| 摘要 |
A pipette which is provided with a piston, with a toothed rack connected with the piston, with a striking pin resting against the toothed rack, and with a dosage lever mounted on the striking pin. By depressing the lever, the filled pipette can be emptied as successive doses of specified magnitude. The pipette is additionally provided with a lifting lever (20) placed at the side of the toothing, the distance of the said lever from the end of the toothed rack being adjustable (24) as desired and the said lever permitting the striking pin to push the toothed rack over a specified distance only. In this way, it is possible to adjust the magnitude of the emptying step as desired. Moreover, the toothed rack is provided with a second toothing (5), a cogwheel (7) resting against it and, at the other side, resting against a second toothed rack (11), whose top end is provided with a press knob (12). By pressing this knob downwards, the toothed dosage rack with its piston is shifted to its upper position, and the pipette is filled. |
