OSCILLATORY-ROTARY LIQUID DISPENSING DEVICE WITH SPRING, AND ASSOCIATED METHOD

Abstract

The present invention relates to a device for dispensing liquid product, comprising a fixed part and a moving part; the fixed part comprising an intake orifice, a delivery orifice, a body comprising a cavity into which said orifices open, said cavity being able to partially house the moving part, the remaining volume forming an emptying chamber; the moving part being able to move partially in the cavity of the fixed part and comprising a piston, a piston driving element, an axial spring, a duct extending along the circumference of the piston, said duct allowing positions that allow fluidic communication between the emptying chamber and just one of said orifices and allowing switchover positions in which all fluidic communication between the emptying chamber and each of said orifices is forbidden, a cam able to convert the rotation of the drive element into an oscillatory-rotary movement of the piston. The axial spring is able to absorb energy during a liquid intake phase and to restore same during a liquid delivery phase, said spring being positioned around the piston which is on the moving part situated inside the cavity of the body.

Description

FIELD OF THE INVENTION

The present invention relates to an oscillatory-rotary volumetric subassembly and to a device for volumetric pumping of a fluid.

PRIOR ART

The use of volumetric pumping devices for delivering (injection, infusion, oral, spraying.) fluids and/or powder is known, notably for medical, aesthetic, veterinary or food applications. In particular, in the medical field, different mechanical or electromechanical systems are known, subassemblies such as “syringe pump,” “cartridge pump devices,” peristaltic pumps, piston pumps, rotary pumps. In the case of pumps actuated by a motor, whether it is linear or rotary, when the fluid is to be transferred at a high speed and a high pressure, that is to say higher than 4 bar, this entails the use of a motor allowing one to operate at a high speed and capable of supplying a high force or a high torque.

In this field, the application EP1803934 is known, which relates to a pump including a stator, a rotor including an axial extension which slides and rotates at least partially in a rotor chamber of the stator, and at least first and second valves between an inlet and a rotor chamber, respectively between the rotor chamber and an outlet, which open and close as a function at least of the angular movement of the rotor. The pump includes cam elements interacting on the rotor and the stator and biasing means acting on the rotor in order to apply a force to the rotor in the axial direction of the stator cam element.

This prior art represented an insufficient advance for reducing the size of the oscillatory-rotary pump motors for integration in a portable device.

Also known is patent EP3025058A1 which describes an oscillatory-rotary subassembly for volumetric pumping of a fluid, which comprises a hollow body defining a cavity whose wall is passed through by two ducts, the piston defining with said cavity a working chamber and comprising a groove opening longitudinally into said working chamber, said piston being angularly movable in order to put said working chamber in fluidic communication with one and then none and then the other of said ducts, and alternately in longitudinal translation so as to vary the volume of said working chamber and then successively deliver said fluid, said piston bearing a sealing gasket formed by at least one sealing ring, a sealing half-ring and at least one sealing strip longitudinally connecting said sealing ring to said sealing half-ring.

Although this pump can be designed for small swept volumes and can withstand high pressures, it is necessary to use a very high rotation speed of the motor when one wishes to quickly administer a fluid. Moreover, in order to achieve this rotation speed, the acceleration time of the motor is not negligible with respect to the duration of ejection of the fluid dose delivered by the pump. The result is that the ejection speed is not constant in the course of the dose. This leads to motors of relatively large size for integration in a portable device.

Also known is patent EP2962714 which describes a micropump using an eccentric cam element which turns in a pump casing in order to sequentially open and close valves in the pump casing in order to withdraw the fluid from a reservoir and supply measured quantities of the fluid to a cannula orifice for administration to a patient. The micropump can be used in a disposable pump for continuous perfusion of drugs such as insulin.

The eccentric cam sequentially biases each valve actuator during a complete rotation of the piston. This prior art represented an insufficient advance for pulsed administration of liquid with a motor of small size. In addition, the restoring force on the sealing gaskets exerted by the valve springs has to be sufficiently high in order to ensure that the valve actuators do not open under the operating pressures of the micropump.

Other examples of volumetric pumping devices for delivering (injection, infusion, oral, spraying.) fluids and/or powder are also illustrated in documents DE202004 018603, DE1936358, FR1416519, WO2015/011384, US1866217, US2005/132879, US4850824, FR940128 and FR1463091.

SUMMARY

The present invention was developed in order to solve the aforementioned problems, in particular the ability to ensure ejection of product at a constant speed for a duration which can be less than 100 ms while reducing the size of the oscillatory-rotary pump motors in order to reduce their space requirement and ensure the miniaturization of the final device. In fact, the torque necessary to actuate a device of the type according to the invention is high and requires the use of an often bulky motor having a high energy consumption and thus limiting the miniaturization.

The present invention thus relates to a device for dispensing product in liquid form, comprising a fixed part and a movable part, the fixed part including an intake orifice, a delivery orifice, a body comprising a cavity into which said orifices open, said cavity being able to partially house the moving part, the volume formed between the surface of the cavity and the moving part defining an emptying chamber, the moving part being able to move partially in the cavity of the fixed part and including a piston, a piston driving element, an axial spring, a duct extending along the circumference of the piston, said duct on the one hand allowing positions that allow fluidic communication between the emptying chamber and just one of said orifices and on the other hand allowing switchover positions in which all fluidic communication between the emptying chamber and each of said orifices is forbidden, the device according to the invention including a cam able to convert the rotation of the driving element into an oscillatory-rotary movement of the piston, characterized in that the axial spring is able to absorb energy during a liquid intake phase and to restore same during a liquid delivery phase, said spring being positioned around the piston which is on the moving part situated in the cavity of the body.

Preferably, the axial spring used in the present invention is a helical spring in order to assist the motor in increasing the torque supplied during the delivery phase. Preferably, the helical spring can be taken away from the action of the motor. Advantageously, the helical spring allows simplicity of assembly.

In the present invention, the duct extending along the circumference of the piston is delimited by sealing lips in order to ensure the fluid-tightness between the piston and the body of the device, as well as between the different fluid circulation zones.

Preferably, said duct includes a delivery groove connecting the delivery orifice to the emptying chamber during the delivery phase and an intake groove connecting the intake orifice to the emptying chamber during the intake phase, said grooves being implemented so as to alternately put one of the orifices, the intake orifice or the delivery orifice, in fluidic communication with the emptying chamber or forbid any fluidic communication between said orifices and the emptying chamber during the rotation.

In one embodiment of the invention, the intake groove is in the form of a helical internal threading forming an angle α preferably identical to the angle of the slope of the cam in order to reduce the dead volume.

Preferably, the delivery groove extends on an axis co-linear with that of the cam abutment and forms with the longitudinal axis of the piston an angle β such that 0° ≤ β ≤ 70°, this in order to optimize the operation of the device during the delivery step.

Also preferably, the angle β is an angle of 0°.

In another embodiment, the intake orifice and the delivery orifice are angularly separated by an angle between 170° and 190° on a plane perpendicular to the longitudinal axis of the piston (22) in order to simplify the design of the sealing gasket taking into consideration its optimal moldability. Preferably, the intake orifice and the delivery orifice are substantially at 180° with respect to one another on this same plane.

The present invention also relates to a method for administering a fluid, including four successive steps. During a first intake step, the device according to the invention is actuated to drive the rotation of the cam in order to obtain an oscillatory-rotary movement of the piston, and during said oscillatory-rotary movement, the intake orifice is in communication with the duct, and the delivery orifice is covered so as to obtain the filling of the emptying chamber and the compression of the axial spring between the cam and a spring support. During a first intermediate step, also referred to as maximum switchover step, after the intake step, the two orifices, the intake orifice and delivery orifice, are covered and non-communicating, and during which the emptying chamber is in its maximum volume. During a third delivery step, the axial spring is decompressed in order to bring about the translation of the piston, in order to empty the emptying chamber through the delivery groove in fluidic communication with the delivery orifice. During a second intermediate step, also referred to as minimum switchover step, the two orifices, the intake orifice and the delivery orifice, are covered and non-communicating and the piston is at the end of the stroke in the cavity of the body of the fixed part, and the axial spring is released.

Preferably, the height of the abutment of the cam is adjustable in order to vary the volume of liquid ejected from the emptying chamber through the delivery orifice. This makes it possible to vary the amplitude and adjust the maximum volume.

The present invention also relates to any medical apparatus containing the device described here or using the method for administering liquid described here.

The present invention also relates to a fluid cartridge including a fluid circuit and a dispensing device according to the invention.

DEFINITIONS

In the present invention, the terms below are defined as follows:

• “inner threading angle α” relates to the tilt of the helical intake groove with respect to the axis of the piston.
• “duct” indicates the path travelled by the liquid; in the preferred embodiment, it involves an intake groove having the form of a helical inner threading and a delivery groove, the two grooves being situated on the periphery of the piston
• “substantially” in the context of the invention means that one is within the margin of error corresponding to the precision of the tool for measuring the value.
• “fluid,” in the invention, the fluid is a gas or a liquid, it is preferably a liquid.
• “Cartridge:” Detachable casing capable of including a fluid dispensing device.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a longitudinal section of the device according to the invention, wherein the piston is at the end of the stroke in the cavity of the body of the fixed part, the chamber is emptied, and the axial spring is released (minimum switchover step).

FIG. 2 is a perspective view of the device according to the invention, wherein the piston is at the end of the stroke in the cavity of the body of the fixed part, the chamber is emptied and the axial spring is released (minimum switchover step). The cam support of the fixed part is not illustrated.

FIG. 3 is a longitudinal section of the assembly consisting of the body of the fixed part, of the cam, of the piston, of the spring, of the sealing gasket and of the orifices, when the piston is at the end of the stroke and the emptying chamber is emptied (minimum switchover step).

FIG. 4 is a front view of the assembly consisting of cam, piston, sealing gasket and duct, when the piston is at the end of the stroke and the emptying chamber is emptied (minimum switchover step).

FIG. 5 is a perspective view of the assembly illustrated in FIG. 4, wherein the emptying chamber is filled with a liquid product. This figure is a perspective view of the assembly consisting of cam, piston, sealing gasket and duct.

FIGS. 7a, 7b, 7c and 7d illustrate the development of the cylindrical peripheral surface defined by the sealing gasket and the sealing lips. These four figures show the configurations of the intake and delivery orifices as a function of the intake and delivery grooves during the four operational steps of the device.

FIG. 6 is a longitudinal section of the device according to the invention, wherein the emptying chamber is filled with liquid and the axial spring is compressed.

FIGS. 7e, 7f, 7g and 7h illustrate the development of the outer peripheral surface of the cam. These four figures show the configurations of the cam as a function of the cam support during the four operational steps of the device.

FIGS. 8a to 8d are front views of the assembly including the end of the piston and the sealing gasket, illustrating four different configurations of the assembly during a complete rotation of the moving part, in which the delivery orifice is represented in a projected view.

FIGS. 8e to 8h are front views of the assembly including the end of the piston and the sealing gasket, which show the opposite side from that illustrated in FIGS. 8a to 8d, respectively, and wherein the intake orifice is represented in a projected view.

DETAILED DESCRIPTION

The present invention relates to a device for dispensing liquid product and will be understood better upon reading the following figures which are an illustration without any intention of limiting the invention.

As detailed in FIG. 1, the body 13 of the fixed part 1 is hollow and comprises at least two cylindrical cavities 151, 152 having longitudinal axis (A) and different diameters, which are connected to one another by a shoulder 18 and communicate with one another thus defining the cavity 15 which is able to house the moving part 2. The cylindrical cavity 152 of large diameter communicates with the outside as well as with the cylindrical cavity of small diameter 151; this cavity is configured to partially house a spring support 16 and to completely house the helical spring 23 and the cam 25. It should be noted that the coils of the helical spring 23 are wound around the moving part 2; this spring rests on the spring support 16 which constrains it during the intake phase. The release of the spring 23 makes it possible to provide additional energy to the motor for moving the piston 22 in order to empty the emptying chamber 27.

As can be seen in FIG. 1, the spring 23 is positioned around the piston 22. Having the spring around the piston 22 provides a reinforced stability to the device. In fact, depending on the dimensioning and the stiffness of the selected spring 23, it is possible that a buckling phenomenon of the spring 23 is observed during its compression. The centering around the piston 22 makes it possible to avoid this problem. Advantageously, this configuration moreover allows a simplicity of assembly and a greater compactness by capitalizing on the presence of the bearing surface between the spring support 16 (pump body) and the piston 22. The centering of the spring 23 around the piston 22 has yet other advantages such as the placement and the centering of the means for reducing frictional forces between the spring 23 of the bearing surfaces. Generally, the centering of the spring 23 in axial position allows a better distribution of the mechanical stresses on the piston 22.

In a preferred embodiment, the release of the spring makes it possible to provide energy necessary for moving the piston in order to empty the emptying chamber 27. In FIG. 1, this makes it possible to move the piston 22 and to empty the emptying chamber 27. This makes it possible to reduce the necessary torque of the latter and thus to reduce its size and its space requirement.

Moreover, the cam 25 comprises an inclined ramp 251 which is able to slide on a cam support 14 of the fixed part 1. The small-diameter cylindrical cavity 151 has an end communicating with the large-diameter cylindrical cavity 152, and a closed end. The cylindrical cavity 151 is intended to partially house the piston 22. The sealing between the piston and the small-diameter cylindrical cavity 151 is provided by the piston sealing gasket 29. The cylindrical cavity 152 can have, for example, a variable diameter in order to adapt to the spring support 16 and to the piston driving element 21.

In reference to FIG. 2, the piston driving element 21 is a cylinder with longitudinal axis A, having a form suitable for housing a motor, comprising, for example, a flat section and a cylindrical cavity; it is connected to the moving part 2 via a connection means 30; said connection means 30 can be of any form complementary to the corresponding recess located in the piston 22; a flat or cross-shaped form can be considered, for example. The piston driving element 21 can be driven preferably by a motor, but any other means for providing mechanical energy can be considered. It is specified that this element is preferably driven by a motor, but any other means of supplying mechanical energy can be considered, keeping in mind that the presence of the axial spring will make it possible to reduce the required energy contribution. This is true provided that the means for supplying energy has sufficient impulse.

In reference to FIG. 3, the sealing gasket 29 and the duct 24 are implemented so as to alternately, that is to say successively one after the other with possibility of intermediate steps, put one of the orifices, namely the intake orifice 11 or the delivery orifice 12, respectively, in fluidic communication with the emptying chamber or forbid any communication between the intake or delivery orifices 11, 12, respectively, and the emptying chamber 27. In the example illustrated in FIG. 3, the delivery orifice 12 is in fluidic communication with the emptying chamber 27. Communication between the emptying chamber 27 and the intake orifice 11 is forbidden. More particularly, the configuration of the duct 24 (visible in FIG. 4) and of the sealing gasket 29 allows fluidic communication between one of the orifices, namely the intake orifice 11 or the delivery orifice 12, and the emptying chamber during the intake and delivery steps; this is illustrated in FIGS. 7a and 7c, respectively. This configuration according to the invention forbids any fluidic communication between the intake and delivery orifices 11, 12, respectively, and the emptying chamber 27 during the intermediate steps also referred to as switchover steps, which are illustrated by FIGS. 7b and 7d.

As illustrated by FIGS. 1 to 3, the cavity 15 is put in fluidic communication with an upstream fluid circuit and a downstream fluid circuit, and with the outside via the intake and delivery orifices 11, 12 opening onto the outer surface of the body 13 and having an axis of symmetry perpendicular to the axis A. Each of the two orifices, namely the intake orifice 11 and the delivery orifice 12, respectively, has a cylindrical part of small diameter opening inside the cylindrical cavity 151 and a portion of larger diameter opening outside of the body 13. In the example illustrated, the large-diameter portion of the delivery orifice 12 thus has a frustoconical form and the small-diameter portion of the intake orifice 11 has cylindrical form. The axis of the intake orifice 11 and the axis of the delivery orifice 12 can be offset longitudinally with respect to the axis A and angularly along a plane perpendicular to the axis A. In the example illustrated in FIGS. 1 and 3, the intake and delivery orifices 11, 12 are offset longitudinally with respect to the axis A and are offset from one another by an angle of 180° along a plane perpendicular to the axis A. In an alternative embodiment (not illustrated), the two orifices, namely the intake orifice 11 and the delivery orifice 12, are angularly offset from one another by an angle of 0°. In another alternative embodiment, they are not longitudinally offset with respect to one another.

As detailed in FIG. 4, the piston 22 has a diameter which is slightly smaller than the diameter of the cylindrical cavity 151, and the sealing between the piston 22 and the body of the fixed part 1 is provided by the compression of the sealing gasket 29 positioned on the end of the piston 22. In particular, the sealing gasket 29 has a generally cylindrical form; the inner surface of said gasket is in close contact with the outer surface of the piston 22, and the outer surface of said gasket is provided with sealing lips 26 intended to be compressed against the surface of the cylindrical cavity 151 in order to ensure a fluid-tightness of the duct and of the chamber.

As illustrated in FIGS. 4 and 5, said sealing lips 26 define multiple channels having different depths, namely at least one first channel having one end opening into the emptying chamber 27, at least one second channel in fluidic connection with said first channel, and additional non-communicating channels which are not in communication with the emptying chamber 27 and preferably having a depth which is less than that of the first channel and of the second channel, in order to minimize the dead volumes. As illustrated in FIG. 4, the first channel opening into the emptying chamber 27 corresponds to the delivery groove 241, the channel in fluidic connection with said first channel corresponds to the intake groove 242, and said first channel and second channel form a duct 24 on the circumference of the gasket.

It should be noted that the duct 24 is entirely arranged on the circumference of the gasket and in particular contains no portion inside the piston 22. As illustrated in FIG. 4 and in FIGS. 7a to 7d, the sealing lips 26 also define additional non-communicating channels having a depth less than that of the delivery and intake grooves and extending around the sealing gasket 29 in order to face one of the orifices, intake orifice 11 or delivery orifice 12 when the other orifice 12, 11 is facing a delivery groove 241 or intake groove 242 of the duct 24 or facing another additional channel.

More particularly, during an operational step of the device illustrated in FIG. 7a, the intake orifice 11 faces the intake groove 242, and the delivery orifice 12 is in one of said additional channels which are not in communication with the emptying chamber 27. In a second operational step illustrated by FIG. 7b, the two orifices, the intake orifice 11 and the delivery orifice 12, are in additional channels which are not in communication with the emptying chamber 27. In a third operational step of the device represented in FIG. 7c, the delivery orifice 12 faces the delivery groove 241, and the intake orifice 11 is in an additional channel which is not in communication with the emptying chamber 27. Advantageously, the width of the delivery groove 241 and of the intake groove is substantially greater than the diameter of the intake and delivery orifices 242. In FIG. 7d, as in 7c, one orifice is covered and the other is in the groove 241.

The duct 24 included on the sealing gasket 29 and delimited by the sealing lips 26 includes a delivery groove 241 forming an angle β between 0° and 70° with the axis A and an intake groove 242, for example, in the form of a helical inner threading forming an angle α with respect to the axis A. The angle β is defined in FIG. 4 and is preferably an angle of 0°, and the angle α is identical to the angle of the slope of the cam 25. In this configuration (illustrated in FIG. 4), the delivery groove 241 is parallel to the axis A and extends in a direction included in the co-linear plane of the cam abutment 28. In an alternative embodiment not represented, the delivery groove 241 and the cam abutment 28 form an angle β with the axis A, which is between 0° and 70° while being different from 0°. Preferably, the delivery groove 241 extends in a direction parallel to that of the extension of the cam abutment 28. In the present case, the spring makes it possible to contribute additional energy to the motor.

In reference to FIG. 5, the position of the free end of the piston 22 in the cavity 151 defines an emptying chamber 27 with cylindrical shape and variable volume. The volume of the emptying chamber 27 is defined by the inner volume of the cavity 151, extending from the closed end of said cavity to the flat circular surface which is part of the free end of the piston 22. When the piston 22 is in its low position, the spring 23 is compressed, the emptying chamber 27 is at its maximum volume (configuration visible in FIGS. 5 and 6), whereas, when the piston 22 is in its high position, the spring is in its released position since it is returned to its initial position with reduced stress, the emptying chamber is at its minimum volume (configuration visible in FIGS. 1 to 4), and the liquid has been expelled.

As detailed in FIGS. 1, 4 and 5, the cam 25 comprises an inclined ramp 251 (FIGS. 4 and 5) which is able to slide on a cam support 14 (FIG. 1), and a cam abutment 28 in the form of a step including a radial surface with respect to the axis A and delimited by two parallel sides 281 and 282 in common with the inclined ramp 251 of the cam 25. In particular, in reference to FIGS. 4 and 5, the side 281 connects the cam abutment 28 to a high portion of the inclined ramp 251, and the side 282 connects the cam abutment 28 to a low portion of the inclined ramp 251. In practice, each side 281, 282 is the edge of a dihedral angle formed by the meeting of the cam abutment 28 with the inclined ramp 251 .

It should be noted that the sealing gasket 29 can be manufactured, for example, by overmolding on the piston 22 or manufactured independently of the piston and assembled thereon. The sealing gasket 29 is positioned around the end of the piston 22 which is able to move in the cavity 151.

As illustrated in FIGS. 7e, 7f, 7g and 7h, the upper portion and the lower portion defining the beginning and the end of the inclined ramp 251 are perpendicular to the axis A. Consequently, the dihedral angle formed by the meeting of the cam abutment 28 with the upper portion or the lower portion of the inclined ramp 251 is a right angle of 90°. The reversal of the direction of rotation of the moving part is prevented by the presence of the cam abutment 28. In an alternative embodiment, not represented, the cam abutment 28 comprises a nonradial surface with respect to the axis of the piston, which connects the upper portion to the lower portion of the inclined ramp 251 with an angle with respect to the axis of the piston different from 90°. In this alternative embodiment, the delivery groove 241 is inclined with respect to the axis of the piston with an angle β between 0° (excluded) and 70°, while being identical to the angle formed by the cam abutment 28 and said axis.

FIGS. 7a to 7d illustrate the development of the lateral surface of the cylinder defined by the sealing gasket 29; the small-diameter portions of the intake and delivery orifices 11 and 12 are represented in a view projected on a plane.

FIGS. 7e to 7h illustrate the development of the outer surface of the cam 25; the cam support 14 is represented in a view projected on a plane. For the sake of simplification and to facilitate understanding of the diagram, a simplified representation of the cam support 14 is shown.

The mode of operation of the device according to the preferred embodiment is as follows:

During the intake step, a motor drives the nearly complete rotation of the cam 25 in order to obtain an oscillatory-rotary movement of the piston 22 in the cavity 15; during the oscillatory- rotary movement, the piston 22 goes from a high position in which the emptying chamber has a minimum volume of liquid (FIGS. 1 to 3) to a low position (FIG. 5) in which the emptying chamber 27 is filled with liquid.

The step defined by the cam abutment 28 can alternately have a position which is adjustable by a pin which is able to transmit kinetic energy to the piston. Between the beginning of the intake step and the end of the delivery step, the cam 25 has performed a complete rotation of 360°.

The pulsating decompression of the axial spring 23 during the delivery step drives the translation of the piston 22 from a low position (FIGS. 5 and 6) in which the emptying chamber 27 is suitable for being filled with liquid to a high position (FIGS. 1 to 4) in which the emptying chamber 27 is suitable for being emptied of liquid.

As illustrated in FIG. 7c, during the delivery step, the intake orifice 11 is covered in an additional channel which is not in communication with the emptying chamber 27, and the delivery orifice 12 is in fluidic communication with a delivery groove 241 which is longitudinal with respect to the axis A or oblique at an angle β between 0° and 70°; in the example illustrated in FIGS. 7a to 7d and in FIGS. 8a to 8d, the angle β is an angle of 0°. FIGS. 8a, 8b, 8g, 8h illustrate examples of configurations in which the intake orifice 11 or the delivery orifice 12 is covered in an additional channel which is not in communication with the emptying chamber. It should be noted that the non-communicating additional channels are exclusively used for providing the sealing and the closing of the intake orifice 11 or the delivery orifice 12 during the intermediate steps, also referred to as minimum and maximum switchover steps.

Reference Numerals

• 1: Fixed part
• 11: Intake orifice
• 12: Delivery orifice
• 13: Body
• 14: Cam support
• 15: Cavity
• 151, 152: Cylindrical cavities
• 16: Spring support
• 18: Shoulder
• 2: Moving part
• 21: Piston driving element
• 22: Piston
• 23: Axial spring
• 24: Duct
• 241 : Delivery groove
• 242: Intake groove
• 25: Cam
• 251: inclined ramp
• 26: Sealing lips
• 27: Emptying chamber
• 28: Cam abutment
• 281, 282: Sides of the cam abutment
• 29: Sealing gasket
• 30: Connection means
• A: Axis of the piston
• D: Device
• α: Tilt angle of the helical intake groove with respect to the longitudinal axis of the piston.
• β: Inclination angle of the delivery groove with respect to the longitudinal axis of the piston.

Claims

1. A device for dispensing product in liquid form, comprising a fixed part and a moving part,

the fixed part including: an intake orifice and a delivery orifice, a body comprising a cavity, into which said orifices open, said cavity being able to partially house the moving part, the volume formed between the surface of the cavity and the moving part defining an emptying chamber,

the moving part able to partially move in the cavity of the fixed part, including: a piston, a piston driving element, an axial spring, a duct extending along the circumference of the piston, such that said duct allows positions that allow fluidic communication between the emptying chamber and just one of said orifices and allows switchover positions in which all fluidic communication between the emptying chamber and each of said orifices is forbidden,

the device including a cam able to convert the rotation of the piston driving element into an oscillatory-rotary movement of the piston,

wherein the axial spring is able to absorb energy during a liquid intake phase and to restore same during a liquid delivery phase, said spring being positioned around the piston which is on the moving part situated in the cavity of the body.

2. The device according to claim 1, wherein the axial spring is a helical spring.

3. The device according to claim 1, wherein the duct is delimited by sealing lips in order to ensure the fluid-tightness between the piston and the body of the device.

4. The device according to claim 1, wherein the duct includes a delivery groove connecting the delivery orifice to the emptying chamber during the delivery phase, and an intake groove connecting the intake orifice to the emptying chamber during the intake phase.

5. The device according to claim 4, wherein the intake groove is in the form of a helical internal threading forming an angle α preferably identical to the angle of the slope of the cam.

6. The device according to claim 4, wherein the delivery groove extends on an axis co-linear with that of the cam abutment and forms with the longitudinal axis of the piston an angle β such that 0° ≤ β ≤ 70°.

7. The device according to claim 6, wherein the angle β is preferably an angle of 0°.

8. The device according to claim 1, wherein the intake orifice and the delivery orifice are angularly separated by an angle between 170° and 190° on a plane perpendicular to the longitudinal axis of the piston.

9. A method for administering a fluid using a device according to claim 1, including the following four successive steps:

a. An intake step, during which the device is actuated to drive the rotation of said cam, in order to obtain an oscillatory-rotary movement of the piston; during said oscillatory-rotary movement, the intake orifice is in communication with the duct and the delivery orifice is covered so as to obtain the filling of an emptying chamber and the compression of the axial spring between the cam and a spring support,

b. A first intermediate step, during which the two orifices, the intake orifice and delivery orifice, are covered and non-communicating, and during which the emptying chamber is at its maximum volume,

c. A delivery step, during which the axial spring is decompressed in order to bring about the translation of the piston, in order to empty the emptying chamber through the first delivery groove in fluidic communication with the delivery orifice,

d. A second intermediate step, during which the two orifices, the intake orifice and the delivery orifice, are covered and non-communicating, the piston is at the end of the stroke in the cavity of the body of the fixed part, and the axial spring is released.

10. The method according to claim 9, wherein the height of the abutment of the cam is adjustable in order to vary the liquid volume ejected from the emptying chamber through the delivery orifice.

11. A medical apparatus containing the device according to claim 1.

12. A fluid cartridge including a fluid circuit and a dispensing device according to claim 1.

13. A method for administering a fluid using a medical apparatus containing the device according to claim 1.