Patent Publication Number: US-11020738-B2

Title: Pipetting device, pipette tip coupler, and pipette tip: devices and methods

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Pursuant to 35 U.S.C. section 119(e) and 120, this application is a continuation of and claims the benefit of priority from U.S. Pat. No. 10,898,892 entitled “Pipetting Device, Pipette Tip Coupler, and Pipette Tip: Devices and Methods” filed on Jul. 31, 2020, which is a continuation-in-part of and claims the benefit of priority from U.S. Pat. No. 10,730,040 entitled “Pipetting Device, Pipette Tip Coupler, and Pipette Tip: Devices and Methods” issued on Aug. 4, 2020, which is a continuation of and claims the benefit of priority from U.S. Pat. No. 10,525,460 entitled “Pipetting Device, Pipette Tip Coupler, and Pipette Tip: Devices and Methods” issued on Jan. 7, 2020, which claims the benefit of priority from two (2) U.S. provisional patent applications, No. 62/350,291 filed on Jun. 15, 2016 and No. 62/350,302 filed on Jun. 15, 2016, all of which are fully incorporated herein by reference. 
    
    
     FIELD 
     This disclosure pertains generally to pipetting devices, and more particularly to pipette tip couplers, disposable pipette tips, pipette tip and coupler combinations, and coupling and decoupling methods of at least one disposable pipette tip to or from at least one pipette tip coupler operatively carried by a pipette device. 
     BACKGROUND 
     Pipette devices are used in a multitude of industries for the transfer of liquids to conduct experimental analysis. As such, to provide control within the experiments being performed, disposable pipette tips are used and intended for one-time use. Disposable pipette tips are employed with both manual pipette devices and automated pipette devices having a large number of pipette units arranged in a row or in a matrix for aspirating samples simultaneously from a large number of vessels and dispensing them elsewhere. 
     Disposable pipette tips have been constructed historically to interface to either a conical or stepped coupling stud. In the cases where a conical coupling stud is used, the disposable pipette tip is constructed in a manner that it must be pre-stressed onto the coupling stud to provide an airtight seal. Due to the tolerances of the two interfacing components, the distance to the end of the pipette tip that comes in contact with liquid is not well controlled. In addition, high press forces are required to pre-stress the pipette tip to create the air tight seal. As a result, microfissures may be formed in the pipette tip, which are a cause of leakage. Moreover, the high press forces upon placement of the pipette tip have the disadvantage that for the release of the pipette tip correspondingly high forces have to be applied. 
     The assignee of the present application, HAMILTON Company, teaches in U.S. Pat. No. 7,033,543, issued Apr. 25, 2006, a stepped coupling stud in conjunction with an O-ring that provides a solution for reducing the high press force required to create an air tight seal as well as providing well defined axial positioning of the end of the pipette tip that comes in contact with liquid. As the O-ring is compressed, it provides axially directed force to not only provide the air-tight seal, but to engage the axial coupling feature on the coupling stud to the counter axial coupling feature on the pipette tip. 
     Notwithstanding, current systems utilizing a stepped coupling stud and a solitary O-ring configuration are problematic when the O-ring becomes compromised because the result is an impairment in the air-tight seal and the performance of the pipette device. 
     Additionally, the compression of the O-ring results in the deformation of the O-ring which in turn provides the axially directed force and air-tight seal against the working surface of the pipette tip. Counter to this operation, when the compression of the O-ring is removed, the O-ring must disengage from the working surface of the pipette tip to allow the pipette tip to be removed from the coupling stud and the pipette device for disposal. If the O-ring does not fully decompress, some residual force will remain resulting in keeping the pipette tip engaged to the coupling stud and thus requiring an automated external axial counterforce to remove the pipette tip for disposal. 
     Moreover, as the size of the holes to and/or from which liquid is transferred decreases, the need for precision positioning of all of the pipette tips in a controlled manner increases in order to allow successful targeting. 
     Hence, there is a need to ameliorate or overcome one or more of the significant shortcomings delineated hereinabove. 
     SUMMARY 
     Accordingly, and in one aspect, an embodiment of the present disclosure ameliorates or overcomes one or more of the shortcomings of the known prior art by providing a pipette tip coupler and disposable pipette tip combination which comprises a plurality of circumferentially disposed elements or segments engaging a circumferential interior working surface defining a first working surface formed into an interior circumscribing surface of a sidewall of the pipette tip in an area superior to a proximally facing axial stop surface of the pipette tip for providing a resultant pre-stress force which pre-stresses the pipette tip axially upward causing a distal elastomeric element of the coupler to be pre-stressed against a second interior working surface of the pipette tip forming a seal configuration that eliminates the seal deterioration or failure of the known prior art. 
     In addition, and in one aspect, the distal elastomeric element, when compressed against the second interior working surface, provides a counter axial force to the plurality of elements or segments wherein at least one benefit of this counter axial force is that additional force is applied to the first working surface by the plurality of individual elements or segments when the plurality of individual elements or segments are in a radially and axially interfacing state for providing a stronger distal seal. 
     A further benefit of the counter axial force is that when the plurality of individual elements or segments are disengaged to a radially retracted state, the counter axial force of the distal elastomeric element defines a counter axially directed disengaging force that aids in the removal of the pipette tip from the pipette tip coupler for disposal. 
     In another aspect, an embodiment of the present disclosure provides a pipette tip coupler and disposable pipette tip combination, the coupler comprising a plurality of circumferentially disposed elements or segments and a distal elastomeric element in the form of, but not limited to, an O-ring and the pipette tip comprising dual complemental interior working surfaces in the pipette tip to provide a resultant axial force achieved from an engagement of the plurality of elements or segments and the distal elastomeric element with the dual complemental working surfaces for pre-stressing the disposable pipette tip into an axial coupling position which is provided by a distally facing axial stop surface of the pipette tip coupler and a proximally facing complimentary counter axial stop surface of the disposable pipette tip such that a perpendicular datum is established to a longitudinal axis of a channel of a pipette device carrying the pipette tip coupler and disposable pipette tip combination which provides for pipette tip straightness and controlled concentricity. 
     Thus, one benefit of the resultant axial force coupling position over the known prior art is the establishment of this perpendicular datum which provides for pipette tip straightness and controlled concentricity. Concentricity becomes worse as an angle defined herein as “ø” between a transverse axis and the longitudinal axis perpendicular to the transverse axis is allowed to increase. Thus, controlled concentricity becomes especially important on a multi-channel system and targeting multiple wells. Accordingly, the pipette tip coupler and disposable pipette tip combination provides tighter concentricity to allow for tighter precision of all the pipette tips in a controlled manner allowing successful targeting of multiple wells and/or smaller holes to and/or from which liquid is transferred. 
     In another aspect, an embodiment of the present disclosure provides a pipette tip coupler and disposable pipette tip combination, the coupler comprising a plurality of circumferentially disposed elements or segments and a distal elastomeric element in the form of, but not limited to, an O-ring and the pipette tip comprising dual complemental working surfaces in the pipette tip to provide precise control of an axial coupled position defined as an axial distance from a distally facing axial stop surface of the pipette tip coupler to the end of the pipette tip that contacts liquid when the pipette tip coupler and disposable pipette tip are in a coupled configuration. This, combined with pipette tip straightness, allows for a pipette device carrying the pipette tip coupler and disposable pipette tip combination to target smaller holes. Additionally, smaller volumes of liquid can be transferred resulting from the known fixed distance of the disposable pipette tip allowing for a controlled touch of the pipette tip/liquid to a working surface onto or from which liquid is to be transferred. 
     In yet another aspect, an embodiment of the present disclosure provides a pipette tip coupler and disposable pipette tip combination comprising an angled squeeze mechanism that directs the motion of the plurality of individual elements into contact with the first working surface of the pipette tip. The result is more axial force to pre-stress the pipette tip into the axial coupling position. 
     In yet another aspect, an embodiment of the present disclosure provides a pipette tip coupler and disposable pipette tip combination, the coupler comprising a plurality of circumferentially disposed elements or segments in the form of flexible leaf springs with retention bumps to retain a pipette tip to the coupler, stabilizer plateaus to prevent the pipette tip from rocking on the coupler and a distal elastomeric element in the form of, but not limited to, an O-ring and the pipette tip comprising dual complemental working surfaces in the pipette tip to provide precise control of an axial coupled position defined as an axial distance from a distally facing axial stop surface of the pipette tip coupler to the end of the pipette tip that contacts liquid when the pipette tip coupler and disposable pipette tip are in a coupled configuration. 
     Further aspects of the embodiments of the present disclosure will become apparent from the detailed description provided below, when taken together with the attached drawings and claims. It should be understood, however, that numerous modifications and adaptations may be resorted to without departing from the scope and fair meaning of the claims as set forth below following the detailed description of preferred embodiments of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The foregoing summary, as well as the following detailed description of the disclosure, will be more fully understood by reference to the following drawings which are for illustrative purposes only, and are not intended to limit the scope of the present disclosure. Also, it is appreciable that the drawings are not necessarily in scale as some components may be shown to be enlarged or to be out of proportion relative to the size in actual implementation in order to more clearly illustrate one or more concepts of the present disclosure. In the drawings: 
         FIG. 1  is a perspective view of an example embodiment of an air displacement pipette device assembly of an automated liquid handling system. 
         FIG. 2  is a longitudinal sectional, side elevational view of the example embodiment of the pipette device assembly. 
         FIG. 3  is a fragmentary longitudinal sectional, side elevational view of the example embodiment of the pipette device assembly comprising a pipette device operatively coupled to an example embodiment of an expanding mandrel collet coupling device or pipette tip coupler that is operatively coupled to an example embodiment of a disposable pipette tip. 
         FIG. 4  is a side elevational view of the example embodiment of the pipette device assembly. 
         FIG. 5  is a partial exploded parts perspective view of the pipette device assembly detailing parts of the example embodiment of the expanding mandrel collet coupling device. 
         FIG. 6  is a fragmentary, partial exploded parts perspective view detailing parts of the example embodiment of the expanding mandrel collet coupling device interposed between the disposable pipette tip and the pipette device. 
         FIG. 7  is a side elevational view of the example embodiment of the expanding mandrel collet coupling device. 
         FIG. 8  is a top and side perspective view of a central coupler body of the example embodiment of the expanding mandrel collet coupling device. 
         FIG. 9  is a top and side perspective view of an example embodiment of a lower or distal elastomeric element or O-ring of the example embodiment of the expanding mandrel collet coupling device. 
         FIG. 10  is a top and side perspective view of the distal elastomeric element circumscribing a distal stem portion of the central coupler body and a cylindrical spacer circumscribing and mounted on the central body axially above the distal elastomeric element. 
         FIG. 11  is a top and side perspective view of an example embodiment of an expanding mandrel collet of the expanding mandrel collet coupling device. 
         FIG. 12  is a longitudinal sectional, side perspective view of the example embodiment of the expanding mandrel collet of the expanding mandrel collet coupling device. 
         FIG. 13  is a top and side perspective view of an example embodiment of an annular wedge of the example embodiment of the expanding mandrel collet coupling device. 
         FIG. 14  is a side elevational view of the example embodiment of the expanding mandrel collet in an expanded configuration by application of a force from a piston sleeve or squeeze sleeve illustrated in fragment. 
         FIG. 15  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the expanding mandrel collet of the expanding mandrel collet coupling device operatively coupled to the pipette device. 
         FIG. 16  is a fragmentary, partially sectional, side elevational view of the example embodiment of the disposable pipette tip operatively coupled to the pipette device by way of the embodiment of the expanding mandrel collet coupling device. 
         FIG. 17  is a side elevational view of the example embodiment of the disposable pipette tip illustrated in a supported position. 
         FIG. 18  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the disposable pipette tip detailing the interior thereof. 
         FIG. 19  is a fragmentary, longitudinal sectional, side elevational view of an upper coupling portion of the example embodiment of the disposable pipette tip detailing the upper coupling interior thereof. 
         FIG. 20  diagrammatical block diagram view of an example embodiment of an automated pipetting workstation or system. 
         FIG. 21  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the pipette device supporting the example embodiment of the expanding mandrel collet coupling device over the disposable pipette tip. 
         FIG. 22  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the expanding mandrel collet coupling device positioned over and into the disposable pipette tip defining a coupling stage with the distal elastomeric element initially contacting a sealing seat surface of the pipette tip and with the plurality of discrete coupling elements or segments in an unsqueezed or radially outwardly unextended state, the sealing seat surface having an acute sealing seat surface angle relative to the central longitudinal axis of the pipette tip. 
         FIG. 23  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the expanding mandrel collet coupling device and pipette tip with the pipette tip being lifted as a result of the piston sleeve pushing down on the annular wedge for radially extending a rounded part of a plurality of expanding mandrel collet segments against an upper corner of a groove formed in the pipette tip resulting in an axial force that lifts or pulls the pipette tip up which starts the process of seating the pipette tip and compressing the distal elastomeric element against the sealing seat surface of the pipette tip. 
         FIG. 24  is a fragmentary, longitudinal sectional, side elevational detailed view of the rounded surface of one of the plurality of expanding mandrel collet segment arms of the expanding mandrel collet of the segmented coupler being extended into contact with the corner of the groove of the pipette tip as is illustrated in  FIG. 23 . 
         FIG. 25  is a fragmentary, longitudinal sectional, side elevational detailed view of the distal elastomeric element in an initial compressed state against the sealing seat surface of the pipette tip as is illustrated in  FIG. 23 . 
         FIG. 26  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the expanding mandrel collet coupling device positioned yet further into the pipette tip with the pipette tip being lifted while the piston sleeve further forces down on the annular wedge to continue radially extending the rounded surface of the plurality of expanding mandrel collet segments into the groove of the pipette tip further pulling the pipette tip up and further compressing the distal elastomeric element against the sealing seat surface of the pipette tip. 
         FIG. 27  is a fragmentary, longitudinal sectional, side elevational detailed view of the rounded surface of one of the plurality of expanding mandrel collet segments being further extended into the groove of the pipette tip as is illustrated in  FIG. 26 . 
         FIG. 28  is a fragmentary, longitudinal sectional, side elevational detailed view of the distal elastomeric element being further compressed from the initial compressed state against the sealing seat surface of the pipette tip as is illustrated in  FIG. 26 . 
         FIG. 29  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the expanding mandrel collet coupling device positioned in the disposable pipette tip with the pipette tip being lifted up to its final seated state by the annular wedge being moved to its final position thereby defining a final coupling state with the distal elastomeric element in a final compressed seated sealing state against the sealing seat surface of the pipette tip. 
         FIG. 30  is a fragmentary, longitudinal sectional, side elevational detailed view of the rounded surface of one of the plurality of expanding mandrel collet segments being extended into abutment with the surface defining the groove as is illustrated in  FIG. 29 . 
         FIG. 31  is a fragmentary, longitudinal sectional, side elevational detailed view of the distal elastomeric element in the final compressed seated sealing state against the sealing seat surface of the pipette tip as is illustrated in  FIG. 29 . 
         FIG. 32  is a fragmentary, longitudinal sectional, side elevational, detailed view of onset of a coupling between the example embodiments of the expanding mandrel collet coupling device and disposable pipette tip with an illustration of associated forces. 
         FIG. 33  is a fragmentary, longitudinal sectional, side elevational, detailed view of the onset of coupling of one of a plurality of arcuate or rounded segment surfaces of one of the plurality of expanding mandrel collet segments with the groove of the example embodiment of the disposable pipette tip with an illustration of associated forces. 
         FIG. 34  is a fragmentary, longitudinal sectional, side elevational, detailed view of the completed coupling state between the example embodiments of the expanding mandrel collet coupling device and disposable pipette tip with an illustration of associated forces. 
         FIG. 35  is a fragmentary, longitudinal sectional, side elevational view illustrating a misaligned coupling between example embodiments of an expanding mandrel collet coupling device and disposable pipette tip for defining misalignment parameters. 
         FIG. 36  is a fragmented and cutaway, longitudinal sectional, side elevational view of an embodiment of a pipette device operatively coupled to a misaligned coupling between example embodiments of an expanding mandrel collet coupling device and disposable pipette tip for defining misalignment parameters. 
         FIG. 37  is a fragmented and cutaway, longitudinal sectional, side elevational view of the example embodiments of the air displacement pipette device coupled to the expanding mandrel collet coupling device that is coupled to the disposable pipette tip that has a small liquid volume interposed between the end of the pipette tip and a working surface and the view further having dimensioning lines illustrated and identified. 
         FIG. 38  is a fragmentary, longitudinal sectional, side elevational view detailing the interior of the example embodiment of the disposable pipette tip and the view further having dimensioning lines illustrated and identified. 
         FIG. 39  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the pipette device operatively coupled to the example embodiment of the expanding mandrel collet coupling device with dimensioning lines relative to the dimensioning lines in  FIG. 38  illustrated and identified. 
         FIG. 40  is a longitudinal side elevational view of the pipette device assembly illustrating a circuit board that processes the signal from a Liquid Level Detection (LLD) circuit contact wherein the LLD circuit contact is connected between the circuit board and squeeze sleeve that is in contact with via an annular wedge the plurality of segments or elements coupling with the pipette tip wherein the distal end of the pipette tip is illustrated in contact with the liquid. 
         FIG. 41  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the expanding mandrel collet coupling device positioned over the example embodiment of the disposable pipette tip comprising an alternative sealing seat surface angle of substantially ninety degrees relative to the central longitudinal axis of the pipette tip. 
         FIG. 42  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the expanding mandrel collet coupling device positioned in the disposable pipette tip comprising the alternative sealing seat surface angle of substantially ninety degrees wherein the pipette tip is lifted up to its final seated state and the annular wedge moved into its final position for defining a final coupling state with the distal elastomeric element in a final compressed and seated sealing state against the alternative sealing seat surface angle of substantially ninety degrees. 
         FIG. 43  is a fragmentary, longitudinal sectional, side elevational detailed view of the distal elastomeric element in the final compressed state against the alternative sealing seat surface angle of substantially ninety degrees as is illustrated in  FIG. 42 . 
         FIG. 44  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the disposable pipette tip illustrating detail of the upper interior of the disposable pipette tip comprising another alternative sealing seat surface in the form of a circumferential radially concave sealing seat surface. 
         FIG. 45  is a fragmentary, longitudinal sectional, side elevational detailed view of the example embodiment of the disposable pipette tip illustrating detail of the circumferential radially concave sealing seat surface illustrated in  FIG. 44 . 
         FIG. 46  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the disposable pipette tip illustrating detail of a further alternative sealing seat surface in the form of a circumferential radially convex sealing seat surface. 
         FIG. 47  is a fragmentary, longitudinal sectional, side elevational detailed view of the example embodiment of the disposable pipette tip illustrating detail of the circumferential radially convex sealing seat surface illustrated in  FIG. 46 . 
         FIG. 48  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the disposable pipette tip illustrating a yet further alternative sealing seat surface in the form of a circumferential upward facing tooth edge sealing seat surface. 
         FIG. 49  is a fragmentary, longitudinal sectional, side elevational detailed view of the example embodiment of the disposable pipette tip illustrating detail of the circumferential upward facing tooth edge sealing seat surface illustrated in  FIG. 48 . 
         FIG. 50  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the expanding mandrel collet coupling device positioned over the example embodiment of the disposable pipette tip comprising an alternative V-shaped groove defined by an V-shaped circumferential interior surface of the disposable pipette tip opening toward the longitudinal axis and having a V-shaped cross section as illustrated. 
         FIG. 51  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the expanding mandrel collet coupling device positioned in the disposable pipette tip comprising the alternative V-shaped groove wherein the pipette tip is lifted up to its final state with the rounded surfaces of the plurality of expanding mandrel collet segments being extended into the V-shaped groove and into abutment against the V-shaped circumferential interior surface with the distal elastomeric element in a final compressed and seated sealing state against the sealing seat surface of the pipette tip. 
         FIG. 52  is a fragmentary, longitudinal sectional, side elevational detailed view of the rounded surface of one of the plurality of expanding mandrel collet segments being extended into the V-shaped groove and abutting against the V-shaped circumferential interior surface defining the V-shaped groove as is illustrated in  FIG. 51 . 
         FIG. 53  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the expanding mandrel collet coupling device positioned over a second example embodiment of the disposable pipette tip. 
         FIG. 54  is a fragmentary, longitudinal sectional, side elevational detailed view detailing the interior of the second example embodiment of the disposable pipette tip. 
         FIG. 55  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the expanding mandrel collet coupling device positioned in the second example embodiment of the disposable pipette tip with a stop disk shoulder surface of the coupling device abutting against an axial stop surface of the second example embodiment of the disposable pipette tip and the rounded surfaces of the plurality of expanding mandrel collet segments being extended against an interior surface of a circumscribing sidewall of the second example embodiment of the disposable pipette tip resulting in a deformation of the interior surface and with the distal elastomeric element in a final compressed and seated sealing state against the sealing seat surface of the second example embodiment of the disposable pipette tip. 
         FIG. 56  is a fragmentary, longitudinal sectional, side elevational detailed view of the rounded surface of one of the plurality of expanding mandrel collet segments of the expanding mandrel collet coupling device being extended against and deforming the interior surface of the circumscribing sidewall of the second example embodiment of the disposable pipette tip as is illustrated in  FIG. 55 . 
         FIGS. 57 through 67  are fragmentary, longitudinal sectional, side elevational views of the example embodiment of the disposable pipette tip comprising alternative groove shape embodiments relative to the circumferential annular tip groove illustrated in at least  FIG. 19 . 
         FIG. 68  is a top and side perspective view of a second or alternative example embodiment of an expanding mandrel collet of the expanding mandrel collet coupling device. 
         FIG. 69  is a longitudinal sectional, side perspective view of the second or alternative example embodiment of the expanding mandrel collet of the expanding mandrel collet coupling device. 
         FIG. 70  is a perspective view of an alternative example embodiment of an air displacement pipette device assembly of an automated liquid handling system. 
         FIG. 71  is a longitudinal sectional, side elevational view of one side of the alternative example embodiment of the pipette device assembly. 
         FIG. 72  is a fragmentary, longitudinal sectional, side elevational view of another side of the alternative example embodiment of the pipette device assembly. 
         FIG. 73  is a partial exploded parts view of the pipette device assembly detailing parts of the pipette device illustrated in  FIG. 72 . 
         FIG. 74  is a partial exploded parts perspective view of the pipette device assembly detailing parts of the example embodiment of a nozzle and a leaf spring coupling device. 
         FIG. 75  is a fragmentary, partial exploded parts perspective view detailing parts of the example embodiment of a nozzle and a leaf spring coupling device interposed between the disposable pipette tip and the pipette device. 
         FIG. 76  is a side elevational view of the example embodiment of a leaf spring coupling device. 
         FIG. 77  is a top and side perspective view of the example embodiment of the leaf spring coupling device. 
         FIG. 78  is a top and side perspective view of an example embodiment of a lower or distal elastomeric element or O-ring of the example embodiment of the leaf spring coupling device. 
         FIG. 79  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the nozzle and the leaf spring coupling device operatively coupled to the pipette device. 
         FIG. 80  is a fragmentary, partially sectional, side elevational view of the example embodiment of the disposable pipette tip operatively coupled to the pipette device by way of the embodiment of the nozzle and the leaf spring coupling device. 
         FIG. 81  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the pipette device supporting the example embodiment of the nozzle and the leaf spring coupling device over the disposable pipette tip. 
         FIG. 82  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the nozzle and leaf spring coupling device positioned over and into the disposable pipette tip defining a coupling stage with the leaf springs compressed, with the retention bumps beginning to enter the groove of the pipette tip, and with the distal elastomeric element initially contacting a sealing seat surface of the pipette tip, the sealing seat surface having an acute sealing seat surface angle relative to the central longitudinal axis of the pipette tip. 
         FIG. 83  is a fragmentary, longitudinal sectional, side elevational detailed view of the rounded surface of one of the plurality of retention bumps of one of the leaf springs of the leaf spring coupling device being in contact with the corner of the groove of the pipette tip as is illustrated in  FIG. 82 . 
         FIG. 84  is a fragmentary, longitudinal sectional, side elevational detailed view of the distal elastomeric element in initial contact with the sealing seat surface of the pipette tip as is illustrated in  FIG. 82 . 
         FIG. 85  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the nozzle, the leaf spring coupling device and pipette tip with the retention bumps of the leaf springs snapped into the groove of the pipette tip and the distal elastomeric element compressed and seated against the sealing seat surface of the pipette tip. 
         FIG. 86  is a fragmentary, longitudinal sectional, side elevational, detailed view of the onset of coupling of one of a plurality of arcuate or rounded segment surfaces of a retention bump of a leaf spring with the groove of the example embodiment of the disposable pipette tip with an illustration of associated forces. 
         FIG. 87  is an fragmentary, longitudinal sectional, side elevational, detailed view of the onset of coupling of one of a plurality of arcuate or rounded segment surfaces of a retention bump of a leaf spring with the groove of the example embodiment of the disposable pipette tip with an illustration of associated forces. 
         FIG. 88  is a fragmentary, longitudinal sectional, side elevational, detailed view of the completed coupling state between the example embodiments of the leaf spring coupling device and disposable pipette tip with an illustration of associated forces. 
         FIG. 89  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the pipette device operatively coupled to the example embodiment of the leaf spring coupling device with Z axis shown. 
         FIG. 90  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the leaf spring coupling device positioned in the disposable pipette tip comprising the alternative sealing seat surface angle of substantially ninety degrees wherein the pipette tip is lifted up to its final seated state with the distal elastomeric element in a final compressed and seated sealing state against the alternative sealing seat surface angle of ninety degrees. 
         FIG. 91  is a fragmentary, longitudinal sectional, side elevational detailed view of the distal elastomeric element in the final compressed state against the alternative sealing seat surface angle of ninety degrees as is illustrated in  FIG. 90 . 
     
    
    
     DETAILED DESCRIPTION 
     For the purpose of illustrating the disclosure, there are shown in the drawings embodiments which are presently preferred. These example embodiments will now be described more fully with reference to the accompanying drawings wherein like reference numerals are used to denote like parts or portions throughout the description of the several views of the drawings. 
     Pipette Assembly with Expanding Mandrel Collet Coupling and Tip 
       FIGS. 1 and 2  illustrate an example embodiment of a pipette device assembly  10  comprising an example embodiment of a pipette device  20 , an example embodiment of an expanding mandrel collet coupling device  100  or pipette tip coupler, and an example embodiment of a disposable pipette tip  220  removably coupled to the pipette device  20  by way of the expanding mandrel collet coupling device  100 . 
     Pipette Device  20   
     Referring to  FIG. 2 , the pipette device  20  comprises a body  22  supporting an aspirating and dispensing device  24  comprising a plunger  26  operatively coupled to and driven by a motor  28 . The plunger  26  resides within a plunger cylinder  30  extending from a distal or lower end  32  of the body  22  of the pipette device  20 . 
     Pipette device  20  further comprises an aspirating and dispensing cylinder  34  that is at least partially disposed within plunger cylinder  30  at a location axially aligned with and distally below the plunger  26 . The aspirating and dispensing cylinder  34  distally transitions into a distal mounting flange  36  for attaching with the expanding mandrel collet coupling device  100  which, in turn, removably couples with the disposable pipette tip  220 . 
     Referring to  FIGS. 1, 3, and 15 , the aspirating and dispensing cylinder  34  further comprises an interior circumscribing sidewall  38  that defines an open ended pipette channel  40  extending therethrough. The open ended pipette channel  40  longitudinally extends along a longitudinal channel axis  80  of the pipette device assembly  10  between an open upper end portion  42  and open lower end portion  44  of the aspirating and dispensing cylinder  34  for providing open communication between plunger  26  and an exterior area adjacent distal mounting flange  36  wherein the distal mounting flange  36  is operatively connected to a central body member  102  of the expanding mandrel collet coupling device  100  and the central body member  102  comprising an open ended central channel  136  extending through the central body member  102  to provide open communication between the tip  220  and the aspirating and dispensing cylinder  34  via the expanding mandrel collet coupling device  100 . 
     Piston or Squeeze Sleeve  46   
     Referring to  FIGS. 3 and 4 , the pipette device  20  further comprises a hollow piston or squeeze sleeve  46  having a proximal or upper end  48  and a distal or lower end  50 . The squeeze sleeve  46  circumscribes both the plunger cylinder  30  and the aspirating and dispensing cylinder  34  and is operatively coupled to a squeeze motor  52 . 
     As illustrated in  FIG. 4 , the squeeze motor  52  of pipette device assembly  10  is supported on the body  22  of the device  20  and is operatively coupled to and drives a lead screw  54  which, in turn, couples to an axially translating lead nut  56  that is operatively coupled to a squeeze linkage  58 . The squeeze linkage  58  is operatively coupled to the proximal or upper end  48  of the squeeze sleeve  46  via squeeze linkage arm  60  such that rotation of the squeeze motor  52  in a first direction results in linear axial translation of the squeeze sleeve  46  in a distal or vertically downward direction along longitudinal channel axis  80  ( FIG. 3 ) and such that subsequent rotation of the squeeze motor  52  in a second or opposite direction results in linear counter axial translation of the squeeze sleeve  46  in a proximal or vertically upward direction opposite the downward direction along longitudinal channel axis  80  ( FIG. 3 ). 
     Ejection Sleeve  62   
     Referring to  FIG. 4 , the pipette device  20  further comprises an ejection sleeve  62  used to eject the disposable pipette tip  220  from the pipette device  20  wherein the ejection sleeve  62  is axially movable relative to the aspirating and dispensing cylinder  34  ( FIG. 2 ) and comprises a proximal or upper end  64 , a distal or lower end  66 , and an ejection sleeve arm  68  attached at a first end to the ejection sleeve  62  adjacent upper end  64  and having an opposing second end attached to a first end of a plunger device  70 . 
     As illustrated in  FIG. 5 , the plunger device  70  comprises an opposing end surface  72  abutting one end of an ejection sleeve spring  74  having an opposing spring end abutting against an upper surface portion  76  of the body  22  of device  20  wherein the ejection sleeve spring  74  is captured between the surfaces  72 ,  76  to be spring loaded to bias the plunger device  70  and attached sleeve  62  in a normally pipette tip ejected state. 
     The normally pipette tip ejected state is configured to require a force, such as coupling to pipette tip  220 , to overcome the ejection sleeve spring force in order to axially push the ejection sleeve  62  to a retracted state as illustrated in  FIG. 2 .  FIG. 2  further illustrates that the spring  74  circumscribes a central spring guide member  78  for retaining the shape of the spring  74  and for preclude the spring  74  from buckling. 
     Furthermore, the spring  74  is dimensioned in such a way that the force exerted on the pipette tip  220  by sleeve  62  in the course of its relaxation is sufficient to assist in ejecting the tip  220  from the expanding mandrel collet coupling device  100 . 
     It should be appreciated that the expanding mandrel collet coupling device  100  and the disposable pipette tip  220  can be practiced on other embodiments of pipette devices wherein the embodiment of pipette device  20  is provided by way of example only and not limitation. 
     Expanding Mandrel Collet Coupling Device  100   
     Referring to  FIGS. 5 through 7 , the expanding mandrel collet coupling device  100  comprises an elongated central body member  102 ; a distal or lower elastomeric element  140  carried at a distal or lower end portion of the elongated central body member  102 ; an expanding collet  170  configured to circumscribe the elongated central body member  102  and comprising a segmented collar  200 ; and an annular wedge or washer  210 . 
     The annular wedge  210  is configured to receive an upper portion of the elongated central body member  102  therethrough for axially movably surmounting an interior of the expanding collet  170  adjacent segmented collar  200  for radially outwardly expanding the segmented collar  200  from the unexpanded state having a first circumference to an expanded state having a second conference greater than the first circumference as a function of the axial location of the annular wedge  210  relative to the central body member  102  for engaging the interior of the pipette tip  220  as illustrated in  FIG. 29  from a disengaged state as illustrated in  FIG. 21 . 
     Elongated Central Body Member  102   
     More specifically, and referring to  FIGS. 7 and 8 , the expanding mandrel collet coupling device  100  comprises the elongated central body member  102  extending between a proximal or upper annular end face  104  and a distal or lower annular end face  130  along a longitudinal central axis  90 . 
     As illustrated in  FIG. 8 , the upper annular end face  104  of central body member  102  comprises an outer chamfered periphery  106  that transitions into an elongated tubular upper shank member  108  that distally transitions into an annular tapered portion  110 . In one embodiment, shank member  108  is threaded for assembly with distal mounting flange  36 , which has corresponding threads. Annular tapered portion  110  decreases in diameter from shank member  108  and distally transitions into a cylindrical neck portion  112 . The cylindrical neck portion  112  distally transitions into a cylindrical collar  114  that has a diameter greater than a diameter of the cylindrical neck portion  112 . 
     The cylindrical collar  114  is followed by a lower cylindrical body member  120  that has a diameter greater than a diameter of the cylindrical neck portion  112 . Body member  120  distally extends from the cylindrical collar  114  to an upper annular shoulder end or stop surface  122  of a distal cylindrical stem portion surface  124  that has a diameter greater than a diameter of the lower cylindrical body member  120 . 
     As also illustrated in  FIG. 8 , the distal cylindrical stem portion surface  124  transitions from upper annular shoulder end  122  into a round end plate  126  having an upper surface  128  and a lower surface defined by the distal or lower annular end face  130 . As illustrated, the end plate  126  has a diameter greater than a diameter of the stem portion surface  124  wherein the distal stem portion surface  124  defines a distal or lower groove portion  132  of the expanding mandrel collet coupling device  100 . 
     Referring to  FIGS. 8 and 15 , the elongated central body member  102  comprises an interior cylindrical channel surface  134  defining an open ended cylindrically shaped central channel or passageway  136  extending through the central body member  102  between the upper annular end face  104  and the lower annular end face  130  along the longitudinal central axis  90  for providing open channel communication through the elongated central body member  102  and to the open ended pipette channel  40  longitudinally extending along the longitudinal channel axis  80  of the pipette device assembly  10 . 
     Distal Elastomeric Element  140   
     As further illustrated in  FIG. 7 , the expanding mandrel collet coupling device  100  further comprises the distal or lower elastomeric element  140  coaxially carried at the distal end portion of the elongated central body member  102 . 
     In one embodiment, and referring  FIG. 9 , the distal elastomeric element  140  comprises an annular body  142 . Annular body  142  comprises an interior surface  144  defining a central opening  146 , a top surface  148 , a peripheral exterior surface  150 , and a bottom surface  152 . Central opening  146  is dimensioned to closely or tightly circumscribe the distal cylindrical stem portion  124  of the expanding mandrel collet coupling device  100  while shaped to reside within groove  132  and extend radially outwardly circumferentially beyond end plate  126  as illustrated in  FIG. 7 . In a relaxed or unsqueezed state, the distal elastomeric element  140  comprises a circumferentially continuous, generally circular cross section area  154  as is illustrated in  FIG. 15 . 
     Spacer  160   
     Referring to  FIG. 10 , the expanding mandrel collet coupling device  100  further comprises a spacer  160  configured to circumscribe or be integrally formed with the elongated central body member  102 . As illustrated, spacer  160  comprises a cylindrical body  162  extending between a superior end  164  and an inferior end  165 . The cylindrical body  162  comprises an interior circumscribing surface  166  ( FIG. 15 ) that defines an open ended passageway  168  extending through the body  162  wherein the passageway  168  is dimensioned to closely or tightly circumscribe the lower cylindrical body member  120  of the elongated central body member  102 . 
     Referring to  FIGS. 7, 10, and 15 , the spacer  160  is further configured to be circumscribed by the expanding mandrel collet  170  wherein the superior end  164  of spacer  160  abuts against the distal end of the mounting flange  36  and the inferior end  165  abuts against an interior annular shoulder stop surface  177  of a annular base portion  172  of the expanding mandrel collet  170  wherein the annular base portion  172  further comprise a distal or lower annular end  176  that mounts on the distal annular shoulder stop surface  122  of the distal cylindrical stem portion  124  ( FIG. 8 ) of the elongated central body member  102  for securing the expanding mandrel collet  170  coaxially with the central body member  102  along the longitudinal central axis  90 . 
     Referring to  FIGS. 15 and 16 , and as noted above, the shank member  108  of the expanding mandrel collet coupling device  100  is configured to fit within the distal mounting flange  36  of the aspirating and dispensing cylinder  34  for operatively coupling the expanding mandrel collet coupling device  100  to the pipette device  20  and removably coupling the disposable pipette tip  220  to the pipette device  20  by way of the expanding mandrel collet coupling device  100  such that the longitudinal channel axis  80  and central axis  90  form a coincident or common longitudinal channel axis. 
     Expanding Mandrel Collet  170   
     Referring to  FIGS. 7 and 11 , the expanding mandrel collet  170  comprises a plurality of circumferentially spaced apart upwardly extending collet arms  180  transitioning upwardly from ends  184  attached to the lower annular base portion  172  to free segmented ends  200  defining the segmented collar disposed axially above the lower annular base portion  172 . The plurality of circumferentially spaced apart upwardly extending collet arms  180  are separated from one another by one of a plurality of circumferentially spaced apart upwardly extending slots  182 . 
     As illustrated in  FIGS. 11 and 12 , each of the plurality of upwardly extending collet arms  180  comprises a respective lower arm portion  186  transitioning into a respective upper arm portion  190 . In one embodiment, the plurality of circumferentially spaced apart lower arm portions  186  form a generally cylindrically shaped circumscribing lower body portion  181  and the plurality of circumferentially spaced apart upper arm portions  190  form a frustoconically shaped circumscribing upper body portion  183  radially outwardly and upwardly transitioning from the lower body portion  181 . The lower body portion  181  can be configured with a slight upward taper or increased circumference with respect the distal or lower annular base portion  172 . 
     Base Portion  172   
     Referring to  FIGS. 11 and 12 , the distal or lower annular base portion  172  comprises a distally or downwardly facing base surface  171  and a proximally or upwardly facing base surface  173 . The distally facing base surface  171  downwardly transitions into an abbreviated distal or lower end annular stem surface  174  that terminates to a distal or lower annular base portion end  176  of the lower annular base portion  172 . The base surface  171  and base portion  172  define an abbreviated distal end annular groove  178  as illustrated in  FIG. 14 . 
     Referring to  FIGS. 12 and 15 , the lower annular base portion  172  further comprises an inner cylindrical surface  175  upwardly transitioning into the interior annular shoulder stop surface  177  on which spacer  160  is mounted on as illustrated in  FIG. 15 . Additionally, the inner cylindrical surface  175  is dimensioned with an inner diameter that closely circumscribes lower cylindrical body member  120  of central body member  102  at a location directly above the annular shoulder stop surface  122  of central body member  102  wherein the annular shoulder stop surface  122  defines the axial stop for the lower annular base portion end  176  of the expanding mandrel collet  170  such that the expanding mandrel collet  170  is centrally mounted on and about the elongated central body member  102 . 
     Lower Arm Portions  186   
     As illustrated in  FIG. 11 , the lower arm portions  186  comprise distal or lower end portions  184  circumferentially spaced apart and attached to the lower annular base portion  172 . As illustrated in  FIG. 12 , the lower arm portions  186  further comprise upper end portions defining medial arm portions having interior annular recessed segmented surfaces or grooves  191  and exterior radially outwardly extending annularly segmented stop disk portions  194 . 
     Referring to  FIGS. 11 and 12 , the segmented stop disks  194  circumscribe and radially extend from an exterior of the medial arm portions of the plurality of circumferentially spaced apart upwardly extending collet arms  180  defining an annular segmented stop disk. 
     As illustrated in  FIG. 12 , each of the segmented stop disks  194  comprises a proximally or upwardly facing stop disk surface  198  and a distally or downwardly facing stop disk surfaces  196 . Additionally, the plurality of lower arm portions  186  comprise inner cylindrical or interior segmented surfaces  188  dimensioned with an inner diameter that closely circumscribes the spacer  160  which circumscribes the elongated central body member  102 . 
     The distal or lower end of the interior segmented surfaces  188  radially inwardly transition into the interior annular shoulder stop surface  177  that provide the stop surface for spacer  160  as detailed above. The proximal or upper end of the interior segmented surfaces  188  transition into the interior annular recessed segmented surface or groove  191 . 
     Upper Arm Portions  190   
     Referring to  FIGS. 11 and 12 , the plurality of circumferentially spaced apart upper arm portions  190  upwardly and radially outwardly transition from the respective lower arm portions  186  and terminate into a plurality of free ends  199  disposed above and radially outwardly from the lower arm portions  186  wherein the plurality of free ends  199  comprise radially outwardly projecting segments defining segmented collar  200  wherein each segment comprises an exterior outwardly facing surface  202  which, in in one embodiment is outwardly rounded or arcuate in shape corresponding to the arcuate groove of the example embodiment of the pipette tip. 
     Accordingly, the upper arm portions  190  upwardly and radially outwardly transition from the segmented stop disks  194  to a plurality of radially outwardly projecting segments defining segmented collar  200  wherein the segmented collar  200  is configured to circumscribe longitudinal central axis  90  of the expanding mandrel collet coupling device  100  as illustrated in  FIG. 7 . 
     Additionally, the plurality of circumferentially spaced apart radially outwardly and upwardly extending upper arm portions  190  including the segments respectively comprise interior surfaces  192  forming an inclined segmented interior surface complemental to the proximally inclined annular side surface  216  of the annular wedge  210  ( FIG. 7 ) wherein each comprises a distally decreasing circumference relative to the Z axis and wherein the interior surfaces  192  of the upper arm portions  190  form a radially outwardly and upwardly extending conically shaped gap  204  with respect to the elongated central body member  102  ( FIG. 15 ). 
     In particularly, and as illustrated in  FIG. 15 , the upwardly and radially outwardly inclined inner surfaces  192  of the plurality of circumferentially spaced apart upper arm portions  190  define a distally tapering cone gap  204  between the inner surfaces  192  of the upper arm portions  190  and the combination of the lower portion of the mounting flange  36  and the upper portion of spacer  160 . The tapering cone gap  204  is configured to receive the lower portion of annular wedge  210  such that the annular wedge shaped or inclined exterior side surface  216  of the annular wedge  210  abuts the inner surfaces  192  of the plurality of free ends  199  supporting the projecting segments defining segmented collar  200 . 
     Annular Wedge  210   
     Referring to  FIGS. 7, 13, and 15 , the annular wedge  210  comprises a resilient wedge shaped annular body having a circumferentially continuous, generally wedge shaped cross section  211 . The annular wedge  210  comprises a central interior annular surface  212  defining a central annular opening  213  extending through the annular wedge  210  configured to moveably circumscribe body  102 . 
     Additionally, the annular wedge  210  comprises a top planar circular surface  214  configured to make an electrical contact switch with the LLD circuit ring end  366  of the LLD circuit  364  and radially outwardly extending from the central interior annular surface  212  to a circumscribing outer edge surface  215 . 
     Furthermore, the annular wedge  210  comprises a radially outwardly proximally inclined side surface  216  radially upwardly and outwardly extending from a bottom annular end  218  to an underside of an annular peripheral lip  219  that radially extends outwardly and terminates to the circumscribing outer edge surface  215 . Accordingly, radially outwardly proximally inclined side surface  216  defines a distally tapering wedge surface  216 . 
     As illustrated in  FIG. 15 , the central annular opening  213  of the annular wedge  210  is dimensioned to allow passage of the distal mounting flange  36  and elongated tubular upper shank member  108  so as to allow a seating abutment of the radially outwardly proximally inclined side surface  216  of the annular wedge  210  with the inner surfaces  192  of the plurality of radially outwardly projecting segments  200  such that distal axial translation of annular wedge  210  results in the radial projection of the radially outwardly projecting segments  200  of the expanding mandrel collet  170  and subsequent proximal translation of annular wedge  210  results in the radial retraction of the radially outwardly projecting segments  200  of the expanding mandrel collet  170 . 
     As further illustrated in  FIG. 15 , the shank member  108  of the expanding mandrel collet coupling device  100  is configured to fit within the distal mounting flange  36  of the aspirating and dispensing cylinder  34  for operatively coupling the expanding mandrel collet coupling device  100  to the pipette device  20  of the pipette device assembly  10  such that the longitudinal channel axis  80  and longitudinal central axis  90  form a coincident or common axis. 
     The expanding collet  170  is further configured to radially outwardly expand the segmented collar  200  from an unexpanded state having a first circumference as generally illustrated in  FIG. 7  to an expanded state having a second circumference greater than the first circumference as generally illustrated in  FIG. 14  when, under a force provided by the squeeze sleeve  46 , the annular wedge  210  moves axially downwardly. 
     Actuation of Squeeze Motor 
     Referring to  FIG. 15 , the expanding mandrel collet coupling device  100  is configured to be fitted within the distal mounting flange  36  with the top planar circular surface  214  of the annular wedge  210  disposed adjacent the distal end  50  of the squeeze sleeve  46 . Accordingly, and referring to  FIGS. 4 and 15 , the actuation of the squeeze motor  52  in the first direction results in linear axial translation of the squeeze sleeve  46  in a distal or vertically downward direction for applying a force axially on top surface  214  of the annular wedge  210  resulting in the distally tapering wedge surface  216  axially sliding down further into the cone gap  204  for forcing the distally tapering wedge surface  216  against the interior surfaces  192  of the plurality of radially outwardly projecting segments  200  for pushing the exterior radially outwardly facing surfaces  202  ( FIG. 11 ) of the segments  200  radially outwardly against the spring tension of upwardly extending collet arms  180  and into contact with a first working surface of a pipette tip in the form of a surface  244  defining a groove  246  of the disposable pipette tip  220  as exemplified in  FIG. 29  described below. 
     Subsequent actuation of the squeeze motor  52  in the second direction, opposite the first direction, returns the distal end  50  of the squeeze sleeve  46  to a home position illustrated in  FIG. 15  such that the annular wedge member  210  axially slides up as a result the release of the stored potential energy in the upwardly extending collet arms  180  thereby resulting in the retraction of the exterior radially outwardly facing surfaces  202  of the plurality of radially outwardly projecting segments  200  from the groove  246  of the disposable pipette tip  220 . 
     Pipette Tip  220   
     As illustrated in  FIGS. 2 and 16 , and as noted above, the expanding mandrel collet coupling device  100  provides an open communication coupling between the disposable pipette tip  220  and the pipette device  20  of the pipette device assembly  10 . 
     Referring to  FIGS. 16 through 18 , and in one example embodiment, the disposable pipette tip  220  comprises an elongated tubular pipette tip body  222  having a central longitudinal axis  224 . Pipette tip body  222  comprises an elongated circumscribing sidewall  226  longitudinally extending along the central longitudinal axis  224  between a proximal or upper annular end face  228  and a distal or lower annular end face  230  defining circumscribing open proximal and distal annular ends  232  and  234  respectively. The elongated circumscribing sidewall  226  comprises an interior surface  236  defining a pipette tip passage opening  238  extending longitudinally along the central longitudinal axis  224  of the pipette tip body  222  between the open upper annular end  232  and the open lower annular end  234 . 
     Accordingly, the pipette tip passage opening  238  provides open communication from an area exterior to the open distal annular end  234  ( FIG. 18 ), through the pipette tip  220 , and to the pipette device channel  40  ( FIG. 15 ) by way of the central channel  136  of the expanding mandrel collet coupling device  100  ( FIG. 16 ) when the coupling device  100  is coupled between the pipette device  20  and the pipette tip  220 . In this coupling configuration, the central longitudinal axis  224  of the pipette tip body  222  is coextensive with the longitudinal channel axis  80  of the pipette device  20 . 
     In an alternate embodiment, the pipette tip passage opening  238  provides open communication from an area exterior to the open distal annular end  234  ( FIG. 18 ), through the pipette tip  220 , and to the pipette device channel  3040  ( FIG. 79 ) by way of the central channel  3136  of nozzle  3102  and the leaf spring coupling device  3100  ( FIG. 80 ) when the nozzle  3102  and the leaf spring coupling device  3100  are coupled between the pipette device  3020  and the pipette tip  220 . In this coupling configuration, the central longitudinal axis  224  ( FIG. 17 ) of the pipette tip body  222  is coextensive with the longitudinal channel axis  3080  of the pipette device  3020 . 
     First Interior Surface Section 
     Referring to  FIG. 18 , and in one example embodiment, the interior surface  236  of the elongated circumscribing sidewall  226  comprises an uppermost annular chamfered interior surface  240  that distally extends radially inward from the proximal annular end face  228  of the pipette tip  220  and terminates by transitioning into a first substantially cylindrical interior surface section  242  having a first diameter. 
     Axially Arcuate Circumferential Surface Defining a Groove 
     As illustrated in  FIG. 18 , and in one example embodiment, the first substantially cylindrical interior surface section  242  comprises an axially arcuate circumferential interior surface  244  formed into the elongated circumscribing sidewall  226  defining a circumferential annular groove  246 . Annular groove  246  divides the first substantially cylindrical interior surface section  242  into an upper first substantially cylindrical interior surface portion and a lower first substantially cylindrical interior surface portion of substantially equal diameter. Accordingly, the annular groove  246  provides a circumferential radially outwardly extending concave shaped interior surface interruption of the first substantially cylindrical interior surface section  242  with an arcuate surface longitudinal cross section. The arcuate circumferential interior surface  244  is also configured in alternative surface cross sections as discussed below. And in one embodiment, the first substantially cylindrical interior surface section  242  is devoid of arcuate circumferential interior surface  244  defining the circumferential annular groove  246 . 
     Referring to  FIGS. 18 and 19 , the axially arcuate circumferential interior surface  244  defining the annular groove  246  comprises an upper annular transition edge  248  distally transitioning into an upper axially arcuate circumferential surface sector portion  250  of the axially arcuate circumferential interior surface  244 . In succession, the upper axially arcuate circumferential surface sector portion  250  distally transitions into a lower axially arcuate circumferential surface sector portion  252  of the axially arcuate circumferential surface  244 . Then, lower axially arcuate circumferential surface sector portion  252  terminates to a lower annular transition edge  254 . 
     The upper axially arcuate circumferential surface sector portion or upper portion  250  provides the annular groove  246  with an increasing radius relative to the central longitudinal axis  224  ( FIG. 17 ) of the pipette tip  220  from the upper annular transition edge  248  to a maximum radius of the annular groove  246  relative to the central longitudinal axis  224  that defines a circumferential annular center of the annular groove  246 . The lower axially arcuate circumferential surface sector portion or lower portion  252  provides the annular groove  246  with a decreasing radius relative to the central longitudinal axis  224  of the pipette tip  220  from the maximum radius defining the circumferential annular center of the of the annular groove  246  to the lower annular transition edge  254 . 
     Second Interior Surface Section and Annular Shoulder Stop Surface 
     As illustrated in  FIG. 18 , the first substantially cylindrical interior surface section  242  is axially distally proceeded by a second substantially cylindrical interior surface section  262  having a second diameter less than the first diameter of the first substantially cylindrical interior surface section  242  for forming a proximally facing, radially inwardly extending annular shoulder seat surface or axial stop surface  260  interposed between the first and second substantially cylindrical interior surface sections  242 ,  262 . 
     In one example embodiment, the proximally facing axial stop surface  260  is substantially planar and generally perpendicular to the central longitudinal axis  224  of the pipette tip body  222  as illustrated in  FIG. 17 . 
     Third Interior Surface Section and Sealing Seat 
     As also illustrated in  FIGS. 18 and 19 , the second substantially cylindrical interior surface section  262  is axially distally proceeded by a third substantially cylindrical interior surface section  272  having a third diameter less than the second diameter of section  262 . 
     Interposed between the second section  262  and the third section  272  is a frustoconical annular sealing seat or stop surface  270  defining a circumferential radially inwardly angled and distally extending distal working surface  270 . The frustoconical annular sealing seat surface  270  comprises an upper annular sealing seat edge  266  defining an annular border between the second substantially cylindrical interior surface section  262  and the frustoconical annular sealing seat surface  270 . In addition, the frustoconical annular sealing seat surface  270  comprises a lower annular sealing seat edge  268  defining an annular border between the frustoconical annular sealing seat surface  270  and the third interior surface section  272  wherein a diameter of the upper annular sealing seat edge  266  is greater than a diameter of the lower annular sealing seat edge  268 . 
     Accordingly, the frustoconical annular sealing seat surface  270  defines the circumferential radially inwardly angled and distally extending second working surface or sealing seat surface  270  interposed between the second substantially cylindrical interior surface section  262  and the third substantially cylindrical interior surface section  272 . 
     As illustrated, the sealing seat surface  270  is disposed at an acute angle relative to the central longitudinal axis  224  wherein the acute angle defines an acute sealing seat surface angle relative to the central longitudinal axis  224  ( FIG. 17 ). In one embodiment, the preferred acute sealing seat surface angle relative to the central longitudinal axis  224  is about 15 degrees to about 35 degrees with a preferred angle of about twenty-five degrees. As illustrated in  FIG. 41 , the acute sealing seat surface angle of an alternative sealing seat surface  2270  relative to the central longitudinal axis  224  is about 90 degrees. 
     Lower Interior Surface Portion 
       FIG. 18  further illustrates that in succession to the third substantially cylindrical interior surface section  272  is a fourth interior surface section  274  that is distally followed by a fifth interior surface section  275 . 
     In one example embodiment, the fourth interior surface section  274  distally tapers or decreases in diameter from a distal annular end  276  of the third substantially cylindrical interior surface section  272  to a proximal annular end  278  of the fifth interior surface section  275 . In turn, the fifth interior surface section  275  distally tapers or decreases in diameter from the proximal annular end  278  of the fifth interior surface section  275  to the open distal annular end  234  of the pipette tip  220  that is intended for immersion. Additionally, and in one example embodiment, the fifth interior surface section  275  has a greater taper than the fourth interior surface section  274 . 
     External Longitudinal Ribs 
     Referring to  FIG. 17 , one example embodiment of the pipette tip  220  comprises a plurality of circumferential spaced apart longitudinally extending external ribs  280  disposed on the tubular pipette tip body  222  adjacent the periphery of the proximal annular end face  228  and longitudinally extending externally therefrom to an exterior area of the circumscribing sidewall  226  that is adjacent to the third substantially cylindrical interior surface section  272  as illustrated in  FIG. 18 . 
     In one example embodiment, the plurality of circumferential spaced apart longitudinally extending external ribs  280  may be utilized to provide support for the pipette tip  220  on or in a support surface  282  through which the pipette body  222  has passed via, for example, a support surface aperture opening  284 . One example embodiment of the support surface  282  can be in the form of, but not limited to, lab ware in the form of a tip rack as is known in the art, and informed by the present disclosure. 
     Automated Pipetting Workstation or System 
     Referring to  FIGS. 5 and 20 , and in one example of use and operation, one or more of the pipette device assemblies  10  is employed in an automated pipetting workstation or system  300  that generally provides, but is not limited to, programmed transfers of liquid between containers which comprises mounting and ejection processes of one or more disposable pipette tips  220  to the expanding mandrel collet coupling device  100  operatively carried by the pipette device  20  for carrying out, for example, the programmed transfers of liquid between containers. 
     In one example embodiment, the automated pipetting workstation  300  generally comprises a robotic gantry  302  that carries at least one pipette device assembly  10  vertically above a horizontally disposed workstation deck  304 . The pipette device assembly  10  can comprise a single channel pipetting head or a multi-channel pipetting head. 
     Additionally, the robotic gantry  302  typically provides two or three degrees of freedom wherein three degrees of freedom comprises longitudinal translation along an axis defining an X-axis, latitudinal translation along an axis defining a Y-axis, and vertical (up and down) translation along an axis defining a Z-axis so that the pipette device assembly  10  can move along the length (X-axis) and width (Y-axis) of the deck and vertically up and down (Z-axis) relative thereto. With two degrees of freedom, the robotic gantry is typically provided with the ability to translate the pipette device assembly  10  vertically and either longitudinally or laterally. 
     In one example embodiment, the automated pipetting workstation  300  further comprises a main controller  306 , a pipette axis controller  308 , and a power supply  310  that provides power for the main controller  306 , the pipette axis controller  308 , and the pipette device assembly  10 . 
     Additionally, and in one example embodiment, a computer/controller  320  can also be employed with the workstation  300  and communicate with the main controller  306  and the pipette axis controller  308  for controlling the robotic gantry  302  and pipette device assembly  10  including the associated process protocols of the pipette device assembly  10  such as the disposable pipette tip  220  attaching and ejection (coupling and decoupling) processes detailed below. 
     In one example embodiment, the computer/controller  320  typically comprises a processor device or central processing unit (CPU)  322 , a hardware read only memory device (ROM)  324 , a hardware main memory device (RAM)  326 , a hardware storage memory  328  comprising a non-transitory computer readable medium or memory  330  having an operating system  332  and software  334  such as user defined processes  336  for the pipette device assembly  10  stored thereby, a user display  338 , a user input device  340 , an input interface  342 , an output interface  344 , a communication interface device  346 , and a system bus  348  which comprises one or more conductor or communication paths that permit communication among the devices of the computer/controller  320 . Computer/controller  320  may also be operatively couple to LAN and/or server  350 . A power supply  352  provides power for the computer/controller  320 . 
     Examples of the above delineated automated pipetting workstation  300  including software are presently manufactured and sold by Hamilton Company, the assignee of the present patent application, located at 4970 Energy Way, Reno, Nev. 89502, United States of America. 
     Pipette Tip Pickup Process with Expanding Mandrel Collet Coupling Device 
       FIGS. 21 through 31  illustrate details of an example embodiment of successive stages of a pipette tip pickup process and, in particular, a method of securing attachment of the pipette tip  220  to the expanding mandrel collet coupling device  100  operatively carried by the pipette device  20 . As noted above, and in one example embodiment, the pipette tip  220  may be supported by a support surface  282 . 
     As illustrated in  FIG. 21 , the expanding mandrel collet coupling device  100  is connected to the pipette device  20 , and upon command, the coupling device  100  is positioned over the open proximal end  232  of the pipette tip  220  wherein each of their respective central longitudinal axis is aligned along the Z-axis. The eject sleeve  62  is in the eject position, the squeeze sleeve  46  is in the unsqueezed position, the expanding mandrel collet  170  is in the relaxed state, and the distal O-ring  140  is in the unsqueezed state. 
     Next,  FIG. 22  illustrates the expanding mandrel collet coupling device  100  being moved down along the Z-axis into the pipette tip  220  for lowering the distal, elastomeric carrying portion of the coupling device  100  to pass into the interior cylindrical proximal end portions of the pipette tip  220  to bring the distal O-ring  140  into contact with the annular sealing seat or stop surface  270  of the tip  220  while maintaining the distal O-ring  140  in the unsqueezed state and before the upwardly facing annular shoulder seat or stop surface  260  of the pipette tip  220  and the downwardly facing axial stop disk surface  196  of the stop disk  194  are mated. 
     Next,  FIG. 23  illustrates the coupling device  100  being further moved down along the Z-axis. Additionally, and referring to  FIGS. 23 through 25 , the squeeze sleeve  46  is moved down along the Z-axis and pushes against the LLD circuit ring end  366  which contacts with and pushes against the top surface  214  of the annular wedge  210  that surmounts the expanding mandrel collet  170  while maintaining the plurality of radially outwardly projecting segments  200  in the unexpanded state as detailed in  FIG. 24 , maintaining the distal O-ring  140  in the uncompressed state as detailed in  FIG. 25 , and before the stop surface  260  of the pipette tip  220  and the axial stop shoulder surface  196  of the stop disk  194  are mated such that a gap  298  is maintained between the stop surface  260  of the pipette tip  220  and the axial stop shoulder surface  196  of the stop disk  194  of the expanding mandrel collet  170  as detailed in  FIG. 23 . 
     Next,  FIG. 26  illustrates the squeeze sleeve  46  being moved further down along the Z-axis for pushing the annular wedge  210  against the interior surface  192  of the plurality of radially outwardly projecting segments  200  for pushing them radially outwardly out and abutting the exterior radially outwardly facing rounded surfaces  202  of the plurality of radially outwardly projecting segments  200  against the upper axially arcuate circumferential surface sector portion  250  of the groove  246  of the disposable pipette tip  220  as detailed in  FIG. 27  for starting the process of squeezing or pushing the plurality of radially outwardly projecting segments  200  into the groove  246  and initially into abutment with the upper axially arcuate circumferential surface sector portion  250  of the axially arcuate circumferential interior surface  244  defining the groove  246 . As illustrated in  FIG. 26 , the action of the plurality of radially outwardly projecting segments  200  extending or being projected into the groove  246  as detailed in  FIG. 27  causes an axial upward force that starts the process of pulling the pipette tip  220  up for starting a process of seating the annular shoulder seat surface  260  of the pipette tip  220  with the axial stop shoulder surface  196  of the stop disk  194  for closing the gap  298  ( FIG. 23 ) and compressing the distal O-ring  140  with the sealing seat or stop surface  270  of the tip  220  as detailed in  FIG. 28 . 
       FIG. 29  illustrates the squeeze sleeve  46  being moved down along the Z-axis a configured predetermined length until it is locked in position resulting in the annular wedge  210  being stopped and locked in position by the squeeze sleeve  46 . 
     As a result, the plurality of radially outwardly projecting segments  200  are radially extended to a desired distance or value as exemplified in  FIG. 30  for fully seating the axial stop shoulder surface  196  of the expanding mandrel collet coupling device  100  against the annular shoulder seat surface  260  of the pipette tip  220  with the seating of the two surfaces  196 ,  260  being along an X-axis substantially perpendicular to the Z-axis for forming a normal datum between the two axes. 
     Concurrently, the distal O-ring  140  is compressed to a desired distance or value as exemplified in  FIG. 31  for seating the distal O-ring  140  with the annular sealing seat surface  270  of the tip  220  such that its cross-section is in its final compressed non-circular form thereby completing the coupling of securing the attachment of the pipette tip  220  with the expanding mandrel collet coupling device  100  operatively carried by the pipette device  20 . 
     Upon completion of the above detailed securing attachment process, the plurality of radially outwardly projecting segments  200  and the distal elastomeric element  140  work in combination to produce a segment and seal coupling that provides a fluid-tight seal wherein the plurality of radially outwardly projecting segments  200  are at least partially received within the circumferential groove  246  and at least partially seated on the circumferential arcuate interior surface  244  ( FIG. 18 ) defining the circumferential groove  246  and wherein the distal elastomeric element  140  seals against the surface  270  of the pipette tip  220  wherein in one embodiment surface  270  provides a radially inwardly angled and distally or downwardly extending surface. 
     Accordingly, the plurality of radially outwardly projecting segments  200  move radially outward to engage the circumferential groove  246  ( FIG. 18 ) to couple with the tip  220  and move radially inward for releasing the tip  220  as a function of movement of the annular wedge  210 . Applying a force for moving the annular wedge  210  axially downwards results in the plurality of radially outwardly projecting segments  200  being urged to a radially outward position and releasing the force on the annular wedge  210  results in a release of energy from the cantilevered arms  180  ( FIG. 11 ) supporting the plurality of radially outwardly projecting segments  200  such that the segments spring back from the radially outward position to the radially inward position. 
     Disposable Pipette Tip Ejection Process 
       FIGS. 21 through 31  illustrate, in reverse, details of successive stages of an example method or process of ejecting the pipette tip  220  from the expanding mandrel collet coupling device  100  operatively carried by the pipette device  20 . This tip ejection process sequence is similar to the attachment or tip pickup securing process sequence except in reverse and  FIG. 34  illustrates a distal O-ring axial force component of the compressed distal O-ring  140  that provides a force to help remove the tip  220  during the ejection process. 
     In one example embodiment, the ejection process comprises the steps of: (1) positioning the tip where it is to be discarded, such as a waste container; (2) moving the squeeze sleeve  46  upward wherein force is released from the annular wedge  210  and, as a result, this force is also released from the plurality of radially outwardly projecting segments  200  so as to allow retraction from the groove  246  in the tip  220 , the distal O-ring  140  starts to release stored elastic potential energy or spring energy as a force against the tip  220 , and wherein the spring loaded eject sleeve  62  also pushes against the tip  220  to push it off such that the tip begins to release from the plurality of radially outwardly projecting segments  200 ; (3) continuing the movement of the squeeze sleeve  46  upward wherein the plurality of radially outwardly projecting segments  200  continue to retract from the groove  246  in the tip  220  and wherein the distal O-ring  140  and the spring loaded eject sleeve  62  pushes against the tip  220  to push it off wherein the tip  220  continues to release from the plurality of radially outwardly projecting segments  200 ; and (4) further continuing the movement of the squeeze sleeve  46  to its upmost position wherein the plurality of radially outwardly projecting segments  200  return to their original retracted free state and are completely free of the groove  246  in the tip  220  and wherein the distal O-ring  140  returns to its original shape and the spring loaded eject sleeve  62  pushes against the tip  220  until the tip is pushed off of the coupler  100  by the spring loaded eject sleeve  62  and the spring loaded eject sleeve  62  becomes fully extended. 
     In light of the foregoing, those skilled in the art will appreciate that these tip mounting and ejection processes are applicable to a wide range of mechanically and/or automatically driven pipette types and designs. 
     Coupling and Ejection Forces 
       FIG. 32  illustrates a diagrammatical vector diagram of a plurality of radially outwardly projecting segments  200  of the expanding mandrel collet coupling device  100  initially extending into the groove  246  with radially rounded surface  202  of the plurality of radially outwardly projecting segments  200  contacting the upper corner of the tip groove above the center of the segment radius resulting in an axial upward force pulling the pipette tip  220  upward. As illustrated in  FIG. 32 , the segment force (Fsegment_resultant) for each of the plurality of radially outwardly projecting segments  200  is comprised of two components: an axial force (Fsegment_axial) component and a radial force (Fsegment_radial) component. 
     As long as the plurality of radially outwardly projecting segments  200  are contacting the upper corner of the tip groove above the center of the segment radius (dimension Z in  FIG. 33 ) Fsegment_axial increases as the distance between the center of the segment radius and corner of the groove increases. Accordingly, at the beginning of the tip pickup process, the segment axial force (Fsegment_axial) starts out low as illustrated in  FIG. 32  and, in detail in  FIG. 33 , and increases to its maximum at the end of the tip pickup process as illustrated in  FIG. 34 . 
     Referring to  FIG. 33 , the ratio of Z/R equals SIN (w) and SIN (w) is equal to (Fsegment_axial)/(Fsegment_resultant). As a result, (Fsegment_axial) is equal to (Fsegment_resultant) multiplied by the ratio of Z/R. From this, the result is that (Fsegment_axial) increases as Z increases. 
     Referring to  FIG. 34 , the segment axial force (Fsegment_axial) seats the stop disc  194  against the seat  260  of the tip  220  and provides the force required to overcome an O-ring axial force (Fdistal_ring_axial) and compress the distal O-ring  140 . The O-ring  140  has an O-ring force (Fdistal_ring_resultant) that results from being compressed and this O-ring force comprises two components: an axial component (Fdistal_ring_axial) and a radial component (Fdistal_ring_radial). Additionally, the segment radial force (Fsegment_radial) provides the radial force needed to lock the segment into the tip groove  246  ( FIG. 18 ) and the distal O-ring radial force component (Fdistal_ring_radial) provides the radial force needed to maintain the seal against the tip. Furthermore, the segment to tip groove geometry that causes Fsegment_axial to increase as the segment enters the groove (increasing dimension Z) helps to overcome the O-ring axial force (Fdistal_ring_axial) so that the distal O-ring  140  can be completely compressed to the desired extent. Moreover, the distal O-ring axial force component (Fdistal_ring_axial) provides force to help remove the tip  220  during the ejection process. 
     Alignment/Misalignment 
     The axial shoulder surface  196  of coupler  100  and the axial shoulder seat  260  of tip  220  are important for correct tip alignment. Accordingly, the coupler  100  and tip  220  are configured so that plurality of radially outwardly projecting segments  200  push the axial shoulder surface  196  and the axial shoulder seat  260  together to preclude misalignment because if the shoulders are not properly mated, especially if they are tilted, the misalignment error (E) may be significant. 
     For example, and as illustrated in  FIGS. 35 and 36 , the relationship between the misalignment angle (Ø), the tip axial distance (D) and positional error (E) is: E=D*TAN (Ø). For example, with a misalignment angle (Ø) of two degrees and a tip axial distance of ninety millimeters, the positional error (E) is 3.14 millimeters. This is considered to be very high considering typical positional error tolerances are typically plus or minus 0.5 millimeters. 
       FIG. 37  illustrates correct tip alignment with the axial shoulder surface  196  and the axial shoulder seat  260  in flush contact with one another to provide proper alignment and to maintain the tip axial distance D from the tip seat  260  to the distal end  230  constant to establish a known and controlled distance of the pipette tip end  230  along the vertical or axial axis Z and a perpendicular axis X. This is important to allow the pipette device to target small holes and small volumes of liquid. Additionally, smaller volumes of liquid can be transferred resulting from the known fixed distance of the pipette tip allowing for a controlled touch of the pipette tip/liquid to the working surface  290  onto or from which liquid  292  is to be transferred. 
     Dimensions and Relationships 
     Accordingly, for proper use and operation, dimensions between the coupler  100  and tip  220  are related accordingly. 
     Referring to  FIGS. 15, 38, and 39 , the tip groove diameter A must be large enough to allow the segments  200  to pull the tip  220  up and adequately lock the tip  220  in place. Conversely, if it is too big, the segments  200  may not be able to be pushed in sufficiently to get a good lock. Additionally, internal diameters B and C must be larger than external diameter K of stop disc  194  and external diameter L of annular base  172 , respectively. However, they must not be too much bigger, as this may result in a poor fit and/or misalignment. 
     Referring to  FIGS. 38 and 39 , the tip seat to groove dimension S must be matched to the stop disk seat surface  196  to segment  200  center dimension M. This relationship is critical to the coupling between the tip  220  and stop disc  194 . 
     Referring to  FIGS. 19, 38, and 39 , the dimension of the tip seat surface  260  to the O-ring seal land  266  in  FIG. 19 , dimension F in  FIG. 38 , must match the stop disk surface  196  to the distally facing perpendicular lip surface  171 , dimension N in  FIG. 39 . These dimensions control the amount that the distal O-ring  140  is compressed, and thus how well it seals. The tip surface  260  and stop disc seating/coupling surface  196  must be fully mated in order to provide proper alignment and maintain the tip axial distance D. 
     Referring to  FIGS. 37 through 39 , the dimension D between the tip seat  260  to the distal end  230  (or axial distance) along with the mating of the coupling seats establish a known and controlled distance of the pipette tip end. This is important to allow the pipette device to target small holes and small volumes of liquid. Additionally, smaller volumes of liquid can be transferred resulting from the known fixed distance of the pipette tip allowing for a controlled touch of the pipette tip/liquid to the working surface onto or from which liquid is to be transferred. 
     Referring to  FIGS. 15, 38, and 39 , the tip internal diameter G must be smaller than diameter L of base  172  in order to create a seat or land for the distal O-ring  140  to seal against. If diameter G is too large, then the distal O-ring may not seal well. If the diameter is too small, then the distal O-ring  140  may not fully compress and may prevent the stop disc  194  from seating, or may cause harm to the distal O-ring  140 . Additionally, the ramp length H along with the diameter G control the seat or land that mates with the O-ring  140 . These dimensions are critical in providing a good O-ring seal. If ramp length H is too long, then the O-ring may not seal well. If H is too short, then the O-ring may not fully compress and may prevent the stop disc  194  from seating, or may cause harm to the O-ring  140 . 
     Liquid Level Detection (LLD) Circuit Contacts 
     Referring to  FIG. 40 , and in one example embodiment, the pipette device assembly  10  further comprises a liquid level detection circuit assembly. The liquid level detection circuit assembly comprises a liquid level detection or LLD circuit board  360  comprising processing circuitry  362  electrically coupled to a LLD circuit contact  364  operatively coupled to the squeeze sleeve  46  that is made from an electrically non-conducting material so it is insulated from the rest of the assembly and wherein the contact  364  terminates to a circuit contact ring end  366  recessed in the bottom area of the squeeze sleeve  46  that is configured for selectively contacting the circuit contact ring end  366  with annular wedge  210  between the non-contact state illustrated in  FIG. 22  and the contact state illustrated in  FIG. 29  and therefore in contact with the plurality of conductive segments or elements coupling with the interior first working surface of a conductive tip  220 . 
     As illustrated in  FIG. 29 , the LLD circuit contact  364  comprises the ring end  366  captured between the squeeze sleeve  46  and the annular wedge  210  wherein electrical closure or contact is made between the processing circuitry  362  of the LLD circuit board  360  ( FIG. 40 ) and the annular wedge  210  which is made from electrically conductive material. The annular wedge  210  pushes and makes electrical contact with the plurality of radially outwardly projecting segments  200  which are made using an electrically conductive nonpliable material. 
     Accordingly, with the tip attached and the plurality of radially outwardly projecting segments  200  squeezed or pushed and locked into the tip groove  246  of the tip  220 , the plurality of radially outwardly projecting segments  200  make electrical contact with the tip  220  which is also made from an electrically conductive material. As a result, and referring to  FIG. 40 , this completes the circuit between the processing circuitry  362  of the LLD circuit board  360  and the tip  220 . 
     Additionally, the stop disk mounting post or distal mounting flange  36  is formed from a non-conducting material. Therefore, the body member  102  and the plurality of radially outwardly projecting segments  200  are insulated from the rest of the assembly. 
     Furthermore, the processing circuitry  362  of the LLD circuit board  360  detects a signal change when the tip  220  contacts liquid thereby having an ability to detect a surface of a liquid being transferred or a surface onto or from which liquid is being transferred. Again, actuation occurs when the coupling device  100  is attached to the tip  220  and the plurality of radially outwardly projecting segments  200  are radially pushed circumferentially and locked into the tip groove of the tip  220 . 
     Alternative Example Embodiments 
       FIG. 41  illustrates the example embodiment of the expanding mandrel collet coupling device  100  positioned over the example embodiment of the disposable pipette tip  220  comprising an alternative sealing seat surface  2270  having an angle of substantially ninety degrees relative to the central longitudinal Z axis of the pipette tip  220 . 
       FIG. 42  illustrates the example embodiment of the expanding mandrel collet coupling device  100  positioned in the disposable pipette tip comprising the alternative sealing seat surface  2270  wherein the tip  220  is lifted up to its final seated state and the annular wedge  210  moved into its final position for defining the final coupling state with the distal elastomeric element  140  in the final compressed and seated sealing state against the alternative sealing seat surface  2270 . 
       FIG. 43  details the final compressed state of the distal elastomeric element  140  against the alternative sealing seat surface  2270 . 
       FIG. 44  illustrates the upper interior of the disposable pipette tip  220  comprising another alternative sealing seat surface in the form of a circumferential radially concave sealing seat surface  3270 .  FIG. 45  details the circumferential radially concave sealing seat surface  3270  illustrated in  FIG. 44 . 
       FIG. 46  illustrates the example embodiment of the disposable pipette tip  220  illustrating detail of a further alternative sealing seat surface in the form of a circumferential radially convex sealing seat surface  4270 .  FIG. 47  details the circumferential radially convex sealing seat surface  4270  illustrated in  FIG. 46 . 
       FIG. 48  illustrates the example embodiment of the disposable pipette tip  220  illustrating a yet further alternative sealing seat surface in the form of a circumferential upward facing tooth edge sealing seat surface  5270 .  FIG. 49  details the circumferential upward facing tooth edge sealing seat surface illustrated in  FIG. 48 . 
       FIG. 50  is a fragmentary, longitudinal sectional, side elevational view of the example embodiment of the expanding mandrel collet coupling device  100  positioned over the example embodiment of the disposable pipette tip  220  comprising an alternative V-shaped groove  2246  defined by an V-shaped circumferential interior surface  2244  of the disposable pipette tip  220  opening toward the longitudinal Z axis and having a V-shaped cross section as illustrated. 
       FIG. 51  illustrates the expanding mandrel collet coupling device  100  being positioned in the disposable pipette tip  220  comprising the alternative V-shaped groove  2246  ( FIG. 50 ) wherein the tip  220  is lifted up to its final state with the rounded surfaces  202  of the plurality of expanding mandrel collet segments  200  being extended into the V-shaped groove  2246  and into abutment against the V-shaped circumferential interior surface with the distal elastomeric element  140  in the final compressed and seated sealing state against the sealing seat surface  270  of the tip. 
       FIG. 52  illustrates the rounded surface  202  of one of the plurality of expanding mandrel collet segments  200  being extended into the V-shaped groove  2246  and abutting against the V-shaped circumferential interior surface  2244  defining the V-shaped groove  2246 . 
       FIG. 53  illustrates the example embodiment of the expanding mandrel collet coupling device positioned over a second example embodiment of a disposable pipette tip  1220  devoid of arcuate circumferential interior surface  244  defining the circumferential annular groove  246 . 
       FIG. 54  details the interior of the second example embodiment of the disposable pipette tip  1220  which is analogous in all portions with the exception that interrupted interior surface section  242  of the first substantially cylindrical interior surface section  242  illustrated in  FIG. 18  is devoid of interruption thereby defining uninterrupted interior surface section  1242  of the disposable pipette tip  1220  wherein the interior surface section  1242  defines the first working surface. 
       FIG. 55  illustrates the example embodiment of the expanding mandrel collet coupling device  100  positioned in the second example embodiment of the disposable pipette tip  1220  with the stop disk shoulder surface  196  of the coupling device  100  abutting against an axial stop surface  260  of the second example embodiment of the disposable pipette tip  1220  and the rounded surfaces  202  of the plurality of expanding mandrel collet segments  200  being extended against the interior surface  1242  of the circumscribing sidewall of the second example embodiment of the disposable pipette tip  1220  resulting in a deformation  1244  of the interior surface  1242  and with the distal elastomeric element  140  in the final compressed and seated sealing state against the sealing seat surface  270  of the second example embodiment of the disposable pipette tip  1220 . 
       FIG. 56  details the rounded surface  202  of one of the plurality of expanding mandrel collet segments  200  of the expanding mandrel collet coupling device  100  being extended against and deforming  1244  the interior surface  1242  of the circumscribing sidewall of the second example embodiment of the disposable pipette tip as is illustrated in  FIG. 55 . 
       FIGS. 57 through 67  are fragmentary, longitudinal sectional, side elevational views of the example embodiment of the disposable pipette tip comprising alternative groove shape embodiments relative to the circumferential annular tip groove for segments  200  illustrated in at least  FIG. 19  and the V-shaped groove segments  200  illustrated in at least  FIG. 50 . 
     In particular,  FIGS. 57 through 67  illustrate respective alternative groove configurations  2251  through  2261  for receipt of segments  200 . 
     Alternative Example Embodiment Collet  2170   
       FIG. 68  illustrates a second or alternative example embodiment of an expanding mandrel collet  2170  which is configured as a direct alternative to the expanding mandrel collet  170  ( FIG. 5 ) of the expanding mandrel collet coupling device  100  ( FIG. 5 ). The expanding mandrel collet  2170  is analogous in function to collet  170 , but configured to improve performance and longevity. 
     Referring to  FIGS. 68 and 69 , the expanding mandrel collet  2170  comprises a plurality of circumferentially spaced apart upwardly extending collet arms  2180  that radially outwardly extend and arcuately transition upwardly from the lower annular base portion  2172  and terminating to free segmented ends  2200  defining the segmented collar disposed axially above the lower annular base portion  2172 . The plurality of circumferentially spaced apart upwardly extending collet arms  2180  are separated from one another by one of a plurality of circumferentially spaced apart upwardly extending kerfs or slots  2182 . 
     Referring to  FIGS. 68 and 69 , each of the plurality of upwardly extending collet arms  2180  comprises a respective lower arm portion  2186  transitioning into a respective upper arm portion  2190 . In one embodiment, the plurality of circumferentially spaced apart lower arm portions  2186  form a circumscribing lower body portion  2181  and the plurality of circumferentially spaced apart upper arm portions  2190  form a frustoconically shaped circumscribing upper body portion  2183  radially outwardly and upwardly transitioning from the lower body portion  2181 . 
     Referring to  FIGS. 68 and 69 , the distal or lower annular base portion  2172  comprises a distally or downwardly facing base surface  2171 . The distally facing base surface  2171  downwardly transitions into an abbreviated distal or lower end annular stem surface  2174  that terminates to a distal or lower annular base portion end  2176  of the lower annular base portion  2172 . The base surface  2171  and lower end annular stem surface  2174  define an abbreviated distal end annular groove. 
     As illustrated in  FIG. 69 , the lower annular base portion  2172  further comprises an inner cylindrical surface  2175  upwardly transitioning into the interior annular shoulder stop surface  2177 . 
     As further illustrated in  FIG. 69 , the lower arm portions  2186  comprise the circumferentially spaced apart lower end portions  2184  that are attached to the lower annular base portion  2172 . The lower arm portions  2186  further comprise upper end portions defining medial arm portions having interior annular recessed segmented surfaces or grooves  2191  and exterior radially outwardly extending annularly segmented stop disk portions  2194 . The segmented stop disks  2194  circumscribe and radially extend from an exterior of the medial arm portions of the plurality of circumferentially spaced apart upwardly extending collet arms  2180  defining an annular segmented stop disk. Each of the segmented stop disks  2194  comprises a proximally or upwardly facing stop disk surface  2198  and a distally or downwardly facing stop disk surfaces  2196 . Additionally, the plurality of lower arm portions  2186  comprise inner cylindrical or interior segmented surfaces  2188  dimensioned with an inner diameter that closely circumscribes the spacer  160  ( FIG. 10 ) which circumscribes the elongated central body member  102  ( FIG. 10 ). 
     Referring to  FIGS. 68 and 69 , the plurality of circumferentially spaced apart upper arm portions  2190  upwardly and radially outwardly transition from the respective lower arm portions  2186  and terminate into a plurality of free ends  2199  disposed above and radially outwardly from the lower arm portions  2186  wherein the plurality of free ends  2199  comprise radially outwardly projecting segments defining segmented collar  2200  wherein each segment comprises an exterior outwardly facing surface  2202  which, in one embodiment is outwardly rounded or arcuate in shape. Accordingly, the upper arm portions  2190  upwardly and radially outwardly transition from the segmented stop disks  2194  to a plurality of radially outwardly projecting segments defining segmented collar  2200 . Additionally, the plurality of circumferentially spaced apart radially outwardly and upwardly extending upper arm portions  2190  including the segments respectively comprise interior surfaces  2192  forming an inclined segmented interior surface complemental to the proximally inclined annular side surface  216  ( FIG. 13 ) of the annular wedge  210  ( FIG. 13 ). 
     Comparing  FIGS. 12 and 69 , the expanding mandrel collet  2170  widens the base of each of the ends  2184  of each of the respective arms  2180  relative to the expanding mandrel collet  170  and radially extends the ends  2184  of arms  2180  outward in order to increase the radius of each of the arms  2180  relative to the expanding mandrel collet  170 . Pushing the lower ends outward and increasing their diameter allows a larger chord segment or width at the bottom ends  2184  of each of extending arms  2180  wherein the increased width of each of extending arms  2180  improves the strength of each of extending arms  2180 . Additionally, increasing radial extension at the lower ends  2184  of arms  2180  provides increased strength. The coupling function is unchanged. 
     From an engineering perspective, the extending arms  2180  can be modelled as a cantilever beam in bending. Classical strength of materials techniques can be used to evaluate material stress when the beam is subject to bending, as occurs when the coupler is engaged and disengaged. In addition, when bending is done repeatedly, or cyclically, the material stress can be analyzed with regard to fatigue strength to provide adequate product life. Increasing the width at the base of the beam, as well as increasing associated radii, are geometry modifications used to lower stress and improve strength. 
     Device Aspects 
     In one aspect, the pipette tip coupling device or expanding mandrel collet coupling device  100  provides improved life span. 
     In another aspect, the radially outwardly projecting segments  200  of the expanding mandrel collet  170  provide a more rigid coupling for providing a stiffer joint between the pipette tip  220  and coupler  100 . 
     In another aspect, the radially outwardly projecting segments  200  of the expanding mandrel collet  170  pulls the tip  220  up and seats it efficiently. 
     In another aspect, the coupler  100  will not be affected by ejecting a tip in free air. O-ring coupling life is adversely affected when the tip is ejected in free air because the O-ring is scuffed and abraded by the groove in the tip as the tip is pushed off by the spring loaded eject sleeve. The hardness of the radially outwardly projecting segments  200  resists the harmful acts of this scuffing and abrasion. 
     In another aspect, the material of the expanding mandrel collet  170  can easily be made from conductive material in order to provide an electrical circuit to the tip for liquid level detection or other uses as detailed above. 
     In another aspect, the radially outwardly projecting segments  200  of the expanding mandrel collet  170  are formed from hard and durable materials such as, but not limited to, metallic or hard plastic to provide improved life and because the discrete elements or segments are much harder than the plastic tip, they work into the tip groove more efficiently than soft elastomeric material such as an O-ring. 
     In another aspect, the radially outwardly projecting segments  200  can be activated with a low squeeze/axial force because the mechanical design is efficient. A lower squeeze/axial force requirement improves the life on the associated parts providing the axial force. As a result of this lower squeeze/axial force requirement, the radially outwardly projecting segments  200  allows the lower or distal seal  140  to have improved life span because the elastomeric material in not compressed as much. 
     In another aspect, the coupler  100  allows the lower or distal seal  140  to be easily accessed if replacement is required. Also, the lower or distal seal  140  can be made from a greater variety of materials because it does not need to be conductive for the LLD circuit. 
     In another aspect, maintenance costs are lower because of the improved life and easier accessibility to the lower or distal seal. 
     In yet another aspect, tip alignment to the pipette device  20  is improved because of improved seating. 
     Method Aspects 
     In light of the above, and in a further aspect, an example embodiment of a method is provided for securing attachment of at least one pipette tip to at least one pipette tip coupler in the form of an expanding mandrel collet coupling device carried by a pipette device, the method comprising: (1) providing a pipette tip comprising a sidewall having an interior circumscribing surface defining a passage opening extending between an open distal end intended for immersion in a medium to be pipetted and an open proximal end opposite in an axial direction to the open distal end; (2) providing a pipette tip coupler comprising a distally facing axial stop shoulder surface formed by an axially stepped coupler shoulder of an exterior circumscribing surface of the pipette tip coupler, the distally facing axial stop shoulder surface complementary to a proximally facing axial stop surface formed by an axially stepped shoulder surface of the interior circumscribing surface of the sidewall of the pipette tip; (3) providing a plurality of discrete coupling elements or segments spaced apart and disposed circumferentially on said upper seating surface of said pipette tip coupler body; (4) providing a distal elastomeric element carried by the pipette tip coupler at a location inferior to the axially stepped coupler shoulder; (5) locating a distal end of the pipette tip coupler over the open proximal end of the pipette tip with an axial alignment between a central longitudinal axis of the pipette tip coupler and a central longitudinal axis of the pipette tip; (6) translating the distal end of the pipette tip coupler through the open proximal end of the pipette tip until the distal elastomeric element contacts a circumferential radially inwardly angled and distally extending interior working surface of the interior circumscribing surface of the sidewall of the pipette tip distal from the axially stepped shoulder of the interior circumscribing surface of the sidewall of the pipette tip; and (7) axially squeezing or pushing the plurality of discrete coupling elements or segments into a radially extended state of abutment with an upper axially arcuate circumferential surface sector portion of an axially arcuate circumferential interior surface defining a groove formed into the interior circumscribing surface of the sidewall of the pipette tip at a location superior to the axial stop surface of the pipette tip for providing a proximally directed radial and axial resultant pre-stress force to the pipette tip for energizing the distal elastomeric element into a compressed state configured for providing the axial and radial sealing abutment of the outer circumferential portion of the distal elastomeric element with the circumferential radially inwardly angled and distally extending interior working surface of the interior circumscribing surface of the sidewall of the pipette tip, and for abutting the proximally facing axial stop surface of the pipette tip with the distally facing axial stop surface of said pipette tip coupler body to define an axial coupling position of the pipette tip on the pipette tip coupler device. 
     In light of the present disclosure as set forth above, further structural modifications and adaptations may be resorted to without departing from the scope and fair meaning of the embodiments of the present disclosure as set forth above. For example,  FIGS. 57 through 67  are fragmentary, longitudinal sectional, side elevational views detailing different alternative example embodiments to the circumferential annular tip groove  246  illustrated in at least in  FIG. 19  and the V-shaped groove segments  200  illustrated in at least  FIG. 50 . In particular,  FIGS. 57 through 67  illustrate respective alternative groove configurations  2251  through  2261  for receipt of segments  200 . Additionally, the segments of the coupler may comprise radially outwardly faces complementary to the respective different alternative example embodiments of the respective groove configurations  2251  through  2261 . Accordingly, the first working surface is in the form of, but not limited to, the respective groove configurations or the uninterrupted configuration illustrated in  FIGS. 53-56  wherein the first substantially cylindrical interior surface section  242  is devoid of interruption thereby defining uninterrupted interior surface section  1242  of the disposable pipette tip  1220 . Furthermore, the tip distal O-ring sealing seat  270  may have different geometries in the form of, but not limited to, flat conical, concave radius, convex radius, step, et cetera. Moreover, the distal O-ring may have alternate shapes than an O-ring and may be in the form of, but not limited to, configurations complementary to the tip distal O-ring sealing seat  270 . 
     INDUSTRIAL APPLICABILITY 
     The above delineation of the systems, assemblies, devices, and methods including uses and operations, demonstrate the industrial applicability of embodiment(s) of the present disclosure. 
     Accordingly, it should be apparent that further numerous structural modifications and adaptations may be resorted to without departing from the scope and fair meaning of the embodiment(s) of the present disclosure as set forth hereinabove and as described hereinbelow by the claims. Hence, the spirit and scope of the appended claims should not be limited to the above delineated description of the embodiment(s) of the present disclosure. And, in the appended claims reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present disclosure, for it to be encompassed by the present claims. 
     Alternate Pipette Device Assembly  3010   
       FIGS. 70 through 75  illustrate an alternate example embodiment of a pipette device assembly  3010  comprising an example embodiment of a pipette device  3020 , an example embodiment of a nozzle  3102 , and an example embodiment of a leaf spring coupling device  3100  or pipette tip coupler for use with a disposable pipette tip  220  that is removably coupled to the pipette device  3020  by way of the nozzle  3102  and the leaf spring coupling device  3100 . 
     Pipette Device  3020   
     Referring to  FIGS. 71 and 72 , the pipette device  3020  comprises a body  3022  supporting an aspirating and dispensing device  3024  comprising a plunger  3026  operatively coupled to and driven by a motor  3028 . The plunger  3026  resides within a plunger cylinder  3030  extending from a distal or lower end  3032  of the body  3022  of the pipette device  3020 . 
     Pipette device  3020  further comprises an aspirating and dispensing cylinder  3034  that is at least partially disposed within plunger cylinder  3030  at a location axially aligned with and distally below the plunger  3026 . Plunger cylinder  3030  distally transitions into a distal mounting flange  3036  for attaching nozzle  3102 . The leaf spring coupling device  3100  couples at one end with the nozzle  3102  and the leaf spring coupling device  3100  removably couples at the other end with the disposable pipette tip  220 . 
     Referring to  FIGS. 70, 71, 72, 77, and 79 , nozzle  3102  comprises an aspirating and dispensing cylinder  3034 . The aspirating and dispensing cylinder  3034  further comprises an interior circumscribing sidewall  3038  that defines an open ended pipette channel  3040  extending therethrough. The open ended pipette channel  3040  longitudinally extends along a longitudinal channel axis  3080  of the pipette device assembly  3010  between an open upper end portion  3042  and open lower end portion  3044  of the aspirating and dispensing cylinder  3034  for providing open communication between plunger  3026  and an exterior area adjacent to distal mounting flange  3036 . The distal mounting flange  3036  is operatively connected to a nozzle  3102  which in turn is connected to the leaf spring coupling device  3100 . An open ended central channel  3136  extends through the nozzle  3102  and leaf spring coupling device  3100  to provide open communication between the tip  220  and the aspirating and dispensing cylinder  3034 . 
     Plunger Carriage  3063  and Eject Sleeve  3062   
     Referring to  FIGS. 70 through 74 , the aspirating and dispensing device  3024  comprises a lead screw  3067 , which is driven by a motor  3028 . A lead nut  3054  is operatively connected to the lead screw  3067 . In one embodiment, the lead nut  3054  is threaded and screwed onto the lead screw  3067 . A plunger carriage  3063  circumscribes and is operatively connected to the lead nut  3054  such that motion of the motor  3028  drives the lead nut  3054  which in turn drives the plunger carriage  3063  parallel to the longitudinal channel axis  3080 . 
     An eject block  3065  circumscribes lead screw  3067  and is located below the plunger carriage  3063 . An eject rod  3069  is operatively connected to the end of the eject block  3065 . The eject rod  3069  extends from the eject block  3065  through the distal or lower end  3032  of the body  3022  of the pipette device  3020  via a passageway  3021 . An eject spring  3074  circumscribes the eject rod  3069 . The eject spring  3074  is located between the distal end of the eject rod  3065  and the distal or lower end  3032  of the body  3022  of the pipette device  3020  such that the spring force acts in the direction to push the eject block  3065  away from the plunger carriage  3063 . 
     The pipette device further comprises an eject sleeve  3062  which circumscribes the plunger cylinder  3030  and nozzle  3102  and contains the aspirating and dispensing cylinder  3034 . Eject sleeve  3062  is used to eject the disposable pipette tip  220  from the pipette device  3020  wherein the ejection sleeve  3062  is axially movable relative to the aspirating and dispensing cylinder  3034  and plunger cylinder  3030  and comprises a proximal or upper end  3064 , a distal or lower end  3066 , and an ejection sleeve arm  3068  attached at a first end to the ejection sleeve  3062  adjacent to the upper end  3064  and having an opposing second end removably attached to a distal end  3071  of the eject rod  3069 . 
     The eject sleeve  3062  is in the free state when no pipette tip  220  is mounted, such as after a pipette tip  220  has been ejected. To mount a pipette tip  220 , the ejection sleeve spring force must be overcome in order to axially push the ejection sleeve  3062  to a retracted state as illustrated in  FIGS. 71 through 73 . Furthermore, the spring  3074  is dimensioned to be sufficiently long such that it provides a force to assist in ejecting the pipette tip  220  until the pipette tip  220  is completely decoupled from the leaf spring coupling device  3100 . 
     Nozzle  3102  and Leaf Spring Coupling Device  3100   
       FIGS. 74 through 75  illustrate nozzle  3102  and leaf spring coupling device  3100  which are used to mount pipette tip  220  to pipette device  3020 . 
     Nozzle  3102   
     More specifically, the nozzle  3102  comprises a nozzle mounting portion  3103  located at a top end of the nozzle  3102 , a nozzle stem portion  3107  located at a bottom end of the nozzle  3102  relative to the nozzle mounting portion, nozzle body portion  3105  located between the nozzle mounting portion  3103  and the nozzle stem portion  3107 , and a nozzle elastomeric element  3135 . Nozzle mounting portion  3103  connects nozzle  3102  to distal mounting flange  3036  ( FIGS. 71 and 79 ) of pipette device  3020 . 
     As further illustrated in  FIGS. 75 and 79 , the nozzle  3102  further comprises nozzle elastomeric element  3135  coaxially carried around the nozzle stem portion  3107  of nozzle  3102 . The nozzle stem portion  3107  is located at the opposite end relative to the longitudinal central axis  3090  of nozzle  3102  from the nozzle mounting portion  3103 . In an example embodiment, the nozzle stem portion  3107  further comprises a nozzle groove  3109  and the nozzle elastomeric element is carried within the nozzle groove  3109 . In an example embodiment, the nozzle elastomeric element  3135  is an O-ring. 
     Leaf Spring Coupling Device  3100   
     As illustrated in  FIGS. 74 through 77 , the leaf spring coupling device  3100  comprises a coupling cylinder  3173 , a leaf spring cylinder  3175 , a distal stem base  3121 , and a distal or lower elastomeric element  3140  carried at the distal stem base  3121 . 
     As illustrated in  FIGS. 76 and 77 , the lower end  3171  of the coupling cylinder  3173  is connected to a leaf spring cylinder  3175 . The leaf spring assembly  3170  is formed in the leaf spring cylinder  3175 . The upper annular stop shoulder end  3177  of the leaf spring cylinder  3175  is located at the lower end of the leaf spring assembly  3170 . The lower portion  3122  of the leaf spring cylinder  3175  and is connected to the distal stem base  3121 . 
     As also illustrated in  FIGS. 76 and 77  the distal stem base  3121  comprises a the distal cylindrical stem portion surface  3124  that transitions from upper annular stop shoulder end  3122  into a round end plate  3126  having an upper surface  3128  and a lower surface defined by the distal or lower annular end face  3130 . As illustrated, the end plate  3126  has a diameter greater than a diameter of the narrowest portion of the distal cylindrical stem portion surface  3124  wherein the distal stem portion surface  3124  defines a distal groove portion  3132  of the leaf spring coupling device  3100 . When a pipette tip  220  is coupled with leaf spring coupling device  3100 , the upper annular stop shoulder end  3177  will abut the proximally facing axial stop surface  260  of pipette tip  220  to prevent the leaf spring coupling device  3100  from being inserted too far into pipette tip  220 . 
     Distal Elastomeric Element  3140   
     As further illustrated in  FIGS. 76 and 77 , the leaf spring coupling device  3100  further comprises the distal or lower elastomeric element  3140  coaxially carried at the distal stem portion  3124 . When a pipette tip  220  is coupled to the leaf spring coupling device  3100 , the distal elastomeric element  3140  serves as a seal. 
     In one embodiment, and referring to  FIGS. 77 and 78 , the distal elastomeric element  3140  comprises an annular body  3142 . Annular body  3142  comprises an interior surface  3144  defining a central opening  3146 , a top surface  3148 , a peripheral exterior surface  3150 , and a bottom surface  3152 . Central opening  3146  is dimensioned to closely or tightly circumscribe the distal stem portion  3124  of the leaf spring coupling device  3100  while shaped to reside within groove  3132  and extend radially outwardly circumferentially beyond end plate  3126  as illustrated in  FIG. 76 . In a relaxed or unsqueezed state, the distal elastomeric element  3140  comprises a circumferentially continuous, generally circular cross section area  3154  as is illustrated in  FIG. 79 . 
     Leaf Spring Assembly  3170   
     Referring to  FIGS. 76, 77 and 82 , the leaf spring assembly  3170  comprises a plurality of circumferentially spaced apart leaf springs  3180  formed in the leaf spring cylinder  3175  and arranged parallel to the longitudinal central axis  3090  and separated by open vertical slots  3182 . Leaf springs  3180  are flexible. Each pair of adjacent leaf springs  3180  are separated by an open vertical slot  3182 . The leaf springs  3180  are flexible and are used to retain a pipette tip on the leaf spring coupling device  3100 . 
     Each leaf spring  3180  comprises a retention bump  3202  that protrudes from the exterior surface  3185  of the leaf spring  3180 . In one embodiment, each of the plurality of retention bumps  3202  has a rounded surface protruding from the exterior surface  3185 . When a pipette tip is coupled to the leaf spring coupling device  3100 , the plurality of retention bumps  3202  on the leaf spring assembly  3170  expand into the groove  246  of pipette tip  220  to hold, or retain, the pipette tip  220  on the leaf spring coupling device  3100 . 
     Each leaf spring  3180  further comprises a stabilizer plateau  3183  that protrudes from the exterior surface  3185  of the leaf spring  3180 . When a pipette tip is coupled to the leaf spring coupling device  3100 , the plurality of stabilizer plateaus  3183  on the leaf spring assembly  3170  prevent the pipette tip from rocking. The plurality of stabilizer plateaus  3183  prevent the tip from rotating on the leaf spring coupler  3100  about the retention bumps  3202  that are positioned within the groove  246  of pipette tip  220 . Such rocking or rotation contributes to misalignment between the end of the pipette tip  220  and the longitudinal central axis  3090 . Further, this type of rocking could disengage the pipette tip seal if a side load is applied. To prevent this problem, in one embodiment, the plurality of stabilizer plateaus  3183  are placed on each leaf spring  3180  above, or closer to the coupling cylinder  3173  relative to, the retention bumps  3202 . The plurality of stabilizer plateaus  3183  have an interference fit with the pipette tip  220  when the retention bumps  3202  have expanded into the groove  246  of the pipette tip  220 . The plurality of stabilizer plateaus  3183  adds another point of contact between the pipette tip  220  and the leaf spring coupling device  3100  to prevent the tip from rocking. 
     Pipette Tip Pickup Process with the Leaf Spring Coupling Device  3100   
       FIGS. 81-85  illustrate details of an example embodiment of successive stages of a pipette tip pickup process and, in particular, a method of securing attachment of the pipette tip  220  to the leaf spring coupling device  3100  operatively carried by the pipette device  3020 . As noted above, in an example embodiment, the pipette tip  220  may be supported by a support surface  282 . 
     As illustrated in  FIGS. 73, 77, and 81 , the leaf spring coupling device  3100  is connected to device  3020  via nozzle  3102 , and upon command, the leaf spring coupling device  3100  is positioned over the open proximal end  232  of the pipette tip  220  wherein each of their respective central longitudinal axis is aligned along the Z-axis. The leaf springs  3180  are in the relaxed state. The eject sleeve spring  3074  has pushed eject block  3065  and the eject sleeve  3062  to the lowest position. Plunger carriage  3063  is positioned up to allow eject block  3065  to move up during the pipette tip pickup process. The distal elastomeric element  3140  is in the unsqueezed state. 
     Next,  FIGS. 73, 76, 82, 83, and 84  illustrates the leaf spring coupling device  3100  being moved down along the Z-axis ( FIG. 81 ) into the pipette tip  220  for lowering the distal elastomeric carrying portion of the leaf spring coupling device  3100  to pass into the interior cylindrical proximal end portions of the pipette tip  220  to bring the distal elastomeric element  3140  into contact with the annular sealing seat  270  of the pipette tip  200  while maintaining the distal elastomeric element  3140  in the unsqueezed state. The leaf springs  3180  have entered the pipette tip  220  and are in the compressed state. The pipette tip pushes the eject sleeve  3062  and eject block  3065  up. At this point, there is a gap  3298  between the axial stop surface  260  of the pipette tip  220  and the upper annular stop shoulder end  3177  of the leaf spring coupling device  3100  as detailed in  FIG. 82 . Additionally, and referring to  FIGS. 81 and 82 , it is shown that the retention bumps  3202  are beginning to move into the groove  246  of the pipette tip  220 . 
     Next,  FIGS. 77 and 85  illustrate the leaf spring coupling device  3100  being further moved down along the Z-axis into the pipette tip  220  until the leaf spring coupling device  3100  seats firmly against the sealing seat  270  of pipette tip  220 . The retention bumps  3202  on the leaf springs  3180  have reached and snapped into the groove  246  on the pipette tip  220  to lock the pipette tip into place on the leaf spring coupling device  3100 . The distal elastomeric element  3140  has compressed against the sealing seat  270  in the pipette tip  220 . The stabilizer plateaus are engaged with the tip to prevent the pipette tip from rotating on the leaf spring coupling device  3100 . 
     Upon completion of the above detailed securing attachment process, the plurality of leaf springs  3180  and the distal elastomeric element  3140  work in combination to produce a segment and seal coupling that provides a fluid-tight seal wherein the plurality of retention bumps  3202  are at least partially received within the groove  246  of the pipette tip  220  and at least partially seated on the circumferential arcuate interior surface  244  ( FIG. 18 ) defining the groove  246  of the pipette tip and wherein the distal elastomeric element  3140  seals against the sealing seat  270  that provides a radially inwardly angled and distally or downwardly extending surface. 
     Disposable Pipette Tip Ejection Process with the Leaf Spring Coupling Device  3100   
       FIGS. 81-85  illustrate, in reverse, details of successive stages of an example method or process of ejecting the pipette tip  220  from the leaf spring coupling device  3100  operatively carried by the pipette device  3020 . This tip ejection process sequence is similar to the attachment or tip pickup securing process sequence except in reverse. 
     As illustrated in  FIGS. 72, 73, and 81-85 , in one example embodiment, the ejection process includes rotating the lead screw  3067  so the plunger carriage  3063  is driven downward into the eject block  3065 . The eject block  3065  pushes the eject sleeve  3062  downward via its attachment to the eject rod  3069 . The eject sleeve  3062  starts pushing the pipette tip  220  off the leaf spring coupling device  3100 . The pipette tip  220  does not start to move until the force is great enough that the leaf springs  3180  ( FIG. 77 ) compress to allow the retention bumps  3202  to move out of the groove  246  in the pipette tip  220 . 
     Next, the leaf springs  3180  have fully compressed within the pipette tip  220 . The pipette tip  220  is no longer vertically retained to the leaf spring coupling device  3100 . At this point in the ejection process, the distal elastomeric element  3140  has lost contact with the sealing seat  270  and thus the seal has been broken. The plunger carriage  3063  continues to drive the eject sleeve  3062  down and pushes the pipette tip  220  off of the leaf spring coupling device  3100 . 
     Next, the pipette tip  220  continues to be driven off the leaf spring coupling device  3100 . The retention bumps  3202  reach the opening of the pipette tip  220  and the leaf springs  3180  start expanding toward the relaxed state. 
     At the completion of the ejection process, the pipette tip  220  has lost contact with leaf spring coupling device  3100 . The leaf springs  3180  are in the relaxed state. The eject sleeve spring  3074  has pushed the eject block  3065 , and the eject sleeve  3062  is in the lowest position. After the pipette tip  220  has been ejected, the plunger carriage  3063  is positioned up to allow the eject block  3065  space to move up during the next pipette tip pickup process. 
     Coupling and Ejection Forces for the Leaf Spring Coupling Device  3100   
       FIG. 86  illustrates a diagrammatical vector diagram of a plurality of retention bumps  3202  of the leaf spring coupling device  3100  initially extending into the groove  246  with retention bumps  3202  on the leaf springs  3180  contacting the upper corner of the tip groove  246  above the center of the retention bump radius resulting in an axial upward force pulling the pipette tip  220  upward. As illustrated in  FIG. 86 , the retention bump force, or segment force, (Fsegment_resultant) for each of the plurality of retention bumps  3202  is comprised of two components: an axial force (Fsegment_axial) component and a radial force (Fsegment_radial) component. 
     As long as the plurality of retention bumps  3202  are contacting the upper corner of the tip groove  246  above the center of the retention bump radius (dimension Z in  FIG. 87 ) Fsegment_axial increases as the distance between the center of the retention bump radius and corner of the groove  246  increases. Accordingly, at the beginning of the pipette tip pickup process, the segment axial force (Fsegment_axial) starts out low as illustrated in  FIG. 86  and, in detail in  FIG. 87 , and increases to its maximum at the end of the pipette tip pickup process as illustrated in  FIG. 88 . 
     Referring to  FIG. 87 , the ratio of Z/R equals SIN (ω) and SIN (ω) is equal to (Fsegment_axial)/(Fsegment_resultant). As a result, (Fsegment_axial) is equal to (Fsegment_resultant) multiplied by the ratio of Z/R. From this, the result is that (Fsegment_axial) increases as Z increases. 
     Referring to  FIG. 88 , the segment axial force (Fsegment_axial) seats the upper annular stop shoulder end  3177  against the axial stop surface  260  of the pipette tip  220  and provides the force required to overcome an O-ring, or distal elastomeric, axial force (Fdistal_ring_axial) and compress the distal elastomeric element, or O-ring,  3140 . The O-ring  3140  has an O-ring force (Fdistal_ring_resultant) that results from being compressed and this O-ring force comprises two components: an axial component (Fdistal_ring_axial) and a radial component (Fdistal_ring_radial). Additionally, the segment radial force (Fsegment_radial) provides the radial force needed to lock the retention bump  3202  into the tip groove  246  ( FIG. 18 ) and the distal O-ring radial force component (Fdistal_ring_radial) provides the radial force needed to maintain the seal against the pipette tip  220 . Furthermore, the retention bump to tip groove geometry that causes Fsegment_axial to increase as the retention bump  3202  enters the groove  246  (increasing dimension Z) helps to overcome the O-ring axial force (Fdistal_ring_axial) so that the distal O-ring  3140  can be completely compressed to the desired extent. Moreover, the distal O-ring axial force component (Fdistal_ring_axial) provides force to help remove the tip  220  during the ejection process. 
     Alignment/Misalignment for the Leaf Spring Coupling Device  3100   
     The upper annular stop shoulder end  3177  of coupler  3100  and the axial stop surface  260  of tip  220  are important for correct tip alignment. Accordingly, the leaf spring coupling device  3100  and pipette tip  220  are configured so that plurality of retention bumps  3202  push the upper annular stop shoulder end  3177  and the axial stop surface  260  together to preclude misalignment because if the upper annular stop shoulder end  3177  and the axial stop surface  260  are not properly mated, especially if they are tilted, the misalignment error (E), which is the same as that illustrated for the embodiment shown in  FIG. 36 , may be significant. 
     Dimensions and Relationships for the Leaf Spring Coupling Device  3100   
     Accordingly, for proper use and operation, dimensions between the leaf spring coupling device  3100  and tip  220  are related. 
     Referring to  FIGS. 38, 79, and 85 , the tip groove diameter A must be large enough to allow the retention bumps  3202  to pull the tip  220  up and adequately lock the tip  220  in place. Conversely, if the tip groove diameter A is too large, the retention bumps  3202  may not be able to be pushed in sufficiently to get a good lock. Additionally, internal diameters B and C must be larger than external diameter K of upper annular stop shoulder end  3177  and external diameter L, respectively. However, they must not be too much larger, as this may result in a poor fit and/or misalignment. 
     Referring to  FIGS. 38 and 85 , the tip seat to groove dimension S must be matched to the upper annular stop shoulder end  3177  to segment  200  center dimension M. This relationship is critical to the coupling between the tip  220  and upper annular stop shoulder end  3177 . 
     Referring to  FIGS. 19, 38, and 85 , the dimension of the axial stop surface  260  to the O-ring seal land  266  in  FIG. 19 , dimension F in  FIG. 38 , must match the upper annular stop shoulder end  3177  to the distally facing perpendicular lip surface  3179 , dimension N in  FIG. 85 . These dimensions control the amount that the distal O-ring  3140  is compressed, and thus how well it seals. The axial stop surface  260  and upper annular stop shoulder end  3177  must be fully mated in order to provide proper alignment and maintain the tip axial distance D. 
     Referring to  FIGS. 38 and 85 , the dimension D between the axial stop surface  260  to the distal end  230  (or axial distance) establish a known and controlled distance of the pipette tip end. This is important to allow the pipette device to target small holes and small volumes of liquid. Additionally, smaller volumes of liquid can be transferred resulting from the known fixed distance of the pipette tip allowing for a controlled touch of the pipette tip/liquid to the working surface onto or from which liquid is to be transferred. 
     Referring to  FIGS. 38, 79, and 85 , the tip internal diameter G must be smaller than diameter L of the leaf spring coupling device in order to create a seat or land for the distal O-ring  3140  to seal against. If diameter G is too large, then the distal O-ring may not seal well. If the diameter is too small, then the distal O-ring  3140  may not fully compress and may prevent upper annular stop shoulder end  3177  from seating, or may cause harm to the distal O-ring  3140 . Additionally, the ramp length H along with the diameter G control the seat or land that mates with the O-ring  3140 . These dimensions are critical in providing a good O-ring seal. If ramp length H is too long, then the O-ring may not seal well. If H is too short, then the O-ring may not fully compress and may prevent the upper annular stop shoulder end  3177  from seating, or may cause harm to the O-ring  3140 . 
     Liquid Level Detection 
     Pipette device assembly  3010  further comprises a liquid level detection circuit assembly as described for the pipette device assembly  10  ( FIG. 40 ). In an example embodiment, the material of the nozzle  3102  and the leaf spring coupling device  3100  can easily be made from conductive material to provide an electrical circuit to the pipette tip  220  for liquid level detection or other uses as detailed above with respect to pipette device assembly  10 . 
     Alternative Example Embodiments 
       FIG. 90  illustrates the example embodiment of the leaf spring coupling device  3100  positioned in the disposable pipette tip comprising the alternative sealing seat surface  2270  wherein the tip  220  is lifted up to its final seated state with the distal elastomeric element  3140  in the final compressed and seated sealing state against the alternative sealing seat surface  2270 . 
       FIG. 91  details the final compressed state of the distal elastomeric element  3140  against the alternative sealing seat surface  2270 .