Syringe pump

Abstract

To provide a syringe pump to which a syringe can be stably fitted.SOLUTION: A syringe pump comprises: a barrel receiving part 51 comprising a first surface 61 opposed to a cylindrical part of a barrel, and on which the barrel is placed; and a barrel positioning part 52 extending in a direction orthogonal to the first surface 61, forming a corner part 71 with the first surface 61, comprising a second surface 62 opposed to a flange part of the barrel, and positioning the barrel in an axial direction of the cylindrical part. The corner part 71 is provided with a chamfered shape so as not to protrude from a virtual curved surface connecting the first surface 61 and the second surface 62 with a radius of curvature of 2.3 mm.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] This invention relates to a syringe pump.

Background Art

[0002] For example, Japanese Unexamined Patent Application Publication No. 2021-97835 (Patent Document 1) discloses a syringe pump having a barrel receiving portion and a barrel groove portion. The barrel receiving portion is formed of a concave surface that contacts the lower portion of the cylindrical portion of the barrel, and the cylindrical portion of the barrel is placed thereon. The barrel groove portion is provided continuously at the end of the barrel receiving portion, and the flange portion of the barrel is inserted therein.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As disclosed in the above Patent Document 1, a syringe pump for injecting a chemical solution filled in a syringe is known. In such a syringe pump, if the barrel of the syringe is not placed in an appropriate posture with respect to the barrel receiving portion, the attachment of the syringe may become unstable, and the appropriate injection operation of the chemical solution may be hindered.

[0005] Therefore, an object of this invention is to solve the above problems and provide a syringe pump capable of stably attaching a syringe.

Means for Solving the Problems

[0006] A syringe pump according to this invention comprises a barrel support portion having a first surface facing the cylindrical portion of the barrel on which the barrel is placed, and a barrel positioning portion having a second surface extending in a direction perpendicular to the first surface, forming a corner with the first surface, and facing the flange portion of the barrel, for positioning the barrel in the axial direction of its cylindrical portion. The corner is provided with a chamfered shape so as not to protrude from a virtual curved surface connecting the first and second surfaces with a radius of curvature of 2.3 mm.

[0007] With this syringe pump configuration, the corners formed by the first and second surfaces are provided with a chamfered shape that does not protrude from the 2.3 mm virtual curved surface, thereby preventing interference between the corners of the barrel's cylindrical and flange portions. This allows the syringe to be stably attached to the syringe pump.

[0008] Preferably, when viewed in the axial direction of the cylindrical portion of the barrel placed on the barrel support, the corner extends in an arc shape. The chamfered shape is provided continuously between one end and the other end of the arc-shaped corner.

[0009] With a syringe pump configured in this way, it is possible to prevent the corner portion between the cylindrical portion and the flange portion of the barrel from interfering with the corner portion, across the arc-shaped corner portion.

[0010] Preferably, the syringe pump further includes a barrel holding portion that presses the cylindrical portion of the barrel toward the first surface and holds the barrel. The chamfered shape is provided so as not to overlap with the barrel holding portion when viewed from the front of the first surface.

[0011] With a syringe pump configured in this way, the syringe can be attached to the syringe pump even more stably by bringing the cylindrical portion of the barrel into contact with the first surface directly below the barrel holding portion. [Effects of the Invention]

[0012] As described above, according to this invention, it is possible to provide a syringe pump that can securely attach a syringe. [Brief explanation of the drawing]

[0013] [Figure 1] This is a perspective view showing a syringe pump and a syringe attached to the syringe pump in an embodiment of the present invention. [Figure 2] This is a cross-sectional view of the syringe as seen in the direction of the arrow along the line II-II in Figure 1. [Figure 3] Figure 1 is a perspective view showing the barrel support section of the syringe pump. [Figure 4] This is a plan view showing the barrel support section of the syringe pump in Figure 1. [Figure 5] This is a cross-sectional view of the barrel support portion as seen in the direction of the arrow on the VV line in Figure 4. [Figure 6] This figure shows the state of the syringe attached to the syringe pump, viewed in the direction indicated by arrow VI in Figure 3. [Figure 7] This is a cross-sectional view showing the syringe mounting state as seen in the direction of the arrow along the line VII-VII in Figure 6. [Figure 8] This is a cross-sectional view showing the corner of the barrel support section in Figure 7. [Figure 9] This is a cross-sectional view showing a modified example of the corner portion of the barrel support in Figure 7. [Modes for carrying out the invention]

[0014] Embodiments of this invention will be described with reference to the drawings. In the drawings referred to below, the same or equivalent components are given the same numbers.

[0015] Figure 1 is a perspective view showing a syringe pump and a syringe attached to the syringe pump in an embodiment of this invention. Figure 2 is a cross-sectional view showing the syringe as seen in the direction of the arrow along line II-II in Figure 1.

[0016] In this specification, for the sake of convenience in explaining the structures of the syringe 10 and the syringe pump 100, the axis extending in the axial direction of the syringe 10 (the cylindrical portion 23 of the barrel 20 to be described later) in the state of being attached to the syringe pump 100 is referred to as the "Z-axis", the axis orthogonal to the Z-axis and extending in the attachment direction of the syringe 10 with respect to the syringe pump 100 is referred to as the "Y-axis", and the axis orthogonal to the Z-axis and the Y-axis is referred to as the "X-axis".

[0017] Referring to FIGS. 1 and 2, first, the structure of the syringe 10 applied to the syringe pump 100 in the present embodiment will be described. The syringe 10 includes a barrel 20 and a plunger rod 30.

[0018] The barrel 20 has a cylindrical outer shape as a whole. The barrel 20 is made of a transparent or translucent resin such as polypropylene. The barrel 20 has a cylindrical portion 23 and a flange portion 21. The cylindrical portion 23 and the flange portion 21 are integrally formed of the above resin.

[0019] The cylindrical portion 23 has a cylindrical shape centered on the axis extending in the Z-axis direction. The inside of the cylindrical portion 23 is filled with a chemical solution. At one end (tip) of the cylindrical portion 23 in the Z-axis direction, an injection port 22 for injecting the chemical solution is provided. The other end (rear end) of the cylindrical portion 23 in the Z-axis direction is open. A lubricating oil such as silicone oil may be applied to the inner peripheral surface of the cylindrical portion 23.

[0020] The flange portion 21 extends in a flange shape outward in the radial direction of the cylindrical portion 23 from the other end of the cylindrical portion 23. The flange portion 21 extends from the other end of the cylindrical portion 23 to both sides in the X-axis direction. The flange portion 21 has a plate shape in which the axial direction (Z-axis direction) of the cylindrical portion 23 is the thickness direction, and is connected to the other end of the cylindrical portion 23.

[0021] The cylindrical portion 23 has an outer circumferential surface 26. The flange portion 21 has an end face 27. The end face 27 is made of a plane perpendicular to the Z axis (X-axis-Y-axis plane) and faces one end of the cylindrical portion 23 in the Z-axis direction. The end face 27 forms a corner 28 with the outer circumferential surface 26. The end face 27 is connected to the outer circumferential surface 26 via the corner 28. The corner 28 is made of a curved surface. As shown in Figure 2, when the barrel 20 is cut by a plane containing the central axis of the cylindrical portion 23, the corner 28 has a cross-sectional shape that extends between the outer circumferential surface 26 and the end face 27, drawing an arc centered on the outside of the cylindrical portion 23.

[0022] A response unit 40 is attached to the outer circumferential surface 26 of the cylindrical portion 23. The response unit 40 is composed of an RFID (Radio Frequency Identification) tag. The RFID tag has a circuit chip and a sheet-shaped loop antenna connected to the circuit chip, and wirelessly transmits the data recorded on the circuit chip by electromagnetic induction of the loop antenna. The data recorded on the circuit chip includes information about the barrel 20 and the plunger rod 30, information about the drug solution to be filled into the barrel 20, or information about the drug solution administration conditions.

[0023] The plunger rod 30 is fitted into the inside of the barrel 20 from the other end of the cylindrical portion 23. The plunger rod 30 extends axially in the Z-axis direction. A gasket portion 32 is provided at one end (tip) of the plunger rod 30. The gasket portion 32 is made of an elastic material such as vulcanized rubber or thermoplastic elastomer. The gasket portion 32 is in sliding contact with the inner circumferential surface of the cylindrical portion 23. A rod flange portion 31 is provided at the other end (rear end) of the plunger rod 30. The parts of the plunger rod 30 other than the gasket portion 32 are made of a resin such as polypropylene.

[0024] Next, the structure of the syringe pump 100 in this embodiment will be described. Figure 3 is a perspective view showing the barrel support portion of the syringe pump in Figure 1. Figure 4 is a plan view showing the barrel support portion of the syringe pump in Figure 1. Figure 5 is a cross-sectional view showing the barrel support portion as seen in the direction of the arrow on the VV line in Figure 4.

[0025] Referring to Figures 1 to 5, the syringe pump 100 has a barrel support portion 50. The barrel support portion 50 supports the barrel 20 of the syringe 10 which is attached to the syringe pump 100. The barrel support portion 50 is integrally molded from resin.

[0026] The barrel support section 50 has a barrel receiving section 51 and a barrel positioning section 52. The barrel 20 is placed on the barrel receiving section 51. The cylindrical section 23 of the barrel 20 is placed on the barrel receiving section 51.

[0027] The barrel receiving portion 51 has a first surface 61. The first surface 61 faces the cylindrical portion 23 of the barrel 20. The first surface 61 is in contact with the outer circumferential surface 26 of the cylindrical portion 23. The first surface 61 is a concave surface that is recessed in the Y-axis direction corresponding to the mounting direction of the syringe 10 to the syringe pump 100 and extends in the Z-axis direction corresponding to the axial direction of the syringe 10. The first surface 61 is a curved surface that extends in the circumferential direction with respect to a central axis 200 parallel to the Z-axis direction. The first surface 61 extends within an angle range smaller than 180° with respect to the central axis 200.

[0028] Furthermore, the first surface 61 is not limited to the shape described above. For example, when viewed in the Z-axis direction, it may have an arc shape in which the radius of curvature is relatively small at the bottom in the Y-axis direction and relatively large at both ends in the X-axis direction.

[0029] The barrel positioning section 52 positions the barrel 20 in the Z-axis direction. The barrel positioning section 52 has a second surface 62. The second surface 62 extends in a direction perpendicular to the first surface 61. The second surface 62 consists of a plane perpendicular to the Z-axis (X-axis-Y-axis plane). The second surface 62 forms a corner 71 with the first surface 61. The second surface 62 is connected to the other end of the first surface 61 in the Z-axis direction via the corner 71.

[0030] The barrel positioning section 52 further has a third surface 63. The third surface 63 is a plane (X-axis-Y-axis plane) perpendicular to the Z-axis. The third surface 63 faces the second surface 62 with a gap in the Z-axis direction. A groove 53 is provided between the second surface 62 and the third surface 63.

[0031] The flange portion 21 is inserted into the groove 53. The barrel 20 is positioned in the Z-axis direction by the end face 27 of the flange portion 21 contacting the second surface 62.

[0032] Referring to Figure 1, a read / write unit 160 is provided inside the barrel receiving unit 51. The read / write unit 160 is capable of transmitting electromagnetic waves to the response unit 40 of the barrel 20 placed on the barrel receiving unit 51, and is also capable of receiving data transmitted from the response unit 40 in response to the transmitted electromagnetic waves.

[0033] The syringe pump 100 further includes a drive unit 120. The drive unit 120 drives the plunger rod 30.

[0034] The drive unit 120 has a pressing surface 121 and a movable claw portion 122. The pressing surface 121 presses the rod flange portion 31 in the Z-axis direction. The movable claw portion 122 holds the rod flange portion 31 by clamping it with the pressing surface 121. The movable claw portion 122 is biased in a direction approaching the pressing surface 121 by a biasing mechanism such as a spring. The drive unit 120 holds the plunger rod 30 so that it can move. The plunger rod 30 driven by the drive unit 120 moves within the barrel 20 in the axial direction of the barrel 20 toward the injection port 22. As a result, the liquid inside the barrel 20 is discharged from the barrel 20 and injected into the tube through the injection port 22.

[0035] The syringe pump 100 further includes a barrel holding portion 112. The barrel holding portion 112 holds the barrel 20 by pressing the cylindrical portion 23 of the barrel 20 toward the first surface 61.

[0036] The barrel holding portion 112 is positioned opposite the barrel receiving portion 51 in the Y-axis direction. When viewed from above, the barrel holding portion 112 is positioned to overlap with the first surface 61. The barrel holding portion 112 is positioned away from the second surface 62 in the Z-axis direction.

[0037] The barrel holder 112 is provided to be rotatable about an axis extending in the Z-axis direction. By rotating toward the barrel receiving portion 51, the barrel holder 112 presses the cylindrical portion 23 of the barrel 20, which is placed on the barrel receiving portion 51, toward the first surface 61. The barrel 20 is held in place by the cylindrical portion 23 being sandwiched between the barrel holder 112 and the barrel receiving portion 51.

[0038] Figure 6 shows the state in which the syringe is attached to the syringe pump as seen in the direction indicated by arrow VI in Figure 3. Figure 7 is a cross-sectional view showing the state in which the syringe is attached as seen in the direction of the arrow along the line VII-VII in Figure 6. Figure 7 shows the cross-sectional shape of the barrel support portion 50 and the barrel 20 when cut by a plane containing the central axis 200. Figure 8 is a cross-sectional view showing the corner of the barrel support portion in Figure 7.

[0039] Although Figure 6 shows a barrel 20 in which the radius of curvature of the outer surface 26 of the cylindrical portion 23 is equal to the radius of curvature of the first surface 61, the invention is not limited to this, and a barrel in which the radius of curvature of the outer surface 26 of the cylindrical portion 23 is smaller than the radius of curvature of the first surface 61 may be attached to the syringe pump 100.

[0040] Referring to Figures 6 to 8, a chamfered shape is provided at the corner 71. As shown in Figure 8, the chamfered shape is provided so as not to protrude from the virtual curved surface 230 that connects the first surface 61 and the second surface 62 with a radius of curvature a = 2.3 mm.

[0041] In this embodiment, the corner portion 71 is provided with an R-chamfer with a radius of curvature b (b≧a=2.3mm). The radius of curvature b of the R-chamfer may be 2.5mm or more (b≧2.5mm) or 3.0mm or more (b≧3.0mm).

[0042] When the barrel support portion 50 is viewed in the axial direction of the cylindrical portion 23 of the barrel 20, the corner portion 71 extends in an arc shape around the central axis 200. The corner portion 71 extends within an angle range smaller than 180° around the central axis 200. The chamfered shape is continuously provided between one end and the other end of the corner portion 71 that extends in an arc shape around the central axis 200 (the range shown by arrow 260 in Figure 6).

[0043] The size of the chamfer shape provided on the corner portion 71 may vary in the circumferential direction with respect to the central axis 200. For example, the radius of curvature of the R chamfer provided on the corner portion 71 may be relatively smaller at the bottom of the corner portion 71 in the Y-axis direction and relatively larger at one end and the other end of the arc-shaped corner portion 71.

[0044] The chamfered shape is provided so as not to overlap with the barrel holding portion 112 when viewed from the front of the first surface 61 (when viewed in the Y-axis direction). The barrel holding portion 112 is provided in the Z-axis direction at a position closer to one end of the cylindrical portion 23 than the chamfered shape provided at the corner portion 71.

[0045] Figure 9 is a cross-sectional view showing a modified example of the corner portion of the barrel support in Figure 7. Referring to Figure 9, in this modified example, the corner portion 71 is provided with a chamfer with a chamfer length c (c≧a=2.3mm). The angle of the chamfer is 45°. The chamfer length c of the chamfer may be 2.5mm or more (c≧2.5mm) or 3.0mm or more (c≧3.0mm). The angle of the chamfer is not limited to 45°, and may be, for example, a combination of 30° and 60°.

[0046] As shown in Figure 2, in the barrel 20, the corner 28 where the outer circumferential surface 26 of the cylindrical portion 23 and the end face 27 of the flange portion 21 meet is a curved surface. Therefore, when attempting to attach the syringe 10 to the syringe pump 100, the corner 28 of the barrel 20 interferes with the corner formed by the first surface 61 and the second surface 62 of the barrel support portion 50, raising concerns that the rear end of the barrel 20 may lift off the first surface 61. In this case, the attachment of the syringe 10 to the syringe pump 100 becomes unstable, and problems arise in which proper dispensing of the drug solution is hindered, due to reasons such as the direction of movement of the plunger rod 30 by the drive unit 120 not matching the axial direction of the cylindrical portion 23 of the barrel 20. In addition, an excessive gap is created between the first surface 61 and the response unit 40, which negatively affects data communication between the response unit 40 and the read / write unit 160.

[0047] As shown in Figures 7 and 8, in this embodiment, the corner 71 formed by the first surface 61 and the second surface 62 of the barrel support portion 50 is provided with a chamfered shape so as not to protrude from the virtual curved surface 230 that connects the first surface 61 and the second surface 62 with a radius of curvature a = 2.3 mm. This configuration prevents the corner 71 from interfering with the corner 28 of the barrel 20, and allows the barrel 20 to be placed on the barrel support portion 51 in an appropriate position. As a result, the syringe 10 can be stably attached to the syringe pump 100, and the above-mentioned problem can be resolved.

[0048] Furthermore, in this embodiment, the chamfered shape is continuously provided between one end and the other end of the corner portion 71 that extends in an arc shape around the central axis 200. With this configuration, regardless of the size of the barrel 20, it is possible to reliably prevent the corner portion 28 of the barrel 20 from interfering with the corner portion 71 of the barrel support portion 50.

[0049] Furthermore, in this embodiment, the chamfered shape is provided so as not to overlap with the barrel holding portion 112 when viewed from the front of the first surface 61. With this configuration, the syringe 10 can be attached to the syringe pump 100 even more stably by bringing the cylindrical portion 23 of the barrel 20 into contact with the first surface 61 directly below the barrel holding portion 112.

[0050] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of symbols]

[0051] 10 Syringe, 20 Barrel, 21 Flange, 22 Injection port, 23 Cylindrical section, 26 Outer surface, 27 End face, 28 Corner, 30 Plunger rod, 31 Rod flange, 32 Gasket, 40 Response section, 50 Barrel support section, 51 Barrel receiving section, 52 Barrel positioning section, 53 Groove section, 61 First surface, 62 Second surface, 63 Third surface, 71 Corner, 100 Syringe pump, 112 Barrel holding section, 120 Drive section, 121 Pressing surface, 122 Movable claw section, 160 Writing section, 200 Central axis, 230 Virtual curved surface.

Claims

1. A barrel receiving portion having a first surface facing the cylindrical portion of the barrel, on which the barrel is placed, It comprises a barrel positioning portion that extends in a direction perpendicular to the first surface, forms an angle with the first surface, has a second surface facing the flange portion of the barrel, and positions the barrel in the axial direction of its cylindrical portion, A syringe pump is provided with a chamfered shape at the corner so as not to protrude from the virtual curved surface that connects the first and second surfaces with a radius of curvature of 2.3 mm.

2. When viewed in the axial direction of the cylindrical portion of the barrel placed on the barrel receiving portion, the corner portion extends in an arc shape. The syringe pump according to claim 1, wherein the chamfered shape is provided continuously between one end and the other end of the arc-shaped corner.

3. The barrel further comprises a barrel holding portion that presses the cylindrical portion of the barrel toward the first surface and holds the barrel, The syringe pump according to claim 1 or 2, wherein the chamfered shape is provided so as not to overlap with the barrel holding portion in a front view of the first surface.

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