How A Piano Works
Esntially, when a piano key is presd down, its tail pivots upward and lifts a lever that throws a hammer against the strings for that key's note. At the same time a damper is raid from the strings, allowing them to vibrate more freely. The following is a much more detailed description of how the action works; the numbers in parenthes refer to the accompanying diagram of the action of a grand piano.
The piano key (1) is a lever that pivots on a balance pin (2). When the player depress the key, the tail ris and the capstan screw (3) in the key pushes up the whippen (4), which is hinged. The free end of the whippen ris, taking with it an L-shaped piece called the jack, or escapement lever (5), and the repetition lever (9).
The jack pushes the knuckle, or roller (6), a roll of felt that is fixed to the hammer shank (7); the hammer thus ris. The jack's upward motion is stopped when its protruding end hits the regulating button (8). The hammer flies up away from the jack and strikes the appropriate
证监会考试内容strings. The repetition lever (9) also ris, but only until the end where the jack pass through it and touches the drop screw (10); this lever stays raid until the key is relead.
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The hammer falls back, but
only partway. It is stopped
by the knuckle (6) hitting
the raid repetition lever
(9). The jack (5) can thus
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slip back under the partially
raid hammer shank and
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the same time, thebad组合
backcheck (11) keeps the
hammer from rebounding习惯的英语
against the strings. If the key is partly relead,
the hammer moves free of the backcheck, and the repetition lever stays raid. If the player again depress the partially relead key, the jack (5) can once more push the knuckle (6) and hammer shank (7) upward. (This system allows rapid repetition of notes before the key and hammer have time to return to their original positions. It was an important improvement over early, simpler piano actions.)
Meanwhile, the tail of the key has also pushed up the damper lever (12), which lifts the damper
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(13) off the strings for that key. When the key is even partially relead, the damper falls back onto the strings and silences the note.
Grand Piano Action (Microsoft Encarta)
When the key is fully relead, all parts of the mechanism return to their original positions becau of gravity. Unlike grand pianos, upright pianos cannot rely on gravity to cau everything to return to place. In a grand piano the action sits horizontally on the key; in an upright piano the action is adapted so that it sits more or less vertically. Becau it cannot completely rely on gravity, it includes various springs and small strips of cloth to pull some of the action parts back into place.
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"Piano (musical instrument)," Microsoft® Encarta® Online Encyclopedia 2006 © 1997-2006 Microsoft Corporation. All Rights Rerved.
Grand Piano Diagram
(Microsoft Encarta)
Vertical Piano Action
