Indwelling needle assembly

Abstract

Provided is an indwelling needle assembly that has excellent manipulability. An indwelling needle assembly 1 comprises a tubular outer needle 10, an outer needle base 20 to which a base end of the outer needle 10 is fixed, an inner needle 30 which is inserted into the outer needle 10 and the outer needle base 20, and a casing 50 which holds the inner needle 30 and removably holds the outer needle base 20 at one end thereof, wherein the casing 50 includes a holding part 51 that is held by a user, and an extended part 53 that is formed so as to extend from the holding part 51 in the axial direction of the inner needle 30 and that holds the outer needle base 20 at the distal end, the extended part 53 having, on the outer circumferential surface, a stopper 53d that positions the outer needle base 20 in the axial direction of the inner needle 30, the stopper 53d being configured so as to partially project in the circumferential direction of the inner needle 30 or being configured such that the amount of projection changes in the circumferential direction of the inner needle 30.

Description

[Technical field]

[0001] The present invention relates to an indwelling needle assembly including an indwelling needle that is inserted into a blood vessel or the like and is used for connecting to an infusion line or the like. [Background technology]

[0002] Conventionally, there has been known an indwelling needle in which an inner needle is inserted into an outer needle (catheter) in advance, and the outer needle is inserted into a blood vessel or the like of a living body by being guided by the inner needle, and then the inner needle is removed, and an infusion line or the like is connected to the indwelling outer needle. In recent years, indwelling needle assemblies that make it possible to house the inner needle in a housing by a coil spring or the like after removal have become widespread, in order to prevent viral infections and the like caused by touching the inner needle after removal (see, for example, Patent Document 1).

[0003] In such an indwelling needle, the sharp tip of the inner needle protruding from the tip of the outer needle is inserted into the living body to reach the inside of a blood vessel, etc., and then only the outer needle is pushed further along the inner needle to insert the tip of the outer needle deep inside the blood vessel, etc. An outer needle base (catheter hub) equipped with a luer connector for connecting an infusion line, etc., is fixed to the base end of the outer needle, and the operation of pushing the outer needle along the inner needle is generally performed by pressing this outer needle base with a finger.

[0004] More specifically, the outer needle base is usually held in engagement with one end of the housing that contains the inner needle after it has been removed, so that the user can, for example, hold the housing with their thumb and middle finger and press the outer needle base with their index finger to release the engagement with the housing and push only the outer needle into a blood vessel, etc. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2007-296022 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the indwelling needle assembly described in Patent Document 1 has a problem that it is difficult to press the outer needle base with the index finger. Specifically, since the outer needle base is generally configured to have a shape that reduces in diameter toward the outer needle side, it is necessary to press the opening side end face on the opposite side of the outer needle to release the engagement between the outer needle base and the housing and push the outer needle into the inside of a blood vessel, etc. However, in the indwelling needle assembly described in Patent Document 1, one end of the housing is configured as a stepped cylinder, and the small diameter part of the stepped cylinder is inserted into the opening of the outer needle base to engage with it, and the opening side end face of the outer needle base is abutted against the stepped part to position the outer needle base in the axial direction, so that most of the opening side end face is hidden by the large diameter part of the stepped cylinder, and the area that can be pressed with a fingertip is narrowed.

[0007] For this reason, depending on the level of proficiency of the user, such as a doctor or nurse, it may be difficult to operate the device with only one hand, and it may be necessary to, for example, hold the housing in the right hand and pinch the outer needle base with the thumb and index finger of the left hand to push it forward.

[0008] In view of the above circumstances, the present invention aims to provide an indwelling needle assembly that is easy to operate. [Means for solving the problem]

[0009] The indwelling needle assembly according to the present invention comprises a tubular outer needle, an outer needle base to which a base end of the outer needle is fixed, an inner needle inserted into the outer needle and the outer needle base, and a casing that holds the inner needle and detachably holds the outer needle base at one end thereof, the casing having a grip portion that is held by a user, and an extension portion that is provided so as to extend from the grip portion in the axial direction of the inner needle and holds the outer needle base at its tip, the extension portion having a stopper on its outer peripheral surface that positions the outer needle base in the axial direction of the inner needle, the stopper being configured to partially protrude in the circumferential direction of the inner needle, or being configured so that the amount of protrusion varies in the circumferential direction of the inner needle. the inner needle base is arranged in the housing to be movable in the axial direction of the inner needle with a base end of the inner needle fixed thereto; a biasing member that biases the inner needle base toward the other end of the housing; and a switch member that is arranged in the housing to be movable between a restricting position that restricts the movement of the inner needle base and a releasing position that releases the restriction on the movement of the inner needle base, the switch member being arranged on the extension side of the grip portion and having an exposed portion that is exposed from the grip portion. , The exposed portion is configured to have a shape in which the top surface on the extension side has an inclined surface that gradually approaches the gripping portion toward the extension side, and the gripping portion or the extension portion has an auxiliary inclined surface between the exposed portion and the outer needle base that is inclined in the same inclination direction as the inclined surface. It is characterized by the above.

[0010] According to the present invention, the difference in outer diameter between the outer needle base and the extending portion can be made large in the portion other than the stopper, which makes it easier to press the outer needle base. Therefore, the user can easily push the outer needle base along the inner needle with the index finger while holding the gripping portion with the thumb and middle finger, thereby improving the operability of the indwelling needle assembly. In addition, when trying to press the outer needle base with the index finger, it is necessary to push it forward while being careful not to press the switch for storing the inner needle with the index finger until the pressing of the outer needle base is finished, but by configuring the exposed part to have a shape in which the top surface on the extension side has an inclined surface that gradually approaches the gripping part toward the extension side, it is possible to push the outer needle base without touching the switch member while providing a mechanism for easily storing the inner needle in the housing after removal by pressing the switch member, thereby improving operability. Furthermore, by configuring it to have an auxiliary inclined surface inclined in the same inclination direction as the inclined surface between the exposed part and the outer needle base, it is possible to push the outer needle base with the finger extended almost straight without being hindered by the gripping part or the extension part, making it easier to press the outer needle base and ensuring the effect of the inclined surface regardless of the shape of the gripping part or the extension part.

[0011] In the present invention, the stopper is preferably configured in the form of a rib that is continuous in the axial direction of the inner needle.

[0012] According to this, since it is possible to secure the strength and rigidity of the extension part by using the stopper as a reinforcing member, the extension part can be made smaller in diameter. Therefore, the difference in outer diameter between the outer needle base and the extension part can be made larger in the part other than the stopper, and the outer needle base can be more easily pressed.

[0013] In addition, in the present invention, it is preferable that the stopper is configured to protrude only at the portions of the inner needle and the outer needle that are to be punctured, or that the amount of protrusion of the portions that are to be punctured is greater than that of other portions.

[0014] This makes it possible to provide a stopper only in a portion where the fingers pressing the outer needle base are not normally placed, or to reduce the amount of protrusion of the stopper in the portion where the fingers pressing the outer needle base are normally placed, thereby preventing the operation of pressing the outer needle base from being hindered by the stopper.

[0015] Also in the present invention, when trying to press the outer needle base with the index finger, it is necessary to proceed while being careful not to press the switch for storing the inner needle with the index finger until the outer needle base has been pressed. Effect of the Invention

[0020] The indwelling needle assembly according to the present invention can provide the excellent effect of improving operability. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a partially exploded external perspective view of an indwelling needle assembly according to an embodiment of the present invention. [Diagram 2] 2 is a cross-sectional view taken along line II in FIG. [Diagram 3] FIG. [Figure 4] FIG. 3 is a cross-sectional view taken along line II-II in FIG. [Diagram 5] FIG. 11 is a cross-sectional view showing a state in which the inner needle is housed in the housing. [Figure 6] FIG. 11 is a cross-sectional view showing a modified example of the switch member. [Figure 7] FIG. [Figure 8] FIG. 4 is an external perspective view showing a part of the tip side of the base member. [Figure 9] FIG. 2 is a schematic diagram showing a state in which the indwelling needle assembly is used. [Figure 10] FIG. 13 is a diagram showing a modified example of the inner needle base. [Figure 11] FIG. 13 is a diagram showing a modified example of the inner needle base. [Figure 12] FIG. 13 is a diagram showing a modified example of the housing. [Figure 13] FIG. 13 is a diagram showing a modified example of the housing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1 is an external perspective view showing a part of an indwelling needle assembly 1 according to one embodiment of the present invention in an exploded form. Fig. 2A is a cross-sectional view taken along line II in Fig. 1, and Fig. 2B is a cross-sectional view showing an enlarged part of Fig. 2A.

[0023] As shown in these figures, the indwelling needle assembly 1 comprises an outer needle (catheter) 10 which is inserted into a blood vessel or the like of a living body and left in place, an outer needle base (catheter hub) 20 fixed to the base end of the outer needle 10, an inner needle 30 inserted into the outer needle 10 and the outer needle base 20, an inner needle base 40 fixed to the base end of the inner needle 30, a casing 50 which holds the outer needle base 20 at one end and houses the inner needle base 40 so as to be movable in the axial direction of the inner needle 30, a biasing member 60 arranged in the casing 50 so as to cover the outer periphery of the inner needle base 40, and a switch member 70 arranged in the casing 50 so as to be movable in a direction perpendicular to the axial direction of the inner needle 30.

[0024] The indwelling needle assembly 1 also includes a protector 80 that is attached to the housing 50 so as to cover the outer needle 10, the outer needle base 20, the inner needle 30, a part of the housing 50, and the switch member 70, and is removed when in use. Note that Figures 1 and 2B show a state in which the protector 80 has been removed, and Figure 2A shows a state in which the protector 80 has been attached to the housing 50.

[0025] The indwelling needle assembly 1 is configured based on the axial direction of the inner needle 30, and the axial direction of the entire indwelling needle assembly 1, the outer needle 10, the outer needle base 20, the inner needle 30, the inner needle base 40, the housing 50, and the protector 80 approximately coincides with the axial direction of the inner needle 30, and the same is true for the circumferential direction. Therefore, in the following description, the left-right direction in Figures 2A and B is the axial direction, the left side is the tip side, and the right side is the base side. Furthermore, the indwelling needle assembly 1 is usually used in a position where the lower side in Figure 1 and Figures 2A and B is the living body side, that is, the side to be punctured by the inner needle 30 and the outer needle 10.

[0026] The outer needle 10 is a tubular member with a tapered tip, and is made of an appropriate flexible resin. The outer needle base 20 is a cylindrical member with an outer shape of a stepped truncated cone for connecting an infusion line, a syringe, or the like to the outer needle 10, and is equipped with a luer connector of a predetermined standard. An outer needle fixing part 21 with reduced inner and outer diameters is provided at the tip of the outer needle base 20, and the base end of the outer needle 10 is fixed to this outer needle fixing part 21 with an adhesive or the like.

[0027] The outer needle 10 and the outer needle base 20 are made of a transparent or semi-transparent resin, and users such as doctors and nurses can check for so-called backflow (flashback) at the outer needle 10 and the outer needle base 20. Note that the outer needle base 20 may be provided with an appropriate hemostasis valve to prevent blood stored inside from leaking out after the outer needle base 20 is removed from the housing 50.

[0028] The inner needle 30 is a tubular member with a blade surface formed at its tip, and is made of a suitable metal or resin having higher rigidity than the outer needle 10. The shape of the tip of the inner needle 30 is not particularly limited, and the puncture resistance may be reduced by, for example, backcutting or lancet processing. A side hole 31 is provided near the tip of the inner needle 30 to allow backflow blood to flow into the gap between the inner needle 30 and the outer needle 10 and make it visible.

[0029] That is, a portion of the backflowing blood that flows from inside the blood vessel into the inner needle 30 flows into the gap between the inner needle 30 and the outer needle 10 through the side hole 31, and can be seen through the transparent or semi-transparent outer needle 10. The blood that passes between the inner needle 30 and the outer needle 10 is stored inside the outer needle base 20. The blood stored in the outer needle base 20 can also be seen through the transparent or semi-transparent outer needle base 20.

[0030] The inner needle base 40 is a substantially stepped cylindrical member for supporting the inner needle 30, and is composed of a small diameter portion 41 on the tip side and a large diameter portion 42 on the base side. Anti-rotation protrusions 41a are provided in two locations on the outer circumferential surface on the base side of the small diameter portion 41 to prevent relative rotation between the inner needle base 40 and the housing 50. Also, an inner needle fixing portion 41b with a reduced inner diameter is provided on the tip side of the small diameter portion 41.

[0031] The base end of the inner needle 30 inserted into the small diameter portion 41 is fixed by adhesive or the like at this inner needle fixing portion 41b. The inside of the inner needle 30 communicates with the inside of the inner needle base 40, and blood that passes through the inside of the inner needle 30 flows into the inside of the inner needle base 40. The inner needle base 40, together with the housing 50, is made of a transparent or semi-transparent resin, allowing the user to check for backflow of blood at the inner needle base 40 as well.

[0032] The opening on the base end side of the large diameter part 42 of the inner needle base 40 is closed by a filter 43 that has air permeability but no liquid permeability. As a result, the internal space of the inner needle base 40 forms a flash chamber that stores blood that has passed through the inner needle 30. The filter 43 is made of a porous body, and by appropriately discharging air from within the inner needle base 40, it promotes the flow of blood into the inner needle base 40 and prevents blood stored in the inner needle base 40 from leaking to the outside. The filter 43 is inserted into the large diameter part 42 from the base end side, and is positioned at a position slightly inward from the base end by abutting against a positioning protrusion 42a provided on the inside of the large diameter part 42.

[0033] The inner circumferential surface of the large diameter portion 42 on the base end side relative to the filter 43 is tapered toward the base end side to facilitate attachment of the filter 43 to the inner needle base 40 (insertion into the inner needle base 40). The inner circumferential surface on the base end side relative to the filter 43 forms a housing portion 44 that houses a part of the housing 50. Details of the housing portion 44 will be described later. A brim-shaped force receiving portion 45 that receives the biasing force of the biasing member 60 is provided on the outer circumferential surface of the base end side of the large diameter portion 42.

[0034] The housing 50 holds each part of the indwelling needle assembly 1 and is held by the user. The housing 50 is configured into a bottomed tubular shape with only the tip side open by combining a base member 50a and an inner needle housing member 50b. The axial length of the housing 50 is set to a length that allows the entire inner needle 30 removed from the outer needle 10 to be housed together with the inner needle base 40.

[0035] The base member 50a is a tubular member that is composed of a hollow, approximately square prism-shaped gripping portion 51, an approximately cylindrical connecting portion 52 extending from the base end side of the gripping portion 51, and an approximately funnel-shaped extending portion 53 extending from the tip side of the gripping portion 51, and has a through hole 54 with a circular cross section that penetrates in the axial direction. The base member 50a is composed of a transparent or semi-transparent resin, and as described above, backflow blood in the inner needle base 40 can be visually observed from the outside.

[0036] The grip portion 51 is a portion for a user to grip. The grip portion 51 is configured with an outer shape that assumes a holding manner in which, when gripped with the right hand, the thumb is placed on the left side surface 51a and the middle finger is placed on the right side surface 51b (so-called horizontal holding). Specifically, the left side surface 51a and the right side surface 51b are each configured in a concave shape that is gradually separated from each other toward the tip side so that it is easy to apply force when puncturing with the inner needle 30. In addition, the left side surface 51a and the right side surface 51b are provided with a plurality of anti-slip protrusions 51c.

[0037] The tip side of the upper surface 51d of the gripping portion 51 is provided with a recess 51e having a substantially rectangular prism shape and a slit 51h penetrating between a bottom surface 51f of the recess 51e and a lower surface 51g of the gripping portion 51. The switch member 70 described later is inserted into the recess 51e and the slit 51h. The region of the upper surface 51d on the base end side of the recess 51e is formed in a concave shape that gradually moves away from the lower surface 51g toward the tip side. This allows the indwelling needle assembly 1 to be held with the thumb placed on the upper surface 51d and the index finger placed on the lower surface 51g (so-called vertical holding).

[0038] Moreover, by configuring the grip portion 51 in a substantially square prism shape that can be used in both horizontal and vertical holding, it is possible to prevent the housing 50 from rolling when placed on a desk or the like. This eliminates the need to provide a separate protrusion or the like for preventing rolling on the housing 50, and allows the housing 50 to be configured in a shape that is easier to hold and convenient to use. In particular, in this embodiment, by configuring the tip sides of the left and right side surfaces 51a, 51b of the grip portion 51 to protrude outward, not only is the operability during puncturing improved as described above, but the roll prevention function is also improved.

[0039] The corners on the tip side of the grip part 51 are provided with roundness 51i. The base end part of the grip part 51 is configured so that the outer shape gradually changes from a square to a circle while smoothly protruding toward the base end side, and when combined with the inner needle housing member 50b, the end faces of the grip part 51 and the inner needle housing member 50b are in close contact with each other. The outer diameter of the base end part of the grip part 51 is approximately the same as the outer diameter of the tip end part of the inner needle housing member 50b. That is, the base end part of the grip part 51 is configured so that there is no step between it and the inner needle housing member 50b, and this gives the housing 50 a shape that is easy to hold during use.

[0040] The connecting part 52 is a part that is inserted into and fitted into the inner needle housing member 50b. The outer diameter of the connecting part 52 is set slightly smaller than the inner diameter of the inner needle housing member 50b. In addition, a circumferentially continuous anti-dislodgement protrusion 52a is provided at a position slightly toward the tip of the middle part of the connecting part 52.

[0041] The extending portion 53 is a portion that accommodates and holds a part of the inner needle base 40 therein, and also detachably holds the outer needle base 20 fitted to the tip portion. The extending portion 53 will be described in detail later.

[0042] The through hole 54 is composed of a first inner diameter portion 54a having an inner diameter slightly larger than the outer diameter of the small diameter portion 41 of the inner needle base 40, and a second inner diameter portion 54b having an inner diameter slightly larger than the outer diameter of the force receiving portion 45 of the inner needle base 40. The first inner diameter portion 54a is provided at the tip portion of the extension portion 53, and the other portion of the through hole 54 constitutes the second inner diameter portion 54b. In addition, anti-rotation grooves 54c for receiving the anti-rotation protrusions 41a of the inner needle base 40 are provided at two locations on the base end side of the first inner diameter portion 54a.

[0043] The inner needle base 40 is disposed in a state where the tip of the small diameter portion 41 projects from the extension portion 53 on the tip side of the through hole 54. Therefore, the small diameter portion 41 of the inner needle base 40 is supported by the first inner diameter portion 54a, and the force receiving portion 45 is supported by the second inner diameter portion 54b, and the inner needle base 40 is accommodated inside the base member 50a in a state where there is little rattle. In this state, the anti-rotation projection 41a is accommodated in the anti-rotation groove 54c, so that the inner needle base 40 does not rotate relative to the base member 50a.

[0044] The inner needle housing member 50b is a bottomed cylindrical member whose outer diameter decreases slightly toward the base end side and which has a bottom 55 on the base end side. A retaining groove 56 that continues in the circumferential direction is provided on the inner peripheral surface of the inner needle housing member 50b at a position corresponding to the retaining protrusion 52a of the connection portion 52 of the base member 50a. The retaining groove 56 engages with the retaining protrusion 52a to prevent the base member 50a and the inner needle housing member 50b from being easily separated.

[0045] Moreover, the inner needle housing member 50b is made of an appropriate resin, and the bottom 55 has a shape that protrudes (is recessed) inward due to the mold structure during resin molding. That is, the bottom 55 is a portion where the gate (the inlet of the resin flowing into the mold cavity) of the injection molding is disposed, and by recessing the bottom 55 so that the thickness is approximately constant, the occurrence of sink marks, voids, etc. is prevented, while the gate mark, which may become a sharp cut mark, does not protrude outward. By disposing the gate at the bottom 55, the flow of the resin in the cavity can be made smooth, and moldability can be improved. In addition, since there is no need to provide a recess or the like for preventing the gate mark from protruding on the outer peripheral surface that is likely to come into contact with the user of the indwelling needle assembly 1 or the living body to be punctured, the inner needle housing member 50b can be configured to have a shape that is easy to hold.

[0046] The biasing member 60, which is configured from a coil spring, biases the inner needle 30 after removal toward the base end side to retract it into the housing. The biasing member 60 is disposed in a state in which the large diameter portion 42 of the inner needle base 40 is inserted in the second inner diameter portion 54b of the through hole 54. Therefore, the biasing member 60 generates a biasing force by being compressed between the end face on the tip side of the second inner diameter portion 54b (the step portion with the first inner diameter portion 54a) and the force receiving portion 45 of the inner needle base 40, and biases the inner needle base 40 toward the base end side.

[0047] The tip end side of the second inner diameter portion 54b is configured to be gradually tapered toward the tip end side. This allows the biasing member 60 to be fitted into the second inner diameter portion 54b and held by the base member 50a during assembly, improving ease of assembly.

[0048] The switch member 70 normally restricts the movement of the inner needle 30 and the inner needle base 40 caused by the biasing force of the biasing member 60, and releases this restriction by moving them when the user presses them. Fig. 3 is an external perspective view of the switch member 70. As shown in the figure, the switch member 70 is composed of an exposed portion 71 having a substantially quadrangular pyramid shape, two substantially flat guide portions 72 extending downward from the exposed portion 71, and a substantially U-shaped restricting portion 73 provided to connect the two guide portions 72.

[0049] The exposed portion 71 is a portion that is exposed from the grip portion 51 of the housing 50 and is pressed by the user. The top surface 71a of the exposed portion 71 is an inclined surface 71b that is inclined so that the portion that becomes the tip side when placed in the grip portion 51 gradually becomes lower toward the tip side (i.e., gradually approaches the grip portion 51). In addition, engagement grooves 71c that engage with parts of the protector 80 are provided on the portions that become both side surfaces of the exposed portion 71 when placed in the grip portion 51.

[0050] The guide portion 72 is a portion that is accommodated in the recess 51e when placed in the grip portion 51, and is provided so as to slide along the inner surface of the recess 51e. The guide portion 72 also functions as a reinforcing member against the pressing force of the user. That is, the provision of the guide portion 72 increases the bending strength of the restricting portion 73, so that the switch member 70 is not easily damaged even when an excessive force is applied to the exposed portion 71.

[0051] The restricting portion 73 is a portion that is inserted into the slit 51h when placed in the gripping portion 51 and comes into contact with the base end face of the inner needle base 40. A first locking groove 73a and a second locking groove 73b having a substantially V-shaped cross section are provided on portions that become both side faces of the restricting portion 73 when placed in the gripping portion 51. Each corner of the restricting portion 73 is provided with a relatively large chamfer to prevent the restricting portion 73 from getting caught on the corners in the slit 51h during assembly or on the corners of the inner needle base 40 during operation.

[0052] The switch member 70 is disposed on the grip portion 51 so as to be movable between a restricting position where the movement of the inner needle 30 and the inner needle base 40 is restricted, and a releasing position where the restriction on the movement of the inner needle 30 and the inner needle base 40 is released. Fig. 1 and Figs. 2A and 2B show the switch member 70 in the restricting position. As shown in these figures, in the restricting position, substantially the entire exposed portion 71 is exposed from the grip portion 51, the inclined surface 71b is located on the tip side, and the engagement groove 71c is continuous in the axial direction. Also, the lower portion of the restricting portion 73 is in contact with the base end face of the inner needle base 40.

[0053] Figures 4A and 4B are cross-sectional views taken along line II-II in Figure 2A. Figure 4A shows the switch member 70 in the restricted position with the protector 80 attached. Figure 4B shows the switch member 70 in the released position with the protector 80 removed.

[0054] 4A, the protector 80 has a first engagement protrusion 82 on the inside, and when the protector 80 is attached to the housing 50, the first engagement protrusion 82 engages with the engagement groove 71c of the switch member 70. In other words, when the protector 80 is attached, the switch member 70 cannot move to the release position, and operation of the switch member 70 is reliably prevented.

[0055] In addition, a locking projection 51j having a substantially V-shaped cross section is provided on the inner surface of the slit 51h, and when the switch member 70 is in the restricted position, the locking projection 51j is accommodated in the first locking groove 73a and locked therein. Therefore, the switch member 70 is not easily moved even after the protector 80 is removed.

[0056] 4B, when the user presses the exposed portion 71, the switch member 70 moves downward toward the release position. At this time, the locking protrusion 51j escapes from the first locking groove 73a due to the elastic deformation of the restricting portion 73 or the gripping portion 51, and when the switch member 70 reaches the release position, the locking protrusion 51j is accommodated in the second locking groove 73b by the restoring force of the elastic deformation and is locked therein.

[0057] Thus, by providing the first locking groove 73a and the second locking groove 73b together with the locking protrusion 51j, not only is it possible to prevent the switch member 70 from being easily operated even after the protector 80 is removed, but it is also possible to make the user feel a clicking sensation when the switch member 70 is pressed. In other words, the user can know that the switch member 70 has moved to the release position by the feeling at his or her fingertip, and the operability of the indwelling needle assembly 1 is improved.

[0058] 4B, in the released position, the restricting portion 73 does not abut against the base end face of the inner needle base 40. Therefore, the inner needle base 40 passes through the inside of the restricting portion 73 together with the inner needle 30 and moves toward the base end side within the casing 50, and finally the inner needle 30 is accommodated in the casing 50.

[0059] FIG. 5 is a cross-sectional view showing a state in which the inner needle 30 is housed in the housing 50. As shown in the figure, the inner needle base 40 is pressed against the bottom 55 of the inner needle housing member 50b by the biasing member 60, and the entire inner needle 30 is housed in the housing 50. In addition, a part of the bottom 55 of the inner needle housing member 50b is housed in the housing section 44 of the inner needle base 40. By housing the bottom 55 in the housing section 44 in this way, the bottom 55, which is recessed to prevent the gate mark from protruding, can be utilized to stably hold the inner needle 30 in the housing 50, thereby improving safety. In addition, since the overall axial length of the housing 50 can be shortened, the indwelling needle assembly 1 can be made compact and operability can be improved.

[0060] The bottom 55 and the housing portion 44 may be fitted together to more reliably prevent the inner needle 30 from re-projecting. The filter 43 may be made of a material softer than the inner needle base 40, and the bottom 55 may be collided with the filter 43 to absorb the impact. The base member 50a and the switch member 70 may be configured so that the restricting portion 73 does not project from the base member 50a when the switch member 70 is in the release position. In this case, even when a finger is placed on the lower surface 51g of the grip portion 51, the operation of the switch member 70 can be prevented from being hindered by the finger.

[0061] 6A and 6B are diagrams showing a modified example of the switch member 70, and show the switch member 70 in the restricted position with the protector 80 removed.

[0062] 6A shows an example in which a leaf spring-like elastic member 74 is added to the switch member 70. In this example, the elastic member 74 is a flat plate-like member that is provided so as to protrude inward from the guide portion 72. The elastic member 74 comes into contact with a part of the grip portion 51 (in this example, an arc-shaped portion on the tip side of the bottom surface 51f of the recess 51e) and is deformed as the switch member 70 moves from the restricted position to the released position.

[0063] Providing the elastic member 74 in this manner provides appropriate resistance to the movement of the switch member 70, and makes it possible to push the switch member 70 back to the restricted position before the locking projection 51j locks with the second locking groove 73b. This makes it possible to prevent the switch member 70 from easily operating even after the protector 80 is removed, improving the operability of the indwelling needle assembly 1. It also makes it possible to provide the switch member 70 with a good operability.

[0064] 6B shows an example in which the anti-removal function of the switch member 70 is improved. In this example, the protrusion amount (height) of the locking projection 51j and the recess amount (depth) of the first locking groove 73a and the second locking groove 73b are increased, and the top of the protruding portion of the V-shaped cross section between the first locking groove 73a and the second locking groove 73b is cut out.

[0065] The locking projection 51j and the first locking groove 73a are configured to not only inhibit the switch member 70 from moving from the restricted position to the released position, but also inhibit the switch member 70 from moving from the restricted position to the opposite side of the released position (upward in the figure). That is, the locking projection 51j and the first locking groove 73a also function to prevent the switch member 70 from coming off from the grip portion 51. This function can be improved by increasing the protruding amount of the locking projection 51j and the recessed amount of the first locking groove 73a to increase the locking force, but simply increasing the locking force also increases the pressing force required to move the switch member 70 from the restricted position to the released position, resulting in a problem of deterioration in operability of the switch member 70.

[0066] Therefore, in this example, the top of the protruding portion between the first locking groove 73a and the second locking groove 73b is cut out, thereby reducing the height that the locking protrusion 51j must overcome when it moves from the restricted position of the switch member 70 toward the released position and escapes from the first locking groove 73a, thereby reducing the pressing force required to move the switch 70.

[0067] In this way, it is possible to prevent the pressing force required for operation from becoming excessively large while improving the anti-disengagement function of the switch member 70. In other words, according to the example shown in Fig. 6B, it is possible to achieve both good operability of the switch member 70 due to an appropriate click feeling and an appropriate pressing force, and reliable prevention of the switch member 70 from coming off.

[0068] 1 and 2A and B, the protector 80 is configured in a shape in which the opening side of a bottomed cylinder having a bottom 81 on the tip side is bulged to match the shapes of the grip part 51 of the housing 50 and the exposed part 71 of the switch member 70. The bottom 81 is configured in a shape that protrudes (is recessed) inwardly, similar to the bottom 55 of the inner needle housing member 50b, and an injection molding gate is disposed thereon. This improves the moldability of the protector 80 and allows for greater freedom in the shape of the protector 80. A flat surface 80a is provided on the lower side of the outer circumferential surface on the opening side of the protector 80 to prevent rolling.

[0069] Fig. 7A is an external perspective view of protector 80 as viewed from the opening side, Fig. 7B is a view of the inside of protector 80 as viewed from the opening side, and Fig. 7C is a cross-sectional view taken along line III-III in Fig. 7A. As described above, a first engagement protrusion 82 that engages with engagement groove 71c of switch member 70 is provided on the inner surface of protector 80. As described above, first engagement protrusion 82 not only prevents operation of switch member 70, but also prevents rattling of protector 80 in a direction perpendicular to the axial direction.

[0070] In addition, since the first engagement protrusion 82 is provided so as to be continuous in the axial direction, it also functions as a guide that restricts the movement direction of the protector 80 in the axial direction when the protector 80 is removed from the housing 50.

[0071] In this way, by engaging the protector 80 with the switch member 70, the degree of freedom of the shape of the housing 50 is increased, and each part such as the grip part 51 and the extension part 53 can be shaped to have excellent operability. Since the switch member 70 has an inclined surface 71b on the tip side, it has a shape that is not easily pressed by the edge of the protector 80 even after the first engagement protrusion 82 is released from the engagement groove 71c when the protector 80 is removed.

[0072] The inner surface of the protector 80 is further provided with two second engagement protrusions 83 that are continuous in a direction perpendicular to the axial direction. The second engagement protrusions 83 engage with the protruding portions at the tip ends of the left and right side surfaces 51a, 51b of the gripping portion 51 of the housing 50 (see FIG. 4A), thereby preventing the protector 80 from rattling and functioning as a retainer. Specifically, when the protector 80 is attached to the housing 50, the second engagement protrusions 83 overcome the protruding portions at the tip ends of the left and right side surfaces 51a, 51b of the gripping portion 51 due to elastic deformation of the protector 80 or the gripping portion 51, and then are pressed against the left and right side surfaces 51a, 51b.

[0073] The movement of the protector 80 toward the base end side is restricted by a vertical surface 85 provided on the rear side of the first engagement projection 82. That is, when the protector 80 is attached to the housing 50, the vertical surface 85 is brought into contact with the grip portion 51, so that the protector 80 can be positioned in the axial direction.

[0074] Also, on the inner surface of the protector 80, ribs 84 that come into contact with the outer needle base 20 at positions corresponding to the outer needle base 20 are provided at eight circumferential locations in order to prevent rattling on the tip side. In this way, by providing the ribs 84 that come into contact with the outer needle base 20 instead of the housing 50 to prevent rattling, the degree of freedom in the shape of the housing 50 can be increased.

[0075] Next, the extension portion 53 of the housing 50 will be described in detail.

[0076] 1 and 2A and B, the extension part 53 is composed of a substantially cylindrical first outer diameter part 53a connected to the grip part 51, a substantially hollow truncated cone-shaped reduced diameter part 53b that gradually reduces in diameter from the first outer diameter part 53a toward the tip side, and a substantially cylindrical second outer diameter part 53c that extends from the reduced diameter part 53b toward the tip side. In addition, a stopper 53d is provided on the lower side of the extension part 53 in the figure, i.e., on the outer circumferential surface that becomes the side to be punctured by the inner needle 30 and the outer needle 10 during use.

[0077] The first outer diameter portion 53a has a larger diameter than the second outer diameter portion 53c, and contains the large diameter portion 42 of the inner needle base 40 and a part of the urging member 60 therein. By providing such a first outer diameter portion 53a, the inner needle base 40 can be positioned closer to the tip side. This makes it possible to check for backflow blood inside the inner needle base 40 without being hindered by the hand or fingers gripping the grip portion 51.

[0078] The reduced diameter portion 53b is a portion that smoothly connects the outer peripheral surface of the first outer diameter portion 53a and the outer peripheral surface of the second outer diameter portion 53c. By providing such a reduced diameter portion 53b, it is possible to easily position the finger that presses the outer needle base 20 and to prevent the finger from getting caught when moving it.

[0079] The second outer diameter portion 53c is set to an outer diameter that allows it to be inserted into and fitted into the opening (e.g., luer taper) of the outer needle hub 20. In addition, by separately providing the stopper 53d, the second outer diameter portion 53c is configured to have approximately the same outer diameter even in the portion (non-inserted portion) that is not inserted into the opening of the outer needle hub 20. Therefore, the outer diameter difference D between the non-inserted portion of the second outer diameter portion 53c and the opening side end face 22 of the outer needle hub 20 is larger than when a conventional stepped cylinder is used. In other words, the opening side end face 22 of the outer needle hub 20 is in a state that is easy to press with a fingertip.

[0080] Furthermore, in this embodiment, by arranging the inner needle base 40 on the tip side of the restricting portion 73 of the switch member 70, the axial length of the second outer diameter portion 53c is set to a length appropriate for arranging the pad of a finger. This makes it possible to make the outer needle base 20 easier to press.

[0081] 8A is an external perspective view showing a part of the tip side of the base member 50a, as viewed from below. As shown in the figure, the stopper 53d is configured as a rib that partially protrudes in the centrifugal direction in the circumferential direction from the outer circumferential surfaces of the second outer diameter portion 53c and the reduced diameter portion 53b and is continuous in the axial direction. The stopper 53d is provided on the lower side of the second outer diameter portion 53c and the reduced diameter portion 53b, that is, in two places near the lowest part of the part that will be punctured by the inner needle 30 and the outer needle 10 when in use.

[0082] In this embodiment, the stopper 53d is configured such that the top surface is flush with and continuous with the outer circumferential surface of the first outer diameter portion 53a. In other words, it can be said that the reduced diameter portion 53b of the extension portion 53, the second outer diameter portion 53c, and the stopper 53d are configured by removing a part of a cylinder having the same outer diameter as the first outer diameter portion 53a.

[0083] 2B, the outer needle base 20 is arranged at a predetermined position in the axial direction by abutting the opening side end face 22 of the outer needle base 20 against the tip side end face 53e of the stopper 53d. At this time, the opening side end face 22 of the outer needle base 20 is mostly exposed, although a part of the lower side is hidden by the stopper 53d.

[0084] In this way, by making the stopper 53d partially protrude in the circumferential direction of the extension portion 53, the area that can be pressed on the opening side end surface 22 of the outer needle base 20 can be enlarged more than ever before. In particular, by forming the stopper 53d into a rib shape that is continuous in the axial direction, it is possible to utilize the stopper 53d as a reinforcing member, and it is therefore possible to ensure the strength and rigidity required for the extension portion 53 without enlarging the outer diameter of the non-inserted portion of the first outer diameter portion 53a. In addition, by making the stopper 53d protrude only in the lower portion where the fingertips are not placed in a normal use state, it is possible to ensure the strength and rigidity required for the extension portion 53 while preventing the stopper 53d from impeding the pressing operation by the fingertips.

[0085] Moreover, by providing the rib-shaped stoppers 53d at a plurality of locations (two locations in this embodiment) that are appropriately spaced apart in the circumferential direction of the extension portion 53, it is possible to achieve both the moldability of the base member 50a and stable positioning of the outer needle base 20. That is, while forming the stoppers 53d to be relatively narrow to prevent molding defects such as sink marks and voids, it is possible to abut against the outer needle base 20 at a plurality of locations in the circumferential direction to suppress tilting of the outer needle base 20 and stably hold the outer needle base 20.

[0086] 9 is a schematic diagram showing a state in which the indwelling needle assembly 1 is used. As shown in the figure, after removing the protector 80, the user holds the grip portion 51 of the housing 50 of the indwelling needle assembly 1 with, for example, the thumb and middle finger of the right hand wearing a glove, and punctures the inner needle 30 and the outer needle 10 into, for example, a blood vessel 110 of a living body 100. Then, after confirming backflow of blood between the outer needle 10 and the inner needle 30 and within the outer needle base 20 and the inner needle base 40, and judging that the tips of the inner needle 30 and the outer needle 10 are inserted into the blood vessel 110, the user presses the opening side end surface 22 of the outer needle base 20 with the tip of the index finger to insert only the outer needle 10 further deeper into the blood vessel 110.

[0087] The user can easily visually check the backflow of blood in the inner needle base 40 by simply moving the index finger slightly to the right (the back side of the figure) or the left (the front side of the figure). The user can also easily release the engagement between the outer needle base 20 and the second outer diameter portion 53c by placing the pad of the index finger on the non-inserted portion of the second outer diameter portion 53c and moving the fingertip along the second outer diameter portion 53c toward the tip side. At this time, the user may press a flange portion (a protrusion for a luer connector) provided on the outer needle base 20. The user can further push the outer needle base 20 further by moving the fingertip of the index finger toward the tip side, and can easily insert only the outer needle 10 deep into the blood vessel 110.

[0088] When the tip of the index finger is moved toward the tip, the index finger and palm as a whole move closer to the gripping portion 51. However, since the exposed portion 71 of the switch member 70 is provided with an inclined surface 71b, the user can push the outer needle base 20 forward with a natural motion without worrying about the index finger or palm touching the switch member 70.

[0089] In particular, in this embodiment, a rounded portion 51i is provided at the corner on the tip side of the grip portion 51, and a reduced diameter portion 53b is provided at the extension portion 53, so that the user can push forward the outer needle base 20 by only moving the third joint with the index finger extended substantially straight without being hindered by the grip portion 51 or the extension portion 53. That is, the rounded portion 51i and the reduced diameter portion 53b are inclined in the same direction as the inclined surface 71b on the upper side where the exposed portion 71 is arranged, and each constitutes an auxiliary inclined surface of the present invention.

[0090] In addition, since the stopper 53d is provided only near the bottom of the extension portion 53, the user can also move the index finger to the right or left to push the outer needle base 20 forward. In some cases, the user can also place the thumb of the left hand on the left side surface of the second outer diameter portion 53c to push the outer needle base 20 forward. In other words, the indwelling needle assembly 1 is not only excellent in operability, but also has a high degree of freedom in operation.

[0091] 8B to 8D are external perspective views showing a modified example of stopper 53d, with FIGS. 8B and 8C showing the stopper 53d as viewed from below, and FIG. 8D showing the stopper 53d as viewed from above.

[0092] The stopper 53d is not limited to being provided at two locations near the bottom of the lower side, which is the puncture target side of the inner needle 30 and the outer needle 10 during use, but may be provided at other locations, or may be provided at only one location, or may be provided at three or more locations. For example, as shown in Fig. 8B, in addition to being provided near the bottom of the lower side of the extension part 53, the stopper 53d may also be provided on the upper side. That is, the stopper 53d may be provided at a position that does not interfere with the pressing operation of the user, and by providing the stopper 53d on the upper side as well as the lower side of the extension part 53 in this way, it is possible to prevent the outer needle base 20 from rattling and to hold it more stably.

[0093] Furthermore, in this case, the protruding amount of the upper stopper 53d may be made smaller than the protruding amount of the lower stopper 53d. That is, the protruding amount of the stopper 53d may differ depending on the circumferential position of the extension portion 53. For example, by reducing the protruding amount of the stopper 53d close to the position where the user's fingertip is placed, it is possible to improve operability and freedom of operation.

[0094] Also, the stopper 53d may be configured so that the amount of protrusion varies in the circumferential direction, rather than protruding partially in the circumferential direction of the extension portion 53. For example, as shown in Fig. 8C, a rib-shaped stopper 53d with a large amount of protrusion and a ring-shaped stopper 53d with a small amount of protrusion may be combined, so that the amount of protrusion of the portion other than the vicinity of the lowest part on the lower side is set to the amount of protrusion where the opening side end face 22 of the outer needle base 20 is exposed, and the amount of protrusion of the portion near the lowest part on the lower side is larger than the amount of protrusion of the other portions. That is, the amount of protrusion of the stopper 53d may be partially reduced in the circumferential direction, thereby increasing the area where the opening side end face 22 of the outer needle base 20 can be pressed.

[0095] Also, the stopper 53d may be formed by cutting out a part of the step of a stepped cylinder, as shown in Fig. 8D. In the example shown in the figure, the extension 53 is formed in a stepped cylinder shape consisting of a first outer diameter portion 53a and a second outer diameter portion 53c, and the first outer diameter portion 53a functions as a stopper, and the upper side of the first outer diameter portion 53a is cut out to provide a recess 53f. In this case, too, by placing a fingertip in this recess 53f, the opening side end surface 22 of the outer needle base 20 can be easily pressed. Also, it is possible to make the inclined portion of the recess 53f form an auxiliary inclined surface.

[0096] Although not shown in the drawings, the shape of the stopper 53d is not particularly limited, and may be, for example, a projection such as a prism or cylinder. The stopper 53d may be configured by eccentrically distributing the small diameter portion and the large diameter portion of a stepped cylinder. The stopper 53d is not limited to a surface that is substantially parallel to the opening end face 22 of the outer needle base 20, and may be a surface that is angled with respect to the opening end face 22 and abuts against the outer needle base 20. Specifically, the stopper 53d may be, for example, a pyramidal or hemispherical projection, or the second outer diameter portion 53c may be partially tapered in the circumferential direction to expand in a tapered manner, or the inclination angle may be changed in the circumferential direction to expand in a tapered manner to configure the stopper 53d.

[0097] Next, a description will be given of modified examples of the inner needle base 40 and the housing 50. In the following modified examples, the same parts as those in the above-mentioned example are given the same reference numerals, and the description thereof will be omitted.

[0098] FIG. 10A is a plan view (top view) of a modified example of the inner needle hub 40, FIG. 10B is a side view of a modified example of the inner needle hub 40, and FIG. 10C is a cross-sectional view taken along line IV-IV in FIG. 10A. In this example, first, recesses 41c are provided at four locations on the outer circumferential surface of the inner needle fixing portion 41b of the small diameter portion 41. The inner needle fixing portion 41b is thicker than other portions, but by providing appropriate recesses 41c at multiple locations in this manner, it is possible to prevent the occurrence of sink marks, voids, and the like during injection molding while maintaining the strength of the inner needle fixing portion 41b, and improve moldability. In this example, a case where recesses 41c having a flat rectangular bottom surface are provided is shown, but the shape of the recesses 41c may be other shapes. In addition, the number of recesses 41c is not limited.

[0099] In this example, a tapered portion 46 is provided between the small diameter portion 41 and the large diameter portion 42. Planar portions 42b are provided at two locations on the large diameter portion 42 that are opposite to each other. The planar portions 42b are Large diameter section 42 The distance between the two flat portions 42b is approximately equal to the outer diameter of the small diameter portion 41.

[0100] In this way, by providing the flat surface portion 42b on the substantially stepped cylindrical inner needle base 40, it is possible to provide directionality in the circumferential direction, which facilitates the assembly of the indwelling needle assembly 1 by an automated machine and improves productivity. Specifically, for example, the circumferential direction of the inner needle base 40 can be determined by gripping the flat surface portion 42b, which makes it possible to easily position the anti-rotation protrusion 41a when inserting the inner needle base 40 into the base member 50a.

[0101] In this example, a rounded portion 45a is provided at the corner portion on the base end side of the force receiving portion 45. By providing the rounded portion 45a in this manner, it is possible to prevent the switch member 70 from getting caught, and to improve the ease of assembly and operability.

[0102] In this example, a generally funnel-shaped adhesive accommodating portion 41d is provided on the inside of the inner needle fixing portion 41b on the tip side, and an outflow prevention portion 41e with an inner diameter slightly larger than the outer diameter of the inner needle 30 is provided on the base side. By configuring the inside of the inner needle fixing portion 41b in this manner, outflow of the adhesive to the base end side (outflow to the flash chamber portion 47 described below) is prevented, enabling reliable fixation of the inner needle 30. The outflow prevention portion 41e is configured in a tapered shape that expands slightly in diameter toward the tip side except for a part on the base end side, so that a small amount of adhesive also flows into the outflow prevention portion 41e.

[0103] Furthermore, between the inner needle fixing part 41b and the housing part 44 inside the inner needle base 40 in this example, a flash chamber part 47 that stores blood that has passed through the inner needle 30 is provided on the tip side, and a filter mounting part 48 in which the filter 43 is disposed is provided on the base end side. The inner diameter of the filter mounting part 48 is larger than the inner diameter of the flash chamber part 47, and the filter 43 is positioned in the axial direction by abutting against a step part 49 between the two. Furthermore, the inner circumferential surface of the housing part 44 is smoothly continuous with the inner circumferential surface of the filter mounting part 48, making it possible to smoothly insert the filter 43 from the base end side and place it in the filter mounting part 48.

[0104] Fig. 11A is a cross-sectional view taken along line IV-IV in Fig. 10A, and illustrates a case in which a flow passage 41f having a smaller diameter than the outflow prevention portion 41e is provided between the outflow prevention portion 41e and the flash chamber portion 47 in the inner needle base 40 shown in Figs. 10A to 10C. This flow passage 41f has approximately the same inner diameter as the inner needle 30, and is provided so as to communicate with the inside of the inner needle 30 fixed to the inner needle fixing portion 41b. Therefore, blood that has passed through the inner needle 30 flows into the flash chamber portion 47 via the flow passage 41f.

[0105] In this manner, by providing the flow passage 41f having a smaller diameter than the outflow prevention portion 41e, it is possible to more reliably prevent the adhesive from outflowing to the flash chamber portion 47. Furthermore, by abutting the base end face of the inner needle 30 against the step portion 41g between the outflow prevention portion 41e and the flow passage 41f, it is possible to facilitate positioning of the inner needle 30 in the axial direction.

[0106] 11B is a side view showing a case where a friction part 90 is provided on the inner needle hub 40 shown in FIGS. 10A to 10C. The friction part 90 is made of a ring-shaped (annular) member fitted to the outer circumferential surface of the large diameter part 42 at a position adjacent to the force receiving part 45 in the axial direction. The ring-shaped member is made of an elastomer (elastic material) such as synthetic rubber that is softer than the resin constituting the inner needle hub 40. The outer diameter of the friction part 90 is set to be approximately the same as the outer diameter of the force receiving part 45 (i.e., the maximum outer diameter of the inner needle hub) or slightly larger than the outer diameter of the force receiving part 45. That is, the friction part 90 functions as a brake that reduces the moving speed of the inner needle hub 40 by contacting the inner circumferential surface of the housing 50 (the base member 50a or the inner needle housing member 50b) when the inner needle hub 40 moves due to the biasing force of the biasing member 60.

[0107] Conventional indwelling needle assemblies have had the problem that when the inner needle is housed in the housing by the biasing force of a coil spring or the like, blood adhering to or remaining on the inner needle may splash around depending on the movement speed of the inner needle and the inner needle base. Therefore, even though a mechanism for housing the inner needle in the housing is provided, there is a risk of viral infection, etc., if the splashed blood adheres to the user, etc.

[0108] 11B is an attempt to provide a safer indwelling needle assembly 1 in view of the above circumstances. That is, by providing a friction portion 90, which is configured to generate a greater frictional force between the inner needle base 40 and the casing 50 than other portions of the inner needle base 40, at a position on the inner needle base 40 where it can come into contact with the casing 50, it is possible to reduce the moving speed of the inner needle base 40 and prevent blood from splashing from the inner needle 30.

[0109] The material of the friction portion 90 is not particularly limited, and various known materials can be used. The shape of the friction portion 90 is not particularly limited, and the friction portion 90 may be configured so that the outer peripheral surface has an elliptical shape, a polygonal shape, or the like when viewed from the axial direction. The surface (outer peripheral surface) of the friction portion 90 that comes into contact with the housing 50 may be a flat surface or a curved surface. The surface of the friction portion 90 that comes into contact with the housing 50 may be provided with a protrusion or an uneven shape, and the friction portion 90 may bite into the inner peripheral surface of the housing 50, thereby increasing the frictional force.

[0110] The friction portion 90 may be configured by fixing a member separate from the inner needle base 40 to the inner needle base 40 by fitting, engaging, bonding, or the like, or may be configured by integrally forming a separate member with the inner needle base 40 by insert molding. Also, the friction portion 90 may be configured by partially changing the shape of the inner needle base 40, rather than by using a different material.

[0111] 11B, as described above, a ring-shaped member made of a flexible elastomer is fitted onto the outer peripheral surface of the inner needle base 40, thereby making it possible to provide the friction portion 90 without incurring a significant increase in cost or deterioration in productivity. In addition, by disposing the ring-shaped member constituting the friction portion 90 between the biasing member 60 and the force receiving portion 45, it is possible to prevent the friction portion 90 from shifting in position while maintaining a simple and inexpensive configuration, and to ensure the deceleration function.

[0112] 12A is a plan view (top view) of a modified example of the housing 50, and FIG. 12B is a side view of the modified example of the housing 50. FIG. 13A is a bottom view (underside view) of the modified example of the housing 50, and FIG. 13B is a cross-sectional view taken along line VV in FIG. 12A. In FIG. 13B, the base member 50 a 4 shows the inner needle housing member 50b in exploded view.

[0113] In this example, first, the portion of the second outer diameter portion 53c of the extension portion 53 that is further distal than the stopper 53d is tapered to correspond to the luer taper of the outer needle base 20. This makes it possible to hold the outer needle base 20 more stably. In addition, rounded corners 51k and 51l are provided at the upper edge of the slit 51h. This prevents the switch member 70 from getting caught when it is inserted into the slit 51h during assembly, improving ease of assembly.

[0114] In this example, a lower recess 51m similar to the recess 51e on the upper surface 51d side is provided on the lower surface 51g side of the base member 50a, and the thickness of the lower portion of the base member 50a on the tip side of the slit 51h is reduced. In this way, it is possible to prevent the occurrence of sink marks and voids during injection molding of the base member 50a and improve moldability.

[0115] In this example, anti-rotation grooves 54c are provided in two places, on the left and right sides, in the first inner diameter portion 54a of the through hole 54 of the base member 50a. Normally, a user checks for backflow of blood into the inner needle base 40 by visually checking from above, so by arranging the anti-rotation grooves 54c on the sides in this manner, it is possible to improve the visibility of backflow of blood.

[0116] In addition, chamfers 54d, 54e are provided on the corners on the base end side of the first inner diameter portion 54a and the anti-rotation groove 54c, respectively. By providing such chamfers 54d, 54e, it becomes possible to prevent the small diameter portion 41 of the inner needle base 40 from getting caught when being inserted into the first inner diameter portion 54a, and to improve the ease of assembly.

[0117] Furthermore, in this example, by eliminating the reduced diameter portion on the tip side of the second inner diameter portion 54b of the through hole 54, the tip side end of the urging member 60 is reliably abutted against the step portion 54f between the first inner diameter portion 54a and the second inner diameter portion 54b, thereby prioritizing the stability of the operation of the urging member 60.

[0118] Moreover, the inner needle accommodating member 50b in this example is composed of a connected portion 57 on the tip side to which the connecting portion 52 of the base member 50a is connected, and a main body portion 58 on the base side, and both the outer diameter and the inner diameter of the main body portion 58 are smaller than those of the connected portion 57. By configuring the inner needle accommodating member 50b in such a stepped bottomed cylindrical shape, it is possible to press the step portion 59 between the connected portion 57 and the main body portion 58 to move the inner needle accommodating member 50b toward the base member 50a and fit it into the base member 50a, thereby improving the ease of assembly. Furthermore, it is possible to configure the inner circumferential surface 58a of the main body portion 58b to have approximately the same inner diameter as the second inner diameter portion 54b of the through hole 54 of the base member 50a without increasing the wall thickness, so that the inner needle base 40 and the biasing member 60 can be appropriately restrained and stably moved even within the inner needle accommodating member 50b.

[0119] In addition, the outer peripheral surface of the connection portion 52 of the base member 50a in this example is provided with a first Support outer diameter portion 52b The first support outer diameter portion 52b has a second support outer diameter portion 52c on the base end side, and a fitting outer diameter portion 52d between the first support outer diameter portion 52b and the second support outer diameter portion 52c. The outer diameter of the first support large outer diameter portion 52b is larger than that of the second support outer diameter portion 52c, and the outer diameter of the fitting outer diameter portion 52d is larger than that of the first support outer diameter portion 52b. In addition, intermediate tapered outer diameter portions 52e and 52f are provided between the first support outer diameter portion 52b and the fitting outer diameter portion 52d, and between the second support outer diameter portion 52c and the fitting large diameter portion 52d, respectively.

[0120] The inner peripheral surface of the connected portion 57 of the inner needle housing member 50b is provided with a first support inner diameter portion 57b on the tip side, a second support inner diameter portion 57c on the base end side, and a fitting inner diameter portion 57d between the first support inner diameter portion 57b and the second support inner diameter portion 57c. The inner diameter of the first support inner diameter portion 57b is set to be substantially the same as that of the first support outer diameter portion 52b, and the inner diameter of the second support inner diameter portion 57c is set to be substantially the same as that of the second support outer diameter portion 52c. The inner diameter of the fitting inner diameter portion 57d is set to be smaller than the outer diameter of the fitting outer diameter portion 52c and larger than the first support inner diameter portion 57b. Further, intermediate tapered inner diameter portions 57e, 57f are provided between the first support inner diameter portion 57b and the fitting inner diameter portion 57d, and between the second support inner diameter portion 57c and the fitting inner diameter portion 57d, respectively.

[0121] By configuring the connecting portion 52 and the connected portion 57 in this manner, it is possible to achieve both a reliable connection between the base member 50a and the inner needle housing member 50b and ease of assembly. c The outer diameter of the second support inner diameter portion 57c is smaller than that of the first support inner diameter portion 57b, which facilitates insertion of the connecting portion 52 into the connected portion 57 and facilitates elastic deformation when the first support inner diameter portion 57b overcomes the fitting outer diameter portion 52b. When the fitting outer diameter portion 52d and the intermediate tapered outer diameter portions 52e, 52f are fitted to the fitting inner diameter portion 57d and the intermediate tapered inner diameter portions 57e, 57f, the first support outer diameter portion 52b and the first support inner diameter portion 57b are disposed in corresponding positions, and the second support outer diameter portion 52c and the second support inner diameter portion 57c are disposed in corresponding positions, so that a reliable connection with little rattling can be obtained.

[0122] In this example, a base end tapered outer diameter portion 52g whose outer diameter gradually decreases toward the base end is provided on the base end side of the second support outer diameter portion 52c, and a tip end tapered inner diameter portion 57a ​​whose inner diameter gradually increases toward the tip end is provided on the tip end side of the first support inner diameter portion 57b, making it easier to insert the connecting portion 52 into the connected portion 57.

[0123] Although an embodiment of the present invention has been described above, the indwelling needle assembly of the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0124] For example, the shape and arrangement of each part of the indwelling needle assembly 1 are not limited to those shown in the above embodiment, and various known shapes and arrangements can be adopted. Furthermore, the indwelling needle assembly 1 may have the inner needle 30 fixed to the housing 50, and may not have the inner needle base 40, the biasing member 60, and the switch member 70. Furthermore, the indwelling needle assembly 1 is not limited to being used on living organisms such as humans and animals, and may be used on organisms other than living organisms.

[0125] Furthermore, the actions and effects shown in the above embodiments are merely a list of the most preferable actions and effects resulting from the present invention, and the actions and effects of the present invention are not limited to these. [Explanation of symbols]

[0126] 1. Indwelling needle assembly 10 Outer needle 20 Outer needle base 30 Inner Needle 40 Inner needle base 50 Case 51 Gripping part 51i Roundness 53 Extension 53b Reduced diameter part 53d Stopper 60 biasing member 70 Switch parts 71 Exposed part 71a Top surface 71b Slope

Claims

1. A tubular outer needle; an outer needle base to which a base end portion of the outer needle is fixed; an inner needle inserted into the outer needle and the outer needle base; a housing that holds the inner needle and detachably holds the outer needle base at one end thereof, the housing has a grip portion to be gripped by a user, and an extension portion provided to extend from the grip portion in an axial direction of the inner needle and to hold an outer needle base at a tip portion, the extension portion has a stopper on an outer circumferential surface thereof for positioning the outer needle base in the axial direction of the inner needle, the stopper is configured to partially protrude in a circumferential direction of the inner needle, or is configured so that an amount of protrusion thereof varies in the circumferential direction of the inner needle, an inner needle base having a base end portion of the inner needle fixed thereto and disposed in the housing so as to be movable in an axial direction of the inner needle; a biasing member that biases the inner needle base toward the other end of the housing; a switch member that is arranged in the housing so as to be movable between a restricting position that restricts movement of the inner hub and a releasing position that releases the restriction on the movement of the inner hub, the switch member is disposed on the extension side of the grip portion and has an exposed portion exposed from the grip portion, The exposed portion is configured to have a shape having an inclined surface whose top surface on the extension portion side gradually approaches the grip portion toward the extension portion side, The indwelling needle assembly, wherein the gripping portion or the extending portion has an auxiliary inclined surface between the exposed portion and the outer needle base, the auxiliary inclined surface being inclined in the same direction as the inclined surface.

2. The indwelling needle assembly according to claim 1, The indwelling needle assembly, wherein the stopper is configured as a rib that is continuous in the axial direction of the inner needle.

3. The indwelling needle assembly according to claim 1 or 2, an indwelling needle assembly characterized in that the stopper is configured to protrude only at the portions of the inner needle and the outer needle that are to be punctured, or is configured so that the amount of protrusion of the portions that are to be punctured is greater than that of other portions.

Images