Pipetting head for a liquid dispensing apparatus

Abstract

A pipette tip is provided for a liquid dispensing apparatus. The pipette tip has a pipette tip clamping mechanism and a plunger clamping mechanism. The pipette tip clamping mechanism and the plunger clamping mechanism each include a mounting plate having a plurality of mounts, a clamping plate having a plurality of clamping members, and a drive mechanism. Each clamping member is associated with one of the mounts. The drive mechanism includes an actuator operable to drive relative movement between the clamping plate and the mounting plate in an axial direction to selectively engage the clamping mechanism. The pipette tip also includes a drive actuator operable to move the plunger clamping mechanism toward or away from the plate of the pipette tip clamping mechanism in the axial direction to draw or dispense liquid during use. The drive actuator is configured to operate independently of the pipette tip clamping drive mechanism and the plunger clamping drive mechanism.

Description

Technical Field

[0001] This invention relates to a pipette head for a liquid dispensing device, and more particularly to a pipette head having a pipette tip clamping mechanism and a plunger clamping mechanism, wherein a pipette having a pipette tip and a plunger can be securely mounted to the pipette head. Background Technology

[0002] It is known that pipettes can be used to aspirate or dispense liquid samples.

[0003] It is also known that pipettes used in the prior art have a plunger arranged in the pipette tip. A typical pipette, referred to as a "positive displacement" pipette, uses a plunger or piston to aspirate or dispense liquid by direct contact with the sample liquid or through a small air gap. During use, the pipette tip and plunger are mounted on the pipette head of a liquid dispensing device, with the pipette head driving the plunger relative to the tip to aspirate or dispense liquid from an orifice at the distal end of the pipette tip. Such pipettes can be used in automated machines to improve the accuracy and repeatability of pipetting actions.

[0004] The inventors have discovered several problems with the way pipettes are connected to known pipette tips used in liquid dispensing devices.

[0005] Therefore, an improved pipette tip is needed. Summary of the Invention

[0006] A first aspect of the invention provides a pipette head for use with a liquid dispensing apparatus, the pipette head being used with a pipette array, each pipette having a pipette tip and a plunger disposed within the pipette tip. The pipette head includes: a pipette tip clamping mechanism for connecting and clamping the pipette tips of the pipette array during use; and a plunger clamping mechanism for connecting and clamping the plunger of the pipette array during use. The pipette tip clamping mechanism includes: a pipette tip mounting plate having a plurality of pipette tip mounting members, each configured to connect with one of the pipette tips during use; a pipette tip clamping plate having a plurality of pipette tip clamping members, each associated with one of the plurality of pipette tip mounting members; and a pipette tip clamping drive mechanism including an operable actuator to drive relative movement between the pipette tip clamping plate and the pipette tip mounting plate in an axial direction, thereby selectively engaging the pipette tip clamping mechanism by moving it between a clamped position and a released position. The plunger clamping mechanism includes: a plunger mounting plate having a plurality of plunger mounting members, each plunger mounting member configured to connect with one of the plungers during use; a plunger clamping plate having a plurality of plunger clamping members, each plunger clamping member associated with one of the plurality of plunger mounting members; and a plunger clamping drive mechanism including an operable actuator to drive relative movement between the plunger clamping plate and the plunger mounting plate in the axial direction, thereby selectively engaging the plunger clamping mechanism by moving it between a clamping position and a release position. The pipette tip further includes a drive actuator operable to move the plunger clamping mechanism toward or away from the plate of the pipette tip clamping mechanism in the axial direction to aspirate or dispense liquid during use, the drive actuator being configured to operate independently of the pipette tip clamping drive mechanism and the plunger clamping drive mechanism.

[0007] This provides an extremely compact arrangement that allows a large number of pipettes to be precisely and securely mounted to the pipette tip. This is particularly advantageous for liquid dispensing devices used with standard 384-well plates, as the compact arrangement allows for 384 mounting collars and locking members to hold 384 pipettes in a 16×24 matrix. This enables the aspiration of liquid from or dispensing of liquid into a conventional 384-well plate in a single operation. As used herein, the terms “clamp” and “gripper” refer to an arrangement in which pipette tips or plungers, or both, are mounted and locked in place to prevent accidental removal. This contrasts with arrangements where pipette tips or plungers are not locked in place (e.g., using interference fits or snap-fit ​​connections), where the pipette tips or plungers can be easily removed by axial pulling. The clamping arrangement also improves the accuracy of aspiration and dispensing operations by preventing small relative movements that may occur between the pipette tip and the plunger or pipette tip.

[0008] Furthermore, by providing independently operated drive actuators for dispensing or aspiration operations, a wider variety of plunger speeds can be achieved, enabling the pipette tip to operate precisely in both contact and non-contact dispensing modes. This contrasts with some known liquid handling devices where the pipette tip and plunger are connected to a plate positioned along a common set of screws and can only move relatively slowly relative to each other along these common screws.

[0009] Using independently operated drive actuators, the plunger clamping mechanism, and therefore any plunger mounted on it, can move relative to the pipette tip clamping mechanism to perform aspiration and dispensing operations independently of the mechanisms operating the pipette tip holder and plunger holder. For dispensing injections, the plunger travel distance can be very small, for example, within 1 mm or less. Therefore, a high level of acceleration / deceleration is required to achieve the target speed for non-contact dispensing. The independently operated drive actuators can be configured to accelerate and decelerate the plunger clamping mechanism at sufficiently high speeds, making it possible to perform both non-contact and contact dispensing using the same mechanism.

[0010] The term "independent operation" refers to an arrangement where the drive actuator includes a separate drive mechanism from the pipette tip clamping drive mechanism and the plunger clamping drive mechanism. This allows the drive mechanism to be set according to the acceleration and deceleration characteristics required for dispensing and aspiration operations, rather than according to the required clamping characteristics, or a trade-off between these characteristics. This contrasts directly with arrangements where the pipette tip and plunger are mounted on a plate arranged along a common screw. In these arrangements, all drive mechanisms (including the drive mechanism of the actuator controlling the dispensing operation) must operate with the same pitch. These arrangements may also require synchronized plate movement to perform the dispensing operation. This necessitates more complex control to ensure accurate dispensing and prevent clogging.

[0011] The drive actuator can be an indirect drive actuator, such as a belt or chain driven by a motor, through which the plunger clamping mechanism moves relative to the pipette tip clamping mechanism. Preferably, the drive actuator is a direct drive actuator. As used herein, the term "direct drive actuator" refers to a drive mechanism including a motor that is either directly connected to the plunger clamping mechanism or connected to the plunger clamping mechanism in a rotationally rigid manner. Throughout this specification, the term "direct drive actuator" is used to refer to arrangements of direct connection and arrangements of the motor being connected to the plunger clamping mechanism via a rotationally rigid connection. The use of a direct drive actuator minimizes the rotational backlash between the plunger clamping mechanism and the motor. This allows the movement of the plunger clamping mechanism to start and stop quickly and accurately. This contrasts with indirect drive mechanisms, in which the motor is connected to the plunger via one or more belts or chains.

[0012] The drive actuator may be a ball screw actuator, which includes a ball screw and a motor fixed relative to the chassis of the pipette tip. The motor is connected to the plunger clamping mechanism via the ball screw to drive the plunger clamping mechanism to move axially relative to the chassis and the pipette tip clamping mechanism.

[0013] It has been found that, for example, direct drive arrangements via ball screws provide a higher level of heavy-load acceleration / deceleration than belt-driven systems, enabling non-contact dispensing of low-volume liquid samples. Furthermore, direct drive arrangements offer greater positional accuracy and repeatability compared to equivalent belt-driven mechanisms. This has a significant impact on dispensing performance.

[0014] The plunger clamping drive mechanism preferably includes a plurality of guide rods, through which the plunger clamping plate is connected to the plunger mounting plate, and the plunger clamping plate and the plunger mounting plate are movable relative to each other in the axial direction along the guide rods by an actuator of the plunger clamping mechanism. The plurality of guide rods preferably move in the axial direction together with the plunger clamping plate and the plunger mounting plate toward and away from the plate of the pipette tip clamping mechanism by the drive actuator. This helps to keep the plates parallel. For example, the plurality of guide rods may include four guide rods located at the four corners of the plunger clamping plate and the plunger mounting plate. In other embodiments, the plunger clamping drive mechanism may include a plurality of actuators located at different positions on the periphery of the plunger clamping mechanism, these actuators being configured to operate together.

[0015] The plunger clamping drive mechanism can include any suitable mechanism for driving relative movement between the plunger clamping plate and the plunger mounting plate in the axial direction when the actuator of the plunger clamping drive mechanism is operated. For example, the plunger clamping drive mechanism can include a threaded shaft connected to the actuator of the plunger clamping drive mechanism, the threaded shaft extending through a fixed threaded hole relative to one of the plunger mounting plate and the plunger clamping plate, such that the threaded shaft drives relative movement between the plunger clamping plate and the plunger mounting plate in the axial direction when rotated by the actuator. The threaded output shaft of the plunger clamping drive mechanism can move axially independently of the pipette tip clamping mechanism.

[0016] The entire plunger clamping drive mechanism, together with the plunger clamping plate and the plunger mounting plate, can move axially toward and away from the plate of the pipette tip clamping mechanism via a drive actuator.

[0017] The pipette tip clamping drive mechanism may include a threaded shaft of an actuator connected to the pipette tip clamping drive mechanism. This threaded shaft extends through a fixed threaded hole relative to one of the pipette tip mounting plate and the pipette tip clamping plate, such that the threaded output shaft drives relative movement between the pipette tip clamping plate and the pipette tip mounting plate in the axial direction when rotated by the actuator. The threaded output shaft of the pipette tip clamping drive mechanism can move axially independently of the plunger clamping mechanism.

[0018] The pipette tip clamping plate is preferably located below the pipette tip mounting plate. The pipette tip clamping plate may be the lowest plate in the pipette tip assembly. As used herein, the terms "low," "below," and "lowest" refer to the normal orientation of the pipette tip during use.

[0019] The plurality of pipette tip clamping components may include multiple sleeves defining clamping areas. The plurality of pipette tip clamping components may be coaxial with the plurality of pipette tip mounting pieces. When the pipette tip clamping mechanism is engaged, the plurality of pipette tip clamping components may be externally connected to the plurality of pipette tip mounting pieces.

[0020] The plurality of sleeves may be defined by one or more discrete components fixed to the pipette tip clamping plate. In some preferred embodiments, the plurality of sleeves are defined by holes in the pipette tip clamping plate itself.

[0021] Each of the plurality of pipette tip mounts may include a radially extending feature on its outer surface, the radially extending feature being configured to form half of a snap-fit ​​connection. When the pipette tip clamping mechanism is in the clamped position, the clamping area of ​​each of the plurality of sleeves may be axially adjacent to the radially extending feature on the outer surface of the associated pipette tip mount. When the pipette tip clamping mechanism is in the released position, the clamping area of ​​each of the plurality of sleeves may be axially offset from the radially extending feature on the outer surface of the associated pipette tip mount.

[0022] The plurality of plunger mounting components may include a plurality of axially extending sleeves. The plurality of plunger clamping components may include a plurality of axially extending clamping rods that extend within the plurality of axially extending sleeves when the plunger clamping mechanism is in the clamping position.

[0023] Each of the plurality of axially extending sleeves may include a radially extending feature on its inner surface, the radially extending feature being configured to form half of a snap-fit ​​connection. When the plunger clamping mechanism is in the clamping position, the clamping area of ​​each of the plurality of clamping rods may be axially adjacent to the radially extending feature on the inner surface of the plunger mount associated therewith, and when the plunger clamping mechanism is in the release position, the clamping area of ​​each of the plurality of clamping rods is axially offset from the radially extending feature on the inner surface of the plunger mount associated therewith.

[0024] The pipette head may further include at least one pipette tube. The at least one pipette tube includes: a pipette tip having a distal end with a dispensing orifice and a proximal end with a tip connector component for connecting the pipette tip to the pipette head during use; and a plunger having a distal end located inside the pipette tip and a proximal end with a hollow plunger connector component for connecting the plunger to the pipette head during use. The tip connector component has a radially extending feature on its inner surface, the radially extending feature being configured to form a snap-fit ​​connection with a radially extending feature on the outer surface of one of the plurality of pipette tip mounts, and configured to resiliently deflect radially outward from a rest position to an extended position, in the rest position having a first outer diameter, and in the extended position having a second outer diameter, the second outer diameter being larger than the first outer diameter by at least the radial extent of the radially extending feature of the tip connector component. Furthermore, the clamping area of ​​each of the plurality of sleeves in the suction head clamping mechanism has an inner diameter that is greater than or equal to the first outer diameter of the suction head connector component and less than the second outer diameter of the suction head connector component, such that the clamping area prevents the suction head connector component from deflecting to the extended position, thereby releasing the snap-fit ​​connection when the suction head clamping mechanism is in the clamping position.

[0025] The pipette head may further include at least one pipette tube. The at least one pipette tube includes: a pipette tip having a distal end with a dispensing orifice and a proximal end with a tip connector assembly for connecting the pipette tip to the pipette head during use; and a plunger having a distal end located inside the pipette tip and a proximal end with a hollow plunger connector assembly for connecting the plunger to the pipette head during use. The plunger connector component has a radially extending feature on its outer surface, the radially extending feature being configured to form a snap-fit ​​connection with a radially extending feature on the inner surface of one of the plurality of plunger mounts, and configured to resiliently deflect radially inward from a rest position to a compressed position, wherein the plunger connector component has a first inner diameter in the rest position and a second inner diameter in the compressed position, the second inner diameter being smaller than the first inner diameter and at least smaller than the radial extent of the radially extending feature of the plunger connector component, and wherein each of the plurality of axially extending clamping rods has a clamping region having an outer diameter less than or equal to the first inner diameter of the plunger connector component and greater than the second inner diameter of the plunger connector component, such that the clamping region prevents the plunger connector component from deflecting to the compressed position, thereby releasing the snap-fit ​​connection when the plunger clamping mechanism is in the clamping position.

[0026] According to a second aspect of the present invention, a liquid dispensing device is provided, comprising: a body having a microplate receiving region; and a pipette according to the first aspect, the pipette being positioned above the microplate receiving region. Attached Figure Description

[0027] Further features and advantages of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0028] Figure 1 This is a perspective view of a liquid dispensing device with a pipette tip according to the present invention;

[0029] Figure 2 This is a perspective view of the pipette according to the present invention;

[0030] Figure 3 yes Figure 2 Side view of the pipette tip;

[0031] Figure 4 yes Figure 2 A perspective view of a pipette tip, in which various components are omitted for clarity, and the pipette tip clamping mechanism and plunger clamping mechanism are shown.

[0032] Figure 5 Is it through Figure 4 A cross-sectional view showing the plate of the pipette tip clamping mechanism and the plate of the plunger clamping mechanism;

[0033] Figure 6 Is it through Figure 4 An enlarged cross-sectional perspective view showing the plate of the pipette tip clamping mechanism;

[0034] Figure 7 yes Figure 2 An enlarged sectional view of the plate of the pipette tip clamping mechanism of the pipette tip, showing the pipette tip mounting sleeve;

[0035] Figure 8 yes Figure 2 An enlarged cross-sectional perspective view of the pipette head, in which various components are omitted for clarity, and the plate of the plunger clamping mechanism is shown in more detail;

[0036] Figure 9 yes Figure 2 An enlarged sectional view of the plate of the plunger clamping mechanism of the pipette head, showing the plunger mount and clamping member;

[0037] Figure 10 yes Figure 2 A perspective view of the plunger clamping mechanism of a pipette tip, wherein the plunger mounting plate is omitted for clarity, and the plunger clamping plate is shown in the clamped position;

[0038] Figure 11 yes Figure 2 A perspective view of the plunger clamping mechanism of a pipette tip, wherein the plunger mounting plate is omitted for clarity, and the plunger clamping plate is shown in the released position;

[0039] Figure 12 yes Figure 2 Front view of the cross-section of the pipette tip;

[0040] Figure 13 yes Figure 2 A cross-sectional side view of the pipette tip;

[0041] Figure 14 Is with Figure 1 A cross-sectional view of a pipette used in a liquid dispensing system;

[0042] Figure 15 yes Figure 14 A perspective view of the pipette tip and plunger of a pipette, with the plunger removed from the pipette tip;

[0043] Figure 16 yes Figure 14 An enlarged cross-sectional view of the pipette shows the tip connector assembly and plunger connector assembly in more detail;

[0044] Figure 17 yes Figure 14 A perspective view of a pipette, showing the pipette tip clamping mechanism, the tip mount, and the associated tip holder; and

[0045] Figures 18 to 22 This is an enlarged sectional view of a portion of the pipette tip clamping mechanism and plunger clamping mechanism during the various stages of pipette connection. Detailed Implementation

[0046] Figure 1 A liquid dispensing device 10 for use with a positive displacement pipette array 1010 is shown. The device 10 includes a body 12 and a pipette head 100. The body 12 has a microplate receiving area or platform 14, and the pipette head 100 is positioned above the microplate receiving area 14. The microplate receiving area 14 has an upper surface 16 arranged at a substantially horizontal level to receive laboratory microplates. The receiving area 14 may be situated on a height-adjustable support structure 18, which allows the height of the microplate receiving area 14 to be varied as needed. The receiving area 14 can be configured to hold laboratory microplates in a fixed position. For example, the upper surface 16 of the receiving area 14 may include one or more recesses (not shown) arranged to receive the microplates and prevent lateral translation of the microplates relative to the receiving area 14. The device 10 will typically be used in… Figure 1 Used in the direction shown to hold the product within the pores of the microplate by gravity. Therefore, Figure 1 The axis marked Z represents the upward direction, while gravity acts in the opposite direction to hold the product within the pores of the microplate. Therefore, references to upward and downward directions, or axial directions, refer to the direction along... Figure 1 The movement along the Z-axis refers to the lateral or transverse direction. Figure 1 The movement is marked in the X and Y directions. Therefore, the vertical direction or height also refers to the direction along... Figure 1 The dimension or movement of the Z-axis. The pipette head 100 is configured as a fixed pipette array (as described below). Figures 2 to 9 (As discussed), and can be moved relative to platform 14 to bring the pipette mounted on pipette 100 close to the microplate supported on platform 14, thereby allowing liquid to be drawn from or dispensed into the microplate pores.

[0047] Figures 2 to 4The pipette head 100 is shown in more detail. The pipette head includes a head base 101 having an upper head base component 102 and a lower head base component 103, which are bolted together to form the body of the pipette head 100. The upper and lower head base components are connected to the body of the device via a chassis support plate 104. The chassis support plate 104 preferably allows the entire pipette head 100 to be moved in a conventional manner relative to the receiving area of ​​the device in the X, Y, and Z directions using one or more head actuators (not shown). The pipette head 100 also includes a pipette tip clamping mechanism 120 and a plunger clamping mechanism 140. The pipette tip clamping mechanism 120 is used to connect or couple to and clamp the pipette tips of the positive displacement pipette tip array during use, and the plunger clamping mechanism 140 is used to connect or couple to and clamp the plunger of the positive displacement pipette array during use. A direct drive actuator 160, mounted on the upper head chassis assembly 102, is operably moved axially toward or away from the plate of the pipette tip clamping mechanism to aspirate or dispense liquid during use. The direct drive actuator 160 is fixed relative to the head chassis 101 and extends between the head chassis 101 and the plunger clamping mechanism 140.

[0048] The pipette tip clamping mechanism 120 includes a pipette tip mounting plate 121, a pipette tip clamping plate 125 located below the pipette tip mounting plate 121, and a pipette tip clamping drive mechanism 130 operable to drive relative movement between the pipette tip mounting plate 121 and the pipette tip clamping plate 125. In this example, the pipette tip mounting plate 121 is configured as part of the lower head chassis component, and the pipette tip clamping drive mechanism 130 is configured to move the pipette tip clamping plate 125 toward and away from the fixed pipette tip mounting plate 121 to selectively engage the pipette tip clamping mechanism 120.

[0049] like Figures 5 to 7As best shown, the pipette tip mounting plate 121 has an array of holes 122 extending axially through the thickness of the pipette tip mounting plate 121. Securing within each hole 122 is a pipette tip mount 123, extending axially downward from the plate 121 and configured to connect with one of the pipette tips during use. Each pipette tip mount 123 is in the form of a tubular tip mounting sleeve held in one of the array of holes 122. In this example, each hole 122 has a diameter smaller than the outer diameter of the tip mounting sleeve 123. These limitations prevent the tip mounting sleeve 123 from being forced through the tip mounting plate in an upward direction when the tip mounting sleeve is initially inserted into the pipette tip. The upper end of the tip mounting sleeve 123 preferably includes an inwardly tapered end face to facilitate the insertion of components of the plunger clamping mechanism through the hole in the tip mounting sleeve 123. The lower end of the pipette tip mounting sleeve 123 preferably has an outwardly tapering end face to facilitate insertion of the lower end of the pipette tip. The outer surface of each pipette tip mounting sleeve 123 includes a radially extending feature configured to form a snap-fit ​​connection with a correspondingly shaped feature on the inner surface of the pipette tip. In this example, the radial extension takes the form of an annular groove 124 that externally engages the pipette tip mounting sleeve 123.

[0050] The pipette tip clamping plate 125 has an array of holes 126 extending axially through the thickness of the pipette tip clamping plate 125. The array of holes 126 corresponds in number and location to the array of holes 122 of the pipette tip mounting plate 121. The pipette tip clamping plate 125 also includes an array of pipette tip clamping members 127, each associated with one of the plurality of pipette tip mounts 123. In this example, the array of pipette tip clamping members 127 is provided in the form of a plurality of clamping sleeves 127 defined by regions of the pipette tip clamping plate 125 directly surrounding the holes 126 defined in the pipette tip clamping plate 125. Each clamping sleeve 127 has a clamping region 128, the inner diameter of which is larger than the outer diameter of its corresponding pipette tip mounting sleeve. In this way, when the suction tube tip clamping mechanism is engaged, a small gap is provided between the outer surface of the tip mounting sleeve 123 and the inner surface of the clamping area 128, such as... Figure 7 As shown.

[0051] Each clamping sleeve can have a substantially constant inner diameter. Alternatively, as... Figure 7As shown, each clamping sleeve can have a region with a different inner diameter. In the example shown, each clamping sleeve 127 has a narrow region 129A facing its upper end and a tapered region 129B located at its lower end. In the tapered region 129B, the inner diameter of the clamping sleeve 127 gradually decreases from the lowermost end to the clamping region 128. With this arrangement, one or more pipette tips can be semi-secured by positioning them in an intermediate "pre-locked" position in the pipette tip clamping plate 125, in which the tapered region 129B of the clamping sleeve 127 is adjacent to a recess 124 on the outer surface of the tip mounting sleeve 123. This facilitates the pickup of a parts array of tips from the tip box. Once the picked-up tip has been raised above the unpicked array, the picked-up tip can be clamped in place by moving the pipette tip clamping plate 125 to the clamping position. A small clearance can be provided between the narrow area 129A of the clamping sleeve 127 and the outer surface of the pipette tip mount 123. This helps to minimize the force required to move the pipette tip clamping plate 125 axially and contributes to the smooth operation of the pipette tip clamping mechanism.

[0052] like Figures 2 to 4 As best shown, the pipette tip clamping drive mechanism 130 includes a rotary actuator 131 and a threaded shaft 132 operatively connected to the output shaft of the rotary actuator 131. The rotary actuator 131 is mounted on a tip motor support plate 135 fixed relative to the pipette tip mounting plate 121. In this example, the tip motor support plate 135 is mounted on the outer surface of the lower head chassis component 103. The tip motor support plate 135 is located above an extension plate 133 fixed relative to the pipette tip clamping plate. The extension plate 133 includes a threaded hole 133A through which the threaded shaft 132 extends. The pipette tip clamping mechanism 130 also includes a plurality of guide rods 134 through which the pipette tip mounting plate 121 and the pipette tip clamping plate 125 are connected. In the illustrated embodiment, guide rods 134 are fixed relative to pipette tip mounting plate 121, and each guide rod 134 extends axially through a corresponding hole 137 in the pipette tip clamping plate 125. It should be understood, of course, that the guide rod can also be fixed relative to the pipette tip clamping plate and extend through holes in the pipette tip mounting plate or any other component of the pipette tip fixed relative to the pipette tip mounting plate.

[0053] When the rotary actuator 131 operates, the threaded shaft 132 rotates within the threaded hole 133A to drive the extension plate 133 toward or away from the pipette tip motor support plate 135, thereby causing the pipette tip clamping plate 125 to move axially toward or away from the pipette tip mounting plate 121. The direction of movement is determined by the rotation direction of the actuator 131. As the pipette tip clamping plate 125 moves axially toward or away from the pipette tip mounting plate 121, the guide rod 134 helps maintain the parallel relationship between the pipette tip mounting plate 121 and the pipette tip clamping plate 125.

[0054] like Figure 5 and Figures 8 to 11 As best shown, the plunger clamping mechanism 140 includes a plunger mounting plate 141, a plunger clamping plate 145 located above the plunger mounting plate 141, and a plunger clamping drive mechanism 150 operable to drive relative movement between the plunger mounting plate 141 and the plunger clamping plate 145. The plunger clamping mechanism 140 also includes a plunger clamping motor mount 155 located above the plunger mounting plate 141 and the plunger clamping plate 145, with an actuation motor of the plunger clamping drive mechanism 150 supported on the plunger clamping motor mount 155. The plunger mounting plate 141 and the plunger clamping motor mount 155 are fixed relative to each other. In this example, the plunger mounting plate 141 and the plunger clamping motor mount 155 are provided as separate components, which are joined together for ease of manufacture and assembly. In other examples, the plunger mounting plate 141 and the plunger clamping motor mount 155 may be provided as a single component. The plunger clamping drive mechanism 150 is configured to move the plunger clamping plate 145 toward and away from the plunger mounting plate 141 to selectively engage the plunger clamping mechanism 140.

[0055] like Figure 8 and Figure 9As best shown, the plunger mounting plate 141 has an array of holes 142 extending axially through the thickness of the plunger mounting plate 141. Securing within each hole 142 is a plunger mount 143 extending downward in an axial direction from the plate 141 and configured to engage with one of the plungers during use. Each plunger mount 143 is in the form of a tubular plunger mounting sleeve held in one of the arrays of holes 142. In this example, each plunger mount 143 has a shoulder with an outer diameter greater than the diameter of the hole 142 and abuts against the lower side of the plunger mounting plate 141. This shoulder helps to set the height of the plunger mounting sleeve 143 when initially inserted into the hole 142 of the plunger mounting plate 141. The lower end of the suction head mounting sleeve 143 preferably has an inwardly tapered end face to facilitate insertion of the plunger into the hole of the plunger mounting sleeve 143. Each plunger mounting sleeve 143 includes a radially extending feature on its inner surface, which is configured to form a snap-fit ​​connection with a correspondingly shaped feature on the outer surface of the plunger. In this example, the radially extending feature is in the form of an annular groove 144 in the inner surface of the plunger mounting sleeve 143 toward its lower end.

[0056] The plunger clamping plate 145 has an array of axially extending grooves or holes 146. The array of holes 146 in the plunger clamping plate 145 corresponds in number and position to the array of holes 142 in the plunger mounting plate 141. The array of holes 146 in the plunger clamping plate 145 may also correspond in number to the array of holes 122 and the array of holes 126 in the pipette tip clamping mechanism. The plunger clamping plate 145 also includes an array of plunger clamping members 147, each associated with one of a plurality of plunger mounts 143. The array of plunger clamping members is provided in the form of a plurality of clamping rods 147 extending axially from the plunger clamping plate 145 and into holes defined within the plunger mounting sleeve 143. Each clamping rod 147 has an enlarged head 148 at its lower end, which extends from a narrower neck region 149A. The outer diameter of the enlarged head 148 is smaller than the inner diameter of the plunger mounting sleeve 143. In this way, a small clearance is provided between the outer surface of the enlarged head 148 and the inner surface of the plunger mounting sleeve 143 when the plunger clamping mechanism is engaged. The outer diameter of the neck 149A is smaller than the outer diameter of the enlarged head 148. Preferably, each clamping rod 147 also has a spindle 149B, the outer diameter of which is substantially the same as the inner diameter of the region of the plunger mounting sleeve 143 in which it resides. The spindle 149B moves axially along the bore in the plunger mounting plate 143 as the plunger clamping plate 145 moves axially up and down relative to the plunger mounting plate 141.

[0057] like Figure 13As best illustrated, the plunger clamping drive mechanism 150 includes a rotary actuator 151 and a threaded shaft 152 operatively connected to the output shaft of the rotary actuator 151. The rotary actuator 151 is mounted on the plunger clamping motor mount 155 and thus fixed relative to the plunger mount plate 141. The rotary actuator 151 is located above a bore portion 153 of the plunger clamping plate 145 having a threaded hole 153A through which the threaded shaft 152 extends. The plunger clamping mechanism 150 also includes a plurality of guide rods 154 operatively connected to the plunger mount plate 141 and the plunger clamping plate 145 via the guide rods 154. In the illustrated embodiment, the guide rods 154 are fixed relative to the plunger clamping plate 145, and each guide rod 154 extends axially into a bore of a corresponding cylindrical housing 157 extending from the underside of the plunger clamping motor mount 155. Of course, it should be understood that the guide rod can also be fixed relative to the plunger mounting plate 141 and extend through the hole in the plunger clamping plate 145 or any other part of the pipette head fixed relative to the plunger clamping plate 145.

[0058] When the rotary actuator 151 operates, the threaded shaft 152 rotates within the threaded bore 153A to drive the plunger clamping plate 145 axially toward or away from the plunger mounting plate 141. As the plunger clamping plate 145 moves axially toward or away from the plunger mounting plate 141, the guide rod 154 helps maintain the parallel relationship between the plunger mounting plate 141 and the plunger clamping plate 145. The direction of movement is determined by the rotation direction of the actuator 151. This can be achieved... Figure 10 and Figure 11 As seen in the image, the plunger mounting plate 141 has been omitted for clarity. Figure 10 As can be seen, the guide rod 154 extends from the cylindrical housing 157, causing the plunger clamping plate 145 and its support plate 156 to be positioned at a lower level away from the underside of the plunger clamping motor mounting part 155, and closer to the upper surface of the plunger mounting plate. Figure 10 and Figure 11 (Not shown in the image). This is the clamping position. Figure 11In this configuration, the guide rod 154 retracts into the cylindrical housing 157, causing the plunger clamping plate 145 and its support plate 156 to move axially away from the plunger mounting plate 141 and toward the plunger clamping motor mounting plate 155. This is the release position. The relative movement between the plunger clamping plate 145 and the plunger mounting plate 141 allows the plunger clamping mechanism 140 to move to any position between the engaged and disengaged positions (or "release" positions or states). In the engaged position, the plunger is clamped in place, and in the disengaged position (or "release" position or state), the plunger can engage axially with or be removed from the plunger mounting member. The plunger clamping mechanism 140 can be configured to move to a pop-out position, in which the plunger clamping plate 145 moves toward the plunger mounting plate 141 beyond the clamping position. In this position, the enlarged head 148 of the clamping rod 147 is axially below a radially extending feature on the inner surface of the plunger mounting sleeve 143, which aligns with the narrower neck 149A of the clamping rod. This allows the top of the plunger (i.e., the plunger connector assembly) to bend inward. Further downward movement of the clamping plate 145 and the clamping rod 147 pushes the plunger downward to release it from the snap-fit ​​connection with the plunger mounting sleeve. When the pipette tip clamping plate 125 is also in the released position, further downward movement of the clamping rod pushes the plunger against one or more inner surfaces of the pipette tip (e.g., the area around the orifice at the distal end of the pipette tip) using the plunger clamping drive mechanism to push the pipette tip away from the tip clamping mechanism. This ejects the entire pipette assembly from the pipette tip. Alternatively, by using the direct drive actuator 160, the clamping rod and the plunger can move downward together to push the pipette, thereby ejecting the pipette tip from the device. In this ejection mode, the plunger can remain on the device even after the pipette tip has been ejected.

[0059] Figure 12 and Figure 13The direct drive actuator 160 is shown in more detail. The direct drive actuator 160 includes an actuator motor 161 mounted on the top surface of the upper head chassis 102. The output shaft of the actuator motor 161 is connected to a screw 162, which is connected to a ball screw actuator nut 163. The output shaft of the actuator 161 may be integral with or fixed to the screw 162. In the illustrated embodiment, the output shaft is connected to the screw via a rotary rigid coupling in the form of a bellows coupling 161A. The bellows coupling 161A allows relative axial movement between the output shaft and the threaded shaft 162, but prevents or substantially prevents relative rotation between the two components. The nut 163 is fixed to a ball screw mount 164 so that both can move simultaneously. In the illustrated embodiment, the ball screw mount 164 is fixed to a plunger clamping motor mount 155 at the upper end of the plunger clamping mechanism 140. In other embodiments, the ball screw mount 164 may be integrated with the plunger clamping motor mount 155. Therefore, the direct drive actuator 160 extends between the head chassis 101 and the plunger clamping mechanism 140.

[0060] When the actuator motor 161 is running, the entire plunger clamping mechanism 140 moves axially toward or away from the pipette tip clamping mechanism 120 along the guide rod 165, depending on the rotation direction of the actuator motor 161. The guide rod 165 is unthreaded. The plunger mounting plate 141 includes multiple guide sleeves 166 (see...). Figure 8 A guide rod 165 extends through the guide sleeve 166. When the actuator motor 161 operates, the guide sleeve 166 slides along the outer surface of the guide rod. In this way, the plunger clamped by the plunger clamping mechanism 140 can be rapidly accelerated relative to the pipette tip, extending within the pipette tip without any limitation imposed by the operating speed of the clamping mechanism. This allows the device to be used in non-contact dispensing modes (also known as jet dispensing, where liquid is dispensed from the pipette to a distance from the target, such that the droplet separates from the tip before contacting the target) and contact dispensing modes (where a droplet forms at the pipette tip and deposits upon contact with the target). When performing non-contact dispensing, the liquid sample must detach from the tip at a sufficiently high speed. For dispensing injections, the distance the plunger travels can be very small, for example, within 1 mm or less. Therefore, a high level of acceleration / deceleration is required to achieve the target speed for non-contact dispensing. Direct drive arrangements (e.g., via ball screws) can provide a higher level of heavy-load acceleration / deceleration than belt-driven systems, enabling non-contact dispensing of low-volume liquid samples. Furthermore, direct drive devices offer greater positional accuracy and repeatability compared to equivalent belt-driven mechanisms. This has a significant impact on dispensing performance.

[0061] Figures 14 to 17 It shows the relationship with Figures 2 to 13 A pipette 1010 used in conjunction with a pipette tip. The pipette 1010 includes a pipette tip 1100 and a plunger 1200.

[0062] The pipette tip 1100 can be a container for receiving and / or containing sample fluid or sample liquid. The pipette tip 1100 can be configured to be inserted into a container of sample liquid, or into a sample liquid. The pipette tip 1100 has a proximal end 1101 and a distal end 1102, defining a longitudinal axis 1001 between the proximal end 1101 and the distal end 1102. The pipette tip 1100 has an orifice 1108 at its distal end 1102, such as... Figure 15 As shown. The orifice 1108 may be defined at its distal end 1102 (specifically, at the outermost distal end of the pipette tip 1100) by the inner wall surface 1111 of the pipette tip 1100. The orifice 1108 may be of any suitable shape, such as elliptical, oval, or circular. The pipette tip 1100 has a fluid cavity 1109 extending at least partially from the orifice 1108 toward the proximal end 1101. This fluid cavity may be configured to receive and / or retain fluid, such as an air gap or sample liquid. The fluid cavity 1109 may be substantially elongated. This fluid cavity may be defined by the inner wall surface of the pipette tip 1100. A longitudinal axis 1001 may be a central axis around which the pipette tip 1100 and / or plunger 1200 are arranged. The longitudinal axis 1001 may define a central axis around which the pipette tip 1100 and / or plunger 1200 are arranged uniformly or symmetrically. The pipette tip 1100 and / or plunger 1200 may be configured such that the direction of aspiration and / or dispensing is along the longitudinal axis 1001. The pipette tip 1100 may be substantially elongated and extend between its proximal end 1101 and distal end 1102. The pipette tip 1100 may be substantially or entirely hollow. The pipette tip 1100 may comprise or be composed of a polymeric material. The pipette tip 1100 may comprise or be composed of a homogeneous material. The pipette tip 1100 may comprise or be composed of a translucent or transparent material.

[0063] The pipette tip 1100 may include a series of components, each with different functions, distinguishing features, and / or different shapes or sizes. The pipette tip 1100 may include one or more of the following: a tip connector component 1103, a centering portion 1104, a support portion 1105, a body portion 1106, and a bridging portion 1107, for example... Figure 15As shown. From the proximal end 1101 to the distal end 1102, each component may be arranged in the following order: tip connector component 1103, centering part 1104, support part 1105, body part 1106, bridging part 1107, and end 1110. A fluid chamber 1109 may extend through one, more, or all of the components of the pipette tip 1100. A plunger 1200 may extend through one, more, or all of the components of the pipette tip 1100.

[0064] The pipette tip connector component 1103 is configured for connection to a liquid handling system (e.g., via a snap-fit ​​connection). The pipette tip connector component 1103 may include a split tubular wall 1120 defined by a plurality of flexible segments 1121. The flexible segments 1121 are configured to resiliently deflect in a radially outward direction to increase the outer diameter of the proximal end 1101 of the pipette tip 1100 from a first outer diameter to a second outer diameter, wherein in the first outer diameter the flexible segment is not deflected and the pipette tip connector component is stationary, and in the second outer diameter the flexible segment is radially outwardly deflected and the pipette tip connector component is in an expanded state. In the illustrated embodiment, the pipette tip connector component 1103 includes four axially extending discontinuities or slots 1122 located within the tubular wall 1120, which separate the four flexible segments 1121. The pipette tip connector assembly 1103 may include any suitable number of axially extending interruptions 1122 to define any number of flexible segments 1121 (e.g., two, three, four, five, or six). The arrangement of the flexible segments 1121 and slots 1122 allows the pipette tip connector assembly to expand without requiring significant force to be applied to it. This reduces the insertion force required to engage the pipette tip connector assembly 1103 with the pipette tip.

[0065] The pipette tip connector component 1103 may further include one or more radially extending features 1123 located on its inner surface, through which a pipette tip can be connected. The radially extending features on the inner surface of the pipette tip connector component 1103 may include radially inwardly extending protrusions and / or radially outwardly extending recesses or grooves. The radially extending features may extend circumferentially. In the illustrated embodiment, the radially extending features on the inner surface of the pipette tip connector component 1103 include a portion of an annular rib 1123 protruding from the inner surface of the pipette tip connector component 1103. Preferably, the second outer diameter of the pipette tip connector component is larger than the first outer diameter by at least the radial extent of the radially extending feature 1123. The rib 1123 preferably includes angled upper and lower surfaces along which the inner diameter of the pipette tip connector component gradually increases from the rib 1123 to the region of the pipette tip connector component above and below the rib 1123. The angle of the upper surface can be selected according to the required insertion force. The angle of the lower surface can be selected according to the required ejection force. The upper or lower surface may each be at an angle of 10 to 80 degrees to the axial direction of the pipette tip, for example, at 20 to 70 degrees, 30 to 60 degrees, or 40 to 50 degrees to the axial direction of the pipette tip.

[0066] The centering portion 1104 can be configured to center the plunger 1200 within the pipette tip 1100. The centering portion 1104 can have a tapered or conical inner surface. The support portion 1105 may include one or more structural ribs or rings configured to reduce the flexibility of the pipette tip 1100 and / or improve its structural integrity. The one or more ribs may extend (e.g., axially) along at least a portion of the length between the proximal end 1101 and the distal end 1102 on the outer surface of the pipette tip, such as... Figure 16 As best shown. The body portion 1106 may be generally cylindrical and / or elongated. The body portion 1106 may have a substantially uniform inner diameter and / or outer diameter. The body portion 1106 may extend at least half the length of the pipette tip 1100. The body portion 1106 may have an inner diameter and / or outer diameter larger than any diameter of the end portion 1110. The bridging portion 1107 may be configured to bridge the body portion 1106 to the end portion 1110. The bridging portion 1107 may define a gradual transition or step between the body portion 1106 and the end portion 1110. The bridging portion 1107 may be generally conical, conical, and / or dome-shaped.

[0067] The plunger 1200 has a proximal end 1201 and a distal end 1202 extending along a longitudinal axis 1101. The plunger 1200 is configured to extend at least partially into an end portion 1110 between the proximal end 1101 and the distal end 1102 of the pipette tip 1100. The plunger 1200 may be configured to extend substantially or completely into the end portion 1110 between the proximal end 1101 and the distal end 1102 of the pipette tip 1100. The plunger 1200 is movable toward and away from the orifice 1108 to draw or dispense fluid from the pipette tip 1100. The plunger 1200 may have an end outer wall surface 1212 configured to align with an inner wall surface 1111 of the pipette tip 1110. The plunger 1200 may comprise or be composed of a polymeric material. The plunger 1200 may comprise or be composed of a homogeneous material.

[0068] The plunger 1200 may include a series of components, each with different functions, distinguishing features, and / or different shapes or sizes. The plunger 1200 may include one or more: a plunger connector component 1203, a centering portion 1204, a body portion 1206, and a sealing portion 1207. From the proximal end 1201 to the distal end 1202, each component may be arranged in the following order: connector component 1203, centering portion 1204, body portion 1206, sealing portion 1207, and end portion 1210.

[0069] A plunger connector component 1203 is configured for connection to a liquid handling system (e.g., via a snap-fit ​​connection). The plunger connector component 1203 may be configured to be fully received within a pipette tip connector component 1103 of a pipette tip 100. The plunger connector component 1203 may include a split tubular wall 1220, which may be defined by a plurality of flexible segments 1221. The flexible segments 1221 may be configured to resiliently deflect in a radially inward direction to reduce the inner diameter of the proximal end 1201 of the plunger 1200 from a first inner diameter to a second inner diameter, in which the flexible segments are not deflected and the plunger connector component is at rest, and in the second inner diameter, the flexible segments are radially inwardly deflected and the plunger connector component is in a compressed state. In the illustrated embodiment, the plunger connector component 1203 includes three axially extending interruptions or slots 1222 located in the tubular wall 1220, which separate the three flexible segments 1221. The plunger connector component 1203 may include any suitable number of axially extending interruptions 1222 to define any number of flexible segments 1221. The arrangement of the flexible segments 1221 and slots 1222 allows the plunger connector component to be compressed without significant compressive stress. The plunger connector component 1203 may also include one or more radially extending features 1223 on its outer surface through which the plunger can be connected to a pipette tip. The radially extending features on the outer surface of the plunger connector component 1203 may include radially outwardly extending protrusions and / or radially inwardly extending recesses or grooves. The radially extending features may extend in a circumferential direction. In the illustrated embodiment, the radially extending features on the outer surface of the plunger connector component 1203 include a spherical head 1223 located at the upper end of the plunger, the spherical head 1223 being defined above an annular groove in the outer surface of the plunger connector component 1203. Preferably, the second inner diameter of the plunger connector component is reduced to be at least smaller than the first inner diameter by at least the radial extent of the radially extending feature 1223, i.e., at least half the difference between the outer diameter of the spherical head 1223 and the outer diameter of the narrowest part of the annular groove.

[0070] The plunger connector assembly 1203 may further include an inner wall 1224 extending laterally from the inner surface of the plunger connector assembly 1203. The inner wall 1224 may be located at the distal end of the flexible segment 1221. The inner wall 1224 may be located at the proximal end of the body portion 1206. The inner wall 1224 forms a constraint on the bore of the plunger connector assembly. This provides a surface against which the head of the clamping rod can eject the pipette. Figure 17 As shown, the inner wall 1224 can extend through the entire width of the inner bore of the plunger 1200. However, this is not necessarily the case. The inner wall 1224 only needs to limit the size of the bore to be smaller than the outer diameter of the clamping rod head.

[0071] The centering portion 1204 may include an annular shoulder. The centering portion 1204 may be substantially conical or dome-shaped. In the illustrated embodiment, the centering portion 1204 is a radially extending frustoconical shoulder. The centering portion 1104 of the pipette tip 1100 is preferably configured to receive and engage the centering portion 1204 of the plunger 1200 to align the plunger's center. Figure 14 In the illustrated embodiment, the two centering portions have corresponding geometries. The body portion 1206 of the plunger 1200 may be configured to be received within the body portion 1106 of the pipette tip 1100. The body portion 1206 may be substantially cylindrical and / or elongated. The body portion 1206 may have a substantially uniform diameter. The body portion 1206 may extend along at least half the length of the plunger (optionally, along at least two-thirds of the length of the plunger 1200). The diameter of the body portion 1206 may be larger than the diameter of the end portion 1210. The sealing portion 1207 of the plunger 1200 may be configured to be received within the bridging portion 1107 of the pipette tip 1100. The sealing portion 1207 may be configured to form a seal against the inner wall of the pipette tip 1100. The sealing portion 1207 forms a fluid-tight seal within the pipette tip, preventing fluid from flowing from the proximal side of the sealing portion 1207 to the distal side when the plunger 1200 is installed in the pipette tip 1100. The sealing portion 1207 may be at least partially flexible. The sealing portion 1207 may be configured to bridge the body portion 1206 to the end portion 1210. The sealing portion 1207 may define a step between the body portion 1207 and the end portion 1210. The sealing portion 1207 may be substantially conical, conical, and / or dome-shaped. The end portion 1210 of the plunger 1200 may be configured to be received in the end portion 1110 of the pipette tip 1100. The end portion 1210 may have a smaller diameter than the sealing portion 1207 and / or the body portion 1206.

[0072] Reference Figures 18 to 22 A method for connecting a pipette 1010 to the pipette head 100 of the present invention will now be described. Although the accompanying drawings, which are discussed below, show only a single pipette, it should be understood that one or more of the connection, aspiration, dispensing, and ejection operations discussed can be applied simultaneously to multiple pipettes. For example, when the pipette head includes 384 mounting elements, the following discussion applies to the simultaneous connection of 384 pipettes or any subset thereof.

[0073] exist Figure 18In this configuration, both the pipette tip clamping mechanism 120 and the plunger clamping mechanism 140 are in their released states. When the pipette tip clamping mechanism 120 is in the released state, the pipette tip clamping plate 125 is at its highest position, abutting against the underside of the pipette tip mounting plate 121. Crucially, in this position, the clamping area of ​​the tip clamping sleeve is axially offset from the annular groove surrounding the outer surface of the tip mounting sleeve. When the plunger clamping mechanism 140 is in its released state, the plunger clamping plate 145 is at its highest position, and the enlarged head 148 of the plunger clamping rod 147 is axially offset from the annular groove on the inner surface of each plunger mounting sleeve, as shown. Then, using a pipette tip Z-motor (not shown), the entire pipette head 100 is axially moved towards the array of pipettes 1010, such that the tip mounting sleeve is received within the tip connector assembly of the pipette tip 1100. During the insertion of the tip mounting sleeve 123 into the proximal end of the pipette tip 1100, the annular rib 1123 on each pipette tip 1100 bridging the outer surface of the tip mounting sleeve 123 causes the tip connector component of each tip to deflect outward to an extended position. For example... Figure 18 As shown, once the annular rib 1123 is received in the annular groove 124, the flexible segment returns to an undeflected or only partially deflected state. In this position, the pipette tip connector assembly is stationary, and each pipette tip 1100 is snap-fitted to its corresponding pipette tip mounting sleeve 123. This is step 1.

[0074] refer to Figure 19 Discuss step 2. In step 2, the pipette tip clamping mechanism 120 is engaged by lowering the pipette tip clamping plate 125 and removing it from the pipette tip mounting plate, as follows: Figure 19 As shown. This results in a tip clamping sleeve 127 extending around the tip connector component 1103 of each pipette tip 1100, such that the clamping area of ​​each tip clamping sleeve is adjacent to the snap-fit ​​connection between each pipette tip 1100 and its corresponding tip mounting sleeve 123. The inner diameter of the clamping area 128 is smaller than the expansion diameter of the tip connector component 1103; for example, it may be substantially the same as the unexpanded outer diameter or "first" outer diameter of the tip connector component. With this arrangement, the tip connector component 1103 is prevented from fully expanding, thereby preventing the radially extending feature 1123 on the inner surface of the pipette tip 1100 from being released from the groove 124 on the outer surface of the tip mounting sleeve 123. In this way, the pipette tip 1100 is "locked" or "clamped" in place without requiring any significant force to be applied to the tip connector component of the pipette tip 1100. This reduces the force required to engage the pipette tip clamping mechanism.

[0075] Between steps 1 and 2, the pipette tip clamping mechanism may optionally be moved to a partially engaged "pre-locked" position between a released and engaged state, in which the tapered region 129B of each clamping sleeve 127 is adjacent to a groove 124 on the outer surface of its corresponding tip mounting sleeve 123. This facilitates the pickup of a partial array of tips from the tip cassette by allowing the picked-up tip to be secured to the tip mount without interference between the pipette tip clamping plate and the unpicked tip array. Once the picked-up tip is lifted by the pipette tip over the unpicked array, the picked-up tip can be fully clamped in place by moving the pipette tip clamping plate 125 to the clamping position.

[0076] refer to Figure 20 Discuss step 3. In step 3, a direct-drive actuator is used to lower the entire plunger clamping mechanism 140. This causes the plunger mounting sleeve 143 to contact the plunger connector assembly 1203 at the upper or proximal end of the plunger 1200. Further downward movement of the plunger clamping mechanism 140 causes the inner surface of the plunger mounting sleeve 143 to bridging the outer surface of the plunger connector assembly, causing the plunger connector assembly to deflect inward to a retracted or compressed position, and allowing the spherical head 1223 at the top of the plunger 1200 to be received in a groove 144 on the inner surface of the plunger mounting sleeve 143. Figure 20 As shown, once the spherical head 1223 is received in the groove 144 on the inner surface of the plunger mounting sleeve 143, the flexible segment 1221 of the plunger connector component 1203 returns to an undeflected or partially deflected state. In this position, the plunger connector component is stationary, and each plunger 1200 is snap-fitted to its corresponding plunger mounting sleeve 143.

[0077] refer to Figure 21 Step 4 is discussed. In step 4, the plunger clamping plate 145 moves axially toward the plunger mounting plate 141 via the plunger clamping drive mechanism until the head 148 of the plunger clamping rod is adjacent to the snap-fit ​​connection between the plunger and the plunger mounting sleeve. When in the retracted state, the outer diameter of the head 148 of each clamping rod is larger than the inner diameter (or "second inner diameter") of the plunger. For example, it can be substantially the same as the inner diameter (or "first" inner diameter) of the undeflected plunger. This arrangement prevents the plunger connector assembly from fully retracting to the retracted position, thereby preventing the ball head 1223 of the plunger 1200 from releasing from the groove 144 on the inner surface of the plunger mounting sleeve 143. In this way, the plunger 1200 is "locked" or "clamped" in place without requiring any significant compressive force to be applied to the plunger connector assembly. This reduces the force required to engage the plunger clamping mechanism.

[0078] To perform the aspiration operation, the pipette tip 100 is moved to the desired position relative to a set of liquid samples using the pipette tip Z motor. Then, as... Figure 22 As shown, a direct-drive actuator is used to raise the plunger of each pipette within its respective pipette tip, thereby moving the entire plunger clamping mechanism away from the pipette tip clamping mechanism and drawing fluid into the pipette tip. Then, by moving the plunger clamping mechanism in the opposite direction using the direct-drive actuator, fluid can be dispensed as needed.

[0079] After the aspiration and dispensing operations are completed, the pipette can be ejected as follows. First, each plunger moves to the bottom of its stroke within its respective pipette tip, and the tip clamping mechanism 120 disengages by moving the tip clamping plate 125 toward the tip mounting plate 121, so that the clamping sleeve 127 is not aligned with the snap-fit ​​connection between each pipette tip and its respective tip mount 123, and the clamping sleeve 127 is moved away from the outer surface of the pipette tip. Next, the plunger clamping plate 145 moves toward the plunger mounting plate 141 beyond the engagement position, so that the head 148 of each clamping rod 147 is disengaged from the snap-fit ​​connection between each plunger 1200 and its corresponding plunger mount 143, and the neck 149A of each clamping rod 147 is aligned with the snap-fit ​​connection, causing the distal surface of the clamping rod head to abut against the inner wall 1224 of the plunger connector component 1203. Because the outer diameter of the neck 149A of the clamping rod 147 is smaller than the second compression inner diameter of the plunger connector assembly 1203, the plunger connector assembly is not restricted to inward deflection into a compressed state when the clamping rod is in this position. Therefore, the continued downward movement of the plunger clamping plate 145 releases the ball head 1223 of the plunger connector assembly 1203 from the corresponding radially extending feature 144 of the plunger mount 143 to remove the plunger 1200 from the pipette tip. Further downward movement of the plunger clamping plate, and consequently, further downward movement of the clamping rod and the plunger itself, pushes the distal portion of the plunger against the corresponding portion of the pipette tip where they reside. In this way, the plunger and plunger clamping mechanism can be used to release the pipette tip 1100 from the pipette tip mount 123, thereby ejecting the pipette 1010 from the pipette tip.

[0080] Although the invention has been described above with reference to one or more preferred embodiments, it should be understood that various changes or modifications may be made without departing from the scope of the invention as defined in the appended claims.

Claims

1. A pipette head for a liquid dispensing device, the pipette head being used with a pipette array, each pipette having a pipette tip and a plunger disposed within the pipette tip, the pipette head comprising: A pipette tip clamping mechanism is used to connect and clamp the pipette tips of the pipette array during use; and A plunger clamping mechanism for connecting and clamping the plungers of the pipette array during use; The pipette tip clamping mechanism includes: A pipette tip mounting plate having a plurality of pipette tip mounting parts, each pipette tip mounting part being configured to connect with one of the pipette tips during use; A pipette tip clamping plate having a plurality of pipette tip clamping components, each pipette tip clamping component being associated with one of the plurality of pipette tip mounting components; A pipette tip clamping drive mechanism includes an operable actuator to drive relative movement between the pipette tip clamping plate and the pipette tip mounting plate in the axial direction, thereby selectively engaging the pipette tip clamping mechanism by moving the pipette tip clamping mechanism between a clamping position and a release position. The plunger clamping mechanism includes: A plunger mounting plate having a plurality of plunger mounting members, each plunger mounting member being configured to connect with one of the plungers during use; A plunger clamping plate having a plurality of plunger clamping members, each plunger clamping member being associated with one of the plurality of plunger mounts; A plunger clamping drive mechanism includes an operable actuator to drive relative movement between the plunger clamping plate and the plunger mounting plate in the axial direction, thereby selectively engaging the plunger clamping mechanism by moving the plunger clamping mechanism between a clamping position and a release position. The pipette tip further includes a drive actuator operably capable of moving the plunger clamping mechanism toward or away from the plate of the pipette tip clamping mechanism in the axial direction to aspirate or dispense liquid during use. The drive actuator includes a drive mechanism separate from the pipette tip clamping drive mechanism and the plunger clamping drive mechanism, such that the drive actuator is configured to operate independently of the pipette tip clamping drive mechanism and the plunger clamping drive mechanism.

2. The pipette tip according to claim 1, wherein, The drive actuator is a direct drive actuator.

3. The pipette head according to claim 2 further includes a chassis, wherein, The drive actuator is a ball screw actuator, which includes a ball screw and a motor fixed relative to the chassis. The motor is connected to the plunger clamping mechanism via the ball screw.

4. The pipette tip according to claim 1, wherein, The plunger clamping drive mechanism includes a plurality of guide rods, the plunger clamping plate being operably connected to the plunger mounting plate via the guide rods, and the plunger clamping plate and the plunger mounting plate being movable relative to each other in the axial direction along the guide rods via an actuator of the plunger clamping mechanism. The plurality of guide rods are movable in the axial direction together with the plunger clamping plate and the plunger mounting plate toward and away from the plate of the pipette tip clamping mechanism via the drive actuator.

5. The pipette tip according to claim 1, wherein, The plunger clamping drive mechanism includes a threaded shaft connected to an actuator of the plunger clamping drive mechanism and extending through a threaded hole fixed relative to one of the plunger mounting plate and the plunger clamping plate, such that when the threaded shaft is rotated by the actuator, the threaded shaft drives relative movement between the plunger clamping plate and the plunger mounting plate in the axial direction.

6. The pipette tip according to claim 1, wherein, The pipette tip clamping drive mechanism includes a threaded shaft connected to an actuator of the pipette tip clamping drive mechanism and extending through a threaded hole fixed relative to one of the pipette tip mounting plate and the pipette tip clamping plate, such that when the threaded shaft is rotated by the actuator, the threaded shaft drives relative movement between the pipette tip clamping plate and the pipette tip mounting plate in the axial direction.

7. The pipette tip according to claim 1, wherein, The pipette tip clamping plate is located below the pipette tip mounting plate.

8. The pipette tip according to claim 1, wherein, The plurality of pipette tip clamping components include a plurality of sleeves, the plurality of sleeves defining a clamping area and being coaxial with the plurality of pipette tip mounting components, and when the pipette tip clamping mechanism is engaged, the plurality of sleeves are externally connected to the plurality of pipette tip mounting components.

9. The pipette tip according to claim 8, wherein, The plurality of sleeves are defined by holes in the pipette tip clamping plate.

10. The pipette tip according to claim 8, wherein, Each of the plurality of pipette tip mounts includes a radially extending feature on its outer surface, the radially extending feature being configured to form half of a snap-fit ​​connection, wherein, when the pipette tip clamping mechanism is in the clamped position, the clamping area of ​​each of the plurality of sleeves is axially adjacent to the radially extending feature on the outer surface of the associated pipette tip mount, and when the pipette tip clamping mechanism is in the released position, the clamping area of ​​each of the plurality of sleeves is axially offset from the radially extending feature on the outer surface of the associated pipette tip mount.

11. The pipette tip according to claim 1, wherein, The plurality of plunger mounting components include a plurality of axially extending sleeves, and wherein the plurality of plunger clamping components include a plurality of axially extending clamping rods that extend within the plurality of axially extending sleeves when the plunger clamping mechanism is in the clamping position.

12. The pipette tip according to claim 11, wherein, Each of the plurality of axially extending sleeves includes a radially extending feature on its inner surface, the radially extending feature being configured to form half of a snap-fit ​​connection, and wherein, when the plunger clamping mechanism is in the clamping position, the clamping area of ​​each of the plurality of clamping rods is axially adjacent to the radially extending feature on the inner surface of the plunger mount associated therewith, and when the plunger clamping mechanism is in the release position, the clamping area of ​​each of the plurality of clamping rods is axially offset from the radially extending feature on the inner surface of the plunger mount associated therewith.

13. The pipette head according to claim 10, further comprising at least one pipette tube, said at least one pipette tube comprising: A pipette tip having a distal end with a dispensing orifice and a proximal end with a tip connector assembly for connecting the pipette tip to the pipette tip during use; and A plunger having a distal end located inside the pipette tip and a proximal end with a hollow plunger connector assembly for connecting the plunger to a plunger clamping mechanism of the pipette tip during use. The pipette tip connector component has a radially extending feature on its inner surface, the radially extending feature being configured to form a snap-fit ​​connection with a radially extending feature on the outer surface of one of the plurality of pipette tip mounts, and configured to elastically deflect radially outward from a rest position to an extended position. In the rest position, the pipette tip connector component has a first outer diameter, and in the extended position, the pipette tip connector component has a second outer diameter, the second outer diameter being larger than the first outer diameter and at least larger than the radial range of the radially extending feature of the pipette tip connector component. In this device, the clamping area of ​​each of the multiple sleeves of the suction head clamping mechanism has an inner diameter that is greater than or equal to the first outer diameter of the suction head connector component and less than the second outer diameter of the suction head connector component, such that the clamping area prevents the suction head connector component from deflecting to the extended position, thereby releasing the snap-fit ​​connection when the suction head clamping mechanism is in the clamping position.

14. The pipette head according to claim 12, further comprising at least one pipette tube, said at least one pipette tube comprising: A pipette tip having a distal end with a dispensing orifice and a proximal end with a tip connector assembly for connecting the pipette tip to the pipette tip during use; and A plunger having a distal end located inside the pipette tip and a proximal end with a hollow plunger connector assembly for connecting the plunger to a plunger clamping mechanism of the pipette tip during use. The plunger connector component has a radially extending feature on its outer surface, the radially extending feature being configured to form a snap-fit ​​connection with a radially extending feature on the inner surface of one of the plurality of plunger mounts, and configured to resiliently deflect radially inward from a rest position to a compressed position. In the rest position, the plunger connector component has a first inner diameter; in the compressed position, the plunger connector component has a second inner diameter, the second inner diameter being smaller than the first inner diameter and at least smaller than the radial extent of the radially extending feature of the plunger connector component. Each of the plurality of axially extending clamping rods has a clamping area having an outer diameter that is less than or equal to a first inner diameter of the plunger connector component and greater than a second inner diameter of the plunger connector component, such that the clamping area prevents the plunger connector component from deflecting to the compressed position, thereby releasing the snap-fit ​​connection when the plunger clamping mechanism is in the clamping position.

15. A liquid dispensing device, comprising: The main body has a microporous plate receiving area; and The pipette according to any one of claims 1 to 14 is located above the receiving area of ​​the microplate.

Images