Disposable auto injector

Abstract

To provide a disposable auto injector for injection of a certain prescription amount of medicine in a human body.SOLUTION: A dosage unit includes a first mechanical power source for supplying first mechanical force for moving a piston and carrying medicine into a human body. The auto injector 1 is provided with a second mechanical power source for supplying second mechanical force. The auto injector has a first state that a needle 4 is protected from a damage or contamination of the needle, a second state that the needle is ready to be punctured in the human body for dosage, a third state that the needle is punctured in the human body and dosage is ready, and a fourth state that the needle is protected for avoiding unintended puncture of the needle. The second mechanical power source 11 is configured to shift the state of the auto injector from the third state to the fourth state by releasing the second mechanical force.SELECTED DRAWING: Figure 5A

Description

Technical Field

[0001] The present invention relates to a disposable autoinjector for injecting a certain prescribed amount of medicine into the human body.

Background Art

[0002] Medication is increasingly being administered more frequently at the recipient's home. This implies that dosing and handling of equipment, such as syringes, must be simple and safe enough to handle. When administering medicine in a hospital, it is highly possible to use highly specialized equipment that includes more various options for adjusting the equipment to ensure proper dosing.

[0003] Medicines are very expensive, some of which are harmful to healthy people and some are even toxic. Therefore, when administering these medicines, for example, by syringe, it is very important that all of the single-dose amount is injected into the patient and that other people assisting the recipient of the medicine, for example, are protected from the needle after using the syringe. Furthermore, it has been found that users who feel discomfort and anxiety during injection often handle the syringe or equipment in an inappropriate manner. For example, the needle may be mishandled and contaminated before use or due to the illness of the medicine recipient. Therefore, it is important to protect the needle before use and to dispose of the disposable autoinjector safely when discarding it into a sharps container or trash can. Regarding dosing at home, the user who activates and handles the autoinjector may not be the actual recipient of the medicine, and therefore needle protection is important to avoid the risks associated with handling the disposable autoinjector for such users.

[0004] Many such medicine autoinjectors are driven by an electric motor powered by a battery, and therefore such autoinjectors may not be disposed of properly in the trash from an environmental perspective after injecting the medicine.

Summary of the Invention

[0005] An object of the present invention is to overcome, wholly or in part, the above-mentioned disadvantages and drawbacks of the prior art. More specifically, it is an object to provide an improved disposable auto-injector that can even be directly discarded into a normal trash can.

[0006] A further object is to provide an improved disposable auto-injector that protects the needle after use.

[0007] Yet another object of the present invention is to provide an improved disposable auto-injector that eliminates the risk of breakage of a container / cartridge containing a drug.

[0008] It is an object of the present invention to provide an improved disposable auto-injector that minimizes noise and / or tactile operations, such as vibrations generated from the injector mechanism during use.

[0009] Along with a plurality of other objects, advantages, and features that will become apparent from the following description, the above objects are A disposable auto-injector for injecting a prescribed amount of a drug into a human body, comprising a housing, a dosing unit disposed at at least a part of the housing, a needle, a drug container containing a drug, a plunger movable within the container, a first mechanical power source for supplying a first mechanical force for moving the plunger via a shaft to convey the drug to the human body, an actuating mechanism configured to release the first mechanical force of the first mechanical power source, and a mechanical de-advancing mechanism for controlling the movement of the plunger via the shaft, the dosing unit, The auto-injector comprises a second mechanical power source for supplying a second mechanical force, and the auto-injector has a first state in which the needle is protected from damage or contamination of the needle, a second state in which the needle is ready to pierce the human body for drug administration, a third state in which the needle is pierced into the human body and ready for drug delivery, and a fourth state in which the needle is protected to avoid unintentional needle pricks, The second mechanical power source is configured to shift the state of the auto-injector from the third state to the fourth state by releasing the second mechanical force, which is achieved by the solution according to the present invention by a disposable auto-injector.

[0010] The disposable auto-injector according to the present invention may further comprise a shield configured to protect the needle in the fourth state.

[0011] Furthermore, the second mechanical force can move the shield from the retracted position in the third state to the protruding position in the fourth state to protect the needle.

[0012] Furthermore, by moving the needle and the drug container, or the entire drug delivery unit, into the housing, the second mechanical force can move the needle into the housing from the third state to the fourth state.

[0013] Furthermore, the second mechanical force can be generated by retracting the shield into the housing.

[0014] Furthermore, the second mechanical force can be generated by applying a load to a spring.

[0015] Furthermore, the second mechanical force may be a spring.

[0016] The second mechanical force can be generated by retracting the drug delivery unit into the housing.

[0017] Furthermore, the second mechanical power source may have a load applied thereto in advance by the second mechanical power.

[0018] The disposable autoinjector described above may further comprise a locking element configured to lock the autoinjector in a fourth state, thereby locking the needle in its final position.

[0019] Furthermore, the disposable autoinjector may further comprise a lid or a cap.

[0020] The disposable autoinjector may further comprise a needle cap.

[0021] Again, the second mechanical power source may be a spring.

[0022] Furthermore, the actuating mechanism may be configured to actuate the third mechanical power of the third mechanical power source so as to project the needle from the housing.

[0023] The aforementioned actuating mechanism may be actuated by manual force from the user.

[0024] The disposable autoinjector described above may further comprise a dosing lock configured to prevent unintentional actuation of the dosing unit.

[0025] Furthermore, the first mechanical power source may be a helical torsion spring. In this way, it is possible to achieve the transmission of the force from the spring due to the torque from the spring. In this way, it is possible to achieve an ergonomic and compact design. Furthermore, by using a helical torsion spring, it is possible to adapt the spring force in a way that affects minimizing the size of the spring.

[0026] The above disposable autoinjector may further include a mechanical transmission mechanism for controlling the transmission of power to the shaft, and the mechanical transmission mechanism includes a first gear wheel that engages the first mechanical power source and the mechanical disengaging and engaging mechanism in order to transmit the power of the first mechanical power source to the shaft. The disengaging and engaging mechanism may be regarded as a mechanical brake. The disengaging and engaging mechanism may also be regarded as acting as a viscous damper, and in this context, the viscous damper is also regarded as a mechanical brake.

[0027] Furthermore, the mechanical transmission mechanism may include a shaft. During the movement of the plunger, the shaft is connected to the piston / plunger, the shaft has teeth, and the teeth of the shaft may engage with the gear wheel of the transmission mechanism. The shaft may be arranged at a position where it does not contact the plunger. That is, there is a gap. In this way, it is easy to install the container or cartridge. Furthermore, by having a gap, it is achieved that, for example, during transportation, due to slight movement, unintentional movement of the shaft and thus the plunger does not occur. This unintentional movement may lead to the loss of essential medicine.

[0028] An autoinjector device driven by an internal force such as the force of a spring usually requires a clearance (gap) between the plunger and the shaft when the plunger and the shaft are individually inserted into the device during assembly initially, i.e., before use. This is due to the required tolerances of the medicine container in combination with the tolerances of the various parts of the autoinjector, for example, to insert the container into the injector. Furthermore, there is often a gap due to the fact that after filling the container with medicine, the plunger may be slightly pushed into the container with respect to the rim of the container. Therefore, a clearance, a gap, is required to insert the container in a direction perpendicular to the movement of the shaft.

[0029] Due to the gap, i.e., the fact that the shaft and the plunger are not initially in contact with each other, the lack of backpressure from the plunger causes the shaft to be accelerated towards the plunger when the spring force is released, and thus the speed of the shaft increases. When the end (tip) of the shaft reaches the plunger, the speed and the resulting kinetic energy reach the maximum level, and thus, when the impact occurs between the plunger and the shaft, the impulse transmitted to the plunger is also maximized. The aforementioned impulse will be at least partially transmitted to the plunger. Therefore, depending on the time profile of the impact between the end of the shaft and the plunger, the device may be subject to high forces and stresses leading to deformation of each component or damage to the device or the container.

[0030] If the impact time is long and the deceleration is slight, the reaction force may not be large, but if the impact time is short / transient, the deceleration amount is large and the reaction force can still be large. The design of the interface that is subject to the impact affects the reaction force. Therefore, high reaction forces can exist at some interfaces of the system depending on the rigidity of the components and how the energy is distributed.

[0031] Anticipating the behavior of the connections of each interface so that none of the parts of the system are subject to high forces / stresses during high-speed / high-impact is a large and complex task. Therefore, it is difficult to conclude that no failure will occur, i.e., to guarantee the robustness of the system.

[0032] Instead of ensuring the overall rigidity of the auto-injector during the impact, control of the mechanical mechanism is provided after the operation by controlling the speed of the drive mechanism, i.e., the shaft, by the kinetic energy and impulse of the present invention.

[0033] Generally, in order to have a constant velocity in a certain direction, the sum of forces must be zero. For the system to move, it is necessary to have a positive force in the direction of movement. If only a slight increase in velocity is required, the acceleration, and as a result the force, must be non - negligible.

[0034] Using a deceleration mechanism that is a mechanical damper / brake achieves several advantages. The brake / damper is most often velocity - dependent, meaning that as the velocity increases, the resulting force also increases. The force, with respect to the damper and velocity, is determined by the damping constant (Force = c*v). This is advantageous because it is intended that the damper act while the shaft moves within the clearance and not during dosing, i.e., not necessarily during the process of pushing the drug out of the container. Thus, during the administration of a highly viscous drug, only minimal damping or braking is achieved. In this way, a stronger spring can be used without the risk of damaging the device / injector, and the device can be used for a wider range of viscosities. However, when a low - viscosity drug is pushed out of the container, a slight back - pressure from the drug occurs. In this situation, the attenuation using the deceleration mechanism provides a slower and smoother way of prescribing the drug. In this way, the risk of damaging the drug is minimized. Additionally, the risk of discomfort to the user during injection is minimized.

[0035] Since the deceleration mechanism acting as a damper is velocity - dependent and the velocity during dosing is relatively low, the force acting in the reverse direction from the damper is also small. Therefore, it is possible to specify the deceleration mechanism (damper) to provide a specific damping constant and thereby control the velocity of the drive mechanism to reach a balance with a specific desired force. In this way, the control of the impact between the shaft and the plunger is achieved. Thus, by increasing the overall rigidity of the device, the risk of device failure, such as the risk of container breakage, is reduced.

[0036] In one embodiment, the shaft may be bendable.

[0037] The shaft may comprise a curved shaft or a curved piston rod. The shaft may be a curved shaft or a curved piston rod at the position where it is attached.

[0038] Furthermore, the force acting from the spring of the first mechanical power source on the piston or the shaft may be 1 N to 100 N, or preferably 2 N to 75 N, or more preferably 3 N to 50 N, or even more preferably 4 N to 25 N. In this way, different types of drugs with different properties, for example with respect to viscosity, can be injected. Furthermore, the required force may vary depending on the specific point on the body where the drug is injected.

[0039] Furthermore, the housing may comprise a first carrier plate having a hole through which at least the shaft of the gear wheel of the mechanical transmission mechanism extends.

[0040] Furthermore, the housing may comprise a second carrier plate arranged on the side opposite to the first carrier plate, and at least a part of the transmission mechanism may be arranged between the first carrier plate and the second carrier plate.

[0041] The second carrier plate may have a notch for forming a space for the drug container.

[0042] Furthermore, the gear wheel may have a shaft and may be formed of metal, for example stainless steel.

[0043] Furthermore, the gear wheel may be formed of plastic or may be partially formed of metal if the shaft of the gear wheel is formed of metal.

[0044] Also, the carrier plate can be formed of a plastic such as nylon, and at least the tapered end of the shaft can be formed of metal.

[0045] By having a plate formed of nylon and a shaft end formed of metal, a lubricant is not required. In a syringe for transporting medicine, a lubricant is not allowed because there is a risk that such a lubricant may enter the human body. It is not allowed for a lubricant to enter the human body.

[0046] Furthermore, the risk of lubricant deterioration may weaken the gripping function of the syringe, thereby endangering the health of the end user.

[0047] The cartridge may have a capacity of 0.25 ml to 50 ml. The capacity of the cartridge may be greater than 10 ml. With a disposable auto-injector, the dosage injected into the human body may be in the range of 0.25 ml to 10 ml, preferably in the range of 0.5 ml to 7.5 ml, more preferably in the range of 0.75 ml to 5 ml, and even more preferably in the range of 1 ml to 2.5 ml.

[0048] The needle can protrude and / or retract by a distance of 1 mm to 75 mm, preferably 2 mm to 65 mm, or more preferably 3 mm to 55 mm, or even more preferably 4 mm to 45 mm, or most preferably 5 mm to 35 mm, from state 1 to state 4.

[0049] The needle may have a nominal outer diameter of about 0.3 mm to 0.8 mm, i.e., a needle gauge of about 30G to 21G.

[0050] Furthermore, the mechanical deceleration mechanism may include a deceleration gear wheel that engages with the mechanical transmission mechanism, and an anchor wheel having a mass displaced from the rotation point of the anchor wheel. In this way, by stopping the movement of the piston rod / shaft, it is possible to stop the forward movement of the piston / plunger. The mechanical deceleration mechanism may also be named a brake, a damper, or a deceleration brake. The deceleration mechanism meters out the time of applying force from the first mechanical force in an individual manner. In this way, regardless of the back pressure applied to the piston rod / shaft, only the desired force is released. Therefore, there is no risk that the force applied to the plunger will become excessive when the shaft / rod comes into contact with each other, for example due to a gap. If there is no mechanical deceleration mechanism, movement of the piston / shaft based on the potential energy from the unattenuated or uncontrolled spring force may form kinetic energy that may damage the container / cartridge or the injector.

[0051] Furthermore, it is possible to control the movement of the shaft / piston rod before the shaft / piston rod contacts the plunger / piston. In this way, the risk of damage to the container due to contact is eliminated. After the container / cartridge is inserted, there may be a gap between the contact end of the shaft and the plunger / piston. If the shaft moves so as to contact the plunger / piston with excessive force, the risk of damage to the container / cartridge is high, thereby creating a dangerous situation for the user and wasting important and expensive medicine.

[0052] The anchor wheel may include at least one second material to increase the mass of the anchor wheel. The second material may be a metal. The second material may be completely enclosed within the anchor wheel, for example during a molding process.

[0053] Finally, the dosage to be injected into the human body may be in the range of 0.25 ml to 10 ml, preferably in the range of 0.5 ml to 7.5 ml, more preferably in the range of 0.75 ml to 5 ml, and even more preferably in the range of 1 ml to 2.5 ml.

[0054] The present invention and many of its advantages will be described in more detail below with reference to the accompanying schematic drawings that illustrate several non-limiting embodiments for purposes of explanation.

Brief Description of the Drawings

[0055]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 4a

Figure 5A

Figure 5B

Figure 5C

Figure 5D

Figure 5E

Figure 6A

Figure 6B

Figure 6C

Figure 6D

Figure 7A

Figure 7B

Figure 7C

Figure 8A

Figure 8B

Figure 8C

Figure 9A

Figure 9B

Figure 9C

Figure 10A

Figure 10B

Figure 10C

Figure 11

Figure 12

Figure 13

Figure 14A

Figure 14B

Figure 14C

Figure 14D

Figure 15A

Figure 15B

Figure 15C

Figure 15D

Figure 15E

Figure 15F

DETAILED DESCRIPTION OF THE INVENTION

[0056] All the figures are highly schematic and not necessarily to scale. These figures show only those parts necessary to explain the present invention, and other parts are either omitted or merely suggested.

[0057] Figure 1 shows a disposable autoinjector 1 for injecting a prescribed dose of a drug into the human body. The disposable autoinjector 1 is shown in a first, initial state in which the needle is protected from damage and / or contamination of the needle. The cap 10 is shown attached to the housing 2. In Figure 2, the cap 10 of the disposable autoinjector has been removed, and the disposable autoinjector is in a second state in which the needle is ready to be inserted into the human body for drug administration. The disposable autoinjector 1 comprises a housing 2 and a dosing unit 3 at least partially within the housing, whereby the needle 4 of the dosing unit 3 projects from the housing. It can be seen that the housing 2 of the disposable autoinjector may have a generally square cross-section with rounded corners of the housing. A part of the outer surface of the disposable autoinjector may have a semi-circular outline, for example, to achieve a better ergonomic arrangement within the user's hand. The housing may have a size such that the ratio of a first dimension FD to a second dimension SD measured in cross-section is greater than 2:1. The dimensions are measured in the same cross-section. This plane is perpendicular to the longitudinal axis of the disposable autoinjector.

[0058] The dosing unit 3 shown in FIG. 3 includes a needle 4 and a medicine container 5 containing medicine. The medicine container 5 may be a needle supported by a support column, a syringe, or a cartridge to which the needle is attached. The dosing unit 3 further includes a first end 41. The dosing unit 3 further includes a first carrier plate 43 and a second carrier plate 45.

[0059] In the exploded view of the dosing unit 3 shown in FIG. 4 (and FIG. 4a), a piston 6 is movably disposed within the medicine container 5. The piston 6 (plunger) pushes the medicine out of the container 5 via a foldable shaft 22. A force is applied from a first mechanical power source 7 in the form of a helical torsion spring, thus supplying a first mechanical force for moving the piston to convey the medicine to the body (not shown). It can be seen that the helical torsion spring 7 acts in such a way that the torque transmitted from the helical spring is transmitted to the first gear wheel 20. The dosing unit 3 further includes an actuating mechanism 8 (shown in FIG. 5A) configured to release the first mechanical force of the mechanical power source 7. The dosing unit 3 includes a mechanical freewheel mechanism 9 for controlling the movement of the piston 6 by controlling the rotational speed of the mechanical power source, i.e., the conveyance of the force from the helical torsion spring 7. The freewheel mechanism 9 includes an anchor wheel 25 having a certain mass. The freewheel gear wheel 24 interacts with the arm of the anchor wheel 25 and brakes the operation of the shaft 22 by changing the rotational direction of the anchor wheel 25. In this way, it is achieved that simple control of excessive force of the spring 7 is possible, thereby enabling the administration of medicines with greatly different viscosities over the same time span. This also implies even highly viscous medicines that require applying a large force to the plunger.

[0060] Referring again to FIG. 4 and partially to FIG. 4a, the dosing unit 3 further comprises a mechanical transmission mechanism 19 for controlling the transmission of force to the piston 6. The mechanical transmission mechanism 19 comprises a first gear wheel 20 for engaging the first mechanical power source 7 and the mechanical clutch mechanism 9 in order to transmit the power of the first mechanical power source 7 to the piston 6. The mechanical transmission mechanism 19 comprises a shaft 22 connected to the piston / plunger 6, which shaft has teeth 23. These teeth 23 engage with a gear wheel 28 of the transmission mechanism 19. The shaft 22 is bendable so that it can slide along the rounded corners of the generally square-shaped housing 2. In this way, it is achieved that the overall size of the disposable autoinjector 1 can be reduced. The shaft 22 is arranged at the first end 41 of the disposable autoinjector 1, and the needle 4 is arranged at the second end 42 opposite the first end. As shown in FIG. 4, the disposable autoinjector has a first carrier plate 43 forming a base plate having a guide portion 44 for guiding the shaft when moving. The disposable autoinjector 1 further comprises a second carrier plate 45 forming a cover portion of the dosing unit 3, as shown in FIG. 3. The second carrier plate 45 has a cutout 46 so as to provide a space for the medicine container 5.

[0061] The mechanical clutch mechanism 9 includes a clutch gear wheel 24 that engages with the mechanical transmission mechanism 19, and a pawl wheel 25 having a pawl mechanism 26 with pawls 9a, 9b (shown in detail in FIG. 15). In this way, when the first mechanical power source 7 applies a force to rotate the first gear wheel 20 of the mechanical transmission mechanism 19, and thus moves the shaft and the piston, the gear wheel 24 engages with the first gear wheel 20. The clutch gear wheel 24 engages with the pawl mechanism 26. When the gear wheel 24 rotates, the pawls 9a, 9b of the pawl mechanism 26 engage and disengage such that when pawl 9a disengages from the gear wheel 24, pawl 9b engages with the gear wheel 24, or vice versa. This changes the rotational direction of the pawl wheel 25 every time the engagement with the gear wheel 24 switches between the two pawls 9a, 9b. Each time the rotational direction of the pawl wheel 25 reverses, since the pawl wheel 25 has the mass to be accelerated and decelerated, this restricts the rotational speed of the gear wheel 24, and thus the speed of the shaft 22. This then controls the speed of the shaft and thereby the plunger 6.

[0062] FIG. 4A shows an enlarged view of the gap AG between the plunger and the first end 22a of the shaft / piston rod 22. When the gap AG exists, the initial movement of the shaft 22 does not generate back pressure from the plunger / piston 6. For this reason, in the absence of a mechanical clutch mechanism (the situation is not shown), if all the potential energy of the spring is released too quickly, the shaft 22 could potentially damage the container or cartridge 5. The reason for this is that the shaft 22 would cause a sudden shock to the container 5 due to the impact between the first shaft end 22a and the plunger 6.

[0063] Each time the potential energy from the helical torsion spring 7 is released (see Figure 4), the mechanical ejection mechanism 9 ensures that the same amount of energy is released in the spring as long as sufficient force is available. In this way, it is controlled so that there is sufficient force to move the plunger 6 throughout the container, that is, not only is sufficient spring force applied from the shaft to the plunger, but also the resulting applied force is below the level that would cause damage to the container 5 when the first impact between the shaft and the plunger occurs safely. Although shown in Figure 4a, the reference numerals not discussed are shown for the purpose of associating Figure 4a with Figure 4.

[0064] Figures 5A - 5E show that the disposable autoinjector 1 further comprises a second mechanical power source 11 shown for supplying a second mechanical force. The second mechanical power source 11 is configured to maintain the shield 14 in a protruding state as long as excessive force is not applied to the shield 14 in the longitudinal direction, that is, horizontally with respect to the needle, with respect to the force of the second mechanical power source. Such excessive force can be applied by the user by applying a force to the shield 14 towards the human skin / body 12. The second mechanical power source 11 shifts the state of the disposable autoinjector 1 from a third state where the needle is stabbed into the human body 12 shown by the dashed line (Figure 5C) and the drug administration is ready, to a fourth state where the needle is protected to prevent unintentional stabbing. The shift of the state from the third state to the fourth state is carried out by releasing the second mechanical power / force from the second mechanical power source 11.

[0065] The disposable autoinjector 1 is shown in its first position in Figure 5A in its first state where the needle 4 is hidden and protected from damage or contamination. The lid or cap 10 is attached to the housing 2. The lid 10 is shown including a further protective part for the needle 4. The further protective part of the needle extends inside the shield 14.

[0066] Figure 5B shows the disposable autoinjector 1 in its second state. The cap / cover 10 has been removed and the needle 4 is ready to be inserted into the human body to administer a medicine such as a drug to treat or relieve a patient's pain.

[0067] In Figure 5C, the disposable autoinjector 1 is shown in its third state. In this third state, the needle 4 is inserted into the human body 12 (the body's skin is shown by the dashed line), and the disposable autoinjector 1 is ready to administer the medicine to the human body 12, for example, into the skin layer. When inserting the needle 4 into the body, it is shown that the shield 14 is pushed into the housing 2. When pushing the shield 14 into the housing 2, the spring 11, that is, the second mechanical power source, is pulled and is ready to push the shield back to its position in state 2 (shown in Figure 5B).

[0068] Figure 5D shows an intermediate state of the disposable autoinjector 1 in which the locking element 15 is activated. The locking element 15 is activated when the button 8 is pressed. Pressing the button 8 also starts the injection of the medicine. The intermediate state in Figure 5D occurs when moving the disposable autoinjector 1 from the third state to the fourth state.

[0069] The disposable autoinjector 1 is shown in a fourth state in FIG. 5E. In the fourth state, the needle is protected to avoid unintentional needle sticks. Thus, the disposable autoinjector 1 can be handled safely and even discarded in a conventional household trash can. For this reason, the disposable autoinjector 1 operates completely mechanically and does not require a battery or electrical wiring. For this reason, the disposable autoinjector 1 of the present invention will be environmentally appropriately discarded in a conventional trash can. Further, the disposable autoinjector 1 can be easily stored in a refrigerator. Refrigerators are often the optimal storage location for autoinjectors with pre-inserted drugs. However, storing in a refrigerator is often not good for the electrical components present in known syringes, and for this reason, it is often impossible to store the drug in the syringe. Thus, these syringes need to have a battery fitted or be otherwise prepared before use. This creates a risk that the user will be unable to do these things, and thus a risk of failure of such known syringes.

[0070] In FIGS. 5A-5E, the disposable autoinjector 1 includes a shield 14 configured to protect the needle in a fourth state. As can be seen from the figures, the needle 4 in FIGS. 5A-5E is also protected in a second state before the needle is injected into the human body 12, and for this reason, the needle 4 is also protected and thus hidden from the user. This is particularly useful for people with needle phobia (fear of needles). As shown in FIGS. 5B-5C, the second mechanical power of the second mechanical power source 11 causes the shield 14 to move from a protruding position in the second state to a retracted position in the third state when the needle 4 pierces the human body 12. When the shield 14 is pushed into the housing 2, the second mechanical power source 11, which is a spring, is extended or pulled, and for this reason, the second mechanical power is generated. As shown in FIGS. 5C and 5E, the second mechanical power of the second mechanical power source 11 moves the shield 14 from the retracted position in the third state to the protruding position in the fourth state to protect the needle 4.

[0071] The disposable autoinjector 1 of FIGS. 5A to 5E further includes a locking element 15 configured to maintain the disposable autoinjector 1 in a fourth state. This is done by locking the shield 14 in a protruding position where the shield 14 surrounds and protects the needle 4. The disposable autoinjector 1 further includes a dosing lock 16 configured to prevent unintentional actuation of the dosing unit before the needle 4 is safely injected into the human body 12 and the user is ready to receive the drug. The dosing lock 16 has an opening 17 that is not aligned with the locking element 15 when the disposable autoinjector 1 is in an inoperative state. In the operating state, the opening 17 is aligned with the locking element 15 such that, as shown in the intermediate position shown in FIG. 5D, the locking element 15 extends into the opening. After the injection of the drug is complete, the shield 14 protrudes from the housing 2 and the protruding shield extends beyond the locking element 15. For this reason, the locking element 15 can further protrude through the opening 17 and be positioned behind the shield 14, whereby the shield cannot be pushed back into the housing 2. As can be seen in FIG. 5A, the disposable autoinjector 1 further includes a needle cap 31. This needle cap 31 is configured as part of the lid 10. The dosing lock 16 is in contact with an actuating mechanism 8, such as a button, at one end of the disposable autoinjector, and the button cannot be pressed while the lid 10 is still attached to the disposable autoinjector 1.

[0072] As shown in FIGS. 6A to 6D, the actuating mechanism 8 is configured to actuate the third mechanical power of the third mechanical power source 18 so as to project the needle 4 from the housing 2. In FIG. 6A, the actuating mechanism 8 is prevented from projecting the needle from the housing by the safety portion 16b of the lid 10. The user activates the disposable autoinjector by removing the cap 10. FIG. 6B shows that although the cap 10 has been removed, the needle 4 is still retracted within the housing 2 and thus not visible to the user. In FIG. 6C, the actuating mechanism 8 is actuated by manual force from the user. When actuating the autoinjector, the third mechanical power source 18 applies a force to the dosing unit 3, whereby the needle 4 exits the housing 2 and the needle pierces the human body 12. When the disposable autoinjector 1 moves from the second state shown in FIG. 6B to the third state shown in FIG. 6C, the second mechanical power source 11 including a spring is loaded or pulled by the second mechanical power by compressing the spring 11, i.e., the second mechanical power source. The shield 14 is still maintained in the retracted position within the housing 2 due to one end of the shield 14 touching the user's skin. When the user pulls the disposable autoinjector 1 and thus withdraws the needle 4 from the human body 12, the second mechanical power source 11 automatically projects the shield 14 out of the housing 2, thereby protecting the needle 4. The locking element 15 ensures that the shield 14 is maintained and locked in the protruding position and thus the user and the person handling the disposable autoinjector are kept in a position protecting them from the needle 4.

[0073] In FIGS. 7A to 7C, the disposable autoinjector 1 is pre-loaded with the second mechanical power of the second mechanical power source 11, and after the dosing is completed, the needle 4 is moved into the housing 2 by the second mechanical power. That is, the needle 4, the medicine container 5, and the entire dosing unit 3 are moved into the housing 2 toward the first end 41, thereby moving from the third state to the fourth state. In this embodiment, the second mechanical power can be generated by applying a load to a spring when manufacturing the disposable autoinjector 1.

[0074] As shown in FIGS. 8A to 8C, the second mechanical power is generated by retracting the dosing unit 3 into the housing 2 when the needle 4 pierces the human body 12. Taking the dosing unit 3 and the needle 4 out of the housing may be done by the user. For this reason, the dosing unit 3 is moved, for example by the user, from the position in FIG. 8A to the state / position in FIG. 8B, whereby the dosing unit moves in the first direction from the first end 41 toward the second end 42. Then, after the injection is completed, the dosing unit 3 and the needle 4 are moved to the position shown in FIG. 8C by moving the dosing unit 3 in the second direction opposite to the first direction and thus toward the first end 41. At this position of the dosing unit 3 and thus of the needle 4, the needle is safely retracted into the housing, and the housing acts as a shield to prevent the needle from being stabbed. Depending on the level of safety, the lid 10 may be, for example, a membrane including an area that cannot be penetrated and is removed before the needle can protrude.

[0075] As can be seen in FIGS. 9A to 9C, the disposable auto-injector 1 has a second mechanical power of the second mechanical power source 11 pre-loaded. FIG. 9A shows that the lid 10 is still attached to the housing 2. After the lid 10 is removed, the shield 14 still protrudes from the housing 2, thus protecting the needle 4. When pressing the shield 14 towards the user's skin 12, a force is applied to the shield towards the inside of the housing 2, thus enabling the needle 4 to pierce the user's skin. After the dosing is completed, the user removes the disposable auto-injector 1. When the user removes the injector, the shield 14 remains in contact with the skin, and thus the needle 4 is always fully protected. The shield 14 is moved so as to protrude the shield 14 from the dosing unit 3 and is maintained in contact with the skin 12 by an additional second mechanical power 11B surrounding the needle 4. Further, after the dosing is completed, if the shield 14 is no longer in contact with the skin, the second mechanical power 11 moves the dosing unit 3 further into the housing 2 towards the first end 41 of the housing. When the needle pierces the human body 12, an additional second mechanical power is generated by compressing the spring 11B.

[0076] In FIGS. 10A to 10C, the second mechanical power source 11 is pre-loaded by a second mechanical power, for example a spring. At the end of the dosing, the second mechanical power source 11 is activated and the shield 14 protrudes to protect the needle 4.

[0077] In FIG. 11, the dosing unit 3 is shown in a perspective view and has a needle cap 31 that covers the needle 4 (the needle 4 is shown in FIG. 12). In the exploded view of FIG. 13, the dosing unit 3 has substantially the same elements and design as the dosing unit of FIG. 4, but in FIG. 13, the dosing unit 3 further includes a shield 14 and a needle cap 31. It can be seen that the needle 4 is fixedly attached to the container 5, for example as a stacked needle or syringe. Those skilled in the art will understand that different containers, such as a cartridge (as shown in FIG. 4), can be used.

[0078] The disposable autoinjector 1 shown in FIGS. 14A to 14D has a more square cross-sectional shape than the disposable autoinjector 1 shown in FIGS. 1 and 2. The disposable autoinjector 1 in FIG. 14A is shown in its first state, i.e., the state in which the lid or cap is attached, and in FIG. 14B, it is shown in its second state. In FIG. 14C, the needle 4 of the disposable autoinjector 1 is in its protruding position and the needle is inserted into a human body (not shown). In FIG. 14D, the disposable autoinjector 1 is in its fourth, protected state, in which the shield 14 surrounds the needle 4.

[0079] FIG. 15 shows the mechanical disengaging mechanism 9 and functions in detail. Braking is achieved by the rotation of the disengaging gear wheel 24, and when rotating, it is necessary to apply a force to the mechanical disengaging mechanism 9 by the disengaging gear wheel 24 so that it also rotates. The anchor mechanism includes anchors 9a, 9b attached to the anchor wheel 25. The anchors 9a, 9b of the mechanical disengaging mechanism 9 are configured to engage with the disengaging gear wheel 24 and shift the mass of the anchor wheel 25, that is, the rotational direction of the mass of the disengaging mechanism 9. This shift in the rotational direction of the anchor wheel 25, and thus the overall mass of the disengaging mechanism 9, results in a braking effect. The anchor wheel 25 shifts its rotational direction according to the arrows A1 and A2 in FIGS. 15C and 15F. The anchor wheel 25 rotates clockwise in FIGS. 15A and 15B, counterclockwise in FIGS. 15C, 15D, and 15E, and clockwise again in FIG. 15F. The disengaging mechanism 9 ensures that the main power source, that is, the first power source, releases its power in a controlled manner. In this way, the gap between the shaft and the plunger / piston inserted into the medicine container, that is, the clearance, prevents an unintended sudden impact from the shaft or the stem that could cause a failure or crack in the container.

[0080] Although the present invention has been described above in connection with preferred embodiments thereof, it will be apparent to those skilled in the art that some variations can be contemplated without departing from the invention as defined by the appended claims.

Claims

1. A disposable autoinjector (1) for injecting a prescribed dose of a drug into a human body (12), comprising: a housing (2); a dosing unit (3) disposed at least in part within the housing, the dosing unit including: a needle (4); a drug container (5) containing the drug; a plunger (6) movable within the container; a shaft having a first position spaced from the plunger and a second position in contact with the plunger; a first mechanical power source (7) for supplying a first mechanical force to move the plunger via the shaft to convey the drug to the human body; an actuating mechanism (8) configured to release the first mechanical force of the first mechanical power source; and a damper configured to oppose the first mechanical force when the shaft moves from the first position to the second position, wherein the dosing unit is provided; wherein the autoinjector includes a second mechanical power source (11) for supplying a second mechanical force, and the autoinjector has: a first state in which the needle is protected from damage or contamination; a second state in which the needle is ready to pierce the human body for drug administration; a third state in which the needle has pierced the human body and is ready for dosing; and a fourth state in which the needle is protected to avoid unintentional needle sticks, wherein the second mechanical power source (11) is configured to shift the state of the autoinjector from the third state to the fourth state by releasing the second mechanical force. The disposable autoinjector as described above.

2. The disposable autoinjector according to claim 1, further comprising a shield (14) configured to protect the needle in the fourth state.

3. The disposable autoinjector according to claim 2, wherein the second mechanical force moves the shield from a retracted position in the third state to a protruding position in the fourth state to protect the needle.

4. The disposable autoinjector according to any one of the preceding claims, wherein the second mechanical power moves the needle from the third state to the fourth state within the housing by moving the needle and the medicine container, or the entire dosing unit, into the housing.

5. The disposable autoinjector according to claim 2 or claim 3, wherein the second mechanical power is generated by retracting the shield into the housing.

6. The disposable autoinjector according to any one of the preceding claims, further comprising a locking element (15) configured to lock the autoinjector in the fourth state, thereby locking the needle.

7. The disposable autoinjector according to any one of the preceding claims, wherein the actuating mechanism (8) is configured to activate the third mechanical power of the third mechanical power source (18) so as to project the needle from the housing.

8. The disposable autoinjector according to any one of the preceding claims, wherein the actuating mechanism is actuated by manual force from a user.

9. The disposable autoinjector according to any one of the preceding claims, further comprising a dosing lock (16) configured to prevent unintentional actuation of the dosing unit.

10. The disposable autoinjector according to any one of the preceding claims, wherein the first mechanical power source (7) is a helical torsion spring.

11. The disposable autoinjector according to any one of the preceding claims, further comprising a mechanical transmission mechanism (19) for controlling the transmission of power to the shaft, the damper comprising a mechanical disengaging mechanism, and the mechanical transmission mechanism comprising a first gear wheel (20) for engaging the first mechanical power source (7) with the mechanical disengaging mechanism for transmitting the power of the first mechanical power source to the shaft.

12. The disposable autoinjector according to claim 11, wherein the mechanical transmission mechanism comprises a shaft (22) connected to the piston, the shaft having teeth (23), and the teeth of the shaft engaging the gear wheel (28) of the transmission mechanism.

13. The disposable autoinjector according to claim 12, wherein the shaft is bendable.

14. The damper includes a mechanical disengaging mechanism, and the mechanical disengaging mechanism includes a disengaging gear wheel (24) engaged with the mechanical transmission mechanism and the anchor wheel (26) having a mass displaced from the rotation point of the anchor wheel. The disposable autoinjector according to any one of the preceding claims.

15. The dosage to be injected into the human body is in the range of 0.25 ml to 10 ml, preferably in the range of 0.5 ml to 7.5 ml, more preferably in the range of 0.75 ml to 5 ml, and even more preferably in the range of 1 ml to 2.5 ml. The disposable autoinjector according to any one of the preceding claims.

Images