The present disclosure generally relates to a plunger kit, a syringe kit, and a prefilled syringe.
A prefilled syringe used for injecting liquid medicine includes a syringe main body including a liquid medicine storage chamber, liquid medicine filled in the liquid medicine storage chamber, a cap attached to a nozzle of the syringe main body, a piston (also referred to as a piston or a gasket) slidably fitted inside of the syringe main body, and a plunger rod for sliding the piston in an axial direction. Such a prefilled syringe is assembled by filling the liquid medicine inside the syringe main body with the cap attached to the nozzle, capping only the piston first to seal the liquid medicine in the syringe main body, and pushing a tip end part of the plunger rod into a recess of a base end side of the capped piston to join the plunger rod and the piston.
When a plunger is coupled to the piston, it is necessary to push the plunger so as to press the plunger toward a tip end side of the syringe. At this time, there is a possibility that as the piston moves that liquid medicine leaks from the syringe.
In order to solve such a problem, WO 2009/011214 A discloses a syringe plunger assembly for injector in which a cylindrical hole opened on a base end side is provided in a piston, and a male screw structure is provided at a tip end part of a plunger rod.
However, in the syringe plunger assembly of WO 2009/011214 A, the male screw structure having an outer diameter larger than an inner diameter of the male screw structure is pushed into a hole of the piston, and the male screw structure is caused to bite into an inner wall of the hole, thereby coupling the plunger rod with the piston. Therefore, in order to help prevent the plunger rod from falling off from the piston during transportation or the like, it is necessary that an outer diameter of the male screw structure of the plunger rod is sufficiently larger than an inner diameter of the hole of the piston. However, in this case, there is a problem that the piston moves because the plunger rod is forcibly pushed into the hole of the piston at the time of coupling.
A plunger kit, a syringe kit, and a prefilled syringe are disclosed, which are capable of ensuring joint strength between a plunger rod and a piston, enabling mounting of the plunger rod to the piston without moving the piston, and preventing the plunger rod from falling off from the piston during transportation, or the like, of the prefilled syringe.
One aspect of the following disclosure is a plunger kit including a piston to be slidably inserted into a liquid medicine storage chamber of a syringe main body part, and a plunger rod mountable to the piston, in which the plunger rod has a rod main body that extends in an axial direction and transmits drive force to the piston, and a mounting part that projects from a tip end part of the rod main body and is for mounting the plunger rod to the piston, the mounting part has a shaft part that projects from the tip end of the rod main body to a tip end side with a substantially constant diameter, an engagement part that projects from a tip end part of the shaft part in a radial direction and forms an engagement surface formed substantially perpendicular to the axial direction, and a conical part disposed on a tip end side of the engagement part and reduced in diameter in a tapered manner toward a tip end, a recess is formed on the piston, the recess having an opening part opened in a base end direction, a narrow part communicating with a tip end side of the opening part and extending in the axial direction, and a storage part communicating with a tip end side of the narrow part and capable of storing the engagement part and the conical part, the storage part being formed in a hollow shape, the piston has a first side wall part forming the storage part, and a second side wall part forming the narrow part and thicker than the first side wall part, length of the second side wall part in the axial direction is 10% to 40% of an entire length of the piston in the axial direction, and a cut-out part obtained by cutting out a part in a circumferential direction is formed on the engagement part of the plunger rod.
Another aspect of the following disclosure is a syringe kit including the plunger kit of the above-described aspect, and a syringe main body part having a liquid medicine storage chamber that stores liquid medicine, a nozzle provided on a tip end of the liquid medicine storage chamber, and a cap that seals a tip end opening part of the nozzle, in which the piston is slidable in the liquid medicine storage chamber.
Still another aspect of the present disclosure is a prefilled syringe including the syringe kit of the above-described aspect, and liquid medicine filled in the liquid medicine storage chamber, in which the piston is disposed so as to be slidable in the liquid medicine storage chamber.
In accordance with an aspect, a plunger kit comprising: a piston configured to be slidably inserted into a liquid medicine storage chamber of a syringe main body part, and a plunger rod mountable to the piston; wherein the plunger rod has a rod main body that extends in an axial direction and transmits drive force to the piston, and a mounting part that projects from a tip end of the rod main body and is for mounting the plunger rod to the piston; the mounting part includes a shaft part that projects from a tip end part of the rod main body to a tip end side with a substantially constant diameter, an engagement part that projects from a tip end part of the shaft part in a radial direction and forms an engagement surface formed substantially perpendicular to the axial direction, and a conical part disposed on a tip end side of the engagement part and reduced in diameter in a tapered manner toward a tip end; a recess is formed on the piston, the recess having an opening part opened in a base end direction, a narrow part communicating with a tip end side of the opening part and extending in the axial direction, and a storage part communicating with a tip end side of the narrow part and capable of storing the engagement part and the conical part, the storage part being formed in a hollow shape; and the piston has a first side wall part forming the storage part, and a second side wall part forming the narrow part and thicker than the first side wall part.
In accordance with another aspect, a prefilled syringe comprising: a plunger kit, the plunger kit comprising: a piston configured to be slidably inserted into a liquid medicine storage chamber of a syringe main body part, and a plunger rod mountable to the piston; wherein the plunger rod has a rod main body that extends in an axial direction and transmits drive force to the piston, and a mounting part that projects from a tip end of the rod main body and is for mounting the plunger rod to the piston; the mounting part includes a shaft part that projects from a tip end part of the rod main body to a tip end side with a substantially constant diameter, an engagement part that projects from a tip end part of the shaft part in a radial direction and forms an engagement surface formed substantially perpendicular to the axial direction, and a conical part disposed on a tip end side of the engagement part and reduced in diameter in a tapered manner toward a tip end; a recess is formed on the piston, the recess having an opening part opened in a base end direction, a narrow part communicating with a tip end side of the opening part and extending in the axial direction, and a storage part communicating with a tip end side of the narrow part and capable of storing the engagement part and the conical part, the storage part being formed in a hollow shape; and the piston has a first side wall part forming the storage part, and a second side wall part forming the narrow part and thicker than the first side wall part; and a syringe main body part having a liquid medicine storage chamber with a liquid medicine, a nozzle provided on a tip end of the liquid medicine storage chamber, and a cap that seals a tip end opening part of the nozzle.
According to the plunger kit, syringe kit, and prefilled syringe in the above-described aspects, the plunger rod can be mounted to the piston without moving the piston, and the piston does not come out of the plunger during transportation, or the like, of the prefilled syringe.
Set forth below with reference to the accompanying drawings is a detailed description of embodiments of a plunger kit, a syringe kit, and a prefilled syringe. Note that since embodiments described below are preferred specific examples of the present disclosure, although various technically preferable limitations are given, the scope of the present disclosure is not limited to the embodiments unless otherwise specified in the following descriptions. In addition, in the following description, a direction in which a nozzle 12c of a syringe kit 10 is formed is referred to as a tip end side or a tip end direction, and a direction opposite to the nozzle 12c of the syringe kit 10 is referred to as a base end side or a base end direction.
As illustrated in
A nozzle 12c is formed at a tip end of the liquid medicine storage chamber 12a, and a connector 16 is attached to an outer peripheral part of the nozzle 12c. A cap 18 is screwed to the connector 16, and a tip end opening part of the nozzle 12c can be sealed by the cap 18. That is, a tip end side of the liquid medicine storage chamber 12a is sealed by the cap 18. A piston 22 is inserted into the liquid medicine storage chamber 12a slidably in the axial direction. A base end side of the liquid medicine storage chamber 12a is sealed by the piston 22.
As illustrated in
The piston 22 can include, for example, a medical rubber material, and includes a main body part 22a having a columnar shape, ring-shaped protrusions 22b, 22c formed on side portions of the main body part 22a, and a recess 24 as illustrated in
As illustrated in
In accordance with an exemplary embodiment, the narrow part 28 formed on the inner side of the second side wall part 28a can be reduced in diameter to be smaller than the opening part 26. The narrow part 28 can be formed to have a substantially constant inner diameter and extend in the axial direction by the same length as the second side wall part 28a. By setting the narrow part 28 to have a constant inner diameter in this manner, a mounting part 32 can rather smoothly pass through the narrow part 28. In addition, the inner diameter of the narrow part 28 is slightly larger than an outer diameter of a shaft part 34 (refer to
The narrow part 28 is formed such that length of the narrow part 28 in the axial direction can be, for example, 10% to 40% of length of the piston 22 in the axial direction. Specifically, the length of the narrow part 28 can be set to about 1 mm to 5 mm. By being formed in this manner, the narrow part 28 of the piston 22 is less likely to be deformed by tensile force when the plunger rod 14 is pulled out, and sufficient joint strength can be exerted against the tensile force. It should be noted that the length of the narrow part 28 is preferably, for example, 1 mm to 3 mm.
In addition, a ring-shaped protrusion 22c is provided on an outer peripheral part of the second side wall part 28a that constitutes the narrow part 28. By providing the ring-shaped protrusion 22c on the outer peripheral part of the second side wall part 28a in this manner, the ring-shaped protrusion 22c is pressed against the liquid medicine storage chamber 12a when the mounting part 32 of the plunger rod 14 passes, and therefore the piston 22 is less likely to move, and displacement of the piston 22 can be prevented.
The storage part 30 is formed on an inner side of a first side wall part 30c. The first side wall part 30c is formed on a tip end side of the second side wall part 28a, and can be thinner in the radial direction than the second side wall part 28a. At a boundary between the first side wall part 30c and the second side wall part 28a, an abutting surface 30b1 is formed so as to rise substantially perpendicular to the axial direction.
The storage part 30 formed on the inner side of the first side wall part 30c can include a base part 30b formed to have an inner diameter substantially equal to an inner diameter of the opening part 26, and a reduced diameter part 30a formed on a tip end side of the base part 30b and reducing in diameter in a conical shape toward the tip end. In accordance with an exemplary embodiment, the base part 30b is formed to have an inner diameter larger than engagement parts 36 (refer to
The opening part 26 has a base end part 26a formed to have an inner diameter substantially the same as an outer diameter of the engagement parts 36 along an axis α1 direction and extending in the axis α1 direction by a predetermined length, and a tapered part 26b reduced in diameter from the base end part 26a toward the narrow part 28. The base end part 26a is configured to guide an axis of the engagement parts 36 of the plunger rod 14 to an axis α1 of the recess 24, the engagement parts 36 being formed in a tapered shape. The tapered part 26b guides the conical part 38 to a center of the axis α1 of the recess 24. With this arrangement, the axes of the plunger rod 14 and piston 22 can be aligned, and the engagement parts 36 of the mounting part 32 rather easily pass through the narrow part 28.
As illustrated in
In accordance with an exemplary embodiment, the shaft part 34 is a columnar part extending with a constant diameter from the piston abutting part 14c toward the tip end side in the axial direction. The shaft part 34 is formed to have a diameter substantially equal to or smaller than an inner diameter of the narrow part 28 in order to prevent the shaft part 34 from being caught by the narrow part 28 and the piston 22 from moving when being mounted to the piston 22. A diameter of the shaft part 34 is formed to be, for example, 1 mm to 5 mm. By providing the shaft part 34, the narrow part 28 extending with a constant diameter in the axial direction can be provided in the recess 24 of the piston 22, and strength of joint with the piston 22 in a pull-out direction can be improved.
The engagement parts 36 are parts formed to increase in diameter outward in the radial direction from the shaft part 34. As illustrated in
It should be noted that the number of cut-out parts 42 is not limited to two as in the illustrated examples, and a plurality of cut-out parts may be provided at regular intervals in the circumferential direction. In addition, the number of the engagement parts 36 is not limited to two, and three or more engagement parts 36 may be provided.
As illustrated in
As illustrated in
A plunger kit 15 and syringe kit 10 including the plunger rod 14 and piston 22 of the present embodiment are configured as described above, and operation of the plunger kit 15 and the syringe kit 10 will be described below.
As illustrated in
In the present embodiment, because the engagement parts 36 increased in diameter from the shaft part 34 are cut out in the circumferential direction by the first cut-out part 42a and the second cut-out part 42b, a portion of the narrow part 28 where the engagement parts 36 spread out can be further reduced. As a result, the mounting part 32 including the engagement parts 36 can be mounted to the recess 24 with relatively less pushing force. With this arrangement, the plunger rod 14 can be mounted to the piston 22 while preventing displacement of the piston 22 in the axial direction.
Thereafter, the plunger rod 14 is mounted to the piston 22, and as illustrated in
Although an example in which the syringe kit 10 is applied to the prefilled syringe 100 has been described above, the syringe kit 10 of the present embodiment is not limited to the prefilled syringe 100, and various aspects can be taken. For example, as illustrated in
The plunger kit 15, syringe kit 10, and prefilled syringe 100 of the present embodiment have the following effects.
The plunger kit 15 of the present embodiment is a plunger kit 15 including the piston 22 to be slidably inserted into the liquid medicine storage chamber 12a of the syringe main body part 12, and the plunger rod 14 mountable to the piston 22, in which the plunger rod 14 has the rod main body 14a that extends in the axial direction and transmits drive force to the piston 22, and the mounting part 32 that projects from a tip end part of the rod main body 14a and is for mounting the plunger rod 14 to the piston 22, the mounting part 32 has the shaft part 34 that projects from the tip end part of the rod main body 14a to a tip end side with a substantially constant diameter, the engagement part 36 that projects from the tip end part of the shaft part 34 in the radial direction and forms the engagement surface 40 formed substantially perpendicular to the axial direction, and the conical part 38 that is disposed on a tip end side of the engagement part 36 and reduced in diameter in a tapered manner toward the tip end, the recess 24 is formed on the piston 22, the recess 24 having the opening part 26 opened in the base end direction, the narrow part 28 communicating with the tip end side of the opening part 26 and extending in the axial direction, and the storage part 30 communicating with a tip end side of the narrow part 28 and capable of storing the engagement part 36 and the conical part 38, the storage part 30 being formed in a hollow shape, the piston 22 has the first side wall part 30c forming the storage part 30 and the second side wall part 28a forming the narrow part 28 and thicker than the first side wall part 30c, length of the second side wall part 28a in the axis α1 direction can be, for example, 10% to 40% of an entire length of the piston 22 in the axis α1 direction, and cut-out parts 42 obtained by cutting out a part in the circumferential direction are formed on the engagement part 36 of the plunger rod 14.
With the above-described configuration, as compared to a case where the engagement parts 36 are formed in an entire area in the circumferential direction, resistance of when the plunger rod 14 is mounted to the piston 22 can be reduced, and the plunger rod 14 can be mounted to the piston 22 with a relatively small pushing force. With this arrangement, the plunger rod 14 can be mounted to the piston 22 without displacing the piston 22. In addition, because the piston 22 includes the second side wall part 28a formed to be thick and extend in the axial direction by a predetermined length, and the narrow part 28, the engagement parts 36 of the plunger rod 14 can be reliably held. With this arrangement, even if force in the base end direction acts on the plunger rod 14 during transportation or the like, the plunger rod 14 does not easily fall off from the piston 22.
In the above-described plunger kit 15, the narrow part 28 may extend with a substantially uniform diameter. With this arrangement, the engagement parts 36 can rather smoothly pass through the narrow part 28, and pressing force of when the plunger rod 14 is mounted can be reduced.
In the above-described plunger kit 15, the outer diameter of the shaft part 34 may be equal to or smaller than the inner diameter of the narrow part 28. With this arrangement, the shaft part 34 can be prevented from being caught by the narrow part 28, and the piston 22 can be prevented from moving.
In the above-described plunger kit 15, the piston 22 may have the ring-shaped protrusion 22c on an outer peripheral surface of the second side wall part 28a, the ring-shaped protrusion 22c abutting against the inner wall of the liquid medicine storage chamber 12a of the syringe main body part 12. With this arrangement, when the engagement parts 36 pass through the narrow part 28, the ring-shaped protrusion 22c is pressed against the inner wall of the liquid medicine storage chamber 12a as the narrow part 28 is spread out. As a result, the piston 22 is less likely to move, and movement of the piston 22 accompanying mounting of the plunger rod 14 can be prevented.
In the above-described plunger kit 15, the opening part 26 of the recess 24 may have the base end part 26a extending along the axis α1 direction by a predetermined length with an inner diameter substantially the same as the outer diameter of the engagement parts 36, and the tapered part 26b reduced in diameter from the base end part 26a toward the narrow part 28. With this arrangement, when the plunger rod 14 is inserted into the recess 24, the engagement parts 36 are guided by the base end part 26a, and the conical part 38 is guided by the tapered part 26b, by which an axis of the plunger rod 14 and the axis of the piston 22 coincide with each other. With this arrangement, the engagement parts 36 rather easily pass through the narrow part 28, and movement of the piston 22 can be prevented.
In the above-described plunger kit 15, the engagement parts 36 may have a shape that decreases in size toward the tip end until the outer diameter of the engagement parts 36 substantially coincides with the outer diameter of the conical part 38. With this arrangement, when the mounting part 32 is inserted into the recess 24, the engagement parts 36 guided by the conical part 38 can rather smoothly pass through the narrow part 28.
In the above-described plunger kit 15, a pair of engagement parts 36 may be provided spaced apart from each other, for example, by 180° in the circumferential direction.
In this case, a pair of cut-out parts 42a, 42b is formed across the shaft part 34, and a pair of engagement parts 36 is formed to project in an arrowhead shape. With such a configuration, when the plunger rod 14 is mounted, only the engagement parts 36, which thinly project, thrust the narrow part 28 of the piston 22, and the cut-out parts 42a, 42b can pass through the narrow part 28 without receiving resistance. With this arrangement, resistance of when the plunger rod 14 is mounted to the piston 22 is reduced, and the plunger rod 14 can be mounted to the piston 22 without displacing the piston 22.
In the above-described plunger kit 15, the cut-out parts 42a, 42b may be obtained by cutting out the engagement parts 36 within an area from the outer diameter of the engagement parts 36 to the outer diameter of the shaft part 34. With such a configuration, resistance of when the plunger rod 14 is mounted to the piston 22 can be reduced, and the plunger rod 14 can be mounted to the piston 22 without displacing the piston 22.
In addition, the syringe kit 10 and prefilled syringe 100 of the present embodiment include the above-described plunger kit 15. With this arrangement, displacement of the piston 22 when the plunger rod 14 is mounted to the piston 22 can be prevented, and, after the plunger rod 14 is mounted, the plunger rod 14 can be prevented from coming off the piston 22 in the prefilled syringe 100 during transportation.
As illustrated in
As illustrated in
As illustrated in
An engagement surface 44a and engagement surface 44b substantially perpendicular to an axial direction are formed at base ends of the engagement part 47 and engagement part 48, respectively. As illustrated by hatching in
The plunger kit 15A of the present embodiment includes the plunger rod 14A described above, and operation of the plunger kit 15A will be described below.
As illustrated in
The plunger kit 15A, syringe kit 10A, and prefilled syringe 100A of the present embodiment have the following effects.
In the plunger kit 15A of the present embodiment, the cut-out parts 45a, 45b can be formed to extend spirally in the axial direction, and a plurality of thread ridges can be formed on the engagement parts 47, 48. With this arrangement, the plunger rod 14A can be mounted to the piston 22 by operation that is a combination of pushing operation and screwing operation. With this arrangement, load of when the plunger rod 14A is mounted can be dispersed to load in the rotation direction, and therefore displacement of the piston 22 when the plunger rod 14A is mounted can be effectively reduced.
In the above-described plunger kit 15A, a pair of engagement surfaces 44a, 44b may be provided spaced apart from each other, for example, by 180° in the circumferential direction. That is, it is possible to configure a double-start thread in which two engagement surfaces 44a and 44b serving as base ends of the thread ridges are formed. Such a configuration may be preferable, because the engagement surfaces 44a, 44b to be engaged with the narrow part 28 of the piston 22 are increased in size, and therefore joint strength against load in a pull-out direction can be relatively ensured.
In addition, the syringe kit 10A and prefilled syringe 100A of the present embodiment include the above-described plunger kit 15A. With this arrangement, displacement of the piston 22 can be prevented when the plunger rod 14A is mounted to the piston 22, and, after the plunger rod 14A is mounted, the plunger rod 14A can be prevented from coming off the piston 22 during transportation.
As illustrated in
As illustrated in
The plunger rod 14B of the present embodiment is configured as described above, and operation of the plunger rod 14B will be described below.
As illustrated in
As illustrated in
The plunger kit 15B, syringe kit 10B, and prefilled syringe 100B of the present embodiment have the following effects.
The plunger kit 15B of the present embodiment includes the slit structure 50 formed over the conical part 38, the engagement parts 36, and the shaft part 34, and the engagement parts 36 are elastically deformable inward. With such a configuration, the engagement parts 36 can be elastically deformed inward when passing through the narrow part 28 of the piston 22, and therefore the plunger rod 14B can be mounted to the piston 22 with relatively less resistance. As a result, the plunger rod 14B can be mounted to the piston 22 while preventing movement of the piston 22.
In addition, because the syringe kit 10B and prefilled syringe 100B of the present embodiment include the above-described plunger kit 15B, displacement of the piston 22 can be prevented when the plunger rod 14B is mounted to the piston 22. In addition, after the plunger rod 14B is mounted, the plunger rod 14B can be prevented from coming off the piston 22 during transportation.
As illustrated in
As illustrated in
The plunger rod 14C of the present embodiment has the following effects.
In the plunger rod 14C of the present embodiment, the coating 54 for improving sliding performance is formed on the conical part 38 and the engagement parts 36A. With this arrangement, resistance of when the plunger rod 14C is mounted to a piston 22 can be reduced, and movement of the piston 22 can be prevented. It should be noted that the conical part 38 and engagement parts 36A of the present embodiment may be those described with reference to
As illustrated in
As illustrated in
In addition, as illustrated in
In addition, as illustrated in
As described above, in the present embodiment, the coating 60 for improving sliding performance is formed on the opening part 26 of the piston 22. With this arrangement, resistance of when the plunger rod 14 is mounted to the piston 22 can be reduced, and movement of the piston 22 can be prevented.
As illustrated in
As illustrated in
According to the plunger kit 15D, syringe kit 10D, and prefilled syringe 100D of the present embodiment, because most of an area in the engagement part 36 is cut out as the cut-out part 42D, when a narrow part 28 of the piston 22 is inserted, volume of the engagement part 36 that thrusts the narrow part 28 can be reduced, and the plunger rod 14D can be mounted to the piston 22 with relatively less pushing force. With this arrangement, the plunger rod 14D can be mounted without moving the piston 22. In addition, in the prefilled syringe 100D, the plunger rod 14D can be prevented from being pulled out from the piston 22 during transportation.
Although a plunger kit, a syringe kit, and a prefilled syringe are described above with the preferred embodiments, the plunger kit, the syringe kit, and the prefilled syringe are not limited to the embodiments described above, and it goes without saying that various modifications can be made without departing from the spirit of the present disclosure.
The detailed description above describes embodiments of a plunger kit, a syringe kit, and a prefilled syringe. The invention is not limited, however, to the precise embodiments and variations described. Various changes, modifications and equivalents may occur to one skilled in the art without departing from the spirit and scope of the invention as defined in the accompanying claims. It is expressly intended that all such changes, modifications and equivalents which fall within the scope of the claims are embraced by the claims.
Number | Date | Country | Kind |
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2019-065682 | Mar 2019 | JP | national |
This application is a continuation of International Application No. PCT/2020/011599 filed on Mar. 17, 2020, which claims priority to Japanese Patent Application No. 2019-065682 filed on Mar. 29, 2019, the entire content of both of which is incorporated herein by reference.
Number | Date | Country | |
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Parent | PCT/JP2020/011599 | Mar 2020 | US |
Child | 17487438 | US |