Abstract: A jack motion-restricting device for an upright piano, which is capable of maintaining constant a jack motion-restricting position by a simple construction to thereby obtain an intended operation of the jack. The jack motion-restricting device restricts the motion of the jack operating in accordance with key depression by having the jack abut thereagainst. A base part of the device is provided at a location close to the jack. A base layer of the same is formed of a material having dimensional stability, and is affixed to the base part. A surface layer of the same is formed of a material having abrasion resistance and flexibility, and is affixed to the base layer, for having the jack abut thereagainst.

Abstract: A jack motion-restricting device for an upright piano, which is capable of maintaining constant a jack motion-restricting position by a simple construction to thereby obtain an intended operation of the jack. The jack motion-restricting device restricts the motion of the jack operating in accordance with key depression by having the jack abut thereagainst. A base part of the device is provided at a location close to the jack. A base layer of the same is formed of a material having dimensional stability, and is affixed to the base part. A surface layer of the same is formed of a material having abrasion resistance and flexibility, and is affixed to the base layer, for having the jack abut thereagainst.

Abstract: A key for a musical instrument is provided for facilitating the attachment of a weight, and adjustments of a touch load, while using an alternative material for substitution for lead as a material for the weight. The key comprises a swingable key body formed with embedding holes, and weights each made of a material other than lead and having a threaded outer peripheral surface. The weight is screwed into the embedding hole for removable fit into the key body to give a load to the key body. A plurality of types of weights different in load from one another are provided for selecting one having an appropriate load therefrom to adjust the touch load.

Abstract: A key for a musical instrument is provided for facilitating the attachment of a weight, and adjustments of a touch load, while using an alternative material for substitution for lead as a material for the weight. The key comprises a swingable key body formed with embedding holes, and weights each made of a material other than lead and having a threaded outer peripheral surface. The weight is screwed into the embedding hole for removable fit into the key body to give a load to the key body. A plurality of types of weights different in load from one another are provided for selecting one having an appropriate load therefrom to adjust the touch load.

Abstract: A tuning apparatus for a keyboard musical instrument, having a load applicator for applying a load of a predetermined value to a string set up in place, a calculating device for calculating a deviation between a displacement value of the string produced when the load is applied to the string and a preset value of displacement predetermined to give a required frequency of vibration, and a rotating device for turning a tuning pin until the deviation calculated by the calculating device is reduced to zero.