| 摘要 |
PURPOSE:To simplify shape of a snapper and obtain its minaturization, by using a ball screw and lock nut mechanism. CONSTITUTION:An upper part 17a of a lock nut housing hole 17 is formed to circular shape of internal diameter enough for permietting rotation of a lock nut fixing groove 17b cut with a similar shaped groove for fixedly fitting the hexagonal lock nut part 22. If large shocking force is axially applied, relative displacement force is generated btween a snapper main unit 1 and movable unit 3. In this case, large friction force is generated between a screw ball 35 and screw shaft 23, and a shaft 2 can not be rotated, then a coil spring 24 is compressed to perform the displacement downward. In this way, the lock nut part 22 is fitted into the groove 17b, and the shaft 2 is suppressed its rotation and downward displacement. In case of application of a static load due to thermal expansion or the like, because the coil spring 24 is not compressed, the shaft 2 is rotated to move the movable part 3 downward. |
