JP2009247762A - Needleless injector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a needleless injector which can use gas pressure to suck/jet a drug liquid and is high in quantitativeness of the amount of the drug liquid to be injected. <P>SOLUTION: The needleless injector includes a cylinder body 4 in which a partition wall 4c is formed to have a communication hole 4b; a gas chamber 4e which is formed by screwing a cap 41 to the back end and is mounted with a pressure piston 52 sliding on the inner circumferential surface; a gas chamber 4d which is in front of the partition wall 4c and is equipped with a ball stopper 65 sliding on the inner circumferential surface; a gas supply/exhaust selector 7 for supplying/exhausting gas for the gas chamber 4d; and a gas supply/exhaust selector 8 for supplying/exhausting gas for the gas chambers 41a and 4e. A nozzle holder 3 is moved forward to suck a drug liquid Y from a drug vial B, and then a lever 71 is drawn to supply the gas chamber 4d with a high pressure gas G, and then the ball stopper 65 is moved forward and a latch is taken off, and then the pressure piston 52 is moved forward to jet the drug liquid Y. In order to suck a fresh drug liquid Y from the drug vial B again, the gas chamber 4e is supplied with the high pressure gas G, and the gas chamber 41a is exhausted of the high pressure gas G, and then the pressure piston 52 is moved backward. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a needleless syringe that performs injection by jetting a certain amount of a chemical solution sucked from an injection hole of a nozzle or a chemical solution filled in a nozzle with a gas pressure driven piston.

  A needleless syringe pushes a chemical solution in a nozzle that has been inhaled from the injection hole at the tip of the needle, or a chemical solution that has been filled in the nozzle with a piston, and jets the drug solution from the injection hole, so that the chemical solution is delivered to the patient (other than human). Syringes). In other words, since injection with a needleless syringe does not use an injection needle, there are advantages such as prevention of needle stick accidents and ease of use for patients with advanced phobia. For example, when a diabetic patient himself self-injects insulin on a daily basis. Are also used. In addition, it has been announced that it is used for gene drugs and has higher medicinal properties than syringes with needles.

  In a conventional needleless syringe, a type in which a piston 102 in a nozzle 101 having a structure as shown in FIG. 9 is advanced at high speed using a compression spring 103 as a power source is widely used (see Patent Document 1). The needleless syringe incorporates a front grip 104 in which a nozzle 101 having an injection hole 101a is incorporated, a latch mechanism 106 that latches or releases a piston rod 105 that connects the piston 102, and an injection button 107 that performs injection by releasing the latch. The rear grip 108 is configured to be screwed with a screw portion 109. A screw part 110 is provided at the front part of the piston rod 105, and a nut 111 for adjusting the compressive force to adjust the injection force of the chemical solution is screwed. Further, a flange ring 112 is integrally formed at the tip thereof. A compression spring 103 is attached through a piston rod 105 between the nut 111 and the rear inner wall of the rear grip 108.

When the rear grip 108 of the needleless syringe is rotated and moved forward, the piston rod 105 is latched by the latch mechanism 106 and the compression spring 103 is compressed. Due to this compression force, the moving force in the forward direction is exerted on the piston rod 105. Be energized. In this state, the nozzle 101 is brought into contact with a chemical vial (not shown), the rear grip 108 is retracted, and the chemical is sucked. When the injection button 107 is pushed while the nozzle 101 is pressed against the injection site to release the latch of the piston rod 105, the compression spring 103 is extended and the piston 102 is advanced to inject the drug solution.
Japanese Patent Laid-Open No. 2000-233021

  The conventional needleless syringe is configured as described above, but requires an operation of compressing the compression spring and latching the piston rod to the rear grip each time injection is performed, which is troublesome and powerful. Labor is required. In particular, when the operation of repeatedly injecting the same amount of drug solution is performed, a great physical burden is imposed on the user. In addition, since a strong compression spring is used, there is a problem that vibration and impact sound are generated due to an impact at the time of injection and handling is difficult.

  As a syringe to improve the problems of the compression spring type needleless syringe as described above, a needleless syringe using high pressure gas as the driving power source of the piston rod has been put into practical use. Since the piston rod starts to apply gas pressure to the piston rod, the piston rod starts to move slowly, and the drug solution leaks within the time required to reach the gas pressure that allows the drug solution to penetrate the skin smoothly, thus reducing the quantitativeness of the drug injection amount. There is a problem.

In order to achieve the above object, the needleless syringe of the present invention is a needleless syringe that presses with a piston having a pressure receiving portion to energize a liquid medicine and jets the nozzle to perform subcutaneous injection, and has the nozzle. A nozzle holder, and a partition wall connected to the nozzle holder and having a communication hole communicating in the front-rear direction, and forming first and second cylinder parts for housing the piston via the partition wall; A cylinder body that accommodates the piston pressure receiving portion; and a cylinder body that is disposed in the first cylinder portion, latches the pressurized piston, and includes a pressure receiving portion. A latch mechanism for releasing the latch by movement due to pressure, and a first mechanism for supplying and exhausting high-pressure gas to the first cylinder part, which is disposed in the cylinder body. A gas flow path, and a first gas switching means for switching supply / non-supply of the high-pressure gas from the high-pressure gas source to the first gas flow path and exhaust from the first gas flow path. .

  And a second gas passage for supplying and exhausting high pressure gas between the pressure receiving portion on the partition wall side of the partition wall and the piston in the second cylinder portion, and the high pressure gas source from the high pressure gas source. And a second gas switching means for switching between supply non-supply to the second gas flow path and exhaust from the second gas flow path.

  The latch mechanism according to the present invention includes an outer peripheral groove formed in the piston, a latch ball that fits into the outer peripheral groove, a latch ball receiver that accommodates the latch ball and is movable in the axial direction, and the first A compression mechanism comprising a ball retainer that slides in close contact with the cylinder and prevents the latch ball from coming out of the outer peripheral groove, a compression spring that abuts the ball retainer at one end, and a spring stopper that abuts the other end. The piston is latched by the movement of the ball press by the pressing of the spring, and the piston is unlatched by the high-pressure gas supplied to the front of the partition.

  A first gas switching means according to the present invention connects a stepped hollow hole formed in a grip disposed at a lower portion of a cylinder body, an intermediate portion of the stepped hollow hole, and a gas chamber in front of the partition wall. A rod having a gas flow path and an outer peripheral groove formed near the rear, a seal packing fitted in front of the gas flow path, and a stop valve fixed to the rear end in contact with the stepped hollow hole to block the flow path of the high pressure gas; A cap screwed to the rear end of the stepped hollow hole, a compression spring interposed between the cap and the stop valve, and supply or non-supply of high pressure gas to the gas chamber by pressing the rod And a switching lever for switching the exhaust, and when the second gas switching means is in a high pressure gas supply state, the high pressure gas is supplied to the gas chamber in front of the partition wall by pulling the switching lever and pressing the rod. Applied to the pressure receiving part. The ball presser is moved forward to start the piston, the switching lever is released and the rod is returned to shut off the supply of high pressure gas to the gas chamber, and the second gas switching means In the state, the high pressure gas is exhausted from the gas chamber by pulling the switching lever and pressing the rod.

  The second gas switching means according to the present invention includes a hollow hole having three inner circumferential grooves arranged in parallel at intervals in a grip disposed at a lower portion of the cylinder body, a front inner circumferential groove and the partition wall. A gas flow path for connecting the rear gas chamber, a gas supply port for supplying high-pressure gas to the inner peripheral groove of the intermediate portion, a gap for exhausting the high-pressure gas at the rear of the piston pressure receiving portion through the rear inner peripheral groove, A passage connecting port for supplying, non-supplying and exhausting high pressure gas to the gas chamber at the rear of the pressure receiving portion, and a passage connecting port for supplying and exhausting high pressure gas to the rear gas chamber of the stepped hollow hole, and two places A wide diameter stepped portion is arranged in parallel, a seal packing is fitted to the wide diameter stepped portion, a rod inserted in the hollow hole, and the rod is pressed to shut off the supply of high pressure gas to the gas chamber And a switching lever for releasing indoor gas, and pulling the switching lever to The high pressure gas is discharged, the high pressure gas is supplied to the gas chamber at the rear of the pressure receiving portion, the high pressure gas is supplied to the gas chamber at the rear of the partition wall by pushing the rod from the rear, and the rear of the pressure receiving portion is The room gas is exhausted.

The needleless syringe has a gas pressure applied to the piston from the beginning, so that the movement starts after the latch is released, and the gas pressure until it penetrates the skin reaches early, so that the leakage of the drug solution is also reduced. In addition, since a compression spring for driving the piston is not used, injection can be performed with a low gas pressure.
In addition, since the high-pressure gas supplied from the outside is used as a power source, the injection force can be changed only by changing the gas pressure, the adjustment range of the injection force can be widened, and it can be used for a wide range of applications.
In addition, since the needleless syringe can inhale chemicals using high-pressure gas as the power source, the operation of operating the front and rear grips to compress the compression springs and inhaling the chemicals every time of injection is omitted. Efforts can be saved if the dose is injected repeatedly.

  Embodiments of the needleless syringe of the present invention will be described below with reference to the drawings. FIG. 1: is the front view (A), AB sectional drawing (B), back view (C), and AC sectional drawing (D) which show the structure of the needleless syringe 1 by the Example of this invention.

  As shown in FIG. 1, the needleless syringe 1 of the present invention sucks a chemical solution, and has a nozzle 2 formed with an injection hole 2a for injecting the chemical solution and a hollow hole 2b for storing the inhaled chemical solution, screwed to the tip. And a nozzle holder 3 having an axial hollow hole 3a and a screw 3b formed on the outer peripheral surface of the rear portion thereof, and a female screw 4a for screwing with the nozzle holder 3 formed on the inner peripheral surface of the tip and the central portion. A partition wall 4c having a communication hole 4b is formed.

  The front and rear portions of the cylinder body 4 are used as a gas chamber 4d and a gas chamber 4e, and a cap 41 is screwed to the rear end with a screw 42, and the nozzle holder 3 and the chemical body press through the cylinder body 4 are pressed. A tool 5, a latch mechanism 6 for latching the chemical liquid pressing tool 5 to the cylinder body 4, and supply / discharge switching for switching between supply, non-supply, and exhaust of high-pressure gas for releasing the latched state and the latched state And a grip 9 that is screwed into the lower portion of the cylinder body 4 and is provided with a gas supply switching unit 8 that switches a supply destination of the high-pressure gas (supply / discharge switching unit 7, gas chambers 4e, 41a). ing. A high pressure gas G used as a power source for chemical injection is supplied to the joint 11 through the tube 10.

  The chemical pressing tool 5 is slid in close contact with the inner wall of the hollow hole 2b of the nozzle 2 by fitting the packing 51 and the pressure receiving piston 52 that slides in close contact with the inner wall of the gas chamber 4e. The piston 54 is configured to be connected to the piston 54 which is moved and moved, and the piston rod 56 which is connected with the stopper 55 and has an outer peripheral groove 56a.

  The latch mechanism portion 6 is formed with a plurality of latch balls 61, a screw 6a on the outer peripheral surface of the tip and a through hole 63a for moving each latch ball 61 in the circumferential direction behind the plurality of latch balls 61, A packing 63A for sealing between the piston rod 56 and a packing 63B for sealing between the partition wall 4c are fitted, and a ball receiver 63 screwed to the cylinder body 4 by a screw 62, and an outer periphery of the piston rod 56. The formed outer peripheral groove 56a, the packing 64 and the packing 64A, and a ball press 65 that slides in close contact with the inner wall of the gas chamber 4d, and a compression that applies a rearward biasing force to the ball press 65 The spring 66 is composed of a spring stopper 67 that abuts one end thereof.

  The supply / discharge switching unit 7 is fitted with a lever 71 for performing a switching operation of the injection or suction of a chemical solution and a packing 72 and screwed with a stop valve 75, and linked to the lever 71 to the gas chamber 4 d for high-pressure gas. An outer peripheral groove 73a for switching the suction or exhaust operation is formed, and an air supply / exhaust rod 73 that moves forward and backward in the stepped hollow hole 9f formed in the grip 9 and one end of the stepped hollow hole 9f are sealed. The cap 74, a compression spring 76 interposed between the cap 74 and the stop valve 75, and flow paths 9b and 9c communicating between the gas chamber 4d and the stepped hollow hole 9f.

  The gas supply switching unit 8 includes a lever 81 for performing a switching operation of a high-pressure gas supply direction, a gas supply / discharge chamber 8a formed as a stepped through hole in the grip 9, and the gas supply / discharge chamber 8a. The gas supply direction switching rod 82 for fitting the packings 82a, 82b, 82c, 82d, retreating in conjunction with the lever 81, and moving forward by pushing the rear end to switch the gas supply direction, and the gas It is comprised from the flow paths 9d and 9e which connect the supply / discharge chamber 8a and the said gas chamber 4e.

  The operation procedure from the inhalation of the drug solution to the injection by the needleless syringe 1 having the above configuration and the operation state thereof will be described in detail below with reference to FIGS. In addition, the components shown with the same code | symbol in FIGS. 1-8 have the same function. FIG. 2 is a cross-sectional view (A) when the lever 81 of the needleless syringe 1 is pulled back, and a partial LM cross-sectional view (B) thereof. FIGS. 3 to 7 are cross-sectional views showing the operation states of the needleless syringe 1 at the time of inhaling the medicinal liquid, the time of injecting medicinal liquid, the time before the end of medicinal liquid injection, the time of ending the medicinal liquid injection, the time of inhaling the medicinal liquid again, and the time before medicinal liquid injection. It is. In the figure, the hatched portion indicates a portion to which a chemical solution or high-pressure gas is supplied.

(1) After the nozzle holder 3 is rotated and brought into contact with the tip of the cylinder body 4 like the needleless syringe 1 shown in FIG. 1, the lever 81 is pulled as shown in FIG. The lever 81 is released after moving backward (moving to the right in the drawing). Then, the high-pressure gas G is supplied through the joint 11 through the tube 10.

  As shown by the arrows in FIG. 2, the high-pressure gas G passes through the space portion sealed by the packing 82 b and the packing 82 d of the gas supply / discharge chamber 8 a of the gas supply switching unit 8 communicating with the joint 11, and the flow paths 12 and 13. Through the gas chamber 9a of the supply / exhaust switching portion 7 communicating with the space portion and the gas chamber 41a at the rear portion of the pressure receiving piston 52 communicating with the gas supply / discharge chamber 8a via the joint 14, the tube 15, and the joint 16. Each is supplied, and each of these chambers is in a high pressure state.

  As a result, the pressure receiving piston 52 receives a load forward (leftward in the drawing), and the latch ball 61 that is in contact with the through hole 63 a of the ball receiver 63 and the outer peripheral groove 56 a of the piston rod 56 is also penetrated by the piston rod 56. The piston rod 56 is latched and engaged with the cylinder body 4 because it receives the load in the direction of pushing out from the hole 63a but is pressed by the ball press 65 receiving the restoring force of the compression spring 66.

(2) After the container containing the drug solution, for example, the drug solution vial B shown in FIG. 3 is attached to the needleless syringe 1 in the state shown in FIG. 2 via the adapter A, the amount of the drug solution required for the nozzle holder 3 is adjusted. The medical solution Y is inhaled by rotating in the forward direction to a predetermined position. Thereby, the chemical solution in the chemical solution vial B is sucked into the nozzle 2 by a predetermined amount, and the preparation before the chemical solution injection is completed.

(3) The injection is performed by pulling the lever 71 as shown in FIG. When the lever 71 is pulled, the supply / exhaust rod 73 is retracted and the stop valve 75 is also retracted and opened, and the high-pressure gas G in the gas chamber 9a is supplied to the gas chamber 4d through the outer peripheral groove 73a and the flow paths 9b and 9c. Is done. When the gas chamber 4 d becomes high pressure, a high pressure is applied to the rear portion of the ball retainer 65, and the ball retainer 65 moves forward against the compression spring 66.

  Since the pressing force acts on the latch ball 61 from the outer circumferential groove 56a through the piston rod 56, the latch ball 61 is pushed out from the outer circumferential groove 56a, and the latch between the piston rod 56 and the cylinder body 4 is released as shown in FIG. Due to the urging force received by the pressure receiving piston 52 with the high pressure gas, the piston rod 56 advances at a high speed until the stopper 55 comes into contact with the rear portion of the nozzle holder 3, and the chemical Y is injected from the tip of the nozzle 2. When the lever 71 is released, the air supply / exhaust rod 73 moves to the original position by the restoring force of the compression spring 76 as shown in FIG. In this state, the gas chamber 9a, the gas chamber 4d, and the gas chamber 41a are in a high pressure state.

(4) To inhale the same amount of chemical into the nozzle 2 again from the end of the chemical injection, attach the chemical vial B to the tip of the nozzle 2 as shown in FIG. Push to advance. Accordingly, the high pressure gas G is supplied to the gas chamber 4e via the gas supply switching unit 8 and the flow paths 9d and 9e, and at the same time, the high pressure gas G remaining in the gas chamber 41a is supplied to the joint 16, the tube 15, and the joint. 14 enters the gas supply / discharge chamber 8a, and is exhausted to the outside through the gap 9g between the supply direction switching rod 82 and the main body. By these air supply / exhaust operations, the pressure receiving piston 52 moves backward, and the same amount of the chemical liquid Y as the previous time is sucked into the nozzle 2 from the chemical liquid vial B. When changing the amount of inhaled drug solution, the distance between the nozzle holder 3 and the cylinder body 4 is changed.

(5) Next, as shown in FIG. 8, the lever 71 is pulled to complete the preparation for injection. When the lever 71 is pulled, the air supply / exhaust rod 73 moves backward, and the high-pressure gas G remaining in the gas chamber 4d flows into the flow path 9c, the flow path 9b, the outer peripheral groove 73a, and the flow paths 12, 13 shown in FIG. Are sequentially passed to the gas supply switching unit 8 of FIG. 7, and the high-pressure gas in the gas chamber 4d is exhausted as in the case of FIG. By this exhaust, the inside of the gas chamber 4 d is depressurized, and the ball retainer 65 is moved backward by the restoring force of the compression spring 66. Accordingly, the latch ball 61 is fitted into the outer peripheral groove 56a of the piston rod 56, the piston rod 56 is latched by the cylinder body 4, and releasing the lever 71 completes preparation for injection again as in the state shown in FIG.

In addition, the procedure in the case of preparing the nozzle 2 containing the drug solution Y in advance and exchanging with another nozzle 2 for each injection is performed as follows.
In the state of the procedure shown in FIG. 2, the nozzle 2 is not attached, and the nozzle 2 is mounted in a state where the nozzle holder 3 in the state shown in FIG. After the injection, when the state is returned to the state of FIG.

  A high-pressure gas is used as a power source for a needleless syringe that injects and injects a fixed amount of a chemical solution from an injection hole of a nozzle.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view (A) of a needleless syringe according to an embodiment of the present invention, a longitudinal sectional view (B) including an injection / inhalation switching unit, a rear view (C), and a longitudinal sectional view (D) including a gas supply switching unit. It is the longitudinal cross-sectional view (A) of the needleless syringe at the time before chemical | medical solution vial mounting | wearing, and its LM sectional drawing (B). It is a longitudinal cross-sectional view of a needleless syringe at the time of inhaling a chemical solution. It is a longitudinal cross-sectional view of the needleless syringe at the time of the start of chemical liquid injection. It is a longitudinal cross-sectional view of the needleless syringe before the end of the chemical liquid injection. It is a longitudinal cross-sectional view of the needleless syringe at the time of completion | finish of chemical | medical solution injection. It is a longitudinal cross-sectional view of the needleless syringe at the time of inhalation of the chemical solution again. It is a longitudinal cross-sectional view of the needle-less syringe before the time of another chemical injection. It is a longitudinal section showing the example of composition of the conventional needleless syringe.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Needleless syringe 2 Nozzle 2a Injection hole 2b Hollow hole 3 Nozzle holder 3a Hollow hole 3b Male screw 4 Cylinder body 4a Female screw 4b Communication hole 4c Partition wall 4d Gas chamber 4e Gas chamber 41 Cap 41a Gas chamber 42 Screw 5 Chemical solution press 51 Packing 52 Pressure receiving piston 53 Packing 54 Piston 55 Stopper 56 Piston rod 56a Peripheral groove 6 Latch mechanism 6a Male thread 61 Latch ball 62 Screw 63 Ball holder 63A Packing 63B Packing 63a Through hole 64 Packing 64A Packing 65 Ball retainer 66 Spring spring 67 Compression spring 67 7 Supply / exhaust switching portion 71 Lever 72 Packing 73 Supply / exhaust rod 73a Outer peripheral groove 74 Cap 75 Stop valve 76 Compression spring 8 Gas supply switching portion 8a Gas supply / exhaust chamber 81 Lever 82 Supply direction cut Replacement rod 82a Packing 82b Packing 82c Packing 82d Packing 9 Grip 9a Gas chamber 9b Channel 9c Channel 9d Channel 9e Channel 9f Stepped hollow hole 9g Clearance 10 Tube 11 Joint 12 Channel 13 Channel 14 Joint 15 Tube 16 Joint DESCRIPTION OF SYMBOLS 101 Nozzle 101a Injection hole 102 Piston 103 Compression spring 104 Front side grip 105 Piston rod 106 Latch mechanism 107 Injection button 108 Rear side grip 109 Screw part 110 Screw part 111 Nut 112 Flange ring A Adapter B Chemical liquid vial G High pressure gas Y Chemical liquid

Claims (5)

  In a needleless syringe that presses with a piston having a pressure receiving portion to urge a liquid medicine and jets it from a nozzle for injection, a nozzle holder having the nozzle and a communication hole that is connected to the nozzle holder and communicates with the front and rear And a cylinder body in which the second cylinder part accommodates the piston pressure receiving portion, and the first cylinder part accommodates the piston via the partition. A latch mechanism that is disposed in the first cylinder portion and latches the pressurized piston, and includes a pressure receiving portion, and a latch mechanism that releases the latch by the pressurization of the pressure receiving portion, and is disposed in the cylinder body. A first gas flow path for supplying and exhausting high-pressure gas to the first cylinder part, and the first gas flow path from the high-pressure gas source. Supply to the flow channel, non-supply, needleless syringe, characterized in that a first gas switching means for switching the exhaust.   The needleless syringe according to claim 1, further comprising: a second gas flow path for supplying and exhausting high pressure gas between the pressure receiving portion on the partition wall side of the partition wall and the piston in the second cylinder part. And a second gas switching means for switching supply, non-supply, and exhaust of the high-pressure gas from the high-pressure gas source to the second gas flow path and the rear gas chamber of the second cylinder part. Needleless syringe to do.   The latch mechanism is in close contact with an outer peripheral groove formed in the piston, a latch ball that fits into the outer peripheral groove, a latch ball receiver that accommodates the latch ball and is movable in the axial direction, and the first cylinder portion A ball retainer that slides and prevents the latch ball from coming out of the outer peripheral groove, a compression spring that abuts the ball retainer at one end, and a spring stopper that abuts the other end. 3. The needleless syringe according to claim 1 or 2, wherein the piston is latched by latching the piston by movement of a ball presser and releasing the latch of the piston by pressing high pressure gas supplied to the front of the partition wall.   The first gas switching means includes a stepped hollow hole formed in a grip disposed at a lower portion of the cylinder body, a gas flow connecting an intermediate portion of the stepped hollow hole and a gas chamber in front of the partition wall. A rod having an outer circumferential groove formed near the rear portion, a seal packing fitted in front thereof, and a stop valve fixed to the rear end in contact with the stepped hollow hole and shutting off the high-pressure gas flow path; and A cap screwed to the rear end of the stepped hollow hole, a compression spring interposed between the cap and the stop valve, and supply of high pressure gas to the gas chamber by pressing the rod, non-supply, exhaust A switching lever for switching the high pressure gas to the gas chamber in front of the partition wall by pulling the switching lever and pressing the rod when the second gas switching means is in a high pressure gas supply state, By pressurizing the pressure receiving part The ball presser is advanced to start the piston, the switching lever is released and the rod is returned to shut off the supply of the high pressure gas to the gas chamber, and the second gas switching means is in the high pressure gas exhaust state. The needleless syringe according to claim 1, wherein the high pressure gas is exhausted from the gas chamber by pulling the switching lever and pressing the rod.   The second gas switching means includes a hollow hole having three inner circumferential grooves arranged in parallel at intervals in a grip disposed at a lower portion of the cylinder body, an inner circumferential groove on the front side, and a rear side of the partition wall. A gas flow path connecting the gas chambers, a gas supply port for supplying high-pressure gas to the inner circumferential groove in the intermediate portion, a gap for exhausting the high-pressure gas at the rear of the piston pressure-receiving portion via the rear inner circumferential groove, and a pressure-receiving portion A flow path connection port for supplying, non-supplying, and exhausting high pressure gas to the rear gas chamber, and a flow path connection port for supplying and exhausting high pressure gas to the rear gas chamber of the stepped hollow hole are widely used in two places. A diameter stepped portion is provided side by side, a seal packing is fitted to the wide diameter stepped portion, a rod inserted in the hollow hole, and the rod is pressed to shut off the supply of high pressure gas to the gas chamber, A switching lever for releasing the indoor gas, and pulling the switching lever to The gas is discharged, a high pressure gas is supplied to the gas chamber at the rear of the pressure receiving portion, and the rod is pushed in from behind to supply a high pressure gas to the gas chamber at the rear of the partition wall. The needleless syringe according to claim 2, wherein the needleless syringe is evacuated.

Images