| 摘要 |
A repeating pipetting device includes an elongated housing, a flange holder at one end of the housing for holding the flange of a syringe, a coupling assembly for connection to the plunger of the syringe, and a toothed rack connected to the coupling assembly and longitudinally reciprocable relative to the flange holder. A pawl is engageable with the teeth of the rack and is operable to advance the rack toward the flange holder in a succession of steps. An operating lever movable back and forth in the elongated direction of the housing, intermittently operates the pawl, and a return lever retracts the rack from the flange holder. A tongue-like cover or slide is provided within the device and covers the rack for a part of its length. The cover is slidably adjustable along the rack and has a portion engageable by the pawl which limits the extent to which the rack can be advanced by the pawl in each step.
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