Piano keyboard device including improved support chassis and optional action simulation mechanism, and a method of assembling thereof

A plate-like member or rib 19 is extended in a back-to-front direction of a key 14. The height of a rear end of a flat portion 12 is regulated by an upper flange portion 21c and a lower flange portion 22 of the rib 19. A wippen 30 provided with a jack 44 is attached via a bearing member 33 for supporting a wippen swing axis 31 onto a chassis 11. A hammer 50 is attached via a center rail 60 provided with a bearing member 65 for supporting a hammer swing axis 51 onto the chassis 11. A bearing 16 for supporting a key support 15 is fixed to the chassis 11 with a flange portion 61 of the center rail 60 abutting on a rear L-shaped leg 18. A substantially L-shaped rail 67 is fixed with a screw on the center rail 60, which has on its top face a hammer cushion 68 for abutting a rest portion 52 of the hammer 50 and on its lower face a regulating felt for abutting on a hack tail 47. The wippen 30 has a long swing radius, and therefore a larger inertial moment by a weight 41, as compared with the jack 44 and the hammer 50. The rest portion 52, a butt portion 53 and a catcher portion 54 are provided on a continuous face of the hammer 50. A cushion material 56 constituted of a urethane foam layer for absorbing impact and an artificial leather layer providing slidability is placed on the continuous face. The key support 15 is provided between a sliding tape 32 of the wippen 30 and a jack axis 45.

BACKGROUND OF THE INVENTION 
The present invention relates to a keyboard device of an acoustic piano, an 
electronic piano or another keyboard instrument and an assembly method 
thereof, and particularly to though not exclusively a keyboard device 
provided with an action mechanism or a simulating action mechanism 
disposed on a chassis with a key support as a key swinging center disposed 
on a key bed and constituted of a wippen, a jack and a hammer, or to a 
keyboard device provided with a key support member including a key swing 
center and a rail member having a hammer swung in accordance with swinging 
of a key, both members being fixed on a chassis. 
In a keyboard device heretofore used in an electronic piano, for example, 
as shown in FIG. 5, to secure a space of a key 514 (white key shown in 
FIG. 5) when depressed, a chassis 511 is provided with a flat portion 512 
higher than a top face of a key bed 502. The flat portion 512 is provided 
with a key support 515, centering on which the key 514 is vertically 
swingably supported. Since the depressed key 514 is biased 
counterclockwise as shown in FIG. 5 by a spring 516 interconnecting a rear 
end of the key 514 and a rear end of the chassis 511, the key 514 returns 
to its original position when released. 
Also, a base 528 is attached slightly lower than the chassis 511, and has 
thereon a push button 537 for detecting depression of the key 514. Two 
switches are disposed inside the push button 537: when the key 514 is 
depressed, at the initial stage one of the switches is depressed by an 
actuator 535 provided under the key 514, and when the key 514 is further 
depressed, the other switch is also depressed by the actuator 535. Key 
depressing timing and velocity can be obtained from a difference in 
switching on or off timing between the two switches. 
In the keyboard device, the flat portion 512 of the chassis 511 is extended 
in a key arrangement direction (vertical to FIG. 5) and in a key 
back-to-forth direction (right to left in FIG. 5). The key support 515 of 
each of all the keys (e.g. 88 keys) is provided on the flat portion 512. 
A rear end of the flat portion 512 of the chassis 511 is bent vertically 
downward via a first bent portion 511a, and further bent forward (or 
backward) via a second bent portion 511b. Therefore, the height of the 
rear end of the flat portion 512 is defined by the first and second bent 
portions 511a and 511b. A front end of the flat portion 512 of the chassis 
511 is provided with a substantially U-shaped leg portion 513, which 
defines the height of the front end of the flat portion 512. The flat 
portion 512 of the chassis 511 is further provided with a reinforcing rib 
519. The rib 519 is a leaf member extending in the key back-to-forth 
direction, and is provided with contact faces 519a, 519b for contacting an 
underside of the flat portion 512 of the chassis 511 and a reinforcing 
flange 519c. 
In the aforementioned keyboard device, however, the accuracy in height of 
the key support 515 is influenced by the ending accuracy (accuracy in 
angle or in dimension of the height) of the first and second bent portions 
511a and 511b of the chassis 511. The dimension (area) of the chassis 511 
is so large that a large-sized metallic mold is necessary for bending the 
chassis 511 with a press or the like, and it is difficult to obtain a high 
accuracy. 
On the other hand, for example in a keyboard device for use as an 
electronic keyboard instrument as shown in FIG. 6, to obtain the same key 
touch as in an acoustic piano, a simulating action mechanism is provided. 
Specifically, a hammer 650 is provided behind a rear end of a flat portion 
612 of a chassis 611. An action lever 605 for transmitting action to the 
hammer 650 is passed from the underside of the key backward through a hole 
606 connecting a rear end of the chassis 611 and a key bed 602, to 
transmit action of the key via a wippen 630, a jack 644 and a butt 649 to 
the hammer 650. 
In the aforementioned keyboard device, a raised portion of the chassis 611 
between a first bent portion 611a and a second bent portion 611b, the hole 
606 for passing the action lever 605 needs to be provided. Further, the 
hole 606 is required for each hammer, thereby increasing cost. Also, the 
accuracy in height of a key support is influenced by the bending accuracy 
of the first and second bent portions 611a and 611b in the same manner as 
the keyboard device of FIG. 5. Therefore, it is not easy to obtain a high 
accuracy. 
As a keyboard heretofore used in an electronic instrument, a wooden 
keyboard provided with a hammer or a plastic keyboard provided with a 
hammer is known. In this keyboard, the hammer is swung directly by a 
corresponding key. Therefore, a key letting-off effect cannot be obtained. 
There exists a problem that a touch of an acoustic piano cannot be 
realized. 
To solve the problem and realize the touch of an acoustic piano, as shown 
in FIGS. 6, 8 or 16, an electronic instrument keyboard provided with a 
simulating action mechanism has been developed. 
In the keyboard device shown in FIG. 6, when a key 614 is depressed to 
swing counterclockwise in the figure, an action lever 670 provided under 
the key 614 is also swung counterclockwise centering on a lever swing axis 
671 on the chassis 611. Accompanying the swinging, the wippen 630 is swung 
clockwise arround a wippen swing axis 631 provided on a center rail 660, 
and the jack 644 pushes up the butt 649 of the simulating hammer 650. The 
simulating hammer 650 is then swung clockwise. After a jack tail 647 abuts 
on a regulating button 666, the jack 644 is rapidly swung counterclockwise 
to be disengaged from the butt 649. Then, the hammer 650 starts its 
inertial movement. This timing is a letting-off timing. Upon contact with 
a stopper 663, the hammer 650 swings back. In this manner, the keyboard 
device shown in FIG. 6 realizes a touch of an upright piano. 
The key support 615 as a swing center of the key 614 is supported by a 
bearing 616 serving as a key support member. As shown in a partially 
enlarged view of FIG. 11, the bearing 616 has substantially L-shaped legs 
618 thereunder. In attachment, after the L-shaped legs 618 are passed 
through inlets 617 in the chassis 611, the bearing 616 is slid toward the 
front of the key (to the left in FIG. 11). Thereby, the chassis 611 is 
placed between the L-shaped legs 618 and the underside of the bearing 616. 
Under this condition, a stopper piece 620 is fixed with a screw to abut on 
the rear end of the L-shaped legs 618. In this manner, the bearing 616 is 
fixed immobile on the chassis 611. 
However, in this keyboard device, the stopper piece 620 is provided only 
for the bearing 616, which adds to cost. Also, attachment of the stopper 
piece 620 is additionally required, making complicated the operation. 
Further, when the key 614 needs to be replaced, by removing the screw from 
the stopper piece 620, the stopper piece 620 has to be once removed. 
In another keyboard device shown in FIG. 8, an action mechanism is the same 
as the action mechanism of an upright piano, except that a stopper is 
provided instead of a string. In the keyboard device, when depressed, a 
key 814 is swung counterclockwise centering on a key support 815. 
Accordingly, a wippen 830 is swung clockwise centering on a wippen swing 
axis 831 provided on a center rail 860, a jack 844 pushes up a butt 850a 
of a hammer 850, and the hammer 850 is then swung clockwise centering on a 
hammer swing axis 851 provided on the center rail 860. After a tail jack 
847 abuts on a regulating button 866, the jack 844 is rapidly swung 
counterclockwise to be disengaged from the butt 850a. The hammer 850 in 
turn starts its inertial movement. This timing is a letting-off timing. 
Upon contact on a stopper 863, the hammer 850 sings back. In this way, the 
keyboard device of FIG. 8 realizes a touch of an upright piano. 
However, a regulating felt on the regulating button 866 for regulating 
operation of the jack 844 is provided separately from a hammer cushion 868 
for regulating an initial position of the hammer 850. Specifically, the 
former is provided on a regulating rail 861 fixed to the hammer rail 860, 
and the latter is provided on the hammer rail 869. Therefore, two separate 
members, the regulating rail 861 and the hammer rail 869 are necessary, 
thereby increasing cost remarkably. 
On the other hand, to adjust the letting-off timing to a predetermined 
timing, the attachment accuracy of the regulating rail 861 provided with 
the regulating felt on the regulating button 866 needs to be increased. To 
set the initial position of the hammer 850 at a predetermined position, 
the attachment accuracy of the hammer rail 869 provided with the hammer 
cushion 868 needs to be increased. Therefore, the attachment accuracy of 
the two different members needs to be increased. 
Also in the keyboard devices shown in FIGS. 6 and 8, a key unit U1 is 
provided separately from an action unit U2. Therefore, when the key unit 
U1 and the action unit U2 are assembled on the key bed, it is difficult to 
position these units U1 and U2. Also, after the units are attached onto 
the key bed, the height of the wippen needs to be adjusted with a capstan 
screw S for adjusting a key stroke. 
In a keyboard device 701 for an electronic keyboard instrument provided 
with a simulating action mechanism shown in FIG. 16, a button type sensor 
737 is provided under a key 714. The sensor 737 is provided with two 
switches inside. When the key 714 is depressed, one of the switches is 
depressed to issue an on signal, and when the key 714 is further 
depressed, the other switch is depressed to issue an on signal. 
Specifically, the sensor 737 detects respective timings at which the key 
714 passes two predetermined positions while the key 714 moves from an 
initial position to a full stroke position. Based on the signals 
transmitted from the two switches of the sensor 737, a control device 705 
obtains string striking information for producing string striking sound 
and sound stop information for stopping sound. Specifically, a velocity is 
obtained as sound intensity from a difference in on-timing between the 
switches, and sounding is stopped based on the off-timing of the switches. 
In the keyboard device 701 for an electronic keyboard instrument, in the 
same manner as an acoustic piano, the key 714 abuts on a wippen 730 via a 
cushion C1, and a jack 744 abuts on a butt 750a of a hammer 750 via a 
cushion C2. Therefore, when the key 714 is depressed at a high speed, 
these cushions C1 and C2 is once resiliently deformed to store a certain 
degree of force. Thereafter, when the cushions C1 and C2 recover 
themselves, the wippen 730 and the hammer 750 act, thereby producing a 
strong piano sound. After the key 714 is depressed, there is a time lag 
before sound is produced. These characteristics are unique to an acoustic 
piano. 
However, in the constitution where the key 714 pushes against the button 
type sensor 737, when the key 714 is rapidly depressed, the cushions C1, 
C2 are resiliently deformed from when one of the switches inside the 
sensor 737 is turned on until the other switch is turned on to resist 
pressure, which produces a resistance force. Therefore, a difference in 
on-timing between the switches becomes large, and a detected velocity 
(corresponding to the movement speed of the key) is decreased. An 
electronic sound is produced with intensity in accordance with the 
velocity. No strong sound is disadvantageously produced like an acoustic 
piano. Also, there arises no time lag until sound is produced like an 
acoustic piano. Specifically, in the keyboard device 701, the 
aforementioned characteristics peculiar to an acoustic piano cannot be 
reproduced precisely. 
Therefore, there exists a desire for development of a keyboard device for 
an electronic piano which can reproduce the characteristics peculiar to an 
acoustic piano. 
It is proposed in the keyboard device 701 that the generation of electronic 
sound is controlled in accordance with the movement speed of the hammer 
750, not the movement speed of the key 714. The hammer 750 has the largest 
inertial moment in the swingable members of the action mechanism. After 
the key 714 is depressed, the hammer 750 most remarkably withstands before 
starting swinging. Therefore, by generating an electronic sound in 
accordance with the movement speed of the hammer 750, the aforementioned 
characteristics peculiar to an acoustic piano can be remarkably precisely 
reproduced. Specifically, for example, a sensor, the same as the button 
type sensor 737, to be depressed by the hammer 750 is provided for 
detecting the hammer 750 at two places between a standstill position and a 
simulating string-striking position of the hammer 750. 
In the keyboard device 701, in the same manner as an acoustic piano, when 
the key 714 is depressed from its standstill position to its full-stroke 
position, the hammer 750 is swung from the standstill position (shown by a 
solid line in FIG. 16), midway let off and swung to the simulating 
string-striking position (shown by a two-dotted line in FIG. 16). 
Thereafter, the hammer 750 swings back. If the key is not released while 
the hammer 750 swings back, a catcher 754 is supported by a back check 743 
at a backstop position (shown by a dotted line in FIG. 16). If the key is 
released, the hammer 750 is received by a hammer rail 768 at its 
standstill position. 
Consequently, when generation of an electronic sound is controlled in 
accordance with the movement speed of the hammer 750, to precisely detect 
sound stop information, the sensor needs to be switched on or off 
precisely at the backstop position and the standstill position. Since the 
positions are close to each other, however, it is technically difficult to 
switch on or off the sensor precisely. To solve the problem, it is 
necessary to provide a separate switch to be turned on or off, for 
example, by the key for obtaining sound stop position. There arises a 
problem of increasing cost. 
Also in the keyboard device 701, a hammer skin HS (i.e. the cushion C2) is 
placed on the butt 750a of the hammer 750 for absorbing shock of collision 
with the jack 744, inhibiting collision sound from generating and smoothly 
sliding on the jack 744. Also, a catcher skin CS is placed on the catcher 
754 for absorbing shock arising when the catcher 754 is received by the 
back check 743 and inhibiting collision sound from generating. 
However, since the hammer skin HS is a separate member from the catcher 
skin CS, a cushioning material has to be cut into the separate members to 
be placed, thereby increasing cost. 
Further, when the key 714 is depressed, a capstan button 716 provided 
behind a key support 715 pushes up a felt F of the wippen 730. Thereby, 
the jack 744 is operated and the hammer 750 simulatively strikes a string. 
In this manner, the capstan button 716 has an important function. To 
provide the capstan button 716, the rear side behind the key support 715 
of the key 714 requires a length. It is structurally difficult to shorten 
the key 714. 
SUMMARY OF THE INVENTION 
An object of the invention is to provide a keyboard device manufactured at 
a low cost and having a sufficiently increased accuracy in height of a key 
support. 
Another object of the invention is to provide a keyboard device and an 
assembly method thereof for easily mounting the keyboard to a key bed with 
a high assembly accuracy. 
Another object of the invention is to provide a keyboard device for 
preventing a key support member from being disengaged from a chassis 
without using an exclusive component. 
Another object of the invention is to provide a keyboard device which can 
save cost and simplify mounting operation. 
A further object of the invention is to provide an electronic keyboard 
device which can reproduce the characteristics peculiar to an acoustic 
piano precisely and can be manufactured at a low cost. 
Another object of the invention is to provide a keyboard device which can 
inhibit collision sound in an action mechanism or a simulating action 
mechanism from generating at a low cost. 
Yet another object of the invention is to shorten in a depth direction a 
keyboard device provided with an action mechanism or a simulating action 
mechanism. 
To attain these or other objects, the present invention provides a keyboard 
device having a chassis positioned higher than a top face of a key bed and 
provided with a key support for swingably supporting a key and a plurality 
of ribs provided along a key arrangement direction for reinforcing the 
chassis and extending in a key back-to-forth direction. The ribs regulate 
an interval between the vicinity of the key support and the key bed in the 
chassis to be a predetermined interval. 
In the keyboard device, the chassis is positioned higher than the top face 
of the key bed for swingably support a plurality of keys. The chassis have 
a flat plane including a key arrangement direction and a key back-to-forth 
direction, to define a height of the key support. Further, the ribs 
extending in the key back-to-forth direction are provided in the key 
arrangement direction for reinforcing the chassis. In the chassis, the 
interval between the vicinity of the key support and the key bed is 
regulated to the specified interval. 
Here, the ribs are remarkably smaller than the chassis. Therefore, the ribs 
can be manufactured with a higher accuracy as compared with the bending of 
the large-sized chassis. Therefore, the interval between the vicinity of 
the key support and the key bed can be regulated to the specified interval 
with accuracy, and accuracy in height of the key support is increased. 
Further, by providing a plurality of ribs (e.g. 5 to 15 ribs for all the 
88 keys) in the key arrangement direction, the chassis can be supported 
with a sufficient strength. Additionally, the ribs are already attached to 
the conventional keyboard chassis, thereby adding no cost. 
As aforementioned, according to the keyboard device of the invention, 
accuracy in height of the key support can be increased at a low 
manufacture cost. 
In the invention, each of the ribs comprising a metal plate having a first 
contact face for contacting the vicinity of the key support of the chassis 
and a second contact face for contacting the key bed. The first and second 
contact faces may be formed by bending the plate. In this case, the first 
and second contact faces of the rib can be formed by pressing, for 
example, with a small metallic mold. The accuracy of the rib depends on 
the accuracy of the metallic mold. However, since the small metallic mold 
is manufactured with high accuracy, the rib can have a sufficiently high 
accuracy. The height of the key support is determined by the interval 
between the first and second contact faces of the rib. Therefore, by 
increasing the accuracy of the rib, as a result, the accuracy in height of 
the key support can be increased. 
Also in the invention, a reinforcing member having a configuration 
extending in the key arrangement direction is preferably formed integrally 
with the chassis, and the ribs are preferably fixed to the reinforcing 
member. The reinforcing member can be formed by bending the chassis or 
otherwise, or fixed to the chassis as a separate member extending in the 
key arrangement direction. If no reinforcing member is provided, when an 
obliquely downward force is applied from above, all the ribs are tilted 
and the chassis is deformed. By connecting the ribs to the reinforcing 
member, however, the chassis can resist against the force exerted 
obliquely downward from above. Consequently, the chassis is prevented from 
being deformed and the accuracy is advantageously prevented from being 
deviated. 
In this case, the interval between a portion other than the vicinity of the 
key support of the chassis and the key bed may be regulated to the 
predetermined interval by the reinforcing member. Alternatively, the 
interval between the vicinity of the key support of the chassis and the 
key bed and the interval between the portion other than the vicinity of 
the key support of the chassis and the key bed may be regulated to the 
predetermined intervals, while the reinforcing member is fixed only to the 
ribs and not to the key bed. In either case, the aforementioned effect can 
be obtained. 
Further in the invention, an open space can be provided between the rear 
end of the chassis and the key bed. In this case, a string striking 
porting or a simulating string striking portion (a hammer abutting on a 
stopper instead of actually striking a string) is provided behind the rear 
end of the chassis. An action transmitting member is extended between the 
underside of the key and the open space to the string striking portion or 
the simulating string striking portion, so that key action is transmitted 
to the string striking portion or the simulating string striking portion. 
Here, to provide the open space, for example, the rear end of the chassis 
is formed as a free end. Also, the action transmitting member can be a 
wippen in an action mechanism, a lever for transmitting action to the 
wippen or a lever formed integrally with the hammer. 
In the conventional art, since the interval between the rear end of the 
chassis and the key bed is closed, a hole for passing the action 
transmitting member needs to be formed for each hammer. By providing the 
open space between the rear end of the chassis and the key bed as 
aforementioned, however, the hole does not have to be formed, which is 
cost effective. Also, when assembling a keyboard side and an action side 
including the hammer, the open space can be used, thereby enhancing 
operation efficiency. 
The keyboard device of the invention can be applied either to an electronic 
keyboard instrument or an acoustic keyboard instrument. In the electronic 
keyboard instrument, if the height of the key support is not accurate, an 
adequate key depression data (key depression timing or velocity) cannot be 
obtained. Therefore, the keyboard device of the invention is useful 
especially in the electronic keyboard instrument. 
According to the invention, in the keyboard device where the key support as 
a key swing center is provided on the chassis, a support member for 
supporting the action mechanism or the simulating action mechanism is 
provided on the chassis. In a method of assembling the keyboard device 
according to the invention, before the chassis is disposed on the key bed, 
the keyboard swingably supported by the key support and the action 
mechanism are fixed on the chassis, so that the keyboard and the action 
mechanism are positioned in a predetermined positional relationship. 
The keyboard device of the invention can be applied to a keyboard 
instrument provided with the action mechanism constituted of a wippen, a 
jack, a hammer and the like for actually striking a string, or an 
electronic instrument provided with a simulating action mechanism for 
realizing a touch of an acoustic piano while not striking a string 
actually. Here, the simulating action mechanism is provided with a stopper 
for inhibiting action of the hammer, instead of the string of the action 
mechanism. 
In the keyboard device, in addition to the key support, the action 
mechanism or the simulating action mechanism is also provided on the 
chassis. Specifically, a keyboard unit and an action unit (or a simulating 
action unit) are integrally formed on the chassis beforehand. Here, before 
the chassis is disposed on the key bed, both the units are fixed with 
accuracy on the chassis, so that the units are positioned in the 
predetermined positional relationship, in which when the key swings, in 
the action mechanism or the simulating action mechanism, the hammer 
strikes the string or a simulating hammer strikes a simulating string. In 
this case, intricate operation for positioning the units in the 
predetermined positional relationship on the key bed is not necessary. 
Therefore, the keyboard unit and the action unit can be easily mounted on 
the key bed. For the height of the keyboard and the action mechanism, by 
assembling the keyboard unit and the action unit with accuracy on the 
chassis beforehand, the height of the units is not changed when the 
assembled chassis is disposed on the key bed. Therefore, intricate 
operation for adjusting the height of each key with a capstan screw is not 
necessary. 
As aforementioned, in the keyboard and its assembly method according to the 
invention, the mounting on the key bed can be performed easily and 
accurately. 
Here, in the keyboard device of the invention, for example, the wippen is 
swingably supported on the chassis, the jack is swingably supported on the 
wippen, the hammer is swingably supported on a rail member and the rail 
member may be provided on the chassis. In the keyboard device, each member 
is beforehand positioned in a predetermined positional relationship, in 
which when the key swings, the wippen swings, the jack accordingly swings 
and moves, then the hammer accordingly swings. Therefore, a touch of an 
acoustic piano can be obtained. In this case, the hammer may actually 
strike a string, or collide against the stopper instead of striking the 
string (the hammer having the latter function is referred to as the 
simulating hammer). 
In this case, the rail member is preferably provided in the vicinity of the 
rear end of the keyboard on the chassis. The reason is that the farther 
the rail member is behind the rear end of the keyboard, the larger the 
depth dimension of the keyboard device becomes, and by providing the rail 
member in the vicinity of the rear end of the keyboard on the chassis to 
shorten the depth dimension of the keyboard device, the keyboard device 
can be preferably formed in a compact structure. 
Also, for the wippen, a wippen swing axis is swingably supported on a 
bearing provided on a chassis (i.e. the wippen is supported directly on 
the chassis). Alternatively, the wippen swing axis can be swingably 
supported on the rail member provided on the chassis (i.e. the wippen is 
indirectly supported on the chassis). However, in the latter case, the 
weight of the wippen is applied to the rail member, and the rail member 
has an increased load. There arises a need for strengthening the rail 
member. In this respect, the former constitution for directly supporting 
the wippen on the chassis is preferable. 
Further, when the keyboard device of the invention is applied to an 
electronic keyboard instrument, a key depression sensor for detecting key 
depression information is preferably formed in the chassis. A positional 
relationship between the key depression detecting sensor and the keyboard 
is predetermined, and the key depression detecting sensor is positioned 
integrally on the chassis with accuracy beforehand. When the chassis is 
mounted on the key bed, the predetermined positional relationship is 
unchanged. In this case, there is no need of positioning the key 
depression detecting sensor and the keyboard unit separately on the key 
bed. As a result, the mounting on the key bed can be simplified. 
Also, the invention provides a keyboard device in which a key support 
member including a swing center of a key and a rail member provided with a 
hammer swinging in response to swinging of the key are fixed on a chassis. 
The key support member is inserted in an inlet provided in the chassis. 
The rail member is fixed so that the key support member is not detached 
from the inlet in the chassis. 
In the keyboard device, a component for fixing the key support member onto 
the chassis is not provided separately. The key support member is 
prevented from being detached from the chassis using the rail member 
provided with the hammer. 
Therefore, according to the keyboard of the invention, component cost can 
be saved as compared with the case where the separate component is used. 
Also, by fixing the rail member to the chassis, the key support member can 
be effectively prevented from being detached from the chassis. There is no 
need of attaching the separate component. 
Here, the key support member can be inserted in the inlet in the chassis 
with clearance, and can be engaged with a peripheral portion of the inlet. 
The rail member may be constituted to support the key support member 
inserted with clearance in the inlet and engaged with the peripheral 
portion of the inlet. The key support member is first inserted with 
clearance in the inlet, and is then engaged with the peripheral portion of 
the inlet. In this case, the key support member is engaged with the inlet 
without the rail member. The key support member can be temporarily fixed 
to the chassis. Therefore, operation efficiency is improved. 
In the keyboard device of the invention, the key support member is 
preferably provided with a holding portion having a configuration 
including a substantially U-shaped configuration, and the holding portion 
is engaged so as to hold the peripheral portion of the inlet. The key 
support member provided with the holding portion is prevented from moving 
vertically relative to the chassis. For this purpose, the key support 
member is preferably provided with a plurality of the holding portions. If 
one holding portion is provided, the engaged key support is possibly 
tilted. 
Also in the keyboard device of the invention, the key support member is 
preferably at the rear end of the keyboard. Usually, the rail member for 
supporting the swing axis of the hammer is attached behind the keyboard. 
Therefore, the key support member provided at the rear end of the 
keyboard, rather than around the middle of the keyboard, can be more 
easily fixed by the rail member. 
Further in the keyboard device of the invention, the rail member is 
preferably fastened via a guide hole or a guide groove (hereinafter 
referred to as the guide hole or the like) provided therein by a fastening 
member (e.g. bolt and nut, screw and hole, vis screw or the like) on the 
chassis. By loosening the fastening member, the rail member can be slid 
and moved along the guide hole or the like between a position at which the 
key support member is prevented from being detached from the chassis and a 
position at which the key support member is permitted to be detached from 
the chassis. In case of replacement of the keyboard, the fastening member 
and the rail member are detached to detach the key support member from the 
chassis, which is an intricate operation. According to the invention, 
however, just by loosening the fastening member and sliding the rail 
member along the guide hole or the like, the key support member can be 
detached from the chassis. The operation efficiency is remarkably 
enhanced. The guide hole or the like includes an elliptical hole, an 
elongated hole, an elongated groove or the like. 
Further, the keyboard device according to the invention can be provided 
with a wippen swingably supported on a chassis or a rail member, a jack 
swingably supported on a wippen, and a hammer swinging centering on a 
hammer swing axis provided on the rail member when the jack swings and 
moves. In operation, when the key swings, the wippen swings, the jack 
accordingly swings and moves, then the hammer swings centering on the 
hammer swing axis. Therefore, a touch of an acoustic piano can be 
obtained. In this case, the hammer may actually strike a string, or 
collide against a stopper instead of striking the string. 
In this case, not only the keyboard but all the members constituting the 
action mechanism (the wippen, the hammer and the like) are mounted on the 
chassis (or a center rail provided on the chassis). When each member is 
accurately mounted on the chassis beforehand, there is no need of 
positioning each member on the key bed. Therefore, the mounting on the key 
bed can be simplified. Since the keyboard and the members constituting the 
action mechanism are accurately mounted on the chassis, they can be 
mounted on the key bed without changing their height. Therefore, intricate 
operation for adjusting the height of each key with a capstan screw is 
unnecessary. 
The present invention also provides a keyboard device provided with a 
wippen swinging when a key swings, a jack swingably supported by the 
wippen for swinging and moving when the wippen swings and having its 
action regulated by a regulating member during acting, and a hammer. 
The hammer is provided swingably between an initial position regulated by a 
hammer cushion member and a string striking position (or a simulating 
string striking position) regulated by a string (or a hammer stopper). 
When the jack swings and moves, the hammer starts swinging. When the 
action of the jack is regulated by the regulating member, the hammer is 
disengaged from the jack and starts inertial movement to reach the string 
striking position (or the simulating string striking position). 
The regulating member and the hammer cushion member is provided on the same 
support member. 
The keyboard device can be applied to a keyboard instrument provided with 
an action mechanism constituted of a wippen, a jack and a hammer for 
actually striking a string, or an electronic instrument provided with a 
simulating action mechanism for producing a touch of an acoustic piano 
without striking a string. Here, the simulating action mechanism is 
provided with a hammer stopper for inhibiting the hammer from acting 
instead of the string of the action mechanism. 
In the keyboard device, when a key is depressed to swing, the wippen swings 
and the jack swingably supported by the wippen moves upward and swings, 
following swinging of the wippen. The jack moves upward to push up the 
hammer while swinging. The hammer starts swinging from the initial 
position. Subsequently, the jack is regulated to move apart from the 
hammer by the regulating member during its action. Therefore, the hammer 
starts inertial movement independent of the jack. This timing is a 
letting-off timing. Thereafter, the hammer continues inertial movement to 
reach the string striking position (or the simulating string striking 
position). At the string striking position, the hammer actually strikes a 
string, while at the simulating string striking position, the hammer 
collides against a hammer stopper provided instead of the string. 
In the keyboard device the regulating member for regulating the action of 
the jack while the jack is acting and the hammer cushion member for 
regulating the initial position of the hammer are provided on the same 
support member. This is cost effective as compared with the case where 
these members are provided on separate support members. 
Also, in order to determine the letting-off timing, the mounting accuracy 
of the regulating member requires to be high. To determine a key touch 
property applied to a finger depressing a key, the mounting accuracy of 
the hammer cushion member requires to be high. For this purpose, the 
regulating member and the hammer cushion member are provided on the 
support member by considering the letting-off timing and the initial 
position of the hammer beforehand. The aforementioned two requirements can 
be satisfied just by increasing the mounting accuracy of the support 
member. The mounting operation is simplified as compared with the case 
where two separate members (e.g. the regulating rail 861 and the hammer 
rail 869 in FIG. 8) are mounted. 
Here, in the keyboard device of the invention, the support member is 
provided with two faces: one face is provided with the regulating member 
and the other face is provided with the hammer cushion member. In this 
case, since the support member is constituted simply, the mounting 
accuracy can be increased without increasing the manufacture cost of the 
support member. 
Also in the keyboard device of the invention, the wippen, the hammer and 
the support member can be provided directly or via another member on the 
chassis supporting the key support of the keyboard. Specifically, since 
the action mechanism (or the simulating action mechanism) and the keyboard 
are provided on the same chassis, by mounting both with accuracy on the 
chassis beforehand, there is no need of positioning the action mechanism 
(or the simulating action mechanism) and the keyboard on the key bed as in 
the conventional art. The mounting on the key bed can be simplified. 
Further in the keyboard device of the invention, the hammer and the support 
member are provided on a rail member connected to the chassis. The hammer 
is usually swingably supported by a center rail as the rail member. Here, 
to determined the initial position of the hammer, the positional 
relationship between the hammer cushion member and the hammer is 
important. For this, in order to easily position the hammer cushion member 
and the hammer, the support member provided with the hammer cushion member 
is preferably attached to the rail member provided with the hammer. 
Still further in the keyboard device of the invention, the hammer stopper 
for stopping the inertial movement of the hammer is provided at the 
simulating string striking position. The hammer stopper can also be 
provided on the rail member. In this case, a separate component for 
supporting the hammer stopper is unnecessary. Therefore, cost can be 
saved. Additionally, when the hammer stopper is provided on the support 
member by predetermining the simulating string striking position, the 
accuracy required for the hammer stopper can be obtained just by 
increasing the mounting accuracy of the support member. The mounting 
operation is simplified as compared with the case where three separate 
members (e.g. the regulating rail 861, the hammer rail 869 and the hammer 
stop rail 862 in FIG. 8) are mounted. 
The invention also provides a keyboard device for an electronic instrument 
provided with a wippen swinging when a key swings, a jack swingably 
supported by the wippen for swinging and moving when the wippen swings and 
having its action regulated during acting, a hammer starting swinging when 
the jack swings and moves, moving apart from the jack when the jack has 
its action regulated, and starting inertial movement until reaching the 
simulating string striking position, and an information detector for 
detecting information as a basis of performance information in response to 
swinging of the wippen. 
The wippen has a larger inertial moment than the jack and the hammer. 
The keyboard device can be applied to an electronic keyboard instrument 
provided with a simulating action mechanism for realizing a touch of an 
acoustic piano without actually striking a string. Here, the simulating 
action mechanism is provided with a hammer stopper for stopping the action 
of the hammer, instead of the string of the action mechanism. Also, the 
keyboard device of the invention can be applied to a keyboard instrument 
provided with both a string and a hammer stopper, in which a hammer can 
selectively collide against the string or the hammer stopper. 
In operation of the keyboard device, when a key is depressed to swing, the 
wippen swings accordingly, and the jack swingably supported by the wippen 
then moves upward and swings. Since the jack moves upward to push up the 
hammer while swinging, the hammer starts swinging. Subsequently, during 
its action, the jack is regulated to move apart from the hammer. The 
hammer in turn starts inertial movement independent of the jack. This 
timing is a letting-off timing. Thereafter, the hammer continues inertial 
movement until reaching the simulating string striking position. Here, at 
the simulating string striking position, the hammer collides against the 
hammer stopper instead of the string. 
In the keyboard device, when the key is depressed from its standstill 
position to the full-stroke position, the wippen swings from a position 
corresponding to the standstill position of the key (hereinafter referred 
to as the wippen initial position) to a position corresponding to the 
full-stroke position of the key (hereinafter referred to as the wippen 
swing position). Then, the information detector detects the information as 
a basis of the performance information in response to the swinging of the 
wippen. 
The information detector may be constituted to determine first and second 
positions between the wippen initial position and the wippen swing 
position, and detect a timing when the wippen reaches the first position 
and a timing the wippen reaches the second position. Both timings 
correspond to the information as the basis of the performance information. 
For example, the velocity indicating sound intensity as one piece of 
performance information is obtained based on a difference between the 
timing when the wippen reaches the first position and the timing when the 
wippen reaches the second position. Also, the sound stop information as 
another piece of performance information is obtained based on a timing 
when the wippen again reaches the first position. In this manner, the 
information detector has a simple constitution just for detecting the 
timings when the wippen reaches the first and second positions. 
In the invention, the wippen has a larger inertial moment than the jack and 
the hammer. Therefore, after the key is depressed at high speed, the 
wippen does not instantly start swinging. The wippen more remarkably 
withstands to some degree before starting swinging than the jack and the 
hammer. Since the jack and the hammer have a smaller inertial moment than 
the wippen, they start swinging immediately after the wippen swings. 
Therefore, in the invention, the wippen realizes the aforementioned 
characteristics peculiar to an acoustic piano, i.e. a relationship between 
a key touch when a key is depressed at high speed and a loudness of an 
accordingly produced electronic sound, and a time lag after the key is 
depressed until sound is produced. 
Therefore, by detecting the basic information of the performance 
information in response to action of the wippen, the performance 
information for precisely reproducing the characteristics peculiar to an 
acoustic piano can be obtained. Therefore, when a player operates the 
keyboard device of the invention in the same manner when playing an 
acoustic piano, a sound is generated in the same manner as in the acoustic 
piano. The player does not feel difference. 
Additionally, since each wippen acts corresponding to each key, sound stop 
information as a piece of performance information can also be precisely 
obtained based on the information detected by the information detector. In 
this respect, for example, when the basic information of the performance 
information is detected in response to action of the hammer, it is 
difficult to precisely obtain sound stop information, because each hammer 
does not act corresponding to each key. In this case, a separate detector 
is provided for the keyboard or the like, so that the sound stop 
information is obtained based on the information detected by the detector, 
which adds to cost. In the invention, however, no separate detector is 
necessary and no cost is added. 
In the keyboard device of the invention, in order to make large the 
inertial moment of the wippen, the swing radius of the wippen is 
preferably larger than the swing radium of the jack or the hammer. Also, a 
weight is preferably attached to an end of the wippen to increase the 
inertial moment. 
Also in the keyboard device according to the invention, in the same manner 
as an acoustic piano, the key preferably abuts on the wippen via a cushion 
material. The wippen formed of either wood or synthetic resin is 
resiliently deformed to some degree. Therefore, when the key swings at 
high speed, the wippen can store its force as aforementioned. When the 
cushion material is interposed between the key and the wippen, the cushion 
material is resiliently deformed in addition to resilient deformation of 
the wippen. Therefore, the force transmitted from the key can be easily 
stored in the wippen. In this case, the characteristics peculiar to an 
acoustic piano remarkably appear. Therefore, the invention is valuable in 
that the inertial moment of the wippen is maximized and the basic 
information of the performance information is detected in accordance with 
action of the wippen. 
Further, when released, the key is given a force by the wippen receiving 
the weights of hammer and others such that the front end of the key is 
swung upward. The key is also held at its standstill position by the 
force. In this respect, considering that the key is effectively held at 
the standstill position, in the invention, the inertial moment of the 
wippen is preferably set higher than the inertial moment of the key. In 
this case, even if the jack and the wippen are made lighter and smaller to 
have a remarkably small inertial moment, the key can be effectively held 
at the standstill position. 
The invention also provides a keyboard device provided with a wippen 
swinging when a key swings, a jack swingably supported by the wippen for 
swinging and moving when the wippen swings and having its action regulated 
during acting, a hammer starting swinging when the jack swings and moves, 
moving apart from the jack when the jack has its action regulated, and 
starting inertial movement until reaching a string striking (or a 
simulating string striking) position, and a back check for catching the 
hammer swinging back after reaching the string striking (or the simulating 
string striking) position. 
The hammer is provided with a butt on which the jack can abut and a catcher 
portion caught by a back check portion of the wippen. 
A shock absorbing member is provided for continuously covering the butt 
portion and the catcher portion. 
The keyboard device can be applied both to an electronic instrument 
provided with a simulating action mechanism for providing a touch of an 
acoustic piano without actually striking a string, and to a keyboard 
instrument provided with an action mechanism constituted of a wippen, a 
jack and a hammer for actually striking a string. Here, the simulating 
action mechanism is provided with a hammer stopper for inhibiting the 
hammer from acting, instead of, for example, a string of the action 
mechanism. 
In the keyboard device, when the key is depressed to swing, the wippen 
accordingly swings, and the jack swingably supported by the wippen moves 
upward and swings accompanying the swinging wippen. The jack moves upward 
to push up the hammer, while swinging. Then, the hammer starts swinging. 
During acting, the jack has its action regulated to move apart from the 
hammer. Therefore, the hammer starts inertial movement independently of 
the jack. This timing is a letting-off timing. Thereafter, the hammer 
continues inertial movement until reaching the string striking (or the 
simulating string striking) position. At the string striking position, the 
hammer actually strikes a string, while at the simulating string striking 
position, the hammer collides against the hammer stopper instead of, for 
example, the string. The hammer swinging back after reaching the string 
striking (or the simulating string striking) position is caught by the 
back check while the key is depressed, or returns to its initial position 
when the key is released. 
Here, the keyboard device of the invention is provided with the shock 
absorbing member continuously covering the butt portion and the catcher 
portion of the hammer. The shock absorbing member prevents an impact sound 
from being generated while the jack and the butt portion of the hammer, or 
the back check and the catcher portion of the hammer are shifted from a 
non-contact condition to a contact condition. 
Since the shock absorbing member is formed to continuously cover the butt 
portion and the catcher portion, the shock absorbing member needs not to 
be cut in pieces or placed individually, thereby reducing cost, as 
compared with the case where the butt portion and the catcher portion are 
individually covered. According to the keyboard device of the invention, 
an impact sound can be effectively prevented from being generated in the 
action mechanism or the simulating action mechanism at a low cost. 
Here, considering the efficiency of operation for providing the shock 
absorbing member so as to continuously cover the butt portion and the 
catcher portion of the hammer, the butt portion and the catcher portion of 
the hammer are preferably provided on a continuous face. To easily realize 
such constitution, for example, the hammer is preferably molded as a 
configuration including the butt portion and the catcher portion. 
In the keyboard device of the invention, a hammer cushion can be provided 
for regulating the initial position of the hammer. The hammer may be 
provided with a rest portion for abutting on the hammer cushion and the 
shock absorbing member may be formed so as to continuously cover the rest 
portion, the butt portion and the catcher portion. In this case, an impact 
sound is absorbed when the rest portion collides against the hammer 
cushion. Further, since the shock absorbing member continuously covers the 
butt portion, the catcher portion and the rest portion, cost can be 
reduced as aforementioned. In this case, considering the efficiency of 
operation in continuously providing the shock absorbing member, the butt 
portion, the catcher portion and the rest portion are preferably provided 
on a continuous face. To easily realize such constitution, for example, 
the hammer is preferably molded in a configuration including the butt 
portion, the catcher portion and the rest portion. 
The invention further provides a keyboard device provided with a key 
swingably supported by a key support, a wippen swinging centering on a 
wippen axis when the key swings, a jack swingably supported by a jack axis 
provided on the wippen for swinging and moving when the wippen swings and 
having its action regulated during acting, and a hammer starting swinging 
when the jack swings and moves, moving apart from the jack when the jack 
has its action regulated, and starting inertial movement until reaching a 
string striking (or a simulating string striking) position. 
The wippen has on one end a depressed portion depressed by the underside of 
the key and on the other end the jack axis rising when the depressed 
portion is depressed. 
Between the depressed portion and the jack axis is provided the key support 
for swingably supporting the key. 
The keyboard device can be applied both to an electronic instrument 
provided with a simulating action mechanism for providing a touch of an 
acoustic piano without actually striking a string and to a keyboard 
instrument provided with an action mechanism constituted of a wippen, a 
jack and a hammer for actually striking a string. Here, the simulating 
action mechanism is provided with a hammer stopper for inhibiting the 
hammer from acting, instead of, for example, a string of the action 
mechanism. 
In the keyboard device, when the key is depressed to swing, the wippen 
accordingly swings centering on the wippen axis, and the jack swingably 
supported by the jack axis provided on the wippen moves upward and swings 
accompanying the swinging wippen. The jack moves upward to push up the 
hammer, while swinging. Then, the hammer starts swinging. During acting, 
the jack has its action regulated to move apart from the hammer. 
Therefore, the hammer starts inertial movement independently of the jack. 
This timing is a letting-off timing. Thereafter, the hammer continues 
inertial movement until reaching the string striking (or the simulating 
string striking) position. At the string striking position, the hammer 
actually strikes a string, while at the simulating string striking 
position, the hammer collides against, for example, the hammer stopper, 
instead of the string. 
Here, the wippen is swingably supported by the wippen axis, and has on one 
end the depressed portion and on the other end the jack axis. The key 
support is provided between the depressed portion and the jack axis of the 
wippen. Therefore, when the key is depressed, the depressed portion 
provided on one end of the wippen is depressed by the underside of the key 
before the key support. Then, the wippen swings centering on the wippen 
axis, and the jack axis provided on the other end of the wippen rises. 
Thereby, the jack acts on the hammer, so that the hammer actually (or 
simulatingly) strikes a string. 
Therefore, in the keyboard device of the invention, since the portion 
behind the key support of the key does not particularly function, the 
corresponding portion can be shortened. According to the invention, by 
reducing the length of the key, the length in the depth direction of the 
keyboard device can be advantageously shortened. 
As aforementioned, in the invention since the portion behind the key 
support of the key does not especially function, the keyboard can have the 
portion behind the key support (or its vicinity) cut away. In this case, 
the keyboard device is shortened remarkably in a depth direction. 
Further in the keyboard device of the invention, the wippen axis can be 
disposed between the key support and the jack axis (i.e. behind the key 
support). In this case, a space is required behind the key support for 
providing the wippen axis. Therefore, the keyboard device may be 
lengthened in the depth direction. To solve such disadvantage, the wippen 
axis is preferably provided between the key support of the key and the 
depressed portion of the wippen (i.e. before the key support).

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
Embodiments of the present invention are now described with reference to 
accompanying drawings. The invention is not restricted to following 
embodiments, and various modifications and alterations are possible within 
the scope of the appended claims. 
First Embodiment 
FIG. 1 is a sectional view of a keyboard device according to the first 
embodiment, in which a key is released. FIG. 2 is a sectional view showing 
the keyboard device in a simulating string striking condition. FIGS. 1 and 
2 illustrate a white key. A black key is the same as the white key except 
the constitution of the key itself. 
A keyboard device 1 for use in an electronic keyboard instrument is 
provided mainly with a chassis 11, a rib 19, a key 14, a wippen 30, a 
center rail 60, a hammer 50 and the like. Here, the wippen 30 is similar 
to, but not the same as the action lever 605 shown in FIG. 6. 
Specifically, the action lever 605 of FIG. 6 transmits a key action to the 
wippen, while in the embodiment the wippen 30 only has a function of 
wippen itself 
The chassis 11 is provided with a flat portion 12 positioned higher than a 
top face of a key bed 2, and a leg portion 13 fixed as a separate 
component to a front end of the flat portion 12. The flat portion 12 is a 
plane including an arrangement direction of keys 14 (vertical to a sheet 
surface of FIGS. 1 and 2, the same in the following) and a back-to-forth 
direction of keys 14 (right to left direction in FIGS. 1 and 2, the same 
in the following). On a rear end of the flat portion 12 a bearing is fixed 
16 for supporting a key support 15 of each of all the 88 keys. 
The bearing 16 has substantially L-shaped legs 18 thereunder. After the 
L-shaped legs 18 are inserted in holes 17, by sliding the bearing 16 
toward the front of the key (to the left in FIGS. 1 and 2), the flat 
portion 12 is held between the L-shaped legs 18 and the underside of the 
bearing 16. In this condition, by fixing a front end of a flange portion 
61 of the center rail 60 to abut on a rear end of one of the L-shaped legs 
18 (the rear leg, i.e. the right L-shaped leg 18 as seen in FIG. 1), the 
bearing 16 is fixed immobile on the flat portion 12 of the chassis 11. In 
this case, the bearing 16 is precisely positioned on the chassis 11. 
On the flat portion 12, an opening 25 is provided on each key for 
vertically passing a front end of the wippen 30. Further, the rear end of 
the flat portion 12 is a free end slightly bent upward. Therefore, an open 
space 39 is provided between the rear end of the flat portion 12 and the 
key bed 2. 
The leg portion 13 of the chassis 11 extends in the arrangement direction 
of the keys 14 and has a substantially U-shaped cross section. An upper 
flange portion 13a of the leg potion 13 is fixed with a screw on the flat 
portion 12, and a lower flange portion 13b is fixed with a screw on the 
key bed 2. Therefore, the height of the front end of the flat portion 12 
is defined by the leg portion 13. 
The rib 19 is a plate member extending in the back-to-forth direction of 
the key 14. A front flange portion 20 is fixed with a screw on the leg 
portion 13 of the chassis, upper flange portions 21a, 21b and 21c are 
fixed with a screw on the flat portion 12 of the chassis, and a lower 
flange portion 22 is fixed with a screw on the key bed 2. 
The height of the rear end of the flat portion 12 (i.e. the vicinity of the 
key support 15) is defined by the upper flange portion 21c (a first 
contact face in the invention) and the lower flange portion 22 (a second 
contact face in the invention) opposed to the upper flange portion 21c. 
The rib 19 is formed by pressing a metallic plate material in a metallic 
mold, and each of the flange portions 20-22 is formed by bending the 
material in the metallic mold. Thereby, the manufacturing cost of the rib 
19 can be reduced, and the accuracy of the rib 19 can be high since it is 
dependent on a small-sized metallic mold. Therefore, the height of the key 
support 15, i.e. the height of the rear end of the flat portion 12 can be 
defined with sufficient accuracy. 
The key 14 (white key in the embodiment) is formed in a hollow body of 
synthetic resin provided with several reinforcing ribs. The rear end of 
the key 14 is swingably attached to the key support 15. Therefore, the tip 
of the key 14 can vertically swing centering on the key support 15. From 
the tip of the key 14, a hook-shaped arm 24 extends downward. The 
hook-shaped arm 24 has a hook portion 24a bent toward the key support 15. 
When the key 14 is not depressed, as shown in FIG. 1, the hook portion 24a 
of the hook-shaped arm 24 abuts on a longitudinal felt 26b provided on the 
underside of the front end of the flat portion 12 of the chassis 11. When 
the key 14 is depressed, as shown in FIG. 2, the underside of the front 
end of the key 14 abuts on the longitudinal felt 26a provided on a top 
face of the front end of the flat portion 12 of the chassis 11. Further, 
in a hollow portion of the front end of the key 14 a key guide portion 27 
is inserted and is directed upward at the front end of the flat portion 12 
of the chassis 11. The key guide portion 27 guides a tip of the key 14 
when the key is operated, while preventing the tip from horizontally 
oscillating. 
Below the key 14, the wippen 30 (action transmitting member of the 
invention) is swingably supported by a substantially U-shaped bearing 
member 33 on a wippen swing axis 31 of the chassis 11. The bearing member 
33 is provided with a bearing member fixing plate 34 for covering the 
wippen swing axis 31 from above. The bearing member fixing plate 34 and 
the bearing member 33 are fixed with the same screw like cantilevers on 
the chassis 11. The wippen swing axis 31 is prevented by the bearing 
member fixing plate 34 from being disengaged from the bearing member 33. 
Further, the bearing member 33 is precisely positioned and attached on the 
chassis 11. 
A front end of the wippen 30 is disposed to be vertically moved above and 
below the chassis 11 via the opening 25 of the chassis 11 when the wippen 
30 swings centering on the wippen swing axis 31. A top face of the front 
end of the wippen 30 is provided with a sliding tape 32 (cushion material 
of the invention) having a small surface frictional resistance. The 
sliding tape 32 is in contact with a tip of an actuator 35 protruded from 
the underside of the key 14. The sliding tape 32 is constituted of two 
layers: an urethane foam layer for absorbing impact and an artificial 
leather surface layer for providing slidability. 
Below the front end of the wippen 30, a base 28 extending in the key 
arrangement direction is attached on the chassis 11 with a predetermined 
interval from the flat portion 12 of the chassis 11. On the base 28, a key 
depression detecting sensor 37 is provided opposite to the wippen 30 
provided for each of all the 88 keys. As shown in FIG. 15, the key 
depression detecting sensor 37 has inside two switches S1 and S2. When the 
key 14 at the initial position is depressed to cause the actuator 35 to 
depress the front end of the wippen 30, first one switch S1 turns on. When 
the key 14 is further depressed, the other switch S2 turns on. 
Subsequently, the key 14 reaches its full-stroke position. According to 
the invention, the wippen 30 takes a first position when the switch S1 
turns on, and takes a second position when the switch S2 turns on. From on 
and off-timings of the switches S1 and S2 and a difference in timings 
between the switches, key depression/release timings and velocities can be 
obtained, based on which a sound is produced from an electronic sound 
source under control of an electronic control circuit (not shown) with a 
musical interval corresponding to the position of the key and sound 
intensity corresponding to the key depression velocity at a timing 
corresponding to the key depression timing, and sounding is stopped at the 
key release timing. Further, the key depression detecting sensor 37 is 
precisely positioned on the base 28 by considering the positional 
relationship with the key 14. 
On a rear end of the wippen 30, a bearing portion 42 for supporting a jack 
rotation axis 45 and a back check 43 for receiving the swung back hammer 
50 are provided integrally with accuracy. 
The rear end of the wippen 30 is provided with a weight 41, so that the 
inertial moment of the wippen 30 is larger than that of a jack 44 and the 
hammer 50. Also, a swing radius (i.e. a length between the wippen swing 
axis 31 and the weight 41) of the wippen 30 is longer than that of the 
jack 44 and the hammer 50. In the embodiment, to lengthen the swing radius 
of the wippen 30, the rear end of the wippen is passed through the open 
space 39 between the rear end of the flat portion 12 of the chassis 11 and 
the key bed 2 to reach behind the rear end of the flat portion 12 of the 
chassis 11. 
The jack 44 has a substantially L-shaped cross section, and the jack 
rotation axis 45 is provided on a bent portion of the L-shaped cross 
section. A jack tail 47 is connected with the wippen 30 via a compression 
coil spring 46. 
The center rail 60 is extended in the key arrangement direction, and 
provided with a rising portion 62 extending substantially vertical to the 
flat portion 12 of the chassis 11, the flange portion 61 bent from a lower 
end of the rising portion 62 toward the front of the key 14 and a stop 
rail portion 63 extending obliquely upward from an upper end of the rising 
portion 62 to the rear side. The center rail 60 is positioned with 
accuracy on the flat portion 12 of the chassis 11 and fixed with a screw. 
A front end of the flange portion 61 of the center rail 60 is fixed 
abutting on the rear L-shaped leg 18, so that the rear L-shaped leg 18 of 
the bearing 16 for supporting the key support 15 is prevented from sliding 
in the corresponding hole 17. 
On the rising portion 62 of the center rail 60, a rail 67 having a 
substantially L-shaped cross section is extended along the key arrangement 
direction and fixed with a screw. On a top face of the rail 67 provided is 
a hammer cushion 68 for abutting on a rest portion 52 of the hammer 50 
while the key is released. The underside of the rail 67 is provided with a 
regulating felt 66 for abutting on the jack tail 47. Further, on the 
underside of the stop rail portion 63 provided is a stop felt 63a 
extending in the key arrangement direction. In this manner, since the 
hammer cushion 68 and the regulating felt 66 are provided on the rail 67, 
cost can be reduced as compared with the case where they are provided on 
separate rails. Further, the rail 67, the regulating felt 66 and the 
hammer cushion 68 are positioned with accuracy before fixed. 
Further, the center rail 60 is provided with an action rib 70 for 
reinforcement. The action rib 70 is fixed at two places with a screw on 
the rising portion 62 of the center rail 60, and at one place with a screw 
on the flange portion 61 of the center rail 60. 
A hammer swing axis 51 provided on the front end of the hammer 50 is 
swingably supported by a bearing member 65 which has a substantially 
U-shaped cross section and is inserted in a square hole in the rising 
portion 62 of the center rail 60. The bearing member 65 is provided with a 
bearing member fixing plate 71 for covering the hammer swing axis 51. The 
bearing member fixing plate 71 and the bearing member 65 are fixed with a 
screw like cantilevers to the center rail 60. The hammer swing axis 51 is 
prevented by the bearing member fixing plate 71 from being disengaged from 
the bearing member 65. Further, the bearing member 65 is positioned with 
accuracy on the center rail 60 before attached thereto. 
The underside of the hammer 50 is provided with the rest portion 52 for 
abutting on the hammer cushion 68, a butt portion 53 having a 
substantially S-shaped cross section on or from which the tip of the jack 
44 abuts or moves apart, and a catcher portion 54 for abutting on the back 
check 43 of the wippen 30. The hammer 50 is molded of synthetic resin into 
a configuration including the rest portion 52, the butt portion 53 and the 
catcher portion 54. Therefore, the rest portion 52, the butt portion 53 
and the catcher portion 54 are provided on a continuous plane. On the 
hammer 50, a cushion material 56 (the shock absorbing member of the 
invention) is continuously placed for covering the rest portion 52, the 
butt portion 53 an the catcher portion 54. The cushion material 56 is 
constituted of two layers: an urethane foam layer for absorbing impact and 
an artificial leather surface layer for providing slidability. A portion 
of the cushion material 56 on which the tip of the jack 44 abuts while the 
key is not depressed is provided with a cushion material 57 for absorbing 
an impact noise generated when the jack 44 is returned or biased by the 
compression coil spring 46 to abut on the cushion material 56 of the 
hammer 50 after the key is released. 
When the hammer 50 swings counterclockwise in FIG. 1 centering on the 
hammer swing axis 51, a simulating string striking portion 58 on the top 
face of the hammer 50 collides against the stop felt 63a provided on the 
center rail 60. The simulating string striking portion 58 is provided with 
a cushion material for absorbing an impact noise generated when the hammer 
50 collides against the stop felt 63a. 
The rear end of the hammer 50 is provided with a weight 59 by considering 
the gravity center of a hammer and the swinging back of the hammer in an 
action mechanism of an acoustic piano. The inertial moment of the hammer 
50 is set smaller than that of the wippen 30. 
The wippen 30, the jack 44 and the hammer 50 are all formed of synthetic 
resin, and are not distorted over a long time period. 
In the keyboard device 1 having the aforementioned constitution, when the 
key is not depressed, as shown in FIG. 1, the weight 41 and the like of 
the wippen 30 exerts the moment of a clockwise force on the front end of 
the wippen 30 and also on the actuator 35, so that the key 14 tries to 
swing clockwise. However, the key 14 is inhibited from swinging clockwise 
because the hook portion 24a of the hook-shaped arm 24 abuts on the 
longitudinal felt 26b. 
When a player depresses the key 14, the key 14 swings centering on the key 
support 15 counterclockwise in FIG. 1. Thereby, the front end of the 
wippen 30 is depressed by the actuator 35, and the wippen 30 swings 
counterclockwise centering on the wippen swing axis 31. The underside of 
the front end of the wippen 30 depresses the key depression detecting 
sensor 37, while the rear end of the wippen 30 swings upward. Accompanying 
the swinging of the wippen 30, the jack 44 rises to push up the butt 
portion 53 of the hammer 50, while swinging counterclockwise relative to 
the wippen 30. Subsequently, after the jack tail 47 of the jack 44 abuts 
on the regulating felt 66, the jack 44 immediately swings counterclockwise 
on a support of abutting place between the jack tail 47 and the regulating 
felt 66. The tip of the jack 44 moves apart from the butt portion 53 of 
the hammer 50, which is a letting-off action. Therefore, in the simulating 
action mechanism, the letting-off action is given in the same manner as in 
the action mechanism. In this case, since the jack 44 abuts on the butt 
portion 53 via the cushion material 56, no unusual noise is generated. 
Further, the jack 44 easily slides on the hammer 50. 
After the letting-off action, the hammer 50 starts inertial movement while 
continuing to swing counterclockwise. Subsequently, the simulating string 
striking portion 58 of the hammer 50 collides against the stop felt 63a, 
as shown in FIG. 2. Thereby, the inertial movement of the hammer 50 is 
inhibited. Subsequently, the hammer 50 swings in reverse or clockwise. 
When the hammer 50 thus swings back, if the key 14 is released, the rest 
portion 52 of the hammer 50 abuts on the hammer cushion 68. In this 
condition, the hammer 50 is stopped at its initial position (refer to FIG. 
1). Since the rest portion 52 is covered with the cushion material 56, no 
impact noise is generated even when the rest portion 52 collides against 
the hammer cushion 68. On the other hand, when the hammer 50 swings back, 
if the key 14 continues to be depressed, the catcher portion 54 of the 
hammer 50 is received at a back stop position (shown by a dotted line in 
FIG. 2) by the back check 43 provided on the rear end of the wippen 30, 
before the rest portion 52 of the hammer 50 abuts on the hammer cushion 
68. In this case, since the catcher portion 54 is covered with the cushion 
material 56, no impact noise of the catcher portion 54 colliding against 
the back check 43 is generated. 
The case when the key 14 having some defect needs to be disassembled is 
described referring to FIGS. 9 and 10. In this case, first by slightly 
loosening a screw 8, the center rail 60 is slid along an elongated hole 
61a formed in the key back-to-forth direction toward the rear side (to the 
right in FIGS. 9 and 10). Thereby, the center rail 60 is positioned at a 
position (refer to FIG. 10) at which the bearing 16 can be detached from 
the hole 17. Subsequently, the bearing 16 is moved in the hole 17 toward 
the rear side, to release the L-shaped leg 18 from the hole 17, and is 
pulled upward (refer to FIG. 10). In this manner, according to the 
embodiment, the bearing 16 can be pulled up or removed to disassemble the 
key 14, without removing the screw 8 and the center rail 60. 
The center rail 60 is extended in the key arrangement direction and 
provided, for example, for each octave. The screw 8 can be provided for 
each key 14. However, the screw 8 is preferably provided for several keys 
for operation efficiency, because fewer screws need to be loosened when 
removing the key 14. 
The case when a player depresses the key 14 at a high speed is now 
described. When the key 14 is quickly depressed, the key 14 swings 
counterclockwise in FIG. 1 centering on the key support 15. Thereby, the 
sliding tape 32 of the wippen 30 is depressed by the actuator 35. Since 
the wippen 30 has a large inertial moment, the sliding tape 32 is 
resiliently deformed and the wippen 30 itself is slightly deformed, to 
store the pressure of the actuator 35. Therefore, the wippen 30 does not 
start swinging immediately. 
Subsequently, in addition to the pressure of the actuator 35, the restoring 
force of the deformed sliding tape 32 and the deformed wippen 30 is 
exerted, so that the wippen 30 starts swinging with force. Accompanying 
the forced swinging of the wippen 30, the jack 44, having an inertial 
moment smaller than that of the wippen 30, immediately slides pushing up 
the hammer 50. As the jack 44 slides, the hammer 50, having an inertial 
moment smaller than that of the wippen 30, immediately starts swinging, is 
let off from the jack 44 and reaches the simulating string striking 
position. Therefore, the characteristics peculiar to an acoustic piano, 
i.e. a touch of a quickly depressed key, its relationship with the 
loudness of a produced electronic sound and a time lag before generating 
the sound can be realized by the wippen 30 in the embodiment. 
The key depression detecting sensor 37 stays at its initial condition (with 
the switches S1 and S2 off), before the wippen 30 starts swinging. When 
the wippen 30 starts swinging with force and reaches the first position, 
the switch S1 turns on. Subsequently, when the wippen 30 reaches the 
second position, the other switch S2 turns on. Subsequently, after the 
hammer 50 swings back, if the key is depressed, the wippen 30 is at a 
position (wippen swing position) shown in FIG. 2, and both the switches S1 
and S2 are on. If the key is released, the wippen 30 is at a position 
shown in FIG. 1 (wippen initial position), and both the switches S1 and S2 
are off. 
Except that the hammer 50 does not strike a string, the function of the 
simulating action mechanism of the embodiment is the same as the action 
mechanism of an acoustic piano. Therefore, a player can obtain from the 
key 14 a touch almost the same as a touch of an acoustic piano. 
When a player depresses the key, the underside of the front end of the 
wippen 30 contacts the key depression detecting sensor 37, turning on or 
off the two switches in the sensor 37. Therefore, the key depression 
timing and velocity can be detected. Based on the detection, a musical 
sound can be generated from an electronic sound source under control of an 
electronic control circuit (not shown) at a timing corresponding to the 
key depression timing with a musical interval corresponding to the 
depressed key and an intensity corresponding to the key depression 
velocity. 
According to the aforementioned first embodiment, the following effects can 
be obtained. 
(1) In the keyboard device 1 of the invention, the small-sized rib 19 
regulates an interval between the rear end of the flat portion 12 (i.e. 
the vicinity of the key support 15) and the key bed 2 to a predetermined 
interval. Since the upper flange portion 21c and the lower flange portion 
22 of the rib 19 can be integrally formed by pressing in a small metallic 
mold, the rib 19 can be manufactured at a low cost. Additionally, the 
accuracy of the rib 19 itself is sufficiently increased. The height of the 
key support 15 is determined by the height of the rear end of the flat 
portion 12 of the chassis 11, i.e. the interval between the upper flange 
portion 21c and the lower flange portion 22 of the rib 19. Therefore, by 
increasing the accuracy of the rib 19, the accuracy in height of the key 
support 15 is also increased. 
(2) The leg portion 13 of the chassis 11 according to the embodiment is a 
reinforcement member extended in the key arrangement direction. Since the 
front end of the rib 19 is fixed to the leg portion 13, even if an 
obliquely downward force is applied from above to the chassis 11, the 
chassis 11 is not easily deformed, and its accuracy is not deviated. 
(3) In the embodiment, the simulating string striking portion 58 of the 
hammer 50 is behind the rear end of the flat portion 12 of the chassis 11. 
The wippen 30 is passed from under the key 14 through the open space 39 
between the rear end of the chassis 11 and the key bed 2 for transmitting 
action of the key 14 via the jack 44 to the hammer 50. In the prior art, 
since the space between the rear end of the chassis and the key bed is 
closed, a hole for passing the wippen 30 or another action transmitting 
member needs to be provided in each hammer. Since the hole is not required 
in the embodiment, the manufacture cost can be advantageously reduced. 
Also, the key 14 and the action mechanism including the hammer 50 can be 
assembled using the open space 39, thereby providing superior operation 
efficiency. 
In the electronic keyboard instrument according to the embodiment, since a 
musical sound is transmitted in accordance with the key depression timing 
detected by the key depression detecting sensor 37 or the like, the height 
of the key support 15 required to be accurate. As aforementioned in the 
paragraph (1), however, since the accuracy in height of the key support 15 
can be sufficiently increased, the requirement can be sufficiently 
satisfied. 
(4) The wippen 30 and the hammer 50 constituting the simulating action 
mechanism are swingably positioned with accuracy on the chassis 11 
provided with the key support 15. Specifically, the wippen 30 provided 
with the jack 44 is attached onto the chassis 11 via the bearing member 33 
for supporting the wippen swing axis 31, and the hammer 50 is attached 
onto the chassis 11 via the center rail 60 provided with the bearing 
member 65 for supporting the hammer swing axis 51. Also, when fixing each 
member on the chassis 11 before disposed on the key bed 2, the key 14 is 
positioned relative to the wippen 30 and the hammer 50, so that when the 
key 14 swings, the wippen 30 swings, the jack 44 swings and moves, then 
the hammer 50 swings centering on the hammer swing axis 51. In this 
manner, the key 14, the wippen 30 and the hammer 50 are precisely 
positioned and fixed on the chassis 11 beforehand, to provide a key stroke 
and a letting-off timing in the same manner as in an acoustic piano. 
Different from the prior art, an intricate operation for separately 
providing and positioning on the key bed the keyboard unit and the action 
unit is unnecessary. In the embodiment, the chassis 11 assembled with the 
key 14, the wippen 30, the hammer 50 and the like can be attached to the 
key bed 2 as it is. Mounting operation is simplified. Also, different from 
the prior art, an intricate operation for adjusting the height of each key 
and each wippen with a capstan screw is unnecessary. According to the 
keyboard device of the embodiment, the mounting on the key bed can be 
easily attained with accuracy. 
(5) Since the center rail 60 is provided in the vicinity of the rear end of 
the key 14 on the chassis 11, the depth dimension of the keyboard device 1 
can be shortened and the entire device can be made compact. 
(6) Since the wippen 30 is swingably supported by the underside of the key 
14 on the chassis 11, a load on the center rail 60 can be reduced as 
compared with the case where the wippen is swingably supported on the 
center rail 60 (refer to the third embodiment described later). 
(7) Since the key depression detecting sensor 37 for detecting key 
depression information in response to swinging of the key 14 is fixed via 
the base 28 onto the chassis 11 before being mounted on the key bed 2, the 
key 14 and the key depression detecting sensor 37 need not to be 
positioned on the key bed 2. Therefore, the mounting on the key bed 2 can 
further be simplified. 
(8) The bearing 16 for supporting the key support 15 is prevented from 
being disengaged from the holes 17 in the chassis 17 by using the center 
rail 60, without providing separate components for fixing the bearing 16. 
Therefore, as compared with the case where the separate components are 
used, a component cost can be reduced. By mounting the center rail 60, the 
bearing 16 can be advantageously prevented from being disengaged without 
attaching the separate components, thereby enhancing operation efficiency. 
(9) The bearing 16 is engaged in the chassis 11 by holding the peripheral 
portion of the holes 17 between the underside of the bearing 16 and the 
L-shaped legs 18. Before the center rail 60 is fixed, the bearing 16 can 
be temporarily fixed in the holes 17 of the chassis 11. Therefore, 
operation efficiency is enhanced. Also, the bearing 16 can be fixed 
relative to the chassis 11 without vertically oscillating. Also, since a 
pair of L-shaped legs 18 are provided in the key back-to-forth direction, 
the bearing 16 is prevented from tilting. 
(10) Since the center rail 60 for supporting the hammer swing axis 51 is 
usually attached behind the key 14, in the embodiment the bearing 16 is 
easily fixed by providing the key support 15 on the rear end of the key 
14, instead of providing the key support 15 around the middle of the key 
14. 
(11) When the key 14 needs to be replaced, in the embodiment the screw 8 
and the center rail 60 need not to be removed to disengage the bearing 16 
from the chassis 11. Specifically, the screw 8 is loosened, and the center 
rail 60 is slid rearward along the elongated hole 61a, so that the bearing 
16 can be detached from the holes 17 in the chassis 11. The efficiency of 
operation for disassembling the key 14 is remarkably enhanced. 
(12) The wippen 30 and the hammer 50 constituting the simulating action 
mechanism is swingably positioned with accuracy and fixed onto the chassis 
11 provided with the key support 15 (or onto the center rail 60 fixed to 
the chassis 11). When assembling, the key 14, the wippen 30 and the hammer 
50 are precisely positioned for providing a positional relationship among 
these components, to provide the same key stroke as in an acoustic piano. 
Therefore, different from the prior art, an intricate operation for 
separately providing and positioning the keyboard unit and the action unit 
on the key bed is unnecessary. In the embodiment the chassis 11 provided 
with the key 14, the wippen 30, the hammer 50 and the like can be mounted 
on the key bed 2 as it is. The mounting operation is remarkably 
simplified. Also, an intricate operation for adjusting the height of each 
key and each wippen with a capstan screw is unnecessary. According to the 
keyboard device of the embodiment, the mounting on the key bed can be 
easily attained with accuracy. 
(13) The regulating felt 66 for regulating action of the jack 44 during 
acting and the hammer cushion 68 for regulating the initial position of 
the hammer 50 are provided on the upper face and the lower face of the 
rail 67, respectively. Cost can be advantageously reduced, as compared 
with the case where the felt and the cushion are provided on separate 
members. 
(14) In the embodiment, the thickness of the regulating felt 66 is 
determined by considering the letting-off timing, while the thickness of 
the hammer cushion 68 is determined by considering the initial position of 
the hammer. When attaching the rail 67 provided with the regulating felt 
66 and the hammer cushion 68 to the center rail 60, by increasing the 
attachment accuracy, the accuracy required for both the members 66 and 68 
can be satisfied. Attachment operation is advantageously simplified as 
compared with the case where both the members 66 and 68 are separately 
attached. Also, since the rail 67 has a simple constitution, the 
attachment accuracy can be easily increased. 
(15) On the chassis 11 for supporting the key support 15, the wippen 30 is 
directly provided, and the hammer 50 and the rail 67 are provided via the 
center rail 60. Specifically, the simulating action mechanism and the 
keyboard are both provided on the chassis 11. By positioning and fixing 
the simulating action mechanism and the keyboard with accuracy on the 
chassis 11 beforehand, an intricate operation for positioning the 
simulating action mechanism and the keyboard on the key bed 2 is 
unnecessary. The mounting on the key bed 2 is remarkably simplified. 
(16) The hammer 50 and the rail 67 are provided on the center rail 60 fixed 
on the chassis 11. Therefore, the hammer cushion 68 provided on the rail 
67 can be easily aligned with the hammer 50, and the initial position of 
the hammer 50 can be easily determined. 
(17) The stop rail portion 63 is provided on the center rail 60, thereby 
obviating the necessity of another member. Therefore, cost can be saved. 
Additionally, by determining the thickness of the stop felt 63a of the 
stop rail portion 63 by considering the simulating string striking 
position and increasing the attachment accuracy of the rail 67, the 
accuracy required for the three members 63, 66 and 68 can be satisfied. 
The attachment operation is simplified as compared with the case where the 
members are individually attached. 
(18) The key depression detecting sensor 37 detects the on and off timings 
of the switches S1 and S2 as the basic information of the performance 
information in response to the action of the wippen 30 for realizing the 
characteristics peculiar to an acoustic piano. Further, an electronic 
control circuit (not shown) prepares the performance information including 
a sound velocity (i.e. sound intensity) based on the on and off timings, 
and controls an electronic sound source to generate a musical sound based 
on the performance information. Therefore, according to the embodiment, a 
touch of a key depressed at high speed, a loudness of a sound produced 
accordingly and a time lag from when the key is depressed until the sound 
is produced can be reproduced in the same manner as in an acoustic piano. 
(19) When the key 14 is depressed from the standstill position (refer to 
FIG. 1) to the full-stroke position (refer to FIG. 2), the wippen 30 
swings from the wippen initial position (refer to FIG. 1) corresponding to 
the standstill position of the key 14 to the wippen swing position (refer 
to FIG. 2) corresponding to the full-stroke position of the key 14. Each 
wippen 30 acts in response to action of each key 14. The key depression 
detecting sensor 37 detects whether or not the wippen 30 has passed the 
first and second positions predetermined between the wippen initial 
position and the wippen swing position. Further, the electronic control 
circuit (not shown) prepares sound stop information as one piece of the 
performance information based on the on and off timings of the key 
depression detecting sensor 37 for detecting the action of each wippen 30 
corresponding to the action of each key 14, to stop sounding. In this 
manner, in addition to the sound velocity, the sound stop information can 
be precisely obtained based on the information detected by the key 
depression detecting sensor 37. Therefore, the necessity of separately 
providing a sensor for obtaining the velocity and a sensor for obtaining 
the sound stop information is obviated, thereby reducing the cost. 
(20) The cushion material 56 covers the rest portion 52, the butt portion 
53 and the catcher portion 54 provided on the hammer 50 in series. 
Different from the case where the portions are individually covered, the 
cushion material doesn't to be cut and placed individually. As a result, 
the cost can be reduced. According to the embodiment, an impact noise can 
be prevented from being generated in the simulating action mechanism at a 
low cost. 
(21) The hammer 50 is provided with the rest portion 52, the butt portion 
53 and the catcher portion 54 on a continuous plane by molding. Therefore, 
the operation efficiency is enhanced when covering the portions 
continuously with the cushion material 56. 
In the embodiment, since the hammer cushion 68 itself has a function of 
absorbing impact, the rest portion 52 of the hammer 50 is not necessarily 
covered with the cushion material 56. However, the rest portion 52 of the 
hammer 50 is formed into a flat face and the butt portion 53 and the 
catcher portion 54 are formed into a curved face by molding. When placing 
the cushion material 56, first one end of the cushion material 56 is 
positioned and attached to the rest portion 52 formed into a flat face, 
then positioned and attached to the butt portion 53 and the catcher 54. In 
this manner, the cushion material 56 can be preferably placed without 
being deviated. 
(22) By using the constitution in which the sliding tape 32 of the wippen 
30 is depressed by the actuator 35 provided on the underside of the key 14 
before the key support 15, the key 14 does not require the portion behind 
the key support 15. Therefore, by cutting away the portion behind the key 
support 15, the length of the keyboard device 1 in the depth direction is 
shortened accordingly, and the entire device can be advantageously made 
compact. 
(23) The wippen swing axis 31 is disposed between the key support 15 of the 
key 14 and the sliding tape 32 of the wippen 30, i.e. before the key 
support 15. Therefore, no space for providing the wippen swing axis 31 is 
required behind the key support 15. The entire device can be 
advantageously made compact accordingly. 
Second Embodiment 
FIG. 3 is a sectional view of a keyboard device according to a second 
embodiment. In FIG. 3, a solid line shows a key release condition, while a 
dotted line shows a simulating string striking condition. The second 
embodiment is the same as the first embodiment, except that the wippen 30 
of the first embodiment is used as a hammer and the center rail 60 is used 
only as a stop rail. Alike constitutional elements are denoted with the 
same reference codes and the description thereof is omitted. 
A hammer 150 of the second embodiment (the action transmitting member of 
the invention) has substantially the same constitution of the wippen 30 of 
the first embodiment. The hammer 150 is swingable centering on a hammer 
swing axis 151, and has on its top face a simulating string striking 
portion 158 with a cushion material placed thereon. A flange portion 161 
of a stop rail 163 is fixed with a screw on the flat portion 12 of the 
chassis 11. The front end of the flange portion 161 is fixed abutting on 
the rear L-shaped leg 18, so that the rear L-shaped leg 18 of the bearing 
16 for supporting the key support 15 of the key 14 is prevented from 
sliding in the corresponding hole 17. Further, the stop rail 163 is 
provided with a stop felt 163a extending in the key arrangement direction. 
In the keyboard device, when the key 14 is depressed, the key 14 swings 
counterclockwise centering on the key support 15 in FIG. 3. Thereby, the 
front end of the hammer 150 is depressed by the actuator 35, and the 
hammer 150 swings counterclockwise centering on the hammer swing axis 151 
as the key 14 swings. Then, the underside of the front end of the hammer 
150 depresses the key depression detecting sensor 37, while the rear end 
of the hammer 150 swings upward. Subsequently, the simulating string 
striking portion 158 of the hammer 150 collides against the stop felt 
163a. When the key 14 is released, the hammer 150 is swung clockwise by 
the weight 41, and the key 14 is accordingly returned to its original 
position. 
Also in the second embodiment, since the chassis 11 provided with the flat 
portion 12 and the legs 13, and also with the rib 19 and the open space 
39, the aforementioned effects in the paragraphs (1)-(3) of the first 
embodiment can be obtained. However, different from the first embodiment, 
the simulating action mechanism is not provided. The letting-off action is 
not attained as in an acoustic piano. A touch of an acoustic piano cannot 
be reproduced like the first embodiment. 
Third Embodiment 
FIG. 4 is a sectional view of a keyboard device of a third embodiment. In 
FIG. 4, a solid line shows a key release condition and a dotted line shows 
a string striking condition. The third embodiment is a keyboard device for 
an acoustic piano, not a keyboard device for an electronic keyboard 
instrument. Therefore, different from the first embodiment, the keyboard 
device is not provided with the key depression detecting sensor 37 or the 
stop rail 63. A hammer 250 is provided with a string striking portion 258 
for actually striking a string, instead of the simulating string striking 
portion 58. The other constitution is the same as the first embodiment. 
Therefore, alike constitutional elements are denoted with the same 
reference codes and the description thereof is omitted. 
In the keyboard device, when a player depresses the key 14 until the hammer 
250 rotates, the wippen 30 and the jack 44 act in the same manner as in 
the first embodiment. However, different from the first embodiment, after 
the letting-off action, a hammer felt placed on the string striking 
portion 258 of the hammer 250 actually strikes a string. After the hammer 
250 swings back, each action element acts in the same manner as in the 
first embodiment. 
Also in the third embodiment, since the chassis 11 is provided with the 
flat portion 12 and the leg potion 13, and also with the rib 19 and the 
open space 39, the aforementioned effects (1)-(3) of the first embodiment 
are obtained. 
In the same manner as the first embodiment, in the third embodiment, by 
molding the hammer 250, the rest portion 52, the butt portion 53 and the 
catcher portion 54 are provided on a continuous plane and are continuously 
covered with the cushion material 56. Therefore, the aforementioned 
effects (20) and (21) of the first embodiment can be obtained. 
Fourth Embodiment 
FIG. 7 is a sectional view of a keyboard device according to a fourth 
embodiment. In the same manner as the first embodiment, the fourth 
embodiment is applied to an electronic keyboard instrument. The fourth 
embodiment is different from the first embodiment, in that the wippen is 
not attached directly to the chassis, and is attached to the center rail. 
The same elements as those of the first embodiment are denoted with the 
same reference codes and the description thereof is omitted. Although an 
action lever 360 is similar to the wippen 30 of the first embodiment, the 
action lever 360 functions differently. 
A wippen 330 of the fourth embodiment has a wippen swing axis 331 on its 
front end. The wippen swing axis 331 is swingably supported in the same 
manner as the hammer 50, by a substantially U-shaped bearing member 335 
inserted in a square hole in the rising portion 62 of the center rail 60. 
The bearing member 335 is precisely positioned and attached onto the 
center rail 60. 
The wippen 330 is provided with the bearing portion 42 for supporting the 
jack rotation axis 45 and the back check 43 for receiving the swung back 
hammer 50, which are integrally formed with accuracy. The jack tail 47 of 
the jack 44 is connected with the wippen 330 via the compression coil 
spring 46. 
The front end of the action lever 360 has a lever swing axis 361 supported 
via the bearing member 33 on the chassis 11 in the same manner as the 
wippen 30 of the first embodiment. Also, below the front end of the action 
lever 360, the key depression detecting sensor 37 is provided in the same 
manner as the first embodiment. The rear end of the action lever 360 is 
provided with a push button 362 for abutting on the underside of the 
wippen 330. 
In the keyboard device, when the key 14 is depressed, the key 14 swings 
centering on the key support 15 counterclockwise in FIG. 7. Thereby, the 
front end of the action lever 360 is depressed by the actuator 35, the 
action lever 360 swings centering on the lever swing axis 361 
counterclockwise, the underside of the front end of the action lever 360 
depresses the key depression detecting sensor 37, and the rear end of the 
action lever 360 swings upward. Then, the wippen 330 swingably supported 
by the center rail 60 swings counterclockwise. Subsequently, the jack 44 
and the hammer 50 act in the same manner as in the first embodiment, 
therefore further description is omitted. 
The wippen 330 and the hammer 50 constituting the simulating action 
mechanism of the fourth embodiment are swingably positioned and attached 
with accuracy on the chassis 11. The wippen 330 and the hammer 50 are both 
attached via the center rail 60 to the chassis 11. When attaching, the key 
14, the action lever 360, the wippen 330 and the hammer 50 are precisely 
positioned, so as to provide a positional relationship thereamong for 
reproducing a key stroke of an acoustic piano. 
According to the fourth embodiment, the aforementioned effects (4), (5) and 
(7) of the first embodiment are provided. 
Fifth Embodiment 
FIG. 12 is a sectional view of a keyboard device according to a fifth 
embodiment. In FIG. 12, a solid line shows a key release condition and a 
dotted line shows a simulating string striking condition. FIG. 13 is a 
partial enlarged view of FIG. 12. FIGS. 12 and 13 show a white key. A 
black key is the same as the white key except the structure of the key 
itself. 
In the keyboard device of the fifth embodiment, a chassis comprises of 
three members: a chassis front member 111; a chassis intermediate member 
112 and a chassis rear member 113. The members 111-113 are supported with 
predetermined heights by a rib 119 mounted on the top face of the key bed 
2, respectively. The rib 119 is extended in the key back-to-forth 
direction (in the right-to-left direction in FIG. 12, the same in the 
following). The chassis front member 111 is provided with a cushion 124 
for abutting on the underside of the front end of a wooden key 114, and a 
key guide portion 127 inserted in a hollow portion in the front end of the 
key 114. On the chassis intermediate member 112, a balance pin 115 is 
built for the key 114. The key 114 can swing centering on the balance pin 
115. The chassis rear member 113 is provided with a cushion 126 for 
abutting on the underside of the rear end of the key 114. 
On the rear end of the rib 119, a vertical rail 116 is fixed with a screw 
and extended substantially vertical to the key bed 2 and in the key 
arrangement direction (perpendicular to a sheet face of FIG. 12, the same 
in the following). A center rail 160 is fixed with a screw and connected 
via a connecting rib 117 to the vertical rail 116. 
On the vertical rail 116, a wippen swing axis 131 of a wippen 130 is 
swingably supported by a substantially U-shaped bearing member 133 
inserted in a square hole in the vertical rail 116. The bearing member 133 
is provided with a bearing member fixing plate 134 for covering the wippen 
swing axis 131. The bearing member fixing plate 134 and the bearing member 
133 are fixed with the same screw to the vertical rail 116 like 
cantilevers. The wippen swing axis 131 is prevented by the bearing member 
fixing plate 134 from being disengaged from the bearing member 133. The 
bearing member 133 is precisely positioned and attached onto the vertical 
rail 116. The underside of the rear end of the wippen 130 is provided with 
two capstan buttons 132 for abutting on the top face of the rear end of 
the key 114. 
Behind the key 114, a base 128 is disposed substantially parallel with the 
vertical rail 116. On the base 128, a key depression detecting sensor 137 
is provided opposed to a depressing portion 135 of the wippen 130. The key 
depression detecting sensor 137 has substantially the same function as 
that of the key depression detecting sensor 37 of the first embodiment, 
and is precisely positioned on the base 128 by considering the positional 
relationship with the key 114 and the wippen 130. 
On the front end of the wippen 130, a balancing weight 141 is provided, the 
jack rotation axis 45 of the jack 44 (the same as that of the first 
embodiment) is supported, and a back check 143 is provided for receiving 
the swung back hammer 50 (the same as that of the first embodiment). The 
jack tail 47 of the jack 44 is connected via the compression coil spring 
46 (see FIG. 12) to the wippen 130 in the same manner as the first 
embodiment. 
The center rail 160 fixed to the connecting rib 117 is extended 
substantially vertical to the key bed 2 and in the key arrangement 
direction. The center rail 160 is provided with a stop rail portion 163 
extending up obliquely forward. On the underside of the stop rail portion 
163 is placed a stop felt 163a. 
As shown in FIG. 13, the substantially L-shaped rail 67 is fixed with a 
screw to the center rail 160 below the hammer swing axis 51 in the same 
manner as in the first embodiment. The rail 67 has the hammer cushion 68 
on its top face and the regulating felt 66 on its underside in the same 
manner as in the first embodiment. The hammer 50 has the same constitution 
as that of the first embodiment. In the same manner as in the first 
embodiment, the hammer swing axis 51 is swingably supported by the center 
rail 160. Each element of the hammer 50 is the same as that of the first 
embodiment, and denoted with the same reference codes, therefore further 
description is omitted. 
In the keyboard device of the fifth embodiment having the aforementioned 
constitution, when the key is not depressed, as shown in FIG. 12, the 
weight 141 on the front end of the wippen 130 and the like exert a force 
in the counterclockwise direction in FIG. 12. The force is applied to the 
rear end of the key 114, whose front end tries to swing upward. However, 
since the underside of the rear end of the key 114 abuts on the cushion 
126, the key 114 is inhibited from swinging. 
When a player depresses the key 114, the key 114 swings centering on the 
balance pin 115 provided substantially on the middle of the key 114 
counterclockwise in FIG. 12. Thereby, the wippen 130 is depressed via the 
capstan buttons 132, and swings centering on the wippen swing axis 131 
clockwise. When the depressing portion 135 depresses the key depression 
detecting sensor 137, the front end of the wippen 130 swings upward. Then, 
the jack 44 accompanies the swinging wippen 130, rises to push up the butt 
portion 53 of the hammer 50 and swings clockwise relative to the wippen 
130. The subsequent action is the same as in the first embodiment, except 
that the rotation direction of the jack and the hammer in FIG. 12 is in 
reverse to the rotation direction of the first embodiment shown in FIGS. 1 
and 2. Further description is therefore omitted. 
The action when a player depresses the key 114 at high speed is now 
described. When depressed at high speed, the key 114 swings centering on 
the balance pin 115 counterclockwise in FIG. 12. Thereby, the capstan 
buttons 132 of the wippen 130 are depressed by a cushion 138 placed on the 
key 114. Since the wippen 130 has a large inertial moment, the cushion 138 
is resiliently deformed and the wippen 130 itself is slightly deformed to 
store pressure. Therefore, the wippen 130 does not immediately start 
swinging. 
Subsequently, in addition to the force for pushing up the capstan buttons 
132 of the wippen 130, the restoring force of the deformed cushion 138 and 
the deformed wippen 130 is exerted, so that the wippen 130 starts swinging 
with force. Accompanying the forced swinging of the wippen 130, the jack 
44, having an inertial moment smaller than that of the wippen 130, 
immediately swings pushing up the hammer 50. As the jack 44 swings, the 
hammer 50, having an inertial moment smaller than that of the wippen 130, 
immediately starts swinging, is let off from the jack 44 and reaches the 
simulating string striking position. Therefore, the characteristics 
peculiar to an acoustic piano, i.e. a touch of a quickly depressed key, 
its relationship with the loudness of a produced electronic sound and a 
time lag from when the key is depressed until the sound is generated can 
be realized by the wippen 130 in the embodiment. 
The key depression detecting sensor 137 stays at its initial condition 
(with both the switches off), before the wippen 130 starts swinging. After 
the wippen 130 starts swinging with force, the switches turn on 
successively. Subsequently, after the hammer 50 swings back, if the key is 
depressed, both the switches are on. If the key is released, both the 
switches are off. Therefore, the sound stop information can be precisely 
obtained based on the on and off timings of the switches. 
According to the keyboard device of the fifth embodiment, the 
aforementioned effects (1), (2), (13)-(17) of the first embodiment can be 
obtained. 
Sixth Embodiment 
FIG. 14 is a partial sectional view of a keyboard device of a sixth 
embodiment. In FIG. 14, a solid line shows a key release condition and a 
dotted line shows a string striking condition. The keyboard device of the 
sixth embodiment is applied to an acoustic piano, not to an electronic 
keyboard instrument. Therefore, the sixth embodiment is different from the 
fifth embodiment, in that the key depression detecting sensor 137 and the 
stop rail portion 163 are not provided in the same manner as the third 
embodiment, and a hammer 250 (the same as in the third embodiment) is 
provided with a string striking portion 258 for actually striking a 
string. The other respects are the same as in the fifth embodiment, 
denoted with the same reference codes, therefore further description is 
omitted. FIG. 14 is a partial sectional view, not showing the keyboard, 
the chassis, the rib and the like, which have the same constitution as in 
the fifth embodiment. 
In the keyboard device of the sixth embodiment, when a player depresses the 
key 114, each action member (the wippen 130 and the jack 44) acts in the 
same manner as in the fifth embodiment, until the hammer 250 rotates. 
After the letting-off action, a hammer felt placed on the string striking 
portion 258 of the hammer 250 actually strikes a string. After the hammer 
250 swings back, each action element acts in the same manner as in the 
fifth embodiment. According to the sixth embodiment, the aforementioned 
effects (13)-(16) can be obtained. 
Seventh Embodiment 
FIG. 17 is a sectional view of a keyboard device according to a seventh 
embodiment. In FIG. 17, a solid line shows a key release condition and a 
two-dotted line shows a string striking condition. 
The keyboard device of the seventh embodiment is provided with the action 
mechanism of the prior-art keyboard device of FIG. 8: the wippen 830, the 
jack 844, the hammer 850 and the hammer stopper 863. 
A key support 915 of a key 914 is supported by a bearing fixed on a chassis 
911. The key 914 has the portion behind the key support 915 cut away. On 
the underside of the key 914 before the key support 915, an actuator 935 
abuts via an opening 925 in the chassis 911 on a felt f or depressed 
portion of the wippen 830. Also below the key 914 disposed is a key 
depression detecting sensor 837. 
A wippen axis WC of the wippen 830 is supported before the key support 915 
under the chassis 911. The wippen 830 has the felt f on its front end and 
a jack axis 845 on its rear end. The wippen axis WC is positioned between 
the felt f and the key support 915. 
The operation of the keyboard device according to the seventh embodiment is 
briefly described. When the key 914 is depressed, the actuator 935 
provided on the underside of the key 914 depresses the felt f of the 
wippen 830. Then, the wippen 830 swings centering on the wippen axis WC 
clockwise in FIG. 17, and the jack 844 supported by the jack axis 845 of 
the wippen 830 pushes up the butt 850a of the hammer 850. The hammer 850 
starts swinging centering on the hammer axis 851 clockwise. After the jack 
tail 847 abuts on the regulating felt 866, the jack 844 immediately swings 
counterclockwise and moves apart (lets off) from the butt 850a. Then, the 
hammer 850 starts inertial movement. Subsequently, the hammer 850 collides 
against the hammer stopper 863 (as shown by a two-dotted line in FIG. 17), 
and swings back. 
In the keyboard device of the seventh embodiment, the configuration of the 
key 914 is the same as that of the first embodiment. The positional 
relationship of the key support 915 of the key 914 with the felt f or 
depressed portion of the wippen 830, the wippen axis WC and the jack axis 
845 is the same as in the first embodiment. Therefore, the aforementioned 
effects (18) and (19) of the first embodiment can be obtained. 
Other Embodiments 
The constitution of the chassis 11 and the rib 19 can be applied, for 
example, to the keyboard device of FIG. 5 or FIG. 6. In either case, the 
aforementioned effects (1)-(3) of the first embodiment can be obtained. 
When the constitution is applied to the keyboard device of FIG. 5, 
however, the aforementioned effects (1) and (2) of the first embodiment 
can be provided, but the effect (3) is not provided, because the hammer is 
not provided. 
Also in each of the aforementioned embodiments, the chassis is, for 
example, divided into a chassis front member (provided with longitudinal 
felts 26a and 26b) and a chassis rear member (provided with the bearing 
16). The chassis members are interconnected with the rib 19. In this case, 
the effects similar to those of the first embodiment can be obtained. 
Also in the aforementioned embodiments, the inertial moment of the wippen 
30 or 130 may be designed larger than the inertial moment of the key 14 or 
114. The released key 14 or 114 is given a force by the wippen 30 or 130 
receiving the weight of the hammer 50 and the like, so that the front end 
of the key rotates upward. Thereby, the key is held at its standstill 
position. In this case, when the wippen 30 or 130 has a larger inertial 
moment than the key 14 or 114, the key 14 or 114 can be effectively held 
at its standstill position only by the wippen 30 or 130, even when the 
jack 44 and the hammer 50 have a compact structure and a remarkably small 
inertial moment. 
Further in the aforementioned embodiments, the key depression detecting 
sensor 37 or 137 uses contact type button switches. Alternatively, a 
contact type leaf switch or a non-contact type photo switch can be used. 
Here, the leaf switch has a movable contact point formed of a spring plate 
between two opposed fixed contact points. The movable contact point is 
usually in contact with one of the fixed contact points (used as the first 
switch S1), and is placed by external force in contact with the other 
fixed contact point (used as the second switch S2). When the external 
force is eliminated, the movable contact point is again in contact with 
the first fixed contact point. The photo switch is formed by providing a 
light emitting element (e.g. an infrared emission diode) on one of its two 
opposed faces and a light receiving element (e.g. a photo transistor) on 
the other face. Two pairs of such elements are provided, and a light path 
is formed between each light emitting element and each light receiving 
element. The photo switch is a photo interrupter for detecting whether the 
light is interrupted or transmitted in the light path. Light is 
interrupted or transmitted in the light path by a stepped shutter. 
In the aforementioned embodiments, the key 14, 114 or 914 has the portion 
behind the key support 15, 115 or 915 cut away or removed. The portion 
behind the key support 15, 115 or 915 can be remained by an appropriate 
length as required.