USE - This control system is used to operate four or
six double acting cylinders. The valve panel permits operation of all cylinders
simultaneously. It can also be used to operate one or more cylinders
individually.
TYPICAL APPLICATIONS
- Operating a set of hydraulic jacking cylinders to push
steel or concrete pipe under roadways
- Operating jacking cylinders to propel a tunnel shield.
OPERATION -See Type III Control for operation of the
relief valve, venting valve, and jog button. The manually operated rotary 4-way
valves have three positions:
- Position 1.: In this position pressure will be applied to
Port A below causing the ram to extend when the jog button is pushed.
- Position 2.: In this position (Neutral) all ports are
blocked locking the cylinder.
- Position 3.: In this position pressure will be applied to
Port B below which is common to all cylinders.
The operator selects the cylinder or cylinders he wants to
move by moving the valve handles for these cylinders into the correct position.
He then operates the jog button until the desired ram travel has occurred. The
valve panels are mounted on the pump units. However, they can be shipped
separately and remotely mounted if desired.
If these units are to be used to raise a load, a "failsafe" globe and check
valve must be added. See Type IV Control
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