eye hook, you get far more flexibility in terms of movement and ergonomics to position the hook and attach it to the load. However, an eye hook is a permanent solution—if the throat of the hook becomes stretched, cracked, or bent during use, the whole sling would have to be failed out upon inspection and removed from service.
A clevis fastener is a fastener system consisting of a clevis and clevis pin. The clevis is a U-shaped piece that has holes at the end of prongs to accept the clevis pin. The clevis pin is similar to a bolt, but is only partially threaded or unthreaded with a cross-hole for a split pin. A clevis hook is a hook, with or without a snap lock, with a clevis and bolt or pin at the base. The clevis is used to fasten the hook to a bracket or chain.
Some rigging shops and end users who are not certified to weld alloy chain slings, utilize clevis hooks to make a mechanical connection to a chain sling. The advantage of a mechanical connection is that if a clevis hook becomes damaged due to stretch, bending, or cracking, it can easily be removed and replaced without scrapping the entire chain sling. If this occurs on a chain sling, this is considered a repair to the sling and must be proof-tested prior to the sling being put back into service.
Also, a clevis hook can pivot side to side for positioning when connecting to a load, but doesn’t have the same flexibility or freedom of movement that an eye hook does.
There are two types of swivel hooks and the user should be aware of the type of swivel hook that they’re using prior to lifting a load into the air:
Positioning Swivel Hook – This type of hook swivels to allow the rigger to properly align the hook during connection to the load. This type of hook is NOT designed to rotate while under load and is only to be used when you need to position the hook onto the pick point.
True Swivel Hook with Bearing – This type of swivel hook has a bearing inside that allows the hook to rotate freely under load. The top fitting swivels and pivots to allow the load to rotate to prevent twisting of the rigging.
When deciding on whether to use a hook latch or not, careful consideration must be given to the specific lifting application. The use of latches on hooks is a topic that is constantly up for debate in the lifting and rigging industries. While some people argue that hook latches are always required and should always be utilized, others argue that latches are not required.
Unfortunately, there are limited explanations or interpretations of when a latch on a hook must be utilized. With no clear industry-wide rules on whether a hook latch is required on a crane hook or a G100 grab hook, the decision is ultimately left up to the owner or end-user.
As an organization, Mazzella recommends that hook latches should be used. When we train our employees and inspectors on the use of hook latches, we take all of the following into consideration:
Any hook that is designed to have a latch, should have the latch installed
New slings are sold with the latch installed unless the customer requests no latch
If customers make an inquiry about the use of a latch on a hook, we may recommend for them to consider several OSHA standard interpretations, among them the following:
The Occupational Safety and Health Act of 1970 also contemplates that, in the absence of a specific OSHA standard addressing a hazard, employers are required, by the statute’s “General Duty Clause” (Section 5(a)(1)), to protect employees from serious recognized hazards. OSHA often considers the provisions of industry consensus standards, such as those published by the American National Standards Institute (ANSI) or the American Society of Mechanical Engineers (ASME), when evaluating whether a hazard is “recognized” and whether there is a feasible means of abating that hazard.
One such provision that OSHA would consider is Section 2-1.14.5, Hooks, of ASME B30.2- 2001, Overhead and Gantry Cranes: “Latch-equipped hooks shall be used unless the application makes the use of the latch impractical or unnecessary.”
Or the following OSHA standard interpretation may be referenced: The requirement for safety latches (AKA throat latches) is only specified in OSHA 1910.181(j)(2)(ii), which states that “Safety latch type hooks shall be used wherever possible.”
Or the following OSHA standard interpretation may be referenced: Whether OSHA requires a safety latch on a G80 self-locking hooks depends on the activity for which the sling is being used.
We advise that the end user must evaluate the work activity with regards to the safety of their employees. If the activity makes the use of the latch impractical, unnecessary, or more dangerous, then the end user may choose to eliminate the latch. It is also recommended that each lifting activity is considered independently as far as the use of a hook latch is concerned.
All hook manufacturers make products with or without latches. Some hooks are compatible with self-closing latch kits so that a latch can be added at the time of the sale or post-sale.
There are two types of hooks that rarely utilize a latch assembly due to the nature of the lift or the environment where the lift is being performed:
A sorting hook will never utilize a latch kit. They’re typically being utilized for lifts with tip loading or where a latch would limit the practical use when lifting plates and cylindrical loads (such as pipe) where full throat engagement is required.
A foundry hook rarely utilizes a latch kit because they’re often used in environments or applications where there is a clear danger for a worker to reach up to connect the load or remove the load from the hook.
The one disadvantage of a hook with a self-closing latch is that they have a much shorter life span than a positive latching hook. One thing to consider when buying a hook with a latch kit is to understand if it’s an imported or domestically-made product.
Imported rigging products are attractive because they’re often less expensive than a domestically-made product. However, if the latch breaks on an imported hook, it can be very difficult, or expensive, to find a replacement latch kit. You may even wipe out the initial cost-savings by having to buy a completely new hook because you can’t source the replacement latch kit.
For domestically-made hooks, you can contact the manufacturer or distributor directly and they can provide you with the exact replacement latch kit part # and get you a replacement kit at a fraction of the cost of a new hook.
A positive latching hook is a hook with a latch that is a more robust and engineered component of the hook. The advantage of a positive latching hook is that it’s nearly impossible to break the latch on these hooks and once it closes, it can’t open again until the load is released from the hook.
These types of hooks are close to standard on chain slings because they’re more robust and can handle heavier-duty environments and lifts where chain is the preferred sling medium.
Sorting hooks, also known as “lay out hooks” or “shake out hooks,” are used to sort or lay out products like flat plate, pipes, or other tube-shaped objects. They’re used in multi-leg sling assemblies for applications where the object or item will engage to the full depth of the throat of the hook.
Sorting hooks must be used at a 30° to 45° angle to get full engagement—if the load is not fully engaged with the throat opening, significant reduction to the Working Load Limit of the hook can occur.
Sorting hooks are one of the few types of hooks designed not to use a latch. The use of a latch would limit the practical use of the hook when lifting plates and cylindrical loads where full throat engagement of the hook is required.
A sorting hook is NOT the same as a pelican hook. Many customers mistakenly refer to a sorting hook as a “pelican hook.” However, pelican hooks are used in nautical and marine applications and are not rated to perform overhead lifts.
Foundry hooks are typically used on chain slings and are designed with a wide deep throat to fit trunnions and handles on molds or castings for foundry work.
Foundry hooks are most commonly designed to be used without a latch, because they’re often used in high-heat applications where there is a clear danger for a human to reach up to connect or remove the load from the hook.
Due to the environments they’re used in, foundry hooks are often used in applications where tip loading is necessary.
J-Hooks are most often used in industrial and manufacturing applications. They have a low-profile and slimmer design than traditional sling hooks, which allows them to be used with chains, hoists, and slings to efficiently move materials in applications where a sling hook, grab hook, or foundry hook would not be suitable.
J-Hooks are often used with eye bolts or an engineered lifting point on a load. A low-profile tip and throat can fit in much easier than a larger sling hook or foundry hook for a positive connection to the load.
J-Hooks are often custom-engineered for the specific application and are most commonly used without latches, but latch kits are available. The eye at the top of the hook can be configured in a variety of orientations depending on the application. “Style A” and “Style B” J-Hooks have an eye that’s parallel with the rest of the hook, while “Style C” J-Hooks have an eyelet that is perpendicular to the hook body.
Because J-Hooks have less material than standard G80 grab hooks, they have a lower Working Load Limit than most other types of hooks.
Grab hooks are designed with a special narrow throat used to “grab” and shorten or hold a length of chain used in tie-down applications and in load-rated lifting slings. The throat engages the chain between the links for quick non-slip handling. Grab hooks are manufactured to be used with a specific size and grade of chain. There are two types of grab hooks, so the end-user should understand what type of grab hook they’re using prior to lifting a load into the air:
Standard grab hook – Becoming less common, the “non-cradle” grab hook is most often seen in tie-down applications. When using a standard style grab hook, it is important to be aware of any reductions in working load limit (WLL) that the hook manufacturer may require based on usage configuration. When using a “standard” grab hook, most manufacturers require a reduction of 20% of the WLL.
Cradle grab hook – The “cradle style” is replacing the “non-cradle” or “standard” grab hook for most applications due to its improved support of the engaged chain link. This additional support of the engaged link often means there is no reduction of working load limit (WLL) when used as designed. Always follow manufacturer recommendations for all lifting products.
Barrel Hooks are used for lifting barrels or drums. They have a wide end point that goes under the lip of a barrel or drum and are used in conjunction with a multi-leg sling assembly. Typically used in conjunction with a pair of slings and are designed to be utilized at 30-45° angles.
When it comes down to it, the most important part of determining what type of hook to use for an overhead lift is to ask yourself, “how am I connecting to the load?” Will the load have eye bolts, swivel hoist rings, engineered lifting points, or will you be using shackles to connect the hook to?