Multi-step needle-free injector or needle-free injection system, and their driving methods and control programs

Abstract

The objective of this invention is to develop a multi-step needleless syringe that can repeatedly inject an injectable solution from a single ampoule in multiple stages. [Means for solving the problem] The present invention drives an elastic energy storage unit that stores energy in an elastic body that presses a piston, and a piston head stop position adjustment unit that adjusts the stopping position of the piston head, both of which are driven by actuators, and controls these actuators by a control unit. The present invention provides a needleless syringe or needleless injection system that repeatedly performs the following actions: a) storing energy in an elastic body by an elastic body energy storage unit, b) changing the piston head stop position forward by a piston head stop position adjustment unit, and c) driving the piston forward by releasing the energy of the elastic body, thereby gradually pressing and advancing the plunger that pushes out the injection solution in the ampoule with the piston head, and repeatedly injecting the injection solution in a single ampoule in multiple portions.

Description

Technical Field

[0001] The present invention relates to a needleless syringe or a needleless injection system that can inject an injection solution subcutaneously or into the skin at high speed by the force of an elastic body such as a spring without using a needle, and provides a multi-step type needleless syringe or needleless injection system that can divide and repeatedly inject the injection solution in a single ampoule multiple times. Further, the present invention provides a driving method and a control program for a needleless syringe or a needleless injection system that enable the injection solution in a single ampoule to be divided and repeatedly injected multiple times.

Background Art

[0002] A needleless syringe is a medical device that can inject an injection solution subcutaneously or into the skin without using a needle by ejecting the injection solution at high speed from a nozzle having a minute diameter. Since a needleless syringe does not pierce the skin with a needle, it has an advantage of less pain compared to a syringe using a needle, and also has an advantage of preventing infections such as viruses and injuries caused by needle stick accidents.

[0003] These advantages of the needleless syringe are particularly great in medical treatment for children who are afraid of injection with a needle and patients with acrophobia. In 2020, the sale of the needleless syringe Injex50 was started in Japan after the needleless syringe developed by the applicant of this application obtained the approval for manufacturing and selling of medical devices for the first time in Japan. At the time of filing this application, its use has been particularly expanding in pediatric dentistry. sale was started, but at the time of filing this application, its use has been particularly expanding in pediatric dentistry.

[0004] The most common driving principle for needleless syringes is the use of elastic force, such as that provided by a spring. Other methods include using gas pressure, electromagnetic force, or explosives. However, methods using gas pressure or electromagnetic force have difficulty injecting the solution at high speed. Therefore, when the solution is small, it can be injected into the skin (epidermis and dermis), but not into the subcutaneous tissue (tissue deeper than the dermis). Methods using explosives have problems with controlling the explosive force and ensuring safety. On the other hand, methods using elastic force, such as that provided by a spring, work by continuously applying stress to an elastic body to deform it and accumulate elastic energy (energy storage of the elastic body), and then releasing the deformed elastic body to release the accumulated elastic energy all at once (energy release of the elastic body). This allows for high-speed injection of the solution, and the amount of elastic energy used for injection remains constant. Because of these characteristics, methods using elastic force, such as that provided by a spring, can reliably and safely inject even small amounts of solution subcutaneously, making them the most suitable for needleless syringes.

[0005] The driving principle of conventional needleless syringes that utilize the elastic force of springs, etc., will be explained as follows using the diagram described in Patent Document 1, which was previously filed by one of the inventors of this application. Figure 8 is a drawing in which Fig. 23 and Fig. 24 of Patent Document 1 have been given new reference numerals in accordance with the reference numerals used in this application. Figure 8(A) shows a conventional needleless syringe with the spring compressed and energized, while Figure 8(B) shows the compressed spring released and the injection fluid ejected. As shown in Figure 8(A), an ampoule 3A can be attached to the front of the needleless syringe 1A. The ampoule 3A has a cylinder-like structure and contains an injection solution inside, and the injection solution can be ejected by pushing the plunger 304A into the cylinder-like structure. Inside the body of the needleless syringe 1A is a piston 5A that can slide back and forth, and a piston head 522A is provided at the front end of the piston 5A. Furthermore, a spring 6A is installed inside the needleless syringe 1A that applies a forward force to the piston 5A. By manually moving the piston 5A backward, the spring 6A becomes compressed, as shown in Figure 8(A). Here, the trigger finger 1211A stops the piston 5A from moving forward, maintaining the compressed "energy stored" state of the spring 6A. The trigger finger 1211A is located at the front end of the trigger 1210A. By using the force of another spring to lift the push end 1212A located at the rear end of the trigger 1210A, the trigger finger 1211A is pushed down by the principle of leverage, preventing the piston 5A from moving forward. To maintain the lifted position of the push end 1212A, a safety lock 1220A, which is movable back and forth, is pushed under the push end 1212A to lock it in place. Next, as shown in Figure 8(B), the safety lock 1220A is moved backward to release the lock, and then the push end 1212A is pushed downward to lift the trigger finger 1211A using the lever principle, allowing the piston 5A to be freely driven forward by the force of the spring 6A. By releasing the spring 6A in this way and driving the piston 5A forward at high speed, the piston head 522A presses against the plunger 304A, allowing the injection fluid in the ampoule 3A to be ejected at high speed from the small diameter outlet 303A.

[0006] In the treatment of skin diseases and in the fields of cosmetic medicine and hair restoration, medication is sometimes injected into multiple locations on the skin. If a multi-step needleless injector is developed that dispenses the solution from a single ampoule in multiple steps, more efficient treatment will be possible in these medical fields as well.

[0007] Needleless syringes that utilize the elastic force of springs or the like work by storing energy in an elastic body such as a spring and then releasing that energy to inject the solution. Therefore, it was previously clear to those skilled in the art that continuous injection within a predetermined time is not possible, and that the amount injected in a single injection cannot be set (paragraphs

[0010] and

[0011] of Patent Document 2). For this reason, the inventors of Patent Document 2 have succeeded in developing a needleless injection system that allows setting the number of continuous injections, the time interval between continuous injections, and the amount injected in a single injection by employing a method that utilizes gas pressure (paragraph

[0001] of Patent Document 2).

[0008] However, as mentioned above, since a method utilizing the elastic force of springs is most suitable for needleless syringes, attempts are being made to develop a multi-step needleless syringe using a method utilizing the elastic force of springs (Patent Documents 3 to 5). Patent Document 3 discloses a needleless syringe that can inject an injection in several portions by gradually releasing the stored energy from a spring in multiple stages, thereby gradually pressing the plunger in multiple stages. Furthermore, Patent Documents 4 and 5 disclose a needleless syringe capable of multiple injections by transmitting the force of a spring-driven piston to a plunger via a cylindrical stepped barrel (revolver) having multiple spiral-shaped steps. Specifically, initially, the lowest step of the stepped barrel (revolver) is in contact with the plunger, and the pressure of the piston driven by the stored and released spring force is transmitted to the plunger via the stepped barrel (revolver), causing the plunger to move forward and perform the first injection. Next, the stepped barrel (revolver) is rotated so that the next step, located further forward, is in contact with the plunger, and then the pressure of the piston driven by the stored and released spring force is transmitted to the plunger via the stepped barrel (revolver), causing the plunger to move further forward and perform the second injection. By repeating this operation, multiple injections can be performed. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] International Publication No. WO2014 / 042930 [Patent Document 2] Japanese Patent Publication No. 2015-036108 [Patent Document 3] Japanese Patent Publication No. 2012-055641 [Patent Document 4] Special Publication No. 2022-527712 [Patent Document 5] Japanese Patent Publication No. 2020-179038 [Overview of the project] [Problems that the invention aims to solve]

[0010] As mentioned above, attempts have been made to develop a multi-step needleless syringe that uses the elastic force of a spring or the like to inject the injection solution from a single ampoule in multiple stages (Patent Documents 3 to 5). However, the needleless syringe described in Patent Document 3 injects the injection solution by releasing the stored energy from the spring in stages in multiple stages. At the time of the first release, the spring is sufficiently compressed and has high elastic stress, but as the staged release is repeated, the spring stretches and the elastic stress decreases, resulting in a weakening of the injection force and the inability to obtain a constant injection force. Furthermore, the needleless syringes described in Patent Documents 4 and 5 utilize a cylindrical stepped barrel (revolver) with multiple spiral-shaped steps, allowing for multiple injections by rotating the stepped barrel (revolver) to change the position of the steps that contact the plunger. However, since the amount injected per injection is determined by the step height of the stepped barrel (revolver), the amount injected and the injection pressure per injection are physically fixed, and there is a problem in that the amount injected and the injection pressure of the injection solution cannot be adjusted. In addition, the needleless syringes described in Patent Documents 4 and 5 require the compression of a spring and the rotation of the stepped barrel (revolver) to be performed manually at the same time, which necessitates weakening the spring force, making it difficult to deliver the drug solution subcutaneously.

[0011] Therefore, the objective of the present invention is to develop a new multi-step needleless syringe with a new drive mechanism that can repeatedly inject the injectable solution from a single ampoule in multiple stages, maintain a constant injection force even with repeated injections, allow adjustment of the injection volume and injection pressure of the injectable solution, and further enable automatic continuous injection without manual intervention. [Means for solving the problem]

[0012] To solve these problems, the inventors conducted extensive research and found that by using a piston connected to a piston base, which allows the piston rod equipped with a piston head to change its relative front-to-back position with respect to the piston base, it becomes possible to arbitrarily adjust the position at which the piston head that presses the plunger stops. Furthermore, by driving a piston head stop position adjustment unit that adjusts the stopping position of the piston head and an elastic body energy storage unit that stores energy in an elastic body that presses the piston with actuators, and controlling these actuators with a control unit, the inventors found that by repeatedly performing a) energy storage of the elastic body by the elastic body energy storage unit, b) changing the position of the piston head stop position forward by the piston head stop position adjustment unit, and c) driving the piston forward by releasing the energy of the elastic body, the plunger that pushes out the injection fluid in the ampoule is pressed forward in stages by the piston head and advanced, making it possible to repeatedly inject the injection fluid in a single ampoule in multiple portions. Furthermore, we discovered that because the elastic body can be charged and injected each time, a constant injection force can be achieved. By adjusting the distance at which the piston head stops, the injection volume and pressure of the injected fluid can be adjusted. Additionally, because an actuator is used instead of manual operation, automatic rapid firing is possible, which led to the completion of this invention. In other words, the present invention provides the following [1] invention of a needle-free syringe or needle-free injection system. [1] A needleless syringe or needleless injection system comprising a machine frame body to which an ampoule having a plunger for pushing out an internal injection solution can be attached to the front, a piston provided on the machine frame body so as to be slidable back and forth, and an elastic body that applies a forward force to the piston, wherein by releasing the stored energy of the elastic body to drive the piston forward, the piston head of the piston presses the plunger and injects the injection solution in the ampoule, An elastic body energy storage unit that stores energy in the elastic body by moving the piston backward, A first actuator that drives the elastic energy storage unit, A piston head stop position adjustment unit adjusts the piston head stop position at which the piston head stops when the stored energy in the elastic body is released and the piston is driven forward, A second actuator that drives the piston head stop position adjustment unit, It comprises a control unit that controls the first actuator and the second actuator, The piston comprises a piston base to which a forward force is applied by the elastic body, and a piston rod equipped with the piston head. The piston rod is connected to the piston base so that it can receive a forward force from the piston base and can change its relative front-to-back position with respect to the piston base. The piston head stop position adjustment unit can adjust the piston head stop position by changing the relative position of the piston rod with respect to the piston base back and forth using the driving force of the second actuator. The control unit controls the driving of the first actuator and the second actuator, thereby accumulating energy in the elastic body by the elastic body energy storage unit, changing the piston head stop position forward by the piston head stop position adjustment unit, and driving the piston forward by releasing the energy of the elastic body. A needle-free syringe or needle-free injection system characterized by repeatedly performing the following.

[0013] The needleless injector or needleless injection system of the present invention has a piston head stop position adjuster capable of adjusting the stop position of the piston head. Therefore, by adjusting the distance of changing the piston head stop position forward, it is possible to change and set the number of injections per ampoule or the injection liquid amount per injection. The inventors of the present invention provide a needleless injector or needleless injection system with an interface for setting the number of injections per ampoule or the injection liquid amount per injection, and by controlling an actuator that drives the piston head stop position adjuster according to the setting by the user via the interface, it has been found that the user can change and set the number of injections per ampoule or the injection liquid amount per injection. That is, the present invention provides the invention of the needleless injector or needleless injection system of the following [2]. [2] Further having an interface for setting the number of injections per ampoule or the injection liquid amount per injection, The control unit controls the driving amount of the second actuator according to the number of injections per ampoule or the injection liquid amount per injection set by the user via the interface, thereby controlling the distance of the forward position change of the piston head stop position. The needleless injector or needleless injection system according to [1] above.

[0014] The needleless injector or needleless injection system of the present invention uses a piston rod that can receive a forward force from the piston base and is connected to the piston base so as to be able to change the relative front and rear positions with respect to the piston base. As such a connection structure between the piston rod and the piston base, as described later, it is not particularly limited and can take various structures, but the structure connected by male and female threads is the simplest and can be easily manufactured. That is, the present invention provides the invention of the needleless injector or needleless injection system of the following [3]. [3] The piston rod and the piston base are connected to each other by a male thread and female thread structure, The needleless injector or needleless injection system according to [1] or [2], wherein the piston head stop position adjusting part changes the position of the piston rod relative to the piston base back and forth by relatively rotating the piston rod and the piston base with the driving force of the second actuator.

[0015] When the connection structure of [3] is adopted, it is necessary to relatively rotate the piston rod and the piston base with the driving force of the actuator. When rotating the piston rod, it is preferable that the structure of the piston rod and the piston head stop position adjusting part be as follows in [4]. That is, the present invention provides an invention of a needleless injector or needleless injection system as follows in [4]. [4] A spur gear having a plurality of teeth of a tooth stripe linearly extending in the front - rear direction is formed on the outer periphery of a part of the piston rod. The piston head stop position adjusting part has a cylindrical internal gear that is slidable back and forth with respect to the spur gear and has a plurality of teeth of a tooth stripe linearly extending in the front - rear direction on its inner periphery. The needleless injector or needleless injection system according to [3], characterized in that regardless of the position of the piston rod sliding back and forth, the rotational driving force of the second actuator can be transmitted to the spur gear through the internal gear to rotate the piston rod.

[0016] As the elastic body energy storage part of the needleless injector or needleless injection system of the present invention, as will be described later, it is not particularly limited and various mechanisms can be adopted. However, if a cam mechanism as follows in [5] is used, it is preferable because the rotational driving force of the actuator can be easily converted into the driving force in the front - rear direction of the piston. That is, the present invention provides an invention of a needleless injector or needleless injection system as follows in [5]. [5] The elastic body energy storage part has a cam that can convert the rotational motion of the first actuator into the motion of the piston in the front - rear direction. The needleless syringe or needleless injection system according to any one of [1] to [4], wherein the cam is rotatably mounted around an axis in the front-rear direction on which the piston slides, and the thickness in the front-rear direction of the portion of the cam that contacts the piston changes with the rotation of the cam, thereby converting the rotational motion of the first actuator into the front-rear motion of the piston to store energy in the elastic body.

[0017] If the cam mechanism described in [5] above is adopted, it is preferable to further use the cam shape as shown in [6] below, because this allows for continuous energy storage and release of the elastic body. In other words, the present invention provides the following [6] invention of a needle-free syringe or needle-free injection system. [6] The cam has a shape in which the thickness in the front-rear direction of the portion that contacts the piston gradually increases with the rotation of the cam, thereby enabling the storage of energy in the elastic body, The thickness of the portion that contacts the piston has a stepped shape that rapidly decreases as the cam rotates, thereby enabling the release of the elastic body. The needleless syringe or needleless injection system according to [5], characterized by having the following:

[0018] The needle-free syringe or needle-free injection system of the present invention further includes a sensor that detects the front-rear position of the piston rod and a sensor that detects the front-rear position of the piston base, thereby preventing excessive force from being applied to components such as the piston, elastic body, and ampoule, and enabling more precise control of the piston head position. In other words, the present invention provides the following [7] invention of a needle-free syringe or needle-free injection system. [7] A piston rod position sensor or that can detect the position of the piston rod in the front-rear direction and transmit the detection result to the control unit. A piston base position sensor capable of detecting the front-to-back position of the piston base and transmitting the detection result to the control unit. A needle-free syringe or needle-free injection system according to any one of the above [1] to [6], further comprising the above.

[0019] While needleless syringes have difficulty penetrating loose skin when injecting fluid, they can easily penetrate taut skin and inject subcutaneously. Therefore, it is preferable to attach an attachment to the front end of the needleless syringe, press the attachment against the skin to taut it, and then inject the fluid. However, pressing the attachment against the skin causes pressure pain, which is a problem, especially when performing needleless injections on the face for cosmetic purposes, and this problem was not solved even when the attachment was molded from a flexible material. Therefore, the inventors have developed a vacuum attachment that can taut the skin by using negative pressure from suction to attract the skin to the attachment without having to press it against the attachment. In other words, the present invention provides the following [8] invention of a needle-free syringe or needle-free injection system. [8] A vacuum attachment having a cylindrical shape with two open ends, one of which can be attached to the plunger or the front of the machine frame body to which the plunger is attached, and the other open end can be brought into contact with the skin, A suction device that can make the skin adhere tightly to the attachment by sucking the air inside the vacuum attachment, A needle-free syringe or needle-free injection system according to any one of [1] to [7], further comprising:

[0020] The present invention also provides the invention of a method for driving a needleless syringe or needleless injection system as described in [9] and

[10] below. [9] A method for driving a needleless syringe or needleless injection system comprising a machine frame body to which an ampoule having a plunger for pushing out an internal injection solution can be attached to the front, a piston provided on the machine frame body so as to be slidable back and forth, and an elastic body that applies a forward force to the piston, wherein the elastic body, which has stored energy, is released to drive the piston forward, thereby pressing the plunger with the piston head and ejecting the injection solution in the ampoule, A) A step of storing energy in the elastic body using an elastic body energy storage unit that stores energy in the elastic body by moving the piston backward, and a first actuator that drives the elastic body energy storage unit, B) A step of changing the piston head stop position to a forward position using a piston head stop position adjustment unit that adjusts the piston head stop position at which the piston head stops when the stored energy in the elastic body is released and the piston is driven forward, and a second actuator that drives the piston head stop position adjustment unit, C) The step of releasing the elastic body to drive the piston forward, pressing the plunger with the piston head of the piston, and injecting the injection solution in the ampoule. A method for driving a needleless syringe or needleless injection system, characterized by repeatedly performing the following steps.

[0021]

[10] A method for driving a needleless syringe or needleless injection system according to [9], characterized in that, in step B), the amount of drive of the second actuator is controlled according to the number of injections of the injection solution or the amount of injection solution per injection set by the user, thereby controlling the distance of the forward position change of the piston head stop position.

[0022] In the driving method for a needleless syringe or needleless injection system of the present invention, if the steps of A) storing energy in an elastic body and B) changing the piston head stop position to a forward position are performed simultaneously, the operating time for injecting the injection solution can be shortened, making it a preferred driving method. In other words, the present invention provides an invention for a method of driving a needleless syringe or needleless injection system as described below

[11] .

[11] A method for driving a needle-free syringe or needle-free injection system according to [9] or

[10] , characterized in that step A) and step B) are performed simultaneously.

[0023] In the driving method for a needleless syringe or needleless injection system of the present invention, a sensor is used to detect the position of the piston rod. When it is detected that the piston rod has moved forward beyond a predetermined position, the driving of the second actuator is stopped. This prevents excessive force from being applied to components such as the piston and ampoule, and allows for more precise control of the piston head position. Furthermore, when steps A) of storing energy in the elastic body and B) of changing the piston head stop position to a forward position are performed simultaneously, if the speed at which the piston rod moves forward is faster than the speed at which the piston base retracts, the piston head will press against the plunger and the injection fluid will leak out. However, by stopping the actuator based on the sensor that detects the position of the piston rod, such leakage can be prevented. In other words, the present invention provides an invention for a method of driving a needleless syringe or needleless injection system as described below

[11] .

[12] A method for driving a needleless syringe or needleless injection system according to any one of [9] to

[11] , characterized in that, in step B), a piston rod position sensor is used to detect the position of the piston rod in the front-rear direction, and if it is detected that the position of the piston rod has moved forward beyond a predetermined position, the driving of the second actuator is stopped.

[0024] In the driving method for a needleless syringe or needleless injection system of the present invention, if the steps of A) storing energy in the elastic body, B) changing the piston head stop position to a forward position, and C) releasing energy in the elastic body and injecting the injection fluid are performed in quick succession immediately before injecting the injection fluid, it becomes unnecessary to maintain the state in which the elastic body is stored energy for a long time, and accidental injection, which would result in the injection fluid being injected when the user does not intend it, can be prevented, thus making it a preferred driving method. In other words, the present invention provides the following

[13] invention of a method for driving a needleless syringe or needleless injection system.

[13] A method for driving a needleless syringe or needleless injection system according to any one of [9] to

[12] , characterized in that the steps A) to C) are performed immediately before the injection of the injection solution.

[0025] The present invention further provides control programs for the following needleless injectors or needleless injection systems:

[14] to

[17] .

[14] Control unit of the needleless injector or needleless injection system described in [1] above A') A step of generating a command signal to drive the first actuator by a predetermined amount in order to store energy in the elastic body, B') A step of generating a command signal to drive the second actuator by a predetermined amount in order to change the piston head stop position to a forward position, C') A step of generating a command signal to release the energy stored in the elastic body in order to release the energy stored in the elastic body. A control program characterized by causing it to perform information processing that includes such processing.

[0026]

[15] A predetermined amount to drive the second actuator in step B') based on the number of injections or the amount of injection per injection set by the user. The control program according to

[14] , characterized in that it causes the control unit to further perform information processing to identify the

[0027]

[16] Simultaneous signal generation in step A') and signal generation in step B') The control program according to

[14] or

[15] , characterized in that it is executed by the control unit.

[0028]

[17] A control program according to any one of

[14] to

[16] , characterized in that immediately after receiving a signal from the user instructing injection through an interface, the control unit performs the information processing described in A') to C'). [Effects of the Invention]

[0029] The needle-free syringe or needle-free injection system, as well as the driving method and control program for the needle-free syringe or needle-free injection system of the present invention, drives an elastic body energy storage unit that stores energy in an elastic body with an actuator, drives a piston head stop position adjustment unit that adjusts the stopping position of the piston head with an actuator, and controls the driving of these actuators with a control unit, thereby repeatedly performing the storage of energy in the elastic body by the elastic body energy storage unit, the forward position change of the piston head stop position by the piston head stop position adjustment unit, and the forward driving of the piston by the release of energy in the elastic body. As a result, the plunger that pushes out the injection liquid in the ampoule is pressed forward in stages by the piston head, and the injection liquid in a single ampoule can be repeatedly injected in multiple batches. [Brief explanation of the drawing]

[0030] [Figure 1] This is a schematic diagram showing the internal structure of a needleless syringe according to the first embodiment of the present invention. [Figure 2] Figure 1 is a cross-sectional view of the needleless syringe according to the first embodiment. Figure 2(A) shows a plan view including the dashed line C1-C2 in Figure 1, and Figure 2(B) shows a plan view including the dashed line C3-C4 in Figure 1. [Figure 3]Figure 3(A) is a schematic diagram showing the state in which the cam and piston follower are in contact with each other in the needleless syringe of the first embodiment, and the change in the thickness of the cam. Figure 3(A) is a schematic diagram of the state in which the cam and piston follower are in contact, viewed from the rear along the axis on which the piston slides in Figure 1. Figure 3(B) is a graph showing the change in the thickness of the cam at the point where the cam and piston follower are in contact when the large gear rotates. [Figure 4] This is a schematic diagram showing the operation of the internal structure of the needleless syringe of the first embodiment when the piston head stopping position is changed and the elastic body is released. Figure 4(A) shows the state in which the piston head has moved forward from the state in Figure 1. Figure 4(B) shows the state in which the piston has been driven forward by releasing the elastic body (coil spring) from the state in Figure 4(A) and has stopped. [Figure 5] This flowchart shows the information processing that the injection control program, which is part of the control program for the needleless syringe of the first embodiment, causes the information processing device to execute. [Figure 6] This is a schematic diagram showing a needle-free injection system according to a second embodiment of the present invention. [Figure 7] Figure 7 is a schematic diagram showing the cross-sectional structure and usage method of the front end of a multi-step injector with a vacuum attachment. Figure 7(A) shows the state before the skin is attached to the vacuum attachment, and Figure 7(B) shows the state after the skin has been attached to the vacuum attachment. [Figure 8] This diagram illustrates the driving principle of a conventional needleless syringe that utilizes the elastic force of springs or similar materials. [Modes for carrying out the invention]

[0031] 1. Needle-free syringe or needle-free injection system 1-1. Overview of Needle-Free Syringes or Needle-Free Injection Systems The needleless syringe or needleless injection system of the present invention is a needleless syringe that utilizes the elastic force of an elastic body such as a spring. It uses a piston that is slidably mounted back and forth and an elastic body that applies a forward force to the piston. By releasing the stored energy of the elastic body and driving the piston forward, the piston head presses against the plunger of the ampoule, injecting the injection solution inside the ampoule at high speed. In this invention, "elastic body" refers to a member that deforms when stress is applied and returns to its original shape when the stress is removed. While "elastic body" is not limited to these examples, examples of elastic bodies that can be used include coil springs, leaf springs, compression springs, tension springs, rubber, and the like. In this invention, "energy storage" refers to the process of continuously applying stress to an elastic body to deform it and store elastic energy in the elastic body, and "energy release" refers to the process of releasing the stress and returning the deformed elastic body to its original shape, thereby converting the stored elastic energy into kinetic energy.

[0032] The ampoule used in the needleless syringe or needleless injection system of the present invention can be attached to the front of the main body of the needleless syringe. An ampoule typically has a cylinder that contains the injection solution, a nozzle with a small diameter provided at the front end of the cylinder, and a plunger that can be inserted into the cylinder and pushes out the injection solution inside. Since the injection solution injected into the body must be sterile, ampoules are used by injecting sterile injection solution into a sterile ampoule, or by purchasing ampoules that have already been injected with the injection solution. Used ampoules, from which all the injection solution has been injected, are usually disposable, and repeated injections can be performed by removing the ampoule attached to the front of the main body of the needleless syringe and replacing it with a new ampoule. Thus, the ampoule can be a separate component from the needleless syringe of the present invention, and the needleless syringe of the present invention may be sold with the ampoule removed. Furthermore, the ampoule may be reused. For example, by providing an injection port for injecting the injection solution into the ampoule and attaching the injection solution injector to the needleless syringe of the present invention, the injection solution inside the ampoule can be repeatedly injected and reused without replacing the ampoule.

[0033] The needleless syringe or needleless injection system of the present invention is characterized by including, in addition to a machine frame body to which an ampoule can be attached to the front, a piston provided on the machine frame body so as to be slidable back and forth, an elastic body that applies a forward force to the piston, an elastic body energy storage unit that stores energy in the elastic body by moving the piston backward, a first actuator that drives the elastic body energy storage unit, a piston head stop position adjustment unit that adjusts the position at which the piston head stops when the stored energy in the elastic body is released and the piston is driven forward, a second actuator that drives the piston head stop position adjustment unit, and a control unit that controls the first actuator and the second actuator. The needle-free syringe or needle-free injection system of the present invention may further have configurations other than those described above. In the present invention, the above configuration may be divided into multiple devices, in which case it becomes a needle-free injection system. For example, although not limited thereto, the control unit may be a separate control device from the needle-free injector body, and the needle-free injector body and the control device may be connected by wire or wireless communication to form a needle-free injection system.

[0034] The "elastic energy storage unit" of the needleless syringe or needleless injection system of the present invention is not particularly limited as long as it is a mechanism that can move the piston backward using the driving force of the actuator, and any mechanism may be used. Since the elastic body applies a forward force to the piston, by moving the piston backward, the elastic body can deform (compress or stretch in the case of a coil spring) and store elastic energy. In this invention, "forward direction" means the direction in which the piston presses against the plunger of the ampoule on the axis in which the piston slides back and forth. "Rearward direction" means the opposite direction to "forward direction". As a mechanism that can move a piston backward using the driving force of an actuator, for example, a mechanism that can convert the rotational motion of the actuator into linear motion can be used. Such mechanisms are not limited to these, but examples include cam mechanisms, ball screw mechanisms, timing belt mechanisms, rack and pinion mechanisms, etc.

[0035] The "elastic energy storage unit" of the needle-free syringe or needle-free injection system of the present invention may be equipped with a function to release the force that moves the piston backward, thereby releasing the elastic energy. Alternatively, a mechanism separate from the "elastic energy storage unit" may be used to hold the piston in its position after it has moved backward, and then release it to release the elastic energy. Such a separate mechanism could be, for example, a trigger or safety lock mechanism as disclosed in Patent Document 1, although this is not limited to such a mechanism. However, if the piston that has moved backward is held by a trigger or safety lock mechanism, there is a risk that the trigger may be activated unexpectedly due to malfunction, causing the injection fluid to be ejected and potentially injuring the human body. Therefore, in the needle-free syringe or needle-free injection system of the present invention, it is preferable that the backward movement of the piston by the elastic energy storage unit and the release of that movement occur in quick succession immediately after the user performs the injection operation.

[0036] The "piston head stop position adjustment unit" of the needleless syringe or needleless injection system of the present invention is a mechanism for adjusting the position at which the piston head stops when the stored energy in the elastic body is released and the piston is driven forward (referred to as the "piston head stop position" in the present invention). When the piston head presses against the plunger to inject the injection fluid in the ampoule, the plunger is pushed in to the position where the piston head stops and the injection fluid is injected. Therefore, by adjusting the piston head stop position, it is possible to adjust the amount of injection fluid injected. The adjustment of the piston head stop position is made possible by using a piston with the following mechanism. The piston used in the needleless syringe or needleless injection system of the present invention comprises a piston base to which a forward force is applied by an elastic body, and a piston rod equipped with a piston head. Here, the piston rod is connected so as to be able to receive a forward force from the piston base, so that the forward force received by the piston base from the elastic body can be transmitted to the piston rod, and the piston head provided on the piston rod can press against the plunger. At the same time, since the piston rod is connected to the piston base so as to be able to change its relative front-to-back position to the piston base, it is possible to adjust the stopping position of the piston head. The method of connecting the piston rod and the piston base is not particularly limited; for example, methods such as connecting them using a male-to-female thread structure or connecting them as part of a hydraulic cylinder structure can be used.

[0037] The "actuator" of the needleless syringe or needleless injection system of the present invention is not particularly limited, and any component or device capable of generating driving force can be used as an actuator. Examples of actuators that can be used include, but are not limited to, servo motors, stepping motors, linear motors, hydraulic actuators, pneumatic actuators, ultrasonic motors, and the like. In the present invention, the elastic energy storage unit is driven by the first actuator and the piston head stop position adjustment unit is driven by the second actuator. However, if a mechanism is provided in which a single actuator can transmit driving force to both the elastic energy storage unit and the piston head stop position adjustment unit, the first actuator and the second actuator may be the same actuator.

[0038] The needleless syringe or needleless injection system of the present invention stores energy in an elastic body by an elastic body energy storage unit and controls the piston head stop position with a piston head stop position adjustment unit. However, when continuously injecting the injection fluid, repeatedly manually driving the elastic body energy storage unit places a heavy burden on the user. Furthermore, it is difficult to accurately control the piston head stop position by manually driving the piston head stop position adjustment unit. In order to prevent accidental injection of the injection fluid when the user does not intend to inject it, it is preferable to perform a series of operations in a short time immediately after the user initiates the injection, including the backward movement of the piston by the elastic body energy storage unit, the adjustment of the piston head stop position by the piston head stop position adjustment unit, and the forward movement of the piston by releasing the energy of the elastic body. However, it is impossible to perform these operations manually in a short time. Therefore, the needleless syringe or needleless injection system of the present invention is equipped with a first actuator that drives an elastic body energy storage unit, a second actuator that drives a piston head stop position adjustment unit, and a control unit that controls these as essential components. These components repeatedly store energy in the elastic body by the elastic body energy storage unit, change the piston head stop position forward by the piston head stop position adjustment unit, and drive the piston forward by releasing the energy of the elastic body. This makes it possible to push the plunger that pushes out the injection fluid in the ampoule forward in stages with the piston head, and to repeatedly inject the injection fluid in a single ampoule in multiple batches.

[0039] 1-2. First Embodiment Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. Figure 1 is a schematic diagram showing the internal structure of a needleless syringe according to the first embodiment of the present invention. As shown in Figure 1, the needleless syringe 1 of the present invention has a structure in which the main body frame 2 serves as the housing of the device, and various components such as a piston 5, an elastic body (coil spring) 6, an elastic body energy storage unit 7, a first actuator (motor) 8, a piston head stop position adjustment unit 9, a second actuator (motor) 10, and a control unit 11 are mounted inside. An ampoule 3 can be attached to the front of the main body frame 2. The machine frame body 2 has a nearly cylindrical shape overall, and at the front, it has multiple steps, giving it a shape like multiple cylinders of different diameters stacked on top of each other. In the first embodiment, the machine frame body serves as the housing, but the present invention is not limited to this embodiment. Any machine frame body is acceptable as long as it is capable of attaching an ampoule to the front and has a piston mounted so as to be slidable back and forth.

[0040] 1-2-1. Ampoule As shown in Figure 1, the front of the main body 2 of the device frame is structured to accommodate an ampoule 3. The ampoule 3 is a separate, disposable consumable item from the needleless syringe 1. The user purchases the ampoule 3 sealed in a sterile package and attaches it to the opening at the front of the main body 2 of the device frame. The ampoule 3 has a cylindrical cylinder 302 that contains the injection solution 301, and a small-diameter discharge nozzle 303 is provided at its front end. A plunger 304 is inserted into the cylinder 302, and by pushing the plunger 304 in, the injection solution 301 contained inside the cylinder 302 can be ejected from the discharge nozzle 303. A male thread 305 is formed at the rear of the cylinder 302, and it is shaped to fit into a female thread 201 formed in the opening at the front of the machine frame body 2. The ampoule 3 can be installed in the opening at the front of the machine frame body 2 by fitting the male and female threads together. The ampoule 3 is provided with an annular stopper 306, and when the male thread 305 of the cylinder 302 is turned into the female thread 201, the stopper 306 comes into contact with the front of the machine frame body 2, and when more force is applied to turn the cylinder 302 further, the elastic force of the stopper 306 is generated, increasing the frictional force and preventing the male thread 305 from rotating relative to the female thread 201. This prevents the ampoule 3 from becoming loose and also prevents accidents in which the ampoule 3 is ejected by the driving force of the piston.

[0041] 1-2-2. Piston As shown in Figure 1, a cylindrical piston syringe 4 is attached to the machine frame body 2, and a piston 5 is provided inside it so as to be slidable back and forth. The piston 5 consists of a piston base 510 and a piston rod 520. The piston base 510 has a cylindrical shape, with its outer circumferential surface in contact with the inner circumferential surface of the piston syringe 4, and can slide back and forth inside the piston syringe 4. A groove (not shown) running in the front-to-back direction is provided on the inner circumferential surface of the piston syringe 4 as a piston guide, and a projection provided on the outer circumferential surface of the piston base 510 slides along the piston guide, preventing the piston base 510 from rotating. The piston base 510 is provided with a protruding piston follower 511, which can receive a forward force from the elastic body (coil spring) 6. In addition, the piston follower 511 can receive a rearward force from the cam 750 of the elastic body energy storage unit 7, which causes the piston base 510 to move backward. Multiple washers 512 can be attached to the piston base 510 adjacent to the piston follower 511, and the injection force (injection pressure) can be adjusted by changing the length of the elastic body (coil spring) 6 when the piston base is moved backward. Since the elastic body (coil spring) 6 is compressed between the washers 512 and the machine frame body 2, when the piston base is moved backward by a certain distance, the more washers 512 there are, the more the elastic body (coil spring) 6 is compressed and the shorter its length becomes, so that more elastic energy can be stored and the injection force (injection pressure) can be increased.

[0042] The piston base 510 and the piston rod 520 are connected by the screwing of the female thread 513 on the piston base 510 and the male thread 521 on the piston rod 520. Therefore, the piston rod 520 can receive a forward force from the piston base 510, which is subjected to force from the elastic body (coil spring) 6. Since the piston head 522 is provided at the front end of the piston rod 520, the forward force applied by the elastic body (coil spring) 6 is also transmitted to the piston head 522. In Figure 1, the "forward direction" is indicated by the direction of the arrow. Therefore, when the piston base 510 is driven forward by the force of the elastic body (coil spring) 6, the piston head 522 presses against the plunger 304, allowing the injection solution 301 in the ampoule 3 to be ejected from the discharge nozzle 303.

[0043] Since the piston base 510 and the piston rod 520 are connected by a female thread 513 and a male thread 521, their relative positions can be changed forward or backward by rotating the piston base 510 and the piston rod 520 relative to each other. This allows the position of the piston head 522 to be adjusted forward or backward. In the first embodiment, the piston base 510 is provided with a piston guide (not shown) to prevent the piston base 510 from rotating, while the piston rod 520 can rotate due to the driving force of the second actuator (motor) 10. However, the present invention is not limited to this embodiment, and a structure in which the piston rod does not rotate and the piston base rotates is also possible. Furthermore, as described above, in the present invention, any structure is acceptable as long as the piston rod can receive a forward force from the piston base and is connected to the piston base in a way that allows its relative front-to-back position to be changed.

[0044] 1-2-3. Elastic energy storage section As shown in Figure 1, the needleless syringe 1 of the present invention is equipped with an elastic energy storage section 7, in which the cam 750 of the elastic energy storage section 7 presses against the piston follower 511, moving the piston base 510 backward and compressing the elastic body (coil spring) 6 to store energy. The elastic energy storage unit 7 includes a rod 710, a ball bearing 720, a large gear 730, a base 740, and a cam 750. Rod 710 is a cylindrical component that serves as the axis of rotation for the large gear 730. Rod 710 is hollow, allowing the piston rod 520 to move freely back and forth within its space. Rod 710 is inserted into a cylindrical ball bearing 720 and rotates smoothly because it contacts the inner surface of the ball bearing 720 via the balls. The large gear 730 is connected to rod 710, and the large gear 730 rotates around rod 710 as its axis of rotation. Both rod 710 and the large gear 730 rotate around the axis in the front-to-back direction on which the piston slides. Because the ball bearing 720 contacts the large gear 730 via the balls, the large gear 730 can also rotate smoothly without experiencing significant friction. The large gear 730 is provided with an annular base 740, and a cam 750 is provided on the surface of the base 740. As a result, the cam 750 also rotates around the axis in the front-to-back direction.

[0045] The large gear 730 can rotate by receiving the driving force of the first actuator (motor) 8. That is, the rotational driving force of the first actuator (motor) 8 is transmitted to the large gear 730 by a gear 810 provided on the shaft 820 of the first actuator (motor) 8.

[0046] To explain the transmission of driving force by gears, Figure 2(A) shows a cross-sectional view in a plan view including the dashed line C1-C2 in Figure 1. As shown in Figure 2(A), the rod 710 is cylindrical and has a space inside that allows the piston rod 520 to move freely. A large gear 730 is connected to the rod 710, and a large number of teeth 731 are provided on the outer circumference of the large gear 730. A gear 810 for rotating the large gear 730 is installed on top of the large gear 730, and rotates around the shaft 820 by the driving force of the first actuator (motor) 8. Numerous teeth 811 are provided on the outer circumference of the gear 810. When gear 810 rotates clockwise, at the point where gear 810 and the large gear 730 mesh, the teeth 811 of gear 810, which move to the left, press the teeth 731 of the large gear 730 to the left, causing the large gear 730 to rotate counterclockwise. Conversely, when gear 810 rotates counterclockwise, the large gear 730 rotates clockwise. The drive of the first actuator (motor) 8 is controlled by the control unit 11, which allows for flexible control of the rotation of the large gear 730.

[0047] As shown in Figure 2(A), the large gear 730 and the gear 810 are housed inside the cylindrical machine frame body 2, which prevents accidents such as being caught in the gears. The lower part of the machine frame body 2 has a flat shape, allowing the needleless syringe 1 to be stably placed on a workbench or the like. The machine frame body 2 is connected to its left and right sides by fastening screws (not shown), and by removing the fastening screws, internal parts can be replaced or repaired.

[0048] The cam 750 shown in Figure 1 is a mechanism that can convert the rotational motion of the large gear 730 into the forward and backward motion of the piston. As shown in Figure 1, the cam 750 is in contact with the piston follower 511 of the piston base 510. The cam 750 has a semi-annular three-dimensional shape with varying thicknesses in different locations. Since the piston follower 511 is in contact with the cam 750 via balls, the cam 750 can rotate smoothly, and since the piston base 510 is prevented from rotating by a piston guide (not shown), the point where the cam 750 and the piston follower 511 are in contact moves on the cam 750. As the cam 750 rotates, the thickness of the cam 750 in the front-rear direction at the point of contact with the piston follower 511 changes, thereby converting rotational motion into front-rear motion.

[0049] Figure 3 shows the state in which the cam 750 and the piston follower 511 are in contact, as well as the change in the thickness of the cam. Figure 3(A) is a schematic diagram showing the state in which the cam 750 and the piston follower 511 are in contact, viewed from the rear along the axis on which the piston slides in Figure 1. As shown in Figure 3(A), the large gear 730 is provided with an annular base 740, and a cam 750 is provided on the surface of the base 740. The cam 750 is a semi-annular three-dimensional shape with varying thickness, and a pair of identical cams 750 are formed on the base 740 at angles of 180° apart. A pair of piston followers 511, located at the tip of the piston base 510, contact the cam 750, and the piston followers 511 are pressed against the cam 750 by an elastic body (coil spring) 6. As a result, the piston base 510 moves back and forth according to the thickness of the cam at the point where it contacts the cam 750 and the piston follower 511. When the piston base 510 moves back and forth, the piston rod 520 connected to the piston base 510 also moves back and forth. There are two points where the cam 750 and the piston follower 511 make contact. However, since the two cams 750 have the same three-dimensional shape, the thickness of the cam 750 at the points where it contacts the piston follower 511 is the same at both locations. The thickness of the cam 750 at the point where it contacts the piston follower 511 changes with the rotation of the large gear 730. The angle of rotation of the large gear 730 is denoted by the symbol θ.

[0050] Figure 3(B) is a graph showing the change in the thickness of the cam 750 at the point where it contacts the piston follower 511 when the large gear 730 rotates. As shown in Figure 3(B), when the rotation angle θ of the large gear 730 is 0°, the thickness of the cam 750 is 0, and the piston follower 511 is in contact with the base 740. When the large gear 730 rotates to a rotation angle θ = 15°, the piston follower 511 first comes into contact with the cam 750, and as the rotation angle increases further, the thickness of the cam 750 at the point where it contacts the piston follower 511 increases. Finally, when the rotation angle reaches θ = 150°, the thickness of the cam 750 reaches its maximum value of G. Figure 3(A) shows the state when the rotation angle θ of the large gear 730 is 150°. As the thickness of the cam increases in this way, the piston base 510 moves backward, compressing the elastic body (coil spring) 6, which allows the elastic body energy storage section 7 to store energy in the elastic body.

[0051] As shown in Figure 3(B), as the rotation angle is further increased, the thickness of the cam 750 rapidly decreases to zero when the rotation angle θ = 165°. In this way, the cam 750 has a stepped shape, and the piston follower 511 drops sharply from this step, receiving the force that returns the elastic body (coil spring) 6 to its original shape, accelerating and driving forward at high speed before stopping when it reaches the base 740. In this way, the elastic body energy storage section 7 can also release the elastic body (coil spring) 6, thereby driving the piston 5 forward at high speed. As described above, the elastic body energy storage unit 7 of the needleless syringe 1 of the first embodiment is a cam mechanism that can convert the rotational motion of the first actuator (motor) 8 into the forward and backward motion of the piston, and by continuing the rotational motion, the elastic body (coil spring) 6 can be continuously energized and released.

[0052] 1-2-4. Piston head stop position adjustment section As shown in Figure 1, the needleless syringe 1 of the present invention is equipped with a piston head stop position adjustment unit 9. The piston rod 520 is rotated using the driving force of a second actuator (motor) 10, and the piston head stop position is adjusted by changing the relative position of the piston rod 520 with respect to the piston base 510 back and forth. As shown in Figure 1, the piston head stop position adjustment unit 9 is a mechanism that includes an internal gear 910 and a ball bearing 920. The internal gear 910 is cylindrical and has multiple teeth 911 with a linear tooth trace extending in the front-rear direction, facing inward to form an internal gear. In contrast, the rear end of the piston rod 520 has multiple teeth 523 with a linear tooth trace extending in the front-rear direction, facing outward to form a spur gear, which meshes with the teeth 911 of the internal gear 910. The internal gear 910 is inserted into the ball bearing 920 so that it can rotate smoothly, and is also connected to the shaft 1001 of the second actuator 10 so that it can be rotated by the driving force of the second actuator 10. With this structure, the rotational driving force of the second actuator (motor) 10 can be transmitted to the spur gear of the piston rod 520 via the internal gear 910, thereby rotating the piston rod 520. The drive of the second actuator (motor) 10 is controlled by the control unit 11, and the rotation of the internal gear 910 can be freely controlled in either direction.

[0053] To explain the transmission of driving force by gears, Figure 2(B) shows a cross-sectional view in a plan view including the dashed line C3-C4 in Figure 1. As shown in Figure 2(B), the internal gear 910 is cylindrical and houses the piston rod 520 inside. Multiple teeth 911 are provided on the inside of the internal gear 910, and these teeth mesh with the teeth 523 provided on the outside of the piston rod 520. Therefore, when the internal gear 910 is rotated clockwise by the second actuator (motor) 10, the piston rod 520 also rotates clockwise. Conversely, when the internal gear 910 is rotated counterclockwise, the piston rod 520 also rotates counterclockwise. Since both the teeth 911 of the internal gear 910 and the teeth 523 of the piston rod 520 have tooth traces that extend in a straight line in the front-rear direction, the piston rod 520 can slide back and forth relative to the internal gear 910.

[0054] Next, as shown in Figure 1, the male screw 521 on the piston rod 520 is machined to be a right-hand thread. Therefore, when the internal gear 910 is rotated clockwise, the piston rod 520 also rotates clockwise and moves forward relative to the piston base 510. Conversely, when the internal gear 910 is rotated counterclockwise, the piston rod 520 also rotates counterclockwise and moves backward relative to the piston base 510. In the first embodiment, the male screw 521 is machined to be a right-hand thread, but in the needleless syringe of the present invention, it may be machined to be a left-hand thread. In this case, when the piston rod 520 is rotated counterclockwise, it moves forward relative to the piston base 510, and when it is rotated clockwise, it moves backward.

[0055] Figure 1 shows the state where the piston base 510 is moved backward by the cam 750, and the elastic body (coil spring) 6 is energized, and Figure 3(B) shows the state where the rotation angle θ = 150° of the large gear 730. If the large gear 730 is rotated further and the rotation angle exceeds 165°, as described above, the piston follower 511 drops sharply from the step of the cam 750, releasing the energy of the elastic body (coil spring) 6, and the piston 5 is driven forward at high speed, after which the piston follower 511 stops when it reaches the base 740. The position of the piston head 522 at this stopping point is the "piston head stopping position". In the case of Figure 1, the distance (gap) between the piston head 522 and the plunger 304 is G, but the height of the cam 750 is also G. Therefore, even if the elastic body (coil spring) 6 is released, the piston head stops at the end of the plunger 304, and the piston head 522 cannot press against the plunger 304.

[0056] Therefore, in order to press the plunger 304 and inject the injection solution 301, it is necessary to change the piston head stop position to a forward position. This position change can be performed by the piston head stop position adjustment unit 9. Specifically, the control unit 11 shown in Figure 1 controls the second actuator (motor) 10 to rotate the internal gear 910 clockwise by a predetermined amount (a predetermined number of rotations), thereby moving the piston rod 520 forward by a distance x. As a result, the piston head stop position can also be changed to a position moved forward by a distance x compared to the case in Figure 1. When moving the piston rod 520 forward by a distance x, the piston rod position sensor 1301, which is connected to the control unit 11 by an electrical communication line (not shown), detects the approach of the piston head 522, thereby measuring the position of the piston head 522 in real time. When the control unit 11 detects that the piston head 522 has moved forward beyond a predetermined position, it immediately stops the driving of the second actuator (motor) 10 and stops the movement of the piston rod 520. This prevents the piston rod 520 from moving forward beyond a distance x and injecting an excessive amount of liquid, and also prevents accidents such as the piston head 522 flying forward and damaging the ampoule 3 or the front end of the machine frame body 2 when the piston rod 520 moves too far forward.

[0057] Figure 4 shows the operation of the internal structure of needleless syringe 1 when the piston head stop position is changed and the elastic body is released. Figure 4(A) shows the state after the piston head has moved forward from the state in Figure 1. As shown in Figure 4(A), compared to Figure 1, the piston head 522 has moved forward by a distance x, and the distance (gap) with the plunger 304 has changed from G to Gx. On the other hand, the position of the piston base 510 has not changed, and the position of the piston rod 520 relative to the piston base 510 has changed forward by a distance x. Since Figure 4(A) is the state before the release of the elastic body (coil spring) 6, the position of the piston head 522 shown in Figure 4(A) is not the "piston head stop position" in this invention. However, since the piston head 522 has moved forward by a distance x, the position at which the piston head stops when the elastic body (coil spring) 6 is released and the piston is driven forward ("piston head stop position") has also changed forward by a distance x.

[0058] Figure 4(B) shows the state after the piston 5 has been driven forward by releasing the elastic body (coil spring) 6 from the state in Figure 4(A), and has then stopped. As shown in Figure 4(B), the thickness of the cam at the point where the piston follower 511 contacts it disappears, and the piston follower 511 contacts the base 740. This is the state in Figure 3(B) where the rotation angle θ of the large gear 730 is 180°. As mentioned above, when the rotation angle θ of the large gear 730 exceeds 165°, the piston follower 511 drops sharply from the step of the cam 750, the elastic body (coil spring) 6 is released, the piston 5 is driven forward at high speed, and then the piston follower 511 stops when it reaches the base 740. At this time, as shown in Figure 4(B), the piston head 522 collides with the plunger 304 at high speed, and the injection fluid 301 can be ejected at high speed from the discharge nozzle 303.

[0059] As shown in Figure 4(B), the needleless syringe 1 is equipped with a piston base position sensor 1302 connected to the control unit 11 by a telecommunications line (not shown). The piston base position sensor 1302 detects the approach of the piston follower 511 and measures the position of the piston follower 511 in real time. When the control unit 11 measures that the piston base 510 has moved forward to a position where the piston follower 511 contacts the base 740, it immediately stops driving the first actuator (motor) 8. This allows the rotation of the large gear 730 to be stopped at the correct position after injection is complete, and prevents accidents such as unintended next injections.

[0060] In Figure 4(A), a gap exists between the piston head 522 and the plunger 304. Therefore, in the initial stage of the release of the elastic body (coil spring) 6, the piston 5 is accelerated by the elastic body (coil spring) 6 without resistance and can collide with the plunger 304 at high speed. As a result, the plunger 304 also moves at high speed, and the piston head 522 pushes the plunger 304 in one swift motion, injecting the injection fluid 301 until the piston follower 511 reaches the base 740 and stops. Thus, the presence of the gap allows the piston head 522 to act like a hammer striking the plunger 304, enabling the injection fluid to be ejected at high speed, thus allowing the injection fluid to be injected subcutaneously. In Figure 4(A), the gap distance is Gx. However, the piston head 522 moves forward by the thickness of the cam G and stops, so as shown in Figure 4(B), the plunger 304 can be pushed in by a distance x. Therefore, by controlling the distance x by which the piston head 522 moves forward using the control unit 11, the amount of injection fluid per injection (x × cross-sectional area of ​​the injection fluid 301 in the ampoule 3) can be controlled. And by determining the amount of injection fluid per injection, the number of times the injection fluid 301 in a single ampoule 3 can be injected (length of the injection fluid 301 in the front-to-back direction in the ampoule 3 / x) is also determined.

[0061] Increasing the value of x, the distance the piston head 522 moves forward, increases the amount of injection fluid per injection. However, this also shortens the gap distance (Gx), reducing the distance the piston head 522 is accelerated over and weakening the initial impact force (injection pressure). Conversely, a smaller value of x results in a smaller amount of injection fluid per injection. However, this increases the gap distance (Gx), increasing the distance the piston head 522 is accelerated over and strengthening the initial impact force (injection pressure). In areas where the skin is elastic and easily bends, even if the initial impact force (injection pressure) is strong, if the amount of injected fluid is small, the amount of injected fluid will run out while the skin is bending, and the fluid will not penetrate the skin. Therefore, increasing the value of x increases the amount of injected fluid, which pushes the fluid further into the bent skin, thus enabling penetration. Conversely, in areas where the skin is taut and hard, even if the amount of injection fluid is large, if the initial impact force (injection pressure) is weak, it will not be able to penetrate the hard skin. Therefore, it is effective to increase the initial impact force (injection pressure) by reducing the value of x, thereby breaking through the hard skin and allowing the injection fluid to penetrate.

[0062] Due to the stored energy of the elastic body, the elastic body (coil spring) 6, which was compressed as shown in Figure 4(A), returns to its original state and lengthens as shown in Figure 4(B) when the elastic body is released. As shown in Figure 4(B), the piston follower 511 is stopped in contact with the base 740, so the piston 5 cannot move any further forward, and the plunger 304 cannot be pushed any further by the piston head 522. Therefore, after the injection of the injectable fluid is completed once, the needleless syringe 1 can be safely kept on standby without accidental injection by maintaining the state shown in Figure 4(B).

[0063] When injecting the next injection solution, the second injection can be performed by continuously carrying out the steps of accumulating energy in the elastic body as shown in Figure 1, changing the piston head stop position as shown in Figure 4(A), and releasing energy in the elastic body as shown in Figure 4(B) in a short period of time. In the second injection, the piston head 522 is positioned further forward x compared to Figures 1 and 4(A) and (B), and each step is performed with this position. Subsequent injections (third and subsequent injections) can also be performed using this series of steps. By repeating this series of steps multiple times, it becomes possible to repeatedly inject the solution from a single ampoule in multiple doses.

[0064] After all the injection fluid in ampoule 3 has been injected, the second actuator (motor) 10 is driven in reverse to rotate the internal gear 910 counterclockwise by a predetermined amount (a predetermined number of rotations), moving the piston rod 520 backward and returning it to its initial position. Then, the empty ampoule 3 is removed and a new ampoule 3 filled with injection fluid 301 is attached, making it possible to inject the injection fluid again. When moving the piston rod 520 backward to return it to its initial position, the piston rod position sensor 1301 measures the position of the piston rod 520 in real time. When it detects that the piston rod 520 has moved further backward than its initial position, the control unit 11 immediately stops driving the second actuator (motor) 10 to stop the backward movement of the piston rod 520. This prevents the piston rod 520 from moving too far backward, which could cause the rear end of the piston rod 520 to collide with the bottom of the internal gear 910 when the elastic body (coil spring) 6 is being energized, thus preventing damage to the parts.

[0065] 1-2-5. Control Unit As shown in Figure 1, the needleless syringe 1 of the first embodiment includes a control unit 11 that controls the driving of the first actuator (motor) 8 and the second actuator (motor) 10. Power and command signals for controlling the actuator are supplied from the control unit 11 to the first actuator (motor) 8 via a cable 1101. Similarly, power and command signals for controlling the actuator are supplied from the control unit 11 to the second actuator (motor) 10 via a cable 1102. Power is supplied to the control unit 11 from an external source via a power cable 14. The control unit 11 uses this external power to perform information processing and to supply power to the first actuator (motor) 8 and the second actuator (motor) 10.

[0066] The first actuator (motor) 8 and the second actuator (motor) 10 are equipped with a drive circuit, a control circuit, and a rotational speed detector (not shown). The control circuit generates a drive voltage signal by calculating the voltage required to adjust the current rotational speed of the motor per unit time, which can be determined from the detection signal, to the rotational speed per unit time instructed by the command signal, based on the command signal supplied from the control unit 11 and the detection signal measured by the rotational speed detector, and supplies this drive voltage signal to the drive circuit. The drive circuit drives the actuator by applying voltage to the actuator based on the drive voltage signal received from the control circuit. The control unit 11 generates a command signal using an information processing device (not shown). The information processing device performs predetermined information processing according to the instructions of a control program stored in a storage device (not shown) and generates a command signal.

[0067] In the first embodiment, the control unit 11 supplies command signals to the first actuator (motor) 8 and the second actuator 10 to control the driving of these actuators. However, the needle-free syringe or needle-free injection system, driving method, and control program of the present invention are not limited to this embodiment. For example, the driving of the actuators may be controlled by supplying a voltage-controlled current to the actuators from the control unit 11. Furthermore, in the first embodiment, the control unit 11 generates command signals using an information processing device and a control program. However, the needle-free syringe or needle-free injection system and driving method of the present invention are not limited to this embodiment. For example, the actuators may be controlled using only a control circuit and a driving circuit without using an information processing device or a control program.

[0068] As shown in Figure 1, the control unit 11 is equipped with an injection button 1201 and an injection volume switching switch 1202 as interfaces that allow the user to operate and configure the needleless syringe 1. When the user presses the injection button 1201, the control unit 11, upon receiving the signal, drives the first actuator (motor) 8 and the second actuator (motor) 10 to perform the following steps 1A) to 1C) in quick succession. 1A) A step of storing energy in the elastic body (coil spring) 6 by driving the first actuator (motor) 8 to move the piston base 510 backward using the elastic body energy storage unit 7; 1B) A step in which the second actuator (motor) 10 is driven to move the relative position of the piston rod 520 with respect to the piston base 510 by a distance x in the forward direction using the piston head stop position adjustment unit 8; 1C) The first actuator (motor) 8 is further driven to release the elastic body (coil spring) 6 by the elastic body energy storage unit 7, thereby driving the piston 5 forward, pressing the plunger 304 with the piston head 522, and injecting the injection solution 301 in the ampoule 3; In this way, the user can automatically inject the solution with a simple operation of pressing the injection button 1201 of the needleless syringe 1. Furthermore, by pressing the injection button 1201 multiple times, the user can repeatedly inject the solution, making it possible to inject the injection solution from a single ampoule in multiple doses. In addition, by pressing the injection button 1201 multiple times in succession each time the injection solution is injected, the user can easily and automatically inject the solution in rapid succession using the actuator's driving force, without having to repeatedly compress the elastic body (coil spring) 6 manually.

[0069] The control unit 11 can receive a signal that the user has pressed the injection button 1201 and simultaneously execute steps 1A) and 1B) described above. This reduces the time required for injection. Here, in step 1A) above, the piston base 510 is moved backward by the elastic energy storage unit 7 shown in Figure 1, while in step 1B) above, the piston head stop position adjustment unit 8 moves the relative position of the piston rod 520 with respect to the piston base 510 forward. Therefore, if the speed at which the piston rod 520 moves forward relative to the piston base 510 in step 1B) is faster than the speed at which the piston base 510 moves backward in step 1A), then when steps 1A) and 1B) are performed simultaneously, the piston head 522 may move forward and press against the plunger 304, causing the injection fluid 301 to leak before injection. To prevent this, the control unit 11 drives the first actuator (motor) 8 and the second actuator (motor) 10 such that the speed at which the piston rod 520 moves forward relative to the piston base 510 in step 1B) is slower than the speed at which the piston base 510 moves backward in step 1A). Alternatively, the piston rod position sensor 1301 may measure the position of the piston rod 520 in real time, and when it detects that the piston rod 520 has moved forward beyond a predetermined position, the control unit 11 may immediately stop driving the second actuator 10.

[0070] The user can set the amount of injection per injection to either "0.05 ml" or "0.1 ml" using the injection volume selector switch 1202. If the amount of injection fluid per injection is set to "0.05 ml", then in step 1B) above, the distance x that changes the piston head stop position to the forward position is "x (cm) = 0.05 ml (cm 3 ) / Cross-sectional area of ​​injection solution 301 (cm²) 2The setting is changed to "). The drive amount of the second actuator (motor) 10 is controlled so that the distance x is set in this way, and the piston head stopping position is changed to a forward position. As a result, when the elastic body (coil spring) 6 is released, the piston head 522 pushes the plunger 304 into the ampoule 3 by a distance x, and the amount of injection fluid injected is 0.05 ml (= x × cross-sectional area of ​​the injection fluid 301). Since the amount of injection fluid filled in the ampoule is 0.4 ml, 8 injections can be performed. If the amount of injection solution per injection is set to "0.1 ml", then the distance x is "x (cm) = 0.1 ml (cm)". 3 ) / Cross-sectional area of ​​injection solution 301 (cm²) 2 When set to "0.05ml", the plunger 304 is pushed in twice as far as when the injection volume is set to "0.05ml", resulting in an injection volume of "0.1ml". The number of injections that can be performed is 4, which is half the number of injections compared to when the injection volume per injection is set to "0.05ml".

[0071] 1-2-6. Control Program In the control unit 11 of the needleless syringe 1 of the first embodiment, the " 1-2-5. system The Lord As explained in the section, the information processing device performs predetermined information processing and generates a command signal according to the instructions of the control program. Specifically, the control program causes the information processing device to perform information processing that includes the following steps 1A') to 1C') as essential steps. 1A') A step of generating a command signal to drive the first actuator (motor) 8 by a predetermined amount (a predetermined number of rotations) in order to store energy in the elastic body (coil spring) 6; 1B') A step of generating a command signal to drive a second actuator (motor) 10 by a predetermined amount (predetermined rotational speed) in order to change the piston head stop position to a forward position by a predetermined distance x; 1C') A step of generating a command signal to drive the first actuator (motor) 8 by a predetermined amount (a predetermined number of rotations) in order to release the elastic body (coil spring) 6;

[0072] The control program in the first embodiment includes, in part, an injection control program that controls the operation of injecting the injection solution in response to the user's operation of the injection button. More specifically, this injection control program causes the information processing device to execute the information processing shown in the flowchart in Figure 5. As shown in Figure 5, the information processing flow by the injection control program in the first embodiment begins with "Start". When the power cable 14 of the needleless syringe 1 shown in Figure 1 is plugged into a power outlet (not shown) and the start button (not shown) is pressed, the information processing device provided in the control unit 11 starts up and begins information processing by the injection control program.

[0073] The first step S01 of the information processing flow shown in Figure 5 is a step in which information processing is performed to detect the operation of the injection button 1201 by the user. In the information processing of step S01, if there is no signal that the injection button 1201 has been pressed (in the case of "No"), the detection is repeated and the system waits. If a signal that the injection button 1201 has been pressed is received (in the case of "Yes"), the system proceeds to the next step S02A. Step S02A is an essential step corresponding to 1A') described above, and is an information processing step that generates a command signal to drive the first actuator (motor) 8 by a predetermined amount (a predetermined number of rotations) in order to store energy in the elastic body (coil spring) 6. Here, the predetermined amount (predetermined rotational speed) for driving the first actuator (motor) 8 is the number of rotations of gear 810 required to rotate the large gear 731 shown in Figure 2(A) by 180°. The command signal is a signal that commands the number of rotations of the motor per unit time. By generating this command signal for a predetermined time and transmitting it to the first actuator (motor) 8, it becomes possible to drive it by the predetermined amount (predetermined rotational speed). As shown in Figure 5, step S02A generates a command signal, and when the transmission of the command signal to the first actuator (motor) 8 begins, the first actuator (motor) 8 starts to drive. After generating the command signal in step S02A and starting the transmission of the command signal, the process proceeds to the next step S03B.

[0074] Step S03B, shown in Figure 5, is an essential step corresponding to step 1B') described above, and is an information processing step that generates a command signal to drive the second actuator (motor) 10 by a predetermined amount (a predetermined number of rotations) in order to change the piston head stop position to a forward position by a predetermined distance x. Here, the distance x is the aforementioned " 1-2-5. Control Unit As explained in the section, the amount of injection fluid per injection is determined by whether it is set to "0.05 ml" or "0.1 ml", resulting in different values. When the internal gear 910 shown in Figure 1 is rotated clockwise, the piston rod 520 also rotates clockwise, causing the piston rod 520 to move forward relative to the piston base 510. The number of rotations of the internal gear 910 required to move forward by a distance x is the "determined amount (predetermined number of rotations)" in step S03B. Therefore, in step S03B, the set value of the amount of injection fluid per injection is read from the storage device, information processing is performed to identify the required number of rotations of the internal gear 910 corresponding to that set value, and then information processing is performed to generate a command signal. The command signal is a signal that commands the motor's rotational speed per unit of time. In step S03B, this command signal is generated for a predetermined time and transmitted to the second actuator (motor) 10, enabling driving by a predetermined amount (predetermined rotational speed). As shown in Figure 5, step S03B generates a command signal, and when the transmission of the command signal to the second actuator (motor) 10 begins, both the first actuator (motor) 8 and the second actuator (motor) 10 are driven, and the energy accumulation of the elastic body (coil spring) 6 and the forward position change of the piston head stop position proceed simultaneously. After generating a command signal in step S03B and starting to transmit the command signal, the process proceeds to the next step S041.

[0075] Steps S041, S051, S042, and S052 shown in Figure 5 are steps for performing information processing to determine the timing for stopping the driving of the first actuator (motor) 8 and the second actuator (motor) 10. Step S041 performs information processing to determine whether the first actuator (motor) 8 is being driven by a predetermined amount (a predetermined rotational speed). Specifically, the information processing determines whether a predetermined time has elapsed since the command signal generated in step S02A was transmitted to the first actuator (motor) 8. If the predetermined time has not elapsed, the determination is "Yes" because it is "not being driven by a predetermined amount (a predetermined rotational speed)", and the process proceeds to step S051. Conversely, if the predetermined time has elapsed, the determination is "No" because it is "being driven by a predetermined amount (a predetermined rotational speed)", and the process proceeds to step S061, where the generation of the command signal to drive the first actuator (motor) 8 is stopped. As a result, the driving of the first actuator (motor) 8 is stopped. Step S051 is an information processing step in which the second actuator (motor) 10 is driven by a predetermined amount (a predetermined rotational speed) or the piston head 522 has moved a distance x in the forward direction. Specifically, the information processing determines whether a predetermined time has elapsed since the command signal generated in step S03B was transmitted to the second actuator (motor) 10. At the same time, based on the position information of the piston head 522 measured by the piston rod position sensor 1301 shown in Figure 1, the distance the piston head 522 has moved in the forward direction is calculated compared to before the command signal to drive the second actuator (motor) 10 was generated, and the information processing determines whether that value has reached x. If it is determined that the second actuator (motor) 10 has not been driven by a predetermined amount (a predetermined rotational speed) and the piston head 522 has not moved a distance x in the forward direction, as shown in Figure 5, then "No" is determined and the process returns to step S041. Otherwise, that is, if it is determined that the second actuator (motor) 10 is driven by a predetermined amount (a predetermined number of rotations), or if it is determined that the piston head 522 has moved forward by a distance x, then the result is "Yes", and the process proceeds to step S071, stopping the generation of a command signal to drive the second actuator (motor) 10. As a result, the driving of the second actuator (motor) 10 is stopped. As described above, the information processing in steps S041 and S051 is repeated until either the first actuator (motor) 8 or the second actuator (motor) 10 is stopped.

[0076] If the drive of the first actuator (motor) 8 is stopped in step S061 as shown in Figure 5, the process proceeds to the next step S052, where a determination is made using the same information processing as in step S051. If the determination in step S052 is "Yes", the process proceeds to step S072, where the generation of the command signal for driving the second actuator (motor) 10 is stopped. As a result, the drive of the second actuator (motor) 10 is stopped, and the drive of both the first actuator (motor) 8 and the second actuator (motor) 10 is stopped. On the other hand, if the second actuator (motor) 10 is stopped first in step S071, the process proceeds to the next step S042, where a determination is made using the same information processing as in step S041. If the determination in step S042 is "Yes", the process proceeds to step S062, where the generation of the command signal to drive the first actuator (motor) 8 is stopped. As a result, the driving of both the first actuator (motor) 8 and the second actuator (motor) 10 is stopped.

[0077] As described above, steps S041, S051, S042, and S052 allow for the appropriate determination of the timing for stopping the driving of the first actuator (motor) 8 and the second actuator (motor) 10. This makes it possible to stop the driving of the first actuator (motor) 8 when the energy storage of the elastic body (coil spring) 6 is complete, and to stop the driving of the second actuator (motor) 8 when the piston head stopping position has been changed by a predetermined distance x to a forward position. In the injection control program of the first embodiment, as shown in steps S051 and S052, it is determined whether the piston head 522 has moved forward by a distance x based on the position information of the piston head 522 measured by the piston rod position sensor 1301. However, this determination is not essential; even if only it is determined whether the second actuator (motor) 10 has been driven by a predetermined amount (a predetermined number of rotations), the timing for stopping the second actuator (motor) 10 can be appropriately determined. In the injection control program of the first embodiment, by adding a determination based on the position information measured by the piston rod position sensor 1301 in addition to this determination, a double determination is made to prevent accidents such as the piston head 522 flying forward and damaging the ampoule 3 or the front end of the machine frame body 1 during injection, thereby enhancing the safety of the needleless syringe 1.

[0078] After stopping the driving of both the first actuator (motor) 8 and the second actuator (motor) 10 in step S062 or step S072 shown in Figure 5, the process proceeds to step S08C. Step S08C is an essential step corresponding to 1C') described above, and is the step of generating a command signal to drive the first actuator (motor) 8 by a predetermined amount (a predetermined number of rotations) in order to release the elastic body (coil spring) 6. Here, the predetermined amount (predetermined rotational speed) for driving the first actuator (motor) 8 is the number of rotations of gear 810 required to rotate the large gear 730 shown in Figure 2(A) by 180°. The command signal is a signal that commands the number of rotations of the motor per unit time. By generating this command signal for a predetermined time and transmitting it to the first actuator (motor) 8, it becomes possible to drive it by the predetermined amount (predetermined rotational speed). After generating the command signal in step S08C and starting to transmit the command signal, the process proceeds to the next step S09.

[0079] Step S09, shown in Figure 5, is a step for performing information processing to determine the timing for stopping the drive of the first actuator (motor) 8. In step S09, information processing is performed to determine whether the first actuator (motor) 8 has been driven by a predetermined amount (a predetermined number of rotations) or whether the piston follower 511 has come into contact with the base. Specifically, the information processing involves determining whether a predetermined time has elapsed since the command signal generated in step S08C was transmitted to the first actuator (motor) 8. Simultaneously, based on the position information of the piston follower 511 measured by the piston base position sensor 1302 shown in Figure 1, the information processing determines whether the piston follower 511 has reached the position where it contacts the base 740. If the information processing in step S09 determines that the first actuator (motor) 8 has not been driven by a predetermined amount (a predetermined number of rotations) and the piston follower 511 has not reached the position where it contacts the base 740 (i.e., "No"), the information processing in step S09 is repeated. In all other cases, that is, when it is determined that the first actuator (motor) 8 has been driven by a predetermined amount (a predetermined number of rotations), or when it is determined that the piston follower 511 has reached a position where it contacts the base 740, the system determines "Yes" and proceeds to step S10, stopping the generation of a command signal to drive the first actuator (motor) 8. This allows the driving of the first actuator (motor) 8 to be stopped at an appropriate timing when the injection of the injectable fluid 301 by the release of the elastic body (coil spring) 6 is complete.

[0080] In the injection control program of the first embodiment, as described above, in step S09, it is determined whether the piston follower 511 has reached a position where it contacts the base 740, based on the position information of the piston follower 511 measured by the piston base position sensor 1302. However, this determination is not essential; even if only it is determined whether the first actuator (motor) 8 has been driven by a predetermined amount (a predetermined number of rotations), the timing for stopping the first actuator (motor) 8 can be appropriately determined. In the injection control program of the first embodiment, in addition to this determination, a determination based on the position information measured by the piston base position sensor 1302 is also added to create a double determination, thereby preventing accidents such as the large gear 730 shown in Figure 4 continuing to rotate after the injection is completed, which could lead to an unintended next injection, and thus enhancing the safety of the needleless syringe 1.

[0081] After stopping the drive of the first actuator (motor) 8 in step S10 shown in Figure 5, the process proceeds to the next step S11, where information processing is performed to add 1 to the value of the variable s which counts the number of injections. The variable s, which counts the number of injections, is stored in the information storage device of the control unit 11. Variable s is used to count and display the number of injections. Specifically, an injection count display program, which is part of the control program, reads variable s and displays the number of injections since a new ampoule was set up to the present on a liquid crystal display device (not shown) of the needleless syringe 1, along with the number of injections that can be administered with a single ampoule ("8 times" or "4 times"). This allows the user to understand the number of injections administered to the patient and the remaining number of injections that can be administered with the same ampoule. Furthermore, the variable s is also used for information processing necessary for post-injection operations. Specifically, when the information processing in step S11 shown in Figure 5 is completed and the program reaches "End," if the variable s has not reached the number of injections possible with a single ampoule, the injection control program returns to "Start" in the flowchart and restarts the information processing flow. On the other hand, when the variable s reaches the number of times that can be injected with a single ampoule, the initialization program, which is part of the control program, drives the second actuator (motor) 10 shown in Figure 1 in reverse rotation to move the piston rod 520 backward to return it to its initial position, and performs information processing to set the value of variable s to 0. By driving the needleless syringe 1 through the above information processing, it becomes possible to repeatedly inject the injection solution 301 in a single ampoule 3 in multiple portions.

[0082] 1-3. Second Embodiment Figure 6 is a schematic diagram showing a needle-free injection system according to a second embodiment of the present invention. As shown in Figure 6, the needle-free injection system 1S of the second embodiment is a system consisting of a combination of multiple devices such as a multi-step injector 1U, a control box 11B, a foot switch 15, and components that connect them.

[0083] The multi-step injector 1U, like the needleless syringe 1 of the first embodiment shown in Figure 1, has a piston, an elastic body (coil spring), an elastic body energy storage unit, a first actuator (motor), a piston head stop position adjustment unit, and a second actuator (motor) inside the machine frame body, and an ampoule can be attached to the front of the machine frame body. However, the multi-step injector 1U does not have a control unit inside, but the control unit is provided inside a separate device called a control box 11B. The code 1103 connecting the control box 11B and the multi-step injector 1U supplies power to the multi-step injector 1U and enables electrical communication between the first and second actuators (motors) and various sensors located inside the multi-step injector 1U and the control unit located inside the control box 11B. The control unit located inside the control box 11B controls the driving of the first and second actuators (motors), similar to the control unit of the needleless syringe in the first embodiment, to operate the multi-step injector 1U, thereby enabling the injection solution in a single ampoule to be repeatedly injected in multiple stages. The code 1104 connecting the control box 11B and the foot switch 15 enables electrical communication between the control unit located inside the control box 11B and the foot switch 15. In the needleless syringe of the first embodiment, the injection solution is automatically injected when the user presses the injection button, but in the needleless injection system 1S of the second embodiment, the injection solution is automatically injected from the multi-step injector 1U when the user steps on the foot switch 15. The multi-step injector 1U is heavy and requires both hands to lift, but the use of the foot switch 15 makes the injection operation easier.

[0084] As shown in Figure 6, the control box 11B is equipped with a power switch 1105, which, when switched ON, can supply power to the multi-step injector 1U and the control unit located inside the control box 11B. Furthermore, the control box 11B is equipped with a touch panel 1106, which displays various information necessary for the user and enables user operation through the touch panel 1106. The touch panel 1106 displays the number of times the injection solution can be dispensed from a single ampoule as the "set number," and the number of times the injection solution has been dispensed after the ampoule has been replaced as the "operation number." This allows the user to understand the number of injections administered to the patient and the remaining number of injections that can be dispensed from the same ampoule.

[0085] As shown in Figure 6, the upper left part of the touch panel 1106 reads "0.4ml 8 shot" The setting conditions are displayed. Here, "0.4ml" is the initial value of the injection solution in the ampoule. This indicates that the volume is 0.4 ml, and "8 shots" refers to the number of times the injection solution in one ampoule can be dispensed. This indicates that the number is 8. These settings can be changed by the user pressing the "Settings" button located in the lower left part of the touch panel 1106. When the user presses the "Settings" button, the screen of the touch panel 1106 switches to a setting selection screen (not shown), and the user can change the setting by touching the setting options displayed on the setting selection screen. If the initial value of the amount of injection fluid in the ampoule differs, the initial position of the plunger that pushes out the injection fluid from the ampoule will also differ. If the position of the piston rod (piston head) is not initialized to match that position, a "dry firing" may occur where the injection fluid is not injected even when the injection operation is performed. In addition, when attaching the ampoule to the front end of the multi-step injector 1U, the plunger may be pressed by the piston head, causing the injection fluid to leak. Therefore, the control unit inside the control box 11B initializes the position of the piston rod (piston head) according to the initial value of the amount of injection fluid in the ampoule set by the user. Furthermore, the control unit located inside the control box 11B adjusts the amount of injection fluid per injection by changing the distance the piston head stops forward after each injection, according to the number of injections the user has set, thereby enabling injections to be made the number of times the user has set.

[0086] As shown in Figure 6, a vacuum attachment 1610 is mounted on the front end of the multi-step injector 1U. One end of a suction tube 1621 is attached to the vacuum attachment 1610, and the other end of the suction tube 1621 is attached to a suction device 1620. The suction device 1620 is located on top of the control box 11B and contains a vacuum pump that can suck air from inside the vacuum attachment 1610 through the suction tube 1621 to create a negative pressure lower than atmospheric pressure. To generate negative pressure using the suction device 1620, the "Suction" button displayed on the touch panel 1106 is touched to "ON," which starts suction by the vacuum pump of the suction device 1620.

[0087] Figure 7 is a schematic diagram showing the cross-sectional structure and usage method of the front end of a multi-step injector with a vacuum attachment. Figure 7(A) shows the state before the skin is attached to the vacuum attachment, and Figure 7(B) shows the state after the skin has been attached to the vacuum attachment. As shown in Figure 7(A), the vacuum attachment 1610 has a cylindrical shape with two open ends, and the inner diameter of the rear open end is slightly larger than the outer diameter of the front end of the machine frame body 2 of the multi-step injector 1U. This allows the rear open end of the vacuum attachment 1610 to be fitted into the front end of the machine frame body 2 of the multi-step injector 1U and attached detachably. An ampoule 3 is attached to the front end of the machine frame body 2, and a space is formed around the ampoule 3 by being surrounded by the vacuum attachment 1610.

[0088] Conventional needleless syringe attachments have a similar shape, and by attaching them to the front end of the needleless syringe and pressing the open end of the attachment firmly against the skin, loose skin can be taut, making it easier to inject the solution subcutaneously. However, there is a problem in that pressing the attachment firmly against the skin causes pressure pain to the patient, which was a major problem, especially when injecting into the delicate area of ​​the face.

[0089] The vacuum attachment 1610 used in the needleless injection system 1S of the second embodiment has a mounting port to which a suction tube 1621 can be attached, as shown in Figure 7(A). The suction tube 1621 is connected to the suction device 1620, and the vacuum pump provided in the suction device 1620 can suck air out, thereby reducing the pressure in the internal space surrounded by the vacuum attachment 1610. As shown in Figure 7(A), the surface of the skin 17 to which the injection solution 301 is injected is in a relaxed state. Even if the injection solution 301 is injected at high speed towards the skin 17, the relaxed skin 17 deforms significantly to receive it, absorbing the kinetic energy of the injection solution 301. Therefore, it may not be possible to inject the injection solution 301 subcutaneously.

[0090] Therefore, by bringing the open end of the vacuum attachment 1610, which has a reduced internal pressure, closer to the skin, the skin 17 is attracted to the vacuum attachment as shown in Figure 7(B). Furthermore, by sucking the skin 17 into the reduced-pressure interior of the vacuum attachment 1610, the slack skin 17 is pulled taut, making the surface of the skin 17 tightly taut. With the surface of the skin 17 tightly taut, the skin 17 is less likely to deform, so it cannot absorb the kinetic energy of the injection solution 301. Also, because the skin 17 is stretched by being pulled, the epidermis and dermis become thinner. Therefore, when the piston head 522 presses the plunger 304 to eject the injection solution 301 at high speed, the injection solution 301 can be injected subcutaneously and diffused subcutaneously.

[0091] As shown in Figure 7(B), the vacuum attachment 1610 is provided with an air vent 1611. This air vent 1611 can be used to adjust the reduced pressure inside the vacuum attachment 1610. As shown in Figure 7(B), when the air vent 1611 is blocked with a finger 18, the pressure inside the vacuum attachment 1610 can be strongly reduced, and the skin 17 can be drawn into the vacuum attachment 1610. After the subcutaneous injection of the injection solution 301 is complete, the pressure inside the vacuum attachment 1610 can be relieved by removing the finger 18 from the air vent 1611, and the suction of the skin 17 to the vacuum attachment 1610 can be released.

[0092] In the needle-free injection system 1S of the second embodiment, the control unit is located in a control box 11B, which is a separate device from the multi-step injector 1U shown in Figure 6. In the present invention, the invention is not limited to this embodiment, and a first actuator and / or a second actuator may also be located in the control box 11B. In this case, the first actuator and / or the second actuator may be a hydraulic actuator, a pneumatic actuator, or an actuator that transmits power by wire, and a path for oil, air, or wire is provided in the code 1103 to transmit the power generated by driving the actuator in the control box 11B to the elastic energy storage unit and / or piston head stop position adjustment unit in the multi-step injector 1U. With this configuration, the multi-step injector 1U held by the user can be made even lighter.

[0093] 2. Method for driving a needle-free syringe or needle-free injection system The driving method for the needle-free syringe or needle-free injection system of the present invention is the driving method described in [9] to

[13] above in the [Summary of the Invention]. The present invention provides a driving method for driving a needleless syringe or needleless injection system that utilizes an elastic body such as a spring. A) A step of storing energy in an elastic body using an elastic body energy storage unit that stores energy in an elastic body by moving a piston backward, and a first actuator that drives the elastic body energy storage unit, B) A piston head stop position adjustment unit that adjusts the piston head stop position at which the piston head stops when the stored energy elastic body is released and the piston is driven forward, and a second actuator that drives the piston head stop position adjustment unit, to change the piston head stop position to a forward position, C) By releasing the elastic body, the piston is driven forward, and the piston head of the piston presses against the plunger, thereby ejecting the injection fluid from the ampoule. It is characterized by repeatedly executing the following. By driving the needleless syringe or needleless injection system in this way, the plunger that pushes out the injection fluid from the ampoule is pressed forward in stages by the piston head, making it possible to repeatedly inject the injection fluid from a single ampoule in multiple doses.

[0094] In the driving method of the present invention, "repeated" means performing steps A) to C) multiple times until all of the injection solution in the ampoule is injected. Therefore, steps A) to C) may be performed multiple times in succession within a short period of time, or multiple injections may be performed with a long interval between injections. For details of the driving method of the present invention, see the above " 1. Needle-free syringe or needle-free injection system As described in detail in the chapter, the operation of each part of the needleless syringe or needleless injection system is explained in detail.

[0095] 3. Control Program The control program of the present invention is the control program described in

[14] to

[17] above in the [Summary of the Invention]. The control program of the present invention is a program that causes a control unit of the needle-free injector or needle-free injection system of the present invention to execute specific information processing. The control program of the present invention may be stored in a memory device of the needle-free injector or needle-free injection system, and by reading it, the information processing device of the control unit may be caused to execute the specific information processing described in the control program. Alternatively, the control program of the present invention may be stored in a server's memory device and downloaded to a mobile terminal or the like via the internet, thereby causing the mobile terminal or the like to function as the control unit of the needle-free injection system. The control program of the present invention is not limited to the above, but for example, the above 1―2 ―6. Control Program The control program of the present invention may include in part an injection control program that performs information processing in the flow shown in the section and Figure 5. 1-2-6. Control Program As illustrated in the section above, the injection control program may include programs that implement other functions, such as a program that displays the number of injections, in addition to the injection control program that controls the operation of injecting the injection solution. [Industrial applicability]

[0096] The needle-free syringe or needle-free injection system, as well as the driving method and control program for the needle-free syringe or needle-free injection system of the present invention, are inventions relating to medical, veterinary, or experimental equipment, and the driving method and control program for said equipment, and are not inventions relating to methods for treating or diagnosing humans; therefore, they are inventions that can be used industrially. [Explanation of symbols]

[0097] 1,1A needleless syringe 1S Needle-Free Injection System 1U Multi-Step Injector 2 aircraft frame main body 201 Female thread 3.3A Ampoule 301 Injection 302 cylinders 303 Discharge nozzle 303A Discharge port 304, 304A plunger 305 Male screw 306 Stopper 4-Piston Syringe 5.5A Piston 510 Piston base 511 Piston Follower 512 Washer 513 Female thread 520 Piston Rod 521 Male screw 522, 522A Piston Head 523 teeth 6. Elastic body (coil spring) 6A Spring 7 Elastic energy storage section 710 Rod 720 Ball bearing 730 Large Gear 731 teeth 740 base 750 Cam 8. First actuator (motor) 810 Gear 811 teeth 820 Shaft 9. Piston head stop position adjustment section 910 Internal gear 911 teeth 920 Ball bearing 10. Second actuator (motor) 11 Control Unit 11B Control Box 1101 Cable 1102 Cable 1103 Code 1104 Code 1105 Power switch 1106 Touch Panel 1201 Ejection Button 1202 Injection liquid volume selector switch 1210A Trigger 1211A Trigger Finger 1212A Push End 1220A Safety Lock 1301 Piston rod position sensor 1302 Piston base position sensor 14 Power Cables 15 Footswitch 1610 Vacuum Attachment 1611 Air vent 1620 Aspirator 1621 Suction tube 17 Skin 18 fingers

Claims

1. A needleless syringe or needleless injection system comprising a machine frame body to which an ampoule having a plunger for pushing out an internal injection solution can be attached to the front, a piston provided on the machine frame body so as to be slidable back and forth, and an elastic body that applies a forward force to the piston, wherein by releasing the stored energy of the elastic body to drive the piston forward, the piston head of the piston presses against the plunger and ejects the injection solution inside the ampoule, An elastic body energy storage unit that stores energy in the elastic body by moving the piston backward, A first actuator that drives the elastic energy storage unit, A piston head stop position adjustment unit adjusts the piston head stop position at which the piston head stops when the stored energy in the elastic body is released and the piston is driven forward, A second actuator that drives the piston head stop position adjustment unit, It comprises a control unit that controls the first actuator and the second actuator, The piston comprises a piston base to which a forward force is applied by the elastic body, and a piston rod equipped with the piston head. The piston rod is connected to the piston base so that it can receive a forward force from the piston base and can change its relative front-to-back position with respect to the piston base. The piston head stop position adjustment unit can adjust the piston head stop position by changing the relative position of the piston rod with respect to the piston base back and forth using the driving force of the second actuator. The control unit controls the driving of the first actuator and the second actuator, thereby accumulating energy in the elastic body by the elastic body energy storage unit, changing the piston head stop position forward by the piston head stop position adjustment unit, and driving the piston forward by releasing the energy of the elastic body. A needle-free syringe or needle-free injection system characterized by repeatedly performing the following.

2. It further has an interface for setting the number of injections per ampoule or the amount of injection solution per injection, The needleless syringe or needleless injection system according to claim 1, characterized in that the control unit controls the amount of drive of the second actuator according to the number of injections per ampoule or the amount of injection fluid per injection set by the user via the interface, thereby controlling the distance of the forward position change of the piston head stop position.

3. The piston rod and the piston base are connected to each other by a male thread and female thread structure. The needleless syringe or needleless injection system according to claim 1 or 2, characterized in that the piston head stop position adjustment unit rotates the piston rod and the piston base relative to each other by the driving force of the second actuator, thereby changing the position of the piston rod relative to the piston base in the forward and backward directions.

4. A spur gear having multiple teeth with a linear tooth trace extending in the front-rear direction is formed on the outer circumference of a portion of the piston rod. The piston head stop position adjustment unit has a cylindrical internal gear that is slidable back and forth relative to the spur gear and has multiple teeth on its inner circumference with tooth traces extending linearly in the front-rear direction, The needleless syringe or needleless injection system according to claim 3, characterized in that the rotational driving force of the second actuator can be transmitted to the spur gear via the internal gear to rotate the piston rod, regardless of the position of the piston rod which slides back and forth.

5. The elastic energy storage unit has a cam that can convert the rotational motion of the first actuator into the forward and backward motion of the piston. The cam is rotatably mounted around an axis in the front-rear direction on which the piston slides, and the thickness of the portion of the cam that contacts the piston in the front-rear direction changes with the rotation of the cam, thereby converting the rotational motion of the first actuator into the front-rear motion of the piston to store energy in the elastic body, as described in claim 1 or 2.

6. A vacuum attachment having a cylindrical shape with two open ends, one of which can be attached to the plunger or the front of the machine frame body to which the plunger is attached, and the other open end can be brought into contact with the skin, A suction device that can make the skin adhere tightly to the attachment by sucking the air inside the vacuum attachment, The needle-free syringe or needle-free injection system according to claim 1 or 2, further comprising the above.

7. A method for driving a needleless syringe or needleless injection system comprising a machine frame body to which an ampoule having a plunger for pushing out an internal injection solution can be attached to the front, a piston provided on the machine frame body so as to be slidable back and forth, and an elastic body that applies a forward force to the piston, wherein the elastic body, which has stored energy, is released to drive the piston forward, thereby pressing the plunger with the piston head and ejecting the injection solution in the ampoule, The needle-free syringe or needle-free injection system further includes: 1) An elastic body energy storage unit that stores energy in the elastic body by moving the piston backward, 2) A first actuator that drives the elastic energy storage unit, 3) A piston head stop position adjustment unit that adjusts the piston head stop position at which the piston head stops when the stored energy in the elastic body is released and the piston is driven forward, 4) A second actuator that drives the piston head stop position adjustment unit, 5) A control unit that controls the first actuator and the second actuator, It has, Under the control of the control unit, A) The first actuator drives the elastic body energy storage unit to store energy in the elastic body, B) The second actuator drives the piston head stop position adjustment unit to change the piston head stop position to a forward position, C) The first actuator drives the elastic body energy storage unit, thereby releasing the elastic body and driving the piston forward, so that the piston head of the piston presses against the plunger and injects the injection solution in the ampoule. A method for driving a needleless syringe or needleless injection system, characterized by repeatedly performing the following steps.

8. The method for driving a needleless syringe or needleless injection system according to claim 7, characterized in that, by the control of the control unit, in step B), the amount of drive of the second actuator is controlled according to the number of injections of the injection solution or the amount of injection solution per injection set by the user, thereby controlling the distance of the forward position change of the piston head stop position.

9. The method for driving a needleless syringe or needleless injection system according to claim 7, characterized in that the steps of A) and B) are executed simultaneously by the control of the control unit.

10. A method for driving a needleless syringe or needleless injection system according to claim 7 or 9, characterized in that steps A) and B) are performed immediately before the injection of the injection solution by the control of the control unit.

11. The control unit of the needleless syringe or needleless injection system described in claim 1 A') A step of generating a command signal to drive the first actuator by a predetermined amount in order to store energy in the elastic body, B') A step of generating a command signal to drive the second actuator by a predetermined amount in order to change the piston head stop position to a forward position, C') A step of generating a command signal to release the energy stored in the elastic body in order to release the energy stored in the elastic body. A control program characterized by causing it to perform information processing that includes such processing.

12. The control program according to claim 11, further characterized in that the control unit is instructed to perform information processing to determine a predetermined amount to drive the second actuator in step B') based on the number of injections of the injection solution or the amount of injection solution per injection set by the user.

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