indwelling needle

Abstract

To provide a technology that improves the accuracy of operation of a device when the indwelling needle is contained in the device.SOLUTION: An indwelling needle 51 includes: a hollow needle 52; a body 53 having a hollow portion capable of containing the needle; a hub 55 for supporting the needle and arranged in the inside of the body, and capable of moving in the hollow portion from a first position where the needle is protruded out of an opening of the body to a second position where the needle is contained in the body; a coil spring 59 for biasing the hub in a direction going from the first position to the second position; and an engaging mechanism for engaging the hub with the body in the first position and the second position. The engaging mechanism has: an engagement part 57 provided at the hub and extending in the direction apart from a central axis 60; a first engaged hole 58 provided at the side of the body and engaged with the engagement part in the first position; and a second engaging hole 61 engaged with the engagement part in the second position. A distance from the central axis to the second engaging hole is shorter than the distance from the central axis to the first engaging hole.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an indwelling needle that is inserted into a blood vessel and left indwelling, and particularly to an indwelling needle that has a safety mechanism. [Background technology]

[0002] BACKGROUND ART Indwelling needles used for intravenous drips, blood sampling, and the like have been developed (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent No. 5,779,679 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the case of the indwelling needle 1 shown in Patent Document 1, a force is constantly acting from the spring 15 to the needle holder 14 in the state shown in Fig. 1. Therefore, for example, when the needle holder 14 transitions from the state shown in Fig. 1 to the state shown in Fig. 2, a force constantly acts on the protrusion 40, bending it in a direction approaching the central axis of the needle 16. Therefore, it is thought that the extending portion where the U-shaped arm 38 extends from the main body of the needle holder 14 will undergo plastic deformation in a direction approaching the central axis.

[0005] If the extending portion undergoes plastic deformation in this manner, it is conceivable that when the state shown in FIG. 1 of Patent Document 1 transitions to the state shown in FIG. 2 of Patent Document 1 and the protrusion 40 enters the opening 48, the protrusion 40 will not fully return in a direction away from the central axis. This is likely to result in a reduced degree of engagement between the protrusion 40 and the opening 48. In such a case, the protrusion 40 will not be retained in the opening 48 as desired, and the needle 16 may fall out of the opening 23 of the body 12. As a result, it may be difficult to securely house the needle 16 in the body 12.

[0006] Therefore, an object of the present invention is to provide a technique for improving the accuracy of operation of a safety mechanism in an indwelling needle having a safety mechanism that houses the needle exposed from the tip. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the present invention employs the following configuration.

[0008] That is, an indwelling needle according to one aspect of the present invention comprises: a hollow needle; a storage section which is a substantially tubular member having a hollow section capable of storing the hollow needle; a movable member which supports the base end of the hollow needle and is disposed inside the storage section and is capable of moving the hollow section from a first position where the hollow needle protrudes from an opening of the hollow section at one end of the storage section to a second position where the hollow needle is stored in the hollow section of the storage section; a spring which biases the movable member in a direction from the first position to the second position; and an engaging mechanism which causes the movable member to engage with the storage section at the first position and the second position, wherein the engaging mechanism has an engaging section which is provided on the movable member and extends in a direction away from a central axis, a first engaged section which is provided on a side surface of the storage section and engages with the engaging section at the first position, and a second engaged section which engages with the engaging section at the second position, wherein the distance from the central axis to the second engaged section is shorter than the distance from the central axis to the first engaged section.

[0009] According to this configuration, the engaging portion is engaged with the second engaging portion while suppressing the load on the engaging portion at the first position. A sufficient amount of engagement can be ensured when engaging with the mating portion. Therefore, when the hollow needle moves from a first position where it protrudes from the opening of the hollow portion to a second position where it is housed in the hollow portion, the engaging portion can be more reliably engaged with the second engaged portion, improving the accuracy with which the hollow needle is housed in the housing portion.

[0010] In the indwelling needle according to the above aspect, the surface of the second engaged portion facing the base end surface of the engaging portion has a surface that extends in a direction approaching the central axis as it moves toward the tip of the hollow needle, and the base end surface of the engaging portion may engage with the second engaged portion at a second position.

[0011] This configuration further reduces the possibility of the engaging portion moving in the proximal direction beyond the second position.

[0012] In the indwelling needle according to the above-described aspect, the opposing surface of the first engaged portion or the second engaged portion that faces the base end surface of the engaging portion may have a convex portion extending toward the tip, and the engaging portion may have a concave portion on the base end surface of the engaging portion that corresponds to the convex portion.

[0013] With this configuration, the engaging portion is fixed by the concave and convex portions, so that in the first position, the engaging portion is prevented from being deformed toward the central axis by the spring pressure, and in the second position, the engaging portion is prevented from being deflected toward the central axis and disengaged from the second engaged portion.

[0014] In the indwelling needle according to the above aspect, the opposing surface that faces the base end surface of the engaging portion of the first engaged portion may extend in a direction approaching the central axis and toward the tip, and the base end surface of the engaging portion may engage with the opposing surface.

[0015] According to this configuration, the engaging portion is in surface contact with the first engaged portion, so that the spring pressure can be received by the surface, reducing damage such as deformation and breakage of the engaging portion due to constant spring pressure.

[0016] In the indwelling needle according to the above aspect, the distance between the inner wall of the storage section and the central axis between the first engageable portion and the second engageable portion may be at least partially longer than the distance between the first engageable portion and the central axis and may be longer than the distance between the second engageable portion and the central axis.

[0017] According to this configuration, it is possible to reduce the sliding resistance when the engaging portion moves in the accommodating portion.

[0018] In the indwelling needle according to the above aspect, the free end of the engaging portion may have a shape in which the tip side thereof protrudes in a direction away from the central axis.

[0019] According to this configuration, it is possible to reduce the resistance felt when the engaging portion slides inside the accommodating portion.

[0020] In the indwelling needle according to the above aspect, the distal end wall of the engagement portion may have a shape that protrudes more toward the distal end as it moves in a direction away from the central axis.

[0021] According to this configuration, when the engaging portion moves in a direction approaching the central axis, it is possible to make it less likely for the engaging portion to come into contact with the hollow needle and the axis of the moving member.

[0022] Furthermore, an indwelling needle according to one aspect of the present invention includes a hollow needle; a housing portion which is a substantially tubular member having a hollow portion capable of housing the hollow needle; a movable member which supports the base end of the hollow needle and is disposed inside the housing portion and is capable of moving the hollow portion from a first position where the hollow needle protrudes from an opening of the hollow portion at one end of the housing portion to a second position where the hollow needle is housed in the hollow portion of the housing portion; and a movable member which moves the movable member from the first position to the second position. a spring that biases the movable member in a direction toward a first position, and an engagement mechanism that engages the movable member with the storage portion at the first position and the second position, wherein the engagement mechanism has an engaging portion that is provided on the movable member and extends in a direction away from the central axis, a first engaged portion that is provided on a side surface of the storage portion and engages with the engaging portion at the first position, and a second engaged portion that engages with the engaging portion at the second position, and wherein a notch is provided in a side surface of the storage portion that is angled with the side surface on which the first engaged portion and the second engaged portion are provided, along the direction from the first position to the second position.

[0023] According to this configuration, the provision of the notch makes it easier for the wall surface that comes into contact with the moving member when the moving member moves in the storage section to bend in a direction away from the central axis. Therefore, the frictional resistance that the moving member experiences from the wall surface of the storage section when the moving member slides is reduced. Therefore, movement of the sliding section from the first position to the second position is smooth. Furthermore, the biasing force of the spring that biases the moving member in the movement direction can be reduced. Therefore, deformation of the engaging portion provided on the moving member that engages with the first engaged portion and second engaged portion of the storage section due to constant spring pressure is suppressed. As a result, it is possible to improve the reliability of operation of the safety mechanism in the indwelling needle.

[0024] In the indwelling needle according to the above aspect, in the storage section, at least a portion of the inner wall of the side surface with which the engaging portion abuts may have an inclined surface that inclines in a direction away from the central axis as it moves from the first position to the second position.

[0025] With this configuration, the inner wall of the housing portion expands smoothly, reducing the frictional resistance that the movable member experiences from the inner wall of the side surface of the housing portion when the movable member moves from the first position to the second position. Therefore, the sliding portion moves smoothly from the first position to the second position. Furthermore, when biasing the movable member in the direction of movement, the biasing force can be reduced.

[0026] In the indwelling needle according to the above aspect, the movable member may further have a guide portion that protrudes in a direction away from the central axis or is recessed in a direction toward the central axis, and the accommodating portion may further have a guided portion that engages with the guide portion.

[0027] According to this configuration, when the engaging portion disengages from the first engaged portion and moves to the second engaged portion, the moving member can move smoothly without rattling, and the engaging portion can be reliably guided to the second engaged portion.

[0028] In the indwelling needle according to the above aspect, the moving member may further have a rib that prevents the moving member from moving relative to the housing portion in a distal direction when in the first position.

[0029] According to this configuration, the moving member is prevented from moving relative to the accommodating portion in the distal direction from the first position without going through the engaging portion. [Effects of the Invention]

[0030] According to the present invention, it is possible to improve the accuracy of the operation of the device when the needle exposed from the tip of the indwelling needle is housed within the device. [Brief explanation of the drawings]

[0031] [Figure 1] 1 shows an example of an outline of an indwelling needle according to an embodiment. (A) shows a schematic front view and a side view of the indwelling needle. (B) is an example of a cross-sectional view taken along the arrows A-A in (A). [Figure 2] FIG. 2 shows a schematic example of an outline of the body. (A) shows an example of a perspective view of the body. (B) shows an example of a cross-sectional view of the body taken along the line A-A in FIG. 2(A). FIG. 2(C) shows an example of a cross-sectional view of the body taken along the line B-B in FIG. 2(A). [Figure 3] FIG. 3 shows an enlarged view of a portion near the engaging portion. [Figure 4] Figure 4 shows an overview of the ribs. Figure 4(A) shows a perspective view of the hub on which the ribs are provided. Figure 4(B) shows a top view of the hub on which the ribs are provided. Figure 4(C) shows a cross-sectional view of the hub on which the ribs are provided housed in the body. [Figure 5] Figure 5 shows an example of the procedure for releasing the initial state of the indwelling needle shown in Figure 1 and storing the needle in the body. (A) shows a front view of the indwelling needle. (B) shows a cross-sectional view of (A). [Figure 6]6 shows an example of an outline of the locked state. (A) shows a front view of the indwelling needle. (B) shows a cross-sectional view of (A). [Figure 7] 7 shows an example of an outline of an indwelling needle according to a modified example. (A) shows a front view and a side view of the indwelling needle. (B) shows a cross-sectional view along the arrow A-A in (A). DETAILED DESCRIPTION OF THE INVENTION

[0032] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes embodiments of the present invention. The embodiments described below are merely examples of the present invention, and the technical scope of the present invention is not limited to the following aspects.

[0033] <Equipment configuration> FIG. 1 shows an example of the configuration of an indwelling needle 51 according to an embodiment of the present invention. FIG. 1(A) is a front view and a side view of the indwelling needle 51. FIG. 1(B) is a cross-sectional view taken along the arrow A-A in FIG. 1(A). As shown in FIG. 1, the indwelling needle 51 includes a hollow needle 52, a body 53 that houses the needle 52, and a hub 55 that is disposed inside the body 53 and holds the base end of the needle 52. Herein, the body 53 is an example of a "housing portion" according to the present invention. The hub 55 is an example of a "moving member" according to the present invention. Hereinafter, the left side of the indwelling needle 51 in FIG. 1 will also be referred to as the tip side, and the right side as the rear end side. The up and down directions in FIG. 1(B) will also be referred to as the upper side and the lower side, respectively. The side perpendicular to the plane of the paper in FIG. 1 will also be referred to as the right side, and the side perpendicular to the plane of the paper will also be referred to as the left side. The state of the indwelling needle during use as shown in FIG. 1 will also be referred to as the initial state. Furthermore, the state in which the needle 52 is housed in the body 53 after the initial state of FIG. 5 (to be described later) is released will also be referred to as a locked state hereinafter.

[0034] FIG. 2 schematically illustrates an example of the outline of the body 53 forming the indwelling needle 51. FIG. 2(A) shows a perspective view of the body 53. FIG. 2(B) shows an example of a cross-sectional view of the body 53, taken along the arrows A-A in FIG. 2(A). FIG. 2(C) shows an example of a cross-sectional view of the body 53, taken along the arrows B-B in FIG. 2(A). As shown in FIG. 2, the body 53 is formed from a cylindrical tip portion 53A and a main portion 53B located proximal to the tip portion 53A and having a hollow portion communicating with the hollow portion of the tip portion 53A. The main portion 53B is a cylindrical portion having a cross section that is approximately rectangular with rounded corners when viewed axially. When the indwelling needle 51 is used, the body 53 is fixed to the patient's skin so that the lower portion of the body 53 in FIG. 2(C) comes into contact with the skin. By fixing the body 53 in this manner, the difference in level between the needle and the skin can be reduced when the body 53 is fixed to the skin, thereby reducing the adverse effects of the metal needle on blood vessels. Furthermore, as shown in FIG. 2(C), the flat underside of the body 53 contributes to stabilizing the body 53 when it is fixed to the skin. Furthermore, the curved (rounded) sides of the body 53 prevent damage to the skin. Furthermore, the body 53 has openings at both ends along the central axis 60. Of the openings at both ends, the tip-side opening 54 is sized to allow the needle 52 and the tip portion 55A of the hub 55 that holds the base end of the needle 52 to pass through.

[0035] In addition, the body 53 is in a state where the needle 52 protrudes from the opening 54, and the engagement portion of the hub 55 57 (described later) to hold the needle 52 still. The first engagement hole 58 is provided on the distal end side of the main body portion 53B, on the upper and lower surfaces with respect to the central axis 60. As shown in FIG. 2(B), a proximal end surface 70 forming the first engagement hole 58 extends toward the central axis 60 and toward the distal end of the body 53. The proximal end surface 70 is provided with a protrusion 72 extending toward the distal end of the body 53. The proximal end surface 70 is an example of a "first engaged portion" of the present invention, and the first engagement hole 58 includes the "first engaged portion" of the present invention. The portion facing the proximal end surface of the engaging portion may be formed by providing a protrusion, or the portion facing the proximal end surface of the engaging portion may be formed by providing a groove. The proximal end surface 70 is an example of a "facing surface of the first engaged portion facing the proximal end surface of the engaging portion" of the present invention.

[0036] The body 53 also has a second engagement hole 61 on the movement direction side of the first engagement hole 58. The base end surface 73 forming the second engagement hole 61 extends in the direction of the central axis 60 toward the tip of the body 53. The base end surface 73 may also be provided with a convex portion similar to the convex portion 72 provided on the base end surface 70. Here, the base end surface 73 is an example of a "second engaging portion" of the present invention, and the second engagement hole 61 includes a "second engaged portion" of the present invention. The base end surface 73 is also an example of a "surface of the second engaged portion facing the engaging portion base end surface" of the present invention.

[0037] More specifically, the second engagement holes 61 are provided on the rear end side of the main body portion 53B, on the upper and lower surfaces with respect to the direction of the central axis 60. The first engagement hole 58 and the second engagement hole 61 penetrate the upper and lower walls of the body 53. Furthermore, the first engagement hole 58 and the second engagement hole 61 are provided such that the distance X between the second engagement hole 61 and the central axis 60 is shorter than the distance Y between the first engagement hole 58 and the central axis 60.

[0038] The body 53 also has cutouts 65 formed along the movement direction between the first engagement holes 58 and the second engagement holes 61. As shown in Fig. 2(C), a total of four cutouts 65 are provided so as to be located on both sides (on the left and right surfaces of the body 53) of the two first engagement holes 58 and the two second engagement holes 61.

[0039] In this embodiment, the first engagement hole 58 and the second engagement hole 61 are provided so as to open in the vertical direction on an arc-shaped surface of the rounded rectangular outer shape of the main body 53B, while the notch 65 is provided on a surface that has an angle (angle around the central axis of the body 53) with the surface on which the first engagement hole 58 and the second engagement hole 61 are provided. More specifically, the notch 65 is provided on an arc-shaped surface that sandwiches the surface on which the first engagement hole 58 and the second engagement hole 61 are provided (open), and is closer to the portion having the linear outer shape. The notch 65 may be open so that its axis is perpendicular to the outer shape of the main body 53B, or may be open so that its axis is perpendicular to the normal to the first engagement hole 58 and the second engagement hole 61.

[0040] 2(A), the first engagement hole 58 and the second engagement hole 61 appear to be provided on different surfaces of the outer shape of the body 53, but they are both open in the vertical direction in FIG. 1 and are provided on the same surface. However, in the present invention, the surfaces on which the first engagement hole and the second engagement hole are provided do not have to be exactly the same surface, and if they are provided on slightly different surfaces, the surfaces on which the first engagement hole and the second engagement hole are provided refer to surfaces included in the area determined by these two surfaces.

[0041] Furthermore, body 53 is provided with a pressing arm 66 that branches off from the main body and presses engagement portion 57 in a direction approaching central axis 60 of body 53. Here, pressing arm 66 is an example of the "pressing member" of the present invention, and can be bent in a direction approaching central axis 60, with connecting portion 62 with body 53 as a fixed end. Furthermore, pressing arm 66 is provided at its tip with a pressing portion 64 that protrudes in a direction approaching central axis 60. Pressing portion 64 is displaced in a direction approaching central axis 60 as pressing arm 66 bends in a direction approaching central axis 60.

[0042] Furthermore, when the engaging portion 57 moves, it comes into contact with an inner surface 68 of the main body portion 53B of the body 53 (details will be described later), and an inclined surface 67 that inclines in a direction away from the central axis 60 as it moves in the direction of movement is formed in a partial region on the tip side of the inner surface 68. The distance between the central axis 60 and the inner surface 68 is longer than the distance between the base end wall of the first engaging hole 58 and the central axis 60 and the distance between the base end wall of the second engaging hole 61 and the central axis 60. Furthermore, the body 53 may be shaped so that the distance between the central axis 60 and a portion of the inner surface 68 is longer than the distance between the first engaging hole 58 and the central axis 60 and the distance between the second engaging hole 61 and the central axis 60.

[0043] On the other hand, as shown in FIG. 1 , hub 55 is a hollow member that extends in the movement direction and is open at both ends in that direction. Hub 55 is formed of a tip portion 55A located at the tip side and supporting needle 52, a main body portion 55B located rearward of tip portion 55A, and a rear end portion 55C located further rearward of main body portion 55B. Needle 52 is fixed to hub 55 with its base end inserted into the opening of tip portion 55A of hub 55. In other words, the hollow portion of hub 55 and the hollow portion of needle 52 are in communication. By connecting needle 52 and hub 55 in this manner, for example, by supplying a medicinal solution from rear end portion 55C of hub 55, the medicinal solution can be supplied into the patient's body via the hollow portions of hub 55 and needle 52.

[0044] The hub 55 also includes a flexible extension portion 56 that branches off from the main body portion 55B and extends toward the tip. The tip of the extension portion 56 is provided with an engagement portion 57 that protrudes away from the central axis 60 and is engageable with the first engagement hole 58 and the second engagement hole 61. The engagement portion 57 can be positioned farther away from the central axis 60 than the inner surface 68 of the body 53, and is engaged with the first engagement hole 58 and the second engagement hole 61. The position of the hub 55 when the engagement portion 57 is engaged with the first engagement hole 58 corresponds to the first position in this embodiment. The position of the hub 55 when the engagement portion 57 is engaged with the second engagement hole 61 corresponds to the second position.

[0045] FIG. 3 also illustrates a partially enlarged view of the vicinity of engagement portion 57 of main body portion 55B. As shown in FIG. 3, the free end of engagement portion 57 has a shape in which a distal end surface 74 thereof protrudes in a direction away from central axis 60. A recess 76 recessed toward the distal end is provided in a proximal end surface 75 of engagement portion 57. In the initial state, proximal end surface 75 engages in surface contact with a proximal end surface 70 of first engagement hole 58. During engagement, recess 76 engages with a protrusion 72 provided on proximal end surface 70. In the locked state, proximal end surface 75 engages in surface contact with a proximal end surface 73 of second engagement hole 61. Proximal end surface 75 is an example of the "engagement portion proximal end surface" of the present invention.

[0046] Furthermore, when the engaging portion 57 is pressed, for example, from a direction away from the central axis 60 to a direction toward the central axis 60, the extending portion 56 bends toward the central axis 60, with the connecting portion 63 with the main body of the hub 55 as the fixed end. This allows the engaging portion 57 to move toward the central axis 60 and release the engagement with the first engaging hole 58 and the second engaging hole 61.

[0047] The hub 55 also has a rib 69 on its main body 55B that protrudes in a direction away from the central axis 60. FIG. 4 shows an overview of the rib 69. FIG. 4(A) shows a perspective view of the hub 55 when placed so that the rib 69 protrudes upward. FIG. 4(B) shows a top view of the hub 55 when placed so that the rib 69 protrudes upward. FIG. 4(C) is a cross-sectional view of the hub 55 along the arrow XX in FIG. 4(B), showing the hub 55 housed in the body 53. As shown in FIG. 4, the rib 69 protrudes in a direction away from the central axis 60. The rib 69 is provided along the central axis 60. While the rib 69 is provided on the top surface of the hub, it can also be provided on the bottom surface of the hub. Meanwhile, a groove 79 that guides the rib 69 is formed on the inner surface of the main body 53B of the body 53. The rib 69 and the groove 79 abut against each other. At the tip of the groove 79, a tip end is provided perpendicular to the direction of movement. The hub 55 is provided with a wall 80. The tip of the rib 69 abuts against the tip wall 80. Therefore, when the hub 55 moves in the movement direction, the hub 55 is guided by the groove 79 and the rib 69 formed on the inner surface of the main body portion 53B of the body 53. This ensures that the engaging portion 57 is guided into the second engaging hole 61. Furthermore, because the tip of the rib 69 abuts against the tip wall 80, relative movement of the hub 55 relative to the body 53 is prevented from moving distally from the initial state. Note that the tip wall 80 may be located a predetermined distance distally from the tip position of the rib 69 in the initial state. In such a structure, the hub 55 is allowed to move distally relative to the body 53 from the initial state, but it is preferable that the tip surface 74 of the engaging portion 57 does not or is unlikely to abut against the body. This prevents the engaging portion 57 from abutting against the body, resulting in deformation or damage. Here, the rib 69 is an example of a "guide portion" in the present invention. 4(C) may have holes formed therein that penetrate in a direction approaching the central axis 60, instead of the grooves 79. Alternatively, grooves may be formed on the outer surface of the hub 55, and protrusions may be formed on the inner surface of the body 53.

[0048] Furthermore, the indwelling needle 51 is provided with a coil spring 59 that biases the hub 55 in the movement direction. That is, the engaging portion 57 is biased in the movement direction by the coil spring 59.

[0049] <Explanation of accommodation flow> Next, the process by which needle 52 of indwelling needle 51 is housed in body 53 will be described. Figure 5 shows an example of the procedure for releasing the initial state of indwelling needle 51 shown in Figure 1 and housed needle 52 in body 53 to transition to a locked state. Figure 5(A) shows an example of a front view and a side view of indwelling needle 51. Figure 5(B) shows a cross-sectional view of Figure 5(A).

[0050] As shown in FIG. 5 , first, when a user applies force to pressing arm 66 in a direction toward central axis 60, pressing arm 66 bends, and pressing portion 64 and engagement portion 57 come into contact. Then, engagement portion 57 is pressed by pressing portion 64 in the direction toward central axis 60. At this time, recess 76 of engagement portion 57 and protrusion 72 of body 53 are engaged. Therefore, unless a force greater than a predetermined value acts on engagement portion 57 in the direction toward central axis 60, protrusion 72 will not disengage from recess 76. When a force greater than a predetermined value acts on engagement portion 57 in the direction toward central axis 60, protrusion 72 disengages from recess 76, and extension portion 56 bends in the direction toward central axis 60, with coupling portion 63 as a fixed end. Then, the entire engagement portion 57 disengages from first engagement hole 58. Here, when engaging portion 57 disengages from first engaging hole 58, tip surface 74 of engaging portion 57 has an inclined surface that slopes toward the tip as it moves in a direction away from central axis 60, and therefore contact with main body portion 55B of hub 55 is suppressed. Furthermore, because hub 55 is biased in the movement direction by coil spring 59, when engaging portion 57 disengages from first engaging hole 58, hub 55 moves from the tip side toward the rear end side. At that time, an elastic force acts on engaging portion 57, restoring it in a direction away from central axis 60, and therefore engaging portion 57 moves in the movement direction while abutting against the inner surface of body 53.

[0051] When the engaging portion 57 moves in the movement direction while abutting against the inner surface of the body 53, the engaging portion 57 first slides on the inclined surface 67 of the body 53. As shown in FIG. 2(B) , the inclined surface 67 is inclined away from the central axis 60 as it moves in the movement direction. Therefore, as the engaging portion 57 slides on the inclined surface 67, the frictional force applied to the engaging portion 57 by the inclined surface 67 gradually decreases. The engaging portion 57 then moves while abutting against an inner surface 68 (see FIGS. 2(B) and 2(C) ) located rearward of the inclined surface 67, and reaches the second engaging hole 61. When the engaging portion 57 reaches the second engaging hole 61, the restoring force of the bent extension portion 56 causes the engaging portion 57 to fit into the second engaging hole 61, thereby locking the engaging portion 57 into the second engaging hole 61.

[0052] Furthermore, the indwelling needle 51 has a notch 65 provided along the movement direction on a surface sandwiching the surface of the main body portion 53B where the first engagement hole 58 and the second engagement hole 61 are provided. When the engagement portion 57 slides on an inner surface 68 including the inclined surface 67 of the body 53, the inner surface 68 including the inclined surface 67 bends so as to bulge in a direction away from the central axis 60 (arrow in FIG. 5(B)). This also reduces the frictional force applied to the engagement portion 57 from the inner surface 68 when the engagement portion 57 slides on the inner surface 68. Note that the notch 65 is provided at a position sufficiently close to the first engagement hole 58 and the second engagement hole 61 so that the inner surface 68 can be easily bent when the engagement portion 57 slides on the inner surface 68 including the inclined surface 67 of the body 53.

[0053] Fig. 6 shows an example of an outline of the locked state. Fig. 6(A) shows a front view and a side view of indwelling needle 51. Fig. 6(B) shows a cross-sectional view of Fig. 6(A). As shown in Fig. 6, in the locked state, needle 52 is housed inside body 53.

[0054] Here, even in the locked state, the hub 55 is biased in the movement direction by the coil spring 59. However, the second engagement hole 61 is provided such that the distance X between the second engagement hole 61 and the central axis 60 is shorter than the distance Y between the first engagement hole 58 and the central axis 60. This increases the degree of engagement between the engagement portion 57 and the second engagement hole 61, making it possible to prevent the engagement portion 57 from disengaging from the second engagement hole 61 in the locked state.

[0055] [Actions and Effects] In the indwelling needle 51 described above, the extension portion 56 provided on the hub 55 bends toward the central axis 60, causing the engagement portion 57 to disengage from the first engagement hole 58. The hub 55 then moves in the movement direction due to the biasing force of the coil spring 59 in the movement direction. The disengaged engagement portion 57 moves while abutting against the inner surface 68 of the body 53, reaches the second engagement hole 61, and engages with the second engagement hole 61. Here, the distance X between the second engagement hole 61 and the central axis 60 is shorter than the distance Y between the first engagement hole 58 and the central axis 60. Therefore, in the first position, the extension portion 56 is in a natural state or is slightly bent toward the central axis 60 due to the pressure of the coil spring 59. Meanwhile, in the second position, the extension portion 56 is more bent toward the central axis 60 than in the first position. In other words, in the first position, the extension portion 56 is not excessively bent, and the load on the engagement portion 57 is suppressed. Therefore, the user does not need to press the engaging portion 57 excessively to disengage it from the first engaging hole 58, making it relatively easy to transition the needle 52 to the locked state. On the other hand, once the engaging portion 57 engages with the second engaging hole 61, a stronger restoring force acts on the engaging portion 57 in a direction away from the central axis 60 than when the engaging portion 57 engages with the first engaging hole 58. This prevents the engaging portion 57 from easily disengaging from the second engaging hole 61. This improves the reliability with which the needle 52 and hub 55 are accommodated in the body 53 when transitioning from the initial state to the locked state. Note that, in the second position, it is preferable that the engaging portion be accommodated within the second engaging hole 61. If the engaging portion extends outside the second engaging hole 61, the engaging portion can be pressed from outside, which is undesirable from a safety perspective.

[0056] Furthermore, with the indwelling needle 51 as described above, even if the engaging portion 57 or the extending portion 56 is plastically deformed in a direction approaching the central axis 60 due to the long-term biasing force exerted by the coil spring 59 in the initial state, the engagement between the engaging portion 57 and the second engaging hole 61 is large, so that the engaging portion 57 is prevented from coming off the second engaging hole 61. This improves the reliability with which the needle 52 and the hub 55 are housed in the body 53.

[0057] Furthermore, with the indwelling needle 51 as described above, the recess 76 of the engaging portion 57 and the protrusion 72 of the hub 55 are engaged in the initial state. Therefore, even if the user accidentally presses the engaging portion 57 in a direction approaching the central axis 60 without intending to insert the needle 52 into the body 53, Engagement portion 57 is prevented from coming off first engagement hole 58. In addition, engagement between recess 76 and protrusion 72 prevents engagement portion 57 from being deformed in a direction approaching central axis 60 due to the spring pressure of coil spring 59.

[0058] Furthermore, according to the indwelling needle 51 as described above, when the engaging portion 57 is engaged with the first engaging hole 58 in the initial state, the base end surface 70 of the first engaging hole 58 is in surface contact with the base end surface 75 of the body 53. Therefore, the biasing force of the coil spring 59 can be received by the base end surface 75, and damage such as breakage of the engaging portion 57 due to the constant pressure of the coil spring 59 is reduced.

[0059] Furthermore, according to the indwelling needle 51 as described above, the notch 65 is provided along the movement direction on a surface sandwiching the surface on which the first engagement hole 58 and the second engagement hole 61 are provided. Therefore, when the hub 55 slides on the inner surface 68 of the body 53, the inclined surface 67 or the inner surface 68 is likely to bend in a direction away from the central axis 60. Therefore, the frictional resistance that the engagement portion 57 of the hub 55 receives from the inclined surface 67 or the inner surface 68 of the body 53 is reduced.

[0060] Furthermore, the frictional resistance that the engaging portion 57 of the hub 55 receives from the inclined surface 67 or the inner surface 68 of the body 53 is reduced, which reduces the biasing force of the coil spring 59 and prevents the engaging portion 57 or the extending portion 56 from undergoing plastic deformation in a direction approaching the central axis 60. This also prevents the engaging portion 57, once engaged with the second engaging hole 61, from being released from the second engaging hole 61, improving the accuracy with which the needle 52 and the hub 55 are housed in the body 53.

[0061] Furthermore, the distance between the central axis 60 and the inner surface 68 is longer than the distance between the first engagement hole 58 and the central axis 60 and the distance between the second engagement hole 61 and the central axis 60. Therefore, the engagement portion 57 initially bends toward the central axis 60 when it disengages from the first engagement hole 58, but the amount of bending is reduced when it is in contact with the inner surface 68. In other words, the degree to which the urging force acting on the engagement portion 57 in the direction away from the central axis 60 is reduced. This also reduces the frictional resistance acting from the inner surface 68 to the engagement portion 57 when the engagement portion 57 moves in the movement direction.

[0062] Furthermore, because the engaging portion 57 is a free end, when the hub 55 moves in the movement direction inside the body 53, the engaging portion 57 moves smoothly along the inner surface 68. This prevents the engaging portion 57 from rattling, thereby reducing the distance required to move the needle 52 and the hub 55. Furthermore, the distal end surface 74 of the engaging portion 57 has a shape that protrudes in a direction away from the central axis. Therefore, as shown in FIG. 6 , in the locked state, the engaging portion 57 and the distal end wall 78 of the second engagement hole 61 face each other. Therefore, even if a force acting to move the hub 55 in the distal direction acts on the hub 55 in the locked state, the hub 55 comes into contact with the distal end wall 78, thereby preventing the hub 55 from moving in the distal direction.

[0063] Furthermore, according to the indwelling needle 51 described above, the base end surface 73 forming the second engagement hole 61 extends in a direction approaching the central axis 60 and toward the distal end of the body 53. This prevents the engagement portion 57 from disengaging from the second engagement hole 61 in the locked state. This prevents the needle 52 and hub 55 from moving in the proximal direction and falling out of the opening of the body 53 provided in the proximal direction.

[0064] Furthermore, in the above embodiment, the tip portion 53A of the body 53 has a cylindrical shape, and the main portion 53B is a tubular member having a vertically long, rounded rectangular cross section, but the shape of the body 53 is not limited to this. The body 53 may have any shape as long as the tip portion 53A and the main portion 53B have a hollow portion capable of accommodating the needle 52 and the hub 55, and may be, for example, a rectangular or elliptical shape with chamfered corners. The number of notches 65 is not limited. The position of the notches 65 may be determined based on the angle at which the hub 55 slides over the inclined surface 67 or 68 of the body 53 when the hub 55 slides over the inner surface 68 of the body 53. It is only necessary that the inner surface 68 bends in a direction away from the central axis 60 .

[0065] <Modification> FIG. 7 shows an overview of an indwelling needle 51A according to a modified example. FIG. 7(A) is a front view and a side view of the indwelling needle 51A. FIG. 7(B) is a cross-sectional view along the arrow A-A in FIG. 7(A). The hub 55 of the indwelling needle 51A does not have the rib 69 shown in FIG. 4. With this indwelling needle 51A, if the engaging portion 57 is unintentionally pushed toward the central axis 60, the engaging portion 57 may strike the distal wall of the first engaging hole 58 with force, potentially damaging the engaging portion 57. In this case, when the hub 55 is returned to its initial position by the coil spring 59, the protruding portion 72 may not engage with the recessed portion 76, potentially compromising the stability of the engaging portion 57 in its initial position. Therefore, in the indwelling needle 51A, a portion of the outer surface of the distal wall 81 of the first engaging hole 58 is cut out. With this indwelling needle 51A, the engaging portion 57 is prevented from coming into contact with the distal wall 81 of the first engaging hole 58 when the engaging portion 57 is pressed in a direction approaching the central axis 60. Therefore, even when the engaging portion 57 is moved from the initial position toward the distal end and then returned to the initial position, the engagement between the recessed portion 76 of the engaging portion 57 and the protruding portion 72 is stably performed. From the viewpoint of formability, the partial cutout on the outer surface of the distal wall 81 of the first engaging hole 58 may be tapered so that the outer surface tapers in a direction approaching the central axis toward the base end.

[0066] The embodiments and modifications disclosed above can be combined with each other. [Explanation of symbols]

[0067] 1··Indwelling needle; 2··Needle; 3··Body; 3B··Main body; 4··Opening; 5··Hub; 5A··Tip portion; 5B··Main body; 6··Extended portion; 7··Engagement portion; 8··First engagement hole; 9··Coil spring; 10··Central axis; 11··Second engagement hole; 14··Pressing portion; 15··Pressing arm; 16··Inner surface; 51··Indwelling needle; 52··Needle; 53··Body; 53A··Tip portion; 53B··Main body; 54··Opening; 55··Hub; 55A··Tip portion; 55B··Main body portion; 55C·· rear end portion; 56·· extension portion; 57·· engagement portion; 58·· first engagement hole; 59·· coil spring; 60·· central axis; 61·· second engagement hole; 62·· coupling portion; 63·· coupling portion; 64·· pressing portion; 65·· notch; 66·· pressing arm; 67·· inclined surface; 68·· inner surface; 69·· rib; 70·· base end surface; 72·· convex portion; 73·· base end surface; 74·· tip surface; 75·· base end surface; 76·· recess; 78·· tip wall; 79·· groove; tip wall 80; tip wall 81

Claims

1. A hollow needle, a housing portion that is a substantially cylindrical member having a hollow portion capable of housing the hollow needle; a moving member that supports the base end of the hollow needle and is disposed inside the housing portion, and that is capable of moving the hollow portion from a first position where the hollow needle protrudes from an opening of the hollow portion at one end of the housing portion to a second position where the hollow needle is housed in the hollow portion of the housing portion; a spring that biases the moving member in a direction from the first position toward the second position; an engagement mechanism that engages the moving member with the accommodation portion at the first position and the second position, The engagement mechanism includes: an engaging portion provided on the moving member, extending in a direction away from the central axis, and movable in the direction of the central axis when pressed; a first engaged portion provided on a side surface of the accommodation portion and engaging with the engaging portion at the first position; a second engaged portion that engages with the engaging portion at the second position, a distance from the central axis to the second engaged portion is shorter than a distance from the central axis to the first engaged portion; the engaging portion prevents the moving member from moving in a proximal direction at the first position and the second position; Indwelling needle.

2. a surface of the second engaged portion facing the base end surface of the engaging portion has a surface that extends in a direction approaching the central axis as it moves toward the distal end of the hollow needle, and the base end surface of the engaging portion engages with the second engaged portion at the second position; The indwelling needle according to claim 1.

3. a surface of the first engaged portion or the second engaged portion facing the base end surface of the engaging portion has a protrusion extending toward a distal end direction, The engaging portion has a recess corresponding to the protrusion on a base end surface of the engaging portion. The indwelling needle according to claim 2.

4. an opposing surface of the first engaged portion that faces the engaging portion base end surface extends toward the central axis and toward the tip end, and the engaging portion base end surface of the engaging portion engages with the opposing surface; The indwelling needle according to claim 2 or 3.

5. a distance between an inner wall of the accommodating portion and the central axis between the first engaged portion and the second engaged portion is at least partially longer than a distance between the first engaged portion and the central axis and a distance between the second engaged portion and the central axis; The indwelling needle according to any one of claims 1 to 4.

6. The free end of the engagement portion has a shape such that the tip side thereof protrudes in a direction away from the central axis. The indwelling needle according to any one of claims 1 to 5.

7. The distal end wall of the engagement portion has a shape that protrudes toward the distal end as it moves in a direction away from the central axis. The indwelling needle according to any one of claims 1 to 6.

8. a notch is provided in a side surface of the accommodation portion that is angled with a side surface on which the first engaged portion and the second engaged portion are provided, along a direction from the first position to the second position; The indwelling needle according to claim 1.

9. In the accommodation portion, at least a part of an inner wall of the side surface with which the engaging portion abuts has an inclined surface that inclines in a direction away from the central axis as it moves from the first position to the second position. The indwelling needle according to claim 8.

10. the moving member further includes a guide portion that protrudes in a direction away from the central axis or that is recessed in a direction toward the central axis, The accommodation portion further includes a guided portion that engages with the guide portion. The indwelling needle according to claim 8 or 9.

11. The moving member further includes a rib that prevents the moving member from moving relative to the accommodating portion in a distal direction when the moving member is at the first position. The indwelling needle according to claim 10.

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