JP7634150B2 - Indwelling needle assembly - Google Patents

Description

The present invention relates to an indwelling needle assembly that includes an indwelling needle that is inserted into a blood vessel or the like and used to connect to an infusion line or the like.

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 retained outer needle. In recent years, in order to prevent virus infections or the like caused by touching the inner needle after removal, indwelling needle assemblies that make it possible to store the inner needle in a housing by a coil spring or the like after removal have become widespread (see, for example, Patent Document 1).

In this type of 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 the outer needle alone is pushed further along the inner needle, thereby inserting 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 the fingers.

More specifically, the outer needle base is usually held in engagement with one end of the casing that contains the inner needle after removal, so the user can, for example, hold the casing with their thumb and middle finger and press the outer needle base with their index finger to release the engagement with the casing and push only the outer needle into the inside of a blood vessel, etc.

JP 2007-296022 A

However, the indwelling needle assembly described in Patent Document 1 had a problem that it was 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 or the like. 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.

For this reason, depending on the level of proficiency of the user (such as a doctor or nurse), it may be difficult to operate with one hand, and it may be necessary, for example, to 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.

In view of the above circumstances, the present invention aims to provide an indwelling needle assembly that is easy to operate.

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 that is 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 of itself, the casing having a grip portion to be 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 configured so that the amount of protrusion varies in the circumferential direction of the inner needle , the base end of the inner needle is fixed the switch member is arranged on the extension side of the gripping portion and has an exposed portion exposed from the gripping portion, the top surface of the exposed portion side being configured to have 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, the auxiliary inclined surface being inclined in the same inclination direction as the inclined surface, the switch member being arranged on the extension side of the gripping portion and having an exposed portion exposed from the gripping portion, the top surface of the exposed portion side being configured to have 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, the auxiliary inclined surface being inclined in the same inclination direction as the inclined surface .

According to the present invention, the difference in outer diameter between the outer needle base and the extending portion can be increased in a portion other than the stopper, so that the outer needle base can be easily pressed. 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, and the operability of the indwelling needle assembly can be improved. In addition, when trying to push 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 completed. However, by configuring the exposed portion to have a shape in which the top surface on the extending portion side has an inclined surface that gradually approaches the gripping portion toward the extending portion 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, and thus the operability can be improved. Furthermore, by configuring the outer needle base to have an auxiliary inclined surface between the exposed portion and the outer needle base that is inclined in the same direction as the inclined surface, it is possible to push the outer needle base with fingers extended approximately straight without being hindered by the gripping portion or extension portion, making it easier to press the outer needle base and ensuring the effect of the inclined surface regardless of the shape of the gripping portion or extension portion.

In addition, in the present invention, it is preferable that the stopper is configured in the form of a rib that is continuous in the axial direction of the inner needle.

This allows the strength and rigidity of the extension to be secured by using the stopper as a reinforcing member, so the extension can be made smaller in diameter. This allows the difference in outer diameter between the outer needle base and the extension to be larger in areas other than the stopper, making it easier to press the outer needle base.

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.

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

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 pressing of the outer needle base is finished.

The indwelling needle assembly of the present invention can provide the excellent effect of improving operability.

FIG. 1 is a partially exploded external perspective view of an indwelling needle assembly according to an embodiment of the present invention. 2 is a cross-sectional view taken along line II in FIG. 1. FIG. 2. This is a cross-sectional view taken along line II-II in FIG. FIG. 11 is a cross-sectional view showing a state in which the inner needle is housed in the housing. FIG. 11 is a cross-sectional view showing a modified example of the switch member. FIG. FIG. 4 is an external perspective view showing a part of the tip side of the base member. FIG. 2 is a schematic diagram showing a state in which the indwelling needle assembly is used. FIG. 13 is a diagram showing a modified example of the inner needle base. FIG. 13 is a diagram showing a modified example of the inner needle base. FIG. 13 is a diagram showing a modified example of the housing. FIG. 13 is a diagram showing a modified example of the housing.

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 I-I in Fig. 1, and Fig. 2B is a cross-sectional view showing an enlarged portion of Fig. 2A.

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 retained therein, 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 accommodates the inner needle base 40 so as to be movable in the axial direction of the inner needle 30, a biasing member 60 arranged within 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.

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 portion of the housing 50, and the switch member 70, and is removed when in use. Note that Figures 1 and 2B show the state in which the protector 80 has been removed, and Figure 2A shows the state in which the protector 80 has been attached to the housing 50.

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. In addition, the indwelling needle assembly 1 is usually used in a position in which 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.

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 approximately stepped truncated cone shape for connecting an infusion line, a syringe, etc. to the outer needle 10, and is equipped with a luer connector of a specified 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.

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

The inner needle 30 is a tubular member with a blade surface formed at the tip, and is made of a suitable metal or resin that is more rigid than the outer needle 10. The tip shape of the inner needle 30 is not particularly limited, and may be back-cut or lancet-processed to reduce puncture resistance. 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.

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.

The inner needle base 40 is a roughly stepped cylindrical member for supporting the inner needle 30, and is composed of a small diameter section 41 on the tip side and a large diameter section 42 on the base side. Anti-rotation protrusions 41a are provided in two places on the outer peripheral surface on the base side of the small diameter section 41 to prevent relative rotation between the inner needle base 40 and the housing 50. In addition, an inner needle fixing section 41b with a reduced inner diameter is provided on the tip side of the small diameter section 41.

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 is connected to 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 translucent resin, so that the user can check for backflow of blood at the inner needle base 40 as well.

The opening on the base end side of the large diameter portion 42 of the inner needle base 40 is blocked 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 material, 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 out to the outside. The filter 43 is inserted into the large diameter portion 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 portion 42.

The inner circumferential surface of the large diameter section 42 on the base end side of 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 of the filter 43 constitutes a housing section 44 that houses a part of the housing 50. Details of the housing section 44 will be described later. A brim-shaped force receiving section 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 section 42.

The housing 50 holds each part of the indwelling needle assembly 1 and is held by the user. The housing 50 is configured as a bottomed tube 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 long enough to accommodate the entire inner needle 30 removed from the outer needle 10 together with the inner needle base 40.

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 that extends from the base end side of the gripping portion 51, and an approximately funnel-shaped extending portion 53 that extends 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 translucent resin, and as described above, backflow blood in the inner needle base 40 can be visually observed from the outside.

The gripping portion 51 is a portion for the user to grip. The gripping portion 51 is configured with an external 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 gradually separates 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.

The tip side of the upper surface 51d of the gripping portion 51 is provided with a generally rectangular prism-shaped recess 51e and a slit 51h that penetrates between the bottom surface 51f of the recess 51e and the lower surface 51g of the gripping portion 51. The switch member 70, which will be described later, is inserted into the recess 51e and the slit 51h. The region of the upper surface 51d that is closer to the base end than the recess 51e is configured to have 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 in such a way that the thumb is placed on the upper surface 51d and the index finger is placed on the lower surface 51g (so-called vertical holding).

In addition, by configuring the gripping portion 51 in a generally rectangular 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 on the housing 50 to prevent rolling, 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 gripping portion 51 to protrude outward, not only is the operability during puncturing improved as described above, but the anti-rolling function is also improved.

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

The connecting portion 52 is inserted into the inner needle housing member 50b and fitted into it. The outer diameter of the connecting portion 52 is set to be 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 in the middle of the connecting portion 52 slightly toward the tip.

The extension 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 details of the extension portion 53 will be described later.

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 of the extension portion 53, and the other portion of the through hole 54 is the second inner diameter portion 54b. In addition, anti-rotation grooves 54c in which anti-rotation protrusions 41a of the inner needle base 40 are accommodated are provided at two locations on the base end side of the first inner diameter portion 54a.

The inner needle base 40 is arranged with the tip of the small diameter portion 41 protruding from the extension portion 53 at 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 with little rattle. In this state, the anti-rotation protrusion 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.

The inner needle housing member 50b is a cylindrical member with a bottom that has a slightly reduced outer diameter toward the base end and a bottom 55 on the base end side. The inner peripheral surface of the inner needle housing member 50b is provided with a circumferentially continuous retaining groove 56 at a position corresponding to the retaining protrusion 52a of the connection portion 52 of the base member 50a. The retaining groove 56 and the retaining protrusion 52a engage with each other to prevent the base member 50a and the inner needle housing member 50b from being easily separated.

In addition, the inner needle housing member 50b is made of an appropriate resin, and the bottom 55 has a shape that protrudes inward (is recessed) due to the mold structure during resin molding. That is, the bottom 55 is the portion where the gate (the inlet of the resin flowing into the mold cavity) of the injection molding is placed, and by recessing it so that the thickness is approximately constant, the occurrence of sink marks and voids is prevented, while the gate mark, which may become a sharp cut mark, does not protrude outward. By placing 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 protrusion of the gate mark 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.

The biasing member 60 is a coil spring that biases the inner needle 30 toward the base end after removal and retracts it into the housing. The biasing member 60 is arranged 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.

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

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. Figure 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.

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, the portions that become both side surfaces of the exposed portion 71 when placed in the grip portion 51 are each provided with an engagement groove 71c that engages with a part of the protector 80.

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 against the inner surface of the recess 51e. The guide portion 72 also functions as a reinforcing member against the pressing force of the user. In other words, 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.

The restricting portion 73 is inserted into the slit 51h when placed in the gripping portion 51 and abuts against the base end face of the inner needle base 40. A first locking groove 73a and a second locking groove 73b with a substantially V-shaped cross section are provided on the 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 it from getting caught on the corners in the slit 51h during assembly or on the corners of the inner needle base 40 during operation.

The switch member 70 is arranged 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. Figure 1 and Figures 2A and B show the switch member 70 in the restricting position. As shown in these figures, in the restricting position, almost 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. In addition, the lower portion of the restricting portion 73 is in contact with the base end surface of the inner needle base 40.

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 moved to the released position with the protector 80 removed.

4A, the protector 80 has a first engagement protrusion 82 on the inside, and when the protector 80 is attached to the housing 50, this 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.

In addition, a locking projection 51j with 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, this locking projection 51j is accommodated in the first locking groove 73a and is locked in place. Therefore, the switch member 70 is not easily moved even after the protector 80 is removed.

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 restoring force of the elastic deformation causes the locking protrusion 51j to be accommodated in the second locking groove 73b and lock therein.

In this way, by providing the first and second locking grooves 73a and 73b together with the locking projection 51j, not only is it possible to prevent the switch member 70 from easily operating even after the protector 80 is removed, but it is also possible to provide the user with 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 feel of his or her fingertip, improving the operability of the indwelling needle assembly 1.

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 housing 50, and finally the inner needle 30 is accommodated within the housing 50.

5 is a cross-sectional view showing the 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.

The bottom 55 and the storage 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.

Figures 6A and B show a modified example of the switch member 70, showing the switch member 70 in the restricted position with the protector 80 removed.

Figure 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 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, the arc-shaped portion at the tip side of the bottom surface 51f of the recess 51e) and deforms as the switch member 70 moves from the restricted position to the released position.

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 protrusion 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.

Figure 6B shows an example in which the anti-removal function of the switch member 70 has been 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.

The locking protrusion 51j and the first locking groove 73a not only prevent the switch member 70 from moving from the restricted position to the released position, but also prevent 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 protrusion 51j and the first locking groove 73a also function to prevent the switch member 70 from coming off the grip portion 51. This function can be improved by increasing the protrusion amount of the locking protrusion 51j and the recess amount of the first locking groove 73a to increase the locking force, but simply increasing the locking force will increase the pressing force required to move the switch member 70 from the restricted position to the released position, which will cause a problem of deterioration in the operability of the switch member 70.

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 to reduce the height that the locking protrusion 51j must overcome when it moves from the restricted position to the released position and escapes from the first locking groove 73a, thereby reducing the pressing force required to move the switch 70.

In this way, it is possible to improve the anti-removal function of the switch member 70 while preventing the pressing force required for operation from becoming excessively large. In other words, according to the example shown in Fig. 6B, it is possible to achieve both good operability of the switch member 70 through an appropriate clicking sensation and an appropriate pressing force, and reliable prevention of the switch member 70 from coming off.

1 and 2A and B, the protector 80 is configured as a bottomed cylinder having a bottom 81 at the tip side, with the opening side bulging out to match the shapes of the gripping portion 51 of the housing 50 and the exposed portion 71 of the switch member 70. The bottom 81 is configured as a shape that protrudes inward (recessed) like 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 portion 80a is provided on the underside of the outer circumferential surface at the opening side of the protector 80 to prevent rolling.

Figure 7A is an external perspective view of protector 80 as viewed from the opening side, Figure 7B is a view of the inside of protector 80 as viewed from the opening side, and Figure 7C is a cross-sectional view taken along line III-III in Figure 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 functions to prevent rattling of protector 80 in a direction perpendicular to the axial direction.

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

In this way, by engaging the protector 80 and the switch member 70, the 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. In addition, since the switch member 70 has an inclined surface 71b on the tip side, it is shaped so that it 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.

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 side 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 side of the left and right side surfaces 51a, 51b of the gripping portion 51 due to the elastic deformation of the protector 80 or the gripping portion 51, and then press against the left and right side surfaces 51a, 51b.

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

The inner surface of the protector 80 is also provided with eight circumferential ribs 84 that abut against the outer needle base 20 at positions corresponding to the outer needle base 20 to prevent rattling at the tip side. In this way, by providing the ribs 84 that abut against the outer needle base 20 instead of the housing 50 to prevent rattling, the freedom of the shape of the housing 50 can be increased.

Next, details of the extension portion 53 of the housing 50 will be described.

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

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 biasing member 60 inside. By providing such a first outer diameter portion 53a, the inner needle base 40 can be positioned closer to the tip. This makes it possible to check for backflow of blood inside the inner needle base 40 without being obstructed by the hand or fingers gripping the grip portion 51.

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 eliminate the possibility of the finger getting caught when moving.

The second outer diameter portion 53c is set to an outer diameter that can be inserted and fitted into the opening (e.g., luer taper) of the outer needle base 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 base 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 base 20 is larger than when a conventional stepped cylinder is used. In other words, the opening side end face 22 of the outer needle base 20 is in a state that is easy to press with a fingertip.

In this embodiment, the inner needle base 40 is disposed on the tip side of the restricting portion 73 of the switch member 70, so that the axial length of the second outer diameter portion 53c is set to a length appropriate for placing the pad of a finger. This makes it easier to press the outer needle base 20.

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 also provided at two locations below the second outer diameter portion 53c and the reduced diameter portion 53b, that is, near the lowest part of the part that will be punctured by the inner needle 30 and the outer needle 10 when in use.

In this embodiment, the stopper 53d is configured so 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.

As shown in Fig. 2B, the outer needle base 20 is positioned at a predetermined position in the axial direction by abutting the opening end face 22 of the outer needle base 20 against the tip end face 53e of the stopper 53d. At this time, the opening end face 22 of the outer needle base 20 is mostly exposed, although a portion of the lower side is hidden by the stopper 53d.

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 expanded more than ever before. In particular, by making the stopper 53d into a rib shape that continues in the axial direction, it is possible to utilize the stopper 53d as a reinforcing member, so that it is possible to ensure the strength and rigidity required for the extension portion 53 without expanding 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 normal use, 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 with the fingertips.

In addition, by providing the rib-shaped stopper 53d at multiple 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 the stopper 53d is configured 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 multiple locations in the circumferential direction to suppress tilting of the outer needle base 20 and stably hold the outer needle base 20.

9 is a schematic diagram showing the in-use state of the indwelling needle assembly 1. As shown in the figure, after removing the protector 80, the user grasps the gripping 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, for example, the blood vessel 110 of the living body 100 with the inner needle 30 and the outer needle 10. 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 open 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.

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 (back side of the figure) or left (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 the flange portion (protrusion for lure 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 easily insert only the outer needle 10 deep into the blood vessel 110.

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 movement without worrying about the index finger or palm touching the switch member 70.

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 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 located, and each constitutes the auxiliary inclined surface of the present invention.

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 easy to operate, but also has a high degree of freedom in operation.

Figures 8B to 8D are external oblique views showing modified examples of stopper 53d, with Figures 8B and C showing views from below and Figure 8D showing views from above.

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 in other parts, or may be provided only in one location or 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. 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.

Furthermore, in this case, the protrusion amount of the upper stopper 53d may be made smaller than the protrusion amount of the lower stopper 53d. In other words, the protrusion amount of the stopper 53d may vary depending on the circumferential position of the extension portion 53. For example, by reducing the protrusion amount of the stopper 53d close to the position of the user's fingertip, it is possible to improve operability and freedom of operation.

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 the amount of protrusion at which 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 greater than the amount of protrusion of the other portions. In other words, the amount of protrusion of the stopper 53d may be partially reduced in the circumferential direction to increase the area that can be pressed on the opening side end face 22 of the outer needle base 20.

The stopper 53d may also 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, while 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. It is also possible to make the inclined portion of the recess 53f form an auxiliary inclined surface.

In addition, although not shown in the figures, the shape of the stopper 53d is not particularly limited, and may be, for example, a rectangular column-shaped or cylindrical protrusion. The stopper 53d may be configured by eccentrically distributing the small diameter portion and the large diameter portion of the stepped cylinder. The stopper 53d is not limited to a surface that is approximately 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 the outer needle base 20. Specifically, the stopper 53d may be configured, for example, as a pyramidal or hemispherical protrusion, or the second outer diameter portion 53c may be partially tapered in the circumferential direction to expand the diameter in a tapered manner, or the inclination angle may be changed in the circumferential direction to expand the diameter in a tapered manner.

Next, we will explain 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 example are given the same reference numerals and their explanation will be omitted.

Figure 10A is a plan view (top view) of a modified example of the inner needle hub 40, Figure 10B is a side view of a modified example of the inner needle hub 40, and Figure 10C is a cross-sectional view of line IV-IV in Figure 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 way, it is possible to prevent the occurrence of sink marks and voids during injection molding while maintaining the strength of the inner needle fixing portion 41b, and improve moldability. In this example, a case where a recess 41c having a flat rectangular bottom surface is provided is shown, but the shape of the recess 41c may be other shapes. In addition, the number of recesses 41c is not limited.

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 opposing locations on the large diameter portion 42. The planar portions 42b are provided by cutting off a portion of the large diameter portion 42 substantially parallel to the axis. The distance between the two planar portions 42b is substantially equal to the outer diameter of the small diameter portion 41.

In this way, by providing the flat surface portion 42b on the approximately 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.

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

In this example, a generally funnel-shaped adhesive storage section 41d is provided on the inside of the inner needle fixing section 41b at the tip end side, and an outflow prevention section 41e with an inner diameter slightly larger than the outer diameter of the inner needle 30 is provided on the base end side. By configuring the inside of the inner needle fixing section 41b in this way, outflow of the adhesive to the base end side (outflow to the flash chamber section 47 described later) is prevented, and the inner needle 30 can be securely fixed. The outflow prevention section 41e is configured in a tapered shape that expands slightly toward the tip end side except for a part on the base end side, so that a small amount of adhesive also flows into the outflow prevention section 41e.

In addition, 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 arrangement part 48 in which the filter 43 is arranged is provided on the base end side. The inner diameter of the filter arrangement 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. In addition, the inner surface of the housing part 44 is smoothly continuous with the inner surface of the filter arrangement part 48, making it possible to smoothly insert the filter 43 from the base end side and arrange it in the filter arrangement part 48.

Figure 11A is a cross-sectional view taken along line IV-IV in Figure 10A, and shows 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 Figures 10A-C. 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.

In this way, by providing a flow passage 41f with a smaller diameter than the outflow prevention portion 41e, it is possible to more reliably prevent the adhesive from flowing out to the flash chamber portion 47. In addition, 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 the axial positioning of the inner needle 30.

Figure 11B is a side view showing a case where a friction part 90 is provided on the inner needle base 40 shown in Figures 10A to 10C. This friction part 90 is composed of a ring-shaped (annular) member fitted to the outer circumferential surface of the large diameter part 42 at a position axially adjacent to the force receiving part 45. This ring-shaped member is composed of an elastomer (elastic material) that is softer than the resin that constitutes the inner needle base 40, such as synthetic rubber. 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 base) 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 base 40 by contacting the inner circumferential surface of the housing 50 (base member 50a or inner needle housing member 50b) when the inner needle base 40 moves due to the biasing force of the biasing member 60.

Conventional indwelling needle assemblies have a problem in 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 splashed blood adheres to the user, etc.

11B is an embodiment of the present invention, which is intended to provide a safer indwelling needle assembly 1 in view of the above circumstances. In other words, by providing a friction portion 90, which is configured to generate a greater frictional force between the inner needle base 40 and the housing 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 housing 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.

The material of the friction part 90 is not particularly limited, and various known materials can be used. The shape of the friction part 90 is not particularly limited, and the friction part 90 may be configured so that the outer peripheral surface has an elliptical or polygonal shape when viewed from the axial direction. The surface (outer peripheral surface) of the friction part 90 that comes into contact with the housing 50 may be flat or curved. The surface of the friction part 90 that comes into contact with the housing 50 may be provided with protrusions or uneven shapes, and the friction part 90 may bite into the inner peripheral surface of the housing 50 to increase the frictional force.

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

11B, as described above, a ring-shaped member made of a flexible elastomer is fitted to 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 that the deceleration function is achieved.

Fig. 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. Note that Fig. 13B shows the base member 50a and the inner needle housing member 50b in an exploded state.

In this example, first, the portion of the second outer diameter portion 53c of the extension portion 53 that is further tip side than the stopper 53d is configured to have a tapered shape that corresponds 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, 51l are provided at the upper edge corners 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.

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. This makes it possible to prevent the occurrence of sink marks and voids during injection molding of the base member 50a and improve moldability.

In this example, anti-rotation grooves 54c are provided in two locations, 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.

In addition, chamfers 54d and 54e are provided at 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 and 54e, it is possible to prevent the small diameter portion 41 of the inner needle base 40 from getting caught when inserting it into the first inner diameter portion 54a, and to improve assembly.

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.

In addition, the inner needle housing 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 end side, and the main body portion 58 has both an outer diameter and an inner diameter smaller than the connected portion 57. By configuring the inner needle housing 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 housing member 50b toward the base member 50a and fit it into the base member 50a, thereby improving assembly. In addition, 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 housing member 50b.

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 on the tip side (the grip portion 51 side), 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.

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 approximately the same as the first support outer diameter portion 52b, and the inner diameter of the second support inner diameter portion 57c is set to be approximately the same as 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.

By configuring the connecting portion 52 and the connected portion 57 in this way, 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. Specifically, since the outer diameter of the second support outer diameter portion 52c is smaller than that of the first support inner diameter portion 57b, it is possible to facilitate the insertion of the connecting portion 52 into the connected portion 57 and to facilitate the elastic deformation when the first support inner diameter portion 57b overcomes the fitting outer diameter portion 52b. In addition, in a state in which 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 arranged at positions corresponding to each other, and the second support outer diameter portion 52c and the second support inner diameter portion 57c are arranged at positions corresponding to each other, so that a reliable connection with little rattle can be obtained.

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.

The above describes an embodiment of the present invention, but the indwelling needle assembly of the present invention is not limited to the above embodiment, and various modifications can of course be made without departing from the spirit and scope of the present invention.

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. In addition, 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. In addition, 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.

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.

REFERENCE SIGNS LIST 1 indwelling needle assembly 10 outer needle 20 outer needle base 30 inner needle 40 inner needle base 50 housing 51 gripping portion 51i rounded portion 53 extending portion 53b reduced diameter portion 53d stopper 60 biasing member 70 switch member 71 exposed portion 71a top surface 71b inclined surface

Claims (3)

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 arranged in the housing so as to be movable between a restricting position for restricting movement of the inner needle hub and a releasing position for releasing the restriction on the movement of the inner needle 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 . 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. 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.

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