Syringe

Abstract

To provide a syringe capable of preventing leakage of a chemical liquid filled in a barrel.SOLUTION: A syringe 1 includes: a barrel 400; a cap 100 rotatably mounted on the barrel 400 with the central axis of the barrel 400 as the rotation axis, and having a spiral guide part 122 in the inner surface; a double-hook needle 210 extending in parallel to the central axis of the barrel 400; a hub 200 having an engagement part 226 for holding the double-hook needle 210 and engaged with the guide part 122, and mounted on the barrel 400 so as to be movable backward; and a sealing member for sealing the tip side of the barrel 400 and positioned at the rear end side of the double-hook needle 210. By the rotation of the cap 100, the engagement part 226 is guided by the guide part 122, the hub 200 moves to the rear end side, and the rear end of the double-hook needle 210 is penetrated into the sealing member 300.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] This disclosure relates to a syringe.

Background Art

[0002] For example, Japanese Patent No. 6074418 (Patent Document 1) discloses a syringe. The syringe includes a barrel, a hub attached to the tip of the barrel, and a syringe needle held by the hub. By attaching the hub holding the syringe needle to the tip of the barrel, the chemical solution filled in the barrel can be administered to a patient.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a conventional syringe, since the inside of the barrel and the inside of the syringe needle attached to the barrel are always in communication, there is a possibility that the chemical solution filled in the barrel may leak from the syringe needle. Particularly, when the syringe is used as a prefilled syringe in which the chemical solution is filled in the barrel in advance, it is necessary to prevent the chemical solution from leaking during storage or transportation of the prefilled syringe.

[0005] Therefore, this disclosure disclosure is made to solve the above problems, and an object of the present disclosure is to provide a syringe capable of preventing leakage of the chemical solution filled in the barrel.

Means for Solving the Problems

[0006] A syringe according to an embodiment based on this disclosure comprises a barrel having a space for containing a drug solution, a cap rotatably attached to the barrel with respect to the barrel's central axis and having a spiral guide on its inner surface, a double-ended needle extending parallel to the barrel's central axis, a hub retractably attached to the barrel and having an engaging portion that holds the double-ended needle and engages with the guide, and a sealing member that seals the tip of the barrel and is located at the rear end of the double-ended needle. By rotating the cap with respect to the barrel's central axis, the engaging portion is guided by the guide, the hub moves to the rear end, and the rear end of the double-ended needle penetrates the sealing member.

[0007] In the syringe described above, the guide portion of the cap includes a first guide portion and a second guide portion, the engaging portion of the hub includes a first engaging portion and a second engaging portion, the first guide portion and the second guide portion are symmetrical with respect to the central axis of the barrel, and the first engaging portion and the second engaging portion are symmetrical with respect to the central axis of the barrel.

[0008] In the syringe described above, the hub may have a stopper that engages with the barrel to prevent the hub from moving toward the tip when the rear end of the double-ended needle has passed through the sealing member.

[0009] In the syringe described above, the cap may have a projection protruding from its inner surface, and the barrel may have a rib protruding from its outer surface and extending in the circumferential direction, wherein the projection may abut against the rear end of the rib, thereby guiding the cap in a rotational direction with the central axis of the barrel as the axis of rotation.

[0010] In the syringe described above, the rib may have a discontinuous section in the circumferential direction of the barrel where the rib is interrupted, and the projection of the cap may be positioned at the discontinuous section so that the cap can be removed from the barrel. [Effects of the Invention]

[0011] The syringe described herein provides a syringe that can prevent leakage of the drug solution filled in the barrel. [Brief explanation of the drawing]

[0012] [Figure 1] This is an exploded perspective view of a syringe in an embodiment based on this disclosure. [Figure 2] This is a perspective view of the cap in an embodiment based on this disclosure. [Figure 3] This is a longitudinal cross-sectional view of the cap in an embodiment based on this disclosure. [Figure 4] This is a perspective view of the cap in an embodiment based on this disclosure, viewed from the base end. [Figure 5] This is a front view of a hub with a needle in an embodiment based on the present disclosure. [Figure 6] This is a perspective view of a barrel in an embodiment based on this disclosure. [Figure 7] This is a front view illustrating the operation of the syringe in an embodiment based on this disclosure. [Figure 8] This is a front view illustrating the operation of the syringe in an embodiment based on this disclosure. [Figure 9] This is a front view illustrating the operation of the syringe in an embodiment based on this disclosure. [Figure 10] This is a cross-sectional view illustrating the operation of a syringe in an embodiment based on this disclosure. [Figure 11] This is a cross-sectional view illustrating the operation of a syringe in an embodiment based on this disclosure. [Figure 12] This is a longitudinal cross-sectional view of a cap in a modified example of an embodiment based on this disclosure. [Figure 13] This is a perspective view of a barrel in a modified example of an embodiment based on this disclosure. [Modes for carrying out the invention]

[0013] Hereinafter, the syringe in the embodiment based on the present disclosure will be described with reference to the drawings. First, the structure of the syringe in the embodiment based on the present disclosure will be mainly described with reference to FIGS. 1 to 6.

[0014] FIG. 1 is an exploded perspective view of the syringe in the present embodiment. The syringe 1 according to the present embodiment includes a cap 100, a hub 200 with a needle, a sealing member 300, a barrel 400, and a plunger 500. In the following description, the tip side (the upper side in FIG. 1) of the cap 100 is referred to as the tip side, and the rear end side (the lower side in FIG. 1) of the plunger 500 is referred to as the base end side. Also, in the syringe 1, the axis extending through the center of the barrel 400 is referred to as the central axis, and the direction in which the central axis extends is referred to as the axial direction.

[0015] FIG. 2 is a perspective view of the cap in the present embodiment, FIG. 3 is a longitudinal sectional view of the cap in the present embodiment, and FIG. 4 is a perspective view of the cap in the present embodiment as viewed from the base end side.

[0016] The cap 100 includes a small-diameter portion 110 located at the tip of the cap 100, an intermediate-diameter portion 120 continuous with the base end side of the small-diameter portion 110, and a large-diameter portion 160 continuous with the base end side of the intermediate-diameter portion 120. The inner diameter of the intermediate-diameter portion 120 is larger than the inner diameter of the small-diameter portion 110, and the inner diameter of the large-diameter portion 160 is larger than the inner diameter of the intermediate-diameter portion 120. The shape of the cap 100 in the present embodiment is merely an example. For example, as in the cap 100A shown in FIG. 12, the inner diameters of the portions corresponding to the small-diameter portion 110 and the intermediate-diameter portion 120 in FIG. 3 may be made constant.

[0017] The small-diameter portion 110 is a cylindrical body with a closed tip. The small-diameter portion 110 covers the tip side of the double-headed needle 210 of the hub 200 with a needle in the state where the cap 100 is attached to the syringe 1. The small-diameter portion 110 has a hollow portion 112, and the tip side of the double-headed needle 210 is located in the hollow portion 112. A small-diameter portion base end surface 114 extending in the circumferential direction and having an annular shape is formed on the base end side of the small-diameter portion 110.

[0018] The inner surface of the intermediate diameter portion 120 of the cap 100 has a substantially cylindrical shape. A spiral guide portion 122 is provided on the inner surface of the intermediate diameter portion 120 of the cap 100. The guide portion 122 is a stepped portion that protrudes inward from the inner surface of the intermediate diameter portion 120 and extends spirally. As shown in particular in Figure 3, the guide portion 122 is displaced towards the base end as it moves circumferentially along the inner surface of the intermediate diameter portion 120.

[0019] An axial step portion 124 is continuous with the outermost tip of the guide portion 122. The axial step portion 124 is a step that protrudes inward from the inner surface of the intermediate diameter portion 120. The axial step portion 124 extends axially toward the base end. As shown in Figure 3, the tip side of the guide portion 122 and the tip side of the axial step portion 124 are continuous in directions that form an acute angle with each other.

[0020] The intermediate diameter portion 120 is provided with a circumferential step portion 126 that extends in the circumferential direction, continuous with the base end side of the guide portion 122 and the base end side of the axial step portion 124. The circumferential step portion 126 constitutes the base end side of the intermediate diameter portion 120. The circumferential step portion 126 is surrounded by the inner surface of the large diameter portion 160.

[0021] The outer circumferential surface of the large-diameter portion 160 is provided with anti-slip features 168 consisting of axially extending ribs. Multiple anti-slip features 168 are provided, arranged parallel to each other. The anti-slip features 168 function as a non-slip feature when the user grips and rotates the cap 100 with their fingers.

[0022] The large-diameter portion 160 is provided with a projection 162 that protrudes inward from the inner surface. The projection 162 has a wedge-shaped cross-section. The projection 162 has an inclined surface on the base end side. The inclined surface is inclined to move towards the center as it progresses from the base end side to the tip end side.

[0023] As shown in Figure 4, each of the guide portion 122 and projection 162 is provided in pairs. The guide portion 122 includes a first guide portion 1221 and a second guide portion 1222, and the first guide portion 1221 and the second guide portion 1222 are symmetric with respect to the central axis of the barrel 400. The projection 162 includes a first projection 1621 and a second projection 1622, and the first projection 1621 and the second projection 1622 are symmetric with respect to the central axis of the barrel 400.

[0024] Figure 5 is a front view of the needle-equipped hub in this embodiment. The needle-equipped 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 that extends in the axial direction. The tip end and base end of the double-ended needle 210 have sharply pointed tips 212 and 214, respectively.

[0025] The hub 220 is provided with a cylindrical hub body 224 and a needle-holding portion 222 that protrudes toward the tip from the tip side surface of the hub body 224. The needle-holding portion 222 has a smaller diameter than the hub body 224, and a double-ended needle 210 passes through its interior. The needle-holding portion 222 also extends toward the base end inside the hub body 224 (see Figures 10 and 11). The double-ended needle 210 is fixed to the hub body 224 by the needle-holding portion 222.

[0026] The hub body 224 has engaging portions 226 that protrude from its outer circumferential surface. The engaging portions 226 are provided on the outer circumferential surface near the tip of the hub body 224. A pair of engaging portions 226 are provided on the hub body 224. The pair of engaging portions 226 are symmetrical with respect to the central axis of the barrel 400. In a front view, the engaging portion 226 has the shape of a substantially right triangle. The engaging portion 226 has a slope 226a. The slope 226a is inclined in a direction tangent to the guide portion 122. In this embodiment, the syringe 1 has a pair of both the guide portion 122 and the engaging portions 226, but for example, it may have one guide portion 122 and one engaging portion 226, or four guide portions 122 and four engaging portions 226.

[0027] The hub body 224 has a stopper 228 that protrudes from its outer circumferential surface. The stopper 228 is provided on the outer circumferential surface near the base end of the hub body 224. A pair of stoppers 228 are provided on the hub body 224. The pair of stoppers 228 are symmetrical with respect to the central axis of the barrel 400. The engaging portion 226 and the stopper 228 are aligned in the direction of the central axis. The stopper 228 has a contact surface 228a and an inclined surface 228b. The inclined surface 228b is inclined to protrude outward as it approaches the tip. The contact surface 228a is continuous with the tip side of the inclined surface 228b. The contact surface 228a extends in a direction perpendicular to the axial direction.

[0028] A rubber packing 190 is provided between the hub body 224 and the circumferential stepped portion 126 of the cap 100 (see Figures 1, 10, and 11). The rubber packing 190 is an annular packing made of rubber. 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, thermoplastic elastomer may be used.

[0029] Figure 6 is a perspective view of the barrel in this embodiment. The barrel 400 has a barrel body 410 and a neck portion 420. The barrel body 410 is a hollow cylinder filled with a chemical 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.

[0030] The neck portion 420 is continuous with the tip side of the barrel body 410. As shown in Figure 6, the outer diameter of the neck portion 420 is smaller than the outer diameter of the barrel body 410. However, the outer diameter of the neck portion 420 may be the same as the outer diameter of the barrel body 410, or the outer diameter of the neck portion 420A may be larger than the outer diameter of the barrel body 410A, as shown in barrel 400A in Figure 13. As shown in Figure 1, an opening 430 is provided near the base end of the neck portion 420 (see Figures 1 and 7 to 9). The opening 430 is rectangular in front view. The tip edge of the opening 430 constitutes an engaged portion 432 into which the contact surface 228a of the stopper 228 of the hub 220 engages.

[0031] A guide groove 428 is provided on the inner surface of the neck portion 420, extending axially to connect the tip of the neck portion 420 to the opening 430. The guide groove 428 is continuous with the hub body 224 to guide the stopper 228 from the tip of the neck portion 420 to the opening 430.

[0032] The tip of the neck portion 420 is provided with a rib 422 that protrudes outward from the outer circumferential surface. The rib 422 extends circumferentially along the tip of the neck portion 420. The rib 422 has a discontinuous portion 424 in the circumferential direction where the rib 422 is interrupted. The neck portion 420 is provided with a guide rib 434 that extends axially along the discontinuous portion 424. The guide rib 434 is a linear projection that protrudes outward from the outer circumferential surface of the neck portion 420.

[0033] A recess 426 is provided on the outer circumferential surface of the rib 422. The recess 426 is a recess that extends from the tip of the neck portion 420 to the axial middle portion of the rib 422 (just before the base end of the rib 422). The base end side surface of the recess 426 is an inclined surface that is displaced outward as it progresses towards the base end.

[0034] A nozzle section 440 is provided inside the neck section 420 (see Figures 10 and 11). The nozzle section 440 has a flow path for the liquid chemical inside, and this flow path is in communication with the hollow section of the barrel body 410. The nozzle section 440 discharges the liquid chemical filled in the barrel 400 toward the tip. The nozzle section 440 is cylindrical in shape.

[0035] As shown in Figure 6, the projection 162 of the cap 100 is guided by the recess 426 and easily positioned on the proximal end side of the rib 422. Guided on the proximal end side of the rib 422, the projection 162 can move circumferentially along the proximal side surface of the rib 422. The guidance of the projection 162 by the rib 422 prevents the cap 100 from coming off towards the tip. As the projection 162 is guided along the rib 422, the cap 100 is guided in a direction that rotates around the central axis of the barrel 400.

[0036] When the cap 100 rotates and the projection 162 reaches the guide rib 434, further rotation of the cap 100 is prevented. At that time, the projection 162 is located at the discontinuity 424, and the cap 100 can be moved toward the tip by the projection 162 passing through the discontinuity 424. This allows the cap 100 to be removed from the barrel 400.

[0037] The hub body 224 and the sealing member 300 are arranged inside the neck portion 420 (see Figures 1, 10, and 11). The sealing member 300 is provided between the hub body 224 and the nozzle portion 440.

[0038] As shown in Figure 1, the sealing member 300 has a cylindrical shape. An annular rib 310 is provided on the tip side of the outer circumferential surface of the sealing member 300. The annular rib 310 is provided at two locations on the outer circumferential surface of the sealing member 300: at the tip and on the base side of the tip. 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 tip and base ends of the sealing member 300 are open. A partition 330 is provided in the middle of the sealing member 300 (see Figures 10 and 11). The partition 330 separates the opening on the tip end of the sealing member 300 from the opening on the base end of the sealing member 300. The nozzle portion 440 is fitted into the opening on the base end of the sealing member 300. The sealing member 300 is fitted inside the hub body 224. The sealing member 300 seals the tip end of the nozzle portion 440 until the double-ended needle 210 penetrates it. The material of the sealing member 300 is selected to be one that does not react with the liquid stored in the barrel 400. 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 of the plunger 500 is located in the hollow part of the barrel 400. As shown in Figure 1, the plunger 500 has a gasket 510 and a plunger body 520.

[0041] The gasket 510 is capable of sliding within the hollow portion of the barrel 400 while maintaining watertightness. The materials of the barrel 400 and the gasket 510 are selected so as not to react with the chemical solution stored in the barrel 400 and so as to allow the gasket 510 to slide within the barrel 400 in a liquid-tight manner. Examples of materials for the gasket 510 include thermoplastic elastomers and rubber.

[0042] A screw hole is provided at the base end of the gasket 510. The screw 522 at the tip of the plunger body 520 is screwed into the screw hole. This fixes the gasket 510 to the tip side of the plunger body 520. The gasket 510 and the plunger body 520 may be molded together as a single unit using synthetic resin or the like.

[0043] The plunger body 520 has a base 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 composed of four reinforcing ribs 524.

[0044] The operation of syringe 1 in this embodiment will be explained using Figures 7 to 11. Figures 7 to 9 are front views illustrating the operation of the syringe in this embodiment. Figures 10 and 11 are cross-sectional views illustrating the operation of the syringe in this embodiment.

[0045] First, the assembly procedure for syringe 1 of this embodiment will be described. In the following description, the case in which syringe 1 of this embodiment is used as a pre-filled syringe will be described, but syringe 1 according to this disclosure is not limited to being used as a pre-filled syringe.

[0046] A rubber packing 190 is pre-placed inside the cap 100. Next, the hub with needles 200 is inserted into the cap 100. At this time, the engaging portion 226 of the hub with needles 200 is guided by the guide portion 122 of the cap 100, and the engaging portion 226 is positioned at the acute angle formed by the guide portion 122 and the axial step portion 124 shown in Figure 7. The tip of the hub body 224 and the rubber packing 190 come into contact with each other.

[0047] The sealing member 300 is attached to the barrel 400. At this time, the inside of the barrel 400 is pre-filled with a chemical solution, and the tip of the plunger 500 is inserted into the rear end of the barrel 400. The nozzle portion 440 of the barrel 400 is fitted into the opening on the base end side of the sealing member 300.

[0048] In this state, the cap 100 and the needle-equipped hub 200 are attached to the barrel 400. Specifically, the cap 100 and the needle-equipped hub 200 are attached to the barrel 400 by inserting the projection 162 of the cap 100 into the recess 426 provided in the rib 422. By pressing the cap 100 toward the base end, the projection 162 inserted into the recess 426 overcomes the rib 422, and the cap 100 is mounted in the correct position. At this time, the tip side of the sealing member 300 is located inside the hub 220. The base end side of the hub 220 is located inside the neck portion 420. This completes the mounting of the sealing member 300, the needle-equipped hub 200, and the cap 100 to the barrel 400.

[0049] The operation of syringe 1 is described below. The hollow part of barrel 400 is pre-filled with the drug solution, and the tip of plunger 500 is inserted into the proximal end of barrel 400. Before administering the drug solution to the patient, rotate cap 100. Rotating cap 100 causes the tip 214 of the proximal end of double-ended needle 210 to pass through the sealing member 300. This creates communication between the inside of double-ended needle 210 and the inside of barrel 400. The following describes this operation in more detail.

[0050] As shown in Figures 7 and 10, with the sealing member 300, the needle hub 200, and the cap 100 mounted on the barrel 400, the engaging portion 226 of the needle hub 200 is in contact with the tip side of the guide portion 122. When the cap 100 is rotated in the direction indicated by the arrow in Figure 7 in this state, the engaging portion 226 is guided by the guide portion 122 and moves towards the base end, and at the same time the needle hub 200 moves towards the base end. At this time, the projection 162 of the cap 100 is in contact with the side surface of the rib 422 on the base end side, so the cap 100 is prevented from moving towards the tip and coming off the barrel 400.

[0051] By rotating the cap 100 further after passing through the state shown in Figure 8, the state shown in Figures 9 and 11 is reached. In this state, the tip 214 on the base end side of the double-ended needle 210 penetrates the partition 330 of the sealing member 300. This creates communication between the hollow part of the barrel 400 and the inside of the double-ended needle 210. At the same time, the stopper 228 of the needle-equipped hub 200 engages with the engaged portion 432 of the opening 430 of the neck portion 420. This prevents the needle-equipped hub 200 from moving toward the tip, and the needle-equipped hub 200 is fixed to the barrel 400. Since the base end side surface of the stopper 228 is an inclined surface 228b, it can move smoothly toward the base end inside the guide groove 428. Also, inside the neck portion 420, as the stopper 228 moves toward the base end inside the guide groove 428, the hub 220 moves toward the base end without rotating relative to the neck portion 420.

[0052] The cap 100 is prevented from rotating further when the projection 162 contacts the guide rib 434. At this time, the projection 162 is located at the discontinuity 424 of the rib 422. By moving the cap 100 toward the tip, the projection 162 passes through the discontinuity 424 and detaches from the neck portion 420. This allows the cap 100 to be removed from the barrel 400. With the cap 100 removed, the tip 212 of the double-ended needle 210 is exposed, and drug solution can be administered.

[0053] In the syringe 1 of this embodiment, the tip of the barrel 400 can be sealed with the sealing member 300 until just before administering the drug solution, thus preventing leakage of the drug solution filled in the barrel 400. When used as a pre-filled syringe, leakage of the pre-filled drug solution is a particular problem, but by using the syringe 1 of this embodiment as a pre-filled syringe, leakage of the drug solution can be prevented.

[0054] In the syringe of this embodiment, the needle-equipped hub 200 is moved toward the proximal end by rotating the cap 100. Compared to, for example, the case where the cap 100 is moved linearly toward the proximal end and the needle-equipped hub 200 is moved toward the proximal end as a result, the needle-equipped hub 200 can be reliably moved toward the proximal end with less force.

[0055] In the syringe 1 of this embodiment, the guide portion 122 of the cap 100 includes a first guide portion 1221 and a second guide portion 1222, and the engaging portion 226 of the hub 220 includes a first engaging portion and a second engaging portion. The first guide portion 1221 and the second guide portion 1222 are symmetric with respect to the central axis of the barrel 400, and the first engaging portion and the second engaging portion are symmetric with respect to the central axis of the barrel 400. Therefore, the hub 220 can be stably moved toward the base end while preventing the hub 220 from tilting relative to the barrel 400.

[0056] Furthermore, in the syringe 1 of this embodiment, the projection 162 abuts against the rear end of the rib 422, guiding the cap 100 in a rotational direction with the central axis of the barrel 400 as the axis of rotation. This ensures smooth rotation of the cap 100 and prevents the cap 100 from detaching from the barrel 400 during rotation.

[0057] The hub 220 has a stopper 228 that engages with the barrel 400 to prevent the hub 220 from moving toward the front end when the rear end tip 214 of the double-ended needle 210 has penetrated the sealing member 300, so that the hub body 224 and the double-ended needle 210 can be securely fixed to the barrel 400.

[0058] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended. [Explanation of symbols]

[0059] 1 Syringe, 100, 100A Cap, 110 Small diameter section, 112 Hollow section, 114 Small diameter section base end face, 120 Intermediate diameter section, 122 Guide section (1221 First guide section, 1222 Second guide section), 124 Axial step section, 126 Circumferential step section, 160 Large diameter section, 162 Projection (1621 First projection, 1622 Second projection), 168 Anti-slip, 190 Packing, 200 Hub with needle, 210 Double-ended needle, 212, 214 Tip, 220 Hub, 222 Needle holder section, 224 Hub body, 226 Engagement section, 226a Inclined surface, 228 Stopper, 228a Contact surface, 228b Inclined surface, 300 Sealing member, 310 Annular rib, 330 Partition, 400, 400A barrel, 410, 410A barrel body, 412 flange, 420, 420A neck, 422 rib, 424 discontinuity, 428 guide groove, 430 opening, 432 engaged part, 434 guide rib, 440 nozzle part, 500 plunger, 510 gasket, 520 plunger body, 522 screw, 524 reinforcing rib, 526 base end rib.

Claims

1. A barrel having a space for containing the chemical solution, A cap is rotatably mounted on the barrel with the barrel's central axis as the axis of rotation, and has a spiral guide 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, has an engaging portion that engages with the guide portion, and is retractably attached to the barrel, The barrel is sealed at the tip end and a sealing member is located at the rear end of the double-ended needle, By rotating the cap around the central axis of the barrel as the axis of rotation, the engaging portion is guided by the guide portion and the hub moves toward the rear end, and the rear end of the double-ended needle penetrates the sealing member. The aforementioned cap has a projection that protrudes from the inner circumferential surface, The barrel has ribs that protrude from the outer surface and extend in the circumferential direction, The projection abuts against the rear end of the rib, thereby guiding the cap in a rotational direction with the central axis of the barrel as the axis of rotation. The rib has a discontinuous portion where the rib is interrupted in the circumferential direction of the barrel. A syringe in which the projection of the cap is positioned at the discontinuous portion, thereby allowing the cap to be removed from the barrel.

2. The guide portion of the cap includes a first guide portion and a second guide portion. The engagement portion of the hub includes a first engagement portion and a second engagement portion. The syringe according to claim 1, wherein the first guide portion and the second guide portion are symmetrical with respect to the central axis of the barrel, and the first engaging portion and the second engaging portion are symmetrical with respect to the central axis of the barrel.

3. The syringe according to claim 1 or 2, wherein the hub has a stopper that engages with the barrel to prevent the hub from moving toward the tip when the rear end of the double-ended needle has passed through the sealing member.

Images