JP6772517B2 - Plunger and syringe and prefilled syringe using it - Google Patents

Description

The present invention relates to a plunger provided with a mechanism for preventing the plunger rod from falling off from the gasket, and a syringe and a prefilled syringe using the same.

A normal syringe is obtained by press-fitting a plunger rod (an assembly of a bottom rod and a coupler) into a gasket, assembling it as a set in advance, and then inserting the gasket into the barrel. On the other hand, a syringe filled with a chemical solution, that is, a prefilled syringe is usually obtained by filling a barrel with a chemical solution, plugging the gasket, and then connecting the plunger rod to the gasket. That is, a method of connecting a plunger rod to a syringe with a gasket stopper as a post-process is adopted as a method of obtaining a prefilled syringe. This method is adopted because if the gasket is provided with the plunger rod in advance, the plugging process for sealing the chemical solution becomes difficult.

As a method of connecting the gasket of the prefilled syringe and the plunger rod, a female screw of the gasket made of a rubber elastic material such as butyl rubber or an elastomer and a male of a plunger rod made of plastic such as polypropylene, for example, are used. Screwing with screws is widely used. This is because when the plunger rod is press-fitted into the gasket as in the case of a normal syringe, the pressure may cause the chemical solution to leak from the gasket or the tip nozzle.

However, in the conventional connection between the gasket and the plunger rod by direct screwing, if the plunger rod is turned in the anti-screw direction during use, the screwing may be loosened. If the screw is loosened, the plunger rod may fall off from the gasket when a load is applied to the plunger rod, such as when using it with a syringe pump, and the drug solution may be rapidly administered to the patient.

In order to prevent such a plunger rod from falling off, the coupling between the gasket and the plunger rod has been studied, and an improved coupling mechanism has been proposed. For example, a gasket having an inner space with a closed tip and an opening having a diameter smaller than the diameter of the inner space at the base end, and a plunger rod having a male screw-shaped protrusion at the tip. A plunger configured to engage in a loosely fitted state when the protrusion exceeds the opening and enters the inner space has been proposed (Patent Document 1).

Further, a gasket on which a female screw is formed, a coupler on which a male screw to be screwed with the female screw is formed, a bottom rod connected from the base end side of the coupler, and a stopper formed on the coupler. The bottom rod includes an engaging portion formed on the bottom rod that engages with the stopper by rotation of the bottom rod in the screwing direction, and the stopper elastically deforms when it hits the engaging portion from the anti-screw direction. A prefilled syringe has also been proposed in which the gasket and the coupler are not loosened even when the bottom rod is rotated in the anti-screw direction by not engaging with the engaging portion (Patent Document 2).

JP-A-2007-202822 Japanese Unexamined Patent Publication No. 2008-307237

However, in a structure as in Patent Document 1, it is expected that the plunger rod will easily fall off from the gasket when the plunger rod is rotated in the anti-screw direction only with the male screw-shaped protrusion. Therefore, it is necessary to form an engaging portion that engages with the opening at the base end end of the male screw-shaped protrusion, but if such an engaging portion is formed, the plan When the jar rod is screwed into the gasket, the engaging portion may deform the gasket and the filled chemical solution may leak out. Further, in the structure as in Patent Document 2, since the gasket and the coupler are joined by screwing with screws, the coupler may rotate due to vibration during manufacturing or transportation, and the screwing may be loosened.

Therefore, the present invention has been made to solve the above problems, and an object of the present invention is to provide a plunger capable of preventing leakage of chemicals due to deformation of the gasket and loosening of the screw between the gasket and the plunger rod. To do.

A plunger according to the present invention comprises a bottom rod, a coupler that engages the bottom rod, and a gasket that engages the coupler, the bottom rod being able to idle in the first direction with respect to the coupler and the coupler. And the gasket are configured to engage in a loosely fitted state.

Preferably, the bottom rod has a first engaging portion, the coupler has a second engaging portion capable of contacting the first engaging portion, and the first engagement when the bottom rod is rotated in the first direction. The joint portion can idle with respect to the second engaging portion while abutting on the second engaging portion.

Preferably, at least one of the first engaging portion and the second engaging portion is elastically deformed in a state where the first engaging portion is in contact with the second engaging portion.

Further, the coupler has a male screw-shaped protrusion formed at the tip thereof, and the gasket has an internal space whose tip is closed, and an opening having a diameter smaller than the diameter of the internal space is formed at the base end. When the screw-shaped protrusion crosses the opening and enters the internal space, the coupler and the gasket are configured to engage in a loosely fitted state with the male screw-shaped protrusion accommodated in the internal space. ..

A syringe according to the present invention comprises any of the plungers described above.
A prefilled syringe according to the present invention comprises any of the plungers described above.

The plunger of the present invention is formed of a bottom rod, a coupler, and a gasket, and even if the bottom rod is rotated in the first direction, the bottom rod idles with respect to the coupler, so that the coupler does not rotate. That is, since the rotational force of the bottom rod is not transmitted to the engaging portion between the coupler and the gasket, the coupler and the gasket do not fall off due to the rotation of the bottom rod. Therefore, unlike Patent Document 1, it is not necessary to form an engaging portion that engages with the opening of the gasket at the base end side end of the thread of the male screw-shaped protrusion formed at the tip of the coupler. Since the gasket is not extremely deformed when the coupler is screwed into the gasket, the filled chemical solution does not leak out. Further, since the coupler and the gasket are configured to engage in a loosely fitted state, there is no possibility that the engagement will be loosened due to vibration during manufacturing or transportation.

It is a perspective view of the prefilled syringe which has a plunger according to Embodiment 1 of this invention. It is sectional drawing along the line II-II in FIG. FIG. 3 is an exploded perspective view of a prefilled syringe having a plunger shown in FIG. It is a perspective view of the barrel shown in FIG. It is a perspective view of the gasket shown in FIG. It is a perspective view of the coupler shown in FIG. It is a perspective view of the coupler shown in FIG. It is a perspective view of the bottom rod shown in FIG. It is sectional drawing along the IX-IX line in FIG. It is sectional drawing which shows the bottom rod further rotated from the state shown in FIG. It is sectional drawing which shows the bottom rod further rotated from the state shown in FIG. It is sectional drawing which shows the bottom rod further rotated from the state shown in FIG. It is sectional drawing which shows the bottom rod further rotated from the state shown in FIG. It is sectional drawing of the prefilled syringe which has a plunger according to Embodiment 2 of this invention. FIG. 6 is an exploded perspective view of a prefilled syringe having a plunger shown in FIG. It is a perspective view of the coupler shown in FIG. It is a perspective view of the coupler shown in FIG. It is a perspective view of the bottom rod shown in FIG. It is sectional drawing along the XIX-XIX line in FIG. It is sectional drawing of the prefilled syringe which has a plunger according to Embodiment 3 of this invention. It is an exploded perspective view of the prefilled syringe having the plunger shown in FIG. It is a perspective view of the coupler shown in FIG. It is a perspective view of the coupler shown in FIG. It is a perspective view of the bottom rod shown in FIG. It is sectional drawing along the line XXV-XXV in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
(Explanation of the overall configuration)
As shown in FIGS. 1 to 3, the prefilled syringe 1 includes a barrel 3 provided at the tip, a gasket 4 inserted into the barrel 3, a coupler 5 fitted to the gasket 4, and a bottom rod 6 fitted to the coupler 5. And have. In this embodiment, the case where the syringe is a prefilled syringe 1 is shown, but it is also possible to apply the present invention to a normal syringe in which a drug is not sealed in the syringe.

Mainly as shown in FIG. 4, an injection needle connecting portion 31 that opens is formed at the tip of the barrel 3. The base end of the barrel 3 is open, and a flange 32 is provided on the base end outer wall. A cap (not shown) is attached to the injection needle connection portion 31, and the opening is sealed.

Mainly as shown in FIG. 5, the gasket 4 is housed in a liquid-tight and slidable manner from the base end of the barrel 3. The space of the barrel 3 partitioned by the cap and the gasket 4 is filled with the chemical solution 7. An internal space 411 is formed at the base end of the gasket 4. An opening 412 communicating with the internal space 411 is provided at the base end of the gasket 4.

The gasket 4 is a rubber elastic body, and a material exhibiting rubber elasticity used in a normal gasket for a syringe can be used. Since the rubber elastic body is liquid-tight, butyl rubber, butadiene rubber, isoprene rubber, silicone rubber, thermoplastic elastomer, silicone elastomer and the like can be used.

As shown primarily in FIGS. 6 and 7, the coupler 5 has a male screw 51 that is inserted into the interior space 411. The male screw 51 is inserted into the internal space 411 and the male screw 51 is engaged with the gasket 4. The coupler 5 is connected to the base end of the gasket 4.

The coupler 5 has a gasket support portion 53. The gasket support portion 53 is provided with a connecting hole 52. The centers of the male screw 51 and the connecting hole 52 are provided coaxially. To engage the gasket 4 with the tip of the coupler 5, the male screw 51 is brought into contact with the opening 412 of the gasket 4 and the male screw 51 is rotated in the screwing direction. As a result, the male screw 51 is screwed into the opening 412, and finally, as shown in FIG. 2, the male screw 51 is housed in the internal space 411.

A cylindrical accommodating portion 54 is formed on the base end side of the gasket support portion 53. An elastically deformable stopper 8 is formed on the side wall of the accommodating portion 54, and an engaging claw 81 formed toward the inside of the accommodating portion 54 is formed at the tip of the stopper 8.

The bottom rod 6 and the coupler 5 are axially connected by inserting a ridge 61 formed at the tip of the bottom rod 6 into the connecting hole 52.

Mainly as shown in FIG. 8, the bottom rod 6 has a core portion 62. A ridge 61 is formed at the tip of the core portion 62. The core portion 62 is accommodated inside the accommodating portion 54. A core portion is formed at the tip of the bottom rod body 63. A collar 632 is formed at the base end of the bottom rod body 63.

The shafts of the coupler 5 and the bottom rod 6 are shaken by the portion where the connecting hole 52 and the ridge 61 are engaged and the portion where the base end of the accommodating portion 54 and the tip of the bottom rod body 63 are in contact with each other. It is stably connected and attached. The core portion 62 is provided with an engaging piece 9 that serves as an engaging portion that engages with the stopper 8 by a rotation operation.

The plunger 60 is formed of a coupler 5, a bottom rod 6 and a gasket 4. The material used for the plunger 60 is not particularly limited as long as it can be used for a syringe and the stopper 8 can have a slight elasticity, and a known material can be used. A thermoplastic resin is preferable because it is easy to mold. At this time, the materials of the plunger 60 do not have to be all the same.

The bottom rod 6, which is a component of the base end of the plunger 60, is connected to the coupler 5 with its axis aligned. An engaging piece 9 is formed on the core portion 62 of the bottom rod 6. A stopper 8 is provided on the side wall of the accommodating portion 54 of the coupler 5.

(Rotation of bottom rod)
As shown in FIG. 9, even if the bottom rod 6 rotates in the first direction (anti-screw direction) indicated by the arrow R1, the engaging piece 9 does not engage with the engaging claw 81. The engaging piece 9 and the engaging claw 81 are engaged with each other by rotating the bottom rod 6 in the second direction (screw direction).

As shown in FIGS. 9 to 13, when the engaging piece 9 rotating in the anti-screw direction hits the engaging claw 81, the engaging claw 81 is pushed outward from the center by the engaging piece 9 and becomes the stopper 8. It does not engage with the engaging piece 9. Therefore, even if the bottom rod 6 is rotated in the anti-screw direction, the coupler 5 does not rotate following the bottom rod 6.

When the bottom rod 6 rotates in the second direction (screw direction) indicated by the arrow R2, the stepped portion 9a of the engaging piece 9 engages with the engaging claw 81 in the state shown in FIG. When the engaging piece 9 is rotated in the direction indicated by the arrow R2, the engaging claw 81 and the coupler 5 also rotate in the screwing direction. Since the male screw 51 of the coupler 5 rotates in the screwing direction, the male screw 51 rotates in the screwing direction. Therefore, at the time of manufacturing the syringe, by rotating the bottom rod 6 in the screwing direction, the male screw 51 of the coupler 5 rotates in the screwing direction, exceeds the opening 412 of the gasket 4, and is accommodated in the internal space 411. ..

The bottom rod 6 can idle in the first direction with respect to the coupler 5, and the coupler 5 and the gasket 4 are in a loosely fitted state (the coupler 5 can rotate freely with respect to the gasket 4, but the gasket from the coupler 5). Engage in a state where a force is required to separate 4 in the axial direction). The bottom rod 6 has an engaging piece 9 as a first engaging portion, the coupler 5 has an engaging claw 81 as a second engaging portion capable of contacting the engaging piece 9, and the bottom rod 6 is provided. When rotated in the first direction, the engaging piece 9 can idle with respect to the engaging claw 81 while abutting on the engaging claw 81. When the engaging piece 9 is in contact with the engaging claw 81, the engaging claw 81 is elastically deformed. The coupler 5 has a male screw 51 formed at its tip, and the gasket 4 has an internal space 411 whose tip is closed, and an opening 412 having a diameter smaller than the diameter of the internal space 411 is formed at the base end. When the 51 enters the internal space 411 beyond the opening 412, the coupler 5 and the gasket 4 are engaged in a loosely fitted state with the male screw 51 housed in the internal space 411.

(effect)
In this way, the coupler 5 does not rotate even if the bottom rod 6 is rotated in the anti-screw direction. Therefore, even if a rotational force in the anti-screw direction is applied to the base end of the plunger 60, the coupler 5 and the gasket 4 are connected. The connection will not loosen. Therefore, even if the tip shape of the coupler 5 is a simple male screw shape, the connection between the coupler 5 and the gasket 4 is not loosened, and when the coupler 5 having such a tip shape is screwed into the gasket 4. Does not extremely deform the gasket 4, so that the filled chemical solution 7 does not leak out.

Since the engagement between the coupler 5 and the gasket 4 is in a loose fitting state, there is no possibility that the engagement will be loosened due to vibration during manufacturing and transportation.

The shape of the connecting hole 52 formed in the coupler 5 is formed in a tapered shape in which the diameter is sequentially reduced from the base end side, and similarly, the ridge 61 at the tip of the bottom rod 6 is formed in a tapered shape in which the diameter is sequentially reduced toward the tip. This facilitates the entry of the ridge 61 formed at the tip of the bottom rod 6 into the connecting hole 52 of the coupler 5 when the coupler 5 and the bottom rod 6 are connected. On the other hand, once connected, the surface on the distal end side located around the connecting hole 52, which is both perpendicular to the shaft, and the surface on the proximal end side of the ridge 61 engage with each other, so that the coupler 5 And the bottom rod 6 will not be disconnected. Further, since the coupler 5 and the bottom rod 6 are rotatably connected as shown here, the bottom rod 6 is freely connected to the coupler 5 as long as the stopper 8 and the engaging piece 9 are not engaged. Can be rotated.

(Embodiment 2)
As shown in FIGS. 14 to 19, in the prefilled syringe 1 having the plunger 60 according to the second embodiment, the shapes of the engaging piece 9 and the engaging claw 81 are different from those of the first embodiment.

The engaging claws 81 are mainly plate-shaped as shown in FIG. 17, and a pair of engaging claws 81 are arranged in the accommodating portion 54 in parallel with each other at a distance. The pair of engaging claws 81 are formed so as to extend in the axial direction.

The engaging piece 9 is arranged on the outer periphery of the core portion 62. When the engaging piece 9 rotates in the anti-screw direction (first direction) indicated by the arrow R1 from the position shown in FIG. 19, the curved portion of the engaging piece pushes the engaging claw 81 outward. By elastically deforming the engaging claw 81 outward, the engaging piece can rotate in the direction indicated by the arrow R1.

When the engaging piece 9 rotates in the screwing direction (second direction) indicated by the arrow R2 from the position shown in FIG. 19, the stepped portion 9a of the engaging piece 9 comes into contact with the engaging claw 81. Since the step portion 9a cannot push the engaging claw 81 outward, the rotation of the engaging piece 9 is transmitted to the engaging claw 81 while the step portion 9a of the engaging piece 9 is in contact with the engaging claw 81. To. As a result, the engaging claw 81 rotates together with the engaging piece 9.

(Embodiment 3)
As shown in FIGS. 20 to 25, in the prefilled syringe 1 having the plunger 60 according to the third embodiment, the shapes of the engaging piece 9 and the engaging claw 81 are different from those of the first embodiment.

Mainly as shown in FIG. 23, the engaging claw 81 is formed on the wall surface forming the accommodating portion 54. In the first and second embodiments, the engaging piece 9 is allowed to rotate by changing the position of the engaging claw 81. However, in the third embodiment, the engaging claw 81 is not deformed, and the engaging piece 9 side is elastically deformed.

As shown in FIGS. 24 and 25, the engaging piece 9 extends in the circumferential direction. One end of the engaging piece 9 is connected to the core 62 and the other end is a free end. Therefore, the other end is easily elastically deformed in the radial direction.

When the engaging piece 9 rotates in the anti-screw direction (first direction) indicated by the arrow R1 from the position shown in FIG. 25, the engaging piece 9 is pressed by the engaging claw 81 and elastically deforms inward in the radial direction. As a result, the engaging piece 9 can rotate in the direction indicated by the arrow R1.

When the engaging piece 9 rotates in the screwing direction (second direction) indicated by the arrow R2 from the position shown in FIG. 25, the free end of the engaging piece 9 comes into contact with the engaging claw 81. Since the free end cannot get over the engaging claw 81, the rotation of the engaging piece 9 is transmitted to the engaging claw 81 while the free end (tip) portion of the engaging piece 9 is in contact with the engaging claw 81. .. As a result, the engaging claw 81 rotates together with the engaging piece 9.

The embodiments and examples disclosed this time should be considered to be exemplary and not restrictive in all respects. The scope of the present invention is shown by the scope of claims rather than the above description, and it is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

The present invention may be applied in the field of syringes, especially prefilled syringes in which a drug solution is encapsulated in a barrel.

1 Prefilled Syringe, 2 Caps, 3 Barrels, 4 Gaskets, 5 Couplers, 6 Bottom Rods, 7 Chemicals, 8 Stoppers, 9 Engagement Pieces, 9a Steps, 31 Injection Needle Connections, 32 Flange, 51 Male Screws, 52 Connections Holes, 53 gasket supports, 54 containments, 60 plungers, 61 ridges, 62 cores, 63 bottom rod bodies, 81 engaging claws, 411 internal spaces, 412 openings, 632 flanges.

Claims (5)

With the bottom rod
A coupler that engages with the bottom rod
With a gasket that engages with the coupler
The bottom rod can idle in the first direction with respect to the coupler, and the coupler and the gasket can freely rotate with respect to the gasket, but the gasket can be axially rotated from the coupler. It is configured to engage in a loosely fitted state that requires force to release .
The coupler has a male screw-shaped protrusion formed at its tip, and the gasket has an internal space whose tip is closed, and an opening having a diameter smaller than the diameter of the internal space is formed at the base end. When the male screw-shaped protrusion crosses the opening and enters the internal space, the coupler and the gasket are engaged in a loosely fitted state with the male screw-shaped protrusion accommodated in the internal space. A plunger that is configured to fit . The bottom rod has a first engaging portion, the coupler has a second engaging portion capable of contacting the first engaging portion, and when the bottom rod is rotated in the first direction, the said The plunger according to claim 1, wherein the first engaging portion can idle with respect to the second engaging portion while abutting on the second engaging portion. The plan according to claim 2, wherein at least one of the first engaging portion and the second engaging portion is elastically deformed in a state where the first engaging portion is in contact with the second engaging portion. jar. A syringe provided with the plunger according to any one of claims 1 to 3. A prefilled syringe comprising the plunger according to any one of claims 1 to 3.