Injection device with extraction mechanism and associated processes

Abstract

The present invention relates to an injection device with an extraction mechanism and related processes. The injection device (10) comprises: - a needle support (24); - an injection needle (22) integrated with the needle support and having a free end (28) arranged away from the needle support; and - a needle extraction mechanism (50) comprising a base (52) connected to the needle support, and a plunger (54) movable relative to the base between a needle use position and a needle extraction position. The base (52) is movable relative to the needle support between an inactive position of the extraction mechanism and an active position of the extraction mechanism. The plunger (54) comprises an outer member and an inner member movable relative to the outer member from a retracted plunger configuration to a deployed plunger configuration, the length of the plunger in the deployed plunger configuration being greater than in the retracted configuration.

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit to French patent application No. 2102784, filed with the French Patent Office on March 19, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to an injection device, which includes:

[0004] - Needle support component;

[0005] - An injection needle, integrated with a needle support and having a free end disposed away from the needle support; and

[0006] - A mechanism for extracting an injection needle, the mechanism including a base connected to a needle support and a plunger movable relative to the base between a needle use position and a needle extraction position, the base being movable relative to the needle support between a non-active position and an active position of the extraction mechanism.

[0007] The present invention also relates to the preparation process and injection method of such a device. Background Technology

[0008] This device is used to treat certain conditions that require regular injections of liquid medication directly into the patient's organs.

[0009] For this purpose, a subcutaneous, permanently implantable chamber is known in the patient's chest. This chamber extends from a tube that passes through a support and continues into an organ where a drug dose will be delivered. The implantable chamber has a reservoir with a perforated cap along its skin-contacting surface.

[0010] To administer the drug dose, the device's needle is inserted through the patient's skin into an implantable chamber, and the drug dose is injected into the chamber through the needle.

[0011] To remove the needle from the implantable chamber, the practitioner grasps the device holder and pulls the needle out of the chamber.

[0012] However, because the membrane of the implantable cavity is relatively rigid, significant tension must be applied to the needle in order to remove it.

[0013] To prevent patients from experiencing forces exerted on the skin by the implantable chamber during needle removal, it is known to use an injection device equipped with an in-situ extraction mechanism as described in FR-2869806.

[0014] This device is equipped with a mechanical extraction mechanism mounted on the needle support of the injection device, including a plunger, which allows the practitioner to easily extract the needle in a continuous and safe manner. For this purpose, the needle, held by a retainer, is gradually swallowed into the plunger during extraction.

[0015] The extraction mechanism is hinged to the needle support so that it can be extended along the patient's body when not in use, thus reducing the size of the extraction device. To minimize movement of the extraction mechanism, it is positioned in the extended position via a flexible interlocking mechanism.

[0016] The device can be further improved. The extraction device has a large footprint, even in the extended position, and its footprint should be reduced. The bulky device is more likely to cause manipulation errors, such as accidental impacts to the device, which can cause pain to the patient due to the needle being inserted into his or her skin.

[0017] In addition, disengaging the flexible interlocking mechanism to retrieve the needle when it is inserted into the patient's body may cause uncomfortable shaking. Summary of the Invention

[0018] Therefore, the object of the present invention is to provide an injection device that is less bulky and more comfortable for patients to operate.

[0019] Therefore, the object of the present invention is to provide an injection device of the above type, characterized in that the plunger includes an outer component and an inner component, the inner component being movable relative to the outer component from a plunger retracted configuration to a plunger extended configuration, the length of the plunger in the extended configuration being greater than its length in the retracted configuration.

[0020] According to a particular embodiment, the device according to the invention, individually or in any technically feasible combination, includes one or more of the following features:

[0021] - The internal components can be slidably installed in the internal channels of the external components;

[0022] - The plunger includes a flexible interlocking mechanism that is adapted to lock the internal component relative to the external component when the plunger is deployed;

[0023] - The flexible interlocking mechanism includes at least one snap-in tab held by an internal or external member; and at least one housing defined by another of the internal or external members; the snap-in tab having teeth received in the housing when the plunger is deployed.

[0024] – The housing or housings are located near the first end of another of the internal or external components so as to receive one of the teeth when the plunger is deployed. The snap-fit ​​mechanism also includes at least one second housing located near the second end of another of the internal or external components so as to receive the teeth when the plunger is retracted.

[0025] - The flexible interlocking mechanism includes at least one ramp that extends above another of the internal or external components, the ramp defining one of the housings at its upper end, and a snap-fit ​​tab supported on the ramp when the plunger moves from the retracted configuration to the deployed configuration.

[0026] - The flexible interlocking mechanism is suitable for temporarily holding the internal component relative to the external component when the plunger is in the retracted configuration;

[0027] - In the unfolded configuration, the plunger defines the internal space for receiving the needle;

[0028] - The device includes a component for temporarily fixing the base in an inactive position, which is active when the plunger is in a retracted configuration and deactivated when the plunger moves from the retracted configuration to the deployed configuration.

[0029] - The temporary fixing assembly includes a first slot extending on an inner member and a second slot extending on an outer member with a width greater than the first slot, the first and second slots being oriented toward the pin support member. The temporary fixing assembly also includes a bar adapted to engage the first and second slots, the bar having a length greater than the width of the first slot and less than the width of the second slot.

[0030] - The internal and external components have generally rectangular cross sections, which advantageously include rounded corners;

[0031] - The base is mounted so that it is pivotable on the needle support about the pivot axis between the needle use position and the needle withdrawal position;

[0032] - The pivot axis is perpendicular to the longitudinal axis of the plunger, and in particular perpendicular to the sliding axis of the inner component relative to the outer component;

[0033] - The needle support or base includes a pin for guiding the base to pivot relative to the needle support, and another joint hole in the needle support and base defining a receiving pin;

[0034] - In the needle extraction position, the main section of the needle extends entirely within the internal receiving space defined by the plunger;

[0035] - The main section of the needle is located on one side of the free end of the needle;

[0036] - The main section defines the free end of the needle;

[0037] - A needle-forming elbow extends on one side of the free end by a main section extending along the lifting axis, and on the opposite side of the free end by a connecting section extending along the longitudinal axis of the plunger.

[0038] Another object of the present invention is a method for preparing to remove a needle previously introduced into a patient, the method being performed before the removal of the needle, the method comprising the following steps:

[0039] - Provide the apparatus as described above, wherein the extraction mechanism is in its inactive position and the plunger is in its retracted configuration;

[0040] - Move the internal member relative to the external member to move the plunger from its retracted configuration to its deployed configuration, thereby increasing the length of the plunger;

[0041] - Move the base from the inactive position of the extraction mechanism to the active position.

[0042] Another object of the present invention is to provide an injection method comprising the following steps:

[0043] - Provide the apparatus as described above;

[0044] - The needle is inserted into the patient's body, its tip piercing the cap of an implantable chamber; and

[0045] - The drug solution is injected into the implantable cavity via a needle;

[0046] -Prepare to remove the needle using the method described above;

[0047] - Remove the needle by moving the plunger from the needle use position to the needle removal position;

[0048] The method according to the invention includes, individually or in any technically feasible combination, one or more of the following features:

[0049] - The movement of internal components causes the temporary fixing mechanism at the base to fail, thus making the movement of the temporary fixing mechanism possible;

[0050] - After the needle is removed, the main section of the needle extends completely inside the plunger. Attached Figure Description

[0051] The invention will be better understood by reading the following description, which is given by way of example only and with reference to the accompanying drawings, in which:

[0052] - Figure 1This is a three-quarter perspective view of the injection device according to the present invention in a needle-use configuration;

[0053] - Figure 2 and Figure 3 They respectively showed from Figure 1 A longitudinal sectional view of the device viewed from the side and top;

[0054] - Figure 4 and Figure 5 They respectively showed from Figures 1 to 3 The device is viewed from the side and top in a longitudinal cross-sectional view, with the plunger in an unfolded configuration;

[0055] - Figure 6 and Figure 7 They were displayed respectively Figures 1 to 5 The rear three-quarters perspective view and vertical cross-sectional view of the device, with the extraction mechanism in an active configuration;

[0056] - Figure 8 yes Figures 1 to 7 A vertical side sectional view of the device in the needle extraction configuration. Detailed Implementation

[0057] Figures 1 to 8 An injection device 10 according to the invention is shown. Device 10 is intended to connect to an implantable chamber 11 ( Figure 1 (Illustrated schematically) for injecting a drug solution into an implantable chamber.

[0058] As is known per se, an implantable chamber 11 is placed under the patient's skin 12. The chamber 11 has a generally cylindrical reservoir 13, which is defined by a perforated membrane 14 on the surface of the reservoir that contacts the inner surface of the skin. The reservoir is connected to a tube (not shown) for delivering a drug solution to the organ to which the drug dose is to be delivered.

[0059] The injection device 10 includes a needle 22 integrated with a needle support 24, which extends from a tube connected to and secured (particularly glued to the needle support 24). According to the invention, the injection device includes a needle 22 extraction mechanism 50 carried by the needle support 24.

[0060] like Figure 2 As shown, needle 22 extends substantially along the lifting axis ZZ.

[0061] The needle 22 has a curved tip free end 28, so that the needle opens laterally relative to the lifting axis ZZ.

[0062] The support member 24 has a central core 30 that extends along a longitudinal axis YY perpendicular to the lifting axis ZZ. The central core 30 is substantially parallelepiped. A conduit 31 passes through the central core from one side to the other for conveying liquid to a needle 22, the conduit 31 extending along the longitudinal axis YY. The needle 22 is attached to one end of the central core 30 that forms the head 32.

[0063] Needle 22 forms a bend 34 (see) Figure 2 The elbow extends on one side of the free end 28 by a main section 35 extending along the lifting axis ZZ, and on the side opposite the free end 28 by a connecting section 36 extending along the longitudinal axis YY. The connecting section 36 engages in an axial conduit passing through the central core 30 from the head 32.

[0064] Support member 24 includes two hinge pins 38 (in) Figure 1 As can be seen in the image, the two hinge pins protrude laterally near the head 32, on either side of the central core 30. The hinge pin 38 extends along a transverse axis XX perpendicular to the lifting axis ZZ and the longitudinal axis YY.

[0065] Support member 24 also includes two lower retaining pins 39 (one of which is in Figure 6 (as can be seen in the middle) and two upper retaining pins 40 (one of which is in the middle) Figure 1 As can be seen in the image, these retaining pins protrude laterally from the central core 30, parallel to the transverse axis XX.

[0066] The lower retaining pin 39 extends further from the head 32 along the longitudinal axis YY from a portion of the central core 30 at the same height as the hinge pin 38 along the lifting axis ZZ.

[0067] The upper retaining pin 40 extends along the lifting axis ZZ below the hinge pin 38.

[0068] The lower retaining pin 39 and the upper retaining pin 40 have a smaller lateral range along the lateral axis XX than the hinge pin 38.

[0069] On the side of the support member 24 facing the needle 22, the support member 24 has a support plate 42 extending along the length of the support member 24. The head 32 protrudes from the support plate 42 along the longitudinal axis YY.

[0070] On the side of the support member 24 opposite to the needle 22, the support member 24 has a rod 44 for locking the extraction mechanism 50. The rod 44 extends along the longitudinal axis YY above the central core 30 on the side opposite to the head 32. The rod protrudes laterally from both sides of the central core 30 in a direction parallel to the transverse axis XX.

[0071] The injection device 10 according to the invention includes a needle 22 extraction mechanism 50, which is permanently connected to a needle support 24 and is operable relative to the needle support as follows: Figures 1 to 5 The location of the inactive extraction mechanism shown is similar to that of... Figures 6 to 8 The active extraction mechanism 50 moves between positions shown.

[0072] The extraction mechanism 50 includes a base 52 and a plunger 54, the plunger 54 being slidably mounted relative to the base 52. The base 52 is movable relative to the support 24, and is particularly hinged relative to the support about a hinge pin 38.

[0073] The base 52 includes a sleeve 56 that defines a circulation channel 58 for the plunger 54.

[0074] When the extraction mechanism 50 is in the inactive position, the sleeve 56 extends substantially in a direction parallel to the longitudinal axis YY.

[0075] When the extraction mechanism 50 is tilted to the active position, the sleeve 56 extends substantially in a direction parallel to the lifting axis ZZ.

[0076] The sleeve 56 is laterally open in a width corresponding to the width of the central core 30 of the support member. The sleeve 56 also defines a retaining cavity 59 on its upper surface, leading to the internal channel 58.

[0077] The base 52 also includes two flanks 60 that extend sleeves 56 on either side of the opening, adapted to engage around the central core 30. The flanks 60 have two hinge holes 62 into which hinge pins 38 are received for hinged engagement of the base 52 onto the central core 30.

[0078] The hinge axis is parallel to the transverse axis XX near the head 32, such that in the inclined position, the head 32 extends into the channel 58, as... Figure 7 As shown.

[0079] The side wing also has two lower retaining holes 63 (in Figure 7 (visible in the middle) and the upper retaining holes 64 on the inner surface of the two wing 60 (in the middle) Figure 1 (See in the middle).

[0080] The lower retaining hole 63 is adapted to receive the lower retaining pin 39 when the extraction mechanism 50 is in the inactive position, thereby allowing the extraction mechanism 50 to be temporarily retained in the inactive position.

[0081] Similarly, the upper retaining hole 64 is adapted to receive the upper retaining pin 40 when the extraction mechanism 50 is in the active position, thereby allowing the extraction mechanism 50 to be temporarily retained in the active position.

[0082] The base 52 also includes two lateral finger rests 65 that protrude from the sleeve 56 at the ends opposite the head 32.

[0083] The plunger 54 is received within the channel 58, and can be used as follows: Figures 1 to 7 The needle usage position shown is as follows: Figure 8 Slide between the needle extraction positions shown.

[0084] The plunger 54 includes an outer member 70 slidably mounted in a base 52; and an inner member 72 slidably mounted in the outer member 70 in a telescoping manner. The plunger 54 also includes a flexible interlocking mechanism.

[0085] The outer component 70 is a hollow sleeve with a cross-section complementary to that of the inner channel 58. This cross-section is essentially a rectangle with rounded corners.

[0086] The outer member 70 is open at the front end 74 near the head 32 and at the rear end 76 away from the head 32. The outer member 70 defines an internal passage 78 that is open at the front end 74 and the rear end 76.

[0087] The outer member 70 defines an outer shoulder 79 surrounding its front end 74 and a retaining pin 80 projecting from a top surface near the front end 74. The retaining pin 80 is adapted to be inserted into a cavity 59 in the needle 22 usage position. When the retaining pin 80 is received in the cavity 59, the outer shoulder 79 is adapted to abut against the front edge of the sleeve 56.

[0088] The outer member 70 defines an outer slot 90 oriented toward the needle support 24, opening from the front end 74 to the rear end 76 and leading into the inner channel 78. The outer slot 90 has a width greater than the length of the rod 44.

[0089] The internal component 72 is a hollow sleeve with a cross-section complementary to that of the internal channel 78. This cross-section is essentially a rectangle with rounded corners.

[0090] The internal member 72 has an open front end 92 and a rear end 94, the rear end being provided with a rear finger-like support 96. The internal member 72 defines an internal space 98 open at the front end 92.

[0091] The internal member 72 further defines an internal slot 100 oriented toward the needle support 24. The internal slot 100 is open from the front end 92 to the rear end 94 and leads into the internal space 98. The width of the internal slot 100 is less than the length of the rod.

[0092] The internal component 72 is slidably mounted in the internal channel 78 of the external component 70 along the longitudinal axis of the plunger 54. Therefore, the internal component 72 can be accessed from... Figures 1 to 3 The plunger 54 retraction configuration shown moves to, as Figures 4 to 8 The plunger 54 shown is in an extended configuration, and the length of the plunger 54 in the extended configuration is greater than the length in the retracted configuration.

[0093] When the plunger 54 is in the deployed configuration, the internal channel 78 of the outer member 70 and the internal space 98 of the outer member 72 form a continuous internal needle 22 receiving space defined by the plunger 54, such as Figure 8 As shown.

[0094] The rod 44, the outer slot 90, and the inner slot 100 form a temporary fixing assembly for the base 52 in the inactive position.

[0095] When plunger 54 is in the retracted configuration, the temporary fixing assembly is active, such as... Figure 3 As shown. Rod 44 extends into the internal space 98 and engages with the external slot 90 and the internal slot 100. Because the length of rod 44 is greater than the width of the internal slot 100, rod 44 prevents the plunger 54 from moving away from the support member 24. The base 52 is therefore fixed in the inactive position of the extraction mechanism 50.

[0096] When plunger 54 moves from the retracted configuration to the deployed configuration, the temporary fixing assembly fails, such as Figure 5 As shown. In this configuration, the internal member 72 has moved away from the rod 44 along the longitudinal axis YY. The rod 44 now engages only in the external slot 90, which is wider than the length of the rod 44. The base 52 can then be moved to the active position of the extraction mechanism 50.

[0097] When the plunger 54 is in the deployed configuration, the interlocking mechanism is adapted to lock the movement of the inner member 72 relative to the outer member 70.

[0098] The flexible interlocking mechanism includes an upper snap-fit ​​tab 82 supported by an external member 70 on the upper surface at the rear end 76. The upper snap-fit ​​tab 82 is supported by teeth at its free end facing the internal channel 78.

[0099] The flexible interlocking mechanism also includes two lateral snap-fit ​​tabs 102 carried by the internal member 72 along two sides, each lateral snap-fit ​​tab 102 carrying a tooth at its free end, facing outwards. The flexible interlocking mechanism includes a front housing 84 and a rear housing 86 defined in the sides of the external member 70, such as... Figure 3 and Figure 5 As shown.

[0100] The teeth of the lateral snap-fit ​​tab 102 are asymmetrical, meaning they have a blocking side and a passing side. For example, the normal on the blocking side forms a substantially zero angle with the lateral snap-fit ​​tab 102, while the normal on the passing side forms an angle between 30° and 60° with the snap-fit ​​tab 102.

[0101] The flexible interlocking mechanism also includes a ramp 106 and an upper housing 108, the ramp extending through the top of the inner member 72, the ramp 106 defining the upper housing 108 at its upper end.

[0102] In the unfolded configuration, each tooth carried by the lateral snap-fit ​​tab 102 is received by one of the rear housings 86, such as Figure 5 As shown, the teeth supported by the upper snap-fit ​​tab 82 are received by the upper housing 108, as... Figure 4 As shown.

[0103] Advantageously, the flexible interlocking mechanism is suitable for temporarily holding the internal member 72 with respect to the external member 70 when the plunger 54 is in the retracted configuration.

[0104] Temporary holding means that the force required for plunger 54 to leave the retracted configuration is high enough so that plunger 54 will not leave the deployed configuration without user intervention, but low enough for such user intervention so as not to cause shaking in the injection device 10 when the plunger leaves the retracted configuration. This force is advantageously between 6 N and 10 N.

[0105] In the retracted configuration, each tooth, carried by the lateral snap-fit ​​tab 102, is received by one of the front housings 84 defined by the outer member 72. As the plunger 54 moves from the retracted configuration to the unfolded configuration, the through side of each tooth rests on the edge of the front housing 84, thereby allowing the tooth to move out of the front housing 84 when the user pulls the inner member 72, with reduced force.

[0106] Conversely, when the plunger 84 is in the deployed configuration, each tooth carried by the lateral snap-fit ​​tab 102 is received by one of the rear housings 86. The locking side of each tooth rests on the edge of the rear housing 86, thereby preventing the tooth from moving out of the rear housing 86. The flexible interlocking mechanism thus prevents the internal member 72 from moving away from the deployed configuration.

[0107] The method for operating the injection device 10 and, more specifically, the method for removing the needle 22 will now be described.

[0108] The injection device 10 was initially in Figures 1 to 3 The configuration shown has the needle 22 passing through the patient's skin 12 to reach the implantable chamber 11 below. A support plate 42 rests on the patient's skin.

[0109] The plunger 54 is in its retracted configuration and the extraction mechanism is in the inactive position. The plunger 54 extends substantially parallel to the longitudinal axis YY.

[0110] The plunger 54 is in the needle 22 use position, and the shoulder of the front end 74 of the outer member 70 abuts against the front of the sleeve 56, near the head 32. The retaining tab 80 engages in the retaining cavity 59 to hold the plunger 54 in the needle 22 use position.

[0111] The teeth of the side-clamping tab 102 engage in the front housing 84, thereby holding the plunger 54 in the retracted configuration.

[0112] The rod 44 is located in the internal space 98 of the internal member 72, engaging in both the overlapping internal slot 100 and the external slot 90. Because the length of the rod 44 is greater than the width of the internal slot 100, the rod 44 completely locks the plunger 54 against the central core 30 and prevents the base 52 from tilting to the active position.

[0113] In the retracted configuration, the length of the plunger 54 is minimized, thereby reducing obstruction of the device 10 to the patient.

[0114] In the first step, the user pulls the internal component 72 via the rear finger support 96 to move the plunger 54 from its retracted configuration to its deployed configuration, as... Figures 4 to 8 As shown.

[0115] The inner member 72 slides into the outer member 70 along the YY axis. The length of the plunger 54 is increased such that the plunger length in the deployed configuration exceeds 120% of the length in the retracted configuration, preferably more than 125% of the length in the retracted configuration.

[0116] The teeth of the lateral snap-fit ​​tab 102 extend from the front housing 84 and then engage the rear housing 86 in the unfolded configuration. A latch tooth travels along the ramp 106 and engages the upper housing 108 in the unfolded configuration. An interlocking mechanism then locks the plunger 54 in the unfolded configuration.

[0117] The lever 44 is released from the inner slot 100 and engages only in the outer slot 90. The lever no longer locks the plunger 54 against the central core 30. The bottom retaining pin 39 engages in the bottom retaining hole 63 and holds the base 52 in the inactive position.

[0118] In the second step, the user tilts the base 52 around the retaining pin from the inactive position to the active position. In the active position, as... Figures 6 to 8 As shown, plunger 54 extends substantially parallel to the lifting line ZZ.

[0119] The head 32 is then received in the internal channel 78. The top retaining pin 40 engages in the top retaining hole 64 to secure the base 52 in the active position.

[0120] In the third step, while holding the lateral finger support 65 with two other fingers, the user pushes the rear finger support 96 with their thumb to allow the plunger 54 to slide within the channel 58. The plunger 54 then... Figure 6 and Figure 7 The needle 22 shown is moved to the position indicated. Figure 8 The extraction location of needle 22 is shown.

[0121] When the needle 22 is moved from the use position to the extraction position, the retaining pin 80 is pushed out of the retaining cavity 59 by the user.

[0122] Then, the shoulder of the front end 74 of the outer member 70 rests against the patient's skin, providing sufficient bearing surface, and the user pushes the plunger 54 to move the base 52 upward, thus removing the needle 22 from the patient's body. The plunger 54 gradually swallows the needle 22.

[0123] At the needle 22 extraction position, the main segment 35 of the needle 22 extends entirely within the receiving space of the plunger 54, with the tip 74 extending beyond the free end 28. This protects the user by preventing any risk of accidental puncture.

[0124] It is conceivable that the extraction mechanism 50 occupies less space in this injection device 10, especially when the plunger 54 is in the retracted position and has a reduced length. This reduces the space occupied by the injection device on the patient's skin, thereby reducing the risk of manipulation errors during injection of the drug solution, as well as the risk of tipping due to the pendulum effect of the plunger 54. The reduced size of the injection device 10 also improves patient comfort.

[0125] In addition, the device 10 includes a flexible interlocking mechanism consisting of multiple snap-fit ​​tabs and associated housings, which ensures that the plunger is securely locked in the unfolded configuration to ensure effective extraction.

[0126] Finally, the temporary fixation of the base 52 in the inactive position, combined with the temporary positioning of the plunger in the retracted configuration via a flexible interlocking mechanism, ensures that the base 52 and plunger 54 remain inactive without external manipulation by the operator. This further reduces the risk of operator error.

Claims

1. An injection device (10), the injection device comprising: - Needle support (24); - An injection needle (22), which is integrated with the needle support (24) and has a free end (28) disposed away from the needle support (24); and - An extraction mechanism (50) for extracting the injection needle (22), the extraction mechanism including a base (52) connected to the needle support (24) and a plunger (54), the plunger being movable relative to the base (52) between a use position of the injection needle (22) and an extraction position of the injection needle (22), the base (52) being movable relative to the needle support (24) between an inactive position and an active position of the extraction mechanism (50), wherein the injection needle is configured to be removed by moving the plunger from the use position of the injection needle to the removal position of the injection needle. The plunger (54) is characterized in that it includes an outer member (70) and an inner member (72), the inner member (72) being movable relative to the outer member (70) from a retracted configuration to an extended configuration of the plunger (54) in a non-active position of the extraction mechanism (50), the plunger (54) having a longer length in the extended configuration than in the retracted configuration, wherein the plunger defines an internal space for receiving the injection needle in the extended configuration.

2. The apparatus (10) according to claim 1, wherein, The internal component (72) is slidably mounted in the internal channel (78) of the external component (70).

3. The apparatus (10) according to any one of claims 1 or 2, wherein, The plunger (54) includes a flexible interlocking mechanism adapted to lock the internal member (72) relative to the external member (70) when the plunger (54) is in the deployed configuration.

4. The apparatus (10) according to claim 3, wherein, The flexible interlocking mechanism includes: at least one snap-fit ​​tab (82, 102) held by the inner member (72) or the outer member (70); and at least one housing (86, 108) defined by another of the inner member (72) and the outer member (70); wherein the snap-fit ​​tab (82, 102) has teeth receiving in the housing (86, 108) when the plunger (54) is in its deployed configuration.

5. The apparatus (10) according to claim 4, wherein, The housing (86, 108) or each of the housings (86, 108) is located near the first end (76) of another of the inner member (72) or the outer member (70) so as to receive one of the teeth when the plunger (54) is in its deployed configuration. The flexible interlocking mechanism also includes at least one second housing (84) located near the second end (74) of another of the inner member (72) or the outer member (70) so as to receive the teeth when the plunger (54) is in its retracted configuration.

6. The apparatus (10) according to claim 4, wherein, The flexible interlocking mechanism includes at least one ramp (106) extending above the other of the inner member (72) and the outer member (70), the ramp (106) defining one of the housings (108) at its top end, and the snap-fit ​​tab (82) being carried on the ramp (106) when the plunger (54) moves from the retracted configuration to the unfolded configuration.

7. The apparatus (10) according to claim 3, wherein, The flexible interlocking mechanism is adapted to temporarily hold the internal member (72) relative to the external member (70) when the plunger (54) is in the retracted configuration.

8. The apparatus (10) according to any one of claims 1 or 2, wherein, The device (10) includes an assembly for temporarily fixing the base (52) in the inactive position, the assembly being active when the plunger (54) is in the retracted configuration and disabling when the plunger (54) moves from the retracted configuration to the deployed configuration.

9. The apparatus (10) according to claim 8, wherein, The assembly includes a first slot (100) extending on the inner member (72) and a second slot (90) extending on the outer member (70), the width of the second slot being greater than the width of the first slot (100), the first slot (100) and the second slot (90) being oriented toward the needle support member, the assembly also including a rod (44) adapted to engage the first slot (100) and the second slot (90), the length of the rod (44) being greater than the width of the first slot (100) and less than the width of the second slot (90).

10. The apparatus (10) according to any one of claims 1 or 2, wherein, The inner component (72) and the outer component (70) have generally rectangular cross sections with rounded corners.

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