| 摘要 |
PROBLEM TO BE SOLVED: To keep a Luer-Lok part from being broken even when a connection part is excessively screwed in, by forming the lower final end part of at least one of spiral threads of the Luer-Lok part at a position higher than the top surface of a bottom part between both cylinder parts. SOLUTION: Lower final end parts of at least one of at least two, normally two threads (a) and (b) parallel with each other or preferably all the threads formed on the inner circumferential surface 2' of an external cylinder part 2 of a Luer-Lok part are formed at a position higher than the top surface 5 of a bottom part between two cylinder parts. Therefore, even when the lower final end part of the thread a' of the connection part 8 is screwed in beyond the lower final end part of the thread (a) formed on the inner circumferential surface 2' of the external cylinder part 2, since there is not thread (a) at this part, the lower final end part of the thread a' is bent upward to weaken a force pushing the external cylinder part 2 outward. This enables avoiding of the concentration of a stress about the root of the external cylinder part 2, thereby preventing breakage near the root. |
