Gap generating device

Abstract

A plunger assembly (100) for use with an automated injection device, comprising a cylinder (102) and a firing assembly (103) including a plunger rod (104) and a drive portion (105), the firing assembly (103) being axially movable relative to the cylinder (102), wherein the firing assembly (103) is configured to connect to the cylinder (102) at a connection point along the length of the cylinder (102) to fix the axial position of the drive portion (105) relative to the cylinder (102), and wherein the length of the cylinder (102) is configured to extend in a rearward direction such that the connection point and the forward end (106) of the plunger rod (104) are rearwardly movable.

Description

[0001] This application is a divisional application of Chinese invention patent application No. 202080088671.1 (filed on June 20, 2022; invention title: gap generating device). Technical Field

[0002] The present invention relates to an automated injection device, and more particularly, to a plunger assembly for use with an automated injection device and a method for assembling a sub-assembly of an automated injection device. Background Technology

[0003] An autoinjection device is a device for receiving a syringe and driving the syringe plunger into the syringe tubing without requiring any force from the user, typically used for the delivery of medications. Typically, an autoinjection device includes a plunger driver, which usually includes a spring configured to provide force to drive the syringe plunger into the tubing. The plunger driver is usually activated by operating a release mechanism (such as a button) on the autoinjection device or by applying pressure to the injection site via the autoinjection device. A safe autoinjection device may be one that includes a shield, which can be deployed to cover the needle of the syringe received within the autoinjection device after use. The shield of the autoinjection device can be deployed under the force applied by a driver, which can be a plunger driver or a separate shield driver.

[0004] An automated injection device comprising a syringe pre-filled with a substance (such as a drug) can be provided to a user, making the device ready for use. Therefore, the automated injection device can be transported to the user along with the substance already contained in the syringe within the device. The filling space of the pre-filled syringe can vary depending on the dosage of the drug to be administered to the user. Summary of the Invention

[0005] According to a first aspect of the invention, a plunger assembly for use with an automated injection device is provided, the plunger assembly including a cylinder and a firing assembly, the firing assembly including a plunger rod and a drive portion, the firing assembly being axially movable relative to the cylinder, wherein the firing assembly is configured to connect to the cylinder at a connection point along the length of the cylinder to fix the axial position of the drive portion relative to the cylinder, and wherein the length of the cylinder is configured to extend in a rearward direction such that the connection point and the forward end of the plunger rod are rearwardly movable.

[0006] Optionally, the firing assembly is retractably housed within the cylinder.

[0007] Optionally, the plunger assembly further includes a firing assembly locking feature configured to engage with a barrel locking feature for connecting the firing assembly to the barrel.

[0008] Optionally, the firing assembly locking feature is configured to engage with the barrel locking feature during relative rotation between the firing assembly and the barrel.

[0009] Optionally, the cylinder includes a first portion and a second portion, the second portion being axially movable relative to the first portion for extending the length of the cylinder rearward.

[0010] Optionally, the first portion is in front of the second portion, and the firing assembly is configured to be connected to the second portion.

[0011] Optionally, one of the first and second portions of the cylinder includes an inclined surface configured to interact with a cylinder follower located on the other of the first and second portions of the cylinder, and the cylinder follower is configured to extend over the inclined surface, and extending the cylinder rearward includes rotating the second portion relative to the first portion to cause a corresponding feature to extend over the inclined surface.

[0012] Optionally, the first part further includes a rotary lock configured to fix the first part in a rotatable manner relative to the housing of the automatic injection device.

[0013] Optionally, the plunger assembly further includes an actuator axially connected to the cylinder such that an axial force applied to the actuator inserts the cylinder into the automatic injection device, wherein the axial connection is configured to be overcome when forward movement of the cylinder is prevented due to continued application of the axial force, and wherein the actuator further includes a cylinder connector configured to connect the firing assembly to the cylinder when the axial force continues to be applied.

[0014] Optionally, one of the actuator and the cylinder includes an inclined surface configured to interact with a locking follower on the other of the actuator or the cylinder to convert the axial force, which will continue to be applied, at least partially into a rotational force, and wherein the inclined surface and the locking follower are configured to provide the axial connection.

[0015] Optionally, the actuator includes a sleeve configured to receive the cylinder within the sleeve.

[0016] Optionally, the inclined surface or another inclined surface is configured to interact with the locking follower or another follower to rotate the second portion of the cylinder relative to the first portion of the cylinder.

[0017] According to another aspect of the present invention, an automated injection device subassembly is provided, the automated injection device subassembly including a plunger assembly according to any one of claims 1 to 13, and the automated injection device subassembly further including a housing configured to receive the plunger assembly.

[0018] Optionally, the automatic injection device subassembly includes a rotary engagement feature configured to engage the rotary lock.

[0019] Optionally, the automatic injection device subassembly includes an axial end stop configured to receive the plunger assembly and prevent further forward movement of the plunger assembly.

[0020] Optionally, the housing is configured to receive the syringe, and the housing is also configured to position the syringe such that at least a portion of the syringe forms the axial end stop.

[0021] According to another aspect of the invention, an auto-injection device subassembly is provided, the auto-injection device subassembly including a plunger assembly and a housing, the plunger assembly including: a cylinder insertable into the housing; and a firing assembly including a plunger rod and a drive portion, the firing assembly being axially movable relative to the cylinder, wherein the firing assembly is configured to connect to the cylinder at a connection point along the length of the cylinder to fix the axial position of the drive portion relative to the cylinder, wherein the cylinder is configured to connect to the housing at a point during insertion into the housing, and wherein at least a portion of the cylinder is configured to be rearwardly movable to cause rearward movement of the connection point and the forward end of the plunger rod.

[0022] According to another aspect of the invention, a method is provided for assembling an autoinjection device subassembly for use with an autoinjection device, the method comprising: inserting a plunger assembly at least partially into a syringe tube, the plunger assembly including a barrel and a firing assembly, the firing assembly including a plunger rod and a drive portion, and the firing assembly being axially movable relative to the barrel such that a forward end of the plunger rod encounters a plug located within the tube; connecting the firing assembly to the barrel at a connection point along the length of the barrel to fix the axial position of the drive portion relative to the barrel; and rearwardly moving at least a portion of the barrel such that the connection point and the forward end of the plunger rod are rearwardly moved.

[0023] Optionally, moving at least a portion of the cylinder backward includes extending the length of the cylinder in a backward direction.

[0024] Optionally, the firing assembly further includes a firing assembly locking feature, and connecting the firing assembly to the barrel includes engaging the firing assembly locking feature with a barrel locking feature on the barrel.

[0025] Optionally, engaging the firing assembly locking feature with the barrel locking feature includes rotating at least one of the firing assembly and the barrel relative to the other of the firing assembly and the barrel.

[0026] Optionally, the cylinder includes a first portion and a second portion, and extending the cylinder rearward includes: moving one of the first portion and the second portion axially relative to the other of the first portion and the second portion.

[0027] Optionally, one of the first and second portions of the cylinder includes an inclined surface configured to interact with a cylinder follower located on the other of the first and second portions of the cylinder, and the cylinder follower is configured to pass over the inclined surface; and extending the cylinder rearward includes rotating the second portion relative to the first portion to cause a corresponding feature to pass over the inclined surface.

[0028] Optionally, the method further includes fixing the first portion relative to the housing of the automated injection device in a rotatable manner.

[0029] Optionally, the plunger assembly further includes an actuator axially connected to the cylinder, and the method further includes: inserting the cylinder into the automatic injection device by applying an axial force to the actuator; preventing further forward movement of the cylinder; continuing to apply the axial force to the actuator while preventing further forward movement of the cylinder, such that the axial connection between the actuator and the cylinder is overcome, and the cylinder connector of the actuator connecting the firing assembly to the cylinder.

[0030] Optionally, the axial connection includes an inclined surface on the actuator or the barrel, the inclined surface being configured to interact with a locking follower on the other of the actuator or the barrel, and the continued application of the axial force to the actuator causing the axial force to be applied at least partially converted into a rotational force in order to connect the firing assembly to the barrel.

[0031] Optionally, the inclined surface or another inclined surface is configured to interact with the locking follower or another follower, and moving at least a portion of the cylinder rearward includes: causing the inclined surface to interact with the locking follower so as to rotate the second portion of the cylinder relative to the first portion of the cylinder.

[0032] According to another aspect of the invention, a plunger assembly for use with an automated injection device is provided, the plunger assembly including a cylinder and a firing assembly, the firing assembly including a plunger rod and a drive portion, the firing assembly being axially movable relative to the cylinder, wherein the firing assembly is configured to be connected to the cylinder at a connection point along the length of the cylinder to fix the axial position of the drive portion relative to the cylinder, thereby defining the axial length of the plunger assembly.

[0033] Optionally, the firing assembly is retractably housed within the cylinder.

[0034] Optionally, the plunger assembly further includes a firing assembly locking feature configured to engage with a barrel locking feature for connecting the firing assembly to the barrel.

[0035] Optionally, the firing assembly locking feature is configured to engage with the barrel locking feature during relative rotation between the firing assembly and the barrel.

[0036] Optionally, the plunger assembly further includes an actuator axially connected to the cylinder such that an axial force applied to the actuator inserts the cylinder into the automatic injection device, wherein the axial connection is configured to be overcome when forward movement of the cylinder is prevented due to continued application of the axial force, and wherein the actuator further includes a cylinder connector configured to connect the firing assembly to the cylinder when the axial force continues to be applied.

[0037] Optionally, one of the actuator and the cylinder includes an inclined surface configured to interact with a locking follower on the other of the actuator or the cylinder to convert the axial force, which will continue to be applied, at least partially into a rotational force, and wherein the inclined surface and the locking follower are configured to provide the axial connection.

[0038] Optionally, the actuator includes a sleeve configured to receive the cylinder within the sleeve.

[0039] According to another aspect of the invention, a method is provided for assembling an autoinjection device sub-assembly for use with an autoinjection device, the method comprising: inserting a plunger assembly at least partially into a syringe tube, the plunger assembly including a barrel and a firing assembly, the firing assembly including a plunger rod and a drive portion, and the firing assembly being axially movable relative to the barrel such that a forward end of the plunger rod encounters a plug located within the tube; and connecting the firing assembly to the barrel at a connection point along the length of the barrel to fix the axial position of the drive portion relative to the barrel, thereby defining the axial length of the plunger assembly.

[0040] Optionally, the firing assembly further includes a firing assembly locking feature, and connecting the firing assembly to the barrel includes engaging the firing assembly locking feature with a barrel locking feature on the barrel.

[0041] Optionally, engaging the firing assembly locking feature with the barrel locking feature includes rotating at least one of the firing assembly and the barrel relative to the other of the firing assembly and the barrel.

[0042] Optionally, the plunger assembly further includes an actuator axially connected to the cylinder, and the method further includes: inserting the cylinder into the automatic injection device by applying an axial force to the actuator; preventing further forward movement of the cylinder; continuing to apply the axial force to the actuator while preventing further forward movement of the cylinder, such that the axial connection between the actuator and the cylinder is overcome, and the cylinder connector of the actuator connecting the firing assembly to the cylinder.

[0043] Optionally, the axial connection includes an inclined surface on the actuator or the barrel, the inclined surface being configured to interact with a locking follower on the other of the actuator or the barrel, and the continued application of the axial force to the actuator causing the axial force to be applied at least partially converted into a rotational force in order to connect the firing assembly to the barrel.

[0044] According to another aspect of the invention, an automated injection device subassembly is provided, the automated injection device subassembly including a plunger assembly according to any one of claims 20 to 26, and the automated injection device subassembly further including a housing configured to receive the plunger assembly.

[0045] Optionally, the automatic injection device subassembly further includes an axial end stop configured to prevent further forward movement of the plunger assembly.

[0046] Optionally, the housing is configured to receive the syringe, and the housing is also configured to position the syringe such that at least a portion of the syringe forms the axial end stop.

[0047] Optionally, the housing is configured to receive a syringe including a tube and a stopper located within the tube, wherein the connection point is positioned such that the forward end of the plunger rod contacts the stopper.

[0048] According to another aspect of the present invention, an automated injection device is provided, the automated injection device comprising a plunger assembly according to any one of claims 1 to 12 and 20 to 26, and / or an automated injection device subassembly according to any one of claims 13 to 16 and 29 to 30. Attached Figure Description

[0049] Figure 1a An isometric view of a portion of an exemplary plunger assembly is shown;

[0050] Figure 1b A side view of a portion of the first and second portions of the cylinder of an exemplary plunger assembly is shown;

[0051] Figure 2 An isometric view of an exemplary plunger assembly is shown;

[0052] Figure 3a and Figure 3b A partial cross-sectional view through an exemplary automated injection device sub-assembly is shown; and

[0053] Figures 4a to 4c Partial side views of an exemplary plunger assembly at different stages of operation are shown. Detailed Implementation

[0054] Typically, users are provided with an autoinjector ready for use, such that the forward end of the plunger rod remains in contact with the stopper, which in turn remains in contact with a substance such as a drug contained within the tubing. The plunger rod and stopper can be held in position such that backward movement away from the drug is impossible in the assembled (or ready-to-use / pre-use) configuration.

[0055] The inventors have realized that such a configuration does not allow the substance contained within the syringe tubing to diffuse forward toward the stopper. In a particular case, transporting such a pre-filled syringe in low-pressure environments (such as high-altitude areas) may cause drug leakage because if the plunger and stopper are fixed in place, there is no space for the drug to diffuse into it except from the forward end of the syringe.

[0056] This document generally discloses an exemplary plunger assembly for use with an automated injection device. The exemplary plunger assembly may include a barrel and a firing assembly, the firing assembly including a plunger rod and a drive portion. In a particular arrangement, prior to assembly of the automated injection device, the firing assembly is axially movable relative to the barrel until its relative position to the barrel is set during assembly. After the relative position is set, it is conceivable to connect the firing assembly to the barrel, as forward movement of the barrel causes forward movement of the plunger rod. In an exemplary arrangement, the connection of the firing assembly to the barrel fixes the axial position of the drive portion relative to the barrel. In some exemplary arrangements, the syringe may be held within the housing of the automated injection device. During assembly of the automated injection device, the plunger assembly may be inserted into the housing, and the plunger rod is then inserted into the tubing of the syringe. The forward end of the plunger rod may contact a stopper, and because the firing assembly is axially movable relative to the barrel, the forward movement of the plunger rod is held by the stopper, while the barrel continues to move forward until it is properly positioned or secured within the housing. At this point, the firing assembly and / or the cylinder are configured to be connected together at least axially at the connection point, and the plunger rod has a length that contacts the plug. The cylinder is configured such that the connection point can be moved rearward. The rearward movement of the connection point causes the plunger rod to move rearward, thereby moving the forward end of the plunger rod away from the plug, thus creating a gap between the forward end of the plunger rod and the plug. In an exemplary arrangement of the plunger assembly, the length of the cylinder can be increased. The length of the cylinder can be increased rearward to allow the connection point to move rearward.

[0057] When the exemplary plunger assembly is used with an autoinjection device, a gap is defined between the stopper and the forward end of the plunger rod when the autoinjection device is in its assembled state. The gap between the stopper and the forward end of the plunger rod accommodates the diffusion of medication in the tubing of a pre-filled syringe, thereby preventing leakage.

[0058] Throughout this specification, the term "forward" refers to the end of the autoinjection device from which the drug is delivered. In other words, the forward end of the autoinjection device is the end that is close to the injection site during use. The term "rear" or "backward" refers to the plunger end of the autoinjection device or its components. In other words, the term "backward" refers to the end that is away from or away from the injection site during use. Other relative terms such as "axial," "longitudinal," etc., are used to aid in the description of the device and are not intended to be considered as limiting the scope of the claimed invention.

[0059] The term "tube" can encompass any sleeve, collar, or other component capable of receiving a firing assembly. For example, a sleeve, collar, or other component configured to receive a firing assembly in a retractable manner so that the firing assembly can move within it.

[0060] Figure 1a An exemplary plunger assembly 100 is shown. The plunger assembly 100 includes a cylinder 102 and a firing assembly 103, the firing assembly 103 including a plunger rod 104 and a drive portion 105. The firing assembly 103 is axially movable relative to the cylinder 102. Thus, the plunger rod 104 is also axially movable relative to the cylinder 102.

[0061] The plunger rod 104 can be connected to the drive section 105 such that axial movement of the plunger rod 104 causes axial movement of the drive section 105, and vice versa. Thus, the relative movement of the firing assembly 103 relative to the cylinder 102 also encompasses the relative movement of the plunger rod 104 relative to the cylinder 102.

[0062] In an exemplary arrangement, the firing assembly 103 may further include a delivery driver disposed between the drive portion 105 and the plunger rod 104. This delivery driver can bias the plunger rod 104 forward relative to the drive portion 105. When the plunger rod 104 is disconnected from the drive portion 105, it can move relative to the drive portion 105 in a delivery stroke under the bias of the delivery driver.

[0063] In the example shown, the firing assembly 103 is received within the cylinder 102. The forward end 106 of the plunger rod 104 extends from the forward end 108 of the cylinder 102. The plunger rod 104 is received in a telescoping manner within the cylinder 102 such that the extent to which the forward end 106 of the plunger rod 104 extends from the forward end 108 of the cylinder 102 can be varied.

[0064] Those skilled in the art will understand that alternative arrangements that allow relative axial movement between the firing assembly 103 and the barrel 102 can be utilized. For example, in an alternative arrangement, the barrel 102 and the firing assembly 103 can be configured to slide side-by-side with each other. Other configurations will be conceived by those skilled in the art.

[0065] The firing assembly 103 may include a firing assembly locking feature 110 (in Figure 1b(Best shown in the diagram). The firing assembly locking feature 110 can be configured to engage with the barrel locking feature 112 to connect the plunger rod 104 to the barrel 102. The firing assembly locking feature 110 can be configured to engage with the barrel locking feature 112 at a connection point. In the exemplary plunger assembly 100, the firing assembly 103 can be connected to the barrel 102 at multiple locations along the length of the barrel 102. Thus, the term "connection point" encompasses one of the multiple locations along the length of the barrel 102 where the firing assembly 103 is connected to the barrel 102. When the firing assembly 103 and the barrel 102 are connected, for example when the firing assembly locking feature 110 engages with the barrel locking feature 112, the axial position of the drive portion 105 and / or the plunger rod 104 relative to the barrel 102 can be fixed.

[0066] In the exemplary plunger assembly 100, the drive portion 105 includes a firing assembly locking feature. In such an arrangement, engagement of the firing assembly locking feature 110 with the barrel locking feature 112 can fix the axial position of the drive portion 105 relative to the barrel 102. As described above, in an arrangement where the plunger rod 104 is connected to the drive portion 105, fixing the axial position of the drive portion 105 relative to the barrel 102 fixes the axial position of the plunger rod 104 relative to the barrel 102.

[0067] exist Figure 1a and Figure 1b In the exemplary plunger assembly 100, the firing assembly locking feature 110 and the cylinder locking feature 112 include teeth. The teeth of the firing assembly locking feature 110 and the cylinder locking feature 112 can be configured to mesh together to connect the firing assembly 103 and the cylinder 106. Figure 1a and Figure 1b In the exemplary arrangement shown, the teeth of the firing assembly 103 and the teeth of the barrel 102 can be tilted rearward. This ensures that the teeth can engage regardless of the axial position of the firing assembly 103 relative to the barrel 102 before engagement. That is, if the teeth of the firing assembly locking feature 110 and the teeth of the barrel locking feature 112 are not aligned before engagement, the rearward-tilted teeth are used to guide the corresponding teeth to align.

[0068] Those skilled in the art will understand that alternative firing assembly locking features 110 and 112 can be utilized. For example, protrusion and recess arrangements, clips, magnetic devices, and / or ratchet mechanisms. Those skilled in the art will be able to conceive of other configurations. Those skilled in the art will also understand that, although... Figure 1a and Figure 1bThe exemplary locking features 110 and 112 shown provide a plurality of discrete positions along the length of the barrel 102, to which the firing assembly 103 can be connected. However, a continuous connection arrangement can be provided so that the firing assembly 103 can be connected to the barrel 102 at substantially any point along the length of the barrel 102.

[0069] exist Figure 1a and Figure 1b In an exemplary arrangement, the barrel 102 and the firing assembly 103 each include linear traces of teeth extending along at least a portion of the length of the barrel 102 and at least a portion of the length of the firing assembly 103, respectively. Figure 1a and Figure 1b In this arrangement, the linear traces of the teeth extend along at least a portion of the length of the drive portion 105 of the firing assembly 103. Those skilled in the art will understand that other tooth arrangements are also feasible, as long as the teeth of the firing assembly 103 can engage with the teeth of the cylinder 102 at multiple points along the length of the cylinder 102. The pitch of the teeth in the linear traces of the cylinder 102 and the pitch of the teeth in the linear traces of the firing assembly 103 can be equal. In the exemplary plunger assembly 100, the length of the linear traces of the teeth of the cylinder 102 can be greater than the length of the linear traces of the teeth of the firing assembly 103.

[0070] Those skilled in the art will understand that the number of teeth and the tooth pitch can vary based on the expected number of potential connection points along the length of the cylinder 102. Thus, changing the number of teeth and / or the tooth pitch will allow for variations in the number of potential connection points.

[0071] The firing assembly 103 may include a protrusion 114. Figure 1a and Figure 1b In the exemplary arrangement shown, the drive portion 105 includes a protrusion 114. The protrusion 114 may be configured to interact with the barrel 102 to prevent relative rotation between the firing assembly 103 and the barrel 102 in a first direction. Figure 1a and Figure 1b In an exemplary arrangement, the protrusion 114 is received within the trace 116 of the barrel 102. The edge of the trace 116 may include a stop surface 118. When the protrusion 114 abuts against the stop surface 118 of the barrel 102, relative rotation between the firing assembly 103 and the barrel 102 in a first direction can be prevented.

[0072] The trace 116 of the barrel 102 can be an axial (or vertical) trace arranged substantially parallel to the longitudinal axis of the barrel 102. The trace 116 of the barrel 102 can serve as a guide for the axial movement of the firing assembly 103 relative to the barrel 102. Figure 1a and Figure 1bIn an exemplary arrangement, the protrusion 114 may be configured to ride along the stop surface 118 of the track 116 as the firing assembly 103 moves axially within the barrel 102.

[0073] exist Figure 1a and Figure 1b In the exemplary firing assembly 103 shown, the firing assembly locking feature 110 can be arranged such that relative rotation between the firing assembly and the barrel 102 engages the firing assembly locking feature 110 and the barrel locking feature 112. The relative rotation for engaging the firing assembly locking feature 110 and the barrel locking feature 112 can be along a second direction opposite to the first direction.

[0074] The firing assembly 103 may also include a connecting surface 120. Figure 1a and Figure 1b In the exemplary arrangement, the protrusion 114 includes a connecting surface 120; however, in an alternative arrangement, the connecting surface 120 may be detached from the protrusion 114. The connecting surface 120 may be configured to interact with the barrel 102 to allow the firing assembly 103 to be rotatably connected to the barrel 102. Figure 1a and Figure 1b In the example shown, the drive portion 105 includes a connection surface 120.

[0075] exist Figure 1a and Figure 1b In the exemplary arrangement, the linear traces of the teeth forming at least a portion of the firing assembly locking feature 110 can extend from the protrusion 114. The teeth of the firing assembly 103 can extend from the connecting surface 120 of the protrusion 114, which is opposite to the surface of the protrusion 114 configured to interact with the stop surface 118 of the trace 116. Thus, relative rotation between the firing assembly 103 and the barrel 102 in a second direction can cause the corresponding teeth of the barrel 102 and the firing assembly 103 to engage.

[0076] Generally, at least a portion of the barrel 102 is movable rearward so that the connection point is moved rearward after the firing assembly 103 is connected to the barrel 102. In the exemplary barrel 102, the length of the barrel may be extended rearward or increased.

[0077] Figure 1a and Figure 1b An exemplary cylinder 102 includes a first portion 122 and a second portion 124. At least one portion of the first portion 122 and the second portion 124 is axially movable relative to the other portion of the first portion 122 and the second portion 124. This relative axial movement between the first portion 122 and the second portion 124 can cause the cylinder 102 to extend rearward. Figure 1a and Figure 1bIn an exemplary arrangement, the relative rotation between the first portion 122 and the second portion 124 can cause relative axial movement between the first portion 122 and the second portion 124.

[0078] At least one of the first portion 122 and the second portion 124 may include an inclined surface 126 configured to interact with a cylindrical follower 128 on another portion of the first portion 122 and the second portion 124. Figure 1a and Figure 1b In an exemplary arrangement, the first portion 122 is in front of the second portion 124, and the first portion 122 includes an inclined surface 126. The second portion 124 includes a cylinder follower 128. In an alternative arrangement, those skilled in the art will understand that the first portion 122 may include the cylinder follower 128, and the second portion 124 may include the inclined surface 126. The cylinder follower 128 may be configured to ride over the inclined surface 126 when rotating relative to the first portion 122 and the second portion 124. Those skilled in the art will understand that the phrase "ride over" encompasses the travel of the corresponding feature along the inclined surface and is not intended to impose a positional limitation. That is, the cylinder follower 128 does not need to be located "above" the inclined surface. Figure 1a and Figure 1b In the illustrated arrangement, the driven portion 128 includes a protrusion. In an alternative arrangement, the driven portion 128 may include a stud or protrusion, a corresponding inclined surface, or any other feature capable of traveling on the inclined surface 126 when rotated relative to the first portion 122 and the second portion 124. In an alternative arrangement, the inclined surface 126 and the driven portion 128 may include corresponding threads.

[0079] The inclined surface 126 is tilted rearward. Therefore, as the cylinder follower 128 travels on the inclined surface 126, the second portion 124 moves axially rearward relative to the first portion 122. Thus, the inclined surface 126 converts rotational force into axial force when the first portion 122 and the second portion 124 rotate relative to each other. Those skilled in the art will understand that, in alternative arrangements, other methods can be used to induce relative axial movement between the first portion 122 and the second portion 124. For example, a biasing member can be configured to be released upon release from an initial state to bias the first and second portions away from each other. Other arrangements will be conceived by those skilled in the art. Furthermore, those skilled in the art will understand that after the cylinder 102 is connected to the plunger rod 104, the cylinder 102 itself can move rearward.

[0080] Cylinder 102 may include a rotary lock. This rotary lock may be configured to rotatably secure at least one of the first portion 122 and the second portion 124 relative to the housing of an automatic injection device into which the exemplary plunger assembly 100 can be inserted. Figure 1a and Figure 1b In the illustrated arrangement, the rotary lock is configured to rotatably secure the first (or forward) portion 122 relative to the housing (described in more detail below). The rotary lock may include arms 130a, 130b. Arms 130a, 130b extend radially outward from the first portion 122. Arms 130a, 130b may be configured to interact with corresponding features on the housing of the auto-injection device to prevent relative rotation between the housing and the first portion 122. For example, arms 130a, 130b may be configured to interact with protrusions (such as traces) located on or connected to the housing. Those skilled in the art will understand that alternative rotary locks may be used, for example, the housing may include a keyhole in which the first portion 122 is received. Those skilled in the art will be able to envision alternative possible arrangements. In another alternative arrangement, the rotary lock may be configured to rotatably secure the second (reverse) portion 124 relative to the housing, instead of rotatably securing the first portion 122 relative to the housing.

[0081] In the exemplary plunger assembly 100, the second (or rearward) portion 124 may include a cylinder locking feature 112, a trace 116, and a stop surface 118. Thus, in the exemplary plunger assembly 100, the firing assembly 103 may be configured to be connected to the second portion 124, and the connection point is therefore on the second portion 124.

[0082] Trajectory 116 extends substantially along the entire length of the second portion 124. As described above, in Figure 1a and Figure 1b In the exemplary arrangement shown, the cylinder locking feature 112 includes teeth. The teeth may be located on the radially inner surface of the second portion 124. Figure 1a and Figure 1b In the exemplary arrangement, the teeth are arranged close to the edge of the trace 116. The teeth may be arranged on the edge of the trace 116 opposite to the edge of the trace 116 including the stop surface 118. The linear trace of the teeth of the cylinder locking feature 112 may extend substantially over the entire length of the second portion 124.

[0083] In an alternative arrangement, the housing of the auto-injection device into which the plunger assembly 100 is inserted may include one or more features of the first portion 122. For example, the first portion 122 may be integral with the housing of the auto-injection device and configured to interact with the second portion 124 when the cartridge 102 is inserted into the housing. In other arrangements, the housing may include alternative features configured to interact with the cartridge 102 to reposition the connection point rearward after the firing assembly 103 is engaged with the cartridge 102. For example, one of the housing and the cartridge 102 may include a surface configured to interact at a point with a corresponding feature on the other of the housing and the cartridge 102 to cause the cartridge 102 to reposition rearward within the housing during insertion of the plunger assembly 102. This surface may be an inclined surface (e.g., as described above), and the interaction may cause relative rotation between the cartridge 102 and the housing (and the firing assembly 103), thereby repositioning the connection point rearward. In such an arrangement, the cartridge 102 may include a portion of the first portion 122 and the second portion 124.

[0084] The plunger assembly 100 may also include an actuator 136 (such as...) Figure 2 (As shown). When an axial force is applied to the actuator 136, the actuator 136 is able to move axially relative to the cylinder 102.

[0085] Actuator 136 can be configured to cause relative rotation between the first portion 122 and the second portion 124 when an axial force is applied to actuator 136. The axial force can be a forward force. For example, this axial force can be applied during the insertion of plunger assembly 100 into the housing of the automatic injection device.

[0086] As discussed above, relative rotation between the first portion 122 and the second portion 124 can cause the firing barrel locking feature 110 to engage with the barrel locking feature 112. In an exemplary arrangement, relative rotation between the first portion 122 and the second portion 124 can additionally or alternatively cause relative axial movement between the first portion 122 and the second portion 124.

[0087] exist Figure 2 In an exemplary arrangement, actuator 136 includes a barrel connector configured to cause barrel 102 to engage with firing assembly 103 when an axial force is applied to actuator 136. The barrel connector may include a beveled surface 142 configured to engage with a locking follower located on a second portion 124 of barrel 102. Figure 2 (Invisible to the naked eye) interaction. Those skilled in the art will understand that, in alternative arrangements, the second portion 124 of the cylinder 102 may include an inclined surface, and the actuator may include a locking follower. Figure 2In the exemplary arrangement, the locking follower includes a corresponding inclined surface; however, those skilled in the art will understand that in alternative arrangements, the locking follower may include a protrusion, a projection, or a stud, or any other component capable of traveling on the inclined surface. The inclined surface 142 may extend rearward. The locking follower may be configured to be located at the foremost position of the inclined surface 142 in the initial configuration of the plunger assembly 100.

[0088] exist Figure 2 In an exemplary arrangement, actuator 136 includes sleeve 144. The actuator may also include end cap 146. End cap 146 may be configured to abut against the rear face of the housing of the autoinjection device when the plunger assembly 100 is fully inserted into the housing of the autoinjection device.

[0089] exist Figure 2 In an exemplary arrangement, sleeve 144 extends from end cap 146. Sleeve 144 may be configured as receiving sleeve 102. In exemplary actuator 136, sleeve 144 is configured as a second portion 124 of receiving sleeve 102. In such an arrangement, sleeve 144 may include a beveled surface 142 (or, in an arrangement where the second portion 124 includes a beveled surface 142, sleeve 144 may include a locking follower).

[0090] Figure 3a and Figure 3b An automated injection device subassembly 300 is shown. The automated injection device subassembly 300 includes... Figure 1a , Figure 1b and Figure 2 The plunger assembly 100 and the housing 350. The plunger assembly 100 may be configured to be inserted into the housing 350.

[0091] The housing 350 may include a rotation engagement feature 352. The rotation engagement feature 352 may be configured as a rotation lock engaging the cylinder 102. The rotation engagement feature 352 of the housing 350 may be configured as a rotation lock engaging a first portion 122 of the cylinder 102 to prevent rotation of the first portion 122 relative to the housing 350.

[0092] exist Figure 2 , Figure 3a and Figure 3b In the exemplary arrangement, the rotational engagement feature 352 includes an inwardly extending protrusion. Those skilled in the art will understand that alternative rotational engagement features 352 can be used to prevent rotation of the first portion 122 relative to the housing 350. For example, in an alternative arrangement, the housing may include a keyhole configured to receive the first portion, or a high-friction material disposed on an inner surface of the housing may be configured to engage the face of the first portion to resist rotation of the first portion. Other arrangements will be conceived by those skilled in the art.

[0093] The protrusion may extend along at least a portion of the length of the housing 350 to form a trace. In such an arrangement, the rotary lock of the first portion 122 of the cylinder 102 may engage the rotary engagement feature 352 when the plunger assembly 100 is inserted into the housing 350. In an alternative arrangement, the rotary engagement feature 352 may include discrete protrusions positioned to engage the rotary lock of the cylinder 102 when the plunger assembly 100 is fully received within the housing 350.

[0094] exist Figure 3a and Figure 3b In an exemplary arrangement, the protrusion may be configured to interact with one of the arms 130a, 130b of the first portion 122 of the cylinder 102. Figure 3a and Figure 3b In an exemplary arrangement, the rotational engagement feature 352 includes two inwardly extending protrusions. These two inwardly extending protrusions may be opposite and are configured to engage corresponding arms 130a, 130b of the first portion 122. Engagement between the first protrusion and the first arm 130a prevents rotation of the first portion 122 relative to the housing 350 in a first direction, and engagement between the second protrusion and the second arm 130b prevents rotation of the first portion 122 in a second direction opposite to the first direction.

[0095] The automatic injection device subassembly 300 may include an axial end stop 358. The axial end stop 358 may be configured to prevent forward movement of the plunger assembly 100 when it is engaged with the axial end stop 358. The plunger assembly 100 may be configured to engage the axial end stop 358 during insertion of the plunger assembly 100 into the housing 350.

[0096] The housing 350 can be configured to receive the syringe 360. Figure 3a and Figure 3b In the exemplary arrangement shown, a portion of the syringe 360 ​​forms an axial end stop 358. Those skilled in the art will understand that alternative axial end stops 358 may be utilized in alternative arrangements. For example, the axial end stop 358 may include an inwardly extending protrusion or lip located on the housing and configured to engage a corresponding feature on the plunger assembly 100 to prevent forward movement within the housing 350.

[0097] The forward end of the cylinder 102 can be configured to abut against the syringe 360 ​​during insertion of the plunger assembly 100 into the housing 350. Figure 3a and Figure 3bIn an exemplary arrangement, the first portion 122 may be configured to abut against the syringe 360. In an alternative arrangement, the first portion 122 may be configured to abut against a component disposed between the syringe 360 ​​and the first portion 122. When the first portion 122 abuts against the syringe 360, further forward movement of the plunger assembly 100 is prevented.

[0098] The following is for reference. Figure 2 , Figure 3a and Figure 3b as well as Figures 4a to 4c To describe the operation of the plunger assembly 100.

[0099] Figure 2 The plunger assembly 100 is shown in its initial position. In the initial position, the firing assembly 103 is disconnected from the cylinder 102, and the firing assembly 103 is axially movable relative to the cylinder 102. In an exemplary arrangement, in the initial position, the actuator 136 and the cylinder 102 may be axially connected such that axial movement of one of the actuator 136 and the cylinder 102 causes axial movement of the other. An axial force can be applied to the actuator 136 to insert the cylinder 102 into the automatic injection device. Figure 3a and Figure 3b In the example shown, an axial force is applied to the actuator 136 to insert the cylinder 102 into the housing 350.

[0100] The plunger assembly 100 can be inserted into the barrel of the syringe 360. Figure 3a and Figure 3b In the exemplary arrangement shown, inserting the plunger assembly 100 into the tube of the syringe 360 ​​includes inserting the plunger assembly 100 into the housing 350.

[0101] Inserting the plunger assembly 100 into the housing 350 allows the rotary lock of the cylinder 102 to engage with the rotary engagement feature 352 of the housing 350. Figure 3a and Figure 3b In the exemplary arrangement shown, the plunger assembly 100 is inserted into the housing 350 such that the arms 130a, 130b of the first portion 122 of the cylinder 102 engage with corresponding protrusions on the housing 350. The engagement of the arms 130a, 130b with the corresponding protrusions prevents rotation of the first portion 122 relative to the housing 350.

[0102] The plunger assembly 100 can be moved forward within the housing 350. In an exemplary arrangement, the plunger assembly 100 can be moved forward by applying an axial force to the actuator 136. Since the actuator 136 is axially connected to the cylinder 102, applying an axial force to the actuator 136 causes the cylinder 102 and the firing assembly 103 to move forward within the housing 350.

[0103] During the forward movement of the plunger assembly 100, at a point the forward end 106 of the plunger rod 104 may contact a stopper located within the tube of the syringe 360. Those skilled in the art will understand that the syringe 360 ​​may be a pre-filled syringe, and the point at which the plunger rod 104 contacts the stopper will depend on the filling space of the pre-filled syringe.

[0104] Once the plunger rod 104 contacts the plug, it prevents the firing assembly 103 from moving further forward. Thus, the further forward force applied to the plunger assembly 100 causes relative axial movement between the plunger rod 104 and the cylinder 102.

[0105] exist Figure 3a and Figure 3b In this exemplary arrangement, since the actuator 136 and the cylinder are connected, further forward movement of the actuator under axial force causes further forward movement of the cylinder 102. Thus, the cylinder 102 continues to move forward within the housing 350, while the firing assembly 103 remains in substantially the same axial position relative to the housing 350. In this way, a greater length of the plunger rod 104 is accommodated within the cylinder 102, and the extent to which the forward end 106 of the plunger rod 104 extends beyond the forward end 108 of the cylinder 102 begins to decrease.

[0106] The cylinder 102 can move further forward until the plunger assembly 100 engages the axial end stop 358. When the plunger assembly 100 engages the axial end stop 358, further forward movement of the cylinder 102 is prevented. Figure 3a and Figure 3b In the exemplary arrangement shown, the syringe 360 ​​forms an axial end stop 358, and the plunger assembly 100 is further moved forward until the barrel 102 engages with the syringe 360. In the exemplary arrangement, the plunger assembly 100 can be moved forward within the housing 350 until the barrel 102 abuts against the syringe 360, for example until the first portion 122 of the barrel 102 abuts against the syringe 360.

[0107] When forward movement of the cylinder 102 is prevented, continuing to apply an axial force to the actuator 136 can overcome the axial connection between the cylinder 102 and the actuator 136. After overcoming this axial connection, further applying an axial force to the actuator 136 can cause the cylinder connector of the actuator 136 to connect the firing assembly 103 to the cylinder 102. The axial connection, or features leading to it, may include the inclined surface 142 of the actuator 136 and a locking follower on the cylinder 102. In such an arrangement, when the cylinder moves freely forward, applying an axial force to the actuator 136 can cause a corresponding axial movement of the cylinder. In such an arrangement, when the cylinder 102 moves freely forward, the locking follower may not travel along the inclined surface 142. However, when forward movement of the cylinder 102 is prevented, continuing to apply an axial force to the actuator can cause the locking follower to travel along the inclined surface 142, thereby converting the continued application of axial force at least partially into rotational force. That is, when the stop cylinder moves forward, the axial connection can be overcome while axial force continues to be applied to the actuator.

[0108] Those skilled in the art will understand that the connection point between the firing assembly 103 and the barrel 102 can depend on the position of the stopper within the syringe tubing. That is, the lower the fill space of the syringe, the further forward the stopper will be within the syringe tubing, and therefore the further forward the connection point will be.

[0109] exist Figure 3a and Figure 3b In the exemplary arrangement, relative rotation between the barrel 102 and the firing assembly 103 causes the firing assembly 103 and the barrel 102 to connect. When the firing assembly 103 is connected to the barrel 102, the axial position of the firing assembly 103 relative to the barrel 102 is fixed. Figure 3a and Figure 3b In the example shown, the axial position of the drive portion 105 relative to the cylinder 102 is fixed. The axial position of the firing assembly 103 (or specifically, the drive portion 105) relative to the cylinder 102 can be fixed such that the forward end 106 of the plunger rod 104 contacts the plug.

[0110] exist Figure 3a and Figure 3bIn the exemplary arrangement, the interaction between the inclined surface 142 of the actuator and the locking follower on the second portion 124 of the barrel 102 causes relative rotation between the barrel 102 and the firing assembly 103, thereby connecting the firing assembly 103 and the barrel 102 together. Since the barrel 102 cannot move further forward, a further axial force applied to the actuator 136 overcomes the axial connection between the actuator 136 and the barrel 102. Overcoming this axial connection causes the locking follower on the second portion 124 of the barrel 102 to pass over the inclined surface 142 of the actuator 136. This causes the barrel 102 to disconnect from the actuator 136 and causes the second portion 124 to rotate relative to the actuator 136. This, in turn, causes relative rotation between the second portion 124 and the firing assembly 103. Thus, the barrel locking feature 112 engages with the firing assembly locking feature 110. Figure 3a and Figure 3b In the arrangement shown, engaging the barrel locking feature 112 with the firing assembly locking feature 110 includes causing the corresponding teeth to engage.

[0111] Since the rotation lock of the first part 122 of the cylinder 102 engages with the rotation engagement feature 352, the second part 124 also rotates relative to the first part 122.

[0112] In an alternative arrangement, rotation of the housing 350 relative to the barrel 102 can induce relative rotation between the barrel 102 and the firing assembly 103. In such an arrangement, the barrel 102 may include a connecting feature configured to attach the barrel 102 to the housing 350 when inserted into the housing 350. In this arrangement, rotation of the housing 350 can induce engagement of the connecting feature on the barrel with a corresponding connecting feature on the housing 350, such that rotation of the housing 350 induces rotation of the barrel 102 relative to the firing assembly 103. Relative rotation between the firing assembly 103 and the barrel 102 can engage the firing assembly locking feature 110 with the barrel locking feature 112. Those skilled in the art will understand that such an arrangement may not include the actuator 136. In this way, the barrel 102 and the firing assembly 103 can be inserted axially into the housing 350, and the housing can be rotated to connect the firing assembly 103 to the barrel 102 and / or to move the connection point rearward.

[0113] Figures 4a to 4c The relative positions of the first part 122 and the second part 124 at various points are shown during the rotation of the second part 124.

[0114] Figure 4a The relative positions of the first part 122 and the second part 124 are shown before the cylinder 102 is connected to the firing assembly 103 (and therefore before the second part 124 begins to rotate relative to the firing assembly 103 and the first part 122).

[0115] The second part 124 rotates relative to the firing assembly 103 to connect the barrel 102 and the firing assembly 103, causing the barrel follower 128 of the second part 124 to rotate toward the inclined surface 126 of the first part 122. Figure 4b The relative positions of the first portion 122 and the second portion 124 are shown at the point where the firing assembly 103 and the barrel 102 are connected together. That is, at the point where the firing assembly locking feature 110 and the barrel locking feature 112 are engaged.

[0116] After the firing assembly has been connected to the barrel 102, further rotation of the second portion 124 relative to the first portion 122 causes the barrel follower 128 of the second portion 124 to travel on the inclined surface 126 of the first portion 122. This causes the second portion 124 to move rearward relative to the first portion 122. Since the connection point between the firing assembly and the barrel is on the second portion 124, the rearward movement of the second portion 124 also causes the connection point to move rearward, and thus causes the plunger rod 104 to move rearward. In this way, the plunger rod 104 moves rearward relative to the stopper to define the gap between the plunger rod 104 and the stopper. Figure 4c The relative positions of the first part 122 and the second part 124 are shown when the driven part 128 of the second part 124 has passed the inclined surface 126 of the first part 122 and the second part 124 has moved axially rearward relative to the first part 122.

[0117] Those skilled in the art will understand that the plunger assembly 100 described above allows for defining a constant interval between the plunger rod 104 and the stopper in the syringe 360, regardless of the fill space of the syringe 360. This is because the plunger rod 104 first contacts the stopper, then connects to the barrel, and then the barrel moves axially rearward a predetermined distance. Thus, the plunger assembly 100 can be used with syringes of various fill spaces.

[0118] It should be noted that many of the features of the exemplary plunger assembly described above and shown in the accompanying drawings can be included in other exemplary devices. Thus, different drawings are not necessarily considered separate embodiments, and features from one drawing can be transferred to a device in another drawing. Other plunger assemblies and their features will be conceived by those skilled in the art without departing from the scope of the appended claims.

Claims

1. A plunger assembly for use with an automated injection device, the plunger assembly comprising: cylinder; as well as A firing assembly includes a plunger rod, a drive section, and a delivery driver disposed between the plunger rod and the drive section, and configured to forward-bias the plunger rod relative to the drive section. The plunger rod is connected to the drive section, and the firing assembly is axially movable relative to the cylinder. The drive portion is configured to connect to the cylinder at one of a plurality of connection points along the length of the cylinder when the plunger rod is connected to the drive portion, so as to fix the axial position of the plunger rod relative to the cylinder, thereby defining the axial length of the plunger assembly. The plunger rod can be released from the drive section to allow the delivery driver to drive the plunger rod forward relative to the drive section.

2. The plunger assembly according to claim 1, wherein, The firing assembly is retractably housed within the cylinder.

3. The plunger assembly according to claim 1 or 2, further comprising a firing assembly locking feature configured to engage with a barrel locking feature for connecting the firing assembly to the barrel.

4. The plunger assembly according to claim 3, wherein, The firing assembly locking feature is configured to engage with the barrel locking feature during relative rotation between the firing assembly and the barrel.

5. The plunger assembly of claim 1 or 2, further comprising an actuator axially connected to the cylinder such that an axial force applied to the actuator inserts the cylinder into the automated injection device. in, The axial connection is configured to be overcome when the forward movement of the cylinder is prevented due to the continued application of the axial force. Furthermore, the actuator also includes a barrel connector configured to connect the firing assembly to the barrel when the axial force continues to be applied.

6. The plunger assembly according to claim 5, wherein, One of the actuator and the cylinder includes an inclined surface configured to interact with a locking follower on the other of the actuator or the cylinder to convert the axial force, which will continue to be applied, at least partially into a rotational force, and wherein the inclined surface and the locking follower are configured to provide the axial connection.

7. The plunger assembly according to claim 5, wherein, The actuator includes a sleeve configured to receive the cylinder within the sleeve.

8. An automated injection device subassembly comprising a plunger assembly according to any one of claims 1 to 7, and further comprising a housing configured to receive the plunger assembly.

9. The automatic injection device subassembly of claim 8, the automatic injection device subassembly including an axial end stop configured to prevent further forward movement of the plunger assembly.

10. The automatic injection device sub-assembly according to claim 9, wherein, The housing is configured to receive the syringe, and the housing is also configured to position the syringe such that at least a portion of the syringe forms the axial end stop.

11. The automated injection device subassembly according to any one of claims 8 to 10, wherein, The housing is configured to receive a syringe, the syringe including a tube and a stopper located in the tube, wherein the connection point is positioned such that the forward end of the plunger rod contacts the stopper.

12. An automatic injection device comprising a plunger assembly according to any one of claims 1 to 7.

13. An automated injection device comprising an automated injection device sub-assembly according to any one of claims 8 to 11.

14. A method of assembling an automated injection device sub-assembly for use with an automated injection device, the method comprising: A plunger assembly is at least partially inserted into the tubing of a syringe. The plunger assembly includes a barrel and a firing assembly. The firing assembly includes a plunger rod, a drive portion, and a delivery driver disposed between the plunger rod and the drive portion. The delivery driver is configured to forward bias the plunger rod relative to the drive portion, wherein the plunger rod is connected to the drive portion, and wherein the firing assembly is axially movable relative to the barrel such that the forward end of the plunger rod encounters a plug located within the tubing. When the plunger rod is connected to the drive portion, the drive portion is connected to the cylinder at one of a plurality of connection points along the length of the cylinder to fix the axial position of the plunger rod relative to the cylinder, thereby defining the axial length of the plunger assembly. The plunger rod can be released from the drive portion to allow the delivery driver to drive the plunger rod forward relative to the drive portion.

15. The method according to claim 14, wherein, The firing assembly further includes a firing assembly locking feature, and wherein connecting the firing assembly to the barrel includes engaging the firing assembly locking feature with a barrel locking feature on the barrel.

16. The method according to claim 15, wherein, Engaging the firing assembly locking feature with the barrel locking feature includes rotating at least one of the firing assembly and the barrel relative to the other of the firing assembly and the barrel.

17. The method according to any one of claims 14 to 16, wherein, The plunger assembly further includes an actuator axially connected to the cylinder, and the method further includes: The cylinder is inserted into the automatic injection device by applying an axial force to the actuator, preventing the cylinder from moving further forward. An axial force is continued to be applied to the actuator while preventing the cylinder from moving further forward, so that the axial connection between the actuator and the cylinder is overcome, and the cylinder connector of the actuator connects the firing assembly to the cylinder.

18. The method according to claim 17, wherein, The axial connection includes an inclined surface on the actuator or the barrel, the inclined surface being configured to interact with a locking follower on the other of the actuator or the barrel, and wherein continued application of an axial force to the actuator causes the axial force to be at least partially converted into a rotational force to connect the firing assembly to the barrel.

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