JP4392083B2 - Needleless syringe - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a needleless syringe that performs a subcutaneous injection by jetting a fixed amount of a chemical solution sucked from an injection hole of a nozzle.
[0002]
[Prior art]
A needleless syringe is a syringe that injects a chemical solution into a patient's skin by injecting a certain amount of the chemical solution from an injection hole of a nozzle at the tip thereof and then jetting the chemical solution again through the injection hole. In other words, injection with a needleless syringe does not use an injection needle at the time of subcutaneous injection, so there are advantages such as no pain, no injection marks, no injection mistakes, etc. It is also used when injecting.
[0003]
Such a needleless syringe generally has a structure as shown in FIG. In other words, the needleless syringe is provided with the front cylindrical portion 3 in which the nozzle 1 having the injection hole 1a is incorporated, the latch mechanism 23 for latching (fixing) or releasing the rod 5 to which the piston 4 is connected, and the latch release button 7. The side cylindrical portion 8 is configured to be screwed with a screw portion 9.
A flange ring 13 is integrally fixed in front of the rod 5, and a compression spring 15 is disposed between the flange ring 13 and the rear inner wall of the rear cylindrical portion 8 through the rod 5.
[0004]
When the rear cylindrical portion 8 of the needleless syringe is rotated and advanced, the tip of the piston 4 advances to the inner wall of the nozzle 1, and the latch mechanism 23 latches the rod 5 and compresses the compression spring 15. The force of the rod 5 is biased forward by the force.
In this state, when the nozzle 1 is brought into contact with a chemical vial (not shown) storing the chemical and the rear cylindrical portion 8 is rotated and retracted, the chemical is sucked into the space formed between the nozzle 1 and the piston 4. . When the latch release button 7 is pressed while the nozzle 1 is pressed against the injection site, the latch of the latch mechanism 23 is released, the rod 5 becomes free and moves forward at high speed, and the drug solution is pressurized by the piston 4. It is injected from the injection hole 1a and injected subcutaneously.
[0005]
A state where the latch mechanism 23 latches the rod 5 is shown in FIG. As shown in FIG. 5, the balls 11 in the plurality of small holes 17 provided in the fixing ring 14 fall into the grooves 12 provided in the rod 5, and the opposite surface thereof is the flat portion 7 a of the latch release button 7. The rod 5 is held by the rear cylindrical portion 8.
Further, a compression spring 16 is interposed between the ball receiver 19 and the latch release button 7, and the latch release button 7 is rearward until it hits a holding block 20 fixed to the rear cylindrical portion 8 by a screw 21 due to the repulsive force. Extruded fully. In this state, the rod 5 moves back and forth integrally with the rear cylindrical portion 8.
[0006]
To release the latch state, the latch release button 7 is pushed forward. Then, the flat surface portion 7a slides on the ball 11 and moves forward, and the ball 11 jumps out of the groove 12, and at the same time, the rod 5 advances at a high speed by receiving a motion force corresponding to the compression force from the compression spring 15. Then, as shown in FIG. 6, after the rod 5 has advanced, the ball receiver 19 is separated from the recess 24 of the rod 5 and enters the fixing ring 14, and the state where the ball 11 is prevented from coming out of the small hole 17 is maintained.
[0007]
[Problems to be solved by the invention]
Although the conventional needleless syringe is configured as described above, the flat surface portion 7a and the ball 11 are normally in a contact relationship as shown in FIG. 7 (a), and the ball 11 is in the arrow direction A of the latch release button 7. , A frictional force is generated in the arrow direction B due to friction with the small hole 17 in contact with the ball 11 and the groove 12 of the rod (FIG. 5). Thus, in order to move the flat surface portion 7a forward from the ball 11 and release the latch, the latch release button 7 is applied with a force that is greater than the force that compresses the compression spring 16 and the frictional force generated on the ball 11. Must be added. This force may cause unnecessary movement of the needleless syringe at the injection site during injection and cause an injection failure.
[0008]
Further, as shown in FIG. 7B, when the ball mark 7b is made on the flat surface portion 7a due to long-term use, the slip of the ball 11 with respect to the flat surface portion 7a is deteriorated, and the flat surface portion 7a is moved forward of the ball 11. Need more power. Thus, there is a problem that the greater the force with which the latch release button 7 is pressed, the greater the probability of an injection failure.
[0009]
This invention is made | formed in view of such a situation, Comprising: It aims at providing the needleless syringe which does not cause injection failure by providing the latch release means which can be operated by light force.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a needleless syringe according to claim 1 is provided for latching a piston rod in a needleless syringe in which a piston rod is advanced at a high speed to inject an injection solution in a nozzle and injected subcutaneously. And a ball hole provided in the cylindrical portion on the rear side of the syringe for positioning the ball, and a ball contact provided with an inclined surface inclined toward the piston rod in order to prevent the ball from protruding from the ball hole. And a latch mechanism composed of a piston rod provided with a groove for fitting a part of the ball protruding from the opposite side of the ball hole, and having a latch release button incorporating the ball contact, the latch release button Thus, the latch mechanism is operated by moving the ball contact .
[0011]
According to a second aspect of the present invention, there is provided the needleless syringe according to the first aspect, wherein the ball contact is made of a material harder than the ball that latches the piston rod .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the needleless syringe of the present invention will be described in detail by way of examples. FIG. 1 is a side sectional view of the needleless syringe of the present invention. In the following drawings, parts having the same functions as those of the conventional example are denoted by the same symbols.
As shown in FIG. 1, the structure of the needleless syringe of the present invention is as follows. The nozzle 1 sucks the chemical solution when the piston 4 moves backward, and injects the chemical solution when the piston 4 moves forward. A ball 11, a groove 12, a small hole 17, and a latch 11 for latching (adhering) a rod 5 that moves forward and backward by connecting a front cylindrical portion 3 that opens a display window 2 and a piston 4 inserted in the nozzle 1. A latch mechanism 23 including a ball receiver 19 and a rear cylindrical portion 8 provided with a latch release button 7 for releasing the latched state are screwed together by a screw portion 9.
[0013]
The rod 5 is formed with a groove 10 for connecting the piston 4 from the front end side, and a groove 12 into which the ball 11 is fitted by rotating the rear cylindrical portion 8 forward, and the flange ring 13 is integrally formed. It is fixed.
A compression spring 15 is interposed through the rod 5 between the flange 6 disposed in contact with the flange ring 13 and the fixed ring 14 fixed to the rear cylindrical portion 8.
A number for indicating the amount of the chemical in the chemical amount display window 2 is displayed on the cylindrical surface of the rear cylindrical portion 8 that has entered the front cylindrical portion 3 in accordance with the rotation pitch. The number displayed on the chemical amount display window 2 changes according to the movement of the part 8.
[0014]
2 is a partial cross-sectional view of the needleless syringe for explaining the latch mechanism 23, and FIG. 3 is a contact view of the latch release button 7 and the ball.
In FIG. 2, the balls 11 in the plurality of small holes 17 provided in the fixing ring 14 fall into the grooves 12 provided in the rod 5, and the opposite surface of the balls 11 per 18 balls incorporated in the latch release button 7. The rod 5 is pressed by the contact surface 18 a and is latched to the rear cylindrical portion 8.
[0015]
Further, a compression spring 16 is interposed between the ball receiver 19 and the latch release button 7, and the latch release button 7 is rearward until it hits a holding block 20 fixed to the rear cylindrical portion 8 by a screw 21 due to the repulsive force. Extruded fully. In this state, the rod 5 moves back and forth integrally with the rear cylindrical portion 8.
[0016]
The contact surface 18a of the 18 per ball is given a certain inclination with the front side facing downward relative to the horizontal plane. When the latch release button 7 is pressed from the above state, the ball contact 18 advances to a position as indicated by a dotted line in FIG. In this case, the contact between the contact surface 18a and the ball 11 is weakened as it moves forward, so that the force to push the latch release button 7 can be weakened, so that the latch release as shown in FIG. A ball mark that causes an increase in the operating force of the button 7 is not attached.
[0017]
In addition, the needleless syringe according to another embodiment of the present invention is a needleless syringe configured as shown in FIG. 2, and the material of the ball itself 18 is compared with that of the ball 11 regardless of whether the contact surface 18 a is inclined. Using hard and hard materials. According to this embodiment, even if the contact surface 18 a is not inclined, the frictional force is reduced due to the difference in hardness between the ball contact 18 and the ball 11 and the wear only occurs along the spherical surface of the ball 11. Thus, the ball per 18 does not have a ball mark, and the good slip of the 18 per ball on the ball 11 is maintained, and the operation of the latch release button 7 can always be performed with a light force.
Thus, in this embodiment, the operability of the latch release button 7 can be improved by making the material of the ball 18 harder than the ball 11 without inclining the contact surface 18a. By providing a slight inclination of the surface 18a, sharpness can be added to the switching operation when the latch is released.
[0018]
In addition, you may manufacture the said 18 per ball | bowl and the latch release button 7 as an integral object, for example with a mold.
As shown in the above embodiment, the needleless syringe is characterized in that a contact surface per ball for taking in and out the ball in the fixing ring is inclined or a material harder than the ball is used per ball. The shape of the structure other than these is not limited by this embodiment.
[0019]
【The invention's effect】
The present needleless syringe of the present invention is configured as described above, and the frictional force between the ball and the contact surface is reduced by inclining the contact surface in contact with the ball with respect to the axial direction. The operating force can be reduced. Also, by making the material per ball harder than the ball, the ball mark on the contact surface can be eliminated, and the sliding between the ball and the contact surface can be improved. In both cases, the operation of the latch release button becomes lighter and there is no injection failure. .
[Brief description of the drawings]
FIG. 1 is a side sectional view of a needleless syringe according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a latch mechanism portion of the present invention.
FIG. 3 is a contact diagram of a ball contact and a ball according to the present invention.
FIG. 4 is a schematic cross-sectional view of a conventional needleless syringe.
FIG. 5 is a cross-sectional view of a latch mechanism portion in a latched state of a conventional needleless syringe.
FIG. 6 is a cross-sectional view of a latch mechanism portion in a latch release state of a conventional needleless syringe.
7A and 7B are a normal contact diagram (a) of a conventional ball contact member and a ball and a contact diagram (b) having a ball mark.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Nozzle 11 ... Ball 1a ... Injection hole 13 ... Flange ring 2 ... Chemical liquid amount display window 14 ... Fixing ring 3 ... Front side cylindrical part 15, 16 ... Compression Spring 4 ... Piston 17 ... Small hole 5 ... Rod 18 ... 6 per ball 6 ... Flange 18a ... Contact surface 7 ... Latch release button 19 ... Ball receiver 7a ... -Flat part pressing block 20 ... pressing block 7b ... ball mark 21 ... screw 8 ... rear cylindrical part 23 ... latch mechanism 9 ... screw part 24 ... dent 10, 12 ···groove

Claims (2)

In a needleless syringe that advances the piston rod at high speed and injects the injection solution in the nozzle and injects it subcutaneously, a ball for latching the piston rod and a cylindrical portion on the rear side of the syringe for positioning the ball And a part of the ball coming out from the opposite side of the ball hole and a ball contact provided with an inclined surface inclined toward the piston rod in order to suppress the ball jumping out from the ball hole A latch mechanism comprising a piston rod provided with a groove; and a latch release button incorporating the ball contact, wherein the ball contact is moved by the latch release button to operate the latch mechanism. Needleless syringe.   2. The needleless syringe according to claim 1, wherein the ball is made of a material harder than a ball for latching the piston rod.

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