Pipette tips and rack systems for liquid processing equipment

Abstract

The pipette tip rack system features disposable refill packs and a reusable base. After use, the disposable refill packs are disassembled, and before disposal or recycling, the components can be stacked or nested for space-saving storage. The pipette tips in the disposable refill packs are configured to fit onto a mounting shaft that includes a pipette tip collar and a locking lobe that protrudes circumferentially. The pipette tips include a circular cantilever seal ring that seals laterally against the mounting shaft when the tip is fully mounted. The circular cantilever seal ring has an annular wall surrounded by a gap. The annular wall has an inner surface that slopes inward, providing a lateral interference fit with the mounting shaft. When the pipette tip is mounted on the mounting shaft, the annular wall curves radially outward in the direction of the gap rather than stretching, thereby reducing the required insertion force. Even when loading 384 pipette tips simultaneously in an automated liquid handling system, the cumulative insertion force is reduced, allowing the refill packs to be made with even less plastic.

Description

Technical Field

[0001] The present invention relates to pipette tips and racks, and more particularly to environmentally friendly disposable tip containers. The environmentally friendly disposable tip containers can be loaded with an array of pipette tips into a matrix of fittings or mounting shafts of robotic (e.g., automated or semi-automated) liquid handling devices when used in combination with a reusable structural base. The present invention relates in part to the configuration of a disposable pipette tip and a mounting shaft, and while achieving a robust seal engagement with low insertion force and low ejection force, securely and stably holds the attached pipette tip to each mounting shaft during use. The low insertion force makes it possible to significantly reduce the plastic components of the rack configuration.

[0002] This application claims the benefit of priority of U.S. Provisional Patent Application No. 63 / 490,891, filed on March 17, 2023. The entire contents of the application are hereby incorporated by reference.

Background Art

[0003] The use of disposable pipette tips in automated or semi-automated robotic liquid handling systems is well known. Disposable pipette tips allow for repeated use of the pipetting system without carryover contamination when transferring liquid reagents or liquid samples. Disposable pipette tips are typically formed from plastic materials such as polypropylene and have a hollow, elongated, generally conical shape. The upper end of the pipette tip includes a collar that attaches to the mounting shaft in the pipetting device. This mounting shaft is sometimes called a tip fitting. The mounting shaft or tip fitting contains an internal bore, which displaces air to draw liquid samples or reagents into the barrel of the pipette tip and then dispense the liquid samples or reagents, usually at another location. The end of the pipette tip has a small opening through which liquid samples or reagents are drawn into the barrel of the pipette tip and received there before being dispensed.

[0004] Conventionally, disposable pipette tips are secured and sealed to the mounting shaft by a tapered fit between the mounting shaft and the pipette collar, and a sealing ring positioned on the inner surface of the pipette collar. In the tapered fit, a seal is formed between the mounting shaft and the disposable tip by pushing the tapered mounting shaft into the tapered pipette collar until the mounting shaft fits onto the tip. At this point, a seal is achieved between the frustoconical tip collar and the mounting shaft as a result of crushing the sealing ring on the mounting shaft and / or extending the diameter of the collar.

[0005] In addition to achieving proper sealing, it is crucial that the position and orientation of the attached pipette tip remain stable against lateral moments (momentum) and light impact forces typical of normal use, such as when contacting the side wall of a sample container. In automated liquid handling systems, minimizing insertion and dispensing forces is desirable. This is often the case when systems are configured to simultaneously insert and dispensing 96 or 384 pipette tips. Reducing insertion and dispensing forces allows for a reduction in the size of the motor drive unit used in automated liquid handling systems, mitigates system deformation, improves the z-direction positional accuracy of the tips, enhances system reliability, and reduces the amount of material and packaging required for the tip rack.

[0006] Various systems have been devised that ensure proper sealing and stability without requiring excessive insertion or ejection force. U.S. Patent No. 6955077, "Pipette tip with internal sleeve and method for manufacturing the same." U.S. Patent No. 7047828, "Pipette tip with internal sleeve and stabilizing projection." All of these patents, by Blazczak et al., envision pipette tips having a branched or forked sidewall portion that extends upward in an annular shape and functions to seal the pipette tip against the mounting shaft. The branched portion that forms the seal protrudes slightly inward from the tip wall when relaxed. When a conical mounting shaft is pushed onto the pipette tip, the shaft contacts the branched portion and is pressed laterally against it, forming a seal between the pipette tip and the shaft. While these patents claim to reduce the insertion force required to achieve a sealing effect equivalent to that of a standard pipette tip, the conical mounting shaft still needs to be inserted with sufficient force and depth to securely fix the tip onto the tapered mounting shaft. In short, while these patents describe a lateral seal, the tapered mounting shaft still needs to be pushed with sufficient force into the collar portion of the tapered tip so that the tip is securely fixed and stable on the mounting shaft. These patents also claim to reduce potential discharge force, but the discharge force depends on how much force was used when initially mounting the pipette tip.

[0007] The applicant of this application has developed a highly reliable and ergonomically designed pipette tip attachment system, which is broadly described in the following patent: U.S. Patent No. 7,662343, titled "Locking Pipette Tip and Mounting Shaft," was issued on February 16, 2010. U.S. Patent No. 7,662344, titled "Locking Pipette Tip and Mounting Shaft," was issued on February 12, 2010. U.S. Patent No. 8,277,757, titled "Pipette Tip Mounting Shaft," was issued on October 2, 2012. U.S. Patent No. 8501118, titled "Disposable Pipette Tips," was issued on August 6, 2013. U.S. Patent No. 8877513, titled "Method of Use for Disposable Pipette Tips," was issued on November 4, 2014. U.S. Patent No. 9,333,500, titled "Locking Pipette Tip and Mounting Shaft for Handheld Manual Pipettes," was issued on May 1, 2016. These are all incorporated herein by reference. In these patents held by the applicant, the tip mounting shaft includes a locking section having a locking lobe located above a stop and projecting outward with circumferential space, the stop consisting of a step, the step spanning between the locking section of the mounting shaft and a lower sealing section of the mounting shaft with a smaller diameter. The tip collar is locked to the mounting shaft when the mounting shaft is fully inserted into the collar of the corresponding disposable pipette tip. The bore of the pipette tip includes a circumferential shelf or shoulder separating the upper collar from the tip sealing area, the tip sealing area located within the barrel of the tip below the circumferential shelf. The tip collar includes a locking ring at or near the upper opening of the collar into which the mounting shaft is inserted. The dimensions of the collar, in particular the distance between the circumferential shoulder and the locking ring, are selected to match the dimensions between the stop of the mounting shaft and the tip catching surface of the locking lobe, thereby locking the pipette tip in a secure and reliable position and orientation. The locking lobe includes a sloping ramp portion, which bends and distorts the tip collar from its circular shape as the mounting shaft is inserted into the pipette tip beyond the locking ring. This reduces the insertion force required to mount the tip, as it does not stretch the tip collar. A preferred tip mounting shaft has three or more lobes spaced evenly around the mounting shaft, with concave relief portions spanning between the lobes formed to accommodate the inward distortion of the tip collar between the lobes. As described above, the lobes include a sloping ramp that slopes gently at an angle of 10 to 20 degrees with respect to the vertical axis of the mounting shaft. Each lobe extends outward along the ramp towards the top of the locking section of the mounting shaft, then curves inward to form a catch surface. In some embodiments, a descending ramp is provided on the portion of the lobe beyond the peak, reducing the required discharge force compared to a steep catch surface.When the mounting shaft is fully inserted into the pipette tip, the locking ring of the pipette collar engages with the catch surface or descending ramp as it fits onto the peak of the lobe, ensuring a secure snap-on attachment. Preferably, the peak of each lobe is slightly rounded to facilitate removal of the pipette tip.

[0008] When the mounting shaft is inserted into the pipette tip, the tip collar of the pipette tip bends and deforms into a non-circular shape, while the peripheral shoulder between the collar and the tip barrel isolates the sealing area at the upper end of the barrel from distortion. This structural isolation by the peripheral shoulder of the tip facilitates a reliable seal engagement between the lower sealing area of ​​the tip mounting shaft and the sealing area at the upper end of the tip barrel. In some embodiments, a seal ring extends inward from the upper end of the tip barrel of the pipette tip below the peripheral shoulder and engages in an interference fit with the sealing area below the stop of the mounting shaft. In other embodiments, the mounting shaft has a groove below the stop that holds the seal ring, such as an elastic O-ring. When the mounting shaft is fully inserted into the tip, the O-ring on the mounting shaft engages with the sealing area at the upper end of the tip barrel. O-rings are generally used with larger tips, which typically have greater insertion forces than smaller tips, to further reduce the insertion force. In either of these cases, the seal ring or seal area at the upper end of the tip barrel is isolated from the strain by the structural strength of the circumferential shoulder of the pipette tip between the distorted lock collar and the circular tip barrel.

[0009] As described in the patent owned by the above applicant, the combination of the locking lobe and the stop on the mounting shaft provides an ergonomically designed over-center locking mechanism that notifies the user of a handheld pipette with tactile feedback that the disposable pipette tip is approaching the mounting shaft and is fully mated. When used in automated liquid handling systems, the over-center locking mechanism provides precision, robust mounting, and sealing of the tip array. When the mounting shaft is pushed into the tip collar, the first contact point is where the tip edge of the mounting shaft, i.e., the lower sealing area, passes over the peripheral shoulder of the pipette tip and contacts the sealing area of ​​the tip barrel. As the mounting shaft is further pushed into the bore of the pipette tip, interference with the seal increases, and the rising inclined surface of the locking lobe on the mounting shaft engages with the tip collar, distorting the upper portion of the collar into a non-circular shape. The overall insertion force is relatively light and ergonomic compared to the technology of the time, but the force increases significantly until the stop member of the mounting shaft contacts the peripheral shoulder of each pipette tip and the relative movement of the mounting shaft to the tip abruptly stops. At this point, the lobe snaps under the locking ring in the collar, and the tip is securely fixed and held in place on the mounting shaft by, for example, the tip of the locking ring engaging with the catch surface or descending ramp of the lobe. These interrelated mounting conditions result in a secure, stable mounting and a consistent seal. Furthermore, energy is stored in the collar during mounting as it bends into a distorted shape. To eject the tip from the mounting shaft, a downward ejection force is required to release the locking ring in the collar from the locking lobe on the mounting shaft. Generally, the downward ejection force further distorts the lobes of the collar outward, allowing the locking ring to slide down the peaks of each lobe and be released. When the tip is released from the lobe, the downward force from the pipette tip release mechanism, combined with the energy stored in the distorted tip collar acting on the shape of the lobe, creates a tendency for the tip to be ejected from the mounting shaft. This facilitates the easy removal of the tip from the mounting shaft after use.While the tip mounting system described in the applicant's previous patent represents a significant technological advancement, it is desirable to further reduce the tip insertion force without substantially compromising the stability of the mounted pipette tip.

[0010] A pipette tip rack is a device that organizes pipette tips for easy attachment to pipette mounting shafts and fittings. Racks typically contain a plastic tip insert with an array of holes, such as an 8x12 or 16x24 array, through which pipette tips are suspended, with the tip collar exposed upwards. Conventional racks for automated liquid handling systems include a substantially rigid box that suspends the plastic tip insert at a sufficient height for pipette tips to pass through the holes and be suspended by their tip collars. The rigidity of the box is important for holding the tips in a stable position when loading them onto the mounting shaft of the automated instrument. Typically, multiple reinforcing support ribs extend upwards from the bottom of the box, supporting the plastic tip insert from below. This support structure is particularly important to prevent the plastic tip insert from bending in the middle due to the accumulated load when loading 384 tips simultaneously onto the mounting shaft array, if left unsupported or undersupported. Due to the bending, some chips may not be properly mounted. When loading 96 chips simultaneously, the overall load is usually not very large, but most designs require one or more support reinforcing ribs.

[0011] The tip rack typically has a transparent, removable cover which is removed before loading the tips into the array of mounting shafts. The liquid handling device includes, for example, a "nest" with SBS standard dimensions, and the user sets the tip rack into this nest before loading the tips into the array of mounting shafts. The array of holes for the plastic tip inserts is usually arranged according to SBS standard dimensions (9mm centerline spacing for 96 tips, 4.5mm for 384 tips), so that the automated liquid handling device can lower the pipette head together with the array of mounting shafts and load the tips simultaneously.

[0012] The use of rigid tip racks generates a large amount of plastic waste in the laboratory. Some laboratories choose to purchase tips in bulk bags for manual reloading of used tip racks. However, this method is time-consuming and unsuitable for sterile applications. It is also known that refill packs are sold with tips filled into plastic tip inserts without a bottom receptacle for the rack. These refill packs are manually filled by the user into used tip racks or reusable bases. While refill packs without a bottom receptacle are convenient for many customers, they are undesirable in highly sterile environments. It is known that multiple refill packs are stacked and packaged by partially nesting the tips of the upper refill pack into the tips of the lower pack. With refill packs of tips packaged on cardboard, paper fragments can interfere with experiments. Many customers requiring sterile pipette tips and packaging have no choice but to use rigid tip racks that can withstand the cumulative mounting force when mounting tips on 96 or 384 mounting shafts in a robotic system. This can result in a large amount of waste that needs to be stored in a laboratory before disposal or recycling.

[0013] The applicant owns U.S. Patent No. 11850596, issued on December 26, 2023, by Bonnoitt et al., entitled “Pipette Tip Rack System.” The Bonnoitt patent discloses the use of a pipette tip dispenser mounted on a laboratory benchtop, which includes a reusable thermoformed container filled with pipette tips for loading tips into a handheld pipette. Both the container and the tip dispenser have hinged covers or lids that allow the container to remain closed while the user loads tips into the handheld pipette. Configurations are also known that provide a reusable base (without a hinged cover) for reusable pipette tip containers intended for handheld use. The Bonnoitt patent system, in general, does not have sufficient strength to withstand the forces generated in applications involving automated robots. Similarly, other companies are manufacturing recyclable or disposable tip containers supported by rigid, reusable bases, but these systems are intended for use with handheld pipettes, where the cumulative load force is significantly lower compared to automated robotic systems. [Overview of the project]

[0014] The present invention relates to a pipette tip rack system for packaging pipette tips in disposable refill packs configured to maintain the pipette tips in a sterile state until use in the laboratory. The refill packs are set on a robust, reusable base, which is placed in a nest of automated or semi-automated liquid handling equipment for loading the tips. Preferably, the bottom peripheral wall of the reusable base has outer nesting dimensions in accordance with SBS standards. After use, the refill packs are easily disassembled, and their components (receptor, support ribs, plastic tip insert, cover) can be stored in a space-saving manner by nesting or stacking before recycling or disposal. When loading 96 or 384 tips simultaneously, it is necessary to reduce the tip insertion force in the background art in order to maintain the structural strength of the disposable refill pack and prevent the plastic tip insert from bending.

[0015] Therefore, the pipette tip, the disposable refill pack including the plastic tip insert, and the reusable base are a system that functions only in combination. The inventors have configured the pipette tip to sufficiently reduce the tip load force so that when the refill pack is placed on the reusable base, it allows for a reduction in the weight of the refill pack without sacrificing the stability of the refill pack or the plastic tip insert. The refill pack is not configured to withstand the load force of liquid handling equipment, especially those with 96 or 384 heads. Therefore, the strength and stability required to withstand the load force that needs to be withstood are primarily provided to the system from the reusable base.

[0016] The inventors have configured pipette tips to reduce the tip loading force sufficiently to enable reliable use when combining the disposable refill pack described in the claim with the reusable base described in the claim during robotic loading of 96 or 384 tips. In the future, other mounting shaft / tip configurations or materials may be discovered to reduce the required insertion force. Similarly, disposable refill packs configured according to the present invention would be useful in such situations.

[0017] The pipette tip rack system is configured for use with robotic liquid handling systems, but can also be used handheld upon request.

[0018] The refill packs mentioned above are configured to be disposable, and when the refill packs are loaded simultaneously into an array of 96 or 384 pipette tips in a reusable base, the reusable base supports the periphery of the plastic tip inserts, and removable support ribs support the center of the plastic tip inserts. The refill packs have a tip receptacle or liner with bottom, side, front, and back walls. The plastic tip inserts straddle wells and have a peripheral skirt supported by the side walls of the tip receptacle for packaging purposes. The tip receptacle defines wells below the plastic tip inserts for housing the barrel portions of pipette tips. The plastic tip inserts have an array of holes for holding the array of pipette tips, with the centerlines of each hole spaced 4.5 mm apart in the case of an array of 384 pipette tips and 9 mm apart in the case of an array of 96 pipette tips. This is the standard in the art. The pipette tips are held nearly vertically, with the collar at the top of each tip facing upward, which facilitates mounting the pipette tips to an array of pipette mounting shafts in a robotic liquid handling system or, as required, to a handheld pipette. The plastic tip inserts are detachably connected to the tip receiver and can be easily disassembled and stacked after the pipette tips are mounted and removed from the tip rack system.

[0019] The removable cover of the disposable refill pack covers the plastic tip insert and the color of the pipette tip held by the plastic tip insert. The cover and tip receptacle keep the pipette tip sterile when the tip is intended to be sterile. Preferably, the cover is transparent or clear so that the user can see the pipette tip and the color of the plastic tip insert. Preferably, the colors of the plastic tip inserts are coded to represent the size and / or type of mounting shaft compatible with the pipette tip.

[0020] Vertical support ribs are positioned within the wells of the chip receiver. These vertical support ribs are set in one or more vertical rib mounts extending upward from the bottom wall of the chip receiver. Preferably, one mount is located on the front side and one on the rear side, and these mounts are integrally molded with the bottom wall and their respective front or rear walls. The vertical support ribs extend vertically from the bottom wall of the chip receiver to the bottom surface of the plastic chip insert. When the refill pack is disassembled after use, these vertical support ribs are removable from the vertical rib mounts and the chip receiver. After being removed from the mounts, the vertical support ribs can be laid flat within the wells of the chip receiver, facilitating stacking and nesting of used chip receivers.

[0021] The refill pack is set in a reusable base, and when the pipette tip is attached to the array of pipette mounting shafts in a robotic liquid handling system, the side walls of the base support the peripheral skirt of the plastic tip insert. When the pipette tip is attached to the array of pipette mounting shafts in the robotic liquid handling system, the bottom wall of the reusable base supports vertical support ribs, which in turn support the bottom surface of the plastic tip insert. The vertical support ribs prevent the plastic tip insert from bending due to accumulated load pressure. Preferably, the vertical support ribs are positioned equidistant from both side walls of the tip receiver.

[0022] In a preferred embodiment of the present invention, the plastic tip insert has several structural features that facilitate the precise positioning of the refill pack in the reusable base and facilitate the convenient disassembly of the refill pack after use. The tip receiver has a peripheral horizontal rim extending outward from the top of the side wall. This peripheral rim has snap-fit ​​holes adjacent to each side wall for snap-fitting with the plastic tip insert. The snap-fit ​​has a groove on its outer surface that receives the peripheral rim of the tip receiver and also has a vertical slot, and can be compressed on each side to secure the plastic tip insert to the peripheral rim of the tip receiver and to remove it after use. The side walls of the reusable base include holes at the top of each side wall corresponding to the snap-fitting with the plastic tip insert, although it is desirable that the ends of the snap-fit ​​not snap-engage with the reusable base even when fitted into the holes. Preferably, the plastic tip insert is further provided with guide posts extending from the peripheral skirt near the corners to facilitate proper alignment of the refill pack when inserting it into the reusable base. Preferably, the side walls of the reusable base are provided with guide holes for corresponding guide posts at the top of each side wall.

[0023] The plastic chip inserts are configured to be stackable when disassembled from the chip receiver. For example, preferably, the top of the plastic chip insert has an enlarged recess to capture the snap fittings and guide posts of plastic chip inserts stacked on top of it. Also, to further facilitate space-saving stacking, preferably, the outer surfaces of the opposing side walls of the chip receiver have vertical stacking ribs that extend partially downward from the peripheral rim to each side wall. The reusable base has slots for these vertical stacking ribs and also serves to stabilize the chip receiver within the reusable base when loading chips.

[0024] As described above, the structure of the replenishment pack can be used only when the cumulative load gravity does not bend the plastic chip insert. The exemplary 384 replenishment packs shown in FIGS. 18 to 34 can withstand a cumulative load gravity of 3072 N (maximum load gravity of 8 N per 125 μl chip) without damage to the plastic chip insert or the vertical support ribs. The 125 μl chips in the background art or chips of equivalent size cannot withstand a load of less than 8 N. Therefore, the chip rack for the chips in the background art needs to withstand a cumulative load much higher than the 3072 N that the exemplary 384 replenishment packs shown in FIGS. 18 to 34 can withstand. In the case of a larger pipette tip, for example, a 1250 μl tip or a tip of equivalent size, the seal configuration of the invention results in a maximum load gravity of 10 N per 1250 μl chip. The 1250 μl chips are packaged in an array of 96 chips, such as the exemplary 96 replenishment packs shown in FIGS. 35 to 42. This pack is taller than the exemplary 384 replenishment packs shown in FIGS. 18 to 34 but is configured to withstand a cumulative load gravity of at least 960 N. As described above, the inventor has created a pipette tip with a sufficiently reduced chip load gravity so that the disposable replenishment pack of the claims can be used reliably when loading 96 or 384 chips robotically. Exemplary embodiments of the improved pipette tip are described with reference to FIGS. 2 to 17.

[0025] The improved pipette tip is configured to be mounted on a mounting shaft or tip fitting having outwardly projecting lock lobes spaced circumferentially. In the patent owned by the above-mentioned patent holder (assignee), the pipette tip is sealed against the mounting shaft below the peripheral shoulder of the tip, between the tip collar and barrel. In other words, the seal occurs on the upper portion of the tip barrel. The improved pipette tip is modified to have a circular cantilever seal ring at the peripheral shoulder between the tip collar and barrel. The circular cantilever seal ring has a laterally elastic annular seal wall extending from the peripheral shoulder of the pipette tip toward the opening of the collar, and also has a vertex, the vertex of which abuts against the stop of the mounting shaft, providing tactile feedback that the pipette tip is fully mounted, so that the user does not use excessive force in an attempt to press the pipette tip more tightly against the mounting shaft. The annular seal wall of the cantilever seal ring slopes slightly inward as it extends upward from the base. When the mounting shaft is inserted, the upper portion of the annular seal wall displaces laterally and radially outward, forming a lateral interference fit seal with respect to the mounting shaft directly below the stop on the mounting shaft. An annular gap exists between the annular seal wall and the tip collar. This gap allows the annular seal wall to move laterally outward without the need for the collar to stretch, reducing the required insertion force compared to pipette tips in the applicant's background art. Furthermore, preferably, the sealing region of the mounting shaft is cylindrical. Preferably, the inner diameter directly below the annular seal wall in the cantilever ring seal is selected to have zero interference with the cylindrical sealing region of the mounting shaft, thereby further reducing the required insertion force.

[0026] A pipette tip incorporating a circular cantilever seal ring has been found to have significantly reduced insertion and ejection forces compared to conventional pipette tips manufactured by the applicant. In the case of larger chips, it may be desirable to use an O-ring in the seal area of the mounting shaft to further reduce the insertion force. However, the structure of the circular cantilever seal ring assumes that even for larger chips, the O-ring becomes unnecessary because it significantly reduces the insertion force compared to conventional sealing methods.

[0027] The circular shape of the base of the circular cantilever seal ring is maintained even when the peripheral shoulder at the periphery of the pipette tip locks the non-circularly distorted collar to the lobe of the mounting shaft. Similar to the applicant's previous pipettes, each locking lobe on the mounting shaft of the pipette tip includes a portion of an inclined ramp that slopes outward as the inclined ramp extends upward along the mounting shaft. The purpose of the inclined ramp portion of the lobe is to facilitate the non-circular distortion of the collar of the pipette tip as the mounting shaft is inserted into the pipette tip. The relief portion spanning between the portion extending outside the lobe and the portion recessed with respect to the lobe accommodates the inward distortion of the collar of the pipette tip between the lobes, as in the background art. Thus, when the pipette tip is attached to the mounting shaft according to the present invention, the collar of the pipette tip is non-circularly distorted, but the peripheral shoulder of the pipette tip between the collar and the barrel remains substantially circular and undistorted. The structural strength of the peripheral shoulder in the tip maintains the circular and undistorted shape of the base of the circular cantilever seal ring.

[0028] Preferably, each locking lobe includes a peak portion located at the maximum outer distance from the longitudinal axis of the mounting shaft, and a descending ramp portion that extends upward along the mounting shaft from the peak of the lobe and is angled inward toward the longitudinal axis of the mounting shaft. However, the present invention can be implemented with a mounting shaft having a catch surface on the locking lobe that is steeper than the gently sloping descending ramp. Preferably, the mounting shaft has three or more locking lobes. It is preferable that the locking lobes occupy less than 15% of the circumference of the mounting shaft at the peak portion of the locking lobe, and the remaining circumference of the mounting shaft is occupied by relief portions between the lobes. This configuration with relatively thin locking lobes helps reduce friction between the tip collar and the mounting shaft, reducing insertion and ejection forces, while simultaneously achieving stable over-center mounting of the tip to the lobe.

[0029] The pipette tips shown in Figures 2 through 17 can be used in combination with handheld, single-channel, and multi-channel pipettes, and can also be used in combination with automated and semi-automated liquid handling equipment that loads arrays or matrices of multiple disposable pipette tips simultaneously under robotic control. The use of stops on the mounting shaft and the lobes described ensures that each pipette tip is mounted at the same height and properly aligned in multi-channel applications. As will be described in detail below with reference to the drawings, the pipette tip and mounting shaft configuration of the present invention reduces the required insertion and dispensing forces without substantially affecting the stability of the tip mounted on the mounting shaft under normal operating conditions. This reduction in load forces allows for simultaneous loading of tips using the disposable refill packs described above, even when 384 pipette tips are housed in a package.

[0030] With reference to the attached drawings, other aspects, features, and advantages of the invention will be described in further detail. [Brief explanation of the drawing]

[0031] [Figure 1] This invention illustrates a manually operated 384-well robotic pipetting apparatus using pipette tips and a pipette tip rack system configured according to the present invention. [Figure 2] A perspective view showing a disposable pipette tip and tip mounting shaft configured according to an exemplary embodiment of the present invention. [Figure 3] Figure 2 is a side elevation view of the mounting shaft and pipette tip shown. [Figure 4] This is a longitudinal cross-sectional view obtained along line 4-4 in Figure 3. [Figure 5] This is a detailed view of the area enclosed by line 5-5 in Figure 4, showing the upper lock collar, peripheral shoulder, and circular cantilever seal ring of a disposable pipette tip. [Figure 6] This is a detailed view of the area enclosed by line 6-6 in Figure 4, showing the locking section, cylindrical seal section, and stop in the tip mounting shaft. [Figure 7] This is a side view showing the mounting shaft inserted into a disposable pipette tip. [Figure 8] This is a longitudinal cross-sectional view obtained along line 8-8 in Figure 7. [Figure 9] This is a detailed view of the area enclosed by line 9-9 in Figure 8, showing that the mounting shaft is inserted into the pipette tip just before final engagement. [Figure 10] This is a detailed view similar to Figure 9, showing the mounting shaft fully inserted into the pipette tip. [Figure 11] This is a cross-sectional view obtained along line 11-11 in Figure 10, showing the non-circular deformation of the pipette tip collar and lock ring when the pipette tip is fully attached to the mounting shaft. [Figure 12] Similar to Figure 10, this shows the pipette tip being discharged from the mounting shaft. [Figure 13a]This schematic diagram illustrates the interaction that occurs between the annular wall of the circular cantilever seal ring at the pipette tip and the cylindrical seal region at the pipette mounting shaft as the mounting shaft is inserted into the tip collar. [Figure 13b] This schematic diagram illustrates the interaction that occurs between the annular wall of the circular cantilever seal ring at the pipette tip and the cylindrical seal region at the pipette mounting shaft as the mounting shaft is inserted into the tip collar. [Figure 13c] This schematic diagram illustrates the interaction that occurs between the annular wall of the circular cantilever seal ring at the pipette tip and the cylindrical seal region at the pipette mounting shaft as the mounting shaft is inserted into the tip collar. [Figure 14] This is an enlarged cross-sectional view of a disposable pipette tip molded according to an exemplary embodiment of the present invention, showing a circular cantilever seal ring and a stabilizing ring. [Figure 15] Data is presented (published) showing that using a tip mounting shaft and disposable pipette tip configured according to an exemplary embodiment of the present invention significantly reduces insertion force. [Figure 16] Another exemplary embodiment of a mounting shaft having an O-ring in the sealing region of the mounting shaft is shown. [Figure 17] This shows a structural analysis of a tip configured according to an exemplary embodiment of the present invention, which is subjected to lateral displacement at the tip's dispensing end, as is typical in pipetting procedures when releasing the tip. [Figure 18] This is a perspective view of a pipette tip rack system for a robotic liquid handling system configured according to a first embodiment of the present invention. [Figure 19] Figure 18 is an assembly diagram of the chip rack system shown. [Figure 20] This is a perspective view of a disposable tip refill pack inserted into a reusable base, according to one aspect of the invention. [Figure 21]This is a perspective view of a disposable tip receiver or liner configured according to an exemplary first embodiment of the present invention. [Figure 22] Figure 21 is a side elevation view of the disposable chip receiver shown. [Figure 23] Figures 21 and 22 are top views of the disposable tip receiver. [Figure 24] This is a top perspective view of a plastic chip insert configured according to an exemplary first embodiment of the present invention. [Figure 25] Figure 24 is a bottom perspective view of the plastic chip insert shown. [Figure 26] Figures 24 and 25 are top views of the plastic chip inserts shown. [Figure 27] This is a detailed diagram showing how to insert a disposable tip refill pack into a reusable base. [Figure 28] This is a perspective view of a disposable tip refill pack of a first embodiment, with the cover removed to allow the pipette tip to be attached to a robotic liquid handling system, the pipette tip loaded into a plastic tip insert, and set on a reusable base. [Figure 29] Figure 28 shows a disposable tip refill pack mounted on a reusable base, with the pipette tip attached and then removed. [Figure 30] This is a cross-sectional view along line 30-30 in Figure 29. [Figure 31] This is a perspective view showing a plastic insert removed from a disposable tip receiver. [Figure 32] This is a perspective view of a disposable tip receiver with the removable vertical support ribs removed. [Figure 33] This is a schematic diagram showing a stack of disposable chip receivers configured according to an exemplary first embodiment of the present invention, compared to a stack of racks in the background technology. [Figure 34] This is a cross-sectional view obtained along line 34-34 in Figure 33, showing a stack of disposable chip receptors. [Figure 35] This is a perspective view of a pipette tip rack system for a robotic liquid handling system configured according to an exemplary second embodiment of the present invention. [Figure 36] Figure 37 is an assembly diagram of the pipette tip rack system shown. [Figure 37] This is a side elevation view of a disposable tip receiver configured according to an exemplary second embodiment of the present invention. [Figure 38] Figure 40 is a plan view of the disposable tip receiver shown. [Figure 39] Figures 37 and 38 show the bottom perspective views of the disposable tip receiver. [Figure 40] This is a top view of a plastic tip insert configured according to an exemplary second embodiment of the present invention to hold 96 pipette tips. [Figure 41] Figure 40 is a bottom perspective view of the plastic chip insert shown. [Figure 42] This is a cross-sectional view showing the components of a chip rack system configured according to a second embodiment of the present invention. [Figure 43] This is a schematic diagram showing a stack of disposable chip receivers configured according to an exemplary second embodiment of the present invention, compared to a stack of racks in the background technology. [Figure 44] This is a cross-sectional view of a stack of disposable chip receptors obtained along line 44-44 in Figure 43. [Modes for carrying out the invention]

[0032] Figure 1 shows a manually operated 384-channel robotic pipetting system 10. Details of how the robotic pipetting system 10 operates are disclosed in the following patent. U.S. Patent No. 8,367022, issued on February 5, 2013, by Warhurst et al., entitled "Unintended Operation Control of Manually Operated Multi-Channel Electronic Pipettes." U.S. Patent No. 8,372,356, issued on February 12, 2013, by Warhurst et al., is titled "Manually Operated Multi-Channel Electronic Pipetting System". These are all incorporated herein by reference. In summary, the robotic pipetting system 10 is shown with a pipette head attached to the system 10, accompanied by an array of 384 disposable pipette tips 14 attached to an array (16 × 24) of mounting shafts 12. The tip mounting shafts 12 are configured according to exemplary embodiments of the invention described below. The disposable pipette tips 14 are configured similarly. When simultaneously attaching the array of pipette tips 14 to the array of mounting shafts 12, the required cumulative insertion force is significantly greater than that of a single-channel handheld pipette, or even an 8, 12, or 16-channel handheld pipette. In fact, the cumulative insertion force for simultaneously attaching 384 tips is significantly greater than that for 96 tips, although the invention is intended to relate to a 96-channel system as well as a 384-channel system. The robotic pipetting system 10 shown in Figure 1 includes a vertical drive mechanism used to move the pipette head up and down to generate sufficient force for simultaneous insertion into 96 or 384 tips. Whether manually controlled, as in system 10 in Figure 1, or fully automated, like many other laboratory liquid handling systems, it is known that robotic pipetting systems have a vertical drive mechanism that raises and lowers the pipette head to generate sufficient force to insert 96 or 384 pipette tips simultaneously. The pipette tip rack system 20, pipette tips 14, and mounting shaft are useful in fully automated laboratory liquid handling systems, including semi-automatic manual operation systems as shown in Figure 1. The pipette tip rack 20 can also be used for handheld pipetting, but the rack 20 is particularly configured to withstand the demanding conditions of simultaneous loading of multiple arrays of pipette tips in robotic systems.

[0033] The robotic pipetting system 10 shown in Figure 1 comprises a flat deck 17 supporting a right-side nesting receptor 19 and a left-side nesting receptor 21. The nesting receptors 19 and 21 are configured to hold microtiter plates, reagent reservoirs, or pipette tip racks in known positions on the deck 17. Preferably, the nesting receptors 19 and 21 have dimensions defined by the SBS standard in known art. Figure 1 shows a pipette tip rack system 20 configured according to an exemplary first embodiment of the present invention, the pipette tip rack system 20 being set in the left-side nesting receptor 21. The pipette tip rack 20 holds 384 pipette tips, which are mounted on pipette heads fixed to a carriage 22 of the robotic pipetting system 10 in Figure 1. The carriage 22 is mounted on a tower 24. In some systems, the pipette head is interchangeable, allowing the user (customer) to switch between a 384-channel head and a 96-channel head as needed. A pipetting motor located in the carriage 22 drives the multi-channel pipette head for aspiration and dispensing. A Z-axis vertical drive mechanism moves the carriage 22 and the multi-channel pipette head vertically to the tower 24 and deck 17. An X-axis drive mechanism moves the tower 24 and carriage 22 horizontally along the X-axis, thereby moving the pipette head and tip array 14 to the top of the right-side nesting receptor 19 or the left-side nesting receptor 21 on the deck 17.

[0034] System 10 is mounted on a carriage 22 and features a control handle 16 shaped like the handle of a handheld electronic pipette. During use, the user grips the control handle 16 in the same manner as when using a handheld pipette, applying pressure to the control handle 16 to direct the movement of the carriage 22 and the pipette head. Vertical Z-axis movement and horizontal X-axis movement are driven by independent motors under servo control. Furthermore, the control handle 16 in System 10 includes a user interface for controlling pipette functions such as aspiration and dispensing.

[0035] To attach pipette tips, the pipette head, along with the array of tip mounting shafts, is precisely positioned on top of the tip rack 20 located on deck 17 using the X-axis horizontal drive mechanism. Next, the carriage 22 and tip mounting shafts 12 are lowered with sufficient force using the Z-axis vertical drive mechanism to attach the array of pipette tips 14 held in the tip rack 20. Then, the carriage 22 and pipette head are raised using the Z-axis vertical drive mechanism to remove the pipette tips 14 from the tip rack 20. The tip rack 20 is removed from the nesting receiver 21 on deck 17 and replaced with a well plate or reservoir for transferring liquid.

[0036] For tip mounting as a normal motion control, the general horizontal and vertical movement of the carriage 22 and pipette head is controlled by the user holding the controller 16 in their palm and applying pressure in the appropriate direction to position the pipette head on the rack 20 of pipette tips 14. By using biased motion control software, the precise alignment required for tip mounting can be achieved. After the pipette head and tip mounting shaft 12 are aligned, the handle control 16 is disabled. An automatic tip mounting routine is executed, which applies sufficient downward force to secure the pipette tip 14 to the mounting shaft 12 and further lowers the mounting shaft to the appropriate height. As a safety measure, the automatic tip mounting routine is only enabled if it is detected that one of the user's hands is pressing the button 25 on the top of the carriage 22 and the other hand is on the handle 16.

[0037] The internal components within the carriage 22 each drive pistons extending through seal assemblies, displacing air in the suction and discharge cylinders. The tip mounting shaft 12 is fixed to the pipette head, thereby enabling each shaft to fluidly communicate with one of the suction and discharge chambers. The user interface on the handle 16 includes a thumbwheel control, a travel button, and a display. The handle 16 further includes a lever or discharge button 18 that is pushed downward to enable downward movement of the discharge plate at the pipette head. Preferably, the discharge plate is actuated in steps to discharge the tip in stages, thereby reducing the required discharge force.

[0038] The pipette tip rack system 20 shown in Figure 1 holds 384 pipette tips 14 and is a first embodiment of the pipette tip rack system, which is shown in more detail in Figures 18 to 36. A second embodiment of the pipette tip rack system 301 is shown in Figures 35 to 42 and holds 96 pipette tips 14. As described above, the tip rack system uses disposable tip refill packs and a reusable base and provides sufficient strength to hold the plastic tip inserts horizontally, even when 96 or 384 pipette tips 14 are mounted simultaneously. In one aspect, the present invention relies on the use of a mounting shaft and pipette tip pair that requires relatively low insertion force. The mounting shaft 12 and pipette tip 14 shown in Figures 2 to 17 provide low insertion force and a robust and reliable seal.

[0039] As shown in Figure 2, the mounting shaft 12 in this exemplary embodiment has threads 26 that secure to the lower end of a suction / discharge cylinder (not shown) located in the pipette head of a robotic liquid handling system 10. The dimensions of the mounting shaft 12 are configured to match the dimensions of the pipette tip 14, so that only pipette tips 14 with the appropriate dimensions fit and engage properly with the mounting shaft 12. For example, if a pipette tip is configured according to the present invention, but the user chooses to use a pipette tip with different bore dimensions in the collar or seal area, the pipette head needs to be replaced with a new pipette head with a mounting shaft 12 that has dimensions suitable for the pipette tip 14 to be mounted and used. Preferably, the pipette head and tip storage rack are color-coded so that the user can easily identify that the tip is a tip of the present invention (of the applicant, assignee's) and has a collar that fits the mounting shaft. Color coding can be achieved by color-coding the configuration of various plastic tip inserts.

[0040] Referring to Figures 2 to 6, as is well known to those skilled in the art, the mounting shaft 12 includes a central bore 28 (Figure 6) that allows air to pass between the aspiration / discharge cylinder of the pipette 10 and the pipette tip 14. The pipette mounting shaft 12 includes an upper locking section 30, a lower section 32, and a stop 34 located between the upper locking section 30 and the lower section 32. A seal is formed in a region 55 of the lower section 32 directly below the stop 34 (see Figure 6). The locking section 30 of the mounting shaft 12 has outwardly projecting locking lobes 50 and a concave region 58 (see, for example, Figure 6) positioned to straddle the locking lobes 50.

[0041] The pipette tip 14 as a whole comprises a tip collar 36, a tip barrel 38, and a peripheral shoulder 40 (see, for example, Figures 4 and 5), the peripheral shoulder 40 extending around the inner bore of the pipette tip 14 and connecting the lower end of the tip collar 36 to the upper end of the tip barrel 38. The upper end of the tip collar 36 has an opening 42 for receiving the pipette mounting shaft 12. The lower end of the tip barrel 38 has a small opening 44 (lower opening 44) that draws liquid into the tip barrel 38 and discharges it from the tip barrel 38 during normal operation of the pipette 10. Support ribs 46 (Figure 3) extend downward from the tip collar 36 on the outer surface of the disposable pipette tip 14. As is technically known, the support ribs 46 function to hold the pipette tip 14 or an array of pipette tips 14 in a rack for subsequent use or mounting.

[0042] Referring to Figure 5, a preferred configuration of the pipette tip 14 is described. Preferably, a circumferential locking ring 48 is positioned on the inner surface of the tip collar 36 of the pipette tip 14. The locking ring 48 is located at or slightly below the opening 42 in the tip collar 36 into which the mounting shaft 12 is inserted. The locking ring 48 protrudes slightly inward from the inner wall of the tip collar 36, preferably in the range of 0.025 to 0.25 mm, and is configured to provide an over-center lock fit to the peak 61 of the lobe 50 on the mounting shaft 12 (see Figure 6). The locking ring 48 may include an optional air bleed 52. However, such an air bleed is usually unnecessary because, when the tip is mounted, the deformation of the tip collar 36 should normally provide sufficient clearance to the concave area 58 on the mounting shaft 12. Preferably, the inner surface of the tip collar 36 may be cylindrical, but slightly tapered or slightly frustoconical. The preferred taper angle is between 0 and 10 degrees. In any case, the horizontal cross-section passing through the main section of the tip collar 36 is circular.

[0043] As described above, the peripheral shoulder 40 of the pipette tip 14 connects the lower end of the tip collar 36 to the upper end of the barrel 38. The circular cantilever seal ring 100 has an elastic annular wall 101 extending from the peripheral shoulder 40 of the tip toward the opening 42 of the collar. The purpose of the laterally elastic annular wall 101 is to engage and seal with the cylindrical seal area 55 (see Figure 6) on the mounting shaft 12 from the side when the pipette tip 14 is fully mounted on the mounting shaft 12. The annular wall 101 has a free end upper edge 102, which abuts against the stop 34 of the mounting shaft 12 when the pipette tip 14 is fully mounted on the mounting shaft 12. See, for example, Figures 9 and 10.

[0044] When the pipette tip 14 is attached to the tip mounting shaft 12, the tip collar 36 of the disposable pipette tip 14 has sufficient flexibility because it deforms outward at the lobes 50 on the mounting shaft 12 and inward at the concave relief portion 58 of the mounting shaft between the lobes. However, the peripheral shoulder portion 40 has sufficient structural strength to maintain the roundness of the circular cantilever seal ring 100, thereby sealing the inner surface 104 of the annular wall 101 laterally against the seal area 55 on the mounting shaft 12.

[0045] The peripheral shoulder 40 shown in Figure 5 is continuous along the periphery of the pipette tip 14. In exemplary embodiments, the shoulder 40 has an angle in cross-section, but it is not necessarily required to have an angle. The peripheral shoulder 40 provides structural strength that separates and isolates the deformation of the tip collar 36 from the circular cantilever seal ring 100. As most clearly shown in Figure 11, when the mounting shaft 12 is fully inserted into the pipette tip 14, the tip collar 36 deforms out of circle. The peripheral shoulder 40 of the pipette tip 14 isolates the circular cantilever seal ring 100 from this deformation, thereby facilitating an effective lateral seal between the inner surface 104 of the annular wall 101 of the circular cantilever seal ring 100 and the seal area 55 (not shown in Figure 11) when the mounting shaft 12 is around the entire periphery.

[0046] Referring again to Figure 5, when the pipette tip 14 is fully mounted on the mounting shaft 12, the stop 34 on the mounting shaft 12 engages with the upper edge 102 of the annular wall 101 of the circular cantilever seal ring 100 to precisely position the mounting height of the pipette tip 14 on the mounting shaft 12. In a multi-channel device, this configuration ensures that the vertical mounting distance between tips is the same, facilitating accurate and consistent adjustment of tip positioning during pipetting. When the pipette tip 14 is in a relaxed state, the inner surface 104 of the annular wall 101 is angled slightly inward as the annular wall 101 extends upward toward the opening 42 of the collar. This slight inward inclination provides a lateral interference fit between the inner surface 104 of the annular wall 101 and the cylindrical seal area 55 of the mounting shaft 12 when the mounting shaft 12 is fully inserted. The annular wall 101 extends above the peripheral shoulder 40, thereby creating a gap 106 between the annular wall 101 and the collar sidewall 36. When the pipette mounting shaft 12 is inserted into the pipette tip 14, the gap 106 allows the annular wall 101 to rotate laterally outward. The inner diameter directly below the annular wall 101 is selected to ensure zero interference with the mounting shaft 12. Rather, the lateral interference fit of the annular wall 101 of the circular cantilever seal ring 100 above the shoulder 40 of the pipette tip 14 provides a sealing engagement of the pipette tip 14 to the mounting shaft 12.

[0047] Referring to Figures 6, 9, and 10, the locking section 30 of the mounting shaft 12 has a central cylindrical alignment section 56 located directly above and adjacent to the stop 34. When the pipette tip 14 is mounted on the mounting shaft 12, the central cylindrical alignment section 56 on the mounting shaft 12 helps to hold the pipette tip 14 in a linear direction. However, preferably, when the pipette tip 14 is mounted on the mounting shaft 12, there is clearance between the collar sidewall 36 of the pipette tip 14 and the central cylindrical alignment section 56. At the stop 34, the diameter of the mounting shaft 12 decreases (e.g., forms a step) between the cylindrical section 56 at the top of the stop 34 and the sealing section 55 at the bottom of the stop 34. The decrease in shaft diameter at the stop 34 roughly corresponds to the decrease in diameter at the periphery 40 of the matching pipette tip 14. This decrease is preferably in the range of about 0.1 to 1.0 mm. The cylindrical alignment section 56 and the stop 34 do not need to be continuous at the periphery of the mounting shaft 12, because the purpose of these components is to provide a secure and stable locking engagement of the pipette tip 14 on the mounting shaft 12, not to provide a seal. In this respect, the configuration of the mounting shaft 12 in the exemplary embodiment is similar to U.S. Patents 7,662,343, 7,662,344, 8,277,757, 8501,118, 8877,513 and 9333,500, which are owned by the assignee (applicant) of this application.

[0048] At the top of the cylindrical alignment section 56, the diameter of the mounting shaft 12 can be reduced, which can provide additional clearance between the mounting shaft 12 and the collar of the pipette tip 14. Referring to Figure 6, as previously mentioned, the top of the lock section 30 of the mounting shaft 12 includes two or more lock lobes 50 evenly spaced around the mounting shaft 12, with corresponding concave areas 58 straddling between the lock lobes 50. The lobes 50 include inclined ramps 60 that slope relatively gently. A preferred slope of the inclined ramps 60 is between 10 and 20 degrees with respect to the vertical axis of the mounting shaft. The lobes 50 are angled outward as the inclined ramps 60 extend toward the peak portion 61 of the lobes 50. Furthermore, each lobe 50 includes a descending ramp 62, which slopes inward as it extends upward away from the peak portion 61. Preferably, the inward slope of the descending ramp 62 is identical to the outward slope of the inclined ramp 60, but such symmetry is not essential. Preferably, the peak portion 61 is curved, with a radius between 0.15 mm and 0.38 mm. At the peak portion 61, the lobe 50 preferably extends outward beyond the outer surface of the cylindrical alignment section 56, but the exact preferred dimensions depend on the taper amount and tip wall thickness of the tip collar 36 of the corresponding matching pipette tip. The mounting shaft 12 is preferably formed from a material that reduces rough edges and friction.

[0049] Preferably, when the mounting shaft 12 is fully inserted into the pipette tip 14, the recess 58 between the lobes 50 consumes a substantial portion of the circumference of the mounting shaft 12 at the peak portion 61, and further consumes along the ramp 62 where the lock ring 48 on the pipette tip 14 normally engages. In an exemplary embodiment of the present invention, the lobes 50 at the peak portion 61 occupy less than 15% of the circumference of the mounting shaft. The narrow lock lobes 50 reduce friction associated with mounting and discharging the pipette tip 14. Note that the recess 58 extends along the mounting shaft 12 below the height of the lobes 50 to accommodate inward distortion of the tip collar 36 when the pipette tip is mounted on the mounting shaft 12.

[0050] Referring to Figures 13a to 13c, as the mounting shaft 12 is pressed into the pipette tip 14, the first contact point is when the tip edge 110 of the mounting shaft 12 passes through the opening formed by the upper end edge 102 of the annular wall 101 of the circular cantilever seal ring 100. Referring to Figure 13a, the tip edge 110 of the mounting shaft 12 is substantially tapered to facilitate secure insertion as the tip edge 110 passes through the upper end edge 102 of the annular wall 101.

[0051] The corner between the upper edge 102 and the inner surface 104 is rounded to facilitate proper insertion. As the mounting shaft 12 continues its insertion path, the inner surface 104 of the annular wall 101 is bent outward as the diameter of the mounting shaft 12 increases. Figure 13b shows the lateral inner surface 104 engaging with the sealing region 55 of the mounting shaft 12 to form a lateral seal engagement. Preferably, the sealing region 55 on the mounting shaft 12 is cylindrical so that the lateral seal is cylindrical and perpendicular. This configuration is particularly advantageous with a cylindrical sealing region 55 on the mounting shaft 12 because the lateral cylindrical seal provides a robust seal and is provided with relatively low insertion force. In Figure 13b, the annular wall 101 and its inner surface 104 are shown as if the annular wall 101 were not theoretically bent outward as the mounting shaft 12 is inserted. Figure 13b shows the amount of interference between the inner surface 104 of the annular wall 101 and the cylindrical sealing region 55 of the mounting shaft 12. Figure 13c shows this in a similar manner.

[0052] Figure 13c shows the mounting shaft 12 fully inserted into the pipette tip 14, with the circumferential stop 34 of the mounting shaft 12 in contact with the upper edge 102 of the annular wall 101 of the circular cantilever seal ring 100 at the pipette tip 14. As previously stated, in the exemplary embodiment, the stop 34 is angled so that it contacts the corner 108 between the inner surface 104 of the annular wall 101 and the upper edge 102. The stop 34 is not intended to seal at this position and may optionally contain one or more voids around its periphery to ensure that a seal does not occur at the stop 34. Angling the stop 34 is advantageous because it can accommodate manufacturing tolerances of the mounting shaft 12 or the pipette tip 14.

[0053] Reference numeral 114 in Figure 10 indicates the threshold position where there is zero interference between the inner surface 104 of the annular wall 101 of the circular cantilever seal ring 100 positioned on the pipette tip 14 and the cylindrical seal area 55 of the mounting shaft 12. Lateral interference seal occurs at the corner 108 and at the inner surface 104 above the zero interference threshold position 114. In this exemplary embodiment, the vertical length of the interference is preferably 0.20 to 0.30 mm. The maximum interference is preferably 0.08 mm, which has been shown to provide a robust seal even when considering normal machining and forming tolerances. The annular wall 101 is bent radially outward into a gap 106 to absorb interference between the cylindrical seal area 55 of the mounting shaft 12 and the inner surface 104 of the annular wall 101. In this exemplary embodiment, the height of the gap 106 is 0.30 mm and the maximum width is 0.30 mm.

[0054] The diameter of the mounting shaft 12 tapers slightly between the cylindrical seal region 55 and the sharply tapered tip edge 110. At the same time, the inner diameter of the pipette tip 14 below the zero-interference threshold 114 continues to slightly expand to ensure clearance below the threshold 114 and very little friction. Referring to Figure 13c, just above the sharply tapered tip edge 110, the mounting shaft 12 abuts against a stabilizing ring 112 located at the upper end of the barrel 38 of the pipette tip 14. The stabilizing ring 112 aligns the pipette tip 14 with the mounting shaft 12, thereby eliminating the need for the circular cantilever seal ring 100 to align the pipette tip 14. This improves the interference fit symmetry in the lateral seal 104 (inner surface 104) and the alignment of the tip opening 44 (Figure 2). The structural model of the chip (Figure 17) showed that removing the stabilizing ring 112 increased the force on the seal ring 100 by 72%, increasing the risk of fluid leakage (e.g., during touch-off). This result was empirically confirmed experimentally. The experiments showed that when lateral displacement was applied, the chip without the stabilizing ring 112 consistently leaked, whereas the chip with the stabilizing ring did not leak when the same lateral displacement was applied.

[0055] Referring to Figures 9 and 10, as the mounting shaft 12 is inserted into the pipette tip 14, the inclined ramp 60 of the lock lobe 50 begins to engage with the top of the tip collar 36 just before the circumferential stop 34 on the mounting shaft 12 contacts the upper edge 102 of the annular wall 101 of the circular cantilever seal ring 100 on the pipette tip 14. As the mounting shaft 12 is further inserted into the tip, the inclined ramp 60 on the lobe 50 presses against the lock ring 48 on the tip collar 36, gently bending and deforming the tip collar 36 into a non-circular shape. The concave region 58 on the mounting shaft 12 provides ample clearance for the straightening of the tip collar 36 that occurs between the lobes 50. The intention is for the lobes 50 on the mounting shaft 12 to deform the tip collar 36 into a non-circular shape, not to stretch it. Referring to Figure 10, when the mounting shaft 12 is fully inserted into the tip collar 36 of the pipette tip, the stop 34 on the mounting shaft 12 abuts against the corner 108 of the annular wall 101 of the circular cantilever seal ring 100 on the pipette tip 14, preventing the shaft 12 from moving further into the pipette tip 14. At the engagement point, the locking ring 48 on the inner surface of the tip collar 36 slides almost simultaneously (more or less) over the peak 61 of the lobe 50 on the mounting shaft 12, thereby engaging with the portion of the descending ramp 62 of the lobe 50. This securely locks the pipette tip 14 in place on the mounting shaft 12, with a secure engagement on the one hand between the stop 34 on the mounting shaft 12 and the corner 108 of the annular wall 101 on the pipette tip 14, and a secure engagement on the other hand between the portion of the descending ramp 62 of the lobe 50 on the mounting shaft 12 and the bottom surface of the locking ring 48 on the tip collar 36. As mentioned above, the stabilizing ring 112 on the top of the tip barrel 38 aligns the pipette tip 14 with the bottom of the circular cantilever seal ring 100. Meanwhile, the interaction between the lobe 50 on the mounting shaft 12 and the locking ring 48 of the tip collar 36 provides alignment with the top of the circular cantilever seal ring 100.

[0056] Figure 11 shows a cross-sectional view of the tip collar 36, which covers the lobe 50 and is locked to the mounting shaft 12, as seen from above. The tip collar 36 is bent and distorted into a non-circular shape. Note that the dashed line 70 indicates the relaxed, rounded state of the outer surface of the collar's opening before it is mounted on the mounting shaft 12. The dashed line 72 indicates the position of the inner surface of the lock ring 48 on the tip collar 36 in its relaxed, rounded state before it is mounted on the mounting shaft 12, covering the lobe 50. Even when the mounted tip collar 36 is bent and distorted and deviates from its circular shape, the structural strength of the peripheral shoulder 40 maintains the circular shape between the peripheral shoulder 40 and the circular cantilever seal ring 100.

[0057] To attach the pipette tip 14, instead of stretching the tip collar 36, bending or deforming the tip collar 36 reduces the required insertion force compared to tip mounting configurations that require a tight interference fit or stretching of the tip collar. Furthermore, as described above, when providing a lateral interference fit seal, bending the annular wall 101 of the circular cantilever seal ring 100 further reduces the required insertion force compared to stretching the tip or crushing the annular seal of the pipette tip. Nevertheless, the user receives reliable tactile feedback that full engagement is complete when the stop 34 engages with the circular cantilever seal ring 100 on the pipette tip 14, the lock ring 48 on the pipette tip 14 slides over the lobe 50, and the mounting shaft 12 abuts against the stabilizing ring 112. The lock engagement is robust and prevents unintended tip detachment when lateral forces are applied to the tip, for example, during a touch-off procedure. The seal is also robust even with low insertion force.

[0058] Another advantage of the present invention is the even lower discharge force. Referring to Figure 12, a structure is shown in which the stripping plate 23 moves downward (arrow 23a) to push the top of the tip collar 36 and discharge the pipette tip 14. This is common in the background art. When the locking ring 48 clears the peak 61 in the lobe 50, the energy accumulated in the distorted tip collar 36 is released, facilitating the efficient discharge of the pipette tip 14 from the mounting shaft 12. By using a lobe 50 having a gently sloping descending ramp 62 and a curved peak 61 connecting the inclined ramp 60 to the descending ramp 62, sufficient lateral stability is ensured while reducing the required discharge force. Furthermore, the configuration (i.e., the use of stop 34) prevents the mounting shaft 12 from being excessively inserted into the pipette tip 14, so the required discharge force is constant and does not depend on the depth of insertion of the mounting shaft 12, as in some pipette tips of the background art. Furthermore, the force required to release the pipette tip 14 from the circular cantilever seal ring 100 is smaller than that required for the annular seal rings of the background technology, which rely on stretching the tip or crushing the seal ring.

[0059] Disposable pipette tips 14 are typically manufactured by injection molding of virgin polypropylene. Figure 14 shows a partial cross-section of a polypropylene pipette tip 14 molded in accordance with exemplary embodiments of the present invention described in Figures 1 to 13. Figure 14 shows a cross-section of a circular cantilever seal ring 100 and a stabilizing ring 112. This pipette tip is for a 125 μl fitting. The minimum diameter of the inner surface 104 of the annular wall 101 of the circular cantilever seal ring 100 is 2.58 mm ± molding tolerance. The height of the gap 106 around the annular wall 101 is 0.30 mm ± molding tolerance. The inner diameter of the stabilizing ring 112 is 2.58 mm ± molding tolerance. Figure 15 shows comparative data, which compares the insertion force of a tip manufactured according to the present invention and created based on the photograph in Figure 14 to the insertion force of a tip manufactured according to the applicant's prior design and sealed using a seal ring within the tip barrel. The data in Figure 15 shows that the maximum force required to insert the mounting shaft 12 into a pipette tip 14 manufactured according to the present invention is significantly less than the maximum force required to insert the mounting shaft 12 into a pipette tip 14 manufactured according to the applicant's prior design for a similar size (125 μl). The y-axis in Figure 15 plots the insertion force as a percentage of the maximum insertion force of the prior design. The x-axis plots the insertion distance as a percentage of the end of the insertion process. In both cases, the insertion force shows a localized peak as the locking ring 48 in the pipette tip 14 is distorted when the inclined ramp 60 of the lobe 50 in the mounting shaft 12 is pressed against the locking ring 48. The localized maximum value in the tip constructed according to the present invention is about 50%, compared to about 89% in the applicant's prior design. As the mounting shaft 12 is further inserted, the insertion force decreases slightly as the peak of the lobe 50 clears the locking ring 48 in the tip collar. Subsequently, the insertion force in both devices shows a slight upward trend, continuing until the stop 34 on the mounting shaft 12 reaches the end of its range of motion.The applicant's previous chips required approximately 100% insertion force at the end of the insertion process, whereas the chip configured according to the present invention requires approximately 58% insertion force at the end of the insertion process. The reduction in insertion force is due to the use of a circular cantilever seal ring 100 instead of a seal ring inside the barrel, which would otherwise require the barrel to be stretched or the seal ring to be crushed.

[0060] The data in Figure 15 pertains to a 125 μl pipette tip, but the present invention is also applicable to pipette tips with different sizes of collars. For larger tip collars, it may be desirable to modify the configuration to incorporate an O-ring 120 into the sealing area 155 of the mounting shaft 113, as shown in Figure 16. The configuration of the circular cantilever seal ring 100 remains conceptually unchanged, but the O-ring 120 is positioned to engage with the inner surface of the annular wall 101 rather than the cylindrical portion of the mounting shaft 113. Although the mounting shaft 113 with the O-ring 120 is capable of effective operation, the present invention is intended to significantly reduce insertion force and eliminate the need for the O-ring 120 in most practical situations.

[0061] Figure 18 shows a pipette tip rack system 20, which is configured to withstand harsh operating conditions in a robotic liquid handling system configured according to an exemplary first embodiment of the present invention. The pipette tip rack system 20 comprises a reusable base 200 and a refill pack 202, the refill pack 202 containing an array of 384 pipette tips 14. In Figure 18, the refill pack 202 is set in the reusable base 200 with the transparent cover 204 attached. Figure 19 is an assembly diagram illustrating the components of the refill pack 202, which includes a disposable tip receiver or liner 206, a removable vertical support rib 208, a plastic tip insert 212, an array of 384 pipette tips 14, and a transparent cover 204. Furthermore, Figure 19 shows the reusable base 200.

[0062] The disposable tip receiver 206 defines wells for housing the barrel portions of pipette tips 14 and has two vertical rib mounts 210 that vertically hold vertical support ribs 208, thereby supporting plastic tip inserts 212. When an array of 384 pipette tips 14 is simultaneously mounted on an array of mounting shafts in a pipette head, the support by the vertical support ribs 208 is provided to hold the plastic tip inserts 212 in a planar position. The plastic tip inserts 212 are positioned across the wells of the disposable tip receiver 206. The peripheral skirt of the plastic tip inserts 212 is supported by the receiver sidewalls of the disposable tip receiver 206 for packaging purposes. The array of 384 holes in the plastic tip inserts 212 holds the array of pipette tips 14 such that the centerlines of each hole are spaced 4.5 mm apart from one another, in accordance with the SBS industry standard. The pipette tips 14 are held nearly vertically with the collar of each pipette tip facing upward. This facilitates the attachment of pipette tips to an array of pipette mounting shafts 12 in a robotic liquid handling system, such as system 10. However, the pipette tips 14 may also be used with handheld pipettes. The transparent cover 204 covers the plastic tip insert 212 and the collar of the pipette tip 14, which is held in position by the plastic tip insert 212, for packaging, transport, and storage purposes. Using the cover 204 in combination with the disposable tip receiver 206 and the plastic tip insert 212 is an effective and convenient method for packaging sterile pipette tips, although the cover 204 may also be used with non-sterile pipette tips.

[0063] After attaching the pipette tip 14, the plastic tip insert 212 may be removed from the disposable tip receiver 206, and the vertical support rib 208 may also be removable from the vertical rib mount 210 inside the disposable tip receiver 206. The plastic tip insert 212 is configured to be stackable, and the disposable tip receiver 206 is configured to be nestable, thereby reducing the need for waste storage in the laboratory.

[0064] Referring to Figure 20, the reusable base 200 includes a bottom wall 222, side walls 218, 220, a front wall 214, and a back wall 216. Figure 20 shows the reusable base 200 with a refill pack 202 set inside. The upper parts of the base side walls 214, 216, 218, 220 of the reusable base 200 support the peripheral skirt 224 of the plastic tip insert 212, providing primary support when the pipette tip 14 is attached to the mounting shaft 12 of the array pipette. Furthermore, the bottom wall 222 of the base supports a vertical support rib 208 (hidden in Figure 20) within the well of the disposable tip receiver 206. This supports the central part of the bottom of the plastic tip insert 212 when the pipette tip 14 is attached to the mounting shaft 12 of the array pipette. The disposable tip receiver 206 has a bottom wall 226, side walls 228, 230, a front wall 232, and a rear wall 234. It also has a peripheral rim 236 extending laterally from the upper rim of the receiver side walls 228, 230, 232, 234. The dimensions of the disposable tip receiver 206 are selected such that the bottom wall 226 of the disposable tip receiver 206 lies on the bottom wall 222 of the reusable base 200 when it is inserted into the reusable base 200. Finger notches 264 in the front wall 214 and rear wall 216 of the reusable base 200 facilitate the removal of the refill pack 202 from the reusable base 200 after use.

[0065] Referring to Figures 21 to 23, the chip receiver 206, also called the liner, is preferably formed from injection-molded clear polypropylene. Each support rib mount 210 includes a low wall 210a and a high wall 210b. The stepped height facilitates the mounting of the vertical support ribs 208. The low wall 210a and the high wall 210b extend upward from the bottom wall 226 and inward from the adjacent side walls 232 and 234, respectively. The low wall 210a and the high wall 210b are spaced to form mounting slots for the vertical support ribs 208. Furthermore, each of the low wall 210a and the high wall 210b has a vertical recess that receives each vertical ridge in the removable vertical support rib 208. The interaction between the vertical recess and the vertical ridge in the vertical support rib 208 helps stabilize the vertical support rib 208, especially when the rib 208 is subjected to the full load. The inner edges of the low wall 210a and the high wall 210b are inclined.

[0066] The side walls 228, 230, 232, and 234 of the chip receiver are angled outward, for example, at about 5 degrees, as they extend upward from the bottom wall 226. Each of the side walls 228, 230 includes a vertical stacking rib 238 (vertical nesting ridge 238), which facilitates the proper nesting of the used chip receiver 206 after use and assists in the alignment of the replenishment pack 202 as it is set in the reusable base 200. In this embodiment, the vertical stacking rib 238 extends downward from the peripheral rim 236 along each side wall 228, 230 to about half the height of the chip receiver 206. The peripheral rim 236 on the chip receiver 206 is wider at the top of the side walls 228, 230 than at the top of the front wall 232 and the back wall 234. The peripheral rim 236 includes two snap-fit ​​holes 240 on each side and two slots 242 on each side for guide posts. The snap-fit ​​holes 240 are snap-fitted to the snap fittings of the plastic tip insert 212 and are configured to hold the tip receiver 206 together with the refill pack 202 during transport, storage, and use. However, the snap connections can be relatively easily disassembled by a laboratory worker if the packaging is disassembled for storage after use of the refill pack before disposal or recycling.

[0067] Referring to Figures 24 to 26, preferably, the plastic tip insert 212 is formed from injection-molded polypropylene, which is color-coded to represent the size and configuration of the mounting shaft 12. This is configured to accommodate the pipette tip 14. The plastic tip insert 212 shown in Figures 24 to 26 has an array of 384 holes, which hold the pipette tip 14. These are arranged in 16 rows, designated A to P, and 24 columns, designated 1 to 24, according to industry standards. The spacing between the centerlines is 4.5 mm, which is also an industry standard and conforms to the SBS standard. Referring particularly to Figure 25, four snap fittings 244 and four guide posts 246 extend from the bottom of the plastic tip insert 212. The snap fittings 244 are formed with vertical slots, which allow the sides of the fittings to press together. Furthermore, the snap fitting 244 has a groove into which the peripheral rim 236 of the tip receiver 206 is fitted when the plastic tip insert 212 is connected to the tip receiver 206. The snap fitting 244 passes through snap-fit ​​holes 240 located in the peripheral rims 236 on both the left and right sides of the tip receiver 206. The snap-fit ​​is strong enough to maintain the connection during transport, storage, and use, but the fit of the snap fitting 244 and the holes 240 in the tip receiver 206 is chosen to allow the plastic tip insert 212 to be removed from the tip receiver 240 relatively easily after use. The guide post 246 is positioned closer to the corner of the plastic tip insert 212 than the snap fitting 244 and is longer than the snap fitting 244. The guide post 246 has a tapered end and is intended to be inserted into a guide hole in the reusable base 200. The slot 242 in the peripheral rim 236 of the tip receiver 206 provides clearance for the guide post 246 but does not interfere with disassembling the plastic tip insert 212 from the tip receiver 206.The purpose of the guidepost 246 is to accurately position the plastic tip insert 212 and the pipette tip 14 when the refill pack 202 is set in the reusable base 200. The outer skirt 224 (peripheral skirt 224) surrounding the plastic tip insert 212 is configured to be positioned on the upper part of the base sidewall of the reusable base 200 when the refill pack 202 is placed in the reusable base 200. Furthermore, the plastic tip insert 212 is configured to be stackable after being disassembled from the tip receiver 206. The elongation recesses 248 along each side of the plastic tip insert 212 provide clearance between the guidepost 246 and the snap fitting 244 when the plastic tip inserts 212 are stacked, and the guidepost 246 located at the ends of the elongation recesses 248 contributes to the stabilization of the stack.

[0068] Figure 27 shows a refill pack 202 being inserted into a reusable base 200, specifically the upper part of one of the side walls 218. The upper parts of the side walls 218 on both sides include guide holes 250 for guide posts 246 extending downward from the plastic tip insert, vertical slots 252 for vertical stacking ribs 238 in the tip receiver 206, and snap-fit ​​holes 254 for snap fittings 244 that attach the tip receiver 206 to the plastic tip insert 212. Preferably, the guide holes 250 have enlarged tapered openings to assist in the alignment of the guide posts and the refill pack 202 as it is set in the reusable base 200. The vertical ribs 238 are first set in the slots 252, which are wide enough to facilitate initial alignment during insertion. Subsequently, the guide post 246, having a tapered end, is inserted into the guide hole 250, which has a tapered opening, guiding the refill pack 202 to the precise x / y position relative to the reusable base 200. The opening 254 provides clearance for the snap fitting 244. When the pipette tips 14 are loaded, the guide post 246 is subjected to a lateral force, holding the plastic tip insert 212 aligned with the reusable base 200. Figure 28 shows the refill pack 202, which is set in the reusable base 200 with the cover 204 removed to expose the pipette tips 14 for loading into the array on the mounting shaft 12. The dimensions of the outer skirt 256 (bottom peripheral wall 256) of the reusable base 200 are configured to match the dimensions of the nest 21 of the liquid handling device, for example, preferably the SBS dimensions, so that the array of pipette tips 14 can be precisely positioned according to the SBS standard and ready for loading.

[0069] Figure 29 shows the refill pack 202 and reusable base 200 after the tips have been loaded. Figure 30 is a cross-sectional view showing how the plastic tip insert 212 is supported while the tips are being loaded. The refill pack 202 is placed on the reusable base 200, so that the base sidewalls 214, 216, 218, 220 (see Figure 20) of the reusable base 200 support the peripheral skirt 224 of the plastic tip insert 212 when the pipette tips 14 are attached to the array on the pipette mounting shaft. The base sidewalls 214, 216, 218, 220 of the reusable base are configured to withstand the cumulative load of 384 tips and have an outer wall 258 and an inner wall 260 connected to a planar edge 262 at the top, as shown in Figure 30. Preferably, the reusable base 200 is molded from opaque polycarbonate. The bottom wall 226 of the reusable base 200 supports the vertical support rib 208 and further supports the bottom surface of the plastic tip insert 212.

[0070] The vertical support rib 208 prevents the plastic tip insert 212 from bending due to cumulative load pressure. Preferably, the rib is positioned equidistant from the side walls of the tip receptacles 228, 230, and further equidistant between the side walls 218, 220 of the reusable base 200 when the replenishment pack 202 is set on the base 200. The vertical support rib 208 is positioned within the well of the tip receptacle 206 and is detachably mounted on a vertical rib mount 210 located within the well of the tip receptacle 206. The vertical support rib 208 extends vertically from the bottom wall 226 of the tip receptacle 206 to the bottom surface of the plastic tip insert 212. The bottom wall 226 of the tip receptacle 206 is positioned within the bottom wall 222 of the reusable base 200, and the bottom wall of the reusable base 200 is positioned within the nested surface of the liquid processing apparatus. Therefore, the vertical support rib 208 should provide consistent support, unless the load is so excessive that it cannot deform or tilt the vertical support rib 208. As shown in Figure 30 and other figures, the vertical support rib 208 has reinforcing ridges 266, 268. The vertical reinforcing ridges 268 extend outward from the vertical support rib 208 than the horizontal reinforcing ridges 266 and are positioned so as not to interfere with the placement of the pipette tip in the SBS configuration. Some of the vertical reinforcing ridges 268 fit into recesses in the rib mount 210, helping to fix the position of the vertical support rib 208 within the tip receiver 206.

[0071] Figures 31 and 32 show a refill pack 202 disassembled after use. In Figure 31, the plastic tip insert 212 is removed from the tip receptacle 206 by separating the snap fitting 244 from the tip receptacle 206. Figure 31 shows the vertical support rib 208 removed from the mount 210 in the well of the tip receptacle 206. After being removed from the mount, the vertical support rib 208 can be laid flat in the well of the tip receptacle 206, facilitating stacking and nesting of used tip receptacles.

[0072] Figure 33 shows a stack of nested chip receivers 206 compared to a stack of chip racks, a background technology used in automated liquid handling applications. The disassembled, disposable chip receivers 206 save significant space during storage before disposal or recycling. Figure 34 shows a cross-sectional view of the stack of chip receivers 206, and in particular shows the stacking ribs 238 that support the chip receivers 206 with a peripheral rim 236 of the chip receivers 206 stacked on top of them. The stacking ribs 238 ensure that the mount does not interfere with forming a stable stack.

[0073] Figures 35 to 45 show a pipette tip rack system 301, a robotic liquid handling system constructed according to an exemplary second embodiment of the present invention, configured to withstand harsh conditions. The pipette tip rack system 301 is similar in many ways to those described in Figures 18 to 34, except that it is configured to hold 96 pipette tips instead of 384, and is taller to accommodate longer pipette tips 14 than those shown in relation to Figures 18 to 34. The following description will focus on the differences between the two embodiments.

[0074] Referring to Figure 35, the pipette tip rack system 301 has a two-part reusable base 300. The lower portion 300a is substantially identical to the base 200 of the previous embodiment. The upper portion 300b of the reusable base 300 is superimposed on the lower portion 300a, as shown in the figure. This two-part configuration allows the lower portion 300a to be used for lower refill packs 202, or, when that portion is used, for higher refill packs 302. The reusable base 300 does not need to be two-part to carry out other embodiments of the invention.

[0075] Figure 36 shows the disassembled parts of the tip rack system 301, similar to Figure 19 which shows the lower tip rack system 20. This system is similar to the one described in Figure 19, except that the plastic tip inserts are for 96 tips and the reusable bases 300a, 300b include two parts, with the exception that the tip receiver 306 and vertical support ribs 308 are taller. Preferably, the transparent cover 304 is the same as the transparent cover 204 in the embodiment described in relation to Figure 19. Figures 37 to 39 show the taller tip receiver 306. This is similar to the previous embodiment 206 (tip receiver 206), but with an increased overall height, an increased height for the mount 210, and longer stacking ribs 338 (nested ridges 338). Figures 40 and 41 show a 96-hole plastic tip insert 312 with 8 rows (AH) and 12 columns (1-12) of holes for holding pipette tips 14. Other features of the plastic tip insert 312 shown in Figures 40 and 41 are similar to those of the previous embodiment, including the guide post 346 and snap fitting 344.

[0076] Figure 42 is a cross-sectional view showing the load-bearing components within the tall chip rack system 301. The plastic chip insert 312 is supported in a manner similar to that described in the low chip rack system 20.

[0077] Figure 43 shows a stack of tall tip receptacles 306 compared to a stack of tall tip receptacles racks, a background technology used in automated liquid processing applications. Disassembled disposable tip receptacles 306 save considerable space during storage before disposal or recycling. Figure 44 shows a cross-sectional view of a stack of tall tip receptacles 306, specifically showing the stacking ribs 338, which support the stacked tip receptacles 306 with their peripheral rims 336. The stacking ribs 338 ensure that the mounts 310 do not interfere with the stable stack.

[0078] While exemplary embodiments of the present invention have been described in conjunction with the drawings, those skilled in the art will understand that various aspects and features of the present invention may be implemented in other forms.

Claims

1. A pipette tip rack system for a robotic liquid handling system, comprising a reusable base and a refill pack for housing an array of pipette tips, The aforementioned refill pack is A tip receiver having a bottom wall, side walls, a front wall, and a back wall, defining a well for housing the barrel portion of a pipette tip, and having one or more vertical rib mounts, A plastic tip insert is positioned across the well and has a peripheral skirt, the peripheral skirt being supported by the side wall, the front wall and the back wall of the tip receiver for packaging purposes, the plastic tip insert having an array of holes for holding an array of pipette tips, the centerlines of each hole spaced 4.5 mm or 9 mm apart from each other, so that the pipette tips are held substantially vertically, the collar of each pipette tip is positioned upward, facilitating the attachment of pipette tips to the array of pipette mounting shafts in the robotic liquid handling system, and the plastic tip insert is removably attached to the tip receiver, A removable cover that covers the plastic tip insert and the collar of the pipette tip held in position by the plastic tip insert, A vertical support rib set on one or more of the vertical rib mounts, extending upward from the bottom wall of the chip receiver to the bottom surface of the plastic chip insert, and including a vertical support rib that is removable from one or more of the vertical rib mounts and the chip receiver. The reusable base includes a bottom wall, side walls, a front wall, and a back wall, and the refill pack is set inside the reusable base. As a result, when a pipette tip is attached to the mounting shaft of the array pipette in the robotic liquid handling system, the side wall, front wall, and back wall of the reusable base support the peripheral skirt of the plastic tip insert. When a pipette tip is attached to the mounting shaft of the array pipette in the robotic liquid handling system, the bottom wall of the reusable base supports the vertical support rib and the bottom surface of the plastic tip insert. Pipette tip rack system.

2. The chip receiver includes two vertical rib mounts, one of which is a vertical rib mount integrated with the bottom wall and the front wall, and the other is a vertical rib mount integrated with the bottom wall and the rear wall. The pipette tip rack system for a robotic liquid handling system according to claim 1, wherein the vertical rib mount is positioned and configured to hold the vertical support rib at an equidistant distance from the side wall of the tip receiver.

3. The chip receiver has a horizontal peripheral rim extending outward from the top of the side wall, the front wall, and the back wall, the peripheral rim including at least one snap-fit ​​hole, the at least one snap-fit ​​hole adjacent to each side wall for snap-fitting with the plastic chip insert, The side walls of the reusable base further have at least one snap-fit ​​hole, the at least one of which is located at the top of each side wall for snap-fitting with the plastic tip insert. The plastic chip insert has at least one snap fitting extending downward from the peripheral skirt, the at least one snap fitting extending through each snap-fit ​​hole in the peripheral rim of the chip receiver, and extending into the snap-fit ​​holes in the side wall of the reusable base when the chip receiver is loaded into the reusable base, The snap fitting of the plastic tip insert is removable from the reusable base and the tip receiver after use, and the plastic tip insert is disassembled from the reusable base and the tip receiver, a pipette tip rack system for a robotic liquid handling system according to claim 1.

4. The plastic tip insert further includes a guide post, the guide post extending downward from the peripheral skirt, The peripheral rim of the chip receiver includes holes or slots through which the guide posts pass. The pipette tip rack system for a robotic liquid handling system according to claim 3, wherein the side wall of the reusable base includes guide holes, the guide holes are located at the top of each side wall relative to each guide post.

5. The plastic chip insert is removable from the chip receiver after use, and the plastic chip insert is stackable when removed from the chip receiver. The vertical support rib is detachable from the vertical rib mount within the chip receiver. A pipette tip rack system for a robotic liquid handling system according to claim 1, wherein the tip receivers are stackable when disassembled from the plastic tip insert and the vertical support ribs are disassembled from the vertical rib mount.

6. The outer surfaces of the opposing walls of the chip receiver have vertical nesting ridges, and these vertical nesting ridges extend partially downward from the peripheral rim to each wall. The reusable base has slots for vertically nested ridges, pipette tip rack system for a robotic liquid handling system according to claim 1.

7. A pipette tip rack system for a robotic liquid handling system according to claim 2, wherein each vertical support rib includes a pair of vertical walls.

8. The pipette tip rack system for a robotic liquid handling system according to claim 2, wherein the vertical support ribs include vertical ridges and horizontal ridges, and each vertical rib mount is configured to receive at least one of the vertical ridges.

9. The pipette tip rack system for a robotic liquid handling system according to claim 1, wherein the bottom peripheral wall of the reusable base has nested outer dimensions conforming to the SBS standard.

10. A refill pack containing an array of disposable pipette tips, A tip receiver having a bottom wall, side walls, a front wall, and a back wall, defining a well for housing the barrel portion of a pipette tip, and having one or more vertical rib mounts, A plastic tip insert is positioned across the well and has a peripheral skirt, the peripheral skirt being supported by the side wall, the front wall, and the back wall of the tip receiver for packaging purposes, the plastic tip insert having an array of holes for holding an array of pipette tips, the centerlines of each hole spaced 4.5 mm or 9 mm apart from each other, so that the pipette tips are held substantially vertically, the collar of each pipette tip is positioned upward, facilitating the attachment of pipette tips to an array of pipette mounting shafts in a robotic liquid handling system, and the plastic tip insert is removably attached to the tip receiver, A removable cover that covers the plastic tip insert and the collar of the pipette tip held in position by the plastic tip insert, A vertical support rib set on one or more of the vertical rib mounts, extending upward from the bottom wall of the chip receiver to the bottom surface of the plastic chip insert, and a vertical support rib that is removable from one or more of the vertical rib mounts and the chip receiver, The system comprises an array of 96 or 384 disposable pipette tips housed within the aforementioned plastic tip insert. Refill pack.

11. A refill pack comprising an array of disposable pipette tips according to claim 10, wherein the array of disposable pipette tips comprises 384 disposable pipette tips, and the load force of each pipette tip is less than 8 Newtons.

12. A refill pack comprising an array of disposable pipette tips according to claim 10, wherein the array of disposable pipette tips comprises 96 disposable pipette tips, and the load force of each pipette tip is less than 10 Newtons.

13. The disposable pipette tips are configured for use in the robotic liquid handling system having an array of pipette tip mounting shafts; each pipette tip mounting shaft includes an upper locking section with a stop, and a plurality of outwardly projecting lobes, positioned above the stop and spaced circumferentially around the locking section of the mounting shaft, and recessed relief portions positioned circumferentially between the lobes and recessed relative to the lobes; each lobe has a peak spaced longitudinally at a predetermined distance from the stop on the mounting shaft; each tip mounting shaft includes a sealing region located below the stop on each tip mounting shaft; Each disposable pipette tip also: A barrel having a lower opening for drawing liquid into the barrel and discharging the liquid from the barrel, wherein the diameter of the lower opening is smaller than the diameter of the barrel at the upper end of the barrel, A collar having a continuous inner surface with a circumference in a relaxed state, an upper opening for receiving a tip mounting shaft, and a lower end having an inner diameter larger than the inner diameter of the upper end of the barrel, The lower end of the collar is connected to the upper end of the barrel by the peripheral shoulder portion of the tip, A circular cantilever seal ring having an annular wall extending from the peripheral shoulder of the tip toward the opening of the collar, and including a circular cantilever seal ring that laterally engages with and seals the sealing area of ​​the mounting shaft when the tip is fully mounted on the mounting shaft, The annular wall has an upper edge, and the upper edge abuts against the stop on the mounting shaft when the tip is fully mounted on the mounting shaft. When the pipette tip is attached to the tip mounting shaft, the collar of the disposable pipette tip has sufficient flexibility to deform outward at the lobes on the mounting shaft and inward at the concave relief portion on the mounting shaft between the lobes. A refill pack comprising an array of disposable pipette tips according to claim 10, wherein the peripheral shoulder has sufficient structural strength to maintain sufficient roundness of the circular cantilever seal ring so that the annular wall seals laterally with respect to the seal area of ​​the mounting shaft.

14. Each disposable pipette tip further includes an engagement means, A refill pack comprising an array of disposable pipette tips according to claim 13, wherein when the disposable pipette tips are attached to the mounting shaft of the tips and the annular wall engages with the stop on the mounting shaft, the collar deforms outward at the lobe and inward at the concave relief portion, after which the engaging means engages with each lock lobe on the mounting shaft.

15. The engaging means that engages with the pipette surface at each lock lobe includes a lock ring, A refill pack comprising an array of disposable pipette tips according to claim 14, wherein the lock ring extends inward from the continuous inner surface of the collar, surrounds the entire circumference of the collar, or substantially surrounds the entire circumference of the collar, is positioned on the rim of the upper opening of the collar, and is positioned above the peripheral shoulder at a distance corresponding to the longitudinal distance between the stop on the mounting shaft and the peak of each lock lobe on the mounting shaft.

16. A refill pack comprising an array of disposable pipette tips according to claim 13, wherein the peripheral shoulder portion of each disposable pipette tip reduces the internal bore diameter of the pipette tip by 0.1 to 1.0 mm.

17. A refill pack comprising an array of disposable pipette tips according to claim 13, wherein the inner surface of the annular wall of each disposable pipette tip inclins inward in a relaxed state as it extends from the peripheral shoulder toward the opening in the collar.

18. A refill pack comprising an array of disposable pipette tips according to claim 17, wherein the inner surface of the annular wall of each disposable pipette tip forms an interference of 0.05 mm to 0.11 mm with the cylindrical sealing area on the mounting shaft.

19. A refill pack comprising an array of disposable pipette tips according to claim 13, wherein the inclination of the inner surface of each disposable pipette tip extends downward to a threshold position for a zero interference position and continues as the inner surface extends beyond the threshold position, providing a wide clearance between the inner surface of the pipette tip and the mounting shaft below the threshold position.

20. A refill pack comprising an array of disposable pipette tips according to claim 19, wherein each disposable pipette tip further includes a stabilizing ring, the stabilizing ring being positioned on the upper portion of the tip barrel extending inward from the inner surface of the tip barrel.

21. A refill pack comprising an array of disposable pipette tips according to claim 13, wherein each disposable pipette tip further includes a stabilizing ring, the stabilizing ring being positioned on the upper portion of the tip barrel.

22. A refill pack comprising an array of disposable pipette tips according to claim 13, wherein the circular cantilever seal ring in each disposable pipette tip further includes a circumferential gap, the circumferential gap being located between the annular wall of the circular cantilever seal ring and the tip collar, above the peripheral shoulder.

23. A refill pack comprising an array of disposable pipette tips according to claim 13, wherein the height of the circumferential gap in each disposable pipette tip is in the range of 0.28 mm to 0.38 mm.

24. A refill pack comprising an array of disposable pipette tips according to claim 13, wherein each disposable pipette tip has engaging means that engage with each lock lobe on the mounting shaft, the engaging means comprising a circumferential lock ring, the circumferential lock ring being located at or near the opening of the collar of each disposable pipette tip.

25. A refill pack comprising an array of disposable pipette tips according to claim 24, wherein the circumferential locking ring in each disposable pipette tip includes a cavity.

26. A refill pack comprising an array of disposable pipette tips according to claim 10, wherein each disposable pipette tip is formed from molded polypropylene.

27. A refill pack comprising an array of disposable pipette tips; the disposable pipette tips are configured for use in a robotic liquid handling system having an array of pipette tip mounting shafts; each pipette tip mounting shaft comprises an upper locking section with a stop, and a plurality of outwardly projecting lobes, positioned above the stop and circumferentially spaced around the locking section of the mounting shaft, and recessed relief portions positioned circumferentially between the lobes and recessed relative to the lobes; each lobe has a peak longitudinally spaced at a predetermined distance from the stop on the mounting shaft; each tip mounting shaft comprises a sealing region located below the stop on each tip mounting shaft; the refill pack comprises, Each disposable pipette tip also: A barrel having a lower opening for drawing liquid into the barrel and discharging the liquid from the barrel, wherein the diameter of the lower opening is smaller than the diameter of the barrel at the upper end of the barrel, A collar having a continuous inner surface with a circumference in a relaxed state, an upper opening for receiving a tip mounting shaft, and a lower end having an inner diameter larger than the inner diameter of the upper end of the barrel, The lower end of the collar is connected to the upper end of the barrel by the peripheral shoulder portion of the tip, A circular cantilever seal ring having an annular wall extending from the peripheral shoulder of the tip toward the opening of the collar, and including a circular cantilever seal ring that laterally engages with and seals the sealing area of ​​the mounting shaft when the tip is fully mounted on the mounting shaft, The annular wall has an upper edge, and the upper edge abuts against the stop on the mounting shaft when the tip is fully mounted on the mounting shaft. When the pipette tip is attached to the tip mounting shaft, the collar of the disposable pipette tip has sufficient flexibility to deform outward at the lobes on the mounting shaft and inward at the concave relief portion on the mounting shaft between the lobes. The peripheral shoulder portion has sufficient structural strength to maintain sufficient roundness of the circular cantilever seal ring so that the annular wall seals laterally with respect to the sealing area of ​​the mounting shaft. Refill pack.

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