1. Scope and purpose
This guide describes the necessary maintenance steps for industrial chain conveyors (roller chains). The aim is to ensure safe and reliable operation by regularly checking chain elongation, sprocket wear and correct lubrication in accordance with DIN 8187.
2. Safety instructions
WARNING: Danger from moving parts and stored energy. Before starting any work, complete isolation from the energy supply (lockout/tagout - LOTO) is essential. Personal protective equipment (PPE) must be worn in accordance with the risk assessment: safety shoes S3, cut-resistant gloves, safety glasses and tight-fitting work clothing.
3. Required tools and materials
| Tools/Material | Specification | quantity |
|---|
| Digital caliper | Measuring range min. 500 mm | 1 |
| Torque wrench | Range 10 - 100 Nm | 1 |
| Laser alignment tool | Precision +/- 0.5mm | 1 |
| Chain oil | High temperature resistant, viscosity ISO VG 150/220 | As required |
| Test mirror/flashlight | LED, IP67 | 1 |
4. Pre-maintenance checklist
| Element | Exam | Criteria (acceptance/rejection) | Notes |
|---|
| Chain guard | Visual inspection | No deformations/firm assembly | - |
| Emergency stop switch | Functional test | Immediate stop when actuated | Check before LOTO |
| Chain tension | Manual check | Sag max. 2-3% of the axis distance | - |
5. Step-by-step procedure
- Carry out the LOTO procedure: Disconnect the machine from the power supply and secure the main switch.
- Measuring chain elongation: Measure the length over 20 chain links in the load strand. Error: Measurement in the slack side leads to incorrect values. The permissible elongation is a maximum of 2% of the nominal length. If the limit is exceeded, the chain must be replaced.
- Check sprocket wear: Inspect the tooth flanks for run-in marks (shark tooth profile). Wear of more than 10% of the original tooth width requires replacement.
- Lubrication: Applying the lubricant directly into the joint space. Error: Only superficial lubrication of the rollers does not reduce wear.
- Adjust tension: Adjust the chain tension to 2-3% sag of the axle distance at central load.
6. Post-maintenance checklist
| test | Expected result | Actually | Pass/Fail |
|---|
| Release | Chain runs without blockages | - | - |
| Noise level | Normal running noise | - | - |
| Lubricant | Evenly distributed | - | - |
7. Troubleshooting
| Symptom | Probable cause | Corrective action |
|---|
| Excessive noise | Poor lubrication / wear | Relubricate / check chain |
| Chain falls off | Incorrect tension/offset | Correct tension/align |
| Chain stretched unevenly | Overload / One-sided wear | Replace chain / check load |
8. Maintenance schedule
| task | Frequency | Duration (estimated) | Qualification |
|---|
| Visual inspection | Weekly | 15 minutes | Technician |
| Lubrication | Monthly | 30 mins | Technician |
| Elongation measurement | Quarterly | 60 minutes | Specialist |
9. Spare parts reference
| Description | Specification | UNITEC category |
|---|
| roller chain | DIN 8187, ISO 08B-1 | Chain conveyor components |
| sprocket | 20 teeth, pre-drilled | Drive technology |
| Lubricant | High performance chain oil | Operating materials |
Order your spare parts directly via our UNITEC-D e-catalog.
10. References
- DIN 8187: Roller chains
- VDI 3643: Maintenance of chain conveyors
- OEM manual for the respective drive unit
