Abstract:
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.

Description:
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&#39;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; and   at 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. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is an exploded perspective view in a cross section passing along its axis; 
         FIG. 2  is a perspective view in the assembled state; 
         FIGS. 3 to 5  are cross-sectional views of the device according to the invention, in the storage position, end-of-injection position, and retracted position, respectively; 
         FIG. 6  is a cross-sectional view, along the line XX in  FIG. 3 , of the device in the storage position; 
         FIG. 7  is a partial cross-sectional view of the position of the piston in the injection phase;  FIGS. 8 and 9  are cross-sectional views, along the line XX in  FIG. 3 , of the device in the end-of-injection position and retracted position, respectively; 
         FIGS. 10 to 12  are simplified side views of the device in the storage position, end-of-injection position and retracted position, respectively, showing the release of the means for holding the needle in position; 
         FIG. 13  is a perspective view of the device according to the invention. 
     
    
    
     DETAILED DESCRIPTION 
     The figures show a device  1  for injection of a product, in particular for medical use. 
     As is shown more particularly in  FIGS. 1 and 2 , the device  1  comprises a body  2 , a hollow injection needle  4 , an injection-activating spring  3 , components  5  to  7  for mounting the needle  4 , a spring  8  for the retraction movement, a container support  9 , a container  10 , a piston  11 , and a ring  20 , all described in detail below. 
     The body  2  is of a generally tubular shape and comprises a circular rib  15  at its distal end. 
     The needle  4  is fixed to the component  5 . 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 needle  4 . 
     The component  6  has a tube-shaped proximal part  26  in which the component  5  is tightly received, and it comprises a distal hole to allow the needle  4  to be engaged through a boss  21 . The distal face of the boss  21  forms a surface by which the device  1  engages on the patient&#39;s skin. In the injection position, the needle  4  preferably extends by a distance of 0.5 mm to 3 mm beyond the surface with which the device  1  engages on the patient&#39;s skin. The part  26  is intended to be introduced into the container  10 , as has been mentioned above, and comprises a seal  25  at its proximal end. This part  26  thus makes it possible to displace the piston  11  inside the container  10  when the support  9  is displaced relative to the body  2 , as will be seen later. 
     The component  6  also comprises a flange  27  which can be clipped, by means of a lug  27   a , into openings provided on four tabs  29  integral with the component  7 , said tabs  29  being arranged in pairs opposite a wall  28  which extends in the proximal direction from the distal end of the component  7 , said tabs  29  being able to deflect circumferentially. 
     The component  7  is intended to be inserted tightly into the distal opening of the body  2 , and a distal flange  30  which it comprises is positioned in the distal recess delimited by the rib  15 . This tight engagement permits securing of the component  7  to the body  2 . 
     The component  7  also comprises an opening delimited by a shoulder  31  whose diameter is smaller than the diameter of the spring  8  for initiating retraction. 
     As is shown in  FIG. 3 , this shoulder  31  allows the spring  8  to be maintained in the compressed state between the proximal face of this shoulder  31  and the distal face of the flange  27  when the component  6  is clipped into the component  7 . 
     The component  7  also comprises, at its proximal end, two bevels  32  forming ramps. It will be seen from  FIG. 2  that the tabs  29  have internal inclined ramps formed in their proximal parts. 
     The support  9  is engaged in the body  2  and is able to slide relative to the latter. 
     At its distal end, the support  9  forms two radially movable tabs  39  which. are provided with internal projections  41  (see  FIG. 3 ) forming stops for receiving a flange  45  which the container  10  comprises. This abutment of the flange  45  against the projections  41  makes it possible to connect the flange  45  to the support  9  in the direction of displacement of the support  9 , thereby permitting injection. 
     The support  9  also forms four walls  42  situated between the tabs  39 . As is shown in  FIGS. 1 to 3 , the tabs  39  comprise, at their distal ends, internal inclined ramps which are able to cooperate with the ramps of the bevels  32  at the end of the injection stroke, and the walls  42  comprise, at their distal ends, external inclined ramps which are able to cooperate with the internal ramps of the tabs  29 , likewise at the end of the injection stroke. 
     At its proximal end, the support  9  comprises at least one hook  47  intended to clip together with a transverse tooth  48  situated on the distal end of the ring  20 . This ring  20  is mounted in a fixed manner inside the body  2  in the proximal part of the latter. The ring  20  also comprises, on its outer face, at least one button  49  which is integral with the tooth  48  and which protrudes outside the body  2  through a slot  52  formed in the body  2  for this purpose, as is shown in  FIG. 13 . 
     An injection-activating spring  3  is arranged between the support  9  and the ring  20 . As is shown in  FIG. 3 , the distal end of this spring  3  bears on a transverse inner step  53  at the distal end of the support  9  and its proximal end bears on a transverse wall  54  situated at the distal end of the ring  20 . The injection-activating spring  3  is in the compressed state when the tooth  48  is clipped into the hook  47 , as is shown in  FIG. 3 . 
     At the opposite end from the flange  45 , the container  10  comprises a bottom  46 . The product to be injected is contained between the piston  11  and the walls of the container  10 . 
     The piston  11  is made of a flexible material, especially an elastomer. It is of a conical shape and is placed in the container  10  in 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 in  FIG. 6 , it forms a gap  50  between itself and the wall of the container  11 . Moreover, the piston  11  comprises a lateral blind hole  51  extending a large part of the way through its thickness, from its distal axial face, next to the side wall of the piston  11  which delimits said gap  50 . The hole  51  is 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 piston  11 . 
     As a comparison of  FIGS. 6 and 7  shows, this peripheral zone normally adopts a radially outward position shown in  FIG. 6 , in which it bears tightly against the wall of the container  10 , and can assume a radially inward position shown in  FIG. 7 , into which it withdraws, under the pressure of the product to be injected, as the latter passes between the piston  11  and the container  10 , due to the piston  11  bearing against the product. 
     In practice, the device  1  is initially in the storage position shown in  FIGS. 3 ,  6  and  10 , in which the lug  27   a  of the flange  27  is in engagement with the tabs  29  and the flange  45  is kept in position by the projections  41 . In this position, the needle  4  projects 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 tooth  48  is clipped into the hook  47  and the injection-activating spring  3  is in the compressed state. 
     The end user presses the button or buttons  49  projecting from the body  2  through the slot  52 . As the button  49  is integral with the tooth  48 , the latter deflects radially towards the axis of the device under the pressure exerted on the button  49 . The tooth  48  is then freed from the hook  47  and the injection-activating spring  3  relaxes, carrying the support  9  with it in the distal direction. As the support  9  is connected to the container  10  on account of the flange  45  of the container  10  being held by the tabs  39  of the support  9 , the container  10  is likewise moved in the distal direction. 
     The displacement of the container  10  with the support  9  presses the piston  11  against the injectable product, which causes the product to flow between the piston  11  and the container  10 , as is shown in  FIG. 7 . 
     As is shown in  FIGS. 4 ,  8  and  11 , on approaching the end-of-injection position the ramps of the tabs  39  and of the walls  42  come to bear against, respectively, the ramps of the bevels  32  and of the tabs  29 , such that the tabs  29  are deflected circumferentially and the tabs  39  are moved towards radially outward positions, in which positions the tabs  29  and  39  free, respectively, the lug  27   a  of the flange  27  and the flange  45 . The retraction-activating spring  8  can then relax, which causes simultaneous retreat of the components  5  and  6 , and hence of the needle  4 , and also of the container  10  on account of the friction of the seal  25 , towards a retracted position shown in  FIGS. 5 ,  9  and  12 . In this position, the distal end of the needle  4  is situated back from the distal face of the component  7  and the flange  45  is situated back from the projections  41  at 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 component  5  in which it is held.