Dosage means for sucking and dispensing a liquid

Abstract

A metering tool for aspirating and dispensing liquids in a removable pipette tip is disclosed. The metering tool includes an ejector element that, when activated, separates the pipette tip from the metering tool. The metering tool also includes a variable volume defined by a cylinder, a piston disposed within the cylinder, and a distal end of the cylinder. A metering motor is coupled to the piston such that the motor drives the piston along axis A-A within the cylinder, causing the piston to be driven in an aspiration direction away from the distal end of the cylinder (thereby increasing the variable volume) or in a dispensing direction toward the distal end of the cylinder (thereby decreasing the variable volume). When the piston moves to an activated position in the aspiration direction, the ejector element is activated.

Description

Technical Field

[0001] This disclosure relates to quantitative tools, liquid handling apparatuses including quantitative tools, quantitative systems, and quantitative methods for aspirating or dispensing samples. In particular, this disclosure relates to miniaturization of quantitative tools by using the same quantitative motor for aspirating and dispensing liquid from removable pipette tips and for separating the pipette tips from the quantitative tool after use. Furthermore, this disclosure relates to reducing the dead volume of quantitative tools. Background Technology

[0002] Automated liquid handling systems, often referred to as quantitative workstations, can perform sample volume transfers between various source and destination containers. In this disclosure, such sample volume transfer is accomplished via pipetting, where liquid samples are aspirated and dispensed into removable pipette tips by manipulating an air cushion within the quantitative instrument.

[0003] This type of air cushion pipette has an integrated air displacement device and at least one seat for the pipette tip. The displacement device is typically formed by a cylinder with a movable plunger (e.g., a piston) that is guided within it. The piston typically also acts as a seal and / or a sleeve bearing. If the pipette tip remains on the seat, it is connected in communication with the displacement device. The displacement device moves the air cushion so that liquid can be drawn (aspirated) into the pipette tip and dispensed (dispensed) through the tip opening. After use, the pipette tip can be detached from the seat and replaced with a new pipette tip.

[0004] Various industries require automated liquid handling systems for the general movement of samples between source and destination containers, as well as more precise pipetting systems for aspirating and dispensing samples. For example, in drug research and clinical diagnostics, several types of liquid handling systems are used to move samples from one container to another.

[0005] Different types of sample containers, particularly multi-unit containers, are known or can be defined for use with automated liquid handling devices. Preferably, the sample container holder is configured to hold at least one sample container element. Such container elements are typically compact, thus requiring machinery capable of operating in confined spaces. Specific examples of sample container element types are cryovials, Falcon containers (1.5 ml and 50 ml), glass containers and beakers, slides, or multiple containers such as microtiter plates (MTPs), deep-well plates (DWPs), cell culture plates, and PCR plates. Multiple containers can have multiple (2 to 10) individual containers. They can also have a variety (greater than 10), typically 12, 16, 24, 32, 48, 64, 96, 384, or 1536 individual containers. Compared to “standard” microtiter plates, DWPs have a greater plate height and container height, as well as a greater mass. According to the American National Standards Institute (ANSI) standards and the Society for Biomolecular Screening (SBS) recommendations, the dimensions (length x width x height) of a microtiter plate are 127.76 mm x 85.48 mm x 14.35 mm. Relevant standards for these standardized dimensions are, for example, ANSI / SBS 1-2004, ANSI / SBS 2-2004, ANSI / SBS 3-2004, and ANSI / SBS 4-2004. Sample container elements defined by these standards or another standard are referred to herein as “standard-”. This type or standard type may refer to sample container elements having the same structure, or it may refer to a group of sample container elements that are identical in at least one typical characteristic.

[0006] The maximum sample volume that a pipette or sample container can hold is typically 0.01 ml to 100 ml, particularly 10-100 μl, 100-500 μl, 0.5-5 ml, 5-25 ml, 25-50 ml, and 50-100 ml, depending on the type of pipette or sample container chosen.

[0007] Pipetting can be performed using quantitative tools or systems with a single pipetting channel. In some applications, quantitative tools and systems with 8, 12, or up to 96 or more pipetting channels are used and are still in use, for example, for processing samples in a rectangular grid arrangement.

[0008] This places requirements or limitations on the size and compactness of metering tools. Therefore, miniaturizing the components in metering tools is one way to meet these requirements.

[0009] As understood in this article, another or additional approach is to have a single component perform multiple functions. This saves on the cost of having multiple components in the system. Furthermore, if a component (such as a fixed-displacement motor) is bulky and generates heat, it is preferable to use as few such components as possible to reduce heat generation.

[0010] Furthermore, as discussed, pipetting is performed by manipulating an air cushion. For example, an air cushion exists to prevent the sample from coming into contact with the quantitative instrument, thus avoiding contamination. However, since air can be compressed and expanded, and its volume can change significantly with temperature variations, it is preferable to have an air cushion that is as small as possible. Typically, the portion of the air cushion larger than the actual dose required is called dead volume and is generally undesirable.

[0011] As discussed in this paper, there is a need for a quantitative tool that reduces the number of large volumes and heat-generating components while providing low dead volumes. Summary of the Invention

[0012] In a first aspect, a metering tool for aspirating and dispensing liquid in a removable pipette tip is disclosed. The metering tool includes an ejector element that, when activated, separates the pipette tip from the metering tool.

[0013] This dispensing tool includes a variable volume defined by a cylinder, a piston disposed within the cylinder, and a distal end of the cylinder. For example, the cylinder defines a cylinder channel in which the piston is slidably disposed opposite the distal end of the cylinder. Therefore, the variable volume changes as the piston moves within the channel.

[0014] The metering instrument also includes a metering motor coupled to the piston. The metering motor drives the piston along axis AA within the cylinder, such that the piston is driven in a suction direction dA away from the distal end of the cylinder (thereby increasing the variable volume) or in a distribution direction dD toward the distal end of the cylinder (thereby decreasing the variable volume). As understood herein, the metering motor is not necessarily directly coupled to the piston, but can be indirectly coupled, for example, through a drivetrain.

[0015] Furthermore, as will be discussed further herein, the quantitative tool according to the first aspect thus provides that the ejector element is activated when the piston moves to the activated position in the suction direction.

[0016] This provides a dosing tool that requires only one dosing motor to perform the dosing actions (i.e., aspiration and dispensing) and to eject the pipette tip after use. Specifically, dosing is performed by driving the piston back and forth along the aspiration and dispensing directions as needed.

[0017] Once dosing has been performed and the pipette tip is ready to be discarded, the piston moves to the activated position in the aspiration direction. By providing an activated position in the aspiration direction, for example, by moving the piston away from the distal end of the cylinder, dead volume can be reduced.

[0018] According to one embodiment of the present aspect, the metering tool includes a housing connected to or connectable to a support arm in a liquid handling apparatus, wherein a cylinder and a metering motor are fixed to the housing. This provides a frame of reference and structural support for the various components within the metering tool.

[0019] On the other hand, a metering tool is provided for aspirating and dispensing liquid in a removable pipette tip, wherein the metering tool includes an ejector element that, when activated, separates the pipette tip from the metering tool.

[0020] The metering tool includes a housing that is connected to or can be connected to a support arm in a liquid handling apparatus. A metering motor is fixed to the housing, and a slider is slidably disposed relative to the housing along axis AA between an active position and a reference position. A drive system is disposed in the metering tool, which connects the metering motor to the slider. The drive system can drive the slider to move along axis AA in the suction direction toward the active position, or in the opposite direction along axis AA in the dispensing direction toward the reference position.

[0021] Furthermore, the metering tool includes a cylinder fixed to the housing. The cylinder defines a channel extending between a proximal end and a distal end of the cylinder.

[0022] The piston is positioned within a channel in the cylinder. The piston is driven by a slider either towards the proximal end of the cylinder in the suction direction or towards the distal end of the cylinder in the distribution direction.

[0023] A coupling arrangement is provided for detachably coupling a pipette tip to a metering tool, wherein the coupling arrangement is located at the distal end of the cylinder. An ejector element is located at the coupling arrangement and is movable to an activation position for disengaging the pipette tip.

[0024] To guide the movement toward the ejector element in the suction direction, a motion deflection device is provided to transfer the motion from the slider in the suction direction to the motion in the distribution direction, so that the ejector element moves to the activated position.

[0025] In one embodiment, a pop-out push rod for transferring motion from the motion deflection device to the pop-out element can be disposed between the motion deflection device and the pop-out element. The pop-out push rod can be a separate element or integrated into the pop-out element or the motion deflection device.

[0026] This provides specific embodiments of the quantitative tools discussed herein, offering the same advantages as the quantitative tools of the first aspect.

[0027] Specifically, only one metering motor is needed to perform metering actions (i.e., aspiration and dispensing) and to eject the pipette tip after use. Metering is performed by driving the piston back and forth along the aspiration and dispensing directions as needed.

[0028] Similarly, once dosing has been performed and the pipette tip is ready to be discarded, the piston moves to the activated position in the aspiration direction. By providing an activated position in the aspiration direction, for example, by moving the piston away from the distal end of the cylinder, dead volume can be reduced.

[0029] As discussed in this paper, quantitative instruments can be arranged in different configurations, and the components of the quantitative instruments will be arranged in the corresponding positions with reference to each configuration.

[0030] In one configuration, the quantitative tool is in a reference configuration, where the elements and components of the quantitative tool are in their respective reference positions. In the reference configuration, the quantitative tool will typically have a pipette tip arranged on it, and it is the initial configuration for initiating the aspiration of a sample into the pipette tip.

[0031] In another configuration, the quantitative tool is in its maximum stroke configuration, where the elements and components of the quantitative tool are at their respective maximum stroke positions. The maximum stroke configuration of the quantitative tool is the configuration that allows the maximum amount of sample to be aspirated into the pipette tip.

[0032] In another configuration, the metering tool is in an activated configuration, where the elements and components of the metering tool are in their respective activated positions. An activated configuration of the metering tool is one in which the elements and components of the metering tool are positioned such that the pipette tip is ejected or detached from the metering tool. Attached Figure Description

[0033] Figure 1a A first embodiment of the quantitative tool as disclosed herein is shown. Figure 1b Pipette tips for use with quantitative instruments as disclosed herein are shown. Figure 2 A first embodiment of a quantitative instrument in a reference configuration is shown, wherein the elements of the quantitative instrument are in their respective reference positions. Figure 3 A first embodiment of a metering tool in its maximum stroke configuration is shown, wherein the elements of the metering tool are at their respective maximum stroke positions. Figure 4 A first embodiment of a dosing instrument in an activated configuration is shown, wherein the elements of the dosing instrument are in their respective activated positions, and Figure 5a and Figure 5bA second embodiment of a motion deflection device in a quantitative tool as disclosed herein is shown. Detailed Implementation

[0034] In one embodiment, a metering motor is coupled to a piston via a drive system, wherein the drive system includes a slider coupled to the piston, and the metering motor drives the slider in a suction or dispensing direction. The purpose of the drive system is to transmit force from the motor to the slider, and then to the piston coupled thereto.

[0035] In one embodiment, the slider may be disposed within the housing, allowing the slider to move relative to the housing.

[0036] For example, in a further or additional embodiment, the drivetrain also includes a lead screw driven by a fixed-motor motor, a lead screw nut for converting rotary motion into translational motion along the piston axis AA, wherein the lead screw nut is connected to a slider, and a piston rod is coupled to the slider, extending along the axis AA from the slider to a piston disposed in the cylinder. This effectively converts the rotary motion of the motor into linear motion of the slider and therefore the piston rod.

[0037] As understood herein, a number of components will be described by their positions relative to axis AA. In this context, it should be understood that, unless otherwise specified, they are not necessarily arranged on this axis, for example, coaxially. For instance, if a component extends or moves along axis AA, it may, for example, be parallel to axis AA.

[0038] In one embodiment, the distal end of the piston rod may provide a piston. The piston may be a single element or formed from several separate elements, such as a piston body and a piston seal. The piston may also be formed as part of the piston rod itself, so that the two elements are integrally molded.

[0039] In one embodiment, the slider may also extend laterally to axis AA between the lead screw and the piston rod.

[0040] For example, in a further embodiment, a first torque control engagement is provided to prevent the slider from moving laterally to axis AA. Providing this torque control engagement in the slider ensures that the piston moves along axis AA and avoids deformation or any undesirable movement that could lead to incorrect suction or dispensing action.

[0041] In one embodiment, the first torque control engagement or the additional torque control engagement may include a through-hole extending through the slider along the axis CC, and the housing includes a slider cylinder extending along the axis CC, wherein the slider cylinder extends through the through-hole.

[0042] In one embodiment, a motion deflection device is provided for activating the ejection element by deflecting the motion in the suction direction toward the ejection element when the piston moves to the activation position in the suction direction.

[0043] As discussed herein, the purpose of a motion deflection device can also be considered as transferring motion in a first direction to a second direction opposite to the first direction. For example, changing the motion of the system in the suction direction to motion in the ejection direction. For example, motion can occur along axis AA in the first direction, whereby the motion deflection device can transfer the motion to a second direction along axis CC. Axis AA and axis CC can, for example, be parallel, and the first and second motions are in opposite directions as described.

[0044] For example, in one embodiment, the pop-out direction may be parallel to the distribution direction, such as along axis AA as discussed herein.

[0045] For example, in one embodiment, the motion deflection device may include an activation push rod that is movable between an intermediate position and an activated position, for example, along axis AA. When the piston moves to the activated position in the suction direction, the activation push rod moves from the intermediate position to the activated position in the suction direction.

[0046] In further or additional embodiments, the motion deflection device may include an ejector push rod engaging the ejector element, wherein the ejector push rod is movable between an intermediate position and an active position, for example, along the axis CC. When the piston moves to the active position in the suction direction, the ejector push rod moves from the intermediate position to the active position in the dispensing direction.

[0047] In one embodiment, the ejector rod can be slidably arranged along axis CC within the slider cylinder. This also makes it possible to provide a more compact device.

[0048] In one embodiment, the motion deflection device may include, for example, an activation push rod movable between an intermediate position and an activated position, such as along axis AA, wherein the activation push rod moves from the intermediate position to the activated position in the suction direction when the piston moves to the activated position. The motion deflection device may also include a ejection push rod engaging an ejection element, wherein the ejection push rod is movable between an intermediate position and an activated position, such as along axis CC, wherein the ejection push rod moves from the intermediate position to the activated position in the dispensing direction when the piston moves to the activated position in the suction direction.

[0049] A gear assembly may be provided for transferring and redirecting motion from the activating push rod in the suction direction to motion in the ejecting push rod in the distribution direction.

[0050] For example, such a gear assembly can be provided by a gear disposed between an activation push rod and a ejection push rod, an activation rack disposed on the activation push rod for example extending along axis AA, and an ejection rack disposed on the ejection push rod for example extending along axis CC.

[0051] Because the activating rack and ejector rack mesh with the gears, the direction of motion of the activating rack is redirected to the ejector rack via the gears. This provides one embodiment of a motion deflection device as discussed herein. The rack and gear mechanism described herein is similar to racks and pinions commonly known in mechanics.

[0052] In another embodiment, a lever assembly may be provided for transferring and redirecting motion from the activating push rod in the suction direction to motion in the ejection push rod in the distribution direction.

[0053] In one embodiment, the lever assembly may include a lever comprising a first flange and a second flange, wherein the lever is rotatably arranged on a hinge axis extending transversely to axis AA and between an activating push rod and a ejector push rod, wherein the first flange extends from the hinge axis toward the activating push rod, and the second flange extends from the hinge axis toward the ejector push rod. Thus, when the activating push rod moves from the intermediate position to the activated position, the activating push rod engages the first flange, and the second flange moves in the opposite direction to the first flange, engaging the ejector push rod and causing the ejector push rod to move from the intermediate position to the activated position in the dispensing direction.

[0054] In one embodiment, the ejector element includes at least a sleeve portion surrounding the distal end of the cylinder body, wherein the sleeve portion is slidable relative to the cylinder body along axis AA.

[0055] Detailed description of the attached figures In the following, specific embodiments will be discussed in more detail with respect to the accompanying drawings. Reference numerals are indicated in XYY format, where X indicates an embodiment and YY indicates an element in that embodiment. Thus, similar elements or features are indicated by similar YY annotations. For example, as discussed below, the quantitative instrument of the first embodiment is referred to as 100, while the quantitative instrument of the second embodiment is referred to as 200.

[0056] Furthermore, in relevant cases, references to the proximal or distal end of an element will be used to indicate orientation and extent. In a metering instrument, the distal end of an element will be the end of the element closest to the pipette tip when the tip is positioned on the instrument, while the proximal end will therefore be the furthest end from the pipette tip. When referring to the accompanying drawings, the proximal end will be indicated by the part number followed by an apostrophe, i.e., XYY'. The distal end will be indicated by the part number followed by two apostrophes, i.e., XYY''. In operation, the proximal end of an element will typically be the upward-facing portion of the element, while the distal end will be the downward-facing portion.

[0057] The first embodiment of the quantitative tool 100 is in Figure 1a , Figure 2 , Figure 3 and Figure 4 As shown in the figure, and the pipette tip 111 used for this quantitative tool is in Figure 1b As shown in the figure. The metering tool includes a housing 101, on which the components and elements of the metering tool are arranged in a fixed manner or slidably or movably relative to it. The housing is shown as a single piece, but would typically consist of a number of components fastened together by fastening elements such as screws. Although the housing is preferably formed of one piece or as few pieces as possible, manufacturing and assembly considerations may require multiple components to be supplied separately and subsequently assembled to provide housing 101. However, one or more components forming the housing have in common that they form a support frame or structure for the different components of the metering tool, as discussed below.

[0058] The fixed-displacement motor 102 is fixedly arranged at the near end 101' of the housing, opposite to the cylinder 103, which is fixedly arranged at the far end of the housing.

[0059] The cylinder is fixed to the distal end 101'' of the housing at its proximal end 103'. The cylinder extends along a metering axis AA between the proximal end 103' and the distal end 103'' of the cylinder. The cylinder is hollow and defines a channel 104 extending along axis AA between the proximal and distal ends 103', 103'' of the cylinder 103.

[0060] The piston 105 is disposed in the channel 104 of the cylinder body and can slide along the axis AA in the suction direction dA toward the near end 103' of the cylinder body or in the distribution direction dD toward the far end 103'' of the cylinder body.

[0061] The metering motor 102 can rotate in a first direction and a second direction, such as clockwise and counterclockwise or vice versa. The metering motor 102 is coupled to the piston 105 via a piston drive system, such that when the metering motor rotates in the first direction, the piston slides in the suction direction dA, and when the metering motor rotates in the second direction, the piston slides in the dispensing direction dD.

[0062] The piston drive system consists of multiple components that engage with each other to convert the rotational force of the fixed-displacement motor into linear motion of the piston along axis AA.

[0063] The piston drive system includes a lead screw 106, which extends along the lead screw axis BB and is driven by a fixed-displacement motor 102, causing the lead screw to rotate around the lead screw axis BB. The lead screw axis BB is parallel to the axis AA.

[0064] The piston drive system also includes a slider 107. The slider extends transversely to the metering axis AA and the lead screw axis BB and intersects the two axes.

[0065] A lead screw nut 108 is disposed within the slider and coaxial with the lead screw axis BB, such that the lead screw extends through the lead screw nut and the slider. The lead screw 106 includes an external threaded surface 150 that engages with the internal threaded surface 151 of the lead screw nut 108. Therefore, when the quantitative motor rotates the lead screw, the external threaded surface of the lead screw engages with the internal threaded surface of the lead screw nut, converting the rotational motion of the quantitative motor into linear motion of the lead screw nut 108 along the lead screw axis BB and thus along the quantitative axis AA. Since the lead screw nut is arranged and fixed to the slider 107, the slider will also move along axes AA and BB.

[0066] The piston drive system also includes a piston rod 109 attached to the slider 107. The piston rod extends coaxially to the piston 105 along the metering axis AA. In the current embodiment, the piston and piston rod are separate elements, but can be formed as a single unit. A sealing O-ring 110 is arranged around the piston and engages with the side of the passage 104 of the cylinder 103 to provide an hermetically tight seal.

[0067] Therefore, it can be understood that the piston transmission system includes a lead screw 106, a lead screw nut 108, a slider 107, and a piston rod 109, which engage with each other to transmit the rotational motion of the quantitative motor 102 to the linear motion of the piston 105.

[0068] Therefore, during liquid handling, sample aspiration and dispensing are accomplished via pipette tips 111 coupled to the metering tool. The pipette tips are coupled to the metering tool via coupling heads 112. The coupling heads engage the interior of the pipette tips in a robust and sealed manner. The piston drive system can then move the piston as follows: Figure 2 The reference position shown places the quantitative instrument in a reference configuration. In this reference position, the piston moves as far as possible toward the distal end 103'' of the cylinder 103. Since the piston can move all the way toward the distal end of the cylinder, this effectively means that any dead volume within the cylinder is eliminated. The reference position of the piston will typically be the position to initiate the aspiration of the liquid sample into the pipette tip.

[0069] During suction, the piston drive system can move the piston toward the proximal end 103' of the cylinder 103. It can continue to move the piston to... Figure 3 The maximum stroke position shown places the pipette in its maximum stroke configuration. The piston will be in the maximum stroke position when the maximum volume that the pipette can aspirate is received in the pipette tip. Therefore, the piston can be positioned during aspiration and dispensing. Figure 2 Reference position and Figure 3Any position between the maximum stroke positions, depending on the amount of liquid to be aspirated and the amount of liquid to be dispensed.

[0070] Once liquid processing has been performed and the sample has been dispensed from the pipette tip, the pipette tip is ready to be removed from the metering tool. In the current embodiment, this is accomplished by an ejection element shaped as an ejection sleeve 113, which is arranged coaxially around the cylinder 103 along axis AA. The inner circumference of the ejection sleeve at its distal end 113'' is smaller than the outer circumference of the proximal end 111' of the pipette tip. Therefore, as the ejection sleeve moves toward the pipette tip in the ejection direction dE, as... Figure 4 As shown, the ejector sleeve engages the pipette tip and disengages the pipette tip from the coupling head 112 by applying sufficient force to overcome the coupling between the coupling head and the pipette tip. As will be understood, in this embodiment, the ejection direction dE is parallel to the axis AA and moves in the same direction as the dispensing direction dD.

[0071] In order to move the ejector sleeve, the metering motor 102 is coupled to the ejector sleeve 113 through the ejector drive system, so that when the metering motor rotates in the first direction, the ejector sleeve moves in the ejection direction dE, and when the metering motor rotates in the second direction, the ejector element moves in the opposite direction to the ejection direction.

[0072] The ejector drive system is formed by multiple components that engage with each other to convert the rotational force of the metering motor 102 into linear motion of the ejector sleeve 113 along axis AA.

[0073] The pop-out transmission system shares some components with the piston transmission system. In particular, the lead screw 106, lead screw nut 108, and slider 107 are also used in the pop-out transmission system.

[0074] The ejection drive system also includes an activation push rod 115, which is slidably arranged along axis AA in the suction direction dA. Figure 1a , Figure 2 and Figure 3 The middle position shown and Figure 4 The activation positions are shown. The distal end 115'' is engaged by the slider 107, thereby activating the push rod 115 by the slider 107 moving the slider and piston from the maximum stroke position of the slider and piston in the suction direction dA to the activation position.

[0075] When the activation push rod 115 moves to the activation position, the motion deflection device 116 is activated, changing the direction of motion from the aspiration direction dA to the ejection direction dE. The ejection push rod 117 extends along the ejection axis CC, which is parallel to axes AA and BB. The proximal end 117' of the ejection push rod is coupled to the motion deflection device, and the distal end 117'' of the ejection push rod is coupled to the ejection sleeve 113. Therefore, when the activation push rod moves to the activation position in the aspiration direction dA, the motion deflection device redirects the motion to the ejection direction dE via the ejection push rod, reaching the ejection sleeve, and then detaches the pipette tip from the metering tool as described above.

[0076] Therefore, it can be understood that the ejector drive system includes a lead screw 106, a lead screw nut 108, a slider 107, an activation push rod 115, a motion deflection device 116, and an ejector push rod 117, which engage with each other to convert the rotational motion of the quantitative motor into the linear motion of the ejector sleeve 113.

[0077] When the ejector sleeve engages the pipette tip, force builds up before the tip ejects. This force increases the current required to drive the metering motor. As the pipette tip separates, the opposing force on the ejector sleeve disappears, and the current required to drive the metering motor decreases. Therefore, by monitoring the current driving the metering motor, it is possible to determine when the tip has been ejected and when the metering tool can be moved back. Figure 3 The maximum travel position is shown.

[0078] Figure 1- Figure 4 The motion deflection device 116 in the illustrated embodiment includes a gear and rack assembly. A first rack 120 is disposed at the proximal end 115' of the activation push rod 115. A second rack 121 is disposed at the proximal end 117' of the ejection push rod 117. The teeth of the first and second racks are opposite to each other. The first and second racks mesh with a gear 122 disposed between the first and second racks. The gear 122 is arranged on and rotatable about a gear shaft 123. The gear shaft extends transversely to axis AA and perpendicularly to a plane containing axis AA and axis CC.

[0079] Therefore, when the activation push rod is moved to the activation position, as the first rack 121 moves in the suction direction, the gear 122 will rotate and engage the second rack, which will move the ejection push rod 117 in the ejection direction dE as discussed.

[0080] After the ejection action has been performed, i.e., the pipette tip has been separated from the dispensing tool, the slider and piston move away from the activated position in the dispensing direction dD. A first compression spring 125 is arranged around the activation push rod, and a second compression spring 126 is arranged around the ejection push rod. As the slider 107 moves away from the activated position in the dispensing direction, the first and second compression springs cause the ejection sleeve 113 to move in the opposite direction to the ejection direction dE. This allows a new pipette tip to be placed on the dispensing tool 100.

[0081] When slider 107 moves up and down via the rotation of lead screw 106, undesirable torque may be applied to slider, causing slider to have some lateral movement transverse to axis AA, rather than purely linear movement along axis AA. This lateral movement may twist piston rod and cause piston to move slightly up and down in cylinder, thus having an undesirable effect on the metering action.

[0082] Therefore, to reduce or even eliminate the effect of torque on the slider, a torque control engagement can be provided. Such a torque control engagement can be provided by a slider cylinder shaped as a hollow shaft 130, which is fixed to the housing and extends through the slider along axis CC. The slider will be able to slide along the hollow shaft along axis CC, but the hollow shaft will prevent the slider from moving laterally to axis CC, and thus also prevent movement laterally to axis AA.

[0083] Furthermore, to make the design of the metering tool more compact, the hollow shaft includes a channel through which the ejector push rod 117 extends from the motion deflection device 116 to the ejector sleeve 113. Therefore, the hollow shaft 130 and the ejector push rod 117 extend coaxially along axis CC.

[0084] Electronic circuit 140 is provided for controlling the metering tool during liquid handling.

[0085] The electronic circuitry includes a quantitative motor controller 141, which communicates with and controls the operation of the quantitative motor 102.

[0086] The electronic circuitry also includes a pressure sensor 142, which monitors the pressure of a variable-volume air cushion in the cylinder block passage 104. A pressure conduit 143 connects the cylinder block passage and the pressure sensor.

[0087] In addition, the electronic circuitry includes a communication module 144, which allows the metering tool to communicate with a liquid handling system (not shown). The communication module can be wired, providing fixed communication, or it can be wireless.

[0088] Furthermore, the metering tool 100 includes a limit switch provided by a magnet 131 extending from the slider 107 and a magnetic field sensor 133. Therefore, when the slider 107 moves close to the magnetic field sensor 133, the sensor will detect the magnet 131 and can determine when the slider and the metering tool are in a position similar to... Figure 2 The reference configuration shown.

[0089] The electronic circuitry includes a power control board (PCB) 145, which ensures electronic control of various components, such as a quantitative motor controller 141, a pressure sensor 142, a communication module 144, and a magnetic field sensor 133.

[0090] A second embodiment of the quantitative tool 200 is shown in part. Figure 5a (at the maximum stroke configuration of the quantitative tool) and Figure 5b In the middle (in the activated configuration of the quantitative tool), a second embodiment of the motion deflection device 216 is provided.

[0091] As described with respect to the first embodiment, an activation push rod 215 and a ejection push rod 217 are provided. A lever 250 is rotatably arranged about a lever axis 251. A first flange 252 of the lever extends from the lever axis and engages the proximal end 215' of the activation push rod 215. A second flange 253 extends from the lever axis in the opposite direction to the first flange. The second flange engages the proximal end 217' of the ejection push rod 217.

[0092] Therefore, when the activation push rod moves to the activation position in the aspiration direction dA (by slider 207), the lever 250 will rotate around the lever axis and push the ejection push rod in the ejection direction dE, thereby ejecting the sleeve (not shown) and ejecting the pipette tip.

[0093] A compression spring 225 is arranged around the activation push rod. When the slider 207 moves to the maximum stroke position in the distribution direction dD, this will cause the activation push rod to move away from the activation position.

[0094] Figure Labels Quantitative tools 100; 200 Pipette Tip 111 Casing 101 Quantitative motor 102 Cylinder block 103 Channel 104 Piston 105 106 lead screw Slider 107; 207 Screw nut 108 External thread surface 150 Internal thread 151 Piston rod 109; 209 Sealing O-ring 110 Coupler 112 Ejector Sleeve 113 Activate push rod 115; 215 Motion deflection device 116; 216 The push rod pops out at 117; 217. First rack 120 Second rack 121 Gear 122 Gear shaft 123 First compression spring 125; 225 Second compression spring 126 Hollow shaft 130; 230 Electronic Circuit 140 Quantitative motor controller 141 Pressure sensor 142 Pressure Pipeline 143 Communication Module 144 Magnet 131 Magnetic field sensor 133 Power control board (PCB) 145 Leverage 250 Lever shaft 251.

Claims

1. A metering tool (100; 200) for aspirating and dispensing liquid in a removable pipette tip (111), wherein the metering tool (100) includes an ejector element (113) that, when activated, separates the pipette tip (111) from the metering tool (100; 200), wherein the metering tool (100; 200) comprises: o Variable volume, which is defined by a cylinder (103), a piston (105) disposed in the cylinder (103), and the distal end of the cylinder (103''). A metering motor (102), coupled to a piston (105), drives the piston (105) to move along axis AA within the cylinder (103), such that the piston (105) is driven either in a suction direction dA away from the far end of the cylinder (103'') (thereby increasing the variable volume) or in a distribution direction dD toward the far end of the cylinder (103'') (thereby decreasing the variable volume), and When the piston (105) moves to the activated position in the suction direction, the ejector element (113) is activated.

2. The metering tool (100; 200) according to claim 1, wherein the metering tool (100) includes a housing (101) connected to or capable of being connected to a support arm in a liquid handling apparatus, and wherein a cylinder (103) and a metering motor (102) are fixed to the housing (101).

3. The metering tool (100; 200) according to claim 1 or 2, wherein the metering motor (102) is coupled to the piston (105) via a drive system, wherein the drive system includes a slider (107; 207) coupled to the piston (105), wherein the metering motor (102) drives the slider (107; 207) in the suction direction or the dispensing direction.

4. The quantitative tool (100; 200) according to claims 2 and 3, wherein the slider (107; 207) is disposed in the housing (101) such that the slider (107; 207) is movable relative to the housing (101).

5. The metering tool (100; 200) according to claim 3 or 4, wherein the transmission system further includes a lead screw (106) driven by a metering motor (102), a lead screw nut (108) for converting the rotary motion into translational motion along the piston axis AA, wherein the lead screw nut (108) is connected to a slider (107; 207), and a piston rod (109) is coupled to the slider (107; 207), and wherein the piston rod (109) extends along the axis AA from the slider (107; 207) to a piston (105) disposed in a cylinder (103).

6. The metering tool (100; 200) according to claim 5, wherein the distal end of the piston rod (109) provides a piston (105).

7. The metering tool (100; 200) according to claim 5 or 6, wherein the slider (107; 207) extends transversely to axis AA between the lead screw (106) and the piston rod (109).

8. The metering tool (100; 200) according to any one of claims 3 to 7, wherein at least a first torque control engagement is provided to prevent the slider (107; 207) from moving laterally to axis AA.

9. The metering tool (100; 200) according to claim 8, wherein the metering tool (100; 200) includes a housing (101) connected to or capable of being connected to a support arm in a liquid handling apparatus, wherein a slider (107; 207) is disposed in the housing (101) such that the slider (107; 207) is movable relative to the housing (101), and wherein the metering tool (100) further includes: The first torque control engagement or additional torque control engagement includes a through-hole extending through the slider (107; 207) along the axis CC, and the housing (101) includes a slider cylinder (130; 230) extending along the axis CC, wherein the slider cylinder (130; 230) extends through the through-hole of the slider (107; 207).

10. The metering tool (100; 200) according to any of the preceding claims, wherein a motion deflection device (116; 216) is provided for activating the ejection element (113) in the ejection direction by deflecting the motion in the suction direction toward the ejection element (113) when the piston (105) is moved to the activation position in the suction direction.

11. The quantitative tool (100; 200) according to claim 10, wherein the ejection direction is parallel to the dispensing direction.

12. The metering tool (100; 200) according to claim 10 or 11, wherein the motion deflection device (116; 216) includes an activation push rod (115; 215) movable between an intermediate position and an activated position, wherein the activation push rod (115; 215) moves from the intermediate position to the activated position in the suction direction when the piston (105) moves to the activated position in the suction direction.

13. The metering tool (100; 200) according to claim 10, 11 or 12, wherein the motion deflection device (116; 216) includes a pop-out push rod (117; 217) engaging the pop-out element (113), and wherein the pop-out push rod (117; 217) is movable between an intermediate position and an activated position, wherein when the piston (105) moves to the activated position in the suction direction, the pop-out push rod (117; 217) moves from the intermediate position to the activated position in the dispensing direction.

14. The metering tool (100; 200) according to the combination of claim 9 and claim 13, wherein the ejector push rod (117; 217) is slidably arranged along axis CC within the slider cylinder (130; 230).

15. The metering tool (100) according to claim 10 or 11, wherein the motion deflection device (116) comprises: • Activate push rod (115), which is movable between a neutral position and an activated position, wherein when the piston (105) moves to the activated position in the suction direction, the activation push rod (115) moves from the neutral position to the activated position in the suction direction. • An ejector push rod (117) engages the ejector element (113), wherein the ejector push rod (117) is movable between a neutral position and an activated position, wherein when the piston (105) moves to the activated position in the suction direction, the ejector push rod (117) moves from the neutral position to the activated position in the dispensing direction, and • A gear assembly for transferring and redirecting the motion from the activation push rod (115) in the suction direction to the motion in the ejection push rod (117) in the distribution direction.

16. The metering tool (100) of claim 15, wherein the gear assembly comprises: • Gear (122) is set between the activation push rod (115) and the ejection push rod (117). • An activation rack (120) is set on the activation push rod (115). • A pop-out rack (121) is set on the pop-out push rod (121), and The active rack (120) and the ejector rack (121) mesh with the gear (122).

17. The metering tool (200) according to claim 10 or 11, wherein the motion deflection device (216) comprises: • An activation push rod (215) is movable between a neutral position and an activated position, wherein when the piston moves to the activated position in the suction direction, the activation push rod (215) moves from the neutral position to the activated position in the suction direction. • An ejector push rod (217) engages the ejector element, wherein the ejector push rod (217) is movable between a neutral position and an activated position, wherein when the piston moves to the activated position in the suction direction, the ejector push rod (217) moves from the neutral position to the activated position in the dispensing direction, and • A lever assembly for transferring and redirecting the motion from the activation push rod (215) in the suction direction to the motion in the ejection push rod (217) in the distribution direction.

18. The metering tool (200) of claim 17, wherein the lever assembly comprises a lever (250) including a first flange (252) and a second flange (253), wherein the lever (250) is rotatably arranged on a hinge axis (251) extending transversely to axis AA and between an activation push rod (215) and a ejector push rod (217), wherein the first flange (252) extends from the hinge axis (251) toward the activation push rod (215), and the second flange (253) extends from the hinge axis (251) toward the ejector push rod (217), wherein when the activation push rod (215) moves from a central position to an activated position in the suction direction, the activation push rod (215) engages the first flange (252), and the second flange (253) moves in the opposite direction to the first flange (252), engaging the ejector push rod (217) and causing the ejector push rod (217) to move from a central position to an activated position in the dispensing direction.

19. The metering tool (100; 200) according to any of the preceding claims, wherein the ejector element (113) includes a sleeve portion at least around the distal end of the cylinder (103), and wherein the sleeve portion is slidable relative to the cylinder along axis AA.

20. A metering tool (100; 200) for aspirating and dispensing liquid in a removable pipette tip (111), wherein the metering tool (100; 200) includes an ejector element (113) that, when activated, separates the pipette tip (111) from the metering tool (100; 200), wherein the metering tool (100; 200) comprises: • Housing (101), which is connected to or can be connected to a support arm in a liquid handling apparatus, • A fixed-displacement motor (102), which is fixed to the housing. • A slider (107; 207) is slidably disposed relative to the housing (101) between the active position and the reference position along axis AA. • A drive system that connects a metering motor (102) to a slider (107; 207) for driving the slider (107; 207) to move along axis AA toward the activated position in the suction direction, or in the opposite direction along axis AA toward the reference position in the dispensing direction. • A cylinder (103) fixed to a housing (101) defining a channel (104) extending between a proximal end (103') and a distal end (103'') of the cylinder. • A piston (105) disposed in a channel (104) of the cylinder body, wherein the piston (105) is driven by a slider (107; 207) toward the proximal end (103') of the cylinder body in the suction direction or toward the distal end (103'') of the cylinder body in the distribution direction. • A coupling arrangement (112) for detachably coupling a pipette tip (111) to a metering tool (100; 200), wherein the coupling arrangement (112) is located at the distal end (103'') of the cylinder. • A pop-out element (113), which is disposed at the coupling arrangement (112) and is movable to an activation position for separating the pipette tip (111), • A motion deflection device (116; 216) for transferring motion from the slider (107; 207) in the suction direction to motion in the dispensing direction, so as to move the ejector element (103) to the activated position, and • A pop-out push rod (117; 217) is used to transfer motion from the motion deflection device (116; 216) to the pop-out element (103).

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