2-55
Operating principle
When one of the RCV lever (1) is set to the operation position, the each spool is shifted to left
or right and the pilot oil flow is blocked. Then the pilot oil go to SH of the time delay valve (3).
This pressure moves spool (5) to the leftward against the force of the spring(8), so pilot pump
charged oil (P3) goes to the chamber G through port PG.
This pressure is applied to move the piston (6) to the upward against the force of the spring (9).
Thus, it releases the brake force.
Θ
a.
9
6
G
PG
11
D
8
5
3
10 7
P4=P3
SH
1
12
P3
2
4
2
1 Swing control lever
2 Main control valve
3 Time delay valve
4 Pilot pump
5 Spool
6 Piston
7 Poppet
8 Spring
9 Spring
10 Orifice
11 Spring
36072SM12