Timex DYNABEAT 253 - Page 13

Operation of the Model 253 Movement
INDEX WHfEL
MAGNET
8
MAGNET
8
253.12
•
FIGURE J
MAGNET
c
DRAW LEVER
IMPULSE
PIN
1
The index wheel assembly is
driven as follows:
Figure J (shown after impulse
pin leaves fork).
The impulse pin on the balance
assembly, when moving clock-
wise, engages with the fork on
the index lever and moves the
lever counter-clockwise .
Pin "D" on the index lever, en-
gages with the index wheel and
moves the index wheel clock-
wise approximately 3/4 of one
tooth. The three magnets
(round pins mounted in the
plate assembly and labeled A,
B and C in the sketches, attract
the tips of the index wheel
teeth and move the wheel
clockwise the remammg V4
tooth. Magnet C also attracts
the draw lever on the index
lever and holds the draw lever
in position until moved by the
impulse pin.
Figure I< (shown after impulse
pin leaves fork).
The impulse pin on the balance
assembly, when moving coun-
terclockwise, engages with the
fork on the lever and moves
the index lever clockwise. Pin
"D" on the index lever moves
BALANCE HAFFout of engagement with the in-
INDEX WHEEL
IMPULSE PIN
FIGURE K
dex wheel and pin "E" moves
into engagement with the index
wheel. If the index wheel is not
positioned correctly by the mag-
nets, pin "E" turns the index
wheel to the correct position so
that the next engagement of
pin "D" (moving counterclock-
wise) will advance the index
wheel clockwise .
Clockwise rotation of the in-
dex wheel drives the movement
gear train.