Pipette operation head for liquid dispensing device

Abstract

A pipette operating head (100) for a liquid dispensing device (10) for use with a plurality of removable pipettes (1010) is provided. The pipette operating head has a pipette body attachment assembly (120) for holding the pipette body (1100) of the removable pipette, a plunger attachment assembly (140) for holding the plunger (1200) of the removable pipette, and a dispensing drive actuator assembly (160) having a dispensing drive mechanism (162) for moving the plunger attachment assembly along a drive shaft. The pipette operating head also has a pipette body clamping mechanism (130) having a clamp drive mechanism (133) including a linear actuator (133), and a clamp drive link mechanism having at least one standoff (135) fixed to the clamping plate (125) and extending axially between the clamping plate and the actuator. The actuator axially moves at least one standoff to selectively engage the pipette body clamping mechanism.

Description

Technical Field

[0001] The present invention relates to a pipette operation head for a liquid dispensing device for use with a number of pipettes, each of which has a pipette body, or "pipette tip", and a plunger provided within the pipette body. The present invention relates in particular to a pipette body attachment assembly for holding the pipette body, a plunger attachment assembly for holding the plunger, a pipette body clamping mechanism capable of firmly holding the pipette body, and a dispensing drive mechanism for causing relative movement between the plunger and the pipette body attachment assembly.

Background Art

[0002] It is known to use pipettes for aspirating or dispensing liquid samples.

[0003] It is also known to use pipettes having a plunger provided in the pipette body. A typical pipette, known as a "volumetric" pipette, uses a plunger or piston to aspirate or dispense liquid either by direct contact with the sample liquid or via a small air gap. In use, the pipette body and plunger are both attached to the pipette operation head of a liquid dispensing device. The pipette operation head moves the plunger relative to the body and aspirates or dispenses liquid from the opening at the distal end of the pipette body. Such pipettes are used in automated machines and can improve the accuracy and reproducibility of pipette operation movements. Once the pipette operation movement is complete, the pipette body and plunger of the removable pipette are separated from the pipette operation head and can be replaced.

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

[0005] An improved pipette operation head is required.

Summary of the Invention

Means for Solving the Problems

[0006] A first aspect of the present invention is a pipette operation head for a liquid dispensing device for use with a number of pipettes, each of the number of pipettes having a pipette body and a plunger provided within the pipette body, the pipette operation head comprising a pipette operation head chassis, a pipette body attachment assembly for holding the pipette body, a plunger attachment assembly for holding the plunger, a dispensing drive actuator assembly operable to move the plunger attachment assembly relative to the pipette body attachment assembly along a drive shaft 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 mechanism coupling the dispensing drive motor to the plunger attachment assembly to cause its axial displacement, a pipette body clamping mechanism operable to selectively clamp the pipette bodies of the number of pipettes to the pipette body attachment assembly, a pipette body clamping plate positioned below the plunger attachment assembly, a plurality of pipette body clamping members on the pipette body clamping plate, A pipette body clamp drive mechanism operable to selectively engage a pipette body tightening mechanism, having a linear actuator and a pipette body clamp drive link mechanism, wherein the pipette body clamp drive link mechanism couples the linear actuator to a pipette body tightening plate, the pipette body clamp drive link mechanism being fixed relative to the pipette body tightening plate and comprising at least one standoff extending axially between the pipette body tightening plate and the linear actuator, the linear actuator being configured to move axially at least one standoff relative to a pipette operation head chassis to selectively engage the pipette body tightening mechanism, the pipette body clamp drive mechanism A pipette body tightening mechanism comprising Providing an operation head comprising

[0007] With this configuration, the linear actuator of the pipette body tightening mechanism can be positioned away from the pipette body tightening plate so as not to interfere with other movable parts of the pipette operation head. This can improve the packaging of the components within the pipette operation head. This is in contrast to configurations where the pipette body clamp is operated by a motor fixed to the side of the pipette body tightening plate. The configuration according to the claims can reduce the width of the pipette operation head and avoid interference between the actuator and components or equipment installed on the deck directly below the pipette operation head. Additionally, by providing at least one standoff between the linear actuator and the pipette body tightening plate, the present configuration can separate the rotational drive for the pipette body tightening plate from the means for guiding or moving the pipette body tightening plate. This has been found to reduce the risk of plate misalignment, or "crabbing", compared to configurations where rotational drive and guidance are provided by the same component, for example, a pulley nut connected to the tightening plate is rotated to move the plate along a threaded rod.

[0008] The pipetting operation head is configured for use with a number of pipettes, each having a pipette body and a plunger provided within the pipette body. The number of pipettes are a number of removable pipettes, each having a removable pipette body and a removable plunger. Accordingly, the plunger attachment assembly is for holding the removable plungers of the number of removable pipettes. This contrasts with some known pipetting operation heads where the plunger or "piston" remains fixed to the pipetting operation head, and the removable pipette consists only of a removable pipette tip. The use of a pipette with a removable plunger can help reduce the risk of cross - contamination of samples. According to 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 attachment assembly is configured to hold the pipette body in relation to the pipetting operation head, i.e., to connect and hold the pipette body to the pipetting operation head. The pipette body attachment assembly may be configured to hold the pipette body connector portion of each of the number of removable pipettes.

[0010] The plunger attachment assembly is configured to hold the plunger in relation to the pipetting operation head, i.e., to connect and hold the plunger to the pipetting operation head. The plunger attachment assembly may be configured to hold the plunger connector portion of each of the number of removable pipettes.

[0011] As used herein, the terms "clamping" and "clamp" refer to a configuration in which the pipette body or the plunger (or both) is attached and locked in place to prevent accidental removal. This is in contrast to a configuration in which the pipette body or the plunger is attached without locking, using, for example, an interference fit or snap-fit connection that can be easily removed by axially pulling on the pipette body or the plunger. The use of a clamping mechanism can also improve the accuracy of aspiration and dispensing operations by preventing small relative movements that can occur between the pipette operating head and the plunger or the pipette body.

[0012] As used herein, the term "standoff" refers to a spacer or other rigid component used to separate two parts in an assembly. At least one standoff maintains the spacing or separation between the pipette body clamping plate and the linear actuator and transmits axial drive to the pipette body clamping plate. At least one standoff may comprise a single standoff. Preferably, at least one standoff comprises a plurality of standoffs. The standoff may be connected to the central region of the pipette body clamping plate. Preferably, the plurality of standoffs are connected to the outer edge of the pipette body clamping plate. The plurality of standoffs may comprise two, three, or more standoffs. The plurality of standoffs may be positioned symmetrically around the outer edge of the pipette body clamping plate. The plurality of standoffs may comprise four standoffs. The four standoffs may each be connected to a corner of the pipette body clamping plate.

[0013] At least one standoff may have any suitable shape. At least one standoff may comprise at least one guide slot, along which the plunger attachment assembly is slidably supported when axially displaced by the dispensing drive actuator assembly.

[0014] At least one guide rod may comprise a plurality of guide rods, and along the plurality of guide rods, the plunger mounting assembly is slidably supported when axially displaced by the dispensing drive actuator assembly. The plurality of standoffs may be the plurality of guide rods, and along the plurality of guide rods, the plunger mounting assembly is slidably supported when axially displaced by the dispensing drive actuator assembly.

[0015] With this configuration, at least one guide rod serves a dual function of transmitting axial drive to a plurality of pipette body clamping members and providing a guide along which the plunger mounting assembly is slidably supported. As a result, there is no need to provide separate components to guide the movement of the plunger mounting assembly and transmit axial drive to the plurality of clamping members. This liberates space within the pipette operating head and allows the use of guide rods with a larger diameter without increasing the size of the pipette operating head. This can further improve the performance of the pipette operating head by reducing the amount of bending of the guide rods, thereby maintaining the parallel relationship between the moving plates. For example, the guide rods may each have a diameter of 8 mm to 14 mm, such as 10 mm or 12 mm. Further, by providing a single set of components that guide the movement of the plunger mounting assembly and transmit axial drive to the pipette body clamping members, the cumulative tolerances between the various moving parts of the pipette operating head are reduced. This facilitates the operation of the pipette operating head and can reduce the risk of misalignment. The plurality of guide rods may comprise two, three, four, or more guide rods. The plurality of guide rods may comprise four standoffs, each of which is connected to a corner of the pipette body clamping plate.

[0016] In some preferred embodiments, at least one standoff is slidably supported by a pipetting operation head chassis. Thereby, further, the rigidity of the moving parts can be improved and the risk of displacement can be reduced. The pipetting operation head chassis may include one or more linear bearings or bushings, whereby at least one standoff is slidably supported by the pipetting operation head chassis. The pipetting operation head chassis may include a plurality of linear bearings or bushings, whereby at least one standoff is slidably supported by the pipetting operation head chassis. The plurality of linear bearings are axially spaced apart and may slidably support at least one standoff at a plurality of locations along its length.

[0017] In some preferred embodiments, the linear actuator is located above the plunger mounting assembly. Thereby, the range in which the linear actuator does not interfere with other moving parts within the pipetting operation head can be further improved. In such embodiments, at least one standoff extends axially from directly below the plunger mounting assembly to above the plunger mounting assembly.

[0018] The linear actuator may comprise any suitable actuator. For example, the linear actuator may comprise a solenoid or a pneumatic or hydraulic actuating mechanism. In some preferred embodiments, 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 the axial movement of at least one standoff.

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

[0020] By arranging the dispensing drive mechanism and the screw mechanism of the pipette body clamp drive mechanism in the same location, this configuration can provide a compact structure. The linear actuator and the dispensing drive mechanism can both be located inboard of the plunger attachment assembly, i.e., they do not extend laterally beyond the edge of the plunger attachment assembly. This is in contrast to known mechanisms that utilize drive belts and pulleys located around the outer edges of the pipette and the plunger attachment mechanism. In such "outboard" mechanisms, the size of the pipette operation head typically has to be increased to accommodate the pulleys. The provision of the above-described compact pipette body clamp drive mechanism makes it easier to accurately and firmly attach a large number of pipettes to the pipette operation head. This is particularly useful in liquid dispensing devices intended for use with a standard 384-well plate, since a compact arrangement can be configured to hold 384 pipettes in, for example, a 16×24 matrix. Thereby, liquid can be aspirated from a conventional 384-well plate or dispensed into a conventional 384-well plate in a single operation.

[0021] The dispensing drive mechanism is laterally offset from the axis of the screw mechanism and extends through an axial hole. In some preferred embodiments, the dispensing drive mechanism and the screw mechanism are concentric. As used herein, the term "concentric" means that the dispensing drive mechanism and the screw mechanism are both aligned along a common axis and have a common center in a vertical plane along at least a portion of the length of the dispensing drive mechanism. In other words, the dispensing drive mechanism extends along a first axis, the screw mechanism is configured to rotate around a second axis, and 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 operate along the same single axis. Thereby, alignment of the forces applied by the dispensing drive mechanism and the pipette body clamping mechanism can be ensured, further helping to maintain the parallel relationship between the movable parts of the pipette operation head, further facilitating smooth operation, and reducing the risk of misalignment or lateral movement from uneven force application across the width of the plunger attachment assembly and / or the pipette body clamping mechanism.

[0023] With this configuration, the screw mechanism can also provide a single force to at least one standoff. This is in contrast to configurations where the pipette body clamping plate moves along multiple screw rods using belt drives and pulleys, and the pulleys need to be synchronized to ensure accurate alignment. According to this configuration, the screw mechanism is centered within the pipette operation head and can apply a single force centered on at least one standoff. Thereby, the ease of operation is further improved, and the risk of misalignment of the pipette body clamping plate can be further reduced.

[0024] In some preferred embodiments, the screw mechanism comprises a first sleeve and a second sleeve that are concentric. The first sleeve and the second sleeve may be coupled by a screw connection. The second sleeve may be fixed relative to at least one standoff. The pipette body clamp motor may be configured to rotate the first sleeve around the second sleeve, causing relative axial movement between the first sleeve and the second sleeve by the screw connection, thereby causing axial movement of at least one standoff.

[0025] One of the first sleeve and the second sleeve may be defined by an opening 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 pitch circle diameter of the screw connection is less than 40 percent of the width of the plunger attachment assembly, preferably less than 30 percent, less than 20 percent, less than 10 percent, or less than 5 percent of the width of the plunger attachment assembly. For example, the pitch circle diameter of the screw connection is 10 mm to 80 mm, 20 mm to 60 mm, or 30 mm to 50 mm.

[0027] In some preferred embodiments, the pipette body clamp motor is coupled to the screw mechanism by one or more gears. The screw mechanism may be coupled to a ring gear configured for rotation by the pipette body clamp motor. In other examples, the pipette body clamp motor may be coupled to the screw mechanism by any suitable means, such as by a toothed belt drive or by a worm drive.

[0028] In some preferred embodiments, the pipette body clamp motor is fixed to the pipette operation head chassis. The pipette body clamp motor may be fixed to the pipette operation head chassis. The pipette operation head chassis may include an upper head chassis portion where the pipette body clamp motor is mounted. The pipette body clamp motor may be positioned adjacent to the dispensing drive motor. This configuration results in a particularly compact configuration within the pipette operation head.

[0029] The pipette body attachment assembly is configured to hold the pipette body in an appropriate position relative to the pipette operation head. The pipette body clamping mechanism is configured to tightly clamp any existing pipette body to the pipette body attachment assembly. The pipette body clamping mechanism functions separately from the pipette body attachment assembly. While the pipette body attachment assembly holds the pipette body, the pipette body clamping mechanism ensures a firm fixation of the pipette body to the pipette body attachment assembly. This contrasts with a configuration where the pipette body is held in place by a single mechanism. For example, a configuration where the pipette bodies are arranged in a magazine that is held in place relative to the lower surface of the pipette operation head by a single mechanism. In such a configuration, such a mechanism might be considered an attachment assembly, by which the pipette bodies are held in relation to the pipette operation head. However, such a configuration does not have a clamping mechanism that is operable to selectively clamp the pipette body to the pipette body attachment assembly.

[0030] The pipette body attachment assembly may comprise a pipette body attachment plate having a plurality of pipette body mounts, each of the plurality of pipette body mounts being configured to engage with one of the pipette bodies during use. The pipette body attachment plate may be defined by the lower surface of the pipette operation head chassis. The pipette body clamping mechanism comprises a pipette body clamping plate, on which a plurality of pipette body clamping members are provided, each pipette body clamping member being associated with one of the plurality of pipette body mounts.

[0031] The pipette body clamping plate is positioned below the pipette body attachment assembly. The pipette body clamping plate may be the lowermost plate of the pipette operating head. As used herein, the terms "above", "upper", "low", "below", and "lowest" refer to the normal orientation of the pipette operating head during use. The plurality of pipette body clamping members may comprise a plurality of sleeves that define a clamping region. The plurality of pipette body clamping members may be coaxial with a plurality of pipette body mounts provided on the pipette body attachment assembly. The plurality of pipette body clamping members may surround the plurality of pipette body mounts when the pipette body clamping mechanism is engaged. The plurality of sleeves may be defined by one or more individual parts fixed to the pipette body clamping plate. In some preferred embodiments, the plurality of sleeves are defined by openings in the pipette body clamping plate itself. Each of the plurality of pipette body mounts may comprise a radially extending mechanism configured to form half of a snap-fit connection on its outer surface. The clamping region of each of the plurality of sleeves may be axially adjacent to the radially extending mechanism on the outer surface of the associated pipette body mount when the pipette body clamping mechanism is in the clamped position. The clamping region of each of the plurality of sleeves may be axially offset from the radially extending mechanism on the outer surface of the associated pipette body mount when the pipette body clamping mechanism is in the released position.

[0032] The dispensing drive actuator assembly may be a direct drive actuator assembly. In such embodiments, the dispensing drive mechanism is a direct drive mechanism. As used herein, the term "direct drive mechanism" refers to a drive mechanism in which the dispensing drive motor is directly coupled to the plunger mounting assembly or is coupled to the plunger mounting assembly via a rotary rigid coupling. Throughout this specification, the term "direct drive actuator" is used to refer to both a directly coupled configuration and a configuration in which the motor is coupled to the plunger mount assembly via a rotary rigid coupling. The use of a direct drive actuator minimizes the rotational movement between the plunger mount assembly and the motor. Thereby, the movement of the plunger mount assembly can 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 mount assembly via one or more belts or chains. Similarly, a clamp drive mechanism can directly couple a clamp motor to a plurality of clamp members, enabling the movement of the pipette clamping mechanism to be started and stopped quickly and accurately.

[0033] The dispensing drive motor may be a linear actuator configured to provide a translational motion 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 an axial movement of the plunger mounting assembly.

[0034] The dispensing drive mechanism may include a ball screw, which couples the drive motor to the plunger mounting assembly and causes axial movement of the plunger mount assembly. The dispensing drive mechanism preferably includes a drive shaft extending along the drive axis and a ball screw, by which the drive shaft is coupled to the plunger mount assembly.

[0035] The direct drive configuration has been found to provide a higher level of heavy load acceleration / deceleration than a belt drive system, for example via a ball screw, and thus enable non-contact dispensing of small liquid samples. Further, the direct drive configuration provides higher positional accuracy and reproducibility than an equivalent belt drive mechanism. This can have a significant impact on dispensing performance.

[0036] The drive actuator is operated completely independently of the pipette body clamping mechanism. By providing a drive actuator that is operated independently for dispensing or aspiration operations, more plunger speeds can be obtained and the pipette operation head can be accurately operated in both contact dispensing mode and non-contact dispensing mode. This contrasts with some known liquid handling devices where the pipette body and plunger are coupled to a plate positioned along a common series of threaded rods and only move relatively slowly with respect to each other along the common rod. Non-contact dispensing, also known as jetting, is characterized in that the liquid is dispensed from the pipette at a slight distance from the target such that the droplet leaves the tip of the pipette body before contacting the target. Contact dispensing is characterized in that the droplet is generated at the tip of the pipette body and deposited by contact with the target. When performing non-contact dispensing, the liquid sample must travel at a sufficiently fast speed and leave the tip. The distance the plunger travels for a dispensing shot is short and can be in the range of, for example, 1 mm or less. As a result, a high level of acceleration / deceleration is required to reach the target speed for non-contact dispensing.

[0037] By an independently operated drive actuator, a plunger mount assembly mechanism, and thus any plunger attached thereto, can move relative to the pipette body mount assembly and perform aspiration and dispensing operations independently of the pipette clamping mechanism. The distance the plunger advances for a dispensing shot can be short, for example, in the range of 1 mm or less. As a result, a high level of acceleration / deceleration is required to reach the target speed of non-contact dispensing. The independently operated drive actuator can be configured to accelerate and decelerate the plunger mount assembly at a sufficiently fast speed for both non-contact and contact dispensing enabled by the same mechanism.

[0038] The term "independently operated" refers to a configuration where the drive mechanism does not share any components with the pipette clamping mechanism. Thus, this drive mechanism is configured according to the desired acceleration and deceleration characteristics for dispensing and aspiration operations and does not have to conform to the desired clamping characteristics or form a compromise between those characteristics. This is in stark contrast to a configuration where the pipette body and plunger are attached to a plate arranged along a common threaded rod and all of the drive mechanisms, including the drive mechanism of the actuator controlling the dispensing operation, must operate at the same pitch of the thread. In this configuration, synchronization of the movement of the plate may also be required to perform the dispensing operation. This may require more complex control to ensure accurate dispensing and prevent clogging.

[0039] The plunger attachment assembly is a plunger clamping mechanism operable to clamp the plungers of a number of pipettes to the plunger attachment assembly, a plunger clamping plate, a plurality of plunger clamping members on the plunger clamping plate, and a plunger clamp drive mechanism operable to selectively engage the plunger clamping mechanism and comprises A linear actuator configured to cause relative axial movement between a plunger clamping plate and a plunger attachment assembly and selectively engage a plunger clamping mechanism comprises a plunger clamping mechanism having

[0040] The linear actuator may comprise any suitable actuator. For example, the linear actuator may comprise a solenoid or a pneumatic or hydraulic actuating mechanism. In some preferred embodiments, the linear actuator of the plunger clamp drive mechanism comprises a plunger clamp motor and a screw mechanism for converting the rotational movement of the plunger clamp motor into the axial movement of the plunger clamping plate.

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

[0042] Preferably, the pitch circle diameter of the screw connection of the plunger clamp drive mechanism is less than 40 percent, preferably less than 30 percent, 20 percent, 10 percent, or 5 percent of the width of the plunger clamping plate. For example, the pitch circle diameter of the screw connection may be 10 mm to 80 mm, 20 mm to 60 mm, or 30 mm to 50 mm.

[0043] In some preferred embodiments, the screw mechanism of the plunger clamp drive mechanism is hollow and defines an axial hole for receiving a portion of the dispensing drive mechanism. Thereby, it has been found that a particularly compact structure can be provided that reduces the overall height of the pipetting operation head.

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

[0045] The dispensing drive mechanism may be laterally offset from the axis of the screw mechanism and extend through the axial hole. In some preferred embodiments, the dispensing drive mechanism and the screw mechanism of the plunger clamp drive mechanism are concentric.

[0046] By arranging the dispensing drive mechanism and the screw mechanism concentrically, the dispensing drive mechanism and the screw mechanism operate along the same single axis. Thereby, the alignment of the forces applied by the dispensing drive mechanism and the plunger clamping mechanism can be ensured, and further, it helps to maintain the parallel relationship between the moving parts of the pipetting operation head, and further promotes smooth operation and reduces the risk of deviation or lateral movement from the uneven force application across the width of the plunger clamping mechanism. With this configuration, the screw mechanism is centered within the pipetting operation head and can apply the axial force applied to the plunger clamping plate centered. Thereby, the ease of operation is further improved, and the risk of misalignment of the plunger clamping plate can be further reduced.

[0047] In some embodiments, the plunger attachment assembly includes a plurality of plunger mounts, and the plurality of plunger clamping members each have a coaxial relationship with one of the plurality of plunger mounts and include a plurality of clamping rods extending within the plunger mount, and when the plunger clamping mechanism is engaged, restrict the inward movement of the plunger received within the plunger mount.

[0048] The plunger attachment assembly may further include a plunger attachment plate, on which a plurality of plunger mounts are provided.

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

[0050] According to a second aspect of the present invention, there is provided a liquid dispensing device comprising a body having a deck for receiving one or more microplates, and a pipetting head as described in the first aspect, the pipetting head being positioned on the deck.

[0051] The deck is configured to receive one or more microplates, but other experimental devices may be received on the deck instead of or in addition to the microplates. For example, not only a number of vials or sample tubes, liquid reservoirs, or any other experimental device used with the liquid dispensing device, but also one or more arrays of pipette bodies, well plates, or microplate movers may be received on the deck.

[0052] A pipetting head for a liquid dispensing device for use with a number of removable pipettes, each of the number of removable pipettes having a pipette body and a plunger provided within the pipette body, the pipetting head comprising a pipetting head chassis, a pipette body attachment assembly for holding the pipette body, a plunger attachment assembly for holding the plunger, A dispensing drive actuator assembly that is operable to move a plunger attachment assembly relative to a pipette body attachment assembly along a drive shaft to perform a dispensing or aspiration operation, the dispensing drive actuator assembly comprising a dispensing drive motor and a dispensing drive mechanism, wherein the dispensing drive mechanism couples the dispensing drive motor to the plunger attachment assembly to cause an axial displacement thereof. A pipette operating head is also disclosed that includes a plunger clamping mechanism operable to clamp the plungers of a plurality of pipettes to the plunger attachment assembly. The plunger clamping mechanism includes a plunger clamping plate, a plurality of plunger clamping members on the plunger clamping plate, and a plunger clamp drive mechanism operable to selectively engage the plunger clamping mechanism. The plunger clamping mechanism causes relative axial movement between the plunger clamping plate and the plunger attachment assembly and has a linear actuator configured to selectively engage the plunger clamping mechanism.

[0053] Further features and advantages of the present invention are described below by way of example only with reference to the accompanying drawings.

Brief Description of the Drawings

[0054]

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Mode for Carrying Out the Invention

[0055] FIG. 1 shows a liquid dispensing device 10 for use with a number of positive displacement pipettes 1010. The device 10 comprises a body 12 having a microplate receiving area or deck 14 and a pipette operating head 100 positioned above the microplate receiving area 14. The microplate receiving area 14 has a substantially horizontal upper surface 16 arranged to receive a laboratory microplate. The receiving area 14 may be located on an adjustable height support structure 18 that can change the height of the microplate receiving area 14 as required. The receiving area 14 may be configured to hold the laboratory microplate in a fixed position. For example, the upper surface 16 of the receiving area 14 may comprise one or more recesses (not shown) arranged to receive the microplate and prevent lateral movement of the microplate relative to the receiving area 14. The device 10 is typically used in the orientation shown in FIG. 1, with gravity holding the product within the wells of the microplate. The axis marked Z in FIG. 1 therefore represents the upward direction, and the gravity acting in the opposite direction holds the product within the wells of the microplate. References to upward and downward directions or axial directions therefore refer to movement along the axis marked Z in FIG. 1. On the other hand, references to lateral or transverse directions refer to movement in the directions marked X (width) and Y (depth) in FIG. 1. References to vertical direction or height also therefore refer to dimensions or movement along the axis marked Z in FIG. 1. The pipette operating head 100 is configured to hold a number of pipettes, as shown below in connection with FIGS. 2 - 21, is movable relative to the deck 14, and may bring a pipette attached to the pipette operating head 100 close to a microplate supported on the deck 14 so that liquid is aspirated from or dispensed into the wells of the microplate.

[0056] Figure 2 is a perspective view of the pipetting operation head 100. The pipetting operation head includes a head chassis 101 having an upper head chassis portion 102, a lower head chassis portion 103, and an intermediate head chassis portion 104 between the upper and lower head chassis portions. All of them are fixed together to form the main body of the pipetting operation head 100. The top cover 105 may be removably attached on top of the top surface of the upper head chassis portion 102. The head chassis 101 is connected to the main body of the apparatus by a chassis support plate (not shown). The chassis support plate can preferably move the entire pipetting operation head 100 in the X, Y, and Z directions with respect to the receiving area of the apparatus in a conventional manner using one or more head actuators (not shown).

[0057] Figure 3 is a perspective view of the pipetting operation head 100 with the top cover removed, and Figure 4 is an exploded view of the head chassis components of the pipetting operation head 100. The upper head chassis portion 102 forms supports on its top surface for the dispensing drive motor 161 of the dispensing drive actuator assembly 160 of the pipetting operation head 100 and for the pipette body clamp motor 132, which will be described in more detail below. The control circuit 106 for the operation of the pipetting operation head is also fixed to the top surface of the upper head chassis portion 102. All the components attached to the top surface of the upper head chassis portion 102 may be enclosed under the top cover 105 when the top cover 105 is installed on the upper head chassis portion 102. The intermediate head chassis portion 104 includes an outer wall 107 having a rectangular cross-sectional shape. The outer wall 107 has openings 110 at each of its four corners. Each opening 110 may include a linear bushing 115. The lower head chassis portion 103 has an outer wall 111 that defines an internal chamber 112 and has a rectangular cross-sectional shape similar to that of the upper head chassis portion 102 and the intermediate head chassis portion 104. The outer wall 111 has openings 113 at each of its four corners. Each opening 113 may include a linear bushing 116.

[0058] During use, the pipetting operation head 100 further includes a pipette body attachment assembly 120 for holding the pipette bodies of a number of volumetric pipette bodies. The pipette body attachment assembly 120 includes a pipette body attachment plate (identified as mechanism 121 in FIG. 6) formed integrally with or fixed to the lower surface of the lower head chassis portion 103. The upper head chassis portion 102, the lower head chassis portion 103, and the intermediate head chassis portion 104 may be fixed together in any suitable manner, for example, using bolts and tie rods.

[0059] FIG. 5 is a cross-sectional view of the pipetting operation head 100 with the upper and intermediate head chassis portions removed for clarity. During use, the pipetting operation head 100 further includes a plunger attachment assembly 140 for holding the plungers of a number of volumetric pipette bodies. The pipetting operation head 100 also includes a pipette body clamping mechanism 130 for tightly clamping the pipette body to the pipette body attachment assembly 120. In the present embodiment, the pipetting operation head 100 also includes a plunger clamping mechanism 150 for tightly clamping the plunger to the plunger attachment assembly 140. In other embodiments, the pipetting operation head may include only one of the two pipette clamping mechanisms. The pipetting operation head 100 also includes a dispensing drive actuator assembly 160 that is operable to axially move the plunger attachment assembly 140 relative to the pipette body attachment assembly 120 and perform a dispensing or aspiration operation with a number of pipettes attached to the pipetting operation head 100.

[0060] With reference to FIGS. 5 to 12, the pipette body attachment assembly 120 and the plunger attachment assembly 140, the pipette body clamping mechanism 130 and the plunger clamping mechanism 150, and the dispensing drive actuator assembly 160 will be described in more detail.

[0061] As best seen in FIGS. 5 - 7, the pipette body clamping mechanism 130 includes a pipette body clamp plate 125 positioned below the pipette body attachment plate 121, and a pipette body clamp drive mechanism 133 including a linear actuator and pipette body clamp drive link mechanisms 134, 135. The linear actuator is fixed to the head chassis 101 and includes a pipette body clamp motor 132 coupled to the pipette body clamp plate 125 by the pipette body clamp drive link mechanisms 134, 135. When the pipette body clamp motor 132 is actuated, it moves the clamp plate 125 axially to selectively engage the pipette body clamping mechanism 130. The pipette body clamp motor 132 is fixed to the top surface of the upper head chassis portion 102. The pipette body clamp drive link mechanism includes a bearing plate 134 coupled to the linear actuator, and a plurality of standoffs 135 extending between the bearing plate 134 and the pipette body clamp plate 125. The linear actuator is further coupled to the bearing plate 134 and includes a screw mechanism 136 configured to convert the rotation of the clamp motor 132 into an axial displacement of the standoffs 135 and the clamp plate 125. In the present embodiment, the standoffs are provided in the form of guide rods 135 whose upper ends are radially supported by the linear bushings 115 of the intermediate head chassis portion (mechanism 104 in FIG. 4) and whose lower ends are radially supported by the linear bushings 116 of the lower head chassis portion (mechanism 103 in FIG. 4). The guide rods 135 are also radially supported between their upper and lower ends by linear bushings 173 provided at each of the four corners of the plunger attachment assembly 140. In the present embodiment, there are four guide rods, one at each corner of the clamp plate 125. In other embodiments, fewer or more guide rods or standoffs may be provided. For example, the plurality of standoffs may consist of two standoffs positioned on both sides of the clamp plate 125, for example, at the midpoint between the front and back of the clamp plate 125.

[0062] The screw mechanism 136 includes a ring gear 137 coupled to the bearing plate 134 by screw connection (see FIG. 7). The ring gear 137 is supported by a bearing 131 provided between the upper head chassis portion 102 and the ring gear 137. In this way, the ring gear 137 is fixed axially with respect to the head chassis 101 and is rotatable around the drive shaft 190. The clamp 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 axially, i.e., along the drive shaft 190, and a radial flange 137B having a plurality of gear teeth 137C. The radial flange 137B may extend radially outward from the hollow shaft 137A. In the illustrated embodiment, the hollow shaft 137A of the ring gear 137 extends within the screw hole 134A of the bearing plate 134, and the screw connection between the ring gear 137 and the bearing plate 134 is provided by the screw threads on the outer surface of the hollow shaft 137A of the ring gear 137 and the complimentary screw threads on the inner surface of the screw hole 134A of the bearing plate 134. The holes of the bearing plate 134 and the hollow shaft 137A both define a central opening or an axial hole. In other embodiments, the bearing plate 134 may include a hollow shaft 134A extending within the hole of the hollow shaft 137A of the ring gear 137, and the screw connection is provided by the screw threads on the outer surface of the hollow shaft 134A of the bearing plate 134 and the complimentary screw threads on the inner surface of the hollow shaft 137A of the ring gear 137.

[0063] When the clamp motor 132 is operated, the drive gear 138 rotates the ring gear 137, whereby the bearing plate 134 moves axially relative to the ring gear 137 by a screw connection between the ring gear 137 and the bearing plate 134. Rotation of the clamp motor 132 in the first direction causes the bearing plate 134 to move axially upward. Rotation of the clamp motor 132 in the opposite, second direction causes the bearing plate 134 to move axially downward. Since the bearing plate 134 is fixed to the clamp plate 125 by the guide rod 135, the clamp plate 125 moves axially together with the bearing plate 134, moves toward the pipette body mounting plate 121, or moves away from the pipette body mounting plate 121. With this configuration of the guide rod, the plunger attachment assembly 140 can slide axially along the guide rod when the plunger attachment assembly 140 is moved by the dispensing drive actuator assembly, and the guide rod can move axially along the linear bush when the pipette body clamping mechanism 130 is operated. In this way, the standoff serves a dual function of transmitting axial drive from the bearing plate 134 to the clamp plate 125 and providing a guide along which the plunger attachment 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 attachment assembly 140. Due to the dual function of the guide rod 135, there is no need to provide separate components to guide the movement of the plunger attachment assembly 140 and to transmit the axial displacement of the bearing plate 134 to the pipette body clamp plate 125. This liberates the space within the head chassis 101, while increasing the diameter of the guide rod 135 used, and still maintaining a compact structure within the pipette operation head. This can further improve the performance of the pipette operation head by reducing the amount of bending of the guide rod and thereby maintaining the parallel relationship between the moving plates. For example, the diameter of the guide rod 135 may be 8 mm to 16 mm, for example, 12 mm.

[0064] Figure 8 is an enlarged cross-sectional view of the pipette body mounting plate 121 and the pipette body clamping plate 125. The pipette body attachment plate 121 has a number of openings 122 that extend axially through the thickness of the pipette body attachment plate 121. When fixed within each opening 122, the pipette body mount 123 extends axially downward from the plate 121 and is configured to couple with one of the pipette bodies during use. Each pipette body mount 123 is in the form of a tubular pipette body mount sleeve held within one of the number of openings 122. In this example, each opening 122 has a restriction portion having a diameter less than the outer diameter of the pipette body mount sleeve. The restriction portion prevents the pipette body mount sleeve 123 from being pushed upward through the pipette body attachment plate when the pipette body mount sleeve is first inserted into the pipette body. The upper end of the pipette body mount sleeve 123 preferably has an inwardly tapered end face to assist in the insertion of components of the plunger clamping mechanism into the hole of the pipette body mount sleeve 123. The lower end of the pipette body mount sleeve 123 preferably has an outwardly tapered end face to assist in the insertion of the lower end of the pipette body mount sleeve into the pipette body. The outer surface of each pipette body mount sleeve 123 is provided with a radially extending mechanism configured to form half of a snap-fit connection with a mechanism formed on the inner surface of the pipette body corresponding thereto. In this example, the radially extending mechanism is in the form of an annular groove 124 surrounding the pipette body mount sleeve 123.

[0065] The pipette body clamping plate 125 has a number of openings 126 that extend axially through the thickness of the pipette body clamping plate 125. The number and position of the number of openings 126 correspond to the number of openings 122 in the pipette body mounting plate 121. The pipette body clamping plate 125 further comprises a number of pipette body clamping members 127, each of which is associated with one of the plurality of pipette body mounts 123. In this example, the number of pipette body clamping members 127 is provided in the form of a plurality of clamp sleeves 127 defined by an area of the pipette body clamping plate 125 that directly surrounds the opening 126 defined within the pipette body clamping plate 125. Each clamp sleeve 127 has a clamping area 128 with an inner diameter that is larger than the outer diameter of its respective pipette body mount sleeve. In this way, as shown in FIG. 8, when the pipette body clamping mechanism 130 is engaged, a small gap is provided between the outer surface of the pipette body mount sleeve 123 and the inner surface of the clamping area 128. The pipette body clamp plate 125 is moved by the pipette body clamp drive mechanism 133 between an engaged state and a released or "liberated" state.

[0066] When the clamp plate 125 is positioned against or near the lower surface of the pipette body mounting plate 121, the clamp sleeve 127 is axially offset from the annular groove 124 of the pipette body mount 123. This is the released state, at which time the pipette body can be placed on the pipette body mount 123 or removed from the pipette body mount 123 without interference from the clamp plate 125. To engage the pipette body clamping mechanism, the clamp plate 125 moves axially away from the pipette body mounting plate 121 until the clamping region 128 of the clamp sleeve 127 is adjacent to the annular groove 124 of the pipette body mount 123. This is the engaged state, at which time the clamp sleeve resists or prevents removal of the pipette body from the pipette body mount 123 by preventing separation of the snap-fit connection between the pipette body and the pipette body mount 123.

[0067] Each clamp sleeve may have a substantially constant inner diameter. Alternatively, each clamp sleeve may have regions of different inner diameters, as shown in FIG. 8. By way of example, each clamp sleeve 127 has a narrow region 129A towards its upper end and a tapered region 129B at its bottom end. The inner diameter of the clamp sleeve 127 decreases in the tapered region 129B from the lowermost tip to the clamping region 128. With this configuration, one or more pipette bodies can be semi-fixed by being positioned in an intermediate “pre-lock” position in the pipette body clamping plate 125 where the tapered region 129B of the clamp sleeve 127 is adjacent to a recess or annular groove 124 on the outer surface of the pipette body mounting sleeve 123. This can facilitate the picking of a portion of the plurality of bodies from the box. Once the picked body is lifted above the plurality of unpicked bodies, the picked pipette body can subsequently 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 clamp sleeve 127 and the outer surface of the pipette body mount 123. This can serve to minimize the force required to move the pipette body clamping plate 125 axially and facilitate the smooth operation of the pipette body clamping mechanism 130.

[0068] FIG. 9 is a cross-sectional view of the plunger attachment assembly 140 and the plunger clamping mechanism 150. The plunger attachment assembly 140 and the plunger clamping mechanism 150 are both movable axially together by a dispensing drive actuator assembly 160. The plunger clamping mechanism 150 is axially movable relative to the plunger attachment assembly 140.

[0069] As best seen in FIGS. 9-11, the plunger attachment assembly 140 includes a plunger attachment plate 141 having a plurality of openings 142. The plunger attachment assembly 140 includes a box-shaped housing 170 in which components of the plunger attachment assembly 140 and the plunger tightening mechanism 150 are at least partially received. For simplicity of the assembly, the housing 170 preferably has a two-part structure including an upper housing and a lower housing that are both fixed around the plunger tightening mechanism 150. The plunger attachment plate 141 forms the lower surface of the housing 170. The housing 170 is rectangular in cross-sectional shape and includes linear bushings 173 extending axially at each corner. The linear bushings 173 are supported within the openings 174 of the housing 170 such that the entire assembly shown in FIG. 9 can move up and down along the guide rods of the pipette body tightening mechanism.

[0070] The plunger clamping mechanism 150 includes a plunger clamping plate 145 positioned on the plunger mounting plate 141, a plurality of plunger clamping members 147 (see FIG. 11) on the plunger clamping plate 145, and a plunger clamp drive mechanism 153 operable to selectively engage the plunger clamping mechanism. The plunger clamp drive mechanism includes a linear actuator 153 configured to cause relative axial movement between the plunger clamping plate and the plunger mounting assembly and to selectively engage the plunger clamping mechanism. The linear actuator 153 includes a plunger clamp motor 152 fixed to the plunger clamping plate 145 and coupled to the plunger mounting assembly 140. When the clamp motor 152 is actuated, it moves the plunger clamping plate 145 axially relative to the plunger mount plate 141 to selectively engage the plunger clamping mechanism 150. The plunger clamping mechanism 150 further includes a plunger clamp support plate 154 and a motor support plate 154A fixed to the plunger clamp support plate 154. The plunger clamping plate 145 is fixed to the lower surface of the plunger clamp support plate 154. The plunger clamping mechanism may further include a plunger clamp guide slot 155 for guiding the plunger clamping plate 145 during movement of the plunger clamping mechanism 150. In the present embodiment, the plunger clamp guide slot 155 is fixed to the plunger clamp support plate 154 and slides within an opening 175 of a housing 170 located inside the opening 174. In other embodiments, the plunger clamp guide slot may be fixed to the housing 170 and the support plate may include an opening for sliding along the outside of the guide slot.

[0071] The plunger clamp drive mechanism 153 includes a screw mechanism 156 configured to convert the rotation of the clamp motor 152 into an axial displacement of the clamp plate 145. The screw mechanism 156 includes a ring gear 157 and a hollow shaft 176 that are coupled together by a screw connection. The hollow shaft 176 extends along the drive shaft 190 and is fixed to the housing 170 of the plunger attachment assembly 140. The ring gear 157 is supported by a bearing 151 provided between the plunger clamp support plate 154 and the ring gear 157. In this way, the ring gear 157 is axially fixed relative to the plunger clamp support plate 154 and is rotatable around the drive shaft 190. The ring gear 157 includes an axial hole 157A that extends axially, that is, along the drive shaft 190, and a radial flange 157B having a plurality of gear teeth 157C. The radial flange 157B may extend radially outward from the hollow shaft 157A. The holes of the hollow shaft 176 and the ring gear 157 together define a central opening or an axial hole. In the illustrated embodiment, the hole 157A of the ring gear 157 extends around the hollow shaft 176 fixed to the housing 170, and the screw connection between the ring gear 157 and the hollow shaft 176 is provided by the external thread of the hollow shaft 176 and the complementary internal thread of the hole 157A of the ring gear 157. In other embodiments, the ring gear 157 may include a threaded shaft extending within the hole of the hollow shaft 176 of the housing 170, and the screw connection is provided by the external thread of the hollow shaft of the ring gear 157 and the complementary internal thread of the hollow shaft 176.

[0072] The clamp motor 152 drives the drive gear 158, the teeth of which engage with the teeth 157C of the ring gear 157. When the clamp motor 152 is operated, the drive gear 158 rotates the ring gear 157 around the hollow shaft 176. Due to the screw 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 the hollow shaft 176 axially up and down. Due to the axial fixation of the ring gear 157 to the plunger clamp support plate 154, the axial movement of the ring gear 157 causes axial movement of the other parts of the plunger clamping mechanism 150 except for the hollow shaft 176 which is fixed to the housing 170. Rotation of the clamp motor 152 in the first direction causes the ring gear 157 to move axially upward along the hollow shaft 157. Rotation of the clamp motor 152 in the opposite, second direction causes the plunger clamping mechanism 150 to move axially downward. Since the clamp plate 145 is fixed to the plunger clamp support plate 154, the clamp plate 145 moves axially together with the plunger clamp support plate 154, moving towards or away from the plunger mount plate 141.

[0073] FIG. 11 is an enlarged cross-sectional view of a portion of the plunger attachment assembly 140 and the plunger clamping mechanism 150, showing the plunger attachment plate 141 and the plunger clamp plate 145 in more detail. The plunger attachment plate 141 has a number of openings 142 that extend axially through the thickness of the plunger attachment plate 141. Fixed within each opening 142, the plunger mount 143 extends axially downward from the plate 141 and is configured to couple with one of the plungers during use. Each plunger mount 143 is in the form of a tubular plunger mount sleeve held in one of the number of openings 142. In this example, the plunger mounts 143 each have an outer diameter larger than the diameter of the opening 142 and have a shoulder that abuts against the lower surface of the plunger mount plate 141. The shoulder serves to set the height of the plunger mount sleeve 143 when first inserted into the opening 142 in the plunger mount plate 141. The lower end of the pipette body mount sleeve 143 preferably has a tapered end face on the inside to assist in the insertion of the plunger into the hole of the plunger mount sleeve 143. Each plunger mount sleeve 143 is provided on its inner surface with a radially extending mechanism configured to form half of a snap-fit connection with a correspondingly shaped mechanism on the outer surface of the plunger. In this example, the radially extending mechanism is in the form of an annular groove 144 on the inner surface of the plunger mount sleeve 143 that faces the lower end.

[0074] The plunger clamping plate 145 has a number of depressions or openings 146 extending axially. The number and position of the number of openings 146 in the plunger clamping plate 145 correspond to the number of openings 142 in the plunger mounting plate 141. The number of openings 146 in the plunger clamping plate 145 may correspond in number to the number of openings 122 and 126 of the pipette body mounting and clamping mechanism. The plunger clamping plate 145 further comprises a number of plunger clamping members 147, each associated with one of a plurality of plunger mounts 143. The number of plunger clamping members are provided in the form of a plurality of clamping rods 147 extending axially from the plunger clamping plate 145 and extending into a hole defined within the plunger mount sleeve 143. Each clamping rod 147 has, at its lower end, an enlarged head 148 extending from a narrower neck region 149A. The enlarged head 148 has an outer diameter less than the inner diameter of the plunger mount sleeve 143. In this way, when the plunger clamping mechanism is engaged, a small gap is provided between the outer surface of the enlarged head 148 and the inner surface of the plunger mount sleeve 143. The neck 149A has an outer diameter less than the outer diameter of the enlarged head 148. Preferably, each clamping rod 147 also has a spindle 149B having an outer diameter substantially the same as the inner diameter of the region of the plunger mount sleeve 143 in which it is located. Since the plunger clamping plate 145 moves axially up and down relative to the plunger mount plate 141, the spindle 149B moves axially along the hole in the plunger mount 143.

[0075] By the relative movement between the plunger tightening plate 145 and the plunger mounting plate 141, the plunger can be moved to any position between the engaged state where the plunger is tightened at an appropriate position and the released or "liberated" position or state where the plunger is axially connected to or removed from the plunger mount. The plunger tightening mechanism 150 can be moved. The plunger tightening mechanism 150 may be configured to move to the withdrawn state where the plunger tightening plate 145 is moved beyond the tightening position to the plunger mounting plate 141. In this position, the enlarged head 148 of the tightening rod 147 is axially below the mechanism extending radially of the inner surface of the plunger mount sleeve 143, and the mechanism extending radially is instead in line with the narrower neck portion 149A of the tightening rod. Thereby, the top of the plunger, i.e., the plunger connector portion, can be bent inward. By further downward movement of the tightening plate 145 and the tightening rod 147, the plunger is pushed downward and the plunger is released from the snap-fit connection with the plunger mounting sleeve. When the pipette body tightening plate 125 is also in the released position, further downward movement of the tightening rod using the plunger tightening drive mechanism presses the plunger against one or more inner surfaces of the pipette body, for example, the area around the opening at the distal end of the pipette body, and the pipette body is pushed out from the pipette body tightening mechanism. Thereby, the entire pipette assembly is removed from the pipette operating head. Alternatively, the direct drive actuator 160 may be used to move the tightening rod and the plunger downward together, press against the pipette, and thereby remove the pipette body from the device. In this removal mode, the plunger may remain in the device after the pipette body has been removed.

[0076] As best seen in FIG. 12, the dispensing drive actuator assembly 160 includes a dispensing drive motor 161 and a dispensing drive mechanism 162. By means of the dispensing drive mechanism 162, the dispensing drive motor 161 is directly coupled to the plunger attachment assembly 140, causing its axial displacement. The dispensing drive motor 161 is mounted on the top surface of the upper head chassis portion 102. The dispensing drive mechanism 162 includes an output shaft 165 of the dispensing drive motor 161, a lead screw 163, and a ball screw actuator nut 164. Together with the ball screw actuator nut 164, the lead screw 163 forms a ball screw actuator. The output shaft of the drive motor 161 may be integral with, i.e., an assembly with, the lead screw 163 or an individual component fixed to the lead screw 163 for rotation. The ball screw nut 164 is axially fixed relative to the plunger attachment assembly 140, and the two move simultaneously along the lead screw 163 when the lead screw 163 rotates. In the illustrated embodiment, the ball screw nut 164 is fixed within the hollow shaft 176 of the housing 170 of the plunger attachment assembly 140.

[0077] The lead 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 these components are aligned along a common axis. The output shaft 165 of the drive motor 161 and one or both of the lead screw 163 extend through an axial hole defined by the screw mechanism 136 of the pipette body clamping mechanism. One or both of the lead screw 163 and the ball screw nut 164 may extend through an axial hole defined by the screw mechanism 156 of the pipette body clamping mechanism. Thus, 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.

[0078] With this configuration, all the forces applied by various drive mechanisms preferably act along the same, central, single axis. This can help to keep the movable plates parallel to each other, facilitate smooth operation, and reduce the risk of lateral movement. Further, each drive mechanism applies force at a single location. This avoids the risk of lateral movement due to the application of non-uniform forces at multiple locations. For example, if forces are applied to each of the four corners of a plate by a pulley and belt configuration, if the forces at each pulley cannot be maintained uniformly, it may lead to lateral movement of the plate.

[0079] Referring to FIG. 5, when the dispensing drive actuator assembly 160 is operated, the entire plunger attachment assembly 140 moves axially along the guide rod 135 either towards or away from the pipette body attachment assembly 120 depending on the direction of rotation of the dispensing drive motor 161. The linear bush 173 slides along the outer surface of the guide rod 135, and the plunger held by the plunger attachment assembly 140 can be accelerated quickly and accurately with respect to the pipette body in which the plunger extends, independent of the limitations 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 jetting - liquid is dispensed from the pipette at a short distance from the target so that the droplet leaves the tip of the pipette body before contacting the target) and a contact dispensing mode (a droplet is formed at the tip of the pipette body and deposited by contact with the target). When performing non-contact dispensing, the liquid sample must travel at a sufficiently high speed and leave the tip. The distance the plunger travels for a dispensing shot can be short, for example, in the range of 1 mm or less. As a result, a high level of acceleration / deceleration is required to reach the target speed for non-contact dispensing. The linear bush 173 aligns the mating parts of the pipette operating head assembly and minimizes the stacking tolerances. Additionally, the use of a linear bush has been found to be a very effective way to maintain the perpendicularity or parallel relationship between the plunger attachment assembly, the pipette body attachment assembly, and the pipette body clamping mechanism. For example, a direct drive configuration via a ball screw provides a higher level of heavy load acceleration / deceleration than a belt drive system, thus enabling non-contact dispensing of small liquid samples. Furthermore, the direct drive configuration can provide higher positional accuracy and reproducibility than an equivalent belt drive mechanism. This can have a significant impact on the dispensing performance.

[0080] Thus, 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.

[0081] Figures 13 to 17 show a pipette 1010 for use with the pipetting operation heads of Figures 2 to 12. The pipette 1010 includes a pipette body 1100 and a plunger 1200.

[0082] The pipette body 1100 may be a receptacle that receives and / or contains a sample fluid or sample liquid. The pipette body 1100 may be configured to be inserted into a container of the sample liquid or into the sample liquid. The pipette body 1100 has a proximal end 1101 and a distal end 1102, and the proximal end 1101 and the distal end 1102 define a longitudinal axis 1001 extending therebetween. The pipette body 1100 has an opening 1108 at its distal end 1102, as shown in FIG. 15. The opening 1108 may be defined by the 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 opening 1108 may be of any suitable shape, such as elliptical, oval, or circular. The pipette body 1100 has a fluid cavity 1109 that extends at least partially from the opening 1108 towards the proximal end 1101. The fluid cavity is 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 the 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 provided. The longitudinal axis 1001 may define a central axis around which the pipette body 1100 and / or the plunger 1200 are provided uniformly or symmetrically around. The pipette body 1100 and / or the plunger 1200 may be configured such that the direction of aspiration and / or dispensing is along the longitudinal axis 1001. The pipette body 1100 may be substantially elongated and extend between its proximal end 1101 and its distal end 1102. The pipette body 1100 may be substantially or completely hollow. The pipette body 1100 may comprise or consist of a polymeric material. The pipette body 100 may comprise or consist of a homogeneous material. The pipette body 100 may comprise or consist of a translucent or transparent material.

[0083] The pipette body 1100 may comprise a series of parts, each having a different function, prominent feature, and / or different shape or dimensions. The pipette body 1100 may comprise one or more of, for example, a pipette body connector portion 1103, a central portion 1104, a support portion 1105, a body portion 1106, and a bridging portion 1107, as shown in FIG. 15. From the proximal end 1101 to the distal end 1102, the parts may be arranged in the order of the pipette body connector portion 1103, the central portion 1104, the support portion 1105, the body portion 1106, the bridging portion 1107, and the end portion 1110. The fluid cavity 1109 may extend through one, a plurality, or all of the parts of the pipette body 1100. The plunger 1200 may extend through one, a plurality, or all of the parts of the pipette body 1100.

[0084] The pipette body connector portion 1103 is configured to be connected to a liquid handling system, for example, by a snap-fit connection. The pipette body connector portion 1103 may comprise a split tubular wall 1120 that may be defined by a plurality of flexible segments 1121. The flexible segments 1121 are elastically deflected in the radially outward direction, and the outer diameter of the proximal end 1101 of the pipette body 1100 is configured to increase from a first outer diameter where the flexible segments are not deflected and the pipette body connector portion is in a stationary state to a second outer diameter where the flexible segments are deflected radially outward and the pipette body connector portion is in an expanded state. In the depicted embodiment, the pipette body connector portion 1103 comprises four axially extending cuts or slots 1122 in the tubular wall 1120 that demarcate the four flexible segments 1121. The pipette body connector portion 1103 may comprise any suitable number of axially extending cuts 1122 and may define any number of flexible segments 1121, such as two, three, four, five, or six. The configuration of the flexible segments 1121 and the slots 1122 allows the pipette body connector portion to be expanded without applying a large force to the pipette body connector portion. This can reduce the insertion force required to engage the pipette body connector portion 1103 with the pipette operating head.

[0085] The pipette body connector portion 1103 may further include one or more radially extending mechanisms 1123 on its inner surface, whereby the pipette body can be connected to the pipette operation head. The radially extending mechanism on the inner surface of the pipette body connector portion 1103 may include protrusions extending radially inward and / or depressions or grooves extending radially outward. The radially extending mechanism may extend circumferentially. In the described embodiment, the radially extending mechanism on the inner surface of the pipette body connector portion 1103 includes a partial 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 expands is larger than the first outer diameter by at least the radial range of the radially extending mechanism 1123. The rib 1123 preferably has an angled upper surface and a lower surface, and along the upper surface and the lower surface, the inner diameter of the pipette body connector portion gradually increases from the rib 1123 to the regions of the pipette body connector portion above and below the rib 1123. The angle of the upper surface can be selected according to the desired insertion force. The angle of the lower surface can be selected according to the desired extraction force. The upper surface or the lower surface may each have an angle of 10 to 80 degrees, for example, 20 to 70 degrees, 30 to 60 degrees, or 40 to 50 degrees from the axial direction of the pipette body.

[0086] The central portion 1104 may be configured to be centered on the plunger 1200 within the pipette body 1100. The central portion 1104 may have an inner surface that may be tapered or conical in shape. The support portion 1105 may comprise one or more structural ribs or rings configured to reduce the flexibility of the pipette body 1100 and / or improve the structural integrity. The one or more ribs may extend along at least a portion of the length between the proximal end 1101 and the distal end 1102, for example, axially, on the outer surface of the pipette body, as best seen in FIG. 16. The body portion 1106 may be substantially cylindrical and / or elongated. The body portion 1106 may have a substantially uniform inner diameter and / or outer diameter. The body portion 1106 may extend along at least half of the length of the pipette body 1100. The body portion 1106 may have an inner diameter and / or outer diameter greater than any diameter of the end portion 1110. The bridging portion 1107 may be configured to bridge the body portion 1106 to the end portion 1110. The bridging portion 1107 may define a gradual transition or step between the body portion 1106 and the end portion 1110. The bridging portion 1107 may be substantially tapered, conical, and / or dome-shaped.

[0087] The plunger 1200 has a proximal end 1201 and a distal end 1202 and extends along the longitudinal axis 1101. The plunger 1200 is configured to extend at least partially between the proximal end 1101 and the distal end 1102 of the pipette body 1100 and into the end portion 1110. The plunger 1200 may be configured to extend substantially or fully between the proximal end 1101 and the distal end 1102 of the pipette body 1100 and into the end portion 1110. The plunger 1200 is movable toward and away from the opening 1108 to aspirate fluid or dispense fluid from the pipette body 1100. The plunger 1200 may have an end outer wall surface 1212 configured to be aligned with the inner wall surface 1111 of the pipette body end portion 1110. The plunger 1200 may comprise or consist of a polymeric material. The plunger 1200 may comprise or consist of a homogeneous material.

[0088] The plunger 1200 may comprise a series of parts each having a different function, prominent feature, and / or different shape or dimension. The plunger 1200 may comprise one or more of a plunger connector portion 1203, a central portion 1204, a body portion 1206, and a sealing portion 1207. From the proximal end 1201 to the distal end 1202, the parts may be arranged in the order of the connector portion 1203, the central portion 1204, the body portion 1206, the sealing portion 1207, and the end portion 1210.

[0089] The plunger connector portion 1203 is configured to be connected to a liquid handling system, for example, by a snap fit connection. The plunger connector portion 1203 may be configured to be fully received within the pipette body connector portion 1103 of the pipette body 100. The plunger connector portion 1203 may include a split tubular wall 1220 that may be defined by a plurality of flexible segments 1221. The flexible segments 1221 are elastically deflected in the radially inward direction, from a first inner diameter where the flexible segments are not deflected and the plunger connector portion is in a stationary state, to a second inner diameter where the flexible segments are deflected radially inward and the plunger connector portion is in a pushed-in state, so as to reduce the inner diameter of the proximal end 1201 of the plunger 1200. In the depicted embodiment, the plunger connector portion 1203 includes three axially extending cuts or slots 1222 that demarcate the three flexible segments 1221 in the tubular wall 1220. The plunger connector portion 1203 may include any suitable number of axially extending cuts 1222 and may define any number of flexible segments 1221. The configuration of the flexible segments 1221 and slots 1222 allows the plunger connector portion to be pushed in without a large pushing force. The plunger connector portion 1203 may further include one or more radially extending mechanisms 1223 on its outer surface, whereby the plunger can be coupled to a pipette operating head. The radially extending mechanism on the outer surface of the plunger connector portion 1203 may include a radially outwardly extending protrusion and / or a radially inwardly extending recess or groove. The radially extending mechanism may extend circumferentially. In the depicted embodiment, the radially extending mechanism on the outer surface of the plunger connector portion 1203 includes a spherical head 1223 defined above an annular groove on the outer surface of the plunger connector portion 1203 at the upper end of the plunger. Preferably, the second inner diameter to which the plunger connector portion shrinks is smaller than the first inner diameter by at least the radial extent of the radially extending mechanism 1223, that is, by at least half of the difference between the outer diameter of the spherical head 1223 and the outer diameter of the narrowest part of the annular groove.

[0090] The plunger connector part 1203 may further include an inner wall 1224 extending laterally from the inner surface of the plunger connector part 1203. The inner wall 1224 may be positioned at the end of the flexible segment 1221. The inner wall 1224 may be positioned close to the main body part 1206. The inner wall 1224 forms a restricting part that crosses the hole of the plunger connector part. Thereby, a surface against which the head of the tightening rod can abut is provided, and the pipette is taken out. As shown in FIG. 17, the inner wall 1224 may extend across the entire width of the hole inside the plunger 1200. However, this is not necessarily the case. It is sufficient that the inner wall 1224 restricts the size of the hole to be less than the outer diameter of the head of the tightening rod.

[0091] The central portion 1204 may comprise an annular shoulder. The central portion 1204 may be substantially conical or dome-shaped. In the depicted embodiment, the central portion 1204 is a frustoconical shoulder extending in the radial direction. The central portion 1104 of the pipette body 1100 is preferably configured to receive, engage, and center the plunger 1200 in a straight line. In the embodiment shown in FIG. 14, the two central portions have corresponding geometric shapes. The body portion 1206 of the plunger 1200 may be configured to be received within the body portion 1106 of the pipette body 1100. The body portion 1206 may be substantially cylindrical and / or elongated. The body portion 1206 may have a substantially uniform diameter. The body portion 1206 may extend along at least half, optionally at least two-thirds, of the length of the plunger. The body portion 1206 may have a diameter larger than the diameter of the end portion 1210. The sealing portion 1207 of the plunger 1200 may be configured to be received within the bridging portion 1107 of the pipette body 1100. The sealing portion 1207 may be configured to form a seal against the inner wall of the pipette body 1100. The sealing portion 1207 may form a liquid-tight seal within the pipette body such that when the plunger 1200 is installed within the pipette body 1100, fluid does not flow from the proximal side of the sealing portion 1207 to the distal side of the sealing portion 1207. The sealing portion 1207 may be at least partially flexible. The sealing portion 1207 may be configured to bridge the body portion 1206 to the end portion 1210. The sealing portion 1207 may define a step between the body portion 1207 and the end portion 1210. The sealing portion 1207 may be substantially tapered, conical, and / or dome-shaped. The end portion 1210 of the plunger 1200 may be configured to be received within the end portion 1110 of the pipette body 1100. The end portion 1210 may have a diameter smaller than the sealing portion 1207 and / or the body portion 1206.

[0092] With reference to FIGS. 17-21, a method for connecting pipette 1010 to pipette operation head 100 of the present invention will be described below. Although the figures related to the following description show only a single pipette, it will be understood that one or more of the connection, aspiration, dispensing, and removal operations described can be applied simultaneously to multiple pipettes. For example, if the pipette operation head comprises 384 mounts, the following description may be applicable to the simultaneous connection of 384 pipettes, or any subset thereof.

[0093] In FIG. 17, both the pipette body clamping mechanism 130 and the plunger clamping mechanism 150 are in a released state. When the pipette body clamping mechanism 130 is in the released state, the pipette body clamping plate 125 is at its uppermost position relative to the lower surface of the pipette body mounting plate 121. Importantly, at this position, the clamping region of the pipette body clamp sleeve is axially offset from the annular groove around the outer surface of the pipette body mount sleeve. When the plunger clamping mechanism 150 is in the released state, as shown, the plunger clamping plate 145 is at its uppermost position, and the enlarged head 148 of the plunger clamping rod 147 is axially offset from the annular groove in each inner surface of the plunger mount sleeve. Subsequently, the entire pipette operation head 100 is axially moved towards a number of pipettes 1010 using a pipette head Z motor (not shown) such that the pipette body mount sleeve is received within the pipette body connector portion of the pipette body 1100. While the pipette body mount sleeve 123 is being inserted into the proximal end of the pipette body 1100, the annular rib 1123 of each pipette body 1100 rides up on the outer surface of the pipette body mount sleeve 123 and deflects the pipette body connector portion of each pipette body outward to the expanded position. Once the annular rib 1123 is received in the annular groove 124 as shown in FIG. 17, the flexible segment returns to an undeflected or only partially deflected state. At this position, the pipette body connector portion is in a stationary state, and each pipette body 1100 is coupled to its respective pipette body mount sleeve 123 by a snap-fit connection. This is step 1.

[0094] Step 2 will be described with reference to FIG. 18. In Step 2, as shown in FIG. 18, the pipette body clamping mechanism 130 is engaged by lowering the pipette body clamping plate 125 and moving it away from the pipette body mounting plate. As a result, the pipette body clamping sleeve 127 extends around the pipette body connector portion 1103 of each pipette body 1100, such that the clamping region of each pipette body clamping sleeve is adjacent to the snap-fit connection between each pipette body 1100 and its respective pipette body mounting sleeve 123. The inner diameter of the clamping region 128 is less than the expanded diameter of the pipette body connector portion 1103 and may, for example, be substantially the same as the unexpanded outer diameter or the "first" outer diameter of the pipette body connector portion. With this configuration, the pipette body connector portion 1103 cannot fully expand, thus preventing the radially extending mechanism 1123 on the inner surface of the pipette body 1100 from being released from the groove 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 the need to apply any large force to the pipette body connector portion of the pipette body 1100. This can reduce the force required to engage the pipette body clamping mechanism.

[0095] Between Step 1 and Step 2, the pipette body clamping mechanism may optionally be moved to a partially engaged "pre-lock" position between the released state and the engaged state, in which the tapered region 129B of each clamp sleeve 127 is adjacent to the recess 124 on the outer surface of its respective pipette body mounting sleeve 123. This can facilitate the picking of some of the multiple bodies from the box, as the picked body can be fixed relative to the pipette body mount without interference between the pipette body clamping plate and the multiple unpicked bodies. Once the picked body has been lifted by the pipette operating head above the multiple unpicked bodies, the picked body can subsequently be fully clamped in place by moving the pipette body clamping plate 125 to the clamping position.

[0096] Step 3 is described with reference to FIG. 19. In Step 3, the entire plunger attachment assembly 140 is lowered using a dispensing drive actuator. As a result, the plunger mount sleeve 143 contacts the plunger connector portion 1203 at the upper or proximal end of the plunger 1200. Further downward movement of the plunger attachment assembly 140 causes the inner surface of the plunger mount sleeve 143 to ride up on the outer surface of the plunger connector portion, deflecting the plunger connector portion inward to a contracted or pushed-in position, and the spherical head 1223 at the top of the plunger 1200 is received in the groove 144 on the inner surface of the plunger mount sleeve 143. Once the spherical head 1223 is received in the groove 144 on the inner surface of the plunger mount sleeve 143 as shown in FIG. 19, the flexible segment 1221 of the plunger connector portion 1203 returns to an undeflected or partially deflected state. In this position, the plunger connector portion is in a stationary state, and each plunger 1200 is coupled to its respective plunger mount sleeve 143 by a snap-fit connection.

[0097] Step 4 is described with reference to FIG. 20. In Step 4, the plunger clamping plate 145 is axially moved by the plunger clamping drive mechanism towards the plunger mounting plate 141 until the head 148 of the plunger clamping rod is adjacent to the snap-fit connection between the plunger and the plunger mounting sleeve. The outer diameter of the head 148 of each clamping rod is greater than the inner diameter of the plunger in the contracted state, or the "second inner diameter". For example, the outer diameter of the head 148 of each clamping rod may be substantially the same as the inner diameter of the non-deflected plunger, or the "first" inner diameter. With this configuration, the plunger connector portion cannot fully contract to the contracted position, and thus prevents 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 large pushing force to the plunger connector portion. This reduces the force required to engage the plunger clamping mechanism.

[0098] To perform the aspiration operation, the pipetting head 100 is moved to the desired position relative to the set of liquid samples using the pipetting head Z motor. The plunger of each pipette is then lifted within its respective pipette body using a direct drive actuator as shown in FIG. 21, moving the entire plunger mounting assembly 140 away from the pipette body attachment mechanism 120 to draw fluid into the pipette body. Subsequently, by using the dispensing drive actuator assembly to move the plunger clamping mechanism in the opposite direction, the fluid can be dispensed as desired.

[0099] Once the aspiration and dispensing operations are complete, the pipette or pipettes can be removed as follows. First, each plunger is moved to the lowermost position to which they travel inside their respective pipette bodies, and the pipette body clamping mechanism 130 moves the pipette body clamping plate 125 towards the pipette body mounting plate 121, and the clamp sleeve 127 is displaced from alignment with the snap-fit connection between each pipette body and its respective pipette body mount 123 and released by moving it away from the outer surface of the pipette body. Next, the plunger clamping plate 145 is moved towards the plunger mounting plate 141 beyond the engaged position, and the head 148 of each clamping rod 147 is displaced from alignment with the snap-fit connection between each plunger 1200 and its respective plunger mount 143 and instead aligned the neck portion 149A of each clamping rod 147 with the snap-fit connection and caused the distal end face of the head of the clamping rod to abut against the inner wall 1224 of the plunger connector portion 1203. Since the neck portion 149A of the clamping rod 147 has an outer diameter less than the second pushed-in inner diameter of the plunger connector portion 1203, when the clamping rod is in this position, the plunger connector portion is not restricted from deflecting inwardly into the pushed-in state. Thus, by the continued downward movement of the plunger clamping plate 145, the spherical head 1223 of the plunger connector portion 1203 is released from the corresponding radially extending mechanism 144 of the plunger mount 143, and the plunger 1200 is removed from the pipette operating head. Further downward movement of the plunger clamping plate, and thus the clamping rod and the plunger itself, causes the distal end of the plunger to be pressed against the respective parts of the pipette body within which they are located. In this way, the plunger and plunger clamping mechanism can be used to release the pipette body 1100 from the pipette body mount 123, whereby the pipette 1010 is removed from the pipette operating head.

[0100] The present invention has been described above with reference to one or more preferred embodiments, but it will be understood that various changes or modifications can be made without departing from the scope of the invention as defined in the appended claims.

[0101] The present invention may be described or defined according to the following sections.

[0102] 1. A pipette operating head for a liquid dispensing device for use with a plurality of pipettes, each of the plurality of pipettes having a pipette body and a plunger provided within the pipette body, the pipette operating head comprising a pipette operating head chassis, a pipette body attachment assembly for holding the pipette body, a plunger attachment assembly for holding the plunger, a dispensing drive actuator assembly operable to move the plunger attachment assembly relative to the pipette body attachment assembly along a drive shaft 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 mechanism coupling the dispensing drive motor to the plunger attachment assembly to cause its axial displacement, a pipette body clamping mechanism operable to selectively clamp the pipette bodies of the plurality of pipettes to the pipette body attachment assembly, a pipette body clamping plate positioned below the plunger attachment assembly, a plurality of pipette body clamping members on the pipette body clamping plate, A pipette body clamp drive mechanism operable to selectively engage a pipette body tightening mechanism, having a linear actuator and a pipette body clamp drive link mechanism, wherein the pipette body clamp drive link mechanism couples the linear actuator to a pipette body tightening plate, the pipette body clamp drive link mechanism is fixed relative to the pipette body tightening plate and includes at least one standoff extending axially between the pipette body tightening plate and the linear actuator, and the linear actuator is configured to move axially relative to a pipette operation head chassis by at least one standoff to selectively engage the pipette body tightening mechanism, the pipette body clamp drive mechanism A pipette body tightening mechanism comprising An operation head comprising

[0103] 2. The pipette operation head according to paragraph 1, wherein the at least one standoff comprises a plurality of standoffs, each of the plurality of standoffs being connected to an outer edge of the pipette body tightening plate.

[0104] 3. The pipette operation head according to paragraph 1 or 2, wherein the at least one standoff comprises at least one guide rod, and along the at least one guide rod, the plunger mounting assembly is slidably supported when axially displaced by a dispensing drive actuator assembly.

[0105] 4. The pipette operation head according to any one of paragraphs 1 to 3, wherein the at least one standoff is slidably supported by a pipette operation head chassis.

[0106] 5. The pipette operation head according to any one of paragraphs 1 to 4, wherein the linear actuator is located above the plunger mounting assembly.

[0107] 6. 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 the axial movement of at least one stand-off, the pipette operation head according to any one of paragraphs 1 to 5.

[0108] 7. The screw mechanism is hollow and defines an axial hole through which the dispensing drive mechanism extends, the pipette operation head according to paragraph 6.

[0109] 8. The dispensing drive mechanism and the screw mechanism are concentric, the pipette operation head according to paragraph 7.

[0110] 9. The screw mechanism comprises a first concentric sleeve and a second sleeve coupled by a screw connection, the pipette body clamping motor being configured to rotate the first sleeve around the second sleeve to cause the axial movement of at least one stand-off, the pipette operation head according to paragraph 7 or paragraph 8.

[0111] 10. The pitch circle diameter of the screw connection is less than 30 percent of the width of the pipette body clamping plate, the pipette operation head according to paragraph 9.

[0112] 11. The pipette body clamping motor is coupled to the screw mechanism by one or more gears, the pipette operation head according to any one of paragraphs 6 to 10.

[0113] 12. The pipette body clamping motor is fixed to the pipette operation head chassis, the pipette operation head according to any one of paragraphs 6 to 11.

[0114] 13. A plunger clamping mechanism operable to clamp the plungers of a number of pipettes to a plunger attachment assembly, a plunger clamping plate, a plurality of plunger clamping members on the plunger clamping plate, A plunger clamp drive mechanism operable to selectively engage a plunger tightening mechanism and comprising a linear actuator configured to cause relative axial movement between a plunger tightening plate and a plunger mounting assembly and to selectively engage the plunger tightening mechanism The pipetting operation head according to any one of paragraphs 1 to 12, further comprising a plunger tightening mechanism having

[0115] 14. The linear actuator of the plunger clamp drive mechanism comprises a plunger clamp motor and a screw mechanism for converting the rotational movement of the plunger clamp motor into the axial movement of the plunger tightening plate. The pipetting operation head according to paragraph 13

[0116] 15. The screw mechanism of the plunger clamp drive mechanism comprises concentric first and second sleeves coupled by a screw connection, the second sleeve being fixed relative to the plunger mounting assembly, and the plunger clamp motor being configured to rotate the first sleeve around the second sleeve to cause axial movement of the plunger tightening plate. The pipetting operation head according to paragraph 14

[0117] 16. The pitch circle diameter of the screw connection is less than 30 percent of the width of the plunger tightening plate. The pipetting operation head according to paragraph 15

[0118] 17. The screw mechanism of the plunger clamp drive mechanism is hollow and defines an axial hole for receiving a part of the dispensing drive mechanism. The pipetting operation head according to any one of paragraphs 14 to 16

[0119] 18. The dispensing drive mechanism comprises a ball screw actuator nut at least partially received within the axial hole of the screw mechanism of the plunger clamp drive mechanism. The pipetting operation head according to paragraph 17

[0120] 19. The dispensing drive mechanism and the screw mechanism of the plunger clamp drive mechanism are concentric, and the pipetting operation head according to paragraph 17 or 18.

[0121] 20. The plunger attachment assembly includes a plurality of plunger mounts, and the plurality of plunger clamping members are each coaxial with one of the plurality of plunger mounts and include a plurality of clamping rods extending within the plunger mount, and when the plunger clamping mechanism is engaged, it restricts the inward movement of the plunger received within the plunger mount, and the pipetting operation head according to any one of paragraphs 13 to 19.

[0122] 21. The plunger attachment assembly further includes a plunger attachment plate, and a plurality of plunger mounts are provided on the plunger attachment plate, and the pipetting operation head according to paragraph 20.

[0123] 22. A main body having a deck for receiving one or more microplates, A pipetting operation head according to any one of paragraphs 1 to 21, and the pipetting operation head positioned on the deck And a liquid dispensing device comprising.

[0124] 23. A pipetting operation head for a liquid dispensing device for use with a plurality of pipettes, each of the plurality of pipettes having a pipette body and a plunger provided within the pipette body, and the pipetting operation head includes A pipetting operation head chassis, A pipette body attachment assembly for holding the pipette body, A plunger attachment assembly for holding the plunger, A dispensing drive actuator assembly operable to move a plunger attachment assembly relative to a pipette body attachment assembly along a drive shaft to perform a dispensing or aspiration operation, the dispensing drive actuator assembly comprising a dispensing drive motor and a dispensing drive mechanism, wherein the dispensing drive mechanism couples the dispensing drive motor to the plunger attachment assembly to cause axial displacement thereof. A plunger clamping mechanism operable to clamp the plungers of a plurality of pipettes to the plunger attachment assembly, a plunger clamping plate, a plurality of plunger clamping members on the plunger clamping plate, and a plunger clamp drive mechanism operable to selectively engage the plunger clamping mechanism. The plunger clamping mechanism includes a linear actuator configured to cause relative axial movement between the plunger clamping plate and the plunger attachment assembly and to selectively engage the plunger clamping mechanism. The pipette operating head having the plunger clamping mechanism. An operating head comprising

[0125] 24. The linear actuator of the plunger clamp drive mechanism of the pipette operating head according to paragraph 23, comprising a plunger clamp motor and a screw mechanism for converting the rotational movement of the plunger clamp motor into the axial movement of the plunger clamping plate.

[0126] 25. The screw mechanism of the plunger clamp drive mechanism of the pipette operating head according to paragraph 24, comprising concentric first and second sleeves coupled by a screw connection, the second sleeve being fixed relative to the plunger attachment assembly, the plunger clamp motor being configured to rotate the first sleeve around the second sleeve to cause axial movement of the plunger clamping plate.

[0127] 26. The pitch circle diameter of the screw connection is less than 30 percent of the width of the plunger clamping plate, the pipetting operation head according to paragraph 25.

[0128] 27. The screw mechanism of the plunger clamp drive mechanism is hollow and defines an axial hole for receiving a part of the dispensing drive mechanism, the pipetting operation head according to any one of paragraphs 24 to 26.

[0129] 28. The dispensing drive mechanism includes a ball screw actuator nut that is at least partially received within the axial hole of the screw mechanism of the plunger clamp drive mechanism, the pipetting operation head according to paragraph 27.

[0130] 29. The dispensing drive mechanism and the screw mechanism of the plunger clamp drive mechanism are concentric, the pipetting operation head according to paragraph 27 or paragraph 28.

[0131] 30. The plunger attachment assembly includes a plurality of plunger mounts, and the plurality of plunger clamping members are each coaxial with one of the plurality of plunger mounts and include a plurality of clamping rods extending within the plunger mount, restricting the inward movement of the plunger received within the plunger mount when the plunger clamping mechanism is engaged, the pipetting operation head according to any one of paragraphs 23 to 29.

[0132] 31. The plunger attachment assembly further includes a plunger attachment plate, and a plurality of plunger mounts are provided on the plunger attachment plate, the pipetting operation head according to paragraph 30.

Claims

1. A pipette operating head for a liquid dispensing apparatus for use with a plurality of removable pipettes, wherein each of the plurality of removable pipettes has a pipette body and a plunger provided within the pipette body, and the pipette operating head is Pipette operating head chassis and A pipette body mounting assembly for holding the pipette bodies of the numerous removable pipettes, A plunger mounting assembly for holding the plungers of the numerous removable pipettes, A dispensing drive actuator assembly capable of moving the plunger mounting assembly along a drive shaft relative to the pipette body mounting assembly to perform a dispensing or aspiration operation, comprising a dispensing drive motor and a dispensing drive mechanism, wherein the dispensing drive mechanism connects the dispensing drive motor to the plunger mounting assembly, causing its axial displacement, The pipette body mounting assembly includes a pipette body tightening mechanism that can be operated to selectively tighten the pipette bodies of the numerous pipettes, A pipette body clamping plate positioned below the plunger mounting assembly, Multiple pipette body clamping members on the pipette body clamping plate, A pipette body clamp drive mechanism operable to selectively engage the pipette body clamping mechanism, comprising a linear actuator and a pipette body clamp drive link mechanism, wherein the linear actuator is coupled to the pipette body clamping plate by the pipette body clamp drive link mechanism, the pipette body clamp drive link mechanism comprising at least one standoff fixed to the pipette body clamping plate and extending axially between the pipette body clamping plate and the linear actuator, the linear actuator is configured to move the at least one standoff axially relative to the pipette operating head chassis to selectively engage the pipette body clamping mechanism, A pipette body tightening mechanism equipped with A pipette operating head equipped with a pipette.

2. The pipette operating head according to claim 1, wherein the at least one standoff comprises a plurality of standoffs, each of which is connected to the outer edge of the pipette body clamping plate.

3. The pipette operating head according to claim 1, wherein the at least one standoff comprises at least one guide rod, and the plunger mounting assembly is slidably supported along the at least one guide rod when it is axially displaced by the dispensing drive actuator assembly.

4. The pipette operating head according to any one of claims 1 to 3, wherein at least one standoff is slidably supported by the pipette operating head chassis.

5. The pipette operating head according to any one of claims 1 to 3, wherein the linear actuator is located on the plunger mounting assembly.

6. The pipette operating head according to any one of claims 1 to 3, wherein the linear actuator comprises a pipette body clamp motor and a screw mechanism for converting the rotational motion of the pipette body clamp motor into the axial motion of the at least one standoff.

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

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

9. The pipette operating head according to claim 7, wherein the screw mechanism comprises a concentric first sleeve and a second sleeve connected by a screw link, and the pipette body clamp motor is configured to rotate the first sleeve around the second sleeve, thereby causing axial motion of the at least one standoff.

10. The pipette operating head according to claim 9, wherein the pitch circle diameter of the screw connection is less than 30 percent of the width of the pipette body clamping plate.

11. The pipette operating head according to claim 6, wherein the pipette body clamp motor is coupled to the screw mechanism by one or more gears.

12. The pipette operating head according to claim 6, wherein the pipette body clamp motor is fixed to the pipette operating head chassis.

13. The plunger mounting assembly includes a plunger tightening mechanism that can be operated to tighten the plungers of the numerous pipettes, Plunger clamping plate and Multiple plunger clamping members on the plunger clamping plate, A plunger clamp drive mechanism that can be operated to selectively engage the plunger tightening mechanism, Equipped with, A linear actuator configured to cause relative axial movement between the plunger clamping plate and the plunger mounting assembly, thereby selectively engaging the plunger clamping mechanism. A pipette operating head according to any one of claims 1 to 3, further comprising a plunger tightening mechanism having

14. The pipette operating head according to claim 13, wherein the linear actuator of the plunger clamp drive mechanism comprises a plunger clamp motor and a screw mechanism for converting the rotational motion of the plunger clamp motor into axial motion of the plunger clamping plate.

15. The pipette operating head according to claim 14, wherein the screw mechanism of the plunger clamp drive mechanism comprises a concentric first sleeve and a second sleeve connected by a screw link, the second sleeve being fixed to the plunger mounting assembly, and the plunger clamp motor is configured to rotate the first sleeve around the second sleeve, thereby causing axial movement of the plunger clamping plate.

16. The pipette operating head according to claim 15, wherein the pitch circle diameter of the screw connection is less than 30 percent of the width of the plunger clamping plate.

17. The pipette operating head according to claim 14, wherein the screw mechanism of the plunger clamp drive mechanism is hollow and defines an axial hole for receiving a part of the dispensing drive mechanism.

18. The pipette operating head according to claim 17, wherein the dispensing drive mechanism comprises a ball screw actuator nut that is at least partially housed in the axial hole of the screw mechanism of the plunger clamp drive mechanism.

19. The pipette operating head according to claim 17, wherein the dispensing drive mechanism and the screw mechanism of the plunger clamp drive mechanism are concentric.

20. The pipette operating head according to claim 13, wherein the plunger mounting assembly comprises a plurality of plunger mounts, each of which a plurality of plunger clamping members is coaxial with one of the plurality of plunger mounts and comprises a plurality of clamping rods extending within the plunger mount, and when the plunger clamping mechanism is engaged, it restricts the inward movement of a plunger received within the plunger mount.

21. The pipette operating head according to claim 20, wherein the plunger mounting assembly further comprises a plunger mounting plate, and the plurality of plunger mounts are provided on the plunger mounting plate.

22. A main body equipped with a deck for receiving one or more microplates, A pipette operating head according to any one of claims 1 to 3, wherein the pipette operating head is positioned on the deck and A liquid dispensing device equipped with the following features.

Images