Automatic injection device

Abstract

An injection device is disclosed, the injection device comprising: a housing configured to receive a syringe; an actuating member; a drive mechanism configured to, when actuated by the actuation member, drive the plunger driver between an initial first position and a final second position to operate a syringe located within the housing; and a damping mechanism configured to damp movement of the plunger driver in the forward movement or the backward movement. In this way, the tolerance of the plunger position can be taken into account. The plunger position may affect an amount of travel of the plunger driver prior to contact of the plunger driver with the plunger and contact of the plunger with medicament within the cartridge. During this travel, the driving force may result in a rapid acceleration of the plunger drive, which may result in damage to the syringe or discomfort to an injection recipient when the three elements are in contact with each other. Damping of forward movement of the plunger drive reduces or overcomes this risk.

Description

[0001] This application is a divisional application with application number 201980064095.4, application date March 29, 2021, and subject matter “Automatic Injection Device”. Technical Field

[0002] 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

[0003] Typically, drug delivery is automatic, where a user performs an action that causes the drug to be delivered without requiring any further action from the user. Automatic injection devices that deliver drugs in this manner include, or can accommodate, a syringe. Syringes typically include: 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 syringe's plunger is depressed, the plunger moves toward the needle end of the syringe, causing the drug to be ejected from the syringe.

[0004] Automatic injection devices typically include a plunger driver for driving the plunger of a syringe toward the needle end of the syringe. The plunger driver may be driven toward the needle by a drive spring. The drive spring and driver may be actuated by operation of a button or trigger or movement of a shield. Summary of the Invention

[0005] According to one aspect of the present invention, an injection device is provided, comprising: a. a housing configured to accommodate a syringe; b. an actuating member; c. 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 the syringe within the housing; and d. a damping mechanism configured to dampen movement of the plunger driver during forward or backward movement.

[0006] The damping mechanism is configured to dampen an initial portion of the motion of the plunger driver.

[0007] The damping mechanism is configured to dampen movement of the plunger driver from the first position to the second position.

[0008] The damping mechanism is configured to dampen rearward movement of the plunger driver.

[0009] The damping mechanism includes a rotary damper or a linear damper.

[0010] The damping mechanism comprises a rack and pinion arrangement, wherein rotation of the pinion is damped in at least one direction.

[0011] The pinion is coupled to the plunger driver, and the rack is coupled to the housing.

[0012] The rack extends along a portion of the housing at the first location and / or along a portion of the housing near the first location to dampen the initial portion of the movement of the plunger driver.

[0013] The rack extends along a portion of the housing at the second position and / or along a portion of the housing near the second position to dampen the final portion of the movement of the plunger driver.

[0014] The rack extends between the first position and the second position so as to dampen the entire range of motion of the plunger driver after actuation.

[0015] The rotation of the pinion is damped so that when the plunger driver is moving from the first position to the second position, the movement of the plunger driver is damped; and when the plunger driver is moving from the second position to the first position, the movement of the plunger driver is not damped.

[0016] The damping mechanism includes a friction device for applying friction on the plunger driver.

[0017] The friction device includes surfaces having one or more different coefficients of friction, which are positioned so that they contact the plunger driver and / or a component coupled to the plunger driver at least during movement of the plunger driver from the first position to the second position.

[0018] The surface has a region of greater coefficient of friction at and / or adjacent the first location, thereby damping the initial portion of the movement of the plunger driver.

[0019] The surface has a region of greater coefficient of friction at and / or adjacent the second position, thereby damping the final portion of the movement of the plunger driver.

[0020] The friction device comprises 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.

[0021] The friction device is capable of moving between a position in which the movement of the plunger driver and / or a component coupled to the plunger driver is damped when the plunger driver moves between the first position and the second position, and a position in which the movement of the plunger driver and / or a component coupled to the plunger driver is not damped when the plunger driver moves between the first position and the second position.

[0022] The damping mechanism includes a damping arm pivotally mounted in the housing and positioned so as to contact the plunger driver when the plunger driver moves from the first position to the second position.

[0023] The damping mechanism also includes a reset arm pivotally mounted in the housing and in a position where the reset arm contacts the plunger driver when the plunger driver moves from the second position to the first position; the damping arm and the reset arm are coupled such that rotation of one causes rotation of the other.

[0024] The damping arm and the return arm are perpendicularly coupled to each other.

[0025] The rotation of the damping arm is damped when the rotation of the damping arm is caused by contact with the plunger driver, and the rotation of the damping arm is not damped when the rotation of the damping arm is caused by rotation of the reset arm.

[0026] According to one aspect of the present invention, an injection device is provided, comprising: a housing configured to accommodate a syringe; an actuating member; a drive mechanism configured to, when actuated by the actuating member, drive the plunger driver between an initial first position and a final second position, thereby operating the syringe located within the housing; and a damping mechanism configured to damp the movement of the plunger driver during forward or backward motion. This allows for tolerances in plunger position. 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 within the barrel. During this travel, the driving force can cause rapid acceleration of the plunger driver, which can subsequently damage the syringe or cause discomfort to the recipient of the injection when the three components come into contact with each other. Damping the forward motion of the plunger driver reduces or overcomes this risk.

[0027] The damping mechanism may be configured to damp an initial portion of the movement of the plunger driver.

[0028] The damping mechanism is configured to dampen movement of the plunger driver from the first position to the second position (i.e., from the preloaded position to the position where all the medicament has been delivered). This helps to reduce the effects of shock and wear on components of the autoinjector, thereby extending its service life.

[0029] The damping mechanism may be configured to dampen the rearward movement of the plunger drive. This prevents the door from closing suddenly if the door is released during the opening and pre-tensioning of the drive mechanism.

[0030] The damping mechanism may be a rotary damper or a linear damper.

[0031] The damping mechanism can be a rack and pinion arrangement, 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 located at the first position and / or along a portion near the first position of the housing to damp the initial portion of the motion of the plunger driver. Alternatively or additionally, a rack extending along a portion of the housing located at the second position and / or along a portion near the second position of the housing can be provided to damp the final portion of the motion of the plunger driver. Alternatively, the rack extends between the first position and the second position to damp the entire motion range of the plunger driver after actuation.

[0032] The rotation of the pinion gear is damped so 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 in which the plunger driver can deliver the medication in the syringe.

[0033] The damping mechanism includes a friction device for applying friction to the plunger driver. The friction device includes a surface having one or more different coefficients of friction, the surface being positioned so that the surface 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. The surface coefficient can gradually change at one or more points so as to gradually increase the damping on the plunger driver, thereby eliminating any sudden forces that may be applied to the plunger damper. The surface has an area with a greater coefficient of friction at and / or near the first position, thereby damping the initial part of the motion of the plunger driver. The surface has an area with a greater coefficient of friction at and / or near the second position, thereby damping the final part of the motion of the plunger driver.

[0034] The friction device comprises 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.

[0035] The friction device is movable between a position that dampens 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 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, the friction surface may be provided on a door of the device.

[0036] The damping mechanism may include a damping arm pivotally mounted in the housing and positioned so as to contact 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 may further include a reset arm pivotally mounted in the housing and positioned so as to contact the plunger driver when the plunger driver moves from the second position to the first position; the damping arm and the reset arm are coupled such that rotation of one causes rotation of the other. The damping arm and the reset arm are coupled perpendicularly to each other. When rotation of the damping arm is caused by contact with the plunger driver, rotation of the damping arm is damped, and when rotation of the damping arm is caused by rotation of the reset arm, rotation of the damping arm is not damped. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] 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:

[0038] Figure 1a and Figure 1b A perspective view of an automatic injection device is shown.

[0039] Figure 2a A cross section through the automatic injection device is shown.

[0040] Figure 2b An exploded view of the automatic injection device is shown.

[0041] Figure 3 An exemplary damper for an automated injector is shown.

[0042] Figures 4a to 4g Cross-sections of the automatic injection device are shown in various stages of operation.

[0043] Figure 5a to Figure 5b A perspective view of an alternative automatic injection device is shown.

[0044] Figure 5c A perspective view of an alternative automatic injection device undergoing preloading is shown.

[0045] Figure 6a A perspective view of an alternative automatic injection device is shown after preloading.

[0046] Figure 6b A perspective view of an alternative automatic injection device is shown during actuation.

[0047] Figure 7a and Figure 7b A perspective view of another automatic injection device is shown. DETAILED DESCRIPTION

[0048] In general, exemplary methods and apparatus for automatic injection devices are disclosed herein, and in some specific arrangements, the automatic injection devices are safety automatic injection devices. The term "automatic injection device" is used herein and may be considered to encompass both automatic injection devices and safety automatic injection devices, as appropriate. Automatic injection devices may be configured to accommodate and operate with standard syringes (i.e., not safety syringes) and / or safety syringes. A syringe typically includes a barrel that holds a medication. At the front end of the syringe is a needle or a device for holding a needle. A plunger is disposed at the rear end of the syringe. The plunger is typically made of an elastomeric material, and applying pressure on the plunger causes the medication contained within the syringe to be ejected from the syringe through the needle.

[0049] Although the automatic injection device described herein is a reusable automatic injection device, it should be understood that the method described below is also applicable to a single-use automatic injection device in which the plunger drive may not be actuated again. The method described is also applicable to any injection device in which the delivery of the drug is automatic rather than manual.

[0050] In the following embodiments, the terms "forward" and "front" refer to the end of the injection device or a component thereof that faces the patient. In other words, the front end of the injection device is the end that is closest to the injection site during use. Similarly, the term "rear" refers to the end of the injection device assembly or a component thereof that is not located near the patient. In other words, the term "rear" refers to the end that is away from or relatively distant from the injection site during use. Furthermore, the term "longitudinal" is intended to encompass directions along or parallel to the longitudinal axis of the injection device.

[0051] Features of the exemplary arrangements disclosed herein are described as being "coupled" to other features. This term encompasses any coupling that causes the coupled features to move together in any direction, whether on a 1:1 basis or with some gearing. The term "coupled" also encompasses any of a connection between features, abutment of one feature with another, and engagement of one feature with another, and such coupling may be direct or indirect, i.e., with a third feature between the features.

[0052] Figure 1a and Figure 1b An exemplary automatic injection device 100 for housing and operating a syringe 102 is shown. The automatic injection device includes a housing that further includes a plurality of component parts. Figure 1a and Figure 1b In the example of FIG. 1 , the housing includes a main body 104 , a hinged door 106 (referred to herein as a “door”), and in some exemplary arrangements a rear body 108 . Figure 1a The automatic injection device 100 is shown with the door 106 in a closed position. Figure 1b The automatic injection device 100 is shown with the door 106 in an open position. The door 106 is operable between these two positions. As can be seen, when the door 106 is in the open position, the syringe 102 can be housed within the housing, and in this case, specifically within the body 104. The door 106 can include a hinged connection 110 to the body 104.

[0053] Two charging links 112a, 112b connect the door 106 to the body 104. The connection between the charging links 112a, 112b and the body 104 is slidable, and / or the connection between the door 106 and the charging links 112a, 112b is slidable. This allows the door 106 to be opened about the hinged connection 110. Figure 1a and Figure 1b In the example shown, the connection between the loading links 112a, 112b and the main body 104 is slidable.

[0054] The automatic injection device 100 further includes at least one drive spring, and Figure 1a and Figure 1b In the case of the two driving springs 114a, 114b (driving spring 114a is not in Figure 1a and Figure 1b 114b, but located on the opposite side of the automatic injection device 106 in a similar position to the drive spring 114b). The sliding connection of the charge links 112a, 112b to the body 104 is configured to couple with the drive springs 114a, 114b so as to pre-tension the drive springs 114a, 114b by compression thereof when the door 106 is open. It will be apparent to a skilled artisan that other arrangements are possible, such as pre-tensioning the drive springs 114a, 114b when the door 106 is closed.

[0055] The automatic injection device 100 further includes spring guides 116a, 116b (the spring guide 116a is not shown). Figure 1a and Figure 1b , which is located on the opposite side of the automatic injection device 100 in a similar position to the spring guide 116b), Figure 1a and Figure 1b In the example shown, the spring guides 116a, 116b comprise rods. The rods have a cross-shaped cross-section. The rods include reaction surfaces 118a, 118b, against which the rear ends of the drive springs 114a, 114b are positioned. Therefore, expansion of the drive springs 114a, 114b generates a force acting in the forward direction.

[0056] The drive springs 114a, 114b are positioned around the rod so that the rod passes through the hole defined by the drive springs 114a, 114b. In this way, the expansion and compression of the drive springs 114a, 114b follow the path defined by the spring guides 116a, 116b. The skilled person will appreciate that other forms of spring guides may be used.

[0057] The slidable connection of the charging links 112a, 112b may be provided by charging linkages 120a, 120b. The charging linkages 120a, 120b are rotatably connected to the loading links 112a, 112b and are configured to slide along spring guides 116a, 116b. Figure 1a and Figure 1b In the case of , the loading linkage 120a, 120b includes a hole through which the spring guide 116a, 116b (eg, a rod) passes.

[0058] The automatic injection device 100 further comprises two plunger drivers 122a, 122b, but the plunger drivers 122a, 122b are Figure 1a and Figure 1b The plunger drivers 122a, 122b are not easily seen in the drawings, but can be seen well in later figures, which fully describe the operation of the plunger drivers 122a, 122b. Broadly speaking, the plunger drivers 122a, 122b are connected or otherwise coupled to the ends of the drive springs 114a, 114b so that extension of the drive springs 114a, 114b drives the plunger drivers 122a, 122b forward. The plunger drivers 122a, 122b are arranged to contact the plunger of the syringe 102, thereby driving the plunger forward and operating the syringe 102.

[0059] The automatic injection device 100 also includes a shield. Figure 1a and Figure 1b In the exemplary arrangement of FIG. 1 , 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 As shown, when the door 106 is in the open position, the shroud is separated. This allows the syringe 102 to be loaded into the automatic injection device 100 from the top without having to insert the needle end of the syringe 102 through the shroud. The body portion 130 and the door portion 132 also include keying 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, which can then move longitudinally together. A shroud spring biases the shroud in a forward direction.

[0060] The body 104 includes one or more recessed areas that represent a "ghosted" impression of the syringe 102. For example, the body can include a recess 134 for accommodating a handle portion 136 and a finger flange 138 of the syringe 102. Additionally, the body 104 can include a recess 140 for accommodating an extended plunger assembly 142 of the syringe 102. The recess 140 has a length that accounts for tolerances in the plunger position of prefilled syringes.

[0061] Figure 2a and Figure 2b A cross section of the automatic injection device 100 and an exploded view of the automatic injection device 100 are shown respectively. Figure 2a and Figure 2b It also shows that the Figure 1a and Figure 1b Multiple features within the discussed feature.

[0062] Reference Figure 2a and Figure 2b The body 104 includes one or more driver latches 144. For the remainder of this description, reference will be made to features on one side of the longitudinal axis of the automatic injection device 100. 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 forward movement of the plunger driver 122. The driver latch 144 includes a protrusion 146 extending from an elastically deformable arm 148 transversely to the longitudinal axis. The protrusion 146 includes a forward-facing, inclined surface 152 extending laterally from the elastically deformable arm 148 and a rearward-facing latching surface 150. In the rest position of the elastically deformable arm 148, under the influence of the drive spring 114, the protrusion is positioned in the path followed by the plunger driver 122. The plunger driver 122 includes a protrusion 154 extending transversely to the longitudinal axis of the automatic injection device. The protrusion 154 includes a rearward-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 retained by the driver latch 144 .

[0063] The body 104 also includes a shield latch 159, which includes a protrusion 160 that projects transversely of a resiliently deformable prong 162 and transversely to the longitudinal axis of the automatic injection device 100. The protrusion 160 includes a rearwardly facing, angled surface 164 and a forwardly facing latch surface 166. The shield, and in the exemplary arrangement of Figures 1-2, the main body portion 130 of the shield, includes a rearwardly extending latch release arm 168. 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 figures, this is achieved via a driver release surface 170. As described below, the driver release surface 170 rides over the rearwardly facing, angled surface of the driver latch 144 to release the driver latch 144 and permit forward movement of the plunger driver 122.

[0064] The latch release arm 168 also includes a hole or recess 172 in which the protrusion 160 of the shield latch 159 is received prior to operation of the automatic injection device 100. This represents the rest position of the elastically deformable prong 162. In the rest position, the protrusion 160 is out of the path of the plunger driver 122 and is therefore permitted 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 during rearward movement of the shield. 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.

[0065] Figure 3 An exemplary damper 400 is shown mounted on the automatic injection device 100. The damper 400 can be configured to dampen the forward and / or rearward movement of the plunger driver 122. In one example, the damper 400 is configured to dampen at least the initial phase of the forward movement of the plunger driver 122. This initial phase can be up to 15 mm, up to 10 mm, or up to 5 mm. In this manner, tolerances in plunger position are accounted for. The plunger position can affect the overall length of the automatic injection device 100 and / or the amount of travel of the plunger driver 122 before the plunger driver contacts the plunger and the plunger contacts the medicament in the barrel. During this travel, the spring force may cause the plunger to accelerate rapidly, which could result in damage to the syringe or discomfort to the recipient of the injection when the three components come into contact. Damping the forward movement of the plunger driver 122 reduces or overcomes this risk.

[0066] The damper 400 can also be configured to operate over a further forward travel of the plunger driver 122, and in some arrangements, the damper 400 can operate over the entire forward travel of the plunger driver 122. This can reduce the effects of vibration and wear on components of the automatic injection device, thereby extending its life.

[0067] In addition, the damper 400 can dampen the rearward 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.

[0068] exist Figure 3 , an 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 direction or in two directions to dampen the travel of the plunger driver 122.

[0069] Now refer to Figures 4a to 4g Describe the operation of the automatic injection device. Figure 4a In the present embodiment, the hinged door 106 is opened about the hinged connection 110. This causes the charging linkage 120 of the charging rod 112 to slide along the spring guide 116. If the door 106 is opened after operation of the device, the drive spring 114 will extend along the spring guide 116 before opening. Thus, the charging linkage 120 couples (in this case, abuts) to the drive spring 114 during the opening of the door 106. The leverage of the door 106 allows the user to gain a mechanical advantage in pre-stressing the drive spring 114. This can be particularly beneficial when using a high-force spring, such as when the medicament to be delivered by the autoinjector has a high viscosity. In some examples, the viscosity of the medicament may be in the range of 12 centipoise (cP) to 18 cP, 14 cP to 16 cP, or even 15 cP. Furthermore, the medication may need to be delivered through a thin-walled 29-gauge needle, although other gauge needles may also be used. This requires a relatively high spring force, for example 40N to 50N, or even 45N, which may cause the user to find it difficult to perform pre-tightening.

[0070] During the opening of the door 106, the loading linkage 120 compresses the drive spring 114 and moves the plunger driver 122 rearward. The rearwardly facing inclined surface 156 of the plunger driver 122 contacts the forwardly facing inclined surface 152 of the driver latch 144 and displaces the tab 146 laterally to allow the plunger driver 122 to pass. After the plunger driver 122 passes, the tab 146 springs back into the path of the plunger driver 122 under the force of the resilient arm 148. Thus, the plunger driver 122 is latched.

[0071] The door portion 132 moves with the door 106, allowing the syringe 102 to be received laterally into the automatic injection device without passing the needle end through the shield.

[0072] exist Figure 4b In the embodiment of the present invention, the syringe 102 is inserted into the main body 104 using the ghost recesses 134, 140 and the receiving tray 126. The door 106 is then closed around the hinged connection 110. The loading linkage 120 slides forward along the spring guide 116. The plunger driver 122 is retained by the driver latch 144, and the drive spring 114 does not extend along the spring guide 116. Therefore, there is a space on the spring guide 116 into which the drive spring 114 can extend when the automatic injection device 100 is operated. The door portion 132 of the shield is connected to the main body portion 130 of the shield via a keying feature, so that the door portion 132 of the shield and the main body portion 130 of the shield are coupled or connected in the longitudinal direction.

[0073] Figure 4c The cap 124 is shown being removed. The deformable prongs 128 of the receiving tray 126 are snapped onto the RNS of the syringe 102 so that the RNS is also removed. The cap 124 includes a hole through which the RNS falls after the needle is removed.

[0074] As in Figure 4d As can be seen in the figure, the body portion 130 and the door portion 132 of the shield surround the needle and extend beyond the front end of the needle, thereby shielding the needle. The shield is biased in a forward direction under the force of the shield spring. 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 by the hole 172 of the latch release arm 168 and is out of the path of the plunger driver 122.

[0075] exist Figure 4e In one embodiment, the shield is pushed rearward into the automatic injection device 100. This can be accomplished by the user pressing the shield against the injection site. This action exposes the needle, allowing it to enter the injection site. In other arrangements, the syringe 102 can be moved forward within the syringe carrier under the force of a spring. In such an arrangement, the rearward movement of the shield (or, indeed, the pressing of a button) can release the spring, thereby driving the syringe carrier forward for needle insertion.

[0076] The forward facing drive release surface 170 of the latch release arm 168 passes over the rearward facing inclined surface of the protrusion 146 of the driver latch 144. This removes the protrusion 146 from the path of the plunger driver 122 (at Figure 4e Move out laterally. Figure 4eThis action can be seen in circle A of FIG. 1. Furthermore, the rearward movement of the shield causes the shield release surface 174 of the hole 172 in the latch release arm 168 to pass over the rearwardly facing inclined surface 164 of the tab 160 of the sheath latch 159. This displaces the tab 160 laterally into the path of the plunger driver 122 (at Figure 4e (Shift to the right). This action can be seen in circle B.

[0077] The disengagement 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, particularly during the initial phase of the forward stroke. This will be described in more detail below.

[0078] The plunger driver 122 is driven forward until it reaches the shield latch 159, at which point the shield latch 159 is engaged and positioned in the path of the plunger driver 122. Thus, the shield latch 159 stops the forward movement of the plunger driver 122. The shield latch 159 can be positioned so that the plunger driver 122 is stopped at a point in its forward travel at which the full dose of medicament has been delivered from the barrel, or at a later point. The exemplary arrangement shown in the figures is configured for use with a safety syringe, wherein further movement of the plunger after the full dose has been delivered deploys a shield to protect the needle after use of the syringe 102. Thus, stopping the forward movement of the plunger driver 122 prevents the shield from deploying. It should be understood that the shield of a safety syringe can also be deployed under the force of a separate spring, which can be released by a shield release mechanism. Such a mechanism can be released by forward movement of the plunger (or plunger driver 122) after the full dose has been delivered. Such arrangements are encompassed by the embodiments disclosed herein.

[0079] After the entire dose has been delivered, the user lifts the autoinjector away from the injection site. Figure 4gAs shown, the shield is thus urged forward under the force of the shield spring. 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. Consequently, the protrusion 160 enters the aperture 172 under the force of the prong 162. This disengages the shield 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 automatic injection device 100 to move further forward, thereby deploying the shield. The door 106 can now be opened, re-tensioning the drive spring 114 and allowing removal of the shielded safety syringe 102.

[0080] In some arrangements, multiple drive springs 114 may be located on the automatic injection 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 assist in driving the plunger driver 122 forward or to hinder driving the plunger driver 122 forward. Configuration may include removing one or more of the drive springs 114 from the automatic injection device 100. This may be accomplished during assembly of the automatic injection device 100. In other arrangements, a setting on the automatic injection 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 drive springs described above include two extension springs, however, skilled artisans will appreciate that the drive springs may be any other suitable biasing member, including but not limited to extension springs, compression springs, or torsion springs.

[0081] Figures 5a to 6b A perspective view of an alternative automatic injection device for receiving and operating a syringe (not shown) is shown. In these drawings, unless otherwise indicated, similar features operate as described with reference to Figures 1 to 4. Similar features retain the same last two digits of the reference numeral.

[0082] As previously mentioned, the automatic injection device 500 includes a drive spring 514. The drive spring 514 is configured to drive the plunger of a syringe housed within the automatic injection device 500 forward to dispense fluid from the syringe.

[0083] The automatic injection device 500 further includes at least one biaser 509 configured to bias the hinged door 506 toward the preloaded position. As described below, the biaser 509 assists the preload of the drive spring 514 of the automatic injection device 500 by providing an assist force to help the user move the hinged door 506 to its preloaded position in preparation for use.

[0084] The biaser 509 may include one or more springs, which may be tension springs, compression springs, torsion springs, or other types of springs. Figure 5a and Figure 5b In the example of FIG, the biaser 509 includes two torsion springs coupled to the hinged door 506 and the body 504 about the hinged connection 510. During the opening and / or closing movement of the hinged door 506, the relative movement between the hinged door 506 and the body 504 about the hinge 103 causes the torsion springs to twist. Figure 5a and Figure 5b In the example shown, opening the hinged door 506 to load a syringe into the automatic injection device 500 preloads the torsion spring. When the hinged door 506 is in the unpreloaded position, the torsion spring 509 is preloaded. The torsion spring acts on the hinged door 506 to apply a torsional force to bias the hinged door 506 toward its preloaded position (in this case, the closed position).

[0085] exist Figure 5a and Figure 5b In the example shown, opening the hinged door 506 causes the drive spring 514 to translate rearwardly without pre-tensioning the drive spring 514. Thus, the opening movement of the hinged door 506 allows a syringe to be loaded into the automatic injection device 500 prior to pre-tensioning. Prior to closing the hinged door 506, the end of the extension spring of the plunger driver is held in position relative to the body 504. Upon closing the hinged door 506, which is rotatably connected to the loading link 512, the hinged door 506 is pushed forward. In turn, by the slidable connection of the loading link 512 to the body 504 and because the loading link 512 is coupled to the opposite end of the extension spring, the loading link 512 slides along the body 504 and thereby extends the extension spring of the drive spring 514, as will be described later. Figure 5c Displayed in.

[0086] 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 the connection can be rotatable. In some arrangements, the shuttle 511 provides a slidable connection between the loading link 512 and the body 504.

[0087] The shuttle 511 includes a first pre-tensioning portion 515 and a second pre-tensioning portion 517. The drive spring(s) 514 are connected between the first pre-tensioning portion 515 and the second pre-tensioning portion 517. Figure 5bAs 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 toward the hinged connection. Because the drive spring(s) 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 spring 514.

[0088] The body 504 and / or the first pre-tensioning portion 515 may include a latch configured to hold the first pre-tensioning portion 515 in place on the shuttle guide 513 after the hinged door 506 is opened. After the hinged door 506 is opened, the first pre-tensioning portion 515 and the second pre-tensioning portion 517 are separable. Figure 6a As shown, the second preload portion 517 is configured to travel along the shuttle guide 513 when the door 506 is closed, away from the hinged connection 510. Because the drive spring(s) 514 are connected between the first preload portion 515 and the second preload portion 517, when the second preload portion 517 travels forward, the drive spring(s) 514 are preloaded ready to provide a delivery force to the plunger driver and thereby deliver medication from the syringe.

[0089] 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 so that the second pre-tensioning portion 517 is separated from the first pre-tensioning portion 515 and travels along the shuttle guide 513 when the door 506 is closed. This separated state is Figure 6a Shown in.

[0090] Figure 6a A view of the underside of the autoinjector 500 is shown in a preloaded state, with the hinged door 506 closed and the drive spring 514 preloaded. The drive spring 514 is held in its preloaded state by the latch holding the first preload portion 515 in place. Figure 4a In the example shown, the drive spring 514 includes two extension springs, which are fully extended.

[0091] Figure 6b A perspective view of the bottom side of the automatic injection device 500 during actuation is shown. The drive spring 514 is configured to drive the plunger driver forward within the automatic injection device 500 upon actuation to operate the syringe housed therein. Figure 6b In the example of FIG, the extension springs act together to provide the forward force required to inject the medicament in the installed syringe into the patient's body. The plunger driver can be coupled to the drive spring 514 to achieve this purpose.

[0092] The first preload portion 515 is provided with two pinions 530. Those skilled in the art will appreciate that the number of pinions may depend on a variety of factors, and thus any number of pinions may be provided, including one pinion. The pinions are located on a rack (not shown), such as the one previously described. Figure 3 The rack is located on the main body 504, for example, Figure 5a The hole 533 can be seen in the figure.

[0093] The pinion 530 is connected to the drive spring 514 via the first preload portion 515. Figure 6b As shown, when the automatic injection device is activated, the drive spring 514 moves forward in the automatic injection device. When the first preload portion 515 is coupled to the drive spring, the first preload portion 515 also moves along the rack as the drive spring moves. When the first preload 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.

[0094] As will be appreciated by those skilled in the art, there may be a plurality of pistons extending along the entire length of travel of the piston driver. Figure 3 Rack shown or reference Figures 5a to 6b Alternatively, there may be a rack 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.

[0095] The damping of the initial part of the movement of the plunger driver has played a role in reducing the acceleration of the plunger driver, thereby causing the plunger driver to contact the plunger with a force smaller than when the plunger driver is not damped. For example, this helps to use syringes with different plunger positions. For example, when the plunger driver moves at a low speed and the plunger driver is still accelerating, the syringe with the plunger further away from the needle end of the syringe will be contacted. In contrast, when the plunger driver moves at terminal speed, the syringe with the plunger close to the needle will be contacted, and when the speed of the plunger driver is slowed down due to contacting the plunger, a large amount of force needs to be consumed. By using a damper (for example, the damper mentioned 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.

[0096] Damping the final portion of the plunger driver's movement can help reduce the plunger driver's velocity just before the plunger contacts the end of the syringe. This increases the automatic injection device's ability to deliver the full amount of medication contained in the syringe, as the plunger can be driven along the entire length of the syringe while reducing the force exerted by the plunger upon contact with the syringe end. This facilitates the use of medications with varying viscosities, as the plunger will contact the syringe end at a higher velocity when the medication has a lower viscosity than when the medication has a higher viscosity. By reducing the velocity of the plunger upon contact with the syringe end, the force exerted upon the plunger upon contact with the syringe end can be reduced.

[0097] Optionally, the pinion gear may be configured to have damped rotation in one or both directions to dampen the travel of the plunger driver.By reducing the backward movement of the plunger driver, wear on components within the automatic injection device is reduced.

[0098] Although the present invention has been described with reference to a rack and pinion damping mechanism, those skilled in the art will appreciate that any suitable linear damper and / or rotary damper may be used.

[0099] In another example, damping can be provided by providing an area of greater friction to slow the movement of the plunger driver. For example, the friction area can be provided on an area of the shuttle guide 513. The friction area is configured to slow the acceleration of the first preload portion 515 when the automatic 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.

[0100] The friction zone can, for example, be provided on a track so that the plunger driver or a component coupled to the plunger driver can approach continuously. In this case, the zone can be provided with an elastomeric material and an area that is not a friction zone, the area that is not a friction zone being provided with a surface having a friction coefficient lower than that of the friction zone. Alternatively, the track can be such that the plunger driver or a component coupled to the plunger driver contacts the track only 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 required deceleration of acceleration. For example, as previously described, the surface of the track can be provided with an elastomeric material such as rubber.

[0101] When the plunger driver is moved to the preloaded position, the friction surface can be moved away from the plunger driver or a component coupled to the plunger driver so as to reduce the effort required to move the plunger driver to a position where the plunger driver can be actuated again. This can be achieved, for example, by mounting the friction surface on a door of the device or by rotating the friction surface away from the plunger driver or component.

[0102] In yet another example, as shown in FIG. 7 and FIG. Figure 7b As shown, the acceleration of the plunger driver is slowed down by a mechanical device. In these drawings, unless otherwise noted, similar features operate as described with reference to Figures 1 to 6. Similar features retain the same last two digits of the reference numerals.

[0103] Figure 7a The drive spring 714 and plunger driver 722 are shown in a pre-delivery configuration, wherein the drive spring 714 is pre-tensioned. Figure 7b The positions of the drive spring 714 and plunger driver 722 are shown after the automatic injection device has been actuated. Figure 7a and Figure 7b In the configuration shown, damping of the movement of the plunger driver 722 is accomplished using a mechanical member 740 comprising a coupling member 742 and two perpendicular arms. The coupling member connects the mechanical member to the body 704 and provides a pivot point about which the two perpendicular arms can rotate.

[0104] When the automatic injection device is actuated, the plunger driver 722 is Figure 7a The position shown is the same as Figure 7b As the plunger driver moves forward, it contacts one of the two vertical arms that extend out of its path. The plunger driver contact 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 around the coupling member is damped, the acceleration can be further slowed.

[0105] 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 is moved from Figure 7b Move to the position shown Figure 7a During this movement, the plunger driver contacts the other of the arms, causing the mechanical member to rotate about the coupling member back to its original position. This resets the mechanical member and enables it to damp the forward movement of the plunger driver the next time the automatic injection device is actuated. Rotation of the mechanical member can be damped only in the direction of rotation caused by the plunger driver moving forward in the automatic injection device, and not in the direction of rotation caused by the plunger driver moving backward in the automatic injection device. This means that no additional force is required to reset the automatic injection device.

[0106] In the case where the autoinjector is not a reusable autoinjector and therefore does not require the plunger driver to be moved back to Figure 7aIn the case of the position shown, it will be understood that the mechanical member 740 may have only a single arm positioned to dampen the forward movement of the plunger driver.

[0107] Although the present invention has been described with reference to a hinged door, it will be appreciated that other door configurations are possible. For example, the body and door may have a slidable connection.

[0108] A skilled person will be able to devise other components, automatic injection devices, and features thereof 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 may be integrated into the automatic injection devices shown in other figures. It should be understood that the detailed description and specific examples are given by way of illustration only, as various changes and modifications within the spirit and scope of the present disclosure will become apparent to those skilled in the art from 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; d. A damping mechanism configured to dampen movement of the plunger driver in forward or backward motion, the damping mechanism comprising a rack and pinion arrangement, wherein rotation of the pinion is damped in at least one direction.

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

5. The injection device according to claim 4, wherein The damping mechanism includes a rotary damper or a linear damper.

6. The injection device according to claim 1, wherein The pinion is coupled to the plunger driver, and the rack is coupled to the housing.

7. The injection device according to claim 1 or 6, wherein: The rack extends along a portion of the housing at the first location and / or along a portion of the housing near the first location to dampen the initial portion of the movement of the plunger driver.

8. The injection device according to any one of claims 6 to 7, wherein The rack extends along a portion of the housing at the second position and / or along a portion of the housing near the second position to dampen the final portion of the movement of the plunger driver.

9. The injection device according to any one of claims 6 to 8, wherein The rack extends between the first position and the second position so as to dampen the entire range of motion of the plunger driver after actuation.

10. The injection device according to any one of claims 6 to 9, wherein Rotation of the pinion is damped such that when the plunger driver is moving from the first position to the second position, motion of the plunger driver is damped; And when the plunger driver is moving from the second position to the first position, the motion of the plunger driver is not damped.

Images