US 4,338,847 AGranted

Electromagnetic devices for actuating piano keys

OwnerJohn F. Brennaninventor

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Abstract

Electromagnetic devices for actuating piano keys are responsive to music in an encoded format, for example as might be contained on a magnetic tape or phonograph record, to selectively actuate the keys with controlled forces and for selected durations. A separate device is provided for each key, and the devices are operable to authentically reproduce musical renditions. In one embodiment, a single electromagnet is associated with each key rearwardly of the piano headboard, and an energizing signal applied thereto is controlled to determine the intensity and duration of note played. In another embodiment, a plurality of electromagnets are associated with each key rearwardly of the headboard, and are selectively energized to determine the intensity and duration of note played. It is also contemplated to mount various arrangements of electromagnets within a housing, and to place the housing across the front of the keyboard to actuate the keys.

Claims12

Dependent claims

In combination with a piano having a piano key mounted for pivotal movement about a fulcrum, said piano key having a forward end to a forward side of said fulcrum which is depressed or moved downwardly to play a note, a piano key actuating system comprising a first electromagnet having a winding across which an energizing signal may be applied;

a second electromagnet having a winding across which an energizing signal may be applied;
means for movably mounting said first electromagnet above an upper surface of said forward end of said key for movement toward and away from said upper surface;
means extending between said first electromagnet and said upper surface of said key for depressing said forward end of said key upon downward movement of said first electromagnet;
means for fixedly mounting said second electromagnet above said first electromagnet, said first and second electromagnets being mounted so that the same present opposed but spaced pole faces to each other;
and means for interconnecting said first and second electromagnet windings such that upon application of an energizing signal thereacross like magnetic poles are developed at said opposed pole faces, whereby said first electromagnet is repelled away from said second electromagnet and toward said upper surface of said key to depress said key and strike a note on said piano.

2 more elements

a second electromagnet having a winding across which an energizing signal may be applied;
means for movably mounting said first electromagnet above an upper surface of said forward end of said key for movement toward and away from said upper surface;
means extending between said first electromagnet and said upper surface of said key for depressing said forward end of said key upon downward movement of said first electromagnet;
means for fixedly mounting said second electromagnet between said first electromagnet and said upper surface of said key, said first and second electromagnets being mounted so that the same present opposed but spaced pole faces to each other;
and means for interconnecting said first and second electromagnet windings such that upon application of an energizing signal thereacross unlike magnetic poles are developed at said opposed pole faces, whereby said first electromagnet is attracted toward said second electromagnet and toward said upper surface of said key to depress said key and strike a note on said piano.

2 more elements

Dependencies are inferred from the claim text.