Medical male connector

Abstract

To provide a medical connector having a new structure which can improve the reliability in connection between connectors through a coupler.SOLUTION: There is provided a medical male connector 10 in which a coupler 14 having a peripheral wall part 26 in which a female screw 28 for screwing to a female connector 42 is provided on the inner peripheral surface is attached to a plug 12 connected to the female connector 42 rotatably and movably in the axial direction. A flexible piece 30 which protrudes on the inner peripheral side of the peripheral wall part 26 is provided in the coupler 14. The plug 12 includes a fastening engagement surface 18 that is tilted in parallel with the central axis on the outer peripheral surface or in the direction of expanding the diameter toward the base end side. With the fastening of the coupler 14 to the female connector 42, the flexible piece 30 is brought into contact with a portion apart in the axial direction from the base end on the fastening engagement surface 18. A rotation angle of the coupler 14 at which the contact of the flexible piece 30 to the fastening engagement surface 18 is released is between 50° and 130°.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a medical male connector, and more particularly to a medical male connector having a coupler. [Background technology]

[0002] Conventionally, connections using luer connectors have been adopted in medical devices such as three-way stopcocks, syringes, catheters, and tubes. In addition, medical male connectors equipped with couplers have also been adopted for the purpose of improving the connection reliability of luer connectors. The medical male connector, such as the medical connector shown in JP 2017-148477 A (Patent Document 1), is equipped with a lock nut as a coupler that is rotatable and axially movable relative to the plug. The lock nut is screwed into the female connector connected to the plug, thereby connecting the plug and the female connector with high reliability. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-148477 A Summary of the Invention [Problem to be solved by the invention]

[0004] In order to ensure a secure connection by ensuring a good seal between the connectors, it is necessary that the medical male connector does not loosen in the release direction. Conventionally, attempts have been made to prevent relative rotation by making the initial torque required for relative rotation as large as possible, but it has recently been discovered that the application of unintended shocks or other factors can cause relative rotation, resulting in an incomplete seal or the risk of the connection between the connectors being released.

[0005] An object of the present invention is to provide a medical male connector having a novel structure that can improve the reliability of connections between connectors using couplers. [Means for solving the problem]

[0006] The following describes preferred embodiments for understanding the present invention, but the embodiments described below are merely illustrative and may be combined with one another as appropriate, and the multiple components described in each embodiment may be recognized and used independently as far as possible, and may also be combined with any of the components described in another embodiment as appropriate. As a result, the present invention is not limited to the embodiments described below, and various other embodiments may be realized.

[0007] The first aspect is a medical male connector in which a coupler having a peripheral wall portion with a female thread on its inner surface for screwing into the female connector is attached to a plug to be connected to the female connector so as to be rotatable and axially movable, the coupler is provided with a flexible piece protruding from the inner side of the peripheral wall portion, the plug has a fastening engagement surface on its outer surface that is parallel to the central axis or inclined in a direction expanding in diameter toward the base end, the flexible piece is positioned in abutment against a portion of the fastening engagement surface axially away from the base end by fastening the coupler to the female connector, the rotation angle of the coupler at which the flexible piece is released from abutment against the fastening engagement surface is 50° or more and 130° or less, starting from a connection state in which the coupler is positioned at the fastening end relative to the plug, and the abutment area between the flexible piece and the fastening engagement surface does not change until the abutment of the flexible piece against the fastening engagement surface is released.

[0008] In the medical male connector constructed according to this aspect, when the coupler is fastened to the female connector, the flexible piece abuts against the fastening engagement surface provided on the outer circumferential surface of the plug, and the frictional resistance acting between the flexible piece and the fastening engagement surface of the plug makes the coupler less likely to come loose due to unintentional rotation, thereby achieving a highly reliable connection between the plug and the female connector with a coupler that is less likely to come loose.

[0009] When the coupler is fastened to the female connector, the flexible piece is in contact with a portion of the fastening engagement surface that is axially distant from the base end, and therefore when the coupler loosens from the fastening to the female connector, the flexible piece moves while sliding against the fastening engagement surface of the plug. As a result, a resistance force due to friction between the flexible piece and the fastening engagement surface acts against the rotation of the coupler until the coupler moves sufficiently from the fastening end toward the base end, and therefore the coupler is prevented from loosening further in the event of unintended rotation of the coupler, which cannot cause the coupler to rotate at a large angle.

[0010] When the coupler rotates due to an unintended external force, the contact between the flexible piece and the fastening engagement surface is not released because the rotation angle of the coupler is small. Therefore, the resistance to the rotation of the coupler caused by the friction between the flexible piece and the fastening engagement surface is not released, and the rotation of the coupler is restricted, thereby preventing the coupler from loosening.

[0011] When a user such as a medical professional intentionally rotates the coupler to loosen it, the abutment between the flexible piece and the fastening engagement surface is released and the resistance to rotation of the coupler is released, even if the coupler is not rotated to an excessively large rotation angle, which makes it easy to loosen the coupler and release the connection between the connectors.

[0012] In a second aspect, a male connector for medical use is provided in which a coupler having a peripheral wall portion with a female thread on its inner surface for screwing into the female connector is rotatably and axially movable relative to a plug to be connected to the female connector, and the coupler is provided with a flexible piece protruding from the inner peripheral side of the peripheral wall portion, and the flexible piece is provided so as to be inclined toward the axial tip when not fastened to the female connector, while the inclination becomes gradually smaller as the coupler is fastened to the female connector, so that the flexible piece is inclined toward the axial tip when the coupler is fastened to the female connector. and the plug has a fastening engagement surface on its outer circumferential surface which is parallel to the central axis or inclined in a direction expanding in diameter toward the base end, and when the coupler is fastened to the female connector, the flexible piece is brought into contact with a portion of the fastening engagement surface which is axially spaced from the base end, and the rotation angle of the coupler at which the flexible piece is released from contact with the fastening engagement surface is between 50° and 130°, starting from a connection state in which the coupler is located at the fastening end relative to the plug. A third aspect is the medical male connector according to the first or second aspect, wherein the coupler is formed of a material harder than the plug.

[0013] The medical male connector constructed according to this aspect ensures the durability of the flexible piece provided on the coupler. Also, it is easier to set the elasticity of the flexible piece to be large, and it is possible to obtain a large resistance force due to friction between the flexible piece and the fastening engagement surface.

[0014] A fourth aspect is a medical male connector described in any one of the first to third aspects, wherein, when the flexible piece is in contact with the fastening engagement surface, the inner surface of the flexible piece that faces the fastening engagement surface has an inclined surface that inclines in a direction approaching the fastening engagement surface toward the tip of the flexible piece, and the axial length of the inclined surface satisfies either one of the following: more than twice the axial length of the abutting surface of the flexible piece against the fastening engagement surface, or more than 2 / 3 times the length from the base end of the contact surface to the base end of the flexible piece.

[0015] According to the medical male connector constructed in accordance with this aspect, the reaction force acting on the flexible piece due to the contact with the fastening engagement surface is easily dispersed and transmitted to the portion of the flexible piece having the inclined surface, thereby improving the load-bearing capacity, etc. Also, by providing the inclined surface over a sufficiently long area in the axial direction, the inclination angle of the inclined surface can be reduced while the contact surface is located close to the fastening engagement surface, so that the contact reaction force acting on the flexible piece due to the contact with the fastening engagement surface can be more effectively dispersed.

[0016] If the inclined surface makes the flexible piece thicker toward the abutment surface, the pressing force of the flexible piece against the fastening engagement surface based on the elasticity of the flexible piece can be adjusted. That is, by making the flexible piece thinner as it moves away from the abutment surface toward the base end side, it is possible to position the flexible piece in abutment against the fastening engagement surface, while also expecting to obtain a large pressing force against the fastening engagement surface based on the elasticity of the flexible piece, and the abutment force of the flexible piece against the fastening engagement surface can be stably exerted. In particular, by ensuring a long axial length of the inclined surface, it is possible to obtain a large degree of freedom in adjusting the elasticity of the flexible piece.

[0017] The fifth aspect is a medical male connector described in any one of the first to fourth aspects, wherein the rotational resistance characteristics during a removal operation to loosen the coupler from its fastened state to the plug include an initial resistance region in which the rotational resistance value of the coupler is mountain-shaped and peaks, and a continuous resistance region that continues over a rotation angle greater than the initial resistance region at an approximately constant rotational resistance value smaller than the peak of the initial resistance region.

[0018] According to the medical male connector constructed in accordance with this embodiment, the coupler is unlikely to come loose from the plug when the initial input is small because the rotational resistance of the coupler peaks in the initial resistance region. In addition, a substantially constant rotational resistance due to the contact between the fastening engagement surface and the flexible piece continues in the continuous resistance region, so that a substantially constant response can be obtained in the continuous resistance region when the coupler is removed. In addition, because the continuous resistance region continues over a rotation angle greater than the initial resistance region, the coupler does not immediately come off the plug even if, for example, an impact force is mistakenly applied, and the connection state between the coupler and the plug is maintained.

[0019] In a sixth aspect, in the medical male connector according to any one of the first to fifth aspects, the flexible piece is formed into an annular shape that continues in the circumferential direction of the coupler.

[0020] In the medical male connector constructed according to this embodiment, when the annular flexible piece is deformed toward the outside, a large shape restoring force based on the elasticity of the flexible piece is exerted, and the flexible piece is pressed strongly against the fastening engagement surface by the shape restoring force of the flexible piece. Therefore, a large resistance force against rotation of the coupler based on the frictional resistance acting between the flexible piece and the fastening engagement surface can be obtained, and unintended rotation of the coupler can be prevented.

[0021] In a seventh aspect, in the medical male connector according to the sixth aspect, the plug has the fastening engagement surface over its entire circumference, and the flexible piece is abutted against the fastening engagement surface over its entire circumference.

[0022] According to a medical male connector constructed in accordance with this embodiment, the contact area between the flexible piece and the fastening engagement surface can be made large in the circumferential direction, and large resistance force due to friction between the flexible piece and the fastening engagement surface can be obtained.

[0023] An eighth aspect is a medical male connector according to any one of the first to seventh aspects, wherein the plug has a large diameter portion protruding to the outer periphery, and the outer periphery of the large diameter portion is provided with the fastening engagement surface.

[0024] In a medical male connector constructed according to this embodiment, a fastening engagement surface is provided on the large diameter portion of the plug, making it easier to position the fastening engagement surface in a position that protrudes toward the flexible leaf, and making it easier to abut the flexible leaf and the fastening engagement surface.

[0025] A ninth aspect is a medical male connector according to any one of the first to eighth aspects, wherein the flexible piece has a protrusion that protrudes toward the inner circumference of the coupler, and the protrusion is abutted against the fastening engagement surface.

[0026] In a medical male connector constructed according to this aspect, the protrusion on the flexible piece protrudes toward the inner circumference, which is the fastening engagement surface side, making it easier to abut the flexible piece at the protrusion against the fastening engagement surface.

[0027] A tenth aspect is the medical male connector according to the ninth aspect, wherein the plug includes a locking portion that is locked with the protrusion in the axial direction.

[0028] With a medical male connector constructed according to this aspect, the locking portion of the plug and the protruding portion of the flexible piece are locked in the axial direction, so that the fastening end of the coupler relative to the female connector can be defined as the relative position of the coupler and the plug.

[0029] In an eleventh aspect, in a medical male connector described in any one of the first to tenth aspects, a guide inclined surface is provided at the contact portion between the flexible piece and the plug, which contact is made by axial movement of the coupler, to deform the flexible piece toward the outer periphery and guide it to ride up onto the fastening engagement surface.

[0030] In the medical male connector constructed according to this aspect, when the coupler is moved axially toward the tip side by fastening the coupler to the female connector, the plug and the flexible piece come into contact with each other on the guide inclined surface, so that the flexible piece is deformed toward the outer periphery and is guided so as to ride up onto the fastening engagement surface. Therefore, the flexible piece can move onto the fastening engagement surface without causing any inconvenience such as getting caught. Effect of the Invention

[0031] According to the present invention, in a medical male connector, even if an impact is applied to the coupler, causing unintended relative rotation, the rotational resistance force is not released and the rotation of the coupler is restricted, thereby preventing the coupler from loosening and improving the connection reliability between the connectors. [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 is a cross-sectional view showing a medical male connector according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view showing the medical male connector shown in FIG. 1 in a connected state with a female connector. [Diagram 3] A graph showing the measurement results of the rotation angle of a coupler in a medical male connector and the magnitude of the torque required for rotation. [Figure 4] FIG. 11 is an enlarged cross-sectional view showing a part of a medical male connector according to another embodiment of the present invention. [Diagram 5] FIG. 11 is an enlarged cross-sectional view showing a part of a medical male connector according to still another embodiment of the present invention. [Figure 6] FIG. 11 is an enlarged cross-sectional view showing a part of a medical male connector according to still another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0034] Fig. 1 shows a medical male connector 10 as a first embodiment of the present invention. The medical male connector 10 is a male luer connector having a structure in which a coupler 14 is disposed around a plug 12. In the following description, in principle, the axial direction refers to the left-right direction in Fig. 1, with the right side in Fig. 1 being the tip side and the left side in Fig. 1 being the base side.

[0035] The plug 12 has a generally cylindrical shape and extends in the axial direction from the base end to the tip end. The plug 12 has a luer taper in which the outer circumferential surface of the tip portion decreases in diameter from the base end to the tip end. The inner cavity of the plug 12 increases in diameter toward the tip, but may have a generally constant cross section in the axial direction, for example.

[0036] The plug 12 has a large diameter portion 16 in the axial middle portion. The large diameter portion 16 protrudes toward the outer periphery of the plug 12, and is provided partially in the axial direction of the plug 12. Since the large diameter portion 16 is provided so as to protrude partially, the outer diameter of the plug 12 is partially larger at the large diameter portion 16.

[0037] The large diameter portion 16 of the plug 12 has a plug-side engagement surface 18 as a fastening engagement surface on its outer circumferential surface. The plug-side engagement surface 18 is provided continuously around the entire outer circumferential surface of the large diameter portion 16, and is a cylindrical surface that is not inclined with respect to the axial direction of the plug 12 and extends substantially parallel to the axial direction of the plug 12. The plug-side engagement surface 18 is disposed in the axial middle portion of the large diameter portion 16, and the portion of the outer circumferential surface of the large diameter portion 16 closer to the base end than the plug-side engagement surface 18 is provided as a guide inclined surface 20 that becomes smaller in diameter toward the base end. The axial length dimension of the plug-side engagement surface 18 is larger than the axial width dimension of the tip surface of the thread of the female thread 28 of the coupler 14 described later.

[0038] The large diameter portion 16 is provided with a locking portion 22 that protrudes to the outer periphery. The locking portion 22 is annular and continuous around the entire circumference, and is disposed adjacent to the tip side of the plug side engagement surface 18. The locking portion 22 protrudes to the outer periphery beyond the plug side engagement surface 18, and the end face on the base end side is a first locking surface 24 that is an annular flat surface that expands perpendicular to the axial direction. The outer periphery of the locking portion 22 is a cylindrical surface extending approximately parallel to the axial direction at the base end adjacent to the first locking surface 24, and a tapered tubular surface with a smaller diameter toward the tip.

[0039] The coupler 14 has a cylindrical peripheral wall portion 26. A helical thread is formed on the inner peripheral surface of the peripheral wall portion 26, and a female thread 28 for screwing into a female connector 42 (described later) is provided. The base end of the coupler 14 is provided with a guide portion 29 that protrudes toward the inner circumference.

[0040] A flexible piece 30 is provided at the inner peripheral end of the guide portion 29 constituting the base end of the coupler 14, protruding from the base end side toward the tip side. The flexible piece 30 is generally cylindrical, and is provided continuously in the circumferential direction of the coupler 14 with a substantially constant cross-sectional shape. The tip surface of the flexible piece 30 is a tapered expanding surface 32 in which the inner peripheral portion is inclined toward the outer periphery toward the tip. The flexible piece 30 is disposed at a position spaced away from the inner periphery of the peripheral wall portion 26 of the coupler 14, and a space 34 provided between the flexible piece 30 and the peripheral wall portion 26 allows the flexible piece 30 to elastically deform toward the outer periphery. In this embodiment, the female screw 28 of the coupler 14 is formed up to the outer periphery of the flexible piece 30, and the threads of the female screw 28 protrude into the space 34, but for example, the female screw 28 may be provided on the tip side of the flexible piece 30 so that the threads of the female screw 28 do not protrude into the space 34. In the state shown in Figure 1, in which coupler 14 is not fastened to female connector 42 (described later), flexible piece 30 is inclined inward toward the tip, and cross-sectional center line L shown by a dotted line in Figure 1 is inclined with respect to the axial direction of coupler 14.

[0041] The flexible piece 30 has a protrusion 36 that protrudes toward the inner circumference. The protrusion 36 is provided in an annular shape over the entire circumference in a middle portion outside both axial ends of the flexible piece 30. Since the protrusion 36 is partially provided in the middle portion of the flexible piece 30, the inner diameter dimensions of both sides of the flexible piece 30 outside the protrusion 36 in the axial direction are made larger than the inner diameter dimension of the middle portion having the protrusion 36.

[0042] The inner peripheral surface of the protruding portion 36 is provided with a nut side engagement surface 38 as an abutment surface. The nut side engagement surface 38 is provided at the axial tip portion of the protruding portion 36. The nut side engagement surface 38 is provided continuously around the entire circumference of the protruding portion 36 and is a cylindrical surface extending parallel to the cross-sectional center line L of the flexible piece 30. Therefore, in the state shown in FIG. 1 in which the coupler 14 is not fastened to the female connector 42 described later, the nut side engagement surface 38 is a tapered cylindrical surface that inclines toward the inner circumference toward the tip side and has a small diameter. The length dimension of the nut side engagement surface 38 in the extension direction of the cross-sectional center line L is smaller than the axial length dimension of the plug side engagement surface 18 provided on the plug 12.

[0043] The inner peripheral surface of the protruding portion 36 is formed with a tapered cylindrical inclined surface 39 on the base end side of the nut side engagement surface 38. The inclined surface 39 extends at an angle with respect to the cross-sectional center line L in the longitudinal section shown in FIG. 1, has a smaller diameter toward the tip end side, and has a larger inclination angle with respect to the cross-sectional center line L than the nut side engagement surface 38. Since the outer peripheral surface of the flexible piece 30 is approximately parallel to the cross-sectional center line L, the flexible piece 30 gradually becomes thicker toward the tip end at the portion where the inclined surface 39 is formed. The length dimension of the protruding portion 36 in the extension direction of the cross-sectional center line L is larger than the axial length dimension of the thread of the female screw 28 of the coupler 14.

[0044] The end face on the tip side of the protrusion 36 is a second locking surface 40. The second locking surface 40 is an annular plane extending approximately perpendicular to the cross-sectional center line L. Therefore, the second locking surface 40 is a plane approximately perpendicular to the nut side engagement surface 38. The radial width dimension of the second locking surface 40 is preferably equal to or greater than the radial width dimension of the first locking surface 24 provided on the plug 12, and in this embodiment, it is greater than the radial width dimension of the first locking surface 24.

[0045] Both the plug 12 and the coupler 14 are made of resin. There are no particular limitations on the resin materials forming the plug 12 and the coupler 14, but the coupler 14 is preferably made of a material harder than the plug 12. Specifically, for example, the coupler 14 is made of polycarbonate, nylon, or the like, and the plug 12 is made of polypropylene, polyethylene, or the like. The plug 12 and the coupler 14 may be made of an opaque material, but are preferably made of a transparent or translucent material.

[0046] The coupler 14 is attached in an externally fitted state to the plug 12 and disposed so as to surround the plug 12. The coupler 14 is attached so as to be movable in the axial direction and rotatable in the circumferential direction relative to the plug 12. In this embodiment, a guide portion 29 provided on the coupler 14 is in sliding contact with the outer circumferential surface of the plug 12, thereby reducing rattling when the coupler 14 moves in the axial direction relative to the plug 12.

[0047] 1, when the coupler 14 is not fastened to a female connector 42 (described later), the flexible piece 30 of the coupler 14 is located at a position closer to the base end than the large diameter portion 16 of the plug 12. The nut side engagement surface 38 provided on the flexible piece 30 is located more inward than the plug side engagement surface 18 provided on the large diameter portion 16. The protrusion 36 of the flexible piece 30 is disposed at a position overlapping the guide inclined surface 20 of the large diameter portion 16 in the axial direction. The outer peripheral end of the locking portion 22 of the large diameter portion 16 is disposed at a position overlapping the expanding surface 32 of the flexible piece 30 in the axial direction.

[0048] In the medical male connector 10 having such a structure, the plug 12 is connected to the female connector 42, as shown in Fig. 2. The female connector 42 is made of resin, and the inner peripheral surface of the base end portion, which is substantially cylindrical, is provided with a luer taper that corresponds to the outer peripheral surface of the plug 12. A male thread 44 that protrudes to the outer periphery is formed at the base end of the female connector 42. The material from which the female connector 42 is made is not particularly limited, but is preferably a resin material softer than the coupler 14, for example, the same resin material as the plug 12.

[0049] Then, the female connector 42 is fitted onto the plug 12 from the tip side. Also, the coupler 14 moves toward the tip side relative to the plug 12, and the female threads 28 of the coupler 14 are tightened and screwed onto the male threads 44 of the female connector 42. As a result, the medical male connector 10 and the female connector 42 are connected liquid-tight, and a highly reliable connection is achieved by the coupler 14.

[0050] As the coupler 14 is fastened to the female connector 42, it moves toward the tip side relative to the plug 12. Then, the protrusion 36 of the flexible piece 30 provided on the coupler 14 abuts against the guide inclined surface 20 of the large diameter portion 16 provided on the plug 12. Since a force toward the outer periphery acts on the flexible piece 30 as a reaction force of the abutment against the guide inclined surface 20, the flexible piece 30 is pushed outward by the guide inclined surface 20 as the coupler 14 moves toward the tip side relative to the plug 12, and the flexible piece 30 is elastically deformed toward the outer periphery. As a result of the flexible piece 30 elastically deforming toward the outer periphery, in the connected state of the female connector 42 shown in FIG. 2, the cross-sectional center line L of the flexible piece 30 is approximately parallel to the axial direction of the coupler 14.

[0051] The locking portion 22 of the plug 12 is inserted into the tip portion of the flexible piece 30 pushed open by the guide inclined surface 20. The locking portion 22 abuts against the protrusion 36 provided on the flexible piece 30 in the axial direction. Then, the first locking surface 24, which is the base end surface of the locking portion 22, and the second locking surface 40, which is the tip surface of the protrusion 36, are locked in the axial direction, thereby restricting the movement of the coupler 14 toward the tip side relative to the plug 12. As a result, the coupler 14 is positioned at the fastening end, which is located when fastening to the female connector 42 is completed. The plug 12 and the female connector 42 are sandwiched in the axial direction between the second locking surface 40 of the coupler 14 and the threads of the female screw 28, and are connected in a liquid-tight sealed state by being urged toward each other in the axial direction.

[0052] When the coupler 14 is fastened to the female connector 42 and positioned at the fastening end, the flexible piece 30 of the coupler 14 overlaps the large diameter portion 16 of the plug 12 in the radial direction. More specifically, the protrusion 36 of the flexible piece 30, which is pushed open by contact with the guide inclined surface 20, moves along the guide inclined surface 20 and is guided so as to ride up onto the plug side engagement surface 18 provided continuously with the tip side of the guide inclined surface 20. The nut side engagement surface 38 of the protrusion 36 of the flexible piece 30 is overlapped in a state of abutment against the plug side engagement surface 18 of the large diameter portion 16 in the radial direction. Since the outer circumferential surface of the locking portion 22 is spaced from the inner circumferential surface of the flexible piece 30, the overlapping of the plug side engagement surface 18 and the nut side engagement surface 38 in the abutting state is reliably achieved without being hindered by the abutment between the outer circumferential surface of the locking portion 22 and the inner circumferential surface of the flexible piece 30.

[0053] When the coupler 14 is at the fastening end, the nut side engagement surface 38 is approximately parallel to the plug side engagement surface 18 due to the elastic deformation of the flexible piece 30, and the plug side engagement surface 18 and the nut side engagement surface 38 are overlapped in a surface contact state. The plug side engagement surface 18 and the nut side engagement surface 38 are pressed against each other by the elasticity of the flexible piece 30, and are overlapped in a frictionally engaged state engaged in the axial direction by frictional force. The plug side engagement surface 18 and the nut side engagement surface 38 are preferably in contact over the entire circumference, but it is sufficient that they are in contact at least partially in the circumferential direction. When the plug side engagement surface 18 and the nut side engagement surface 38 are in contact with each other, the inclined surface 39 of the coupler 14 is inclined inward toward the tip with respect to the axial direction parallel to the nut side engagement surface 38.

[0054] The nut side engagement surface 38 is positioned in contact with a portion of the plug side engagement surface 18 axially spaced from the base end, and in this embodiment, since it is overlapped with the tip portion of the plug side engagement surface 18, the plug side engagement surface 18 extends further toward the base end than the nut side engagement surface 38. However, the nut side engagement surface 38 may be positioned in contact with the base end of the plug side engagement surface 18 in addition to the portion of the plug side engagement surface 18 axially spaced from the base end. Also, the nut side engagement surface 38 may be positioned in contact with an intermediate portion of the plug side engagement surface 18 axially spaced from the base end and axially spaced from the tip.

[0055] When the coupler 14 is loosened from the female connector 42 and the coupler 14 moves from the fastening end to the base end with respect to the plug 12, the plug side engagement surface 18 provided on the plug 12 and the nut side engagement surface 38 provided on the coupler 14 slide against each other. A frictional resistance force acts between the plug side engagement surface 18 and the nut side engagement surface 38, which abut and frictionally engage with each other, during the sliding contact. As a result, a large force (torque) is required to rotate the coupler 14 to loosen it, making it difficult for unintended rotation of the coupler 14 to occur. Therefore, connection failures such as a decrease in the sealing property of the connection portion between the medical male connector 10 and the female connector 42 or a disconnection due to unintended loosening of the coupler 14 are avoided, and the intended connection state can be stably maintained.

[0056] Since both the plug side engagement surface 18 and the nut side engagement surface 38 extend to a certain length in the axial direction, a large frictional resistance force can be obtained due to sliding contact between the plug side engagement surface 18 and the nut side engagement surface 38. In addition, the frictional resistance force due to sliding contact between the plug side engagement surface 18 and the nut side engagement surface 38 is continuously exerted until the coupler 14 moves toward the base end side relative to the plug 12 by a predetermined amount or more. Therefore, the coupler 14 is less likely to loosen due to unintended rotation of the coupler 14.

[0057] In this embodiment, the rotation angle of the coupler 14 at which the plug-side engagement surface 18 of the plug 12 and the nut-side engagement surface 38 of the flexible piece 30 are released is set to a range of 50° to 130°. This prevents the frictional resistance caused by the abutment between the plug-side engagement surface 18 and the nut-side engagement surface 38 from being released by a slight rotation of the coupler 14 that may occur unintentionally, and prevents the coupler 14 from loosening. Furthermore, in an operation to intentionally loosen the coupler 14, the amount of rotation of the coupler 14 required to release the resistance to the rotation of the coupler 14 does not become too large, and the medical male connector 10 with excellent operability for disconnecting the connection with the female connector 42 can be realized. The rotation angle of the coupler 14 at which the plug-side engagement surface 18 and the nut-side engagement surface 38 are released is more preferably set to a range of 80° to 110°.

[0058] By rotating coupler 14 against the resistance force to a predetermined rotation angle set within the above-mentioned angle range, coupler 14 moves toward the base end side to a position where friction caused by the abutment between plug side engagement surface 18 and nut side engagement surface 38 with respect to plug 12 is released. Once the friction caused by the abutment between plug side engagement surface 18 and nut side engagement surface 38 is released, coupler 14 can thereafter be rotated with a small force.

[0059] In addition, the plug side engagement surface 18 is made longer in the axial direction than the nut side engagement surface 38, the nut side engagement surface 38 is located in contact with a portion of the plug side engagement surface 18 that is distant from the base end toward the tip end, and the plug side engagement surface 18 extends further toward the base end than the nut side engagement surface 38. As a result, even if the coupler 14 moves slightly toward the base end relative to the plug 12, the contact area between the plug side engagement surface 18 and the nut side engagement surface 38 does not change. Therefore, the resistance force due to the sliding contact between the plug side engagement surface 18 and the nut side engagement surface 38 is maintained, making it even more difficult for unintended rotation of the coupler 14 to occur that is large enough to cause loosening of the coupler 14.

[0060] It is desirable that the axial length of the plug-side engagement surface 18 is at least twice as long as the length of the nut-side engagement surface 38. According to this, when the coupler 14 is rotated, the entire nut-side engagement surface 38 abuts against the plug-side engagement surface 18 over at least half of the amount of rotation at which the plug-side engagement surface 18 and the nut-side engagement surface 38 are released from abutment, and the resistance force due to the sliding contact between the plug-side engagement surface 18 and the nut-side engagement surface 38 is made substantially constant. The axial length a of the plug-side engagement surface 18 is set to 50p / 360≦a≦130p / 360, where p is the thread pitch of the female thread 28 of the coupler 14.

[0061] In the state where the plug-side engagement surface 18 and the nut-side engagement surface 38 are in contact with each other, the axial length of the inclined surface 39 of the coupler 14 is set to be at least twice the axial length of the nut-side engagement surface 38. Also, the axial length of the inclined surface 39 of the coupler 14 is set to be at least 2 / 3 times the axial length from the base end of the nut-side engagement surface 38 to the base end of the flexible piece 30. This makes it easier for the reaction force acting on the flexible piece 30 by the abutment of the plug-side engagement surface 18 and the nut-side engagement surface 38 to be dispersed and transmitted to the base end side of the flexible piece 30 having the inclined surface 39, thereby improving the load resistance of the flexible piece 30. Also, by providing the inclined surface 39 over a long region in the axial direction, it is possible to ensure the protruding height of the protruding portion 36 and dispose the nut-side engagement surface 38 at a position protruding toward the inner periphery, while reducing the inclination angle of the inclined surface 39 with respect to the cross-sectional center line L. Therefore, the reaction force acting on the flexible piece 30 can be more effectively dispersed.

[0062] The flexible piece 30 has an inclined surface 39 on its inner peripheral surface, and an outer peripheral surface that is a cylindrical surface that is substantially parallel to the cross-sectional center line L, and the thickness of the inclined surface 39 gradually increases toward the nut-side engagement surface 38. Since the cross-sectional shape of the flexible piece 30 changes in the extension direction of the cross-sectional center line L in this manner, the pressing force of the nut-side engagement surface 38 against the plug-side engagement surface 18 based on the elasticity of the flexible piece 30 can be adjusted. In particular, since the length dimension of the inclined surface 39 is increased in the extension direction of the cross-sectional center line L, the elasticity of the flexible piece 30 can be adjusted with a large degree of freedom.

[0063] The plug-side engagement surface 18 and the nut-side engagement surface 38 are both cylindrical surfaces and are in contact with each other over the entire circumference, ensuring a large contact area in the circumferential direction. This makes it possible to obtain a large frictional resistance acting between the plug-side engagement surface 18 and the nut-side engagement surface 38, and to prevent unintended rotation of the coupler 14.

[0064] In this embodiment, since the flexible piece 30 is annular, the elastic deformation of the flexible piece 30 caused by the large diameter portion 16 of the plug 12 pressing against the inner peripheral surface of the flexible piece 30 causes the annular flexible piece 30 to deform in an enlarged diameter. Therefore, the elastic shape restoring force of the flexible piece 30 is large, and the nut side engagement surface 38 of the flexible piece 30 is pressed strongly against the plug side engagement surface 18 of the large diameter portion 16, so that the frictional resistance acting between the plug side engagement surface 18 and the nut side engagement surface 38 is large. Therefore, it is possible to set the torque required for rotation of the coupler 14 to be sufficiently large, and loosening due to unintended rotation of the coupler 14 is prevented.

[0065] The coupler 14 is made of a resin material harder than the plug 12. Therefore, the flexible piece 30 provided on the coupler 14 is also made of a hard resin material, improving the durability of the elastically deformable flexible piece 30. Furthermore, a large shape restoring force based on the elasticity of the flexible piece 30 can be obtained, making it possible to strongly press the nut side engagement surface 38 of the flexible piece 30 against the plug side engagement surface 18.

[0066] 3 is a graph showing the results (rotational resistance characteristics) of measurements of the rotation angle of the coupler and the torque required to rotate the coupler, in other words, the rotational resistance value of the coupler, in a removal operation for loosening the coupler from a fastened state (a state in which the coupler is at the fastening end relative to the plug) for a medical male connector (Example) constructed according to the present invention and a medical male connector (Comparative Example) constructed according to a conventional structure. In the graph of FIG. 3, the rotational resistance characteristics of the Example of the present invention are shown by a solid line, and the rotational resistance characteristics of the Comparative Example of the conventional structure are shown by a dashed line. The horizontal axis of the graph of FIG. 3 is the rotation angle of the coupler, and the unit of the rotation angle is "°". The vertical axis of the graph of FIG. 3 is the torque (rotational resistance value) required to rotate the coupler, and the unit of the torque is "N·cm".

[0067] According to the graph of FIG. 3, in a separation operation for loosening the coupler, the rotational resistance characteristic of the embodiment has an initial resistance region and a continuous resistance region.

[0068] The initial resistance region is a mountain-shaped region where the torque of the coupler relative to the rotation angle of the coupler peaks. More specifically, the initial resistance region is the region in the graph in Figure 3 where the coupler rotation angle exceeds 20° from 0°, and has a maximum torque peak (about 8.0 N cm) when the rotation angle reaches 20°.

[0069] The continuous resistance region is the region from when the torque decrease after the peak of the initial resistance region stops at about 3.0 N·cm until the rotation angle reaches approximately 100°, and since it shows a roughly constant torque that is smaller than the peak of the initial resistance region, the graph remains flat. The continuous resistance region is the region from when the coupler rotation angle exceeds 20° to around 100°, and continues for a larger rotation angle than the initial resistance region, which is the region from 0° to just over 20°.

[0070] The rotation angle of 0° on the horizontal axis of the graph in Fig. 3 is the connection state (see Fig. 2) in which the coupler 14 is located at the fastening end relative to the plug 12, and as the rotation angle increases, the coupler 14 moves toward the base end side relative to the plug 12 with a change in resistance from static friction (maximum static friction) to kinetic friction and its continuation. Therefore, from the graph in Fig. 3, resistance due to sliding contact between the nut side engagement surface 38 and the plug side engagement surface 18 of the flexible piece 30 is exerted over the entire initial resistance region and continuous resistance region, which are in the angle range of approximately 0° to 100°. In particular, it was confirmed that due to the rotation resistance characteristic in Fig. 3 having the initial resistance region and continuous resistance region, when rotating and loosening the coupler 14, after a relatively hard response at the beginning of rotation (0° to 20°), a substantially constant response can be obtained over a wide angle range of 20° to 100°.

[0071] In Figure 3, in the continuous resistance region, the torque increases to about 4.0 N·cm when the rotation angle of the coupler exceeds 45°, and is maintained at the increased torque until it approaches 100°. This is thought to be due to a change in the contact manner between the threads of the female screw of the coupler and the threads of the male screw of the female connector, and since this is different from the rotation resistance of the coupler caused by the contact between the flexible piece and the fastening engagement surface, the torque of the coupler can be considered to be approximately constant in the continuous resistance region. Note that, for example, by adjusting the shape, pitch, material, etc. of the threads of the female screw of the coupler and the male screw of the female connector, it is possible to reduce or avoid changes in torque in the continuous resistance region caused by changes in the contact manner of the threads.

[0072] On the other hand, in the comparative example, maximum torque (about 10.0 N·cm) is exerted when the rotation angle of the coupler reaches about 8°, after which the torque drops rapidly with further rotation. Then, when the rotation angle reaches about 30°, the torque becomes 0 and the coupler enters a state in which it can rotate freely without resistance. In short, the rotational resistance characteristics of the comparative example coupler form a mountain shape that peaks overall, and after the peak is exceeded, the torque drops rapidly.

[0073] In this way, the medical male connector of the embodiment of the present invention exerts a resistance against the rotation of the coupler until the rotation angle of the coupler becomes larger than that of the medical male connector of the comparative example of the conventional structure. In the medical male connector of the comparative example, the resistance against the rotation of the coupler is significantly reduced by a slight rotation of the coupler, so that even an unintended slight rotation of the coupler may reduce the resistance and the connection between the connectors by the coupler may not be maintained. In contrast, the medical male connector of the embodiment exerts a resistance against the rotation of the coupler until the rotation angle of the coupler approaches 100°, so that even if the coupler rotates slightly unintendedly, the resistance is maintained and the loosening of the coupler is prevented from progressing. Therefore, the medical male connector of the embodiment avoids the poor connection between the connectors due to the unintended loosening of the coupler, which is a problem in the comparative example, and a more reliable connection between the connectors can be realized.

[0074] The rotational resistance characteristics of the medical male connector shown in the graph of Fig. 3 are merely illustrative, and the magnitude of the torque and the angular ranges of the initial resistance region and the continuous resistance region can be changed as appropriate. For example, the magnitude of the torque exerted in the continuous resistance region can be adjusted by adjusting the frictional resistance force (normal force or friction coefficient) between the plug-side engagement surface 18 and the nut-side engagement surface 38 depending on the material and shape of the large diameter portion 16 of the plug 12 and the flexible piece 30 of the coupler 14, or the axial length of the plug-side engagement surface 18 can be adjusted to adjust the angular range of the continuous resistance region.

[0075] Although the embodiment of the present invention has been described above in detail, the present invention is not limited to the specific description. For example, in the above embodiment, the annular flexible piece 30 that is continuous around the entire circumference of the coupler 14 is exemplified, but the flexible piece is not limited to a continuous annular shape around the entire circumference. Specifically, for example, if the flexible piece is made to be a plate-like piece with a length that is less than one circumference in the circumferential direction, the elastic restoring force of the flexible piece is reduced compared to the annular flexible piece 30, so that the torque required to rotate the coupler 14 can be adjusted to be smaller. Note that a plurality of flexible pieces may be provided, and for example, a plurality of flexible pieces may be arranged in the circumferential direction.

[0076] In the above embodiment, the plug side engagement surface 18 and the nut side engagement surface 38 are each a cylindrical surface, but the plug side engagement surface and the nut side engagement surface are not limited to being cylindrical surfaces that are continuous over the entire circumference. However, it is preferable that at least one of the plug side engagement surface and the nut side engagement surface is a cylindrical surface that is continuous over the entire circumference, so that the contact area between the plug side engagement surface and the nut side engagement surface can be constant regardless of the circumferential orientation of the plug 12 and the coupler 14.

[0077] In the above embodiment, the plug side engagement surface 18 is longer in the axial direction than the nut side engagement surface 38, and the plug side engagement surface 18 extends further toward the base end than the nut side engagement surface 38, but the axial length of the plug side engagement surface may be the same as that of the nut side engagement surface, or may be shorter than that of the nut side engagement surface. When the axial length of the plug side engagement surface is shorter than that of the nut side engagement surface, it is preferable that the plug side engagement surface abuts against a portion of the nut side engagement surface that is axially distant from the tip end. This allows the frictional resistance between the plug side engagement surface and the nut side engagement surface to be maintained until the coupler moves more toward the axial base end relative to the plug, preventing unintended loosening of the coupler.

[0078] As shown in FIG. 4, the fastening engagement surface may be an inclined surface inclined toward the outer periphery toward the base end, as shown in FIG. 4, the plug side engagement surface 52 provided on the large diameter portion 50 as the fastening engagement surface. As shown in FIG. 4, the nut side engagement surface 58 provided on the protruding portion 56 of the flexible piece 54 as the abutting surface against the fastening engagement surface may be an inclined surface inclined toward the outer periphery toward the base end. In FIG. 4, the inclination angle of the plug side engagement surface 52 and the inclination angle of the nut side engagement surface 58 are substantially the same, and the plug side engagement surface 52 and the nut side engagement surface 58 are overlapped in a surface contact state. If the plug side engagement surface 52 and the nut side engagement surface 58 are inclined surfaces as described above, it may be possible to adjust the resistance force caused by the sliding contact between the plug side engagement surface 52 and the nut side engagement surface 58 by the inclination angle of the engagement surfaces 52, 58. When the plug side engagement surface 52 and the nut side engagement surface 58 are inclined surfaces as shown in Fig. 4, the inclination angle of the plug side engagement surface 52 with respect to the axial direction is preferably 20° or less so that the coupler can be easily fastened to and removed from the female connector. The inclination angle of the plug side engagement surface and the nut side engagement surface with respect to the axial direction may change gradually or in steps in the axial direction. In the explanation of Fig. 4 and Figs. 5 and 6 described later, the explanation of the members and parts that are substantially the same as those in other embodiments will be omitted by assigning the same reference numerals in the figures.

[0079] In the above embodiment, the flexible piece 30 of the coupler 14 has the nut-side engagement surface 38 that abuts against the plug-side engagement surface 18 of the plug 12, but the flexible piece does not necessarily have to be in surface contact with the plug-side engagement surface. Specifically, for example, the protruding portion 56 of the flexible piece 54 shown in FIG. 5 has an inner circumferential surface that is entirely inclined with respect to the plug-side engagement surface 18, and the flexible piece 54 abuts against the plug-side engagement surface 18 at the tip edge 60 of the inner circumferential surface of the protruding portion 56. In this manner, the flexible piece may be in line contact with the fastening engagement surface (plug-side engagement surface). Note that the abutment portion between the flexible piece and the fastening engagement surface does not have to extend in the circumferential direction, and the flexible piece may be in point contact with the fastening engagement surface.

[0080] The protrusion 36 provided on the flexible piece 30 in the above embodiment is not essential. Specifically, for example, a structure without a protrusion protruding toward the inner circumference, such as the flexible piece 70 shown in FIG. 6, may be adopted. In addition, in the structure of FIG. 6, a guide inclined surface is provided on the coupler 14 side. That is, the inner circumferential portion of the tip surface of the flexible piece 70 is formed as a guide inclined surface 72 that inclines toward the outer circumference and expands toward the tip. When the coupler 14 is fastened to the female connector (not shown), the flexible piece 70 before reaching the fastening end shown by the two-dot chain line in FIG. 6 abuts against the large diameter portion 74 protruding from the outer circumferential surface of the plug 12 at the guide inclined surface 72. Then, an abutment reaction force toward the outer circumference acts on the flexible piece 70, and the flexible piece 70 is pushed and expanded, and is guided onto the plug-side engagement surface 18, which is the outer circumferential surface of the large diameter portion 74. The flexible piece 70 guided onto the plug-side engagement surface 18 is pressed against the plug-side engagement surface 18 at the nut-side engagement surface 38 that constitutes the inner circumferential surface. As a result, in the structure shown in Fig. 6, a frictional resistance force acts between the plug-side engagement surface 18 and the nut-side engagement surface 38, which limits the relative rotation of the coupler 14 with respect to the plug 12, preventing the coupler 14 from loosening.

[0081] It is also possible to provide both the guide inclined surface 20 on the plug 12 side and the guide inclined surface 72 on the coupler 14 side, and for example, the guiding effect may be achieved by the guide inclined surfaces 20, 72 abutting against each other.

[0082] In the above embodiment, the first locking surface 24 and the second locking surface 40 are each formed as a continuous ring shape around the entire circumference, but the first locking surface and the second locking surface are not necessarily limited to being ring-shaped. The first locking surface and the second locking surface are not limited to being flat, and may be, for example, an inclined surface or a curved surface. Furthermore, the first locking surface and the second locking surface do not have to be perpendicular to the axial direction as long as they can abut against each other to position the coupler at the fastening end in the axial direction.

[0083] In the above embodiment, the fastening end of the coupler 14 is defined by engagement between the first locking surface 24 provided on the large diameter portion 16 having the plug side engagement surface 18 and the second locking surface 40 provided on the flexible piece 30 having the nut side engagement surface. However, the structure for defining the fastening end of the coupler may be provided separately from the portion having the plug side engagement surface and the nut side engagement surface. [Explanation of symbols]

[0084] 10 Medical Male Connector 12 Plug 14 Coupler 16 Large diameter section 18 Plug side engagement surface (fastening engagement surface) 20 Guide inclined surface 22 Locking part 24 First locking surface 26 Peripheral wall section 28 Female thread 29 Guide section 30 Flexible piece 32 Expanded surface 34 Space 36 Protrusion 38 Nut side engagement surface (contact surface) 39 Slope 40 Second locking surface 42 female connector 44 Male thread 50 Large diameter section 52 Plug side engagement surface (fastening engagement surface) 54 Flexible piece 56 Protrusion 58 Nut side engagement surface (contact surface) 60 Edge 70 Flexible piece 72 Guide inclined surface 74 Large diameter section

Claims

1. A medical male connector in which a coupler having a peripheral wall portion on an inner peripheral surface of which is provided with a female thread for screwing into a female connector is rotatably and axially movably attached to a plug to be connected to the female connector, the coupler is provided with a flexible piece protruding from an inner circumferential side of the peripheral wall portion, The plug has a fastening engagement surface on an outer circumferential surface thereof which is parallel to a central axis or which is inclined in a direction in which the diameter of the fastening engagement surface increases toward a base end side, A fastening end is defined by an axial engagement between a first engagement surface provided on the plug and a second engagement surface provided on the coupler, A medical male connector in which, when the coupler is tightened onto the female connector, the flexible piece is positioned in contact with a portion of the fastening engagement surface away from the base end in the axial direction, and the contact force does not increase and the contact area between the flexible piece and the fastening engagement surface does not change during the period from when the flexible piece moves from the fastening end in the contact release direction to when the contact force of the flexible piece against the outer peripheral surface of the plug begins to decrease.

2. A medical male connector in which a coupler having a peripheral wall portion on an inner peripheral surface of which is provided with a female thread for screwing into a female connector is rotatably and axially movably attached to a plug to be connected to the female connector, The plug has an outer circumferential surface provided with a fastening engagement surface and a guide surface, the coupler is provided with a flexible piece protruding from an inner circumferential side of the peripheral wall portion, the flexible piece is provided so as to be inclined inwardly toward a tip end in an axial direction when not fastened to the female connector, when the coupler is fastened, the inclination angle of the flexible piece does not change toward the inner periphery from when the flexible piece abuts against the plug until the axial movement of the coupler relative to the plug is restricted, A medical male connector in which the inclination of the flexible piece gradually decreases as it moves along the guide surface as it is tightened into the female connector, so that the flexible piece is approximately parallel to the axial direction of the coupler when tightened into the female connector.

Images