Means for improving the repetition characteristics of an upright piano

Abstract

Means for improving the repetition characteristics of an upright piano action of the type having a hammer for each key, the butt of the hammer being pivotally mounted on a main action rail so that the hammer can be projected from an at-rest position toward a string striking position, a wippen pivotally attached to the main action rail and operatively connected to the key, a jack pivotally connected to the wippen for transmitting the action of the key and wippen to the hammer via the hammer butt to cause the hammer to strike the string when the key is forcibly depressed and a back check serving as an oscillation damper for the hammer. The means for improving the repetition characteristics comprises an adjustable spring and linkage assembly attached at its ends to positions of substantially equal operating displacement on the wippen and the hammer butt. The spring and linkage assembly is adjusted such that, when the hammer is at its at-rest position and during movement of the hammer, wippen and jack to the point of escapement of the jack from beneath the hammer butt, the spring and linkage assembly is substantially unloaded. After escapement of the jack from beneath the hammer butt, relative movement of the wippen and hammer butt loads the spring and linkage assembly to render it capable of supporting the weight of the hammer, so that if the key is partially released and the hammer comes out of check the spring and linkage assembly will support the hammer in an intermediate position permitting the jack to return to its operating position beneath the hammer butt without full release of the key.