Hyd-Mech S-20H, Operations & Maintenance Manua

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Pg 12
S22Hna 2002a
BLADE SPEED SELECTION
The blade speed of the S-20 can be changed between four
different speeds. The speed is determined by the ratio of the pulleys
that drive the V belt. The four pulley sets give the optional speeds of
90, 140, 220, and 310 Surface Feet Per Minute.
The label shown to the right is found on the rear side of the head
near the drive motor.
CHANGING BELT POSITION
To change the blade speed of the S-20 it is necessary to release the V belt
tension and move the V belt to another set of pulley grooves. The tension on the V
belt is maintained by means of a toggle handle assembly that moves the motor. As
the handle is moved to its locking position the motor is driven tight against the V
belt. The toggle handle can be adjusted to change the effective tension on the V
belt by setting the lock nuts which mount the handle to the motor mount plate. The
motor mount plate pivots on rubber bushings that support the motor.
VARIABLE SPEED CONTROL OPTION
Variable blade speed can be adjusted infinitely between 65 and 330 SMM
Adjustment should be made only when the blade is running. Clockwise rotation of the
knob increases blade speed while counter clockwise rotation decreases blade speed.
It is recommended to occasionally run the speed adjustor through it’s full range.
This will help in maintaining the pulley system. It is also recommended that if the
same speed is used for long periods, then a minor adjustment should be made,eg; 200
SFM should be run at 190 or 210 SFM for part of the time. This will help in reducing
wear grooves and keep the speed adjustment smooth.
HEAD SWING and BREAK
An integral function of the S-20 is the ability to make
mitred cuts at angles between 90
O
and 45
O
(or 30
O
optional). The Head swing of the S-20 is easily changed to
set a different cutting angle by first releasing the angle
brake lever, and then manually moving the Head to the
cutting angle desired. An angle scale with a pointer in
clear view of the saw operator allows for accurate setting
of the cutting angle. The angle brake lever is then locked
in position by forcing it into the down position. It should be
noted that the angle brake should be locked into position
whenever cutting with the saw. The photo illustrates the
angle brake in the locked position at 65
O
. To set the saw to
the 90
O
position, the Head ( in the fully down position ) is
moved until the frame meets the 90
O
stop bolt which is
located in the coolant tray at the drive end of the head.
Head swing scale and angle brake (locked).
Drive belt tensioning lever.
Variable blade speed
adjustor.
APPROXIMATE BLADE SPEED
Ratio 1 2 3 4
Ft/Min 90 140 220 310