Preform with a concave bottom and an evolving thickness
OwnerChristophe Bunelinventor
Life of this patent
Estimating the term…
Abstract
Disclosed is a preform for a plastics container, which includes: a rotationally symmetrical body about a central axis; an open neck which extends in continuation of the body from an upper end of the latter; a bottom which closes the body starting from a lower end of the latter, the bottom being rotationally symmetrical about the central axis and having a central concavity and a protruding bulge around this concavity, the bottom having a thickness E, measured from an external face, that is variable in accordance with three different criteria respectively applied to three sections of the bottom, namely a central section [0; S1], an intermediate section [S1; S2] and a peripheral section [S2; L].
Claims18
Preform (1) of a container that is made of plastic material, which preform comprises:
- A rotationally-symmetrical body (3) around a central axis (X),
- An open neck (5) that extends in continuation of the body (3) starting from an upper end of the latter, and
- A bottom (7) that closes the body (3) starting from a lower end (8) of the latter, with the bottom (7) being rotationally symmetrical around the central axis (X) and having a central concavity (9) and a bulge (10) that protrudes around this concavity (9), with the bottom (7) having a variable thickness E, measured starting from an external face (17),
- wherein, in any cutting plane that passes through the central axis (X), the thickness E of the bottom (7) verifies the geometric rules (R1), (R4.1), (R4.2) and (R4.3) below, with the following being given:
- S the curvilinear abscissa measured on the external face (17), starting from the central axis (X) that acts as the origin;
- L the total curvilinear half-length of the bottom (7), measured on the external face (17) starting from the central axis (X) up to the lower end (8) of the body (3);
- S1 a value of the curvilinear abscissa S such that 0.2·L≤S1≤0.3·L;
- S2 a value of the curvilinear abscissa S such that 0.4·L≤S2≤0.6·L;
- E0 the thickness of the preform (1) at the lower end (8) of the body (3);
- d a diameter of one end (11) of the bottom (7), defined by the bulge (10);
- D an outer diameter of the body (3), measured at the junction with the bottom (7);
- [0;
- S1] a central cross-section of the bottom (7), defined by a curvilinear abscissa of between the origin and S1;
- [S1;
- S2] an intermediate cross-section of the bottom (7), defined by a curvilinear abscissa of between S1 and S2;
- [S2;
- L] a peripheral cross-section of the bottom (7), defined by a curvilinear abscissa of between S2 and L;
- (R1) the diameter d is such that:
- 0.2·D≤d≤0.5·D
- (R4.1) in the central cross-section [0;
- S1] of the bottom (7), the thickness E of the preform (1) is such that:
- 0.65·E0≤E≤0.95·E0
- (R4.2) in the intermediate cross-section [S1;
- S2] of the bottom (7), the thickness E of the preform (1) is strictly less than its value at any point of the central cross-section [0;
- S1];
- (R4.3) in the peripheral cross-section [S2;
- L] of the bottom, the thickness E of the preform (1) is increasing.
Dependencies are inferred from the claim text.