Automatic injector

[0001] The application concerns and reserves priority over the United States Provisional Patent Application No. 60 / 599,054, filed on August 6, 2004, which is incorporated herein in its entirety, expressly by reference.

Background of the invention

1. Field of the Invention [0002] The present invention relates to an auto-injector or auto-injector for administering a drug to an injection site. The present invention is particularly directed to an auto-injector having a needle guard mechanism to prevent the user from contacting the auto-injector needle after use. The needle guard mechanism is kept closed before starting the auto-injector. After injection, the needle guard mechanism remains in the locked, unfolded position, so that the user cannot access the needle.

[0003] The present invention is also directed to an auto-injector having a supply assembly comprising a sleeve formed as one part. The molded sleeve reduces the total number of components made, while increasing versatility. The molded sleeve can be used in conjunction with cartridges of different sizes, needles of different sizes, and can be used to change the amount of drug administered.

2. Description of Related Solutions [0004] An auto-injector or auto-injector is a device designed to enable the user to administer a metered dose of the drug himself, subcutaneously or intramuscularly, usually in an emergency. Automatic injectors are e.g. used to treat anaphylactic reactions (acute allergic reactions) and to administer antidotes to certain poisons, such as chemicals that affect the nervous system, and to administer various drug compositions, such as diazepam.

[0005] A typical autoinjector has a housing in which a refill is housed. The cartridge has one or more chambers containing the drug compositions or their components and is adapted to be attached to a needle assembly. The cartridge may contain either a pre-mixed liquid drug or a solid drug and a liquid, which components are mixed prior to injection. The housing houses an executive unit with a stored energy source, e.g. a compressed spring. Activation of the executive unit triggers a series of movements, as a result of which the needle extends from the autoinjector, penetrating the user's body so that then the drug composition is forced through the needle into the user's body. After the dose has been delivered to the injection site, the needle remains in the extended position. If the autoinjector is of the type intended to contain a plurality of components of the drug composition in separate, sealed compartments, then a structure can be attached that forces the components to mix when the executive unit is started.

[0006] There is a need for an auto-injector having a cover that provides adequate protection against the needle both before and after use of the auto-injector. U.S. Patent No. 5,295,965 to Wilmot and his team reveals the outer shield against sharp tools intended for the autoinjector after use. The cover element unfolds when the autoinjector is started so that the user cannot see the needle after use. The position of the sheath element relative to the body of the autoinjector is shifted after use, so that the needle cannot be extended again through the hole in the needle shield.

[0007] US Patent No. 6,767,336 to Kaplan discloses a cover for an autoinjector. To reduce the number of components, Kaplan eliminates the exterior of the autoinjector. The cover is attached to the outside of the cartridge's liner. The insert holder has a series of grooves that are sized to accommodate the latch on the cover. When the autoinjector starts, the cartridge inside the cartridge holder releases the pawl from the recess so that the cover can move freely under spring pressure. Because the cover disclosed by Kaplan is located on the outside of the cartridge holder, the user can grip the cover during operation of the autoinjector. In this way, the user can prevent the pawl from being released from the respective grooves, which could prevent the cover from being folded out correctly. This could prevent the cartridge from moving inside the cartridge, which could cause the needle to be delivered before it reaches the injection site. To overcome these drawbacks, greater liberating forces would be needed. When the pawls are released when the cover is unfolded, they are swung outwards. The user may be pinched or otherwise injured during this unfolding.

[0008] If the shield is unfolded prior to administration of the drug, potentially life-threatening situations may occur because the user may not receive the correct dose of the drug. There is a need for a protected cover so that it cannot be moved before using the autoinjector. There is also a need for a cover that does not disturb or adversely affect the auto-injector in case of contact with the user. It is also desirable that the cover be locked in the extended position after using the autoinjector in such a way that the needle is not exposed so that a person cannot accidentally prick themselves with the needle. It is also desirable to have a cover element having locking and unfolding mechanisms that are protected from contact with the user to prevent the cover from being unfolded correctly.

[0009] WO 03/082386 provides an integrated injection device having a syringe with a near end, a far end, a drug delivery needle and a plunger. The injection device also includes a sliding cover on the syringe having a near end, a far end, and which can move by a forced motion between the first and second positions. The injection device has first and second sets of cooperating catches for holding the shield in the first and second positions, respectively. A protruding ratchet extension protrudes from the cover, which can engage through the piston to release the first set of mating latches. The spring element forces the shield to move between the first and second positions relative to the syringe.

[0010] WO 01/37898 discloses a method and device for use in a medical device formed of a medical device and a needle assembly. The needle assembly includes a needle having a pointed tip. The medical device has a connector, such as a Luer connector. The needle assembly is made so that it can be attached to a medical device, and the sharp tip of the needle is automatically shielded after use, preventing accidental contact with a contaminated needle.

[0011] WO 2004/108194 relates to a syringe actuating mechanism. When the syringe actuator shield is pushed down toward the housing, the flexible arm moves inward to release the trigger. This allows the drive element to push the syringe plunger down under spring pressure. When the injection is completed, releasing the cover causes it to return to contact with the corner of the drive element. Then the cam plane pushes the flap laterally, while bending the hinge until the flap enters the empty interior of the drive element, thus allowing the syringe to retract within the housing under the action of the spring.

SUMMARY OF THE INVENTION [0012] The invention is defined by the features of the appended claims. One aspect of the present invention relates to an auto-injector for administering a fixed dose of drug. The medicine can be given by hand or by a caregiver. The autoinjector has a housing. The housing is preferably oval or elliptical in shape, so it is more ergonomic. The oval shape prevents the auto-injector from rolling off the table or flat surface, while providing a larger surface for printing user instructions. The cartridge container is located in the housing. The cartridge enters the cartridge container. The cartridge has at least one opening and houses the medicine. The medicine is closed with a stopper. The cartridge has a needle assembly for administering the drug through it. The cartridge moves forward within the cartridge container from the storage position to the operating position in which the needle extends from the cartridge container so that a dose of drug can be administered. The actuation assembly or drive assembly provides a source of stored energy that can be released to move the piston inside the cartridge for drug delivery through the needle assembly to the user's body and to allow access to the needle after actuation.

[0013] Another aspect of the invention is to provide a needle shield housed in a housing. The needle guard protects the user against unintentional contact with the needle after using the auto-injector, providing protection against injury. Theoretically, the operation of the needle shield is reliable because the shield will not unfold until the needle penetrates the user's body. During operation, the cartridge needle extends through the hole in the needle shield to allow a dose of drug to be delivered. After using the auto-injector, the needle shield is kept in the locked position to prevent the shield from retracting to expose the needle. According to another aspect of the invention, the needle protector has a locked retracted position before operating the autoinjector, thus maintaining a compact configuration of the device prior to use. According to another aspect of the invention, the actuating forces associated with the autoinjector do not affect the needle shield.

[0014] According to another aspect of the present invention, the autoinjector has a first blocking assembly that holds the shield in the first locked position. The first locking assembly may be located on the cartridge container. The first blocking assembly may include at least one locking tooth pivotally connected to the cartridge container or needle shield. Each locking tooth releasably engages the needle shield and has a locking surface constructed and adapted to contact the surface on the needle shield or on the cartridge container. Each locking tooth may be shaped as a separate component that is connected to the container or to the sheath. It is contemplated that the locking teeth may be formed as integral parts of the needle shield or cartridge. The resilient force of the locking tooth presses the locking surface against the needle shield. The elastic force can be provided by the elastic part of the locking tooth. The elastic force may also be provided by a separate spring assembly pressing the locking surface against the needle shield. Each locking tooth is preferably pivotally connected to the cartridge container. Each locking tooth rotates in response to the movement of the cartridge within the cartridge container. It is also contemplated that the locking tooth may rotate in response to the movement of the sleeve or drive assembly. Typically, the locking surface rotates, losing contact with the needle protector when the locking tooth rotates in response to movement of the cartridge. The elastic force and the force with which the locking tooth acts on the cartridge are controlled so that these forces negatively or minimally interfere with the movement of the cartridge during the injection procedure to avoid premature rupture of the membrane inside the cartridge and premature drug administration.

[0015] The needle cover is pressed by a spring such that the shield is pressed outwardly from the housing to cover the exposed needle after releasing the first locking assembly. According to another aspect of the present invention, the autoinjector has a second locking assembly that holds the needle shield in a second locked position. The second locking assembly may be located on the cartridge container, outer body or shielding element. The second locking assembly may include at least one locking arm or tab, preferably connected to the cartridge container. Each locking arm is spaced from the cartridge container such that the locking arm can be temporarily pressed against the cartridge container as the needle protector moves from the first locked position to the second locked position. Each locking arm has a locking surface for engaging the needle shield when the needle shield is in the locked extended position. Each locking arm has a thick compression part and a thin compression part, the thick compression part being curved outwards and the thin compression part being curved inwards. This design stops the locking arm in its normal uncompressed condition to reduce pressure on the cartridge container. It also allows the cover element to unfold smoothly. In addition, such a system ensures that the thick compression part will bend to a stable state. This creates a strong lock to prevent the cover element from moving backwards to the retracted position. The inwardly curved shape of the thin compression part allows the thick part to bend in a controlled manner to a stable state. In addition, the outwardly bent shape of the thick compression portion ensures reliable locking of the guard in the extended position. If the thin compression part breaks, the thick compression part will still be coupled to the shield element to keep it in the extended locked position.

[0016] The refill container may further have at least a projection extending from the outside. Each projection is constructed and adapted to engage the edge of the opening in the needle shield to limit the stroke of the needle shield relative to the cartridge container when the needle shield is in the extended position. When the projection on the cartridge container engages with the edge of the opening, the stroke of the needle shield outside is limited. The second locking assembly limits the stroke of the needle shield to the inside. The needle cover and cartridge container have holes formed therein. When the holes are ripped together before starting the autoinjector, the user can see the contents of the cartridge through the housing and the holes. The housing may be transparent or opaque. When the housing is opaque, it may have an opening that can be aligned with the holes in the needle shield and cartridge container so that the color of the drug can be checked to determine if the drug is injectable or not. If the medicine has changed color, the user will know that the medicine should not be given. When the holes are not ripped after using the autoinjector, the user can no longer see the contents of the cartridge through the holes, which provides the user with visual information that the autoinjector has been used.

[0017] Another aspect of the present invention is the design and arrangement of an actuation assembly or drive assembly that is mounted in the housing at an open end. The release pin or safety pin is removable attached to the actuation assembly to prevent the injector from unintentionally starting when the release pin is in place. The pin or stem on the release pin goes into the hole in the actuation assembly to prevent the auto-injector from starting. This opening in the drive assembly is distanced from the open end of the housing, so that the opening is less visible to the user before administration of the drug. This arrangement was introduced to prevent the user from pointing the wrong end of the autoinjector towards the injection surface on the user's body. The drive assembly is retracted or spaced from the end of the housing, which is an indication to the user that pressing the drive assembly will not activate the autoinjector. The retracted drive assembly is used to hide the pin hole in the drive assembly when the user views the instructions on the outer body so that the user does not confuse the release pin hole with the hole through which the needle passes for drug delivery. The release pin has at least one projection extending therefrom. The tongue fits into the complementary recess formed in the actuation assembly to prevent the unintentional removal of the release pin. The tabs also prevent rotation of the release pin, so that the user can easily recognize that the release pin must be pulled to remove it. [0018] The actuating assembly has an outer body that is configured to engage with a release pin. The outer body is constructed to connect with the housing. The inner body is operatively connected to the outer body. At least one retaining tab on the inner body secures the inner body to the outer body. The inner body may perform limited movement relative to the outer body. The sleeve is operatively connected to the inner body. The energy source is operatively connected to the inner body and sleeve. Unlike conventional sleeves, the sleeve in the present invention is formed as a single part. There are no spacers or other parts between the bushing and the piston in the cartridge. This system simplifies the construction. Bushes of different sizes can be produced and mounted in an actuation assembly, so all you need to do is change the bushing when using different sizes of cartridges or give a different dose. BRIEF DESCRIPTION OF THE DRAWINGS [0019] Understanding of the various embodiments of the invention can be achieved by the following figures, whose similar elements in the various figures bear the same reference numerals in which the figures:

Figure 1 is a cross-sectional view of the auto-injector according to an embodiment of the present invention;

Figure 2 is a cross-sectional view of the auto-injector of Figure 1 in a non-actuated state having a release pin in place;

Figure 3 is a schematic side view of the autoinjector in the non-actuated state of Figure 2;

Figure 4 is a cross-sectional view of the auto-injector of Figure 1 having the release pin removed in preparation for actuation;

Figure 5 is a cross-sectional view of the auto-injector of Figure 1 in which the needle shield spring is in a compressed state;

Figure 6 is a schematic side view of the auto-injector of figure 5; Figure 7 is a cross-sectional view of the auto-injector in the actuated state with the needle in the drug delivery position;

Figure 8 is a schematic side view of the auto-injector of Figure 7; Figure 9 is a cross-sectional view of the auto-injector after administration of the drug, the needle shield being in an extended, secured condition;

Figure 10 is an enlarged view of the locking wings of the cartridge container when the needle shield is in an extended, secured condition as shown in figures 9 and 11;

Figure 11 is a schematic side view of the auto-injector of figure 9;

Figure 12 is a schematic view from the left of the front of the auto-injector of Figure 1 with the outer body removed, the needle shield being in a retracted position before operating the auto-injector;

Figure 13 is an enlarged fragment of Figure 12 showing the location of the locking flaps of the cartridge container and the locking teeth;

Figure 14 is a schematic view from left of the front of the auto-injector of Figure 1 with the outer body removed when the needle shield is in the extended, secured position after use of the auto-injector;

Figure 15 is an enlarged fragment of Figure 14 showing the location of the locking flaps of the cartridge container and locking teeth;

Figure 16 is an enlarged cross-sectional view of the position of the locking teeth when the needle guard is in the extended, secured position;

Figure 17 is a perspective view from the left of the rear of the outer body of the drive train for the self-injector drive assembly of the present invention;

Figure 18 is a side perspective view of the sleeve for the auto-injector drive assembly of the present invention;

Figure 19 is a perspective view from the right of the front of the inner body of the drive assembly for the autoinjector drive assembly of the present invention;

Figure 20 is a side perspective view of the spring assembly for a self-injector drive assembly in accordance with the present invention;

Figure 21 is a perspective view from the left of the bottom of the release pin of an autoinjector according to the present invention;

Figure 22 is a perspective view from below of the right side of the auto-injector drive assembly when assembled;

Figure 23 is a cross-sectional view of the drive assembly of Figure 22;

Figure 24 is a perspective view from the left of the top of the drive assembly of Figure 22 with the upper release pin removed and the circumferential rib of the outer body of the drive assembly;

Figure 25 is a perspective view from the left of the top of the drive assembly of Figure 22;

Figure 26 is a perspective view from the left of the top of the drive assembly positioned in the outer body, with the locking pin removed;

Figure 27 is a perspective view from the left of the outer body of the drive assembly,

Figure 28 is a partial cross-sectional perspective view of the interior of the outer body of the drive assembly;

Figure 29 is a partial cross-sectional perspective view of the interior of the internal body of the drive assembly;

Figure 30 is a side perspective view of the inner body of the drive assembly;

Figure 31 is a perspective view from below of the inner body of the drive assembly;

Figure 32 is a side view of the release pin;

Figure 33 is a different side view of the release pin of Figure 32, rotated 90 ° about an axis;

Figure 34 is a perspective view from below of the safety pin of Figure 32;

Figure 35 a side view of the drive assembly bushing;

Figure 36 is a side view of the sleeve of Figure 35 rotated 90 ° about an axis;

Figure 37 is an enlarged view of the sleeve showing the stabilizing arc;

Figure 38 is a perspective view of the needle shield disposed within the outer body of the autoinjector;

Figure 39 is a cross-sectional view of the cartridge container and needle shield positioned in the outer body, with the drive assembly removed, prior to final assembly of the autoinjector;

Figure 40 is a cross-sectional view of the cartridge container and needle shield disposed in the outer body of Figure 39 rotated 90 ° about the axis, with the drive assembly removed, prior to final assembly of the autoinjector;

Figure 41 is a perspective view from the left of the front of a container of an autoinjector cartridge;

Figure 42 is a perspective view of the needle shield spring;

Figure 43 is a perspective view from the left of the front of a needle pen of a self-injector;

Figure 44 is a perspective view from the left of the front of the outer body of the autoinjector;

Figure 45 is a different perspective view from the left of the outer body of Figure 44;

Figure 46 is a perspective view with a partial cross section of the interior of the outer body;

Figure 47 is a side view of the outer body;

Figure 48 is a different side view of the outer body of Figure 47 rotated 90 ° about an axis;

Figure 49 is a perspective view from the right of the rear of the back of the autoinjector cartridge;

Figure 50 a side view of the cartridge container;

Figure 51 is a different side view of the container of the cartridge of Figure 51 rotated 90 ° about an axis;

Figure 52 is an enlarged side view of the cartridge container shown in Figure 51, wherein the dashed lines represent the deflection path of the locking wings;

Figure 53 is a perspective view from the right of the rear of the auto-injector needle cover;

Figure 54 is a side view of the needle shield of Figure 53;

Figure 55 is a perspective view of the needle shield spring;

Figure 56 is a perspective view from above of the right side of the locking tooth of the autoinjector according to the present invention;

Figure 57 is a perspective view from the left from below of the locking tooth of Figure 55;

Figure 58 is a side perspective view of the locking tooth; and Figure 59 is a top view of the locking tooth.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT [0020] It will be appreciated that some of the components described herein are classically known in broader aspects as described in US Patent No. 4,031,893 ("893 patent") incorporated herein in its entirety by reference, and therefore not described here as necessary. It will also be appreciated that known modifications or changes introduced to the '893 patent may be as applicable to the auto-injector of the present invention as will be described below. These modifications or changes include the embodiments described in US Patent Nos. 4,226,235; 4,329,988; 4,394,863; 4,723,937; and subsequent US tax numbers 09 / 985.466; 10 / 285,692, each of which is incorporated by reference in its entirety for full disclosure.

[0021] The auto-injector 100 according to the present invention will now be described in more detail with reference to Figs. 1-59. The autoinjector 100 has an outer body 110, a release pin 120, a drive assembly 130, a cartridge container 140, a needle shield 150, and a drug holding cartridge 160. This dose can be stored in liquid or solid form or as a combination of liquid and solid which is mixed prior to injection.

[0022] The autoinjector 100 has an outer body 110 shown in Figures 38 and 4448. The outer body 110 has a generally oval or elliptical shape which, compared to the cylindrical body, has more ergonomic shapes to allow easier gripping and use by the user or caregiver. The generally oval shape of the outer body 110 prevents the injector 100 from unintentionally rolling or sliding off the flat surface. In addition, the oval shape provides a larger printable surface for marking the auto-injector with 100 instructions. The outer body 110 is preferably made of synthetic material so that it can be molded more easily. The outer body 110 can be transparent, so that the inner components can be easily seen through the outer body 110. Due to this design, the user can view the contents of the cartridge 160 through the windows 141a and 141b in the cartridge container 140 and the needle shield 150 at predetermined times. It is also contemplated that the outer body 110 may be opaque so that the inner parts will not be visible through the outer body 110. It is also contemplated that the outer body 110 may have a window or windows that allow viewing of the components inside the outer body 110. The outer body 110 has an opening 111 formed at one end that has dimensions selected to accommodate the release pin 120. When in place, the release pin 120 prevents unintentional use or activation of the autoinjector 100. The release pin 120 is shown in Figs. 32-34. It is contemplated that the operating instructions can be printed directly on the outer body 110. It is also contemplated that the label can be attached to the outer body 110, which can increase the rigidity of the outer body 110. When the outer body 110 has one or more holes, the attachment of the label increases the strength of the outer body 110, which makes additional structural reinforcement unnecessary.

[0023] The opening 111 has side indentations 111a and 111b that run down along the opposite sides of the outer body 110 shown in Figures 45, 46 and 48. Although two indentations are shown, it is contemplated that a single indentation or more than two can be used recess. The number of wells will correspond to the number of protrusions. The recesses 111a and 111b have dimensions chosen such that they can accommodate projecting projections 121a and 121b on the release pin 120. The tabs 121a and 121b prevent the release pin 120 from rotating, so the user can easily recognize that the release pin 120 should be pulled out instead of rotating to allow the release pin 120 to be removed to actuate the autoinjector 100. The releases 121a and 121b mainly enter the locking recesses 235 located at opposite sides of the drive assembly 130, described in more detail below. The recesses 111a and 111b allow access to the projections 121 in the recesses 235. The projections 121a and 121b engage with the drive unit 130 to prevent inadvertent removal. To release pin 120, the user squeezes or clamps tabs 121 to extend the edges of tabs 121 from recesses 235, so pin 120 can then be pulled out / removed from drive assembly 130. As shown, tabs 121 have a curvature that forms a bevelled edge that mates with along the edges of the cavity 235. The shapes of the projections 121 and the depressions 235 are completely complementary, which creates a holding force due to friction or compression between the pin 120 and the drive unit 130. The release pin 120 also has downwardly projecting ribs 122a and 122b that are adapted to abut on the upper surface of the drive unit 130. Ribs 122a and 122b increase the stability and rigidity of the release pin 120. The use of additional ribs is considered. The release pin 120 has an outwardly facing flat end 123 having a circumferential projection 124. The circumferential projection 124 allows the user to grip the release pin 120. The projection 124 is sized to rest on the face of the outer body 110 at the opening 111. The release pin 120 has a downwardly projecting pin 125 that engages with the bushing 430 of the drive unit 130. When it is secured in place (i.e. before removing the release pin 120 and before starting the autoinjector 100), the pin 125 prevents the end of the sleeve 430 from being squeezed, which prevents the autoinjector 100 from starting. The end 123 has shapes that match the oval / elliptical shape of the outer body 110.

[0024] As shown in figure 46, the inner surface of the outer body 110 is shaped to receive the drive assembly 130, the cartridge container 140 and the cover

150 needles. Unlike many known needle guards, the needle shield 150 is positioned between the container 140 and the outer body 110, so that the user does not touch the shield 150 during operation, which could interfere with the protrusion of the shield or cause premature rupture of the membrane inside the cartridge. In addition, the mechanisms for locking and extending the sheath are located inside the outer body 110, and thus are protected from being broken or penetrated by dirt. The outer body 110 has a resistance cup 112 holding on to the refill container formed on the inner surface at the end of the outer body 110 at the opening 111. The projection 142 of the refill container 140 rests against the resistance step 112 to limit the downward movement of the refill container 140 inside the outer body 110 after assembly of the autoinjector 100, so the container cannot slide out of the opening 114. A series of holes 113a, 113b and 113c holding the drive assembly are formed on at least one side of the outer body 110. The projections or teeth 238 on the drive assembly 130 snap into the holes 113. This snap fitting prevents removal of the drive assembly 130 from the outer body 110 when mounted in the outer body body 110. The outer body 230 of the drive assembly cannot move relative to the outer body 110. The projection 142 of the cartridge container 140 is located between the stop stage 112 and the drive assembly 130.

[0025] The opening 114 is formed in the outer body 110 at an end opposite the opening 111. The opening 114 is shaped so that a portion of the cartridge container 140, a portion of the needle shield 150 can protrude therefrom. The stage 112 limits the stroke of the container 140 through the opening 114. The end of the outer body 110 is intended to be in contact with the injection surface of the wearer's body so that the end portion of the cover 100 contacts the injection surface.

[0026] The drive assembly 130 will now be described in more detail with reference to Figs. 17-20, 22-31 and 35-37. The drive unit 130 has an external drive unit body 230, an internal drive unit body 330, a bushing 430, and a drive unit spring assembly 530. The actuating force required to release the energy stored in the power unit is between 4 and 8 pounds. The actuating force is the force necessary to release the sleeve 430 from the inner body 330 when the autoinjector 100 presses against the injection surface. The injection force generated by the spring assembly 530 is about 30 pounds. The injection force must be sufficient to move the cartridge 160 inside the cartridge container 140 and push the needle in so that it pierces the sheath to allow the user to inject the drug. The outer drive body 230 is typically a cylindrical longitudinal hollow body 231. A series of outer, circumferential ribs 232a, 232b and 232c protrude outwardly from the outer surface of the hollow body 231. Although these ribs 232 are shown, additional ribs may be considered. Ribs 232 are designed to prevent the outer body 110 of the autoinjector 100 from twisting. A series of longitudinal ribs 233a, 233b are spaced around the outer surface of the hollow body 231. The ribs 233 cooperate with the ribs 232 to further strengthen the autoinjector 100 and prevent deformation of the outer body 110 when squeezed by the user.

[0027] One of the circumferential ribs 232a forms the upper face 237 of the outer body 230 of the drive assembly. An aperture 234 is provided in the front surface, the dimensions of which allow the downwardly projecting pin 125 of the release pin 120 to be received. The cutouts 235a and 235b are formed on opposite sides of the hollow body 231 at the upper surface. The recesses 235a and 235b are formed by walls 236a and 236b that protrude outwardly from the hollow body 231 and up from the upper face surface 237 of the circumferential rib 232a. The recesses 235a and 235b are in tune with the side recesses 111a and 111b of the outer body 110 such that when the release pin 120 is attached to the autoinjector 100, the tabs 121a and 121b enter into both the recesses 235a and 235b. The recesses 235a and 235b have dimensions selected to act on the tabs 121a and 121b to clamp the release pin 120 in place and prevent unintentional removal.

[0028] As shown in Figs. 17, 26 and 27, the walls 236a and 236b protrude upward from the face surface 237 of the circumferential rib 232a. In such an arrangement, the front surface 237 is spaced or recessed under the front surface of the outer body 110, as shown in Figure 26, forming a cavity 115. The cavity 115 reduces and / or eliminates the visual impression of the button. Therefore, the user will not be encouraged to press the front face 237 to administer the drug. In addition, this provides a visual indication to the user that the recess 115 is located at the non-working end of the autoinjector 100, so the user is encouraged to position the cover 150 in contact with the injection surface, not the opposite end of the autoinjector. The recess 115 also serves to move the opening 234 away from the end of the autoinjector 100 so as not to emphasize the presence of the opening 234 so that it is hidden when the user reads the label on the outer body 110. Therefore, nothing encourages the user to position the opening 234 near the injection site. This system is only one preventive measure to prevent misuse of the autoinjector 100. The ribs 122a and 122b of the release pin 120 enter into the recess 115.

[0029] A series of protrusions or teeth 238a, 238b, 238c are formed on the outer surface of the hollow body 231. Teeth 238a, 238b, 238c have dimensions sized to snap into the holes 113a, 113b, 113c to secure the drive assembly 130 to the outer body 110. This design allows these components 110 and 130 to be joined together without the use of glue or any other form of connection. A suitable tooth assembly 238 may be on the opposite side of the hollow body 230 to mate with the corresponding holes in the outer body 110.

[0030] The interior of the hollow body 231 has a recess 231a, which is sized to accommodate retaining tab 334 on the inner body 330 of the drive assembly. The recess 231a may be a groove that extends around the inner periphery of the hollow body 231. The recess 231a is located in the hollow body 231 near the end opposite the face 237. As can be seen in Fig. 1 and 28, the sleeve actuating structure 239 protrudes into the hollow body 231 from the inside of the face surface 237. The sleeve actuating structure 239 has a generally cylindrical shape with the slanting surface 239a of the sleeve located at the free end. The actuating surface 239a is positioned such that when the pin 120 is removed and the front end of the pen is pressed against the injection site so that the cartridge container 140 moves back to engage with the internal body 330, it will act backwards on the tips 434, and especially their rearward facing surface 489 (see Fig. 35) to engage with surface 239a to squeeze the tips 434 of the sleeve 430 together to release the spring assembly 530 and thereby release the energy necessary to inject the drug to the user. Ribs 239b may be used to reinforce the sleeve actuating structure 239. The possibility of other means for releasing the sleeve 430 is being considered. A button type actuator may be used, which is described in more detail in US Patent No. 4,031,893, and incorporated herein by reference in its entirety.

[0031] The internal body 330 of the drive assembly is a generally cylindrical hollow internal body 331. The hollow internal body 331 has an opening 332 formed at one end. The aperture 332 has a surface 332a introducing the sleeve assembly that serves to compress part of the sleeve assembly 430 during assembly of the autoinjector 100 so that the assembly can be properly mounted in the internal body 330 of the drive assembly. The hole 332 also has a surface 332b retaining a sleeve located on the opposite edge that supports the opposite tips 434 of the sleeve 430 prior to actuation. The hollow inner body 331 has an opening 333 formed at the opposite end. At a distance from the aperture 333 there are a series of mounting tabs 334 having dimensions sized to snap into the receiving recess 231a. The recess 231 and projections 334 allow limited movement between the inner body 330 of the power package and the outer body 230 of the power unit. The system is also advantageous in terms of mounting the autoinjector 100. Inner body 330 and outer body 230 can be pre-assembled. The recess 231 and the projections 334 keep the inner body 330 and the outer body 230 in the correct orientation for assembly. In addition, this arrangement prevents the inner body 330 and the outer body 230 from being separated prior to final assembly in the autoinjector 100. Other means that allow limited movement between the external power train and the internal power train that attach the components together are also considered. . The projection 335 extends at least partially around the perimeter of the opening 333. The projection 335 has dimensions selected to engage the refill container 140 and the external drive assembly body 230 at certain times during the operation of the autoinjector 100, described in more detail below. There is a gap between the internal drive unit 330 and the cartridge container 140 after assembly and before operating the autoinjector 100 to form a gap, which prevents the constant application of force to the drive unit and spring 530.

[0032] The sleeve 430 enters the hollow interior of the internal body 330 of the drive assembly. The sleeve 430 is preferably formed as a one-piece structure. The sleeve 430 has an elongated body 431 having an opening 432 that forms a pair of side arms 433a and 433b. Each side arm 433a and 433b has a fragment 434a and 434b respectively. One side of each tip 434a and 434b is configured to contact and engage the surface 332b holding the sleeve. The opposite side of each tip 434a and 434b is configured to engage the insertion surface 332a of the sleeve assembly, which allows the side arms 433a and 433b to bend inward to allow the autoinjector 100 to operate. End 435 of the sleeve 430 at the tips 434a and 434b has a hole 435a adapted to receive the pin 125 of the release pin 120. The pin 125 prevents the side arms 433 from bending inwardly towards each other. When in place, the pin 125 prevents the auto-injector 100 from starting. The opening 432 has an arc 432a formed at one end, as shown in Figure 37. The arc 432a helps stabilize the side arms 433 and helps them spring back when the arms are squeezed together. Arc 432a reduces the amount of stress in the sleeve.

[0033] The sleeve 430 is positioned inside the spring assembly 530 of the drive assembly. One end of the spring assembly 530 rests on a collar 436 formed on the sleeve 430. The collar 436 projects out of the elongated body 431. While the collar 436 supports one end of the spring assembly 530, the position of the collar 436 on the body 431 can also be used to determine the dose of drug administered injected to the user. In some applications, it is desirable to control the amount of drug administered through the needle so that some of the drug remains in the cartridge 160. Flange 436 may limit the distance that sleeve 430 can travel in the cartridge 160 that contains the liquid drug. In this way, the amount of drug administered is controlled. In this arrangement, the flange 436 has dimensions so selected that it contacts the end of the insert 160. For larger diameter cartridges and larger drug doses, the possibility of entry of collar 436 into the insert 160 is contemplated. The sleeve 430 further has a projection 437 that receives the piston 438. Piston 438 slides into the insert 160. In other applications it is desirable to administer all of the drug from the container 160. A small residual amount of drug remains in the needle 162 and neck of the cartridge 160 at the needle 162. In these applications, the collar 436 moves within the cartridge 160, so the piston 438 travels the length of the cartridge interior 160 to administer all drug (except for the residual amount described above) through the needle 162. The possibility of using 100 sleeves in this autoinjector is contemplated. 430 different sizes. So you can replace the sleeve 430 depending on the size of the cartridge and the desired dose.

[0034] The sleeve 430 is preferably formed in one piece from a suitable plastic. The one-piece sleeve 430 simplifies manufacturing and reduces costs by reducing the number of components needed to form the sleeve. Many brass components can be used in a classic sleeve. In addition, other autoinjectors require a spacer to be used in conjunction with the 430 sleeve to adapt to different amounts of the drug in different autoinjectors. The sleeve 430 of the present invention eliminates the multi-part structure and also advantageously eliminates the need for a spacer. The length of the sleeve can be selected as a function of the desired dose. This design also eliminates the metal insert typically found in the piston and the firing assembly over the inner body of the drive assembly. It is contemplated that the size and shape of the sleeve 430 itself can be changed to accommodate cartridges of 160 different sizes. When the collar 436 is not in contact with the cartridge 160, the entire content of the cartridge 160 can be given, except for the residual amount remaining in the needle or neck of the cartridge 160. It is contemplated that a needle piston such as disclosed in US Patent No. 5,713,866 to Wilmot, the disclosure of which is specifically incorporated herein by reference, may be used to prevent the accumulation of any residual amounts of drug in the neck of the cartridge 160. The position of the collar 436 can be changed to control the amount of dose injected to the user, so when the collar is positioned such that the sleeve and piston 438 travel a greater distance within the cartridge 160 before the collar 436 contacts the cartridge 160, a larger dose is administered. The length of the sleeve 430 and the diameter of the cartridge 160 can be selected to control the fluid flow rate through the needle 162 of the cartridge 160 so that the desired flow rate is obtained. The auto-injector 100 according to the present invention is configured so that sleeves 430 of different sizes can be used in the same outer body 110 and drive assembly 430.

[0035] The opposite end of the spring assembly 530 rests on the inner surface of the inner body 330 of the drive assembly in contact with the opening 332. [0036] The container 140 will now be described in more detail with reference to Figs. 41 and 49-52. The refill container 140 generally has an elongated, hollow body 141 sized to insert inside the outer body 110. The projection 142 is formed at one end of the elongated body 141. The projection 142 contacts the abutment 112 formed on the inner surface of the outer body 110. The projection 142 limits the downward movement of the cartridge container 140 in the outer body 110 so that it cannot be removed through the opening 114. The projection 142 is formed by the circumferential ribs 142a and 142b which protrude outwardly like ribs 232a, 232b and 232c on the outer body 230 of the drive assembly. Ribs 142a and 142b may also prevent deformation of the outer body 110.

[0037] The elongate hollow body 141 has a hollow interior sized to accommodate the insert 160. The hollow body has an opening 143 such that the insert 160 can be placed in the empty interior and allow the insertion of the sleeve 430 into the insert 160 with the possibility of sliding. The cartridge container 140 and its locking teeth 340 are designed to receive different sizes of cartridges 160 while maintaining full needle shield functionality. As such, a common design of the needle shield assembly (including cartridge container and locking teeth) can be used for different drug volumes and different needle sizes. For longer and larger cartridges, it is desirable to provide additional support to prevent axial and radial movement that could damage or break the cartridge 160. A pair of projections 600 are formed on the hollow body 141 to exert a compressive force on the insert 160 to hold and position the insert 160 in position to prevent such radial and axial movement.

The projections 600 generate friction to prevent movement of the cartridge 160 in the hollow body 141 during impact loading, to prevent the cartridge carrier 140 from pushing or moving forward before the drug delivery cycle. Typically, the smaller cartridges do not touch the tabs 600. A sleeve 430 as well as a needle and needle guard provide sufficient support for the cartridge. The end of the hollow body 141 has a conical structure with an aperture 144 that allows a needle 162 and a protective sheath 165 of the insert 160 to pass through. A series of ribs 145 are formed on the outer surface of the hollow body 141 at the conical end. Ribs 145 help stabilize the spring 153 of the needle shield 150. Ribs 145 also serve as guides to aid in the installation of the 100 injector.

[0038] The elongate hollow body 141 has at least one viewing window 141a and 141b. The sight glasses 141a and 141b allow the user to view the contents of the cartridge 160 before operating the autoinjector 100 to make sure that the drug has not been contaminated or is not expired.

[0039] A pair of locking arms or wings 240 protrude from the projection 142 connecting to the central portion of the hollow body 141 as shown in Figure 52, each locking wing 240 having a thickened compression portion 241 having a generally curved shape as shown in Figure 52. The thickened compression part 241 is curved so that when the compressive load acts on the locking wing 240 (e.g. when the user attempts to push the needle shield 150 back into the outer body 110 after using the autoinjector 100), the thickened compression portion 241 bends as indicated by the dashed lines in Figure 52. Thanks to this design, the locking wings 240 are supported by the body 141 of the cartridge container 140, which increases the compressive strength of the locking wings 240. Although not preferred, the use of a single locking wing 240 is contemplated.

[0040] The thinner compression part 242 projects from the free end of the compression part 241 and is connected to the body 141 of the cartridge container 140. The locking surface 243 is formed at the intersection of the compression parts 241 and 242. The locking surface 243 cooperates with the surface on the sheath 150 to limit movement within the sheath 150 after using the autoinjector 100 as shown in figures 9 and 10. The thinner compression part 242 provides a spring force to keep the thicker compression part 241 pressed outwards. The thinner compression part 242 also provides tensile strength under extreme loads and prevents the compression part 241 from collapsing sideways because the thinner compression part 242 remains held in the guide groove in the needle shield 150 after the shield member 150 has moved to the extended position. The curved shape of the compression part 242 allows the compression part 242 to bend inward, as indicated by the dashed lines in Figure 52. This prevents the entire wing 240 from forming a rigid arch. In this way, the thicker compression part 241 can be bent inward towards the body 141 not causing excessive compressive loads along the wing 240. The possibility of positioning the locking arm 240 on the outer body 110 is considered.

[0041] As shown in figures 39, 41, 49, 50 and 52, the elongate body 141 of the refill container 140 has a recess 244 located between the thinner compression part 242. If the locking arms 240 are located on the outer body 110, the recess 244 may be formed in outer body 110. Alternatively, an opening may be formed in outer body 110. This recess 244 increases the distance by which the thinner compression part 242 moves towards the body 141, which increases the elastic force transmitted to the thicker compression part 241 to keep the compression part 241 in the outwardly pressed position. Locking wings 240 are normally kept under tension. The locking wings 240 are momentarily squeezed as the needle shield 150 passes over them. The locking wings 240 bounce outwardly so that the locking surface 243 engages with the cover 150 to prevent the cover from being depressed.

150 needles backwards as shown in figure 10.

[0042] The elongate slot 146 is formed on each side of the elongated body 141. The slot 146 extends from the ends of the compression portion 242, as shown in Figures 49 and 51. Each slot 146 has dimensions to receive a locking tooth 340. As shown in Figures 1, 2, 4, 5, 7, 9, 16, 39 and 41, the locking teeth 340 are locked on opposite sides of the cartridge container 140. The locking teeth 340 are intended to prevent the needle shield 150 from sliding out earlier than after use of the autoinjector 100. There are a pair of locking teeth 340. Although not preferred, the possibility of using a single locking tooth 340 is considered.

[0043] Each locking tooth 340 can rotate about the support axle 341 in the axle slot 147. A number of aperture slots can be used such that tooth position 340 can be adjusted. As shown in Figs. 56-59, each locking tooth 340 has a projection 342 having a bearing surface 342a. The projection 342 is positioned in the slot 146 so that it enters the hollow body 141 and can contact the insert 160. When the insert 160 slides forward in the body 141 during operation of the autoinjector 100, the contact between the insert 160 and the bearing surface 342a causes the locking tooth 340 to rotate about the axle 341. When the bearing surface 342a contacts the insert 160, the locking teeth 340 have minimal or negligible impact on the movement of the cartridge 160 in the container 140 during the injection procedure. The low or minimal force with which the locking teeth act on the cartridge is beneficial because it does not create a pressure inside the cartridge that could prematurely tear the membrane before the needle is fully extended. Furthermore, the locking tooth 340 does not interfere with the movement of the insert 160 in the container 140, or does so negligibly. The projection 342 projects on one side of the axle 341. The resilient end portion 343 projects on the opposite side of the axle 341. The resilient end portion 343 is positioned in the slot 146 and is intended to slide along the cartridge container 140. The resilient end portion 343 serves to press the locking tooth 340 into a locked position such that the needle shield 150 is held or locked in a retracted position prior to use of the autoinjector 100. It is contemplated that the elastic end portion 343 may be replaced by a spring assembly. The support surface 344 is at one end of the end portion 343 to allow the elastic end portion 343 to gently slide along the cartridge container 140 within the slot 146. The support surface 344 and the central body 345 provide a flat area for the ejector pin.

[0044] Under the resilient end portion 343, a V-shaped notch 347 is formed. The notch 347 has on one side a locking surface 347a that holds the needle shield 150 before actuating the autoinjector 100. The second surface 347b limits the tooth stroke 340 within the cartridge container 140 to limit his turn. The notch 347 is shaped as a part of the projection 348 that extends on both sides of the elastic end portion 343. Blocking teeth 340 increase the flexibility of using the autoinjector 100. A variety of different cartridges of different lengths and diameters can be used without modifying the autoinjector 100. The resilient action of the end portions 343 adjusts the position of the locking teeth 340 so that surface 342a contacts the insert 160.

[0045] The cartridge container 140 further has a pair of holes 141a and 141b that are shaped on opposite sides of the body 141. The holes 141a and 141b allow viewing the contents of the cartridge 160, so that the user can visually check the drug before using the auto-injector 100. Before use, the holes 141a and 141b are aligned with the respective holes in the cover element 150, so that the user can see the content of the insert 160 through the outer body 110. The projection 149 having a series of reinforcing ribs 149a is formed at one end of the opening 141. The projection 149 contacts the edge 154a of the opening 154 in the shield element 150 to prevent any further forward movement of the needle shield 150 relative to the cartridge container 140, so the needle shield 150 cannot pull out of the outer body 110. When in this position, the locking surface 243 of the locking wings 240 engages with the tip of the needle shield 150 to prevent the needle shield 150 from sliding back into the outer body 110. When the projection 149 contacts the edge of the hole in the needle shield 150, the holes in the cartridge container and needle shield are no longer ripped off, so the user cannot see the cartridge 160 through the outer body 110. This provides a visual indication to the user that the autoinjector 100 has been used.

[0046] At present, the needle shield 150 will be described in more detail with reference to Figures 12-15, 38, 42, 43 and 53-54. The needle shield 150 has a generally elongated, hollow body 151 having a complementary shape to the shape of the outer body 110. The elongated body 151 enters with the possibility of sliding into the outer body 100. One end of the hollow body 151 is tapered and has a closed face 152. The front surface 152 has an aperture 152a sized to pass through the needle of the cartridge 160 during the injection procedure as shown in Figures 7 and 8. The front surface 152 is intended to be placed on the injection surface when using the autoinjector 100. The needle cover spring 153 is compressed between the front surface 152, a needle protector 150 and a cartridge container 140, as shown in figures 1, 2, 4, 5, 7 and 9. The autoinjector 100 with the needle protector 150 of the present invention is designed to function like autoinjectors without the needle protector in that a similar actuating force is required to start the autoinjector. Therefore, spring 153 has very little force. The pressure force for the cover 150 is less than the actuation force of the autoinjector 100. The maximum force for spring 153 is preferably 1.5 pounds. The force is less than the actuation force (1.5 versus 4 - 8) required to start the autoinjector 100, so the needle shield 150 does not affect the function of the autoinjector 100 compared to injectors without the shields such as disclosed in the '893 patent. The ribs 145 on the cartridge container 140 operate to stabilize the spring 153 within the sheath 150. The hollow body 151 may have cutouts 151a shown in figures 53 and 54. Cutouts 151a reduce the thickness of the plastic to save materials.

[0047] The hollow body 151 further has a pair of holes 154 formed therein. As discussed earlier, the holes 154 are in tune with the holes 141a and 141b in the cartridge container 140 before actuation to allow viewing of the drug in the cartridge 160. The edge surface 154a of the holes 154 is to contact with protrusion 149 to prevent the needle shield 150 from moving further.

[0048] The slots 155 are made on opposite sides of the needle shield 150. slots

155 are positioned to mate with the locking wings 240 and locking teeth 340. The slots 155 guide and support the locking wings 240 before the needle shield 150 extends. A transverse slot 155a may be introduced to assist in the assembly of the autoinjector 100 so that the locking teeth 340 can be inserted into the refill container 140 through the slot 155 in the needle shield 150. The bearing surface 344 can be introduced through the slot 155a. The locking projections 156 protrude inwardly into the slot 155. The locking projections 156 are configured to engage the locking surface 347a on the locking teeth 340. A series of projections are used.

156 corresponding to a series of slots 147 in the cartridge container 140 for support axles 341.

[0049] The inner groove 157 is made inside the hollow body 151. The inner groove 157 is axially aligned with the slots 155. A portion of the compression part 241 is positioned in the groove 157 when the cover 150 is in the position shown in Fig. 12

13. The grooves are aligned with the locking wings 240 to provide support and prevent buckling of the locking wings 240.

[0050] The insert 160 is usually an elongated glass tube having an opening 161 at one end, sized to allow the insertion of the piston 438 and the sleeve 430. The flange 436 on the sleeve 430 is intended to contact the end of the insert 160 to limit the movement of the piston and the sleeve in towards the inside of the cartridge 160 to control the dose administered through the needle 162. The needle 162 is attached to the tip assembly 163, which is attached to the other end of the cartridge 160. The tip assembly 163 may have a membrane 164 to prevent liquid drug from flowing through the needle 162 prior to operating the autoinjector. The needle 162 is placed in a protective sheath 165. The sheath 165 is attached to the tip assembly 163. Needle 162 pierces the sheath 165 during surgery when the needle 162 protrudes through the needle sheath 150. As shown, the cartridge 160 is a container for a dose of liquid drug. It is not intended to restrict the autoinjector 100 to use only one liquid; rather, it is contemplated that the cartridge 160 may store one or more liquids that mix when the autoinjector 100 is started. In addition, the cartridge 160 may store solid drug and liquid separately, the solid drug being dissolved in the liquid prior to administration.

[0051] The operation of the autoinjector 100 will now be described in more detail. The autoinjector 100 is shown in an inactive state in Figures 1, 2 and 3. The release pin 120 is fixed in place such that the pin 125 enters the hole 234 and the hole 435a in the sleeve 430, therefore, side arms 433 cannot be bent inward. In this position, the needle shield 150 is held in the locked, retracted position by the locking teeth 340. The locking surfaces 347a are pressed by the resilient end portions 343 to be aligned with the locking projections 156 on the needle shield element 150. In this position the autoinjector 100 cannot be used and the needle 162 is not exposed.

[0052] When it is desired to use the auto-injector 100, the release pin 120 grips the peripheral projection 124 and pulls to remove the release pin 120 from the end of the auto-injector 100. This prepares the auto-injector 100 for operation as shown in Figure 4. Tip 434a and 434b and side the arms 433a and 433b can now be squeezed together when the autoinjector 100 starts. At this point, the locking wings 240 are neither compressed nor stretched.

[0053] As shown in figures 5 and 6, the user presses the face surface 152 of the needle shield 150 to the injection site. This causes the pre-compressed spring 153 to be slightly more compressed until the needle protector 150 moves and makes contact with the face 145a of the cartridge container 140 (see Fig. 51), thus moving the projection 142 of the cartridge container 140 backwards. Spring force 153 is less than spring force 530. The needle shield 150, the cartridge container 140 and the cartridge 160 then move backward in the outer body 110. The cartridge container 140 moves upward in the inner body 110 until its projection 142 contacts the projection 335 of the internal body 330 of the drive assembly. The internal body 330 of the drive assembly as well as the sleeve 430 and the spring assembly 530 are then pushed backward inside the autoinjector 100 to the center of the external body 230 of the power unit. The sleeve 430 moves up until it contacts the sleeve actuating structure 239 shown in Figure 28. The tips 434a and 434b are in contact with the oblique actuation surface 239a. The tips 434a and 434b are squeezed together by the slanting surface 239 as the sleeve 430 moves backwards, so the tips 434a and 434b are released from the sleeve holding surface 332b. During this arming operation, the cover element 150 is slightly pressed back into the body 110. When this occurs, the initial loading of the locking teeth 340 with spring 153 temporarily disappears. Therefore, the V-shaped notch 347 temporarily detaches from the projection 156 formed on the needle shield 150. During this operation, projection 156 no longer contacts any of the surfaces 347a or 347b, but remains in the space created between the surfaces. Therefore, when the pressure of the cover member 150 has disappeared, the projection 156 will return to contact with the surfaces 347a or 347b. The locking teeth 340 completely release the cover member 150 only in response to movement of the cartridge 140 as it moves forward within the cartridge container 160. Accordingly, the cover element 150 cannot slide out as long as the insert 140 moves.

[0054] The spring 530 and the sleeve 430 simultaneously push the cartridge 160 and the cartridge container 140 forward toward the open end of the outer body 110. As soon as the needle 162 extends through the needle shield 150, the pressure of the drug inside the cartridge 160 interrupts the membrane 164 allowing drug flow to the user's body. The drug is forced through the needle 162, allowing the piston 438 and the sleeve 430 to move further inside the cartridge 160. The cartridge container 140 holds the sheath 165 and also prevents the transmission of spring force 530 through the cartridge 140 to the needle shield 150 and the injection site. That is, the force of the spring 530 that moves the cartridge 160 forwards opposes the front end of the cartridge container 140, with the sheath 165 compressed between them, and not the force directly on the needle sheath 150. Furthermore, the spring force of the needle guard is less than the actuation force required to compress the sleeve to release the sleeve during operation. Preferably, the needle guard spring force is about 0.25 to 0.75 of the minimum actuating force. The residual spring force of the drive assembly after actuation is within the cartridge container 140, cartridge 160, outer body 110 and outer body 230 of the drive assembly. Such a system advantageously prevents rapid return movement. Therefore, the auto-injector is not repelled from the injection site during actuation to ensure that the correct dose of drug is administered and the correct needle extension length or proper needle penetration depth is maintained. This phenomenon would occur if the spring force 530 were transmitted to the needle shield 150 and the injection site, whereby the autoinjector 100 could be pushed away from the injection site and change the position of the needle 162 within the injection site. This has a number of negative effects, including patient surprise; change from intramuscular to subcutaneous injection, which will affect marker levels. At the same time, the cartridge 160 moves forward within the cartridge container 140 (i.e., when the needle 160 moves from the retracted position to the extended position). The forward movement of the insert 160 causes the locking teeth 340 to rotate around the axle 341. This occurs in response to the cartridge 160 coming into contact with the bearing surface 342a and pushing the bearing surface 342a away from the main longitudinal axis of the needle 162. This rotation of the locking tooth 340 causes the locking surface 347a to detach from the locking projections 156. Surface 347b limits the rotation of the locking tooth 340. At this point, the sheath element 150 is in the unlocked position so that it can move relative to the cartridge container 140. Releasing the sleeve 430 from the retaining surface 332b, the sleeve presses the end of the internal body 330 of the drive assembly into contact with the external body 230 of the drive assembly.

[0055] As soon as the dose is injected into the user's body, the user subtracts the auto-injector 100 from the injection site. Since the needle shield 150 is not locked relative to the cartridge container 140, the spring 153 pushes the needle shield 150 out of the outer body 110 to cover the exposed needle 162 as shown in figures 9 and 11. Because the gap 155 is in tune with the groove 157 and the portion of the compression portion 241 is held in the slot 157, the portion of the compression portion 241 enters the groove 157 when the cover 150 moves outward. As the needle shield 160 slides outwardly, the locking wings 240 are momentarily compressed by the needle shield 160 as the thicker compressed portion 241 slides through the groove 157. This compression occurs when the lower surface of the groove 157 contacts the upper surface of the compression part 241. The wings 240 are compressed as indicated by the dashed lines in figure 52. As soon as the thicker compression part 241 leaves the groove 157 so that the wings 240 and needle shield 150 are in the position shown in figures 10, 14 and 15, the locking surface 243 contacts the end of the needle shield 150 to prevent the needle shield from sliding back into the outer body 110. Even when an inward force is applied, the compression parts 241 and 242 are compressed in such a way that the locking wing 240 is pressed against the body 141 of the cartridge container 140, so that the surface 243 remains engaged with the needle shield 150. This arrangement limits the inward movement of the needle shield 160. The projection 149 engages with the edge 154a of the opening 154 in the needle shield 150. The auto-injector 100 is now in the storage position without being able to use.

[0056] The invention has been disclosed with reference to the above embodiments and examples, additional variants will now become apparent to those skilled in the art. Various modifications and changes can be made to the self-injector described previously without departing from the scope of the present invention. The invention is not to be limited to the specific embodiment shown, and therefore the attached claims should be referred to, and not to the above discussion of preferred embodiments and examples, in order to assess the nature and scope of the invention in which exclusive rights are reserved.