Pipette with adjustable pipetting volume and locking system

A pipette (10) comprising:

• a body (20) for receiving a displacement device (22),
• the displacement device (22) comprising
• a displacement chamber (24) and
• a movable boundary element (26) for bounding a pipetting stroke of the pipette (10),
• an operating element (12) is configure to set the pipetting volume of the pipette (10) by movement of the boundary element (26) in the body (20) and the operating element is configured to perform a pipetting operation,
• a piston (28) connected to the operating element (12) and configured to be moved in the displacement chamber (24) of the displacement device (22),
• a counter (30) for displaying the set pipetting volume,
• a coupling element (32) having gear teeth (36),
• a lifting rod, wherein the coupling element is coupled to the lifting rod (21) and the operating element (21),
• a locking mechanism (40) for locking and/or unlocking volume setting comprising;
• a locking element (41), wherein the volume setting is determined by the operating element (12) by rotating the operating element (12) upon which the boundary element (26) is moved,
• a connecting element (46) which connects the locking element (41) with the coupling element (32) which connects the counter (30) with a setting mechanism (34) for moving the boundary element (26) in the displacement chamber (24),
• wherein, upon actuation of the operating element (12), the operating element (12) is configured to perform a pipetting operation, to transfer the locking mechanism (40) into a locked position and to lock adjustment of the pipetting volume by axial displacement of the operating element (12) which pushes the locking element (41) in the axial direction into the coupling element (32),
• gear teeth (48) are formed on the locking element (41) which on the axial displacement of the locking element (41) engage in gear teeth (36) of the coupling element (32) and locks rotation of the operating element (12) and displacement of the boundary element (26) of the displacement chamber (24),
• wherein an unlocked switching position of the locking mechanism (40), the coupling element (32) transmits a rotational movement of the operating element (12) configured to adjust the pipetting volume to the counter (30).