![background image](http://html1.mh-extra.com/html/jcb/js-200-series/js-200-series_service-manual_3627661275.webp)
31 - 7
Section E
Hydraulics
9803/6400
Section E
31 - 7
Issue 2*
Control Valve JS200/JS240
Operation
(continued)
Load Holding Valve
1. Boom Section (refer to fig. 5, 6, 14)
.
When the boom is lowered (Fig 6), the spool moves to the right as shown. At the same time, when
P
LC
is pressurised, the load
holding valve piston
D
pushes the poppet
B,
connecting Dr port. The oil in the load holding valve poppet (P) spring cavity
C
is
released to the Dr port and poppet (P) opens.
2. Dipper Section (refer to fig. 9, 10, 15)
.
During dipper crowd, the spool moves to the left as shown and the passage
W
from the load holding valve is connected to the
tank passage. The oil in the load holding valve poppet spring cavity
A
side creates differential pressure between the ram port
B
and is released, opening the poppet. (Fig 10)
During dipper dumping, the spool moves to the left as shown (Fig. 9) and when oil flows to passage
V
(Fig. 15-2) it resists the
force of the spring
D
of the load holding valve poppet (U), pushes open the poppet and flows to
A
L4
port.
When the spool is in neutral, the pressure from the cylinder port
B
is fed through hole
C
, goes around the poppet spring cavity
side
A
and, by the spring
D
force, seats the poppet.
Regenerative Circuit (Refer to Fig. 10, 16)
For this valve, a regenerative circuit is built into the dipper I spool.
During dipper crowd, (Fig. 10, 16), with the ram extending, the bottom side oil is insufficient and the pressure of passage
U
becomes lower than that of passage
V.
The pressure of passage
V
overcomes the spring
C
force and part of the oil which flows
from the cylinder port
D
through the spool neck to the tank pushes open the poppet (Y) and by flowing through the constriction
(Z), raises the pressure of passage
U
and prevents cavitation.
*
*
*
*
Summary of Contents for JS 200 Series
Page 57: ...9 1 Section 3 Routine Maintenance 9803 6400 Section 3 9 1 Issue 2 Component Location Diagram...
Page 113: ......
Page 137: ...5 3 Section C Electrics 9803 6400 Section C 5 3 Issue 2 Pump Control FLOW CHART...
Page 201: ...10 7 Section C Electrics 9803 6400 Section C 10 7 Issue 1 CAPs II Diagnostic system K C...
Page 215: ...Section E Section E Hydraulics 9803 6400 Issue 2 3 2 3 2 Schematics...
Page 217: ...Section E Section E 9803 6400 Issue 2 3 3 3 3 Hydraulics Schematics...
Page 218: ...3 5 Section E Hydraulics 9803 6400 Section E 3 5 Issue 1 Schematics Shuttle Block JS200 JS240...
Page 232: ...10 1 Section E Hydraulics 9803 6400 Section E 10 1 Issue 1 Hydraulic Pump JS200 JS240...
Page 233: ...10 2 Section E Hydraulics 9803 6400 Section E 10 2 Issue 1 Hydraulic Pump JS200 JS240...
Page 234: ...10 3 Section E Hydraulics 9803 6400 Section E 10 3 Issue 1 Hydraulic Pump JS200 JS240...
Page 263: ...30 2 Section E Hydraulics 9803 6400 Section E 30 2 Issue 1 Control Valve JS200 JS240...
Page 264: ...30 3 Section E Hydraulics 9803 6400 Section E 30 3 Issue 1 Control Valve JS200 JS240...
Page 265: ...30 4 Section E Hydraulics 9803 6400 Section E 30 4 Issue 1 Control Valve JS200 JS240...
Page 266: ...30 5 Section E Hydraulics 9803 6400 Section E 30 5 Issue 1 Control Valve JS200 JS240...
Page 267: ...30 6 Section E Hydraulics 9803 6400 Section E 30 6 Issue 1 Control Valve JS200 JS240...
Page 268: ...30 7 Section E Hydraulics 9803 6400 Section E 30 7 Issue 1 Control Valve JS200 JS240...
Page 327: ...51 12 Section E Hydraulics 9803 6400 Section E 51 12 Issue 1 Solenoid Valve 8 spool...
Page 328: ...55 1 Schematic Section E Hydraulics 9803 6400 Section E 55 1 Issue 1 Shuttle Valve...
Page 330: ...55 3 Schematic Section E Hydraulics 9803 6400 Section E 55 3 Issue 1 Cushion Valves...
Page 481: ...7 15 Section F Transmission 9803 6400 Section F 7 15 Issue 2 Motor...
Page 482: ...7 16 Section F Transmission 9803 6400 Section F 7 16 Issue 1 Motor...