ES2894827T3 - Automatic injection device with timing means - Google Patents

Abstract

Device (1) for automatic injection of a product at an injection site, the injection device (1) comprising: a receptacle (5) having an open proximal end and a substantially closed distal end and which is intended to receive the product, and provided at its distal end with an injection needle (6) that provides an exit opening for the receptacle (5), a housing (9) intended to receive, at least partially, the receptacle (5), being able to move the receptacle (5) in relation to the housing (9) between an initial position, in which the needle (6) is contained within the housing (9), an insertion position, distally separated in relation to the initial position and in in which the needle (6) is exposed along a predetermined length, and a final position in which the needle (6) is contained within the housing (9), a piston (7), provided in the receptacle (5 ) and that can move with respect to the receptacle or (5), timing means in the form of a plunger rod (40) having a proximal portion (41) and a distal portion (42), the plunger rod (40) being coupled to the piston (7) for causing the piston (7) to move with respect to the receptacle (5), the movement of the piston (7) causing the product to be expelled from the receptacle (5) through the injection needle (6), return means elastics (25) coupled to the housing (9) to move the receptacle (5) from the insertion position to the final position, and automatic injection means (24), arranged to automatically cause the piston rod (40) to push distally to the piston (7), characterized in that the device (1) further comprises retaining means, formed at least partially in the housing (9) and arranged to maintain the receptacle (5) in the insertion position, and some deactivation means, formed in the proximal part of the plunger rod (40) and arranged These to automatically release the retaining means and cause the receptacle (5) to move to the final position, happening that, when the piston (7) comes into contact with the distal end of the receptacle (5), under the force exerted by the automatic injection means (24) into the proximal portion of the plunger rod (40), the distal portion of the plunger rod (40) is thereby stopped and the proximal portion of the plunger is allowed to continue its distal movement under pressure. force exerted by the automatic injection means (24) for a given time until the deactivation means cooperate with the retaining means to cause the receptacle (5) to move from the insertion position to the final position.

Description

DESCRIPTION

Automatic injection device with timing means

The present invention refers to a device for the automatic injection of a product in a very safe way, especially for self-injection.

In this application, the distal end of a component or device is to be understood as the end farthest from the user's hand and the proximal end is to be understood as the end closest to the user's hand. Also, in this application, the "distal direction" should be understood as the direction of injection, and the "proximal direction" should be understood as the direction opposite to the direction of injection.

Some diseases need regular injections of drugs or products, for example daily. To simplify treatment, some auto-injectors have been provided to allow the patient to inject himself.

Naturally, since the patient is usually neither a nurse nor a person trained in medical devices, such autoinjectors should prove to be very easy to use and also very safe. In particular, the needle must be inserted to the correct depth, the correct dose of product must be injected, that is, a complete injection must be made, and the injector must be deactivated after use before being discarded. Preferably, the needle should not be exposed, before and after use, in order to prevent any accidental needlestick injury.

For these reasons, most autoinjectors feature a high degree of automation. Usually, the user only has to apply the device to the injection site and then press a button, for example, in order to activate the insertion of the needle and the automatic injection of the product. In some devices, in particular when the injection is automatic, some damping means are provided in order to control the speed of injection and thereby limit a possible unpleasant feeling for the patient.

Documents EP 1586 341 and EP 1586 342 disclose injection devices provided with damping means to control the speed of injection. Documents WO2005115512 and US2005273055 disclose injection devices. Documents WO03097133 and US2004024367 disclose injection devices with automatic needle retraction. US2001005781 discloses an autoinjector for replaceable syringe-type receptacles.

As for the protection of the needle after use, some devices are provided with a sleeve that extends the length of the needle once the user has removed the device from the injection site. Alternatively, the needle may automatically retract into the device at the end of the injection without further action by the user. Therefore, when the user removes the device from the injection site, the needle is already retracted within the device and the user is not at risk of injury.

However, one of the problems with needle retraction-based autoinjectors is ensuring that all of the product has been injected before the needle retracts. Actually, in most of these devices, due to the dimensional tolerances of the assembled parts of the device, it is necessary to activate the retraction of the needle just before the end of the complete injection, thereby creating a dead volume at the bottom. of the syringe body. The result is that the dose of product is not fully injected, which can result in improper dosing for the patient or user.

Accordingly, there is a need for self-injection devices that allow the needle to be retracted into the device at the end of an automatically actuated injection, with the assurance that all of the product has been injected prior to needle retraction.

The present invention satisfies this need by proposing a device for the automatic injection of a product at an injection site, said device allowing both the retraction of the needle at the end of an automatically actuated injection and the complete injection of the product.

The present invention refers to a device according to claim 1.

The device of the invention allows the needle guard to be removed prior to use of the device with limited or no rotation of the needle guard. Consequently, possible rotation of the needle tip within the rubber forming the needle guard is prevented, and also erosion of the central portion which could result from such potential rotation is prevented. Thus, the integrity and sterility of the needle are preserved and product administration can be safely completed.

The device of the invention allows the injection of the entire product before the needle retracts. Thanks to the timing means of the device of the invention, the retraction of the needle is not activated when some product is still present in the bottom of the injection device receptacle. Some time, for example 1 to 10 seconds, is allowed before needle retraction is activated.

Therefore, the device of the invention is very safe and very simple to use. The user need only apply the device to the injection site and then activate the first deactivation means to start operation. At the end of the full injection, and only when all the product is injected, the needle retracts into the device and the user can remove the device from the injection site without any risk.

In an embodiment of the invention, said housing is coupled to a protector extraction element comprising a cover to which said needle protector is fixed, said housing comprising grooves to guide the translation of said cover when said cover is closed. removed together with the removal of said protector removing member in view of using said device.

In an embodiment of the invention, said timing means comprise a chamber comprising a ventilation outlet, said chamber being hermetically sealed by a sealing cover in an initial state, and defining an initial volume of said chamber and in which a predetermined amount of fluid is contained within said initial volume, said sealing cover within said chamber being movable from said initial state to a final state in which at least part of said fluid has escaped through said vent .

Said ventilation outlet can be a simple hole, with a small diameter. For example, said diameter may range from 15 microns to 25 microns. Alternatively, said ventilation outlet can be an exhaust valve comprising a membrane that allows the passage of fluid. Said membrane may be composed of a material selected from the group comprising polytetrafluoroethylene, polyethylene, paper, fabric, foam, porous plastic, and combinations thereof. The diameter of said membrane can be about 1 mm.

Said fluid may be a gas, such as air. Preferably, said fluid is under pressure. Alternatively, said fluid may be a viscous liquid, such as oil or grease.

Preferably, said device further comprises elastic return means coupled to said chamber for moving said sealing cover from said initial state to said final state, said deactivation means being coupled to said chamber, such that said deactivation means release said means. retention only when said sealing cover is in said final state.

In an embodiment of the invention, said chamber comprises the proximal portion of a sleeve having a closed proximal end and an open distal end, said closed proximal end comprising a vent outlet and said open distal end comprising an outer radial rim, said device further comprising a piston provided in said receptacle and movable relative to said receptacle, and a plunger rod coupled to said piston for causing said piston to move relative to said receptacle, movement of said piston causing said product is expelled from said receptacle through said injection needle,

- said sealing cover closing, in its initial state, the inner proximal space of said sleeve, thereby defining said chamber, said sealing cover being coupled to said plunger rod,

- said outer radial rim being able to cooperate with said second retaining means and release them when said sealing cover comes into contact with said closed proximal end of said sleeve.

Advantageously, said device further comprises first elastic return means coupled to said housing to move said receptacle from said initial position to said insertion position, second elastic return means being coupled to said housing to move said receptacle from said insertion position to said final position, and a ring, said ring being coupled to said receptacle at least from said insertion position to said final position of said receptacle,

- said retaining means comprising a flexible tongue provided in said housing and engaged on a stop surface located on said ring, when said receptacle is in said insertion position,

- said outer radial rim deflecting said flexible tab and thereby disengaging said tab from said ring, when said sealing cover contacts said closed proximal end of said sleeve, thereby releasing said second resilient return means and causing said receptacle is moved to said final position.

Preferably, the device of the invention further comprises first retaining means, arranged to maintain said receptacle in said initial position, and first deactivation means, arranged to release said first retaining means and cause the insertion of said needle into the injection site, said first retaining means comprising a flexible tooth provided in said housing said flexible tooth engaging said outer radial rim of said sleeve when said receptacle is in said initial position,

- said first deactivation means comprising a push button comprising at least one distal leg,

- said distal leg cooperating with at least said flexible tooth to deflect and disengage said flexible tooth from said outer radial rim, under the effect of manual pressure exerted on said push button, thereby releasing said first elastic return means and causing said receptacle moving from said initial position to said insertion position.

In another embodiment of the invention, said sleeve forms said first deactivation means, said first retaining means comprising an external projection provided on said sleeve, said external projection abutting against a stop element provided on said housing and preventing translation distal of said sleeve when said receptacle is in said initial position, said stop element being surmountable by said outer projection under manual pressure exerted on said sleeve, thereby releasing said first elastic return means and causing said receptacle to move from said initial position to said insertion position.

In a further embodiment of the invention, said device further comprises a piston provided in said receptacle and movable relative to said receptacle, a plunger rod coupled to said piston for causing said piston to move relative to said receptacle the movement of said piston causing said product to be expelled from said receptacle through said injection needle, second elastic return means coupled to said housing for moving said receptacle from said insertion position to said final position, and means self-injecting, arranged to automatically cause said plunger rod to push said piston distally,

- said deactivation means being formed in the proximal part of said plunger rod and said retaining means being partially formed in said housing,

- said plunger rod being provided in two parts, a proximal part and a distal part, when said piston comes into contact with the distal end of said receptacle, under the force exerted by said automatic injection means on the proximal part of said rod said distal portion of said plunger rod thereby being stopped and said proximal portion of said plunger being allowed to continue its distal movement under the force exerted by said automatic injection means for a predetermined time until said deactivation means cooperates with said retaining means for causing said receptacle to move from said insertion position to said end position, said proximal portion of said plunger rod forming part of said timing means.

Advantageously, said device further comprises a ring, said ring being coupled to said receptacle when said receptacle moves from said insertion position to said final position,

- said retaining means comprising a radially flexible tab located on the inner wall of said housing, engaged on a stop surface of said ring, when said receptacle is in said insertion position,

- said deactivating means comprising a head of said proximal portion of said plunger rod, said plunger rod head deflecting said radially flexible leg under the force exerted by said automatic injection means, thereby disengaging said radially flexible leg from said stop surface, releasing said second elastic return means and causing said receptacle to move from said insertion position to said final position.

Preferably, said distal portion of said plunger rod comprises a barrel capable of receiving a portion of said proximal portion of said plunger rod, and said distal portion of said plunger rod comprises attenuating means designed to slow distal movement. of said proximal portion of said plunger rod into said distal portion of said plunger rod.

In an embodiment of the invention, said attenuating means comprise a rubbery material coated on the inner wall of said cylinder, said proximal portion of said plunger rod being provided at its distal end with at least one radial projection entering into contact with said rubbery material as said proximal portion of said plunger rod moves distally. Upon contact with such rubbery material, the proximal part of the plunger rod slows down and thus provides some time for the rest of the product to be completely expelled through the needle before the seconds deactivating means release the second retaining means and cause the receptacle to move to its final position.

In another embodiment of the invention, said attenuating means comprise a compressible material provided at the bottom of said barrel, the velocity of said proximal portion of said plunger rod being reduced when the distal end of said proximal portion of said plunger rod plunger comes into contact with said compressible material. Said compressible material may be a spring. By slowing the proximal portion of the plunger rod, some time is allowed for all of the product to be expelled before the receptacle is caused to move to its final position.

In a further embodiment of the invention, the inner diameter of said barrel decreases towards the bottom of said barrel and the distal end of said proximal portion of said plunger rod is provided with flexible tabs that rub against the inner walls of said barrel. said barrel as said proximal portion of said plunger rod moves distally.

In another embodiment of the invention, the inner walls of said cylinder are provided with flexible longitudinal legs which come into contact with a radial projection provided at the distal end of said proximal portion of said plunger rod, thereby reducing the velocity of said proximal portion of said plunger rod, as said proximal portion of said plunger rod moves distally.

In a further embodiment of the invention, said inner walls of said barrel are provided with a thread cooperating with a screw provided at the distal end of said proximal portion of said plunger rod, thereby reducing the speed of said portion. proximal portion of said plunger rod, as said proximal portion of said plunger rod moves distally.

In another embodiment of the invention, said cylinder walls are provided with several steps and the distal end of said proximal part of said plunger rod is provided with several radial flaps, the number of radial flaps that interact with said steps increasing to as said proximal portion of said plunger rod moves distally. Consequently, the more distally the proximal portion of said plunger rod moves, the greater the resisting force resulting from the interaction of the flaps with the steps. Thus, the proximal part of the plunger rod is slowed down and thus some time is allowed for all of the product to be expelled before the receptacle is caused to move to its final position.

In an embodiment of the invention, the device further comprises first retention means arranged to maintain said receptacle in said initial position, and first deactivation means arranged to release said first retention means and cause insertion of said needle into said receptacle. the injection site, said first deactivation means being manually actuated.

In a further embodiment of the invention, the device further comprises means for indicating to a user that substantially all of the product contained within said receptacle has been caused to pass through said outlet opening and said injection needle.

In another embodiment of the invention, the device further comprises tamper-evident means removably coupled with said housing to protect said needle prior to use of said device, said tamper-evident means being in a state pre-use and a post-use state, said post-use state preventing reuse of said tamper-evident means with said device.

Preferably, said post-use condition provides a visual indication that said tamper-evident means has been removed from said device.

In an embodiment of the invention, said tamper-evident means comprises a shield removal member and a needle shield, said post-use condition providing an indication that said tamper-evident means has been removed. of said device.

In an embodiment of the invention, the device further comprises a needle guard coupled with said housing and covering the needle prior to use of said device, removal of said needle guard being with limited or no rotation of said guard of needle

In another embodiment of the invention:

- said device further comprises a piston provided in said receptacle and movable within said receptacle, the distal movement of said piston causing said product to be expelled from said receptacle through said injection needle,

- said chamber is partially defined by the interior part of the receptacle located proximally with respect to said piston and is partially defined by the proximal part of said housing, said sealing cover joining the proximal end of said interior part to said housing through a absolute value friction force F,

- said chamber is filled in said initial state of said sealing cover with a pressurized fluid that exerts a pressure of absolute value Pc on said receptacle in the distal direction, with the intermediary of the piston,

- said device further comprises elastic return means for moving said receptacle from the insertion position to the final position, said elastic return means being coupled to said receptacle to exert on said receptacle a return force of absolute value Pe when said means elastic return tubes are at least in a partially compressed state,

- Pc being strictly greater than (Pe F) in the initial state of the sealing cover,

- decreasing Pc when part of the pressurized fluid escapes from the chamber through the ventilation outlet,

said retaining means being formed by Pc which is greater than (Pe F), said retaining means being released when Pe becomes equal to or greater than (Pc F).

Preferably, said pressurized fluid is provided to said chamber from a container present within said chamber, said container being sealed closed when said receptacle is in its initial position, said device being provided with a piercing button capable of creating an opening into said container when manual force is exerted on said piercing button, said pressurized fluid then being allowed to escape from said container and fill said chamber.

In another embodiment of the invention, said sealing cover is porous and forms said ventilation outlet. Preferably said device further comprises:

- a piston provided in said receptacle and movable within said receptacle, distal movement of said piston causing said product to be expelled from said receptacle through said injection needle,

- a piston rod provided with a head and a distal end, said piston rod being independent of said piston,

said chamber being defined by the volume delimited by the interior part of the receptacle located proximally with respect to said piston, the wall of the housing and the head of the piston rod, the proximal end of said receptacle joining the wall of the housing through a first porous sealing cover and the piston rod head joining the housing wall through a second porous sealing cover.

In an embodiment of the invention, the two sealing covers have a friction force against the wall of said housing of absolute value F,

- said chamber being filled in the initial state of said second sealing cover with a pressurized fluid that exerts a pressure of absolute value Pc on said receptacle in the distal direction, with the intermediary of the piston,

- said device further comprising first elastic return means for moving said receptacle from the initial position to the insertion position, said first elastic return means being coupled to said piston rod so as to exert on said piston rod a return force of absolute value Pi when said first elastic return means are at least in a partially compressed state,

- said device further comprising second elastic return means for moving said receptacle from the insertion position to the final position, said second elastic return means being coupled to said receptacle such that a return force of value is exerted on said receptacle absolute Pe when said second elastic return means are at least in a partially compressed state,

(Pc Pi) being greater than (Pe F) in the initial state of said second sealing cover,

decreasing Pc when part of the pressurized fluid escapes from the chamber through the ventilation outlet, said retaining means being formed by (Pc Pi) being greater than (Pe F), said retaining means being released when Pe becomes equal to or greater than (Pc F Pi).

In another embodiment of the invention, the deactivation means comprise a valve located in said first porous sealing cover, said valve being closed when said second porous sealing cover is in its initial state and being open when said second sealing cover is in its initial state. porous is in its final state, the opening of said valve releasing part of said retaining means.

Another aspect of the invention is a kit for a device for automatic injection of a product at an injection site, the product being transported by a receptacle having an open proximal end and a substantially closed distal end and having a reservoir defined therebetween, and a needle provided at the distal end and in fluid communication with the reservoir to provide an outlet opening for product from the receptacle, and a piston provided in the receptacle and movable with respect to the receptacle, causing movement of the piston that the product is expelled from the receptacle through the needle, characterized in that said kit comprises:

- a housing set comprising:

- an upper housing assembly,

- a lower housing assembly, at least one of said upper and lower housing assemblies being adapted to receive part of the receptacle, the receptacle being movable, when received within said at least one of said upper housing assemblies and lower, between an initial position, in which the tip of said needle does not extend beyond a distal end of said lower housing assembly, an insertion position, spaced distally relative to said initial position and in which the needle tip extends beyond said distal end of said lower housing assembly, and a final position wherein said needle is contained within one of said upper and lower housing assemblies, and

- means for connecting said upper housing and said lower housing to each other.

Preferably, said kit further comprises means for transporting at least one of said upper housing assembly and said lower housing assembly, said means of transporting said one of said upper housing assembly and said lower housing assembly in a default orientation.

The device of the invention will now be further described with reference to the following description and the accompanying drawings, in which:

Figure 1 is an exploded perspective view of an embodiment of the device of the invention,

figure 2 is a cross-sectional view of the device of figure 1 before use,

figure 3 is a partial cross-sectional view of the device of figure 1 showing the deactivation of the first retaining means,

Figure 4 is a cross-sectional view of the device of Figure 1 with the receptacle in the insertion position,

figure 5 is a cross-sectional view of the device of figure 1 in the injection stage, before timing,

Figure 6 is a cross-sectional view of the device of Figure 1 at the end of timing,

- figure 7 is a cross-sectional view of the device of figure 1 with the receptacle in the final position,

Figure 8 is a cross-sectional view of a variant of the device of the invention,

Figures 9 to 11 are cross-sectional views of a further variant of the device of the invention, respectively during the injection stage, during the timing stage, and in the final position,

- Figures 12 to 16 are partial cross-sectional views of various mechanical timing means,

Figure 17a is a front view of the distal end of the proximal part of a plunger rod suitable for forming part of the timing means of the device of the invention,

Figure 17b is a side view of the distal end of the proximal portion of the plunger rod of Figure 17a,

Figure 17c is a perspective cross-sectional view of the distal part of the plunger rod of Figure 17a,

- Figures 18 to 21 are cross-sectional views of an alternative of the device of the invention, respectively in the initial position, in the insertion position, in the end of injection position, and in the final position,

Figures 22 to 25 are cross-sectional views of another variant of the device of the invention, respectively in the initial position, in the insertion position, in the end of injection position, and in the final position,

Figures 26 and 27 are partial side views of a tamper evident means suitable for the device of the invention, respectively in the state prior to use and in the state after use,

Figures 28 and 29 are perspective views of means for transporting at least one of the upper housing and the lower housing of a device of the invention,

Figures 30 to 33 are cross-sectional views of another variant of the device of the invention, respectively in the initial position, in the insertion position, in the end of injection position, and in the final position.

Figure 1 shows an exploded perspective view of a device for automatic injection according to an embodiment of the present invention and generally designated with the reference number 1. The inventive device 1 comprises a housing 300 composed of an upper housing assembly 100 and a lower housing assembly 200 that can be connected together by means of a self-closing connection (110, 210) such as a screw-type connection, bayonet connection, or other means of releasably connecting two parts together or not. When the injection device is of the disposable type, the means for connecting the upper housing assembly 100 to the lower housing assembly 200 becomes inaccessible to the user. A receptacle 5, such as, for example, a syringe, is received in at least one of the upper and lower housing assemblies (100, 200). Preferably, the receptacle 5 is partially received in each of the upper and lower housing assemblies (100, 200), as discussed in more detail herein.

With reference to figures 1 and 2, the injection device comprises a receptacle 5 which is intended to receive a product 3 to be injected. The receptacle 5 has a distal end 5a and an open proximal end, which is provided, in the example shown, with a flange 5b. Said flange 5b can be useful for grasping said receptacle 5. The distal end 5a of receptacle 5 is substantially closed and is provided with an injection needle 6. This injection needle 6 provides an outlet opening of said receptacle 5 for the product 3 In Figures 1 and 2, the distal end of said receptacle 5 is also provided with a needle guard 2 which covers and protects the needle 6 prior to use of the device 1. The needle guard 2 also provides a means of sealing from the distal end of the receptacle 5 prior to use.

The device 1 of Figures 1 and 2 also comprises a piston 7 which is provided in the receptacle 5 and is movable with respect to said receptacle 5. A piston rod 8 is coupled to said piston 7 so as to cause said piston moves with respect to said receptacle 5, the movement of said piston 7 being intended to cause said product 3 to be expelled from said receptacle 5 through the injection needle 6 during the injection step and thereby perform the injection , as will be seen in Figures 4 through 6. As used herein, the term "coupled" refers to any permanent or temporary connection between two parts. For example, by way of illustration and not limitation, two parts may be attached to each other using a screw-type connection, by simple contact with each other, or with adhesive. Other types and ways of connecting two parts will be obvious to one skilled in the art and from the discussion provided herein.

The receptacle 5 is received inside a support 21 which has an overall tubular shape: said support 21 is open at both ends. Said support 21 is provided at its proximal end with at least two claws 21a in which the flange 5b of the receptacle 5 is fixed.

The device 1 of figures 1 and 2 further comprises a housing (9, 11) intended to receive the receptacle 5. In the example shown, said housing has a global tubular shape and is made up of two cylinders, a proximal barrel 9 and a distal barrel 11 which, as shown in Figure 2, snap together when the device is in use. In an embodiment of the invention not shown, the housing (9, 11) could be made in one piece. The needle protector 2 is attached to the housing (9, 11) and covers the needle 6 before the use of the device 1. In particular, as can be clearly seen from figure 2, the device 1 is provided with an element protector removal element 2a to which the needle protector 2 is fixed. Such a protector extraction element 2a is shown in greater detail in figures 26 and 27. The housing (9, 11) of the device 1 is coupled to the extraction element of protector 2a comprising a cover 90 to which the needle protector 2 is fixed. As shown in figure 27, the housing comprises grooves 95 to guide the translation of said cover 90 when the cover 90 is removed together with the removal of said protector removal element 2a in view of using said device 1. Consequently, when the user removes the protector extraction element 2a in order to use the device 1, the cover 90 follows the grooves 95 and does not broken. The needle guard 2, which is attached to the cap 90, also does not rotate. Thus, rotation of the needle tip 6 within the rubber forming the needle guard is prevented and also erosion of the central portion which could result from such potential rotation is prevented. Thus, the integrity and sterility of the needle 6 are preserved and the administration of the product can be safely completed.

As will appear later, the receptacle 5 can move in relation to said housing (9, 11) between an initial position, in which said needle 6 is contained within said housing (9, 11), an insertion position, separated distally in relation to said initial position and in which said needle 6 is exposed along a predetermined length, and a final position in which said needle 6 is contained within said housing (9, 11).

The proximal cylinder 9 of the housing is provided at its distal end with at least two flexible teeth 10 which can deflect radially and outwards.

As shown in figure 2, the distal cylinder 11 of the housing is provided in its distal part with at least two flexible tabs 12 that can be deflected radially and outwards. The distal end of said distal cylinder 11 is provided with an inner ridge 13: the distal face 13a of said inner ridge forms a bearing surface for the device 1 at the injection site 4 (see Figure 4).

The device 1 of Figures 1 and 2 further comprises a sleeve 16 having a closed proximal end 17 and an open distal end 18. Said sleeve 16 is intended to at least partially receive said support 21. The proximal end 17 of the sleeve 16 it comprises a ventilation outlet 19. The ventilation outlet 19 may be a small hole. For example, the diameter of said hole may range from 15 microns to 25 microns. Alternatively, the hole is replaced by a membrane vent element. In such a case, the diameter of said membrane may be about 1 mm. The distal end 18 of said sleeve 16 is provided with an outer radial rim 20.

The device 1 of figures 1 and 2 further comprises a sealing cover 27 which is intended to be coupled to the head 8a of the plunger rod 8.

The device 1 of figures 1 and 2 also comprises a ring 14 which is intended to receive the distal part of said support 21 and to engage with said receptacle 5 at least from the insertion position to the final position of said receptacle 5. ring 14 has a proximal part and a distal part, the diameter of said proximal part being less than the diameter of said distal part, said proximal and distal parts being joined by a radial wall 15. The radial wall 15 has a proximal face 15a and a distal face 15b.

The device 1 of figures 1 and 2 further comprises a push button 22 intended to be housed between the proximal cylinder 9 of said housing and said sleeve 16. The push button 22 has the overall shape of a closed cylinder at its proximal end: the end The proximal part of the push button 22 forms a push surface 22a for the user to exert manual pressure in view of the activation of the device 1. The inner wall of the proximal part of the push button 22 is provided with an inner rim 22b. The push button 22 is further provided at its distal end with at least two distal legs 23.

In the device 1 according to figures 1 and 2, a first coil spring 24 is provided between the push button 22 and the sleeve 16. As appears from figure 2, the distal end of the first coil spring bears on the face proximal of said outer radial rim 20 of said sleeve 16, and the proximal end of the first helical spring bears on the distal face of the inner rim 22b of the push button 22. A second helical spring 25 is provided between said support 21 and said ring 14 : as shown in figure 2, the distal end of the second helical spring 25 rests on the proximal face 13b of the inner ridge 13 of the distal cylinder 11 and the proximal end of said second helical spring 25 rests on the distal face 15b of said radial wall 15 of said ring 14.

The device 1 of figures 1 and 2 is finally provided with a protector extraction element 2a to remove the needle protector 2 when the user decides to carry out the injection. As will be seen later, the shield removal member 2a and the needle shield 2 are removably engaged with the housing (9, 11) and act as tamper-evident means to protect the needle 6 before use of the device 1, said tamper-evident means being able to adopt a pre-use state and a post-use state , said post-use state preventing the reuse of the tamper-evident means with the device 1.

The operation of the device 1 will now be explained with reference to Figs. 2 to 7.

In figure 2 the device 1 is shown before use, as it is provided to the user. In this position, the sealing cover 27 is in an initial state in which it hermetically closes and seals the proximal portion of said sleeve 16, thereby defining a chamber 26 having an initial volume. In the position of figure 2, said initial volume of said chamber 26 contains a certain amount of pressurized fluid, for example pressurized air. Alternatively, the fluid could be another gas or a viscous liquid, such as oil or grease. As will be seen later, the sealing cover 27 can move between said initial state and a final state in which at least part of said pressurized fluid has escaped through the ventilation outlet 19.

In the position before use as shown in Figure 2, the receptacle is in its initial position. It is retained in said initial position by engaging said flexible teeth 10 of said proximal cylinder 9 in said outer radial rim 20 of said sleeve 16, said flexible teeth 10 and said outer radial rim 20 acting as first retaining means, under the pressure of said first coil spring 24, which is in a pressurized state.

In this position, the needle 6 is protected by the needle guard 2 which is attached to the guard removal member 2a. Accordingly, the shield removal member 2a and the needle shield 2 form the tamper-evident means which are in their state prior to use.

When the user decides to perform the injection, he first removes the protector removal element 2a: by this operation, he also removes the needle protector 2. The tamper-evident means, formed by the protector extraction element 2a and the needle protector of needle 2 are therefore in their post-use state. The withdrawal of the needle guard 2 is completed with limited or no rotation of the needle guard 2. Thus, possible erosion of the central part caused by the point of the needle 6 rotating in the rubber forming the guard is prevented. needle 2.

After extracting the protector, the receptacle 5 is still held in its initial position by the first retaining means which are in the same position as described in figure 2.

In a stage not shown, the user then applies the device 1 to the injection site 4 by means of the support surface 13a of said distal cylinder 11. He then manually actuates the push button 22 by exerting a distal force on the thrust surface 22a. so as to cause said push button 22 to move distally.

As shown in figure 3, during this movement, the distal legs 23 come into contact with said flexible teeth 10, causing said flexible teeth 10 to deflect radially and outwards. As a consequence, said flexible teeth 10 disengage from said outer radial rim 20 in which they were previously engaged. Therefore, the first coil spring 24 is free to return to a normal state and extends distally, dragging the sleeve 16 with it. The sleeve 16 is coupled to said plunger rod 8 by means of the sealing cover 27 which is fixed on the head 8a of the plunger rod 8, the plunger rod 8 being dragged distally by the sleeve 16. Furthermore, the distal end of the plunger rod 8 is threaded inside the piston 7, the plunger rod 8 engaging said receptacle 5, by at least from the initial position to the insertion position of the receptacle, by means of the frictional force exerted by the outer walls of said piston 7 on the inner walls of said receptacle 5. Consequently, the receptacle 5 also drags distally, causing the needle 6 to penetrate the injection site 4 until the distal end of said support 21 abuts on the proximal face 13b of the inner ridge 13 of said distal cylinder 11, as shown in figure 4.

As shown in figure 4, the receptacle 5 is thus in the insertion position and the injection of the product 3 can begin. The injection is automatically actuated by means of the first helical spring 24 which continues to extend distally towards its normal state. Once receptacle 5 is prevented from moving distally by stopping said support 21 against inner ridge 13, the force of first coil spring 24 overcomes the force of static friction and causes piston 7 to move distally within from said receptacle 5, thereby expelling said product 3 through said injection needle 6.

Once the piston 7 is close to said distal end 5a of the receptacle 5 and abuts more or less at said distal end 5a, the force of said first helical spring 24 overcomes the frictional force of the sealing cover 27 against the walls interiors of said sleeve 16 and said sleeve continues to move distally, causing part of the pressurized fluid present in said chamber 26 to escape through the outlet of vent 19, as shown in figure 5.

As shown in figure 5, in the device 1 of the invention, although the piston 7 has reached the distal end of the receptacle 5, said receptacle 5 is prevented from moving from its insertion position to its final position, provided that substantially all of the product has not been expelled, and especially provided that said sealing cover 27 has not reached its final state (see Figure 6): in fact, as clearly appears from Figure 5, it is still prevented that the second helical spring 25, which is intended to move said receptacle from its insertion position to its final position, extends proximally by means of the engagement of said flexible tabs 12 on the stop surface 15a.

The time it takes for the sealing cover 27 to move from its initial state to its final state allows all of the liquid to be expelled through the injection needle 6.

As shown in figure 6, the sleeve 16 continues to move distally, under the force exerted by said first coil spring 24, until the sealing cover 27 comes into contact with the proximal end of said sleeve 16 and substantially all of the fluid The pressure present in the chamber 26 has escaped through the ventilation outlet 19. During this movement, the outer radial rim 20 comes into contact with said flexible tabs 12 which are then caused to deflect radially and outwards, such as is shown in Figure 6. The radial wall 15 is thus disengaged from said flexible tabs 12 and the second helical spring 25 is free to move proximally. As the force of said second helical spring 25 is greater than the force of the first helical spring 24, said second helical spring 25 pushes said ring 14, which engages said support 21 in the proximal direction, thanks to an outer rim 21c provided on said support 21 on which the proximal end 14a of said ring abuts.

Being the receptacle 5 fixed to said support 21, it is made to move proximally and retract inside said distal cylinder 11 to reach its final position, inside said housing (9, 11), as shown in figure 7 .

Thanks to the timing means of the device of the invention, the retraction of the needle into the housing is an indication to a user that substantially all of the product contained within the receptacle has passed through the needle outlet opening. injection 6.

In the final position, the needle 6 is contained within said housing (9, 11) and therefore the device 1 is ready for disposal, without any risk of accidental needlestick injury.

In an alternative embodiment of the invention not shown, the frictional force of the sealing cover 27 against the inner walls of said sleeve 16 is such as to allow said sealing cover 27 to start moving from its initial state as soon as start the injection.

In another embodiment of the invention not shown, the force of the first coil spring 24 is reduced by adding a third spring to move said sealing cover 27 from its initial state to its final state. Such an embodiment allows to reduce the force with which the support 21 or the receptacle 5 touches the inner ridge 13 or the injection site 4, especially the skin, and provides some comfort to the user.

Figure 8 shows a variant of the device 1 of Figures 1 to 7, in which the sleeve that forms the chamber merges with the push button. The corresponding references have been maintained with the same elements as in figures 1 to 7.

As can be seen from Figure 8, the deactivation means and the chamber are provided as a sleeve 30 which is closed at its proximal end. Said proximal end forms a thrust surface 30a for the user to exert manual and distal pressure when he wishes to activate the device 1. The proximal end comprises a ventilation outlet 29b. A sealing cover 29a is provided on the head of a piston rod 8.

The sleeve 30 is provided with at least one external projection 31 and said housing 9 is provided with a stop element 32. In the initial position of the receptacle 5, said external projection 31 abuts against said stop element 32, forming said projection outer part 31 and said stop element 32 first means for retaining said receptacle 5 in the initial position.

In steps not shown, after removing the needle guard and the guard removal member, the user applies the device 1 to the injection site and pushes distally on the pushing surface 30a causing said sleeve 30 to move distally. Manual pressure exerted on the sleeve 30 by the user overcomes said stop element 32 and the first helical spring 24 is then free to move distally. The first helical spring 24 pushes the outer radial rim 20 of said sleeve 30, thereby performing the insertion of the needle 6, the injection and the timing as observed for the device 1 of figures 1 to 7. It is made that the receptacle 5 moves from its insertion position to its final position by the second helical spring 25 only when the sealing cover 29a has reached its final state by coming into contact with the proximal end of said sleeve 30.

Figures 9 to 11 show another variant of the device 1 of the invention, in which the plunger rod is provided in two parts, a proximal part and a distal part, which separate when said piston comes into contact with the end distal to said receptacle. The corresponding references have been maintained with the same elements as in figures 1 to 7.

In figure 9 a device 1 according to the invention is shown comprising a plunger rod 40 provided in two parts, a proximal part 41 and a distal part 42. The proximal part 41 of the plunger rod 40 is provided at its proximal end with a head 49 and at its distal end a radial projection 44. The distal part 42 of the plunger rod comprises a cylinder, the inner walls of which are coated with a rubbery material 43.

The housing 9 is provided on its inner wall with at least two radially flexible legs 46.

The device 1 further comprises a ring 48, said ring 48 being coupled to said receptacle 5 when said receptacle moves from its insertion position to its final position. Said ring 48 comprises a stop surface 47.

In figure 9, the device 1 is in the injection position, said receptacle 5 being in the insertion position. The first coil spring 24 automatically performs the injection by pushing head 49 of plunger rod 40 distally. In this position, the force exerted by the first coil spring 24 on plunger rod 40 is not great enough to separate said rod from plunger in two parts. Piston 7 is caused to move distally, thereby expelling product 3 through injection needle 6.

When said piston is close to the distal end of said receptacle 5, as shown in figure 10, said distal part 42 of said plunger rod 40 is stopped, but said proximal part 41 of said plunger rod 40 is allowed to continue. its distal movement under the force exerted by said automatic injection means, i.e. the first helical spring 24. The radial projection 44 then comes into contact with the rubbery material 43 and the distal movement of the proximal part 41 of the plunger rod 40 it slows down, due to the interaction between the radial projection 44 and the rubbery material 43. Some time is then allowed for all of the product 3 to be expelled before retraction of the receptacle 5 into the housing 9.

In fact, during the distal movement of the proximal portion 41 of the plunger rod 40, the head 49 contacts the flexible legs 46 of the housing 9 and causes them to deflect radially. The stop surface 47 thereby disengages from said flexible legs 46 and the second helical spring 25 is free to return to its normal state and extend proximally, as shown in Figure 11.

Only then is the receptacle 5 made to move from its insertion position to its final position.

An alternative timing means is shown in Figures 12 to 17c in the form of a plunger rod 40 provided in two parts, a proximal part 41 and a distal part 42. Corresponding references have been retained with the same elements as in Figures 9 to 11.

In Figures 12 and 16 there are shown piston rods 40 similar to those of Figures 9 to 11, in which the rubbery material has been replaced by a compressible material (50, 51): in Figure 16, the compressible material is a spring 51. When the distal end of the proximal portion 41 of the plunger rod 40 comes into contact with the compressible material (50, 51), the velocity of the proximal portion 41 of the plunger rod 40 is reduced and therefore it allows some time for substantially all of the product 3 to be expelled before the head of the plunger rod cooperates with the second retaining means so as to cause retraction of the receptacle.

In Fig. 13 a piston rod 40 is shown in two parts, in which the diameter of the cylinder 42, which forms the distal part of the piston rod, decreases towards the bottom of said cylinder. The distal end of the proximal part 41 of said plunger rod 40 is provided with flexible tabs 52 which rub against the inner walls of said cylinder, causing the proximal part 41 to slow down when it moves distally.

In Figure 14, a plunger rod 40 is shown for which the inner walls of said cylinder 42 are provided with a thread 55 cooperating with a screw 56 provided at the distal end of said proximal portion 41 of said plunger rod, thereby reducing the velocity of said proximal portion 41 of said plunger rod, as said proximal portion of said plunger rod moves distally.

In Figure 15 a plunger rod 40 is shown for which the inner walls of said cylinder 42 are provided with longitudinal flexible legs 53 that come into contact with a radial projection 54 provided at the distal end of said proximal part 41 of said plunger rod, thereby reducing the velocity of said proximal portion 41 of said plunger rod, as said proximal portion of said plunger rod moves distally.

In figures 17a to 17c a piston rod is shown for which said cylinder walls are provided with several steps 57 and the distal end of said proximal part of said piston rod is provided with several radial flaps 58, increasing the number of steps. radial flaps interacting with said steps as said proximal portion of said plunger rod moves distally.

In figures 18 to 21 an alternative embodiment of the device 1 of the invention is shown. Reference numbers referring to the same elements as for Figures 1 to 7 have been retained.

The device 1 of figures 18 to 21 comprises a chamber 59 partially defined by the inner part 61 of the receptacle located proximally with respect to the piston 7. The rest of the chamber 59 is defined by the walls of the housing 68 that receive the receptacle 5. A sealing cover 60 joins the proximal end 5b of said inner part 61 to the housing 68 through a friction force of absolute value F. At its proximal end, the chamber 59 comprises a ventilation outlet 63. The chamber 59 also comprises a container 65, preferably composed of rigid walls.

In the initial position of the receptacle, as shown in figure 18, this container 65 is sealed closed and is filled with a pressurized fluid 64.

The device of Figures 18 to 21 further comprises a piercing button 66 which can create an opening 67 in said container when a manual force is exerted on said piercing button 66. The size of the opening 67 is much larger than the size of ventilation outlet 63.

Furthermore, the device 1 of figures 18 to 21 comprises a sleeve 69 received within said housing 68 and receiving said receptacle 5. The sleeve 69 comprises in its distal area an inner radial rim 70. A helical spring 62 is placed between said receptacle 5 and said sleeve 69, the proximal end of said spring 62 resting on the distal face of said proximal end of said receptacle 5 and the distal end of said spring resting on the proximal face of said inner radial rim 70 of said sleeve 69. The absolute value of the return force exerted by the spring 62 on said receptacle 5 when said spring is at least in a partially compressed state is denoted Pe.

The operation of the device 1 of figures 18 to 21 will now be described.

Device 1 is provided to the user in its initial position shown in figure 18.

In this position, the needle 6 is protected by a needle protector 2 and a protector removal member 2a.

Container 65 is filled with pressurized fluid 64. When the user wishes to continue administration of product 3, he removes shield removal member 2a and needle shield 2, applies device 1 to injection site 4 and exerts a manual force on the piercing button 66. The piercing button 66 penetrates a wall of the container 65 and creates an opening 67 as shown in figure 19.

Pressurized fluid 64 is then allowed to escape from container 65 through opening 67 and begins to fill chamber 59. As shown in Figure 19, as pressurized fluid 64 spreads into chamber 59 pushes on sealing cover 60 and thus on receptacle 5, which is caused to move distally. As a consequence, the needle 6 penetrates the injection site and the device 1 is in the insertion position. Once the distal movement of the receptacle 5 stops, thanks to the proximal end 5b of said receptacle 5 resting on the distal end of the sleeve 69, the pressure exerted by the pressurized fluid 64 in the chamber 59 causes the piston 7 move distally.

As piston 7 moves distally, product 3 is injected into injection site 4 through needle 6 until piston 7 is close to the distal end of receptacle 5, as shown in Figure 20. During the insertion and injection steps, some of the pressurized fluid 64 has been allowed to escape from the chamber 59 through the vent 63. However, since the size of the vent 63 is much smaller than opening 67, only an insignificant amount of pressurized fluid 64 has escaped from said chamber 59.

When the piston 7 is close to the distal end of the receptacle 5, as shown in figure 20, the pressurized fluid 64 exerts a pressure on said receptacle 5 of absolute value Pc.

During the injection stage and until the piston 7 is close to the distal end of the receptacle 5, Pc is greater than (Pe F). As pressurized fluid 64 escapes through vent outlet 63, Pc decreases. Furthermore, during the insertion step, the spring 62 has been compressed and its return force Pe has increased.

Therefore, during the injection stage, the retention media are formed by Pc which is greater than (Pe F). When Pe becomes equal to or greater than (Pc F), the retaining means is released and the spring 62 is allowed to return to its expanded state. The time required for Pe to be equal to or greater than (Pc F) allows the injection to be fully completed.

The return of spring 62 to its expanded state is subject to the flow of fluid 64 out of chamber 59 through vent outlet 63.

Consequently, due to the small size of the vent 63, the return of the spring to its expanded state will occur slowly and the needle 6 will slowly retract into said housing 68.

An alternative to the embodiment of Figures 18 to 21 is shown in Figures 22 to 25.

The device 1 of figures 22 to 25 comprises a chamber 79 partially defined by the interior part 71 of the receptacle 5 located proximally with respect to the piston 7. The rest of the chamber 79 is defined by the walls of the housing 72 that receive the receptacle 5 and by the head 73 of a piston rod 74. The distal end 77 of the piston rod 74 is not fixed to the piston 7.

A first sealing cover 75 joins the proximal end 5b of said inner part 71 to the housing 72. A second sealing cover 76 joins the head 73 of the piston rod 74 to the housing 72 and therefore seals the chamber 79. The two sealing covers sealing (75, 76) are porous sealing covers. Consequently, both form an outlet vent element for any pressurized fluid contained in chamber 79. Together, the two sealing covers (75, 76) present a frictional force against the wall of housing 72 of absolute value F.

The device 1 of figures 22 to 25 comprises a sleeve 78 received within said housing 72 and receiving said receptacle 5. The sleeve 78 comprises in its distal area an inner radial rim 80. A helical spring 81 is placed between said receptacle 5 and said sleeve 78, the proximal end of said spring 81 resting on the distal face of said proximal end of said receptacle 5 and the distal end of said spring resting on the proximal face of said inner radial rim 80 of said sleeve 78. The value The absolute value of the return force exerted by the spring 81 on said receptacle 5 when said spring is at least in a partially compressed state is denoted Pe.

The device 1 of figures 22 to 25 further comprises a stop element 82 provided on the inner wall of said housing 72. The device 1 also comprises a push button 83 having two distal legs 84.

Head 73 of piston rod 74 is provided with two proximal flexible tabs 85. The proximal end of housing 72 is provided with two stop surfaces 86.

A helical spring 87 is provided within push button 83 and the proximal portion of head 73 of piston rod 74. The proximal end of spring 87 bears against the distal face of push button 83, and the distal end of spring 87 bears on the proximal face of the proximal part of the head 73 of the piston rod 74. The absolute value of the return force exerted by the spring 87 on said piston rod 74 when said spring is at least in a partially compressed state is called Pi.

The operation of the device 1 of figures 22 to 25 will now be described.

Device 1 is provided to the user in its initial position shown in figure 22.

In this position, the needle 6 is protected by a needle protector 2 and a protector removal member 2a. Proximal tabs 85 of head 73 of piston rod 74 engage stop surfaces 86 of housing 72. Spring 87 is in a compressed state.

When the user wishes to continue with the administration of the product 3, he removes the protector removal element 2a and the needle protector 2, applies the device 1 to the injection site 4 and exerts a manual force on the push button 83. Therefore , push button 83 moves distally and its distal legs 84 contact flexible tabs 85 of housing 72. Under pressure from distal legs 84, flexible tabs 85 deflect radially and become disengaged from abutment surfaces. 86. Spring 87 is then free to return to its expanded state and pushes piston rod 74 distally. Being the friction F of the sealing covers (75, 76) less than the friction force of the piston 7 against the inner wall of the receptacle 5, said receptacle 5 is dragged in the distal direction, thus performing the insertion of the needle 6 at injection site 4, as shown in figure 23.

Once the distal movement of the receptacle 5 is stopped, thanks to the proximal end 5b of said receptacle 5 abutting the distal end of sleeve 78, the force of spring 87 overcomes the static friction force and piston 7 is pushed distally by the distal end of piston rod 74, thereby injecting product 3 into injection site 4.

As piston 7 and piston rod 74 move distally, the volume defining chamber 79 decreases, as shown in Figure 24. Consequently, fluid, such as gas or air, present within of said chamber 79 is put under pressure. Furthermore, before the piston 7 approaches the distal end of the receptacle, as shown in figure 24, the distal movement of the piston rod 74 is stopped by the stop element 82 provided on the inner wall of said housing 72. The pressurized fluid, reference numeral 88 in Figure 24, thus fills the space between piston 7 and distal end 77 of piston rod 74, thereby holding piston 7 against the distal end of the receptacle. 5 and allowing extra time for the injection to be fully completed. The pressure of pressurized fluid 88 is designated Pc.

During the insertion step, the spring 81 has been compressed and its return force Pe has increased.

During the injection stage, and after the piston 7 approaches the distal end of the receptacle 5, the pressurized fluid escapes through the porous sealing covers (75, 76). Therefore, once the piston 7 has reached the termination of the distal end of the receptacle 5 and substantially all of the product has been made to pass through the exit opening of the injection needle 6, Pc decreases as a consequence of the fluid that it escapes from chamber 79 through porous sealing covers (75, 76).

During the injection stage, the retention media are formed by (Pc Pi) which is greater than (Pe F). When Pe becomes equal to or greater than (Pc F Pi), the retaining means is released and the spring 81 is allowed to return to its expanded state. The time required for Pe to be equal to or greater than (Pc F Pi) allows the injection to be fully completed.

Returning to its expanded state, spring 81 draws needle 6 back into housing 72 and device 1 is secure.

Referring to Figures 26 and 27, partial views of a protector extraction element 2a suitable as a tamper evident means for a device of the invention are shown. The protector extraction element 2a is made up of a cover 90 and a ring 91 connected to each other by breakable bridges 92.

In the state prior to use, as shown in FIG. 26, the protector removal element 2a is fixed in the housing 93 of a device according to the invention. Cap 90 and ring 91 are made in one piece, for example by injection moulding, and are connected to each other by means of breakable bridges 92.

Housing 93 is provided with stop elements 94 that prevent a user from breaking bridges 92 by applying a proximal force on cover 90.

When a user is ready to use the device of the invention, he or she removes the shield removal element 2a by pulling distally on the cover 90 so that it is removed from the housing 93, thereby breaking the breakable bridges 92.

As can be seen in figure 27, the housing 93 is provided with grooves 95 that guide the translation of the cover 90 as it is removed. Thus, the shield removal member and needle shield (not shown) within cap 90 are removed with limited or no rotation of the needle (not shown). Therefore, erosion of the center portion caused by the needle tip rotating in the rubber forming the needle guard is prevented.

In Fig. 27, the tamper-evident means formed by the protector removal member 2a is in its post-use state. Any user, provided with the device with the protector removal element 2a in this state, can immediately notice, thanks to the broken bridges 92, that the device has been tampered with. The post-use state of the shield removal member demonstrates an indication that the tamper evident media has been removed from the device.

Furthermore, due to the broken jumpers 92, it is impossible for someone to replace the cap in its pre-use state.

Shown in Figure 28 is a tray 400 for transporting upper housing assemblies 100 in a predetermined direction. The transport means 400 of figure 28 can especially transport a plurality of upper housings 100, all arranged in the same direction. Such a tray comprises a plurality of holes 402 intended to receive the upper housing assemblies 100. Such a tray 400 is useful for transporting and/or handling upper housings of a device of the invention during all of the various stages of manufacturing, filling, packaging , etc.

Shown in Figure 29 is a tray 401 similar to the tray 400 of Figure 28, the tray 401 in the example shown carrying a plurality of lower housing assemblies 200 of a device of the invention, in a predetermined orientation.

Figures 30 to 33 show a variant of the device of figures 22 to 25. The references designating the same elements as in figures 22 to 25 have been maintained.

The device 1 of figures 30 to 33 comprises a chamber 96 partially defined by the interior part 71 of the receptacle 5 located proximally with respect to the piston 7. The rest of the chamber 96 is defined by the walls of the housing 72 that receive the receptacle 5 and by the head 73 of a piston rod 74. The distal end 77 of the piston rod 74 is not fixed to the piston 7.

A first sealing cover 97 joins the proximal end 5b of said inner part 71 to the housing 72. A second sealing cover 98 joins the head 73 of the piston rod 74 to the housing 72 and therefore seals the chamber 96. The two sealing covers sealing (97, 98) are porous sealing covers. Consequently, both form an outlet vent element for any pressurized fluid contained in chamber 96. Together, the two sealing covers (97, 98) present a frictional force against the wall of housing 72 of absolute value F.

The device 1 of figures 30 to 33 comprises a sleeve 102 received inside said housing 72 and receiving said receptacle 5. The sleeve 102 comprises in its distal area an inner radial rim 103 and in its proximal end a flexible tongue 104 provided with a stop surface 105. A helical spring 106 is placed between said receptacle 5 and said sleeve 102, the proximal end of said spring 106 resting on the distal face of said stop surface 105 through the intermediary of a ring 107 and the end resting distal of said spring 106 on the proximal face of said inner radial rim 103 of said sleeve 102.

The device 1 of figures 30 to 33 further comprises a push button 83 having two distal legs 84.

Head 73 of piston rod 74 is provided with two proximal flexible tabs 85. The proximal end of housing 72 is provided with two stop surfaces 86.

A helical spring 87 is provided within push button 83 and the proximal portion of head 73 of piston rod 74. The proximal end of spring 87 bears against the distal face of push button 83, and the distal end of spring 87 bears on the proximal face of the proximal part of the head 73 of the piston rod 74.

The operation of the device 1 of figures 30 to 33 will now be described.

Device 1 is provided to the user in its initial position shown in figure 30.

In this position, the needle 6 is protected by a needle protector 2 and a protector removal member 2a. Proximal tabs 85 of head 73 of piston rod 74 engage stop surfaces 86 of housing 72. Spring 87 is in a compressed state.

When the user wishes to continue with the administration of the product 3, he removes the protector removal element 2a and the needle protector 2, applies the device 1 to the injection site 4 and exerts a manual force on the push button 83. Therefore , push button 83 moves distally and its distal legs 84 contact flexible tabs 85 of housing 72. Under pressure from distal legs 84, flexible tabs 85 deflect radially and become disengaged from abutment surfaces. 86. Spring 87 is then free to return to its expanded state and pushes piston rod 74 distally. Being the friction F of the sealing covers (97, 98) less than the friction force of the piston 7 against the inner wall of the receptacle 5, said receptacle 5 is dragged in the distal direction, thus performing the insertion of the needle 6 at injection site 4, as shown in figure 31.

Once the distal movement of socket 5 is stopped, for example by the distal end of socket 5 coming into contact with injection site 4, the force of spring 87 overcomes the force of static friction and piston 7 is pushed distally. by the distal end of the piston rod 74, thereby injecting the product 3 into the injection site 4.

As piston 7 and piston rod 74 move distally, the volume defining chamber 96 decreases. Consequently, the fluid, eg gas or air, present within said chamber 96 is put under pressure. This fluid fills the space between the piston and the distal end 77 of the piston rod 74. Due to this gap, as piston 7 approaches the distal end of receptacle 5, head 73 of piston rod 74 is not in contact with sealing cover 97. The porosity of sealing covers (97, 98) allows said sealing covers act as a vent and some of the pressurized fluid present in chamber 96 is allowed to escape from said chamber 96 slowly, allowing sufficient time for substantially all of the product 3 to be expelled. When substantially all of the product 3 has been expelled product, piston rod 74 is allowed to move slowly distally, and head 73 of piston rod 74 contacts valve 99 of sealing cover 97. Valve 99 is pushed distally and enters contact with flexible tab 104 which deflects radially, releasing ring 107 and spring 106. Released spring 106 begins to move proximally but is slowed by the force of the pressurized fluid present. e into chamber 96. With proximal movement of spring 106, ring 107 contacts valve 99 and opens it. Pressurized fluid still present in chamber 96 is then allowed to escape through open valve 99 and spring 106 rapidly returns to its expanded state.

Returning to its expanded state, spring 106 draws needle 6 back into housing 72 and the device is secure as shown in Figure 33.

The device of the invention is very easy to use and very safe. It allows a patient to automatically inject a product without any risk of needlestick injury, before, during and after use. In particular, it allows retraction of the needle within the device only after substantially all of the product has been injected. Therefore, injections of inadequate doses of product are prevented.

Claims (11)

1. Device (1) for automatic injection of a product at an injection site, the injection device (1) comprising: a receptacle (5) that has an open proximal end and a substantially closed distal end and that is intended to receive the product, and provided at its distal end with an injection needle (6) that provides an outlet opening of the receptacle (5 ), a housing (9) intended to receive, at least partially, the receptacle (5), the receptacle (5) being able to move in relation to the housing (9) between an initial position, in which the needle (6) is contained within the housing (9), an insertion position, distally separated in relation to the initial position and in which the needle (6) is exposed along a predetermined length, and a final position in which the needle (6 ) is contained within the housing (9), a piston (7), provided in the receptacle (5) and movable with respect to the receptacle (5), timing means in the form of a piston rod (40) having a proximal part (41) and a distal part (42), the piston rod (40) being coupled to the piston (7) to cause the piston ( 7) moves with respect to the receptacle (5), causing the movement of the piston (7) to expel the product from the receptacle (5) through the injection needle (6), elastic return means (25) coupled to the housing (9) to move the receptacle (5) from the insertion position to the final position, and automatic injection means (24), arranged to automatically cause the plunger rod (40) to push the piston (7) distally, characterized by what the device (1) further comprises retaining means, formed at least partially in the housing (9) and arranged to maintain the receptacle (5) in the insertion position, and deactivation means, formed in the proximal part of the plunger rod (40) and arranged to automatically release the retaining means and cause the receptacle (5) to move to the final position, happening that, when the piston (7) comes into contact with the distal end of the receptacle (5), under the force exerted by the automatic injection means (24) on the proximal part of the plunger rod (40), the distal part of the plunger rod (40) is thereby stopped and the proximal part of the plunger is allowed to continue its distal movement under the force exerted by the automatic injection means (24) for a certain time until the deactivation means cooperate with the retaining means to make the receptacle (5) move from the insertion position to the final position. Device (1) according to claim 1, further comprising a ring (48), the ring (48) being coupled to the receptacle (5) when the receptacle (5) moves from the insertion position to the final position, in which the retention means comprise a radially flexible leg (46) located on an inner wall of the housing (9), engaged with an abutment surface (47) of the ring (48), when the receptacle (5) is in the insertion position, the deactivation means comprises a head of the proximal portion of the plunger rod (40), and the plunger rod head (40) deflects the radially flexible leg (46) under the force exerted by the automatic injection means, thereby disengaging the radially flexible leg (46) from the stop surface (47), releasing the elastic return means and causing the receptacle (5) to move from the insertion position to the final position. Device (1) according to claim 2, wherein the distal portion of the plunger rod (40) comprises a cylinder that can receive a portion of the proximal portion of the plunger rod (40), and the distal portion of the plunger rod The plunger rod (40) comprises an attenuating means designed to slow the distal movement of the proximal portion of the plunger rod (40) within the distal portion of the plunger rod (40). Device (1) according to claim 3, wherein the attenuating means comprises a rubbery material (43) coated on an inner wall of the barrel, and the proximal portion of the plunger rod (40) is provided at a distal end of at least one radial projection that comes into contact with the rubbery material when the proximal part of the plunger rod (40) moves distally. Device (1) according to claim 3, in which the attenuation means comprise a compressible material (50, 51) provided in the lower part of the cylinder, the speed of the proximal part of the piston rod (40) being reduced when A distal end of the proximal portion of the plunger rod (40) contacts the compressible material. Device (1) according to claim 5, in which the compressible material (50, 51) is a spring. Device (1) according to claim 1, in which the distal part of the plunger rod (40) comprises a cylinder that can receive a part of the proximal part of the plunger rod (40), decreasing the internal diameter of the cylinder toward the bottom of the barrel and a distal end of the proximal portion of the plunger rod (40) being provided with flexible tabs (52) which rub against the interior walls of the barrel when the proximal portion of the plunger rod (40) is extended. move distally. Device (1) according to claim 1, in which the distal part of the plunger rod (40) comprises a cylinder that can receive a part of the proximal part of the plunger rod (40) and the interior walls of the cylinder are provided with longitudinal flexible legs (53) that contact a radial projection (54) provided on a distal end of the proximal part of the plunger rod (40), thereby reducing the velocity of the proximal part of the plunger rod (40). plunger (40), when the proximal part of the plunger rod (40) moves distally. Device (1) according to claim 1, in which the distal part of the plunger rod (40) comprises a cylinder that can receive a part of the proximal part of the plunger rod (40) and the interior walls of the cylinder are provided with a thread (55) which cooperates with a screw (56) provided at a distal end of the proximal part of the plunger rod (40), thereby reducing the velocity of the proximal part of the plunger rod (40), when the proximal portion of the plunger rod (40) moves distally. Device (1) according to claim 1, in which the distal part of the plunger rod (40) comprises a cylinder that can receive a part of the proximal part of the plunger rod (40) and the inner walls of the walls of the cylinder are provided with a plurality of steps (57) which interact with a plurality of radial flaps (58) at a distal end of the proximal portion of the plunger rod (40), the number of radial flaps (58) interacting with the number of radial flaps (58). plurality of steps (57) which increase as the proximal portion of the plunger rod (40) moves distally. Device (3) according to claim 2, in which the automatic injection means comprise a spring (24) and the deactivation means are a head (49) attached to the proximal part (41) of the plunger rod (40). ) and the spring (24) maintains contact with the head (49) when the receptacle (5) is in the initial position, the insertion position and the final position.