(57) A frame 25 supports keys 135 corresponding to white piano-keys and keys 140 corresponding
to black piano-keys, for pivoting about an axis 15 parallel to the piano keyboard.
The keys 135, 140 are narrower than white piano-keys and are preferably of equal width.
Each key 135 has a white key engaging lower surface 136 as long as a white piano key.
Each key 140 has a black key engaging lower surface 146 as long as or shorter than
a black piano key. Depression of any key 135 depresses only one white piano key, and
depression of any key 140 depresses only one black piano key.
|
|
