Manual metering device

1. A manual metering apparatus ( 1 ) comprising in particular a pipette extending along a longitudinal axis, having a dispensing mechanism ( 2 ) for dispensing a defined liquid volume, having a volume adjusting mechanism ( 3 ) for adjusting a dispensing volume, having a volume display ( 4 ) for displaying a set dispensing volume, and having an operating element ( 5 ) for operating the volume adjusting mechanism ( 3 ), wherein the operating element ( 5 ) comprises a display adjusting element ( 7 ) which is connected to the volume display ( 4 ) and a volume adjusting element ( 8 ) which is connected to the volume adjusting mechanism ( 3 ), wherein the display adjusting element ( 7 ) and the volume adjusting element ( 8 ) being connected to one another via a releasable coupling ( 9 ) such that a volume adjustment by the volume adjusting element ( 8 ) leads to a corresponding adjustment of the volume display ( 4 ) by the display adjusting element ( 7 ) and vice versa, and, wherein, with the releasable coupling ( 9 ) released, the display adjusting element ( 7 ) and the volume adjusting element ( 8 ) are adjustable independently of one another to adjust the manual metering apparatus ( 1 ), with the volume display ( 4 ) and the volume adjusting mechanism ( 3 ) being actuated independently of one another, wherein the releasable coupling ( 9 ) is a positively locking radial coupling which comprises at least one coupling element ( 12 ) and at least one mating coupling element ( 13 ), the at least one coupling element ( 12 ) being arranged on the volume adjusting element ( 8 ), and the at least one mating coupling element ( 13 ) being arranged on the display adjusting element ( 7 ), and, wherein the at least one coupling element ( 12 ) on the volume adjusting element ( 8 ) is a tooth segment ( 14 ) which is radially displaceable transversely to the longitudinal axis, and the mating coupling element ( 13 ) on the display adjusting element ( 7 ) is a mating toothing system ( 15 ) which includes a plurality of grooves parallel to the longitudinal axis, each of the grooves being configured to fit the tooth segment ( 14 ).

2. The manual metering apparatus ( 1 ) as claimed in claim 1 , wherein the manual metering apparatus ( 1 ) has a housing ( 10 ), in which at least the dispensing mechanism ( 2 ) and the volume adjusting mechanism ( 3 ) are arranged.

3. The manual metering apparatus ( 1 ) as claimed in claim 1 , wherein the volume adjusting element ( 8 ) is configured as a rotatable pushbutton such that a rotational movement of the pushbutton allows for selectively adjusting the fluid volume to be dispensed with such selection being transmitted to the volume adjusting mechanism ( 3 ), and such that axial movement of the pushbutton causes dispensing a preset fluid volume by transmitting to the dispensing mechanism ( 2 ).

4. The manual metering apparatus ( 1 ) as claimed in claim 3 , wherein the display adjusting element ( 7 ) defines a leadthrough ( 11 ) in which the volume adjusting element ( 8 ), configured as the rotatable pushbutton, is guided and arranged.

5. The manual metering apparatus ( 1 ) as claimed in claim 1 , wherein the volume adjusting element ( 8 ) comprises a sleeve ( 17 ) which, at an actuating end, has a plug-in opening ( 18 ) for a coupling pin ( 19 ) of the releasable coupling ( 9 ), wherein the at least one coupling element ( 12 ) is outwardly radially displaceable by plugging the coupling pin ( 19 ) into the plug-in opening ( 18 ), counter to a restoring force of a restoring element ( 16 ).

6. The manual metering apparatus ( 1 ) as claimed in claim 5 , wherein, on an upper side which faces away from the plug-in opening ( 18 ), the coupling pin ( 19 ) has a pressure face ( 24 ) for actuating the volume adjusting element ( 8 ).

7. The manual metering apparatus ( 1 ) as claimed in claim 1 , wherein the volume adjusting mechanism ( 3 ) has a spindle ( 25 ) with a thread ( 26 ), the dispensing mechanism ( 2 ) has a plunger ( 27 ) which can be moved in a cylinder ( 28 ) of the manual metering apparatus ( 1 ), and the volume adjusting element ( 8 ) has a mating thread ( 29 ) which fits the thread ( 26 ), the spindle ( 25 ) being connected via the thread ( 26 ) and the mating thread ( 29 ) to the volume adjusting element ( 8 ), and the spindle ( 25 ) being connected to the plunger ( 27 ), with the result that, in the case of a rotation of the volume adjusting element ( 8 ), a screwing depth between the volume adjusting element ( 8 ) and the spindle ( 25 ) and an insertion depth of the plunger ( 27 ) into the cylinder ( 28 ) can be changed, the spindle ( 25 ) being mounted non-rotatably and axially displaceably in a housing ( 10 ) of the manual metering apparatus ( 1 ).

8. The manual metering apparatus ( 1 ) as claimed in claim 1 , wherein the display adjusting element ( 7 ) is movable between a locked starting position into a volume adjusting position, wherein a volume adjustment is prevented with the display adjusting element ( 7 ) in the locked starting position with the dispensing mechanism ( 2 ) being actuatable by the volume adjusting element ( 8 ), and, wherein, at least one of the volume adjusting mechanism ( 3 ) and the volume display ( 4 ) is actuatable with the display adjusting element ( 7 ) being in the volume adjusting position.

9. The manual metering apparatus ( 1 ) as claimed in claim 1 , wherein the mating toothing system ( 15 ) has a greater axial extent than the at least one coupling element ( 12 ), so that the volume adjusting element ( 8 ) can be displaced axially relative to the display adjusting element ( 7 ) by way of the at least one coupling element ( 12 ) in order to actuate the dispensing mechanism ( 2 ), without the releasable coupling ( 9 ) being released.

10. The manual metering apparatus ( 1 ) as claimed in claim 1 , wherein the volume adjusting element ( 8 ) and the display adjusting element ( 7 ) can be rotated relative to one another in the case of the releasable coupling ( 9 ).

11. The manual metering apparatus ( 1 ) as claimed in claim 1 , wherein a gear mechanism ( 30 ) is connected between the display adjusting element ( 7 ) and the volume display ( 4 ).

12. The manual metering apparatus ( 1 ) as claimed in claim 1 , wherein the manual metering apparatus ( 1 ) has an ejection mechanism ( 33 ) for ejecting a pipette tip which is plugged onto a free shank end ( 34 ) of the manual metering apparatus ( 1 ).

13. The manual metering apparatus ( 1 ) as claimed in claim 1 , wherein the tooth segment ( 14 ) is outwardly radially displaceable counter to a restoring force of a restoring element ( 16 ).

14. The manual metering apparatus ( 1 ) as claimed in claim 13 , wherein the at least one coupling element ( 12 ) has a guide groove ( 23 ) for receiving the restoring element ( 16 ).

15. The manual metering apparatus ( 1 ) as claimed in claim 5 , wherein the at least one coupling element ( 12 ) has a projection ( 22 ), with the sleeve ( 17 ) having at least one opening ( 21 ) for the at least one coupling element ( 12 ), the projection ( 22 ) being formed to reach through the opening ( 21 ) into the interior of the sleeve ( 17 ).

16. The manual metering apparatus ( 1 ) as claimed in claim 11 , wherein the gear mechanism is one of a single-stage planetary gear mechanism or a multiple-stage planetary gear mechanism.

17. The manual metering apparatus ( 1 ) as claimed in claim 12 , wherein the ejection mechanism ( 33 ) is actuated by axial displacement of the display adjusting element ( 7 ).