FB Chain manufactures and supplies quality leaf chain, products and assemblies for the most demanding of materials handling applications.

Our leaf chain, and its machined parts, is produced from specialist steels to withstand shock loads, reduce elongation, maintain strength and resist wear.

All FB Chain manufacturing procedures are compliant with the ISO 9000 Quality Management System. Each batch of leaf chain is issued with a test certificate to enable it to be traced back through the manufacturing process to the raw material.

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Assembly

Our leaf-chain assembly solutions are tailor-made to address specific applications and to ease scheduling and supply-related issues.  Leaf chain is cut to length to eliminate stock loss and support lean manufacturing practice.

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Traceability

All FB Chain's leaf chain and anchor bolts have a highly visible link showing the tracking or batch number which enables the complete manufacturing  process to be traced back to its raw materials.

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Consultancy

FB Chain provides exceptional quality, service and consultation. We will work closely with your design, engineering, procurement and scheduling departments to provide solutions for all your leaf chain needs.

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Introduction

Leaf Chain is our business

FB Chain is the UK arm of the FB Group, owned by Swedish company Addtech AB, and is the leading UK manufacturer and supplier of industrial chain.

As each FB subsidiary focuses on a particular niche product, the group as a whole is able to offer customers highly specialised chain and associated parts for a wide range of different industries and applications.

Customers are able to order their required chain (including leaf chain, conveyor chain, roller chain, sawmill or sharp top chain) from their local FB branch which will then be shipped from the factory where it is produced.

What makes our chain superior?

  • Link plates are re-punched to correct the taper that typically results from conventional blanking.
  • The re-punched whole is accurate and parallel which considerably increases the fatigue strength of the chain.
  • Precision grinding the rivet pins, and double-punching the link plates, ensures there is constant pin to plate contact and allows all chain elements to share the load equally by reducing the bearing pressure.
  • Shot peening fortifies chain link plates and pins against fatigue failure by removing blemishes and creating beneficial compressive stresses on the surface.
  • The correct seating of the chain elements is assured by pre-loading the assembled chain to increase chain life by minimizing the initial chain elongation.
leaf chain for telehandlers

Leaf chain history

About Leaf Chain

Leaf chain is a form of rollerless chain commonly used in a variety of materials handling applications and lifting apparatus including:

  • Telehandlers, forklift trucks, lifts and hoists
  • Mobile elevated platforms
  • Machine tools (planers, drills, machine heads and machine centres)
  • Counter-weight balances (jacks, doors and gates)

Leaf chain is a simple construction of link plates and pins. Sheaves (not sprockets) are used to change the direction of the chains.

EM131 Chain labels

Because the component parts of leaf chain are dimensionally similar to standard roller chains, the economic production of leaf chain is largely dependant on factories that are able to produce large quantities of roller chain.

Leaf chain history

Leaf chain history

  • The earliest evidence of the use of chain dates back to 225BC with records of simple bucket chain link systems being used to lift water from wells in Asia and Egypt.
  • In the 16th century, Leonardo Da Vinci sketched designs of plates and pins with metal fittings that bear a striking resemblance to leaf chain.
  • In the late 1800s, flat card used in the textile industry looked very similar to what we call leaf chain but was used to transfer rotary power.
  • Galle chain, patented in 1874, was the first industrial chain designed for lifting. It added extra outer links to bush chain to increase its strength and was used to lift lock gates.
  • Further development of leaf chain is linked to the increased use of forklift trucks during the Second World War.
  • Early forklifts used roller chain with the roller removed, however, as lifting capacity increased, more links were added and the bush was also removed.
  • During the 1950s and 1960s, most roller manufacturers were producing what we now think of as leaf chain.
  • The first standard for leaf chain was published in 1971.

The leaf chain part number system

The leaf chain part number system

Leaf chain part numbers are not arbitrary. The different combinations of letters and numbers represent the type of chain and describe the pitch as well as the chain lacing. With practice, these dimensions can be gleaned from the part number instantly.

Series

The initial two letters in the leaf chain part number refer to the leaf chain series - for example, AL, EL-LL and BL-LH series leaf chains.

  • AL series (American Light) chain, manufactured to the ANSI B29.9 standard, is constructed from American standard roller chain components. AL series chain is lightweight chain used for light load lifting applications and machine tools.
  • EL-LL series (European Light – Leaf Light) chain, manufactured according to ISO4347, DIN8152 and NFE26107, is also constructed from roller chain components but to European standard. Like AL series chain, EL-LL series chain is a lightweight chain used for light load lifting applications and machine tools.
  • BL-LH series (Leaf Heavy) chain, manufactured according to ISO4347, DIN8152, ANSI B29.8 and NFE26107, is the only leaf chain that is constructed from specific leaf chain components. BL-LH series leaf chain is heavier duty chain than ALand EL-LL series and so is the most common chain used for forklift trucks, lifting and materials handling equipment.

Pitch

The first one or two digits (depending on whether the part number has three of four digits) refer to the pitch of the chain and vary according to the series.

  • AL series chain is measured in 8ths of an inch - but only the numerator of the fraction is given. For example, 4 represents 4/8” which can be reduced to ½” and 10 represents 10/8” which can be reduced to 1 ¼”.
  • EL-LL and BL-LL series chain is measured in both 8ths and 16ths of an inch. For example, BL12 represents 12/8” and LL24 represents 24/16” which can both be reduced to 1 ½”.
  • The metric pitch can then be found by dividing the numerator by the denominator and multiplying by 25.4 as 1 inch is equal to 25.4 mm.

Examples

AL1066

From the part number, we can tell that

  • this is a lightweight American standard chain made from roller chain components.
  • the pitch is 10/8” which can be expressed as 1 ¼” or 31.75mm.
  • it is constructed from 6 inner plates, 4 intermediate plates and 2 outer plates.

6x6 chain lacing (3)

EL544-LL1044

From the part number, we can tell that

  • this a lightweight European standard chain made from roller chain components.
  • the pitch is 5/8” or 10/16” which can also be expressed as 15.875mm.
  • it is constructed from 4 inner plates, 2 intermediate plates and 2 outer plates.

4x4 chain lacing (1)-1

BL623-LH1223

From the part number, we can tell that

  • this is a sturdy chain made from specific leaf chain components.
  • the pitch is 6/8” or 12/16” which can be expressed as ¾” or 19.05mm.
  • it is constructed from 3 inner plates and 2 outer plates.

2x3 chain lacing (2)-1

Leaf chain assemblies

Leaf chain quick find

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Leaf chain standards

Leaf chain standards

Tensile strength

When selecting the right leaf chain for a particular application, the most important consideration is that the minimum tensile or breaking strength of the chain is safe and legal for the load and type of machinery.

While all chain manufacturers publish their minimum tensile strength requirements, it is often up to the design engineer to make a decision as to which tensile figure on which to base their design. Most good quality leaf chain manufacturers will exceed any international standard by 20%.

It should be noted that it has been common in the industrial chain industry to focus on tensile strength as an indication of leaf chain product quality.

Making leaf chain stronger may seem easy - ie by just increasing the hardness of links and pins. But this method can result in the chain becoming brittle and less resistant to shock loads and can reduce its fatigue limit.

The graphs below show tests on two chains.

low-cost-chain

The chain above is from a low-cost manufacturer who hardened the pins and plates to increase tensile strength.

In this example, the chain failed suddenly as a brittle failure - and with no prior evidence of ductility or plastic degradation.Higher-tensile-chain

The example above is a chain using higher grade material, but with lower hardness, which has resulted in a higher tensile load.

Traditional calculation of working load

Most chain company catalogues contain a formula for working out a chain’s recommended working load which can be used to give you an indication or starting point for chain selection.

However, many companies are wary of unsupported design, as this method can often result in over specification.

Chain standards

Many countries issue their own standards which normally mirror the two international standards - ISO4347 or BS29.B.

The International ISO standard contains LL & LH (BL) and the American standard contains BL (LH). The key difference in the standards is that the ISO standard contains a minimum fatigue requirement.

Conversion of an inch in the American standard to European metric also throws up some small dimensional differences.

It is recommended that the chain standards are used as a dimensional reference only, particularly for chain anchors bolts slots, as this will ensure interchangeability.

While all chains should meet the minimum tensile requirements of the standard, each manufacturer will have their own data which may be significantly different.

There are currently three levels of safety requirements that a chain must fulfil. The first is the Machinery Directive 2006/42/EC, implemented in the UK as the Supply of Machinery (safety) Regulations 2008, which requires a minimum safety factor of 4:1.

This means that the minimum tensile strength of a leaf chain must be four times the maximum load it is used to support.

However, most leaf chain manufacturers recommend a greater safety factor.

For example, ISO 4347:2015 requires a factor of 5:1. Different legal requirements also apply to different types of machines.

Standard forklifts and telescopic handlers, for example, require a factor of 5:1; while man-up forklifts and passenger lifts require a factor of 10:1 and 20:1 respectively.

Other factors that need to be considered when selecting a leaf chain are:

  • The number of load cycles
  • The number and size of shock loads
  • Internal bearing pressure
  • The diameter of the chain roller/pulley
  • Fatigue
  • Environmental conditions

Machinery standards

All machinery supplied in the European economic area must comply with the machinery directive 2006/42/EC (with specific reference to 4.1.2.4. Pulleys, drums, wheels, ropes and chains) which sets out the design requirements for chain.

It’s important to bear in mind though that this directive is generic and covers all types of chain used in lifting.

For leaf and roller chain, most manufacturers would neither approve or recommend a design which uses the 4:1 safety factor contained in the machinery directive as it is a minimum standard only.

  • The main standard for telehandlers is: EN1459 Rough-Terrain Trucks - Safety Requirements and Verification - Part 1: Variable Reach Trucks.
  • The main standard to consider for boomed access platforms is: BS EN 280:2013+A1:2015 (which covers mobile elevating work platforms, design calculations and stability criteria.)
  • The requirements for chain systems are contained in sections 4.9.1.1 of EN 1459-1 and 5.5.3.1 of EN 280.

Design engineers should note however that the Mobile Elevated Work Platform (MEWP) standard refers to the chain system and a decision needs to be made as to which parts of the design are included in the chain system.

Many machine manufacturers take this to mean chain and chain anchor bolts, supplied together, as a chain assembly.

Leaf chain wear life

Leaf chain wear life

Environmental impacts

The environments in which leaf chain mechanisms operate can differ widely.

Forklift truck chain, for example, may be exposed to normal outdoor moisture, abrasion from sand or grit or highly corrosive industrial atmospheres.

Some of the key environmental challenges include:

  • Moisture – which produces corrosive rusting and reduces the strength of the leaf chain through pitting and cracking.
  • Low Temperature – if a lift truck’s daily activity involves constantly moving in and out of cold stores, condensation will form on the outer and bearing surfaces of the chain. This moisture will cause stiffness and eventually corrosion fatigue cracking which reduces the service life of a forklift truck chain.
  • Chemical solutions or vapours – chemical solutions and vapours can corrode leaf chain components, anchor pins, anchor bolts, anchor blocks and cause microscopic stress cracking. Depending on the extent of exposure, cracks can propagate across the forklift truck chain leading to complete, and abrupt, failure.
  • Abrasives - accelerated wearing or scoring of the pin surfaces and link plate apertures will lead to reduced forklift chain strength. The bearing surfaces of these articulating members are not readily accessible which means that the wear is not usually visible - so the extent of chain wear should be regularly inspected using a precision tool such as a Chain Wear Gauge.

Each specific forklift truck chain application should be evaluated for risk, according to the extent of environmental exposure and the area of operation.

Leaf chains should be frequently inspected and a schedule for the replacement of worn leaf chains established to avoid potential forklift truck chain failure.

The frequency of forklift truck inspections must comply with the minimum legal requirement as detailed in LOLER 98, regulations 9, 10 and 11, for the Thorough Examination and Inspection of Industrial Truck Leaf Chain.

It is also recommended that forklift truck users are familiar with all the relevant Health and Safety guidance notes and particularly PUWER 98.

Others guidance documents published by the British Industrial Truck Association (BITA GN15 & GN28) and the technical bulletins of Fork Lift Truck Association (FLTA TB 02, 05, 08 & 09) should also be noted.

Inspection procedure development for leaf chain should continue until a projected time of replacement can be estimated.

By its very nature, a forklift truck leaf chain should be viewed as an expendable item and a safe leaf chain replacement schedule established.

It is advisable that forklift truck chains that operate in arduous, harsh or aggressive environments (including cold stores, marine, corrosive chemical, metal manufacturing or processing, cement/ aggregate processing and brine processes) have their leaf chains and leaf chain anchor pins replaced after no more than 4000 operating hours - or two years (whichever is the shorter).

If a lifting mechanism uses a single leaf chain (e.g. free lift section), any leaf chain anchor bolts should also be replaced together with the chain.

Dynamic impulse and shock loads

Dynamic impulse or shock loads occur when high-velocity movement is followed by a sudden abrupt stop.

For forklift truck leaf chain, this type of movement can impose exceptionally high loads which exceed the fatigue endurance limit.

An adverse movement may result from carrying a suspended load over an uneven surface such as tracks, potholes or rough ground or when trying to 'inch' loads beyond the rated capacity of the leaf chain or lifting mechanism.

Continual operation of leaf chain that results in “bounce”, under otherwise normal and apparently safe operation, will cause cyclic (impulse) loading, eventually leading to fatigue failure.

This cyclic loading on the leaf chain is intensified when the operation is running at high speed (when the actual load on the leaf chain will be roughly doubled.)

If a leaf chain is repeatedly loaded above its fatigue endurance limit, it is likely to experience premature fatigue cracking.

It is not always easy to establish the fatigue endurance limit of forklift truck leaf chain, but it will usually be lower than its certified SWL.

Typically, forklift truck leaf chains will become worn (elongated) well before fatigue sets in and so it is only when a chain is subjected to continuous impulse loading that fatigue failure occurs.

Fatigue cracks (which are not necessarily visible) are caused by periodic on-off loading above the endurance limit of the leaf chain.

The factors that determine when fatigue failure will occur include:

  • the magnitude of the load
  • the frequency of its occurrence
  • the endurance limit of the forklift truck chain

These sorts of cycles and environments can make it difficult to predict forklift truck leaf chain life so it is essential to conduct regular inspections to evaluate leaf chain replacement life.

Lubrication

Effective lubrication is a key factor in the longer service life of leaf chain.

It is common for forklift truck chain users to assume that their leaf chain has been adequately lubricated. But nevertheless, friction corrosion, turned pins, metallic friction, stiff joints, noisy operation and pitting still occurs.

This is especially the case when the applied lubricant adheres only to the exterior of the leaf chain and doesn’t penetrate the leaf chain joints.

The life of an adequately lubricated forklift truck chain is estimated to be 60 times longer than that of a dry running leaf chain. And even temporary dry running will shorten leaf chain life considerably.

Selecting the correct lubricant for forklift truck leaf chain can make a huge difference.

Most chain lubricants for example are designed for transmission or motorcycle applications, whereas the loading and operations of leaf chain require a lubricant with totally different properties.

effects-of-lubrication

The graph above shows the results of a test which simulated the work a leaf chain would do when fitted on a forklift truck mast.

These leaf chains were loaded to near their maximum working load and repeatedly raised and lowered. In this test three identical lengths of leaf chain were used - and each applied with a different type of oil.

At 40,000 cycles, the difference between the best performing leaf chain and the worst was an amazing 3.8 times.

At this point, the A sample seized and would no longer articulate. The two other leaf chains continued for a further 40,000 cycles, double the amount compared to oil A.

Another important factor to consider is keeping the leaf chains constantly lubricated. Forklift truck chains that operate outdoors, that are in environments where they are regularly washed or that work within cold stores (where they are subject to condensation) will require an oil that will stay in place.

Under these circumstances, it is unlikely that operators will re-oil their forklift chains regularly enough to achieve the leaf chain’s optimum life.

In another leaf chain study, the same lubricant was applied to three identical samples of leaf chain, which were then rinsed with water for one minute and then subjected to a comprehensive salt spray test where a hot salt water mist was blown over the leaf chain at regular intervals.

Rinsing the leaf chain with water beforehand simulated normal usages, such as when a forklift truck chain is used in outdoor applications or cold stores.

This accelerated corrosion test was able to assess the corrosion resistance of the leaf chain without having to leave it outside for months, or years, on end.

Oil A after 40 hours in salt spray test

Oil B after 40 hours in salt spray test

Oil C after 15 hours in salt spray test

leaf-chain-1

leaf-chain-2

leaf-chain-3

The image above shows that the leaf chain lubricated with oil C performed well in the wear test, but did not perform at all well in the corrosion test. This was due to its lower viscosity, which helped the oil to penetrate between the pin and plates, but which also made it more easily removed by washing.

For forklift truck chain working outside or in cold stores, the oil would not stay in place long enough to perform its main function of lubricating the forklift truck leaf chain. Oil B, however, remained in situ longer on the leaf chain and therefore offered the best mix of wear and corrosion resistance.

Many forklift chains get encased in dirt and dust, which prevents oil from flowing to the important load bearing regions of leaf chain between articulating link plates and pins.

It is vitally important that all leaf chains are kept free of dirt and debris to ensure effective lubrication of the critical contact areas.

 

Leaf chain inspection

Leaf chain inspection

The table below provides detailed information on the symptoms of leaf chain wear, the probable causes and the corrective measures that should be taken.

Symptom

Appearance

Probable cause

Correction

Worn contour chain-1

Normal wear on sheave
Abnormal wear rubbing on guides

Replace leaf chain when 5% worn
Check Leaf chain alignment or increase clearance

Worn surfaces on outer plates or pin heads chain-2

Misalignment, rubbing on side flanges

Check leaf chain alignment and correct clearance as necessary

Tight joints chain-3

Dirt or foreign substance packed in joints or corrosion or rust or bent pins

Clean & re-lubricate leaf chain
Replace leaf chain

Missing parts chain-4

Missing at original assembly

Replace leaf chain

Abnormal protrusion or turned pins chain-5

Excessive internal friction caused by high loading and inadequate lubrication

Replace leaf chain, improve lubrication and eliminate overload conditions

Cracked plates (fatigue)

chain-6

Crack from aperture towards edge of linkplate at 90º to line of pull. Note there is no linkplate distortion

Loading beyond chain's dynamic capacity (above fatigue endurance limit)

Replace chain with leaf chain of larger dynamic capacity or eliminate high load condition or dynamic (impulse) overloading

Fractured plates (tension mode)

chain-7

Note material distortion

High overload

Replace leaf chain and correct cause of overload

Arc like cracked plates (stress corrosion) chain-8

Severe rusting or exposure to acidic or caustic medium, plus static pressure at press fit (between pin and pin linkplate). No cyclic stress is necessary for this phenomenon to occur.

Replace leaf chain and protect from hostile environment.

Enlarged holes

chain-9

High overload

Replace leaf chain and correct cause of overload

Corrosion  

Exposure to corrosive environment

Replace leaf chain and protect from hostile environment.

Worn leaf chain anchor bolt connecting pin  

Normal wear

Replace worn leaf chain components and always when fitting new leaf chains

 

Leaf chain test certificates

All replacement forklift truck chains should be supplied with a chain test certificate which indicates the chain’s minimum breaking load and proof load (which shows that the chain is able to support a minimum of one and a half times the safe working load.)

While most forklift manufacturers and maintenance firms place a lot of emphasis on receiving these test certificates, many will file them away without looking at them.

The various different types of forklift truck chain have been consolidated over the past decade with the result that, when ordering leaf chain, many firms simply ask for the generic part number from the International Leaf Chain Standard ISO4347 e.g. BL634.

However, this standard only refers to the dimensions of the leaf chain elements and the minimum tensile strength.

If you only quote the generic part number when ordering your leaf chain and do not check the breaking load of the leaf chain you purchase, you will not necessarily receive the correct product quality or consistency for your particular application.

It is important to check that the safe working load stated on the certificate exceeds the capacity of the lifting equipment. The vast majority of forklift truck manufacturers actually require leaf chain with a greater minimum tensile strength than the International Standard ISO4347.

High-quality leaf chain will be manufactured to ensure the optimum balance between strength, wear rate, fatigue life and resistance to shock loading.

It should also ideally have a consistently higher breaking load than the International Standard.

The safe working load of a leaf chain will usually be shown on a test certificate in kilonewtons (kN). If the capacity of your equipment is given in kilograms or pounds you will need to refer to the safe working load conversion table.

It is also important to ensure that the safety legislation quoted on the test certificate is reliable and up to date and that it meets the current requirements of The Machinery Directive, LOLER and PUWER.

Leaf chain system design

Leaf chain system design

Chain anchor thread selection

When designing a chain system, it’s important to consider adjustment as a result of elongation due to wear. Over time, chain will increase in length due to articulation around the chain sheave or pulley.

To ensure that chain is not used once its elongation limit has been reached, it is recommended that the amount of adjustment should be set to allow no more than 3% of the chain length which articulates the pulley.

For example, a 5000mm long chain (of which 3800mm wraps the pulley) should have no more than 114mm of adjustment.

As a starting point, you should design the chain anchor to be as strong as the tensile strength of the chain and the final design must have a strength equal to or greater than the working load plus the safety factor machine.

We recommend calculating the strength in three places: the shear and tensile of the head and the tensile strength of the threads (as per the diagram below.)

Our experience is that chain anchors will need to be made from a material or heat treated to have a strength around 850kN mm².

 

Chain anchor in place

Chain termination

The preferred choice, and the strongest connection is achieved when leaf chain ends on inner links and fits internally to the chain anchor to ensure the maximum number of sheer faces and the greatest tensile strength.

If space is limited, the chain can connect to the chain anchor on the outer links with the chain rivet pin being the widest part.

However, when using this method, the chain should be joined to the anchor with a riveting or cotter pin unit.

It is vital that a chain anchor pin is never pushed through the chain outer links, as this can result in the load being taken by only the two outer links.

Chain Length

If the termination, or last links, of the chain are both on either the inner links or the outer links, the chain length can be adjusted by x 2 the chain pitch.

If the ends are odd (i.e. one inner and one outer) the chain length can be moved by x 1 the chain pitch.

Chain Tension and adjustment

Typically each stage of the boom has a set of chains for extension and retraction. These act against each other, so great care must be taken when adjusting each chain as it will have the opposite effect on the opposing chain.

Over-tensioning can be a problem, both during the set-up of a new machine and in the carrying out of machine maintenance, as it adds load to the chain which can result in it operating above its tensile capacity.

Some leaf chain manufacturers supply an equation for calculating the required torque on chain anchor nuts to remove chain sag.

While this is practical while the machine is being built in the factory, doing this in the field is difficult.

Setting a minimum and maximum distance the chain should sit from the boom and/or the position of nuts on chain anchor can help ensure chain tension is more constantly applied in service and without the need for equipment.

Bearing pressure

A lot of the focus of the machinery standard is on meeting minimum safety factors. But this can sometimes lead to poor choices. When comparing chains with equal tensile strength, for example, it is recommended to select the one with the largest bearing area.

The bearing area calculation in mm² is as follows:

Plate Thickness (mm) x Total Articulating Plates x Pin Diameter (mm)

Calculating bearing area

In the example above we have two chains with a minimum tensile strength of 127kN (ISO standard 97.5kN) - however, the BL646 (4x6 lacing) has 50% greater bearing area than the BL644.

Ideally, it’s advisable to keep bearing pressure between 0.15–0.18 kN/mm².

The bearing pressure calculation is as follows:

(kN/mm2) total load on chain (kN) ÷ bearing area (mm²)

With booms, there is often more space availability in width than there is in height as the booms pass over each other. This can result in the decision to select a wide small pitch chain to help keep the pulley diameter small.

But as the width and number of links increases, the fatigue limit reduces. Turning forces of more links acting on the pin also increase the chance of breaking the press fit between the outer plate and rivet pins - which can result in the chain needing to be replaced after even a short time of increased load or poor lubrication.

Although 8 x 8 and 10 x 10 chains are still shown in many chain catalogues, for example, they are not in the international standards and should be selected only as a last resort.

Fatigue

The fatigue strength of a leaf chain is linked to the number of articulating links, with an increasingly uneven load dispersal occurring as more links are added.

Chain components, like any stamped components, have tolerances and a leaf chain with more links has longer pins which bend more under load.

High quality chains will have close tolerances on the chain pitch and the bores in the link plates will be high precision. The application of a high pre-load to a leaf chain at the end the manufacturing process can also bed the components in and increase fatigue strength.

While the general process for leaf chain is the same for each manufacturer, they will each have their own ideas on the features that they believe give the best performance.

ISO 4347 added a minimum fatigue requirement in the 2015 version. All good manufacturers should be able to supply fatigue data for each size of leaf chain.

Care is required when making comparisons as the test length can be 3 million and to 10 Million cycles and the stress range impact on the results.

The table below gives the fatigue limit approximation as the number of plates increase:

 

Plate combination

 

Good quality brands

Average or medium quality brands

Defective or poor quality brands

2 x 2 and 2 x 3

20%

13%

6.70%

3 x 4 and 4 x 4

14%

9%

4.50%

4 x 6 and 6 x 6

12%

7.70%

4%

8 x 8

10%

6.30%

3%

Pulley design

Below is the recommended dimension of a leaf chain pulley/sheave.

The running diameter should be a minimum of 5x the pitch of the chain.

The larger the diameter, the longer life of the chain. So a chain pulley with only x 4 pitch will reduce chain life by 25% while a pulley with 7 x pitch will increase chain life by 33%.

The running surface of the pulley needs to be hard, and slightly more than the chain hardness, so it is the chain plates that wear and not the chain pulley. If space is an issue, adjustments can be made to the flange diameter and the flange angle - however, it is recommended that the flange is always above the centre line of chain.

When designing a leaf chain pulley (also known as a leaf chain roller or leaf chain sheave), it is important to consider the following international standard: ISO4347 - Leaf Chains, Clevises and Sheaves. Dimensions, measuring forces, tensile strengths and dynamic strengths.

For normal wear life rates, it is recommended that:

  • The minimum running diameter of the pulley is equal to 5 x the nominal pitch of the chain
  • The minimum width between the flanges is 1.05 times the pin length (or width over riveted bearing pins)
  • The minimum outside diameter (or flange diameter) is the running diameter plus the link plate height

The above dimensions can vary according to space and application requirements, but it should be noted that any deviation from the recommended standard will result in either an increase (or decrease) in chain wear.

By increasing the diameter of the pulley, for example, the angle of articulation will decrease, leading to less wear.

By decreasing the diameter of the pulley, the angle of articulation will increase, leading to more wear.
The speed and frequency of operation must also be considered when designing pulleys, rollers or sheaves for leaf chain.

It is also recommended that the working faces of the pulley are hardened to 50 HRC (Rockwell C Hardness) minimum.

The pulley must be designed to be harder than the leaf chain - so that it is the easily-replaceable chain and not the pulley that is subject to wear.
Pulley design

Leaf chain assemblies

Leaf Chain products

SuperShield leaf chain

If your forklifts operate outside or in harsh environments, or frequently need to be washed down, SuperShield corrosion will save you the cost and effort of replacing rusting forklift chain.

FB SuperShield coating is a three-stage process where leaf chain is pre-treated, then applied with a coating and a further top coat.

In our test cabinet (which aims to simulate harsh, corrosive environments) standard leaf chain begins to rust after around 12 hours while zinc plated leaf chain rusts after around 70 hours. 

FB SuperShield corrosion resistant leaf chain stays rust-free even after 500 hours - or the equivalent of five years without rust.

Once Supershield corrosion resistant leaf chain has been brought into service, it can be treated like any other chain and must be regularly lubricated to prevent elongation caused by wear.

  • Salt spray performance - 500hrs guaranteed in 5% neutral salt spray test (ISO3768 / ASTM B117).
  • Solvent resistant - Curing the metal surface ensures resistance to solvents, gasoline, brake fluids, etc.
  • Zero hydrogen embrittlement - The absence of acids or electrolysis in the coating process assures freedom from hydrogen embrittlement, which is commonly associated with electroplating processes.
  • Superior heat resistance - 290°C to 300°C

SuperEndurance Leaf Chain

SEB SuperEndurance fatigue-resistant leaf chain has solid seamless bushes pressed into two inner links. The bushes are made to be as perfectly round as possible, which increases and optimises the internal bearing area of the chain to distributes the load evenly across the pin and increase its resistance to wear.

The addition of O-ring seals helps to keep the grease locked inside the bush which again reduces chain wear and extends chain service life.

All the major dimensions , breaking loads and working loads of SEB SuperEndurance chain are interchangeable with FB standard chain so customers can safely fit SEB SuperEndurance chain to any machine currently using standard chain.

  • Corrosion protection - SEB chains are treated with a zinc flake coating which increases corrosion protection to more than 6 times that of an untreated chain.
  • Lubrication - The special O-ring holds lubrication in the key load carrying areas resulting in SEB chain requiring less lubrication which reduces operating costs and limits the amount oil which is washed off into the environment.
  • Extended service life - The extended life of SEB chain not only results in customers buying less chain but also means that trucks spend less time ‘out of service’. These major savings significantly reduce overall fleet operating costs.
  • Reduced bearing pressure - The O-ring and bush construction of SEB SuperEndurance chain reduces bearing pressure and retains the oil in place which extends chain life.

Leaf chain pins

For each size of leaf chain we hold a number of different chain anchors pin lengths in stock. 

Chain anchor pins should be selected to ensure the pin grips the leaf chain anchor (clevis) correctly and that it does not allow excess lateral movement.

All our chain anchor pins are made from a special blend of carbon alloy steel which is heat treated and ground to achieve excellent strength and wear resistance

Leaf chain cutting tool

The leaf chain cutting tool is a hand tool designed to be used by service technicians and maintenance engineers to enable them to make final adjustments to the length of leaf chain.

It is a very useful item when working on site, as it removes the need for using a grinder to remove the chain rivet head.

The heavy duty design is most suitable for ½ to ¾ pitch leaf chains but can also be used for some larger sized chains.

The leaf chain cutting tool pushes the pin straight out and does not require the use of a hammer and punch to make the final disconnection.

All moving parts can be replaced if required, so with some basic care, this robust tool can form part of a technician's toolkit for many years.

Leaf chain assemblies

Leaf chain assemblies

In addition to supplying individual leaf chains, anchor bolts, blocks and pins, FB Chain offers pre- assembled leaf chain kits that can be issued directly onto assembly lines.

Our leaf chain assembly kits can be tailor-made to suit an OEM’s specific requirements, to address a particular application or assembly need and to ease scheduling and supply-related issues.

In a leaf chain assembly, leaf chain is pre-cut to length (which eliminates chain stock loss) and assembled with individually designed leaf chain anchor bolts and blocks (leaf chain clevises).

  • Coatings, lubricants and surface finishes are also applied to all parts according to application.
  • Leaf chain and anchors (clevises) can be delivered in temporary protective plastic tubing to reduce chain contamination and assist clean assembly.
  • Permanent protection can be provided in the form of heat-shrunk Neoprene applied to specially lubricated chain and is recommended for difficult environments.
  • Specific heat treatments, integral bushings or bearings, for example, can all be supplied to specification.
  • Complete component packages bring together the whole family of parts required and including items as diverse as composite bushings and nylon stops.
  • Other complementary parts can be supplied including mast pulleys (sheaves), chain rollers and mast pivot pins.
leaf chain for telehandlers