For drilling rig operators, track de-chaining is a frustrating and potentially dangerous problem. While the harsh working environments rigs operate in—often encountering soil, mud, and stones—make occasional track slippage almost unavoidable, frequent de-chaining is a red flag. It signals an underlying issue that needs immediate attention, not just for operational efficiency but critically for safety, as unexpected track loss can lead to accidents.
Understanding why your rig’s tracks are frequently coming off is the first step to resolving the issue. It’s often more complex than just debris getting caught. Faults in key undercarriage components or even operational errors can be the culprit.
Let’s explore the common reasons behind drilling rig track de-chaining:
1. Tensioning Cylinder Failure
The tensioning cylinder (track adjuster) is crucial for maintaining the correct track slack. If the track is too loose, it’s highly prone to coming off.
- Check for:
- Has the tensioning cylinder been properly greased? Lack of lubrication can impede its function.
- Are there signs of oil leakage from the cylinder? A leak indicates a failing seal and loss of tensioning pressure.
2. Excessive Crawler Track Wear
Like any component subject to constant friction and stress, crawler tracks wear out over time.
- Key Wear Points: Pay attention to the wear on chain ribs and chain drums (bushings).
- Impact: Significant wear on these parts changes the track’s geometry and fit, making it much easier for the track to dislodge from the rollers, idlers, and sprocket.
3. Worn or Damaged Chain Guards
Most modern drilling rigs feature chain guards (track guards) for a reason – they play a vital role in keeping the track aligned and preventing it from slipping off, especially during turns or on uneven terrain.
- Inspect: Check the chain guards for signs of significant wear, bending, or damage. Worn guards offer reduced protection and increase the likelihood of de-chaining.
4. Drive Motor Ring Gear / Sprocket Wear
The drive sprocket (or ring gear, as mentioned in the source) engages with the track links to propel the rig.
- Problem: If the teeth on the sprocket are severely worn, they can no longer mesh correctly with the track. This poor engagement can cause the track to jump or slip off under load.
- Solution: Worn drive sprockets typically need replacement.
5. Damaged Carrier Rollers
Carrier rollers support the weight of the track along the top section between the sprocket and the front idler.
- Common Failure: Oil leaks from the roller’s seals are a frequent issue. This leads to lubrication loss, accelerated internal wear, and eventual seizure or collapse of the roller.
- Result: A damaged or seized carrier roller disrupts the track’s path and tension, contributing to de-chaining.
6. Damaged or Misaligned Guide Wheel (Front Idler)
The front idler (guide wheel) plays a critical role in guiding the track and maintaining tension alongside the tensioning cylinder.
- Inspect Carefully:
- Are any mounting screws missing or broken?
- Is the central slot, where the track links are guided, deformed or damaged?
- Consequence: Damage or misalignment here can cause the track to feed incorrectly onto the undercarriage, leading directly to de-chaining.
Conclusion: Prioritize Undercarriage Health
While environmental factors and occasional operational mishaps can cause a track to come off, persistent de-chaining points to a mechanical issue within the rig’s undercarriage. Regularly inspecting track tension, wear levels on tracks and sprockets, the condition of rollers, idlers, and chain guards is essential. Addressing these common causes proactively not only prevents frustrating downtime but is paramount for maintaining a safe operating environment. Don’t ignore frequent track de-chaining – investigate the cause promptly.