What the hydraulics offer:-
To raise the roof on this bus needs a great deal of design expertise to ensure the roof remains level. A badly designed hydraulic system could easily twist and bend the roof, causing permanant damage.
Lowering a roof like this could look simple but actually the weight of this whole structure is only 100kg, so a single acting or gravity lowering approach would not be the best. To ensure good control when lowering, a double acting system is better utilizing precision flow dividing/combining devices ensuring each corner remains perfectly aligned.
Hydraulic roof system components
Hydraulic Power Pack
– In this case an AC hydraulic power unit is used as there is an on-board generator proving power for lights and refrigeration. The power level is not large as the roof only needs to move slowly and the weight is not great.
– Hydraulic directional control valves, solenoid operated.
– Precision flow divider with synchronisation feature ensures that any error in alignment is corrected every time the roof is operated.
Hydraulic ram
– Hydraulic cylinders in each corner give stability as well as power to raise the roof.
Electrical controls
– A simple up and down button control system allows even the least technical operator to serve the drinks on the top deck.