Thermo Electron Corporation

Labsystems Oy

Tapani Pullinen

Jukka Tervamaki

Juha Telimaa

Mauno Heinonen

Kari Jarvimaki

Jouko Mikkonen

Vesa Salo

A pipette includes a housing defining a suction chamber. A piston is configured to move in the suction chamber. A first retainer mechanism includes a first threading configured to limit a motion of the piston in the suction chamber. A second retainer mechanism includes a second threading configured to limit the motion of the piston in the suction chamber, the second threading having a pitch less than a pitch of the first threading.

Adjustable pipette

The object of the invention is a ratchet wheel pipette having a body and in it a cylinder (3) and a piston (12) and a filling and dispensing arrangement to draw liquid into the cylinder and to dispense it in smaller portions with the aid of the piston. The pipette has a push rod (11) as an extension of the piston, a transmission wheel (6) in mesh with the push rod, a ratchet wheel (5) having a larger diameter than the transmission wheel and rotating with it and having a peripheral engaging surface, such as gears, and, journaled on the same shaft as the ratchet wheel, a dispensing lever (9) which is movable between an upper position and a lower position and with an attached pawl (10) engaging the engaging surface of the ratchet wheel, so that when the dispensing lever moves downwards, beginning at a certain point of the movement, the pawl engages the engaging surface of the ratchet wheel and forces the ratchet wheel and thus also the transmission wheel to rotate, and so that when the dispensing lever moves upwards the pawl does not rotate the ratchet wheel. The pipette can be used in laboratories, for instance to dispense samples or reagents.

Ratchet pipette

Growing community of inventors

Hyvinkaa, Finland

Tapani Pullinen