FR2714119A1 - Manual spray pump with adjustable delivery used for pharmaceutical, perfume or cosmetic products - Google Patents

Abstract

The pump has an axial symmetry with a body (1) and piston (2) and a fixing assembly (6). The piston is mounted to slide in a sealed manner inside the body from its rest position and defines a pump chamber (3). The piston is moved upwards by a return spring (7) towards the fixing assembly. In the rest position the fixing assembly resists the force of the return spring. A regulator (9) is included that adjusts the volume of the pump chamber by the axial displacement of the piston in its rest position from the upper end of the pump body with respect to the fixing assembly.

Description

 The present invention relates to a manual dispensing pump with variable dose, and more precisely a manual pump intended for spraying or dispensing a fluid product such as a perfume, a cosmetic product, a pharmaceutical product or even a pasty product such as a cream. .

 For example, patents. French nos. 1,486,392 (Rudolph Albert) and 2,305,241 (Société Technique de Pulverisation - S.T.E.P.) disclose such pumps, comprising a cylindrical pump body in which slides a hollow piston provided with an outlet channel. The pump body and the piston define a pump chamber normally containing product to be sprayed or dispensed, and which communicates with a product reservoir through an inlet orifice. In addition, a valve stem disposed in the pump chamber is biased by a spring towards a valve seat formed on the piston, so as to close said outlet channel and to push the piston towards a rest position, where the volume of the pump chamber is maximum. The valve stem is integral with a differential piston which can slide on or in an internal cylindrical part of the pump body, which communicates with the product reservoir through the inlet port.

 When the piston is actuated against the spring stress, the differential piston cuts the communication between the pump chamber and the product tank, either by the action of an inlet valve integrated in the differential piston, or by fitting the piston differential in or on said inner cylindrical part of the pump body.

The actuation of the piston tends to decrease the volume of the pump chamber, so that an overpressure is created in said pump chamber: this overpressure acts on the differential piston by moving it away from the piston, against the stress of the spring, which causes the opening of the outlet channel of the piston by the valve stem, and the output of a dose of product contained in the pump chamber by said outlet channel, as the piston moves in the pump body.

 When the piston is no longer actuated, the spring pushes the valve stem towards the piston by closing the outlet channel, then pushes the piston back to its rest position.

During this movement, the volume of the pump chamber increases, so that a vacuum is created across said pump chamber. In the case where the differential piston has an inlet valve, the vacuum opens said inlet valve and causes the product to enter the pump chamber from the start of the piston return movement. Otherwise, that is to say if the communication between the pump chamber and the reservoir is cut off by fitting the differential piston onto or in the cylindrical inner part of the pump body, the entry of the product into the chamber pump is only done when the piston is again in its rest position, where the fitting ceases.

 In the pumps of the prior art, of the general type described above, the dose of product emitted is fixed. This dose depends in fact on two parameters, which are the section of the pump chamber and the stroke of the piston: the section of the pump chamber is of course fixed, and in the pumps of the prior art, the stroke of the piston is determined by an upper stop and a lower stop integral with the pump body, and therefore fixed.

 This can be a drawback, for example in the case where the pump contains a pharmaceutical product: with a conventional pump, it is not possible to vary the dose of product emitted, depending for example on the state or the age of the patient. In addition, with conventional pumps, two pumps having different doses necessarily make up different parts, and therefore - in the case of molded plastic parts - require that certain manufacturing molds be different: the pump manufacturer is therefore obliged to multiply the molds, which we know are very expensive.

 The present invention aims to avoid these drawbacks by providing a variable dose pump.

 The present invention therefore relates to a metering pump for dispensing a determined dose of a liquid or pasty product contained in a reservoir, said pump having substantially an axial symmetry and comprising a pump body, a piston and a fixed structural element. integral with said reservoir, said pump body having a lower end in communication with said reservoir and an upper end capable of being fixed at a position on said fixed structural element, said piston being mounted in leaktight sliding in said pump body by defining in position a pump chamber, the piston being biased by a return spring towards said fixed structural element which, in the piston's rest position, takes up the force exerted by said return spring, characterized in that it is provided means for adjusting the volume of the pump chamber by axial displacement of one of the two of the piston in rest position and the upper end of said pump body relative to said fixed structural element.

 According to a first practical embodiment, said fixed structural element is a spinner, said adjustment means comprising gripping means provided on said pump body near its upper end, said gripping means cooperating with an internal surface of said turret so as to allow relative axial displacement of the fixing position of the pump body in said turret.

Advantageously, the turret is made of a material which is less hard than that constituting the upper end of the pump body, said gripping means consisting of at least one protruding relief formed in said upper end of the pump body and adapted to bite into said internal surface of the tourette with a non-return harpoon effect.

As a variant, said gripping means consist of a screw thread, the internal surface of the spinner being smooth and receiving said screw thread by interference. The screw thread bites into the turner, forming a complementary screw thread by a self-tapping action.

In the first version using a harpoon effect, the pump body, just after mounting the pump and before adjusting the volume of the pump chamber, must be positioned relative to the spinner according to the direction of axial movement allowed by the relief projecting. The characteristic of the harpoon effect is indeed to allow displacement in one direction by preventing displacement in the other direction. On the other hand, in the screwed version, the pump chamber can be adjusted several times, depending on the doses of product to be administered.

According to a second practical embodiment, said pump body is fixedly mounted relative to said structural element, said adjustment means comprising an adjustment ferrule having a lower end against which said piston in the rest position is in abutment and an upper end provided with gripping means cooperating with a surface of said fixed structural element so as to allow relative axial displacement of the rest position of the piston and of the
Structure. Advantageously, the fixed structural element is a spinner made of a less hard material than that constituting the upper end of said adjusting ferrule, said gripping means consisting of at least one protruding relief formed in said upper end of the ferrule adjustment and adapted to bite into said surface of the tourette with a non-return harpoon effect. The principle used namely the harpoon effect and the same as that implemented previously for the pump body. However, it can be noted that a lowering of the pump body in the reservoir leads to an increase in the volume of the pump body, while a lowering of the top dead center of the piston leads to a decrease in the volume of this same pump chamber. This is why it seems superfluous, but nevertheless possible, to provide a pump with the two adjustment means jointly.

A variant of this second embodiment provides that the upper end of the adjustment ring has a threaded part received by interference in a smooth housing formed in said fixed structural element. Advantageously, the upper end of said adjusting ferrule has a crenellated profile adapted to receive a tool having a complementary attack profile for screwing said ferrule into the structural element. Another alternative of the invention provides that the fixed structural element is a sleeve integral with the pump body at its upper end, said sleeve being externally threaded and said ferrule having a coaxial adjustment ring connected to
The upper end of said ferrule extending outwardly, said ring being internally threaded to receive said bushing by screwing. In an embodiment detail, a latching means can prevent the complete exit of the shell from the pump body. Advantageously, said latching means is at least one elastic tongue integral with the sleeve, which cooperates with a relief integral with the ferrule to prevent the complete exit of said ferrule from the pump body. The sleeve and the tongue may be made of plastic and molded in one piece, the tongue being molded in the extension of the sleeve, then, during assembly of the ferrule, folded elastically towards said relief with which it cooperates. Advantageously, a reading ring secured to the pump body and an adjustment ring secured to the shell slide one on the other, one of these rings bears a mark and the other ring bears indications of dose volume. , so that the volume of a dose of product emitted by the pump corresponds substantially to an indication of volume in correspondence with the reference.

 In the versions using the harpoon effect, the adjustment of the volume of the pump chamber will be done after assembly, in the workshop using a machine capable of applying a force to the pump elements likely to cooperate by sliding. sufficient to adjust the volume in question to a desired value. It is not that the end user is unable to vary the volume of the pump chamber, but will not be able to adjust it precisely. By cons in the screwed versions, and especially in that using a reading ring, the adjustment can be made by any person depending on the application. The case using a crenel profile adjustment ferrule will be particularly useful for pharmaceutical applications. The pharmacist, using a specially adapted tool, will be able to adjust the volume of the room in pharmacies, that is to say, the dose of product to be administered to a patient according to his age, gender or the severity of the disease.

 Other characteristics and advantages of the invention will appear during the following detailed description of four embodiments of the invention, given by way of nonlimiting example with reference to the accompanying drawings.

In the drawings:
- Figure la is a sectional view of a pump according to a first form of
embodiment of the invention using an adjusting ferrule adjusted in
high position so as to define a maximum volume of the
pump,
FIG. 1b is a sectional view of the same pump illustrated in FIG.
with the adjusting ring in the low position corresponding to the minimum volume
the pump chamber,
- Figures 2a and 2b are sectional views of a pump according to a second
embodiment using an adjustable ferrule using
of a tool, in adjustment positions corresponding to those of Figures la
and lb,
- Figure 2c is a plan view of the crenellated adjusting ring of Figures 2a
and 2b,
- Figures 3a and 3b are sectional views of a pump according to a third
embodiment in which the adjustment means are provided for
the upper end of the pump body, and shown in positions
adjustment corresponding to those of FIGS. 1b and 1a,
- Figure 4 is an enlarged view of a priming cam part used
in the present invention in the embodiments illustrated in the
Figures I to 3,
- Figure 5 is a sectional view of a pump according to a fourth form of
embodiment in which the piston is in the maximum high position,
- Figure 6 is a plan view of the reading ring of the pump of the
figure 5,
- Figure 7 is an enlarged view of the latching means provided on the
pump of figure 5.

 The principle of the invention, that is to say the adjustment of the volume of the pump chamber, is not applicable to any type of pump. Indeed, it can only be adapted on pumps in which a relative displacement of the top dead center of the piston relative to the pump body will have the effect of varying the volume of the pump chamber. Figures 1 to 6 intended to illustrate the present invention, and which will be described in detail below, show two different types of pump incorporating the invention. Of course, other types of pumps not described capable of operating with the present invention are possible, without departing from the scope and the scope of the invention as defined by the claims.

 Figures I to 3 show three different embodiments of the present invention implemented on a particular type of pump incorporating both the essential characteristics of European patents Nos. 0 342 651 and 0 437 139. The first of these patents teaches 'use a piston member formed by a differential piston and a hollow piston interacting so as to allow a progressive filling of the pump chamber during the ascent of the piston member. As for the second patent, it makes it possible to solve the problem of priming the pump, that is to say of the initial filling of the pump chamber. For this, it is planned to interpose, between the piston and the differential piston, a cam piece which makes it possible to take off the differential piston from the piston at the point where the needle is engaged in the outlet valve seat when the piston arrives at the end of its travel in the pump chamber, so as to create an opening for the compressed air initially contained in the pump chamber to escape. A complete and precise description of a pump according to the invention incorporating these filling and priming means will be made with reference to FIG. 1, but will no longer be repeated, except for the characteristics which differ from those of FIG. 1, when describing Figures 2 and 3.

 Referring to FIG. 1, or more precisely to FIGS. 1 a and 1 b which represent a pump adjusted in maximum and minimum position of the pump chamber, it can be seen that the pump comprises, in a conventional manner, a cylindrical pump body I and hollow, in which a piston 2 slides so as to define a pump chamber 3.

 The piston 2 is extended towards the outside of the pump body I by a hollow push rod 2a, comprising a central channel 2b. The central channel 2b opens on the one hand outside the pump body 1, and on the other hand inside the pump body 1, forming a valve seat 2c on the piston 2. The push rod 2a, at its upper end, is capped with a push button 4 provided with a nozzle 41. On the other hand, the pump body 1 extends between an open end 11 through which the push rod passes 2a and a lower end forming a constriction lb which communicates with a reservoir of product by an inlet conduit Ic extended by a dip tube id. The upper open end 11 of the pump body 1 is snap-fastened into a dolly 6 which is formed with an internal housing specially designed to receive said reinforced end portion 11 of the pump body 1. During assembly, the body of the pump the pump is thus fixedly and definitively engaged without any subsequent adjustment possible. The term tourette is used here to designate the part allowing the fixed junction between the screwable or crimpable capsule 61 and the pump body 1. This part comprises a base 6a which is wedged between a seal 62 and the capsule 61, a cylindrical part 6b external and another internal cylindrical part 6c, the two cylindrical parts being joined by a spacer 6d in the form of a washer. The tourette 6 contrasts with the ferrule which consists of only a simple ring. The aforementioned housing in the tower is formed by the junction of the external cylindrical parts 6b and internal 6c.

In a detail of embodiment, the venting is carried out by a passage formed through the seal 62 and between the end part 11 of the pump body and the spinner forming the upper end 11 with reliefs allowing the air passage. The air is finally evacuated by passing between the internal cylindrical part 6c and the piston 2.

The pump body also comprises a tube 12 which projects upwards into the pump chamber 3 and which forms an inlet valve with a skirt 51 adapted to be fitted in leaktight and sliding manner on said tube 12 so as to isolate the pump chamber 3 from the tank. Said skirt 51 forms with a needle member 52 a differential piston 5 incorporating a filling valve and which has a double differential characteristic, as explained below. The needle member 52 has at its lower end a guide finger 521 having a shoulder on which bears a return spring 7 which rests on the lower part of the pump body 1. The upper end of the return spring which takes pressing on said shoulder also constitutes a stop for the skirt 51 which is then free to move axially over a certain distance between a position in contact with the spring corresponding to the maximum opening of the filling valve and a position of contact with the head of valve 522 of the needle in which the valve is closed hermetically
The needle member also forms a valve head 522 which is adapted to cooperate by sealed contact with the upper part 511 of the skirt 51, during the descent of the piston 2. The needle member extends upward by a rod whose end is chamfered so as to form a cone adapted to come into tight contact with the seat of the outlet valve 2c to isolate the pump chamber from the outside when the pump is at rest, and the return spring 7 urges the piston 2 on said valve seat 2c.

 The present embodiment of the invention also incorporates a cam part 8 as defined in European patent nO. 0 437 139. It takes the form of a structured washer with more or less salient reliefs as shown in FIG. 4. This part 8 is interposed between the piston 2 and the needle member 52. The formation of this part with more or less protruding reliefs allows the passage of the fluid but also of the air initially contained in the pump chamber.

 For a better understanding of this pump, it is useful to describe its operation during a priming actuation cycle and distribution of a liquid or pasty fluid. In the initial state, after assembly, your pump chamber contains only air. By pressing the press button 4, the piston 2 descends, driving the needle member 52 and the skirt 51. Once it has reached the end of its travel in the pump body, the piston 2 prints on the cam piece 8 a sufficient force to tilt it so that its internal edge 81 moves downward, greater than that of the upper edge 82, thereby causing the cone of the needle to detach from its valve seat 2c. An outlet passage for air is thus created. It can be seen that during the priming, the differential piston 5, consisting of the skirt 51 and the needle member 52, only assumes the functions of closing the filling valve and the inlet valve, this mechanism being described in more detail below.

When dispensing a liquid or a paste, the hydro-dynamic phenomena are more complex. In the embodiments of Figures I to 3, the skirt 51 remains permanently fitted on the tube 12, an upper rise of the skirt 51 having no effect on the volume of the pump chamber, since the product would be simply pushed back into the tank when the pump starts to operate. Thus, when a force is applied axially to the push button 4,
The needle member 52 and the skirt 51 begins by sealingly contacting each other by closing the annular passage which they define between themselves. This contact is achieved by the fact that the needle member 52 descends and that the skirt 51 remains in place due to its tight fitting by sliding on the tube 12. From this moment, the pressure rises in the pump chamber since the outlet and inlet valves are closed and the filling valve is also closed. A hydro-dynamic explanation is now useful for understanding how the differential piston works. Due to its constitution in two separate parts, the pressure inside the pump chamber must be used to both keep the filling valve closed and open the outlet valve during the descent phase of the piston 2. This is achieved by a judicious choice of the contact sections of the two component parts of the differential piston with the outside and the inside of the tank. Concretely, to allow the needle 52 to take off from its valve seat 2c, the force generated by the axial pressure result must be greater on the needle cone 52 than on its valve head 522 at the point of contact. with the skirt 51. Thus, once the pressure inside the pump chamber having reached a level sufficient to overcome the force of the spring 7, the needle will take off from its seat. This condition placed on the contact section is essential and clearly verified in FIGS. 1 to 3. As with the needle 52, the skirt 51 must satisfy the same condition, except that the difference in the forces generated by the axial result of the pressure must be directed upwards against the needle 52 so as to reinforce the tight contact between these two parts.

 To do this, the section in contact of the skirt 51 with the needle 52 must be greater than that of the skirt with the tube 12. This condition is also verified in FIGS. 1 to 3. As soon as the pressure has reached the predetermined value in depending on the stiffness of the return spring 7, the outlet valve opens and the product is evacuated by the pressure prevailing at this time inside the pump chamber to the outside. This fateful point is reached before the skirt 51 abuts in the bottom of the pump chamber; thus the priming cam part 8 does not intervene when there is presence of product in the chamber This part 8 is used in principle only once, when priming the pump, or perhaps again later if the pump were to prime. As soon as the pressure has dropped and the piston begins to rise, a vacuum is created, the filling valve between the skirt 51 and the needle 52 then opens and the product can thus be gradually sucked into the pump chamber, while the needle cone has returned to its contact position on the outlet valve seat 2c.

Filling continues until the piston is fully raised.

 The description of the means and operation of these two known filling devices is useful for understanding their actions carried out jointly. In particular, this arrangement is advantageous for the distribution of pasty products such as creams, because without the cam part, it is practically impossible to prime the pump, and without a two-part differential piston, it is practically impossible to fill. The combination of these two characteristics was chosen to apply the present invention, because it provides an optimum result.

Other types of pump could of course be used with the present invention, the essential characteristic of which will now be described and explained.

 Thus, according to the present invention, it is provided, in accordance with the embodiment of FIGS. 1a and 1b, that an adjusting ferrule 9 is interposed between the piston 2 and the spinner 6 to allow the adjustment of the high position of the piston 2 at rest, that is to say the adjustment of the volume of the pump chamber 3. This ferrule 9 is in the form of a ring having a lower end 91 against which the piston is in abutment when it is at rest and an upper end 92 provided with a protruding relief 921 adapted to bite into the internal cylindrical part 6c of the spinner 6. To do this, it is necessary that the spinner is made of a less hard material than the adjusting ferrule. By way of example, the constituent material of the spinner may be polypropylene and that of the POM adjusting ferrule. It may be noted that the protruding relief 921 of the adjusting ferrule 9 represents in section a toothed profile in the manner of a harpoon, so as to allow the displacement of the adjusting ferrule 9 relative to the spinner only in one direction.

In this case, this movement is only possible in the direction of FIG. 1b towards FIG. 1a, that is to say from the minimum top dead center of the piston towards the maximum top dead center of the piston, taking into account the shape of the raised relief shown in these figures.

Thus, after mounting the pump, the ferrule 9 is in the position of FIG. 1b, then using a pressing device, the volume of the pump chamber can be adjusted as desired, the volume maximum being reached for the position of the ferrule 9 as shown in FIG.

 The harpoon effect is particularly suitable for automatic adjustment in the workshop using an appropriate device. The molding of the shell 9 can be carried out in a very simple manner for a reduced cost. The fixing here is based on the difference in hardness of the materials used and not on complex mechanical means.

 Figures 2a and 2b show the same type of pump as that described and used in the embodiment of Figures la and lb. This new embodiment constitutes in a way a practical variant of the embodiment described above, in that the adjustment is also carried out by means of an adjustment ferrule. However, this last ferrule does not operate by harpoon effect, but has some elements of screw threads 922 as shown in FIGS. 2c. The adjustment is then made reversibly, unlike the harpoon-effect ferrule.

To allow the ferrule to be screwed on, the latter has at its upper end a crenellated annular profile 93 which is accessible using a tool of complementary shape from the top of the pump, after removal of a push button 4. The two figures 2a and 2b correspond to the same top dead center positions of the piston as those of figures la and lb. This variant allows the volume of the pump chamber to be adjusted manually, such as by a pharmacist, depending on the specific doses to be administered. Screwing, although more complicated to carry out by molding since it requires threading of the spinner, is advantageous because it allows the correction of errors due to its reversibility.

 While the previously described embodiments implement a separate part for adjusting the volume of the chamber, the embodiment of FIGS. 3a and 3b directly incorporates the adjustment means into the essential component parts of the pump, the type of which is the same. as that of Figures 1 and 2 commented in detail above. According to the invention, the upper end 11 of the pump body 1 is formed with a projecting relief 111 adapted to bite into the spinner 6 on its external cylindrical part 6b. To do this, it is necessary that the protruding relief 111 is formed from a material having a hardness greater than that of the spinner 6. The same respective materials as for the embodiments of FIGS. 1a and 1b can be used. After the pump assembly step, it has a configuration as shown in Figure 3b, corresponding to the maximum volume of the pump body chamb shown in Figure 3a. The direction of movement of the adjustment can be reversed by simply reversing the profile of the projecting relief 111 which achieves the harpoon effect.

 It may be noted that, compared to the embodiment using an adjusting ferrule 9, a rise in the pump body in the tower results in a reduction in volume of the pump chamber, while a rise in the adjusting ferrule 9 results in an increase in the volume of the chamber. The essential advantage of using an upper end 11 forming a harpoon mainly lies in the fact that an economy of a part is achieved, which implies one less molding step. Thus, the manufacture of the pump will hardly be subject to any additional cost linked to the additional capacity of volume adjustment of the chamber.

 Although not shown, it is also conceivable to provide a screw thread on the upper end 11 of the pump body 1 which cooperates with an internal thread of the spinner 6 formed on the internal face of its external cylindrical part 6b. This embodiment is also interesting, because it does not require the use of special tools for adjusting the volume, a simple relative rotation of the drum and the pump body making it possible to vary the volume of the chamber. On the other hand, the choice of materials used is simplified, since it is no longer necessary to ensure that one is harder than the other.

 A last particularly functional embodiment is illustrated in FIGS. 5 to 7. The type of pump used to implement the present invention is now different and is based on the principle set out in patent application n. 90 10076 of August 7, 1990. The pump shown in FIG. 5 uses a one-piece differential piston 5, unlike the pump previously described. The needle body and the skirt are therefore integral.

 The differential piston has an inlet valve to the pump chamber, consisting of an orifice 53 passing through the piston 5 and of a flexible annular seal 54 which surrounds the valve stem 6 and is adapted to be applied so watertight on the differential piston 5 by closing the orifice 53. Due to its elasticity, the seal 54 naturally tends to remain applied to the differential piston 5 by closing the orifice 53. The differential piston 5 also comprises a peripheral ring sealing (not shown) on which an outer periphery of the annular seal 54 can be applied in leaktight manner, by closing the orifice 53. Advantageously, a ring 54a integral with the annular seal 54 is fitted on the valve stem 52, so that it is pushed back towards the differential piston 5 by the push rod 2a when the valve stem 52 is applied against the valve seat 2c, which contributes to sealingly applying the annular seal e 54 on the differential piston 5.

 In the example of FIG. 5, the pump also comprises a cylindrical sleeve 13 externally threaded, with an internal diameter equal to the internal diameter of the pump body I, and one end of which has a collar 13a placed in contact with a collar 11a formed at the upper end of the pump body 1. The pump is fixed to the neck of the product reservoir by a metallic capsule crimped 61 around the collars 11a and 13a by trapping them, which secures the sleeve 13 and the pump body 1.

 An adjustment ring 15 internally threaded can be screwed onto the sleeve 13. From its end furthest from the sleeve 13, the adjustment ring 15 is extended internally by an annular part 16, itself extended towards the piston 2 by a ferrule 9 which surrounds the push rod 2a. Thus, the ferrule 9 serves as a stop for the piston 2 and determines its rest position in the pump body 1: the more the adjusting ring 15 is screwed onto the sleeve 13, the more the ferrule 9 sinks into the pump body 1 , and therefore the more the rest position of the piston 2 approaches the constriction of the pump body, which reduces the volume of the pump chamber 3 and therefore the volume of a dose. On the contrary, when the adjustment ring is unscrewed, the ferrule 9 moves towards the outside of the pump body 1, as does the rest position of the piston, which increases the volume of the pump chamber 3 and therefore the volume of a dose of sprayed or dispensed product.

 As shown in FIG. 7, the ferrule 9 can comprise an external peripheral groove 9a, and the sleeve 13 can comprise one or more elastic tabs 13b, advantageously three, which each extend from the end of the distant sleeve 13 from the pump body 1, inwards and towards the pump body 1, up to a tongue end 13d. The end 13d of each tab is applied elastically to the ferrule 9: thus, when the adjustment ring 15 is unscrewed, the ferrule 9 gradually leaves the pump body 1, until the ends 13d of the tongues 13 penetrate in the groove 9a and abut against an edge 9b, lower or close to the pump body, of the groove 9a. Thus, it prevents complete unscrewing of the adjusting ring 15 and therefore disassembly of the pump. From this position, when the adjusting ring 15 is screwed back on, the tongue 13b is pushed back towards the sleeve 13 by an edge 9c, higher or distant from the pump body, from the groove 9a, so that the tongue 13b does not not impede the movement of the ferrule 9 which sinks into the pump body 1.

 Advantageously, the tongues 13b are molded in one piece with the sleeve 13: at the end of molding, the tongues 13b are then in the extension of the sleeve 13, in the position shown in dotted lines in FIG. 4 then they are folded towards the inside and towards the pump body 1 during mounting of the adjusting ring 15 and of the ferrule 9 on the sleeve 13. In addition, the sleeve 13 may include internal recesses 13c in which the tongues 13b can be folded, this which prevents jamming of said tabs 13b between the sleeve 13 and the ferrule 9.

 The location of the volume of the pump chamber, which is necessary for the correct adjustment of said volume, can be done as shown in FIG. 6: a reading ring 18 can be snapped on or crimped onto the metal capsule 61 (see FIG. 5) with sufficient tightening so that said reading ring 18 cannot rotate relative to the pump body 1. The reading ring 18 surrounds the screwing ring 15, with a certain play. The reading ring 18 has a mark, by example a notch 18a produced at one end 18b, remote from the pump body, from the ring 18. The adjustment ring 15 has indications of dose volume, for example dose volumes expressed in milliliters, which are written on its surface external to locations such that, when such a volume indication is in the notch 18a of the reading ring 18, the volume of the dose chamber is effectively equal to the volume indication in the notch18a. Thus, it is easy for a user to adjust the dose volume as desired.

 As a variant, the pump body 1 can be fixed to the reservoir of the product by a turn 19 which snaps onto the collar 1a and can be screwed onto the neck of the reservoir. The sleeve 13 can then be formed in one piece with the spinner 19.

 The operation of this pump will not be described in detail, since the pump of Figures 1 to 3 operates on the same general principle. The step of pressurizing and evacuating the pump chamber is identical, except that the differential piston 5 is in one piece. However, this characteristic does not come into play during this stage. The skirt 51 and the needle organ 52 remain integral in the pump previously considered, and, in the pump now described, the annular seal 54 remains applied in leaktight manner to the differential piston 5 by closing the orifice 53, due to the high pressure in the pump chamber.

 When the user releases the push rod 2a, the spring 7 pushes the piston 2 towards the outside of the pump, which creates a vacuum in the pump chamber 3.

This vacuum causes the external periphery of the seal 54 to rise, which thus opens the orifice 53 of the differential piston 5. As the spring 7 pushes the piston 2 and the differential piston 5, the pump chamber 3 is fills again with product, sucked into the tank through the inlet port Ic of the pump. This movement stops when the piston 2 abuts against the ferrule 9.

 In FIG. 5, the pump body 1 does not have an air intake orifice, allowing the entry into the product reservoir of a volume of air equal to the volume of product taken by the pump in its phase suction. It goes without saying that the pump body I could incorporate such an air intake orifice, well known in the state of the art, without departing from the scope of the present invention.

 It is therefore clear that the position of the ferrule 9, adjustable by screwing or unscrewing the adjustment ring 15, directly influences the volume of the pump chamber 3, that is to say the volume of the dose of product emitted. at each actuation of the pump -, at least as long as the skirt 51 remains fitted on the tubular endpiece 12, since the volume of the dose chamber 3 is only defined from the moment when the skirt 51 is fitted on the tubular end piece 12. I1 is therefore not useful for the ferrule 9 to be able to move away from the constriction lb of the pump body beyond a position such that the skirt 51 is no longer fitted on the end piece tubular 12, since beyond this position the dose volume no longer increases. Optionally, the position of the ferrule 9 furthest from the constriction 1b of the pump body can be such that the skirt 51 is just disengaged from the tubular endpiece 12, as shown in FIG. 1.

 When adjusting the dose volume, if the dose volume is increased by unscrewing the adjustment ring 15, a vacuum is created in the pump chamber 3 if the skirt 51 is fitted onto the tubular end piece 12, - this which is the general case. The annular seal 54 therefore peels off from the differential piston 5 and a volume of product equal to the increase in the volume of the pump chamber 3 is drawn into said pump chamber through the orifice 53 of the differential piston 5. On the contrary, if the dose volume is reduced by screwing the adjusting ring 15, an overpressure is created in the pump chamber if the skirt is fitted on the tubular end piece, so that a volume of product equal to the reduction in volume from the pump chamber 4 is expelled through the channel 2b, as when the pump is actuated. Optionally, to avoid this untimely expulsion of product, it is possible to make this adjustment after having pressed the push rod 2a and emptying the pump chamber 3, by normal actuation of the pump, and by maintaining said push rod pressed into pump body 1 during adjustment.

Claims (13)

Claims:  1.- Metering pump for dispensing a determined dose of a liquid or pasty product contained in a reservoir, said pump having substantially axial symmetry and comprising a pump body (1), a piston (2) and a structural element fixed (6, 13) integral with said tank, said pump body (1) having a lower end in communication with said tank and an upper end (II) which can be fixed at a position on said fixed structural element (6, 13) , said piston (2) being slidably mounted in said pump body (1) by defining a pump chamber (3) in the rest position, the piston (2) being biased by a return spring (7) towards said fixed structural element (6, 13) which, in the piston rest position, takes up the force exerted by said return spring (7), characterized in that there are provided means for adjusting (9, 111) the pump chamber volume per displacement axial of one of the two of the piston (2) in the rest position and of the upper end (11) of said pump body (1) relative to said fixed structural element (6, 13).  2. A metering pump according to claim 1, in which said fixed structural element is a spinner (6), said adjustment means comprising gripping means provided on said pump body near the upper end (11). thereof, said gripping means cooperating with an internal surface (6b) of said tower (6) so as to allow relative axial displacement of the fixing position of the pump body (1) in said tower (6)  3. A dosing pump according to claim 2, in which the spinner (6) is made of a less hard material than that constituting the upper end (11) of the pump body (1), said gripping means consisting of at least one projecting relief (111) formed in said upper end (11) of the pump body (1) and adapted to bite into said internal surface (6b) of the spinner (6) with a non-return harpoon effect.  4. A metering pump according to claim 2, in which said gripping means consist of a screw thread, the internal surface of the spinner being smooth so as to receive said screw thread by interference.  5. A metering pump according to claim 1, in which said pump body (1) is fixedly mounted relative to said structural element (6, 13), said adjustment means comprising an adjustment ferrule (9) having one end. lower (91) against which said piston (2) in the rest position is in abutment and an upper end (92) provided with gripping means (921, 922, 15) cooperating with a surface of said fixed structural element (6, 13 ) so as to allow relative axial displacement of the rest position of the piston (2) and of the structural element (6, 13).  6. A dosing pump according to claim 5, in which the fixed structural element is a spinner (6) made of a less hard material than that constituting the upper end (92) of said adjusting ferrule (9). , said gripping means consisting of at least one projecting relief (921) formed in said upper end (92) of the adjusting ring (9) and adapted to bite into said surface (9c) of the spinner (6) with an effect non-return harpoon.  7. A metering pump according to claim 5, in which the upper end (92) of the adjusting ring (9) has a threaded part received by interference in a smooth housing formed in said fixed structural element (6).  8. A dosing pump according to claim 7, in which the upper end (92) of said adjusting ring (9) has a crenellated profile (93) adapted to receive a tool having a complementary attack profile for screwing. of said ferrule (9) in the structural element (6).  9. A metering pump according to claim 7, in which the fixed structural element is a sleeve (13) integral with the pump body (1) at its upper end (11), said sleeve (13) being externally threaded and said ferrule (9) having a coaxial adjustment ring (15) connected to the upper end (16) of said ferrule (9) extending externally, said ring (15) being internally threaded to receive said socket (13) by screwing.  10.- Manual pump according to claim 7, further characterized in that a latching means (13b) prevents the complete exit of the ferrule (9) out of the pump body (1).  11. A manual pump according to claim 10, further characterized in that said latching means is at least one elastic tongue (13b) integral with the sleeve (13), which cooperates with a relief (9b) integral with the ferrule (9) to prevent the complete exit of said ferrule (9) from the pump body (1).  12. A manual pump according to claim 11, further characterized in that the sleeve (13) and the tongue (13b) are made of plastic and molded in one piece, the tongue (13b) being molded in the extension of the sleeve (13), then, during assembly of the ferrule (9), folded elastically towards said relief (9b) with which it cooperates.  13. A manual pump according to claim 7, further characterized in that a reading ring (18) integral with the pump body (1) and the adjusting ring (15) integral with the ferrule (9) are arranged concentrically, one of these rings carries a mark (18a) and the other ring carries dose volume indications, so that the volume of a dose of product emitted by the pump corresponds substantially to a volume indication in correspondence with the reference (18a).