Syringe

Abstract

A syringe (1) comprises: a barrel (400) having a nozzle part (440) and a neck part (420) surrounding the nozzle part (440); a cap (100) rotatably attached to the barrel (400), the cap (100) having a first engagement part on the inner surface thereof; a double-ended needle (210); a hub (220) for holding the double-ended needle (210); and a sealing member (300) for sealing the nozzle part (440) of the barrel (400). The neck part (420) has, on the outer peripheral surface thereof, a second engagement part that engages with the first engagement part. One of the first engagement part and the second engagement part is a spiral groove, and the other is a first projection positioned within the spiral groove. Due to rotation of the cap (100), the cap (100) and the hub (220), guided by the first engagement part and the second engagement part, move in a direction toward the rear end of the barrel (400), and the rear end part of the double-ended needle (210) penetrates the sealing member (300).

Description

Syringe

[0001] The present disclosure relates to syringes.

[0002] A syringe capable of maintaining a sealed barrel until immediately before use on a patient has been proposed. The syringe disclosed in Japanese Patent Laid-Open Publication No. 2023-85825 (Patent Document 1) includes a barrel, a cap rotatably attached to the barrel around the central axis of the barrel as a rotation axis and having a spiral guide portion on its inner surface, a double-ended needle extending parallel to the central axis of the barrel, a hub having an engaging portion that holds the double-ended needle and engages with the guide portion and that is retractably attached to the barrel, and a sealing member that seals the distal end of the barrel and is located at the rear end of the double-ended needle. By rotating the cap, the engaging portion is guided by the guide portion, causing the hub to retract, and the rear end of the double-ended needle penetrates the sealing member.

[0003] In the syringe disclosed in Patent Document 1, the barrel can be kept sealed until the double-ended needle penetrates the sealing member, thereby preventing leakage of the medicinal liquid filled in the barrel.

[0004] JP 2023-85825 A

[0005] In the syringe disclosed in Patent Document 1, the hub and the double-ended needle held by the hub are retracted by rotating the cap. At this time, a gap is formed between the hub and the inner surface of the cap. This gap allows the internal space of the cap to communicate with the external environment. As a result, the tip of the double-ended needle is exposed to the external environment, posing a risk of contamination of the tip of the double-ended needle.

[0006] Therefore, the present disclosure has been made to solve the above-mentioned problems, and aims to provide a syringe that can isolate the internal space of a cap that covers a double-ended needle from the external environment until the cap is removed.

[0007] A syringe according to the present disclosure includes a barrel having a space for containing a drug solution, a nozzle portion communicating with the space, and an annular neck portion surrounding the nozzle portion; a cap rotatably attached to the barrel around the central axis of the barrel as a rotation axis and having a first engagement portion on its inner surface; a double-ended needle extending parallel to the central axis of the barrel; a hub that holds the double-ended needle and has at least its rear end located inside the neck; and a sealing member that seals the nozzle portion of the barrel and is located toward the rear end of the double-ended needle. The neck has a second engagement portion on its outer surface that engages with the first engagement portion. One of the first and second engagement portions is a spiral groove, and the other is a first protrusion located within the spiral groove. By rotating the cap around the central axis of the barrel as a rotation axis, the cap and the hub are guided by the first engagement portion and the second engagement portion and move toward the rear end of the barrel, and the rear end of the double-ended needle penetrates the sealing member.

[0008] According to the syringe of the present disclosure, the internal space of the cap that covers the double-ended needle can be isolated from the external environment until the cap is removed.

[0009] 1 is an exploded perspective view of a syringe according to an embodiment of the present disclosure; FIG. 2 is a longitudinal cross-sectional view of a cap according to an embodiment of the present disclosure; FIG. 3 is a perspective view of a cap according to an embodiment of the present disclosure; FIG. 4 is a perspective view of a hub with a needle according to an embodiment of the present disclosure; FIG. 5 is a perspective view of a barrel according to an embodiment of the present disclosure; FIG. 6 is a perspective view of a tip of a barrel according to an embodiment of the present disclosure; FIG. 7 is a perspective view illustrating the operation of a syringe according to an embodiment of the present disclosure; FIG. 8 is a cross-sectional view of a tip of a syringe according to an embodiment of the present disclosure; FIG. 9 is a perspective view of a syringe according to an embodiment of the present disclosure, with the cap omitted, illustrating the operation of the syringe according to an embodiment of the present disclosure; FIG. 10 is a cross-sectional view of a tip of a syringe according to an embodiment of the present disclosure; FIG. 11 is a perspective view of a syringe according to an embodiment of the present disclosure, with the cap omitted, illustrating the operation of the syringe according to an embodiment of the present disclosure;

[0010] Hereinafter, a syringe according to an embodiment of the present disclosure will be described with reference to the drawings. First, the structure of the syringe according to the embodiment of the present disclosure will be described with reference to mainly FIGS. 1 to 6.

[0011] Figure 1 is an exploded perspective view of a syringe according to the present embodiment. Syringe 1 according to the present embodiment includes cap 100, packing 190, needle hub 200, sealing member 300, barrel 400, and plunger 500. In the following description, the tip end side of cap 100 (upper side in Figure 1) is referred to as the tip end side, and the rear end side of plunger 500 (lower side in Figure 1) is referred to as the base end side. In addition, an axis extending through the center of barrel 400 of syringe 1 is referred to as the central axis, and the direction in which this central axis extends is referred to as the axial direction.

[0012] FIG. 2 is a vertical cross-sectional view of the cap in this embodiment, and FIG. 3 is a perspective view of the cap in this embodiment.

[0013] The cap 100 has a small diameter portion 110 located at the tip of the cap 100 and a large diameter portion 160 continuous with the small diameter portion 110. The inner diameter of the large diameter portion 160 is larger than the inner diameter of the small diameter portion 110. The outer shape of the cap 100 in this embodiment is merely an example.

[0014] The small diameter portion 110 is a cylindrical body with a closed tip end. When the cap 100 is attached to the syringe 1, the small diameter portion 110 covers the tip end side of the double-ended needle 210 of the needle hub 200. The small diameter portion 110 has a hollow portion 112, and the tip end side of the double-ended needle 210 is located in the hollow portion 112. A small diameter portion base end surface 114 that extends circumferentially and forms an annular shape is formed at the base end of the small diameter portion 110.

[0015] Anti-slip features 168, which are ribs extending in the axial direction, are provided on the outer circumferential surfaces of the small diameter portion 110 and the large diameter portion 160. A plurality of anti-slip features 168 are provided and arranged parallel to one another. The anti-slip features 168 function as a stopper when the user grips and rotates the cap 100 with their fingers.

[0016] A first protrusion 162 serving as a first engagement portion that protrudes inward is provided on the inner surface of the large diameter portion 160. The first protrusion 162 has a substantially parallelogram shape in a front view. The distal and proximal surfaces of the first protrusion 162 are inclined along the inner peripheral surface of the large diameter portion 160.

[0017] The large diameter portion 160 is provided with a second protrusion 122 that protrudes inward and serves as a fourth engagement portion. The second protrusion is rectangular in front view. The tip surface of the second protrusion 122 extends perpendicular to the central axis. In other words, the tip surface of the second protrusion 122 is not inclined.

[0018] As shown in Fig. 3, a pair of first protrusions 162 are provided at positions symmetrical with respect to the central axis. As shown in Fig. 3, a pair of second protrusions 122 are provided at positions symmetrical with respect to the central axis.

[0019] 4 is a perspective view of the needle hub of this embodiment. The needle hub 200 has a double-ended needle 210 and a hub 220. The double-ended needle 210 extends parallel to the central axis of the barrel 400. The double-ended needle 210 has a hollow portion extending in the axial direction. The distal end and proximal end of the double-ended needle 210 are sharply pointed tips 212, 214 (FIG. 1).

[0020] The hub 220 has a cylindrical hub body 224 and a needle holder 222 that protrudes distally from the distal end surface of the hub body 224. The needle holder 222 has a smaller diameter than the hub body 224, and the double-ended needle 210 passes through it. The needle holder 222 also extends proximally inside the hub body 224 (see Figures 8 and 12). The double-ended needle 210 is fixed to the hub body 224 by the needle holder 222.

[0021] The hub body 224 has a rib 230 that protrudes from the outer peripheral surface and serves as a third engagement portion. The rib 230 extends circumferentially on the outer peripheral surface of the hub body 224. The rib 230 has a discontinuous portion 232 that is a circumferentially interrupted portion. A pair of discontinuous portions 232 are provided at positions that are line-symmetrical about the central axis. The rib 230 has a stopper 234 that protrudes toward the base end and is adjacent to the discontinuous portion 232.

[0022] The hub body 224 has a third protrusion 228 protruding from the outer peripheral surface as a fifth engagement portion. The third protrusion 228 is provided on the outer peripheral surface near the base end of the hub body 224. The third protrusion 228 is rectangular in front view. A pair of third protrusions 228 is provided on the hub body 224. The pair of third protrusions 228 is provided in positions that are line-symmetrical with respect to the central axis of the barrel 400. A guide protrusion 226 is provided axially aligned with the third protrusion 228. A gap is provided between the tip end 228a of the third protrusion 228 and the guide protrusion 226. Although a gap is provided in this embodiment, this gap need not be provided.

[0023] A rubber packing 190 is provided between the hub body 224 and the base end surface 114 of the small diameter portion of the cap 100 (see FIGS. 1, 8, and 12). The rubber packing 190 is made of rubber and has an annular shape. The rubber packing 190 seals the gap between the hub 220 and the cap 100, isolating the internal space of the cap 100 from the external space. The rubber packing 190 also functions as a cushioning material between the hub 220 and the cap 100. Instead of the rubber packing 190, a packing made of, for example, a thermoplastic elastomer may be used.

[0024] The second protrusion 122, which serves as a fourth engagement portion provided on the cap 100, engages with the rib 230, which serves as a third engagement portion provided on the hub 220, thereby enabling the rubber gasket 190 to be held between the hub body 224 and the base end surface 114 of the small diameter portion of the cap 100.

[0025] In this embodiment, the fourth engagement portion provided on the cap 100 is the second protrusion 122, and the third engagement portion on the hub 220 is the rib 230, but these may be reversed. Specifically, the fourth engagement portion provided on the cap 100 may be a rib extending along the inner circumferential surface of the cap 100, and the third engagement portion on the hub 220 may be a protrusion, and they may engage with each other.

[0026] 5 and 6 are perspective views of the barrel according to this embodiment. The barrel 400 has a barrel body 410 and a neck 420. The barrel body 410 is a hollow cylinder, and is filled with a medicinal solution. The base end of the barrel body 410 is open. A flange 412 is provided at the base end of the barrel body 410.

[0027] The neck 420 is continuous with the tip of the barrel body 410. As shown in FIG. 6 , the outer diameter of the neck 420 is smaller than the outer diameter of the barrel body 410. However, the outer diameter of the neck 420 may be the same as the outer diameter of the barrel body 410. An opening 430 is provided near the base end of the neck 420. The opening 430 is rectangular in front view. The edge on the tip side of the opening 430 forms a seventh engagement portion 432 with which the third protrusion 228, which serves as the fifth engagement portion of the hub 220, engages. The hub 220 is fixed to the neck 420 by the engagement of the third protrusion 228 with the seventh engagement portion 432.

[0028] A second linear groove 428 serving as a sixth engagement portion is provided on the inner surface of the neck 420, extending axially between the tip of the neck 420 and the opening 430. The second linear groove 428 guides the third protrusion 228 provided on the hub body 224 from the tip of the neck 420 to the opening 430. The base end of the guide protrusion 226 is also located in the second linear groove 428. The third protrusion 228 serving as the fifth engagement portion is located inside the second linear groove 428 serving as the sixth engagement portion, thereby preventing the hub 220 from rotating relative to the neck 420 of the barrel 400. The guide protrusion 226 is also located in the second linear groove 428, thereby more reliably preventing the hub 220 from rotating relative to the neck 420 of the barrel 400.

[0029] In this embodiment, the fifth engagement portion is the third protrusion 228 and the sixth engagement portion is the second linear groove 428, but these may be reversed. Specifically, the fifth engagement portion provided on the hub 220 may be a linear groove, and the sixth engagement portion provided on the neck portion 420 of the barrel 400 may be the third protrusion, and they may be engaged with each other.

[0030] A spiral groove 436 serving as a second engagement portion is provided on the outer peripheral surface of the neck portion 420. The base end of the spiral groove 436 is connected to the opening 430. The tip end of the spiral groove 436 is connected to a guide groove 439 extending in the axial direction. An inclined protrusion 438 is provided inside the guide groove 439, inclined at the same angle as the spiral groove 436, and functions as a retainer.

[0031] A first protrusion 162 serving as a first engaging portion provided on the inner surface of the cap 100 is located inside the spiral groove 436 serving as a second engaging portion. When the cap 100 is rotated, the first protrusion 162 is guided by the spiral groove 436, causing the cap 100 to move toward the proximal end. At that time, the needle hub 200 and the rubber packing 190 also move toward the proximal end together with the cap 100.

[0032] In the present embodiment, the second engagement portion of neck 420 is the spiral groove 436, the first engagement portion provided on the inner surface of cap 100 is the first protrusion 162, and first protrusion 162 is guided by spiral groove 436, but these may be reversed. Specifically, the second engagement portion of neck 420 may be a protrusion, the first engagement portion provided on the inner surface of cap 100 may be a spiral groove, and the protrusion provided on the outer peripheral surface of neck 420 may engage with the spiral groove on the inner surface of cap 100.

[0033] A guide groove 439 located on the tip side of the spiral groove 436 is a groove for guiding the first protrusion 162 of the cap 100 to the spiral groove 436 during assembly. When the first protrusion 162 reaches the spiral groove 436, the inclined protrusion 438, which acts as a detent, holds the first protrusion 162 inside the spiral groove 436. This prevents the cap 100 from coming off the barrel 400.

[0034] When the first protrusion 162, guided by the spiral groove 436, reaches the base end of the spiral groove 436, the first protrusion 162 abuts against the abutment wall 434, preventing the cap 100 from rotating. This lets the user know that the cap 100 has been rotated to a predetermined position. At this time, the first protrusion 162 is positioned in front of the opening 430. The first protrusion 162 can pass through the first linear groove 424, which is continuous with the opening 430, toward the tip end.

[0035] When the cap 100 is rotated and the first protrusion 162 reaches the front of the opening 430, the second protrusion 122 is positioned at the discontinuous portion 232. The first protrusion 162 passes through the first linear groove 424 and the second protrusion 122 passes through the discontinuous portion 232, allowing the cap 100 to be removed from the barrel 400.

[0036] A nozzle portion 440 is provided inside the neck portion 420 (see FIG. 5). The nozzle portion 440 is configured in a cylindrical shape. The nozzle portion 440 has an internal flow path for the chemical solution, and the flow path communicates with the hollow portion of the barrel body 410. The nozzle portion 440 ejects the chemical solution filled inside the barrel 400 toward the tip.

[0037] The hub body 224 and the sealing member 300 are disposed within the neck portion 420 (see FIGS. 1, 8 and 12). The sealing member 300 is disposed between the hub body 224 and the nozzle portion 440.

[0038] The sealing member 300 has a cylindrical shape as shown in Figure 1. An annular rib 310 is provided on the tip side of the outer peripheral surface of the sealing member 300. The annular rib 310 is provided in two locations on the outer peripheral surface of the sealing member 300: at the tip end and on the base end side of the tip end. The provision of the annular rib 310 allows the hub body 224 and the sealing member 300 to slide against each other while maintaining a watertight seal.

[0039] The distal and proximal ends of the sealing member 300 are open. A partition 330 is provided in the middle of the sealing member 300 (see Figures 8 and 12). The partition 330 divides the interior of the sealing member 300 into a distal space and a proximal space. A nozzle portion 440 is fitted into the opening provided at the proximal end of the sealing member 300. The sealing member 300 is fitted into the interior of the hub body 224. The sealing member 300 seals the distal end of the nozzle portion 440 until the double-ended needle 210 penetrates through it. A material that will not react with the medicinal solution stored in the barrel 400 is selected for the sealing member 300. Examples of materials for the sealing member 300 include thermoplastic elastomers and rubber.

[0040] A plunger 500 is inserted into the barrel 400. The tip side of the plunger 500 is located in the hollow portion of the barrel 400. As shown in FIG.

[0041] Gasket 510 can slide while maintaining watertightness within the hollow portion of barrel 400. Materials are selected for barrel 400 and gasket 510 that do not react with the chemical solution stored in barrel 400 and that allow gasket 510 to slide liquid-tightly within barrel 400. Examples of materials for gasket 510 include thermoplastic elastomers and rubber.

[0042] A screw hole is provided at the base end of the gasket 510. A screw 522 at the tip of the plunger body 520 is threaded into the screw hole. This fixes the gasket 510 to the tip of the plunger body 520. The gasket 510 and the plunger body 520 may be molded integrally using synthetic resin or the like.

[0043] The plunger body 520 has a base end rib 526 provided at the base end of the plunger body 520. The plunger body 520 has reinforcing ribs 524. The plunger body 520 has a cross-shaped cross section formed by the four reinforcing ribs 524.

[0044] The operation of the syringe 1 of this embodiment will be described using Figures 7 to 14. Figure 7 is a perspective view illustrating the operation of the syringe in this embodiment. Figure 8 is a cross-sectional view of the tip portion illustrating the operation of the syringe in this embodiment. Figures 9 and 10 are perspective views illustrating the operation of the syringe in this embodiment, with the cap omitted. Figure 11 is a perspective view illustrating the operation of the syringe in this embodiment. Figure 12 is a cross-sectional view of the tip portion illustrating the operation of the syringe in this embodiment. Figures 13 and 14 are perspective views illustrating the operation of the syringe in this embodiment, with the cap omitted.

[0045] First, a description will be given of the assembly procedure for the syringe 1 of this embodiment. Note that, in the following description, a case will be described in which the syringe 1 of this embodiment is used as a prefilled syringe filled with a medicinal solution in advance, but the syringe 1 according to the present disclosure is not limited to being used as a prefilled syringe.

[0046] A rubber packing 190 is placed inside the cap 100 in advance. Next, the needle hub 200 is inserted into the cap 100. At this time, the second protrusion 122 of the cap 100 passes through the discontinuous portion 232 of the rib 230 of the needle hub 200. The needle hub 200 is rotated inside the cap 100 until the second protrusion 122 abuts against the stopper 234.

[0047] The sealing member 300 is attached to the barrel 400. Specifically, the nozzle portion 440 of the barrel 400 is fitted into the opening at the base end of the sealing member 300.

[0048] In this state, the cap 100 and the needle hub 200 are attached to the barrel 400. Specifically, the neck 420 is inserted into the cap 100 so that the first protrusion 162 of the cap 100 passes through the guide groove 439 of the neck 420. The first protrusion 162 rides over the inclined protrusion 438 provided in the guide groove 439, thereby preventing the cap 100 from coming off the barrel 400. This completes the attachment of the sealing member 300, rubber packing 190, needle hub 200, and cap 100 to the barrel 400.

[0049] Thereafter, the inside of barrel 400 is filled with the medicinal liquid and plunger 500 is attached. Before attaching sealing member 300 to barrel 400, barrel 400 may be filled with the medicinal liquid in advance, and the tip end of plunger 500 may be inserted into the rear end of barrel 400.

[0050] The operation when using the syringe 1 will be described. The hollow portion of the barrel 400 is pre-filled with the medicinal liquid, and the tip of the plunger 500 is inserted into the base end side of the barrel 400. Before administering the medicinal liquid to a patient, the cap 100 is rotated. By rotating the cap 100, the tip 214 at the base end of the double-ended needle 210 is pierced through the sealing member 300. This allows the interior of the double-ended needle 210 to communicate with the interior of the barrel 400. This operation will be described in more detail below.

[0051] 8 to 10 , with the sealing member 300, rubber gasket 190, needle hub 200, and cap 100 attached to the barrel 400, the first protrusion 162 of the cap 100 is positioned within the spiral groove 436 of the neck 420. When the cap 100 is rotated in the direction indicated by the arrow in FIGS. 7 and 8 in this state, the first protrusion 162 is guided by the spiral groove 436 and moves to the proximal end of the spiral groove 436. This causes the cap 100, as well as the needle hub 200 and rubber gasket 190 attached to the cap 100, to move proximally. At this time, the second protrusion 122 of the cap 100 is engaged with the rib 230 of the needle hub 200 ( FIGS. 9 and 10 ), so the rubber gasket 190 remains held between the cap 100 and the needle hub 200. This keeps the tip of the double-ended needle 210 isolated from the external space. The second protrusion 122 slides along the base end surface of the rib 230 as the cap 100 rotates. Because the third protrusion 228 and the guide protrusion 226 are located within the second linear groove 428 provided on the inner circumferential surface of the neck 420, the needle hub 200 does not rotate relative to the neck 420. The needle hub 200 moves axially relative to the neck 420.

[0052] Further rotation of the cap 100 results in the state shown in Figures 11 to 14. In this state, the tip 214 at the base end of the double-ended needle 210 penetrates the partition 330 of the sealing member 300. This allows communication between the hollow portion of the barrel 400 and the interior of the double-ended needle 210. At the same time, the third protrusion 228 of the needle hub 200 engages with the seventh engagement portion 432 of the neck portion 420. This prevents the needle hub 200 from moving in the distal direction, and the needle hub 200 is fixed to the barrel 400.

[0053] When the first protrusion 162 abuts against the abutment wall 434, further rotation of the cap 100 is prevented. At this time, the first protrusion 162 is positioned in front of the opening 430. At the same time, the second protrusion 122 of the cap 100 is positioned at the discontinuous portion 232 of the rib 230. When the user moves the cap 100 toward the distal end, the first protrusion 162 passes through the first linear groove 424 ( FIG. 14 ), and at the same time, the second protrusion 122 passes through the discontinuous portion 232 of the rib 230 ( FIG. 13 ), causing the cap 100 to detach from the neck portion 420. This allows the cap 100 to be removed from the barrel 400. When the cap 100 is removed from the barrel 400, the rubber gasket 190 is also removed along with the cap 100. Removing the cap 100 exposes the tip 212 on the distal end of the double-ended needle 210, allowing for administration of the medicinal liquid.

[0054] In the syringe 1 of this embodiment, by rotating the cap 100, the cap 100 is guided by the first protrusion 162 and the spiral groove 436 and moves toward the proximal end. Accordingly, the hub 220 also moves toward the proximal end. Because the cap 100 and the hub 220 move simultaneously, no gap is created between the cap 100 and the hub, as occurs in conventional syringes. This allows the double-ended needle 210 attached to the hub 220 to be isolated from the external space until the cap 100 is removed. As a result, the double-ended needle 210 can be prevented from being contaminated.

[0055] In syringe 1 of the present embodiment, the tip side of barrel 400 can be sealed with sealing member 300 until immediately before the medicinal liquid is administered, thereby preventing leakage of the medicinal liquid filled in barrel 400. When used as a prefilled syringe, leakage of the prefilled medicinal liquid is particularly problematic, but by using syringe 1 of the present embodiment as a prefilled syringe, leakage of the medicinal liquid can be prevented.

[0056] In the syringe of this embodiment, the needle hub 200 is moved toward the proximal end by rotating the cap 100. For example, compared to when the cap 100 is moved linearly toward the proximal end and the needle hub 200 is moved toward the proximal end in association with this, the needle hub 200 can be moved toward the proximal end more reliably with less force.

[0057] <Summary of Contents Disclosed in the Embodiments, etc.> The features disclosed in the above-described embodiments can be summarized as follows.

[0058] a syringe comprising: a barrel having a space for accommodating a medicinal solution, the barrel having a nozzle portion communicating with the space, and an annular neck portion surrounding the nozzle portion; a cap rotatably attached to the barrel about the central axis of the barrel as an axis of rotation, the cap having a first engaging portion on its inner surface; a double-ended needle extending parallel to the central axis of the barrel; a hub that holds the double-ended needle, the hub having at least a rear end thereof located inside the neck; and a sealing member that seals the nozzle portion of the barrel and is located toward the rear end of the double-ended needle, the neck having a second engaging portion on its outer peripheral surface that engages with the first engaging portion, one of the first engaging portion and the second engaging portion being a spiral groove and the other being a first protrusion located within the spiral groove; and by rotating the cap about the central axis of the barrel as an axis of rotation, the cap and the hub are guided by the first engaging portion and the second engaging portion and move in a direction toward the rear end of the barrel, and the rear end of the double-ended needle penetrates the sealing member.

[0059] [Supplementary Note 2] The syringe according to Supplementary Note 1, wherein the first engagement portion is the spiral groove and the second engagement portion is the first protrusion.

[0060] [Supplementary Note 3] The syringe according to Supplementary Note 1 or Supplementary Note 2, further comprising a first linear groove that is continuous with an end of the spiral groove and extends parallel to the central axis, and the first protrusion can pass through the first linear groove.

[0061] [Appendix 4] The syringe described in any one of Appendices 1 to 3, further comprising an annular gasket provided between the hub and the cap, wherein the hub has a third engagement portion protruding from its outer peripheral surface, and the cap has a fourth engagement portion protruding from its inner peripheral surface, and the third engagement portion and the fourth engagement portion engage with each other to tightly seal the gasket to the hub and the cap.

[0062] [Appendix 5] The syringe described in Appendix 4, wherein one of the third engagement portion and the fourth engagement portion is a rib extending in a circumferential direction, and the other is a second protrusion, the rib has a discontinuous portion where the rib is interrupted in the circumferential direction, and the second protrusion of the cap can pass through the discontinuous portion.

[0063] [Appendix 6] The syringe described in any one of Appendices 1 to 5, wherein the hub has a fifth engagement portion on its outer peripheral surface, the neck has a sixth engagement portion on its inner peripheral surface, one of the fifth engagement portion and the sixth engagement portion is a second linear groove extending parallel to the central axis, and the other is a third protrusion located within the second linear groove.

[0064] [Appendix 7] The syringe described in Appendix 6, wherein the second linear groove has a seventh engagement portion at its rear end with which the third protrusion can engage, and the hub is fixed to the neck portion by the third protrusion engaging with the seventh engagement portion.

[0065] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0066] 1 Syringe, 100 Cap, 110 Small diameter portion, 112 Hollow portion, 114 Small diameter portion base end surface, 122 Second protrusion (fourth engagement portion), 160 Large diameter portion, 162 First protrusion (first engagement portion), 168 Non-slip, 190 Gasket, 200 Needle hub, 210 Double-ended needle, 212, 214 Tip, 220 Hub, 222 Needle holding portion, 224 Hub body, 226 Guide protrusion, 228 Third protrusion (fifth engagement portion), 228a Tip portion, 230 Rib (third engagement portion), 232 Discontinuous portion, 234 Stopper, 300 Sealing member, 310 Annular rib, 330 Partition, 400 Barrel, 410 Barrel body, 412 Flange, 420 Neck portion, 424 First linear groove, 428: Second linear groove (sixth engagement portion), 430: Opening, 432: Seventh engagement portion, 434: Abutment wall, 436: Spiral groove (second engagement portion), 438: Slanted protrusion, 439: Guide groove, 440: Nozzle portion, 500: Plunger, 510: Gasket, 520: Plunger body, 522: Screw, 524: Reinforcing rib, 526: Base end rib.

Claims

a double-ended needle extending parallel to the central axis of the barrel; a hub that holds the double-ended needle and has at least a rear end located inside the neck; and a sealing member that seals the nozzle portion of the barrel and is located in the direction of the rear end of the double-ended needle, the neck having a second engaging portion on its outer surface that engages with the first engaging portion, one of the first engaging portion and the second engaging portion being a spiral groove and the other being a first protrusion located within the spiral groove, and by rotating the cap about the central axis of the barrel as an axis of rotation, the cap and the hub are guided by the first engaging portion and the second engaging portion to move in a direction toward the rear end of the barrel, and the rear end of the double-ended needle penetrates the sealing member.

2. The syringe according to claim 1, wherein said first engagement portion is said spiral groove and said second engagement portion is said first protrusion.

3. A syringe as described in claim 1 or claim 2, which has a first linear groove that is continuous with an end of the spiral groove and extends parallel to the central axis, and wherein the first protrusion can pass through the first linear groove.

4. A syringe as described in claim 1 or claim 2, further comprising an annular gasket provided between the hub and the cap, wherein the hub has a third engagement portion protruding from its outer peripheral surface, and the cap has a fourth engagement portion protruding from its inner peripheral surface, and the third engagement portion and the fourth engagement portion engage with each other to tightly seal the gasket against the hub and the cap.

5. A syringe as described in claim 4, wherein one of the third engagement portion and the fourth engagement portion is a rib extending in a circumferential direction and the other is a second protrusion, the rib has a discontinuous portion where the rib is interrupted in the circumferential direction, and the second protrusion of the cap can pass through the discontinuous portion.

6. A syringe as described in claim 1 or claim 2, wherein the hub has a fifth engagement portion on its outer circumferential surface, the neck portion has a sixth engagement portion on its inner circumferential surface, one of the fifth engagement portion and the sixth engagement portion being a second linear groove extending parallel to the central axis, and the other being a third protrusion located within the second linear groove.

7. The syringe according to claim 6, wherein the second linear groove has a seventh engagement portion at its rear end with which the third projection can engage, and the hub is fixed to the neck portion by the third projection engaging with the seventh engagement portion.

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