EP3200923A1 - Sampling pipette having an ergonomic control button - Google Patents

Abstract

The invention relates to an assembly (3) for an ergonomic sampling pipette including a control rod (10) at the end of which is arranged a control button (12) for controlling the movement of the control rod (10) along a longitudinal axis (18) thereof, the button (12) having a pressure surface (11) for receiving the thumb of an operator. According to the invention, the pressure surface (11) of the control button (12) is movable such as to be able, during operation, to assume multiple angles relative to the longitudinal axis (28) of the control rod (10).

Description

 ERGONOMIC CONTROL PICK-UP PIPETTE

DESCRIPTION The present invention relates to the field of sampling pipettes, also called laboratory pipettes or liquid transfer pipettes. They are intended for the collection and dispensing of liquid in containers or the like.

 The invention relates more specifically manual pipettes, single channel or multichannel. In known manner, the manual pipettes are intended to be held in the hand by an operator during the liquid collection and dispensing operations, these operations being performed by setting in motion a control knob obtained by the application of a axial pressure on the same button. The axial pressure applied to the control knob is transmitted to a piston of the pipette via a control rod of the pipette. The piston is displaced axially and causes a displacement of air leading to sampling and dispensing operations. This principle concerns so-called air displacement pipettes, in which a sampling cone is intended to be removably mounted on the tip of the pipette. Nevertheless, the invention also applies to so-called positive displacement pipettes intended to cooperate with capillary-piston consumables, the piston of which is intended to be directly in contact with the sample to be sampled, before being ejected. or reused. Positive-displacement pipettes therefore have a different design from that of more conventional air-displacement pipettes, in which the piston is an integral part of the pipette.

Whatever the design adopted, there is a constant need to improve the ergonomics of these pipettes, in particular to facilitate the movements of the thumb of the operator during dispensing and suctioning operations of the liquid, as well as during of the purge. Indeed, at the beginning of the descent stroke of the control rod, the inclined thumb of the operator has only a small contact surface with the button, which forces him to develop an important force to generate the desired displacement. This may result in problems with pipetting comfort, as well as the appearance of musculoskeletal disorders (MSDs).

 To meet this need, the subject of the invention is a set for a sampling pipette comprising a control rod at the end of which is arranged a control button intended to control the displacement of the control rod along a longitudinal axis of this, the button having a pressure surface for receiving the thumb of an operator. According to the invention, the pressure surface of the control button is movable so that, in operation, it can adopt several inclinations relative to the longitudinal axis of the control rod.

 In other words, it introduces an additional degree of freedom at the control button, so that in operation, the inclination of the pressure surface of the latter adapts to the changing inclination of the distal phalanx of the operator's thumb holding the pipette in hand. With this additional degree of freedom, the position of the pressure surface is thus able to evolve to follow the natural movement of rotation of the distal phalanx of the thumb, relative to the proximal phalanx, during the descent and the ascent of the control rod. This results in better pipetting comfort, including a better distribution of the constraints on the thumb joints, and a lower intensity effort to develop to cause the descent of the control rod via the button. This results in a reduction of muscular fatigue, as well as a limitation of the risks of appearance of musculoskeletal disorders.

 The invention has at least one of the following optional features, taken alone or in combination.

The control knob is pivotally mounted on the control rod, along a pivot axis arranged in a plane orthogonal to the longitudinal axis of the control rod. Alternatively, the control button could be made in two parts, including a base mounted on the control rod, and a movable end piece pivotally mounted on the base, and having said pressure surface to be contacted by the thumb. The control knob is pivotally mounted between two extreme positions, the passage from one to the other of the two extreme positions being effected by a pivoting of a total deflection angle of between 10 and 45 °, and more preferably included between 15 and 25 °.

 The assembly comprises means for returning the pressure surface in a rest position, which can indifferently be one or the other of the two extreme positions mentioned above.

 The pressure surface has a convex shape so as to define a cradle for receiving the thumb of the operator.

 The convexity axis of the pressure surface of the control knob is substantially orthogonal to a pivot axis of the control knob.

 The invention also relates to a sampling pipette comprising such an assembly, the pipette being of the air displacement or positive displacement type, and of the single-channel or multichannel type.

 Other advantages and features of the invention will become apparent in the detailed non-limiting description below.

 The description will be made with reference to the appended drawings among which;

FIG. 1 represents a perspective view of an air displacement sampling pipette, according to a preferred embodiment of the present invention;

 Figure 2 shows a more detailed side view of the pipette control knob shown in the previous figure;

 - Figure 3 shows a rear view of the control button shown in the previous figure;

 - Figure 4 shows a schematic view of the two extreme positions of the control button;

FIG. 5 represents the pipette held by the operator at the instant of a suction end of the liquid, at which point the button adopts one of the two extreme positions; and - Figure 6 shows the pipette held by the operator at the time of a stroke purge end of the liquid, at which point the button adopts the other of the two extreme positions.

 Referring first to Figure 1, there is shown a manually operated air displacement sampling pipette 1 according to a preferred embodiment of the present invention. Throughout the following description, the terms "high" and "low" are to be considered with the pipette held vertically, in the pipetting position or close to this same position.

 In Figure 1, there is shown the pipette 1 held by the hand 2 of an operator, who, with his thumb 4, actuates the pipette to generate the dispensing of a liquid that has been previously sucked.

 More specifically, the pipette 1 comprises a handle 6 forming the upper body of the pipette, the handle of which opens a pipetting control rod 10 carrying at its upper end, in the pipetting position, a control button 12 whose upper part is intended under pressure from the operator's thumb. More specifically, the button has a pressure surface 11 for receiving the thumb of the operator, this surface being generally oriented upwards.

 As a guide, it is noted that a display screen (not shown) can be provided on the handle 6. Similarly, the volume control means to be taken are also accessible to the operator on the handle 6.

 Under the handle 6, the pipette 1 comprises a removable lower part 14, which ends downwards by a cone holder 16 receiving a consumable 18, also called sampling cone. In known manner, after pipetting, the cone can be ejected mechanically by an ejector 20 whose actuating button 22 is for example projecting on the top of the handle, close to the control knob 12.

Figures 2 and 3 show in more detail the control knob 12, pivotally mounted at the upper end of the control rod 10. To ensure such pivoting, a pin 24 passes through both the rod 10 and the lower part of the button 12. The pin 24 is oriented according to a pivot axis 26, orthogonal to the axis longitudinally 28 of the control rod, and arranged in a plane orthogonal to the same axis 28. The latter also corresponds to the longitudinal axis of the pipette, and the direction of movement of the rod 10 during pipetting operations .

 It is noted that in a preferred embodiment of the invention, the part referenced 10 in FIGS. 2 and 3 does not constitute the upper end of the control rod, but alternatively constitutes a part of the knob 12. In fact, the control knob could be made in two parts, including a base mounted on the control rod and corresponding to the element referenced 10 in Figures 2 and 3, and a movable end piece pivotally mounted on the base, via the pawn 24.

 The button 12 thus has the pressure surface 11 of convex shape so as to define a cradle for receiving the thumb of the operator. This cradle takes a cylindrical shape, having two flanges 30 raised to prevent lateral sliding of the thumb. These two flanges 30 are arranged on either side of a convexity axis 11a of the surface 11, this axis 11a being orthogonal to the pivot axis 26.

 The radius of curvature R of the surface 11 is for example of the order of 20 mm. On the other hand, the spacing E between the pivot axis 26, and the bottom of the cradle defined by the surface 11, is of the order of 3 to 5 cm, and preferably about 4 cm. In addition, the distance D1 from a transverse plane PI of the knob 12 integrating the pivot axis 26, at a first end 36a of the same button 12, is between 10 and 14 cm, and preferably of the order 12 cm. Said first end 36a corresponds to an end along the axis of convexity 11a, and more specifically to that intended to cooperate with the front part of the distal phalanx of the thumb of the operator. Also, the distance D2 from the transverse plane PI to a second end 36b of the button 12 is between 13 and 17 cm, and preferably of the order of 15 cm. Said second end 36b is opposite the first along the convexity axis 11a, and therefore corresponds to that intended to cooperate with the posterior portion of the distal phalanx of the thumb.

The assembly 3 according to the invention, comprising the button 12 and the rod 10, is also equipped with means 40 for returning the button to a rest position, shown in FIGS. 2 and 3. It is preferable to a compression spring 40 interposed between a protrusion 42 of the button and the upper part of the control rod 10. In this regard, it is noted that in the embodiment mentioned above, in which the control knob is made in two parts with its base corresponding to the element referenced 10 in FIGS. 2 and 3, the spring 40 is then support on the same basis. The base advantageously provides a larger surface than that of the rod for receiving the spring 40. The base takes for example a tubular shape mounted around the upper end of the control rod, the pin 24 then passing through the base and the part upper button, as shown in Figure 1.

 The spring 40 thus recalls the button in a rest position which corresponds to a position in which it has a maximum inclination relative to a plane orthogonal to the longitudinal axis 28. This is one of the two extreme positions of a pivoting movement of the knob 12 along the axis 26.

 With this pivoting movement, the knob 12 can thus adopt several inclinations during the pipetting operations, by adapting to the evolutive position of the distal phalanx of the thumb of the operator.

In FIG. 4, the button 12 has been represented in the two extreme positions of its authorized pivoting movement about the axis 26. The most inclined position represented in dashed line, corresponding to that already shown in FIG. 2, is such that the angle Al between the horizontal 50 and the convexity axis 11a is of the order of 35 °. In this regard, it is noted that in FIG. 4, the straight line 50 embodies both the horizontal and a plane orthogonal to the axis 28. An angle Al greater than 35 ° is possible, but capable of generating parasitic forces This position is adopted when the rod is in high abutment, that is to say at the end of the sampling operation, and before the start of the dispensing operation. Indeed, in this configuration shown in Figure 5, the angle between the distal phalanx 4a and the proximal phalanx 4b is low. The distal phalanx 4a is thus strongly inclined relative to the horizontal, but the pivoting pressure surface 11 makes it possible to adapt perfectly to this particular orientation of the phalanx 4a, being itself inclined. In this position, the cradle of the knob thus receives the phalanx 4a whose longitudinal axis is advantageously parallel to the convexity axis 11a. This complementarity of shape is preserved during all pipetting operations, thanks to the pivoting nature of the button 12 which can follow the rotary movement of the distal phalanx 4a, relative to the proximal phalanx 4b.

 In FIG. 4, the button 12 has also been shown in the other of the two extreme positions of its pivoting movement about the axis 26. This is the least inclined position, approaching the fixed position encountered. on conventional pipettes. This second extreme position is that in which the angle A2 between the horizontal 50 and the convexity axis 11a is of the order of 15 °. A lower angle is possible, but less ergonomic because of the high inclination it requires between the distal and proximal phalanx 4a, 4b. This position is adopted when the rod is at the bottom stop, that is to say at the end of the dispensing operation or at the end of the purge operation. Indeed, in this configuration shown in Figure 6, the angle between the distal phalanx 4a and the proximal phalanx 4b is quite high. The distal phalanx 4a is therefore slightly inclined relative to the horizontal, but still perfectly received in the cradle of the button oriented accordingly.

 The total angle of deflection A3 of the button 12 is therefore of the order of 20 °, and more generally between 15 and 25 °. The transition from the first extreme position to the second extreme position is effected by counteracting the restoring force developed by the spring 40, which force is preferably very low so as not to affect the ergonomics of the pipette. Mechanical stop systems make it possible to limit the pivoting movement of the button 12 between the two extreme positions mentioned above. Moreover, it is noted that depending on the size of the thumb of the operator, the pipetting operations can be performed without reaching one and / or the other of the two extreme positions, but always observing an adaptation the inclination of the button 12 according to the evolution position of the distal phalanx 4a of the thumb of the operator.

 Of course, various modifications may be made by those skilled in the art to the invention which has just been described, solely by way of non-limiting examples.

Claims

An assembly (3) for a sampling pipette (1) comprising a control rod (10) at the end of which is arranged a control knob (12) for controlling the displacement of the control rod (10) according to a longitudinal axis (18) thereof, the button (12) having a pressing surface (11) for receiving the thumb (4) of an operator,  characterized in that the pressure surface (11) of the control knob (12) is movable so that, in operation, it can adopt several inclinations relative to the longitudinal axis (28) of the control rod (10). 2. An assembly according to claim 1, characterized in that the control knob (12) is pivotally mounted on the control rod (10), according to a pivot axis (26) arranged in a plane (50) orthogonal to the longitudinal axis (28) of the control rod (10). 3. The assembly of claim 2, characterized in that the control button (12) is pivotally mounted between two extreme positions, the passage from one to the other of the two extreme positions being effected by a pivoting of a total angle of deflection (A3) between 10 and 45 °, and more preferably between 15 and 25 °. 4. Assembly according to any one of the preceding claims, characterized in that it comprises means (40) for returning the pressure surface (11) in a rest position. 5. An assembly according to any one of the preceding claims, characterized in that the pressure surface (11) has a convex shape so as to define a cradle receiving the thumb of the operator. 6. An assembly according to claim 5, characterized in that the convexity axis (11a) of the pressure surface (11) of the control knob (12) is substantially orthogonal to a pivot axis (26) of the control knob. control (12). 7. sampling pipette (1) comprising an assembly (3) according to any one of the preceding claims. 8. Pipette according to the preceding claim, characterized in that it is air displacement or positive displacement. 9. Pipette according to claim 7 or claim 8, characterized in that it is monochannel or multichannel.