Music – Instruments – Electrical musical tone generation
Reexamination Certificate
2000-09-22
2002-04-02
Witkowski, Stanley J. (Department: 2837)
Music
Instruments
Electrical musical tone generation
C084S687000, C084S719000, C084S021000, C084SDIG007
Reexamination Certificate
active
06365820
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a keyboard assembly for electronic musical instruments, which is provided with mass members each driven as a corresponding key is depressed, and detecting means for detecting a state of key depression, the keyboard being associated with an electronic musical instrument such that the latter generates musical tones in accordance with the detected state of the key depression.
2. Prior Art
Japanese Laid-Open Patent Publication (Kohyo) No. 56-500055 discloses a keyboard assembly for electronic musical instruments, which is provided with mass members each driven as a corresponding key is depressed, and detecting means for detecting a state of key depression, the keyboard being associated with an electronic musical instrument such that the latter generates musical tones in accordance with the detected state of the key depression.
FIG. 15
is a side view showing a structure of a combination of a single key with an electronic signal output unit in the above conventional keyboard assembly.
As shown in the figure, a jack
202
is provided on a rear end of a key
201
to push a mass member
203
upward, and a spring arm
204
is fixed at one end thereof to a rear end of the mass member
203
, in a fashion extending from the rear end of the mass member
203
. The spring arm
204
has a roller
205
attached to the other end thereof. The roller
205
is urged against a switch plate
207
which has an upper pressure-sensitive layer
206
to be urged by the roller
205
.
When the key
201
is depressed, the mass member
203
is pushed upward by the jack
202
, whereby the roller
205
urgingly slides on the switch plate
207
downward until the mass member
203
comes into contact with an arm stopper
208
.
This conventional keyboard assembly is constructed such that key depression is not detected in regions close to the start and end points of a key stroke, because such regions are susceptible to erroneous touch and rebound, making the detection of key depressing operations unstable, but key depression is detected during a time period from a time point when the roller
205
reaches a first contact having a certain width and located at a substantially central portion of the switch plate
207
to a time point when the roller
205
reaches an initial end of a second contact having a certain width and also located at the substantially central portion of the switch plate
207
.
According to the conventional keyboard assembly, however, key depression is detected only within the region located at the substantially central portion of the switch plate
207
as described above. Thus, when a single key is successively depressed to repeatedly generate the same tone, it is necessary to provide a deeper key stroke than that of a keyboard assembly for an acoustic piano, and a player feels uncomfortable with such a deep key stroke.
Further, for the same reason, the convectional keyboard assembly is not capable of detecting such a key depression as to generate musical tones in a wide dynamic range.
If the region for detecting key depression is increased, it seems that the conventional keyboard assembly will have a key stroke during successive key depressions closer to that of a keyboard assembly for an acoustic piano so that it is possible to detect a key depression having a wide dynamic range.
However, in the conventional keyboard assembly, the region for detecting key depression is required to be limited as mentioned above for the following reasons: (1) when an initial end of the first contact is changed to a shallower position in the key stroke, a key depression starts to be detected even when the key
201
is slightly touched, and conversely, when the initial end of the second contact is changed to a deeper position in the key stroke, the detection of the key depression is not completed unless the key
201
is depressed to the full degree; and (2) when the key
201
is hit strongly, the mass member
203
collides with the arm stopper
208
to become stopped, but at this moment, a felt part of the arm stopper
208
collapses and then recovers, and if the key is then kept depressed, the felt part becomes slightly collapsed again, and this causes the roller
205
to move to and fro (i.e. rebound) on the switch plate
207
, and hence occurrence of chattering of the key due to rebound of the roller
205
must be suppressed.
Further, in the conventional keyboard assembly, the key depression/release operation timing and the tone generation/damping timing are slightly different from each other so that it is difficult to express delicacy as in acoustic pianos, particularly, grand piano.
SUMMARY OF THE INVENTION
It is a first object of the present invention to provide a keyboard assembly for an electronic musical instrument, which is capable of having touch inputs to a key from a finger of a player reflected in his power of expression with higher fidelity even when the single key is successively depressed to repeatedly generate the same tone.
It is a second object of the present invention to provide a keyboard assembly for an electronic musical instrument, which is capable of allowing the musical instrument to express delicacy as in acoustic pianos, particularly, grand piano.
To attain the first object, in a first aspect of the present invention, there is provided a keyboard assembly comprising a plurality of keys, a plurality of mass members each disposed to be pivotally driven in response to depression of a corresponding one of the plurality of keys, a support device that pivotally supports the plurality of keys and the mass members corresponding respectively to the keys, and a plurality of musical tone instruction devices that are provided respectively for the plurality of keys and each instruct generation and damping of a musical tone in response to depression of a corresponding one of the plurality of keys, wherein the musical tone instruction devices each comprise a first sensor and a second sensor for generating a key event during a stroke of the corresponding one of the keys in response to depression of the corresponding one of the keys or in response to pivotal movement of a corresponding one of the mass members responsive to the depression of the corresponding one of the keys, the first sensor being disposed to be activated in a first half of the stroke of the corresponding one of the keys to determine timing for damping of the musical tone, the second sensor being disposed to be activated in a second half of the stroke of the corresponding one of the keys to determine timing for generation of the musical tone, the second sensor further determining timing for determining a velocity of the corresponding one of the keys depending on a position of the corresponding one of the keys during the stroke relative to the support device.
The term “first half and second half of the key stroke” used herein does not mean a first half and a second half obtained by equally dividing the key stroke, but means more broadly, i.e. a first half and a second half obtained by dividing the key stroke at a desired ratio.
Further, the first and second sensors may be touch sensors or full-stroke sensors. When the full-stroke sensors are used, values detected during part of the full key stroke are used to determine the respective kinds of timing referred to above.
According to the arrangement of the first aspect, the first sensor which is activated in the first half of the key stroke determines the timing for damping a musical tone, and the second sensor which is activated in the second half of the key stroke determines not only the timing for generating a musical tone, but also the timing for determining the velocity of the corresponding one of said keys depending on the position of the corresponding key during the stroke relative to the support device. Therefore, to repeatedly generate the same tone, the key stroke need not extend to a position corresponding to the tone damping timing in the first half of the key stroke, but has only to extend to a po
Kondo Masao
Mishima Jun-ichi
Morrison & Foerster / LLP
Witkowski Stanley J.
Yamaha Corporation
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