JP2001204819A - Needleless injector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a needleless injector in which a piston rod is not erroneously started even when a release switch for starting it for injecting a liquid medicine is touched after the liquid medicine is sucked and before it is injected. SOLUTION: An L-shaped recessed part 8a at a rear part of a rear side cylindrical part 8, and a protruded part at a release switch 7 are provided, and torque of the rear side cylindrical part 8 in retracting is transmitted through a ball 11 to the release switch 7, so the protruded part 7a is moved to an advance prohibiting zone in the recessed part 8a. The release switch 7 is thus automatically prevented from being pushing in, and erroneous start of a piston rod 5 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a needleless syringe for performing subcutaneous injection by jetting a predetermined amount of a chemical solution inhaled from an injection hole of a nozzle.

[0002]

2. Description of the Related Art A needleless syringe is a syringe that injects a drug solution into a patient's subcutaneous skin by injecting a predetermined amount of a drug solution from a nozzle orifice of a nozzle at the tip and jetting the drug solution again from the nozzle orifice. In other words, injection using a needleless syringe does not use a needle at the time of subcutaneous injection, and thus has the advantages of not causing pain, leaving no injection mark, and having no injection mistakes. It is also used for injection.

[0003] Such a needleless syringe generally has a configuration as shown in FIG. 9. That is, the needleless syringe is a piston driving rod (hereinafter abbreviated as a piston rod) 2 that connects a front cylindrical portion 23 in which a nozzle 21 having an injection hole 21a is incorporated and a piston 24.
A latch mechanism 22 for latching (fixing) or releasing the lock 5 and a rear cylindrical portion 28 incorporating a release switch 27 are screwed together with a screw portion 29. A flange ring 20 is integrally fixed to a front portion of the piston rod 25, and a compression spring 26 is attached between the flange ring 20 and a rear wall of the rear cylindrical portion 28 through the piston rod 25.

[0004] From the state of FIG.
8, the latch mechanism 22 latches the piston rod 25 and compresses the compression spring 26,
A forward force is applied to the piston rod 25 by the compression force. In this state, the nozzle 21 of the needleless syringe is pressed against the suction port of the drug solution vial (not shown) and the rear cylindrical portion 2 is pressed.
When the nozzle 8 and the piston 24 are retracted by rotating
The drug solution is sucked into the space between them. When the release switch 27 is pressed while the nozzle 21 is pressed against the injection site after inhaling the predetermined amount of the drug solution, the latch of the latch mechanism 22 is released, the piston rod 25 becomes free and moves forward at a high speed, and the drug solution is The injection hole 21 is pressurized by the piston 24
It is injected subcutaneously from a.

[0005]

The conventional needleless syringe is constructed as described above. However, in such a needleless syringe, if a strong force is required to press the release switch 27, the syringe may be swung at the time of injection. Nozzle 21
Since it is impossible to accurately inject the drug solution due to movement from the injection site or the like, the pushing force cannot be increased too much. As a result, the piston rod 25 may be erroneously started by inadvertently touching the release switch 27 before injecting after inhaling the drug solution. For this reason, for example, there is also a needleless syringe equipped with a stopper that can be prevented from being pushed by manually rotating the release switch 27.

However, even if such a needleless syringe is used, after the piston rod 25 is latched on the rear cylindrical portion 28, the stopper of the release switch 27 is manually rotated to prevent the piston rod 25 from starting. The piston rod 2
There is a problem that 5 is started. The present invention has been made in view of such circumstances, and has as its object to provide a needleless syringe that can automatically prevent erroneous starting of the piston rod 25.

[0007]

In order to achieve the above-mentioned object, a needleless syringe according to the present invention provides a high-speed piston which is biased in advance in a latched state in a chemical solution sucked from an injection hole of a nozzle. In a needleless syringe that pushes in and ejects a drug solution, a ball receiver provided in the rear cylindrical portion, a plurality of balls in the ball receiver, and a piston driving rod through which each part of the ball enters and exits are provided. A latch groove and a latch mechanism including a release switch for controlling the projection of each ball from the latch groove are provided, and a convex portion is provided on the release switch, and a concave portion in which the convex portion is inserted into a rear cylindrical portion. The pressing operation of the release switch can be automatically prevented depending on the shape of the convex portion and the concave portion and the rotation direction of the rear cylindrical portion. The needleless syringe of the present invention is configured as described above, and can prevent erroneous starting of the piston driving rod caused by erroneously touching or pressing the release switch.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The needleless syringe of the present invention will be described in detail below with reference to embodiments. 1 (a) and 1 (b) are a top view and a longitudinal sectional view of the needleless syringe of the present invention after injection. As shown in FIG. 1, the needleless syringe of the present invention includes a nozzle 1 having an injection hole 1a for inhaling a chemical solution when the piston 4 with the seal member 4a connected to the distal end retreats and ejecting the chemical solution when moving forward. A front cylindrical portion 3 which is fixed by screwing or the like and has a chemical liquid amount display window 2 opened in the outer peripheral portion;
A small hole 17 for moving a plurality of balls 11 in a direction perpendicular to the piston rod 5 is provided for latching (fixing) the piston rod 5 which is movable in the axial direction by connecting the piston 4 inserted therein. The ball receiver 14 and the rear cylindrical portion 8 into which the release switch 7 provided with the contact surface 18 for controlling the protrusion of the ball 11 is inserted against the compression spring 16 by screwing the screw portion 9 together. It is configured.

FIGS. 2A and 2B are a top view and a side view of an inner cylindrical portion of the rear cylindrical portion 8 in the above configuration, and FIGS. 3A and 3B are a top view and a side view of the release switch 7, respectively.
FIGS. 4A and 4B are a top view and a side view showing a state where the release switch 7 is inserted into the rear cylindrical portion 8 in FIG. A concave portion 8a and a concave portion 8b as shown in FIG. 2 which are features of the present invention are provided in an inner cylindrical portion of the rear cylindrical portion 8, and a convex portion 7a and a convex portion 7 shown in FIG.
b is provided. By pushing the release switch 7 into the rear cylindrical portion 8, the convex portions 7a and 7b are disposed in the concave portions 8a and 8b, respectively, as shown in FIG. 4, and the rotation of the release switch 7 is prevented. You.

[0010] A flange ring 13 is fixed to the distal end of the piston rod 5.
3 and a piston rod 5 between the inner rear wall of the rear cylindrical portion 8.
, A compression spring 15 is interposed. A number (for example, 0 to 5) for indicating the amount of the chemical is displayed on the chemical amount display window 2 in accordance with the rotation pitch on the cylindrical surface of the rear cylindrical portion 8 that has entered the front cylindrical portion 3. The number displayed in the chemical liquid amount display window 2 changes according to the movement of the rear cylindrical portion 8.

When the rear cylindrical portion 8 of the needleless syringe is rotated clockwise (as viewed from the release switch 7 side), the rear cylindrical portion 8 moves forward together with the ball 11. When the ball 11 reaches the latch groove 12, a part of the ball 11 sinks into the latch groove 12, and at the same time, the contact surface 18 is moved onto the ball 11 by the urging force of the compression spring 16. This allows
The piston rod 5 is latched by the rear cylindrical portion 8 via the ball 11 in the latch groove 12, and the release switch 7 is moved backward until the convex portion 7a is retracted and hits the rear edge of the concave portion 8a of the rear cylindrical portion 8. The needleless syringe that has protruded is in the state shown in FIG. Then, the convex portions 7a and 7b of the release switch 7 move behind the advanceable zone as shown in FIG. 6 in the concave portions 8a and 8b of the rear cylindrical portion 8, and the needleless syringe is used for inhaling the medicinal solution. It becomes possible state.

Next, when the nozzle 1 of the needleless syringe shown in FIG. 6 is pressed against the suction port of the drug solution vial (not shown) and the rear cylindrical portion 8 is rotated counterclockwise, the piston rod 5 keeps the forward force. Then, the nozzle 1 moves rearward while sucking the chemical from the injection hole 1a. The ball 11 is a piston rod 5
And the contact surface 18 of the release switch 7
When the rear cylindrical portion 8 is rotated in the direction of the arrow in FIG. 7 (counterclockwise as viewed from the release switch 7 side), the ball 11 is also rotated. When this rotation is transmitted to the release switch 7, the release switch 7 is also rotated. Rotate in the direction of arrow 7 (counterclockwise). Thereby, the convex portion 7b and the convex portion 8b of the release switch 7 are moved to the forward-prohibition zone on the left side of the concave portion 8a and the concave portion 8b of the rear cylindrical portion 8 as shown in FIG.

In the state shown in FIG. 8, the convex portion 7a and the convex portion 7b of the release switch 7 are blocked from moving forward by the concave portion 8a and the concave portion 8b, respectively. You. When performing the injection, the protrusion 7a is manually rotated clockwise to move from the push-in prohibited zone to the push-in zone, and then the release switch 7 is pushed in. As described above, the rear switch 8 is rotated counterclockwise in the locked state, and the release switch 7 is automatically pushed into the prohibition state at the stage when the liquid medicine is inhaled. Thereby, it is possible to prevent the chemical liquid from being erroneously fired between the time when the predetermined amount of the chemical liquid is inhaled and the time when the injection is performed.
In addition, the convex portion 7b reinforces the strength of the convex portion 7a, and can be omitted by providing the convex portion 7a with sufficient strength.

As shown in the above embodiment, the present needleless syringe has a release switch provided with a projection and a recess having a zone in which the projection of the projection is inhibited by rotating the rear cylindrical portion. The feature is that the release switch is prohibited from being pushed by mistake between the inhalation of the drug solution and the injection, and the piston rod is not accidentally started, and the shape and size of the protrusions and dents are implemented in this implementation It is not limited by the example.

[0015]

The needleless syringe of the present invention is constructed as described above, and when the piston rod is rotated and retracted for inhaling the chemical, the projection of the release switch prevents the recess of the rear cylinder from advancing. By providing a mechanism for automatically moving the piston rod, it is possible to prevent the piston rod from erroneously starting even if the release switch is inadvertently contacted or pushed during the period from the start of the chemical solution inhalation operation to the injection.

[Brief description of the drawings]

FIG. 1 is a top view (a) and a longitudinal sectional view (b) of a needleless syringe according to an embodiment of the present invention.

FIG. 2 is a top view (a) and a side view (b) of an inner portion of a rear cylindrical portion according to the present invention.

FIG. 3 is a top view of a release switch according to the present invention (a).
It is a side view (b).

FIG. 4 is a top view (a) and a side view (b) in a state where the rear cylindrical portion and the release switch are coupled to each other.

FIG. 5 is a top view (a) and a longitudinal sectional view (b) of a needleless syringe according to an embodiment of the present invention.

FIGS. 6A and 6B are a top view and a side view in a state where the rear cylindrical portion and the release switch are combined.

FIG. 7 is a sectional view of the rear cylindrical portion (FIG. 5) taken along line AA.

FIGS. 8A and 8B are a top view and a side view in a state where the rear cylindrical portion and the release switch are combined.

FIG. 9 is a schematic sectional view of a conventional needleless syringe.

[Explanation of symbols]

1, 21 ... Nozzle 8, 28 ... Rear cylindrical part 1a, 21a ... Injection hole 9, 29 ... Screw part 2 ... Chemical amount display window 11 ... Ball 3, 23. ..Front cylindrical portion 12 ... Latch groove 4,24 ... Piston 13,20 ...
Flange ring 4a Seal member 14 Ball receiver 5, 25 Piston rod 15, 16, 26
··· Compression springs 7, 27 ··· Release switch 17 ··· Small holes 7a, 7b ··· Convex part 18 ··· Contact surface 8a, 8b ··· Concave part 22 ··· Latch mechanism

Continued on the front page (72) Inventor Haruhide Udagawa 1 Shiwazu Seisakusho Co., Ltd., Nishi-no-Kyowa-cho, Nakagyo-ku, Kyoto (72) Masahiko Yoneya 1-111-13, Shimizu, Asahi-ku, Osaka-shi Nippon Pharmaceutical Co., Ltd. Terms (reference) 4C066 AA09 BB01 DD08 DD13 EE06 FF02 HH26

Claims (1)

[Claims] A needle provided in a rear cylindrical portion of a needleless injector for injecting a liquid medicine sucked from an injection hole of a nozzle at a high speed by pushing a piston, which is preliminarily urged forward in a latched state, and injecting the liquid medicine; A ball holder, a plurality of balls in the ball receiver, a latch groove provided in a piston driving rod through which each part of the ball enters and exits, and a release switch for controlling the projection of each ball from the latch groove. In addition to providing a latch mechanism, a protrusion is provided on the release switch, and a recess is provided in the rear cylindrical portion where the protrusion is inserted, and the release is performed according to the shape of the protrusion and the recess and the rotation direction of the rear cylindrical portion. A needleless syringe characterized in that a switch pressing operation can be automatically prevented.