L&H has historically used a heavy-duty bushing throughout their undercarriage systems with great success and extended life in excess of 30% more than the industry standard. L&H engineers explored using the heavy-duty bushing in alternative components and assemblies and recently tested the bushings in an equalizer lug on a 74yd dipper.
These bushings were running on a 4100XPC at a coal mine in the Powder River Basin and monitored over 10,000 hours to test the benefits of running L&H’s heavy duty bushing in comparison to the standard bushing the mine had been running which had resulted in an average life of 2,000 – 3,000hrs.
As a historical problem area for many customers, if the standard bushings were not monitored in the equalizer they would wear through the side walls, causing damage to the bores and consequently increasing rebuild costs. Along with extending bushing life, the mine had an additional goal in mind to grease the bushings as little as possible to avoid the time and safety exposure that it created during maintenance.
Grease Intervals & Test Results
- 0 – 5,283 hrs: bushings were greased at the beginning of each shift or twice daily, which was standard practice
- 5,283 – 6,900 hrs: bushing were greased once per day
- 6,900 – 9,524 hrs: bushings were greased
weekly between 300 PM days
- 9,524 – 10,002 hrs: no grease
The original wall thickness of the heavy-duty bushings was 1.487” and the post-test bushings at the thinnest points were 1.375” and 1.290” respectively. It can be determined that the bushings had several thousand hours left to run until life. Consequently, the mine has purchased additional sets of bushings for this application and commented,
“L&H has definitely provided a bushing product that could last the life of a dipper.”