Adj 4.14 Counterbalance Valve - Challenge CMT-130TC Service Manual

ADJ 4.14 Counterbalance Valve

The knife hydraulic cylinder has a counterbal-
ance valve attached to the bottom port (Figure
4-29). The counterbalance valve provides
smooth operation of the knife assembly as it
moves down. If improperly adjusted, the knife
assembly will vibrate as it moves down.
Initial Actions
Check that the system pressure is set to 1,800-
2,000 PSI before making these adjustments.
Use ADJ 4.13 Hydraulic System Pressure to
check system pressure.
Procedure
1. Open the rear door and loosen the lock nut
on the counterbalance valve.
2. Close all doors then switch the main power
ON and main air ON.
3. At the touch screen on the front console,
press the "Setup" button to bring up the
setup options screen. The "Parameters" tab
should be active. Now press the "Enable
Cut Cycle" button near the lower right corner
of the screen.
4. Remove the lower left door panel and locate
the pressure gauge on the hydraulic power
unit. Have an assistant press the green start
button to initiate a cut cycle. Monitor the
pressure gauge as the knife moves down.
As the knife is moving down (without a book
in the machine), the pressure gauge should
read approximately 900 PSI.
5. To adjust the counterbalance valve, loosen
the lock nut then turn the adjustment screw
counter-clockwise to increase pressure or
clockwise to decrease pressure. Adjust the
screw until the valve operates consistently at
900 PSI.
CMT-130TC Book Trimmer
6. Tighten the lock nut on the valve. Close
rear door.
Figure 4-29. Counterbalance Valve
MAY 2019
4-19 4. Repair/Adjustment Procedures