PIPETTE FOR USE WITH A PIPETTE TIP

Abstract

A pipette for use with a pipette tip includes a chassis. An apparatus is coupled to the chassis and is configured to detachably hold at least one pipette tip. A drive apparatus is coupled to the chassis and is configured to displace a displacement element to suck liquid specimens into the pipette tip and eject the specimens from the pipette tip. A tubular pipette housing is configured to surround and connect to the chassis. The longitudinal direction of the chassis is aligned in the longitudinal direction of the pipette housing. The chassis includes multiple chassis elements which are arranged behind one another and are connected to one another. The apparatus for detachably holding at least one pipette tip and the drive apparatus are connected to one or more of the multiple chassis elements.

Claims

1. A pipette for use with a pipette tip, comprising: an chassis extending along a chassis axis; an apparatus connected to the chassis and configured to detachably hold at least one pipette tip; a drive apparatus coupled to the chassis and configured to displace a displacement element to suck liquid specimens into the pipette tip and eject the specimens from the pipette tip; a tubular pipette housing extending along a housing axis and configured to surround and connect to the chassis, wherein the chassis axis extends in a same direction as the housing axis; wherein the chassis comprises a plurality of chassis elements behind one another and connected to one another, and wherein the apparatus configured to detachably hold at least one pipette tip and the drive apparatus are configured to connect to at least one of the plurality of chassis elements.

2. The pipette according to claim 1, wherein each of the plurality of chassis elements are tubular.

3. The pipette according to claim 1, wherein at least one of: one or more components of the drive apparatus for displacing a displacement element are connected to at least one chassis element; at least one component of a display apparatus configured for displaying an adjusted pipetting volume is connected to at least one of the plurality of chassis elements; at least one component of an ejection apparatus configured for ejecting at least one pipette tip is connected to at least one of the plurality of chassis elements; the components of an apparatus configured to detachably hold at least one pipette tip are connected to at least one of the plurality of chassis elements; and at least one component of an apparatus configured to detachably hold the plurality of chassis elements in the pipette housing is connected to at least one of the plurality of chassis elements.

4. The pipette according to claim 3, further comprising at least one of: a first assembly comprising a chassis element and at least one component of the drive apparatus; a second assembly comprising a chassis element and at least one component of the display apparatus; a third assembly comprising a chassis element and at least one component of the ejection apparatus; a fourth assembly comprising a chassis element and at least one component of the apparatus for detachably holding at least one pipette tip; and a fifth assembly comprising a chassis element and at least one component of the apparatus for detachably holding the plurality of chassis elements in the pipette housing.

5. The pipette according to claim 1, further including at least one of: the drive apparatus comprises a first subassembly which is connected to at least one of the plurality of chassis elements; a display apparatus comprises a second subassembly which is connected to at least one of the plurality of chassis elements; an ejection apparatus comprises a third subassembly connected to at least one of the plurality of chassis elements; the apparatus configured to detachably hold at least one pipette tip comprises a fourth subassembly connected to at least one of the plurality of chassis elements; and an apparatus configured to detachably hold the plurality of chassis elements in the pipette housing and further comprising at least one fifth subassembly connected to at least one of the plurality of chassis elements.

6. The pipette according to claim 1, further comprising at least one of: the drive apparatus is configured to connect to a first chassis element; a display apparatus is configured to connect to a second chassis element; the drive apparatus is configured to connect to a third chassis element; the apparatus configured to detachably hold at least one pipette tip is configured to connect to a fourth chassis element; and an apparatus configured to detachably hold the plurality of chassis elements in the pipette housing is configured to connect to the fourth chassis element.

7. The pipette according to claim 1, wherein at least one of: (i) components of the drive apparatus are connected to a first chassis element; and (ii) components of a display apparatus are connected to the first chassis element.

8. The pipette according to claim 7, wherein at least one of: (i) components of the drive apparatus are configured to couple to a second chassis element; and (ii) components of an ejection apparatus are configured to connect to a second chassis element.

9. The pipette according to claim 8, wherein at least one of: (i) components of the drive apparatus are configured to connect to a third chassis element; and (ii) components of the ejection device are configured to connect to a fourth chassis element.

10. The pipette according to claim 9, wherein the first chassis element is positioned above the second chassis element, wherein the second chassis element is positioned above the third chassis element, and wherein the third chassis element is positioned above the fourth chassis element.

11. The pipette according to claim 1, wherein the drive apparatus comprises: a threaded spindle configured to engage in an internal thread of a first chassis element, wherein the threaded spindle is configured to be adjusted in a longitudinal direction of the first chassis element; an adjusting sleeve rotatably mounted in the first chassis element and configured to connect to the threaded spindle, wherein the adjusting sleeve is configured to rotate conjointly with the threaded spindle, and wherein the adjusting sleeve and the threaded spindle are configured to be displaced in the longitudinal direction relative to one another; an adjusting knob configured to protrude upward from the first chassis element; and a lifting rod configured to traverse the threaded spindle and extend in the longitudinal direction, wherein the lifting rod and the at least one projection are configured to be displaced to contact a first stop on an underside of the threaded spindle and forming a drive element below a projection and protruding from the first chassis element with an operating knob on an upper end.

12. The pipette according to claim 11, further comprising a second chassis element coupled to a lower end of the first chassis element and a counter coupled to a holding apparatus on a casing of the second chassis element and of the first chassis element.

13. The pipette according to claim 12, further comprising: a third chassis element connected to the lower end of at least one of the first chassis element and the second chassis element; an overstroke system defining a passage arranged inside the third chassis element, wherein a lifting rod extends downward through the passage, wherein during a downward displacement, the lifting rod, after the projection hits a second stop on a top of the overstroke system, is configured to be displaced downward against a force of an overstroke spring.

14. The pipette according to claim 13, further comprising a fourth chassis element configured as a tubular coupling element and comprising a lower part comprising a connecting spigot inserted into the tubular coupling element, wherein the lower part comprises at least one displacement element positioned in a displacement chamber and a hollow spigot connected to the displacement chamber and configured to detachably hold a pipette tip.

15. The pipette according to claim 14, wherein the lower part comprises a drive rod coupled to the lower end of the lifting rod in the connecting spigot and further configured to couple to the tubular coupling element, wherein the drive rod is configured to connect to at least one piston which is displaceably arranged in a cylinder, and wherein the cylinder is arranged in the lower part and is configured to connect to a spigot configured to detachably hold the pipette tip protruding from the lower part.

16. The pipette according to claim 15, further comprising multiple cylinders held parallel to one another in a box-like lower part chassis, wherein the box-like lower part chassis is configured to connect at a top to the spigot to form a lower part housing.

17. The pipette according to claim 7, wherein the first chassis element comprises: an adjusting apparatus with an adjusting knob configured to adjust a dosing volume, wherein the adjusting knob is configured to protrude upward from the first chassis element and is rotatably mounted on the first chassis element; and a counter coupled to the adjusting apparatus and configured for adjusting the adjusted dosing volume.

18. The pipette according to claim 17, further comprising a second chassis element configured to rotatably support a rotating sleeve on a casing and an actuating element arranged on the second chassis element that is configured to execute a dosing stroke and eject a pipette tip from a spigot.

19. The pipette according to claim 18, further comprising a switching apparatus connected to the second chassis element, wherein the switching apparatus is coupled to the actuating element and configured to displace a lifting rod to displace a tip piston in different directions during successive displacements of the actuating element by a downward stroke.

20. The pipette according to claim 19, further comprising: a third chassis element configured to connect to a toothed rod; a lifting rod and a gear mechanism configured to couple the toothed rod and the piston lifting rod; guides for a piston ejector; and an apparatus for adjusting a display sleeve.

21. The pipette according to claim 20, further comprising an ejection apparatus configured to eject pipette tips from the spigot and be guided on one of: (i) the first chassis element; and (ii) a fourth chassis element.

22. The pipette according to claim 1, wherein adjacent chassis elements of the plurality of chassis elements are connected to one another.

23. The pipette according to claim 22, wherein adjacent chassis elements comprise positioning elements configured to hold the adjacent chassis elements in position relative to one another, wherein the positioning elements comprise at least one pair of magnetic components.

24. The pipette according to claim 1, wherein at least one of the plurality of chassis elements comprises a position surface configured to engage a test gage.

25. The pipette according to claim 1, wherein the pipette housing is connected to a lower end of the chassis.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The invention is described in greater detail below with reference to the accompanying drawings of exemplary embodiments, wherein:

[0063] FIG. 1 shows an upper part of an air cushion pipette in a longitudinal section;

[0064] FIG. 2 shows chassis elements with components connected thereto of the same pipette in an exploded view;

[0065] FIG. 3 shows the same chassis elements in an exploded view;

[0066] FIG. 4 shows chassis elements from FIG. 3, joined together, in a side view;

[0067] FIG. 5 shows chassis elements connected to components from FIG. 2 partially joined together in a perspective view, obliquely from the side;

[0068] FIG. 6 shows chassis elements connected to components from FIG. 2, joined together, in a side view;

[0069] FIG. 7 shows chassis elements connected to components, joined together with a first exemplary embodiment of an ejection apparatus in a perspective view, obliquely from the side;

[0070] FIG. 8 shows chassis elements connected to components, joined together with a second exemplary embodiment of an ejection apparatus in a perspective view, obliquely from the side;

[0071] FIG. 9 shows a chassis element with an overstroke system of the same pipette in an exploded view, obliquely from below and from the side;

[0072] FIG. 10 shows a chassis element with a counter of the same pipette in a perspective view from the left side;

[0073] FIG. 11 shows a chassis element with a counter of the same pipette in a perspective view from the right side;

[0074] FIG. 12 shows a lower part of the same pipette without a lower part housing in a partially broken front view;

[0075] FIG. 13 shows a positive displacement pipette in a front view;

[0076] FIG. 14 shows the same positive displacement pipette in a side view along the longitudinal axis in a plane rotated by 90° with respect to FIG. 13;

[0077] FIG. 15 shows chassis elements of the same pipette equipped and preassembled with components in a perspective view, obliquely from below and from the side;

[0078] FIG. 16 shows the first chassis element of the same positive displacement pipette in a perspective view, obliquely from below and from the side;

[0079] FIG. 17 shows the same chassis element equipped with components in a perspective view, obliquely from below and from the side;

[0080] FIG. 18 shows a second chassis element from above of the same pipette in a perspective view from below and from the side;

[0081] FIG. 19 shows the same chassis element equipped with components in a perspective view from below and from the side;

[0082] FIG. 20 shows a third chassis element from above of the same pipette in a perspective view from below and from the side;

[0083] FIG. 21 shows the same chassis element equipped with components in a perspective view from below and from the side;

[0084] FIG. 22 shows the fourth chassis element from above of the same pipette in a perspective view from below and from the side;

[0085] FIG. 23 shows the same chassis element equipped with components in a perspective view from below and from the side;

[0086] FIG. 24 shows the coupling of the assembly from FIG. 22 to the counter from FIG. 16 in a perspective view, obliquely from below and from the side.

DETAILED DESCRIPTION OF THE INVENTION

[0087] According to FIGS. 1 to 11, the air cushion pipette 1.1 has an upper part 2 which comprises a chassis 3, components 4 (e.g., a display ring) and assemblies 5 (e.g., a counter, cf. FIG. 2) as well as a tubular pipette housing 6.

[0088] The chassis 3 comprises four tubular chassis elements 7.1, 7.2, 7.3, 7.4 which are detachably connected to one another. The chassis 3 has a first chassis element 7.1 at the top, which has an upper portion 9.1 delimited by upper hollow cylindrical segments 8.1, 8.2 of larger diameter and, at the bottom, a lower portion 9.2 delimited by lower hollow cylindrical segments 8.3, 8.4 of smaller diameter (see FIG. 3). Therebetween, an upwardly protruding dome 12 is arranged on a plate 10 having a central through-hole 11. At the top, the upper hollow cylindrical segments 8.1, 8.2 are connected to one another on one side by a circular arc-shaped crosspiece 13 which has a pocket opened downward 14.

[0089] A substantially annular second chassis element 7.2 is arranged therebelow, which can be pushed from below onto the lower portion 9.2 of the first chassis element 7.1. Grooves 15.1, 15.2 directed in the axial and in the circumferential direction of a bayonet connection 16 are configured on the inner sides of the lower portion 9.2 of the first chassis element 7.1. The second chassis element 7.2 has consoles 17.1, 17.2 protruding outward on the casing (cf. FIGS. 2, 10, 11).

[0090] A third chassis element 7.3 is arranged under the second chassis element 7.2, which has a tubular portion 18 at the top with projections 19 of the bayonet connection 16, which complement the grooves 15.1, 15.2, on the outer circumference (cf. FIG. 3). At the bottom, the third chassis element 7.2 is provided with three legs 20.1, 20.2, 20.3 protruding downward with hooks 21.1, 21.2, 21.3 at the ends. The tubular portion 18 of the third chassis element 7.3 has an external thread 22 on the outer circumference and, above it, an outwardly protruding bearing spigot 23.

[0091] The fourth chassis element 7.4, which has an annular configuration, is arranged therebelow. The fourth chassis element 7.4 has a circumferential crosspiece 24 at the top and has multiple apertures 25.1, 25.2, 25.3 therebelow in the casing.

[0092] In order to connect to the first chassis element 7.1, the second chassis element 7.2 is pushed onto the lower portion 9.2 of the first chassis element 7.1. Here, a minimum latching between the two chassis elements 7.1, 7.2 is effective.

[0093] The third chassis element 7.3 is connected to the first and second chassis element 7.1, 7.2 via the bayonet connection 16.

[0094] The fourth chassis element 7.4 is connected by being pushed onto the legs 20.1, 20.2, 20.3 of the third chassis element 7.3 until the hooks 21.1, 21.2, 21.3 engage in the apertures 25.1, 25.2, 25.3 of the fourth chassis element 7.4.

[0095] Prior to connecting the chassis elements 7.1, 7.2, 7.3, 7.4 to one another, these can be equipped with components 4 and assemblies 5.

[0096] A hollow threaded spindle 27 is screwed from below into an internal thread 26 in the dome 12 of the first chassis element 7.1. A catch 28 having outwardly protruding catch wings 29.1, 29.2 is connected to the upper end of the threaded spindle 27 for conjoint rotation. A catch sleeve 30 is pushed onto the dome 12 from above, which has axial grooves 31.1, 31.2 on the inner circumference, which receive the catch wings 29.1, 29.2. The catch sleeve 30 has a circumferential toothing 32 externally on the lower end (cf. FIG. 1).

[0097] A lower adjusting sleeve 33 is pushed onto the catch sleeve 30 from above, which has two circumferential toothings 34.1, 34.2 of different diameter on the circumference at the bottom.

[0098] A bearing shell 35 is inserted between the lower adjusting sleeve 33 and the upper portion 9.1 of the first chassis element 7.1. An upper adjusting sleeve 36 is pressed onto the lower adjusting sleeve 33 from above or is fixedly connected thereto in another way, which upper adjusting sleeve protrudes at the top with an adjusting wheel from the first chassis element 7.1.

[0099] A lifting rod 37 is introduced from below into the threaded spindle 27, which lifting rod can be slid with a bulge-like collar 39 against the underside of the threaded spindle 27 which forms an upper stop 40.

[0100] A counter 41, a transfer unit 42 and a drive gearwheel 43 can be pushed from above onto the consoles 17.1, 17.2 of the second chassis element 7.2. The transfer unit 42 is a shaft 44, on which multiple pinions 45.1, 45.2 are arranged. The drive gearwheel 43 comprises two spur gears 46.1, 46.2 having different diameters on a common shaft 47 (cf. FIGS. 2, 5-8, 10, 11).

[0101] A bearing plate 48 having a rib 49 protruding upward in the shape of a circular arc is placed at the top on the counter 41, the transfer unit 42 and the drive gearwheel 43. Moreover, apparatuses 50 for a factory calibration are assembled on the second chassis element 7.2.

[0102] When pushing the second chassis element 7.2 onto the first chassis element 7.1, the circular arc-shaped rib 51 engages in the pocket 14. Furthermore, the pinions 45.1 and 45.2 on the transfer unit 42 come into engagement with the toothings 34.1 and 32 if the adjusting sleeves 33, 36 are arranged in their highest position. If they are displaced to their lowest position, the pinion 45.2 comes into engagement with the toothings 34.2 and 32 and the pinion 45.1 is out of engagement. This produces different gear multiplications between the adjusting sleeves 33, 36 and the catch sleeve 30.

[0103] A lower stop 51 of an overstroke system 52 is inserted into the third chassis element 7.3 from below. The lower stop 51 has outwardly protruding projections 53 which are inserted into grooves 54 on the inner circumference of the third chassis element 7.3. Furthermore, an overstroke spring 55 is inserted from below into the lower stop 51. Finally, a disk 56 is pressed from below against the overstroke spring 55, which disk has latching noses 57 protruding from the circumference, which latch into latching holes 58 on the inner circumference of the third chassis element 7.3. The disk 56 is a bearing for the overstroke spring 52 (cf. FIGS. 1, 5, 6).

[0104] The lower stop 51 and the disk 56 each have a central through-hole 59, 60 for inserting the lifting rod 37.

[0105] A display ring 61 having a circumferential toothing 62 on the upper edge is screwed onto the external thread 22 of the third chassis element 7.3. The upper edge of the display ring 61 is inclined, wherein its inclination corresponds to the pitch of the external thread 22 on the third chassis element 7.3. A drive element 63 of a crown toothing 64 is pushed onto the bearing spigot 23, which crown toothing meshes with the toothing 62 on the upper edge of the display ring 61. The drive element 63 has an internal hexagon 65 for affixing a tool for a customer calibration.

[0106] Prior to connecting the third chassis element 7.3 to the first and the second chassis element 7.1, 7.2, a bayonet spring 66, which is supported at the bottom on an inwardly protruding shoulder 67 of the third chassis element 7.3 and, at the top, presses against an inwardly protruding projection 68 of the second chassis element 7.2, is inserted from above into the third chassis element 7.3. The bayonet connection is secured in a connecting position by the bayonet spring 66.

[0107] The fourth chassis element 7.4 is connected to the third chassis element by snapping it onto the hooks on the legs of said third chassis element.

[0108] Finally, ejection apparatuses 69.1, 69.2 are placed from outside onto the preassembled chassis 3, two embodiments of which are shown in FIGS. 7 and 8.

[0109] The joined-together chassis 3 with the preassembled components 4 and assemblies 5 is pushed into the pipette housing 6 from above. The pipette housing 6 has three protruding projections 70.1, 70.2, 70.3 in the lower region on the inner circumference. The chassis 3 is pushed into the pipette housing 6 until the underside of the circumferential crosspiece of the fourth chassis element 7.4 is supported on the top of the projections 70 and the hooks 21.1, 21.2, 21.3 of the third chassis element 7.3 snap under the projections of the pipette housing. Finally, in order to secure the arrangement from below, a biasing spring 71 is inserted into the fourth chassis element 7.4, which latches on the upper end with projections in the third chassis element and supports the legs 20.1, 20.2, 20.3 internally. The biasing spring 71 additionally serves to establish a connection with a lower part of the pipette.

[0110] For the connection with a lower part of the pipette 1.1, the fourth chassis element 7.4 (lower edge coupling frame) has an inwardly protruding, circumferential shoulder 72 on the lower edge.

[0111] According to FIG. 12, the lower part 73 of the pipette has a box-like lower part chassis 74 which is formed from a front and a rear housing shell 74.1, 74.2 which are joined together in a vertical plane. The lower part 73 has a tubular connecting spigot 75 protruding upward from the upper edge of the lower part chassis 74. The connecting spigot 75 is connected in one piece to one of the two housing shells 74.1, 74.2.

[0112] In the lower part 73, eight parallel piston-cylinder apparatuses 76 are arranged in a row. Each piston-cylinder apparatus 76 has a cylinder 76.1, into which a piston 76.2, which is connected via a piston rod 76.3 to a piston disk 76.4, plunges.

[0113] At the bottom, each cylinder 76.1 is connected in one piece to a downwardly protruding spigot 77 for mounting a pipette tip on a dosing component 78. Each spigot 77 has a through-bore which is connected at the top to the internal space of the cylinder 76.1, in which the piston 76.2 can be displaced, and opens out at the bottom in an opening in the lower end of the spigot 77.

[0114] Each dosing component 78 has a circumferential projection 79 between the spigot 77 and the cylinder 76.1.

[0115] The circumferential projections 79 of the dosing components 78 are supported on the upper edges of through-holes 79 in a horizontal lower wall 80 of the lower part 73. The cylinders 76.1 are guided further up through other through-holes 81 of a horizontal support plate 82 of the lower part 73.

[0116] A spring element 83 which is embodied as a helical spring, which is supported at the bottom on the circumferential projection 79 and at the top on the lower side of the support plate 82, is guided on each cylinder 76.1.

[0117] A drive rod 84 is inserted in the connecting spigots 75, which drive rod is connected at the bottom to a cross-member 85, which has receptacles 85.1, into which the piston disks 76.4 are inserted.

[0118] The lower part 73 furthermore comprises a two-part ejector 86 which has a vertical plate-shaped ejector part 86.1, 86.2 on the lower edge, a two-part horizontal stop 86.3, 86.4 having through-openings 86.5, 86.6 open towards the front edge and an actuating element 86.7 protruding upward from the upper edge of the plate-shaped ejector part 86.1.

[0119] Details of the lower part 73 and of the two-part ejector 86 and their coupling to a pipette can be inferred from EP 2 735 369 A1, in particular paragraphs 55 and 62 to 83 as well as FIGS. 1 to 10. An alternative embodiment, which can likewise be used in the context of the present invention, is described in particular in paragraphs 91 to 98 and FIGS. 11 to 16 of the aforementioned patent. In this regard, reference is made to EP 2 735 369 A1, the contents of which are hereby incorporated into this application.

[0120] The lower part 73 can be connected to the upper part 2 of the pipette 1.1 by inserting the connecting spigot 75 into the fourth chassis element 7.4.

[0121] According to FIGS. 13 to 24, a positive displacement pipette 1.2 has a chassis 87 with components 88 and assemblies 89 connected thereto and a pipette housing 90 enclosing the chassis 87 and the components 88 and assemblies 89.

[0122] The chassis 87 comprises four tubular chassis elements 91.1, 91.2, 91.3, 91.4.

[0123] The chassis 87 has a first chassis element 91.1 at the top, which has a circumferential groove 92 on the outer circumference and, in addition, a circumferential, outwardly protruding collar 93 for the connection to a second chassis element 91.1.

[0124] The second chassis element 91.2 has, on the upper end, an inwardly protruding flange 94 for connecting to the groove 92 and collar 93 of the first chassis element 91.1. The first chassis element 91.1 and the second chassis element 91.2 can be detachably connected to one another by screwing the flange 94 into the groove 92.

[0125] The second chassis element 91.2 has, on the lower end, a slot 94 for a rotary connection to the third chassis element 91.3 which has outwardly protruding wings 95 for connecting to the slot 94 on the casing.

[0126] The third chassis element 91.3 has slots 96 on the lower end on the circumference and the fourth chassis element 91.4 has projections 97 which complement these slots for a rotary connection of the third chassis element 91.3 and fourth chassis element 91.4.

[0127] The chassis elements 91.1 to 91.4 can be equipped separately from one another with components 88 and assemblies 89. The first chassis element 91.1 can be equipped with an apparatus for adjusting the pipetting volume 98. This comprises a spindle nut 99 which can be connected to a flange and a key surface on the lower end of the first chassis element 91.1. A guide tube 100 protrudes downward from the spindle nut 99. A threaded spindle is screwed into the spindle nut 99, which threaded spindle is provided at the top with an adjusting knob 101 which protrudes from the upper end of the first chassis element 91.1. An upper housing cover 102 is fixed on the upper end of the first chassis element.

[0128] A counter 103, which is coupled to the threaded spindle via a gear mechanism, is assembled on the open side of the first chassis element.

[0129] A transmission mechanism 104 and a rotating sleeve 105 are inserted into the second chassis element 91.2. Furthermore, the transmission mechanism is connected to an actuating element 106. The second chassis element 31.2 comprises an apparatus for switching between an upward movement and a downward movement of a piston lifting rod.

[0130] Two toothed rods 108.1, 108.2, a piston lifting rod 109 having a toothing on the upper end and a gear drive 110 are mounted in the third chassis element 91.3.

[0131] Finally, a spigot 111 as well as a locking sleeve 112 and a piston ejection rod 113 are assembled in the fourth chassis element 91.4.

[0132] The preassembled assemblies are connected to one another by connecting the chassis elements 91.1 to 91.4 and the chassis 87 is installed in the pipette housing 90.

LIST OF REFERENCE NUMERALS

[0133] 1.1 Air cushion pipette [0134] 2 Upper part [0135] 3 Chassis [0136] 4 Component [0137] 5 Assembly [0138] 6 Pipette housing [0139] 7.1, 7.2, 7.3, 7.4 Chassis element [0140] 8.1, 8.2 Upper hollow cylindrical segment [0141] 8.3, 8.4 Lower hollow cylindrical segment [0142] 9.1 Upper portion [0143] 9.2 Lower portion [0144] 10 Plate [0145] 11 Through-hole [0146] 12 Dome [0147] 13 Crosspiece [0148] 14 Pocket [0149] 15.1, 15.2 Grooves [0150] 16 Bayonet connection [0151] 17.1, 17.2 Consoles [0152] 18 Tubular portion [0153] 19.1, 19.2 Projections [0154] 20.1, 20.2, 20.3 Legs [0155] 21.1, 21.2, 21.3 Hook [0156] 22 External thread [0157] 23 Bearing spigot [0158] 24 Crosspiece [0159] 25.1, 25.2, 25.3 Aperture [0160] 26 Internal thread [0161] 27 Threaded spindle [0162] 28 Catch [0163] 29.1, 29.2 Catch wing [0164] 30 Catch sleeve [0165] 31.1, 31.2 Axial grooves [0166] 32 Toothing [0167] 33 Lower adjusting sleeve [0168] 34.1, 34.2 Toothing [0169] 35 Bearing shell [0170] 36 Upper adjusting sleeve [0171] 37 Lifting rod [0172] 39 Collar [0173] 40 Upper stop [0174] 41 Counter [0175] 42 Transfer unit [0176] 43 Drive gearwheel [0177] 44 Shaft [0178] 45.1, 45.2 Pinion [0179] 46.1, 46.2 Spur gear [0180] 47 Shaft [0181] 48 Bearing plate [0182] 49 Rib [0183] 50 Apparatus for a factory calibration [0184] 51 Lower stop [0185] 52 Overstroke system [0186] 53 Projection [0187] 54 Groove [0188] 55 Overstroke spring [0189] 56 Disk [0190] 57.1, 57.2, 57.3 Latching lugs [0191] 58.1, 58.2, 58.3 Latching holes [0192] 59, 60 Through-holes [0193] 61 Display ring [0194] 62 Toothing [0195] 63 Drive element [0196] 64 Crown toothing [0197] 65 Internal hexagon [0198] 66 Bayonet spring [0199] 67 Shoulder [0200] 68 Projection [0201] 69.1, 69.2 Ejection apparatus [0202] 70 Projections [0203] 71 Biasing spring [0204] 72 Shoulder [0205] 73 Lower part [0206] 74 Lower part chassis [0207] 74.1, 74.2 Housing shell [0208] 75 Connecting spigot [0209] 76 Piston-cylinder apparatus [0210] 76.1 Cylinder [0211] 76.2 Piston [0212] 76.3 Piston rod [0213] 76.4 Piston disk [0214] 77 Spigot [0215] 78 Dosing component [0216] 79 Circumferential projection [0217] 80 Lower wall [0218] 81 Through-hole [0219] 82 Support plate [0220] 83 Spring element [0221] 84 Drive rod [0222] 85 Cross-member [0223] 85.1 Receptacle [0224] 86 Ejector [0225] 86.1, 86.2 Plate-shaped ejector part [0226] 86.3, 86.4 Horizontal stop [0227] 86.5, 86.6 Through-opening [0228] 86.7 Actuating element [0229] 87 Chassis [0230] 88 Component [0231] 89 Assembly [0232] 90 Pipette housing [0233] 91.1, 91.2, 91.3, 91.4 Tubular chassis element [0234] 92 Groove [0235] 93 Collar [0236] 94 Flange [0237] 95 Wing [0238] 96 Slot [0239] 97 Projection [0240] 98 Apparatus for adjusting the pipetting volume [0241] 99 Spindle nut [0242] 100 Guide tube [0243] 101 Adjusting knob [0244] 102 Upper housing cover [0245] 103 Counter [0246] 104 Transmission mechanism [0247] 105 Rotating sleeve [0248] 106 Actuating element [0249] 108.1, 108.2 Toothed rod [0250] 109 Piston lifting rod [0251] 110 Gear drive [0252] 111 Spigot [0253] 112 Locking sleeve [0254] 113 Piston ejection rod