EP1268067B1 - Pipette provided with sampling volume adjusting means - Google Patents

Abstract

The sampling pipette includes means for adjusting the volume of liquid to be taken. It includes a locking element that is movable between an inactive position in which it makes the adjustment means unsuitable for performing adjustment and an active position in which it makes the adjustment means suitable for performing adjustment.

Description

The invention relates to sampling pipettes of liquid.

We know, for example from document FR-2,696,110, a sampling pipette comprising a dial accessible through a window of the body of the pipette to adjust the volume of liquid to be pipetted. This volume is also indicated on a display. This pipette has many advantages. The wheel does does not protrude out of the body of the pipette and is therefore unlikely to be activated unintentionally. In addition, the wheel is braked in its maneuver by a friction assembly that further reduces the risks of disturbance. However, it is desirable to perfect again. Indeed, he remains a weak risk of accidental disturbance of the volume to be pipetted by an involuntary maneuver of the wheel.

We therefore wish to eliminate any risk of accidental disturbance of the volume to be pipetted.

US-5,849,248 discloses a pipette comprising a movable locking element between a inactive position in which he makes the means of adjustment not suitable for setting and an active position in which he makes them fit. This element extends to near the volume control knob. No inadvertent adjustment of the volume to be pipetted is therefore not more to fear.

An object of the invention is to provide a pipette of a different type but also avoiding the maladjustment.

In order to achieve this goal, it is expected that according to the invention a sampling pipette comprising means for adjusting a volume of liquid to be sampled comprising at least one adjustment control member, the pipette comprising a movable locking element between an inactive position in which he makes the adjustment means not suitable for adjustment and a position active in which it makes the means of adjustment suitable for adjustment, the locking element being the setting control.

So, when the blocking element is in inactive position, no accidental volume to be pipetted is not possible. In addition, this elimination of the risks of disruption allows in return to remove or reduce the friction brake of the wheel, making it easier to maneuver voluntary adjustment. This deletion is all the more nice that it could happen with the pipette document FR-2 696 110 that the glove of the manipulator gets stuck between the wheel and the body of the pipette when actuating the knob. This inconvenience can be eliminated.

In addition, the pipette according to the invention allows use to perform by means of the single element of blocking all successive operations relating to setting, eg unlocking, volume control and lock.

• l'élément de blocage est mobile à coulissement entre les deux positions;
• l'élément de blocage est agencé pour être directement actionné de l'une à l'autre des deux positions par un utilisateur;
• l'élément de blocage s'étend à l'intérieur d'un corps de la pipette
• la pipette est agencée de sorte que l'élément de blocage est apte à transmettre un mouvement de réglage à un organe des moyens de réglage en position active, et est inapte à cette transmission en position inactive ;
• la pipette est agencée de sorte que l'élément de blocage est apte à transmettre un mouvement de l'un à l'autre de deux organes des moyens de réglage autres que l'élément de blocage en position active et est inapte à cette transmission en position inactive ;
• le mouvement est une rotation ;
• les moyens de réglage comprennent deux organes agencés pour être en crabotage mutuel lorsque l'élément de blocage est en position active et pour être désengagés l'un de l'autre lorsque l'élément de blocage est en position inactive ;
• la pipette comporte deux organes de commande de réglage;
• la pipette comporte un bouton de commande de prélèvement formant un organe de commande de réglage ;
• la pipette comporte des moyens de rappel de l'élément de blocage dans la position inactive;
• la pipette comporte des moyens pour maintenir l'élément de blocage dans la position active à l'encontre des moyens de rappel;
• la pipette est agencée de sorte que l'élément de blocage est apte à passer de la position active à la position inactive avec franchissement d'un point dur, et inversement, et
• les moyens de réglage comportent un organe moteur et un organe récepteur apte à être entraíné par l'organe moteur au moyen d'une liaison par complémentarité de forme, l'un des organes moteur et récepteur étant déformable de façon à interrompre la liaison lorsqu'il est soumis à une sollicitation d'intensité supérieure à une intensité prédéterminée.

The invention may furthermore have at least any of the following features:

• the locking element is slidably movable between the two positions;
• the locking element is arranged to be directly actuated from one to the other of the two positions by a user;
• the blocking element extends inside a body of the pipette
• the pipette is arranged so that the blocking element is able to transmit a control movement to a member of the adjustment means in the active position, and is unfit for this transmission in the inactive position;
• the pipette is arranged in such a way that the locking element is able to transmit a movement from one to the other of two members of the adjustment means other than the locking element in the active position and is unfit for this transmission by inactive position;
• the movement is a rotation;
• the adjustment means comprise two members arranged to be interconnected when the locking element is in the active position and to be disengaged from one another when the locking element is in the inactive position;
• the pipette comprises two adjustment control members;
• the pipette includes a sample control knob forming a regulating control member;
• the pipette comprises means for returning the blocking element in the inactive position;
• the pipette comprises means for holding the locking element in the active position against the return means;
• the pipette is arranged so that the blocking element is able to pass from the active position to the inactive position with crossing a hard point, and conversely, and
• the adjustment means comprise a motor member and a receiver member adapted to be driven by the motor member by means of a complementary fit connection, one of the motor and receiver members being deformable so as to interrupt the connection when it is subjected to a solicitation of intensity greater than a predetermined intensity.

• la figure 1 est une vue partielle en coupe axiale d'une pipette selon un mode préféré de réalisation de l'invention;
• la figure 2 est une vue en perspective d'une partie du mécanisme de réglage de la pipette de la figure 1 ;
• la figure 3 est une vue à plus grande échelle du mécanisme de la figure 2 ;
• la figure 4 est une vue en section axiale du mécanisme de la figure 2 ;
• la figure 5 est une vue en perspective d'une sous-partie du mécanisme de la figure 2 ;
• la figure 6 est une vue en élévation de la sous-partie de la figure 5;
• la figure 7 est une vue en perspective du crabot et de l'entraíneur du mécanisme de la figure 4 ;
• les figures 8 à 11 sont quatre vues partielles en coupe axiale montrant différentes étapes de la coopération du bouton de réglage et du coupleur du mécanisme de la figure 4 ;
• la figure 12 est une vue en coupe transversale de la sous-partie de la figure 6 suivant le plan XII-XII;
• la figure 13 est une vue en coupe éclatée de certains éléments de la figure 12 ;
• la figure 14 est une vue en coupe de la vis de réglage seule;
• les figures 15 à 18 illustrent différentes étapes de la coopération des éléments de la figure 12 ; et
• la figure 19 est une vue analogue à la figure 12 montrant une variante de réalisation de l'invention.

Other features and advantages of the invention will become apparent in the following description of a preferred embodiment and a variant given by way of non-limiting examples. In the accompanying drawings:

• Figure 1 is a partial axial sectional view of a pipette according to a preferred embodiment of the invention;
• Figure 2 is a perspective view of a portion of the pipette adjustment mechanism of Figure 1;
• Figure 3 is an enlarged view of the mechanism of Figure 2;
• Figure 4 is an axial sectional view of the mechanism of Figure 2;
• Figure 5 is a perspective view of a subpart of the mechanism of Figure 2;
• Figure 6 is an elevational view of the subpart of Figure 5;
• Figure 7 is a perspective view of the clutch and the driver of the mechanism of Figure 4;
• Figures 8 to 11 are four partial views in axial section showing different stages of the cooperation of the adjusting knob and the coupler of the mechanism of Figure 4;
• Figure 12 is a cross-sectional view of the subpart of Figure 6 along the plane XII-XII;
• Figure 13 is an exploded sectional view of some elements of Figure 12;
• Figure 14 is a sectional view of the adjusting screw alone;
• Figures 15 to 18 illustrate different steps of the cooperation of the elements of Figure 12; and
• Figure 19 is a view similar to Figure 12 showing an alternative embodiment of the invention.

The sampling pipette according to this mode of embodiment of the invention is of the same type as of document FR-2 696 110. It will therefore be referred to document for some details of the pipette already known from this document. We will describe here in detail only certain aspects of the volume adjustment mechanism.

The pipette 2 conventionally comprises a body 2 as a handle to be grasped by the hand of the user. The pipette comprises a piston illustrated mobile sliding axis longitudinal 10 of the pipette into a cavity bottom of the pipette to suck in it a volume of liquid to be withdrawn or expelled out of this cavity. The movement of the piston is controlled in particular by means of a control rod 4 of axis 10 connected in the lower part to the piston by parts of a known type and not illustrated. This rod 4 is surmounted at its upper end by a button pusher 6 rigidly attached to the rod, that the user can operate with the thumb of the hand holding the pipette. Thus the piston lowers and goes up in function of the same movement of the button. The pipette has a return spring adapted to replace the piston and the upper stem at the end of their run towards the bottom for the expulsion of the liquid, and a spring of purge adding its effect to that of the previous spring when the piston stroke continues down for a purge race.

The volume to be pipetted during a normal race complete piston, out of purge stroke, can be adjusted by means of an adjustment knob 8 in the form of ring and push button 6. These two buttons are rotatably mounted about the longitudinal axis 10 of the pipette. A rotation of one or other of these buttons causes the rotation of a coaxial adjusting screw 5 to the rod 4 about its axis 10. The way the rotation of the screw 5 causes the variation of the volume to pipeter is known and will not be described. We go now describe in detail the upper part of adjustment mechanism.

All the pieces that will now be described have axis 10 for axis of symmetry except otherwise stated.

With reference to FIGS. 1 to 4, the pipette comprises a coupler 12 slidably mounted on the rod 4 but fixed in rotation relative thereto. AT this end, the coupler has a top orifice central having three engaging radial tabs 14 in three longitudinal grooves 16 of the rod 4. This orifice is formed by an upper washer 18 of coupler. The coupler has three arms 20 extending downwards parallel to axis 10 from the washer 18. Each arm 20 is generally flattened in the radial direction at axis 10 and present on its face 22 opposite the axis an elongated relief 24 next the circumferential direction to the axis 10.

The adjustment knob 8 is movable to slide along the axis 10 and rotated about this axis. he has a substantially cylindrical shape of axis 10. The outer face 26 of this button is accessible to the user for his maneuvering through windows from the body. To this end, it includes reliefs of gripping. Near its upper circular edge, the button 8 has three forks 30 extending in radial projection in the direction of the axis. These forks have a female "U" shape open in direction of the axis, complementary shape to the profile arms 20 and receiving them respectively.

It follows from this arrangement that button 8 is fixed in rotation to the coupler 12 but is not fixed in sliding. Button 8 can occupy on the one hand a low position, or inactive position, or position locked, and on the other hand a high position or active or unlocked. These two positions are independent of the angular position of the knob 8 around the axis. The button goes from one to another position by sliding along the axis. The coupler 12 has an annular spring 26 of axis 10 requesting radially the arms 20 on their inner face for tend to move them away radially from the axis.

In the low position, as shown in Figures 1-4 and 8, the arms 20 are received in the forks but not the reliefs 24. It is the same in the high position, as shown in Figure 11. During the movement of transition from one to the other, as illustrated in Figures 8 to 11, the reliefs 24 pass in the forks and cause temporary bending of the arms 20 in the radial direction. This passage produces a click sound and constitutes a hard point during the maneuver who demonstrate to the user the change of high or low position. In addition, the reliefs 24 hold the button in the up position against of the return spring, unless the action of the the user.

With reference to FIGS. 1, 4 and 7, the pipette has a clutch 32 of generally cylindrical shape having an outer annular peripheral rib 34 about halfway up. Button 8 has two cylindrical parts 8a and 8b lower and upper force-fitted externally on dog clutch 32 and in axial support on the rib 34. The button 8 is rigidly attached to the dog. The dog present on his outer face, illustrated in detail in FIG. reliefs cooperating with complementary reliefs of the button to ensure these rigid links. The dog 32 has a toothing 36 extending near its edge superior, projecting radially from its internal face in direction of the axis.

The pipette comprises a coach 38 having an upper portion 40 of cylindrical shape provided with several teeth 42, for example two in number, extending near its upper edge, protruding radial from its outer face in the opposite direction to axis. These two teeth are able to engage with the teeth 36 of the clutch when they extend to the same height as this along the axis 10.

The coach 38 can be made mobile relative to the adjusting screw 5. It extends directly opposite of it radially. Unlike the screw of setting 5 which is moving according to a movement helical around the axis 10, the coach 38 is fixed sliding along the axis 10 relative to the body of the pipette. It is blocked for this purpose in part superior by a spacer 44 and partly lower by a piece 46 illustrated in Figure 1.

With particular reference to FIGS. 5, 6 and 12, the coach 38 has two main legs 48 and two secondary legs 50 extending parallel to the axis 10 down from the top 40. The secondary legs 50 are sector-shaped of cylinder axis 10. They are alternated around the axis with the main legs 48. The legs main 48 have a cylindrical outer face and have a planar inner surface projecting radially from which extends a rib 52 profiled parallel to the axis 10 and rectangular section. The coach 38 has a spring 54 encircling externally the four legs 48, 50 and housed in an external notch of these. The spring tends to bring the legs closer radially from the axis.

The adjusting screw 5 is hollow and traversed longitudinally by the control rod 4. These two parts are totally independent in their relative motion. The adjusting screw 5 has a shape circular general of revolution. However, more precisely, it presents two parallel flats 56 to each other and to axis 10 and opposite of share and else of this axis. These flats extend over a medial portion 58 of the screw extending over a threaded lower portion 60 of the screw serving volume adjustment. These flats 56 are joined one to the other by arcs 61. The adjusting screw has two longitudinal pins 62 parallel to the axis 10, extending at the edge of the flats respective ones so as to present a stop when circumferentially travels the outer face of the screw 5 from the flats, but also so as to have an arc of a circle that does not form an abutment from cylindrical areas 61.

The two lugs 62 are not symmetrical one of the other relative to axis 10 but are relative to at a median plane of the screw parallel to the two flats. In addition, the two lugs 62 do not extend exactly coincidentally with respect to their position along the axis 10. They overlap on a certain section. But one of the spurs extends higher than the other while the latter is stretching down more than the first. Also, are the two spurs partial overlap along the axis 10. The longitudinal position of the second lug, normally hidden in Figure 6, has however been indicated by the line 56.

The coach 38 can be coupled to the screw 5 in rotation, or uncoupled from it.

When coupled, as in Figures 12 and 15, the coach is located at a level of the screw on which overlap the two pins 62. The legs secondary 48 are supported on the cylindrical areas 61 whose form they follow. They realize with these a surface-to-surface contact. The ribs 52 are supported radially on the flats 56 and abutting on the respective lugs 62. Spring 54 keeps the four tabs resting on the screw 5 and especially keeps taking the ribs on the pins. Therefore, a rotational movement of the coach 38 can be transmitted to the adjusting screw 5. As the coach is slidably fixed along of the axis unlike the screw 5, this rotation produces the sliding of the screw along the axis, the screw having a helical movement. The two pieces are thus coupled to rotation about the axis by means of friction forces and especially by means of the lugs and ribs. Transmission of the couple therefore takes place even in presence of a strong resistant torque.

The lugs 62 are positioned so that neighborhood of each end position high and bottom of the adjusting screw 5, the pin that ensures the transmission of movement towards this stop interrupts, as illustrated in FIGS. 14 to 18. Therefore, over the entire range of motion remaining at to travel to the stop position, the transmission of the couple is done only thanks to friction forces of the legs on the screw. In these conditions, this transmission takes place only if the intensity of the binding forces, and therefore the intensity of the resistant torque, is less than a value predetermined function of the spring 54. This transmission nevertheless takes place, so that the user can continue to maneuver (indirectly as we will see later) coach 38 for drive the screw 5. As soon as the screw 5 arrives at the end of adjustment stroke, the resistant torque becomes infinitely big and interrupts the link by the friction forces. Despite the recall effect of the spring 54, the main legs 48 then deviate for leave the flats and get to areas 61 for follow the shape of the screw and the coach 38 turns only. The adjusting screw 5 is practically no longer solicited and remains motionless. The thread 60 of the screw 5 is therefore protected from solicitations excessive.

If the user wants to operate the screw 5 in the other direction from that position, he simply to operate the coach 38 in the other direction. Before less than half a turn, one of the 52 ribs encounters the other lug 62 and the two pieces are again related to rotation in the other direction. The same operation takes place in the vicinity of the other end of the adjustment stroke.

We will now describe the operation of the adjustment button 8.

The low, inactive, locked position of button is illustrated in Figures 1, 3 and 4. The arms 20 are engaged with the button 8. The rod 4 is therefore in rotation with the button 8. In this position, the teeth 36 of the clutch are out of reach with the 42 teeth of the coach 38. No movement of the button 8 therefore does not rotate the coach 38 or the screw 5. This low position of the 8 button therefore inactivates adjustment means. The volume to be pipetted can not be modified voluntarily or involuntarily. The the words "locked" or "locked" written on the outer face 26 of the button 8 appear in the window to the user. A spring of recall 60 illustrated in Figure 1 taking support axially upwards on the coupler 12 and towards the down button 8 solicits the latter for the keep in this low position.

If the user wants to adjust the volume, he or she slide the button 8 upwards against the spring 60 so the forks 30 crossing the reliefs 24 produce a click and a hard point. The button is then in the upper position, active, unlocked. He is kept in this position by the reliefs 24, unless the user otherwise acts. In this position, the teeth 36 of the clutch are in taken with the 42 teeth of the coach 38. A direct request button 8 or button 6 to rotation exerted by the user is therefore transmitted by the teeth 36, 42 to the coach 38, then to the screw of setting 5 in so far as it is not already at the end of the stroke for the desired direction of adjustment. When the desired sample volume is set, the user makes the button 8 slide again in low position to prevent misalignment untimely.

We notice, in the pipette that has just been described, that the tightening of the coach 38 on the screw 5 and therefore their clutch or clutch are done automatically and not by the direct action of the user on these parts. In addition, the user never directly actuates the adjusting screw 5.

It can be expected that two elements 5, 38, the one that is deformable to interrupt their liaison is the screw 5.

FIG. 19 illustrates a variant of realization in which analogous elements have numerical references increased by 100. The stem 104 has not been illustrated.

In this variant, the ribs 152 have a "V" profile with rounded tip. Flats 156 are replaced by grooves 156 with a "V" profile of same angle as that of the ribs to allow the drive of the screw 105 by the coach 138. At the vicinity of the stop positions, the grooves the respective ones widen by accentuating the inclination from one of their two faces. This face forms a ramp. The pipette is arranged so that when the end position is reached, the strength of tightening of the spring is insufficient to maintain the ribs 152 in the grooves 156. The ramp causes then the output of the ribs out of the grooves and the distance of the main legs 148, so that the coach no longer drives the screw and continues to turn alone.

The pipette may include means electronic displays (eg crystal of a parameter relating to the operation of the pipette. For example, these means may indicate permanently locked or unlocked state of button 8.

Claims (13)

1. Sampling pipette comprising means (6, 12, 8, 38, 5) for adjusting a volume of liquid to be sampled, comprising at least one adjustment control member, the pipette comprising a blocking element (8) able to move between an inactive position in which it renders the adjusting means unable to adjust and an active position in which it renders the adjusting means able to adjust, the blocking element being the adjustment control member, characterized in that the pipette is arranged in such a way that the or each adjustment control member can move while remaining in the inactive position.
2. Pipette according to Claim 1, characterized in that the blocking element (8) can move in sliding between the two positions.
3. Pipette according to Claim 1 or 2, characterized in that the blocking element (8) extends inside a body of the pipette.
4. Pipette according to any one of Claims 1 to 3, characterized in that it is arranged in such a way that the blocking element (8) is able to transmit an adjusting movement to a member (38) of the adjusting means in the active position, and is unable to transmit in this way in the inactive position.
5. Pipette according to any one of Claims 1 to 4, characterized in that it is arranged in such a way that the blocking element (8) is able to transmit a movement from one (12) to the other (38) of two members of the adjusting means other than the blocking element in the active position, and is unable to transmit in this way in the inactive position.
6. Pipette according to either one of Claims 4 and 5, characterized in that the movement is a rotation.
7. Pipette according to any one of claims 1 to 6, characterized in that the adjusting means comprise two members (8, 38) arranged to mesh together when the blocking element (8) is in an active position and to be disengaged from one another when the blocking element is in an inactive position.
8. Pipette according to any one of claims 1 to 7, characterized in that the pipette has two adjustment control members (6, 8).
9. Pipette according to any one of claims 1 to 8, characterized in that it comprises a sampling control knob (6) forming an adjustment control member.
10. Pipette according to any one of claims 1 to 9, characterized in that it comprises return means (60) for returning the blocking element (8) to the inactive position.
11. Pipette according to Claim 10, characterized in that it comprises means (24) for holding the blocking element (8) in the active position against the action of the return means (60).
12. Pipette according to any one of Claims 1 to 11, characterized in that it is arranged in such a way that the blocking element is able to move from the active position to the inactive position passing through a hard point.
13. Pipette according to any one of Claims 1 to 12, characterized in that the adjusting means comprise a drive member (38) and a receiving member (5) able to be driven by the drive member at least by means of a connection through complementing shapes, one (38) of the drive and receiving members being deformable in such a way as to break the connection when subjected to stress of an intensity greater than a predetermined intensity.

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