# US 7,408,102 B2 · Jack motion-restricting device for upright piano

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- Number: US 7,408,102 B2
- Document ID: US7408102B2
- Status: Granted
- Kind: B2
- Application number: 11/702,354
- Filed: 2007-02-05
- Published: 2007-08-09
- Granted: 2008-08-05
- Earliest claimed: 2006-02-09
- Assignees: Kabushiki Kaisha Kawai Gakki Seisakusho
- Inventors: Hidenori Kugimoto
- Web page: https://patentgrep.com/patent/US7408102B2

## CPC

- G10C 1/02: of upright pianos
- G10C 3/161: specially adapted for upright pianos
- G10C 9/00: Methods, tools or materials specially adapted for the manufacture or maintenance of musical instruments covered by this subclass
- G10C: PIANOS, HARPSICHORDS, SPINETS OR SIMILAR STRINGED MUSICAL INSTRUMENTS WITH ONE OR MORE KEYBOARDS (automatic musical instruments G10F)

## 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.

## Claims

### Claim 1

A jack motion-restricting device for an upright piano, which restricts motion of a jack operating in accordance with key depression, by having the jack abut thereagainst, comprising:
a rigid base part that is provided at a location close to the jack;
a base layer that is formed of a resilient material having dimensional stability to absorb the impact of the jack abutting the device, and is affixed to said base part; and
a surface layer that is formed of a material having abrasion resistance and flexibility, and is affixed to said base layer, for having the jack abut thereagainst.

### Claim 2 (depends on 1)

A jack motion-restricting device as claimed in claim 1, wherein said base part is formed of a chemical fiber.

### Claim 3 (depends on 1)

A jack motion-restricting device as claimed in claim 1, wherein said surface layer is formed of a fluoropolymer fiber.

### Claim 4 (depends on 1)

A jack motion-restricting device as claimed in claim 1, wherein the jack motion-restricting device is a butt against which the jack performing a return pivotal motion in accordance with key realease abuts to thereby define a stationary position of the jack in a key-released state.

### Claim 5 (depends on 1)

A jack motion-restricted device as claimed in claim 1, wherein the jack motion-restricting device is a regulating button against which the jack moving upward in accordance with key depression abuts to thereby cause the jack to perform a pivotal motion to cause let-off to occur.