1

When the key is depressed, it lifts an intermediate lever. The damper, connected to the intermediate lever, releases the string.

2

After a small free run, the jack of the intermediate lever pushes the hammer up.

3

The hammer separates from the jack halfway to the string and proceeds to hit the string because of its momentum.

4a

If the key is immediately released, the string is damped again, generating a staccato sound, and then the mechanism goes back to its resting position.

4b

If the key is pressed down, the undamped string is free to resonate, generating a longer sound. The hammer then goes back down to the top of the jack.

5b

When the key is fully released, the hammer goes back to its resting position and string is damped again, muting the sound.