EP3749454B1 - System for ejecting tips of sampling pipettes with improved ergonomics - Google Patents

Description

TECHNICAL AREA

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

The invention relates to any type of pipette, mechanical, electronic or hydride, of the single-channel or multi-channel type.

The pipettes more preferably concerned by the present invention are mechanical pipettes with manual actuation. These pipettes are intended to be held in the hand by an operator during liquid sampling and dispensing operations. These operations are carried out by setting in motion a control button obtained by the application of an actuating pressure on this same button, via the operator's thumb. As mentioned above, the invention may also relate to hybrid pipettes, or even so-called electronic pipettes within which the movement of the piston is generated by a motor receiving an instruction from the operator, following a pressure exerted on a control button.

STATE OF THE PRIOR ART

One of the functions provided by the pipettes is the ejection of the sampling tips. This ejection is usually triggered by the operator who presses, with his thumb, on an ejection button located at the top of the pipette, near the control button.

The downward movement of the ejection button brings with it the entire ejection system, which, at its lower end, presses on the periphery of a cone fitted on the pipette tip, in order to cause its ejection. . This ejection requires exceeding the friction forces between the cone and its tip. From this In fact, the operator may have to exert a significant force on the ejection button to unmount the sampling cone.

Even if this solution is widely used in the pipettes known from the prior art, there remains a need for optimizing the ergonomics associated with the function of ejecting the sampling cones.

The documents WO 01/76752 , FR 3,040,896 and FR 2 980 123 describe known examples of pipettes comprising cone ejection systems.

DISCLOSURE OF THE INVENTION

• un bouton d'éjection de cône destiné à être déplacé en translation par le pouce d'un opérateur ;
• un dispositif d'éjection de cône ;
• des moyens élastiques de rappel permettant de rappeler le dispositif d'éjection de cône dans une position haute.
  Selon l'invention, le système comprend de plus un levier de commande du dispositif d'éjection, le levier de commande comportant :
• une première extrémité destinée à être montée sur une pièce de la pipette ;
• une seconde extrémité coopérant avec ledit bouton d'éjection, de façon à être sollicitée par celui-ci ;
• une portion intermédiaire d'actionnement du dispositif d'éjection de cône.

To at least partially meet the need identified above, the subject of the invention is a cone ejection system for a sampling pipette, the system comprising:

• a cone ejection button intended to be moved in translation by the thumb of an operator;
• a cone ejection device;
• elastic return means making it possible to return the cone ejection device to a high position.
  According to the invention, the system further comprises a control lever for the ejection device, the control lever comprising:
• a first end intended to be mounted on a part of the pipette;
• a second end cooperating with said ejection button, so as to be urged by the latter;
• an intermediate actuation portion of the cone ejection device.

The invention thus provides a simple, efficient and inexpensive response, improving the ergonomics of ejection of the sampling cones. Indeed, thanks to the particular use of the control lever, the ejection force to be exerted on the button is advantageously smaller than that required with the solutions of the prior art. Consequently, this specificity of multiplying the ejection force, via the control lever, provides ease of use for the operator.

In addition, the solution proposed by the invention has the advantage of retaining a linear movement of displacement of the control button, which contributes to the overall improvement of the ergonomics associated with the function of ejection of the cones. This type of linear movement also guarantees the solidity of the pipette, since the risk of breakage or damage to the ejection button is extremely low.

The invention also has at least any one of the following optional characteristics, taken individually or in combination.

• la première extrémité du levier de commande est montée articulée sur la pièce de la pipette ;
• le bouton d'éjection est en appui sur la seconde extrémité du levier de commande ;
• la portion intermédiaire d'actionnement du levier de commande est en appui sur le dispositif d'éjection de cône.

Preferably, the ejection system is designed as follows:

• the first end of the control lever is mounted articulated on the part of the pipette;
• the ejection button is pressed on the second end of the control lever;
• the intermediate actuation portion of the control lever bears on the cone ejection device.

In this preferred embodiment, the control lever is thus articulated at its first end, and resting on the ejection button as well as on the ejection device. Consequently, during an operation of ejecting a cone, the lever pivots while simple presses are observed at the level of its contacts with the button and the ejection device.

Another design could for example consist in providing a pivot connection between the second end of the control lever, and the ejection button. In such a case covered by the invention, the first end of the lever could then be mounted to slide and pivot, in a rail of the pipette part intended to cooperate with this lever. Similarly, the intermediate portion could be articulated on the cone ejection device, and the two ends of the lever simply resting on the pipette part and the ejection button.

Preferably, the connection between the intermediate actuation portion of the control lever, and the cone ejection device, is a point sphere-plane connection. This type of connection makes it possible to limit friction as much as possible during pivoting of the control lever. The wear of the parts concerned is thereby advantageously reduced. In addition, this type of connection makes it possible to transmit to the ejection device a force always oriented axially, offering great efficiency.

The ejection device has an upper portion biased by the elastic return means and intended to be housed in a fixed body forming a handle of the pipette, as well as a lower portion integral with the upper portion and defining an ejection end. cone.

The ejection device is intended to be movable in translation relative to the fixed body of the pipette.

The subject of the invention is also a sampling pipette comprising such a cone ejection system.

Preferably, the part on which the first end of the control lever is mounted is secured to the fixed body forming the handle of the pipette, or produced in one piece with this fixed body.

Preferably, the part on which the first end of the control lever is mounted is centered on a longitudinal central axis of the pipette, and traversed by a control rod of the pipette.

Preferably, a pivot axis of the first end of the control lever intercepts a longitudinal central axis of the pipette, preferably substantially orthogonally.

The pipette has an end-of-travel stop for the ejection button, said stop being secured to the fixed body forming the handle of the pipette, or made in one piece with this fixed body. This stop is preferably made of an elastomeric material.

Preferably, the ejection button projects upwards from the fixed body forming the handle of the pipette.

Preferably, the ejection button is movable in translation relative to the fixed body forming the handle of the pipette, preferably parallel to a longitudinal central axis of the pipette.

Finally, the pipette is preferably a mechanical pipette, but it could be an electronic or hybrid pipette with such a manual sampling cone ejection system.

Other advantages and characteristics of the invention will appear in the detailed non-limiting description below.

BRIEF DESCRIPTION OF THE DRAWINGS

• la figure 1 représente une vue de côté d'une pipette de prélèvement selon l'invention, avec son système d'éjection de cône dans un état inactif de repos ;
• la figure 2 est une vue similaire à la précédente, avec le système d'éjection de cône dans un état d'éjection ;
• la figure 3 représente une vue plus détaillée du système d'éjection de cône, avec son bouton dans une position inactive de repos ;
• la figure 4 est une vue similaire à la précédente, avec le bouton dans une position d'éjection du cône ; et
• la figure 5 est une vue partielle agrandie de celle de la figure 4, montrant plus particulièrement la butée de fin de course associée au bouton d'éjection.

This description will be made with reference to the accompanying drawings, among which;

• the figure 1 shows a side view of a sampling pipette according to the invention, with its cone ejection system in an inactive state of rest;
• the figure 2 is a view similar to the previous one, with the cone ejection system in an ejection state;
• the figure 3 shows a more detailed view of the cone ejection system, with its button in an inactive rest position;
• the figure 4 is a view similar to the previous one, with the button in a position of ejection of the cone; and
• the figure 5 is an enlarged partial view of that of the figure 4 , showing more particularly the end stop associated with the ejection button.

DETAILED PRESENTATION OF PREFERRED EMBODIMENTS

With reference to the figure 1 , there is shown a mechanical sampling pipette 1, comprising a cone ejection system 2 according to the invention. The pipette 1 has a manually actuated design, i.e. it is intended to be held by the hand of an operator, who, using his thumb 4, is able to actuate the pipette. pipette to generate the dispensation of a liquid which has previously been aspirated.

More precisely, the pipette 1 comprises in the upper part a fixed body forming a handle 6 of the pipette, from which handle opens a control rod 10. At the upper end of this rod 10, the pipette comprises a control button. pipetting control 12, the upper part of which is intended to undergo the pressure of the thumb 4 of the operator.

Under the handle 6, the pipette 1 comprises a removable lower part 14, which ends downwards with a cone-holder tip 16 receiving a consumable 18, also called a sampling cone. The cone ejection system 2 comprises an ejection device 24, of which a lower portion 20 projecting from the handle 6 defines a cone ejection end 22, surrounding the nozzle 16. This ejection end 22 is located opposite the upper end of the cone 18, so as to be able to cause it to be unhooked by pressing on its periphery.

The ejection device 24, of which only the lower portion 20 is visible on the figure 1 , is mounted to move in translation with respect to the handle 6 and to the lower part 14, both forming the fixed part 23 of the pipette. It is a translation in a direction parallel to a longitudinal central axis 8 of the pipette, according to which the control rod 10 is also movable in translation within the pipette. The control rod 10 is moreover centered on this axis 8.

The ejection system 2 also includes a cone ejection button 25, also controlled by the thumb 4 of the operator. The ejection button 25 is arranged projecting upwardly at the upper end of the handle 6, being offset laterally and axially from the control button 12. The ejection button 25 is mounted to move in translation with respect to the handle. handle 6, also parallel to the direction of the longitudinal central axis 8 of the pipette.

Thus, when the ejection button 25 is actuated downwards by the thumb of the operator as shown schematically on the figure 2 , this button causes the ejection device 24 to descend, in a manner specific to the invention which will be described below. The setting in motion of the lower portion 20 of the device 24 causes a translation of its ejection end 22 along the end piece 16, with the consequence of pressing the cone 18 which then quickly releases from this end piece. In this regard, it is noted that in the embodiment described and shown in the figures, it is a single-channel pipette carrying a single consumable 18. However, it could be a multichannel pipette carrying several cones, without departing from the scope of the invention.

Referring now to figures 3 and 4 , the ejection system 2 is shown in more detail. figure 3 represents the system in an idle state of rest, while the figure 4 represents this same system in a state of ejection of the cone, following an action by the operator on the ejection button 25.

In these figures, it is firstly noted that the ejection button 25 is movably mounted on a guide rail 42 of a fixed assembly 44, formed integrally with the handle 6, or secured to this handle by being fixedly mounted. on this one.

In addition to the lower portion 14, the ejection device 24 also comprises an upper portion 21 which is housed in the handle 6. The lower end of the upper portion has a plate 30 on which resilient return means, in the form of a compression spring 32. The other end of the spring bears on a fixed part 34 of the pipette arranged near the junction between the handle and the lower part 14, so as to return the entire device 24 to the upper position. Indeed, the lower and upper portions 20, 21 of the device 24 are integral with one another, and connected by a rod 36 visible on the figure 4 , which passes through the fixed part 34.

One of the particularities of the invention lies in the presence of a force multiplier element within the ejection system 2, namely a control lever 40. This lever 40 is interposed between the ejection button 25, and the upper portion 21 of the device 24 which it controls. It firstly comprises a first end 40a mounted articulated on a fixed part 46 of the aforementioned assembly 44. This fixed part 46 is centered on the longitudinal central axis 8, and takes the form of a sleeve traversed by the control rod 10. The pivot axis 48 of the first end 40a orthogonally intercepts the longitudinal central axis 8, and it is located offset downward with respect to the ejection button 25, when the latter occupies its inactive position of rest of the figure 3 .

The first end 40a can be formed from a single articulated branch, or else take the form of a yoke, the two ears of which are each articulated along the same axis 48 on the fixed part 46. In the latter case, the two ears yoke would be arranged on either side of the fixed part 46, received between these two ears.

The lever 40 has, opposite the first end 40a, a second end 40b on which the lower end of the ejection button 25 bears. It may be a connection of the sphere-plane or cylinder-plane type, in order to limit the sliding and the wear which results therefrom during the pivoting of the lever 40.

Finally, the lever 40 also comprises an intermediate actuating portion 40c, arranged between the two ends 40a, 40b, preferably while being substantially centered relative to the latter. This intermediate portion 40c is provided to actuate the upper portion 21 of the device 24 in translation, by resting on the upper end of this portion 21. To do this, a point sphere-plane connection 50 is provided between this intermediate portion 40c and the upper portion 21, for example by providing a truncated sphere 52 within the portion 40c of the control lever. In addition, this type of connection makes it possible to transmit to the upper portion 21 an ejection force always oriented axially, offering high efficiency.

Alternatively, still to limit the wear of the parts present, the truncated sphere can be made on the upper end of the upper portion 21 of the ejection device 24.

When system 2 is in its idle idle state of the figure 3 , the second end 40b is located higher than the first end 40a. As the button 25 is actuated downwards, the second end 40b on which it presses is moved downwards, and causes the rotation of the lever 40 about the pivot axis 48. During this rotation , during which the lever 40 passes through a median position in which it is oriented substantially orthogonally to the longitudinal central axis 8, the intermediate portion 40c presses on the upper portion 21 and drives the entire ejection device 24 downwards . This rotation of the lever 40 continues until the system 2 adopts its state of ejection from the figure 4 , wherein the second end 40b is lower than the first end 40a.

This ejection position is not marked by an end stop associated with the lever, but by an end stop of the ejection button 25, so as to limit the risk of damaging this lever 40. The stop here takes the form of one or more seals 60 made of elastomeric material, shown in the figure. figure 5 . These seals 60 are carried by the guide rail 42, at a top end thereof, in order to be contacted by a top end 62 of the button forming the pressure zone for the operator. Thus, at the end of the ejection operation, the operator pressing with his thumb on the pressure zone 62 is stopped in his movement by the stop of this same zone 62 on the seals made of elastomeric material 60.

The stroke of the ejection button 25 between its two extreme positions is for example of the order of 10 to 20 mm, while the incident stroke of the ejection device 24 is of the order of half that of the button 25 .

Of course, various modifications can be made by those skilled in the art to the invention which has just been described, solely by way of non-limiting examples, and the scope of which is defined by the appended claims.

Claims (14)

1. A cone ejection system (2) for a collection pipette, the system comprising:

   - a cone ejection knob (25) for being translationally moved by an operator's thumb (4);

   - a cone ejection device (24);

   - elastic return means (32) capable of returning the cone ejection device (24) into a high position,

   characterised in that it further comprises a control lever (40) for controlling the ejection device (24), the control lever including:

   - a first end (40a) for being mounted onto a piece (46) of the pipette;

   - a second end (40b) cooperating with said ejection knob (25), so as to be biased by the same;

   - an intermediate portion (40c) for actuating the ejection device (24).
2. The ejection system according to claim 1, characterised in that:

   - the first end (40a) of the control lever(40) is hingedly mounted onto the piece (46) of the pipette;

   - the ejection knob (25) is bearing on the second end (40b) of the control lever (40);

   - the intermediate portion (40c) for actuating the control lever (40) is bearing on the cone ejection device (24).
3. The ejection system according to claim 1 or claim 2, characterised in that the connection between the intermediate portion (40c) for actuating the control lever (40), and the cone ejection device (24), is a sphere-plane point connection (50).
4. The ejection system according to any of the preceding claims, characterised in that the ejection device (24) has a high portion (21) biased by the elastic return means (32) and for being housed in a fixed body forming a handle (6) of the pipette, as well as a low portion (20) integral with the high portion and defining a cone ejection end (22).
5. The ejection system according to the preceding claim, characterised in that the ejection device (24) is to be translationally movable with respect to the fixed body of the pipette.
6. A collection pipette (1) comprising a cone ejection system (2) according to any of the preceding claims.
7. The pipette according to claim 6, characterised in that the piece (46) onto which the first end (40a) of the control lever (40) is mounted is secured to the fixed body forming the handle (6) of the pipette, or made as a single piece with this fixed body.
8. The pipette according to claim 6 or claim 7, characterised in that the piece (46) onto which the first end (40a) of the control lever (40) is mounted is centred on a longitudinal central axis (8) of the pipette, and has a control rod (10) of the pipette therethrough.
9. The pipette according to any of claims 6 to 8, characterised in that a pivot axis (48) of the first end (40a) of the control lever (40) intersects a longitudinal central axis (8) of the pipette, preferably substantially orthogonally.
10. The pipette according to any of claims 6 to 9, characterised in that it has limit stop (60) for the ejection knob (25), said stop being secured to the fixed body forming the handle (6) of the pipette, or made as a single piece with this fixed body.
11. The pipette according to claim 10, characterised in that the stop (60) is made of an elastomeric material.
12. The pipette according to any of claims 6 to 11, characterised in that the ejection knob (25) projects upwardly from the fixed body forming the handle (6) of the pipette.
13. The pipette according to any of claims 6 to 12, characterised in that the ejection knob (25) is translationally movable with respect to the fixed body forming the handle (6) of the pipette, preferably in parallel to a longitudinal central axis (8) of the pipette.
14. The pipette according to any of claims 6 to 13, characterised in that it is a mechanical pipette.

Images