Drug delivery device

Abstract

The present invention provides a drive unit including a body (12), a medicament container (24) with a medicament delivery member (26) disposed in the body (12), a plunger rod (90) and a drive spring (96), the drive unit being operably connected to the medicament container (24), an activator (36, 72, 104) operably connected to the drive unit, and a safety mechanism (88) operably connected to the plunger rod (90), wherein in an initial state of the device, the plunger rod (90) is held by the drive spring (96) in a tensioned state, and the safety mechanism The safety mechanism (88) contacts the plunger rod (90) to prevent the plunger rod (90) from being released, and 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 the activator (88) acts on the plunger rod (90) to release it, causing the plunger rod (90) to act on the drug container (24) at the injection site to deliver the drug.

Description

[Technical Field]

[0001] The present invention relates to a drug delivery device, and in particular to an auto-injector. [Background Art]

[0002] Drug delivery devices have been commercially available as self-administration products for drugs for many years. Many of these are designed as auto-injectors with the aim of minimizing the number of procedures an end user needs to perform to initiate an injection.

[0003] U.S. Patent No. 3,797,489 discloses an auto-injector provided with a pre-tensioned drive spring operably connected to a plunger rod. To activate the device, the safety cap with a safety pin is removed, and the device is pressed against the injection site. Then, when the user presses the button at the rear end of the device, the syringe with the needle moves forward, and penetration is performed. When the plunger rod is released, injection is performed. When the device is removed after injection, the return spring is tensioned such that the syringe and the needle are retracted back into the injector.

[0004] U.S. Patent No. 5,681,291 discloses an auto-injector having a needle cover movable within a device housing. When the injector is pressed against the injection site, the needle cover moves rearward, and penetration is performed manually. The movement of the needle cover further causes actuation of the drive spring acting on the plunger rod to perform the injection. When the device is removed from the injection site, a spring pushes the needle cover to a position covering the needle, where the needle cover is locked.

[0005] Although many of these devices currently on the market have sufficient functionality and robustness, there is always room for improvement. [Summary of the Invention]

[0006] An object of the present invention is to provide a drug delivery device with high robustness, highly reliable functionality and safety functions.

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

[0008] According to the main embodiment, the drug delivery device is provided having a housing, a drug container equipped with a drug delivery member disposed within the housing, a plunger rod, and a drive unit equipped with a drive spring.

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

[0010] In the initial state of the device, the plunger rod is held in place by a taut drive spring, and a safety mechanism contacts the plunger rod to prevent release, thus preventing the device from operating unintentionally.

[0011] When the device is pressed against the injection site, the activator acts on the safety mechanism, which moves the safety mechanism to release contact with the plunger rod and activate the device.

[0012] Furthermore, the activator acts on the plunger rod to release it, causing the plunger rod to act on the drug container to deliver the drug to the injection site. A clear activation point is ensured because the activator actively acts on the plunger rod (directly or via an intermediate element) to release it. The reliability of the release system can be improved because the operation does not rely on components sliding on a surface that provides frictional resistance under the influence of the force of the drive spring.

[0013] Therefore, when the device is used for injection, the activator functions to release the safety mechanism and initiate the injection.

[0014] In another embodiment, the activator may include a release sleeve with a release member that moves in contact with the plunger rod to release the plunger rod. The release sleeve is a robust and functional design when the release member is used.

[0015] The drug delivery device may further include a needle cover designed to move within the main body and a movable release sleeve. Thus, the needle cover and the release sleeve cooperate for the operation of the device.

[0016] Furthermore, the plunger rod may be provided with a flexible arm, which may have a projection that cooperates with a ledge fixed to the device, and the release member pushes the projection to bend the arm and release the plunger rod. In this regard, the safety mechanism may include a safety pin that contacts the flexible arm to prevent the release of the plunger rod. The safety pin prevents the device from malfunctioning during transport or if the user drops the device.

[0017] In a further embodiment, a safety pin may be contained within the release sleeve, and when the release member is moved and contacts and pushes a projection of the plunger rod, the safety pin may be released from the arm of the plunger rod. This design provides the release sleeve with several functions.

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

[0019] In a further embodiment, the device may be equipped with a needle cover spring acting on a release sleeve, thereby causing the release sleeve and needle cover to move to a forward position such that the needle cover covers the drug delivery member after the device is removed from the injection site. In this case as well, the release sleeve and needle cover work together to cover the needle after injection.

[0020] To ensure safety against accidental needle punctures, the release sleeve may further include a locking member designed to lock the release sleeve and needle cover in a forward position. Here again, the release sleeve is designed with several functions. In this regard, the locking member may include an opening and further include a spring housing attached to the body, and the spring housing may include a flexible locking member positioned to bend and enter the opening.

[0021] In a further embodiment, the spring housing may be designed in an elongated, substantially cylindrical shape to surround the drive spring to control buckling of the drive spring during injection, thereby ensuring the reliability of the device's function. The spring housing may have a central passage, with a ledge provided adjacent to the central passage. The spring housing may further include a support member designed to contact and support the rear surface of the syringe. The spring housing may further include an audible / tactile member designed to contact the drive spring and slide along the drive spring during injection, thereby generating audible / tactile information for the user. The spring housing is also designed to have many functions.

[0022] In a further embodiment, the apparatus may include a syringe holder, the syringe holder may have an opening surrounded by a support surface, and the body may be designed to have an opening, with the support surface fitting into the opening of the body, thereby attaching the syringe holder to the body. The syringe holder may further include a seat designed to support the flange at the rear end of the syringe.

[0023] The drug delivery device may further include a cap that can be attached to the front end of the device, the cap including a flexible hook that engages with a needle shield covering the drug delivery member, and the needle shield may be removed by removing the cap. In this regard, the cap may further include a flexible hook in the front region of the cap to hold the needle shield after removal.

[0024] These and other aspects of the present invention, as well as the advantages of the present invention, will become apparent from the following detailed description of the present invention and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In the following detailed description of the present invention, reference is made to the accompanying drawings. [Figure 1] It is a cross-sectional view of a first embodiment of a drug delivery device according to the present invention. [Figure 2] It is a cross-sectional view of a first embodiment of a drug delivery device according to the present invention. [Figure 3] It is a view showing different constituent members and elements included in the apparatus of Figs. 1 to 2. [Figure 4] It is a view showing different constituent members and elements included in the apparatus of Figs. 1 to 2. [Figure 5] It is a view showing different constituent members and elements included in the apparatus of Figs. 1 to 2. [Figure 6] It is a view showing different constituent members and elements included in the apparatus of Figs. 1 to 2. [Figure 7] It is a view showing different constituent members and elements included in the apparatus of Figs. 1 to 2. [Figure 8] It is a view showing different constituent members and elements included in the apparatus of Figs. 1 to 2. [Figure 9] It is a view showing different constituent members and elements included in the apparatus of Figs. 1 to 2. [Figure 10] It is a view showing different constituent members and elements included in the apparatus of Figs. 1 to 2. [Figure 11] It is a view showing different constituent members and elements included in the apparatus of Figs. 1 to 2. [Figure 12] It is a view showing different constituent members and elements included in the apparatus of Figs. 1 to 2. [Figure 13] It is a view showing different constituent members and elements included in the apparatus of Figs. 1 to 2. [Figure 14] It is a view showing different constituent members and elements included in the apparatus of Figs. 1 to 2. [Figure 15]Figures 1 and 2 show the different components and elements included in the apparatus. [Figure 16] Figures 1 and 2 show the different components and elements included in the apparatus. [Figure 17] Figures 1 and 2 show the different components and elements included in the apparatus. [Figure 18] Figures 1 and 2 show the different components and elements included in the apparatus. [Figure 19] Figures 1 and 2 show the different components and elements included in the apparatus. [Figure 20] Figures 1 and 2 show the different components and elements included in the apparatus. [Figure 21] Figures 1 and 2 show the different components and elements included in the apparatus. [Figure 22] This figure shows the different functional states of the devices in Figures 1 and 2. [Figure 23] This figure shows the different functional states of the devices in Figures 1 and 2. [Figure 24] This figure shows the different functional states of the devices in Figures 1 and 2. [Figure 25] This figure shows the different functional states of the devices in Figures 1 and 2. [Figure 26] This figure shows the different functional states of the devices in Figures 1 and 2. [Figure 27] This figure shows the different functional states of the devices in Figures 1 and 2. [Figure 28] This figure shows the different functional states of the devices in Figures 1 and 2. [Figure 29] This figure shows the different functional states of the devices in Figures 1 and 2. [Figure 30] This figure shows the different functional states of the devices in Figures 1 and 2. [Figure 31] This is a cross-sectional view of a second embodiment of a drug delivery device according to the present invention. [Figure 32] This is a cross-sectional view of a second embodiment of a drug delivery device according to the present invention. [Figure 33] Figures 31-32 show the different components and elements included in the apparatus. [Figure 34] Figures 31-32 show the different components and elements included in the apparatus. [Figure 35] Figures 31-32 show the different components and elements included in the apparatus. [Figure 36] Figures 31-32 show the different components and elements included in the apparatus. [Figure 37] Figures 31-32 show the different components and elements included in the apparatus. [Figure 38] Figures 31-32 show the different components and elements included in the apparatus. [Figure 39] Figures 31-32 show the different components and elements included in the apparatus. [Modes for carrying out the invention]

[0026] definition The "front" side of the device – this refers to the side of the device where the needle emerges during injection. "Rear" side - the opposite side from where the needle comes out during injection.

[0027] A first embodiment of the drug delivery device 10 is shown in Figures 1 to 30. The first embodiment is designed for subcutaneous injection of a small amount of drug, approximately 1 ml. As shown in Figures 3 and 4, it includes an elongated, substantially cylindrical body 12. The outer surface of the body 12 is provided with wings 14. The outer surface of the body 12 is also designed to hold a label containing relevant information. The outer wings 14 of the body 12 function as both an anti-roll and a handle for the user. A recess 15 is provided in front of the wings. The body 12 further has an opening 16. The inner surface of the body 12 further has longitudinally extending guide ledges 17. The inner surface of the body 12 also has longitudinally extending guide grooves 19, which are provided with rearward-facing stop ledges 21.

[0028] As shown in Figures 5 and 6, a syringe holder 18 is mounted inside the main body 12. The syringe holder 18 has an outward-extending wall 20, which forms an opening into the interior of the syringe holder 18, and together with the opening 16 of the main body 12, creates an inspection window 22. The wall 20 is designed to fit into the opening 16, and the syringe holder 18 is also designed with a flexible portion that allows the wall to be compressed inward during assembly and fitted into the opening 16. This secures the two components together, as shown in Figure 6.

[0029] A syringe holder 18 can house a syringe 24, preferably made of glass, equipped with an injection needle 26 and a movable stopper 28. Before use, the needle is preferably protected and kept sterile by a rigid needle shield (RNS) 29. The syringe and its contents can be viewed through an inspection window opening 22. The syringe holder 18 is designed with a guide section 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 ensures a specified length dimension with tolerances. The surface of the seat 34 of the syringe holder 18 is designed to minimize glass breakage by being smooth and having no single contact points. A rubber portion may be attached to the seat 34 by 2K molding or as an O-ring assembly to further smooth the contact surface and prevent breakage of the glass flange. Furthermore, the seat portion 34 of the syringe holder 18 is designed for the "cut flange" of the syringe, which is positioned in the rotational direction of the flange. However, syringes with a "small round flange" can also be fitted to the syringe holder. The small round flange has the advantage of being stronger and having a lower risk of glass breakage. In addition, the outer surface of the seat portion 34 is provided with a flat surface and projections 35 on both sides for guide support (described later).

[0030] As shown in Figure 7, the device further includes a needle cover 36, which is part of the device's activator. The needle cover 36 is substantially cylindrical and positioned to extend a certain distance from the front end of the main body 12. The rear end of the needle cover 36 has two legs 38 that extend backward. The opening 40 at the front end of the needle cover 36 is made small enough to adequately prevent a sphere with a diameter of 12 mm from passing through. This is a standard requirement to prevent accidents such as finger pricks. The legs of the needle cover 36 are designed to fit into guide grooves 19 of the main body 12, and a stop ledge 21 interacts with the forward-facing surface 42 of the legs 38 to restrict the forward movement of the needle cover 36 and prevent it from falling off. An opening 46 is located on the side of the needle cover 36, allowing the needle cover to move around an inspection window wall 20 formed in the syringe holder 18. The inner surface of the leg portion 38 of the needle cover is flat, and the width of the leg portion 38 is such that it is also guided by the projection 35 of the syringe holder 18. This makes it possible to manufacture the leg portion 38 with a greater thickness, while the syringe holder 18 still has an edge that guides the rotation of the syringe flange, which is advantageous from a manufacturing standpoint.

[0031] As shown in Figures 8 and 9, a substantially cylindrical spring housing 48 is further positioned inside the main body. A guide plate 50 is positioned at its front end, and the guide plate 50 is provided with an outwardly extending projection 52 that fits between guide ledges 17 on the inner surface of the main body 12. This allows the spring housing 48 to move axially and guides the spring housing 48 in the rotational direction relative to the main body 12. The outer surface of the guide plate 50 is further designed with a flat notch 53 designed to guide the legs 38 of the needle cover 36. The guide plate 50 has a forward-extending structure 54 that contacts the rear surface of the flange of the syringe 24, holds the syringe 24 in its axial position, and prevents the syringe 24 from moving only a short distance in the rearward direction. The structure 54 may be a tubular body with a notch 55, as seen in Figure 8. Alternatively, it may have a projecting rib that extends forward and ends slightly before the flange of the syringe 24. The purpose of the structure 54 is to hold the syringe in place if it slides a certain distance backward from the syringe holder surface 34, and to prevent the flange region from receiving a large impact due to the acceleration and cessation of the syringe's movement.

[0032] The front region of the spring housing 48 is further provided with a forward-extending flexible arm 56, and the free end of the flexible arm 56 is provided with an outward-extending lockout hook 58. Its function is described below. The outer surface of the spring housing has a longitudinally extending plane 60. The rear region of the spring housing is designed with two longitudinal slits 62, which create two flexible arms 64. An outward-extending wedge 66 is positioned at the rear end of the arms 64. An elongated slit 68 is positioned in front of the wedge 66. A lateral wall 70 is positioned inside the spring housing in the region where the slit 68 terminates in the forward direction. As shown in Figure 9, a central passage 71 is provided in the lateral wall 70, and a ledge 73 is formed on the lateral wall 70 between the passage 71 and the slit 68.

[0033] As shown in Figures 10-12, the device further comprises a release sleeve 72, which is part of the activator, in addition to the device's safety mechanism. The front of the release sleeve 72 is substantially tubular and has a front plate 74 that interacts with the end faces of the legs 38 of the needle cover 36, so that when the needle cover 36 is moved backward, the release sleeve 72 also moves. As shown in Figure 1, the release sleeve 72 has a spring mounting seat 76 for the needle cover spring 78. The needle cover spring 78, along with the design of the device's components, must be rigid enough to function as a transport safety mechanism that keeps the device in a safe state, not activating even when vibrations or shocks occur during transport. The mounting seat 76 is deep enough to prevent the ends of the coil wire from being pushed out of the spring's diameter and hitting or interfering with the body 12 during transport. The spring mounting seat 76 has the largest diameter of the release sleeve components, but is small enough to avoid contact with the inside of the body 12.

[0034] The inner surface of the main body 12 is a portion that guides the needle cover spring 78 radially when the needle cover spring 78 buckles away from its ideal axial position. The outer diameter of the front of the release sleeve 72 acts as an inner guide for the needle cover spring 78 to prevent buckling. An opening 80 is located at the rear of the front plate 74. A notch 81 is formed on the outer surface of the front plate, into which the guide ledge 17 of the main body 12 fits, locking the components together in the rotational direction, but allowing axial movement of the release sleeve 72 relative to the main body 12. The inner surface of the release sleeve 72 is further provided with a ledge 82 that is substantially flat and designed to slide against the plane 60 of the spring housing 48. A wedge-shaped surface 83 is provided at the rear end of the ledge 82. Two elongated arms 84 are designed at the rear end of the release sleeve 72. A beam 86 or bridge extending laterally is provided between the arms 84. A slender safety pin 88 extending forward is provided on the forward-facing surface of the beam 86.

[0035] As shown in Figure 13, the device is further provided with a plunger rod 90, which has a solid or hollow elongated cylindrical body with an enlarged portion 92 at its front end. As shown in Figure 1, a groove is formed on the rear surface of the enlarged portion as a mounting seat 94 for the drive spring 96. This prevents the end of the steel wire of the drive spring from sliding radially out and contacting the inner wall of the glass syringe 24. An elongated slit 98 is located at the rear of the plunger rod 90, forming two flexible arms 100. The slit 98 has a width approximately corresponding to the thickness of the safety pin 88. The free ends of the arms 100 are provided with outwardly extending projections or hooks 102. The front end surface of the hook 102 is formed as a ledge that cooperates with the ledge 73 of the spring housing, as will be described later. The plunger rod 90 is surrounded by a drive spring 96 located between the mounting seat 94 of the plunger rod and the forward-facing surface of the side wall 70 of the spring housing 48.

[0036] As shown in Figure 14, the device also includes a braking member 104, which is part of the device's activator. The braking member 104 includes a cylindrical body 106 having forward-facing legs 108, the free ends of which are provided with outward-facing ledges 110. The braking member is positioned such that the ledge 110 in its initial position contacts the outer surface of the plunger rod hook 102.

[0037] As shown in Figure 15, the device is further provided with an end cap 112, which has a substantially tubular body 114 and a rear end plate 116 attached to and covering the rear end of the body 12. Attachment is made by a projection 118 on the outer surface of the body 114 engaging with a notch 120 at the rear end of the body. The user can use the end cap 112 as a gripping component when using the device, depending on their preferred grip. The end cap 112 has a rear outer surface that clearly indicates it is closed and not the needle side of the device, compared to the needle cover side of the device. The outer surface of the body 114 of the end cap 112 is provided with an axially outward projection 122 that fits between the guide ledges 17 of the body 12. The projection 122 prevents the end cap 112 from rotating if the user attempts to twist the rear end cap 112 of the device. The end cap 112 has a forward-facing spring mounting seat 124 for the needle cover spring 78. The mounting seat 124 is deep enough to prevent the end of the coil wire from being pushed inward into the diameter of the spring and from hitting or interfering with the release sleeve 72 during the injection stroke. Furthermore, the inner surface of the end cap 112 acts as a rearward stopper for the braking member 104. The end cap 112 further has a rearward-facing ledge 125 on which the ledge 66 of the spring housing 48 rests, and in that position the rear end face of the spring housing 48 is in contact with the inner surface of the end cap 112. This fixes the spring housing 48 in place so that it does not move.

[0038] The roughly cylindrical cap 126 shown in Figures 16-18 is designed to be attached to the front end of the device as shown in Figure 1. The cap may have an opening 128 on its side, allowing the inspection window of the body to be used if the drug is not light-sensitive and the user wants to inspect the drug before removing the cap 126. Alternatively, the cap 126 may be designed to extend over the inspection window 22 to block UV light that could degrade the drug in the syringe 24. The cap 126 has an end face 130 with a small central passage 132. The cap 126 has an inner projection 134 that interacts with a recess 15 on the outer surface of the body 12 (see Figure 1). In this regard, the cap is designed so that the cap and projection can flex radially in and out of the recess 15. Furthermore, the cap 126 has wings 136 on the outside that serve both as anti-roll and gripping functions. The cap 126 has an elongated opening 138 behind the projection 134 that interacts with the wing portion 14 on the body 12. This prevents the cap 126 from rotating in the initial stage of withdrawal, in case there is a risk that the rubber of the RNS 29 will be gouged by the needle 26 of the syringe 24 if it rotates in contact with the needle 26. The cap 126 has an inner semicircular leg 140 with an inward-facing hook 142 that hooks around the trailing edge of the RNS 29, as seen in Figure 1, to grip the RNS 29 and pull it away from the needle 26 when the cap is removed. The hook 142 also prevents the RNS 29 from falling rearward from the cap 126. A flexible arm 144 in the front region of the cap 126, adjacent to the passage 132, prevents the RNS 29 from falling forward from the cap 126. The inner rib 146 of the cap 126 abuts against the front end surface of the main body 12, preventing the cap 126 from being excessively pressed against the outside of the main body 12.

[0039] The device may further include a signaling member 150 that can inform the user of the timing of the device's operation during injection. The signaling member 150 comprises a ring-shaped body 152 (Figure 19) positioned to be press-fitted into the structure 54 at the front end of the spring housing 48, as shown in Figure 20. The body 152 may have a notch 154 on its inner surface, forming a lock washer function. The body is provided with a tongue portion 156 that is formed to be inclined inward toward the center of the body 152. The end of the tongue portion 156 is formed to contact the coil of the drive spring 96, as shown in Figure 20. The signaling member 150 may be made of metal or a fairly rigid plastic material.

[0040] Figure 21 shows a display member in the shape of a sheath or sleeve film 158, which may be a thin plastic tube such as a drinking straw, and is attached to the front end of the plunger rod 90 and the drive spring 96. Preferably, the sleeve film 158 is attached only to the front end of the plunger rod 90, for example, by snap fitting, press fitting, or adhesive. The signal sleeve may also be positioned between the signal member 150 and the drive spring such that the rear of the coil is covered but the front is not. This indicates to the user that the signal member contacts the coil only at the end of the injection stroke, generates a signal only at the end of injection, and allows the device to be removed.

[0041] The complete device is intended to function as follows (Figures 22-30). The device is shown without the cap and body, sometimes in cross-sectional views, to improve the visibility of the mechanism.

[0042] Once the device is assembled, the drive spring 96 is taut around the plunger rod 90. The plunger rod 90 is held in a non-operating position with its hook 102 engaged with the ledge 73 of the spring housing 48. The flexible arms 100 of the plunger rod 90 are prevented from moving radially toward each other by safety pins 88 located in the slit 98 in Figure 22. The safety pins 88 ensure that the device does not accidentally operate during storage, transport, or handling before use. Furthermore, the beam 86 of the release sleeve 72 is positioned to rest on the rear end of the plunger rod 90 (Figure 23). This ensures that the release sleeve 72 cannot move forward from this position at any given time. The needle cover 36 is in its extended position, covering the needle 26, due to the force of the needle cover spring 78.

[0043] To use the device, the cap 126 is removed as described above, thereby detaching the RNS 29 from the needle 26. Once the cap 126 is removed, the needle cover 36 can move freely a short distance forward. The needle cover 36 may rattle between the release sleeve 72 blocking it in the rearward direction and the structure 21 of the main body 12 blocking it in the forward direction. This feature is intentional, as the short, free "rattling" movement of the needle cover 36 before injection when the cap 126 is removed signals that the device is operational and ready for use. When the device is in use, the gap described above narrows.

[0044] The device is positioned relative to the injection site in the body and pressed against the injection site, causing the needle 26 to penetrate. This movement pushes the needle cover 36 into the housing against the force of the needle cover spring 78, and the legs 38 of the needle cover 36 act on the front plate 74, so that the release sleeve 72 is sequentially pushed backward (Figure 24). The movement of the release sleeve 72 first removes the safety pin 88 from its initial position in the slit 98 between the plunger rod hooks 102 (Figure 25). The safety pin 88 is designed to leave the plunger rod 90 just before the device is activated. Note that if the plunger rod hooks 102 are attached by the design of the contact surface between the hooks 102 and the ledge 73, they may still be caught on the ledge 73. The ledge 82 of the release sleeve 72 comes into contact with the braking ledge 110 (Figure 26), and as the release sleeve moves further, the ledge 82 of the release sleeve 72 pushes the leg portion 108 of the braking member 104 radially toward the center (Figure 27).

[0045] As described above, the ledge 82 may be provided with a wedge-shaped surface 83 to provide a smooth user feel when reaching the final part of the operating stroke. However, this results in a "starting point" depending on the geometric angle. The ledge 82 guides the release sleeve 72 radially, ensuring that tolerances and misalignments of the operating mechanism are kept to a minimum.

[0046] As the braking leg portion 108 moves radially, the hook 102 of the plunger rod 90 is pushed out from the edge to which it is attached (Figure 28). This causes the drive spring 96 to move the plunger rod 90, thus activating the injection.

[0047] The contact surface between the plunger rod hook 102 and the ledge 73 of the spring housing 48 is preferably designed to have a chamfered surface so that the hook 102 can catch on the ledge 73 even when the safety pin 88 is removed. This creates an obvious starting point where the plunger rod hook 102 is mechanically pushed away from the ledge 73 by the braking member 104 and the release sleeve 72. Thus, the starting is successful without relying on components sliding on surfaces that create frictional resistance under the influence of the force of the drive spring. However, if it is desired to minimize the force at the end of the stroke of the needle cover 36, the contact surface between the plunger rod hook 102 and the ledge 73 of the spring housing 48 may be designed to have a chamfered surface in the opposite direction so that the hook 102 can detach from the ledge 73 as soon as the safety pin 88 is removed. On the other hand, in this configuration, the plunger rod hook 102 is tightening the safety pin 88, and frictional resistance is created when it is pulled out, so a greater force is required earlier in the starting process. The release sleeve 72 and the braking member 104 push the hook 102 together even if they cannot be released on their own, resulting in an operating system that anyone can use.

[0048] The spring housing 48 guides the outer diameter of the drive spring 96 when the device is activated and the drive spring 96 expands. At this point, the rear end of the drive spring 96 is no longer radially supported by the plunger rod 90. The support from the spring housing 48 prevents buckling of the long drive spring 96. As the plunger rod 90 moves, the stopper 28 in the syringe 24 moves, and the prescribed amount of drug is released through the needle 26. If a signal member 150 is used during injection, its tongue 156 interacts with the spring coil of the drive spring 96, producing a distinct clicking sound as it passes over the spring wire. The frequency of continuous clicking changes during the injection stroke due to two factors: the decrease in the force of the drive spring 96 as the drive spring 96 expands, thus decreasing the speed at which the plunger rod 90 moves, and the increase in the spring coil pitch as the distance the plunger rod 90 travels increases.

[0049] During and after injection, the plunger rod 90 can be seen through the inspection 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, may be used as a signal to the user to indicate the completion of injection. If a sleeve film is used, the colored sleeve film can be seen in the inspection window after use, partially or completely covering the window. The signal sleeve film 170 partially or completely hides the coil of the drive spring 96 from view through the inspection window after use of the device. The signal sleeve film 170 has the optional function of preventing the drive spring 96 from contacting the inner glass wall of the syringe 24.

[0050] When the device is removed from the injection site, the needle cover spring 78 pushes the release sleeve 72 forward, which in turn pushes the needle cover 36 forward. As the plunger rod 90 moves away from the inner wall 70, the release sleeve 72 moves further forward and can reach the lockout position. With the needle cover spring 78 pushing the release sleeve 72 forward, the arm 56 bends inward, and the front end of the release sleeve 72 moves over the lockout hook 58 of the spring housing 48. The outwardly protruding lockout hook 58 enters the opening 80 of the release sleeve. As a result, the needle cover 36 is locked in the extended position by the release sleeve 72 via the legs 38 of the needle cover 36 (Figures 29 and 30).

[0051] Figures 31-39 show a second embodiment of the drug delivery device. Many of the components are the same, and the function of the second embodiment is the same as that of the first embodiment, so it will not be described in detail again. However, the differences will be highlighted. The second embodiment is designed for intramuscular injection, and its dose may be greater 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 ledge 160 is positioned on the inner surface to provide a stop ledge for the needle cover 36 in Figure 33. Furthermore, the syringe holder 18 is provided with a guide portion 162 at its rear end for guiding the syringe flange (Figure 34). The syringe flange may be a flange with a notched portion.

[0052] The spring housing 48 of the second embodiment has a somewhat different design. For example, a longitudinal groove 164 is provided on its outer surface to a slit 68 in the rear portion of the spring housing in Figure 35. A transverse wall 70 is provided within the spring housing, having a central passage 71 surrounded by a ledge 73 for the hook 102 of the plunger rod 90 (Figure 36). The longitudinal groove 164 is designed to interact with a wedge 166 on the inner surface of the front portion of the release sleeve 72 (Figures 37 and 38). The wedge 166 of the release sleeve 72 is radially guided by the groove 164 of the spring housing 48. This ensures that the release sleeve 72 is centered relative to the plunger rod 90 and that both plunger rod hooks 102 actuate simultaneously. The wedge 166 is designed to be long enough so that it does not move away from the groove 164 when the braking member 104 is pressed and actuated. Similar to the previous embodiment, the wedge 166 is provided with a wedge-shaped surface 168 to smooth the user feel when reaching the final part of the operating stroke. The second embodiment requires a greater penetration depth and, consequently, a longer distance traveled by the needle cover 36 and the release sleeve 72, so the release sleeve 72 is provided with a longer safety pin 88 to ensure that it is released only when the plunger rod 90 has reached its full penetration depth.

[0053] The spring housing 48 is further provided with two forward-facing plates 170, and the device may be provided with a so-called click seat 172 (Figure 35). The click seat 172 has a flexible wing portion 174 that is in contact with the rear surface of the flange of the syringe 24. This allows the flexible wing portion 174 of the click seat to hold the syringe 24 as it is pushed forward, preventing the syringe 24 from rattling in the device before operation. Furthermore, the click seat 172 may be provided with a click tongue portion 176 positioned at a 90-degree angle to the opposite side of the flexible wing portion 174. The click tongue portion, like the tongue portion 156 described above, has the function of providing the user with information that injection is in progress. An opening 178 in the side wall of the click seat 172 cooperates with a projection 180 of the spring housing 48 to hold the components in place.

[0054] The cap may also have a somewhat different design, including a flexible arm portion 182 (Figure 39) having an inwardly oriented projection 184 that fits into a recess 15 of the main body 12.

[0055] Basic devices may rattle when shaken by the user. Aside from the typical wide gaps between components to accommodate large tolerances in manufacturing, there are two main mechanisms that generate rattle. 1. Basic devices without a flexible sheet may have slight rattle at the interface between the syringe, spring housing, and syringe holder. When the syringe is seated in the syringe holder seat, there may be a gap of approximately 1 mm between the syringe flange and the spring housing. This gap is intentionally provided to allow for tolerance variations in the glass flange, but it is not necessary to tighten the syringe to a fixed position with a flexible member. 2. When the cap is removed, rattling noises may be heard from the interface between the needle cover, the main body, and the release sleeve. As long as the cap is attached, the needle cover is pushed back and tightly fits against the release sleeve, leaving no gaps that would cause extra rattling. However, when the cap is removed immediately before use and the sterile barrier of the needle is broken, the needle cover can move a few millimeters freely between the release sleeve and the stop surface inside the main body, which is the extended position when the needle cover is locked after use. If customer acceptance needs to be motivated, the fact that the needle cover can move a few millimeters freely immediately before use can be promoted as a "positive signal" to the user, indicating that the device is "set" and ready to use.

[0056] The embodiments described above and shown in the drawings should be considered only non-limiting examples of the present invention and should be understood to be modifiable in many ways within the scope of the claims.

Claims

1. The main body (12) and A drug container (24) equipped with a drug delivery member (26) arranged on the main body, A drive unit including a plunger rod (90) and a drive spring (96), the drive unit being operably connected to the drug container, An activator (36, 72, 104) operably connected to the drive unit, The plunger rod is operably connected to a safety mechanism (88), In the initial state of the device, the plunger rod is held by the drive spring under tension, and the safety mechanism contacts the plunger rod to prevent its release. When the device is pressed against the injection site, the activator acts on the safety mechanism, moving the safety mechanism so that it does not come into contact with the plunger rod. The activator acts on the plunger rod to release it, causing the plunger rod to act on the drug container at the injection site to deliver the drug. Drug delivery device.

2. The drug delivery device according to claim 1, wherein the activator comprises a release sleeve (72) provided with release members (82, 104) that move to act on the plunger rod to release the plunger rod.

3. The drug delivery device according to claim 2, wherein the plunger rod (90) comprises a flexible arm (100), the flexible arm comprises a projection (102) that cooperates with a ledge (73) fixed within the device, and the release member (82) acts on the projection to bend the flexible arm and release the plunger rod.

4. The drug delivery device according to claim 3, wherein the safety mechanism includes a safety pin (88) between it and the flexible arm (100) to prevent the release of the plunger rod.

5. The drug delivery device according to claim 4, wherein the safety pin (88) is contained within the release sleeve and is designed so that when the release member (82) is moved and acts on the protruding portion of the plunger rod (90), the safety pin moves away from contact with the arm portion of the plunger rod.

6. The drug delivery device according to any one of claims 3 to 5, further comprising an intermediate release member (104) that contacts the protruding portion of the plunger rod, wherein the release member (82) of the release sleeve (72) presses the intermediate release member for releasing the plunger rod (90).

7. The drug delivery device according to any one of claims 3 to 6, further comprising a needle cover (36) inserted into the main body (12) and configured to move the release sleeve.

8. The drug delivery device according to claim 7, further comprising a needle cover spring (78) acting on the release sleeve (72), wherein, when the needle cover spring acts on the release sleeve, the release sleeve and the needle cover (36) move to a forward position with the needle cover covering the drug delivery member (26) after the device has been removed from the injection site.

9. The drug delivery device according to claim 8, further comprising a locking function (80) configured to lock the release sleeve (72) and the needle cover (36) in a forward position.

10. The drug delivery device according to claim 9, wherein the locking function (80) includes an opening, further includes a spring housing (48) attached to the main body, and includes flexible locking members (56, 58) arranged such that the spring housing bends to enter the opening.

11. The drug delivery device according to claim 10, wherein the spring housing (48) is elongated and substantially cylindrical, and surrounds the drive spring (96) to control the buckling of the drive spring during injection.

12. The drug delivery device according to claim 10 or 11, wherein the spring housing (48) comprises a central passage (71) and the ledge (73) is provided adjacent to the central passage.

13. The drug delivery device according to any one of claims 10 to 12, further comprising a support member (54, 174) designed to contact and support the rear surface of the drug container (24) of the spring housing (48).

14. The drug delivery device according to any one of claims 10 to 13, further comprising an audible / tactile member (172) configured to contact and slide with the drive spring (96) during injection to create audible / tactile information for the user.

15. A drug delivery device according to any one of claims 1 to 14, further comprising a syringe holder (18), wherein the syringe holder has an opening (22) surrounded by a support surface (20), the main body (12) is provided with an opening (16), and the support surface is fitted into the opening of the main body so that the syringe holder is attached to the main body.

16. The drug delivery device according to claim 15, further comprising a seat (34) designed to support a flange (32) at the rear end of the drug container (24) of the syringe holder.

17. A drug delivery device according to any one of claims 1 to 16, further comprising a cap (126) that can be attached to the front end of the device, wherein the cap is provided with flexible hooks (140, 142) that engage with a needle shield (29) covering the drug delivery member, and the needle shield is removed when the cap is removed.

18. The drug delivery device according to claim 17, wherein the cap (126) further comprises a flexible hook (144) in the front region of the cap for holding the needle shield (29) after removal.

19. The drug delivery device according to claim 17 or 18, wherein the cap (126) comprises flexible members (134, 182, 184) that cooperate with the main body (12) to releasably hold the cap in the main body.

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