WO2022191136A1 - Pharmaceutical liquid administration device - Google Patents

Abstract

A pharmaceutical liquid administration device (10) comprises an end cap (24) having a shaft (78) provided with a plurality of guide walls (78a). The plurality of guide walls (78a) include: first wall portions (79a) that extend in the axial direction; and second wall portions (79b) that are each wider in a width direction relative to the first wall portions (79a) and are provided in the vicinity of a tip-end of the shaft (78). A tip-end of a plunger rod (82) has second rod holes (100) through which the respective guide walls (78a) of the shaft (78) are inserted. When the shaft (78) is inserted in insertion grooves (101) of the second rod holes (100), the first wall portions (79a) are free of contact, whereas the second wall portions (79b) are in contact with retention walls (102a, 102b) to reduce the speed of movement of the plunger rod (82).

Description

Liquid dosing device

The present invention relates to a drug solution administration device that administers a drug solution into a punctured living body.

Conventionally, there has been known a portable medical solution administration device for puncturing the skin of a user (patient) to be administered and administering a medical solution used for subcutaneous injection. For example, as disclosed in Japanese Patent No. 6154061, such a drug delivery device includes a needle protection sleeve and a piston slidably provided in a casing, and a sleeve acting on the piston when discharging a drug solution. a shaped actuating member and a first spring acting on the actuating member. By bringing the tip of the needle protection sleeve into contact with the affected part, the casing moves toward the affected part, and the tip of the needle protrudes from the needle protection sleeve to puncture the affected part. After that, the actuating member is moved toward the tip side by the elastic force of the first spring, and the piston is pressed and moved toward the tip side accordingly, so that the drug solution in the product container is discharged from the needle and the affected area is discharged. administered subcutaneously.

In the above-described chemical liquid administration device, when the chemical liquid is not administered and in an unused state, the piston that seals the base end of the product container and the operating member are axially separated by a predetermined distance in consideration of manufacturing variations of each member. They are housed separately. Therefore, when the actuating member moves toward the distal end by the elastic force of the first spring, the distal end of the actuating member comes into contact with the proximal end of the piston after moving a predetermined distance in the axial direction. As a result, an impact is generated when the actuating member contacts the piston, and this impact is transmitted from the product container through the needle to the affected area. In addition, at the start of administration of the medical solution, the piston is rapidly pushed and moved toward the distal end side by the operating member, resulting in the rapid administration of the medical solution to the affected area.

A general object of the present invention is to provide a drug solution administration device that can mitigate the shock generated when the drug solution starts to be administered and can stably administer the drug solution.

An aspect of the present invention includes a housing formed in a hollow cylindrical shape, a cylinder housed in the housing and filled with a drug solution, and a syringe having a puncture needle that communicates with the cylinder and administers the drug solution into the living body. a hollow cylindrical needle cover that is provided inside the housing and that covers the distal end side of the syringe and that is relatively displaced in the proximal direction with respect to the housing by being pressed against the puncture target; a plunger that pushes a sealing member provided at the proximal end of the cylindrical body by moving the distal end thereof into the cylindrical body under the elastic action of the spring to eject the medical liquid from the puncture needle; A drug solution administration device for administration in vivo,
The housing and the plunger are provided with a speed reduction mechanism that reduces the movement speed of the plunger when it moves to the tip side, and the speed reduction mechanism reduces the movement speed of the plunger when it contacts the sealing body.

According to the present invention, the medicinal solution administration device includes a housing formed in a hollow cylindrical shape, and a plunger that moves inside the syringe under the repulsive action of a spring in the housing to eject the medicinal solution from the puncture needle. The housing and plunger are provided with a deceleration mechanism that decelerates the movement speed of the plunger when it moves to the distal end side.

Before the start of administration of the medicinal solution in which the spring elastic force applied to the plunger is large and the movement speed of the plunger is high, the movement speed of the plunger is reduced by the reduction mechanism, so that the plunger moves to the base of the cylinder. It is possible to mitigate the impact generated when contacting the sealing body provided at the end, and along with this, it is possible to avoid abrupt administration of the chemical solution at the start of the administration of the chemical solution, so that the chemical solution can be administered stably. It becomes possible to

1 is an external perspective view of a drug-solution administration device according to an embodiment of the present invention; FIG. 2 is an exploded perspective view of the drug-solution administration device shown in FIG. 1. FIG. FIG. 2 is an overall cross-sectional view of the drug-solution administration device shown in FIG. 1; 4 is an enlarged cross-sectional view showing the vicinity of the tip of the drug-solution administration device of FIG. 3; FIG. 4 is an enlarged cross-sectional view showing the vicinity of the proximal end of the drug-solution administration device of FIG. 3; FIG. 4 is a cross-sectional view taken along line VI-VI of FIG. 3; FIG. 4 is an overall cross-sectional view showing another cross-section in the medical-solution administration device of FIG. 3. FIG. 8 is an enlarged cross-sectional view showing the vicinity of the proximal end of the drug-solution administration device of FIG. 7; FIG. FIG. 9A is a partially cut-away enlarged perspective view showing a state in which the proximal end of the plunger rod is inserted into the guide groove of the end guide, and FIG. 9B is an operation explanatory diagram of the vicinity of the distal end of the plunger rod in FIG. 9A. 10A is a partially cut-away enlarged perspective view showing a state in which the plunger rod has started to rotate along the inclined guide portion, and FIG. 10B is an operation explanatory diagram of the vicinity of the tip of the plunger rod in FIG. 10A. FIG. 11A is a partially cut-away enlarged perspective view showing a state in which the plunger rod moves toward the tip side along the linear guide portion, and FIG. 11B is an operation explanatory view of the vicinity of the tip of the plunger rod in FIG. 11A. 2 is an external perspective view of an end cap that constitutes the drug-solution administration device of FIG. 1. FIG. 13 is an enlarged front view of the vicinity of the tip of the shaft portion in the end cap of FIG. 12; FIG. 4 is a cross-sectional view taken along line XIV-XIV in FIG. 3; FIG. 2 is a cross-sectional perspective view of a plunger rod that constitutes the drug-solution administration device of FIG. 1. FIG. FIG. 5 is an enlarged cross-sectional view showing a state in which the cap in the drug-solution administration device of FIG. 4 is pulled toward the distal end; 17 is a further enlarged cross-sectional view showing a state in which the base ends of the holding arms of the cap shown in FIG. 16 are tilted radially outward; FIG. FIG. 4 is an overall cross-sectional view showing a state in which a cap is removed from the medical-solution administration device of FIG. 3; 19 is an enlarged cross-sectional view showing the vicinity of the tip of the drug-solution administration device of FIG. 18; FIG. 19 is an enlarged cross-sectional view showing the vicinity of the proximal end of the drug-solution administration device of FIG. 18; FIG. FIG. 19 is an overall cross-sectional view showing a state where the medicinal-solution administration device of FIG. 18 starts to pierce the skin; 22 is an enlarged cross-sectional view showing the vicinity of the proximal end of the drug-solution administration device of FIG. 21; FIG. FIG. 22 is an overall cross-sectional view showing a state in which puncturing of the skin by the drug-solution administration device of FIG. 21 is completed; 24 is an enlarged cross-sectional view showing the vicinity of the proximal end of the drug-solution administration device of FIG. 23; FIG. FIG. 24 is an overall cross-sectional view showing another cross-section of the drug-solution administration device after puncturing of FIG. 23 is completed; 26 is an enlarged cross-sectional view showing the vicinity of the proximal end of the drug-solution administration device of FIG. 25; FIG. FIG. 26 is an overall cross-sectional view showing a state in which the plunger rod has started to move toward the distal end side in the drug-solution administration device of FIG. 25; 28 is an enlarged cross-sectional view showing the vicinity of the proximal end of the drug-solution administration device of FIG. 27; FIG. FIG. 28 is a cross-sectional view along line XXIX-XXIX in FIG. 27; FIG. 28 is an overall cross-sectional view showing a state in which the plunger rod has moved further to the distal end side in the medicinal-solution administration device of FIG. 27 and medicinal-solution administration has been completed; 31 is an enlarged cross-sectional view showing the vicinity of the proximal end of the plunger rod in the drug-solution administration device of FIG. 30; FIG. 31 is an overall cross-sectional view showing a state in which the plunger rod has moved further to the distal end side in the drug-solution administration device of FIG. 30 after drug-solution administration is completed; FIG. 33 is an overall cross-sectional view showing a state in which the puncture needle is moved to the proximal end side and accommodated in the cover sleeve in the medical-solution administration device of FIG. 32; FIG. 34 is an enlarged cross-sectional view showing the vicinity of the proximal end of the drug-solution administration device of FIG. 33; FIG.

This medical solution administration device 10 is used, for example, to subcutaneously administer a medical solution M to a patient (living body) who is a user, and as shown in FIGS. A housing 12 formed, a cover sleeve (needle cover) 14 movably housed inside the housing 12, a syringe 16 housed inside the cover sleeve 14, and a tip of the housing 12. and a cap 18 that is detachably provided with respect to.

The housing 12 is made of, for example, a resin material, and includes a cylindrical body 20 having a circular cross section and substantially constant outer diameter and inner diameter along the axial direction (directions of arrows A and B), and a base of the cylindrical body 20. It is composed of a sleeve body 22 accommodated on the end side (in the direction of arrow A) and an end cap 24 closing the proximal end of the cylindrical body 20 .

The cylindrical body 20 has a predetermined length in the axial direction (directions of arrows A and B), and both its distal end and proximal end are open. In addition, a confirmation window 26 is formed which is elongated along the axial direction. This confirmation window 26 is formed so as to penetrate the peripheral wall of the cylindrical body 20, and is opened corresponding to the position of the outer cylinder 124 of the syringe 16 accommodated therein, so that the medicinal solution M in the outer cylinder 124 can be seen. It is possible to confirm.

In addition, a pair of recesses 28 are formed at the tip of the cylindrical body 20 at positions facing holding arms 148 of the cap 18, which will be described later (see FIG. 4). For example, the concave portion 28 has a rectangular cross-section and is formed to be recessed in the radial direction with respect to the inner peripheral surface of the cylindrical body 20, and is formed with a predetermined length from the distal end toward the proximal end side (arrow A direction), They are formed in pairs at symmetrical positions with respect to the axis of the cylindrical body 20 . The concave portion 28 is arranged so as to face the holding arm 148 when the cap 18 is attached to the tip of the cylindrical body 20 .

The sleeve body 22 is formed in a hollow shape and has a body main body 30 formed in a cylindrical shape and an enlarged diameter portion 32 formed on the base end side (in the direction of arrow A) of the body main body 30. 30 is formed with a substantially constant diameter along the axial direction (directions of arrows A and B), and includes a plurality of guide ribs 34 protruding radially inward from the inner peripheral surface.

As shown in FIGS. 3, 5 and 6, the guide ribs 34 are, for example, provided at least three or more at equal intervals along the circumferential direction of the body main body 30, and have a substantially constant thickness along the inner periphery. They are formed in the same shape so that they linearly protrude radially inward from the surface and have the same protruding length in the radial direction from the inner peripheral surface. Here, four guide ribs 34 are arranged at intervals of 90° with respect to the axial center of the main body 30, and a set of guide ribs 34 are arranged so as to face each other with the axial center of the main body 30 interposed therebetween. A case will be described.

Moreover, as shown in FIG. 6, the guide ribs 34 have projections 36 protruding in the width direction orthogonal to their extending direction at the radially inner ends of the guide ribs 34. The projections 36 protrude to both sides in the width direction. At the same time, for example, they are each formed in a triangular cross-sectional shape that tapers gradually toward the tip in the width direction. The guide ribs 34 are movably guided along the axial direction (directions of arrows A and B) by being engaged with a plunger rod (plunger) 82 which will be described later.

Further, as shown in FIGS. 2, 3 and 5, a lock pin 44 and a plunger rod 82, which will be described later, are accommodated inside the sleeve body 22 so as to be axially movable, and are shown in FIGS. A plurality of protrusions 38 that protrude radially inward are formed at the boundary between the enlarged diameter portion 32 and the body main body 30 so as to be formed. The projecting portion 38 has a rectangular cross-section protruding from the inner peripheral surface of the main body 30 by a predetermined height, and has an arcuate cross-section when viewed from the axial direction of the sleeve body 22. The tapered surface gradually slopes toward the tip side (direction of arrow B) (see FIG. 8).

As shown in FIGS. 7 and 8, the projecting portion 38 is formed so that a collar portion 96 of a flexible portion 86 of a plunger rod 82, which will be described later, is engaged on the proximal end side (in the direction of arrow A). , the number and arrangement of which are set corresponding to the number and arrangement of the plurality of flexible portions 86 provided.

The sleeve body 22 is accommodated inside the open cylindrical body 20 from the base end side thereof, and the enlarged diameter portion 32 thereof is engaged with the inner peripheral portion of the cylindrical body 20 so that the enlarged diameter portion The base end of 32 is fixed in a state of being housed at a position on the tip side (in the direction of arrow B) from the base end of the cylindrical body 20 by a predetermined distance.

On the other hand, as shown in FIGS. 2, 3 and 5, the outer peripheral surface of the main body 30 is formed with a lock groove 40 recessed radially inward. are formed so as to form a pair at positions symmetrical to each other, and are formed so as to be engageable with a lock claw 62 of a lock pin 44, which will be described later.

A sleeve spring 42 made of a coil spring is inserted between the outer peripheral side of the main body 30 and the inner peripheral surface of the cylindrical body 20 . The base end of the sleeve spring 42 is engaged with the distal end of the enlarged diameter portion 32 , and the distal end thereof is engaged with the proximal end of a slide sleeve 64 , which will be described later, to separate the slide sleeve 64 from the sleeve body 22 . It biases toward the direction, ie, the tip side (arrow B direction).

Further, inside the sleeve body 22 described above, a lock pin 44 is accommodated so as to straddle the enlarged diameter portion 32 and the main body 30 .

The lock pin 44 is provided movably in the axial direction (directions of arrows A and B) inside the sleeve body 22, and has a cylindrical pin body 46 formed in the center and extending in the axial direction. and a pair of arm portions 48 provided on the outer peripheral side of the pin body 46. The arm portions 48 are integrally connected to the base end side of the pin body 46. As shown in FIG.

The pin body 46 includes a flat end wall portion 50 formed at the base end and orthogonal to the axial direction, a large diameter portion 52 extending from the center of the end wall portion 50 toward the tip side (in the direction of arrow B), and the A small-diameter portion 54 having a reduced outer diameter is formed on the distal end side (in the direction of arrow B) of the large-diameter portion 52, and a hole portion 56 formed in the center of the axis is formed by the end wall portion 50, the large-diameter portion 52, and the small-diameter portion 54. It penetrates through the small diameter portion 54 in a straight line. The hole portion 56 extends along the axial direction with an integral diameter, and the shaft portion 78 of the end cap 24 and an injection spring 58 to be described later are inserted therein.

The arm portion 48 has its base end connected to the end wall portion 50 of the pin body 46, is formed in parallel with the pin body 46 on the outer peripheral side with a predetermined space therebetween, and extends toward the tip side (in the direction of arrow B). , each extending with the same length. The distal end of the arm portion 48 has an engaging end 60 that engages with the base end of a slide sleeve 64 to be described later, and a lock claw 62 formed radially inward of the engaging end 60 .

The engaging end 60 is formed in a flat shape orthogonal to the extending direction of the arm portion 48, and the lock claw 62 protrudes radially inward from the engaging end 60 and toward the tip side (in the direction of arrow B). and has a triangular cross section that tapers toward the distal end side.

Further, inside the cylindrical body 20, a cylindrical slide sleeve 64 is provided on the tip side of the lock pin 44 (in the direction of the arrow B).

The slide sleeve 64 is provided movably in the axial direction (directions of arrows A and B) inside the cylindrical body 20, and the plunger rod 82 and the body main body 30 of the sleeve body 22 are inserted therein. The tip of the slide sleeve 64 has a receiving portion 66 that expands radially outward, and holds the tip of the sleeve spring 42 provided on the outer peripheral side. The slide sleeve 64 is biased toward the distal end (in the direction of arrow B) with respect to the end cap 24 . On the other hand, the proximal end of the slide sleeve 64 is provided so as to be able to engage with the engaging end 60 of the lock pin 44 arranged on the proximal side (in the direction of arrow A).

An end guide 68 is provided so as to face the tip of the slide sleeve 64. The end guide 68 is formed in a cylindrical shape having substantially the same diameter as the slide sleeve 64, and the plunger rod 82 moves in the axial direction inside the end guide 68. A guide groove 70 (see FIGS. 9A, 10A, and 11A) is formed on the inner peripheral surface of the plunger rod 82 so as to allow the plunger rod 82 to be freely inserted therethrough.

As shown in FIGS. 9A, 10A, and 11A, the guide groove 70 is recessed radially outward with respect to the inner peripheral surface of the end guide 68, and the collar portion 96 of the flexible portion 86 of the plunger rod 82, which will be described later, formed to be insertable; For example, four guide grooves 70 are provided at equal intervals in the circumferential direction corresponding to the number and arrangement of the flexible portions 86 .

Each guide groove 70 includes an inclined guide portion 72 inclined toward the distal end side (arrow B direction) with respect to the axial direction (arrows A and B directions) of the end guide 68 and The linear guide portion 74 extends linearly toward the distal end side, and the width dimension along the circumferential direction of the linear guide portion 74 is approximately the width dimension of the collar portion 96 of the plunger rod 82 to be described later. It is formed to be equal to or slightly larger.

As shown in FIGS. 2, 3, 5, and 12 to 14, the end cap 24 includes a lid portion 76 that closes the proximal end of the cylindrical body 20, and a distal end side (arrow B direction), and the lid portion 76 is formed in a disk shape with the same diameter as the outer diameter of the cylindrical body 20 .

The lid portion 76 has a pressing portion 80 protruding from the end face on the distal end side. By abutting on the proximal end, the movement of the sleeve body 22 housed inside the cylindrical body 20 toward the proximal end (in the direction of arrow A) is regulated and held.

The shaft portion 78 has a plurality of guide walls 78a having a cross-shaped cross section when viewed from the axial direction shown in FIGS. ) and is housed inside the cylindrical body 20 and the sleeve body 22 . The shaft portion 78 extends to the vicinity of the center in the axial direction of the cylindrical body 20 (see FIG. 3), and the injection spring 58 made of a coil spring and the plunger rod 82 are inserted through the outer peripheral side of the shaft portion 78 . In this embodiment, the case where the shaft portion 78 of the end cap 24 is provided with four guide walls 78a will be described.

The guide walls 78a are formed in a straight line along the axial direction (directions of arrows A and B), and are provided so as to be spaced equally apart from each other along the circumferential direction around the shaft portion 78, as shown in FIG. Seen from the axial direction of the end cap 24, the width dimension W1 (see FIG. 13) orthogonal to the direction in which the guide wall 78a protrudes radially outward is constant along the axial direction. and a second wall portion (contact portion) 79b provided in the vicinity of the tip of the shaft portion 78 and widened in the width direction with respect to the first wall portion 79a.

As shown in FIGS. 3, 5, 12, and 13, the second wall portion 79b is located at a predetermined distance from the distal end of the shaft portion 78 toward the proximal side (in the direction of arrow A in FIG. 13). It is provided in the middle of the first wall portion 79a and is evenly widened to both sides in the width direction with respect to the first wall portion 79a. , is connected to the first wall portion 79a via a tapered portion 79c that is gently inclined.

The tapered portion 79c is composed of an inclined surface that is inclined at a predetermined angle with respect to the axis of the shaft portion 78 . That is, the second wall portion 79b is formed so that the base end thereof gradually narrows and is connected to the first wall portion 79a (in the direction of arrow A).

In addition, the second wall portion 79b is provided at a position that is the same distance from the distal end to the proximal end along the axial direction of the four guide walls 78a.

The injection spring 58 is formed to be long corresponding to the axial length of the shaft portion 78, and is interposed between a plunger rod 82, which will be described later, and an end surface of the lid portion 76, and pushes the plunger rod 82 toward the tip side. urged towards.

When the end cap 24 is attached to the proximal end of the cylindrical body 20 , the open proximal end is closed with a lid portion 76 formed in a disc shape, and the shaft portion 78 is attached to the cylindrical body 20 . It is arranged so as to be on the axis.

As shown in FIGS. 2, 3, and 5 to 8, the plunger rod 82 is formed in an elongated cylindrical shape in the axial direction (directions of arrows A and B), and has a constant diameter along the axial direction. A rod main body 84 formed, a plurality of flexible portions 86 formed on the base end side (arrow A direction) of the rod main body 84 and divided in the circumferential direction, and a distal end side (arrow B direction) of the rod main body 84 and a mounting portion 90 to which a top member 88, which will be described later, is mounted.

The rod body 84 has a circular cross-section, and a plurality of slide grooves 92 are formed on the outer peripheral surface thereof so as to be recessed radially inward and into which the guide ribs 34 of the sleeve body 22 are inserted. As shown in FIG. 6, the slide grooves 92 are recessed, for example, in a rectangular cross-section with respect to the outer peripheral surface, and are provided at equal intervals in the circumferential direction corresponding to the number and arrangement of the guide ribs 34 . Here, a case where four slide grooves 92 corresponding to the guide ribs 34 are provided will be described.

When the plunger rod 82 is accommodated inside the sleeve body 22, the tip of each guide rib 34 is inserted into each slide groove 92 as shown in FIGS. Between the slide groove 92 and the tip of the guide rib 34, there is a first clearance Cr1 in the extending direction of the guide rib 34, and a second clearance Cr1 in the direction orthogonal to the extending direction. The second clearance Cr2 is the clearance between the protrusion 36 of the guide rib 34 and the inner surface of the slide groove 92 . That is, the first clearance Cr1 and the second clearance Cr2 are clearances positioned so as to be orthogonal to each other.

Further, inside the rod body 84, as shown in FIGS. 3 and 5 to 8, a first rod hole 94 extending along the axial direction (directions of arrows A and B) is formed to provide an end cap. 24 of the shaft portion 78 and the injection spring 58 are inserted.

The flexible portion 86 protrudes from the base end of the rod body 84 in the axial direction (direction of arrow A) by a predetermined length, and is provided so as to be spaced apart from each other in the circumferential direction between two adjacent slide grooves 92 . , and the base end (in the direction of arrow A) is provided so as to be tiltable in the radial direction with the tip end (in the direction of arrow B) connected to the rod body 84 as a fulcrum. A flange portion 96 projecting radially outward is formed at the proximal end of the flexible portion 86. The surface of the flange portion 96, which is the distal end side (in the direction of arrow B), gradually expands radially outward. is tapered toward the base end (see FIG. 8).

In addition, the flexible portion 86 is formed to expand radially outward with respect to the rod main body 84, and the small-diameter portion 54 of the lock pin 44 is formed therein so as to be insertable therein. That is, the inner peripheral diameter of the flexible portion 86 is formed to be larger than that of the first rod hole 94 .

Furthermore, as shown in FIG. 8, the outer diameter D1 of the collar portion 96 of the flexible portion 86 is slightly larger than the inner diameter D2 of the main body 30 of the sleeve body 22 (D1>D2).

2, 3, 5 and 7, the mounting portion 90 is formed to have a reduced diameter with respect to the rod body 84, and as shown in FIGS. 9B, 10B and 11B, its The outer peripheral surface is provided with a pair of engaging pieces 98 projecting radially outward and engaged with a top member 88 which will be described later. The engaging piece 98 extends in a horizontal direction orthogonal to the axial direction of the plunger rod 82 and is provided at a position symmetrical with respect to the axial center of the plunger rod 82 .

Further, inside the mounting portion 90, as shown in FIG. 5, a second rod hole (engagement hole) 100 extending along the axial direction (directions of arrows A and B) is formed. The second rod hole 100 has a substantially cross-shaped cross section through which the shaft portion 78 of the end cap 24 can be inserted when viewed from the axial direction of the plunger rod 82 shown in FIGS. It has four insertion grooves 101 which are formed to have a small diameter and through which the guide walls 78a of the shaft portion 78 are inserted, and holding walls (inner surfaces) 102a and 102b which form widthwise inner walls of the insertion grooves 101. ing.

The insertion grooves 101 are formed so as to protrude radially outward from the center of the second rod hole 100 with a substantially rectangular cross section when viewed from the axial direction of the plunger rod 82, and are arranged in a pair in the width direction substantially perpendicular to the projecting direction. holding walls 102a, 102b are provided. As shown in FIGS. 14 and 29, the width dimension W of the insertion groove 101 is set larger than the width dimension W1 of the first wall portion 79a of the guide wall 78a and smaller than the width dimension W2 of the second wall portion 79b. (W1<W<W2).

The pair of holding walls 102a and 102b are opposed to each other in the width direction with the insertion groove 101 interposed therebetween and substantially parallel to each other, and have a substantially triangular cross-sectional shape that gradually tapers inward in the radial direction. It is formed so as to have a symmetrical shape with the insertion groove 101 interposed therebetween.

In addition, in two adjacent insertion grooves 101, between the holding wall 102a of one insertion groove 101 and the holding wall 102b of the other insertion groove 101 adjacent in the circumferential direction of the second rod hole 100, there is a gap in the width direction. A space 103 is formed at a predetermined interval. That is, one holding wall 102a and the other holding wall 102b, which constitute two adjacent insertion grooves 101 and are adjacent to each other, are arranged so as to be spaced apart in the width direction.

Then, when the shaft portion 78 of the end cap 24 is inserted through the second rod hole 100, as shown in FIG. On the other hand, as shown in FIG. 29, when the second wall portion 79b is inserted through the holding walls 102a and 102b, the holding walls 102a and 102b come into surface contact and the holding walls 102a and 102b move outward in the width direction, i.e., the space portion. By being pressed to the 103 side, they tilt in the direction away from the second wall portion 79b. In other words, the holding wall 102a of one of the adjacent insertion grooves 101 and the holding wall 102b of the other insertion groove 101 are formed so as to be tiltable in a direction toward each other.

Further, as shown in FIGS. 3 and 5, the tip of the injection spring 58 is engaged with a stepped portion formed at the boundary between the second rod hole 100 and the first rod hole 94, so that the injection spring The elastic force of 58 acts to urge the plunger rod 82 away from the end cap 24, ie, to the tip side (arrow B direction).

As shown in FIGS. 2, 3, 5, 7, 9B, 10B, and 11B, the top member 88 is formed in a cup-like shape with an open base end (in the direction of arrow A) and serves as a plunger rod. A cylindrical cup portion 102 is provided on the base end side and is provided so as to be relatively rotatable with respect to the mounting portion 90 of 82 . The tip of the cup portion 102 of the top member 88 is provided so as to freely contact a gasket (sealing body) 106 made of an elastic material.

The mounting portion 90 of the plunger rod 82 is inserted into the cup portion 102 from the base end side, and a pair of engaging pieces 98 of the plunger rod 82 are inserted through the outer peripheral surface thereof in the radial direction. A guide groove 108 is formed.

The guide groove 108 is paired with a horizontal portion 110 formed in the vicinity of the proximal end of the cup portion 102 and extending along the circumferential direction. , and a vertical portion 112 extending from one end in the circumferential direction to the tip side (direction of arrow B) perpendicular to the horizontal portion 110 . A slanted portion 114 slanted at a predetermined angle is formed at the connecting portion of .

The top member 88 is axially connected by inserting the mounting portion 90 of the plunger rod 82 inside the cup portion 102 and inserting the engaging pieces 98 into the pair of guide grooves 108, respectively. It is provided so as to be integrally movable along the axial direction. 3 and 5, the tip of the top member 88 is arranged in the axial direction (arrow A and B directions) are accommodated in a state separated by a predetermined distance.

As shown in FIGS. 2 to 5 and 7, the cover sleeve 14 is movably provided inside a cylindrical body 20 that constitutes the housing 12, and has a cylindrical shape formed on the distal end side (in the direction of arrow B). and a pair of cover portions 118 extending from the sleeve body 116 toward the base end (in the direction of arrow A). The cover portion 118 is provided symmetrically about the axis of the cover sleeve 14 and extends a predetermined length along the axial direction.

Engagement holes 120 with which the holding arms 148 of the cap 18 are engaged are opened in the pair of cover portions 118 at positions on the sleeve body 116 side (in the direction of the arrow B). Long syringe guide holes 122 are opened along the axial direction on the base end side (in the direction of arrow A).

The engagement hole 120 is formed, for example, in a rectangular shape elongated in a direction orthogonal to the axial direction of the cover sleeve 14 and penetrates in the radial direction. The syringe guide hole 122 penetrates in the radial direction and is formed linearly along the axial direction, and is engaged with a syringe holder 130 described later so as to be axially movably engaged. That is, the syringe guide hole 122 has a guide function of guiding the syringe holder 130 in the axial direction.

The syringe 16 includes a hollow outer cylinder 124 filled with the liquid medicine M, a gasket 106 slidably inserted into the outer cylinder 124, and a tip end of the outer cylinder 124 ( and a protective cover 128 attached to the tip of the outer cylinder 124. The outer cylinder 124 is held by a cylindrical syringe holder 130 provided on the outer peripheral side thereof. be done. The medicinal solution M used is, for example, one used for subcutaneous injection of a patient.

The outer cylinder 124 is a hollow body that is formed in a substantially cylindrical shape and has an opening at its base end, and a flange 132 protruding radially outward is formed on the outer periphery of its base end. A needle holding portion 134 is provided at the distal end of the outer cylinder 124 , and the needle holding portion 134 has a reduced diameter relative to the outer cylinder 124 and protrudes in the distal direction to hold the proximal end of the puncture needle 126 .

In addition, the outer cylinder 124 is made of, for example, a transparent resin material, and the remaining amount of the chemical solution M filled inside can be visually recognized from the outside through the confirmation window 26 of the housing 12 . The flange 132 of the outer cylinder 124 is engaged with the proximal end of the syringe holder 130 so that the outer cylinder 124 is integrally held in a state where the outer peripheral side is covered without relative movement in the axial direction.

The gasket 106 is made of, for example, an elastic material such as rubber, is inserted into the outer cylinder 124 through the base end opening, and slides along the inner peripheral surface of the outer cylinder 124 in the axial direction. can be set freely. Also, the proximal end of the gasket 106 is formed flat so that the cup portion 102 of the top member 88 can come into contact with it when the plunger rod 82 moves. By inserting the gasket 106 into the outer cylinder 124 , the base end side of the outer cylinder 124 is liquid-tightly sealed, and the chemical solution M is sealed inside the outer cylinder 124 .

The puncture needle 126 is a hollow body having a channel through which the drug solution M flows. are in communication. Then, the medical solution M filled inside the outer cylinder 124 is discharged from the tip of the puncture needle 126 and administered to the patient.

As shown in FIGS. 2 to 4, the protective cover 128 is attached to the distal end of the outer cylinder 124 to cover the puncture needle 126. The protective cover 128 is made of an elastic material such as rubber and is attached to the needle holder 134. and an outer cover member 138 that covers the outer peripheral side of the needle shield 136 . The proximal end of the needle shield 136 is attached to the needle holding portion 134 so as to cover the puncture needle 126 , and an outer cover member 138 is fitted so as to be in sliding contact with the outer peripheral surface of the needle shield 136 . An annular groove 140 recessed radially inward is formed in the outer peripheral surface of the outer cover member 138, and a holding piece 152 of the cap 18, which will be described later, is engaged.

A syringe holder 130 for holding the syringe 16 is formed with a pair of protrusions 142 protruding radially outward from the outer peripheral surface. 130 is held movably along the axial direction (directions of arrows A and B) inside the cover sleeve 14 together with the syringe 16 .

The above-described syringe 16 is held by the syringe holder 130 and housed inside the cover sleeve 14 , with the puncture needle 126 facing the distal end (in the direction of arrow B) and the confirmation window 26 opening in the housing 12 . An outer cylinder 124 is arranged so as to face the outer cylinder 124, and the remaining amount of the chemical solution M in the outer cylinder 124 is accommodated in such a manner as to be visible from the outside.

As shown in FIGS. 1 to 4 and 16, the cap 18 has a bottom wall 144 formed at its distal end and an annular peripheral wall extending from the bottom wall 144 toward the base end (in the direction of arrow A). The peripheral wall 146 has a pair of holding arms 148 which are open at the proximal end and protrude axially (in the direction of arrow A) from the proximal end of the peripheral wall 146 .

As shown in FIGS. 2 to 4, 16 and 17, the holding arm 148 has a predetermined width in the circumferential direction of the cap 18 and is provided radially inward of the peripheral wall 146 so as to be in contact with the peripheral wall 146. It is provided so as to be able to tilt in the radial direction with the connecting portion as a fulcrum, and has an outer hook 150 protruding radially inward at its proximal end. The holding arms 148 are provided in pairs at symmetrical positions with respect to the axial center of the cap 18 .

When the cap 18 is attached to the distal end of the housing 12 , the proximal end of the peripheral wall 146 abuts the distal end of the cylindrical body 20 and the pair of holding arms 148 are positioned between the cylindrical body 20 and the cover sleeve 14 . The outer hook 150 of the holding arm 148 is engaged with the engaging hole 120 by being inserted into the gap and positioned to face the recess 28 and the engaging hole 120 .

As shown in FIG. 17, the axial length L1 of this engaging hole 120 is formed to be greater than the axial length L2 of the outer hook 150 (L1>L2). That is, the outer hook 150 is engaged with the engagement hole 120 so as to be movable in the axial direction (directions of arrows A and B).

In addition, in the state shown in FIG. 4 where the cap 18 is attached to the tip of the cover sleeve 14, the concave portion 28 is arranged so as to be offset from the engagement hole 120 to the tip side (in the direction of the arrow B), and the outer hook 150 is positioned. The base end of the holding arm 148 is arranged so as to be closer to the base end (in the direction of arrow A) than the base end of the recess 28 .

Furthermore, inside the cap 18, four holding pieces 152 projecting from the central portion of the bottom wall 144 toward the base end side (in the direction of arrow A) are provided. The holding piece 152 is formed in a substantially cylindrical shape that is divided from each other in the circumferential direction. A radially inwardly projecting inner hook 154 is engaged in the annular groove 140 of the outer cover member 138 .

As a result, the cap 18 is engaged with the protective cover 128 via the holding piece 152 and is also engaged with the tip of the cover sleeve 14 , thereby holding the protective cover 128 and holding the cover sleeve 128 . 14 and the tip of the housing 12 are covered.

The medicinal-solution administration device 10 according to the embodiment of the present invention is basically configured as described above, and its operation and effects will be described next.

First, the case where the medicinal solution administration device 10 with the cap 18 attached and in a pre-use state is accidentally dropped from the cap 18 side (front end side) onto the floor or the like will be described.

In the medicinal-solution administration device 10 shown in FIG. 3, for example, an impact due to contact with a floor surface or the like is transmitted to the cover sleeve 14, and the cover sleeve 14 moves from a predetermined position to the base end side (arrow A direction) (see the two-dot chain line shape in FIG. 4). In this case, as the cover sleeve 14 moves, the tip portion of the engaging hole 120 and the outer hook 150 of the holding arm 148 come into contact with each other, so that the base end side of the holding arm 148 including the outer hook 150 is moved. Although it is pressed radially outward, the recess 28 is not provided on the radially outer side of the base end of the holding arm 148 , and the radially outward tilting of the holding arm 148 causes the inner peripheral surface of the cylindrical body 20 to move. Regulated by

As a result, the medical-solution administration device 10 is dropped from the cap 18 side onto the floor or the like, and an impact force is applied to the cover sleeve 14 toward the proximal side (in the direction of arrow A), causing the cover sleeve 14 to move toward the proximal side. Since the engagement state of the holding arm 148 (the outer hook 150) with the engagement hole 120 is reliably maintained even when the cap 18 moves from the top of the housing 12 and the cover sleeve 14, It is securely held in a state of covering the tip of the housing 12 without being put away. Therefore, the puncture needle 126 housed inside the housing 12 and the cover sleeve 14 is prevented from being accidentally activated and exposed to the outside.

Next, when administering the medical solution M using the medical-solution administration device 10 described above, in the medical-solution administration device 10 in the state before use shown in FIGS. Remove the attached cap 18 . In this case, the patient grasps the cylindrical body 20 of the housing 12 and pulls the cap 18 away from the housing 12 (in the direction of arrow B), so that the cap 18 is removed as shown in FIG. It moves away from the tip of the cover sleeve 14 , and the outer hook 150 moves toward the tip (in the direction of arrow B) within the engagement hole 120 .

As a result, as shown in FIGS. 16 and 17, the outer hooks 150 face the recesses 28, and by pulling the cap 18 toward the distal end (in the direction of arrow B), the holding arms 148 and the outer hooks 150 are pulled. The holding arm 148 tilts radially outward under the action of contact with the distal end portion of the engaging hole 120 , and the proximal end side of the holding arm 148 having the outer hook 150 moves into the concave portion 28 . The engagement is released and then moves distally through the recess 28 and the gap between the cylindrical body 20 and the cover sleeve 14 .

As shown in FIGS. 18 and 19, as the cap 18 moves to the distal end side, the protective cover 128 held by the holding piece 152 moves together with the cap 18, whereby the outer cylinder 124 holds the needle. Exit from unit 134 . That is, by removing the cap 18 from the tip of the cover sleeve 14, the protective cover 128 of the syringe 16 can be removed at the same time.

Then, the engagement state of the cap 18 with respect to the cover sleeve 14 by the holding arm 148 is released and the cap 18 is completely removed from the tip of the cover sleeve 14, so that the housing 12 and the cover sleeve are separated as shown in FIGS. 14 is opened and the protective cover 128 covering the puncture needle 126 is removed at the same time.

Next, the medicinal solution M is administered using the medicinal solution administration device 10 from which the cap 18 has been removed as described above.

18 to 20, while the patient is holding the housing 12, the tip of the cover sleeve 14 protruding from the tip of the housing 12 is applied to the skin S, which is the desired puncture site. 21 and 22, the casing 12 is further pushed in toward the skin S side (front end side, arrow B direction). 23 and 24, the housing 12 moves toward the distal end side relative to the cover sleeve 14 while compressing the sleeve spring 42 toward the distal end side (in the direction of arrow B). go.

In addition, since the sleeve body 22 is in contact with the base end of the cover sleeve 14, it does not move relative to each other. never do.

Then, as shown in FIG. 23, the puncture needle 126 of the syringe 16 is exposed from the hole 14a of the cover sleeve 14 toward the tip side (in the direction of arrow B), and is inserted to a predetermined depth by puncturing the skin S. be. At this time, as shown in FIGS. 25 and 26, the plunger rod 82 is in a state in which the small-diameter portion 54 of the lock pin 44 is inserted inside the flexible portion 86, and the tilting movement inward in the radial direction is restricted. , the engagement state of the sleeve body 22 with the protrusion 38 is maintained, and relative movement with respect to the housing 12 is restricted, so that the sleeve body 22 moves integrally. In other words, the injection of the medical solution M by the plunger rod 82 is not yet performed.

As shown in FIG. 25, the pushing operation of the housing 12 toward the skin S moves the tip of the cylindrical body 20 to substantially the same position as the tip of the cover sleeve 14, and the puncture needle 126 is moved as described above. When the skin S is punctured to a predetermined depth, the puncture is completed.

25 and 26, when the puncture is completed, the lock pin 44 relatively moves toward the proximal side (in the direction of arrow A) as the housing 12 moves. , the small-diameter portion 54 of the lock pin 44 is separated from the inside of the flexible portion 86 of the plunger rod 82 toward the proximal end (in the direction of arrow A). The plunger rod 82 is urged toward the distal end (in the direction of arrow B) by the elastic force of the injection spring 58, and moves toward the distal end as shown in FIGS. The two flanges 96 are pushed radially inward under the action of contact between the tapered tip end surface and the projection 38, and each flexible portion 86 tilts radially inwardly with respect to the pin body 46. The portion 96 climbs over the protrusion 38 and moves to the tip side.

The plunger rod 82 moves toward the distal end (in the direction of arrow B) under the guidance of the guide ribs 34 of the sleeve body 22 inserted into the four slide grooves 92, and is inserted into the second rod hole 100. It moves axially without rotating under the guiding action of the shaft portion 78 . At this time, the plunger rod 82 moves while the first wall portion 79a of the shaft portion 78 is inserted through the second rod hole 100, and as shown in FIG. Since there is a clearance between the holding walls 102a and 102b of the groove 101, it does not slide and can move smoothly toward the tip side (in the direction of arrow B).

As shown in FIG. 6, when viewed from the axial direction of the plunger rod 82 and the sleeve body 22, between each guide rib 34 and each slide groove 92, there is a first clearance Cr1 in the extending direction of the guide rib 34. and a second clearance Cr2 in a direction orthogonal to the extending direction.

Specifically, in FIG. 6, if two guide ribs arranged in the left-right direction of the paper surface are designated as 34a, and two guide ribs arranged in the vertical direction of the paper surface are designated as 34b, the radial direction of the guide ribs 34a with respect to the slide groove 92 movement is restrained by the guide ribs 34b arranged orthogonally to the guide ribs 34a, while radial movement of the guide ribs 34b relative to the slide grooves 92 is restrained by the guide ribs 34a arranged orthogonally to the guide ribs 34b. In addition, since the width dimension along the width direction perpendicular to the extending direction of the guide ribs 34a and 34b can be set smaller than the diameter dimension of the piston in the drug-solution administration device according to the prior art, the dimensional tolerance is reduced as compared with the piston. can be suppressed to a small value, and along with this, radial positional variation (eccentricity) of the plunger rod 82 with respect to the sleeve body 22 is preferably suppressed.

Therefore, the eccentricity of the plunger rod 82 with respect to the sleeve body 22 is preferably suppressed, and the relative rotation of the plunger rod 82 with respect to the sleeve body 22 is also suppressed. As a result, the plunger rod 82 can be linearly moved toward the distal end side (in the direction of arrow B) while being maintained substantially coaxial with the housing 12 (sleeve body 22).

As described above, the plunger rod 82 moves toward the syringe 16, and as shown in FIG. When reaching the position, each insertion groove 101 of the second rod hole 100 moves from the tip of the first wall portion 79a of the shaft portion 78 to the tapered portion 79c, thereby forming a pair of insertion grooves 101. The tapered portion 79c comes into contact with the holding walls 102a and 102b, and the pair of holding walls 102a and 102b are gradually pushed away from each other (outward in the width direction, toward the space 103) by the tapered portion 79c. continue.

As a result, the holding walls 102a and 102b are pressed by the tapered portion 79c of the shaft portion 78, thereby increasing the contact area. increases, the moving speed of the plunger rod 82 toward the distal end (in the direction of arrow B) gradually decreases.

27 and 29, the second wall portion 79b wider than the tapered portion 79c is inserted through the insertion groove 101 of the second rod hole 100 by moving the plunger rod 82 further toward the distal end side. As a result, the pair of retaining walls 102a and 102b are further pushed outward in the width direction and tilted, and the contact area between the second wall portion 79b and the retaining walls 102a and 102b increases, thereby allowing the plunger rod 82 and the shaft to move. The sliding resistance between the portion 78 is further increased. As a result, the moving speed of the plunger rod 82 toward the distal end side (in the direction of arrow B) is further decelerated.

Since the width dimension W2 of the second wall portion 79b is substantially constant along the axial direction, the movement speed of the second wall portion 79b when it is inserted into the second rod hole 100 is substantially constant. .

In this way, the top member 88 at the tip of the plunger rod 82 abuts against the proximal end of the gasket 106 of the syringe 16 while the moving speed of the plunger rod 82 toward the tip side is reduced. As a result, when the top member 88 is brought into contact with the gasket 106 under the moving action of the plunger rod 82, the moving speed is reduced in advance, thereby suitably suppressing the impact generated at the time of contact.

Then, as shown in FIGS. 27 and 30, the movement of the plunger rod 82 toward the tip side (in the direction of arrow B) causes the gasket 106 to be inserted into the outer cylinder 124, and the chemical solution M in the outer cylinder 124 to be discharged. is pushed forward by the gasket 106 to be discharged from the puncture needle 126 and subcutaneously administered to the patient.

In addition, when the injection of the medical solution M is started with the movement of the plunger rod 82, the collar portion 96 of the plunger rod 82 has elasticity that urges it radially outward. After moving toward the distal end side (in the direction of arrow B) over the protrusion 38 of the sleeve body 22 , the outer edge portion expands radially outward again and contacts the inner peripheral surface of the main body 30 . At this time, since the outer diameter D1 of the collar portion 96 is slightly larger than the inner diameter D2 of the main body 30 of the sleeve body 22 (see FIG. 8), when the collar portion 96 contacts the main body 30, A first cognitive sound, which is a contact sound (hitting sound), is generated, and the patient can confirm that administration of the liquid medicine M has started by confirming this first cognitive sound.

After the injection of the medicinal solution M is started, the plunger rod 82 continues to move toward the distal end (in the direction of the arrow B) due to the repulsive force of the injection spring 58, and the second rod hole 100 is the shaft portion. 78 is moved to the tip side of the second wall portion 79b, and the first wall portion 79a is inserted again (see FIG. 14), thereby forming the second rod hole 100 and the first wall portion 79a. becomes non-contact and the sliding resistance is reduced. As a result, the deceleration of the plunger rod 82 is canceled and the plunger rod 82 smoothly moves toward the distal end side (in the direction of arrow B) again at a predetermined moving speed.

In addition, along with the movement of the plunger rod 82 , the medical solution M pushed out by the gasket 106 moving to the distal end side inside the outer cylinder 124 is discharged from the puncture needle 126 . This further distal movement of the plunger rod 82 causes its flexible portion 86 to reach the proximal end of the end guide 68, causing the collar 96 to contact the angled guide portion 72 as shown in FIG. 9A. Then, along the inclined guide portion 72, the collar portion 96 rotates clockwise and moves toward the distal end side (in the direction of arrow B). That is, by moving the plunger rod 82 along the inclined guide portion 72 of the end guide 68, a rotational force is applied to the plunger rod 82. As shown in FIG.

At the same time, as the plunger rod 82 rotates, the engagement piece 98 provided at the tip moves along the horizontal portion 110 in the guide groove 108 of the top member 88, as shown in FIG. 9B. As shown in FIG. 30, the plunger rod 82 reaches the tip of each guide rib 34 of the sleeve body 22 and is released from the axially guided state by the slide groove 92 and the guide ribs 34 and is in a rotatable state. .

As shown in FIG. 10A, when the flexible portion 86 rotates along the inclined guide portion 72 and moves toward the distal end side and reaches the linear guide portion 74, the plunger 86 moves toward the straight guide portion 74 as shown in FIG. A predetermined amount of the medicinal solution M in the outer cylinder 124 is administered to the skin S through the puncture needle 126 by the rod 82, and administration of the medicinal solution M is completed. Further, before the administration of the liquid medicine M described above is completed, the engaging piece 98 of the rotating plunger rod 82 reaches the inclined portion 114 of the guide groove 108 as shown in FIG. 10B. . As described above, the guide groove 70 functions as guide means for linearly moving the plunger rod 82 toward the distal end (in the direction of the arrow B) after rotating the plunger rod 82 by a predetermined amount.

After the administration of the medicinal solution M described above is completed, the engaging piece 98 of the plunger rod 82 moves toward the vertical portion 112 while rotating along the inclined portion 114 . 11B, the plunger rod 82 moves axially toward the tip end (in the direction of arrow B), and as shown in FIG. When the tip surface of the engaging piece 98 that has moved along the vertical portion 112 contacts the tip edge of the vertical portion 112, a second perceived sound, which is a contact sound (striking sound), is generated.

This second cognitive sound is generated with a predetermined delay after the administration of the medicinal solution M is completed, and the patient confirms that the administration of the medicinal solution to the affected area (skin S) is completed by the generation of the second cognitive sound. After confirming the second cognitive sound, the patient separates the drug-solution administration device 10 from the affected area.

That is, after the drug solution administration by the drug solution administration device 10 is completed, the top member connected to the plunger rod 82 is rotated by the guide groove 70 of the end guide 68 to reduce the moving speed in the axial direction. The time for the gasket 106 of 88 to reach the tip of the outer cylinder 124 is delayed, and a second recognition sound is generated to inform that the chemical solution administration is completed after a predetermined time has passed since the chemical solution administration is completed.

By releasing the pressing force on the skin S side of the drug-solution administration device 10, as shown in FIG. When the tip of the sleeve body 22 moves toward the tip side of the puncture needle 126, the puncture needle 126 is covered.

Also, as shown in FIGS. 33 and 34, the lock pin 44 moves toward the distal end (in the direction of arrow B) together with the cover sleeve 14, and its lock claw 62 engages the lock groove 40 of the sleeve body 22. As a result, the movement of the lock pin 44 in the axial direction with respect to the sleeve body 22 is restricted. The movement of the contacting cover sleeve 14 to the base end side (in the direction of arrow A) is also restricted.

As a result, as shown in FIGS. 33 and 34, the cover sleeve 14 completely covers the puncture needle 126 in the drug solution administration device 10 that has been removed from the skin S by the patient after the drug solution administration is completed. Since the movement of the sleeve 14 toward the base end side is restricted, the puncture needle 126 is not exposed outside by the cover sleeve 14 and is safe.

As described above, in the present embodiment, the end cap 24 that constitutes the housing 12 has the shaft portion 78 that extends axially toward the distal end side (the direction of the arrow B). A plunger rod 82 accommodated in the interior of the plunger 12 so as to be movable in the axial direction (directions of arrows A and B) has a second rod hole 100 through which the shaft portion 78 is inserted. The shaft portion 78 is provided with a plurality of guide walls 78a projecting radially outward and extending in the axial direction. , and a second wall portion 79b provided in the vicinity of the tip of the shaft portion 78 with a width dimension W2 widened in the width direction with respect to the first wall portion 79a.

When the plunger rod 82 moves toward the distal end (in the direction of arrow B) due to the elastic force of the injection spring 58, before the top member 88 provided at the distal end of the plunger rod 82 comes into contact with the gasket 106 of the syringe 16, , the second wall portion 79b is inserted into the insertion groove 101 of the second rod hole 100, so that the holding walls 102a and 102b of the insertion groove 101 slide on the second wall portion 79b, and accordingly, The moving speed of the plunger rod 82 toward the distal end side can be reduced.

As a result, while the moving speed of the plunger rod 82 is reduced, the top member 88 can be brought into contact with the gasket 106 and pressed toward the distal end side. ) can mitigate the impact that occurs when it abuts. In addition, since the administration speed of the medicinal solution M immediately after the start of administration can be suppressed and the administration can be stably performed, it is possible to alleviate the pain that is a concern when the medicinal solution M is suddenly administered to the affected area. Become.

In addition, the moving speed of the plunger rod 82 toward the distal end side can be reduced by a simple structure in which the shaft portion 78 constituting the end cap 24 is provided with the second wall portion 79b that is widened in the width direction with respect to the first wall portion 79a. It is possible to realize a deceleration mechanism capable of temporarily decelerating.

Further, in the second rod hole 100 through which the shaft portion 78 is inserted, a pair of holding walls 102a and 102b that are capable of tilting outward in the width direction under the contact action with the second wall portion 79b are provided. By tilting even when the insertion groove 101 is pressed by the portion 79b, the sliding resistance generated between the plunger rod 82 and the shaft portion 78 can be preferably adjusted.

It should be noted that the drug-solution administration device according to the present invention is not limited to the above-described embodiments, and can of course adopt various configurations without departing from the gist of the present invention.

Claims (4)

1. A housing formed in a hollow cylindrical shape, a cylinder housed in the housing and filled with a liquid medicine, a syringe having a puncture needle communicating with the cylinder and administering the liquid medicine into a living body, the housing a hollow cylindrical needle cover provided inside the housing to cover the distal end side of the syringe and displace relative to the housing in the proximal direction by being pressed against the puncture target; a plunger whose distal end moves into the cylindrical body under the elastic action of a spring to press a sealing member provided at the proximal end of the cylindrical body to eject the drug solution from the puncture needle; A drug solution administration device for administering the drug solution to a living body,
   The casing and the plunger are provided with a reduction mechanism that reduces the movement speed of the plunger when it moves to the tip end side, and the reduction mechanism reduces the movement speed of the plunger when it contacts the sealing body. A drug delivery device that slows down.
2. In the drug-solution administration device according to claim 1,
   the speed reduction mechanism includes a shaft portion extending in the moving direction of the plunger in the housing, and an engagement hole provided in the plunger through which the shaft portion is inserted,
   the shaft portion includes an insertion portion spaced apart from the inner surface of the engagement hole;
   a contact portion that slides on the inner surface of the engagement hole;
   A drug-solution administration device.
3. In the drug-solution administration device according to claim 2,
   The medical-solution administration device, wherein the contact portion is widened in a direction substantially orthogonal to the movement direction of the plunger with respect to the insertion portion.
4. The drug-solution administration device according to claim 2 or 3,
   The drug-solution administration device, wherein an inner surface of the engagement hole is provided with a retaining wall that is deformable under contact action with the contact portion.

Images