Liquid medicine administration device

Abstract

The drug solution administration device (10) includes at least three guide ribs (34) protruding radially inward from the inner peripheral surface of the sleeve body (22) and a plurality of slide grooves (92) formed on the outer peripheral surface of the plunger rod (82). The slide grooves (92) extend along the moving direction of the plunger rod (82) and receive the tips of the guide ribs (34). A first clearance (Cr1) is provided between the guide ribs (34) and the slide grooves (92) in the extending direction of the guide ribs (34), and a second clearance (Cr2) is provided in a direction perpendicular to the extending direction.

Description

Technical Field

[0001] The present invention relates to a chemical solution administration device for administering a chemical solution into a living body punctured by the chemical solution.

Background Art

[0002] Conventionally, a portable chemical solution administration device for puncturing the skin of a user (patient) as an administration target and administering a chemical solution used for subcutaneous injection has been known. Such a chemical solution administration device includes, for example, a needle protection sleeve and a piston slidably provided in a casing, a sleeve-shaped actuating member that acts on the piston when releasing the chemical solution, and a first spring that acts on the actuating member, as disclosed in Japanese Patent No. 6154061. Then, by bringing the tip of the needle protection sleeve into contact with the affected area, the casing moves toward the affected area side, and the tip of the needle protrudes from the needle protection sleeve to puncture the affected area. Thereafter, the piston moves in the axial direction by the elastic force of the first spring, so that the chemical solution in the product container is discharged from the needle and administered subcutaneously to the affected area.

[0003] Also, when the administration of the chemical solution is completed, the engagement state of the signal member with respect to the actuating member is released, so that the signal member moves in the direction opposite to the chemical solution administration direction by the spring force of the second spring disposed on the outer peripheral side of the first spring and abuts against a signal stopper provided at the base end portion of the casing. As a result, an auditory or tactile signal is transmitted, and it is confirmed that the administration of the chemical solution has been completed.

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a chemical solution administration device such as the above-mentioned Japanese Patent No. 6154061, the movement of the piston toward the tip side accompanying the axial movement of the needle protection sleeve serves as a trigger for starting the administration of the chemical solution or generating a signal. Therefore, the piston is required to have a stable movement along the axial direction inside the casing, and the radial eccentricity with respect to the casing is suppressed by controlling the diameter dimension of the piston.

[0005] However, the pistons described above are often molded products made of resin materials, and the diameter dimensions may vary due to shrinkage during molding, dimensional errors of the molding die, etc. Moreover, there is a limit to precisely controlling the diameter dimensions, and there is also a concern that the pistons may rotate in the circumferential direction with respect to the casing.

[0006] When radial displacement (eccentricity) or relative rotation in the circumferential direction of the piston with respect to the casing occurs as described above, the straightness during axial movement within the casing decreases and smooth movement cannot be achieved. Accordingly, there is a possibility that the start of administration of the chemical solution or the generation of a signal may be hindered.

[0007] A general object of the present invention is to provide a chemical solution administration device capable of stabilizing the operation by suppressing the eccentricity of the plunger with respect to the housing and enhancing the straightness.

[0008] An aspect of the present invention is a chemical solution administration device for administering a chemical solution into a living body, comprising: a housing formed in a hollow cylindrical shape; a cylinder accommodated in the housing and filled with the chemical solution, and a syringe having a puncture needle communicating with the cylinder for administering the chemical solution into the living body; a hollow cylindrical needle cover provided inside the housing, covering the tip side of the syringe, and relatively displaced in the proximal direction with respect to the housing by being pressed against the puncture target; a plunger provided inside the housing, the tip of which moves into the cylinder to discharge the chemical solution from the puncture needle; and a cap detachably provided at the tip of the needle cover and removed when the puncture needle punctures the puncture target. Either the inner peripheral surface of the housing or the outer peripheral surface of the plunger facing the inner peripheral surface is provided with a plurality of guide ribs protruding toward the other; The other of the inner peripheral surface of the housing and the outer peripheral surface of the plunger is provided with a guide groove in which at least a part of the guide rib is inserted and which extends along the moving direction of the plunger. At least three or more guide ribs are provided and formed along the axial direction. Between the guide ribs and the guide grooves, there are a first clearance provided in the extending direction of the guide ribs and a second clearance provided in a direction orthogonal to the extending direction.

[0009] According to the present invention, inside the housing constituting the chemical solution administration device, there is a plunger whose tip moves inside the syringe to discharge the chemical solution from the puncture needle. On either the inner peripheral surface of the housing or the outer peripheral surface of the plunger facing the inner peripheral surface, there are a plurality of guide ribs protruding toward the other. On the other of the inner peripheral surface of the housing and the outer peripheral surface of the plunger, there is a guide groove into which at least a part of the guide rib is inserted and which extends along the moving direction of the plunger. And at least three or more guide ribs are provided and formed along the axial direction. Between the guide ribs and the guide grooves, a first clearance is provided in the extending direction of the guide ribs, and a second clearance is provided in a direction orthogonal to the extending direction.

[0010] Therefore, inside the housing, when the plunger rod moves toward the tip side to discharge the chemical solution from the puncture needle, the plunger is guided along the guide rib inserted into the guide groove, so that the plunger does not rotate relative to the housing, and moreover, it can be moved linearly toward the tip side. Also, compared with the conventional chemical solution administration device that ensured straightness with respect to the casing by managing the diameter dimension of the piston, by reducing the width dimensions of the guide rib and the guide groove, dimensional tolerance can be suppressed, and eccentricity of the plunger in the radial direction with respect to the housing can be suppressed.

[0011] As a result, in the chemical solution administration device, by suppressing the eccentricity of the plunger with respect to the housing and enhancing straightness, it becomes possible to smoothly move the plunger toward the tip side and stably administer the chemical solution.

Brief Description of the Drawings

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Embodiments for Carrying Out the Invention

[0013] This chemical solution administration device 10 is used, for example, to administer a chemical solution M to the subcutaneous tissue of a patient who is the user. As shown in FIGS. 1 to 5, it includes a housing 12 formed in a hollow cylindrical shape, a cover sleeve (needle cover) 14 movably housed inside the housing 12, a syringe 16 housed inside the cover sleeve 14, and a cap 18 detachably provided at the tip of the housing 12.

[0014] The housing 12 is formed, for example, from a resin material, and includes a cylindrical body 20 having a circular cross-section and having an outer diameter and an inner diameter that are each substantially constant along the axial direction (arrow A, B directions), a sleeve body 22 housed on the proximal end side (arrow A direction) of the cylindrical body 20, and an end cap 24 closing the proximal end of the cylindrical body 20.

[0015] The cylindrical body 20 has a predetermined length in the axial direction (arrow A, B directions), and both its tip and proximal end are open. On its peripheral wall, a confirmation window 26 is formed that is provided slightly on the tip side from the axial center and that opens in a long shape along the axial direction. This confirmation window 26 is formed so as to penetrate the peripheral wall of the cylindrical body 20 and opens corresponding to the position of the outer cylinder 124 of the syringe 16 housed inside, making it possible to confirm the chemical solution M inside the outer cylinder 124.

[0016] Also, at the tip of the cylindrical body 20, a pair of recesses 28 are formed at positions facing the holding arms 148 of the cap 18 described later (see FIG. 4). The recesses 28 are formed, for example, with a rectangular cross-section and recessed radially with respect to the inner peripheral surface of the cylindrical body 20. They are formed with a predetermined length from the tip toward the base end side (in the direction of arrow A), and are formed symmetrically with respect to the axis of the cylindrical body 20. Then, when the cap 18 is attached to the tip of the cylindrical body 20, the recesses 28 are arranged to face the holding arms 148.

[0017] The sleeve body 22 is formed in a hollow shape and has a cylindrical body main body 30 and a diameter-expanded portion 32 formed on the base end side (in the direction of arrow A) of the body main body 30. The body main body 30 is formed with a substantially constant diameter along the axial direction (in the directions of arrows A and B), and a plurality of guide ribs 34 protruding radially inward from the inner peripheral surface are provided inside thereof.

[0018] As shown in FIGS. 3, 5, and 6, for example, the guide ribs 34 are spaced apart from each other at equal intervals along the circumferential direction of the body main body 30, at least three or more are provided, and they protrude linearly radially inward from the inner peripheral surface with a substantially constant thickness, and are formed in the same shape so that the protruding lengths in the radial direction from the inner peripheral surface are the same. Here, a case will be described in which four guide ribs 34 are arranged at every 90° with respect to the axis center of the body main body 30, and a set of guide ribs 34 are arranged to face each other across the axis center of the body main body 30.

[0019] Also, at the radially inner end of the guide rib 34, as shown in FIG. 6, there are protruding portions (protrusions) 36 protruding in the width direction orthogonal to the extending direction thereof. The protruding portions 36 protrude to both sides in the width direction and are each formed, for example, in a triangular cross-section that gradually tapers toward the tip in the width direction. The guide rib 34 is guided to be movable along the axial direction (in the directions of arrows A and B) by engaging with a plunger rod 82 described later.

[0020] Furthermore, as shown in FIGS. 2, 3, and 5, inside the sleeve body 22, a lock pin 44 and a plunger rod 82, which will be described later, are accommodated so as to be axially movable. As shown in FIGS. 7 and 8, at the boundary between the enlarged diameter portion 32 and the body main body 30, a plurality of protrusions 38 protruding radially inward are formed. The protrusion 38 is formed in a rectangular cross-sectional shape protruding a predetermined height from the inner peripheral surface of the body main body 30 and in an arc-shaped cross-section when viewed from the axial direction of the sleeve body 22, and its base end surface is a tapered surface inclined so as to gradually go toward the tip side (arrow B direction) toward the radially inner side (see FIG. 8).

[0021] As shown in FIGS. 7 and 8, the protrusion 38 is formed such that a flange portion 96 of a flexible portion 86 of the plunger rod 82, which will be described later, is engaged with the base end side (arrow A direction), and the quantity and arrangement thereof are set corresponding to the quantity and arrangement of the plurality of flexible portions 86 provided.

[0022] The sleeve body 22 is accommodated inside from the base end side of the open cylindrical body 20, and the enlarged diameter portion 32 thereof is engaged with the inner peripheral portion of the cylindrical body 20, so that the base end of the enlarged diameter portion 32 is accommodated in a state of being at a position a predetermined distance from the base end of the cylindrical body 20 toward the tip side (arrow B direction) and fixed.

[0023] On the other hand, as shown in FIGS. 2, 3, and 5, a lock groove 40 recessed radially inward is formed on the outer peripheral surface of the body main body 30. The lock groove 40 is formed so as to be symmetric with respect to the axial center of the sleeve body 22, and the lock claw 62 of the lock pin 44, which will be described later, can be engaged therewith.

[0024] Also, on the outer peripheral side of the body main body 30, a sleeve spring 42 made of a coil spring is inserted between the inner peripheral surface of the cylindrical body 20. The base end of the sleeve spring 42 is engaged with the tip of the enlarged diameter portion 32, and the tip is engaged with the base end of a slide sleeve 64, which will be described later, and biases the slide sleeve 64 in a direction away from the sleeve body 22, that is, toward the tip side (arrow B direction).

[0025] Furthermore, inside the sleeve body 22 described above, a locking pin 44 is accommodated so as to straddle the diameter-expanding portion 32 and the body main body 30.

[0026] This locking pin 44 is provided so as to be movable in the axial direction (directions of arrows A and B) inside the sleeve body 22, and has a pin main body 46 that is formed in the center, is cylindrical, and extends in the axial direction, and a pair of arm portions 48 provided on the outer peripheral side of the pin main body 46. The arm portions 48 are integrally connected to the base end side of the pin main body 46.

[0027] The pin main 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 (direction of arrow B), and a small-diameter portion 54 formed on the tip side (direction of arrow B) of the large-diameter portion 52 and having a reduced outer diameter. A hole portion 56 formed at the axial center penetrates the end wall portion 50, the large-diameter portion 52, and the small-diameter portion 54 in a straight line. The hole portion 56 has a uniform diameter and extends along the axial direction, and the shaft portion 78 of the end cap 24 and an injection spring 58 described later are inserted therein.

[0028] The arm portion 48 has its base end connected to the end wall portion 50 of the pin main body 46, is formed in parallel with a predetermined interval on the outer peripheral side with respect to the pin main body 46, and extends with the same length toward the tip side (direction of arrow B). At the tip of the arm portion 48, there are an engagement end 60 that engages with the base end of a slide sleeve 64 described later, and a locking claw 62 formed radially inward of the engagement end 60.

[0029] The engagement end 60 is formed in a flat shape orthogonal to the extending direction of the arm portion 48. The locking claw 62 is formed so as to project radially inward and toward the tip side (direction of arrow B) with respect to the engagement end 60, and is formed in a triangular cross-sectional shape that tapers toward the tip side.

[0030] Also, inside the cylindrical body 20, a cylindrical slide sleeve 64 is provided on the tip side (direction of arrow B) of the locking pin 44.

[0031] The slide sleeve 64 is provided so as to be movable axially (in the 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. And, the tip of the sleeve body 22 has a receiving portion 66 whose diameter expands radially outward, and the tip of the sleeve spring 42 provided on the outer peripheral side is held, so that the slide sleeve 64 is biased toward the tip side (in the direction of arrow B) with respect to the end cap 24 by the elastic force of the sleeve spring 42. On the other hand, the proximal end of the slide sleeve 64 is provided so as to be engageable with the engaging end 60 of the lock pin 44 disposed on the proximal end side (in the direction of arrow A).

[0032] Also, 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. The plunger rod 82 is inserted therein so as to be movable axially, and a guide groove 70 (see FIGS. 9A, 10A, and 11A) for rotating the plunger rod 82 is formed on the inner peripheral surface thereof.

[0033] 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 is formed so that the flange portion 96 of the flexible portion 86 of the plunger rod 82 described later can be inserted. For example, the guide grooves 70 are provided at four locations spaced equidistantly in the circumferential direction corresponding to the number and arrangement of the flexible portions 86.

[0034] Each guide groove 70 has an inclined guide portion 72 inclined toward the tip side (in the direction of arrow B) with respect to the axial direction (in the directions of arrows A and B) of the end guide 68, and a straight guide portion 74 extending linearly from the tip of the inclined guide portion 72 toward the tip side. The width dimension along the circumferential direction of the straight guide portion 74 is formed to be substantially equal to or slightly larger than the width dimension of the flange portion 96 of the plunger rod 82 described later.

[0035] As shown in FIGS. 2, 3, and 5, the end cap 24 has a lid portion 76 that closes the proximal end of the cylindrical body 20, and a shaft portion 78 that extends from the center of the lid portion 76 toward the distal end side (in the direction of arrow B). The lid portion 76 is formed in a disk shape with the same diameter as the outer diameter of the cylindrical body 20.

[0036] The lid portion 76 has a pressing portion 80 that protrudes from the end face on the distal end side. The pressing portion 80 is formed in an annular shape that protrudes a predetermined height from the end face, and by abutting against the proximal end of the enlarged diameter portion 32 of the sleeve body 22, it restricts and holds the movement of the sleeve body 22 accommodated inside the cylindrical body 20 toward the proximal end side (in the direction of arrow A).

[0037] The shaft portion 78 is composed of a shaft body that extends along the axial direction toward the distal end side (in the direction of arrow B). It is accommodated inside the cylindrical body 20 and the sleeve body 22, and extends to the vicinity of the axial center of the cylindrical body 20. An injection spring 58 made of a coil spring and a plunger rod 82 are inserted through the outer peripheral side thereof. The injection spring 58 is formed in a long shape corresponding to the axial length of the shaft portion 78, is interposed between the plunger rod 82 described later and the end face of the lid portion 76, and biases the plunger rod 82 toward the distal end side.

[0038] Then, by being attached to the proximal end of the cylindrical body 20, the end cap 24 closes the proximal end opened by the disk-shaped lid portion 76, and the shaft portion 78 is arranged on the axis of the cylindrical body 20.

[0039] As shown in FIGS. 2, 3, 5 to 8, the plunger rod (plunger) 82 is formed in a long cylindrical shape in the axial direction (in the directions of arrows A and B), and has a rod body 84 formed with a constant diameter along the axial direction, a plurality of flexible portions 86 formed on the proximal end side (in the direction of arrow A) of the rod body 84 and divided in the circumferential direction, and a mounting portion 90 formed on the distal end side (in the direction of arrow B) of the rod body 84 to which a top member 88 described later is mounted.

[0040] The rod body 84 is formed in a circular cross-section, and a plurality of slide grooves (guide grooves) 92 are formed on its outer peripheral surface, which are recessed radially inward for insertion of the guide ribs 34 of the sleeve body 22. As shown in FIG. 6, for example, the slide grooves 92 are recessed 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, the case where four slide grooves 92 corresponding to the guide ribs 34 are provided will be described.

[0041] When the plunger rod 82 is housed inside the sleeve body 22, as shown in FIGS. 5 and 6, the tips of the respective guide ribs 34 are inserted into the respective slide grooves 92. As shown in FIG. 6, between the slide grooves 92 and the tips of the guide ribs 34, there are respectively a first clearance Cr1 in the extending direction of the guide ribs 34 and a second clearance Cr2 in the direction orthogonal to the extending direction. The second clearance Cr2 is the clearance between the protruding portion 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 orthogonal to each other.

[0042] Also, inside the rod body 84, as shown in FIGS. 3, 5 to 8, a first rod hole 94 extending along the axial direction (arrow A, B directions) is formed, through which the shaft portion 78 of the end cap 24 and the injection spring 58 are inserted.

[0043] The flexible portion 86 protrudes from the base end of the rod body 84 by a predetermined length in the axial direction (arrow A direction), and is provided to be spaced apart from each other in the circumferential direction so as to be between two adjacent slide grooves 92. The base end side (arrow A direction) is provided to be tiltable in the radial direction with the tip side (arrow B direction) connected to the rod body 84 as a fulcrum. A flange portion 96 protruding radially outward is formed at the base end of the flexible portion 86, and the surface on the tip side (arrow B direction) of the flange portion 96 is formed in a tapered shape that gradually inclines toward the base end side with the radial direction outward (see FIG. 8).

[0044] Further, the flexible portion 86 is formed to have a diameter larger than that of the rod body 84 in the radial direction, and a small-diameter portion 54 of the lock pin 44 is formed to be insertable therein. That is, the inner peripheral diameter of the flexible portion 86 is formed to be larger than the diameter of the first rod hole 94.

[0045] Furthermore, as shown in FIG. 8, the outer diameter D1 of the flange portion 96 of the flexible portion 86 is formed to be slightly larger than the inner diameter D2 of the body main portion 30 of the sleeve body 22 (D1 > D2).

[0046] As shown in FIGS. 2, 3, 5, and 7, the mounting portion 90 is formed to have a diameter smaller than that of the rod body 84. As shown in FIGS. 9B, 10B, and 11B, a pair of engaging pieces 98 that protrude radially outward and engage with a top member 88 described later are provided on the outer peripheral surface thereof. The engaging pieces 98 extend in a horizontal direction orthogonal to the axial direction of the plunger rod 82 and are provided at positions symmetric with respect to the axial center of the plunger rod 82.

[0047] Also, as shown in FIG. 5, a second rod hole 100 extending along the axial direction (in the directions of arrows A and B) is formed inside the mounting portion 90. The second rod hole 100 is formed to have a smaller diameter than the first rod hole 94. The shaft portion 78 of the end cap 24 is inserted therethrough, and 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. Thereby, the elastic force of the injection spring 58 acts in a direction to separate the plunger rod 82 from the end cap 24, that is, to urge it toward the tip side (in the direction of arrow B).

[0048] As shown in FIGS. 2, 3, 5, 7, 9B, 10B, and 11B, the top member 88 is formed in a cup shape with an open base end side (in the direction of arrow A), and is provided so as to be relatively rotatable with respect to the mounting portion 90 of the plunger rod 82. The top member 88 includes a cylindrical cup portion 102 formed at the base end side and a mounting portion 104 protruding from the tip of the cup portion 102 toward the tip side (in the direction of arrow B). A gasket 106 made of an elastic material is mounted so as to cover the outer peripheral side of the mounting portion 104.

[0049] In the cup portion 102, the mounting portion 90 of the plunger rod 82 is inserted therein from the proximal end side, and a pair of guide grooves 108 that penetrate in the radial direction and through which the engaging pieces 98 of the plunger rod 82 are inserted are formed on the outer peripheral surface thereof.

[0050] The guide grooves 108 are provided so as to be symmetric with respect to a position symmetric with respect to the axial center of the cup portion 102, and include 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 that is orthogonal to the horizontal portion 110 and extends from one end in the circumferential direction to the distal end side (in the direction of arrow B). The guide grooves 108 are formed in a substantially L shape, and an inclined portion 114 inclined at a predetermined angle is formed at the connection portion between the horizontal portion 110 and the vertical portion 112.

[0051] Then, the top member 88 is inserted into the cup portion 102 with the mounting portion 90 of the plunger rod 82, and the engaging pieces 98 are respectively inserted into the pair of guide grooves 108 to be axially connected. The top member 88 is provided so as to be integrally movable along the axial direction, and with the gasket 106 mounted on the mounting portion 104, it is inserted into the outer cylinder 124 of the syringe 16 described later.

[0052] As shown in FIGS. 2 to 5 and FIG. 7, the cover sleeve 14 is movably provided inside the cylindrical body 20 constituting the housing 12, and has a cylindrical sleeve body 116 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 to the proximal end side (in the direction of arrow A). A hole portion 14a penetrating in the axial direction is opened at the center of the sleeve body 116, and the cover portions 118 are provided so as to be symmetric with respect to the axis of the cover sleeve 14 and extend along the axial direction for a predetermined length.

[0053] Further, engaging holes 120 into which the holding arms 148 of the cap 18 are engaged are respectively opened in the pair of cover portions 118 at positions on the sleeve body 116 side (in the direction of arrow B), and long syringe guide holes 122 extending along the axial direction are respectively opened on the proximal end side (in the direction of arrow A) of the engaging holes 120.

[0054] The engaging hole 120 is formed, for example, in a rectangular shape that is long 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 a syringe holder 130 described later is engaged so as to be movable in the axial direction. That is, the syringe guide hole 122 has a guide function of guiding the syringe holder 130 in the axial direction.

[0055] The syringe 16 includes a hollow outer cylinder 124 filled with a chemical solution M therein, a gasket 106 slidably inserted inside the outer cylinder 124, a puncture needle 126 provided at the tip of the outer cylinder 124 and protruding in the tip direction (arrow B direction), 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. Note that, as the chemical solution M to be used, there is, for example, one used for subcutaneous injection of a patient.

[0056] The outer cylinder 124 is a hollow body formed in a substantially cylindrical shape and having an opening at the base end, and a flange 132 protruding radially outward is formed on the outer peripheral portion of the base end thereof. A needle holding portion 134 is provided at the tip of the outer cylinder 124. The needle holding portion 134 has a reduced diameter with respect to the outer cylinder 124 and protrudes in the tip direction to hold the base end of the puncture needle 126.

[0057] Further, the outer cylinder 124 is formed of, for example, a transparent resin material, and the remaining amount of the chemical solution M filled therein can be visually recognized from the outside through the confirmation window 26 of the housing 12. The outer cylinder 124 is integrally held in a state where the outer peripheral side is covered without relative movement in the axial direction by engaging the flange 132 thereof with the base end of the syringe holder 130.

[0058] The gasket 106 is formed of an elastic material such as rubber, and is inserted into the interior through the proximal opening of the outer cylinder 124 while being attached to the attachment portion 104 of the top member 88, and is provided slidably in the axial direction along the inner peripheral surface of the outer cylinder 124. When the gasket 106 is inserted into the interior of the outer cylinder 124, the proximal end side of the outer cylinder 124 is sealed liquid-tightly and the chemical solution M is enclosed in the interior of the outer cylinder 124.

[0059] The puncture needle 126 is a hollow body having a flow path through which the chemical solution M flows inside, projects from the needle holding portion 134 toward the tip, and its flow path communicates with the interior of the outer cylinder 124 filled with the chemical solution M. Then, the chemical solution M filled in the interior of the outer cylinder 124 is discharged from the tip of the puncture needle 126 and administered to the patient.

[0060] As shown in FIGS. 2 to 4, the protective cover 128 is attached to the tip of the outer cylinder 124 to cover the puncture needle 126, is made of an elastic material such as rubber, and includes a needle shield 136 attached to the needle holding portion 134 and an outer cover member 138 covering the further outer peripheral side of the needle shield 136. Then, 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 the outer cover member 138 is fitted so as to be in sliding contact with the outer peripheral surface of the needle shield 136. Further, an annular groove 140 recessed radially inward is formed on the outer peripheral surface of the outer cover member 138, and a holding piece 152 of a cap 18 described later is engaged therewith.

[0061] The syringe holder 130 that holds the syringe 16 is formed with a pair of convex portions 142 protruding radially outward from the outer peripheral surface, and by being inserted into the syringe guide holes 122 of the cover sleeve 14 respectively, the syringe holder 130 is held movably along the axial direction (in the directions of arrows A and B) inside the cover sleeve 14 together with the syringe 16.

[0062] The above-described syringe 16 is held by the syringe holder 130 and housed inside the cover sleeve 14. In this state, the puncture needle 126 is on the tip side (in the direction of arrow B), and the outer cylinder 124 is arranged so as to face the confirmation window 26 that opens to the housing 12. The remaining amount of the chemical solution M in the outer cylinder 124 is housed in a state where it can be visually recognized from the outside.

[0063] As shown in FIGS. 1 to 4 and FIG. 12, the cap 18 is formed in a bottomed cylindrical shape having a bottom wall 144 formed at its tip and an annular peripheral wall 146 standing upright from the bottom wall 144 toward the base end side (in the direction of arrow A). The base end side is open, and it is provided with a pair of holding arms 148 protruding in the axial direction (in the direction of arrow A) from the base end of the peripheral wall 146.

[0064] As shown in FIGS. 2 to 4, FIG. 12, and FIG. 13, the holding arm 148 has a predetermined width in the circumferential direction of the cap 18 and is provided radially inside the peripheral wall 146. It is provided so as to be tiltable in the radial direction with the connection part with the peripheral wall 146 as a fulcrum, and its base end is provided with an outer hook 150 protruding radially inward. Also, the holding arms 148 are provided so as to be symmetric with respect to positions sandwiching the axial center of the cap 18.

[0065] When the cap 18 is attached to the tip of the housing 12, the base end of the peripheral wall 146 abuts against the tip of the cylindrical body 20, and the pair of holding arms 148 are inserted into the gap between the cylindrical body 20 and the cover sleeve 14 and arranged at positions facing the recess 28 and the engagement hole 120. Thus, the outer hook 150 of the holding arm 148 is engaged with the engagement hole 120.

[0066] As shown in FIG. 13, the axial length L1 of this engagement hole 120 is formed larger 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 in a state where it can move in the axial direction (in the directions of arrows A and B).

[0067] Also, in the state where the cap 18 is attached to the tip of the cover sleeve 14 shown in FIG. 4, the recess 28 is arranged to be offset toward the tip side (in the direction of arrow B) from the engagement hole 120, and the proximal end of the holding arm 148 having the outer hook 150 is arranged to be on the proximal end side (in the direction of arrow A) of the proximal end of the recess 28.

[0068] Furthermore, inside the cap 18, four holding pieces 152 protruding from the central portion of the bottom wall 144 toward the proximal end side (in the direction of arrow A) are provided. The holding pieces 152 are formed in a substantially cylindrical shape divided from each other in the circumferential direction, and when the outer cover member 138 of the protective cover 128 constituting the syringe 16 is inserted therein, the inner hook 154 protruding radially inward formed at the proximal end of the holding piece 152 is engaged with the annular groove 140 of the outer cover member 138.

[0069] Thereby, the cap 18 is engaged with the protective cover 128 via the holding pieces 152 and is engaged with the tip of the cover sleeve 14, and is attached so as to cover the tips of the cover sleeve 14 and the housing 12 while holding the protective cover 128.

[0070] The chemical solution administration device 10 according to the embodiment of the present invention is basically configured as described above, and next, its operation and effects will be described.

[0071] First, a case where the chemical solution administration device 10 with the cap 18 attached and in a state before use is accidentally dropped onto the floor or the like from the cap 18 side (tip side) will be described.

[0072] In the chemical solution administration device 10 shown in FIG. 3, for example, an impact caused by contact with a floor surface or the like may be transmitted to the cover sleeve 14, and the cover sleeve 14 may move relative to the housing 12 from a predetermined position toward the proximal end side (in the direction of arrow A) (refer to the two-dot chain line shape in FIG. 4). In this case, as the cover sleeve 14 moves, the tip portion of the engagement hole 120 and the outer hook 150 of the holding arm 148 come into contact with each other, and the proximal end side of the holding arm 148 including the outer hook 150 is pressed radially outward. However, a recess 28 is not provided on the radially outer side of the proximal end of the holding arm 148, and the tilting of the holding arm 148 radially outward is restricted by the inner peripheral surface of the cylindrical body 20.

[0073] As a result, even when the chemical solution administration device 10 is dropped onto a floor surface or the like from the cap 18 side and an impact force in the proximal end side direction (in the direction of arrow A) is applied to the cover sleeve 14 and the cover sleeve 14 moves toward the proximal end side, the engagement state of the holding arm 148 (outer hook 150) with respect to the engagement hole 120 is surely maintained. Therefore, the cap 18 does not come off from the tips of the housing 12 and the cover sleeve 14 and is surely held in a state of covering the tip of the housing 12. Therefore, it is possible to prevent the puncture needle 126 housed inside the housing 12 and the cover sleeve 14 from malfunctioning and being exposed to the outside.

[0074] Next, when administering a chemical solution with the above-described chemical solution administration device 10, in the chemical solution administration device 10 in the state before use shown in FIGS. 3 and 4, the cap 18 attached to the tips of the housing 12 and the cover sleeve 14 is removed. In this case, the patient grips the cylindrical body 20 of the housing 12 and pulls the cap 18 in a direction away from the housing 12 (in the direction of arrow B). As a result, as shown in FIG. 12, the cap 18 moves so as to be separated from the tip of the cover sleeve 14, and its outer hook 150 moves toward the tip side (in the direction of arrow B) within the engagement hole 120.

[0075] As a result, as shown in FIGS. 12 and 13, the outer hook 150 comes to a position facing the recess 28. Further, by pulling the cap 18 toward the tip side (in the direction of arrow B), the holding arm 148 tilts radially outward under the contact action between the outer hook 150 and the tip of the engagement hole 120. The proximal end side of the holding arm 148 having the outer hook 150 moves into the recess 28, thereby releasing the engagement state with respect to the engagement hole 120. Thereafter, it moves toward the tip side through the gap between the recess 28, the cylindrical body 20, and the cover sleeve 14.

[0076] Then, as shown in FIGS. 14 and 15, as the cap 18 moves toward the tip side, the protective cover 128 held by the holding piece 152 moves together with the cap 18 and detaches from the needle holding portion 134 of the outer cylinder 124. 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 simultaneously removed.

[0077] Then, the engagement state of the cap 18 with respect to the cover sleeve 14 by the holding arm 148 is released. By completely removing it from the tip of the cover sleeve 14, as shown in FIGS. 14 and 15, the tips of the housing 12 and the cover sleeve 14 are opened, and the protective cover 128 that covered the puncture needle 126 is simultaneously removed.

[0078] Next, the chemical solution M is administered using the chemical solution administration device 10 from which the cap 18 has been removed as described above.

[0079] First, with the patient holding the housing 12, the tip of the cover sleeve 14 protruding from the tip of the housing 12 of the chemical solution administration device 10 shown in FIGS. 14 to 16 is pressed against the skin S at a desired puncture site so as to be substantially perpendicular. Then, as shown in FIGS. 17 and 18, the housing 12 is further pushed toward the skin S side (tip side, in the direction of arrow B). As a result, as shown in FIGS. 19 and 20, the housing 12 moves relatively toward the tip side with respect to the cover sleeve 14 while compressing the sleeve spring 42 toward the tip side (in the direction of arrow B).

[0080] Further, since the sleeve body 22 abuts against the proximal end of the cover sleeve 14, they do not move relative to each other. Similarly, the lock pin 44 also abuts against the proximal end of the sleeve body 22 and thus does not move toward the distal end side.

[0081] Then, as shown in FIG. 19, when the puncture needle 126 of the syringe 16 is exposed from the hole 14a of the cover sleeve 14 toward the distal end side (in the direction of arrow B), it punctures the skin S and is inserted to a predetermined depth. At this time, as shown in FIGS. 21 and 22, the small-diameter portion 54 of the lock pin 44 is inserted inside the flexible portion 86 of the plunger rod 82. Since the tilting inward in the radial direction is restricted, the engagement state with respect to the protrusion 38 of the sleeve body 22 is maintained, and the relative movement with respect to the housing 12 is restricted, so they move integrally. That is, the administration of the chemical solution M by the plunger rod 82 has not been performed yet.

[0082] By pushing the housing 12 toward the skin S side in this way, as shown in FIG. 21, the distal end of the cylindrical body 20 moves until it is substantially at the same position as the distal end of the cover sleeve 14, and the puncture needle 126 punctures the skin S to a predetermined depth and the puncture is completed.

[0083] At the end of the puncture in this way, as shown in FIGS. 21 and 22, as the housing 12 moves, the lock pin 44 moves relatively toward the proximal end side (in the direction of arrow A), and accordingly, the small-diameter portion 54 of the lock pin 44 disengages from the inside of the flexible portion 86 of the plunger rod 82 toward the proximal end side (in the direction of arrow A). Then, the plunger rod 82 is biased toward the distal end side (in the direction of arrow B) by the elastic force of the injection spring 58, and as shown in FIGS. 23 and 24, by moving toward the distal end side, the four flange portions 96 are pushed radially inward under the contact action between the tapered tip surface and the protrusion 38, and each flexible portion 86 tilts radially inward with respect to the pin body 46, and the flange portions 96 move over the protrusion 38 and toward the distal end side.

[0084] Further, the plunger rod 82 moves axially without rotating toward the tip side under the guiding action of each guide rib 34 of the sleeve body 22 inserted into the four slide grooves 92, and the gasket 106 attached to the top member 88 at the tip is inserted into the outer cylinder 124 of the syringe 16.

[0085] At this time, as shown in FIG. 6, when viewed axially of the plunger rod 82 and the sleeve body 22, there is a first clearance Cr1 in the extending direction of the guide rib 34 and a second clearance Cr2 in the direction orthogonal to the extending direction between each guide rib 34 and each slide groove 92.

[0086] Specifically, in FIG. 6, if the two guide ribs arranged in the left - right direction of the drawing are 34a and the two guide ribs arranged in the up - down direction of the drawing are 34b, the radial movement of the guide rib 34a with respect to the slide groove 92 is suppressed by the guide rib 34b arranged orthogonally to the guide rib 34a. On the other hand, the radial movement of the guide rib 34b with respect to the slide groove 92 is suppressed by the guide rib 34a arranged orthogonally to the guide rib 34b. Further, since the width dimension along the width direction orthogonal to the extending direction of the guide ribs 34a and 34b can be set smaller than the diameter dimension of the piston in the chemical liquid administration device according to the prior art, it is possible to suppress the dimensional tolerance to be smaller compared with the piston. Along with this, the radial position variation (eccentricity) of the plunger rod 82 with respect to the sleeve body 22 is preferably suppressed.

[0087] Therefore, the eccentricity of the plunger rod 82 with respect to the sleeve body 22 is preferably suppressed, and moreover, the relative rotation of the plunger rod 82 with respect to the sleeve body 22 is also suppressed. As a result, it becomes possible to linearly move the plunger rod 82 toward the tip side (arrow B direction) while maintaining it substantially coaxially with respect to the housing 12 (sleeve body 22).

[0088] Then, as shown in FIGS. 25 and 26, as the plunger rod 82 moves toward the tip side (in the direction of arrow B), the chemical solution M in the outer cylinder 124 is pressed toward the tip side by the gasket 106, discharged from the puncture needle 126, and administered subcutaneously to the patient.

[0089] Also, when the administration of the chemical solution M is started as the plunger rod 82 moves, since the flange portion 96 of the plunger rod 82 has elasticity that biases it radially outward, after getting over the protrusion 38 of the sleeve body 22 shown in FIG. 24 and moving toward the tip side (in the direction of arrow B), it expands radially outward again and the outer edge portion comes into contact with the inner peripheral surface of the body main body 30. At this time, since the outer diameter D1 of the flange portion 96 is formed to be slightly larger than the inner diameter D2 of the body main body 30 in the sleeve body 22 (see FIG. 8), a first recognition sound, which is a contact sound (a hitting sound), is generated when the flange portion 96 comes into contact with the body main body 30, and by confirming this first recognition sound, the patient can confirm that the administration of the chemical solution M has started.

[0090] After the administration of the chemical solution M is started, the plunger rod 82 continues to move continuously at a constant speed toward the tip side (in the direction of arrow B) by the elastic force of the injection spring 58, and the chemical solution M extruded by the gasket 106 moving toward the tip side in the outer cylinder 124 is discharged from the puncture needle 126. As the plunger rod 82 moves further toward the tip side, its flexible portion 86 reaches the base end of the end guide 68, and as shown in FIG. 9A, when the flange portion 96 comes into contact with the inclined guide portion 72, the flange portion 96 moves toward the tip side (in the direction of arrow B) while rotating clockwise along the inclined guide portion 72. 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.

[0091] At the same time, as the plunger rod 82 rotates, as shown in FIG. 9B, the engaging 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. 25, the plunger rod 82 reaches the tip of each guide rib 34 of the sleeve body 22, and the axial guiding state by the slide groove 92 and the guide rib 34 is released and it is in a rotatable state.

[0092] As shown in FIG. 10A, when this flexible portion 86 moves to the tip side while rotating along the inclined guide portion 72 and reaches the linear guide portion 74, as shown in FIG. 27, the chemical solution M in the outer cylinder 124 is administered to the skin S through the puncture needle 126 by a preset predetermined amount by the plunger rod 82, and the administration of the chemical solution M ends. Also, before the administration of the chemical solution M described above ends, 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 a guide means for linearly moving the plunger rod 82 in the tip side (arrow B direction) after rotating the plunger rod 82 by a predetermined amount.

[0093] After the administration of the chemical solution M described above ends, the engaging piece 98 of the plunger rod 82 moves toward the vertical portion 112 while rotating along the inclined portion 114, and is guided and moves to the tip side along the vertical portion 112. This plunger rod 82 moves axially again toward the tip side (arrow B direction), and as shown in FIG. 11B, when the tip surface of the engaging piece 98 that has moved along the vertical portion 112 of the guide groove 108 contacts the tip edge of the vertical portion 112, a second confirmation sound that is a contact sound (striking sound) is generated.

[0094] This second confirmation sound is generated with a predetermined time delay after the administration of the chemical solution M ends. By the generation of the second confirmation sound, the patient can confirm that the administration of the chemical solution to the affected part (skin S) has ended. After confirming the second confirmation sound, the patient separates the chemical solution administration device 10 from the affected part.

[0095] That is, after the administration of the chemical solution by the chemical solution administration device 10 is completed, the plunger rod 82 is rotated by the guide groove 70 of the end guide 68 to reduce the axial movement speed, thereby delaying the time for the gasket 106 of the top member 88 connected to the plunger rod 82 to reach the tip of the outer cylinder 124. After a predetermined time has elapsed since the completion of the chemical solution administration, a second confirmation sound for notifying that the chemical solution administration has ended is generated.

[0096] Further, as in the plunger rod 82a shown in FIGS. 28 to 29B, two first and second contact ribs 156a and 156b may be provided on the outer peripheral surface of the flexible portion 86, extending axially from the flange portion 96 toward the tip side (in the direction of arrow B), and protruding radially outward from the outer peripheral surface. The length of the first contact rib 156a is formed shorter than the length of the second contact rib 156b so that the tip of the first contact rib 156a is closer to the flange portion 96 than the tip of the second contact rib 156b, and the second contact rib 156b is provided at a predetermined interval in a position in the rotational direction of the plunger rod 82a with respect to the first contact rib 156a and is substantially parallel. Note that the number of contact ribs is not limited to two.

[0097] Thereby, as shown in FIG. 29A, as the tip side (in the direction of arrow B) of the plunger rod 82a moves, the tips of the first and second contact ribs 156a and 156b reach the base end of the end guide 68 and the tips contact the inclined guide portion 72 of the guide groove 70, so that the plunger rod 82a including the first and second contact ribs 156a and 156b can be moved toward the tip side (in the direction of arrow B) while rotating clockwise along the inclined guide portion 72 (see FIG. 29B).

[0098] That is, by moving the first and second contact ribs 156a and 156b along the inclined guide portion 72 of the end guide 68, it becomes possible to apply a rotational force to the plunger rod 82a. Note that a virtual line connecting the tip of the first contact rib 156a and the tip of the second contact rib 156b is formed to be substantially parallel to the inclined guide portion 72.

[0099] By releasing the pressing force on the skin S side against the chemical solution administration device 10, as shown in Fig. 30, the cover sleeve 14 is biased and moved toward the distal end side (in the direction of arrow B) with respect to the sleeve body 22 of the housing 12 by the elastic force of the sleeve spring 42, and the distal end of the sleeve body 22 moves to a position where it is more on the distal end side than the puncture needle 126, so that the puncture needle 126 is covered.

[0100] Also, as shown in Figs. 30 and 31, the lock pin 44 moves toward the distal end side (in the direction of arrow B) together with the cover sleeve 14, and its lock claw 62 is engaged with the lock groove 40 of the sleeve body 22, thereby restricting the axial movement of the lock pin 44 with respect to the sleeve body 22. Accordingly, the movement of the slide sleeve 64 that abuts against the distal end of the sleeve body 22 and the movement of the proximal end side (in the direction of arrow A) of the cover sleeve 14 that abuts against the distal end of the slide sleeve 64 are also restricted.

[0101] As a result, as shown in Figs. 30 and 31, in the chemical solution administration device 10 from which the chemical solution administration has ended and the patient has detached from the skin S, the puncture needle 126 is completely covered by the cover sleeve 14, and the movement of the cover sleeve 14 toward the proximal end side is restricted, so that the puncture needle 126 is not exposed to the outside by the cover sleeve 14 and is safe.

[0102] As described above, in the present embodiment, the plunger rod 82 is accommodated inside the housing 12 constituting the chemical solution administration device 10 so as to be movable in the axial direction (directions of arrows A and B), and on the inner peripheral surface of the sleeve body 22 facing the outer peripheral surface of the plunger rod 82, a plurality of guide ribs 34 protruding radially inward are provided. On the other hand, on the outer peripheral surface of the plunger rod 82, a plurality of slide grooves 92 that are recessed radially inward and into which the respective guide ribs 34 are inserted are formed along the axial direction. The guide ribs 34 and the slide grooves 92 are provided at least in three or more along the circumferential direction of the sleeve body 22 and the plunger rod 82 and are formed along the axial direction. Between the guide rib 34 and the slide groove 92, a first clearance Cr1 is provided in the extending direction of the guide rib 34, and a second clearance Cr2 is provided in a direction orthogonal to the extending direction.

[0103] As a result, compared with the conventional chemical solution administration device that ensured straightness with respect to the casing by managing the diameter dimension of the piston, by making the width dimensions of the respective guide ribs 34 and the slide grooves 92 smaller than the diameter dimension of the piston, dimensional tolerance can be suppressed to a small value. Therefore, radial position variation (eccentricity) of the plunger rod 82 with respect to the sleeve body 22 can be preferably suppressed and straightness can be enhanced.

[0104] Therefore, when the plunger rod 82 is biased and moved toward the tip side by the elastic force of the injection spring 58 inside the housing 12, the plunger rod 82 is guided along each guide rib 34 inserted into each slide groove 92, so that the plunger rod 82 does not rotate relative to the housing 12, and moreover, it can be moved linearly toward the tip side (direction of arrow B).

[0105] As a result, in the chemical solution administration device 10, by suppressing eccentricity of the plunger rod 82 with respect to the housing 12 and enhancing straightness, the plunger rod 82 can be smoothly moved toward the tip side, and administration of the chemical solution and generation of the first and second confirmation sounds can be stably performed.

[0106] Furthermore, each guide rib 34 has a protrusion 36 that projects in the width direction orthogonal to the extending direction at an end portion inserted into the slide groove 92 and extending along the extending direction. Therefore, when the plunger rod 82 moves axially along the guide rib 34, only the protrusion 36 contacts the slide groove 92. For example, compared with the case where the widthwise end portion of the guide rib 34 is in surface contact with the entire surface of the slide groove 92, the contact resistance can be reduced. As a result, the sliding resistance when the plunger rod 82 moves axially along the housing 12 is suppressed, and the plunger rod 82 can be moved more smoothly toward the tip side.

[0107] Furthermore, by arranging a plurality of guide ribs 34 at equal intervals along the circumferential direction of the plunger rod 82, it is possible to more suitably suppress the eccentricity of the plunger rod 82 with respect to the housing 12 and make it closer to the coaxial state.

[0108] Still further, in the chemical solution administration device 10 described above, a configuration in which four slide grooves 92 are provided on the outer peripheral surface of the plunger rod 82 (rod body 84) and four guide ribs 34 that project radially inward and are inserted into the slide grooves 92 are provided on the inner peripheral surface of the sleeve body 22 (body main body 30) facing the outer peripheral surface has been described. Conversely, guide ribs 34 that project radially outward may be formed on the outer peripheral surface of the plunger rod 82, and slide grooves 92 into which the guide ribs 34 are inserted may be formed on the inner peripheral surface of the sleeve body 22.

[0109] Note that the chemical solution administration device according to the present invention is not limited to the above-described embodiments, and various configurations can be adopted without departing from the gist of the present invention, of course.

Claims

1. A chemical solution administration device (10) for administering a chemical solution (M) into a living body, comprising: a housing (12) formed in a hollow cylindrical shape; a syringe (16) accommodated in the housing and having a cylinder (20) filled with the chemical solution and a puncture needle (126) communicating with the cylinder and administering the chemical solution into the living body; a hollow cylindrical needle cover (14) provided inside the housing, covering the tip side of the syringe, and relatively displaced in the proximal direction with respect to the housing by being pressed against a puncture target; a plunger (82) provided inside the housing, the tip of which moves inside the cylinder to discharge the chemical solution from the puncture needle; and a cap (18) detachably provided at the tip of the needle cover and removed when the puncture needle punctures the puncture target. Either the inner peripheral surface of the housing or the outer peripheral surface of the plunger facing the inner peripheral surface is provided with a plurality of guide ribs (34) protruding toward the other. The other of the inner peripheral surface of the housing and the outer peripheral surface of the plunger is provided with a guide groove (70) into which at least a part of the guide rib is inserted and which extends along the moving direction of the plunger. At least three or more guide ribs are provided and formed along the axial direction. Between the guide rib and the guide groove, there are a first clearance (Cr1) provided in the extending direction of the guide rib and a second clearance (Cr2) provided in a direction orthogonal to the extending direction. The guide rib further has a protrusion (36) protruding in a direction substantially orthogonal to the extending direction at an end portion inserted into the guide groove and extending along the extending direction. The chemical solution administration device.

2. In the chemical solution administration device according to Claim 1, The protrusion is formed to gradually taper in a direction away from the guide rib. The chemical solution administration device.

3. In the chemical solution administration device according to Claim 1 or 2, The guide ribs are arranged at equal intervals along the circumferential direction of the plunger. The chemical solution administration device.

Images