4 – 62 Repair Manual RRE140/160/180/200/250 © BT
Functions and parameters
Hydraulic system 6000
T-code Valid from serial number Date Publication No.
815, 816 6051502 2008-08-21 261828-040
4.10.7 Lift and lowering function
Lifting and lowering of free lift
The free lift is controlled by a proportional valve, Q3/Q5, of replaceable
cartridge design.
On free lift lifting, the pump is started and the proportional valve Q3 is
fully opened. The lifting speed is regulated by the pump speed.
Free lift is lowered using the proportional valve Q5.
Transition from free lift to main lift
The valve block has separate connections and proportional valves for
main lift (Q2) and free lift (Q3). This allows a smooth transition from free
lift to main lift, by reducing valve opening for Q3 at the same time as
increasing valve opening for Q2.
In a similar fashion, the proportional valves Q4 and Q5 give smooth
transition on lowering, by reducing valve opening for Q4 at the same
time as increasing valve opening for Q5.
Lifting and lowering of main lift
Main lift is controlled by a proportional valve, Q2/Q4, of replaceable car-
tridge design.
On main lift lifting, the pump is started and the proportional valve Q2 is
fully opened. The lifting speed is regulated by the pump speed.
Main lift is lowered using the proportional valve Q4.
Reach movement, in and out
The valve for control of the reach movement, Q6/Q7, is a proportional
slide valve, non-replaceable.
For reach movement in the IN direction, the pump is started and valve
Q6 is activated. For reach movement in the OUT direction, the pump is
started and valve Q7 is activated. The speed of the reach movement is
regulated by the pump speed, with valves Q6 and Q7 providing soft
start and stop for the function.
The pressure limiter DV2 opens if the pressure exceeds 15 MPa (150
bar) on reach movement in the OUT direction. On reach movement in
the IN direction, the pressure is limited by DV1 to 25 MPa (250 bar).
To Next Page
Loading...
