Keyboard musical instrument having hammer stopper changed between free position and blocking position through turn on horizontal plane

摘要

A keyboard musical instrument is a combination of an acoustic piano, a silent system and an electronic sound generating system, and the silent system includes a change-over mechanism and a shank stopper connected to the change-over mechanism so as to be changed between a free position and a blocking position, wherein a change-over mechanism gives rise to a rotation of the shank stopper around vertical axes spaced apart from each other on a horizontal virtual plane so that the hammer stopper is free from a twist.