Case CX130, Manual, Page: 36 / 262

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COMPONENTS CX130
CASE TRAINING CENTER
AUGUST 2000
Hand remote controls
In neutral the hand control is a closed center hydraulic valve. The inlet oil from the pilot pump is blocked at all four
regulator spools (27 ). The ports (1), (2), (3), (4) are ported inside of the valve back to tank through the notches in
the regulator spool (27).
There are two springs (20) and (21) for each regulator spool (27). The larger diameter spring (20) provides the
return of the handle and this spring (20) is the resistance the operator feels in his wrist.
As the operator views the control, the front and back spring are stronger than the left and right springs. The hand
control will require more effort to push and pull than to move side to side. The smaller springs (22) are the
regulator spring which connect the plunger (9) to the spool (27).
If the dust cover (26) under the hand control is torn, replace it. This will help prevent contamination from wearing
the seals (13) on the push rods (11) & (12).
The cam (24) that pushes on the push rods (11) or (12) can be rotated to adjust the free play in the hand control.
A too tight adjustment can cause partial actuation of the spool. The contact area between the cam (24) and the
push rods (11 & 12) should be lightly lubrecated with grease.
How it work
As the hand control is moved, the push rod (11 or 12) will push on both large and small diameter springs (20
&22).The smaller spring (22) will push the spool (27) and block of the return passage through the top meetering
notches.
The bottom meetering notches will open a passage and allow pilot oil out to the work spool of the equipement
control valve. As the work spool moves and compresses the spring in the control valve, the pressure will increase
and push up on the bottom of the regulator spool (27). When the pressure of the oil pushing on the work spool
equals the force of the spring (22) behind the regulator spool (27) the bottom meetering notches will block the
pilot supply. When the force of the spring (22) equals the force of the pressure on the spool (27), the spool (27) is
in a balanced position to maintain a proportional pressure with the compression of the spring (22).
The hand control must be moved further to compress the small spring (22) and push the regulator spool (27)
further to increase the pressure again.
The hand control is nothing more than an adjustable pressure regulator , and the operator provides adjustment .
1Body
2. Bottom plate
3. Washer
4. O-ring
5. Screw
6. Dowel
7. Spacer
8. Retainer
9. Spring guide
10.Push rod guide
11.Push rod
12.Push rod
13.Oil seal
14.O-ring
15.Spring cupt
16.Spring cup
17.Shims 18.Spring
19.Spring
20.Spring
21.Spring
22.Spring
23.U-joint
24.Cam
25.Nut
26.Rubber boot
27.Regulator spool