Automatic injection device

Abstract

Aspects of the present invention relate to an injection device, which includes: a housing configured to accommodate a syringe; an actuating member; a drive mechanism configured to: when actuated by the actuating member, drive a plunger driver between an initial first position and a final second position, thereby operating a syringe located in the housing; and a damping mechanism, which is configured to damp the movement of the plunger driver in a forward or backward motion. This allows for tolerances in the position of the plunger. The plunger position can affect the amount of travel of the plunger driver before the plunger driver contacts the plunger and the plunger contacts the medicament in the barrel. During this travel, the driving force can cause rapid acceleration of the plunger driver, which can cause damage to the syringe or discomfort to the injection recipient when the three elements contact each other. Damping the forward movement of the plunger driver reduces or overcomes this risk.

Description

Technical Field

[0001] The present disclosure relates to an injection device. In particular, the present invention relates to an injection device in which the movement of a plunger driver is damped. Background Art

[0002] Typically, the delivery of a drug is automatic, where the user performs an action that causes the drug to be delivered without the user performing any further action. An automatic injection device that provides the drug in this manner includes a syringe, or can accommodate a syringe. A syringe generally includes: a barrel for containing the drug; a needle end with a needle, or a device for accommodating a needle; and a plunger at the other end. When the plunger of the syringe is pressed, the plunger moves towards the needle end of the syringe, causing the drug to be ejected from the syringe.

[0003] An automatic injection device generally includes a plunger driver that is configured to drive the plunger of the syringe towards the needle end of the syringe. The plunger driver can be driven towards the needle by a drive spring. The drive spring and the driver can be actuated by the operation of a button or a trigger or the movement of a shield. Summary of the Invention

[0004] According to one aspect of the present invention, there is provided an injection device including: a housing configured to accommodate a syringe; an actuating member; a drive mechanism configured to drive the plunger driver between an initial first position and a final second position when actuated by the actuating member, thereby operating the syringe located within the housing; and a damping mechanism configured to damp the movement of the plunger driver in forward or backward movement. In this way, tolerances in the plunger position can be taken into account. The plunger position can affect the travel amount of the plunger driver before the plunger driver contacts the plunger and the plunger contacts the medicament within the barrel. During this travel, the driving force can cause rapid acceleration of the plunger driver, which can subsequently cause damage to the syringe or discomfort to the injection recipient when the three elements come into contact with each other. Damping of the forward movement of the plunger driver reduces or overcomes this risk.

[0005] The damping mechanism can be configured to damp an initial portion of the movement of the plunger driver.

[0006] The damping mechanism is configured to damp the movement of the plunger driver from the first position to the second position (i.e., from the pre-tensioned position to the position where all the medicament has been delivered). This helps to reduce the vibration effect and wear of the components of the automatic injection device, thereby extending its service life.

[0007] The damping mechanism can be configured to damp the backward movement of the plunger driver. This prevents the door from closing suddenly if it is released during the opening and preloading of the drive mechanism.

[0008] The damping mechanism can be a rotary damper or a linear damper.

[0009] The damping mechanism can be a rack and pinion device, wherein the rotation of the pinion is damped in at least one direction. The pinion can be coupled to the plunger driver, and the rack can be coupled to the housing. The rack can extend along a portion of the housing at the first position and / or along a portion of the housing near the first position to damp an initial portion of the movement of the plunger driver. Alternatively or additionally, a rack can be provided that extends along a portion of the housing at the second position and / or along a portion of the housing near the second position to damp a final portion of the movement of the plunger driver. Optionally, the rack extends between the first position and the second position to damp the entire movement area of the plunger driver after actuation.

[0010] The rotation of the pinion is damped such that when the plunger driver moves from the first position to the second position, the movement of the plunger driver is damped; and when the plunger driver moves from the second position to the first position, the movement of the plunger driver is not damped. This reduces the energy or force required to move the plunger driver back to the preloaded position, where the plunger driver can deliver the drug in the syringe.

[0011] The damping mechanism includes a friction device for applying friction to the plunger driver. The friction device includes surfaces having one or more different coefficients of friction, which are positioned such that the surfaces contact the plunger driver and / or a component coupled to the plunger driver at least during the movement of the plunger driver from the first position to the second position. The coefficient of surface friction can vary gradually at one or more points to be able to gradually increase the damping on the plunger driver and thus eliminate any sudden forces that may be applied to the plunger damper. The surface has a region of greater coefficient of friction at the first position and / or near the first position to damp an initial portion of the movement of the plunger driver. The surface has a region of greater coefficient of friction at the second position and / or near the second position to damp a final portion of the movement of the plunger driver.

[0012] The friction device includes a friction area and a recess, wherein the friction area contacts the plunger driver and / or a component coupled to the plunger driver at least during the movement of the plunger driver from the first position to the second position, and the recess does not provide friction to the plunger driver and / or a component coupled to the plunger driver during the movement of the plunger driver from the first position to the second position.

[0013] The friction device is capable of moving between a position where it damps the movement of the plunger driver and / or a component coupled to the plunger driver when the plunger driver moves between the first position and the second position, and a position where it does not damp the movement of the plunger driver and / or a component coupled to the plunger driver when the plunger driver moves between the first position and the second position. For example, a friction surface can be provided on the door of the device.

[0014] The damping mechanism can include a damping arm pivotally mounted in the housing and in a position where the damping arm contacts the plunger driver when the plunger driver moves from the first position to the second position. In addition to the damping arm, the damping mechanism can further include a return arm pivotally mounted in the housing and in a position where the return arm contacts the plunger driver when the plunger driver moves from the second position to the first position; the damping arm and the return arm are coupled such that the rotation of one causes the rotation of the other. The damping arm and the return arm are coupled perpendicular to each other. When the rotation of the damping arm is caused by contact with the plunger driver, the rotation of the damping arm is damped, and when the rotation of the damping arm is caused by the rotation of the return arm, the rotation of the damping arm is not damped. Description of the Drawings

[0015] One or more embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which:

[0016] Figure 1a and Figure 1b A perspective view of an auto-injection device is shown.

[0017] Figure 2a A cross-section through the auto-injection device is shown.

[0018] Figure 2b An exploded view of the auto-injection device is shown.

[0019] Figure 3 An exemplary damper for an auto-injector is shown.

[0020] Figures 4a to 4gShows a cross-section of an auto-injector device in various operating stages.

[0021] Figures 5a to 5b Shows a perspective view of an alternative auto-injector device.

[0022] Figure 5c Shows a perspective view of an alternative auto-injector device undergoing pre-tensioning.

[0023] Figure 6a Shows a perspective view of the alternative auto-injector device after pre-tensioning.

[0024] Figure 6b Shows a perspective view of the alternative auto-injector device during actuation.

[0025] Figure 7a and Figure 7b Shows a perspective view of another auto-injector device. Detailed Description

[0026] Generally, exemplary methods and devices for auto-injector devices are disclosed herein, and in some particular arrangements, the auto-injector device is a safety auto-injector device. The term "auto-injector device" is used herein and may be considered to cover both auto-injector devices and safety auto-injector devices where appropriate. An auto-injector device may be configured to accommodate and operate a standard syringe (i.e., not a safety syringe) and / or a safety syringe. A syringe typically includes a barrel that houses a drug. At the front end of the syringe is a needle or a device for accommodating a needle. At the rear end of the syringe is a plunger. The plunger is typically made of an elastomeric material, and applying pressure on the plunger causes the drug contained in the syringe to be ejected from the syringe via the needle.

[0027] Although the auto-injector device described herein is a reusable auto-injector device, it should be understood that the methods described below also apply to single-use auto-injector devices where the plunger driver may not be actuated again. The described methods also apply to any injection device where the delivery of the drug is automatic rather than manual.

[0028] In the following embodiments, the terms "forward" and "front" refer to the end of the injection device or a component of the injection device that faces the patient. In other words, the front end of the injection device is the end that is close to the injection site during use. Similarly, the term "rear" refers to the non-patient end of the injection device assembly or a component of the injection device assembly. In other words, the term "rear" refers to being away from the injection site or being farther from the injection site during use. Additionally, the term "longitudinal" is used to cover a direction along the longitudinal axis of the injection device or a direction parallel to the longitudinal axis of the injection device.

[0029] The features of the exemplary arrangements disclosed herein are described as being "coupled" to other features. The term encompasses any coupling that causes the coupled features to move together in any direction, whether on a 1:1 basis or on some gear ratio basis. The term "coupled" also encompasses any of a connection between features, an abutment of one feature against another feature, and an engagement of one feature with another feature, and such coupling can be direct or can be indirect, i.e., there is a third feature between the features.

[0030] Figure 1a and Figure 1b An exemplary auto-injector device 100 for accommodating and operating a syringe 102 is shown. The auto-injector device includes a housing, which further includes a plurality of component parts. In Figure 1a and Figure 1b the example, the housing includes a body 104, a hinged door 106 (referred to herein as the "door") and a rear body 108 in some exemplary arrangements. Figure 1a An auto-injector device 100 is shown with the door 106 in the closed position, Figure 1b An auto-injector device 100 is shown with the door 106 in the open position. The door 106 is operable between these two positions. It can be seen that when the door 106 is in the open position, the syringe 102 can be accommodated within the housing and, in this case, specifically within the body 104. The door 106 can 30 include a hinged connection 110 to the body 104.

[0031] Two charging links 112a, 112b connect the door 106 to the body 104. The connections between the charging links 112a, 112b and the body 104 are slidable and / or the connections between the door 106 and the charging links 112a, 112b are slidable. This allows the door 106 to be opened about the hinged connection 110. In Figure 1a and Figure 1b the example shown, the connections between the charging links 112a, 112b and the body 104 are slidable.

[0032] The auto-injector device 100 also includes at least one drive spring and, in Figure 1a and Figure 1b the case, includes two drive springs 114a, 114b (the drive spring 114a is not shown in Figure 1a and Figure 1bis shown, but is located at a position similar to the drive spring 114b on the opposite side of the auto-injector device 100). The sliding connection portions of the loading links 112a, 112b with the main body 104 are configured to be coupled to the drive springs 114a, 114b so as to pre-tension the drive springs 114a, 114b by compression of the drive springs 114a, 114b when the door 106 is opened. It will be apparent to those skilled in the art that other arrangements are possible, such as pre-tensioning the drive springs 114a, 114b when the door 106 is closed.

[0033] The auto-injector device 100 further includes spring guides 116a, 116b (the spring guide 116a is not shown in Figure 1a and Figure 1b and is located at a position similar to the spring guide 116b on the opposite side of the auto-injector device 100), in Figure 1a and Figure 1b the illustrated example, the spring guides 116a, 116b include rods. The rods have a cross-sectional shape of a cross. The rods include reaction surfaces 118a, 118b against which the rear ends of the drive springs 114a, 114b are placed. Thus, the extension of the drive springs 114a, 114b generates a force acting in the forward direction.

[0034] The drive springs 114a, 114b are positioned around the rods such that the rods pass through the holes defined by the drive springs 114a, 114b. In this way, the extension and compression of the drive springs 114a, 114b follow the paths defined by the spring guides 116a, 116b. Those skilled in the art will understand that other forms of spring guides can be used.

[0035] The slidable connection portions of the loading links 112a, 112b can be provided by loading linkages 120a, 120b. The loading linkages 120a, 120b are rotatably connected to the loading links 112a, 112b and are configured to slide along the spring guides 116a, 30 116b. In Figure 1a and Figure 1b the case, the loading linkages 120a, 120b include holes through which the spring guides 116a, 116b (e.g., rods) pass.

[0036] The auto-injector device 100 further includes two plunger drivers 122a, 122b, but the plunger drivers 122a, 122b are not shown in Figure 1a and Figure 1bIt is not easily visible in the front, but can be well seen in the subsequent drawings, where the operations of the plunger drivers 122a and 122b are fully described. Broadly, the plunger drivers 122a and 122b are connected or otherwise coupled to the ends of the drive springs 114a and 114b such that the extension of the drive springs 114a and 114b drives the plunger drivers 122a and 122b forward. The plunger drivers 122a and 122b are arranged to contact the plunger of the syringe 102, thereby driving the plunger forward and operating the syringe 102.

[0037] The auto-injection device 100 further includes a shield. In Figure 1a and Figure 1b exemplary arrangements, the shield includes a body portion 130 and a door portion 132. The body portion 130 is slidably connected to the body 104. The door portion 132 is slidably connected to the door 106. Thus, and as Figure 1b shown, when the door 106 is in the open position, the shield is separated. This allows the syringe 102 to be loaded into the auto-injection device 100 from the top without passing the needle end of the syringe 102 through the shield. The body portion 130 and the door portion 132 also include bonding features that are configured to interlock when the door 106 is in the closed position. This longitudinally couples the body portion 130 to the door portion 132, and then the body portion 130 and the door portion 132 can move longitudinally together. A shield spring biases the shield in the forward direction.

[0038] The body 104 includes one or more recessed areas that represent "ghosted" impressions of the syringe 102. For example, the body may include a recess 134 that is configured to receive the handle portion 136 and the finger flange 138 of the syringe 102. Additionally, the body 104 may include a recess 140 that is configured to receive the extended plunger assembly 142 of the syringe 102. The length of the recess 140 takes into account the tolerance of the plunger position of the pre-filled syringe.

[0039] Figure 2a and Figure 2b respectively show a cross-section of the auto-injection device 100 and an exploded view of the auto-injection device 100. In Figure 2a and Figure 2b are also shown a plurality of the features that have been discussed with respect to Figure 1a and Figure 1b discussed.

[0040] Referring to Figure 2a and Figure 2b, the body 104 includes one or more driver latches 144. For the remainder of this part of the specification, features on one side of the longitudinal axis of the auto-injector device 100 will be referred to. However, the same features and related descriptions may be associated with the opposite side of the longitudinal axis. The driver latch 144 is configured to prevent the 10 plunger driver 122 from moving forward. The driver latch 144 includes a protrusion 146 that extends transversely to the longitudinal axis from an elastically deformable arm 148. The protrusion 146 includes a forward-facing inclined surface 152 and a rear-facing latch surface 150 that extend laterally in the direction of the elastically deformable arm 148. In the rest position of the elastically deformable arm 148, under the influence of the drive spring 114, the protrusion is in the 15 path followed by the plunger driver 122. The plunger driver 122 includes a protrusion 154 that extends transversely to the longitudinal axis of the auto-injector device. The protrusion 154 includes a rear-facing inclined surface 156 and a forward-facing abutment surface 158. The abutment surface 158 is arranged to abut the latch surface 150 when the plunger driver 122 is held by the driver latch 144.

[0041] The body 104 further includes a sheath latch 159, which includes a protrusion 160 that protrudes transversely along the elastically deformable prong 162 and transversely to the longitudinal axis of the auto-injector device 100. The protrusion 160 includes a rear-facing inclined surface 164 and a forward-facing latch surface 166. The shield and the body portion 130 of the shield in the exemplary arrangement of FIGS. 1 to 2 include a rearwardly extending latch release arm 168. The rearward movement of the shield and thus the latch release arm 168 is configured to release the driver latch 144. In the example shown in the figure, this is achieved by the drive release surface 170. As described below, the drive release surface 170 passes over the rear-facing inclined surface of the driver latch 144 to release the driver latch 144 and allow the forward movement of the plunger driver 122.

[0042] The latch release arm 168 also includes a hole or recess 172 in which the protrusion 160 of the sheath latch 159 is received before the operation of the auto-injector device 100. This represents the rest position of the elastically deformable prong 162. In the rest position of the prong 162, the protrusion 160 is outside the path of the plunger driver 122 and is thus allowed to pass through. The rear surface (or shield release surface) 174 of the hole 172 is configured to engage the latch by passing over the inclined surface 164 of the protrusion 160 when the shield moves rearward. The subsequent forward movement of the shield allows the protrusion 160 to re-enter the hole 172 under the force of the prong 162, thereby releasing the latch.

[0043] Figure 3An exemplary damper 400 assembled to an auto-injector device 100 is shown. The damper 400 can be configured to damp the forward and / or backward movement of a plunger driver 122. In one example, the damper 400 is configured to damp at least an initial stage of the forward movement of the plunger driver 122. This initial stage can reach 15 mm, reach 10 mm, or reach 5 mm. In this way, tolerances in the plunger position are taken into account. The plunger position can affect the overall length of the auto-injector device 100 and / or affect the amount of travel of the plunger driver 122 before the plunger driver contacts the plunger and the plunger contacts the medicament within the barrel. During this travel, spring force may cause the plunger to accelerate rapidly, which can cause damage to the syringe or discomfort to the injection recipient when the three elements come into contact with each other. Damping of the forward movement of the plunger driver 122 reduces or overcomes this risk.

[0044] The damper 400 can also be configured to operate on a more forward travel of the plunger driver 122, and in some arrangements, the damper 400 can operate on the entire forward travel of the plunger driver. This can reduce the vibration effect and wear of the components of the auto-injector device, thereby extending its lifespan.

[0045] In addition, the damper 400 can damp the backward travel of the plunger driver 122. This can prevent the door 106 from closing suddenly if the door 106 is released during the opening and pre-tensioning of the drive spring 114.

[0046] In Figure 3 an example, the exemplary damper 400 includes an arrangement of a rack 402 and a pinion 404. The pinion 404 is connected to the plunger driver and travels along the rack 402 as the plunger driver 122 moves forward or backward. The pinion 404 is configured to have damped rotation in one or both directions to damp the travel of the plunger driver 122.

[0047] Now refer to Figures 4a to 4g the operation of the auto-injector device. In Figure 4aIn [description], the hinged door 106 is opened about the hinge connection 110. This causes the loading linkage 120 of the loading link 112 to slide along the spring guide 116. When the door 106 is opened after the operation of this device, the drive spring 114 will extend along the spring guide 116 before opening. Thus, the loading linkage 120 is coupled (in this case, abutted) to the drive spring 114 during the opening of the door 106. The leverage of the door 106 allows the user to obtain a mechanical benefit in pre-tensioning the drive spring 114. This can be particularly beneficial when using high-force springs, for example when the medicament to be delivered by the auto-injection device has a high viscosity. In some examples, the viscosity of the medicament can be in the range of 12 centipoise (cP) to 18 cP, in the range of 14 cP to 16 cP, or can be 15 cP. Additionally, the drug may need to be delivered through a thin-walled needle of gauge 29, but needles of other gauges can also be used. This requires a relatively high spring force, such as 40 N to 50 N, which can be 45 N, which may make it difficult for the user to perform the pre-tensioning.

[0048] During the opening of the door 106, the loading linkage 120 compresses the drive spring 114 and moves the plunger driver 122 backward. The rearwardly inclined surface 156 of the plunger driver 122 contacts the forwardly inclined surface 152 of the driver latch 144 and laterally displaces the protrusion 146 to allow the plunger driver 122 to pass through. After the plunger driver 122 passes through, the protrusion 146 springs back into the path of the plunger driver 122 under the force of the elastic arm 148. Thus, the plunger driver 122 is latched.

[0049] The door portion 132 moves with the door 106, thereby allowing the syringe 102 to be laterally received into the auto-injection device without passing the needle tip through the shield.

[0050] In Figure 4b In [description], the syringe 102 is inserted into the body 104 using the ghost recesses 134, 140 and the receiving tray 126. Then, the door 106 is closed about the hinge connection 110. The loading linkage 120 slides forward along the spring guide 116. The plunger driver 122 is held by the driver latch 144, and the drive spring 114 does not extend along the spring guide 116. Thus, there is a space on the spring guide 116 into which the drive spring 114 can extend when the auto-injection device 100 is operated. The door portion 132 of the shield is connected to the main body portion 130 of the shield by bonding features such that the door portion 132 and the main body portion 130 of the shield are longitudinally coupled or connected.

[0051] Figure 4cIt shows that the cap 124 is being removed. The deformable fork 128 that houses the tray 126 is stuck on the RNS of the syringe 102, so the RNS is also removed. The cap 124 includes a hole through which the RNS falls after the needle is removed.

[0052] As can be seen in Figure 4d , the main body part 130 and the door part 132 of the shield surround the needle and extend beyond the front end of the needle, so the needle is shielded and protected. Under the action of the force of the shield spring, the shield is biased in the forward direction. The driver latch 144 is engaged and thus located in the path of the plunger driver 122. In addition, the sheath latch 159 is received in the hole 172 of the latch release arm 168 and is outside the path of the plunger driver 122.

[0053] In Figure 4e , the shield is pushed backward into the auto-injection device 100. This can be done by the user pressing the shield against the injection site. This action exposes the needle, allowing the needle to enter the injection site. In other arrangements, the syringe 102 can move forward within the syringe carrier under the action of a spring force. In such an arrangement, the backward movement of the shield (or actually the pressing of the button) can release the spring, thereby driving the syringe carrier forward for needle insertion.

[0054] The forward-facing drive release surface 170 of the latch release arm 168 passes over the backward-facing inclined surface of the protrusion 146 of the driver latch 144. This laterally displaces the protrusion 146 out of the path of the plunger driver 122 (in Figure 4e , displaced to the left). This action can be seen in circle A in Figure 4e . Moreover, the backward movement of the shield causes the shield release surface 174 of the hole 172 in the latch release arm 168 to pass over the backward-facing inclined surface 164 of the protrusion 160 of the sheath latch 159. This laterally displaces the protrusion 160 into the path of the plunger driver 122 (in Figure 4e , displaced to the right). This action can be seen in circle B.

[0055] The separation of the driver latch 144 releases the drive spring 114, which drives the plunger driver forward, thereby driving the plunger of the syringe 102 into the barrel. This forces the plunger further into the barrel and dispenses the medicament (or other substance) from the syringe 102. In some arrangements, the movement of the plunger driver 122 can be damped, especially during the initial stage of the forward stroke. This will be described in more detail below.

[0056] The plunger driver 122 is driven forward until the plunger driver 122 reaches the sheath latch 159, at which point the sheath latch 159 is engaged and lies in the path of the plunger driver 122. Thus, the sheath latch 159 stops the forward movement of the plunger driver 122. The sheath latch 159 can be positioned such that the plunger driver 122 is stopped at a point on its forward stroke at which all of the dose of medicament has been delivered from the cartridge, or at a point thereafter. The exemplary arrangement shown in the figures is configured for use with a safety syringe, where further movement of the plunger after all of the dose has been delivered deploys the shield in order to protect the needle after use of the syringe 102. Thus, stopping the forward movement of the plunger driver 122 prevents deployment of the shield. It should be understood that the sheath of the safety syringe can also be deployed under the force of a separate spring, which can be released by a sheath release mechanism. Such a mechanism can be released by forward movement of the plunger (or plunger driver 122) after all of the dose has been delivered. Such an arrangement is included within the embodiments disclosed herein.

[0057] After all of the dose has been delivered, the user lifts the auto-injector device away from the injection site. As Figure 4g shown, under the force of the shield spring, the shield is thus urged forward. The forward movement of the shield causes the latch release arm 168 to move forward until the aperture 172 is longitudinally aligned with the protrusion 160. Thus, the protrusion 160 enters the aperture 172 under the force of the fork 162. This disengages the sheath latch 159 and moves the protrusion 160 out of the path of the plunger driver 122, thereby allowing the plunger driver 122 to move forward. Further forward movement of the plunger driver 122 causes the plunger of the auto-injector device 100 to move further forward, thereby deploying the shield. At this point the door 106 can be opened, the drive spring 114 pre-tensioned again, and the sheathed safety syringe 102 removed.

[0058] In some arrangements, multiple drive springs 114 may be located on the auto-injector device 100. One or more of the multiple drive springs 114 may be configured to be in an active state or a passive state. That is, one or more of the drive springs 114 may be configured to either drive or assist in driving the plunger driver 122 forward, or to impede the driving of the plunger driver 122 forward. The configuration may include removing one or more of the drive springs 114 from the auto-injector device 100. This may be done during the assembly of the auto-injector device 100. In other arrangements, settings on the auto-injector device may configure one or more of the drive springs 114. For example, one of the loading links 112 may be disconnected from the door 106. The above-described drive springs include two tension springs, however, those skilled in the art will understand that the drive springs may be any other suitable biasing member. Including but not limited to tension springs, compression springs, or torsion springs.

[0059] Figures 5a to 6b A perspective view of an alternative auto-injector device for housing and operating a syringe (not shown) is shown. In these figures, unless otherwise indicated, like features operate as described with reference to FIGS. 1 - 4. Like features maintain the last two digits of the reference numeral the same.

[0060] As previously described, the auto-injector device 500 includes a drive spring 514. The drive spring 514 is configured to drive the plunger of a syringe housed within the auto-injector device 500 forward in order to dispense fluid from the syringe.

[0061] The auto-injector device 500 also includes at least one biasing member 509 configured to bias the hinged door 506 towards a pre-tensioned position. As described below, the biasing member 509 assists in the pre-tensioning of the drive spring 514 of the auto-injector device 500 by providing an auxiliary force to help the user move the hinged door 506 to its pre-tensioned position in preparation for use.

[0062] The biasing member 509 may include one or more springs, and the springs may be tension springs, compression springs, torsion springs, or other types of springs. In Figure 5a and Figure 5b example, the biasing member 509 includes two torsion springs that are coupled to the hinged door 506 and the body 504 around the hinge connection 510. During the opening movement and / or closing movement of the hinged door 506, the relative movement between the hinged door 506 and the body 504 around the hinge 103 causes the torsion springs to twist. In Figure 5a and Figure 5bIn the example, the hinged door 506 is opened to load the syringe into the auto-injector device 500, pre-tensioning the torsion spring. When the hinged door 506 is in the unpre-tensioned position, the torsion spring 509 is pre-tensioned. The torsion spring acts on the hinged door 506 to apply a torque to bias the hinged door 506 towards its pre-tensioned position (in this case the closed position).

[0063] In Figure 5a and Figure 5b the example, opening the hinged door 506 causes the drive spring 514 to translate rearward without pre-tensioning the drive spring 514. Thus, the opening movement of the hinged door 506 allows the syringe to be loaded into the auto-injector device 500 before pre-tensioning. Before closing the hinged door 506, the end of the tension spring of the plunger driver is held in place relative to the body 504. When closing the hinged door 506 that is rotatably connected to the loading link 512, the hinged door 506 is pushed forward. Subsequently, due to the slidable connection of the loading link 512 with the body 504 and since the loading link 512 is coupled to the opposite end of the tension spring, the loading link 512 slides along the body 504 and thereby extends the tension spring of the drive spring 514, as shown later in Figure 5c shown.

[0064] Each loading link 512 can be coupled to a shuttle 511. The shuttle 511 can slide along the body 504 and is configured to travel along a shuttle guide 513. The shuttle guide 515 can be the same as the spring guide 116 described previously or can be provided as a separate component. The loading link 512 and the shuttle 511 are connected, and this connection can be rotatable. In some arrangements, the shuttle 511 provides a slidable connection of the loading link 512 with the body 504.

[0065] The shuttle 511 includes a first pre-tensioning portion 515 and a second pre-tensioning portion 517. The (one or more) drive springs 514 are connected between the first pre-tensioning portion 515 and the second pre-tensioning portion 517. As Figure 5b shown, when the door 516 is opened, the first pre-tensioning portion 515 and the second pre-tensioning portion 517 are configured to travel together along the shuttle guide 515 towards the hinge connection. Since the (one or more) drive springs 514 are connected between the first pre-tensioning portion 515 and the second pre-tensioning portion 517, this movement does not pre-tension the drive springs 514.

[0066] The body 504 and / or the first pre-tensioning portion 515 can include a latch configured to hold the first pre-tensioning portion 515 in place on the shuttle guide 513 after opening the hinged door 506. After opening the hinged door 506, the first pre-tensioning portion 515 and the second pre-tensioning portion 517 are separable. AsFigure 6a As shown, the second pre-tensioning portion 517 is configured to travel along the shuttle guide 513 away from the hinge connection 510 when the door 506 is closed. Since the (one or more) drive springs 514 are connected between the first pre-tensioning portion 515 and the second pre-tensioning portion 517, when the second pre-tensioning portion 517 travels forward, the (one or more) drive springs 514 are pre-tensioned to provide a delivery force to the plunger driver and thereby deliver the drug from the syringe.

[0067] As described above, the first pre-tensioning portion 515 and the second pre-tensioning portion 517 are configured to travel together along the shuttle guide 513 when the door 506 is open, and the first pre-tensioning portion 515 and the second pre-tensioning portion 517 are separable such that the second pre-tensioning portion 517 separates from the first pre-tensioning portion 515 and the second pre-tensioning portion 517 travels along the shuttle guide 513 when the door 506 is closed. This separated state is shown in Figure 6a ...

[0068] Figure 6a A bottom view of the auto-injector device 500 in the pre-tensioned state is shown, where the hinged door 506 is closed and the drive spring 514 has been pre-tensioned. The drive spring 514 is held in its pre-tensioned state by latching the first pre-tensioning portion 515 in place. In the example of Figure 4a ..., the drive spring 514 includes two tension springs that are fully extended.

[0069] Figure 6b A perspective view of the bottom side of the auto-injector device 500 during actuation is shown. The drive spring 514 is configured to drive the plunger driver forward within the auto-injector device 500 during actuation to operate the syringe housed within the auto-injector device 500. In the example of Figure 6b ..., the tension springs act together to provide the forward force required to inject the medicament in the installed syringe into the patient. The plunger driver can be coupled to the drive spring 514 to achieve this purpose.

[0070] The first pre-tensioning portion 515 is provided with two pinions 530. Those skilled in the art will understand that the number of pinions can depend on various factors and thus any number of pinions can be provided, including one pinion. The pinions are located on a rack (not shown), such as the rack previously Figure 3 shown. The rack is located on the body 504, for example in the hole 533 that can be seen in Figure 5a ...

[0071] The pinions 530 are connected to the drive spring 514 via the first pre-tensioning portion 515. As Figure 6bAs shown, when the auto-injection device is actuated, the drive spring 514 moves forward in the auto-injection device. When the first pre-tension portion 515 is coupled to the drive spring, the first pre-tension portion 515 also travels along the rack as the drive spring moves. When the first pre-tension portion 515 moves forward, the pinion moves along the rack, thereby damping the forward movement of the plunger driver (not shown) via the drive spring 514.

[0072] As will be understood by those skilled in the art, a rack as shown may be present over the entire travel length of the plunger driver or a rack as described with reference to Figure 3 shown. Alternatively, a rack may be present along a portion of the body corresponding to an initial portion of the movement of the plunger driver or a final portion of the movement of the plunger driver. Figures 5a to 6b Damping the initial portion of the movement of the plunger driver serves to reduce the acceleration of the plunger driver, thereby causing the plunger driver to contact the plunger with a smaller force than if the plunger driver were not damped. For example, this helps with the use of syringes having different plunger positions. For example, when the plunger driver is moving at a low speed and the plunger driver is still accelerating, a syringe having a plunger further away from the needle end of the syringe will be contacted. In contrast, when the plunger driver is moving at its end speed, a syringe having a plunger closer to the needle will be contacted, and a large amount of force is required when the speed of the plunger driver slows down due to contacting the plunger. By using a damper (e.g., the damper described above), the increase in the speed of the plunger driver is slowed down, so the force to be consumed when the plunger meets the plunger is reduced.

[0073] Damping the final portion of the movement of the plunger driver can be beneficial in reducing the speed of the plunger driver before the plunger contacts the end of the syringe. Since this auto-injection device allows the plunger to be driven over the entire length of the syringe while reducing the force when the plunger meets the end of the syringe, this increases the ability of the auto-injection device to deliver all of the drug contained in the syringe. This is beneficial for using drugs having different viscosities, because when the drug has a lower viscosity, the plunger will meet the end of the syringe at a higher speed than when the drug has a higher viscosity. By reducing the speed at which the plunger meets the end of the syringe, the force when the plunger meets the end of the syringe can be reduced.

[0074] Optionally, the pinion may be configured to have damped rotation in one or both directions to damp the travel of the plunger driver. By reducing the backward movement of the plunger driver, wear of the components within the auto-injection device is reduced.

[0075]

[0076] ​Although the present invention has been described with reference to a damping mechanism of a rack and pinion, those skilled in the art will understand that any suitable linear damper and / or rotary damper can be used.

[0077] In another example, damping can be provided by providing an area of greater friction to slow down the movement of the plunger driver. For example, a friction area can be provided over an area of the shuttle guide 513. The friction area is configured to slow down the acceleration of the first pre-tensioned portion 515 when the auto-injection device is actuated. Alternatively, the friction area can replace all or part of the previously described track with a plunger driver provided with a device that contacts the friction area.

[0078] The friction area can, for example, be provided on the track such that the plunger driver or a component coupled to the plunger driver can be continuously in proximity. In this case, the area can be provided with an elastomeric material and an area that is not a friction area, the area that is not a friction area being provided with a surface having a coefficient of friction lower than that of the friction area. Alternatively, the track can be such that the plunger driver or a component coupled to the plunger driver only contacts the track when damping is required. For example, when damping is not required, the track can include a recess. The area of the track can be provided with any suitable surface to provide the desired slowdown of the acceleration. For example, as previously described, the surface of the track can be provided with an elastomeric material such as rubber.

[0079] When the plunger driver is moved to the pre-tensioned position, the friction surface is able to move away from the plunger driver or the component coupled to the plunger driver in order to reduce the effort required to move the plunger driver to a position where the plunger driver can be actuated again. For example, this can be achieved by mounting the friction surface on a door of the device or by rotating the friction surface away from the piston driver or component.

[0080] In yet another example, as shown in FIGS. 7 and Figure 7b as shown, the acceleration of the plunger driver is slowed down by a mechanical means. In these figures, unless otherwise indicated, similar features operate as described with reference to FIGS. 1 to 6. Similar features maintain the last two digits of the reference numerals the same.

[0081] Figure 7a The drive spring 714 and the plunger driver 722 in a pre-delivery configuration are shown, where the drive spring 714 is pre-tensioned. Figure 7b The positions of the drive spring 714 and the plunger driver 722 after the auto-injection device has been actuated are shown. In Figure 7a and Figure 7bIn the configuration shown, a mechanical member 740 including a coupling member 742 and two vertical arms is used to damp the movement of the plunger driver 722. The coupling member connects the mechanical member to the body 704 and provides a pivot point about which the two vertical arms can rotate.

[0082] When actuating the auto-injector device, the plunger driver 722 moves between Figure 7a the position shown and Figure 7b the position shown. When the plunger driver moves forward, the plunger driver contacts one of the two vertical arms that projects into its path. The contact of the plunger driver with the arm causes the mechanical member to pivot about the coupling member 742 to Figure 7b the position shown. The contact of the plunger driver 742 with the arm of the mechanical member slows down the acceleration of the plunger driver. If the rotation of the arm about the coupling member is damped, the acceleration can be further slowed down.

[0083] When the device is to be re-primed, the plunger driver is moved back to the position where the plunger driver can drive the plunger downward to drive the syringe, i.e., when the plunger driver 722 moves from Figure 7b the position shown to Figure 7a the position shown. During this movement, the plunger driver contacts the other arm of the arm, causing the mechanical member to rotate about the coupling member back to its original position. Thereby, the mechanical member is reset, and the mechanical member can damp the forward movement of the plunger driver when the auto-injector device is actuated next time. The rotation of the mechanical member can be damped only in the rotational direction caused by the forward movement of the plunger driver in the auto-injector device, and cannot be damped in the rotational direction caused by the backward movement of the plunger driver in the auto-injector device. This means that no additional force is required when resetting the auto-injector device.

[0084] In the case where the auto-injector device is not a reusable auto-injector device and thus does not require the plunger driver to be moved back to Figure 7a the position shown, it will be understood that the mechanical member 740 can have only a single arm positioned to damp the forward movement of the plunger driver.

[0085] Although the present invention has been described with reference to a hinged door, it will be understood that other door configurations are possible. For example, the body and the door can have a slidable connection.

[0086] Those skilled in the art can conceive of other components, auto-injection devices and their features without departing from the scope of the appended claims. In particular, it should be noted that, as will be understood by those skilled in the art, one or more features included in one or more of the figures can be integrated into the auto-injection devices shown in other figures. It should be understood that the detailed description and specific examples are given by way of illustration only, since various changes and modifications within the spirit and scope of the present disclosure will become apparent to those skilled in the art through this description.

Claims

1. An injection device, comprising: a. a housing configured to receive a syringe and comprising a door; b. Actuating member; c. a drive mechanism configured to, when actuated by the actuation member, drive a plunger driver between an initial first position and a final second position, thereby operating the syringe within the housing; d. a damping mechanism configured to damp the movement of the plunger drive in a rearward motion to control the speed of movement of the door during opening and pretensioning of the drive mechanism, The damping mechanism comprises a friction device comprising surfaces having one or more different coefficients of friction, the surfaces being positioned so that the surfaces are in contact with the plunger driver and / or with a component coupled to the plunger driver at least during movement of the plunger driver from the first position to the second position.

2. The injection device according to claim 1, wherein: The damping mechanism is configured to dampen an initial portion of movement of the plunger driver.

3. The injection device according to claim 1 or 2, wherein: The damping mechanism is configured to dampen movement of the plunger driver from the first position to the second position.

4. The injection device according to any one of claims 1 to 2, wherein: The friction device is used to apply friction on the plunger driver.

5. The injection device according to claim 4, wherein: The surface has a region of greater coefficient of friction at and / or adjacent the first location, thereby damping an initial portion of the movement of the plunger driver.

6. The injection device according to claim 5, wherein: The surface has a region of greater coefficient of friction at and / or adjacent the second position, thereby damping a final portion of the movement of the plunger driver.

7. The injection device according to claim 4, wherein: The friction device includes a friction area and a recess, wherein the friction area is in contact with the plunger driver and / or a component coupled to the plunger driver at least during the movement of the plunger driver from the first position to the second position, and the recess does not provide friction to the plunger driver and / or a component coupled to the plunger driver during the movement of the plunger driver from the first position to the second position.

8. The injection device according to claim 5, wherein: The friction device is capable of moving between a position that dampens the movement of the plunger driver and / or a component coupled to the plunger driver when the plunger driver moves between the first position and the second position, and a position that does not dampen the movement of the plunger driver and / or a component coupled to the plunger driver when the plunger driver moves between the first position and the second position.

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