Patent Publication Number: US-2023133990-A1

Title: Pipette-tip connecting device and method thereof

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an automation equipment for biology and chemistry laboratories, especially to a device that is adapted for connecting a pipette-tip to a pipette. 
     2. Description of the Prior Arts 
     A pipette is a laboratory tool for precisely drawing up a measured volume of liquid and dispensing the liquid into other containers. The pipette is used in conjunction with at least one pipette-tip. A cylindrical tip connector (male part) is located at bottom of the pipette. Top of the pipette-tip is hollow and cylindrical to form a mount opening (female part). When in use, the mount opening of pipette-tip is tightly located around the tip connector and the pipette-tip is in actual contact with the liquid. 
     The pipette-tip is disposable and requires frequent replacement to avoid contamination in case the residual liquid in the pipette tip has any chance to contact another sample. To replace the pipette-tip, first use an ejector mechanism of the pipette to eject the pipette-tip from the tip connector, and then align and insert the tip connector into a new pipette-tip via the mount opening. 
     To ensure that the pipette-tip can be tightly located around the tip connector, an outer diameter of the tip connector is very close to an inner diameter of the mount opening of the pipette-tip, and therefore an axis of the tip connector must be accurately aligned with an axis of the pipette-tip before insertion. When the pipette-tip replacement is manually operated, alignment between the tip connector and the pipette-tip can be achieved correctly through vision and hand feeling. 
     However, a standard automation apparatus is only capable of moving the pipette along a fixed path, meaning that there is no feedback correction for aligning the tip connector with the pipette-tip, and therefore it is difficult to automate the process of pipette-tip replacement because the replacement will fail as long as there is a slight deviation of the connection path between the tip connector and the pipette-tip, and in reality it is difficult to prevent such deviation. As a result, currently the replacement of pipette-tip can only be manually operated, which is time-consuming and requires more labor. 
     To overcome the shortcomings, the present invention provides a pipette-tip connecting device and method thereof to mitigate or obviate the aforementioned problems. 
     SUMMARY OF THE INVENTION 
     The main objective of the present invention is to provide a pipette-tip connecting device and method thereof that allow the replacement process of pipette-tip to be automated. 
     In order to achieve the above objective, the present invention provides a pipette-tip connecting device which comprises a base, a first positioning mechanism, a second positioning mechanism, a connecting seat, a pipette-fixing seat, and a tilt actuator. The first positioning mechanism is mounted on the base and extends along a first direction. The first positioning mechanism has a first slider and a first actuator. The first slider is slidable along the first direction. The first actuator controls a position of the first slider along the first direction. The second positioning mechanism is linked to the first slider and extends upward and downward along a second direction. The second positioning mechanism has a second slider and a second actuator. The second slider is slidable upward and downward along the second direction. The second actuator controls a position of the second slider along the second direction. The connecting seat is mounted on the second slider. The pipette-fixing seat is mounted on the connecting seat and is pivotable relative to the connecting seat around an imaginary pivoting axis. The pipette-fixing seat has a pipette-fixing portion which moves in the first direction and the second direction when the pipette-fixing seat pivots relative to the connecting seat. The tilt actuator is mounted on the connecting seat and controls a relative angle between the pipette-fixing seat and the connecting seat. The tilt actuator is electrically connected to the first actuator and the second actuator. 
     When in use, pipette-tips are located under the pipette-fixing seat with mount openings thereof facing upward. Meanwhile, a pipette is fixed to the pipette-fixing seat with the tip connectors directed downward, and the alignment of tip connectors are substantially parallel to the alignment of the pipette-tips at this moment. A corner of the tip connector where a distal end surface and an annular surface thereof are connected forms two right angles when viewed laterally. Then, the tilt actuator tilts the pipette such that centerlines of the tip connectors are tilted relative to centerlines of the pipette-tips to direct one of said two right angles of each of the tip connectors toward the mount opening of a respective one of the pipette-tips. The first actuator locates one of the right angles on top of the mount opening, and then the second actuator moves the pipette downward to insert said right angle into the pipette-tip via the mount opening, wherein the annular surface of the tip connector can abut against a periphery of the mount opening to guide the insertion. 
     After the right corner of the tip connector is inserted, the tilt actuator gradually realigns the centerlines of the tip connectors to match with the centerlines of the pipette-tips, and meanwhile the first actuator and the second actuator compensate deviation of the tip connectors due to angle adjustment. When the tip connectors are realigned and connect primarily with the pipette-tips, the second actuator presses down the pipette such that the tip connectors are firmly connected to the pipette-tips. 
     In order to achieve the above objective, the present invention further provides a pipette-tip connecting method which comprises several steps as follows: 
     (a) Preparation for tip replacement: Fix a pipette to a pipette-fixing seat. At least one cylindrical tip connector protrudes from a bottom of the pipette. A first actuator controls a position of the pipette-fixing seat along a first direction. A second actuator controls upward and downward movement of the pipette-fixing seat. A tilt actuator controls an angle of the pipette-fixing seat. Prepare at least one pipette-tip which extends upward and downward. Each of the at least one pipette-tip has a mount opening formed on a top thereof. 
     (b) Tilted insertion: The tilt actuator tilts the pipette such that a centerline of each of the at least one tip connector is tilted relative to a centerline of each of the at least one pipette-tip. The first actuator aligns a distal end of each of the at least one tip connector to the mount opening of a respective one of the at least one pipette-tip, and then the second actuator moves the pipette downward such that the distal end of each of the at least one tip connector is partially inserted into the respective one of the at least one pipette-tip via the mount opening. 
     (c) Straightened pressing down: The tilt actuator, the first actuator, and the second actuator control the pipette such that the pipette is rotated with the at least one tip connector as center of rotation to align the centerline of each of the at least one tip connector and match with the centerline of the respective one of the at least one pipette-tip, and primarily insert the at least one tip connector into the pipette-tip. Then, the second actuator presses down the pipette such that each of the at least one tip connector is tightly fitted in the respective one of the at least one pipette-tip. 
     The advantage of the present invention is that the tilt actuator is configured to control tilting of the tip connectors relative to the pipette-tips such that the tip connectors of the pipette can be inserted in a tilted manner to make the correct connection with the pipette-tips more easily; that is, when viewed laterally, the tip connectors can be successfully inserted into the mount opening respectively as long as the corners are located between the widths of the mount openings. There is no need to align the corners and match with the centers of the mount openings precisely, thereby greatly reducing need of positioning accuracy by manual work and making automation of repeating the connection the pipette A with new pipet-tips possible. Production speed and labor need are therefore reduced significantly. 
     Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of a pipette-tip connecting device in accordance with the present invention; 
         FIG.  2    is an exploded perspective view of the pipette-tip connecting device in  FIG.  1   ; 
         FIG.  3    is a partial exploded perspective view of the pipette-tip connecting device in  FIG.  1   ; 
         FIG.  4    is a top view of the pipette-tip connecting device in  FIG.  1   ; 
         FIG.  5    is an enlarged schematic side view of the pipette-tip connecting device in  FIG.  1   ; 
         FIG.  6    is an enlarged operational side view of the pipette-tip connecting device in  FIG.  1   , showing a centerline of the pipette being tilted relative to a centerline of the pipette-tip; 
         FIG.  7    is an enlarged operational side view of the pipette-tip connecting device in  FIG.  1   , showing the pipette moved downward and the tip connector inserted into the pipette-tip via a mount opening; 
         FIG.  8    is an enlarged operational side view of the pipette-tip connecting device in  FIG.  1   , showing the pipette rotated with the tip connectors as center of rotation to realign the tip connectors with the pipette-tips; 
         FIG.  9    is an enlarged operational side view of the pipette-tip connecting device in  FIG.  1   , showing the tip connectors aligned with the pipette-tips and fully inserted into the pipette-tips; 
         FIG.  10    is an enlarged operational side view of the pipette-tip connecting device in  FIG.  1   , showing the pipette moved upward with the pipette-tips connected to the tip connectors; and 
         FIG.  11    is a flow chart of a pipette-tip connecting method in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to  FIG.  1   , a pipette-tip connecting device in accordance with the present invention is configured to connect pipette-tips B to tip connectors A 1  in a bottom of a pipette A. The tip connectors A 1  are preferably cylindrical. The pipette A may have only one tip connector A 1 . Multiple unused pipette-tips B are orderly arranged in a box. The pipette-tips B extend upwards and downwards, and each of the pipette-tips B has a mount opening formed on top thereof. 
     With reference to  FIGS.  1 ,  2 , and  4   , the pipette-tip connecting device has a base  10 , a first positioning mechanism  20 , a second positioning mechanism  30 , a connecting seat  40 , a pipette-fixing seat  50 , and a tilt actuator  60 . In the preferred embodiment, the pipette-tip connecting device further has a linkage mechanism  70  and a third positioning mechanism  80 . 
     The first positioning mechanism  20  is mounted on the base  10  and extends along a first direction D 1 . The first direction D 1  is preferably horizontal. The first positioning mechanism  20  has a first slider  21  and a first actuator  22 . The first slider  21  is slidable along the first direction D 1 . The first actuator  22  controls a position of the first slider  21  along the first direction D 1 . To be precise, the first positioning mechanism  20  is a horizontally mounted linear module. The first actuator  22  is a motor controlling the first slider  21  via a ball screw of the first positioning mechanism  20 . 
     The second positioning mechanism  30  is linked to the first slider  21  such that the first positioning mechanism  20  controls a position of the second positioning mechanism  30  along the first direction D 1 . In the preferred embodiment, the third positioning mechanism  80  is mounted between the first slider  21  of the first positioning mechanism  20  and the second positioning mechanism  30 ; that is, the second positioning mechanism  30  is linked to the first slider  21  via the third positioning mechanism  80 . 
     The third positioning mechanism  80  extends along a third direction D 3  and has a third slider  81  and a third actuator  82 . The third slider  81  is movable along the third direction D 3  such that the second positioning mechanism  30  can be aligned with other experiment equipment. In another preferred embodiment, the second positioning mechanism  30  is omitted, and the second positioning mechanism  30  is directly mounted on the first slider  21 . 
     With reference to  FIG.  5   , the second positioning mechanism  30  extends upward and downward along a second direction D 2 . The second direction D 2  is preferably vertical, but can be slightly tilted relative to the vertical line. The second positioning mechanism  30  has a second slider  31  and a second actuator  32 . The second slider  31  is slidable upward and downward along the second direction D 2 . The second actuator  32  controls the position of the second slider  31  along the second direction D 2 . The second actuator  32  is preferably a linear module. 
     With reference to  FIGS.  3 ,  5 , and  6   , the connecting seat  40  is mounted on the second slider  31  such that the first positioning mechanism  20  and the second positioning mechanism  30  control a position of the connecting seat  40  along the first direction D 1  and the second direction D 2 . 
     The pipette-fixing seat  50  is mounted on the connecting seat  40  and is pivotal relative to the connecting seat  40  around an imaginary pivoting axis L 1 . The pipette-fixing seat  50  has a pipette-driving end  51  and a pipette-fixing portion  52 . The pipette-fixing portion  52  is configured to fix the pipette A. The pipette-fixing portion  52  moves in the first direction D 1  and the second direction D 2  when the pipette-fixing seat  50  pivots relative to the connecting seat  40 . In other words, when the pipette-fixing seat  50  pivots, the pipette-fixing portion  52  moves along a circular path around the pivoting axis L 1  such that movement of the pipette-fixing portion  52  has component in the first direction D 1  and the second direction D 2 . 
     The pivoting axis L 1  is nonparallel to the first direction D 1  and the second direction D 2 , and to be precise, the pivoting axis L 1  is perpendicular to the first direction D 1  and second direction D 2 . The pipette-driving end  51  is located above the pivoting axis L 1 . 
     The tilt actuator  60  is mounted on the connecting seat  40  and controls a relative angle between the pipette-fixing seat  50  and the connecting seat  40 . In the preferred embodiment, the tilt actuator  60  is a linear actuator and has a main body  61  and a driving rod  62 . The main body  61  is mounted on the connecting seat  40 . The driving rod  62  is linearly movably mounted in the main body  61 . Linear movement of the driving rod  62  controls the relative angle between the pipette-fixing seat  50  and the connecting seat  40 . 
     The tilt actuator  60  is electrically connected to the first actuator  22  and the second actuator  32  such that when the pipette-fixing seat  50  is being tilted by the tilt actuator  60 , the position of the connecting seat  40  in the first direction D 1  and the second direction D 2  is dynamically compensated by the first actuator  22  and the second actuator  32  to substantially maintain the tip connector A 1  of the pipette A in a fixed position. 
     The linkage mechanism  70  connects the tilt actuator  60  and the pipette-fixing seat  50  to transform linear motion of the driving rod  62  into rotary motion of the pipette-fixing seat  50 . The linkage mechanism  70  has a connecting block  71 , a connecting bar  72 , a guiding seat  73  and a guiding slider  74 . 
     The connecting block  71  is fixed to the driving rod  62  of the tilt actuator  60 . Two opposite ends of the connecting bar  72  are a first end and a second end respectively. The first end is pivotally connected to the connecting block  71 , and the second end is pivotally connected to the pipette-driving end  51  of the pipette-fixing seat  50 . A relative angle between the connecting bar  72  and the driving rod  62  is preferably from 40 to 60 degrees to ensure that the linear motion of the driving rod  62  can be stably and precisely transformed into the rotary motion of the pipette-fixing seat  50 . 
     The guiding seat  73  is fixed on the main body  61  of the tilt actuator  60 . The guiding slider  74  is mounted on the guiding seat  73  and is capable of moving in parallel direction with the driving rod  62 . The guiding slider  74  is disposed along with the driving rod  62  of the tilt actuator  60 . The guiding slider  74  is fixed to the connecting block  71  such that when the connecting block  71  is moved by the force of the driving rod  62  and the guiding slider  74  to reduce the angle between the connecting block  71  and the connecting bar  72 . 
     The tilt actuator  60  is not limited to be connected to the pipette-fixing seat  50  via the linkage mechanism  70 . In another preferred embodiment, the tilt actuator  60  has an output end that controls rotary motion, and said output end is directly connected to the pipette-fixing seat  50  to change the angle between the pipette-fixing seat  50  and the connecting seat  40 , and then is able to control the tilting angle of pipette A 
     With reference to  FIG.  11   , a pipette-tip connecting method in accordance to the present invention comprises the following steps: the first step (S 1 ) is preparation for tip replacement; the second step (S 2 ) is tilted insertion; the third step (S 3 ) is straightened pressing down. The pipette-tip connecting method is performed by, but not limited to, the aforementioned pipette-tip connecting device. 
     The first step (S 1 ) is preparation for tip replacement. With reference to  FIG.  5   , fix the pipette A to the pipette-fixing seat  50 . The cylindrical tip connectors A 1  of the pipette A are protruded from a bottom of the pipette A as aforementioned. The first actuator  22  controls the position of the pipette-fixing seat  50  along the first direction D 1 . The second actuator  32  controls upward and downward movement of the pipette-fixing seat  50 ; that is, the second actuator  32  controls the movement of the pipette-fixing seat  50  along the second direction D 2 . The tilt actuator  60  controls the angle of the pipette-fixing seat  50 . Prepare the pipette-tips B for replacement. The pipette-tips B extend upward and downward. Each one of the pipette-tips B has the mount opening formed on the top thereof. 
     The second step (S 2 ) is tilted insertion. With reference to  FIG.  6    and  FIG.  7   , the tilt actuator  60  tilts the pipette A such that the centerlines L 2  of the tip connectors A 1  are tilted relative to the centerlines L 3  of the pipette-tips B as shown in  FIG.  6   . The first actuator  22  aligns distal ends of the tip connectors A 1  to the mount openings of the pipette-tips B. To be precise, the first actuator  22  aligns a corner A 12  of each one of the tip connectors A 1  above the mount opening of a corresponding one of the pipette-tips B, wherein said corner A 12  is the portion of a distal end surface A 11  and the pipette-tips B are connected primarily. When viewed laterally as shown in  FIG.  5   , the corner A 12  forms two right angles. 
     Then, the second actuator  32  moves the pipette A downward such that the corners A 12  of the tip connectors A 1  are able to insert into the pipette-tips via the mount opening and then the second actuator moves continually the pipette downward such that the distal end of the at least one pipette-tip is partially inserted into the pipette-tips B via the mount openings. 
     The third step (S 3 ) is straightened pressing down. With reference to  FIGS.  7  to  9   , the tilt actuator  60 , the first actuator  22 , and the second actuator  32  control the pipette A such that the pipette A is rotated with the tip connectors A 1  as center of rotation to align the centerlines L 2  of each of the tip connectors A 1  and match with the centerline L 3  of the respective one of the pipette-tips B and to fully insert the distal end surfaces A 11  of the tip connectors A 1  into the pipette-tips B respectively. Finally, the second actuator  32  presses down the pipette A such that each of the tip connectors A 1  is tightly fitted in the respective one of the pipette-tips B and abuts against an inner annular surface of a respective one of the pipette-tips B to connect the pipette-tips B to the tip connectors A 1  correctly and securely. 
     With reference to  FIG.  9    and  FIG.  10   , after connecting the pipette-tips B to the tip connectors A 1 , the second actuator  32  moves the pipette A upward, and then the pipette A is moved elsewhere to draw and dispense liquid. 
     To sum up, the tilt actuator  60  enables the tip connectors A 1  of the pipette A to be inserted into the mount openings of the pipette-tips B in an inclined manner. Therefore, the tip connectors A 1  can be inserted into the mount openings as long as the corners A 12  are above the mount openings. That is, when viewed laterally as shown in  FIGS.  5  to  7   , the tip connectors A 1  can be successfully inserted into the mount openings as long as each one of the corners A 12  is located between the widths of a respective one of the mount openings. There is no need to align the corners A 12  with the centers of the mount openings with precision, thereby greatly reducing need of positioning accuracy and making automation process of repeating the connection the pipette A with new pipet-tips B possible. Production speed and labor need are therefore reduced significantly. 
     Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and features of the invention, the disclosure is illustrative only. Changes may be made in the details, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.