| 摘要 |
A pipette for distributing successive volumes of a liquid by repeatedly actuating a push-rod (22) is disclosed. A driving lever (26) is provided for driving in a downwards direction only a push stem (15) and a piston stem (5), wherein said lever (26) is transversal to the longitudinal axis (X) of said push stem (15) and comprises a bore (27) for the passage of said push stem therethrough with limited clearance. The push-rod (22) may move the driving lever (26), by engaging one end thereof, towards a biased position on said push stem (15), and drive the push stem downwards by a wedging action with the piston stem (5), and thereby expel a predetermined volume of liquid. The driving lever (26) is rotatably mounted about a geometrical axis (Y) intersecting at right angles the bore axis (27), substantially at half its thickness.
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