CARGO DECK CRANE

VOLUME 2

TECHNICAL INFORMATION

TYPE

CBW 20(30)/26 ST

ORDER --- NO.

160 052
162 053

Subject to alteration!
1st Edition: 11.02.2002 /ab

LIEBHERR ---WERK---NENZING GMBH, P.O.Box 10, A---6710 Nenzing / Austria / Europe

Phone (05525) 606---0, Telex 052141 lwn a, Telefax (05525) 606---200
 FOREWORD

This DOCUMENTATION has been prepared to allow the safe operation of the LIEB-
HERR crane while utilizing the crane’s full range of operating possibilities. In addition,
the manual emphasizes the daily routine maintenance and informs the operator of the
operating principles of important assemblies and systems.

VOLUME 1 --- INSTRUCTION / MAINTENANCE MANUAL

VOLUME 2 --- TECHNICAL INFORMATION

VOLUME 3 --- SPARE PARTS LIST

The DOCUMENTATION is prepared for extended service---, repair--- and maintenance

work as well as ordering spare parts. This manual shall be used by trained Service---per-
sonnel only.

This LIEBHERR crane shall be operated and serviced by from LIEBHERR---WERK NEN-
ZING trained or authorized personnel only.

The procedures described in the DOCUMENTATION and general safety precautions

shall be observed at all times.

NON---OBSERVANCE OF THESE RULES CAN RESULT

IN PERSONAL INJURY AND STRUCTURAL DAMAGE.
Special attention shall be given to the safety devices built---in to the crane. They shall
be tested at regular intervals for good condition and proper operation. Crane operation
is prohibited if the safety devices are not working properly.

”S A F E T Y A L W A Y S C O M E S F I R S T”
must be the way of thinking and behaviour before, during and after crane operation.

If you receive any further information for the crane, such as technical modifications or
changes concerning operation, maintenance, or spare parts --- please attach them to
provided volumes.
 ELECTRIC / ELECTRONIC

INDEX − VOLUME 2

4. TECHNICAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5

4.1. TECHNICAL DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5

4.2. TECHNICAL DESCRIPTION − ELECTRIC . . . . . . . . . . . . . . . . . . . . . . . . . 4.7

5. DESCRIPTION OF HYDRAULIC FUNCTIONS . . . . . . . . . . . . . . . . . . . . 5.3

5.1. GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3

5.2. DESCRIPTION OF THE MAIN HYDRAULIC COMPONENTS . . . . . . . . . 5.5
5.3. EXPLANATION OF HYDRAULIC CONTROL SYSTEM . . . . . . . . . . . . . . . 5.13

6. EMERGENCY OPERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3

6.1. INSTRUCTIONS FOR EMERGENCY HAND PUMP . . . . . . . . . . . . . . . . . 6.3

6.2. PROCEDURE TO LOWER THE LOAD" FOR HOISTING GEAR . . . . . . 6.5
6.3. PROCEDURE TO LOWER THE JIB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.7
6.4. PROCEDURE TO RELEASE THE SLEWING BRAKES . . . . . . . . . . . . . . . 6.9

7. DRAWINGS

8. ADDITIONAL DEVICES

8.1 MOTOR GRAB MZGL 12000−3−L

8.2 CABLE REEL

−4.1− 1028
ELECTRIC / ELECTRONIC

1028 −4.2−
 ELECTRIC / ELECTRONIC

INDEX

4. TECHNICAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5

4.1. TECHNICAL DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5

4.1.1. GENERAL DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5
4.1.2. WORKING SPEEDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5
4.1.3. SLEWING RANGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5

4.2. TECHNICAL DESCRIPTION − ELECTRIC . . . . . . . . . . . . . . . . . . . . . . . . . 4.7

4.2.1. POWER SUPPLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.7
4.2.2. INSTALLED POWER RATINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.7
4.2.3. SWITCH CABINET X1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.8
4.2.4. OPERATION OF MAIN BREAKER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.8
4.2.5. EMERGENCY STOP FUNCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.8
4.2.6. OPERATION OF MAIN MOTOR (HYDRAULIC DRIVE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.8
4.2.7. VENTILATION AND HEATING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.9
4.2.8. MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.9

−4.3− 1028
ELECTRIC / ELECTRONIC

1028 −4.4−
 ELECTRIC / ELECTRONIC

4. TECHNICAL DESCRIPTION

4.1. TECHNICAL DATA

4.1.1. GENERAL DATA

PERMISSIBLE CAPACITIES:
2−fall operation: 30 metric tonnes SWL from 4,2 m to 26 m working radius (hook operation)
20 metric tonnes SWL from 4,2 m to 26 m working radius (grab operation)

WORKING RANGE:
Maximum radius: 26 m (at 15° jib inclination)
Minimum radius: 4,2 m
Maximal lifting height: 43 m

PERMISSIBLE HEELING: 0°
PERMISSIBLE TRIM: 0°

WEIGHT OF CRANE: approx. 48,5 to

AMBIENT TEMPERATURE: −25°C to +45°C

DESIGN TEMPERATURE: − 10 °C
HYMIDITY: max. 93%

4.1.2. WORKING SPEEDS

− HOISTING (2−fall operation):

Infinitely variable with automatic power regulator:
0 − 25 m/min with 30 metric tonnes (hook operation)
0 − 33 m/min with 20 metric tonnes (grab operation)
0 − 50 m/min with empty hook

− LUFFING:
Infinitely variable speed:
Luffing from min. to max. working radius: 67 sec. with full load

− SLEWING:
Infinitely variable speed: 0 − 0,9 rev/min with full load and from max. to min. radius

4.1.3. SLEWING RANGE

360° unlimited and unrestricted.

NOTE:
The mentioned speed values are only theoretical values and may differ in case of different
effiency degrees. They are only valid at operation of one system at the time.

−4.5− 1028
ELECTRIC / ELECTRONIC

1028 −4.6−
 ELECTRIC / ELECTRONIC

4.2. TECHNICAL DESCRIPTION − ELECTRIC

4.2.1. POWER SUPPLY

MAIN SUPPLY: 3 x 380 V, 50 Hz, Smax appr. 270 kVA

AUXILLIARY SUPPLY: 3 x 220 V, 50 Hz, Pmax appr. 6 kW

4.2.2. INSTALLED POWER RATINGS

MAIN MOTOR
Voltage 3 x 380 V
Nominal power appr. 195 kW
OIL COOLER
Voltage 3 x 380 V
Nominal power appr. 3 kW
CABLE REEL
Voltage 3 x 380 V
Nominal power appr. 5,5 kW
GRAB
Voltage 3 x 380 V
Nominal power appr. 37 kW

SWITCH CABINET HEATING (X1)

Voltage 220 V
Nominal power 45 W
STANDSTILL HEATING MAIN MOTOR
Voltage 220 V
Nominal power 100 W
STANDSTILL HEATING SLIPRING COLLECTOR
Voltage 220 V
Nominal power 90 W
HEATING CABIN
Voltage 220 V
Nominal power 2000 W
HEATING OIL TANK
Voltage 220 V
Nominal power 700 W

FLOOD LIGHT JIB

Voltage 220 V
Nominal power 1 x 1000 W
CRANE LIGHTS
Voltage 220 V
Nominal power 3 x 60 W
CABIN LIGHT
Voltage 220 V
Nominal power 1 x 60 W

−4.7− 1028
ELECTRIC / ELECTRONIC
4.2.3. SWITCH CABINET X1
Houses all control elements for crane control, lighting and heating system.
Following components are mounted at the front door of the switch cabine:
−manual operated main switch X1−Q01
−main switch for lighting and heating X1−S02
−hour counter X1−P01 (counting the hours run by the hydr. pump, for service purpose)
−emergency stop switch X1−S01

4.2.4. OPERATION OF MAIN BREAKER

MAIN BREAKER
ON"

The main breaker must be switched on manually at the front door of the switch cabinet X1. The pilot light
crane on" (at the switch unit X20) illuminates
Preconditions:
−Power supply 3 x 380 V present from ship
−All emergency stop buttons released

MAIN BREAKER
OFF"

For disconnection of the power of the crane (maintenance purpose) turn off main breaker manually by press

ing the crane off" button (at the switch unit X20).

4.2.5. EMERGENCY STOP FUNCTION

If one of the emergency stop buttons is pressed the main contactors X1−K03, X1−K04 de−energize and
the main motor stops. All brakes close immediately, because of the pressure loss in the brake lines.
These buttons should be used:
−For shutting down the crane in an emergency case
Emergency push buttons are located:
−At the switch unit X20
−At the switch cabinet door X1
−At the ascent ladder

4.2.6. OPERATION OF MAIN MOTOR (HYDRAULIC DRIVE)

4.2.6.1. MAIN MOTOR START

− Unlock all "EMERGENCY STOP" buttons

− Switch on the main switch X1−Q01 manually on switch cabinet X1
− Check if pilot light "CRANE ON" is on
− All joy sticks have to be in neutral position
− Press push button "MOTOR ON"
− Check if inserted pilot light "MOTOR ON" comes on after a view seconds (run up time of main motor).
The main drive fails to start, if:
− the main switch is "OFF" (EMERGENCY STOP)
− the overcurrent relay for the main motor has tripped
− the PTC protection (overheat protection) of the main motor has tripped
− the hydraulic oil level is too low
The operating hours counter − on switch cabinet X1 − for the main electric motor records the number
of hours run by the hydraulic pump assembly. This data output is used to determine maintenance intervals.

1028 −4.8−
 ELECTRIC / ELECTRONIC
4.2.6.2. MAIN MOTOR OFF

MANUAL SHUT DOWN:

− make sure all motions of the crane are stopped (all joy sticks in neutral position)
− press push button "MOTOR OFF"
− the main motor stops. The control circuit is interrupted and the multi disc brakes are applied immediately
− if required press push button "CRANE OFF" to shut down the main breaker X1−Q01

AUTOMATIC SHUT DOWN:

In the following cases the main motor is automatically shut down and all brakes apply immediately:
− the overcurrent relays for the main motor has tripped
− the PTC protection (overheat protection) of the main motor has tripped
− the hydraulic oil level is too low

EMERGENCY SHUT DOWN:

− Press one of the "EMERGENCY STOP BUTTONS". See section "EMERGENCY STOP FUNCTION"

4.2.7. VENTILATION AND HEATING

The electr. operated ventilator for oil cooling also circulates the air in the slewing column.
SWITCH CABINET HEATING
Preheats the switch cabinet at low outside temperatures and thus to prevent condensation.
THE HEATING
Inside the slewing column keep the hydraulic oil warm. Temperature control is done by a 20°room thermo

stat.

4.2.8. MAINTENANCE

Following maintenance works must be carried out:

−The filters on the switch cabinet fan should be renewed or cleaned approximately every 3000 working
hours
−All terminal screws in the switch cabinets, terminal boxes and on the equipment itself, should be checked
once a year and tightened if loose.
−In addition, all safety and emergency stop switches should be checked regularly (see "MAINTENANCE
LIST")
−Check and if necessary clean slip ring collector from carbon particles
−Check condition of brush carbons and grease bearings of slip ring collector if grease nippels are provided.

WARNING
Before opening any electric equipment, it is essential to switch of the power
supplies from ship !

−4.9− 1028
ELECTRIC / ELECTRONIC

1028 −4.10−
 HYDRAULIC

INDEX

5. DESCRIPTION OF HYDRAULIC FUNCTIONS . . . . . . . . . . . . . . . . . . . . 5.3

5.1. GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3

5.2. DESCRIPTION OF THE MAIN HYDRAULIC COMPONENTS . . . . . . . . . 5.5

5.2.1. THE VARIABLE SWASH PLATE PUMP TYPE A11VO LRDS . . . . . . . . . . . . . . . . . . . . . . . 5.5
5.2.2. CONTROL BLOCK TYPE LUDV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.7
5.2.3. SLEWING SAFETY BLOCK VALVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.9
5.2.4. LOWERING BRAKE VALVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.10
5.2.5. HYDRAULIC OPERATED JOY STICK TYPE TH6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.11

5.3. EXPLANATION OF HYDRAULIC CONTROL SYSTEM . . . . . . . . . . . . . . . 5.13

5.3.1. GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.13
5.3.2. FUNCTION OF THE LUDV−CONTROL SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.13
5.3.3. FUNCTION OF HYDR. CONTROL SYSTEM (LUDV) WITH ONE USER . . . . . . . . . . . . . 5.13
5.3.4. FUNCTION OF HYDR. CONTROL SYSTEM (LUDV) WITH TWO USERS . . . . . . . . . . . . 5.13

−5.1− 1028
HYDRAULIC

1028 −5.2−
 HYDRAULIC

5. DESCRIPTION OF HYDRAULIC FUNCTIONS

5.1. GENERAL

NOTE:

ALL HYDRAULIC DRAWINGS NEEDED FOR THE HYDRAULIC SYSTEM ARE FOUND IN SECTION

DRAWINGS".

The numbers quoted in the description of electrical assemblies and hydraulic equipment are identical with
those, which appear in the hydraulic circuit diagram, electric diagram, illustrations and oil pressure table.
All items in brackets ( ) are explained under item 5.2 (Description of main hydr. components).
The variable axial piston pumps HA, EA and the the two gear pumps are flanged together and are driven
from an electric motor via a coupling.
The variable axial piston pumps HA, EA supply the oil for all the crane movements (hoisting, luffing and slew

ing).
Gear pump A1 supplies the control oil for all the joy sticks.
Gear pump A21 supplies the oil to the hydraulic oil cooler unit.

ARRANGEMENT OF HYDRAULIC PUMP ASSEMBLY:

1 Gear pump A1
4
2 Gear pump A21
3 Variable axial piston pump EA
4 Variable axial piston pump HA
5
5 Coupling
6 Elecrtric main motor 4A−M01

−5.3− 1028
HYDRAULIC

1028 −5.4−
 HYDRAULIC

5.2. DESCRIPTION OF THE MAIN HYDRAULIC COMPONENTS

5.2.1. THE VARIABLE SWASH PLATE PUMP TYPE A11VO LRDS (FOR OPEN HYDR. CIRCUITS)

HYDRAULIC SCHEMATIC

Connections:
B Service line port
6
S Suction port
5 4 1 3
T1 Air bleed, tank return line
T2 Air bleed, tank
G Control pressure port
X Port for difference pressure control (sense
2
port)
M Gauge point for pressure port

Layout of components:
1 Pilot control valve
2 Rocker arm
3 Main displacement piston
4 Pressure cut off valve
5 Load sensing valve
6 Counter piston

General description

The A11VO is a variable pump of a axial piston swashplate design for use in open circuit hydrostatic drives.
It is suitable for use in either mobile or industrial applications. The pump operates under self−priming condi

tion, with tank pressurisation or with charge pump (impeller). A wide variety of controls are available. Setting
of the constant power control is possible via external adjustments, even when the unit is operating. The
pump is available with a through drive to accept a gear pump or a second axial piston pump up to the same
size (100 % through drive). Output flow is proportional to drive speed and pump displacement and is ste

plessly variable between maximum and zero.

Constant power control (LRDS) The constant power controls the output volume
of the pump in relation to the operating pressure
so that, at a constant drive speed, the preset drive
power is not exceeded.

pB x Vg = constant

Setting range pB = Operating pressure

Operating pressure

Start of control Vg = Displacement

Optimum power usage is obtained by accurately
following the power hyperbola.
pB (bar)

Operating pressure applies a force on piston (3)

within the control piston on the rocker arm (2). An
externally adjustable spring force is applied to the
Vgmin Displacement Vgmax other side of the rocker to determine the power
setting.
Should the operating pressure exceed the set
spring force, the pilot control valve (1) is operated
via the rocker arm (2), allowing the pump to swiv

el towards zero output. This in turn reduces the
effective moment on the arm of the rocker, thus
allowing the operating pressure to rise in the
same ratio by which the output flow is reduced
(pB x Vg = constant).

−5.5− 1028
 HYDRAULIC

Pressure cut−off (LRDS)

Integral pressure cut−off (LRDS)
Integral pressure cut−off
Setting range The pressure cut−off is in effect a constant pres

sure cotrol which swivels the pump back to Vgmin
when the preset operating pressure is reached.
This function overrides the constant power con

trol, i. e. the constant power control is effective
below the the preset operating pressure. The
Operating pressure pB (bar)

pressure valve cut−off (4) is integrated into the

control housing and is set in the factory to a fixed
pressure.
Setting range from 50 to 320 bar (size 35).
Settting range from 50 to 370 bar (size 60 − 250).

Vgmin Displacement Vgmax

Load sensing (LRDS)

The load sensing valve (5) is a flow control valve
which operates as a function of the load pressure
to regulate the pump displacement in order to
match the requirement of the consumer unit. The
pump flow is influenced by the external orifice
(control block, throttle) fitted between pump and
serviced unit, but is not affected by load pressure
throughout the the range below the power curve.
The valve compares pressure before and after
the orifice and maintains the pressure drop (dif

ferential pressure) across the orifice − and there

fore the pump flow − constant.
Operating pressure pB (bar)

If differential pressure increases, the pump is

swivelled back towards Vgmin, and differential
pressure decreases the pump is swivelled out to

wards Vgmax, until a balance is restored within the
valve.
pdiff = ppump − pservice unit
Differential pressure may be set within the range
14 bar to 25 bar. The standard setting is 18 bar.
The standby pressure for zero stroke operation
(orifice closed) is approx. 2 bar above the differ

Vgmin Displacement Vgmax ential pressure setting. The constant power con

trol and the pressure cut−off are superimposed
on the load sensing valve, i. e. the load sensing
function operates below the set power hyperbola
and set pressure.
The orifice is not included in the standard supply.

1028 −5.6−
 HYDRAULIC
5.2.2. CONTROL BLOCK TYPE LUDV (FOR OPEN HYDR. CIRCUITS)

HYDRAULIC SCHEMATIC:

3 3 3 3

5 5 5

2 2 2 2

6 1 1 1 1

Connections: Layout of components:

P1, P2 Oil supply from pump 1 Pressure scale valve
T1, T2 Tank return line 2 Sense bore
A1, B1 Working lines to user 1 3 Pressure limiting valves
(max. working pressure)
A2, B2 Working lines to user 2 4 Pressure limiting valves
(max. system pressure)
A3, B3 Working lines to user 3 5 Main piston
A4, B4 Working lines to user 4 6 Pressure release valve

a1, b1 Control ports (joy stick) for user 1

a2, b2 Control ports (joy stick) for user 2
a3, b3 Control ports (joy stick) for user 3
a4, b4 Control ports (joy stick) for user 4
LS Load sensing connection

GENERAL DESCRIPTION:

This control block guarantees:

−Load indepedent movement of all users

−Splitting of oil quantity at simultaneous operation of different users in correspondence to the main piston
position
−Control of variable pump, meaning pump only delivers as much oil as used at the time (less heat consump

tion, higher effiency)

−5.7− 1028
 HYDRAULIC
LAYOUT OF LUDV CONTROL BLOCK

mech. limit adjustment

of main piston

pressure limiting valve (3)

screw for air bleed

control pressure connection

(e. g. a1 from joy stick)

sense bore (2)

pressure scale valve (1)

main piston (5)

control pressure connection

(e. g. b1 from joy stick)

screw for air bleed

pressure limiting valve (3)

mech. limit adjustment

of main piston

1028 −5.8−
 HYDRAULIC
5.2.3. SLEWING SAFETY BLOCK VALVE

HYDRAULIC SCHEMATIC

Connections:
A, B Oil supply
1 A1, B1, A2, B2 Outlet to the hydr. motors
1
T Feed pressure connection
XA, XB Gauge connections
WV Brake connection

2 2
Layout of components:
1 Interlock valves with non
return valves
2 Non return valves
3 Change over valve

GENERAL DESCRIPTION:
Interlock valves (1) release the flow back from the hydr. motor to the low pressure side only if the pressure
has built−up in the opposite pressure line.
Non return valves (2) allow the oil to flow into one direction only. The return oil from the hydr. motor must
pass through interlock valve as the non return valves block the oil.
Change over valve (3) connects the corresponding pressure A or B with the lamella brakes.

−5.9− 1028
HYDRAULIC
5.2.4. LOWERING BRAKE VALVE

HYDRAULIC SCHEMATIC:

4 Connections:

A, C Oil supply lines

B, D Outlet to hydr. motor
X Port for control of lowering brake
valve
1
MC/D Control port
BR Connection for disc brake
5 MA, MB Gauge connections

Layout of components:

1 Lowering brake valve

5 2 Changeover valve
2 3 Sinter filter
4 Non return valve
5 nozzles
3

GENERAL DESCRIPTION

Lowering brake valve (1) releases the oil flow from the hydr. motor back to the tank via the LUDV block.
It is controlled by the pressure from port X.
Via changeover valve (2) the multiple disc brake is released from oil supply line A or C.

The actual working pressure in the hoist line can be measured at gauge connection MA.

1028 −5.10−
 HYDRAULIC
5.2.5. HYDRAULIC OPERATED JOY STICK TYPE TH6

HYDRAULIC SCHEMATIC

Single control: Double control:

(with integrated electric contact)

5 5

5 5

Connections: Layout of components:

P Control pressure circuit 5 Proportional control valves

T Tank return line 6 Integrated el. contact
1, 3 Control lines for user 1 to control block
2, 4 Control lines for user 2 to control block

GENERAL DESCRIPTIONS
−Sensitive control by means of extremely low operating forces and thus an increase in ease of operation
−Positive reference points in the lever position, before start of movement and at the end of fine control
−All connections on buttom face of unit
−Safe return and reduction of response time by direct return of the plunger to neutral position
−Stainless steel and brass plunger components offer anti−corrosion and non−stick feature

MAINTENANCE:
−Maintenance free

−5.11− 1028
HYDRAULIC

Layout of joy stick:

DESCRIPTION OF FUNCTION:

Hydraulic pilot units type TH6 operate on the basis of direct operating pressure reducing valves.
They comprise mainly the operating element (1), the valve cartridge comprising regulating spool (2), regulat

ing spring (3), return spring (4), plunger (5) and the housing (6).
Pilot light units TH6 offer pressure−related fine adjustment of valves, pump and motor control.
In neutral position, the operating element is held in zero position by return spring (4). When lever (1) is oper

ated, the plunger (5) is pushed against the return spring (4) by means of the switch plate (7). At the same
time, the regulating spool (2) is pushed through the regulating spring (3). When the regulating stroke begins,
there is a connection from port P via bore (8) and ports 1, 2, 3 or 4 to the unit to be adjusted (valve, pump
or motor). These adjustments are related to the lever position and the regulating spring characteristic.
A special feature of the TH6 pilot unit is the increase in the fine control range when using Rexroth high pres

sure mobile control blocks and sandwich mobile control blocks. This range is indicated by definite reference
points.
In connection with the pilot oil supply system, the pressure remote can function without a separate pilot
pump. Hand emergency is guaranteed when the prime mover is not running, due to the oil supply in the
accumulator of this system.
Rubber gaiter (9) protects the mechanical components from contamination, so that the pilot units are suit

able for the most difficult applications conditions.

1028 −5.12−
 HYDRAULIC

5.3. EXPLANATION OF HYDRAULIC CONTROL SYSTEM

All items in brackets ( ) are shown under item 5.2 (Description of main hydraulic components).

5.3.1. GENERAL

The control block LUDV A50 guarantees:

−Load independent movement of all users
−Splitting of oil quantity at simultaneous operation of different users in correspondence to the main piston
position.
−Control of variable pump, meaning pump only delivers as much oil as used at the time (less heat consump

tion, higher effiency).

5.3.2. FUNCTION OF THE LUDV−CONTROL SYSTEM

5.3.2.1. FUNCTION OF SENSE BORE

The function of sense bore (2) can be compared with the function of an adjustable nozzle. The sense bore
(2) causes a difference pressure between the variable pump and the use (e. g. variable motor, hydraulic
cylinder).

5.3.2.2. FUNCTION OF PRESSURE SCALE VALVE

The function of pressure scale valve (1) can be compared with a hydraulic controlled pressure limiting valve
which is controlled by the pressure from the use creating the highest pressure.

5.3.3. FUNCTION OF HYDR. CONTROL SYSTEM (LUDV) WITH ONE USER

(E. G. MAIN HOIST
LIFTING")

At control of hydr. joy stick main hoist lifting" the control oil passes from control block H21 via port 3 and
a nozzle to port a1 at the LUDV− block A50. Through an internal bore the control oil passes to the control
port of main piston (5). The main piston moves, sense bore (2) opens and at the same time the main piston
(5) gives direction into lifting". The pressure from sense bore (2) acts on pressure scale valve (1) and sets
the internal piston in correspondence to the working pressure. The oil from variable pumps EA, HA can pass
via the opened main piston (5) and connection A2 to the hydraulic motor HU.
Via the pressure scale valve (1) the working pressure is sensed through port (LS) of the control block A50
at the load sensing valves (5) of the variable pumps EA, HA through part X.
One of the control of load sensing valve (5) the pump control oil increases and the output of variable pumps
EA, HA increases. The pressure scale valve (1) has only got two positions: opened or closed.
If the oil flow to the user changes due to the different control from the joy stick, the pressure difference be

tween pump and user (e. g. hydr. motor) changes at sense bore (2) of the control block more or less. That
means for a short time the oil flow to the sense bore (2) is the same but the opening of the main piston (5)
is smaller or bigger.
That causes a pressure change at the sense bore (2) which is sensed at the load sensing valve (6) of the
variable pumps EA, HA. The load sensing valve (5) corrects this pressure change by changing the pump
control oil and due to that the pitch of the variable pumps until a basic pressure difference of approx. 20 bar
has set up again (adjusted at load sensing valve (5) of the variable pumps EA, HA).

5.3.4. FUNCTION OF HYDR. CONTROL SYSTEM (LUDV) WITH TWO USERS

(E. G. MAIN HOIST AND SLEWING)

5.3.4.1. BOTH USERS ARE OPERATED WITH DIFFERENT WORKING PRESSURES AND FULL SPEED
(SATURATION MODE)

At operation of both users the highest pressure is setting up at pressure scale valves (1) via main pistons
(5). The pressure at the corresponding sense bores (2) will be always controlled to the the highest working
pressure. That means, the pressure before and behind all sense bores (2) are the same. The pressure
between the variable pumps and the users will be kept at a costant value by the load sensing valve (5) inside
the variable pumps EA, HA.

−5.13− 1028
HYDRAULIC
5.3.4.2. MORE USERS IN OPERATION

If the oil consumption of all users used at the time is higher than as the max. pump output, the pressure
difference between the highest working pressure and the pump pressure gets smaller and therefore all pres

sure differences at the sense bores (2). The working pressure remains at a constant value.
That means, the distribution of the oil flow to all users will be reduced at the same relation as well as the actual
speeds of all users.
Characteristics of oil flow:
At max. pump delivery (e. g. 100l/min) one user is operated needing 80 % of that delivery.
At operation of a second user needing another 50 % of the pump delivery the oil flow to both users will be
reduced at a ratia of 8:5 (61,5 l : 38,5 l).
Characteristics of pressure:
At max. pump delivery (e. g. 100 l/min) and operation of one user with 100 % the pressure difference between
the variable pump and the user will be approx. 20 bar (adjusted at load sensing valve (5) of variable pumps).
At operation of a second user with another 100 % the pressure difference wil drop from 20 bar to approx.
10 bar.
The oil flow to both users will be limited to approx. 50 l/min each.

CHARACTERISTICS OF OIL FLOW BETWEEN VARIABLE PUMP AND USERS

Q PUMP < ∑ Q CONSUMER

1028 −5.14−
 EMERGENCY OPERATIONS

INDEX

6. EMERGENCY OPERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3

6.1. INSTRUCTIONS FOR EMERGENCY HAND PUMP

(only at main motor standstill) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3
6.1.1. GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3
6.1.2. LAYOUT OF EMERGENCY HAND PUMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3

6.2. PROCEDURE TO LOWER THE LOAD" . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.4

6.2.1. LAYOUT DRAWING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.4

6.3. PROCEDURE TO LOWER THE JIB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.5

6.3.1. GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.5
6.3.2. PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.5
6.3.3. LAYOUT DRAWING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.5

6.4. PROCEDURE TO RELEASE THE SLEWING BRAKE . . . . . . . . . . . . . . . . 6.6

6.4.1. LAYOUT DRAWING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.6

−6.1− 1028
EMERGENCY OPERATIONS

1028 −6.2−
 EMERGENCY OPERATIONS

6. EMERGENCY OPERATIONS

6.1. INSTRUCTIONS FOR EMERGENCY HAND PUMP

(only possible at main motor standstill)

6.1.1. GENERAL

The hand pump shall be used only in case of a total standstill of the crane.
It is possible to carry out following emergency movements or operations:
− lower the load to ground (open brakes of hoisting winch and/or lower jib)
− turn the crane (open the slewing brakes)

WARNING !
The operation of the emergency hand pump must be done at a place
from where the emergency movement can be seen!

In case of emergency operation there is no stopping of crane move

ments by limit switches or other safety devices. Therefore the move
ments have to be supervised by additional personnel !

6.1.2. LAYOUT OF EMERGENCY HAND PUMP

5
3

1 Pump lever
2 Pressure gauge (minimum 15 bar to release the brakes)
3 Connection to hydraulic system (pressure line of pump)
4 Oil filling and dipstick
5 Breather filter
6 Tank

NOTE ! At longer usage of hand pump during emergency operation (for example at large lifting heights)
check oil level of hand pump with dipstick and if necessary refill tank with hydraulic oil.

−6.3− 1028
EMERGENCY OPERATIONS

1028 −6.4−
 EMERGENCY OPERATIONS

6.2. PROCEDURE TO LOWER THE LOAD" FOR HOIST GEAR

6.2.1. PROCEDURE

−Close hand valve H63 to disconnect hoist gear from LUDV block
−Close hand valve H62A ("emergency position") and connect the hand pump to the hoisting brake H61U.
−Change over position of hand valve H62 to connect the A’ and B’ line of the hoisting motor HU to the hand
pump
−Increase the pressure to the disc brake by use of the hand pump.
−Now the multi disc brake H61U opens and the load will lower as long as the hand pump is operated.

ATTENTION !
After emergency operation is finished:
Change back hand valves H63, H62, H62A to original position.

6.2.2. LAYOUT DRAWING

three−way
valve H62A

hand valve H63

three−way valve H62

−6.5− 1028
EMERGENCY OPERATIONS

1028 −6.6−
 EMERGENCY OPERATIONS

6.3. PROCEDURE TO LOWER THE JIB

At a total black out on the crane or any failure on the hydraulic system the jib can be lowered by use of the
built−in adjustable throttle valve.

6.3.1. PROCEDURE

−Open hand valve E69

−Open slowly adjustable throttle valve E60 (located at the top of the hydr. tank) and the jib starts to lower
−With adjustable throttle valve E60 it is possible to adjust the lowering speed of the jib.

ATTENTION
After the emergency operation is finished, throttle valve E60 must be closed
completely and hand valve E69 brought back to operational position .

6.3.2. LAYOUT DRAWING

hand valve E69

adjustable throttle valve E60

−6.7− 1028
EMERGENCY OPERATIONS

1028 −6.8−
 EMERGENCY OPERATIONS

6.4. PROCEDURE TO RELEASE THE SLEWING BRAKES

6.4.1. PROCEDURE

−Close hand valve D62A and connect the hand pump

−Open bypass valve D63 (pressure balance in the main lines)
−Increase the pressure to the disc brakes by use of the hand pump
−Turn the crane slowly by additional gear (e. g. second crane, chain block)

ATTENTION !
After the emergency operation is finished, hand valve D62A and bypass
valve D63 must be brought back to original position !

6.4.2. LAYOUT DRAWING

Hand valve D63

Three way
valve D62A

−6.9− 1028
EMERGENCY OPERATIONS

1028 −6.10−
 DRAWINGS

7. DRAWINGS

General drawings:
DRAWING TITLE: DRAWING NUMBER: PAGE: MODIFY:
General arrangement CBW 20(30)/26 ST 5016 001 00 00 000−000 1 of 1
Reeving plan 2787 721 00 00 000−000 1 of 1

Hydraulic drawings:
DRAWING TITLE: DRAWING NUMBER: PAGE: MODIFY:
Hydraulic schematic 5016 970 00 00 001−000 1 to 5

Electric drawings:
DRAWING TITLE: DRAWING NUMBER: PAGE: MODIFY:

Outline power supply 5016 600 00 00 031−000 1 to 5

Outline electric of crane 2744 600 00 00 032−009 1 to 8
Electric wiring diagram 2744 600 00 00 061−009 1 to 36

Add. equipment grab + cable reel control 2787 690 00 00 000−003 1 to 13

Add. equipment load limit grab operation 5020 690 00 00 000−000 1 to 7
Add. equipment pressure limitation hoisting gear 2753 690 00 02 000−003 1 to 6

1028
 ADDITIONAL DEVICES

8 ADDITIONAL DEVICES

8.1 MOTOR GRAB MZGL 12000−3−L

8.2 CABLE REEL

1028
 ADDITIONAL DEVICES

8.1 MOTOR GRAB MZGL 12000−3−L

1028
 ADDITIONAL DEVICES

8.2 CABLE REEL

1028