GB2637770A

GB2637770A - Pipetting head for a liquid dispensing apparatus

Info

Publication number: GB2637770A
Application number: GB2401428.4A
Authority: GB
Inventors: Gordon Douglas Anthony; Marcus Molony David; Borthwick Maximilian
Original assignee: SPT Labtech Ltd
Current assignee: SPT Labtech Ltd
Priority date: 2024-02-02
Filing date: 2024-02-02
Publication date: 2025-08-06
Also published as: WO2025163325A1; GB202401428D0

Abstract

A pipetting head 100 comprises an engagement mechanism actuating arrangement and a plurality of engagement extensions 400 for engaging a pipette tip carrier 30 to draw the pipetting head 100 toward the pipette tip carrier 30, the extensions are movable between a first position (figures 16-20) in which the engagement extensions extend beyond an array of pipette tip mounts in the dispensing direction and a second position (figure 21) in which the engagement extensions are retracted for a dispensing operation. The engagement extensions may comprise lateral projections 412 which are actuated towards a central plane C and a plan of the array of pipette tip mounts P. An engagement portion 70 for engaging with the extensions is placed on a pipette tip carrier, an adapter plate or a deck (70a-c, figure 5).

Description

PIPETTING HEAD FOR A LIQUID DISPENSING APPARATUS FIELD OF THE INVENTION

The present invention relates to a pipetting head for a liquid dispensing apparatus for use with an array of pipette tips.

BACKGROUND OF THE INVENTION

It is known to use an automated machine, such as a liquid dispensing apparatus, to aspirate or dispense a liquid sample from a pipette tip. Such machines often use an array of removable pipette tips mounted on pipette mounts of the machine. Typically, an array of removable pipette tips is held in a pipette tip carrier beneath the pipetting head and are connected to the pipetting head by moving the pipetting head in position over the pipette tip carrier and lowering the pipetting head to engage the array of removable pipette tips with the pipette mounts. Once the pipette tips are connected to the pipette mounts, the pipetting head can perform liquid dispensing and/or aspirating operations as desired.

The pipette tips are typically received in the pipette mounts by a push-fit or snap-fit connection. This requires a large force to mount the pipette tips on to the pipette mounts. The pipetting head and related actuators are therefore often large and of substantial construction so as to be able to generate sufficient force to mount the pipette tips onto the pipette mounts. The inventors have identified problems with known pipetting heads for liquid dispensing apparatuses.

There is a need for an improved pipetting head and pipetting system. SUMMARY OF THE INVENTION A first aspect of the invention provides a pipetting head for a liquid dispensing apparatus, for use with an array of pipette tips, the pipetting head comprising one or more of: a pipetting arrangement comprising an array of pipette tip mounts, wherein the pipetting arrangement is arranged to retain the array of pipette tips to dispense liquid from the tips in a dispensing direction of the pipetting head, a tip engagement mechanism comprising an engagement mechanism actuating arrangement arranged to a non-dispensing side of the pipette tip mounts, and a plurality of engagement extensions connected to the engagement mechanism actuating arrangement, comprising engagement features arranged for engaging a pipette tip carrier to draw the pipetting head toward the pipette tip carrier, and being moveable between a first position in which the engagement extensions extend beyond the array of pipette tip mounts in the dispensing direction and a second position in which the engagement extensions are retracted for a dispensing operation.

Optionally, the engagement features comprise projections that extend laterally from the engagement extensions.

Optionally, the projections extend inwardly toward a central plane of the pipetting arrangement extending in the pipetting direction of the pipetting arrangement.

Optionally, the engagement mechanism actuating arrangement is arranged to actuate the engagement extensions to draw them laterally, into an engaged configuration, preferably to move or draw them inwardly toward a central plane of the pipetting arrangement extending in the pipetting direction of the pipetting arrangement.

Optionally, the engagement mechanism actuating arrangement is arranged to actuate the engagement extensions to draw them toward the plane of the array of pipette tip mounts after actuating them inwardly toward a central plane of the pipetting arrangement.

Optionally, the engagement mechanism actuating arrangement is arranged to actuate a single actuator to actuate the engagement extensions.

Optionally, the engagement mechanism actuating arrangement is configured to actuate the engagement extensions using a pipetting actuator, wherein the pipetting actuator is also arranged to be actuated to dispense fluid through the pipette tips in a pipetting operation.

Optionally, the engagement mechanism actuating arrangement further comprises a second actuator configured to retract the engagement extensions back from the dispensing side of the array of pipette tip mounts.

Optionally, the pipetting head further comprises at least one linear guide member oriented in the dispensing direction, wherein the engagement extensions are mounted to slide along the linear guide member to move between the first and second positions.

Optionally, the pipetting head further comprises a plunger mount arranged to actuate an array of plunger shafts to dispense liquid through the pipette tips when the pipette tips are mounted to the pipette tip mounts, wherein the plunger mount is arranged to slide on the linear track.

Optionally, the movement of the engagement extensions relative to the plunger mount on the linear guide member causes the engagement extensions to be drawn inwardly towards a central plane of the pipetting arrangement, the central plane extending in the pipetting direction of the pipetting arrangement.

Optionally, the engagement mechanism actuation arrangement comprises at least one lateral actuation member, wherein the lateral actuation member is arranged to apply a lateral force to the engagement extensions when the engagement extensions are moved longitudinally along the guide rail relative to the plunger mount.

Optionally, the engagement extensions comprise substantially planar members extending in a dispensing direction of the pipetting head.

Optionally, the pipette tip carrier is one of: a pipette tip box, a tip adapter plate or a deck.

A further aspect of the invention provides a method of engaging a pipetting head for a liquid dispensing apparatus with an array of pipette tips, the method comprising one of more of the steps of: providing a pipetting head as described herein, providing a pipette tip carrier carrying an array of pipette tips below the pipetting head, positioning the pipetting head over the pipette tip carrier such that the array of pipette tip mounts is aligned with the array of removable pipettes, actuating the engagement mechanism actuating arrangement to translate the engagement extensions beyond the pipette tip mounts, engaging the engagement features of the engagement extensions with the pipette tip carrier, and actuating the engagement mechanism actuating arrangement to draw the engagement extensions back towards the pipette tip mounts to advance the pipetting head towards the pipette tip carrier.

A pipette tip carrier for use with the pipetting head described herein may comprise one or more of the following features: a laterally extending array of pipette tip holders, arranged in a laterally extending plane of the pipette tip carrier, and arranged to receive pipette tips; the pipette tip holders comprising reaction points or surfaces which are oriented at least partially in a reaction direction, which extends perpendicularly to the lateral plane, for reacting a tip engagement force that acts perpendicularly to the laterally extending plane when the pipette tips are pressed into a pipetting head carrier; and/or at least one engagement feature, comprising a recess, edge, lip or opening, providing an engageable edge facing in a direction opposite to the reaction direction, for engagement by an engagement feature provided on a pipette tip engagement mechanism of the pipetting head, to draw the pipetting head toward the carrier. The pipette tip carrier may be a pipette tip box.

A pipette tip carrier adapter plate, arranged for mounting to a deck of a pipetting system to secure a pipette tip carrier in relation to the deck, may comprise one or more of the following features: attachment features for attaching the adapter plate to the deck; a pipette tip carrier receiving surface extending in a lateral plane and comprising securing features for receiving the pipette tip carrier and securing the pipette tip carrier against movement in at least a lateral direction with respect to the deck; and/or at least one engagement feature, comprising a recess, edge, lip or opening, providing an engageable edge facing in a direction opposite to the carrier receiving surface, for engagement by a lateral projection provided on a pipette tip engagement mechanism of a pipetting head, to draw the pipetting head toward the carrier when mounted to the adapter plate.

A deck of or for a pipetting system comprising a pipetting head configured for use with detachable pipette tips as described herein, may comprise one or more of the following features: a carrier receiving surface comprising attachment features for attaching a pipette tip carrier to the deck and securing the pipette tip carrier against movement in at least a lateral direction with respect to the deck; and/or at least one engagement feature, comprising a recess, edge, lip or opening, providing an engageable edge facing in a direction opposite to the carrier receiving surface, for engagement by a lateral projection provided on a pipette tip engagement mechanism of a pipetting head, to draw the pipetting head toward the carrier when mounted to the adapter plate.

The engagement feature of the pipette tip carrier is advantageously disposed at or below the array of pipette tip holders, i.e. in a plane of the array of pipette tip holders, or below the plane of the array of pipette tip holders, or to side of the plane of the array of pipette tip holders that is away from an insertion direction of the pipette tips. The insertion direction is the direction in which the pipette tips are inserted into the pipetting head.

A further aspect of the invention provides a pipetting system comprising one or more of: a pipetting head for a liquid dispensing apparatus and a carrier, the pipetting head comprising an array of pipette tip mounts arranged in a laterally extending array and configured to hold an array of pipette tips to dispense liquid therethrough; and a pipette tip engagement mechanism, arranged to draw the pipetting head toward the carrier to engage pipette tips held in the carrier in the pipette tip mounts, the carrier comprising a laterally extending array of pipette tip holders arranged to receive pipette tips for engagement with the pipetting head, wherein the pipette tip engagement mechanism and the carrier preferably comprise an engagement interface configured to be engageable at a plurality of different relative lateral positions of the pipetting head and the carrier, such that the pipette tip engagement mechanism can draw the pipetting head towards the carrier at the plurality of different relative lateral positions, to cause different respective numbers of pipette tip holders to align with respective tip mounts, for engaging different numbers of pipette tips in the array of pipette tip mounts.

Optionally, the pipetting head further comprises a plurality of engagement extensions connected to the pipette tip engagement mechanism, wherein the engagement extensions comprise engagement features arranged for engaging the carrier, wherein the engagement extensions are positionable at different relative positions along a length of the carrier.

Optionally, the engagement features comprise projections that project laterally from the engagement extensions.

Optionally, the projections project inwardly towards a central plane of the pipetting head, the central plane extending perpendicularly to the array of pipette tip mounts.

Optionally, the pipetting system comprises at least one carrier engagement feature, arranged to be engaged by the engagement features of the engagement extensions, to draw the pipetting head and the carrier toward one another. The carrier engagement feature can comprise a longitudinally-facing edge or surface, arranged to face in the dispensing direction of the head, to enable the pipetting head to be drawn toward the pipette tip holders by the engagement features of the engagement extensions. The carrier engagement feature may comprise a recess, a projection, a through hole or an overhang, for example. The carrier engagement feature may be formed in the carrier, in a carrier adapter plate for mounting the carrier to a deck, or in a deck to which the carrier is mounted.

Optionally, the pipette tip carrier engagement feature projects laterally relative to the carrier, wherein the engagement extensions are arranged to engage with the carrier engagement feature, the carrier engagement feature preferably being formed in one or more of: the carrier, a carrier adapter plate for mounting the carrier to a deck, or a deck to which the carrier is to be mounted.

Optionally, the or each carrier engagement feature extends along a substantial portion of a length of a side of the carrier so that the engagement extensions can engage the carrier engagement feature at different relative positions along the length of the carrier.

Optionally, the pipette tip engagement mechanism comprises an actuator to position the pipetting head relative to the position of the carrier.

Optionally, the pipette tip engagement mechanism is arranged to actuate the engagement extensions to draw them inwardly toward a central plane of the pipetting head extending in a pipetting direction of the pipetting head so as to engage the carrier.

Optionally, the pipette tip engagement mechanism is arranged to actuate the engagement extensions to draw them toward the plane of the array of pipette tip mounts after actuating them inwardly toward a central plane of the pipetting arrangement extending in a pipetting direction of the pipetting arrangement.

Optionally, the overhang is formed in one of: a pipette tip box, a tip adapter plate or a deck.

A further aspect of the invention provides a pipette tip carrier, a pipette tip box, a tip adapter plate or a deck, which may be for use in the system described herein, and which may comprise a carrier engagement feature comprising a recess, edge, lip or opening, providing an engageable edge facing in a defined direction, which may be the dispensing direction, so as to be engageable by a hook provided on a pipette tip engagement mechanism of the pipetting head, to draw the pipetting head toward the carrier. The engageable edge may face in an opposite direction to the pipette tip holders, so that it can be engaged to draw pipette tips held in the pipette tip holders in a direction of the pipette tip holders. Such a configuration can allow the pipette tips held in the pipette tip holders to be drawn toward a pipetting head as described herein, to engage the pipette tips in pipette tip mounts of a pipetting head described herein.

A further aspect of the invention provides a pipetting head for a liquid dispensing apparatus, for use with an array of pipette tips, the pipetting head comprising one or more of: a pipetting arrangement comprising an array of pipette tip mounts arranged to retain the array of pipette tips to dispense liquid from the pipette tips in a dispensing direction of the pipetting head, a plunger actuation member arranged to actuate an array of plungers to dispense liquid via pipette tips when engaged with the pipette tip mounts, at least one linear guide member extending in the dispensing direction of the pipetting head, the plunger actuation member being slidably mounted to the at least one linear guide member via a plurality of bearing members, the bearing members being spaced from one another along the linear guide members in the dispensing direction.

Optionally, the plunger actuation member is stabilised against misalignment caused by forces applied out of alignment with the linear guide member by the bearing members being spaced from one another along the linear guide member in the dispensing direction.

Optionally, the plunger actuation member is arranged to be able to actuate a pipette tip engagement mechanism, wherein the pipette tip engagement mechanism is arranged for drawing the pipetting head toward a pipette tip carrier to engage an array of pipette tips with the array of pipette tip mounts.

Optionally, the pipetting head further comprising an engagement mechanism having an engagement mechanism actuation member and a plurality of engagement extensions arranged to be extendable beyond the array of pipette tip mounts in a dispensing direction, the engagement actuation member being slidably mounted to the at least one guide member.

Optionally, the pipetting head further comprising an engagement mechanism actuating arrangement arranged to a non-dispensing side of the array of pipette tip mounts.

Optionally, the pipetting head may further comprise a plurality of engagement extensions connected to the engagement mechanism actuation arrangement, comprising engagement features arranged for engaging a pipette tip carrier, and being moveable between a first position in which the engagement extensions extend beyond the array of pipette tip mounts in the dispensing direction and a second position in which the engagement extensions are retracted for a dispensing operation.

A further aspect of the present invention provides a method of operating a pipetting head for a liquid apparatus, the method comprising one or more of the steps of: providing a pipetting head as described herein, providing a pipette tip carrier carrying an array of pipette tips below the pipetting head, positioning the pipetting head over the pipette tip carrier such that the array of pipette tip mounts is aligned with the array of removable pipettes, engaging the array of pipette tips in the pipetting tip mounts by movement of the plunger actuation member along the linear guide member; and sliding the plunger actuation member along the linear guide member in the dispensing direction so as to dispense liquid via the pipette tips.

While a range of features and embodiments are described in the above statements and in the following description, it will be appreciated that, in view of the technical benefits that can be derived from each feature, both alone and in combination, any or all of the above features may be beneficially combined, in any combination to realise advantages of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of examples embodying the present disclosure will be further described below, by way of example only, with reference to the accompanying drawings in which: FIGURE 1 is a front view of a liquid dispensing apparatus with a pipetting

head in accordance with the present disclosure;

FIGURE 2 is a perspective view of a pipetting head in accordance with the present disclosure; FIGURE 3 is a top-down view of an exemplary pipette tip carrier; FIGURE 4 is a perspective view of an exemplary pipette tip carrier; FIGURE 5 is a front view of the pipetting head of FIGURE 2; FIGURE 6 is a perspective view of a portion of the pipetting head of FIGURE 2, in which the bearing members are shown in more detail; FIGURE 7 is a front view of a portion of the pipetting head of FIGURE 2, in which the plunger drive mechanism is shown in more detail; FIGURE 8A is a perspective view of the plunger drive mechanism of FIGURE 7, shown in more detail; FIGURE 8B is a perspective view of a portion of the pipetting head of FIGURE 2, in which the engagement mechanism actuating arrangement is shown in more detail; FIGURE 9 is a perspective view of a portion of the pipetting head of FIGURE 2, in which the lateral actuating arrangement is shown in more detail; FIGURE 10 is a front view of the pipetting head of FIGURE 2, in which the pipettes are not received in the pipette tip mounts; FIGURE 11 is a front view of the pipetting head of FIGURE 2, in which the pipettes are received in the pipette tip mounts; FIGURE 12A is a front view of the pipetting head of FIGURE 2, in which the lateral positioning of the pipetting head relative to the pipette tip carrier has been altered; FIGURE 12B is a further front view of the pipetting head of FIGURE 2, in which the lateral positioning of the pipetting head relative to the pipette tip carrier has been further altered; FIGURE 13 is a schematic flow diagram depicting a method of loading pipette tips into the pipetting head; and FIGURES 14 to 21 illustrate the configuration of the apparatus at the different steps of the method described in relation to FIGURE 13.

DETAILED DESCRIPTION

Figure 1 shows a liquid dispensing apparatus 10 for use with an array of pipette tips. The liquid dispensing apparatus 10 comprises a pipetting head 100 that is arranged to receive a plurality of pipette tips 20 carried in a pipette tip carrier 30. The pipetting head 100 and the pipette tip carrier 30 form a pipetting system 1 for use with pipette tips 20. The apparatus 10 may also comprise a main body 12 with a deck 14. The deck 14 has a substantially horizontal upper surface 16 arranged to receive the pipette tip carrier 30. The deck 14 can be located on a height-adjustable support structure 18 which enables the height of deck 14 to be varied as required. The pipetting head 100 is positioned above the deck 14.

The apparatus 10 will generally be used in the orientation shown in Figure 1.

References to upward and downward directions or to an axial direction therefore refer to movement along the axis marked Z in Figure 1. This is also the direction in which dispensing via the pipette tips occurs -i.e. pipetting usually dispenses liquid in a vertical direction and so the direction of axis Z can also be considered the dispensing direction 5. References to a vertical direction, or to a height, also therefore refer to dimensions or movement along the axis marked Z in Figure 1. References to lateral or transverse directions refer to movement in the directions marked X (width) and Y (depth) in Figure 1. The apparatus comprises X, Y and/or Z actuators to move the pipetting head 100 relative to deck 14 to carry out pipetting operations, such as picking up pipetting tips at a first location, aspirating samples from a second location and dispensing samples into well plates in a further location on the deck, to implement liquid pipetting procedures.

A perspective view of the pipetting head 100 which may be used in apparatus such as shown in Figure 1 is shown in greater detail in Figure 2. The pipetting head 100 is configured to receive and hold an array of pipette tips 20. The pipette tips 20 may be a receptacle for receiving and/or containing a sample of fluid, or a sample of liquid. As shown in more detail in Figures 10 and 11. The pipette tips 20 are substantially elongate and extend between a proximal end 20b and a distal end 20a. The pipette tip 20 may be substantially or entirely hollow.

The pipette tips 20 each comprise a fluid cavity that may be configured to receive and/or retain a fluid, such as an air gap or sample fluid. The pipette tip 20 may comprise or consist of polymeric material. The pipette tip 20 may comprise or consist of a homogenous material. The pipette tip 20 may comprise or consist of a translucent or transparent material. The pipette tips 20 may further comprise a plunger (not shown), which may be actuated by plunger shafts 232 of the pipetting head.

Figures 3 and 4 show top-down and perspective views of an exemplary pipette tip carrier 30. The pipette tips 20 are provided in the pipette tip carrier 30.

In the example shown in Figures 3 and 4, the pipette tip carrier 30 is in the form of a pipette tip box 30. However, in other examples, the pipette tip carrier 30 may comprise a carrier adapter plate 30a for adapting its lower side to be secured to the deck 14, or may be formed in the deck 14. The pipette tip carrier 30 has a width W that extends laterally along the pipette tip carrier 30, and a length L that extends longitudinally along the pipette tip carrier 30. The length L and width W of the carrier may be substantially the same. The pipette tip carrier 30 comprises a laterally extending array 32 of pipette tip holders 34. The laterally extending array 32 of pipette tip holders 34 is formed of rows R and columns C. As shown in Figure 3, the rows R extend along the width W of the pipette tip carrier 30 and the columns C that extend along the length L of the pipette tip carrier 30.

The carrier may be made from or may comprise a mouldable, injection mouldable, blow mouldable or other formable material, suitable for high volume manufacture. Such materials could include plastics, wood fibres, recycled plastics of fibres, or other suitable reusable materials. Other materials such as metals could be used. The carrier may be configured to receive a range of numbers of pipette tips, preferably a square or rectangular number of pipette tips (i.e. one which can form a regular rectangular or square array of pipette tips), such as 4, 8, 16, and any integer number up to 96 or 384 tips, or more. Such numbers can typically be used with known laboratory sample handling systems. The engagement features 70a, 70b, 70c, may be symmetrical about a centre plane of the carrier, and may extend along a proportion of its length. The proportion may advantageously be 1/4 or more, 3/4 or more, 8/10 or more, of the length of a side of the pipette tip carrier, or substantially the whole of the side of a pipette tip carrier, or more than the side of a pipette tip carrier, to allow a full array of tips to be engaged with the head in a single operation. The engagement features may be provided along the edge in a substantially linear array (which may be continuous or segmented) to allow engagement by in a plurality of different lateral positions by the more flexible column/row number selection. Any of the engagement features for engagement by the pipetting head described may be provided on the deck 14 as shown by 70c in Figure 5, on the adapter plate as indicated by 70b in Figure 5, or on the carrier as indicated by 70a in Figure 5.

The pipette tip carrier 30 may comprise one or more side walls 37 and/or may comprise an upper surface 35 in which pipette holders 34 are provided as openings or cavities in the upper surface 35. The pipette tip holders can comprise one or more reaction points or surfaces 39 to reacting forces applied to the pipette tips on insertion into the pipetting head.

Adapter plate 30a is preferably formed in such a way as to be able to secure the carrier 30 to the deck 14, at least to ensure lateral alignment of the pipette tip carrier on the deck 14. The adapter plate can be provided with laterally facing features on its surface or sides, to engage the sides or bottom of the pipette tip carrier and prevent lateral movement. Such features could include for example a projection 30b arranged to engage one or more inner or outer sides or surface or edges of the carrier 30, or any other upward projection or recess arranged to engage a corresponding projection or recess on the carrier 30. Other securing means may be provided to prevent the pipette carrier 30 from lifting off the deck 14, such as friction fit, push fit or active retaining features such as clips, tabs, screws, or other retainers, to adapt and retain the pipette tip carrier to the deck 14 if desired. Any suitable attachment system of features 15 can be used to secure the adapter plate 30a to the deck 14, such as clips, slide-fit, screws, bolts, pins or clips. Any features for securing the pipette tip carrier 30 described as comprised in the adapter plate 30a may alternatively be comprised in a deck 14 of the pipetting system.

A plurality of pipette tips 20 may be received in the laterally extending array 32 of pipette tip holders 34 in any suitable arrangement. For example, the laterally extending array 32 may comprise a plurality of tips 20 arranged in a single row R, a plurality of rows R, arranged in a single column C, or in a plurality of columns. The laterally extending array 32 may comprise pipette tips 20 arranged in partially filled rows R and/or columns C. The laterally extending array 32 may have an equal number of tips in each row R and/or in each column C. Each pipette tip holder 34 is arranged to receive a respective pipette tip 20. The pipetting tip holders 34 has an upwardly facing opening 38 configured to receive the pipette tips 20 and are arranged to support the pipette tips 20 and maintain them in a fixed array by preventing their lateral movement. The upwardly facing opening 38 of the pipetting tip holders 34 are suitably sized to allow a pipetting tip 20 to be received inside the pipette tip holder 34. The pipetting tip holders 34 also comprise an at least partially upwardly facing surface 39, which may be at a base of the pipetting tip holder 34, or may be for example a substantially conical wall arrange to conform to a conical form of the pipette tips. The at least partially upwardly facing surface 39 may provide support to the pipette tips 20 but is also arranged to provide vertical support and react to an engagement force applied by the head 100.

The pipetting system comprises at least one carrier engagement feature 40. The carrier engagement feature 40 is arranged to be engaged by the engagement features 412 of the engagement extensions 400, to draw the pipetting head 100 and the carrier 30 toward one another. The carrier engagement features 40 can comprise a longitudinally-facing edge surface, lip or opening, arranged to face in the dispensing direction of the head, or in a direction opposite to the direction in which the openings of the pipette tip holders face, or in a direction opposite to a surface to which the pipette tip carrier is mounted, to enable the pipetting head to be drawn toward the pipette tip holders by the engagement features 412 of the engagement extensions 400. The carrier engagement feature may comprise a recess, a projection, a through hole or an overhang, for example. The carrier engagement feature may be formed in the carrier 30, in a carrier adapter plate 30a for mounting the carrier to a deck 14, or in a deck 14 to which the carrier is to be mounted. The pipette tip carrier 30 illustrated in Figure 4 shows a carrier engagement comprising at least one overhang 40 that projects laterally relative to the pipette tip carrier 30. The overhang 40 may project from any side of the pipette tip carrier 30. The pipette tip carrier 30 may comprise any number of overhangs 40. The overhang(s) may extend along a substantial portion of a length L of the pipette tip carrier 30, or may be arranged to only partially extend along the length L of the pipette tip carrier 30. In other examples, the overhang(s) 40 may extend only partially along the width W of the carrier, or the overhang(s) 40 may extend over a substantial portion of a width W of the pipette tip carrier 30. In the instance that the overhang(s) extends along a substantial portion of the length or width of a side of the carrier 30, the engagement extensions 400 (described further below) can engage with the overhang(s) 40 at different relative positions along the length/width of the carrier 30.

In the example shown in Figure 3, the pipette tip carrier 30 comprises two overhangs 40 in the form of laterally extending ridges that extend from opposite sides of the pipette tip carrier 30. However, the overhangs 40 may comprise any suitable form, such as a protrusion, a laterally extending lip or a laterally extending ridge or combination thereof. In other examples, the overhangs or carrier engagement features 40 may be in the form of discrete tabs, i.e. individual protrusions that extend along a side of the pipette tip carrier 30. The overhangs or carrier engagement features 40 may be solid. The overhangs or carrier engagement features 40 may comprise an aperture (not shown) extending through the carrier or through a wall of the carrier 30. As shown in Figure 4, the overhang(s) extends outwardly i.e. away from a centre of the pipette tip carrier 30. The pipetting head 100 is arranged to engage with the pipette tip carrier 30 via the overhangs 40 to mount the pipette tips 20 into the pipetting head 100 (discussed in more detail below).

The pipetting head 100 comprises a pipetting arrangement 110 that is arranged to retain the array of pipette tips 20 to dispense liquid from the pipette tips 20 in a dispensing direction 5 of the pipetting head 100. The pipette tips 20 are arranged to be loaded into the pipetting head 100 by pushing the pipette tips 20 into the pipetting arrangement 110 in the axial direction (i.e. the Z-direction) with enough force. This is achieved by pressing the pipette tips 20 against an underside of the pipetting head 100. The proximal end 20b of the pipette tips 20 may be configured for connection with the pipetting arrangement 110 of the pipetting head 100. The illustrated pipetting arrangement 110 comprises a substantially solid block with bores provided therein to receive the plunger shafts 232.The pipetting arrangement 110 comprises an array of pipette tip mounts 116. The pipette tip mounts 116 are arranged in a laterally extending array and are configured to hold an array of pipette tips 20 to dispense liquid therethrough.

Each pipette tip mount 116 is therefore arranged for connection to a respective pipette tip 20. The pipette tip mounts 116 may be generally tubular. Each pipette tip mount 116 may be arranged to connect to a proximal end 20b of the pipette tips 20. The pipette tip mounts 116 may be shaped to complement the proximal end 20b of the pipette tips 20. The pipette tips 20 are arranged to be received into respective pipette tip mounts 116 by pushing the pipette tips 20 into the pipette tip mounts 116 with an axial force (in the dispensing direction 5). The pipette tips 20 therefore may be received into respective pipette tip mounts 116 by any suitable mechanical means, such as a push-fit, friction fit, an interference fit or a snap-fit between the pipette tip mount 116 and the pipette tip 20. The pipette tip mounts 116 may further comprise 0-rings, protrusions or arrangements to help mechanically secure the pipette tip 20 in the pipette tip mount 116. Once the pipette tips 20 are received in the pipetting arrangement 110, the distal ends 20a of the pipette tips 20 are oriented in the dispensing direction 5.

The pipetting arrangement 110 is at a distal end of the pipetting head 100 nearest the pipette tip carrier 30. The pipetting mounts 116 therefore are proximal to the pipette tip carrier 30. The pipette tip mounts 116 and the pipetting arrangement 110 separate the dispensing side 150 of the pipetting head 100 and the non-dispensing side 160. As shown in Figure 2, the dispensing side 150 of the pipetting head 100 comprises the pipetting arrangement 110 and the pipette tip mounts 116 and extends away from the pipetting head 100. The non-dispensing side 160 of the pipetting head 100 comprises portions of the pipetting head 100 that are spaced away from the pipette tip mounts 116 and the pipetting arrangement 110 towards the rest of the pipetting head 100.

The pipetting head 100 also comprises an array of plungers 210 that are arranged to dispense liquid via the pipette tips 20 once the pipette tips 20 are engaged with the pipette tip mounts 116. In the illustrated arrangement, the array of plungers 210 are arranged on the non-dispensing side of the pipetting arrangement 110. The array of plungers 210 may correspond in number and/or position with each pipette tip mount 116, so that each plunger 210 may act upon a respective pipette tip mount 216. In certain arrangements, one or more of the plungers may be arranged to provide actuation via a plurality of the pipette tips.

For example, one plunger may be arranged in fluid communication with a plurality of pipette tip mounts 116, such that it may provide pressure changes to a plurality, such as two or four, of the pipette tips when mounted to the pipette tip mounts. A plunger may therefore be provided for a plurality of pipette tip mounts and respective pipette tips. Once the pipette tips 20 are received in the pipette tip mounts 116, the plungers 210 are arranged to actuate along the dispensing direction 5 to provide positive or negative pressure changes to the pipette tips 20 to be able to either drive any fluid contained in the pipette tips 20 out of the distal end 20a of the pipette tip 20 or to draw fluid into pipette tips 20 as required by the relevant aspiration and or dispensing operations of the pipetting head.

The pipetting head 100 comprises a plunger actuation member 200. The plunger actuation member 200 is arranged to actuate the array of plungers 210 to dispense liquid via the pipette tips 20. As shown more clearly in Figure 5, the plunger actuation member 200 comprises a plunger actuation drive mechanism 220 and a plunger actuation body 230. The plunger actuation body 230 functions as a plunger mount. The plunger actuation body 230 is arranged to actuate an array of plunger shafts 232 to dispense liquid through the pipette tips 20 when the pipette tips 20 are mounted in the pipette tip mounts 116. The plunger shafts 232 can actuate plungers disposed in the pipetting arrangement such as in block 110. The plunger shafts can otherwise be connected to plungers disposed in the pipette tips when pipette tips with an integral plunger are used. The plunger actuation body 230 comprises a lower surface 231 that is arranged to abut against the plungers 210 and is preferably connected to the plunger shafts 232 to enable aspiration by drawing the plungers upwards. The lower surface 231 of the plunger actuation body 230 may be substantially flat. The plunger actuation body 230 may extend across the width of the pipetting head 100. In this example, the plunger actuation body 230 comprises a plate. The plunger actuation member 200 is arranged to translate the plunger actuation plate 230 in the dispensing direction 5 (i.e. along the Z-axis) to actuate the plungers 210 to push against the pipetting tips 20.

The pipetting head 100 further comprises a linear guide member in the form of a linear guide rail 170. The linear guide rail 170 is fixed relative to the pipetting head 100. As shown in Figure 5, the linear guide rail 170 extends in the dispensing direction 5. The plunger actuation body 230 is mounted on the linear guide rail 170 so that the plunger actuation body 230 can translate along the linear guide rail 170 in the Z-direction (i.e. in the dispensing direction 5). The plunger actuation body 230 may be slidably mounted onto the guide rail 170 by any suitable slidable mounting means, such as a linear bearing. The linear guide member 170 may extend in a direction substantially perpendicular to a principal plane of the plunger actuation body 230.

The plunger actuation body 230 is slidably mounted to the linear guide member 170 by a plurality of bearing members 182, 184. The location of bearing members 182, 184 can be seen in in Figures 5, the dashed rectangles representing the bearings being behind the bearing support 185 and in side view in Figure 11). The pipetting head 100 comprises a first and second bearing member 182, 184. The bearing members 182, 184 are arranged to translate along the linear guide member 170 in the dispensing direction 5 (i.e. along the Z-axis). The bearing members 182, 184 may be any suitable form of linear bearings to permit linear translation along the linear guide member 170, such as ball bushings, linear bearing units or linear plain bearings.

The first and second bearing members 182, 184 are spaced from one another along the linear guide member 170 in the dispensing direction 5. In this example, the first and second bearing members 182, 184 are spaced away from each other by a distance X. By having the bearing members 182, 184 spaced apart from one another along the linear guide member 170 in the dispensing direction, the plunger actuation member 200 is stabilised against misalignment caused by forces applied out of alignment with the linear guide member 170. The bearing members 180 therefore stabilise the plunger actuation body 230 so that the forces do not tilt the plunger actuation body 230 relative to the plungers 210, which would affect the actuation of the plungers 210. The distance X shown is exemplary and it will be understood that the bearing members 182, 184 may be spaced at any suitable distance from each other. The distance X between the bearing members 182, 184 remains constant as the bearing members 182, 184 translate along the linear guide member 170. While only two exemplary bearing members 182, 184 are shown in this example, the pipetting head 100 may include any number of bearing members 182, 184. It may be preferable to space the bearing members from one another by a suitable proportion of the lateral extent of the plunger actuation body 230, for example. A linear spacing of the bearings of at least a quarter, or at least a half, or at least three quarters, of the lateral extent of the plunger actuation body 230, can be advantageous in stabilising against asymmetrical forces acting on the plunger actuation body 230.

As shown in Figure 5 and Figure 6, the first and second bearing members 182, 184 are securely connected to the bearing support 185, which is secured to the plunger actuation body 230. Therefore, translation of the first and second bearing members 182, 184 along the linear guide member 170, translates the plunger actuation body 230. The bearing support 185 may be substantially perpendicular to the plunger actuation body 230. The bearing support 185 may comprise an irregular shaped body. The bearing support 185 may be securely connected to more than one portion of the plunger actuation body 230 to help stabilise the plunger actuation body 230.

The first bearing member 182 may be arranged near a first end of the bearing support 185, while the second bearing member 184 may be arranged nearer the opposing end of the bearing support 185. The bearing support 185 may comprise one or more axially extending portions 186. One or more of the axially extending portion(s) 186 may be proximal to the pipette tip mounts 116. The first or second bearing member 182, 184 may be secured to the axially extending portion 185 of the bearing support 185. The bearing support 185 may be substantially T-shaped or substantially cross-shaped.

The plunger actuation member 200 is also arranged to translate the plunger actuation body 230 by using a plunger drive mechanism 220. The plunger drive mechanism 220 comprises a linear drive mechanism that is arranged to translate the plunger actuation body 230 in the dispensing direction 5, i.e. in the Z-axis.

The plunger drive mechanism 220 may comprise any suitable drive mechanism that is operable to axially translate the plunger actuation member 230. In the exemplary arrangement, the plunger drive mechanism 220 comprises a threaded ball and screw arrangement 250, as shown in more detail in Figures 6-8.

The threaded ball and screw arrangement 250 comprises a ball nut 252 and a shaft 254. The shaft 254 extends in the dispensing direction 5 and may be fixed relative to the plunger actuation body 230. The shaft 254 may comprise a screw thread on the outer surface of the shaft 254. The screw thread may extend at least partially, or the entire length of the shaft 254. The ball nut 252 is mounted to the shaft 254 and is able to rotate relative to the shaft 254 in the usual manner of a ball nut, to impart linear motion thereto upon rotation of the ball nut relative to the shaft 254. The inner surface of the bore of the ball nut 252 may comprise a complimentary screw thread to match a screw thread on the outer surface of the shaft 254, or a set of ball races to facilitate rotation of the ball nut along the ballscrew thread of the shaft 254. The ball nut 252 is supported by a bearing or bearings 257a, 257b, 257c provided to support the ball nut 252 with respect to the support member 80 while permitting rotation relative to the support member 80 The plunger drive mechanism 220 further comprises a motor 260. As shown, the motor 260 is distal to the pipette tip mounts 116 on the pipetting head 100, to a non-dispensing side of the pipetting head. The motor 260 is fixedly mounted to the pipetting head 100 on a support member 80, which may be a support plate. The motor 260 comprises an output shaft 262, which is coupled to the nut 252 of the ball and screw arrangement 250. As the output shaft of the motor 260 is driven, the nut 252 of the ball and screw arrangement 250 rotates.

Due to the threaded connection between the ball nut 252 and the shaft 254, operation of the motor 260 causes the ball nut 252 to move axially up or down along the shaft 254 in the displacement direction 5, in turn causing the shaft to drive the plunger actuation body 230.

The plunger drive mechanism 220 may further comprise a pulley system 270, shown in greater detail in Figures 7 and 8. The pulley system 270 couples the output shaft 262 of the motor 260 to the nut 252 of the ball and screw arrangement 250. The pulley system 270 couples the motor 260 and the ball and screw arrangement 250 through an arrangement of toothed pulleys 272. In this example, first and second toothed pulleys 274, 276 is provided. As shown, the first pulley 274 is coupled to the output shaft 262 of the motor 260. The output shaft 262 of the motor 260 is connected to an inner bore of the first pulley 274. The teeth of the first pulley 274 are connected to the teeth of the second pulley 276. An inner bore of the second pulley 276 is connected to the nut 252 of the ball and screw arrangement 250. As the motor 260 drives the first gear 272, the second gear 276 is driven, which turns the nut 252. The pulley arrangement 270 also comprises a belt 275 that extends around the outer teeth of the first and second pulleys 272, 274. In the exemplary arrangement, the second pulley 274 has a larger diameter than the first pulley 272 to amplify the torque output of the motor 260. However, the pulley arrangement 270 may comprise or be replaced by any number of gears or pulleys, in any required size and arrangement. In practice any suitable torque transfer arrangement can be employed to transfer torque from the motor to the ballscrew to actuate the plunger actuation body 230 in the dispensing direction, and it may be configured to amplify the torque from the motor 260.

By using such an arrangement, the plunger drive mechanism 220 can displace the plunger actuation body 230 with a large axial force. This arrangement is not only compact and lightweight, but also allows the plungers 210 to effectively and accurately dispense the contents of the pipette tips 20 when mounted to the pipette tips 116.

The pipette tips 20 are arranged to be loaded into the pipetting head 100 by pushing the pipette tips 20 into the pipetting arrangement 110 with the required force. As the plunger drive mechanism 220 generates a large axial force, the plunger drive mechanism 220 may also be used to help load the pipettes 20 arranged in the pipette carrier 30 into the pipetting arrangement 110. The plunger actuation body 230 may therefore be translated towards the pipette tip carrier 30 to load the pipettes 20 into the pipetting arrangement 110, or during a dispensing operation.

The pipetting head 100 further comprises a tip engagement mechanism 300. The tip engagement mechanism 300 is arranged to draw the pipetting head 100 toward the carrier 30 to engage the pipette tips 20 held in the carrier 30 with the pipette tip mounts 116. The tip engagement mechanism comprises a plurality of engagement extensions 400 and an engagement mechanism actuating arrangement 500. The engagement mechanism actuating arrangement 500 is arranged to a non-dispensing 160 side of the pipette tip mounts 116.

The pipette tip mechanism comprises an engagement mechanism actuation member 302 (shown more clearly in Figure 6). The engagement mechanism actuation member 302 is mounted on to the linear guide rail 170 so that the engagement mechanism actuation member 302 can translate along the linear guide rail in the Z-direction (i.e. in the dispensing direction 5). The engagement mechanism actuation member 302 may be mounted onto the guide rail 170 by any suitable means. In this example, the engagement mechanism actuation member 302 is slidably mounted onto the linear guide member 170 by a bearing member 380. The bearing member 380 may be substantially similar to the bearing members 182, 184 and is arranged to translate along the linear guide member 170 in the dispensing direction 5.

The bearing member 380 is securely connected to the engagement mechanism actuation member 302. Therefore, translation of the bearing member 380 along the linear guide member 170 results in translation of the engagement mechanism actuation member 302. The engagement mechanism actuation member 302 is hidden from view in Figure 6 and bearing 380 is therefore visible.

The pipetting head 100 may comprise a plurality of linear guide rails 170.

In the example shown, the pipetting head 100 comprises two linear guide rails 170 that are positioned on opposite sides of the pipette head 100. As shown, both guide rails comprise respective plunger actuation bodies 230 and engagement mechanism actuation members 302. The pipette head 100 may include any number and/or arrangement of linear guide rails 170, plunger actuation bodies 230 and engagement mechanism actuation members 302. One or more support members 306a, 306b, 306c, may be provided to provide further support between the upper support 80 and the pipetting arrangement or plunger block 110, and/or the array of pipette tip mounts 116.

The tip engagement mechanism 300 is arranged to translate the engagement mechanism actuation member 302 by using engagement mechanism actuation arrangement 500. The engagement mechanism actuation arrangement 500 comprises a linear drive mechanism that is arranged to translate the engagement mechanism actuation member 302 in the dispensing direction 5. The engagement mechanism actuation arrangement 500 may comprise any suitable drive mechanism that is operable to translate the engagement mechanism actuation member 302 in the dispensing direction 5. In the exemplary arrangement, the engagement mechanism actuation arrangement 500 comprises a motor 360 and captive ballscrew arrangement 370, as shown in greater detail in Figures 9 and 10.

The captive ball screw arrangement 370 comprises a motor 372, a shaft 374 and a threaded nut contained inside the motor 372 (not shown). As shown, the shaft 374 extends in the dispensing direction 5. The shaft 374 is secured to the pipette tip engagement member 302. The nut (not shown) inside the motor 372 is threadedly engaged with the shaft 374. As the motor 372 rotates, the shaft 374 is arranged to translate in the dispensing direction 5. Rotation of the motor 372 in a first direction causes the shaft 374 to move upwards in the Z-direction away from the pipette tip mounts 116. Rotation of the motor 360 in a second, opposite direction causes the shaft 372 to move downwards in the Z-direction towards the pipette tip mounts 116. The shaft 372 is connected to the pipette tip engagement member 302 so that axial displacement of the shaft 374 results in displacement of the pipette tip engagement member 302 either towards or away from the pipette tip mounts 116. Therefore, the captive ball screw arrangement 370 is arranged to convert rotational output of the motor 370 into axial displacement of the pipette tip engagement member 302 in the dispensing direction 5 (i.e. along the Z-axis). The motor 360 and the captive ball screw arrangement 370 are fixedly mounted in relation to the pipetting head 100. In this example, the motor 370 and the ballscrew (not shown) are mounted on a support member 40. In this example, the support member 40 comprises a plate. The support member 80 is arranged on the non-dispensing side 160 of the pipetting head 100. The arrangement can therefore actuate the engagement mechanism actuation member independently of the plunger actuation member and may actuate the engagement extensions independently of the plunger actuation member to advance or retract them as described herein.

The pipette tip engagement mechanism 300 further comprises a plurality of engagement extensions 400, which are shown in more detail in Figure 2. Each engagement extension 400 is connected to a respective engagement mechanism actuation member 302 and has a proximal end 402 that is connected to the engagement mechanism actuation member 302 and a distal end 404 that extends in the dispensing direction 5 towards the pipette tip mounts 116. The proximal end 402 is connected to the engagement mechanism actuation member 302 by any suitable means, such as bolting or welding, or alternatively, may be formed integrally with the engagement mechanism actuation member 302. The body of the engagement extensions 400 may be elongate. The body of the engagement extensions 400 may comprise substantially planar members. The body of the engagement extension 400 may extend in the dispensing direction 5 of the pipetting head 100 towards the pipette tip mounts 116.

In the illustrated example, the tip engagement mechanism 300 comprises four engagement extensions 400, with two engagement extensions 400 arranged on one side of the pipetting head 100, and two arranged on the opposite side of the pipetting head 100. However, the pipetting head 100 may include any number of engagement extensions 400. Similarly, the engagement extensions 400 may be arranged on the pipetting head 100 in any orientation. For example, the tip engagement mechanism may only include two engagement extensions 400 on opposite sides of the pipetting head 100.

The engagement extensions 400 are connected to the tip engagement mechanism 300. Therefore, translating the tip engagement mechanism 300 in the dispensing direction 5 (i.e. the Z-axis) with the engagement mechanism actuating arrangement 500 also translates the engagement extensions 400. The engagement extensions 400 are therefore also slidably mounted to the linear guide rail 170 via the engagement mechanism actuation member 302.

The engagement extensions 400 are moveable between a first position 400a and a second position 400b. In the first position 400a, as shown in Figure 10, the engagement extensions 400 are arranged to be extendable beyond the array of pipette tip mounts 116 in the dispensing direction 5. In the second position 400b, as shown in Figures 5, 11 and 12, the engagement extensions 400 can be retracted for a dispensing operation. In the retracted position, the engagement extensions 400 are positioned behind the pipette tip mounts 116 in the dispensing direction, i.e. to a non-dispensing side of the pipette tip mounts 116. When the engagement extensions 400 are in the second position 400b, the pipetting actuator can dispense the liquid in the pipettes 20 held in the pipette tip mounts 116 or aspirate fluid into them.

The distal end 404 of the engagement extensions 400 are arranged to be drawn in towards a central plane C of the pipetting arrangement 100. The engagement extensions 400 are therefore flexible or movably mounted such that their distal ends 404 can be moved laterally. As shown in Figure 5, the central plane C extends in a pipetting direction (i.e. the dispensing direction 5) of the pipetting arrangement 100. The central plane C therefore extends perpendicularly to a plane of the array of pipette tip mounts 116. As shown in Figure 10, the distal ends 404 of the engagement extensions 400 are unattached to the pipetting head 100 and so can be deflected inwardly towards the central plane C. When the distal ends 404 of the engagement extensions 400 are actuated by the lateral actuating arrangement 500, the distal ends 404 of the engagement extensions may engage with the pipette tip carrier 30 to help draw the pipette tip carrier 30 towards the pipetting head 100. The distal ends 404 of the engagement extensions 400 comprise engagement features 412 that are arranged to engage with the pipette tip carrier 30. The engagement features 412 may comprise projections that extend laterally away from the engagement extensions 400. The projections 412 may be irregularly shaped. The projections 412 may be domed, planar or hook shaped.

By drawing the projections 412 towards the central plane C, the engagement extensions 400 may engage with the pipette tip carrier 30, a carrier adapter plate 30a or with features provided in the deck 14 for the purpose of being engaged by the engagement features 412. As shown more clearly in Figure 14, the engagement features 412 are arranged to engage with the pipette tip carrier 30 to clamp the pipette tip carrier 30 between opposing engagement extensions 400. In some examples, the engagement features 412 may be received in an opening provided in the pipette tip carrier 30, which may be, for example, a cavity or a through hole. In other examples, the engagement features 412 may abut against the pipette tip carrier 30. The engagement features 412 may abut against an overhang 40, which may be formed in the body of the pipette tip carrier 30. In other examples, the carrier engagement feature, which may be an overhang 40, may be formed in a carrier adapter plate 30a for mounting the carrier 30 to the deck 14, or the overhang 40 may be formed in the deck 14. In each instance, the engagement features 412 may be arranged to engage with the carrier engagement feature or overhang(s) 40. In the example shown in Figure 14, the engagement features 412 are arranged to abut against an underside of the overhang 40 to engage with the pipette tip carrier 30. In other examples, the engagement features 412 may be received in a recess or an aperture (not shown) formed in the overhang 40. In each example, the pipetting head 100 is arranged to "grab", clamp or grasp the pipette tip carrier 30 with the engagement extensions 400.

The pipette tip engagement mechanism 300 and the carrier 30 can advantageously comprise an engagement interface 70 that is configured to be engageable at a plurality of different lateral positions of the carrier 30. The engagement features 412 of the engagement extensions 400 can engage the carrier 30 at a plurality of lateral positions by altering the position of the pipetting head 100 in relation to the carrier 30. In one example, the engagement interface 70 comprises the underside of the overhang 40. The pipette tip engagement mechanism 300 can draw the pipetting head 100 towards the carrier 30 at a plurality of different relative lateral positions of the pipetting head 100 and the carrier 30. The pipette tip engagement mechanism 300 can therefore cause different respective numbers of pipette tip holders 34 to align with respective tip mounts 116. The pipette tip engagement mechanism 300 can engage different numbers of pipette tips 20 in the array of pipette tip mounts 116. In the example shown in Figure 5, the pipette tip engagement mechanism 300 is arranged to align all the pipette tip holders 34 in the pipette tip carrier 30 with a respective pipette tip mount 116. In the example shown in Figure 12B, the pipette head 100 is positioned so that the engagement extensions 400 are only positioned to engage with a proportion of the pipette tip carrier 30, to engage less than a full carrier's-worth of pipette tips. In this arrangement, selected rows and/or columns of pipette tips may be selectively mounted into the pipette tip mounts 116. In figure 12A, the pipetting head is aligned to engage a single column of pipette tips in the pipetting head, which may be achieved with the assistance of the engagement arrangement, but which could in some cases be achieved by the weight of the head and/or the actuators of the apparatus for moving the pipetting head. Greater numbers of pipette tips being engaged required greater force and so with increasing numbers of pipette tips to be engaged, a greater force is required to engage them. So it can be useful to have the system arranged so that the engagement extensions 400 can engage the engagement surface 70 when at least one or two or three or more rows or columns of pipette tips are to be engaged in the pipetting head, for example.

The position of the engagement extensions 400 can therefore be altered along the length L or width W of the carrier 30 by changing the position of the pipetting head 100 relative to the carrier 30. The pipette tip engagement mechanism 300 could further comprise an actuator (not shown) to position the pipetting head 100 relative to the position of the carrier, although this may otherwise be done by a robot or other X, Y Z axis positioning system used to position the pipetting head relative to the deck 14. The engagement extensions 400 can be positioned to "grab" the carrier 30 at any suitable point along the width W and/or the length L of the carrier 30. In this example, the engagement surface 70 is formed, preferably on the underside of the overhang 40, on the pipette tip carrier 40. However, in other examples, the engagement surface 70 may be formed in a carrier adapter plate 30a or may be formed in the deck 14.

The pipetting tip engagement mechanism actuating arrangement 300 may further comprise a lateral actuating arrangement 600. The engagement extensions 400 may be drawn in towards the central plane C by the lateral actuating arrangement 600. The lateral actuating arrangement 600 is arranged to draw the distal ends 404 of the engagement extensions 400 towards the central plane C. The lateral actuating arrangement 600 may comprise any suitable arrangement that is able to provide actuation to the engagement extensions 400 so that the distal ends 404 of the engagement extensions 400 are pushed or pulled towards the central plane C in the X-axis. The lateral actuating arrangement 600 may comprise at least one lateral actuation member 550. The lateral actuation member(s) 555 can be arranged to apply a lateral force to the engagement extensions 400 when the engagement extensions 400 are moved longitudinally (in the dispensing direction 5) along the linear guide rail 170 relative to the plunger actuation body 230. As shown in Figure 9, the lateral actuating members 550 may comprise bearings 555.

The bearings 555 may be rotatably mounted to the pipetting head 100. The bearings 555 may be mounted on the bearing support 185 so that a portion of the bearings 555 is arranged to contact the engagement extensions 400. The bearings 555 are arranged to translate in the dispensing direction 5 (i.e. the Z axis) with the plunger actuation body 230 when the plunger actuation body 230 is translated in the dispensing direction 5. As the plunger actuation body 230 is translated towards the pipette tip carrier 30, the bearings 555 contact against the body 402 of the engagement extensions 400 to exert a lateral force against the engagement extensions 400. This pushes the distal ends 404 of the engagement extensions 400 towards the central plane C. The bearings may be replaced by any suitable laterally projecting member which can apply a lateral force to the engagement extensions 400 to displace them laterally.

In the illustrated example, the number of lateral actuating members 550 corresponds to the number of the engagement extensions 400 on the pipetting head 100. However, in other examples, the pipetting head 100 may comprise any number of lateral actuating members 550. For example, the pipetting head 100 may comprise two lateral actuating members 550 per engagement extension 400 in order to achieve greater deflection of the engagement extensions 400, or conversely, a single lateral actuating member may be arranged to contact a plurality of engagement extensions 400.

In some arrangements, the lateral actuating arrangement 600 may be arranged to selectively draw the engagement extensions 400 in towards the central plane C. In the example shown in Figure 2, the body 402 of the engagement extension 400 may include a cutout 410. The cutout 410 comprises an aperture in the body 402. The cutout 410 may at least partially extend in the dispensing direction 5 of the engagement extension 400. The cutout 410 may be sized to accommodate the lateral actuating member 555 so that as the plunger actuation body 230 is translated in the dispensing direction 5, the lateral actuation member 555 may contact the body 402 of the engagement extensions 400 or the cutout 410.

When the plunger body member 230 and the tip engagement mechanism 300 are spaced from each other in the dispensing direction 5, the lateral actuating member 555 may contact the body of the engagement extensions 400 or may contact or be aligned with the cutouts 410. Therefore, as the plunger body member 230 or the tip engagement mechanism 300 is translated along the dispensing direction 5, the distal end 404 of the engagement extensions 400 may be deflected towards the central plane C or may be in a neutral, non-deflected state. The engagement extensions 400 may therefore be arranged to be drawn towards the central plane C depending on the relative positioning and subsequent translation of the plunger body member and the tip engagement mechanism 300. The movement of the engagement extensions 400 relative to the plunger body member 230 on the linear guide rail 170 causes the engagement extensions 400 to be drawn inwardly towards the central plane C of the pipetting arrangement 110.

The engagement mechanism actuating arrangement 300 may be arranged to actuate a single actuator to actuate the engagement extensions 400. For example, movement of the plunger actuation body 230 may be used to actuate the engagement extensions 400. The engagement mechanism actuating arrangement 300 may be arranged to actuate the engagement extensions 300 by using a plunger actuation member 200. As described above, the pipetting actuation member 200 is also arranged to be actuated to aspirate and/or dispense fluid via the pipette tips 20 in a pipetting operation. In other examples, the engagement mechanism actuating arrangement 300 may further comprise a second actuator 500 configured to retract the engagement extensions 400 back from the dispensing side 150 of the array of pipette tip mounts 116. In this example, the second actuator 500 may comprise the engagement mechanism actuation arrangement 500.

In an exemplary method of operation, the engagement extensions 400 may be in a second position 150b, i.e. retracted away from the pipette tip mounts 116. The lateral actuating member 555 of the lateral actuating mechanism 600 is positioned in the cutout 410 of the engagement extension 400. The plunger body member 230 may remain fixed in position as the engagement mechanism actuation member 302 is translated in the dispensing direction 5 towards the pipette tip mounts 116. This moves the engagement extensions 400 into the first position 150a so that the distal end of the engagement extensions 400 extend beyond the pipette tip mounts 116. As the engagement mechanism actuation member 302 is moved into the first position 150a, the lateral actuating member 555 contacts the body 410 of the engagement extensions 400. This causes the distal end 404 of the engagement extensions 400 to be drawn towards the central plane C as the engagement mechanism actuation member 302 is translated into the first position 150a. After the engagement extensions 400 have been actuated inwardly towards the central plane C, the pipette tip engagement mechanism 300 may also be arranged to draw the engagement extensions towards a plane P of the array of the pipette tip mounts 116 by translating the engagement extensions 400 back towards the pipetting head 100.

In another configuration, the engagement mechanism actuation member 302 may be in the first position 150a. The plunger body member 230 may then be translated away from the pipette tip mounts 116 so that the lateral actuating member 555 contacts the body 410 of the engagement extensions 400. This causes the distal end 404 of the engagement extensions 400 to be drawn towards the central plane C as the plunger body member 230 is moved away from the pipette tip carrier 30. The relative movement of the engagement mechanism actuation member 302 and the plunger body member 230 may be independent and may occur during different operations of the pipetting head 100. For example, the plunger actuation body 230 may translated towards the pipette tip carrier 30 during a dispensing operation, or away from the pipette tip carrier 30 during an aspirating operation. Further, when engaged with the engagement mechanism actuation member and drawn away from the pipetting arrangement, or plunger block, 110, the movement of the plunger actuation body 230 can actuate the tip engagement mechanism 300. Therefore, the plunger actuation body 230 may be used to draw the engagement extensions inwardly to mount the pipette tips 20 into the pipette tip mounts 116. The pipetting head 100 can therefore "grab" the pipette tip carrier 30 and draw the pipette tip carrier 30 towards the pipetting head 100 as the plunger body 230 is drawn away from the dispensing direction in the plunging operation.

As stated above, the actuation of the plunger body 230 creates a large axial force and with this arrangement, it is easier to mount the pipette tips 20 into the pipette tip mounts 116.

A method 1000 of loading a pipetting head 100 is described in Figure 13. At step 1100, a pipetting head 100 is provided. At step 1200, a pipette tip carrier 30 carrying an array of pipette tips is provided below the pipetting head 100. The pipette tip carrier 30 may comprise or be comprised in one or more of a pipette tip box, a tip adapter plate 30a on a deck 14, or a deck 14. At step 1300, the pipetting head 100 is positioned over the pipette tip carrier 30 so that the array of pipette tip mounts 116 are aligned with the array of removable pipettes 34. At step 1400, with the engagement mechanism actuating arrangement 500 actuated to translate the engagement extensions 400 beyond the pipette tip mounts 116, the pipetting head can be advanced toward the array of pipette tips in the pipette tip carrier. Actuation of the plunger actuation body in an upward direction away from the dispensing direction causes the lateral actuating arrangement 600 to actuate the engagement extensions 400 at step 1500, drawing the engagement extensions 400 towards the central plane C of the pipetting head 100. This causes the engagement features 412 of the engagement extensions 400 to engage the pipette tip carrier 30. At step 1600, the engagement extensions 400 are drawn towards a plane P of the array of pipette tip mounts 116 to draw the engagement extensions 400 back to advance the pipette tip head 100 towards the pipette tip carrier 30. This engages the pipette tips 20 with the pipette tip mounts 116. The engagement mechanism actuating arrangement 500 is then advanced to disengage the pipette tip carrier 30 at step 1700. As shown, the distal end 404 of the engagement extensions 400 disengages from the overhangs at step 1700. Optionally, at step 1800, the engagement extensions 400 are drawn backwards towards a plane P of the array of pipette tip mounts 116.

Another exemplary method 2000 of dispensing liquid from the pipette tips 20 is shown in Figure 13. At step 2100, a pipetting head 100 is provided. At step 2200, a pipette tip carrier 30 carrying an array of pipette tips is provided below the pipetting head 100. The pipette tip carrier 30 may be comprised in or comprise one of a pipette tip box, a tip adapter plate 30a on a deck 14, or a deck 14. At step 2300, the pipetting head 100 is positioned over the pipette tip carrier 30 so that the array of pipette tip mounts 116 are aligned with the array of removable pipettes 34. At step 2400, the array of pipette tips 20 in the pipetting tip mounts 116 are engaged by moving the plunger actuation member 200 along the linear guide member 170. At step 2500, the plunger actuation member 200 is moved along the linear guide member 170 in the dispensing direction 5 so as to dispense liquid via the pipette tips 20. Once the contents of the pipette tips 20 have been dispensed, the pipetting head 100 may be arranged to remove the pipette tips 20 from the plunger mounts 116, which may be done by over-extension of plunger shafts 232 to push the pipette tips out of the pipette tip mounts 166.

Other advantageous arrangement based upon the present disclosure can be achieved as defined in the following clauses: Clauses: 1. A pipetting system comprising a pipetting head for a liquid dispensing apparatus and a carrier; the pipetting head comprising: an array of pipette tip mounts arranged in a laterally extending array and configured to hold an array of pipette tips to dispense liquid therethrough; and a pipette tip engagement mechanism, arranged to draw the pipetting head toward the carrier to engage pipette tips held in the carrier in the pipette tip mounts; the carrier comprising a laterally extending array of pipette tip holders arranged to receive pipette tips for engagement with the pipetting head; wherein the pipette tip engagement mechanism and the carrier comprise an engagement interface configured to be engageable at a plurality of different relative lateral positions of the pipetting head and the carrier, such that the pipette tip engagement mechanism can draw the pipetting head towards the carrier at the plurality of different relative lateral positions, to cause different respective numbers of pipette tip holders to align with respective tip mounts, for engaging different numbers of pipette tips in the array of pipette tip mounts.

2. The pipetting system according to clause 1, wherein the pipetting head further comprises a plurality of engagement extensions connected to the pipette tip engagement mechanism, wherein the engagement extensions comprise engagement features arranged for engaging the carrier, wherein the engagement extensions are positionable at different relative positions along a length of the carrier.

3. The pipetting system according to clause 2, wherein the engagement features comprise projections that project laterally from the engagement extensions.

4. The pipetting system according to clause 3, wherein the projections project inwardly towards a central plane of the pipetting head, the central plane extending perpendicularly to the array of pipette tip mounts.

5. The pipetting system according to any one of clauses 2 to 4, comprising at least one carrier engagement feature, comprising a longitudinally-facing edge or surface, arranged to be engaged by the engagement features of the engagement extensions, to draw the pipetting head and the carrier toward one another, the carrier engagement feature preferably being formed in the carrier, in a carrier adapter plate for mounting the carrier to a deck, or in a deck to which the carrier is to be mounted for the pipetting operation.

6. The pipetting system according to clause 5, wherein the or each carrier engagement feature extends substantially laterally along a portion of a length of a side of the carrier so that the engagement extensions can engage the carrier engagement feature at different relative positions along the length of the carrier.

7. The pipetting system according to any preceding clause, wherein the pipette tip engagement mechanism comprises an actuator to position the pipetting head relative to the position of the carrier.

8. The pipetting system according to any one of clauses 2 to 7, wherein the pipette tip engagement mechanism is arranged to actuate the engagement extensions to draw them inwardly toward a central plane of the pipetting head extending in a pipetting direction of the pipetting head so as to engage the carrier.

9. The pipetting system according to clause 8, wherein the pipette tip engagement mechanism is arranged to actuate the engagement extensions to draw them toward the plane of the array of pipette tip mounts after actuating them inwardly toward a central plane of the pipetting arrangement extending in a pipetting direction of the pipetting arrangement.

10. The pipetting system according to any preceding clause, wherein the carrier engagement feature is formed in one of: a pipette tip carrier, a pipette tip box, a tip adapter plate or a deck.

11. A pipette tip carrier, a pipette tip box, a tip adapter plate or a deck, for the system of any of clauses 1 to 10, comprising a carrier engagement feature comprising a recess, edge, lip or opening, providing an engageable edge facing in the dispensing direction, so as to be engageable by a hook provided on a pipette tip engagement mechanism of the pipetting head, to draw the pipetting head toward the carrier.

A. A pipetting head for a liquid dispensing apparatus, for use with an array of pipette tips, the pipetting head comprising: a pipetting arrangement comprising an array of pipette tip mounts arranged to retain the array of pipette tips to dispense liquid from the pipette tips in a dispensing direction of the pipetting head; a plunger actuation member arranged to actuate an array of plungers to dispense liquid via pipette tips when engaged with the pipette tip mounts; at least one linear guide member extending in the dispensing direction of the pipetting head; the plunger actuation member being slidably mounted to the at least one linear guide member via a plurality of bearing members, the bearing members being spaced from one another along the linear guide members in the dispensing direction.

B. The pipetting head according to clause A, wherein the plunger actuation member is stabilised against misalignment caused by forces applied out of alignment with the linear guide member by the bearing members being spaced from one another along the linear guide member in the dispensing direction.

C. The pipetting head according to any preceding clause wherein the plunger actuation member is arranged to be able to actuate a pipette tip engagement mechanism, wherein the pipette tip engagement mechanism is arranged for drawing the pipetting head toward a pipette tip carrier to engage an array of pipette tips with the array of pipette tip mounts.

D. The pipetting head according to any preceding clause, further comprising an engagement mechanism having an engagement mechanism actuation member and a plurality of engagement extensions arranged to be extendable beyond the array of pipette tip mounts in a dispensing direction, the engagement actuation member being slidably mounted to the at least one guide member.

E. The pipetting head according to any preceding clause, further comprising an engagement mechanism having an engagement mechanism actuation member and a plurality of engagement extensions arranged to be extendable beyond the array of pipette tip mounts in a dispensing direction, the engagement actuation member being slidably mounted to the at least one guide member.

F. The pipetting head according to any preceding clause, further comprising an engagement mechanism actuating arrangement arranged to a non-dispensing side of the array of pipette tip mounts.

G. The pipetting head according to clause F, further comprising a plurality of engagement extensions connected to the engagement mechanism actuation arrangement, comprising engagement features arranged for engaging a pipette tip carrier, and being moveable between: a first position in which the engagement extensions extend beyond the array of pipette tip mounts in the dispensing direction; and a second position in which the engagement extensions are retracted for a dispensing operation.

H. A method of operating a pipetting head for a liquid apparatus, the method comprising: providing a pipetting head according to clause A, providing a pipette tip carrier carrying an array of pipette tips below the pipetting head; positioning the pipetting head over the pipette tip carrier such that the array of pipette tip mounts is aligned with the array of removable pipettes; engaging the array of pipette tips in the pipetting tip mounts by movement of the plunger actuation member along the linear guide member; and sliding the plunger actuation member along the linear guide member in the dispensing direction so as to dispense liquid via the pipette tips.

Although the invention has been described above with reference to one or more preferred embodiments, it will be appreciated that various changes or modifications may be made without departing from the scope of the invention as defined in the appended claims.

Claims

CLAIMS1. A pipetting head for a liquid dispensing apparatus, for use with an array of pipette tips, the pipetting head comprising: a pipetting arrangement comprising an array of pipette tip mounts, wherein the pipetting arrangement is arranged to retain the array of pipette tips to dispense liquid from the tips in a dispensing direction of the pipetting head; a tip engagement mechanism comprising: an engagement mechanism actuating arrangement arranged to a non-dispensing side of the pipette tip mounts; and a plurality of engagement extensions connected to the engagement mechanism actuating arrangement, comprising engagement features arranged for engaging a pipette tip carrier to draw the pipetting head toward the pipette tip carrier, and being moveable between: a first position in which the engagement extensions extend beyond the array of pipette tip mounts in the dispensing direction and a second position in which the engagement extensions are retracted for a dispensing operation.
2. The pipetting head according to claim 1, wherein the engagement features comprise projections that extend laterally from the engagement extensions.
3. The pipetting head according to claim 2, wherein the projections extend inwardly toward a central plane of the pipetting arrangement, the central plane extending in the pipetting direction of the pipetting arrangement.
4. The pipetting head according to any preceding claim, wherein the engagement mechanism actuating arrangement is arranged to actuate the engagement extensions to move them laterally, into an engaged configuration.
5. The pipetting head according to claim 4, wherein the engagement mechanism actuating arrangement is arranged to actuate the engagement extensions to move them inwardly toward a central plane of the pipetting arrangement, the central plane extending in the pipetting direction of the pipetting arrangement.
6. The pipetting head according to claim 4 or claim 5, wherein the engagement mechanism actuating arrangement is arranged to actuate the engagement extensions to draw them toward the plane of the array of pipette tip mounts after actuating them laterally, or inwardly toward a central plane of the pipetting arrangement.
7. The pipetting head according to any of claims 4 to 6, wherein the engagement mechanism actuating arrangement is arranged to actuate a single actuator to actuate the engagement extensions.
8. The pipetting head according to any of claims 4 to 7, wherein the engagement mechanism actuating arrangement is configured to actuate the engagement extensions using a pipetting actuator, wherein the pipetting actuator is also arranged to be actuated to dispense fluid through the pipette tips in a pipetting operation.
9. The pipetting head according to claim 7 or 8, wherein the engagement mechanism actuating arrangement further comprises a second actuator configured to retract the engagement extensions back from the dispensing side of the array of pipette tip mounts.
10. The pipetting head according to any preceding claim, wherein the pipetting head further comprises at least one linear guide member oriented in the dispensing direction, wherein the engagement extensions are mounted to slide along the linear guide member to move between the first and second positions.
11. The pipetting head according to claim 10, wherein the pipetting head further comprises a plunger mount arranged to actuate an array of plunger shafts to dispense liquid through the pipette tips when the pipette tips are mounted to the pipette tip mounts, wherein the plunger mount is arranged to slide on the linear track.
12. The pipetting head according to claim 11, wherein the movement of the engagement extensions relative to the plunger mount on the linear guide member causes the engagement extensions to be drawn inwardly towards a central plane of the pipetting arrangement, the central plane extending in the pipetting direction of the pipetting arrangement.
13. The pipetting head according claim 12, wherein the engagement mechanism actuation arrangement comprises at least one lateral actuation member, wherein the lateral actuation member is arranged to apply a lateral force to the engagement extensions when the engagement extensions are moved longitudinally along the guide rail relative to the plunger mount.
14. The pipetting head according to any preceding claim, wherein the engagement extensions comprise substantially planar members extending in a dispensing direction of the pipetting head.
15. A method of engaging a pipetting head for a liquid dispensing apparatus with an array of pipette tips, the method comprising: providing a pipetting head according to claim 1; providing a pipette tip carrier carrying an array of pipette tips below the pipetting head; positioning the pipetting head over the pipette tip carrier such that the array of pipette tip mounts is aligned with the array of removable pipettes; actuating the engagement mechanism actuating arrangement to translate the engagement extensions beyond the pipette tip mounts; engaging the engagement features of the engagement extensions with the pipette tip carrier; and actuating the engagement mechanism actuating arrangement to draw the engagement extensions back towards the pipette tip mounts to advance the pipetting head towards the pipette tip carrier.
16. A pipette tip carrier for use with the pipetting head of any of claims 1 to 14, comprising: a laterally extending array of pipette tip holders, arranged in a laterally extending plane of the pipette tip carrier, and arranged to receive pipette tips; the pipette tip holders comprising reaction points or surfaces which are oriented at least partially in a reaction direction which is perpendicular to the lateral plane, for reacting a tip engagement force that acts perpendicularly to the laterally extending plane when the pipette tips are pressed into a pipetting head carrier; and at least one engagement feature, comprising a recess, edge, lip or opening, providing an engageable edge facing in a direction opposite to the reaction direction, for engagement by an engagement feature provided on a pipette tip engagement mechanism of the pipetting head, to draw the pipetting head toward the carrier.
17. A pipette tip carrier according to claim 15, wherein the pipette tip carrier is a pipette tip box.
18. A pipette tip carrier adapter plate, arranged for mounting to a deck of a pipetting system to secure a pipette tip carrier in relation to the deck, the adapter plate comprising: attachment features for attaching the adapter plate to the deck; a pipette tip carrier receiving surface extending in a lateral plane and comprising securing features for receiving the pipette tip carrier and securing the pipette tip carrier against movement in at least a lateral direction with respect to the deck; and at least one engagement feature, comprising a recess, edge, lip or opening, providing an engageable edge facing in a direction opposite to the carrier receiving surface, for engagement by a lateral projection provided on a pipette tip engagement mechanism of a pipetting head, to draw the pipetting head toward the carrier when mounted to the adapter plate.
19. A deck of a pipetting system comprising a pipetting head configured for use with detachable pipette tips, the deck comprising: a carrier receiving surface comprising attachment features for attaching a pipette tip carrier to the deck and securing the pipette tip carrier against movement in at least a lateral direction with respect to the deck; and at least one engagement feature, comprising a recess, edge, lip or opening, providing an engageable edge facing in a direction opposite to the carrier receiving surface, for engagement by a lateral projection provided on a pipette tip engagement mechanism of a pipetting head, to draw the pipetting head toward the carrier when mounted to the adapter plate.