DOCK LEVELLER POWER-PACK CIRCUIT - ABAG-Technik GmbH

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ABAG-Technik GmbH
Herrenstein 35
D-48317 Drensteinfurt
HRB-1044
AG Hamm
www.Roquet.de
Verkauf@Roquet.de
201003
Produktkatalog (GB/ES)
Dock-Leveller
DIN EN ISO 9001

Leveller in rest position - truck arrives
Leveller in rest position - doors open Leveller rising (lip still down)
Leveller raised - lip extends automatically Leveller raised- lip extended

Close-up of extended lift cylinder
with power pack behind
Close-up of extended lip cylinder
Leveller lowering with lip extended Leveller floating on truck - ready
for un-loading by fork-lift truck

Leveller rising (lip falls automatically) Leveller fully lowered
Leveller fully lowered in rest position - lip in "keepers"

Standard power pack - Roquet Nº 9034030
Main deck lift cylinder - Roquet Nº 9988
Lip cylinder - Roquet Nº 9349

Pedro Roquet, S.A.
A brief introduction to
standard Pedro Roquet
components for hydraulic
dock levellers.
May 2004

Pedro Roquet, S.A.
Roquet power packs for
folding-lip dock levellers
Standard power pack - Roquet Nº 9034030
(metal tank)
Standard power pack - Roquet Nº 2432030
(suitable for single and double lift cylinders)

Pedro Roquet, S.A.
Roquet cylinders for
folding-lip dock levellers
Folding-lip cylinder - Roquet Nº 9349
Single lift cylinder - Roquet Nº 2132
Double lift cylinder - Roquet Nº 2281

Pedro Roquet, S.A.
Roquet components for
extending-lip levellers
Extending / telescopic lip power pack - Roquet Nº 9928020
Extending / telescopic lip cylinder - Roquet Nº 9518
(this version 500mm stroke - also available 1000mm)
Lift cylinders are standard, as previous page

DOCK LEVELLER CIRCUIT FUNCTION
Explanation of function (numbers refer to circuit on page 2):
A. Motor turned on
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Pump flow passes through check valve 1 to port A (main deck cylinder).
Pressure rises to that required to lift the deck (let’s assume 80 bar). Pressure maintains pilotoperated
check valve 3 closed. At this stage there is no pressure on the pilot (upper side) of
pilot operated check valve 2 so the lip cylinder is connected directly to tank via the sequence
valve 5 and the p/o check valve 2.
At end of deck cylinder stroke the pressure increases until it reaches the pressure setting of
the lip sequence valve 5 (set 115 bar). This valve then swiches and the lip cylinder raises the
lip. When the lip is completely raised the pressure then increases until it reaches the
pressure setting of the main relief valve 4 (set 140 bar).
B. Motor now turned off
Pressure on the pump-side of check valve 1 falls to zero, allowing p/o check valve 3 to open
which allows fluid to pass from the main deck cylinder to the adjustable lowering valve 7 and
to tank via the energised safety valve 6. The pressure drop created by the returning flow
through the lowering valve 7 also holds shut the p/o check valve 2 so the lip cylinder remains
“up”.
The deck lowers until the lip (still “up”) contacts the truck, which then supports the leveller. At
this stage the p/o check valves 2 and 3 are both open so both cylinders are “floating”.
C. Motor turned on again
Repeat “Motor turned on” section above. Provided motor then turned off again before
reaching end of stroke of main deck cylinder then the lip will not raise and the leveller will
lower into it’s parked position.

DOCK LEVELLER POWER-PACK CIRCUIT
PEDRO ROQUET, S.A.
Antonio Figueras, 91
TONA 08551
(Barcelona) SPAIN
Tel.: +34 93 812 4664
Fax: +34 93 887 1798
Web: http://www.pedro-roquet.com
e-mail: roquet@pedro-roquet.com
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