Auto-injection device with needle protecting cap having outer and inner sleeves

[0001] The present invention relates to an injection device of the type which the syringe contained therein automatically extends, releases its contents and then withdraws. Devices with such a general description are shown in documents US 5 599 309; WO 95/35126, WO 05/070481 and EP-A-0 516 473 and usually use a drive spring and some kind of release mechanism that releases the syringe from the influence of the drive spring when it can be assumed that its contents have been removed to allow retraction her through the return spring.

[0002] Generally, the return spring is relatively weak, because its restoring force must be overcome by the drive spring, even when the drive spring acts on the various components of the injection device and the syringe during the injection cycle. This can cause problems when the injection device is used with sealed subcutaneous syringes, which usually have a hermetically sealed lid or "cover" that covers the hypodermic needle and maintains the sterility of the contents of the syringe.

it is necessary to maintain the sterility of the syringe until it is administered to the patient, which means in the case of devices made for single use, and many are done in such a way that the cover must be removed, with the syringe inside the injection device.

Naturally content [0003] The action required to remove the cover from the syringe usually involves simply pulling the cover off the syringe, which requires the use of force exceeding 20 N. This is much more than the force restoring the balance of the return spring, so the syringe will be pulled out of the injection device. when the cover is removed and when the cover is removed, the syringe snaps into place again. This is not the best way to handle the syringe. A shock could damage it, the needle could be damaged, and problems could arise with the syringe to re-interact with those components of the injection device that are adapted to interact with it. Even in cases where there is no return spring, as in the devices described in US 2005/0203466 and US 6 077 247, in which the syringe is held in place due to friction with the components of the injection device, there is still a problem of re-positioning the syringe relative to these elements components of the injection device that are intended to affect it.

Summary of the Invention [0004] Injection devices according to the present invention are adapted to solve these problems.

[0005] An injection device according to the first aspect of the invention comprises: a housing adapted to accommodate a syringe having an outlet nozzle and having a shield that covers its outlet nozzle so that the syringe is capable of sliding between a retracted position in which the outlet nozzle is located inside the housing and an extended position in which the outlet nozzle protrudes from the housing through the outlet opening, the housing comprising means for moving the syringe from its extended position to the retracted position, capable of releasing the locking mechanism that holds the syringe in its retracted position and a housing closure member that can occupy the first position in which it is located on the housing and prevents the release of the locking mechanism and a second position in which it does not prevent the release of the locking mechanism, while in the first position the housing closing element cooperates with the cover, that the movement of the housing closure member to a second position causes the shield to be removed from the syringe. The device further includes an actuator; a drive which is actuated by the actuator and which, in turn, acts on the syringe to move it from its retracted position to the extended position and release its contents through the discharge nozzle; a release mechanism, releasing the locking mechanism, thereby enabling the syringe to move through the actuator from its retracted position to the extended position, and in which the first position of the housing closure member is the one in which the release mechanism is prevented, and the retraction mechanism actuated when the drive has reached the nominal reversing position to release the syringe from the actuator, after which the displacement means returns the syringe to its retracted position. The locking mechanism is characterized in that it comprises a latching element, which is located inside the housing and is pushed into a position in which it engages with the locking surface. The release mechanism moves it from this position to a position where it no longer engages with the locking surface.

[0006] When the housing closure member is in its first position, it not only is located on the housing and engages with the shield, but also prevents release of the locking mechanism. Thus, the syringe is locked in its retracted position and cannot be moved forward. When the closure member of the housing is moved, it pulls the shield and during this process the locking mechanism still prevents the syringe from moving. Then, the locking mechanism can be released, if desired, allowing the syringe to be moved forward when the device is in use. Thus, the syringe can be moved forward only after the cover has been removed and not during removal.

[0007] Preferably, when the housing closure member is in the first position, it closes the outlet opening of the outlet nozzle. For convenience, the closure element can be removable. In other words, the first position of the housing closure member is the one in which it is placed on the housing, while the second position is the one in which it is not. For example, the housing closure member may be a cap that is placed on the housing by means of a screw connection.

[0008] The release mechanism may be the main element capable of sliding between the locking positions and the first position of the release element, closing the element.

[0009] A particularly effective arrangement is one in which the blocking position of the main element is one in which it projects from the outlet opening, and the release position is one in which it does not protrude from the outlet opening or protrudes to a lesser extent. This means that the main element can be moved from its locking position to its releasing position by contacting the end of the housing injection device is the one in which it covers the main body with the skin at the injection site. In addition, it ensures that the injection device is optimally positioned relative to the injection site before the injection cycle can be started. The main element, in the form of a sleeve, allows contact with the skin of a relatively large surface and allows the syringe nozzle to be extended and retracted in it. In the case of a hypodermic syringe, the sleeve covers the needle, which is beneficial for sensitive patients, especially those who need to administer the drug themselves.

[0010] The above-mentioned main element may comprise a latching hole through which the latch element protrudes before it engages with the locking surface, the main element acting as a cam and the latching element as a pusher so that the movement of the main element from the locking position to the release position disengages the latch member from the locking surface. The latch member may include an inclined surface on which the surface of the main member acts to detach it from the locking surface.

[0011] The injection device may further comprise a trigger capable of moving from a rest position in which it causes the drive to stop in positions corresponding to the withdrawn position of the syringe to an active position in which it no longer stops the drive in this way, allowing it to be pushed out by the element activating and, in turn, ejecting the syringe from the retracted position to the extended position and releasing its contents through the discharge nozzle and the blocking element capable of sliding between the blocking position in which it prevents movement of the trigger from its rest position to its active position and the release position in which it allows movement of the trigger from its position resting position to its active position, after which the trigger is stopped in the active position.

[0012] Such a device provides a visual indication that it is either ready for use or has been used. If ready for use, the trigger is in the rest position. If used, the trigger is in the active position. These positions can be distinguished by the user. In addition, for simplicity, the device includes a mechanism for obtaining such an effect in a security lock mechanism. The trigger may include a blocking element which in the rest position of the trigger engages with the locking surface of the drive and in the active position does not engage.

[0013] The blocking element may comprise a main element, wherein the blocking position of the blocking element is one in which the main element protrudes from the outlet opening and the release position is one in which the main element does not protrude from the outlet opening or protrudes to a lesser extent. This means that the lock member can be moved from the locking position to the release position by contacting the end of the injection device with the skin at the injection site. Nevertheless, this ensures that the injection device is optimally positioned relative to the injection site before the injection cycle can be started. The main sleeve element allows a relatively large skin contact area and allows the syringe nozzle to be extended and retracted in it. In the case of a hypodermic syringe, the sleeve covers the needle, which is beneficial for sensitive patients, especially those who need to administer the drug themselves.

[0014] Locking of the trigger in the rest position can be achieved as follows. The trigger and the lock member include a tab and an opening, the tab being opposite the opening when the lock member is in the release position, but not otherwise. This allows the trigger to move from the rest position to the active position by inserting the tab into the hole. The tab may be on the trigger and the opening is in the lock member.

[0015] Stopping the trigger in the active position can be achieved as follows. The trigger and other device components include a latching projection and a corresponding latching surface on which the latching projection is latched when the trigger is in the active position. The latch projection may be on the trigger. The other component or device is preferably a lock element.

Brief description of the drawings [0016] The invention will now be described by way of example with reference to the accompanying drawings in which:

Figure 1 shows the end of the injection device before attaching the cap to it;

Figure 2 shows it after attaching the cap;

Figure 3 shows a cross-section of the device with the cap attached;

Figure 4 shows a cross-section of the device after removing the cap, and

Figure 5 shows an enlarged fragment of figure 4,

Figure 6 shows schematically in cross-section how an injection device can be further modified; Figure 7 is a partial perspective view of such a modified injection device, and Figure 8 is a cross-sectional view of a preferred injection device.

Detailed description [0017] Fig. 1 shows the end of the injection device housing 112 and the cap 111. Other parts of the device will be described in detail below, but it can be seen that the cap 111 includes a thread 113 that interacts with the corresponding thread 115 at the end of the housing. The end of the housing 112 has an outlet opening 128 in which the protruding end of the sleeve 119 can be seen. The cap 111 has a central guide 121 that fits inside the sleeve 119 when the cap 111 is installed on the housing 112, as can be seen in Fig. 2.

[0018] Injection Fig. 110 shows the device in more detail

The housing 112 contains a traditional type hypodermic syringe 114, including a syringe body 116 ending at one end with a hypodermic needle 118 and a flange 120 at the other end. The traditional syringe plunger, which is normally used to discharge the contents of the syringe 114 manually, has been removed and replaced with drive 134, which ends with plug 122. Plug 122 retains inside the syringe body 116 the drug 124 to be applied. Although the syringe shown is of the subcutaneous syringe type, this is not necessary. Transdermal or ballistic dermal and subcutaneous syringes may also be used in the injection device of the present invention. As shown, the housing includes a return spring 126 that moves the syringe 114 from the extended position in which the needle 118 projects from the hole 128 in the housing 112 to the retracted position in which the outlet nozzle 118 is located inside the housing 112. The return spring 126 acts on the syringe 114 through the syringe carrier 127.

[0019] At the other end of the housing is the actuator, which here is in the form of a compression drive spring 130. The drive from the drive spring 130 is transferred by a multi-part drive to a syringe 114 in order to extend it from the withdrawn position to the extended position and release its contents via needle 118. The drive accomplishes this task by acting directly on medication 124 and syringe 114. Hydrostatic forces acting through medication 124 and, to a lesser extent, static friction between the plug pin 122 and the syringe barrel 116 initially ensure that they are extended together until the return spring 126 reaches the smallest length, or the syringe barrel 116 encounters another obstacle (not shown) ) that will stop his movement.

[0020] The multi-part drive between drive spring 130 and syringe 114 consists of three main components. The drive sleeve 131 takes the drive from the drive spring 130 and transfers it to the flexible latch arms 133 on the first drive element 132. This, in turn, transmits the drive through the flexible latch arms 135 to the second drive element, already mentioned drive element 134.

[0021] The first drive element 132 includes a hollow stem 140, the inner recess of which forms a collection chamber 142 connected to a valve 144 which protrudes from the collection chamber through the end of the stem 140. The second drive element 134 includes a blind hole 146 that is open on the one hand, housing the stem 140 and is closed on the other. As can be seen, the opening 146 and the stem 140 form a fluid reservoir 148 in which the wetting fluid is located.

[0022] A trigger (not shown) is provided which, during operation, serves to separate the drive sleeve 131 from the housing 112, allowing it to slide relative to the housing

112 under the influence of a drive spring 130. The operation of the device is therefore as follows.

[0023] Initially, the drive spring 130 moves the drive sleeve 131, the drive sleeve 131 moves the first drive element 132, and the first drive element 132 moves the second drive element 134, in each case by operating with flexible latching arms 133, 135. The second drive member 134 is moved and, as a result of static friction and hydrostatic forces acting through the drug 124 to be applied, moves the syringe body 116 against the action of the return spring 126. The return spring 126 is compressed and the hypodermic needle 118 appears in the outlet 128 enclosures 112. This continues until the return spring 126 reaches the shortest length, or the syringe body 116 encounters another obstacle (not shown) that stops its movement. Because the static friction between the second element and the syringe body 116 and the driving force 134 hydrostatic, by medicine

124, operating to be applied, are not sufficient to resist the full drive force produced by the drive spring 130, at which point the second drive element 134 begins to slide within the syringe body 116 and the drug 124 begins to be released. The dynamic friction between the second drive member 134 and the syringe body 116 and the hydrostatic forces acting through the drug 124 to be applied are, however, sufficient to stop the return spring 126 in its compressed state so that the hypodermic needle 118 remains extended.

[0024] Before the second drive member 134 reaches the end of its path inside the syringe body 116, i.e. before the contents of the syringe are completely released, the flexible latch arms 135 connecting the first and second drive members 132 and 134 reach the stop 137 within the housing 112. The stop 137 moves inward the flexible latch arms 135 from the position shown, to the position where they no longer connect the first drive element 132 to the second drive element 134, supported by the inclined surfaces on the stop 137. When this happens, the first drive element 134 does not it acts longer on the second drive element 134, so that the first drive element 132 can be moved relative to the second drive element 134.

[0025] Because the wetting fluid is contained within the reservoir 148 formed between the end of the first driving element 132 and the blind hole 146 in the second driving element 134, the volume of the reservoir 146 will tend to decrease as the first driving element 132 is moved relative to the second element drive 134, when drive spring 130 acts on the former. When the reservoir 148 is squeezed, the wetting fluid is forced out through the valve 144 into the collection chamber 142. Thus, after releasing the flexible latch arms 135, the force exerted by the drive spring 130 acts on the wetting fluid, causing it to flow through the restrictor formed by the valve 144 and also acts hydrostatically by fluid and friction between the first and second drive members 132 and 134, thus through the second drive member 134. Losses associated with the flow of wetting fluid do not significantly dampen the force on the syringe body. Thus, the return spring 126 remains compressed and the hypodermic needle remains extended.

[0026] After some time, the second drive member 134 finishes its movement within the syringe body 116 and cannot move further. At this point, the contents 114 of the syringe are fully released and the force exerted by the drive spring 130 acts to keep the second drive element 134 in its end position and continue to force the outflow of wetting fluid through the valve 144, so that the first drive element 132 can continue its movement.

[0027] Before the fluid reservoir 148 is emptied, the flexible latch arms 133 connecting the drive sleeve 131 to the first drive element 132 reach another stop 139 within the housing 112. The stop 139 moves the flexible latch arms 133 inward from the position shown to the position in which the arms do not connect the drive sleeve 131 to the first drive element 132, supported by inclined surfaces on the stop 139. When this happens, the drive sleeve 131 stops working on the first drive element 132, allowing it to slide relative to each other. At this point, of course, the syringe 114 is released because the forces generated by the drive spring 130 are no longer transferred to the syringe 114 and the only force acting on the syringe will be the retraction force of the return spring 126. Thus the syringe 114 is now retracted to the retracted position and the injection cycle is completed.

[0028] All this takes place, of course, only when the cap 111 has been removed from the end of the housing 112. As can be seen in Figure 3, the end of the syringe is closed by a cover 123. The central guide 121 of the cap, which fits inside the sleeve 119, when the cap 111 is installed on the housing 112, it is finally hollow and the edge 125 of the hollow end is inclined at the front edge 157 but not at the rear edge. Thus, when the cap 111 is installed, the front edge 157 of the edge 125 is moved after the bead 159 on the cover 123. However, when the cap 111 is removed, the rear edge of the edge 125 is not moved over the bead 159, which means that the cover 123 is Pulled from the syringe 114 when the cap 111 is removed.

[0029] Meanwhile, as can be seen most clearly in Figs. 4 and 5, the syringe carrier 127, against which the syringe 114 cannot slide, is fixed by means of a flexible locking element 161 which is located inside the housing 112 and is pushed into position in which it engages with the locking surface 163 of the syringe carrier 127. Before engaging with the locking surface 163, the latch member 161 also projects through the latch hole 165 in the sleeve 119, the end of which extends from the outlet opening 128. The latch member 161 has an inclined surface 167 on which an edge 171 of the latch hole 165 acts in such a manner what cam acts on the pusher. Thus, the movement of the sleeve 119 towards the housing 112, or, in other words, pressing on the protruding end of the sleeve, causes the edge 171 of the latch opening 165 to contact the inclined surface 167 of the latch element 161, and further pressure causes the latch element 161 to be moved outwards and thus detached from the locking surface 163. The sleeve 119 can be pressed by contacting the end of the injection device with the skin at the injection site. When the latch member 161 has been detached from the locking surface 163, the syringe carrier 127 is released to move, if necessary, under the influence of the actuator and drive.

[0030] Figs. 6 and 7 show how the device can be modified. Although Figs. 6 and 7 differ from Figs. 4 and 5 in some details, the principles discussed herein apply to the device shown in Figs. 4 and 5. As can be seen, the device includes a trigger 300 having a button 302 at one end and a pair of projections 304 that mate with pins (not shown) inside the housing 112, allowing the trigger to rotate about an axis passing through the two projections 304. The main trigger body 300, to which both the button 302 and the projections 304 are attached, forms the locking element 306. In the position shown, the end of the locking element 306, away from the button 302, engages with the end of the drive sleeve 131, which is actuated by the drive spring 130 and which, in turn, operates on the multi-part drive described above. This prevents the drive sleeve 131 from moving under the influence of the drive spring 130. When the button 302 is pressed, the trigger 300 is rotated about the projections 304, which lifts the end of the locking element 306 from its engagement with the drive sleeve 131, so that the drive sleeve 131 can be moved under the influence of the drive spring 130.

[0031] Fig. 7 shows the outlet opening 128 at the end of the housing 112 from which, as can be seen, the end of the sleeve 119 protrudes. As shown in Fig. 6, the sleeve 119 is connected to a button lock 310 which slides with the sleeve 119 The trigger includes a stop pin 312, and the button lock 310 includes a stop hole 314, which, as seen in Figure 6, are not facing each other. They can, however, be positioned opposite each other by the inward movement of the sleeve 119, which causes the corresponding movement of the button lock 310. When the stop pin 312 and the stop hole 314 are not facing each other, the button 302 cannot be pressed; when they are facing each other it can be pressed. The trigger 300 also includes a flexible, hooked locking projection 316, and the button lock 310 includes a latching surface 318 with which the latching projection 316 is engaged when the button is depressed. When the latching projection 316 engages with the latching surface 318, the trigger 300 is permanently connected to the button 302 in the depressed position.

[0032] Thus, the movement of the sleeve 119 toward the housing 112, or, in other words, pressing the protruding end of the sleeve, aligns the stop pin 312 against the stop hole 314, enabling the trigger button 302 to be depressed, after which the button is stopped in the depressed position by the latch projection 316 and a latching surface 318. The sleeve 119 can be pressed by contacting the end of the injection device with the skin at the injection site, which, above all, ensures that it is properly positioned before starting the injection cycle.

[0033] Using the sleeve 119 to both release and lock the trigger 300, and to allow the syringe carrier 127 to slide, along with the shield removing cap 111 that prevents the sleeve 119 from being depressed, results in an integrated injection device with an elegant design.

[0034] Figure 8 shows the preferred injection device 210, to which the improvements described above with reference to Figures 6 and 7 refer. Again, the housing 212 includes a hypodermic syringe 214.

again type, one side closes the traditional ended with the other 222, which removed element,

Syringe 214 is enclosing the syringe body 216, the sides with a hypodermic needle 218, and the flange 220 and rubber plug intended for application of medicine 224 within the syringe body 216. The traditional syringe piston, which could normally be connected to the plug 222 and is used to manually release the contents of the syringe 214, has been provided by the multi-part drive below. Although the syringe presented is of the subcutaneous type again, this is not necessary. As shown, the housing includes a return spring 226 that pushes the syringe 214 from an extended position in which the needle 218 protrudes from the hole 228 in and replaced as described in the housing 212, to a retracted position in which the hypodermic needle 218 fits inside the housing 212. Spring return 226 acts on the syringe 214 through the sleeve 227. [0035] A drive spring 230 is compressed at the other end of the housing. Drive from drive spring 230 is transmitted by a multi-part drive to syringe 214 to slide it out of retracted position and extend its contents through needle 218. The drive accomplishes this task by acting directly on medicine 224 and syringe 214. Hydrostatic forces acting through the medicine 224 and, to a lesser extent, static friction between the pivot 222 and the syringe body 216, initially ensure that they are moved simultaneously until the return spring 226 reaches the minimum length, or the syringe body 216 encounters another obstacle, which will stop his movement.

[0036] The multi-part drive between drive spring 230 and syringe 214 again consists of three main components. The drive sleeve 231 takes the drive from the drive spring 230 and transfers it to the flexible latch arms 233 in the first drive element 232. These elements are shown in detail in "A". The first drive element 232, in turn, transmits the drive through the flexible latch arms 235 to the second drive element 234. These elements are shown in detail in "B". As before, the first drive element 232 includes a hollow shaft 240, the inner cavity of which forms a collection chamber 242. The second drive element 234 includes a blind hole 246 that is open on one side to accommodate the shaft 240 on the other it is closed. As can be seen, the opening 246 and the stem 240 form a fluid reservoir 248 in which wetting fluid is contained. The trigger, as described above with reference to figures 6 and 7, is located in the center of the housing 212.

The trigger, when activated, serves to disengage the drive sleeve 231 from the housing 212 so that it can be moved relative to the housing 212 under the influence of drive spring 230. Operation of the device is as follows.

[0038] Initially, the drive spring 230 moves the drive sleeve 231, the drive sleeve 231 moves the first drive element 232, and the first drive element 232 moves the second drive element 234, in each case by operating with flexible latch arms 233,

235. The second drive element 234 moves static friction and hydrostatic forces, and, as a result of the drug 224 acting through the drug to be applied, moves the body 216 of the return 226 by spring action.

226 is squeezed and the syringe against the return spring. The hypodermic needle 218 appears in the outlet opening 228 of the housing 212. This continues until the return spring 226 reaches the minimum length, or the syringe body 216 encounters another obstacle that stops its movement. Since the static friction between the pivot 222 and the syringe body 216 and hydrostatic forces, acting through the drug 224 to be applied, is not sufficient to resist the full drive force produced by the drive spring 230, at that moment the second drive element 234 begins to slide inside syringe body 216 and medicine 224 is discharged. However, the dynamic friction between the syringe pin 222 and the syringe body 216 and hydrostatic pressure, acting through the drug 224 to be applied, is sufficient to stop the return spring 226 in its compressed state so that the hypodermic needle 218 remains extended. [0039] Before the second drive member 234 reaches the end of its journey within the syringe body 216, so before the contents of the syringe are fully released, the flexible latch arms 235 connecting the first and second drive members 232 and 234 reach the stop 237. The stop 237 is formed by a component 262 that is initially free to move relative to all other components, but which is trapped between the syringe flange 220 and the additional flexible arms 247 on the second drive member 234. These additional flexible arms 247 cover the flexible arms 235 on first drive element 232, by means of which the drive is transferred to the second drive element 234. Figure 3 illustrates the injection device 210 in a position in which additional flexible arms 247 are just in contact with the stop 237 in component 262.

[0040] The stop 237 moves the additional flexible arms 247 inward, supported by the inclined surfaces on both components and the additional flexible arms 247, in turn, move the flexible arms 235 with which the drive is transferred from the first drive element 232 to the second drive element 234, inwards, from the position shown, to the position in which they no longer connect the first and second driving means with each other. When this happens, the first drive element 232 will no longer act on the second drive element 234, allowing the first drive element 232 to move relative to the second drive element 234.

[0041] Because the wetting fluid is contained in the reservoir 248 formed between the end of the first driving element 232 and the blind hole 246 in the second driving element 234, the volume of the reservoir 248 will decrease when the first driving element 232 is moved relative to the second driving element 234 when a drive spring 230 acts on the first driving element. When the reservoir 248 is squeezed, the wetting fluid is squeezed into the collection chamber 242, Thus, when the flexible latch arms 235 were exerted by the wetting drive spring, causing the collecting 242, and also released, this force

230 acts on the fluid enters the chamber that the fluid acts hydrostatically through the fluid and through friction between the first and second drive members 232 and 234 and thus through the second drive member 234. Losses associated with the flow of wetting fluid do not significantly suppress the force acting on the syringe body. Thus, return spring 226 remains compressed and the hypodermic syringe remains extended.

[0042] After some time, the second drive member 234 completes its journey within the syringe body 216 and cannot be moved further. At this point, the contents of the syringe 214 are fully released and the force exerted by the drive spring 230 acts to stop the second drive element 234 in its end position and still cause the wetting fluid to flow into the collection chamber 142, so that the first drive element 232 can continue its movement.

[0043] A flange 270 at the rear of the second drive member 234 typically stops the flexible arms 233 in engagement with the drive sleeve 231. However, before the wetting fluid reservoir is emptied, the flexible latch arms 233 connecting the drive sleeve 231 to the first drive element 232 are moved sufficiently far forward relative to the second drive element 234 so that the flange 270 is positioned opposite the lowering 272 in the flexible arms 233, as a result, it ceases to be effective in retaining the flexible arms 233 in engagement with the drive sleeve 231. Now, the drive sleeve 231 moves the flexible latch arms 233 inward from the position shown to the position where they no longer connect the drive sleeve 231 to the first drive element 232, assisted by the inclined latch surfaces 274 on the flexible arms 233. When this happens, the drive sleeve 231 stops working on the first drive element 232, allowing them to move relative to each other. At this point, of course, the syringe 214 is released because the forces generated by the drive spring 230 are not transferred to the syringe 214 and the only force acting on the syringe is the retraction force of the return spring 226. Thus, the syringe 214 is now retracted to the retracted position and the injection cycle is completed.

Cilag GmbH International Representative:

EP 1 928 523 B1