Pipette tips for liquid dispensing devices

Abstract

A pipetting head for a liquid dispensing apparatus is provided. The pipetting head has a pipette tip coupling mechanism and a plunger clamping mechanism. The plunger clamping mechanism has a plurality of mounts for holding plungers of multiple pipettes during use, a plurality of clamping rods each extending into one of the mounts, and a clamping drive mechanism operable to cause relative movement between the mounts and the clamping rods to selectively engage the clamping mechanisms. The mounts each have a radially extending mechanism configured to form one half of a snap-fit ​​connection. A clamping region of each of the clamping rods is axially adjacent to the radially extending mechanism of its associated mount when in the clamped position and is axially offset from the radially extending mechanism of its associated mount when in the released position. The clamping rod prevents the snap-fit ​​connection with the plunger from being released when in the clamped position.

Description

Technical Field

[0001] The present invention relates to a pipette operation head for a liquid dispensing device, particularly a pipette operation head having a pipette tip connection mechanism and a plunger connection mechanism. With the pipette tip connection mechanism and the plunger connection mechanism, a pipette having a pipette tip and a plunger can be firmly attached to the pipette operation head.

Background Art

[0002] It is known to use a pipette for sucking or dispensing a liquid sample.

[0003] It is also known to use a pipette having a plunger provided on a pipette tip. A typical pipette, known as a "volumetric" pipette, uses a plunger or piston to suck or dispense a liquid either by direct contact with the sample liquid or through a small air gap. During use, the pipette tip and the plunger are attached to the pipette operation head of a liquid dispensing device. The pipette operation head moves the plunger relative to the tip and sucks or dispenses the liquid from the opening at the distal end of the pipette tip. Such pipettes are used in automated machines and can improve the accuracy and reproducibility of pipette operation movements.

[0004] The inventors have identified several problems with the way pipettes are connected to known pipette operation heads for liquid dispensing devices.

[0005] An improved pipette operation head is needed.

Summary of the Invention

[0006] A first aspect of the present invention is a pipette operating head for a liquid dispensing apparatus for use with a plurality of pipettes, each having a pipette tip and a plunger provided within the pipette tip, wherein the pipette operating head comprises a pipette tip coupling mechanism having a plurality of tip mounts for holding the pipette tips of the plurality of pipettes in use; and a plunger coupling mechanism having a plurality of plunger mounts for holding the plungers of the plurality of pipettes in use, each of the plurality of tip mounts having a radially extending mechanism configured to form half of a snap-fit ​​coupling, and the pipette tip coupling mechanism comprises a plurality of tip clamping members, each associated with one of the plurality of tip mounts and each having a clamping area A pipette tip tightening mechanism is provided, further comprising: a tip tightening drive mechanism having an actuator that can be operated to selectively engage the pipette tip tightening mechanism by causing relative movement between a tip mount and a tip tightening member in the axial direction, thereby moving the pipette tip tightening mechanism between a clamped position and a released position, wherein the tightening area of ​​each tip tightening member is axially adjacent to a mechanism extending radially on the outer surface of its associated tip mount when the pipette tip tightening mechanism is in the clamped position, and the tightening area of ​​each tip tightening member is axially offset from the mechanism extending radially on the outer surface of its associated tip mount when the pipette tip tightening mechanism is in the released position, providing a pipette operating head.Alternatively, or in addition, each of a plurality of plunger mounts has a radially extending mechanism on its inner surface configured to form half of a snap-fit ​​connection, the plunger connection mechanism further comprising: a plurality of plunger clamping members, each associated with one of the plurality of plunger mounts and each having a clamping region; and a plunger clamping drive mechanism having an actuator operable to selectively engage the plunger clamping mechanism by causing relative movement between the plunger mount and the plunger clamping members in the axial direction and moving the plunger clamping mechanism between a clamped position and a released position, wherein the clamping region of each plunger clamping member is axially adjacent to the radially extending mechanism on the inner surface of its associated plunger mount when the plunger clamping mechanism is in the clamped position, and the clamping region of each plunger clamping member is axially offset from the radially extending mechanism on the inner surface of its associated plunger mount when the plunger clamping mechanism is in the released position.

[0007] This provides a very compact configuration in which a large number of pipettes can be precisely and securely mounted to the pipette operating head. This is particularly useful in liquid dispensing devices intended for use with standard 384-well plates, as the compact configuration provides 384 mounting collars and locking members, allowing 384 pipettes to be held in a 16x24 matrix. This allows for aspirating liquid from or dispensing liquid into a conventional 384-well plate in a single operation. As used herein, the terms “clamping” and “clamp” refer to a configuration in which the pipette tip or plunger is attached together in place, locked, and prevented from being accidentally removed. This is in contrast to a configuration in which the pipette tip or plunger is attached without locking, for example, using an interference fit or snap-fit ​​connection in which the pipette tip or plunger can be easily removed by axial pulling. The tightening configuration can also improve the accuracy of aspiration and dispensing operations by preventing small relative movements that may occur between the pipette operating head and the plunger or pipette tip.

[0008] Furthermore, by configuring the tip coupling mechanism as a tip tightening mechanism and / or the plunger coupling mechanism as a plunger tightening mechanism, the tightening members are movable to and from a register having the snap-fit ​​characteristics of the mount, and the pipette tip and / or plunger can be tightened to the correct position on the mount by limiting the deflection of the connector portion of the tip or plunger, preventing the snap-fit ​​connection with the mount from being released. This allows the pipette tip and / or plunger to be attached in place and securely tightened without having to apply a large force to the tip connector portion of the pipette tip and / or the plunger connector portion of the plunger. This reduces the force required to engage the pipette tip tightening mechanism and / or plunger tightening mechanism. This contrasts with some known tip coupling mechanisms in which tightening is achieved by expanding a collet inside the pipette tip and pressing it outward against the upper end of the pipette tip, thereby creating hoop stress inside the pipette tip. This also contrasts with some known plunger coupling mechanisms in which tightening is achieved by pressing a collet against the outer surface of the upper end of the plunger, thereby creating a compressive stress on the plunger.

[0009] Multiple tip clamping members may each have any suitable component that restricts the radial movement of the pipette tip in its associated tip mount when the pipette tip clamping mechanism is in the clamped position. Multiple tip clamping members may each have multiple sleeves that define a clamping area. The sleeves may be axially aligned with the multiple tip mounts. The sleeves may be coaxial with the multiple tip mounts. The sleeves may be discontinuous or continuous. The sleeves may surround the multiple tip mounts when the pipette tip clamping mechanism is in the clamped position. The sleeves may have a substantially constant inner diameter. The sleeves may have regions with different inner diameters.

[0010] The pipette tip clamping mechanism may include a pipette tip clamping plate, on which a plurality of tip clamping members are provided. The pipette tip clamping plate is axially movable relative to a plurality of pipette tip mounts, and the pipette tip clamping mechanism may be selectively engaged with the plate.

[0011] Multiple sleeves may be defined by one or more separate components fixed to the pipette tip clamping plate. Multiple sleeves may be defined by openings defined in the pipette tip clamping plate.

[0012] The radially extending mechanisms on the outer surface of each of the multiple tip mounts may have any suitable shape. The radially extending mechanisms on one or more of the outer surfaces of the multiple tip mounts may be recesses or grooves. This configuration is particularly suitable for use with pipette tips having correspondingly molded projections configured for receiving in the grooves. The radially extending mechanisms on the outer surface of each of the multiple tip mounts may be circumferential grooves. The circumferential grooves may have circumferential cuts. For example, the circumferential grooves may be partially annular.

[0013] In other embodiments, the radially extending mechanism on one or more outer surfaces of the tip mounts may be a projection. This configuration is particularly suitable for use with pipette tips having correspondingly molded recesses or grooves configured in the tip mount to receive the projection.

[0014] Multiple plunger mounts may comprise multiple axially extending sleeves. Multiple plunger clamping members may comprise multiple axially extending clamping rods, each defining a clamping area. The clamping rods may extend into the interior of the multiple axially extending sleeves when the plunger clamping mechanism is engaged. The sleeves may have a substantially constant inner diameter. Alternatively, the sleeves may have regions with different inner diameters. Each of the multiple axially extending sleeves may have multiple axial slots at their distal end. This can help enable compliance between the channel defined by the pipette operating head and the multiple pipettes attached to the pipette operating head.

[0015] Multiple clamping rods may each have an extended distal end connected to a narrower shaft, the extended distal end defining a clamping area. In this configuration, the clamping mechanism can be moved from a clamped position to a released position by moving the multiple clamping rods in any axial direction. This can facilitate the release of both the pipette plunger and pipette tip by moving the clamping rods downward, releasing the clamping mechanism and pushing the plunger and pipette tip out of their respective mounts.

[0016] A second aspect of the present invention provides a pipette for use with a pipette operating head described in the first aspect of the present invention, comprising: a pipette tip having a distal end having a dispensing opening and a proximal end having a tip connector portion for connecting the pipette tip to a pipette tip coupling mechanism of the pipette operating head during use; and a plunger having a distal end positioned inside the pipette tip and a proximal end having a hollow plunger connector portion for connecting the plunger to a plunger coupling mechanism of the pipette operating head during use. The tip connector portion has a radially extending mechanism on its inner surface configured to form a snap-fit ​​connection with a radially extending mechanism on one of the outer surfaces of a plurality of pipette tip mounts, and the tip connector portion is configured to be elastically deflected radially outward from a stationary position having a first outer diameter to an extended position having a second outer diameter that is larger than the first outer diameter by at least the radial range of the radially extending mechanism of the tip connector portion. Alternatively, or in addition, the plunger connector portion has a radially extending mechanism on its outer surface configured to form a snap-fit ​​connection with a radially extending mechanism on the inner surface of one of a plurality of plunger mounts, and the plunger connector portion is configured to be elastically deflected radially inward from a stationary position having a first inner diameter to a pushed-in position having a second inner diameter smaller than the first inner diameter by at least the radial range of the radially extending mechanism of the plunger connector portion.

[0017] The tip connector portion may comprise a segmented tubular wall defined by a plurality of flexible segments configured to elastically deflect radially outward, thereby deflecting the tip connector portion from a stationary position to an extended position. The flexible segments may be defined by a series of axially extending slits or slots in the tubular wall. The axially extending slits may be spaced equidistant from the longitudinal axis of the pipette. The axially extending slits may have the same or different axial lengths. The axially extending slits may be in line with the pipette axis or may form an angle with respect to the pipette axis.

[0018] The radially extending mechanism on the inner surface of the chip connector portion may include projections or ribs that protrude radially inward from the inner surface of the chip connector portion. This configuration is particularly suitable for use with chip mounts having correspondingly molded recesses or grooves configured to receive the projections or ribs of the chip connector portion. The projections or ribs may be circumferential ribs. The circumferential ribs may have circumferential cuts. For example, the circumferential ribs may be partially annular. Alternatively, or in addition, the radially extending mechanism on the inner surface of the chip connector portion may include recesses or grooves that extend radially outward into the inner surface of the chip connector portion. This configuration is particularly suitable for use with chip mounts having correspondingly molded projections or ribs configured to receive in the recesses or grooves of the chip connector portion.

[0019] The plunger connector may have a segmented tubular wall defined by a plurality of flexible segments configured to elastically deflect radially inward, deflecting the plunger connector from a resting position to a pushed-in position. The flexible segments may be defined by a series of axially extending slits or slots in the tubular wall. The axially extending slits may be spaced equidistant from the longitudinal axis of the pipette. The axially extending slits may have the same or different axial lengths. The axially extending slits may be in line with the pipette axis or may be at an angle to the pipette axis.

[0020] The mechanism extending radially from the outer surface of the plunger connector portion may include a molding head portion adjacent to a recess or groove extending radially inward into the outer surface of the plunger connector portion. The recess or groove defines the lower part of the molding head. The molding head may have substantially the same outer diameter as the region of the plunger connector portion directly below the recess or groove. This configuration is particularly suitable for use with a plunger mount having a correspondingly molded recess configured to receive the molding head of the plunger connector portion. The recess or groove of the plunger connector portion may be a circumferential groove. The circumferential groove may have a circumferential cut. For example, the circumferential groove may be partially annular. The second inner diameter to which the plunger connector portion narrows is smaller than the first inner diameter by at least the radial range of the radially extending mechanism, i.e., by at least half the difference between the outer diameter of the molding head and the outer diameter of the narrowest part of the annular recess directly below it.

[0021] Each clamping area of ​​the multiple sleeves of the chip clamping mechanism has an inner diameter that is greater than or equal to the first outer diameter of the chip connector portion and less than the second outer diameter of the chip connector portion, and when the chip clamping mechanism is in the clamping position, the clamping area may be configured to prevent the chip connector portion from being deflected to the expanded position, thereby preventing the snap-fit ​​connection from being released.

[0022] Each of the clamping areas of the multiple axially extending clamping rods may have an outer diameter less than or equal to the first inner diameter of the plunger connector and greater than the second inner diameter of the plunger connector, so that when the plunger clamping mechanism is in the clamp position, the clamping areas prevent the plunger connector from being pushed in to the push-in position, thereby preventing the snap-fit ​​connection from being released.

[0023] A liquid dispensing device is provided comprising: a main body having a microplate receiving area; and a pipette operating head according to the first aspect of the present invention, the pipette operating head being positioned above the microplate receiving area.

[0024] Further features and advantages of the present invention will be further described below by way of example with reference to the accompanying drawings.

Brief Description of the Drawings

[0025] [Figure 1] It is a perspective view of a liquid dispensing device having a pipette operation head according to the present invention. [Figure 2] It is a perspective view of a pipette operation head according to the present invention. [Figure 3] It is a side view of the pipette operation head of FIG. 2. [Figure 4] It is a perspective view of the pipette operation head of FIG. 2, with various parts omitted for clarity, and a pipette tip clamping mechanism and a plunger clamping mechanism are shown. [Figure 5] It is a cross-sectional view of the figure of FIG. 4, showing plates of a pipette tip clamping mechanism and a plunger clamping mechanism. [Figure 6] It is an enlarged cross-sectional perspective view of the figure of FIG. 4, showing a plate of a pipette tip clamping mechanism. [Figure 7] It is an enlarged cross-sectional view of a plate of a pipette tip clamping mechanism of the pipette operation head of FIG. 2, showing a pipette tip mounting sleeve. [Figure 8] It is an enlarged cross-sectional perspective view of the pipette operation head of FIG. 2, with various parts omitted for clarity, and a plate of a plunger clamping mechanism is shown in more detail. [Figure 9] It is an enlarged cross-sectional view of a plate of a plunger clamping mechanism of the pipette operation head of FIG. 2, showing a plunger mount and a clamping member. [Figure 10] It is a perspective view of a plunger clamping mechanism of the pipette operation head of FIG. 2, with a plunger mounting plate omitted for clarity, and a plunger clamping plate is shown in the clamping position. [Figure 11]Figure 2 is a perspective view of the plunger tightening mechanism of the pipette operating head. For clarity, the plunger mounting plate has been omitted, and the plunger tightening plate is shown in the released position. [Figure 12] Figure 2 is a cross-sectional front view of the pipette operating head. [Figure 13] Figure 2 is a cross-sectional side view of the pipette operating head. [Figure 14] This is a cross-sectional view of a pipette for use with the liquid dispensing system shown in Figure 1. [Figure 15] Figure 14 is a perspective view of the pipette tip and plunger of the pipette, with the plunger removed from the pipette tip. [Figure 16] Figure 14 is an enlarged cross-sectional view of the pipette, showing the tip connector and plunger connector sections in more detail. [Figure 17] Figure 14 is a perspective view of the pipette showing the tip mount and associated tip clamp of the pipette tip tightening mechanism. [Figure 18] This is an enlarged cross-sectional view of parts of the pipette tip tightening mechanism and plunger tightening mechanism at various stages of pipette coupling. [Figure 19] This is an enlarged cross-sectional view of parts of the pipette tip tightening mechanism and plunger tightening mechanism at various stages of pipette coupling. [Figure 20] This is an enlarged cross-sectional view of parts of the pipette tip tightening mechanism and plunger tightening mechanism at various stages of pipette coupling. [Figure 21] This is an enlarged cross-sectional view of parts of the pipette tip tightening mechanism and plunger tightening mechanism at various stages of pipette coupling. [Figure 22] This is an enlarged cross-sectional view of parts of the pipette tip tightening mechanism and plunger tightening mechanism at various stages of pipette coupling. [Modes for carrying out the invention]

[0026] Figure 1 shows a liquid dispensing device 10 for use with a number of volumetric pipettes 1010. The device 10 comprises a body 12 having a microplate receiving area or deck 14 and a pipette operating head 100 positioned above the microplate receiving area 14. The microplate receiving area 14 has a substantially horizontal top surface 16 positioned to receive laboratory microplates. The receiving area 14 may be located on a height-adjustable support structure 18, which can change the height of the microplate receiving area 14 as needed. The receiving area 14 may be configured to hold laboratory microplates in place. For example, the top surface 16 of the receiving area 14 may have one or more indentations (not shown) positioned to receive the microplate and prevent lateral movement of the microplate relative to the receiving area 14. The device 10 is typically used in the orientation shown in Figure 1, with gravity holding the product in the wells of the microplate. The axis labeled Z in Figure 1 therefore represents the upward direction, and gravity acting in the opposite direction holds the product in the wells of the microplate. References to upward and downward directions or axial directions therefore refer to movement along the axis labeled Z in Figure 1. References to lateral or transverse directions refer to movement in the directions labeled X and Y in Figure 1. References to vertical directions or height also therefore refer to dimensions or movement along the axis labeled Z in Figure 1. The pipette operating head 100 is configured to hold a number of pipettes, as shown below in relation to Figures 2 to 9, and is movable in relation to the deck 14, and may bring pipettes attached to the pipette operating head 100 close to a microplate supported on the deck 14 so that liquid is aspirated from or dispensed into the wells of the microplate.

[0027] Figures 2 to 4 show the pipette operating head 100 in more detail. The pipette operating head comprises a head chassis 101 having an upper head chassis portion 102 and a lower head chassis portion 103, both of which are bolted together to form the body of the pipette operating head 100. The upper and lower head chassis portions are connected to the body of the device by a chassis support plate 104. The chassis support plate 104 can preferably move the entire pipette operating head 100 in the X, Y, and Z directions relative to the receiving area of ​​the device in a conventional manner using one or more head actuators (not shown). The pipette operating head 100 further comprises a pipette tip coupling mechanism for coupling to the pipette tips of multiple volumetric pipettes during use, and a plunger coupling mechanism for coupling to the plungers of multiple volumetric pipettes.

[0028] In this embodiment, the pipette tip coupling mechanism is a pipette tip tightening mechanism 120 for coupling or joining to the pipette tips of multiple volumetric pipette tips and tightening them during use, and the plunger coupling mechanism is a plunger tightening mechanism 140 for coupling or joining to the plungers of multiple volumetric pipettes and tightening them during use. Thus, both are configured to coupling to and tighten the pipette tips and plungers, respectively. In other embodiments, the tightening characteristic of either the pipette tip coupling mechanism or the plunger coupling mechanism may be omitted, and the mechanism may only coupling to the pipette tip or the plunger, respectively.

[0029] When mounted on the upper head chassis 102, the direct drive actuator 160 can be operated during use to move the plunger clamping mechanism 140 axially toward or away from the plate of the pipette tip clamping mechanism, thereby enabling the aspirator or dispenser of liquid. The drive actuator may otherwise be an indirect drive actuator comprising a motor-driven belt or chain configured to move the plunger clamping mechanism relative to the pipette tip clamping mechanism and to operate independently of the pipette tip clamping drive mechanism and the plunger clamping drive mechanism. Preferably, the drive actuator is a direct drive actuator. Whether the drive actuator is a direct drive actuator or an indirect drive actuator having an independently operated drive actuator, the plunger clamping mechanism, and by extension any plungers attached thereto, can move relative to the pipette tip clamping mechanism and perform aspirator and dispensing operations independently of the mechanisms operating the pipette tip clamp and the plunger clamp. For example, if the drive actuator uses a drive mechanism comprising one or more screw rods, the pitch of the screw threads can be specifically matched to the desired speed of movement of the plunger clamping mechanism, rather than being determined by the operation of the plunger clamping mechanism itself. The direct drive actuator 160 is fixed in association with the head chassis 101 and extends between the head chassis 101 and the plunger clamping mechanism 140.

[0030] The pipette tip tightening mechanism 120 comprises a pipette tip mounting plate 121, a pipette tip tightening plate 125 positioned below the pipette tip mounting plate 121, and a pipette tip tightening drive mechanism 130 that can be operated to cause relative movement between the pipette tip mounting plate 121 and the pipette tip tightening plate 125. In this example, the pipette tip mounting plate 121 is provided as part of the lower head chassis, and the pipette tip tightening drive mechanism 130 is configured to move the pipette tip tightening plate 125 toward and away from the fixed pipette tip mounting plate 121, thereby selectively engaging the pipette tip tightening mechanism 120.

[0031] As is most commonly seen in Figures 5 to 7, the pipette tip mounting plate 121 has a number of openings 122 that extend axially through the thickness of the pipette tip mounting plate 121. When fixed within each opening 122, the pipette tip mount 123 extends downward axially from the plate 121 and is configured to connect with one of the pipette tips during use. Each pipette tip mount 123 is in the form of a tubular tip mount sleeve held in one of the number of openings 122. In this example, each opening 122 has a limiting portion having a diameter less than the outer diameter of the tip mount sleeve 123. The limiting portion prevents the tip mount sleeve 123 from being pushed upward through the tip mounting plate when the tip mount sleeve is first inserted into the pipette tip. The upper end of the tip mount sleeve 123 preferably has an inwardly tapered end face to assist in the insertion of the plunger clamping mechanism components into the hole in the tip mount sleeve 123. The lower end of the tip mount sleeve 123 preferably has a tapered end face on the outside to assist in inserting the lower end of the tip mount sleeve onto the pipette tip. The outer surface of each tip mount sleeve 123 is provided with a radially extending mechanism configured to form half of a snap-fit ​​connection with a correspondingly molded mechanism on the inner surface of the pipette tip. In this example, the radially extending mechanism is in the form of an annular groove 124 surrounding the tip mount sleeve 123.

[0032] The pipette tip clamping plate 125 has a number of openings 126 that extend axially through the thickness of the pipette tip clamping plate 125. The number and position of the openings 126 correspond to the number of openings 122 of the pipette tip mounting plate 121. The pipette tip clamping plate 125 further comprises a number of pipette tip clamping members 127, each associated with one of a plurality of pipette tip mounts 123. In this example, the number of pipette tip clamping members 127 are provided in the form of a number of clamp sleeves 127 defined by the region of the pipette tip clamping plate 125, directly surrounding the openings 126 defined within the pipette tip clamping plate 125. Each clamp sleeve 127 has a clamping region 128 having an inner diameter larger than the outer diameter of its respective tip mount sleeve. Thus, as shown in Figure 7, when the pipette tip clamping mechanism is engaged, a small gap is provided between the outer surface of the tip mount sleeve 123 and the inner surface of the clamping region 128.

[0033] Each clamp sleeve may have a substantially constant inner diameter. Alternatively, each clamp sleeve may have regions with different inner diameters, as shown in Figure 7. In the example, each clamp sleeve 127 has a narrow region 129A towards its upper end and a tapered region 129B at its bottom end. The inner diameter of the clamp sleeve 127 decreases in the tapered region 129B from the lowest tip to the clamping region 128. This configuration allows one or more pipette tips to be semi-locked in the pipette tip clamping plate 125 by positioning the tapered region 129B of the clamp sleeve 127 adjacent to a recess 124 on the outer surface of the tip mounting sleeve 123. This can facilitate the picking of a portion of multiple tips from the tip box. Once the picked tip is lifted above the multiple unpicked tips, the picked tip can then be clamped in place by moving the pipette tip clamping plate 125 to the clamping position. A small gap may be provided between the narrow area 129A of the clamp sleeve 127 and the outer surface of the tip mount 123. This can help minimize the force required to move the tip clamping plate 125 axially and facilitate the smooth operation of the pipette tip clamping mechanism.

[0034] As is most commonly seen in Figures 2 to 4, the pipette tip tightening drive mechanism 130 comprises a rotary actuator 131 and a screw shaft 132 operably connected to the output shaft of the rotary actuator 131. The rotary actuator 131 is mounted on a tip motor support plate 135, which is fixed in association with 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 portion 103. The tip motor support plate 135 is positioned above an expansion tab 133, which is fixed in association with the pipette tip tightening plate. The expansion tab 133 has a screw opening 133A through which the screw shaft 132 extends. The pipette tip tightening mechanism 130 further comprises a plurality of guide rods 134 connecting the pipette tip mounting plate 121 and the pipette tip tightening plate 125. In the illustrated embodiment, the guide rod 134 is fixed in association with the pipette tip mounting plate 121, each extending axially through the corresponding opening 137 in the pipette tip clamping plate 125. Naturally, it will be understood that the guide rod may be evenly fixed in association with the pipette tip clamping plate and extend through openings in the pipette tip mounting plate or any other part of the pipette operating head fixed in association with the pipette tip mounting plate.

[0035] When the rotary actuator 131 is operated, the screw shaft 132 rotates within the screw opening 133A, moving the expansion tab 133 toward or away from the tip motor support plate 135, thereby moving the pipette tip clamping plate 125 axially toward or away from the pipette tip mounting plate 121. The direction of movement is determined by the direction of rotation 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.

[0036] As best seen in Figures 5 and 8-11, the plunger clamping mechanism 140 comprises a plunger mounting plate 141, a plunger clamping plate 145 positioned on the plunger mounting plate 141, and a plunger clamping drive mechanism 150 operable to cause relative movement between the plunger mounting plate 141 and the plunger clamping plate 145. The plunger clamping mechanism 140 further comprises a plunger clamp motor mount 155 positioned on both the plunger mounting plate 141 and the plunger clamping plate 145. The actuator motor of the plunger clamping drive mechanism 150 is supported on the plunger clamp motor mount 155. The plunger mounting plate 141 and the plunger clamp motor mount 155 are fixed in relation to each other. In this example, the plunger mounting plate 141 and the plunger clamp motor mount 155 are provided as separate parts that are joined together to facilitate manufacturing and assembly. In other examples, the plunger mounting plate 141 and the plunger clamp motor mount 155 may be supplied 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, and to selectively engage the plunger clamping mechanism 140.

[0037] As best seen in Figures 8 and 9, the plunger mounting plate 141 has a number of openings 142 that extend axially through the thickness of the plunger mounting plate 141. Fixed within each opening 142, plunger mounts 143 extend downward axially from the plate 141 and are configured to connect with one of the plungers during use. Each plunger mount 143 is in the form of a tubular plunger mount sleeve held in one of the number of openings 142. In this example, each plunger mount 143 has an outer diameter larger than the diameter of the opening 142 and has a shoulder that abuts against the lower surface of the plunger mount plate 141. The shoulder helps to set the height of the plunger mount sleeve 143 when it is first inserted into the opening 142 in the plunger mount plate 141. The lower end of the tip mount sleeve 143 preferably has an inwardly tapered end face to assist in inserting the plunger into the hole of the plunger mount sleeve 143. Each plunger mount sleeve 143 is provided with a radially extending mechanism on its inner surface, configured to form half of a snap-fit ​​connection with a mechanism molded to correspond to the outer surface of the plunger. In this example, the radially extending mechanism takes the form of an annular recess 144 on the inner surface of the plunger mount sleeve 143 toward the lower end.

[0038] The plunger clamping plate 145 has a number of recesses or openings 146 that extend axially. The number and positions of the openings 146 of the plunger clamping plate 145 correspond to the number of openings 142 of the plunger mounting plate 141. The number of openings 146 of the plunger clamping plate 145 may also correspond to the number of openings 122 and 126 of the pipette tip clamping mechanism. The plunger clamping plate 145 further comprises a number of plunger clamping members 147, each associated with one of a plurality of plunger mounts 143. The number of plunger clamping members are provided in the form of a number of clamping rods 147 that extend axially from the plunger clamping plate 145 and into holes defined within the plunger mount sleeves 143. Each clamping rod 147 has an expanding head 148 at its lower end that extends from a narrower neck region 149A. The expanding head 148 has an outer diameter less than the inner diameter of the plunger mount sleeve 143. In this way, when the plunger clamping mechanism is engaged, a small gap is provided between the outer surface of the expanding head 148 and the inner surface of the plunger mount sleeve 143. The neck 149A has an outer diameter less than the outer diameter of the expanding head 148. Preferably, each clamping rod 147 also has a spindle 149B having an outer diameter substantially the same as the inner diameter of the area of ​​the plunger mount sleeve 143 in which it is located. As the plunger clamping plate 145 moves axially up and down relative to the plunger mount plate 141, the spindle 149B moves axially along the hole in the plunger mount 143.

[0039] As best seen in Figure 13, the plunger clamping drive mechanism 150 comprises a rotary actuator 151 and a screw shaft 152 operably connected to the output shaft of the rotary actuator 151. The rotary actuator 151 is mounted on a plunger clamp motor mount 155 and is therefore fixed in association with the plunger mounting plate 141. The rotary actuator 151 is positioned above an opening 153 in the plunger clamping plate 145, which has a screw opening 153A, and the screw shaft 152 extends through the screw opening 153A. The plunger clamping mechanism 150 further comprises a plurality of guide rods 154 that operably connect the plunger mounting plate 141 and the plunger clamping plate 145. In the illustrated embodiment, the guide rods 154 are fixed in association with the plunger clamping plate 145 and each extends axially into a corresponding hole in a cylindrical housing 157 extending from the lower surface of the plunger clamp motor mount 155. Naturally, it will be understood that the guide rod may extend through an opening in the plunger clamping plate 145 or any other part of the pipette operating head that is evenly fixed in relation to the plunger mounting plate 141 and fixed in relation to the plunger clamping plate 145.

[0040] When the rotary actuator 151 is operated, the screw shaft 152 rotates within the screw opening 153A, moving 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 direction of rotation of the actuator 151. This can be seen by looking at Figures 10 and 11, in which the plunger mounting plate 141 is omitted for clarity. In Figure 10, the guide rod 154 is extended from the cylindrical housing 157 so that the plunger clamping plate 145 and its support plate 156 are in a low position away from the lower surface of the plunger clamp motor mount 155 and close to the upper surface of the plunger mounting plate (not shown in Figures 10 and 11). This is the clamping position. In Figure 11, the guide rod 154 is retracted into the cylindrical housing 157 so that the plunger clamping plate 145 and its support plate 156 are away from the plunger mounting plate 141 and move axially toward the plunger clamp motor mount plate 155. This is the released 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 state, where the plunger is clamped in the appropriate position, and the released or "released" position or state, where the plunger is connected axially to the plunger mount or detached from the plunger mount. The plunger tightening mechanism 140 may be configured to move beyond the tightening position to the plunger mounting plate 141, reaching a removal state.In this position, the enlarged head 148 of the clamping rod 147 is axially aligned with a radially extending mechanism on the inner surface of the plunger mounting sleeve 143, which is instead aligned with the narrower neck portion 149A of the clamping rod. This allows the top of the plunger, i.e., the plunger connector portion, to bend inward. Further downward movement of the clamping plate 145 and the clamping rod 147 pushes the plunger downward, releasing 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 using the plunger clamping drive mechanism presses the plunger against one or more inner surfaces of the pipette tip, for example, the area around the opening at the distal end of the pipette tip, pushing the pipette tip out of the tip clamping mechanism. This removes the entire pipette assembly from the pipette operating head. Alternatively, a direct-drive actuator 160 may be used to move the clamping rod and plunger together downward, pressing them against the pipette, thereby removing the pipette tip from the device. In this removal mode, the plunger may remain in the device after the pipette tip has been removed.

[0041] Figures 12 and 13 show the direct-drive actuator 160 in more detail. The direct-drive actuator 160 comprises an actuator motor 161 mounted on the top surface of the upper head chassis 102. The output shaft of the actuator motor 161 is coupled to a screw rod 162 connected to a ball screw actuator nut 163. The output shaft of the actuator 161 may be integral with the screw rod 162 or fixed to the screw rod 162. In the illustrated embodiment, the output shaft is coupled to the screw rod by a rotationally rigid coupling in the form of a bellows coupling 161A. The bellows coupling 161A allows relative axial movement between the output shaft and the screw shaft 162, but prevents, or substantially prevents, relative rotation between the two parts. The nut 163 is fixed to a ball screw mount 164, and the two move simultaneously. In the illustrated embodiment, the ball screw mount 164 is fixed to a plunger clamp motor mount 155 at the upper end of a plunger clamping mechanism 140. In other embodiments, the ball screw mount 164 may be integrated with the plunger clamp motor mount 155. The direct drive actuator 160 then extends between the head chassis 101 and the plunger clamping mechanism 140.

[0042] When the actuator motor 161 is operated, the entire plunger clamping mechanism 140 moves axially along the guide rod 165 toward or toward the pipette tip clamping mechanism 120, depending on the direction of rotation of the actuator motor 161. The guide rod 165 is not threaded. The plunger mounting plate 141 has a plurality of guide sleeves 166 (see Figure 8), through which the guide rod 165 extends. When the actuator motor 161 is operated, the guide sleeves 166 slide along the outer surface of the guide rod. In this way, the plunger clamped by the plunger clamping mechanism 140 can be abruptly accelerated toward the pipette tip through which the plunger extends, regardless of any limitations imposed by the operating speed of the clamping mechanism. This allows the device to be used in both non-contact dispensing mode (also known as jetting – liquid is dispensed from the pipette slightly away from the target so that the droplet leaves the tip before contact with the target) and contact dispensing mode (a droplet forms on the pipette tip and settles upon contact with the target). For non-contact dispensing, the liquid sample must travel at a sufficiently fast speed to leave the tip. The distance traveled by the plunger relative to the dispensing shot is short, for example, in the range of 1 mm or less. Consequently, a high level of acceleration / deceleration is required to reach the target velocity for non-contact dispensing. For example, a direct-drive configuration via a ball screw provides a higher level of acceleration / deceleration for heavier loads than a belt-driven system, thus enabling non-contact dispensing of small amounts of liquid sample. Furthermore, a direct-drive configuration can provide higher positional accuracy and reproducibility than an equivalent belt-drive mechanism. This can significantly impact dispensing performance.

[0043] Figures 14 to 17 show pipette 1010 for use with the pipette operating heads shown in Figures 2 to 13. Pipette 1010 comprises a pipette tip 1100 and a plunger 1200.

[0044] The pipette tip 1100 may be a receptacle that receives and / or contains a sample fluid or sample liquid. The pipette tip 1100 may be configured to be inserted into or into a container of sample liquid. The pipette tip 1100 has a proximal end 1101 and a distal end 1102, the proximal end 1101 and the distal end 1102 defining a longitudinal axis 1001 extending between them. The pipette tip 1100 has an opening 1108 at its distal end 1102, as shown in Figure 15. The opening 1108 is at the distal end 1102, specifically at the outermost distal point of the pipette tip 1100, and may be defined by the inner wall surface 1111 of the pipette tip 1100. The opening 1108 may be any suitable shape, for example, elliptical, oval, or circular. The pipette tip 1100 has a fluid cavity 1109 that extends at least partially from the opening 1108 to the proximal end 1101. The fluid cavity may be configured to receive and / or hold a fluid, such as an air gap or sample liquid. The fluid cavity 1109 may be substantially elongated. The fluid cavity may be defined by the inner wall surface of the pipette tip 1100. The 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 aligned with 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 completely hollow. The pipette tip 1100 may contain or consist of a polymer material. The pipette tip 100 may contain or consist of a homogeneous material. The pipette tip 100 may contain or consist of a translucent or transparent material.

[0045] The pipette tip 1100 may comprise a series of parts, each having a different function, distinctive features, and / or different shape or dimensions. The pipette tip 1100 may comprise one or more of the following: a tip connector portion 1103, a central portion 1104, a support portion 1105, a body portion 1106, and a bridging portion 1107, as shown, for example, in Figure 15. From the proximal end 1101 to the distal end 1102, the parts may be arranged in the order of tip connector portion 1103, central portion 1104, support portion 1105, body portion 1106, bridging portion 1107, and end portion 1110. The fluid cavity 1109 may extend through one, more, or all of the parts of the pipette tip 1100. The plunger 1200 may extend through one, more, or all of the parts of the pipette tip 1100.

[0046] The tip connector section 1103 is configured to be connected to a liquid processing system, for example, by a snap-fit ​​connection. The tip connector section 1103 may comprise a divided tubular wall 1120 that can be defined by a plurality of flexible segments 1121. The flexible segments 1121 may be configured to elastically deflect radially outward, and the outer diameter of the proximal end 1101 of the pipette tip 1100 may increase from a first outer diameter where the flexible segments are not deflected and the tip connector section is in a stationary state, to a second outer diameter where the flexible segments are deflected radially outward and the tip connector section is in an expanded state. In the described embodiment, the tip connector section 1103 comprises four axially extending slits or slots 1122 in the tubular wall 1120 that divide into four flexible segments 1121. The tip connector section 1103 is provided with any number of axially extending slits 1122, which may define any number of flexible segments 1121, such as two, three, four, five, or six. The configuration of the flexible segments 1121 and slots 1122 allows the tip connector section to be expanded without requiring a large force to be applied to it. This reduces the insertion force required to engage the tip connector section 1103 with the pipette operating head.

[0047] The tip connector portion 1103 may further include one or more radially extending mechanisms 1123 on its inner surface, thereby enabling a pipette tip to be connected to a pipette operating head. The radially extending mechanisms on the inner surface of the tip connector portion 1103 may include projections extending radially inward and / or recesses or grooves extending radially outward. The radially extending mechanisms may extend circumferentially. In the described embodiment, the radially extending mechanisms on the inner surface of the tip connector portion 1103 include a partial annular rib 1123 protruding from the inner surface of the tip connector portion 1103. Preferably, the second outer diameter to which the tip connector portion expands is greater than the first outer diameter by at least the radial range of the radially extending mechanism 1123. The rib 1123 preferably has an angled upper and lower surface, and along the upper and lower surfaces, the inner diameter of the tip connector portion gradually increases from the rib 1123 to the upper and lower tip connector portions of the rib 1123. The angle of the upper surface may be selected according to the desired insertion force. The angle of the lower surface may be selected according to the desired withdrawal force. The upper or lower surface may each have an angle of 10 to 80 degrees from the axial direction of the pipette tip, for example, 20 to 70 degrees from the axial direction of the pipette tip, 30 to 60 degrees from the axial direction of the pipette tip, or 40 to 50 degrees from the axial direction of the pipette tip.

[0048] The central portion 1104 may be configured to center the plunger 1200 within the pipette tip 1100. The central portion 1104 may have an inner surface that can be tapered or conical in shape. 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. One or more ribs may extend on the outer surface of the pipette tip, for example, axially along at least a portion of the length between the proximal end 1101 and the distal end 1102, as is most commonly seen in Figure 16. The body portion 1106 may be substantially cylindrical and / or elongated. The body portion 1106 may have a substantially uniform inner and / or outer diameter. The body portion 1106 may extend along at least half the length of the pipette tip 1100. The main body 1106 may have an inner and / or outer diameter larger than any diameter of the end portion 1110. The bridge portion 1107 may be configured to bridge the main body 1106 to the end portion 1110. The bridge portion 1107 may define a gradual transition or step between the main body 1106 and the end portion 1110. The bridge portion 1107 may be substantially tapered, conical, and / or domed.

[0049] The plunger 1200 has a proximal end 1201 and a distal end 1202 and extends along the longitudinal axis 1101. The plunger 1200 is configured to extend at least partially into the end 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 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 opening 1108 to aspirate fluid or dispense fluid from the pipette tip 1100. The plunger 1200 may have an outer end wall surface 1212 configured to align with the inner wall surface 1111 of the pipette tip end 1110. The plunger 1200 may contain a polymer material or be made of a polymer material. The plunger 1200 may contain a homogeneous material or be made of a homogeneous material.

[0050] The plunger 1200 may comprise a series of parts, each having a different function, distinctive features, and / or different shape or dimensions. The plunger 1200 may comprise one or more of the plunger connector section 1203, the central section 1204, the body section 1206, and the sealing section 1207. From the proximal end 1201 to the distal end 1202, the parts may be arranged in the order of connector section 1203, central section 1204, body section 1206, sealing section 1207, and end section 1210.

[0051] The plunger connector portion 1203 is configured to be connected to a liquid handling system, for example, by a snap-fit ​​connection. The plunger connector portion 1203 may be configured to be fully received within the tip connector portion 1103 of a pipette tip 100. The plunger connector portion 1203 may comprise a divided tubular wall 1220 that can be defined by a plurality of flexible segments 1221. The flexible segments 1221 may be configured to elastically deflect radially inward, reducing the inner diameter of the proximal end 1201 of the plunger 1200 from a first inner diameter where the flexible segments are not deflected and the plunger connector portion is in a stationary state, to a second inner diameter where the flexible segments are deflected radially inward and the plunger connector portion is in a pressed state. In the described embodiment, the plunger connector portion 1203 comprises three axially extending slits or slots 1222 in the tubular wall 1220 that divide into three flexible segments 1221. The plunger connector portion 1203 may have any appropriate number of axially extending slits 1222 and define any number of flexible segments 1221. The configuration of the flexible segments 1221 and slots 1222 allows the plunger connector portion to be pushed in without large pushing stress. The plunger connector portion 1203 may further have one or more radially extending mechanisms 1223 on its outer surface, thereby allowing the plunger to be coupled to the pipette operating head. The radially extending mechanisms on the outer surface of the plunger connector portion 1203 may have projections extending radially outward and / or recesses or grooves extending radially inward. The radially extending mechanisms may extend circumferentially. In the described embodiment, the radially extending mechanisms on the outer surface of the plunger connector portion 1203 include a forming head 1223 at the upper end of the plunger, the lower part of which is defined by an annular groove on the outer surface of the plunger connector portion 1203. Preferably, the second inner diameter to which the plunger connector portion narrows is smaller than the first inner diameter by at least the radial range of the radially extending mechanism 1223, i.e., by at least half the difference between the outer diameter of the molding head 1223 and the outer diameter of the narrowest part of the annular recess.

[0052] The plunger connector portion 1203 may further include an internal wall 1224 extending laterally from the inner surface of the plunger connector portion 1203. The internal wall 1224 may be located at the end of the flexible segment 1221. The internal wall 1224 may be located close to the main body portion 1206. The internal wall 1224 forms a limiting portion that crosses the hole in the plunger connector portion. This provides a surface that the head of the clamping rod can contact, allowing the pipette to be removed. The internal wall 1224 may extend across the entire width of the hole inside the plunger 1200, as shown in Figure 17. However, this is not necessarily required. It is sufficient for the internal wall 1224 to limit the size of the hole to less than the outer diameter of the head of the clamping rod.

[0053] The central portion 1204 may have an annular shoulder. The central portion 1204 may be substantially conical or dome-shaped. In the depicted embodiment, the central portion 1204 is a radially extending truncated cone-shaped shoulder. The central portion 1104 of the pipette tip 1100 is preferably configured to receive and engage with the central portion 1204 of the plunger 1200 and to center the plunger in a straight line. In the embodiment shown in Figure 14, its two central portions have corresponding geometric shapes. The body portion 1206 of the plunger 1200 may be configured to be received by 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, and optionally at least two-thirds of the length of the plunger 1200. The main body portion 1206 may have a diameter larger than the diameter of the end portion 1210. The sealing portion 1207 of the plunger 1200 may be configured to be received by 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 may form a liquid-tight seal within the pipette tip so that when the plunger 1200 is placed inside the pipette tip 1100, fluid does not flow from the proximal side of the sealing portion 1207 to the distal side of the sealing portion 1207. The sealing portion 1207 may be at least partially flexible. The sealing portion 1207 may be configured to bridge the main body portion 1206 to the end portion 1210. The sealing portion 1207 may define a step between the main body portion 1207 and the end portion 1210. The sealing portion 1207 may be substantially tapered, conical, and / or domed. The end 1210 of the plunger 1200 may be configured to be received by the end 1110 of the pipette tip 1100. The end 1210 may have a smaller diameter than the sealing portion 1207 and / or the body portion 1206.

[0054] Referring to Figures 18 to 22, the method of connecting pipette 1010 to pipette operating head 100 according to the present invention is described below. Although the figures relating to the following description show only a single pipette, it will be understood that one or more of the connection, aspiration, dispensing, and withdrawal operations described can be applied to multiple pipettes simultaneously. For example, if the pipette operating head has 384 mounts, the following description may be applied to the simultaneous connection of 384 pipettes, or any subset thereof.

[0055] In Figure 18, both the pipette tip clamping mechanism 120 and the plunger clamping mechanism 140 are in the released state. When the pipette tip clamping mechanism 120 is released, the pipette tip clamping plate 125 is in its uppermost position relative to the lower surface of the pipette tip mounting plate 121. Importantly, in this position, the clamping area of ​​the tip clamp sleeve is axially offset from the annular groove around the outer surface of the tip mount sleeve. When the plunger clamping mechanism 140 is released, as shown, the plunger clamping plate 145 is in its uppermost position, and the expanding head 148 of the plunger clamping rod 147 is axially offset from the annular recess on the inner surface of each plunger mount sleeve. Subsequently, the entire pipette operating head 100 is moved axially to a number of pipettes 1010 using a pipette head Z motor (not shown) so that the tip mount sleeve is received within the tip connector portion of the pipette tip 1100. While the tip mount sleeve 123 is inserted into the proximal end of each pipette tip 1100, the annular rib 1123 of each pipette tip 1100 rides up onto the outer surface of the tip mount sleeve 123, deflecting the tip connector portion of each tip outward to its expanded position. Once the annular rib 1123 is received into the annular groove 124, as shown in Figure 18, the flexible segment returns to an undefended or partially deflected state. In this position, the tip connector portion is stationary, and each pipette tip 1100 is coupled to its respective pipette tip mount sleeve 123 by a snap-fit ​​connection. This is step 1.

[0056] Step 2 is described with reference to Figure 19. In Step 2, the pipette tip clamping mechanism 120 is engaged by lowering the pipette tip clamping plate 125 and moving it away from the pipette tip mounting plate, as shown in Figure 19. This causes the tip clamping sleeve 127 to extend around the tip connector portion 1103 of each pipette tip 1100, so that the clamping area of ​​each tip clamping sleeve is adjacent to the snap-fit ​​connection between each pipette tip 1100 and its respective tip mounting sleeve 123. The inner diameter of the clamping area 128 is less than the expanded diameter of the tip connector portion 1103 and may be substantially the same as, for example, the unexpanded outer diameter or the "first" outer diameter of the tip connector portion. This configuration prevents the tip connector portion 1103 from fully expanding and thus prevents the radially extending mechanism 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 "tightened" in the correct position without requiring any large force to be applied to the tip connector portion of the pipette tip 1100. This reduces the force required to engage the pipette tip tightening mechanism.

[0057] Between steps 1 and 2, the pipette tip clamping mechanism may be optionally moved to a partially engaged “pre-locked” position between the released and engaged states, in which position the tapered region 129B of each clamp sleeve 127 is adjacent to a recess 124 on the outer surface of its respective tip mount sleeve 123. This allows the picked tip to be secured to the tip mount without interference between the pipette tip clamping plate and the unpicked tips, thus facilitating the picking of a portion of the numerous tips from the tip box. Once the picked tip is lifted over the unpicked tips by the pipette operating head, the picked tip can then be fully clamped in place by moving the pipette tip clamping plate 125 to the clamping position.

[0058] Step 3 is described with reference to Figure 20. In Step 3, the entire plunger clamping mechanism 140 is lowered using a direct-drive actuator. This causes the plunger mount sleeve 143 to contact the plunger connector portion 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 mount sleeve 143 to ride up onto the outer surface of the plunger connector portion, deflecting the plunger connector portion inward to a retracted or pushed-in position, and the forming head 1223 at the top of the plunger 1200 to be received in the recess 144 on the inner surface of the plunger mount sleeve 143. Once the forming head 1223 is received in the recess 144 on the inner surface of the plunger mount sleeve 143, as shown in Figure 20, the flexible segment 1221 of the plunger connector portion 1203 returns to an undefended or partially deflected state. In this position, the plunger connector is stationary, and each plunger 1200 is connected to its respective plunger mount sleeve 143 by a snap-fit ​​connection.

[0059] Step 4 is described with reference to Figure 21. In step 4, the plunger clamp plate 145 is moved axially toward the plunger mounting plate 141 by the plunger clamp drive mechanism until the head 148 of the plunger clamp rod is adjacent to the snap-fit ​​connection between the plunger and the plunger mounting sleeve. The outer diameter of the head 148 of each clamp rod is greater than the inner diameter of the plunger when it is retracted, or the “second inner diameter”. For example, the outer diameter of the head 148 of each clamp rod may be substantially the same as the inner diameter of the plunger when it is not deflected, or the “first” inner diameter. This configuration prevents the plunger connector from being fully retracted to the retracted position and thus prevents the molded head 1223 of the plunger 1200 from being released from the recess 144 on the inner surface of the plunger mounting sleeve 143. In this way, the plunger 1200 is “locked” or “tightened” in the appropriate position without requiring any large pushing force to be applied to the plunger connector. This reduces the force required to engage the plunger tightening mechanism.

[0060] To perform the aspiration operation, the pipette operating head 100 is moved to the desired position relative to the liquid sample using the pipette operating head Z motor. The plunger of each pipette is then lifted within its respective pipette tip using a direct drive actuator, as shown in Figure 22, moving the entire plunger clamping mechanism away from the pipette tip clamping mechanism and drawing the fluid into the pipette tip. Subsequently, by moving the plunger clamping mechanism in the opposite direction using the direct drive actuator, the fluid can be dispensed as desired.

[0061] Once the aspiration and dispensing operation is complete, the pipette or multiple pipettes can be removed as follows: First, each plunger is moved to its lowest end within the pipette tip, and the tip clamping mechanism 120 is released by moving the tip clamping plate 125 to the tip mounting plate 121, and by shifting the clamp sleeve 127 out of alignment with the snap-fit ​​connection between each pipette tip and its respective tip mount 123, and away from the outer surface of the pipette tip. Next, the plunger clamping plate 145 is moved beyond its engaged position towards the plunger mounting plate 141, causing the heads 148 of each clamping rod 147 to move out of alignment with the snap-fit ​​connections between each plunger 1200 and its respective plunger mount 143. Instead, the neck portions 149A of each clamping rod 147 are aligned with the snap-fit ​​connections, and the distal end faces of the clamping rod heads are brought into contact with the inner wall 1224 of the plunger connector portion 1203. Since the neck portions 149A of the clamping rod 147 have an outer diameter less than the second pressed-in inner diameter of the plunger connector portion 1203, the plunger connector portion is not restricted from deflecting inward to a pressed-in state when the clamping rod is in this position. Therefore, the continuous downward movement of the plunger clamping plate 145 releases the molding head 1223 of the plunger connector portion 1203 from the corresponding radially extending mechanism 144 of the plunger mount 143, and the plunger 1200 is removed from the pipette operating head. Further downward movement of the plunger clamping plate, and consequently the clamping rod and the plunger itself, presses the distal end of the plunger against the parts of the pipette tip in which they are located. In this way, the plunger and the plunger clamping mechanism can be used to release the pipette tip 1100 from the pipette tip mount 123, thereby removing the pipette 1010 from the pipette operating head.

[0062] While the present invention has been described above with reference to one or more preferred embodiments, it will be understood that various changes or modifications can be made without departing from the scope of the invention as defined in the appended claims.

[0063] The present invention may be described or defined according to the following sections.

[0064] 1. A pipette operating head for a liquid dispensing device, for use with a plurality of pipettes, each having a pipette tip and a plunger provided within the pipette tip, wherein the pipette operating head is A pipette tip coupling mechanism having multiple tip mounts for holding the pipette tips of multiple pipettes during use, A plunger coupling mechanism having multiple plunger mounts for holding the plungers of multiple pipettes during use Equipped with, (i) Each of the multiple tip mounts has a radially extending mechanism on its outer surface configured to form half of a snap-fit ​​connection, and the pipette tip connection mechanism is Multiple chip clamping members, each associated with one of multiple chip mounts, and each having a clamping area, A tip tightening drive mechanism comprising an actuator that can be operated to selectively engage the pipette tip tightening mechanism by causing relative movement between the tip mount and the tip tightening member in the axial direction, thereby moving the pipette tip tightening mechanism between a clamped position and a released position. It is a pipette tip tightening mechanism that further includes the following: The clamping area of ​​each tip clamping member is axially adjacent to the mechanism extending radially from the outer surface of the associated tip mount when the pipette tip clamping mechanism is in the clamped position, and / or is axially offset from the mechanism extending radially from the outer surface of the associated tip mount when the pipette tip clamping mechanism is in the released position. (ii) Each of the plunger mounts has a radially extending mechanism on its inner surface configured to form half of a snap-fit ​​connection, the plunger connection mechanism Multiple plunger clamping members, each associated with one of multiple plunger mounts, and each having a clamping area, A plunger clamping drive mechanism comprising an actuator that can be operated to selectively engage the plunger clamping mechanism by causing relative movement between the plunger mount and the plunger clamping member in the axial direction, thereby moving the plunger clamping mechanism between a clamped position and a released position. It is a plunger tightening mechanism further equipped with, A pipette operating head wherein the clamping area of ​​each plunger clamping member is axially adjacent to a mechanism extending radially on the inner surface of the associated plunger mount when the plunger clamping mechanism is in the clamped position, and the clamping area of ​​each plunger clamping member is axially offset from the mechanism extending radially on the inner surface of the associated plunger mount when the plunger clamping mechanism is in the released position.

[0065] 2. The pipette operating head as described in item 1, wherein the multiple tip clamping members comprise multiple sleeves, the multiple sleeves defining a clamping area when the pipette tip clamping mechanism is in the clamping position, and are coaxial with the multiple tip mounts and surround the multiple tip mounts.

[0066] 3. The pipette tip clamping mechanism comprises a pipette tip clamping plate, on which a plurality of tip clamping members are provided, and the pipette tip clamping plate is axially movable relative to a plurality of pipette tip mounts, for selectively engaging the pipette tip clamping mechanism, as described in item 2.

[0067] 4. A pipette operating head as described in item 3, wherein multiple sleeves are defined by openings defined in a pipette tip clamping plate.

[0068] 5. The mechanism extending radially from the outer surface of each of the multiple tip mounts is a circumferential groove, as described in any one of items 1 to 4.

[0069] 6. A pipette operating head according to any one of items 1 to 5, wherein the multiple plunger mounts comprise multiple axially extending sleeves, and the multiple plunger clamping members comprise clamping rods, the clamping rods defining a clamping area when the plunger clamping mechanism is engaged, and the multiple axially extending sleeves extend into the interior of the multiple axially extending sleeves.

[0070] 7. The pipette operating head according to item 6, wherein each of the multiple clamping rods has an expanded distal end connected to a narrower shaft portion, the expanded distal end defining a clamping area.

[0071] 8. A pipette for use with any one of the pipette operating heads described in item 1 to 7, A pipette tip having a distal end with a dispensing opening and a proximal end with a tip connector portion for connecting the pipette tip to the pipette tip connecting mechanism of a pipette operating head during use, A plunger having a distal end positioned inside the pipette tip and a proximal end having a hollow plunger connector portion for connecting the plunger to the plunger coupling mechanism of the pipette operating head during use. Equipped with, (i) The tip connector portion has a radially extending mechanism on its inner surface configured to form a snap-fit ​​connection with a radially extending mechanism on one outer surface of a plurality of pipette tip mounts, and the tip connector portion is configured to be elastically deflected radially outward from a stationary position having a first outer diameter to an extended position having a second outer diameter that is larger than the first outer diameter by at least the radial range of the radially extending mechanism of the tip connector portion, and / or (ii) A pipette wherein the plunger connector portion has a radially extending mechanism on its outer surface configured to form a snap-fit ​​connection with a radially extending mechanism on the inner surface of one of a plurality of plunger mounts, and the plunger connector portion is configured to be elastically deflected radially inward from a stationary position having a first inner diameter to a pushed-in position having a second inner diameter smaller than the first inner diameter by at least the radial range of the radially extending mechanism of the plunger connector portion.

[0072] 9. The pipette according to item 8, wherein the tip connector portion comprises a segmented tubular wall defined by a plurality of flexible segments configured to elastically deflect outward in the radial direction, thereby deflecting the tip connector portion from a stationary position to an extended position.

[0073] 10. The pipette according to item 8 or 9, wherein the radially extending mechanism on the inner surface of the tip connector portion comprises circumferential ribs protruding radially inward from the inner surface of the tip connector portion.

[0074] 11. The pipette according to any one of claims 8 to 10, wherein the plunger connector portion comprises a segmented tubular wall defined by a plurality of flexible segments configured to elastically deflect inward in the radial direction, thereby deflecting the plunger connector portion from a resting position to a pushed-in position.

[0075] 12. The pipette according to any one of items 8 to 11, wherein the mechanism extending radially from the outer surface of the plunger connector portion comprises a molded head portion directly adjacent to a circumferential groove extending radially outward to the inner surface of the plunger connector portion.

[0076] 13. A pipette operating head according to any one of claims 2 to 4, further comprising at least one pipette as described in any one of claims 8 to 12, wherein each clamping area of ​​a plurality of sleeves of a tip clamping mechanism has an inner diameter greater than or equal to a first outer diameter of the tip connector portion and less than a second outer diameter of the tip connector portion, and when the tip clamping mechanism is in the clamped position, the clamping areas prevent the tip connector portion from being deflected to the expanded position, thereby releasing the snap-fit ​​connection.

[0077] 14. A pipette operating head according to item 6 or 7, further comprising at least one pipette as described in any one of items 8 to 12, wherein each clamping area of ​​a plurality of axially extending clamping rods has an outer diameter less than or equal to the first inner diameter of the plunger connector portion and greater than the second inner diameter of the plunger connector portion, and when the plunger clamping mechanism is in the clamped position, the clamping area prevents the plunger connector portion from being deflected to the pushed-in position, thereby releasing the snap-fit ​​connection.

[0078] 15. A main unit having a microplate receiving area, A pipette operating head as described in any one of items 1 to 7, 13, or 14, which is positioned above the microplate receiving area. A liquid dispensing device equipped with the following features.

Claims

1. A pipette operating head for a liquid dispensing device, for use with a plurality of pipettes, each having a pipette tip and a plunger provided within the pipette tip, wherein the pipette operating head is A pipette tip coupling mechanism having multiple tip mounts for holding the pipette tips of the numerous pipettes during use, A plunger coupling mechanism having multiple plunger mounts for holding the plungers of the numerous pipettes during use Equipped with, Each of the plurality of plunger mounts has a radially extending mechanism on its inner surface configured to form half of a snap-fit ​​connection, and the plunger connection mechanism is A plurality of plunger clamping members, each associated with one of the plurality of plunger mounts, each having a clamping area, A plunger tightening drive mechanism comprising an actuator that can be operated to selectively engage the plunger tightening mechanism by causing relative movement between the plunger mount and the plunger tightening member in the axial direction and moving the plunger tightening mechanism between a clamped position and a released position, and It is a plunger tightening mechanism further equipped with, A pipette operating head wherein the plurality of plunger mounts comprises a plurality of axially extending sleeves, and the plurality of plunger clamping members comprises a plurality of axially extending clamping rods, the clamping rods defining the clamping area when the plunger clamping mechanism is engaged, extending into the plurality of axially extending sleeves, the clamping area of ​​each plunger clamping rod being axially adjacent to the radially extending mechanism on the inner surface of the associated plunger mount when the plunger clamping mechanism is in the clamp position, and the clamping area of ​​each plunger clamping rod being axially offset from the radially extending mechanism on the inner surface of the associated plunger mount when the plunger clamping mechanism is in the release position.

2. The pipette operating head according to claim 1, wherein each of the plurality of tightening rods has an extended distal end connected to a narrower shaft portion, and the extended distal end defines the tightening area.

3. Each of the plurality of tip mounts is provided with a radially extending mechanism on its outer surface configured to form half of a snap-fit ​​connection, and the pipette tip connection mechanism is A plurality of chip clamping members, each associated with one of the plurality of chip mounts, each having a clamping area, A tip tightening drive mechanism comprising an actuator that can be operated to selectively engage the pipette tip tightening mechanism by causing relative movement between the tip mount and the tip tightening member in the axial direction and moving the pipette tip tightening mechanism between a clamped position and a released position, and It is a pipette tip tightening mechanism that further includes the following: The pipette operating head according to claim 1, wherein the clamping area of ​​each tip clamping member is axially adjacent to the radially extending mechanism on the outer surface of the associated tip mount when the pipette tip clamping mechanism is in the clamp position, and the clamping area of ​​each tip clamping member is axially offset from the radially extending mechanism on the outer surface of the associated tip mount when the pipette tip clamping mechanism is in the release position.

4. The pipette operating head according to claim 3, wherein the plurality of tip clamping members comprises a plurality of sleeves, the plurality of sleeves define the clamping area when the pipette tip clamping mechanism is in the clamping position, are coaxial with the plurality of tip mounts, and surround the plurality of tip mounts.

5. The pipette tip tightening mechanism comprises a pipette tip tightening plate, the plurality of tip tightening members are provided on the pipette tip tightening plate, the pipette tip tightening plate is axially movable relative to the plurality of pipette tip mounts, and selectively engages the pipette tip tightening mechanism, as described in claim 4.

6. The pipette operating head according to claim 5, wherein the plurality of sleeves are defined by openings defined in the pipette tip clamping plate.

7. The pipette operating head according to claim 3, wherein the radially extending mechanism on the outer surface of each of the plurality of tip mounts is a circumferential groove.

8. A pipette operating head for a liquid dispensing device, for use with a plurality of pipettes, each having a pipette tip and a plunger provided within the pipette tip, wherein the pipette operating head is A plunger coupling mechanism having multiple plunger mounts for holding the plungers of the numerous pipettes during use A pipette tip coupling mechanism having a plurality of tip mounts for holding the pipette tips of the plurality of pipettes during use, wherein each of the plurality of tip mounts has a radially extending mechanism on its outer surface configured to form half of a snap-fit ​​coupling, and the pipette tip coupling mechanism is A plurality of chip clamping members, each associated with one of the plurality of chip mounts, each having a clamping area, A tip tightening drive mechanism comprising an actuator that can be operated to selectively engage the pipette tip tightening mechanism by causing relative movement between the tip mount and the tip tightening member in the axial direction and moving the pipette tip tightening mechanism between a clamped position and a released position, and A pipette tip tightening mechanism, a pipette tip coupling mechanism, and Equipped with, A pipette operating head comprising a plurality of tip clamping members, wherein the plurality of sleeves define the clamping area and are coaxial with the plurality of tip mounts, and the plurality of sleeves surround the plurality of tip mounts by the clamping area of ​​each of the plurality of sleeves which is axially adjacent to the radially extending mechanism on the outer surface of the associated tip mount when the pipette tip clamping mechanism is in the clamp position, and the clamping area of ​​each sleeve is axially offset from the radially extending mechanism on the outer surface of the associated tip mount when the pipette tip clamping mechanism is in the release position.

9. The pipette operating head according to claim 8, wherein the plurality of tip clamping members comprises a plurality of sleeves, the plurality of sleeves define the clamping area when the pipette tip clamping mechanism is in the clamping position, are coaxial with the plurality of tip mounts, and surround the plurality of tip mounts.

10. The pipette tip tightening mechanism comprises a pipette tip tightening plate, the plurality of tip tightening members are provided on the pipette tip tightening plate, the pipette tip tightening plate is axially movable relative to the plurality of pipette tip mounts, and selectively engages the pipette tip tightening mechanism, as described in claim 9.

11. The pipette operating head according to claim 10, wherein the plurality of sleeves are defined by openings defined in the pipette tip clamping plate.

12. The pipette operating head according to claim 8, wherein the radially extending mechanism on the outer surface of each of the plurality of tip mounts is a circumferential groove.

13. A pipette for use with the pipette operating head described in claim 1, A pipette tip having a distal end having a dispensing opening and a proximal end having a tip connector portion for connecting the pipette tip to the pipette tip connecting mechanism of the pipette operating head during use, A plunger having a distal end positioned inside the pipette tip and a proximal end having a hollow plunger connector portion for connecting the plunger to the plunger coupling mechanism of the pipette operating head during use. Equipped with, A pipette wherein the plunger connector portion has a radially extending mechanism on its outer surface configured to form half of a snap-fit ​​connection, and the plunger connector portion is configured to be elastically deflected radially inward from a stationary position having a first inner diameter to a push-in position having a second inner diameter smaller than the first inner diameter, by at least the radial range of the radially extending mechanism of the plunger connector portion.

14. The pipette according to claim 13, wherein the tip connector portion comprises a divided tubular wall defined by a plurality of flexible segments configured to elastically deflect outward in the radial direction, thereby deflecting the tip connector portion from the stationary position to the extended position.

15. The radially extending mechanism on the inner surface of the chip connector portion extends in the circumferential direction, as described in claim 13.

16. The pipette according to claim 15, wherein the radially extending mechanism on the inner surface of the tip connector portion comprises a circumferential rib protruding radially inward from the inner surface of the tip connector portion.

17. The pipette according to claim 13, wherein the plunger connector portion comprises a divided tubular wall defined by a plurality of flexible segments configured to elastically deflect inward in the radial direction, thereby deflecting the plunger connector portion from the resting position to the pushed-in position.

18. The radially extending mechanism on the outer surface of the plunger connector portion extends in the circumferential direction, as described in claim 13.

19. The pipette according to claim 18, wherein the radially extending mechanism on the outer surface of the plunger connector portion comprises a molded head portion directly adjacent to a circumferential groove extending radially outward toward the inner surface of the plunger connector portion.

20. A pipette operating head according to claim 1, further comprising at least one pipette according to claim 13, wherein the clamping region of each of the plurality of axially extending clamping rods has an outer diameter less than or equal to the first inner diameter of the plunger connector portion and greater than the second inner diameter of the plunger connector portion, and when the plunger clamping mechanism is in the clamp position, the clamping region prevents the plunger connector portion from being deflected to the push-in position, thereby releasing the snap-fit ​​connection.

21. A main unit having a microplate receiving area, A liquid dispensing apparatus comprising a pipette operating head according to claim 1, wherein the pipette operating head is positioned above the microplate receiving area.

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