| 摘要 |
A combination acoustic mode and electronic mode grand piano is provided including a hammer shank stop rail that intercepts the hammer shank when operating in its electronic mode, so that the hammer cannot complete its normal travel to strike its corresponding string(s) when its key is actuated. The positioning of the hammer shank stop rail is actuated by a user-operated control that, when placed into the "acoustic" mode, raises the hammer shank stop rail to a non-engaged position that does not interfere with the normal movements of the hammer shank. When in the "electronic" mode, the control lowers the hammer shank stop rail into an engaged position where it intercepts the hammer shanks of the piano, thereby preventing each hammer head from striking its respective string(s). When in the engaged position, the wire cam also causes an "early escapement rail" to be moved into a location such that flexible "early escapement tabs" are moved into positions just beneath the letoff button of each of the key actions, thereby preventing a harsh "feel" or "touch" as perceived by the human player of the piano. In a second embodiment of a combination dual-mode piano, a hammer head stop rail is provided for an upright piano which intercepts the hammer head when in the electronic mode. When placed into the acoustic mode, the hammer head stop rail is rotated to a non-engaged position that is not within the normal path of the hammer travel. When operated in the electronic mode, the actuating arm is rotated such that the hammer head stop rail becomes positioned directly in the path of travel of the hammer heads of the upright piano where they will impact directly against the stop rail. In the illustrated embodiment, the stop rail comprises a deflectable member that is coated with a sound and vibration absorbing material, such that when the hammer head impacts the stop rail, the deflectable member somewhat displaces, as the hammer head impacts against this member. The hammer head stop rail also includes a sound and vibration absorbing pad that is brought into position against the strings of the piano, thereby tending to dampen any acoustic vibration that may otherwise become induced in the strings.
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