Filling nozzle

1 . A filling nozzle for delivering a fluid, comprising an inlet ( 13 ) for connection of a fluid feed line, an outlet ( 14 ), a main conduit ( 15 ) connecting the inlet ( 13 ) to the outlet ( 14 ), a main valve device ( 16 ) for controlling a flow of fluid through the main conduit ( 15 ), a control lever ( 17 ) for actuating the main valve device ( 16 ), an automatic safety shut-off designed to move the main valve device ( 16 ) to a closed position independently of a position of the control lever ( 17 ) when a fluid pressure at the inlet ( 13 ) falls below a minimum value, and comprising a preloading device ( 18 ) which preloads the main valve device ( 16 ) into the closed position and effects a variable opening cross section of the main valve device ( 16 ) depending on a fluid pressure at the inlet ( 13 ), characterized in that

the preloading device ( 18 ) is designed to produce a discontinuous opening characteristic of the main valve device ( 16 ) in such a way that a closing force acting on the main valve device ( 16 ) is reduced in a first opening cross-sectional range extending from the closed position of the main valve device ( 16 ) to a limit opening cross section.

2 . The filling nozzle as claimed in claim 1 , wherein the preloading device ( 18 ) cooperates with the main valve device ( 16 ) such that

the limit opening cross section ranges between 1 mm 2 and 12 mm 2 and/or

a minimum pressure which is required for opening the main valve device ranges between 0.01 bar and 0.5 bar.

3 . The filling nozzle as claimed in claim 2 , wherein the minimum pressure which is required for opening the main valve device ranges between 0.05 bar and 0.3 bar.

4 . The filling nozzle as claimed in claim 1 , wherein the preloading device ( 18 ) cooperates with the main valve device ( 16 ) such that a pressure threshold value from which the opening cross section exceeds the limit opening cross section ranges between 0.075 bar and 0.5 bar.

5 . The filling nozzle as claimed in claim 4 , wherein the pressure threshold value is at least 5% greater than a minimum pressure which is required for opening the main valve device.

6 . The filling nozzle as claimed in claim 4 , wherein the pressure threshold value is at least 50% greater than a minimum pressure which is required for opening the main valve device.

7 . The filling nozzle as claimed in claim 1 , wherein the main valve device ( 16 ) has a main valve body ( 20 ), a main valve seat ( 23 ), a pressure reduction conduit ( 21 ) and a pressure reduction valve body ( 22 ) which is configured for closing the pressure reduction conduit ( 21 ), wherein the preloading device ( 18 ) is designed to urge the main valve body ( 20 ) and the pressure reduction valve body ( 22 ) independently of one another into a closed position, wherein a change in the opening cross section of the main valve device ( 16 ) in the first opening cross-sectional range is effected by a movement of the pressure reduction valve body ( 22 ), wherein a change in the opening cross section of the main valve device ( 16 ) beyond the limit opening cross section is effected by a movement of the main valve body ( 20 ) relative to the main valve seat ( 23 ).

8 . The filling nozzle as claimed in claim 7 , wherein the pressure reduction conduit runs through the main valve body ( 20 ).

9 . The filling nozzle as claimed in claim 7 , wherein the preloading device ( 18 ) has a first restoring element ( 18 a ) for urging the main valve body ( 20 ) into the closed position and a second restoring element ( 18 b ) for urging the pressure reduction valve body ( 22 ) into the closed position.

10 . The filling nozzle as claimed in claim 1 , wherein the main valve device ( 16 ) comprises a main valve body ( 20 ′, 20 ″) which is preloaded by the preloading device ( 18 ) against a main valve seat ( 23 ) into a closed position, wherein the first opening cross-sectional range corresponds to a first adjustment range of the main valve body ( 20 ′, 20 ″) and a second opening cross-sectional range beyond the limit opening cross section corresponds to a second adjustment range of the main valve body ( 20 ′, 20 ″) subsequent to the first adjustment range, wherein the discontinuous opening characteristic is implemented by the preloading device ( 18 ) having a smaller restoring constant in the first adjustment range than in the second adjustment range.

11 . The filling nozzle as claimed in claim 10 , wherein the preloading device ( 18 ) comprises a first restoring element ( 18 a ) and a second restoring element ( 18 c ), wherein a movement of the main valve body ( 20 ′) in the first adjustment range in the opening direction takes place primarily counter to a restoring force of the second restoring element ( 18 c ), and wherein a movement of the main valve body ( 20 ′) in the second adjustment range in the opening direction takes place primarily; counter to a restoring force of the first restoring element ( 18 a ).

12 . The filling nozzle as claimed in claim 11 , wherein the first restoring element ( 18 a ) preloads the main valve body ( 20 ′) relative to a displaceable holding element ( 24 ), wherein the second restoring element ( 18 c ) preloads the displaceable holding element ( 24 ) relative to the main valve seat ( 23 ) of the main valve device ( 16 ).

13 . The filling nozzle as claimed in claim 12 , wherein a displaceability of the displaceable holding element ( 24 ) relative to the main valve seat ( 23 ) is delimited by a first stop ( 26 ).

14 . The filling nozzle as claimed in claim 13 , wherein a displaceability of the displaceable holding element ( 24 ) relative to the main valve body ( 20 ′) is delimited by the second stop ( 35 ).

15 . The filling nozzle as claimed in claim 11 , wherein the preloading device ( 18 ) comprises a first restoring element ( 18 a ) and a second restoring element ( 18 c ), wherein a movement of the main valve body ( 20 ′) in the first adjustment range in the opening direction takes place exclusively counter to a restoring force of the second restoring element ( 18 c ), and wherein a movement of the main valve body ( 20 ′) in the second adjustment range in the opening direction takes place exclusively counter to a restoring force of the first restoring element ( 18 a ).

16 . The filling nozzle as claimed in claim 10 , wherein the preloading device ( 18 ) comprises:

a first restoring element ( 18 a ) with a first restoring constant which urges the main valve body ( 20 ″) into the closed position relative to the main valve seat ( 23 ), and a second restoring element ( 18 d ) with a second restoring constant which urges the main valve body ( 20 ″) in the opening direction relative to the main valve seat ( 23 ).

17 . The filling nozzle as claimed in claim 16 , wherein the restoring constant of the preloading device ( 18 ) in the first adjustment range results from a combination of restoring constants of the first and second restoring elements ( 18 a , 18 d ) and wherein the restoring constant of the preloading device ( 18 ) in the second adjustment range results only from the restoring constant of the first restoring element ( 18 a ).

18 . The filling nozzle as claimed in claim 16 , wherein a restoring force of the first restoring element ( 18 a ), which acts in the first adjustment range on the main valve body ( 20 ″), is greater than a restoring force of the second restoring element ( 18 d ) which acts in the first adjustment range on the main valve body ( 20 ″).

19 . The filling nozzle as claimed in one of claim 16 , wherein the second restoring element ( 18 d ) has a first end and an opposing second end in a deflection direction, wherein the first end is fixed to the main valve body ( 20 ″) and wherein during a movement of the main valve body ( 20 ″) in the first adjustment range the second end bears against a stop ( 25 ) which is fixed relative to the main valve seat ( 23 ), and wherein during a movement of the main valve body ( 20 ″) in the second adjustment range the second end is released from the stop ( 25 ), wherein a deflection of the second end of the second restoring element ( 18 d ) in the upstream direction is preferably delimited by a limit projection ( 38 ) which is fixed to the main valve body ( 20 ″).

20 . A filling pump with a feed pump for delivering a fluid and with a filling hose which connects the feed pump to a filling nozzle as claimed in claim 1 .