Double Pitch Chain Structure and Components Overview

The double pitch chain is specifically designed for applications requiring long-distance, low-speed transportation. Compared to standard chains with attachments. Its pitch is twice as long (double pitch), making it ideal for specific industrial uses. Below is an overview of its structure and components.

Chain Structure

• Pitch: The double pitch chain has a pitch that is twice as long as standard chains, making it suitable for long-distance transmission systems.
• Chain Plates: The chain plates are generally flat and are designed to bear the tension exerted by the chain.
• Rollers: There are two types of rollers available: R-shape and S-shape. The choice between them depends on the application.
• Sprockets: Double pitch chains can be used with double-pitch sprockets, especially for applications where the sprocket has more than 30 teeth, in combination with S-shape rollers.
• Application: These chains are primarily used for long-distance, low-speed conveying tasks.

Three Key Chain Dimensions

The performance and compatibility of the chain depend on three basic dimensions:

1. Chain Link: The basic unit of the chain.
2. Roller Diameter: The diameter of the roller.
3. Inner Link Width: The width of the inner link.

When these three dimensions are identical, the chain and sprockets can usually be interchanged without issues.

Types of Fits

• Clearance Fit: This occurs when the shaft and hole are manufactured with tolerances such that the hole is slightly larger than the shaft (pin shaft or sleeve), creating a gap.
• Interference Fit: This occurs when the shaft and hole are manufactured with tolerances such that the hole is slightly smaller than the shaft, creating a press fit.

Components of the Chain

1. Chain Plate:

   • The chain plate bears the tension of the chain and is manufactured to a high precision, ensuring high fatigue strength and impact resistance.
   • The precision of the hole for the pin and sleeve is critical, ensuring that the chain maintains its quality.

2. Pin (Pin Shaft):

   • The pin is pressed into the holes of the outer chain plates and secured using rivets (or is simply inserted in the case of hollow pins and plastic chains).
   • The pin absorbs shear stress and bending forces during operation. As the chain bends, the sleeve rotates and slides along the pin, making the pin’s strength and wear resistance essential.

3. Sleeve:

   • The sleeve is pressed into the inner chain plates at both ends and serves as a bearing between the pin and the roller.
   • It is designed to withstand complex stresses while having high wear resistance.

4. Roller:

   • The roller is fitted with a clearance fit between the sleeve and roller to help absorb shock during engagement with the sprocket.
   • During operation, the roller rotates, allowing the chain to move smoothly and reducing friction. Wear resistance is crucial for roller performance.

5. Attachments:

   • The bolts in the chain may feature bolt holes for securing various attachments, depending on the standard types of attachments used.

6. C-Clip / Cotter Pin:

   • The C-clip or cotter pin is a crucial component for preventing the disconnection of chain plates, ensuring the chain maintains its strength and integrity. It is essential to install these components.

7. Inner Link:

   • The inner link consists of two sleeves pressed into the inner chain plates, with a clearance fit between the outer diameter of the sleeve and the roller.

8. Outer Link:

   • The outer link consists of two pins pressed into the outer chain plates. The pins are then secured with rivets to prevent disconnection (in the case of hollow pins and plastic chains, the pins are simply inserted).

This construction gives the double pitch chain its superior load-carrying capacity, low operational friction, and exceptional wear resistance, making it ideal for long-running, high-load applications.