DEVICE FOR MOVING PROBES

A device and a method for moving probes like aspiration probes in automated analyser systems and provides a device for aspirating samples or reagents, comprising a lift chassis, a motor for driving a rotatable spindle nut, wherein the motor is attached to the lift chassis, an aspiration probe which has on its outer side a lead screw which is running through the spindle nut of the motor.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present invention claims priority to national Luxembourg patent application no. LU102498 filed on Feb. 3, 2021. The afore mentioned application is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The invention relates to a device and a method for moving probes like aspiration probes in automated analyser systems.

Brief Description of the Related Art

Automated analyzer systems for use in clinical diagnostics and life sciences are produced by a number of companies. For example, STRATEC® SE, Birkenfeld, Germany, produces a number of devices for specimen handling and detection for use in automated analyzer systems and other laboratory instrumentation.

STRATEC designs and manufactures diagnostic instruments for performing diagnostic assays. The processing of diagnostic assays in automated analyzer systems often requires the repeated dispense of samples or reagents into specific reaction vessels (of so-called consumables) and the subsequent aspiration from the respective cavities. In most cases the aspiration is required to remove already used or not required liquid volumes from the vessels to allow further processing (e.g., add of next reagent). Therefore, it is necessary to differentiate between the aspiration of supernatants or volume proportions and the aspiration of whole liquid volumes. For example, multiple wash steps with different wash buffers will be performed in clinical or molecular analyzers in order to eliminate contaminants and thus to decrease background signals in the sample

A device is known from the prior art which provides one aspiration probe per lift. Each probe is mounted on a cantilever arm which is connected to a trapezoidal gear rack. A stepper motor with pinion drives the rack. Two mounted half shells and two slide bearings allow the linear guiding of the gear rack and provides also interfaces for the attachment of the motor, an initialization sensor (light barrier) as well as the mounting of the complete lift. The axial or linear tolerance compensation is an integral part of the aspiration probe. Coil springs allow to touch the consumable bottoms independently of mechanical tolerances in an axial or linear movement direction. The concept of the lift requires an additional bushing for the linear guiding of the probe.

The wash or aspiration lift of said device is based on the same linear drive mechanism which is described above. The main difference is the fact that multiple aspiration probes are moved simultaneously by a common adapter plate onto which they are mounted. Two gear racks are driven by one motor which is connected via a synchronization shaft with the relating pinions. The integrated PCBA (=printed circuit board assembly) provides sensor devices for aspiration monitoring.

The washing module includes a lift mechanism with also multiple aspiration positions. Five probes are mounted to a carrier or sledge that is axially moved by a lead screw or spindle drive. A probe guide above the multi-cavity consumable ensures the directed linear stroke of the aspiration probes. The system performs other washing functionalities as well and provides its own control electronics.

Another device which is known in the art also contains its own electronics responsible for motion control and aspiration monitoring, among other functions. Each device is equipable with two probes. These probes (with integrated compression springs for tolerance compensation) are hooked to a sledge that is guided in linear direction by the lift backbone. A gear wheel segment with eccentric driver translates the rotary motion into a linear Z-movement of sledge and probe. Guide bushings in the lift base plate direct the probe motion. The gear wheel is rotated by a pinion which is directly mounted on a shaft of a stepper motor.

Another device that is known from the prior art is also multi-position washer. The aspiration probe lift concept is similar to the former described devices. A main difference in comparison to other devices is that beside the aspiration probe also the reagent dispense ports are moved in Z-direction. All modules provide different sensor systems in order to ensure the reagent independent monitoring of the aspiration process:Optical sensors: Monitoring the liquid aspiration through the transparent probeUltrasonic sensors: Monitoring the liquid aspiration through tubing

Further, a device is known where the probes for aspiration and dispense are combined in an assembly. The angled dispense probe is aligned to the aspiration probe to clean or rinse the outer surface via the liquid injection. For tolerance compensation the probe assembly is hooked to flat spring. A gear rack drive performs the linear lift movement.

A dispense application that is already known has a hollow spindle and comprises a liquid handling device for the aspiration and dispense of liquids similar to a pipettor. The automated pipetting system consists of a pipette lift and a positive displacement pump. Both submodules are based on a linear stepper motor. The coaxially moved hollow spindle of the lift is equipped with a pipette at the tip or front edge which is facing the liquid reservoir. The moving axis allows to dip the pipette into the liquid and vice versa. The rear end of the lift spindle is connected via a tubing with the air displacement pump to implement liquid aspiration and dispense steps. This solution is only intended for dispense applications and does not allow for the aspirates of liquid waste.

Published U.S. Patent Application US 2005/074363 A 1 discloses an automated apparatus for extracting liquid samples, particularly biological fluids such as urine, blood serum, plasma, cerebrospinal fluid and the like, from a container. In particular, the document provides a method to automatically extract a desired amount of sample fluid from a closed container in preparation for clinical diagnosis. The document is further related to a method and apparatus for cleaning liquid aspiration probes.

Published U.S. Patent Application US 2012/186367 A1 relates to pipetting device comprising more than one pipetting unit, wherein said pipetting units are independently movable in Y and Z direction and comprise at least one module arranged in a staggered manner compared to the adjacent pipetting unit.

Published Chinese Patent Application No. 111 735 981 A describes a mechanical arm sample injection module. The mechanical arm sample injection module comprises a first sampling device provided with a sampling needle assembly and a second sampling device provided with a pipette tip assembly, the first sampling device is used for sucking a reaction reagent into the reaction cup; the second sampling device is used for sucking a sample into the reaction cup; the mechanical arm sample injection module further comprises a transverse movement assembly, a longitudinal movement assembly and an up-down movement assembly. The transverse movement assembly drives the first sampling device and the second sampling device to move transversely, the longitudinal movement assembly drives the first sampling device and the second sampling device to move longitudinally, and the up-down movement assembly drives the first sampling device and the second sampling device to move up and down. The mechanical arm sample injection module can enable the first sampling device and the second sampling device to transversely move, vertically move and longitudinally move, namely move in three directions to flexibly control sampling, so a reaction reagent and a sample are added into a specified reaction cup, and accurate and rapid sampling is realized.

Published European Patent Application No. EP 1 075 869 A1 discloses a present micro array manufacturing apparatus including a substrate placement portion on which a plurality of substrates can be arranged, a titer plate for storing a solution including a living body sample, a solution storing member for taking in the solution from the titer plate and storing the solution therein, and a needle which can be inserted into the solution storing member to allow the solution stored in the solution storing member to adhere onto each of the substrates by a given quantity, wherein the solution storing member and needle are moved in directions where they approach and part away from the substrates to thereby form spots on the substrates. And, the individual operations of the solution storing member and needle are carried out by single drive means.

Published European Patent Application No. EP 2 754 498 A1 teaches an apparatus for aspirating liquid from a container, e.g., a test tube, having a puncturable stopper includes a pair of stepper motors that share a common linear actuator or drive member. One motor operates to axially advance the linear drive member (preferably a lead screw) to a position in which it serves to position a rigidly connected tube-detector/stripper member in engagement with the top of a stopper on a tube. Thereafter, the second motor operates to move along the surface of the same drive member to advance an aspiration probe through the engaged stopper and into a liquid aspirating position within the tube. Preferably, a linear guide rail, slidably mounted on a frame that supports the liquid-aspirating apparatus, serves to guide both the movement of the aspiration probe and the linear drive member. As a result of the shared components, the apparatus is highly precise and reliable

Disadvantages of the available solutions refer to a high effort and complexity for guiding and bearing of the aspiration probe and/or the actuated mechanism which generates the linear movement of the probe. Further, drive systems with high complexity and large number of parts for the realization of the linear or axial movement are used in known solutions. Existing devices use additional transmissions or gearing mechanisms to realize the linear probe movement.

Already available devices have the following disadvantages if the aspiration probe shall be able to reach the bottom of a liquid holding cavity. They require separate features or mechanisms for axial or linear tolerance compensation in movement direction. They need force or travel/stroke control with costly components for force and positioning monitoring. High wear and abrasions is necessary due to the high number of moved components which cause a reduced module and instrument reliability. Finally, a high effort for assembling and adjustment of lift components or the complete module (e.g. adhesive bonding/gluing of components plus alignment in a tool/fixture) will be necessary.

SUMMARY OF THE INVENTION

It is therefore the object of this invention to provide a device and a method for aspirating samples or reagents requiring less space by a compact form.

The present invention provides a device for aspirating samples or reagents, comprising a lift chassis, a motor for driving a rotatable spindle nut, wherein the motor is attached to the lift chassis, an aspiration probe which has on its outer side a lead screw which is running through the spindle nut of the motor.

In a further aspect of the device, it is intended that a distribution board is attached to the lift chassis, for controlling the motor.

The device according to the invention may further comprise an aspiration probe that is vertically orientated.

In a further embodiment of the invention, the spindle nut is accommodated in a rotor with plain bearing or linear ball bearings which are surrounded by a stator.

It is also envisaged that a rear motor cap is located on the upper side of the motor and a front motor cap is located on the underside of the motor.

The device according to the invention may further comprise a wave compression spring that is arranged between the upper ball bearing and the rear motor cap.

In a further aspect regarding the device of the present invention, a spindle nut, ball bearings, stator, rear motor cap and front motor cap and wave compression spring are accommodated in a motor housing.

A further embodiment may have an aspiration probe that comprises an aspiration needle that is at least partially enclosed by a lead screw which is connected to an aspiration probe head.

A device according to the invention may further comprise a lead screw and aspiration probe head that are one part.

It is further intended that the aspiration probe head comprises a hose connection and one side a probe flag with a key-like cross section.

The device according to the invention may further comprise an upper end of a tubing of the aspiration probe is the hose connection.

It is also envisaged in a further aspect of the invention the aspiration probe head comprised cut-outs as indicator windows through which the transparent inner tubing of the aspiration probe is visible.

The device according to the invention may comprise in another embodiment the lower end of the aspiration probe being slotted.

The device as described above may further comprise an upper part of the chassis that comprises a linear guiding with a cross section for accommodating the key-like cross section of the probe flag of the aspiration probe head having a corresponding cross-section.

In another aspect of the invention, the distribution board may comprise at least one initialization sensor which surrounds at on two sides the aspiration probe, an aspiration monitoring sensor surrounding the aspiration probe at least on two sides, a lift connector for connecting the device to control member of a connected device, a motor connector for connecting the distribution board to the motor and an additional connector for further external devices. The initialization sensor can be a light barrier for detecting the probe flag of the aspiration probe head.

It is also intended in a further aspect of the invention that the upper part of the lift chassis comprises a hose locking adapter which comprises a cylindrical part for accommodating the aspiration hose and on one end a cantilever for fixation of the locking adapter in the lift chassis.

The lift chassis may comprise at least one of selected from the group consisting of a motor interface for fixation of the motor on its underside, sides recesses on its lateral sides for fixation of aspiration hoses, a vertical orientated linear guiding for the aspiration probe and a hole for taking up the hose locking adapter.

The invention refers further to an embodiment comprising a dispense manifold that is mounted to the underside of the motor, wherein the dispense manifold comprises a baseplate comprising a switching valve connected to a liquid supply, an injector nozzle connected to the switching valve, wherein the injector nozzle's outlet is directed towards the lower end of the aspiration probe.

Still other aspects, features, and advantages of the present invention are readily apparent from the following detailed description, simply by illustrating preferable embodiments and implementations. The present invention is also capable of other and different embodiments and its several details can be modified in various obvious respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive. Additional objects and advantages of the invention will be set forth in part in the description which follows and in part will be obvious from the description or may be learned by practice of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The technical problem is solved by the independent claims. The dependent claims cover further specific embodiments of the invention.

The invention relates to a lift assembly for the axial or linear movement of an aspiration probe. In association with a fluid pump, the lift module provides the possibility to aspirate liquids from different kinds of reaction vessels or other liquid holding cavities. According to the scope of the invention the following description will be focusing the lift module.

A particular feature is the lead screw motor with the integrated aspiration probe which drives through anon-captive linear actuator and lead screw motor, respectively. The “on-board” distributor electronics allows for the control of the lift assembly and also the process monitoring of the aspiration process via an external control unit.

The single probe aspiration lift1is shown inFIGS. 1A-1Din different perspective views, and it basically consists of a lead screw motor (or stepper motor)2, a lift chassis5with distribution/sensor board40and an aspiration probe9which is surrounded by a lead screw11. The main function of the device is the axial or linear movement of the mentioned aspiration probe to perform workflow required aspiration steps. The lead screw drive (motor and lead screw) translates the rotary motion of the motor and a spindle nut which is arranged within the rotor into the desired stroke movement.

It is to be noted that there is no prior art know which provides an aspiration probe that is surrounded by a lead screw so that the probe has a double function, aspirating or dispensing fluids and being directly moved through a lead screw motor. Published U.S. Patent Application US 2005/074363 A1 provides a lead screw which is separated from the aspiration probe. The technical difference to the present invention is that the lead screw is stationary, and the actuator moves. The present invention provides a lead screw that moves and thus the aspiration probe moves too because aspiration probe and lead screw are a single piece.

The device needs to be operated in conjunction with a fluid pump or pump system in order to allow the aspiration functionality. Each aspiration probe is connected to a separate pump (or pump channel) via hoses10. The device lifts the aspiration probe into different liquid containing cavities and the connected pump transfers the media to another cavity which can be an intermediate or storage reservoir. Movement of the lift as well as analyzing sensor signals of sensors which are placed at the distribution board has to be controlled by separate control electronics, which also provides power and communication interfaces. Alternatively, this control electronic could also be implemented in the device.

One core element of the module is the non-captive lead screw motor with hollow shaft13and integrated axial tolerance compensation mechanism (FIG. 2). The motor provides a wave compression spring15which is located between a rear motor cap (part of the stator housing) and rotor19.FIG. 2shows further a front rotor cap18, the stator21and ball bearings of the motor via a cross-sectional view.

FIGS. 3A-3Bshow that the wave compression spring15allows an axial movement indicated by the arrow of the lead screw11, respectively rotor shaft, inside the motor when the tip of the aspiration probe reaches/touches an end surface or mechanical stop (not shown). This mechanism ensures an error free (e.g., no step loss of stepper motor) and reliable positioning of the aspiration probe independent of potential hardware and consumable tolerances of the peripheral and interacting components. Thereby a complete aspiration of liquid holding cavities is possible because the probe is able to reach the bottom surface.

FIG. 4shows the aspiration probe9with integrated lead screw11geometry, aspiration probe tip12and aspiration probe head14. The aspiration probe9may be made of steel which is coaxially arranged into the lead screw thread/geometry and accordingly moves along the motor rotation axis. Due to the configuration of the aspiration probe with an at least partially surrounding lead screw, the setup is deemed to be one piece due to the permanent connection of the lead screw around the aspiration probe.

FIGS. 5A-5Cshow an aspiration probe head14in detail. Manual handling (e.g., for maintenance exchange) by technician or service personnel is supported by the recessed grips16and enables a two-finger operation. The flag-like feature20is used for linear guiding (plain bearing but can also be a linear ball bearing) and functions as a rotation lock. The flag20cross section is shaped similar to the bit of a key and fits to a guide rail element25of the lift chassis. It limits the rotational tolerance of the aspiration probe and avoids unintended leave and/or removal of the aspiration probe in combination with the locking feature depicted inFIGS. 10A-10B.

FIGS. 5A-5Cshow that the protruding upper end of the probe is the connection port for the mounting of flexible aspiration hoses10(not shown). It is surrounded by the aspiration probe head14and represents the complete hose interface. All upper aspiration probe ends are chamfered28to facilitate hose assembly. The indicator window27(FIGS. 6A-6C) gives information about a correctly mounted aspiration hose10(pushed to end position). Kinking of the hose during movement of the aspiration probe (which can influence the aspiration process) will be avoided by a protective collar30. It also prevents a too tight routing of the hoses which also could affect hose kinking. A slot32at the aspiration probe tip12guarantees an aspiration without the generation of a vacuum and the consequential interruption or stop of the process when the probe is reaching the bottom of a cavity.

The embedded electronics on the printed circuit board arrangement (PCBA)40fromFIGS. 7A-7Care responsible for the power and signal distribution and provides sensors for detection purposes as well as process monitoring. The PCBA40ofFIGS. 7A-7Cshows an initialization sensor42, an aspiration monitoring sensor44, a lift connector46to superior electronics (CU PCBA) which is required to supply and control the SIPAL sub-module via the lift PCBA. The PCBA40ofFIGS. 7A-7Cfurther shows an additional connector48and a motor connector49.

The lead screw motor is directly connected to the PCBA. It also provides an additional interface for the connection of other actuators (e.g., switching valve).

The first on-board sensor (FIGS. 8A-8B) is an initialization sensor42, e.g., a light barrier, and allows the initialization of the lift mechanics. Trigger of the sensor is the already described flag-like element20of the aspiration probe9.

An optoelectronic sensor device which consists of a transmitter52(LED) and a receiver54is used to observe the fluid aspiration in the transparent hose10(FIG. 9) in a hose locking adapter51. The transmitter52sends infrared light through the transparent aspiration hose10to the receiver54. By the signal change and variation as well as the related interpretation/analysis it is possible to monitor the liquid handling process. It ensures that the aspiration was completed successfully, and processing can continue as planned/scheduled.

In the area of the aspiration monitoring sensor each hose will be fixated by a specific locking device, a hose locking adapter51, to avoid the disturbance or fluctuation of the measurement (FIGS. 10A-10B). InFIG. 10A, the hose locking adapter51is in an open/unlocked position, where the aspiration hose10can be inserted. After insertion of the hose10, the hose locking adapter51can be clamped by turning the cantilever55in a closed/locked position, which is shown inFIG. 10B.

In the closed state of the locking adapter51it is not possible to remove the aspiration probe9from the lift. The cantilever55functions also as mechanical hard stop and avoids that the lead screw11of the aspiration probe9losses the contact to the lead screw/spindle nut of the motor.

FIGS. 11A-11Bshow the hose locking adapter51in more detail and a side view of it in a closed/locked position. The hose locking adapter51can be actuated by the latch/cantilever55at the front. Fixation rips57at the inner side of the hose locking adapter51avoid an axial movement of the hose after locking. A snap interface59keeps the cantilever55of the hose locking adapter51closed after rotation.

The lift chassis5as shown inFIGS. 12A-12Cis the interface between motor, aspiration probe and electronics board. Primary function of the lift chassis5is the linear guiding of the aspiration probe9. For this purpose, it provides an integrated guide rail element25and interacts with the flag20(not visible) of the aspiration probe head14. The PCBA40will be mounted the lift chassis5. Integrated static hose clamp/fixation features60allow the reliable and repeatable routing of the tubing and should prevent kinking. A cover62at the rear side protects the PCB against environmental influences and conditions. The hose locking adapter51of the aspiration monitoring device will also be installed to the chassis in a hose adapter interface65. The lift chassis5further comprises a motor interface67with several holes for fixation of the lead screw motor2.

Depending on the installation conditions and the lift periphery each lift chassis5can be arranged and fixed in defined rotation angles on the motor2to address different integration requirements. This option is given by the different motor interfaces which are shown inFIGS. 12A-12C.

FIGS. 13A-13Bshow that the aspiration probe lift1can be combined with a dispense manifold100in order to perform washing functions including liquid dispense at a dedicated position. The dispense manifold100provides an integrated injection nozzle102fixed to the manifold body101which is facing the reaction vessel (not shown). For cleaning purposes, the injector nozzle102can be aligned to the aspiration probe9. According to this the reagent dispense is used to rinse the outer surface of the aspiration probe9. Each dispense manifold100will be equipped with a switching valve104for dispense control. The supply/pressure-side hose is connected to the liquid port105of the dispense manifold100.

The core of the invention is the small form factor of the lift assembly and the high degree of functional integration which leads to a low complexity stand-alone sub-module.Lead screw/spindle with integrated aspiration probe, tubing connection port, guiding features, handling interface for service personnel and light barrier flagLinear actuator (non-captive lead screw motor) with integrated mechanism for axial tolerance compensation to ensure reliable reaching of the reaction vessel bottom with the aspiration probeDistribution board (PCBA) including sensors for lift initialization and aspiration monitoring which needs be controlled by a separate control electronics.Lockable hose fixation device for reliable and repeatable positioning of aspiration tubing with respect to the aspiration sensorLift housing/chassis with linear guiding, lead screw rotation lock, hose routing features and distribution board interface.

The advantages of the invention can be summarized as follows:General motor with integrated axial tolerance compensation deviceLead screw with integrated aspiration probe/needleIntegrated aspiration monitoring deviceSmall footprint and compact form factor of lift assembly which facilitates integrationHigh degree of functional integrationLow module complexity due to low number of componentsLow tolerance chain and low influence of tolerances at performanceLess effort for guiding and bearing of movable componentsScalable design (e.g., lift/probe travel, probe diameter, motor size/torque etc.)Different precision classes feasible depending on the application requirementsOne central interface for electronic connection of moduleEasy removal and exchange of aspiration probe and/or tubing (serviceability)Module assembly without alignment/adjustment steps

Alternative approaches may encompassSIPAL comprises pump, tooSIPAL comprises control electronics, tooProviding dispense functionality in addition to aspirationLead screw/spindle with interface/mechanism for pick-up and/or eject of Disposable tips instead of steel probe

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