In the early days, electric rope shovel manufacturers used Whisler-style lips that had mechanically attached adapters secured by hammer-type locks. Although the hammer-type locks worked well to secure the adapters, they were dangerous for users to install due to the risk of injury from metal fragments breaking off and striking users. This drove the evolution to screw-type locks to secure the adapters.
However, the locks created issues with the adapters becoming loose, requiring ongoing lip maintenance and retightening of the adapter during operations. As a result, additional steel pieces had to be welded to the lip to keep adapters better stabilized. This created different maintenance requirements during the repair of the bucket. The challenges were clear: adapter wear, high maintenance requirements, and safety concerns with hammer usage