Chain Guards
- Make sure that the chain guards are adjusted so that the guards do not touch the conveyor chain. The recommended clearance between the guard and the conveyor chain is 6.35 mm (0.25 inch).
 | |
| Illustration 1 | g01127959 |
- Verify that the chain guards are not excessively worn in order to protect the chain.
- If visible wear is present and the chain is exposed, the guards need to be replaced.
Conveyor Chain
There are several methods for determining the stretch of the conveyor chain. Each of these methods is listed below in reverse order of preference.
- Feel for excessive motion between the bushing and the pin.
- Inspect the amount of remaining adjustment in the chain adjustment. Once most of the adjustment has been used, the chain and the sprockets need to be replaced.
 | |
| Illustration 2 | g01127961 |
- Measure ten pitches of chain on both strands. The nominal length of a new chain is 69.85 cm (27.5 inch). If the chain measures 71.95 cm (28.325 inch), convenient replacement should be planned. If the chain measures 72.6 cm (28.6 inch), the chain needs to be replaced as soon as possible.
Note: When you replace the chain, always replace both strands and install new sprockets.
Note: When you follow the above guidelines, also examine the chain for cracks in the links. Cracked links need to be replaced.
 | |
| Illustration 3 | g02003893 |
(A) Ten pitches of the chain | |
Drag Bars
- New drag bars have a thickness of 31.75 mm (1.25 inch). Once the bars have been worn to a thickness of 21.2 mm (0.833 inch), replace the drag bars.
 | |
| Illustration 4 | g00861312 |
- When you inspect the drag bars, the assemblies for the roller pin should also be checked for loose pins or cracked pins. If any of the pins appear worn or damaged, replace the pins. If any of the pins are loose, replace the pins.
 | |
| Illustration 5 | g00861324 |
Auger Conveyor
 | |
| Illustration 6 | g00861022 |
The corners of new augers are square. As the augers wear, the thickness and diameter become smaller. When the edge wears to a point, the auger should be replaced.
Drag Pans
There are two ways to measure the wear of a drag pan.
Ultrasonic Measurement
- Use an ultrasonic gauge in order to measure the thickness of the drag pans. New drag pans have a thickness of 10 mm (0.4 inch). Once the pans are worn to a thickness of 3.175 mm (0.125 inch), the drag pans need to be replaced.
- Take the measurement at the center of the drag pan. The center is the thinnest part of the drag pan. You may need to alternate replacing the middle pans due to wear patterns.
Inspection of the Hardware
 | |
| Illustration 7 | g00861346 |
The drag pans should be replaced when an allen wrench can no longer be inserted into the bolt. At this point, the bolts are no longer countersunk and the bolt heads have begun to wear.
Note: If the drag pans are worn to approximately 6 mm (0.24 inch), you must make a decision. If the drag pans have been used for two years, the pans will probably last for another year of similar use. If the drag pans have only been used for one year, the pans should be replaced in order to avoid replacing the pans during paving season. This decision involves some discretion.