The Complete Guide to Chain

6.1.3.2 Function Features

  1. High rigidity.

Large pitch conveyor chains are designed to carry heavy loads and endure rough loading. Of course, there are limits to the chain's integrity, and it is important to consult the manufacturer for details.

Let us check the chain's resistance to bending. The following formula shows the relationship between bending moment, M, and stress:

M = σZ = 1/6 × σ × H × t2
σ: stress on side plate
H: side plate height
t: side plate thickness

Using the equation, let's compare the effects of side plate thickness (t) on chain rigidity when tensile strength, side plate height (H), pin diameter, and bushing diameter are held constant.

Here are two examples. Case 1 reflects design considerations for a large pitch conveyor chain; Case 2 is for a small pitch conveyor chain.

Case 1.
Bending moment: M1 = 1/6 × σ × H × t2

Case 2.
t2 = t/2
σ2 = 2σ (in order to maintain the same tensile strength)
M2 = 1/6 × σ2 × H2 × (t2)2 = 1/6 × 2σ × H × (t/2)2
Bending moment: M2 = 1/12 × σ × H × t2

Therefore, the large pitch conveyor chain (Case 1) can withstand twice the moment (M) of small pitch conveyor chain (Case 2).

  1. Large pitch conveyor chain is designed to operate in harsh conditions. However, certain environments may affect the side plates, which can lead to stress-corrosion cracking, for example. This is a rare occurrence even for heat-treated side plates of this series.
  2. The chain is designed with relatively large clearances between components. Typically, even if foreign material gets between the chain parts, the rollers will continue rotating, and articulation of the links is not easily impaired.
  3. In Table 6.2, different materials are listed for each chain part of frequently used series. This lets you create a chain specifically for your operating environment at an economical cost. In Table 6.2, the "O" mark designates available materials for the chain parts. Table 6.3 shows the relation of materials and the chain parts.
  4. Attachments have high strength. Take the commonly used A attachment as an example. During operation, it is subjected to bending and twisting forces. Bending moment and twisting moment are calculated according to formulas shown below.

Bending moment (M) = 1/6 × σ × H × t2
Twisting moment (T) = A × τ × N × t2

The allowable values of M and T are quite high for large pitch conveyor chain compared with small pitch conveyor chains. Attachments have higher resistance to breakage during operation, but verify the bending and twisting moments. Manufacturers can help you determine the appropriate chain size and attachment for an application.

Table 6.2 Typical Material of Commonly Used Chain Series
  Non-Heat-Treated Steel Heat-Treated Steel 400 Series Stainless Steel 304 Stainless Steel Cast Iron
Side Plate Available Available Available Available Not Typically Used
Pin Not Typically Used Available Available Available Not Typically Used
Bushing Not Typically Used Available Available Available Not Typically Used
Roller Available Available Available Available Available

Available : Available  Available : Not Typically Used

  1. It is relatively easy for users to modify chain attachments, by machining or welding, to fit specific applications. Consult with the chain manufacturer in advance to avoid damaging the chain.
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