Needle assembly

Abstract

The present invention ensures a movement stroke of a pusher toward the leading-end side thereof, while preventing the axial direction size of a needle assembly (outer-needle hub) from being large.　This needle assembly 10 comprises: an inner needle 16 which has an inner-needle hub 18 provided to the base-end side thereof; a hollow outer needle 58 which has an outer-needle hub 60 provided to the base-end side thereof; a needle tip protector 22 which protects a needle tip 20 of the inner needle 16 that has been extracted from the outer needle 58; a valve body 80 which secludes the inner cavity of the outer-needle hub 60; a pusher 84 which pushes and expands a slit 86 in the valve body 80 as a result of movement of the inner needle 16 toward the needle tip 20 side so as to cancel the seclusion of the outer-needle hub 60 by the valve body 80; and a cylindrical pusher guide 82 which guides movement of the pusher 84 toward the needle tip 20 side. The pusher 84 is provided with a pusher piece 108 that extends along the lateral side of the needle tip protector 22 toward the base end. The pusher guide 82 is provided with an insertion part 96 in which the pusher piece 108 can be inserted.

Description

needle assembly

[0001] The present invention relates to a needle assembly used for blood collection, fluid infusion (including blood transfusion), and the like.

[0002] Needle assemblies have traditionally been used in blood collection, infusion, etc. A needle assembly has a structure in which an inner needle, which has an inner needle hub attached to its proximal end, is inserted into a hollow outer needle, which has an outer needle hub attached to its proximal end. After the inner needle and outer needle are inserted into a blood vessel, the inner needle is withdrawn from the outer needle, leaving the outer needle and outer needle hub inserted in the blood vessel. An external circuit, such as a syringe or tube, is then connected to the retained outer needle hub, and blood collection, infusion, etc., is performed.

[0003] As disclosed in International Publication No. 2013 / 051242 (Patent Document 1), a needle assembly structured with a valve body that can open and close the inner lumen of the outer needle hub has also been proposed. In a needle assembly equipped with such a valve body, the inner lumen of the outer needle hub is blocked by the valve body when the inner needle is withdrawn, thereby preventing blood leakage, and when an external circuit is connected to the placed outer needle hub, the plunger moves toward the tip while being guided by the plunger guide, pushing open the valve body, thereby switching the inner lumen of the outer needle hub from a blocked state to a communicating state.

[0004] Furthermore, as disclosed in International Publication No. 2004 / 004819 (Patent Document 2), a structure has also been proposed that includes a needle tip protector that protects the tip of the inner needle when the needle is removed to prevent accidental puncture, etc. In Patent Document 2, by extending the plunger toward the base end on both sides of the needle tip protector, the axial length of the outer needle hub that houses the plunger and needle tip protector can be shortened, and the plunger can be pushed from the base end side toward the tip side when opening the valve.

[0005] International Publication No. WO 2013 / 051242 International Publication No. WO 2004 / 004819

[0006] However, in the structure of Patent Document 1, the plunger moves toward the distal end relative to the plunger guide, and therefore a gap corresponding to the movement stroke is required between the plunger and the plunger guide to prevent the plunger's movement toward the distal end from being hindered by interference with the plunger guide, which could result in an increase in the axial size of the needle assembly (outer needle hub).

[0007] Furthermore, when the plunger is extended toward the base end on both sides of the needle tip protector as in Patent Document 2, when the plunger rotates relative to the outer needle hub, the extending part of the plunger toward the base end may interfere with the needle tip protector, affecting the deformation or movement of the needle tip protector and leading to an increase in resistance when the inner needle is removed.

[0008] An object of the present invention is to provide a needle assembly having a novel structure that can solve at least one of the problems of the conventional needle assemblies described above.

[0009] 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.

[0010] The first aspect is a needle assembly comprising an inner needle having an inner needle hub on its base end, a hollow outer needle having an outer needle hub on its base end, a needle tip protector that protects the tip of the inner needle when it is removed from the outer needle, a valve body that blocks the inner cavity of the outer needle hub, a pusher that pushes open the notch in the valve body by moving the inner needle toward the needle tip, thereby releasing the blocking of the outer needle hub by the valve body, and a tubular pusher guide that guides the movement of the pusher toward the needle tip, wherein the pusher has a pusher piece that extends sideways from the needle tip protector toward the base end, and the pusher guide has an insertion portion into which the pusher piece can be inserted.

[0011] According to the needle assembly constructed in accordance with this aspect, the pushing piece of the pusher extends from the side of the needle tip protector toward the base end, so that the base end of the pusher can be set in a position that makes it easy to push it toward the tip end through the base end opening of the outer needle hub, while ensuring storage space for the needle tip protector within the outer needle hub without requiring the outer needle hub to be made larger.

[0012] Furthermore, when the plunger is pushed toward the distal end to open the valve body, the plunger guide is provided with an insertion portion into which the pusher piece of the plunger is inserted, thereby preventing interference between the pusher piece and the plunger guide from hindering the movement of the plunger toward the distal end. Therefore, the stroke of the plunger toward the distal end can be ensured without requiring an increase in the size of the outer needle hub.

[0013] In a second aspect, in the needle assembly described in the first aspect, a notch penetrating the peripheral wall of the cylindrical plunger guide from inside to outside is provided as the insertion portion.

[0014] With a needle assembly constructed in accordance with this aspect, the pusher piece of the pusher is inserted into the notch that constitutes the insertion portion with the outer periphery exposed and not covered by the pusher guide, making it easier to reduce the diameter of the pusher guide.

[0015] In this embodiment, the number of insertion portions may be one or more. When multiple insertion portions are provided, it is sufficient that at least one of the insertion portions is a notch, and the other insertion portions may have a structure different from the notch, such as a groove.

[0016] The third aspect is a needle assembly described in the first or second aspect, which is provided with a protector rotation limiting portion that is provided at the tip of the inner needle hub and inserted between the needle tip protector and the outer needle hub, and that limits the relative rotation of the needle tip protector with respect to the inner needle hub by abutment of the needle tip protector.

[0017] In a needle assembly constructed according to this aspect, if the outer needle hub and the inner needle hub are appropriately aligned in the circumferential direction, the circumferential orientation of the needle tip protector relative to the inner needle hub and further relative to the outer needle hub can be appropriately and easily set based on the action of the protector rotation limiting part. Moreover, it is possible to configure a compact protector rotation limiting part that limits the relative rotation of the needle tip protector relative to the inner needle hub within the outer needle hub.

[0018] A fourth aspect is a needle assembly comprising an inner needle having an inner needle hub on its base end, a hollow outer needle having an outer needle hub on its base end, a needle tip protector that protects the tip of the inner needle when it is removed from the outer needle, a valve body that blocks the inner cavity of the outer needle hub, a pusher that moves toward the needle tip to push open a notch in the valve body and release the blocking of the outer needle hub by the valve body, and a cylindrical pusher guide that is attached to the outer needle hub and guides the movement of the pusher toward the needle tip, wherein the pusher has a push-in piece that extends sideways from the needle tip protector toward the base end, and is provided with a rotation limiting mechanism that limits the relative rotation of the pusher with respect to the pusher guide that is assembled to and held on the outer needle hub.

[0019] In the needle assembly constructed according to this aspect, the rotation limiting mechanism limits the relative rotation of the plunger with respect to the plunger guide attached to the outer needle hub, thereby preventing easy interference (abutment) between the plunger and the needle tip protector due to relative rotation. As a result, unintended displacement of the needle tip protector due to interference of the plunger is prevented, and an increase in resistance when the inner needle is withdrawn, for example, due to the displaced needle tip protector being pressed against the inner needle, is avoided.

[0020] In a fifth aspect, in the needle assembly described in the fourth aspect, the rotation limiting mechanism is constituted by an abutment portion provided between the pusher and the pusher guide, which limits the relative circumferential rotation of the pusher and the pusher guide by abutting against each other.

[0021] With a needle assembly constructed according to this aspect, a rotation limiting mechanism can be easily realized without requiring special components or complex mechanisms.

[0022] In a fifth aspect, for example, a first rotation control surface having a smaller curvature than other parts in the circumferential direction may be provided on the outer peripheral surface of the tapered tip portion of the pusher, and a second rotation control surface overlapping the first rotation control surface may be provided on the inner peripheral surface of the pusher guide, and the abutment portion may be formed by the first rotation control surface and the second rotation control surface overlapping each other.

[0023] With a needle assembly constructed according to this aspect, a rotation limiting mechanism can be easily realized with a simple structure in which the first and second rotation limiting surfaces are superimposed on each other. Furthermore, by configuring the abutting portions that abut each other with the first and second rotation limiting surfaces, high strength and durability can be easily ensured. Furthermore, when molding the plunger and plunger guide, the first and second rotation limiting surfaces can be easily molded, which can simplify the mold structure.

[0024] In a sixth aspect, in the needle assembly described in the fifth aspect, a stepped surface is provided at the base end of the tapered tip portion of the plunger, so that the cross section of the base end of the tapered tip portion of the plunger is non-circular, and the plunger guide is provided with a retaining protrusion that abuts against the stepped surface to prevent the plunger from slipping out, and the abutment portion is formed by the protruding tip surface of the retaining protrusion of the plunger guide and the outer circumferential surface of the plunger.

[0025] In the needle assembly constructed according to this aspect, the anti-slip projection of the plunger guide, which forms an abutment portion between the plunger and the outer peripheral surface, is used to prevent the plunger from slipping out of the plunger guide toward the base end, thereby holding the plunger in an appropriate relative position with respect to the plunger guide. Furthermore, by forming an abutment portion between the protruding tip surface of the anti-slip projection and the outer peripheral surface of the plunger, it is easy to set the abutment portion at a position close to the plunger and the plunger guide, and it is possible to efficiently limit the relative rotation of the plunger with respect to the plunger guide.

[0026] In a seventh aspect, in the needle assembly described in any one of the first to sixth aspects, the inner diameter dimension of the outer needle hub is larger at the base end portion than at the tip end portion, and the portion of the pusher's pushing piece that is inserted into the base end portion of the outer needle hub has a large-diameter, thick-walled portion with a large outer diameter dimension.

[0027] In a needle assembly constructed according to this aspect, the base end of the pushing piece is formed as a large-diameter, thick-walled portion, so that when the pushing piece is pushed toward the tip side by, for example, a male connector or the like connected to the outer needle hub, a large contact area can be obtained with the male connector, etc. Furthermore, by inserting the large-diameter, thick-walled portion of the pushing piece into the base end portion of the outer needle hub where the inner diameter dimension is increased, it is possible to prevent the gap between the outer needle hub and the pushing piece from becoming excessively large.

[0028] In an eighth aspect, in the needle assembly described in any one of the first to seventh aspects, the inner peripheral edge of the base end of the plunger guide is provided with an edge expansion portion that slopes outward toward the base end.

[0029] With a needle assembly constructed according to this aspect, when the plunger is inserted into the plunger guide from the base end side, the plunger is guided by abutting against the widened end edge portion, so that the plunger can be easily positioned in an appropriate position relative to the plunger guide.

[0030] A ninth aspect is a needle assembly comprising an inner needle having an inner needle hub on its base end, a hollow outer needle having an outer needle hub on its base end, and a needle tip protector located within the outer needle hub to protect the needle tip of the inner needle when it is removed from the outer needle, wherein the inner needle hub is provided with a protector rotation limiting portion that limits the relative rotation of the needle tip protector with respect to the inner needle hub.

[0031] With a needle assembly constructed according to this aspect, the relative rotation of the needle tip protector with respect to the inner needle hub is limited by the protector rotation limiting part, so that by arranging the outer needle hub and the inner needle hub in an appropriate circumferential orientation, the circumferential orientation of the needle tip protector with respect to the outer needle hub can be easily set to an appropriate orientation. The protector rotation limiting part can be, for example, in the form of a protrusion provided on the tip of the inner needle hub, and can have a simple structure that limits the rotation of the needle tip protector by being inserted between the needle tip protector and the outer needle hub.

[0032] The tenth aspect is a needle assembly comprising an inner needle having an inner needle hub on its base end, a hollow outer needle having an outer needle hub on its base end, a needle tip protector that protects the tip of the inner needle when it is removed from the outer needle, a valve body that blocks the inner cavity of the outer needle hub, a pusher that pushes open the notch in the valve body by moving the inner needle toward the needle tip side, thereby releasing the blockage of the outer needle hub by the valve body, and a valve retaining member that holds the valve body in an attached state to the outer needle hub, wherein the pusher has a push-in piece extending sideways from the needle tip protector toward the base end, and the valve retaining member has an insertion portion into which the push-in piece can be inserted.

[0033] According to the needle assembly constructed in accordance with this aspect, the pushing piece of the pusher extends from the side of the needle tip protector toward the base end, so that the base end of the pusher can be set in a position that makes it easy to push it toward the tip end through the base end opening of the outer needle hub, while ensuring storage space for the needle tip protector within the outer needle hub without requiring the outer needle hub to be made larger.

[0034] Furthermore, when the plunger is pushed toward the distal end to open the valve body, the pusher piece of the plunger is inserted into the insertion portion provided on the valve holding member that holds the valve body, thereby preventing the movement of the plunger toward the distal end from being hindered by interference between the pusher piece and the valve holding member. Therefore, the movement stroke of the plunger toward the distal end can be secured without requiring an increase in the size of the outer needle hub.

[0035] An eleventh aspect is a needle assembly comprising: a hollow outer needle having an outer needle hub on its base end; a valve body that blocks the inner cavity of the outer needle hub; a pusher that pushes open the notch in the valve body by moving the inner needle toward the needle tip, thereby releasing the blockage of the outer needle hub by the valve body; and a cylindrical pusher guide that guides the movement of the pusher toward the needle tip, wherein the pusher guide has an insertion portion into which the pusher can be partially inserted circumferentially as the pusher moves toward the needle tip.

[0036] With the needle assembly constructed according to this aspect, when the plunger is pushed toward the distal end to open the valve, the plunger is inserted partially circumferentially into the insertion portion of the plunger guide, preventing interference between the plunger and the plunger guide from hindering the movement of the plunger toward the distal end. Therefore, the stroke of the plunger toward the distal end can be secured without requiring an increase in the size of the outer needle hub.

[0037] According to the present invention, it is possible to prevent the needle assembly (outer needle hub) from becoming larger in the axial direction, while ensuring the movement stroke of the plunger toward the tip side, and / or avoiding unintended deformation or movement of the needle tip protector.

[0038] 1 is a cross-sectional view showing a needle assembly according to a first embodiment of the present invention, corresponding to the I-I cross section of FIG. 2;

[0039] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0040] 1 to 4 show a needle assembly 10 according to a first embodiment of the present invention. The needle assembly 10 has a structure in which an inner needle unit 12 and an outer needle unit 14 are detachably connected to each other. In the following description, the front-to-rear direction (axial direction) generally refers to the left-to-right direction in FIG. 1, which is the axial direction of the inner needle 16 and the outer needle 58, which will be described later. Furthermore, generally, the distal end side refers to the left side in FIG. 1, which is the side of the needle tip 20 of the inner needle 16, which will be described later, and the proximal end side refers to the right side in FIG. 1, which is the side that is grasped and operated by the user. Furthermore, generally, the up-down direction refers to the up-down direction in FIG. 1, and the left-to-right direction refers to the left-to-right direction in FIG. 2.

[0041] The inner needle unit 12 has a structure in which an inner needle hub 18 is fixed to the proximal end side of an inner needle 16. The inner needle 16 is formed from a known material such as stainless steel, aluminum, titanium, or an alloy thereof, and is a hollow needle in this embodiment. However, the inner needle 16 may also be a solid needle. The distal end of the inner needle 16 is a sharp needle tip 20.

[0042] A needle tip protector 22 is attached to the inner needle 16. The needle tip protector 22 is formed from a metal material such as medical stainless steel. In this embodiment, the various components that make up the needle tip protector 22, which will be described later, are integrally formed, and the needle tip protector 22 can be easily manufactured by, for example, press working a metal plate.

[0043] 5 and 6, the needle tip protector 22 has a structure in which a first side plate portion 26 and a second side plate portion 28 extend from both upper and lower end edges of a bottom portion 24 located at the base end (opposite the needle tip 20) toward the needle tip 20. Note that for ease of viewing, in Figures 5 and 6, the needle tip protector 22 is shown in a state before activation (before needle tip protection), but the needle tip protector 22 may be in an activated state (needle tip protection state) when alone, and may be brought into the pre-activation state shown in Figures 5 and 6 by attaching it to the inner needle 16.

[0044] As shown in Fig. 6, the bottom portion 24 has a substantially rectangular flat plate shape and is provided with an insertion hole 30 penetrating in the plate thickness direction. A first side plate portion 26 and a second side plate portion 28 are integrally formed on a pair of opposing sides of the bottom portion 24 and extend out to one side (the tip side) in the plate thickness direction of the bottom portion 24. The first side plate portion 26 and the second side plate portion 28 in this embodiment are arranged on both the upper and lower sides of the inner needle 16 and face each other, but do not extend in a crossing manner.

[0045] The first side plate 26 has a generally rectangular plate shape overall and is elongated in the front-to-rear direction, which is the direction in which it extends from the bottom 24. The first side plate 26 includes a flat first main body 32 connected to the bottom 24, and a first needle tip protection portion 34 at the tip side of the first main body 32. The first needle tip protection portion 34 extends from the tip of the first main body 32 to the side opposite the second side plate 28, then bends at its tip and protrudes toward the tip side while inclining toward the second side plate 28, and its tip protrudes toward the bottom 24 while inclining toward the second side plate 28. A pair of side cover pieces 36, 36 extending generally perpendicular to the width direction are provided on both widthwise sides of the first needle tip protection portion 34. The first side plate 26 also includes a first side cover piece 38 extending from one widthwise edge of the first main body 32 toward the second side plate 28, and a first protruding piece 40 extending from the other widthwise edge of the first main body 32 toward the second side plate 28. The first side cover piece 38 and the first protruding piece 40 are provided on both widthwise sides of the first main body 32 and are arranged spaced apart and facing each other in the widthwise direction.

[0046] The second side plate 28 has a generally rectangular plate shape overall and is elongated in the front-to-rear direction, which is the direction of extension from the bottom 24. The second side plate 28 includes a flat second main body 42 connected to the bottom 24, and a second needle tip protection portion 44 at the distal end of the second main body 42. The second needle tip protection portion 44 extends from the distal end of the second main body 42 opposite the first side plate 26, then bends at its tip and protrudes toward the distal end while inclining toward the first side plate 26, and its distal end protrudes toward the bottom 24 while inclining toward the first side plate 26. The second side plate 28 also includes a second lateral cover piece 46 extending from one widthwise edge of the second main body 42 toward the first side plate 26, and a second protruding piece 48 extending from the other widthwise edge of the second main body 42 toward the first side plate 26. The second side cover pieces 46 and the second protruding pieces 48 are provided on both sides of the second main body portion 42 in the width direction, and are arranged to be spaced apart and opposite to each other in the width direction.

[0047] The first side cover piece 38 and the second protruding piece 48 are provided on the edge portions on the same side in the width direction of the first side plate portion 26 and the second side plate portion 28, and overlap each other in the width direction when attached to the inner needle 16 before needletip protection, with the first side cover piece 38 located at a distance inward in the width direction from the second protruding piece 48. The second side cover piece 46 and the first protruding piece 40 are provided on the edge portions on the same side in the width direction of the first side plate portion 26 and the second side plate portion 28, and overlap each other in the width direction when attached to the inner needle 16 before needletip protection, with the second side cover piece 46 located at a distance inward in the width direction from the first protruding piece 40. The first side cover piece 38 and the second side cover piece 46 are provided on opposite sides in the width direction and face each other at a distance in the width direction. In addition, the first protruding piece 40 and the second protruding piece 48 are arranged on opposite sides of each other in the width direction, facing each other at a distance in the width direction, and are located on both outer sides of the first and second side cover pieces 38, 46 in the width direction.

[0048] 1 and 2, the needle tip protector 22 is attached to the inner needle 16. That is, the inner needle 16 is inserted through the insertion hole 30 formed in the bottom 24 of the needle tip protector 22, and is also inserted between the first needle tip protection portion 34 and the second needle tip protection portion 44. As a result, the inner needle 16 is disposed so as to penetrate between the opposing first side plate portion 26 and second side plate portion 28 of the needle tip protector 22, and the needle tip protector 22 is attached in an externally fitted state to the inner needle 16. The inner needle 16 is located between the opposing first side cover piece 38 and second side cover piece 46 of the needle tip protector 22, and is surrounded around a part of the needle axis direction by the first and second side plate portions 26, 28 and the first and second side cover pieces 38, 46. The needle tip protector 22 is movable in the needle axial direction relative to the inner needle 16 , and is movable from a position adjacent to the inner needle hub 18 to a position covering the needle tip 20 of the inner needle 16 .

[0049] The inner needle hub 18 is a substantially cylindrical member made of hard synthetic resin. A cylindrical connecting portion 50 is provided at the distal end of the inner needle hub 18, which is insertable into the proximal opening of the outer needle hub 60 (described below). The connecting portion 50 has a protector rotation limiting portion 52 that protrudes distally along a portion of its circumferential direction. The needle tip protector 22 is located distally of the portion of the connecting portion 50 that is separated from the protector rotation limiting portion 52. As shown in FIG. 3 , the protector rotation limiting portion 52 extends downward from the needle tip protector 22 and overlaps the proximal end of the needle tip protector 22 (the proximal end of the second side plate portion 28) from above, below, and outward. This limits the amount of rotation of the needle tip protector 22 relative to the inner needle hub 18 by abutment between the second side plate portion 28 and the protector rotation limiting portion 52. The distal end of the inner needle hub 18 is provided with a circumferential positioning portion 54 that faces the outer periphery of the protector rotation limiting portion 52 .

[0050] 1 and 2, a filter cap 56 is attached to the proximal opening of the inner needle hub 18. The filter cap 56 is cylindrical, and the proximal opening of the lumen is covered with a breathable filter that prevents the passage of blood but allows the passage of air. This allows blood to flow from the tip of the inner needle 16 into the lumen of the inner needle hub 18, and the filter cap 56 prevents blood that has flowed into the lumen of the inner needle hub 18 from leaking to the outside.

[0051] The outer needle unit 14 has a structure in which an outer needle hub 60 is fixed to the proximal end side of an outer needle 58. The outer needle 58 is a hollow needle with an inner lumen penetrating in the axial direction. The outer needle 58 preferably has a certain degree of flexibility. The outer peripheral surface at the tip portion of the outer needle 58 may be tapered, for example, so that the diameter gradually decreases toward the tip side, thereby reducing resistance when puncturing the patient and alleviating pain, etc. Furthermore, one or more through holes may be provided in the peripheral wall at the tip portion of the outer needle 58, which can improve the efficiency of inflow and outflow of fluid into and out of the outer needle 58.

[0052] The outer needle hub 60 has a generally tubular shape extending in the axial direction as a whole, and in this embodiment, is provided with a generally cylindrical peripheral wall 62. A step 64 is provided on the inner peripheral surface of the peripheral wall 62, and the diameter of the distal side of the step 64 is smaller than the proximal side. A generally cylindrical crimping pin 66 is fixed to the inner peripheral surface of the peripheral wall 62 distal side of the step 64, and the proximal end portion of the outer needle 58 inserted into the peripheral wall 62 is sandwiched between the peripheral wall 62 and the crimping pin 66, and is bonded or welded as necessary, thereby fixing the outer needle hub 60 to the proximal end side of the outer needle 58.

[0053] The inner diameter of the peripheral wall 62 of the outer needle hub 60 is larger in the proximal portion 70 than in the distal portion 68 on the proximal side of the step 64. The proximal portion 70 of the peripheral wall 62 has a luer taper on its inner circumferential surface, with the inner diameter decreasing toward the tip. The inner diameter of the tip of the proximal portion 70 is larger than the maximum inner diameter of the distal portion 68. At the boundary between the distal portion 68 and the proximal portion 70, an annular protector engagement groove 72 is formed, opening onto the inner circumferential surface and extending in the circumferential direction. In addition, an annular recessed groove 73 extending in the circumferential direction is formed on the inner circumferential surface of the distal portion 68.

[0054] A flange-shaped portion 74 that protrudes outward is provided around substantially the entire circumference at the base end of the outer needle hub 60. A screw thread is provided on the outer peripheral surface of the flange-shaped portion 74, allowing a luer lock syringe, connector, or the like to be connected to the outer needle hub 60. In this embodiment, a positioning groove 76 that extends in the axial direction is provided on part of the circumference of the flange-shaped portion 74.

[0055] A hemostatic valve mechanism 78 is incorporated inside the outer needle hub 60. The hemostatic valve mechanism 78 includes a valve body 80, a plunger guide 82, and a plunger 84. As will be described later, when the inner needle 16 is pulled out, blood that has flowed in through the outer needle 58 is contained in an area of ​​the outer needle hub 60 distal to the hemostatic valve mechanism 78, and therefore, by making the peripheral wall 62 of the outer needle hub 60 transparent at least in the area distal to the position where the hemostatic valve mechanism 78 is disposed, the user or the like can confirm flashback from the outside.

[0056] The valve body 80 is formed from an elastic material such as rubber or elastomer, and has a notch 86 formed in its center. The outer peripheral edge of the distal surface of the valve body 80 overlaps a step 64 provided on the inner peripheral surface of the outer needle hub 60, restricting movement toward the distal end. A cylindrical support piece 88 that protrudes toward the base end is integrally formed with the valve body 80 at the outer peripheral end. A retaining groove 90 that extends annularly along the inner circumference of the support piece 88 is formed on the proximal end surface of the valve body 80. The retaining groove 90 partially includes, in the circumferential direction, an expanding portion 92 that expands radially outward over at least a portion of the circumferential direction. The valve body 80 is compressed in the radial direction when attached to the outer needle hub 60, and the inner surfaces of the notches 86 are in close contact with each other, blocking the notches 86, thereby liquid-tightly blocking the inner cavity of the outer needle hub 60 by the valve body 80.

[0057] A cylindrical plunger guide 82 is disposed on the base end side of the valve body 80. The plunger guide 82 is inserted into a support piece 88 of the valve body 80, and the support piece 88 is sandwiched radially between the outer needle hub 60 and the plunger guide 82. Furthermore, the tip of the plunger guide 82 is inserted into a holding groove 90 of the valve body 80, and the outer periphery of the valve body 80 is sandwiched axially between the step 64 of the outer needle hub 60 and the plunger guide 82. A peripheral protrusion 94 that protrudes toward the outer periphery is partially provided in the circumferential direction at the tip of the plunger guide 82 inserted into the holding groove 90, and the valve body 80 and the plunger guide 82 are positioned relative to each other in the circumferential direction by inserting the peripheral protrusion 94 into the expanded portion 92 of the holding groove 90.

[0058] The plunger guide 82 is fitted into the peripheral wall 62 of the outer needle hub 60 at a portion proximal to the insertion portion of the valve body 80 into the support piece 88, and is fixedly attached to the outer needle hub 60. As a result, the plunger guide 82 of this embodiment is a valve retaining member that holds the valve body 80 attached to the outer needle hub 60. In this embodiment, the tip of the portion of the plunger guide 82 that fits into the outer needle hub 60 protrudes slightly outward and has a large diameter, and when assembling the plunger guide 82 to the outer needle hub 60, a clicking sensation is felt when the large diameter portion of the plunger guide 82 is inserted into the recessed groove 73 provided on the inner peripheral surface of the outer needle hub 60, making it easy to know that the plunger guide 82 has been arranged in an appropriate axial position relative to the outer needle hub 60.

[0059] The plunger guide 82 of this embodiment is fitted onto the inner peripheral surface of the outer needle hub 60 and is indirectly pressed against the outer needle hub 60 via the valve body 80, which is an elastic body, and the positioning action of the plunger guide 82 with respect to the outer needle hub 60 is exerted by the frictional resistance force acting between the plunger guide 82 and the valve body 80, which has a large coefficient of friction. As a result, even if an external force such as a rotational force is applied from the plunger 84 to the plunger guide 82 when, for example, the plunger 84 described below is pushed toward the tip side, movement such as relative rotation of the plunger guide 82 with respect to the outer needle hub 60 is prevented.

[0060] As shown in Figures 7 and 8, the base end portion of the plunger guide 82 has a pair of notches 96, 96. The notches 96, 96 as insertion portions are formed on both the left and right sides of the plunger guide 82, penetrating the base end portion of the plunger guide 82 in the left-right direction, respectively. By forming such a pair of notches 96, 96, the base end portion of the plunger guide 82 becomes a pair of guide pieces 98, 98 located circumferentially between the pair of notches 96, 96, which are positions circumferentially offset from the pair of notches 96, 96. The pair of guide pieces 98, 98 are arranged opposite each other in the vertical direction and have approximately symmetrical shapes. The outer peripheral surface of the guide piece 98 has an arc-shaped cross section corresponding to the inner peripheral surface of the outer needle hub 60, and the inner peripheral surface serves as a guide-side flat surface 100 serving as a second rotation-restricting surface with a smaller curvature than the outer peripheral surface. In this embodiment, the guide-side flat surface 100 has a planar shape. The guide piece 98 has an inner peripheral surface with a smaller curvature than an outer peripheral surface, so that the guide piece 98 is thicker toward the center in the circumferential direction.

[0061] At the distal ends of the pair of guide pieces 98, 98, groove-shaped recesses 102, 102 extending in the axial direction with an arc-shaped cross section are formed, opening onto the inner circumferential surface. The inner surface of the groove-shaped recess 102 is located on an extension of the inner circumferential surface of the plunger guide 82 distal to the guide piece 98. The groove-shaped recess 102 does not reach the proximal end of the guide piece 98. A retaining projection 104 is provided on the guide piece 98 proximal to the groove-shaped recess 102, projecting inward in the opposing direction of the pair of guide pieces 98, 98. The retaining projection 104 has a distal (needle tip 20) surface that widens in the axis-perpendicular direction, and a proximal surface that forms a tapered edge expansion portion 105 that slopes outward toward the proximal end. As shown in FIG. 8 , the edge expansion portion 105 in this embodiment has both left and right side portions formed by flat surfaces, and a central portion in the left and right direction that has an arc-shaped cross section. The protruding tip surfaces (upper and lower inner end surfaces) of the retaining projections 104 are formed by part of the guide-side flat surface 100 and are flat surfaces that extend approximately perpendicular to the vertical direction.

[0062] A plunger 84 is inserted into the plunger guide 82. The plunger 84 is formed, for example, from a hard synthetic resin, and as shown in Figures 9 and 10, the distal end of the plunger 84 is a cylindrical insertion tube portion 106 that extends in the needle axial direction, and has a pair of pushing pieces 108, 108 on the proximal end side of the insertion tube portion 106.

[0063] The insertion tube portion 106 has a tapered tip portion 110 with a tapered outer circumferential surface whose diameter decreases toward the tip, and a flat base portion 112 whose base portion extends in the needle axial direction with a substantially constant cross-sectional shape. The inner circumferential surface of the insertion tube portion 106 is a cylindrical surface extending in the needle axial direction with a substantially constant diameter dimension over its entire length. Therefore, the tapered tip portion 110 of the insertion tube portion 106 becomes thinner toward the tip.

[0064] The flat base end portion 112 of the plunger 84 has a pair of upper and lower plunger-side flat surfaces 114, 114 on its outer circumferential surface. The plunger-side flat surface 114 is formed as a plane extending approximately perpendicular to the up-down direction, and the cross-sectional shape of the flat base end portion 112 is a flat shape in which the outer dimension in the up-down direction is smaller than the outer dimension in the left-right direction. As a result, the base end of the tapered tip portion 110 protrudes outward above and below the flat base end portion 112 on both the upper and lower sides where the plunger-side flat surface 114 is formed, and a step surface 116 extending in the axis-perpendicular direction is formed at the base end of the tapered tip portion 110 at the boundary with the flat base end portion 112. In this embodiment, the length of the flat base end portion 112 is shorter than the length of the tapered tip portion 110, and preferably the length of the flat base end portion 112 is in the range of ¼ to ¾ of the length of the tapered tip portion 110. Since the inner peripheral surface of the flat base end portion 112 is a cylindrical surface, the radial thickness dimension of the flat base end portion 112 is smaller in the portion where the plunger side flat surface 114 is formed than in other portions.

[0065] A pair of pusher pieces 108, 108 are integrally provided on the plunger 84 closer to the base end than the flat base end portion 112. The pusher pieces 108 are partially provided in the circumferential direction at the base end portion of the plunger 84, with the left and right outer surfaces being curved surfaces with arc-shaped cross sections and the left and right inner surfaces being flat surfaces extending approximately perpendicular to the left and right direction, and becoming thicker toward the center in the up-down direction. The tip portion of the pusher piece 108 is bent inward in the left-right direction and is integrally connected to the base end of the flat base end portion 112. In other words, the pair of pusher pieces 108, 108 extend outward in the left-right direction from the base end of the flat base end portion 112, and are bent at both left and right outer ends to extend toward the base end. Furthermore, the bent tip portion of the pushing piece 108 has a tapered shape in which the base end surface is inclined outward to the left and right, and thick reinforcement portions 118 are provided at the corners, improving strength and durability. The tip portion of the pushing piece 108 has a shape and size that allows it to be inserted axially from the base end side into the notch 96 of the plunger guide 82.

[0066] The base end of the pushing piece 108 has an outer peripheral surface with an arc-shaped cross section that is larger in diameter than the tip end, thereby forming a thick-walled large-diameter thick-walled portion 120. The large-diameter thick-walled portion 120 of the pushing piece 108 is inserted into the base end portion 70 of the outer needle hub 60, which has a larger inner diameter, in a state where it can move toward the tip. By providing the large-diameter thick-walled portion 120 at the base end of the pushing piece 108, the gap between the pushing piece 108 and the outer needle hub 60 is reduced, even in the base end portion 70 of the outer needle hub 60, which has a larger inner diameter, and this makes it possible to avoid damage due to excessive deformation of the pushing piece 108, for example, when the pushing piece 108 is pushed toward the tip, as described below.

[0067] 1 and 2 , the inserting tube portion 106 of the plunger 84 is inserted into the plunger guide 82, and a stepped surface 116 formed at the base end of the tapered tip portion 110 of the inserting tube portion 106 is engaged in the axial direction with the retaining protrusion 104 of the plunger guide 82. This limits the amount of movement of the plunger 84 toward the base end relative to the plunger guide 82, and the engagement between the retaining protrusion 104 and the stepped surface 116 prevents the plunger 84 from coming off the plunger guide 82. When the inserting tube portion 106 of the plunger 84 is inserted into the plunger guide 82, the outer peripheral surface of the tapered tip portion 110 and the expanded edge portion 105, which is the surface on the base end side of the retaining protrusion 104, are each tapered, making it easier for the stepped surface 116 of the plunger 84 to ride over the retaining protrusion 104 of the plunger guide 82 from the base end side to the tip side.

[0068] 4, the guide-side flat surfaces 100, 100 including the protruding tip surface of the anti-detachment protrusion 104 of the plunger guide 82 are overlapped in the vertical direction with the plunger-side flat surfaces 114, 114 of the plunger 84. As a result, the amount of relative rotation between the plunger 84 and the plunger guide 82 about the central axis (needle axis) is limited by an abutment portion formed by the abutment between the plunger-side flat surface 114, which is the first rotation limiting surface, and the guide-side flat surface 100, which is the second rotation limiting surface. In this way, in this embodiment, a rotation limiting mechanism that limits the amount of relative rotation between the plunger 84 and the plunger guide 82 is realized with a simple structure by the abutment between the guide-side flat surface 100 and the plunger-side flat surface 114.

[0069] The relative circumferential rotation of the pusher 84 with respect to the pusher guide 82 is restricted by the rotation restriction mechanism, and the relative circumferential rotation of the pusher guide 82 with respect to the outer needle hub 60 is restricted, thereby restricting the relative circumferential rotation of the pusher 84 with respect to the outer needle hub 60. Therefore, the pusher 84 and the pusher guide 82 are housed inside the outer needle hub 60 in a state where they are positioned in a predetermined orientation in the circumferential direction with respect to the outer needle hub 60.

[0070] The guide-side flat surface 100 of the pusher guide 82 and the pusher-side flat surface 114 of the pusher 84 can both be easily formed without causing problems such as interfering with mold separation when molding the pusher guide 82 and the pusher 84, and a rotation limiting mechanism can be easily obtained. Furthermore, by configuring the rotation limiting mechanism by abutting the surfaces together, it is easy to ensure strength and durability against abutment pressure.

[0071] 1 and 2 , the inner needle unit 12 and the outer needle unit 14 are combined with each other with the inner needle 16 inserted into the outer needle 58 to form the needle assembly 10. The inner needle 16 is inserted into the outer needle hub 60 from the proximal opening, passes through the slit 86 in the valve body 80, and is inserted into the outer needle 58. The connecting part 50 of the inner needle hub 18, including the protector rotation limiting part 52, is inserted into the proximal opening of the outer needle hub 60, so that the inner needle hub 18 and the outer needle hub 60 are positioned relative to each other to a certain extent, and the inner needle hub 18 is movable toward the proximal end relative to the outer needle hub 60.

[0072] 3 , in the needle assembly 10, the circumferential positioning portion 54 of the inner needle hub 18 is inserted into a positioning groove 76 provided on the flange-shaped portion 74 of the outer needle hub 60. As a result, the amount of relative rotation between the inner needle hub 18 and the outer needle hub 60 is limited by the abutment between the circumferential positioning portion 54 and the flange-shaped portion 74. Furthermore, since the amount of relative rotation of the needle tip protector 22 with respect to the inner needle hub 18 is limited by the abutment with the protector rotation limiting portion 52, its relative rotation with respect to the outer needle hub 60 is limited, and the needle tip protector 22 is positioned circumferentially with respect to the outer needle hub 60. Therefore, in the needle assembly 10, the relative rotation of the needle tip protector 22, the plunger guide 82, and the plunger 84, whose relative rotation with respect to the outer needle hub 60 is limited, is limited, and they are positioned relative to each other in the circumferential direction.

[0073] In the needle assembly 10, the needle tip protector 22 attached to the inner needle 16 is inserted into the inner cavity of the outer needle hub 60 and positioned within the outer needle hub 60, as shown in Figures 1 and 2, and is disposed on the proximal end side of the plunger 84. More specifically, the needle tip protector 22 is disposed between the opposing pair of pushing pieces 108, 108 of the plunger 84 in the inner cavity of the outer needle hub 60, as shown in Figure 2. In other words, the insertion tube portion 106 of the plunger 84 is positioned on the distal end side of the needle tip protector 22, and the pair of pushing pieces 108, 108 of the plunger 84 extend out from both sides in the width direction of the needle tip protector 22 towards the proximal end.

[0074] In this way, the base end portion of the plunger 84 is bifurcated and made up of a pair of pushing pieces 108, 108 arranged opposite each other, and the needle tip protector 22 is inserted between the pair of pushing pieces 108, 108. This allows the length of the outer needle hub 60 to be shorter than when the needle tip protector 22 and the plunger 84 are arranged in series without overlapping when projected in the direction perpendicular to the axis.

[0075] Furthermore, no pushers 84 are arranged on either side of the opposing direction (up and down direction) of the first and second side plate portions 26, 28 of the needle tip protector 22, and the first and second side plate portions 26, 28 are exposed to the outer periphery through the opening between the circumferential direction of the pair of pushing pieces 108, 108. This allows the outer needle hub 60 to have a smaller diameter than when parts of the pushers are arranged on both the top and bottom sides of the needle tip protector 22, and also ensures an appropriate stroke for the approaching displacement of the first and second side plate portions 26, 28 when the needle tip protector 22 is activated, as described below.

[0076] The needle tip protector 22 protrudes further outward than the pair of pushing pieces 108, 108 in an axis-perpendicular direction (up-down direction) that is approximately perpendicular to the opposing direction (left-right direction) of the pair of pushing pieces 108, 108 (see FIG. 1 ). The first needle tip protecting part 34 and the second needle tip protecting part 44 of the needle tip protector 22 are inserted into a protector locking groove 72 formed on the inner surface of the outer needle hub 60, and resistance to movement of the needle tip protector 22 toward the base end relative to the outer needle hub 60 is exerted by contact between the first needle tip protecting part 34 and the second needle tip protecting part 44 and the inner surface of the protector locking groove 72. The resistance force against the movement of the needle tip protector 22 toward the base end relative to the outer needle hub 60 is not limited to the above-described mode in which it is exerted by direct contact of the needle tip protector 22 with the outer needle hub 60, and can also be exerted, for example, by the needle tip protector 22 indirectly contacting the outer needle hub 60 via another member. Specifically, for example, the resistance force may be exerted by the needle tip protector 22 coming into contact with a plunger 84 or plunger guide 82 whose movement toward the base end relative to the outer needle hub 60 is restricted.

[0077] Furthermore, the first and second protruding pieces 40, 48 of the needle tip protector 22 are arranged close to the opposing inner surfaces of the pair of pushing pieces 108, 108 of the plunger 84. In this embodiment, the opposing surfaces of the first and second protruding pieces 40, 48 and the pushing pieces 108, 108 are all flat, and the abutment of these opposing surfaces limits the amount of relative rotation between the needle tip protector 22 and the plunger 84. Since the amount of relative rotation of the plunger 84 with respect to the outer needle hub 60 is limited via the plunger guide 82, the amount of rotation of the needle tip protector 22 with respect to the outer needle hub 60 is limited via the plunger 84 and the plunger guide 82.

[0078] In the needle assembly 10 constructed as described above, the inner needle 16 and the outer needle 58 are inserted into a blood vessel. When the blood vessel is punctured, blood flows into the lumen of the inner needle hub 18 through the lumen of the inner needle 16. Therefore, by making the inner needle hub 18 transparent or semi-transparent so that the interior can be seen, it is possible to confirm that the inner needle 16 has punctured the blood vessel by checking the flow of blood into the inner needle hub 18.

[0079] After the inner needle 16 and the outer needle 58 have punctured the blood vessel, the inner needle unit 12 is pulled toward the proximal end while the outer needle unit 14 is held in the puncture position, thereby withdrawing the inner needle 16 toward the proximal end from the outer needle 58. At this time, the connection between the inner needle hub 18 and the outer needle hub 60 is released, and the entire inner needle unit 12 is separated from the outer needle unit 14, as shown in Figures 11 and 12 . The outer needle unit 14 separated from the inner needle unit 12 is in a state of having punctured the blood vessel, but because the inner needle 16 is withdrawn from the slit 86 of the valve body 80, the slit 86 of the valve body 80 is liquid-tightly sealed, and the lumen of the outer needle hub 60 is blocked by the valve body 80, making it difficult for blood flowing into the outer needle hub 60 through the outer needle 58 to leak out toward the proximal end of the outer needle hub 60.

[0080] When the inner needle 16 moves toward the base end relative to the outer needle hub 60, the first needle tip protection portion 34 and the second needle tip protection portion 44 of the needle tip protector 22 are restricted from moving toward the base end by the protector locking groove 72 of the outer needle hub 60, and therefore the needle tip protector 22 moves toward the tip end side of the inner needle 16. When the inner needle 16 moves to the base end side of the first and second needle tip protection portions 34, 44 of the needle tip protector 22 and the abutment between the inner needle 16 and the first and second needle tip protection portions 34, 44 is released, the first and second side plate portions 26, 28 move inward in the opposing direction so as to approach each other. As a result, the first and second needle tip protection parts 34, 44 move to a position where they cover the tip side of the inner needle 16, so that the needle tip 20 of the inner needle 16 is protected by the first and second needle tip protection parts 34, 44, and the needle tip protector 22 prevents the inner needle 16 from being re-exposed at the tip side.

[0081] Furthermore, as the first and second needle tip protection parts 34, 44 move closer together, the engagement between the first and second needle tip protection parts 34, 44 and the protector engagement groove 72 of the outer needle hub 60 is released, allowing the needle tip protector 22 to move toward the base end relative to the outer needle hub 60. Then, the partially enlarged diameter portion provided near the tip of the inner needle 16 is engaged in the axial direction with the peripheral edge of the insertion hole 30 in the bottom 24 of the needle tip protector 22, causing the needle tip protector 22, which has protected the needle tip 20 of the inner needle 16, to move toward the base end integrally with the inner needle 16 and separate from the outer needle hub 60. Therefore, the inner needle unit 12 separated from the outer needle unit 14 is in a needle tip-protected state in which the needle tip 20 of the inner needle 16 is housed in the needle tip protector 22, thereby avoiding problems such as accidentally touching the needle tip 20 and achieving excellent safety. With the needle tip 20 protected by the needle tip protector 22 in this manner, the inner needle 16 is surrounded by the first and second main body portions 32, 42, the first and second side cover pieces 38, 46, and the first and second projecting pieces 40, 48 of the needle tip protector 22, preventing, for example, exposure of the needle tip 20 due to tilting of the inner needle 16. Furthermore, because the side opening of the first needle tip protecting portion 34 is covered by the side cover pieces 36, 36, exposure of the needle tip 20 is more effectively prevented.

[0082] The outer needle unit 14 separated from the inner needle unit 12 is left as an indwelling needle, punctured into a blood vessel, and as shown in Figures 13 and 14 , an external circuit 122 is connected to the proximal end side of the outer needle hub 60. The external circuit 122 is constituted by, for example, a tube or a syringe, and the figures show a male connector 124 that constitutes the connecting end of the external circuit 122 to the outer needle hub 60. The male connector 124 has a luer taper on its outer peripheral surface that corresponds to the inner peripheral surface of the proximal end portion 70 of the outer needle hub 60, allowing it to be inserted into and fitted with the proximal end portion 70. The connecting end of the external circuit 122 to the outer needle hub 60 may be provided with a locking portion that screws onto the flange-shaped portion 74 of the outer needle hub 60.

[0083] When the male connector 124 is inserted into the outer needle hub 60 from the base end side, the tip of the male connector 124 is pressed against the pair of pushing pieces 108, 108 of the plunger 84, and the plunger 84 is pushed toward the tip side. The plunger 84 moves toward the tip side while being guided in the axial direction by the insertion tube portion 106 sliding against the inner circumferential surface of the plunger guide 82, which includes the groove-like recess 102. The plunger 84 is also guided in the axial direction by the sliding contact between the plunger-side flat surfaces 114, 114 provided on both the upper and lower sides of the plunger 84 and the guide-side flat surfaces 100, 100 provided on both the upper and lower sides of the plunger guide 82.

[0084] In the present embodiment, the pair of pushing pieces 108, 108 of the plunger 84 are provided on the sides of the needle tip protector 22, extending out toward the base end, so that the protector locking groove 72 of the outer needle hub 60, which is the locking portion for the first and second needle tip protection parts 34, 44 of the needle tip protector 22, is provided on the distal side, and the plunger 84 can be sufficiently pushed toward the distal side by the external circuit 122 (male connector 124) when connecting the external circuit 122 to the outer needle unit 14. As a result, for example, stable needle tip protection by the needle tip protector 22 and reliable opening operation of the valve mechanism can both be achieved.

[0085] The pushing piece 108 has a large-diameter, thick-walled portion 120 at its base end against which the male connector 124 is pressed, which increases the contact area with the male connector 124 and ensures strength (durability) against the contact. Furthermore, because the base end of the pushing piece 108, which is inserted into the base end portion 70, which has a large inner diameter, of the outer needle hub 60, is the large-diameter, thick-walled portion 120 with a large outer diameter, the radial gap between the pushing piece 108 and the outer needle hub 60 is small and the amount of flexural deformation when the pushing piece 108 is pushed is limited, thereby avoiding damage to the pushing piece 108 when it is pushed.

[0086] As the plunger 84 moves toward the tip side, the insertion tube portion 106 of the plunger 84 is inserted into the notch 86 of the valve body 80 while pushing the notch 86 open. This places the tip opening of the outer needle 58 and the external circuit 122 in communication with each other through the inner cavity of the insertion tube portion 106. In this way, the inner cavity of the outer needle hub 60 is blocked by the valve body 80 before the external circuit 122 is connected, and is switched to a communicating state when the external circuit 122 is connected and the notch 86 is pushed open by the plunger 84. Then, when the internal flow path of the outer needle unit 14 is unblocked by the valve body 80, the outer needle unit 14 functions as an access port to a blood vessel and can be used, for example, as an administration port for infusions or medicinal solutions, a blood collection port or blood return port for artificial dialysis, etc. The insertion tube portion 106 of the plunger 84 has a tapered shape in which the outer circumferential surface of the tapered tip portion 110 becomes smaller in diameter toward the tip, making it easy to insert into the notch 86 of the valve body 80 .

[0087] When the pusher 84 moves toward the tip side, interference between the pair of pusher pieces 108, 108 of the pusher 84 that protrude on both the left and right sides and the pusher guide 82 is avoided, and a sufficient movement stroke toward the tip side of the pusher 84 is ensured. In other words, by inserting the pair of pusher pieces 108, 108 of the pusher 84 into the pair of notches 96, 96 formed in the pusher guide 82, the pair of pusher pieces 108, 108 can move toward the tip side without interfering with the pusher guide 82.

[0088] Because the amount of relative rotation in the circumferential direction between the plunger 84 and the plunger guide 82 is limited by the rotation limiting mechanism, the pair of pushing pieces 108, 108 of the plunger 84 are positioned at positions where they can be inserted into the pair of notches 96, 96 of the plunger guide 82. In this way, because the pair of pushing pieces 108, 108 of the plunger 84 are positioned with the pair of notches 96, 96 of the plunger guide 82, reliability of the opening operation of the valve mechanism by movement of the plunger 84 toward the tip side is ensured, and movement of the plunger 84 toward the tip side relative to the plunger guide 82 is permitted over a large movement stroke.

[0089] Furthermore, the axial movement of the plunger 84 is also guided by the pair of guide pieces 98, 98 of the plunger guide 82, so that the plunger 84 can be guided in the axial direction by the plunger guide 82 while ensuring a large movement stroke of the plunger 84 toward the tip side.

[0090] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the specific descriptions. For example, the rotation limiting mechanism is not necessarily limited to one formed by the abutment of overlapping flat surfaces. For example, the rotation limiting mechanism can be formed by engagement between protrusions or engagement between a convex portion and the inner surface of a concave portion.

[0091] When the abutment portion constituting the rotation limiting mechanism is constituted by a first rotation limiting surface on the plunger 84 side and a second rotation limiting surface on the plunger guide 82 side, these first and second rotation limiting surfaces are not limited to flat surfaces such as the guide-side flat surface 100 and the plunger-side flat surface 114 shown in the above embodiment. That is, the abutment portion may be constituted by any surface as long as it can limit the relative rotation of the plunger 84 and the plunger guide 82 by abutment between them, and may be constituted by, for example, a curved surface. Specifically, for example, if the curvature of the outer circumferential surface of the plunger 84 and the curvature of the inner circumferential surface of the plunger guide 82 are smaller than the curvature of a circle about the central axis on the first and second rotation limiting surfaces, the relative rotation of the plunger 84 and the plunger guide 82 can be limited by abutment of the curved surfaces. In short, the first rotation control surface and the second rotation control surface can be constructed, for example, by partially reducing the curvature of the outer surface of the pusher 84 and the inner surface of the pusher guide 82, which are superimposed on each other, in the circumferential direction.

[0092] Although a pair of pushing pieces 108 are preferably provided opposite each other as in the above embodiment, there may be only one, or three or more guide pieces 98 spaced apart in the circumferential direction. Similarly, the number of guide pieces 98 of the plunger guide 82 may be only one, or three or more guide pieces 98 spaced apart in the circumferential direction. The number of pushing pieces 108 and the number of guide pieces 98 are preferably the same, but may be different.

[0093] There are no particular limitations on the specific structure of the protector rotation limiting portion 52 that limits the rotation of the needle tip protector 22. Specifically, for example, a protruding protector rotation limiting portion that protrudes from the tip of the inner needle hub 18 may be inserted into a recess or hole formed in the bottom portion 24 of the needle tip protector 22, thereby limiting the rotation of the needle tip protector 22 relative to the inner needle hub 18. Furthermore, the protector rotation limiting portion 52 that is superimposed on the side surface of the needle tip protector 22 shown in the above embodiment may be provided at multiple locations in the circumferential direction, thereby more effectively exerting the rotation limiting effect.

[0094] The structure of the needle tip protector 22 is not limited to the specific example shown in the above embodiment. That is, for example, a needle tip protector can be employed that includes a protector main body that is disposed on the outer periphery of the inner needle 16 and biased by magnetic force or the like in a direction to be pressed against the outer periphery of the inner needle 16, and that moves to a position covering the distal end of the inner needle 16 when the inner needle 16 is withdrawn. In this case, the pushing piece 108 of the plunger 84 is disposed so as to extend toward the base end along the side of the protector housing that holds the protector main body. Furthermore, a flexible piece extending from the protector housing that houses the protector main body can pass along the side of the plunger and be engaged in a groove or the like on the inner surface of the outer needle hub. Furthermore, the needle tip protector is not limited to one that covers only the distal end portion of the inner needle 16, but may be one that covers the entire inner needle 16 when housed.

[0095] The insertion portion of the pusher guide 82 into which the pusher piece 108 is inserted when the pusher 84 moves toward the tip side is not necessarily limited to the notch 96 that penetrates the pusher guide 82 in the radial direction, but may be, for example, a groove that opens into the inner peripheral surface of the pusher guide 82. Furthermore, when multiple insertion portions are provided, the multiple insertion portions may have different structures from each other, for example, at least one of the insertion portions may be the notch 96 and at least one of the other insertion portions may be a groove.

[0096] In the above embodiment, an example was shown in which the plunger guide 82 was attached to the outer needle hub 60 as a separate body, but it is also possible to configure the plunger guide using the outer needle hub, for example, by configuring it from two parts and setting the function of guiding the plunger 84 on one of the two parts. Also, in the above embodiment, the plunger guide 82 had the function of guiding the plunger 84 as well as the function of serving as a valve holding member that holds the valve body 80, but for example, a valve holding member that does not have the function of guiding the plunger 84 can be provided with an insertion portion into which the pushing piece 108 is inserted when the plunger 84 moves forward.

[0097] REFERENCE SIGNS LIST 10 needle assembly 12 inner needle unit 14 outer needle unit 16 inner needle 18 inner needle hub 20 needle tip 22 needle tip protector 24 bottom 26 first side plate portion 28 second side plate portion 30 insertion hole 32 first main body portion 34 first needle tip protection portion 36 side covering piece 38 first side cover piece 40 first protruding piece 42 second main body portion 44 second needle tip protection portion 46 second side cover piece 48 second protruding piece 50 connecting portion 52 protector rotation limiting portion 54 circumferential positioning portion 56 filter cap 58 outer needle 60 outer needle hub 62 peripheral wall 64 step 66 crimping pin 68 distal end portion 70 proximal end portion 72 protector engagement groove 73 concave groove 74 flange-shaped portion 76 Positioning groove 78 Hemostatic valve mechanism 80 Valve body 82 Plunger guide 84 Plunger 86 Notch (insertion portion) 88 Support piece 90 Retaining groove 92 Expanded portion 94 Outer peripheral protrusion 96 Notch 98 Guide piece 100 Guide-side flat surface (second rotation restriction surface) 102 Groove-shaped recess 104 Removal prevention protrusion 105 End edge expansion portion 106 Insertion tube portion 108 Push-in piece 110 Tapered tip portion 112 Flat base end portion 114 Plunger-side flat surface (first rotation restriction surface) 116 Step surface 118 Reinforcement portion 120 Large-diameter thick portion 122 External circuit 124 Male connector

Claims

1. An inner needle with an inner needle hub provided on the base end, A hollow outer needle with an outer needle hub provided at the base end, A needle tip protector that protects the needle tip of the inner needle after it has been removed from the outer needle, A valve body that blocks the lumen of the outer needle hub, A plunger that, by moving the inner needle toward the needle tip, expands the notch in the valve body and releases the valve body from blocking the outer needle hub, A cylindrical plunger guide that guides the plunger toward the needle tip, A needle assembly comprising, The plunger is provided with a pressing piece that extends from the side of the needle tip protector toward the base end, The aforementioned plunger guide is a needle assembly having an insertion portion into which the plunger piece can be inserted.

2. The needle assembly according to claim 1, wherein a notch is provided as the insertion portion that penetrates the peripheral wall of the cylindrical plunger guide from the inside to the outside.

3. The needle assembly according to claim 1 or 2, wherein a protector rotation limiting part is provided at the tip of the inner needle hub and inserted between the needle tip protector and the outer needle hub, and the relative rotation of the needle tip protector with respect to the inner needle hub is limited by contact with the needle tip protector.

4. An inner needle with an inner needle hub provided on the base end, A hollow outer needle with an outer needle hub provided at the base end, A needle tip protector that protects the needle tip of the inner needle after it has been removed from the outer needle, A valve body that blocks the lumen of the outer needle hub, A plunger that, by moving toward the needle tip, expands the notch in the valve body and releases the valve body from blocking the outer needle hub, A cylindrical plunger guide attached to the outer needle hub that guides the plunger's movement toward the needle tip, A needle assembly comprising, The plunger is provided with a pressing piece that extends from the side of the needle tip protector toward the base end, A needle assembly is provided with a rotation limiting mechanism that limits the relative rotation of the plunger with respect to the plunger guide, which is assembled to and held on the outer needle hub.

5. The needle assembly according to claim 4, wherein the rotation limiting mechanism is configured by a contact portion provided between the plunger and the plunger guide, which limits the relative rotation of the plunger and the plunger guide in the circumferential direction by mutual contact.

6. The base end of the tapered tip portion of the plunger is provided with a stepped surface, and the cross-section of the base end of the tapered tip portion of the plunger is not perfectly circular. Furthermore, the plunger guide is provided with a retaining projection that prevents the plunger from coming out by contacting the stepped surface. The needle assembly according to claim 5, wherein the contact portion is formed by the protruding tip surface of the retaining projection of the plunger guide and the outer circumferential surface of the plunger.

7. The inner diameter of the outer needle hub is larger at the base end than at the tip end. The needle assembly according to any one of claims 1, 2, and 4 to 6, wherein the portion of the pusher's push piece that is inserted into the base end portion of the outer needle hub has a large diameter and thick wall portion.

8. The needle assembly according to any one of claims 1, 2, and 4 to 6, wherein the base end inner periphery of the plunger guide is provided with an edge widening portion that slopes outward toward the base end.

9. An inner needle with an inner needle hub provided on the base end, A hollow outer needle with an outer needle hub provided at the base end, A needle tip protector located within the outer needle hub protects the needle tip of the inner needle when it is removed from the outer needle. A needle assembly comprising, The needle assembly is provided with a protector rotation limiting section in the inner needle hub that limits the relative rotation of the needle tip protector with respect to the inner needle hub.

10. An inner needle with an inner needle hub provided on the base end, A hollow outer needle with an outer needle hub provided at the base end, A needle tip protector that protects the needle tip of the inner needle after it has been removed from the outer needle, A valve body that blocks the lumen of the outer needle hub, A plunger that, by moving the inner needle toward the needle tip, expands the notch in the valve body and releases the valve body from blocking the outer needle hub, A valve holding member that holds the valve body in an attached state to the outer needle hub, A needle assembly comprising, The plunger is provided with a pressing piece that extends from the side of the needle tip protector toward the base end, The valve holding member is a needle assembly having an insertion portion into which the push-in piece can be inserted.

11. An inner needle with an inner needle hub provided on the base end, A hollow outer needle with an outer needle hub provided at the base end, A valve body that blocks the lumen of the outer needle hub, A plunger that, by moving the inner needle toward the needle tip, expands the notch in the valve body and releases the valve body from blocking the outer needle hub, A cylindrical plunger guide that guides the plunger toward the needle tip, A needle assembly comprising, The plunger guide is a needle assembly having an insertion portion into which the plunger is partially inserted in the circumferential direction as the plunger moves toward the needle tip.