Music – Instruments – Stringed
Reexamination Certificate
2000-01-21
2001-07-24
Donels, Jeffrey (Department: 2837)
Music
Instruments
Stringed
C084S220000
Reexamination Certificate
active
06265647
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a keyboard musical instrument and, more particularly, to a keyboard musical instrument equipped with a hammer stopper.
DESCRIPTION OF THE RELATED ART
The keyboard musical instrument is broken down into an acoustic piano, an electronic sound generating system and a silent system. The silent system has the hammer stopper, which is changed between a free position and a blocking position. While the hammer stopper is staying in the free position, the hammers selectively strike the sets of strings without any interference, and the strings vibrate for generating acoustic sounds. When the hammer stopper is changed to the blocking position, the hammer stopper is positioned on the trajectories of the hammers. A depressed key actuates the associated key action mechanism, and the hammer is driven for free rotation by the key action mechanism. Although the hammer is moved along the trajectory, the hammer rebounds on the hammer stopper without striking the set of strings. For this reason, any acoustic sound is generated. However, the electronic sound generating system detects the key motion, and a headphone generates an electronic sound instead of the acoustic sound. The electronic sound generating system can records a performance on the keyboard in the form of digital data codes.
The hammer stopper laterally extends in the space between the hammer shanks and the sets of strings, and the hammer shanks rebound on the hammer stopper. For this reason, this kind of hammer stopper is called as “shank stopper”. A link mechanism is connected to the shank stopper, and a wire interconnects the link mechanism and a knob. A player manipulates the knob so as to change the shank stopper between the free position and the blocking position.
The prior art link mechanism has two parallel links. Both parallel links are spaced from each other, and are turnably connected to a stationary member. The shank stopper is attached to the other ends of the parallel links, and the links, the stationary member and the shank stopper form in combination a parallel crank. The wire is connected to one of the links, and gives rise to a parallel motion. The parallel crank changes the distance between the shank stopper and the stationary member through the parallel motion. A position close to the stationary member and another position spaced from the stationary member are corresponding to the two positions of the shank stopper. The parallel links vertically project from the stationary member, and the shank stopper is changed in the vertical direction.
The first problem inherent in the prior art silent system is torsion of the shank stopper. This is because of the fact that the shank stopper is shared between all the hammer shanks. A standard acoustic piano has eighty-eight keys and, accordingly, eighty-eight hammers. The eighty-eight hammers are laterally arranged, and the distance between the leftmost hammer and the rightmost hammer is long. The shank stopper is opposed to the hammer shanks of all the hammers, and is also long. As described hereinbefore, the wire is connected to one of the links, and the motion of the link is transferred through the shank stopper to the other link. In this situation, when the wire is pulled, the link connected thereto gives rise to the parallel motion. However, the shank stopper is not rigid, but is deformable. The turning motion of the link is causative of the torsion, and the other end portion of the shank stopper does not enter the blocking position. This results in undesirable acoustic sounds. If plural wires are connected to the shank stopper at intervals, the shank stopper may be free from the torsion. However, the silent system is complicated, and increases the production cost of the prior art keyboard musical instrument.
The unintentional change to the free position is the second problem inherent in the prior art silent system. The second problem is also derived from the long shank stopper. The hammer shanks rebound on the shank stopper. The impact is strong, and causes the shank stopper to be unintentionally changed to the free position. This results in undesirable acoustic sounds. Thus, the prior art silent system is not reliable.
A spring is used in another prior art silent system so as to move the hammer stopper in the vertical direction, and yet another shank stopper is changed between the free position and the blocking position through bi-directional rotation. However, the first problem and/or the second problem is encountered in those prior art silent systems.
SUMMARY OF THE INVENTION
It is therefore an important object of the present invention to provide a keyboard musical instrument, a silent system of which is simple and reliable.
To accomplish the object, the present invention proposes to move a hammer stopper between a free position and a blocking position through a horizontal motion.
In accordance with one aspect of the present invention, there is provided a keyboard musical instrument having a lateral direction and a fore-and-aft direction perpendicular to the lateral direction comprising a keyboard having plural keys arranged in the lateral direction and assigned notes of a scale, respectively, plural music strings for generating acoustic tones of the notes, respectively, plural hammers respectively linked with the plural keys for striking the plural music strings, respectively and a silent system including a hammer stopper selectively entering a free position where the plural hammers are allowed to strike the associated music strings and a blocking position where the hammers rebound thereon before striking the associated music strings and a change-over means connected to the hammer stopper so as to change the hammer stopper between the free position and the blocking position, and the hammer stopper includes two members spaced apart from one another in the lateral direction and respectively having vertical axes of rotation at first end portions thereof, absorbing means where the hammers rebound. and a movable member supporting the absorbing means and connected to second end portions of the two members spaced from the first end portions so that the change-over means gives rise to a rotation of the movable member around the axes of rotation.
REFERENCES:
patent: 5565636 (1996-10-01), Sugiyama
patent: 5583306 (1996-12-01), Hayashida et al.
patent: 5600077 (1997-02-01), Honda
patent: 5616880 (1997-04-01), Hayashida et al.
patent: 5741995 (1998-04-01), Kawamura et al.
patent: 5949013 (1999-09-01), Satoshi
patent: 7-230279 (1995-08-01), None
patent: 8-63149 (1996-03-01), None
patent: 10-149154 (1998-06-01), None
Itou Katsuo
Tamaki Takashi
Donels Jeffrey
Morrison & Foerster
Yamaha Corporation
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