Music – Instruments – Automatic
Reexamination Certificate
2001-05-31
2003-04-22
Donels, Jeffrey (Department: 2837)
Music
Instruments
Automatic
C084S019000, C335S255000
Reexamination Certificate
active
06552251
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a keyboard musical instrument and, more particularly, to a keyboard musical instrument for automatically playing a tune without fingering on the keyboard and a key actuating device incorporated therein.
DESCRIPTION OF THE RELATED ART
An automatic player piano is an example of the keyboard musical instrument for automatically playing a tune without fingering on the keyboard. The automatic player piano is usually broken down into an acoustic piano and an automatic playing system. A standard upright piano or a standard grand piano is used as the acoustic piano. A key actuating device and a controller are incorporated in the automatic playing system. Plural solenoid-operated key actuators are arrayed in two rows in a staggered fashion, and are assembled with a framework. The framework is fixed to the key bed of the acoustic piano, and the plural solenoid-operated key actuators are opposed to the rear portions of the black/white keys.
When a user instructs the controller to play a tune, the controller acquires a set of music data codes representative of the tune, and gets ready for an automatic performance. The controller is sequentially interpreting the music data codes of the set, and selectively energizes the solenoid-operated key actuators. When the solenoid-operated key actuators are energized, the solenoids generate magnetic fields, and the plungers project from the associated solenoids so as to push the rear portions of the associated black/white keys. Then, the key action mechanisms are actuated, and the hammers are driven for free rotation toward the associated strings. The hammers strike the associated strings at the ends of the free rotations. The strings vibrate, and generate the piano tones. Thus, the automatic playing system plays the tune on the keyboard without any fingering.
A typical example of the key actuator device is disclosed in Japanese Patent Publication of Unexamined Application No. 9-237082.
FIGS. 1 and 2
show the prior art automatic player piano equipped with the key actuating device. Reference numeral
100
designates a key actuating device. An acoustic piano has a key bed
101
, and a slot
102
is formed in the key bed
101
. A key frame is mounted on the key bed
101
, and plural black/white key
103
are rotatably supported by a balance rail (not shown) on the key frame. The black/white keys
103
form in combination a keyboard. The slot
102
is located under the rear portions of the black/white keys
103
, and is prolonged in the lateral direction of the key bed. The lateral length of the slot
102
is not shorter than the width of the keyboard, and the key actuating device
100
is opposed to the rear portion of the keyboard in the slot
102
.
The key actuating device
100
is broken down into a framework
110
and array of solenoid-operated key actuator units
120
. The solenoid-operated key actuator units
120
are respectively associated with the black/white keys, and are fixed to the framework
110
. The framework
110
is secured to the key bed
101
, and keeps the array of solenoid-operated key actuator units
120
in the slot
102
. The solenoid-operated key actuator units
120
are retained under the rear portions of the black/white keys
103
, and are respectively aligned with the rear portions.
The framework
110
is broken down into a base plate
111
, a center wall
112
and a bracket
113
. The bracket
113
is formed with a hole as long as the slot
102
, and is screwed to the lower surface of the key bed
101
so that the holes underlies the slot
102
. Holes are formed in the brackets at intervals. The base plate
111
has a land portion and a pair of fins. The land portion has a cross section like an inverted U-letter, and a slit is formed in the land portion. The fins outwardly project from the both sides of the land portion, and holes are formed in the fins at intervals. The land portion is as long as the slot
102
, and is narrower than the slot
102
. When the land portion is inserted into the slot
102
, the brackets
113
is underlain by the side fins, and the holes formed in the brackets
113
are aligned with the holes formed in the fins. Bolts are screwed into the holes so as to fix the base plate
111
to the bracket
113
. The bracket
113
keeps the upper surface of the land portion close to the lower surface of the key bed
101
.
The center wall
112
has a cross section like a mirror image of L-letter. The vertical portion of the center wall
112
passes through the slit, and the horizontal portion of the center wall
112
underlies the lower surface of the land portion. The horizontal portion of the center wall
112
is fixed to the land portion, and a rigid circuit board is hung from the horizontal portion of the center wall
112
. The vertical portion of the center wall
112
is upright on the land portion, and projects into the slot
102
. Though not shown in the figures, holes are formed in thee vertical portion at intervals, and are elongated in the vertical direction.
Each of the solenoid-operated key actuator unit
120
includes a yoke
121
, a solenoid
122
and a plunger
123
. The solenoid-operated key actuator units
120
are arranged in two rows, i.e., the front row and the back row. The yokes
121
of the solenoid-operated key actuator units
120
in the front row are fixed onto the front surface of the vertical portion by means of bolts
125
. The bolts
125
are inserted into the elongated hole, and are screwed into threaded holes formed the yoke
121
. The yokes
121
of the solenoid-operated key actuator units
120
in the back row are fixed to the back surface of the vertical portion in a staggered manner with the yokes on the front surface by means of the bolts
125
as shown in FIG.
2
. For this reason, even if the solenoid-operated key actuator units
120
have relatively large solenoids
122
, the yokes
121
permit the plungers
123
to be aligned with the relatively thin black/white keys
103
, respectively. The bolts
125
pass through the elongated holes, and are screwed into the threaded holes formed in the yoke
121
on the back surface of the vertical portion.
The yoke
121
is splitable into a lower plate and an upper plate, and a hollow space takes place between the lower plate and the upper plate. The solenoid
122
is accommodated in the hollow space, and is pinched therebetween. The solenoids
122
are connected to electric components arranged on the rigid circuit board. The plunger
123
is inserted into the solenoid, and is projectable from the solenoid
122
. The leading end of the plunger is in proximity of the lower surface of the associated black/white key
103
. When electric current flows through the solenoid
122
, magnetic field is created so that the plunger
123
projects upwardly. The upward motion of the plunger
123
gives rise to the rotation of the associated black/white key
103
around the balance rail.
The solenoid-operated key actuator units
120
are assembled with the center plate
112
as follows. First, the center wall
112
is assembled with the base plate
111
. Subsequently, the yoke
121
is moved on one of the front/back surfaces of the vertical portion, and the threaded holes of the yoke
121
are roughly aligned with the elongated holes of the vertical portion. The yoke
121
is vertically moved along the elongated holes so as to place the leading end of the plunger
123
at the appropriate position close to the lower surface of the rear portion of the associated black/white key
103
. The bolt holes of the yoke
121
are strictly aligned with the elongated holes of the vertical portion without changing the gap between the plunger
123
and the associated black/white key
103
, and the bolts
125
are inserted from the other of the front/back surfaces through the elongated holes into the threaded holes. The bolts
125
are screwed into the threaded holes, and presses the yoke
121
against the front/back surface.
Subsequently, the yoke
121
is moved to the other of the front/back surfaces of the v
Muramatsu Shigeru
Okabe Syuzo
Donels Jeffrey
Morrison & Foerster / LLP
Yamaha Corporation
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