Drug injector

Abstract

The present invention provides a drug injector that allows for easy attachment and detachment of the nozzle to the barrel, and that enables the nozzle's position relative to the barrel flange to remain constant at all times. [Solution] The drug injector 1 comprises a barrel 10 into which the drug is filled, a nozzle 20 attached to the barrel, and a plunger 40 that pushes the drug filled in the barrel toward the nozzle. The barrel includes a flange 11, a body 12 continuous with the flange into which the plunger is inserted from the flange side, and a tip 13 continuous with the body on the opposite side of the flange. The body extends from the flange in a first direction. The tip extends from the body in a second direction and communicates with the body and the nozzle. The second direction is different from the first direction and is away from the flange. The nozzle extends from the tip in a second direction and is detachably attached to the tip.

Description

Technical Field

[0001] The present disclosure relates to a drug injector.

Background Art

[0002] Conventionally, as disclosed in Japanese Patent Application Laid-Open No. 2000-107298 (Patent Document 1), a drug injector is known. The drug injector of Patent Document 1 includes a barrel having a nozzle mounting portion at its tip, a plunger having a gasket at its tip, and a nozzle that is detachable from the nozzle mounting portion. The nozzle includes a mounting portion to the barrel and a discharge portion that extends from the mounting portion and is bent at a predetermined angle.

[0003] Specifically, in the drug injector of Patent Document 1, the nozzle mounting portion of the barrel consists of a tip chip that fits into the inner cavity of the nozzle and a female screw provided concentrically outside the tip chip. The female screw engages with a male screw provided at the base end of the nozzle. More specifically, in the drug injector of Patent Document 1, in a first aspect, the female screw is integrally formed with the barrel. In the drug injector of Patent Document 1, in a second aspect, the female screw is rotatably provided on the outer wall of the barrel.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the first aspect of Patent Document 1, when attaching the nozzle to the barrel, it is necessary to rotate the tip of the nozzle (the tip of the discharge portion) so as to draw a circle with respect to the axis of the barrel. Further, in the first aspect, in order to keep the posture (orientation) of the discharge portion of the nozzle with respect to the flange constant, it is necessary to accurately manufacture the male screw (male screw portion) and the female screw (female screw portion).

[0006] In the second aspect of Patent Document 1, when attaching the nozzle to the barrel, it is necessary to grip the outer circumference of the mounting portion, which has an internal thread formed on its inner circumference, and rotate the tip of the nozzle in a circular motion relative to the barrel axis. Furthermore, in this second aspect, the orientation (direction) of the nozzle's discharge portion relative to the flange can be changed, but the nozzle's orientation is not stable.

[0007] This disclosure provides a drug injector that allows for easy attachment and detachment of the nozzle to the barrel and maintains a constant orientation (direction) of the nozzle relative to the barrel flange. [Means for solving the problem]

[0008] According to this disclosure, a drug injector comprises a barrel filled with a drug, a nozzle attached to the barrel, and a plunger that pushes the drug filled in the barrel toward the nozzle. The barrel includes a flange, a body continuous with the flange into which the plunger is inserted from the flange side, and a tip continuous with the body on the opposite side of the flange. The body extends from the flange in a first direction. The tip extends from the body in a second direction and communicates with the body and the nozzle. The second direction is different from the first direction and is away from the flange. The nozzle extends from the tip in a second direction and is detachably attached to the tip. [Effects of the Invention]

[0009] According to the above disclosure, the nozzle can be easily attached to and detached from the barrel, and the position (orientation) of the nozzle relative to the barrel flange can always be kept constant. [Brief explanation of the drawing]

[0010] [Figure 1] This is a side view of the drug injector. [Figure 2] This is a magnified view of the main parts of the drug injector. [Figure 3] Figure 2 shows a longitudinal cross-section of the main part. [Figure 4]This is a longitudinal cross-sectional view of the main part with the nozzle attached to the barrel. [Modes for carrying out the invention]

[0011] Embodiments of this disclosure will be described below with reference to the drawings. In the following description, the same reference numerals are used for identical components. Their names and functions are also the same. Therefore, detailed descriptions of them will not be repeated.

[0012] Figure 1 is a side view of the drug injector 1 according to this embodiment. As shown in Figure 1, the drug injector 1 comprises a barrel 10, a nozzle 20, a gasket 30, and a plunger 40. The barrel 10 is also referred to as the "outer cylinder." The plunger 40 is also referred to as the "plunger rod" or "pusher."

[0013] In Figure 1 and Figures 2 to 4 described later, the parts of the drug injector 1 are depicted as opaque for convenience, in order to make the shape of each part easier to understand. In reality, at least the barrel 10 is made of a transparent or translucent resin such as polypropylene so that the inside can be seen. It is also preferable that the nozzle 20 is made of a transparent or translucent resin. The plunger 40 is preferably opaque and colored (for example, yellow, light blue, etc.) to improve visibility.

[0014] First, let's describe the barrel 10. The barrel 10 includes a flange 11, a body 12, and a tip 13. The nozzle 20 includes a base 21 and a cylindrical part 22. The plunger 40 includes a flange 41 and a main body 42. The flange 41 is also called a "finger flange" or "finger grip."

[0015] The lumen of barrel 10 is filled with a drug. In this example, the lumen of barrel 10 is filled with a highly viscous drug. The drug is, for example, a dental material such as root canal treatment material or dental impression material. However, the drug filled in barrel 10 is not limited to highly viscous drugs. Furthermore, the drug filled in barrel 10 is not limited to dental use. The parts of barrel 10 are described in detail below.

[0016] The flange 11 is provided at the rear end of the barrel 10 (on the flange 41 side of the plunger 40). The outer circumference of the flange 11 is elliptical. In this example, the major axis of the ellipse is in the Y direction, and the minor axis is in the Z direction. The flange 11 extends in the Y direction.

[0017] The body portion 12 is continuous with the flange 11, and the plunger 40 is inserted from the flange 11 side. The body portion 12 has a substantially cylindrical outer shape. The body portion 12 extends from the flange 11 in the direction of arrow A1 (first direction). In this example, the body portion 12 extends from the flange 11 in the positive direction of the X direction.

[0018] The tip portion 13 is continuous with the body portion 12 on the side opposite to the flange 11. The tip portion 13 extends from the body portion 12 in the direction of arrow A2 (second direction) (see Figure 2). The tip portion 13 communicates with the body portion 12 and the nozzle 20. The direction of arrow A2 is different from the direction of arrow A1. The direction of arrow A2 is away from the flange 11. Thus, the tip portion 13 is inclined with respect to the body portion 12. The barrel 10 is bent by a predetermined angle at the tip side.

[0019] Next, the nozzle 20 will be described. The nozzle 20 is attached to the barrel 10. The nozzle 20 extends from the tip 13 of the barrel 10 in the direction of arrow A2. The nozzle 20 is detachably attached to the tip 13.

[0020] The base 21 of the nozzle 20 functions as an attachment portion for attaching the nozzle 20 to the barrel 10. The cylindrical portion 22 extends from the base 21 in the direction of arrow A2. A drug discharge port 22a is formed on the side opposite to the base 21 in the cylindrical portion 22. The discharge port 22a is an opening. The discharge port 22a is formed at the tip of the cylindrical portion 22. A part or all of the cylindrical portion 22 is inserted into the mouth of the patient during treatment. The cylindrical portion 22 becomes thinner as it approaches the tip side.

[0021] Next, the plunger 40 will be described. The main body portion 42 is continuous with the flange 41. A part of the main body portion 42 is fitted into the inner cavity L1 (FIG. 3) of the barrel 10. A gasket 30 is attached to the tip of the plunger 40 (specifically, the end on the side opposite to the flange 41). Specifically, the gasket 30 is attached to the main body portion 42. The gasket 30 is in sliding contact with the inner peripheral surface 1920 (see FIG. 3) of the inner cavity L1 of the barrel 10.

[0022] The plunger 40 pushes out the drug filled in the barrel 10 toward the nozzle 20 by the gasket 30. When the dentist applies a force to relatively move the flange 41 in the direction of arrow A1 with respect to the barrel 10, the gasket 30 moves in the direction of arrow A1 inside the barrel 10. As a result, the drug inside the barrel 10 is pushed out into the inner cavity L2 (FIG. 3) of the nozzle 20.

[0023] FIG. 2 is an enlarged view of the main part of the drug injector 1. Specifically, FIG. 2 is a view showing a state in which the nozzle 20 is removed from the barrel 10 in the direction of arrow A2.

[0024] As shown in FIG. 2, the tip portion 13 of the barrel 10 includes a first portion 131, a second portion 132, and a third portion 133. The first portion 131 is continuous with the body portion 12. The second portion 132 is continuous with the first portion 131 on the side opposite to the body portion 12. The third portion 133 is continuous with the second portion 132 on the side opposite to the first portion 131.

[0025] The second part 132 is cylindrical. The third part 133 extends in the direction of arrow A2. The first part 131 is curved so that the second part 132 is in the direction of arrow A2.

[0026] The tip portion 13 has a male threaded portion 1339. More specifically, the third portion 133 has a male threaded portion 1339. The male threaded portion 1339 is formed on the outer circumference of the third portion 133. The third portion 133 is cylindrical except for the threaded portion that constitutes the male threaded portion 1339.

[0027] The base 21 of the nozzle 20 has a first portion 211, a second portion 212, and a third portion 213. The second portion 212 has a front portion 2121 and a rear portion 2122. The third portion 213 is the rear end of the nozzle 20.

[0028] The first section 211 is continuous with the cylindrical section 22. The second section 212 is continuous with the first section 211 on the opposite side of the cylindrical section 22. More specifically, the front section 2121 is continuous with the first section 211. The rear section 2122 is continuous with the front section 2121 on the opposite side of the first section 211. The third section 213 is continuous with the second section 212 (more specifically, the rear section 2122) on the opposite side of the first section 211.

[0029] In this example, the outer shape (circumferential circumference) of the cross-section of the nozzle 20 is circular. The central axis J indicates the central axis of the nozzle 20. The central axis J extends in the direction of arrow A2. More specifically, the central axis J also extends in the direction opposite to that of arrow A2.

[0030] The diameter of the outer periphery of the cross-section of the first portion 211 increases as it approaches the second portion 212. The diameter of the outer periphery of the cross-section of the front portion 2121 remains constant. In this example, the diameter of the outer periphery of the cross-section of the first portion 211 is the same as the diameter of the outer periphery of the cross-section of the front portion 2121 of the second portion 212 near the boundary with the front portion 2121.

[0031] The rear portion 2122 of the second portion 212 has a larger outer diameter of its cross-section as it approaches the third portion 213. The third portion 213 has a constant outer diameter of its cross-section. In this example, the outer diameter of the cross-section of the rear portion 2122 is the same as the outer diameter of the cross-section of the third portion 213 near the boundary with the third portion 213.

[0032] When the nozzle 20 is attached to the barrel 10 (Figure 1), the central axis J of the nozzle 20 coincides with the central axes (not shown) of the second part 132 and the third part 133.

[0033] Figure 3 is a longitudinal section of the main part shown in Figure 2. First, the barrel 10 will be described. As shown in Figure 3, the barrel 10 has an inner circumferential surface 190 that constitutes the lumen L1 in which the drug is contained.

[0034] The lumen L1 includes the lumen L11 on the body portion 12 side and the lumen L12 on the tip portion 13 side. The lumen L12 connects the body portion 12 and the nozzle 20. The lumen L12 connects the lumen L11 of the body portion 12 and the lumen L2 of the nozzle 20, which will be described later.

[0035] Inner surface 190 includes inner surface 1920 and inner surface 1930. Inner surface 1920 and inner surface 1930 are continuous. Inner surface 1930 has inner surface 1931, inner surface 1932 and inner surface 1933. Inner surface 1931 and inner surface 1932 are continuous. Inner surface 1932 and inner surface 1933 are continuous.

[0036] More specifically, the body portion 12 has an inner circumferential surface 1920. The tip portion 13 has an inner circumferential surface 1930. The first portion 131 of the tip portion 13 has an inner circumferential surface 1931. The second portion 132 has an inner circumferential surface 1932. The third portion 133 has an inner circumferential surface 1933. The third portion 133 has the open end of the barrel 10 on the nozzle 20 side.

[0037] The inner circumferential surface 1932 has a diameter (distance from the central axis, not shown) that increases toward the inner circumferential surface 1933. Similarly, the inner circumferential surface 1933 also has a diameter that increases toward the nozzle 20. Thus, the inner circumferential surfaces 1932 and 1933 of the tip portion 13 have a diameter that increases toward the nozzle 20. The reason for this configuration is to facilitate the attachment of the nozzle 20. More specifically, it is to facilitate the insertion of the fourth portion 214 of the nozzle 20, which will be described later, into the lumen L12.

[0038] Conversely, the inner circumferential surface 1933 decreases in diameter toward the inner circumferential surface 1932. The inner circumferential surface 1932 decreases in diameter toward the inner circumferential surface 1931. The inner circumferential surfaces 1933 and 1932 of the tip portion 13 decrease in diameter toward the body portion 12.

[0039] In this example, the inner circumferential surface 1933 and the inner circumferential surface 1932 are continuous without any steps. The diameter of the inner circumferential surface 1933 and the diameter of the inner circumferential surface 1932 decrease at a constant rate toward the body portion 12.

[0040] The second portion 132 of the tip portion 13 has an outer circumferential surface 1325. The distance between the outer circumferential surface 1325 and the central axis (not shown) of the second portion 132 is constant.

[0041] Next, the nozzle 20 will be described. In addition to the first to third parts 211 to 213 described above, the nozzle 20 further has a fourth part 214. When the nozzle 20 is attached to the barrel 10, the lumen L2 of the nozzle 20 communicates with the lumen L1 of the barrel 10. With respect to the lumen L2 of the nozzle 20, the second part 212 and the third part 213 form the outer wall, and the fourth part 214 forms the inner wall.

[0042] The nozzle 20 has an externally exposed outer circumferential surface 250 and an inner circumferential surface 270 which is the back surface of the outer circumferential surface 250 and is located inside the outer circumferential surface 250 in the radial direction of the outer circumferential surface 250. The inner circumferential surface 270 includes an inner circumferential surface 2127 and an inner circumferential surface 2137. The outer circumferential surface 250 includes an outer circumferential surface 2125 and an outer circumferential surface 2135. The outer circumferential surface 2125 is located outside the inner circumferential surface 2127 in the radial direction of the inner circumferential surface 270. The outer circumferential surface 2135 is located outside the inner circumferential surface 2137 in the same radial direction.

[0043] The distance from the central axis J of the inner circumferential surface 2137 is longer than the distance from the central axis J of the inner circumferential surface 2127. The distance from the central axis J of the outer circumferential surface 2135 is longer than the distance from the central axis J of the outer circumferential surface 2125.

[0044] Note that inner circumferential surface 270 is an example of an "inner circumferential surface" in this disclosure. Outer circumferential surface 250 is an example of an "outer circumferential surface" in this disclosure. Inner circumferential surface 2127 is an example of a "first inner circumferential surface" in this disclosure. Inner circumferential surface 2137 is an example of a "second inner circumferential surface" in this disclosure. Outer circumferential surface 2125 is an example of a "first outer circumferential surface" in this disclosure. Outer circumferential surface 2135 is an example of a "second outer circumferential surface" in this disclosure.

[0045] The nozzle 20 further has an inner circumferential surface 290 that constitutes an inner lumen L2 through which the drug passes. The inner circumferential surface 290 includes an inner circumferential surface 2910 and an inner circumferential surface 2920. The inner circumferential surface 2910 and the inner circumferential surface 2920 are continuous. The inner circumferential surface 2910 has an inner circumferential surface 2911 and an inner circumferential surface 2914. The inner circumferential surface 2911 and the inner circumferential surface 2914 are continuous.

[0046] More specifically, the base portion 21 has the inner circumferential surface 2910 described above. The first portion 211 of the base portion 21 has the inner circumferential surface 2911. The fourth portion 214 has the inner circumferential surface 2914 and the outer circumferential surface 2145. The cylindrical portion 22 has an inner circumferential surface 2920. The inner circumferential surface 2914 is the back surface of the outer circumferential surface 2145 and is located inside the outer circumferential surface 2145 in the radial direction of the outer circumferential surface 2145.

[0047] In this example, the outer shape of the fourth portion 214 is tapered. The diameter of the inner circumferential surface 2914 is constant. The thickness of the fourth portion 214 (thickness of the inner wall) decreases as it moves away from the discharge port 22a of the nozzle 20, as shown in Figure 3. However, it is not limited to this, and the thickness of the fourth portion 214 may be constant. That is, the diameter of the outer circumferential surface 2145 may also be constant.

[0048] The second portion 212 has the outer circumferential surface 2125 and the inner circumferential surface 2127 described above. The second portion 212 further has a female threaded portion 2129. Specifically, the female threaded portion 2129 is formed on the inner circumferential surface 2127. The female threaded portion 2129 is configured to engage (screw) with the male threaded portion 1339 of the tip portion 13 of the barrel 10.

[0049] The third portion 213 has the outer circumferential surface 2135 and the inner circumferential surface 2137 described above. The third portion 213 further has a ring-shaped end face 2139. The outer circumferential surface 2135 is continuous with the outer circumferential surface 2125 of the second portion 212. The inner circumferential surface 2137 is continuous with the inner circumferential surface 2127 of the second portion 212 via the end face 2139.

[0050] The fourth portion 214 is spaced apart from the inner circumferential surfaces 2127 and 2137. As described above, the fourth portion 214 is inserted into the lumen L12 of the barrel 10.

[0051] The central axis J is the axis between the inner circumferential surfaces 290, 2127, 2137, 2125, and 2135.

[0052] As described above, the base portion 21 has an internal threaded portion 2129 formed on its internal circumferential surface 270. More specifically, the internal circumferential surface 270 has an internal circumferential surface 2127 on which the internal threaded portion 2129 is formed, and an internal circumferential surface 2137 that is further away from the cylindrical portion 22 than the internal circumferential surface 2127. The external circumferential surface 250 has an external circumferential surface 2125 located outside the internal circumferential surface 2127 in the radial direction of the internal circumferential surface 270, and an external circumferential surface 2135 located outside the internal circumferential surface 2137 in the same radial direction.

[0053] Figure 4 is a longitudinal cross-sectional view of the main part of the nozzle 20 when it is attached to the barrel 10. As shown in Figure 4, the male threaded portion 1339 of the barrel 10 and the female threaded portion 2129 of the nozzle 20 are engaged.

[0054] The fourth portion 214 of the nozzle 20 is inserted into the lumen L12 on the tip portion 13 side of the barrel 10. The outer circumferential surface 2145 of the fourth portion 214 and the inner circumferential surfaces 1933 and 1932 of the tip portion 13 are in contact.

[0055] As described above, the inner circumferential surface 1932 has a diameter that decreases towards the inner circumferential surface 1931. The outer shape of the fourth part 214 is tapered. Therefore, the inner circumferential surface 1932 and the outer circumferential surface 2145 can be brought into close contact. Thus, the gap between the inner circumferential surface 1932 and the outer circumferential surface 2145 can be eliminated. Consequently, it is possible to prevent the drug from leaking out from the gap between the inner circumferential surface 1932 and the outer circumferential surface 2145 toward the inner circumferential surface 1933.

[0056] Furthermore, the inner circumferential surface 1933 and the outer circumferential surface 2145 can be brought into close contact with each other. Therefore, the gap between the inner circumferential surface 1933 and the outer circumferential surface 2145 can be eliminated. Consequently, even if the drug leaks out from the gap between the inner circumferential surface 1932 and the outer circumferential surface 2145 toward the inner circumferential surface 1933, it can be prevented from leaking from the gap between the inner circumferential surface 1933 and the outer circumferential surface 2145 toward the male screw portion 1339 and the female screw portion 2129.

[0057] Not limited to the above, it is preferable to configure the nozzle 20 such that at least the inner circumferential surface 1932 of the inner circumferential surface 1933 contacts the outer circumferential surface 2145 of the fourth portion 214 of the nozzle 20. However, the nozzle 20 may also be configured such that only the inner circumferential surface 1933 of the inner circumferential surface 1932 contacts the outer circumferential surface 2145 of the fourth portion 214 of the nozzle 20.

[0058] As described above, the base 21 of the nozzle 20 has an umbrella structure (covering structure) that prevents saliva or blood from adhering to the inner circumferential surface 270 (particularly the inner circumferential surface 2127) shown in Figure 3. The fourth part 214 (Figure 3) corresponds to the handle of the umbrella. The first part 211, the second part 212, and the third part 213 together correspond to the compartments and main ribs of the umbrella.

[0059] In particular, a third portion 213, which does not have a female thread, is located on the opposite side of the cylindrical portion 22 from the second portion 212, where the female thread portion 2129 is formed. This third portion 213 prevents saliva or blood flying in the direction of arrows A3 and A4 in Figure 4 from adhering to the female thread portion 2129 of the second portion 212 and the male thread portion 1339 of the tip portion 13 of the barrel 10. In particular, it prevents saliva, etc., from entering the engagement portion S where the female thread portion 2129 and the male thread portion 1339 interlock. As a result, only the barrel 10 of the barrel 10 and nozzle 20 can be easily reused.

[0060] <Summary> (1) As shown in Figure 1, the drug injector 1 comprises a barrel 10 into which the drug is filled, a nozzle 20 attached to the barrel 10, a gasket 30, and a plunger 40 to which the gasket 30 is attached at the tip and which pushes the drug filled in the barrel 10 toward the nozzle 20 by the gasket 30.

[0061] The barrel 10 includes a flange 11, a body portion 12 that is continuous with the flange 11 and into which the plunger 40 is inserted from the flange 11 side, and a tip portion 13 that is continuous with the body portion 12 on the side opposite to the flange 11. The body portion 12 extends from the flange 11 in the direction of arrow A1.

[0062] As shown in Figures 1 to 4, the tip portion 13 extends from the body portion 12 in the direction of arrow A2 and communicates with the body portion 12 and the nozzle 20. The direction of arrow A2 is different from the direction of arrow A1 and is away from the flange 11. The nozzle 20 extends from the tip portion 13 in the direction of arrow A2 and is detachably attached to the tip portion 13.

[0063] With this configuration, when attaching the nozzle 20 to the barrel 10, it is not necessary to rotate the tip of the nozzle 20 (discharge port 22a) in a circular motion with respect to the central axis (not shown) of the barrel 10. Furthermore, the orientation (direction) of the nozzle 20 relative to the barrel 10 is constant. Therefore, with the drug injector 1, it is easy to attach and detach the nozzle 20 from the barrel 10, and it is possible to always maintain a constant orientation (direction) of the nozzle 20 relative to the flange 11 of the barrel 10.

[0064] (2) As shown in Figures 2 to 4, the tip portion 13 of the barrel 10 has a male threaded portion 1339. As shown in Figures 3 and 4, the nozzle 20 has a female threaded portion 2129 that engages with the male threaded portion 1339. With this configuration, the nozzle 20 can be attached to and detached from the barrel 10.

[0065] (3) As shown in Figures 3 and 4, the nozzle 20 includes (i) a base portion 21 having an outer peripheral surface 250 exposed to the outside and an inner peripheral surface 270 located inside the outer peripheral surface 250 in the radial direction with respect to the outer peripheral surface 250, and (ii) a cylindrical portion 22 extending from the base portion 21 in the direction of arrow A2 and having a drug discharge port 22a formed on the side opposite to the base portion 21. As shown in Figure 3, the inner peripheral surface 270 has an inner peripheral surface 2127 on which a female screw portion 2129 is formed and an inner peripheral surface 2137 which is further away from the cylindrical portion 22 than the inner peripheral surface 2127. As shown in Figure 3, the outer peripheral surface 250 has an outer peripheral surface 2125 located outside the inner peripheral surface 2127 in the radial direction and an outer peripheral surface 2135 located outside the inner peripheral surface 2137 in the radial direction.

[0066] With this configuration, it is possible to prevent patient saliva or blood flying towards the base 21 from adhering to the female threaded portion 2129 of the nozzle 20 and the male threaded portion 1339 of the tip portion 13 of the barrel 10.

[0067] (4) As shown in Figure 3, the central axis J of the nozzle 20 extends in the direction of arrow A2. The distance of the outer peripheral surface 2135 from the central axis J is longer than the distance of the outer peripheral surface 2125 from the central axis J. With this configuration, the adhesion of patient saliva or blood flying toward the base 21 can be suppressed even more effectively compared to the case where the distance of the outer peripheral surface 2135 from the central axis J is the same as the distance of the outer peripheral surface 2125 from the central axis J.

[0068] (5) As shown in Figure 3, the tip portion 13 has a lumen L12 that connects the body portion 12 and the nozzle 20, and the diameter of the lumen L12 increases from the body portion 12 toward the nozzle 20. That is, the diameter of the lumen L12 increases toward the direction of arrow A2. To put it another way, the tip portion 13 has at least inner circumferential surfaces 1932 and 1933 formed toward the opening end of the barrel 10 on the nozzle 20 side from the body portion 12, and the diameters of the inner circumferential surfaces 1932 and 1933 increase toward the direction of arrow A2. This allows the user to push the inner wall (fourth portion 214) of the nozzle 20 into the lumen L12, that is, to fit the nozzle 20 into the tip portion 13.

[0069] <Variation> (1) The distance from the central axis J of the outer peripheral surface 2135 of the third portion 213 of the nozzle 20 may be the same as the distance from the central axis J of the outer peripheral surface 2125 of the second portion 212 of the nozzle 20. In this case, a skirt-like portion such as the rear portion 2122 of the second portion 212 is unnecessary.

[0070] (2) The direction (angle of inclination) of arrow A2 relative to arrow A1 is determined appropriately according to the intended use of the drug injector 1.

[0071] (3) In the above description, a plunger 40 with a gasket 30 attached to its tip that pushes the chemical agent filled in the barrel 10 toward the nozzle 20 by the gasket 30 was used as an example, but the explanation is not limited to this. A non-gasket plunger without a gasket 30 attached to its tip may be used as the plunger 40 that pushes the chemical agent filled in the barrel 10 toward the nozzle 20.

[0072] (4) In the above description, a configuration in which the tip portion 13 of the barrel 10 has a male threaded portion 1339 and the nozzle 20 has a female threaded portion 2129 that engages with the male threaded portion 1339 was used as an example. However, the configuration is not limited to this. The drug injector 1 may have a female threaded portion at the tip portion 13 of the barrel 10 and a male threaded portion at the nozzle 20 that engages with the female threaded portion. For example, a female threaded portion may be formed on at least one of the inner circumferential surfaces 1933 and 1932 (Figure 3) of the tip portion 13 of the barrel 10, and a male threaded portion that engages with the female threaded portion may be formed on the outer circumferential surface 2145 (Figure 3) of the nozzle 20. With such a configuration, the nozzle 20 can also be attached to and detached from the barrel 10.

[0073] This configuration can be explained using the outer and inner walls described above as follows: The base 21 of the nozzle 20 has an outer wall and an inner wall through which the drug flows. The outer wall has an outer peripheral surface 250 and an inner peripheral surface 270 which is the back surface of the outer peripheral surface 250 and is located inside the outer peripheral surface 250 in the radial direction of the outer peripheral surface 250. The inner wall has an outer peripheral surface 2145 and an inner peripheral surface 2914 which is the back surface of the outer peripheral surface 2145 and is located inside the outer peripheral surface 2145 in the radial direction of the outer peripheral surface 2145. A male screw portion is formed on the outer peripheral surface 2145 of the inner wall. With this configuration, the outer wall can prevent patient saliva or blood flying towards the base 21 from adhering to the male screw portion of the nozzle 20 and the female screw portion of the tip 13 of the barrel 10.

[0074] The outer circumferential surface 250 of the outer wall has an outer circumferential surface 2125 and an outer circumferential surface 2135 which is further away from the cylindrical portion 22 than the outer circumferential surface 2125. The central axis J of the nozzle 20 extends in the direction of arrow A2. The distance of the outer circumferential surface 2135 of the outer wall from the central axis J is longer than the distance of the outer circumferential surface 2125 from the central axis J. Therefore, as in the embodiment described above, the adhesion of patient saliva or blood flying toward the base 21 can be further suppressed compared to the case where the distance of the outer circumferential surface 2135 from the central axis J is the same as the distance from the central axis J of the outer circumferential surface 2125.

[0075] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims, and all modifications within the meaning and scope of the claims are intended to be included. [Explanation of Symbols]

[0076] 1 Drug injector, 10 Barrel, 11, 41 Flange, 12 Body, 13 Tip, 20 Nozzle, 21 Base, 22 Cylinder, 22a Discharge port, 30 Gasket, 40 Plunger, 42 Main body, 131, 211 First part, 132, 212 Second part, 133, 213 Third part, 190, 270, 290, 1920, 1930, 1931, 1932, 1933, 2127, 2137, 2910, 2911, 2914, 2920 Inner surface, 214 Fourth part, 250, 1325, 2125, 2135, 2145 Outer surface, 1339 Male threaded part, 2121 Front part, 2122 Rear part, 2129 Female thread part, 2139 end face, J center axis, L1,L11,L12,L2 bore, S engagement part.

Claims

1. A barrel into which the drug is filled, A nozzle attached to the barrel, The barrel is filled with a plunger that pushes the drug towards the nozzle, The aforementioned barrel Flange and, A body portion that is continuous with the flange and into which the plunger is inserted from the flange side, It includes a tip portion that is continuous with the body portion on the opposite side of the flange, The body portion extends from the flange in a first direction, The aforementioned tip extends from the body in a second direction and communicates with the body and the nozzle. The second orientation is different from the first orientation and is away from the flange. A drug injector, wherein the nozzle extends from the tip in the second direction and is detachably attached to the tip.

2. The aforementioned tip portion has one of two threaded portions, a male threaded portion and a female threaded portion, which interlock with each other. The drug injector according to claim 1, wherein the nozzle has the other threaded portion of the male threaded portion and the female threaded portion.

3. The other threaded portion is the female threaded portion, The aforementioned nozzle is A base having an outer peripheral surface exposed to the outside, and an inner peripheral surface which is the back surface of the outer peripheral surface and is located inside the outer peripheral surface in the radial direction of the outer peripheral surface, It includes a cylindrical portion that extends from the base in the second direction and has a drug discharge port formed on the side opposite to the base, The inner circumferential surface has a first inner circumferential surface on which the female screw portion is formed, and a second inner circumferential surface that is further away from the cylindrical portion than the first inner circumferential surface. The drug injector according to claim 2, wherein the outer circumferential surface has a first outer circumferential surface located outside the first inner circumferential surface in the radial direction and a second outer circumferential surface located outside the second inner circumferential surface in the radial direction.

4. The central axis of the nozzle extends in the second direction, The drug injector according to claim 3, wherein the distance of the second outer surface from the central axis is longer than the distance of the first outer surface from the central axis.

5. The other threaded portion is the male threaded portion, The aforementioned nozzle is A base having an outer wall and an inner wall through which the aforementioned chemical flows, It includes a cylindrical portion that extends from the base in the second direction and has a drug discharge port formed on the side opposite to the base, Each of the outer wall and the inner wall has an outer peripheral surface and an inner peripheral surface which is the back surface of the outer peripheral surface and is located inside the outer peripheral surface in the radial direction of the outer peripheral surface. The drug injector according to claim 2, wherein the male screw portion is formed on the outer circumferential surface of the inner wall.

6. The outer circumferential surface of the outer wall has a first outer circumferential surface and a second outer circumferential surface that is further away from the cylindrical portion than the first outer circumferential surface. The central axis of the nozzle extends in the second direction, The drug injector according to claim 5, wherein the distance of the second outer surface from the central axis is longer than the distance of the first outer surface from the central axis.

Images