Injection Systems, Syringes, and Gaskets

Abstract

To downsize an injection head.SOLUTION: An injection system 1 includes: a gasket 100 equipped with a plurality of engaging pawls 122 and a tip part 140 having an elliptic cross-sectional shape whose length in the height direction is larger than the length in the width direction orthogonal to the height direction; a ram 110 that engages with the gasket 100; a cylinder 91 into which the gasket 100 is inserted; and an injection device 2 configured to advance the ram 110 for injecting a medicinal solution in the cylinder 91. Each of the plurality of engaging pawls 122 is displaced between a spread position and a narrowed position, and includes an inner surface S that defines a hole H whose inlet has an enlarged diameter, and inclines in a direction away from a perpendicular P passing through the center of the hole H. In the plurality of engaging pawls 122, two of the engaging pawls 122 aligned in the height direction are the same in shape and size, and two of the engaging pawls 122 aligned in the width direction are the same in shape and size.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to an injection system equipped with a syringe filled with a liquid medicine. [Background technology]

[0002] Conventionally, as a ram and a gasket used in a syringe for injecting a liquid medicine, for example, Patent Document 1 describes a plunger having an expandable and contractable portion, and a syringe having a first inner diameter and a second inner diameter smaller than the first inner diameter. The end portion of the plunger shaft is inserted into the space of the plunger. Then, when the plunger advances inside the syringe until it reaches the second inner diameter, the expandable and contractible portion contracts. This causes the tab of the plunger (gasket) to engage with the groove of the plunger shaft (ram). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-111185 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the injection device is not sufficiently miniaturized. [Means for solving the problem]

[0005] In order to solve the above problem, an injection system as an example of the present invention comprises a gasket having a plurality of engaging claws and a tip portion having an elliptical cross-sectional shape whose height direction length is longer than its width direction length perpendicular to the height direction, a ram that engages with the gasket, a cylinder into which the gasket is inserted, and an injection device configured to advance the ram and inject the medicinal solution in the cylinder, wherein the plurality of engaging claws are displaceable between a widened position and a narrowed position, define a hole with an enlarged entrance, and include an inner surface that slopes away from a perpendicular line passing through the center of the hole, and among the plurality of engaging claws, two engaging claws aligned in the height direction have the same shape and size, and two engaging claws aligned in the width direction have the same shape and size. Another example of a syringe according to the present invention comprises a gasket having a plurality of engaging claws and a tip portion having an elliptical cross-sectional shape whose height direction length is longer than its width direction length perpendicular to the height direction, and a cylinder into which the gasket is inserted, wherein the plurality of engaging claws are displaceable between a widened position and a narrowed position, define a hole with an enlarged entrance, and include an inner surface that slopes away from a perpendicular line passing through the center of the hole, and among the plurality of engaging claws, two engaging claws aligned in the height direction have the same shape and size, and two engaging claws aligned in the width direction have the same shape and size. Furthermore, another example of a gasket of the present invention comprises a plurality of engaging claws and a tip portion having an elliptical cross-sectional shape whose height direction length is longer than its width direction length perpendicular to the height direction, the plurality of engaging claws are displaceable between widened and narrowed positions, define a hole with an enlarged entrance, and include an inner surface that slopes away from a perpendicular line passing through the center of the hole, and among the plurality of engaging claws, two engaging claws aligned in the height direction have the same shape and size, and two engaging claws aligned in the width direction have the same shape and size.

[0006] Further features of the invention will become apparent from the following description of embodiments thereof, given by way of example with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is a schematic perspective view of an injection head. [Diagram 2] FIG. 2 is a schematic perspective view of an injection head. [Diagram 3] FIG. 2 is a schematic perspective view of an adapter. [Figure 4] FIG. 2 is a schematic exploded perspective view of the syringe. [Diagram 5] FIG. 2 is a schematic rear view of the syringe. [Figure 6] 1 is a schematic cross-sectional view of a gasket according to a first embodiment. [Figure 7] FIG. 4 is a schematic perspective view of the gasket as viewed from the rear. [Figure 8] FIG. 13 is a schematic cross-sectional view illustrating the connection of the ram and the gasket. [Figure 9] FIG. 13 is a schematic cross-sectional view illustrating the connection of the ram and the gasket. [Figure 10] FIG. 6 is a schematic cross-sectional view of a gasket according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, exemplary embodiments for carrying out the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of components described in the following embodiments are arbitrary and can be changed according to the configuration of the device to which the present invention is applied or various conditions. Furthermore, unless otherwise specified, the scope of the present invention is not limited to the embodiments specifically described below. In the following description, the front side ("front") corresponds to the tip side of the syringe, and the opposite side corresponds to the rear side ("rear").

[0009] [First embodiment] 1 and 2 are schematic perspective views of an injection system 1 for injecting a medicinal liquid, with Fig. 1 showing the injection system 1 before a syringe 90 is mounted, and Fig. 2 showing the injection system 1 after the syringe 90 is mounted. As shown in Fig. 1, the injection system 1 includes an injection head 2, which is an example of an injection device. The injection head 2 is configured to advance a ram 110, and injects the medicinal liquid in a cylinder 91 of the syringe 90.

[0010] The injection system 1 is connected to an imaging device (not shown) by wire or wirelessly. When injecting a medicinal liquid and taking an image, various data are transmitted and received between the imaging device and the injection system 1. Examples of such imaging devices include an MRI (Magnetic Resonance Imaging) device, a CT (Computed Tomography) device, an angio imaging device, a PET (Positron Emission Tomography) device, a SPECT (Single Photon Emission Computed Tomography) device, a CT angio device, an MR angio device, an ultrasound diagnostic device, and a blood vessel imaging device.

[0011] The injection head 2 of the injection system 1 includes a pressing unit 4 that presses a gasket 100 (FIG. 4) inserted into a syringe 90. The pressing unit 4 is controlled by a control unit (not shown) to press the gasket 100 in the syringe 90 and move forward in order to deliver the medicinal liquid from the syringe 90. The pressing unit 4 also includes a drive mechanism (not shown) and a ram 110 connected to the drive mechanism. Specifically, the control unit controls the motor in the injection head 2 so that the ram 110 moves forward when the motor rotates forward and moves backward when the motor rotates reversely. The injection head 2 may also include a reading unit that reads a data carrier such as an RFID or a barcode provided on the syringe 90.

[0012] The drive mechanism of the pressing unit 4 includes a transmission mechanism connected to the shaft of the motor, a ball screw shaft connected to the transmission mechanism, a ball screw nut attached to the ball screw shaft, and an actuator connected to the ball screw nut. The transmission mechanism has a pinion gear connected to the shaft and a screw gear connected to the ball screw shaft. The transmission mechanism transmits rotation from the motor to the ball screw shaft. Therefore, the rotation of the motor shaft is transmitted to the ball screw shaft via the pinion gear and the screw gear. As a result, the ball screw shaft rotates according to the transmitted rotation. The ball screw nut slides forward or backward with the rotation of the ball screw shaft. The ram 110 of the pressing unit 4 moves forward or backward with the sliding of the ball screw nut.

[0013] Injection system 1 also includes a console (not shown) having a touch panel as a display unit that displays the injection status of the liquid medicine, and a control device (not shown) having a control unit and a power source. This console and injection head 2 can be connected to each other by wire or wirelessly. Furthermore, a remote control device such as a hand switch may be connected to the console by wire or wirelessly. The remote control device can also be used to start or stop liquid medicine injection. Note that injection head 2 and the control device can be configured integrally with a caster stand (not shown). Alternatively, injection head 2 and the control device may be separate entities and mounted on the caster stand.

[0014] The control device stores data on the operation pattern (injection protocol) and data on the medicinal liquid in advance. When injecting a medicinal liquid into a patient, an operator operates the touch panel of the console to input the patient's physical data, such as the injection speed, injection amount, injection time, weight, height, body surface area, heart rate, and cardiac output, as well as data on the type of medicinal liquid. The control device then calculates optimal injection conditions based on the input data and the pre-stored data. The control device then determines the amount of medicinal liquid to be injected into the patient and the injection protocol based on the calculated injection conditions.

[0015] Furthermore, once the control device has determined the amount of medicinal liquid and the injection protocol, it causes the control device to display predetermined data or graphs on the touch panel of the console. This allows the operator to check the displayed data or graphs. Data on the operation pattern (injection protocol) and data on the medicinal liquid can also be input from an external storage medium. Alternatively, a head display may be provided on injection head 2, and the control device may cause the head display to display predetermined data or graphs. If this head display is a touch panel, the operator can set the injection conditions, etc. from the head display. Furthermore, the head display may be built into injection head 2, or may be attached to the side of injection head 2.

[0016] When injecting a liquid drug, the operator turns on the power of injection head 2 and mounts syringe 90 on injection head 2 as shown in FIG. 2. The operator then presses the injection button displayed on the touch panel. When the injection button is pressed, the control unit sends a forward rotation signal to the motor as a drive voltage. In response to this forward rotation signal, the motor shaft rotates forward, and ram 110 of pressing unit 4 moves forward. Thereafter, when injection is completed and syringe 90 is to be removed, the control unit sends a reverse rotation signal to the motor as a drive voltage to move ram 110 backward. In response to this reverse rotation signal, the motor shaft rotates reversely, and ram 110 moves backward.

[0017] If the injection head 2 is provided with an operation panel, the operator can also press an injection button on the operation panel. Additionally, the operator can also start injection by pressing a button on a hand switch. Alternatively, the operator can turn on the power of the injection head 2 after mounting the syringe 90.

[0018] 3 is a schematic perspective view showing an adapter 8 for mounting a syringe 90 on the injection head 2. As shown in FIG. 3, the adapter 8 has two grooves having a substantially U-shaped cross section, and can be removably attached to a holder 7 of the injection head 2. As an example, the holder 7 has a receiving portion 71 having a shape complementary to the outer shape of the adapter 8. The operator then attaches the adapter 8 to the holder 7 so that the adapter 8 is inserted into the receiving portion 71. The adapter 8 may be configured integrally with the holder 7.

[0019] Moreover, the holder 7 is formed with a step portion 72 that protrudes inward. This defines a groove between the adapter 8 and the holder 7 that constitutes a gap for receiving the flange 92 (FIG. 4) of the syringe 90. The holder 7 also has two holding portions 73 having a substantially U-shaped cross section so as to hold the rear end of the syringe 90. That is, the syringe 90 has a substantially elliptical cross section, and the holding portions 73 of the holder 7 have a shape complementary to the outer shape of the syringe 90. This reduces the width of the syringe 90 in the horizontal direction perpendicular to the up-down direction of the syringe 90, and accordingly reduces the width of the holding portions 73 in the horizontal direction. As a result, the width of the injection head 2 in the horizontal direction can be reduced, thereby reducing the size of the injection head 2. That is, compared to when the syringe 90 has a circular cross section, the width of the syringe 90 is reduced, and therefore the injection head 2 can be made smaller. This small injection head 2 allows the injection system 1 to be installed in a CT examination room with a smaller space. The effect of miniaturization is particularly great in an injection head 2 capable of mounting two syringes 90. Alternatively, holder 7 may be configured so as to be capable of mounting one or three or more syringes 90. In this case, holding portions 73 are formed in a number corresponding to the number of mountable syringes 90.

[0020] Further, a pair of engagement parts 83 are formed on the front surface of the adapter 8 so as to sandwich the holding part 73. As an example, these engagement parts 83 have a straight part extending downward and a protruding part formed at the lower end of the straight part. The engagement parts 83 have elasticity and are deformed by being pushed by a protrusion 95 (FIG. 4) formed on the rear surface of the cylinder 91. Specifically, the engagement parts 83 are displaced backward when pushed by the protrusion 95. Thereafter, the engagement parts 83 are displaced forward by their own elasticity and return to their original position. As a result, the protruding parts of the engagement parts 83 climb over the protrusion 95 and are positioned above it. As a result, the engagement parts 83 and the protrusion 95 come into contact with each other, and the upward movement of the syringe 90 is restricted by the engagement parts 83.

[0021] Furthermore, when the protrusion 95 passes over the engaging portion 83, the operator can feel a click. This allows the operator to recognize that the syringe 90 is loaded in the correct position. Alternatively, only one engaging portion 83 may be formed on one side of the holding portion 73, or a total of three or more engaging portions 83 may be formed on both sides of the holding portion 73. Note that the engaging portion 83 may have other configurations as long as it has a protruding portion configured to be able to advance and retreat. For example, the engaging portion 83 may be configured of an elastic body protruding forward and a cover member covering the elastic body.

[0022] Further, the adapter 8 is formed with a hole 82 that allows liquid such as a drug solution to escape to the outside of the injection head 2. Specifically, if liquid is spilled onto the adapter 8, the liquid can escape to the outside via this hole 82. For this reason, an opening (not shown) corresponding to the hole 82 is also formed in the holder 7. The adapter 8 may be configured so that a syringe 90 can be mounted thereon. In this case, a groove for receiving a flange 92 and a holding portion for holding the syringe 90 are formed in the adapter 8. Furthermore, the adapter 8 may be omitted, and a groove for receiving the flange 92 may be formed in the holder 7.

[0023] 4 is a schematic exploded perspective view of the syringe 90, showing the syringe 90 as viewed from above the front side. As shown in FIG. 4, the syringe 90 includes a cylinder 91 having a tip portion 93 and a flange 92 that is inserted between the adapter 8 and the holder 7. The syringe 90 also includes a gasket 100 that is slidable within the cylinder 91. The gasket 100 is inserted into the cylinder 91, and the outer surface of the inserted gasket 100 abuts against the inner surface of the cylinder 91. The gasket 100 also engages with a front end portion 111 of a ram 110, and slides within the cylinder 91 by the ram 110.

[0024] The gasket 100 is provided with a seal member 140 as a tip portion having an elliptical cross-sectional shape. In the cross section of this seal member 140, the length in the height direction is longer than the length in the width direction perpendicular to the height direction. The gasket 100 is also provided with a plunger 120 having a plurality of divided engaging claws 122, and the tip of the plunger 120 is inserted into the seal member 140. The plunger 120 is made of an elastic resin such as POM (polyacetal resin) and can be manufactured by molding. The seal member 140 is made of butyl rubber and can be manufactured by molding.

[0025] The gasket 100 is engaged with the ram 110 by the engagement of the engagement claw 122 with the front end 111 of the ram 110. When the motor rotates forward with the engagement claw 122 connected to the ram 110, the pressing part 4 pushes the ram 110 forward. When the ram 110 and the gasket 100 move forward, the medicinal liquid in the cylinder 91 is pushed out through the tip 93. As a result, the medicinal liquid is injected into the patient's body through an extension tube connected to the tip 93. After the injection of the medicinal liquid, when the motor rotates in the reverse direction, the pressing part 4 pulls the ram 110 in the backward direction, and the gasket 100 moves backward. The engagement claw 122 may have a groove into which an O-ring is fitted. In this case, the spread of the engagement claw 122 can be restricted by fitting the O-ring. The tip 93 can be connected to the extension tube through a lock connector, a luer lock, a push-in connector, or the like.

[0026] The cylinder 91 into which the gasket 100 is inserted has a cross-sectional shape complementary to that of the gasket 100. That is, the cylinder 91 has a substantially elliptical cross-sectional shape, and the length in the height direction in the cross-section is longer than the length in the width direction perpendicular to the height direction. Therefore, when the rear end of the syringe 90 is held by the holding part 73 of the holder 7, both side surfaces of the rear end abut against the inner surface of the holding part 73. This prevents the syringe 90 from rotating relative to the holder 7. For example, when a liquid medicine is injected, the gasket 100 is pushed into the cylinder 91 by the ram 110 that moves forward while rotating. At this time, a rotational force is also transmitted to the syringe 90 via the gasket 100. However, since both side surfaces of the rear end abut against the inner surface of the holding part 73, the rotation of the syringe 90 is prevented.

[0027] The ram 110 is made of, for example, stainless steel or aluminum, and can be manufactured by welding a solid, substantially cylindrical front end 111 to a hollow pipe. Alternatively, the ram 110 may be manufactured by screwing the solid front end 111 into a hollow pipe. Furthermore, the front end 111 may be manufactured using a material other than stainless steel or aluminum, for example, a material harder than the gasket 100. The front end 111 is formed with an annular engagement groove 112 extending in the circumferential direction. Then, the gasket 100 and the ram 110 are engaged with each other by inserting a protrusion 124 (FIG. 6) of an engagement claw 122 into the engagement groove 112.

[0028] FIG. 5 is a schematic rear view of the syringe 90 with the gasket 100 inserted. As shown in FIG. 5, the syringe 90 has a protrusion 95, and the protrusions 95 are formed on the cylinder 91, two on each side, for a total of four. The protrusions 95 protrude laterally from an annular portion 96 protruding rearward from the flange 92. That is, the flange 92 is formed with a substantially ring-shaped annular portion 96, and the protrusions 95 are formed so as to protrude from the annular portion 96. When the syringe 90 is mounted, the protrusions 95 climb over the engagement portion 83 of the adapter 8. After the syringe 90 is mounted, the engagement portion 83 abuts against the protrusion 95, so that the upward movement of the syringe 90 is restricted. Alternatively, the protrusions 95 may be formed on only one side of the hole H formed in the center of the gasket 100, or on both sides of the hole H, for a total of three or more protrusions.

[0029] The flange 92 has a substantially elliptical outer shape. However, the length L1 in the height direction (vertical direction in FIG. 5) of the first portion 97 located on the lower side in FIG. 5 is longer than the length L2 in the height direction of the second portion 98 located on the upper side. That is, the length L1 of the first portion 97 extending upward from the cylinder 91 in the height direction is longer than the length L2 of the second portion 98 extending downward. This allows the operator to visually recognize the correct orientation and up-down direction of the syringe 90. In addition, by lengthening the first portion 97, the contact area between the holder 7 or the adapter 8 and the flange 92 is increased. This allows the syringe 90 to be stably held, and therefore allows it to withstand a higher injection pressure. Furthermore, the first portion 97 of the flange 92 is provided with an arrow 99 indicating the insertion direction.

[0030] Alternatively, the second part 98 extending upward may be longer than the first part 97 extending downward. Even in this case, the operator can visually recognize the correct orientation and insertion direction of the syringe 90. Furthermore, if the second part 98 extending upward is long, it is possible to prevent the second part 98 from being erroneously inserted downward when inserting the flange 92 into the groove between the holder 7 and the adapter 8. That is, since the depth of the groove corresponds to the length of the shorter first part 97, if the second part 98 is inserted in the wrong orientation, the second part 98 will hit the bottom of the groove before the protrusion 95 overcomes the engagement part 83. Therefore, the operator cannot feel a click and can recognize that the orientation is incorrect. This allows the operator to correct the orientation of the syringe 90 and mount it.

[0031] In the gasket 100, two engaging claws 122 arranged in one direction, the height direction, have the same shape and size. Also, two engaging claws 122 arranged in the other direction, the width direction, perpendicular to the height direction, have the same shape and size. This allows the displacement amount of the engaging claws 122 to be approximately the same in the height direction and the width direction perpendicular to the height direction. In other words, since the gasket 100 has a substantially elliptical outer shape, if the shapes and sizes of the multiple engaging claws 122 are made the same, the displacement amount from the start of the displacement of the engaging claws 122 will be different in the height direction and the width direction. Therefore, the shapes and sizes of the engaging claws 122 arranged in the height direction and the engaging claws 122 arranged in the width direction are made different so that the displacement amounts of all the engaging claws 122 are approximately the same. That is, in the gasket 100 having a substantially elliptical outer shape, the two engaging claws 122 arranged in the height direction are both formed to have the same size. In addition, in the gasket 100, the two engaging claws 122 arranged in the width direction are both formed to have the same size. In addition, in the central portion surrounded by the four engaging claws 122, a substantially circular hole H into which the front end portion 111 of the ram 110 is inserted is formed. Therefore, the height of the engaging claws 122 arranged in the height direction is longer than the height of the engaging claws 122 arranged in the width direction. In addition, a substantially fan-shaped recess 129 is formed in each engaging claw 122. Furthermore, a protrusion 124 that engages with the engaging groove 112 of the ram 110 is formed on the periphery of the hole H. Then, when the ram 110 is inserted until the end face of the front end portion 111 abuts against the bottom of the hole H, the engaging groove 112 and the protrusion 124 face each other.

[0032] 6 is a schematic cross-sectional view of the gasket 100 along the front-rear direction and the height direction. The plunger 120 has a substantially disk-shaped insertion portion 121, and a plurality of intersecting ribs (not shown) are formed in the insertion portion 121. An annular groove 125 is formed between the insertion portion 121 and the engagement claw 122. The seal member 140 has an annular protrusion 141 formed on its outer periphery. The annular protrusion 141 comes into contact with the inner surface of the cylinder 91 to seal the cylinder 91. Although three annular protrusions 141 are formed in FIG. 2, two, one, or four or more annular protrusions may be formed. A space for accommodating the insertion portion 121 is formed in the seal member 140, and the rear end of the seal member 140 protrudes toward the space.

[0033] A generally sector-shaped recess 129 is formed in the engaging claw 122 of the plunger 120. The recess 129 allows the engaging claw 122 to be made thinner. Therefore, the engaging claw 122 is more easily deformed than the insertion portion 121. Also, the portion in which the annular groove 125 is formed is thinner than the portion in which the engaging claw 122 is formed and the insertion portion 121. As a result, the annular groove 125 becomes the starting point for deformation of the engaging claw 122. The bottom of the annular groove 125 has a generally semicircular cross-section. Alternatively, the bottom of the annular groove 125 may have a generally trapezoidal or triangular cross-section that narrows toward the inside.

[0034] The hole H of the plunger 120 narrows toward the bottom, and when the ram 110 is inserted into the hole H, the end face of the front end 111 abuts against the bottom of the hole H. When the end face of the front end 111 abuts against the bottom of the hole H, a gap is generated between the outer surface of the front end 111 and the inner surface S of the hole H. In other words, the inner surface S of the hole H is inclined toward the center of the bottom. Therefore, the front end 111 inserted into the hole H is guided so as to slide on the inner surface S inclined toward the center of the bottom. This allows the front end 111 to be aligned with the center of the hole H.

[0035] FIG. 7 is a schematic perspective view of the gasket 100 as seen from the rear. As shown in FIG. 7, the suction member 120 of the gasket 100 has a plurality of engagement claws 122, for example, four engagement claws 122, each having a substantially fan-shaped shape. Alternatively, the suction member 120 may have two, three, or five or more engagement claws 122. In addition, a gap is formed between adjacent engagement claws 122, and when the gasket 100 advances in the cylinder 91, the adjacent engagement claws 122 are displaced so as to approach each other. Since the gaps all have the same length and width, it is possible to suppress the position of each engagement claw 122 relative to the ram 110 from fluctuating during displacement. In other words, as the gasket 100 advances, the engagement claws 122 are displaced so as to approach each other by the same distance.

[0036] Each of the engaging claws 122 has a projection 124 that engages with the engaging groove 112 of the ram 110. This projection 124 projects toward the center of the suction cup 120. The tip of the projection 124 is rounded so as to facilitate insertion into the engaging groove 112. Note that in FIG. 7, only one projection 124 is indicated by a reference symbol. However, the projection 124 is formed on all of the four engaging claws 122.

[0037] Furthermore, an annular groove 125 is formed between the insertion portion 121 and the engaging claw 122. The engaging claw 122 is connected to the insertion portion 121 at the portion where this annular groove 125 is formed. In order to facilitate the displacement (deformation) of the engaging claw 122, the portion where the annular groove 125 is formed is thinner than the portion where the protrusion 124 is formed. Furthermore, the suction nozzle 120 is formed with a hole H surrounded by the protrusion 124, and the ram 110 is inserted into the hole H so as to engage with the engaging claw 122.

[0038] [Connection of Ram 110 and Gasket 100] The connection between the ram 110 and the gasket 100 will be described with reference to Figs. 8 and 9. Fig. 8 is a schematic cross-sectional view of the syringe 90 before the ram 110 is inserted into the hole H of the plunger 120. Fig. 9 is a schematic cross-sectional view of the syringe 90 in a state in which the ram 110 has advanced the gasket 100. Figs. 8 and 9 also show a cross section along the longitudinal direction passing through the central axis of the cylinder 91. For ease of explanation, Figs. 8 and 9 show the plunger 120 and the seal member 140 as a single body. Figs. 8 and 9 also show only the upper half of the ram 110 and the gasket 100 in the height direction. The lower part of the ram 110 and the gasket 100 in the height direction has substantially the same shape as the upper part, except for the flange 92.

[0039] As shown in Fig. 8, the gasket 100 has a hole H with an enlarged entrance. That is, the entrance of the hole H through which the ram 110 is inserted has a larger inner diameter than the bottom against which the end face of the front end 111 of the ram 110 presses. The gasket 100 also has an engagement pawl 122 that is displaceable between an enlarged position (Fig. 8) and a narrowed position (Fig. 9). The engagement pawl 122 includes an inner surface S that defines the hole H and slopes away from a perpendicular line P that passes through the center of the hole H (bottom).

[0040] The engaging claw 122 has a protrusion 128 protruding in a direction away from the perpendicular line P passing through the center of the hole H. In addition, an expanded diameter portion 94 for receiving the protrusion 128 is formed at the rear end of the cylinder 91. That is, the inner diameter of the rear end of the cylinder 91 is larger than the inner diameter of the other parts. When the gasket 100 is assembled to the cylinder 91, the protrusion 128 is received in the expanded diameter portion 94, and the entire gasket 100 is accommodated in the cylinder 91. Alternatively, the rear portion of the engaging claw 122 may protrude outward from the cylinder 91. In addition, the engaging claw 122 has a protrusion 124 protruding inwardly of the hole H. The ram 110 has an annular engaging groove 112 that engages with the protrusion 124. The expanded diameter portion 94 may be a stepped step, or may be an inclined surface or a curved surface that narrows toward the center of the cylinder 91.

[0041] 9, when the ram 110 is inserted into the hole H, the end face of the front end 111 abuts against the bottom of the hole H. Then, when the ram 110 pushes the gasket 100, the gasket 100 advances inside the cylinder 91. As the gasket 100 advances, the ridge 128 of the engagement claw 122 abuts against the enlarged diameter portion 94 of the cylinder 91. Then, as the gasket advances and the ridge 128 passes the enlarged diameter portion 94, the engagement claw 122 is displaced toward the perpendicular line P. At this time, the engagement claw 122 deforms with the center of the bottom of the annular groove 125 as the starting point.

[0042] As a result, even if the front end 111 is inserted into the hole H at a position offset from the perpendicular line P, the front end 111 is displaced so that the central axis of the front end 111 is aligned with the perpendicular line P. That is, the front end 111 is pushed by a portion corresponding to the bottom of the annular groove 125 and displaced toward the center of the hole H. This makes it possible to prevent the central axis of the ram 110 from being inclined with respect to the gasket 100. As shown in FIG. 9, when the protrusion 128 passes the enlarged diameter portion 94, the engaging claw 122 narrows. Then, the protrusion 124 of the engaging claw 122 in the narrowed position enters the engaging groove 112, and the protrusion 124 engages with the engaging groove 112. As a result, the gasket 100 is connected to the ram 110. In addition, the annular groove 125 is deformed so as to widen as the engaging claw 122 is displaced.

[0043] Thereafter, when the gasket 100 advances within the cylinder 91, the seal member 140 presses the medicinal liquid within the cylinder 91. This causes the medicinal liquid to be pushed out from the tip 93 and injected into the patient's body via an extension tube or the like. After the medicinal liquid is injected, the ram 110 retreats, and the gasket 100 connected to the ram 110 also retreats. Then, when the ram 110 and the gasket 100 retreat to a position where the protrusion 128 is received in the enlarged diameter portion 94, the engaging claws 122 spread outward and the projection 124 disengages from the engaging groove 112.

[0044] This disengages the projection 124 from the engagement groove 112. That is, when the ram 110 and the gasket 100 are retracted until the engagement claw 122 is displaced to the widened position, the projection 124 comes out of the engagement groove 112. Furthermore, as the engagement claw 122 is displaced, the annular groove 125 narrows to return to its original shape. When the ram 110 is retracted further, the gasket 100 remains in the position shown in FIG. 8 due to the frictional force between the seal member 140 and the cylinder 91. As a result, the ram 110 disengages from the gasket 100 and retracts to the pre-insertion position shown in FIG. 8.

[0045] According to the ram 110 and gasket 100 according to the first embodiment, the engaging claws 122 deform with the center of the bottom of the annular groove 125 as the starting point. Therefore, the multiple engaging claws 122 are evenly displaced toward the perpendicular line P of the intake 120. This makes it possible to prevent the front end 111 from being positioned offset relative to the perpendicular line P when the ram 110 is separated from the gasket 100. Therefore, it is possible to prevent the engaging groove 112 of the front end 111 from getting caught on the protrusion 124.

[0046] Furthermore, with the ram 110 and gasket 100 according to the first embodiment, rattling of the ram 110 relative to the gasket 100 can be suppressed when the gasket 100 and the ram 110 are connected to each other. Furthermore, because the gasket 100 and the ram 110 are directly connected to each other, the distance between the syringe 90 and the pressing unit 4 can be shortened. As a result, the size of the injection head 2 in the injection system 1 can be reduced.

[0047] Furthermore, according to the syringe 90 according to the first embodiment, the size in the width direction can be reduced compared to the case where the syringe 90 has a substantially circular cross-sectional shape. That is, the width of the syringe 90 can be narrowed, or the size of the syringe 90 can be reduced. Then, by increasing the size in the height direction of the syringe 90 so as to have a substantially elliptical cross-sectional shape, a syringe 90 with the same capacity and small size can be formed. As a result, the injection head 2 can be made smaller and lighter. In particular, when an actuator equipped with a rotation transmission mechanism housed in a case is built into the frame of the injection head 2, the injection head 2 can be made smaller synergistically. Furthermore, by increasing the size in the height direction, the contact area with the holding part 73 increases. This allows the syringe 90 to be stably fixed.

[0048] Furthermore, according to the syringe 90 according to the first embodiment, the syringe 90 can be held by the holding portion 73 simply by inserting the syringe 90 into the holding portion 73. This makes it possible to more easily attach the syringe 90 without the need to rotate the syringe 90 to attach it to the injection head 2. Furthermore, since the width of the syringe 90 is small, even an operator with small hands can easily grasp the syringe 90. Furthermore, since both side surfaces in the width direction are flat, the syringe 90 can be prevented from rolling when placed on a flat surface such as a table.

[0049] Furthermore, since the distance and contact area with the holding portion 73 increases in the height direction (depth direction), the drug solution can be stably injected. That is, both side surfaces (inner surfaces) in the width direction of the syringe 90 function as fixed guides that guide the gasket 100. Therefore, when the gasket 100 slides, the gasket 100 or the plunger 120 can be prevented from rotating relative to the cylinder 91 due to the sliding resistance during injection. This prevents distortion of the gasket 100 that causes backflow, and allows the ram 110 to move forward and backward stably. Furthermore, since the flange 92 can be made smaller, the cost of manufacturing the cylinder 91 can be reduced by reducing the amount of material used.

[0050] In addition, since the diameter of the syringe 90 differs in the height direction and width direction, the operator can visually recognize the orientation and attachment / detachment direction of the syringe 90. Also, by marking the scale on the upper surface of the cylinder 91, the portion with the scale is located above the holder 7 or the adapter 8. This makes it easier for the operator to see the scale. Furthermore, if air gets into the cylinder 91, the air will accumulate in the upper space inside the cylinder 91, so that the air will remain at a position farther away from the tip 93 and will be prevented from flowing out to the patient side.

[0051] [Second embodiment] In the first embodiment, the gasket 100 includes a seal member 140 and a plunger 120. On the other hand, the second embodiment differs from the first embodiment in that the gasket 200 includes a plunger 220 and an O-ring 230. The second embodiment will be described below with reference to Fig. 10. In the description of the second embodiment, the differences from the first embodiment will be described, and the components described in the first embodiment will be given the same reference numbers and their description will be omitted. Except as otherwise described, the components given the same reference numbers perform substantially the same operations and functions, and have substantially the same effects.

[0052] 10 is a schematic cross-sectional view of the gasket 200 taken along the front-rear and height directions. The gasket 200 has a plunger 220 with a tip portion having an elliptical cross-sectional shape, and an O-ring 230 fitted into the plunger 220. The O-ring 230 is accommodated in an annular O-ring groove 223 formed on the circumferential surface of the plunger 220. The O-ring 230 comes into contact with the inner surface of the cylinder 91, thereby sealing the cylinder 91. Alternatively, there may be two or more O-rings 230, in which case two or more O-ring grooves 223 are formed.

[0053] Furthermore, the plunger 220 has a plurality of engaging claws 222 and an annular groove 225 formed between the engaging claws 222 and the O-ring groove 223. In order to facilitate displacement of the engaging claws 222, the portion in which the annular groove 225 is formed is thinner than other portions. Each engaging claw 222 is formed with a substantially sector-shaped recess 229. The recess 229 allows the engaging claw 222 to have a thinner wall thickness. This makes it easier for the engaging claws 222 to deform.

[0054] In the central portion surrounded by the engaging claws 222, a hole H having a shape narrowing toward the bottom is formed. When the ram 110 is inserted into this hole H, the end face of the front end 111 of the ram 110 abuts against the bottom of the hole H. Then, in a state in which the end face of the front end 111 abuts against the bottom of the hole H, a gap is generated between the outer surface of the front end 111 and the inner surface S of the hole H. Therefore, the front end 111 inserted into the hole H is guided so as to slide on the inner surface S inclined toward the center of the bottom. This allows the front end 111 to be aligned with the center of the hole H. A gap is formed between the adjacent engaging claws 222, and when the gasket 200 advances in the cylinder 91, each engaging claw 222 is displaced so that the adjacent engaging claws 222 approach each other. All of the gaps between the engaging claws 222 have the same length. This makes it possible to suppress the position of each engaging claw 222 relative to the ram 110 from fluctuating during displacement.

[0055] Each of the engagement claws 222 has a projection 224 that engages with the engagement groove 112 of the ram 110. The tip of the projection 224 is rounded so as to be easily inserted into the engagement groove 112 of the ram 110. The gasket 200 of the second embodiment has an inner surface S that defines a hole H with an enlarged entrance, and an annular groove 225 that serves as a starting point for deformation, similar to the first embodiment. Furthermore, the engagement claws 222 have a protrusion 228 that protrudes outward. When the gasket 200 is assembled to the cylinder 91, the protrusion 228 is received in the enlarged diameter portion 94 of the cylinder 91, and the entire gasket 200 is housed within the cylinder 91.

[0056] When the ram 110 and the gasket 200 are connected, the ram 110 is inserted into the hole H, and the end face of the front end 111 of the ram 110 abuts against the bottom of the hole H. Then, when the ram 110 pushes the gasket 200, the gasket 200 advances inside the cylinder 91. As the gasket 200 advances, the ridge 228 of the engagement claw 222 abuts against the enlarged diameter portion 94. Then, as the gasket 200 advances, the ridge 228 passes the enlarged diameter portion 94, and the engagement claw 222 is displaced toward the perpendicular line P. At this time, the engagement claw 222 deforms with the center of the bottom of the annular groove 225 as the starting point.

[0057] As a result, even if the front end 111 is inserted in the hole H at a position offset from the perpendicular line P, the front end 111 is displaced so that the central axis of the front end 111 is aligned with the perpendicular line P. This makes it possible to prevent the central axis of the front end 111 from being tilted with respect to the gasket 200. When the protrusion 228 passes the enlarged diameter portion 94, the engagement claw 222 narrows. Then, the projection 224 of the engagement claw 222 in the narrowed position enters the engagement groove 112 of the ram 110, and the projection 224 engages with the engagement groove 112. As a result, the gasket 200 is connected to the ram 110. In addition, the annular groove 225 is deformed so as to widen as the engagement claw 222 is displaced.

[0058] Thereafter, when the gasket 200 advances within the cylinder 91, the plunger 220 presses against the liquid medicine within the cylinder 91. This causes the liquid medicine to be pushed out from the tip 93. After the liquid medicine is injected, the ram 110 retreats, and the gasket 200 connected to the ram 110 also retreats. Then, when the ram 110 and the gasket 200 retreat to a position where the ridge 228 is received in the enlarged diameter portion 94, the engaging claws 222 spread outward, and the projections 224 of the displaced engaging claws 222 disengage from the engaging grooves 112.

[0059] Furthermore, as the engaging claw 222 is displaced, the annular groove 225 narrows to return to its original shape. As the ram 110 moves further backward, the gasket 200 remains in the cylinder 91 due to the frictional force between the O-ring 230 and the cylinder 91. As a result, the ram 110 disengages from the gasket 200 and moves back to the position before insertion.

[0060] With such a ram 110 and gasket 200 according to the second embodiment, the engaging claws 222 are also deformed starting from the center of the bottom of the annular groove 225. Therefore, the multiple engaging claws 222 are evenly displaced toward the perpendicular line P of the intake suction member 220. This makes it possible to prevent the front end portion 111 from being positioned offset relative to the perpendicular line P when the ram 110 is separated from the gasket 200. Therefore, it is possible to prevent the engaging groove 112 of the front end portion 111 from getting caught on the protrusion 224.

[0061] Furthermore, with the ram 110 and gasket 200 according to the second embodiment, rattling of the ram 110 relative to the gasket 200 can be suppressed when the gasket 200 and the ram 110 are connected to each other. Furthermore, because the gasket 200 and the ram 110 are directly connected to each other, the distance between the syringe 90 and the pressing portion 4 can be shortened. This allows the size of the injection head 2 in the injection system 1 to be reduced. Furthermore, because the size in the width direction can be reduced, a smaller syringe 90 with the same capacity can be formed. As a result, the injection head 2 can be made smaller and lighter.

[0062] Although the present invention has been described above with reference to each embodiment, the present invention is not limited to the above-mentioned embodiment. The present invention also includes inventions that have been modified without going against the present invention, and inventions equivalent to the present invention. In addition, the above-mentioned embodiments and modifications can be appropriately combined without going against the present invention.

[0063] For example, a notch or hole may be formed in the engagement claws 122, 222. This causes the portion in which the notch or hole is formed to deform, making it easier for the engagement claws 122, 222 to be displaced. The inner surface S of the gasket 100, 200 may be divided into two surfaces with different inclinations. The inner surface S may also form a continuous inclined or curved surface. Furthermore, the gasket 100, 200 may have an egg-shaped outer shape in which the length in the height direction is longer than the length in the width direction perpendicular to the height direction. In this case, the cylinder 91 has a shape complementary to the egg-shaped outer shape.

[0064] The syringe 90 filled with the liquid medicine may be a prefilled syringe. The liquid medicine may be filled into the syringe 90 manually, or may be filled into the syringe 90 by the injection head 2 or a filler. The syringe 90 may be provided with a data carrier such as an RFID or a barcode. The data carrier records information about the filled liquid medicine. The injection system 1 can read the recorded information from the data carrier via the injection head 2 and control the injection amount of the liquid medicine. For example, the control device can calculate the optimal injection amount per body weight based on the read information about the liquid medicine (iodine amount) and display it on the touch panel of the console. When filling the empty syringe 90 with the liquid medicine, the liquid medicine may be sucked from a large-capacity bottle provided with a data carrier. This allows the amount of the liquid medicine in the large-capacity bottle to be monitored and the liquid medicine to be injected multiple times. The information about the liquid medicine recorded in the data carrier of the large-capacity bottle may be read and written to an RFID tag or the like of the empty syringe 90. The read information may be used for setting in the injection head 2.

[0065] Furthermore, a notch may be formed in a part of the outer periphery of flange 92. Specifically, flange 92 may have two arcuate portions that are arc-shaped with respect to the central axis of syringe 90, and two flat portions that are formed between the arcuate portions and face each other. In this case, adapter 8 may be provided with, for example, a locking claw, a protrusion, or a latch as an engagement portion that engages with the notch.

[0066] Furthermore, instead of forming the enlarged diameter portion 94 on the cylinder 91, a skirt portion extending rearward beyond the flange 92 may be formed. The inner surface of this skirt portion is inclined to receive the protrusion 128 of the engagement claw 122 so that the engagement claw 122 is positioned in the expanded position. Therefore, the inner dimension of the skirt portion is set to match the outer dimension of the engagement claw 122 in the expanded state. In other words, the skirt portion has a shape that narrows toward the tip portion 93. As a result, the engagement claw 122 of the gasket 100 inserted inside the skirt portion does not displace to the narrowed position. Or, even if the engagement claw 122 is slightly displaced, the interval between the opposing protrusions 124 can maintain a state in which the ram 110 can be inserted.

[0067] In this case, after the front end 111 of the ram 110 is inserted, the ram 110 pushes the gasket 100, causing the gasket 100 to advance inside the cylinder 91. As the gasket 100 advances, the protrusions 128 of the engaging claws 122 pass through the skirt portion and come into contact with the inner surface of the cylinder 91. As the gasket 100 advances, the engaging claws 122 are displaced toward the center of the hole H of the intake suction member 120 due to a reaction force from the inner surface of the cylinder 91.

[0068] Furthermore, instead of forming the enlarged diameter portion 94 on the cylinder 91, the rear portion of the gasket 100 may protrude outward from the cylinder 91. In this case, when the ram 110 pushes the gasket 100, the gasket 100 advances within the cylinder 91. When the gasket 100 advances, the protrusion 128 of the engagement claw 122 rides over the rear end of the cylinder 91 and comes into contact with the inner surface of the cylinder 91. Then, when the protrusion 128 rides over the rear end of the cylinder 91, the engagement claw 122 is displaced toward the perpendicular line P of the intake suction member 120 due to a reaction force from the inner surface of the cylinder 91.

[0069] A part or all of the above-described embodiments can be described as, but is not limited to, the following supplementary notes.

[0070] [Appendix 1] a gasket having a plurality of engagement claws including an inner surface defining a hole with an enlarged entrance and a protrusion protruding in a direction away from a perpendicular line passing through a center of the hole, the engagement claws being displaceable between an enlarged position and a narrowed position; a ram inserted into the hole so as to engage the pawl; a cylinder into which the gasket is inserted, the cylinder abutting against the protrusion of the engagement claw of the gasket after insertion; an injection device configured to advance the ram and configured to inject a chemical solution in the cylinder; An injection system, wherein the gasket has an annular groove formed therein, which serves as a starting point for deformation of the engagement claw.

[0071] [Appendix 2] The injection system of claim 1, wherein the rear end of the cylinder is formed with an enlarged diameter portion that receives the protrusion.

[0072] This application claims priority from Japanese Patent Application No. 2018-200114, filed on October 24, 2018, the entire contents of which are incorporated herein by reference. [Explanation of symbols]

[0073] 1: injection system, 2: injection device, 91: cylinder, 100: gasket, 110: ram, 200: gasket

Claims

1. A gasket having a plurality of engaging claws; a ram engaging the gasket; a cylinder into which the gasket is inserted; an injection device configured to advance the ram and configured to inject a chemical solution in the cylinder; the plurality of engagement pawls are displaceable between a spread position and a contracted position and include an inner surface defining an insertion portion for the ram; The gasket is formed with a groove that becomes a starting point for deformation of the engagement claw, a portion of the engaging claw is located between the insertion portion and a bottom of the groove in a radial direction of the gasket; An injection system, wherein the groove deforms to widen when the engagement claw is displaced to the narrowed position.

2. The injection system of claim 1 , wherein, among the plurality of engagement claws, two engagement claws aligned in the height direction of the gasket have the same shape and size, and two engagement claws aligned in the width direction of the gasket have the same shape and size.

3. Each of the plurality of engagement claws includes a protrusion protruding in a direction away from a perpendicular line passing through a center of the insertion portion, The injection system according to claim 1 or 2, wherein a rear end of the cylinder is formed with an enlarged diameter portion that receives the protrusion.

4. A gasket having a plurality of engaging claws; a cylinder into which the gasket is inserted; the plurality of engagement pawls are displaceable between a spread position and a contracted position and include an inner surface defining a portion for insertion of a ram; The gasket is formed with a groove that becomes a starting point for deformation of the engagement claw, a portion of the engaging claw is located between the insertion portion and a bottom of the groove in a radial direction of the gasket; The groove is deformed so as to widen when the engaging claw is displaced to the narrowed position.

5. A gasket having a plurality of engaging claws, the plurality of engagement pawls are displaceable between a spread position and a contracted position and include an inner surface defining a portion for insertion of a ram; A groove is formed as a starting point for deformation of the engaging claw, a portion of the engaging claw is located between the insertion portion and a bottom of the groove in a radial direction of the gasket; The groove deforms to widen when the engaging claw is displaced to the narrowed position.

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