Patent ID: 6888052

Claim:
A key actuation system for a keyboard instrument of the type having a plurality of keys, each key being pivotally supported and having a front end that is depressed by a player to play a note, the actuation system comprising: a plurality of actuators operable to move at least some of the plurality of keys, the plurality of actuators together comprising: a block of ferromagnetic material having a surface with a plurality of bores defined therein, the bores each having a diameter; a winding disposed in each of the bores, each of the windings having a hole defined therein; a piston at least partially disposed in each of the holes, each piston being in mechanical communication with one of the keys such that movement of the piston causes movement of the key, the pistons each having a width; and a ferromagnetic flux plate having a plurality of openings defined therethrough, the flux plate being disposed on the surface of the block of ferromagnetic material with the openings generally aligned with the bores, the openings each having a width that is less than the diameter of the bores such that the flux plate partially closes off the upper end of each bore; wherein energizing one of the windings causes the corresponding piston to move relative to the winding, thereby moving one of the keys.