Fret retractable neck for stringed musical instruments

A stringed musical instrument that can be played either as a fretted instrument or as a fretless instrument of a type comprising a fingerboard having a fingerboard surface defining fret slots with movable frets therein, said stringed musical instrument comprising:

• a linearly-movable cam structure movably mounted within an interior cavity of the fingerboard for impinging on each of the frets for selectively moving the frets between a fretted position in which they extend outwardly through the fret slots in the fingerboard exteriorly of the fingerboard surface, and a fretless position in which they are in the interior thereof approximately at or below the fingerboard surface.

A stringed musical that can be played either as a fretted or as a fretless instrument of a type comprising a fret fingerboard having a fingerboard surface defining fret slots with movable frets mounted therein, said stringed musical instrument comprising:

• a cam structure movably mounted within an interior cavity of the fingerboard for impinging on respective ones of the frets for selectively moving the frets outwardly through the slots in the fingerboard to extend exteriorly of the fingerboard surface and for allowing the frets to be returned into the interior of the fingerboard approximately at or below the fingerboard surface;
• laterally-extending internal members attached to each of the frets positioned in the interior of the fingerboard and biasing means impinging on the laterally-extending internal members for biasing the frets inwardly;
• wherein the fingerboard is an elongated neck and the laterally-extending internal members extend away from the frets in the direction of elongation of the neck.