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EP-4735178-A1 - MANUALLY ACTUATED SAMPLING PIPETTE COMPRISING AN ABSOLUTE VOLUME COUNTER

EP4735178A1EP 4735178 A1EP4735178 A1EP 4735178A1EP-4735178-A1

Abstract

The invention relates to a manually actuated sampling pipette (1) comprising a volume counter (22) comprising: - at least one drive gear (26) rotated by the adjustment screw (14); - a first follower gear (30a) having a number of teeth Z 1 ; - a second follower gear (30b) having a number of teeth Z 2 different from the number of teeth Z 1 ; - a first angle sensor (38a) configured to determine a first angle A 1 of the first gear (30a); - a second angle sensor (38b) configured to determine a second angle A 2 of the second gear (30b); - a system (42) for determining the angular position of the adjustment screw (14) from the pair of values (angle A 1 ; angle A 2 ).

Inventors

  • SICOT, Armand
  • DUDEK, Bruno
  • MALVOISIN, Hervé
  • MERY, Fabrice

Assignees

  • Gilson, Inc.

Dates

Publication Date
20260506
Application Date
20240627

Claims (15)

  1. 1. Manually operated sampling pipette (1) comprising a fixed pipette body (2), as well as a system (20) for adjusting the volume of liquid to be sampled, the adjustment system comprising: - a screw (14) for adjusting the volume to be sampled, centered on a screw axis (12); - a member (8) for controlling the rotation of the adjustment screw (14); - a volume counter (22) cooperating with the adjustment screw (14), characterized in that the volume counter (22) comprises: - at least one drive gear (26), driven in rotation by the adjustment screw (14); - a first follower toothed wheel (30a), meshing with said at least one drive wheel (26) and having a number of teeth Zi; - a second follower toothed wheel (30b), also meshing with said at least one drive wheel (26) and having a number of teeth Z2 preferably different from the number of teeth Zi; - a first angle sensor (38a) designed to determine a first angle Ai of the first follower gear (30a), included in the range of values [0°; 360°[; - a second angle sensor (38b) designed to determine a second angle A2 of the second follower gear (30b), included in the range of values [0°; 360°[; - a system (42) for determining the angular position of the adjustment screw (14) relative to its axis (12), this angular position being between 0 and N turns, from the pair of values (angle Ai; angle A2), the volume counter being configured so that each pair of values (angle Ai; angle A2) corresponds to a single angular position of the adjustment screw (14).
  2. 2. Pipette according to claim 1, characterized in that said at least one drive gear wheel consists of a single drive gear wheel (26) having a number of teeth Zo, the numbers of teeth Zi and Z2 being preferably each less than the number of teeth Zo, and in that the drive gear wheel (26) and the two drive gear wheels followers (30a, 30b) are preferably arranged in the same plane orthogonal to the screw axis (12).
  3. 3. Pipette according to claim 1 or 2, characterized in that the volume counter (22) comprises: - a first magnetic assembly (34a) comprising a first magnet (36a) rotationally fixed to the first follower gear wheel (30a), as well as the first magnetic angle sensor (38a), designed to determine the first angle Ai of the first follower gear wheel (30a), corresponding to the angle of the first magnet, included in the range of values [0°; 360°[; - a second magnetic assembly (34b) comprising a second magnet (36b) rotationally fixed to the second follower gear wheel (30b), as well as the second magnetic angle sensor (38b), designed to determine the second angle A2 of the second follower gear wheel (30b), corresponding to the angle of the second magnet, included in the range of values [0°; 360°[ .
  4. 4. Pipette according to claim 3, characterized in that the first and second angle sensors (38a, 38b) are each designed to measure the angle of the magnetic field of the associated magnet (36a, 36b), in a measuring plane of the sensor.
  5. 5. Pipette according to claim 3 or 4, characterized in that each of the first and second magnets (36a, 36b) is concentric with its associated angle sensor (38a, 38b), and/or in that the spacing between each of the first and second magnets (36a, 36b) and its associated angle sensor (38a, 38b) is of the order of 1 mm.
  6. 6. Pipette according to any one of the preceding claims, characterized in that the numbers of teeth Zi, Zz are relatively prime, and in that the difference between these two numbers of teeth Zi, Zj is preferably equal to one.
  7. 7. Pipette according to any one of the preceding claims combined with claim 2, characterized in that the volume counter (22) is designed so that the number of turns N of the adjustment screw (14), and the numbers of teeth Zo, Zi, Z2, satisfy the following formula:
  8. 8. Pipette according to any one of the preceding claims combined with claim 2, characterized in that the number of turns N of the screw is twelve, the number of teeth Zo is thirty-five, the number of teeth Zi is twenty, and the number of teeth Z2 is twenty-one.
  9. 9. Pipette according to any one of the preceding claims combined with claim 3, characterized in that each of the first and second magnets (36a, 36b) is fixed on a face of its associated follower wheel (30a, 30b), extending orthogonally or substantially orthogonally to an axis of rotation (32a, 32b) of this follower wheel.
  10. 10. Pipette according to claim 9, characterized in that each of the first and second magnets (36a, 36b) is a cylindrical magnet of diametrical magnetization, and the axis of the cylinder of which crosses orthogonally or substantially orthogonally a measurement plane of the associated sensor (38a, 38b).
  11. 11. Pipette according to any one of the preceding claims combined with claim 2, characterized in that the drive gear wheel (26) is arranged centered around the adjustment screw (14).
  12. 12. Pipette according to any one of the preceding claims, characterized in that it comprises a pipetting control rod (10) integral in rotation with the adjustment screw (14) of the volume to be sampled, the rotation control member of the adjustment screw being a control button (8) integral in rotation with the end of the control rod (10).
  13. 13. 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 in that it is preferably designed so as to allow at least one of the following actions: - data collection; - transmission of data to the outside; - receiving data from outside.
  14. 14. Pipette according to any one of the preceding claims, characterized in that said system (42) for determining the angular position of the adjustment screw (14) relative to its axis, from the pair of values (angle Ai; angle A2), comprises a calculator (44).
  15. 15. Method for determining a volume to be taken from a manually operated sampling pipette (1) according to any one of the preceding claims, characterized in that it comprises a step of determining the angular position of the adjustment screw (14) relative to its axis (12), from the pair of values (angle Ai; angle A2).

Description

DESCRIPTION TITLE: MANUALLY OPERATED SAMPLING PIPETTE INCLUDING AN ABSOLUTE VOLUME COUNTER TECHNICAL AREA The present invention relates to the field of single-channel or multi-channel sampling pipettes, also called laboratory pipettes, or air-displacement or positive-displacement liquid transfer pipettes, intended for the calibrated sampling and introduction of liquid into containers. More specifically, the invention relates to manually operated sampling pipettes, intended to be held in the hand by an operator during liquid sampling and dispensing operations. The invention relates more particularly to the means used to adjust the volume of liquid to be taken. STATE OF PRIOR ART Conventional pipettes have a volume adjustment screw to be taken, which is controlled in rotation by a pipette control knob, via a control rod connecting this knob to the volume adjustment screw. Other volume adjustment solutions are known, such as an adjustment wheel not connected to the pipette control rod. The most common counter on hand-operated pipettes is based on a mechanical design, driven by the rotation of the adjustment screw. For example, the counter includes three drums marked from 0 to 9, each allowing a single digit to be displayed through a slot. The lower drum is secured to the rotation of the screw by a key that moves in a slot in the adjustment screw. The screw can therefore translate, which modifies the upper stop of the pipette, but only its rotation is perceived by the counter. To count multiple turns of the screw, the bottom drum drives the middle drum via a ratchet mechanism, which allows the middle drum to turn one tenth of a turn when the bottom drum goes from 9 to 0, after completing a full turn. The same mechanism is used between the middle drum and the top drum. Thus, the counter can count one hundred turns, before returning to its initial state. Usually, out of these one hundred turns, only ten to fifty are used, depending on the pipette model. On each of the drums, dashes are added between the numbers, thus making it possible to distinguish one hundred nuances on each drum, thus increasing the precision of the pipette. This results in a resolution of the mechanical counter of the order of 3.6°, or +/- 1.8°. This resolution is adequate, but it remains improvable. Consequently, one of the primary aims of the present invention lies in improving the design of the pipette and its volume counter, so as to increase its resolution. Another aim lies in improving the ergonomics of adjusting the volume and reading it on the pipette screen. STATEMENT OF THE INVENTION To meet this aim, the invention relates to a manually operated sampling pipette comprising a fixed pipette body, as well as a system for adjusting the volume of liquid to be sampled, the adjustment system comprising: - a screw for adjusting the volume to be sampled, centered on a screw axis; - a control member for rotating the adjustment screw; - a volume counter cooperating with the adjustment screw, characterized in that the volume counter comprises: - at least one drive gear, rotated by the adjustment screw; - a first follower toothed wheel, meshing with said at least one drive wheel and having a number of teeth Zi; - a second follower toothed wheel, also meshing with said at least one drive wheel and having a number of teeth Z2 preferably different from the number of teeth Zi; - a first angle sensor designed to determine a first angle Ai of the first follower gear, within the range of values [0°; 360°[; - a second angle sensor designed to determine a second angle A2 of the second follower gear, within the range of values [0°; 360°[; - a system for determining the angular position of the adjustment screw relative to its axis, this angular position being between 0 and N turns, from the pair of values (angle Ai; angle A2), the volume counter being configured so that each pair of values (angle Ai; angle A2) corresponds to a single angular position of the adjustment screw. The design proposed by the present invention differs radically from those known for manually operated pipette counters. The accuracy and resolution of the counter are greatly increased compared to the existing ones. For example, the accuracy can be of the order of +/- 1°, and resolution of the order of +/- 0.005°, all with high reliability and low power consumption. Furthermore, the principle specific to the invention makes it possible to give a correct result, even after a power supply fault. It also allows possible integration in a limited space, such as that encountered in a manually operated sampling pipette. Indeed, the proposed invention makes it possible to obtain both an absolute count of the number of turns of the screw, and significant precision, without using a mechanism with a high reduction ratio. The solution therefore takes up little space and remains very simple mechanically, implying a low manufacturing cost of the assembly. The volume counter according to the inven