Manually actuated sampling pipettor with absolute volume counter

Abstract

The invention relates to a manually actuated sampling pipette (1) comprising a volumeter (22) comprising:-at least one drive gear (26) rotated by an adjustment screw (14); a first driven gear (30a) having a number of teeth Z1; a second driven gear (30b) having a number of teeth Z2, the number of teeth Z2 being different from the number of teeth Z1; -a first angle sensor (38a) configured to determine a first angle A1 of the first driven gear (30a); -a second angle sensor (38b) configured to determine a second angle A2 of the second driven gear (30b); a system (42) for determining the angular position of the adjustment screw (14) from the pairs of values (angle A1; angle A2).

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of single or multi-channel sampling pipettes, also known as laboratory pipettes, or air displacement or positive displacement liquid transfer pipettes, for calibrating a sample and introducing a liquid into a container.

[0002] More precisely, the present invention relates to manually actuated sampling pipettes, for use by an operator in hand during liquid sampling and dispensing operations.

[0003] The present invention more particularly relates to a device for adjusting the volume of liquid to be sampled. BACKGROUND

[0004] Conventional pipettes are provided with a screw for adjusting the volume of the sample, which is adjusted by rotation using a control knob on the pipette, the control knob being connected to the volume adjustment screw by a control lever. Other volume adjustment solutions exist, such as the use of an adjustment gear not connected to the pipette control lever.

[0005] The most common gauge on manually actuated pipettes is based on a mechanical design driven by the rotation of the adjustment screw. For example, this gauge comprises three drums marked from 0 to 9, each drum displaying a digit by a slot. The bottom drum is integral with the screw by a key that moves in the slot of the adjustment screw. The screw can thus be translated, changing the position of the top abutment of the pipette, but the gauge can only perceive the rotation of the screw.

[0006] In order to count the number of revolutions of the screw, the bottom drum drives the intermediate drum by a ratchet mechanism. When the bottom drum completes a full rotation from 9 to 0, the intermediate drum rotates a tenth of a revolution. The same mechanism is used between the intermediate drum and the top drum. The gauge can thus count one hundred revolutions and then return to the initial state. Usually, only ten to fifty of these one hundred revolutions are used, depending on the model of the pipette.

[0007] On each drum, a short bar is added between the digits, so that one hundred graduations can be distinguished on each drum, thus increasing the accuracy of the pipette. This makes the resolution of the mechanical gauge of the order of 3.6°, or even + / - 1.8°.

[0008] This resolution is still acceptable, but there is room for improvement. One of the main objectives of the present invention is thus to improve the design of the pipette and its volume gauge, in order to increase its resolution. Another objective is to improve the ergonomics of the volume adjustment and reading operation on the screen of the pipette. SUMMARY

[0009] To achieve this, one object of the application is to provide a manually actuated sampling pipette comprising a fixed pipette body and an adjustment system for adjusting the volume of liquid to be sampled, the adjustment system comprising:

[0010] - a screw for adjusting the volume to be sampled, centered on a screw axis;

[0011] - a rotation control member of the adjustment screw;

[0012] - a volume counter cooperating with the adjustment screw,

[0013] characterized in that the volume counter comprises:

[0014] - at least one drive gear, rotatably driven by the adjustment screw;

[0015] - a first driven gear, meshing with said at least one drive gear and having a number of teeth Z1 ;

[0016] - a second driven gear, also meshing with said at least one drive gear and having a number of teeth Z2, the number of teeth Z2 being preferably different from the number of teeth Z1 ;

[0017] - a first angle sensor designed to determine a first angle Al of the first driven gear, ranging in value between [0°; 360°[

[0018] - a second angle sensor designed to determine a second angle A2 of the second driven gear, ranging in value between [0°; 360°[

[0019] - a system for determining the angular position of the adjustment screw relative to its axis, between 0 and N turns, by the numerical pair (angle Al ; angle A2), the volume counter being configured so that each numerical pair (angle Al ; angle A2) corresponds to a single angular position of the adjustment screw.

[0020] The design provided by the application is quite different from known manually actuated pipette counters. The accuracy and resolution of the counter are significantly improved compared to existing products. For example, it can have an accuracy of the order of + / - 1° and a resolution of the order of + / - 0.005°, with high reliability and low energy consumption.

[0021] In addition, the principle specific to the application makes it possible to give correct results even after a power failure.

[0022] It also allows integration in limited spaces, for example in a manually actuated sampling pipette. Indeed, the application makes it possible to achieve an absolute counting of the number of turns of the screw, with high accuracy, without using a mechanism with a high reduction ratio. The solution therefore occupies little space and has a very simple mechanical structure, which reduces the manufacturing cost of the assembly.

[0023] The volumetric meter described in the present application also has the advantage of being able to easily replace the conventional mechanical meter in existing pipette devices.

[0024] It is worth noting that the present application can employ more than two driven gears, in order to further increase the precision and / or resolution and / or the number of rotatable turns of the adjustment screw, although this can result in an increase in the overall size. However, even with only two driven gears, by choosing their number of teeth appropriately, very large numbers of rotatable turns can be encoded.

[0025] Finally, it is noted that the relationship between the number of turns of rotation (corresponding to the angular position determined for the adjustment screw) and the volume of sample can be obtained in a conventional manner, depending on the characteristics of the pipette itself on which the electronic meter is installed, i.e. the diameter of the piston and the pitch of the screw. Calibration data, and in some cases data on environmental conditions, can also be used to participate in the determination of the volume of sample.

[0026] The present application preferably has at least one of the following optional features, which can be used individually or in combination.

[0027] Preferably, the at least one drive gear consists of a single drive gear having a number of teeth Z0, the numbers of teeth Z1 and Z2 are preferably each less than the number of teeth Z0, and the drive gear and the two driven gears are preferably arranged on the same plane orthogonal to the screw axis.

[0028] Alternatively, the numbers of teeth Z1 and Z2 can be greater than the number of teeth Z0.

[0029] Another solution is to provide, for example, two drive gears instead of one, which are each engaged with two driven gears. In the latter case, the gears can be arranged two by two on different parallel planes, thus saving overall size in the transverse direction of the pipette. It is worth noting that in this solution, the numbers of teeth of the two drive gears can be different or the same. If they are different, the numbers of teeth Z1 and Z2 of the two driven gears can also be different or the same.

[0030] Preferably, the volumetric meter comprises:

[0031] - a first magnetic assembly comprising a first magnet rotating integrally with the first driven gear, and a first angular magnetic sensor designed so as to determine a first angle Al of the first driven gear, which corresponds to the angle of the first magnet, which takes values in the range [0°; 360°[

[0032] - a second magnetic assembly comprising a second magnet rotating integrally with a second driven gear, and a second angular magnetic sensor designed so as to determine a second angle A2 of the second driven gear, which corresponds to the angle of the second magnet, the value of which ranges from [0°; 360[°].

[0033] However, even if the angular sensors are preferably of the magnetic type as described above, these sensors can take different designs, for example optical, capacitive, etc.

[0034] Preferably, the first and second angular sensors are each designed to measure the angle of the magnetic field of the associated magnet in the plane of the sensor.

[0035] Thus, strictly speaking, such a sensor is not a magnetometer, since it does not measure the intensity of the magnetic field, but only the angle of the magnetic field, with high resolution. The resolution is higher when the sensor is close to the magnet and when the magnetic moment of the magnet is large.

[0036] Preferably, the first and second magnets are concentric with their associated angular sensor, and / or the distance between the first and second magnets and their associated angular sensor is approximately 1 mm.

[0037] These preferred data make it possible to obtain the best results in terms of accuracy and / or resolution.

[0038] Preferably, the numbers of teeth Z1 and Z2 are coprime, and the difference between these two numbers of teeth Z1 and Z2 is preferably equal to 1.

[0039] When the two numbers of teeth Z1 and Z2 are coprime, it is possible to make the angular offset between the two magnets small with respect to the number of teeth, and thus to encode a large number of revolutions of the screw while keeping a small overall size. Furthermore, when the difference between the two numbers of teeth is 1, it means that the two driven gears are of similar size, which makes it easier to install them in a pipette.

[0040] Preferably, the volumeter is designed so that the number of revolutions N of the screw and the numbers of teeth Z0, Z1, Z2 satisfy the following formula:

[0041]

[0042] It should be noted that the ideal combination is not necessarily the one that makes it possible to encode the maximum number of revolutions of the screw. Indeed, the number of teeth of the driven gears should be able to encode the number of revolutions of the screw required, but ideally should not exceed this number in order to obtain the highest resolution in the effective range.

[0043] In this respect, it should be noted that, according to this formula:

[0044] - Z0, i.e. the number of teeth of the drive gear, which tends to reduce the number of revolutions N of the adjustment screw that can be encoded;

[0045] - the maximum number of rotations N that can be encoded generally increases as the product of Z1 and Z2 increases;

[0046] - the term |Z2-Z1| in the denominator indicates that, in order to encode a large number of rotations N by limiting the number of teeth, the difference between the number of teeth Z1 and Z2 must be as small as possible, so it is preferable for the difference to be one tooth.

[0047] Preferably, the number of rotations N of the screw is 12, the number of teeth Z0 is 35, the number of teeth Z1 is 20 and the number of teeth Z2 is 21.

[0048] The combination of these preferred values corresponds to an optimized solution that meets a number of criteria, including:

[0049] - the size of the gear teeth is not too small (for example, the "module" is greater than 0.3 or 0.35), so as to facilitate the consideration of cast parts and to allow the presence of gear play;

[0050] - the inner diameter of the drive gear is greater than a given value, for example 10 mm, so that the adjustment screw can pass through;

[0051] - the maximum overall size of the three gears is kept below a given limit value, for example, it is inscribed in a circle with a maximum radius of 14 mm, to adapt to the installation space of the gauge in the pipette.

[0052] It should be noted that in all cases, the maximum number of rotations N is not necessarily an integer, but can be a rational number.

[0053] Preferably, the first magnet and the second magnet are attached to the face of the associated driven gear, respectively, extending orthogonally or substantially orthogonally to the rotation axis of the driven gear.

[0054] Preferably, the first magnet and the second magnet are both radially magnetized cylindrical magnets, and the axis of the cylinder passes orthogonally or substantially orthogonally through the measurement plane of the associated sensor.

[0055] Preferably, the drive gear is arranged so as to be centered on the adjustment screw.

[0056] This makes it possible to reduce the volume of the gauge, making it easier to install in the pipette. However, other solutions can also be considered, but these solutions have a larger overall size.

[0057] Preferably, the pipette comprises a pipetting control lever that rotates integrally with the adjustment screw of the volume to be sampled, the rotation control member of the adjustment screw being a control knob rotatably fixed at one end of the control lever.

[0058] Alternatively, the system for adjusting the volume to be sampled can comprise a control gear not connected to the pipetting control lever, or any other type of adjustment system known to the person skilled in the art, without departing from the scope of the application.

[0059] Preferably, the volume adjustment system comprises a display, preferably for displaying the volume adjusted or being adjusted, or more generally for displaying data, and the adjustment system is preferably designed to be able to perform at least one of the following operations:

[0060] - data collection;

[0061] - external data transmission;

[0062] - reception of data from the outside.

[0063] Preferably, the system for determining the angular position of the adjustment screw relative to its axis from the numerical pair (angle Al; angle A2) comprises a calculator.

[0064] Another object of the application is to provide a method for determining the volume to be sampled from a manually actuated pipette for sampling according to the description below, comprising the step of determining the angular position of the adjustment screw relative to its axis from the numerical pair (angle Al; angle A2).

[0065] Other advantages and features of the application will be set out in the following non-limiting detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0066] The application will be described with reference to the accompanying drawings, in which:

[0067] [ Figure 1 ] is a front view of a manually actuated pipette for sampling according to the application;

[0068] [ Figure 2 ] is a partial perspective view of the pipette shown in the previous figure;

[0069] [ Figure 3 ] is a perspective view of a system for adjusting the volume of liquid to be sampled according to a preferred embodiment of the application;

[0070] [ Figure 4 ] is a perspective view of a part of the adjustment system shown in the previous figure, installed in the pipette;

[0071] [ Figure 5 ] is a perspective view similar to the previous figure, showing the volume gauge of the adjustment system shown in the previous figure in more detail;

[0072] [ Figure 6 ] is a perspective cross-sectional view of a part of the pipette, with the volume gauge exposed;

[0073] [ Figure 7 ] is a cross-sectional view of the main elements of the volumeter;

[0074] [ Figure 8 ] is a graph showing the respective angular position of the two driven gears of the volumeter shown in the previous figure as a function of the number of revolutions of the driving gear of the volumeter. DETAILED DESCRIPTION

[0075] Reference is first made to Figure 1 , in which a single-channel or multi-channel type manual actuation sampling pipette 1 is shown.

[0076] The pipette 1, also known as an air displacement or positive displacement pipette, here manual, comprises an upper fixed body 2 forming a handle and a lower part 4, the lower end of which integrates a sampling cone holding tip (not shown). This tip is used to hold a cone, also known as consumable, and is ejected from the tip by an ejection system 6 after completion of the pipetting operation. However, other ejection systems different from that shown in Figure 1 may be considered without departing from the scope of the invention.

[0077] The pipette 1 comprises a control knob 8, actuated by the thumb of the operator, which makes it possible to carry out different pipetting operations, such as sampling and dispensing. The knob 8 is mounted at the top end of a pipetting control rod 10, which is intended to translate along the longitudinal central axis 12 of the pipette during the pipetting steps described above. Preferably, the knob 8 rotates integrally with the control rod 10, in addition, the lower end of the control rod 10 cooperates with a screw 14 for adjusting the volume to be sampled, as shown in Figure 2 . This cooperation makes the control rod 10 rotate integrally with the screw 14, the axes of which are preferably coincident and preferably correspond to the longitudinal central axis 12 of the pipette.

[0078] The adjustment screw 14 for adjusting the volume to be sampled is part of a liquid volume adjustment system 20 specific to the invention, a preferred embodiment of which will be described with reference to Figures 2 to 8 .

[0079] First of all, it should be noted that the rotation of the adjustment screw 14, by known means, causes it to translate along the axis 12 and possibly to cause the translation of other components, thus axially moving a piston located in a liquid chamber in the bottom 4 of the pipette. It is by adjusting the top position of this piston that the subsequent sampling volume during pipetting is affected. In fact, the relationship between the number of revolutions of the screw 14 and the knob 8 and the sampling volume depends on the characteristics of the pipette 1, in particular the diameter of the piston and the pitch of the screw 14. Calibration data or environmental condition data can also contribute to determining the sampling volume.

[0080] In addition to the adjustment screw 14, the volume adjustment system 20 comprises a control knob 8 and a control lever 10, as well as an absolute volume meter 22, preferably of magnetic design. The system also preferably comprises a digital display 24 for displaying the adjusted volume value through the window 7 on the handle 2. Here, the display 24 preferably adopts a four-digit display, so that the magnetic volume meter is referred to as a "four-digit" volume meter. This volume meter has a very high precision compared to existing volume meters. It is to be noted that, as will be described below, the display can also display other information in addition to the volume, such as the status of the pipette, the battery level, the number of cycles, the number of calibrations, the date, or even data from internal / external sensors, such as the temperature, etc.

[0081] The system 20 also comprises other elements, which are shown in a schematic form in the figures and are associated with the reference 25, such as a battery, a wireless charging system, a (wired or wireless) communication module for the computer hardware remotely connected to the pipette, etc.

[0082] The volume adjustment system 20 can be easily implanted in an existing manually actuated pipette, which is preferably designed to allow the collection of data, in particular pipetting data such as the number of pipetting cycles, the sampled volume, the operating conditions, etc., while also ensuring the transmission of these data to the outside and / or the reception of data from the outside.

[0083] The magnetic volume meter 22 first comprises a gear system equipped with a drive gear 26 centered on the axis 12 and directly rotatably driven by the adjustment screw 14. For example, the drive is achieved by means of a lug 27 protruding inwardly from the gear 26, which is housed in a longitudinal groove 28 of the screw 14, as shown in Figure 6 and Figure 7 The drive gear 26 has a number of teeth Z0, which here preferably corresponds to 35 teeth. Its inner diameter is preferably greater than 10 mm in order to allow the screw 14 to pass through and slide with respect to this drive gear 26, which remains translationally fixed with respect to the axis 12.

[0084] The drive gear 26 meshes with a first driven gear 30a, which has a number of teeth Z1, preferably 20 teeth. The drive gear 26 also meshes with a second driven gear 30b, which has a number of teeth Z1, preferably 21 teeth. In all cases, the number of teeth Z2 is different from the number of teeth Z1, and both are preferably less than the number of teeth Z0. Furthermore, the numbers of teeth Z1 and Z2 preferably differ by only one tooth.

[0085] The three gears 26, 30a, 30b are preferably arranged in the same transversal plane of the pipette, orthogonal to the axis 12. Their overall dimensions are such that the assembly formed by the three gears can be housed in a circle of limited radius, preferably less than 14 mm, so as to facilitate its installation in the hollow fixed body 2 of the pipette.

[0086] The rotation axes 32a, 32b of the driven gears 30a, 30b are therefore parallel to the central axis 12 about which the drive gear 26 is centered.

[0087] The volumeter 22 also comprises a first magnetic assembly 34a, which comprises a first magnet 36a rotating integrally with the first driven gear. Preferably, the first magnet 36a is attached to an axial end face of the first driven gear 30a, and it is a cylindrical magnet, preferably a radially magnetized disc, the cylindrical axis of which corresponds to the rotation axis 32a of the gear 30a. For example, the disc-shaped magnet 36a can be housed in a recess in the upper face of the gear 30a, as shown in the figures. The first assembly 34a also comprises a first magnetic angle sensor 38a, which is intended to determine a first angle Al of the first driven gear, which here corresponds to the angle of the first magnet 36a, which takes values in the range [0°; 360°[.

[0088] The axis 30a of the first cylindrical magnet 36a therefore passes orthogonally or substantially orthogonally through the measurement plane of the first angle sensor 38a, which is inscribed in this measurement plane, and which also corresponds to a transversal plane of the pipette. The magnet 36a and its associated sensor 38a are arranged concentrically, and in the axial direction of the pipette, the spacing between the first magnet 36a and the measurement plane of the first angle sensor 38a is approximately 1 mm.

[0089] The first angle sensor 38a is designed so as to measure the angle Al of the magnetic field of the magnet 36a in the sensor measurement plane, which is parallel to the transversal plane of the pipette. Figure 7 The sensor 38a therefore does not measure the magnetic field intensity of the magnet 36a, but only the angle Al thereof with respect to a reference, also called zero angle of the sensor, in Figure 7 In the present invention, the resolution of the sensor 38a is higher when it is close to the magnet.

[0090] The volumeter 22 also comprises a second magnetic assembly 34b, which is identical or similar to the first magnetic assembly 34a described previously. In the figures, therefore, the elements of the second magnetic assembly 34b have the same reference numbers as the elements of the first magnetic assembly 34, except that the "a" has been replaced by "b".

[0091] The second magnet 36b and the second magnetic angle sensor 38b are thus designed to determine a second angle A2 of the second driven gear 30b, which corresponds to the angle of the second magnet and which takes values in the range [0°; 360°[. Likewise, the sensor 38b here does not measure the magnetic field strength of the magnet 36b, but only the angle A2 thereof relative to a reference, also referred to as the zero angle of the sensor, in Figure 7 the present case marked R2.

[0092] It is noted that the two magnets 36a, 36b are preferably located in the same transverse plane of the pipette, and that the two magnetic sensors 38a, 38b are also located in the same transverse plane of the pipette, which are both supported by the printed circuit 40 integral with the pipette body.

[0093] The magnetic volumetric meter 22 further comprises a system 42 for determining the angular position of the adjustment screw 14 relative to its axis 12. The system 42 is schematically shown in Figure 7 Fig. 4 and preferably comprises a calculator 44 designed to determine the angular position of the screw 14 from the numerical pair (angle Al; angle A2). For this purpose, the printed circuit 40 can be part of this determination system 42 and provide the numerical pair (angle Al; angle A2) from which the angular position Pa of the adjustment screw 14 can be determined.

[0094] The angular position Pa of the screw is between 0 and N turns, where N is not necessarily an integer number, but can be a rational number. In the design described above, each numerical pair (angle Al; angle A2) corresponds to a single angular position Pa of the adjustment screw 14. For example, the angular position Pa can be expressed as 5 turns and 250°, 7 turns and 75°, 11 turns, etc. It has extreme values corresponding to N (integer or rational number) which can be determined by the following formula:

[0095]

[0096] The N value corresponding to the number of teeth described above is thus equal to twelve turns. This means that during the twelve turns of rotation of the screw 14 and the drive gear 26, the values of the numerical pair (angle Al; angle A2) are always different and thus correspond to a single angular position Pa. Only after completing the twelfth turn of rotation, the numerical pair is the same as the one observed before the screw started rotating, i.e. its extreme relative position. Figure 8 The course of the angles Al and A2 during the rotation of the screw 14 and the drive gear 26 is shown in Fig. 4. In the figure, the thickest dashed line represents the values of the angle Al and the thinnest dashed line represents the values of the angle A2. The two curves clearly show that at each moment of time during the twelve turns of rotation of the screw, the numerical pair (angle Al; angle A2) is always unique and different. In order to facilitate understanding, the curves are represented by dashed lines, and the visible solid lines only represent the transition from one rotation to the next of each driven gear 30a, 30b.

[0097] Once the values ​​(angle A1; angle A2) are known and passed to system 42, a person skilled in the art can configure system 42 in any manner they deem appropriate to obtain a single corresponding value for the angular position Pa of screw 14. This determination process can be implemented, for example, through a pre-established mapping table that shows the relationship between the angular position of screw 14 (expressed in whole revolutions and degrees) and the changes in the identified numerical pairs (angle A1; angle A2).

[0098] Another method is to use a calculator 44 to calculate the positive difference "Dp" between the two angle values ​​of the numerical pair (angle A1; angle A2). To do this, when the difference between the values ​​of angle A1 and angle A2 is negative, add 360° to the value of angle A1.

[0099] Then, calculator 44 can calculate the angular position Pa of the screw using the following formula:

[0100] Pa = Dp * N / 360

[0101] For example, when the angular difference "Dp" is 180°, the angular position Pa calculated according to the previous formula is 6 revolutions. Figure 8 This is also shown in the chart. Six rotations of the screw correspond to a single volume of liquid to be sampled, and that volume is then displayed on the monitor 24.

[0102] The calculator 44 can perform other calculations to obtain a more accurate value for the actual angular position Pa of the adjusting screw 14. Furthermore, it can be configured to calculate and provide a confidence index each time the actual angular position Pa of the adjusting screw 14 is determined. This confidence index can be displayed, and an alarm can be triggered to the user when the index falls below a threshold.

[0103] For example, the Pa value determined by the above formula can be refined using various data, such as the measured values ​​of two angles A1 and A2 and / or data related to gear kinematics.

[0104] For example, earlier in the process of determining the angular position Pa of the adjusting screw 14, magnetic compensation calculations can be performed to determine the two angle values ​​A1 and A2. More precisely, this compensation calculation can correct the values ​​of the two angles A1 and A2 measured by sensors 38a and 38b to account for the cross-influence of the first magnet 36a on the second sensor 38b, and vice versa.

[0105] In particular, to determine the above-mentioned influence, it is necessary to take into account the direction and intensity of the magnetic field measured from the opposite magnet, to calculate the angular offset caused by the opposite magnet and then to add or subtract the angular value measured by each sensor using the offset. The values of the two angles Al and A2, once corrected, are closer to the values measured in the absence of the opposite magnet, thus improving the measurement accuracy of the angles of the driven gears 30a and 30b.

[0106] In all cases, the designs provided offer a particularly high volumetric accuracy and resolution, on the order of + / - 1° and + / - 0.005°, respectively, while at the same time conferring high reliability on the volumeter.

[0107] Moreover, thanks to the simplification of the calibration procedure, the design also simplifies the assembly process when manufacturing the electronic meter. The calibration procedure can simply consist of rotating 12 turns to collect data, then using all of this data to perform calculations to optimally adjust the relevant parameters to maximize the measurement accuracy of the electronic meter. Thus, the way the magnets are glued and the gears are mounted can be adjusted flexibly, thus simplifying the assembly of the electronic meter before it is installed on the sampling pipette.

[0108] Finally, it should be noted that conventional mechanical pipettes can only be calibrated at one point. To do this, it is necessary to find the right position of the top of the lever abutment so that the display value of the meter coincides with the volume actually taken up and dispensed by the pipette. The limitation of this calibration method is that if the accuracy curve (corresponding to the difference between the volume taken up and the adjusted volume) has a slope, then difficulties can be encountered during calibration, making it difficult to guarantee that the pipette will meet the requirements over its entire range.

[0109] Conversely, with the absolute meter implemented in the present invention, since the calculator 44 can correct the volume display to maintain a minimum accuracy error over the entire range, the calibration of the pipette equipped with said meter is simpler and more accurate.

[0110] Of course, the person skilled in the art can make various modifications to the above-described invention, which are described as non-limiting examples, the scope of the invention being defined by the attached claims.

Claims

1. A manually actuated sampling pipette (1) comprising a fixed pipette body (2) and a system (20) for adjusting the volume of liquid to be sampled, said adjustment system comprising: - a screw (14) for adjusting the volume to be sampled, centered on a screw axis (12); - a rotation control member (8) of said adjustment screw (14); - a volumeter (22) cooperating with said adjustment screw (14), characterized in that said volumeter (22) comprises: - at least one drive gear (26) rotatably driven by said adjustment screw (14); - a first driven gear (30a) meshing with said at least one drive gear (26) and having a number of teeth Z1; - a second driven gear (30b) also meshing with said at least one drive gear (26) and having a number of teeth Z2, preferably different from said number of teeth Z1; - a first angle sensor (38a) for determining a first angle Al of said first driven gear (30a), ranging in the interval [0°; 360°[ - a second angle sensor (38b) for determining a second angle A2 of said second driven gear (30b), ranging in the interval [0°; 360°[ - a system (42) for determining, from the numerical pair (angle Al; angle A2), the angular position of said adjustment screw (14) relative to its axis (12), ranging between 0 and N turns, said volumeter being configured so that each numerical pair (angle Al; angle A2) corresponds to a single angular position of said adjustment screw (14).

2. The pipette of claim 1, wherein, Said at least one drive gear consists of a single drive gear (26) having a number of teeth Z0, the number of teeth Z1 and the number of teeth Z2 being preferably both smaller than the number of teeth Z0, and said drive gear (26) and the two driven gears (30a, 30b) are preferably disposed on a same plane orthogonal to said screw axis (12).

3. The pipette according to claim 1 or 2, characterized in that Said volumeter (22) comprises: - a first magnetic assembly (34a) comprising a first magnet (36a) rotating integrally with said first driven gear (30a), and a first magnetic angle sensor (38a) for determining said first angle Al of said first driven gear (30a), said first angle corresponding to the angle of said first magnet, ranging in the interval [0°; 360°[ - a second magnetic assembly (34b) comprising a second magnet (36b) rotating integrally with said second driven gear (30b), and a second magnetic angle sensor (38b) for determining said second angle A2 of said second driven gear (30b), said second angle corresponding to the angle of said second magnet, ranging in the interval [0°; 360°[ 4. The pipette of claim 3, wherein, Said first and second angle sensors (38a, 38b) are each designed for measuring the angle of the magnetic field of its associated magnet (36a, 36b) in the measurement plane of the sensor.

5. The pipette according to claim 3 or 4, characterized in that The first and second magnets (36a, 36b) are each concentric with the angular sensor (38a, 38b) associated therewith, and / or the spacing between the first and second magnets (36a, 36b) and the angular sensor (38a, 38b) associated therewith is approximately 1 mm.

6. The pipette according to any one of the preceding claims, characterized in that The number of teeth Z1 and the number of teeth Z2 are coprime, and the difference between these two numbers of teeth Z1 and Z2 is preferably 1.

7. The pipette according to any of the preceding claims in combination with claim 2, characterized in that, The volume meter (22) is designed such that the number of rotations N of the adjusting screw (14) and the number of teeth Z0, the number of teeth Z1, the number of teeth Z2 satisfy the following formula: .

8. The pipette according to any of the preceding claims in combination with claim 2, characterized in that, The number of turns N of the adjustment screw is 12, the number of teeth Z0 is 35, the number of teeth Z1 is 20, and the number of teeth Z2 is 21.

9. The pipette according to any of the preceding claims in combination with claim 3, characterized in that, The first and second magnets (36a, 36b) each extend along an axis (32a, 32b) orthogonal or substantially orthogonal to the rotation axis of the driven gear, on the face of the driven gear (30a, 30b) associated therewith.

10. The pipette of claim 9, wherein, The first and second magnets (36a, 36b) are each radially magnetized cylindrical magnets, and the axis of the cylinder thereof passes orthogonally or substantially orthogonally through the measurement plane of the associated sensor (38a, 38b).

11. The pipette according to any of the preceding claims in combination with claim 2, characterized in that, The drive gear (26) is arranged concentrically to the adjustment screw (14).

12. The pipette according to any one of the preceding claims, characterized in that The pipette comprises a pipette control lever (10) which rotates integrally with the adjustment screw (14) of the volume to be sampled, the rotation control member of which is a control knob (8) which is rotationally fixed at one end of the control lever (10).

13. The pipette according to any one of the preceding claims, characterized in that The volume adjustment system (20) comprises a display (24) for displaying the volume and / or data, and is preferably designed to be able to perform at least one of the following operations: - data collection; - external data transmission; - reception of data from the outside.

14. The pipette according to any one of the preceding claims, characterized in that The system (42) for determining the angular position of the adjustment screw (14) relative to its axis from the numerical pair (angle Al; angle A2) comprises a calculator (44).

15. A method of determining the volume to be sampled from a manually actuated sampling pipette (1) according to any one of the preceding claims, characterized in that The method comprises a step of determining the angular position of the adjustment screw (14) relative to its axis (12) from the numerical pair (angle Al; angle A2).

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