Mould base for moulds for manufacturing thermoplastic containers and moulding device equipped with at least one mould equipped with such a base

A mould base for a mould for manufacturing, by blow moulding or stretch-blow moulding, containers made of thermoplastic material, the containers having a body and having a petaloid base with several feet distributed angularly and that extend approximately parallel to the axis of the container and are separated from each other by radiating valleys with convex bottoms, the mould base comprising:

• a moulding cavity for the moulding of the bases of the containers, comprising cavities that are angularly distributed, that extend approximately parallel to a vertical central axis of the mould base, and that are separated from each other by radiating ridges with a concave crest;
• the bottoms of the cavities are distributed along a substantially circular contour, each cavity, seen radially on either side of its deepest point, defined:
• towards the outside by a curved surface portion that, in radial cross-section, is substantially an arc of a circle, and
• towards the inside by a plane surface portion in which a plane portion adjacent to the curved surface portion has a slope between approximately 12° and 8° relative to a plane that is tangent to the curved surface portion and substantially perpendicular to the central axis of the moulding cavity;
• the plane surface portion is a broken-plane surface portion comprising at least two slopes, a first slope that is the slope of the plane portion adjacent to the curved surface portion and a second slope that is the slope of the plane portion located further toward the inside of the base of the moulding cavity, the second slope between approximately 17° and 23°;
• the plane surface portion intersects the curved surface portion at to form edges positioned substantially circumferentially and contained in the plane surface portion,
• the edges thus formed at the respective bottoms of the cavities results in the formation, for each foot of the container base, of projecting support ridges positioned substantially circumferentially.