Connection structure of medical instrument and syringe assembly

Abstract

A medical instrument (10) comprises a connection structure (14) that connects a first medical instrument (121) having a first screw part (661) and a second medical instrument (122) having a second screw part (662) that is to be screwed together with the first screw part (661). The connection structure has a first section (S1) at which a first engagement surface (701A) of a first screw thread (681) and a second engagement surface (702A) of a second screw thread (682) are brought into contact with each other when the first screw part (661) and the second screw part (662) are screwed together. At the first section (S1), a first angle (θ11) of the first engagement surface (701A) of the first screw thread (681) is different from a second angle (θ21) of the second engagement surface (702A) of the second screw thread (682).

Description

Medical device connection structure and syringe assembly

[0001] The present invention relates to a medical device connection structure for connecting a first medical device to a second medical device, and a syringe assembly.

[0002] Japanese Patent Application Laid-Open No. 2015-058198 relates to a syringe filled with a medicinal liquid, the tip of which is provided with a nozzle part capable of discharging the medicinal liquid.

[0003] JP 2015-058198 A

[0004] In the medical field, two medical devices are sometimes used in a form connected to each other by a threaded engagement. For example, in a syringe, a form in which the outer cylinder and the needle are connected by a threaded engagement is known. In such a structure connected by a threaded engagement, it is desirable that the threaded portion of one medical device and the threaded portion of the other medical connector device are firmly connected.

[0005] The present invention aims to solve the above-mentioned problems.

[0006] (1) An aspect of the present invention is a connection structure for medical devices that connects a first medical device having a first threaded portion to a second medical device having a second threaded portion that is threaded onto the first threaded portion, wherein the first threaded portion of the first medical device is a tapered thread having a first thread, and the second threaded portion of the second medical device is a tapered thread having a second thread that contacts the first thread of the first threaded portion, and when the first threaded portion and the second threaded portion are threaded together, a first portion is formed where a first meshing surface of the first threaded portion and a second meshing surface of the second threaded portion contact each other, the first meshing surface is inclined at a first angle with respect to a direction perpendicular to the axis of the first medical device, and the second meshing surface is inclined at a second angle with respect to a direction perpendicular to the axis of the second medical device, and the first angle of the first meshing surface of the first threaded portion and the second angle of the second meshing surface of the second threaded portion are different at the first portion.

[0007] According to this connection structure for medical devices, when the first threaded portion and the second threaded portion are threaded together, the first and second mating surfaces, which are angled differently from each other at the first portion, do not come into surface contact with each other. Therefore, when the first threaded portion and the second threaded portion are threaded together, the first threaded portion and the second threaded portion are effectively prevented from moving relative to each other in the radial direction along the first and second mating surfaces and riding up on them. This allows the first threaded portion and the second threaded portion to be firmly connected.

[0008] (2) In the connection structure for medical devices described in (1) above, the first medical device may be a syringe having a main body portion capable of being filled with a medicinal liquid, a nozzle portion provided at the tip of the main body portion, and a locking portion surrounding the nozzle portion, and the second medical device may be a puncture member having a connector having a hole portion capable of accommodating the nozzle portion and a puncture needle provided at the tip of the connector, and the locking portion may include a first tubular portion having the first screw portion on its inner surface, and the connector may include a second tubular portion having the second screw portion on its outer surface.

[0009] With this configuration, by firmly connecting the first screw portion of the first cylindrical portion and the second screw portion of the second cylindrical portion, leakage of medicinal liquid can be effectively suppressed when medicinal liquid is administered from a medical device in which a syringe and a puncture member are connected.

[0010] (3) In the connection structure for medical devices described in (2) above, the first angle of the first engagement surface of the first screw portion may be smaller than the second angle of the second engagement surface of the second screw portion.

[0011] With this configuration, when the first screw portion and the second screw portion are screwed together, the first thread of the first screw portion bites into the second meshing surface of the second thread of the second screw portion, thereby firmly connecting the first medical device (syringe) and the second medical device (puncture member).

[0012] (4) In the connection structure for medical devices described in (2) above, the second angle of the second engagement surface of the second screw portion may be smaller than the first angle of the first engagement surface of the first screw portion.

[0013] With this configuration, when the first screw portion and the second screw portion are screwed together, the second thread of the second screw portion bites into the first mating surface of the first thread of the first screw portion, thereby firmly connecting the first medical device (syringe) and the second medical device (puncture member).

[0014] (5) In the connection structure for the medical device described in (2) above, the puncture member may comprise an elastic body that is disposed in the hole portion of the connector and is pressed and compressed by the tip of the nozzle portion when the syringe is connected.

[0015] With this configuration, when the syringe and the puncture member are connected, the elastic body is compressed by the tip of the nozzle portion, so that the elastic body can effectively prevent leakage of the medicinal solution through between the tip of the syringe and the hole of the puncture member. Even if the syringe and the puncture member are urged in directions away from each other by the elastic force, riding over of the first thread and the second thread in the radial direction is effectively prevented.

[0016] (6) In the connection structure for medical devices described in (3) above, when the first threaded portion and the second threaded portion are screwed together, a second portion may be provided on the opposite side of the first portion in the connection direction between the first medical device and the second medical device, and the angle of the first non-engaging surface of the first thread in the second portion may be larger than the first angle of the first engaging surface of the first thread in the first portion.

[0017] With this configuration, the angle of the first non-meshing surface of the first thread in the second portion can be set to the same as the second angle of the second meshing surface of the second thread, so that the first screw portion can be formed more easily and at lower cost than in a configuration in which the first angle of the first meshing surface of the first thread in the first and second portions and the angle of the first non-meshing surface are both smaller than the second angle of the second meshing surface of the second thread.

[0018] (7) In the connection structure for medical devices described in (4) above, when the first threaded portion and the second threaded portion are screwed together, a second portion may be provided on the opposite side of the first portion in the connection direction between the first medical device and the second medical device, and the angle of the second non-engaging surface of the second thread in the second portion may be larger than the second angle of the second engaging surface of the second thread in the first portion.

[0019] With this configuration, the angle of the second non-meshing surface of the second thread in the second portion can be set to the same as the first angle of the first meshing surface of the first thread, so the second screw portion can be formed more easily and at lower cost than in a configuration in which the second angle of the second meshing surface of the second thread in the first and second portions and the angle of the second non-meshing surface are both smaller than the first angle of the first meshing surface of the first thread.

[0020] (8) In the connection structure for a medical device described in any one of (1) to (7) above, the difference between the first angle of the first engagement surface of the first screw portion and the second angle of the second engagement surface of the second screw portion may be less than 25°.

[0021] This configuration allows the first medical device and the second medical device to be connected more firmly.

[0022] (9) A syringe assembly including the connection structure for a medical device according to (2) above may include the syringe and the puncture member.

[0023] This configuration allows the syringe and the puncture member that constitute the syringe assembly to be firmly connected.

[0024] (10) A medical device comprising the syringe assembly described in (9) above, comprising the syringe, the puncture member, and a case in which the puncture member is housed and held, wherein the puncture member and the syringe can be connected by the first screw portion and the second screw portion when the puncture member is held inside the case, and when the syringe and the puncture member are connected, the puncture member may rotate relative to the case when a torque greater than a predetermined value is applied to the puncture member as the first screw portion and the second screw portion are threaded together.

[0025] With this configuration, even if a torque greater than a predetermined level is applied to the puncturing member, causing the puncturing member and the case to rotate relative to each other, the engagement between the first screw portion and the second screw portion is strong, so the engagement between the first screw portion and the second screw portion is effectively maintained.

[0026] According to the present invention, when the first threaded portion of the first medical device and the second threaded portion of the second medical device are threaded together, the first and second mating surfaces, which are angled differently from each other at the first location, do not come into surface contact, and therefore, when the first threaded portion and the second threaded portion are threaded together, the first threaded portion and the second threaded portion are effectively prevented from moving relative to each other in the radial direction along the first and second mating surfaces and riding up, thereby enabling a strong connection between the first threaded portion and the second threaded portion.

[0027] FIG. 1 is an overall configuration diagram of a medical device according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the medical device shown in FIG. 1. FIG. 3 is an enlarged cross-sectional view of the tip portion of the medical device shown in FIG. 1. FIG. 4 is an enlarged cross-sectional view of a connection structure in the medical device. FIG. 5 is a cross-sectional view of a puncture needle package including a puncture member. FIG. 6A is an enlarged cross-sectional view of the first threaded portion and the second threaded portion in FIG. 4. FIG. 6B is an enlarged cross-sectional view of the first threaded portion and the second threaded portion according to a modified example. FIG. 7 is an explanatory diagram illustrating the connection between the puncture member of the puncture needle package and the tip portion of a syringe. FIG. 8 is a characteristic diagram showing the relationship between the first angle of the first mating surface of the first threaded portion and the torque applied when connecting the first medical device and the second medical device. FIG. 9 is an explanatory diagram illustrating the administration of a medicinal solution after the puncture needle of the medical device has been inserted into a patient.

[0028] As shown in FIG. 1, the medical device 10 according to this embodiment includes a first medical device 121, a second medical device 122, and a connection structure 14 that connects the first medical device 121 and the second medical device 122.

[0029] 2, the first medical instrument 121 is a syringe 16. The syringe 16 is, for example, a pre-filled syringe. The syringe 16 includes a main body 18 that can be filled with a medicinal solution M, a nozzle 20 provided at the tip of the main body 18, and a locking portion 22 that surrounds the nozzle 20.

[0030] The main body 18 is formed in a cylindrical shape with an internal lumen 181. The main body 18 is formed from a transparent resin material or glass that allows the lumen 181 to be seen. The main body 18 includes a barrel 24 and a neck 26 provided at the tip of the barrel 24. The base end of the barrel 24 includes a base-end opening 241 where the lumen 181 opens, and a flange 242 that protrudes radially outward.

[0031] The neck portion 26 is formed to have a smaller diameter than the barrel portion 24. The neck portion 26 protrudes in the distal direction from the distal end of the barrel portion 24. A gasket 28 is inserted into the inner cavity 181 of the neck portion 26 through the proximal end opening 241.

[0032] As shown in FIG. 3 , gasket 28 is made of an elastic material and is housed in bore 181 so as to be axially slidable. Gasket 28 liquid-tightly seals bore 181. The portion of bore 181 distal to gasket 28 is chamber 30, which is filled with medicinal solution M. Chamber 30 is pre-filled with, for example, medicinal solution M or a liquid formulation such as injection water or saline for dilution. Gasket 28 is provided at the distal end of plunger 32, which is inserted into bore 181 of barrel portion 24. Gasket 28 is slidably operated along barrel portion 24 by plunger 32. The proximal end of plunger 32 is exposed in the proximal direction from the proximal end of main body 18 (see FIG. 1 ).

[0033] The nozzle portion 20 is provided at the tip of the neck portion 26. The nozzle portion 20 has a smaller diameter than the neck portion 26. The outer peripheral surface of the nozzle portion 20 has a luer taper that extends toward the tip. The nozzle portion 20 protrudes from the tip of the neck portion 26 toward the tip. A flow path 201 is formed inside the nozzle portion 20. The flow path 201 opens at the tip of the nozzle portion 20. The base end of the flow path 201 communicates with the lumen 181. The syringe 16 is configured to be able to eject the medicinal liquid M from the tip of the nozzle portion 20.

[0034] The locking portion 22 is provided at the tip of the neck portion 26. The locking portion 22 has a first cylindrical portion 34 that is arranged radially outward from the nozzle portion 20. The first cylindrical portion 34 and the nozzle portion 20 are spaced apart in the radial direction. The first cylindrical portion 34 covers the radially outer side of the nozzle portion 20. The tip of the first cylindrical portion 34 is arranged further proximal than the tip of the nozzle portion 20. In other words, the tip of the nozzle portion 20 protrudes distally relative to the tip of the first cylindrical portion 34.

[0035] As shown in FIG. 2 , the second medical instrument 122 is a puncture member 36. As shown in FIG. 4 , the puncture member 36 includes a connector 38, a puncture needle 40 provided at the tip of the connector 38, and an elastic body 42 provided in a hole 381 of the connector 38. The connector 38 is formed in a cylindrical shape having the hole 381. The connector 38 includes a second tubular portion 44 and a flange portion 46 provided at the tip of the second tubular portion 44. The inner circumferential surface of the second tubular portion 44 tapers toward the tip. The inclination angle of the taper of the inner circumferential surface of the second tubular portion 44 is greater than the inclination angle of the luer taper of the outer circumferential surface of the nozzle portion 20. Note that the inner circumferential surface of the second tubular portion 44 may be luer tapered like the outer circumferential surface of the nozzle portion 20. The hole 381 penetrates the second tubular portion 44 and the flange portion 46 in the axial direction of the connector 38. When the first medical instrument 121 and the second medical instrument 122 are connected, the nozzle portion 20 of the syringe 16 is inserted into and accommodated in the hole 381 from the base end of the second cylindrical portion 44. The flange portion 46 has a disk shape that extends radially outward.

[0036] The puncture needle 40 is held by a needle hub 48. The needle hub 48 includes a needle holding portion 50 and a disk-shaped base portion 52 formed at the tip of the needle holding portion 50. The needle holding portion 50 is inserted into and held in a hole 381 from the tip of the second cylindrical portion 44. The center of the needle holding portion 50 holds the puncture needle 40. The base end of the puncture needle 40 protrudes in the proximal direction from the base end of the needle hub 48 and is disposed in the hole 381 of the connector 38. The tip of the puncture needle 40 protrudes in the distal direction from the tip of the base portion 52. The base portion 52 is disposed in the distal direction of the flange portion 46 of the connector 38. The base portion 52 and flange 46 are disposed in abutting contact with each other. The puncture needle 40 is disposed in the center of the base portion 52. The tip of the puncture needle 40 is exposed to the outside relative to the base portion 52. The distal end surface of the base portion 52 has annular ribs 54 that protrude toward the distal end. The ribs 54 are arranged radially outward at a distance from the puncture needle 40. The ribs 54 protrude toward the distal end from the distal end surface of the base portion 52. The distal end of the puncture needle 40 protrudes further toward the distal end than the tip of the ribs 54. As shown in FIG. 1 , the outer peripheral surface of the base portion 52 has protrusions 55 that protrude radially outward.

[0037] As shown in Fig. 4, the elastic body 42 is made of an elastic material such as rubber. The elastic body 42 is disposed in the hole 381 of the connector 38. When the syringe 16 (first medical device 121) and the puncture member 36 (second medical device 122) are connected, the elastic body 42 is disposed in the hole 381 between the nozzle portion 20 and the needle holding portion 50 of the needle hub 48. The base end of the puncture needle 40 is inserted into the center of the elastic body 42. The elastic body 42 provides a liquid-tight seal between the hole 381 of the connector 38 and the needle holding portion 50.

[0038] When the first medical instrument 121 and the second medical instrument 122 are connected, the nozzle portion 20 of the syringe 16 is inserted into the hole 381 of the second cylindrical portion 44, and the elastic body 42 is pushed in the distal direction (axial direction) by the tip of the nozzle portion 20. When pushed in the distal direction by the nozzle portion 20, the elastic body 42 is compressed and elastically deformed so as to expand radially outward. The elastic body 42 comes into close contact with the inner circumferential surface of the hole 381.

[0039] As shown in FIG. 5 , the puncture member 36 is housed in a case 56 before use. The medical device 10A is made up of a puncture needle package P containing the puncture needle 40 and a syringe 16 to which the puncture member 36 is connected. The puncture needle package P includes the puncture member 36 and a case 56 capable of housing the puncture member 36. The case 56 has a case body 58 and a lid 60 that is openably attached to an opening 581 of the case body 58. The case body 58 is cylindrical with the opening 581 at one end. The case body 58 includes a housing space 62 that houses the puncture member 36. The case body 58 has the opening 581 formed at one end and a bottom 582 at the other end opposite the one end. When the puncture member 36 is housed in the housing space 62 of the case body 58 , the base portion 52 of the needle hub 48 faces the bottom portion 582 , and the proximal end of the connector 38 faces the opening 581 .

[0040] The case body 58 has a plurality of holding portions 64 that protrude radially inward from the inner circumferential surface of the case body 58. The base portion 52 of the puncture member 36 is placed and held on the proximal ends of the plurality of holding portions 64. At this time, the tip of the puncture needle 40 is positioned away from the bottom portion 582 of the case body 58. The puncture member 36 is housed in the housing space 62 in a state where its relative rotation with respect to the case body 58 is restricted. The inner circumferential surface of the case body 58 has a recess 583 that is recessed radially outward. The protrusion 55 of the needle hub 48 engages with the recess 583. Engagement of the protrusion 55 with the recess 583 prevents rotation of the puncture member 36 with respect to the case 56. Note that the anti-rotation mechanism of the needle hub 48 is not limited to a configuration in which the protrusion 55 of the needle hub 48 engages with the recess 583 of the case 56. For example, the inner circumferential surface of the case 56 may not have the recess 583, and the protrusion 55 of the needle hub 48 may be lightly press-fitted into the inner circumferential surface of the case 56. The tip of the protrusion 55 comes into contact with the inner circumferential surface of the case 56, and the frictional force between them prevents rotation of the puncture member 36. In this case, when a rotational force equal to or greater than a predetermined torque is applied to the puncture member 36, the frictional force exceeds the frictional force between the inner circumferential surface of the case 56 and the protrusion 55, causing the puncture member 36 to rotate relative to the case 56.

[0041] The lid 60 is made of a resin material such as polyethylene resin. The lid 60 is in the form of a flexible, thin sheet. The lid 60 is, for example, fused to the other end of the case body 58. The lid 60 closes the opening 581. The lid 60 covers the opening 581 of the case body 58, thereby sealing the storage space 62 of the case body 58. When connecting the puncture member 36 to the syringe 16, the user peels the lid 60 off the case body 58 to open the opening 581 (see FIG. 7 ). At this time, the base end of the connector 38 of the puncture member 36 is housed facing the opening 581.

[0042] As shown in FIG. 4 , the connection structure 14 includes a first screw portion 661 provided on the first medical device 121 and a second screw portion 662 provided on the second medical device 122 and threadedly engaged with the first screw portion 661. The first screw portion 661 is a tapered thread having a first thread 681. The first screw portion 661 is provided on the inner circumferential surface of the first cylindrical portion 34 of the locking portion 22 of the syringe 16. As shown in FIG. 6A , the first thread 681 has a first engaging surface 701A and a first non-engaging surface 701B. The first engaging surface 701A is inclined at a first angle θ11 with respect to a radial direction perpendicular to the axis of the syringe 16. The first angle θ11 is, for example, 1° to 24°. The first angle θ11 is more preferably, for example, 5° to 20°. Alternatively, the first angle θ11 is, for example, 10° or 24°. In the axial direction of the first medical instrument 121, the first non-engaging surface 701B is arranged on the opposite side of each first thread 681 from the first engaging surface 701A.

[0043] As shown in FIG. 4 , the second screw portion 662 is a tapered thread having a second thread 682. The second screw portion 662 is provided on the connector 38 of the puncture member 36. The second screw portion 662 is provided on the outer peripheral surface of the second tubular portion 44 of the connector 38. As shown in FIG. 6A , the second screw thread 682 has a second meshing surface 702A and a second non-meshing surface 702B. The second meshing surface 702A is inclined at a second angle θ21 with respect to a radial direction perpendicular to the axis of the puncture member 36. The second angle θ21 is, for example, 25°. In the axial direction of the puncture member 36, the second non-meshing surface 702B is located on the opposite side of each second screw thread 682 from the second meshing surface 702A.

[0044] When the first threaded portion 661 and the second threaded portion 662 are threaded together, a first mating surface 701A of the first threaded portion 661 and a second mating surface 702A of the second threaded portion 662 come into contact at a first region S1 in the connection direction of the first medical device 121 and the second medical device 122. When the first threaded portion 661 and the second threaded portion 662 are threaded together, a first non-mating surface 701B of the first thread 681 of the first threaded portion 661 and a second non-mating surface 702B of the second thread 682 of the second threaded portion 662 are positioned at a second region S2 provided on the opposite side from the first region S1 in the connection direction of the first medical device 121 and the second medical device 122. At the second region S2, the first non-mating surface 701B and the second non-mating surface 702B are not in contact with each other. The first portion S1 is a portion where the first meshing surface 701A and the second meshing surface 702A contact each other in the connection direction (the up-and-down direction in FIG. 4 ) of the first medical device 121 and the second medical device 122. In the first portion S1, the first angle θ11 of the first meshing surface 701A of the first thread 681 and the second angle θ21 of the second meshing surface 702A of the second thread 682 are different.

[0045] Specifically, at the first region S1, the first angle θ11 of the first meshing surface 701A of the first thread portion 661 is smaller than the second angle θ21 of the second meshing surface 702A of the second thread portion 662 (θ11<θ21). The angle θ12 of the first non-meshing surface 701B of the first thread 681 at the second region S2 (hereinafter referred to as the third angle θ12) is larger than the first angle θ11 of the first meshing surface 701A of the first thread 681 at the first region S1. Note that the third angle θ12 of the first non-meshing surface 701B of the first thread 681 at the second region S2 may be the same as the first angle θ11 of the first meshing surface 701A of the first thread 681 at the first region S1.

[0046] For example, the difference between the first angle θ11 of the first meshing surface 701A of the first thread portion 661 and the second angle θ21 of the second meshing surface 702A of the second thread portion 662 is less than 25° (θ21 - θ11 < 25°). Note that the difference between the first angle θ11 of the first meshing surface 701A and the second angle θ21 of the second meshing surface 702A is not particularly limited as long as it is less than 25°. For example, the upper limit of the difference between the first angle θ11 of the first meshing surface 701A and the second angle θ21 of the second meshing surface 702A may be 24°, 22°, 20°, 18°, or 15°. The lower limit of the difference between the first angle θ11 of the first meshing surface 701A and the second angle θ21 of the second meshing surface 702A is not particularly limited as long as it is 0° or greater. For example, the lower limit of the difference between the first angle θ11 of the first mating surface 701A and the second angle θ21 of the second mating surface 702A may be 2°, 5°, 8°, or 10°.

[0047] Note that, in the first region S1, the first angle θ11 of the first meshing surface 701A of the first thread portion 661 is not limited to being smaller than the second angle θ21 of the second meshing surface 702A of the second thread portion 662. As shown in Fig. 6B , for example, in the first region S1, the second angle θ21 of the second meshing surface 702A of the second thread portion 662 may be smaller than the first angle θ11 of the first meshing surface 701A of the first thread portion 661 (θ21 < θ11). That is, it is only necessary that the first angle θ11 of the first meshing surface 701A and the second angle θ21 of the second meshing surface 702A in the first region S1 are different from each other. In this case, the angle θ22 of the second non-meshing surface 702B of the second thread 682 at the second portion S2 (hereinafter referred to as the fourth angle θ22) is greater than the second angle θ21 of the second meshing surface 702A of the second thread 682 at the first portion S1. Note that the fourth angle θ22 of the second non-meshing surface 702B at the second portion S2 and the second angle θ21 of the second meshing surface 702A at the first portion S1 may be the same.

[0048] 1 , a syringe 16, which is a first medical device 121, and a puncture member 36, which is a second medical device 122, are connected to each other by a connection structure 14 to form a syringe assembly 10B, which is a medical device 10. Note that the present invention is not limited to a case in which the syringe 16, which is the first medical device 121, and the puncture member 36, which is the second medical device 122, are connected to each other by the connection structure 14. For example, a first medical device other than the syringe 16 and a second medical device other than the puncture member 36 may be connected to each other by the connection structure 14 to form a medical device 10 other than the syringe assembly 10B.

[0049] Next, a case where the first medical instrument 121 and the second medical instrument 122 are connected to assemble the syringe assembly 10B, which is the medical instrument 10, will be described.

[0050] As shown in FIG. 7, the user peels off the lid 60 of the puncture needle package P to expose the opening 581 of the case body 58 .

[0051] The tip of the syringe 16 is inserted into the accommodation space 62 of the case body 58, and the nozzle portion 20 is inserted into the connector 38. With the case body 58 fixed, the syringe 16 is moved toward the tip while rotating relative to the case body 58. The first threaded portion 661 of the first cylindrical portion 34 and the second threaded portion 662 of the second cylindrical portion 44 are threaded together. At this time, the puncturing member 36 is prevented from rotating relative to the case body 58, so the puncturing member 36 does not rotate within the accommodation space 62.

[0052] In the connection direction between the syringe 16 and the puncture member 36, the first meshing surface 701A of the first screw portion 661 and the second meshing surface 702A of the second screw portion 662 come into contact at the first position S1, as shown in Fig. 6A . When the syringe 16 is further rotated and moved toward the distal end relative to the case body 58, the elastic body 42 is pushed toward the distal end by the tip of the nozzle portion 20, as shown in Fig. 4 . The base end of the puncture needle 40 is inserted into the flow path 201 of the nozzle portion 20.

[0053] As a result, the first screw portion 661 of the syringe 16 and the second screw portion 662 of the puncture member 36 are screwed together, thereby connecting the first medical device 121 (syringe 16) and the second medical device 122 (puncture member 36).

[0054] After assembling the medical device 10 in which the puncture member 36 is connected to the tip of the syringe 16 by the connecting structure 14, the puncture member 36 connected to the syringe 16 is removed from the case 56 of the puncture needle package P. This completes the assembly of the syringe assembly 10B, which is the medical device 10.

[0055] When the first mating surface 701A of the first threaded portion 661 and the second mating surface 702A of the second threaded portion 662 contact each other at the first site S1, the first angle θ11 of the first mating surface 701A is smaller than the second angle θ21 of the second mating surface 702A. Therefore, when assembling the syringe assembly 10B, the first mating surface 701A and the second mating surface 702A do not come into surface contact with each other, and the corner of the first thread 681 of the first threaded portion 661 contacts a part of the second mating surface 702A. As a result, the corner of the apex of the first thread 681 bites into the second mating surface 702A, thereby firmly connecting the first medical device 121 (syringe 16) and the second medical device 122 (puncture member 36) by the connecting structure 14. If the user rotates the syringe 16 more than necessary and a torque equal to or greater than a predetermined value is applied to the puncturing member 36 via the syringe 16, the convex portion 55 of the puncturing member 36 will disengage from the concave portion 583 of the case 56 while the connection between the syringe 16 and the puncturing member 36 is maintained. This causes the puncturing member 36 to rotate relative to the case main body 58 while the connection between the syringe 16 and the puncturing member 36 is maintained. In other words, before the first screw portion 661 and the second screw portion 662 are unthreaded from each other, the fixed state of the puncturing member 36 relative to the case main body 58 is released, and the puncturing member 36 will spin freely.

[0056] Next, we will explain the test conducted to confirm the relationship between the torque applied during connection and the first thread 681 of the first screw portion 661 when connecting the first medical device 121 and the second medical device 122 using the connection structure 14.

[0057] [Test Method] First, the syringe 16 having the first threaded portion 661 is fixed to a digital torque gauge (manufactured by Imada Co., Ltd., product name: Handy Type Torque Meter HTG2-P Series, model number: HTG2-5N-P), and then the puncture member 36 having the second threaded portion 662 is fixed inside the case body 58 with an adhesive or the like. This prevents the puncture member 36 from spinning freely inside the case body 58. The case body 58 is set on a fixing block (not shown).

[0058] The syringe 16 and the puncture member 36 are connected to each other by threading the first threaded portion 661 of the syringe 16, which is fixed to a digital torque gauge, into the second threaded portion 662 of the puncture member 36. The puncture member 36 is then rotated relative to the syringe 16 via the fixing block. The puncture member 36 is rotated until the threaded portion between the first threaded portion 661 and the second threaded portion 662 is broken, or until the first threaded portion 661 and the second threaded portion 662 move relative to each other in the radial direction, disengaging from the first threaded portion 661 and the second threaded portion 662 and allowing the puncture member 36 to spin freely, and the maximum torque value is measured using the digital torque gauge. The above test is performed multiple times using syringes 16 with different first angles θ11 of the first threaded portion 661.

[0059] 8 , which shows the relationship between the torque applied when connecting the syringe 16 and the puncture member 36 and the first angle θ11 of the first meshing surface 701A of the first thread 681 of the first screw portion 661, when the torque is 1.00 when the first angle θ11 of the first meshing surface 701A is 25°, the torque increase rate when the first angle θ11 is 15° is 1.03 compared to when the first angle θ11 is 25°, and the torque increase rate when the first angle θ11 is 5° is 1.06 compared to when the first angle θ11 is 25°. The torque increase rate is the rate of increase in torque relative to the torque when the first angle θ11 of the first meshing surface 701A is 25°. From the above, it was found that the torque that can be applied when connecting the syringe 16 and the puncture member 36 increases as the first angle θ11 of the first meshing surface 701A of the first thread portion 661 in the syringe 16 decreases. In other words, it was found that by reducing the first angle θ11 of the first meshing surface 701A, the syringe 16 having the first thread portion 661 and the puncture member 36 having the second thread portion 662 can be more firmly connected.

[0060] Next, administration of the medicinal liquid M to the patient 300 using the syringe assembly 10B will be described.

[0061] 9 , when base portion 52 of puncture member 36 is pressed against skin 302 of patient 300, ribs 54 press a portion of skin 302 inside ribs 54. Inside ribs 54, skin 302 bulges toward base portion 52, and the tip of puncture needle 40 punctures the center of bulging skin 302. After confirming that puncture needle 40 has punctured skin 302, the user presses the base end of plunger 32 toward the tip, causing gasket 28 to compress medicinal solution M toward the tip. Medicinal solution M in chamber 30 passes through flow path 201 of nozzle portion 20 and the lumen of puncture needle 40, and is administered subcutaneously from the tip.

[0062] This embodiment has the following advantages.

[0063] 4 , the medical device 10 includes a first medical device 121 having a first threaded portion 661 and a second medical device 122 having a second threaded portion 662 that is threaded onto the first threaded portion 661, and has a first region S1 where a first meshing surface 701A of the first thread 681 and a second meshing surface 702A of the second thread 682 come into contact with each other when the first threaded portion 661 and the second threaded portion 662 are threaded together. At the first region S1, a first angle θ11 of the first meshing surface 701A of the first thread 681 of the first threaded portion 661 is different from a second angle θ21 of the second meshing surface 702A of the second thread 682 of the second threaded portion 662.

[0064] As a result, when the first threaded portion 661 and the second threaded portion 662 are screwed together, the first meshing surface 701A and the second meshing surface 702A, which have different angles (first angle θ11, second angle θ21) from each other, do not come into surface contact at the first site S1. Therefore, when the first threaded portion 661 and the second threaded portion 662 are screwed together, the first threaded portion 661 and the second threaded portion 662 are effectively prevented from moving relative to each other in the radial direction along the first meshing surface 701A and the second meshing surface 702A and riding up. This allows the first threaded portion 661 and the second threaded portion 662 to be firmly connected.

[0065] 4 , the first medical instrument 121 is a syringe 16 including a locking portion 22 surrounding a nozzle portion 20, and the second medical instrument 122 is a puncturing member 36 including a connector 38 having a hole 381 capable of accommodating the nozzle portion 20 and a puncturing needle 40 provided at the tip of the connector 38. The locking portion 22 includes a first cylindrical portion 34 having a first threaded portion 661 on its inner circumferential surface, and the connector 38 includes a second cylindrical portion 44 having a second threaded portion 662 on its outer circumferential surface. This firmly connects the first threaded portion 661 of the first cylindrical portion 34 and the second threaded portion 662 of the second cylindrical portion 44, thereby effectively suppressing leakage of the medicinal solution M when the medical instrument 10, in which the syringe 16 and the puncturing member 36 are connected, administers the medicinal solution.

[0066] 6A , a first angle θ11 of a first mating surface 701A of a first thread 681 of a first screw portion 661 is smaller than a second angle θ21 of a second mating surface 702A of a second thread 682 of a second screw portion 662. As a result, when the first screw portion 661 and the second screw portion 662 are screwed together, the first thread 681 of the first screw portion 661 bites into the second mating surface 702A of the second thread 682 of the second screw portion 662, thereby firmly connecting the first medical device 121 and the second medical device 122.

[0067] 6B , the second angle θ21 of the second meshing surface 702A of the second thread 682 of the second screw portion 662 is smaller than the first angle θ11 of the first meshing surface 701A of the first thread 681 of the first screw portion 661. As a result, when the first screw portion 661 and the second screw portion 662 are screwed together, the second thread 682 of the second screw portion 662 bites into the first meshing surface 701A of the first screw portion 661, thereby firmly connecting the first medical device 121 and the second medical device 122.

[0068] 4 , the puncture member 36 includes an elastic body 42 that is disposed in the hole 381 of the connector 38 and is pressed and compressed by the tip of the nozzle portion 20 when the syringe 16 is connected. As a result, when the syringe 16 and the puncture member 36 are connected by the connection structure 14, the elastic body 42 is compressed by the tip of the nozzle portion 20, and the elastic body 42 can effectively prevent leakage of the medicinal solution M through between the tip of the syringe 16 and the hole 381 of the puncture member 36. Even if the syringe 16 and the puncture member 36 are urged in directions away from each other by the elastic force, the first screw thread 681 and the second screw thread 682 are effectively prevented from riding over each other in the radial direction.

[0069] As shown in FIG. 6A , the medical device has a second portion S2 located on the opposite side of the first portion S1 in the connection direction of the first medical device 121 and the second medical device 122, and the third angle θ12 of the first non-engaging surface 701B of the first thread 681 at the second portion S2 is greater than the first angle θ11 of the first engaging surface 701A of the first thread 681 at the first portion S1. This allows the third angle θ12 of the first non-meshing surface 701B of the first thread 681 in the second portion S2 to be set to the same as the second angle θ21 of the second meshing surface 702A of the second thread 682, so the first screw portion 661 can be formed more easily and at lower cost than a configuration in which the first angle θ11 of the first meshing surface 701A of the first thread 681 in the first and second portions S1, S2 and the third angle θ12 of the first non-meshing surface 701B are all smaller than the second angle θ21 of the second meshing surface 702A of the second thread 682.

[0070] 6B , when the first threaded portion 661 and the second threaded portion 662 are threaded together, the second threaded portion 662 has a second portion S2 provided on the opposite side to the first portion S1 in the connection direction of the first medical device 121 and the second medical device 122, and the fourth angle θ22 of the second non-meshing surface 702B of the second thread 682 at the second portion S2 is larger than the second angle θ21 of the second meshing surface 702A of the second thread 682 at the first portion S1. This allows the fourth angle θ22 of the second non-meshing surface 702B of the second thread 682 at the second portion S2 to be set to the same as the first angle θ11 of the first meshing surface 701A of the first thread 681. Therefore, the second screw portion 662 can be formed more easily and at lower cost than in a configuration in which the second angle θ21 of the second meshing surface 702A of the second thread 682 of the first and second portions S1 and S2 and the fourth angle θ22 of the second non-meshing surface 702B are both smaller than the first angle θ11 of the first meshing surface 701A of the first thread 681.

[0071] 6A , the difference between the first angle θ11 of the first mating surface 701A of the first threaded portion 661 and the second angle θ21 of the second mating surface 702A of the second threaded portion 662 is less than 25°, which allows the first medical device 121 and the second medical device 122 to be connected more firmly.

[0072] 1, the syringe assembly 10B includes the syringe 16 and the puncture member 36. This allows the syringe 16 and the puncture member 36 that constitute the syringe assembly 10B to be firmly connected to each other.

[0073] 7 , the device includes a syringe 16, a puncture member 36, and a case 56 that houses and holds the puncture member 36. When the puncture member 36 and the syringe 16 are connected by the first screw portion 661 and the second screw portion 662 with the puncture member 36 held inside the case 56, the puncture member 36 rotates relative to the case 56 when a torque equal to or greater than a predetermined value is applied to the puncture member 36 as the first screw portion 661 and the second screw portion 662 are threaded together.

[0074] As a result, even if a torque greater than a predetermined level is applied to the puncturing member 36, causing the puncturing member 36 and the case 56 to rotate relative to each other, the engagement between the first screw portion 661 and the second screw portion 662 is strong, so the engagement between the first screw portion 661 and the second screw portion 662 is effectively maintained.

[0075] The present invention is not limited to the above disclosure, and various configurations can be adopted without departing from the gist of the present invention.

Claims

1. A connection structure for medical devices that connects a first medical device having a first threaded portion to a second medical device having a second threaded portion that is threaded onto the first threaded portion, wherein the first threaded portion of the first medical device is a tapered thread having a first thread, and the second threaded portion of the second medical device is a tapered thread having a second thread that contacts the first thread of the first threaded portion, and when the first threaded portion and the second threaded portion are threaded together, a first portion is formed where a first engagement surface of the first thread and a second engagement surface of the second thread contact each other, the first engagement surface is inclined at a first angle with respect to a direction perpendicular to the axis of the first medical device, and the second engagement surface is inclined at a second angle with respect to a direction perpendicular to the axis of the second medical device, and at the first portion, the first angle of the first engagement surface of the first thread and the second angle of the second engagement surface of the second thread are different.

2. A connection structure for medical instruments as described in claim 1, wherein the first medical instrument is a syringe having a main body capable of being filled with a medicinal liquid, a nozzle provided at the tip of the main body, and a locking portion surrounding the nozzle; the second medical instrument is a puncture member having a connector with a hole capable of accommodating the nozzle, and a puncture needle provided at the tip of the connector; the locking portion comprises a first tubular portion having the first screw portion on its inner surface, and the connector comprises a second tubular portion having the second screw portion on its outer surface.

3. A connection structure for medical devices according to claim 2, wherein the first angle of the first engagement surface of the first threaded portion is smaller than the second angle of the second engagement surface of the second threaded portion.

4. A connection structure for a medical device according to claim 2, wherein the second angle of the second engagement surface of the second threaded portion is smaller than the first angle of the first engagement surface of the first threaded portion.

5. A connection structure for a medical device according to claim 2, wherein the puncture member is provided with an elastic body that is disposed in the hole of the connector and is pressed and compressed by the tip of the nozzle when the syringe is connected.

6. A connection structure for medical devices as described in claim 3, which has a second portion provided on the opposite side of the first portion in the connection direction of the first medical device and the second medical device when the first threaded portion and the second threaded portion are screwed together, and wherein the angle of the first non-engaging surface of the first thread in the second portion is greater than the first angle of the first engaging surface of the first thread in the first portion.

7. A connection structure for medical devices as described in claim 4, which has a second portion provided on the opposite side of the first portion in the connection direction of the first medical device and the second medical device when the first threaded portion and the second threaded portion are screwed together, and the angle of the second non-engaging surface of the second thread in the second portion is larger than the second angle of the second engaging surface of the second thread in the first portion.

8. A connection structure for a medical device according to claim 1, wherein the difference between the first angle of the first engagement surface of the first threaded portion and the second angle of the second engagement surface of the second threaded portion is less than 25°.

9. A syringe assembly comprising the connection structure for a medical device according to claim 2, comprising the syringe and the piercing member.

10. A medical device comprising the syringe assembly of claim 9, comprising the syringe, the puncture member, and a case in which the puncture member is housed and held, wherein the puncture member and the syringe can be connected by the first screw portion and the second screw portion with the puncture member held inside the case, and when the syringe and the puncture member are connected, the puncture member rotates relative to the case when a torque equal to or greater than a predetermined value is applied to the puncture member as the first screw portion and the second screw portion are threaded together.

Images