Needleless Connector

Abstract

To provide a novel needleless connector which can effectively suppress elongation when being connected to a male connector by excessive force.SOLUTION: A needleless connector 10 is such that: a cylindrical support part 70 extending inward in an axial direction in a disc-like elastic valve body 14 is sandwiched and mounted in a thickness direction by an outside holding part 22 and an inside holding part 20 constituting a cylindrical opening part 12; a male screw 60 is disposed on an outer peripheral surface of the outside holding part 22; and a lure lock-type male connector 56 is screwed and connected with the male screw 60. In the needleless connector, an axial direction undersurface 90 of a screw thread 62 of the male screw 60 has an inclination angle in a range of 15-40 degrees to a central axial direction of the opening part 12.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a needleless connector having a male thread provided on an outer peripheral surface and being connectable to a luer lock type male connector.

Background Art

[0002] Conventionally, in a fluid flow path for performing infusion, blood transfusion, etc. in the medical field, as a type of connection connector, a needleless connector that can perform mixing injection with a syringe or connection of an infusion set without using a metal needle has been used. The needleless connector includes a female connection portion provided with a valve body, and a male thread for screwing and fixing a male connector with a luer lock is formed on an outer peripheral surface of the female connection portion. The specific structure of the needleless connector of the conventional structure is disclosed in, for example, International Publication No. 2015 / 156272 (Patent Document 1).

[0003] By the way, at the connection portion of a male connector such as a syringe to the female connection portion of the needleless connector, it is necessary to avoid leakage of fluid and accidental disconnection of the connector. Therefore, the luer lock of the male connector should be firmly tightened and screwed to the female connection portion of the needleless connector.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in a conventional needleless connector, due to the awareness of firmly screwing and fixing a male connector such as a syringe to the female connection part of the needleless connector, there are cases where it is tightened with an excessively large force. Especially when it is necessary to connect quickly at the medical site, it is difficult to adjust the force and set an accurate tightening force.

[0006] On the other hand, as a result of the inventor's study, in a conventional needleless connector, when tightened with an excessively large force, the female connection part may be deformed so as to extend in the axial direction (flow path length direction). When such deformation occurs, the member strength of the female connection part of the needleless connector decreases, it becomes difficult to sufficiently obtain the tightening force by the male and female screws, and there is also a possibility that a gap is generated at the screwing part of the male and female screws, leading to fluid leakage.

[0007] In particular, in a conventional needleless connector, for the purpose of ensuring the support strength of the valve body, etc., a cylindrical support part extending inward in the axial direction from the outer peripheral part of the valve body is provided, and the cylindrical support part is sandwiched and supported in the thickness direction by an outer holding part and an inner holding part constituting the female connection part. However, in such a structure, the outer holding part on which the male screw of the female connection part is formed on the outer peripheral surface is likely to be thin. Therefore, when the male connector is tightened with a large force, deformation such as extending in the axial direction is more likely to occur in the outer holding part of the female connection part.

[0008] The problem to be solved by the present invention is to provide a novel needleless connector that can suppress problems caused by deformation such as elongation of the female connection part of the needleless connector even when the tightening force of a male connector such as a syringe screwed to the female connection part of the needleless connector becomes large.

Means for Solving the Problem

[0009] The following describes preferred embodiments for understanding the present invention. However, each of the embodiments described below is described by way of example, and not only can they be adopted in appropriate combinations with each other, but also with respect to the plurality of components described in each embodiment, they can be recognized and adopted as independently as possible, and can also be adopted in appropriate combination with any of the components described in other embodiments. Accordingly, in the present invention, various other embodiments can be realized without being limited to the embodiments described below.

[0010] In a first aspect, in a disk-shaped elastic valve body, a cylindrical support portion extending inward in the axial direction is sandwiched and mounted in the thickness direction by an outer holding portion and an inner holding portion that constitute a cylindrical opening portion, and a male thread is provided on the outer peripheral surface of the outer holding portion. In a needleless connector in which a luer lock type male connector can be screwed and connected to the male thread, the axial lower surface of the thread crest of the male thread is set at an inclination angle within a range of 15 degrees to 40 degrees with respect to the central axis direction of the opening portion.

[0011] In the needleless connector of this aspect, the inclination angle of the axial lower surface of the thread crest of the male thread formed on the outer holding portion at the opening portion is set smaller (gentler) than that of the needleless connector with a conventional structure. And when the male connector is tightened with a large force, before the cylindrical wall of the outer holding portion reaches the yield point (tensile yield stress) due to the axial fixing force exerted on the opening portion by the male and female threads, the female thread formed on the male connector easily rides on the thread crest of the male thread formed on the outer holding portion. Therefore, even when the male connector is tightened with a large force, it is possible to prevent large deformations such as elongation in the cylindrical wall of the outer holding portion from occurring suddenly, and an effective tightened state can be maintained. As a result, when screwing and connecting the male connector to the opening portion of the needleless connector, the allowable range of the tightening force and tightening amount of the male and female threads required to obtain an appropriate screw fixing force is increased, and the connection operation of the male connector to the needleless connector can be easily and surely performed.

[0012] In the second aspect, a cylindrical support portion extending inward in the axial direction in a disk-shaped elastic valve body is sandwiched and mounted in the thickness direction by an outer holding portion and an inner holding portion that constitute a cylindrical opening portion, and a male thread is provided on the outer peripheral surface of the outer holding portion. A needleless connector is configured such that a luer lock type male connector can be screwed and connected to the male thread, and the entire portion where the height dimension is maximum on the thread crest of the male thread is located above the axial center of the thread crest of the male thread.

[0013] In the needleless connector of this aspect, below the axial center of the thread crest of the male thread, the protruding height of the thread crest is made smaller than that of the portion where the height is maximum. Therefore, when the male and female threads are screwed together, the thread crest of the female thread is easily lifted onto the axial lower surface of the thread crest of the male thread. Therefore, even when the male and female threads are tightened excessively, the upward force exerted on the male thread from the female thread can be kept small, and the elongation of the cylindrical wall of the outer holding portion can be prevented.

[0014] The third aspect is According to the first or second aspect In the needleless connector, both the axial upper and lower surfaces of the thread crest of the male thread are inclined surfaces that approach the mating side as they go to the outer peripheral side, and the thread crest of the male thread has a shape that is biased upward.

[0015] In the needleless connector of this aspect, the inclination angle of the axial lower surface of the thread crest of the male thread with respect to the central axis direction is made smaller than the inclination angle of the axial upper surface of the thread crest of the male thread with respect to the central axis direction. Therefore, when the male connector is tightened with a large force, the thread crest of the female thread is easily lifted onto the axial lower surface of the thread crest of the male thread. Therefore, deformation such as elongation of the cylindrical wall of the outer holding portion of the needleless connector can be prevented. Further, since the axial upper surface of the thread crest of the male thread inclines downward as it goes to the outer peripheral side, the movement of the thread crest of the female thread can be guided by the axial upper surface.

[0016] The fourth aspect is the needleless connector according to any one of the first to third aspects, wherein the wall thickness dimension of the cylindrical wall of the outer holding portion formed with the male thread is 2.0 mm or less.

[0017] In the needleless connector of this aspect, while ensuring the screw fixing force of the luer lock, the cylindrical wall of the outer holding portion can be designed to be thin, so that it is possible to avoid the outer diameter dimension of the needleless connector becoming too large.

Advantages of the Invention

[0018] According to the needleless connector of the present invention, even when a large screw fixing force is applied, the deformation of the cylindrical wall portion is suppressed, and a stable connector connection state by screw fixing can be realized.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0020] Hereinafter, in order to further clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

[0021] First, FIGS. 1 and 2 show a needleless connector 10 as a first embodiment of the present invention. The needleless connector 10 of this embodiment is generally in the shape of a straight, substantially cylindrical plug. Further, it has a cylindrical opening portion 12 protruding from one side in the axial direction (the upper side in FIG. 2), and a disc-shaped elastic valve body 14 is attached to the upper end (opening end) of the opening portion 12. Note that the axial direction refers to the vertical direction in FIGS. 1 and 2, which is the central axis direction of the needleless connector 10. Also, the upper side refers to the upper side in FIGS. 1 and 2, and the lower side refers to the lower side in FIGS. 1 and 2.

[0022] More specifically, the housing 16 of the needleless connector 10 is constituted by coaxially combining three separate members, namely, a base member 18, an inner holding portion 20, and an outer holding portion 22, each having a substantially cylindrical shape. The materials of these base member 18, inner holding portion 20, and outer holding portion 22 are not limited as long as they are hard synthetic resins. For example, polypropylene, polyvinyl chloride, polycarbonate, polyacetal resin (POM), etc. can be preferably adopted.

[0023] The base member 18 includes a central cylindrical portion 24 that extends vertically in the axial direction and protrudes downward to form a male connection portion, and a substantially cylindrical peripheral wall portion 26 located on the outer peripheral side of the central cylindrical portion 24. The central cylindrical portion 24 and the peripheral wall portion 26 are connected by a substantially annular upper bottom wall portion 28 that extends in a direction perpendicular to the axis. The central cylindrical portion 24 penetrates the central portion of the upper bottom wall portion 28 in the vertical direction, and the central cylindrical portion 24 protrudes on both sides in the vertical direction with respect to the upper bottom wall portion 28. Further, the peripheral wall portion 26 protrudes downward from the upper bottom wall portion 28, and a female thread 30 is formed on the inner peripheral surface of the peripheral wall portion 26.

[0024] Furthermore, a substantially cylindrical support wall portion 32 protrudes upward at a radially intermediate portion on the upper surface of the upper bottom wall portion 28. Then, a substantially annular fixing groove 34 that opens upward is formed on the upper surface of the upper bottom wall portion 28 by the central cylindrical portion 24 and the support wall portion 32 that protrude upward from the upper bottom wall portion 28.

[0025] On the one hand, the inner holding portion 20 is formed in a tapered cylinder shape that gradually decreases in diameter upward as a whole, and the lower end portion of the inner holding portion 20 is formed as a substantially annular-shaped annular base end portion 36 that protrudes to the outer peripheral side. Further, an annular receiving portion 38 that narrows toward the inner peripheral side is formed at the upper end portion of the inner holding portion 20, and an annular inner engaging claw 40 that protrudes upward is formed at the inner peripheral edge portion of the receiving portion 38.

[0026] Furthermore, the outer holding portion 22 is formed in a stepped cylinder shape as a whole, and has a structure in which a lower large-diameter cylinder portion 42 and an upper small-diameter cylinder portion 44 are integrally connected by a stepped annular wall portion 46 that extends in a direction perpendicular to the axis. That is, an annular wall portion 46 is provided in the middle portion in the axial direction of the outer holding portion 22, the portion below the annular wall portion 46 is the large-diameter cylinder portion 42, and the portion above the annular wall portion 46 is the small-diameter cylinder portion 44. A substantially annular fitting groove 48 that opens downward is formed in the radial middle portion of the lower surface of the annular wall portion 46.

[0027] The small-diameter cylinder portion 44 is formed in a tapered cylinder shape that gradually decreases in diameter upward as a whole. Further, a substantially annular-shaped tip wall portion 50 that protrudes to the inner peripheral side is provided at the upper end portion of the small-diameter cylinder portion 44, and an annular outer engaging claw 52 that protrudes downward in a folded-back manner is provided at the inner peripheral edge portion of the tip wall portion 50. An annular outer holding groove 54 that opens downward is formed between the small-diameter cylinder portion 44 and the outer engaging claw 52 in the radial direction.

[0028] Here, a female connection portion is configured including the small-diameter cylinder portion 44, and a male screw 60 that is screwed into a female screw 58 (see FIG. 3 described later) provided on a luer lock type male connector 56 is formed on the outer peripheral surface of the small-diameter cylinder portion 44. This male screw 60 is a double screw that can be connected to the female screw 58 defined by, for example, ISO80369-7 (ISO594-2). In the present embodiment, the male screw 60 is formed over substantially the entire length in the vertical direction of the small-diameter cylinder portion 44. Specifically, it is formed from slightly above the annular wall portion 46 to the vertical position substantially corresponding to the protruding tip of the outer engaging claw 52.

[0029] In consideration of the size of a general luer lock structure, the outer diameter dimension of the small-diameter cylindrical portion 44 that does not include the thread 62 of the male thread 60 is preferably set within the range of 5.0 mm to 7.0 mm. However, in the present embodiment, the small-diameter cylindrical portion 44 is configured such that the outer diameter dimension gradually increases downward as a whole. Along with this, the height dimension of the thread 62 of the male thread 60 gradually decreases downward. As a result, the outer diameter dimension of the apex of the thread 62 of the male thread 60 is substantially constant in the vertical direction in the formed portion of the male thread 60.

[0030] In the present embodiment, each of the two threads constituting the male thread 60 is formed on the outer peripheral surface of the small-diameter cylindrical portion 44 with a length of half a turn or more. Preferably, each thread of the male thread 60 is formed with a length of approximately one turn. By adopting a two-thread structure, it is possible to improve the screw fixing force while suppressing the amount of rotation during screw fixing compared to a single-thread structure.

[0031] Also, in the present embodiment, the thickness dimension A (see FIG. 2) of the small-diameter cylindrical portion 44 in the formed portion of the male thread 60 is set to 2.0 mm or less, and for example, A may be set to 1.0 mm or less. If the thickness dimension A of the small-diameter cylindrical portion 44 becomes larger than 2.0 mm, it may be difficult to secure the outer diameter dimension according to standards such as ISO and the inner diameter dimension of the connector internal flow path while ensuring the support structure of the elastic valve body 14 described later. Note that the thickness dimension of the small-diameter cylindrical portion 44 refers to the thickness dimension of the cylindrical portion that does not include the thread 62 of the male thread 60.

[0032] In the small-diameter cylindrical portion 44 of the present embodiment, the thickness dimensions of the bottom wall and the outer peripheral wall of the outer holding groove 54 are larger than the thickness dimension of the small-diameter cylindrical portion 44 in the formed region of the male thread 60. That is, the circumferential wall region of the small-diameter cylindrical portion 44 where the male thread 60 is formed is a thin-walled portion 64 with a smaller thickness dimension than the tip opening portion.

[0033] And the opening portion 12 is configured to include the inner holding portion 20 and the outer holding portion 22 described above, and the elastic valve body 14 disposed at the upper opening of the opening portion 12 is held at the outer peripheral portion.

[0034] The elastic valve body 14 is substantially disk-shaped and is formed of an elastic body such as rubber or elastomer. Further, a slit 68 penetrating in the thickness direction is formed in the central portion 66 of the elastic valve body 14. The shape of the slit 68 is not limited, and for example, it can be linear, cross-shaped, or radially extending from the center.

[0035] Also, a cylindrical support portion 70 protruding axially inward (downward in FIGS. 1 and 2) is provided on the outer peripheral portion of the elastic valve body 14. Further, the central portion 66 and the cylindrical support portion 70 are connected by an annular connecting portion 72 extending over the entire circumference in the circumferential direction, whereby the elastic valve body 14 is formed as an integrally molded product.

[0036] This annular connecting portion 72 is formed by making the thickness dimension smaller than that of the central portion 66 of the elastic valve body 14. Groove-shaped outer annular grooves 74 and inner annular grooves 76 extending over the entire circumference in the circumferential direction are formed on the outer peripheral portions of both the inner and outer surfaces in the axial direction of the elastic valve body 14. By these two annular grooves 74 and 76, a constriction is formed in the outer peripheral portion of the elastic valve body 14, and this constricted portion, that is, the axial interval between the bottoms of the two annular grooves 74 and 76, is the thin-walled annular connecting portion 72.

[0037] Note that the shapes of the two annular grooves 74 and 76 respectively substantially correspond to the outer engaging claws 52 and the inner engaging claws 40, and the outer and inner engaging claws 52 and 40 are fitted therein. Further, a concave groove portion 78 is formed in the wall portion on the inner peripheral side of the inner annular groove 76, and the inner surface shape of the concave groove portion 78 substantially corresponds to the inner peripheral surface shape of the inner engaging claw 40. Note that the concave groove portion 78 may be continuous in the circumferential direction to form an annular shape, or may be provided partially by being divided in the circumferential direction.

[0038] In this embodiment, the cylindrical support portion 70 protrudes above the annular connection portion 72. That is, the cylindrical support portion 70 is configured to include an upper support portion 80 protruding upward from the annular connection portion 72 and a lower support portion 82 protruding downward from the annular connection portion 72. Note that an annular flange-shaped portion 84 protruding to the outer peripheral side is integrally formed at the lower end of the lower support portion 82.

[0039] In the elastic valve body 14, the outer diameter dimension at the upper end portion of the upper support portion 80 is preferably set within the range of 5.0 to 6.5 mm. If the dimension is smaller than 5.0 mm, it may be difficult to insert the luer tip of a standard luer lock type male connector 56 having an outer diameter unified to approximately 4.0 mm (for example, defined in ISO80369-7 (ISO594-2)). On the other hand, if the dimension is larger than 6.5 mm, the outer diameter of the small diameter cylindrical portion 44 becomes large, and it may be difficult to connect with the female thread 58 of the standard luer lock type male connector 56.

[0040] The annular base end portion 36 of the inner holding portion 20 is fitted into the fixing groove 34 of the base member 18, the lower support portion 82 of the elastic valve body 14 is assembled to the inner holding portion 20 in an externally inserted state, and further, the outer holding portion 22 is assembled to the lower support portion 82 of the elastic valve body 14 in an externally inserted state. Note that the lower support portion 82 and the flange-shaped portion 84 of the elastic valve body 14 are overlapped with the base member 18, the inner holding portion 20, and the outer holding portion 22 in a substantially close state, and their overlapping surfaces may be adhered or non-adhered.

[0041] In addition, the inner and outer engaging claws 40 and 52 formed on the inner and outer holding portions 20 and 22 are pressed into the inner and outer annular grooves 76 and 74 of the elastic valve body 14 so as to bite in. Furthermore, on the flange-shaped portion 84 of the elastic valve body 14, locking protrusions protruding from the upper surface of the annular base end portion 36 of the inner holding portion 20 and the lower surface of the annular wall portion 46 of the outer holding portion 22 are pressed so as to bite in respectively.

[0042] The outer holding portion 22 is welded while being axially pressed against the base member 18, and the elastic valve body 14 is assembled and mounted in the housing 16. Note that the outer holding portion 22 and the base member 18 may be fixed by means such as adhesion or concavo-convex fitting instead of or in addition to welding. Further, in FIG. 2, a welding projection is shown by a two-dot chain line at the upper end of the support wall portion 32 of the base member 18 that is fitted into the fitting groove 48 of the outer holding portion 22. However, when the outer holding portion 22 and the base member 18 are welded, the welding site is not limited.

[0043] Accordingly, in the present embodiment, the lower support portion 82 of the cylindrical support portion 70 is sandwiched and supported in the thickness direction between the outer holding portion 22 and the inner holding portion 20, and preferably is supported in a compressed state in the radial direction between the outer holding portion 22 and the inner holding portion 20. As a result, the elastic valve body 14 is effectively prevented from falling off from the housing 16.

[0044] Here, in the present embodiment, the male thread 60 provided on the outer peripheral surface of the small-diameter cylindrical portion 44 is a trapezoidal thread in which the cross-sectional shape of the thread crest 62 is substantially trapezoidal, and the thread crest 62 has a protruding tip surface 86 that extends substantially parallel to the cylindrical surface around the central axis, and an axially upper surface 88 and an axially lower surface 90 that are inclined from both axial sides of the protruding tip surface 86. These axially upper and lower surfaces 88 and 90 are inclined surfaces that are inclined with respect to the axial direction, and approach each other as they go to the outer peripheral side. Note that the inclination angles of the axially upper surface 88 and the axially lower surface 90 are substantially constant over the entire length of the male thread 60. Further, in FIG. 2, the thread shape described in Patent Document 1 is shown by a one-dot chain line as a reference example of the thread shape of the conventional structure.

[0045] And in the present embodiment, in the axial cross-section shown in FIG. 2, the inclination angle α (see FIG. 2) of the axial lower surface 90 with respect to the axial line is smaller than that of the conventional structure, and the inclination angle α is 15 degrees or more. When the inclination angle α is smaller than 15 degrees, the engaging force between the male screw 60 and the female screw 58 becomes small, making it difficult to obtain a sufficiently large screw fixing force, or there is a risk that the male connector 56 may easily come off axially from the needleless connector 10. Further, the inclination angle α is 40 degrees or less. When the inclination angle α is larger than 40 degrees, when a large screw tightening force acts during the connection of the male connector 56 described later, it may be difficult to suppress deformation such as elongation of the small-diameter cylindrical portion 44 in which the male screw 60 is formed in the needleless connector 10.

[0046] Furthermore, in the present embodiment, in the axial cross-section shown in FIG. 2, the inclination angle β (see FIG. 2) of the axial upper surface 88 with respect to the axial line is 60 degrees or more. When the inclination angle β is smaller than 60 degrees, when the thread 62 of the male screw 60 and the thread 92 of the female screw 58 (see FIG. 3) come into contact during the screwing of the male screw 60 and the female screw 58, the thread 92 of the female screw 58 may be displaced so as to slide to the outer peripheral side of the thread 62 of the male screw 60, and there is a risk that the screwing of the male screw 60 and the female screw 58 may not be sufficiently achieved. Moreover, the inclination angle β is less than 90 degrees. When the inclination angle β is 90 degrees or more, there is a risk that screwing with a standard male connector 56 (for example, defined in ISO80369-7 (ISO594-2)) may become difficult.

[0047] In particular, in the present embodiment, the inclination angle β at the upper axial surface 88 is made larger than the inclination angle α at the lower axial surface 90. As a result, the axial dimension at the lower axial surface 90 is larger than the axial dimension at the upper axial surface 88, and the protruding tip surface 86 provided between the upper and lower axial surfaces 88 and 90 is biased and positioned above the thread 62. That is, the thread 62 has a shape in which the portion with the maximum height dimension is biased upward. Further, in the present embodiment, the axial center (L1 in FIG. 2) of the portion where the height dimension of the thread 62 is maximum is located above the axial center (L2 in FIG. 2) of the thread 62. In particular, in the present embodiment, the entire portion where the height dimension of the thread 62 is maximum is located above the axial center of the thread 62.

[0048] Also, the maximum height dimension B (see FIG. 2) of the thread 62 is preferably 0.3 mm or more. When the maximum height dimension B is less than 0.3 mm, it may be difficult to sufficiently ensure the engagement force between the male thread 60 and the female thread 58. On the other hand, the maximum height dimension B is preferably 1.5 mm or less. When the maximum height dimension B is greater than 1.5 mm, considering the screwing with the female thread 58 of a general male connector 56 conforming to the ISO standard, it may be difficult to ensure the thickness dimension of the small-diameter cylindrical portion 44.

[0049] Furthermore, in the present embodiment, in the axial cross-section shown in FIG. 2, the width dimension C of the protruding tip surface 86 of the thread 62 assuming a trapezoidal thread is set smaller than that of the conventional structure (the dashed-dotted line in FIG. 2). The width dimension C of the protruding tip surface 86 is preferably 0.3 mm or more. When the width dimension C of the protruding tip surface 86 is less than 0.3 mm, it becomes difficult to sufficiently ensure the height of the thread 62 under the conditions of the inclination angles β and α at the upper and lower axial surfaces 88 and 90, and there is a risk that it becomes difficult to sufficiently obtain the screw fixing force due to the engagement between the male thread 60 and the female thread 58. On the other hand, the width dimension C of the protruding tip surface 86 is preferably 1.2 mm or less. When the width dimension C of the protruding tip surface 86 is greater than 1.2 mm, it may be difficult to form the male thread 60 suitable for connection with a general male connector conforming to the ISO standard or the like.

[0050] The needleless connector 10 having the shape as described above is configured such that, as shown in FIG. 3, when the male luer of the male connector 56 is inserted into the slit 68 of the elastic valve body 14 and the male screw 60 and the female screw 58 are screwed together, the needleless connector 10 and the male connector 56 are interconnected. In FIG. 3, the male connector 56 is shown by a dashed-dotted line, and the portion of the male luer is not shown.

[0051] In a needleless connector of a conventional structure (shown by a one-dot chain line in FIG. 3), when the male screw and the female screw 58 are screwed together, the thread of the male screw and the thread 92 of the female screw 58 come into contact with each other and mesh at the portion where the one-dot chain line and the dashed-dotted line overlap. Since the contact surface of such meshing male and female screws is largely inclined with respect to the central axis, when the male connector 56 is strongly tightened and a large torque is applied, the axial force converted by the screw mechanism is directly applied from the male screw 60 to the small-diameter cylindrical portion 44. As a result, stress concentrates on the thin-walled portion 64 of the small-diameter cylindrical portion 44 which is thinner than the male screw 60, and axial elongation deformation is likely to occur. When axial elongation deformation occurs in the thin-walled portion 64, since the situation has already exceeded the tensile yield point, not only is it difficult to ensure the tightening and fixing force for the needleless connector 10 while remaining low even when the male connector 56 is tightened further, but there is also a risk that a gap will occur in the meshing surface of the male and female screws and fluid will leak.

[0052] In contrast, in the present embodiment, since the inclination angle α of the axially lower surface 90 of the thread 62 of the male screw 60 is set small, when a large tightening force acts during the screwing of the male screw 60 and the female screw 58, the thread 92 of the female screw 58 easily rides on the axially lower surface 90 of the thread 62. In this way, by the thread 92 of the female screw 58 riding on the axially lower surface 90 of the thread 62, it is possible to avoid the axial tensile force exerted on the small-diameter cylindrical portion 44 due to the screwing of the female screw 58 and the male screw 60 from becoming excessive, and the small-diameter cylindrical portion 44 can be prevented from stretching. Further, since the small-diameter cylindrical portion 44 does not reach the tensile yield point, the screwing force of the male connector 56 to the needleless connector by the screwing of the male and female screws 58, 60 can also be effectively maintained.

[0053] In particular, in the present embodiment, in the axial cross-section shown in FIG. 2, the axially upper and lower surfaces 88, 90 of the thread 62 are inclined surfaces inclined with respect to the axial direction, and the inclination angle α of the axially lower surface 90 is made smaller than the inclination angle β of the axially upper surface 88. As a result, the portion where the height dimension of the thread 62 is the largest is biased upward of the thread 62. In the present embodiment, the entire portion where the height dimension of the thread 62 is the largest is located above the axial center of the thread 62. As a result, the thread 92 of the female screw 58 easily rides on the axially lower surface 90 of the male screw 60, and by the thread 92 riding on the axially lower surface 90, the meshing amount of both threads 62, 92 is suppressed to be small, that is, the axial tensile force exerted on the small-diameter cylindrical portion 44 is suppressed to be small, so that the elongation of the small-diameter cylindrical portion 44 can be prevented.

[0054] Further, the axially upper surface 88 of the thread 62 is an inclined surface inclined with respect to the axial direction, and by appropriately setting the inclination angle of the axially upper surface 88, the movement of the thread 92 of the female screw 58 in contact with the thread 62 of the male screw 60 can be guided.

[0055] The inventors of the present invention prototyped the needleless connector 10 of the present embodiment as an example and confirmed that the elongation of the housing 16 (small-diameter cylindrical portion 44) was prevented. The results are shown in FIG. 4. As a comparative example, the needleless connector described in Patent Document 1 was used. Also, in both the example and the comparative example, as the male connector 56 inserted into the elastic valve body 14, "Raw Food Injection Syringe 'Otsuka' 20 mL" manufactured by Otsuka Pharmaceutical Factory, Inc. was used, and when the male screw 60 was deformed and the female screw 58 was screwed until it rotated freely, the torque applied to the male connector 56 and the elongation of the housing 16 (small-diameter cylindrical portion 44) were measured.

[0056] As shown in FIG. 4, it can be seen that in the example, compared with the comparative example, the torque until the female screw 58 starts to rotate freely is increased, and the maximum elongation distance of the housing is also kept small.

[0057] Next, FIG. 5 shows a needleless connector 100 as a second embodiment of the present invention. Also in this embodiment, compared with the needleless connector described in Patent Document 1 as a conventional structure, the shape of the thread 104 of the male screw 102 is different.

[0058] For members and parts that are substantially the same as those in the first embodiment, the same reference numerals as those in the first embodiment are given in the figure, and detailed description is omitted. Also, in the needleless connector 100 of this embodiment, various synthetic resins can be adopted as the material of the outer holding portion 22 in which the male screw 102 is formed. For example, polypropylene, polyvinyl chloride, polycarbonate, polyacetal resin (POM), etc. can be adopted.

[0059] The thread 104 of the male screw 102 of this embodiment has a smaller height dimension compared with the conventional structure, and the maximum height dimension B' (see FIG. 5) of the thread 104 is set within the range of 0.3 to 1.5 mm.

[0060] When the maximum height dimension B' is less than 0.3 mm, when tightening the male connector 56, it may be difficult to sufficiently obtain the tightening force of the screw structure, for example, by the male screw 102 overcoming the female screw. On the other hand, when the maximum height dimension B' is greater than 1.5 mm, when a large screw tightening force acts during the connection of the male connector 56 described later, it may be difficult to suppress deformation such as the elongation of the small-diameter cylindrical portion 44 in which the male screw 102 is formed in the needleless connector 100.

[0061] Also, in the present embodiment, the inclination angle α' (see FIG. 5) of the axial-direction lower surface 90 of the thread 104 of the male screw 102 with respect to the axial direction is set smaller than that of the conventional structure, and is smaller than the inclination angle β of the axial-direction upper surface 88 with respect to the axial direction. As a result, also in the present embodiment, the width dimension C' (see FIG. 5) of the protruding tip surface 86 of the thread 104 is made smaller than that of the conventional structure, and the thread 104 has a shape in which the portion with the maximum height dimension is biased upward. That is, in the thread 104, the axial center (L1) of the portion with the maximum height dimension is located above the axial center (L2) of the thread 104.

[0062] In the needleless connector 100 of the present embodiment having the shape as described above, when the tightening torque during the connection operation of the male connector generally assumed for the male connector 56 is applied, the screw fixing force due to the engagement of the male screw 102 and the female screw 58 is exerted. On the other hand, in addition to the thread 104 of the male screw 102 having an upwardly biased shape, since the maximum height dimension B' of the thread 104 is made smaller, when a tightening torque larger than expected is applied to the male connector 56, the thread 92 of the female screw 58 easily rides up on the thread 104 of the male screw 102. In this way, by the thread 92 of the female screw 58 riding up on the thread 104, it is possible to avoid an excessive axial tensile force exerted on the small-diameter cylindrical portion 44 by the screwing of the male and female screws 58 and 102. Therefore, similar to the first embodiment, the elongation of the small-diameter cylindrical portion 44 can be prevented, and since the small-diameter cylindrical portion 44 does not reach the tensile yield point, the screw fixing force of the male connector 56 to the needleless connector 100 by the screwing of the male and female screws 58 and 102 can also be effectively maintained.

[0063] The embodiments of the present invention have been described above. However, the present invention is not to be construed as being limited to the specific descriptions in these embodiments, and can be implemented in various forms with various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art.

[0064] For example, the shape of the male connector inserted into the needleless connector is not limited as long as it has a female thread that engages with the male thread of the needleless connector, and is not limited to that defined in ISO80369-7 (ISO594-2). Also, the male thread provided on the needleless connector is not limited to the trapezoidal thread structure according to ISO80369-7 (ISO594-2). For example, a saw blade thread, a triangular thread, etc. can also be adopted. Preferably, it has a thread structure that satisfies the functions defined in ISO80369 (ISO594), but the shapes of the male and female threads, etc. are not limited, and the engagement rate and engagement width of the male and female threads can also be appropriately set in consideration of materials, thread length, etc.

[0065] Also, the small-diameter cylindrical portion 44 may have an outer peripheral surface shape that is not inclined, i.e., a straight cylindrical shape, in addition to the tapered cylindrical outer peripheral surface shape as in the embodiment. Furthermore, the male thread 60 formed on the small-diameter cylindrical portion 44 is not limited to a multi-thread structure, and may be a single-thread structure.

[0066] Also, as in the second embodiment, the aspect of making the inclination angle of the axial lower surface of the thread crest of the male thread smaller with respect to the axial direction than the conventional structure and the aspect of making the maximum height dimension of the thread crest of the male thread smaller than the conventional structure may be combined and adopted. By combining and adopting these, it is also possible to make the inclination angle of the axial lower surface of the thread crest with respect to the axial direction larger than that in the first embodiment. Thereby, while preventing the elongation of the housing, the connection strength between the needleless connector and the male connector can also be improved.

[0067] Note that the inclination angles β and α of the axial upper and lower surfaces 88 and 90 on the threads 62 and 104 of the male threads 60 and 102 are not limited in any way. For example, in the threads of the male thread, when the entire portion with the maximum height dimension is located above the axial center of the threads of the male thread, the inclination angle of the axial lower surface may be approximately equal to that of the needleless connector described in Patent Document 1 having a conventional structure. Further, the inclination angle of the axial upper surface may be, for example, 90 degrees.

[0068] Furthermore, in the above-described embodiment, the housing 16 was composed of three members, namely, the base member 18, the inner holding portion 20, and the outer holding portion 22. However, for example, the base member and the inner holding portion may be integrally formed, or the entire housing may be integrally formed.

[0069] Furthermore, in the above-described embodiment, the cylindrical support portion 70 of the elastic valve body 14 extended axially inward beyond the annular wall portion 46 of the outer holding portion 22. However, the shape of the elastic valve body is not limited to that described in the above-described embodiment. For example, the cylindrical support portion may extend only axially outward beyond the annular wall portion of the outer holding portion. Note that when the cylindrical support portion extends axially inward beyond the annular wall portion of the outer holding portion, effects such as further improving the support force for preventing the elastic valve body from falling off and preventing deformation of the female connection portion (outer holding portion) during screwing connection of the male connector can be more advantageously exhibited. However, the male thread provided on the needleless connector is not limited to the mode of being provided over the entire axial length in the small-diameter cylindrical portion of the outer holding portion, and may be provided partially axially in the small-diameter cylindrical portion of the outer holding portion.

[0070] Note that in the above-described embodiment, the base portion (base member 18) of the needleless connector 10 was in a plug shape having a male connection portion (central cylindrical portion 24), but it is not limited thereto. By appropriately changing the shape and structure of the housing, the needleless connector may be, for example, a three-way stopcock, a mixing tube, a structure attached to a bag in which a chemical solution is enclosed, or the like. In addition, the present invention originally includes each of the inventions described in the following (i) to (iv), and the configuration, operation, and effects thereof will be described below for reference. The present invention (i) In a needleless connector in which a cylindrical support portion extending inward in the axial direction in a disk-shaped elastic valve body is sandwiched and mounted in the thickness direction by an outer holding portion and an inner holding portion that constitute a cylindrical opening portion, a male thread is provided on the outer peripheral surface of the outer holding portion, and a luer lock type male connector can be screwed and connected to the male thread. The axial lower surface of the thread of the male thread has an inclination angle within a range of 15 degrees to 40 degrees with respect to the central axis direction of the opening portion. (ii) A needleless connector in which a cylindrical support portion extending inward in the axial direction in a disk-shaped elastic valve body is sandwiched and mounted in the thickness direction by an outer holding portion and an inner holding portion that constitute a cylindrical opening portion, a male thread is provided on the outer peripheral surface of the outer holding portion, and a luer lock type male connector can be screwed and connected to the male thread. The entire portion where the height dimension is maximum on the thread of the male thread is located above the axial center of the thread of the male thread. (iii) In a needleless connector in which a cylindrical support portion extending inward in the axial direction in a disk-shaped elastic valve body is sandwiched and mounted in the thickness direction by an outer holding portion and an inner holding portion that constitute a cylindrical opening portion, a male thread is provided on the outer peripheral surface of the outer holding portion, and a luer lock type male connector can be screwed and connected to the male thread. The axial upper and lower surfaces of the thread of the male thread are both inclined surfaces that incline in a direction approaching the mating part as they go to the outer peripheral side, and the thread of the male thread has a shape biased upward. (iv) The needleless connector according to any one of claims 1 to 3, wherein the wall thickness dimension of the cylindrical wall of the outer holding portion on which the male thread is formed is 2.0 mm or less. including the invention related thereto. In the invention described in (i) above, the inclination angle of the thread flank on the axial lower surface of the male thread formed on the outer holding portion at the opening is set to be smaller (gentler) than that of the conventional needleless connector. When the male connector is tightened with a large force, before the cylindrical wall of the outer holding portion reaches the yield point (tensile yield stress) due to the axial fixing force exerted on the opening by the male and female threads, the female thread formed on the male connector easily rides up on the thread flank of the male thread formed on the outer holding portion. Therefore, even when the male connector is tightened with a large force, it is possible to prevent large deformations such as elongation from occurring in the cylindrical wall of the outer holding portion, and an effective tightened state can be maintained. As a result, when screwing and connecting the male connector to the opening of the needleless connector, the allowable range of the tightening force and tightening amount of the male and female threads required to obtain an appropriate screw fixing force is increased, and the connection operation of the male connector to the needleless connector can be easily and surely performed. In the invention described in (ii) above, since the protrusion height of the thread flank is smaller than the maximum at the lower side of the axial center of the thread flank of the male thread, when the male and female threads are screwed together, the thread flank of the female thread easily rides up on the axial lower surface of the thread flank of the male thread. Therefore, even when the male and female threads are overly tightened, the upward force exerted by the female thread on the male thread is suppressed to a small value, and elongation of the cylindrical wall of the outer holding portion can be prevented. In the invention described in (iii) above, since the inclination angle of the axial lower surface of the thread flank of the male thread with respect to the central axis direction is smaller than the inclination angle of the axial upper surface of the thread flank of the male thread with respect to the central axis direction, when the male connector is tightened with a large force, the thread flank of the female thread easily rides up on the axial lower surface of the thread flank of the male thread. Therefore, deformations such as elongation in the cylindrical wall of the outer holding portion of the needleless connector can be prevented. Further, since the axial upper surface of the thread flank of the male thread is inclined downward as it goes to the outer peripheral side, the movement of the thread flank of the female thread can be guided by the axial upper surface. In the invention described in (iv) above, in the needleless connector of this aspect, since the cylindrical wall of the outer holding portion can be designed to be thin while ensuring the screw fixing force of the luer lock, it is possible to avoid the outer diameter dimension of the needleless connector from becoming too large.

Description of Symbols

[0071] 10 Needleless connector 12 Opening part 14 Elastic valve body 16 Housing 18 Base member 20 Inner holding part 22 Outer holding part 24 Central cylindrical part 26 Peripheral wall part 28 Upper bottom wall part 30 Female thread 32 Support wall part 34 Fixing groove 36 Annular base end part 38 Receiving seat part 40 Inner engaging claw 42 Large-diameter cylindrical part 44 Small-diameter cylindrical part 46 Annular wall part 48 Fitting groove 50 Tip wall part 52 Outer engaging claw 54 Outer holding groove 56 Male connector 58 Female thread 60 Male thread 62 Thread 64 Thin-walled part 66 Central part 68 Slit 70 Cylindrical support part 72 Annular connecting part 74 Outer annular groove 76 Inner annular groove 78 Concave groove part 80 Upper support part 82 Lower support part 84 Flange-shaped part 86 Projecting tip surface 88 Axial upper surface 90 Axial lower surface 92 Thread 100 Needleless connector 102 Male thread 104 Thread

Claims

1. In a disk-shaped elastic valve body, a cylindrical support portion extending inward in the axial direction is sandwiched and mounted in the thickness direction by an outer holding portion and an inner holding portion that constitute a cylindrical opening portion, and a male thread is provided on the outer peripheral surface of the outer holding portion. In a needleless connector in which a luer lock type male connector can be screwed and connected to the male thread, A needleless connector in which the axially lower surface of the thread of the male thread has an inclination angle within a range of 15 degrees to 40 degrees with respect to the central axis direction of the opening portion.

2. In a disk-shaped elastic valve body, a cylindrical support portion extending inward in the axial direction is sandwiched and mounted in the thickness direction by an outer holding portion and an inner holding portion that constitute a cylindrical opening portion, and a male thread is provided on the outer peripheral surface of the outer holding portion. A needleless connector in which a luer lock type male connector can be screwed and connected to the male thread, A needleless connector in which the entire portion having the maximum height dimension in the thread of the male thread is located above the axial center of the thread of the male thread.

3. The needleless connector according to claim 1 or 2, wherein both the axially upper and lower surfaces of the thread of the male thread are inclined surfaces that approach the mating part in the direction of approaching as they go to the outer peripheral side, and the thread of the male thread has a shape biased upward.

4. The needleless connector according to any one of claims 1 to 3, wherein the thickness dimension of the cylindrical wall of the outer holding portion on which the male thread is formed is 2.0 mm or less.

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