Needle tip protector

Abstract

Provided is a needle tip protector that has a new structure and that exhibits effects such as suppression of contact pressure with a puncture needle, an outer needle hub, or the like.　A needle tip protector 10 prevents exposure of a needle tip 38 by moving to the tip-end side of the needle tip 38 of a puncture needle 34, and is configured such that: base end sides of a pair of lateral plate parts 50, 52 that extend along the puncture needle 34 are mutually connected by a bottom part 48; in a state of being mounted to the puncture needle 34, the puncture needle 34 that is inserted through a needle insertion hole 54 of the bottom part 48 is inserted in between the lateral plate parts 50, 52; the lateral plate parts 50, 52 are elastically deformed toward isolating sides; needle tip cover parts 76, 110 that project toward the inner side in the facing direction of the lateral plate parts 50, 52 are provided on the tip-end sides of the lateral plate parts 50, 52; the lateral plate parts 50, 52 are respectively set to have a width dimension of 70% or less of the width dimension of the needle tip cover parts 76, 110; and narrow width parts 66, 100 that can be flexibly deformed are set to have a length dimension of 50% or more of the length dimension of the lateral plate parts 50, 52 provided with the narrow width parts 66, 100.

Description

Needle tip protector

[0001] The present invention relates to a needle tip protector that protects the tip of a puncture needle after use.

[0002] Needle tip protectors that are attached to a puncture needle and move toward the needle tip to protect the needle tip after use have been known. The applicant has disclosed a needle tip protector in, for example, U.S. Patent No. 4,929,241 (Patent Document 1). The needle tip protector in Patent Document 1 has a pair of side plates extending from a bottom portion having an insertion hole for the puncture needle toward the needle tip, and the tip portions of the pair of side plates approach each other to form a needle tip cover that covers the needle tip.

[0003] U.S. Pat. No. 4,929,241

[0004] However, as a result of further investigation by the inventor into the needle tip protector of Patent Document 1, it became clear that there was still room for improvement.

[0005] For example, in the needle tip protector of Patent Document 1, when the needle tip protector moves toward the tip of the puncture needle, the needle tip cover portion constituting the needle tip shield of the needle tip protector slides against the outer peripheral surface of the puncture needle, but it has been revealed that this sliding resistance is relatively large, and a large force is required to pull out the puncture needle. In particular, when a protrusion that engages with the bottom of the needle tip protector is provided on the outer peripheral surface of the tip of the puncture needle, resistance is large when the needle tip cover portion of the needle tip protector moves over the protrusion, so it was necessary to further reduce the force required for pulling out the puncture needle in order to make it easier to pull out the puncture needle.

[0006] Furthermore, when inserting the needle tip protector attached to the puncture needle into the inner circumference of the outer needle hub, the needle tip protector comes into sliding contact with the inner surface of the outer needle hub, which may make it difficult to insert the needle tip protector into the outer needle hub due to sliding resistance, or it may be possible for the inner surface of the outer needle hub to be damaged, such as being scraped off by the sliding contact of the needle tip protector.

[0007] Furthermore, for example, when a plurality of individual needle tip protectors are stored and transported in a package such as a bottle, the tip portion of one needle tip protector may get caught between a pair of opposing side plates of another needle tip protector, causing a problem that an operator must manually release the engagement of the plurality of needle tip protectors, making the work complicated.

[0008] Furthermore, the needle insertion hole formed in the bottom of the needle tip protector must be large enough to allow the puncture needle to pass through and to allow the tiny protrusion at the tip of the puncture needle to be engaged, so it is made slightly larger than the outer diameter of the puncture needle. Therefore, high precision is required to align the puncture needle with the needle insertion hole when inserting the puncture needle into the needle insertion hole, making the insertion process very difficult.

[0009] Furthermore, when the needle tip protector is attached to the puncture needle, the pair of side plate portions both extend approximately parallel to the needle axis, and therefore the width dimension in the opposing direction of the pair of side plate portions is relatively large at the proximal end portion. Therefore, for example, when the inner needle hub is inserted into the outer needle hub on the outer periphery of the proximal end portion of the needle tip protector, the inner needle hub is likely to interfere with the proximal end portion of the needle tip protector.

[0010] An object of the present invention is to provide a needle tip protector with a novel structure that can solve at least one of the problems of the needle tip protector described above.

[0011] The following describes preferred embodiments for understanding the present invention, but the embodiments described below are merely examples and may be appropriately combined with one another. Multiple components described in each embodiment may be recognized and employed independently to the greatest extent possible, and may also be appropriately combined with any of the components described in other embodiments. Accordingly, the present invention is not limited to the embodiments described below, and various other embodiments may be realized.

[0012] In a first aspect, a needle tip protector is attached to a puncture needle and prevents exposure of the needle tip by moving toward the tip end where the needle tip is located. The needle tip protector has a pair of side plate portions extending along the puncture needle on both sides of the puncture needle, and a bottom portion connecting the base ends of the pair of side plate portions to each other. When attached to the puncture needle, the puncture needle is inserted through a needle insertion hole that penetrates the bottom portion, and the puncture needle is inserted between the pair of side plate portions, so that the pair of side plate portions elastically deform toward each other and move away from each other. A needle tip cover portion is provided on the tip side of each side plate portion, protruding toward the inside in the opposing direction of the pair of side plate portions. Each side plate portion has a narrow width portion that is 70% or less of the maximum width dimension of the needle tip cover portion and is capable of flexibly deforming in the opposing direction of the pair of side plate portions, and the length dimension of the narrow width portion is 50% or more of the length dimension of the side plate portion comprising the narrow width portion.

[0013] In the needle tip protector constructed according to this aspect, the narrow portions, which are narrower than the needle tip cover portions, are provided on the side plates with a sufficient length, making the side plates more susceptible to flexural deformation at the narrow portions, thereby reducing the contact pressure of the needle tip cover portions on the pair of side plates against the puncture needle. Therefore, for example, when the needle tip protector moves toward the tip of the puncture needle as the puncture needle is withdrawn, the resistance caused by the sliding contact between the needle tip cover portions provided at the distal ends of the side plates and the puncture needle is reduced, allowing the puncture needle to be withdrawn with less force. As can be seen from the above, the narrow portions are low-rigidity portions in which the deformation rigidity (flexural deformation rigidity) in the plate thickness direction is reduced due to their narrow width, making them flexurally deformable. For example, if the needle tip protector is provided with a side cover piece formed by bending the side plate portion on the outside in the width direction and covering the side of the puncture needle, the connection portion between the side plate portion and the side cover piece does not fall under the narrow width portion because the bending deformation rigidity is high due to the formation of the side cover portion and flexural deformation in the opposing direction of the pair of side plate portions is limited.

[0014] In the side plates extending along the puncture needle on both sides of the puncture needle, the narrow portions are preferably located in the widthwise middle of the side plates. Specifically, for example, the widthwise both sides of the side plates are located closer to the widthwise center than the widthwise both sides of the bottom, thereby forming the narrow portions located in the widthwise middle of the side plates.

[0015] In the second aspect, in the needle tip protector described in the first aspect, the length dimension of each needle tip cover part is 50% or more of the maximum width dimension of the needle tip cover part, and when attached to the puncture needle, the angle formed by the straight line connecting the point located outermost in the opposing direction of the pair of side plate parts on the needle tip cover part and the contact point with the puncture needle and the needle axis of the puncture needle is 60 degrees or less.

[0016] With a needle tip protector constructed according to this aspect, the length of the needle tip cover part is long, and the angle that the straight line connecting the outermost diameter point of the needle tip cover part in the attached state and the point of contact with the puncture needle makes with the needle axial direction is 60 degrees or less. This reduces the external force on the puncture needle in the direction perpendicular to the axial direction due to the elastic force of the needle tip protector, thereby reducing sliding resistance when the puncture needle is withdrawn. Furthermore, when the needle tip protector attached to the puncture needle is inserted into the inner circumference of an outer needle hub or the like, displacement of the needle tip cover part makes it difficult for the needle tip protector to be pressed strongly against the inner circumference of the outer needle hub or the like, and damage to the inner circumference of the outer needle hub or the like due to the pressing of the needle tip protector is also prevented.

[0017] In a third aspect, in the needle tip protector described in the first or second aspect, the pair of side plate portions are each formed with a side cover piece that protrudes inward in the opposing direction at one of the widthwise edge portions on opposite sides of the plate width direction, and the connection width dimension of the connection portion between the side cover piece and the widthwise edge portion of the side plate portion is 70% or less of the maximum width dimension of the side cover piece in the direction parallel to the connection width dimension.

[0018] According to the needle tip protector constructed in accordance with this aspect, the side cover pieces prevent the puncture needle from being exposed to the sides, thereby further enhancing the needle tip protection function.

[0019] In addition, by limiting the width dimension of the connection portion between the widthwise edge portion of the side plate portion and the side cover piece, the reinforcing effect of the side cover piece on the side plate portion is suppressed, and bending deformation of the side plate portion is more easily tolerated, which makes it easier to pull out the puncture needle, easier to insert into an outer needle hub, etc., and avoids damage to the outer needle hub, etc.

[0020] A fourth aspect is a needle tip protector that is attached to a puncture needle and moves to the distal end side where the needle tip is located to prevent the needle tip from being exposed, and includes a pair of side plate portions that extend along the puncture needle on both sides of the puncture needle, and a bottom portion that interconnects the base end sides of the pair of side plate portions. When attached to the puncture needle, the puncture needle is inserted through a needle insertion hole that penetrates the bottom portion, and the puncture needle is inserted between the pair of side plate portions, and moves to the side where the pair of side plate portions are separated from each other. The needle tip cover is elastically deformed, and a needle tip cover portion is provided on the tip side of each side plate portion, protruding inward in the opposing direction of the pair of side plate portions.The length dimension of each needle tip cover portion is 50% or more of the maximum width dimension of the needle tip cover portion, and when attached to the puncture needle, the angle between the needle axis of the puncture needle and a straight line connecting the outermost point on the needle tip cover portion in the opposing direction of the pair of side plate portions and the point of contact with the puncture needle is 60 degrees or less.

[0021] With a needle tip protector constructed according to this aspect, the length of the needle tip cover part is long, and the angle formed by the line connecting the outermost diameter point of the needle tip cover part in the attached state and the point of contact with the puncture needle is 60 degrees or less, so that the external force perpendicular to the axis of the puncture needle due to the elastic force of the needle tip protector can be reduced, and sliding resistance when the puncture needle is withdrawn can be reduced. Furthermore, for example, when the needle tip protector attached to the puncture needle is inserted into the inner circumference of an outer needle hub, etc., displacement of the needle tip cover part makes it difficult for the needle tip protector to be pressed strongly against the inner surface of the outer needle hub, etc., and damage to the inner surface of the outer needle hub, etc. due to the pressing of the needle tip protector is also prevented.

[0022] A fifth aspect is a needle tip protector described in any one of the first to fourth aspects, wherein the positions of the base ends of the pair of needle tip cover parts are different from each other in the needle axis direction of the puncture needle.

[0023] With a needle tip protector constructed according to this aspect, the positions of the base ends of the needle tip covers are made different from each other, thereby increasing the degree of freedom in designing the shape including the needle tip covers. This makes it easy to adjust, for example, the length of each needle tip cover, the needle tip protection form that covers the needle tip, and the engagement of the needle tip cover with the outer needle hub. Furthermore, for example, when the needle tip covers extend distally while inclining toward the puncture needle, the positions of the base ends of the needle tip covers are different in the needle axial direction, making it easier to position the distal position of one needle tip cover more distally relative to the distal position of the other needle tip cover. As a result, in the needle tip protection state, one needle tip cover overlaps the other needle tip cover with a larger overlap, achieving more stable protection of the needle tip.

[0024] In a sixth aspect, in the needle tip protector described in the fifth aspect, an outer needle hub provided on the base end side of the outer needle that is extrapolated onto the puncture needle is provided with a concave accommodating portion that accommodates the pair of needle tip cover portions, and the base ends of the pair of needle tip cover portions are both located on the straight inner surface of the accommodating portion.

[0025] According to this aspect, even if the needle tip protector has a structure in which the base ends of a pair of needle tip cover parts are arranged at different positions in the needle axial direction, the base ends of both needle tip cover parts are positioned on the straight inner surface of the accommodating part of the outer needle hub, so that, for example, only one needle tip cover part is not pressed hard against the outer needle hub, and the needle tip protector can be stably accommodated in the accommodating part of the outer needle hub.

[0026] A seventh aspect is a needle tip protector that is attached to a puncture needle and prevents exposure of the needle tip by moving toward the tip end where the needle tip is located, and has a pair of side plate portions that extend along the puncture needle on both sides of the puncture needle, and when attached to the puncture needle, the puncture needle is inserted between the pair of side plate portions and the pair of side plate portions elastically deform toward each other, and a needle tip cover portion is provided on the tip end of each side plate portion that protrudes inward in the opposing direction of the pair of side plate portions, and when in a standalone state not attached to the puncture needle, the distance between the opposing surfaces of the pair of side plate portions is large enough that the needle tip cover portion cannot fit inside in its initial shape.

[0027] The needle tip cover portion that covers the needle tip is likely to have a step formed in order to achieve a shape that enables effective needle tip protection. Therefore, if the needle tip cover portion gets caught between the opposing surfaces of a pair of side plates of another needle tip protector, the step can get caught on the side plates, making it difficult to separate. Therefore, in a needle tip protector structured according to this aspect, the distance between the opposing surfaces of the pair of side plates is large enough that the needle tip cover portion cannot get caught between the opposing surfaces of the pair of side plates of another needle tip protector in its initial shape. This makes it difficult for the needle tip cover portion, which is the tip portion of the needle tip protector, to get caught between the opposing surfaces of the pair of side plates of another needle tip protector, for example, when multiple needle tip protectors are individually bottled for storage or transportation. This prevents multiple needle tip protectors housed in a single container from fitting together, reducing the effort required to unfit the needle tip protectors.

[0028] The eighth aspect is a needle tip protector that is attached to a puncture needle and prevents exposure of the needle tip by moving toward the tip end where the needle tip is located, and has a pair of side plate portions that extend along the puncture needle on both sides of the puncture needle, and a bottom portion that connects the base end sides of the pair of side plate portions to each other, and when attached to the puncture needle, the puncture needle is inserted through a needle insertion hole that passes through the bottom portion, and the puncture needle is inserted between the pair of side plate portions, and the pair of side plate portions are elastically deformed toward sides that move away from each other, and when in a standalone state not attached to the puncture needle, the relative inclination angle of the base end portions of the pair of side plate portions is smaller than the relative inclination angle of the tip end portions of the pair of side plate portions.

[0029] A needle tip protector constructed according to this aspect improves the ease of assembly of the needle tip protector to the outer needle hub and reduces its size. That is, for example, if an engagement portion for the needle tip protector is provided on the inner peripheral surface of the outer needle hub, and the side plate portions are extended to the tip at a constant angle without increasing the width of the bottom (the distance between the opposing base ends of the pair of side plate portions) when assembling the needle tip protector to the outer needle hub, the side plate portions may bend due to the stress generated when the needle tip protector overcomes the engagement portion of the outer needle hub and come into contact with the puncture needle, potentially reducing the ease of assembly of the needle tip protector to the outer needle hub. On the other hand, if the width of the bottom is increased and the side plate portions are extended to the tip at a constant angle, the needle tip protector will become larger. Therefore, in this aspect, in a needle tip protector in a standalone state not attached to a puncture needle, the relative inclination angle of the base end portions of the pair of side plate portions is smaller than the relative inclination angle of the tip portions of the pair of side plate portions. This prevents the needle tip protector from becoming too large and from becoming easier to assemble onto the outer needle hub when attached to the puncture needle.

[0030] A ninth aspect is a needle tip protector that is attached to a puncture needle and prevents exposure of the needle tip by moving toward the tip end where the needle tip is located, and includes a pair of side plate portions that extend along the puncture needle on both sides of the puncture needle, and a bottom portion that connects the base ends of the pair of side plate portions to each other, and when attached to the puncture needle, the puncture needle is inserted through a needle insertion hole that penetrates the bottom portion and is inserted between the pair of side plate portions, causing the pair of side plate portions to elastically deform toward each other so as to move away from each other, and the pair of side plate portions each have a side cover piece that protrudes inward in the opposing direction at one of the widthwise edge portions that are opposite to each other in the plate width direction, and the connection width dimension of the connection portion between the widthwise edge portion of the side plate and the side cover piece is 70% or less of the maximum width dimension of the side cover piece.

[0031] In the needle tip protector constructed according to this aspect, the reinforcing effect of the side cover pieces on the side plate portions is suppressed by limiting the connection width of the connection between the side plate portions and the side cover pieces, making it easier to tolerate bending deformation of the side plate portions. Therefore, for example, when the needle tip protector moves toward the tip of the puncture needle as the puncture needle is withdrawn, the resistance caused by the sliding contact between the needle tip cover portion provided on the distal end of the side plate portion and the puncture needle is reduced, allowing the puncture needle to be withdrawn with less force. Furthermore, the increased maximum width of the side cover pieces more effectively prevents lateral exposure of the puncture needle. In particular, even if the position of the puncture needle relative to the needle tip protector varies in the needle axial direction when in the needle tip protected state, the sides of the puncture needle are stably covered by the side cover pieces, preventing lateral exposure of the puncture needle by the side cover pieces.

[0032] The tenth aspect is a needle tip protector that is attached to a puncture needle and moves toward the tip where the needle tip is located to prevent the needle tip from being exposed. The needle tip protector has a plate-shaped bottom portion with a needle insertion hole through which the puncture needle is inserted, a needle guide surface with an inclined angle is formed on the opening periphery of the needle insertion hole, and a pair of elastic side plate portions are provided from the bottom toward the tip.

[0033] In the needle tip protector constructed according to this aspect, the needle guide surface is provided on the periphery of the opening of the needle insertion hole, so that even if the puncture needle is slightly misaligned radially with respect to the needle insertion hole when it is inserted into the needle insertion hole, the needle guide surface guides the puncture needle toward the needle insertion hole, allowing the puncture needle to be inserted into the needle insertion hole. In this way, the guiding action of the needle guide surface provided on the periphery of the opening of the needle insertion hole reduces the required accuracy in aligning the puncture needle with the needle insertion hole, making it easier to insert the puncture needle into the needle insertion hole. The pair of side plate portions may extend along the puncture needle on both sides of the puncture needle, or may extend toward the tip end so as to intersect each other.

[0034] In an eleventh aspect, in the needle tip protector described in the tenth aspect, the needle guide surface is formed on one opening periphery of the needle insertion hole, and a cylindrical reinforcing tube portion is protrudingly formed on the other opening periphery of the needle insertion hole.

[0035] With a needle tip protector constructed according to this aspect, the needle guide surface formed on one edge of the needle insertion hole facilitates insertion of the puncture needle into the needle insertion hole. Furthermore, although providing a slope on the edge of the opening may reduce the rigidity of the bottom, the reinforcing tube portion formed on the other edge of the needle insertion hole reinforces the bottom of the needle tip protector.

[0036] Furthermore, since the needle guide surface and the reinforcing tube portion are provided on the peripheral edge of each of the needle insertion holes, the needle guide surface and the reinforcing tube portion can be formed in a single process, for example, by performing burring or press processing on the peripheral edge of the needle insertion hole.

[0037] A twelfth aspect is a needle tip protector that is attached to a puncture needle and moves toward the tip where the needle tip is located to prevent the needle tip from being exposed, and includes a pair of side plate portions that extend along the puncture needle on both sides of the puncture needle, and a bottom portion that connects the base ends of the pair of side plate portions to each other.When attached to the puncture needle, the puncture needle is inserted through a needle insertion hole that passes through the bottom portion, and the puncture needle is inserted between the pair of side plate portions, so that the pair of side plate portions elastically deform toward each other, and when attached to the puncture needle and before needle tip protection, the relative inclination angle at the base end portions of the pair of side plate portions is greater than the relative inclination angle at the tip end portions of the pair of side plate portions.

[0038] According to the needle tip protector having the structure according to this aspect, it is possible to ensure the inclination angle on the tip side of the needle tip protector, while realizing miniaturization on the base end side of the needle tip protector.

[0039] A thirteenth aspect is a needle tip protector that is attached to a puncture needle and prevents exposure of the needle tip by moving toward the tip end where the needle tip is located, and includes a pair of side plate portions that extend along the puncture needle on both sides of the puncture needle, and a bottom portion that connects the base ends of the pair of side plate portions to each other, and when attached to the puncture needle, the puncture needle is inserted through a needle insertion hole that penetrates the bottom portion and is inserted between the pair of side plate portions, causing the pair of side plate portions to elastically deform toward each other so as to move away from each other, and at least one of the pair of side plate portions is formed with a side cover piece that protrudes inward in the opposing direction from the widthwise edge portion of the pair of side plate portions, and the connection width dimension of the connection portion between the widthwise edge portion of the side plate portion and the side cover piece is 70% or less of the maximum width dimension of the side cover piece.

[0040] In the needle tip protector constructed according to this aspect, the reinforcing effect of the side cover pieces on the side plate portions is suppressed by limiting the connection width of the connection between the side plate portions and the side cover pieces, making it easier to tolerate bending deformation of the side plate portions. Therefore, for example, when the needle tip protector moves toward the tip of the puncture needle as the puncture needle is withdrawn, the resistance caused by the sliding contact between the needle tip cover portion provided on the distal end of the side plate portion and the puncture needle is reduced, allowing the puncture needle to be withdrawn with less force. Furthermore, the increased maximum width of the side cover pieces more effectively prevents lateral exposure of the puncture needle. In particular, even if the position of the puncture needle relative to the needle tip protector varies in the needle axial direction when in the needle tip protected state, the sides of the puncture needle are stably covered by the side cover pieces, preventing lateral exposure of the puncture needle by the side cover pieces.

[0041] According to the present invention, it is possible to solve at least one of the problems associated with conventional needle tip protectors, such as reducing contact pressure with the puncture needle or outer needle hub, preventing interlocking when in a standalone state, facilitating attachment to the puncture needle, reducing the size of the tip portion when attached to the puncture needle, and avoiding interference with the inner needle hub or the like at the base end.

[0042] 3 is a perspective view showing an indwelling needle assembly equipped with a needle tip protector according to a first embodiment of the present invention; FIG. 1 is a longitudinal cross-sectional view of the indwelling needle assembly shown in FIG. 1, corresponding to the II-II cross-section of FIG. 3; FIG. 2 is a cross-sectional view of FIG. 2, showing an enlarged view of the IV-IV cross-section of FIG. 3; FIG. 1 is a perspective view of the needle tip protector constituting the indwelling needle assembly shown in FIG. 1; FIG. 5 is a perspective view of the needle tip protector shown in FIG. 5 from a different angle; 5A, 5B, 5C, 5D, 5E, 5F, 5G, 5G, 5H, 5H, 5I ...

[0043] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0044] 1 to 4 show an indwelling needle assembly 12 equipped with a needle tip protector 10 according to a first embodiment of the present invention. The indwelling needle assembly 12 is configured by combining an outer needle unit 14 and an inner needle unit 16. In the following description, the front-to-rear direction generally refers to the left-to-right direction in FIG. 2, which is the needle axial direction, the up-down direction generally refers to the up-down direction in FIG. 3, and the left-to-right direction generally refers to the up-down direction in FIG. 2. Furthermore, in the following description, the left side in FIG. 2, which is the side of the needle tip 38 described below, generally refers to the distal end, and the right side in FIG. 2 generally refers to the proximal end.

[0045] The outer needle unit 14 has a structure in which an outer needle hub 20 is fixed to the proximal end portion of an outer needle 18. The outer needle 18 is a tubular member made of synthetic resin or the like. The outer diameter of the distal end portion of the outer needle 18 decreases toward the distal end. The proximal end portion of the outer needle 18 is inserted into the distal end portion of the cylindrical outer needle hub 20, and is fixed to the outer needle hub 20 by a crimping pin 22 that is fitted into the proximal end portion of the outer needle 18 and the distal end portion of the outer needle hub 20.

[0046] The outer needle hub 20 is formed, for example, from a hard synthetic resin. The outer needle hub 20 is a member having a generally cylindrical shape overall. A luer taper that increases in diameter toward the base end is set on the inner peripheral surface of the outer needle hub 20. An external circuit such as a syringe or an infusion line can be connected to the inner cavity of the outer needle hub 20 by fitting a syringe tip or connector (not shown) into the inner cavity of the outer needle hub 20. A threaded portion 24 that protrudes outward is formed on the base end of the outer needle hub 20. The threaded portion 24 is threadedly engaged with a locking portion (not shown) provided on the external circuit, thereby preventing the external circuit from unintentionally coming off the outer needle hub 20.

[0047] The inner cavity of the outer needle hub 20 includes a housing portion 26. The housing portion 26 is provided in the axially middle portion of the outer needle hub 20. The housing portion 26 is provided by expanding the diameter of the inner cavity of the outer needle hub 20 in a concave manner on both the up-down direction and the down-down direction. As shown in FIG. 4 , the inner circumferential surface of the housing portion 26 has an elliptical cross-sectional shape, with the vertical diameter dimension being larger than the horizontal diameter dimension. The inner circumferential surfaces on both the upper and lower sides of the housing portion 26 are concave and open toward the inside in the vertical direction in the longitudinal cross section shown in FIG. 3 , and are composed of a distal tapered inner circumferential surface 28, a straight inner circumferential surface 30, and a proximal tapered inner circumferential surface 32. Note that the inner circumferential surface of the housing portion 26 is not limited to an elliptical cross-sectional shape, and may be formed by expanding the diameter in a concave manner around the entire circumference.

[0048] The distal tapered inner peripheral surface 28 is inclined to widen outward in the up-down direction toward the proximal end, with the angle of inclination relative to the front-to-rear direction decreasing from the distal end to the proximal end. The straight inner peripheral surface 30 extends linearly in the front-to-rear direction with a substantially constant diameter. The proximal tapered inner peripheral surface 32 is inclined to narrow inward toward the proximal end, with the angle of inclination relative to the front-to-rear direction increasing from the distal end to the proximal end. Therefore, the interior dimension of the storage section 26 in the up-down direction gradually increases from the distal end, reaches a maximum over a predetermined length in the front-to-rear intermediate portion, and gradually decreases toward the proximal end, resulting in an overall concave shape in the longitudinal cross section of Figure 3.

[0049] The inner needle unit 16 has a structure in which an inner needle hub 36 is attached to the proximal end portion of an inner needle 34 serving as a puncture needle. The inner needle 34 is a hollow needle made of a medical metal such as stainless steel, and is provided with a sharp needle tip 38 at its distal end. The needle tip 38 is formed by the distal end portion of the inner needle 34 having a blade surface 40 that widens and inclines relative to the needle axis. A locking portion 42 with a partially enlarged diameter is provided near the distal end of the inner needle 34 (see FIG. 17 ). The proximal end portion of the inner needle 34 is inserted into the distal end portion of the cylindrical inner needle hub 36, and the inner needle 34 and inner needle hub 36 are fixed by means of adhesion or the like.

[0050] The inner needle hub 36 is a substantially cylindrical member made of hard synthetic resin. A cylindrical connecting portion 44 that can be fitted into the proximal end opening of the outer needle hub 20 is provided at the distal end of the inner needle hub 36. A filter cap 46 is fitted into the proximal end opening of the inner needle hub 36.

[0051] The outer needle unit 14 and the inner needle unit 16 are combined with each other in a state in which the connecting portion 44 of the inner needle hub 36 is fitted into the proximal opening portion of the outer needle hub 20 and the inner needle 34 is inserted through the outer needle 18 and the outer needle hub 20, thereby forming the indwelling needle assembly 12. When a tensile force directed towards the proximal end of the outer needle unit 14 acts on the inner needle unit 16, the fitting of the connecting portion 44 with the outer needle hub 20 is released, and the outer needle unit 14 and the inner needle unit 16 can be separated from each other.

[0052] A needle tip protector 10 is attached to the inner needle 34. The needle tip protector 10 is attached in an externally fitted state to the inner needle 34 and moves toward the distal end of the inner needle 34 when the inner needle 34 is withdrawn, as described below, to prevent the needle tip 38 from being exposed. The needle tip protector 10 is formed of a medical metal such as stainless steel. As shown in FIGS. 5 to 16 , the needle tip protector 10 has a structure in which a first side plate portion 50 and a second side plate portion 52 extend from both end edges of a bottom portion 48 located on the base side of the inner needle 34 (the side opposite the needle tip 38) toward the needle tip 38. In this embodiment, the various components constituting the needle tip protector 10, described below, are integrally formed. Specifically, the various components constituting the needle tip protector 10 are formed by bending various portions of a single metal member.

[0053] As shown in Figures 5 and 6, the bottom portion 48 is a generally rectangular flat plate. A first side plate portion 50 and a second side plate portion 52 are integrally formed on a pair of opposing sides of the bottom portion 48 and extend outward toward one end of the bottom portion 48 in the thickness direction. In other words, the bottom portion 48 integrally connects the base ends of the first side plate portion 50 and the second side plate portion 52. In this embodiment, the first side plate portion 50 and the second side plate portion 52 are arranged facing each other at a distance and do not extend in an intersecting manner.

[0054] A needle insertion hole 54 is formed in the bottom portion 48, penetrating in the plate thickness direction. The needle insertion hole 54 is a circular hole large enough to allow the inner needle 34 to be inserted therethrough but large enough so that the locking portion 42 of the inner needle 34 cannot pass through. The cross-sectional shape of the needle insertion hole 54 is not limited as long as it allows the inner needle 34 to be inserted therethrough. As shown in FIGS. 13 to 15 , a needle guide surface 56 having an inclination angle is provided on the peripheral edge of the opening on the tip side of the needle insertion hole 54 in the bottom portion 48. The needle guide surface 56 is a curved surface with an arc-shaped cross section that widens so that the angle of inclination relative to the needle axial direction increases toward the tip side. The radius of curvature of the needle guide surface 56 with an arc-shaped cross section is preferably within a range of 3% to 200% of the radius of the needle insertion hole 54, and more preferably within a range of 5% to 100%. A reinforcing tube portion 58 is provided on the opening periphery of the bottom portion 48 on the base end side of the needle insertion hole 54. As shown in Figure 6, the reinforcing tube portion 58 has a generally cylindrical shape provided along the opening periphery of the needle insertion hole 54 and protrudes from the bottom portion 48 toward the base end. The protrusion dimension of the reinforcing tube portion 58 from the bottom portion 48 is preferably within the range of 3% to 200% of the diameter of the needle insertion hole 54, and more preferably within the range of 5% to 100%. Note that the needle guide surface 56 is not limited to a curved surface whose inclination angle varies depending on the position, and may be, for example, a tapered surface extending at a constant inclination angle.

[0055] The first side plate 50 has a strip-like shape extending in the front-to-rear direction. The base end of the first side plate 50, connected to the bottom 48, forms a first wide portion 60 having a width dimension approximately the same as that of the bottom 48. The first side plate 50 has a first narrow portion 62, located distally of the first wide portion 60 and having a width dimension smaller than the maximum width dimension of the needle tip cover portion. The first narrow portion 62 is a portion excluding the connection portion between the first lateral cover piece 86 and the first protruding piece 90 (described below), and is a low-rigidity portion that can be easily bent. The first narrow portion 62 does not have a rib or the like extending in the longitudinal direction (approximately the front-to-rear direction), and is preferably formed with a substantially uniform thickness overall, although this is not limited thereto. The first narrow portion 62 is formed so that its left and right ends are located closer to the left and right center than the left and right ends of the bottom 48 (first wide portion 60), thereby being located in the left-right intermediate portion of the first side plate 50 (first wide portion 60). The left and right ends of the first narrow portion 62 may be located closer to the left and right center from the left and right ends of the bottom 48 by the same left-right dimension. However, it is desirable that the central axis of the first narrow portion 62 be offset from the left-right center of the bottom 48, for purposes such as facilitating the formation of the first side cover piece 86 at an appropriate position. For example, the left-right distance between the left end (or right end) of the first narrow portion 62 and the left end (or right end) of the bottom 48 may be 1.5 times or more, and more preferably 2 times or more, the left-right distance between the right end (or left end) of the first narrow portion 62 and the right end (or left end) of the bottom 48.

[0056] The first side plate portion 50 has a first intermediate connecting portion 64 midway along the lengthwise direction, with a first distal portion 66 located distally of the first intermediate connecting portion 64 and a first proximal portion 68 located proximal to the first intermediate connecting portion 64. When the needle tip protector 10 is in a standalone state, the angle of inclination of the first distal portion 66 relative to the needle axis direction is greater than the angle of inclination of the first proximal portion 68. In this embodiment, when the needle tip protector 10 is in a standalone state, the first proximal portion 68 is substantially parallel to the needle axis direction. Furthermore, when the needle tip protector 10 is in a standalone state, the first distal portion 66 is inclined toward the second side plate portion 52 as it extends distally. The first intermediate connecting portion 64 is preferably located within a range of one-quarter to three-quarters of the length of the first side plate portion 50, and in this embodiment, it is located approximately in the center. Furthermore, the first intermediate connecting portion 64 may be, for example, a curved portion formed by bending a plate, or may be a tapered surface having an inclination angle that is larger than that of the first base end portion 68 and smaller than that of the first tip end portion 66. Furthermore, the first wide portion 60 provided at the base end of the first side plate portion 50 of this embodiment is not essential.

[0057] The length dimension L1 of the first narrow portion 62 is preferably sufficiently longer than the length dimension La of the first side plate portion 50. That is, the length dimension L1 of the first narrow portion 62 is preferably within a range of 50% to 100% of the length dimension La of the first side plate portion 50, and more preferably within a range of 60% to 95%. The length dimension L1 of the first narrow portion 62 is preferably 30% or more, and more preferably 50% or more, of the overall length dimension L0 of the first side plate portion 50 and the first needle tip cover portion 70 combined. As shown in FIG. 7 , the length dimension L1 of the first narrow portion 62 is the sum of the length dimension L1a on the distal side of the first connecting portion 88 (described later) and the length dimension L1b on the proximal side.

[0058] The first narrow width portion 62 is desirably narrower in the left-right direction than the first needle tip cover portion 70, which will be described later. Preferably, the width dimension w1 of the first narrow width portion 62 is within the range of 15% to 70% of the maximum width dimension W1 of the first needle tip cover portion 70, and more preferably within the range of 25% to 50%. This reduces the bending deformation rigidity of the first side plate portion 50 in the plate thickness direction. Note that W1 is the width dimension including the pair of first side cover pieces 84, 84, as shown in FIG. 7 .

[0059] A first needle tip cover 70 is provided on the tip side of the first side plate 50. The first needle tip cover 70 includes a first stepped portion 74 that protrudes from the tip of the first side plate 50 toward the opposite side from the second side plate 52, and a first needle tip protection portion 76 that protrudes from the protruding tip of the first stepped portion 74 toward the tip side of the second side plate 52. The first needle tip protection portion 76 protrudes from the first side plate 50 toward the tip side and also toward the second side plate 52. The first needle tip protection portion 76 includes a first tip protection piece 78 that is provided contiguous with the first stepped portion 74, and a first return piece 80 that protrudes from the tip of the first tip protection piece 78 toward the second side plate 52. The first tip protection piece 78 has a generally rectangular flat plate shape that extends obliquely toward the tip while slanting toward the second side plate portion 52. In this embodiment, the first return piece 80, which is continuous with the tip of the first tip protection piece 78, forms an obtuse angle greater than 90° with the first tip protection piece 78. The length dimension L2 of the first needle tip cover portion 70 is preferably within a range of 50% to 150% of the maximum width dimension W1 of the first needle tip cover portion 70, and more preferably within a range of 70% to 130%. Note that L2 is the length dimension of the first needle tip cover portion 70 in a direction parallel to the first tip protection piece 78, as shown in FIG. 15 .

[0060] A first needle tip restraining portion 82 is provided at the protruding tip of the first return piece 80. The first needle tip restraining portion 82 is in the shape of a generally rectangular plate. The first needle tip restraining portion 82 protrudes from the first return piece 80 toward the base end. In this embodiment, the first needle tip restraining portion 82 extends generally parallel to the first tip protection piece 78. The first needle tip restraining portion 82 is formed by bending, and is provided integrally and continuously with the first return piece 80.

[0061] A pair of first side cover pieces 84, 84 are provided on both the left and right sides of the tip portion of the first tip protection piece 78. The first side cover piece 84 is plate-shaped and extends approximately perpendicular to the left-right direction. The first side cover piece 84 protrudes from the first tip protection piece 78 toward the second side plate portion 52. The first side cover piece 84 is provided with a length that reaches the first needle tip restraining portion 82, making it difficult for the needle tip 38 to be exposed to the side in the needle tip protection state described below.

[0062] A first side cover piece 86 is provided on the first side plate 50. As shown in FIGS. 15 and 16 , the first side cover piece 86 protrudes vertically inward (downward) from one left-right edge of the first side plate 50 toward the second side plate 52. A first connecting portion 88, which is a connecting portion with the first side cover piece 86, is provided on one left-right edge of the first side plate 50. The first side cover piece 86 is located midway along the length of the first side plate 50. The first side cover piece 86 is provided on the first tip portion 66, which is closer to the tip than the first intermediate connecting portion 64. The first side cover piece 86 has a substantially constant vertical dimension at its base end portion near the bottom 48, and gradually decreases in vertical dimension at its tip portion near the first needle tip cover portion 70.

[0063] The connection width dimension w2 of the first connection portion 88 in the front-to-rear direction is smaller than the maximum width dimension W2 of the first side cover piece 86 in the same direction. The connection width dimension w2 of the first connection portion 88 is preferably within a range of 20% to 80% of the maximum width dimension W2 of the first side cover piece 86 in the same direction, and more preferably within a range of 30% to 70%. Furthermore, the connection width dimension w2 of the first connection portion 88 is preferably within a range of 5% to 30% of the length dimension La of the first side plate portion 50, and more preferably within a range of 10% to 20%. This allows the first side cover piece 86 to be stably supported by the first side plate portion 50, while ensuring a sufficient length of the first narrow portion 62 located outside the first connection portion 88, thereby suppressing deformation rigidity of the first side plate portion 50. As shown in FIG. 15, w2 and W2 are dimensions in a direction parallel to the first tip portion 66 that is inclined relative to the front-rear direction when the needle tip protector 10 is in a standalone state.

[0064] A first protruding piece 90 is provided on the first side plate 50. As shown in FIG. 16 , the first protruding piece 90 protrudes vertically inward (downward) from the other left-right edge of the first side plate 50 toward the second side plate 52. The first protruding piece 90 is located midway along the length of the first side plate 50, at the first tip portion 66, which is closer to the tip than the first intermediate connection portion 64. The first protruding piece 90 is provided on the edge of the first side plate 50 opposite the first lateral cover piece 86 in the left-right direction. The first protruding piece 90 is arranged opposite the first lateral cover piece 86 in the left-right direction. In this embodiment, the first lateral cover piece 86 and the first protruding piece 90 extend substantially parallel to each other. As shown in FIG. 13 , the first protruding piece 90 has a longer length than the first lateral cover piece 86. The first protruding piece 90 extends outward in the front-to-rear length direction relative to the first side cover piece 86. Like the first side cover piece 86, the first protruding piece 90 has a substantially constant vertical dimension at its base end portion near the bottom 48, and the vertical dimension at its tip portion near the first needle tip cover part 70 decreases toward the tip. As shown in FIG. 13 , a first restricting piece 92 is integrally formed at the end (front end) of the first protruding piece 90 on the first needle tip cover part 70 side, protruding inward in the left-to-right direction and restricting lateral displacement of the inner needle 34. The connection width dimension of the connection portion between the first side plate part 50 and the first protruding piece 90 is substantially the same as the connection width dimension w2 of the first connection portion 88, which is the connection portion between the first side plate part 50 and the first side cover piece 86. The connection width dimension of the connection portion between the first side plate portion 50 and the first protruding piece 90 is preferably 70% or less of the length dimension of the first protruding piece 90 in a direction parallel to the connection portion, and particularly preferably 50% or less.

[0065] The second side plate 52 has a strip-like shape extending in the front-to-rear direction. The base end of the second side plate 52, connected to the bottom 48, forms a second wide portion 94 with a lateral width dimension substantially equal to that of the bottom 48. The second side plate 52 has a second narrow portion 96 with a lateral width dimension smaller than the maximum width dimension of the needle tip cover portion, located distally of the second wide portion 94, excluding the connection between the second lateral cover piece 120 and the second protruding piece 124 (described later). The second narrow portion 96 is a low-rigidity portion that can be easily deformed. The second narrow portion 96 preferably does not have a longitudinally extending rib or the like that would increase deformation rigidity, and has a substantially constant thickness overall, although this is not limited thereto. The second narrow portion 96 is formed so that its lateral ends are located closer to the lateral center than the lateral ends of the bottom 48 (second wide portion 94), thereby being positioned in the lateral middle of the second side plate 52 (second wide portion 94). The left and right ends of the second narrow portion 96 may be located toward the center in the left-right direction from the left and right ends of the bottom 48 (second wide portion 94) by the same left-right dimension; however, for purposes such as facilitating the formation of the second side cover piece 120 at an appropriate position, it is desirable that the central axis of the second narrow portion 96 be offset from the center in the left-right direction of the bottom 48. For example, the left-right distance between the left end (or right end) of the second narrow portion 96 and the left end (or right end) of the bottom 48 may be 1.5 times or more, and more preferably 2 times or more, the left-right distance between the right end (or left end) of the second narrow portion 96 and the right end (or left end) of the bottom 48.

[0066] The second side plate portion 52 has a second intermediate connecting portion 98 midway in the longitudinal direction, with the portion distal to the second intermediate connecting portion 98 being a second distal portion 100 and the portion proximal to the second intermediate connecting portion 98 being a second proximal portion 102. When the needle tip protector 10 is in a standalone state, the inclination angle of the second distal portion 100 with respect to the needle axis direction is larger than the inclination angle of the second proximal portion 102. In this embodiment, when the needle tip protector 10 is in a standalone state, the second proximal portion 102 is approximately parallel to the needle axis direction. Furthermore, when the needle tip protector 10 is in a standalone state, the second distal portion 100 is inclined toward the first side plate portion 50 as it approaches the distal end. The second intermediate connecting portion 98 is preferably located ¼ to ¾ of the length of the second side plate portion 52 away from the base end, and in this embodiment, is located approximately in the center in the longitudinal direction of the second side plate portion 52. The second intermediate connecting portion 98 may be, for example, a curved portion formed by bending a plate, or may be a tapered surface having an inclination angle that is larger than that of the second base end portion 102 and smaller than that of the second tip end portion 100.

[0067] The length dimension L3 of the second narrow portion 96 is preferably sufficiently longer than the length dimension Lb of the second side plate portion 52. That is, the length dimension L3 of the second narrow portion 96 is preferably within a range of 50% to 100% of the length dimension Lb of the second side plate portion 52, and more preferably within a range of 60% to 95%. The length dimension L3 of the second narrow portion 96 is preferably 30% or more, and more preferably 50% or more, of the overall length dimension L0' of the second side plate portion 52 and the second needle tip cover portion 104 (described below). As shown in FIG. 8 , the length dimension L3 of the second narrow portion 96 is the sum of the length dimension L3a on the distal side of the second connecting portion 122 (described below) and the length dimension L3b on the proximal side. Furthermore, as shown in Figures 7 and 8, L0, L0', L1, and L3 are length dimensions in the front-to-back direction, and even if, for example, the first and second side plate portions 50 and 52 are inclined partially or entirely with respect to the front-to-back direction, the above length dimensions are understood to be lengths in the front-to-back direction (front-to-back lengths in up-down projection).

[0068] The second narrow width portion 96 is desirably narrower in the left-right direction than the second probe tip cover portion 104, which will be described later. Preferably, the width dimension w3 of the second narrow width portion 96 is within the range of 15% to 70% of the maximum width dimension W3 of the second probe tip cover portion 104, and more preferably within the range of 25% to 50%. This reduces the bending deformation rigidity in the plate thickness direction of the second side plate portion 52. Note that W3 is the width dimension including the pair of second side cover pieces 118, 118, as shown in FIG. 8.

[0069] A second needle tip cover part 104 is provided on the tip side of the second side plate part 52. The second needle tip cover part 104 includes a second stepped part 108 that protrudes from the tip of the second side plate part 52 toward the opposite side from the first side plate part 50, and a second needle tip protection part 110 that protrudes from the protruding tip of the second stepped part 108 toward the tip side of the first side plate part 50. The second stepped part 108, which is the base end part of the second needle tip cover part 104, is desirably disposed at a different position in the front-to-rear direction from the first stepped part 74, which is the base end part of the first needle tip cover part 70. In this embodiment, the first stepped part 74 is located closer to the base end than the second stepped part 108. In this embodiment, the length of extension forward from the first stepped portion 74 of the first needle tip protection part 76 is set to be approximately the same as the length of extension forward from the second stepped portion 108 of the second needle tip protection part 110. As a result, due to the misalignment in the front-to-rear direction between the first stepped portion 74 and the second stepped portion 108, the tip portion (front end) of the first needle tip protection part 76 is located closer to the base end (rear side) than the tip portion of the second needle tip protection part 110.

[0070] The second needle tip protection portion 110 protrudes from the second side plate portion 52 toward the tip side and also protrudes toward the first side plate portion 50. The second needle tip protection portion 110 is configured to include a second tip protection piece 112 that is provided continuous with the second step-shaped portion 108, and a second return piece 114 that protrudes from the tip of the second tip protection piece 112 toward the first side plate portion 50. The second tip protection piece 112 has a generally rectangular flat plate shape that extends obliquely toward the tip side while inclining toward the first side plate portion 50. In this embodiment, the second return piece 114 that is continuous with the tip side of the second tip protection piece 112 forms an obtuse angle with the second tip protection piece 112 that is greater than 90°. The length dimension L4 of the second needle tip cover part 104 is preferably within a range of 50% to 150% of the maximum width dimension W3 of the second needle tip cover part 104, and more preferably within a range of 70% to 130%. Note that L4 is the length dimension of the second needle tip cover part 104 in a direction parallel to the second tip protection piece 112, as shown in Figure 15.

[0071] A second needle tip restraining portion 116 is provided at the protruding tip of the second return piece 114. The second needle tip restraining portion 116 is in the shape of a substantially rectangular plate. The second needle tip restraining portion 116 protrudes from the second return piece 114 toward the base end. In this embodiment, the second needle tip restraining portion 116 extends substantially perpendicular to the second return piece 114. The second needle tip restraining portion 116 is formed by bending, and is provided integrally and continuously with the second return piece 114.

[0072] A pair of second side cover pieces 118, 118 are provided on both left and right sides of the tip portion of the second tip protection piece 112. The second side cover pieces 118 are plate-shaped and extend substantially perpendicular to the left and right direction. The second side cover pieces 118 protrude from the second tip protection piece 112 toward the first side plate portion 50. The second side cover pieces 118 are provided with a length that reaches the second needle tip prevention portion 116.

[0073] A second side cover piece 120 is provided on the second side plate portion 52. As shown in FIGS. 14 and 16 , the second side cover piece 120 protrudes inward (upward) from the other left-right edge of the second side plate portion 52 toward the first side plate portion 50. A second connecting portion 122, which is a connecting portion with the second side cover piece 120, is provided on the other left-right edge of the second side plate portion 52. The second side cover piece 120 is located midway along the length of the second side plate portion 52. The second side cover piece 120 is provided on the second tip portion 100, which is closer to the tip than the second intermediate connecting portion 98. The second side cover piece 120 has a substantially constant vertical dimension at its base end portion near the bottom portion 48, and the vertical dimension gradually decreases toward the tip at its tip portion near the second needle tip cover portion 104.

[0074] The connection width dimension w4 of the second connection portion 122 in the front-to-rear direction is smaller than the maximum width dimension W4 of the second side cover piece 120 in the same direction. The connection width dimension w4 of the second connection portion 122 is preferably within a range of 20% to 80% of the maximum width dimension W4 of the second side cover piece 120 in the same direction, and more preferably within a range of 30% to 70%. Furthermore, the connection width dimension w4 of the second connection portion 122 is preferably within a range of 5% to 30% of the length dimension Lb of the second side plate portion 52, and more preferably within a range of 10% to 20%. By setting the connection width dimension w4 of the second connection portion 122 in this manner, the second side cover piece 120 is stably supported by the second side plate portion 52, and the length of the second narrow portion 96, which is located outside the second connection portion 122, is sufficiently secured, thereby suppressing the deformation rigidity of the second side plate portion 52. As shown in FIG. 14, w4 and W4 are dimensions in a direction parallel to the second tip portion 100 that is inclined relative to the front-rear direction when the needle tip protector 10 is in a standalone state.

[0075] A second protruding piece 124 is provided on the second side plate 52. As shown in FIGS. 15 and 16 , the second protruding piece 124 extends from one of the left and right edges of the second side plate 52 toward the first side plate 50. The second protruding piece 124 is located midway along the length of the second side plate 52, in a second tip portion 100 that is closer to the tip than the second intermediate connecting portion 98. The second protruding piece 124 is provided on an edge of the second side plate 52 opposite the second lateral cover piece 120 in the left and right direction. The second protruding piece 124 is arranged opposite the second lateral cover piece 120 in the left and right direction. In this embodiment, the second lateral cover piece 120 and the second protruding piece 124 extend substantially parallel to each other. As shown in FIG. 13 , the second protruding piece 124 has a longer length than the second lateral cover piece 120. The second protruding piece 124 extends outward in the longitudinal direction relative to the second side cover piece 120. Like the second side cover piece 120, the second protruding piece 124 has a substantially constant vertical dimension at its base end portion near the bottom 48, and the vertical dimension at its tip portion near the second needle tip cover part 104 decreases toward the tip. As shown in FIG. 13 , a second restricting piece 126 is integrally formed at the end (front end) of the second protruding piece 124 on the second needle tip cover part 104 side, protruding inward in the left-right direction and restricting lateral displacement of the inner needle 34. The connection width dimension of the connection portion between the second side plate part 52 and the second protruding piece 124 is substantially the same as the connection width dimension w4 of the second connection portion 122, which is the connection portion between the second side plate part 52 and the second side cover piece 120. The connection width dimension of the connection portion between the second side plate portion 52 and the second protruding piece 124 is preferably 70% or less of the length dimension of the second protruding piece 124 in a direction parallel to the connection portion, and particularly preferably 50% or less.

[0076] The first side cover piece 86 and the second protruding piece 124 are provided on the left-right edge portions of the first side plate portion 50 and the second side plate portion 52, and overlap each other in the left-right direction when attached to the inner needle 34 before needle tip protection. As shown in FIG. 16 , the first side cover piece 86 is located on the inside of the second protruding piece 124 in the left-right direction. The first side cover piece 86 has a protruding height that does not reach the second side plate portion 52. The second protruding piece 124 has a protruding height that does not reach the first side plate portion 50. The first side cover piece 86 and the second protruding piece 124 partially overlap each other. Furthermore, as shown in FIG. 15 , the second protruding piece 124 extends outward on both longitudinal sides of the first side cover piece 86.

[0077] As shown in FIG. 16 , the second side cover piece 120 and the first protruding piece 90 are provided on the same left-right edge of the first side plate portion 50 and the second side plate portion 52, and overlap each other left-right when attached to the inner needle 34 before needle tip protection. The second side cover piece 120 is located on the inside of the first protruding piece 90 in the left-right direction. The second side cover piece 120 has a protruding height that does not reach the first side plate portion 50. The first protruding piece 90 has a protruding height that does not reach the second side plate portion 52. The second side cover piece 120 and the first protruding piece 90 partially overlap each other. Furthermore, as shown in FIG. 14 , the first protruding piece 90 extends outward in both the front-to-rear direction and outward from the second side cover piece 120. In this way, by increasing the length dimension in the front-to-rear direction of the first and second protruding pieces 90, 124, it becomes more difficult for the needle tip 38 to be exposed to the left and right sides in the needle tip protection state described below.

[0078] In this way, the first and second side cover pieces 86, 120 and the first and second protruding pieces 90, 124 overlap with each other, thereby preventing the inner needle 34 from being exposed to the outside between the first side cover piece 86 and the second side plate portion 52 and between the second side cover piece 120 and the first side plate portion 50. Furthermore, even if, for example, the first and second side plate portions 50, 52 are flexibly deformed in directions separating them from each other, the overlapping of the first and second side cover pieces 86, 120 and the first and second protruding pieces 90, 124 is maintained without being released, preventing the inner needle 34 from being exposed to the left and right sides.

[0079] As shown in Figure 16, the first side cover piece 86 and the second side cover piece 120 are provided on both left and right sides and face each other at a distance in the left and right direction. The first protruding piece 90 and the second protruding piece 124 are provided on both left and right sides and face each other at a distance in the left and right direction. The first protruding piece 90 and the second protruding piece 124 are located on both left and right outer sides of the first and second side cover pieces 86, 120.

[0080] 14 and 15 , the first and second side cover pieces 86, 120 and the first and second protruding pieces 90, 124 are all spaced apart in the longitudinal direction from the bottom 48 toward the tip end, and a molding space 128 that penetrates in the left-right direction between the opposing surfaces of the first and second side plate portions 50, 52 and is open on both left-right sides is formed between the first and second side cover pieces 86, 120 and the first and second protruding pieces 90, 124 and the bottom 48. In this embodiment, the first and second protruding pieces 90, 124 extend near the first and second intermediate connecting portions 64, 98, and the molding space 128 is provided closer to the base end than the first and second intermediate connecting portions 64, 98. In this embodiment, the first and second projecting pieces 90, 124 project further toward the base end than the first and second side cover pieces 86, 120, and therefore the size of the molding space 128 is limited by the first and second projecting pieces 90, 124. Therefore, exposure of the inner needle 34 to the outside through the molding space 128 is reduced, and problems such as other needle tip protectors 10 entering and becoming tangled in the molding space 128 are avoided when, for example, a large number of needle tip protectors 10 are housed and stored in a container.

[0081] The needle tip protector 10 is formed, for example, by bending a metal blank punched into a predetermined shape using a press (progressive press). During the press, the bottom portion 48 can be pressed down using the forming space 128. That is, during the press, the portion corresponding to the bottom portion 48 is clamped in the thickness direction between a support jig (not shown) that supports one side and a clamping jig (not shown) that supports the other side. The clamping jig is shaped to be insertable into the forming space 128 and is placed over the raised sides of the first and second side plate portions 50, 52 relative to the bottom portion 48. This allows the bottom portion 48 to be held in a clamped state from the start to the end of the press, facilitating the molding of the needle tip protector 10. The clamping jig also functions as a mold when bending and molding the first and second side plate portions 50, 52 relative to the bottom portion 48. The metal plate processed into the needle tip protector 10 by the progressive press is made of, for example, medical-grade stainless steel or titanium, and is preferably a plate material having a thickness of 0.05 to 0.3 mm. By using a metal plate with such a thickness range, it is possible to obtain a needle tip protector 10 that has sufficiently small sliding resistance against the inner needle 34 and deformation rigidity that can stably maintain the needle tip protection form, and damage during press processing is unlikely to be a problem. The needle tip protector 10 may have a substantially constant thickness overall, or may have thick and / or thin portions.

[0082] In the needle tip protector 10 alone, the relative inclination angle θ1 between the first base end portion 68 of the first side plate portion 50 and the second base end portion 102 of the second side plate portion 52 is smaller than the relative inclination angle θ2 between the first tip end portion 66 and the second tip end portion 100. The magnitude of the relative inclination angle θ1 between the first base end portion 68 and the second base end portion 102 is preferably within a range of −10° to 10°. In this embodiment, the first base end portion 68 and the second base end portion 102 are substantially parallel to each other, and θ1 is set to approximately 0°. Furthermore, the magnitude of the relative inclination angle θ2 between the first tip end portion 66 and the second base end portion 102 is preferably within a range of 5° to 30°. For example, the first base end portion 68 and the second base end portion 102 may each be inclined upward and downward outward toward the tip side, and the first tip end portion 66 and the second tip end portion 100 may each be inclined upward and downward inward toward the tip side.

[0083] In this way, the relative inclination angle θ1 between the first base end portion 68 and the second base end portion 102 is smaller than the relative inclination angle θ2 between the first distal end portion 66 and the second distal end portion 100, thereby improving the ease of assembly of the needle tip protector 10 to the outer needle hub 20 and reducing its size. That is, for example, when an engaging portion that protrudes on the inner circumferential surface is provided, such as on the proximal end side of the accommodation section 26 of the outer needle hub 20, in a structure in which the first and second side plate portions extend to the distal end at a constant angle without increasing the width of the bottom portion 48 (the opposing distance between the first and second side plate portions at the proximal ends), when assembling the needle tip protector to the outer needle hub 20, the first and second side plate portions bent due to the stress when the needle tip cover portion (step-shaped portion) of the needle tip protector moves over the engaging portion of the outer needle hub 20 may come into contact with the inner needle 34, which may reduce the ease of assembly of the needle tip protector to the outer needle hub 20. In particular, when the inner needle 34 is thick, interference between the inner needle 34 and the first and second side plate portions of the needle tip protector is likely to become a problem. On the other hand, if the width of the bottom portion 48 is increased and the first and second side plate portions are extended to the tip at a certain angle, the needle tip protector will become larger. Therefore, in the present embodiment, in the needle tip protector 10 in a standalone state not attached to the inner needle 34, the relative inclination angle θ1 of the first and second base end portions 68, 102 is made smaller than the relative inclination angle θ2 of the first and second tip end portions 66, 100. This prevents both a decrease in ease of assembly of the needle tip protector 10 to the outer needle hub 20 and an increase in size of the needle tip protector 10 when attached to the inner needle 34. Furthermore, when the needle tip protector 10 is in a standalone state without being attached to the inner needle 34, the distance between the opposing surfaces of the first and second side plate portions 50, 52 in their initial shape when no external force is applied can be easily set to a size that prevents the first and second needle tip cover portions 70, 104 in their initial shape when no external force is applied from entering.

[0084] The first intermediate connecting portion 64 and the second intermediate connecting portion 98 are formed by bending the respective intermediate portions of the first narrow width portion 62 and the second narrow width portion 96 when the needle tip protector 10 is formed by press working. Furthermore, when bending the first narrow width portion 62 and the second narrow width portion 96, the relative inclination angle between the first distal end portion 66 and the first proximal end portion 68 and the relative inclination angle between the second distal end portion 100 and the second proximal end portion 102 are set to appropriate angles by a mold (jig). This makes it possible to ensure the effective length of the arm while suppressing the maximum radial dimension, and to achieve an excellent needle tip 38 protection structure due to the overlap of the first and second needle tip cover portions 70, 104 when protecting the needle tip.

[0085] In the state where the needle tip protector 10 is in a standalone state, the distance D between the opposing surfaces in the vertical direction between the first side plate portion 50 and the second side plate portion 52 is set to a size that prevents the tip portion of the needle tip protector 10, which is made up of the first and second needle tip cover portions 70, 104, from entering in its initial shape that is not deformed by external forces. In this embodiment, in the state where the needle tip protector 10 is in a standalone state, the distance D between the opposing surfaces in the vertical direction between the first side plate portion 50 and the second side plate portion 52 is set to be smaller than at least one of the maximum width dimension W1 of the first needle tip cover portion 70 and the maximum width dimension W3 of the second needle tip cover portion 104. The maximum width dimension W1 of the first needle tip cover portion 70 and the maximum width dimension W3 of the second needle tip cover portion 104 are approximately the same size, and the distance D between the opposing surfaces in the vertical direction of the first side plate portion 50 and the second side plate portion 52 is smaller than both the maximum width dimension W1 of the first needle tip cover portion 70 and the maximum width dimension W3 of the second needle tip cover portion 104. As a result, for example, when multiple needle tip protectors 10 are individually stored in a box, bottle, or the like for storage or transportation, the tip portion of the needle tip protector 10, which is tapered in the vertical direction, is unlikely to get caught between the opposing surfaces in the vertical direction of the first side plate portion 50 and the second side plate portion 52 of another needle tip protector 10 (molding space 128). Therefore, multiple needle tip protectors 10 are unlikely to become entangled, and the effort required to untangle them can be reduced. In this embodiment, the distance D between the opposing surfaces of the first and second side plate portions 50, 52 is substantially constant in the opposing portion between the first base end portion 68 and the second base end portion 102, and decreases at a substantially constant rate toward the distal end in the opposing portion between the first distal end portion 66 and the second distal end portion 100. However, for example, the distance D between the opposing surfaces may vary in the opposing portion between the first base end portion 68 and the second base end portion 102, or the rate of change may not be constant in the opposing portion between the first distal end portion 66 and the second distal end portion 100. Furthermore, a widened portion larger than the maximum width dimension W1 of the first needle tip cover portion 70 and the maximum width dimension W3 of the second needle tip cover portion 104 may be formed in part of the first and second side plate portions 50, 52. Even in this case, by adjusting the length of the widening portion, it is possible to prevent the tip portion of the needle tip protector 10, which is made up of the first and second needle tip cover portions 70, 104, from entering between the opposing surfaces of the first and second side plate portions 50, 52, in the initial shape of the needle tip protector 10 without deformation due to external forces.In addition, a convex portion may be provided on the opposing inner surfaces of the first and second side plate portions 50, 52 to partially shorten the distance D between the opposing surfaces, so that the needle tip cover portions 70, 104 do not enter the gap between the first and second side plate portions 50, 52 due to contact with the convex portion.

[0086] 14 , the maximum outer dimension W5 of the first needle tip cover part 70 and the second needle tip cover part 104 in the vertical direction refers to the distance in the vertical direction between the upper end (the protruding tip of the first stepped part 74) of the first needle tip protection part 76 and the lower end (the protruding tip of the second stepped part 108) of the second needle tip protection part 110. This makes it possible to more effectively prevent the needle tip protectors 10 from becoming entangled with each other due to the tip part of one needle tip protector 10 entering the molding space 128 of another needle tip protector 10.

[0087] The needle tip protector 10 constructed as described above is attached to the inner needle 34, as shown in Figures 17 and 18. That is, the inner needle 34 is inserted through the needle insertion hole 54 formed in the bottom portion 48 of the needle tip protector 10, and is also inserted between the first needle tip cover portion 70 and the second needle tip cover portion 104. As a result, the inner needle 34 is disposed so as to penetrate between the opposing first side plate portion 50 and second side plate portion 52 of the needle tip protector 10, and the needle tip protector 10 is attached in an externally inserted state to the inner needle 34. The first side plate portion 50 and the second side plate portion 52 extend along the inner needle 34 on both sides of the inner needle 34, and do not intersect in a cross-sectional view of the first side plate portion 50 and the second side plate portion 52. 18 , the first side plate portion 50 and the second side plate portion 52 extend without intersecting with the inner needle 34, and the distal end and proximal end of the first side plate portion 50 are both located on the same side (upper side) of the inner needle 34, while the distal end and proximal end of the second side plate portion 52 are both located on the same side (lower side) of the inner needle 34. The inner needle 34 is located between the opposing first side cover piece 86 and second side cover piece 120 of the needle tip protector 10, and is surrounded around the periphery by the first and second side plate portions 50, 52, the first and second side cover pieces 86, 120, and the first and second projecting pieces 90, 124 in a part of the needle axial direction. In Figure 17, for ease of viewing, the needle tip protector 10 is positioned away from the inner needle hub 36 toward the needle tip 38, but as shown in Figures 2 and 3, the needle tip protector 10 is positioned so that the bottom 48 is in contact with or close to the tip of the inner needle hub 36.

[0088] After the needle tip protector 10 is attached to the inner needle 34 alone, for example, without the inner needle hub 36, the proximal end is fixed to the inner needle hub 36. That is, a force that separates the first and second side plate portions 50, 52 from each other in the vertical direction is applied to the needle tip protector 10, and in a state in which the first needle tip cover portion 70 and the second needle tip cover portion 104 are separated from each other in the vertical direction, the inner needle 34 alone is inserted between the first and second side plate portions 50, 52 from the distal end side of the needle tip protector 10, thereby attaching the needle tip protector 10 to the inner needle 34. Then, the inner needle hub 36 is fixed to the proximal end of the inner needle 34 with the needle tip protector 10 attached.

[0089] In the present embodiment, a needle guide surface 56 is provided on the peripheral edge of the opening on the tip side of the needle insertion hole 54 formed in the bottom 48 of the needle tip protector 10. As a result, when the inner needle 34 is inserted into the needle insertion hole 54 from the tip side of the needle tip protector 10, even if the inner needle 34 is slightly misaligned in the radial direction with respect to the needle insertion hole 54, the base end of the inner needle 34 abuts against the needle guide surface 56, and the inner needle 34 is guided into the needle insertion hole 54. Therefore, a high degree of accuracy in relative positioning of the inner needle 34 and the needle tip protector 10 in the radial direction is not required, and the work of attaching the needle tip protector 10 to the inner needle 34 is simplified.

[0090] The bottom 48 of the needle tip protector 10 is provided with a reinforcing tube portion 58 that protrudes from the peripheral edge of the opening on the proximal side of the needle insertion hole 54 toward the proximal end. The bottom 48 is formed from the same thin plate as the first and second side plate portions 50, 52, and is therefore thin and plate-like, which may cause deformation. Therefore, by providing the reinforcing tube portion 58, the deformation rigidity of the bottom 48 around the needle insertion hole 54 can be improved. For example, even if the proximal end of the inner needle 34 abuts against the needle guide surface 56, deformation of the bottom 48 is suppressed, allowing the needle guide surface 56 to effectively guide the inner needle 34. This also prevents deformation of the bottom 48 and affects the position and shape of the first and second side plate portions 50, 52. When the needle guide surface 56 is provided, the needle guide surface 56 can prevent a decrease in the deformation rigidity of the bottom 48. It is also possible to provide only the reinforcing tube portion 58 without providing the needle guide surface 56.

[0091] When the needle tip protector 10 is attached to the inner needle 34, the first and second needle tip protecting portions 76, 110 of the needle tip protector 10 are spaced apart from each other in the up-down direction, and accordingly, the first and second side plate portions 50, 52 are elastically flexed and deformed in the plate thickness direction. Then, in the attached state of the needle tip protector 10 on the inner needle 34 before needle tip protection operation, the relative inclination angle θ1' between the first base end portion 68 of the first side plate portion 50 and the second base end portion 102 of the second side plate portion 52 is larger than the relative inclination angle θ2' between the first distal end portion 66 and the second distal end portion 100. In the attached state of the needle tip protector 10 on the inner needle 34 before needle tip protection operation, the magnitude of the relative inclination angle θ1' between the first proximal end portion 68 and the second proximal end portion 102 is preferably within the range of 0° to 30°. Furthermore, in the attached state of the needle tip protector 10 before needle tip protection operation for the inner needle 34, the magnitude of the relative inclination angle θ2' between the first tip portion 66 and the second tip portion 100 is preferably within the range of -5° to 5°. In this embodiment, the first tip portion 66 and the second tip portion 100 are approximately parallel to each other, and θ2' is approximately 0°.

[0092] 18 , when the needle tip protector 10 is attached to the inner needle 34, the inner needle 34 is inserted between the first needle tip restraint portion 82 and the second needle tip restraint portion 116. The first needle tip restraint portion 82 contacts the outer peripheral surface of the inner needle 34 at the base end protruding from the first return piece 80. This reduces the contact area between the inner needle 34 and the first needle tip restraint portion 82, reducing frictional resistance when the inner needle 34 is pulled out. Furthermore, the second needle tip restraint portion 116 extends approximately parallel to the needle axis of the inner needle 34 and contacts the outer peripheral surface of the inner needle 34 over a wider axial range than the first needle tip restraint portion 82. This effectively provides a guiding effect for guiding the inner needle 34 in the needle axial direction when the inner needle 34 is pulled out, suppressing swing (tilting) of the inner needle 34 when pulled out.

[0093] 2 to 4, the needle tip protector 10 attached to the inner needle 34 is housed in the lumen of the outer needle hub 20. The tip portion of the needle tip protector 10 is tapered in the vertical direction by the first and second tip protection pieces 78, 112 having an inclined shape that approaches each other toward the tip. Therefore, when inserting the needle tip protector 10 into the outer needle hub 20, it is possible to prevent the inner circumferential surface of the outer needle hub 20 from being damaged by the needle tip protector 10 being unintentionally caught.

[0094] Furthermore, the length dimension L2 of the first needle tip cover part 70 is set to be 50% or more of the maximum width dimension W1, and when the needle tip protector 10 is attached to the inner needle 34 as shown in Figure 18, the angle α formed by the straight line A connecting the point located outermost (upper) in the opposing direction (up-down direction) of the first and second side plate parts 50, 52 of the first needle tip cover part 70 (the connection point between the first stepped part 74 and the first needle tip protection part 76) and the contact point with the inner needle 34 and the needle axis of the inner needle 34 is set to be 60 degrees or less. 18 , the angle β formed by a line B connecting a point located outermost (lower) in the opposing direction (up-down direction) of the first and second side plate portions 50, 52 on the second needle tip cover portion 104 (the connection point between the second stepped portion 108 and the second needle tip protection portion 110) and the point of contact with the inner needle 34, and the needle axis of the inner needle 34 is 60 degrees or less. This allows the lengths of the first needle tip cover portion 70 and the second needle tip cover portion 104 to be sufficiently long in the needle tip protected state, making it possible to reduce the component of force perpendicular to the axis on the inner needle 34 due to the elastic force of the needle tip protector 10 and reduce sliding resistance when the inner needle 34 is pulled out. Furthermore, when the needle tip protector 10 attached to the inner needle 34 is inserted into the inner circumference of the outer needle hub 20, etc., the displacement of the first and second needle tip cover parts 70, 104 makes it difficult for the needle tip protector 10 to be pressed strongly against the inner surface of the outer needle hub 20, and damage to the inner surface of the outer needle hub 20 due to the pressing of the needle tip protector 10 is also prevented.

[0095] Furthermore, when the first and second needle tip cover portions 70, 104 climb over the locking portion 42 of the inner needle 34, the first and second return pieces 80, 114 are pushed vertically outward by the locking portion 42, with the first and second step portions 74, 108 being restricted from vertically outward displacement by the outer needle hub 20. In the present embodiment, the first and second tip protection pieces 78, 112 extend at an angle toward the inner needle 34, and the first and second step portions 74, 108 and the first and second return pieces 80, 114 are misaligned with each other in the needle axial direction, so that relative separation displacement of the first and second return pieces 80, 114 is permitted by vertically inward displacement of the first and second step portions 74, 108 which accompanies flexural deformation of the first and second side plate portions 50, 52 (first and second narrow width portions 62, 96), which have low deformation rigidity. Therefore, the tip portions of the first and second needle tip cover parts 70, 104 are more easily allowed to move outward in the vertical direction, preventing the tip portions from being pressed strongly against the inner needle 34, and reducing the sliding resistance of the first and second needle tip cover parts 70, 104 against the inner needle 34.

[0096] Furthermore, because the first and second tip protection pieces 78, 112 of the first and second needle tip cover parts 70, 104 extend distally while inclining towards the inner needle 34, the positions of the first and second stepped parts 74, 108 differ in the needle axial direction, and the tip position of the second needle tip cover part 104 is located further distally than the base end position of the first needle tip cover part 70. As a result, in the needle tip protection state, the second needle tip cover part 104 overlaps the first needle tip cover part 70 with a larger overlap, thereby realizing more stable protection of the needle tip 38.

[0097] The first and second needle tip cover portions 70, 104 of the needle tip protector 10 are inserted into and housed in the housing portion 26 of the outer needle hub 20. The first and second stepped portions 74, 108 come into contact with the inner circumferential surface of the housing portion 26, thereby restricting movement of the needle tip protector 10 toward the base end relative to the outer needle hub 20. Because the first and second stepped portions 74, 108 of the needle tip protector 10 are both located on the straight inner circumferential surface 30 of the housing portion 26, neither one is pressed strongly against the outer needle hub 20, and the needle tip protector 10 is housed stably in the housing portion 26.

[0098] In order to suppress unnecessary rattle of the needle tip protector 10 relative to the inner needle 34, for example, the bottom 48 or the outermost square portions of the first and second needle tip cover portions 70, 104 may be arranged in close proximity to or in contact with the inner circumferential surface of the outer needle hub 20. In addition, in order to limit rotation of the needle tip protector 10 around the inner needle 34, the connecting portion 44 of the inner needle hub 36 inserted into the outer needle hub 20 may be made to partially protrude circumferentially toward the tip side (see FIG. 3 ), and this protruding portion may be made to fit outside the edge of the bottom 48 of the needle tip protector 10.

[0099] In the indwelling needle assembly 12 equipped with such a needle tip protector 10, for example, the inner needle 34 and the outer needle 18 are inserted into a patient's blood vessel, etc. After the inner needle 34 and the outer needle 18 have inserted into the blood vessel, the inner needle unit 16 is pulled toward the proximal end while the outer needle unit 14 is held in the puncture position, whereby the inner needle 34 is withdrawn from the outer needle 18 toward the proximal end.

[0100] When the inner needle 34 is pulled out from the outer needle 18 toward the proximal end, the needle tip protector 10 housed in the housing portion 26 of the outer needle hub 20 is restricted from moving toward the proximal end because the first and second stepped portions 74, 108 catch on the proximal tapered inner circumferential surface 32 of the housing portion 26. The needle tip protector 10 then moves toward the needle tip 38 while making sliding contact with the outer circumferential surface of the inner needle 34.

[0101] At this time, the connection portions between the first and second return pieces 80, 114 and the first and second needle tip restraining portions 82, 116, which come into sliding contact with the outer peripheral surface of the inner needle 34, have a curved cross section that widens toward the tip. Therefore, when the inner needle 34 is pulled out, the inner needle 34 is less likely to get caught on the needle tip protector 10 at the connection portions between the first and second return pieces 80, 114 and the first and second needle tip restraining portions 82, 116, thereby achieving smooth pulling of the inner needle 34 toward the base end and smooth relative displacement of the needle tip protector 10 toward the needle tip 38.

[0102] 18 , the first needle tip preventing portion 82 is inclined in a direction away from the inner needle 34 toward the tip protruding from the first return piece 80, thereby further reducing sliding resistance when the inner needle 34 is pulled out. Furthermore, the connection portions of the first and second return pieces 80, 114 and the first and second needle tip preventing portions 82, 116, which come into sliding contact with the outer circumferential surface of the inner needle 34, are offset from each other in the needle axial direction. Therefore, for example, when the locking portion 42 of the inner needle 34, which has a larger diameter than the other portions, passes through, the sliding contact portion of the inner needle 34 moves over the locking portion 42 in order, rather than simultaneously, thereby reducing sliding resistance when moving over the locking portion 42.

[0103] The front-to-rear length dimension L1 of the first narrow width portion 62 is within a range of 50% to 100% of the front-to-rear length dimension La of the first side plate portion 50. Furthermore, the front-to-rear length dimension L3 of the second narrow width portion 96 is within a range of 50% to 100% of the front-to-rear length dimension Lb of the second side plate portion 52. As a result, the bending deformation rigidity of the first and second narrow width portions 62, 96 is reduced.

[0104] The needle tip protector 10 of this embodiment has a significantly reduced sliding resistance compared to conventional needle tip protectors. Specifically, the needle tip protector described in Figure 30 of International Publication No. 2023 / 090462 had sliding resistance values ​​of 160 gf at 16 gauge, 84 gf at 18 gauge, and 64 gf at 24 gauge when the large-diameter portion corresponding to the locking portion 42 of the inner needle 34 passed between a pair of needle tip cover portions. However, the needle tip protector 10 of this embodiment had sliding resistance values ​​of 24 gf at 16 gauge, 16 gf at 18 gauge, and 6 gf or less at 24 gauge. Furthermore, when a commercially available product in which the side plate portion crosses the inner needle was measured, the sliding resistance value at 24 gauge was 30 gf. By reducing the sliding resistance value in this manner, it is possible to prevent the outer needle 18 from being pulled toward the proximal end together with the inner needle 34 via the needle tip protector 10 when the inner needle 34 is pulled out after puncturing a blood vessel, and it is possible to prevent the outer needle 18 from being unintentionally pulled out from within the blood vessel. The dimensions and arrangement of each part of the needle tip protector 10 can be changed as appropriate depending on the thickness (gauge) of the inner needle 34. For example, the positions of the first and second side cover pieces 86, 120 and the first and second restricting pieces 92, 126 can be changed depending on the thickness of the inner needle 34.

[0105] The sliding resistance of the needle tip protector 10 can be changed by adjusting the lengths of the first and second narrow portions 62, 96 and the lengths of the connecting portions, but the sliding resistance between the first and second needle tip cover portions 70, 104 and the inner needle 34 when withdrawing a 24-gauge inner needle 34 is desirably 25 gf or less, more preferably 15 gf, for example, 2 to 6 gf. By reducing the sliding resistance when withdrawing the inner needle 34 in this way, the force required to withdraw the inner needle 34 can be reduced, making it possible to easily withdraw the inner needle 34 with one hand. The 24-gauge inner needle 34 has a maximum outer diameter (outer diameter at the locking portion 42) of 0.531 mm. Therefore, the sliding resistance when the 0.531 mm engaging portion 42 passes between the first and second needle tip cover portions 70, 104 is preferably 25 gf or less, more preferably 15 gf, for example, 2 to 6 gf.

[0106] 19 , the needle tip 38 of the inner needle 34 is covered by the needle tip protector 10, which has moved toward the needle tip 38 relative to the inner needle 34. That is, when the inner needle 34 moves toward the proximal end relative to the needle tip protector 10, whose movement toward the proximal end is restricted by the outer needle hub 20, the abutment between the outer peripheral surface of the inner needle 34 and the first and second return pieces 80, 114 is released, and the first and second side plate portions 50, 52 elastically restore their shapes. The first and second side plate portions 50, 52 then deform so as to approach each other toward the distal ends, and the first needle tip cover portion 70 covers the distal end side of the inner needle 34, and the second needle tip cover portion 104 is displaced to a position covering the distal end side of the first needle tip cover portion 70, thereby achieving a needle tip protected state in which the needle tip 38 of the inner needle 34 is covered by the needle tip protector 10.

[0107] When the needle tip protector 10 is in the needle tip protection state as described above, the first tip protection piece 78 and the first return piece 80 of the first needle tip cover part 70 and the second tip protection piece 112 and the second return piece 114 of the second needle tip cover part 104 overlap each other on the tip side of the needle tip 38.

[0108] A pair of first side cover pieces 84, 84 provided on the first needle tip cover part 70 prevents the needle tip 38 from moving out of the first and second needle tip cover parts 70, 104 in the left-right direction and being exposed to the outside.

[0109] After needle tip protection activation, the first and second needle tip cover portions 70, 104 of the needle tip protector 10 approach each other, so that the first and second stepped portions 74, 108 do not engage in the front-to-rear direction with the inner circumferential surface (proximal tapered inner circumferential surface 32) of the outer needle hub 20. Therefore, when the inner needle 34 is further pulled out toward the proximal end, the locking portion 42 of the inner needle 34 locks with the bottom portion 48 of the needle tip protector 10 at the peripheral portion of the needle insertion hole 54, causing the needle tip protector 10 to move toward the proximal end together with the inner needle 34. Then, when the needle tip protector 10 is pulled out toward the proximal end from the outer needle hub 20 together with the inner needle 34, the inner needle unit 16 to which the needle tip protector 10 is attached is separated from the outer needle unit 14.

[0110] The outer needle unit 14 separated from the inner needle unit 16 is left in place as an indwelling needle inserted into a blood vessel, and an external circuit (not shown) is connected to the base end of the outer needle hub 20, thereby functioning as an access port to the blood vessel and being used, for example, as an inlet for administering infusion or medicinal fluid, or as a blood removal or return port for artificial dialysis.

[0111] 20 and 21 show a needle tip protector 130 according to a second embodiment of the present invention. The first and second side plate portions 132 and 134 of the needle tip protector 130 do not have the first and second narrow portions 62 and 96, as in the first and second side plate portions 50 and 52 of the needle tip protector 10 shown in the first embodiment. Instead, they extend linearly in the front-to-rear direction with a substantially constant left-to-right width. In this embodiment, the portions of the first and second needle tip covers 70 and 104, excluding the first and second side cover pieces 84 and 118, also have a substantially constant left-to-right width. The first and second side plate portions 132 and 134 and the first and second needle tip covers 70 and 104 have substantially the same left-to-right width. In the following description, components and parts that are substantially the same as those of the first embodiment are designated by the same reference numerals in the figures, and description thereof will be omitted. The needle tip protector 130 shown in Figures 20 and 21 is attached to the inner needle 34, with the tip sides of the first and second side plate portions 132, 134 displaced in a direction separating them from each other; however, in the stand-alone state and in the needle tip protection state, as in the first embodiment, the tip sides of the first and second side plate portions 132, 134 approach each other, and the first and second needle tip cover portions 70, 104 overlap each other in front-to-back projection.

[0112] A first side cover piece 136 that protrudes toward the second side plate 134 is integrally formed with the first side plate 132 via a first connecting portion 138. As shown in Figure 21, the first connecting portion 138 extends in one left-right direction of the first side plate 132, then folds back at its end and extends in the other left-right direction, and the first side cover piece 136 protrudes from the end of the first connecting portion 138 toward the second side plate 134. As a result, the first side cover piece 136 is located on one left-right side of the needle insertion hole 54 and on the other left-right side of one left-right end of the first side plate 132.

[0113] A second side cover piece 140 that protrudes toward the first side plate 132 is integrally formed with the second side plate 134 via a second connecting portion 142. The second connecting portion 142 extends toward the other left-right direction of the second side plate 134, then folds back at the end and extends in one of the left-right directions, and the second side cover piece 140 protrudes from the end of the second connecting portion 142 toward the first side plate 132. As a result, the second side cover piece 140 is located on the other left-right side of the needle insertion hole 54 and on one left-right side of the other left-right end of the second side plate 134.

[0114] According to the needle tip protector 130 of this embodiment having such a structure, the first and second narrow width portions 62, 96 do not need to be provided on the first and second side plate portions 132, 134; in other words, the first and second side cover pieces 136, 140 can be disposed close to the sides of the inner needle 34 regardless of the left-right width dimensions of the first and second side plate portions 132, 134, and exposure of the needle tip of the inner needle 34 in the left-right direction can be prevented in the needle tip protected state. Furthermore, the connection width dimension (front-to-back dimension in FIG. 20 ) of the first and second connecting portions 138, 142 is set to 70% or less of the maximum width dimension (front-to-back dimension in FIG. 20 ) of the first and second side cover pieces 136, 140. While the first and second side cover pieces 136, 140 are provided, the formation areas of the first and second connecting portions 138, 142 in the first and second side plate portions 50, 52 can be made smaller, thereby reducing the area of ​​high rigidity. Therefore, compared to when the maximum width dimension of the first and second side cover pieces 136, 140 and the connection width dimension of the first and second connecting portions 138, 142 are the same, the flexibility of the first and second side plate portions 50, 52 can be improved, and the resistance value when the inner needle 34 slides can be reduced.

[0115] Although the embodiments of the present invention have been described in detail above, the present invention is not limited by those specific descriptions. For example, the left-right width dimensions of the first and second narrow portions 62, 96 can vary along the length. The first and second protruding pieces 90, 124 are not essential; either one or neither may be provided. Furthermore, while it is desirable for the first and second protruding pieces 90, 124 to have a large length to effectively prevent, for example, the left and right width ends of the first and second side plate portions 50, 52 from being pressed and forcibly releasing the needle tip protection state, the length dimensions of the first and second protruding pieces 90, 124 can be equal to or less than the length dimensions of the first and second side cover pieces 86, 120.

[0116] There are no particular limitations on the specific structure of the first and second needle tip cover parts 70, 104. For example, a plate-shaped first needle tip cover part may be provided at the tip of the first side plate part 50, protruding toward the inner needle 34, generally perpendicular to the needle axial direction. A similar structure may also be adopted for the second needle tip cover part.

[0117] The side cover piece may be provided on only one side in the plate width direction (left-right width direction) of the inner needle 34. Also, for example, a pair of side cover pieces or a pair of protruding pieces may be provided on both end edge portions in the plate width direction of either the first side plate portion or the second side plate portion.

[0118] By extending at least one of the side cover pieces and the protruding piece to a position close to the bottom, for example, when multiple needle tip protectors are stored individually in a box, bottle, etc. for storage or transportation, the side cover piece or the protruding piece can prevent the needle tip cover portion of another needle tip protector from getting between a pair of opposing side plate portions.

[0119] In the above embodiment, an example was given of the storage portion 26 having an oval cross-sectional shape, but the storage portion may also be, for example, a ring having a continuous, approximately constant cross-sectional shape around its entire circumference, in which case the storage portion will have an approximately perfect circular shape in cross section that is larger than the inner diameter of the outer needle hub 20 at a position outside the storage portion.

[0120] For example, the needle tip protector of the present invention can also be applied to an indwelling needle assembly equipped with a valve structure that connects / blocks the flow path within the outer needle hub, such as that described in International Publication No. 2023 / 145968.

[0121] REFERENCE SIGNS LIST 10 Needle tip protector (first embodiment) 12 Indwelling needle assembly 14 Outer needle unit 16 Inner needle unit 18 Outer needle 20 Outer needle hub 22 Crimping pin 24 Threaded portion 26 Storage portion 28 Distal tapered inner peripheral surface 30 Straight inner peripheral surface 32 Proximal tapered inner peripheral surface 34 Inner needle (puncture needle) 36 Inner needle hub 38 Needle tip 40 Blade surface 42 Locking portion 44 Connecting portion 46 Filter cap 48 Bottom portion 50 First side plate portion (side plate portion) 52 Second side plate portion (side plate portion) 54 Needle insertion hole 56 Needle guide surface 58 Reinforcing tube portion 60 First wide portion 62 First narrow portion (narrow portion) 64 First intermediate connecting portion 66 First distal portion 68 First proximal portion 70 First needle tip cover portion (needle tip cover portion) 74 First step-shaped portion 76 First needle tip protection portion 78 First tip protection piece 80 First return piece 82 First needle tip restraining portion 84 First side cover piece 86 First side cover piece (side cover piece) 88 First connecting portion (connecting portion) 90 First protruding piece 92 First restricting piece 94 Second wide portion 96 Second narrow portion (narrow portion) 98 Second intermediate connecting portion 100 Second tip portion 102 Second base end portion 104 Second needle tip cover portion (needle tip cover portion) 108 Second step-shaped portion 110 Second needle tip protection portion 112 Second tip protection piece 114 Second return piece 116 Second needle tip restraining portion 118 Second side cover piece 120 Second side cover piece (side cover piece) 122 Second connecting portion (connecting portion) 124 Second protruding piece 126 Second restricting piece 128 Molding space 130 Needle tip protector (second embodiment) 132 First side plate portion (side plate portion) 134 Second side plate portion (side plate portion) 136 First lateral cover piece (lateral cover piece) 138 First connecting portion (connecting portion) 140 Second lateral cover piece (lateral cover piece) 142 Second connecting portion (connecting portion) L1 Length dimension of first narrow width portion L1a Length dimension of first narrow width portion on the distal side of the first connecting portion L1b Length dimension of first narrow width portion on the proximal side of the first connecting portion La Length dimension of first side plate portion L0 Total length of first side plate portion and first needle tip cover portion combined w1 Width dimension of first narrow width portion W1 Maximum width dimension of first needle tip cover portion L2 Length dimension of first needle tip cover portion w2 W2: width dimension in the front-rear direction of the first connecting portion; L3: length dimension of the second narrow portion;L3a Length dimension of the second narrow width portion on the tip side of the second connecting portion L3b Length dimension of the second narrow width portion on the base end side of the second connecting portion Lb Length dimension of the second side plate portion L0' Overall length of the second side plate portion and the second needle tip cover portion combined w3 Width dimension of the second narrow width portion W3 Maximum width dimension of the second needle tip cover portion L4 Length dimension of the second needle tip cover portion w4 Width dimension in the front-to-back direction of the second connecting portion W4 Maximum width dimension of the second side cover piece in the same direction θ1 Relative inclination angle between the first base end portion and the second base end portion in the standalone state θ2 Relative inclination angle between the first tip portion and the second tip portion in the standalone state D Distance between opposing surfaces of the first side plate portion and the second side plate portion in the vertical direction W5 Maximum outer dimension of the first needle tip cover portion and the second needle tip cover portion in the vertical direction θ1' Relative inclination angle between the first base end portion and the second base end portion in the needle attached state θ2' The relative inclination angle between the first tip portion and the second tip portion in the needle-attached state. α: The angle between the line A and the needle axis of the inner needle. β: The angle between the line B and the needle axis of the inner needle.

Claims

1. A needle tip protector which is attached to a puncture needle and prevents exposure of the needle tip by moving to the tip end where the needle tip is located, comprising a pair of side plate portions extending along the puncture needle on both sides of the puncture needle and a bottom portion connecting the base ends of the pair of side plate portions together, when attached to the puncture needle, the puncture needle is inserted through a needle insertion hole penetrating the bottom portion and is inserted between the pair of side plate portions, and the pair of side plate portions are elastically deformed toward the sides separating them from each other, a needle tip cover portion is provided at the tip side of each side plate portion and protrudes inward in the opposing direction of the pair of side plate portions, and each side plate portion is provided with a narrow width portion which has a width dimension of 70% or less of the maximum width dimension of the needle tip cover portion and is capable of flexural deformation in the opposing direction of the pair of side plate portions, The length of the narrow portion is 50% or more of the length of the side plate portion having the narrow portion.

2. A needle tip protector as described in claim 1, wherein the length dimension of each of the needle tip cover parts is 50% or more of the maximum width dimension of the needle tip cover part, and when attached to the puncture needle, the angle between the needle axis of the puncture needle and a straight line connecting the point located outermost in the opposing direction of the pair of side plate parts on the needle tip cover part and the point of contact with the puncture needle is 60 degrees or less.

3. A needle tip protector as claimed in claim 1 or 2, wherein a side cover piece is formed on each of the pair of side plate portions at one of the widthwise edge portions opposite each other in the plate width direction, protruding inward in the opposing direction, and the connection width dimension of the connection portion between the side cover piece at the widthwise edge portion of the side plate portion is 70% or less of the maximum width dimension of the side cover piece in the direction parallel to the connection width dimension.

4. A needle tip protector which is attached to a puncture needle and prevents exposure of the needle tip by moving to the tip end where the needle tip is located, comprising a pair of side plate portions extending along the puncture needle on both sides of the puncture needle and a bottom portion connecting the base ends of the pair of side plate portions together, when attached to the puncture needle, the puncture needle is inserted through a needle insertion hole penetrating the bottom portion and is inserted between the pair of side plate portions, and the pair of side plate portions are elastically deformed toward the sides separating them from each other, a needle tip cover portion is provided at the tip side of each side plate portion and protrudes inward in the opposing direction of the pair of side plate portions, and the length dimension of each needle tip cover portion is 50% or more of the maximum width dimension of the needle tip cover portion, When attached to the puncture needle, the angle between the straight line connecting the point located outermost in the opposing direction of the pair of side plate portions of the needle tip cover portion and the point of contact with the puncture needle and the needle axis of the puncture needle is 60 degrees or less.

5. A needle tip protector as claimed in any one of claims 1 to 4, wherein the positions of the base ends of the pair of needle tip cover parts are different from each other in the axial direction of the puncture needle.

6. A needle tip protector as described in claim 5, wherein an outer needle hub provided on the base end side of the outer needle that is inserted onto the puncture needle is provided with a concave accommodating portion for accommodating the pair of needle tip cover portions, and the base ends of the pair of needle tip cover portions are both located on the straight inner surface of the accommodating portion.

7. A needle tip protector which is attached to a puncture needle and prevents exposure of the needle tip by moving toward the tip end where the needle tip is located, comprising a pair of side plate portions extending along the puncture needle on both sides thereof, and when attached to the puncture needle, the puncture needle is inserted between the pair of side plate portions and the pair of side plate portions elastically deform toward the sides moving away from each other, and a needle tip cover portion is provided at the tip side of each side plate portion which protrudes inward in the opposing direction of the pair of side plate portions, and when the needle tip protector is in a standalone state not attached to the puncture needle, the distance between the opposing surfaces of the pair of side plate portions is large enough that the needle tip cover portion cannot fit in the initial shape.

8. A needle tip protector which is attached to a puncture needle and prevents exposure of the needle tip by moving toward the tip end where the needle tip is located, comprising a pair of side plate portions extending along the puncture needle on both sides of the puncture needle and a bottom portion connecting the base ends of the pair of side plate portions to each other, wherein when attached to the puncture needle, the puncture needle is inserted through a needle insertion hole penetrating the bottom portion and is inserted between the pair of side plate portions, causing the pair of side plate portions to elastically deform toward sides moving away from each other, and wherein when the needle tip protector is in a standalone state and not attached to the puncture needle, the relative inclination angle of the base end portions of the pair of side plate portions is smaller than the relative inclination angle of the tip portions of the pair of side plate portions.

9. A needle tip protector which is attached to a puncture needle and prevents exposure of the needle tip by moving toward the tip end where the needle tip is located, comprising a pair of side plate portions extending along the puncture needle on both sides of the puncture needle and a bottom portion connecting the base ends of the pair of side plate portions together, wherein when attached to the puncture needle, the puncture needle is inserted through a needle insertion hole penetrating the bottom portion and is inserted between the pair of side plate portions, causing the pair of side plate portions to elastically deform toward the sides separating them from each other, wherein the pair of side plate portions each have a side cover piece formed at one of the widthwise edge portions opposite each other in the plate width direction, the connection width dimension of the connection portion between the side cover piece at the widthwise edge portion of the side plate portion and the side cover piece is 70% or less of the maximum width dimension of the side cover piece.

10. A needle tip protector which is attached to a puncture needle and prevents the needle tip from being exposed by moving toward the tip where the needle tip is located, the needle tip protector having a plate-shaped bottom portion with a needle insertion hole through which the puncture needle is inserted, a needle guide surface having an inclined angle formed on the opening periphery of the needle insertion hole, and a pair of elastic side plate portions are provided from the bottom toward the tip.

11. A needle tip protector as claimed in claim 10, wherein the needle guide surface is formed on one of the opening peripheries of the needle insertion hole, and a cylindrical reinforcing tube portion is formed protruding from the other opening periphery of the needle insertion hole.

12. A needle tip protector which is attached to a puncture needle and prevents exposure of the needle tip by moving toward the tip end where the needle tip is located, comprising a pair of side plate portions extending along the puncture needle on both sides of the puncture needle and a bottom portion connecting the base ends of the pair of side plate portions together, wherein when attached to the puncture needle, the puncture needle is inserted through a needle insertion hole penetrating the bottom portion and is inserted between the pair of side plate portions, causing the pair of side plate portions to elastically deform toward sides moving away from each other, and wherein when attached to the puncture needle and before needle tip protection, the relative angle of inclination at the base end portions of the pair of side plate portions is greater than the relative angle of inclination at the tip end portions of the pair of side plate portions.

13. A needle tip protector which is attached to a puncture needle and prevents exposure of the needle tip by moving toward the tip end where the needle tip is located, comprising a pair of side plate portions extending along the puncture needle on both sides of the puncture needle and a bottom portion connecting the base ends of the pair of side plate portions together, wherein when attached to the puncture needle, the puncture needle is inserted through a needle insertion hole penetrating the bottom portion and is inserted between the pair of side plate portions, causing the pair of side plate portions to elastically deform toward the side separating them from each other, at least one of the pair of side plate portions has a side cover piece formed thereon which protrudes inward in the opposing direction from the widthwise edge portions of the pair of side plate portions, and wherein the connection width dimension of the connection portion at the widthwise edge portion of the side plate portion with the side cover piece is 70% or less of the maximum width dimension of the side cover piece.

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