Triplex Links

What are triplex links?

Triplex links are connecting and repair links used to join, shorten, or repair triplex roller chain. Triplex chain has three rows of rollers running side by side, giving much higher strength and power capacity than single-strand (simplex) or double-strand (duplex) chain. Because roller chain is supplied in lengths and needs to be joined into a continuous loop, connecting links are used to close the chain, while other links are used to adjust the chain length or replace damaged sections.

Triplex links are designed to match the pitch, roller size, and width of the triplex chain exactly, so the joined chain runs smoothly over triplex sprockets and carries its full load.

A typical triplex connecting link has:

• Outer plates - the side plates that hold the link together and connect to the inner links of the chain
• Pins - three-strand-width pins that pass through the chain, usually fixed into one outer plate
• Middle plates - plates between the strands that support the pins and keep the strands aligned
• Removable side plate - the loose plate fitted over the pin ends to close the link
• Fastener - a spring clip, split pins, or rivets that hold the removable plate in place

Triplex links are usually described by:

• Chain size - such as 06B-3, 08B-3, 10B-3, or 12B-3 for British Standard chain, or 40-3, 50-3, or 60-3 for ANSI chain. The 3 shows it is triplex
• Chain standard - British Standard (BS) or American Standard (ANSI)
• Pitch - the distance between the centres of adjacent pins, such as 3/8 inch, 1/2 inch, 5/8 inch, or 3/4 inch
• Link type - often identified by a number, such as Nr. 26 for a connecting link with a spring clip

For example, an 08B-3 Nr. 26 triplex connecting link joins 1/2 inch pitch British Standard triplex chain, and is secured with a spring clip.

Key features:

• Joins chain into a loop - closes triplex chain around the sprockets
• Matches the chain exactly - made to the same pitch, roller size, and width as the chain
• Quick fitting - spring clip links can be fitted and removed with simple tools
• Repairs damaged chain - replace worn or broken sections without replacing the whole chain
• Adjusts chain length - cranked links allow an odd number of links where needed
• Strong construction - made to carry heavy loads in triplex drives
• BS and ANSI sizes - to suit both British Standard and American Standard chains

In simple terms, triplex links are the connecting and repair links that join triplex roller chain into a strong, continuous loop.

Why are triplex links essential?

Triplex links are essential because every roller chain drive needs a reliable way to join the chain, and because chains sometimes need repairing or adjusting. Triplex chain is used on heavy-duty drives where failure would cause costly downtime, so using the correct, high-quality connecting link is vital. The wrong link, or one that is fitted incorrectly, can come apart, damage sprockets, and stop the machine.

Their main benefits are:

• Secure chain joining - closes the chain loop safely and reliably
• Quick installation - chains can be fitted and removed without special equipment
• Easy repairs - damaged links can be replaced quickly, reducing downtime
• Length adjustment - allows chains to be shortened or adjusted to suit the drive
• Full compatibility - matched to the chain for smooth running over sprockets
• Heavy-duty strength - suited to the high loads carried by triplex chain
• Cost-effective - repairing chain is often cheaper than replacing it

Triplex links are used across a wide range of industries and applications, including:

• Heavy industrial drives - high-power chain drives on industrial machinery
• Conveyors - heavy-duty conveyor drives
• Mining and quarrying - crushers, screens, and conveyors
• Agricultural machinery - heavy-duty drives on harvesters, mills, and processing equipment
• Steel, paper, and timber processing - high-load drive systems
• Pumps and compressors - heavy chain-driven equipment
• Construction and plant machinery - heavy-duty drives
• Maintenance and repair - replacing and adjusting chain on existing drives

The main types of triplex links

Triplex links are usually grouped by their design and the chain standard they suit.

By link type:

• Connecting links with spring clip - often referred to as Nr. 26 links. The removable side plate is held in place with a spring clip, allowing quick fitting and removal. Commonly used on smaller and medium triplex chains
• Connecting links with split pins - the removable side plate is held with split pins through the ends of the pins, often used on larger chain sizes
• Riveting connecting links - the pins are riveted over after fitting, giving a strong, permanent joint for high speeds and heavy loads
• Cranked links (offset links) - these allow a chain to have an odd number of links. Cranked links reduce chain strength, so they should only be used when necessary
• Double cranked links - two-pitch offset links that also allow odd link counts, giving a stronger option than a single cranked link
• Inner links - the roller links between connecting links, used for repairs

By chain standard:

• British Standard (BS) triplex links - suit European-style roller chains, such as 06B-3, 08B-3, 10B-3, 12B-3, and 16B-3
• ANSI triplex links - suit American-style roller chains, such as 40-3, 50-3, 60-3, and 80-3

British Standard and ANSI chains of the same pitch are not interchangeable, as their roller diameters, inner widths, and plate dimensions are different.

Common pitches:

• 3/8 inch - such as 06B-3 and ANSI 35-3
• 1/2 inch - such as 08B-3 and ANSI 40-3
• 5/8 inch - such as 10B-3 and ANSI 50-3
• 3/4 inch - such as 12B-3 and ANSI 60-3
• 1 inch - such as 16B-3 and ANSI 80-3

How to choose the right triplex links?

Choosing the right triplex link means matching it exactly to the chain. Work through these points in order:

• Chain standard - check whether the chain is British Standard or ANSI. This is often stamped on the chain plates
• Chain size - match the chain size, such as 08B-3 or 40-3
• Number of strands - make sure the link is triplex, to match a three-strand chain
• Pitch - check the pitch by measuring the distance between the centres of adjacent pins
• Link type - choose a connecting link to join the chain, a cranked link if you need an odd number of links, or inner links for repairs
• Fastening method - choose spring clip links for quick fitting on most drives, split pin links for larger chains, or riveted links for high speeds and heavy loads
• Load and speed - for high speeds and heavy loads, consider riveting links and avoid cranked links where possible
• Material and finish - choose links that match the chain material and finish, such as standard steel, nickel plated, or stainless steel
• Quality and brand - choose links from reputable suppliers that match the chain manufacturer’s quality

How to fit a triplex connecting link

Fitting a connecting link correctly is important for safety and reliability:

• Isolate the drive - switch off and isolate the machine before working on the chain
• Prepare the chain - wrap the chain around the sprockets so the two ends meet, using a chain puller if needed to hold them together
• Insert the link - push the pins of the connecting link through the two end rollers of the chain from the back
• Fit the plate - fit the removable side plate over the pin ends, pressing it fully into place
• Fit the fastener - fit the spring clip, split pins, or rivet the pins, depending on the link type
• Check the spring clip direction - fit the spring clip so its closed end faces the direction of chain travel, reducing the risk of it catching and coming off
• Check the joint - make sure the link moves freely and is fully secured
• Set the tension - adjust the chain tension, then turn the drive by hand to check it runs smoothly

FAQ - All you need to know about triplex links

What is a triplex link?

A triplex link is a connecting or repair link designed for triplex roller chain, which has three rows of rollers side by side.

What does Nr. 26 mean?

Nr. 26 usually refers to a connecting link with a spring clip, used to join roller chain into a loop.

What does the 3 in 08B-3 mean?

The 3 shows the chain is triplex, with three strands. For example, 08B-1 is simplex, 08B-2 is duplex, and 08B-3 is triplex.

What is the difference between BS and ANSI chain links?

BS links suit British Standard roller chain, and ANSI links suit American Standard roller chain. They have different dimensions, even at the same pitch, and are not interchangeable.

How do I know which chain I have?

Check the markings on the chain plates, which often show the size and standard. If there are no markings, measure the pitch, roller diameter, and inner width, and compare them with a chain chart.

What is a cranked link?

A cranked link, also known as an offset link, allows a chain to have an odd number of links. It is weaker than standard links, so it should only be used when an odd number of links is unavoidable.

Which way should the spring clip face?

The closed end of the spring clip should face the direction of chain travel. This helps stop the clip catching on anything and coming off.

Can I reuse a connecting link?

It is best to fit a new connecting link, especially on heavy-duty drives. Spring clips and split pins can weaken once removed, and worn links can fail.

When should I use a riveting link instead of a spring clip link?

Use riveting links on high-speed and heavy-duty drives, where a permanent, strong joint is needed and there is a higher risk of a clip coming loose.

Can I join new chain to old chain?

It is not recommended. Old chain will have stretched through wear, and mixing it with new chain can cause poor running, noise, and rapid wear on the sprockets.

How do I know when to replace triplex chain rather than repair it?

Replace the chain if it has stretched beyond the manufacturer’s wear limit, if many links are worn or damaged, or if the sprockets are also worn. Repairing a heavily worn chain usually only gives a short-term fix.