The piano's heart
The Keyboard / Action Assembly of an upright piano
The keyboard and action assembly in an upright piano is vertically arranged. The hammer heads acts like standing pendulums. Differing to the grand piano keyboard/ action assembly, a reduced part of the weight of the hammer heads react upon the keys through the level system of the mechanism. For this reason, the balancing weights are located in the rear part of the key leverage. This secures a balanced and dynamic touch weight.
The keyboard and action assembly of an upright piano - details