Two or more rams or pistons

Full Title

Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor (extrusion blow-moulding B29C49/04) > Component parts, details or accessories; Auxiliary operations > Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die > using pistons, accumulators or press rams > Two or more rams or pistons