Power unit subassembly
By designing the connection mechanism between the housing, locking ring, and activation ring in the power unit sub-assembly, the locking problem of the drug delivery device was solved, achieving the effect of preventing reactivation after use and ensuring the safety and effectiveness of drug delivery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHL MEDICAL AG
- Filing Date
- 2021-12-10
- Publication Date
- 2026-06-09
AI Technical Summary
There is room for improvement in the locking mechanisms of existing drug delivery devices, especially in preventing premature drug delivery.
A power unit sub-assembly was designed, including a housing, a sliding locking ring, and an activation ring. The axial movement of the activation ring is achieved through a connecting mechanism and a locking mechanism, ensuring that the drug delivery device cannot be reactivated after use.
It provides a clear activation point to prevent the drug delivery device from being reused after use, ensuring the safe and effective delivery of drugs.
Smart Images
Figure CN116897062B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a power unit subassembly, and more particularly to a power unit subassembly having a locking mechanism. Background Technology
[0002] Drug delivery devices, such as autoinjectors, may include locking mechanisms to prevent premature drug delivery. The applicant has recognized that improvements can be made to these existing locking mechanisms. Summary of the Invention
[0003] This invention is defined by the appended claims, which are hereby referred to for understanding.
[0004] In this disclosure, the term "distal direction" refers to the direction away from the dose delivery site during use of the drug delivery device. The term "distal portion / distal end" refers to the portion / end of the delivery device or its components that is furthest from the drug delivery site when the drug delivery device is in use. Correspondingly, the term "proximal direction" refers to the direction towards the dose delivery site during use of the drug delivery device. The term "proximal portion / proximal end" refers to the portion / end of the delivery device or its components that is closest to the drug delivery site when the drug delivery device is in use.
[0005] In addition, the terms “longitudinal,” “axial,” or their grammatical variations refer to the direction in which the device or its components extend from the proximal end to the distal end, typically along the longest extension direction of the device and / or component.
[0006] Similarly, the term "horizontal" or its grammatical variations refer to a direction roughly perpendicular to the longitudinal direction.
[0007] One aspect of the invention relates to a power unit subassembly for a pharmaceutical delivery device, the power unit subassembly extending axially from a proximal end to a distal end along an axis, the power unit subassembly including a housing extending from the distal end of the power unit subassembly; a locking ring slidable axially relative to the housing; an activation ring slidable axially relative to the housing and relative to the locking ring, wherein the locking ring is arranged closer to the distal end of the power unit subassembly than the activation ring; a connection mechanism for connecting the activation ring to the locking ring during use, the connection mechanism including a connector on the activation ring and a corresponding connector on the locking ring; and a locking mechanism for locking the power unit subassembly after use, the locking mechanism including a distally facing surface on the locking ring and a corresponding proximal facing surface on the housing. This provides a power unit subassembly that can have a clear activation point and be activated by axial movement of the activation ring. This provides a power unit subassembly including a lock that can prevent the used device from being reused.
[0008] Optionally, the power unit subassembly includes a spring disposed between the housing and the activation ring. Optionally, the housing includes a flexible arm extending proximally, wherein a proximally facing surface of the housing rests on the arm. Optionally, the flexible arm is flexible in a radial direction relative to an axis. Optionally, the housing, the activation ring, and the locking ring are all coaxial. Optionally, the housing includes a tubular portion, and both the activation ring and the locking ring extend around the tubular portion of the housing.
[0009] Optionally, the connecting mechanism is a snap-fit engagement. Optionally, the connector on the locking ring is a hook on the flexible arm. Optionally, the connector on the activation ring is a protrusion or rib. Optionally, the flexible arm is flexible in the circumferential direction relative to the axis.
[0010] Optionally, the housing and the locking ring are rotated to lock relative to each other. Alternatively, the housing and the activating ring are rotated to lock relative to each other. Providing a rotary lock between the housing and the locking and activating rings helps ensure alignment of the connecting mechanism.
[0011] During use, the activation ring can move distally from a position spaced apart from the locking ring to a position adjacent to the locking ring, and the activation ring and locking ring can then move together relative to the housing from the distal position to the proximal position, thereby locking the power unit sub-assembly after use. Optionally, when the activation ring moves to the position adjacent to the locking ring, a connecting mechanism connects the activation ring to the locking ring.
[0012] Optionally, the power unit subassembly includes a plunger rod, and the housing includes a flexible arm, at least a portion of which is within the activation ring, and a portion of the flexible arm of the housing extends into a recess in the plunger rod. When the activation ring moves distally, it no longer restricts the flexible arm from bending away from the axis, allowing the flexible arm to move out of the recess in the plunger rod, thereby allowing the plunger rod to move axially and activating the drug delivery device, of which the power unit subassembly is a part.
[0013] Another aspect of the invention includes an autoinjector comprising a power unit subassembly of any of the preceding claims. Optionally, the autoinjector includes a needle guard abutting an activation ring.
[0014] Another aspect of the invention includes a power unit subassembly comprising a housing, a locking ring, and an activation ring, wherein the locking ring is connected to the activation ring when the activation ring moves in a distal direction, and wherein the activation ring and the locking ring move together in a proximal direction when the activation ring subsequently moves in a proximal direction.
[0015] Another aspect of the invention includes a power unit subassembly comprising a housing, a locking ring, and an activation ring, wherein in a first state, the activation ring is in a first proximal position relative to the housing, and the locking ring is in a distal position, wherein the activation ring is spaced apart from the locking ring in an axial direction; wherein in a subsequent second state, the activation ring is in the distal position, the locking ring is in the distal position, and the activation ring is adjacent to the locking ring; and wherein in a subsequent third state, the activation ring is in a second proximal position (optionally the same as the first proximal position), and the locking ring is in the proximal position, wherein the activation ring is adjacent to the locking ring.
[0016] Generally, unless otherwise expressly defined herein, all terms used in the claims shall be interpreted in accordance with their ordinary meaning in the art. Unless otherwise expressly stated, all references to “a / the element, device, component, part, apparatus, etc.” shall be interpreted in an open-ended manner as referring to at least one instance of the element, device, component, part, apparatus, etc. Attached Figure Description
[0017] Embodiments of this disclosure will now be described by way of example with reference to the accompanying drawings, in which:
[0018] Figure 1 A perspective view of the power unit subassembly with a needle guard is shown.
[0019] Figure 2 It shows Figure 1 The morphology of the components during drug delivery.
[0020] Figure 3 It shows Figure 1 The shape of the components after drug delivery.
[0021] Figure 4 It shows Figure 1 Two perspective views of the locking ring.
[0022] Figure 5 It shows Figure 1 Two perspective views of the activation ring.
[0023] Figure 6 It shows Figure 1 A perspective view of the casing.
[0024] Figure 7 It shows including Figure 1 A perspective view of the components of an auto-injector.
[0025] Figure 8 It shows Figure 1 A perspective view of the needle guard.
[0026] Figure 9 It shows Figure 7 A cross-sectional perspective view of a portion of an autoinjector.
[0027] Figure 10 It shows Figure 7 Another cross-sectional perspective view of a portion of an autoinjector.
[0028] Figure 11 A cross-sectional view showing an alternative approach to the interaction surfaces on the locking ring and the housing is shown.
[0029] Figure 12 and 13 It shows Figure 1 The interacting surfaces of the locking ring and housing of the power unit sub-assembly.
[0030] Figure 14 and 15 An alternative shape for the interacting surfaces on the locking ring and the housing is shown. Detailed Implementation
[0031] The power unit sub-assembly 10 will now be described. Power unit sub-assembly 10 (see, for example, [reference needed]). Figure 1 The power unit subassembly 10 extends axially from the proximal end 14 to the distal end 16 along axis 12. The power unit subassembly 10 includes a housing 20 (or rear housing), an activation ring 40, a locking ring 60, and an optional spring 80. The housing 20 extends from the distal end 16 of the power unit subassembly 10. The locking ring 60 is slidable relative to the housing in the axial direction. The activation ring 40 is slidable relative to the housing in the axial direction and is also slidable relative to the locking ring 60. The locking ring 60 is arranged closer to the distal end 16 of the power unit subassembly 10 than the activation ring 40.
[0032] The power unit subassembly 10 includes a connection mechanism. During use, this connection mechanism enables the locking ring to be connected to the activation ring. The connection mechanism includes a connector on the locking ring and a corresponding connector on the activation ring. In this example, the connector on the activation ring 40 is a protrusion 46, and the connector on the locking ring is a hook 64 on the flexible arm 62 (see, for example, [link to relevant documentation]). Figure 4 Alternatively, the connector on the locking ring can be a protrusion, while the connector on the activating ring can be a hook on a flexible arm. Other snap-fit designs or other types of connections, such as friction-fit connections, can also be used.
[0033] The power unit subassembly 10 also includes a locking mechanism. This locking mechanism locks the power unit subassembly 10 after use. The locking mechanism includes a distal-facing surface on a locking ring and a corresponding proximal-facing surface on the housing. In this example, the distal-facing surface on the locking ring is the distal-facing surface 72 of the protrusion 70, and the proximal-facing surface on the housing is the proximal-facing surface 24 on the flexible arm 22 of the housing 20 (see [link]). Figure 6 ).
[0034] Figures 11 to 15 Three examples are shown illustrating how the locking ring and the housing interact. Figure 12 and 13 The above examples (e.g., in) are shown Figure 6 and Figure 9 A close-up view of the configuration used in this configuration. In this configuration, in addition to the proximal surface 24 and the distal surface 72, there is a proximal protrusion 25 at the proximal end of the flexible arm 22. The proximal protrusion 25 extends further in the proximal direction than the proximal surface 24 of the flexible arm 22, thus providing radial support for the alignment of the proximal surface 24 and the distal surface 72. The proximal protrusion 25 is preferably further away from axis 12 than the distal surface 72 (see [reference]). Figure 1 ).
[0035] Figure 14 and 15 A distally extending protrusion 67 is shown positioned at the distal end of the locking ring 60. The distally extending protrusion 67 extends further in the distal direction than the distally facing surface 72, thus providing radial support for the alignment of the proximal facing surface 24 and the distally facing surface 72. The distally extending protrusion 25 is preferably closer to axis 12 than the proximal facing surface 24 (see [reference]). Figure 1 ).
[0036] Figure 11 An alternative is shown that does not provide an axially extending protrusion 25. In another alternative, it is provided with Figure 12 The protrusions 25 extending proximally and 67 extending distally.
[0037] Now refer to Figures 1 to 3 This section describes the operation of the power unit subassembly 10. Before use, the power unit subassembly 10 is typically in a state of... Figure 1 The configuration is shown. In this configuration, the locking ring 60 is in a first position (distal position) relative to the housing 20, and the activation ring 40 is in a first position (first proximal position) relative to the housing 20. The activation ring 40 is spaced apart from the locking ring 60.
[0038] During the use of the drug delivery device comprising the power unit subassembly as described herein, the activation ring 40 is first pushed distally relative to the housing 20. The activation ring 40 thus moves from a first position to a second position (distal position). Typically, the locking ring 60 does not move during this stage. In the example shown, the needle guard 120 pushes the activation ring 40 distally; of course, another activator (e.g., a button) can also be used to push the activation ring 40 distally. After the activation ring 40 is pushed distally, the locking ring 60 is connected to the activation ring 40 by a connecting mechanism. In this example, the injection will be performed when the power unit subassembly 10 is in the... Figure 2 Perform in the position shown (see also) Figure 9 —In this example, since the activation ring 40 no longer obstructs the movement of the second flexible arm 32 of the housing 20, the second flexible arm 32 of the housing 20 is now able to move away from the axis, which allows the plunger rod 108 to move in the proximal direction and to begin delivering the drug when positioned within the drug delivery device. At this stage, as... Figure 2 As shown, the activation ring 40 is adjacent to the locking ring 60, although there is still a gap between the locking ring 60 and the activation ring 40.
[0039] Once the injection is complete (or, in this example, if the user prematurely removes the drug delivery device from the injection site during the injection), the needle guard 120 moves proximally. In this example, the spring 80 then pushes the activation ring 40 from the second position to the third position (the second proximal position). In this case, the third position is the same as the first position; of course, the third position could also be a different position from the first position. Since the locking ring 60 is now attached to the activation ring 40 via the connecting mechanism, the locking ring 60 also moves with the activation ring 40 (from the first position of the locking ring 60 to the second position (the proximal position)). In this final position, the locking mechanism is activated—the distally facing surface on the locking ring (in this case, on the protrusion 70 of the locking ring 60) and the corresponding proximally facing surface on the housing (in this case, on the flexible arm 22) are opposite each other, thus preventing the locking ring 60 from moving back to its initial position (the first position), even though the needle guard 120 has been pushed distally.
[0040] Now refer to Figures 4 to 6 To explain the structure of the above components in more detail, Figures 4 to 6 The locking ring 60, the activation ring 40, and the housing 20 are shown respectively.
[0041] exist Figure 4The image shows two views of the locking ring 60. The locking ring includes an inner surface 61 and an outer surface 63. Various features can be seen in the ring structure, including a flexible arm 62 with a hook 64, a support surface 66, and protrusions 70 of the locking ring 60, each protrusion including a distally facing surface 72. Optional ribs 68 are also shown. In this example, the distally facing surface 72 differs from the distal end surface 65 of the locking ring 60; the distally facing surface 72 retracts from the distal end surface 65 in the axial direction, but the distally facing surface could also be part of the distal end surface.
[0042] exist Figure 5 The image shows two views of the activation ring 40. The activation ring includes an inner surface 55 facing the axis 12 and an outer surface 56 facing away from the axis 12. Several features can be seen in the ring structure, including a proximal surface 42, optional ribs 44 on the inner surface 55 of the activation ring 40, protrusions (or ribs) 46 on the outer surface 56 of the activation ring 40, a distal surface 48, and an inclined surface 50. The inclined surface 50 is at an angle relative to the axis, for example, between 15 and 75 degrees (preferably 30 to 60 degrees), and is optional, but makes it easier for the activation ring 40 to move past the flexible arm 22 of the housing 20 during use, thereby advantageously reducing friction during use.
[0043] exist Figure 6 The housing 20 is shown in more detail below. Numerous features are visible on the housing 20, including a tubular body 26 and flexible arms 22, each having a proximal surface 24. Several other optional features of the housing are also shown and will now be briefly described. These features include ribs 30 that can help connect the housing 20 to another part of the completed drug delivery device (e.g., housing 102); cutouts 31 in the ribs 30 that can help align components during assembly; a second flexible arm 32 that can hold the plunger rod 108 in place before device activation; a protrusion 33 on the second flexible arm 32 that can be configured to prevent device activation before the activation ring 40 moves distally; a longitudinal groove 34 that can interact with the ribs 44 of the activation ring 40 to limit rotation of the housing 20 relative to the activation ring 40; and a protrusion 35 in the longitudinal groove 34 that can prevent the activation ring 40 from disengaging from the proximal end of the housing 20. An optional support arm 36 for the housing is also shown. This support arm 36 may be flexible and may help support the distal end of the main body container 114 and / or help control tolerances within the drug delivery device.
[0044] The power unit sub-assembly described herein can be used in pharmaceutical delivery devices, such as autoinjectors. Figure 7 An example of an autoinjector 100 that can use the power unit sub-assemblies described herein is shown. Figure 7In the image, the housing 20 of the autoinjector 100 is visible at the distal end 16, and a cap 106 is present at the proximal end 14. A housing 102 (which may be a single piece or multiple pieces) extends between the cap and the housing. An optional window 104 in the housing 102 is also visible. Another example of an autoinjector that can use the power unit subassemblies described herein is shown in WO2011 / 123024, which is incorporated herein by reference.
[0045] An autoinjector including the power unit subassembly described herein typically comprises a needle guard, an optional cap, a housing, a body container containing the drug, a syringe holder supporting the body container, and a drug delivery component, such as a needle or jet injector. Furthermore, the power unit subassembly typically includes a piston rod and the aforementioned power unit subassembly. However, many different designs can work with the power unit subassembly described herein. For example, the syringe holder 116 may be part of the housing, the housing may be part of the casing, and / or the drug delivery component may be part of the body container; only a few simple variations are listed here.
[0046] For the sake of completeness, Figure 8 An example of a needle guard 120 that can be used with the power unit subassembly described herein is shown. The needle guard 120 includes two distally extending arms 122. Figures 1 to 3 As shown, the distal surface of the arm can interact with the activation ring 40. A notch visible at the proximal end of the needle sheath 120 is optional, but may be included to interact with the cap, for example as described in PCT / EP2020 / 086279, which is incorporated herein by reference.
[0047] As background, Figure 9 and Figure 10 A reference is shown inside the autoinjector. Figures 1 to 6 The aforementioned power unit sub-component. Figure 9 This shows when the power unit sub-assembly 10 is in Figure 2 The selected component is shown in the position shown (but the plunger spring is not shown). Figure 10 This shows when the power unit sub-assembly 10 is in Figure 3 The selected component is shown in the indicated position. In addition to the features shown above, especially... Figure 10 The plunger rod 108, plunger rod spring 110, and U-shaped bracket 112 can be seen in the middle.
[0048] In this example, the housing 20 (especially the tubular portion 26 of the housing) extends through the locking ring 60 and the activation ring 40 (see, for example, [link to example]). Figure 1Thus, the housing can support the locking ring and the activation ring, and keep them in place relative to the housing. This function can also be achieved by a power unit subassembly or another part of the agent delivery device. As mentioned above, many structural features of the housing 20 are not essential and will not be described in detail again.
[0049] The flexible arm 22 on housing 20 is optional, and the proximal surface on housing can be located at other positions on housing. The distal surface on the locking ring can optionally be located on the flexible arm of the locking ring. The flexible arm 22 is flexible in the radial direction, but can also be bent in other directions, such as in the circumferential direction.
[0050] The various features described in this article (e.g.) Figure 4 and Figure 5 The features of the locking ring 60 and the activation ring 40 shown are mostly arranged in pairs (and some features (such as the flexible arm 62 and the rib 68) are arranged in quadruplicate). Alternatively, other numbers of these features may be provided—generally, one of each feature described herein is sufficient, but having two or more equidistant features around the circumference is advantageous in terms of component balance (e.g., in terms of force transmission between components).
[0051] Locking ring 60 and activating ring 40 are shown to extend continuously around the axis, but one or both may extend only partially around the axis. When viewed perpendicular to the axis, the cross-sections of locking ring 60 and activating ring 40 both appear circular, but one or both may have another shape.
[0052] In the above example, the optional rotational locking between the housing and the activation ring is achieved by the rib 44 and the corresponding longitudinal groove 34. The rotational locking may also include a protrusion 35 that prevents the activation ring 40 from disengaging from the proximal end of the housing 20. The rotational locking can also be achieved in other ways, for example, by the inner surface 55 of the activation ring 40 being non-circular in a cross-section perpendicular to axis 12 and the corresponding outer surface of the housing being correspondingly non-circular.
[0053] In the above example, the second optional rotational locking between the housing and the locking ring is achieved by rib 68 and arm 22, wherein rib 68 extends circumferentially on either side of arm 22. The rotational locking can also be achieved in other ways, for example by the inner surface 55 of the locking ring 60 being non-circular in cross-section perpendicular to axis 12 and the corresponding outer surface of the housing being non-circular.
[0054] In the above example, the flexible arm 62 of the locking ring 60 is flexible in the circumferential direction, but it can also bend in other directions (e.g., the radial direction).
[0055] The support surface 66 is optional (the locking ring 60 does not necessarily have to abut against the activating ring 40 for the mechanism to operate; in some embodiments, a gap may still exist between the locking ring and the activating ring even after they are joined together), but it can limit how far the needle guard can be pushed back. Alternatively, a limit can be provided in other locations on the device, for example, by a protrusion on the housing to limit the distal movement of the needle guard.
[0056] The protrusion 70 is optional, and the distal-facing surface 72 on the locking ring can be provided on another portion of the locking ring. The protrusion can interact with the arm of the housing to help hold the locking ring in place before use.
[0057] Spring 80 is optional. An alternative with a spring is to attach the needle guard to the activation ring as described below, in which case pulling the needle guard forward after use will also pull the activation ring forward (e.g., the needle guard can be moved forward by the needle guard spring, or the user can manually pull the needle guard forward by pulling the needle back in a proximal direction). In this example, spring 80 extends between the housing and the activation ring. In this example, the spring is located inside the locking ring and outside the tubular portion of the housing.
[0058] The autoinjector 100 has been shown above as an example, but more generally, other designs of autoinjectors or drug delivery devices may also utilize the power unit sub-assemblies described herein. The activation mechanism described herein is optional (whereby once the activation locking ring 60 is removed (e.g.) Figure 9 The second flexible arm 32 of housing 20 can move radially away from the axis, but other activation mechanisms are also possible—for example, by a user-operable button that is restricted by the activation ring before it moves distally and can move radially toward the axis after the activation ring has moved distally, thereby activating the device, for example by unlocking the plunger rod or activating the pneumatic injection mechanism. The power unit subassembly also includes a power source, although this is not directly related to the concept of a lock described herein. In some instances, the power unit subassembly is gas-driven, rather than mechanically driven (spring-driven) as in the example shown. The drug delivery device can be a single-use product (disposable). The plunger rod configuration is optional; in some instances, the plug of the main container can be moved proximally by another component or by an increase in fluid pressure near the plug. The U-shaped support configuration is also optional. The U-shaped support can be released by the plunger rod spring 110 and pushed against housing 20, thereby providing one or more clicks, for example, ending the click. Figure 10As shown, a guide rod 113 extending within the plunger rod spring 110 can be provided, although this feature is optional. The guide rod can be part of a U-shaped bracket (such as...). Figure 10 (As shown), it can also be a separate component.
[0059] The example above is illustrated in context with respect to a needle shield. This design can also be used in conjunction with other drug delivery components (such as jet injectors), therefore the term 'needle shield' as used herein can be collectively referred to as a 'drug delivery component shield'. Optionally, the activation ring 40 is a component of the needle shield 120. Optionally, the activation ring 40 is attached to the needle shield 120, for example, by snap-fit or adhesive adhesion.
[0060] Various modifications are possible to the embodiments described, and those skilled in the art will be able to conceive of such modifications without departing from the invention as defined by the appended claims.
Claims
1. A power unit subassembly (10) for a pharmaceutical delivery device (100), the power unit subassembly (10) extending axially from a proximal end (14) to a distal end (16) along an axis (12), the power unit subassembly (10) comprising: The housing (20) extending from the distal end of the power unit subassembly (10), A locking ring (60) capable of sliding axially relative to the housing (20), An activation ring (40) capable of sliding axially relative to the housing (20) and relative to the locking ring (60), wherein the locking ring (60) is arranged closer to the distal end of the power unit subassembly (10) than the activation ring (40). A connection mechanism for connecting the activation ring (40) to the locking ring (60) during use, the connection mechanism including a connector on the activation ring (40) and a corresponding connector on the locking ring (60), and A locking mechanism for locking the power unit subassembly (10) after use, the locking mechanism comprising a distal surface (72) on a locking ring (60) and a corresponding proximal surface (24) on the housing (20).
2. The power unit subassembly (10) as claimed in claim 1, comprising a spring (80) disposed between the housing (20) and the activation ring (40).
3. The power unit subassembly (10) as claimed in claim 1 or 2, wherein the housing (20) includes a flexible arm (22) extending in a proximal direction, wherein a proximal-facing surface (24) on the housing is on the flexible arm (22).
4. The power unit subassembly (10) as claimed in claim 3, wherein the flexible arm (22) is flexible in the radial direction relative to the axis (12).
5. The power unit subassembly (10) as claimed in claim 1 or 2, wherein the housing (20), the activation ring (40), and the locking ring (60) are all coaxial.
6. The power unit subassembly (10) as claimed in claim 1 or 2, wherein the housing (20) includes a tubular portion (26), and wherein both the activation ring (40) and the locking ring (60) extend around the tubular portion (26) of the housing (20).
7. The power unit subassembly (10) as claimed in claim 1 or 2, wherein the connecting mechanism is a snap-fit component.
8. The power unit subassembly (10) as claimed in claim 1 or 2, wherein the locking ring (60) includes a flexible arm (62) with a hook (64), the connector on the locking ring (60) is the hook (64) on the flexible arm (62), and the connector on the activation ring is a protrusion (46).
9. The power unit subassembly (10) as claimed in claim 8, wherein the flexible arm (62) of the locking ring (60) is flexible in the circumferential direction relative to the axis (12).
10. The power unit subassembly (10) as claimed in claim 1 or 2, wherein the housing (20) and the locking ring (60) are rotationally locked relative to each other, and wherein the housing (20) and the activation ring (40) are rotationally locked relative to each other.
11. The power unit subassembly (10) as claimed in claim 1 or 2, wherein, During use, the activation ring (40) can move distally from a position spaced apart from the locking ring (60) to a position adjacent to the locking ring (60), and The activation ring (40) and the locking ring (60) can then be moved together with the housing (20) from a distal position to a proximal position to lock the power unit subassembly (10) after use.
12. The power unit subassembly (10) as claimed in claim 11, wherein, When the activation ring (40) moves to a position adjacent to the locking ring (60), the connecting mechanism connects the activation ring (40) to the locking ring (60).
13. The power unit subassembly (10) of claim 1 or 2, wherein the power unit subassembly (10) includes a plunger rod (108) and the housing (20) includes a flexible arm (22), wherein at least a portion of the flexible arm (22) of the housing (20) is inside the activation ring (40), and wherein a portion of the flexible arm (22) of the housing (20) extends into a recess within the plunger rod (108).
14. An autoinjector comprising a power unit subassembly (10) as described in any of the preceding claims.
15. The autoinjector of claim 14, wherein the autoinjector includes a needle guard (120) abutting the activation ring (40).