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11
IB-65100
Equipment Description
b) Main Spring Charging System
The charging motor (Figure 6, i), located
on the bottom right of the base pan, is
assembled to the circuit breaker by a
bracket that is bolted to the base pan.
The charging motor drive shaft inserts
into the eccentric drive shaft. The
eccentric drive shaft is supported by
needle roller bearings in the mechanism
frame side sheets and transmits the
motor torque to the right side of the
mechanism.
When the charging motor is energized,
the eccentric drive shaft rotates and
causes the pawl support arms to pivot
about the camshaft (Figure 7, p). The
drive pawl (Figure 7, m), which is
supported by the arms, engages with
the ratchet wheel and drives the ratchet
wheel one tooth at a time. To prevent
backwards motion of the ratchet wheel,
a spring-loaded holding pawl is used
to latch the ratchet wheel after each
advance from the drive pawl.
To ensure correct synchronization of
the drive and holding pawl, the position
of the holding pawl support arms are
adjusted by the holding pawl adjusting
eccentric (Figure 7, f ), located at the
left front of the mechanism. When the
mechanism is operated manually, the
top pawl becomes the drive pawl and
the bottom pawl becomes the holding
pawl.
As the ratchet wheel (Figure 7, i) rotates,
projections from its side faces engage
the drive plates. The drive plates are
attached to the camshaft, and cause
the camshaft to rotate. Crank arms
(Figure 7, h) are attached to the ends of
the camshaft. Crank pins (Figure 7, g)
are assembled to the crank arms, which
point outward. The crank arms engage
the bottom ends of the connecting
rods (Figure 6, e). The pins that project
from the spring yoke, which straddles
the main closing spring, engage the
top ends of the connecting rods. As
the camshaft rotates the connecting
rods pull the spring yoke downward,
compressing the main closing spring.
The ratchet wheel drives the camshaft
so that the connecting rods go down
to their lowest position, and then start
to move upward. At a certain point,
the spring force overcomes friction
and resistance and start to rotate the
camshaft. At the same time, the pawls
are uncoupled from the ratchet wheel
by the pawl lift plate (Figure 7, j), and
the motor cut-off switch is operated.
The motor cut-off switch (Figure 7, t),
located to the right of the mechanism, is
operated by the spring charge indicator
and motor cutoff cam (Figure 7, q). The
spring charge indicator (Figure 1, o)
displays that the mechanism is charged.
The camshaft (Figure 7, p) is restrained
by the close latch arm engaging against
the close latch shaft. The main closing
cam, located between the mechanism
side sheets, is in a position where the
fundamental linkage can move to the
reset position.
