JP7603917B2 - Indwelling needle assembly - Google Patents

Description

The present invention relates to an indwelling needle assembly having a structure in which an inner needle having an inner needle hub at its base end is inserted so as to be removable through an outer needle having an outer needle hub at its base end.

Conventionally, indwelling needle assemblies used for infusion, blood collection, hemodialysis, etc. have been known. As shown in, for example, JP 2011-206609 A (Patent Document 1), an indwelling needle assembly has a structure in which an inner needle with an inner needle hub on the base end side is inserted removably into an outer needle with an outer needle hub on the base end side. With the inner needle inserted into the outer needle, the inner needle and the outer needle of the indwelling needle assembly are inserted into a blood vessel or the like of a patient, and the outer needle is placed in the blood vessel or the like by removing the inner needle from the outer needle. Then, an external flow path is connected to the outer needle hub, and infusion, blood collection, hemodialysis, etc. are performed through the lumen of the outer needle and the outer needle hub and the external flow path.

In the indwelling needle assembly, the inner needle, which has a sharp tip, is inserted into a body lumen such as a blood vessel, and the outer needle, which is fitted onto the inner needle, is inserted into the blood vessel or the like at the puncture site of the inner needle. Therefore, it is desirable to perform the puncture operation by holding the inner needle hub fixed to the inner needle.

JP 2011-206609 A

However, in practice, it has become clear that when puncturing the indwelling needle assembly, the puncturing operation may be performed by holding the outer needle hub, which is closer to the needle tip than the inner needle hub. Because the inner needle is inserted into the outer needle so that it can be removed toward the base end, there is a risk that the inner needle will move toward the base end of the outer needle when the puncturing operation is performed by holding the outer needle hub. As a result, for example, the tip of the outer needle may cover the tip of the inner needle, reducing the sharpness of the tip of the inner needle and increasing pain for the patient when puncturing.

The problem to be solved by the present invention is to provide a new indwelling needle assembly in which the movement of the inner needle relative to the outer needle is limited even when the needle is inserted by holding the outer needle hub side.

The following describes preferred embodiments for understanding the present invention. However, each embodiment described below is merely an example, and may be combined with one another as appropriate. The multiple components described in each embodiment may be recognized and used independently as far as possible, and may also be combined with any of the components described in another embodiment as appropriate. As a result, the present invention is not limited to the embodiments described below, and various alternative embodiments may be realized.

In a first aspect, in an indwelling needle assembly in which an inner needle having an inner needle hub on its base end is removably inserted into an outer needle having an outer needle hub on its base end, a clip that releasably engages with an engaging portion on the outer needle hub to connect the inner needle hub to the outer needle hub in the axial direction is formed directly on the inner needle hub and extends forward from the inner needle hub toward the outer needle hub , the clip is provided on the same top surface side as the blade surface of the needle tip of the inner needle on the inner needle hub, and a pair of lateral support surfaces that are supported by fingers when puncturing a patient are provided on both sides circumferentially away from the clip on the inner needle hub, while the engaging portion on the outer needle hub is provided on a connecting member provided on the base end side of the outer needle hub, and when an external force is applied to the clip, the clip elastically deforms and the engagement of the clip with the engaging portion is released .

According to this aspect, the amount of movement of the inner needle toward the base end relative to the outer needle is limited by the engagement between the engagement portion on the outer needle hub and the clip on the inner needle hub. Therefore, the tip of the inner needle is held in a state protruding further toward the tip side than the outer needle, and deterioration of the sharpness of the inner needle due to the outer needle catching on the tip of the inner needle is avoided. As a result, the pain inflicted on the patient during puncture can be reduced.

By providing the clip on the same top surface as the blade surface of the inner needle tip, the clip is positioned on the side opposite the patient's body surface during puncture. This allows the clip to be easily operated when releasing the clip engagement, and prevents the clip from hitting the patient's body and releasing the clip engagement unintentionally.

Since the side support surfaces that the user holds with the fingers are provided on both sides of the inner needle hub that are spaced apart from the clip in the circumferential direction, it is easy to handle and easy to puncture with the blade face of the needle tip of the inner needle positioned in the correct direction. Moreover, unintended forces are less likely to act on the clip, and it is also possible to prevent the engagement by the clip from being unintentionally released.
In addition, according to the present aspect, by providing an engagement portion on the connecting member closer to the base end than the outer needle hub, there is no need to extend the clip far toward the tip end, and the size of the inner needle hub equipped with the clip can be reduced in the axial direction.

In a second aspect, in the indwelling needle assembly described in the first aspect, the engagement portion provided on the outer needle hub is an engagement recess into which an engagement claw provided on the clip engages.

According to this aspect, the diameter of the outer needle hub does not increase at the portion where the engagement portion is formed. Furthermore, for example, if the engagement claw is engaged with the inner wall surface of the engagement recess not only in the axial direction but also in the circumferential direction, the relative rotation between the inner needle hub and the outer needle hub is restricted, and the inner needle and the outer needle can be positioned in the circumferential direction.

In a third aspect, in the indwelling needle assembly described in the first or second aspect, the clip comprises a fulcrum portion connected to the inner needle hub and protruding toward the outer periphery, an external force action piece extending from the fulcrum portion toward the base end, and an engagement piece extending from the fulcrum portion toward the tip end and equipped with an engagement claw that engages with the engagement portion on the outer needle hub side.

According to this aspect, for example, a simple operation such as pressing the external force application piece can move the engagement claw provided on the engagement piece, thereby disengaging the engagement claw from the engagement portion.

According to the present invention, the movement of the inner needle relative to the outer needle is limited even when the needle is inserted by holding the outer needle hub side.

FIG. 1 is a perspective view showing an indwelling needle assembly according to a first embodiment of the present invention; FIG. 2 is a front view of the indwelling needle assembly shown in FIG. FIG. 3 is a longitudinal sectional view of the indwelling needle assembly shown in FIG. FIG. 3 is an enlarged perspective cross-sectional view showing a main part of the indwelling needle assembly of FIG. 2, illustrating an initial state in which the inner needle is inserted into the outer needle. FIG. 3 is an enlarged perspective cross-sectional view showing a main part of the indwelling needle assembly of FIG. 2, illustrating a state in which the needle tip of the inner needle is located on the proximal side relative to the needle tip protector. FIG. 3 is an enlarged perspective cross-sectional view showing a main part of the indwelling needle assembly of FIG. 2, illustrating a state in which the needle tip protector has been separated from the outer needle hub side. FIG. 11 is a perspective view showing an indwelling needle assembly according to a second embodiment of the present invention.

The following describes an embodiment of the present invention with reference to the drawings.

Figures 1 to 3 show an indwelling needle assembly 10 according to a first embodiment of the present invention. The indwelling needle assembly 10 has a structure in which an inner needle 14 is inserted through an outer needle 12 in a manner that allows it to be removed. In the following description, the axial direction generally refers to the left-right direction in Figure 2, which is the axial direction of the outer needle 12 and the inner needle 14. The distal end side refers to the left side in Figure 2, which is the side of the needle tip 44 described below, and the proximal end side refers to the right side in Figure 2.

The outer needle 12 is a small-diameter tube made of synthetic resin or the like. The tip of the outer needle 12 is tapered so that the diameter gradually decreases toward the tip.

An outer needle hub 16 is provided on the base end side of the outer needle 12. The outer needle hub 16 is generally cylindrical, and has a structure in which the needle joint 18 and the flow path connection 20 are connected by a soft tube 22.

The needle joint 18 is made of a hard synthetic resin. The needle joint 18 is in the shape of a tapered cylinder with a smaller diameter toward the tip. The base end portion of the outer needle 12 is inserted and fitted into the inner circumference of the needle joint 18. As a result, the needle joint 18 is fixed to the base end portion of the outer needle 12, and it extends from the needle joint 18 to the tip side.

The flow path connection part 20 has a cylindrical structure with a connection part at its base end that is connected to an external flow path described later, and in this embodiment, has a structure in which a hemostasis valve 26 and a plunger 28 are housed in a cylindrical valve housing 24. The valve housing 24 is constructed by inserting the tip part of a cylindrical plunger guide 32 into the base end part of a cylindrical cover member 30, and connecting the cover member 30 and the plunger guide 32 in the axial direction. The plunger guide 32 has a base end part that extends in the axial direction with a substantially constant cross-sectional shape, and a male screw part 34 that protrudes toward the outer periphery is integrally formed at the base end.

The hemostasis valve 26 is generally disk-shaped and is made of an elastic material such as a resin elastomer or rubber. The hemostasis valve 26 has radial notches 36 formed in the center of the disk shape, and the notches 36 are opened and closed by elastic deformation of the center. The outer periphery of the hemostasis valve 26 is axially sandwiched between the tip of the plunger guide 32 and a valve support member 38 held on the inner periphery of the cover member 30. As a result, the hemostasis valve 26 is supported by the valve housing 24, and the inner cavity of the valve housing 24 is blocked by the hemostasis valve 26.

The plunger 28 is cylindrical and inserted into the inner circumference of the plunger guide 32. The plunger 28 has a base end with a substantially constant outer diameter, and the outer circumferential surface of the tip has a tapered shape that becomes smaller toward the tip.

The soft tube 22 connecting the needle joint 18 and the flow path connection part 20 is made of resin elastomer or rubber, and is capable of bending and deforming, and also allows for changes in cross-sectional shape. By providing the soft tube 22, for example, it becomes easier to connect the external flow path described below to the outer needle hub 16 while the outer needle hub 16 is fixed to the skin. The tip part of the soft tube 22 is inserted between the needle joint 18 and the outer needle 12 and fixed thereto. The base part of the soft tube 22 is inserted into the inner circumference of the tube connecting member 40 attached in an inserted state to the cover member 30 of the flow path connection part 20 and fixed thereto. As a result, the needle joint 18 and the flow path connection part 20 are connected by the soft tube 22, and the inner cavity of the needle joint 18 and the inner cavity of the flow path connection part 20 are mutually communicated through the inner cavity of the soft tube 22.

In this embodiment, the soft tube 22 has an outer diameter that is approximately constant in the axial direction, and an inner diameter that is smaller in the axial center than in both end portions. Therefore, the soft tube 22 has a thick-walled portion 41 in the axial center that is thicker than in both end portions. As a result, the inner surface of the thick-walled portion 41, which is the axial center of the soft tube 22, is located close to the outer surface 42 of the inner needle 14 when the inner needle 14 is inserted into the outer needle 12. Therefore, for example, when the soft tube 22 is pinched, the soft tube 22 is strongly pressed against the inner needle 14 at the thick-walled portion 41, and slippage between the soft tube 22 and the inner needle 14 is unlikely to occur. The soft tube 22 may have an approximately constant thickness in the axial direction, or the axial center may be thin.

The outer peripheral surface 42 of the part of the inner needle 14 that is inserted into the soft tube 22 may be provided with a non-slip surface that is less likely to slip against the inner peripheral surface of the soft tube 22, for example, by roughening the surface with unevenness or texture, or by coating with elastomer, rubber, synthetic resin, or the like that has high frictional resistance. In this way, when the soft tube 22 is grasped, slippage between the soft tube 22 and the inner needle 14 is less likely to occur, and the relative positions of the inner needle 14 and the outer needle 12 are less likely to shift. It is not necessary to provide a structure (non-slip surface) that makes the outer peripheral surface of the inner needle 14 less likely to slip against the inner peripheral surface of the soft tube 22. The non-slip surface may also be provided on the inner peripheral surface of the soft tube 22, and may be provided between the inner needle 14 and the soft tube 22, in other words, at least on one of the outer peripheral surface of the inner needle 14 and the inner peripheral surface of the soft tube 22.

The inner needle 14 is inserted from the base end into each of the inner cavities of the outer needle 12, the needle joint 18, the soft tube 22, and the flow path connection part 20. The inner needle 14 is a hollow metal needle, and has an inclined blade surface 43 at the tip end, forming an acute-angled needle tip 44. Note that in Figures 2 and 3, the blade surface 43 of the inner needle 14 is provided on the upper side in the figure.

An inner needle hub 46 is provided on the base end side of the inner needle 14. The inner needle hub 46 has a base portion 48 to which the base end portion of the inner needle 14 is fixed in an inserted state, and a connecting portion 50 is provided on the base end side of the base portion 48, and a protector housing portion 52 is provided on the tip side of the base portion 48.

The connecting part 50 is cylindrical, and the inner needle cap 54 is removably inserted and attached. The inner needle cap 54 is in a stepped cylindrical shape with a step in the middle part in the needle axial direction. The tip part of the inner needle cap 54 is provided with a ventilation filter 56. The ventilation filter 56 has the property of allowing gas to pass but not liquid to pass through, and the ventilation filter 56 is provided in the inner cavity of the inner needle cap 54 to prevent backflow blood from leaking out through the inner needle 14. If the inner needle hub 46 and the inner needle cap 54 are made transparent or semi-transparent, it is easy to confirm that the blood vessel has been punctured by backflow blood (flashback).

The protector housing 52 is cylindrical. A puncture operation section 58 is provided on the tip side of the protector housing 52. The puncture operation section 58 is generally cylindrical and has a larger diameter than the protector housing 52. The puncture operation section 58 extends from the protector housing 52 toward the tip side, and is arranged to surround the outer periphery of the base end of the flow path connection section 20 in the outer needle hub 16 when the inner needle 14 is inserted into the outer needle 12. The puncture operation section 58 may reach, for example, the outer periphery of the soft tube 22, which makes it possible to hold the inner needle hub 46 side closer to the tip side and makes it difficult to hold the soft tube 22 during puncture.

1 and 2, a pair of side support surfaces 60, 60 are provided on the outer surface of the puncture operation part 58. The side support surfaces 60 are provided on both sides corresponding to each other on the outer peripheral surface of the puncture operation part 58 and extend in the axial direction. The side support surfaces 60, 60 are provided so as to be located on both sides perpendicular to the up-down direction in the state of FIG. 2 in which the blade surface 43 of the needle tip 44 of the inner needle 14 faces upward. The side support surfaces 60, 60 do not reach the tip of the puncture operation part 58, and the tip portion is an inclined surface that inclines laterally outward toward the tip side. Since the side support surfaces 60, 60 do not reach the tip of the puncture operation part 58, the tip portion of the puncture operation part 58 is made thick, and the shape stability of the tip portion of the puncture operation part 58 is improved. In addition, each side support surface 60 may be provided with a non-slip surface such as a protrusion, a recess, or a grain, or may be a simple curved surface.

A protector housing 62 is disposed on the inner periphery of the protector housing 52. As shown in Figs. 3 and 4, the protector housing 62 includes a cylindrical housing tube 64 and a lid 66 that closes the opening at the tip end of the housing tube 64. The lid 66 has a plate-shaped portion at the tip end and a plate-shaped portion at the base end that are spaced apart from each other in the axial direction, and a needle tip protector 68 is disposed between the plate-shaped portions. The needle tip protector 68 is composed of a shielding member 70 and a fixing member 72 that are housed in the protector housing 62. The shielding member 70 and the fixing member 72 are disposed apart from each other, sandwiching the inner needle 14 in the axial direction. One of the shielding member 70 and the fixing member 72 is a magnet, and the other is a magnet or a ferromagnetic material, and a magnetic attractive force that attracts each other acts between the shielding member 70 and the fixing member 72. In this embodiment, the shielding member 70 is made of a ferromagnetic material such as metal, and the fixed member 72 is made of a permanent magnet. The fixed member 72 is fixed to the tip of the housing tube portion 64. The shielding member 70 is displaceable in a direction approaching the fixed member 72, and when the inner needle 14 is inserted between the shielding member 70 and the fixed member 72, the shielding member 70 is prevented from moving toward the fixed member 72 by the inner needle 14.

More specifically, the puncture operation part 58 has a portion that is not formed on the top surface, and has a substantially C-shaped cross section that opens upward. A clip 74 is provided between the circumferential ends of the puncture operation part 58 on the inner needle hub 46.

The clip 74 is provided on the top surface side (upper side in FIG. 2) of the inner needle hub 46, which is the same side as the blade surface 43 of the needle tip 44 of the inner needle 14. In the inner needle hub 46, lateral support surfaces 60, 60 are formed on both sides circumferentially away from the clip 74. As shown in FIGS. 1, 3, 4, etc., the clip 74 has a fulcrum portion 76 that extends upward from the tip of the puncture operation portion 58, and is integrally provided with an external force application piece 78 that extends from the protruding end of the fulcrum portion 76 toward the base end side, and an engagement piece 80 that extends from the protruding end of the fulcrum portion 76 toward the tip side.

The external force application piece 78 is a plate-like member curved in the circumferential direction. Two recesses 82, 82 are formed on the upper surface of the external force application piece 78, extending in the circumferential direction, and these recesses 82, 82 prevent the fingertips from slipping when pushing the external force application piece 78, which will be described later.

The engagement piece 80 is located between both circumferential ends of the puncture operation section 58, and like the external force application piece 78, the engagement piece 80 is formed in a plate shape that is curved in the circumferential direction. The axial length of the engagement piece 80 is greater than that of the external force application piece 78. The tip of the engagement piece 80 reaches approximately the same position in the axial direction as the tip of the puncture operation section 58. The engagement piece 80 has a through hole 83 formed in the center that penetrates in the vertical direction.

The engaging piece 80 has an engaging claw 84. The engaging claw 84 is provided on the tip side of the through hole 83 in the engaging piece 80. The engaging claw 84 protrudes downward from the engaging piece 80. The protruding dimension of the engaging claw 84 gradually increases toward the base end side. In this embodiment, the engaging claw 84 has an engaging plane 86 on the base end side that extends in the direction perpendicular to the axis, and a guide plane 87 on the tip end side that is inclined relative to the engaging plane 86, and has a substantially right-angled triangular cross section in the longitudinal section shown in FIG. 3.

When a downward force is applied to the external force application piece 78 of the clip 74, the engagement piece 80 tilts around the fulcrum 76, and the engagement claw 84 at the tip of the engagement piece 80 moves upward.

The protector housing 62 is connected to the outer needle hub 16 by a connector cap 88 serving as a connecting member. The connector cap 88 has a bottom wall portion 90 that extends in the direction perpendicular to the axis. The bottom wall portion 90 is in the shape of an annular plate, and a tubular projection 92 that protrudes toward the tip side is integrally formed at the inner peripheral end portion. A circumferential wall portion 94 that extends toward the tip side and a pair of elastic pieces 96, 96 that extend toward the base end side are integrally formed at the outer peripheral end portion of the bottom wall portion 90.

The circumferential wall portion 94 is cylindrical. An internal thread 98 is provided on the inner circumferential surface of the circumferential wall portion 94. The base end portion of the plunger guide 32 constituting the outer needle hub 16 is inserted into the inner circumference of the circumferential wall portion 94, and the male thread portion 34 of the plunger guide 32 and the female thread 98 of the circumferential wall portion 94 are screwed together, thereby attaching the connector cap 88 to the base end portion of the outer needle hub 16.

At the tip of the connector cap 88, an engagement recess 100 is formed as an engagement portion that opens to the upper surface. The engagement recess 100 is a recess that opens to the upper surface and the tip surface of the circumferential wall portion 94, and has a shape that corresponds to the engagement claw 84 provided on the clip 74 of the inner needle hub 46. In short, the engagement recess 100 allows the engagement claw 84 to be inserted from above, and the inner wall surface on the base end side of the engagement recess 100 is a plane that extends in the axial direction corresponding to the engagement plane 86 of the engagement claw 84.

The elastic pieces 96, 96 are plate-shaped and are allowed to elastically deform in the thickness direction. The elastic pieces 96, 96 are each provided with a locking protrusion 102 that protrudes toward the inner periphery at the protruding tip. The locking protrusion 102 has a tapered cross-sectional shape in which the axial width dimension decreases toward the inner periphery, which is the protruding tip. The tip portion of the protector housing 62 is inserted between the opposing elastic pieces 96, 96, and each locking protrusion 102 of the elastic pieces 96, 96 is locked in the axial direction to the protector housing 62. As a result, the connector cap 88 is attached to the protector housing 62, and the outer needle hub 16 and the protector housing 62 are connected via the connector cap 88. In addition, by pulling the protector housing 62 toward the base end, the protector housing 62 pushes the elastic pieces 96, 96 outward and climbs over the locking protrusions 102, 102, allowing the protector housing 62 and thus the needle tip protector 68 to be separated from the connector cap 88.

The puncture operation part 58 of the inner needle hub 46 is fitted onto the connector cap 88. As a result, the deformation of the elastic pieces 96, 96 toward the outer periphery is restricted by the puncture operation part 58, and the connection between the connector cap 88 and the protector housing 62 by the pair of locking projections 102, 102 is stably maintained.

The inner needle hub 46 is restricted from moving toward the base end relative to the connector cap 88 by inserting the engagement claw 84 of the clip 74 into the engagement recess 100 of the connector cap 88 and engaging with each other in the axial direction. That is, by inserting the engagement claw 84 into the engagement recess 100, the engagement plane 86 of the engagement claw 84 and the wall inner surface of the base end side of the engagement recess 100 are arranged in a position where they overlap each other in the axial projection. As a result, when the inner needle hub 46 tries to move toward the base end relative to the connector cap 88, the engagement plane 86 of the engagement claw 84 and the wall inner surface of the base end side of the engagement recess 100 are engaged, limiting the amount of relative movement of the inner needle hub 46 with respect to the connector cap 88. Therefore, the engagement between the engagement claw 84 of the clip 74 and the connector cap 88 prevents the inner needle 14 from coming off toward the base end relative to the outer needle 12. In this way, by connecting the inner needle hub 46 to the connector cap 88 attached to the base end side of the outer needle hub 16, the inner needle 14 is positioned in the axial direction relative to the outer needle 12, and movement of the inner needle 14 toward the base end side relative to the outer needle 12 is prevented.

As described above, movement of the inner needle hub 46 in the separation direction (proximal end side) relative to the outer needle hub 16 is restricted by engagement between the engagement claw 84 of the clip 74 and the inner wall surface of the engagement recess 100. Therefore, in this embodiment, the positioning portion that generates resistance to the relative movement of the outer needle hub 16 and the inner needle hub 46 in the separation direction is composed of the engagement claw 84 of the clip 74 provided on the inner needle hub 46 side and the engagement recess 100 provided on the connector cap 88 on the outer needle hub 16 side. The separation direction of the outer needle hub 16 and the inner needle hub 46 is approximately the same as the separation direction of the outer needle hub 16 and the needle tip protector 68.

When the puncture operation section 58 and the engagement piece 80 of the inner needle hub 46 are brought close to the connector cap 88 from the base end side, the guide surface 87 of the engagement claw 84 provided on the engagement piece 80 abuts against the base end of the upper elastic piece 96 of the connector cap 88 in the axial direction. As a result, when the inner needle hub 46 is further moved toward the tip side relative to the connector cap 88, the engagement claw 84 is pushed upward by the upper elastic piece 96, and the engagement claw 84 moves toward the tip side while sliding against the outer circumferential surface of the connector cap 88. Then, when the engagement claw 84 moves to the engagement recess 100 provided at the tip of the connector cap 88, the engagement claw 84 is inserted into the engagement recess 100 by the elasticity of the engagement piece 80. In this way, in this embodiment, the engagement claw 84 can be inserted into the engagement recess 100 of the connector cap 88 by moving the inner needle hub 46 from the base end side to the tip side relative to the connector cap 88 without operating the clip 74.

In this embodiment, the engagement portion provided on the connector cap 88 on the outer needle hub 16 side is a concave engagement recess 100 that opens onto the outer peripheral surface, so that the outer dimensions of the connector cap 88 can be prevented from increasing due to the formation of the engagement portion.

The engagement recess 100 is provided in the connector cap 88 that is attached to the base end side of the outer needle hub 16. Therefore, there is no need for the engagement piece 80 of the clip 74 to be long enough to reach beyond the connector cap 88 toward the tip side, and the clip 74 can be made smaller. In addition, by not having to provide the engagement recess 100 in the outer needle hub 16, the shape of the outer needle hub 16 can be designed more freely.

The engagement recess 100 is provided on the tip side of the connector cap 88. This makes the length of the engagement piece 80 longer than the external force application piece 78, and the amount of movement of the tip portion of the engagement piece 80 where the engagement claw 84 is provided is greater than the amount of movement of the external force application piece 78 due to input. Therefore, the engagement claw 84 can be moved sufficiently without significantly moving the external force application piece 78, and the insertion state of the engagement claw 84 in the engagement recess 100 can be released.

The engagement recess 100 extends in the axial direction and is provided in a portion of the circumferential direction. The engagement claw 84 inserted into the engagement recess 100 engages with the inner wall surface on the base end side of the engagement recess 100, and also engages with the inner wall surfaces on both circumferential sides of the engagement recess 100. As a result, a rotation limiting portion that positions the outer needle 12 and the inner needle 14 in the circumferential direction is formed by the engagement between the engagement claw 84 and the inner wall surface of the engagement recess 100 in the circumferential direction. In short, the outer needle 12 and the inner needle 14 are not only restricted in the movement of the inner needle 14 toward the base end side relative to the outer needle 12 by the engagement between the engagement claw 84 and the inner wall surface of the engagement recess 100, but also restricted in the relative rotation of the inner needle 14 with respect to the outer needle 12.

In the indwelling needle assembly 10 thus constructed, the inner needle 14 is inserted into a blood vessel such as the patient's arm (not shown). The medical professional (user) who inserts the blood vessel inserts the inner needle 14 into the patient's arm while holding the puncture operation part 58 of the inner needle hub 46 with his/her fingers in an appropriate position. The medical professional holds the puncture operation part 58 by pinching the sides of the puncture operation part 58 with his/her fingertips against the side support surfaces 60, 60. This allows the medical professional to stably insert the inner needle 14 into the patient from the needle tip 44. By holding the side support surfaces 60, 60 provided on the sides that are offset from the clip 74 in the circumferential direction, it is difficult for force to be applied erroneously to the clip 74 provided on the upper surface of the inner needle hub 46. This makes it possible to prevent the connection between the connector cap 88 on the outer needle hub 16 side and the clip 74 of the inner needle hub 46 from being unintentionally released.

In this way, by having a medical professional hold the puncture operation part 58 provided on the inner needle hub 46 and perform the puncture operation, the medical professional can precisely control the inner needle 14 and achieve accurate puncture.

The puncture operation unit 58 is easily held in a circumferentially positioned state because the parts of the puncture operation unit 58 that the medical staff holds with their fingertips are the side support surfaces 60, 60. In addition, the tip portions of the side support surfaces 60, 60 are inclined surfaces, so that the fingertips are less likely to slip toward the tip side of the side support surfaces 60, 60, and the force in the puncture direction can be applied more safely. In addition, the puncture operation unit 58 can be provided with a wing-like portion, which can be held for operation. The wing-like portion has a structure in which, for example, a plate-shaped connecting portion is provided protruding in the tangential direction of the fitting tube portion relative to the fitting tube portion that is attached in an externally inserted state to the puncture operation unit 58, and a wing main body is provided on each of the protruding tip ends of the connecting portions from the fitting tube portion.

By having the puncture operation part 58 provided on the inner needle 14 side, unnecessary external force is less likely to be applied to the outer needle 12 side, and unintended relative displacement of the outer needle 12 and the inner needle 14 is less likely to occur compared to when puncturing is performed by holding the outer needle hub 16. Therefore, relative movement of the outer needle 12 and the inner needle 14 due to deformation of the soft tube 22 is prevented, reducing puncture pain and achieving more accurate puncture.

However, in the outer needle hub 16 equipped with the soft tube 22, the outer needle hub 16 tends to be long because of the soft tube 22, and when attempting to puncture by grasping the inner needle 14 side, the needle tip 44 is far from the grasping position, making it difficult to position the needle tip 44, so that the user often holds the outer needle hub 16 when puncturing. When a medical professional punctures by holding the outer needle hub 16 side, which is closer to the needle tip 44 than the puncture operation part 58, the indwelling needle assembly 10 prevents the inner needle 14 from moving toward the base end side relative to the outer needle 12 due to resistance during puncturing. That is, the movement of the inner needle hub 46 toward the base end side is restricted by the clip 74 with respect to the connector cap 88 attached to the outer needle hub 16. As a result, even if puncturing is performed by holding the outer needle hub 16 side, the inner needle hub 46 does not move toward the base end side relative to the outer needle hub 16 side, and the inner needle 14 does not move toward the base end side relative to the outer needle 12. As a result, the tip 44 of the inner needle 14, which has a blade surface 43, is kept exposed further forward than the outer needle 12, preventing the sharpness of the tip 44 from decreasing, thereby reducing pain to the patient.

After the inner needle 14 and the outer needle 12 are inserted into the patient's blood vessel, the inner needle 14 is removed from the outer needle 12, leaving the outer needle 12 and the outer needle hub 16 inserted in the patient's blood vessel.

The inner needle 14 can be removed from the outer needle 12 by releasing the connection to the connector cap 88 by the clip 74. That is, by applying a downward external force to the external force application piece 78, such as by pressing the external force application piece 78 extending from the fulcrum portion 76 of the clip 74 with a fingertip, the engagement claw 84 provided on the engagement piece 80 extending from the fulcrum portion 76 to the tip side moves upward. As a result, the engagement claw 84 moves upward from the opening of the engagement recess 100 of the connector cap 88, and the movement of the inner needle hub 46 toward the base end side relative to the connector cap 88, in other words, the separation of the inner needle hub 46 from the outer needle hub 16 side is permitted without being restricted by the engagement between the engagement claw 84 and the inner wall inner surface of the base end side of the engagement recess 100. In this way, the engagement of the clip 74 to the connector cap 88 can be released by the simple operation of pushing the external force application piece 78 downward. The outer needle 12 and the outer needle hub 16, and the inner needle 14 and the inner needle hub 46 are separably assembled as described above, and after the inner needle 14 and the outer needle 12 are inserted into the patient's blood vessel, they are separated and the inner needle 14 and the inner needle hub 46 are removed.

When the inner needle 14 and the outer needle 12 are inserted into the patient's blood vessel, the clip 74 is located on the top surface (upper surface) of the indwelling needle assembly 10, which is the side opposite the patient. This allows the user to hold the side support surface 60 with the thumb and middle finger to perform the puncture operation, and then press the clip with the index finger while still holding the side support surface 60, eliminating the need to change hands or use both hands. Therefore, the operation of pushing in the clip 74 as described above and pulling out the inner needle 14 toward the base end side of the outer needle 12 can be easily performed with one hand.

As shown in Figs. 5 and 6, the needle tip 44 of the inner needle 14 that has been pulled out from the outer needle 12 is protected by the needle tip protector 68. That is, when the inner needle 14 is pulled out toward the base end, the inner needle 14 is displaced toward the base end relative to the protector housing 62 that is engaged with the connector cap 88. Then, as shown in Fig. 5, the tip of the inner needle 14 moves to the base end side beyond the shielding member 70, allowing the shielding member 70 to move closer to the fixed member 72, and the shielding member 70 is positioned to block the tip side of the inner needle 14. As a result, the movement of the inner needle 14 toward the tip side relative to the needle tip protector 68 is restricted, and the needle tip 44 of the inner needle 14 housed in the protector housing 62 is not exposed to the outside.

Furthermore, a protrusion (not shown) provided on the inner needle 14 is engaged in the axial direction with the base end of the accommodating tube portion 64 of the protector housing 62, thereby transmitting a pulling force from the inner needle 14 to the protector housing 62. Then, the protector housing 62 is pulled toward the base end relative to the connector cap 88, whereby the engagement between the protector housing 62 and the engaging protrusion 102 of the connector cap 88 is released, and the protector housing 62 is separated from the connector cap 88 as shown in FIG. 6. This causes the inner needle 14 to be separated from the outer needle 12 and removed.

The outer needle 12, which has been separated from the inner needle 14 and placed in place, has the connector cap 88 removed from the outer needle hub 16, and a connector for a tube or syringe (not shown) constituting an external flow path is attached to the male thread portion 34 provided on the flow path connection portion 20 of the outer needle hub 16. This connects the inner cavity of the outer needle 12 and the outer needle hub 16 to the external flow path. In this way, the male thread portion 34 of the outer needle hub 16 is used both to connect the connector cap 88 to the outer needle hub 16 and to connect the external flow path to the outer needle hub 16.

The protector housing 62 may be fixed to the connector cap 88, and the inner needle 14 and the protector housing 62 may be positioned in the circumferential direction. In this case, by rotating the inner needle 14 and the inner needle hub 46, the rotational force is transmitted to the connector cap 88 via the protector housing 62, and the connector cap 88 is removed from the outer needle hub 16. The protector housing 62 and the connector cap 88 may be fixed separately, but may be integrated.

When an external flow path (not shown) is connected to the outer needle hub 16, the plunger 28 is pushed toward the tip side by the external flow path. The pushed plunger 28 is pressed against the hemostasis valve 26, deforming the hemostasis valve 26 and opening the notch 36 in the hemostasis valve 26. This connects the patient's blood vessel to the external flow path through the inner cavity of the outer needle 12 and the outer needle hub 16, allowing treatment such as hemodialysis, blood sampling, and administration of medicinal fluids to be performed.

Figure 7 shows an indwelling needle assembly 110 as a second embodiment of the present invention. In the following description, the same components and parts as those in the first embodiment are denoted by the same reference numerals in the figure and will not be described.

The indwelling needle assembly 110 has an outer needle hub 112 which is entirely formed from a hard synthetic resin and does not include a soft tube 22.

In addition, an engagement portion (not shown) is provided on the outer peripheral surface of the outer needle hub 112, and the clip 74 of the inner needle hub 46 engages with the outer needle hub 112 without the intervention of another member. The engagement portion provided on the outer needle hub 112 may be an engagement recess 100 as in the above embodiment, or may be an engagement protrusion that protrudes from the outer peripheral surface.

Although the embodiments of the present invention have been described above in detail, the present invention is not limited to the specific description. For example, the engagement recess 100 may extend in the circumferential direction around the entire circumference, and the configuration of the above embodiment in which the outer needle 12 and the inner needle 14 are positioned in the circumferential direction by the engagement between the engagement claw 84 and the inner wall surface of the engagement recess 100 is not essential.

The needle tip protector 68 is not required, and the connector cap 88 that connects the outer needle hub 16 and the protector housing 62 may also be omitted.

For example, the connector cap and protector housing may be structured so that they do not separate when the inner needle is pulled out, and the connector cap and outer needle hub may be structured so that they separate when the inner needle is pulled out, so that the connector cap can be separated from the outer needle hub together with the inner needle. In this case, since the fixing force between the outer needle hub and the connector cap is small and positioning is likely to be insufficient, it is desirable for the clip to engage with a member other than the outer needle hub or the connector cap fixed to the outer needle hub.

The surface that abuts and engages with the engaging claw in the axial direction of the engaging portion may be inclined and extend in the direction perpendicular to the axis.

The clip 74 may be separate from the protector housing 52 and the puncture operation section 58, and may be made of a different material, for example. The specific structure of the clip is not particularly limited. For example, when the external force acting on the external force acting piece 78 of the clip 74 in the above embodiment is released, the clip 74 returns to its initial shape based on the elasticity of the fulcrum 76, etc., but the return of the clip 74 to its initial shape can be assisted by the elasticity of the spring, for example, by providing a spring between the external force acting piece 78 and the protector housing 52. It is also possible to adopt a clip in which a separate clip is supported by a pin and swung, or a locking claw that is retracted and moved inward by a pressing operation is locked in an engagement recess provided on the inner circumferential surface. In particular, in the embodiment with a soft tube such as the first embodiment, at least one clip may be provided on the side surface or bottom surface instead of or in addition to the top surface, and it is also possible to provide a pair of clips that are engaged with engagement portions provided on the outer needle hub side on both sides, for example. In addition, the portion of the clip 74 to which the operating force is applied may have a structure such as the external force application piece 78, or may be designed so that the clip is held in a disengaged state without the need to continue applying an external force to the clip, or the clip may be designed so that the engaged and disengaged states can be switched multiple times by operating a button.

The clip 74 may be provided on the outer periphery of the needle tip protector 68 and the connector cap 88 to prevent separation of the needle tip protector 68 and the connector cap 88. The clip 74 may also be provided on the outer periphery of the needle tip protector 68 and the outer needle hub 16 to prevent separation of the needle tip protector 68 and the outer needle hub 16.

In the above embodiment, a connector cap 88 is provided at the base end of the outer needle hub 16 to cover the base end of the outer needle hub 16, and the connector cap 88 is used as a connecting member, but the outer needle hub 16 and the needle tip protector 68 may be assembled without providing the connector cap 88. In this case, the clip 74 may be provided, for example, so as to be releasably engaged with the needle tip protector 68.

In the above embodiment, the positioning portion that generates a resistance against the relative movement of the outer needle hub 16 and the inner needle hub 46 in the separation direction is constituted by the engagement claw 84 of the clip 74 and the engagement recess 100 of the connector cap 88, but the structure of the positioning portion is not limited to the specific example of the above embodiment. For example, the inner needle hub 46 may have a tubular portion (corresponding to the puncture operation portion 58) that is inserted into the connector cap 88, and the positioning portion may be constituted by the axial engagement of a convex portion protruding from the inner peripheral surface of the tubular portion and a convex portion protruding from the outer peripheral surface of the connector cap 88. In this case, the convex portion of the tubular portion and the convex portion of the connector cap 88 may be provided continuously around the entire circumference, or may be provided partially in the circumferential direction. When the convex portions are provided partially in the circumferential direction, for example, the inner needle hub 46 and the outer needle hub 16 are assembled in a circumferential orientation in which the convex portions do not interfere with each other, and then the inner needle hub 46 and the outer needle hub 16 are rotated to move the convex portions to a position where they engage in the axial direction, thereby facilitating the task of assembling the inner needle hub 46 and the outer needle hub 16 while providing a positioning portion.

As another embodiment of the positioning portion, for example, the cylindrical portion of the inner needle hub 46 can be fitted into the connector cap 88, and the frictional resistance acting between the cylindrical portion of the inner needle hub 46 and the connector cap 88 can be utilized. As yet another embodiment of the positioning portion, for example, a convex portion protruding from the outer circumferential surface of the connector cap 88 can be fitted into a slit portion formed in the cylindrical portion of the inner needle hub 46 that is inserted into the connector cap 88, and the frictional resistance acting between the convex portion and the inner surface of the slit portion can be utilized. As yet another embodiment of the positioning portion, for example, a rubber-like body such as a rubber valve through which the inner needle 14 penetrates and which contacts the outer circumferential surface of the inner needle 14 can be provided separately from the hemostatic valve 26, and the inner needle hub 46 and the outer needle hub 16 can be positioned using the frictional resistance acting between the rubber-like body and the inner needle 14.

Furthermore, the positioning of the outer needle hub 16 and the inner needle hub 46 by the positioning portion may be released simply by pulling the inner needle hub 46 toward the base end relative to the outer needle hub 16 with a force greater than the resistance exerted by the positioning portion, without requiring any special operation such as pressing the external force application piece 78 of the clip 74.
Furthermore, the present invention originally includes each of the inventions described in (i) to (viii) below, and the configurations and effects thereof will be described below.
The present invention relates to
(i) An indwelling needle assembly in which an inner needle having an inner needle hub on its base end is removably inserted into an outer needle having an outer needle hub on its base end, the inner needle hub being provided with a clip that is releasably engaged with an engaging portion on the outer needle hub, the clip being provided on the same top surface side as the blade surface of the needle tip of the inner needle on the inner needle hub, and a pair of lateral support surfaces that are supported by fingers are provided on both sides of the inner needle hub circumferentially spaced from the clip;
(ii) An indwelling needle assembly in which an inner needle having an inner needle hub on its base end is inserted removably into an outer needle having an outer needle hub on its base end, the outer needle hub comprising a needle joint portion to which the outer needle is fixed, a flow path connection portion connected to an external flow path, and a soft tube connecting the needle joint portion and the flow path connection portion, and the inner needle hub is provided with a clip that is releasably engaged with an engagement portion provided on the outer needle hub;
(iii) The indwelling needle assembly according to (i) or (ii), wherein the engagement portion is provided on a connecting member attached to a base end side of the outer needle hub.
(iv) An indwelling needle assembly in which an inner needle having an inner needle hub on its base end side is removably inserted into an outer needle having an outer needle hub on its base end side, the inner needle hub is provided with a clip that is releasably engaged with an engaging portion provided on the outer needle hub side, a needle tip protector is provided that covers the tip of the inner needle when the inner needle is pulled out from the outer needle to the base end side, and a connecting member that detachably connects the needle tip protector to the outer needle hub is provided on the base end side of the outer needle hub, and the engaging portion is provided on the connecting member.
(v) The indwelling needle assembly according to any one of (i) to (iv), wherein the engaging portion provided on the outer needle hub side is an engaging recess with which an engaging claw provided on the clip engages.
(vi) The indwelling needle assembly according to any one of (i) to (v), wherein the clip comprises a fulcrum portion connected to the inner needle hub and protruding outwardly, an external force application piece extending from the fulcrum portion toward the base end side, and an engagement piece extending from the fulcrum portion toward the tip end side and having an engagement claw that engages with the engagement portion on the outer needle hub side.
(vii) An indwelling needle assembly in which an inner needle having an inner needle hub on its base end is inserted removably into an outer needle having an outer needle hub on its base end, the outer needle hub comprising a needle joint to which the outer needle is fixed, a flow path connection part connected to an external flow path, and a soft tube connecting the needle joint part and the flow path connection part, and an anti-slip device is provided between the outer peripheral surface of the insertion part of the inner needle into the soft tube and the inner peripheral surface of the soft tube;
(viii) An indwelling needle assembly in which an inner needle having an inner needle hub on its base end side is removably inserted into an outer needle having an outer needle hub on its base end side, wherein a needle tip protector is provided which covers the tip of the inner needle when the inner needle is pulled out from the outer needle to the base end side, a connecting member is provided on the base end side of the outer needle hub which detachably connects the needle tip protector to the outer needle hub, and a positioning portion is provided which generates a resistance against relative movement between the connecting member and the inner needle hub in the direction of separation of the needle tip protector and the outer needle hub;
This includes inventions relating to.
In the invention described in (i) above, the engagement between the engaging portion on the outer needle hub and the clip on the inner needle hub limits the amount of movement of the inner needle toward the base end side relative to the outer needle. Therefore, the tip of the inner needle is held in a state protruding further toward the tip side than the outer needle, and the deterioration of the sharpness of the inner needle due to the outer needle hitting the tip of the inner needle is avoided. As a result, the pain given to the patient at the time of puncture can be suppressed. Since the clip is provided on the same top surface side as the blade surface of the needle tip of the inner needle, the clip is located on the opposite side to the patient's body surface at the time of puncture. Therefore, the clip can be easily operated when releasing the engagement by the clip, and it is possible to prevent the engagement by the clip from being unintentionally released by the clip hitting the patient's body. Since the lateral support surfaces that the user holds with the fingers are provided on both sides of the clip circumferentially off of the clip on the inner needle hub, it is easy to handle with the blade surface of the needle tip of the inner needle positioned, and puncture is easy. Moreover, it is difficult for unintended forces to act on the clip, and it is also possible to prevent the engagement by the clip from being unintentionally released.
In the invention described in (ii) above, since the outer needle hub is provided with a soft tube, for example, when connecting an external flow path to the flow path connecting part while the outer needle is punctured into a blood vessel or the like, the soft tube can be bent to easily connect the flow path connecting part to the external flow path. The engagement between the engagement part on the outer needle hub and the clip on the inner needle hub limits the amount of movement of the inner needle toward the base end side relative to the outer needle. Therefore, the tip of the inner needle is held in a state protruding further toward the tip side than the outer needle, and deterioration of the sharpness of the inner needle is avoided, so that pain inflicted on the patient at the time of puncture can be suppressed. The indwelling needle assembly targeted by this embodiment is provided with a soft tube, so that the outer needle hub is likely to be long, and when an attempt is made to grasp and puncture the inner needle hub, the needle tip is far from the grasping position, making it difficult to position the needle tip, and therefore, statistical information has been obtained that there are an increasing number of cases in which the outer needle hub is held during puncture. Here, in the indwelling needle assembly of this aspect, the relative movement of the inner needle and the outer needle is prevented by the engagement of the clip, so that even if the outer needle hub is held during puncture, the outer needle will not move toward the distal end relative to the inner needle, causing the tip of the inner needle to be covered by the outer needle. Therefore, it is possible to satisfactorily handle stable puncture performed by holding the needle joint close to the needle tip, for example.
In the invention described in (iii) above, an engagement portion is provided on the connecting member located on the base end side of the outer needle hub, so that there is no need to extend the clip far toward the tip side, and the size of the inner needle hub equipped with the clip can be reduced in the axial direction.
In the invention described in (iv) above, the amount of movement of the inner needle toward the base end side relative to the outer needle is limited by the engagement between the engagement part on the outer needle hub and the clip on the inner needle hub. Therefore, the tip of the inner needle is held in a state protruding toward the tip side from the outer needle, and deterioration of the sharpness of the inner needle is avoided, so that pain inflicted on the patient at the time of puncture can be suppressed. Since the engagement part that engages with the clip is provided on the connecting member that connects the outer needle hub and the needle tip protector at the base end side of the outer needle hub, the extension length of the clip toward the tip side can be shortened compared to when the clip is engaged with the outer needle hub, and the inner needle hub equipped with the clip can be made smaller in the axial direction.
In the invention described in (v) above, the diameter of the outer needle hub side does not increase at the portion where the engagement portion is formed. Furthermore, for example, if the engagement claws are made to engage with the inner wall surface of the engagement recess not only in the axial direction but also in the circumferential direction, the relative rotation between the inner needle hub and the outer needle hub side is restricted, and the inner needle and the outer needle can be positioned in the circumferential direction.
In the invention described in (vi) above, for example, by a simple operation such as pressing the external force acting piece, the engagement claw provided on the engagement piece can be moved to release the engagement of the engagement claw with the engagement portion.
In the invention described in (vii) above, for example, when the soft tube is pinched during puncture and the inner peripheral surface of the soft tube, which has been crushed by the fingers, comes into contact with the outer peripheral surface of the inner needle, the anti-slip provided between the inner peripheral surface of the soft tube and the outer peripheral surface of the inner needle makes it difficult for the soft tube to slip relative to the inner needle. Therefore, it is possible to make it difficult for the relative positions of the inner needle and the outer needle in the axial direction to shift. The anti-slip is preferably provided by roughening the outer peripheral surface of the inner needle or forming irregularities. According to this, when the soft tube is pressed against the anti-slip of the inner needle, the inner peripheral portion of the soft tube deforms along the irregularities of the anti-slip of the inner needle, so that the soft tube is mechanically locked in the axial direction against the irregularities of the anti-slip, and the soft tube becomes less likely to slip in the axial direction relative to the inner needle due to the anchor effect.
In the invention described in (viii) above, unintended relative movement between the outer needle hub and the inner needle hub is prevented by the resistance force exerted by the positioning portion, so that it is possible to prevent the inner needle from moving toward the base end side relative to the outer needle and the needle tip of the inner needle from being covered by the outer needle. This avoids deterioration of the sharpness of the inner needle, and reduces pain to the patient when puncturing. In addition, because unintended relative movement between the connecting member and the inner needle hub in the separation direction is prevented by the positioning portion, unnecessary movement of the needle tip protector relative to the inner needle is also prevented.

10 Indwelling needle assembly (first embodiment)
12 outer needle 14 inner needle 16 outer needle hub 18 needle joint portion 20 flow path connection portion 22 soft tube 24 valve housing 26 hemostatic valve 28 plunger 30 cover member 32 plunger guide 34 male thread portion 36 notch 38 valve support member 40 tube connecting member 41 thick portion 42 outer circumferential surface 43 blade surface 44 needle tip 46 inner needle hub 48 base portion 50 connecting portion 52 protector housing portion 54 inner needle cap 56 ventilation filter 58 puncture operation portion 60 side support surface 62 protector housing 64 housing tube portion 66 cover body 68 needle tip protector 70 shielding member 72 fixing member 74 clip 76 fulcrum portion 78 external force application piece 80 engagement piece 82 recess 83 through hole 84 engagement claw (positioning portion)
86 Engagement plane 87 Guide surface 88 Connector cap (connecting member)
90 Bottom wall portion 92 Tubular projection 94 Circumferential wall portion 96 Elastic piece 98 Female thread 100 Engagement recess (engagement portion, positioning portion)
102 Locking protrusion 110 Indwelling needle assembly (second embodiment)
112 Outer needle hub

Claims (3)

In an indwelling needle assembly in which an inner needle having an inner needle hub on a proximal end side is inserted removably into an outer needle having an outer needle hub on a proximal end side,
a clip which is releasably engaged with an engaging portion on the outer needle hub to connect the inner needle hub to the outer needle hub in the axial direction is formed directly on the inner needle hub and extends forward from the inner needle hub toward the outer needle hub , the clip is provided on the same top surface side as the blade surface of the needle tip of the inner needle in the inner needle hub,
A pair of side support surfaces are provided on both sides of the inner needle hub that are spaced apart from the clip in the circumferential direction, and are supported by fingers when the needle is inserted into a patient .
the engaging portion on the outer needle hub side is provided on a connecting member provided on the base end side of the outer needle hub,
In the indwelling needle assembly, application of an external force to the clip causes the clip to elastically deform and release the engagement of the clip with the engaging portion . The indwelling needle assembly according to claim 1 , wherein the engaging portion provided on the outer needle hub is an engaging recess with which an engaging claw provided on the clip engages. The retention needle assembly according to claim 1 or 2, wherein the clip comprises a fulcrum portion connected to the inner needle hub and protruding toward the outer periphery, an external force application piece extending from the fulcrum portion toward the base end, and an engagement piece extending from the fulcrum portion toward the tip end and having an engagement claw that engages with the engagement portion on the outer needle hub side.

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