Machine for making containers by blow-moulding plastic parisons

Machine for the manufacture of containers (13) by blow-molding preliminarily-injected preforms (1), comprising:

• a device (3) for conveying and holding in position preforms along a path on which a heat-treatment station (32) is positioned, with means (31) designed to keep two successive preforms spaced apart by a first pitch (P1);
• at least two molds (41, 42, 43, 44) arranged on the periphery of a blow-molding circular conveyor (4), in which the molds are wallet molds, each comprising at least two mold cavities (48A, 48B;
• 49A, 49B) and in which the longitudinal axes of two adjacent cavities are spaced apart by a second pitch (P2);
• means (5A) for modifying the pitch of the preforms, in order to convert them from the first pitch (P1) to the second pitch (P2);
• first means (5B) for transferring at least two preforms so as to collect them on the pitch-modification means when the preforms are spaced apart by the second pitch and to feed them into a mold;
• wherein the pitch-modification means (5A) comprises at least two adjacent movable devices (52), each fitted with a preform position-retention element (53) and arranged so as to be able to convert the position-retention elements to the first pitch (P1) when the position-retention elements are positioned opposite the device for conveying and holding the preforms, and to the second pitch (P2) when the position-retention elements are positioned facing the first transfer means.