Music – Instruments – General features
Reexamination Certificate
1998-02-20
2002-04-09
Hsieh, Shih-Yung (Department: 2837)
Music
Instruments
General features
C084S433000, C084S434000, C084S435000, C084S436000
Reexamination Certificate
active
06369309
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a keyboard assembly, and more particularly to a keyboard assembly which is improved in the facility of assemblage thereof.
2. Prior Art
Conventionally, a keyboard assembly used in musical instruments operated by using a keyboard, such as an electronic piano, is assembled by separately fabricating keys and a key support member such as a key frame, and then mounting the keys on the key support member. In general, the key support member of the keyboard assembly has key depression-detecting means, such as key switches, mounted thereon for detecting depression of the respective keys. The key depression-detecting means have resilient expanded portions made e.g. of rubber. Each key has an actuator formed thereon for depressing a corresponding one of the resilient expanded portions when it is depressed or operated by the player, and when the depression of the key is detected by the key depression-detecting means, a key-on signal is generated.
To ensure proper functioning of the key depression-detecting means, each key is required to be mounted at a location at which the actuator of the key is properly brought into abutment with the resilient expanded portion. To this end, a conventional keyboard assembly has been proposed by Japanese Laid-Open Patent Publication (Kokai) No. 6-110450, which includes a guide member provided on the bottom of a common rear end portion of each key, which serves not only as positioning means but also as guiding means for guiding the key when it is mounted, and a hole corresponding to the guide member, which is formed in a key support member. The guide member is inserted into the hole for positioning the key, and then the common rear end portion of the key is fixed to the key support member by a screw or the like.
Another conventional keyboard assembly proposed by the above-mentioned Japanese Laid-Open Patent Publication (Kokai) No. 6-318076 includes a single dowel pin provided on each key unit in a fashion protruding from the bottom of a common rear end portion of keys, a hole formed in a key support member for receiving the dowel pin, and a projection formed on the key support member, for abutment with a rear end of the common rear end portion of the keys. The dowel pin holds the key unit at one contact point, and the projection prevents the key unit from undergoing a slight horizontal pivotal motion about the dowel pin, to thereby hold the key unit (and hence keys) in position. Further, finally, the common rear end portion of the keys is fixed to the key support member by screws.
Normally, the key depression-detecting means, the key support member, and the keys are fabricated separately. Therefore, improper contact or abutment of each actuator on the corresponding resilient expanded portion can be caused not only by manufacturing tolerances of the component parts but also by positioning or alignment errors therebetween (mounting errors). Further, when a plurality of key units are mounted on the body of the keyboard assembly, one key unit can suffer from similar inconveniences ascribable to tolerances or mounting errors of component parts of another key unit.
Even if there are such tolerances or mounting errors, so long as the bottom of each actuator is flat in shape and has a sufficient longitudinal length, an error in the longitudinal position of the key can be accommodated to some extent whereby it is possible to bring the actuator into contact with the resilient expanded portion to a proper extent. However, an error in the lateral position of each key can be accommodated only to a very slight extent due to a limited width thereof. If such an error cannot be accommodated or compensated for, the key (or key unit) is regarded as defective, and the mounting of a key (or key unit) has to be carried out again, resulting in not only degraded productivity but also a lowered yield of keys, which leads to an increase in the manufacturing cost.
FIG. 1
shows an outline of the construction of a conventional keyboard assembly, which is in a pre-assembled state.
In the conventional keyboard assembly, keys are preassembled into key units
91
, each formed as a laminate of white keys and black keys, and mounted on a key support member
92
. The mechanism of the keyboard assembly imposes various requirements on the manner of mounting the key units
91
on the key support member
92
.
First, a key switch
93
as key depression-detecting means operates to detect depression of a key corresponding thereto by sensing an urging force of the key acting thereon. Therefore, after the key unit
91
has been mounted on the key support member
92
, when a key is in a released state, normally, an actuator
94
formed on the key lightly contacts the resilient expanded portion of the key switch
93
. On the other hand, during the mounting process of the key unit
91
on the key support member
92
, to prevent the actuator
94
from applying a horizontal external force to the resilient expanded portion, which leads to peeling and deformation of the resilient expanded portion, it is desirable that the actuator
94
abuts or urges the resilient expanded portion vertically or from right above. Although peeling and deformation of the resilient expanded portion can be prevented by increasing the hardness thereof, this degrades a key touch sensed when the key is depressed. Therefore, the actuator
94
and the resilient expanded portion are required to be kept out of contact from each other up to a stage immediately before the mounting process of the key unit
91
is finished when the key unit is no longer moved horizontally.
For example, in the conventional keyboard assembly, each key
91
has a guide projection
96
formed on the bottom of a rear end portion (common rear end portion
95
) thereof, and at the same time, the key support member
92
has a hole
97
formed therein for having the guide projection
96
fitted therein when the key unit
91
has been mounted, whereby the rear half of each key is supported by the guide projection
96
up to a stage immediately before the mounting of the key unit
91
is completed. Further, during the mounting process of the key unit
91
, the front half of each key is supported by the top of a key guide
98
(provided for preventing a transverse sway or twist of the key when it is depressed). Other examples are disclosed in Japanese Laid-Open Patent Publications (Kokai) Nos. 6-318076 and 8-123419, in which a guide member for supporting the rear half of each key is provided not on the key unit
91
but on the key support member
92
for the ease of handling of the key before mounting of the key unit.
Further, a plurality of guide members for assisting the mounting operation of the key unit
91
, such as the guide projection
96
, are normally provided. However, these members should not interfere with key depressing operations by the operator or player. In the conventional keyboard assembly, after the key unit
91
has been mounted, the guide projection
96
are fitted in the holes
97
to thereby prevent the guide projection from interfering with key-depressing operations by the user.
Further, it is necessary to provide a so-called upper limit stopper for setting an upper limit position of a front end (operator side-end) of each key when the key is a released state after the mounting of the key unit
91
. For example, in the conventional keyboard assembly, each key is integrally formed with a follower portion
99
which is slidably guided by the key guide
98
, and the follower portion
99
has an engaging end
99
a
formed integrally at a lower end thereof for abutting on a stopper, not shown, provided at a location close to a lower end of the key guide
98
when the depressed key returns to its original released position.
Furthermore, to facilitate accurate mounting operations of keys, means for controlling the position of each key in a lateral direction, i.e. in a direction in which keys are juxtaposed is indispensable. In the conventional keyboard assembly, for exam
Hsieh Shih-Yung
Morrison & Foerster / LLP
Yamaha Corporation
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