Why Industrial Chain Loops Prefer Even Number of Links

Chains are a common mechanical component used in various applications such as transmission, traction, and other industrial purposes. When designing or purchasing industrial chains, one crucial consideration is the total number of links required for the chain loop to fit the intended machinery or system. The key question is: should the chain consist of an odd or even number of links?

In this article, we’ll explore why an even number of links is generally preferred for chain loops in industrial applications and the differences between using even and odd link chains.

Basic Structure of a Chain

A typical chain consists of five primary components: inner link plates, pins, rollers, bushings, and outer link plates. These elements form individual chain links, with the inner link (composed of the inner plates, rollers, and bushings) and the outer link (composed of the pins and outer plates) being the two fundamental building blocks. The links alternate to form a continuous chain loop.

Why Even Number of Links Is Preferred for Chain Loops

1. Balanced Load Distribution: Chains with an even number of links are more balanced. When the chain is looped, the number of inner and outer links will be the same, which allows the load to be evenly distributed across the entire chain. This balanced load distribution reduces the risk of uneven wear and tear, thereby extending the chain’s lifespan.
2. Simplified Installation: Chains with an even number of links make the installation process straightforward. Since both ends of the chain have an equal number of inner and outer links, the chain loop can be easily closed without requiring special connectors or adjustments. In contrast, chains with an odd number of links will require a transition link (often called a “half-joint”), which complicates the installation.
3. Stable Power Transmission: When operating, a chain with an even number of links ensures smooth and stable power transmission. The uniform distribution of load helps maintain consistent tension and reduces the chances of one side of the chain bearing more weight than the other. This stability lowers the chance of mechanical failure due to uneven wear, which is especially important in high-load applications.
4. Common Applications: The majority of industrial applications, such as power transmission, conveyor systems, and other mechanical drives, use chains with an even number of links due to their durability and stability. The even link chain is the standard choice in most industrial machinery.

Why Odd Number of Links May Be Used

1. Transition Link Requirement: Chains with an odd number of links cannot form a balanced loop, as the number of inner and outer links will be unequal. To close the loop, a transition link must be used. A transition link is a special link where one side is designed to fit the inner link dimensions, and the other side fits the outer link dimensions. This ensures that the chain can form a closed loop despite the odd number of links.
2. Reduced Load Capacity: A chain with an odd number of links, due to the use of a transition link, generally has a reduced load capacity. The transition link typically carries a lower load-bearing capacity—about 65% of the usual load limit of a standard chain—due to its unique design and the presence of a non-standard link configuration.
3. Unbalanced Load: Since odd-numbered chains don’t have a symmetrical link configuration, the load distribution is often not uniform. This can result in higher wear on one side of the chain, causing an uneven tension distribution. Over time, this leads to faster degradation of the chain and associated components, such as sprockets.
4. Specialized Applications: Odd-numbered chains are typically used in cases where fine-tuning the length of the chain is necessary, or in situations where an even-numbered chain would not fit properly in the application. They might be used in specific systems or for temporary adjustments, but their application is limited compared to even-numbered chains.

Conclusion

• Even-numbered chains are the preferred choice in most industrial applications because they provide better load distribution, easier installation, and longer service life. They are ideal for systems that require stable power transmission and high load capacity.
• Odd-numbered chains are generally used for special adjustments or when an even-numbered chain cannot fit properly. However, they require a transition link to complete the loop and typically have a lower load capacity and unbalanced load distribution, making them less suitable for high-load or continuous operations.

In summary, while odd-numbered chains may have niche applications, even-numbered chains are typically the more reliable and durable option for most industrial chain-driven systems.