7.1.5 Inspection

Chains are reliable components of a transmission machine. If you selected the proper chain and use it within its specified conditions, the chain will last for a long time.

However, you must perform regular inspections on the chain to make sure it is in good condition and operating correctly. Perform inspections monthly or more often if the chain is used in harsh environments. Why are inspections important? Over the life of a chain, the pins and bushings wear gradually. There may have been an unexpected shock load on the line, or a malfunctioning oven might expose the chain to very hot conditions.

During an inspection, make sure to check for the following conditions:

Cracks in the link plates (Figure 7.10).
Cracks in the rollers (Figure 7.11).
Rotated pins (Figure 7.12).
Wear on the end surfaces of link plates (Figure 7.13).

If you find any of these conditions, take immediate steps to correct the problem. A quick checklist is included in Table 7.2. In addition, some troubleshooting tips are included in Section 7.1.6.

**Table 7.2** Inspection Checklist
Procedure	Inspection
Visually check the chain during operation	In addition to the items to check during operation given in Section 7.1.3, also confirm that the lubrication conditions are suitable. (Look at both the method and amount of lubrication.)
Stop the chain and carefully inspect each part of the chain and sprocket	Check the external cleanliness, corrosive, and lubrication conditions; also look for scratches or other damage to the link plate side and edge surface, pin edges, and roller surfaces. Inspect for pin rotation and the gap between the plate and the pins. Inspect the sprocket teeth surfaces and teeth side surfaces for scratches or marks Measure the elongation of the chain due to wear Check the flex of the chain and the spin of the rollers When using a terminating device for lift applications, inspect the wear of the terminator and the wear of the pins. Also, check for proper installation.

Figure 7.10 Example of a Crack on a Link Plate

Figure 7.11 Cracks on the Rollers

Figure 7.12 Rotation of the Pins

Figure 7.13 Wear on the End Surfaces of the Plates