Drug solution administration device

Abstract

A drug solution administration device 1 comprises a backward movement restriction section 42 for restricting backward movement of a feed screw 38, which can occur when the feed screw 38 receives the reaction force applied to a push member 11 from a gasket 18 that pushes out a drug solution 2 that is in a barrel 13. The backward movement restriction section 42, when a predetermined reaction force or above is applied to the feed screw 38, allows the feed screw 38 to move backward a distance exceeding the meshing width between a motor-side gear 36 and a feed screw coupling gear 37 of the feed screw 38, thus causing the disengagement of the meshing between the feed screw coupling gear 37 and a motor-side gear 36.

Description

Medical solution administration device

[0001] The present invention relates to a drug solution administration device for administering a drug solution filled in a drug solution container.

[0002] Conventionally, so-called syringe pump-type drug solution administration devices for administering a drug solution filled in a drug solution container have been known. For example, Patent Document 1 (JP 2018-507747 A) discloses a drug delivery pump (drug solution administration device) having a structure in which a drive mechanism (100) including an electric actuator (101) such as a motor controls the speed of movement of a piston (110, 1110, 2110) (a plunger seal (60) in a barrel (58)) to push a fluid (drug solution) from a drug chamber (21) defined in a drug container (50).

[0003] Special Table 2018-507747

[0004] In a drug solution administration device such as that described in Patent Document 1, if a blockage occurs in the delivery path for drug solution pushed out from a drug container, the plunger, which continues to advance toward the distal end by the drive mechanism, increases internal pressure (fluid pressure) in the upstream (proximal end) portion of the delivery path from the blockage, which may result in leakage of the drug solution. Furthermore, if the blockage in the delivery path is suddenly relieved due to such an increase in internal pressure, the object causing the blockage may flow further downstream (distal end), or an unintended sudden change (rapid increase) in the drug solution dosage may occur. Therefore, an object of the present invention is to provide a drug solution administration device for administering drug solution filled in a drug solution container, which provides increased safety in the event of a blockage in the delivery path.

[0005] The above object can be achieved by the following: (1) A drug solution administration device comprising: a drug solution container comprising a barrel filled with a drug solution and having a tip opening from which the drug solution can be dispensed, a gasket slidable inside the barrel and pushing out the drug solution inside the barrel, a plunger capable of pressing the gasket, and a drive mechanism for advancing the plunger toward the tip side of the barrel, wherein the drive mechanism has a motor that generates drive torque, a shaft-shaped feed screw that rotates upon receiving the drive torque, a transmission unit that transmits the drive torque from the motor to the feed screw, and a threaded portion that is provided on the plunger and screws into the feed screw, and advances the plunger as the feed screw rotates, and the feed screw receives a reaction force applied to the plunger from the gasket, and the transmission unit comprises a feed screw coupling gear coaxially fixed to the feed screw, and a motor-side gear that meshes with the feed screw coupling gear and transmits the drive torque to the feed screw coupling gear, Furthermore, the drug solution administration device is equipped with a rearward movement regulating section that regulates the rearward movement of the feed screw when it receives the reaction force, and the rearward movement regulating section allows the feed screw to move rearward a distance that exceeds the meshing width between the feed screw connecting gear and the motor side gear when a predetermined or greater reaction force is applied to the feed screw, thereby releasing the meshing between the feed screw connecting gear and the motor side gear.

[0006] (2) In the drug solution administration device described in (1) above, it is preferable that the rearward movement restricting portion be able to abut or engage with the feed screw, and that the drug solution administration device be configured such that, when a predetermined or greater reaction force is applied to the feed screw, the abutment or engagement between the feed screw and the rearward movement restricting portion is released, and the feed screw is moved rearward a distance exceeding an engagement width between the feed screw coupling gear and the motor-side gear, thereby releasing the engagement between the feed screw coupling gear and the motor-side gear. (3) In the drug solution administration device described in (2) above, it is preferable that the drive mechanism have a rotation restricting portion that restricts rotation of the plunger relative to the feed screw, and that the plunger is advanced in accordance with rotation of the feed screw while rotation relative to the feed screw is restricted by the rotation restricting portion. (4) In the medicinal solution administration device described in (2) or (3) above, it is preferable that the rearward movement restricting portion is broken by a reaction force equal to or greater than the predetermined value to release contact or engagement with the feed screw, and the reaction force causes the feed screw to move rearward a distance that exceeds the meshing width between the feed screw coupling gear and the motor-side gear, thereby releasing the meshing between the feed screw coupling gear and the motor-side gear. (5) In the medicinal solution administration device described in any of (2) to (4) above, it is preferable that the rearward movement restricting portion is disposed rearward of the feed screw coupling gear. (6) In the medicinal solution administration device described in (5) above, it is preferable that the rearward movement restricting portion includes a support plate portion that abuts against the rear end of the feed screw to which the feed screw coupling gear is fixed. (7) In the drug solution administration device described in (6) above, the rearward movement restricting portion releases contact with the feed screw when the support plate portion is broken by a reaction force equal to or greater than the predetermined value, and the reaction force causes the feed screw to move rearward a distance that exceeds the meshing width between the feed screw coupling gear and the motor-side gear, thereby releasing the meshing between the feed screw coupling gear and the motor-side gear, and further, it is preferable that the support plate portion has a fragile portion that serves as a starting point for breakage due to a reaction force equal to or greater than the predetermined value. (8) In the drug solution administration device described in (6) or (7) above, it is preferable that the support plate portion is made of resin.

[0007] The medicinal liquid administration device of the present invention includes a rearward movement restricting portion that restricts rearward movement of the feed screw when a reaction force applied from the gasket to the plunger is received, and the rearward movement restricting portion allows the feed screw to move rearward a distance that exceeds the meshing width between the feed screw coupling gear and the motor-side gear when a reaction force of a predetermined magnitude or greater is applied to the feed screw, thereby releasing the meshing between the feed screw coupling gear and the motor-side gear. This increases safety in the medicinal liquid administration device in the event of a blockage in the liquid delivery path.

[0008] FIG. 1 is a perspective view showing the basic configuration of an embodiment of a drug solution administration device of the present invention. FIG. 2 is a front view of the drug solution administration device shown in FIG. 1. FIG. 3 is a plan view of the drug solution administration device shown in FIG. 1. FIG. 4 is a schematic cross-sectional view taken along line A-A in FIG. 2. FIG. 5 is an enlarged partial schematic view showing the structure of the rotation restricting portion and the threaded portion in the cross-sectional view taken along line B-B in FIG. 4. FIG. 6 is an enlarged partial cross-sectional schematic view illustrating the configuration of a rearward movement restricting portion in an embodiment of a drug solution administration device of the present invention. FIG. 7 is an enlarged partial cross-sectional schematic view illustrating the operation of the rearward movement restricting portion of the drug solution administration device shown in FIG. 6. FIG. 8 is a schematic cross-sectional view corresponding to FIG. 4, showing another embodiment of a drug solution administration device of the present invention. FIG. 9 is an enlarged partial cross-sectional schematic view illustrating the configuration of a rearward movement restricting portion in another embodiment of a drug solution administration device of the present invention. FIG. 10 is an enlarged schematic front view illustrating the configuration of an optical rotation detecting portion used in an embodiment of a drug solution administration device of the present invention. FIG. 11 is a right side view of FIG. 10. FIG. 12 is an enlarged schematic front view illustrating the configuration of an optical rotation detecting portion used in another embodiment of a drug solution administration device of the present invention. Fig. 13 is a right side view of Fig. 12. Fig. 14 is a front schematic view showing a state in which the drug solution administration device and administration instrument of the present invention are attached to a living body site. Fig. 15 is a partial enlarged sectional schematic view illustrating the configuration of a rearward movement restriction portion in another embodiment of the drug solution administration device of the present invention. Fig. 16 is a partial enlarged sectional schematic view illustrating the configuration of a rearward movement restriction portion in another embodiment of the drug solution administration device of the present invention. Fig. 17 is a partial enlarged sectional schematic view illustrating the operation of the rearward movement restriction portion of the drug solution administration device shown in Fig. 16. Fig. 18 is a partial enlarged sectional schematic view illustrating the configuration of a rearward movement restriction portion in another embodiment of the drug solution administration device of the present invention. Fig. 19 is a partial enlarged sectional schematic view illustrating the operation of the rearward movement restriction portion of the drug solution administration device shown in Fig. 18. Fig. 20 is a partial enlarged sectional schematic view illustrating the configuration of a rearward movement restriction portion in another embodiment of the drug solution administration device of the present invention. Fig. 21 is a partial enlarged sectional schematic view illustrating the operation of the rearward movement restriction portion of the drug solution administration device shown in Fig. 20. FIG. 22 is an enlarged partial cross-sectional schematic view illustrating the configuration of a rearward movement restricting portion in another embodiment of the drug solution administration device of the present invention.23 is an enlarged partial schematic cross-sectional view illustrating the operation of the rearward movement restricting portion of the drug solution administration device shown in FIG. 22. FIG.

[0009] The medicinal solution administration device of the present invention will be described with reference to an embodiment shown in the drawings. As shown in Figures 1 to 7, the medicinal solution administration device 1 of the present invention includes a barrel 13 filled with medicinal solution 2 and having a tip opening 12 from which the medicinal solution 2 can be dispensed, a medicinal solution container 10 including a gasket 18 slidable within the barrel 13 and pushing out the medicinal solution 2 from the barrel 13, a plunger 11 capable of pressing the gasket 18, and a drive mechanism 30 for advancing the plunger 11 toward the tip of the barrel 13. The drive mechanism 30 includes a motor 31 for generating a drive torque, a shaft-shaped feed screw 38 that rotates upon receiving the drive torque, a transmission unit 41 for transmitting the drive torque from the motor 31 to the feed screw 38, and a threaded portion 19 provided on the plunger 11 and threadedly engaging with the feed screw 38. The drive mechanism 30 advances the plunger 11 as the feed screw 38 rotates, and the feed screw 38 receives a reaction force applied to the plunger 11 by the gasket 18. The transmission unit 41 includes a feed screw coupling gear 37 coaxially fixed to the feed screw 38, and a motor-side gear 36 that meshes with the feed screw coupling gear 37 and transmits drive torque to the feed screw coupling gear 37. The drug solution administration device 1 further includes a rearward movement restriction unit 42 that restricts rearward movement of the feed screw 38 that receives a reaction force, and when a reaction force of a predetermined magnitude or greater is applied to the feed screw 38, the rearward movement restriction unit 42 allows rearward movement of the feed screw 38 a distance that exceeds the meshing width between the feed screw coupling gear 37 and the motor-side gear 36, thereby releasing the meshing between the feed screw coupling gear 37 and the motor-side gear 36.

[0010] In this embodiment, the rearward movement regulating portion 42 can abut or engage with the feed screw 38, and when a reaction force greater than a predetermined value is applied to the feed screw 38, the drug solution administration device 1 releases the abutment or engagement between the feed screw 38 and the rearward movement regulating portion 42, and moves the feed screw 38 rearward a distance that exceeds the meshing width between the feed screw connecting gear 37 and the motor side gear 36, thereby releasing the meshing between the feed screw connecting gear 37 and the motor side gear 36.

[0011] Although illustrations and detailed description are omitted, the medicinal liquid administration device 1 of this embodiment, like the medicinal liquid administration device proposed by the present applicant in WO 2020 / 202922, includes a detection unit that detects the detection target portion of the plunger 11 and detects completion of medicinal liquid delivery based on the detection result, a control unit that controls the operation of the medicinal liquid administration device 1 including the drive mechanism 30, a power supply unit that supplies the power necessary for the operation of the drive mechanism 30, the control unit, etc. The control unit can be configured, for example, by a known microcomputer (electronic circuit elements) equipped with a CPU, RAM, ROM, etc., and comprehensively controls the operation of the medicinal liquid administration device 1 including the drive mechanism 30, the detection unit, the power supply unit, and the optical rotation detection unit 32 described below.

[0012] The drug solution administration device 1 of this embodiment includes a housing 50 that can accommodate the drug solution container 10, the plunger 11, the drive mechanism 30, and the rearward movement restricting portion 42.

[0013] As shown in FIGS. 1 to 4 , the housing 50 of this embodiment includes a first housing member (front case) 51 and a second housing member (rear case) 52, and defines an internal storage space 53. In this embodiment, the housing 50 (first housing member 51 and second housing member 52) is formed of a light-transmitting material that allows visible light to pass through, making the interior of the housing 50 visible from the outside. The housing (first housing member, second housing member) may be formed of a semi-light-transmitting material, a light-non-light-transmitting material, or a light-slightly light-transmitting material. In such cases, a window or the like may be provided in a desired location of the housing to allow the interior to be viewed. The storage space 53 of the housing 50 accommodates a chassis 54 that can be fixed to the housing 50 and that can hold the drug solution container 10, the plunger 11, the drive mechanism 30 (and further, the detection unit, control unit, power supply unit), and the like.

[0014] In this embodiment, the chassis 54 is made of a hard resin material and includes a substantially plate-shaped substrate portion 55 that forms the lower portion (bottom), and a base end wall portion 56 that extends upward from the base end portion of the substrate portion 55. The chassis 54 may be made of a light-transmitting material to improve visibility inside the housing 50, or may be made of a light-semitransmitting material, a light-non-transmitting material, or a light-difficulty-transmitting material.

[0015] A base end opening 57 for inserting the chassis 54 into the accommodation space 53 of the housing 50 is formed on the base end side in the longitudinal direction of the first housing member 51 of the housing 50. The base end opening 57 of the first housing member 51 is closed by the second housing member 52 when the chassis 54 is accommodated in the accommodation space 53.

[0016] As will be described later (see FIG. 14 ), the drug solution administration device 1 of this embodiment is used by being attached to a living body part 90, and the housing 50 has a lower surface part (living body attachment side surface part) 58 that is attached to the living body part 90, an upper surface part 59 that faces the lower surface part 58 across the accommodation space 53, and a pair of side surfaces 60, 60 that connect both sides of the lower surface part 58 and the upper surface part 59. Note that the lower surface part 58 and the upper surface part 59 are connected to the side surfaces 60, 60 smoothly (without edges) in order to reduce stress on the living body (patient) to which the drug solution administration device 1 is attached and to prevent damage to the drug solution administration device 1, and therefore the boundaries between them are not necessarily clear. The contact surface (lower surface 58) of the housing 50 of the drug solution administration device 1 with the biological part 90 is provided with a sheet-like adhesive part (not shown) that can be attached to the surface of the biological part 90, and in the initial state before the drug solution administration device 1 is attached to the user (patient), a peelable protective sheet is attached to the adhesive surface of the adhesive part.

[0017] The liquid medicine container 10 of this embodiment is a so-called prefilled type liquid medicine container, and as shown in Fig. 4, includes a cylindrical barrel 13 to be filled with the liquid medicine, and the liquid medicine 2 is pre-filled into the inner cavity 14 of the barrel 13 of the liquid medicine container 10. The tip of the liquid medicine container 10 is provided with a tip opening 12 for discharging the liquid medicine 2 (administering it to a patient). The barrel 13 of the liquid medicine container 10 is preferably made of an optically transparent material. This allows the interior of the liquid medicine container 10 (the administration state of the liquid medicine 2) to be visually observed from the outside.

[0018] Various types of medicinal liquids can be used as the medicinal liquid 2 (liquid medicine) filled in the medicinal liquid container 10, including, for example, protein preparations, narcotic analgesics, diuretics, insulin, analgesics, anti-cancer treatment drugs, local anesthetics, HIV drugs, iron chelating drugs, pulmonary hypertension treatment drugs, vitamins, and medicinal liquids containing antibiotics.

[0019] When not in use, a sealing member 15 is disposed at a tip opening (discharge port) 12 formed at the tip of the drug solution container 10 to prevent leakage of the drug solution 2. As shown in FIG. 4 , the tip opening 12 of the drug solution container 10 is disposed so as to protrude to the outside from the housing 50 (first housing member 51). The tip of the drug solution container 10 protruding from the housing 50 (first housing member 51) is provided with a connector portion (drug solution container-side connector portion) 16 that can be connected to a tube 101 (see FIG. 14 ) connected to the administration instrument 100, which will be described later. A liquid delivery path for the drug solution 2 is formed in the portion of the drug solution container 10 extending from the tip opening 12 to the tip side (downstream of the drug solution 2), including the connector portion 16 and the tube 101.

[0020] The liquid medicine container 10 includes a gasket 18 that is slidable inside the barrel 13 and pushes out the liquid medicine 2 inside the barrel 13. The gasket 18 can be made of a flexible resin material, such as rubber or elastomer. The outer periphery of the gasket 18 is in liquid-tight contact with the inner periphery of the barrel 13 of the liquid medicine container 10, thereby liquid-tightly sealing the base end side of the lumen 14 filled with the liquid medicine 2. In this embodiment, the shape of the tip of the gasket 18 is formed to be substantially the same as the shape of the inside of the tip of the liquid medicine container 10.

[0021] A generally cylindrical plunger 11 is inserted into the lumen 14 of the barrel 13 of the liquid medicine container 10 from the proximal end side (see FIG. 4 ). The tip of the plunger 11 is attached to a gasket 18 that is slidable along the inner wall of the liquid medicine container 10 and is capable of pressing against the gasket 18. A lead screw 38 is inserted into the lumen 20 of the plunger 11 from the proximal end side, and is threadedly engaged with the lead screw 38 at a threaded portion (female threaded portion) 19 provided within the lumen 20. More specifically, the inner shape (inner diameter) of the lumen 20 of the plunger 11 is larger than the outer shape (outer diameter) of the lead screw 38, and the threaded portion (female threaded portion) 19 that threadably engages with the lead screw 38 is formed within the lumen 20 (here, near the proximal end) so as to protrude inward (see also FIG. 5 ).

[0022] The drive mechanism 30 includes a motor 31 that generates a drive torque, a shaft-shaped feed screw 38 that rotates upon receiving the drive torque, a transmission unit 41 that transmits the drive torque from the motor 31 to the feed screw 38, and a screw-threaded unit 19 that is provided on the plunger 11 as described above and screws into the feed screw 38.

[0023] The transmission unit 41 includes a feed screw connection gear 37 coaxially fixed to the feed screw 38 and a motor-side gear 36 that meshes with the feed screw connection gear 37 and transmits driving torque to the feed screw connection gear 37. More specifically, in this embodiment, the transmission unit 41 includes a motor connection gear 35 connected to the base end of the rotation shaft of the motor 31, a motor-side gear (intermediate gear) 36 that is adjacent to the motor connection gear 35 and arranged to mesh with the motor connection gear 35, and a feed screw connection gear 37 that is fixed coaxially to the feed screw 38 and meshes with the motor-side gear 36. Note that the transmission unit is not limited to the above-described configuration (including three gears) and may include multiple intermediate gears (gears provided between the motor connection gear and the feed screw connection gear). In this case, the gear among the multiple intermediate gears that meshes with the feed screw connection gear and transmits driving torque to the feed screw connection gear is the motor-side gear. Alternatively, the motor coupling gear and the feed screw coupling gear may be directly meshed without providing an intermediate gear, in which case the motor coupling gear also functions as a motor-side gear that transmits drive torque to the feed screw coupling gear.

[0024] The feed screw 38 is rotatably disposed on the chassis 54. The feed screw 38 has a male thread portion on its outer circumferential surface, which is threadedly engaged (connected) with a threaded portion (female thread portion) 19 provided near the base end of the plunger 11.

[0025] As shown in Figure 5, the drive mechanism 30 of this embodiment has a rotation restriction unit 43 that restricts the rotation of the plunger 11 relative to the feed screw 38, and the plunger 11 is advanced in accordance with the rotation of the feed screw 38 while the rotation of the plunger 11 relative to the feed screw 38 is restricted by the rotation restriction unit 43.

[0026] Specifically, as shown in Fig. 5 , the rotation restricting unit 43 of this embodiment includes a pair of rotation restricting recesses 21, 21 provided on the outer periphery of the plunger 11 so as to extend in the axial direction (the left-right direction in Fig. 4 ), and a pair of rotation restricting protrusions 62, 62 provided on the chassis 54 and formed so as to be able to enter the rotation restricting recesses 21. As shown in Fig. 5 , the rotation restricting protrusions 62 enter (engage) with the rotation restricting recesses 21, thereby restricting the rotation of the plunger 11 relative to the feed screw 38 and allowing the plunger 11 to move (advance) in the axial direction in accordance with the rotation of the feed screw 38. It should be understood that Fig. 5 is intended to schematically explain the structure of the rotation restricting unit 43 (and the threaded portion 19), and each component is shown schematically.

[0027] As described above, the plunger 11 is immovable relative to the lead screw 38 but movable in the axial direction of the liquid medicine container 10. Rotation of the lead screw 38 causes the plunger 11 to be threaded and move in the axial direction of the liquid medicine container 10. In other words, the lead screw 38 converts the rotational motion transmitted from the motor 31 via the transmission unit 41 (motor connecting gear 35, motor-side gear (intermediate gear) 36, lead screw connecting gear 37) into linear motion, thereby advancing the plunger 11 in the longitudinal direction (axial direction of the barrel 13 of the liquid medicine container 10). As the plunger 11 advances toward the distal end of the liquid medicine container 10, the liquid medicine 2 in the lumen 14 of the barrel 13 of the liquid medicine container 10 is pushed out through the distal opening 12. In other words, rotation of the lead screw 38 causes the plunger 11 to advance relative to the lead screw 38, increasing the distance from the rear end of the lead screw 38 to the distal end of the plunger 11. Here, the rearward movement of the feed screw 38 is restricted by the rearward movement restricting portion 42 described later, so that the plunger 11 and the gasket 18 move forward, and the medicinal solution 2 is pushed out.

[0028] In the medicinal solution administration device 1, the feed screw 38 receives a reaction force applied from the gasket 18 to the plunger 11 as the plunger 11 advances as described above. In other words, the reaction force applied from the gasket 18 to the plunger 11 as the plunger 11 advances is transmitted to the feed screw 38 via the threaded portion 19.

[0029] As shown in Fig. 4, the drug solution administration device 1 includes a rearward movement restricting portion 42 that can come into contact with or engage with the feed screw 38. The rearward movement restricting portion 42 restricts the rearward movement of the feed screw 38 that has received the above-mentioned reaction force. In this embodiment, the rearward movement restricting portion 42 is disposed rearward of the feed screw coupling gear 37. More specifically, in this embodiment, the rearward movement restricting portion 42 includes a support plate portion 45 that comes into contact with a rear end portion 44 of the feed screw 38 to which the feed screw coupling gear 37 is fixed.

[0030] In the embodiment shown in FIG. 6 , the support plate 45 is a plate-shaped member made of a hard or semi-hard resin. The support plate 45 may also be made of metal, soft resin, or the like. The support plate 45 is housed in a housing 63 formed in the chassis 54. A slit (opening) 65 is provided in a base end (rear end) sidewall 64 of the housing 63 to allow the support plate 45 to break and the lead screw 38 to move rearward, as described below. The housing 63 also has a hole 67 in a tip end (front end) sidewall 66, through which the rear end 44 of the lead screw 38 can be inserted. The hole 67 also functions as a guide for moving the lead screw 38 in the axial direction (restricting movement in a direction perpendicular to the axial direction).

[0031] In the medicinal solution administration device 1 of this embodiment, when a reaction force of a predetermined magnitude or greater is applied to the feed screw 38, the abutment or engagement between the feed screw 38 and the rearward movement restricting portion 42 (restriction on rearward movement by the rearward movement restricting portion 42) is released, and the feed screw 38 moves rearward a distance exceeding the meshing width between the feed screw coupling gear 37 and the motor-side gear 36, thereby disengaging the mesh between the feed screw coupling gear 37 and the motor-side gear 36. In this embodiment, as shown in FIGS. 4 , 6 , and 7 , the rearward movement restricting portion 42 (support plate portion 45) is broken by a reaction force of a predetermined magnitude or greater, thereby releasing the abutment or engagement (here, abutment) with the feed screw 38, allowing the feed screw 38 to move rearward a distance exceeding the meshing width between the feed screw coupling gear 37 and the motor-side gear 36 due to the reaction force, thereby disengaging the mesh between the feed screw coupling gear 37 and the motor-side gear 36. This improves safety in the medicinal solution administration device 1 in the event of a blockage in the liquid delivery path.

[0032] That is, if an obstruction occurs in the liquid delivery path for the liquid medicine 2 extruded from the liquid medicine container 10, the plunger 11 (and the gasket 18) will continue to advance toward the distal end by the drive mechanism 30, causing an increase in internal pressure (liquid pressure) in the portion of the liquid delivery path upstream (proximal end) of the obstruction. Accordingly, the reaction force transmitted from the gasket 18 to the feed screw 38 via the plunger 11 (threaded portion 19) also increases. When the reaction force reaches a predetermined level or greater, the support plate portion 45 of the rearward movement restrictor 42 is destroyed, and the abutment or engagement (here, abutment) with the feed screw 38 is released. Then, as shown in FIG. 7 , the feed screw 38 moves rearward a distance exceeding the meshing width between the feed screw coupling gear 37 and the motor-side gear 36, causing the meshing between the feed screw coupling gear 37 and the motor-side gear 36 to be released. The rearward movement of the feed screw 38 may be achieved all at once by the elastic force of the gasket 18, which is an elastic member, or by the internal pressure (fluid pressure) increased by the blockage of the fluid supply path. Even if the meshing between the feed screw coupling gear 37 and the motor-side gear 36 continues after the support plate 45 is destroyed, the destruction of the support plate 45 (loss of the function of the rearward movement restricting portion 42 to restrict the rearward movement of the feed screw 38) will cause the feed screw 38 to rotate and move rearward (because its forward movement is prevented by the blockage), and eventually the meshing between the feed screw coupling gear 37 and the motor-side gear 36 will be released. As shown in FIG. 7 , the destroyed support plate 45 will leave the housing 63 through the slit 65 provided in the base-end side wall 64 of the housing 63, and will not prevent the rearward movement of the feed screw 38.

[0033] The drug solution administration device may be provided with a biasing means for moving the feed screw backward after the rearward movement restricting portion 42 abuts against or disengages from the feed screw 38. For example, as shown in Fig. 8, a compression spring 23 serving as a biasing means may be disposed between the gasket 18 and the plunger 11, and when the rearward movement restriction on the feed screw 38 by the rearward movement restricting portion 42 is released, the elastic force (restoring force) of the compression spring 23 may cause the feed screw 38 (via the plunger 11) to move backward in one go until the meshing between the feed screw connecting gear 37 and the motor-side gear 36 is released.

[0034] In the present embodiment, the strength (material, thickness, and shape) of the support plate 45 can be appropriately set to adjust the amount of reaction force required to release the contact or engagement with the feed screw 38 (to destroy the support plate 45). As shown in FIG. 9 , the support plate 45 may include a fragile portion 46 that serves as a starting point for destruction due to a reaction force greater than or equal to a predetermined value. This allows the support plate 45 to be more reliably destroyed by a predetermined reaction force, starting from the fragile portion 46, thereby further increasing safety in the event of a blockage in the liquid delivery path.

[0035] The drug solution administration device 1 of this embodiment includes a rotation detection unit 32 for detecting the rotation of the motor 31 .

[0036] The rotation detector 32 of this embodiment is an optical rotation detector 32 that optically detects the rotation of the motor 31, and is a transmissive photointerrupter in which the light emitter 33 and the light receiver 34 are provided facing each other with the detected part (in this embodiment, the blade part 40, which will be described later) in between, as shown in Figures 10 and 11. Note that, as shown in Figures 12 and 13, the optical rotation detector 32a may be a reflective photointerrupter in which the light emitter 33 and the light receiver 34 are provided on the same side (the right side in Figure 12) of the detected part (the blade part 40).

[0037] The optical rotation detector 32 detects the rotation of the motor 31 based on changes in detection light (detection light irradiated from the light emitter 33 toward the light receiver 34) (presence or absence of light reception (or difference in the amount of light received) at the light receiver 34) caused by the detected part intermittently passing between the light emitter 33 and the light receiver 34. In this embodiment, the detected part is composed of three blades 40 formed at the base end of the motor connecting gear 35 connected to the base end of the rotating shaft of the motor 31. The optical rotation detector 32 is electrically connected to the control unit, which can calculate the rotation speed of the motor 31 and determine whether the motor 31 is rotating to determine whether the administration of the medicinal solution is being performed normally. Furthermore, if it is determined that there is an abnormality in the rotation of the motor 31 (abnormal rotation speed), it can issue a warning or activate a safety device to suspend administration of the medicinal solution.

[0038] Furthermore, the rotation detection unit (optical rotation detection unit) 32 of the motor 31 can be combined with the above-described rearward movement restricting unit 42 and used to control the medicinal solution administration device 1. For example, the rotation detection unit 32 can detect a change in the rotation of the motor 31 before and after the rearward movement restricting unit 42 comes into contact with or disengages from the feed screw 38 (in this embodiment, destruction of the support plate unit 45), and by quickly stopping the drive of the motor 31 after the contact or disengagement, it is possible to prevent the motor from generating heat due to free rotation and the medicinal solution administration device 1 from operating unintentionally.

[0039] As shown in Figure 14, the drug solution administration device 1 of this embodiment is configured to be connectable to an administration instrument 100. An overview of the administration instrument 100 will be described below. The administration instrument 100 has a connector portion (administration instrument side connector portion) 102, a tube 101, a needle tube 103 that is inserted into a living body (living body part 90), and a puncture portion (cannula housing) 104.

[0040] The connector portion 102 is configured to be connectable to the medicinal solution administration device 1. Specifically, the connector portion 102 is connected to the medicinal solution administration device 1 by being fitted onto the outside of a connector portion 16 provided at the tip of the medicinal solution container 10 that protrudes outside the housing 50. Although not shown, a connecting needle portion capable of piercing a sealing member 15 arranged at the tip of the medicinal solution container 10 is arranged inside the connector portion 102. The tube 101 is communicated with the inner cavity 14 of the barrel 13 of the medicinal solution container 10 via the connecting needle portion.

[0041] A flow path (not shown) that connects the inner cavity of the tube 101 and the needle tube 103 is formed inside the puncture part 104. When the plunger 11 of the drug solution administration device 1 advances inside the drug solution container 10 with the needle tube 103 puncturing the living body, the drug solution 2 filled in the drug solution container 10 is sent to the puncture part 104 via the tube 101 and administered into the living body through the flow path formed inside the puncture part 104 and the needle tube 103.

[0042] Like the drug solution administration device 1, the administration device 100 is configured as a patch type that is attached to the user's body surface 91. A sheet-like adhesive part (not shown) that can be attached to the body surface 91 is provided on the contact surface (bottom surface) of the puncture part 104 of the administration device 100. In the initial state before the administration device 100 is attached to the user, a removable protective sheet is attached to the adhesive surface of the adhesive part.

[0043] The drug solution administration device of the present invention is not limited to the above-described embodiment. For example, in the rearward movement restricting portion 42a of the drug solution administration device shown in Fig. 15, the rear end portion 44 of the feed screw 38 and the support plate portion 45 constituting the rearward movement restricting portion 42 are engaged (fixed) by crimping (crimping portion 47) so as to be relatively rotatable. This makes it difficult for the rear end portion 44 of the feed screw 38 to be disengaged from the support plate portion 45 under normal circumstances (before the support plate portion 45 is broken by a reaction force greater than a predetermined value). Furthermore, the crimping portion 47 serves as a starting point, making it possible to more reliably break the support plate portion 45 by a reaction force greater than a predetermined value.

[0044] 16 and 17, the support plate 45 may be detached from the storage unit 63 without being destroyed, as in the case of the rearward movement restricting portion 42b of the drug solution administration device shown in FIG. 16 and 17. This avoids adverse effects caused by fragments or the like that are generated when the support plate 45 is destroyed. As shown in FIG. 16 and 17, the slit 65 of the storage unit 63 may be provided with thin-walled portions (inclined portions) 48, 48 that facilitate (guide) the detachment of the support plate 45.

[0045] 18 and 19, the rearward movement restricting portion 42c may be configured by a base end wall portion 56 of a chassis 54 that abuts or engages (here, abuts) with the rear end portion 44 of the feed screw 38. That is, in this embodiment, the rear end portion 44 of the feed screw 38 abuts or engages (here, abuts) with the base end wall portion 56 of the chassis 54, and when a reaction force of a predetermined level or greater is applied to the feed screw 38, as shown in FIG. 19, the base end wall portion 56 (the portion abutting the rear end portion 44 of the feed screw 38) breaks, and the restriction on the rearward movement of the feed screw 38 is released. Although not shown, the base end wall portion 56 may be provided with a weakened portion that serves as a starting point for breakage due to a reaction force of a predetermined level or greater.

[0046] 20 and 21 , the rearward movement restricting portion 42d of the drug solution administration device may be configured to release the restriction on the rearward movement of the feed screw 38 by deforming (breaking) the rear end portion 44 of the feed screw 38 that abuts or engages (here, abuts) with the base end wall portion 56 of the chassis 54 that constitutes the rearward movement restricting portion 42d. In other words, in this embodiment, the rearward movement restricting portion 42d is configured by the rear end portion 44 of the feed screw 38 and the base end wall portion 56 of the chassis 54 that abuts or engages with the rear end portion 44 (which may have a configuration similar to the support plate portion 45 described above). In this embodiment, a lightening portion 49 is provided in the rear end portion 44 of the feed screw 38, and when a reaction force of a predetermined magnitude or greater is applied to the feed screw 38, the rear end portion 44 of the feed screw 38 where the lightening portion 49 is provided is deformed (broken, buckled, etc.), allowing the feed screw 38 to move rearward a distance that exceeds the meshing width between the feed screw coupling gear 37 and the motor-side gear 36.

[0047] 22 and 23 , the rearward movement restricting portion 42 e can also be disposed forward of the feed screw connecting gear 37. In this embodiment, the rearward movement restricting portion 42 e is configured by a feed screw-side movement restricting portion 68 provided in a portion of the feed screw 38 forward of the feed screw connecting gear 37, and a chassis-side movement restricting portion 69 formed to extend upward from the base plate portion 55 of the chassis 54. When a reaction force of a predetermined magnitude or greater is applied to the feed screw 38, the feed screw-side movement restricting portion 68 or the chassis-side movement restricting portion 69 is destroyed (including deformation) (in this case, the chassis-side movement restricting portion 68 is destroyed), thereby allowing the feed screw 38 to move rearward a distance that exceeds the meshing width between the feed screw connecting gear 37 and the motor-side gear 36.

[0048] REFERENCE SIGNS LIST 1 drug solution administration device 2 drug solution 10 drug solution container 11 plunger 12 tip opening 13 barrel 18 gasket 19 threaded portion 30 drive mechanism 31 motor 36 motor side gear 37 feed screw connecting gear 38 feed screw 41 transmission portion 42 rearward movement regulating portion 43 rotation regulating portion 44 rear end portion 45 support plate portion 90 biological portion 100 administration instrument

Claims

1. A drug solution administration device comprising: a drug solution container comprising: a barrel filled with a drug solution and having a tip opening from which the drug solution can be dispensed; a gasket slidable inside the barrel and pushing out the drug solution inside the barrel; a plunger capable of pressing the gasket; and a drive mechanism for advancing the plunger toward the tip of the barrel, wherein the drive mechanism has a motor that generates drive torque, a shaft-shaped feed screw that rotates upon receiving the drive torque, a transmission unit that transmits the drive torque from the motor to the feed screw, and a threaded portion that is provided on the plunger and screws into the feed screw, and advances the plunger as the feed screw rotates, and the feed screw receives a reaction force applied to the plunger from the gasket, and the transmission unit comprises a feed screw coupling gear fixed coaxially to the feed screw, and a motor-side gear that meshes with the feed screw coupling gear and transmits the drive torque to the feed screw coupling gear, Furthermore, the drug solution administration device is equipped with a rearward movement regulating section that regulates the rearward movement of the feed screw when it receives the reaction force, and the rearward movement regulating section allows the feed screw to move rearward a distance that exceeds the meshing width between the feed screw connecting gear and the motor side gear when a reaction force greater than a predetermined value is applied to the feed screw, thereby releasing the meshing between the feed screw connecting gear and the motor side gear.

2. The drug solution administration device of claim 1, wherein the rearward movement regulating portion is capable of abutting or engaging with the feed screw, and when a reaction force greater than a predetermined value is applied to the feed screw, the drug solution administration device releases the abutment or engagement between the feed screw and the rearward movement regulating portion, and moves the feed screw rearward a distance that exceeds the meshing width between the feed screw coupling gear and the motor side gear, thereby releasing the meshing between the feed screw coupling gear and the motor side gear.

3. The drug solution administration device described in claim 2, wherein the drive mechanism has a rotation regulating section that regulates the rotation of the plunger relative to the feed screw, and the plunger is advanced in accordance with the rotation of the feed screw while being restricted in rotation relative to the feed screw by the rotation regulating section.

4. A drug solution administration device as described in claim 2 or 3, wherein the rearward movement regulating portion is broken by a reaction force equal to or greater than the specified value, thereby releasing contact or engagement with the feed screw, and the reaction force causes the feed screw to move rearward a distance exceeding the meshing width between the feed screw connecting gear and the motor side gear, thereby releasing the meshing between the feed screw connecting gear and the motor side gear.

5. A medicinal solution administration device as described in claim 2 or 3, wherein the rearward movement restricting portion is disposed rearward of the feed screw connecting gear.

6. A drug solution administration device as described in claim 5, wherein the rearward movement restriction portion comprises a support plate portion that abuts against the rear end portion of the feed screw to which the feed screw connecting gear is fixed.

7. The rearward movement restricting portion releases contact with the feed screw when the support plate portion is destroyed by a reaction force greater than the specified value, and the reaction force causes the feed screw to move rearward a distance that exceeds the meshing width between the feed screw connecting gear and the motor side gear, thereby releasing the meshing between the feed screw connecting gear and the motor side gear, and the support plate portion is further provided with a weak portion that serves as the starting point for destruction due to a reaction force greater than the specified value.

8. The drug solution administration device according to claim 6, wherein the support plate portion is made of resin.

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