Blow molding device, blow molding method, and preform sealing/positioning part

A blow molding device for blow-molding a preform which includes a mouth portion, a body portion, and a flange provided between the mouth portion and the body portion into a container, the blow molding device comprising:

• a pair of blow cavity split molds;
• a chuck member that chucks the mouth portion and conveys the preform to the pair of blow cavity split molds which are opened;
• a blow core mold that includes a tubular portion which surrounds circumferences of the mouth portion and the flange of the preform and introduces blow air into the preform, after the chuck member is retracted from the preform which is disposed in the pair of blow cavity split molds which are closed;
• and
• a pair of projecting members which have a halved ring shape and are provided detachably on each upper surface of the pair of blow cavity split molds,
• wherein each of the pair of projecting members includes:
• an airtight sealing portion which is in contact with a lower end face of the tubular portion of the blow core mold,
• a positioning portion which positions the flange of the preform when the pair of blow cavity split molds are closed,
• wherein the lower end face of the tubular portion of the blow core mold which is in contact with the airtight sealing portion is a bottom surface which is the lowest part of the blow core mold,
• wherein an outer circumferential surface of each of the pair of projecting members is not in contact with the blow core mold,
• wherein each of the pair of projecting members have an attaching portion which is provided further radially outwards than the airtight sealing portion and which is fastened to each upper surface of the pair of blow cavity split molds, and
• wherein the airtight sealing portion is formed on an upper surface of the projecting member, and the positioning portion for positioning the flange is formed on an inner circumferential surface of the projecting member.