Liquid medicine administration device, drive unit, and cartridge

Abstract

A liquid medicine administration device (10) comprises a cartridge (16) and a drive unit (18). The cartridge (16) includes a reservoir (22) capable of accommodating a liquid medicine (M), and a plunger (24) provided in such a manner as to be capable of moving in the axial direction of the reservoir (22) in order to discharge the liquid medicine (M) from the reservoir (22). The drive unit (18) includes a drive mechanism (40) for driving the plunger (24) in the axial direction, and has the cartridge (16) detachably provided thereto. The plunger (24) is accommodated in the reservoir (22). The drive mechanism (40) biases the plunger (24) toward the leading end direction.

Description

Drug solution administration device, drive unit, and cartridge

[0001] The present disclosure relates to a drug solution administration device, a drive unit, and a cartridge.

[0002] Japanese Patent No. 5506780 discloses a drug solution administration device including a reservoir for filling a drug solution. The drug solution administration device includes a reusable part and a disposable part. The drug solution administration device is used with the reusable part and the disposable part assembled to each other. The disposable part includes a piston inserted into a drug chamber filled with a drug solution and a piston rod extending axially from the piston. The reusable part includes a drive mechanism. In a state where the reusable part and the disposable part are assembled, the drive mechanism and the piston rod are connected. By driving the drive mechanism, the piston moves in the drug chamber and the drug solution is administered to the living body.

[0003] Japanese Patent No. 5506780

[0004] In a drug solution administration device such as Japanese Patent No. 5506780, the piston rod is disposed to protrude outside the drug chamber. Therefore, when assembling the reusable part and the disposable part, there is a problem that an operator may accidentally touch the piston rod, and the piston rod and the piston may move from a predetermined position.

[0005] An object of the present disclosure is to solve the above-described problems.

[0006] (1) A first aspect of the present disclosure is a drug solution administration device including a cartridge having a reservoir capable of accommodating a drug solution and a plunger provided movably in the axial direction of the reservoir to discharge the drug solution from the reservoir, and a drive unit having a drive mechanism for driving the plunger in the axial direction, the cartridge being detachable. The plunger has a length that can be accommodated inside the reservoir, and the drive mechanism biases the plunger toward the tip direction.

[0007] According to this drug solution administration device, when assembling the cartridge and the drive unit, since the plunger does not protrude from the reservoir, contact between the plunger and the user is effectively prevented.

[0008] (2) In the drug solution dispensing device described in (1) above, the drive mechanism may include a plunger pressing part that moves in the axial direction, contacts the plunger, and pushes it toward the tip.

[0009] This configuration allows the plunger to be effectively moved by the plunger pressing section.

[0010] (3) In the drug administration device described in (2) above, the plunger and the plunger pressing portion may be spaced apart from each other in the axial direction in the initial state before the drive unit and the cartridge are assembled and the drive mechanism is driven.

[0011] This configuration effectively prevents the plunger pressing portion and the plunger from coming into contact with each other when assembling the drive unit and the cartridge.

[0012] (4) In the drug dispensing device described in (2) or (3) above, when the drive mechanism moves toward the plunger, the plunger pressing portion and the plunger are provided with a contact portion into which they come into contact with each other, and the contact portion may have a first contact portion provided on one of the plunger pressing portion and the plunger and protruding in the axial direction, and a second contact portion provided on the other of the plunger pressing portion and the plunger and recessed in the axial direction into which the first contact portion is inserted.

[0013] This configuration allows the engaging portion to effectively transmit the axial force generated by the movement of the drive mechanism to the plunger. The insertion of the first contact portion into the second contact portion effectively prevents relative movement between the plunger pressing portion and the plunger in a direction intersecting the axial direction.

[0014] (5) In the drug solution dispensing device described in any one of (2) to (4) above, the reservoir comprises a cylindrical reservoir body having a drug chamber inside into which the drug solution is introduced, a reservoir opening opening at the base end of the reservoir body, and a guide portion provided in the reservoir opening, wherein the guide portion may have a guide hole that penetrates the plunger in the axial direction and into which at least one of the plunger and the plunger pressing portion is inserted.

[0015] This configuration allows the guide hole to effectively support at least one of the plunger and the plunger pressing portion along the axial direction, thereby improving the straightness of the plunger's movement.

[0016] (6) In the drug solution dispensing device described in (5) above, the plunger comprises a plunger body that is liquid-tightly inserted into the drug chamber and a plunger rod that extends axially from the plunger body, wherein the plunger rod is inserted into the guide hole, and when the plunger is pushed toward the tip by the plunger pressing portion and the plunger body moves to the tip of the drug chamber, the base end of the plunger rod and the tip of the plunger pressing portion may be inserted into the guide hole.

[0017] In this configuration, the plunger rod is effectively supported by the guide section as the plunger moves, and furthermore, when the plunger pushes out all the liquid in the chamber, the plunger pressing section is effectively supported by the guide section along with the plunger.

[0018] (7) In the drug administration device described in any one of (1) to (6) above, the cartridge is mounted on the mounting portion of the drive unit, and the reservoir may be provided with a sealing member that contacts the mounting portion.

[0019] This configuration effectively maintains liquid-tightness between the cartridge and the drive unit through the sealing member.

[0020] (8) A second aspect of the present disclosure is a drive unit to which a cartridge having a reservoir capable of containing a drug solution and a plunger disposed in the reservoir can be attached and detached, comprising a drive mechanism for driving the plunger in the axial direction, the drive mechanism having a plunger pressing portion that moves in the axial direction to bias the plunger toward the tip.

[0021] This drive unit effectively suppresses contact between the drive mechanism and the plunger when assembling the cartridge and the drive unit.

[0022] (9) A third aspect of the present disclosure is a cartridge that is detachable from a drive unit, which includes a reservoir capable of containing a chemical solution and a plunger that is movable in the axial direction of the reservoir for discharging the chemical solution from the reservoir, and a drive mechanism for biasing the plunger toward the tip, wherein the plunger is of a length that can be accommodated inside the reservoir.

[0023] With this cartridge, the plunger does not protrude outside the reservoir, effectively preventing users from accidentally touching the plunger when handling the cartridge.

[0024] According to this disclosure, when assembling the cartridge and the drive unit, the plunger does not protrude from the reservoir, thus effectively preventing contact between the plunger and the user.

[0025] Figure 1 is an external perspective view of a drug dispensing device according to an embodiment of the present disclosure. Figure 2 is an exploded perspective view of the pump section of the drug dispensing device shown in Figure 1. Figure 3 is a perspective view of the pump section of the drug dispensing device viewed from below. Figure 4 is a partially cutaway plan view of the pump section of Figure 3. Figure 5 is a cross-sectional view along the line V-V in Figure 4. Figure 6 is a cross-sectional view along the line VI-VI in Figure 5. Figure 7 is a first explanatory diagram showing the drug dispensing device in use. Figure 8 is a perspective view of the drive mechanism including the plunger pressing section. Figure 9 is an enlarged perspective view showing the tip of the drive unit. Figure 10 is a cross-sectional view along the line X-X in Figure 9. Figure 11 is a first explanatory diagram showing the operation of the detachment prevention mechanism shown in Figure 10. Figure 12 is a second explanatory diagram showing the drug dispensing device in use. Figure 13 is a cross-sectional explanatory diagram showing the drug dispensing device attached to a living body. Figure 14 is a second explanatory diagram showing the operation of the detachment prevention mechanism. Figure 15 is a third explanatory diagram showing the drug dispensing device in use. Figure 16 is the fourth explanatory diagram showing the usage status of the drug administration device.

[0026] The drug delivery device 10 according to this embodiment is used to deliver a drug solution M to a living body B (e.g., a patient) by being attached to the surface of a target area (e.g., skin S) of the living body B (see Figure 13). Specifically, the drug delivery device 10 is fixed to the skin S of the living body B by an adhesive sheet 141 provided on the lower surface of the holder 14, for example. Hereinafter, "downward" or "lower surface" refers to the direction or surface facing the living body B when the drug delivery device 10 is fixed to the living body B. "Upward" or "upper surface" refers to the direction or surface facing away from the living body B when the drug delivery device 10 is fixed to the living body B.

[0027] As shown in Figure 1, the drug dispensing device 10 comprises a pump unit 12 and a holder 14. The pump unit 12 is detachably attached to the holder 14.

[0028] As shown in Figure 2, the pump unit 12 comprises a cartridge 16 and a drive unit 18. The pump unit 12 is used with the cartridge 16 and the drive unit 18 assembled together. The drive unit 18 is a reusable part, and the cartridge 16 is a disposable part.

[0029] The drug dispensing device 10 is operated by a handset (not shown). The handset communicates with the communication unit of the drive unit 18. The handset may be a dedicated terminal or a smartphone or other device with a dedicated application downloaded.

[0030] As shown in Figure 3, the cartridge 16 is detachably mounted on the mounting portion 20 of the drive unit 18. As shown in Figure 4, the cartridge 16 comprises a reservoir 22, a plunger 24, and a flow path forming member 26. The cartridge 16 is provided in a sterilized state, contained in blister packaging or the like.

[0031] The reservoir 22 is capable of containing the chemical solution M (see Figure 7). As shown in Figure 5, the reservoir 22 comprises a reservoir body 221, a reservoir opening 222, and a guide portion 223.

[0032] The reservoir body 221 is formed in the shape of a syringe barrel and has a chamber 28 inside into which the drug solution M is introduced (see Figure 7). When viewed from the axial direction of the reservoir 22, the cross-section of the reservoir body 221 is approximately circular (see Figure 11). However, the cross-section of the reservoir body 221 is not limited to being formed in a circular shape.

[0033] As shown in Figure 4, the tip of the reservoir body 221 is equipped with a drug solution flow section 30. The drug solution flow section 30 communicates with the drug chamber 28 (see Figure 5). The drug solution flow section 30 extends in a direction intersecting the axis of the reservoir body 221. The drug solution flow section 30 can introduce the drug solution M into the reservoir 22 from outside the reservoir 22. The drug solution flow section 30 can guide the drug solution M from inside the reservoir 22 to the outside of the reservoir 22.

[0034] As shown in Figure 5, the reservoir opening 222 is provided at the base end of the reservoir body 221. The reservoir opening 222 opens towards the base end at the base end of the reservoir body 221.

[0035] The guide portion 223 is formed in a disc shape and is provided at the base end of the reservoir body 221. The guide portion 223 covers the reservoir opening 222. As shown in Figure 6, the guide portion 223 is provided with a guide hole 32. The guide hole 32 penetrates the guide portion 223 in the axial direction of the plunger 24. The plunger 24 and a part of the drive mechanism 40 are movably inserted into the guide hole 32. In this embodiment, a pair of guide holes 32 are provided, and the pair of guide holes 32 are spaced apart from each other in a direction intersecting the axial direction of the reservoir 22, but are not limited to this. For example, there may be one guide hole 32 or three or more.

[0036] The base end of the guide portion 223 is equipped with an annular sealing member 34. The sealing member 34 is fitted into a groove formed on the outer circumference of the base end of the guide portion 223. The sealing member 34 protrudes radially outward from the outer circumference of the base end. When the cartridge 16 is housed in the mounting portion 20 of the drive unit 18, the sealing member 34 comes into contact with the inner surface of the fitting portion 203 of the mounting portion 20, which will be described later.

[0037] As shown in Figure 6, in the initial state (ready to use), the entire plunger 24 is housed inside the reservoir 22. The plunger 24 is provided to be movable in the axial direction of the reservoir 22. The plunger 24 comprises a plunger body 241 and a pair of plunger rods 242. The plunger body 241 is liquid-tightly inserted into the reservoir body 221 of the reservoir 22. The cross-section of the plunger body 241 is circular, corresponding to the cross-section of the reservoir body 221, and a plunger seal member 243 is attached to the outer circumference of the tip. As a result, a sealed chamber 28 is formed between the reservoir body 221 and the tip of the plunger body 241 (see Figure 7). The chamber 28 can be filled with a chemical solution M.

[0038] The plunger rods 242 extend from the plunger body 241 toward the base end. The pair of plunger rods 242 are arranged parallel to each other and spaced apart in the radial direction of the plunger body 241. Each of the pair of plunger rods 242 can be inserted into the guide hole 32 of the guide portion 223.

[0039] When the reservoir 22 (medication chamber 28) is not filled with the chemical solution M, the plunger 24 is housed inside the reservoir 22. When the plunger 24 is pushed all the way to the tip, it is of a length that does not protrude from the reservoir 22. That is, the plunger rod 242 does not protrude from the base end of the guide hole 32 toward the base end. As shown in Figure 7, when the chemical solution M is filled into the chamber 28 of the reservoir 22, the chemical solution M pushes the plunger 24 toward the base end and moves it. At this time, the plunger rod 242 moves toward the base end beyond the base end of the reservoir 22 through the guide hole 32. After the chemical solution M is filled into the chamber 28 of the reservoir 22, the plunger 24 moves toward the tip of the reservoir 22 by the drive mechanism 40, thereby discharging the chemical solution M from the reservoir 22.

[0040] As shown in Figure 4, the flow path forming member 26 is positioned on the outer circumference of the reservoir body 221. The flow path forming member 26 is positioned parallel to the reservoir 22 and fixed to the reservoir body 221. The flow path forming member 26 extends along the axial direction of the reservoir 22. The flow path forming member 26 has a flow passage 261 through which the drug solution M can flow. The flow passage 261 is formed along the extending direction of the flow path forming member 26. The tip of the flow path forming member 26 faces the drug solution flow section 30. The tip of the flow passage 261 is connected to the drug solution flow section 30, allowing them to communicate with each other. The base end of the flow path forming member 26 is positioned in the cannula unit housing section 50 of the internal housing 38. The base end of the flow passage 261 can be connected to the cannula unit 94, which will be described later (see Figure 13).

[0041] As shown in Figure 3, the cartridge 16 further includes an extraction assist structure 36. The extraction assist structure 36 is provided to move the cartridge 16 away from the mounting portion 20 when the cartridge 16 mounted on the mounting portion 20 of the drive unit 18 is extracted. The extraction assist structure 36 includes a protruding portion 361. The protruding portion 361 is provided on the outer circumference of the reservoir 22. As shown in Figure 5, the protruding portion 361 is provided on the guide portion 223. The protruding portion 361 is a convex portion that protrudes radially outward from the outer circumference of the guide portion 223 of the reservoir 22. The protruding portion 361 protrudes outward from the outer wall portion 382 of the internal housing 38 in the drive unit 18, which will be described later. Note that the protruding portion 361 is not limited to protruding outward from the outer wall portion 382 of the internal housing 38. For example, the protruding portion 361 may be flush with the outer wall portion 382, ​​or positioned inside the internal housing 38 beyond the outer wall portion 382. The protruding portion 361 only needs to be exposed to the outside through the opening 381. Since the cartridge 16 has a small capacity of about 2 to 3 mL, the removal assist structure 36 makes it easy to attach and detach.

[0042] As shown in Figure 3, the removal assist structure 36 may further include a tab member 362. The tab member 362 is formed in a sheet shape and extends along the axial direction of the reservoir 22. The tip of the tab member 362 is fixed to the tip of the reservoir 22. The tab member 362 extends toward the base end of the reservoir 22. The base end of the tab member 362 is positioned on the outer circumference of the reservoir body 221. At least the base end of the tab member 362 is exposed to the outside through the opening 381 of the internal housing 38. The base end of the tab member 362 is a free end that is not fixed to the reservoir 22 and is provided so that it can be grasped by the user. By providing the tab member 362, it is possible to make it easier to remove the cartridge 16 (reservoir 22) from the drive unit 18 even if the plunger 24 protrudes toward the base end of the reservoir 22.

[0043] Note that the cartridge 16 is not limited to having an extraction assist structure 36. For example, the cartridge 16 mounted on the mounting section 20 may be removed to the outside by the user directly grasping it.

[0044] As shown in FIG. 4, the drive unit 18 includes an internal housing 38, a drive mechanism 40, a power supply unit 42, and an external housing 44.

[0045] The internal housing 38 includes a mounting portion 20 and an opening 381. The cartridge 16 is detachably mounted on the mounting portion 20. The mounting portion 20 is formed to be recessed in the thickness direction from the outer wall portion 382 of the internal housing 38 (see FIG. 5). The outer wall portion 382 of the internal housing 38 is a surface facing the holder 14 attached to the skin S of the living body B when the chemical solution M is administered to the living body B using the chemical solution administration device 10 (see FIG. 13). The mounting portion 20 is a housing portion 383 capable of housing the cartridge 16 therein. Note that the mounting portion 20 is not limited to the housing portion 383 recessed more than the outer wall portion 382 of the internal housing 38. For example, a configuration in which the mounting portion 20 is provided on the outer wall portion 382 of the internal housing 38 may also be used.

[0046] As shown in FIG. 4, the mounting portion 20 includes a reservoir mounting portion 201 and a flow path member mounting portion 202. The reservoir mounting portion 201 is disposed at a position close to the tip of the internal housing 38. The reservoir mounting portion 201 includes a housing bottom portion 461 (see FIG. 5) and a pair of housing side portions 462 (see FIG. 6). The housing bottom portion 461 is formed in an arc-shaped cross section and is disposed in a direction away from the outer wall portion 382 (see FIG. 10). Each of the pair of housing side portions 462 extends from the housing bottom portion 461 toward the outer wall portion 382 (see FIG. 10). When the cartridge 16 is mounted on the mounting portion 20, the reservoir 22 is housed in the reservoir mounting portion 201. The base end portion of the reservoir mounting portion 201 includes a fitting portion 203 into which the guide portion 223 is fitted (see FIG. 5). The flow path member mounting portion 202 is provided on the side of the reservoir mounting portion 201. When the cartridge 16 is mounted on the mounting portion 20, the flow path forming member 26 is housed in the flow path member mounting portion 202.

[0047] As shown in FIG. 3, the internal housing 38 has an opening 381. The opening 381 opens to the outer wall portion 382 and communicates with the mounting portion 20. As shown in FIG. 4, the opening 381 includes a first opening 481 that opens to the outer wall portion 382 and a second opening 482 that opens at the tip of the internal housing 38. The first opening 481 and the second opening 482 are connected. Through the opening 381, the cartridge 16 can be attached to and detached from the mounting portion 20. When the cartridge 16 is attached to the mounting portion 20, a part of the cartridge 16 is exposed to the outside through the opening 381 (see FIG. 3).

[0048] As shown in FIG. 3, the internal housing 38 further includes a cannula unit housing portion 50, a supported portion 52, and a holder detection portion SB. The cannula unit housing portion 50 is formed by being recessed from the outer wall portion 382 of the internal housing 38. The cannula unit housing portion 50 is disposed near the base end portion of the outer wall portion 382 of the internal housing 38. When the chemical solution administration device 10 is attached to the holder 14, the cannula unit 94 provided on the holder 14 is housed in the cannula unit housing portion 50 (see FIG. 13). The supported portion 52 is provided at the tip of the internal housing 38 and supports a detachment prevention mechanism 66 described later. The holder detection portion SB is provided on the outer wall portion 382 of the internal housing 38. After the attachment of the pump unit 12 to the holder 14 is completed, by detecting the presence of a protrusion (not shown) provided on the holder 14, the chemical solution administration device 10 becomes in a state where it can start administering the chemical solution M.

[0049] As shown in FIG. 4, the drive mechanism 40 is provided inside the internal housing 38. The drive mechanism 40 drives the plunger 24 in the axial direction in a state where the cartridge 16 is attached to the drive unit 18. The drive mechanism 40 includes a drive portion 401, a shaft 402, and a plunger pressing portion 403.

[0050] The drive unit 401 includes a motor 54 having a drive shaft 541. However, the drive unit 401 is not limited to the motor 54; it can be any rotational drive source. The shaft 402 has threads formed on its outer surface. The shaft 402 is rotatably supported in the internal housing 38. The shaft 402 is positioned facing the plunger 24. The shaft 402 is connected to the drive shaft 541 of the motor 54 via a gear mechanism 56. When the motor 54 is driven, the shaft 402 is rotationally driven via the drive shaft 541 and the gear mechanism 56. That is, the driving force of the drive unit 401 is transmitted to the shaft 402 via the gear mechanism 56.

[0051] The plunger pressing portion 403 moves toward the tip when driven by the drive unit 401, contacts the plunger 24, and pushes the plunger 24 toward the tip. With the cartridge 16 mounted on the drive unit 18, the plunger pressing portion 403 is positioned toward the base end of the plunger 24.

[0052] As shown in Figure 8, the plunger pressing portion 403 comprises a base end member 581, a tip end member 582, and an intermediate member 583. As shown in Figure 6, the base end member 581 is positioned at the base end of the plunger pressing portion 403. The base end member 581 is formed from, for example, a resin material. The base end member 581 has a shaft hole 60 into which the shaft 402 is screwed.

[0053] The tip-side member 582 is positioned towards the tip of the base-side member 581. The tip-side member 582 is formed from, for example, a resin material. The tip-side member 582 includes a pair of connecting arms 62. Each of the pair of connecting arms 62 protrudes toward the base end and is arranged parallel to each other. The end of each connecting arm 62 is provided with a claw portion 621. The pair of connecting arms 62 are inserted into a pair of connecting holes 64 of the base-side member 581. With the pair of connecting arms 62 inserted into the connecting holes 64, each claw portion 621 engages with the end face of the base-side member 581. This connects the base-side member 581 and the tip-side member 582 to each other in the axial direction of the shaft 402.

[0054] The intermediate member 583 is positioned between the base end member 581 and the tip end member 582. The intermediate member 583 is formed in the shape of a plate from, for example, a metal material. The intermediate member 583 is sandwiched between the base end member 581 and the tip end member 582 by connecting them to each other (see Figure 5).

[0055] As shown in Figure 6, in the initial state before the drive mechanism 40 is driven, when the drive unit 18 and cartridge 16 are assembled, the plunger pressing portion 403 of the drive mechanism 40 and the plunger 24 (plunger rod 242) are spaced apart from each other in the axial direction.

[0056] As the motor 54 drives, the shaft 402 rotates, causing the plunger pressing portion 403, including the base end member 581, to move toward the tip (towards the plunger 24). The plunger pressing portion 403 (tip end member 582) pushes the base end of the plunger rod 242 toward the tip (see Figure 12).

[0057] Furthermore, the plunger pressing portion 403 is not limited to being composed of three parts: a base member 581, a tip member 582, and an intermediate member 583. For example, the plunger pressing portion 403 may be configured such that the base member 581 and the tip member 582 are integrally formed, and a metal member corresponding to the intermediate member 583 is built inside. In this case, the plunger pressing portion 403 is preferably formed by insert molding. Also, the plunger pressing portion 403 is not limited to a configuration including a metal member; for example, the plunger pressing portion 403 may be formed solely from a resin material.

[0058] As shown in Figure 4, the power supply unit 42 is mounted on the circuit board K housed in the internal housing 38. The power supply unit 42 supplies power to the drive unit 401 of the drive mechanism 40 via the circuit board K. The power supply unit 42 includes a battery.

[0059] As shown in Figure 13, the outer housing 44 is provided so as to cover the upper part of the inner housing 38. The outer housing 44 is fixed to the inner housing 38 while covering the upper part of the inner housing 38. The inner housing 38 and the outer housing 44 are fixed together via a housing seal 45 (see Figure 10). As a result, the drive mechanism 40 and the power supply unit 42 are housed in the space between the inner housing 38 and the outer housing 44 (see Figures 4 and 5).

[0060] As shown in Figure 3, the drive unit 18 is further equipped with a detachment prevention mechanism 66.

[0061] The detachment prevention mechanism 66 is provided to the outer wall portion 382 of the inner housing 38 so as to be openable and closable. As shown in Figure 4, the detachment prevention mechanism 66 is provided at the tip of the inner housing 38. The detachment prevention mechanism 66 is provided so as to be switchable between an open position and a closed position by opening and closing it. In the closed position of the detachment prevention mechanism 66, the detachment prevention mechanism 66 prevents the cartridge 16 mounted on the mounting portion 20 from detaching from the inner housing 38. In the closed position, the detachment prevention mechanism 66 closes a part of the opening 381 of the inner housing 38. On the other hand, in the open position of the detachment prevention mechanism 66, the detachment prevention mechanism 66 allows the cartridge 16 to detach from the mounting portion 20 (see Figure 11).

[0062] As shown in Figure 9, the release prevention mechanism 66 comprises a stopping member 68, a biasing member 70, and a locking mechanism 72 (see Figure 10). The stopping member 68 extends in the width direction of the internal housing 38. As shown in Figure 4, the width direction of the internal housing 38 intersects with the axial direction of the plunger 24 and the thickness direction of the internal housing 38.

[0063] The blocking member 68 is rotatably supported by the internal housing 38. The blocking member 68 comprises a support end 681 and a free end 682. The support end 681 is provided at one end in the extending direction of the blocking member 68. The support end 681 has a support portion 683. As shown in Figure 4, the support portion 683 is rotatably supported by a support pin 74 perpendicular to the extending direction of the blocking member 68 on the supported portion 52 of the internal housing 38. At the tip of the internal housing 38, the support end 681 is supported at the center of the internal housing 38 in the width direction. The free end 682 is provided at the end of the blocking member 68 opposite to the support end 681 in the extending direction. The free end 682 is positioned at the widthwise end of the internal housing 38. The blocking member 68 has a cantilever structure in which the free end 682 side is rotatable with the support portion 683 as the pivot point (see Figure 16). In the closed position of the blocking member 68, the blocking member 68 is positioned so as to intersect with the opening direction of the opening 381 of the internal housing 38. Note that the blocking member 68 is not limited to being rotatably supported by the internal housing 38. For example, the blocking member 68 may be slidably supported in the width direction of the internal housing 38, and the opening 381 may be opened and closed by sliding the blocking member 68.

[0064] As shown in Figure 9, the blocking member 68 further comprises a main body portion 761, a side wall portion 762, and a holding portion 763 (see Figure 7). The main body portion 761 is formed in a flat plate shape from the support end 681 to the free end 682. The side wall portion 762 is provided at the tip of the blocking member 68. The side wall portion 762 is formed in a wall shape that protrudes in the thickness direction from the tip of the main body portion 761. The holding portion 763 is provided inside the main body portion 761 and the side wall portion 762. The holding portion 763 protrudes from the inner surface of the side wall portion 762 toward the base end. As shown in Figure 5, the holding portion 763 faces the reservoir 22 in the axial direction when the blocking member 68 is in the closed position. When the blocking member 68 is in the closed position, the tip of the reservoir 22 (chemical liquid flow portion 30) can come into contact with the holding portion 763. The holding portion 763 prevents the reservoir 22 from moving toward the tip. When the blocking member 68 is in the closed position, the annular sealing member 34 located on the base end side of the reservoir 22 is in close contact with the inner surface of the fitting portion 203. As a result, the inside of the drive unit 18 is sealed, and the electronic equipment inside the drive unit 18 is protected from the ingress of liquids, etc.

[0065] The retaining portion 763 may be configured to always contact the tip of the reservoir 22 when the blocking member 68 is in the closed position, or it may be configured to contact the tip of the reservoir 22 when the reservoir 22 moves toward the tip. The retaining portion 763 is not limited to a configuration that allows contact with the tip of the reservoir 22 (chemical liquid flow portion 30). For example, a protrusion may be provided on the outer circumference of the reservoir body 221, and the retaining portion 763 may be positioned toward the tip of the protrusion to allow contact.

[0066] As shown in Figure 5, in the closed position of the blocking member 68, the main body portion 761 of the blocking member 68 is positioned to cover a part of the first opening 481, and the side wall portion 762 is positioned to cover the second opening 482.

[0067] As shown in Figure 10, the biasing member 70 causes the blocking member 68 to open in a direction away from the mounting portion 20. The biasing member 70 is, for example, a torsion spring. A support pin 74 is inserted into the biasing member 70. The biasing member 70 is positioned between the internal housing 38 and the support end 681 of the blocking member 68. The biasing force of the biasing member 70 biases the blocking member 68 in a direction that causes the free end 682 of the blocking member 68 to open away from the first opening 481. That is, the biasing force of the biasing member 70 causes the blocking member 68 to open and reach the open position (see Figure 11). Note that the release prevention mechanism 66 is not limited to a configuration that includes a biasing member 70. For example, instead of the biasing force of the biasing member 70, the user may grip the blocking member 68 to cause it to open.

[0068] The locking mechanism 72 prevents the release prevention mechanism 66 from opening due to the biasing member 70 when the release prevention mechanism 66 is in the closed position. The locking mechanism 72 also prevents the release prevention mechanism 66 from moving relative to the internal housing 38 when the release prevention mechanism 66 is in the closed position. The locking mechanism 72 comprises a locking pin 721, a locking hole 722, a locking biasing member 723, and a release mechanism 724.

[0069] The lock pin 721 is movably mounted on the blocking member 68. The lock pin 721 is mounted so as to protrude outward from the free end 682 of the blocking member 68. The lock pin 721 is positioned along the width direction of the internal housing 38 (see Figure 4). The extending direction of the lock pin 721 is the same as the extending direction of the blocking member 68. The lock pin 721 is positioned inside the mounting portion 20 so as to be inside the blocking member 68 (on the cartridge 16 side). The lock pin 721 comprises a support end 781, an insertion end 782, and a pin intermediate portion 783. The support end 781 is positioned on the support portion 683 side of the blocking member 68. The insertion end 782 is positioned on the opposite side from the support end 781 in the extending direction of the lock pin 721. The insertion end 782 is inserted into the lock hole 722 of the internal housing 38 in the closed position. The insertion end 782 has an inclined portion. With the insertion end 782 inserted into the lock hole 722, the inclined portion is inclined upward from the lower surface of the insertion end 782 toward the outside of the lock hole 722.

[0070] The locking hole 722 is provided in the side wall of the internal housing 38. The locking pin 721 is inserted into the locking hole 722 when it is in the closed position. When it is in the closed position, the locking pin 721 and the locking hole 722 are arranged in a straight line in the width direction. The locking hole 722 of the internal housing 38 is covered. That is, the locking hole 722 is not exposed to the outside of the drug dispensing device 10.

[0071] The intermediate pin portion 783 is positioned between the support end 781 and the insertion end 782. The intermediate pin portion 783 has a link hole 80. The link hole 80 penetrates in a direction intersecting the extending direction of the lock pin 721. The link hole 80 extends in a vertical direction intersecting the extending direction of the lock pin 721 and is formed to be inclined upward toward the support end 781.

[0072] The locking biasing member 723 biases the lock pin 721 toward the lock hole 722. The locking biasing member 723 is, for example, a coil spring. The locking biasing member 723 is positioned between the blocking member 68 and the support end 781 of the lock pin 721. The locking biasing member 723 biases the lock pin 721 toward the widthwise outward direction of the internal housing 38 (towards the lock hole 722).

[0073] The release mechanism 724 can release the locked state of the detachment prevention mechanism 66 relative to the internal housing 38. The release mechanism 724 comprises a release operating member 821 and a link mechanism 822.

[0074] The release operation member 821 can be operated by the user when releasing the locked state of the release prevention mechanism 66. The release operation member 821 is provided so as to be movable relative to the prevention member 68. A part of the release operation member 821 is provided so as to be exposed on the outer surface of the main body 761.

[0075] In the locked state of the release prevention mechanism 66 by the locking mechanism 72, the release operation member 821 is in the locked position located on the free end 682 side along the extending direction of the prevention member 68.

[0076] The release operation member 821 comprises a rotatable support portion 841 and a release operation portion 842. The rotatable support portion 841 has a rotating shaft 86 that extends in a direction intersecting the extending direction of the blocking member 68. The rotatable support portion 841 is rotatably supported on the side wall portion 762 (see Figure 9) of the blocking member 68 via the rotating shaft 86. The rotatable support portion 841 rotatably supports the release operation member 821 about the rotating shaft 86. Note that the release operation member 821 is not limited to a configuration that allows rotation via the rotating shaft 86. For example, the release operation member 821 may be configured to slide along the extending direction of the blocking member 68.

[0077] The release operation unit 842 is exposed to the outside of the main body 761 of the blocking member 68 and is provided so that it can be released by the user. The release operation unit 842 is located on the opposite side of the rotation support unit 841 in a direction that intersects with the axis of the rotation shaft 86 of the rotation support unit 841 and also intersects with the direction of movement of the lock pin 721. The release operation unit 842 may be provided with a mark indicating the direction of operation.

[0078] The link mechanism 822 connects the release operating member 821 and the lock pin 721, and interlocks the lock pin 721 with the operation of the release operating member 821. The first end 881 of the link mechanism 822 is supported by the rotation support portion 841. The second end 882 is supported by the pin intermediate portion 783 via the link pin 883. The link pin 883 is inserted into the link hole 80 of the second end 882 and the pin intermediate portion 783. Note that the release operating member 821 is not limited to a configuration that allows rotation via the rotation shaft 86 and the link mechanism 822. For example, the release operating member 821 may be configured to move linearly along the extending direction of the blocking member 68 when releasing the locked state by the lock mechanism 72.

[0079] As shown in Figure 6, the drug dispensing device 10 further includes a contact portion 90.

[0080] As shown in Figure 12, the contact portion 90 refers to the portion where the plunger pressing portion 403 and the plunger 24 come into contact with each other when the drive mechanism 40 moves toward the plunger 24. The contact portion 90 comprises a first contact portion 921 and a second contact portion 922. The first contact portion 921 and the second contact portion 922 come into contact with each other.

[0081] As shown in Figure 6, the first contact portions 921 are provided at the base ends of each of the pair of plunger rods 242. Each of the pair of first contact portions 921 protrudes toward the base end (axial direction). In a cross-section along the direction of separation of the pair of plunger rods 242, each first contact portion 921 is tapered toward the base end.

[0082] The second contact portion 922 is provided at the tip of the plunger pressing portion 403. The second contact portion 922 is recessed from the tip of the plunger pressing portion 403 toward the base end (axial direction). In a cross-section along the separation direction of the pair of plunger rods 242, each second contact portion 922 is formed in a tapered shape toward the base end. The first contact portion 921 is inserted into the second contact portion 922 and engages with it (see Figure 12). Note that this is not limited to the case where the first contact portion 921 is provided on the plunger rod 242 and the second contact portion 922 is provided on the plunger pressing portion 403. For example, the first contact portion 921 may be provided on the plunger pressing portion 403 and protrude toward the tip, and the second contact portion 922 may be provided on the plunger rod 242 and formed recessed toward the tip. When the drive mechanism 40 moves toward the plunger 24, the plunger pressing part 403 and the plunger 24 come into contact with each other. When the drive mechanism 40 is driven in the direction of discharging the drug solution M, the plunger pressing part 403 presses against the plunger 24, and the drug solution M is delivered from the reservoir 22. After the administration of the drug solution M is complete, the cartridge 16 can be removed from the drive unit 18 by pulling only the plunger pressing part 403 back to its initial position.

[0083] The drug dispensing device 10 is not limited to a configuration that includes a contact portion 90. For example, the tip of the plunger pressing portion 403 and the base end of the plunger rod 242 may be engaged (for example, by friction engagement).

[0084] As shown in Figure 13, the holder 14 is fixed to the skin S (target area) of the living body B. The holder 14 has an adhesive sheet 141 that is fixed to the skin S of the living body B. When using the drug administration device 10, the pump unit 12 is attached to the holder 14 fixed to the skin S.

[0085] The drug administration device 10 further includes a cannula unit 94.

[0086] The cannula unit 94 is housed in the cannula unit housing section 50 of the cartridge 16. The cannula unit 94 comprises a unit body section 941 and a cannula 942 supported by the unit body section 941. The unit body section 941 has a connecting section 96 to which the base end of the flow path forming member 26 is connected. The inside of the connecting section 96 is connected to the flow path 261 of the flow path forming member 26. The tip of the cannula 942 protrudes beyond the adhesive sheet 141 of the holder 14 and is inserted into the living body B together with a puncture needle (not shown). The base end of the cannula 942 communicates with the inside of the connecting section 96 inside the internal housing 38.

[0087] The drug administration device 10 is used as follows.

[0088] First, the cartridge 16 is mounted on the drive unit 18. The following describes the initial state before the cartridge 16 is used, where the detachment prevention mechanism 66 is in the closed position and the preventing member 68 is locked by the locking mechanism 72.

[0089] The user releases the lock state of the detachment prevention mechanism 66 using the release operation member 821 while the outer wall portion 382 of the internal housing 38 of the drive unit 18 is facing upward. Specifically, from the locked state shown in Figure 10, the user moves the release operation portion 842, which is in the locked position, toward the support end 681 side of the prevention member 68. As a result, as shown in Figure 14, the release operation member 821 rotates inward in the width direction (towards the support end 681 side) with the rotation support portion 841 as the pivot point. Along with the rotation of the release operation member 821, the lock pin 721 moves in a direction in which the insertion end portion 782 detaches from the lock hole 722. The lock is released when the insertion end portion 782 of the lock pin 721 detaches from the lock hole 722. At this time, the link mechanism 822 rotates the release operation portion 842 of the release operation member 821 toward the mounting portion 20.

[0090] When the insertion end 782 of the lock pin 721 disengages from the lock hole 722, the lock state of the retaining member 68 of the release retaining mechanism 66 is released. As shown in Figure 11, the retaining member 68 rotates with its support end 681 as a pivot point, due to the biasing force of the biasing member 70, so that the free end 682 of the retaining member 68 moves away from the mounting portion 20 of the internal housing 38. As a result, as shown in Figure 15, the retaining member 68 moves away from the opening 381 and the mounting portion 20, and the release retaining mechanism 66 opens relative to the internal housing 38. Therefore, the first opening 481 and the second opening 482 are opened, and the cartridge 16 can be installed.

[0091] At this time, by operating the release operation member 821 to release the locked state of the lock mechanism 72, the blocking member 68 opens due to the biasing force of the biasing member 70.

[0092] Next, the cartridge 16 is attached to the mounting portion 20 of the drive unit 18. Specifically, as shown in Figure 16, the cartridge 16 is inserted into the mounting portion 20 from above through the opening 381. The reservoir 22 is housed in the reservoir mounting portion 201, and the flow path forming member 26 is housed in the flow path member mounting portion 202. The base end of the flow path forming member 26 is positioned in the cannula unit housing portion 50. This houses the cartridge 16 in the mounting portion 20 of the drive unit 18. At this time, the protruding portion 361 of the reservoir 22 is positioned on the opening 381 side (above). The sealing member 34 of the reservoir 22 abuts against the inner surface of the fitting portion 203 of the mounting portion 20. A liquid-tight seal is maintained between the base end of the reservoir 22 and the inner housing 38.

[0093] As shown in Figure 3, with the cartridge 16 housed in the mounting portion 20 of the drive unit 18, the detachment prevention mechanism 66 closes a portion of the opening 381. Specifically, the user grasps the free end 682 of the preventing member 68 of the detachment prevention mechanism 66, which is in the open position, and rotates it so that the free end 682 faces the internal housing 38, using the support portion 683 as a pivot point. The preventing member 68 is then rotated to the closed position until its main body portion 761 is aligned with the outer wall portion 382 of the internal housing 38. In the closed position, a portion of the opening 381 of the internal housing 38 is covered by the preventing member 68. More specifically, a portion of the first opening 481 is covered by the main body portion 761 of the preventing member 68, and the second opening 482 is covered by the side wall portion 762 (see Figure 9).

[0094] As the release prevention mechanism 66 rotates toward the closed position, the insertion end 782 of the lock pin 721 contacts the side wall 762 of the internal housing 38. This contact with the side wall 762 compresses the lock biasing member 723, causing the lock pin 721 to move over the side wall 762. After the insertion end 782 moves over the side wall 762, in the closed position the insertion end 782 faces the lock hole 722, causing the lock biasing member 723 to move the lock pin 721 toward the lock hole 722. The biasing force of the lock biasing member 723 causes the insertion end 782 of the lock pin 721 to be inserted into the lock hole 722. As a result, in the closed position of the release prevention mechanism 66, the opening operation of the release prevention mechanism 66 is prevented, resulting in a locked state (see Figure 10). The release prevention mechanism 66 prevents the cartridge 16 mounted on the mounting portion 20 from detaching from the internal housing 38. The retaining portion 763 of the detachment prevention mechanism 66 is positioned to face the liquid flow portion 30 of the reservoir 22 (see Figure 12).

[0095] This completes the mounting of the cartridge 16 to the mounting portion 20 of the drive unit 18. When the drive unit 18 and the cartridge 16 are assembled together, the power supply unit D provided on the circuit board K is turned on. When the power supply unit D is turned on, power can be supplied from the power supply unit 42 to the drive unit 401. As shown in Figure 4, in the initial state after the drive unit 18 and the cartridge 16 are assembled together and before the drive mechanism 40 is driven, the plunger 24 of the cartridge 16 and the plunger pressing portion 403 of the drive unit 18 are spaced apart in the axial direction.

[0096] Next, the reservoir 22 is filled with the drug solution M. Specifically, a drug delivery device (not shown), such as a syringe filled with the drug solution M, is prepared, and the drug solution M is filled into the drug chamber 28 of the reservoir 22 through a port (not shown) in the cannula unit housing section 50.

[0097] As shown in Figure 7, when the drug chamber 28 is filled with the drug solution M, the plunger 24 is pushed and moved toward the base end by the drug solution M. The plunger rod 242 protrudes toward the base end beyond the reservoir 22 through the guide hole 32 of the guide portion 223. Inside the internal housing 38, the plunger rod 242 moves toward the plunger pressing portion 403, and the first contact portion 921 of the plunger rod 242 is inserted into the second contact portion 922 of the plunger pressing portion 403. After the filling of the reservoir 22 with the drug solution M is complete, the drug solution delivery device (not shown) is removed from the cartridge 16.

[0098] Next, with the holder 14 pre-fixed to the skin S of a predetermined site on the living body B via the adhesive sheet 141, the puncture needle of a puncture device (not shown) and the cannula 942 are inserted into the skin S of the living body B. With the cannula 942 placed subcutaneously, the puncture device (not shown) is removed, leaving only the cannula 942 subcutaneously. The unit body 941 of the cannula unit 94 is fixed to the holder 14 by the puncture device (not shown) when the cannula 942 is placed.

[0099] Next, the pump unit 12 is attached to the holder 14. Specifically, as shown in Figure 13, the internal housing 38 of the drive unit 18 is brought into contact with the holder 14. The unit body 941 of the cannula unit 94 is housed in the cannula unit housing 50. When the user slides the pump unit 12 toward the base end with the lower surface of the pump unit 12 in contact with the upper surface of the holder 14, the base end of the flow path forming member 26 and the unit body 941 are connected, and the flow passage 261 and the cannula 942 communicate with each other.

[0100] At this point, the holder detection unit SB detects that the connection to the holder 14 is complete, and the device becomes ready for administration. In response to an instruction from a handset (not shown), the drive shaft 541 of the drive unit 401 rotates, causing the shaft 402 to rotate in a predetermined direction via the gear mechanism 56. As shown in Figure 12, as the shaft 402 rotates, the plunger pressing unit 403 moves toward the tip, pushing the plunger rod 242 toward the tip.

[0101] As the plunger 24 moves toward the tip, the plunger body 241 pushes the drug solution M out of the drug chamber 28 and flows from the drug solution distribution section 30 into the flow passage 261. As shown in Figure 13, the drug solution M in the flow passage 261 is administered subcutaneously to the living organism B through the cannula 942 via the unit body 941 of the cannula unit 94 from the base end of the flow path forming member 26. At this time, as shown in Figure 12, the plunger rod 242 is supported by the guide hole 32, and the plunger 24 moves toward the tip.

[0102] When the plunger body 241 reaches the tip of the drug chamber 28 due to the plunger pressing part 403, the drug solution M in the drug chamber 28 is administered to the patient, completing the administration. At this time, the plunger rod 242 of the plunger 24 is housed inside the reservoir body 221 through the guide hole 32 of the guide part 223, and the tip of the plunger pressing part 403 is inserted into the guide hole 32 (see the dashed line shape in Figure 12). In this way, the plunger pressing part 403 can compensate for the length of the plunger 24 on the cartridge 16 side. As a result, the axial length of the cartridge 16 and the drug solution administration device 10 can be shortened, and the drug solution administration device 10 can be made smaller.

[0103] The pump unit 12 is detachable from the holder 14. For example, when a patient takes a bath, the delivery (administration) of the drug solution M can be stopped using the handset, the pump unit 12 can be removed from the holder 14, and then reconnected after bathing to resume the administration of the drug solution M.

[0104] After the drug administration device 10 has finished administering the drug solution M to the living organism B, the pump unit 12 is removed from the holder 14. The cartridge 16 is removed from the drive unit 18 of the pump unit 12, and the used cartridge 16 is discarded. When removing the cartridge 16 from the drive unit 18, the user releases the lock state of the detachment prevention mechanism 66, rotates the stopping member 68 to open the opening 381, and then removes it. The operation of the detachment prevention mechanism 66 is the same as when the cartridge 16 is attached to the drive unit 18, so a detailed explanation is omitted. After the cartridge 16 is removed, the drive unit 18 is reusable.

[0105] As shown in Figure 16, the blocking member 68 of the detachment prevention mechanism 66 is rotated to open the opening 381, and the user pushes the protruding portion 361 of the reservoir 22 toward the tip of the internal housing 38. As a result, the cartridge 16 including the reservoir 22 moves toward the tip and is pushed out of the mounting portion 20 to the outside. Alternatively, the user may grasp the base end of the tab member 362 and pull it toward the direction away from the internal housing 38, thereby pulling the reservoir 22 out of the mounting portion 20 through the opening 381 to the outside.

[0106] This embodiment provides the following effects.

[0107] As shown in Figure 4, the drug dispensing device 10 comprises a cartridge 16 having a reservoir 22 and a plunger 24, and a drive unit 18 having a drive mechanism 40 to which the cartridge 16 can be attached and detached. The axial length of the plunger 24 is such that it can be housed inside the reservoir 22, and the drive mechanism 40 biases the plunger 24 toward the tip.

[0108] With this drug dispensing device 10, when assembling the cartridge 16 with the drive unit 18 or when removing the cartridge 16 from its packaging, the plunger 24 does not protrude from the reservoir 22, effectively preventing contact between the plunger 24 and the user. In addition, since the base end of the cartridge 16 does not protrude from the base end face of the reservoir 22, it is easier to attach the cartridge 16 to the drive unit 18.

[0109] As shown in Figure 7, the drive mechanism 40 includes a plunger pressing part 403 that moves axially to contact the plunger 24 and push it toward the tip. With this configuration, the length of the plunger 24 can be made shorter than the length of the reservoir 22, and the plunger pressing part 403 can effectively move the plunger 24 and discharge the liquid chemical M.

[0110] As shown in Figure 6, in the initial state before the drive mechanism 40 is driven, the plunger 24 and the plunger pressing portion 403 are spaced apart from each other in the axial direction when the drive unit 18 and the cartridge 16 are assembled.

[0111] With this configuration, when assembling the drive unit 18 and the cartridge 16, it is possible to effectively prevent the plunger pressing portion 403 and the plunger 24 from coming into contact with each other.

[0112] As shown in Figure 7, when the drive mechanism 40 moves toward the plunger 24, the plunger pressing portion 403 and the plunger 24 are provided with a contact portion 90 that engages with each other. The contact portion 90 has a first contact portion 921 provided on the plunger 24 and protruding in the axial direction, and a second contact portion 922 provided on the plunger pressing portion 403, which is recessed in the axial direction into which the first contact portion 921 is inserted.

[0113] With this configuration, the contact portion 90 can effectively transmit the axial force associated with the movement of the drive mechanism 40 toward the tip to the plunger 24. Since the insertion of the first contact portion 921 into the second contact portion 922 effectively prevents relative movement between the plunger pressing portion 403 and the plunger 24 in a direction intersecting the axial direction, the plunger 24 can be stably pushed toward the tip.

[0114] The reservoir 22 includes a guide portion 223. The guide portion 223 penetrates the plunger 24 in the axial direction and includes a guide hole 32 into which the plunger 24 and the plunger pressing portion 403 are inserted.

[0115] With this configuration, the guide hole 32 effectively supports at least one of the plunger 24 and the plunger pressing portion 403 in the axial direction, thereby improving the straightness of the plunger 24.

[0116] As shown in Figure 12, the plunger rod 242 is inserted into the guide hole 32, and the plunger 24 is pushed toward the tip by the plunger pressing part 403. When the plunger body 241 moves to the tip of the chamber 28, the base end of the plunger rod 242 and the tip of the plunger pressing part 403 are inserted into the guide hole 32.

[0117] With this configuration, when the plunger 24 moves, the plunger rod 242 is effectively supported by the guide portion 223, and when the plunger 24 pushes out all of the drug solution M in the drug chamber 28, the plunger pressing portion 403 is effectively supported by the guide portion 223 together with the plunger 24. Furthermore, in the drug solution dispensing device 10, the plunger pressing portion 403, which is a component of the drive unit 18, also serves as a part of the plunger 24, allowing the plunger 24 to be shortened, thus contributing to the miniaturization of the cartridge 16.

[0118] As shown in Figure 6, the cartridge 16 is housed in the mounting portion 20 of the drive unit 18, and the reservoir 22 is equipped with a sealing member 34 that contacts the mounting portion 20.

[0119] With this configuration, the sealing member 34 effectively maintains liquid tightness between the cartridge 16 and the drive unit 18.

[0120] As shown in Figure 4, the drive unit 18 includes a drive mechanism 40 for driving the plunger 24 in the axial direction, and the drive mechanism 40 has a plunger pressing portion 403 that moves in the axial direction to bias the plunger 24 toward the tip.

[0121] With this configuration, when assembling the cartridge 16 and the drive unit 18, contact between the drive mechanism 40 and the plunger 24 is effectively suppressed.

[0122] As shown in Figure 6, the plunger 24 is formed to a length that can be accommodated inside the reservoir 22. As shown in Figure 7, as the drug solution M is introduced into the drug chamber 28 of the reservoir 22, the plunger 24 protrudes from the reservoir 22 toward the base end, and as shown in Figure 12, the plunger 24 moves toward the tip by being pressed by the drive mechanism 40.

[0123] With this configuration, the plunger 24 does not protrude outside the reservoir 22, effectively preventing the user from accidentally coming into contact with the plunger 24 when handling the cartridge 16. Furthermore, the cartridge 16 can be made smaller.

[0124] While this disclosure has been described in detail, it is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of this disclosure or from the intent of this disclosure derived from the claims and their equivalents. These embodiments can also be implemented in combination. For example, the order of operations and processes in the embodiments described above are given as examples only and are not limited thereto. The same applies when numerical values ​​or mathematical formulas are used in the description of the embodiments described above.

Claims

1. A drug dispensing device comprising: a cartridge having a reservoir capable of containing a drug solution and a plunger provided to be movable in the axial direction of the reservoir for discharging the drug solution from the reservoir; and a drive unit having a drive mechanism for driving the plunger in the axial direction, the cartridge being detachable, wherein the plunger is of a length that can be accommodated inside the reservoir, and the drive mechanism biases the plunger toward the tip.

2. A drug dispensing device according to claim 1, wherein the drive mechanism comprises a plunger pressing portion that moves in the axial direction, contacts the plunger, and pushes it toward the tip.

3. A drug dispensing device according to claim 2, wherein the drive unit and the cartridge are assembled, and in the initial state before the drive mechanism is driven, the plunger and the plunger pressing portion are arranged to be spaced apart from each other in the axial direction.

4. A drug dispensing device according to claim 2 or 3, wherein when the drive mechanism moves toward the plunger, the plunger pressing portion and the plunger come into contact with each other, the drug dispensing device comprising: a first contact portion provided on one of the plunger pressing portion and the plunger and protruding in the axial direction; and a second contact portion provided on the other of the plunger pressing portion and the plunger, recessed in the axial direction into which the first contact portion is inserted.

5. A drug solution dispensing device according to claim 2, wherein the reservoir comprises: a cylindrical reservoir body having a drug chamber inside into which the drug solution is introduced; a reservoir opening opening at the base end of the reservoir body; and a guide portion provided in the reservoir opening, wherein the guide portion penetrates the plunger in the axial direction and has a guide hole into which at least one of the plunger and the plunger pressing portion is inserted.

6. A drug dispensing device according to claim 5, wherein the plunger comprises a plunger body inserted liquid-tightly into the drug chamber and a plunger rod extending axially from the plunger body, the plunger rod being inserted into the guide hole, and the plunger being pushed toward the tip by the plunger pressing portion, and the plunger body moving to the tip of the drug chamber, the base end of the plunger rod and the tip of the plunger pressing portion being inserted into the guide hole.

7. A drug dispensing device according to claim 1, wherein the cartridge is mounted on the mounting portion of the drive unit, and the reservoir is equipped with a sealing member that contacts the mounting portion.

8. A drive unit to which a cartridge having a reservoir capable of containing a liquid medicine and a plunger disposed in the reservoir can be attached and detached, comprising a drive mechanism for driving the plunger in the axial direction, wherein the drive mechanism has a plunger pressing portion that moves in the axial direction to bias the plunger toward the tip.

9. A cartridge that is detachable from a drive unit, the drive unit comprising a reservoir capable of containing a chemical solution and a plunger provided to be movable in the axial direction of the reservoir for discharging the chemical solution from the reservoir, wherein the plunger has a length that can be accommodated inside the reservoir.

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