Yamaha G10C Manual de usuario descargar pdf (Pagina 2)

EP 0 585 798 B1

Description

FIELD OF THE INVENTION

This invention relates

an upright piano

and,

particularly,

a key

action mechanism

incorporated

the

upright piano.

DESCRIPTION OF THE RELATED ART

typical example

of the

key

action mechanism is

disclosed,

for

example,

Japanese Utility

Model

Appli-

cation

laid-open (Kokai)

No. 57-30791

in EP-A-0 229

746,

and the

prior

art

key

action mechanism disclosed

therein aims

improvement

response

characteristics

a repetition or a quick fingering

such

tremolo.

The

prior

art

key

action mechanism is

provided

association with

a key

and with

hammer

assembly

for

striking a string,

and

capstan

button is

upright

the

rear

end

portion

of the

key.

The

prior

art

key

action

mechanism

comprises a whippen assembly swingably

supported by a stationary

action rail and

upwardly

pushed by

the

capstan

button,

a jack swingably

support-

the

whippen assembly, a compression

coil

spring

inserted between the

whippen assembly

and the

toe

the

jack, a

butt

rotatably supported by

the

stationary ac-

tion rail and connected with the hammer

assembly, a

regulating

button for

defining a

release of the

jack, a

catcher

backwardly projecting

from the

butt,

back

check

projecting

from the

whippen assembly

and

op-

posed

the

catcher,

and

a spring

wire

backwardly

pro-

jecting

from the butt. The butt is

urged by a

butt

spring

direction

space

from the associated

strings.

While the

key

staying

rest

position,

the

com-

pression

coil

spring

allows the

jack

stay

the initial

position

under the

butt,

and the

toe

of the

jack

spaced

apart

from the

regulating

button,

and the back check is

also

spaced

apart

from the catcher.

When

a player depresses

the

key,

the

capstan

but-

ton

upwardly depresses

the

whippen assembly,

and the

whippen assembly

is driven for rotation. As the

jack

swingably supported on

the

whippen assembly,

the

jack

pushes

the butt with the rotation of the

whippen assem-

bly,

and drives the butt

and,

accordingly,

the hammer

assembly

for rotation toward the

string.

However,

when

the

toe

of the

jack

brought

into

contact

with the

regu-

lating

button,

the

jack

starts

rotating

release from the

butt,

and kicks the butt. As

result,

the hammer

assem-

bly

rushes toward the

string,

and strikes the

string

for

producing a piano

sound.

The hammer

assembly

rebounds from the

string,

and

backwardly

rotates.

The butt

spring supplements

the rotation of the hammer

assembly.

The catcher

moves

closer

the back

check,

and the

spring

wire is

brought

into

contact

with the

top

surface of the back

check before the catcher is

brought

into

contact

with the

back check. As the hammer

assembly

continues

ro-

tate

backwardly

until it is checked

the back

check,

the

spring

wire is

deformed,

and the deformation

causes

the elastic force

urge

the butt in the direction

the

string.

After the

contact

of the

spring

wire with the

top

surface of the back

check,

the catcher is

brought

into

contact

with the back check. As

result,

when the

key

slightly

lifted and the catcher is released from the back

check,

the butt

and,

accordingly,

the hammer

assembly

slightly

advance toward the

string.

The elastic force

caused

the

spring

wire

slightly

lifts the

butt,

and the

butt thus lifted allows the

jack

easily move

thereunder.

This

means

that the

key

action mechanism

gets

ready

for

response

the

key depressing,

and the

spring

wire

improves

the

response

characteristics

the

quick

fingering.

However,

the

prior

art

key

action mechanism thus

arranged

encounters

various

problems.

First,

when

a player softly depresses

the

key

for

pro-

ducing a pianissimo

sound,

the hammer

weakly re-

bounds from the

string.

Therefore,

the

torque

back-

wardly rotating

the butt

can

not

overcome

the

torque

produced by

the

spring

wire for

urging

the butt toward

the

string,

the hammer

assembly

is liable

to return

with-

out

any

contact

between the back check and the catcher

for

striking

the

string again.

Another

problem

is the loss of

sound. Before the

jack

is released from the

butt,

the

spring

wire

must

brought

into

contact

with the

top

surface of the back

check,

that the

jack can

return

under the butt when

the catcher is released from the back check due

the

key slightly

lifted. And elastic force caused

the

spring

wire is

expected

larger

than that of the butt

spring

so as

slightly

lift the butt. When the

player depresses

the

key slowly,

the back check is

upwardly

moved

to-

gether

with the

whippen assembly,

and

pushes

the

spring

wire

upwardly

after the

jack

is released from the

butt, and,

accordingly,

the

spring

wire

urges

the butt

to-

ward the

string.

In this

case,

the elastic force of the

spring

wire

causes

the butt

and,

accordingly,

the ham-

mer assembly

to rotate

forcibly

toward the

string,

and

presses

the hammer

against

the

string.

No vibration

takes

place on

the

string,

and the

expected

sound is lost

due

the hammer

assembly pressed against

the

string.

Yet another

problem

is encountered in the

prior

art

key

action mechanism in

regulating.

In the

regulating,

especially, adjusting

the

regulating

button for

ordi-

nary

acoustic

piano,

while

tuner

slowly depressing

a key,

the

jack

is released from the butt

a predeter-

mined

point,

and the hammer

slightly

returns

thereafter.

At the

timing

when the hammer

slightly returns,

the

tuner

adjusts

the distance between the hammer head and the

string

a predetermined

value.

However,

described

hereinbefore,

the

prior

art

key

action mechanism is

equipped

with the

spring

wire,

and the

spring

wire is still

held in

contact

with the back check after the release of

the

jack.

This

means

that the

tuner

can

not

discriminate

the

timing

when the distance should be

adjusted

the

predetermined

value,

because the hammer

urged

to-

ward the

string by

the

spring

wire,

not

the

jack, can

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EP 0 585 798 B1 12
IP 0 585 798 B1 20

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