Toro VACU-POWER Service Manual page 64

SECTION
5
ZONE START BRAKES
Introduction
In
1982
the federal government mandated that all
consumer walk behind mowers with a cut of 63.5 cm
(25")
or
less be equipped with safety devices. There
are two primary criteria which these devices must
meet:
1.
A two step operation must be performed in order
to get the blade turning.
2. The blade must come to a stop within three
seconds of the operator leaving the operator's
position.
One of the ways The Toro Company met these
requirements was with the 'zone start system', This
system utilizes a kill switch and brake which stops the
engine when the operator releases the control bar. The
two step blade engagement criteria is met by requiring
the operator to first raise the control bar, and second,
pull the recoil rope from the operator's position. See
Figure 102. Notice that the end of the recoil rope is up
near the operator's position just ahead of the control
bar. This allows the operator to start and operate the
unit without ever leaving the operator's position.
G R O U N D
STARTER
RECOIL
Figure
102
The Toro Company uses two different zone start
systems. The one used on the Tecumseh 2-cycle
engine uses a push button-type switch and a
plunger-type flywheel brake mechanism. The other
uses a spring steel kill switch and a pivoting type brake
mechanism. This style zone start brake
is used on Toro
overhead valve and 2-cycle engines.
The plunger style brake will be discussed first and the
later part of this section will be devoted to the pivoting
style zone start brake.
Vacu-Power Mower
59
PLUNGER STYLE ZONE START BRAKE
Plunger Style Zone Start Brake Operation
There are four key components that comprise the
plunger type zone start brake: the control bar, the
brake cable, the kill switch and the brake. See Figure
103.
Figure
103
The control bar is the source of operator input. When
the control bar is lifted past a point
10
cm
(43
below
the handle, the engine will run, and the brake is not in
contact with the flywheel. When the control bar is
released, the ignition coil is grounded and the brake is
engaged.
The brake cable transfers control inputs from the
operator down to the brake and kill switch on the
engine. The cable is adjustable only at the upper end.
There is no cable adjustment at the engine end. See
Figure
104.
Figure
104
Zone Start Brakes