Patent ID: 6639133
Filing Date: 2003-10-28
Classification: G10C

Abstract:
A universal piano action for emplacement in upright pianos and grand pianos below and above strings; comprising a hammer shank carrying a piano hammer; a base end of said hammer shank being pivotally connected to a support member; a substantially rigid pivotal jack supported by a spring means being positioned on a rear portion of a piano key; said spring means pressing said pivotal jack against an abutment in a direction towards a pivot of said support member; upon depressing said piano key a lifting surface of said pivotal jack lifting a substantially straight lifting surface of said hammer shank in a sliding manner; said undersurface of said hammer shank urging said lifting surface of said pivotal jack in said sliding manner pushing said pivotal jack in opposition to said spring means supporting said pivotal jack into a substantial incline in a direction away of said pivot of said support member; said incline being effected by gravity of said hammer shank and said piano hammer upon said lifting surface of said pivotal jack; angle of said pivotal jack in said incline varying with amounts of force applied to said piano key; said pivotal jack remaining in said incline until release of said piano key returning said pivotal jack to its normal upstanding attitude; said piano hammer being propelled towards a tensioned horizontal string; and rebounding from said tensioned horizontal string during said lifting surface of said pivotal jack being in contact with said undersurface of said hammer shank; said lifting surface of said pivotal jack locking onto a variable point on said undersurface of said hammer shank; whereby positioning said piano hammer at a variable rebound position; said lifting surface of said pivotal jack unlocking from said variable point on said undersurface of said hammer shank upon releasing said piano key permitting said piano hammer to return to its normal at rest position from said variable rebound position; said variable rebound position of said piano hammer being effected by amounts of force applied to said piano key and to tension strength of said spring means supporting said pivotal jack and to weight of said piano hammer; said universal piano action operating without escapement let off biasing means.