Patent ID: 8513508

Claim:
An upright piano, characterised in that: a) within the overall lever-hammer 3 , the total weight of the hammer butt ( 18 ) plus balance hammer ( 19 ) exceeds the weight of the hammer ( 22 ) by at least 60%; b) the arm of the lever-hammer ( 3 ), i.e. that segment which joins the overall barycentre B of said lever-hammer ( 3 ) to the pin ( 21 ) of the hammer butt ( 18 ), consequently has a measurement of less than 65 millimeters; c) the barycentre B of the lever-hammer ( 3 ) is shifted rearwards from the vertical V passing through the pin ( 21 ) in the opposite direction to the string ( 1 ) by a distance exceeding one centimeter such that, at the moment of striking, the segment which joins the barycentre B to the pin ( 221 ) of the lever-hammer ( 3 ) (i.e. the arm of this lever) forms with the vertical V a positive angle of at least 7°; d) a spoon ( 31 A) is added, symmetrical to and opposite the spoon ( 31 ) fixed to the wippen ( 10 ) on the other side of the rod ( 26 ) of the damper ( 30 ), this spoon ( 31 A) being hinged, by a lever ( 35 ) provided with a counterweight ( 36 ), to a fixed structure ( 39 , 37 , 6 ; 39 , 37 , 5 ; 32 A, 33 ).