Figure 7.

HYDRAULIC

Figure 7.

The spools are hard plated for corrosion resistance and

contain notches to obtain metering control of the load.

Figure 8.

Check valves prevent back flow from cylinder ports to

inlet port.

Line up holes and install bolts and nuts. Tighten nuts

evenly to compress spring sufficiently to allow removal

An adjustable relief valve is incorporated in the valve to

of snap ring. Caution should be exercised as spring is

prevent excessive oil pressure in the hydraulic system.

compressed.

Unscrew nuts slowly until all spring

pressure has been released.

Make certain that reusable spools and check valve

poppets are clearly tagged so that when used in

A sleeve type tool (Fig. 9) can be made for ease in

reassembly, they can be matched to their respective

snap ring installation on spring centered type spools.

bores. Switching of the poppets may cause improper

Select a piece of round

seating and sticking. Switching spools may reduce side

clearance causing spools to bind or it may increase side

clearance causing excessive leakage.

No special tools are required for disassembling or

assembling the control valve, although tools described

below will be helpful.

For compressing the spring on spring centered spools,

two retainer plates with bolts and nuts (Fig. 8) may be

used. To compress spring, place one retainer plate over

eye end of spool and against bottom spring spacer and

the other retainer plate against the top spring spacer.

Figure 9.

B-149