The Action
Click on the Picture, to see the action mechanism in motion.
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The Action Mechanism:
1. Pressing on the key pushes up on the escapement mechanism.
2. The hammershank is pushed upward.
3. During the hammer's upward motion, at two critical points obstructions disengage elements of the escapement mechanism from contact with the hammershank's knuckle.
4. For the last 1/16 inch of the its motion, the hammer is traveling entirely on its own momentum.
5. Tthe damper is lifted off the string, allowing the string to vibrate when struck.
6. After the hammer strikes, it is caught and held by the backcheck.
7. At the slightest release of the key, the backcheck will move away and free the hammer.
8. The components of the escapement mechanism will reset.
9. The action is then ready for another strike from the key.
Before: The action mechanism
is labeled before the key is pressed by the pianist |
After: The action mechanism is shown
here after the key has been pressed and the string is struck |
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 |
In Depth Hammer analysis: The piano hammer as a nonlinear spring
Main Page
Before the Piano
Progress of the Piano
Inside a Concert Grand
Bibliography