Water drain plug

1. A water drain plug ( 10 ) for a cavity ( 16 ) in a sill of a vehicle, comprising

a base body ( 18 ) which can be inserted into an aperture ( 12 ) of the cavity ( 14 ) and has an opening ( 20 ) in which a sealing element ( 22 ) is arranged that is adapted to be moved between a closing position in which the opening ( 20 ) is tightly closed, and an openinq position in which the opening ( 20 ) is open,

wherein the sealing element ( 22 ) is mounted in the base body ( 18 ) for pivoting movement about a retaining axis ( 36 ) that extends generally perpendicular to a direction of travel of the vehicle when the water drain plug is fixed in the aperture,

the sealing element ( 22 ) in the closing position being located within the opening ( 20 ) in the base body ( 18 ) so as to rest against a sealing rim ( 40 ) and at least one centering surface ( 32 )disposed within the base body ( 18 ) to seal the opening ( 20 ),

the sealing element being arranged to move from the closing position to the opening position solely in response to gravity acting on the sealing element when the vehicle is at a standstill and to move from the opening position to the closing position in response to an air pressure difference between the cavity and an outer side of the sill,

the sealing element being urged into the closing position by the air pressure difference produced between the cavity and the outer side of the sill during travel of the vehicle.

2. The water drain plug according to claim 1 , wherein a receiving means ( 30 ) is provided on the base body ( 18 ) or on the sealing element ( 22 ), in which at least one projection provided on the sealing element ( 22 ) or on the base body ( 18 ) is mounted for pivoting movement.

3. The water drain plug according to claim 2 , wherein the receiving means ( 30 ) has a clipping or latching connection for the projection.

4. The water drain plug according to claim 1 , wherein the sealing rim ( 40 ) is arranged on an outer side of the base body ( 18 ) and the sealing element ( 22 ) is adapted to be pivoted away from the outer side into the opening position.

5. The water drain plug according to claim 1 , wherein a wind deflector ( 42 ) comprising a spoiler is provided on the base body ( 18 ).

6. The water drain plug according to claim 5 , wherein the wind deflector ( 42 ) is arranged in front of the opening ( 20 ) in the direction of trvel (F) of the vehicle when the base body ( 18 ) is mounted in the aperture ( 12 ).

7. The water drain plug according to claim 1 , wherein in the base body ( 18 ) and/or the sealing element ( 22 ) is made of a thermoplastic elastomer.

8. A water drain plug for a cavity in a sill of a vehicle, the water drain plug comprising:

a base body inserted into an aperture of the cavity; the base body including an opening; and

a sealing element pivotally mounted to the base body for pivoting movement about a retaining axis that extends generally perpendicular to a direction of travel of the vehicle when the base body is fixed n the aperture, the sealing element being configured for movement between a closing position in which the sealing element seals the opening and an opening position in which the opening is open,

the sealing element ( 22 ) in the closing position being located within the opening ( 20 ) in the base body ( 18 ) so as to rest against a sealing rim ( 40 ) and at least one centering surface ( 32 ) disposed within the base body ( 18 ) to seal the opening ( 20 ),

the sealing element being arranged to move from the closing position to the opening position solely in response to gravity acting on the sealing element when the vehicle is at a standstill and to move from the opening position to the closing position in response to an air pressure difference between the cavity and an outer side of the sill,

the sealing element being urged into the closing position by the air pressure difference produced between the cavity and the outer side of the sill during tral of the vehicle.

9. The water drain plug according to claim 8 , wherein the sealing element is held in the closing position solely by the air pressure difference between the cavity and the outer side of the sill.

10. The water drain plug according to claim 8 , wherein the sealing element is free from mechanical bias towards the opening position.

11. The water drain plug according to claim 1 , wherein the sealing element is held in the closing position solely by the air pressure difference between the cavity and the outer side of the sill.

12. The water drain plug according to claim 1 , wherein the sealing element is free from mechanical bias towards the opening position.

13. A water drain plug for a cavity in a sill of a vehicie, the water drain plug comprising:

base body including an opening and being fixed in an aperture of the cavity; and

a sealing element pivotally mounted to the base body for pivoting movement about a retaining axis that extends generally perpendicular to a direction of travel of the vehicle when the base body is fixed in the aperture, the sealing element being configured for movement between a closing position in which the sealing element seals the opening and an opening position in which the opening is open,

the sealing element ( 22 ) in the closing position being located within the opening ( 20 ) in the base body ( 18 ) so as to rest against a sealing rim ( 40 ) and at least one centering surface ( 32 ) disposed within the base body ( 18 ) to seal the opening ( 20 ),

the sealing element moving from the closing position to the opening position solely in response to the force of gravity acting on the sealing element and moving from the opening position to the closing position in response to a air pressure difference between the cavity and an outer side of the sill, the sealing element being held in the closing position solely by the air pressure difference between the cavity and an outer side of the sill.