Key board music instrument of hammer rod brake with spring back hammer assembly and not bending hammer rod

The utility model relates to a chatter upright piano. An electroacoustic system and a hammer actuator are assembled to form a keyboard instrument to generate the chatter in the chatter mode and generate the electrical sound in the electroacoustic mode; the hammer actuator is provided with a rotating shaft extending in the lower space of the lower side of a bottom block of a sound making device of a sound making device assembly; a buffer unit extends to the upper space of the lower side of the bottom block of the sound making device and is connected with a lifting rod arranged between the rotating shaft and the buffer unit, thus, the motion of the hammer can be blocked before the piano string is touched in the electroacoustic mode.