Music – Instruments – Electrical musical tone generation
Reexamination Certificate
2001-11-14
2003-02-04
Fletcher, Marlon T. (Department: 2837)
Music
Instruments
Electrical musical tone generation
C084S236000, C084S423001, C084S600000, C084S719000
Reexamination Certificate
active
06515213
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a keyboard musical instrument and, more particularly, to a keyboard musical instrument equipped with hammers such as, for example, an automatic player piano and a silent piano and a hammer sensor used therein.
DESCRIPTION OF THE RELATED ART
The automatic player piano is a composite keyboard musical instrument fabricated on the basis of an acoustic piano. An array of solenoid-operated key actuators and an array of key sensors are provided in association with the keyboard, and an electronic controlling system is connected to the array of solenoid-operated key actuators and the array of key sensors. While a pianist is playing a tune on the keyboard, the black and white keys are selectively depressed by the pianist, and the associated key sensors report the key motion to the electronic controlling system. The electronic controlling system specifies the depressed black/white keys and the released black/white keys, and determines the lapse of time at which the black/white keys are depressed and released. Moreover, the electronic controlling system calculates the key velocity. These pieces of music data information are stored in a set of music data codes for playback.
When a user instructs the electronic controlling system to reproduce the performance, the electronic controlling system reads out the pieces of music data information. The electronic controlling system supplies driving signals to the solenoid-operated key actuators at the same timing as in the original performance, and the solenoid- operated key actuators move the associated black/white keys without any fingering on the keyboard. Thus, the automatic player piano records the original performance, and reproduces the original performance without any fingering on the keyboard.
The silent piano is another composite keyboard musical instrument. An array of key sensors is provided in association with the keyboard, and an electronic tone generating system is connected to the array of key sensors. A hammer stopper is changeable between a free position and a blocking position. When the hammer stopper is changed to the free position, the hammer stopper is moved out of the trajectories of the hammers. The pianist selectively strikes the music strings with the hammers through the fingering on the keyboard, and the acoustic piano tones are generated from the vibrating music strings. If the pianist changes the hammer stopper to the blocking position, the hammer stopper is moved into the trajectories of the hammers. Even though the pianist fingers a tune on the keyboard, the hammers rebound on the hammer stopper before striking the music strings, and any acoustic piano tone is not generated from the music strings. However, the key sensors monitor the associated black/white keys, and report the key motion to the electronic tone generating system. The electronic tone generating system specifies the depressed black/white keys and the released black/white keys, and determines the key velocity. The electronic tone generating system produces an electric signal representative of the tones to be generated, and electronic tones are produced by a sound system.
Thus, the key sensors are indispensable in both automatic player and silent pianos. When a pianist simply depresses the black/white keys from the rest positions to the end positions, the key sensors exactly report the key motion to the electronic controlling/electronic tone generating system, and the reproduced tone/electronic tone is fairly equivalent to the original tone, because the associated hammer is driven for rotation at a hammer velocity proportional to the key velocity. However, the performance is usually not constituted by the simple key motion. A black/white key may be repeatedly depressed by the pianist, and another black/white key may return on the way to the end position. In this situation, the key motion does not give rise to the hammer motion at a hammer velocity proportional to the key motion. As a result, the reproduced tone/electronic tone is generated at loudness different from the original piano tone/the piano tone to be generated. Thus, the key sensors hardly respond to the complicated key motion.
In order to exactly determine the hammer motion, it has been proposed directly to detect the hammer motion. An array of hammer sensors is installed inside the piano case. The hammer sensors directly monitor the associated hammers, and report the current positions of the associated hammers. With the pieces of positional information, the electronic controlling system/electronic tone generating system exactly determines the hammer motion, and stores the pieces of music data information in the music data codes.
There are several kinds of hammer sensors which have been already known. The first kind of hammer sensor is a combination of a shutter plate and a photo-coupler. The shutter plate is formed with a window. Otherwise, the photo-coupler produces plural light beams. The shutter plate is assumed to have the window. The shutter plate is fixed to the hammer shank, and, accordingly, is movable together with the hammer assembly. The photo-coupler is, by way of example, supported by the action brackets, and produces the light beam across the trajectory of the shutter plate. When the associated black and white key is depressed, the action mechanism drives the hammer assembly for rotation, and the shutter plate is moved along the trajectory. When the shutter plate reaches the light beam, the shutter plate intercepts the light beam. The shutter plate continuously intercepting the light beam until the window reaches. The shutter plate permits the light beam to pass the window, and intercepts the light beam, again. The electronic controlling system/electronic tone generating system calculates the hammer velocity on the basis of the lapse of time between the interception at the front and the passage through the window. The shutter plate is appropriately designed so that the electronic controlling system/electronic tone generating system determines the timing at which the hammer strikes the string.
The second kind of the hammer sensor is shown in
FIG. 1
, and is a combination of a reflecting photo-coupler
500
and a reflecting sheet
502
. The reflecting photo-coupler
500
is fixed to a stationary bracket
500
, and radiates a light beam toward a hammer assembly
503
. On the other hand, the reflecting sheet
502
is attached to the hammer shank
504
, and is moved together with hammer assembly
503
along the trajectory of the hammer shank
504
. The light beam is always reflected on the reflecting sheet
502
, and returns to the reflecting photo-coupler
500
. The amount of reflected light is varied depending upon the current hammer position, and the reflecting photo-coupler
500
reports the amount of reflected light to the electronic controlling system/electronic tone generating system. The electronic controlling system/electronic tone generating system determines the current hammer position, and calculates the hammer velocity. The electronic controlling system/electronic tone generating system determines the time at which the hammer strikes the music string
505
when the amount of reflected light reaches a predetermined value.
The third kind of hammer sensor is a combination of a Hall-effect element and a permanent magnet piece. The reflecting photo-coupler
500
is replaced with the Hall-effect element, and the piece of permanent magnet piece is attached to the hammer shank
504
. The magnetic field strength is varied together with the distance between the Hall-effect element and the permanent magnet piece, and the Hall-effect element generates the electric current in the magnetic field created by the permanent magnetic piece. The amount of current is representative of the magnetic field strength and, accordingly, the distance between the Hall-effect element and the permanent magnetic piece. The electronic controlling system/electronic tone generating system determines the current hammer position on the basis of the amount of el
Kato Tadaharu
Muramatsu Shigeru
Sasaki Tsutomu
Fletcher Marlon T.
Morrison & Foerster / LLP
Yamaha Corporation
LandOfFree
Keyboard musical instrument for exactly producing tones and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Keyboard musical instrument for exactly producing tones and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Keyboard musical instrument for exactly producing tones and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3168713