| 摘要 |
A repetitive pipette wherein a rack shaft (23) vertically and movably provided in a pipette body (1) is connected to a plunger (43) of a syringe unit (41), and a vertically movable and pivotable pawl member (16) repetitively moves downward and meshes with the rack shaft (23) to feed the plunger (43) downward by a predetermined feed pitch at each time, thereby effecting repetitive pipetting, and wherein the predetermined feed pitch for the rack shaft (23) can be variably set by a pipetted quantity variably setting device. A vertically movable push button (2) is provided on the pipette body (1). A rotary control knob (3) for variably setting a pipetted quantity is provided in coaxial relation to the push button (2) so as to be vertically movable together with the push button (2) as one unit and rotatable relative to the push button (2). A pawl retaining member (12) for retaining the pawl member (16) is vertically movable together with the push button (2) as one unit. A spring (13) upwardly biases the pawl retaining member (12), the push button (2), and the rotary control knob (3). A pawl stroke varying rotary cam (17) has a plurality of first cam step portions (17.1 to 17.5) for variably setting a position from which the pawl member (16) starts pivoting toward the rack shaft (23) to mesh with it. The rotary cam (17) is rotated together with the rotary control knob (3) as one unit to allow one of the first cam step portions to correspond to the pawl member (16) selectively. The pipetted quantity variably setting device includes the rotary control knob (3) and the pawl stroke varying rotary cam (17).
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