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In position B, following the action of ignition
key on instrument panel, the current flows from
the
battery thru coupling coil and solenoid
retaining coil.
The
pinion, which in
this
type
of motors can slide together
with
all coupling
device along a variable pitch thread on
rotor
shaft, is thrust towards outside by the coupling
lever
in
such a measure as
to engage the
flywheel
ring
gear.
Coupling lever
is controlled
by
solenoid keeper.
In position C, owing to the shifting of the
solenoid
keeper, the movable contact atta-
ched to same
closes
the switch
contacts
and
the motor field
windings
are then run thru
by main current.
Motor
rotor begins to
ro-
tate
and the pinion,
which
so far couldn't ro-
tate owing
to the mechanical resistance of
the
flywheel ring gear, screws itself along rotorshaft
thread,
thus compressing
release
spring, and
thrusts
itself until
full engagement
of
its
teeth
and ring gear teeth
is
attained. As
soon
as the
pinion gets
in
touch
with
suitable limit stop on
rotor shaft, positive coupling
of
pinion and rotor
is obtained and flywheel is then
driven by
starter motor.
If after the engine
is started
the
flywheel
speed
exceeds the pinion speed, this
is
disengaged
from rotor shaft by means of
the
roller freewheel
device,
and remains
engaged to the flywheel
until ignition key is released
by
rider and cou-
pling lever is shifted back to rest position by
keeper return spring. Without
the
freewheel
devi-
ce both pinion and rotor
would
be driven to
whirling
speed,
owing to the high flywheel-
pinion
ratio, thus risking
rotor
to
get shattered
by centrifugal force.
Also
in
this motor a disc brake
device
allows
a rapid
stoppage
of rotor.
This
will avoid da-
mage
to
pinion
and ring gear teeth, as
it
would
happen
if,
failing
a
first engine
starting,
the
rider should
try the next starting before the
rotor is still.
During this
phase (posltlon C)
the
keeper is retained
by
the
action
of retaining
coit only.
The
coupling coil,
short~circuited
,
is
cut off.
Position 0
shows the
possibility
that
the
pinion, during its
advancement,
does not
engage
the ring gear because the pinion teeth
,
even if provided with
bevel
,
get frontally stuck
against
ring gear
teeth, thus
preventing
coupling
96
"
"
Fig. 116/
1 -
Wiring diagram
.
Be
:
Field
coil.
Bt
;
Battery.
e
:
electromagnet.
Pu
;
Ignition
key.
M
;
Ground.
from being attained. In this case the switch
contacts
can close all the
same,
being the
coupling
lever
elastically
connected to the pi-
nion Ihru the
coupling
spring. As soon as the
roto
r
will
begin
10
rotate,
the pinion, pushed by
coupling
spring,
will
at once engage flywheel
ring gear.
Operating features of this
coupling
device will
be
more easily understood by looking at Fig.
119, which shows a cutaway
view
of same. As
to
wiring diagram
,
refer to
Fig.
118/1.
Fig.
119
-
Cutaway
vi
ew
of the thrust-screw
combined coupling device.
1
I
1
j
1.
Control lever -
2.
Release spring - 3. Release
spring hous-
Ing
ring
-
4. Sleeve
-
5.
Coupling
spring -
6.
Coupling hub -
7.
Flywheel ring gear· 8. Pinion gear - 9. Roller freewheel.
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