Needleless injector body and needleless injector

Abstract

The invention provides a needleless syringe body and a needleless syringe. The actuation mechanism of the needleless injector body includes: a locking sleeve disposed adjacent to the pushrod assembly and configured to lock the pushrod assembly; the releasing device is arranged adjacent to the locking sleeve and is used for releasing the push rod assembly; a retaining spring for biasing the locking sleeve and the release device in a direction away from each other; in the non-actuating state, the push rod assembly is blocked by the locking sleeve and cannot move forwards; when entering an actuated state during use, the locking sleeve and the release device are close to each other against the acting force of the retaining spring, so that the push rod assembly is released, and the push rod assembly is allowed to move from the non-actuated position to the actuated position.

Description

Technical Field

[0001] This invention relates to a medical device for injecting a substance. More specifically, this invention relates to a needleless injector body and a needleless injector. Background Technology

[0002] Prefilled needle-free injectors are innovative medical devices that combine prefilled packaging technology and needle-free injection technology. They are mainly used for subcutaneous or intramuscular injection of drugs, especially biological agents, vaccines, insulin, etc.

[0003] Traditional injection methods include needle-based syringes, but these present problems such as needle phobia, needlestick injury risk, cross-infection, and medical waste disposal. Pre-filled syringes are also available on the market, which simplify the filling process but still rely on needle injection.

[0004] Needle-free injectors eliminate the need for needles. Instead, they are medical devices that inject medication into the patient's body by applying high pressure to the drug, causing a high-pressure jet to penetrate the skin through micro-holes at the tip, thus avoiding the pain of needle pricks. However, traditional needle-free injectors typically require manual filling of the medication, which is cumbersome and prone to contamination. Specifically, a traditional needle-free injector may include an injection head and a body. The injection head and a reservoir, such as a cartridge, are housed within the body of the injector. The injection head draws the medication from the reservoir within the body. After drawing the medication, the injection head is actuated to deliver the injection.

[0005] There is an urgent market demand for pre-filled needleless injectors that combine pre-filling and needleless injection. Therefore, there is a need to provide a needleless injector body and a needleless injector to at least partially address the aforementioned problems or at least partially achieve the aforementioned objectives. Summary of the Invention

[0006] According to one aspect of the present invention, a needle-free injector body is provided, comprising: a base; a housing connected to the base and defining a receiving space; a plunger assembly disposed adjacent to the base in the receiving space; and an actuation mechanism configured to lock the plunger assembly in a non-actuated position in a non-actuated state and actuate the plunger assembly in an actuated state to achieve injection, wherein the actuation mechanism includes: a locking sleeve disposed adjacent to the plunger assembly and used to lock the plunger assembly; a release device disposed adjacent to the locking sleeve and used to release the plunger assembly; and a retaining spring for biasing the locking sleeve and the release device toward a direction away from each other; in the non-actuated state, the plunger assembly is blocked by the locking sleeve and cannot move forward; when entering the actuated state during use, the locking sleeve and the release device move closer to each other against the force of the retaining spring, causing the plunger assembly to be released, thereby allowing the plunger assembly to move from the non-actuated position to the actuated position.

[0007] In one embodiment, the push rod assembly has a stop groove near the front end of the housing; a locking sleeve is fixedly connected to the base and sleeved between the base and the push rod assembly, and has at least one through hole on its outer peripheral surface; the release device includes a release sleeve sleeved on the locking sleeve and movable along the outer surface of the locking sleeve, and has a release groove on its inner peripheral surface; a retaining spring is disposed between the release sleeve and the base; in the locked state, the stop groove is aligned with the at least one through hole, and at least one stop is disposed in the stop groove and the at least one through hole and blocked by the release sleeve; when entering the actuated state during use, the release sleeve moves toward the base against the action of the retaining spring until the release groove is aligned with the at least one through hole, causing the push rod assembly to push the at least one stop into the release groove, thereby allowing the push rod assembly to move from the non-actuated position to the actuated position.

[0008] In one embodiment, the push rod assembly includes a push rod and a push rod spring, the push rod spring being disposed inside the push rod and between the closed front end of the push rod and the base, and the stop groove being disposed on the outer peripheral surface of the push rod.

[0009] In one embodiment, the push rod assembly includes a push rod and pressurized gas sealed inside the push rod, with a first sealing ring provided at the front end of the push rod and a second sealing ring provided at a distance from the rear side of the first sealing ring, such that the pressurized gas is sealed between the first sealing ring and the second sealing ring.

[0010] In one embodiment, the actuation mechanism further includes an actuation sleeve disposed at the front end of the release sleeve for pushing the release sleeve toward the base.

[0011] In one embodiment, the housing includes a first housing segment and a second housing segment, the second housing segment being located between the first housing segment and the base.

[0012] In one embodiment, the first housing segment and the second housing segment are connected to the base by threads.

[0013] In one embodiment, the inner circumferential surface of the second housing segment is provided with a stop shoulder, and the front end face of the release sleeve abuts against the stop shoulder.

[0014] In one embodiment, a positioning shoulder is provided on the inner peripheral surface of the first housing segment, and the front end face of the actuating sleeve abuts against the positioning shoulder.

[0015] In one embodiment, the locking sleeve is connected to the internal thread of the base via an external thread.

[0016] In one embodiment, the locking sleeve is provided with an annular flange, and the retaining spring is disposed between the release sleeve and the annular flange.

[0017] In one embodiment, a base shoulder is provided on the inner peripheral surface of the base, and the base shoulder is aligned with the annular flange.

[0018] In one embodiment, the outer peripheral surface of the release sleeve is provided with a safety groove, and the second housing section is provided with a safety insertion hole.

[0019] In one embodiment, in the locked state, the safety slot is aligned with the safety socket, and the safety locking member passes through the safety socket and enters the safety slot.

[0020] In one embodiment, the stop is selected from the group consisting of: a ball, a needle roller, a roller, a wedge, and a slider.

[0021] In one embodiment, the push rod assembly has a recess, a locking sleeve is fitted onto the push rod assembly and has at least one through hole on its outer peripheral surface, and a release device includes a release sleeve fitted onto the rear end of the locking sleeve and having a release groove on its inner peripheral surface; in the non-actuated state, the recess is aligned with the at least one through hole, and at least one stop is disposed in the recess and the at least one through hole and blocked by the release sleeve; when entering the actuated state during use, the retaining spring is compressed, and the locking sleeve moves toward the base until the release groove is aligned with the at least one through hole, causing the push rod assembly to push the at least one stop into the release groove, thereby allowing the push rod assembly to move from the non-actuated position to the actuated position.

[0022] In one embodiment, the retaining spring is disposed around the locking sleeve and abuts against the housing back shoulder at one end of the housing; when the actuation state is entered during use, the retaining spring is compressed against the housing back shoulder, and the locking sleeve moves toward the base until the release groove is aligned with the at least one through hole, causing the push rod assembly to push the at least one stop into the release groove, thereby allowing the push rod assembly to move from the non-actuated position to the actuated position.

[0023] In one embodiment, the recess is an annular shape or a rectangular groove.

[0024] In one embodiment, the release sleeve is fixedly connected to the base or formed as an integral structure.

[0025] In one embodiment, the stop is selected from the group consisting of: ball, needle roller, roller, wedge, and slider.

[0026] In one embodiment, the push rod assembly includes a push rod and a pressurized gas sealed around the push rod, a push rod flange is provided at the front end of the push rod, a recess is provided on the outer peripheral surface of the rear end of the push rod, and a first sealing ring is provided on the rear side of the push rod flange.

[0027] In one embodiment, the push rod assembly includes a push rod and a push rod spring, the push rod spring being sleeved on the push rod, a push rod flange being provided at the front end of the push rod, the front end of the push rod spring abutting against the push rod flange, and a recess being provided on the outer peripheral surface of the rear end of the push rod.

[0028] In one embodiment, the actuation mechanism further includes an actuation sleeve disposed at the front end of the locking sleeve for pushing the locking sleeve toward the base.

[0029] In one embodiment, the rear end of the push rod spring abuts against the front end face of the actuating sleeve.

[0030] In one embodiment, a second sealing ring is provided at the front end face of the actuating sleeve, so that the pressurized gas is sealed between the first sealing ring and the second sealing ring.

[0031] In one embodiment, the actuating sleeve includes a locking flange, and the front end of the retaining spring abuts against the locking flange, such that the retaining spring is disposed between the actuating sleeve and the back shoulder of the housing.

[0032] In one embodiment, the needleless injector body further includes an auxiliary sleeve disposed inside the housing and sleeved outside the actuation sleeve, the rear end of the auxiliary sleeve abutting against the locking flange and the front end abutting against the front shoulder of the housing.

[0033] In one embodiment, the needleless injector body further includes an auxiliary sleeve disposed inside the housing and sleeved outside the actuating sleeve, wherein the front end of the retaining spring abuts against the rear end of the auxiliary sleeve, such that the retaining spring is disposed between the auxiliary sleeve and the rear shoulder of the housing.

[0034] In one embodiment, the locking sleeve is provided with a positioning flange, one end of the retaining spring abuts against the positioning flange, and the other end abuts against the housing back shoulder or the release sleeve, such that the retaining spring is disposed between the locking sleeve and the housing back shoulder or the release sleeve.

[0035] In one embodiment, the needleless injector body further includes an auxiliary sleeve disposed inside the housing and sleeved outside the actuating sleeve. The housing is provided with an auxiliary sleeve stop shoulder, such that the rear end of the auxiliary sleeve abuts against the auxiliary sleeve stop shoulder in the actuated state, and the front end of the auxiliary sleeve abuts against the front shoulder of the housing in the non-actuated state.

[0036] In one embodiment, the auxiliary sleeve, the actuating sleeve, and the locking sleeve are an integral structure or fixedly connected together.

[0037] In one embodiment, the front end of the release sleeve is provided with a locking inner peripheral surface, which is aligned with the at least one through hole in the locked state.

[0038] In one embodiment, the front end of the release sleeve is a conical truncated platform, and the locking inner peripheral surface is the inner peripheral surface of the conical truncated platform.

[0039] In one embodiment, the needleless injector body further includes: a stop member adjusting sleeve disposed within the locking sleeve and having a rear end flange, the rear end flange being blocked outside the rear end of the locking sleeve and abutting against a pre-tightening spring, the pre-tightening spring being disposed between the stop member adjusting sleeve and the base.

[0040] In one embodiment, the locking sleeve is provided with a positioning flange, and the rear end of the actuating sleeve abuts against the positioning flange.

[0041] In one embodiment, in the non-actuated state, the front end of the auxiliary sleeve abuts against the front shoulder of the housing, and the positioning flange is spaced apart from the rear shoulder of the housing.

[0042] In one embodiment, in the actuated state, the front end of the auxiliary sleeve moves away from the front shoulder of the housing, the positioning flange abuts against the rear shoulder of the housing, and the stop member adjusting sleeve blocks the at least one through hole.

[0043] In one embodiment, the locking sleeve is connected to the housing and sleeved outside the push rod assembly. The push rod assembly includes a first arm and a second arm spaced apart from each other. The rear ends of the first arm and the second arm are respectively provided with conical surfaces, and the front ends of the conical surfaces are provided with stop steps. The locking sleeve includes a through hole for the first arm and the second arm to pass through. The release device includes a release hole provided in the base. In the non-actuated state, the stop step abuts against the rear end face of the locking sleeve, and the push rod assembly is blocked by the locking sleeve. In the actuated state, the release hole applies an actuating force to the conical surface, causing the stop step to move away from the rear end face of the locking sleeve, thereby allowing the push rod assembly to move from the non-actuated position to the actuated position.

[0044] In one embodiment, the rear end of the locking sleeve is provided with a positioning shoulder, the through hole axially penetrates the positioning shoulder, and the front end of the retaining spring abuts against the rear end face of the locking sleeve.

[0045] In one embodiment, the push rod assembly includes a push rod and a push rod spring, the push rod spring being sleeved on the push rod, the front end of the push rod having a push rod flange, and the front end of the push rod spring abutting against the push rod flange and the rear end abutting against the positioning shoulder.

[0046] In one embodiment, the push rod assembly includes a push rod and a pressurized gas sealed around the push rod. The front end of the push rod is provided with a push rod flange, and a first sealing ring is provided on the rear side of the push rod flange. A second sealing ring is provided at intervals on the rear side of the first sealing ring, such that the pressurized gas is sealed between the first sealing ring and the second sealing ring.

[0047] In one embodiment, the first arm and the second arm are disposed at the rear end of the push rod.

[0048] In one embodiment, when the first arm and the second arm enter the through hole, the conical surface passes through the through hole, causing the first arm and the second arm to move closer to each other, and after the stop step passes through the through hole, the first arm and the second arm return to their original positions, causing the stop step to abut against the rear end face of the locking sleeve.

[0049] In one embodiment, in the actuated state, the locking sleeve moves toward the release hole, such that the first arm and the second arm enter the release hole, the release hole clamps the conical surface, such that the first arm and the second arm move toward each other, the stop step moves away from the rear end face of the locking sleeve, and the push rod moves away from the through hole, thereby allowing the push rod assembly to move from the non-actuated position to the actuated position.

[0050] According to another aspect of the present invention, a needleless injector is provided, comprising a needleless injector body as described above and an injection head mounted on the front end of the needleless injector body.

[0051] In one embodiment, the injection head includes a drug reservoir, a piston capable of pushing liquid medicine forward within the drug reservoir, and a piston rod connected to the piston.

[0052] In one embodiment, the piston and the piston rod are connected by a thread.

[0053] In one embodiment, the piston is bonded to the piston rod.

[0054] In one embodiment, the pistons are connected to each other via a flange.

[0055] In one embodiment, in the locked state, the piston rod is spaced a certain distance from the push rod assembly, and in the actuated state, the push rod assembly pushes the piston rod to move.

[0056] In one embodiment, the injection head further includes a drug reservoir support that surrounds the drug reservoir and supports it within the housing.

[0057] This invention provides a needleless injector body and a needleless injector, which have a simple actuation structure, low cost and easy implementation. Simply press the needleless injector toward the patient's skin to a certain pressure to automatically trigger the injection and drug delivery. Attached Figure Description

[0058] To better understand the above and other objects, features, advantages, and functions of the present invention, reference can be made to the preferred embodiments shown in the accompanying drawings. The same reference numerals in the drawings refer to the same parts. Those skilled in the art should understand that the drawings are intended to schematically illustrate preferred embodiments of the invention and do not limit the scope of the invention in any way; the parts in the drawings are not drawn to scale.

[0059] Figure 1 This is a perspective view of a needle-free injector according to an embodiment of the present invention.

[0060] Figure 2 This is a perspective view of a needle-free injector according to an embodiment of the present invention, wherein the injection head cap has been removed.

[0061] Figure 3 This is a perspective view of the first housing segment according to an embodiment of the present invention.

[0062] Figure 4 This is a perspective view of the second housing segment according to an embodiment of the present invention.

[0063] Figure 5 This is another perspective view of the second housing segment according to one embodiment of the present invention.

[0064] Figure 6 This is an exploded view of a needle-free injector according to one embodiment of the present invention.

[0065] Figure 7 This is a perspective view of the injection head and actuation structure of a needleless injector according to an embodiment of the present invention.

[0066] Figure 8 This is a perspective view of a base according to one embodiment of the present invention.

[0067] Figure 9 This is an exploded view of the actuation structure of a needleless injector according to an embodiment of the present invention.

[0068] Figure 10 This is a perspective view of the release sleeve of a needleless injector according to an embodiment of the present invention.

[0069] Figure 11 This is a perspective view of the actuation structure of a needleless injector according to an embodiment of the present invention, including a retaining spring, a locking sleeve, and a push rod assembly.

[0070] Figure 12 This is a perspective view of a locking sleeve and push rod assembly of a needleless injector according to an embodiment of the present invention.

[0071] Figure 13This is a cross-sectional view of a needleless injector in a locked state according to an embodiment of the present invention.

[0072] Figure 14 This is a cross-sectional view of a needleless injector in an actuated state according to an embodiment of the present invention.

[0073] Figure 15 This is a perspective view of a needle-free injector according to another embodiment of the present invention.

[0074] Figure 16 This is a perspective view of a needle-free injector according to another embodiment of the present invention, wherein half of the housing and base have been removed.

[0075] Figure 17 This is a perspective view of a needleless injector according to another embodiment of the present invention, wherein the housing and base have been removed and an auxiliary sleeve is shown.

[0076] Figure 18 This is a perspective view of a needleless injector according to another embodiment of the present invention, showing a push rod assembly, an actuating sleeve, a locking sleeve, and a release sleeve.

[0077] Figure 19 This is an exploded view of a needleless injector according to another embodiment of the present invention, showing the plunger assembly, locking sleeve, and release sleeve.

[0078] Figure 20 This is a cross-sectional view of a needleless injector in a locked state according to another embodiment of the present invention.

[0079] Figure 21 This is a cross-sectional view of a needleless injector in a critical state according to another embodiment of the present invention.

[0080] Figure 22 This is a cross-sectional view of a needleless injector in an actuated state according to another embodiment of the present invention.

[0081] Figure 23 This is a perspective view of a needle-free injector according to yet another embodiment of the present invention.

[0082] Figure 24 This is an exploded view of a needle-free injector according to yet another embodiment of the present invention.

[0083] Figure 25 This is a cross-sectional view of a needleless injector in a locked state according to another embodiment of the present invention.

[0084] Figure 26 This is a cross-sectional view of a needleless injector in a critical state according to another embodiment of the present invention.

[0085] Figure 27 This is a cross-sectional view of a needleless injector in an actuated state according to another embodiment of the present invention. Detailed Implementation

[0086] Now, with reference to the accompanying drawings, specific embodiments of the present invention will be described in detail. The embodiments described herein are merely preferred embodiments of the invention; those skilled in the art can conceive of other ways to implement the invention based on these preferred embodiments, and such other ways also fall within the scope of the invention.

[0087] First, it should be noted that the "axial direction" or "longitudinal direction" mentioned in this article can be understood as the direction of the axis of the needle-free injector. In this axial direction, the direction towards the patient's medication site when using the needle-free injector is called the "front side", and the opposite direction is called the "back side".

[0088] It should be noted that this article uses drugs, pharmaceuticals, and liquid drugs as examples to describe the concept of this disclosure, but this is only an example and is not restrictive. The injectable substance can be of various other types, such as saline, glucose, biological agents, vaccines, insulin, etc. As long as it can be injected into a living organism (e.g., a human, animal, etc.) by the needle-free injector of this disclosure, it falls within the protection scope of this disclosure.

[0089] This article uses a pre-filled needle-free injector as an example to describe the actuation mechanism for needle-free injectors. However, this is only an example, and the actuation mechanism described herein can also be used in ordinary needle-free injectors. The pre-filled needle-free injector has a drug reservoir directly installed inside. The piston inside the reservoir is directly connected to the plunger assembly of the needle-free injector via a piston rod. Therefore, the actuation mechanism of the needle-free injector can directly actuate the plunger assembly, which in turn pushes the piston rod and piston to move within the reservoir, thereby injecting the drug into the body. The pre-filled needle-free injector pre-fills a fixed amount of medication, such as a single dose, directly into the reservoir at the manufacturing stage (e.g., at the pharmaceutical factory), eliminating the need for patients to manually fill the reservoir and inject the required amount. This eliminates the need for subsequent aspiration or filling steps, allowing for direct injection and avoiding problems such as contamination or dosage errors caused by pre-filling or aspiration procedures. Prefilled needle-free injectors are convenient and quick to use, enabling precise drug delivery. Patients can open and use them immediately upon receiving them, making them suitable for emergency situations or home self-administration, such as insulin injections for diabetic patients.

[0090] This article describes an actuation mechanism with two states: a non-actuated state (or locked state) and an actuated state (or released state). In the non-actuated state, the actuation mechanism can hold the push rod assembly in the locked state, preventing the push rod assembly from pushing the piston in the drug reservoir to perform an injection operation. In the released state, the actuation mechanism can trigger or actuate the push rod assembly to push the piston in the drug reservoir to perform an injection operation, thereby injecting the drug solution in the drug reservoir into the patient.

[0091] Figures 1 to 2 A needle-free injector 1000 according to an embodiment of the present invention is shown, comprising a needle-free injector body and an injection head mounted on the front end of the needle-free injector body. Reference Figure 13 and Figure 14 The injection head includes a drug reservoir 10, a piston 11 capable of pushing the drug liquid forward within the drug reservoir 10, and a piston rod 12 connected to the piston. The drug reservoir 10 has an injection micro-hole at its front end, and the injection head has a cap 140 to close the injection micro-hole.

[0092] See Figure 13-14 The piston 11 and piston rod 12 can be connected in any way, such as by threaded connection, adhesive bonding, or flange connection, as long as they are fixedly connected together. Alternatively, since the drug reservoir is disposable, the piston only needs to perform one injection operation. Therefore, the piston 11 and piston rod 12 can be separate, as long as the piston rod 12 can push the piston 11 to move during injection.

[0093] The needle-free injector body includes a housing, a base 130, and a plunger assembly. The housing includes a first housing segment 110 and a second housing segment 120, which are threaded together with the base 130, wherein the second housing segment 120 is located between the first housing segment 110 and the base 130. The base 130 has a forward opening and forms a receiving space with the housing. The first housing segment 110 is provided with a front opening for securely mounting the injection head.

[0094] The drug reservoir 10 and the push rod assembly are located within the receiving space. The piston 12 inside the drug reservoir is driven by the push rod assembly to inject the liquid medication forward. The injection head also includes a drug reservoir support 20, through which the drug reservoir 10 is supported within the housing and held by the housing. The drug reservoir support surrounds the drug reservoir, and the two are tightly fitted, for example, with an interference fit. The drug reservoir support protects the drug reservoir from damage during transportation or in case of accidents.

[0095] The push rod assembly includes a push rod 500 and a push rod spring 600. The push rod 500 is hollow inside, closed at the front end, and open at the rear end. The push rod spring 600 is located inside the push rod 500 and between the closed front end of the push rod 500 and the base 130.

[0096] Alternatively, compressed gas can be used instead of the push rod spring as the power source for the push rod. In this case, the push rod assembly includes a push rod and compressed gas sealed inside the push rod. Specifically, a first sealing ring is provided at the front end of the push rod, and a second sealing ring is provided at a distance from the rear side of the first sealing ring, such that the compressed gas is sealed between the first and second sealing rings. The compressed gas refers to a compressed gas, such as air, nitrogen, carbon dioxide, etc. When the push rod is actuated, the compressed gas pushes the push rod forward, thereby driving the piston. The second sealing ring can be provided at any suitable position behind the first sealing ring, and the position does not affect or interfere with the operation of the actuation mechanism. For example, the second sealing ring can be positioned against the inner rear end face of the base 130, and the second sealing ring can be provided at any other suitable position, as long as a closed space is formed between the first and second sealing rings to accommodate the compressed gas, all of which fall within the protection scope of this disclosure.

[0097] A stop groove 501 is provided on the outer surface of the front end of the push rod 500, and at least one stop member 700 is disposed in the stop groove 501. The stop member can be, for example, a ball, needle roller, roller, wedge, slider, etc., and there are no restrictions on its shape and type, as long as it can stop the push rod assembly, it falls within the protection scope of this disclosure. Correspondingly, there are no restrictions on the shape and number of stop grooves 501, as long as they can receive the stop member. For example, the stop groove 501 can be an annular groove, a rectangular groove, a discrete groove, etc.

[0098] The actuation mechanism includes a locking sleeve 200 and a retaining spring 250. The locking sleeve 200 is connected to the internal thread 1310 of the base 130 via an external thread 210 at its rear end. The locking sleeve 200 has an annular flange 201 adjacent to the external thread 210 at its rear end, which is used to position the retaining spring 250, as will be described below. The locking sleeve 200 has at least one through hole 202 at its front end, radially penetrating the wall of the locking sleeve 200 in the circumferential direction, for receiving at least one stop 700 and allowing the stop 700 to pass freely.

[0099] In the assembled state, such as Figure 9 , Figure 11 , Figure 13As shown, the locking sleeve 200 is fixedly connected to the base 130. The push rod assembly is disposed inside the locking sleeve 200. The stop groove 501 of the push rod 500 is aligned with the through hole 202 of the locking sleeve 200. The stop member 700 is disposed within the stop groove 501 and the through hole 202. The rear end of the retaining spring 250 is positioned against the annular flange 201. In addition, a base shoulder 1301 is provided on the inner circumferential surface of the base 130. The base shoulder 1301 is aligned with the annular flange 201, so that the rear end of the retaining spring 250 can also simultaneously abut against both the annular flange 201 and the base shoulder 1301.

[0100] The actuation mechanism also includes a release sleeve 300 and an actuation sleeve 400. The release sleeve 300 is sleeved on the locking sleeve 200, disposed within the second housing section 120, and can slide along the outer surface of the locking sleeve 200 within the second housing section 120. An annular release groove 301 is provided on the inner circumferential surface of the front end of the release sleeve 300 for receiving the stop member 700 in the released state. An annular safety groove 302 is also provided on the outer circumferential surface of the release sleeve 300, corresponding to... Figure 4 As shown, the second housing segment 120 is provided with a safety insertion hole 1210 that radially penetrates the wall of the second housing segment 120. In the assembled state, the safety groove 302 is aligned with the safety insertion hole 1210, and the safety locking member passes through the safety insertion hole 1210 and enters the safety groove 302, preventing the release sleeve 300 from moving freely and preventing accidental triggering of the release sleeve 300 in the assembled state. The safety locking member can be any suitable component, such as a pin, plug, rod, etc. The inner circumferential surface of the second housing segment 120 can be provided with a stop shoulder 1201, and the front end face of the release sleeve 300 can abut against the stop shoulder 1201. The front end of the retaining spring 250 abuts against the rear end face of the release sleeve 300.

[0101] An actuating sleeve 400 is disposed at the front end of the release sleeve 300 and is used to apply actuating force to the release sleeve 300 during actuation. Specifically, the rear end face of the actuating sleeve 400 abuts against the front end face of the release sleeve 300. A positioning shoulder 1101 is provided in the inner peripheral surface of the first housing section 110, and the front end face of the actuating sleeve 400 abuts against the positioning shoulder 1101.

[0102] The following describes two states of the needle-free injector. The pre-drug administration state, also known as the inactive state, locked state, or initial state, is described below. Figure 13The medicine bottle 10 is supported in the housing by the medicine bottle bracket 20 and held by the housing. The rear end of the piston rod 12 is spaced a certain distance from the front end of the push rod 500. The medicine bottle bracket abuts against the front end of the actuating sleeve 400, the front end of the actuating sleeve 400 abuts against the positioning shoulder 1101, and the rear end abuts against the release sleeve 300. The front end of the release sleeve 300 abuts against the stop shoulder 1201. The front end of the retaining spring 250 abuts against the rear end of the release sleeve 300, and the rear end abuts against the annular flange 201 and the base shoulder 1301. The locking sleeve 200 is connected to the base 130. The stop groove 501 of the push rod 500 is aligned with the through hole 202 of the locking sleeve 200, and the stop 700 is disposed in the stop groove 501 and the through hole 202 to lock the push rod 500 in place. At this time, the push rod spring 600 is in a compressed state, compressed between the closed front end of the push rod 500 and the base 130. In the case of pressurized gas, the pressurized gas is sealed between the first sealing ring and the second sealing ring at the closed front end of the push rod 500, and for example, the second sealing ring can be located at the inner rear end face of the base 130, thus the pressurized gas is sealed between the closed front end of the push rod 500 and the base 130. In this state, the push rod assembly is locked, and the piston and piston rod of the medicine bottle cannot be pushed forward. To prevent accidental triggering, as mentioned above, the safety locking member passes through the safety socket 1210 into the safety groove 302, preventing the release sleeve 300 from moving freely.

[0103] See Figure 14When injection is required, the cap 140 is removed, and the front end of the reservoir 10 is pressed against the patient's skin to apply pressure. The skin exerts a counterforce on the reservoir 10, causing the reservoir 10 and reservoir holder 20 to move towards the base 130. Simultaneously, the piston rod 12 moves towards the base 130 and the front end face of the push rod 500, reducing the distance between it and the front end face of the push rod 500. The reservoir holder 20 pushes the actuating sleeve 400 backward, causing the actuating sleeve 400 to push the release sleeve 300 towards the base 130, while the spring 250 is compressed by the release sleeve 300. When the release sleeve 300 moves backward until its release groove 301 aligns with the through hole 202 of the locking sleeve 200, the piston rod 12 contacts the front end face of the push rod 500. Because the push rod spring 600 is in a compressed state, it exerts a forward thrust on the push rod 500, pushing it forward and driving the stop 700 from the through hole 202 into the release groove 301. In the case of pressurized gas, the pressurized gas expands and pushes the push rod 500, pushing the stop through the through hole into the release groove. At this time, the lock of the stop 700 on the push rod 500 is released, and the push rod 500 pushes the piston rod 12 forward to perform the injection operation, injecting the medication from the drug reservoir 10 into the patient. At this time, the needle-free injector is in the drug delivery state, also referred to as the actuated state, release state, unlocked state, or trigger state.

[0104] It is important to note that as the release sleeve 300 moves toward the base 130, the retaining spring 250 is compressed by the release sleeve 300 until the release groove 301 aligns with the through hole 202, meaning the retaining spring 250 is compressed to a certain amount or reaches a certain clamping force. This clamping force provides pressure feedback to the patient, allowing them to feel the entire process during drug administration. Furthermore, the retaining spring 250 provides pressure between the release sleeve 300 and the base and locking sleeve, requiring the release sleeve 300 to overcome the spring pressure during movement, thus preventing accidental triggering of the release sleeve 300. Moreover, this actuation mechanism allows for automatic drug administration simply by pressing the needle-free injector toward the patient's skin to a certain pressure.

[0105] The needleless injector and actuation mechanism of the second embodiment are described below. The needleless injector 2000 includes a needleless injector body and an injection head mounted on the front end of the needleless injector body.

[0106] The needle-free injector body includes a housing 2100, a base 2200, and a plunger assembly. The housing and base 2200 are fixedly connected together. The base 2200 has a forward opening and forms a receiving space with the housing. The housing has a front opening for securely mounting the injection head. The figure shows the housing and base 2200 as an integral structure, but this is only an example and not limiting. The housing and base 2200 can also be configured as separate units.

[0107] refer to Figures 20 to 22 The injection head includes a drug reservoir 10, a piston 11 capable of pushing the drug solution forward within the drug reservoir 10, and a piston rod 12 connected to the piston 11. The drug reservoir 10 has an injection micro-orifice at its front end, and a cap 2300 is provided on the injection head to seal the injection micro-orifice. The cap 2300 also serves to hold the injection head to the needle-free injector body, protecting the drug reservoir from damage during transportation or in case of accidents.

[0108] See Figures 20 to 22 The piston 11 and piston rod 12 can be connected in any way, such as by threaded connection, adhesive bonding, or flange connection, as long as they are fixedly connected together. Alternatively, since the drug reservoir is disposable, the piston only needs to perform one injection operation. Therefore, the piston 11 and piston rod 12 can be separate, as long as the piston rod 12 can push the piston 11 to move during injection.

[0109] The medicine bottle 10 and the push rod assembly are located within the receiving space. The piston 12 inside the medicine bottle is driven by the push rod assembly to inject the medicine liquid forward. The push rod assembly includes a push rod 2400 and a push rod spring 2500. The front end of the push rod 2400 has a push rod flange, and the front end of the push rod spring 2500 abuts against the push rod flange. A recess 2510 is provided on the outer surface of the rear end of the push rod 2400, and at least one stop 7000 is disposed in the recess 2510. Alternatively, a separate section of the push rod can be provided, with a recess on its outer surface, and this section of the push rod can be threaded to the push rod 2400. Similar to the first embodiment, the stop can be, for example, a ball, needle roller, roller, wedge, slider, etc., and its shape and type are not limited, as long as it can stop the push rod assembly, it falls within the protection scope of this disclosure. Correspondingly, the shape and number of the recess 2510 and the release groove described below are also not limited, as long as they can receive the stop. For example, the release groove and recess 2510 can be an annular groove, a rectangular groove, a discrete groove, etc.

[0110] Similarly, alternatively, pressurized gas can be used instead of the push rod spring as the power source for the push rod. In this case, the push rod assembly includes the push rod and pressurized gas sealed around the push rod. A first sealing ring is provided on the rear side of the push rod flange.

[0111] The actuation mechanism includes a locking sleeve 2600 and a retaining spring 2700. The locking sleeve 2600 has at least one through-hole 2610 radially penetrating its wall in the circumferential direction at its rear end. The through-hole 2610 accommodates at least one stop 7000 and allows the stop 7000 to pass freely. The locking sleeve 2600 has a locating flange 2620 in its intermediate section. The rear end of the retaining spring 2700 abuts against the housing rear shoulder 2110 of the housing 2100, and its front end abuts against the actuating sleeve, as will be described below.

[0112] The actuation mechanism also includes an actuating sleeve 2710 and a release sleeve 2800. The release sleeve 2800 is also a hollow cylindrical component with openings at both the front and rear ends to allow the locking sleeve 2600 to pass through and be fitted onto its rear end. The front end of the release sleeve 2800 is a necked conical truncated cone, the inner circumferential surface of which is called the locking inner circumferential surface, used to lock the stop 7000 in the locked state. Alternatively, the front end of the release sleeve 2800 can also be cylindrical, with the inner circumferential surface of the cylinder serving as the locking inner circumferential surface. An annular release groove is provided adjacent to the locking inner circumferential surface on the inner circumferential surface of the cylindrical main body of the release sleeve 2800, for receiving the stop 7000 in the released state. It should be noted that, for ease of description, the release sleeve 2800 is set and described separately in this embodiment. However, the release sleeve 2800 can be fixedly set in the base 2200 in various ways (e.g., threaded, bonded, etc.), or it can be formed as an integral structure with the base 2200, or the relevant features of the release sleeve 2800 can be machined in the base 2200 to realize the release function, such as setting a locking inner circumferential surface and a release groove in the base 2200.

[0113] The actuating sleeve 2710 can be connected to the locking sleeve 2600 via an internal thread, such that the rear end face of the actuating sleeve 2710 abuts against the positioning flange 2620 of the locking sleeve 2600. The actuating sleeve 2710 may be provided with a retaining flange 2720, which holds the front end of the retaining spring 2700 against the retaining flange 2720, thereby positioning it between the actuating sleeve 2710 and the housing back shoulder 2110 of the housing 2100. Figure 18 The diagram shows a gasket 2750 positioned on the front side of the actuating sleeve 2710. The gasket 2750 is smaller than the actuating sleeve 2710, facilitating the contact of the push rod spring 2500. However, this is merely an example; the gasket 2750 can be omitted, allowing the rear end of the push rod spring 2500 to directly abut against the front end face of the actuating sleeve 2710. In the case of pressurized gas, a second sealing ring can be provided at the front end face of the actuating sleeve, sealing the pressurized gas between the first and second sealing rings.

[0114] A preload spring 2910 can be installed inside the base 2200, with its rear end abutting against the inner rear end face of the base 2200.

[0115] The needle-free injector body also includes a stop and adjuster sleeve 2930. The stop and adjuster sleeve 2930 is disposed within the locking sleeve 2600, near the through hole 2610. The front end of the preload spring 2910 abuts against the rear flange of the stop and adjuster sleeve 2930, such that the preload spring 2910 is positioned between the stop and adjuster sleeve 2930 and the base 2200. The rear flange is larger than the locking sleeve 2600, thus preventing the rear flange of the stop and adjuster sleeve 2930 from being obstructed outside the locking sleeve 2600.

[0116] The needle-free injector body also includes an auxiliary sleeve 2770, which is positioned within the housing 2100. The front and rear ends of the auxiliary sleeve 2770 may be threaded, and the rear end of the drug reservoir 10 may also be threaded, allowing the front end of the auxiliary sleeve 2770 to be fixedly connected to the rear end of the drug reservoir 10 via threads. The outer surface of the actuating sleeve 2710 may be threaded, allowing the rear end of the auxiliary sleeve 2770 to be fixedly connected to the actuating sleeve 2710 via threads. Alternatively, the auxiliary sleeve, actuating sleeve, and locking sleeve may be fixedly connected together in other ways or may be a single integrated structure.

[0117] The following describes two states of the needle-free injector. The pre-drug administration state, also known as the inactive state, locked state, or initial state, is described below. Figure 20 The front end of the drug reservoir 10 is held to the needle-free injector body by a cap 2300, while the rear end is held in the housing by a fixed connection with an auxiliary sleeve 2770. The front end of the auxiliary sleeve 2770 abuts against the front shoulder of the housing, and the actuating sleeve and locking sleeve are also fixedly connected to the auxiliary sleeve 2770. A retaining spring 2700 is positioned between the actuating sleeve 2710 and the rear shoulder 2110 of the housing 2100, thereby keeping these components stationary and fixed; and the positioning flange 2620 of the locking sleeve 2600 is spaced apart from the rear shoulder 2110 of the housing. The front end face of the push rod contacts and holds the piston rod. A push rod spring is disposed between the push rod flange and the actuating sleeve. In the case of pressurized gas, the pressurized gas is sealed between a first sealing ring at the rear side of the push rod flange and a second sealing ring at the front end face of the actuating sleeve. The recess of the push rod aligns with the through hole of the locking sleeve. A stop, positioned within the recess and through hole and blocked and held in place by the locking inner circumferential surface, locks the push rod in place. The stop, along with the sleeve 2930, abuts against the rear end face of the push rod, thereby pushing the preload spring, which is then compressed. In this state, the push rod assembly is locked, preventing the piston and piston rod of the medicine bottle from being pushed forward.

[0118] See Figure 21 and Figure 22 When injection is required, the cap 2300 is removed, and the front end of the drug reservoir 10 is pressed against the patient's skin. Pressure is applied to the drug reservoir 10, and the skin exerts a counterforce on it, causing the drug reservoir 10 and the auxiliary sleeve 2770 to move towards the base 2200. This causes the actuating sleeve to move backward, compressing the retaining spring 2700 until the positioning flange 2620 of the locking sleeve 2600 abuts against the rear shoulder 2110 of the housing and cannot move further. At this time, the release groove aligns with the through hole, and the push rod spring pushes the push rod, pushing the stop into the release groove through the through hole. Under pressurized gas conditions, the pressurized gas expands and pushes the push rod, pushing the stop into the release groove through the through hole. At this time, the stop is released from locking the push rod, and the push rod pushes the piston forward to perform the injection operation, injecting the drug in the drug reservoir 10 into the patient's body. At this time, the needle-free injector is in the drug delivery state, also referred to as the critical state, actuation state, release state, unlocking state, or trigger state. That is, the actuation of the needleless injector in this embodiment requires pressing the injection head on the patient's skin at a certain distance and with a certain pressure to release the locked state.

[0119] It should be noted that as the locking sleeve moves toward the base 2200, the holding spring is compressed until the locking sleeve abuts against the rear shoulder of the housing, meaning the holding spring is compressed to a certain extent or reaches a certain clamping force. This clamping force provides pressure feedback to the patient, allowing the patient to feel the entire process during drug administration. Furthermore, the holding spring provides pressure between the base and the locking sleeve, requiring the locking sleeve to overcome the spring pressure during movement, thus preventing accidental triggering of the actuation mechanism.

[0120] It should be noted that, in another embodiment, the front end of the retaining spring 2700 can abut against the rear end of the auxiliary sleeve 2770, for example, when the actuating sleeve 2710 does not have the locking flange 2720, so that the retaining spring 2700 is positioned between the auxiliary sleeve 2770 and the housing rear shoulder 2110 of the housing, and its actuation process is similar to the above process, and will not be described again. To summarize the above scheme, the retaining spring 2700 is arranged around the locking sleeve 2600, and one end abuts against the housing rear shoulder of the housing, while the other end of the retaining spring abuts against the actuating sleeve or the auxiliary sleeve.

[0121] However, in other embodiments, the front end of the retaining spring can abut against the locking sleeve, that is, the front end of the retaining spring 2700 abuts against the positioning flange of the locking sleeve, and the rear end abuts against the rear shoulder of the housing, so that in the actuated state, the medicine bottle 10 and the auxiliary sleeve 2770 move toward the base 2200, thereby driving the actuating sleeve and the locking sleeve to move backward and compress the retaining spring 2700 until the release groove is aligned with the through hole, and the push rod pushes the stop into the release groove through the through hole.

[0122] In embodiments where the front end of the spring rests against the locking sleeve, the housing back shoulder 2110 may be omitted or retained. Additionally or optionally, an auxiliary sleeve stop shoulder is provided at a housing position in front of the housing back shoulder, such that the rear end of the auxiliary sleeve rests against the auxiliary sleeve stop shoulder in the actuated state, and the front end rests against the front shoulder of the housing in the non-actuated state. In this embodiment, in the locked state, the front end of the auxiliary sleeve 2770 rests against the front shoulder of the housing, keeping the spring 2700 positioned between the positioning flange of the locking sleeve and the housing back shoulder 2110 or the release sleeve 2800, thereby maintaining the stationary and fixed state of these components. The positioning flange 2620 of the locking sleeve 2600 is spaced apart from the housing back shoulder 2110, and the rear end of the auxiliary sleeve 2770 is spaced apart from the auxiliary sleeve stop shoulder. In the actuated state, the medicine bottle 10 and the auxiliary sleeve 2770 move toward the base 2200, so that the rear end of the auxiliary sleeve 2770 first abuts against the auxiliary sleeve stop shoulder and cannot move further. At this time, the release groove is aligned with the through hole, and the push rod pushes the stop into the release groove through the through hole.

[0123] Furthermore, as the stop enters the release groove and releases the lock on the push rod, the push rod moves forward. The stop adjustment sleeve 2930 abuts against the rear end face of the push rod and is thus pushed by the preload spring. Therefore, the stop adjustment sleeve 2930 moves forward along with the push rod, blocking the through hole and preventing the stop from subsequently falling into the locking sleeve through the through hole. This ensures the order and arrangement of the stops. The advantage of this is that after this triggering, when using the needle-free injector body again, simply resetting the push rod will lock the push rod again; thus ensuring the needle-free injector body can be reused.

[0124] The needleless injector and actuation mechanism according to the third embodiment are described below. The needleless injector 3000 includes a needleless injector body and an injection head mounted on the front end of the needleless injector body. Figure 23-27 The injection head has been omitted, so only the needleless injector body will be described below. Any of the aforementioned injection heads can be applied to this third embodiment.

[0125] The needle-free injector body includes a base 3100, a housing 3200, and a plunger assembly. The housing 3200 and the base 3100 are movable relative to each other. The base 3100 has a forward opening and forms a receiving space with the housing 3200. The housing is provided with a front opening for securely mounting the injection head.

[0126] The push rod assembly includes a push rod 3300 and a push rod spring 3400. The front end of the push rod has a push rod flange 3310, and the front end of the push rod spring 3400 abuts against the push rod flange 3310. The rear end of the push rod has a U-shaped fork arm, including a first arm 3320 and a second arm 3330 spaced apart from each other. These two arms are cantilevered for easy deformation. The rear ends of the two arms each have a conical or inclined surface 3340 to facilitate the clamping and application of force to the actuation button and to allow the first arm 3320 and the second arm 3330 to pass through the through hole 3520, as will be described below. The front end of the inclined surface 3340 has a stop step 3350. The stop step 3350 engages with the rear end face of the locking sleeve 3500, preventing the push rod from passing through the locking sleeve 3500 in a direction from rear to front.

[0127] Alternatively, pressurized gas can be used instead of the push rod spring as the power source for the push rod. In this case, the push rod assembly includes a push rod and pressurized gas sealed around the push rod. A first sealing ring is provided on the rear side of the push rod flange, and a second sealing ring is provided at a distance from the rear side of the first sealing ring, such that the pressurized gas is sealed between the first and second sealing rings. The second sealing ring can be positioned around the push rod at any suitable location, and its position will not affect or interfere with the operation of the actuation mechanism.

[0128] The actuation mechanism includes a locking sleeve 3500 and a retaining spring 3700. The locking sleeve 3500 can be fixedly connected to the housing 3200, for example, by threads. At the rear end of the locking sleeve 3500, an annular positioning shoulder 3510 and a through hole 3520 axially penetrating the positioning shoulder 3510 are provided. The rear end of the push rod spring 3400 abuts against the positioning shoulder 3510, and the through hole 3520 allows the first arm 3320 and the second arm 3330 to pass through.

[0129] The retaining spring 3700 is positioned between the rear end face of the locking sleeve 3500, opposite the positioning shoulder 3510, and the base 3100. The actuation mechanism also includes a release hole 3620 located on the inner rear end face of the base 3100 for clamping the inclined plane 3340, thereby deforming the first arm 3320 and the second arm 3330 to release the push rod.

[0130] The following describes two states of the needle-free injector. The pre-drug administration state, also known as the inactive state, locked state, or initial state, is described below. Figure 25When the first arm 3320 and the second arm 3330 of the push rod 3300 pass through the through hole 3520, their inclined surfaces 3340 first enter the through hole 3520 and are constrained by the through hole 3520, causing the first arm 3320 and the second arm 3330 to deform, that is, the first arm 3320 and the second arm 3330 move closer to each other. After passing through the through hole 3520, the first arm 3320 and the second arm 3330 return to their original shape, their inclined surfaces 3340 are spaced apart from the release hole 3620, and the stop step 3350 is locked onto the rear end face of the locking sleeve 3500. Although the push rod spring 3400 is in a compressed state and pushes the first arm 3320 and the second arm 3330 forward, the push rod 3300 is locked because the stop step 3350 of the first arm 3320 and the second arm 3330 is blocked by the rear end face of the locking sleeve 3500, and therefore, it cannot push the piston and piston rod of the medicine bottle forward. In the case of pressurized gas, the pressurized gas is sealed between the first and second sealing rings at the push rod flange. Although the pressurized gas is compressed and pushes the first arm 3320 and the second arm 3330 forward, the push rod 3300 is locked because the stop step 3350 of the first arm 3320 and the second arm 3330 is blocked by the rear end face of the locking sleeve 3500. Therefore, the push rod 3300 cannot push the piston and piston rod of the medicine bottle forward. Furthermore, the housing 3200 and the base 3100 are also biased away from each other by the retaining spring 3700, but they are kept in a stopped state by a pair of locking shoulders at the front end.

[0131] In the activated state, see Figure 26-27 The user presses the injection head (e.g., a medicine reservoir) against the patient's skin, applying pressure to the injection head. The skin then exerts a counterforce on the injection head, causing the injection head and housing 3200 to move towards the base 3100 against the spring force of the retaining spring 3700. Simultaneously, the first arm 3320 and the second arm 3330 approach the release hole 3620, with their inclined surface 3340 entering the release hole 3620. During this process, the release hole 3620 clamps the inclined surface 3340, again deforming the first arm 3320 and the second arm 3330, causing them to move closer together. Consequently, the stop steps 3350 also move closer together, thus moving away from the rear end face of the locking sleeve 3500 and no longer being blocked by it. At this point, the push rod 3300 is released from its locked state, and the push rod spring 3400 drives the push rod 3300 forward, which in turn pushes the piston and piston rod of the medicine reservoir forward to perform the injection operation. Under pressurized gas conditions, the pressurized gas expands and drives the push rod 3300 forward, which in turn pushes the piston and piston rod of the medicine storage bottle forward to perform the injection operation.

[0132] It should be noted that the features of the above three embodiments can be combined with each other to form new embodiments, all of which fall within the protection scope of this disclosure. For example, the needle-free injector body and the injection head can be combined with each other to form a new needle-free injector. For example, the injection head of the first embodiment can be mounted on the needle-free injector body of the second and third embodiments. The injection head of the second embodiment can be mounted on the needle-free injector body of the first and third embodiments.

[0133] This invention provides a needleless injector body and a needleless injector, which have a simple actuation structure, low cost and easy implementation. Simply press the needleless injector toward the patient's skin to a certain pressure to automatically trigger the injection and drug delivery.

[0134] The above description of various embodiments of the present invention is provided for illustrative purposes to a person skilled in the art. It is not intended to limit the invention to a single disclosed embodiment. As taught above, those skilled in the art will understand various alternatives and variations of the invention. Therefore, although some alternative embodiments have been specifically described, those skilled in the art will understand or relatively easily develop other embodiments. The present invention is intended to include all alternatives, modifications, and variations of the invention described herein, as well as other embodiments falling within the spirit and scope of the invention described above.

[0135] Figure label: 1000 needle-free injectors 10 medicine bottles 11 Pistons 12 piston rods 110 First Shell Section 1101 Positioning Shoulder 120 Second Shell Section 1201 Stop Shoulder 1210 safety jack 130 base 1301 base shoulder 140 hats 20 medicine bottle holder 200 locking sleeve 201 Annular Flange 202 Through Hole 210 external thread 250 retaining spring 300 release sleeve 301 Release Groove 302 Safety Slot 400 Actuating Sleeve 500 putter 501 stop groove 600 push rod spring 700 stop 2300 hats 2400 putter 2500 push rod spring 2510 concave part 7000 stop 2700 retaining spring 2620 positioning flange 2110 shell back shoulder 2710 Actuating Sleeve 2720 ​​mounting flange 2750 gasket 2770 auxiliary sleeve 2800 release sleeve 2910 preload spring 2930 Stopping Part Adjustment Sleeve 3100 base 3200 housing 3300 putter 3310 push rod flange 3320 First Arm 3330 Second Arm 3340 cone 3350 stop step 3400 push rod spring 3500 locking sleeve 3510 positioning shoulder 3520 through hole 3620 release hole 3700 retaining spring

Claims

1. A needle-free injector body, comprising: Base; A housing, which is connected to the base, defines an accommodating space; The push rod assembly is disposed in the receiving space near the base; An actuation mechanism is configured to lock the push rod assembly in a non-actuated position when in an actuated state and actuate the push rod assembly in an actuated state to achieve injection. The actuation mechanism includes: A locking sleeve is disposed adjacent to the push rod assembly and is used to lock the push rod assembly; A release device is disposed adjacent to the locking sleeve and is used to release the push rod assembly; A retaining spring is used to bias the locking sleeve and the release device in a direction away from each other; In the non-actuated state, the push rod assembly is blocked by the locking sleeve and cannot move forward; When the device enters the actuated state during use, the locking sleeve and the release device move closer to each other against the force of the retaining spring, thereby releasing the push rod assembly and allowing the push rod assembly to move from the non-actuated position to the actuated position.

2. The needleless injector body according to claim 1, wherein, The push rod assembly has a stop groove (501) near the front end of the housing. The locking sleeve (200) is fixedly connected to the base (130) and sleeved between the base (130) and the push rod assembly, and at least one through hole (202) is provided on the outer peripheral surface. The release device includes a release sleeve (300), which is sleeved on the locking sleeve (200) and can move along the outer surface of the locking sleeve (200), and has a release groove (301) on its inner circumferential surface. The retaining spring (250) is disposed between the release sleeve (300) and the base (130); In the non-actuated state, the stop groove (501) is aligned with the at least one through hole (202), and at least one stop (700) is disposed in the stop groove (501) and the at least one through hole (202) and blocked by the release sleeve (300). When the device enters the actuated state during use, the release sleeve (300) moves toward the base (130) against the action of the retaining spring (250) until the release groove (301) aligns with the at least one through hole (202), causing the push rod assembly to push the at least one stop (700) into the release groove (301), thereby allowing the push rod assembly to move from the non-actuated position to the actuated position.

3. The needleless injector body according to claim 2, wherein, The push rod assembly includes a push rod (500) and a push rod spring (600). The push rod spring (600) is disposed inside the push rod (500) and between the closed front end of the push rod (500) and the base (130). The stop groove (501) is disposed on the outer peripheral surface of the push rod (500).

4. The needleless injector body according to claim 2, wherein, The push rod assembly includes a push rod and pressurized gas sealed inside the push rod. A first sealing ring is provided at the front end of the push rod, and a second sealing ring is provided at intervals on the rear side of the first sealing ring, so that the pressurized gas is sealed between the first sealing ring and the second sealing ring.

5. The needleless injector body according to claim 3 or 4, wherein, The actuation mechanism further includes an actuation sleeve (400), which is disposed at the front end of the release sleeve (300) and is used to push the release sleeve (300) toward the base (130).

6. The needleless injector body according to claim 2, wherein, The housing includes a first housing segment (110) and a second housing segment (120), the second housing segment (120) being located between the first housing segment (110) and the base (130).

7. The needleless injector body according to claim 6, wherein, The first housing segment (110) and the second housing segment (120) are connected to the base (130) by threads.

8. The needleless injector body according to claim 6, wherein, The inner circumferential surface of the second housing segment (120) is provided with a stop shoulder (1201), and the front end face of the release sleeve (300) abuts against the stop shoulder (1201).

9. The needleless injector body according to claim 6, wherein, A positioning shoulder (1101) is provided on the inner peripheral surface of the first housing segment (110), and the front end face of the actuating sleeve (400) abuts against the positioning shoulder (1101).

10. The needleless injector body according to claim 2, wherein, The locking sleeve (200) is connected to the internal thread (1310) of the base (130) via an external thread (210).

11. The needleless injector body according to claim 2, wherein, The locking sleeve (200) is provided with an annular flange (201), and the retaining spring (250) is disposed between the release sleeve (300) and the annular flange (201).

12. The needleless injector body according to claim 11, wherein, The base (130) has a base shoulder (1301) on its inner circumferential surface, and the base shoulder (1301) is aligned with the annular flange (201).

13. The needleless injector body according to claim 6, wherein, The outer peripheral surface of the release sleeve (300) is provided with a safety groove (302), and the second housing section (120) is provided with a safety insertion hole (1210).

14. The needleless injector body according to claim 13, wherein, In the locked state, the safety slot (302) is aligned with the safety socket (1210), and the safety locking member passes through the safety socket (1210) and enters the safety slot (302).

15. The needleless injector body according to claim 2, wherein, The stop element is selected from the group consisting of: ball, needle roller, roller, wedge, and slider.

16. The needleless injector body according to claim 1, wherein, The push rod assembly has a recess (2510), and a locking sleeve (2600) is fitted onto the push rod assembly and has at least one through hole (2610) on its outer peripheral surface. The release device includes a release sleeve (2800), which is sleeved on the rear end of the locking sleeve (2600) and has a release groove on its inner circumferential surface; In the non-actuated state, the recess (2510) is aligned with the at least one through hole (2610), and at least one stop (7000) is disposed in the recess (2510) and the at least one through hole (2610) and blocked by the release sleeve (1500). When the device enters the actuated state during use, the retaining spring (2500) is compressed, and the locking sleeve (2600) moves toward the base until the release groove aligns with the at least one through hole (2610), causing the push rod assembly to push the at least one stop (7000) into the release groove, thereby allowing the push rod assembly to move from the non-actuated position to the actuated position.

17. The needleless injector body according to claim 16, wherein, The retaining spring (2700) is arranged around the locking sleeve (2600) and abuts against the housing back shoulder (2110) of the housing at one end. When the device enters the actuated state during use, the retaining spring (2500) is compressed against the back shoulder (2110) of the housing, and the locking sleeve (2600) moves toward the base until the release groove aligns with the at least one through hole (2610), causing the push rod assembly to push the at least one stop (7000) into the release groove, thereby allowing the push rod assembly to move from the non-actuated position to the actuated position.

18. The needleless injector body according to claim 16, wherein, The recess (2510) is either annular or rectangular.

19. The needleless injector body according to claim 16, wherein, The release sleeve is fixedly connected to the base or forms an integral structure.

20. The needleless injector body according to claim 16, wherein, The stop element is selected from the group consisting of: ball, needle roller, roller, wedge, and slider.

21. The needleless injector body according to claim 17, wherein, The push rod assembly includes a push rod (2400) and a pressurized gas sealed around the push rod. The front end of the push rod is provided with a push rod flange, and the recess (2510) is provided on the outer peripheral surface of the rear end of the push rod. A first sealing ring is provided on the rear side of the push rod flange.

22. The needleless injector body according to claim 17, wherein, The push rod assembly includes a push rod (2400) and a push rod spring (2500). The push rod spring (2500) is sleeved on the push rod. The front end of the push rod is provided with a push rod flange. The front end of the push rod spring abuts against the push rod flange. The recess (2510) is provided on the outer peripheral surface of the rear end of the push rod.

23. The needleless injector body according to claim 21 or 22, wherein, The actuation mechanism further includes an actuation sleeve (2710), which is disposed at the front end of the locking sleeve (2600) and is used to push the locking sleeve (2600) toward the base.

24. The needleless injector body according to claim 23, wherein, The rear end of the push rod spring abuts against the front end face of the actuating sleeve.

25. The needleless injector body according to claim 23, wherein, A second sealing ring is provided at the front end face of the actuating sleeve, so that the pressurized gas is sealed between the first sealing ring and the second sealing ring.

26. The needleless injector body according to claim 23, wherein, The actuating sleeve (2710) includes a locking flange (2720), and the front end of the retaining spring (2700) abuts against the locking flange (2720), such that the retaining spring (2700) is disposed between the actuating sleeve (2710) and the housing back shoulder (2110).

27. The needleless injector body according to claim 26 further includes an auxiliary sleeve (2770), the auxiliary sleeve being disposed inside the housing and sleeved outside the actuating sleeve (2710), the rear end of the auxiliary sleeve abutting against the locking flange (2720), and the front end abutting against the front shoulder of the housing.

28. The needleless injector body according to claim 23 further includes an auxiliary sleeve (2770), the auxiliary sleeve being disposed inside the housing and sleeved outside the actuating sleeve (2710), the front end of the retaining spring (2700) abutting against the rear end of the auxiliary sleeve, such that the retaining spring (2700) is disposed between the auxiliary sleeve (2770) and the rear shoulder (2110) of the housing.

29. The needleless injector body according to claim 23, wherein, The locking sleeve (2600) is provided with a positioning flange (2620). One end of the retaining spring (2700) abuts against the positioning flange (2620), and the other end abuts against the housing back shoulder (2110) or the release sleeve (2800) of the housing, so that the retaining spring (2700) is disposed between the locking sleeve (2600) and the housing back shoulder (2110) or the release sleeve (2800).

30. The needleless injector body according to claim 29 further includes an auxiliary sleeve (2770), the auxiliary sleeve being disposed inside the housing and sleeved outside the actuating sleeve (2710), the housing being provided with an auxiliary sleeve stop shoulder, such that the rear end of the auxiliary sleeve abuts against the auxiliary sleeve stop shoulder in the actuated state, and the front end of the auxiliary sleeve abuts against the front shoulder of the housing in the non-actuated state.

31. The needleless injector body according to claim 27, wherein, The auxiliary sleeve (2770), the actuating sleeve (2710), and the locking sleeve (2600) are an integral structure or fixedly connected together.

32. The needleless injector body according to claim 31, wherein, The front end of the release sleeve (2800) is provided with a locking inner circumferential surface, which is aligned with the at least one through hole (2610) in the locked state.

33. The needleless injector body according to claim 32, wherein, The front end of the release sleeve (2800) is a conical truncated platform, and the locking inner circumferential surface is the inner circumferential surface of the conical truncated platform.

34. The needleless injector body according to claim 32, further comprising: A stopper sleeve (2930) is disposed inside the locking sleeve (2600) and has a rear end flange. The rear end flange is blocked outside the rear end of the locking sleeve and abuts against a preload spring, which is disposed between the stopper sleeve and the base.

35. The needleless injector body according to claim 34, wherein, The locking sleeve (2600) is provided with a positioning flange (2620), and the rear end of the actuating sleeve (2710) abuts against the positioning flange (2620).

36. The needleless injector body according to claim 35, wherein, In the non-actuated state, the front end of the auxiliary sleeve (2770) abuts against the front shoulder of the housing, and the positioning flange (2620) is spaced apart from the rear shoulder (2110) of the housing.

37. The needleless injector body according to claim 36, wherein, In the actuated state, the front end of the auxiliary sleeve (2770) moves away from the front shoulder of the housing, the positioning flange (2620) abuts against the rear shoulder (2110) of the housing, and the stop sleeve (2930) blocks the at least one through hole.

38. The needleless injector body according to claim 1, wherein, The locking sleeve (3500) is connected to the housing and sleeved on the outside of the push rod assembly. The push rod assembly includes a first arm (3320) and a second arm (3330) spaced apart from each other. The rear ends of the first arm and the second arm are respectively provided with a conical surface (3340), and the front end of the conical surface (3340) is provided with a stop step (3350). The locking sleeve (3500) includes a through hole (3520) for the first arm and the second arm to pass through. The release device includes a release hole (3620) disposed in the base. In the non-actuated state, the stop step (3350) abuts against the rear end face of the locking sleeve (3500), and the push rod assembly is blocked by the locking sleeve. In the actuated state, the release hole applies an actuating force to the conical surface (3340), causing the stop step (3350) to move away from the rear end face of the locking sleeve (3500), thereby allowing the push rod assembly to move from the non-actuated position to the actuated position.

39. The needleless injector body according to claim 38, wherein, The locking sleeve (3500) has a positioning shoulder (3510) at its rear end, and the through hole (3520) axially penetrates the positioning shoulder. The front end of the retaining spring abuts against the rear end face of the locking sleeve (3500).

40. The needleless injector body according to claim 39, wherein, The push rod assembly includes a push rod (3300) and a push rod spring (3400). The push rod spring (3400) is sleeved on the push rod. The front end of the push rod is provided with a push rod flange (3310). The front end of the push rod spring abuts against the push rod flange (3310) and the rear end abuts against the positioning shoulder (3510).

41. The needleless injector body according to claim 38, wherein, The push rod assembly includes a push rod (3300) and a pressurized gas sealed around the push rod. The front end of the push rod is provided with a push rod flange (3310). A first sealing ring is provided on the rear side of the push rod flange, and a second sealing ring is provided at intervals on the rear side of the first sealing ring, so that the pressurized gas is sealed between the first sealing ring and the second sealing ring.

42. The needleless injector body according to claim 40 or 41, wherein, The first arm and the second arm are located at the rear end of the push rod.

43. The needleless injector body according to claim 42, wherein, When the first arm and the second arm enter the through hole (3520), the conical surface (3340) passes through the through hole (3520) and causes the first arm and the second arm to move closer to each other. After the stop step (3350) passes through the through hole (3520), the first arm and the second arm return to their original positions, so that the stop step (3350) abuts against the rear end face of the locking sleeve (3500).

44. The needleless injector body according to claim 43, wherein, In the actuated state, the locking sleeve moves toward the release hole, causing the first arm and the second arm to enter the release hole, the release hole clamping the conical surface (3340) so that the first arm and the second arm move toward each other, the stop step (3350) moves away from the rear end face of the locking sleeve (3500), and the push rod moves away from the through hole (3520), thereby allowing the push rod assembly to move from the non-actuated position to the actuated position.

45. A needle-free injector, comprising a needle-free injector body according to any one of claims 1 to 44 and an injection head mounted on the front end of the needle-free injector body.

46. ​​The needleless injector according to claim 45, wherein, The injection head includes a drug reservoir (10), a piston (11) capable of pushing the drug solution forward within the drug reservoir (10), and a piston rod (12) connected to the piston (11).

47. The needleless injector according to claim 46, wherein, The piston (11) is connected to the piston rod (12) by means of threaded connection, adhesive, or flange connection.

48. The needleless injector according to claim 46, wherein, In the locked state, the piston rod (12) is spaced a certain distance from the push rod assembly. In the actuated state, the push rod assembly pushes the piston rod (12) to move.

49. The needleless injector according to claim 46, wherein, The injection head also includes a drug reservoir support (20), which surrounds the drug reservoir (10) and supports the drug reservoir (10) in the housing.

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