Buckets of the bucket wheel excavators: failures and redesign

Design of the buckets of the bucket wheel excavators has to meet the set of the functional requirements imposed by the processes of: (a) soil cutting; (b) filling; (c) transportation of the grabbed soil; (d) emptying. Optimal conduct of each of these processes imposes requirements, which are often in mutual collision. Except functional requirements, bucket structure has to meet, naturally, rigidity as well as strength criterion. During exploitation in harsh working conditions, failures of buckets occur relatively frequently. There are two basic types of bucket failures: structural and technological. In this paper, two bucket structural failures as well as one technological bucket failure are presented. Investigations' results pointed out that structural failures are caused by 'design-in' as well 'manufacturing-in' defects. Technological failure of the bucket was also of the 'design-in' type. Besides that, the redesigned buckets' are presented. Exploitation after the reconstruction fully confirmed the validity of the presented reconstruction design