Multichannel pipette

Abstract

Multichannel pipette, including: a pipette body in which a drive section for actuating a piston is housed; a lower part attached to a lower end of the pipette body; a unit housing that has a moving part provided in the lower part and attached to a lower end part of the drive section; and Several pipette tip holder units housed in the unit housing, each comprising a piston, a cylinder with which the piston slides, a pipette tip holder attached to a lower end part of the cylinder, and a connecting part that can be attached to and removed from any of several connecting parts provided in the moving part, wherein a convex switch, which is radially biased outwards by an elastic element of a pipette tip holder unit, is formed on an outer circumferential surface of the pipette tip holder unit, and several switch window parts are formed to allow the switches to be pressed in the lower part.

Description

Technical area

[0001] The present invention relates to a multi-channel pipette, and more particularly to a part including a cylinder, a piston and a pipette tip holder of the multi-channel pipette, and a peripheral part thereof. General state of the art

[0002] A pipette is a measuring instrument for dispensing a fixed volume of liquid. It treats a volume change caused by the movement of a movable piston in a cylinder as an air volume change, draws liquid with a volume corresponding to the air volume change into a pipette tip attached to a lower end of the cylinder, and dispenses the liquid. A type that attaches a single pipette tip is called a single-channel pipette, and a type that attaches multiple pipette tips simultaneously is called a multichannel pipette or multipipette.

[0003] Generally, the pipette tip attachments (pipette tip holders) in a multichannel pipette are designed as 8 or 12 channels. This is because a microplate, which is most commonly used as a container into which liquid is dispensed, contains 8 x 12 wells, and a microplate with 96 or more wells also contains wells that are an integer multiple of 96. A multichannel pipette includes a pipette main body housing a drive section that moves a piston, and a base attached to the lower end of the pipette main body.Inside the lower part, parts (pipette tip holder units) each including the cylinder, the piston, and the pipette tip holder are arranged side by side in a number corresponding to the number of pipette tips, and the plurality of pipette tip holder units are integrated (see Non-Patent Literatures 1 and 2).

[0004] The cited patent literature 1-4 shows further relevant prior art for the present invention. List of citationsNon-patent literature Non-patent literature 1: http: / / japan.mt.com / jp / ja / home / products / pipettes / electroni c-pipettes / multichannel-pipettes.html (accessed on November 6, 2015) Non-patent literature 2: http: / / www.gilson.com / Resources / Pipetman_Concept_Users_Gui de_English.pdf (accessed November 6, 2015) Patent literature Patent Literature 1: US 4,591,072 A Patent Literature 2: US 4,779,467 A Patent literature 3: EP 2 633 913 A1 Patent literature 4: DE 198 26 065 A1 Brief description of the inventionTechnical problem

[0005] In a facility using a pipette, the required number of wells into which a liquid is to be dispensed varies depending on the accuracy, production efficiency, and the volume of liquid to be dispensed for each purpose, so there is a desire to select the number of channels of the pipette. However, in a conventional multi-channel pipette, the number of channels specified by the manufacturer could not be changed.

[0006] In addition, a multi-channel pipette is used by simultaneously attaching and detaching pipette tips to and from it, so attaching / detaching pipette tips requires greater force than a single-channel pipette, and secure attachment is difficult. Therefore, during use, there were problems such as the pipette tip attachment part repeatedly slipping with the pipette tip, becoming worn and broken, leaking air from a small defect, and inability to dispense a scheduled volume. In the structure of the conventional multi-channel pipette, 8 or 12 pipette tip holder units are integrated into a base, so even if the above malfunction occurred, a malfunctioning unit or part could not be replaced or maintained independently.The pipette therefore had to be repaired by a manufacturer and there were problems because the repair took a lot of time and money.

[0007] The present invention was developed based on the problems of the conventional technology, and one of its objects is to provide a multi-channel pipette whose number of channels can be arbitrarily set and managed to improve the usability of the multi-channel pipette and to improve productivity, quality control, and maintainability in a research facility. The present invention is defined in claims 1, 3, and 4. Solution to the problem

[0008] To solve the problems described above, a multi-channel pipette according to one aspect of the present invention includes a pipette main body, a base attached to a lower end part of the pipette main body, and a plurality of pipette tip holder units housed in the base, each of the pipette tip holder units having a connecting part attachable to and detachable from any one of a plurality of connecting parts provided in a unit case in the base, and each of the pipette tip holder units being attachable to and detachable from the base.

[0009] A multi-channel pipette according to the present invention includes a pipette main body in which a drive section for actuating the piston is housed, a base attached to a lower end part of the pipette main body, a unit case having a movable part provided in the base and attached to a lower end part of the drive section, and a plurality of pipette tip holder units housed in the unit case and each having the piston, a cylinder in which the piston slides, a pipette tip holder attached to a lower end part of the cylinder, and a connecting part attachable to and detachable from any one of a plurality of connecting parts provided in the movable part.

[0010] In a first embodiment of the multi-channel pipette according to the invention, it is implemented that a convex switch, which is biased radially outward from the pipette tip holder unit by an elastic element, is formed on an outer peripheral surface of the pipette tip holder unit and a plurality of switch window parts for enabling pressing of the switch are formed in the lower part.

[0011] In the above-described aspect, it is also preferable that the switch is provided on a switch constituting member provided on the outer peripheral surface of the pipette tip holder unit, wherein a projecting engagement part extending radially outward from the pipette tip holder unit is formed on an outer peripheral surface of the switch constituting member, and a guide part guiding the projecting engagement part in the up-down direction is formed on the unit body.

[0012] In a second embodiment of the multi-channel pipette according to the invention, switch-forming elements are provided on a front side and / or a rear side of the unit housing, a convex switch, which is to be biased radially outward from the pipette tip holder unit by an elastic element, is formed on one end part of the switch-forming element and an engagement hole is formed on the other end part, a pipette tip holder-side claw part, which engages in the engagement hole when biased by the elastic element, is formed on the pipette tip holder unit, and switch window parts for enabling the switches to be pressed are formed in the lower part.

[0013] In a third embodiment of the multi-channel pipette according to the invention, it is implemented that openings for receiving slide switches are formed in the front and / or rear of the unit housing, a convex pressing part is formed convex radially inward of the pipette tip holder unit on a rear side of the switch, a housing-side claw part is formed convex radially inward of the pipette tip holder unit on a rear side of an opening end part of the opening in a sliding direction of the switch, a pipette tip holder-side claw part is formed convex radially inward of the pipette tip holder unit on the pipette tip holder unit, a pipette tip holder-side claw part which bends in a radial direction of the pipette tip holder unit is formed, and switch window parts for enabling the switches to be pressed are formed in the lower part.

[0014] In the above-described aspect, it is also preferable that a lip packing having a substantially U-shaped cut is provided at a lower end portion of the pipette tip holder.

[0015] In the aspect described above, it is also preferable that the connecting part and the connecting part are connected by magnetic force. Effect of the invention

[0016] According to the present invention, the usability and maintainability of the multi-channel pipette can be improved because the number of channels of a multi-channel pipette can be arbitrarily set by utilizing the function of the freely removable pipette tip holder. Short description of the drawings Fig. 1 is a front view of a multi-channel pipette according to one embodiment. Fig. 2 is a left-side view of Fig. 1. Fig. 3 is a perspective view showing the interior of a base according to a first embodiment. Fig. 4 is a perspective view showing a unit case and pipette tip holder units according to the first embodiment. Fig. 5 is an exploded perspective view of the pipette tip holder unit according to the first embodiment. Fig. 6 is a cross-sectional view of the lower part according to the first embodiment. Fig. 7 is a perspective view showing a unit case and a pipette tip holder unit according to a second embodiment. Fig. 8 are sectional views showing the locking engagement between the unit body and the pipette tip holder unit, in Fig. 7 shown, describe, and Fig. 8(a) is a view showing a state in which the pipette tip holder unit is removed from the unit body, Fig. 8(b) is a view showing a state in which the pipette tip holder unit is attached to the unit body, and Fig. 8(c) is a view showing a state in which the locking engagement between the pipette tip holder unit and the unit body is released. Fig. 9 is a perspective view showing a unit case and a pipette tip holder unit according to a third embodiment. Fig. 10 are sectional views showing the locking engagement between the unit body and the pipette tip holder unit, in Fig. 9 shown, describe, and Fig. 10(a) shows a state in which the pipette tip holder unit is removed from the unit body, Fig. 10(b) shows a state in which the pipette tip holder unit is attached to the unit body, and Fig. 10(c) shows a state in which the locking engagement between the pipette tip holder unit and the unit body is released. Description of the embodiments

[0017] Next, preferred embodiments of the present invention will be described with reference to the drawings. (First embodiment)(Whole pipette)

[0018] Fig. 1 is a front view of a multi-channel pipette according to an embodiment and Fig. 2 is a left-side view of Fig. 1. In this description, the front-to-back direction, the left-to-right direction and the up-down direction are shown in the drawings as the FB direction (front to back direction), the LR direction (left to right direction) and the UD direction (up-down direction), respectively.

[0019] A reference number 100 in Fig. 1 denotes a multi-channel pipette according to the present embodiment, and reference numeral 1 denotes a pipette main body. As shown in Fig. 2, the pipette main body 1 includes, inside a longitudinally long cylindrical casing, a feed screw (ball screw) 5, a stepping motor 6 (drive section) that rotates the feed screw 5 in both forward and reverse directions, an electric control board 10, and a battery 11.

[0020] On a front side of the pipette main body 1, a display section 18 and operation buttons 19 are provided ( Fig. 1). The control buttons 19 can be used to set the dispensing volume and dispensing mode, etc. Below the control buttons 19, there is an ejection button 12, which is used to remove pipette tips ( Fig. 2). The ejection button 12 is mechanically attached to an ejection device cover 73, which is described below ( Fig. 2). A spring is inserted between a shaft part 71, which will be described below, and the ejector cover 73, and when the ejection button 12 is pressed against a biasing force of this spring, the ejector cover 73 presses the pipette tips 8 ( Fig. 1) downwards and the pipette tips 8 are removed accordingly.

[0021] On a back side of the pipette main body 1, an operation button 14 for performing a dispensing operation is provided ( Fig. 2). A finger hook 16 is provided below the operating button 14, which contributes to support at the time of operation and serves as a stop when no operation is performed ( Fig. 2). On the left and right side surfaces of the pipette main body 1, a pair of charging station electrodes (+) 17a and (-) 17b are provided for electrical conduction to an external charger for charging the battery 11 ( Fig. 2). (lower part)

[0022] Reference numeral 7 denotes a lower part. The lower part 7 is a member to be attached to a lower end part of the pipette main body 1 and contains pipette tip holder units 20, each of which includes a pipette tip holder 23 ( Fig. 1). The pipette tip holder units 20 are described below. Fig. Fig. 3 is a perspective view showing the interior of the base 7 according to the first embodiment. As shown in Fig. 3, the lower part 7 includes the shaft part 71, the unit housing 72 and the ejector cover 73.

[0023] The shaft part 71 includes a feed shaft 711, which is to be attached to the feed spindle 5 ( Fig. 3). A lower end portion of the feed shaft 711 is integrated into the unit case 72, and an upper end portion of the feed shaft 711 is coupled to a lower end portion of the feed screw 5 by magnetic force or a removable engagement structure. An internal thread is formed on an inner periphery of an opening of the shaft portion 71, and an external thread is formed on an outer periphery of a lower end portion of the pipette main body 1, and the lower portion 7 can be screwed onto or detached from the pipette main body 1. (unit housing)

[0024] The unit housing 72 is provided inside the ejector cover 73 of the base 7 independently of the ejector cover 73 and is a housing in which a plurality of pipette tip holder units 20 are housed. The unit housing 72 has a double housing structure with a front housing 72F and a rear housing 72B and Fig. 3 shows a state in which the front housing 72F has been removed. The front housing 72F and the rear housing 72B are positioned and engaged with each other by concave and convex shapes provided at four positions in the housings.

[0025] Fig. 4 is a perspective view showing a unit case 72 according to the first embodiment. Fig. 4 also shows a state in which the front housing 72F has been removed. As in Fig. 4, the unit case 72 of the present embodiment holds pipette tip holder units 20 in parallel in a direction (left-right direction) orthogonal to an axial direction (up-down direction) of the feed shaft 711. Slide rails 75 are formed on a left side surface 72L and a right side surface 72R of the unit case 72 at upper portions. A movable part 721 is provided between the slide rails 75 and 75. The movable part 721 has guide parts at both ends and moves in the up-down direction on the slide rails 75. The guide parts of the movable part 721 may have a shape known to those skilled in the art, such as a rail shape or a bearing shape.

[0026] In the movable part 721, a plurality of connecting parts 74 for connecting the pipette tip holder units 20 are formed in the left-to-right direction. Each connecting part 74 is a circular groove formed on a lower surface of the movable part 721, and its inner surface has a magnet 741 ( Fig. 4). In the present embodiment, connecting parts 74 are formed at equal intervals at 12 positions in the unit body 72, so that the pipette tip attachment part has 8 to 12 channels.

[0027] In the lower portions of the inner surfaces of the front housing 72F and the rear housing 72B of the unit case 72, a plurality of positioning frames 722 are formed in the left-to-right direction. The positioning frame 722 is a frame with a substantially U-shaped section that covers the left and right sides of each cylinder 22 (described below) of the pipette tip holder unit 20, is formed for each width of the cylinder 22, and holds a peripheral surface of the cylinder 22 in a cylindrical shape. The positioning frame 722 functions as a positioner and rotation stopper of the pipette tip holder unit 20.

[0028] Fig. 6 is a cross-sectional view of the lower part 7 according to the first embodiment. As in Fig. As shown in Figure 6, front end portions of the positioning frame 722 of the front housing 72F extend forward in plate shapes and become guide portions 79 extending in the up-down direction. A plurality of guide portions 79 are formed at intervals substantially equal to the widths of the protruding engagement portions 27 described below on the side of the pipette tip holder unit 20 in the left-right direction.

[0029] The ejector cover 73 is a removal mechanism for the pipette tips 8 described above. The ejector cover 73 is formed by a double housing construction including the front cover 73F and the rear cover 73B ( Fig. 2). The front panel 73F and the rear panel 73B are engaged with each other by matching concave and convex shapes provided at four corners and accordingly take up the Fig. 1. In the front cover 73F, switch window parts 78 for exposing switches 29 of the pipette tip holder units 20, described later, from the front cover 73F are formed at 12 positions corresponding to the positions of the pipette tip holder units 20 ( Fig. 1). The switch window parts 78 do not need to be through-holes, as long as they have shapes that allow pressing on the switches 29. As in Fig. As shown in Fig. 6, on inner surfaces (the front cover 73F and the rear cover 73B) of the ejector cover 73, a plurality of reinforced walls 76 are formed in the left-to-right direction, projecting toward the side of the unit case 72 and extending in the up-down direction. By forming the reinforced walls 76, a bending stress to be applied to the ejector cover 73 when attaching or removing the pipette tips 8 can be dispersed in the up-down direction, and breakage of the ejector cover 73 can be reduced. (pipette tip holder unit)

[0030] Fig. 5 is an exploded perspective view of a pipette tip holder unit 20 according to the first embodiment. As shown in Fig. 5, the pipette tip holder unit 20 includes a piston 21, a cylinder 22, a pipette tip holder 23, a connecting part 24, and a switch-forming element 25.

[0031] The cylinder 22 contains a metal sleeve in a long, thin, and round cylindrical housing. The pipette tip holder 23 is attached to a lower end portion of the cylinder 22. The pipette tip holder 23 has a columnar shape, and a concave groove 235 ( Fig. 5). A lip packing 26 with a U-shaped longitudinal section is installed in the concave groove 235. The pipette tip 8 is attached to the lower end part of the pipette tip holder 23, and a portion between the pipette tip holder 23 and the pipette tip 8 is sealed liquid-tight by the lip packing 26. The packing used in this case may be an O-ring. By providing an O-ring or a lip packing 26 at the lower end part of the pipette tip holder 23, the sliding resistance between the pipette tip holder 23 and the pipette tip 8 is reduced and durability is improved. The use of the lip packing 26 is preferable because a clamping tolerance range is expanded and, accordingly, the sealing performance is improved and torsion is less likely to be caused by inserting the pipette tip 8.At an upper end portion of the pipette tip holder 23, a concave / convex groove is formed on the outer peripheral surface, and this concave / convex groove enables the pipette tip holder 23 to be pressed onto and pulled off from a lower end portion of the cylinder 22.

[0032] A switch-forming member 25 is attached to an upper end portion of the cylinder 22. The switch-forming member 25 has a cylindrical shape overall, within which a piston shaft 211 described below is movable. At a lower end portion of the switch-forming member 25, a concave / convex groove is formed on an outer peripheral surface, and this concave / convex groove enables the lower end portion of the switch-forming member 25 to be pressed onto and withdrawn from the upper end portion of the cylinder 22. At an upper end side of the switch-forming member 25, in a region of an outer peripheral surface, that is, in the present embodiment, in a region corresponding to an arc of substantially 1 / 6 of the outer circumference, a protruding engagement portion 27 is formed, which projects radially outward from the pipette tip holder unit 20 in a rectangular shape ( Fig. 5). The protruding engagement part 27 may be formed in a smaller area or a larger area, as long as the area is a portion of the cylinder 22. The interior of the protruding engagement part 27 is hollow, and this hollow part is provided with a spring (elastic member) 28 and a convex switch 29 that is biased radially outward from the pipette tip holder unit 20 by the spring 28. It is also possible for the switch 29 itself to be made of an elastic member such as silicone rubber or to be biased by a structure provided with another elastic function. The switch 29 is biased by the spring 28 so that its head portion protrudes outward from the protruding engagement part 27 ( Fig. 4).

[0033] As described above, in the front housing 72F of the unit case 72, the guide parts 79 extending in the up-down direction are formed at intervals substantially equal to the widths of the projecting engagement parts 27 ( Fig. 6). Accordingly, even after the pipette tip holder unit 20 is removed from the unit case 72, the pipette tip holder unit 20 can return to its original position because the protruding engagement part 27 is guided by the guide parts 79 in the up-down direction and positioned in the left-right direction by the positioning frame 722 of the unit case 72. The protruding engagement part 27 and the guide parts 79 also function as rotation stops of the cylindrical cylinder 22 when the pipette is operated.

[0034] The piston 21 is provided at a lower end portion of the piston shaft 211 and is inserted into the interior of the cylinder 22 via a piston lip packing 212 ( Fig. 5). A sealing material is provided on an outer peripheral surface of the piston shaft 211, and the piston shaft 211 can move up and down inside the cylinder 22. A connecting part 24 is attached to an upper end portion of the piston shaft 211. The connecting part 24 is an iron screw and is press-fitted onto the upper end portion of the piston shaft 211 and fixed against separation. As described above, since the connecting part 74 of the unit case 72 has a magnet, the connecting part 24, which is an iron screw, is connected to the connecting part 74 by magnetic force.

[0035] In each pipette tip holder unit 20, since the piston shaft 211 is connected to the movable part 721 of the unit body 72 by magnetic force, when the feed screw 5 is moved upward, the movable part 721 of the unit body 72 is moved upward via the feed shaft 711, and the pistons 21 of the pipette tip holder units 20 simultaneously move upward inside the cylinders 22, and accordingly, a liquid is sucked into the pipette tips 8. When the feed screw 5 is moved downward, the pistons 21 of the respective pipette tip holder units 20 simultaneously move downward inside the cylinders 22, and accordingly, a liquid is dispensed from the pipette tips 8. (Use)

[0036] A use of the multi-channel pipette 100 constructed as described above will be described. When a user wishes to use the multi-channel pipette 100, they attach the number of pipette tip holder units 20 corresponding to the desired number of channels to be used to the base 7 according to a requirement for the number of wells, etc. As the number of pipette tip holder units 20 to be attached to the base 7 (the number of channels), 12 channels, which is the maximum number in the present embodiment, or 8 channels, 4 channels, 2 channels, or any number may be used. Channels do not necessarily have to be formed adjacent to each other and may be formed to be spaced apart from each other.At this time, the pipette tip holder unit 20 can be easily attached to the base 7 (unit body 72) by magnetic connection between the connecting part 24 and the connecting part 74 of the unit body 72.

[0037] When the pipette tip holder unit 20 is to be removed from the base 7, the switch 29 exposed from the window part 78 of the base 7 (ejector cover 73) is pressed to release the locking engagement between the window part 78 and the unit case 72F, and the pipette tip holder unit 20 is pulled out, and accordingly, the pipette tip holder unit 20 can be detached from the base 7 (unit case 72) by a single touch. (Second embodiment)

[0038] In a second embodiment, the switch shape between the pipette tip holder unit 20 and the unit case 72 is changed from that in the first embodiment. Components that are the same as in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted.

[0039] Fig. Fig. 7 is a perspective view showing a unit case 72 and a pipette tip holder unit 20 according to the second embodiment, Fig. Fig. 8(a) is a view showing a state in which the pipette tip holder unit 20 is removed from the unit case 72, Fig. Fig. 8(b) is a view showing a state in which the pipette tip holder unit 20 is attached to the unit case 72, and Fig. Fig. 8(c) is a view showing a state in which the locking engagement between the pipette tip holder unit 20 and the unit case 72 is released. The unit case 72 of the present embodiment also has a double case structure consisting of a front case 72F and a rear case 72B, and a positioning frame 722 having a substantially U-shaped section holds a peripheral surface of a cylinder 22 having a cylindrical shape ( Fig. 7). The positioning frame 722 functions as a positioner and a rotation stopper of the pipette tip holder unit 20. In the unit case 72 of the second embodiment, slide rails 75 are also formed on the left side surface 72L and the right side surface 72R thereof in upper portions, and a movable part 721 is provided between the slide rails 75 and 75. In the movable part 721, connecting parts 74 for connecting the pipette tip holder units 20 are formed at 12 positions in the left-to-right direction.

[0040] In the second embodiment, switch-forming elements 25 are formed on an outer surface of the front housing 72F of the unit case 72 (see Fig. 8. Fig. 7 shows a state in which the rightmost row includes the switch forming member 25 and the pipette tip holder unit 20 is attached thereto, and in other rows, descriptions of the switch forming members 25 and the pipette tip holder units 20 are omitted.

[0041] The switch-forming member 25 is in the shape of a plate and is rotatable in the front-to-back direction about a fulcrum portion 292 formed on an outer surface of the front-side housing 72F. A convex switch 29 is provided at an upper end portion thereof, and an engaging hole 293 is formed at a lower end portion thereof, which engages a pipette tip holder-side claw portion 251 described below. On a rear surface side of the switch 29, a spring (elastic member) 28 is provided between a rear surface of the switch-forming member 25 and the unit housing 72, which biases the switch 29 radially outward from the pipette tip holder unit (in front of the pipette).

[0042] The pipette tip holder unit 20 of the second embodiment also includes the piston 21, the cylinder 22, the pipette tip holder 23, the connecting part 24 and the lip packing 26 ( Fig. 7). The pipette tip holder 23 of the second embodiment has, on an outer peripheral surface of the pipette tip holder 23, a locking engagement portion 232 integrally formed with the pipette tip holder 23. The locking engagement portion 232 extends from a position higher than the concave groove 235 of the pipette tip holder 23 in a plate shape parallel to and at a predetermined distance from the outer surface of the pipette tip holder 23 toward an upper end portion of the pipette tip holder 23, and has a convex pipette tip holder-side claw portion 231 on a front surface of a free end portion of the locking engagement portion 232. The locking engagement portion 232 may be formed as a separate body that may be attached to the outer peripheral surface of the pipette tip holder 23.

[0043] In the present embodiment, in a similar manner to the first embodiment, switch window parts 78 for exposing switches 29 from the front panel 73F are provided at 12 positions on the front panel 73F of the base 7, although they are not shown in the drawings. (Use)

[0044] A use of the multi-channel pipette 100 according to the second embodiment will be described. The pipette tip holder units 20 are attached to the base 7 in a similar manner as in the first embodiment. In the present embodiment, when the pipette tip holder unit 20 is attached to the base 7 as shown in Fig. 8(b), the pipette tip holder side claw part 231 and the engagement hole 293 of the unit case 72 are engaged with each other, and the pipette tip holder unit 20 is accordingly prevented from being separated from the unit case 72, so that the pipette tip holder unit 20 cannot be removed from the unit case 72 simply by pulling the pipette tip holder unit 20.

[0045] To remove the pipette tip holder unit 20, as shown in Fig. 8(c), the switch 29 is pressed with a finger to release the locking engagement between the pipette tip holder-side claw part 231 and the engagement hole 293. In this state, the pipette tip holder unit 20 can be released by pulling the pipette tip holder unit 20 out of the base 7 (unit case 72) by a single touch. (Third embodiment)

[0046] In a third embodiment, the switch shape between the pipette tip holder unit 20 and the unit case 72 is changed from that in the first embodiment. Components that are the same as in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted.

[0047] Fig. Fig. 9 is a perspective view showing a unit case 72 and a pipette tip holder unit 20 according to the third embodiment, Fig. 10(a) is a view showing a state in which the pipette tip holder unit 20 is removed from the unit case 72, Fig. 10(b) is a view showing a state in which the pipette tip holder unit 20 is attached to the unit case 72 and Fig. 10(c) is a view showing a state in which the locking engagement between the pipette tip holder unit 20 and the unit case 72 is released. The unit case 72 of the present embodiment also has a double case structure consisting of a front case 72F and a rear case 72B, and a positioning frame 722 having a substantially U-shaped section holds a peripheral surface of a cylinder 22 having a cylindrical shape ( Fig. 9). The positioning frame 722 functions as a positioner and a rotation stopper of the pipette tip holder unit 20. In the unit case 72 of the third embodiment, slide rails 75 are formed on a left side surface 72L and a right side surface 72R thereof at upper portions, and a movable part 721 is provided between the slide rails 75 and 75. In the movable part 721, connecting parts 74 to which the pipette tip holder units 20 are connected are formed at 12 positions in the left-to-right direction.

[0048] In the third embodiment, slide switches 29 are formed on an outer surface of the front housing 72F of the unit case 72 (see Fig. 9. Fig. 9 shows a state in which the rightmost row includes the switch 29 and a pipette tip holder unit 20 is attached thereto, and in other rows, descriptions of the switches 29 and the pipette tip holder units 20 are omitted.

[0049] In the left-to-right direction of the unit case 72, 12 switches 29 are provided. Openings 296 are provided in a side surface of the front case 72F, and the switches 29 are slidably held in the openings 296 downward. Each switch 29 is in the shape of a plate, and at a substantially central position of a rear side thereof, a convex pressing part 294 is convexly formed radially inward of the pipette tip holder unit 20 (rear of the pipette). At a lower opening end part of the opening 296, at a rear side thereof, a case-side claw part 295 is convexly formed radially inward of the pipette tip holder unit 20 (rear of the pipette).

[0050] The pipette tip holder unit 20 of the third embodiment also includes the piston 21, the cylinder 22, the pipette tip holder 23, the connecting part 24, and the lip packing 26. In the third embodiment, a switch receiving member 271 is formed at an upper end portion of the cylinder 22. The switch receiving member 271 has a cylindrical shape overall, within which a piston shaft 21 is movable. A concave / convex groove is formed on the outer peripheral surface of a lower end portion of the switch receiving member 271. This concave / convex groove enables a lower end portion of the switch receiving member 271 to be pressed onto and removed from the upper end portion of the cylinder 22.In a region of an outer peripheral surface of the switch receiving member 271, that is, in the present embodiment, in a region corresponding to an arc of substantially 1 / 6 of the outer circumference, a projecting engagement part 27 projecting in a rectangular shape radially outward from the pipette tip holder unit 20 (in front of the pipette in the present embodiment) is formed (. Fig. 9). The interior of the protruding engagement part 27 of the present invention is also hollow, and a front side of the protruding engagement part 27 has a plate spring part 272 formed by a cut in the axial direction of a pipette tip holder unit. At a free end portion of the plate spring part 272, a pipette tip holder-side claw part 251 is formed convexly radially outward from the pipette tip holder unit (in front of the pipette).

[0051] The positioning frame 722 of the third embodiment generally assumes a U-shape. In detail, the positioning frame is formed such that a free end portion has a substantially V-shape and a base end portion has a right angle. The free end portion firmly holds the peripheral surface of the cylinder 22 and functions as a positioner of the pipette tip holder unit 20, and the base end portion functions as a guide portion that guides the protruding engagement portion 27 in the up-down direction and as a rotation stopper.

[0052] In the present embodiment, in a similar manner to the first embodiment, switch window parts 78 for exposing switches 29 from the front panel 73F are provided at 12 positions on the front panel 73F of the base 7, although they are not shown in the drawings. (Use)

[0053] A use of the multi-channel pipette 100 according to the third embodiment will be described. The pipette tip holder unit 20 is attached to the base 7 in a similar manner as in the first embodiment. In the present embodiment, when the pipette tip holder unit 20 is attached to the base 7 as shown in Fig. 10(b), the pipette tip holder side claw part 251 and the case side claw part 295 of the unit case 72 engage with each other and the pipette tip holder unit 20 is prevented from being detached from the unit case 72, so that the pipette tip holder unit 20 cannot be removed from the unit case 72 simply by pulling the pipette tip holder unit 20.

[0054] To remove the pipette tip holder unit 20, as shown in Fig.As shown in Figure 10(c), the switch 29 is pushed downward. With this sliding, the convex pressing portion 294 of the switch 29 presses the plate spring portion 272 of the pipette tip holder unit 20, causing the plate spring 272 to bend. Accordingly, the engagement between the pipette tip holder-side claw portion 251 and the housing-side claw portion 295 is released. In this state, the pipette tip holder unit 20 can be released by pulling the pipette tip holder unit 20 out of the base 7 (unit housing 72) by a single touch.

[0055] According to the first to third embodiments described above, by the structure that each pipette tip holder 20 is removable from the base body 7 alone by providing the connecting part 74 on the base body 7 (unit case 72) and by providing a connecting part 24 removably connectable to the connecting part 74 on each pipette tip holder unit 20, the number of channels of the multi-channel pipette 100 can be arbitrarily set.

[0056] Accordingly, depending on the accuracy and efficiency required for dispensing, the cost of a liquid to be dispensed or an available amount of a sample to be dispensed, or the skill of a user and liquid properties, etc., pipette tip holder units 20 corresponding to the number of channels required are attached to the base 7, and a user can therefore select the number of channels himself.

[0057] Furthermore, each pipette tip holder unit 20 can be removable from the base 7 alone, so that even if a pipette tip holder 23 of one of the pipette tip holder units 20 is worn and broken, a user can remove the affected pipette tip holder unit 20 himself and replace only the pipette tip holder 23. Therefore, the time and cost for repairing the pipette can be significantly reduced.

[0058] Next, preferred modifications of the above-described embodiment will be described. All of the above-described embodiments have a form in which the multi-channel pipette 100 accommodates up to 12 pipette tip holder units 20 (up to 12 channels) in the unit case 72, but, for example, a modified form in which up to 8 pipette tip holder units 20 (up to 8 channels) are accommodated is also desirable. In addition, the multi-channel pipette 100 may have a form in which up to 16 pipette tip holder units 20 (up to 16 channels), up to 4 pipette tip holder units 20 (up to 4 channels), or up to 2 pipette tip holder units 20 (up to 2 channels) are accommodated. That is, the maximum number of channels of the multi-channel pipette 100 can be arbitrary, and even if the number of channels is changed, the modified form is also included in the present invention.

[0059] In all the above-described embodiments, the terminal part 74 and the connecting part 24 can be attachable to and detachable from each other by magnetic connection, but they can also be attachable to and detachable from each other even if the connection method is changed to a combination of screws or claws. In all the above-described embodiments, the switches 29 are provided on the front side (front panel 73F), but they can also be provided on the rear side (rear panel 73B), or they can be provided on both the front and rear sides, so that the pipette tip holder units 20 on both sides are prevented from being detached and the fastening strength is improved.

[0060] In all of the above-described embodiments, an electric type in which the piston 21 is driven by an electric motor 6 is described by way of example, but the invention also applies to a manual type in which the piston is driven manually. All of the above-described embodiments can be applied to a single pipette.

[0061] Preferred embodiments and modifications of the present invention are described above, and each embodiment and each modification can be combined based on the knowledge of a person skilled in the art, and such a combined embodiment also falls within the scope of the present invention. List of reference symbols 100 multi-channel pipettes 1 pipette main body 6 Motor (drive section) 7 Lower part 20 Pipette tip holder unit 21 pistons 22 cylinders 23 pipette tip holders 24 connecting part 25 Switch-forming element 26 lip packs 27 Protruding engagement part 28 Spring (elastic element) 29 switches 72 unit housings 74 connecting part 78 Switch window part 79 Guide part 231 Pipette tip holder side claw part 293 intervention hole 294 Convex pressure part 295 Housing-side claw part 296 Opening 711 Feed shaft (lower end of the drive section)

Claims

[1] Multi-channel pipette, comprising: a pipette main body in which a drive section for actuating a piston is housed; a lower part attached to a lower end part of the pipette main body; a unit housing having a movable part provided in the base and attached to a lower end part of the drive section; and a plurality of pipette tip holder units housed in the unit body and each including the piston, a cylinder with which the piston slides, a pipette tip holder attached to a lower end portion of the cylinder, and a connecting portion attachable to and detachable from any one of a plurality of connecting portions provided in the movable portion; wherein a convex switch biased radially outward from a pipette tip holder unit by an elastic member is formed on an outer peripheral surface of the pipette tip holder unit, and a plurality of switch window portions for enabling the switches to be pressed are formed in the lower portion. [2] The multi-channel pipette according to claim 1, wherein the switch is provided on a switch forming member provided on an outer peripheral surface of the pipette tip holder unit, a projecting engagement part extending radially outward from the pipette tip holder unit is formed on an outer peripheral surface of the switch forming member, and a guide part guiding the projecting engagement part in the up-down direction is formed on the unit body. [3] Multi-channel pipette, comprising: a pipette main body in which a drive section for actuating a piston is housed; a lower part attached to a lower end part of the pipette main body; a unit housing having a movable part provided in the base and attached to a lower end part of the drive section; and a plurality of pipette tip holder units housed in the unit housing and each comprising the piston, a cylinder with which the piston slides, a pipette tip holder attached to a lower end portion of the cylinder, and a connecting portion attachable to and detachable from any of a plurality of connecting portions provided in the movable portion, wherein switch-forming elements are provided on a front and / or a rear side of the unit housing; on the switch-forming element, a convex switch which is to be biased radially outwardly from the pipette tip holder unit by an elastic element is formed at one end part and an engagement hole is formed at the other end part, a claw part on the pipette tip holder side, which engages in the engagement hole when pretensioned by the elastic element, is formed on the pipette tip holder unit, and switch window parts are designed in the lower part to enable the switches to be pressed. [4] Multi-channel pipette, comprising: a pipette main body in which a drive section for actuating a piston is housed; a lower part attached to a lower end part of the pipette main body; a unit housing having a movable part provided in the base and attached to a lower end part of the drive section; and a plurality of pipette tip holder units housed in the unit housing and each comprising the piston, a cylinder with which the piston slides, a pipette tip holder attached to a lower end portion of the cylinder, and a connecting portion attachable to and detachable from any of a plurality of connecting portions provided in the movable portion, wherein openings for slide switches are provided in the front and / or rear of the unit housing, on a back side of the switch, a convex pressure part is formed convex radially inward of the pipette tip holder unit, and on a back side of an opening end part of the opening in a sliding direction of the switch, a housing-side claw part is formed convex radially inward of a pipette tip holder unit, a pipette tip holder-side claw part which bends in a radial direction of the pipette tip holder unit is formed on the pipette tip holder unit, and switch window parts are designed in the lower part to enable the switches to be pressed. [5] A multi-channel pipette according to any one of claims 1 to 4, wherein a lip packing having a substantially U-shaped cut is provided at a lower end portion of the pipette tip holder. [6] Multi-channel pipette according to claims 1 to 5, wherein the connecting part and the connecting part are connected by magnetic force.

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