Fly-Back Safety Mechanism - Seiko 6138A Manual

6f 3BA Operation of Chronograph Meehanism
ヽ
一
Resetting
1. Resetting of the chronograph
minute hand and second hand
When pressing the second but-
ton, the force is transmitted'to
fly-back lever - intermediate
fly-back lever - hammer, and
the hammer strikes the minute
heart and the second heart to
reset the hands to "0" position.
2. Resetting of the chronograph
hour hand
Simultaneously with the above,
the fly-back
lever presses the
hour fly-back lever and the force
is transmitted to the hour ham-
mer to reset the chronograph
hour hand to "0" position. At
this moment, the intermediate
hour recording wheel stop lever
revolves in the -
direction by
action of the hour hammer pin,
and the hour recording wheel is
released. When the second but-
ton is released, the chronograph
hour hand returns to a stopped
condition.
Resetting of chronograph minute hand and second hand
ntermediate fly-back lever
l l ar w he el
Second heart
Fig.17
Intermediate hour
wheel stop lever
'
S∝ ° nd button
Minute heart
Resetting of chronograph hour hand
H o ur h am m er
Hour hamrneipin
Hour heart
F!y‐ back lever
Hour f ly-lcack
lever
Fly-back lever
Fly‐ back safety mechanisln
This mechanism protects the
movement frorn the shock generated
by the sθ θ ο ' ご わ ' ' ο . End portions
of the力 α " 7' η θ "and the' η ' θ /"θ σ Jα ' θ
/7y― bα θ た ' θ ッ θ " are located outside
the column du
ng starting condi―
tion. When the sθ θ ο η ご b
' ' Ott is
depressed, the end portion of the
J' ' θ " θ グ Ji2'
θ ノノ ‐ わ α θ た Jθ ッ θ " slips
among the columns of the ρ " ι α "
w力θ θ ' (as shOWn in Fig.18),and the
force is not translnitted beyond the
力 α " ッ ηθ た On the other hand, the
力 ο " 力 α " 2' η θ " dOes not move be―
cause the pin located on its tip
strikes the Jκ '
̀'
θ diα ' θ ttο "" θ θ OrJ―
J" g" 力 θ
̀'
s' ο ρ た ソ θ " .At this mo―
ment, momentum of the sθ ε ο " ご
b ' ' 0" is absorbed by a sprihging
chaTacteristic of the ttο 夕 " 'ン ‐ bα ε た
' θ ν
̀た
Safety action is exhibited by
integration of thc above‐Inentioned
OperatiOns.
Hour ham me r pi n
Intermediate
hour recording wheel stop
( C ol um n l
P i l l ar w h ee l
Fig.18
Hour hammer
＼
Second button
. Hour f ly-back lever
D
艤
＼
‑6138A‑8‑