Syringe

Abstract

A syringe (1) comprises: a barrel (2); a plunger (3) comprising a first shaft portion (7) and a second shaft portion (8); and a biasing member (4), wherein the first shaft portion comprises a regulatory locking portion (76) and a depress locking portion (77), and the second shaft portion comprises a depress locked portion (84) and a regulatory portion (83), the regulatory portion being configured to be rotatable, about an origin end as the origin, between a regulatory retracted position at which a free end on the base-end side of the regulatory portion is located radially inward and a regulatory deployed position at which the free end is located radially outward. On the free end, there is provided a regulatory locked portion (82) that is locked against the regulatory locking portion by the biasing force of the biasing member at the regulatory deployed position. The syringe (1) comprises a regulatory release portion (5) to move the regulatory portion from the regulatory deployed position to the regulatory retracted position, and thus release the locking of the regulatory locked portion against the regulatory locking portion, at a position where the depressing for one administration of the syringe contents is completed.

Description

Syringe CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from Japanese Patent Application No. 2023-206990, the entire disclosure of which is incorporated herein by reference.

[0002] The present invention relates to a syringe capable of administering a medicinal liquid filled therein into the nostrils or oral cavity.

[0003] Conventionally, a syringe-type injector that divides and dispenses a liquid medicine or the like is known (see Patent Document 1). As shown in Fig. 33, a syringe-type injector 901 includes a syringe 902 and a plunger 903 inserted into the syringe 902. The plunger 903 has a first shaft member 903a and a second shaft member 903b held behind the first shaft member 903a.

[0004] The first shaft member 903a has a first elastic piece 931, a second elastic piece 932, and a third elastic piece 933, which are provided at different axial positions. The first elastic piece 931, the second elastic piece 932, and the third elastic piece 933 have the same shape and are elastically deformable radially inward or outward.

[0005] As shown in FIG. 34, the first elastic piece 931 extends from a base end 931 a toward a rear free end 931 b and has a locking protrusion 931 d that can be locked to the rear end of the syringe 902 .

[0006] The second elastic piece 932 is located further rearward than the first elastic piece 931. The second elastic piece 932 is also provided at a different circumferential position in the circumferential direction from the first elastic piece 931. The second elastic piece 932 extends from a base end 932a toward a rear free end 932b, and has a locking protrusion 932d that can be locked onto the rear end of the syringe 902.

[0007] The third elastic piece 933 is located further rearward than the second elastic piece 932. The third elastic piece 933 is also provided at the same circumferential position as the first elastic piece 931. The third elastic piece 933 extends from a base end 933a toward a rear free end 933b, and has a locking protrusion 933d that can be locked onto the rear end of the syringe 902.

[0008] The second shaft member 903b is held on the rear side of the first shaft member 903a. The second shaft member 903b also includes a pressing shaft 941 disposed inside the cylindrical portion 936 and a pressing flange 942 provided on the rear portion of the pressing shaft 941.

[0009] 35 and 37 , the pressing shaft 941 has a first support portion 945a that supports the free end portion 931b from the radially inner side when the first elastic piece 931 enters the syringe 902, thereby locking the locking protrusion 931d with the rear end of the syringe 902. The pressing shaft 941 also has a second support portion 945b that supports the free end portion 932b from the radially inner side when the second elastic piece 932 enters the syringe 902. The pressing shaft 941 also has a third support portion 945c that supports the free end portion 933b from the radially inner side when the third elastic piece 933 enters the syringe 902.

[0010] Furthermore, the pressing shaft 941 has, at its tip, a first pressing portion 946a that can axially press the free end portion 931b of the first elastic piece 931, whose engagement with the rear end of the syringe 902 by the engagement protrusion 931d has been released by the restoring force of the first elastic piece 931. Similarly, the pressing shaft 941 has a second pressing portion 946b that can axially press the free end portion 932b of the second elastic piece 932, and a third pressing portion 946c that can axially press the free end portion 933b of the third elastic piece 933. The first pressing portion 946a is provided at the tip of the pressing shaft 941.

[0011] The following describes how to use the syringe-type injector 901. This syringe-type injector 901 is capable of discharging the contents in the storage space in small amounts by gradually depressing the plunger 903.

[0012] First, when the plunger 903 is pushed in from the initial state shown in Fig. 33 , the first elastic piece 931 enters the syringe 902. At this time, a radially inward force is applied to the first elastic piece 931, and the free end 931b of the first elastic piece 931 is supported by the first support portion 945a, so that the region of the first elastic piece 931 between the base end 931a and the free end 931b elastically bends and deforms radially inward. Furthermore, as shown in Fig. 34 , the locking protrusion 931d of the first elastic piece 931 supported by the first support portion 945a locks with the rear end of the syringe 902, thereby stopping the pushing of the plunger 903 and ending the first discharge.

[0013] After the locking protrusion 931d is locked to the rear end of the syringe 902, when the forward pressing force of the pressing flange 942 is released, the second shaft member 903b is pushed rearward and moved by the restoring force of the first elastic piece 931. As the second shaft member 903b moves rearward, the first support portion 945a moves rearward beyond the free end portion 931b of the first elastic piece 931. Therefore, as shown in FIG. 35 , the free end portion 931b of the first elastic piece 931 moves radially inward, and the locking protrusion 931d is released from the rear end of the syringe 902.

[0014] Next, when the plunger 903 is pushed in from the state shown in Fig. 35, the second elastic piece 932 enters the syringe 902 while undergoing elastic deformation. Furthermore, the locking protrusion 932d of the second elastic piece 932 supported by the second support portion 945b is locked onto the rear end of the syringe 902, thereby stopping the entry of the plunger 903 and ending the second ejection. When the pressing force on the plunger 903 is released in this state, the restoring force of the second elastic piece 932 pushes and moves the second shaft member 903b rearward, resulting in the state shown in Fig. 37, making the third ejection possible.

[0015] Next, when the plunger 903 is pushed in from the state shown in Fig. 37, the third elastic piece 933 enters the syringe 902 while undergoing elastic deformation, as shown in Fig. 37. The locking protrusion 933d supported by the third support portion 945c locks onto the rear end of the syringe 902, stopping the entry of the plunger 903 and ending the third ejection. When the pressing force on the plunger 903 is released in this state, the restoring force of the third elastic piece 933 pushes and moves the second shaft member 903b rearward, resulting in the state shown in Fig. 39, making the fourth ejection possible.

[0016] Finally, the fourth ejection is performed by pushing the plunger 903 into the syringe 902 from the state shown in Fig. 39 to the state shown in Fig. 40. In this way, the syringe-type injector 901 can eject the contents of the syringe 902 in four separate ejections.

[0017] Japanese Patent Application Publication No. 2018-108146

[0018] However, in the syringe-type injector 901, the elastic forces of the first, second, and third elastic pieces 931, 932, and 933 are not sufficient to move the first, second, and third support portions 945a, 945b, and 945c completely backward, and the first, second, and third pressing portions 946a, 946b, and 946c may not reach the position where they press the free end portions, which may prevent the next ejection.

[0019] An object of the present invention is to provide a syringe that can reliably perform multiple ejections.

[0020] The syringe of the present invention is a syringe for administering contents in portions, and comprises: a barrel having a tip end for discharging the contents and a base end located on the axial opposite side of the tip end; a plunger that can be pushed into the barrel from the base end toward the tip end, the plunger comprising a first shank and a second shank that is inserted into the first shank and is movable in the axial direction relative to the first shank; and a biasing member that biases the second shank toward the base end side relative to the first shank, the first shank having a restricting locking portion that restricts movement of the second shank relative to the first shank due to the biasing force of the biasing member, the restricting locking portion being a plurality of restricting locking portions that are provided at intervals in the axial direction; and a push-in locking portion with which the second shaft locks when the second shaft is pushed inward, the second shaft comprising a push-in locked portion that locks with the push-in locking portion when the second shaft is pushed inward, and a restricting portion, the restricting portion being configured to be rotatable around the starting end between a restricted retracted position where a free end on the base end side of the restricting portion is positioned radially inward, and a restricted expanded position where the free end is positioned radially outward, the free end comprising a restricted locked portion that locks with the restricted locking portion by the biasing force of the biasing member at the restricted expanded position, and a restricting release portion that moves the restricting portion from the restricted expanded position to the restricted retracted position at a position where the pushing for administering the one dose of content is completed, thereby releasing the lock of the restricted locked portion with the restricting locking portion.

[0021] In addition, in the syringe, the regulating portion may be moved to the regulating retracted position by the regulating release portion, and then moved to the regulating deployed position between one of the plurality of regulating engagement portions that has been engaged for administering the one dose of contents and a regulating engagement portion adjacent to the regulating engagement portion that has been engaged for administering the one dose of contents on the base end side in the axial direction.

[0022] Moreover, in the syringe, the first shank includes a first main shank extending along the axial direction, the push-in locking portion includes a plurality of main shaft push-in locking portions provided on the first main shaft with axial spacing, the second shank includes a second main shaft extending along the axial direction and a push-in portion provided on the second main shaft, the push-in portion including a push-in portion configured to be rotatable around a starting end on the base end side of the push-in portion between a push-in retracted position where a free end on the tip side of the push-in portion is located radially inward and a push-in deployed position where the free end is located radially outward, and the push-in locked portion may include a main shaft push-in locked portion provided at the free end of the push-in portion, which locks with the main shaft push-in locked portion at the push-in deployed position during the pushing operation.

[0023] The syringe may also include a push-in guide portion between two axially adjacent spindle push-in locking portions that guides the push-in portion from the push-in deployment position to the push-in retract position, and the push-in guide portion may hold the push-in portion in the push-in retract position when the push-in portion moves axially from the spindle push-in locking portion on the tip side to the spindle push-in locking portion on the base side, and may release the hold of the push-in portion when the push-in portion is positioned on the base side relative to the base side spindle push-in locking portion.

[0024] FIG. 1A is a perspective view of a syringe according to this embodiment in an initial state. FIG. 1B is a left side view of the main parts of the syringe in the initial state. FIG. 1C is a cross-sectional view taken along line IC-IC in FIG. 1B. FIG. 2A is an exploded perspective view of the syringe. FIG. 2B is a front view of a second shaft portion of a plunger of the syringe. FIG. 2C is a perspective view of the second shaft portion as viewed from the left. FIG. 2D is a perspective view of the second shaft portion as viewed from the right. FIG. 2E is a perspective view of a first shaft portion of the plunger as viewed from the left. FIG. 2F is a perspective view of the first shaft portion as viewed from the right. FIG. 3A is a left side view of the main parts of the syringe during the first ejection. FIG. 3B is a cross-sectional view taken along line IIIB-IIIB in FIG. 3A. FIG. 3C is a cross-sectional view taken along line IIIC-IIIC in FIG. 3A. FIG. 4A is a left side view of the main parts of the syringe immediately before the second ejection. FIG. 4B is a cross-sectional view of the main parts taken along line IVB-IVB in FIG. 4A. FIG. 5A is a left side view of the essential parts of the syringe at the time of the second discharge. FIG. 5B is a cross-sectional view taken along line VB-VB in FIG. 5A. FIG. 5C is a cross-sectional view taken along line VC-VC in FIG. 5A. FIG. 6A is a left side view of the essential parts of the syringe immediately before the third discharge. FIG. 6B is a cross-sectional view taken along line VIB-VIB in FIG. 6A. FIG. 7A is a left side view of the essential parts of the syringe at the time of the third discharge. FIG. 7B is a cross-sectional view taken along line VIIB-VIIB in FIG. 7A. FIG. 7C is a cross-sectional view taken along line VIIC-VIIC in FIG. 7A. FIG. 8A is a left side view of the essential parts of the syringe immediately before the fourth discharge. FIG. 8B is a cross-sectional view taken along line VIIIB-VIIIB in FIG. 8A. FIG. 9A is a left side view of the essential parts of the syringe at the time of the fourth discharge. FIG. 9B is a cross-sectional view taken along line IXB-IXB in FIG. 9A. Fig. 10 is a perspective view of a syringe according to a modified example in an initial state. Fig. 11A is an exploded perspective view of the syringe. Fig. 11B is a perspective view of the second shaft of the plunger of the syringe as viewed from the right side. Fig. 11C is a perspective view of the first shaft of the plunger as viewed from the right side. Fig. 12A is a left side view of the main parts of the syringe in an initial state. Fig. 12B is a cross-sectional view of the main parts taken along line XIIB-XIIB in Fig. 12A. Fig. 13A is a left side view of the main parts of the syringe during the first ejection.FIG. 13B is a cross-sectional view of the essential parts taken along line XIIIB-XIIIB in FIG. 13A. FIG. 13C is a cross-sectional view of the essential parts taken along line XIIIC-XIIIC in FIG. 13A. FIG. 14A is a left side view of the essential parts of the syringe immediately before the second discharge. FIG. 14B is a cross-sectional view of the essential parts taken along line XIVB-XIVB in FIG. 14A. FIG. 15A is a left side view of the essential parts of the syringe during the second discharge. FIG. 15B is a cross-sectional view of the essential parts taken along line XVB-XVB in FIG. 15A. FIG. 16 is a perspective view of a syringe according to another modified example in an initial state. FIG. 17A is an exploded perspective view of the syringe. FIG. 17B is a perspective view of the second shaft of the plunger of the syringe as viewed from the right side. FIG. 17C is a perspective view of the first shaft of the plunger as viewed from the right side. Fig. 18A is a left side view of the main parts of the syringe in an initial state. Fig. 18B is a cross-sectional view of the main parts taken along line XVIIIB-XVIIIB in Fig. 18A. Fig. 18C is a cross-sectional view of the main parts taken along line XVIIIC-XVIIIC in Fig. 18A. Fig. 19A is a left side view of the main parts of the syringe at the time of the first discharge. Fig. 19B is a cross-sectional view of the main parts taken along line XIXB-XIXB in Fig. 19A. Fig. 19C is a cross-sectional view of the main parts taken along line XIXC-XIXC in Fig. 19A. Fig. 20A is a left side view of the main parts of the syringe immediately before the second discharge. Fig. 20B is a cross-sectional view of the main parts taken along line XXB-XXB in Fig. 20A. Fig. 20C is a cross-sectional view of the main parts taken along line XXC-XXC in Fig. 20A. Fig. 21A is a left side view of the main parts of the syringe at the time of the second discharge. FIG. 21B is a cross-sectional view of the essential parts taken along line XXIB-XXIB of FIG. 21A. FIG. 21C is a cross-sectional view of the essential parts taken along line XXIC-XXIC of FIG. 21A. FIG. 22A is a left side view of the essential parts immediately before the third discharge of the syringe. FIG. 22B is a cross-sectional view of the essential parts taken along line XXIIB-XXIIB of FIG. 22A. FIG. 22C is a cross-sectional view of the essential parts taken along line XXIIC-XXIIC of FIG. 22A. FIG. 23A is a left side view of the essential parts at the time of the third discharge of the syringe. FIG. 23B is a cross-sectional view of the essential parts taken along line XXIIIB-XXIIIB of FIG. 23A. FIG. 23C is a cross-sectional view of the essential parts taken along line XXIIIC-XXIIIC of FIG. 23A. FIG. 24 is a perspective view of a syringe according to another modified example in an initial state.FIG. 25A is an exploded perspective view of the syringe. FIG. 25B is a front view of the second shaft of the plunger of the syringe. FIG. 25C is a perspective view of the second shaft as viewed from the left side. FIG. 25D is a perspective view of the first shaft of the plunger as viewed from the left side. FIG. 26A is a left side view of the main parts of the syringe in an initial state. FIG. 26B is a cross-sectional view of the main parts taken along line XXVIB-XXVIB of FIG. 26A. FIG. 27A is a left side view of the main parts at the time of the first ejection of the syringe. FIG. 27B is a cross-sectional view of the main parts taken along line XXVIIB-XXVIIB of FIG. 27A. FIG. 27C is a cross-sectional view of the main parts taken along line XXVIIC-XXVIIC of FIG. 27A. FIG. 28A is a left side view of the main parts of the syringe immediately before the second ejection. FIG. 28B is a cross-sectional view of the main parts taken along line XXVIIIB-XXVIIIB of FIG. 28A. 29A is a left side view of the essential parts of the syringe during the second discharge. FIG. 29B is a cross-sectional view of the essential parts taken along line XXIXB-XXIXB in FIG. 29A. FIG. 30 is a cross-sectional view of the essential parts of a syringe according to another modified example in an initial state. FIG. 31 is an exploded perspective view of the syringe. FIG. 32 is a front view of a second shaft portion of the plunger of the syringe. A cross-sectional view of a conventional syringe-type injector in an initial state. A diagram illustrating the first discharge of the conventional syringe-type injector. A diagram illustrating a state in which the conventional syringe-type injector has completed the first discharge and the pressing force has been relaxed. A diagram illustrating a second discharge of the conventional syringe-type injector. A diagram illustrating a state in which the conventional syringe-type injector has completed the second discharge and the pressing force has been relaxed. A diagram illustrating a third discharge of the conventional syringe-type injector. A diagram illustrating a state in which the conventional syringe-type injector has completed the third discharge and the pressing force has been relaxed. A diagram illustrating a fourth discharge of the conventional syringe-type injector.

[0025] Hereinafter, a container according to an embodiment of the present invention will be described with reference to FIGS. 1A to 9B.

[0026] As shown in FIG. 1A , syringe 1 is a syringe for administering divided doses of its contents. Specifically, syringe 1 is a nasal administration container that can administer divided doses of mist-like liquid medicine into both nostrils. This syringe 1 administers the liquid medicine in four divided doses, but the liquid medicine may also be administered in two, three, or more divided doses. The liquid medicine is liquid, such as an influenza vaccine. Syringe 1 is approximately cylindrical in shape.

[0027] 1A and 2A , the syringe 1 includes a barrel 2 having a tip end 20 that ejects the content and a base end 21 that is located on the axially opposite side of the tip end 20. The syringe 1 also includes a plunger 3 and a biasing member 4. The syringe 1 also includes a restriction release portion 5. The syringe 1 also includes a pushing guide portion 6. The syringe 1 also includes a discharge nozzle 9.

[0028] In the syringe 1, the side where the tip portion 20 of the barrel 2 is disposed (the lower side in FIG. 1A ) is the "tip side," and the side where the base end portion 21 of the barrel 2 is disposed (the upper side in FIG. 1A ) is the "base side." Furthermore, the "axial direction" of the syringe 1 is the cylindrical axis direction of the syringe 1. Furthermore, the radial direction of the syringe 1 is also simply referred to as the "radial direction."

[0029] When using the syringe 1, from the initial state (FIGS. 1A to 1C), the plunger 3 is pushed toward the distal end to eject the first liquid medicine (FIGS. 3A to 3C). Next, after passing through a state immediately before the second liquid medicine ejection (FIGS. 4A and 4B), the plunger 3 is pushed toward the distal end to eject the second liquid medicine (FIGS. 5A to 5C). After passing through a state immediately before the third liquid medicine ejection (FIGS. 6A and 6B), the plunger 3 is pushed toward the distal end to eject the third liquid medicine (FIGS. 7A to 7C). Furthermore, after passing through a state immediately before the fourth liquid medicine ejection (FIGS. 8A and 8B), the plunger 3 is pushed toward the distal end to eject the fourth liquid medicine (FIGS. 9A and 9B).

[0030] Each component of the syringe 1 will be described in detail below.

[0031] The barrel 2 is a member that contains a medicinal liquid inside (see FIG. 1A ). In the syringe 1 of this embodiment, the barrel 2 includes a barrel body 22 and a finger grip 23 provided on the barrel body 22.

[0032] The barrel body 22 is a cylindrical body that accommodates the medicinal solution. In this barrel 2, a body distal end portion 220, which is the distal end of the barrel body 22, constitutes the distal end portion 20 of the barrel 2, and a body proximal end portion 221, which is the proximal end portion of the barrel body 22, constitutes the proximal end portion 21 of the barrel 2 (see FIG. 2A ). In addition to the body distal end portion 220 and the body proximal end portion 221, the barrel body 22 includes a cylindrical body connecting portion 222 that connects the body distal end portion 220 and the body proximal end portion 221. The barrel body 22 also includes a flange portion 223 that extends outward (in the radially outward direction of the barrel body 22) from the entire outer periphery of one end of the body proximal end portion 221 in the cylindrical axis direction.

[0033] The outer diameter of the main body tip portion 220 is smaller than the outer diameter of the main body connecting portion 222. The outer diameter of the main body connecting portion 222 is substantially the same at any position in the axial direction of the cylinder. The flange portion 223 is annular (e.g., circular) when viewed in the axial direction of the cylinder.

[0034] The barrel body 22 is formed of, for example, a transparent material that can withstand the internal pressure applied when administering the medicinal solution. Specifically, the material of the barrel body 22 is glass, a resin containing a cyclic olefin such as norbornene as a repeating unit, etc. More specifically, the material of the barrel 2 is glass, a transparent resin such as COP (cycloolefin polymer), which is a homopolymer of a cyclic olefin, or COC (cycloolefin copolymer), which is a copolymer of a cyclic olefin and ethylene, etc.

[0035] The finger grip 23 is a portion on which the user places their fingers when using the syringe 1. It is fitted onto the body base end 221 and flange portion 223 of the barrel body 22. In this embodiment, the finger grip 23 includes a grip body portion 230 that covers the flange portion 223, and a pair of grip extension portions 231 that extend radially outward from two opposing positions on the grip body portion 230.

[0036] The grip main body 230 is formed in an annular shape so as to surround the plunger 3. In the present embodiment, the grip main body 230 includes a main body base end portion 232 that overlaps the base end side of the flange portion 223 of the barrel body 22, and a main body tip portion 233 that overlaps the tip side of the flange portion 223.

[0037] The finger grip 23 includes an ejection completion locking portion 24 that locks with the plunger 3 when the first, second, and third ejections of the syringe 1 are completed. In this embodiment, the surface of the finger grip 23 facing the base end, specifically, the base end surface 2320 that faces the base end of the main body base end portion 232, constitutes the ejection completion locking portion 24. A pair of ejection completion locking portions 24 are provided at positions facing each other across the central axis of the finger grip 23. Specifically, the ejection completion locking portions 24 face each other at positions 180° apart in the circumferential direction of the finger grip 23.

[0038] The plunger 3 is a member that can be pushed into the barrel 2 from the base end 21 toward the tip end 20. The plunger 3 also includes a first shaft portion 7 and a second shaft portion 8 that is inserted into the first shaft portion 7 and is movable in the axial direction relative to the first shaft portion 7. In this embodiment, the plunger 3 is provided with a piston 30. In this plunger 3, a biasing member 4 is provided at the tip end of the second shaft portion 8, and the piston 30 is provided at the tip end of the first shaft portion 7. The plunger 3 is inserted into the barrel 2 with the biasing member 4 located on the base end side and the piston 30 located on the tip end side.

[0039] The first shaft portion 7 is a shaft body that moves together with the second shaft portion 8 when the liquid medicine is discharged (see FIG. 1A). The first shaft portion 7 is a member that surrounds the second shaft portion 8. As shown in FIGS. 2E and 2F, the first shaft portion 7 has a tubular shape, specifically, a substantially cylindrical shape. The first shaft portion 7 also has an axially asymmetric shape. The first shaft portion 7 is made of a resin such as POM (polyacetal).

[0040] In this embodiment, the first shank 7 includes a first main shaft portion 70 extending along the axial direction, a first base end portion 71 provided at the base end of the first main shaft portion 70, and a first tip end portion 72 provided at the tip end of the first main shaft portion 70 (see FIG. 2A ). The first shank 7 also includes a plurality of one-side convex portions 73 provided on one side of the first main shaft portion 70 at one position in the circumferential direction, and a plurality of other-side convex portions 74 provided on the other side of the first main shaft portion 70 at another position in the circumferential direction (see FIGS. 2E and 2F ). The first main shaft portion 70 is integrally molded with the first base end portion 71, the first tip end portion 72, and the convex portions 73 and 74. The first main shaft portion 70 may be separate from at least one of the first base end portion 71, the first tip end portion 72, and the convex portions 73 and 74, or may be formed by combining separate members.

[0041] The first main shaft portion 70 is a portion that surrounds the second shaft portion 8. In this embodiment, the first main shaft portion 70 is substantially cylindrical with a uniform diameter at any portion in the axial direction. A one-side slit 700 is formed on one side of the first main shaft portion 70, and a other-side slit 701 is formed on the other side of the first main shaft portion 70. The slits 700, 701 are spaced apart in the circumferential direction, and in this embodiment, are located at positions that face each other across the central axis of the first main shaft portion 70. Specifically, the slits 700, 701 face each other at positions that are 180° apart in the circumferential direction of the first main shaft portion 70.

[0042] Furthermore, at positions circumferentially adjacent to slits 700, 701 of first main shaft portion 70, irregularities are formed on the outer peripheral surface to accumulate pressure when the chemical solution is discharged, i.e., to provide a force for spraying the chemical solution. In this embodiment, first main shaft portion 70 is formed with a plurality of ridges that each extend in the circumferential direction and are aligned in the axial direction. Note that first main shaft portion 70 does not necessarily have to be provided with such irregularities.

[0043] The slits 700 and 701 each extend linearly along the axial direction. As shown in Fig. 3B, a portion of the second shaft portion 8 protrudes radially outward from the first main shaft portion 70 via the slits 700 and 701.

[0044] The first main shaft portion 70 is provided with five pairs of one-side protrusions 73 spaced apart in the axial direction and sandwiching the one-side slit 700 (see FIG. 2E ). Also, each pair of protrusions 731, 732, 733, 734, and 735 is provided with one pair sandwiching the one-side slit 700. The one-side protrusions 73 guide the portion of the second shaft portion 8 that protrudes radially outward from the one-side slit 700. Furthermore, the pair of one-side protrusions 73 sandwiching the one-side slit 700 protrudes from the first main shaft portion 70 in the circumferential direction by the same distance.

[0045] The detailed configuration of each one-side convex portion 73 will be described below. Each one-side convex portion 73 guides the axial movement of the second shaft portion 8 relative to the first shaft portion 7 when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4. Furthermore, each one-side convex portion 73 restricts the circumferential movement of the second shaft portion 8 while the movement of the second shaft portion 8 relative to the first shaft portion 7 is restricted by the biasing force of the biasing member 4. Specifically, each of the convex portions 731, 732, 733, 734, and 735 has guide surfaces 7310, 7320, 7330, 7340, and 7350 facing the one-side slit 700, which contact a portion of the second shaft portion 8, thereby guiding the axial movement of the second shaft portion 8 and restricting the circumferential movement of the second shaft portion 8. The guide surfaces 7310, 7320, 7330, 7340, and 7350 of the convex portion 73 are flat surfaces.

[0046] In this embodiment, the protruding portion 731 located at the most proximal end side and the protruding portion 735 located at the most distal end side have a larger axial dimension than the protruding portions 732, 733, and 734 located between them.

[0047] The protrusions 731, 732, 733, and 734 of the one-side protrusion 73, excluding the protrusion 735 located at the most distal end in the axial direction, include a restricting locking portion 76 that restricts movement of the second shaft portion 8 relative to the first shaft portion 7 due to the biasing force of the biasing member 4. In this embodiment, the distal end of each of the protrusions 731, 732, 733, and 734 constitutes the restricting locking portion 76. Furthermore, distal end surfaces 7311, 7321, 7331, and 7341, which are surfaces facing the distal ends of the protrusions 731, 732, 733, and 734, constitute a distal end surface 760 of the restricting locking portion 76. The distal end surface 760 of the restricting locking portion 76 abuts a portion of the second shaft portion 8, thereby restricting movement of the second shaft portion 8 relative to the first shaft portion 7 due to the biasing force. The distal end surface 760 of the restricting locking portion 76 is a flat surface.

[0048] A plurality of restricting locking portions 76 are provided at intervals in the axial direction, and in this embodiment, four sets are provided. Specifically, the restricting locking portions 76 include a plurality of spindle restricting locking portions 76 provided on the first spindle portion 70 at intervals in the axial direction, and in this embodiment, the restricting locking portions 76 are configured by four sets of spindle restricting locking portions 76 lined up in the axial direction.

[0049] Furthermore, four pairs of other-side protrusions 74 are provided on the first main shaft portion 70 at intervals in the axial direction, sandwiching the other-side slit 701 (see FIG. 2F ). Specifically, protrusions 741, 742, 743, and 744 are provided in pairs, each sandwiching the other-side slit 701. The other-side protrusions 74 guide the portion of the second shaft portion 8 that protrudes radially outward from the other-side slit 701. Furthermore, the pair of other-side protrusions 74 that sandwich the other-side slit 701 protrude from the first main shaft portion 70 in the circumferential direction by the same distance.

[0050] The detailed configuration of each other-side convex portion 74 will be described below. Each other-side convex portion 74 guides the axial movement of the second shaft portion 8 relative to the first shaft portion 7 when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4. Furthermore, the other-side convex portion 74 restricts the circumferential movement of the second shaft portion 8 while the movement of the second shaft portion 8 relative to the first shaft portion 7 is restricted by the biasing force of the biasing member 4. Specifically, the convex portions 741, 742, 743, and 744 have guide surfaces 7410, 7420, 7430, and 7440 facing the other-side slit 701 that abut against a portion of the second shaft portion 8, thereby guiding the axial movement of the second shaft portion 8 and restricting the circumferential movement of the second shaft portion 8. The guide surfaces 7410, 7420, 7430, and 7440 of the convex portions 74 are flat surfaces.

[0051] The other-side protrusions 74, except for the protrusion 744 located at the most distal end, include a push-in locking portion 77 that locks with the second shank 8 when the plunger 3 is pushed into the barrel 2. In this embodiment, the proximal end of each of the protrusions 741, 742, and 743 constitutes the push-in locking portion 77. The proximal end surfaces 7411, 7421, and 7431 of the protrusions 741, 742, and 743, which face the proximal end, constitute a proximal end surface 770 of the push-in locking portion 77. The proximal end surface 770 of the push-in locking portion 77 abuts a portion of the second shank 8, thereby restricting axial movement of the second shank 8 toward the distal end relative to the first shank 7 and enabling the plunger 3 to be pushed into the barrel 2. The proximal end surface 770 of the push-in locking portion 77 is a flat surface.

[0052] In this embodiment, the protruding portion 741 located at the most proximal end side and the protruding portion 744 located at the most distal end side have a larger axial dimension than the protruding portions 742 and 743 located between them.

[0053] The push-in locking portions 77 are provided in a plurality at intervals in the axial direction, and in this embodiment, three sets are provided. The push-in locking portions 77 also include a plurality of main shaft push-in locking portions 77 provided on the first main shaft portion 70 at intervals in the axial direction, and in this embodiment, the push-in locking portions 77 are configured by three sets of main shaft push-in locking portions 77 lined up in the axial direction.

[0054] In this embodiment, the protrusions 741, 742, and 743 comprise a push-in guide portion 6 that guides a portion of the second shaft portion 8 from a push-in deployed position to a push-in retracted position between two axially adjacent main shaft push-in locking portions 77. The tip end portions of the protrusions 741, 742, and 743 respectively constitute the push-in guide portion 6. Tip surfaces 7412, 7422, and 7432, which are surfaces facing the tip ends of the protrusions 741, 742, and 743, constitute tip surfaces 600 of the push-in guide portion 6.

[0055] The pushing guide portion 6 guides a portion of the second shaft portion 8 from the pushing-in deployed position to the pushing-in retracted position by having this tip surface 600 come into contact with a portion of the second shaft portion 8. Furthermore, the pushing guide portion 6 holds the pushing portion 85 in the pushing-in retracted position when the pushing portion 85 moves axially from the tip-side spindle pushing-in locking portion 77 to the base-side spindle pushing-in locking portion 77 of the two spindle pushing-in locking portions 77. Furthermore, when the pushing portion 85 is positioned on the base-end side relative to the base-end side spindle pushing-in locking portion 77, the pushing guide portion 6 releases the holding and allows the pushing portion 85 to move to the pushing-in deployed position.

[0056] The push-in guide parts 6 are provided in a plurality at intervals in the axial direction, and in this embodiment, three sets are provided. In this embodiment, the push-in guide parts 6 include a plurality of spindle push-in guide parts 6 provided on the first spindle part 70 at intervals in the axial direction, and in this embodiment, the push-in guide parts 6 are configured by three sets of spindle push-in guide parts 6 lined up in the axial direction.

[0057] First base end 71 is a portion that overlaps with second base end 81 of second shank 8. In this embodiment, first base end 71 extends radially outward from the entire outer periphery of the base end of first main shaft 70. First base end 71 has an annular (e.g., circular) shape when viewed axially. In this syringe 1, first base end 71 forms a push-in locking portion 77 that locks onto a portion of second base end 81 during the first ejection of the liquid medicine.

[0058] The first tip portion 72 is a portion to which the piston 30 is attached. In this embodiment, the first tip portion 72 is substantially cylindrical and has a male thread on its outer circumferential surface.

[0059] The second shaft portion 8 is a shaft body that is operated when discharging the medicinal liquid (see FIG. 2A ). The second shaft portion 8 is a member disposed within the first shaft portion 7. The second shaft portion 8 is biased toward the base end by the biasing force of the biasing member 4. The second shaft portion 8 has an axially asymmetric shape. The second shaft portion 8 is made of a resin such as POM (polyacetal). In this embodiment, the first shaft portion 7 and the second shaft portion 8 are made of the same material, but they may be made of different materials.

[0060] 2A to 2C, the second shank 8 includes a second main shank 80 extending along the axial direction and a second base end 81 provided at the base end of the second main shank 80. The second shank 8 also includes a restricting portion 83 having a starting end 830 at the distal end and a free end 831 at the proximal end. The restricting portion 83 is configured to be rotatable about the starting end 830 between a restricted retracted position where the free end 831 is located radially inward and a restricted deployed position where the free end 831 is located radially outward. The second shank 8 also includes a pushing portion 85 having a push-engaged portion 84 that engages with the push-engagement portion 77 of the first shank 7 when the plunger 3 is pushed in.

[0061] In this second shaft portion 8, the restricting portion 83 is provided on one circumferential side, and the pushing portion 85 is provided on the other circumferential side. Specifically, in this second shaft portion 8, the restricting portion 83 and the pushing portion 85 are provided at positions facing each other across the central axis. More specifically, the restricting portion 83 and the pushing portion 85 face each other at positions 180° apart in the circumferential direction of the second shaft portion 8.

[0062] The second shaft portion 8 also includes a discharge completion portion 87 having a discharge completion locked portion 86 that locks with the discharge completion locking portion 24 when the discharge of the medicinal liquid is completed.

[0063] In this second shaft portion 8, a protruding portion 88 is provided on one circumferential side, and a discharge completion portion 87 is provided on the other circumferential side. In addition, in this second shaft portion 8, the protruding portion 88 is aligned with the restricting portion 83 on the base end side in the axial direction. Furthermore, the discharge completion portion 87 is aligned with the pushing portion 85 on the tip side in the axial direction. In this embodiment, the second main shaft portion 80 is integrally molded with the second base end portion 81, the restricting portion 83, the pushing portion 85, the discharge completion portion 87, and the protruding portion 88. Note that the second main shaft portion 80 may be separate from at least one of these components and may be formed by combining separate members.

[0064] The second main shaft portion 80 is a portion that fits within the first main shaft portion 70 (see FIG. 2A). In this embodiment, the second main shaft portion 80 is generally cylindrical and has a recess 90 that fits the restricting portion 83 when the second main shaft portion 80 is in the restricting retracted position (see FIG. 2B). In addition to the recess 90 that fits the restricting portion 83, the second main shaft portion 80 also has a recess 91 that fits the pushing portion 85 when the second main shaft portion 80 is in the pushing retracted position. The tip of the second main shaft portion 80 abuts against the biasing member 4.

[0065] The restricting portion 83 is a stopper that prevents the second shaft portion 8 from moving relative to the first shaft portion 7 due to the biasing force of the biasing member 4. The radially outer end surface 8321 of the restricting portion 83 is an inclined surface that is located radially inward toward the distal end and radially outward toward the proximal end. This end surface 8321 is the surface that is pushed by the restriction release portion 5 when one push is completed. The restricting portion 83 also includes a restricting locked portion 82 at its free end 831 located on the proximal side. The restricting locked portion 82 is locked to the restricting locking portion 76 of the first shaft portion 7 by the biasing force of the biasing member 4 in the restricted deployment position. That is, the proximal end of the restricting portion 83 constitutes the restricting locked portion 82 (see FIGS. 2B and 2C). When the restricting portion 83 is in the restricted deployment position, the restricting locked portion 82 is locked to the restricting locking portion 76 (see FIGS. 1B and 1C). When the restricting portion 83 is in the restricting retracted position, the restricting locked portion 82 is not locked by the restricting locking portion 76 (see FIGS. 3A and 3C). Furthermore, the restricting portion 83 is provided on the second main shaft portion 80 (see FIGS. 2B and 2C).

[0066] In this embodiment, a pair of restricting and locked portions 82 are provided with a gap in the circumferential direction of the second main shaft portion 80 (see FIG. 1B). Furthermore, the surface of the restricting portion 83 facing the base end, specifically, the base end surface 820 of the restricting and locked portion 82, abuts against the tip end surface 760 of the restricting and locked portion 76 of the first shaft portion 7, thereby restricting movement of the second shaft portion 8 with respect to the first shaft portion 7 due to the biasing force (see FIG. 1C). The base end surface 820 of the restricting and locked portion 82 is a flat surface.

[0067] The restricting portion 83 also includes a restricting guided portion 832 provided between the pair of restricting locked portions 82 (see FIG. 1B ). The restricting portion 83 also includes a restricting extension portion 833 extending from the radially inner end of the restricting locked portion 82 toward the base end (see FIGS. 2B and 2C ).

[0068] The restricted guided portion 832 is a portion for guiding the movement of the second shaft portion 8 along the axial direction relative to the first shaft portion 7 when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4. In addition, the restricted guided portion 832 is a portion for restricting the movement of the second shaft portion 8 in the circumferential direction in a state in which the movement of the second shaft portion 8 relative to the first shaft portion 7 is restricted by the biasing force of the biasing member 4.

[0069] In this embodiment, the restricted guided portion 832 abuts against the one-side convex portions 732, 733, and 734 of the first shaft portion 7, thereby guiding the movement of the second shaft portion 8 along the axial direction and restricting the movement of the second shaft portion 8 in the circumferential direction. Specifically, an outer surface 8320 of the restricted guided portion 832 facing the circumferential direction of the second shaft portion 8 abuts against the guide surfaces 7320, 7330, and 7340 of the convex portions 732, 733, and 734 facing the one-side slit 700, thereby guiding the movement of the second shaft portion 8 along the axial direction and restricting the movement of the second shaft portion 8 in the circumferential direction. The outer surface 8320 of the restricted guided portion 832 is a flat surface. Furthermore, a radially outer end surface 8321 of the restricted guided portion 832 constitutes the radially outer end surface of the restricting portion 83. The radially outer end surface 8321 of the restricted guided portion 832 is a flat inclined surface.

[0070] The restricting extension 833 is a stopper that prevents the restricting portion 83 from opening radially outward when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4, and when the movement of the second shaft portion 8 relative to the first shaft portion 7 is restricted. The restricting extension 833 is located radially inward of a portion of the protrusion 88. In this embodiment, the restricting extension 833 is a rib that extends axially from the radially inner end of the restricting locked portion 82 toward the base end. An outer surface 8330 located radially outward of the restricting extension 833 is a flat surface.

[0071] Pushing portion 85 is provided on second main shaft portion 80. Pushing portion 85 has a starting end 850 on the base end side and a free end 851 on the tip end side. Pushing portion 85 is configured to be rotatable around starting end 850 between a pushing retracted position where free end 851 is located radially inward and a pushing deployed position where free end 851 is located radially outward. The radially outer end face of pushing portion 85 is an inclined surface that is located radially inward as it approaches the base end and radially outward as it approaches the tip end.

[0072] In this embodiment, the tip of the pushing portion 85 constitutes the push-in locked portion 84. The push-in locked portion 84 is a main shaft push-in locked portion 84 provided at a free end 851 of the pushing portion 85, and is configured as a main shaft push-in locked portion 84 that locks with the main shaft push-in locked portion 77 of the first shank 7 when pushed in the push-in deployed position. A pair of push-in locked portions 84 are provided around the second main shaft 80 with a gap between them (see FIG. 2D ). When the plunger 3 is pushed in, the surface of the pushing portion 85 facing the tip, specifically, the tip surface 840 of the push-in locked portion 84, abuts against the base end surface 770 of the push-in locked portion 77 of the first shank 7, thereby transmitting a force that moves the second shank 8 toward the tip to the first shank 7, and the first shank 7 moves together with the second shank 8 (see FIG. 5C ). The tip surface 840 of the push-in locked portion 84 is a flat surface.

[0073] Furthermore, the base end surface 841 of the pressed-in engagement portion 84, which faces the base end, is an inclined surface that is positioned radially inward as it approaches the base end (see FIG. 2B ). When the second shank 8 moves proximally relative to the first shank 7 due to the biasing force of the biasing member 4, the base end surface 841 of the pressed-in engagement portion 84 abuts against the distal end surfaces 7412, 7422, and 7432 of the other-side convex portions 741, 742, and 743 of the first shank 7, causing the pressing portion 85 to move from the pushed-in deployment position to the pushed-in retracted position (see FIGS. 3C , 5C , and 7C ). The base end surface 841 of the pressed-in engagement portion 84 is a flat inclined surface.

[0074] The pushing portion 85 includes a pushing guided portion 852 provided between the pair of pushing engaged portions 84 (see FIG. 2B ). The pushing portion 85 also includes a pushing extension portion 853 extending from the radially inner end of the pushing engaged portion 84 toward the tip side.

[0075] The pushed-in guided portion 852 is a portion that guides the movement of the second shaft portion 8 along the axial direction relative to the first shaft portion 7 when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4. The pushed-in guided portion 852 is also a portion that restricts the circumferential movement of the second shaft portion 8 in a state in which the movement of the second shaft portion 8 relative to the first shaft portion 7 is restricted by the biasing force of the biasing member 4.

[0076] In the present embodiment, the pressed-in guided portion 852 abuts against the other-side convex portions 741, 742, and 743 of the first shaft portion 7, thereby guiding the movement of the second shaft portion 8 along the axial direction and restricting the movement of the second shaft portion 8 in the circumferential direction. Specifically, an outer surface 8520 of the pressed-in guided portion 852 facing the circumferential direction of the second shaft portion 8 abuts against the guide surfaces 7410, 7420, and 7430 facing the other-side slit 701 of the convex portions 741, 742, and 743, thereby guiding the movement of the second shaft portion 8 along the axial direction and restricting the movement of the second shaft portion 8 in the circumferential direction. The outer surface 8520 of the pressed-in guided portion 852 is a flat surface.

[0077] The push-in extension 853 is a stopper that prevents the push-in portion 85 from opening radially outward when the second shank 8 moves relative to the first shank 7 due to the biasing force of the biasing member 4, and when the user of the syringe 1 moves the second shank 8 toward the tip. In this embodiment, the push-in extension 853 is a rib that extends axially from the radially inner end of the push-in engagement portion 84 toward the tip. The push-in extension 853 is also located radially inward of a portion of the discharge completion portion 87. A surface 8530 located radially outward of the push-in extension 853 is a flat surface.

[0078] Discharge completion portion 87 is a stopper that engages with discharge completion locking portion 24 of barrel 2 to restrict plunger 3 that has moved a distance corresponding to one discharge (see FIGS. 2B to 2D). In this embodiment, discharge completion portion 87 engages with discharge completion locking portion 24 upon completion of discharge of the liquid medicine excluding the final discharge. Discharge completion portion 87 is also provided on second main shaft portion 80.

[0079] In this embodiment, the tip of discharge completion portion 87 constitutes discharge completion locked portion 86. One discharge completion locked portion 86 is provided on second main shaft portion 80. Furthermore, the surface of discharge completion portion 87 facing the tip, specifically, tip surface 860 of discharge completion locked portion 86, abuts against base end surface 240 of discharge completion locking portion 24 of barrel 2, thereby completing the movement of second shaft portion 8 toward the tip by the user of syringe 1, i.e., completing one discharge of medicinal liquid. Tip surface 860 of discharge completion locked portion 86 is a flat surface.

[0080] The discharge completion portion 87 includes a discharge guided portion 870, which is the radially outer end portion (see FIGS. 2B and 2C). The discharge completion portion 87 also includes a discharge extension portion 871, which extends as the end portion on the base end side of the discharge guided portion 870 (see FIG. 2B).

[0081] The discharge guided portion 870 is a portion for guiding the movement of the second shaft portion 8 along the axial direction relative to the first shaft portion 7 when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4. The discharge guided portion 870 is also a portion for restricting the circumferential movement of the second shaft portion 8 in a state in which the movement of the second shaft portion 8 relative to the first shaft portion is restricted by the biasing force of the biasing member 4.

[0082] In the present embodiment, the discharge guided portion 870 comes into contact with the other-side convex portions 742, 743, and 744 of the first shaft portion 7, thereby guiding the movement of the second shaft portion 8 along the axial direction and restricting the movement of the second shaft portion 8 in the circumferential direction. Specifically, the outer surface 8700 of the discharge guided portion 870 facing the circumferential direction of the second shaft portion 8 comes into contact with the guide surfaces 7420, 7430, and 7440 facing the other-side slit 701 of the convex portions 742, 743, and 744, thereby guiding the movement of the second shaft portion 8 along the axial direction and restricting the movement of the second shaft portion 8 in the circumferential direction. The outer surface 8700 of the discharge guided portion 870 is a flat surface.

[0083] The ejection extension portion 871 is a stopper pressing portion that presses the pushing extension portion 853 of the pushing portion 85 to prevent the pushing portion 85 from opening radially outward when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4, and when the user of the syringe 1 moves the second shaft portion 8 toward the distal end. The ejection extension portion 871 is located radially outward of the pushing extension portion 853. In this embodiment, the ejection extension portion 871 is a rib that extends axially toward the proximal end as the proximal end end of the ejection guided portion 870. The radially inner inner surface 8710 of the ejection extension portion 871 is a flat surface. The inner surface 8710 of the ejection extension portion 871 abuts against the radially outer outer surface 8530 of the pushing extension portion 853, thereby preventing the pushing portion 85 from opening radially outward (see FIGS. 3B , 5B , and 7B ).

[0084] The protruding portion 88 is provided on the second main shaft portion 80. The protruding portion 88 is provided closer to the base end than the restricting portion 83 (see FIG. 2B ). The protruding portion 88 includes a protruding guided portion 880, which is the radially outer end. The protruding portion 88 also includes a protruding extension portion 881, which extends as the end on the tip side of the protruding guided portion 880.

[0085] The protruding guided portion 880 is a portion for guiding the movement of the second shaft portion 8 along the axial direction relative to the first shaft portion 7 when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4. The protruding guided portion 880 is also a portion for restricting the circumferential movement of the second shaft portion 8 in a state in which the movement of the second shaft portion 8 relative to the first shaft portion is restricted by the biasing force of the biasing member 4.

[0086] In the present embodiment, the protruding guided portion 880 abuts against the convex portions 731, 732, and 733 of the first shaft portion 7, thereby guiding the movement of the second shaft portion 8 along the axial direction and restricting the movement of the second shaft portion 8 in the circumferential direction. Specifically, an outer surface 8800 of the protruding guided portion 880 facing the circumferential direction of the second shaft portion 8 abuts against the guide surfaces 7310, 7320, and 7330 facing the one-side slit 700 side of the convex portions 731, 732, and 733, thereby guiding the movement of the second shaft portion 8 along the axial direction and restricting the movement of the second shaft portion 8 in the circumferential direction. The outer surface 8800 is a flat surface.

[0087] The protruding extension portion 881 is a stopper pressing portion that presses the restricting extension portion 833 of the restricting portion 83 to prevent the restricting portion 83 from opening radially outward when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4 and when the movement of the second shaft portion 8 relative to the first shaft portion 7 is restricted. The protruding extension portion 881 is located radially outward of the restricting extension portion 833. In this embodiment, the protruding extension portion 881 is a rib that extends axially toward the distal end of the protruding guided portion 880. An inner surface 8810 on the radially inner side of the protruding extension portion 881 is a flat surface. The inner surface 8810 of the protruding extension portion 881 abuts against the radially outer outer surface 8330 of the restricting extension portion 833, thereby preventing the restricting portion 83 from opening radially outward (see FIGS. 3B , 5B , and 7B ).

[0088] The second base end 81 overlaps with the first base end 71 of the first shank 7. In this embodiment, the second base end 81 extends radially outward from the entire outer periphery of the base end of the second main shaft 80. The second base end 81 is plate-shaped (e.g., disk-shaped) when viewed axially. In this syringe 1, the second base end 81 forms a push-in locked portion 84 that locks with the first base end 71 during the first ejection of the liquid medicine.

[0089] The biasing member 4 is an elastic member that is disposed inside the first shaft portion 7 together with the distal end portion of the second shaft portion 8. The biasing member 4 biases the second shaft portion 8 toward the proximal end side relative to the first shaft portion 7.

[0090] In this embodiment, the biasing member 4 is, for example, a spring (specifically, a metal spring) (see FIG. 2A). Specifically, the biasing member 4 is a compression spring.

[0091] The biasing member 4 may be a member other than a metal spring, such as a resin spring. When the syringe 1 includes a resin spring as the biasing member 4, the resin spring and the first shaft 7 may be integrally molded, or the resin spring and the second shaft 8 may be integrally molded.

[0092] When one push is completed, the deregulation unit 5 moves the restricting portion 83 from the extended restricting position to the retracted restricting position, thereby releasing the restricting locked portion 82 from the restricting locking portion 76 (see FIGS. 3B , 5B , and 7B ). In this embodiment, the deregulation unit 5 is provided on the barrel 2 and, specifically, is configured as a part of the finger grip 23. More specifically, the deregulation unit 5 is configured as a radially inner end 2321 of the grip main body 230 of the finger grip 23, for example, a radially inner end 2321 of the main body base end 232 of the grip main body 230. This end 2321 abuts against a radially outer end face 8321 of the restricting portion 83, moving the restricting portion 83 from the extended restricting position (radially outer position) to the retracted restricting position (radially inner position). Note that the deregulation unit 5 may be configured as a part of the barrel main body 22.

[0093] The pushing guide portion 6 guides the pushing portion 85 of the second shank 8 from the pushing deployed position to the pushing retracted position between two axially adjacent main shaft pushing locking portions 77 of the first shank 7. In the present embodiment, as described above, the pushing guide portion 6 is provided on the first main shaft portion 70 of the first shank 7, and more specifically, on the tip portions of the convex portions 741, 742, and 743 of the first shank 7 (see FIGS. 3C, 5C, and 7C).

[0094] The discharge nozzle 9 is a part that extracts the liquid medicine (see FIG. 1A ). The discharge nozzle 9 of this embodiment is configured to discharge the liquid medicine in the form of a mist. The discharge nozzle 9 is attached to the tip 20 of the barrel body 22. Specifically, the discharge nozzle 9 is attached to the body tip 220 of the barrel body 22 by press-fitting.

[0095] The operations and states when using the syringe 1 will be described in detail below.

[0096] As shown in FIGS. 1A to 1C , the initial state is a state in which the syringe 1 has not yet dispensed any liquid medicine. In the initial state, the second shank 8 is biased proximally relative to the first shank 7 by the biasing force of the biasing member 4, and the restricting portion 83 is in the restricted deployment position. Furthermore, the restricting interlocked portion 82 of the restricting portion 83 is engaged with the restricting interlocking portion 76 of the one-side protrusion 734, which is the fourth proximal protrusion 734 of the first shank 7, by the biasing force of the biasing member 4 (see FIG. 1C ). Specifically, the proximal end surface 820 of the restricting interlocked portion 82 of the restricting portion 83 is engaged with the distal end surface 7341 of the fourth proximal protrusion 734. This engagement restricts the movement of the second shank 8 proximally relative to the first shank 7. Note that in the initial state, the second proximal end 81 of the second shank 8 is disposed with a gap in the axial direction from the first proximal end 71 of the first shank 7.

[0097] When the user of syringe 1 pushes second shank 8 (specifically, second base end 81) toward the distal end from the initial state, first shank 7 is pushed toward the distal end together with second shank 8, resulting in the first ejection of medicinal solution, as shown in Figures 3A to 3C. Specifically, when the user pushes second base end 81 toward the distal end, second base end 81 moves toward the distal end until it abuts first base end 71. When the user further pushes second base end 81 toward the distal end, distal end surface 810, which is the surface of second base end 81 facing the distal end, abuts base end surface 710, which is the surface of first base end 71 facing the proximal end (see Figure 3A). Thereafter, when the user pushes second base end 81 toward the distal end, first shank 7 is pushed toward the distal end together with second shank 8 with distal end surface 810 of second base end 81 pressed against proximal end surface 710 of first base end 71, and the first ejection of medicinal solution is performed. That is, in the first ejection of medicinal solution, distal end surface 810 of second base end 81 is the locked surface of push-in locked portion 84, and proximal end surface 710 of first base end 71 is the locking surface of push-in locking portion 77. Note that from the initial state until immediately after the first ejection, second shank 8 is biased toward the proximal end with respect to first shank 7 by the biasing force of biasing member 4.

[0098] The first discharge of the liquid medicine is completed when the discharge completion locked portion 86 of the discharge completion portion 87 of the second shaft portion 8 is locked with the discharge completion locking portion 24 of the barrel 2 (see FIG. 3B ). Specifically, the first discharge of the liquid medicine is completed when the distal end surface 860 of the discharge completion locked portion 86 is locked with the proximal end surface 240 of the discharge completion locking portion 24.

[0099] During the first ejection of the liquid medicine, the restricting portion 83 of the second shaft portion 8 is moved from the restricted deployment position to the retracted position by the deregulating portion 5. Specifically, the radially outer end surface 8321 of the restricting portion 83 abuts against the deregulating portion 5 provided on the barrel 2 (in this embodiment, the radially inner end 2321 of the main body base end 232 of the finger grip 23), causing the restricting portion 83 to bend radially inward and move from the restricted deployment position to the restricted retracted position. This also causes the restricted locked portion 82 of the second shaft portion 8 to move radially inward, releasing the lock of the restricted locked portion 82 with the restricted locking portion 76 of the first shaft portion 7. The biasing force then moves the second shaft portion 8 toward the proximal end relative to the first shaft portion 7, resulting in the state immediately before the second ejection shown in FIGS. 4A and 4B .

[0100] Furthermore, during the first discharge, the restricting portion 83 is moved to the restricting retracted position by the restricting release portion 5, and then moves to the restricting deployed position between the restricting locking portion 76 that was previously locked for dispensing one dose of the contents and the (next) restricting locking portion 76 that is adjacent to the restricting locking portion 76 on the base end side in the axial direction (see FIG. 4B ). Specifically, after being moved to the restricting retracted position by the restricting release portion 5, the restricting portion 83 moves to the restricting deployed position between the restricting locking portion 76 of the one-side protrusion 734 that is fourth from the base end of the first shaft portion 7 and the restricting locking portion 76 of the one-side protrusion 733 that is third from the base end and that was locked in the initial state.

[0101] Furthermore, immediately after the first discharge, the pushing portion 85 of the second shank 8 is located distally of the other-side convex portion 743, which is the third from the proximal end (see FIG. 3C ). When the second shank 8 moves proximally relative to the first shank 7 due to the biasing force of the biasing member 4 and reaches a state immediately before the second discharge, the proximal end surface 841 of the pushing-engaged portion 84 of the pushing portion 85 abuts the distal end surface 7432 of the third other-side convex portion 743 from the proximal end of the first shank 7 (see FIG. 4B ). As a result, the pushing portion 85 is pushed radially inward to the pushed-in retracted position, passes the third other-side convex portion 743 from the proximal end, and moves proximally to between the second other-side convex portion 742 and the third other-side convex portion 743 from the proximal end. In this way, the pushing portion 85 is moved to the pushing retracted position by the tip surface 7432 of the third other-side convex portion 743, and then reaches the pushing deployed position at a position proximal to the third other-side convex portion 743 from the proximal end. When the pushing portion 85 is positioned proximally relative to the proximal-side main shaft pushing locking portion 77, the pushing guide portion 6 releases the holding of the pushing portion 85 in the pushing retracted position.

[0102] When the second shaft 8 moves toward the base end relative to the first shaft 7 due to the biasing force of the biasing member 4 so as to change from a state immediately after the first ejection to a state immediately before the second ejection, the restricted guided portion 832 moves while being guided by the fourth one-side convex portion 734 from the base end side. Specifically, the restricted guided portion 832 is guided by the guide surface 7340 of the one-side convex portion 734 that faces the one-side slit 700, and the second shaft 8 moves along the axial direction.

[0103] During this movement, the pressed-in guided portion 852 moves while being guided by the third other-side convex portion 743 from the base end. Specifically, the pressed-in guided portion 852 is guided by the guide surface 7430 of the other-side convex portion 743 that faces the other-side slit 701, and the second shaft portion 8 moves along the axial direction. During this movement, the discharge-guided portion 870 moves while being guided by the fourth other-side convex portion 744 from the base end. Specifically, the discharge-guided portion 870 is guided by the guide surface 7440 of the other-side convex portion 744 that faces the other-side slit 701, and the second shaft portion 8 moves along the axial direction. During this movement, the protruding-guided portion 880 moves while being guided by the third one-side convex portion 733 from the base end. Specifically, the protruding guided portion 880 is guided by the guide surface 7330 of the one-side convex portion 733 that faces the one-side slit 700, and the second shaft portion 8 moves along the axial direction.

[0104] Furthermore, during this movement, inner surface 8810 of protruding extension portion 881 abuts against outer surface 8330 on the radially outer side of restricting extension portion 833, thereby preventing restricting portion 83 from opening radially outward (see FIG. 3B ). Also, during this movement, inner surface 8710 of ejection extension portion 871 abuts against outer surface 8530 on the radially outer side of pushing extension portion 853, thereby preventing pushing portion 85 from opening radially outward.

[0105] Immediately before the second discharge, the restricting and locked portion 82 of the restricting portion 83 of the second shank 8 is locked by the biasing force of the biasing member 4 to the restricting and locked portion 76 of the one-side protrusion 733 that is the third from the base end of the first shank 7 (see FIG. 4B ). Specifically, the base end surface 820 of the restricting and locked portion 82 of the restricting portion 83 is locked to the tip end surface 7331 of the one-side protrusion 733 that is the third from the base end. This locking restricts movement of the second shank 8 relative to the first shank 7. Note that in this initial state, the second base end 81 of the second shank 8 is disposed with a gap in the axial direction from the first base end 71 of the first shank 7.

[0106] When the user of syringe 1 pushes second shank 8 (specifically, second base end 81) toward the distal end from a state immediately prior to the second ejection (see FIGS. 4A and 4B), as shown in FIGS. 5A to 5C , the first shank 7 is pushed toward the distal end together with second shank 8, resulting in the second ejection of medicinal liquid. Specifically, when the user pushes second base end 81 toward the distal end, the distal end surface 840 of push-in locking portion 84 abuts against the proximal end surface 770 of push-in locking portion 77 of first shank 7, and the first shank 7 is pushed toward the distal end together with second shank 8, resulting in the second ejection of medicinal liquid (see FIG. 5C ). Specifically, distal end surface 840 abuts against the proximal end surface 7431 of the other-side protrusion 743, which is the third from the proximal end. During the period from immediately before the second ejection to immediately after the second ejection, the second shaft portion 8 is biased toward the base end side relative to the first shaft portion 7 by the biasing force of the biasing member 4 .

[0107] The second discharge of the liquid medicine is completed when the distal end surface 860 of the discharge completion locking portion 86 locks with the proximal end surface 240 of the discharge completion locking portion 24 (see FIG. 5B ). During the second discharge of the liquid medicine, the restricting portion 83 of the second shank 8 is deflected radially inward as the radially outer end surface 8321 of the restricting portion 83 contacts the radially inner end portion 2321 of the main body proximal end 232 of the finger grip 23, and is moved from the extended restricting position to the retracted restricting position. This also moves the restricting locked portion 82 of the second shank 8 radially inward, releasing the lock of the restricting locked portion 82 with the restricting locking portion 76 of the first shank 7. The biasing force then moves the second shank 8 proximally relative to the first shank 7, resulting in the state immediately before the third discharge shown in FIGS. 6A and 6B .

[0108] Also, during the second ejection, the regulating portion 83 is moved to the regulating retracted position by the regulating release portion 5, and then moves to the regulating deployed position between the regulating locking portion 76 of the one-side convex portion 733 that is third from the base end of the first shaft portion 7 and that was engaged immediately before the second ejection, and the regulating locking portion 76 of the one-side convex portion 732 that is second from the base end.

[0109] Furthermore, just before the third discharge, the base end surface 841 of the pushed-in locked portion 84 of the pushing portion 85 comes into contact with the tip end surface 7422 of the other-side convex portion 742 that is second from the base end of the first shaft portion 7, causing the pushing portion 85 to be pushed radially inward and assume the pushed-in retracted position (see FIG. 6B ). As a result, the pushing portion 85 passes the second other-side convex portion 742 from the base end toward the base end, and moves between the other-side convex portion 741 located most proximal to the other-side convex portion 742 that is second from the base end.

[0110] When the second shaft 8 moves toward the base end relative to the first shaft 7 due to the biasing force of the biasing member 4 to move from a state immediately after the second discharge to a state immediately before the third discharge, the restricting guided portion 832 is guided by the guide surface 7330 of the one-side convex portion 734 that is third from the base end, and the second shaft 8 moves along the axial direction. During this movement, the pushing-in guided portion 852 is guided by the guide surface 7420 of the other-side convex portion 742 that is second from the base end, and the second shaft 8 moves along the axial direction. During this movement, the ejection-guided portion 870 is guided by the guide surface 7430 of the other-side convex portion 743 that is third from the base end, and the second shaft 8 moves along the axial direction. During this movement, the protruding guided portion 880 is guided by the guide surface 7320 of the one-side convex portion 732 that is second from the base end, and the second shaft 8 moves along the axial direction.

[0111] Furthermore, during this movement, inner surface 8810 of protruding extension portion 881 abuts against outer surface 8330 on the radially outer side of restricting extension portion 833, thereby preventing restricting portion 83 from opening radially outward (see FIG. 5B ). Also, during this movement, inner surface 8710 of ejection extension portion 871 abuts against outer surface 8530 on the radially outer side of pushing extension portion 853, thereby preventing pushing portion 85 from opening radially outward.

[0112] Immediately before the third discharge, the restricting and locked portion 82 of the restricting portion 83 of the second shank 8 is locked by the biasing force of the biasing member 4 to the restricting and locked portion 76 of the one-side protrusion 732 that is second from the base end of the first shank 7 (see FIG. 6B ). Specifically, the base end surface 820 of the restricting and locked portion 82 of the restricting portion 83 is locked to the tip end surface 7321 of the one-side protrusion 732 that is second from the base end. This locking restricts movement of the second shank 8 relative to the first shank 7. Note that in this state, the second base end 81 of the second shank 8 is disposed with a gap in the axial direction from the first base end 71 of the first shank 7.

[0113] When the user of syringe 1 pushes second shank 8 (specifically, second base end 81) toward the distal end from a state immediately prior to the third ejection (see FIGS. 6 and 6B ), as shown in FIGS. 7A to 7C , the first shank 7 is pushed toward the distal end together with second shank 8, resulting in the third ejection of the medicinal solution. Specifically, when the user pushes second base end 81 toward the distal end, the distal end surface 840 of push-in engaging portion 84 abuts against the proximal end surface 7421 of the second other-side protrusion 742 from the proximal end, and the first shank 7 is pushed toward the distal end together with second shank 8 (see FIG. 7C ). Note that from the state immediately prior to the third ejection until immediately after the third ejection, second shank 8 is biased toward the proximal end relative to first shank 7 by the biasing force of biasing member 4.

[0114] The third discharge of the liquid medicine is completed when the distal end surface 860 of the discharge completion locking portion 86 locks with the proximal end surface 240 of the discharge completion locking portion 24 (see FIG. 7B ). During the third discharge of the liquid medicine, the restricting portion 83 of the second shank 8 is deflected radially inward as the radially outer end surface 8321 of the restricting portion 83 contacts the radially inner end portion 2321 of the main body proximal end 232 of the finger grip 23, and is moved from the extended restricting position to the retracted restricting position. This also moves the restricting locked portion 82 of the second shank 8 radially inward, releasing the lock of the restricting locked portion 82 with the restricting locking portion 76 of the first shank 7. This causes the biasing force to move the second shank 8 toward the proximal end relative to the first shank 7, resulting in the state immediately before the fourth discharge shown in FIGS. 8A and 8B .

[0115] Also, during the third ejection, the restricting portion 83 is moved to the restricting retracted position by the restricting release portion 5, and then moves to the restricting deployed position between the restricting locking portion 76 of the one-side convex portion 732 second from the base end of the first shaft portion 7, which was engaged just before the third ejection, and the restricting locking portion 76 of the one-side convex portion 731 located closest to the base end.

[0116] Furthermore, just before the fourth discharge, the base end surface 841 of the pushed-in locked portion 84 of the pushing portion 85 comes into contact with the tip end surface 7412 of the other-side convex portion 741 located most proximal to the first shaft portion 7, causing the pushing portion 85 to be pushed radially inward to the pushed-in retracted position (see FIG. 8B ). As a result, the pushing portion 85 passes the other-side convex portion 741 located most proximal to the base end side, and moves more proximal than the other-side convex portion 741 located most proximal.

[0117] When the second shaft 8 moves toward the base end relative to the first shaft 7 due to the biasing force of the biasing member 4 to move from a state immediately after the third ejection to a state immediately before the fourth ejection, the restricting guided portion 832 is guided by the guide surface 7320 of the one-side convex portion 732 second from the base end, and the second shaft 8 moves along the axial direction. During this movement, the pushing-in guided portion 852 is guided by the guide surface 7410 of the other-side convex portion 741 located most proximally, and the second shaft 8 moves along the axial direction. During this movement, the ejection-guided portion 870 is guided by the guide surface 7420 of the other-side convex portion 742 second from the base end, and the second shaft 8 moves along the axial direction. During this movement, the protruding guided portion 880 is guided by the guide surface 7310 of the one-side convex portion 731 located most proximally, and the second shaft 8 moves along the axial direction.

[0118] Furthermore, during this movement, inner surface 8810 of protruding extension portion 881 abuts against outer surface 8330 on the radially outer side of restricting extension portion 833, thereby preventing restricting portion 83 from opening radially outward (see FIG. 7B ). Also, during this movement, inner surface 8710 of ejection extension portion 871 abuts against outer surface 8530 on the radially outer side of pushing extension portion 853, thereby preventing pushing portion 85 from opening radially outward.

[0119] Immediately before the fourth discharge, the restricting and locked portion 82 of the restricting portion 83 of the second shank 8 is locked by the biasing force of the biasing member 4 to the restricting and locked portion 76 of the one-side convex portion 731 located most proximal of the first shank 7 (see FIG. 8B ). Specifically, the base end surface 820 of the restricting and locked portion 82 of the restricting portion 83 is locked to the tip end surface 7311 of the one-side convex portion 731 located most proximal. This locking restricts movement of the second shank 8 relative to the first shank 7. Note that in this state, the second base end portion 81 of the second shank 8 is disposed with a gap in the axial direction from the first base end portion 71 of the first shank 7.

[0120] When the user of syringe 1 pushes second shank 8 (specifically, second base end 81) toward the distal end from a state immediately prior to the fourth ejection (see FIGS. 8 and 8B ), as shown in FIGS. 9A and 9B , first shank 7 is pushed toward the distal end together with second shank 8, resulting in the second ejection of medicinal solution. Specifically, when the user pushes second base end 81 toward the distal end, distal end surface 840 of push-in engaging portion 84 abuts proximal end surface 7411 of other-side convex portion 741, which is located most proximally, and first shank 7 is pushed toward the distal end together with second shank 8 (see FIG. 9B ). Note that from the state immediately prior to the fourth ejection until immediately after the fourth ejection, second shank 8 is biased toward the proximal end relative to first shank 7 by the biasing force of biasing member 4.

[0121] The fourth ejection of the liquid medicine is completed when the piston 30 provided at the first tip portion 72 of the first shaft portion 7 hits the tip portion of the main body connecting portion 222 of the barrel main body 22.

[0122] According to the syringe 1 described above, the engagement between the restricting locking portion 76 and the restricting locked portion 82 restricts the movement of the second shaft portion 8 toward the base end relative to the first shaft portion 7 due to the biasing force of the biasing member 4, and when the user presses the plunger 3 to perform the second, third, or fourth ejection, the engagement between the pushing locking portion 77 and the pushing locked portion 84 ensures that the entire plunger 3 can be pushed in and ejected. Furthermore, at the position where one push (discharge) is completed, the restriction release portion 5 releases the engagement between the restriction locking portion 76 and the restriction locked portion 82, so that the second shaft 8 moves toward the base end relative to the first shaft 7 by the biasing force of the biasing member 4, and the restriction locked portion 82 forms a next engagement (restriction) with the next restriction locking portion 76 located axially proximal to the restriction locking portion 76 that was engaged (previously engaged) for administering one dose of the contents, and the push-in locking portion 77 and the push-in locked portion 84 form a next engagement (pushing). In this way, the syringe 1 is reliably switched to prepare for the next discharge, so that multiple discharges can be reliably performed.

[0123] In the syringe 1 of this embodiment, after one dose of ejection is completed and the regulating portion 83 of the second shaft portion 8 is moved to the regulating retracted position by the regulating release portion 5, it switches to the regulating deployed position at the tip side of the (next) regulating locking portion 76 located on the base end side in the axial direction relative to the regulating locking portion 76 that was locked for administering one dose of contents, so that the regulating locked portion 82 is securely locked to the next regulating locking portion 76.

[0124] Furthermore, in the syringe 1 of this embodiment, the pushing portion 85 of the second shaft 8 rotates between the pushing deployed position and the pushing retracted position, thereby switching between engagement and disengagement between the main shaft pushing locking portion 77 of the first shaft 7 and the main shaft pushing locked portion 84 of the second shaft 8. Therefore, after one discharge is completed, the main shaft pushing locked portion 84 is reliably locked to the next main shaft pushing locking portion 77 located axially closer to the base end than the previously locked main shaft pushing locking portion 77.

[0125] Furthermore, in the syringe 1 of this embodiment, the pushing portion 85 switches to the pushing-out position at a position on the axial base end side of the next main shaft pushing-in locking portion 77, so that after one discharge is completed, the main shaft pushing-in locking portion 84 is securely locked to the next main shaft pushing-in locking portion 77.

[0126] The syringe of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the configuration of one embodiment can be added to the configuration of another embodiment, or part of the configuration of one embodiment can be replaced with the configuration of another embodiment. Furthermore, part of the configuration of one embodiment can be deleted.

[0127] For example, the configuration of each component of the syringe 1 may be different from the configuration described above. In the above embodiment, the first shaft portion 7 and the second shaft portion 8 of the plunger 3 have an asymmetric shape about their axis, but they may have an axially symmetric shape.

[0128] Hereinafter, a configuration in which first shaft portion 7 and second shaft portion 8 have an axisymmetric shape and syringe 1 administers a drug solution in two divided doses will be described with reference to FIGS. 10 to 15B.

[0129] In this configuration, the finger grip 23 includes, in addition to the grip main body 230 and a pair of grip extensions 231, an annular grip proximal extension 234 that extends from the radially inner end of the grip main body 230 toward the proximal end and surrounds the plunger 3 (see FIGS. 10 and 11A). The finger grip 23 also includes the grip proximal extension 234 as an ejection completion locking portion 24 that locks with the plunger 3 upon completion of the first ejection of the syringe 1 (see FIG. 13B). The proximal surface 240 of the ejection completion locking portion 24 is formed by a proximal surface 2340 that faces the proximal end of the grip proximal extension 234. Specifically, two locations on the proximal surface 2340 that face each other across the center line of the grip main body 230 are the locations where the plunger 3 is locked. In this embodiment, the base end surfaces 240 of the discharge completion locking portions 24 face each other at positions 180° apart in the circumferential direction of the finger grip 23 .

[0130] 11C , the first shank 7 includes a first main shank 70, a first base end 71, and a first tip end 72, as well as a plurality of protrusions 75 provided on one side and the other side of the first main shank 70. Two pairs of protrusions 75 are provided on the first main shank 70, with slits 700, 701 between them and spaced apart in the axial direction. The protrusions 75 all protrude the same distance from the slits 700, 701. The protrusion 751 provided on the base end side has a larger axial dimension than the protrusion 752 provided on the tip end side.

[0131] The convex portions 75 each guide the movement of the second shaft portion 8 along the axial direction relative to the first shaft portion 7 when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4. Furthermore, the convex portions 75 restrict the circumferential movement of the second shaft portion 8 while the movement of the second shaft portion 8 relative to the first shaft portion 7 is restricted by the biasing force of the biasing member 4. Each of the convex portions 751, 752 has guide surfaces 7510, 7520 facing the slits 700, 701 that abut against a part of the second shaft portion 8, thereby guiding the movement of the second shaft portion 8 along the axial direction and restricting the circumferential movement of the second shaft portion 8. The guide surfaces 7510, 7520 of the convex portions 75 are flat surfaces.

[0132] The protrusions 751, 752 include a restricting locking portion 76 that restricts movement of the second shaft portion 8 relative to the first shaft portion 7 due to the biasing force of the biasing member 4. In this embodiment, the tip of each of the protrusions 751, 752 constitutes the restricting locking portion 76. Tip surfaces 7511, 7521, which are surfaces facing the tip of the protrusions 751, 752, constitute a tip surface 760 of the restricting locking portion 76. The tip surface 760 of the restricting locking portion 76 abuts against a part of the second shaft portion 8, thereby restricting movement of the second shaft portion 8 relative to the first shaft portion 7 due to the biasing force. The tip surface 760 is a flat surface.

[0133] The restricting locking portions 76 are provided in pairs spaced apart in the axial direction across the central axis of the first shaft portion 7. Specifically, the restricting locking portions 76 are made up of two pairs of spindle restricting locking portions 76 lined up in the axial direction across the central axis of the first shaft portion 7. In this embodiment, the restricting locking portions 76 face each other at positions spaced 180° apart in the circumferential direction of the first shaft portion 7.

[0134] The protrusion 751 located on the base end side includes a push-in locking portion 77 that locks with the second shank 8 when the plunger 3 is pushed into the barrel 2. A set of push-in locking portions 77 is provided in the axial direction. In this embodiment, the base end of the protrusion 751 constitutes the push-in locking portion 77. A base end surface 7512, which is the surface of the protrusion 751 facing the base end, constitutes a base end surface 770 of the push-in locking portion 77. The base end surface 770 of the push-in locking portion 77 comes into contact with a part of the second shank 8, thereby restricting movement of the second shank 8 toward the axial tip side relative to the first shank 7 and enabling the plunger 3 to be pushed into the barrel 2. The base end surface 770 of the push-in locking portion 77 is a flat surface.

[0135] The push-in locking portions 77 are provided in pairs on either side of the central axis of the first shaft portion 7. Specifically, the push-in locking portions 77 face each other at positions 180° apart in the circumferential direction of the first shaft portion 7. In this embodiment, the push-in locking portions 77 are made up of a pair of main shaft push-in locking portions 77.

[0136] In this embodiment, the protruding portion 751 located on the base end side includes a pushing guide portion 6 that guides a portion of the second shank 8 from the pushing-in deployment position to the pushing-in retraction position. The tip of the protruding portion 751 constitutes the pushing guide portion 6. A tip surface 7511, which is the surface of the protruding portion 751 facing the tip side, constitutes the tip surface 600 of the pushing guide portion 6. The pushing guide portion 6 guides a portion of the second shank 8 from the pushing-in deployment position to the pushing-in retraction position by the tip surface 600 of the pushing guide portion 6 coming into contact with a portion of the second shank 8.

[0137] The pushing guide parts 6 are provided in pairs on either side of the central axis of the first shaft part 7. Specifically, the pushing guide parts 6 face each other at positions 180° apart in the circumferential direction of the first shaft part 7. In this embodiment, the pushing guide parts 6 are made up of spindle pushing guide parts 6 that are provided in pairs on either side of the central axis of the first shaft part 7.

[0138] In addition, in this syringe 1, the first base end portion 71 forms a push-in locking portion 77 that locks onto a part of the second base end portion 81 during the first ejection of the liquid medicine.

[0139] 11B , in addition to the second main shaft portion 80 and the second base end portion 81, the second shank 8 also includes a restricting portion 83 having a starting end 830 at the distal end and a free end 831 at the proximal end. The restricting portion 83 is configured to be rotatable around the starting end 830 between a restricted retracted position where the free end 831 is located radially inward and a restricted deployed position where the free end 831 is located radially outward. The second shank 8 also includes a pushing portion 85 having a pushed-in locked portion 84 that locks with the pushed-in locking portion 77 of the first shank 7 when the plunger 3 is pushed in. The second shank 8 also includes a discharge completion portion 87 having a discharge completion locked portion 86 that locks with the discharge completion locking portion 24 when the discharge of the medicinal liquid is completed, and a protruding portion 89.

[0140] In this second shaft portion 8, the restricting portions 83 are provided in pairs at positions facing each other across the circumferential central axis of the second main shaft portion 80. Specifically, the restricting portions 83 are opposed at positions 180° apart in the circumferential direction of the second main shaft portion 80. Similarly, the pushing portion 85, the discharge completion portion 87, and the protruding portions 88 and 89 are provided in pairs at positions facing each other across the circumferential central axis of the second main shaft portion 80. Specifically, at least one of the pushing portion 85, the discharge completion portion 87, and the protruding portions 88 and 89, and in this embodiment, all of these, are opposed at positions 180° apart in the circumferential direction of the second main shaft portion 80. In addition, in this second shaft portion 8, the protruding portion 89, the pushing portion 85, the discharge completion portion 87, and the restricting portion 83 are aligned in this order from the base end to the tip end in the axial direction.

[0141] In this embodiment, the second main shaft portion 80 includes a second main wall portion 800 having a generally rectangular plate shape extending along the axial direction, and a second sub-wall portion 801 extending perpendicular to the second main wall portion 800 at the center of the width direction of the second main wall portion 800. The second main wall portion 800 has a partially cut-out shape, with the remaining portion forming the protrusion portion 89, the pushing portion 85, the discharge completion portion 87, and the restricting portion 83. The second sub-wall portion 801 fits onto the first shaft portion 7. This fit restricts circumferential movement of the second shaft portion 8 while restricting movement of the second shaft portion 8 relative to the first shaft portion 7 due to the biasing force of the biasing member 4. This fit also restricts circumferential movement of the second shaft portion 8 when the plunger 3 is pushed in or when the second shank 8 moves axially relative to the first shank 7 due to the biasing force.

[0142] The restricting portion 83 includes a restricting locked portion 82 at its free end 831, which is locked to the restricting locking portion 76 of the first shaft 7 by the biasing force of the biasing member 4 in the restricting deployed position. In this embodiment, the base end of the restricting portion 83 constitutes the restricting locked portion 82. When the restricting portion 83 is in the restricting deployed position, the restricting locked portion 82 is locked to the restricting locking portion 76 (see FIGS. 12B and 14B ). Furthermore, when the restricting portion 83 is in the restricting retracted position, the restricting locked portion 82 is not locked to the restricting locking portion 76.

[0143] In this embodiment, a pair of restricting and locked portions 82 are provided on the restricting portion 83 (see FIG. 11B). The surface of the restricting portion 83 facing the base end, specifically, the base end surface 820 of the restricting and locked portion 82, abuts against the distal end surface 760 of the restricting and locked portion 76 of the first shank 7, thereby restricting movement of the second shank 8 relative to the first shank 7 due to the biasing force (see FIGS. 12B and 14B). The base end surface 820 of the restricting and locked portion 82 is a flat surface.

[0144] The restricting portion 83 includes a restricting guided portion 832 provided radially outward of the pair of restricting locked portions 82 (see FIG. 11B ). The restricting portion 83 also includes a restricting extension portion 833 extending from the radially inner end of the restricting locked portion 82 toward the base end.

[0145] The regulated guided portion 832 is a portion for guiding the movement of the second shaft portion 8 along the axial direction relative to the first shaft portion 7 when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4.

[0146] In the present embodiment, the restricted guided portion 832 comes into contact with the convex portion 752 of the first shaft portion 7, thereby guiding the movement of the second shaft portion 8 along the axial direction. Specifically, the outer surface 8320 of the restricted guided portion 832 facing the circumferential direction of the second shaft portion 8 comes into contact with the guide surface 7520 of the convex portion 752 facing the slits 700, 701, thereby guiding the movement of the second shaft portion 8 along the axial direction. The outer surface 8320 of the restricted guided portion 832 is a flat surface.

[0147] The restricting extension 833 is a stopper that prevents the restricting portion 83 from opening radially outward when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4, and when the movement of the second shaft portion 8 relative to the first shaft portion 7 is restricted. The restricting extension 833 is also located radially inside a portion of the discharge completion portion 87. In this embodiment, the restricting extension 833 is a rib that extends axially from the radially inside end of the restricting locked portion 82 toward the base end. An outer surface 8330 located radially outside the restricting extension 833 is a flat surface.

[0148] The pushing portion 85 has a starting end 850 on the base end side and a free end 851 on the tip end side, and is configured to be rotatable around the starting end 850 between a pushing retracted position where the free end 851 is located radially inward and a pushing deployed position where the free end 851 is located radially outward. In this embodiment, the tip end of the pushing portion 85 constitutes the pushing locked portion 84. The pushing locked portion 84 is a spindle pushing locked portion 84 provided at the free end 851 of the pushing portion 85, and is configured as the spindle pushing locked portion 84 that locks with the spindle pushing locked portion 77 of the first shaft portion 7 when pushed in at the pushing deployed position.

[0149] One push-in locked portion 84 is provided for each push-in portion 85. When the plunger 3 is pushed in, the surface of the push-in portion 85 facing the tip, specifically the tip surface 840 of the push-in locked portion 84, comes into contact with the base end surface 770 of the push-in locked portion 77 of the first shank 7, and a force moving the second shank 8 toward the tip is transmitted to the first shank 7, causing the first shank 7 to move together with the second shank 8 (see FIG. 15B ). The tip surface 840 of the push-in locked portion 84 is a flat surface.

[0150] Furthermore, the base end surface 841 of the pressed-in interlocking portion 84, which faces the base end, is an inclined surface that is positioned radially inward as it approaches the base end. When the second shank 8 moves toward the base end relative to the first shank 7 due to the biasing force of the biasing member 4, the base end surface 841 of the pressed-in interlocking portion 84 comes into contact with the tip end surface 7511, which faces the tip end of the protrusion 751 of the first shank 7, causing the pressing portion 85 to move from the pressed-in deployed position to the pressed-in retracted position (see FIG. 13C ). The base end surface 841 of the pressed-in interlocking portion 84 is a flat surface.

[0151] The pushing portion 85 includes a pushing extension portion 853 that extends from the radially inner end of the pushing engagement portion 84 toward the tip side (see FIG. 11B).

[0152] The push-in extension portion 853 is a stopper that prevents the push-in portion 85 from opening radially outward when the second shank 8 moves relative to the first shank 7 due to the biasing force of the biasing member 4, and when the user of the syringe 1 moves the second shank 8 toward the tip. In this embodiment, the push-in extension portion 853 is a rib that extends axially from the radially inner end of the push-in engagement portion 84 toward the tip. The push-in extension portion 853 is also located radially inward of a portion of the discharge completion portion 87. An outer surface 8530 located radially outward of the push-in extension portion 853 is a flat surface.

[0153] The ejection completion portion 87 is a stopper that engages with the ejection completion locking portion 24 of the barrel 2, thereby restricting the plunger 3 from moving a distance corresponding to one ejection (see FIGS. 13A and 13B ). In this embodiment, the tip of the ejection completion portion 87 constitutes the ejection completion locked portion 86. A set of the ejection completion locked portions 86 is provided on the second main shaft portion 80. Furthermore, the surface of the ejection completion portion 87 facing the tip, specifically, the tip surface 860 of the ejection completion locked portion 86, abuts against the base end surface 240 of the ejection completion locking portion 24 of the barrel 2, thereby completing the movement of the plunger 3 toward the tip by the user of the syringe 1, i.e., the first ejection of the medicinal liquid (see FIG. 13B ). The tip surface 860 of the ejection completion locked portion 86 is a flat surface.

[0154] The discharge completion portion 87 includes a discharge guided portion 870, which is the radially outer end portion (see FIG. 11B ). The discharge completion portion 87 also includes discharge extension portions 871 and 872, which extend as the proximal and distal ends of the discharge guided portion 870, respectively.

[0155] The discharge guided portion 870 is a portion for guiding the movement of the second shaft portion 8 along the axial direction relative to the first shaft portion 7 when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4. The discharge guided portion 870 is also a portion for restricting the circumferential movement of the second shaft portion 8 in a state in which the movement of the second shaft portion 8 relative to the first shaft portion is restricted by the biasing force of the biasing member 4.

[0156] In the present embodiment, the discharge guided portion 870 comes into contact with the convex portion 752 on the tip side of the first shaft portion 7, thereby guiding the movement of the second shaft portion 8 along the axial direction and restricting the movement of the second shaft portion 8 in the circumferential direction. Specifically, the outer surface 8700 of the discharge guided portion 870 facing the circumferential direction of the second shaft portion 8 comes into contact with the guide surface 7520 of the convex portion 752 facing the slits 700, 701, thereby guiding the movement of the second shaft portion 8 along the axial direction and restricting the movement of the second shaft portion 8 in the circumferential direction. The outer surface 8700 of the discharge guided portion 870 is a flat surface.

[0157] The ejection extension portion 871 is a stopper pressing portion that presses the push-in extension portion 853 of the pushing portion 85 to prevent the pushing portion 85 from opening radially outward when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4, and when the user of the syringe 1 moves the second shaft portion 8 toward the distal end (see FIG. 11B ). The ejection extension portion 871 is located radially outward of the push-in extension portion 853. In this embodiment, the ejection extension portion 871 is a rib that extends axially toward the proximal end as the proximal end of the ejection guided portion 870. The radially inner inner surface 8710 of the ejection extension portion 871 is a flat surface. The inner surface 8710 of the ejection extension portion 871 abuts against the radially outer outer surface 8530 of the push-in extension portion 853, thereby preventing the pushing portion 85 from opening radially outward.

[0158] The discharge extension portion 872 is a stopper pressing portion that presses the restricting extension portion 833 of the restricting portion 83 to prevent the restricting portion 83 from opening radially outward when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4 and when the movement of the second shaft portion 8 relative to the first shaft portion 7 is restricted. The discharge extension portion 872 is located radially outward of the restricting extension portion 833. In this embodiment, the discharge extension portion 872 is a rib that extends axially toward the distal end of the discharge guided portion 870. The radially inner inner surface 8720 of the discharge extension portion 872 is a flat surface. The inner surface 8720 of the discharge extension portion 872 abuts against the radially outer outer surface 8330 of the restricting extension portion 833, thereby preventing the restricting portion 83 from opening radially outward.

[0159] The protruding portion 89 is provided on the second main shaft portion 80. The protruding portion 89 also includes a protruding guided portion 890 that is the radially outer end portion.

[0160] The protruding guided portion 890 is a portion for guiding the movement of the second shaft portion 8 in the axial direction relative to the first shaft portion 7 when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4. The protruding guided portion 890 is also a portion for restricting the circumferential movement of the second shaft portion 8 in a state in which the movement of the second shaft portion 8 relative to the first shaft portion is restricted by the biasing force of the biasing member 4.

[0161] In this embodiment, the protruding guided portion 890 comes into contact with the convex portion 751 on the base end side of the first shaft portion 7, thereby guiding movement of the second shaft portion 8 along the axial direction and restricting movement of the second shaft portion 8 in the circumferential direction. Specifically, an outer surface 8900 of the protruding guided portion 890 facing the circumferential direction of the second shaft portion 8 comes into contact with the guide surface 7510 of the convex portion 751 facing the slits 700, 701, thereby guiding movement of the second shaft portion 8 along the axial direction and restricting movement of the second shaft portion 8 in the circumferential direction. The outer surface 8900 is a flat surface.

[0162] When one push is completed, the deregulating unit 5 moves the restricting unit 83 from the extended restricting position to the retracted restricting position, thereby releasing the restricting locked unit 82 from the restricting locking unit 76 (see FIG. 13B ). In this embodiment, the deregulating unit 5 is configured by the radially inner end 2321 of the grip body 230 of the finger grip 23, for example, the radially inner end 2321 of the body base end 232 of the grip body 230.

[0163] The pushing guide 6 guides the pushing portion 85 of the second shank 8 from the pushing deployed position to the pushing retracted position when the pushing portion 85 rides over the proximal-side convex portion 751 from the distal side to the proximal side. In the present embodiment, as described above, the pushing guide 6 is provided on the main shank 70 of the first shank 7, and more specifically, on the distal end surface 7511 of the convex portion 751 of the first shank 7 (see FIG. 13C ).

[0164] The operations and states when using the syringe 1 will be described in detail below.

[0165] 10 , 12A, and 12B , the initial state is a state in which the syringe 1 has not yet ejected any liquid medicine. In the initial state, the restricting and locked portion 82 of the restricting portion 83 of the second shank 8 is locked by the biasing force of the biasing member 4 to the restricting and locked portion 76 of the protrusion 752 on the distal end side of the first shank 7. Specifically, the base end surface 820 of the restricting and locked portion 82 of the restricting portion 83 is locked to the distal end surface 7521 of the protrusion 752 on the distal end side (see FIG. 12B ). This locking restricts movement of the second shank 8 relative to the first shank 7.

[0166] When the user of syringe 1 pushes second base end 81 toward the tip from the initial state, first shaft portion 7 is pushed toward the tip together with second shaft portion 8, and the first ejection of medicinal liquid is performed, as shown in Figures 13A to 13C.

[0167] The first ejection of liquid medicine is completed when ejection completion locked portion 86 of ejection completion section 87 is locked with ejection completion locking portion 24 of barrel 2. Specifically, the first ejection of liquid medicine is completed when distal end surface 860 of ejection completion locked portion 86 is locked with proximal end surface 240 of ejection completion locking portion 24 (see FIG. 13B ).

[0168] During the first ejection of the liquid medicine, the restricting portion 83 of the second shaft 8 is moved from the extended position to the retracted position by the derestricting portion 5. Specifically, the radially outer end surface 8321 of the restricting portion 83 abuts against the radially inner end 2321 of the main body base end 232 of the finger grip 23, causing the restricting portion 83 to bend and move from the extended position to the retracted position. This also causes the restricted locked portion 82 of the second shaft 8 to move radially inward, releasing the lock of the restricted locked portion 82 with the restricted locking portion 76 of the first shaft 7. The biasing force of the biasing member 4 then causes the second shaft 8 to move proximally relative to the first shaft 7, resulting in the state immediately before the second ejection shown in FIGS. 14A and 14B .

[0169] Furthermore, during the first ejection, the restricting portion 83 is moved to the restricting retracted position by the restricting release portion 5, and then moves to the restricting deployed position between the restricting locking portion 76 of the protrusion 752 on the tip side of the first shaft portion 7, which was locked in the initial state, and the restricting locking portion 76 of the protrusion 751 on the base side.

[0170] Furthermore, immediately after the first discharge, the pushing portion 85 of the second shank 8 is located distally of the proximal convex portion 751 (see FIG. 13C ). When the second shank 8 moves proximally relative to the first shank 7 due to the biasing force of the biasing member 4 and reaches a state immediately before the second discharge, the proximal end surface 841 of the pushing-engaged portion 84 of the pushing portion 85 abuts the distal end surface 7511 of the proximal convex portion 751, forcing the pushing portion 85 radially inward to the pushing-retracted position, passing the proximal convex portion 751 proximally, and moving to a position proximal to the proximal convex portion 751 (see FIG. 15B ). Thus, after being moved to the pushing-retracted position by the proximal convex portion 751, the pushing portion 85 is located proximal to the proximal convex portion 751 and then reaches the pushing-deployed position.

[0171] When the second shaft 8 moves toward the base end relative to the first shaft 7 due to the biasing force of the biasing member 4 to change from the state immediately after the first discharge to the state immediately before the second discharge, the restricting guided portion 832 moves while being guided by the protruding portion 752 on the tip end side (see FIG. 14A ). During this movement, the discharge guided portion 870 moves while being guided by the protruding portion 752 on the tip end side. Furthermore, during this movement, the protruding guided portion 890 moves while being guided by the protruding portion 751 on the base end side.

[0172] Furthermore, during this movement, the restricting portion 83 is prevented from opening radially outward, and the pushing portion 85 is prevented from opening radially outward (see FIG. 13B).

[0173] Immediately before the second discharge, the restricting and locked portion 82 of the restricting portion 83 of the second shaft portion 8 is locked by the biasing force of the biasing member 4 to the restricting and locked portion 76 of the protruding portion 751 on the base end side of the first shaft portion 7 (see FIG. 14B ). Specifically, the base end surface 820 of the restricting and locked portion 82 of the restricting portion 83 is locked to the distal end surface 7511 of the protruding portion 751 on the base end side. This locking restricts movement of the second shaft portion 8 relative to the first shaft portion 7.

[0174] When the user of syringe 1 pushes second shaft portion 8 (specifically, second base end portion 81) toward the tip from a state immediately before the second ejection, as shown in Figures 15A and 15B, first shaft portion 7 is pushed toward the tip together with second shaft portion 8, and the second ejection of medicinal liquid is performed.

[0175] The second liquid medicine ejection is completed when the piston 30 provided at the first tip portion 72 of the first shaft portion 7 hits the inner surface of the tip portion of the main body connecting portion 222 of the barrel main body 22.

[0176] Hereinafter, a configuration in which first shaft portion 7 and second shaft portion 8 have an axisymmetric shape and syringe 1 administers a drug solution in three divided doses will be described with reference to FIGS. 16 to 23C.

[0177] 16 and 17A , in this embodiment, the finger grip 23 also includes a grip proximal extension 234 as an ejection completion locking portion 24 that locks with the plunger 3 upon completion of the first and second ejections of the syringe 1. A proximal end surface 240 of the ejection completion locking portion 24 is configured as a proximal end surface 2340 that is the surface of the grip proximal extension 234 facing the proximal end.

[0178] 17C , in addition to a first main shaft portion 70, a first base end portion 71, and a first tip end portion 72, first shank portion 7 includes a plurality of protrusions 75 provided on one side and the other side of first main shaft portion 70. Five pairs of protrusions 75 are provided on first main shaft portion 70, sandwiching slits 700 and 701 between them, spaced apart in the axial direction. The axial dimensions of the first and second protrusions 751 and 752 from the base end among protrusions 75 are smaller than the third, fourth, and fifth protrusions 753, 754, and 755 from the base end.

[0179] The protrusions 75 each guide the axial movement of the second shaft portion 8 relative to the first shaft portion 7 when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4. Furthermore, the protrusions 75 restrict the circumferential movement of the second shaft portion 8 while the movement of the second shaft portion 8 relative to the first shaft portion 7 is restricted by the biasing force of the biasing member 4. The guide surfaces 7510, 7520, 7530, 7540, and 7550 of the protrusions 751, 752, 753, 754, and 755 facing the slits 700 and 701 abut against a portion of the second shaft portion 8, thereby guiding the axial movement of the second shaft portion 8 and restricting the circumferential movement of the second shaft portion 8. The guide surfaces 7510, 7520, 7530, 7540, and 7550 of the protrusions 75 are flat surfaces.

[0180] The third, fourth, and fifth protrusions 753, 754, and 755 from the base end in the axial direction of the protrusions 75 include a restricting locking portion 76 that restricts movement of the second shank 8 relative to the first shank 7 due to the biasing force of the biasing member 4. In this embodiment, the distal end of each of the protrusions 753, 754, and 755 constitutes the restricting locking portion 76. The distal end surfaces 7531, 7541, and 7551 of the protrusions 753, 754, and 755, which face the distal end, constitute a distal end surface 760 of the restricting locking portion 76 (see FIGS. 18C, 20C, and 22C). The distal end surface 760 of the restricting locking portion 76 abuts a portion of the second shank 8, thereby restricting movement of the second shank 8 relative to the first shank 7 due to the biasing force. The distal end surface 760 is a flat surface.

[0181] A plurality of restricting locking portions 76 are provided at intervals in the axial direction, and in this embodiment, three sets are provided (see FIG. 17C ). Specifically, the restricting locking portions 76 are configured as three sets of spindle restricting locking portions 76 lined up in the axial direction of the first main shaft portion 70 so as to be spaced apart in the axial direction. In this embodiment, the restricting locking portions 76 are provided in three sets at axial intervals at positions 180° apart in the circumferential direction of the first shaft portion 70.

[0182] The first and second protrusions 751, 752 from the proximal end include push-in locking portions 77 that lock the second shank 8 when the plunger 3 is pushed into the barrel 2. Two sets of push-in locking portions 77 are provided in the axial direction. In this embodiment, the proximal ends of the protrusions 751, 752 constitute the push-in locking portions 77. The proximal end surfaces 7512, 7522 of the protrusions 751, 752 facing the proximal ends constitute the proximal end surfaces 770 of the push-in locking portions 77 ( FIGS. 21C and 23C ). The proximal end surfaces 770 of the push-in locking portions 77 contact a portion of the second shank 8, thereby restricting axial movement of the second shank 8 toward the distal end relative to the first shank 7 and enabling the plunger 3 to be pushed into the barrel 2. The proximal end surfaces 770 of the push-in locking portions 77 are flat.

[0183] Two sets of push-in locking portions 77 are provided on both sides of the central axis of the first main shaft portion 70, spaced apart in the axial direction (see FIG. 17C ). Specifically, two sets of push-in locking portions 77 are provided on both sides of the central axis of the first main shaft portion 70, spaced apart in the axial direction, at positions 180° apart in the circumferential direction of the first main shaft portion 70. In this embodiment, the push-in locking portions 77 are provided on both sides of the central axis of the first main shaft portion 70, and are composed of two sets of main shaft push-in locking portions 77 lined up in the axial direction.

[0184] In addition, in this syringe 1, the first base end portion 71 forms a push-in locking portion 77 that locks onto a part of the second base end portion 81 during the first ejection of the liquid medicine.

[0185] The first and second protrusions 751, 752 from the base end comprise the pushing guide portion 6. The distal end of each of the protrusions 751, 752 constitutes the pushing guide portion 6. Distal end surfaces 7511, 7521, which are the surfaces of the protrusions 751, 752 facing the distal end, constitute the distal end surface 600 of the pushing guide portion 6 (see FIGS. 19C and 21C ). The pushing guide portion 6 guides a portion of the second shaft portion 8 from the pushing and deployed position to the pushing and retracted position as the distal end surface 600 of the pushing guide portion 6 abuts against a portion of the second shaft portion 8.

[0186] Two sets of pushing guide portions 6 are provided at an axial distance apart on both sides of the central axis of first main shaft portion 70. Specifically, two sets of pushing guide portions 6 are provided at positions 180° apart in the circumferential direction of first main shaft portion 70, with an axial distance between them. In this embodiment, the pushing guide portions 6 are configured by two sets of main shaft pushing guide portions 6 arranged side by side at an axial distance between them on both sides of the central axis of first main shaft portion 70.

[0187] 17B , in addition to the second main shaft portion 80 and the second base end portion 81, the second shank 8 also includes a restricting portion 83 having a starting end 830 at the distal end and a free end 831 at the proximal end. The restricting portion 83 is configured to be rotatable around the starting end 830 between a restricted retracted position where the free end 831 is located radially inward and a restricted deployed position where the free end 831 is located radially outward. The second shank 8 also includes a pushing portion 85 having a pushed-in locked portion 84 that locks with the pushed-in locking portion 77 of the first shank 7 when the plunger 3 is pushed in. The second shank 8 also includes a discharge completion portion 87 having a discharge completion locked portion 86 that locks with the discharge completion locking portion 24 when the discharge of the medicinal liquid is completed, and protrusions 891 and 892.

[0188] In this second shaft portion 8, the restricting portions 83 are provided in pairs at positions facing each other across the circumferential central axis of the second main shaft portion 80. Similarly, the pushing portion 85, the discharge completion portion 87, and the protruding portions 891 and 892 are provided in pairs at positions facing each other across the circumferential central axis of the second main shaft portion 80. In addition, in this second shaft portion 8, the protruding portion 891, the pushing portion 85, the protruding portion 892, the discharge completion portion 87, and the restricting portion 83 are arranged in this order from the base end side to the tip end side in the axial direction.

[0189] In this embodiment, the second main shaft portion 80 includes a second main wall portion 800 having a generally rectangular plate shape extending along the axial direction, and a second sub-wall portion 801 extending perpendicular to the second main wall portion 800 at the center of the width direction of the second main wall portion 800. The second main wall portion 800 has a shape in which a radially outer end portion is partially cut out, and the remaining portion forms a protrusion 891, a pushing portion 85, a protrusion 892, a discharge completion portion 87, and a restricting portion 83. The second sub-wall portion 801 fits onto the first shaft portion 7. This fit restricts circumferential movement of the second shaft portion 8 while restricting movement of the second shaft portion 8 relative to the first shaft portion 7 due to the biasing force of the biasing member 4. This fit also restricts circumferential movement of the second shaft portion 8 when the plunger 3 is pushed in or when the second shank 8 moves axially relative to the first shank 7 due to the biasing force.

[0190] The restricting portion 83 has a restricting locked portion 82 at its free end 831 that is locked to the restricting locking portion 76 of the first shaft portion 7 by the biasing force of the biasing member 4 when in the restricting deployed position. The restricting portion 83 is also provided on the second main shaft portion 80. A base end of the restricting portion 83 constitutes the restricting locked portion 82. When the restricting portion 83 is in the restricting deployed position, the restricting locked portion 82 is locked to the restricting locking portion 76 (see FIGS. 18C, 20C, and 22C). When the restricting portion 83 is in the restricting retracted position, the restricting locked portion 82 is not locked to the restricting locking portion 76.

[0191] In this embodiment, a pair of restricting and locked portions 82 are provided on either side of the central axis of the second main shaft portion 80 (see FIG. 17B ). The surface of the restricting portion 83 facing the base end, specifically, the base end surface 820 of the restricting and locked portion 82, abuts against the distal end surface 760 of the restricting and locked portion 76 of the first shaft portion 7, thereby restricting movement of the second shaft portion 8 relative to the first shaft portion 7 due to the biasing force (see FIGS. 18C , 20C , and 22C ). The base end surface 820 of the restricting and locked portion 82 is a flat surface.

[0192] The restricting portion 83 includes a restricting guided portion 832 provided between the pair of restricting locked portions 82 (see FIG. 17B ). The restricting portion 83 also includes a restricting extension portion 833 that extends from the radially inner end of the restricting locked portion 82 further toward the base end.

[0193] The regulated guided portion 832 is a portion for guiding the movement of the second shaft portion 8 along the axial direction relative to the first shaft portion 7 when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4.

[0194] In the present embodiment, the restricted guided portion 832 comes into contact with the convex portions 754, 755 of the first shaft portion 7, thereby guiding the movement of the second shaft portion 8 along the axial direction. Specifically, the outer surface 8320 of the restricted guided portion 832 facing the circumferential direction of the second shaft portion 8 comes into contact with the guide surfaces 7540, 7550 of the convex portions 754, 755 facing the slits 700, 701, thereby guiding the movement of the second shaft portion 8 along the axial direction. The outer surface 8320 of the restricted guided portion 832 is a flat surface.

[0195] The restricting extension 833 is a stopper that prevents the restricting portion 83 from opening radially outward when the second shaft 8 moves relative to the first shaft 7 due to the biasing force of the biasing member 4, and when the movement of the second shaft 8 relative to the first shaft 7 is restricted. The restricting extension 833 is also located radially inward of a portion of the discharge completion portion 87. In this embodiment, the restricting extension 833 is a rib that extends axially from the radially inner end of the restricting locked portion 82 toward the base end. An outer surface 8330 located radially outward of the restricting extension 833 is a flat surface (see FIGS. 19B and 21B ).

[0196] The pushing portion 85 has a starting end 850 on the base end side and a free end 851 on the tip end side, and is configured to be rotatable around the starting end 850 between a pushing retracted position where the free end 851 is located radially inward and a pushing deployed position where the free end 851 is located radially outward (see FIG. 17B ). In this embodiment, the tip end of the pushing portion 85 constitutes the pushing locked portion 84. The pushing locked portion 84 is a spindle pushing locked portion 84 provided at the free end 851 of the pushing portion 85, and is configured as the spindle pushing locked portion 84 that locks with the spindle pushing locked portion 77 of the first shaft portion 7 when pushed in at the pushing deployed position.

[0197] A pair of push-in locked portions 84 are provided on both sides of the central axis of second main shaft portion 80. When plunger 3 is pushed in, the surface of push-in portion 85 facing the tip, specifically, the tip surface 840 of push-in locked portion 84, comes into contact with the base end surface 770 of push-in locked portion 77 of first shank 7, and a force moving the second shank 8 toward the tip is transmitted to first shank 7, causing the first shank 7 to move together with the second shank 8 (see FIGS. 21C and 23C ). Tip surface 840 of push-in locked portion 84 is a flat surface.

[0198] Furthermore, the base end surface 841 of the pressed-in interlocking portion 84, which faces the base end, is an inclined surface that is positioned radially inward as it approaches the base end. When the second shank 8 moves toward the base end relative to the first shank 7 due to the biasing force of the biasing member 4, the base end surface 841 of the pressed-in interlocking portion 84 abuts against the tip end surfaces 7511 and 7521 of the first and second protrusions 751 and 752 from the base end of the first shank 7, causing the pressing portion 85 to move from the pressed-in deployed position to the pressed-in retracted position (see FIGS. 19C and 21C ). The base end surface 841 of the pressed-in interlocking portion 84 is a flat surface.

[0199] The pushing portion 85 includes a pushing extension portion 853 that extends from the radially inner end of the pushing engagement portion 84 toward the tip side (see FIG. 17B).

[0200] The push-in extension 853 is a stopper that prevents the push-in portion 85 from opening radially outward when the second shank 8 is moved toward the tip by the user of the syringe 1 as the second shank 8 is moved relative to the first shank 7 by the biasing force of the biasing member 4. In this embodiment, the push-in extension 853 is a rib that extends axially from the radially inner end of the push-in engagement portion 84 toward the tip. The push-in extension 853 is also located radially inward of a portion of the discharge completion portion 87. An outer surface 8530 located radially outward of the push-in extension 853 is a flat surface (see FIGS. 19B and 21B ).

[0201] Discharge completion portion 87 is a stopper that engages with discharge completion locking portion 24 of barrel 2 to restrict plunger 3 that has moved a distance corresponding to one discharge. In this embodiment, discharge completion portion 87 engages with discharge completion locking portion 24 upon completion of the first and second discharges of the medicinal liquid. Discharge completion portion 87 is also provided on second main shaft portion 80.

[0202] In this embodiment, the tip of ejection completion portion 87 constitutes ejection completion locked portion 86. A pair of ejection completion locked portions 86 are provided on either side of the central axis of second main shaft portion 80. Furthermore, when tip surface 860 of ejection completion locked portion 86 abuts against base end surface 240 of ejection completion locking portion 24 of barrel 2, movement of second shaft portion 8 toward the tip side by the user of syringe 1, i.e., one ejection of medicinal liquid, is completed. Tip surface 860 of ejection completion locked portion 86 is a flat surface.

[0203] The discharge completion portion 87 includes a discharge guided portion 870 that is the radially outer end (see FIG. 17B). The discharge completion portion 87 also includes a discharge extension portion 871 that extends as the end on the tip side of the discharge guided portion 870.

[0204] The discharge guided portion 870 is a portion for guiding the movement of the second shaft portion 8 along the axial direction relative to the first shaft portion 7 when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4. The discharge guided portion 870 is also a portion for restricting the circumferential movement of the second shaft portion 8 in a state in which the movement of the second shaft portion 8 relative to the first shaft portion is restricted by the biasing force of the biasing member 4.

[0205] In the present embodiment, the discharge guided portion 870 comes into contact with the convex portions 753, 754 of the first shaft portion 7, thereby guiding the movement of the second shaft portion 8 along the axial direction and restricting the movement of the second shaft portion 8 in the circumferential direction. Specifically, the outer surface 8700 of the discharge guided portion 870 facing the circumferential direction of the second shaft portion 8 comes into contact with the guide surfaces 7530, 7540 of the convex portions 753, 754 facing the slits 700, 701, thereby guiding the movement of the second shaft portion 8 along the axial direction and restricting the movement of the second shaft portion 8 in the circumferential direction. The outer surface 8700 of the discharge guided portion 870 is a flat surface.

[0206] The discharge extension portion 871 is a stopper pressing portion that presses the restricting extension portion 833 of the restricting portion 83 to prevent the restricting portion 83 from opening radially outward when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4 and when the movement of the second shaft portion 8 relative to the first shaft portion 7 is restricted. The discharge extension portion 871 is located radially outward of the restricting extension portion 833. In this embodiment, the discharge extension portion 871 is a rib that extends axially toward the tip end of the discharge guided portion 870. The inner surface 8710 on the radially inner side of the discharge extension portion 871 is a flat surface. The inner surface 8710 of the discharge extension portion 871 abuts against the radially outer outer surface 8330 of the restricting extension portion 833, thereby preventing the restricting portion 83 from opening radially outward (see FIGS. 19B and 21B ).

[0207] The protruding portion 891 has a protruding guided portion 8910 which is the radially outer end portion (see FIG. 17B).

[0208] The protruding guided portion 8910 is a portion for guiding the movement of the second shaft portion 8 along the axial direction relative to the first shaft portion 7 when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4. The protruding guided portion 8910 is also a portion for restricting the circumferential movement of the second shaft portion 8 in a state in which the movement of the second shaft portion 8 relative to the first shaft portion is restricted by the biasing force of the biasing member 4.

[0209] In the present embodiment, the protruding guided portion 8910 abuts against the convex portion 751 located closest to the base end of the first shaft portion 7, thereby guiding the movement of the second shaft portion 8 along the axial direction and restricting the movement of the second shaft portion 8 in the circumferential direction. Specifically, the outer surface 8911 of the protruding guided portion 8910 facing the circumferential direction of the second shaft portion 8 abuts against the guide surface 7510 of the convex portion 751 facing the slits 700, 701, thereby guiding the movement of the second shaft portion 8 along the axial direction and restricting the movement of the second shaft portion 8 in the circumferential direction. The outer surface 8911 of the protruding guided portion 8910 is a flat surface.

[0210] The protruding portion 892 includes a protruding guided portion 8920 that is the radially outer end portion. The protruding portion 892 also includes a protruding extension portion 8921 that extends as the end portion on the tip side of the protruding guided portion 8920.

[0211] The protruding guided portion 8920 is a portion for guiding the movement of the second shaft portion 8 along the axial direction relative to the first shaft portion 7 when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4. The protruding guided portion 8920 is also a portion for restricting the circumferential movement of the second shaft portion 8 in a state in which the movement of the second shaft portion 8 relative to the first shaft portion is restricted by the biasing force of the biasing member 4.

[0212] In the present embodiment, the protruding guided portion 8920 abuts against the second and third convex portions 752, 753 from the base end side of the first shaft portion 7, thereby guiding movement of the second shaft portion 8 along the axial direction and restricting movement of the second shaft portion 8 in the circumferential direction. Specifically, an outer surface 8922 of the protruding guided portion 8920 facing the circumferential direction of the second shaft portion 8 abuts against the guide surfaces 7520, 7530 facing the one-side slit 700 side of the convex portions 752, 753, thereby guiding movement of the second shaft portion 8 along the axial direction and restricting movement of the second shaft portion 8 in the circumferential direction. The outer surface 8922 of the protruding guided portion 8920 is a flat surface.

[0213] The protruding extension 8921 is a stopper pressing portion that presses the pushing extension 853 of the pushing portion 85 to prevent the pushing portion 85 from opening radially outward when the second shank 8 moves relative to the first shank 7 due to the biasing force of the biasing member 4, and when the user of the syringe 1 moves the second shank 8 toward the distal end. The protruding extension 8921 is located radially outward of the pushing extension 853. In this embodiment, the protruding extension 8921 is a rib that extends axially toward the proximal end as the proximal end of the protruding portion 892. The inner surface 8923 of the protruding extension 8921 on the radially inner side is a flat surface. The inner surface 8923 of the protruding extension 8921 abuts against the radially outer outer surface 8530 of the pushing extension 853, thereby preventing the pushing portion 85 from opening radially outward (see FIGS. 19B and 21B ).

[0214] In this syringe 1, during the first ejection of the liquid medicine, the second base end 81 of the second shaft 8 forms a pushed-in locked portion 84 that locks onto the first base end 71 of the first shaft 7.

[0215] When one push is completed, the deregulating portion 5 moves the restricting portion 83 from the restricting deployed position to the restricting retracted position, thereby releasing the restricting locked portion 82 from the restricting locking portion 76. In this embodiment, the deregulating portion 5 is configured by the radially inner end portion 2321 of the main body base end portion 232 of the grip main body 230.

[0216] The operations and states when using the syringe 1 will be described in detail below.

[0217] As shown in FIGS. 16 and 18A , the initial state is a state in which the syringe 1 has not yet dispensed any liquid medicine. In the initial state, the second shank 8 is biased proximally relative to the first shank 7 by the biasing force of the biasing member 4, and the restricting portion 83 is in the restricted deployed position (see FIG. 18B ). Furthermore, the restricting interlocked portion 82 of the restricting portion 83 is interlocked with the restricting interlocking portion 76 of the fifth protrusion 755 from the proximal end of the first shank 7 by the biasing force of the biasing member 4 (see FIG. 18C ). Specifically, the proximal end surface 820 of the restricting interlocked portion 82 of the restricting portion 83 is interlocked with the distal end surface 7551 of the fifth protrusion 755 from the proximal end. This interlocking restricts movement of the second shank 8 relative to the first shank 7.

[0218] When the user of syringe 1 pushes second base end 81 toward the tip from the initial state, first shaft portion 7 is pushed toward the tip together with second shaft portion 8, as shown in Figures 19A and 19B, and the first ejection of medicinal liquid is performed.

[0219] The first ejection of liquid medicine is completed when ejection completion locked portion 86 of ejection completion section 87 is locked with ejection completion locking portion 24 of barrel 2. Specifically, the first ejection of liquid medicine is completed when distal end surface 860 of ejection completion locked portion 86 is locked with proximal end surface 240 of ejection completion locking portion 24 (see FIG. 19B ).

[0220] During the first ejection of the liquid medicine, the restricting portion 83 of the second shaft 8 is moved from the extended restricting position to the retracted restricting position by the derestricting portion 5. Specifically, the radially outer end surface 8321 of the restricting portion 83 abuts against the radially inner end 2321 of the main body base end 232 of the finger grip 23, causing the restricting portion 83 to bend and move from the extended restricting position to the retracted restricting position. This also causes the restricted locked portion 82 of the second shaft 8 to move radially inward, releasing the lock of the restricted locked portion 82 with the restricted locking portion 76 of the first shaft 7. The biasing force of the biasing member 4 then causes the second shaft 8 to move proximally relative to the first shaft 7, resulting in the state immediately before the second ejection shown in FIGS. 20A to 20C .

[0221] Furthermore, during the first ejection, the restricting portion 83 is moved to the restricting retracted position by the restricting release portion 5, and then moves to the restricting deployed position between the restricting locking portion 76 of the fifth protrusion 735 from the base end of the first shaft portion 7, which was locked in the initial state, and the restricting locking portion 76 of the fourth protrusion 754 from the base end (see Figures 19C and 20C).

[0222] Furthermore, immediately after the first discharge, the pushing portion 85 of the second shank 8 is located distally of the second protruding portion 752 from the proximal end (see FIG. 19C ). When the second shank 8 moves proximally relative to the first shank 7 due to the biasing force of the biasing member 4 and reaches a state immediately before the second discharge, the proximal end surface 841 of the pushing-engaged portion 84 of the pushing portion 85 abuts the distal end surface 7521 of the second protruding portion 752 from the proximal end. As a result, the pushing portion 85 is pushed radially inward to the pushing retracted position, passes the second protruding portion 752 from the proximal end toward the proximal end, and moves between the first protruding portion 751 from the proximal end and the second protruding portion 752 from the proximal end (see FIG. 20C ). In this way, the pushing portion 85 is moved to the pushing retraction position by the tip surface 7521 of the second protrusion 752 from the base end side, and then reaches the pushing deployment position at a position closer to the base end than the second protrusion 752 from the base end side.

[0223] When the second shaft 8 moves toward the base end relative to the first shaft 7 due to the biasing force of the biasing member 4 so as to change from the state immediately after the first ejection to the state immediately before the second ejection, the restricted guided portion 832 moves while being guided by the fifth convex portion 755 from the base end. During this movement, the protruding guided portion 8920 moves while being guided by the third convex portion 753 from the base end.

[0224] Furthermore, during this movement, the restricting portion 83 is prevented from opening radially outward, and the pushing portion 85 is prevented from opening radially outward (see FIG. 19B).

[0225] Immediately before the second discharge, the restricting and locked portion 82 of the restricting portion 83 of the second shank 8 is locked by the biasing force of the biasing member 4 to the restricting and locked portion 76 of the fourth protrusion 754 from the base end of the first shank 7 (see FIG. 20C ). Specifically, the base end surface 820 of the restricting and locked portion 82 of the restricting portion 83 is locked to the distal end surface 7541 of the fourth protrusion 754 from the base end. This locking restricts movement of the second shank 8 relative to the first shank 7.

[0226] When the user of syringe 1 pushes second base end 81 toward the distal end from the state immediately before the second ejection (see FIGS. 20A to 20C), as shown in FIGS. 21A to 21C, distal end surface 840 of push-in locked portion 84 abuts against proximal end surface 770 of push-in locking portion 77 of first shank 7, and the first shank 7 is pushed toward the distal end together with second shank 8, thereby ejecting the second liquid medicine. Specifically, distal end surface 840 abuts against proximal end surface 7522 of second protrusion 752 from the proximal end (see FIG. 21C).

[0227] The second discharge of liquid medicine is completed when the distal end surface 860 of the discharge completion locking portion 86 locks with the proximal end surface 240 of the discharge completion locking portion 24 (see FIG. 21B ). During the second discharge of liquid medicine, the restricting portion 83 of the second shank 8 is deflected by the radially outer end surface 8321 of the restricting portion 83 contacting the radially inner end portion 2321 of the main body proximal end 232 of the finger grip 23, and is moved from the extended restricting position to the retracted restricting position. This causes the restricting locked portion 82 of the second shank 8 to also move radially inward, releasing the lock of the restricting locked portion 82 with the restricting locking portion 76 of the first shank 7. This causes the biasing force of the biasing member 4 to move the second shank 8 toward the proximal end relative to the first shank 7, resulting in the state immediately before the third discharge shown in FIGS. 22A to 22C .

[0228] Also, during the second ejection, the restricting portion 83 is moved to the restricting retracted position by the restricting release portion 5, and then moves to the deployed position between the restricting locking portion 76 of the fourth protrusion 754 from the base end of the first shaft portion 7, which was engaged immediately before the second ejection, and the restricting locking portion 76 of the third protrusion 753 from the base end (see Figures 21C and 22C).

[0229] Furthermore, just before the third discharge, the base end surface 841 of the push-in locked portion 84 of the pushing portion 85 comes into contact with the tip end surface 7511 of the protruding portion 751 located at the base end side of the first shaft portion 7. As a result, the pushing portion 85 is pushed radially inward to the push-in retracted position, passes through the protruding portion 751 at the base end side, and moves to the base end side of the protruding portion 751 located at the base end side.

[0230] When the second shaft 8 moves toward the proximal end relative to the first shaft 7 due to the biasing force of the biasing member 4 to move from the state immediately after the second discharge to the state immediately before the third discharge, the restricting guided portion 832 is guided by the fourth protruding portion 754 from the proximal end, and the second shaft 8 moves along the axial direction (see FIGS. 17B and 21A ). During this movement, the discharge guided portion 870 is guided by the third protruding portion 753 from the proximal end, and the second shaft 8 moves along the axial direction. During this movement, the protruding guided portion 8910 is guided by the proximal-most protruding portion 751, and the second shaft 8 moves along the axial direction. During this movement, the protruding guided portion 8920 is guided by the second protruding portion 752 from the proximal end, and the second shaft 8 moves along the axial direction.

[0231] Furthermore, during this movement, the restricting portion 83 is prevented from opening radially outward, and the pushing portion 85 is prevented from opening radially outward (see FIG. 21B).

[0232] Immediately before the third ejection, the restricting and locked portion 82 of the restricting portion 83 of the second shank 8 is locked by the biasing force of the biasing member 4 to the restricting and locked portion 76 of the third protrusion 753 from the base end of the first shank 7 (see FIG. 22C ). Specifically, the base end surface 820 of the restricting and locked portion 82 of the restricting portion 83 is locked to the distal end surface 7531 of the third protrusion 753 from the base end. This locking restricts movement of the second shank 8 relative to the first shank 7.

[0233] When the user of syringe 1 pushes second base end 81 toward the tip from the state immediately before the third ejection (see Figures 22A to 22C), as shown in Figures 23A to 23C, the tip surface 840 of push-in interlocking portion 84 comes into contact with the base end surface 7512 of convex portion 751 located closest to the base end, and the first shaft portion 7 is pushed toward the tip together with second shaft portion 8, and the third ejection of the medicinal liquid is performed.

[0234] The third ejection of the liquid medicine is completed when the piston 30 provided at the first tip portion 72 of the first shaft portion 7 hits the tip portion of the main body connecting portion 222 of the barrel main body 22.

[0235] 1A to 9B, second shank 8 has restricting portion 83 provided on one circumferential side and pushing portion 85 provided on the other circumferential side, but restricting portion 83 and pushing portion 85 may be provided on one circumferential side. Below, a configuration in which first shank 7 and second shank 8 have an axially asymmetric shape and syringe 1 administers the medicinal liquid in two divided doses will be described using FIGS.

[0236] As shown in Fig. 25D, the first shank 7 includes a first main shank 70, a first base end 71, and a first tip end 72, as well as a plurality of protrusions 75 provided on one side of the first main shank 70. Two sets of protrusions 75 are provided on the first main shank 70 with a gap between them in the axial direction. The first main shank 70 also includes a pair of protrusions 75, one of which sandwiches a slit 700 on one side. The protrusions 75 all have the same protrusion size relative to the slit 700. The protrusion 751 provided on the base end side has a larger axial dimension than the protrusion 752 provided on the tip end side.

[0237] The two sets of protrusions 75 each guide the axial movement of the second shaft portion 8 relative to the first shaft portion 7 when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4. Furthermore, the two sets of protrusions 75 restrict the circumferential movement of the second shaft portion 8 while the movement of the second shaft portion 8 relative to the first shaft portion 7 is restricted by the biasing force of the biasing member 4. Each of the protrusions 751, 752 has guide surfaces 7510, 7520 facing the slit 700 that abut against a part of the second shaft portion 8, thereby guiding the axial movement of the second shaft portion 8 and restricting the circumferential movement of the second shaft portion 8. The guide surfaces 7510, 7520 of the protrusions 751, 752 are flat surfaces.

[0238] The protrusions 751, 752 include restricting locking portions 76 that restrict movement of the second shaft portion 8 relative to the first shaft portion 7 due to the biasing force of the biasing member 4. In this embodiment, the tip of each of the protrusions 751, 752 constitutes the restricting locking portion 76. Tip surfaces 7511, 7521, which are surfaces facing the tip of the protrusions 751, 752, constitute a tip surface 760 of the restricting locking portion 76 (see Figures 26B and 28B). The tip surface 760 of the restricting locking portion 76 abuts a part of the second shaft portion 8, thereby restricting movement of the second shaft portion 8 relative to the first shaft portion 7 due to the biasing force. The tip surface 760 is a flat surface. Two sets of restricting locking portions 76 are provided spaced apart in the axial direction.

[0239] The protrusion 751 located on the base end side includes a push-in locking portion 77 that locks with the second shank 8 when the plunger 3 is pushed into the barrel 2 (see FIG. 25D ). A set of push-in locking portions 77 is provided. In this embodiment, the base end of the protrusion 751 constitutes the push-in locking portion 77. A base end surface 7512, which is the surface of the protrusion 751 facing the base end, constitutes a base end surface 770 of the push-in locking portion 77. The base end surface 770 of the push-in locking portion 77 abuts a part of the second shank 8, thereby restricting movement of the second shank 8 toward the axial tip side relative to the first shank 7 and enabling the plunger 3 to be pushed into the barrel 2. The base end surface 770 of the push-in locking portion 77 is a flat surface.

[0240] There is provided a set of push-in locking portions 77. In this embodiment, the push-in locking portions 77 are configured by a set of main shaft push-in locking portions 77.

[0241] In this embodiment, the protruding portion 751 located on the base end side includes a pushing guide portion 6 that guides a portion of the second shaft portion 8 from the pushing deployment position to the pushing retract position. The tip of the protruding portion 751 constitutes the pushing guide portion 6. The tip surface 7511 of the protruding portion 751 facing the tip constitutes the tip surface 600 of the pushing guide portion 6 (see FIG. 28B ). The pushing guide portion 6 guides a portion of the second shaft portion 8 from the pushing deployment position to the pushing retract position when the tip surface 600 of the pushing guide portion 6 abuts against a portion of the second shaft portion 8. The pushing guide portion 6 is composed of a set of main shaft pushing guide portions 6 provided on the first main shaft portion 70.

[0242] In addition, in this syringe 1, the first base end portion 71 forms a push-in locking portion 77 that locks onto a part of the second base end portion 81 during the first ejection of the liquid medicine.

[0243] In this embodiment, as shown in FIG. 25C , second shaft 8 includes restricting portion 83 configured to be rotatable about starting end 830, and pushing portion 85 including pushed-in locked portion 84. Second shaft 8 also includes ejection completion portion 87 including ejection completion locked portion 86, and protruding portion 893. On one side of second main shaft 80, pushing portion 85, protruding portion 893, and restricting portion 83 are arranged in this order from the base end toward the tip end in the axial direction. On the other side of second main shaft 80, ejection completion portion 87 is provided. Second main shaft 80 also includes recess 90 into which restricting portion 83 is accommodated when in the pushed-in retracted position, and recess 91 into which pushing portion 85 is accommodated when in the pushed-in retracted position.

[0244] The restricting portion 83 includes a pair of restricting and locked portions 82 arranged in the circumferential direction, a restricting and guided portion 832, and a restricting extension portion 833.

[0245] In the present embodiment, the restricted guided portion 832 abuts against the convex portion 752 on the tip side of the first shaft portion 7, thereby guiding the movement of the second shaft portion 8 along the axial direction and restricting the movement of the second shaft portion 8 in the circumferential direction. Specifically, the outer surface 8320 of the restricted guided portion 832 facing the circumferential direction of the second shaft portion 8 abuts against the guide surface 7520 of the convex portion 752 facing the one-side slit 700, thereby guiding the movement of the second shaft portion 8 along the axial direction and restricting the movement of the second shaft portion 8 in the circumferential direction. The outer surface 8320 of the restricted guided portion 832 is a flat surface.

[0246] The restricting extension 833 is a stopper that prevents the restricting portion 83 from opening radially outward when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4, and when the movement of the second shaft portion 8 relative to the first shaft portion 7 is restricted. The restricting extension 833 is located radially inward of a portion of the protrusion 893. In this embodiment, the restricting extension 833 is a rib that extends axially from the radially inner end of the restricting locked portion 82 toward the base end. An outer surface 8330 located radially outward of the restricting extension 833 is a flat surface.

[0247] The pushing portion 85 has a starting end 850 on the base end side and a free end 851 on the tip end side, and is configured to be rotatable around the starting end 850 between a pushing retracted position where the free end 851 is located on the radially inner side and a pushing deployed position where it is located on the radially outer side.

[0248] In this embodiment, the tip of the pushing portion 85 constitutes the push-in locked portion 84. The push-in locked portion 84 is a main shaft push-in locked portion 84 provided at a free end 851 of the pushing portion 85, and is configured as a main shaft push-in locked portion 84 that locks with the main shaft push-in locked portion 77 of the first shank 7 when pushed in the push-in deployed position (see FIG. 29B ). One push-in locked portion 84 is provided on the pushing portion 85. When the plunger 3 is pushed in, the surface facing the tip of the pushing portion 85, specifically the tip surface 840 of the push-in locked portion 84, hits the base end surface 770 of the push-in locked portion 77 of the first shank 7, thereby transmitting a force to move the second shank 8 toward the tip side to the first shank 7, and the first shank 7 moves together with the second shank 8. The tip surface 840 of the push-in locked portion 84 is a flat surface.

[0249] Furthermore, the base end surface 841 of the pressed-in interlocked portion 84, which faces the base end, is an inclined surface that is positioned radially inward as it approaches the base end (see FIG. 27C ). When the second shank 8 moves toward the base end relative to the first shank 7 due to the biasing force of the biasing member 4, the base end surface 841 of the pressed-in interlocked portion 84 comes into contact with the tip end surface 7511, which is the surface facing the tip end of the protruding portion 751 on the base end of the first shank 7, and the pressed-in portion 85 moves from the pressed-in deployed position to the pressed-in retracted position. The base end surface 841 of the pressed-in interlocked portion 84 is a flat surface.

[0250] In this syringe 1, the second base end portion 81 forms a pushed-in locked portion 84 that locks onto the first base end portion 71 during the first ejection of the liquid medicine.

[0251] The pushing portion 85 includes a pushing extension portion 853 that extends from the radially inner end of the pushing engagement portion 84 toward the tip side (see FIGS. 25B and 25C).

[0252] The push-in extension 853 is a stopper that prevents the push-in portion 85 from opening radially outward when the second shank 8 moves relative to the first shank 7 due to the biasing force of the biasing member 4, and when the user of the syringe 1 moves the second shank 8 toward the tip. In this embodiment, the push-in extension 853 is a rib that extends axially from the radially inner end of the push-in locked portion 84 toward the tip. The push-in extension 853 is located radially inward of a portion of the protrusion 893. An outer surface 8530 located radially outward of the push-in extension 853 is a flat surface.

[0253] The ejection completion portion 87 is a stopper that restricts the movement of the plunger 3 by engaging with the ejection completion locking portion 24 of the barrel 2 during the first ejection. In this embodiment, the distal end surface 860 of the ejection completion portion 87 abuts against the proximal end surface 240 of the ejection completion locking portion 24 of the barrel 2, completing the movement of the second shank 8 toward the distal end by the user of the syringe 1, i.e., completing the first ejection of the medicinal liquid (see FIG. 27B ). The distal end surface 860 of the ejection completion locked portion 86 is a flat surface. The ejection completion locking portion 24 is formed by the main body proximal end 232, and the proximal end surface 240 of the ejection completion locking portion 24 is formed by the proximal end surface 2320 of the main body proximal end 232, which is the surface facing the proximal end.

[0254] The discharge completion portion 87 includes a discharge guided portion 870 which is the radially outer end portion (see FIGS. 25B and 25C).

[0255] The discharge guided portion 870 is a portion that guides the movement of the second shaft portion 8 along the axial direction relative to the first shaft portion 7 when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4. The discharge guided portion 870 is also a portion that restricts the circumferential movement of the second shaft portion 8 in a state in which the movement of the second shaft portion 8 relative to the first shaft portion is restricted by the biasing force of the biasing member 4. In this embodiment, an outer surface 8700 of the discharge guided portion 870 facing the circumferential direction of the second shaft portion 8 abuts against a guide surface 702 (see FIG. 25A ) that defines the other-side slit 701 of the first shaft portion 7, thereby guiding the movement of the second shaft portion 8 along the axial direction and restricting the circumferential movement of the second shaft portion 8.

[0256] The protruding portion 893 includes a protruding guided portion 8930 (see FIG. 25C ). The protruding portion 893 also includes a base-end protruding extension portion 8931 extending as an end portion on the base-end side of the protruding guided portion 8930, and a tip-end protruding extension portion 8932 extending as an end portion on the tip-end side of the protruding guided portion 8930.

[0257] The protruding guided portion 8930 is a portion for guiding the movement of the second shaft portion 8 along the axial direction relative to the first shaft portion 7 when the second shaft portion 8 moves relative to the first shaft portion 7 due to the biasing force of the biasing member 4. The protruding guided portion 8930 is also a portion for restricting the circumferential movement of the second shaft portion 8 in a state in which the movement of the second shaft portion 8 relative to the first shaft portion is restricted by the biasing force of the biasing member 4.

[0258] In the present embodiment, the protruding guided portion 8930 comes into contact with the convex portion 752 on the tip side of the first shaft portion 7, thereby guiding the movement of the second shaft portion 8 along the axial direction and restricting the movement of the second shaft portion 8 in the circumferential direction. Specifically, the outer surface 8933 of the protruding guided portion 8930 facing the circumferential direction of the second shaft portion 8 comes into contact with the guide surface 7520 of the convex portion 752 facing the slit 700, thereby guiding the movement of the second shaft portion 8 along the axial direction and restricting the movement of the second shaft portion 8 in the circumferential direction. The outer surface 8933 of the protruding guided portion 8930 is a flat surface.

[0259] The base-side protruding extension portion 8931 is a stopper pressing portion that presses the pushing-in extension portion 853 of the pushing portion 85 to prevent the pushing portion 85 from opening radially outward. The base-side protruding extension portion 8931 is located radially outward of the pushing-in extension portion 853. In this embodiment, the base-side protruding extension portion 8931 is a rib that extends axially toward the base end as the base-side end of the protruding guided portion 8930. An inner surface 8934 on the radially inner side of the base-side protruding extension portion 8931 is a flat surface. The inner surface 8934 of the base-side protruding extension portion 8931 abuts against an outer surface 8530 on the radially outer side of the pushing-in extension portion 853, thereby preventing the pushing portion 85 from opening radially outward (see FIG. 27B ).

[0260] The tip-side protruding extension portion 8932 is a stopper pressing portion that presses the restricting extension portion 833 of the restricting portion 83 to prevent the restricting portion 83 from opening radially outward. The tip-side protruding extension portion 8932 is located radially outward of the restricting extension portion 833. In this embodiment, the tip-side protruding extension portion 8932 is a rib that extends distally along the axial direction as the distal end of the protruding guided portion 8930. An inner surface 8935 on the radially inner side of the tip-side protruding extension portion 8932 is a flat surface. The inner surface 8935 of the tip-side protruding extension portion 8932 abuts against an outer surface 8330 on the radially outer side of the restricting extension portion 833, thereby preventing the restricting portion 83 from opening radially outward.

[0261] The deregulation portion 5 is configured by a radially inner end portion 2321 of the grip body portion 230 of the finger grip 23 , for example, a radially inner end portion 2321 of the body base end portion 232 of the grip body portion 230 .

[0262] The operations and states when using the syringe 1 will be described in detail below.

[0263] 24 and 26A , the initial state is a state in which the syringe 1 has not yet dispensed any liquid medicine. In the initial state, the restricting and locked portion 82 of the restricting portion 83 of the second shank 8 is locked by the biasing force of the biasing member 4 to the restricting and locked portion 76 of the protrusion 752 on the distal end side of the first shank 7. Specifically, the base end surface 820 of the restricting and locked portion 82 of the restricting portion 83 is locked to the distal end surface 7521 of the protrusion 752 on the distal end side (see FIG. 26B ). This locking restricts movement of the second shank 8 relative to the first shank 7.

[0264] When the user of syringe 1 pushes second shank 8 (specifically, second base end 81) toward the tip from the initial state, as shown in Figures 27A to 27C, first shank 7 is pushed toward the tip together with second shank 8, and the first ejection of medicinal liquid is performed.

[0265] The first ejection of liquid medicine is completed when ejection completion locked portion 86 of ejection completion section 87 is locked with ejection completion locking portion 24 of barrel 2 (see FIG. 27B ). Specifically, the first ejection of liquid medicine is completed when distal end surface 860 of ejection completion locked portion 86 is locked with proximal end surface 240 of ejection completion locking portion 24.

[0266] During the first ejection of the liquid medicine, the restricting portion 83 of the second shaft 8 is moved from the extended position to the retracted position by the derestricting portion 5. Specifically, the radially outer end surface 8321 of the restricting portion 83 contacts the radially inner end 2321 of the main body base end 232 of the finger grip 23, causing the restricting portion 83 to bend and move from the extended position to the retracted position. This also causes the restricted locked portion 82 of the second shaft 8 to move radially inward, releasing the lock of the restricted locked portion 82 with the restricted locking portion 76 of the first shaft 7. The biasing force of the biasing member 4 then causes the second shaft 8 to move proximally relative to the first shaft 7, resulting in the state immediately before the second ejection shown in FIGS. 28A and 28B .

[0267] Furthermore, during the first ejection, the restricting portion 83 is moved to the restricting retracted position by the restricting release portion 5, and then moves to the restricting deployed position between the restricting locking portion 76 of the protrusion 752 on the tip side of the first shaft portion 7, which was locked in the initial state, and the restricting locking portion 76 of the protrusion 751 on the base side (see Figures 27C and 28B).

[0268] Furthermore, immediately after the first discharge, the pushing portion 85 of the second shank 8 is located distally of the proximal convex portion 751 (see FIG. 27C ). When the second shank 8 moves proximally relative to the first shank 7 due to the biasing force of the biasing member 4 and reaches a state immediately before the second discharge, the proximal end surface 841 of the pushing-engaged portion 84 of the pushing portion 85 abuts the distal end surface 7511 of the proximal convex portion 751, forcing the pushing portion 85 radially inward to the pushing-retracted position, passing the proximal convex portion 751 proximally, and moving to a position proximal to the proximal convex portion 751 (see FIG. 28B ). Thus, after being moved to the pushing-retracted position by the proximal convex portion 751, the pushing portion 85 is located proximal to the proximal convex portion 751 and then reaches the pushing-deployed position.

[0269] When the second shaft 8 moves toward the base end relative to the first shaft 7 due to the biasing force of the biasing member 4 so as to change from the state immediately after the first discharge to the state immediately before the second discharge, the restricted guided portion 832 moves while being guided by the convex portion 752 on the tip side. During this movement, the discharge guided portion 870 moves while being guided by the guide surface 702 that defines the other-side slit 701 of the first main shaft 70. Also, during this movement, the protruding guided portion 8930 moves while being guided by the convex portion 751 on the tip side. Furthermore, during this movement, the restricting portion 83 and the pushing portion 85 are prevented from opening radially outward (see FIG. 27B ).

[0270] Immediately before the second discharge, the restricting and locked portion 82 of the restricting portion 83 of the second shank 8 is locked by the biasing force of the biasing member 4 to the restricting and locked portion 76 of the protruding portion 751 on the base end side of the first shank 7 (see FIG. 28B ). Specifically, the base end surface 820 of the restricting and locked portion 82 of the restricting portion 83 is locked to the distal end surface 7511 of the protruding portion 751 on the base end side. This locking restricts movement of the second shank 8 relative to the first shank 7.

[0271] When the user of syringe 1 pushes second base end 81 toward the tip from the state immediately before the second ejection, as shown in Figures 29A and 29B, first shaft portion 7 is pushed toward the tip together with second shaft portion 8, and the second ejection of medicinal liquid is performed.

[0272] The second ejection of the liquid medicine is completed when the piston 30 provided at the first tip portion 72 of the first shaft portion 7 hits the tip portion of the main body connecting portion 222 of the barrel main body 22.

[0273] In the above embodiment, the syringe 1 includes the barrel 2, the plunger 3, the biasing member 4, the deregulation portion 5, the pushing guide portion 6, and the discharge nozzle 9. However, it is sufficient if the syringe 1 includes at least the barrel 2, the plunger 3, the biasing member 4, and the deregulation portion 5. For example, the syringe 1 does not need to include at least one of the pushing guide portion 6 and the discharge nozzle 9. If the syringe 1 does not include the discharge nozzle 9, it is possible that the contents (e.g., a medicinal liquid) are discharged from the tip portion 20 of the barrel 2 in a line shape rather than in a mist shape.

[0274] In the above embodiment, the push-in locking portion 77 of the first shaft portion 7 includes a plurality of main shaft push-in locking portions 77 provided on the first main shaft portion 70, but they may be provided at another location on the first shaft portion 7. Furthermore, the push-in portion 85 of the second shaft portion 8 is provided on the second main shaft portion 80, but they may be provided at another location on the second shaft portion 8.

[0275] In the above embodiment, when the user pushes second base end 81 toward the distal end during the discharge of the medicinal liquid except for the first discharge, the first shank 7 is pushed toward the distal end together with second shank 8 with distal end surface 840 of pushed-in interlocking portion 84 abutting against proximal end surface 770 of pushed-in interlocking portion 77 of first shank 7. However, the first shank 7 may be pushed toward the distal end together with second shank 8 with distal end surface 840 of pushed-in interlocking portion 84 abutting against proximal end surface 770 of pushed-in interlocking portion 77 of first shank 7 during all the discharge of the medicinal liquid.

[0276] In the above embodiment, the discharge completion locking portion 24 is provided on the finger grip 23, but it may be provided on a portion other than the finger grip 23. For example, the discharge completion locking portion 24 may be provided on the barrel body 22.

[0277] In the above embodiment, the ejection completion section 87 engages with the ejection completion locking section 24 when the ejection of the medicinal liquid is completed except for the final ejection, but it may also engage with the ejection completion locking section 24 when the ejection of the medicinal liquid is completed at all times.

[0278] 30 to 32, a configuration in which the second shank 8 is provided with ribs to prevent the second shank 8 from wobbling relative to the first shank 7 will be described. As shown in Fig. 32, the second shank 8 has a first rib 92 and a second rib 93. In addition, in this second shank 8, the outer surface 854 of the pushing portion 85 is aligned on the same line in the axial direction as the outer surface 873 of the discharge completion portion 87.

[0279] The first rib 92 is a rib that protrudes radially outward from the second main shaft portion 80, and in this embodiment, extends from the base-end edge of the second main shaft portion 80 along the axial direction toward the tip side, up to just before the restricting portion 83. In other words, the first rib 92 is disposed on the base-end side in the axial direction relative to the restricting portion 83. In this embodiment, the first rib 92 extends continuously between the second base end portion 81 and the protruding portion 88. The protruding dimension of the first rib 92, i.e., the dimension of the first rib 92 in the radial direction, is uniform.

[0280] The first rib 92 passes between the circumferentially adjacent one-side convex portions 73 in the one-side slit 700 of the first shank 7 (see FIG. 30 ). Furthermore, the first rib 92 prevents the second shank 8 from wobbling relative to the first shank 7 by passing between the circumferentially adjacent one-side convex portions 73 in the one-side slit 700 of the first shank 7 from the initial state through the first liquid medicine discharge, the second liquid medicine discharge, and until the discharge of the liquid medicine is completed.

[0281] The second rib 93 is a rib that protrudes radially outward from the second main shaft portion 80. In this embodiment, the second rib 93 extends axially from the base-end edge of the second main shaft portion 80 to the tip side, just before the pressed-in interlocking portion 84 and the discharge completion portion 87 (see FIG. 32 ). The second rib 93 is disposed on the base-end side of the pressed-in interlocking portion 84 and the discharge completion portion 87 in the axial direction. That is, the second rib 93, the pressed-in interlocking portion 84, and the discharge completion portion 87 are aligned in this order from the base end to the tip end in the axial direction. The second rib 93 is continuous with the second base end portion 81. The protruding dimension of the second rib 93, i.e., the radial dimension of the second rib 93, is uniform. The outer surface 930 of the second rib 93 is aligned axially on the same line as the outer surface 854 of the pressed-in portion 85 and the outer surface 873 of the discharge completion portion 87.

[0282] The second rib 93 has a tapered shape. A tip surface 940 of the tip portion 94 of the second rib 93 is an inclined surface that extends in an inclined manner so that the radially outer side is positioned closer to the tip. The tip surface 940 also faces the base end surface 855 of the pushing portion 85 in the axial direction. In this embodiment, the tip surface 940 extends parallel to the base end surface 855 of the pushing portion 85.

[0283] 30 , second rib 93 passes between circumferentially adjacent other-side protrusions 74 in other-side slit 701, i.e., between circumferentially adjacent push-in guide portions 6. Furthermore, second rib 93 prevents wobbling of second shaft portion 8 relative to first shaft portion 7 by passing between circumferentially adjacent other-side protrusions 74 in other-side slit 701 from the initial state through the first liquid medicine ejection, the second liquid medicine ejection, and until the liquid medicine ejection is completed.

[0284] The first rib 92 and the second rib 93 are provided at positions facing each other across the central axis of the second main shaft portion 80. Specifically, the first rib 92 and the second rib 93 face each other at positions spaced 180° apart in the circumferential direction of the second main shaft portion 80.

[0285] It should be noted that each functional part of the syringe 1 may have a different shape that has a similar function.

[0286] According to the present invention, it is possible to provide a syringe that can reliably perform multiple ejections.

[0287] The syringe of the present invention is a syringe for administering contents in portions, and comprises: a barrel having a tip end for discharging the contents and a base end located on the opposite side of the tip end in the axial direction; a plunger that can be pushed into the barrel from the base end toward the tip end, the plunger comprising a first shank and a second shank that is inserted into the first shank and is movable in the axial direction relative to the first shank; and a biasing member that biases the second shank toward the base end side relative to the first shank, the first shank being a restricting locking portion that restricts movement of the second shank relative to the first shank by the biasing force of the biasing member, the restricting locking portion being a plurality of restricting locking portions provided at intervals in the axial direction; and a push-in locking portion with which the second shaft locks when the second shaft is pushed into the opening, the second shaft comprising a push-in locked portion that locks with the push-in locking portion when the second shaft is pushed in, and a restricting portion, the restricting portion being configured to be rotatable around the starting end between a restricted retracted position where a free end on the base end side of the restricting portion is positioned radially inward, and a restricted expanded position where the free end is positioned radially outward, the free end comprising a restricted locked portion that locks with the restricted locking portion by the biasing force of the biasing member at the restricted expanded position, and a restricting release portion that moves the restricting portion from the restricted expanded position to the restricted retracted position at a position where the pushing for administering the one dose of content is completed, thereby releasing the lock of the restricted locked portion with the restricted locking portion.

[0288] According to this configuration, the engagement between the restricting locking portion and the restricting locked portion restricts the movement of the second shank toward the base end relative to the first shank due to the biasing force of the biasing member. When the plunger is pushed in, the engagement between the pushing locking portion and the pushing locked portion ensures that the entire plunger is pushed in and dispensed. Furthermore, when one push (dispensing) is completed, the restriction release portion disengages the restricting locking portion from the restricting locked portion, causing the second shank to move toward the base end relative to the first shank due to the biasing force of the biasing member. The restricting locked portion then forms a next lock (restriction) with the next restricting locking portion located axially proximal to the previously engaged restricting locking portion, and the pushing locking portion and the pushing locked portion form a next lock (pushing). In this way, the syringe is reliably switched to prepare for the next dispense, ensuring multiple dispenses.

[0289] In addition, in the syringe, the regulating portion may be moved to the regulating retracted position by the regulating release portion, and then moved to the regulating deployed position between one of the plurality of regulating engagement portions that has been engaged for administering the one dose of contents and a regulating engagement portion adjacent to the regulating engagement portion that has been engaged for administering the one dose of contents on the base end side in the axial direction.

[0290] According to this configuration, the restricting portion switches to the restrictive deployment position on the tip side of the next restrictive locking portion, so that the restricted locked portion is reliably locked to the next restrictive locking portion.

[0291] Moreover, in the syringe, the first shank includes a first main shank extending along the axial direction, the push-in locking portion includes a plurality of main shaft push-in locking portions provided on the first main shaft with axial spacing, the second shank includes a second main shaft extending along the axial direction and a push-in portion provided on the second main shaft, the push-in portion including a push-in portion configured to be rotatable around a starting end on the base end side of the push-in portion between a push-in retracted position where a free end on the tip side of the push-in portion is located radially inward and a push-in deployed position where the free end is located radially outward, and the push-in locked portion may include a main shaft push-in locked portion provided at the free end of the push-in portion, which locks with the main shaft push-in locked portion at the push-in deployed position during the pushing operation.

[0292] According to this configuration, the pushing portion rotates between the pushing-in deployed position and the pushing-in retracted position, thereby switching between engagement and disengagement between the spindle pushing-in locking portion and the spindle pushing-in locked portion, so that the spindle pushing-in locked portion is securely engaged with the next spindle pushing-in locking portion located axially toward the base end side of the spindle pushing-in locking portion to which it was previously engaged.

[0293] The syringe may also include a push-in guide portion between two axially adjacent spindle push-in locking portions that guides the push-in portion from the push-in deployment position to the push-in retract position, and the push-in guide portion may hold the push-in portion in the push-in retract position when the push-in portion moves axially from the spindle push-in locking portion on the tip side to the spindle push-in locking portion on the base side, and may release the hold of the push-in portion when the push-in portion is positioned on the base side relative to the base side spindle push-in locking portion.

[0294] According to this configuration, the pushing portion switches to the pushing and expanding position at a position on the axial base end side of the next spindle pushing and locking portion, so that the spindle pushing and locked portion is securely locked to the next spindle pushing and locking portion.

[0295] DESCRIPTION OF SYMBOLS 1...syringe, 2...barrel, 3...plunger, 4...biasing member, 5...restriction release portion, 6...push-in guide portion (main shaft push-in guide portion), 7...first shaft portion, 8...second shaft portion, 9...discharge nozzle, 20...tip portion, 21...base end portion, 22...barrel body, 23...finger grip, 24...discharge completion locking portion, 30...piston, 70...first main shaft portion, 71...first base end portion, 72...first tip portion, 73...one side convex portion, 74...other side convex portion, 75...convex portion, 76...regulation locking portion (main shaft regulation locking portion), 77...push-in locking portion (main shaft push-in locking portion), 80...second main shaft portion, 81...second base end portion, 82...regulation locked portion, 83 ...Regulating portion, 84...Push-in locked portion (main shaft push-in locked portion), 85...Push-in portion, 86...Discharge completion locked portion, 87...Discharge completion portion, 88, 89...Protruding portion, 90, 91...Recessed portion, 92...First rib, 93...Second rib, 94...Tip portion, 220...Main body tip portion, 221...Main body base end portion, 222...Main body connection portion, 223...Flange portion, 230...Grip main body portion, 231...Grip extension portion, 232...Main body base end portion, 233...Main body tip portion, 234...Grip base end side extension portion, 240...Base end surface, 600...Tip surface, 700...One side slit, 701...Other side slit, 702...Guide surface, 710...Base end Surface, 731, 732, 733, 734, 735... One side convex part, 741, 742, 743, 744... Other side convex part, 751, 752, 753, 754, 755...Convex portion, 760...Distal end surface, 770...Proximal end surface, 800...Second main wall portion, 801...Second sub-wall portion, 810...Distal end surface, 820...Proximal end surface , 830... Starting point end, 831... Free end, 832... Regulation guided part, 833... Regulation extension part, 840... Distal end surface, 841... Proximal end surface, 850... Originating end, 851... Free end, 852... Pushed guided part, 853... Pushed extension part, 854... Outer surface, 855... Proximal end surface, 860... Distal end surface, 870... Discharged guide 871, 872...Discharge extension part, 873...Outer surface, 880...Protrusion guided part, 881...Protrusion extension part, 890...Protrusion guided part, 891, 892, 893...Protrusion, 930...Outer surface, 940...Distal surface, 2320...Proximal end surface, 2321...End portion, 2340...Proximal end surface, 7311...Distal surface, 7 321... Tip surface, 7310, 7320, 7330, 7340, 7350... Guide surface, 7331, 7341, 7351... Tip surface, 7410, 7420, 7430, 7440...Guide surface, 7411, 7421, 7431...Proximal end surface, 7412, 7422, 7432...Distal end surface, 7510,7520, 7530, 7540, 7550... Guide surface, 7511, 7521, 7531, 7541, 7551... Tip surface, 7512, 7522 ...Proximal surface, 8320...Outer surface, 8321...End surface, 8330, 8520, 8530, 8700...Outer surface, 8710, 8720...Inner surface, 8800...Outer surface , 8810...Inner surface, 8900...Outer surface, 8910...Protruding guided portion, 8911...Outer surface, 8920...Protruding guided portion, 8921...Protruding extension portion, 8 922...Outer surface, 8923...Inner surface, 8930...Protruding guided portion, 8931...Proximal side protruding extension part, 8932...Distal side protruding extension part, 8933...Outer surface, 8934, 8935...inner surface, 901...syringe-type sprayer, 902...syringe, 903...plunger, 903a...first shaft member, 903b...second shaft member, 931...first elastic piece, 931a, 932a, 933a...base end portion, 931b, 932b, 933b...free end portion, 931d, 932d, 933d...locking protrusion, 932...second elastic piece, 933...third elastic piece, 936...tubular portion, 941...pressing shaft, 942...pressing flange, 945a...first support portion, 945b...second support portion, 945c...third support portion, 946a...first pressing portion, 946b...second pressing portion, 946c...third pressing portion,

Claims

1. A syringe for dividing and administering contents, comprising: a barrel having a tip end for discharging the contents and a base end located on the opposite side of the tip end in the axial direction; a plunger capable of being pushed into the barrel from the base end towards the tip end, the plunger comprising a first shaft portion and a second shaft portion inserted into the first shaft portion and movable in the axial direction relative to the first shaft portion; and a biasing member for biasing the second shaft portion towards the base end side relative to the first shaft portion, the first shaft portion comprising: a restricting locking portion for restricting movement of the second shaft portion relative to the first shaft portion due to the biasing force of the biasing member, the restricting locking portion being provided at intervals in the axial direction; a push-in locking portion with which the second shaft portion locks when the plunger for administering one dose of contents is pushed into the barrel, the second shaft portion comprising: a push-in locked portion that locks with the push-in locking portion when the plunger is pushed into the barrel; and a restricting portion, the regulating portion is configured to be rotatable about the starting end between a regulating retracted position where a free end on the base end side of the regulating portion is located radially inward and a regulating deployed position where the free end is located radially outward, and the free end is provided with a regulating engaged portion that engages with the regulating engaging portion by the biasing force of the biasing member at the regulating deployed position; and a regulating release portion that moves the regulating portion from the regulating deployed position to the regulating retracted position at a position where the pushing for administering one dose of content is completed, thereby releasing the engagement of the regulating engaged portion with the regulating engaging portion.

2. A syringe as described in claim 1, wherein after the regulating portion is moved to the regulating retracted position by the regulating release portion, the regulating portion moves to the regulating deployed position between a regulating engagement portion among the plurality of regulating engagement portions that has been engaged for administering the one dose of contents and a regulating engagement portion adjacent to the regulating engagement portion that has been engaged for administering the one dose of contents on the base end side in the axial direction.

3. The syringe according to claim 1 or claim 2, wherein the first shaft portion comprises a first main shaft portion extending in the axial direction, the push-in locking portion comprises a plurality of main shaft push-in locking portions provided on the first main shaft portion so as to be spaced apart in the axial direction, the second shaft portion comprises a second main shaft portion extending in the axial direction and a push-in portion provided on the second main shaft portion, the push-in portion comprises a push-in portion configured to be rotatable about a starting end on the base end side of the push-in portion between a push-in retract position in which a free end on the tip side of the push-in portion is located radially inward and a push-in deployed position in which the free end is located radially outward, and the push-in locked portion is a main shaft push-in locked portion provided at the free end of the push-in portion and includes a main shaft push-in locked portion that locks with the main shaft push-in locking portion at the push-in deployed position during the pushing.

4. A syringe as described in claim 3, further comprising a push-in guide portion between two axially adjacent spindle push-in locking portions which guides the push-in portion from the push-in deployed position to the push-in retracted position, wherein the push-in guide portion holds the push-in portion in the push-in retracted position when the push-in portion moves axially from the spindle push-in locking portion on the tip side to the spindle push-in locking portion on the base side of the two spindle push-in locking portions, and releases the hold of the push-in portion when the push-in portion is positioned on the base side relative to the spindle push-in locking portion on the base side.

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