Pipetting head for a liquid dispensing apparatus for use with an array of pipettes

A pipetting head for a liquid dispensing apparatus for use with an array of pipettes each having a pipette tip and a plunger disposed within the pipette tip, the pipetting head comprising:

• a pipette tip connection mechanism with a plurality of tip mounts for holding the pipette tips of the array of pipettes during use;
• and
• a plunger connection mechanism with a plurality of plunger mounts for holding the plungers of the array of pipettes during use,
• wherein:
• each of the plurality of plunger mounts has a radially extending feature on its inner surface which is configured to form one half of a snap-fit connection, and wherein the plunger connection mechanism is a plunger clamping mechanism further comprising:
• a plurality of plunger clamping members each associated with one of the plurality of plunger mounts and each having a clamping region, and
• a plunger clamping drive mechanism comprising an actuator operable to drive relative movement between the plunger mounts and the plunger clamping members in an axial direction to selectively engage the plunger clamping mechanism by moving it between a clamp position and a release position,
• wherein the plurality of plunger mounts comprises a plurality of axially extending sleeves and wherein the plurality of plunger clamping members comprises a plurality of axially extending clamping rods which define the clamping region and extend inside the plurality of axially extending sleeves when the plunger clamping mechanism is engaged, such that the clamping region of each plunger clamping rod is axially adjacent to the radially extending feature on the inner surface of its associated plunger mount when the plunger clamping mechanism is in the clamp position, and the clamping region of each plunger clamping rod is axially offset from the radially extending feature on the inner surface of its associated plunger mount when the plunger clamping mechanism is in the release position, and wherein a radial clearance is provided between the plurality of clamping rods and the plurality of plunger mounts when the plunger clamping mechanism is in the clamp position.