Pipette for liquid dispensing device

Abstract

A pipette head (100) for a liquid dispensing device (10) is provided for use with an array of removable pipettes (1010). The pipette head has a pipette body mounting assembly (120) for holding a pipette body (1100) of a removable pipette, a plunger mounting assembly (140) for holding a plunger (1200) of the removable pipette, and a dispensing drive actuator assembly (160) with a dispensing drive mechanism (162) for moving the plunger mounting assembly along a drive axis. The pipette head also includes a pipette body clamping mechanism (130) having a clamping drive mechanism (133), the clamping drive mechanism including a linear actuator (133) and a clamping drive linkage having at least one support (135) fixed to the clamping plate (125) and extending axially between the clamping plate and the actuator. An actuator axially moves the at least one mount to selectively engage the pipette body clamping mechanism.

Description

Technical Field

[0001] The present invention relates to a pipette head for a liquid dispensing device, which is used with a series of pipettes, each pipette having a pipette body or "pipette tip" and a plunger disposed in the pipette body. The present invention particularly relates to a pipette head having a pipette body mounting assembly for holding a pipette body, a plunger mounting assembly for holding a plunger, a pipette body clamping mechanism capable of firmly holding the pipette body, and a dispensing drive mechanism for driving relative movement between the plunger and the pipette body mounting assembly. Background Art

[0002] It is known to use pipettes to aspirate or dispense liquid samples.

[0003] It is also known that the pipette used has a plunger arranged in the pipette body. The typical pipette, which is called a "positive displacement" pipette, uses a plunger or piston to draw or dispense liquid by direct contact with the sample liquid or through a small air gap. During use, the pipette body and the plunger are mounted together on the pipetting head of the liquid dispensing device, which drives the plunger relative to the body to draw or dispense liquid from the hole at the far end of the pipette body. This pipette can be used in an automated machine to improve the accuracy and repeatability of the pipetting action. Once the pipetting action is completed, the pipette body and the plunger of the removable pipette can be disconnected from the pipetting head and replaced.

[0004] The inventors have discovered that there are several problems with the way pipettes are connected to known pipetting heads for liquid dispensing devices.

[0005] Therefore, there is a need for an improved pipetting tip. Summary of the invention

[0006] The first aspect of the present invention provides a pipette head for a liquid dispensing device, the liquid head is used with a pipette array, each pipette having a pipette body and a plunger arranged in the pipette body. The pipette head includes: a pipette head chassis; a pipette body mounting assembly for holding the pipette body; a plunger mounting assembly for holding the plunger; a dispensing drive actuator assembly, operable to move the plunger mounting assembly along a drive axis relative to the pipette body mounting assembly to perform a dispensing or aspiration operation, the dispensing drive actuator assembly including a dispensing drive motor and a dispensing drive mechanism, the dispensing drive motor is coupled to the plunger mounting assembly through the dispensing drive mechanism to drive the plunger mounting assembly to axially displace; and a pipette body clamping mechanism, operable to selectively clamp the pipette body of the pipette array to the pipette body mounting assembly. The pipette body clamping mechanism includes: a pipette body clamping plate positioned below the plunger mounting assembly; a plurality of pipette body clamping members on the pipette body clamping plate; and a pipette body clamping drive mechanism operable to selectively engage the pipette body clamping drive mechanism, the pipette body clamping drive mechanism having a linear actuator and a pipette body clamping drive linkage, the linear actuator being coupled to the pipette body clamping plate via the pipette body clamping drive linkage, wherein the pipette body clamping drive linkage includes at least one support, the at least one support being fixed relative to the pipette body clamping plate and extending axially between the pipette body clamping plate and the linear actuator, and wherein the linear actuator is configured to move the at least one support in an axial direction relative to the pipette head chassis to selectively engage the pipette body clamping mechanism.

[0007] By this arrangement, the linear actuator of the pipette body clamping mechanism can be positioned away from the pipette body clamping plate and does not interfere with other moving parts of the pipette head. This can improve the packaging of the internal components of the pipette head. This is in sharp contrast to the arrangement in which the pipette body clamp is operated by a motor fixed to one side of the pipette body clamping plate. This design can reduce the width of the pipette head and avoid interference between the actuator and parts or equipment placed on the platform below the pipette head. In addition, by providing at least one support between the linear actuator and the pipette body clamping plate, this arrangement allows the rotational drive of the pipette body clamping plate to be separated from the way of guiding or moving the pipette body clamping plate. It has been found that this arrangement can reduce the risk of misalignment or "deflection" of the clamping plate compared to an arrangement in which the rotational drive and guidance are provided by the same component (for example, an arrangement in which a pulley nut is rotatably connected to the clamping plate to move the clamping plate along a threaded rod).

[0008] The pipette head is configured to be used with an array of pipettes, each pipette having a pipette body and a plunger arranged in the pipette body. The pipette array is an array of removable pipettes, each pipette having a removable pipette body and a removable plunger. Therefore, the plunger mounting assembly is used to hold the removable plunger of the removable pipette array. This is in contrast to some known pipette heads, in which the plunger or "piston" remains fixed to the pipette head, and the removable pipette consists only of a removable pipette tip. Using a pipette with a removable plunger helps reduce the risk of cross-contamination of samples. Utilizing the present invention, the plunger and body or "tip" of the removable pipette can be quickly removed and replaced in a single operation or a small number of operations.

[0009] The pipette body mounting assembly is configured to hold, ie, connect and retain, a pipette body relative to the pipette head.The pipette body mounting assembly may be configured to hold a pipette body connector portion of a pipette body of each of the removable pipette array.

[0010] The plunger mounting assembly is configured to hold, ie, connect and retain, the plunger relative to the pipetting head.The plunger mounting assembly may be configured to hold a plunger connector portion of the plunger of each of the removable pipette array.

[0011] As used herein, the term "clamping" refers to an arrangement whereby the pipette body or plunger (or both) are mounted and locked in place to prevent accidental removal. This is in contrast to an arrangement where the pipette body or plunger is mounted without locking (e.g., using only an interference fit or snap connection so that the pipette body or plunger can be removed simply by pulling axially). The use of a clamping mechanism can also improve the accuracy of pipetting and dispensing operations by preventing small relative movements that may occur between the pipetting tip and the plunger or pipette body.

[0012] As used in this article, the term "support" refers to a spacer or other rigid component used to separate two components in an assembly. At least one support maintains the spacing or separation between the pipette body clamping plate and the linear actuator, and transmits the axial drive to the pipette body clamping plate. At least one support may include a single support. Preferably, at least one support includes a plurality of supports. The support may be connected to the central area of ​​the pipette body clamping plate. Preferably, a plurality of supports are connected to the periphery of the pipette body clamping plate. A plurality of supports may include two, three or more supports. A plurality of supports may be positioned symmetrically around the periphery of the pipette body clamping plate. A plurality of supports may include four supports. The four supports may each be connected to a corner of the pipette body clamping plate.

[0013] The at least one mount may have any suitable shape.The at least one mount may include at least one guide rod along which the plunger mounting assembly is slidably supported when the plunger mounting assembly is axially moved by the dispense drive actuator assembly.

[0014] The at least one guide rod may include a plurality of guide rods along which the plunger mounting assembly is slidably supported when the plunger mounting assembly is axially moved by the dispense drive actuator assembly. The plurality of supports may be a plurality of guide rods along which the plunger mounting assembly is slidably supported when the plunger mounting assembly is axially moved by the dispense drive actuator assembly.

[0015] By this arrangement, the at least one guide rod performs a dual function, transmitting the axial drive to a plurality of pipette body clamping members and providing a guide member along which the plunger mounting assembly is slidably supported. Therefore, there is no need to provide separate components to guide the movement of the plunger mounting assembly and transmit the axial drive to a plurality of clamping members. This frees up space in the pipette head, allowing the use of a larger diameter guide rod without increasing the size of the pipette head. This can reduce the amount of bending in the guide rod, thereby maintaining the parallel relationship between the moving plates to further improve the performance of the pipette head. For example, the diameter of each guide rod can be between 8mm and 14mm, such as 10mm or 12mm. In addition, by providing a single set of components to guide the movement of the plunger mounting assembly and transmit the axial drive force to the pipette body clamping member, the tolerance superposition between the various moving parts of the pipette head will be less. This can improve the ease of operation of the pipette head and reduce the risk of misalignment. The multiple guide rods can include two, three, four or more guide rods. The multiple guide rods can include four supports, each of which is connected to a corner of the pipette body clamping plate.

[0016] In some preferred embodiments, at least one support is slidably supported by the pipetting head chassis. This can further increase the rigidity of the moving parts and reduce the risk of misalignment. The pipetting head chassis may include one or more linear bearings or bushings, through which the at least one support is slidably supported by the pipetting head chassis. The pipetting head chassis may include multiple linear bearings or bushings, through which the at least one support is slidably supported by the pipetting head chassis. Multiple linear bearings can be spaced apart in the axial direction to slidably support the at least one support at multiple points along its length.

[0017] In some preferred embodiments, the linear actuator is located above the plunger mounting assembly. This can further move the linear actuator away from other moving parts inside the pipetting head. In such embodiments, at least one support extends axially from below the plunger mounting assembly to above the plunger mounting assembly.

[0018] The linear actuator may include any suitable actuator. For example, the linear actuator may include a solenoid or a pneumatic or hydraulic actuation mechanism. In some preferred embodiments, the linear actuator includes a pipette body clamping motor and a screw mechanism for converting the rotational motion of the pipette body clamping motor into an axial motion of at least one support.

[0019] The screw mechanism may be laterally offset from the dispensing drive mechanism. In such examples, the axial force provided by the screw mechanism to the at least one support is laterally offset from the dispensing drive mechanism. In some preferred embodiments, the screw mechanism is hollow and defines an axial bore through which the dispensing drive mechanism extends.

[0020] By co-locating the screw mechanism of the distribution drive mechanism and the pipette body clamping drive mechanism, this arrangement can provide a compact structure. Both the linear actuator and the distribution drive mechanism can be located in the plunger mounting assembly, that is, not extending beyond the edge of the plunger mounting assembly in the lateral direction. This is in contrast to the known mechanism using a transmission belt and a pulley, which is located around the outer edge of the pipette and the plunger mounting mechanism. In this "outer" mechanism, the size of the pipette head must usually be increased to accommodate the pulley. By providing this compact pipette body clamping drive mechanism, a large number of pipettes can be more easily accurately and reliably installed to the pipette head. Because the compact arrangement can be configured to, for example, keep 384 pipettes in a 16×24 matrix, this is particularly beneficial for liquid dispensing equipment used with a standard 384-well plate. This makes it possible to draw liquid from a traditional 384-well plate or dispense liquid into a 384-well plate in a single operation.

[0021] The distribution drive mechanism can extend through the axial hole, with a certain lateral offset from the axis of the screw mechanism. In some preferred embodiments, the distribution drive mechanism and the screw mechanism are concentric. As used in this article, the term "concentric" refers to that the distribution drive mechanism and the screw mechanism are aligned along a common axis and have a common center on a vertical plane along at least a portion of the length of the distribution drive mechanism. In other words, the distribution drive mechanism extends along a first axis, and the screw mechanism is configured to rotate around a second axis, wherein the first axis and the second axis are coaxial.

[0022] By arranging the dispensing drive mechanism and the screw mechanism concentrically, the dispensing drive mechanism and the screw mechanism move along the same axis. This ensures alignment of the forces applied by the dispensing drive mechanism and the pipette body clamping mechanism, and can further help maintain a parallel relationship between the movable parts of the pipette head to further promote smooth operation and reduce the risk of misalignment or deflection caused by uneven application of force across the width of the plunger mounting assembly and / or the pipette body clamping mechanism.

[0023] This arrangement also allows the screw mechanism to provide a single force to the at least one support. This is in contrast to an arrangement that uses a belt drive mechanism and pulleys to move the pipette body clamping plate along multiple threaded rods, and in that arrangement, the pulleys must be synchronized to ensure correct alignment. This arrangement allows the screw mechanism to be centrally located within the pipetting head so that a single force applied to the at least one support is applied centrally. This can further improve the ease of operation and further reduce the risk of misalignment of the pipette body clamping plate.

[0024] In some preferred embodiments, the screw mechanism includes a first sleeve and a second sleeve that are concentric. The first sleeve and the second sleeve can be coupled by a threaded connection. The second sleeve can be fixed relative to the at least one support. The pipette body clamping motor can be configured to rotate the first sleeve around the second sleeve to drive the relative axial movement between the first sleeve and the second sleeve through the threaded connection, thereby driving the axial movement of the at least one support.

[0025] One of the first sleeve and the second sleeve may be defined by a hole in the plate. One or both of the first sleeve and the second sleeve may be defined by a hollow shaft. Preferably, the first sleeve and the second sleeve are defined by a first hollow shaft and a second hollow shaft.

[0026] Preferably, the median diameter of the threaded connection is less than 40% of the width of the plunger mounting assembly, preferably less than 30%, 20%, 10% or 5% of the width of the plunger mounting assembly. For example, the median diameter of the threaded connection may be 10mm to 80mm, 20mm to 60mm or 30mm to 50mm.

[0027] In some preferred embodiments, the pipette body clamping motor is coupled to the screw mechanism via one or more gears. The screw mechanism can be coupled to a ring gear that is configured to be rotated by the pipette body clamping motor. In other examples, the pipette body clamping motor can be coupled to the screw mechanism by any suitable means, for example, by a toothed belt drive or by a worm drive.

[0028] In some preferred embodiments, the pipette body clamping motor is fixed relative to the pipette head chassis. The pipette body clamping motor can be fixed to the pipette head chassis. The pipette head chassis can include an upper head chassis component to which the pipette body clamping motor is connected. The pipette body clamping motor can be located near the distribution drive motor. It has been found that this arrangement provides a particularly compact arrangement in the pipette head.

[0029] The pipette body mounting assembly is configured to hold the pipette body in place relative to the pipette head. The pipette body clamping mechanism is configured to firmly clamp any pipette body present in the pipette body mounting assembly. The pipette body clamping mechanism works independently from the pipette body mounting assembly. The pipette body mounting assembly holds the pipette body, and the pipette body clamping mechanism ensures that the pipette body is firmly fixed to the pipette body mounting assembly. This is in contrast to the arrangement in which the pipette body is held in place by a single mechanism. For example, the arrangement in which the pipette body is arranged in a material box, and the material box is held in the appropriate position on the lower side of the pipette head by a single mechanism. In this arrangement, this mechanism can be considered as a mounting assembly, by which the pipette body is held relative to the pipette head. However, this arrangement does not have an operable clamping mechanism to selectively clamp the pipette body to the pipette body mounting assembly.

[0030] The pipette body mounting assembly may include a pipette body mounting plate having a plurality of pipette body mounting members, each pipette body mounting member being configured to couple with one of the pipette bodies during use. The pipette body mounting plate may be defined by a lower surface of a pipette head chassis. The pipette body clamping mechanism includes a pipette body clamping plate having a plurality of pipette body clamping members disposed on the pipette body clamping plate, each pipette body clamping member being associated with one of the plurality of pipette body mounting members.

[0031] The pipette body clamping plate is located below the pipette body mounting assembly. The pipette body clamping plate can be the lowest plate in the pipette head. As used herein, the terms "above", "upper", "low", "below" and "lowest" refer to the normal orientation of the pipette head during use. Multiple pipette body clamping members may include multiple sleeves that define a clamping area. Multiple pipette body clamping members may be coaxial with multiple pipette body mountings disposed on the pipette body mounting assembly. When the pipette body clamping members are engaged, the multiple pipette body clamping members may surround the multiple pipette body mountings. Multiple sleeves may be defined by one or more discrete components fixed to the pipette body clamping plate. In some preferred embodiments, the multiple sleeves are defined by holes in the pipette body clamping plate itself. Each of the multiple pipette body mountings may include a radially extending feature located on its outer surface, the radially extending feature being configured to form half of a snap-fit ​​connection. When the pipette body clamping mechanism is in the clamping position, the clamping region of each of the plurality of sleeves may be axially adjacent to a radially extending feature on an outer surface of its associated pipette body mount. When the pipette body clamping mechanism is in the releasing position, the clamping region of each of the plurality of sleeves may be axially offset from a radially extending feature on an outer surface of its associated pipette body mount.

[0032] The distribution drive actuator assembly can be a direct drive actuator assembly. In such an embodiment, the distribution drive mechanism is a direct drive mechanism. As used herein, the term "direct drive mechanism" refers to a drive mechanism by which the distribution drive motor is either directly coupled to the plunger mounting assembly or coupled to the plunger mounting assembly in a rotationally rigid coupling manner. Throughout the specification, the term "direct drive actuator" is used to refer to a direct coupling arrangement and an arrangement in which the motor is coupled to the plunger mounting assembly by a rotationally rigid coupling. The use of a direct drive actuator minimizes the rotational clearance between the plunger mounting assembly and the motor. This enables the movement of the plunger mounting assembly to be started and stopped quickly and accurately. This is in contrast to an indirect drive mechanism in which the motor is coupled to the plunger mounting assembly by one or more belts or chains. In a similar manner, the clamping drive mechanism directly couples the clamping motor to a plurality of clamping members so that the movement of the pipette clamping mechanism can be started and stopped quickly and accurately.

[0033] The dispensing drive motor may be a linear actuator configured to provide a translational input to the dispensing drive mechanism. Preferably, the dispensing drive motor is a rotary motor configured to provide a rotational input to the dispensing drive mechanism, and the dispensing drive mechanism is configured to convert the rotational input into axial movement of the plunger mounting assembly.

[0034] The dispensing drive mechanism may include a ball screw, through which the drive motor is coupled to the plunger mounting assembly to drive the plunger mounting assembly to move axially. The dispensing drive mechanism preferably includes a drive shaft extending along a drive axis and a ball screw, through which the drive shaft is coupled to the plunger mounting assembly.

[0035] It has been found that direct drive arrangements, such as via a ball screw, provide higher levels of heavy load acceleration / deceleration than belt drive systems, thereby enabling contactless dispensing of low volume liquid samples. In addition, direct drive arrangements provide greater positional accuracy and repeatability than an equivalent belt drive mechanism. This can have a significant impact on dispensing performance.

[0036] The drive actuator operates completely independently of the pipette body clamping mechanism. By providing an independently operated drive actuator for dispensing or aspiration operations, a wider range of plunger speeds can be achieved, enabling the pipette head to operate accurately in both contact dispensing mode and non-contact dispensing mode. This is in contrast to some known liquid handling devices in which the pipette body and plunger are coupled to a plate positioned along a set of common threaded rods and can only move relatively slowly relative to each other along the common threaded rods. Non-contact dispensing, also known as jetting, is characterized by liquid being dispensed from the pipette at a distance from the target so that the droplet separates from the end of the pipette body before contacting the target. Contact dispensing is characterized by droplets forming at the end of the pipette body and being deposited by contact with the target. When performing non-contact dispensing, the liquid sample must be detached from the end at a sufficiently high speed. The distance traveled by the plunger for dispensing jetting can be small, such as in the range of 1 mm or less. Therefore, in order to achieve the target speed for non-contact dispensing, a high level of acceleration / deceleration is required.

[0037] With an independently operated drive actuator, the plunger mounting assembly mechanism and any plunger mounted thereon can be moved relative to the pipette body mounting assembly to perform aspiration and dispensing operations independently of the pipette clamping mechanism. The distance traveled by the plunger for dispensing the jet can be very small, for example within a range of 1 mm or less. Therefore, in order to achieve the target speed of non-contact dispensing, a high level of acceleration / deceleration is required. The independently operated drive actuator can be configured to accelerate and decelerate the plunger mounting assembly at a sufficiently high rate so as to achieve non-contact dispensing and contact dispensing using the same mechanism.

[0038] The term "independent operation" refers to an arrangement in which the drive mechanism does not share any parts with the pipette clamping mechanism. This allows the drive mechanism to be set according to the acceleration and deceleration characteristics required for the dispensing and aspiration operations, rather than being set according to the required clamping characteristics, or a compromise between these characteristics. This is in direct contrast to arrangements in which the pipette body and plunger are mounted on a plate arranged along a common threaded rod, in which all drive mechanisms (including the drive mechanisms for the actuators controlling the dispensing operation) must operate with the same pitch. These arrangements may also require synchronization of the movement of the plates in order to perform the dispensing operation. This requires more complex controls to ensure accurate dispensing and prevent clogging.

[0039] The plunger mounting assembly may include a plunger clamping mechanism operable to clamp the plunger of the pipette array to the plunger mounting assembly, the plunger clamping mechanism including a plunger clamping plate, a plurality of plunger clamping members on the plunger clamping plate, and a plunger clamping drive mechanism operable to selectively engage with the plunger clamping mechanism, the plunger clamping mechanism having a linear actuator configured to drive relative axial movement between the plunger clamping plate and the plunger mounting assembly to selectively engage the plunger clamping mechanism.

[0040] The linear actuator may include any suitable actuator. For example, the linear actuator may include a solenoid or a pneumatic or hydraulic actuation mechanism. In some preferred embodiments, the linear actuator of the plunger clamping drive mechanism includes a plunger clamping motor and a screw mechanism for converting the rotary motion of the plunger clamping motor into the axial motion of the plunger clamping plate.

[0041] The screw mechanism of the plunger clamping drive mechanism may include a first sleeve and a second sleeve that are concentric. The first sleeve and the second sleeve may be coupled by a threaded connection. The second sleeve may be fixed relative to the plunger mounting assembly. The plunger clamping motor may be configured to rotate the first sleeve around the second sleeve to drive the axial movement of the plunger clamping plate.

[0042] Preferably, the mid-diameter of the threaded connection of the plunger clamping drive mechanism is less than 40% of the width of the plunger clamping plate, preferably less than 30%, 20%, 10% or 5% of the width of the plunger clamping plate. For example, the mid-diameter of the threaded connection can be 10mm to 80mm, 20mm to 60mm or 30mm to 50mm.

[0043] In some preferred embodiments, the screw mechanism of the plunger clamp drive mechanism is hollow and defines an axial bore in which a portion of the dispensing drive mechanism is accommodated. It has been found that this provides a particularly compact structure in which the overall height of the pipetting head can be reduced.

[0044] In some preferred embodiments, the dispensing drive mechanism includes a ball screw actuator nut that is at least partially received within an axial bore of a screw mechanism of the plunger clamp drive mechanism.

[0045] The dispensing drive mechanism may extend through the axial bore with a certain lateral offset from the axis of the screw mechanism. In some preferred embodiments, the dispensing drive mechanism and the screw mechanism of the plunger clamping drive mechanism are concentric.

[0046] By arranging the dispensing drive mechanism and the screw mechanism concentrically, the dispensing drive mechanism and the screw mechanism move along the same axis. This ensures alignment of the forces applied by the dispensing drive mechanism and the plunger clamping mechanism, and can further help maintain a parallel relationship between the movable components of the pipetting head to further promote smooth operation and reduce the risk of misalignment or deflection due to uneven application of force across the width of the plunger clamping mechanism. This arrangement allows the screw mechanism to be centrally located within the pipetting head so that the axial force applied to the plunger clamping plate is applied centrally. This can further improve the ease of operation and further reduce the risk of misalignment of the plunger clamping plate.

[0047] In some preferred embodiments, the plunger mounting assembly includes a plurality of plunger mountings, and wherein the plurality of plunger clamping members include a plurality of clamping rods, each clamping rod being coaxial with one of the plurality of plunger mountings and extending within the plunger mountings to limit inward movement of a plunger contained in the plunger mountings when the plunger clamping mechanism is engaged.

[0048] The plunger mounting assembly may further include a plunger mounting plate on which a plurality of plunger mounting members are disposed.

[0049] The plurality of plunger mounts may include a plurality of axially extending sleeves. Each of the plurality of axially extending sleeves may include a radially extending feature on an inner surface thereof, the radially extending feature being configured to form half of a snap-fit ​​connection. When the plunger clamping mechanism is in a clamped position, a clamping region of each of the plurality of clamping rods may be axially adjacent to the radially extending feature on the inner surface of its associated plunger mount, and when the plunger clamping mechanism is in a released position, a clamping region of each of the plurality of clamping rods may be axially offset from the radially extending feature on the inner surface of its associated plunger mount.

[0050] According to a second aspect of the present invention, there is provided a liquid dispensing device comprising: a body having a platform for receiving one or more microplates; and a pipetting head according to the first aspect, the pipetting head being located above the platform.

[0051] Although the platform is configured to receive one or more microplates, other laboratory equipment may be received on the platform instead of or in addition to microplates. For example, an array of one or more pipette bodies, well plates or microplate transfer devices, and an array of vials or sample tubes, liquid reservoirs, or any other laboratory equipment that may be used with a liquid dispensing device may be received on the platform.

[0052] Also disclosed is a pipette head for a liquid dispensing device, which is used with a removable pipette array, each removable pipette having a pipette body and a plunger disposed in the pipette body, the pipette head comprising: a pipette head chassis; a pipette body mounting assembly for holding the pipette body; a plunger mounting assembly for holding the plunger; a dispensing drive actuator assembly operable to move the plunger mounting assembly relative to the pipette body mounting assembly along a drive axis to perform a dispensing or aspiration operation, the dispensing drive actuator assembly comprising a dispensing drive motor and a dispensing drive mechanism, the dispensing drive motor being coupled to the plunger mounting assembly via the dispensing drive mechanism to drive its axial displacement; and a plunger clamping mechanism operable to clamp the plunger of the pipette array to the plunger mounting assembly. The plunger clamping mechanism includes: a plunger clamping plate; a plurality of plunger clamping members on the plunger clamping plate; and a plunger clamping drive mechanism operable to selectively engage the plunger clamping mechanism, the plunger clamping mechanism having a linear actuator configured to drive relative axial movement between the plunger clamping plate and the plunger mounting assembly to selectively engage the plunger clamping mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Further features and advantages of the present invention will be further described below, by way of example only, with reference to the accompanying drawings, in which:

[0054] Figure 1 is a front view of a liquid dispensing device having a pipetting head according to the present invention;

[0055] Figure 2 is a perspective view of a pipetting head according to the present invention;

[0056] Figure 3 yes Figure 2 A perspective view of a pipetting head with a top cover removed to show the components underneath;

[0057] Figure 4 yes Figure 2 An exploded perspective view of a head chassis of a pipetting head;

[0058] Figure 5 yes Figure 2 a cross-sectional view of a pipette head of wherein the upper head chassis assembly is omitted for clarity and wherein the pipette body mounting mechanism and the plunger mounting mechanism are shown;

[0059] Figure 6 yes Figure 3 A cross-sectional view of a pipette head showing the plates of the pipette body clamping mechanism and the plunger clamping mechanism;

[0060] Figure 7 yes Figure 5 an enlarged view of an upper portion of a cross-sectional view of;

[0061] Figure 8 yes Figure 2 An enlarged cross-sectional view of a pipette body mounting assembly and a pipette body clamping mechanism of a pipette head, showing a pipette body mounting sleeve;

[0062] Fig. 9 yes Figure 2 A cross-sectional view of a plunger mounting assembly and a plunger clamping mechanism of a pipetting head;

[0063] Fig.10 yes Figure 2 A cross-sectional view of a plunger clamping mechanism of a pipette head;

[0064] Fig.11 yes Figure 2 An enlarged cross-sectional view of a plate of a plunger mounting assembly and a plate of a plunger clamping mechanism of a pipetting head, showing the plunger mounting member and the clamping rod;

[0065] Fig.12 yes Figure 6 an enlarged view of a middle portion of a cross-sectional perspective view of the dispense drive actuator assembly;

[0066] Fig.13 is with Figure 1 A cross-sectional view of a pipette used with a liquid dispensing system;

[0067] Fig.14 yes Fig.13 A perspective view of a pipette body and a plunger of a pipette of , wherein the plunger has been removed from the pipette body;

[0068] Fig.15 yes Fig.13 An enlarged cross-sectional view of a pipette showing the pipette body connector portion and the plunger connector portion in more detail;

[0069] Fig.16 yes Fig.13 a perspective view of a pipette showing a pipette body mount and an associated pipette body clamp of a pipette body clamping mechanism; and

[0070] Figures 17 to 21 is an enlarged partial cross-sectional view of the pipette body and plunger mounting assembly and clamping mechanism at various stages of pipette connection. DETAILED DESCRIPTION

[0071] Figure 1A liquid dispensing device 10 is shown for use with an array of positive displacement pipettes 1010. The device 10 includes a body 12 having a microplate receiving area or platform 14 and a pipetting head 100, the body 12 having a microplate receiving area or platform 14, and the pipetting head 100 is located above the microplate receiving area 14. The microplate receiving area 14 has a substantially horizontal upper surface 16 arranged to receive a laboratory microplate. The receiving area 14 can be located on a height-adjustable support structure 18 that enables the height of the microplate receiving area 14 to be varied as desired. The receiving area 14 can be configured to hold a laboratory microplate in a fixed position. For example, the upper surface 16 of the receiving area 14 may include one or more recesses (not shown) that are arranged to receive the microplate and prevent the microplate from lateral translation relative to the receiving area 14. The device 10 will typically be positioned in a position to receive the microplate. Figure 1 Use in the orientation shown to hold the product in the wells of the microplate by gravity. Figure 1 The axis labeled Z in the figure represents the upward direction, and gravity acts in the opposite direction to hold the product in the wells of the microplate. Therefore, references to the upward and downward directions or the axial direction refer to the direction along which the product is moved. Figure 1 The axis marked Z in the figure is the axis of motion, while reference to the lateral or transverse direction refers to the Figure 1 The vertical direction or height also refers to the movement along the Figure 1 The pipetting head 100 is configured to hold a pipette array (as described below with respect to Figures 2 to 21 14) and can be moved relative to the platform 14 so that a pipette mounted on the pipetting head 100 is close to a microplate supported on the platform 14, thereby allowing liquid to be aspirated from or dispensed into the wells of the microplate.

[0072] Figure 2 1 is a perspective view of a pipetting head 100. The pipetting head includes a head chassis 101 having an upper head chassis component 102, a lower head chassis component 103, and a middle head chassis component 104 located between the upper head chassis component and the lower head chassis component, all of which are fixed together to form the body of the pipetting head 100. A top cover 105 can be removably mounted on the top surface of the upper head chassis component 102. The head chassis 101 is connected to the body of the device by a chassis support plate (not shown), which preferably enables the entire pipetting head 100 to be moved 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).

[0073] Figure 3 is a perspective view of the pipetting head 100 after removing the top cover, Figure 41 is an exploded view of the head chassis assembly of the pipette head 100. The upper head chassis component 102 provides support for the dispensing drive motor 161 and the pipette body clamping motor 132 of the dispensing drive actuator assembly 160 of the pipette head 100 on its top surface, which will be discussed in more detail below. The control circuit 106 for the operation of the pipette head is also fixed to the top surface of the upper head chassis component 102. When the top cover 105 is placed on the upper head chassis component 102, all components mounted on the top surface of the upper head chassis component 102 will be enclosed under the top cover 105. The middle head chassis component 104 includes an outer wall 107, which has a rectangular cross-sectional shape. The outer wall 107 includes a hole 110 at each of its four corners. Each hole 110 can include a linear bushing 115. The lower head chassis component 103 has an outer wall 111 that defines an inner cavity 112 and has a rectangular cross-sectional shape as the upper head chassis component 102 and the middle head chassis component 104. The outer wall 111 includes a hole 113 at each of its four corners. Each hole 113 may include a linear bushing 116.

[0074] The pipette head 100 also includes a pipette body mounting assembly 120 for holding the pipette bodies of the array of positive displacement pipette bodies during use. The pipette body mounting assembly 120 includes a pipette body mounting plate (on Figure 6 The pipette body mounting plate is formed by, integrated with, or otherwise secured to the underside of the lower head chassis member 103, as shown in the figure as feature 121. The upper head chassis member 102, the lower head chassis member 103, and the middle head chassis member 104 may be secured together using any suitable method, such as bolts and tie rods.

[0075] Figure 5 1 is a cross-sectional view of the pipette head 100, with the upper head chassis component and the middle head chassis component of the pipette head removed for clarity. The pipette head 100 also includes a plunger mounting assembly 140 for holding the plunger of the array of positive displacement pipette bodies during use. The pipette head 100 also includes a pipette body clamping mechanism 130 for firmly clamping the pipette body on the pipette body mounting assembly 120. In this embodiment, the pipette head 100 also includes a plunger clamping mechanism 150 for firmly clamping the plunger on the plunger mounting assembly 140. In other embodiments, the pipette head may include only one of the two pipette clamping mechanisms. The pipette head 100 also includes a dispensing drive actuator assembly 160, which is operable to move the plunger mounting assembly 140 in an axial direction relative to the pipette body mounting assembly 120, thereby performing a dispensing or aspiration operation using the pipette array mounted on the pipette head 100.

[0076] refer to Figures 5 to 12 , the pipette body mounting assembly 120 and the plunger mounting assembly 140, the pipette body clamping mechanism 130 and the plunger clamping mechanism 150, and the dispensing drive actuator assembly 160 are discussed in more detail.

[0077] like Figures 5 to 7 As shown, the pipette body clamping mechanism 130 includes a pipette body clamping plate 125 located below the pipette body mounting plate 121, and a pipette body clamping drive mechanism 133 including a linear actuator and pipette body clamping drive links 134, 135. The linear actuator includes a pipette body clamping motor 132, which is fixed relative to the head chassis 101 and is coupled to the pipette body clamping plate 125 through the pipette body clamping drive links 134, 135 to move the clamping plate 125 in an axial direction when the pipette body clamping motor 132 is actuated to selectively engage the pipette body clamping mechanism 130. The pipette body clamping motor 132 is fixed to the top surface of the upper head chassis component 102. The pipette body clamp drive linkage includes a support plate 134 coupled to the linear actuator and a plurality of abutments 135 extending between the support plate 134 and the pipette body clamping plate 125. The linear actuator also includes a threaded mechanism 136 connected to the support plate 134 and configured to convert the rotation of the clamping motor 132 into an axial displacement of the abutments 135 and the clamping plate 125. In this embodiment, the abutments are provided in the form of guide rods 135 which are connected at their upper ends by an intermediate head chassis component ( Figure 4 The linear bushing 115 of feature 104) is radially supported at its lower end by the lower head chassis member ( Figure 4 The guide rods 135 are also radially supported by linear bushings 173 disposed in each of the four corners of the plunger mounting assembly 140 between their upper and lower ends. In this embodiment, there are four guide rods, one at each corner of the clamping plate 125. In other embodiments, fewer or more guide rods or supports may be provided. For example, the plurality of supports may consist of two supports positioned on opposite sides of the clamping plate 125, such as at a midpoint between the front and rear of the clamping plate 125.

[0078] The screw mechanism 136 includes a ring gear 137 that is coupled to the support plate 134 (see Figure 7). The ring gear 137 is supported by a bearing 131, which is disposed between the upper head chassis component 102 and the ring gear 137. In this way, the ring gear 137 is fixed in the axial direction relative to the head chassis 101 and can rotate around the drive axis 190. The clamping motor 132 drives a drive gear 138, the teeth of which mesh with the teeth of the ring gear 137. The ring gear 137 includes a hollow shaft 137A having a central hole extending in the axial direction (i.e., along the drive axis 190) and a radial flange 137B having a plurality of gear teeth 137C. The radial flange 137B can extend radially outward from the hollow shaft 137A. In the illustrated embodiment, the hollow shaft 137A of the ring gear 137 extends within the threaded hole 134A of the support plate 134, and the threaded connection between the ring gear 137 and the support plate 134 is provided by threads on the outer surface of the hollow shaft 137A of the ring gear 137 and complementary threads on the inner surface of the threaded hole 134A of the support plate 134. The hole of the support plate 134 and the hollow shaft 137A together define a central hole or an axial hole. In other embodiments, the support plate 134 may include a hollow shaft 134A extending within the hole of the hollow shaft 137A of the ring gear 137, wherein the threaded connection is provided by threads on the outer surface of the hollow shaft 134A of the support plate 134 and complementary threads on the inner surface of the hollow shaft 137A of the ring gear 137.

[0079] When the clamping motor 132 is operated, the drive gear 138 rotates the ring gear 137, which causes the support plate 134 to move axially relative to the ring gear 137 by means of a threaded connection between the ring gear 137 and the support plate 134. The rotation of the clamping motor 132 in a first direction causes the support plate 134 to move upward in the axial direction. The rotation of the clamping motor 132 in the opposite second direction causes the support plate 134 to move downward in the axial direction. Since the support plate 134 is fixed to the clamping plate 125 by the guide rod 135, the clamping plate 125 moves axially with the support plate 134 to move toward or away from the pipette body mounting plate 121. With this configuration of the guide rod, when the plunger mounting assembly 140 is moved by the dispensing drive actuator assembly, the plunger mounting assembly 140 can slide axially along the guide rod; and when the pipette body clamping mechanism 130 is operated, the guide rod can move axially along the linear bushing. In this way, the support performs a dual function, transmitting the axial drive from the support plate 134 to the clamping plate 125, and providing a guide along which the plunger mounting assembly 140 is slidably supported. The guide rod 135 helps to maintain the parallel relationship between the pipette body mounting plate 121, the pipette body clamping plate 125 and the plunger mounting assembly 140. Due to the dual function of the guide rod 135, it is not necessary to provide components to guide the movement of the plunger mounting assembly 140 and to transmit the axial displacement of the support plate 134 to the pipette body clamping plate 125. This frees up space in the head chassis 101, allowing the use of a larger diameter guide rod 135 while still maintaining a compact structure in the pipette head. This can reduce the degree of bending in the guide rod and thereby maintain the parallel relationship between the moving plates, thereby further improving the performance of the pipette head. For example, the diameter of the guide rod 135 can be between 8mm and 16mm, such as 12mm.

[0080] Figure 81 is an enlarged cross-sectional view of a pipette body mounting plate 121 and a pipette body clamping plate 125. The pipette body mounting plate 121 has an array of holes 122 extending axially through the thickness of the pipette body mounting plate 121. Fixed within each hole 122 is a pipette body mounting member 123 extending from the plate 121 in a downward axial direction and configured to couple with one of the pipette bodies during use. Each pipette body mounting member 123 is in the form of a tubular pipette body mounting sleeve that is retained in one of the array of holes 122. In this example, the holes 122 each have a restriction with a diameter that is less than the outer diameter of the pipette body mounting sleeve 123. The restriction prevents the pipette body mounting sleeve 123 from being forced through the pipette body mounting plate in an upward direction when the pipette body mounting sleeve is initially inserted into the pipette body. The upper end of the pipette body mounting sleeve 123 preferably includes an end surface that tapers inwardly to assist in inserting the components of the plunger clamping mechanism through the hole of the pipette body mounting sleeve 123. The lower end of the pipette body mounting sleeve 123 preferably has an end surface that tapers outwardly to assist in inserting the lower end of the pipette body mounting sleeve into the pipette body. The outer surface of each pipette body mounting sleeve 123 includes a radially extending feature located on its outer surface, which is configured to form half of a snap-fit ​​connection with a correspondingly shaped feature on the inner surface of the pipette body. In this example, the radial extension is in the form of an annular groove 124 that circumscribes the body mounting sleeve 123.

[0081] The pipette body clamping plate 125 has an array of holes 126 extending in an axial direction through the thickness of the pipette body clamping plate 125. The array of holes 126 corresponds in number and position to the array of holes 122 of the pipette body mounting plate 121. The pipette body clamping plate 125 also includes an array of pipette body clamping members 127, each pipette body clamping member 127 being associated with one of the plurality of pipette body mounts 123. In this example, the array of pipette body clamping members 127 is provided in the form of a plurality of clamping sleeves 127 defined by regions of the pipette body clamping plate 125 that directly surround the holes 126 defined in the pipette body clamping plate 125. Each clamping sleeve 127 has a clamping region 128 having an inner diameter that is greater than the outer diameter of its corresponding pipette body mounting sleeve. In this way, when the pipette body clamping mechanism 130 is engaged, a small gap is provided between the outer surface of the pipette body mounting sleeve 123 and the inner surface of the clamping area 128, such as Figure 8 The pipette body clamping plate 125 is transferred between an engaged and a disengaged (or "released") state by the pipette body clamping drive mechanism 133 .

[0082] When the clamping plate 125 is positioned against or proximate the underside of the pipette body mounting plate 121, the clamping sleeve 127 is axially offset from the annular groove 124 on the pipette body mounting member 123. This is a disengaged state, in which a pipette body can be placed on or removed from the pipette body mounting member 123 without interference from the clamping plate 125. To engage the pipette body clamping mechanism, the clamping plate 125 is moved axially away from the pipette body mounting plate 121 until the clamping area 128 of the clamping sleeve 127 abuts the annular groove 124 on the pipette body mounting member 123. This is an engaged state, in which the clamping sleeve blocks or prevents the pipette body from being removed from the pipette body mounting member 123 by preventing the snap connection between the pipette body and the pipette body mounting member 123 from being disconnected.

[0083] Each clamping sleeve may have a substantially constant inner diameter. Figure 8 As shown, each clamping sleeve 127 can have different areas of inner diameter. In the example shown, each clamping sleeve 127 has a narrow area 129A towards its upper end, and a tapered area 129B at its bottom end. In the tapered area 129B, the inner diameter of the clamping sleeve 127 gradually decreases from the lowermost end to the clamping area 128. Through this arrangement, one or more pipette bodies can be semi-fixed by being positioned in the middle "pre-locking" position in the pipette body clamping plate 125, in which the tapered area 129B of the clamping sleeve 127 is adjacent to the recess or annular groove 124 on the outer surface of the pipette body mounting sleeve 123. This helps to pick up the part array of the body from the box. Once the picked body has been raised above the array that has not been picked up, the picked pipette body can then be clamped in place by moving the pipette body clamping plate 125 to the clamping position. A small gap may be provided between the narrow region 129A of the clamping sleeve 127 and the outer surface of the pipette body mount 123. This may help minimize the force required to axially move the pipette body clamping plate 125 and help the pipette body clamping mechanism 130 operate smoothly.

[0084] Fig. 9 1 is a cross-sectional view of the plunger mounting assembly 140 and the plunger clamping mechanism 150. The plunger mounting assembly 140 and the plunger clamping mechanism 150 are movable together in the axial direction by the dispensing drive actuator assembly 160. The plunger clamping mechanism 150 is movable relative to the plunger mounting assembly 140 in the axial direction.

[0085] like Figures 9 to 11As best shown, the plunger mounting assembly 140 includes a plunger mounting plate 141 having a plurality of holes 142. The plunger mounting assembly 140 includes a box-shaped housing 170 within which components of the plunger mounting assembly 140 and the plunger clamping mechanism 150 are at least partially housed. For ease of assembly, the housing 170 preferably has a two-part structure, including an upper housing and a lower housing secured together around the plunger clamping mechanism 150. The plunger mounting plate 141 forms a lower surface of the housing 170. The housing 170 is rectangular in cross-sectional shape view and includes an axially extending linear bushing 173 at each corner. The linear bushing 173 is supported within a hole 174 in the housing 170 such that Fig. 9 The entire assembly shown in FIG. 1 can be moved up and down along the guide rod of the pipette body clamping mechanism.

[0086] The plunger clamping mechanism 150 includes a plunger clamping plate 145 located above the plunger mounting plate 141, a plurality of plunger clamping members 147 (see Fig.11 ), and a plunger clamping drive mechanism 153 operable to selectively engage the plunger clamping mechanism. The plunger clamping drive mechanism includes a linear actuator 153, which is configured to drive relative axial movement between the plunger clamping plate and the plunger mounting assembly to selectively engage the plunger clamping mechanism. The linear actuator 153 includes a plunger clamping motor 152, which is fixed relative to the plunger clamping plate 145 and coupled to the plunger mounting assembly 140 to move the plunger clamping plate 145 in an axial direction relative to the plunger mounting plate 141, thereby selectively engaging the plunger clamping mechanism 150 when the clamping motor 152 is actuated. The plunger clamping mechanism 150 also includes a plunger clamping support plate 154 and a motor support plate 154A fixed to the plunger clamping support plate 154. The plunger clamping plate 145 is fixed to the lower side of the plunger clamping support plate 154. The plunger clamping mechanism may also include a plunger clamping guide 155 that guides the plunger clamping plate 145 during movement of the plunger clamping mechanism 150. In this embodiment, the plunger clamping guide 155 is fixed relative to the plunger clamping support plate 154 and slides within a hole 175 in the housing 170 located inside the hole 174. In other embodiments, the plunger clamping guide may be fixed to the housing 170 and the support plate includes a hole that slides along the outside of the guide.

[0087] The plunger clamping drive mechanism 153 includes a screw mechanism 156 configured to convert the rotation of the clamping motor 152 into an axial displacement of the clamping plate 145. The screw mechanism 156 includes a ring gear 157 and a hollow shaft 176 coupled together by a threaded connection. The hollow shaft 176 extends along the drive axis 190 and is fixed to the housing 170 of the plunger mounting assembly 140. The ring gear 157 is supported by a bearing 151 disposed between the plunger clamping support plate 154 and the ring gear 157. In this way, the ring gear 157 is fixed in the axial direction relative to the plunger clamping support plate 154 and can rotate around the drive axis 190. The ring gear 157 includes a central hole 157A extending in the axial direction (i.e., along the drive axis 190), and a radial flange 157B having a plurality of gear teeth 157C. The radial flange 157B can extend radially outward from the hollow shaft 157A. The bore of the hollow shaft 176 and the bore of the ring gear 157 together define a central or axial bore. In the illustrated embodiment, the bore 157A of the ring gear 157 extends around the hollow shaft 176 fixed to the housing 170, and the threaded connection between the ring gear 157 and the hollow shaft 176 is provided by threads on the outer surface of the hollow shaft 176 and complementary threads on the inner surface of the bore 157A of the ring gear 157. In other embodiments, the ring gear 157 may include a threaded shaft extending within the bore of the hollow shaft 176 of the housing 170, and the threaded connection is provided by threads on the outer surface of the hollow shaft of the ring gear 157 and complementary threads on the inner surface of the hollow shaft 176.

[0088] The clamping motor 152 drives a drive gear 158, the teeth of which mesh with the teeth 157C of the ring gear 157. When the clamping motor 152 is operated, the drive gear 158 causes the ring gear 157 to rotate about the hollow shaft 176. Due to the threaded connection between the ring gear 157 and the hollow shaft 176, the rotation of the ring gear 157 causes the ring gear 157 to move axially upward or downward on the hollow shaft 176. Due to the axial fixation of the ring gear 157 relative to the plunger clamping support plate 154, the axial movement of the ring gear 157 causes the axial movement of the rest of the plunger clamping mechanism 150, except for the hollow shaft 176 fixed relative to the housing 170. The rotation of the clamping motor 152 in a first direction causes the ring gear 157 to move upward in the axial direction along the hollow shaft 157. The rotation of the clamping motor 152 in the opposite second direction causes the plunger clamping mechanism 150 to move downward in the axial direction. Since the clamping plate 145 is fixed to the plunger clamping support plate 154 , the clamping plate 145 moves axially together with the plunger clamping support plate 154 to move toward or away from the plunger mounting plate 141 .

[0089] Fig.111 is a partial enlarged cross-sectional view of the plunger mounting assembly 140 and the plunger clamping mechanism 150, showing the plunger mounting plate 141 and the plunger clamping plate 145 in more detail. The plunger mounting plate 141 has an array of holes 142 that extend axially through the thickness of the plunger mounting plate 141. Fixed within each hole 142 is a plunger mounting member 143 that extends from the plate 141 in a downward axial direction and is configured to couple with one of the plungers during use. Each plunger mounting member 143 is in the form of a tubular plunger mounting sleeve retained in one of the array of holes 142. In this example, each plunger mounting member 143 has a shoulder having an outer diameter greater than the diameter of the hole 142 and abutting against the underside of the plunger mounting plate 141. The shoulder helps set the height of the plunger mounting sleeve 143 when the plunger mounting sleeve 143 is initially inserted into the hole 142 in the plunger mounting plate 141. The lower end of the pipette body mounting sleeve 143 preferably has an end surface that tapers inwardly to facilitate insertion of the plunger into the hole of the plunger mounting sleeve 143. Each plunger mounting sleeve 143 includes a radially extending feature on its inner surface that is configured to form one half of a snap-fit ​​connection with a correspondingly shaped feature on the outer surface of the plunger. In this example, the radially extending feature is in the form of an annular groove 144 in the inner surface of the plunger mounting sleeve 143 toward its lower end.

[0090] The plunger clamping plate 145 has an array of axially extending recesses or holes 146. The array of holes 146 of the plunger clamping plate 145 corresponds in number and position to the array of holes 142 of the plunger mounting plate 141. The array of holes 146 of the plunger clamping plate 145 may also correspond in number to the array of holes 122 of the pipette body mounting mechanism and the array of holes 126 of the clamping mechanism. The plunger clamping plate 145 also includes an array of plunger clamping members 147, each of which is associated with one of the plurality of plunger mounts 143. The array of plunger clamping members is provided in the form of a plurality of clamping rods 147 extending axially from the plunger clamping plate 145 and extending into holes defined in the plunger mounting sleeve 143. Each clamping rod 147 has an enlarged head 148 at its lower end extending from a narrower neck region 149A. The outer diameter of the enlarged head 148 is smaller than the inner diameter of the plunger mounting sleeve 143. In this way, when the plunger clamping mechanism is engaged, a small gap is formed between the outer surface of the enlarged head 148 and the inner surface of the plunger mounting sleeve 143. The outer diameter of the neck 149A is smaller than the outer diameter of the enlarged head 148. Preferably, each clamping rod 147 also has a spindle 149B, the outer diameter of the spindle 149B being substantially the same as the inner diameter of the area of ​​the plunger mounting sleeve 143 where it is located. When the plunger clamping plate 145 moves up and down in the axial direction relative to the plunger mounting plate 141, the spindle 149B moves axially along the hole of the plunger mounting member 143.

[0091] The relative movement between the plunger clamping plate 145 and the plunger mounting plate 141 allows the plunger clamping mechanism 150 to move to any position between an engaged state in which the plunger is clamped in place and a disengaged position (or "release" position or state) in which the plunger can be engaged with or removed from the plunger mounting member in an axial direction. The plunger clamping mechanism 150 can be configured to move to an ejection state in which the plunger clamping plate 145 moves toward the plunger mounting plate 141 beyond the clamping position. In this position, the enlarged head 148 of the clamping rod 147 is axially lower than the radially extending feature on the inner surface of the plunger mounting sleeve 143, and the radially extending feature is aligned with the narrower neck 149A of the clamping rod. This allows the top of the plunger (i.e., the plunger connector portion) to flex inward. Further downward movement of the clamping plate 145 and the clamping rod 147 pushes the plunger downward to release the plunger from the snap connection with the plunger mounting sleeve. When the pipette body clamping plate 125 is also in the release position, by using the plunger clamping drive mechanism, the further downward movement of the clamping rod pushes the plunger against one or more inner surfaces of the pipette body (e.g., the area around the hole at the distal end of the pipette body) to push the pipette body from the pipette body clamping mechanism. This will eject the entire pipette assembly from the pipette head. Alternatively, by using the direct drive actuator 160, the clamping rod and the plunger can move downward together to push the pipette, thereby ejecting the pipette body from the device. In this mode, the plunger can remain on the device even after the pipette body has been ejected.

[0092] like Fig.12 As best shown in , the dispensing drive actuator assembly 160 includes a dispensing drive motor 161 and a dispensing drive mechanism 162, through which the dispensing drive motor 161 is directly coupled to the plunger mounting assembly 140 to drive its axial displacement. The dispensing drive motor 161 is mounted on the top surface of the upper head chassis component 102. The dispensing drive mechanism 162 includes an output shaft 165 of the dispensing drive motor 161, a screw 163 and a ball screw actuator nut 164, which together with the ball screw actuator nut 164 form a ball screw actuator. The output shaft of the drive motor 161 can be integral with the screw 163, that is, integrated with the screw 163, or a separate component fixed relative to the screw 163 to rotate therewith. The ball screw nut 164 is axially fixed relative to the plunger mounting assembly 140 so that both move along the screw 163 simultaneously when the screw 163 rotates. In the illustrated embodiment, the ball screw nut 164 is secured within a hollow shaft 176 of the housing 170 of the plunger mounting assembly 140 .

[0093] The screw 163, the ball screw actuator nut 164, the screw mechanism 136, and the screw mechanism 156 are all coaxial. In other words, the central axes of all of these components are aligned along a common axis. One or both of the output shaft 165 of the drive motor 161 and the screw 163 extend through an axial hole defined by the screw mechanism 136 of the pipette body clamping mechanism. One or both of the screw 163 and the ball screw nut 164 can extend through an axial hole defined by the screw mechanism 156 of the pipette body clamping mechanism. In this way, the dispensing drive mechanism 162 is concentric with the screw mechanism 136 and the screw mechanism 156 along at least a portion of the length of the dispensing drive mechanism 162.

[0094] With this arrangement, the forces applied by the various drive mechanisms all act along the same single axis, which is preferably a central axis. This helps to keep the movable plates parallel to each other to promote smooth operation and reduce the risk of deflection. In addition, each drive mechanism applies force at a single location. This avoids the risk of deflection due to uneven force applied at multiple locations. For example, where a force is applied at each of the four corners of a plate by a pulley and belt arrangement, failure to maintain force evenly at each pulley may even result in deflection of the plate.

[0095] refer to Figure 5, when the dispensing drive actuator assembly 160 is operated, the entire plunger mounting assembly 140 moves along the guide rod 135 in an axial direction toward or away from the pipette body mounting assembly 120, depending on the direction of rotation of the dispensing drive motor 161. The linear bushing 173 slides along the outer surface of the guide rod 135 so that the plunger held by the plunger mounting assembly 140 can be quickly and accurately accelerated relative to the pipette body in which the plunger extends, and is independent of any restrictions imposed by the operating speed of the clamping mechanism. This allows the device to be used in a non-contact dispensing mode (also known as a jet, in which the liquid is dispensed from the pipette at a distance from the target so that the droplets separate from the end of the pipette body before contacting the target) as well as a contact dispensing mode (in which the droplets are formed at the end of the pipette body and deposited by contact with the target). When performing non-contact dispensing, the liquid sample must be detached from the end at a sufficiently high speed. The distance traveled by the plunger for dispensing the jet can be very small, for example in the range of 1 mm or less. Therefore, in order to achieve the target speed of non-contact dispensing, a high level of acceleration / deceleration is required. The linear bushing 173 is aligned with the mating parts of the pipette head assembly to minimize tolerance stacking. In addition, it has been found that the use of a linear bushing is an extremely effective way to maintain verticality or parallelism between the plunger mounting assembly and the pipette body mounting assembly and the pipette body clamping mechanism. A direct drive arrangement (e.g., via a ball screw) can provide a higher level of heavy-load acceleration / deceleration than a belt drive system, thereby achieving non-contact dispensing of small volume liquid samples. In addition, a direct drive arrangement can provide higher positional accuracy and repeatability than an equivalent belt drive mechanism. This can have a significant impact on dispensing performance.

[0096] In this manner, dispensing drive mechanism 162 is concentric with screw mechanism 136 and screw mechanism 156 along at least a portion of the length of dispensing drive mechanism 162 .

[0097] Figures 13 to 17 Shown with Figures 2 to 12 The pipette 1010 is used together with the pipette head. The pipette 1010 includes a pipette body 1100 and a plunger 1200.

[0098] The pipette body 1100 may be a container for receiving and / or containing a sample fluid or sample liquid. The pipette body 1100 may be configured to be inserted into a container of sample liquid or into a sample liquid. The pipette body 1100 has a proximal end 1101 and a distal end 1102, and a longitudinal axis 1001 is defined between the proximal end 1101 and the distal end 1102. The pipette body 1100 has a hole 1108 at its distal end 1102, such as Fig.15As shown. The hole 1108 may be defined by an inner wall surface 1111 of the pipette body 1100 at the distal end 1102 (specifically, at the outermost distal point of the pipette body 1100). The hole 1108 may be any suitable shape, such as an elliptical, oval or circular shape. The pipette body 1100 has a fluid cavity 1109 that extends at least partially from the hole 1108 toward the proximal end 1101. The fluid cavity may be configured to receive and / or hold a fluid, such as an air gap or a sample liquid. The fluid cavity 1109 may be substantially elongated. The fluid cavity may be defined by an inner wall surface of the pipette body 1100. The longitudinal axis 1001 may be a central axis around which the pipette body 1100 and / or the plunger 1200 are arranged. The longitudinal axis 1001 may define a central axis around which the pipette body 1100 and / or the plunger 1200 are evenly or symmetrically arranged. The pipette body 1100 and / or the plunger 1200 can be configured such that the direction of aspiration and / or dispensing is along the longitudinal axis 1001. The pipette body 1100 can be substantially elongated, extending between its proximal end 1101 and distal end 1102. The pipette body 1100 can be substantially or completely hollow. The pipette body 1100 can include or consist of a polymeric material. The pipette body 100 can include or consist of a homogenous material. The pipette body 100 can include or consist of a translucent or transparent material.

[0099] The pipette body 1100 may include a series of components, each having different functions, distinguishing features and / or different shapes or sizes. The pipette body 1100 may include one or more of a pipette body connector portion 1103, a centering portion 1104, a support portion 1105, a main body portion 1106, and a bridge portion 1107, such as Fig.15 As shown. From the proximal end 1101 to the distal end 1102, each component can be arranged in the following order: pipette body connector portion 1103, centering portion 1104, support portion 1105, main body portion 1106, bridge portion 1107 and end portion 1110. The fluid chamber 1109 can extend through one, more than one, or all of the components of the pipette body 1100. The plunger 1200 can extend through one, more than one, or all of the components of the pipette body 1100.

[0100] The pipette body connector portion 1103 is configured for connection to a liquid handling system, for example, using a snap connection. The pipette body connector portion 1103 may include a split tubular wall 1120, which may be defined by a plurality of flexible segments 1121. The flexible segments 1121 may be configured to resiliently deflect in a radially inward direction to increase the outer diameter of the proximal end 1101 of the pipette body 1100 from a first outer diameter to a second outer diameter, in which the flexible segments are not deflected and the pipette body connector portion is in a static state, and in which the flexible segments are radially deflected outward and the pipette body connector portion is in an expanded state. In the illustrated embodiment, the pipette body connector portion 1103 includes four axially extending interruptions or slots 1122 in the tubular wall 1120 that separate the four flexible segments 1121. The pipette body connector portion 1103 may include any suitable number of axially extending interruptions 1122 to define any number of flexible segments 1121, for example, two, three, four, five, or six. The arrangement of the flexible segments 1121 and the slots 1122 enables the pipette body connector portion to expand without requiring significant force to be applied to the pipette body connector portion. This can reduce the insertion force required to engage the pipette body connector portion 1103 with the pipette head.

[0101] The pipette body connector portion 1103 may also include one or more radially extending features 1123 located on its inner surface, by which the pipette body can be coupled to the pipette head. The radially extending features on the inner surface of the pipette body connector portion 1103 may include radially inwardly extending protrusions and / or radially outwardly extending recesses or grooves. The radially extending features may extend in a circumferential direction. In the illustrated embodiment, the radially extending features on the inner surface of the pipette body connector portion 1103 include a partially annular rib 1123 protruding from the inner surface of the pipette body connector portion 1103. Preferably, the second outer diameter to which the pipette body connector portion is increased is greater than the first outer diameter by at least the radial extent of the radially extending features 1123. The rib 1123 preferably includes an angled upper surface and a lower surface, and the inner diameter of the pipette body connector portion gradually increases from the rib 1123 along the upper and lower surfaces of the rib 1123 to the area of ​​the pipette body connector portion above and below the rib 1123. The angle of the upper surface can be selected according to the required insertion force. The angle of the lower surface can be selected according to the desired ejection force. The upper surface or the lower surface can each have an angle of 10 to 80 degrees with the axial direction of the pipette body, for example 20 to 70 degrees with the axial direction of the pipette body, 30 to 60 degrees with the axial direction of the pipette body, or 40 to 50 degrees with the axial direction of the pipette body.

[0102] The centering portion 1104 can be configured to center the plunger 1200 within the pipette body 1100. The centering portion 1104 can have a tapered or conical inner surface. The support portion 1105 can include one or more structural ribs or rings configured to reduce the flexibility and / or improve the structural integrity of the pipette body 1100. The one or more ribs can extend (e.g., axially) along at least a portion of the length between the proximal end 1101 and the distal end 1102 on the outer surface of the pipette body, such as Fig.16 As best shown. The main body 1106 can be generally cylindrical and / or elongated. The main body 1106 can have a substantially uniform inner diameter and / or outer diameter. The main body 1106 can extend along at least half of the length of the pipette body 1100. The main body 1106 can have an inner diameter and / or outer diameter that is larger than any diameter of the end 1110. The bridge 1107 can be configured to bridge the main body 1106 to the end 1110. The bridge 1107 can define a gradual transition or step between the main body 1106 and the end 1110. The bridge 1107 can be generally tapered, conical and / or dome-shaped.

[0103] The plunger 1200 has a proximal end 1201 and a distal end 1202 extending 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 body 1100. The plunger 1200 can be configured to extend substantially or completely into the end 1110 between the proximal end 1101 and the distal end 1102 of the pipette body 1100. The plunger 1200 can move toward and away from the aperture 1108 to aspirate or dispense fluid from the pipette body 1100. The plunger 1200 can have an end outer wall surface 1212 configured to align with an inner wall surface 1111 of the pipette body end 1110. The plunger 1200 can include or consist of a polymeric material. The plunger 1200 can include or consist of a homogenous material.

[0104] The plunger 1200 may include a series of components, each having a different function, distinguishing features, and / or a different shape or size. The plunger 1200 may include one or more of a plunger connector portion 1203, a centering portion 1204, a body portion 1206, and a sealing portion 1207. From the proximal end 1201 to the distal end 1202, each component may be arranged in the following order: connector portion 1203, centering portion 1204, body portion 1206, sealing portion 1207, and end portion 1210.

[0105] The plunger connector portion 1203 is configured for connection to a liquid handling system, for example, by a snap connection. The plunger connector portion 1203 can be configured to be completely contained within the pipette body connector portion 1103 of the pipette body 100. The plunger connector portion 1203 can include a split tubular wall 1220, which can be defined by a plurality of flexible segments 1221. The flexible segments 1221 can be configured to resiliently deflect in a radially inward direction to reduce the inner diameter of the proximal end 1201 of the plunger 1200 from a first inner diameter to a second inner diameter, in which the flexible segments are not deflected and the plunger connector portion is in a static state, and in which the flexible segments are radially deflected inward and the plunger connector portion is in a compressed state. In the illustrated embodiment, the plunger connector portion 1203 includes three axially extending interruptions or slots 1222 in the tubular wall 1220 that separate the three flexible segments 1221. The plunger connector portion 1203 may include any suitable number of axially extending interruptions 1222 to define any number of flexible segments 1221. The arrangement of the flexible segments 1221 and the slots 1222 enables the plunger connector portion to be compressed without significant compressive stress. The plunger connector portion 1203 may also include one or more radially extending features 1223 on its outer surface, through which the plunger can be coupled to the pipetting head. The radially extending features on the outer surface of the plunger connector portion 1203 may include radially outwardly extending protrusions and / or radially inwardly extending recesses or grooves. The radially extending features may extend in the circumferential direction. In the illustrated embodiment, the radially extending features on the outer surface of the plunger connector portion 1203 include a spherical head 1223 located at the upper end of the plunger, which is defined above the annular groove on the outer surface of the plunger connector portion 1203. Preferably, the second inner diameter to which the plunger connector portion is reduced is smaller than the first inner diameter by at least the radial extent of the radially extending feature 1223, ie, at least half the difference between the outer diameter of the ball head 1223 and the outer diameter of the narrowest portion of the annular groove.

[0106] The plunger connector portion 1203 may also include an inner wall 1224 extending laterally from the inner surface of the plunger connector portion 1203. The inner wall 1224 may be distal to the flexible section 1221. The inner wall 1224 may be proximal to the body portion 1206. The inner wall 1224 forms a restriction through the hole of the plunger connector portion. This provides a surface against which the head of the clamping rod may rest to eject the pipette. Fig.17 As shown, the inner wall 1224 can extend through the entire width of the inner hole of the plunger 1200. However, this is not always the case. The inner wall 1224 only needs to limit the size of the hole to be smaller than the outer diameter of the clamping rod head.

[0107] The centering portion 1204 may include an annular shoulder. The centering portion 1204 may be substantially conical or dome-shaped. In the illustrated embodiment, the centering portion 1204 is a radially extending frustoconical shoulder. The centering portion 1204 of the pipette body 1100 is preferably configured to receive and engage the centering portion 1204 of the plunger 1200 to align the center of the plunger. Fig.14 In the illustrated embodiment, the two centering portions have corresponding geometric shapes. The main body 1206 of the plunger 1200 can be configured to be accommodated in the main body 1106 of the pipette body 1100. The main body 1206 can be substantially cylindrical and / or elongated. The main body 1206 can have a substantially uniform diameter. The main body 1206 can extend along at least half of the length of the plunger, optionally, along at least two-thirds of the length of the plunger 1200. The diameter of the main body 1206 can be greater than the diameter of the end 1210. The sealing portion 1207 of the plunger 1200 can be configured to be accommodated in the bridge portion 1107 of the pipette body 1100. The sealing portion 1207 can be configured to abut against the inner wall of the pipette body 1100 to form a seal. The sealing portion 1207 can form a fluid-tight seal within the pipette body so that when the plunger 1200 is installed in the pipette body 1100, the fluid cannot flow from the proximal side of the sealing portion 1207 to the distal side of the sealing portion 1207. The sealing portion 1207 can be at least partially flexible. The sealing portion 1207 can be configured to bridge the main body 1206 to the end 1210. The sealing portion 1207 can define a step between the main body 1206 and the end 1210. The sealing portion 1207 can be substantially conical, conical and / or dome-shaped. The end 1210 of the plunger 1200 can be configured to be accommodated in the end 1110 of the pipette body 1100. The end 1210 can have a smaller diameter than the sealing portion 1207 and / or the main body 1206.

[0108] refer to Figures 17 to 21 , a method of connecting a pipette 1010 to the present invention's pipette head 100 will now be described. Although the following discussion relates to drawings that show only a single pipette, it should be understood that one or more of the discussed connection, aspiration, dispensing, and ejection operations can be applied to multiple pipettes simultaneously. For example, when the pipette head includes 384 mountings, the following discussion can be applied to the simultaneous connection of 384 pipettes or any subset thereof.

[0109] exist Fig.17, the pipette body clamping mechanism 130 and the plunger clamping mechanism 150 are both in their released states. When the pipette body clamping mechanism 130 is in the released state, the pipette body clamping plate 125 is in its highest position against the lower side of the pipette body mounting plate 121. Most importantly, in this position, the clamping area of ​​the pipette body clamping sleeve is axially offset from the annular groove surrounding the outer surface of the pipette body mounting sleeve. As shown, when the plunger clamping mechanism 150 is in its released state, the plunger clamping plate 145 is in its highest position, and the enlarged head 148 of the plunger clamping rod 147 is axially offset from the annular groove on the inner surface of each plunger mounting sleeve. Then, the entire pipette head 100 is axially moved toward the array of pipettes 1010 using the pipette head Z motor (not shown) so that the pipette body mounting sleeve is accommodated in the pipette body connector portion of the pipette body 1100. During insertion of the pipette body mounting sleeve 123 into the proximal end of the pipette body 1100, the annular rib 1123 on each pipette body 1100 straddles the outer surface of the pipette body mounting sleeve 123, causing the pipette body connector portion of each pipette body to deflect outwardly to an extended position. Fig.17 As shown, once the annular rib 1123 is received in the annular groove 124, the flexible section returns to an undeflected state or only a partially deflected state. In this position, the pipette body connector portion is in a static state, and each pipette body 1100 is coupled to its corresponding pipette body mounting sleeve 123 in a snap-fit ​​manner. This is step 1.

[0110] refer to Fig.18 Discussing step 2. In step 2, the pipette body clamping mechanism 130 is engaged by lowering the pipette body clamping plate 125 away from the pipette body mounting plate, such as Fig.18 As shown. This results in the pipette body clamping sleeve 127 extending around the pipette body connector portion 1103 of each pipette body 1100, so that the clamping area of ​​each pipette body clamping sleeve is adjacent to the snap connection between each pipette body 1100 and its corresponding pipette body mounting sleeve 123. The inner diameter of the clamping area 128 is smaller than the expanded diameter of the pipette body connector portion 1103, for example, it can be substantially the same as the unexpanded outer diameter (or "first" outer diameter) of the pipette body connector portion. By this arrangement, the pipette body connector portion 1103 is prevented from fully expanding, thereby preventing the radially extending features 1123 on the inner surface of the pipette body 1100 from being released from the grooves 124 on the outer surface of the pipette body mounting sleeve 123. In this way, the pipette body 1100 is "locked" or "clamped" in place without any significant force being applied to the pipette body connector portion of the pipette body 1100. This can reduce the force required to engage the pipette body clamping mechanism.

[0111] Between steps 1 and 2, the pipette body clamping mechanism may optionally be moved to a partially engaged "pre-lock" position between a released state and an engaged state, in which the tapered region 129B of each clamping sleeve 127 is adjacent to a recess 124 on the outer surface of its corresponding pipette body mounting sleeve 123. This may facilitate picking of a partial array of bodies from a cassette by allowing the picked body to be secured against the pipette body mount without interference between the pipette body clamping plate and the array of unpicked bodies. Once the picked body has been lifted above the unpicked array by the pipette head, the picked body may then be fully clamped in place by moving the pipette body clamping plate 125 to the clamping position.

[0112] refer to Fig.19 Discuss step 3. In step 3, the entire plunger mounting assembly 140 is lowered using the dispensing drive actuator. This causes the plunger mounting 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 mounting assembly 140 causes the inner surface of the plunger mounting sleeve 143 to straddle the outer surface of the plunger connector portion, causing the plunger connector portion to deflect inwardly to a retracted or compressed position and allowing the ball head 1223 at the top of the plunger 1200 to be received in the groove 144 on the inner surface of the plunger mounting sleeve 143. Fig.19 As shown, once the ball head 1223 is received in the groove 144 on the inner surface of the plunger mounting sleeve 143, the flexible section 1221 of the plunger connector portion 1203 returns to an undeflected state or a partially deflected state. In this position, the plunger connector portion is in a static state, and each plunger 1200 is coupled to its corresponding plunger mounting sleeve 143 in a snap-fit ​​connection.

[0113] refer to Fig. 20 Discuss step 4. In step 4, the plunger clamping plate 145 is moved in an axial direction toward the plunger mounting plate 141 by the plunger clamping drive mechanism until the head 148 of the plunger clamping rod is adjacent to the snap connection between the plunger and the plunger mounting sleeve. When in the retracted state, the outer diameter of the head 148 of each clamping rod is greater than the inner diameter (or "second inner diameter") of the plunger. For example, it can be substantially the same as the inner diameter (or "first" inner diameter) of the undeflected plunger. With this arrangement, the plunger connector portion is prevented from fully retracting to the retracted position, thereby preventing the spherical head 1223 of the plunger 1200 from being released from the groove 144 on the inner surface of the plunger mounting sleeve 143. In this way, the plunger 1200 is "locked" or "clamped" in place without the need to apply any significant compressive force on the plunger connector portion. This can reduce the force required to engage the plunger clamping mechanism.

[0114] To perform a pipetting operation, the pipetting head 100 is moved to a desired position relative to a set of liquid samples using the pipetting head Z motor. Fig.21 As shown, the plunger of each pipette is raised within its respective pipette body using a direct drive actuator to move the entire plunger mounting assembly 140 away from the pipette body mounting mechanism 120, thereby drawing fluid into the pipette body. Then, the fluid can be dispensed as needed by moving the plunger clamping mechanism in the opposite direction using the dispensing drive actuator assembly.

[0115] Once the aspiration and dispensing operations are complete, one or more pipettes may be ejected as follows. First, each plunger is moved to the bottom of its travel within its respective pipette body and the pipette body clamping mechanism 130 is disengaged by moving the pipette body clamping plate 125 toward the pipette body mounting plate 121 to disengage the clamping sleeve 127 from the snap connection between each pipette body and its respective pipette body mounting member 123 and to move the clamping sleeve 127 away from the outer surface of the pipette body. Next, the plunger clamping plate 145 is moved toward the plunger mounting plate 141 beyond the engagement position so that the head 148 of each clamping rod 147 is moved to disengage the snap connection between each plunger 1200 and its respective plunger mounting member 143 and so that the neck 149A of each clamping rod 147 is aligned with the snap connection, thereby causing the distal surface of the clamping rod head to abut against the inner wall 1224 of the plunger connector portion 1203. Since the outer diameter of the neck 149A of the clamping rod 147 is smaller than the second compressed inner diameter of the plunger connector portion 1203, the plunger connector portion is not restricted from deflecting inwardly to a compressed state when the clamping rod is in this position. Therefore, the continued downward movement of the plunger clamping plate 145 releases the spherical head 1223 of the plunger connector portion 1203 from the corresponding radially extending feature 144 of the plunger mounting member 143 to remove the plunger 1200 from the pipetting head. Further downward movement of the plunger clamping plate, and therefore further downward movement of the clamping rod and the plunger itself, pushes the distal end of the plunger against the corresponding portion of the pipette body in which they are located. In this way, the plunger and the plunger clamping mechanism can be used to release the pipette body 1100 from the pipette body mounting member 123, thereby ejecting the pipette 1010 from the pipetting head.

[0116] Although the invention has been described above with reference to one or more preferred embodiments, it will be appreciated that various changes or modifications may be made without departing from the scope of the invention as defined in the appended claims.

[0117] The invention may also be described or defined in accordance with the following terms:

[0118] 1. A pipette head for a liquid dispensing device, the pipette head being used with an array of removable pipettes, each pipette having a pipette body and a plunger disposed within the pipette body, the pipette head comprising:

[0119] Pipette head chassis;

[0120] A pipette body mounting assembly, used for holding the pipette body;

[0121] A plunger mounting assembly for holding the plunger;

[0122] a dispensing drive actuator assembly operable to move the plunger mounting assembly relative to the pipette body mounting assembly along a drive axis to perform a dispensing or aspiration operation, the dispensing drive actuator assembly comprising a dispensing drive motor and a dispensing drive mechanism, the dispensing drive motor being coupled to the plunger mounting assembly via the dispensing drive mechanism to drive the plunger mounting assembly to axially displace; and

[0123] A pipette body clamping mechanism operable to selectively clamp the pipette bodies of the pipette array to the pipette body mounting assembly, the pipette body clamping mechanism comprising:

[0124] a pipette body clamping plate, located below the plunger mounting assembly;

[0125] a plurality of pipette body clamping members located on the pipette body clamping plate; and

[0126] 14. The urging means for moving the pipette body clamping mechanism of claim 13, wherein the at least one guide rail is configured to move the pipette body clamping plate relative to the pipette head chassis to selectively engage the pipette body clamping mechanism.

[0127] 2. A pipetting head according to clause 1, wherein the at least one support comprises a plurality of supports, each support being connected to a periphery of the pipette body clamping plate.

[0128] 3. A pipetting head according to clause 1 or clause 2, wherein the at least one support includes at least one guide rod, and the plunger mounting assembly is slidably supported along the guide rod when the plunger mounting assembly is axially moved by the dispensing drive actuator assembly.

[0129] 4. A pipetting head according to any preceding clause, wherein the at least one support is slidably supported by the pipetting head chassis.

[0130] 5. A pipetting head according to any preceding clause, wherein the linear actuator is located above the plunger mounting assembly.

[0131] 6. A pipette head according to any preceding clause, wherein the linear actuator comprises a pipette body clamping motor and a screw mechanism for converting the rotational movement of the pipette body clamping motor into an axial movement of the at least one support.

[0132] 7. A pipetting head according to clause 6, wherein the screw mechanism is hollow and defines an axial bore, and the dispensing drive mechanism extends through the axial bore.

[0133] 8. A pipetting head according to clause 7, wherein the dispensing drive mechanism and the screw mechanism are concentric.

[0134] 9. A pipette head according to clause 7 or clause 8, wherein the screw mechanism comprises a first sleeve and a second sleeve which are concentric and coupled by a threaded connection, and wherein the pipette body clamping motor is configured to rotate the first sleeve around the second sleeve to drive the axial movement of the at least one support.

[0135] 10. The pipetting head of clause 9, wherein the mid-diameter of the threaded connection is less than 30% of the width of the pipette body clamping plate.

[0136] 11. A pipette head according to any one of clauses 6 to 10, wherein the pipette body clamping motor is coupled to the screw mechanism via one or more gears.

[0137] 12. A pipetting head according to any of clauses 6 to 11, wherein the pipette body clamping motor is fixed relative to the pipetting head chassis.

[0138] 13. A pipetting head according to any preceding clause, further comprising a plunger clamping mechanism operable to clamp a plunger of the pipette array to the plunger mounting assembly, the plunger clamping mechanism comprising:

[0139] Plunger clamping plate;

[0140] a plurality of plunger clamping members on the plunger clamping plate; and

[0141] A plunger clamp drive mechanism is operable to selectively engage the plunger clamp mechanism, the plunger clamp mechanism having a linear actuator configured to drive relative axial movement between the plunger clamp plate and the plunger mounting assembly to selectively engage the plunger clamp mechanism.

[0142] 14. The pipetting head according to clause 13, wherein the linear actuator of the plunger clamping drive mechanism comprises a plunger clamping motor and a screw mechanism, wherein the screw mechanism is used to convert the rotational movement of the plunger clamping motor into the axial movement of the plunger clamping plate.

[0143] 15. A pipette head according to claim 14, wherein the screw mechanism of the plunger clamping drive mechanism includes a first sleeve and a second sleeve, the first sleeve and the second sleeve are concentric and coupled by a threaded connection, wherein the second sleeve is fixed relative to the plunger mounting assembly, and wherein the plunger clamping motor is configured to rotate the first sleeve around the second sleeve to drive the axial movement of the plunger clamping plate.

[0144] 16. The pipetting head of clause 15, wherein the mid-diameter of the threaded connection is less than 30% of the width of the plunger clamping plate.

[0145] 17. A pipetting head according to any of clauses 14 to 16, wherein the screw mechanism of the plunger clamp drive mechanism is hollow and defines an axial bore in which a portion of the dispensing drive mechanism is received.

[0146] 18. A pipetting head according to clause 17, wherein the dispensing drive mechanism comprises a ball screw actuator nut, the ball screw actuator nut being at least partially received within an axial bore of a screw mechanism of the plunger clamping drive mechanism.

[0147] 19. A pipetting head according to clause 17 or clause 18, wherein the screw mechanisms of the dispensing drive mechanism and the plunger clamping drive mechanism are concentric.

[0148] 20. A pipette head according to any one of clauses 13 to 19, wherein the plunger mounting assembly comprises a plurality of plunger mountings, and wherein the plurality of plunger clamping members comprise a plurality of clamping rods, each of the clamping rods being coaxial with one of the plurality of plunger mountings and extending within the plunger mounting to limit the inward movement of a plunger accommodated in the plunger mounting when the plunger clamping mechanism is engaged.

[0149] 21. The pipetting head according to clause 20, wherein the plunger mounting assembly further comprises a plunger mounting plate, and the plurality of plunger mounting members are disposed on the plunger mounting plate.

[0150] 22. A liquid dispensing device comprising:

[0151] a body having a platform for receiving one or more microplates; and

[0152] A pipetting head according to any one of clauses 1 to 21, the pipetting head being located above the platform.

[0153] 23. A pipette head for a liquid dispensing device, the pipette head being used with an array of pipettes, each of the pipettes having a pipette body and a plunger disposed within the pipette body, the pipette head comprising:

[0154] Pipette head chassis;

[0155] A pipette body mounting assembly, used for holding the pipette body;

[0156] A plunger mounting assembly for retaining the plunger;

[0157] a dispensing drive actuator assembly operable to move the plunger mounting assembly relative to the pipette body mounting assembly along a drive axis to perform a dispensing or aspiration operation, the dispensing drive actuator assembly comprising a dispensing drive motor and a dispensing drive mechanism, the dispensing drive motor being coupled to the plunger mounting assembly via the dispensing drive mechanism to drive the plunger mounting assembly to axially displace; and

[0158] A plunger clamping mechanism operable to clamp the plunger of the pipette array to the plunger mounting assembly, the plunger clamping mechanism comprising:

[0159] Plunger clamping plate;

[0160] a plurality of plunger clamping members disposed on the plunger clamping plate; and

[0161] A plunger clamp drive mechanism is operable to selectively engage the plunger clamp mechanism, the plunger clamp mechanism having a linear actuator configured to drive relative axial movement between the plunger clamp plate and the plunger mounting assembly to selectively engage the plunger clamp mechanism.

[0162] 24. A pipetting head according to clause 23, wherein the linear actuator of the plunger clamping drive mechanism comprises a plunger clamping motor and a screw mechanism, wherein the screw mechanism is used to convert the rotational movement of the plunger clamping motor into the axial movement of the plunger clamping plate.

[0163] 25. A pipette head according to claim 24, wherein the screw mechanism of the plunger clamping drive mechanism includes a first sleeve and a second sleeve, the first sleeve and the second sleeve are concentric and coupled by a threaded connection, wherein the second sleeve is fixed relative to the plunger mounting assembly, and wherein the plunger clamping motor is configured to rotate the first sleeve around the second sleeve to drive the axial movement of the plunger clamping plate.

[0164] 26. A pipetting head according to clause 25, wherein the pitch diameter of the threaded connection is less than 30% of the width of the plunger clamping plate.

[0165] 27. A pipetting head according to any of clauses 24 to 26, wherein the screw mechanism of the plunger clamp drive mechanism is hollow and defines an axial bore in which a portion of the dispensing drive mechanism is received.

[0166] 28. A pipetting head according to clause 27, wherein the dispensing drive mechanism comprises a ball screw actuator nut, the ball screw actuator nut being at least partially received within an axial bore of a screw mechanism of the plunger clamping drive mechanism.

[0167] 29. A pipetting head according to clause 27 or clause 28, wherein the screw mechanisms of the dispensing drive mechanism and the plunger clamping drive mechanism are concentric.

[0168] 30. A pipette head according to any one of clauses 23 to 29, wherein the plunger mounting assembly comprises a plurality of plunger mountings, and wherein the plurality of plunger clamping members comprise a plurality of clamping rods, each of the clamping rods being coaxial with one of the plurality of plunger mountings and extending within the plunger mounting to limit the inward movement of a plunger accommodated in the plunger mounting when the plunger clamping mechanism is engaged.

[0169] 31. The pipetting head according to clause 30, wherein the plunger mounting assembly further comprises a plunger mounting plate, and the plurality of plunger mounting members are disposed on the plunger mounting plate.

Claims

1. A pipette head for a liquid dispensing device, the pipette head being used with an array of removable pipettes, each pipette having a pipette body and a plunger disposed within the pipette body, the pipette head comprising: Pipette head chassis; A pipette body mounting assembly for holding the pipette body of the removable pipette array a plunger mounting assembly for holding the plungers of the removable pipette array; A dispensing drive actuator assembly, operable to move the plunger mounting assembly along a drive axis relative to the pipette body mounting assembly to perform a dispensing or aspiration operation, the dispensing drive actuator assembly comprising a dispensing drive motor and a dispensing drive mechanism, the dispensing drive motor being coupled to the plunger mounting assembly via the dispensing drive mechanism to drive the plunger mounting assembly to axially displace; as well as A pipette body clamping mechanism operable to selectively clamp the pipette bodies of the pipette array to the pipette body mounting assembly, the pipette body clamping mechanism comprising: a pipette body clamping plate positioned below the plunger mounting assembly; a plurality of pipette body clamping members on the pipette body clamping plate; and 14. The urging means for moving the pipette body clamping mechanism of claim 13, wherein the at least one guide rail is configured to move the pipette body clamping plate relative to the pipette head chassis to selectively engage the pipette body clamping mechanism.

2. The pipetting head according to claim 1, wherein: The at least one support includes a plurality of supports, each of the supports being connected to a periphery of the pipette body clamping plate.

3. The pipetting head according to claim 1 or claim 2, wherein: The at least one mount includes at least one guide rod along which the plunger mounting assembly is slidably supported when the plunger mounting assembly is axially moved by the dispensing drive actuator assembly.

4. A pipetting head according to any one of the preceding claims, wherein: The at least one support is slidably supported by the pipetting head chassis.

5. A pipetting head according to any one of the preceding claims, wherein: The linear actuator is located above the plunger mounting assembly.

6. A pipetting head according to any one of the preceding claims, wherein: The linear actuator comprises a pipette body clamping motor and a screw mechanism for converting the rotational movement of the pipette body clamping motor into an axial movement of the at least one mount.

7. The pipetting head according to claim 6, wherein: The screw mechanism is hollow and defines an axial bore through which the dispensing drive mechanism extends.

8. The pipetting head according to claim 7, wherein: The dispensing drive mechanism and the screw mechanism are concentric.

9. The pipetting head according to claim 7 or claim 8, wherein: The screw mechanism includes a first sleeve and a second sleeve that are concentric and coupled by a threaded connection, wherein the pipette body clamping motor is configured to rotate the first sleeve around the second sleeve to drive the axial movement of the at least one support.

10. The pipetting head according to claim 9, wherein: The mid-diameter of the threaded connection is less than 30% of the width of the pipette body clamping plate.

11. The pipetting head according to any one of claims 6 to 10, wherein: The pipette body clamping motor is coupled to the screw mechanism via one or more gears.

12. The pipetting head according to any one of claims 6 to 11, wherein: The pipette body clamping motor is fixed relative to the pipette head chassis.

13. The pipetting head according to any one of the preceding claims, further comprising a plunger clamping mechanism operable to clamp a plunger of the pipette array to the plunger mounting assembly, the plunger clamping mechanism comprising: Plunger clamping plate; a plurality of plunger clamping members on the plunger clamping plate; as well as A plunger clamp drive mechanism is operable to selectively engage the plunger clamp mechanism, the plunger clamp mechanism having a linear actuator configured to drive relative axial movement between the plunger clamp plate and the plunger mounting assembly to selectively engage the plunger clamp mechanism.

14. The pipetting head according to claim 13, wherein: The linear actuator of the plunger clamping drive mechanism includes a plunger clamping motor and a screw mechanism, wherein the screw mechanism is used to convert the rotational motion of the plunger clamping motor into the axial motion of the plunger clamping plate.

15. The pipetting head according to claim 14, wherein: The screw mechanism of the plunger clamping drive mechanism includes a first sleeve and a second sleeve that are concentric and coupled by a threaded connection, wherein the second sleeve is fixed relative to the plunger mounting assembly, and wherein the plunger clamping motor is configured to rotate the first sleeve around the second sleeve to drive the axial movement of the plunger clamping plate.

16. The pipetting head according to claim 15, wherein: The threaded connection has a median diameter that is less than 30% of the width of the plunger clamping plate.

17. A pipetting head according to any one of claims 14 to 16, wherein: The screw mechanism of the plunger clamp drive mechanism is hollow and defines an axial bore in which a portion of the dispensing drive mechanism is received.

18. The pipetting head according to claim 17, wherein: The dispensing drive mechanism includes a ball screw actuator nut at least partially received within an axial bore of a screw mechanism of the plunger clamp drive mechanism.

19. A pipetting head according to claim 17 or claim 18, wherein: The screw mechanisms of the dispensing drive mechanism and the plunger clamping drive mechanism are concentric.

20. A pipetting head according to any one of claims 13 to 19, wherein: The plunger mounting assembly includes a plurality of plunger mountings, and wherein the plurality of plunger clamping members include a plurality of clamping rods, each of the clamping rods being coaxial with one of the plurality of plunger mountings and extending within the plunger mounting to limit inward movement of a plunger accommodated in the plunger mounting when the plunger clamping mechanism is engaged.

21. The pipetting head according to claim 20, wherein: The plunger mounting assembly further comprises a plunger mounting plate, and a plurality of the plunger mounting members are arranged on the plunger mounting plate.

22. A liquid dispensing device comprising: a body having a platform for receiving one or more microplates; as well as The pipetting head according to any one of claims 1 to 21, wherein the pipetting head is located above the platform.

Images