Abstract: An upright keyboard instrument comprises a prescribed number of keys that are interlocked with actions, hammer assemblies, and a plate spring unit, which is interlocked with a loud pedal. When the key is depressed, the action is activated to drive the hammer assembly, thus producing a musical tone. Each of plate springs is normally arranged close to an end portion of a whippen included in the action. Upon depression of the key, the end portion of the whippen comes in contact with the plate spring to cause a resistive force, which is transmitted back to a player's finger depressing the key. When the loud pedal is depressed, the plate spring departs from the end portion of the whippen, which becomes free to rotate upon depression of the key, thus realizing loudness effect on sound.

Abstract: A keyboard instrument such as an electronic piano comprises a keyboard structure that is basically identical to the keyboard structure of an upright piano except hammer assemblies and a struck portion attached to an action bracket. Each of the hammer assemblies is constituted by a hammer shank and a pseudo hammer, one of which is used to strike the struck portion having a multilayer structure including an elastic member (e.g., a plate spring) sandwiched between buffer materials. The elastic member has a prescribed number of striking areas in correspondence with keys arranged on a keybed, wherein the striking areas are gradually increased in weights and bends (or deflections) in a pitch descending order from higher pitches to lower pitches. Thus, it is possible to simulate weight factors and bends (or deflections) of strings actually struck by hammer felts in an upright piano.

Abstract: An upright keyboard instrument comprises a prescribed number of keys that are interlocked with actions, hammer assemblies, and a plate spring unit, which is interlocked with a loud pedal. When the key is depressed, the action is activated to drive the hammer assembly, thus producing a musical tone. Each of plate springs is normally arranged close to an end portion of a whippen included in the action. Upon depression of the key, the end portion of the whippen comes in contact with the plate spring to cause a resistive force, which is transmitted back to a player's finger depressing the key. When the loud pedal is depressed, the plate spring departs from the end portion of the whippen, which becomes free to rotate upon depression of the key, thus realizing loudness effect on sound.

Abstract: A keyboard instrument such as an electronic piano comprises a keyboard structure that is basically identical to the keyboard structure of an upright piano except hammer assemblies and a struck portion attached to an action bracket. Each of the hammer assemblies is constituted by a hammer shank and a pseudo hammer, one of which is used to strike the struck portion having a multilayer structure including an elastic member (e.g., a plate spring) sandwiched between buffer materials. The elastic member has a prescribed number of striking areas in correspondence with keys arranged on a keybed, wherein the striking areas are gradually increased in weights and bends (or deflections) in a pitch descending order from higher pitches to lower pitches. Thus, it is possible to simulate weight factors and bends (or deflections) of strings actually struck by hammer felts in an upright piano.