JP3089716B2 - Cartridge type syringe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cartridge type syringe. More specifically, the present invention relates to a syringe of a type in which a cartridge pre-filled with a drug solution is inserted into a syringe outer cylinder, that is, a cartridge type syringe.

[0002]

2. Description of the Related Art A cartridge type syringe has a syringe outer cylinder provided with a syringe needle having a cutting edge at both ends at a tip end, a tip end side thereof sealed with a rubber-like elastic sealing member, and a rear end inner surface of a plunger rod. This is a syringe comprising a cartridge pre-filled with a drug solution sealed by a stopper that also serves as a gasket. At the time of use, the cartridge inserted into the syringe outer cylinder is advanced, the sealing member at the front end of the cartridge is pierced with the rear end of the injection needle attached to the tip of the syringe outer cylinder, and the drug solution in the cartridge is injected. Therefore, the engagement strength between the syringe outer cylinder and the cartridge is a large factor that affects the operability. That is, if the engagement strength is appropriate, the cartridge can be advanced smoothly, and stable holding can be achieved. On the other hand, if the engagement is too tight, it will be difficult to advance, and in some cases, it may not be possible to pierce the rear end of the injection needle. This causes problems such as the sealing member coming into contact with the rear end of the injection needle.

As a conventional cartridge type syringe, there is one disclosed in Japanese Utility Model Publication No. 2-12997 (conventional example I). As shown in FIG. 4, this cartridge type syringe has a completely cylindrical inner peripheral surface of the syringe outer cylinder 102, and has a fitting dimension between the inner diameter of the syringe outer cylinder 102 and the outer diameter of the cartridge 101. It is intended to obtain an appropriate engagement strength. The step 126 formed on the inner peripheral surface of the distal end portion of the outer cylinder 102 presses the outer periphery of the distal end portion of the cartridge 101 to press the cartridge 101.
It is a retainer that keeps you from getting out easily.

Another conventional example is a cartridge type syringe (conventional example II) shown in FIG. This cartridge type syringe is formed by forming several long ribs 53 extending in the axial direction on the inner peripheral surface of a syringe outer cylinder 52.
It is intended to realize an engagement strength that allows the cartridge to advance smoothly by bending or deformation of the cartridge.

[0005]

However, none of the conventional examples I and II has been able to stably obtain an appropriate engaging strength. This is because the syringe outer cylinder is generally a synthetic resin molded product, but the inner diameter of the syringe outer cylinder is not constant due to molding distortion, and the cartridge is a glass cylindrical container, but its outer dimensions vary. . For example, since the inner diameter of a syringe barrel made of a propionate resin has a maximum of 5/100 mm and the outer diameter of a glass cartridge has a variation of about ± 1/10 mm, the engagement between the syringe barrel and the cartridge may be tight in some cases. In other cases, it had to be a loose fit.

In view of such circumstances, the present invention absorbs molding distortion in the syringe outer cylinder and variations in the outer dimensions of the cartridge, even if there is, and allows the cartridge to be smoothly advanced in the syringe outer cylinder. Moreover, an object of the present invention is to provide a cartridge-type syringe that can stably hold a cartridge.

[0007]

A cartridge type syringe according to the present invention comprises a cylindrical syringe outer cylinder and a cylindrical cartridge inserted into the syringe outer cylinder, and an inner peripheral surface of the syringe outer cylinder. A thin cylindrical portion is formed concentrically with the inner peripheral surface and cantilevered, and at least three or more convex portions engaging with the outer periphery of the cartridge are formed on the inner periphery of the thin cylindrical portion at equal intervals in the circumferential direction. And the protrusion is the car
The inner circumference of the thin-walled cylinder does not contact the outer circumference of the cartridge.
The thin cylindrical portion has a height sufficient to
Allows circumferential expansion when engaged with cartridge
It is characterized in that it is thick .

[0008]

According to the present invention, since the thin cylindrical portion is provided concentrically inside the syringe barrel, the cartridge is held concentrically within the syringe barrel. The thin cylindrical portion is thin, and only the projection contacts the outer periphery of the cartridge, so that the thin portion adjacent to the projection is easily expanded in the circumferential direction. For this reason, the cartridge and the syringe outer cylinder can elastically contact with each other due to the expansion of the inner diameter of the thin-walled cylindrical portion due to the extension of the portion adjacent to the projection, and the molding distortion of the syringe outer cylinder and the variation in the outer dimensions of the cartridge are reduced. It will be absorbed and the cartridge will be held by the appropriate compression force. Therefore, the advance of the cartridge becomes smooth, and the cartridge can be stably held. Therefore, according to the present invention, the operation of injecting the medicinal solution is facilitated for the nurse, and the yield is improved because the variation in the engagement strength is small in production.

[0009]

Next, embodiments of the present invention will be described. In FIG. 1, reference numeral 1 denotes a cartridge as a drug solution container. This cartridge 1 is usually a cylindrical container made of glass,
A sealing member 2 made of a rubber-like elastic material is fixed to an opening at the front end by an aluminum cap 3, an opening is formed at the rear end, and a plug 4 having a fixing portion for the plunger 12 is formed at the rear end (also serving as a gasket). Are inserted in a liquid-tight manner. The inside of the cartridge 1 is previously filled with a chemical solution m. The configuration of the cartridge 1 is known, and is not different from the conventional example.

Reference numeral 5 denotes a syringe outer cylinder having a closed end and a hub 6 formed with a so-called double-ended needle 7 having cutting edges 7a and 7b at both ends. The outer cutting edge 7a of the double-ended needle 7 is a side that penetrates the human body, and the inner cutting edge 7b is a side that penetrates the sealing member 2 of the cartridge 1. The proximal end of the syringe outer cylinder 5 is open, and the plunger 12 is inserted through this opening and fixed to the plug 4. In this case, the plug 4 functions as a gasket.

The syringe outer cylinder 5 is divided into a distal end portion 5a, an intermediate portion 5b, an engaging portion 5c, and a proximal end portion 5d in order from the distal end direction, and the distal end portion 5a and the intermediate portion 5b are slightly different from the outer shape of the cartridge 1. The engaging portion 5c has a slightly larger inner diameter than the intermediate portion 5b, and the base end portion 5a has a larger inner diameter than the engaging portion 5c. Several ribs 8 are formed on the inner periphery of the distal end portion 5a, and the height of the ribs 8 in the radial direction is such that the ribs 8 can engage with the aluminum cap 3 of the cartridge 1. Therefore, when the cartridge 1 is completely pushed into the syringe outer cylinder 5, the aluminum is easily deformed, so that the ribs 8 can cut into the outer peripheral surface of the aluminum cap 3 to prevent the cartridge 1 from coming off.

A thin cylindrical portion 9 is formed concentrically with the inner peripheral surface of the syringe outer cylinder 5 on the inner peripheral surface of the engaging portion 5c. As shown in detail in FIG. 2, the thin cylindrical portion 9 has a base 9a.
Is of a cantilever type in which the distal end 9a is in a free state, and a convex portion 10 is formed on the inner peripheral surface of the thin cylindrical portion 9. The projection 10 is a projection as shown in FIG.
10a or a thick portion 10b as shown in FIG. Further, the cross-sectional shape of the projection 10a is not limited to a round shape, but may be an arbitrary shape such as a triangle or a trapezoid. When the protrusion 10 contacts the outer periphery of the cartridge 1, if the outer shape of the cartridge 1 is large, the thin portion of the thin cylindrical portion 9 expands in the circumferential direction indicated by the arrow e. In the present embodiment, due to the elongation, the inner diameter of the convex portion 10
Since the diameter expands elastically, the outer dimensions of the cartridge 1
Even if there is a variation, this can be absorbed .

The projections 10 are provided at least three, preferably three to four, at equal intervals in the circumferential direction. If the number is two or less, it is difficult to keep the cartridge 1 concentric. If the number is too large, the engaging strength becomes too large, and it becomes difficult to advance the cartridge. The radial height of the protrusion 10 is
The thickness is determined according to the material and the inner diameter of the thin-walled cylindrical portion 9. When the thin-walled cylindrical portion 9 is a propionate resin described later and has a thickness of 0.3 to 0.5 mm, the thickness is preferably approximately 0.05 to 0.08 mm. The width d of the groove 11 between the outer surface of the thin-walled cylindrical portion 9 and the inner surface of the syringe outer cylinder 5 is a factor that determines the bending allowance of the thin-walled cylindrical portion 9. It is preferable to provide the outer shape of the syringe outer cylinder 5 more than necessary.

It is preferable that the material of the syringe outer cylinder 5 is molded using a propionate resin. Propionate resin is a thermoplastic resin based on cellulose ester, which has excellent transparency, good processability and dimensional stability, and has the same flexibility as polypropylene resin. Since it is excellent in transparency, the state when the cartridge 1 is inserted can be visually confirmed, and the operability as a syringe is also good. Further, since the workability and dimensional stability are good, the production cost can be kept low, and the injection needle can be ultrasonically bonded, so that the double-ended needle 7 is directly fixed to the hub 6 as shown in FIG. be able to. The flexibility equivalent to that of the polypropylene resin gives the thin cylindrical portion 9 an appropriate elasticity, and contributes to the smooth advance in the syringe outer cylinder 5 of the cartridge 1 and the appropriate engagement force.

In addition, any synthetic resin suitable for medical instruments other than the above-mentioned propionate resin can be used without any particular limitation. For example, it can be molded using a polycarbonate resin or a polypropylene resin. Polycarbonate resin has high hardness and is not as good in dimensional stability as propionate resin. However, in terms of hardness alone, if the thickness of the thin cylindrical portion 9 is reduced, the required elasticity can be provided. Although the polypropylene resin cannot ultrasonically bond the needle, it can be used by adopting a type in which the hollow needle and the injection needle are connected by screwing the hubs together without using a double-ended needle.

In this embodiment having the above structure, the protrusion 10
Since the thin cylindrical portion 9 adjacent to the cartridge 1 elastically bends, even if there is a molding distortion of the syringe outer cylinder 5 or a variation in the outer diameter of the cartridge 1, it is absorbed and the syringe outer cylinder 5 is absorbed.
The operation of moving the cartridge 1 forward can be performed smoothly. In addition, since the outer periphery of the cartridge 1 is elastically held, an appropriate engaging force can be obtained. Furthermore, when the cartridge 1 is completely pushed into the syringe outer cylinder 5, the aluminum cap 3 at the tip of the cartridge 1 is pressed by the rib 8 and dented.

[0017]

According to the present invention, the operation of advancing the cartridge to the syringe outer cylinder can be smoothly performed, and the cartridge can be stably held by an appropriate engaging force.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a cartridge type syringe according to one embodiment of the present invention.

FIG. 2 is an enlarged longitudinal sectional view of the thin cylindrical portion shown in FIG.

FIG. 3A is a cross-sectional view of a thin cylindrical portion having a convex portion 10a, and FIG. 3B is a cross-sectional view of a thin cylindrical portion having a convex portion 10b.

FIG. 4 is a longitudinal sectional view of a cartridge type syringe of Conventional Example I.

FIG. 5 is a longitudinal sectional view of a cartridge type syringe of Conventional Example II.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cartridge 3 Aluminum cap 5 Syringe cylinder 8 Rib 9 Thin cylindrical part 10 Convex part

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) A61M 5/24 C08L 1/08

Claims (3)

(57) [Claims] 1. A syringe comprising a cylindrical syringe outer cylinder and a cylindrical cartridge inserted into the syringe outer cylinder. The inner peripheral surface of the syringe outer cylinder is concentric with the inner peripheral surface and cantilevered. thin cylindrical portion is formed, further mosquitoes on the inner periphery of the thin cylindrical portion - the convex portions periphery engaging the cartridge equiangularly forms at least three or more places, the convex portion is the car
The inner circumference of the thin-walled cylinder does not contact the outer circumference of the cartridge.
The thin cylindrical portion has a height sufficient to
Allows circumferential expansion when engaged with cartridge
A cartridge-type syringe characterized in that it has a small thickness . 2. A cartridge type syringe according to claim 1, wherein said syringe outer cylinder is formed of a propionate resin. 3. The cartridge type syringe according to claim 1, wherein a rib is formed on an inner periphery of a distal end portion of the syringe outer cylinder so as to engage with an aluminum cap at a distal end portion of the cartridge.