Alamo MACHETE Product Service Manual page 65

PUMP CIRCUIT - MOTOR ENGAGE
Note:
The Servo Control System, (Changed see "Note" on Previous Page)
Movement of the Variable Displacement Pump Control Lever (Figure 40) starts pump Output. As
Lever is rotated, it moves the Spring centered Servo Control Spool first. Movement of the Spool allows
Charge Pump Oil past the Spool to one side of the Servo Piston (Figure 40). The Pressurized Servo Piston
pushed against the Camplate (figure 40) causes the Camplate to rotate to a Pre-Set Angle. Oil from the
opposite end of the Servo Piston is exhausted to the Pump Housing through the Control Valve Spool.
When the Control Lever (Solenoid & Block on Current Models) is returned to the Neutral position, The
Spool centers itself, allowing the Pressure on both ends of the Servo Piston to equalize. The Piston and.
Camplate return to a Neutral position and Oil flow from the Piston Pump ceases.
Orifices between the Control Valve and the Servo Piston control speed of the Camplate movement.
Neutral Adjustment Screw is to set Servo in Neutral position to prevent flow to motor, a Buzz Bar Head will
have a screw on both sides. Rotary head shown below.
FIGURE 40
PUMP
Servo Piston
Servo Piston Follower
Camplate
Neutral
Centering
Spring
Servo
Control
Solenoid
Spool
Servo
Pressure
Line
Servo Piston
Servo Control Supply Oil
Machete (Service Manual) 04/04
© 2004 Alamo Group Inc.
Camplate
Piston Asy.
Case Drain
Neutral Adjust Screw
Feed Back
Line
System Relief
and Check
Valve
Port "D"
To Motor
System Relief &
Check Valve
65
Control Lever
(removed
on later Model, replaced by
Block with Solenoid)
Port "C"
From Motor
Gerotor
Charge
Pump
Charge
Pump
Suction
Charge Pump
Relief Valve