What Are Links and Rings?
Links and rings are closed-loop devices that are designed to help with the assembly of a single or multi-leg sling. They're commonly used as the connection point for one, two, three, or four sling-leg configurations, especially ones that are made from chain or wire rope. Oblong master links, master rings, and leaf-shaped master links—collectively known as master links and rings—are often referred to as collector rings or collector links, since they can collect multiple sling legs into a single link. They're normally used in sling assemblies, but links and rings can also be used as a connection point between any two parts of a rigging assembly. You can use a link or ring to connect a shackle to a crane hook, a sling to a hook, or a link to a sling hook, for example.
The Different Types of Links and Rings
Now that you know what links and rings are, let’s go over some of the different types of links and rings and how they're used. There's a wide variety of different links and rings that you can use in an assembly, but the most popular types include:
- Oblong master links
- Master link sub-assemblies
- Pear-shaped links
- Master rings
- Coupling links
Let's go over each of these types a bit more in-depth.
Oblong Master Links
An oblong master link is an oblong permanently closed loop. It's normally used at the top of a multi-leg chain assembly or wire rope bridle and is the connection point that collects the legs making up the sling assembly. While an oblong master link is predominantly used as a connection point in a multi-leg sling, you can also use it as a connection point between rigging equipment and hardware. Its oblong shape makes it ideal for attaching crane hooks that have a large measurement from the bearing of the bowl to the bottom of the hook, also known as the hook saddle. It's not uncommon to use an oblong master link to connect a shackle to a crane hook, a hook to a shackle, and for other rigging assemblies.
Master Link Sub-Assemblies
A master link sub-assembly can be used as a replacement for a single master link in assemblies with more than two sling legs. It's not impossible to have three or four legs attached to a single master link, but doing so requires heavy, thick links that are harder to manage. A sub-assembly consists of two master coupling links that are attached to an oblong master link. Instead of attaching all four slings to a single master link, you can split them between the two sub-assembly links. A master link sub-assembly can reduce the size of the master link while maintaining a similar Working Load Limit (WLL) to the original link.
Pear-Shaped Master Link
A pear-shaped master link is similar in function to an oblong master link. It's used for multi-leg chain slings, wire rope bridles, and various rigging connection points. A pear-shaped master link has limited uses and should only be used to accommodate smaller sling shape assemblies with two or fewer legs. The unique shape of this link makes it ideal for use with narrow hooks. It's a tighter fit than an oblong master link, which eliminates side-to-side load movement on the surface of the hook.
A master ring is a circular, permanently closed ring that can be used with wire rope bridles, chain slings assemblies, and other rigging connection points. You can use a master ring to accommodate multi-leg assemblies, but an oblong master link will almost always work more efficiently. This is because the master ring's round shape makes it less ideal for connecting to crane hooks. You'll usually see master rings being used in fabrication or small machine shops, but rarely for use with larger equipment and assemblies.
A coupling link is a mechanical or welded part that's used to connect part of a chain to a master link or fitting. You can also use them to create a connection between master links, hooks, or other pieces of hardware. A welded coupling link is connected to the master link and then welded shut to form a connection. A mechanical coupling link consists of multiple parts, including a bushing, bolt, and spring. It's an attachment point that hinges at the center.
How Are Links and Rings Marked and Identified?
You can find manufacturer markings on every link, master link sub-assembly, and ring that you purchase. These marks indicate the name or trademark of the manufacturer, the size or rated load, and the grade, when it's required to identify a rated load.
When Not To Use Links and Rings
Most links and rings are relatively sturdy, but that doesn't mean they're completely immune to deterioration. Your links and rings will start to wear down over time, either due to age, excessive use, or other external factors. For safety reasons, you should remove your links and rings from service if they:
- Are missing identification or have illegible identification
- Have been affected by heat damage
- Show signs of excessive pitting, corrosion, nicks, or gouges
- Have load-bearing components that are bent, twisted, distorted, stretched, elongated, cracked, or broken
- Have unauthorized welding or modifications
- Show a ten-percent reduction of the original or catalog dimension at any point
- Have any type of visible damage that could compromise their durability
You can have your links and rings returned for service if these problems are addressed and approved by a qualified person.
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