Patent ID: 8297134

Claim:
A pipetting device with means ( 6 ) for detachably connecting with at least one pipette tip ( 7 ) and at least one displacement device ( 9 , 10 ) having a displacement chamber ( 9 ) and a displacement member ( 10 ) movably arranged therein, for sucking in and ejecting liquid into and out of the at least one pipette tip ( 7 ), or means for detachably connecting with at least one syringe with a cylinder and a plunger relocatable therein, a lifting rod ( 15 ) for driving the displacement member ( 10 ) or the plunger of the at least one syringe, with a driving means ( 14 ) for driving the lifting rod ( 15 ), an adjustment device ( 5 ) for adjusting the metering volume with a lead screw nut ( 17 ) and a lead screw ( 16 ), wherein one of the components lead screw nut ( 17 ) and lead screw ( 16 ) is stationary with respect to the displacement chamber ( 9 ) or the cylinder of the connected syringe, and the other component is screwable with respect to the stationary component and has a stop ( 28 ), to which a counter-stop ( 27 ) of the lifting rod ( 15 ) is related, wherein the lead screw ( 16 ) has a first external thread ( 23 . 1 ) and at least one further external thread ( 23 . 2 ) with a thread form shaped different than that of the first external thread ( 23 . 1 ), and the lead screw nut ( 17 ) has at least one related internal thread ( 24 ), and wherein on the further external thread ( 23 . 2 ) of the lead screw ( 16 ) the lead screw nut ( 17 ) features at least in parts a distance (d) to the lead screw ( 16 ) in the radial direction (R) to the axis (A) of the lead screw ( 16 ) in the level (h) of the outer diameter and/or inner diameter of the external thread ( 23 . 2 , 23 ) of the lead screw ( 16 ).