| 摘要 |
PROBLEM TO BE SOLVED: To suppress the occurrence of mechanical noise by stabilizing an engagement state between a key and a hammer body during rotation operation.SOLUTION: A formation 20 is coupled with and fixed to a lower part of a plunger 12 to be movable vertically and integrally with the plunger 12. A slit recessed part 25 formed in the formation 20 has a left wall part 23 and a right wall part 24 perpendicular to an axial direction of a key rotation shaft and is formed in the shape of a slit. The right wall part 23 is parallel with the right wall part 24, and a front end part 37 of a hammer body is sandwiched from both sides by the two wall parts 23, 24. An interval between the wall parts 23, 24 is almost equal to or slightly smaller than the diameter of the front end part 37, and when a key and the hammer body rotate, the front end part 37 slides on the two wall parts 23, 24 of the slit recessed part 25. |
