Abstract: A plunger lift pipet for a slip-on pipet tip which includes adjusting mechanism for changing the travel of the plunger, display mechanism for the liquid volume pipetted each time, disengageable coupling mechanism between the adjusting mechanism and the display mechanism for changing a pipet correction factor determining the relation between the travel of the plunger and the indicated liquid volume, the coupling mechanism positively connecting to each other the adjusting mechanism and the display mechanism and switching mechanism for completely disengaging the coupling mechanism and changing the pipet correction factor by setting the adjustment mechanism being provided.

Abstract: A pipette device, comprising a housing, an actuating element projecting from the upper end of this housing, a cylinder, a hollow piston moveable in this cylinder for displacing an air volume, a rod connecting this piston to this actuating element which is depressed against spring force to displace this piston, and an adapter cone for receiving replaceable pipette tips communicating with this cylinder. According to the invention the hollow piston comprises an outer tubular shell and an inner support which is preferably made of plastic material and to which the actuating element is connected by a coupling. The invention particularly refers to providing a variety of shells made of different materials which can be easily replaced.

Abstract: A pipetting device is provided at its top with an actuating element, which is depressible against spring action and which is connected to a piston, which is movable in a cylinder to move an air volume. The cylinder communicates with an opening in a particularly conical pipette connector, on which a pipette tip which open-topped and open-bottomed is adapted to be slidably fitted. The pipettable volume is adapted to be adjusted by a rotation of the actuating element. The actuating element consists of a knob, which is axially movable to establish and separate a detent element joint between a screw and a nut which is fixed in the housing. By a rotation of the actuating knob the screw can be rotated in said nut to impart an axial movement to a piston rod, which is connected to the piston so that the latter is infinitely adjustable in known manner. At least one of the detent elements which constitute the detent element joint comprises teeth which are spaced around the center line of the pipetting device.

Abstract: A pipetting device serves to hold and actuate a detachably mounted syringe having a syringe body and a piston. The device is provided with means for adjusting the volumetric capacity of the syringe. The device comprises two racks and a pinion which is in mesh with both said racks and operable to move them in mutually opposite directions. The racks are connected to respective sliders, one of which is connected to a rod for actuating the piston of the syringe. A single actuating lever is provided for actuating the piston and is connected to the sliders by an actuating mechanism, which comprises a positively actuated transverse slider, which constitutes a stop member and in response to an automatic resetting of the actuating lever to its initial position is moved from the path of one of said sliders into the path of the other.

Abstract: A pipette device having an elongate casing with a handle portion at its upper end and an actuating button slidably mounted in the casing and projecting outwardly from the casing at the upper surface of the handle portion. The actuating button is coupled to a piston that is slidably movable within a cylinder disposed within the casing. The lower end of the casing mounts a conical adapter member for receiving replaceable pipette tip members. The actuating button is urged upwardly so that it projects from the upper end of the casing by spring means. A detent means within the casing allows to depress the actuating button into the casing against the spring means by a first distance corresponding to the displacement of the pipetting volume.