Automatic injection device

Abstract

The present disclosure relates to an automatic injection device (1), - a body (10), - a medical container (20) comprising a barrel (24) containing an injectable product, a needle (22) and a distal tip (23) with a stopper (25) in sliding engagement within said barrel, said medical container being slidably disposed within said body (10) between a proximal position and a distal position; - a safety shield (60) slidably mounted within said body (10) between a distal initial position and a proximal second position; - an outer shell (90) surrounding said body (10), said outer shell (90) being distally slidable relative to said body (10); - a plunger rod (40) slidably disposed within said body (10), said plunger rod including a proximal flange (44) releasably locked in a proximal initial position by at least one flexible arm (140) of said body, said plunger rod being movable in a distal direction when said proximal flange is unlocked to engage said stopper (25) with a distal tip (43) of said plunger rod; - a cam (70) cooperating with said safety shield (60) such that translation of said safety shield (60) from said distal safety position to said proximal second position causes said cam (70) to rotate within said body (10) to an unlocked position; - a button (80) slidably mounted on the proximal end of said body (10); in the initial position, the button (80) is prevented from moving distally by the cam (70), and when the cam is in the unlocked position, the button (80) is permitted to move in the distal direction; The outer shell (90) cooperates with the safety shield (60) and the button (80) such that when a user presses the outer shell (90) against a patient's skin to perform an injection, the safety shield moves the cam to the unlocked position to unlock the button, and the outer shell (90) further pushes the unlocked button in the distal direction to deflect the at least one flexible arm (140) of the body outwardly to release the proximal flange (44) of the plunger rod, thereby moving the plunger rod to the injection position.

Description

[Technical field]

[0001] The present invention relates to a medical device for automatically injecting a product in a safe manner, especially in emergency situations. [Background technology]

[0002] Some illnesses require regular injections of drugs or products, for example on a daily basis. To simplify treatment, some autoinjectors are provided to allow patients to administer the injections themselves.

[0003] As the patient is usually not a nurse or someone trained in medical equipment, such an autoinjector must be very easy to use and also prove to be very safe: in particular, the needle insertion must be performed to the correct depth, the correct dose of product must be injected, i.e. a complete injection must be performed, and the injector must be deactivated after use before being discarded.

[0004] Preferably, the needle should not be exposed before or after use to prevent accidental needle stick injuries.

[0005] Another important requirement of these self-injection devices is that they must not be accidentally activated before the patient is ready to perform the injection, and in particular before the device has been correctly applied at the appropriate injection site.

[0006] Some automatic injection devices include a safety shield adapted to cover the needle tip except during an injection, and a button that is pressed by the patient to trigger the injection.

[0007] US Pat. No. 5,399,633 discloses such an automatic injection device.

[0008] Prior to use, the safety shield and needle are covered with a cap and the button is locked to prevent accidental actuation, and the device includes a mechanism configured to unlock the button when the safety shield is fully pressed into the patient's skin.

[0009] An injection therefore requires three actions from the user.

[0010] (1) Removing the cap; (2) pressing the device firmly against the patient's skin to unlock the button; and (3) Pressing the unlocked button to activate the device and trigger an injection.

[0011] However, when drugs must be administered to a patient in an emergency situation, this three-step injection process may be too long or complicated. For example, if a patient suffers from anaphylaxis, adrenaline must be administered very quickly to avoid the patient's death.

[0012] There is therefore a need for an autoinjector device that can be activated in a minimal number of steps without compromising the safety of the device, in particular, as noted above, the device must not be accidentally activated and accidental needle stick injuries must be avoided. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] European Patent No. 2921191 Summary of the Invention

[0014] The present invention meets this need by proposing a device for the automatic injection of a product into an injection site, - The main body, - a medical container comprising a barrel containing an injectable product, a distal tip with an injection needle, and a stopper in sliding engagement within said barrel, said medical container being slidably disposed within said body between a proximal position and a distal position; - a safety shield slidably mounted within said body between a distal initial position and a proximal second position; - an outer shell surrounding said body, said outer shell being distally slidable relative to said body; and - a plunger rod slidably disposed within the body, the plunger rod including a proximal flange releasably locked in a proximal initial position by at least one flexible arm of the body, the plunger rod being movable in a distal direction when the proximal flange is unlocked to engage a distal tip of the plunger rod and the stopper; - a cam cooperating with the safety shield such that translation of the safety shield from the distal safety position to the proximal second position rotates the cam within the body to an unlocked position; a button slidably mounted on the proximal end of the body; in the initial position, the button is prevented from moving distally by the cam, and when the cam is in the unlocked position, the button is allowed to move in the distal direction; The outer shell cooperates with the safety shield and the button such that when a user presses the outer shell against a patient's skin to perform an injection, the safety shield moves the cam to the unlocked position to unlock the button, and the outer shell further presses the unlocked button in the distal direction to deflect the at least one flexible arm of the body outwardly to release the proximal flange of the plunger rod, thereby allowing the plunger rod to move to the injection position.

[0015] Thanks to the cooperation between the cam and the medical container, and the outer shell and button, only two actions are required from the user to fully perform the injection: (1) removing the cap and (2) pressing the safety shield against the patient's skin.

[0016] Thus, the ergonomics of the device are improved, which is particularly beneficial in emergency situations, as it simplifies operation of the device and reduces the time required to inject the entire dose into the patient.

[0017] As used herein, the distal end of a component or device shall be understood to mean the end furthest from the user's hand, and the proximal end shall be understood to mean the end closest to the user's hand. Similarly, as used herein, the distal direction shall be understood to mean the direction of injection, and the proximal direction shall be understood to mean the direction opposite to the direction of injection.

[0018] As used herein, the term "axial" refers to a direction parallel to the injection direction (which also corresponds to the longitudinal axis of the injection device) and the term "radial" refers to a direction perpendicular to the injection direction.

[0019] In a preferred embodiment, alone or, more appropriately, in combination, - each flexible arm includes an inclined inner surface tapering inwardly in a distal direction and at least one plunger retainer disposed distally from said inclined surface, a proximal flange of the plunger rod abutting said at least one retainer in said initial position.

[0020] - the button includes at least one inner protrusion extending in the distal direction, the at least one protrusion being spaced proximally from the inclined surface of each flexible arm in the initial position, and in the actuated position the at least one inner protrusion engages the respective inclined surface to deflect the flexible arms outwardly.

[0021] - the button includes at least one leg extending distally and the cam includes a proximal end with at least one recess, in the initial position the button is locked by the cam by abutment of each leg with the proximal end of the cam, the legs being angularly spaced from each recess, and in the unlocked position of the cam each leg faces a respective recess thereby allowing the button to move in the distal direction relative to the cam.

[0022] - The outer shell is made of UV-resistant material.

[0023] - said outer shell comprises at least one window allowing visualization of the internal components of said injection device.

[0024] - the outer shell comprises at least one proximal window making it possible to visualize the injectable product in its initial position and at least one distal window making it possible to visualize the stopper of the medical container at the end of the injection.

[0025] the injection device further comprises a cap removably connected to a distal end of the outer shell, the cap comprising two rigid arms extending in the proximal direction.

[0026] the rigid arm covers the at least one window when the cap is connected to the outer shell.

[0027] The safety shield includes at least one lug received in the first groove of each of the cams such that movement of the safety shield in a proximal direction rotates the cams.

[0028] - the first groove presents an inclined first branch and an axial second branch connected to the first branch at its proximal end, so that in the initial position, the lug is located at the distal end of the first branch and moves towards the proximal end of the first branch when the safety shield moves from the initial position to the second position.

[0029] The plunger rod is biased in a distal direction by a first spring.

[0030] The safety shield is biased in a distal direction by a second spring.

[0031] - the injection device further comprises a ring supporting the medical container, the ring including at least one finger protruding radially outward, the cam further comprising at least one second groove receiving each of the at least one finger, the at least one second groove including a proximal portion, a distal portion and a sloped portion connecting the proximal portion to the distal portion, the ring being locked at the proximal end of the groove and moving along the sloped portion to the distal portion when the plunger rod pushes the medical container from the initial position to the injection position.

[0032] - said at least one finger engages an axial groove in said body;

[0033] an axial distance between the proximal and distal portions of the second groove is equal to a penetration depth of the needle within the patient's body.

[0034] the distal translation of the ring rotates the cam such that the lug of the safety shield engages the second branch of the first groove of the cam. [Brief description of the drawings]

[0035] Further features and advantages of the present invention will be disclosed in the following detailed description, taken in conjunction with the accompanying drawings. [Figure 1] FIG. 1 is a perspective view of an injection device. [Diagram 2] FIG. 2 is an exploded view of the button, body, and cap of the injection device. [Diagram 3] FIG. 3 is an exploded view of the medical container and needle shield of the injection device. [Figure 4]FIG. 4 is an exploded view of the plunger rod and medical container. [Diagram 5] FIG. 5 is a perspective view of the cap and needle shield. [Figure 6] FIG. 6 is a perspective view of a medical container and a support ring. [Figure 7] FIG. 7 is a perspective view of the safety shield. [Figure 8] FIG. 8 is a perspective view of the cam. [Figure 9] FIG. 9 is a perspective view of the safety shield, cam and ring assembly. [Figure 10] FIG. 10 is an exploded view of the button and cam. [Figure 11] FIG. 11 is an exploded view of the outer shell. [Figure 12] FIG. 12 is a partial perspective view of the outer shell. [Figure 13] FIG. 13 is a cross-sectional view of the injection device prior to use. [Figure 14] FIG. 14 is a cross-sectional view of the injection device in the initial position. [Figure 15] FIG. 15 is a cross-sectional view of the injection device in an unlocked position. [Figure 16] FIG. 16 is a cross-sectional view of the injection device at the end of an injection. [Figure 17] FIG. 17 shows a left to right side view of the injection device before use, in the initial position, and at the end of the injection. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] Unless otherwise stated, the components of the injection device are depicted in their initial positions prior to using the injection device. However, as described below, some of the components are movable translationally and / or rotationally relative to one another to perform the injection. Thus, the description refers not only to the initial positions of the components, but also to one or more operating positions or stages reached during the injection process.

[0037] In summary, prior to use, the body of the injection device is closed by a cap which protects the interior of the injection device from the external environment.

[0038] In the first step, the cap is removed, so that the injection device is in an initial position, in which the needle and the medical container containing the injectable product are housed in the body of the injection device, and exposure of the needle and injection of the product are prevented by the fact that the plunger rod is translationally locked in the body.

[0039] In a second step, to perform the injection, the user handles the outer shell surrounding the body of the injection device and presses the outer shell to apply the safety shield to the patient's skin at the injection site. The safety shield is thus translated in a proximal direction, which causes a cam coupled to the safety shield to rotate until it unlocks the button of the injection device. As a result, the button pressed by the outer shell can be translated in a distal direction relative to the body to release the plunger rod. As a result, the medical container engaging the stopper is translated in a distal direction by the plunger rod, thereby allowing the needle to penetrate the patient's skin at the appropriate injection depth. Furthermore, the distal movement of the stopper in the medical container expels the product from the medical container into the patient's body.

[0040] FIG. 1 shows a perspective view of a device for automatic injection, generally designated by the reference numeral 1, according to one embodiment of the present disclosure.

[0041] The device 1 comprises a housing 10 consisting of an upper body 11 and a lower body 12 which may be rigidly connected to each other.

[0042] The connection of the upper and lower bodies may be a snap-fit ​​connection, a threaded connection, a bayonet connection, or other means of connecting the two parts together, whether or not releasable. If the device is of the disposable type, the means for connecting the upper body to the lower body shall be inaccessible to the user.

[0043] A medical container 20 , such as a syringe, for example, is received in at least one of the upper body 11 and the lower body 12 .

[0044] As shown in FIG. 3, the medical container 20 has a radial flange 21 defined at an open proximal end and an injection needle 22 at a substantially closed distal end 23. A sidewall extends between the proximal and distal ends and defines a barrel 24 sized and shaped to contain a quantity of the injectable product. The injection needle 22 may be fixed to the distal end 23 or may be removable therefrom as a matter of design choice. The injection needle 22 is in fluid communication with the barrel 24 and provides an exit port of the medical container 20 for the product.

[0045] A needle shield 30 is provided at the distal end of the medical container 20 to cover and protect the needle 22 prior to use of the device 1. The needle shield 30 also provides a means of sealing the distal end 23 of the medical container prior to use. To that end, the needle shield 30 may include an inner elastomeric shield 31 that sealingly engages the distal end of the medical container, and an outer rigid cap 32 that surrounds the inner shield.

[0046] Prior to use (see Figures 5 and 13), cap 13 engages with outer rigid cap 32 such that removal of cap 13 simultaneously removes inner elastomeric shield 31 and outer rigid cap 32 from the distal tip of the medical container.

[0047] A stopper 25 is provided in the container 20 and is slidable within the barrel 24. Distal movement of the stopper causes product to be expelled from said medical container 20 through the needle 22 during injection of the product into a patient. The stopper is typically made of an elastomeric material. The inner surface of the barrel and / or the outer surface of the stopper may be lubricated to reduce the sliding force of the stopper within the barrel.

[0048] A plunger rod 40 is received within the proximal portion of the upper body 11 for moving a stopper relative to the medical container 20, as will be described below.

[0049] 4, plunger rod 40 includes a shaft 41 with a distal flange 42 and a distal tip 43 adapted to engage a stopper at an injection location. Shaft 41 also includes a proximal flange 44. Shaft 41 may include one or more axial ribs designed to increase its stiffness.

[0050] Returning to Figures 1 and 2, the upper body 11 has a generally cylindrical shape and is open at both ends. The distal end is connected to the lower body 12. The upper body further comprises an inner cylinder 14 for receiving the plunger rod 40. The inner cylinder 14 comprises an axial wall parallel to the outer wall of the upper body and connected to said outer wall by a radial wall. The inner cylinder 14 has an open distal end and a proximal end with at least one flexible arm 140 comprising an inclined inner surface 16 tapering inwardly in a distal direction and at least one plunger retainer 17 disposed distally from said inclined surface 16. Preferably, the proximal end comprises two flexible arms 140 diametrically opposed to each other, or two pairs of diametrically opposed flexible arms, adjacent arms spaced at an angle of 90°. For example, each plunger retainer 17 is in the form of a clip extending radially inwardly and comprises a proximal face perpendicular to the injection direction that engages with a distal face of the proximal flange 44 of the plunger rod in the initial position. Thus, in the initial position, the plunger rod 40 is prevented from moving distally by the plunger retainer 17 (see FIG. 14). As will be explained in more detail below, the flexible arms 140 are designed to be able to deflect outwardly when a force is applied to the ramp surface 16 in the distal direction.

[0051] Button 80 is slidably mounted to the proximal portion of upper body 11 .

[0052] The button is prevented from moving proximally by a clip 85 that engages with upper body 11, but is able to slide distally.

[0053] The button substantially surrounds the proximal end of the inner cylinder 14 .

[0054] As shown in FIG. 10, button 80 includes an axial skirt 81 having a generally cylindrical shape that is open at its distal end and closed at its proximal end.

[0055] The button includes at least one leg 83 extending distally from the skirt 81. Preferably, the button includes two legs 83 diametrically opposed to one another.

[0056] The proximal end of the button includes at least one inner protrusion 84 extending distally towards the flexible arms 140. In some embodiments, the protrusion may form a continuous annular rib. In other embodiments, at least two separate protrusions 84 are provided, each in angular alignment with a flexible arm 140, with the number of protrusions 84 equal to the number of flexible arms 140. In the initial position, the at least one protrusion 84 is spaced proximally from the angled surface 16 of each flexible arm.

[0057] A first spring 49 (best seen in Figures 13-16) is disposed around the shaft 41 of the plunger rod, with a distal end of the spring 49 bearing against the proximal face of the distal flange 42 and a proximal end of the spring 49 bearing against the distal face of the plunger retainer 17. In the initial position (see Figure 14), the spring is in compression. As a result, the spring 49 biases the plunger rod 40 in a distal direction. However, in the initial position, as described above, the plunger rod is locked by the plunger retainer 17 and is therefore prevented from translating in the distal direction.

[0058] The medical container 20 is attached to the support ring 50. As shown in FIG. 6, the ring may include a distal rigid portion 51 and a proximal elastomeric portion 52. The barrel of the medical container is inserted into the support ring 50 such that the proximal flange 21 contacts the proximal face of the proximal elastomeric portion 52. The medical container may be maintained in a fixed position relative to the ring by frictional engagement between the elastomeric portion 52 and the barrel.

[0059] The ring 50 comprises at least one finger 53 projecting radially from the rigid portion 51. Preferably, the ring comprises two fingers 53 diametrically opposed to one another.

[0060] The lower body forms a housing that at least partially receives the medical container 20 and the ring 50. As will appear later, the medical container 20 is movable relative to the lower body between an initial position in which the tip of the needle does not extend beyond the distal end of the lower body and an injection position spaced distally relative to the initial position in which the tip of the needle extends beyond the distal end of the lower body and is exposed a predetermined length.

[0061] 1 and 2, the lower body has a generally cylindrical shape and is open at both ends. The lower body 12 has a distal portion 12b and a proximal portion 12a, with the diameter of the proximal portion 12a being larger than the diameter of the distal portion 12b. The proximal portion 12a and the distal portion 12b are connected by a radial wall 12c. The proximal surface of the radial wall 12c forms an abutment surface for the ring 50.

[0062] The lower body comprises at least one axial groove 15 for receiving a respective finger 53 of the ring 50. Preferably, the lower body has two axial grooves 15 diametrically opposite each other and the ring has two fingers, each of which is received in a respective axial groove. As will be explained in more detail below, such axial groove serves as a guide for the axial movement of the ring (and the container) relative to the lower body. Advantageously, said groove is located in the proximal part of the lower body 12, which is covered by the upper body 11, so that the groove 15 and the fingers 53 are not accessible by the user from outside the injection device.

[0063] The injection device also includes a safety shield 60 that is at least partially received within the distal portion of the lower body. As shown in Figure 7, the safety shield 60 includes two opposing proximally extending tongues 61. Each tongue 61 includes a lug 62 extending radially outwardly.

[0064] The distal end of the safety shield 60 is advantageously provided with a radial flange 63 forming a bearing surface for application of the injection device to the patient's skin, the width of the flange being selected to distribute the compressive force over a sufficiently large surface area so as not to injure the patient.

[0065] The safety shield is coupled to a cam 70 that is pivotally mounted to the lower body 12 .

[0066] As shown in Figures 8 and 9, the cam 70 has a generally cylindrical shape and is open at both ends.

[0067] The cam 70 presents at least one first groove 71, preferably two first grooves diametrically opposite each other.

[0068] Each primary groove 71 comprises an inclined (i.e. non-axial) first branch 71a and an axial second branch 71b connected to the first branch at the proximal end of both branches 71a, 71b. Otherwise, each primary groove has the shape of the number "1".

[0069] Each lug 62 of the safety shield slidably engages a respective first groove 71 in the cam 70 .

[0070] In the initial position, the lug 62 is located at the distal end of the first branch 71a and moves towards the proximal end of the first branch 71a as the safety shield 60 moves from the initial position to the injection position. Such proximal movement of the safety shield 60 consequently rotates the cam according to an angle depending on the inclination of the first branch 71a and the stroke of the lug 62.

[0071] The second spring 65 is disposed between the proximal end of the rigid portion of the ring 50 and the flange 64 of the safety shield. In an initial position, the second spring 65 may be in a relaxed state, but proximal movement of the safety shield 60 compresses the second spring 65. As a result, when the user releases the pressure applied to the injection device, the second spring 65 biases the safety shield 60 in a distal direction.

[0072] The cam 70 further comprises at least one second groove 72 (preferably two second grooves 72 diametrically opposite each other). Each second groove 72 comprises a proximal portion 72a extending perpendicular to the injection direction, a distal portion 72c parallel to the proximal portion, and an angled (i.e., non-axial) portion 72b connecting the proximal portion 72a to the distal portion 72c. Otherwise, the proximal and distal portions 72a and 72c of each second groove are spaced apart both axially and angularly. The axial distance between the proximal and distal portions 72a and 72c of the second groove 72 is equal to the penetration depth of the needle in the patient's body.

[0073] The ring 50 is at least partially received within the cam with each finger 53 of the ring in sliding engagement within a respective second groove 72 .

[0074] In the initial position, each finger 53 of the ring is in a proximal portion 72 a of a respective second groove 72 .

[0075] The cam 70 further comprises at least one recess 73 (preferably two recesses 73 diametrically opposed to one another) formed in the proximal end of the cam. In the initial position, each leg 83 of the button is in substantial abutment with the proximal end of the cam and is angularly spaced from the recess 73 (see FIG. 10 ). As a result, in this initial position, the cam 70 prevents distal translation of the button 80. Even when the legs 83 are not in contact with the proximal end of the cam, the distance between the distal end of the legs 83 and the proximal end of the cam 70 is sufficiently small so that distal translation of the button 80 does not allow the inner projection 84 to deflect the flexible arm 140, thereby releasing the plunger rod 40.

[0076] When the cam 70 is pivoted by the movement of the safety shield 60 in the proximal direction along the first branch 71a of the first groove of the cam (as described above), each recess 73 is pivoted relative to a respective leg 83 of the button. The first groove 71 and the recesses 73 are designed such that when the lug 62 reaches the connection between the first branch 71a and the second branch 71b of the first groove 71 (corresponding to the second position of the safety shield), the leg 83 of the button faces the respective recess 73 (corresponding to the unlocked position of the cam). However, said rotation of the cam 70 does not cause any movement of the ring 50.

[0077] An outer shell 90 is provided around and completely encloses the body 10. Advantageously, the outer shell may be formed of a plastic material that is opaque to UV light to protect the injectable product. For example, the outer shell may be made of polycarbonate.

[0078] As shown in Figures 11 and 12, the outer shell 90 may include first and second half shells 91, 92 that are substantially symmetrical to each other. The half shells are rigidly connected to each other, for example by a snap-fit ​​connection, or any other suitable means. The outer shell has an outer shape adapted to be held in a user's hand. In general, the outer shell 90 is intended to be gripped by the palm and fingers of a user.

[0079] The outer shell has a closed proximal end and an open distal end.

[0080] The outer shell 90 includes a cap 93 removably connected to the first and second half shells 91, 92 for closing the distal end prior to use of the injection device.

[0081] Cap 93 is rigidly coupled to cap 13 such that when cap 93 is removed, cap 13 and needle shield 30 are also removed. In some embodiments (not shown), cap 13 may be integral with cap 93 so as to form a single piece.

[0082] The cap 93 comprises two arms 94 extending in the proximal direction. Each arm 94 may include on its outer surface a number of parallel ribs 95 substantially perpendicular to the injection direction. Said ribs 95 may, on the one hand, form a gripping portion allowing the user to pull the cap in the distal direction and, on the other hand, increase the stiffness of the arms so as to avoid twisting of the cap and needle shield during removal.

[0083] Each half shell 91, 92 advantageously includes a proximal window 96 and a distal window 97. Prior to use of the injection device, the windows 96, 97 are masked by arms 94 of cap 93. When cap 93 is removed, the windows 96, 97 function as visual indicators by allowing a user to view the internal components of the injection device, as will be described in more detail below.

[0084] Outer shell 90 is slidably mounted relative to body 10. The inner surface of the proximal end of the outer shell contacts the proximal face of button 80.

[0085] In the initial position, the distal end of the outer shell is disposed proximally relative to the distal end of the lower body 12. In said initial position, the button projections 84 are spaced proximally from the angled surfaces 16 of each flexible arm of the inner cylinder of the body 10.

[0086] Next, the function of the injection device 1 will be described.

[0087] The injection device is provided to the user ready to use with a cap closing the distal end of the outer shell.

[0088] The medical container is filled with a predetermined dose of the injectable product, preferably a single dose, thus providing a one-time use or disposable injection device.

[0089] Prior to use, the user removes the cap and needle shield without rotating the needle shield and places the safety shield against the skin of a patient at the injection site, which may be the user or another person.

[0090] When the device is pressed against the patient's skin, the safety shield moves proximally into the lower body.

[0091] Because of the safety features described above, the user cannot activate the device (i.e., move the container from its initial position to its injection position and cause the plunger to push the stopper within the barrel) until the safety shield has moved a predetermined distance in a proximal direction to allow the cam to unlock the button.

[0092] Once the device is pressed against the patient's skin via the outer shell (and the safety shield is moved from its initial proximal position), the device will automatically activate and begin injection until the button is unlocked.

[0093] The unlocking of this button allows the outer shell to be pushed distally, releasing the plunger rod and therefore the stopper, said movement of the stopper thus moving the entire medical container distally from its initial position to its injection position, which also causes the needle to penetrate the patient's skin.

[0094] The plunger rod then pushes the stopper distally, still within the barrel, which automatically expels the injectable product from the container and onto the patient's skin.

[0095] It should be noted that once the button is unlocked, the unlocking of the plunger rod, the movement of the stopper, and the movement of the medical container occur during successive injection stages without further action from the user. In addition, the second position of the safety shield and the unlocked position of the cam are not stable positions, but simply intermediate (temporary) positions reached during triggering of the injection device.

[0096] Once the injection is complete, the user removes the device from the injection site and the safety shield automatically extends from the lower body to cover the now contaminated needle tip. Advantageously, the safety shield automatically extends over the needle tip even if the user removes the device from the injection site before the injection is completed. Once the injection device is removed from the injection site and the safety shield extends over the needle tip, the shield is locked in place and cannot thereafter be moved from its proximal locked position to expose the needle tip. Thus, the used injection device is presented safely for handling and disposal.

[0097] Thus, the trigger of the injection device requires only one action from the user after the cap has been removed.

[0098] Referring to the drawings, Fig. 13 shows the injection device before use, and Fig. 14 shows the injection device in an initial position. When a user applies the injection device to an injection site by the bearing surface 63 of the safety shield 60 (the user holds the injection device via the outer shell 90), a distal force is applied to the lower body 12, which causes the safety shield 60 to move relative to said lower body from an initial position to a second position where the cam unlocks the button, the second position of the safety shield being located proximally relative to said initial position.

[0099] During this proximal movement of the safety shield 60 to its second position, each lug 62 moves along the angled branch 71a of the cam 70, thereby rotating the cam 70 into connection with the axial branch 71b, which corresponds to the unlocked position of the cam.

[0100] If the user releases the pressure before reaching the second position, the compressed second spring 65 will cause the safety shield to return to the distal position to protect the needle.

[0101] In the unlocked position of the cam, each leg 83 of button 80 faces a respective recess 73 in the proximal end of the cam. As a result, if a user maintains pressure on outer shell 90, the outer shell will move button 80 distally relative to body 10 until legs 83 abut the proximal faces of recesses 73 (see FIG. 15 ).

[0102] The axial dimensions of the recess 73 and the inner projection 84 are selected such that during this distal movement of the button, the inner projection 84 of the button engages the ramp surface 16, which causes each flexible arm of the inner cylinder 14 to deflect outwardly, thus disengaging the plunger retainer 17 from the proximal flange 44 of the plunger rod.

[0103] As a result, plunger rod 40 moves distally under the distal force of spring 49 .

[0104] The force of the first spring 49 is greater than the force of the second spring 65. In particular, the force of the second spring 65 must be low enough to allow the safety shield 60 to move proximally to place the cam in the unlocked position so that the outer shell presses a button that releases the first spring 49.

[0105] The distal end 43 of the plunger rod 40 engages the stopper and urges it distally. The stopper, in frictional engagement with the barrel, thus displaces the entire medical container distally.

[0106] As the medical container is supported by the ring 50, the ring 50 translates distally together with the medical container. During said translation, the fingers 53 of the ring 50 move within the second grooves 72 of the cam. More precisely, each finger 53 engages with the inclined portion 72b of the respective second groove 72 until the finger 53 reaches the distal portion 72c of the second groove, which prevents further distal movement of the ring 50 and the medical container. Said translation of the ring 50 causes the cam 70 to rotate further, thereby allowing the lug 62 to engage with the second branch 71b of the first groove 71.

[0107] Thus, the medical container has reached its injection position. In this position, the needle protrudes from the distal end of the lower body 12 and penetrates the patient's skin. As mentioned above, the axial stroke of the finger 53 between the proximal portion 72a and the distal portion 72c of the second groove 72 of the cam 70 defines the penetration depth of the needle. This ensures that the product is injected to the appropriate depth between the patient's body.

[0108] The plunger rod continues to push against the stopper until it reaches the distal end of the barrel, expelling the product from the barrel through the needle (see FIG. 16).

[0109] The windows 96, 97 formed in the half shells make it possible to visualize the position of the internal components of the injection device at different stages of the injection process. For example, in the initial position (center of FIG. 17), the user can visually inspect the product for injection through the proximal window 97 (the distal window 96 is blocked by the lower body 12). In the injection position, the distal window 96 is unobstructed thanks to the relative movement of the outer shell and the lower body 12. Thus, the user can visualize the stopper through the distal window 96 when the injection is completed (right side of FIG. 17).

[0110] Once the injection is complete, the user withdraws the injection device from the patient's skin.

[0111] This withdrawal causes the second spring 65 to urge the safety shield 60 distally and the lug 62 to slide within the second branch 71b of the first groove 71 of the cam 70 to a final position where the safety shield covers and protects the needle. When in said final position, the safety shield is locked against proximal movement, thereby preventing unintended access to a contaminated needle.

[0112] The injection device is therefore very easy to use even in an emergency and very safe as it prevents accidental needle stick injuries even if the device is removed from the injection site before injection of the product is actually completed.

Claims

1. An automatic injection device (1), comprising: a body (10), a medical container (20) comprising a barrel (24) containing an injectable product and a distal tip (23) with an injection needle (22) and a stopper (25) in sliding engagement within said barrel, said medical container (20) being slidably arranged within said body (10) between a proximal position and a distal position; a safety shield (60) slidably mounted within said body (10) between a distal initial position and a proximal second position; an outer shell (90) surrounding said body (10), said outer shell (90) being slidable in the distal direction relative to said body (10); a plunger rod (40) slidably disposed within said body (10), said plunger rod including a proximal flange (44) releasably locked in a proximal initial position by at least one flexible arm (140) of said body, said plunger rod being movable in a distal direction when said proximal flange is unlocked to engage said stopper (25) with a distal tip (43) of said plunger rod; a cam (70) cooperating with said safety shield (60) such that translating said safety shield (60) from said distal safety position to said proximal second position causes said cam (70) to rotate within said body (10) to an unlocked position; a button (80) slidably mounted on the proximal end of said body (10); Equipped with In the initial position, the button (80) is prevented from moving distally by the cam (70), and when the cam is in the unlocked position, the button (80) is allowed to move in the distal direction; The outer shell (90) cooperates with the safety shield (60) and the button (80) so that when a user presses the outer shell (90) against a patient's skin to perform an injection, the safety shield moves the cam to the unlocked position to unlock the button, and the outer shell (90) further presses the unlocked button in the distal direction to deflect the at least one flexible arm (140) of the body outward to release the proximal flange (44) of the plunger rod, thereby moving the plunger rod to the injection position.

2. 2. The automatic injection device of claim 1, wherein each flexible arm (140) includes an inclined inner surface (16) tapering inward in the distal direction and at least one plunger retainer (17) disposed distally from the inclined surface (16), and the proximal flange (44) of the plunger rod abuts the at least one retainer (17) in the initial position.

3. 3. The automatic injection device of claim 2, wherein the button (80) includes at least one inner protrusion (84) extending in the distal direction, the at least one protrusion (84) being spaced proximally from the inclined surface (16) of each flexible arm (140) in the initial position, and the at least one inner protrusion engages with the respective inclined surface (16) to deflect the flexible arms (140) outward in the activated position.

4. 2. The automatic injection device of claim 1, wherein the button (80) includes at least one leg (83) extending distally, the cam (70) includes a proximal end with at least one recess (73), and in the initial position, the button (80) is locked by the cam (70) by abutment of each leg (83) with the proximal end of the cam (70), the legs (83) being angularly spaced from each recess (73), and in the unlocked position of the cam, each leg (83) faces a respective recess (73), thereby allowing the button (80) to move in the distal direction relative to the cam (70).

5. 10. The automatic injection device of claim 1, wherein the outer shell is made of a material that is opaque to UV light.

6. 2. The automatic injection device of claim 1, wherein the outer shell (90) comprises at least one window (96, 97) that allows visualization of the internal components of the injection device.

7. 7. The automatic injection device of claim 6, wherein the outer shell comprises at least one proximal window (97) that allows visualization of the injectable product in the initial position and at least one distal window (96) that allows visualization of the stopper (25) of the medical container at the end of the injection.

8. 8. The automatic injection device of claim 7, further comprising a cap (93) removably connected to the distal end of the outer shell (90), the cap (93) comprising two rigid arms (94) extending in the proximal direction.

9. An automatic injection device as described in claim 8, wherein the outer shell (90) has at least one window (96, 97) that allows the internal components of the injection device to be visualized, and the rigid arm (94) covers the at least one window (96, 97) when the cap (93) is connected to the outer shell (90).

10. 2. The automatic injection device of claim 1, wherein the safety shield includes at least one lug received in a first groove of each of the cams such that proximal movement of the safety shield rotates the cams.

11. 11. The automatic injection device of claim 10, wherein the first groove (71) presents an inclined first branch (71a) and an axial second branch (71b) connected to the first branch at its proximal end, such that in the initial position, the lug (62) is located at the distal end of the first branch (71a) and moves toward the proximal end of the first branch when the safety shield (60) moves from the initial position to the second position.

12. 2. The automatic injection device of claim 1, wherein the plunger rod (40) is biased in the distal direction by a first spring (49).

13. 2. The automatic injection device of claim 1, wherein the safety shield (60) is biased in the distal direction by a second spring (65).

14. 12. The automatic injection device of claim 11, further comprising a ring (50) supporting the medical container (20), the ring including at least one finger (53) protruding radially outward, the cam (70) further including at least one second groove (72) for receiving each of the at least one finger (53), the at least one second groove (72) including a proximal portion (72a), a distal portion (72c), and a sloped portion (72b) connecting the proximal portion (72a) to the distal portion (72c), the ring (50) being locked at the proximal end of the groove (72) and moving along the sloped portion (72c) to the distal portion (72b) when the plunger rod pushes the medical container from the initial position to the injection position.

15. 15. The automatic injection device of claim 14, wherein the at least one finger (53) engages an axial groove (15) in the body.

16. 15. The automatic injection device of claim 14, wherein the axial distance between the proximal portion (72a) and the distal portion (72c) of the second groove (72) is equal to the penetration depth of the needle (22) within the patient's body.

17. 15. The automatic injection device of claim 14, wherein the distal translation of the ring rotates the cam so that the lug of the safety shield engages with the second branch of the first groove of the cam.

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