| 摘要 |
PROBLEM TO BE SOLVED: To obtain a roll-forming die for producing a self lock bolt with which a self lock bolt with a slit part having loosening preventive effect is easily and inexpensively produced, and to obtain a self lock bolt 10 which has a slit part formed into a single screw thread to thereby be easily screwed and have sufficient loosening preventive effect. SOLUTION: In a pair of roll-forming dies which can form a screw part in the bolt by a roll-forming method, the one die is the roll-forming die 1 having coarse pitch-thread forming screw and forming the screw thread of the self lock bolt and the other is the roll-forming die 2 for producing the self lock bolt used as the roll-forming die for forming the slit part. With the use of the above roll-forming die for producing the self lock bolt, the self lock bolt with the screw thread exhibiting sufficient loosening preventive effect is easily and inexpensively produced through a single roll-forming operation. Further, the roll-forming die for producing the self lock bolt is provided for producing the self lock bolt which has the slit part formed into a single screw thread to thereby be easily screwed and has sufficient strength and the loosening preventive effect by changing the depth of the slit part to thereby increase spring back effect, and the self lock bolt produced with the die is provided. COPYRIGHT: (C)2004,JPO
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