needle-free syringe

Abstract

The present invention provides a needle-free syringe for injecting a target substance into a target area without using an injection needle. The syringe comprises: a syringe body formed of a resin member; an igniter; a container for containing the target substance; and a piston configured to pressurize the target substance by utilizing the injection energy to advance through a specific passageway connected to a combustion chamber. A reinforcing member is provided within the syringe body. The reinforcing member is a cylindrical member formed of a metal member that surrounds at least the igniter and the combustion chamber and extends axially along the syringe body. The reinforcing member is disposed in a radially directed manner and is clamped by the syringe body. This structure of the needle-free syringe, which includes the igniter as a pressurization source, ensures sufficient strength to withstand the pressure generated by the igniter while avoiding degradation of user operability.

Description

Technical Field

[0001] The present invention relates to a needle-free injector for injecting an injection target substance into a target area without using an injection needle. Background Art

[0002] Needle-free syringes, which lack a needle, are an example of devices for injecting a target substance, such as a drug solution, into a target area within a living organism. However, recent developments have focused on ease of use and hygiene. Needle-free syringes require an actuator capable of providing a high level of energy to inject the drug solution into the target area, utilizing the energy of the drug solution to inject the drug into the target area. For example, an ignition actuator utilizing the energy generated by the combustion of gunpowder can be used.

[0003] For example, the ignition actuator described in Patent Document 1, though not intended for use in needle-free injectors but rather as a vehicle safety device, features an ignition element positioned within a cylindrical metal housing. This ignition element is positioned opposite a piston, and the piston is driven by combustion energy generated by the ignition element upon activation. The housing is then covered with a resin shell. This structure ensures the heat and pressure resistance of the combustion chamber within the ignition actuator.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 6632437 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] Needle-free syringes require the user to hold the syringe and place the syringe nozzle in contact with the area where the medication, etc., is to be administered. Therefore, increasing the size and weight of the syringe reduces user usability. On the other hand, when using a high-energy igniter as a pressurization source for the medication, etc., the syringe must be sufficiently strong to withstand the resulting pressure to ensure user safety. However, increasing strength typically requires the use of high-strength components such as metal in the syringe body or increasing the size of the syringe body itself, which reduces usability.

[0009] Therefore, in view of the above problems, the object of the present application is to provide a technology that can ensure sufficient strength to cope with the pressure generated by the igniter in a needle-free syringe having an igniter as a pressurization source while avoiding deterioration of user operability.

[0010] Technical Solution

[0011] To address these issues, the needle-free syringe disclosed in this application employs a structure in which a cylindrical reinforcement member formed of a metal component is embedded within a syringe body formed of a resin component. By making the syringe body composite, sufficient strength to withstand the pressure generated by the combustion of ignition powder in the igniter is ensured while minimizing the weight ratio of the metal component within the syringe body.

[0012] Specifically, the present application discloses a needle-free syringe for injecting a target substance into a target area without using an injection needle. The syringe comprises: a syringe body formed of a resin member; an igniter disposed within the syringe body that releases injection energy for injecting the target substance into a combustion chamber within the syringe body by burning ignition powder; a container disposed within the syringe body that has a storage space for accommodating the target substance and defines a flow path for injecting the target substance from an ejection port into the target area; and a piston configured to utilize the injection energy to advance through a specific passage within the syringe body that communicates with the combustion chamber, thereby pressurizing the target substance contained in the storage space. Furthermore, a reinforcing member is provided within the syringe body. The reinforcing member is a cylindrical member formed of a metal member that surrounds at least the igniter and the combustion chamber and extends axially along the syringe body. The reinforcing member is disposed radially within the syringe body so as to be clamped by the syringe body.

[0013] In this needle-free syringe, the igniter releases injection energy into the combustion chamber to inject the target substance into the target area. This injection energy pressurizes the piston, which in turn propels the piston through a specific passageway. This piston pressurizes the target substance within the container, causing the target substance to flow through the flow path of the container and be injected into the target area. In a needle-free syringe, the tip side refers to the side relatively close to the injection port, and the base side refers to the side opposite the tip side in the longitudinal direction (axial direction) of the needle-free syringe.

[0014] Among them, the injection target substance for injection with a needle-free syringe can be exemplified by a specific substance containing a component that is expected to have an effect in the target area or a component that is expected to exert a specific function in the target area. Therefore, as long as the injection can at least be performed using the above-mentioned injection energy, the physical form of the injection target substance is not limited. For example, the injection target substance can be present in a state of being dissolved in a liquid, or it can also be in a state of being merely mixed but not dissolved in the liquid. For example, the specific substances to be injected include vaccines for enhancing antibodies, proteins for beauty, cultured cells for hair regeneration, etc., and the injection target substance is formed by containing these substances in a liquid medium so that these substances can be injected. It should be noted that the above-mentioned medium is preferably a medium that does not impair the above-mentioned effect or function of the specific substance when injected into the target area. Alternatively, the above-mentioned medium can also be a medium that exerts the above-mentioned effect or function by interacting with the specific substance when injected into the target area.

[0015] Furthermore, in order to inject the target substance into the target area from a needle-free injector and deliver it into the interior, the injected target substance must penetrate the surface of the target area. Therefore, during the initial injection phase, the target substance must be injected into the target area at a relatively high velocity. Considering this, as an example, the igniter preferably utilizes combustion products released by the combustion of an ignition powder to provide injection energy. It should be noted that the ignition powder may be any of the following, or a combination thereof: a powder containing zirconium and potassium perchlorate, a powder containing titanium hydride and potassium perchlorate, a powder containing titanium and potassium perchlorate, a powder containing aluminum and potassium perchlorate, a powder containing aluminum and bismuth oxide, a powder containing aluminum and molybdenum oxide, a powder containing aluminum and copper oxide, or a powder containing aluminum and iron oxide. A characteristic of these ignition powders is that, even though their combustion products are gaseous at high temperatures, they contain no gaseous components at room temperature. Therefore, the combustion products condense immediately after ignition, enabling the igniter to provide injection energy in a very short time.

[0016] In the aforementioned needle-free syringe, the syringe body is formed of a resin material, and a cylindrical reinforcement member formed of a metal component is provided within the syringe body. Furthermore, the reinforcement member is provided within the syringe body so as to surround at least the igniter and the combustion chamber, that is, to accommodate at least the igniter and the combustion chamber within the inner space of the reinforcement member. The combustion chamber is the space where the igniter itself is located and where the pressure generated by the instantaneous combustion of the ignition charge is applied. Therefore, this arrangement allows the needle-free syringe to be constructed so that the high-strength reinforcement member can adequately withstand the pressure generated by combustion. Furthermore, the metal reinforcement member is clamped by the resin syringe body in the radial direction of the syringe body. Therefore, the syringe body, which is formed of a composite material of resin and metal, effectively enhances its resistance to the pressure generated by the injection energy that spreads radially around the igniter.

[0017] In addition, the above-mentioned reinforcing member can be a tubular member that can at least accommodate the igniter and the combustion chamber in the inner space, preferably a cylindrical shape. In the case of a cylindrical shape, pressure can be evenly withstood, and the strength of the syringe body can be more effectively improved. As an example, the tubular reinforcing member can be formed by a member consisting of a plate, or can also be formed by a member that has been specifically processed (such as a mesh member or a plate material processed by stamping metal). In addition, the reinforcing member can be formed by a tubular member, or can also be formed by appropriately combining a plurality of tubular members. Further, the reinforcing member can be a straight tubular member whose axial cross-sectional area is constant, or can also be a sleeve member whose axial cross-sectional area changes.

[0018] As described above, the needle-free syringe disclosed herein employs a structure in which a cylindrical reinforcement member formed of a metal component is embedded within the syringe body formed of a resin component. This ensures sufficient strength to withstand the pressure generated by the igniter while minimizing the weight ratio of the metal component within the syringe body. As a result, the needle-free syringe can be suitably miniaturized and lightweight, avoiding degradation of user operability. Furthermore, when a metal cylindrical member is generally used as the reinforcement member, it is relatively easy to obtain and process the cylindrical member. Consequently, the cost of manufacturing the needle-free syringe can also be reduced.

[0019] In the aforementioned needle-free syringe, the reinforcing member may extend axially along the syringe body, surrounding at least a portion of the specific passageway, in addition to the igniter and combustion chamber. The specific passageway is the space that propels the piston and, because it is connected to the combustion chamber, utilizes the energy generated by the igniter combustion to apply pressure. Therefore, by extending the reinforcing member to surround at least a portion of the specific passageway, the strength to withstand this pressure can be effectively enhanced.

[0020] Furthermore, in the syringe body of the needle-free syringe, the thickness of the syringe body forming the combustion chamber is set to be thinner than the thickness of the syringe body forming the specific passage. In this case, the thickness of the first portion of the reinforcing member surrounding the igniter and the combustion chamber can be set to be thicker than the thickness of the second portion surrounding the specific passage. In order to concentrate the energy generated by the igniter combustion on the piston and effectively propel the piston, the diameter of the specific passage is sometimes set to be thinner than the diameters of the igniter and the combustion chamber. As a result, the thickness of the syringe body forming the combustion chamber is sometimes thinner than the thickness of the syringe body forming the specific passage, and thus the strength of the former is more likely to decrease than the latter. Therefore, by setting the thickness of the first portion of the reinforcing member to be thicker than the thickness of the second portion, it is easy to ensure sufficient strength to cope with the pressure generated by the igniter combustion.

[0021] Furthermore, in the needle-free syringe, the reinforcing member may be formed by laminating a plurality of metal cylindrical sub-members having different diameters. Furthermore, the number of laminated sub-members corresponding to the first portion may be greater than the number of laminated sub-members corresponding to the second portion. By adjusting the number of laminated sub-members in this manner, the thickness of the first portion of the reinforcing member can be made thicker than the thickness of the second portion.

[0022] In addition, in the needle-free syringe described above, the syringe body can be constructed to include a first shell provided with the igniter and a second shell provided with the accommodating portion. Furthermore, when the reinforcing member is disposed on the surface of the first shell, or when the reinforcing member is disposed on the surface of the second shell, by attaching the first shell and the second shell to each other, the reinforcing member can be clamped between the first shell and the second shell. By constructing the syringe body from two shells in this manner, the reinforcing member can be easily disposed within the syringe body. It should be noted that any method can be used to attach the first shell and the second shell, such as screwing, snap-fit ​​fastening, or bolt fastening.

[0023] In the needle-free syringe described above, the piston's sliding surface may be formed on the surface of the syringe body forming the specific passage, and a cylindrical additional reinforcement member formed of a metal member may be provided. The provision of such an additional reinforcement member appropriately protects the specific passage from the pressure generated by combustion in the igniter, and the piston's sliding surface formed of the metal additional reinforcement member reduces frictional forces acting on the piston, enabling more efficient injection of the target substance.

[0024] Effects of the Invention

[0025] According to the disclosure of the present application, in a needle-free injector having an igniter as a pressurizing source, sufficient strength to cope with the pressure generated by the igniter can be ensured, and degradation of user operability can be avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the first diagram showing the schematic structure of a needle-less syringe.

[0027] Figure 2A yes Figure 1 AA cross-section of the needle-free syringe is shown.

[0028] Figure 2B yes Figure 1 BB cross-section of the needle-free syringe shown.

[0029] Figure 3 This is a second diagram showing a schematic structure of a needle-less syringe.

[0030] Figure 4 The third diagram shows a schematic structure of a needle-less syringe.

[0031] Figure 5 The fourth diagram shows a schematic structure of a needle-less syringe.

[0032] Figure 6 Yes Figure 4 The installation diagram of the first housing and the second housing in the needle-free syringe is shown.

[0033] Figure 7 FIG5 is a fifth diagram showing a schematic structure of a needle-less syringe. DETAILED DESCRIPTION

[0034] Below, with reference to the accompanying drawings, a needle-free syringe 1 (hereinafter referred to as "syringe 1") disclosed in this application will be described as an example. It should be noted that the various configurations and combinations thereof in the various embodiments described in this application are merely examples, and additions, omissions, substitutions, and other modifications to the configurations may be made as appropriate without departing from the scope of this application. This disclosure is not limited by the embodiments but only by the claims.

[0035] <First embodiment>

[0036] The syringe 1 is a needle-free syringe that utilizes the combustion energy of gunpowder to inject an injection solution, equivalent to the target injection substance of this application, into a target area. That is, it performs injection without using a needle. In this embodiment, the terms "top end side" and "base end side" are used to indicate the relative positional relationship of the syringe 1 along its longitudinal (axial) direction. The "top end side" refers to the position near the top end of the syringe 1, described below, i.e., near the ejection port 77. The "base end side" refers to the direction opposite to the "top end side" along the longitudinal direction of the syringe 1, i.e., the direction toward the igniter 22.

[0037] in, Figure 1 This is a cross-sectional view of the syringe 1, schematically illustrating the structure of the syringe 1. The syringe 1 includes an igniter 22, a syringe body 30, a container 70, a plunger 80, and the like. In the preparatory stage before activating the syringe 1, an injection solution is filled into the storage space 75 formed between the container 70 and the plunger 80 within the syringe 1. As described later in this application, the injection solution injected into the target area via the syringe 1 is formed by containing a specific substance in a liquid medium that exerts the desired efficacy and function on the target area. In this injection solution, the specific substance may be dissolved in the medium liquid or may be merely mixed and undissolved.

[0038] As the specific substance contained in the injection, for example, can cite can be to the biological body derived substance of the target area injection as organism or the material showing expected physiological activity, for example, as biological body derived substance, can list DNA, RNA, nucleic acid, antibody, cell etc., as the material showing physiological activity, can list the medicine that is made up of low molecule, protein, peptide etc., vaccine, inorganic substances such as metal particles for thermotherapy or radiotherapy, the material with various pharmacological and therapeutic effects containing as the carrier of carrier etc. In addition, as the liquid of the medium of injection, as long as be suitable for the material that these specific substances are cast in the target area, no matter how aqueous, oily. In addition, if specific substance can be injected by syringe 1, then as the viscosity of the liquid of medium is not particularly limited yet.

[0039] In the syringe 1, an ignition current is supplied to the igniter 22 from an external power source, thereby activating the igniter 22 and injecting the injection solution through the syringe 1. Various methods can be used to supply the ignition current to the igniter 22. For example, the power for activating the igniter 22 can be supplied externally via a power cord (not shown). Alternatively, a battery for supplying this power can be provided within the syringe 1.

[0040] The igniter 22 is an electronic igniter that burns the ignition charge to generate energy for injection. It has a cover 20 that is ruptured by the combustion products generated by the combustion of the ignition charge. When the igniter 22 is mounted on the injector body 30, the cover 20 is positioned at the combustion chamber 20a. When the igniter 22 is activated, the generated combustion products rupture the cover 20 and are released into the combustion chamber 20a.

[0041] The combustion energy of the ignition powder used in the igniter 22 serves as the energy used by the syringe 1 to inject the injection solution into the target area. It should be noted that the following gunpowders, or gunpowders composed of a combination of multiple thereof, are preferred as igniters: gunpowder containing zirconium and potassium perchlorate (ZPP), gunpowder containing titanium hydride and potassium perchlorate (THPP), gunpowder containing titanium and potassium perchlorate (TiPP), gunpowder containing aluminum and potassium perchlorate (APP), gunpowder containing aluminum and bismuth oxide (ABO), gunpowder containing aluminum and molybdenum oxide (AMO), gunpowder containing aluminum and copper oxide (ACO), and gunpowder containing aluminum and iron oxide (AFO). These gunpowders generate high-temperature, high-pressure plasma when burned immediately after ignition. However, when the temperature reaches room temperature and the combustion products condense, the generated pressure exhibits a characteristic of rapidly decreasing because they do not contain gas components. Ignition powders other than the above-mentioned gunpowders may also be used as long as they can inject an appropriate injection solution.

[0042] The internal space of the syringe body 30, where the combustion products are released from the igniter 22, forms the combustion chamber 20a. The combustion chamber 20a is a cylindrical space, and the igniter 22, which includes the cover 20, has a diameter large enough to fit within the combustion chamber 20a. Furthermore, the syringe body 30 is provided with a cylindrical internal space 36 that communicates with the combustion chamber 20a. A piston 40 is slidably disposed within internal space 36 together with an O-ring 25, which serves as a sealing member. Internal space 36 corresponds to the specific passage disclosed herein. Before the igniter 22 is activated, when the piston 40 is disposed within internal space 36, the flange surface 41 at the base end of the piston 40, acting as a pressure-receiving surface for the pressure generated by the combustion products from the igniter 22, is exposed to the combustion chamber 20a. The top end of the piston 40 is retracted within internal space 37, which is located on the top side of the syringe body 30 and communicates with internal space 36 to form a cylindrical shape. The diameter of internal space 37 is smaller than that of internal space 36.

[0043] Then, when the igniter 22 is activated to release combustion products into the combustion chamber 20a, the pressure therein rises, and the flange surface 41 on the base end of the piston 40 receives this pressure, pushing the piston 40 toward the tip. In other words, the syringe 1 uses the igniter 22 as a pressure source to drive the piston 40. It should be noted that because the diameter of the expanded flange surface 41 of the piston 40 is larger than the diameter of the internal space 37, the amount of movement of the piston 40 to press the plunger 80 is limited. It should be noted that the piston 40 can also be made of resin, in which case metal can also be used in portions requiring heat resistance and pressure resistance.

[0044] As another method for adjusting the pressure applied to the piston 40, a gas generating agent that generates gas by burning the combustion products from the igniter 22 may be further disposed in the combustion chamber 20a opposite the cover 20 of the igniter 22. This location is where it is exposed to the combustion products from the igniter 22. Alternatively, as disclosed in International Publication No. 01-031282 or Japanese Patent Publication No. 2003-25950, the gas generating agent may be disposed within the igniter 22. An example of a gas generating agent is a single-base smokeless powder composed of 98% by mass nitrocellulose, 0.8% by mass diphenylamine, and 1.2% by mass potassium sulfate. Various gas generating agents used in airbag gas generators or seatbelt pretensioner gas generators may also be used. By adjusting the size, dimension, shape, and especially the surface shape of the gas generator when arranged in the combustion chamber 20a, etc., the combustion end time of the gas generator can be changed, thereby adjusting the pressure applied to the piston 40 to the desired pressure.

[0045] Among them, the syringe body 30 is as follows Figure 1 As shown, the igniter 22, plunger 80, container 70, and other components are installed to form the main body of the syringe 1. The syringe body 30 can be made of a resin member such as known nylon 6-12, polyarylate, polybutylene terephthalate, polyphenylene sulfide, or liquid crystal polymer. Furthermore, these resins may contain fillers such as glass fiber or glass filler. For example, polybutylene terephthalate may contain 20-80% by mass of glass fiber, polyphenylene sulfide may contain 20-80% by mass of glass fiber, and liquid crystal polymer may contain 20-80% by mass of a mineral.

[0046] Furthermore, in the syringe body 30, an internal space 38 communicating with the internal space 37 is formed. Figure 1As shown, the internal space 38 is approximately the area where the plunger 80 is arranged, and is a cylindrical hollow area formed along the axial direction of the syringe body 30. The diameter of the internal space 38 is wider than the diameter of the internal space 37, forming a diameter within which the plunger 80 can slide. The plunger 80 is a component that uses the energy received from the piston 40 to pressurize the injection liquid. On its base end side, it has a plunger rod 50 that receives force from the piston 40, and on its top end side, it has a stopper 60 formed of an elastic member such as rubber and pressing the injection liquid. It should be noted that a penetration hole that penetrates into the internal space 38 can be formed on the outer surface of the side of the syringe body 30. The user can confirm the status of the plunger 80 in the syringe 1 from the outside through the penetration hole (for example, whether the syringe 1 is before or after activation, etc.).

[0047] Furthermore, an internal threaded portion 39a for mounting a container 70 is formed on the inner wall of the tip portion 39 of the syringe body 30. The container 70 is mounted on the syringe body 30 via the internal threaded portion 39a using a container holder 71, described below. The container 70 contains the injection liquid pressurized by the plunger 80 and also defines the flow path 76 for injecting the pressurized injection liquid from the injection port into the target area, serving as a container. With this in mind, the resin material used to form the container 70 can be selected, for example, the same resin material as that used for the syringe body 30.

[0048] The container 70 is a space for holding an injection solution. It has a storage space 75 formed as a stopper 60 for advancing the plunger 80, and a flow path 76 connecting the storage space 75 to an ejection port 77 facing the exterior of the container 70. The container 70, thus constructed, does not itself have an external threaded portion that screws into the internal threaded portion 39a of the syringe body 30. Therefore, the container 70 is attached to the syringe body 30 by the container holder 71. The container holder 71 holds the container 70 so that the ejection port 77 of the container 70 is exposed through an opening at its distal end. At this point, the container 70 is in a state where the injection target substance is filled in the storage space 75 and the plunger 80 is also loaded. Furthermore, while the container holder 71 holds the container 70, the external thread of the container holder 71 and the internal threaded portion 39a of the syringe body 30 are directly screwed together until the proximal end surface of the container 70 contacts the end surface of the syringe body 30. As a result, the tightening force generated by this screwing holds the container 70 between the container holder 71 and the syringe body 30. At this time, the plunger 80 is arranged so as to straddle the storage space 75 in the container 70 and the internal space 38 in the syringe body 30 .

[0049] The state where the container 70 is mounted on the syringe body 30 by the container holder 71 is as follows: Figure 1The state shown. When the igniter 22 is activated in this state, the piston 40 is pressurized by the combustion products generated thereby, and the plunger 80 slides in the internal space 38. As a result, the injection liquid contained in the storage space 75 is pressurized and injected from the injection port 77 through the flow path 76. Furthermore, the inner diameter of the flow path 76 provided in the container 70 is formed to be thinner than the inner diameter of the storage space 75. With this structure, the injection liquid pressurized to a high pressure is injected to the outside from the injection port 77.

[0050] It should be noted that the contour of the top side of the stopper portion 60 of the plunger 80 is formed to be substantially consistent with the contour of the inner surface near the location where the accommodating space 75 and the flow path 76 connect (the deepest part of the accommodating space 75). As a result, when the plunger 80 slides during injection and reaches the deepest part of the accommodating space 75, the gap formed between the stopper portion 60 and the inner surface of the container 70 can be minimized, thereby preventing the injection from remaining in the accommodating space 75 and being wasted. However, the shape of the stopper portion 60 is not limited to a specific shape as long as it can achieve the desired effect in the syringe 1 of this embodiment.

[0051] Among them, in the syringe 1, an igniter 22 is used as a pressure source for injecting the injection liquid. Therefore, when the igniter 22 is activated, a large pressure instantly acts on the inner wall of the combustion chamber 20a exposed to the combustion products and the inner wall of the internal space 36 pushed by the piston 40. Inside the syringe body 30, when viewed from the axial direction of the syringe 1, the piston 40 is movably arranged, but since there is no movable component in its radial direction, as the pressure rises, corresponding stress acts on the inside of the syringe body 30. Therefore, in order to suppress deformation or damage of the syringe body 30, a cylindrical reinforcement member 35 formed by a metal member is arranged inside the syringe body 30. As the metal material, for example, aluminum, iron, copper, steel or their alloys can be used. In the present disclosure, the reinforcement member 35 has a cylindrical shape, but other cylindrical forms can also be used.

[0052] like Figure 1 As shown, in the syringe body 30, the portion where the reinforcing member 35 surrounds the igniter 22 and the combustion chamber 20a, that is, the portion that includes the igniter 22 and the combustion chamber 20a disposed inside the reinforcing member 35 when the syringe body 30 is cut in the radial direction, is defined as the first portion 30a. Furthermore, in the syringe body 30, the portion where the reinforcing member 35 surrounds the internal space 36, that is, the portion that includes the internal space 36 disposed inside the reinforcing member 35 when the syringe body 30 is cut in the radial direction, is defined as the second portion 30b. Furthermore, the reinforcing member 35 is formed so as to extend across the first portion 30a and the second portion 30b along the axial direction of the syringe 1.

[0053] and, Figure 2AA cross-sectional view of the syringe 1 taken along line AA showing the first portion 30a is shown. Figure 2B The BB cross-sectional view of the syringe 1 at the second portion 30b is shown. Figure 2A and Figure 2B As can be understood from the figure, the syringe 1 is constructed such that the pressure generated by the combustion of the explosive powder in the igniter 22 is strongly applied to the radial inner wall of the syringe body 30 at the first and second locations 30a, 30b. This pressure is appropriately supported by the metal reinforcement member 35 at these first and second locations. Furthermore, because the metal reinforcement member 35 is clamped radially by the resin syringe body 30, the syringe body 30, constructed from a composite material of resin and metal, effectively enhances its strength against this pressure. Furthermore, the cylindrical shape of the reinforcement member 35 allows for uniform support of this pressure, further effectively improving the strength of the syringe body 30.

[0054] Furthermore, when a cylindrical metal member is used as the reinforcing member 35, the member is usually a "metal pipe", so it is extremely easy to obtain and process. That is, a ready-made metal pipe having a diameter size that accommodates the igniter 22 and the combustion chamber 20a is prepared, and it is cut according to the axial length of the first part 30a and the second part 30b, thereby making it easy to form the reinforcing member 35. Moreover, in the manufacturing process of the syringe 1, in a state where the reinforcing member 35 is arranged at a specific position in the mold for forming the syringe body 30, a specific resin material is injected into the mold for insert molding, thereby making it possible to form Figure 1 The syringe body 30 is shown. At this time, the igniter 22 can also be insert-molded together.

[0055] in this way, Figure 1 The illustrated syringe 1 employs a structure in which a metal reinforcing member 35 is embedded within a resin syringe body 30. This structure allows for effective protection of the syringe body 30 against the pressure exerted by the activation of the igniter 22. In particular, since the syringe body 30 is effectively strengthened by combining resin and metal, the proportion of metal in the syringe body 30 can be reduced, enabling a more compact and lightweight syringe 1 and preventing degradation in user operability. Furthermore, as described above, the syringe 1 can be manufactured simply, significantly reducing the manufacturing cost.

[0056] <Modification>

[0057] Combined with the reinforcing member 35 in the syringe 1 disclosed in this application, based on Figure 3 A modification of this embodiment will be described. Figure 3In the syringe 1 shown, the reinforcing member 35 extends only in the first portion 30a of the syringe body 30. The radial thickness of the syringe body 30 at the second portion 30b is thicker than the radial thickness of the syringe body 30 at the first portion 30a. In addition, since the piston 40 pushes the internal space 36 in the second portion 30b, the pressure rise rate in the internal space 36 can be smoothed compared to the pressure in the combustion chamber 20a at the initial stage of the igniter 22. Therefore, it is relatively easy to ensure the strength of the second portion 30b to cope with the pressure. Therefore, in the case where the strength of the second portion 30b can be sufficiently ensured, as Figure 3 As shown, the length of the reinforcing member 35 may be set to a length extending only in the first portion 30 a .

[0058] <Second embodiment>

[0059] based on Figure 4 A second embodiment of the syringe 1 of the present disclosure will be described. Figure 4 is with Figure 1 Similarly, the diagram showing the schematic structure of the syringe 1 is Figure 4 The structure shown in Figure 1 Substantially the same structures as shown are given the same reference numerals, and detailed description thereof is omitted.

[0060] Figure 4 The reinforcing member 35 in the illustrated syringe 1 is formed by laminating two sub-members 35a and 35b. Both sub-members 35a and 35b are cylindrical members formed from a metal material (e.g., aluminum, iron, copper, steel, or alloys thereof). Furthermore, the inner diameter of sub-member 35a is equal to or greater than the outer diameter of sub-member 35b, and the interior space of sub-member 35a can accommodate sub-member 35b in a laminated manner. Furthermore, sub-member 35a has an axial length extending between the first portion 30a and the second portion 30b of the syringe body 30, while sub-member 35b has an axial length extending only within the first portion 30a of the syringe body 30.

[0061] As described above, it is easier to ensure the strength of the second portion 30b against the pressure generated by the starter igniter 22 than the first portion 30a. Therefore, the first portion 30a and the second portion 30b of the syringe body 30 each require different minimum reinforcement levels. As described above, by stacking sub-components of different diameters to form a reinforcing member 35 that provides the required strength to each portion, the amount of metal required to reinforce the entire syringe 1 can be minimized. As a result, the syringe 1 can be made smaller and lighter. Furthermore, since the reinforcing member 35 can be formed by stacking cylindrical metal tubes as the sub-components 35a and 35b, it can be easily manufactured, and the manufacturing cost of the syringe 1 can be kept low.

[0062] In addition, Figure 4 In the example shown, the first portion 30a and the second portion 30b have different numbers of sub-component layers. However, if there is a region in the first portion 30a that needs to be further strengthened, for example, sub-components with different diameters can be prepared to increase the number of layers and thereby enhance the strength of that region. The same applies to the second portion 30b.

[0063] <Third embodiment>

[0064] based on Figure 5 and Figure 6 A third embodiment of the syringe 1 of the present disclosure will be described. Figure 5 is with Figure 1 Similarly, the diagram showing the schematic structure of the syringe 1 is Figure 5 The structure shown in Figure 1 The structures shown are substantially the same as those shown in the figure, and the same reference numerals are given to omit their detailed descriptions. Figure 6 Is for assembly Figure 5 The sequence of the syringe 1 is shown in FIG.

[0065] Figure 5 and Figure 6 The reinforcing member 35 in the syringe 1 shown is Figure 1 The reinforcing member 35 of the syringe 1 shown is the same, and is a metal cylindrical member having a length extending from the first portion 30a and the second portion 30b inside the syringe body 30. Figure 6 As shown, the syringe body 30 is formed by screwing a first shell 31 provided with an igniter 22 and a second shell 32 equipped with a container 70 into one body. The first shell 31 is a female cylindrical shape, and the igniter 22 is located on the bottom surface of its internal space. In addition, the second shell 32 is a male shape that can be embedded in the internal space of the first shell 31. A space that becomes the combustion chamber 20a is formed on the base end side of the second shell 32 (the opposite side of the first shell 31). By combining the two, the syringe 1 becomes Figure 5 The structure shown. It should be noted that Figure 5 The structure of the syringe 1 shown is essentially the same except that the syringe body 30 is formed from two shells.

[0066] In the syringe 1 having this assembly structure, as Figure 6As shown in the figure, in a state where a cylindrical reinforcement member 35 is arranged on the surface of the inner space of the first shell 31, the second shell 32 is inserted into and screwed to the first shell 31. Therefore, a gap is formed between the first shell 31 and the second shell 32 to accommodate the reinforcement member 35. As a result of installing the two shells, the reinforcement member 35 is sandwiched between the first shell 31 and the second shell 32, which is substantially the same as Figure 1 Alternatively, in a state where the outer surface of the second housing 32 is provided with a cylindrical reinforcing member 35, the first housing 31 is embedded in and screwed into the second housing 32, thereby forming Figure 5 The syringe 1 is shown.

[0067] According to this embodiment, the arrangement of the reinforcing member 35 inside the syringe body 30 can be achieved by the assembly process of the two housings. Figure 1 In the embodiment shown, the reinforcing member 35 is disposed simultaneously with the syringe body 30 formed of a resin material, that is, insert molding is required. However, in this embodiment, the reinforcing member 35 can be disposed without insert molding. Therefore, the syringe 1 can be manufactured simply and its manufacturing cost can be reduced.

[0068] <Fourth embodiment>

[0069] based on Figure 7 A fourth embodiment of the syringe 1 of the present disclosure will be described. Figure 7 is with Figure 1 Similarly, the diagram showing the schematic structure of the syringe 1 is Figure 7 The structure shown in Figure 1 Substantially the same structures as shown are given the same reference numerals, and detailed description thereof is omitted.

[0070] Figure 7 The reinforcing member 35 of the syringe 1 shown is Figure 1 The reinforcing member 35 of the syringe 1 shown is the same, and is a metal cylindrical member having a length extending from the first portion 30a to the second portion 30b inside the syringe body 30. Figure 7 In the illustrated syringe 1, as a further additional reinforcement member, a reinforcement member 350 is provided on the surface of the syringe body 30 that defines the internal space 36, forming a sliding surface for the piston 40. Reinforcement member 350 is formed from the same metal member as reinforcement member 35. Reinforcement member 350 is a cylindrical member that defines the space that becomes the internal space 36. An opening 351 is formed at its top end, through which the piston 40 can pass. This opening 351 communicates with the internal space 37. Because the diameter of opening 351 is smaller than the flange surface 41 of the piston 40, the opening 351 prevents the piston 40 from advancing.

[0071] By providing the additional reinforcing member 350, the second portion 30b can be strengthened against the pressure generated when the igniter 22 is activated. Furthermore, by using a metal surface as the sliding surface of the piston 40, the friction acting on the piston 40 can be reduced, allowing for more efficient injection of the injection solution. Furthermore, since the metal reinforcing member 350 receives and blocks the advancement of the piston 40, the metal member absorbs the impact generated during this process, thereby preventing deformation or damage to the syringe body 30.

[0072] The various solutions disclosed in the specification of this application may be combined with any other features disclosed in the specification.

[0073] Description of Reference Numerals

[0074] 1: Syringe (needle-free syringe)

[0075] 22: Ignition

[0076] 30: Syringe body

[0077] 30a: First part

[0078] 30b: Second part

[0079] 31: First shell

[0080] 32: Second shell

[0081] 35: Reinforcement

[0082] 350: Reinforcement

[0083] 351: Opening

[0084] 40: Piston

[0085] 70: Container

[0086] 71: Container support

[0087] 75: Accommodation space

[0088] 76: Flow path

[0089] 77: Ejection port

[0090] 80: Plunger

Claims

1. A needle-free injector for injecting a target substance into a target area without using an injection needle, comprising: a syringe body formed of a resin member; an igniter, which is provided in the injector body and releases injection energy for injecting the injection target substance into the combustion chamber in the injector body by burning ignition powder; a receiving portion, which is provided on the syringe body, has a receiving space for receiving the injection target substance and defines a flow path so that the injection target substance is injected from the ejection port into the target area; as well as a piston configured to advance in a passage in the syringe body communicating with the combustion chamber using the injection energy so as to pressurize the injection target substance accommodated in the accommodation space, A reinforcing member is provided inside the syringe body. The reinforcing member is a tubular member formed by a metal member and surrounds at least the igniter and the combustion chamber and extends along the axial direction of the syringe body. The reinforcing member is arranged in a radial direction of the syringe body in a state of being clamped by the syringe body.

2. The needle-free injector according to claim 1, wherein The reinforcing member surrounds not only the igniter and the combustion chamber but also at least a portion of the passage and extends in the axial direction of the injector body.

3. The needle-free injector according to claim 2, wherein: In the injector body, a thickness of the injector body forming the combustion chamber is set to be thinner than a thickness of the injector body forming the passage; In the reinforcing member, a first portion surrounding the igniter and the combustion chamber is set to have a thickness greater than a second portion surrounding the passage.

4. The needle-free injector according to claim 3, wherein The reinforcing member is formed by laminating a plurality of metal cylindrical sub-members having different diameters, and the number of laminated sub-members corresponding to the first portion is greater than the number of laminated sub-members corresponding to the second portion.

5. The needle-free injector according to any one of claims 1 to 4, wherein The injector body includes a first housing provided with the igniter and a second housing provided with the accommodating portion. In a state where the reinforcing member is arranged on the surface of the first shell, or in a state where the reinforcing member is arranged on the surface of the second shell, the first shell and the second shell are mounted to each other, so that the reinforcing member is clamped by the first shell and the second shell.

6. The needle-free injector according to any one of claims 1 to 4, wherein A sliding surface of the piston is formed on a surface of the syringe body forming the passage, and a cylindrical additional reinforcement member formed of a metal member is provided.

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