Device for blowmolding of plastic

A device for blow forming thermoplastic material containing a heating device for the tempering of preforms and a blow device for receiving said tempered preforms from said heating device and for blow molding the preforms into a container, said blow device including a rotating wheel carrying at least one blow molding station, a carrier disk rotatably supported in said blow device and a preloadable control disk for controlling said blow station, wherein said carrier disk and said control disk cooperating to supply fluid under pressure to said blow molding station, said control disk including a surface having a plurality of grooves to which pressurized fluid is supplied, said carrier disk including a surface having a plurality of grooves, preloading means for urging said carrier disk surface into sealing engagement with said control disk surface with respective ones of said carrier disk grooves being in sealed fluid communication with selected ones of said control disk grooves whereby fluid at different pressures may be supplied to said blow molding station, said preloading means comprising at least one pneumatic spring supported on said device and operative to urge said carrier disk surface into sealing relationship with said control disk surface, and said pneumatic spring is connected to a pressure relief device allowing pressure free maintenance.