Patent ID: 7781652

Claim:
A grand piano piano action comprising: a repetition base with adjustable heel connection system, wherein said repetition base with adjustable heel connection system comprises: at least two notches or depressions ( 130 ) on the lower surface of said repetition base with adjustable heel connection system, wherein said at least two notches or depressions is 0.2-15 mm in depth and is oblong-shaped with longitudinal axis essentially perpendicular to that of the lower surface of said repetition base with adjustable heel connection system, and a main channel ( 150 ) on the lower surface of said repetition base with adjustable heel connection system, wherein said main channel is 0.2-15 mm in depth and is oblong-shaped with longitudinal axis essentially parallel to that of the lower surface of said repetition base with adjustable heel connection system; and a heel with adjustable repetition base connection system, wherein said heel with adjustable repetition base connection system comprises: at least one ridge or protrusion ( 140 ) on the upper surface of said heel with adjustable repetition base connection, wherein said at least one ridge or protrusion is 0.2-15 mm in height and is oblong-shaped with longitudinal axis essentially perpendicular to that of the upper surface of said heel with adjustable repetition base connection system, and a main rib ( 160 ) on the upper surface of said heel with adjustable repetition base connection, wherein said main rib is 0.2-15 mm in height and is oblong-shaped with longitudinal axis essentially parallel to that of the upper surface of said heel with adjustable repetition base connection system; wherein, said at least one ridge or protrusion is sized to snugly fit within any one of said at least two notches or depressions with proper clearance between the upper surfaces of said at least one ridge or protrusion and the lower surfaces of said at least two notches or depressions to allow for sturdy attachment of said heel with adjustable repetition base connection to said repetition base with adjustable heel connection system by gluing means, and said main rib is sized to snugly fit within said main channel with proper clearance between the upper surfaces of said main rib and the lower surfaces of said main channel to allow for sturdy attachment of said heel with adjustable repetition base connection to said repetition base with adjustable heel connection system by gluing means between said surfaces.