Boom part for tower crane, has lower-, right-, and left framework sections flexibly connected with each other and disassembled into three pieces, where all joints between framework sections are releasable to fold boom part together

摘要

The boom part has lower-, right-, and left framework sections (I-III) flexibly connected with each other, where all joints (A-C) between the framework sections are releasable to fold the boom part together. The framework sections are disassembled into three pieces and exhibit a square cross-section.