Patent ID: 7284454

Claim:
A hand-held pipette comprising: a housing provided with a chamber and internal mutually spaced first and second stops; a pipette tip in fluid communication with said chamber; a reciprocating piston arranged to coact with said chamber in aspirating and dispensing fluids into and out of said pipette tip; an actuator assembly for reciprocating said piston, said actuator assembly having an overall length subdivided into first and second sections respectively provided with first and second contact surfaces; at least one resilient member configured to urge said actuator assembly into a rest position at which said first contact surface is in contact with said first stop and said second contact surface is spaced from said second stop by a control distance, said actuator assembly being arranged to reciprocate between said rest position and an advanced position at which said second contact surface is in contact with said second stop and said first contact surface is spaced from said first stop, the stroke of said actuator assembly and the stroke of said piston being equal to said a control distance; and said actuator assembly including an adjustment mechanism configured to displace one section of said actuator assembly in relation to the other section thereof, said displacement resulting in a corresponding change in both the overall length of said actuator assembly and said control distance.