EP0776247B1 - Pipette for distributing successive volumes of a liquid - Google Patents

Pipette for distributing successive volumes of a liquid Download PDF

Info

Publication number
EP0776247B1
EP0776247B1 EP95927786A EP95927786A EP0776247B1 EP 0776247 B1 EP0776247 B1 EP 0776247B1 EP 95927786 A EP95927786 A EP 95927786A EP 95927786 A EP95927786 A EP 95927786A EP 0776247 B1 EP0776247 B1 EP 0776247B1
Authority
EP
European Patent Office
Prior art keywords
lever
housing
pipette
piston rod
syringe
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP95927786A
Other languages
German (de)
French (fr)
Other versions
EP0776247A1 (en
Inventor
Eric Marteau D'autry
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of EP0776247A1 publication Critical patent/EP0776247A1/en
Application granted granted Critical
Publication of EP0776247B1 publication Critical patent/EP0776247B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
    • B01L3/02—Burettes; Pipettes
    • B01L3/021—Pipettes, i.e. with only one conduit for withdrawing and redistributing liquids
    • B01L3/0217—Pipettes, i.e. with only one conduit for withdrawing and redistributing liquids of the plunger pump type
    • B01L3/0234—Repeating pipettes, i.e. for dispensing multiple doses from a single charge

Definitions

  • the present invention relates to a pipette for dispensing successive volumes of liquid by repeated action on a pusher.
  • the pusher is arranged to exert a pressing force in the vicinity of the free end of the second part of the lever, and cause, by jamming effect, the rod thrust.
  • the lever is also resiliently urged upwards, so that it automatically returns to its rest position against the stop higher when the pusher is released.
  • the object of the present invention is to propose a new pipette with increased accuracy compared to known pipettes, even after prolonged use.
  • the lever rotatably mounted around of a geometric axis perpendicularly cutting the axis of said bore substantially halfway through the latter, is arranged on the push rod between a lower sleeve and an upper sleeve mounted at sliding on the push rod, and the lever has two surfaces of revolutions centered on said geometric pivot axis, arranged with on either side of the lever hole through which the push rod passes and at contact of the lower and upper sleeves.
  • the lower sleeve comes, when the lever reaches its end position, in abutment against said fixed stop.
  • said surfaces of revolution are formed by balls crimped in holes in the lever.
  • said pusher comprises a sheath sliding mounted inside the housing, and inside which can freely slide the push rod. It is provided at one end with a contact part having a sharp edge intended to press the lever to train it in tilting around said geometric axis then in displacement in the longitudinal direction of the push rod.
  • the adjustment mechanism comprises a screw of adjustment to turn to adjust the travel movement of the lever and the volume distributed with each action on the pusher.
  • This adjusting screw is internally traversed by the sheath and the push rod and meshes with a volume indicating mechanism.
  • the adjusting screw has an end edge defining said variable stop, and the sleeve upper has a clean end edge to come into contact punctual with it.
  • the operating button equipping the pusher comprises a first part mounted to slide on a second part, with the interposition of a first return spring.
  • a second return spring with a lower stiffness constant than the first resides elastically between the housing and said second part to resiliently recall the pusher away from said orifice passage of the liquid.
  • the stiffness constant of said return means elastic bands urging the lever towards its rest position is less than the stiffness constant of the first and second return springs.
  • the syringe and the plunger rod are fixed removably to the pipette case via a clamp in the form of a part, the upper part of which is integral with the lower end of the push rod, the part of which median has a recess suitable for receiving the upper end free from the piston rod, and the lower part of which has elastic arms allowing the introduction and maintenance of the upper piston, and the lower end of the housing comprises means suitable for detachably attach the syringe body while allowing free sliding of the pliers and the piston rod.
  • the middle part of the clamp comprises a recess bounded by the free upper faces of the clamps, by a shoulder surface, by a transverse surface and by a surface longitudinal.
  • the pipette according to the invention shown in Figure 1 comprises a housing 1 made of plastic, of oblong shape, suitable for gripping by a user.
  • a syringe 2 is mounted so removable at the lower longitudinal end of the housing 1 for the collection and distribution of successive volumes of liquid.
  • This syringe 2 has a generally cylindrical body 3 of revolution around an X axis, extended below by a frustoconical tip 4 open at its top in 4 'for the passage of the liquid.
  • a piston rod 5 made of plastic is slidably mounted in the body 3, the seal being provided by an annular lip 6 located at lower part of the piston rod 5.
  • the latter has, below the lip 6, a conical lower end 7, shaped to engage in the tapered end 4 in order to expel the liquid as best as possible therein when the piston rod 5 reaches the end of the downward stroke.
  • the body 3 has at its upper end 8 a protruding rim outwards and retained by blistering in an annular groove 9 of the case 1, or by any other equivalent arrangement which allows mounting and easy disassembly of the syringe and plunger assembly on the end open bottom of case 1.
  • FIGS. 1a, 11, 12 and 13 A particularly advantageous embodiment of a fastener allowing assembly and disassembly, which are rapid and simultaneous times of the syringe 2 and piston rod 5 assembly, will described later in more detail with reference to FIGS. 1a, 11, 12 and 13.
  • the annular groove 9 is formed on the surface radially internal of a generally cylindrical housing 10 of revolution around of the X axis, formed in the lower part of the housing 1, and in which can reassemble the piston rod 5 of the syringe 2 when a sample of liquid is carried out.
  • the wall 11 of the housing 1 delimiting this housing 10 is generally cylindrical of revolution around the X axis, and it is open over part of its length, parallel to the X axis, to form a longitudinal slot 12 intended for the passage of a finger 13 of the piston rod 5, as will be specified in the after.
  • the piston rod 5 has at its upper end a coupling part 14 detachably connected to the end lower of a push rod 15 mounted with longitudinal sliding along the X axis in the housing 1.
  • the push rod 15 is cylindrical of revolution around the X axis for its upper part slidably mounted in the housing 1 and widens at its lower end to form a housing 16 cylindrical of revolution around the X axis, intended to receive the part coupling 14 of the piston rod 5.
  • This coupling part 14 is corrugated, presenting a succession of three friction discs 17, of same diameter, regularly spaced along a smaller core 18 diameter than the discs 17. The retention of the coupling part 14 to the interior of the housing 16 is effected by friction.
  • Finger drive 13 is fixed to the wall 19 of the push rod 15 delimiting the housing 16, and extends through the slot 12.
  • the drive finger 13a has been raised to the upper part of the housing 1 to facilitate access to the drive finger 13a for a user handling the pipette only in one hand.
  • this assumes of course that the finger 13 a extends internally to the housing by a sort of strip 13 b securing it with a control piece and fixing the piston tail.
  • the lower part of this strip 13 b ending in a brightly colored tongue which becomes visible from the outside of the housing, at the end of the pipette stroke, that is to say when the body of the syringe 2 is on the point of emptying entirely.
  • the housing 1 houses in the upper part a mechanism 20 of adjustment of the volume to be distributed which will be described in more detail below, as well as an indicator assembly 21 of this volume, coupled to the mechanism 20 adjustment.
  • the sheath 40 descends and drives, via of a unidirectional transmission 24, the push rod 15 and the piston 5 downwards, i.e. in the direction of the orifice 4 'for passage of the liquid, to dispense liquid, while the movement back to the top of the sleeve 40 is carried out alone under the action of return means elastic formed by a helical spring 25, independently of the push rod 15 and piston rod 5 which each retain their position in the housing 1 and the body 3 of the syringe 2, under the effect of the friction exerted by the lip 6 on the body 3 of the syringe 2.
  • the elastic return means are produced in the form of a helical spring 25 a which no longer works in compression like the spring 25, but in tension.
  • the one-way transmission 24 which is now described more particularly with reference to FIG. 2 comprises a lever 26 generally extending transversely to the axis X, having a central circular bore 27 for passage with a small clearance of the push rod 15.
  • This small clearance allows an angular movement of the lever 26 between a rest position where the axis of the central bore 27 is substantially parallel to the X axis (which allows free movement of the lever 26 on the push rod 15) and a downward oblique position relative to the X axis (for driving the push rod 15 by jamming effect).
  • the drive lever 26 is disposed on the push rod 15 between an upper sleeve 28 and a lower sleeve 29, both sliding mounted on the latter.
  • a coil spring 30 working in compression is placed between the lower sleeve 29 and a ring 31 serving as a fixed stop, axially retained against a shoulder internal 32 of the housing 1.
  • the ring 31 closes by its lower face the housing 10, and has on the opposite side thereof a central part 33 cylindrical of revolution around the X axis, bored for the passage of the push rod 15 and a wall 34, cylindrical of revolution around the X axis, forming an annular groove 35 with the central part 33 open up.
  • the wall 34 is in contact by its radially surface external with box 1.
  • the helical spring 30 comes to bear axially, at its lower end 36, in the bottom of the annular groove 35, and at its upper end 37 against a shoulder 38 of the lower sleeve 29.
  • the sheath 40 of the pusher 22 is cylindrical in revolution around the X axis, and the metal push rod 15, can slide freely at inside of it.
  • the sheath 40 is extended at its lower end by a contact piece 41 intended to come to press the lever 26 to train it in tilting then, after jamming of the push rod 15, moving along the axis X at the same time as the push rod 15.
  • the contact piece 41 has a first part 44 which is connected to a end on the sleeve 40, extending radially outwards perpendicular to the X axis over a distance greater than the radius outer of the sheath 40, for connecting to a second part 46 extending obliquely downward away from the X axis, forming an angle of about 45 ° with it.
  • Part Two 46 presents its lower end a sharp edge 47 intended to exert pressure in the vicinity of the radially outermost free end 48 (in the cutting plane of FIGS. 1 and 2) of the lever 26.
  • the upper sleeve 28 is generally cylindrical of revolution around the X axis; he is bored from its upper end edge 39 over more than half of its length to receive the lower end of the sleeve 40.
  • the wall 42 of the upper sleeve 28 delimiting the bore intended to receive the sheath 40 is open on its periphery to form a slot longitudinal 43 intended for the passage of the contact piece 41.
  • the assembly constituted by the lever 26 and the sleeves lower 29 and upper 28 moves inside a guide piece 49 generally tubular around the X axis, open downwards and closed at its upper part, except for a thread 63 centered on the X axis for the passage of a hollow adjustment screw 62, inside which can slide the sheath 40 and the push rod 15.
  • the guide piece 49 has a shouldered lower end 50, engaging in the groove annular 35 of the ring 31, in contact with the radially internal surface of the wall 34, until the shoulder stops against the upper edge of the wall 34.
  • the guide piece 49 comes to bear, by its end edge upper 51, against the volume indicator assembly 21.
  • the lever 26 is shown with the push rod 15 in perspective in FIG. 3. It is mainly constituted by a plate extending perpendicular to the axis of the central hole 27, having a first part 53 crossed in its center by the hole central 27 for the passage with a small clearance of the push rod 15 and a second part 54 laterally extending the first part 53 to serve as support for the contact piece 41.
  • the first part 53 is crossed by two holes 55 and 56 located on either side of the central bore 27, each serving as a housing for a ball 57 or 58 retained by crimping in the wafer.
  • the plane P 2 containing the axes of the central bore 27 and those of the holes 55 and 56 receiving the balls 57 and 58 extends perpendicularly to a median plane P 1 for the lever 26, containing the axis of the central bore 27 and the direction in which the second part 54 of the lever 26 extends.
  • the second part 54 has, in section in a plane parallel to the plane P 2, a rectangular section.
  • the balls 57 and 58 are interposed axially between the sleeve lower 29 and the upper sleeve 28, and constitute means of guide to guide the tilting of the lever 26 when the workpiece contact 41 extending below the sheath 40 presses the end 48 of the second part 54.
  • This tilting takes place around a geometric axis of rotation Y intersecting the X axis perpendicularly, appreciably mid-thickness of the central bore 27.
  • a play more or less pronounced, caused by wear, for the passage of the push rod 15 in the central bore 27 of the lever 26 is translated in accordance with the invention by a more or less large tilting of the lever 26 around of the geometric axis of rotation Y, until the rod of the thrust 15 against the edges of the central bore 27.
  • the geometric axis of Y rotation of lever 26 remains fixed during the tilting operation of this latest.
  • the upper sleeve 28 has, on its edge upper end 39, an upwardly convex boss 60, the vertex defines a point contact with the lower end edge 61 of the adjusting screw 62.
  • the latter is internally traversed by the sleeve 40 as indicated previously and it is threaded externally to engage, at the bottom, with the thread 63 of the guide piece 49.
  • the assembly constituted by the screw adjustment 62 and the guide piece 49 constitutes the aforementioned mechanism 20 of adjustment of the volume to be distributed, allowing the stroke to be varied lowering of the lever 26, therefore that of the push rod 15 and of the rod piston 5, at each action on the pusher 22, as will be specified in the following.
  • the adjusting screw 62 has at its upper end a flange 64 accessible from outside the housing 1 by the user, at through unrepresented openings made in the housing 1.
  • the flange 64 is advantageously knurled on its radially surface external to facilitate manual rotation of the screw setting 62 by the user.
  • a brake can also be added to the adjustment screw 62, to exert a friction force with the housing 1 and prevent inadvertent adjustment of the volume during use selected by the user.
  • the collar 64 of the adjusting screw 62 turns inside a part 65 generally cylindrical of revolution around the X axis, provided with openings intended to coincide with those of the box 1 for access from the outside to the flange 64.
  • a washer of closure 66 is attached to the upper end edge of the Exhibit 65. The latter is drilled in its lower part to receive a nut 67 through which the adjusting screw 62 passes.
  • the indicator assembly 21 is known in itself and will not be not described in detail. It is, in the example shown, of the type comprising three volume indicator drums to be distributed, juxtaposed and meshing with each other and with the adjusting screw 62, in a manner known per se. The volume to be dispensed is indicated to the user by the drums at the through a transparent window 68.
  • FIG. 5 shows the sheath 40 of the pusher 22 after a first race, called a comfort race, a distance B from the rest position of the sleeve 40 until the edge 47 contacts lever 26.
  • the sheath 40 drives, through the contact piece 41, the lever 26 downwards, and the movement of the latter is accompanied by the movement of the push rod 15, due to the jamming of this last in the central hole 27.
  • the downward movement of the lever 26 is transmitted to the lower sleeve 29 by the balls 57 and 58, and the latter moves down against the coil spring 30, until it stops of the lower end edge 70 of the lower sleeve 29 against the upper end edge 71, flat and generally perpendicular to the X axis, from the central part 33 of the ring 31.
  • the rod thrust 15 has descended by a distance A corresponding to the distance initial between the lower end edge 70 of the lower sleeve 29 and the upper end edge 71 of the central part 33 of the ring 31.
  • the push rod 15 drives down its piston rod 5 and a predetermined volume of liquid is expelled through the orifice 4 '.
  • the lever 26 rises alone, independently of the push rod 15, due to the absence of jamming of the latter in the hole 27 when the contact piece 41 does not exert pressure on the end 48.
  • the lever 26 is returned by the coil spring 30 to its rest position corresponding to the abutment of the upper sleeve 28 against the lower end edge 61 of the adjusting screw 62.
  • the user By acting on the adjustment screw 62, the user can change the initial gap between the lower end edge 70 of the lower sleeve 29 and upper end edge 71 of the part central 33 of the ring 31, therefore the distance A and the volume which will be dispensed during the next pressure on the operating button 23.
  • the operating button 23 has two parts telescopically assembled one on top of the other. More specifically, the operating button 23 has a lower portion 81 bored at 82 to come and fit on the upper end edge of the sleeve 40, until it stops in the bottom of bore 82. This the latter is bordered on the outside, downwards, by a cylindrical wall 83 forming with the sheath 40 an annular groove 84 open downwards to receive the upper end of the spring 25. The latter works in compression and elastically interposed between the bottom of the groove 84 and the closing washer 66, crossed in its center by the sheath 40.
  • the operating button 23 also includes an upper part 80, which is slidably mounted along the X axis on the lower part 81.
  • the latter is provided at its upper end with tabs of retainer 86 each having, on the radially outer side, a tooth protruding, suitable for abutting against a shoulder 87 formed on the radially internal surface of the upper part 80, to retain axially the latter.
  • a helical spring 88 working in compression is mounted inside the top 80 for to intervene elastically between the upper front face 89 of the lower part 81 and the bottom 90 of the upper part 80, and apply elastically the latter up until the teeth of the tabs 86 against the shoulder 87.
  • the user presses on the upper part 80 of the operating button 23.
  • the pushing force is transmitted by through the spring 88 at the lower part 81, therefore at the sheath 40, and the latter moves down to the stop of the lower sleeve 29 against the ring 31.
  • the return spring 25 of the sleeve 40 in its position rest is then compressed. If the user continues to press the operating button 23, the upper part 80 covers the part lower 81 as shown in FIG. 10. In fact, the user does not feels that spring 88 is compressed only after the sleeve lower 29 has reached the ring 31.
  • the user drives the operating button 23 a sufficient distance so that the push rod 15 is driven over the entire stroke A down.
  • the lower sleeve 29 remains in abutment for the time of relaxation of the spring 88. This limits jolts on the push rod 15 and ensures the complete delivery of the volume of liquid to be dispensed.
  • the stiffness constant of spring 88 is greater than that of springs 25 and 30.
  • the stiffness constant of spring 25 is greater than that of spring 30.
  • the invention makes it possible to obtain a precision perfectly constant pipette despite wear of the central bore 27 and the push rod 15. It is not limited to the example of realization described. One can in particular modify the attachment of the syringe 2 on the housing 1 and the connecting means between the piston rod 5 and the rod thrust 15.
  • FIG. 11 represents, in perspective, a mode of particularly advantageous embodiment of the fixing means of the syringe 3 and piston rod 5 assembly at the lower end of the housing 1 of the pipette.
  • the clamp 100 is constituted by a mass piece put in place at the lower end of the pipette case 1 in the position illustrated by the sections of Figures 1a and Figures 12 and 13. It includes an open part provided with two elastic branches 101 opening towards the exterior to facilitate guidance and allow the introduction of the end of the piston rod 5.
  • the inner faces of the two branches elastic 101 are connected together by a cylindrical surface 102 in which the tail of the piston rod 5 will stop.
  • these elastic branches 101 are located at the lower part of the clamp 100 which in its part center has a recess intended to allow mounting and disassembly of the piston tail.
  • This recess is delimited by three generally flat surfaces which are essential for ensuring the mounting and retaining the piston tail previously described more in details.
  • a surface shoulder 103 which is constituted by a small flat surface extending in the longitudinal axis of the pipette and serving as a surface hooking and supporting the upper friction disc 17 of the tail the piston rod 5.
  • the attachment function of the shoulder surface 103 is illustrated by the position of the plunger syringe assembly in FIG. 12.
  • the clamp 100 has a transverse surface 104 which is not strictly perpendicular to the X axis of the pipette but has a slight inclination of a few degrees thus creating a clearance allowing the pivoting of the upper disc 17 of the piston rod 5. It is therefore not strictly speaking of a stop or support surface.
  • the middle position of the clamp 100 has a longitudinal surface 105 transverse support of the tail of the piston rod.
  • the pipette further comprises a metal clamp 106 of suitable elasticity blocking the lower part of the pipette in its correct working position, as illustrated in figure 13.
  • This clamp 106 has essential function of keeping syringe 2 pressed on the lower retaining flange 107 of the pipette case, while the rod piston 5 can move with the clamp 100 inside the housing 10 of the pipette.
  • the upper part 108 of the clamp 100 includes means of attachment to the upper end of the push rod 15 for controlling the longitudinal movements of the clamp assembly 100 and piston 5 in said housing 10 of the pipette.

Landscapes

  • Health & Medical Sciences (AREA)
  • Clinical Laboratory Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Devices For Use In Laboratory Experiments (AREA)
  • Infusion, Injection, And Reservoir Apparatuses (AREA)

Description

La présente invention concerne une pipette pour distribuer des volumes successifs de liquide par action répétée sur un poussoir.The present invention relates to a pipette for dispensing successive volumes of liquid by repeated action on a pusher.

On a décrit dans la demande de brevet français n° 2 432 161 une pipette comprenant un boítier de forme oblongue, incorporant un mécanisme de réglage du volume à distribuer, et une seringue à fixer de façon amovible à l'extrémité inférieure dudit boítier. Un piston apte à se déplacer de façon étanche à l'intérieur du corps de la seringue est monté à l'extrémité inférieure d'une tige de poussée pouvant coulisser longitudinalement au travers du boítier. L'entraínement de la tige de poussée vers le bas, par action sur un poussoir, pour distribuer un volume prédéterminé de liquide, s'effectue par l'intermédiaire d'un levier d'entraínement pouvant se déplacer selon une course prédéterminée entre une butée inférieure fixe et une butée supérieure réglable. Ce levier comprend une première partie traversée par un perçage permettant le passage avec un faible jeu de la tige de poussée et une seconde partie s'étendant transversalement à l'axe dudit perçage. Le poussoir est agencé pour exercer une force de pression au voisinage de l'extrémité libre de la seconde partie du levier, et entraíner, par effet de coincement, la tige de poussée. Le levier est par ailleurs élastiquement sollicité vers le haut, de sorte qu'il regagne automatiquement sa position de repos contre la butée supérieure lorsque le poussoir est relâché. Ce type de pipette a donné satisfaction. Toutefois, l'usure des différentes pièces constitutives de la pipette se traduit à la longue par une précision moindre.We have described in French patent application No. 2,432,161 a pipette comprising an oblong case, incorporating a volume adjustment mechanism to distribute, and a syringe to attach removably at the lower end of said housing. A piston capable of move tightly inside the syringe body is mounted to the lower end of a sliding push rod longitudinally through the housing. The rod training pushed down, by action on a pusher, to distribute a volume predetermined liquid, is effected by means of a lever which can move according to a predetermined course between a fixed lower stop and an adjustable upper stop. This lever includes a first part crossed by a hole allowing the passage with little play of the push rod and a second part extending transversely to the axis of said bore. The pusher is arranged to exert a pressing force in the vicinity of the free end of the second part of the lever, and cause, by jamming effect, the rod thrust. The lever is also resiliently urged upwards, so that it automatically returns to its rest position against the stop higher when the pusher is released. This type of pipette gave satisfaction. However, the wear of the various constituent parts of the pipette results in lower accuracy over time.

La présente invention a pour objet de proposer une nouvelle pipette présentant une précision accrue par rapport aux pipettes connues, même après une utilisation prolongée.The object of the present invention is to propose a new pipette with increased accuracy compared to known pipettes, even after prolonged use.

Cette pipette est du type comprenant :

  • un boítier de forme oblongue, incorporant un mécanisme de réglage du volume de liquide à distribuer,
  • une seringue à monter de façon amovible à une extrémité du boítier, comprenant un corps de seringue muni d'un orifice de passage du liquide et une tige de piston montée à déplacement dans ledit corps de seringue,
  • une tige de poussée montée à coulissement longitudinal dans le boítier, à relier à une extrémité, de façon amovible, à ladite tige de piston,
  • un levier d'entraínement pour entraíner seulement en direction dudit orifice de passage du liquide la tige de poussée et la tige de piston, le levier s'étendant transversalement l'axe longitudinal de la tige de poussée et étant muni d'un perçage pour le passage de celle-ci avec un faible jeu, le levier étant en outre monté avec une possibilité de déplacement dans le boítier, sur une course réglable dans la direction longitudinale de la tige de poussée, entre une position de repos définie par une butée réglable du mécanisme de réglage et une position de fin de course définie par une butée fixe, et étant rappelé vers la position de repos par des moyens de rappel élastiques,
  • ledit poussoir étant monté à coulissement longitudinal dans le boítier, étant muni à une extrémité s'étendant hors du boítier d'un bouton de manoeuvre et pouvant agir par l'autre extrémité sur le levier pour l'orienter en oblique sur la tige de poussée, puis entraíner celle-ci par coincement en direction de l'orifice de passage du liquide avec la tige de piston pour expulser un volume prédéterminé de liquide, défini par la course du levier entre lesdites positions de repos et de fin de course, le mouvement de retour du levier vers sa position de repos après chaque action sur le poussoir s'effectuant sous l'action desdits moyens de rappel élastiques alors que la tige de piston conserve sa position dans le corps de la seringue.
This pipette is of the type comprising:
  • an oblong box, incorporating a mechanism for adjusting the volume of liquid to be dispensed,
  • a syringe to be removably mounted at one end of the housing, comprising a syringe body provided with a liquid passage orifice and a piston rod mounted to move in said syringe body,
  • a push rod mounted for longitudinal sliding in the housing, to be connected at one end, in a removable manner, to said piston rod,
  • a driving lever for driving only in the direction of said liquid passage orifice the push rod and the piston rod, the lever extending transversely the longitudinal axis of the push rod and being provided with a hole for the passage thereof with little play, the lever being further mounted with a possibility of movement in the housing, on an adjustable stroke in the longitudinal direction of the push rod, between a rest position defined by an adjustable stop of the adjustment mechanism and an end position defined by a fixed stop, and being returned to the rest position by elastic return means,
  • said pusher being mounted in longitudinal sliding in the housing, being provided at one end extending outside the housing with an operating button and being able to act by the other end on the lever to orient it obliquely on the push rod , then drive it by wedging in the direction of the liquid passage orifice with the piston rod to expel a predetermined volume of liquid, defined by the stroke of the lever between said rest and end positions, the movement return of the lever to its rest position after each action on the plunger being effected by the action of said elastic return means while the piston rod retains its position in the body of the syringe.

De façon caractéristique, le levier, monté à rotation autour d'un axe géométrique coupant perpendiculairement l'axe dudit perçage sensiblement à mi-épaisseur de ce dernier, est disposé sur la tige de poussée entre un manchon inférieur et un manchon supérieur montés à coulissement sur la tige de poussée, et le levier présente deux surfaces de révolution centrées sur ledit axe géométrique de pivotement, disposées de part et d'autre du perçage du levier traversé par la tige de poussée et au contact des manchons inférieur et supérieur. Le manchon inférieur vient, lorsque le levier atteint sa position de fin de course, en butée contre ladite butée fixe. Typically, the lever, rotatably mounted around of a geometric axis perpendicularly cutting the axis of said bore substantially halfway through the latter, is arranged on the push rod between a lower sleeve and an upper sleeve mounted at sliding on the push rod, and the lever has two surfaces of revolutions centered on said geometric pivot axis, arranged with on either side of the lever hole through which the push rod passes and at contact of the lower and upper sleeves. The lower sleeve comes, when the lever reaches its end position, in abutment against said fixed stop.

On obtient ainsi, quelle que soit l'augmentation, par usure, du jeu de passage de la tige dans le perçage du levier, un basculement de ce dernier autour d'un même axe géométrique de rotation jusqu'au coincement de la tige de poussée dans le perçage ; si l'usure est prononcée, le levier bascule davantage mais cela reste sans conséquence sur la course de la tige de poussée, à la différence des pipettes connues. Dans ces dernières, le levier n'était pas guidé lors de son mouvement de basculement et celui-ci pouvait s'accompagner d'un léger glissement sur la tige de poussée, avec pour résultat que cette dernière n'était pas entraínée sur la totalité de la distance définie par l'écart entre les butées fixe et réglable, de sorte que la précision de la pipette s'en trouvait affectée.Whatever the increase, by wear, is thus obtained rod clearance in the hole in the lever, this tilting last around the same geometric axis of rotation up to jamming of the push rod in the hole; if wear is pronounced, the lever tilts more but this has no effect on the stroke of the push rod, unlike known pipettes. In these last, the lever was not guided during its movement of tilting and this could be accompanied by a slight sliding on the push rod, with the result that it was not driven over the entire distance defined by the distance between the stops fixed and adjustable, so the accuracy of the pipette was there affected.

Avantageusement, lesdites surfaces de révolution sont formées par des billes serties dans des perçages du levier.Advantageously, said surfaces of revolution are formed by balls crimped in holes in the lever.

Avantageusement, ledit poussoir comporte un fourreau monté à coulissement à l'intérieur du boítier, et à l'intérieur duquel peut librement coulisser la tige de poussée. Il est muni à une extrémité d'une pièce de contact présentant une arête vive destinée à appuyer sur le levier pour l'entraíner en basculement autour dudit axe géométrique puis en déplacement selon la direction longitudinale de la tige de poussée.Advantageously, said pusher comprises a sheath sliding mounted inside the housing, and inside which can freely slide the push rod. It is provided at one end with a contact part having a sharp edge intended to press the lever to train it in tilting around said geometric axis then in displacement in the longitudinal direction of the push rod.

Avantageusement, le mécanisme de réglage comporte une vis de réglage à tourner pour régler la course en déplacement du levier et le volume distribué à chaque action sur le poussoir. Cette vis de réglage est traversée intérieurement par le fourreau et la tige de poussée et engrène avec un mécanisme indicateur du volume. La vis de réglage présente une tranche d'extrémité définissant ladite butée variable, et le manchon supérieur présente une tranche d'extrémité propre à venir en contact ponctuel avec celle-ci.Advantageously, the adjustment mechanism comprises a screw of adjustment to turn to adjust the travel movement of the lever and the volume distributed with each action on the pusher. This adjusting screw is internally traversed by the sheath and the push rod and meshes with a volume indicating mechanism. The adjusting screw has an end edge defining said variable stop, and the sleeve upper has a clean end edge to come into contact punctual with it.

Avantageusement, le bouton de manoeuvre équipant le poussoir comporte une première partie montée à coulissement sur une deuxième partie, avec interposition d'un premier ressort de rappel. Un deuxième ressort de rappel de constante de raideur inférieure au premier s'interpose élastiquement entre le boítier et ladite deuxième partie pour rappeler élastiquement le poussoir en éloignement dudit orifice de passage du liquide. La constante de raideur desdits moyens de rappel élastiques sollicitant le levier vers sa position de repos est inférieure à la constante de raideur des premier et deuxième ressorts de rappel.Advantageously, the operating button equipping the pusher comprises a first part mounted to slide on a second part, with the interposition of a first return spring. A second return spring with a lower stiffness constant than the first resides elastically between the housing and said second part to resiliently recall the pusher away from said orifice passage of the liquid. The stiffness constant of said return means elastic bands urging the lever towards its rest position is less than the stiffness constant of the first and second return springs.

Avantageusement, la seringue et la tige de piston sont fixées de façon amovible au boítier de la pipette par l'intermédiaire d'une pince se présentant sous la forme d'une pièce dont la partie supérieure est solidaire de l'extrémité inférieure de la tige de poussée, dont la partie médiane comporte un évidement propre à recevoir l'extrémité supérieure libre de la tige de piston, et dont la partie inférieure comporte des branches élastiques permettant l'introduction et le maintien de la tige de piston, et l'extrémité inférieure du boítier comprend des moyens aptes à fixer de façon amovible le corps de la seringue tout en autorisant le libre coulissement de la pince et de la tige de piston.Advantageously, the syringe and the plunger rod are fixed removably to the pipette case via a clamp in the form of a part, the upper part of which is integral with the lower end of the push rod, the part of which median has a recess suitable for receiving the upper end free from the piston rod, and the lower part of which has elastic arms allowing the introduction and maintenance of the upper piston, and the lower end of the housing comprises means suitable for detachably attach the syringe body while allowing free sliding of the pliers and the piston rod.

Avantageusement, la partie médiane de la pince comporte un évidement délimité par les faces supérieures libres des pinces, par une surface d'épaulement, par une surface transversale et par une surface longitudinale.Advantageously, the middle part of the clamp comprises a recess bounded by the free upper faces of the clamps, by a shoulder surface, by a transverse surface and by a surface longitudinal.

D'autres caractéristiques et avantages de la présente invention apparaítront à la lecture de la description détaillée qui va suivre, d'un exemple de réalisation non limitatif de l'invention, et à l'examen du dessin annexé sur lequel :

  • les figures 1 et la sont des vues en coupe longitudinale de deux modes de réalisation différents d'une pipette conforme à l'invention,
  • la figure 2 est une coupe longitudinale partielle, à échelle agrandie, de la pipette représentée sur la figure 1,
  • la figure 3 représente, en perspective, le levier d'entraínement traversé par la tige de poussée,
  • les figures 4 à 7 représentent des positions successives du levier d'entraínement au cours de l'utilisation de la pipette,
  • les figures 8 à 10 représentent des positions successives du bouton de manoeuvre équipant le poussoir de la pipette au cours de l'utilisation de celle-ci,
  • la figure 11 est une vue en perspective d'une pince de fixation de la queue de piston, et
  • les figures 12 et 13 illustrent la mise en place par pivotement de l'ensemble seringue piston.
Other characteristics and advantages of the present invention will appear on reading the detailed description which follows, of a non-limiting exemplary embodiment of the invention, and on examining the appended drawing in which:
  • FIGS. 1 and la are views in longitudinal section of two different embodiments of a pipette according to the invention,
  • FIG. 2 is a partial longitudinal section, on an enlarged scale, of the pipette shown in FIG. 1,
  • FIG. 3 represents, in perspective, the drive lever crossed by the push rod,
  • FIGS. 4 to 7 represent successive positions of the drive lever during the use of the pipette,
  • FIGS. 8 to 10 represent successive positions of the operating button equipping the pusher of the pipette during the use of the latter,
  • FIG. 11 is a perspective view of a pliers for fixing the piston tail, and
  • Figures 12 and 13 illustrate the implementation by pivoting of the plunger syringe assembly.

Dans la description qui va suivre, les termes "inférieur" et "supérieur" seront utilisés pour décrire la pipette alors que celle-ci est dans une position généralement verticale d'utilisation.In the following description, the terms "lower" and "superior" will be used to describe the pipette while it is in a generally vertical position of use.

La pipette conforme à l'invention représentée sur la figure 1 comporte un boítier 1 en matière plastique, de forme oblongue, adaptée à la préhension par un utilisateur. Une seringue 2 est montée de façon amovible à l'extrémité longitudinale inférieure du boítier 1 pour le prélèvement et la distribution de volumes successifs de liquide. Cette seringue 2 présente un corps 3 généralement cylindrique de révolution autour d'un axe X, prolongé inférieurement par un embout tronconique 4 ouvert à son sommet en 4' pour le passage du liquide. Une tige de piston 5 en matière plastique est montée à coulissement de façon étanche dans le corps 3, l'étanchéité étant assurée par une lèvre annulaire 6 située en partie inférieure de la tige de piston 5. Cette dernière présente, en deçà de la lèvre 6, une extrémité inférieure 7 conique, conformée pour s'engager dans l'embout tronconique 4 afin d'expulser au mieux le liquide contenu dans celui-ci lorsque la tige de piston 5 arrive en fin de course vers le bas. Le corps 3 présente à son extrémité supérieure 8 un rebord formant saillie vers l'extérieur et retenu par cloquage dans une gorge annulaire 9 du boítier 1, ou par tout autre agencement équivalent qui permet un montage et un démontage aisés de l'ensemble seringue et piston sur l'extrémité inférieure ouverte du boítier 1.The pipette according to the invention shown in Figure 1 comprises a housing 1 made of plastic, of oblong shape, suitable for gripping by a user. A syringe 2 is mounted so removable at the lower longitudinal end of the housing 1 for the collection and distribution of successive volumes of liquid. This syringe 2 has a generally cylindrical body 3 of revolution around an X axis, extended below by a frustoconical tip 4 open at its top in 4 'for the passage of the liquid. A piston rod 5 made of plastic is slidably mounted in the body 3, the seal being provided by an annular lip 6 located at lower part of the piston rod 5. The latter has, below the lip 6, a conical lower end 7, shaped to engage in the tapered end 4 in order to expel the liquid as best as possible therein when the piston rod 5 reaches the end of the downward stroke. The body 3 has at its upper end 8 a protruding rim outwards and retained by blistering in an annular groove 9 of the case 1, or by any other equivalent arrangement which allows mounting and easy disassembly of the syringe and plunger assembly on the end open bottom of case 1.

Un mode de réalisation particulièrement avantageux d'une pièce de fixation permettant un montage et un démontage, qui soient à la fois rapides et simultanés de l'ensemble seringue 2 et tige de piston 5, sera décrit ultérieurement plus en détail en regard des figures 1a, 11, 12 et 13.A particularly advantageous embodiment of a fastener allowing assembly and disassembly, which are rapid and simultaneous times of the syringe 2 and piston rod 5 assembly, will described later in more detail with reference to FIGS. 1a, 11, 12 and 13.

La gorge annulaire 9 est ménagée sur la surface radialement interne d'un logement 10 généralement cylindrique de révolution autour de l'axe X, formé en partie inférieure du boítier 1, et dans lequel peut remonter la tige de piston 5 de la seringue 2 lorsqu'un prélèvement de liquide est effectué. La paroi 11 du boítier 1 délimitant ce logement 10 est généralement cylindrique de révolution autour de l'axe X, et elle est ouverte sur une partie de sa longueur, parallèlement à l'axe X, pour former une fente longitudinale 12 destinée au passage d'un doigt d'entraínement 13 de la tige de piston 5, comme cela sera précisé dans la suite.The annular groove 9 is formed on the surface radially internal of a generally cylindrical housing 10 of revolution around of the X axis, formed in the lower part of the housing 1, and in which can reassemble the piston rod 5 of the syringe 2 when a sample of liquid is carried out. The wall 11 of the housing 1 delimiting this housing 10 is generally cylindrical of revolution around the X axis, and it is open over part of its length, parallel to the X axis, to form a longitudinal slot 12 intended for the passage of a finger 13 of the piston rod 5, as will be specified in the after.

La tige de piston 5 présente à son extrémité supérieure une partie d'accouplement 14 reliée, de façon amovible, à l'extrémité inférieure d'une tige de poussée 15 montée à coulissement longitudinal selon l'axe X dans le boítier 1.The piston rod 5 has at its upper end a coupling part 14 detachably connected to the end lower of a push rod 15 mounted with longitudinal sliding along the X axis in the housing 1.

La tige de poussée 15 est cylindrique de révolution autour de l'axe X pour sa partie supérieure montée à coulissement dans le boítier 1 et s'élargit à son extrémité inférieure pour former un logement 16 cylindrique de révolution autour de l'axe X, destiné à recevoir la partie d'accouplement 14 de la tige de piston 5. Cette partie d'accouplement 14 est annelée, présentant une succession de trois disques de friction 17, de même diamètre, régulièrement espacés le long d'une âme 18 de moindre diamètre que les disques 17. La retenue de la partie d'accouplement 14 à l'intérieur du logement 16 s'effectue par frottement. Le doigt d'entraínement 13 est fixé sur la paroi 19 de la tige de poussée 15 délimitant le logement 16, et s'étend au travers de la fente 12.The push rod 15 is cylindrical of revolution around the X axis for its upper part slidably mounted in the housing 1 and widens at its lower end to form a housing 16 cylindrical of revolution around the X axis, intended to receive the part coupling 14 of the piston rod 5. This coupling part 14 is corrugated, presenting a succession of three friction discs 17, of same diameter, regularly spaced along a smaller core 18 diameter than the discs 17. The retention of the coupling part 14 to the interior of the housing 16 is effected by friction. Finger drive 13 is fixed to the wall 19 of the push rod 15 delimiting the housing 16, and extends through the slot 12.

Dans le mode de réalisation représenté à la figure 1a, le doigt d'entraínement 13a a été remonté vers la partie supérieure du boítier 1 pour faciliter l'accès du doigt d'entraínement 13a pour un utilisateur ne manipulant la pipette que d'une seule main. Comme cela apparaít sur la figure 1a, cela suppose bien sûr que le doigt 13a se prolonge intérieurement au boítier par une sorte de réglette 13b le solidarisant d'avec une pièce de commande et de fixation de la queue du piston. La partie inférieure de cette réglette 13b se terminant par une languette de couleur vive qui devient visible de l'extérieur du boítier, en bout de course de la pipette, c'est-à-dire lorsque le corps de la seringue 2 est sur le point de se vider entièrement.In the embodiment shown in Figure 1a, the drive finger 13a has been raised to the upper part of the housing 1 to facilitate access to the drive finger 13a for a user handling the pipette only in one hand. As shown in Figure 1a, this assumes of course that the finger 13 a extends internally to the housing by a sort of strip 13 b securing it with a control piece and fixing the piston tail. The lower part of this strip 13 b ending in a brightly colored tongue which becomes visible from the outside of the housing, at the end of the pipette stroke, that is to say when the body of the syringe 2 is on the point of emptying entirely.

Le boítier 1 loge en partie supérieure un mécanisme 20 de réglage du volume à distribuer qui sera décrit plus en détail dans la suite, ainsi qu'un ensemble indicateur 21 de ce volume, couplé au mécanisme 20 de réglage. Un poussoir 22, comprenant un fourreau métallique 40 équipé à sa partie supérieure d'un bouton de manoeuvre 23, est monté à coulissement dans le boítier 1 selon l'axe X pour permettre à l'utilisateur de distribuer des volumes successifs de liquide par pressions répétées vers le bas sur le bouton de manoeuvre 23.The housing 1 houses in the upper part a mechanism 20 of adjustment of the volume to be distributed which will be described in more detail below, as well as an indicator assembly 21 of this volume, coupled to the mechanism 20 adjustment. A pusher 22, comprising a metal sheath 40 fitted at its upper part of an operating button 23, is mounted at sliding in the housing 1 along the X axis to allow the user to distribute successive volumes of liquid by repeated pressure towards the bottom on the operating button 23.

A chaque pression exercée par l'utilisateur sur le bouton de manoeuvre 23, le fourreau 40 descend et entraíne, par l'intermédiaire d'une transmission unidirectionnelle 24, la tige de poussée 15 et la tige de piston 5 vers le bas, c'est-à-dire en direction de l'orifice 4' de passage du liquide, pour distribuer du liquide, alors que le mouvement de retour vers le haut du fourreau 40 s'effectue seul sous l'action de moyens de rappel élastiques constitués par un ressort hélicoïdal 25, indépendamment de la tige de poussée 15 et de la tige de piston 5 qui conservent chacune leur position dans le boítier 1 et le corps 3 de la seringue 2, sous l'effet de la friction exercée par la lèvre 6 sur le corps 3 de la seringue 2. Each time the user presses the maneuver 23, the sheath 40 descends and drives, via of a unidirectional transmission 24, the push rod 15 and the piston 5 downwards, i.e. in the direction of the orifice 4 'for passage of the liquid, to dispense liquid, while the movement back to the top of the sleeve 40 is carried out alone under the action of return means elastic formed by a helical spring 25, independently of the push rod 15 and piston rod 5 which each retain their position in the housing 1 and the body 3 of the syringe 2, under the effect of the friction exerted by the lip 6 on the body 3 of the syringe 2.

Dans le mode de réalisation de la figure 1a, les moyens de rappel élastiques sont réalisés sous la forme d'un ressort hélicoïdal 25a qui ne travaille plus en compression comme le ressort 25, mais en traction.In the embodiment of FIG. 1a, the elastic return means are produced in the form of a helical spring 25 a which no longer works in compression like the spring 25, but in tension.

La transmission unidirectionnelle 24 qui est maintenant décrite plus particulièrement en référence à la figure 2 comporte un levier 26 s'étendant généralement transversalement à l'axe X, présentant un perçage circulaire central 27 pour le passage avec un faible jeu de la tige de poussée 15. Ce faible jeu autorise un débattement angulaire du levier 26 entre une position de repos où l'axe du perçage central 27 est sensiblement parallèle à l'axe X (ce qui permet un libre déplacement du levier 26 sur la tige de poussée 15) et une position en oblique vers le bas par rapport à l'axe X (pour l'entrainement de la tige de poussée 15 par effet de coincement).The one-way transmission 24 which is now described more particularly with reference to FIG. 2 comprises a lever 26 generally extending transversely to the axis X, having a central circular bore 27 for passage with a small clearance of the push rod 15. This small clearance allows an angular movement of the lever 26 between a rest position where the axis of the central bore 27 is substantially parallel to the X axis (which allows free movement of the lever 26 on the push rod 15) and a downward oblique position relative to the X axis (for driving the push rod 15 by jamming effect).

Le levier d'entraínement 26 est disposé sur la tige de poussée 15 entre un manchon supérieur 28 et un manchon inférieur 29, tous deux montés à coulissement sur cette dernière. Un ressort hélicoïdal 30 travaillant en compression est placé entre le manchon inférieur 29 et une bague 31 servant de butée fixe, retenue axialement contre un épaulement interne 32 du boítier 1. La bague 31 ferme par sa face inférieure le logement 10, et présente du côté opposé à ce dernier une partie centrale 33 cylindrique de révolution autour de l'axe X, alésée pour le passage de la tige de poussée 15 et une paroi 34, cylindrique de révolution autour de l'axe X, ménageant avec la partie centrale 33 une gorge annulaire 35 ouverte vers le haut. La paroi 34 est au contact par sa surface radialement externe avec le boítier 1.The drive lever 26 is disposed on the push rod 15 between an upper sleeve 28 and a lower sleeve 29, both sliding mounted on the latter. A coil spring 30 working in compression is placed between the lower sleeve 29 and a ring 31 serving as a fixed stop, axially retained against a shoulder internal 32 of the housing 1. The ring 31 closes by its lower face the housing 10, and has on the opposite side thereof a central part 33 cylindrical of revolution around the X axis, bored for the passage of the push rod 15 and a wall 34, cylindrical of revolution around the X axis, forming an annular groove 35 with the central part 33 open up. The wall 34 is in contact by its radially surface external with box 1.

Le ressort hélicoïdal 30 vient axialement en appui, à son extrémité inférieure 36, dans le fond de la gorge annulaire 35, et à son extrémité supérieure 37 contre un épaulement 38 du manchon inférieur 29. Le fourreau 40 du poussoir 22 est cylindrique de révolution autour de l'axe X, et la tige de poussée 15, métallique, peut coulisser librement à l'intérieur de celui-ci.The helical spring 30 comes to bear axially, at its lower end 36, in the bottom of the annular groove 35, and at its upper end 37 against a shoulder 38 of the lower sleeve 29. The sheath 40 of the pusher 22 is cylindrical in revolution around the X axis, and the metal push rod 15, can slide freely at inside of it.

Le fourreau 40 est prolongé, à son extrémité inférieure, par une pièce de contact 41 destinée à venir appuyer sur le levier 26 pour l'entraíner en basculement puis, après coincement de la tige de poussée 15, en déplacement selon l'axe X en même temps que la tige de poussée 15. La pièce de contact 41 présente une première partie 44 se raccordant à une extrémité sur le fourreau 40, s'étendant radialement vers l'extérieur perpendiculaire-ment à l'axe X sur une distance supérieure au rayon externe du fourreau 40, pour se raccorder à une deuxième partie 46 s'étendant obliquement vers le bas en éloignement de l'axe X, en formant un angle de 45° environ avec celui-ci. La deuxième partie 46 présente à son extrémité inférieure une arête vive 47 destinée à exercer une pression au voisinage de l'extrémité libre 48 radialement la plus externe (dans le plan de coupe des figures 1 et 2) du levier 26. Le manchon supérieur 28 est généralement cylindrique de révolution autour de l'axe X ; il est alésé depuis sa tranche d'extrémité supérieure 39 sur plus de la moitié de sa longueur pour recevoir l'extrémité inférieure du fourreau 40. La paroi 42 du manchon supérieur 28 délimitant l'alésage destiné à recevoir le fourreau 40 est ouverte sur sa périphérie pour former une fente longitudinale 43 destinée au passage de la pièce de contact 41.The sheath 40 is extended at its lower end by a contact piece 41 intended to come to press the lever 26 to train it in tilting then, after jamming of the push rod 15, moving along the axis X at the same time as the push rod 15. The contact piece 41 has a first part 44 which is connected to a end on the sleeve 40, extending radially outwards perpendicular to the X axis over a distance greater than the radius outer of the sheath 40, for connecting to a second part 46 extending obliquely downward away from the X axis, forming an angle of about 45 ° with it. Part Two 46 presents its lower end a sharp edge 47 intended to exert pressure in the vicinity of the radially outermost free end 48 (in the cutting plane of FIGS. 1 and 2) of the lever 26. The upper sleeve 28 is generally cylindrical of revolution around the X axis; he is bored from its upper end edge 39 over more than half of its length to receive the lower end of the sleeve 40. The wall 42 of the upper sleeve 28 delimiting the bore intended to receive the sheath 40 is open on its periphery to form a slot longitudinal 43 intended for the passage of the contact piece 41.

L'ensemble constitué par le levier 26 et les manchons inférieur 29 et supérieur 28 se déplace à l'intérieur d'une pièce de guidage 49 généralement tubulaire autour de l'axe X, ouverte vers le bas et fermée à sa partie supérieure, hormis un taraudage 63 centré sur l'axe X pour le passage d'une vis de réglage creuse 62, à l'intérieur de laquelle peuvent coulisser le fourreau 40 et la tige de poussée 15. La pièce de guidage 49 présente une extrémité inférieure 50 épaulée, s'engageant dans la gorge annulaire 35 de la bague 31, au contact de la surface radialement interne de la paroi 34, jusqu'à butée de l'épaulement contre le bord supérieur de la paroi 34. La pièce de guidage 49 vient en appui, par sa tranche d'extrémité supérieure 51, contre l'ensemble indicateur de volume 21. Elle est ouverte sur sa longueur pour former une fente de guidage 52 de la partie 46 de la pièce de contact 41 et de l'extrémité 48 du levier 26, de sorte que ces dernières sont maintenues par la pièce de guidage 49 sensiblement à la verticale l'une de l'autre ; on assure ainsi que lorsque le fourreau 40 descend, l'arête 47 vient toujours en appui sur l'extrémité 48 du levier 26.The assembly constituted by the lever 26 and the sleeves lower 29 and upper 28 moves inside a guide piece 49 generally tubular around the X axis, open downwards and closed at its upper part, except for a thread 63 centered on the X axis for the passage of a hollow adjustment screw 62, inside which can slide the sheath 40 and the push rod 15. The guide piece 49 has a shouldered lower end 50, engaging in the groove annular 35 of the ring 31, in contact with the radially internal surface of the wall 34, until the shoulder stops against the upper edge of the wall 34. The guide piece 49 comes to bear, by its end edge upper 51, against the volume indicator assembly 21. It is open along its length to form a guide slot 52 of the part 46 of the contact piece 41 and the end 48 of the lever 26, so that these the latter are held by the guide piece 49 substantially at the vertical to each other; it is thus ensured that when the sheath 40 descends, the edge 47 always comes to bear on the end 48 of the lever 26.

Le levier 26 est représenté avec la tige de poussée 15 en perspective sur la figure 3. Il est principalement constitué par une plaquette s'étendant perpendiculairement à l'axe du perçage central 27, présentant une première partie 53 traversée en son centre par le perçage central 27 pour le passage avec un faible jeu de la tige de poussée 15 et une deuxième partie 54 prolongeant latéralement la première partie 53 pour servir d'appui à la pièce de contact 41. La première partie 53 est traversée par deux perçages 55 et 56 situés de part et d'autre du perçage central 27, servant chacun de logement à une bille 57 ou 58 retenue par sertissage dans la plaquette. Le plan P2 contenant les axes du perçage central 27 et ceux des perçages 55 et 56 recevant les billes 57 et 58 s'étend perpendiculairement à un plan médian P1 pour le levier 26, contenant l'axe du perçage central 27 et la direction selon laquelle s'étend la deuxième partie 54 du levier 26. Dans l'exemple décrit, la deuxième partie 54 présente, en coupe dans un plan parallèle au plan P2 une section rectangulaire.The lever 26 is shown with the push rod 15 in perspective in FIG. 3. It is mainly constituted by a plate extending perpendicular to the axis of the central hole 27, having a first part 53 crossed in its center by the hole central 27 for the passage with a small clearance of the push rod 15 and a second part 54 laterally extending the first part 53 to serve as support for the contact piece 41. The first part 53 is crossed by two holes 55 and 56 located on either side of the central bore 27, each serving as a housing for a ball 57 or 58 retained by crimping in the wafer. The plane P 2 containing the axes of the central bore 27 and those of the holes 55 and 56 receiving the balls 57 and 58 extends perpendicularly to a median plane P 1 for the lever 26, containing the axis of the central bore 27 and the direction in which the second part 54 of the lever 26 extends. In the example described, the second part 54 has, in section in a plane parallel to the plane P 2, a rectangular section.

Les billes 57 et 58 s'interposent axialement entre le manchon inférieur 29 et le manchon supérieur 28, et constituent des moyens de guidage pour guider le basculement du levier 26 lorsque la pièce de contact 41 prolongeant inférieurement le fourreau 40 appuie sur l'extrémité 48 de la deuxième partie 54. Ce basculement s'effectue autour d'un axe géométrique de rotation Y coupant perpendiculairement l'axe X, sensiblement à mi-épaisseur du perçage central 27. Un jeu plus ou moins prononcé, provoqué par l'usure, pour le passage de la tige de poussée 15 dans le perçage central 27 du levier 26 se traduit conformément à l'invention par un basculement plus ou moins grand du levier 26 autour de l'axe géométrique de rotation Y, jusqu'au coincement de la tige de poussée 15 contre les bords du perçage central 27. L'axe géométrique de rotation Y du levier 26 reste fixe durant l'opération de basculement de ce dernier.The balls 57 and 58 are interposed axially between the sleeve lower 29 and the upper sleeve 28, and constitute means of guide to guide the tilting of the lever 26 when the workpiece contact 41 extending below the sheath 40 presses the end 48 of the second part 54. This tilting takes place around a geometric axis of rotation Y intersecting the X axis perpendicularly, appreciably mid-thickness of the central bore 27. A play more or less pronounced, caused by wear, for the passage of the push rod 15 in the central bore 27 of the lever 26 is translated in accordance with the invention by a more or less large tilting of the lever 26 around of the geometric axis of rotation Y, until the rod of the thrust 15 against the edges of the central bore 27. The geometric axis of Y rotation of lever 26 remains fixed during the tilting operation of this latest.

Le manchon supérieur 28 présente, sur sa tranche d'extrémité supérieure 39, un bossage 60 convexe vers le haut, dont le sommet définit un contact ponctuel avec la tranche d'extrémité inférieure 61 de la vis de réglage 62. Cette dernière est traversée intérieurement par le fourreau 40 comme indiqué précédemment et elle est filetée extérieurement pour venir en prise, en partie inférieure, avec le taraudage 63 de la pièce de guidage 49. L'ensemble constitué par la vis de réglage 62 et la pièce de guidage 49 constitue le mécanisme 20 précité de réglage du volume à distribuer, en permettant de faire varier la course de descente du levier 26, donc celle de la tige de poussée 15 et de la tige de piston 5, à chaque action sur le poussoir 22, comme cela sera précisé dans la suite. La vis de réglage 62 présente à son extrémité supérieure une collerette 64 accessible de l'extérieur du boítier 1 par l'utilisateur, au travers d'ouvertures non représentées ménagées dans le boítier 1. La collerette 64 est avantageusement moletée sur sa surface radialement externe pour faciliter l'entraínement manuel en rotation de la vis de réglage 62 par l'utilisateur. Un frein peut également être rapporté sur la vis de réglage 62, pour exercer une force de friction avec le boítier 1 et empêcher un déréglage intempestif, au cours de l'utilisation, du volume sélectionné par l'utilisateur. La collerette 64 de la vis de réglage 62 tourne à l'intérieur d'une pièce 65 généralement cylindrique de révolution autour de l'axe X, munie d'ouvertures destinées à coincider avec celles du boítier 1 pour l'accès, depuis l'extérieur, à la collerette 64. Une rondelle de fermeture 66 est rapportée sur la tranche d'extrémité supérieure de la pièce 65. Cette dernière est percée à sa partie inférieure pour recevoir un écrou 67 traversé par la vis de réglage 62.The upper sleeve 28 has, on its edge upper end 39, an upwardly convex boss 60, the vertex defines a point contact with the lower end edge 61 of the adjusting screw 62. The latter is internally traversed by the sleeve 40 as indicated previously and it is threaded externally to engage, at the bottom, with the thread 63 of the guide piece 49. The assembly constituted by the screw adjustment 62 and the guide piece 49 constitutes the aforementioned mechanism 20 of adjustment of the volume to be distributed, allowing the stroke to be varied lowering of the lever 26, therefore that of the push rod 15 and of the rod piston 5, at each action on the pusher 22, as will be specified in the following. The adjusting screw 62 has at its upper end a flange 64 accessible from outside the housing 1 by the user, at through unrepresented openings made in the housing 1. The flange 64 is advantageously knurled on its radially surface external to facilitate manual rotation of the screw setting 62 by the user. A brake can also be added to the adjustment screw 62, to exert a friction force with the housing 1 and prevent inadvertent adjustment of the volume during use selected by the user. The collar 64 of the adjusting screw 62 turns inside a part 65 generally cylindrical of revolution around the X axis, provided with openings intended to coincide with those of the box 1 for access from the outside to the flange 64. A washer of closure 66 is attached to the upper end edge of the Exhibit 65. The latter is drilled in its lower part to receive a nut 67 through which the adjusting screw 62 passes.

L'ensemble indicateur 21 est connu en lui-même et ne sera pas décrit en détail. Il est, dans l'exemple représenté, du type comprenant trois tambours indicateurs du volume à distribuer, juxtaposés et engrènant les uns avec les autres et avec la vis de réglage 62, de façon connue en soi. Le volume à distribuer est indiqué à l'utilisateur par les tambours au travers d'une fenêtre transparente 68.The indicator assembly 21 is known in itself and will not be not described in detail. It is, in the example shown, of the type comprising three volume indicator drums to be distributed, juxtaposed and meshing with each other and with the adjusting screw 62, in a manner known per se. The volume to be dispensed is indicated to the user by the drums at the through a transparent window 68.

Le fonctionnement de la pipette est maintenant décrit plus particulièrement en référence aux figures 4 à 7.The operation of the pipette is now described more particularly with reference to Figures 4 to 7.

On a représenté sur la figure 4 le levier d'entraínement 26 dans sa position de repos. Le manchon supérieur 28 vient en butée axialement par le bossage 60 contre la tranche d'extrémité inférieure de la vis de réglage 62. Le manchon supérieur 28 est maintenu dans cette position par la force du ressort hélicoïdal 30, transmise au manchon supérieur 28 par l'intermédiaire des billes 57, 58 et du manchon inférieur 29. Le levier 26 s'étend sensiblement perpendiculairement à l'axe X et il n'y a pas de coincement de la tige de poussée 15 dans le perçage central 27. Le fourreau 40 est élastiquement sollicité vers le haut par le ressort 25. Il est retenu à l'intérieur de la vis de réglage 62 par butée de la pièce de contact 41 contre l'extrémité inférieure de celle-ci.There is shown in Figure 4 the drive lever 26 in its rest position. The upper sleeve 28 abuts axially by the boss 60 against the lower end edge of the adjusting screw 62. The upper sleeve 28 is held in this position by the force of the helical spring 30, transmitted to the sleeve upper 28 via balls 57, 58 and the lower sleeve 29. The lever 26 extends substantially perpendicular to the axis X and it there is no jamming of the push rod 15 in the central bore 27. The sheath 40 is resiliently biased upwards by the spring 25. It is retained inside the adjusting screw 62 by the workpiece stop contact 41 against the lower end thereof.

On a représenté sur la figure 5 le fourreau 40 du poussoir 22 au terme d'une première course, appelée course de confort, d'une distance B depuis la position de repos du fourreau 40 jusqu'à ce que l'arête 47 contacte le levier 26. Lorsque l'utilisateur continue sa poussée sur le bouton de manoeuvre 23, c'est-à-dire au terme de la course de confort, le levier 26 est entraíné en basculement autour de l'axe géométrique Y jusqu'au coincement de la tige de poussée 15 dans le perçage central 27. Comme indiqué plus haut, le mouvement de basculement s'effectue sans glissement sur la tige de poussée 15 autour de l'axe Y. Le manchon inférieur 29 ne bouge donc pas pendant le basculement du levier 26. Lorsque l'utilisateur appuie davantage sur le bouton de manoeuvre 23, le fourreau 40 entraíne, par l'intermédiaire de la pièce de contact 41, le levier 26 vers le bas, et le mouvement de ce dernier s'accompagne du mouvement de la tige de poussée 15, en raison du coincement de cette dernière dans le perçage central 27. Le mouvement vers le bas du levier 26 est transmis au manchon inférieur 29 par les billes 57 et 58, et ce dernier se déplace vers le bas à l'encontre du ressort hélicoïdal 30, jusqu'à butée de la tranche d'extrémité inférieure 70 du manchon inférieur 29 contre la tranche d'extrémité supérieure 71, plane et généralement perpendiculaire à l'axe X, de la partie centrale 33 de la bague 31. La tige de poussée 15 est descendue d'une distance A correspondant à la distance initiale entre la tranche d'extrémité inférieure 70 du manchon inférieur 29 et la tranche d'extrémité supérieure 71 de la partie centrale 33 de la bague 31. La tige de poussée 15 entraíne dans sa descente la tige de piston 5 et un volume de liquide prédéterminé est expulsé au travers de l'orifice 4'. Lorsque l'utilisateur relâche sa pression sur le bouton de manoeuvre 23, le levier 26 remonte seul, indépendamment de la tige de poussée 15, du fait de l'absence de coincement de cette dernière dans le perçage 27 quand la pièce de contact 41 n'exerce pas une pression sur l'extrémité 48. Le levier 26 est rappelé par le ressort hélicoïdal 30 vers sa position au repos correspondant à la venue en butée du manchon supérieur 28 contre la tranche d'extrémité inférieure 61 de la vis de réglage 62.FIG. 5 shows the sheath 40 of the pusher 22 after a first race, called a comfort race, a distance B from the rest position of the sleeve 40 until the edge 47 contacts lever 26. When the user continues to push on the operating button 23, that is to say at the end of the comfort stroke, the lever 26 is driven in tilting around the geometric axis Y until the push rod 15 is jammed in the central bore 27. As indicated above, the tilting movement takes place without sliding on the push rod 15 around the Y axis. The sleeve lower 29 therefore does not move during the tilting of lever 26. When the user presses the operating button 23 more, the sheath 40 drives, through the contact piece 41, the lever 26 downwards, and the movement of the latter is accompanied by the movement of the push rod 15, due to the jamming of this last in the central hole 27. The downward movement of the lever 26 is transmitted to the lower sleeve 29 by the balls 57 and 58, and the latter moves down against the coil spring 30, until it stops of the lower end edge 70 of the lower sleeve 29 against the upper end edge 71, flat and generally perpendicular to the X axis, from the central part 33 of the ring 31. The rod thrust 15 has descended by a distance A corresponding to the distance initial between the lower end edge 70 of the lower sleeve 29 and the upper end edge 71 of the central part 33 of the ring 31. The push rod 15 drives down its piston rod 5 and a predetermined volume of liquid is expelled through the orifice 4 '. When the user releases his pressure on the operating button 23, the lever 26 rises alone, independently of the push rod 15, due to the absence of jamming of the latter in the hole 27 when the contact piece 41 does not exert pressure on the end 48. The lever 26 is returned by the coil spring 30 to its rest position corresponding to the abutment of the upper sleeve 28 against the lower end edge 61 of the adjusting screw 62.

En agissant sur la vis de réglage 62, l'utilisateur peut modifier l'écart initial entre la tranche d'extrémité inférieure 70 du manchon inférieur 29 et la tranche d'extrémité supérieure 71 de la partie centrale 33 de la bague 31, donc la distance A et le volume qui sera dispensé lors de la pression suivante exercée sur le bouton de manoeuvre 23.By acting on the adjustment screw 62, the user can change the initial gap between the lower end edge 70 of the lower sleeve 29 and upper end edge 71 of the part central 33 of the ring 31, therefore the distance A and the volume which will be dispensed during the next pressure on the operating button 23.

De préférence, comme représenté plus particulièrement sur les figures 8 à 10, le bouton de manoeuvre 23 comporte deux parties assemblées de façon télescopique l'une sur l'autre. Plus précisément, le bouton de manoeuvre 23 comporte une partie inférieure 81 alésée en 82 pour venir s'emmancher sur la tranche d'extrémité supérieure du fourreau 40, jusqu'à butée de celui-ci dans le fond de l'alésage 82. Ce dernier est bordé extérieurement, vers le bas, par une paroi cylindrique 83 formant avec le fourreau 40 une gorge annulaire 84 ouverte vers le bas pour recevoir l'extrémité supérieure du ressort 25. Ce dernier travaille en compression et s'interpose élastiquement entre le fond de la gorge 84 et la rondelle de fermeture 66, traversée en son centre par le fourreau 40. Le bouton de manoeuvre 23 comporte également une partie supérieure 80, qui est montée à coulissement selon l'axe X sur la partie inférieure 81. Cette dernière est munie à son extrémité supérieure de languettes de retenue 86 présentant chacune, du côté radialement externe, une dent formant saillie, propre à venir en butée contre un épaulement 87 formé sur la surface radialement interne de la partie supérieure 80, pour retenir axialement cette dernière. Un ressort hélicoïdal 88 travaillant en compression est monté à l'intérieur de la partie supérieure 80 pour s'interposer élastiquement entre la face frontale supérieure 89 de la partie inférieure 81 et le fond 90 de la partie supérieure 80, et solliciter élastiquement cette dernière vers le haut jusqu'à butée des dents des languettes 86 contre l'épaulement 87.Preferably, as shown more particularly on Figures 8 to 10, the operating button 23 has two parts telescopically assembled one on top of the other. More specifically, the operating button 23 has a lower portion 81 bored at 82 to come and fit on the upper end edge of the sleeve 40, until it stops in the bottom of bore 82. This the latter is bordered on the outside, downwards, by a cylindrical wall 83 forming with the sheath 40 an annular groove 84 open downwards to receive the upper end of the spring 25. The latter works in compression and elastically interposed between the bottom of the groove 84 and the closing washer 66, crossed in its center by the sheath 40. The operating button 23 also includes an upper part 80, which is slidably mounted along the X axis on the lower part 81. The latter is provided at its upper end with tabs of retainer 86 each having, on the radially outer side, a tooth protruding, suitable for abutting against a shoulder 87 formed on the radially internal surface of the upper part 80, to retain axially the latter. A helical spring 88 working in compression is mounted inside the top 80 for to intervene elastically between the upper front face 89 of the lower part 81 and the bottom 90 of the upper part 80, and apply elastically the latter up until the teeth of the tabs 86 against the shoulder 87.

Avant d'utiliser la pipette, on remplit la seringue 2 d'un liquide à distribuer, en immergeant l'embout tronconique 4 dans le liquide à prélever puis en faisant remonter manuellement à l'aide du doigt d'entraínement 13 la tige de piston 5 dans le logement 10. La tige de poussée 15 remonte librement à l'intérieur du fourreau 40 du poussoir 22, le levier 26 étant dans sa position de repos.Before using the pipette, fill syringe 2 with a liquid to be dispensed, by immersing the tapered tip 4 in the liquid to collect and then manually raise with the finger 13 the piston rod 5 in the housing 10. The rod thrust 15 rises freely inside the sheath 40 of pusher 22, the lever 26 being in its rest position.

Pour distribuer un volume prédéterminé de liquide, sélectionné en tournant la collerette 64, et indiqué par les tambours de l'ensemble d'affichage 21, l'utilisateur appuie sur la partie supérieure 80 du bouton de manoeuvre 23. La force de poussée est transmise par l'intermédiaire du ressort 88 à la partie inférieure 81, donc au fourreau 40, et ce dernier se déplace vers le bas jusqu'à butée du manchon inférieur 29 contre la bague 31. Le ressort 25 de rappel du fourreau 40 dans sa position de repos est alors comprimé. Si l'utilisateur continue à appuyer sur le bouton de manoeuvre 23, la partie supérieure 80 vient recouvrir la partie inférieure 81 comme représenté sur la figure 10. En fait, l'utilisateur ne ressent que le ressort 88 est comprimé seulement après que le manchon inférieur 29 ait atteint la bague 31. On est ainsi assuré que l'utilisateur entraíne le bouton de manoeuvre 23 sur une distance suffisante pour que la tige de poussée 15 soit entraínée sur la totalité de la course A vers le bas. Quand l'utilisateur commence à relâcher le bouton de manoeuvre 23, le manchon inférieur 29 reste encore en butée le temps de la détente du ressort 88. On limite ainsi les à-coups sur la tige de poussée 15 et on assure la délivrance dans son intégralité du volume de liquide à distribuer. La constante de raideur du ressort 88 est supérieure à celle des ressorts 25 et 30. La constante de raideur du ressort 25 est supérieure à celle du ressort 30.To dispense a predetermined volume of liquid, selected by turning the flange 64, and indicated by the drums of the display assembly 21, the user presses on the upper part 80 of the operating button 23. The pushing force is transmitted by through the spring 88 at the lower part 81, therefore at the sheath 40, and the latter moves down to the stop of the lower sleeve 29 against the ring 31. The return spring 25 of the sleeve 40 in its position rest is then compressed. If the user continues to press the operating button 23, the upper part 80 covers the part lower 81 as shown in FIG. 10. In fact, the user does not feels that spring 88 is compressed only after the sleeve lower 29 has reached the ring 31. It is thus ensured that the user drives the operating button 23 a sufficient distance so that the push rod 15 is driven over the entire stroke A down. When the user begins to release the operating button 23, the lower sleeve 29 remains in abutment for the time of relaxation of the spring 88. This limits jolts on the push rod 15 and ensures the complete delivery of the volume of liquid to be dispensed. The stiffness constant of spring 88 is greater than that of springs 25 and 30. The stiffness constant of spring 25 is greater than that of spring 30.

Finalement, l'invention permet d'obtenir une précision parfaitement constante de la pipette malgré une usure du perçage central 27 et de la tige de poussée 15. Elle n'est pas limitée à l'exemple de réalisation décrit. On peut notamment modifier la fixation de la seringue 2 sur le boítier 1 et les moyens de liaison entre la tige de piston 5 et la tige de poussée 15.Finally, the invention makes it possible to obtain a precision perfectly constant pipette despite wear of the central bore 27 and the push rod 15. It is not limited to the example of realization described. One can in particular modify the attachment of the syringe 2 on the housing 1 and the connecting means between the piston rod 5 and the rod thrust 15.

La figure 11 représente, en perspective, un mode de réalisation particulièrement avantageux des moyens de fixation de l'ensemble seringue 3 et tige de piston 5 à l'extrémité inférieure du boítier 1 de la pipette. Il s'agit d'une pince 100 qui a été spécialement conçue pour permettre la mise en place ainsi qu'un remplacement rapide de la partie basse de la pipette. La pince 100 est constituée par une pièce massique mise en place à l'extrémité inférieure du boítier 1 de la pipette dans la position illustrée par les coupes des figures 1a et des figures 12 et 13. Elle comporte une partie ouverte munie de deux branches élastiques 101 s'ouvrant vers l'extérieur pour faciliter le guidage et permettre l'introduction de l'extrémité de la tige de piston 5. Les faces intérieures des deux branches élastiques 101 sont reliées entre elles par une surface cylindrique 102 dans laquelle va s'immobiliser la queue de la tige du piston 5.FIG. 11 represents, in perspective, a mode of particularly advantageous embodiment of the fixing means of the syringe 3 and piston rod 5 assembly at the lower end of the housing 1 of the pipette. It is a clamp 100 which has been specially designed for allow the installation as well as a quick replacement of the part pipette bass. The clamp 100 is constituted by a mass piece put in place at the lower end of the pipette case 1 in the position illustrated by the sections of Figures 1a and Figures 12 and 13. It includes an open part provided with two elastic branches 101 opening towards the exterior to facilitate guidance and allow the introduction of the end of the piston rod 5. The inner faces of the two branches elastic 101 are connected together by a cylindrical surface 102 in which the tail of the piston rod 5 will stop.

Dans la pratique, il s'est avéré avantageux d'avoir recours à une surface cylindrique de diamètre intérieur légèrement supérieur, de l'ordre de 1/10 mm, à celui de la surface extérieure de la queue de la tige de piston.In practice, it has proven advantageous to use a cylindrical surface of slightly larger internal diameter, of about 1/10 mm, to that of the outer surface of the tail of the rod piston.

Comme illustré sur la figure 11, ces branches élastiques 101 sont localisées à la partie inférieure de la pince 100 qui dans sa partie médiane comporte un évidement destiné à permettre le montage et le démontage de la queue de piston. Cet évidement est délimité par trois surfaces généralement planes qui sont essentielles pour assurer le montage et la retenue de la queue de piston précédemment décrite plus en détails. Du côté de l'ouverture des branches 101 se trouve une surface d'épaulement 103 qui est constituée par une petite surface plane s'étendant dans l'axe longitudinal de la pipette et servant de surface d'accrochage et d'appui du disque supérieur de friction 17 de la queue de la tige de piston 5. La fonction d'accrochage de la surface d'épaulement 103 est illustrée par la position de l'ensemble seringue piston de la figure 12. Il s'agit de la position d'introduction de l'ensemble seringue piston, qui s'effectue latéralement et en position inclinée par rapport au bas du boítier de la pipette. La mise en place définitive de l'ensemble piston est obtenue par un simple pivotement de cet ensemble pour l'amener dans une position coaxiale par rapport à la pipette. A cet effet, la pince 100 comporte une surface transversale 104 qui n'est pas rigoureusement perpendiculaire à l'axe X de la pipette mais présente une légère inclinaison de quelques degrés créant ainsi un dégagement autorisant le pivotement du disque supérieur 17 de la tige de piston 5. Il ne s'agit donc pas à proprement parler d'une surface de butée ou d'appui.As illustrated in FIG. 11, these elastic branches 101 are located at the lower part of the clamp 100 which in its part center has a recess intended to allow mounting and disassembly of the piston tail. This recess is delimited by three generally flat surfaces which are essential for ensuring the mounting and retaining the piston tail previously described more in details. On the side of the opening of the branches 101 is a surface shoulder 103 which is constituted by a small flat surface extending in the longitudinal axis of the pipette and serving as a surface hooking and supporting the upper friction disc 17 of the tail the piston rod 5. The attachment function of the shoulder surface 103 is illustrated by the position of the plunger syringe assembly in FIG. 12. This is the insertion position of the plunger syringe assembly, which takes place laterally and in an inclined position relative to the bottom of the pipette case. The final installation of the piston assembly is obtained by a simple pivoting of this assembly to bring it in a coaxial position relative to the pipette. For this purpose, the clamp 100 has a transverse surface 104 which is not strictly perpendicular to the X axis of the pipette but has a slight inclination of a few degrees thus creating a clearance allowing the pivoting of the upper disc 17 of the piston rod 5. It is therefore not not strictly speaking of a stop or support surface.

Enfin, du côté opposé à l'ouverture des branches 101, la position médiane de la pince 100 comporte une surface longitudinale 105 d'appui transversal de la queue de la tige de piston. On constate sur la figure 13 qu'après basculement de l'ensemble seringue piston les différents disques de friction 17 viennent au contact de cette surface 105 le long de l'une de leurs génératrices. Bien entendu, pour parfaire la solidarisation, la pipette comporte en outre une pince métallique 106 d'élasticité appropriée bloquant la partie basse de la pipette dans sa position correcte de travail, comme illustré à la figure 13. Cette pince 106 a pour fonction essentielle de maintenir la seringue 2 en appui sur la collerette de maintien inférieure 107 du boítier de pipette, alors que la tige du piston 5 pourra se déplacer avec la pince 100 à l'intérieur du logement 10 de la pipette.Finally, on the side opposite the opening of the branches 101, the middle position of the clamp 100 has a longitudinal surface 105 transverse support of the tail of the piston rod. We can see on the Figure 13 that after tilting the plunger syringe assembly the different friction discs 17 come into contact with this surface 105 along one of their generators. Of course, to perfect the connection, the pipette further comprises a metal clamp 106 of suitable elasticity blocking the lower part of the pipette in its correct working position, as illustrated in figure 13. This clamp 106 has essential function of keeping syringe 2 pressed on the lower retaining flange 107 of the pipette case, while the rod piston 5 can move with the clamp 100 inside the housing 10 of the pipette.

La partie supérieure 108 de la pince 100 comprend des moyens de solidarisation avec l'extrémité supérieure de la tige de poussée 15 pour commander les déplacements longitudinaux de l'ensemble pince 100 et piston 5 dans ledit logement 10 de la pipette.The upper part 108 of the clamp 100 includes means of attachment to the upper end of the push rod 15 for controlling the longitudinal movements of the clamp assembly 100 and piston 5 in said housing 10 of the pipette.

Claims (7)

  1. A pipette for dispensing successive volumes of liquid by repeated action on a pushbutton (22), the pipette comprising:
    a housing (1) of oblong shape, incorporating a mechanism for adjusting the volume of liquid to be dispensed;
    a syringe (2) for mounting removably to one end of the housing (1), comprising a syringe body (3) provided with a fluid-passing orifice (4') and a piston rod (5) mounted to move inside said syringe body (3);
    a thrust rod (15) mounted to slide longitudinally in the housing, and to be removably connected at one end to said piston rod (5);
    a drive lever (26) for driving the thrust rod (15) and the piston rod (5) solely towards said liquid-passing orifice (4), the lever (26) extending transversely to the longitudinal axis (X) of the thrust rod (15) and being provided with a hole (27) through which the thrust rod (15) passes with a small amount of clearance, the lever (26) also being mounted with the ability to move inside the housing over a stroke that is adjustable in the longitudinal direction (X) of the thrust rod (15) between a rest position defined by an adjustable abutment of the adjustment mechanism and an end-of-stroke position defined by a fixed abutment (31), and being returned towards said rest position by resilient return means (30); and
    said pushbutton (22) being mounted to slide longitudinally inside the housing, being provided at one end extending outside the housing with a pushbutton (23) and being capable of acting via its other end on the lever (26) to tilt it obliquely relative to the thrust rod (15) and then to drive the thrust rod by wedging towards the fluid-passing orifice (4') together with the piston rod (5) so as to expel a predetermined volume of liquid as defined by the stroke of the lever (26) between said rest position and said end-of-stroke position, return movement of the lever (26) towards its rest position after each action on the pushbutton (22) taking place under drive from said resilient return means (30) while the piston rod (5) retains its position within the body (3) of the syringe (2);
    the pipette being characterized in that the lever (26), mounted to rotate about a geometrical axis (Y) that intersects the axis of said hole (27) perpendicularly and substantially halfway along the hole, is disposed on the thrust rod (15) between a bottom sleeve (29) and a top sleeve (28) slidably mounted on the thrust rod (15), and in that said lever has two surfaces of revolution centered on said geometrical axis (Y), said surfaces being disposed on either side of said hole (27) and being in contact with the top and bottom sleeves (28, 29), the bottom sleeve (29) coming into abutment against said fixed abutment (31) when the lever (26) reaches its end-of-stroke position.
  2. A pipette according to claim 1, characterized in that said surfaces of revolution are formed by balls (57, 58) crimped in holes (55, 56) through the lever (26).
  3. A pipette according to claim 2, characterized in that said pusher (22) includes a sheath (40) slidably mounted inside the housing and within which the pushrod (15) is free to slide, and in that it is provided at one end with a contact piece (41) having a sharp edge (47) designed to press on the lever (36) to tilt it about said geometrical axis (Y) and then to move it along the longitudinal direction (X) of the thrust rod (15).
  4. A pipette according to claim 3, characterized in that the adjustment mechanism includes an adjustment screw (62) for rotating in order to adjust the stroke of the lever (26) and the volume dispensed each time the pusher (22) is actuated, said adjustment screw (62) having the sheath (40) and the pushrod passing through the inside thereof, and meshing with a volume-indicator mechanism (31), the adjustment screw (62) having an end edge (61) that defines said variable abutment, and in that the top sleeve (28) has an end edge suitable for coming into point contact with the end edge (61) of the adjustment screw (62) defining said variable abutment.
  5. A pipette according to any one of claims 1 to 4, characterized in that the pushbutton (23) includes a first portion (80) slidably mounted over a second portion (81), with a first return spring (88) being interposed therebetween, a second return spring of stiffness constant smaller than that of the first return spring being resiliently interposed between the housing (1) and said second portion (81) to return the pusher (82) resiliently away from said liquid-passing orifice (4'), the stiffness constant of said resilient return means (30) urging the lever (26) towards its rest position being smaller than the stiffness constants of the first and second return springs (88).
  6. A pipette according to any one of claims 1 to 5, characterized in that the syringe (2) and the piston rod (5) are removably fixed to the housing (1) of the pipette by means of a clamp (100) in the form of a part whose top portion (108) is secured to the bottom end of the thrust rod (15), whose middle portion includes a recess suitable for receiving the free top end of the piston rod (5), and whose bottom portion includes resilient branches (101) enabling the piston rod (5) to be inserted therein and to be held thereby, and in that the bottom end of the housing includes means (106, 107) suitable for removably securing the body (3) of the syringe (2) while leaving the clamp (100) and the piston rod (5) free to slide.
  7. A pipette according to claim 6, characterized in that the middle portion of the clamp (100) includes a recess defined by the free top faces of the clamps 101, by a transverse surface (104) and by a longitudinal surface (105).
EP95927786A 1994-08-16 1995-08-16 Pipette for distributing successive volumes of a liquid Expired - Lifetime EP0776247B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9410035A FR2723700B1 (en) 1994-08-16 1994-08-16 PIPETTE FOR DISPENSING SUCCESSIVE LIQUID VOLUMES
FR9410035 1994-08-16
PCT/FR1995/001084 WO1996004991A1 (en) 1994-08-16 1995-08-16 Pipette for distributing successive volumes of a liquid

Publications (2)

Publication Number Publication Date
EP0776247A1 EP0776247A1 (en) 1997-06-04
EP0776247B1 true EP0776247B1 (en) 1998-11-04

Family

ID=9466320

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95927786A Expired - Lifetime EP0776247B1 (en) 1994-08-16 1995-08-16 Pipette for distributing successive volumes of a liquid

Country Status (8)

Country Link
US (1) US5770159A (en)
EP (1) EP0776247B1 (en)
JP (1) JP3772348B2 (en)
CN (1) CN1158579A (en)
DE (1) DE69505827T2 (en)
FI (1) FI970642A (en)
FR (1) FR2723700B1 (en)
WO (1) WO1996004991A1 (en)

Families Citing this family (37)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2762671B1 (en) * 1997-04-29 1999-07-16 D Autry Eric Marteau DEVICE FOR DISPENSING SUCESIVE VOLUMES OF LIQUID WITH MAGNETIC HANGING ELEMENT
DE19963141A1 (en) * 1999-12-24 2001-07-12 Brand Gmbh & Co Kg Pipette for a pipetting system
FR2807341B1 (en) * 2000-04-07 2002-07-12 Gilson Sa PIPETTE FOR COLLECTING LIQUID SAMPLES WITH REMOVABLE EJECTOR
FR2807342B1 (en) 2000-04-07 2002-07-12 Gilson Sa CONCEAL EJECTOR PIPETTE
FR2807340B1 (en) 2000-04-07 2002-12-06 Gilson Sa PIPETTE FOR TAKING LIQUID SAMPLES WITH CONE EJECTOR MECHANISM
FR2807343B1 (en) * 2000-04-07 2002-12-06 Gilson Sa COLLECTION PIPETTE PROVIDED WITH MEANS FOR ADJUSTING THE VOLUME TO BE COLLECTED
US6749812B2 (en) * 2000-06-26 2004-06-15 Vistalab Technologies Automatic pipette detipping
AU2001275197A1 (en) * 2000-06-26 2002-01-08 Vistalab Technologies, Inc. Handheld pipette
EP1539352B1 (en) * 2002-07-23 2009-12-23 Protedyne Corporation Liquid handling tool having hollow plunger
US7093507B2 (en) 2003-05-12 2006-08-22 Bel-Art Products, Inc. Pipette control arrangement
DE102004038962B4 (en) * 2004-08-10 2007-10-31 Heraeus Kulzer Gmbh Multi-dose dispensers for small quantities and its use
FI20050340A0 (en) 2005-04-01 2005-04-01 Thermo Electron Oy Calibratable pipette
DE102005033378B4 (en) * 2005-07-16 2012-05-31 Eppendorf Ag pipette
USD620602S1 (en) 2008-01-03 2010-07-27 Vistalab Technologies, Inc. Pipette
DE102009034897A1 (en) * 2009-07-27 2011-02-03 Eppendorf Ag Syringe for use with dosing device that is utilized for e.g. receiving liquid, has cylindrical piston running portion connected with outlet, and coupling piece arranged at upper end of syringe piston for insertion into piston receiver
US8813584B2 (en) * 2009-07-27 2014-08-26 Eppendorf Ag Syringe, syringe family and metering device
US20100193548A1 (en) * 2010-03-08 2010-08-05 Poreda Stanley J Personal powder dispenser
FI20106185A0 (en) * 2010-11-11 2010-11-11 Thermo Fisher Scientific Oy Pipette with support
FI20106184A0 (en) * 2010-11-11 2010-11-11 Thermo Fisher Scientific Oy Kahvapipetti
US20130023790A1 (en) * 2011-07-19 2013-01-24 Schaeffer Jeremy R Biopsy device
USD706946S1 (en) 2011-12-22 2014-06-10 Eppendorf Ag Pipette
USD709623S1 (en) 2011-12-22 2014-07-22 Eppendorf Ag Pipette barrel
USD805651S1 (en) 2013-12-12 2017-12-19 Eppendorf Ag Flange for a pipette adapter
CN103623878B (en) * 2013-12-16 2014-07-23 山东大学齐鲁医院 Liquid-to-gas volumetric liquid transfer device
FR3026659B1 (en) * 2014-10-03 2016-12-23 Gilson Sas ERGONOMIC CONTROL PICK-UP PIPETTE
CN106586555B (en) * 2016-12-28 2022-03-29 上海原能细胞生物低温设备有限公司 Variable capacity suction device
WO2020110173A1 (en) * 2018-11-26 2020-06-04 ムロオカ産業株式会社 Dispenser
CN110100613B (en) * 2019-05-06 2021-06-22 朱丽萍 Automatic soil filling device for bonsai flowerpot
US11471878B2 (en) 2019-10-25 2022-10-18 Mettler-Toledo Rainin, LLC Powered positive displacement pipette
US11369954B2 (en) 2019-10-25 2022-06-28 Mettler-Toledo Rainin, LLC Powered positive displacement pipette assembly
US11389792B2 (en) 2019-10-25 2022-07-19 Mettler-Toledo Rainin, LLC Syringe for powered positive displacement pipette
US11911767B2 (en) 2019-10-25 2024-02-27 Mettler-Toledo Rainin, LLC Positive displacement pipette syringe identification system
US11446672B2 (en) * 2019-10-25 2022-09-20 Mettler-Toledo Rainin, LLC Powered positive displacement pipette syringe piston grasping mechanism
JP2022011167A (en) * 2020-06-29 2022-01-17 澁谷工業株式会社 Liquid suction and discharge device
CN111846379A (en) * 2020-08-03 2020-10-30 黄坤 Liquid-transfering gun head sequencing transfer device
CN113148648B (en) * 2021-06-04 2024-06-21 上海原能细胞生物低温设备有限公司 Freeze and deposit pipe suction control system
CN114681718B (en) * 2022-03-30 2024-03-19 宁波睿爱产品设计有限公司 Multiple quantitative injector

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2534857A (en) * 1949-08-30 1950-12-19 Crewe Mfg & Tool Co Ratchet mechanism for calking guns
BE562263A (en) * 1957-07-11
GB1011470A (en) * 1963-11-06 1965-12-01 Expandite Ltd Improvements relating to guns for applying viscous materials such as mastics
US4033484A (en) * 1975-03-26 1977-07-05 Ornsteen Chemicals, Inc. Hot melt cartridge adhesive gun
FR2432161A1 (en) * 1978-07-24 1980-02-22 Marteau D Autry Eric Piston type pipette to deliver repeated measured doses - esp. for immunology tests, has setting scale indicating vol. of dose
US4249419A (en) * 1979-01-05 1981-02-10 Thomas Bradley S Micropipette system
US4339058A (en) * 1979-12-07 1982-07-13 Wendt Robert J Apparatus for dispensing material from a containment vessel in preselected measured amounts
US4467942A (en) * 1982-04-29 1984-08-28 Yuuji Oshikubo Repeating dispenser
US4589870A (en) * 1984-02-21 1986-05-20 Indicon, Inc. Incremental actuator for syringe
CH671526A5 (en) * 1985-12-17 1989-09-15 Hamilton Bonaduz Ag
DE4341229C2 (en) * 1993-12-03 1995-09-07 Eppendorf Geraetebau Netheler Pipette system

Also Published As

Publication number Publication date
CN1158579A (en) 1997-09-03
FR2723700A1 (en) 1996-02-23
WO1996004991A1 (en) 1996-02-22
EP0776247A1 (en) 1997-06-04
FI970642A0 (en) 1997-02-14
DE69505827D1 (en) 1998-12-10
US5770159A (en) 1998-06-23
JP3772348B2 (en) 2006-05-10
DE69505827T2 (en) 1999-06-10
FR2723700B1 (en) 1996-11-15
JPH10504235A (en) 1998-04-28
FI970642A (en) 1997-04-14

Similar Documents

Publication Publication Date Title
EP0776247B1 (en) Pipette for distributing successive volumes of a liquid
EP0161980B1 (en) Make-up assembly, in particular for eye-lashes, for the use of a predetermined amount of make-up product
CA2301234C (en) Distributor comprising a plunger that is returned to its initial position by the tension of an elastic device
FR2802187A1 (en) DEVICE FOR DISPENSING A PRODUCT, COMPRISING A BOTTLE IN A CONTAINER
FR2798969A1 (en) DEVICE FOR LOCKING A POSITION OF A MOBILE PART IN RELATION TO A FIXED PART
EP1734851B1 (en) Electrical water heater
EP0032469A1 (en) Pipette with positive displacement
EP0014643B1 (en) Water injection device for a steam iron, and relevant steam iron
FR2836843A1 (en) Tipping jet perfume dispenser comprises pump with hollow piston rod activated by pivoting lever to which dispensing nozzle is fixed and connected by conduit to end coupled to rod
FR2467149A1 (en) DISPENSER-DOSER FOR PASTY AND LIQUID PRODUCTS
WO1991015409A1 (en) Device for automatic delivery of any product or object
FR2646652A1 (en) DEVICE FOR DELIVERING ANY PRODUCT CONTAINED IN A DEFORMABLE WALL TANK
FR2608903A1 (en) SKI BOOT WITH FOOT HOLDING SYSTEM CONTROLLED FROM OUTSIDE THE HULL
WO1990000072A1 (en) Syringe comprising a body with a variable-volume chamber and a needle device which can be mounted on said body
FR2597010A1 (en) LIQUID APPLICATOR HAVING IMPROVED LIQUID INTRODUCING MEANS
FR2714465A1 (en) Powder collection and distribution device.
FR3080783A1 (en) CONE EJECTION SYSTEM WITH IMPROVED ERGONOMICS FOR A PIPETTE
FR2881721A1 (en) Push button for pasty or liquid fluid e.g. liquid perfume, dispensing device, has nozzle body, connection socket, and lengthened tube that is deformed at level of its deformable sections in inclined position
FR2739087A1 (en) Adjustable flow packaging dispenser
FR2727670A1 (en) Dosing container for distributing liquid from reservoir, esp. used for cosmetic products
FR2562444A1 (en) Device for manual dispensing of a liquid product
EP3560396B1 (en) Device for attaching a wiper felt and assembly comprising same
FR2762671A1 (en) Syringe for dispensing successive measured volumes of liquid
FR2689774A1 (en) Subassembly for the elastic return of the retaining member of an alpine fastener.
FR2498418A3 (en) Mouthpiece for animal watering feed - has outer sleeve housing spring loaded valve, plunger and pivoted opening lever

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19970310

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): CH DE ES FR GB IT LI

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

17Q First examination report despatched

Effective date: 19971204

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): CH DE ES FR GB IT LI

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.

Effective date: 19981104

Ref country code: ES

Free format text: THE PATENT HAS BEEN ANNULLED BY A DECISION OF A NATIONAL AUTHORITY

Effective date: 19981104

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

REF Corresponds to:

Ref document number: 69505827

Country of ref document: DE

Date of ref document: 19981210

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)

Effective date: 19981120

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19990831

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19990831

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

REG Reference to a national code

Ref country code: GB

Ref legal event code: 732E

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20140812

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20140901

Year of fee payment: 20

Ref country code: GB

Payment date: 20140818

Year of fee payment: 20

REG Reference to a national code

Ref country code: DE

Ref legal event code: R071

Ref document number: 69505827

Country of ref document: DE

REG Reference to a national code

Ref country code: GB

Ref legal event code: PE20

Expiry date: 20150815

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION

Effective date: 20150815