Container provided with a curved invertible diaphragm

1. Container ( 1 ) made of a plastic material, provided with a base ( 7 ) including a standing ring ( 8 ) forming a support flange ( 9 ) and a diaphragm ( 11 ) extending from the standing ring ( 8 ) to a central portion ( 10 ), said diaphragm ( 11 ) being capable of standing in an outwardly-inclined position,

wherein the diaphragm ( 11 ) connects to the standing ring ( 8 ) at an outer junction ( 12 ) forming an outer articulation of the diaphragm ( 11 ) with respect to the standing ring ( 8 );

wherein the diaphragm ( 11 ) connects to the central portion ( 10 ) at an inner junction ( 13 ) forming an inner articulation of the diaphragm ( 11 ) with respect to the central portion ( 10 );

whereby said diaphragm ( 11 ) is invertible with respect to the standing ring ( 8 ) from the outwardly-inclined position, in which the inner junction ( 13 ) extends below the outer junction ( 12 ), to an inwardly-inclined position in which the inner junction ( 13 ) extends above the outer junction ( 12 );

wherein, in the inwardly-inclined position, at least an inner portion ( 16 ) of the diaphragm ( 11 ) adjacent to the inner junction ( 13 ) is curved in radial section, with a concavity turned outwards with respect to the container ( 1 ); and

wherein, in the outwardly-inclined position, the diaphragm ( 11 ) has an inner portion ( 19 ) curved with a concavity turned outwards with respect to the container ( 1 ) and having a radius (R 3 ) of curvature, and an outer portion ( 20 ) curved with a concavity turned outwards with respect to the container ( 1 ) and having a radius (R 4 ) of curvature smaller than the radius (R 3 ) of curvature of the inner portion ( 19 ).

2. Container ( 1 ) according to claim 1 , wherein, in the inwardly-inclined position, an outer portion ( 17 ) of the diaphragm ( 11 ) adjacent to the outer junction ( 12 ) is curved in radial section, with a concavity turned inwards with respect to the container ( 1 ).

3. Container ( 1 ) according to claim 2 , wherein, in the outwardly-inclined position, the diaphragm ( 11 ) is curved in radial section, with a concavity turned outwards with respect to the container ( 1 ).

4. Container ( 1 ) according to claim 2 , wherein the standing ring ( 8 ) is a high standing ring ( 8 ) provided with a frusto-conical inner wall ( 15 ) a top end of which forms the outer junction ( 12 ), whereby in the outwardly-inclined position the central portion ( 10 ) stands above the standing ring ( 8 ).

5. Container ( 1 ) according to claim 2 , wherein the diaphragm ( 11 ) has an inner diameter (D 1 ), measured on the inner junction ( 13 ), and an outer diameter (D 2 ), measured on the outer junction ( 12 ), such that their ratio (D 1 /D 2 ) is comprised between about 0.15 and about 0.45.

6. Container ( 1 ) according to claim 1 , wherein, in the outwardly-inclined position, the diaphragm ( 11 ) is curved in radial section, with a concavity turned outwards with respect to the container ( 1 ).

7. Container ( 1 ) according to claim 6 , wherein the diaphragm ( 11 ) has an outer diameter (D 2 ), measured on the outer junction ( 12 ) and wherein, in the outwardly-inclined position, a radius (R) of curvature of the diaphragm is of about half the outer diameter (D 2 ) of the diaphragm.

8. Container ( 1 ) according to claim 6 , wherein the standing ring ( 8 ) is a high standing ring ( 8 ) provided with a frusto-conical inner wall ( 15 ) a top end of which forms the outer junction ( 12 ), whereby in the outwardly-inclined position the central portion ( 10 ) stands above the standing ring ( 8 ).

9. Container ( 1 ) according to claim 6 , wherein the diaphragm ( 11 ) has an inner diameter (D 1 ), measured on the inner junction ( 13 ), and an outer diameter (D 2 ), measured on the outer junction ( 12 ), such that their ratio (D 1 /D 2 ) is between about 0.15 and about 0.45.

10. Container ( 1 ) according to claim 1 , wherein the standing ring ( 8 ) is a high standing ring ( 8 ) provided with a frusto-conical inner wall ( 15 ) a top end of which forms the outer junction ( 12 ), whereby in the outwardly-inclined position the central portion ( 10 ) stands above the standing ring ( 8 ).

11. Container ( 1 ) according to claim 10 , wherein the diaphragm ( 11 ) has an inner diameter (D 1 ), measured on the inner junction ( 13 ), and an outer diameter (D 2 ), measured on the outer junction ( 12 ), such that their ratio (D 1 /D 2 ) is between about 0.15 and about 0.45.

12. Container ( 1 ) according to claim 1 , wherein the diaphragm ( 11 ) has an inner diameter (D 1 ), measured on the inner junction ( 13 ), and an outer diameter (D 2 ), measured on the outer junction ( 12 ), such that their ratio (D 1 /D 2 ) is between about 0.15 and about 0.45.

13. Container ( 1 ) according to claim 12 , wherein the inner diameter (D 1 ) and the outer diameter (D 2 ) of the diaphragm ( 11 ) are such that their ratio (D 1 /D 2 ) is about 0.35.

14. Container ( 1 ) according to claim 1 , wherein the respective radiuses (R 3 , R 4 ) of curvature of the inner portion ( 19 ) and outer portion ( 20 ) of the diaphragm ( 11 ) are such that their ratio (R 3 /R 4 ) is between about 0.2 and 0.4.

15. Container ( 1 ) according to claim 1 , wherein the outer portion ( 20 ) of the diaphragm ( 11 ) connects to the standing ring ( 8 ) through an annular ring ( 22 ).

16. Container ( 1 ) according to claim 1 , wherein the central portion ( 10 ) has a central disc ( 23 ) and a frustoconical outer ring ( 24 ) which connects the inner portion ( 19 ) of the diaphragm ( 11 ) to the central disc ( 23 ), wherein the outer ring ( 24 ) is inclined, with respect to a line parallel to a main axis (X) of the container, by an angle A, and wherein, at the inner junction ( 13 ), a tangent to the inner portion ( 19 ) of the diaphragm ( 11 ) is inclined with respect to said line, in the outwardly-inclined position, by an angle B substantially equal to angle A.