Patent ID: 8518345

Claim:
A hand-held, electronic multi-channel pipettor comprising: multiple aspiration cylinders and a plurality of repositionable pipette tip fitting assemblies, wherein each tip fitting assembly has a pipette tip mounting shaft; a handle portion and a lower portion; a first motor for controlling the movement of pistons within the multiple aspiration cylinders; a roller drum in the lower portion that rotates to move the repositionable pipette tip fitting assemblies and adjust the center line spacing between the mounting shafts; a second motor having a motor output shaft that outputs torque to rotate the roller drum and adjust the centerline spacing between the mounting shafts, wherein the centerline distance between adjacent pipette tip mounting shafts changes evenly as the roller drum is rotated by the second motor such that at least two desired tip spacing settings are settable at distances greater than or equal to a minimum tip spacing distance and less than or equal to a maximum tip spacing distance; and a user interface located on the pipettor; a microprocessor configured to control the second motor; and software that programs the microprocessor to operate the second motor to position and reposition the repositionable up fitting assemblies in response to inputs on the user interface.