Patent ID: 8011919

Claim:
Mould base for a mould for manufacturing, by blow moulding or stretch-blow moulding, containers made of thermoplastic material, said containers having a body and having a base of the type known as petaloid with several feet which are equidistantly distributed angularly, which extend approximately parallel to the axis of the container and which are separated from each other by radiating valleys with convex bottoms, said mould base having a moulding cavity comprising, for the moulding of said bases of the containers, several cavities which are equidistantly distributed, which extend approximately parallel to the axis of the mould base and which are separated from each other by radiating ridges with a concave crest, the bottoms of said cavities being distributed along a substantially circular contour, each cavity, seen radially on either side of its deepest point, being defined: towards the outside by a curved surface portion which, 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 12° and 8° relative to a plane which is tangent to said curved surface portion and is substantially perpendicular to the axis of the moulding cavity, wherein the surface portion is a broken-plane surface portion with at least two slopes; a first slope, the slope of the plane portion adjacent to the curved surface portion; a second slope, the slope of the plane portion situated towards the inside of the base of the moulding cavity and that is between approximately 17° and 23°, and intersects said curved surface portion at a straight edge extending substantially circumferentially and contained in said plane, whereby the straight edge thus formed at the bottoms of the cavities leads to the formation, for each foot of the container base, of a projecting support ridge extending substantially circumferentially.