JPH07513A - Injection cylinder - Google Patents

Abstract

PURPOSE:To lower the force to actuate an inside cylinder by consisting the inside cylinder of a front end made of an elastic material having a function to hermetically seal the inside by coming into tight contact with the inside wall of an outside cylinder and a plunger pressing this front end, projecting the medicinal liquid contact surface at the front end of the inside cylinder and forming the plunger contact surface of the inside cylinder as a recessed part. CONSTITUTION:The surface A having the projecting shape in contact with the medicinal liquid, the surface B having the recessed shape in contact with the front end D of the plunger and the surface C in tight contact with the inside wall of the injection cylinder are formed on the inside cylinder to be inserted into the outside cylinder. The sliding characteristic of the inside cylinder is improved if the part (a) in contact with the plunger of the surface B is set on the side of the surface C in tight contact with the inside wall of the outside cylinder where this surface comes into contact with the medicinal liquid, i.e., the side nearer the surface A than (b). Polypropylene, etc., are used for the plunger. The front end of the inside cylinder is composed of the elastic material, such as butyl rubber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drug solution filling syringe having excellent usability. More specifically, the present invention relates to an injection cylinder having excellent airtightness during storage of contents and excellent slidability of an inner cylinder during use.

[0002]

2. Description of the Related Art A product sold by enclosing a liquid medicine in a syringe is sterilized while the liquid medicine is filled in the syringe, and therefore liquid leakage often occurs due to pressure change in the syringe after and during sterilization. . In addition, when it is distributed as a product, it may leak from the gap between the inner cylinder and the outer cylinder, which serve as the lid. In order to prevent this liquid leakage, many of the currently used syringe barrels have been devised in the inner barrel of the syringe barrel, but the most common type is a rubber typified by butyl rubber at the tip of the inner barrel. Some of them are used and the shape is elaborate. For example, the actual Kaisho 60-4
In No. 9846, the inner cylinder is formed of a convex spherical surface or a concave spherical surface that is substantially concentric with the injection hole of the injection needle, thereby increasing the contact pressure of each part and preventing the injection liquid from leaking out.

However, there is a drawback in that as the liquid leakage is prevented and the sealing performance is improved, a large force is required to move the inner cylinder during use. If a blood vessel contrast agent or the like is enclosed as a content, it is difficult to press with human force, in addition to the condition that the viscosity is high and the amount is large. In such a case, it is the current situation that the piston is pressed by a device such as a power injector, but these devices are expensive, and it is difficult to adjust the injection amount. Therefore, further improvement is required. ing.

[0004]

In view of the above situation, the present inventors have made an injection in which the inner cylinder can move smoothly with a slight force during use without liquid leakage during sterilization or storage. The research of the cylinder started.

In order to achieve the above object, the present inventors consider that it is useful to change the frictional force between the inner wall of the injection barrel and the inner barrel at the time of storage and during use. As a result of repeated studies on the above, it was found that the syringe having the following structure achieves the intended purpose, and the present invention was completed.

[0006]

That is, according to the present invention, in an injection cylinder composed of an outer cylinder and an inner cylinder, the inner cylinder has a tip made of an elastic material that functions to closely adhere to the inner wall of the outer cylinder and seal the inside. The injection cylinder is characterized by comprising a plunger for pressing the same, the contact surface of the inner cylinder with the liquid medicine is convex, and the contact surface with the plunger is concave.

According to the present invention, the syringe filled with the drug solution does not leak during sterilization or storage, and the drug solution can be injected with a slight force at the time of use. It is an object of the invention to provide.

In the elastic material used at the tip of the inner cylinder, the elastic material may be rubber material such as butyl rubber or silicon rubber, but if it is a material showing similar properties, the elastic material is used as the tip of the inner cylinder of the present invention. Can be used.

FIG. 1 shows a schematic view of a longitudinal sectional view of the tip of the inner cylinder. The surface A is the surface in contact with the chemical solution, and the surface B is the surface in contact with the plunger. The surface C is a surface that comes into close contact with the inner wall of the outer cylinder of the injection cylinder. The portion a is a portion that comes into contact with the plunger. The portion a is forward of the side of the surface where the inner wall of the injection cylinder outer cylinder and the tip of the inner cylinder are in close contact with each other, that is, closer to the surface A than b. On the other hand, more preferable results can be obtained in improving the slidability of the inner cylinder of the injection cylinder. As the material of the plunger for pressing the tip of the inner cylinder, any material that is normally used can be used, and for example, polypropylene or other polymers can be used.

FIG. 2 shows a schematic diagram of the plunger. D
Is the end that contacts the concave surface of the syringe barrel inner barrel. The angle of D is
An acute angle is preferable to the angle of the B surface shown in FIG. The method of mounting the plunger and the syringe barrel inner cylinder is not particularly limited. Since it is possible to inject stably without using a special mounting method, it is sufficient to simply press the plunger against the tip of the inner cylinder when pressing the inner cylinder, but between the inner cylinder of the injection cylinder and the plunger. A mounting mechanism can be provided in the.

Further, if the portion that presses the plunger is the central portion of the tip of the inner cylinder, the tip of the inner cylinder undergoes a preferable deformation, so that the frictional force between the tip of the inner cylinder and the inner wall of the outer cylinder is efficiently reduced, Good results can be obtained.

The syringe according to the present invention can be used for any purpose when a normal syringe is used. However, in view of the features of the present invention, it is put on the market in a pre-filled syringe or the like in which a drug is pre-filled. It can be particularly useful for certain types of syringes.

Further, the syringe according to the present invention can be applied to any size, and this is also one of the features of the present invention. In particular, a syringe for an angiographic agent or the like for which a high dose must be used. When used as such, the usefulness of the syringe according to the present invention is exerted.

The present invention will be described in detail below with reference to the drawings, but the present invention is not limited thereto. FIG. 3 shows an example of the injection cylinder according to the present invention. In FIG. 3, the component 1 is
It is a part that constitutes the tip of the inner cylinder of the injection cylinder, and is a component made of an elastic material. Part 2 is the plunger and part 3
Is the outer cylinder of the syringe barrel. The component 1 is attached to the outer cylinder of the injection cylinder so that the convex surface is in contact with the drug solution, and seals the drug solution. The component 2 is applied to the concave surface of the component 1 which is opposite to the convex surface in contact with the chemical liquid and pressed to inject the contents into the chemical liquid. In this case, it is possible to obtain a preferable result when F in FIG. 3 is closer to the front than G, that is, to the surface in contact with the content, as shown in FIG.
Furthermore, when the component 2 is mounted on the component 1, it is preferable that the angle of the convex surface of the component 2 is more acute than the angle of the concave surface of the component 1.

[0015]

In the present invention, the reason why the slidability of the inner cylinder is enhanced is considered as follows. In a normal state, as shown in FIG. 4A, the tip of the inner cylinder is in close contact with the inner wall of the outer cylinder. When pressing the tip of the inner cylinder with the plunger during use,
As shown in FIG. 4 (2), the tip of the inner cylinder is slightly deformed, and the pressure due to the contact between the tip of the inner cylinder and the inner wall of the outer cylinder is reduced. Therefore, the frictional force between them becomes small, and it becomes possible to push the tip of the inner cylinder with a slight force.

[0016]

Next, in order to facilitate understanding of the present invention,
An experimental example is shown. Experimental example Measurement of pressure required for inner cylinder sliding

I) Experimental method The pressure of the syringe barrel according to the present invention and the conventional syringe barrel during sliding of the inner barrel was measured. The pressure applied to the inner cylinder when the inner cylinder was pressed so that the inner cylinder sliding speed was 500 mm / min was shown.

Ii) Experimental Results The changes in pressure are shown in FIGS. 5 and 6. The vertical axis represents the pressure (kg / cm ² ) applied to the inner cylinder, and the horizontal axis represents the time (second). As can be seen in this figure, the flow chart for a conventional syringe barrel is fairly sharp. When moving the inner cylinder,
An extremely strong pressure is instantaneously required, and the inner cylinder cannot continue to slide unless gradually increasing pressure is applied.

However, as is clear from the figure, the syringe according to the present invention requires less momentary pressure when starting to slide, and moreover, the pressure required after sliding almost changes. You can see that there is no.

From the above experimental results, it is clear that the injection cylinder according to the present invention requires very little pressure when the inner cylinder slides, as compared with the conventional injection cylinder. From this, it became clear that the syringe according to the present invention has good operability during use.

[Brief description of drawings]

FIG. 1 shows the tip of an inner cylinder of an injection cylinder according to the present invention.

FIG. 2 shows a syringe barrel plunger according to the present invention.

FIG. 3 shows an example of a vertical sectional view of an injection cylinder according to the present invention.

FIG. 4 shows a mechanism for improving the slidability of the inner cylinder of the injection cylinder according to the present invention.

FIG. 5 shows a flowchart of a pressure change applied to the inner cylinder of the conventional injection cylinder when the inner cylinder slides.

FIG. 6 shows a flowchart of a pressure change applied to the inner cylinder of the injection cylinder according to the present invention when the inner cylinder slides.

Claims (4)

[Claims] 1. An injection cylinder comprising an outer cylinder and an inner cylinder,
The inner cylinder is composed of a tip made of an elastic material that closely adheres to the inner wall of the outer cylinder and seals the inside, and a plunger that presses the tip, and the tip of the inner cylinder and the contact surface of the chemical solution are convex. A syringe having a concave contact surface with a jar. 2. The concave portion of the inner cylinder tip made of an elastic material, the deepest part of the recess is located in front of the side of the surface where the inner wall of the injection cylinder outer tube and the tip of the inner cylinder are in close contact with the drug solution. The syringe according to claim 1, which is characterized in that. 3. A plunger is used to press the central portion of the concave surface at the tip of the inner cylinder made of an elastic material.
The syringe described. 4. The syringe barrel according to claim 1, wherein the angle of the tip of the plunger is more acute than the angle of forming a concave recess on the tip of the inner barrel.