Drug delivery device The present application relates to a drug delivery

Abstract

The invention relates to a drug delivery device comprising a main body (12), a drug container (24) provided with a drug delivery member (26) arranged in the main body (12), a drive unit comprising a plunger rod (90) and a drive spring (96), the drive unit being operatively connected to the drug container (24), an activator (36, 72, 104) operatively connected to the drive unit, a safety mechanism (88) operatively connected to the plunger rod (90), wherein in an initial state of the device the plunger rod (90) is held with the drive spring (96) in a tensioned state and wherein the safety mechanism (88) is in contact with the plunger rod (90) and prevents release of the plunger rod, wherein when the device is pressed against an injection site the activator (36, 72, 104) acts on the safety mechanism (88) to move the safety mechanism (88) out of contact with the plunger rod (90) and wherein the activator (88) acts on the plunger rod (90) to release the plunger rod (90) such that the plunger rod (90) acts on the drug delivery container (24) to deliver a drug at the injection site.

Description

Technical Field

[0001] This invention relates to a drug delivery device, and more particularly to an auto-injector. Background Technology

[0002] For many years, self-administering drug delivery devices have been available on the market. Many of these devices are designed as autoinjectors, with the aim of requiring end-users to perform as few steps as possible to initiate the injection.

[0003] US 3,797,489 discloses an autoinjector with a pre-tensioned drive spring operably connected to a plunger rod. To activate the device, a safety cap with a safety pin is removed, and the device is pressed against the injection site. The user then presses a button on the rear end of the device, causing the syringe with the needle to move forward and perform a puncture. The release of the plunger rod then induces injection. The retraction spring is then tensioned so that when the device is removed after injection, the syringe and needle are returned to the syringe.

[0004] US 5,681,291 discloses an autoinjector having a needle cap movable within the housing of the device. When the injector is pressed against the injection site, the needle cap moves rearward, resulting in manual puncture. The movement of the needle cap also activates a drive spring that acts on a plunger rod to perform injection. When the device is removed from the injection site, the spring pushes the needle cap to a position covering the needle, where the needle cap is locked.

[0005] Even though many of these devices on the market are sufficiently functional and robust, there is always room for improvement. Summary of the Invention

[0006] The purpose of this invention is to provide a drug delivery device with highly robust, reliable functionality and safety features.

[0007] This objective is achieved by the drug delivery device according to the independent claim. Preferred embodiments of the invention form the subject matter of the dependent claims.

[0008] According to a key aspect, a drug delivery device is provided, comprising a housing, a drug container having a drug delivery member disposed within the housing, and a drive unit including a plunger rod and a drive spring.

[0009] The drive unit can be operatively connected to the drug container, the activator can be operatively connected to the drive unit, and the safety mechanism can be operatively connected to the plunger rod.

[0010] In the initial state of the device, the plunger rod is held in place by a tensioned drive spring, and a safety mechanism is in contact with the plunger rod and prevents its release, ensuring that the device cannot be accidentally activated.

[0011] When the device is pressed against the injection site, the activator acts on the safety mechanism, causing the safety mechanism to move out of contact with the plunger rod, thus activating the device.

[0012] Furthermore, the activator acts on the plunger rod to release it, thereby allowing the plunger rod to act on the drug container to deliver the drug at the injection site. Because the activator (directly or via an intermediate element) actively acts on the plunger rod to release it, precise activation is ensured. Since activation does not depend on a component sliding on a surface providing frictional resistance under the force of a drive spring, the reliability of the release system is improved.

[0013] Therefore, when the device is used for injection, the activator works to remove the safety mechanism and begin the injection.

[0014] According to another aspect, the activator may include a release sleeve provided with a release member that is movable to contact the plunger rod to release the plunger rod. When using a release element, the release sleeve is a robust and functional design.

[0015] The drug delivery device may also include a needle cap designed to move into the body and move a release sleeve. Thus, the needle cap and release sleeve cooperate for device activation.

[0016] Furthermore, the plunger rod may include a plurality of flexible arms, wherein the plurality of flexible arms may include protrusions that engage with flanges fixed in the device, and wherein a release member actuates the protrusions to bend the plurality of arms to release the plunger rod. In this regard, a safety mechanism may include a safety pin that contacts the plurality of flexible arms to prevent release of the plunger rod. The safety pin ensures that the device is not accidentally activated, for example, during transport or when a user drops the device.

[0017] According to another option, a safety pin may be included in the release sleeve, the safety pin being designed to disengage from the plurality of arms of the plunger rod when the release member moves to contact the protrusions of the plunger rod and pushes the protrusions of the plunger rod. With this design, the release sleeve includes several functions.

[0018] Furthermore, the drug delivery device may include an intermediate release member that contacts a protrusion of the plunger rod, wherein a release member of the release sleeve pushes the intermediate release member to release the plunger rod. The intermediate release member facilitates the design and function of the release mechanism.

[0019] According to another aspect, the device may include a needle cap spring acting on a release sleeve, whereby, after the device is removed from the injection site, the release sleeve and needle cap move to a forward position, wherein the needle cap covers the drug delivery member. Again, the release sleeve and needle cap act together to cover the needle after injection.

[0020] To ensure safety against accidental needle pricks, the release sleeve may also include a locking member designed to lock the release sleeve and needle cap in a forward position. Similarly, the release sleeve is designed to have multiple functions. In this regard, the locking member may include an opening and a spring housing attached to the body, the spring housing including a flexible locking member arranged to bend into the opening.

[0021] According to another approach, the spring housing may be designed to be generally tubular and elongated, surrounding the drive spring to control the buckling of the drive spring during injection, thereby ensuring reliable function of the device. The spring housing may include a central channel, with a flange positioned adjacent to the central channel. The spring housing may also include a support member designed to contact and support the rear surface of the syringe. The spring housing may further include an auditory / tactile member designed to contact and slide along the drive spring during injection, thereby providing auditory / tactile information to the user. The spring housing is also designed to have multiple functions.

[0022] According to another aspect, the device may include a syringe retainer, which may include an opening surrounded by a support surface. The body may be provided with an opening, wherein the support surface is designed to snap into the opening of the body, thereby attaching the syringe retainer to the body. The syringe retainer may also include a seat designed to support a flange at the rear end of the syringe.

[0023] The drug delivery device may also include a cap attachable to the front end of the device, the cap including flexible hooks that engage a needle cover covering the drug delivery component, wherein removal of the cap removes the needle cover. In this respect, the cap may also include flexible hooks in the front region of the cap for retaining the needle cover after removal.

[0024] These and other aspects and advantages of the invention will become apparent from the following detailed description and accompanying drawings. Attached Figure Description

[0025] In the following detailed description of the invention, reference will be made to the accompanying drawings, wherein... Figure 1-2 A cross-sectional view of a first embodiment of the drug delivery device according to the present invention is shown. Figure 3-21 It shows that it includes Figure 1 and2 Different parts and components in the device, Figure 22-30 Show Figure 1 and 2 The different functional states of the device, Figures 31-32 A cross-sectional view of a second embodiment of the drug delivery device according to the present invention is shown, and Figure 33-39 It shows that it includes Figure 31 and 32 Different parts and components in the device. Detailed Implementation definition

[0026] The “front” side of the device refers to the needle side of the device, where the needle extends during injection.

[0027] "Back" side - opposite to the side where the needle protrudes during injection.

[0028] Figures 1 to 30 A first embodiment of the drug delivery device 10 is shown. This first embodiment is designed for subcutaneous injection of small volumes of drug within 1 ml. Figure 3 and 4 As shown, it includes an elongated, typically tubular, body 12. Wings 14 are provided on the outer surface of the body 12. The outer surface of the body 12 is also designed with labels containing relevant information. The wings 14 on the outer side of the body 12 serve both as rolling stops and as a gripping feature for the user. A recess 15 is provided in front of the wings. An opening 16 is also provided on the body 12. A longitudinally extending guide flange 17 is provided on the inner surface of the body 12. A longitudinally extending guide groove 19 is also provided on the inner surface of the body 12, and the guide groove has a rearward-facing stop flange 21.

[0029] like Figure 5 and 6 As shown, a syringe holder 18 is attached within the body 12. The syringe holder 18 has an outwardly extending wall 20 that forms an opening into the interior of the syringe holder 18, which, together with the opening 16 of the body 12, forms an observation window 22. The wall 20 is designed to fit into the opening 16, wherein the syringe holder 18 is designed with flexible sections that allow the wall to compress inward during assembly and then snap into the opening 16, thereby locking the two components together. Figure 6 As shown.

[0030] Within the syringe holder 18, a syringe 24, preferably made of glass, can be placed, comprising an injection needle 26 and a movable plunger 28. Before use, the needle is preferably protected and kept sterile by a rigid needle cap RNS 29. The syringe and its contents are visible through the observation window opening 22. The syringe holder 18 is designed with a guide 30 that radially supports the syringe 24. The flange 32 of the syringe 24 is supported by a seat 34 of the syringe holder 18 to prevent forward movement. The syringe holder 18 controls the position of the tip of the needle 26 by supporting the glass flange 32. This provides a defined length dimension with tolerances to be considered. The surface of the seat 34 of the syringe holder 18 is designed to minimize glass breakage by being smooth and without a single point of contact. The seat 34 can be fitted with rubber sections, such as 2K moldings or O-ring assemblies, to further smooth the contact surface and thus prevent glass flange breakage. The seat 34 of the syringe holder 18 is also designed for a syringe "cutting flange" that maintains the rotational orientation of the flange. However, syringes with a "small rounded flange" can also be fitted into the syringe holder. The small rounded flange has the advantage of being more robust and reducing the risk of glass breakage. Furthermore, the outer surface of the seat 34 is provided with a flat surface, and protrusions 35 (described below) for guiding support are provided on each side.

[0031] like Figure 7 As shown, the device also includes a needle cap 36, which is part of the device's activator. The needle cap 36 is generally tubular and arranged to extend a distance from the front end of the body 12. The rear end of the needle cap 36 has two legs 38 extending in a rearward direction. An opening 40 in the front end of the needle cap 36 is small enough to prevent the passage of a ball with a diameter of 12 mm. This is a standard requirement to prevent accidental needle pricks in the fingers. The legs of the needle cap 36 are designed to fit into guide recesses 19 in the body 12, where a stop flange 21 interacts with the forward-facing surface 42 of the legs 38, which restricts the forward movement of the needle cap 36 and prevents it from falling off. An opening 46 is arranged in the side of the needle cap 36, allowing movement of the needle cap around the observation window wall 20 formed in the syringe holder 18. The inner surfaces of the legs 38 of the needle cap are planar, and the width of the legs 38 allows them to be guided by protrusions 35 in the syringe holder 18. This also allows the leg 38 to be manufactured with a greater thickness, while the syringe holder 18 still has an edge that guides the rotation of the syringe flange, which is active from a manufacturing point of view.

[0032] like Figure 8 and 9As shown, a generally tubular spring housing 48 is also disposed within the main body. A guide plate 50 is disposed at the front end, which has outwardly extending protrusions 52 that fit between guide flanges 17 on the inner surface of the main body 12, allowing axial movement of the spring housing 48 but guiding rotation about the main body 12. The outer surface of the guide plate 50 is also designed with a planar cutout 53, which is designed to guide the legs 38 of the needle cap 36. The guide plate 50 has a forward-extending feature 54 that contacts the rear surface of the flange of the syringe 24 and holds it in its axial position, preventing it from moving backward beyond a certain point. Figure 8 As shown, feature 54 can be a tubular body with a notch 55. Alternatively, a protruding rib can be provided that extends forward and terminates a short distance before the flange of the syringe 24. The purpose of feature 54 is to hold the syringe in its position if it has slid a distance backward from the syringe holding surface 34, so that it will not be subjected to high impacts depending on syringe acceleration in the flange region and will stop upon activation.

[0033] The front region of the spring housing 48 is further provided with a flexible arm 56 extending in the forward direction, wherein the free end of the flexible arm 56 is provided with an outwardly extending locking hook 58, the function of which will be described below. The outer surface of the spring housing has a longitudinally extending planar surface 60. The rear region of the spring housing is designed with two longitudinal slits 62, thereby forming two flexible arms 64. At the rear end of the arm 64, an outwardly extending wedge 66 is arranged. In front of the wedge 66, an elongated slit 68 is arranged. A transverse wall 70 is arranged inside the spring housing at the region where the slit 68 terminates in the forward direction. Figure 9 As shown, the transverse wall 70 is provided with a central channel 71, and a flange 73 is formed on the transverse wall 70 between the channel 71 and the slit 68.

[0034] like Figure 10-12 As shown, the device also includes a release sleeve 72, which is part of the device's activator and safety mechanism. The front portion of the release sleeve 72 is generally tubular and has a front plate 74 that interacts with the end face of the leg 38 of the needle cap 36, so that the release sleeve 72 also moves in a rearward direction as the needle cap 36 moves. Figure 1 As shown, the release sleeve 72 has a spring seat 76 for the needle cap spring 78. The needle cap spring 78 should be stiff enough to function as a transport safety mechanism, keeping the device safe along with the design of the device's components and not being activated by vibrations and shocks that may occur during transport. The seat 76 is deep enough to prevent the coil wire end from being pushed outside the spring diameter and getting stuck or interfering with the body 12 during movement. The spring seat 76 has the maximum diameter of the release sleeve component, but is still small enough to avoid contact with the interior of the body 12.

[0035] If / when the needle cap spring 78 buckles away from the ideal axial position, the inner surface of the body 12 is a portion that guides the needle cap spring 78 radially. The outer diameter of the front section of the release sleeve 72 serves as an inner guide for the needle cap spring 78 to prevent buckling. The front section also has an opening 80 at the rear of the front plate 74. A cutout 81 is formed in the outer surface of the front plate, and the guide flange 17 of the body 12 engages in the cutout 81, thereby providing rotational locking between the components but allowing axial movement of the release sleeve 72 about the body 12. The inner surface of the release sleeve 72 is also provided with a generally planar flange 82 designed to slide against the planar surface 60 of the spring housing 48. The rear end of the flange 82 is provided with a wedge-shaped surface 83. The rear end of the release sleeve 72 is designed to have two elongated arms 84. A laterally extending beam 86 or bridge is provided between the arms 84. An elongated safety pin 88 extending in the forward direction is provided on the forward-facing surface of the beam 86.

[0036] The device is also equipped with a plunger rod 90, such as Figure 13 As shown, the plunger rod has a slender cylindrical body, which can be solid or hollow, and has an enlarged section 92 at its front end. Figure 1 As shown, the rear surface of the enlarged section has a groove formed as a seat 94 for the drive spring 96. This prevents the wire end of the drive spring from sliding radially out and contacting the inner wall of the glass syringe 24. The rear section of the plunger rod 90 is provided with an elongated slit 98, thereby forming two flexible arms 100. The width of the slit 98 corresponds approximately to the thickness of the safety pin 88. The free ends of the arms 100 are provided with outwardly extending protrusions or hooks 102. The front surface of the hook 102 is formed as a flange that mates with the flange 73 of the spring housing, as will be explained. The plunger rod 90 is surrounded by the drive spring 96, which is located between the seat 94 of the plunger rod and the forward-pointing surface of the transverse wall 70 of the spring housing 48.

[0037] like Figure 14 As shown, the device also includes a trigger 104, which is part of the device's activator. The trigger 104 includes a cylindrical body 106 with a forward-pointing leg 108, wherein the free end of the leg is provided with an outward-pointing flange 110. The trigger is positioned such that the flange 110 in the initial position contacts the outer surface of the plunger hook portion 102.

[0038] like Figure 15As shown, the device also includes an end cap 112, which has a generally tubular body 114 and a rear end plate 116, to which the end cap is attached and covers the rear end of the body 12. This attachment is provided by a protrusion 118 on the outer surface of the body 114 engaging with a cutout 120 at the rear end of the body. When using the device, the user can use the end cap 112 as a good gripping part, depending on their gripping preference. The end cap 112 has a rear outer surface that, when compared to the needle cap side of the device, clearly shows that it is blocked and is not the needle side of the device. The outer surface of the body 114 of the end cap 112 is provided with an axially outwardly pointing protrusion 122, which fits between the guide flanges 17 of the body 12. If the user attempts to twist the rear end cap 112 on the device, the protrusion 122 will prevent the end cap 112 from rotating. The end cap 112 has a forward-pointing spring seat 124 for the needle cap spring 78. The seat 124 is deep enough to prevent the end of the coil wire from being pushed into the spring diameter and jamming or interfering with the release sleeve 72 during the injection stroke. Furthermore, the inner surface of the end cap 112 serves as a rear stop for the trigger 104. The end cap 112 also has a rearward-facing flange 125 on which the flange 66 of the spring housing 48 rests, in which the rear end surface of the spring housing 48 rests against the inner surface of the end cap 112, thereby locking the spring housing 48 to prevent movement.

[0039] Figure 16-18 The roughly tubular cap 126 is designed to be attached to Figure 1 The front end of the device shown. The cap may have an opening 128 on its side surface, which provides access to an observation window within the body if the medication is not photosensitive and the user examines the medication before removing the cap 126. Alternatively, the cap 126 may be designed to extend over the observation window 22 to block UV light capable of degrading the medication in the syringe 24. The cap 126 has an end surface 130 with a small central channel 132. The cap 126 has a protrusion 134 on its inner surface, see [reference needed]. Figure 1 The cap 126 interacts with a recess 15 on the outer surface of the body 12. In this respect, the cap is designed so that the cap and protrusion can bend radially into and out of the recess 15. The cap 126 also has wings 136 on its outer side, which serve as rolling stops and gripping features. The cap 126 has a slot opening 138 at the rear of the protrusion 134 that interacts with the wings 14 on the body 12. This prevents the cap 126 from rotating during the first segment of withdrawal, which carries the risk of a rubber core appearing in the needle 26 of the syringe 24 if the rubber of the RNS 29 rotates on the needle 26. The cap 126 has an inner semi-circular leg 140 with an inwardly pointing hook 142 that will... Figure 1The hook 142 is positioned around the rear edge of the RNS 29 to grip and pull the RNS 29 from the needle 26 during cap removal. The hook 142 also prevents the RNS 29 from falling out of the cap 126 in a rearward direction. A flexible arm 144 in the front region of the cap 126 adjacent to channel 132 prevents the RNS 29 from falling out of the cap 126 in a forward direction. An internal rib 146 of the cap 126 prevents the cap 126 from being pushed too far against the front surface of the body 12.

[0040] The device may also be equipped with a signal component 150, which can notify the user when the device is activated during injection. It includes... Figure 19 The annular body 152 shown is configured to be press-fitted to... Figure 20 Feature 54 is located at the front end of the spring housing 48. The main body 152 may have a cutout 154 on its inner surface to form a locking washer function. The main body is provided with a tongue 156, which is formed such that the center of the main body 152 is inclined inwards. (As shown...) Figure 20 As shown, the end of the tongue 156 is configured to contact the coil of the drive spring 96. The signal component 150 may be made of metal or a relatively rigid plastic material.

[0041] Figure 21 An indicating member in the form of a sheath or sleeve diaphragm 158 is shown, which may be a thin plastic tube, somewhat similar to a drinking straw, attached to the front end of the plunger rod 90 and the drive spring 96. The sleeve diaphragm 158 is preferably attached only to the front end of the plunger rod 90, for example, by snap-fit, press-fit, or adhesive. A signal sleeve may also be positioned between the signal member 150 and the drive spring, such that the rear portion of the coil is covered while the front portion is uncovered, thereby ensuring that the signal member only contacts the coil at the end of the injection stroke, generating a signal only at the end of the injection, allowing the indicating device to be removed from the user.

[0042] like Figure 22-30 As shown, the complete device functions as follows. The device is shown without the cap and body, and sometimes in sectional view to enhance the visibility of the mechanism.

[0043] When the device is assembled, the drive spring 96 is tensioned around the plunger rod 90. The plunger rod 90 remains in the inactive position because its hook 102 engages the flange 73 of the spring housing 48. Figure 22 As shown, the two flexible arms 100 of the plunger rod 90 are prevented from moving radially toward each other by a safety pin 88 disposed in the slit 98. The safety pin 88 ensures that the device cannot be accidentally triggered during storage, transportation, or handling before use. Furthermore, as... Figure 23As shown, the beam 86 of the release sleeve 72 is positioned to rest against the rear end of the plunger rod 90. This ensures that the release sleeve 72 cannot travel further forward than it is currently in. The needle cap 36 is in its extended position under the force of the needle cap spring 78, thereby covering the needle 26.

[0044] In use, the cap 126 is removed as described above, thereby removing the RNS 29 from the needle 26. When the cap 126 has been removed, the needle cap 36 moves freely forward a short distance. The needle cap 36 is capable of producing a clicking sound between the release sleeve 72, which blocks the needle cap in the rearward direction, and the body 12 feature 21, which blocks the needle cap in the forward direction. An intentional feature is that the brief, free "clicking movement" of the needle cap 36 before injection when the cap 126 has been removed is a signal that the device is active and ready for use. When the device is in use, the aforementioned gap is reduced.

[0045] The device is placed on and pressed against the injection site, thereby causing puncture of the needle 26. Figure 24 As shown, this movement causes the needle cap 36 to overcome the force of the needle cap spring 78 and be pressed into the housing, thereby pushing the release sleeve 72 in a rearward direction due to the action of the leg 38 of the needle cap 36 on the front plate 74. Figure 25 As shown, the movement of the release sleeve 72 first removes the safety pin 88 from its initial position in the slot 98 between the plunger rod hooks 102. The safety pin 88 is designed to disengage from the plunger rod 90 before the device is activated. It should be noted that the plunger rod hooks 102 can still be hooked onto the flange 73, where they are mounted according to the design of the contact surfaces of the hooks 102 and the flange 73. Figure 26 As shown, the flange 82 of the release sleeve 72 will contact the trigger flange 110, and, as Figure 27 As shown, during further movement of the release sleeve, the flange 82 of the release sleeve 72 will push the leg 108 of the trigger 104 radially toward the center.

[0046] As described above, flange 82 may be provided with a wedge-shaped surface 83 to achieve a smooth user feel when reaching the final segment of the activation stroke. However, this depends on the angle in the geometry to give the "activation point". Flange 82 guides release sleeve 72 radially, thereby minimizing tolerances and misalignments of the activation mechanism.

[0047] like Figure 28 As shown, the radial movement of the trigger leg 108 will push the hook 102 of the plunger rod 90 away from the edge where they are mounted. This will activate the injection as the drive spring 96 will move the plunger rod 90.

[0048] The contact surfaces of the plunger hook 102 and the flange 73 of the spring housing 48 are preferably designed with a chamfer so that the hook 102 can remain suspended on the flange 73 by itself even when the safety pin 88 has been removed. This creates an active activation point when the plunger hook 102 is mechanically pushed away from the flange 73 by the trigger 104 and the release sleeve 72, thus successful activation does not depend on a component sliding on a surface providing frictional resistance under the force of the drive spring. However, if it is desired to minimize the force at the end of the needle cap 36's stroke, the contact surfaces of the plunger hook 102 and the flange 73 of the spring housing 48 can be designed with bevels in opposite directions, which would allow the hook 102 to slide off the flange 73 once the safety pin 88 has been removed. On the other hand, this arrangement increases the force required earlier in activation, as the plunger hook 102 compresses the safety pin 88 and provides frictional resistance to its withdrawal. If the hook 102 cannot slide completely by itself, the release sleeve 72 and the trigger 104 will still push them together to achieve a foolproof activation system.

[0049] Once the device is activated and the drive spring 96 extends, the spring housing 48 guides the outer diameter of the drive spring 96. The rear end of the drive spring 96 is no longer radially supported by the plunger rod 90. This support from the spring housing 48 prevents the long drive spring 96 from buckling. The movement of the plunger rod 90, in turn, causes the plunger 28 within the syringe 24 to move, and a dose of medication is expelled through the needle 26. During injection, if the signal member 150 is used, its tongue 156 will interact with the spring coil of the drive spring 96 to produce a distinct clicking sound as it passes the spring wire. The frequency of the continuous clicking sound will change during the injection stroke depending on two things: the speed of movement of the plunger rod 90 will decrease as the force from the drive spring 96 decreases, the more it extends, and the further the plunger rod 90 moves, the wider the spring coil pitch will expand.

[0050] During and after injection, the plunger rod 90 is visible through the observation window opening 22. The plunger rod 90 is partially covered by the coil of the drive spring 96. However, the color of the plunger rod 90, along with the visible drive spring 96, can be used as a signal to the user to indicate that the injection is complete. If a diaphragm sleeve is used, the color is visible in the observation window after use, partially or completely covering the window. After use of the device, the signal diaphragm sleeve 170 will partially or completely conceal the coil of the drive spring 96 so that it is not visible in the observation window. The signal diaphragm sleeve 170 has an optional function to prevent the drive spring 96 from contacting the inner glass wall of the syringe 24.

[0051] As the device is removed from the injection site, the needle cap spring 78 pushes the release sleeve 72 forward, which in turn pushes the needle cap 36 forward. Since the plunger rod 90 has moved from the inner wall 70, the release sleeve 72 is now able to travel further forward and reach the locked position. The needle cap spring 78 pushes the release sleeve 72 forward, where the arm 56 bends inward, and the tip of the release sleeve 72 moves past the locking hook 58 on the spring housing 48, where the outwardly projecting locking hook 58 enters the opening 80 of the release sleeve. Figure 29 and 30 As shown, the needle cap 36 is thus locked in the extended position by releasing the sleeve 72 via the leg 38 of the needle cap 36.

[0052] Figures 31 to 39 A second embodiment of the drug delivery device is shown. Many components are identical, and the function of the second embodiment is the same as that of the first embodiment, and will not be described in detail again. However, differences will be highlighted. The second embodiment is designed for intramuscular injection of larger doses than that of the first embodiment. The body 12 of this embodiment is substantially the same. However, at the front end of the body, a flange 160 is disposed on the inner surface to provide a stop flange for the needle cap 36, as shown. Figure 33 As shown. Additionally, the syringe holder 18 has a guide 162 at its rear end for guiding the syringe flange, which may be a flange with a cut-off portion, such as... Figure 34 As shown.

[0053] The spring housing 48 of the second embodiment has a slightly different design. For example, as Figure 35 As shown, a longitudinal groove 164 is provided on its outer surface, extending to the slit 68 in the rear section of the spring housing. Figure 36 As shown, a transverse wall 70 is provided in the spring housing, which has a central channel 71 surrounded by a flange 73 for a hook 102 of the plunger rod 90. Figure 37 and 38 As shown, the longitudinal groove 164 is designed to interact with a wedge 166 on the inner surface of the front section of the release sleeve 72. The wedge 166 of the release sleeve 72 is guided radially by the groove 164 on the spring housing 48. This aligns the release sleeve 72 with the plunger rod 90 and ensures that both plunger rod hooks 102 are activated simultaneously. The wedge 166 is designed to be long enough that it does not disengage from the groove 164 when the trigger 104 is pressed, and activation occurs. As in the previous embodiment, the wedge 166 may be provided with a wedge-shaped surface 168 to achieve a smooth user feel upon reaching the final section of the activation stroke. Because the second embodiment requires a greater penetration depth, and therefore a longer travel distance for the needle cap 36 and the release sleeve 72, the release sleeve 72 is provided with a longer safety pin 88 to ensure that the plunger rod 90 is released only when the full penetration depth has been reached.

[0054] like Figure 35 As shown, the spring housing 48 also includes two forward-pointing plates 170, and the device may be equipped with a so-called click plate 172. The click plate 172 includes flexible wings 174 that contact the rear surface of the flange of the syringe 24 to prevent the syringe 24 from clicking before activation, as the flexible wings 174 of the click plate hold the forward-pushing syringe 24 in place. Furthermore, the click plate 172 may be provided with a click tongue 176, which is positioned at a 90-degree angle to the flexible wings 174. The click tongue has the same function as the previously described tongue 156, for providing the user with information that injection is in progress. An opening 178 in the sidewall of the click plate 172 cooperates with a protrusion 180 on the spring housing 48 to hold the component in place.

[0055] The cap can also have a slightly different design, which includes flexible arms 182, such as Figure 39 As shown, the flexible arm is provided with an inwardly pointing protrusion 184, which fits into the recess 15 of the main body 12.

[0056] The device, in its basic construction, can produce a clicking sound when shaken by the user. Besides the generally wide gaps between components used to accommodate large tolerances in component manufacturing, there are two main mechanisms that can produce the clicking sound.

[0057] 1. The basic assembly without the flexible element produces a slight clicking sound from the interface between the syringe, spring housing, and syringe holder. When the syringe is seated in the syringe holder, there can be a gap of approximately 1 mm between the syringe flange and the spring housing. This gap is intentional to allow for tolerance variations in the glass flange without requiring the syringe with the flexible element to be pressed into a fixed position.

[0058] 2. When the cap has been removed, the user may hear a clicking sound from the interface between the needle cap, body, and release sleeve. Once the cap is installed, the needle cap is pushed back in to a tight contact with the release sleeve, without any additional clicking gap. However, just before use, when the cap is removed and the sterile barrier of the needle is compromised, the needle cap can move freely a few millimeters between the stop surfaces in the release sleeve and body. When the needle cap is in the locked position after use, it is in the extended position. If customer acceptance is desired, this free movement of the needle cap just a few millimeters before use can be provided to the user as an "active signal." It indicates that the device is "up" and ready for use.

[0059] It should be understood that the embodiments shown above and in the accompanying drawings are merely non-limiting examples of the present invention and can be modified in various ways within the scope of the patent claims.

Claims

1. A drug delivery device, comprising: -Main body (12); - A drug container (24) having a drug delivery component (26) disposed in the main body; - A drive unit comprising a plunger rod (90) and a drive spring (96), the drive unit being operatively connected to the drug container; - An activator, which is operatively connected to the drive unit; as well as - A safety mechanism operatively connected to the plunger rod; In the initial state of the device, the plunger rod is held in place by the tensioned drive spring, and the safety mechanism contacts the plunger rod and prevents its release. When the device is pressed against the injection site, the activator acts on the safety mechanism to move the safety mechanism away from contact with the plunger rod. The activator acts on the plunger rod to release the plunger rod, thereby causing the plunger rod to act on the drug container to deliver the drug at the injection site. The plunger rod (90) includes a plurality of flexible arms (100). The drug delivery device also includes a spring housing (48) disposed inside the main body (12). The spring housing (48) has a central channel (71) and a flange (73) disposed adjacent to the central channel (71). The plurality of flexible arms include protrusions (102) that cooperate with the flange (73) fixed in the spring housing. The safety mechanism includes a safety pin (88) located between the plurality of flexible arms (100) to prevent the release of the plunger rod. The activator includes a release sleeve (72) provided with a flange (82) and an intermediate release member (104). The flange (82) of the release sleeve is moved to act on the plunger rod to release the plunger rod.

2. The drug delivery device according to claim 1, wherein, The flange (82) of the release sleeve acts on the protrusion to bend the plurality of flexible arms to release the plunger rod.

3. The drug delivery device according to claim 1, wherein, The safety pin (88) is included in the release sleeve, the safety pin being designed to disengage from the plurality of arms of the plunger rod when the flange (82) of the release sleeve is moved to act on the protrusion of the plunger rod (90).

4. The drug delivery device according to any one of claims 2-3 further includes a needle cap (36) configured to be moved into the body (12) thereby moving the release sleeve (72).

5. The drug delivery device according to claim 4 further includes a needle cap spring (78) acting on the release sleeve (72), whereby after the device is removed from the injection site, the release sleeve and the needle cap (36) move to a forward position, wherein the needle cap covers the drug delivery member (26).

6. The drug delivery device according to claim 5, wherein, The release sleeve (72) further includes a locking feature (80) configured to lock the release sleeve (72) and the needle cap (36) in the forward position.

7. The drug delivery device according to claim 6, wherein, The locking feature (80) includes an opening. The spring housing includes flexible locking members (56, 58) arranged to bend into the opening.

8. The drug delivery device according to claim 7, wherein, The spring housing (48) is generally tubular and elongated, surrounding the drive spring (96), and is used to control the buckling of the drive spring during injection.

9. The drug delivery device according to claim 7, wherein, The spring housing (48) also includes support members (54, 174) designed to contact and support the rear surface of the drug container (24).

10. The drug delivery device according to claim 7, wherein, The spring housing (48) also includes an auditory / tactile component (172) configured to contact the drive spring (96) and slide along the drive spring (96) during injection, thereby generating auditory / tactile information for the user.

11. The drug delivery device of claim 1, further comprising a syringe holder (18) including an opening (22) surrounded by a support surface (20), wherein the body (12) is provided with an opening (16), wherein the support surface is configured to snap into the opening of the body to attach the syringe holder to the body.

12. The drug delivery device according to claim 11, wherein the syringe holder further comprises a seat (34) designed to support a flange (32) at the rear end of the drug container (24).

13. The drug delivery device according to claim 1, further comprising a cap (126) attachable to the front end of the device, the cap including flexible hooks (140, 142) engaging a needle cover (29) covering the drug delivery member, wherein removal of the cap removes the needle cover.

14. The drug delivery device according to claim 13, wherein, The cap (126) also includes a flexible hook (144) at the front region of the cap for retaining the needle cover (29) after removal.

15. The drug delivery device according to claim 13 or 14, wherein, The cap (126) is provided with flexible members (134, 182, 184) that cooperate with the body (12) for releasably holding the cap to the body.

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