Patent ID: 7985907

Claim:
An action unit for an upright piano, comprising: a whippen assembly rotatably connected at an intermediate portion thereof to a stationary part of said upright piano and at a lower portion thereof to a key of said upright piano so that said key gives rise to rotation of said whippen assembly while a player is moving said key between a rest position and an end position both defined for said key, and staying at an original position when said key is rest at said rest position; a regulating button mechanism connected to another stationary part of said upright piano, and provided over said whippen assembly; a jack mechanism rotatably supported by said whippen assembly, held in contact with a hammer assembly of said upright piano during the movement of said key from said rest position to an escape from said hammer assembly, brought into contact with said regulating button mechanism on the way of said key toward said end position for said escape, and brought into contact with said hammer assembly on the way of said key toward said rest position; and a return accelerator connected between yet another stationary part of said upright piano and said whippen assembly and urging said whippen assembly toward said original position of said whippen assembly.