When a leaf chain isn’t properly maintained, this can lead to a shorter service life and higher operating costs of the entire piece of materials handling equipment over time. It’s essential that service technicians know what to look for and how to prevent potential problems as part of their maintenance routine to make chains last longer.
Dan Hargraves, sales manager for FB Leaf Chain, a leaf chain manufacturer based in the U.K., runs a program for service technicians to learn the best kept secrets of leaf chain maintenance. Read on to learn how you can do the same.
Proper lubrication directly impacts equipment performance and leaf chain life. When applied at the right intervals and under the right conditions, chain life can increase by 60% or more.
SELECTING THE RIGHT CHAIN
Leaf chain is a form of rollerless chain commonly used in a variety of materials handling applications and lifting apparatus. It is a simple construction of link plates and pins, with sheaves (not sprockets) used to change the direction of the chains as opposed to standard roller chains that include pins, bushings and rollers.
A quick first step to extending a leaf chain’s life is to select a quality leaf chain that is right for the environment the equipment is in.
DESIGN MATTERS
The rate at which a chain will wear is already dictated by the way it’s been designed into the machine. One of the biggest ways to impact the life of a leaf chain is to make sure the minimum running diameter of a pulley is equal to five times the pitch of the leaf chain.
Increasing the diameter of the surface that the chain will run over ensures there is less articulation on the plates, which leads to less wear and a longer life.
APPLYING LUBRICATION CORRECTLY
Proper lubrication directly impacts equipment performance and leaf chain life. When applied at the right intervals and under the right conditions, chain life can increase by 60% or more.
Apply Lubricant the Right Way
For best results:
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Apply lubricant when the leaf chain is not under load.
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Allow 15–20 minutes of slack to open clearances and help oil reach internal load-bearing areas.
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Apply lubricant directly to each chain link to ensure penetration into friction points.
The goal is to reach the internal surfaces where wear actually occurs.
Using a product with a precision nozzle allows for better control and targeted application, reducing waste and improving effectiveness.
Clean Before Reapplying
“If lubrication is caked on the chain, you won’t even be able to see the chain,” Dan says. “If you don't clean the old lubrication off, it's not going anywhere and the lubricant isn’t going to get on to the internal surfaces.
Takeaway: Clean off all excess lubrication and then lubricate the chain for best results.
Choose the Right Product for the Environment
Lubricants with anti-corrosive properties help prevent rust and seizing. In harsh conditions, selecting both the right chain and the right lubricant is critical.
In one salt mine application, switching from a standard chain to a super shield chain paired with a tougher lubricant extended chain life from three to four weeks to 1.5 years. The chain was ultimately replaced due to wear and elongation — not corrosion.
“That’s a good example of why choosing the right chain and the right lubricant is so important,” he says.
OTHER PREVENTIVE MEASURES
Service technicians should also measure the elongation of the leaf chain. The easiest and fastest way is by using a chain wear gauge. A percentage reading is given without complication and without technicians having to do a mathematical equation.
The wear of a leaf chain is caused by friction between pins and inner plates in the leaf chain link.
As a leaf chain operates under load, friction wears down the pin surfaces. Over time, that material loss causes the chain to elongate.
It is also important to watch for turned pins, which can be hard to see, especially when the leaf chain is overly lubricated.
A turned pin can be a sign that the chain may have an excessive load, while a broken rivet head can show that a chain needs to be replaced.
Tailoring the maintenance specifically to each machine and product can have a massive impact on the life of a leaf chain. Every piece of machinery has a manual with manufacture recommended maintenance intervals. However, the decision to go beyond the bare minimum is up to the service technician looking after the equipment.
That’s where a talented technician is important. They understand the environment they're working in and adapt what they're doing to suit it. Trained service technicians have the biggest impact on chain life.
PHOTO CREDIT: SHUTTERSTOCK/RONALDL
