IMPROVEMENT OF PUZZLE LOCK TYPE COMPRESSION RING

摘要

PROBLEM TO BE SOLVED: To provide a mechanical coupling part for a compression ring to be improved in term of holding capacity and effectively block the possibility of re-opening during transport. SOLUTION: A compression ring is provided at the tongue-form member 14 of a male part 11b with an expansion head part 15. The expansion head part is partitioned by laterally extending contact surfaces 23 and 24 forming a right-angled part in cooperation with side contact surfaces 31 and 32. In this case, the side contact surfaces 31 and 32 of the expansion head part is migrated to lateral end part contact surface 33 of the expansion head part 15 through a curved part. To remarkably reduce a tendency for the male part and the female part of a mechanical coupling part to radially move to each other, upsetting operation to displace a material to the joining spots 50 and 51 of some contact surfaces of laterally extending contact surfaces is performed.