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COMPONENTS CX130
CASE TRAINING CENTER
AUGUST 2000
Auxiliary foot control
In neutral the auxiliary foot control is a closed center hydraulic valve. The inlet oil from the pilot pump is blocked at
both regulator spools (12). The ports (1), (2), are ported inside of the valve back to tank through a hole drilled in
the end, and a cross drilled hole in the regulator spool (12).
There are two springs (16) and (15) for each regulator spool (12). The larger diameter spring (16) provides the
return of the foot pedal and this spring (15) is the resistance the operator feels in his foot.
Typically the return springs are stronger in foot control than in hand control.
If the dust cover (23) under the foot control is torn, replace it. This will help prevent contamination from wearing
the U-seals (6) on the push rods (8).
The gap between the push rod (8) and the screw (21) can be adjusted. A too tight adjustment can cause partial
actuation of the spool. The contact area between the push rod (8) and the screw (21) should be lightly lubricated
with grease.
How it work
As the foot control is moved, the push rod (8) will push on both large and small diameter springs 16 & 15). The
smaller spring (15) will push the spool (12) and block of the return passage through the top metering notches.
The bottom metering land will open a passage and allow pilot oil out to the work spool of the travel control spool.
As the travel spool moves and compresses the spring in the control valve, the pressure will increase and push up
on the bottom of the regulator spool (12. When the pressure of the oil pushing on the travel spool equals the force
of the spring (15) behind the regulator spool (12) the bottom metering land will block the pilot supply. When the
force of the spring (15) equals the force of the pressure on the spool (12), the spool (12) is in a balanced position
to maintain a proportional pressure with the compression of the spring (15).
The foot control must be moved further to compress the small spring (15) and push the regulator spool (12)
further to increase the pressure again.
The foot control is nothing more than an adjustable pressure regulator, and the operator provides adjustment .
1 Body
2.Mounting braket
3.Seal bushing
4.Seal kit
5.U-seal
6.Wipper seal
7.O-ring
8.Push rod
9.Washer
10.Spring guide
11.Spring guide
12.Snap ring
13.Spring cup
14.Spring retainer
15.Regulator spring
16.Feel back spring
17.Bushing
18.Pin
19.Cam
20.Screw
21.Ajustment bolt
22.Nut
23.Rubber boot
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