This patent application claims priority of the Swiss patent application No. CH 02127/13 filed on 20 Dec. 2013, the entire disclosure of which is herein incorporated by explicit reference for any purpose.
The invention relates to spacers for pipette tip carriers stacked one on top of another. In chemical, biological, pharmaceutical, and similar laboratories, small liquid volumes are typically received and discharged using pipettes. Automated liquid handling platforms are frequently used for this purpose, which enable the simultaneous receiving and/or discharging of liquid volumes with high precision and, nonetheless, high throughput rates. Such liquid handling platforms very often comprise pipetting robots, which are equipped with disposable or single-use pipette tips to avoid contaminations of a sample. Liquid handling platforms are typically charged with such disposable or single-use pipette tips, in that carrier plates equipped with pipette tips or even stacks of such carrier plates are provided. Such carrier plates typically comprise an array of pipette tips, which are arranged so that a pipetting head of a pipetting robot can receive one or more of these pipette tips. Multichannel pipetting heads can comprise one or more rows of pipettes or an array of pipettes. The pipettes of pipetting heads having many channels are preferably arranged or at least can be arranged so that rows or columns of wells of standard microplates can be processed simultaneously; multichannel pipetting heads are also known, using which all wells of a standard microplate can be processed simultaneously.
Normalized standard microplates (cf., for example, norm ANSI_SBS 1-4 2004; American National Standards Institute, 2006) are known and have arrays of wells, which are arranged, for example, at an axial spacing of 9 mm (96-well microplate) or of 4.5 mm (384-well microplate).
Carriers or carrier plates for disposable or single-use pipette tips and stacks of such carrier plates having inserted pipette tips are known from the prior art. Thus, document EP 2 210 668 A2 discloses a carrier (cf.
Another stackable pipette tip carrier essentially implemented as a rectangular plate is known from the document EP 2 508 261 A1. Such a pipette tip carrier has a first array of 8×12 through holes, for example, each of which is used to hold a pipette tip on its shaft. In addition, such a pipette tip carrier has a second array, also of 8×12 through holes, each of which lets through a front end of a pipette tip. These two orthogonal arrays having equal lattice constant are arranged offset in relation to one another, wherein this offset is half of the lattice constant in both directions of the lattice. Using multiple such pipette tip carriers, which are each arranged turned by 180° in relation to one another, a very large number of pipette tips can be stored in a space-saving manner, that is in a so-called “interleaved” or “offset” manner, because the ends of the pipette tips held in one pipette tip carrier each penetrate the pipette tip carrier arranged underneath in the stack adjacent to the pipette tips held therein. These pipette tip carriers typically comprise two upwardly oriented handles, which are arranged on the two transverse sides of the plate, and which provide a grasping point for transporting the pipette tip carrier without the pipette tips having to be touched for this transport. These handles are connected to the pipette tip carrier via a jointed tab and comprise a snap tab, using which the pipette tip carrier can be removably fastened in a stack with a storage container. The lowermost pipette tip carrier is always fixed using its snap tabs on the container; after the use of all pipette tips, the empty pipette tip carrier is separated from the container and replaced by the next, lowermost pipette tip carrier of the stack.
A further stackable pipette tip carrier is known from the document US 2006/0045815 A1, which is essentially implemented as a rectangular plate having holes for holding pipette tips and comprises a peripheral cover and a closure mechanism. A corresponding package comprises a pipette tip carrier, a base for supporting the pipette tip carrier, and a closure mechanism on the pipette tip carrier, which is implemented for the external engagement on a side wall of the base; this side wall of the base carries the pipette tip carrier. Such a package can also comprise a removable lid for the pipette tip carrier, wherein this lid can also have a closure mechanism, which is implemented for the external engagement on the cover of the pipette tip carrier or on a side wall of the base. The entirety of base, peripheral cover of the pipette tip carrier, and lid results in a protective package for the pipette tips, which are located in one or more (stacked) pipette tip carriers. In this case, the springy enclosure mechanisms are oriented downward and are accessible at any time from the outside without lifting off the lid. Using multiple such pipette tip carriers, a very large number of pipette tips can be stored in a space-saving manner, that is in a so-called “interlocking” or “nested” manner, because the ends of the pipette tips held in one pipette tip carrier each engage into the pipette tips arranged underneath in the stack.
The document DE 197 42 493 C1 can be considered to be the closest prior art. It describes a magazine for pipette tips having multiple stacking frames stacked one on top of another and holding plates, which are inserted from above at approximately half height in the stacking frame on brackets, having receptacles for the pipette tips. These magazines have a space-saving stacked arrangement having interlocking pipette tip layers. Secure stacking one on top of another is enabled by corresponding structural elements. The essential elements are springy tabs having hooks or locking ribs on the opposing long inner sides of the side walls of the stacking frame and on the short sides of the holding plates, and also corresponding assigned locking elements. The friction-locked and/or formfitting connection (locking) of the uppermost stacking frame to the next lower stacking frame is disengaged by removing the uppermost holding plate (after the processing of the uppermost layer of pipette tips), so that subsequently the uppermost stacking frame can also be lifted off and the next pipette tip layer can be exposed.
It is the object of the present invention to propose an alternative spacer for pipette tip carriers stacked one on top of another, which causes improved centering and stabilization of the carrier stack, without all elements of such a carrier stack having to be locked with one another.
This object is achieved with a spacer having the features of independent claim 1. Such a frame-shaped, essentially rectangular spacer for pipette tip carriers stacked one on top of another comprises a horizontal base surface, a peripheral side wall, which stands essentially perpendicular to the base surface and forms two longitudinal sides and two transverse sides, and an upper surface, wherein each longitudinal side and each transverse side comprises an inner side. Such a spacer according to the invention is characterized in that the upper surface is arranged on an upper end of the side wall and extending essentially horizontally, wherein the spacer is implemented to form a stabilizing support connection to an essentially rectangular pipette tip carrier, which is positioned on the spacer, and it comprises centering spring elements, which are arranged on the inner side of all longitudinal sides and transverse sides, having a springy part spaced apart in relation to the inner side of the respective side wall part, wherein these centering spring elements act upon a pipette tip carrier, on which the spacer lies with horizontal play, and thus act as a centering aid or as a twist lock in the stack.
Such a spacer preferably has a central, essentially rectangular opening, which can be penetrated by a first part of a pipette tip carrier, which is positioned on the spacer and comprises a flange. In such cases, it is especially preferable for the spacer to comprise connecting elements (for example, holding pins) in the region of its upper surface, which are implemented to form a detachable support connection with the flange of this pipette tip carrier.
Alternatively, it can be provided that a spacer is inseparably connected in the region of its upper surface to the flange of an essentially rectangular pipette tip carrier, which is positioned on the spacer, or that a pipette tip carrier/spacer combination is produced in one piece.
Advantages of the spacer according to the invention comprise the following:
The spacer according to the invention will be explained in greater detail on the basis of schematic drawings, which illustrate exemplary embodiments and do not restrict the scope of the present invention. In the figures:
Preferred exemplary embodiments of the spacer according to the invention will now be described in detail. In this case,
The spacer 61 comprises a horizontal base surface 63, a peripheral side wall 64 standing essentially perpendicular to the base surface 63, and an upper surface 65. In the exemplary embodiment shown, a base surface 63, which is set back somewhat in relation to the remaining lower edge of the spacer 61, is located in each corner of the spacer 61. Alternatively, a single peripheral base surface 63 can also be provided; however, the embodiment of this base surface 63 only plays a subordinate role, because in the stack, only the intrinsic weight of the spacer 61 is transmitted via this base surface 63 onto the pipette tip carrier 62 positioned underneath (cf.
The upper surface 65 of the spacer 61 is arranged on an upper end of the side wall 64 and extending essentially horizontally. In the exemplary embodiment shown, an upper surface 65, which connects two of the corners 68 of the spacer 61 to one another, and which is set back somewhat in relation to the remaining upper edge of the spacer 61, is located on both transverse sides of the spacer 61. Alternatively, a single peripheral upper surface 65 can also be provided; however, the embodiment of this upper surface 65 plays a subordinate role, since no forces are transmitted on this upper surface 65 in the stack (cf.
The spacer 61 according to the invention is implemented to form a stabilizing support connection with an essentially rectangular pipette tip carrier 62 positioned on the spacer 61. This support connection is implemented as either separable or inseparable; in any case, it provides a play-free connection between the spacer 61 and the pipette tip carriers 62 positioned immediately above it. In addition, this connection is so stable that when a pipette tip carrier 62 is lifted off of a stack, the spacer 61 according to the invention, which is arranged directly below this pipette tip carrier 62, is lifted off together with the pipette tip carrier 62 from the stack in each case. A spacer 61 according to the invention and the pipette tip carrier 62 positioned directly thereon are therefore always connected to one another via a stabilizing support connection and represent a structural stack unit according to the invention.
As a further element, which is essential to the present invention, the spacer 61 comprises centering spring elements 71, arranged on an inner side 70 of the side wall 64, having a springy part 72 spaced apart in relation to the inner side 70 of the respective side wall 64. The springy parts 72 of the centering spring element 71 of the spacer 61 are preferably arranged on the inner side 70 of the side wall 64 and implemented such that they act upon a second part 80 of an essentially rectangular pipette tip carrier 62, on which the spacer 61 rests with horizontal play, and thus minimize the horizontal play between the underlying pipette tip carrier 62 and the spacer 61 lying thereon (cf.
The centering spring elements 71 shown are arranged at a defined spacing 87 to one another. This spacing 87 is preferably selected, both in relation to the longitudinal sides and also in relation to the transverse sides of the spacers 61, so that the greatest possible distance results between two centering spring elements 71 arranged on the same longitudinal side or transverse side. This arrangement ensures a maximum centering effect or twist barrier in the stack of pipette tip carriers 62.
An inclined or essentially horizontal arrangement of the springy parts 72 of the centering spring elements 71 would have the advantage that the springy parts 72 of the centering spring element 71 could be implemented longer and could be more easily influenced in their spring action; however, the injection molding and subsequent demolding can prove to be more difficult.
Polypropylene is preferred as the material for the production of the spacers 61. However, other plastics capable of injection molding, or plastic blends or composites, can also be used for producing the spacers 61 if needed. Admixed colorants make it easier to recognize the spacers 61, whether during use in a stack or when they are stored as individual parts.
Greatly varying stabilizing support connections are fundamentally conceivable in such a structural stack unit:
If one selects the first embodiment of the spacer 61 according to the invention having four connecting elements 67 implemented as holding pins 67′, it is thus particularly preferable for each holding pin 67′ of the spacer 61 to comprise at least one element 81, which defines the effective cross section 79 of the holding pins 67′. This defining element 81 is preferably selected from a group of elements which define a round, elliptical, oval, polygonal, or star-shaped cross section. Effective cross sections 79 having arbitrary combinations of these shapes are also conceivable. It is particularly preferable for each holding pins 67′ of the spacer 61 to comprise a thickening 83, which, alone or together with further defining elements 81, defines the effective cross section 79 of the holding pins 67′. In addition, it is especially preferable for the element 81, which defines the effective cross section 79 of the holding pin 67′, or the thickening 83 of the holding pin 67′, to comprise a springy part. For the purpose of the automatic centering of holding pin 67′ and centering holes 78 during the joining together of a spacer 61 with the pipette tip carrier 62 positioned thereon, it is preferable for each holding pin 67′ to taper at its upper end 69 with increasing height.
The upper pipette tip carrier 62 comprises a first part 74 arranged below the flange 75 and a second part 80 arranged above the flange 75. These three elements of the pipette tip carrier 62 comprise holding holes 85, which all three elements completely penetrate in the vertical direction. Each of these holding holes 85 is implemented to receive a pipette tip 84, wherein each pipette tip 84 stops with its collar 88 on the upper side of the second part 80 and therefore cannot fall through the holding hole 85. The axis 86 of each pipette tip 84 received in the holding hole 85 is aligned vertically. These axes 86 are preferably arranged in an orthogonal array, which corresponds to the array of the wells of a standard microplate (cf. norm ANSI_SBS 1-4 2004). The flange 75 of this pipette tip carrier 62 comprises four centering holes 78, two of which are shown here. All of these centering holes 78 have a defined cross section 77, to which the effective cross section 79 of the holding pins 67′ of the spacer 61 is adapted.
The lower pipette tip carrier 62 comprises precisely the same elements as the upper pipette tip carrier 62 just described. The pipette tip carriers 62 shown here, which are known from the prior art, are implemented to receive 96 pipette tips 84 in an 8×12 array.
All pipette tip carriers 62 are originally equipped with 96 pipette tips 84. 96 of these pipette tips 84 are always to be offered for usage step-by-step from top to bottom by the pipette tip carriers 62. The structure of such a stack is to be briefly explained:
At the very bottom, a base 89 having a horizontal base surface is used. This base surface essentially corresponds to the footprint of a standard microplate, therefore the base 89 alone, the base 89 together with stack parts, individual stack parts, or also the entire stack can be grasped and transported using a corresponding microplate handling robot. The base 89 has four centering pins 90. These centering pins 90 are dimensioned so that they engage with play in the centering holes 78 of the flange 75 of the first pipette tip carrier 62. The base 89 preferably has four protrusions 91 on its inner side, which hold the first part 74 of the first pipette tip carrier 62 (indicated by dashed lines here) between them in a friction fit. Each pipette tip carrier 62 preferably has catches 94 at four corresponding points of its first part 74, in which the protrusions 91 engage, so that the friction fit is further reinforced. The first pipette tip carrier 62 thus lies without lateral play on the base 89 and is held by the base. As a consequence, the first pipette tip carrier 62 and the base 89 form a first structural stack unit. Notwithstanding this illustration, the first pipette tip carrier 62 can be inseparably connected to the base 89 (for example, by gluing, welding, or one-piece production). However, it is preferable to use a first pipette tip carrier 62 known from the prior art, so that this stabilizing support connection is preferably established by friction fit, gluing, or welding. The described friction fit, which has already proven itself many times, is particularly preferable.
The completely equipped first pipette tip carrier 62 is laid on the base so that its first part sinks into the base 89 and its flange 75 lies on the upper surface of the base 89.
A first spacer 61 is laid on this first pipette tip carrier 62.
This first pipette tip carrier 61 is initially still separated from the pipette tip carrier 62 to be laid thereon. A second pipette tip carrier 62 is then laid on the first spacer 61, so that it's holding pins 67′ are held in the friction fit in the corresponding centering holes 78 in the flange 75 of the second pipette tip carrier 62. The second pipette tip carrier 62 and the first spacer 61 thus together form a structural stack unit.
Alternatively, in each case before being laid on the stack, a pipette tip carrier 62 can be connected to a spacer 61 arranged underneath, in that its holding pins 67′ are held in the friction fit in the corresponding centering holes 78 in the flange 75 of the pipette tip carrier 62.
As a further alternative, it can be provided that before being laid on the stack, in each case a pipette tip carrier 62 is connected to a spacer 61 arranged underneath by gluing or welding.
In each case, it is preferable for a pipette tip carrier 62 and a spacer 61 arranged underneath to form a structural stack unit together (already before or only after being laid on the stack), which can later be lifted off in one piece from the stack.
A second spacer 61 is laid on this second pipette tip carrier 62. This second spacer 61 is initially still separated from the pipette tip carrier 62 to be laid thereon. A third pipette tip carrier 62 is then laid on the second spacer 61, so that its holding pins 67 are held in the friction fit in the corresponding centering holes 78 in the flange 75 of the third pipette tip carrier 62. The third pipette tip carrier 62 and the second spacer 61 thus together form a structural stack unit.
A third spacer 61 is laid on this third pipette tip carrier 62. This third spacer 61 is initially still separated from the pipette tip carrier 62 to be laid thereon. A fourth pipette tip carrier 62 is then laid on the third spacer 61, so that its holding pins 67′ are held in the friction fit in the corresponding centering holes 78 in the flange 75 of the fourth pipette tip carrier 62. The fourth pipette tip carrier 62 and the third spacer 61 thus together form a structural stack unit.
A lid 92 is preferably laid on the very top of a stack.
Uses according to the invention of these spacers 61 comprise the stacking of pipette tip carriers 62, which are spaced apart by means of spacers 61 and are preferably equipped with pipette tips 84. The use of a spacer 61 according to the invention, in which a pipette tip carrier 62 is placed with its flange 75 on the upper surface 65 of the spacer 61, whereby the holding pins 67′ of the spacer 61 are fixed with friction fit in the centering holes 78 of the pipette tip carrier 62, is especially preferred. Furthermore, a use of a spacer 61 according to the invention is preferred, in which the spacer 61 is laid with its base surface 63 on the flange 75 of a pipette tip carrier 62, wherein the springy parts 72 of the centering spring elements 71 of the spacer 61 act upon the second part 80 of an essentially rectangular pipette tip carrier 62, on which the spacer 61 lies with horizontal play, and therefore minimize the horizontal play between the underlying pipette tip carrier 62 and the spacer 61 lying thereon. In addition, a use of a spacer 61 according to the invention is preferred, in which a pipette tip carrier 62 is lifted off together with the spacer 61 fixed thereon from an underlying pipette tip carrier 62; this lifting off can be performed manually, but also using a corresponding robot (not shown) of a liquid handling workstation 93.
All corresponding parts of the spacer 61 according to the invention and the pipette tip carrier 62 known from the prior art were identically numbered and identified, even if these parts were not described in detail in each case.
Number | Date | Country | Kind |
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02127/13 | Dec 2013 | CH | national |