Needle assembly

Abstract

To realize a needle assembly with high operation stability when canceling engagement of a needle tip protector.SOLUTION: A needle assembly 100 includes: an outer needle unit 101; an inner needle unit 102; a connector cap 103; and a needle tip protector 104 which is held by the connector cap 103 so as to store a needle tip 123, and is to be separated from the connector cap 103 together with the inner needle unit 102. The needle tip protector 104 includes an engagement part 145 which is regulated in position by a closing part 143, and whose regulation is canceled by a relative movement of the closing part 143, so as to enable canceling of engagement with the connector cap 103. The engagement part 145 includes an engagement projection 181 which is projected outward in a radial direction, and can be moved from an engagement position for engagement with an inner surface of the connector cap 103 to a cancel position to cancel the engagement with the inner surface of the connector cap 103 on a radially inner side from the engagement position.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a needle assembly, and more particularly to an indwelling needle having a safety mechanism for protecting the needle tip after use. [Background technology]

[0002] In dialysis treatment and the like, an indwelling needle may be inserted and left in a blood vessel. When inserting an indwelling needle, a needle assembly is used in which an inner needle, which is a puncture needle, is inserted into an outer needle, which is an indwelling needle. After the needle assembly is inserted into a blood vessel, the indwelling needle can be left in place by removing the inner needle. To prevent accidental punctures with the removed inner needle, a needle tip protector that houses the tip of the removed inner needle is commonly incorporated into the needle assembly.

[0003] For example, a needle tip protector has been considered that has a cylindrical case and a closing part that closes the tip of the case (see, for example, Patent Document 1). Because the pulled-out needle tip is stored in the case, it is possible to prevent accidental touching of the needle tip and splashing of blood adhering to the needle tip. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-93184 Summary of the Invention [Problem to be solved by the invention]

[0005] The needle tip protector is required to be held by the outer needle hub so as not to move with the movement of the inner needle until the needle tip is retracted, and to be able to smoothly detach along with the inner needle after the needle tip is retracted. Therefore, some kind of engagement mechanism is required to hold the needle tip protector stationary at the base end of the outer needle hub and release the hold when the needle tip is retracted. For example, in Patent Document 1, a locking claw that engages with the outer surface of the outer needle hub is provided as the engagement mechanism. When the inner needle is retracted into the needle tip protector and the closure is activated, the locking claw that was engaged with the outer surface of the outer needle hub moves outward and disengages from the outer needle hub. However, with such a configuration, it is necessary to ensure space outside the outer needle hub to allow the locking claw to move. This raises the risk that the locking claw may come into contact with the operator's fingers or the patient's skin, preventing the locking claw from moving outward.

[0006] An engagement mechanism that engages with the inside of the outer needle hub is also possible, but when complying with the ISO standards established for medical device connectors, there is little design freedom and it is difficult to ensure operational stability.

[0007] An object of the present disclosure is to realize a needle assembly that has high operational stability when disengaging a needle tip protector. [Means for solving the problem]

[0008] One aspect of the needle assembly of the present disclosure comprises an outer needle unit having an outer needle and an outer needle hub provided at the proximal end of the outer needle and having a connecting portion at the proximal end; an inner needle unit having an inner needle inserted into the outer needle and an inner needle hub provided at the proximal end of the inner needle; a connector cap removably attached to the connecting portion of the outer needle; and a needle tip protector that is held by the connector cap, contains the needle tip of the inner needle that has been removed from the outer needle, and is detached from the connector cap together with the inner needle unit, and the needle tip protector comprises a cylindrical case into which the inner needle is inserted through a distal needle hole and a proximal needle hole, and a needle tip protector attached toward the inserted inner needle. The needle is placed in the case in a biased state, and when the needle tip moves toward the base end from the distal needle hole, it moves radially inward relative to the distal needle hole to close the distal needle hole so that it cannot be opened; a guide slot that guides the relative movement of the closing part; and an engaging part whose position is restricted by the closing part and the restriction is released when the closing part moves relative to the base end, allowing the engaging part to be released from engagement with the connector cap.The engaging part has an engaging protrusion that protrudes radially outward and is movable from an engaging position where it engages with the inner surface of the connector cap to a releasing position radially inward from the engaging position where it is released from engagement with the inner surface of the connector cap.

[0009] In one aspect of the needle assembly, the needle tip protector is held by a connector cap removably attached to the proximal end of the outer needle hub, and the engaging portion has an engaging protrusion that can move to a release position radially inward from the engaging position, where it disengages from the inner surface of the connector cap. This prevents the engaging protrusion from hitting a finger or skin, preventing disengagement. The position of the engaging portion is restricted by the closing portion, and the relative movement of the closing portion releases the restriction, allowing the engaging portion to disengage from the connector cap. Furthermore, the relative movement of the closing portion is guided by a guide slot, reducing the risk of the closing portion performing an unintended movement and preventing the smooth release of the engaging portion, whose position is restricted by the closing portion. Therefore, the needle tip is firmly held in the connector cap until it is protected by the needle tip protector, and can be easily detached after protection is achieved. Thus, this needle assembly significantly improves operability and reliability.

[0010] In one aspect of the needle assembly, the engaging projection can be provided on a movable piece formed on the side wall of the case. This simplifies the configuration compared to arranging a member having the engaging projection on the side of the case, and this configuration makes it easy to realize an engaging projection that can move from the engaged position to the released position when the position restriction by the closing part is released.

[0011] In this case, the movable piece can be connected to the case by a thin hinge that is thinner than the other parts of the side wall surface. By adopting such a configuration, it is possible to smoothly move from the engaged position to the released position.

[0012] In one aspect of the needle assembly, the engaging portion has an abutment portion that abuts against the closing portion when it is positioned radially outward, and the abutment portion can be positioned outside the guide slot when the engaging protrusion is in the engaged position and inside the guide slot when the engaging protrusion is in the released position. This configuration makes it possible to easily move the closing portion while effectively utilizing space so that the engaging portion and the guide slot do not interfere with each other, thereby improving reliability and making the needle tip protector smaller.

[0013] In one aspect of the needle assembly, the engaging protrusion engages with an engaging hole formed in the connector cap in the engaged position, and at least one of the proximal surface of the engaging protrusion and the proximal surface of the engaging hole can be a sloped surface that tapers forward from the distal end to the proximal end. With this configuration, the engaging protrusion can be firmly engaged with the connector cap in the engaged position, and the engagement between the engaging protrusion and the engaging hole can be easily released after the position restriction by the closure part is released.

[0014] In one aspect of the needle assembly, the closing part can have a first magnetic body fixed to the case and a second magnetic body that moves while being guided by a guide slot and magnetically attaches to the first magnetic body when the needle tip moves from the distal needle hole toward the proximal end. This configuration eliminates the need to consider deterioration over time, and can provide a biasing force for closing the closing part without a complex mechanism, making the disengagement operation more stable. [Effects of the Invention]

[0015] According to the needle assembly of the present disclosure, the operational stability when disengaging the needle tip protector can be greatly improved. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a cross-sectional view of one embodiment of a needle assembly in a usable state. [Figure 2] 2 is an enlarged cross-sectional view showing the periphery of the needle tip protector of FIG. 1. FIG. [Figure 3] FIG. 10 is a cross-sectional view of one embodiment of a needle assembly in a protected state. [Figure 4] FIG. 4 is an enlarged cross-sectional view showing the periphery of the needle tip protector of FIG. 3. [Figure 5] FIG. 10 is a cross-sectional view of one embodiment of a needle assembly in a separated state. [Figure 6] FIG. 6 is an enlarged cross-sectional view showing the periphery of the needle tip protector of FIG. 5. [Figure 7] FIG. 4 is a cross-sectional view showing the inner surface of the tip portion of the needle tip protector. [Figure 8] FIG. 2 is a cross-sectional view showing a case main body of the needle tip protector. [Figure 9] FIG. 2 is a front view showing the case main body of the needle tip protector. DETAILED DESCRIPTION OF THE INVENTION

[0017] As shown in Figures 1 and 2, one embodiment of the needle assembly 100 comprises an outer needle unit 101 having an outer needle 111 and an outer needle hub 112 provided at the base end of the outer needle 111, an inner needle unit 102 having an inner needle 121 and an inner needle hub 122 provided at the base end of the inner needle 121, a connector cap 103 attached to the base end of the outer needle hub 112, and a needle tip protector 104 held by the connector cap 103.

[0018] The outer needle 111 is a hollow needle made of resin or the like. The inner needle 121 is a puncture needle made of metal or the like and has a sharp needle tip 123. The outer diameter of the inner needle 121 is approximately the same as the inner diameter of the outer needle 111, and the inner needle 121 is inserted through the outer needle 111.

[0019] The proximal end of the outer needle hub 112 forms a connection portion 171 to which a connector is connected. In this embodiment, the connection portion 171 is a female luer connector, and the assembly portion 151 is a male luer connector having a male luer portion 151a and a collar 151b. The assembly portion 151 is provided on the distal end side of the connector cap 103 and is removably assembled to the connection portion 171. The proximal end side of the connector cap 103 is provided with a holding portion 153 that holds the needle tip protector 104. In this embodiment, the inner needle hub 122 houses the proximal end of the holding portion 153 in a usable state.

[0020] 3 and 4, when the inner needle hub 122 is grasped and pulled toward the base end, the inner needle 121 is pulled out of the outer needle 111, and the needle tip 123 enters a protected state housed in the needle tip protector 104. As shown in Figures 5 and 6, when the inner needle hub 122 is pulled further toward the base end, the needle tip protector 104, which houses the needle tip 123, enters a separated state in which it is detached from the holding portion 153 of the connector cap 103.

[0021] The needle tip protector 104 has a cylindrical case 141, and a closing part 143 and a protector side engaging part 145 are housed inside the case 141. The case 141 has a tip side needle hole 161 and a base side needle hole 162, and in a usable state, the inner needle 121 extends through the base side needle hole 162 and the tip side needle hole 161.

[0022] The base end needle hole 162 is formed slightly smaller than the tip end needle hole 161. A stopper with a larger diameter than the rest of the inner needle 121 is formed proximally of the needle tip 123 of the inner needle 121. The stopper is formed so that it can pass through the tip end needle hole 161 but cannot pass through the base end needle hole 162. When the inner needle 121 is pulled out proximally, the stopper reaches the base end needle hole 162, and the inner needle 121 cannot move relative to the needle tip protector 104. The distance from the needle tip 123 to the stopper is shorter than the length of the case 141, so when the stopper reaches the base end needle hole 162, the needle tip 123 is located proximally of the tip end needle hole 161 and is housed within the case 141.

[0023] The closing part 143 is movable from an open position where it does not overlap with the tip-side needle hole 161 to a closed position where it blocks the tip-side needle hole 161. When the inner needle 121 is inserted through the tip-side needle hole 161, the movement of the closing part 143 to the closed position is restricted by the inner needle 121. In the present embodiment, the closing part 143 is a second magnetic body (movable magnetic body) made of a magnet or a hard magnetic body or the like and movably provided within the case, and when the inner needle 121 has passed through the tip-side needle hole 161, it is urged toward the inner needle 121 by a first magnetic body (fixed magnetic body) 147 made of a magnet or a hard magnetic body or the like that is fixed within the case 141 on the opposite side of the tip-side needle hole 161. As shown in Figures 3 and 4, when the needle tip 123 of the inner needle 121 moves proximally beyond the distal needle hole 161, it is no longer restricted by the inner needle 121, and the closing portion 143, which is a second magnetic body, slides radially inward toward the first magnetic body 147 and reaches a closed position where it closes the distal needle hole 161. At the closed position, the closing portion 143 is magnetically attached to the first magnetic body 147 and is fixed in the closed position so that the distal needle hole 161 will not be opened again. Note that although an example has been shown in which the entire closing portion 143 is made of a magnetic body, only a portion of the closing portion 143 may be made of a magnetic body. For example, a magnetic body can be fixed to a resin molded body by adhesive or the like, or the resin molded body and the magnetic body can be molded integrally by insert molding, or a soft magnetic body can be used as the magnetic body.

[0024] The protector-side engaging portion 145 has an engaging protrusion 181 that is movable from an engaging position where it engages with the inner surface of the connector cap 103 to a releasing position that is radially inward of the engaging position and where it is released from the engagement with the inner surface of the connector cap 103. At the engaging position, the engaging protrusion 181 is inserted into and engaged with a hole that is the cap-side engaging portion 155 formed in the holding portion 153 of the connector cap 103.

[0025] In this embodiment, the engaging protrusion 181 is provided at the tip of a movable piece 182 formed by cutting out a notch in the side wall surface of the case 141. In this embodiment, the tip side of the movable piece 182 is a free end, and the base end side is connected to the case 141, and the movable piece 182 can tilt radially inward with a connecting portion 183 as a fulcrum. When the inner needle 121 is inserted through the tip-side needle hole 161, as shown in FIG. 2 , the closure portion 143 is sandwiched between the tip of the movable piece 182 and the inner needle 121. Furthermore, the abutting portion 187 of the movable piece 182 abuts against or is close to the closure portion 143 and abuts when pressed inward, so that the tip of the movable piece 182 cannot substantially move radially inward. Therefore, the engaging protrusion 181 cannot disengage from the cap-side engaging portion 155.

[0026] As shown in Figure 4, when the needle tip of the inner needle 121 moves proximally beyond the distal needle hole 161 and is housed within the needle tip protector 104, the closing part 143 moves from the open position to the closed position, entering a protective state. This creates a gap between the movable piece 182 and the closing part 143, allowing the movable piece 182 to fall radially inward. When the needle tip protector 104 is pulled proximally in this state, as shown in Figure 6, the movable piece 182 falls radially inward so that the engaging protrusion 181 gets over the edge of the hole, which is the cap side engaging part 155, and the needle tip protector 104 can be pulled out of the holding part 153.

[0027] Since the displacement of the engaging protrusion 181 is restricted by the closing portion 143, it is possible to link the protection of the needle tip 123 with the release of the engagement between the needle tip protector 104 and the holding portion 153. This makes it possible to prevent the needle tip protector 104 from detaching from the holding portion 153 before the needle tip 123 is accommodated in the needle tip protector 104. Furthermore, once the needle tip 123 is accommodated in the needle tip protector 104 and protection is complete, the needle tip protector 104 can be detached from the holding portion 153 without applying a large force.

[0028] In this embodiment, a connection portion 183 between the case 141 and the base end of the movable piece 182 has a notch formed from the outer surface side to the inside or from the inner surface side to the outside, making it easy to collapse radially inward. In the embodiment shown in FIG. 2, a recess is formed on the outer surface of the connection portion 183, making the connection portion 183 a thin hinge that is thinner than other portions of the case 141, making it easy to collapse radially inward even with a small force. The movable piece 182 may also be configured so that the base end side is a free end and the connection portion is located on the tip side. The connection portion 183 may not have a notch or the like, so that the movable piece 182 can be configured to bend radially inward. Alternatively, the movable piece 182 may be configured so that it is rotatably connected to other portions of the case 141 via a pin.

[0029] The shape of the connecting portion 183 can also be such that the movable piece 182 is slightly biased radially inward. In this way, when the closing portion 143 moves to the closed position, the movable piece 182 automatically falls radially inward, so that the engaging protrusion 181 can be released from the cap-side engaging portion 155 with less force. Furthermore, even when the needle tip protector 104 is completely pulled out from the holding portion 153, the movable piece 182 remains slightly fallen radially inward, so that the engaging protrusion 181 does not protrude significantly outside the case 141, making it less likely that the engaging protrusion 181 will get caught when discarded. Note that the inwardly fallen engaging protrusion 181 may also be configured to engage with the inner surface of the case 141 and not return to the engaged position.

[0030] In this embodiment, the surface on the base end side of the engaging protrusion 181 and the surface on the base end side of the hole that is the cap-side engaging portion 155 are both vertical surfaces. At least one of the surface on the base end side of the engaging protrusion 181 and the surface on the base end side of the hole may be an inclined surface that tapers radially inward from the tip end side to the base end side. This makes it easier for the engaging protrusion 181 to climb over the edge of the hole.

[0031] In the example shown, the cap-side engaging portion 155 of the connector cap 103 with which the engaging protrusion 181 engages is a through-hole that penetrates the side surface of the connector cap 103, but it may also be a hole (recess) that does not penetrate through. If the cap-side engaging portion 155 is a through-hole, it is preferable that the tip of the engaging protrusion 181 inserted into the hole does not protrude from the outer surface of the connector cap 103, so that fingers or the like do not get caught. However, a protruding configuration is also possible. Furthermore, the protector-side engaging portion and the cap-side engaging portion are not limited to a protrusion and a hole into which the protrusion is inserted, and various configurations that allow them to releasably engage with each other can be adopted.

[0032] In the above embodiment, the engaging protrusion 181 is formed on the movable piece 182 and collapses inward to disengage from the cap-side engaging portion 155. However, various configurations that allow the engaging portion to move radially inward when the closing portion 143 moves to the closed position can be used as the engaging portion. For example, a sliding member inserted into a through-hole provided in the case 141 can be used as the engaging portion. When the closing portion 143 is in the open position, the sliding member is restricted from moving radially inward by the closing portion 143. When the closing portion 143 moves to the closed position, the sliding member is allowed to move radially inward. For example, the sliding member can have a large-diameter stopper at the base end to prevent it from falling out of the case 141, and an engaging protrusion protruding from the through-hole at the tip end. In this case, by forming the surface at the base end of the engaging protrusion into a forward-tapered inclined surface extending from the tip end to the base end, the sliding member can be released from the restriction and naturally slide radially inward when the case 141 is pulled toward the base end.

[0033] As shown in FIG. 7, in this embodiment, a guide slot 148 that facilitates sliding movement of the closing portion 143 is provided inside the case 141. In FIG. 7, the guide slot forming member 148a that forms the guide slot 148 has columnar members formed on both sides of the distal needle hole 161, and can restrict left-right movement of the closing portion 143. In addition, the guide slot forming member 148a has a wall member on the proximal end surface side of the closing portion 143 so that it can also restrict movement of the closing portion 143 toward the proximal end. Therefore, the closing portion 143 moves linearly from the open position to the closed position without significant wobble. Note that the restriction of movement of the closing portion 143 toward the proximal end can also be performed by a configuration other than the guide slot 148.

[0034] In this embodiment, the guide slot 148 is provided on the tip side of the case 141 and is a tunnel-shaped space that guides the movement of the closing part 143. As shown in Figures 2, 4, and 6, the movement of the closing part 143 in the width direction and the front-rear direction is restricted, and the closing part 143 moves while being guided in the sliding direction. The guide slot 148 can be formed by a guide slot forming member 148a molded integrally with the tip surface of the case 141, but it can also be formed by bonding a separate member, for example.

[0035] In this embodiment, case 141 is formed by a cylindrical case body 141a having an opening at the tip end, and a case cap 141b that closes the opening of case body 141a. Guide slot 148 is formed in case cap 141b. With this configuration, closure 143 can be assembled to the guide slot 148 portion of case cap 141b before it is attached to case body 141a, making manufacturing easier. Note that the guide slot may be formed in the case body, or in both the case body and the case cap.

[0036] In this embodiment, two slide ribs 149 are formed on the inner surface of the guide slot 148 along the sliding direction of the closing part 143. By providing the slide ribs 149, the contact area between the closing part 143 and the case cap 141b is reduced, allowing the closing part 143 to move more smoothly. However, a configuration without the slide ribs 149 is also possible.

[0037] 8 and 9, the movable piece 182 is formed by two slits 186 extending from the tip of the case main body 141a to the base end. It is adjusted so that a slight gap is formed between the tip of the movable piece 182 and the case cap 141b when the case cap 141b is attached. In addition, the engagement protrusion 181 provided at the tip of the movable piece 182 is formed so that the protruding height decreases toward the tip. By reducing the protruding height at the tip end of the engagement protrusion 181, it is possible to prevent the engagement protrusion 181 from getting caught on the inner surface of the case cap 141b when the engagement protrusion 181 falls radially inward.

[0038] In this embodiment, a rib 185 protruding radially inward is formed at the center of the width of the movable piece 182. When the closing part 143 is in the open position, the rib 185 abuts against the closing part 143 and functions as an abutment that limits the radially inward movement of the movable piece 182. If a guide slot 148 is provided to allow smooth movement of the closing part 143, interference may occur between the inner surface of the movable piece 182 and the guide slot forming member 148a, which includes the columnar member and wall member of the guide slot 148, when the movable piece 182 moves radially inward. For this reason, it is preferable to provide a notch or the like in the guide slot forming member 148a so that when the engaging protrusion 181 is in the engaged position, the radially inward protruding portion of the movable piece 182 is located outside the guide slot 148, and when the movable piece 182 falls radially inward and the engaging protrusion 181 is in the released position, the radially inward protruding portion of the movable piece 182 can enter the inside of the guide slot 148.

[0039] By limiting the portion that protrudes radially inward to only the narrow rib 185, even if no notch or a small notch is provided, when the engaging protrusion 181 is in the release position, the rib 185 is positioned inside the guide slot 148 and can be easily prevented from interfering. Also, by effectively utilizing the space around the engaging protrusion 181, the needle tip protector 104 can be prevented from becoming larger. Furthermore, by providing the rib 185, the strength of the movable piece 182 is increased, making it less likely that the movable piece 182 will break or bend significantly, causing the engagement between the engaging protrusion 181 and the cap side engaging portion 155 to be unintentionally released.

[0040] However, it is also possible to configure the movable piece 182 so that its entire width protrudes radially inward as an abutment portion without providing the rib 185. Even in this case, when the engaging projection 181 is in the release position, the portion of the abutment portion 187 that protrudes radially inward of the movable piece 182 and abuts against the closing portion 143 is positioned inside the guide slot 148, thereby preventing interference with the guide slot forming member 148a that forms the guide slot 148. In addition, by devising the configuration of the guide slot 148, it is possible to configure the guide slot 148 so that interference with the movable piece 182 is less likely to occur.

[0041] In this embodiment, the movable piece 182 is provided on the case main body 141a side, but the movable piece 182 can also be formed on the case cap 141b side. For example, a movable piece protruding from the case cap 141b toward the base end can be provided, a notch can be provided in the case main body 141a at a position corresponding to the movable piece, and an engagement protrusion can be provided near the base end of the movable piece.

[0042] 9, the tip of case body 141a is not a perfect circle but is a substantially elliptical shape with linear portions. This limits the direction in which case cap 141b can be attached to case body 141a, making it easier to align closing part 143 with movable piece 182. The shape of the tip is not limited to a two-fold rotationally symmetric shape such as an elliptical shape, and it can also be an asymmetric shape or a more symmetrical shape such as a perfect circle.

[0043] In this embodiment, case cap 141b is fixed to case main body 141a by a fixed snap fit in which hooks 165 formed on case main body 141a engage with holes 166 formed in case cap 141b. This configuration makes it possible to easily fix case cap 141b to case main body 141a. However, fixing case main body 141a and case cap 141b can be performed using various methods.

[0044] In this embodiment, the case 141 has a larger diameter at its distal end than at its proximal end. By making the distal end of the case 141 larger in diameter, it is possible to ensure space for incorporating the closing part 143 and the first magnetic body 147 and to prevent the overall size from increasing. From the viewpoint of ensuring space for incorporating the closing part 143 and the first magnetic body 147 and ensuring stable operation of the closing part 143, the inner diameter at the distal end is preferably at least about 3 to 4 times the outer diameter of the inner needle 121, and from the viewpoint of preventing the needle tip protector 104 from becoming larger, it is preferably no more than about 10 to 12 times.

[0045] In the present embodiment, the holding portion 153 of the connector cap 103 has an inner diameter that is approximately the same as the outer diameter of the needle tip protector 104. The holding portion 153 has a plurality of axially extending slits 156, which can be elastically deformed radially outward relatively easily. Therefore, after the needle tip protector 104 is assembled to the inner needle unit 102, the needle tip protector 104, with the engaging protrusion 181 protruding from the case 141, can be easily inserted into the holding portion 153 to engage the engaging protrusion 181 with the hole that is the cap-side engaging portion 155. This greatly improves manufacturing efficiency.

[0046] The holding portion 153 and the needle tip protector 104 may be provided with an indicator for alignment. For example, the holding portion 153 and the needle tip protector 104 may be provided with an indicator such as an arrow, and when the needle tip protector 104 is inserted into the holding portion 153 while aligning the arrow, the engaging protrusion 181 automatically engages with the cap side engaging portion 155. Various indicators that allow alignment may be used, not just arrows. Alignment is facilitated if an indicator is provided on at least one of the holding portion 153 and the needle tip protector 104. Furthermore, a guide may be provided as an indicator, allowing the needle tip protector 104 to be inserted into the holding portion 153 only in a specific position. For example, a notch and a protrusion may be provided, and when these are aligned, the needle tip protector 104 is inserted into the holding portion 153 and the engaging protrusion 181 automatically engages with the cap side engaging portion 155. Both an indicator and a guide may be provided.

[0047] The needle tip protector 104 can be engaged with the inner needle hub 122, and then the inner needle hub 122 can be placed over the outside of the holding part 153 while the needle tip protector 104 is inserted into the holding part 153. In this case, an indicator such as a mark or guide for engaging the needle tip protector 104 and the inner needle hub 122 in a predetermined positional relationship, and an indicator such as a mark or guide for engaging the inner needle hub 122 and the holding part 153 in a predetermined positional relationship can be provided. Also, a mechanism can be provided to prevent the needle tip protector 104 from rotating relative to the inner needle hub 122 when the needle tip protector 104 is engaged with the inner needle hub 122.

[0048] The inner surface of the connecting portion 171 provided at the base end of the outer needle hub 112 is smooth so as to achieve a liquid-tight connection with the connector on the tube side. Forming holes or recesses on the inner surface that engage with the engaging protrusions 181 while achieving liquid-tightness is not impossible, but requires high processing precision. Since the connector cap 103 is detached from the outer needle hub 112 when used as an indwelling needle, the shape of the inner surface is not limited, and through-holes or recesses that engage with the engaging protrusions 181 can be easily formed. Furthermore, unlike the outer needle hub 112, the holding portion 153 of the connector cap 103 can easily be formed with slits to enable elastic deformation radially outward. This makes it easy to hold the needle tip protector 104 with the engaging protrusions 181 protruding in the holding portion 153. The holding portion 153 can also be formed from a relatively flexible material to facilitate elastic deformation of the holding portion 153.

[0049] In this embodiment, the tip of the inner needle hub 122 houses the holding portion 153. This configuration reduces the possibility of the holding portion 153 and the needle tip protector being unintentionally disengaged. The inner needle hub 122 can also cover the through-hole that is the cap side engaging portion 155. In this way, the protector side engaging portion 145 and the cap side engaging portion 155 can be hidden, preventing the user from attempting to forcibly disengage the engagement.

[0050] In this embodiment, the assembly part 151 on the tip side of the connector cap 103 is a male luer connector having a male luer part 151a and a collar 151b, but it can have various configurations that allow it to be detachably connected to the connection part 171. In this embodiment, the male luer part 151a is formed thin so as not to press the plunger 176 provided on the outer needle hub 112.

[0051] In this embodiment, the outer needle hub 112 has a connecting portion 171 provided on the base end side, an outer needle fixing portion 174 provided on the tip end side for fixing the outer needle 111, and a flexible tube 173 connecting between the connecting portion 171 and the outer needle fixing portion 174.

[0052] In this embodiment, the base end of connection portion 171 is a female luer connector to which a male luer connector can be connected. A valve body 175 and a plunger 176 for opening valve body 175 are housed at the tip end of connection portion 171. When connector cap 103 is removed and a male connector is connected to connection portion 171, the plunger 176 is pushed toward the tip end by the male connector, opening valve body 175. When the male connector is pulled out, plunger 176 can be configured to move toward the base end to close valve body 175 again, or to remain at the tip end even when the male connector is pulled out, maintaining valve body 175 in an open state. Valve body 175 can be a slit valve.

[0053] The flexible tube 173 that connects the connecting part 171 and the outer needle fixing part 174 is made of soft resin. By providing the flexible tube 173, it is possible to prevent the movement of the connecting part 171 from being directly transmitted to the outer needle, facilitating the operation of connecting and disconnecting the connector to the connecting part 171. However, it is also possible to have a configuration in which the connecting part 171 and the outer needle fixing part 174 are integrated without providing the flexible tube 173.

[0054] The outer needle 111 can be formed into a hollow needle shape with appropriate flexibility. For example, the outer needle 111 can be formed from various soft resins such as ethylene-tetrafluoroethylene copolymer (ETFE), polyurethane, polyetheramide, or polypropylene. Furthermore, one or more through-holes may be provided in the tip of the outer needle 111 as necessary to allow efficient circulation of fluid to the outer needle 111. The outer needle 111 can be fixed to the outer needle hub 112 by fitting, crimping, fusion, or bonding with an adhesive.

[0055] The inner needle 121 is a hollow needle and can be made of known materials such as stainless steel, aluminum, titanium, or alloys containing these. The needle tip 123 provided at the distal end of the inner needle 121 may be tapered so that the outer diameter gradually decreases toward the tip, allowing for easy insertion into a living body with minimal irritation.

[0056] The inner needle hub 122 provided at the rear end of the inner needle 121 has a substantially cylindrical base portion to which the rear end of the inner needle 121 is fixed in an embedded state, a substantially cylindrical cover portion that protrudes from the tip of the base portion and fits externally onto the outer wall of the holding portion 153, and a substantially cylindrical connector portion that protrudes from the rear end of the base portion. The inner needle 121 can be fixed to the inner needle hub 122 by fitting, crimping, fusion, bonding with an adhesive, or the like. The rear end of the inner needle 121 is exposed at the rear end of the base portion, and the lumen of the inner needle 121 communicates with the internal space of the connector portion. The inner needle hub 122 can be a resin molded product in which the base portion, cover portion, and connector portion are integrated. If the inner needle hub 122 is transparent or translucent so that the interior can be seen, it becomes possible to check for blood flashback.

[0057] The inner needle cap 105 can be detachably attached to the opening of the connector portion of the inner needle hub 122. The inner needle cap 105 can be a stepped cylindrical synthetic resin member with a step provided in the axially middle portion. A breathable filter can be provided at the opening on the small diameter side of the inner needle cap 105 to prevent blood leakage when the needle assembly 100 is inserted into a patient's blood vessel. The breathable filter may be a filter that allows gas to pass through but blocks liquid. For example, a sintered porous body, a hydrophobic nonwoven fabric, or other porous body can be used.

[0058] In the present embodiment, a configuration has been shown in which the closing part 143 is moved from the open position to the closed position by magnetic force. However, the closing part 143 can be moved from the open position to the closed position by various methods other than magnetic force, such as the biasing force of a spring. However, by also using magnetic force, it is possible to prevent a large biasing force from being applied from the closing part 143 to the inner needle 121 in the open position, and therefore the inner needle 121 can be smoothly pulled out.

[0059] Although an example has been shown in which the closing part 143 abuts against the inner needle 121 in the open position, the closing part 143 may also be configured not to abut against the inner needle 121 in the open position. For example, a cylindrical member can be provided between the inner needle 121 and the closing part 143, and the cylindrical member can be moved together with the inner needle 121 to prevent the closing part 143 from abutting against the inner needle 121. Such a configuration allows the inner needle 121 to be pulled out more smoothly. [Industrial Applicability]

[0060] The needle assembly of the present disclosure has high operational stability when disengaging the needle tip protector, and is useful in the medical field and the like. [Explanation of symbols]

[0061] 100 needle assembly 101 Outer needle unit 102 Inner needle unit 103 Connector cap 104 Needle Tip Protector 105 Inner needle cap 111 Outer needle 112 outer needle hub 121 Inner needle 122 Inner needle hub 123 Needle tip 141 cases 141a Case body 141b Case cap 143 Closure 145 Protector side engagement part 147 First Magnetic Material 148 Guide Slot 148a Guide slot forming member 149 Slide Rib 151 Assembly section 151a Male lure part 151b color 153 Holding part 155 Cap side engagement part 156 Slit 161 Distal needle hole 162 Proximal needle hole 165 Hook 166 Hole 171 Connection 173 Flexible Tube 174 Outer needle fixing part 175 Valve body 176 Pusher 181 Engagement protrusion 182 Movable piece 183 Connection 185 Ribs 186 Slit 187 Contact part

Claims

1. an outer needle unit including an outer needle and an outer needle hub provided on the proximal end side of the outer needle and having a connecting portion at the proximal end; an inner needle unit having an inner needle inserted through the outer needle and an inner needle hub provided at a proximal end of the inner needle; a connector cap removably attached to the connection portion of the outer needle; a needle tip protector that is held by the connector cap, that accommodates the needle tip of the inner needle that has been removed from the outer needle, and that is detached from the connector cap together with the inner needle unit, The needle tip protector has a cylindrical case into which the inner needle is inserted through a distal needle hole and a proximal needle hole, a closing part that is arranged in the case while being biased toward the inserted inner needle, and that moves radially inward relative to the inner needle when the needle tip moves proximal to the distal needle hole to close the distal needle hole so that it cannot be opened, a guide slot that guides the radially inward relative movement of the closing part, and an engaging part whose position is restricted by the closing part, and whose restriction is released when the closing part moves relative to the inner needle hole, thereby enabling disengagement from the connector cap. the engaging portion has an engaging protrusion that protrudes radially outward and is movable from an engaging position in which it engages with the inner surface of the connector cap to a releasing position that is radially inward from the engaging position in which it is released from engagement with the inner surface of the connector cap.

2. 2. The needle assembly according to claim 1, wherein the engaging projection is provided on a movable piece formed on a side wall surface of the case.

3. 3. The needle assembly according to claim 2, wherein the movable piece is connected to the case by a thin hinge that is thinner than the other portions of the side wall surface.

4. the engaging portion has an abutting portion that abuts against the closing portion when the closing portion is positioned radially outward, The needle assembly of claim 1 , wherein the abutment portion is located outside the guide slot when the engagement protrusion is in the engaged position, and is located within the guide slot when the engagement protrusion is in the released position.

5. The engagement projection engages with an engagement hole formed in the connector cap at the engagement position, 2. The needle assembly according to claim 1, wherein at least one of a surface on the base end side of said engaging projection and a surface on the base end side of said engaging hole is an inclined surface tapered in a forward direction from the tip end side to the base end side.

6. 2. The needle assembly according to claim 1, wherein the closing portion comprises a first magnetic body fixed to the case, and a second magnetic body that moves while being guided by the guide slot and magnetically attracts to the first magnetic body when the needle tip moves toward the base end from the distal needle hole.

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