3D needle assembly

Abstract

To provide a novel needle assembly which can selectively achieve easy assembly to a needle hub and stable maintenance of an assembled state or both.SOLUTION: A needle assembly 12 includes a puncture needle 16 where a needle hub 18 is provided on a proximal end side and a needle tip protector 10 which is externally inserted in the needle hub 18 and is movable in a needle axis direction from a puncture position where the puncture needle 16 is exposed to a protection position where a needle tip 20 of the puncture needle 16 is covered. On the needle tip protector 10, at least one flexible piece 68 which allows bending and deformation in an intersecting direction with a needle axis is provided. The flexible piece 68 includes a slit as a fitting part which is mutually fit to a part of the needle hub 18 and is positioned in a circumferential direction and an inner inclination part 76 which is inclined in at least one of the needle axis direction and the intersecting direction with the needle axis on an inner surface.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a needle assembly provided with a tip protector that covers the tip of a puncture needle by moving in the axial direction of the puncture needle.

Background Art

[0002] Conventionally, puncture needles such as indwelling needles used for infusion, blood collection, hemodialysis, etc. are known. The puncture needle body has a structure in which a needle hub is fixed to the proximal end side of a puncture needle having a sharp tip, for example. Then, the puncture needle body is punctured and indwelling in a body lumen such as a patient's blood vessel, and an external conduit is connected to the needle hub, whereby infusion, blood collection, hemodialysis, etc. are performed through the lumen of the puncture needle body and the external conduit.

[0003] In addition, the puncture needle body is combined with a tip protector that protects the tip of the puncture needle removed from the body lumen for the purpose of preventing accidental puncture after use, preventing frequent use, or facilitating disposal, etc., to constitute a needle assembly. As the tip protector and the needle assembly including the same, for example, it is disclosed in Japanese Patent Application Laid-Open No. 2017-196060 (Patent Document 1). That is, according to the medical needle with a protector of Patent Document 1, when the needle tube is pulled out from a blood vessel or the like, the needle tube moves toward the proximal end side with respect to the protector, and the needle tube removed from the patient is accommodated in the inner circumference of the protector so that the tip of the needle tube is not exposed to the outside.

[0004] By the way, the medical needle with a protector of Patent Document 1 includes a slide mechanism that allows the needle hub to move in the axial direction with respect to the protector. The slide mechanism of Patent Document 1 is configured by a slit provided in a side wall portion of the protector being slidably fitted in the axial direction with respect to a protrusion provided on the hub.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] In the structure of Patent Document 1, the hub and protector are assembled by rotating the protector relative to the hub. At this time, because the side wall is flexible, the side wall bends in the direction intersecting the needle axis as the ridge comes into contact with the side wall due to the rotation of the hub. Subsequently, the assembly of the hub and protector is completed when the ridge is inserted into a slit provided in the side wall.

[0007] However, upon further detailed examination by the inventors, it was found that in Patent Document 1, when the protector is assembled to the hub by rotating it relative to the hub, the side wall portion bends while making overall contact with the protrusion, which could damage the side wall portion. Furthermore, the assembly of the hub and protector required considerable force, indicating that ease of assembly was not considered. On the other hand, since the assembled state of the hub and protector can be released by the relative rotation of the hub and protector, there was a need to make it more difficult for the hub and protector to rotate relative to each other, thereby making it more difficult for the assembled hub and protector to be released.

[0008] The problem to be solved by the present invention is to provide a novel needle assembly that can selectively or simultaneously achieve ease of assembly to the needle hub and stable maintenance of the assembled state to the needle hub. [Means for solving the problem]

[0009] The following describes preferred embodiments for understanding the present invention. However, each embodiment described below is illustrative and can be combined with others as appropriate. Furthermore, the multiple components described in each embodiment can be recognized and adopted as independently as possible, and can be combined with any component described in another embodiment as appropriate. Thus, the present invention is not limited to the embodiments described below, and various other embodiments can be realized.

[0010] The first embodiment is a needle assembly comprising a puncture needle having a needle hub on its base end, and a needle tip protector externally mounted on the needle hub and movable in the needle axis direction from a puncture position where the puncture needle is exposed to a protective position covering the needle tip of the puncture needle, wherein the needle tip protector is provided with at least one flexible piece that allows bending deformation in the direction intersecting the needle axis, the flexible piece having a fitting portion that fits together with a part of the needle hub and is positioned in the circumferential direction, and the flexible piece on both sides in the circumferential direction constituting the fitting portion has an inner surface that is oriented in the direction intersecting the needle axis Towards An inclined inner section is provided. Alternatively, one of the flexible pieces on both sides in the circumferential direction that constitute the fitting portion is provided with an inclined portion on its inner surface that slopes in the direction intersecting the needle axis. It is.

[0011] According to the needle assembly structure in accordance with this embodiment, for example, by providing an inclined portion on the flexible piece that is inclined in the direction of the needle axis, when the needle hub rotates relative to the needle tip protector while pushing the flexible piece outward during assembly of the needle tip protector and the needle hub, the contact area between the needle hub and the flexible piece and the cross-sectional area of ​​the flexible piece can be reduced. As a result, the force required to rotate the needle tip protector and the needle hub relative to each other during assembly of the needle tip protector and the needle hub is reduced, improving ease of assembly.

[0012] Furthermore, for example, if the flexible piece is provided with an inner inclined portion that slopes in the circumferential direction, which is the direction intersecting the needle axis, and the flexible piece is made thinner toward the fitting portion, the contact pressure between the needle hub and the flexible piece when the needle tip protector is rotated relative to the needle hub is reduced, and the force required to rotate the needle tip protector and the needle hub relative to each other is reduced.

[0013] Furthermore, for example, if the flexible piece is provided with an inclined portion that slopes in the circumferential direction, which is the direction intersecting the needle axis, and the flexible piece is made thicker toward the fitting portion, the fitting between the needle hub and the flexible piece at the fitting portion becomes less likely to come undone. As a result, relative rotation of the assembled state of the needle hub and the needle tip protector is prevented, which prevents the needle hub from coming loose from the needle tip protector, and the assembled state of the needle tip protector and the needle hub is maintained stably.

[0014] As described above, the structure according to the first embodiment makes it possible to selectively or simultaneously achieve ease of assembly to the needle hub and maintenance of the assembled state of the needle tip protector and the needle hub.

[0015] A second embodiment is a needle assembly described in the first embodiment, wherein the flexible piece has a contact portion that contacts the needle hub in the needle axis direction at the protective position of the needle tip protector to prevent the needle hub from coming off the needle tip protector toward the base end.

[0016] According to the needle assembly structured in this embodiment, the contact portion provided on the flexible piece contacts the needle hub, thereby preventing the needle hub from coming off the needle tip protector towards the base end.

[0017] A third embodiment is a needle assembly according to the first or second embodiment, wherein at least one flexible piece has a projection that protrudes from the inner surface, and the inclined portion is configured to include the projection.

[0018] According to the needle assembly structured in this embodiment, the strength of the flexible piece can be increased in the portion where the protrusion is provided. Therefore, the strength of the flexible piece and the manner in which the needle hub and the flexible piece come into contact during relative rotation of the needle hub and the needle tip protector can be adjusted with a large degree of freedom by changing the shape, size, position, and number of protrusions.

[0019] The fourth aspect is a needle assembly described in any one of the first to third aspects, wherein at least one first flexible piece and at least one second flexible piece are formed as the flexible piece on the base end side of the needle tip protector, the first flexible piece protruding toward the base end in the direction of the needle axis, and the second flexible piece protruding toward the tip in the direction of the needle axis.

[0020] According to the needle assembly having a structure according to this aspect, in a state where the tip of the puncture needle is protected by the needle tip protector, for example, the first flexible piece prevents the tip of the needle from being re-exposed to the distal end side, and the second flexible piece prevents the needle tip from being re-exposed to the proximal end side, in other words, prevents the needle hub from coming off the needle tip protector to the proximal end side.

[0021] A fifth aspect is the needle assembly according to any one of the first to fourth aspects, wherein the needle tip protector includes a cylindrical peripheral wall, and an outer dimension of the peripheral wall in a direction perpendicular to the axis is different in the circumferential direction, and a pair of the flexible pieces are provided so as to face each other in a direction perpendicular to the axis of a wide portion with a large outer dimension and a narrow portion with a small outer dimension, and the pairs of flexible pieces have different shapes from each other.

[0022] According to the needle tip protector having a structure according to this aspect, since a pair of flexible pieces are provided so as to face each other in a direction perpendicular to the axis of the wide portion and the narrow portion, for example, when the flexible piece abuts on the needle hub side to prevent the needle hub from coming off the needle tip protector or the needle tip from being re-exposed, the force acting between the needle hub and the needle tip protector due to the locking between the flexible piece and the needle hub side acts in a well-balanced manner in the circumferential direction, and it is difficult for relative tilting between the needle hub and the needle tip protector to occur.

[0023] Further, a pair of flexible pieces facing each other in the direction perpendicular to the axis where the wide portion is provided are easy to provide a space on the outer peripheral side and are easy to allow deformation to the outer peripheral side. On the other hand, a pair of flexible pieces facing each other in the direction perpendicular to the axis where the narrow portion is provided are restricted in the space on the outer peripheral side, so that deformation to the outer peripheral side is likely to be restricted. Therefore, by making the pairs of flexible pieces have different shapes from each other, the action of preventing the needle hub from coming off by each flexible piece can be effectively obtained.

[0024] By the way, in the structure of Patent Document 1, the contact area between a part of the hub inserted into the slit and the slit is not sufficient, and although there is a possibility that the hub and the protector may come off when they are relatively rotated after the hub and the protector are assembled, it has also become clear that sufficient consideration has not been made.

[0025] One aspect of an invention different from the present invention made to solve such problems is a needle assembly having a puncture needle provided with a needle hub on the proximal end side, and a needle tip protector that is externally inserted and attached to the needle hub and is movable in the needle axis direction from a puncture position where the puncture needle is exposed to a protection position covering the needle tip of the puncture needle. The needle tip protector is provided with at least one flexible piece that allows bending deformation in a direction intersecting the needle axis. The flexible piece includes a fitting portion that is fitted to a part of the needle hub and positioned in the circumferential direction, and an outer inclined portion that inclines at least in one of the needle axis direction and the direction intersecting the needle axis on the outer surface.

[0026] According to the needle assembly having the structure according to this aspect, when the needle hub and the needle tip protector are assembled and the flexible piece is fitted to the needle hub at the fitting portion, the contact area between the needle hub and the fitting portion of the flexible piece becomes large. As a result, in the assembled state of the needle hub and the needle tip protector, relative rotation between the needle hub and the needle tip protector is likely to be prevented, and the needle hub is prevented from coming off the needle tip protector.

Advantages of the Invention

[0027] According to the present invention, in the needle assembly, it is possible to selectively or concurrently achieve ease of assembly to the needle hub and stable maintenance of the assembled state with respect to the needle hub.

Brief Description of the Drawings

[0028] [Figure 1] Perspective view showing the needle assembly as the first embodiment of the present invention [Figure 2] Longitudinal sectional view of the needle assembly shown in FIG. 1, corresponding to the II-II section of FIG. 3 [Figure 3] III-III sectional view of FIG. 2 [Figure 4] IV-IV sectional view of FIG. 3 [Figure 5] Perspective sectional view of the needle tip protector constituting the needle assembly shown in FIG. 1 [Figure 6]A cross-sectional view showing the protection of the needle tip by the needle tip protector in the needle assembly shown in Figure 1. [Figure 7] Perspective cross-sectional view of a needle tip protector as a reference embodiment. [Figure 8] Perspective cross-sectional view of a needle tip protector as a second embodiment of the present invention [Figure 9] Cross-sectional view of a needle tip protector as a reference embodiment. [Figure 10] Cross-sectional view of a needle tip protector as a third embodiment of the present invention [Figure 11] Cross-sectional view of a needle tip protector as a reference embodiment. [Figure 12] Cross-sectional view of a needle tip protector as a fourth embodiment of the present invention [Modes for carrying out the invention]

[0029] Embodiments of the present invention will be described below with reference to the drawings.

[0030] Figures 1-4 show a needle assembly 12 equipped with a needle tip protector 10 as a first embodiment of the present invention. As shown in Figures 2 and 3, the needle assembly 12 has a structure in which a puncture needle body 14, such as an indwelling needle, is inserted into the needle tip protector 10 so as to be movable in the direction of the needle axis of the puncture needle 16, which will be described later. The needle tip protector 10 can cover at least the needle tip 20 (described later) of the puncture needle body 14. In the following description, as a general rule, the tip side refers to the left side in Figure 2, which is the side of the needle tip 20 of the puncture needle body 14, and the proximal end side refers to the right side in Figure 2, which is the rear in the direction of puncture of the puncture needle body 14. Also, as a general rule, the up and down direction refers to the up and down direction in Figure 3, which is the vertical direction, and the left and right direction refers to the up and down direction in Figure 2, which is the horizontal direction.

[0031] More specifically, the puncture needle body 14 has a structure in which a needle hub 18 is fixed to the proximal end of the puncture needle 16. The puncture needle 16 is made of a metal such as stainless steel, and has a needle tip 20 at one end that has a sharp, tapered shape.

[0032] The needle hub 18 is generally cylindrical in shape, and the proximal end of the puncture needle 16 is fixed to its tip in an inserted state. This connects the lumen of the needle hub 18 and the lumen of the puncture needle 16 in the direction of the needle axis.

[0033] The needle hub 18 is equipped with a tip portion 22. The tip portion 22 is substantially cylindrical in shape and has a needle fixing portion 24 into which the proximal end of the puncture needle 16 is inserted from the tip side and fixed. The tip side of the needle fixing portion 24 is provided with tip locking portions 26, 26 that protrude to both sides in the vertical direction. Furthermore, on the proximal end side of the needle fixing portion 24 beyond the tip locking portions 26, 26, there is provided with a pair of locking protrusions 28, 28 that protrude to both sides in the horizontal direction. The surface of the locking protrusions 28 on the tip side is wide in the direction perpendicular to the axis, and the surface on the proximal end side is inclined, so that the protruding height decreases toward the proximal end.

[0034] The tip portion 22 is provided with a pair of guide ridges 30, 30 that protrude in both directions in the vertical direction. The guide ridges 30 are roughly rectangular in shape and extend linearly from the base end side of the tip locking portion 26 to the base end of the tip portion 22. The tip of the guide ridge 30 is connected to the tip locking portion 26, and the base end is connected to the base end portion 32, which will be described later.

[0035] A base end portion 32 is provided on the base end side of the needle hub 18, beyond the tip portion 22. In this embodiment, the base end portion 32 is integrally formed with the tip portion 22. However, the base end portion 32 may be formed separately from the tip portion 22 and fixed to the tip portion 22 by means of adhesive or other means. The outer dimensions of the base end portion 32 in the direction perpendicular to the axis are larger than those of the tip portion 22, and as a result, the outer dimensions of the needle hub 18 in the direction perpendicular to the axis are larger on the base end side than on the tip side.

[0036] The base end portion 32 of the needle hub 18 has a conduit connection portion 34 which is substantially cylindrical in shape. The conduit connection portion 34 constitutes the base end side of the base end portion 32. The outer dimensions of the conduit connection portion 34 in the direction perpendicular to the axis are larger than those of the tip portion 22 of the needle hub 18. A connection hole 36 is formed in the conduit connection portion 34, which opens to the base end face. The connection hole 36 has a substantially circular cross-section. The connection hole 36 has a bottom portion 38 on the tip side, which is opposite the opening. The inner hole of the conduit connection portion 34 penetrates the bottom portion 38 in the axial direction and communicates with the inner hole of the connection port 40, which will be described later. The diameter of the connection hole 36 is larger on the base end side, which is the opening side, than on the tip end side, which is the bottom portion 38 side. The diameter of the connection hole 36 gradually increases from the bottom portion 38 side toward the opening end, which is the base end side, and the inner surface of the peripheral wall of the connection hole 36 is tapered on the bottom portion 38 side.

[0037] A connection port 40 is provided at the bottom 38 of the connection hole 36. The connection port 40 is cylindrical and protrudes from the bottom 38 toward the base end toward the opening of the connection hole 36. The inner circumferential surface of the connection port 40 is a cylindrical surface with a substantially constant diameter in the axial direction. The outer circumferential surface of the connection port 40 has a tapered outer circumferential surface, with the diameter gradually decreasing toward the base end in the axial direction. The connection port 40 may be a separate component from the pipe connection part 34, but in this embodiment it is integrally formed with the pipe connection part 34.

[0038] A pair of arms 42, 42 are provided at the base end portion 32 of the needle hub 18. The arms 42 extend laterally (up and down in Figure 2) from the base end of the conduit connection portion 34 on both sides, and are curved and extend toward the tip, and are provided on both sides laterally with a predetermined gap between them and the base end portion 32. The connection portion of the arms 42, 42 to the conduit connection portion 34 is curved and narrow, allowing for elastic deformation in a direction that brings them closer together when external forces are applied. In addition, hooks 44 are formed at the tips of each of the arms 42, 42.

[0039] The base portion 32 is attached to the connection port 40 in an external state by inserting the tip of the external conduit 46 into the connection hole 36 of the conduit connection portion 34. The external conduit 46 is, for example, a tube made of synthetic resin. The external conduit 46 is bonded or welded to the inner circumferential surface of the connection hole 36 and the connection port 40 as needed.

[0040] The external conduit 46 is connected to the conduit connection part 34, so that the tip portion 22 and the external conduit 46 are connected on both sides of the base portion 32, and the lumen of the puncture needle 16 and the lumen of the needle hub 18 are in communication with the external conduit 46. As a result, a fluid passage 48 is provided in the puncture needle body 14, extending from the tip opening of the puncture needle 16 to the external conduit 46.

[0041] As shown in Figures 1-5, the needle tip protector 10 has a roughly cylindrical shape that extends in the direction of the needle axis. The needle tip protector 10 is integrally molded from a hard synthetic resin such as polypropylene, polycarbonate, glycol-modified polyethylene terephthalate, ABS resin, or MBS resin. Preferably, the needle tip protector 10 is transparent or semi-transparent, allowing the transmission of visible light. The needle tip protector 10 has a cylindrical peripheral wall 50, and an inner hole 52 is formed in the inner circumference of the peripheral wall 50 that penetrates in the direction of the needle axis.

[0042] The peripheral wall 50 has a cylindrical portion 54 at the tip end that has a roughly circular cross-section, and an enlarged portion 56 at the base end that is larger in diameter than the cylindrical portion 54 and widens outwards, so that the shape differs in the direction of the needle axis.

[0043] The enlarged portion 56 has a roughly elliptical cylindrical shape, and the width of the outer surface in the left-right direction (lateral direction) in Figure 4, which is the larger diameter direction, is larger than the width of the outer surface in the up-down direction (vertical direction) in Figure 4, which is the smaller diameter direction. Of the wall portions constituting the enlarged portion 56, the parts constituting the vertical wall portions are narrow portions 58, 58, while the parts constituting the horizontal wall portions are wide portions 60, 60. The opposing directions of the narrow portions 58, 58 and the opposing directions of the wide portions 60, 60 are roughly perpendicular to each other. On the inner circumference of the enlarged portion 56, an internal space 62 having a flattened cross-section where the horizontal dimension is larger than the vertical dimension is formed at the base end portion of the inner hole 52 that penetrates the needle tip protector 10. The internal space 62's horizontal inner dimension gradually increases towards the base end. In this embodiment, the enlarged portion 56 has narrow portions 58, 58 and wide portions 60, 60, but for example, it may have a substantially constant width dimension around its entire circumference.

[0044] The wide sections 60,60 have through-windows 64,64 formed therein, which serve as engaging parts that penetrate in the thickness direction of the plate. The circumferential dimensions of the through-windows 64,64 are larger than the circumferential dimensions of the hooks 44,44.

[0045] The peripheral wall 50 of the needle tip protector 10 is provided with a pair of projections 66, 66 that protrude from the cylindrical portion 54 toward the base end. The projections 66, 66 are positioned corresponding to the wide portions 60, 60, are positioned opposite each other in the lateral direction, and are spaced apart from each other in the circumferential direction. The tip portions of the projections 66, 66 that connect to the cylindrical portion 54 extend approximately parallel to the needle axis direction. The projections 66, 66 have a tapered shape in which both the inner and outer surfaces in the lateral direction incline toward the base end. The projections 66, 66 are each curved in the circumferential direction. The radial distance between opposing surfaces at the protruding tips of the projections 66, 66 is slightly larger than the outer diameter dimension of the tip portion 22.

[0046] Furthermore, the protruding tips (base ends in the direction of the needle axis) of the projections 66, 66 are located closer to the tip in the direction of the needle axis than the base end of the enlarged portion 56. Therefore, the entire projections 66, 66 are housed within the internal space 62 of the enlarged portion 56; in other words, the enlarged portion 56 is located outside the projections 66, 66.

[0047] The enlarged portion 56 is composed of flexible side wall portions 68, 68, and the side wall portions 68, 68 are provided on the inner circumference of the enlarged portion 56. As shown in Figures 3 and 4, the side wall portions 68 are plate-shaped and extend in directions intersecting the longitudinal direction. The side wall portions 68 are provided on the inner circumference side of the narrow portions 58, 58, and are arranged opposite each other at a predetermined distance in the longitudinal direction in which the narrow portions 58, 58 are provided. Therefore, the opposing directions of the side wall portions 68, 68 are approximately perpendicular to the opposing directions of the projections 66, 66.

[0048] The side wall portions 68, 68 are provided at a distance on the inner circumference side from the narrow portions 58, 58 of the enlarged portion 56. As a result, a gap 70, 70 is formed between the side wall portions 68, 68 and the narrow portions 58, 58, at least in the central circumferential portion of the narrow portions 58, 58. The side wall portions 68, 68 are provided on the tip side of the base end (protruding tip) of the projection 66, 66. The distance between the side wall portions 68, 68 in this embodiment is approximately equal to the outer diameter dimension of the tip portion 22 of the needle hub 18. Furthermore, the tip end of the side wall portion 68 is a contact portion 71 that abuts the tip locking portion 26 in the needle axis direction when the needle tip protector 10 is in the protective position described later.

[0049] Each side wall portion 68 is composed of a pair of leaf springs 72, 72 and is elastically deformable in the thickness direction. The leaf springs 72, 72 are integrally formed with the wide portions 60, 60 of the enlarged portion 56 and protrude laterally inward from the wide portions 60, 60. The protruding tips of the leaf springs 72, 72 are separated from each other in the lateral direction. A slit 74 is formed between the protruding tips of the leaf springs 72, 72 in the side wall portion 68, serving as a fitting portion that extends in the axial direction. When the puncture needle body 14, which will be described later, is inserted into the needle tip protector 10, a guide projection 30, which is part of the needle hub 18, is inserted into the slit 74. The guide projection 30 is movable within the slit 74 while being guided in the axial direction, thereby allowing axial movement of the needle hub 18 relative to the needle tip protector 10. Furthermore, the guide ridge 30 is inserted into the slit 74 in a fitted state with circumferential displacement relative to the slit 74.

[0050] Each leaf spring 72 constituting the side wall portion 68 is provided with an inner inclined portion 76. That is, as shown in Figures 3 and 5, the outer surface in the vertical direction, which is the outer surface of the leaf spring 72, extends approximately perpendicular to the vertical direction, and the inner surface in the vertical direction, which is the inner surface of the leaf spring 72, is an inner inclined portion 76 that is inclined with respect to the outer surface in the vertical direction. The inner inclined portion 76 is inclined inward in the vertical direction toward the tip side in the axial direction, and the leaf spring 72 gradually becomes thicker at approximately a constant rate toward the tip side. In other words, a projection is provided on the inner surface of the leaf spring 72 that protrudes inward in the vertical direction, and the inner inclined portion 76 is formed by the surface of the inclined projection. Due to the provision of the inner inclined portion 76, the distance between the opposing side walls 68, 68 gradually increases toward the base end side.

[0051] As shown in Figure 1, a wing-shaped portion 78 is provided at the tip of the needle tip protector 10. The wing-shaped portion 78 is made of, for example, a soft synthetic resin. The wing-shaped portion 78 is integrally formed with a cylindrical fitting cylinder portion 80, with plate-shaped connecting portions 82, 82 protruding tangentially from the fitting cylinder portion 80, and wing bodies 84 are integrally formed on the protruding tip sides of the connecting portions 82, 82 from the fitting cylinder portion 80. The wing-shaped portion 78 is attached to the peripheral wall 50 of the needle tip protector 10 by fitting the cylinder portion 80 onto the tip of the cylindrical portion 54.

[0052] The needle body 14 is inserted into the inner hole 52 of the needle tip protector 10 from the proximal end opening, thereby externally attaching the needle tip protector 10 to the needle body 14 and forming the needle assembly 12. Specifically, the needle body 14 is inserted until it is rotated 90° circumferentially with respect to the needle tip protector 10, with the tip locking portion 26 positioned towards the tip of the pair of side wall portions 68, 68, and the locking projection 28 positioned towards the tip of the protruding piece 66, 66. Then, the needle body 14 is rotated 90° circumferentially with respect to the needle tip protector 10, returning it to the orientation in which the previously rotated needle body 14 is assembled with respect to the needle tip protector 10. As a result, at the circumferential position where the tip locking portions 26,26 and the side wall portions 68,68 overlap in the axial direction, the base end faces of the tip locking portions 26,26 are positioned closer to the tip than the tip faces of the side wall portions 68,68. In addition, the locking projections 28,28 are inserted between the opposing projections 66,66, so that the tip faces of the locking projections 28,28 are positioned closer to the tip than the base end faces of the projections 66,66. Consequently, the puncture needle body 14 is inserted into the needle tip protector 10 toward the tip without locking between the tip locking portions 26,26 and the side wall portions 68,68, or locking between the locking projections 28,28 and the projections 66,66.

[0053] When the puncture needle body 14 is rotated while partially inserted into the needle tip protector 10, the guide protrusions 30, 30 provided on the tip portion 22 of the needle hub 18 elastically deform the leaf springs 72, 72 on each of the side wall portions 68, 68, and are inserted into the slits 74, 74. In this embodiment, the leaf springs 72 have a thin base, which reduces their deformation rigidity, allowing the rotation of the puncture needle body 14 relative to the needle tip protector 10 to be achieved with relatively little force.

[0054] In the initial state before use of the needle assembly 12, as shown in Figure 1, the needle tip protector 10 is positioned at a puncture location where the needle tip 20 of the puncture needle 16 is exposed further forward than the needle tip protector 10 relative to the puncture needle body 14. In this initial state, as shown in Figure 2, the hooks 44, 44 provided on the arms 42, 42 of the needle hub 18 are inserted into and engaged with the through windows 64, 64 provided on the enlarged portion 56 of the needle tip protector 10. This connects the needle tip protector 10 and the needle hub 18, maintaining the protruding state of the needle tip 20, and restricting the movement of the puncture needle 16 toward the base end in the needle axis direction due to resistance during puncture, for example, when puncturing by holding the wing-shaped portion 78.

[0055] In the initial state of the needle assembly 12, the protruding tips of the projections 66, 66 of the needle tip protector 10 are slightly separated from the outer circumferential surface of the tip portion 22. However, the projections 66, 66 may be in contact with the outer circumferential surface of the tip portion 22, and may be slightly pushed outward as a result.

[0056] The needle assembly 12 is used for infusion, blood sampling, and hemodialysis by inserting the puncture needle 16 into the patient's blood vessel and leaving the puncture needle body 14 in place, through the fluid channel 48. In this embodiment, the needle assembly 12 is provided with a wing-shaped portion 78, which allows the puncture needle 16 of the puncture needle body 14 to be inserted while, for example, pinching the wing-shaped portion 78. When leaving the puncture needle body 14 in the inserted state, it can be fixed with tape at the position of the wing-shaped portion 78, providing a large contact area with the skin.

[0057] When removing the puncture needle body 14, the arms 42, 42 of the needle hub 18 are pressed inward by the fingers while the needle tip protector 10 remains taped in place at the wing-shaped portion 78. This releases the engagement between the hooks 44, 44 and the through-windows 64, 64, allowing the puncture needle body 14 to be moved towards the proximal end relative to the needle tip protector 10. By moving the puncture needle body 14 towards the proximal end relative to the needle tip protector 10 and removing the puncture needle 16 from the skin, the needle tip protector 10 moves towards the needle tip 20 relative to the puncture needle body 14. In this way, the connection between the puncture needle body 14 and the needle tip protector 10 by the arms 42, 42 at the puncture position can be released by operating the arms 42, 42, and the release of the connection allows the puncture needle body 14 and the needle tip protector 10 to move relative to each other in the axial direction.

[0058] As shown in Figure 6, by moving the puncture needle body 14 backward to a predetermined protective position relative to the needle tip protector 10 (moving the needle tip protector 10 forward toward the needle tip 20 side of the puncture needle body 14), the needle tip 20 of the puncture needle 16 is housed within the inner circumference of the needle tip protector 10 and covered by the peripheral wall 50.

[0059] Guide ridges 30, 30, which are part of the needle hub 18, are inserted into slits 74, 74 provided in the side walls 68, 68 of the needle tip protector 10. The guide ridges 30, 30 are then guided by the side walls 68, 68 and can move axially within the slits 74, 74. As a result, when the puncture needle body 14 moves toward the proximal end relative to the needle tip protector 10, rattling of the puncture needle body 14 relative to the needle tip protector 10 is suppressed, and the puncture needle body 14 can move smoothly relative to the needle tip protector 10.

[0060] As the needle tip protector 10 moves to a protective position relative to the puncture needle body 14, the free ends of the projections 66, 66 move over the locking projections 28, 28 and toward the tip, causing the elastically restored projections 66, 66 to be positioned toward the tip relative to the locking projections 28, 28. Then, when the puncture needle body 14 attempts to move toward the tip relative to the needle tip protector 10, the base end faces of the projections 66, 66 abut against the tip faces of the locking projections 28, 28 and lock in place. As a result, the movement of the puncture needle body 14 toward the tip relative to the needle tip protector 10 is restricted by the locking of the projections 66, 66 and the locking projections 28, 28, preventing the re-exposure of the needle tip 20 of the puncture needle body 14.

[0061] If the puncture needle body 14 attempts to move further towards the proximal end relative to the needle tip protector 10, which is in a protected position, the tip locking portions 26, 26 provided on the needle hub 18 of the puncture needle body 14 abut against the contact portions 71 of the side walls 68, 68 of the needle tip protector 10 in the axial direction and lock into place. This restricts the movement of the puncture needle body 14 toward the proximal end and prevents the puncture needle body 14 from coming out toward the proximal end relative to the needle tip protector 10.

[0062] The side walls 68, 68 are provided with an inwardly inclined portion 76, which makes the thickness of the tip larger than the thickness of the base. Therefore, a larger contact area is secured between the base end surface of the tip locking portion 26, 26 and the tip end surface of the side walls 68, 68. As a result, the movement of the puncture needle body 14 toward the base end relative to the needle tip protector 10 is more reliably restricted by the locking of the tip locking portion 26, 26 and the side walls 68, 68.

[0063] In this way, with the needle tip 20 of the puncture needle 16 protected by the needle tip protector 10, the movement of the puncture needle body 14 relative to the needle tip protector 10 is restricted on both the tip and proximal ends, and the protective state of the needle tip 20 by the needle tip protector 10 is maintained.

[0064] In this embodiment, a pair of projections 66, 66 are provided, and coupled with the fact that the projections 66, 66 are integrally molded with the peripheral wall 50 of the needle tip protector 10, when the projections 66, 66 and the locking projections 28, 28 are locked together, rattling of the needle tip protector 10 relative to the puncture needle body 14 is prevented. By providing two or more projections 66 in this way, the retraction of the needle tip protector 10 toward the proximal end relative to the puncture needle body 14 is more reliably prevented, and the effect of preventing the re-exposure of the needle tip 20 can be exerted more stably. In this case, it is preferable that the multiple projections 66 are arranged substantially symmetrically with respect to the central axis of the needle tip protector 10.

[0065] With the needle tip 20 of the puncture needle body 14 protected by the needle tip protector 10, the tape fixing of the wing-shaped portion 78 is released and the needle assembly 12 is removed from the patient. However, the procedure for protecting the needle tip 20 is not limited to the procedure described above. Specifically, for example, the tape fixing of the wing-shaped portion 78 may be released, the entire needle assembly 12 may be moved backward to remove the puncture needle 16 from the blood vessel, and then the puncture needle body 14 may be moved backward relative to the needle tip protector 10 so that the needle tip 20 of the puncture needle 16 is protected.

[0066] Figure 7 shows a needle tip protector 90 that constitutes a needle assembly as a reference embodiment. The needle tip protector 90 has a pair of side wall portions 92, 92. In the following description, components and parts that are substantially the same as those in the first embodiment are denoted by the same reference numerals in the figures, and their descriptions are omitted.

[0067] The side wall portion 92 is composed of leaf springs 94. Although not explicitly shown in Figure 7, the side wall portion 92 has a structure in which a pair of leaf springs 94, 94 are provided flanking the slit 74, similar to the side wall portion 68 in the above embodiment. As shown in Figure 7, the outer surface of the leaf spring 94, which is the outer surface in the vertical direction (up and down direction in Figure 7), is an outer inclined portion 96 that slopes inward in the vertical direction toward the tip. Due to the provision of the outer inclined portion 96, the thickness dimension of the leaf spring 94 in the vertical direction decreases by approximately a constant rate toward the tip.

[0068] In this embodiment of the needle tip protector 90, when inserting and assembling a puncture needle (not shown), the leaf spring 94 pressed by the guide projection 30 can be easily deformed. Moreover, compared to the case where the entire leaf spring 94 is thin, the thickness of the leaf spring 94 is secured at the base end, so the deformation rigidity required for the leaf spring 94 is also secured, and the puncture needle can be effectively prevented from coming out of the needle tip protector 90 towards the base end.

[0069] Figure 8 shows a needle tip protector 100 that constitutes a needle assembly as a second embodiment of the present invention. The needle tip protector 100 comprises a pair of side wall portions 102, 102.

[0070] The side wall portion 102 is composed of leaf springs 104. Although not explicitly shown in Figure 8, the side wall portion 102 has a structure in which a pair of leaf springs 104, 104 are provided with a slit 74 in between, similar to the side wall portion 68 of the above embodiment. As shown in Figure 8, the leaf spring 104 has an inner inclined portion 76 on its inner surface in the vertical direction (up and down direction in Figure 8) that slopes inward in the vertical direction toward the tip, and an outer inclined portion 96 on its outer surface in the vertical direction that slopes inward in the vertical direction toward the tip. The inner inclined portion 76 on the inner surface and the outer inclined portion 96 on the outer surface are inclined at approximately the same angle. However, the inclination angles of the inner inclined portion 76 and the outer inclined portion 96 may be different, and as a result, the vertical thickness dimension of the leaf spring 104 may change in the axial direction.

[0071] In this embodiment of the needle tip protector 100, when the puncture needle body (not shown) inserted into the needle tip protector 100 is rotated to insert the guide projection (not shown) into the slit 74, the tip side of the leaf spring 104 partially contacts the guide projection and deforms. Therefore, compared to the case where the entire axial direction of the leaf spring 104 is deformed, the required force may be smaller, and it is expected that the assembly work of the puncture needle body and the needle tip protector 100 will be easier.

[0072] In this embodiment, the inner inclined portion 76 provided on the inner surface of the side wall portion 102 and the outer inclined portion 96 provided on the outer surface are inclined in the same direction. However, for example, the inner inclined portion and the outer inclined portion may be inclined in different directions.

[0073] Figure 9 shows a needle assembly 110 as a reference embodiment. The needle assembly 110 has a structure in which a needle tip protector 112 is attached to a puncture needle body 14 in an external state.

[0074] The needle tip protector 112 is provided with a pair of side wall portions 114, 114. The side wall portion 114 is composed of a pair of leaf springs 116, 116. In this embodiment, the leaf springs 116 gradually become thicker toward the inside in the lateral direction (left-right direction in Figure 9), which is the protruding tip side. That is, the lower surface of the leaf spring 116 is a non-inclined plane that extends substantially perpendicular to the vertical direction, and the outer surface in the vertical direction, which is the outer peripheral surface of the leaf spring 116, is an outward inclined portion 118 that inclins toward the outside in the vertical direction toward the inside in the lateral direction, which is the inside in the circumferential direction. As a result, the vertical thickness dimension of the inner lateral end of the leaf spring 116, which is on the slit 74 side, is greater than the vertical thickness dimension of the outer lateral end. In this embodiment, the protruding height dimension of the guide rib 30 of the needle hub 18 inserted into the slit 74 is substantially the same as the vertical thickness dimension of the inner lateral end of the leaf spring 116.

[0075] In this embodiment, the needle assembly 110, in its initial state before use when the puncture needle body 14 and needle tip protector 112 are combined, has guide protrusions 30, 30 of the needle hub 18 inserted into slits 74, 74 of the side wall portions 114, 114. Furthermore, the thickness of the leaf springs 116, 116 constituting the side wall portion 114 changes in the lateral direction, becoming thicker toward the inside in the lateral direction, and the protruding dimension of the guide protrusions 30 is approximately the same as the thickness of the inner end of the leaf springs 116, 116 in the lateral direction. Therefore, when a rotational force is applied to the needle hub 18 against the needle tip protector 112, the contact area between the guide protrusions 30, 30 and the inner end of the leaf springs 116, 116 in the lateral direction increases, making it difficult for the guide protrusions 30 to come out of the slits 74. Therefore, the needle hub 18 and the needle tip protector 112 are easily held in a orientation that allows the tip locking portion and side wall portions 114, 114 (not shown) and the locking projection and protrusions 66, 66 (not shown) to lock in the axial direction, and a stable protective state of the needle tip (not shown) by the needle tip protector 112 is achieved.

[0076] Figure 10 shows a needle assembly 120 as a third embodiment of the present invention. The needle assembly 120 has a structure in which a needle tip protector 122 is attached to a puncture needle body 14 in an external state.

[0077] The needle tip protector 122 is provided with a pair of side wall portions 124, 124. The side wall portion 124 is composed of a pair of leaf springs 126, 126. The pair of leaf springs 126, 126 that make up the side wall portion 124 have a leaf spring 126a which has a substantially constant thickness dimension, while the other leaf spring 126b gradually becomes thinner toward the inside in the lateral direction (left-right direction in Figure 9) which is the protruding tip side. The outer surface of the leaf spring 126b, which is the outer circumference side, is a non-inclined plane that extends substantially perpendicular to the vertical direction, and the inner surface, which is the inner circumference side, is an inclined portion 128 which inclines toward the outside in the vertical direction toward the inside in the lateral direction which is the inside in the circumferential direction.

[0078] Thus, because the inner inclined portion 128 is provided on only one of the pair of leaf springs 126a and 126b, the deformation rigidity of the pair of leaf springs 126a and 126b is different from that of the other. Therefore, when inserting the guide protrusions 30, 30 of the needle hub 18 into the slits 74, 74 of the side walls 124, 124, the guide protrusions 30, 30 can be easily inserted into the slits 74, 74 by rotating the needle hub 18 clockwise in Figure 10. That is, when the needle hub 18 is rotated clockwise in Figure 10 relative to the needle tip protector 122, the guide protrusions 30, 30 are inserted into the slits 74, 74 while deforming the relatively thin leaf spring 126b. The rotational resistance generated by the guide protrusions 30, 30 pressing against and deforming the leaf springs 126, 126 is smaller when rotating clockwise than when rotating counterclockwise. By rotating the needle hub 18 clockwise, the force required to assemble the needle hub 18 and the needle tip protector 122 can be reduced.

[0079] Furthermore, when the needle hub 18 and the needle tip protector 122 are assembled, attempting to rotate the needle hub 18 clockwise relative to the needle tip protector 122 requires the guide rib 30 to deform and overcome the relatively thick leaf spring 126a. Therefore, when rotating the needle hub 18 clockwise relative to the needle tip protector 122, a large force is required to disengage the guide rib 30 from the slit 74, making it difficult to rotate the needle hub 18. Consequently, when rotating the needle hub 18 clockwise to insert the guide rib 30 into the slit 74, the inner inclined portion 128 of one leaf spring 126a allows for easy rotation, while the other leaf spring 126b more reliably prevents over-rotation, thereby ensuring that the guide rib 30 is positioned in the slit 74.

[0080] Furthermore, for example, by providing a mechanism in the needle assembly 120 of this embodiment that prevents the relative counterclockwise rotation (reverse rotation operation) of the needle hub 18 and the needle tip protector 122, it is possible to realize a needle assembly 120 in which the needle hub 18 and the needle tip protector 122 can be easily assembled and the assembled needle hub 18 and the needle tip protector 122 are less likely to separate. As such a mechanism to prevent reverse rotation operation, a mechanism such as a ratchet can be separately provided, but for example, instead of making the inclination of the inner inclined portion 128 a smoothly continuous inclined surface as illustrated, a stepped inclined surface can be made, thereby easily allowing rotation in the direction of descending the stepped steps (clockwise rotation), while preventing rotation in the opposite direction (counterclockwise rotation) by hitting the steps.

[0081] In this embodiment, a structure in which the needle hub 18 is assembled to the needle tip protector 122 by rotating clockwise is illustrated, but a structure in which the needle hub 18 is assembled to the needle tip protector 122 by rotating counterclockwise is also possible.

[0082] Figure 11 shows a needle assembly 130 as a reference embodiment. The needle assembly 130 has a structure in which a needle tip protector 132 is attached to a puncture needle body 14 in an external state.

[0083] The needle tip protector 132 is provided with a pair of side wall portions 134, 134. The side wall portion 134 is composed of a pair of leaf springs 136, 136. The leaf spring 72 of this embodiment is provided with a projection 138 that protrudes outward in the vertical direction at the inner end in the lateral direction (left-right direction in Figure 11), which is the protruding tip side. The projection 138 has a substantially semicircular cross-section and is formed to protrude from the outer surface in the vertical direction, which is the outer peripheral surface of the leaf spring 72. The width dimension of the projection 138 decreases in the lateral direction toward the outer side in the vertical direction, which is the protruding tip, and the surface of the projection 138 has an inclined shape that slopes outward in the vertical direction toward the center in the lateral direction, and the projection 138 constitutes the outer inclined portion of this embodiment. The leaf spring 72 is partially thickened at the inner end in the lateral direction where the projection 138 is provided. Furthermore, the protruding height dimension of the guide ridges 30, 30 of the needle hub 18 inserted into the slit 74 is approximately the same as the thickness dimension of the lateral inner end of the thickened leaf spring 72.

[0084] In this embodiment, when the needle assembly 130 consists of the puncture needle body 14 and the needle tip protector 132, the guide ridges 30, 30 of the needle hub 18 are inserted into the slits 74, 74 of the side wall portions 134, 134. Furthermore, the thickness of the leaf springs 136, 136 that constitute the side wall portion 134 is thicker at the inner lateral end where the protrusion 138 is provided, and the protrusion dimension of the guide ridge 30 is approximately the same as the thickness dimension of the inner lateral end of the leaf springs 136, 136. Therefore, when a rotational force is applied to the needle hub 18 against the needle tip protector 132, the contact area between the guide ridges 30, 30 and the inner lateral ends of the leaf springs 136, 136 increases, making it difficult for the guide ridge 30 to come out of the slit 74. Therefore, the needle hub 18 and the needle tip protector 132 are easily held in a orientation that allows the tip locking portion and side wall portions 134, 134 (not shown) and the locking projection and protrusions 66, 66 (not shown) to lock in the axial direction, and a stable protective state of the needle tip (not shown) by the needle tip protector 132 is achieved.

[0085] In this embodiment, the protrusion 138 is provided to protrude from the outer surface in the vertical direction, which is the outer peripheral surface of the leaf spring 72, and to form an outward inclined portion. However, such a protrusion can also be provided to protrude from the inner surface of the leaf spring and to form an inward inclined portion. By providing the protrusion to protrude from the inner surface of the leaf spring in this way, the needle tip protector becomes less likely to rotate relative to the needle hub when assembled with the needle tip protector. As a result, it becomes easier to prevent the needle hub from coming off the needle tip protector towards the base end.

[0086] The protrusions may be provided across the entire surface of at least one of the inner and outer circumferential surfaces of the side wall portion, which is a flexible piece. The protrusions may be spot-like projections or rib-like structures with a certain length. Furthermore, by providing partial recesses in the flexible piece, the inner surface of the recesses can be used to form an inwardly inclined portion.

[0087] Figure 12 shows a needle assembly 140 as a fourth embodiment of the present invention. The needle assembly 140 has a structure in which a needle tip protector 142 is attached to a puncture needle body 14 in an external state.

[0088] The needle tip protector 142 is provided with a pair of projections 144, 144 as flexible pieces. The projections 144 project axially from the peripheral wall 50 toward the base end, similar to the projection 66 of the first embodiment. The projections 144 have an inclined portion 146 on both its lateral inner and outer surfaces, i.e., the inner circumferential surface and the outer circumferential surface, which are inclined toward the needle hub 18 toward the inner circumferential side toward the projection tip. A slit 148 is formed in the projection tip portion of the projection 144. The slit 148 has a concave cross-section that opens toward the inner surface in the lateral direction and extends axially in the longitudinal central portion of the projection 144.

[0089] In this embodiment, in addition to a pair of side wall portions 68, 68, a pair of projections 144, 144 are provided as flexible pieces with an inclined portion 146 and a slit 148 that serves as a fitting portion. Therefore, in this embodiment, four flexible pieces are provided. Furthermore, two types of flexible pieces with different shapes are provided, with the projections 144, 144 of the first flexible piece and the side wall portions 68, 68 of the second flexible piece having different shapes. The projections 144, 144 of the first flexible piece are arranged opposite each other in the lateral direction where the wide portions 60, 60 are provided, while the side wall portions 68, 68 of the second flexible piece are arranged opposite each other in the vertical direction where the narrow portions 58, 58 are provided. Thus, the flexible pieces are not necessarily limited to a pair, but may be three or more, or even just one. Also, the slit formed in the flexible piece may be a structure such as a slit 74 that penetrates the flexible piece, or a groove-like structure such as a slit 148. In this embodiment, a structure is illustrated in which flexible pieces of the same shape are provided facing each other, but the opposing flexible pieces can also be of different shapes. Furthermore, all the flexible pieces may be of the same shape, or all the flexible pieces may be of different shapes.

[0090] The needle hub 18 of the puncture needle body 14 is provided with a pair of guide ridges 30, 30 that protrude in the longitudinal direction, as well as a pair of guide ridges 150, 150 that protrude in the transverse direction. When the puncture needle body 14 is attached to the needle tip protector 142, the guide ridges 150, 150 are inserted into the slits 148, 148 of the projections 144, 144, thereby positioning the needle hub 18 and the needle tip protector 142 in the circumferential direction.

[0091] With this needle assembly 140, the rotation of the needle hub 18 is restricted not only by the locking of the side walls 68, 68 and the guide protrusions 30, 30, but also by the locking of the protrusions 144, 144 and the guide protrusions 150, 150. Therefore, the needle hub 18 is prevented from coming out of the needle tip protector 142 with greater reliability.

[0092] The protruding pieces 144, 144, which act as the first flexible pieces, restrict the movement of the needle hub 18 toward the tip side relative to the needle tip protector 142, while the side wall portions 68, 68, which act as the second flexible pieces, restrict the movement of the needle hub 18 toward the proximal end side relative to the needle tip protector 142. In this way, re-exposure of the needle tip 20 toward the tip side and re-exposure of the proximal end side are prevented by the two types of flexible pieces, respectively.

[0093] The first flexible pieces, projecting pieces 144, 144, are provided facing each other in the lateral direction, while the second flexible pieces, side wall portions 68, 68, are provided facing each other in the vertical direction. In this way, flexible pieces of the same shape are arranged facing each other in the radial direction, and two types of flexible pieces of different shapes are arranged in radial directions perpendicular to each other. Therefore, when the axial displacement of the needle hub 18 relative to the needle tip protector 142 is limited by the flexible pieces, the force exerted on the contact portion between the needle hub 18 and the needle tip protector 142 acts in a balanced manner in the circumferential direction, preventing tilting of the needle hub 18 relative to the needle tip protector 142.

[0094] In this embodiment, both the side wall portions 68, 68 and the projection pieces 144, 144 are flexible pieces with inclined portions and slits. However, for example, at least one of the inclined portions and slits may not be provided on the side wall portions 68, 68, and only the projection pieces 144, 144 may be flexible pieces.

[0095] Although embodiments of the present invention have been described in detail above, the present invention is not limited by its specific description. For example, in the above embodiments, an example was shown in which one slit is formed in one flexible piece, but multiple slits may be formed in one flexible piece.

[0096] The inner inclined portion may be inclined in both the axial and circumferential directions. Furthermore, the inclination angle of the inner inclined portion may change gradually or in steps. The same applies to the outer inclined portion.

[0097] The inner inclined portion may be provided on substantially the entire inner surface of the flexible piece, or it may be provided only on the inner surface of the flexible piece. Furthermore, the inner inclined portion may be provided at multiple locations on the inner surface of the flexible piece, in which case the multiple inner inclined portions may be inclined in different directions from each other, or they may be inclined in the same direction at different angles. The same applies to the outer inclined portion.

[0098] In the above embodiment, when assembling the needle hub 18 to the needle tip protector 10, a method was illustrated in which the needle hub 18 is rotated relative to the needle tip protector 10 in order to assemble it without the tip locking portions 26, 26 and locking projections 28, 28 of the needle hub 18 being locked to the projections 66, 66 and side wall portions 68, 68 of the needle tip protector 10. However, the needle hub 18 can also be assembled to the needle tip protector 10 without being rotated relative to the needle tip protector 10. Specifically, for example, the tip portion 22 of the needle hub 18, which has tip locking portions 26, 26 and locking projections 28, 28, is separate from the base portion 32 of the needle hub 18, and the tip portion 22 is inserted from the opening on the tip side of the needle tip protector 10 and fixed to the base portion 32 at the base end. [Explanation of Symbols]

[0099] 10, 90, 100, 112, 122, 132, 142 Needle tip protector 12,110,120,130,140 Needle assembly 14 Puncture needle 16 Puncture needle 18-needle hub 20 needle tip 22 Tip part 24 Needle fixing part 26. Tip locking part 28 Locking protrusion 30,150 Guide protrusions 32 Proximal part 34 Pipeline connection 36 connection holes 38 Bottom 40 connection ports 42 Arm 44 hooks 46 External conduit 48 Fluid flow channels 50 Peripheral wall 52 Inner bore 54 Cylindrical part 56 Enlarged section 58 Narrow part 60 Wide section 62 Interior space 64 Through-window 66,144 Projections 68,92,102,114,124,134 Side wall part (flexible piece) 70 gaps 71 Contact part 72, 94, 104, 116, 126, 136 leaf springs 74,148 Slits (fitting parts) 76,128,146 Inner inclined section 78 Wings 80 Fitting cylinder part 82 Connecting part 84 Wing body 96,118 Outer slope 138 Protrusion

Claims

1. A puncture needle with a needle hub at the proximal end, A needle assembly having a needle tip protector that is externally mounted to the needle hub and is movable in the needle axis direction from a puncture position where the puncture needle is exposed to a protective position that covers the tip of the puncture needle, The needle tip protector is provided with at least one flexible piece that allows for bending deformation in the direction intersecting the needle axis. The needle assembly comprises a flexible piece having a fitting portion that is fitted to a part of the needle hub and positioned in the circumferential direction, wherein the flexible piece on both sides in the circumferential direction constituting the fitting portion has an inclined portion on its inner surface that is inclined in the direction of the needle axis, or only one of the flexible pieces on both sides in the circumferential direction constituting the fitting portion has an inclined portion on its inner surface that is inclined in the direction intersecting the needle axis.

2. The needle assembly according to claim 1, wherein the flexible piece has a contact portion that contacts the needle hub in the needle axis direction at the protective position of the needle tip protector to prevent the needle hub from coming off the needle tip protector toward the base end.

3. The at least one of the flexible pieces has a projection that protrudes from the inner surface, The needle assembly according to claim 1 or 2, wherein the inclined portion is configured to include the protruding portion.

4. At the base end of the needle tip protector, at least one first flexible piece and at least one second flexible piece are formed as the flexible piece. The needle assembly according to any one of claims 1 to 3, wherein the first flexible piece protrudes toward the proximal end in the direction of the needle axis, and the second flexible piece protrudes toward the tip in the direction of the needle axis.

5. The needle assembly according to any one of claims 1 to 4, wherein the needle tip protector has a cylindrical peripheral wall, the outer dimensions of the peripheral wall in the direction perpendicular to the axis differ in the circumferential direction, and each pair of flexible pieces is provided facing each other in the direction perpendicular to the axis of the wide portion with a larger outer dimension and the narrow portion with a smaller outer dimension, and each pair of flexible pieces has a different shape from the others.

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