of hydraulic piston cylinder devices a a 39 b b 39 and c c 39 are generally provided for the opening and closing of the roof the piston cylinder devices of each pair operate in parallel and are each provided on a side of the vehicle the piston cylinder device a is used for locking the cover 4 the pair a a 39 is used for the opening and closure of the cover 4 the pair b b 39 for moving the bow 5 and the pair c c 39 for folding and stretching of the proper roof 1 furthermore fig1 shows a hydraulic power unit indicated at 6 whereas 7 indicates the control valves for the various piston cylinder devices said valves being placed to form a compact unit from the power source 6 shown in fig1 the diagram of fig2 shows the electric motor driven pump 8 and the reservoir 9 for hydraulic fluid 10 indicates the pressure conduit of the pump the 34 spaces under the piston 34 of all of the four cylinders a a b and c are each separately connected to the pressure conduit 10 through an electric control valve 11a 11a 11b and 11c respectively the 34 spaces above the piston 34 of the piston cylinder devices a a b and c are connected to one another and are connected to the pressure conduit through a common solenoid valve 12 as may be seen in the diagram of fig2 all of the said electrically operated valves are.