Device for injection of a product, in particular for medical use

A medical device for the injection of a product. The device includes a body receiving an injection needle and a container containing the product to be injected; an arrangement for holding the needle in an injection position; an arrangement for holding the container in a position permitting injection; and, a piston engaged in the container. The device also includes first and second actuators which make it possible, at the end of the injection, to respectively release the arrangement for holding the needle before, or simultaneously to, the release of the arrangement for holding the container. A container support is mounted slidably on the body and is displaceable relative to the latter in order to perform the injection. The container support is held in a standby position before injection with the needle being held in the injection position.

FIELD OF THE INVENTION

The present invention relates to a device for injection of a product, in particular for medical use. This device is intended in particular for allowing an intradermal injection to be performed.

BACKGROUND OF THE INVENTION

In the following description, the terms “proximal” and “distal” are considered with reference to the direction in which the product is injected.

It is customary to perform an intradermal injection using a traditional syringe, the needle being inserted at a direction forming a slight angle with the skin.

These traditional syringes do not guarantee complete reliability of the injection, nor complete safety against the risk of accidental needlestick injuries which can occur after the injection.

In order to reduce these risks to a minimum, it is important to limit the freedom of action of the end user of such injection devices.

The invention aims to overcome this fundamental problem.

The object of the invention is therefore to make available a device which guarantees complete reliability of the injection and complete safety against the risk of accidental needlestick injuries, by means of limiting the actions of the end user to a minimum.

SUMMARY OF THE INVENTION

The present invention concerns a device for injection of a product, in particular for medical use, comprising:a body receiving a hollow injection needle and a container containing the product to be injected, the needle and container being movable relative to said body between an injection position and a retracted position;means for holding the needle in position, which means normally hold the needle in said injection position, and which means can be released to permit movement of the needle to said retracted position;means for holding the container in position, which means normally hold the container in a position permitting injection, and which means can be released to permit movement of the container to said retracted position;a piston engaged in the container,characterized in that it additionally comprises:first actuating means of means for holding the needle in position,second actuating means of means for holding the container in position,said first and second actuating means making it possible, at the end of the injection, to respectively release the means for holding the needle in position before the release of the means for holding the container in position, or to simultaneously release the means for holding the needle in position and the means for holding the container in position,a container support which is mounted slidably on the body and is displaceable relative to the latter in order to perform the injection, said container being connected to this support and being able to move relative to the latter between a position permitting injection and a retracted position,means for holding the container support in position, which means normally hold the container support in a standby position before the injection and can be released to permit displacement of the container support and to permit injection,means activating the release of the means for holding the container support permitting injection in position.

Before injection, the support is held in a fixed standby position relative to the body. The container is thus connected to the support. The user acts on the means activating the release of the means for holding the support in position. The displacement of the support relative to the body in the distal direction causes the displacement of the container in the same direction. As the needle is also held relative to the body in the injection position, the movement of the container generates a force on the piston which applies a pressure on the liquid. This pressure pushes the liquid contained in the container towards the needle and the patient's skin.

The first actuating means are separate from the second actuating means. Thus, at the end of the injection, said first actuating means cause the release of said means for holding the needle in position whereas, either simultaneously or subsequently, the second actuating means cause the release of said means for holding the container in position, thus making it posible to bring the needle and the container into the retracted position. This retraction guarantees complete safety against the risk of accidental needlestick injuries.

In particular, when the second actuating means cause the release of said means for holding the container in position subsequently to the release of said means for holding the needle in position by the first actuating means, then the chance to retract the needle before the full dose is administered (leakage, misdose, etc. . . ) is reduced.

Advantageously, the means for holding the support in position comprise:a ring mounted in a fixed manner inside the body and in the proximal part of the latter, this ring having at least one transverse tooth at its distal end,at least one hook situated at the proximal end of the support and intended to clip into said tooth,a spring whose distal end bears on a transverse internal step at the distal end of the support, and whose proximal end bears on a transverse wall situated at the distal end of the ring, said spring being in the compressed state when the tooth is clipped into the hook.

Advantageously, the means activating the release of the means for holding the support in position are in the form of a button integral with the tooth of the ring, said button protruding outside the body through a slot formed in the body for this purpose.

Thus, when the end user presses the button, the tooth, which is integral with the button, is deflected in the radial direction towards the axis of the device and frees itself from the hook of the support. As the support is no longer retained on the ring, the spring relaxes, carrying with it the support which moves in the distal direction. As the support is also connected to the container, it carries the latter in the distal direction and permits the injection.

The device according to the invention has the advantage of requiring only a minimal intervention on the part of the end user. The latter only has to press the button of the ring in order to carry out the injection.

Advantageously, the device comprises spring means which, at the end of the injection, bring the needle and the container into the retracted position without any external voluntary intervention.

According to a possible embodiment of the invention, said means for holding the needle in position comprise:a needle-supporting component comprising at least one locking means;at least one tab comprising a locking means able to cooperate with that of said needle-supporting component, this tab being movable radially between a normal, radially inward position, in which said locking means engage so as to hold said needle-supporting component in position relative to said body, and a radially outward position in which a zone of the support moves this tab radially outwards in such a way as to free said lock, which thus frees said needle-supporting component relative to said body.

According to a possible embodiment of the invention, said means for holding the container in position comprise:a flange formed at that end of the container remote from the closed end of this container;engagement means integral with said support and allowing said flange to be connected to the support; andat least one tab comprising said engagement means and able to move in the radial direction of this support, between a radially inward position, in which said engagement means connect said flange to the support, and a radially outward position in which said engagement means are withdrawn radially from this flange, thereby releasing it.

The piston engaged in the container is preferably designed in such a way that, in a first configuration of the piston or relative position of this piston and of this container, it closes the container so as to isolate the product from the outside of this container, and, in a second configuration of the piston or relative position of this piston and of this container, it permits the passage of the product to outside the container. The piston can in particular comprise at least one peripheral zone which, in said first configuration of the piston, is able to bear tightly against the wall of the container, and, in said second configuration of the piston, is able to withdraw under the pressure of the product to be injected, thereby permitting passage of this product.

The piston can also comprise a pierceable zone opposite the proximal end of the needle. The displacement of the container relative to the needle then causes the proximal end of the needle to pierce this pierceable zone of the piston until it comes into communication with the product to be injected and to permit this product to flow through the needle.

The attached figures illustrate, by way of example, a preferred embodiment of the device according to the invention.

DETAILED DESCRIPTION

The figures show a device1for injection of a product, in particular for medical use.

As is shown more particularly inFIGS. 1 and 2, the device1comprises a body2, a hollow injection needle4, an injection-activating spring3, components5to7for mounting the needle4, a spring8for the retraction movement, a container support9, a container10, a piston11, and a ring20, all described in detail below.

The body2is of a generally tubular shape and comprises a circular rib15at its distal end.

The needle4is fixed to the component5. The latter is of a generally cylindrical solid shape and has a groove and a hole which form a flow conduit communicating with the cavity of the needle4.

The component6has a tube-shaped proximal part26in which the component5is tightly received, and it comprises a distal hole to allow the needle4to be engaged through a boss21. The distal face of the boss21forms a surface by which the device1engages on the patient's skin. In the injection position, the needle4preferably extends by a distance of 0.5 mm to 3 mm beyond the surface with which the device1engages on the patient's skin. The part26is intended to be introduced into the container10, as has been mentioned above, and comprises a seal25at its proximal end. This part26thus makes it possible to displace the piston11inside the container10when the support9is displaced relative to the body2, as will be seen later.

The component6also comprises a flange27which can be clipped, by means of a lug27a, into openings provided on four tabs29integral with the component7, said tabs29being arranged in pairs opposite a wall28which extends in the proximal direction from the distal end of the component7, said tabs29being able to deflect circumferentially.

The component7is intended to be inserted tightly into the distal opening of the body2, and a distal flange30which it comprises is positioned in the distal recess delimited by the rib15. This tight engagement permits securing of the component7to the body2.

The component7also comprises an opening delimited by a shoulder31whose diameter is smaller than the diameter of the spring8for initiating retraction.

As is shown inFIG. 3, this shoulder31allows the spring8to be maintained in the compressed state between the proximal face of this shoulder31and the distal face of the flange27when the component6is clipped into the component7.

The component7also comprises, at its proximal end, two bevels32forming ramps. It will be seen fromFIG. 2that the tabs29have internal inclined ramps formed in their proximal parts.

The support9is engaged in the body2and is able to slide relative to the latter.

At its distal end, the support9forms two radially movable tabs39which. are provided with internal projections41(seeFIG. 3) forming stops for receiving a flange45which the container10comprises. This abutment of the flange45against the projections41makes it possible to connect the flange45to the support9in the direction of displacement of the support9, thereby permitting injection.

The support9also forms four walls42situated between the tabs39. As is shown inFIGS. 1 to 3, the tabs39comprise, at their distal ends, internal inclined ramps which are able to cooperate with the ramps of the bevels32at the end of the injection stroke, and the walls42comprise, at their distal ends, external inclined ramps which are able to cooperate with the internal ramps of the tabs29, likewise at the end of the injection stroke.

At its proximal end, the support9comprises at least one hook47intended to clip together with a transverse tooth48situated on the distal end of the ring20. This ring20is mounted in a fixed manner inside the body2in the proximal part of the latter. The ring20also comprises, on its outer face, at least one button49which is integral with the tooth48and which protrudes outside the body2through a slot52formed in the body2for this purpose, as is shown inFIG. 13.

An injection-activating spring3is arranged between the support9and the ring20. As is shown inFIG. 3, the distal end of this spring3bears on a transverse inner step53at the distal end of the support9and its proximal end bears on a transverse wall54situated at the distal end of the ring20. The injection-activating spring3is in the compressed state when the tooth48is clipped into the hook47, as is shown inFIG. 3.

At the opposite end from the flange45, the container10comprises a bottom46. The product to be injected is contained between the piston11and the walls of the container10.

The piston11is made of a flexible material, especially an elastomer. It is of a conical shape and is placed in the container10in such a way that its face having a smaller surface area is directed towards the product to be injected. In this way, as is shown inFIG. 6, it forms a gap50between itself and the wall of the container11. Moreover, the piston11comprises a lateral blind hole51extending a large part of the way through its thickness, from its distal axial face, next to the side wall of the piston11which delimits said gap50. The hole51is of such a shape that it follows this side wall, at least approximately, and thus delimits a peripheral zone extending over part of the periphery of the piston11.

As a comparison ofFIGS. 6 and 7shows, this peripheral zone normally adopts a radially outward position shown inFIG. 6, in which it bears tightly against the wall of the container10, and can assume a radially inward position shown inFIG. 7, into which it withdraws, under the pressure of the product to be injected, as the latter passes between the piston11and the container10, due to the piston11bearing against the product.

In practice, the device1is initially in the storage position shown inFIGS. 3,6and10, in which the lug27aof the flange27is in engagement with the tabs29and the flange45is kept in position by the projections41. In this position, the needle4projects beyond the distal end of the device according to the depth desired for injection, which is an intradermal injection in the example shown. In this position too, the tooth48is clipped into the hook47and the injection-activating spring3is in the compressed state.

The end user presses the button or buttons49projecting from the body2through the slot52. As the button49is integral with the tooth48, the latter deflects radially towards the axis of the device under the pressure exerted on the button49. The tooth48is then freed from the hook47and the injection-activating spring3relaxes, carrying the support9with it in the distal direction. As the support9is connected to the container10on account of the flange45of the container10being held by the tabs39of the support9, the container10is likewise moved in the distal direction.

The displacement of the container10with the support9presses the piston11against the injectable product, which causes the product to flow between the piston11and the container10, as is shown inFIG. 7.

As is shown inFIGS. 4,8and11, on approaching the end-of-injection position the ramps of the tabs39and of the walls42come to bear against, respectively, the ramps of the bevels32and of the tabs29, such that the tabs29are deflected circumferentially and the tabs39are moved towards radially outward positions, in which positions the tabs29and39free, respectively, the lug27aof the flange27and the flange45. The retraction-activating spring8can then relax, which causes simultaneous retreat of the components5and6, and hence of the needle4, and also of the container10on account of the friction of the seal25, towards a retracted position shown inFIGS. 5,9and12. In this position, the distal end of the needle4is situated back from the distal face of the component7and the flange45is situated back from the projections41at the proximal end.

It will be evident from the above that the invention affords a number of crucial improvements to the corresponding devices of the prior art, requiring of the end user only a minimal intervention for performing injection and for retracting the needle, thus making the device completely safe against the risk of accidental needlestick injuries which can occur after injection.

It goes without saying that the invention is not limited to the embodiment described above by way of example, but that instead it encompasses all alternative embodiments coming within the scope of protection defined by the attached claims. In particular, the piston can comprise a pierceable zone located opposite the proximal end of the needle, this proximal end projecting from the proximal end of the component5in which it is held.