EP3393553A1

EP3393553A1 - Automatic injection device having an improved cam path

Info

Publication number: EP3393553A1
Application number: EP16826372.1A
Authority: EP
Inventors: Kevin Stamp; Pascal Dugand
Original assignee: Nemera la Verpilliere SAS
Current assignee: Nemera la Verpilliere SAS
Priority date: 2015-12-24
Filing date: 2016-12-13
Publication date: 2018-10-31
Also published as: FR3046079A1; BR112018003834A2; US20190001061A1; WO2017109333A1; JP2018538029A; CN108348683A; FR3046079B1

Abstract

The device for injecting a liquid product is intended to receive an injection syringe comprising a syringe body, carrying an injection needle, and a piston mounted axially sliding in the syringe body in the distal direction when an injection is performed. The injection device comprises a piston control member intended to cooperate axially, under the effect of an elastic force, with a piston rod, linked kinematically to the piston in order to make same slide. The injection device further comprises at least one deceleration member, said deceleration member being kinematically linked, in the movement of same in translation along the injection axis X, to the piston control member, the deceleration member being mounted movable in a positioning control member (20) with which it cooperates via a deceleration cam/deceleration cam path (102, 104) contact, one of the deceleration cam and the deceleration cam path (102, 104) being carried by the deceleration member and the other by the positioning control member (20), the deceleration cam path (102, 104) comprising a so-called injection portion (102D, 104D) such that, when the deceleration cam it passes through this injection portion, the piston control member causes the piston to slide, the injection portion (102D, 104D) of the deceleration cam path (102, 104) comprising at least two sections referred to respectively as fast (102R, 104R) and slow (102L, 104L), with different inclinations.

Description

Improved automatic cam injection device

The present invention relates to the field of liquid product injection devices, in particular pharmaceutical, including automatic injection devices.

An automatic injection device is generally a medical device for the automatic administration of a liquid drug requiring injection. These devices allow in particular that people, for example with rheumatoid arthritis, multiple sclerosis, diabetes or undergoing anaphylactic shock in case of allergy, themselves inject their drug dose autonomously.

An example of an automatic injection device is described in US8734402. The device comprises an injection syringe which contains the liquid product to be injected and which is provided with a needle, and a syringe holder. It is usually sufficient to briefly press the device onto the patient's skin to trigger penetration of the needle into the skin, followed by injection of the liquid product, and then retraction of the needle into the device for avoid hurting someone with the needle. More specifically, the injection device is automatic, it comprises an injection spring exerting a pressure on a piston rod via a control member which abuts against the piston rod, thanks to an outline keyed on the proximal end of the piston rod. The piston rod thus moves a piston, which injects the liquid product into the body of the patient. Then once the piston reaches the bottom of the body of the syringe, a relative rotation of the piston rod and the control member releases the polarizing contour, disabling the stop made by the control member against the piston rod , so that the piston rod is free to move back relative to the control member. Simultaneously with this release, a protective spring exerts pressure on the syringe body towards the proximal end of the automatic injection device, so that the injection syringe retracts within the automatic injection device so that that the injection needle is no longer accessible.

A difficulty may arise when the liquid product to be injected is viscous. Indeed, such a product requires time to spread in the skin. Also, when the release of the piston rod at the end of the injection to move it back relative to the control member occurs, it is possible that part of the injected dose comes out of the skin. One possible solution is to provide devices containing doses of liquid to be injected larger than the dose to be injected so that the dose actually remaining in the skin corresponds to the required dose. However this induces a waste of medical liquid and an uncertainty on the amount of liquid actually distributed.

In addition, the injection rate of the product is greater at the beginning of the injection than at the end because the injection spring exerts a greater force at the beginning of the injection, when it is more compressed. An excessive injection rate can be painful for the patient and can in some cases, by shearing molecules of the injected product, degrade this product. Ideally, the injection device should inject the product at a constant rate.

The invention aims to better control the injection rate at least at certain stages of this injection.

For this purpose, the subject of the invention is a device for injecting liquid product, intended to receive an injection syringe comprising a syringe body, carrying an injection needle, and a piston mounted to slide axially in the body of the syringe. syringe in the distal direction when an injection is made, the injection device comprising a piston control member intended to cooperate axially, under the effect of an elastic force, with a piston rod, kinematically connected to the piston for slide it, the injection device further comprising at least one slowing member, this slowing member being kinematically connected in its translational movement along the injection axis X to the piston control member, slowing member being displaceably mounted in a positioning control member with which it co-operates by a slowing cam-retarding cam contact, the retarding cam; ent and the slowing cam path being carried one by the slowing member and the other by the positioning control member, the slowing cam path comprising a so-called injection portion such as when the cam slowing down the injection portion, the piston control member slides the piston, the injection portion of the slowing cam path comprising at least two sections respectively called fast and slow, of different inclinations, so that the axial velocity of the piston controller, when the deceleration cam travels the slow section, is less than the axial velocity of this piston controller when the deceleration cam travels the fast section. Thus, it is possible to choose the forward speed of the piston by choosing appropriate inclinations for each section of the cam paths. The greater the inclination with respect to the injection axis on a section, the more the advance of the piston in the syringe body is slowed when the cam is engaged in this section.

The invention can thus make it possible to slow the flow of product at the beginning and / or at the end of the injection, and thus to improve the quality of the injection.

In the present description, the injection axis corresponds to the axis of the injection device defined by the axis of the injection needle. The injection axis will be called X. Moreover, the distal direction designates the direction farthest from the fingers of a user, that is to say the closest to the skin of a patient at the time of an injection, and the proximal direction designates the opposite direction. In other words, it can be said that the distal direction and the distal direction are the direction and direction that go to the "front" of the injection device. In particular, the distal end of a patch corresponds to the end on the side of the injection needle, and the proximal end is the opposite end. The injection device provided herein is configured to provide automatic product injection, i.e. the movement of the piston to inject the product is controlled automatically, usually by a spring. Possibly, but not necessarily, the injection device is further configured to provide automatic insertion of the injection needle, i.e. the movement of the needle to penetrate the patient's body is also implemented automatically, by a spring. The injection device may further comprise one or more of the following features, taken alone or in combination:

the slowing cam path comprises at least two slow sections,

the two slow sections have different inclinations so that the axial speed of the piston control member, when the retarding cam travels a first slow section, is less than the axial speed of this piston control member when the slowdown cam goes through a slow second section,

the slowing cam path comprises three different inclination sections forming a fast section interposed between first and second slow sections, so that the axial speed of the piston control member is successively slow, fast and slow when the slowdown cam travels the sections slow, fast and slow,

the slow section of the injection part of the slow cam path coincides with a distal end or a proximal end of the injection portion of this slowing cam path, or with each of the distal and proximal ends,

- The slowing cam path comprises at least two different inclination sections so that the angular displacement of the slowing cam traveling therethrough successively in opposite directions of rotation,

the slowing cam is carried by the slowing member and the slowing cam path is carried by the positioning control member;

- the slowing member and the piston control member are merged, - the device comprises a needle control member intended to cooperate axially, under the effect of an elastic force with a syringe holder, kinematically bonded to the syringe body,

the slowing member and the needle control member are combined,

the device comprises two slowing members which are the piston control member and the needle control member.

The invention will be better understood on reading the appended figures, which are provided by way of examples and are in no way limiting, in which:

FIG. 1 is a perspective view of an injection device according to one embodiment of the invention,

FIG. 2 is an exploded perspective view of the injection device of FIG. 1;

FIGS. 3, 4 and 6 are side perspective views respectively of a piston control member, a retaining ring and an outer casing of the injection device of FIG. 1,

FIG. 5 is a sectional perspective view from the distal end of the outer casing of FIG. 6;

FIGS. 7 and 8 are side perspective views respectively of a positioning ring and a piston rod of the injection device of FIG. 1,

FIG. 9 is a cross-sectional view of the syringe holder in which are assembled the injection syringe, the positioning ring and the piston rod of the injection device of FIG. 1;

FIG. 10 is a view in axial section of the proximal end of the syringe holder with the elements that it contains when the injection device is mounted,

FIG. 11 is a perspective side view of a needle control member of the injection device of FIG. 1,

FIG. 12 is a side view of a positioning control member of the injection device of FIG. 1; FIG. 13 is a perspective view, in partial axial section, of several assembled elements of the injection device of FIG. 1;

FIG. 14 is a perspective view of a positioning control member adapted to a second embodiment according to the invention of the injection device.

A liquid product injection device 10, as shown in Figures 1 and 2, allows the automatic administration of a liquid product requiring injection, more particularly a drug. It is intended to receive an injection syringe 12 (visible in particular in Figure 10) containing the liquid product. In the present example, the injection device 10 is configured to provide automatic insertion of the injection needle into the patient's body and automatic injection of the liquid product. As illustrated in FIG. 2, the injection device 10 comprises a certain number of parts, more precisely in this example a syringe holder 14, two protective springs at the front of the injection device 10, a sleeve of FIG. end 16, a protective cap removal member 18, a piston rod 19, a locating ring 50, a positioning control member 20, a needle control member 21, a piston control member 22 , a retaining ring 23, an injection spring 24, and an outer casing 25. As can be seen for example in Figure 10, the injection syringe 12 comprises a syringe body 26 of generally tubular shape around An injection pin X. The syringe body 26 has at its distal end an injection needle 32 (see FIG. 13). The proximal end of the syringe body 26 comprises a collar 38. A piston 40, sliding axially in the syringe body 26, of generally cylindrical shape around the injection axis X, is slidably mounted axially in the syringe body. 26 and allows to inject a liquid product contained in the syringe body 26 by the injection needle 32. The piston 40 has a distal end oriented towards the injection needle 32 and a proximal end 40P in contact with the injection needle 32. piston rod 19. The distal end of the piston rod 19 may in particular be screwed into the piston 40.

In this example, the injection syringe 12 is a pre-filled glass needle syringe with a capacity of 1 ml (milliliter). Note that the syringe body 26 defines a maximum volume of liquid reception, but that it is possible to fill only partially, advancing the piston 40 to the distal end of the syringe body 26. As shown in FIGS. 10 and 13, the syringe holder 14 is generally tubular in shape around the injection axis X, it is open at both ends and is intended to receive the injection syringe 12. The syringe holder 14 is thus a single piece, distinct from two half-shells assembled to one another. The syringe holder 14 is configured to house the injection syringe 12 so that it is fixedly mounted in the syringe holder 14 throughout the operation of the injection device 10. The syringe holder 14 has a distal end disposed on the side of the injection needle 32 and an opposite proximal end 14P. As can be seen in FIG. 10, the syringe holder 14 has, at its proximal end 14P, an internal clearance 44 delimited by an internal shoulder, making it possible to receive the flange 38 of the syringe body 26 when the injection syringe 12 is inserted. in the syringe holder 14. Such internal clearance 44 allows the proximal end 14P to have an inside diameter larger than the rest of the syringe holder 14, and thus to receive, on the one hand, the flange 38, on the other hand The positioning ring 50 of the piston rod 19, these two elements having a greater diameter than the syringe body 26. The proximal end 14P of the syringe support 14 also has an external shoulder 45, arranged axially in the vicinity. internal clearance 44. This outer shoulder 45 forms a blocking relief of the needle control member 21. More specifically, the outer shoulder 45 makes it possible to hook the needle control member 21 on the proximal end 14P of the syringe holder 14 at the time of assembly of a proximal assembly with a distal assembly of the device. injection 10 and until the end of the insertion of the injection needle 32 into the skin of the patient. Thus the control member of the needle 21 is kinematically connected and cooperates axially with the syringe holder 14 until the end of the insertion of the injection needle 32 into the skin of the patient. As can be seen in FIG. 13, the syringe holder 14 allows the attachment of the end sleeve 16 to the injection device 10. The piston rod 19 is kinematically linked to the piston 40 and makes it possible to transmit a pressure on the piston 40 to inject the liquid product. The piston rod 19 comprises a distal end 19D and a proximal end 19P

The piston rod 19 is furthermore configured to be movable between several configurations. The first configuration is a thrust configuration in which the piston rod 19 is able to move the piston 40 in the syringe body 26 under the effect of the injection spring 24 between an initial position and an end position. In the end position, the plunger 40 is at the bottom of the syringe body 26, i.e. towards the distal end of the syringe body 26. The second configuration is a release configuration in which the piston rod 19 is able to retract in the proximal direction of the injection device 10.

The transition from the thrust configuration to the release configuration is effected by a rotation of the piston control member 22 with respect to the piston rod 19. This rotation of the piston control member 22 and the link with the withdrawal of the injection needle 32 will be explained below.

As illustrated in FIG. 8, the piston rod 19 is generally cylindrical in shape around the injection pin X. Two sliding grooves 88 are formed on either side of the piston rod 19. Each sliding groove 88 may, for example, be formed by an axial groove. These sliding grooves 88 extend axially (parallel to the injection axis X) along the piston rod 19 and define a polarizing contour (visible in particular in Figure 9). These sliding grooves 88 are intended to cooperate with a passage opening 92 of the positioning ring 50. The piston rod 19 also comprises a distal abutment 90 of axial retention of the positioning ring 50, more precisely two distal stops 90 diametrically opposite. Preferably, each distal stop 90 is formed by a transverse groove formed in a localized filling of the sliding grooves 88. The proximal end of the piston rod 19 is of generally cylindrical shape around the injection axis X on its distal portion and comprises four radial projections 87, angularly distributed about the injection axis X, intended to cooperate with the piston control member 22.

The positioning ring 50, illustrated in Figure 7, is intended to cooperate with the piston rod 19 to allow both a good axial and angular position of the piston rod 19, and prevent the withdrawal of the piston rod 19 from the operating ring 50, or even from the injection device 10. The axial positioning makes it possible to ensure a correct position with respect to the piston 40 on the one hand and to the piston control member 22 on the other hand . The angular positioning not only prevents the piston rod 19 from rotating on itself during the activation of the piston rod 19 but also provides a predefined angular orientation with respect to the syringe holder 14, allowing abutment axial and then an axial release of the piston rod 19 and the piston control member 22, these configurations being implemented following a rotation of the piston control member 22 by relative to the piston rod 19. The positioning ring 50 is intended to be attached to the proximal end 14P of the syringe holder 14. In order to prevent the free rotation of the positioning ring 50 relative to the syringe holder 14 , the positioning ring 50 comprises angular setting means 98 of the positioning ring 50 on the proximal end 14P of the syringe holder 14. The axial positioning means of the piston rod 19 formed on the positioning ring 50 comprise an axial retaining stop 94 of the piston rod 19, here carried by an elastic tab 96 extending axially from a proximal washer 50P to a distal end 50D of the positioning ring 50. More precisely (see FIG. 11), the positioning ring 50 comprises two diametrically opposite elastic tabs 96, each carrying an axial retaining stop 94, which is formed in this example by a retaining lug axial axial piston rod 19. Each axial retaining stop 94 prevents, by cooperation with the distal stop 90 (visible as in Figure 8) corresponding piston rod 19, that the latter can not be removed entirely (by traction in the proximal direction) of the positioning ring 50 before assembly, and the injection syringe 12 after assembly. The means for axial positioning of the piston rod 19 on the positioning ring 50 are moreover arranged so that, in the storage configuration of the injection device 10, a clearance is present between the distal end 19D of the rod of FIG. piston 19 and the proximal end 14P of the piston 40.

The positioning ring 50 further comprises means for angular positioning of the piston rod 19 on the positioning ring 50, comprising a passage opening 92 (visible in particular in FIGS. 7 and 10) of the piston rod 19 having a complementary polarizer contour of that of the distal end 19D of the piston rod 19. In this way, the passage opening 92 provides a defined and controlled angular positioning of the piston rod 19 relative to the positioning ring 50 all throughout the operation of the injection device 10. In Figure 12, there is shown the positioning control member 20, which comprises two parts, two half-shells intended to be snapped to one another around the syringe holder 14 by latching means 100 comprising various notches and lugs. The positioning control member 20 thus has a generally tubular shape along the injection axis X. The distal end of the positioning control member 20 is provided with means for retaining the end sleeve 16. Once assembled, the end sleeve 16 and the positioning control member 20 are fixed relative to one another throughout the operation of the injection device. 10. As shown in FIG. 12, the positioning control member 20 also includes needle control cam 102 and piston control 104 paths for cooperating respectively with needle control cams 46 and piston controller 106 respectively carried by the needle control member 21 and the piston controller 22 (Fig. 13). Thus, since the needle control member 21 and the piston controller 22 are respectively associated with separate cam paths, once the injection device 10 is activated, the insertion step of the injection needle 32 in the body of the patient and the step of injecting the liquid product contained in the injection syringe 12 are separate and distinct steps, so that they are each implemented in a precise manner, temporally controlled and adapted to the liquid product injected.

According to variants, either or both of the needle control and piston control cam paths are carried respectively by the needle control member and the piston control member, and accordingly, one or both of the needle control cam and piston control cams are carried by the positioning control member.

The needle control cam 102 and piston control 104 paths each comprise two portions, one distal 102D and 104D and the other proximal 102P and 104P. During the injection needle insertion step 32, the needle control 46 and piston control cams 106 are engaged in the proximal portions 102P and 104P of the needle control cam paths 102 and 102. In the liquid product injection step, the needle control 46 and piston control cams 106 are engaged in the distal portions 102D and 104D of the needle control cam paths 102. and the piston control 104. The distal portions 102D and 104D of the needle control cam 102 and piston control 104 paths are referred to as the injection portions 102D and 104D of the cam paths 102 and 104.

In this first embodiment, the control member of the piston 22 is a slowing member 22. As a result, the piston control cam path 104 is a slowing cam path 104 and the piston control cam 106 is a deceleration cam 106.

The injection portion 104D of the deceleration cam path 104 comprises two sections, one proximal, said fast section 104R and the other distal, said slow section 104L. The fast section 104R has an inclination identical to that of the proximal portion 104P of the slow cam path 104. It is therefore not possible, simply by observing the positioning control member 20, to distinguish the boundary between the distal portions 104D and proximal 104P of the deceleration cam path 104. The slow section 104L has an inclination with respect to the injection axis X greater than that of the fast section 104R. The choice of a greater inclination on a section makes it possible to reduce the axial speed of the slowing member 22 when the slowing cam 106 traverses this section. Indeed, a greater rotation of the slowing member 22 is then necessary to travel the same axial distance. This greater rotation causes more friction in different parts of the mechanism and thus limits the speed of the slowing member 22. Thus, the slowing member 22 has a lower axial speed when the slowing cam 106 traverses the slow section 104L as it travels along fast track 104R. This slow axial speed of the slow-down member 22 at the end of the injection allows the product time to diffuse. This ensures that all the pressurized liquid has been injected before the injection needle 32 is removed.

FIG. 12 shows that the proximal portion 102P of the needle control cam path 102 has a greater inclination with respect to the injection axis X than the remainder of the needle control cam path 102. proximal portion 102P is inclined at about 45 °, which allows advanced p ^r ogressive of the injection needle 32, and thus limits the patient's pain. The advancing speed of the injection needle 32 can be adjusted by changing the inclination of the needle control cam path 102. The end of the insertion of the injection needle 32 is done when the needle control member 21 reaches a given angle. At this time, the needle control member 21 disengages from the syringe holder 14, and the injection begins. The proximal portion 102P of the needle control cam path 102 rotates the needle control member 21 to this angular position. The slope and length of this proximal portion 102P of the needle control cam path 102 thus ensure that the injection needle 32 is inserted at the proper depth and velocity into the skin of the patient before the injection does not begin.

According to a variant, it is the needle control member 21 which serves as a slowing member. In this case, the needle control cam path is a slowing cam path having an injection portion comprising a slow section and a fast section, the slow section having an inclination with respect to the axis. injection X greater than that of the fast section so, for example to obtain a slower injection at the beginning of injection and faster end of injection, or vice versa.

The needle control member 21 has a generally tubular shape, as can be seen in FIGS. 11 and 13. The needle control member 21 is movably mounted in the positioning control member 20. A its proximal end, it comprises temporary coupling means 112 with complementary coupling means 114 carried by the piston control member 22 (FIG. 5), so that the needle control member 21 and the organ 22 when the injection spring 24 begins to push the piston control member 22, it also pushes the organ 21, which, being at this stage also coupled to the syringe holder 14, will push the syringe holder 14 in the distal direction, and thus allow the insertion of the injection needle 32 into the skin of the syringe holder 14. patient. More specifically, the temporary coupling means 112 and complementary 114 comprise two complementary parts having a mutual engagement shape, for example two axially extending inverted hooks, the first carried by the proximal end of the control member of needle 21 and the second carried by the distal end of the piston control member 22. Furthermore, the needle control member 21 comprises a locking pin 107 (barely visible in Figure 13) protruding of its inner surface and having a funnel-shaped shape, the fine part of the funnel being oriented on the distal side. The locking pin 107 is intended to cooperate with the outer shoulder 45 of the proximal end 14P of the syringe holder 14. In fact, this outer shoulder 45 forms a locking relief of the needle control member 21 at the beginning. operation of the injection device 10, during the insertion of the injection needle 32 into the skin of the patient. As mentioned above, the outer shoulder 45 thus makes it possible to hook the needle control member 21 on the proximal end 14P of the syringe holder 14 at the time of assembly of the proximal assembly with the assembly. distal of the injection device 10. This assembly takes place by axial insertion of the locking pin 107 in a guide rail (not shown) of the syringe holder 14, then by rotation of the needle control member 21 relative to to the syringe holder 14 so that, when the injection device 10 is in the storage position before being used, the outer shoulder 45 is stuck axially (along the injection axis X) between the pin of locking the distal side 107, and the distal end of a guide rib (not shown) on the proximal side. The needle control member 21 further comprises, on its outer surface and on its distal end 21 D, the needle control cam 46 (see FIG. 13) intended to cooperate with the control cam path of FIG. needle 102 (see FIG. 12) formed in the positioning control member 20.

The piston control member 22, visible in particular in Figures 3 and 13 has a generally tubular shape. It is mounted displaceable in the positioning control member 20. It is configured to apply a force on the piston 40 (via the piston rod 19), under the action of the injection spring 24 (visible in Figure 2). This force allows the axial displacement (along the axis of injection X) of the piston 40 in the distal direction of the injection device 10, to inject the liquid product into the skin of the patient.

The piston control member 22 carries a stop 118 which can be retracted between an active configuration for retaining the injection spring 24 in the compressed state and a retracted configuration for releasing the injection spring 24. More specifically, the organ Piston control 22 comprises two diametrically opposed semi-flexible semi-annular elastic tabs 116, each carrying a retractable stop 118 intended to cooperate with the locking member of the outer casing 25. Each of the semi-annular elastic tabs 116 carrying the stops retractable 118 extends axially (along the axis of injection X) towards the proximal end of the injection device 10, each semi-annular elastic tab 116 thus being deformable between a radially spaced rest configuration giving the retractable stop 118 its active configuration and a radially retracted configuration giving the retractable stop 118 its retracted configuration.

The outer casing 25 comprises a locking member 122 of the retractable abutment 118 in its active configuration, provided in the proximal end of an outer casing 25 of the injection device 10. This locking member 122 provided at the proximal end 25P of the outer casing 25 comprises a radial surface, recessed (in two distinct orifices, facing each other) in the vicinity of an unlocking pin 124 so as to be traversed by the semi-annular elastic tabs 116 of the control member of piston 22 carrying the retractable stops 118 at least when the locking member 122 is in the locking position. The locking pin 122 comprises two sections of different diameters causing the passage of the retractable stops retracted configuration by a support of the distal end of the injection device 10 on the skin of a patient. As can be seen in FIGS. 3 and 13, the piston control member 22 has, at its distal end, a generally cylindrical shape carrying the complementary coupling means 114 and the piston control cam 106, and delimiting a 115, the outer shoulder, forming a seat for the injection spring 24. The piston control member 22 also comprises a distal shoulder 117, the distal shoulder 117 is interrupted by notches, extending towards the proximal end of the piston control member 22 so as to form axial slots 119 (visible in Figure 3). The piston control cam 106 carried by the piston control member 22 is intended to cooperate with the piston control cam path 104 (visible in FIG. 12) provided in the positioning control member 20 to regulate the displacement of the elements of the injection device 10 under the effect of the injection spring 24 (see Figure 2). The rotation of the piston controller 22 is induced by the axial displacement of the piston control cam 106 in the piston control cam path 104.

As mentioned above, the piston rod 19 comprises a generally cylindrical portion provided with at least one radial projection 87, configured to cooperate with the piston control member 22 activated by the injection spring 24.

The relative angular displacement of the piston control member 22 relative to the piston rod 19 is during the advancement thereof in the syringe body 26, that is during the injection of the liquid product. . The relative angular displacement of the piston control member 22 (relative to the piston rod 19) is at a predetermined angle, for example close to 45 °.

The second part of the angular displacement considered is preferably greater than 1 °, for example close to 2 °. This second patient of the movement of the piston control member 22 around the piston rod 19 essentially comprises an angular component. Indeed, the slow section 104L of the distal portion 104D of the piston control cam path 104 takes into account the rotation that remains before alignment of the radial projections 87 with the axial slots 119 while the piston rod 19 has stopped s In the piston rod release configuration 19, the piston control member 22 no longer abuts against the radial projections 87 of the piston rod 19 and releases a passage for the piston rod 19. that the piston rod 19 can retract in the proximal direction. The retaining ring 23 serves to retain the injection spring 24 in the compressed state (see FIGS. 2 and 4). More precisely before the injection, the injection spring 24 is maintained in its compressed state by means of the retractable stop 118 carried by the piston control member 22, cooperating with a complementary surface carried by the retaining ring 23 ( see Figure 13). This retaining ring 23 is attached to the proximal end 20P of the positioning control member 20. For this purpose, it has two lugs 121, external and diametrically opposite, for wedging the retaining ring 23 intended to cooperate with complementary notches of the positioning control member 20. The distal end of the retaining ring 23 further forms a proximal seat for the injection spring 24, and the proximal end forms a complementary abutment surface for the retractable stop 118.

The abutment 118 is retractable between an active configuration for retaining the injection spring 24 in the compressed state, corresponding to a radially protruding position for retaining the injection spring 24 and a retracted configuration for releasing the injection spring 24 enabling his relaxation. Thus, the retractable stop 118 in active configuration abuts against a complementary surface carried by a retaining ring 23 of the injection spring 24. This retaining ring 23 is attached to the proximal end of the positioning control member 20.

The injection spring 24 is the main engine of the injection. Also, it must have sufficient force to be able, on the one hand, to penetrate the injection needle 32 in the body of the patient, and on the other hand, to move the piston 40 in the syringe body 26 to inject the liquid product. Its strength is preferably greater than 20 Newton or 50 Newton or 80 Newton for a relatively viscous liquid product or for a syringe / needle section high ratio. This injection spring 24 is deformable between a compressed state before use of the injection device 10 and a relaxed state after injection of the liquid product contained in the syringe body 26. The outer casing 25 (see FIGS. 1 and 2) is the In this example, this part envelopes most parts of the injection device 10. In particular, it allows these parts to be isolated from the outside.

The main operating steps of the injection device 10 are described below.

As can be seen in FIG. 1, the injection device 10 presents itself the user in the form of a tube about ten centimeters long. Only the outer casing 25 and the removal member 18, or the end sleeve 16 if the removal member 18 is removed, are visible and accessible to the user. Before the use of the injection device 10, the injection needle 32 is protected by a cap not shown in the figures. This cap is removed by means of the withdrawal member 18 illustrated in FIG. A first operating step consists of holding the withdrawal member 18 with one hand and the outer casing 25 with the other hand and pulling on the withdrawal member 18 along the injection axis X in a distal direction in order to strip the injection needle 32. The injection needle 32 remains inaccessible because, as illustrated in FIG. 5, it is wrapped around the end sleeve 16.

Once the removal member 18 is removed from the injection device 10, the end sleeve 16 in the form of the distal end and the injection device 10 is ready for use. At this point, the injection needle 32 is set back in the end sleeve 16, for example 3 mm (millimeters), to avoid accidental puncture.

In a next step, the distal end of the end sleeve 16 is placed against the patient's skin, where the injection of the medical liquid contained in the injection syringe 12 is desired.

This step is followed by an unlocking step, during which a slight axial pressure is applied in the distal direction on the outer casing 25. This support of the distal end of the injection device 10 on the patient's skin triggers an axial displacement of the outer casing 25 towards the end sleeve 16. In other words, the end sleeve 16 slides slightly inside the outer casing 25 towards its proximal end, generating a sliding, to the inside the outer casing 25 and towards the proximal end of the outer casing 25, the positioning control member 20 and the retaining ring 23. This sliding results in the unlocking of the retractable abutment 118 carried by the proximal end. of the piston control member 22.

The unlocking step is followed by a step of triggering the automatic injection, during which the user continues the axial pressure on the outer casing 25 by pressing on the skin of the patient, in the continuity of the axial pressure started. during the unlocking step. This additional pressure generates a compression of the protective springs (not shown) which allows, first of all, a axial approach (along the injection axis X) of the end sleeve 16 and the syringe holder 14. Thus, the end sleeve 16 slides further inside the outer casing 25 towards its proximal end, generating a additional sliding, inside the outer housing 25 and towards the proximal end of the outer housing 25, the positioning control member 20 and the piston control member 22. As a result, the retractable stop 118 carried by the piston control member 22 slides towards the proximal end of the outer casing 25, which generates its retraction out of the engagement of the retaining ring 23, by ramping effect between the retractable stop 118 and the proximal surface of the outer casing 25, so that the injection spring 24 is released.

The release of the injection spring 24 triggers a series of cascading reactions which result in the penetration of the injection needle 32 into the patient's body and the injection of the liquid product contained in the syringe body 26. It will be noted that that the stroke of the injection needle 32, during these operations, is 9 mm, so that the injection needle 32 exceeds about 6 mm, corresponding to the depth of injection into the skin of the patient. In particular, the injection spring 24 thrusts in the distal direction on the piston control member 22 which is, at this stage, coupled with the needle control member 21 due to the entanglement of the means of The displacement of the needle control member 21, being integral with the syringe holder 14 via the outer shoulder 45, generates the displacement in the distal direction of the syringe holder 14. As the injection syringe 12 is mounted integral with the syringe holder 14, the injection syringe 12 is also pushed towards the distal end of the injection device 10 and the injection needle 32 springs out of the end sleeve 16. This axial approximation of the end sleeve 16 and the syringe holder 14 is by sliding of the syringe holder 14 into the end sleeve 16. Once the injection needle 12 is inserted into the skin of the patient, the injection can co mmencer. Note that simultaneously with the penetration of the injection needle 32, the needle control cam 46 of the needle control member 21 is guided by the corresponding needle control cam path 102. positioning control member 20, more precisely by the portion inclined at 45 ° of the needle control cam path 102. It results from this inclination at 45 ° braking of the trigger and injection spring 24, if although the rate of penetration of the injection needle 32 into the skin of the patient is lower than the uninhibited rate of expansion of the injection spring 24, so that the pain associated with the penetration of the injection needle Injection 12 is advantageously reduced. Simultaneously with the axial displacement of the needle control member 21, a rotation of the piston control member 22 with respect to the positioning control member 20 is generated about the injection axis X, because of the piston control cam 106 which cooperates with the inclined piston control cam path 104. This rotation results in a decoupling of the needle control member 21 and the piston control member 22, as well as a coupling of the piston control member 22 and the piston rod 19, achieved by an abutment of the control member of the piston 22 with the piston rod 19, more precisely with the radial projections 87 of the piston rod 19 (see Figure 9). The thrust exerted by the injection spring 24 on the piston control member 22 results in a thrust on the piston rod 19, thus on the piston 40 in the syringe body 26, involving an injection of the liquid product into the body of the patient.

It is understood that the relative axial advance of the needle control member 21 and the piston control member 22 is controlled by the cooperation of the needle control cams 46 and the piston control cams 106 with the paths. corresponding needle control cams 102 and piston control cams 104 of the positioning control member 20. Thus, the cooperation between the needle control cams 46, the piston control means 106, the control members Needle 21 and piston control 22 with the corresponding needle control cam 102 and piston control cam paths of the positioning control member 20 independently control the penetration of the injection needle. 32 in the skin of the patient and the injection of the medical liquid contained in the syringe body 26. It will be noted that the mechanism of successive couplings, comprising a coupling at first the injection needle control members 2 1 and piston 22, and a second coupling of the piston control member 22 and the piston rod 19 makes the penetration of the injection needle 32 and the injection completely independent. that is, it is necessary to reach the proper injection needle depth 32 before starting the injection, which avoids incorrect injection.

Once the injection is complete, the piston control member 22 completes its rotation about the piston rod 19 and the piston rod 19 is in the release configuration. The injection spring 24 is expanded and the two protective springs (not shown) can freely relax: in fact they are no longer subjected to the force exerted by the injection spring 24 and thus generate a protective position in which the syringe holder 14 is axially remote from the end sleeve 16. This axial distance results in the retraction of the injection needle 32 in the end sleeve 16, thus avoiding any risk of injury. Thus, at the end of the injection, the syringe holder 14 rises freely in the piston control member 22. Due to the rotation of the latter which has allowed to align the radial projections 87 of the piston rod 19 with the axial slots 119, a passage has been released so that the piston rod 19 can retract relative to the piston control member 22, in the proximal direction and not interfere with the retraction of the driven syringe body 26 by the syringe holder 14. The syringe holder 14 is thus axially remote from the end sleeve 16, and the injection needle 32 is retracted into the end sleeve 16, thus avoiding any risk of injury. Since the piston rod 19 and the piston control member 22 are disengaged (because the axial slots 119 cooperate with the radial projections 87), the syringe body 26, driven by the syringe holder 14, rises back into the device. injection 10 and drives the injection needle 32 in its movement. The injection needle 32 is thus retracted.

With reference to FIG. 14, a positioning control device 20 adapted to a second embodiment according to the invention of the injection device will be described below. In this figure 14 elements similar to the elements of the preceding figures are designated by identical references.

In this embodiment, the needle control member 21 and the piston controller 22 are both slowing members (21, 22). The needle control cam 102 and piston control cam 104 are thus slowing cam paths and the piston control needle control cams 46 and 106 are slowing cams.

In this embodiment, the distal portions 102D and 104D, or injection portions, of the two slowing cam paths 102 and 104 comprise a section, said fast section 102R and 104R, interposed between first and second sections, said sections slow 102L and 104L. The rapid sections 102R and 104R and the first and second slow sections 102L and 104L have different inclinations with respect to the axis of injection X so that the axial speed of the needle control members 21 and the piston 22 is lower when their deceleration cams 46 and 106 traverse the slow sections 102L and 104L than when they traverse the 102R and 104R fast sections. Choosing a larger inclination for a section reduces the axial speed of the needle control members 21 and piston 22 when the slowing cam 46 or 106 runs through this section. Indeed, a greater rotation of one of the slowing members 21 or 22 is then necessary to travel the same axial distance. This greater rotation causes more friction in different parts of the mechanism and thus limits the speed of the needle control members 21 and piston 22.

The slowing cam paths 102 and 104 have sections 102R and 102L or 104R and 104L inclined relative to the injection axis X in opposite directions. These changes in direction of inclination allow to use shorter lengths on some sections, including slow 102L and 104L, without the angle traveled is too important and triggers the decoupling of the body of syringe 26 and the organ 21 or the decoupling of the piston rod 19 and the piston control member 22.

The two slowest segments 102L and 104L the most distal of the deceleration cam paths 102 and 104 coincide with the distal ends of the distal portions 102D and 104D of these slow cam paths 102 and 104. These two sections thus impose a strong slowdown of the end of the injection. During this slowdown, the injection rate is almost zero. Thus the injected product has time to diffuse before the withdrawal of the injection needle 32 which takes place when the injection cam 106 reaches the distal end of the piston control cam path 104.

The two most proximal slow sections 102L and 104L of the deceleration cam paths 102 and 104 coincide with the proximal ends of the distal portions 102D and 104D of these deceleration cam paths 102 and 104. These two sections thus impose a slow velocity in injection start. This slow speed makes it possible to make the flow rate during the injection more constant by preventing the flow rate from being greater at the beginning of the injection because of the greater compression of the injection spring 24.

It can thus be seen that the needle control cam path 102 has four distinct sections, three sections 102L and 102R are located on the distal portion 102D of the needle control cam path 102 while the fourth is located on its part. proximal 102P. Note that the section carried by the proximal portion 102P has an inclination relative to the injection axis X greater than that of the fast section 102R. This inclination is chosen so that the axial speed of the organs the needle control cam 46 of the needle control member 21 traverses the proximal portion 102P of the needle control cam path 102 when the needle control 21 and piston 22 are lower than when needle control cam 46 traverses the fast section 102R.

It is also seen that the piston control cam path 104 has four distinct sections, three sections 104L and 104R are located on the distal portion 104D of the piston control cam path 104 while the fourth is located on its proximal portion 104P. . Note that the section carried by the proximal portion 104P has an inclination close to that of the fast section 104R.

Thus, during the injection phase, the piston control cam 106 will progressively traverse the slow sections 104L, fast 104R and slow 104L, leading to a successively slow injection speed, then fast and then slow again.

In a variant, the different fast and slow sections are not carried by the two slowing cam paths 102 and 104, for example only one of the two needle control cam paths 102 or the piston control 104 of the member positioning control 20 comprises sections whose inclinations are different.

According to another alternative or combined variant, two slow sections 102L or 104L carried by the same slow-down cam path 102 or 104 may have different inclinations.

According to yet another alternative or combined variant, the piston control and needle control cam paths meet to form a single cam path. The main steps of assembly of the injection device 10 are now described.

Overall, the assembly of the injection device 10 comprises four main steps:

a step of assembling a distal subassembly comprising the syringe support 14,

a step of insertion of the injection syringe 12 into the syringe holder 14 from its proximal end 14P, a step of insertion of the preassembled positioning ring 50 with the piston rod 19 on the proximal end 14P of the syringe support 14, preferably being positioned relative to one another axially by means of axial positioning 94,

a step of assembling a proximal subassembly, attached over the piston rod 19, with the distal subassembly.

We first assemble a first subset, called distal subset. A first step for this comprises the interlocking of the end sleeve 16 with the withdrawal member 18. The step is followed by a step of snap-fitting the syringe holder 14 with the end sleeve 16, by the through the interlocking of radial projections 52 of the syringe holder 14 in proximal windows 80 of the end sleeve 16. The protective springs are threaded onto guide rods of the syringe holder 14 and the end sleeve 16 and held in place by snapping the two pieces together.

Moreover, we assemble a second subset, called proximal subset. For this purpose, the positioning control member 20, the needle control member 21, the piston control member 22, the retaining ring 23, the injection spring 24 and the outer casing 25 are assembled. More precisely, the injection spring 24 is first assembled on the proximal end of the piston control member 22. These elements are then placed in one of the two half-shells of the piston member. positioning control 20, by additionally adding the needle control member 21 in the coupling position with the piston control member 22. The second half-shell of the positioning control member 20 is then secured. on the first half-shell, then the outer casing 25 is threaded around these elements, terminating the assembly by snapping the distal end of the outer casing 25 and that of the positioning control member. 20, this snapping nevertheless leaving the possibility of a axial sliding, allowing the positioning control member 20 to move back relative to the outer casing 25.

In addition, a third subset is assembled, called an intermediate subset. This intermediate subassembly comprises the piston rod 19 provided with the positioning ring 50.

The injection syringe 12, provided with its protective cap 42 and the piston 40, also forms another element apart. The injection device 10 is assembled by inserting, in the distal subassembly, the injection syringe 12, by inserting the latter into the syringe holder 14 from its proximal end. Once the injection syringe 12 and the distal subassembly have been assembled, the intermediate subassembly is brought back into the proximal end of the syringe body 26, by cooperation of the positioning ring 50 with the syringe holder 14. Then, relates the proximal subassembly over the piston rod 19, in particular inserting the locking pin 107 of the needle control member 21 within a guide rail provided in the syringe holder 14, and the whole is locked by rotation of the withdrawal member 18 relative to the outer casing 25, generating in particular a rotation of the locking pin 107 so that the outer shoulder of the syringe holder 14 is blocked between the locking pin 107 and a guide rib. It is understood that this assembly is particularly easy to implement, without requiring complex tools.

The invention is not limited to the embodiments presented and other embodiments will become apparent to those skilled in the art. Among the multiple possible variants, it will be noted that it would be possible in particular to bring the piston rod to the piston by screwing. In this case, the positioning ring is assembled while being in the retracted position on the piston rod, then the piston rod is screwed on and the positioning ring is then slid to wedge it on the syringe support and activate. the axial positioning means.

Furthermore, it will be appreciated that although an injection device 10 is described configured to provide both automatic insertion of the injection needle 32 into the patient's body and automatic injection of the liquid product once the inserted needle, it is possible to provide a slowing device as described above on an injection device ensuring only an automatic injection of the product and whose injection needle is configured to be manually inserted into the body of the patient.

Claims

1. A liquid product injection device (10) for receiving an injection syringe (12) comprising a syringe body (26) carrying an injection needle (32) and a piston (40) axially slidably mounted in the syringe body (26) in the distal direction when an injection is made, the injection device (10) comprising a piston control member (22) for axially cooperating under the effect of a force elastic, with a piston rod (19), kinematically connected to the piston (40) for sliding, characterized in that the injection device (10) further comprises at least one retarding member (21, 22), this slowing member (21, 22) being kinematically connected in its translational movement along the injection axis X to the piston control member (22), the slowing member (21, 22) being displaceably mounted in a positioning control member (20) with which it cooperates by a cam contact of slowing down (46, 106) slowing cam path (102, 104), the slowing cam (46, 106) and the slowing cam path (102, 104) being carried by the slowing down (21, 22) and the other by the positioning control member (20), the slowing cam path (102, 104) comprising a so-called injection portion (102D, 104D) such as when the cam of slowing through this injection portion, the piston controller (22) slides the piston (40), the injection portion (102D, 104D) of the slowing cam path (102, 104) having at least one least two sections respectively called fast (102R, 104R) and slow (102L, 104L), of different inclinations, so that the axial speed of the piston control member (22), when the retarding cam (46, 106) traverses the slow section (102L, 104L), which is less than the axial speed of this piston controller (22) when the speed cam (46, 106) traverses the fast section (102R, 104R), in that the deceleration cam (46, 106) is carried by the deceleration member (21, 22) and the deceleration cam path (102). , 104) is carried by the positioning control member (20), and in that the liquid product injection device (10) comprises two slowing members (21, 22) which are the control member of the piston (22) and the needle control member (21).

2. Injection device (10) according to the preceding claim, wherein the slowing cam path (104) comprises at least two slow sections (104L).

Injection device (10) according to claim 2, wherein the two slow sections (102L, 104L) have different inclinations so that the axial speed of the piston control member (22), when the retarding cam (46, 106) traverses a first slow section (102L, 104L), is less than the axial speed of said piston controller (22) when the slowing cam (46, 106) traverses a second slow section (102L, 104L).

4. Injection device (10) according to any one of the preceding claims, wherein the slowing cam path (102, 106) comprises three sections of different inclinations forming a fast section (102R, 104R) interposed between first and second slow sections (102L, 104L) so that the axial velocity of the piston control member (22) is successively slow, fast and slow as the deceleration cam (106) traverses the slow sections (104L) , fast (104R) and slow.

Injection device (10) according to any one of the preceding claims, wherein the slow section (102L, 104L) of the injection portion (102D, 104D) of the deceleration cam path (102, 104). coincides with a distal end or a proximal end of the injection portion (102D, 104D) of this slowing cam path (102, 104), or with each of the distal and proximal ends.

Injection device (10) according to any one of the preceding claims, wherein the slowing cam path (102, 104) comprises at least two different inclination sections so that the angular displacement of the cam of slowing down (106) running through them evolves successively in opposite directions of rotation.

7. Injection device (10) according to any one of the preceding claims, wherein the slowing member (21, 22) and the piston control member (22) are merged.

Injection device (10) according to any one of the preceding claims, comprising a needle control member (21) for axially cooperating under the effect of an elastic force with a syringe holder (14). ), kinematically connected to the syringe body (26).

9. Injection device (10) according to claim 8, wherein the slowing member (21, 22) and the needle control member (21) are merged.