Syringe safety device to be attached to syringe, and safety device-equipped syringe

Abstract

To provide a syringe safety device with a structure that enables locking means to be reliably unlocked and that can reduce the thickness and size; and a safety device-equipped syringe with the syringe safety device attached thereto.SOLUTION: In a safety device-equipped syringe 1, a syringe 10 is equipped with an inner tube 20, an outer tube 30, an ejector 40, and a spring member 50. Thereby, after the injection is completed, the ejector 40 is pushed by a plunger flange 14 so as to cause a pair of inner tube deflectable pieces 21 of the inner tube 20 to bend inward, thereby capable of releasing the fixation between the inner tube 20 and the outer tube 30.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a safety device for a syringe that is pre-filled with a medicinal solution and that can move an outer cylinder that covers a puncture needle from a use position to a protection position after use, and to a syringe with a safety device equipped with this syringe safety device. [Background technology]

[0002] Background Art There are known syringe safety devices attached to syringes to prevent reuse of a syringe that has been used once and to prevent accidental contact with a puncture needle after use (see Patent Document 1).

[0003] This conventional syringe safety device comprises: an outer tube which is cylindrically shaped to be fitted onto the barrel of the syringe, and which has a large diameter section connected to the rear end of a small diameter section via a step section; an inner tube which is cylindrically shaped to be inserted into the gap between the barrel and the outer tube, and which is capable of accommodating a puncture needle, and which is capable of sliding along the outer circumferential surface of the barrel; a spring member which is built into the inner tube and which urges the inner tube forward relative to the outer tube; a locking means which locks the inner tube to the outer tube against the urging force of the spring member in a usage position where the puncture needle protrudes from its tip; and an ejector which is fixed to a plunger flange section of the syringe, is cylindrically shaped to be insertable into the outer tube, and which releases the locking by the locking means.

[0004] This locking means is configured such that a locking portion is provided at the base end of the inner cylinder, bulging in a direction away from the axis, and is locked onto the rear end surface of the stepped portion of the outer cylinder.

[0005] In addition, in this conventional syringe safety device, the inside of the large diameter part of the outer barrel is provided with an outer barrel fixing part that extends rearward from four equally spaced positions in the circumferential direction and snap-fits the barrel flange part, and a pair of elastic tabs that are arranged in the gaps in the outer barrel fixing part in the circumferential direction. The outer barrel fixing part is substantially L-shaped, approaching the axis of the puncture needle from the inner circumferential surface of the large diameter part and then bending rearward, and the elastic tab is inclined so as to gradually approach the axis as it moves rearward from the inner circumferential surface of the large diameter part.

[0006] In a conventional syringe safety device having this configuration, when the plunger is pushed forward to discharge the liquid medicine, the peripheral edge of the tip of the cylindrical ejector pushes down the pair of elastic tabs in a direction in which their tips approach each other. The elastic tabs then push the locking portion of the inner cylinder in a direction approaching the axis and separate it from the rear end face of the stepped portion of the outer cylinder, releasing the locking by the locking means. As a result, the inner cylinder is pushed forward by the biasing force of the spring member to a protection position in which the puncture needle is stored up to its tip.

[0007] As described above, in the conventional syringe safety device, the puncture needle is covered by the inner cylinder at the same time as the medicinal liquid is discharged, thereby preventing accidental contact with the puncture needle after use. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Special Publication No. 2007-508883 Summary of the Invention [Problem to be solved by the invention]

[0009] However, in conventional syringe safety devices, the forward movement of the ejector causes the elastic tab to swing, and the swinging elastic tab pushes the locking portion of the inner cylinder closer to the axis. As a result, the release of the lock by the ejector is indirect, and there is a risk that the release of the lock will not operate smoothly, particularly if the plunger is tilted even slightly relative to the barrel.

[0010] In addition, the ejector of the conventional syringe safety device is cylindrical and needs to move forward beyond the barrel flange of the syringe and the barrel fixing part that fixes it, so it needs to be designed with a larger diameter than the barrel fixing part. As a result, the large diameter part of the barrel that fits over the cylindrical ejector needs to be designed with an even larger diameter.

[0011] Similarly, since this cylindrical ejector pushes the tip end of the resilient tab forward, the large diameter portion of the outer cylinder that supports the base end of the resilient tab must be designed to have a larger diameter than the ejector for this reason as well.

[0012] Therefore, the present invention has been made in consideration of the above problems, and has an object to provide a syringe safety device that can reliably release the locking of the locking means and has a configuration that allows the device to be made smaller by reducing its thickness, and a syringe with a safety device equipped with this syringe safety device. [Means for solving the problem]

[0013] The syringe safety device of the present invention is a syringe safety device attached to a syringe including: a barrel having a puncture needle at a front end and a barrel flange portion at a rear end, the barrel containing a medicinal solution; and a plunger whose front end is slidably inserted from the rear end side of the barrel and has a plunger flange portion at its rear end, wherein when a direction along the axis of the puncture needle is defined as a front-rear direction, a first direction perpendicular to the front-rear direction is defined as a top-bottom direction, and a second direction perpendicular to the front-rear direction and the top-bottom direction is defined as a left-right direction, the syringe safety device comprises an inner cylinder which is cylindrically fitted to the outside of the barrel and fixed to the barrel flange portion, an outer cylinder which is cylindrically fitted to the outside of the barrel and the inner cylinder so as to be able to house the puncture needle and is slidable along the outer circumferential surface of the barrel, a spring member which is built into the outer cylinder and biases the inner cylinder rearward relative to the outer cylinder, and a spring member which biases the inner cylinder so that the puncture needle is moved forward and backward relative to the outer cylinder. the inner cylinder has an inner cylinder fixing part provided at its rear end and fitted to the outside of the barrel flange part, the inner cylinder fixing part has an ejector passing groove part recessed from the front end to the rear end of the inner cylinder fixing part in a direction approaching the axis, the ejector has a release protrusion extending forward from a vertical end of the front end and capable of passing through the ejector passing groove part, and the locking means is configured to be releasable by a front end of the release protrusion of the ejector which is pushed forward via the plunger flange part of the plunger when the plunger is displaced forward (hereinafter referred to as "the syringe safety device of the first invention"). In the syringe safety device of the first invention, the ejector has a release protrusion facing forward, which can pass through an ejector passing groove provided in the inner cylinder fixing portion and is positioned behind the locking means.

[0014] Therefore, when the ejector is displaced forward via the plunger, the front end of the release protrusion of the ejector can release the locking means.

[0015] Therefore, according to the syringe safety device of the first aspect of the present invention, since the release of the locking is directly performed by the ejector, the locking of the locking means can be released reliably.

[0016] Furthermore, in the syringe safety device of the first present invention, the inner tube fixing portion is recessed in the front-to-rear direction to provide a groove portion for passing the ejector, and the release piece can pass through this groove portion for passing the ejector. Therefore, in the syringe with safety device of the first present invention, there is no need to design the ejector to have a larger diameter than the inner tube fixing portion, and therefore there is no need to design the outer tube that fits around this ejector to have a larger diameter.

[0017] Therefore, according to the first syringe safety device of the present invention, the thickness can be suppressed to make the device smaller. Note that the present invention is a creation of a configuration that allows the thickness to be suppressed, and the actual diameter of the device is a matter of design. Therefore, a syringe safety device employing the configuration of the present invention falls within the technical scope of the present invention even if the actual diameter is large.

[0018] The syringe safety device of the present invention is a syringe safety device that is attached to a syringe including: a barrel having a puncture needle at a front end and a barrel flange portion at a rear end, the barrel containing a medicinal solution; and a plunger whose front end is slidably inserted from the rear end side of the barrel and has a plunger flange portion at its rear end, the syringe safety device being configured as follows: when a direction along the axis of the puncture needle is defined as a front-rear direction, a first direction perpendicular to the front-rear direction is defined as a top-down direction, and a second direction perpendicular to the front-rear direction and the top-down direction is defined as a left-right direction, the syringe safety device is tubular and fitted to the outside of the barrel, and has a plunger flange portion the puncture needle is inserted into the barrel and fixed to the barrel; an outer tube that is cylindrical and can house the puncture needle by being fitted to the outside of the barrel and the inner tube and can slide along the outer circumferential surface of the barrel; a spring member that is built into the outer tube and biases the inner tube rearward relative to the outer tube; a locking means that locks the inner tube in a use position where the puncture needle protrudes from the front end of the outer tube against the biasing force of the spring member; and a cylindrical ejector that is fitted inside the outer tube and releases the locking by the locking means. The inner tube comprises a cylindrical inner tube main body and an inner tube step portion that is connected to the rear end of the inner tube main body. and an inner tube fixing portion having an outer diameter larger than that of the inner tube main body portion and fitted to the outside of the barrel flange portion, the inner tube main body portion having a first inner tube groove portion adjacent to the inner tube step portion and extending along the front-rear direction when viewed along the vertical direction and having a U-shaped shape with an open front side, an inner tube swinging piece surrounded by the first inner tube groove portion and swingable in the vertical direction, an inner tube releasing portion provided at a rear end of the inner tube swinging piece, and an inner tube engaging portion provided adjacent to the inner tube releasing portion of the inner tube swinging piece with a gap therebetween and bulging in a direction away from the axis along the vertical direction; the inner cylinder fixing portion is provided at a position adjacent to the inner cylinder swinging piece and has an ejector passage groove portion recessed from the front end to the rear end of the inner cylinder fixing portion in a direction approaching the axis, the ejector has a release protrusion extending forward from the vertical end of the front end and narrower and thinner than the ejector passage groove portion, and an ejector release portion provided at the front end of the release protrusion, the outer cylinder has an outer cylinder locking portion extending from the vertical end of its inner circumferential surface in a direction approaching the axis and disposed in a gap between the inner cylinder locking portion and the inner cylinder release portion at the use position, and the locking means isThe syringe safety device is configured such that, in a state where the release protrusion of the ejector is inserted from the rear side into the ejector passage groove of the inner cylinder and the ejector release portion is disposed behind the inner cylinder release portion, the outer cylinder is fitted outward from the front side of the inner cylinder and the rear end of the inner cylinder locking portion is engaged with the front end of the outer cylinder locking portion, thereby allowing the syringe safety device to be locked at the use position; and, when the plunger is displaced forward, the ejector release portion of the ejector, which is pushed forward via the plunger flange portion of the plunger, displaces the inner cylinder release portion toward the axis, thereby causing the inner cylinder swing piece to swing and the inner cylinder locking portion provided on the inner cylinder swing piece to move away from the outer cylinder locking portion, thereby allowing the lock to be released (hereinafter referred to as the "second syringe safety device of the present invention").

[0019] In the syringe safety device of the second invention, the locking means locks the puncture needle in the use position by engaging the outer barrel locking portion of the outer barrel with the inner barrel locking portion provided on the inner barrel swinging piece of the inner barrel. In contrast, the ejector of the syringe with safety device of the second invention has a thin plate-like release piece extending forward, and this release piece can pass through an ejector passing groove provided in the inner barrel fixing portion that expands in diameter at the rear end of the inner barrel, and is located behind the inner barrel release piece.

[0020] Therefore, when the ejector is displaced forward via the plunger, the front end of the ejector's release protrusion (ejector release portion) can displace the inner cylinder release portion toward the axis. Since this inner cylinder release portion is provided on an inner cylinder swinging piece that can swing up and down, when the inner cylinder release portion is displaced toward the axis, the inner cylinder swinging piece on which it is provided is displaced toward the axis. Since the inner cylinder swinging piece is also provided with the inner cylinder locking portion described above, the inner cylinder locking portion is also displaced toward the axis by the ejector together with the inner cylinder release portion and the inner cylinder swinging piece. As a result, the inner cylinder locking portion is separated from the outer cylinder locking portion described above, and the locking by the locking means is released.

[0021] Therefore, according to the syringe safety device of the second aspect of the present invention, since the release of the locking is directly performed by the ejector, the locking of the locking means can be released reliably.

[0022] In the second syringe safety device of the present invention, the inner cylinder fixing portion, which expands in diameter at the rear end of the inner cylinder, is recessed in the front-rear direction to provide a groove portion for the ejector to pass through. The release piece provided on the ejector is thin and configured to pass through this ejector passage groove. Therefore, in the syringe with a safety device of the second invention, there is no need to design the ejector to have a larger diameter than the inner cylinder fixing part, and therefore there is no need to design the outer cylinder that fits over the ejector to have a larger diameter.

[0023] Therefore, according to the second syringe safety device of the present invention, the thickness can be reduced to make the device smaller. Note that the present invention is a creation of a configuration that allows the thickness to be reduced, and the actual diameter of the device is a matter of design. Therefore, a syringe safety device employing the configuration of the present invention falls within the technical scope of the present invention even if the actual diameter is large.

[0024] In the second syringe safety device of the present invention, it is preferable that the release piece is configured to be able to swing in the vertical direction, the ejector release portion is formed in a convex shape that bulges in the vertical direction toward the axis and has a slope on the front side, and when the release piece of the ejector is inserted into the ejector passing groove portion of the inner cylinder, the release piece is caused to swing in the vertical direction so that it overcomes the ejector passing groove portion and is positioned at the rear side of the inner cylinder release portion, and when the plunger is displaced forward, the front slope is pushed forward and the inner cylinder release portion is pushed down while sliding toward the axis (hereinafter referred to as the "third syringe safety device of the present invention").

[0025] In the syringe safety device of the third invention, the ejector release portion provided at the front end of the release piece is formed in a convex shape that bulges in the direction approaching the axis and has a slope on the front side, so that when the ejector is displaced forward, the slope allows the inner cylinder release portion to be pushed down while sliding toward the axis. This makes it possible to push down the inner cylinder rocking piece provided with the inner cylinder release portion together with the inner cylinder locking portion provided thereon, separating it from the outer cylinder locking portion, and releasing the locking by the locking means.

[0026] Therefore, according to the syringe safety device of the third aspect of the present invention, the locking of the locking means can be released more reliably.

[0027] In the syringe safety device of the third aspect of the present invention, the ejector release portion provided at the front end of the release piece bulges in a direction approaching the axis. However, since this release piece is configured to be swingable in the vertical direction, the ejector release portion can be moved over the ejector passage groove of the inner cylinder by swinging it in the vertical direction when inserted into the ejector passage groove of the inner cylinder and positioned behind the inner cylinder release portion. Therefore, in the syringe safety device of the second aspect of the present invention, even if the ejector release portion bulges in a direction approaching the axis, there is no need to design the ejector to have a larger diameter than the inner cylinder fixing portion, and therefore there is no need to design the outer cylinder into which the ejector is fitted to have a larger diameter.

[0028] Therefore, according to the syringe safety device of the third aspect of the present invention, the thickness can be reduced to make it smaller.

[0029] In the third syringe safety device of the present invention, it is preferable that the inner tube has a return prevention piece that extends forward from the front left-right end of the inner tube fixing part in a direction gradually moving away from the axis to a position that exceeds the inner diameter of the rear end of the outer tube, and that is elastically deformable in the left-right direction, and a return prevention end face that is provided at the front end of the return prevention piece and engages with the rear end of the outer tube, and that the return prevention piece is housed in the outer tube at the usage position by fitting the outer tube to the outside while pushing the return prevention piece down in a direction approaching the axis, and that when the locking is released, the return prevention piece is displaced rearward relative to the outer tube to a position rearward beyond the rear end of the outer tube by the biasing force of the spring member (hereinafter referred to as the "fourth syringe safety device of the present invention").

[0030] In the syringe safety device of the fourth aspect of the present invention, the inner cylinder is provided with a return prevention piece that is elastically deformable in the left-right direction. This return prevention piece is stored in the outer cylinder at the use position by fitting the outer cylinder to the outside while pushing it down in the direction approaching the axis, but when the return prevention piece is displaced rearward relative to the outer cylinder beyond the rear end thereof by the biasing force of the spring member after the engagement is released, it elastically deforms and expands in the left-right direction to a position exceeding the inner diameter of the rear end of the outer cylinder.

[0031] Furthermore, a return prevention end surface is formed at the front end of this return prevention piece to engage with the rear end of the outer tube, so that even if the inner tube is advanced (displaced forward) relative to the outer tube in an attempt to return the puncture needle to the usage position again, the return prevention end surface of the inner tube engages with the rear end of the outer tube, preventing further advancement.

[0032] Therefore, according to the syringe safety device of the fourth aspect of the present invention, it is possible to further prevent reuse of a syringe that has been used once, and also to prevent accidental contact with a puncture needle after use.

[0033] Furthermore, in the syringe safety device of the fourth invention, the return prevention piece can be housed in the barrel by being elastically deformed and pushed down in a direction approaching the axis at the use position, so there is no need to make the barrel thicker. Therefore, according to the syringe safety device of the fourth invention, the barrel can be made smaller by suppressing its thickness.

[0034] In the fourth syringe safety device of the present invention, it is preferable that the return prevention end surface is formed concavely toward the rear when viewed in the vertical direction, and the rear end of the barrel is formed convexly toward the rear at a position where it engages with the return prevention end surface when viewed in the vertical direction, and is capable of fitting with the return prevention end surface (hereinafter referred to as the "fifth syringe safety device of the present invention").

[0035] In the fifth syringe safety device of the present invention, the return prevention end face of the inner tube and the rear end of the outer tube, which collide when the inner tube is advanced relative to the outer tube to return the puncture needle to the usage position again, are formed into a concave and convex shape, respectively, so that they can be fitted together, thereby more reliably preventing further advancement.

[0036] Therefore, according to the syringe safety device of the fifth aspect of the present invention, it is possible to further prevent reuse of a syringe that has been used once, and also to prevent accidental contact with a puncture needle after use.

[0037] In addition, in the syringe safety device of the fifth aspect of the present invention, the return prevention end surface of the inner cylinder is concave toward the rear, and the rear end of the outer cylinder is convex toward the rear, and the shape of both is changed only in the front-rear direction, so there is no need to increase the diameter of the inner cylinder and the outer cylinder. Therefore, according to the syringe safety device of the fourth aspect of the present invention, the thickness can be suppressed to make it smaller.

[0038] Moreover, in the syringe safety devices of the fourth and fifth aspects of the present invention, the anti-return piece is configured to be swingable in the left-right direction by being extended forward from the front end surface of the inner cylinder fixing portion in the form of a thin plate, and the inner cylinder is provided by cutting out a cylindrical portion that overlaps with the anti-return piece when viewed along the left-right direction, and preferably has a storage hole portion for storing the anti-return piece that has swung in a direction approaching the axis (hereinafter referred to as the "sixth syringe safety device of the present invention").

[0039] In the sixth syringe safety device of the present invention, the anti-return piece extends forward from the front end face of the inner cylinder fixing part in a thin plate shape, so there is no need to make the diameter of the inner cylinder thicker. Meanwhile, the inner cylinder has a storage hole for storing the anti-return piece by cutting out a portion of the cylindrical part that overlaps with the anti-return piece, so that the clearance for the anti-return piece to swing can be secured without significantly extending it in a direction away from the axis.

[0040] Therefore, according to the syringe safety device of the sixth aspect of the present invention, the thickness can be reduced to make it smaller.

[0041] Alternatively, in the syringe safety devices of the fourth and fifth inventions, it is preferable that the anti-return piece has a main body portion having the anti-return end surface at a front end and spaced apart from the outer peripheral surface of the inner cylinder, a swinging connection piece extending from the left-right end portions of the outer peripheral surface of the inner cylinder in a direction away from the axis along the left-right direction and connected to the main body portion, causing the main body portion to swing in the front-rear direction, and a support portion provided at the rear end of the main body portion and contacting the front end of the inner cylinder fixing portion to prevent the main body portion from swinging rearward (hereinafter referred to as the "seventh invention of the syringe safety device").

[0042] In the syringe safety device of the seventh aspect of the present invention, the anti-return piece is basically swung back and forth by the swinging connecting piece.

[0043] However, since the support portion provided at the rear end of the main body of the return prevention piece comes into contact with the front end of the inner cylinder fixing portion to prevent the inner cylinder from swinging backward, even if the inner cylinder is moved forward relative to the outer cylinder after use, the main body colliding with the rear end of the outer cylinder prevents further forward movement. Thus, according to the syringe safety device of the sixth aspect of the present invention, it is possible to further prevent reuse of a syringe that has been used once, and to prevent accidental contact with a puncture needle after use.

[0044] On the other hand, the anti-return piece can be swung forward by the swivel connecting piece, and since this swivel connecting piece extends in a direction away from the axis, when the main body swings forward, it is also displaced in a direction closer to the axis as a result of swinging in an arc.

[0045] Therefore, in the syringe safety device of the seventh aspect of the present invention, the return prevention piece can be pushed forward in the use position and pushed down in the direction approaching the axis to be housed in the barrel, so there is no need to make the barrel thicker. Therefore, according to the syringe safety device of the seventh aspect of the present invention, the barrel can be made smaller by suppressing its thickness.

[0046] Furthermore, in the seventh syringe safety device of the present invention, it is preferable that the main body has a hollowed-out portion in the middle in the front-to-rear direction, where only a part in the up-down direction and a part in the left-right direction are cut out (hereinafter referred to as "the eighth syringe safety device of the present invention").

[0047] In the syringe safety device of the eighth aspect of the present invention, even if the inner cylinder is pinched between the rear end of the outer cylinder and the front end of the inner cylinder fixing part and a crushing load is applied in the front-rear direction when the inner cylinder is advanced relative to the outer cylinder after use, the main body is formed in a strong rectangular parallelepiped shape, so that unintended deformation is unlikely to occur. Therefore, the syringe safety device of the seventh aspect of the present invention can further prevent reuse of a used syringe and prevent accidental contact with a used puncture needle.

[0048] Furthermore, in the eighth syringe safety device of the present invention, it is preferable that the main body has a hollowed-out portion in the middle in the front-to-rear direction, where only a part in the up-down direction and a part in the left-right direction are cut out (hereinafter referred to as the "ninth syringe safety device of the present invention").

[0049] In the syringe safety device of the ninth aspect of the present invention, the main body is hollowed out from its rectangular parallelepiped shape, thereby making it possible to prevent the occurrence of sink marks and voids.

[0050] On the other hand, the main body is a middle portion in the front-to-rear direction, and only a part in the up-down direction and a part in the left-right direction are cut out, so that what remains is a plate-like portion on the front side that includes the anti-return end face and extends in the up-down and left-right directions, and a plate-like portion on the rear side that includes the support portion and extends in the up-down and left-right directions, and further, the two plate-like portions connecting the two remain as the plate-like portion extending in the front-to-rear and up-down directions and the plate-like portion extending in the front-to-rear and left-right directions intersect and extend, so that the reduction in strength is kept to a minimum.

[0051] Therefore, in the syringe safety device of the ninth aspect of the present invention, even if the inner cylinder is pinched between the rear end of the outer cylinder and the front end of the inner cylinder fixing part and a crushing load is applied in the front-rear direction when the inner cylinder is advanced relative to the outer cylinder after use, unintended deformation of the main body is unlikely to occur. Therefore, the syringe safety device of the ninth aspect of the present invention can further prevent reuse of a syringe that has been used once, and can prevent accidental contact with a puncture needle after use.

[0052] The syringe with a safety device of the present invention is characterized by comprising the syringe and a syringe safety device of the ninth aspect of the present invention that is attached to the syringe (hereinafter referred to as the "syringe with a safety device of the tenth aspect of the present invention").

[0053] According to the syringe with a safety device of the tenth aspect of the present invention, the ejector directly releases the lock, so that the lock of the locking means can be released reliably. Also, according to the syringe with a safety device of the tenth aspect of the present invention, the thickness can be suppressed to make it compact. [Brief description of the drawings]

[0054] [Figure 1A] FIG. 1 is a perspective view showing a syringe with a safety device according to a first embodiment of the present invention, in a state prior to use. [Figure 1B] FIG. 1 is a perspective view showing a syringe with a safety device according to a first embodiment of the present invention, in a state after use. [Diagram 2] FIG. 1 is an exploded perspective view showing a schematic configuration of a syringe with a safety device according to a first embodiment. [Figure 3A]FIG. 1 is a longitudinal sectional view showing a schematic configuration of a syringe with a safety device according to a first embodiment before use. [Figure 3B] FIG. 1 is a cross-sectional view showing a schematic configuration of a syringe with a safety device according to a first embodiment before use. [Figure 4A] FIG. 2 is a longitudinal sectional view showing a schematic configuration of the syringe with a safety device according to the first embodiment after use. [Figure 4B] FIG. 2 is a cross-sectional view showing a schematic configuration of the syringe with a safety device according to the first embodiment after use. [Figure 5A] FIG. 2 is a first perspective view showing an assembly process for the syringe with a safety device according to the first embodiment, illustrating an assembly state in which a spring member is inserted into an inner cylinder; [Figure 5B] FIG. 11 is a second perspective view showing the assembly process of the syringe with a safety device of the first embodiment, illustrating the assembly state in which the inner cylinder, the ejector, and the spring member are inserted into the outer cylinder. [Figure 5C] FIG. 11 is a third perspective view showing the assembly process of the syringe with a safety device according to the first embodiment, illustrating the state in which the barrel is attached. [Figure 5D] FIG. 13 is a fourth perspective view showing the assembly process of the syringe with a safety device of the first embodiment, illustrating the state in which the plunger rod is attached. [Figure 6] FIG. 2 is a cross-sectional view showing the operation of the syringe with a safety device of the first embodiment, illustrating a state in which the plunger flange portion is pressed, the ejector is actuated, and the snap-fit ​​protrusion of the inner cylinder is disengaged. [Figure 7] FIG. 2 is a sectional perspective view showing the operation of the syringe with a safety device of the first embodiment, illustrating a locked state when the inner cylinder and the syringe are moved rearward. [Figure 8] FIG. 11 is an exploded perspective view showing a modified example of the syringe with a safety device according to the second embodiment of the present invention. [Figure 9A] FIG. 11 is a longitudinal sectional view showing a schematic configuration of a syringe with a safety device according to a second embodiment before use. [Figure 9B] FIG. 11 is a cross-sectional view showing a schematic configuration of a syringe with a safety device according to a second embodiment before use. [Figure 10A]FIG. 11 is a longitudinal sectional view showing a schematic configuration of a syringe with a safety device according to a second embodiment after use. [Figure 10B] FIG. 11 is a cross-sectional view showing a schematic configuration of a syringe with a safety device according to a second embodiment after use. [Figure 11] FIG. 13 is a partially enlarged cross-sectional view illustrating a state in which the return prevention piece of the syringe with safety device of the second embodiment is in the stored position. [Figure 12] FIG. 13 is a partially enlarged cross-sectional view illustrating a state in which the return prevention piece of the syringe with safety device of the second embodiment is in the return prevention position. [Figure 13] FIG. 2 is a front view showing the configuration of a finger grip used in the syringe with a safety device of the present invention. [Figure 14] FIG. 2 is a plan view showing the configuration of a syringe finger grip with a safety device according to the present invention. [Figure 15] 12 is a cross-sectional view of the syringe with a safety device according to the present invention taken along the line CC in FIG. 11 . [Figure 16] FIG. 2 is a front view showing how a finger grip is attached to the syringe with a safety device of the present invention. [Figure 17] FIG. 2 is a rear perspective view showing the state in which the finger grip is attached to the syringe with safety device of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0055] 1A to 7, a syringe with a safety device 1 and a syringe safety device 2 attached to the syringe according to a first embodiment of the present invention will be described below. The syringe with a safety device 1 of the present invention is a prefilled syringe that is equipped with a safety device that can protect the puncture needle after use (after injection is completed) and contains a medicinal solution in advance, making it ready for injection.

[0056] FIG. 1a shows a state before use of the safety syringe 1 according to the first embodiment of the present invention, and FIG. 1b shows a state after use of the safety syringe 1 according to the first embodiment of the present invention. FIG. 2 is an exploded perspective view showing a schematic configuration of the safety syringe 1. FIG. 3A shows a vertical vertical section of the safety syringe 1 before use, and FIG. 3B shows a horizontal cross section of the safety syringe 1 before use. FIG. 4A shows a vertical vertical section of the safety syringe 1 after use, and FIG. 4B shows a horizontal cross section of the safety syringe 1 after use. Here, FIG. 3A and FIG. 4A are vertical sections along the axis (vertical plane), and FIG. 3B and FIG. 4B are horizontal cross sections along the axis (horizontal plane). In this specification, the "state before use" refers to a state before injection, and the "state after use" refers to a state after injection is completed. Moreover, the "tip side (corresponding to the front end side of the present invention)" is the side where the puncture needle is located, and the "rear end side" is the side where the plunger flange portion is located.

[0057] As shown in Figures 1A to 4B, the syringe with a safety device 1 includes a syringe 10, an inner cylinder 20, an outer cylinder 30, an ejector 40, a spring member 50, and a cap 60. In this embodiment, the syringe safety device 2 is composed of the inner cylinder 20, the outer cylinder 30, the ejector 40, and the spring member 50. Of these, the inner cylinder 20, the outer cylinder 30, the ejector 40, and the spring member 50 correspond to the syringe safety device 2 of the present invention (hereinafter simply referred to as the "safety device 2").

[0058] The syringe 10 includes a barrel 11, a gasket 12 that slides in the barrel 11 to discharge the stored liquid medicine, a plunger rod 13, a plunger flange portion 14 provided on the rear end side of the plunger rod 13, and a puncture needle 15 attached to the tip of the barrel 11. The rear end of the barrel 11 has a barrel flange portion 11a. The gasket 12 is made of a packing such as butyl rubber or a thermoplastic elastomer that airtightly seals the space between the barrel 11 and the plunger rod 13. A screw hole is provided on the rear end side of the gasket 12 for threading the male screw 13a at the tip of the plunger rod 13. The plunger flange portion 14 is formed so that its outer diameter is smaller than the inner diameter of the rear end of the outer cylinder 30 and can be attached to the rear end of the ejector 40. Before use, the puncture needle 15 is protected by a cap 60.

[0059] The inner tube 20 is formed, for example, from a resin material into a hollow cylindrical shape, and is composed of an inner tube main body portion 20a on the tip side and an inner tube fixing portion 20b on the rear end side. The inner tube main body portion 20a on the tip side is formed so as to be insertable into the medium diameter portion 32 of the outer tube 30, and the inner tube fixing portion 20b on the rear end side is formed so as to be insertable into the large diameter portion 31 of the outer tube 30.

[0060] A pair of inner cylinder swing pieces 21 are provided at a position close to the rear end side of the inner cylinder main body 20a of the inner cylinder 20. The pair of inner cylinder swing pieces 21 are formed by providing a C-shaped slit s (corresponding to the "first inner cylinder groove" in this embodiment) in the side wall of the inner cylinder 20. Each of the pair of inner cylinder swing pieces 21 is provided with an inner cylinder release part 21b having an inclined surface 21a that abuts against the ejector 40 at the tip, and an inner cylinder locking part 21c for fitting into the inner cylinder swing piece fitting groove 32b of the outer cylinder 30 is provided on the outer peripheral surface. The pair of inner cylinder swing pieces 21 of the inner cylinder 20 are formed elastically deformable so that the inner cylinder locking part 21c is displaced between an engagement position and a disengagement position to perform the function of releasing the fixation between the inner cylinder 20 and the outer cylinder 30.

[0061] In addition, a pair of return prevention pieces 22 are provided at the rear end side of the inner tube 20 at a position rotated 90 degrees relative to the pair of inner tube swing pieces 21. The main body portion 22a of the pair of return prevention pieces 22 is connected to the inner tube fixed portion 20b of the inner tube 20, and the tip portion 22b having the return prevention end surface 22f is formed wider in the radial direction than the main body portion 22a. The outer periphery of the tip portion 22b is formed so as to be able to be fitted into the opening portion 31b of the outer tube 30. The pair of return prevention pieces 22 are elastically deformable so as to be displaced between a storage position in which they are stored in the outer tube 30 and a return prevention position in which they extend out from the outer tube 30. That is, the pair of return prevention pieces 22 are configured to expand from the surface of the inner tube 20 when the rear end portion of the inner tube 20 exits the outer tube 30, and to abut against the rear end of the large diameter portion 31 of the outer tube 30, thereby preventing the inner tube 20 from returning to the tip side. The inner cylinder 20 has a notch in a cylindrical portion overlapping with the return prevention piece 22, and this notch becomes a storage hole 27 for storing the return prevention piece 22 when it swings in a direction approaching the axis. The return prevention end surface of the tip portion 22b may be formed in a concave shape facing rearward when viewed in the up-down direction.

[0062] In addition, a pair of anti-slip pieces 23 are provided on the tip side of the inner tube 20 (i.e., at a position collinear with the return prevention piece 22 in the axial direction), and anti-slip protrusions 23a are provided on the outer peripheral surfaces of the tip sides of the pair of anti-slip pieces 23. The pair of anti-slip pieces 23 are configured such that, when the rear end of the inner tube 20 comes out of the outer tube 30, the anti-slip protrusions 23a slide along a pair of slits 32a of the outer tube 30 and engage with outer tube locking portions 34a between the large diameter portion 31 and the medium diameter portion 32 of the outer tube 30, thereby preventing the inner tube 20 from coming out of the outer tube 30.

[0063] Also, a fitting portion 24 for fitting the barrel flange portion 11a of the barrel 11 into the inner cylinder fixing portion 20b on the rear end side of the inner cylinder 20, and an ejector passing groove portion 25 for passing the pair of release protrusions 41 of the ejector 40 are provided. Furthermore, a plurality of spring abutment ribs 26 for restricting the rear end of the spring member 50 are provided on the rear end side of the inner peripheral surface of the inner cylinder 20. The barrel 11 is fixed to the inner cylinder 20 by the fitting portion 24. As a result, when the engagement of the pair of inner cylinder swinging pieces 21 is released, the barrel 11 moves together with the inner cylinder 20.

[0064] The outer cylinder 30 is formed, for example, from a resin material into a three-stage hollow cylinder shape in which a large diameter section 31, a medium diameter section 32, and a small diameter section 33 are integrally formed. In the outer cylinder 30, the large diameter section 31 is formed into a substantially elliptical cylindrical shape, and the rear end of the inner cylinder 20 and the ejector 40 can be stored inside this large diameter section 31. In addition, a pair of grooves 31a extending in the axial direction are formed at opposing positions on the inner peripheral surface of the large diameter section 31. Furthermore, a pair of openings 31b are provided on the tip side of the large diameter section 31 and at positions rotated 90 degrees from the pair of grooves 31a.

[0065] In the outer tube 30, the medium diameter section 32 and the small diameter section 33 are formed into a circular cylindrical shape. The medium diameter section 32 is formed so that the inner tube main body section 20a on the tip side of the inner tube 20 can be inserted inside, and a pair of slits 32a extending in the axial direction are provided at positions facing the side walls of the medium diameter section 32. The tips of the pair of slits 32a extend partially into the small diameter section 33. In addition, a pair of inner tube swing piece fitting grooves 32b into which the inner tube locking sections 21c of the pair of inner tube swing pieces 21 of the inner tube 20 are fitted are provided in the rear end side walls of the medium diameter section 32 at positions rotated 90 degrees relative to the pair of slits 32a.

[0066] Furthermore, a flange portion 34 is provided between the large diameter portion 31 and the medium diameter portion 32 so that the user can grasp it. The flange portion 34 is a portion on which, for example, the index finger and middle finger are placed when the user presses the plunger flange portion 14 with the thumb.

[0067] The flange portion 34 has an elliptical outer shape with a flat portion 34d formed by linearly cutting out the minor diameter side of a plate-like body formed in a roughly elliptical disk shape, i.e., the side on which the removal prevention piece 23 is formed. By having such a linear flat portion 34d, it is possible to prevent the ejector 40 placed horizontally from unintentionally rolling.

[0068] The outer cylinder 30 may be made of, for example, a transparent or semi-transparent material through which light can pass. In this case, the liquid medicine in the syringe 10 can be observed from the outside. That is, the syringe 1 with a safety device according to this embodiment allows the user to visually check the amount of the liquid medicine in the syringe 10 and the operating state of the gasket 12 during use.

[0069] The ejector 40 is formed, for example, from a resin material in a substantially elliptical short cylinder shape. A pair of release protrusions 41 is provided on the tip side of the ejector 40. The pair of release protrusions 41 have an ejector release portion 41a at the tip, and are configured so that, after the injection is completed, the ejector 40 is pushed by the plunger flange portion 14 to push and bend the pair of inner cylinder swinging pieces 21 of the inner cylinder 20. In addition, ribs 42 extending in the axial direction are formed on the outer peripheral surfaces of the pair of release protrusions 41. The ribs 42 are formed so as to be able to fit into the grooves 31a (see FIG. 6) extending in the axial direction formed on the inner peripheral surface of the large diameter portion 31 of the outer cylinder 30, and define the circumferential position of the ejector 40 and guide the sliding of the ejector 40 in the front-rear direction.

[0070] The spring member 50 is a compression coil spring made of an appropriate metal such as stainless steel. One end (front end) of the spring member 50 abuts against the front end of the medium diameter portion 32 of the outer tube 30, and the other end (rear end) abuts against the front ends of the spring abutment ribs 26 on the inner peripheral surface of the inner tube 20, and is disposed so as to urge the inner tube 20 rearward and the outer tube 30 toward the front end side. The syringe 10 is inserted inside the spring member 50. In the initial state, the spring member 50 is compressed between the front end of the medium diameter portion 32 of the outer tube 30 and a plurality of vertical ribs (parallel to the central axis direction) formed on the inner peripheral surface of the inner tube 20, extending from the base end side to the front end side, and protruding in the central axis direction. That is, before use, the spring member 50 is located on the rear end side of the syringe 10.

[0071] The cap 60 is made of an appropriate resin such as polypropylene, and is a removable, approximately truncated cone-shaped cap that protects the puncture needle before use. When in use, the cap 60 is removed by the user before injection, for example, by simply holding the barrel 30 with one hand and pulling it out with the other hand. Before use of this syringe 1 with a safety device, the cap 60 is attached to the syringe 10 as shown in FIG. 1. When in use, the cap 60 is removed.

[0072] Hereinafter, the steps of assembling the safety syringe 1 of the first embodiment will be described with reference to FIGS. 5A to 5D.

[0073] In the process of assembling the syringe 1 with a safety device, first, as shown in FIG. 5A, the ejector 40 is attached from the rear end of the inner cylinder 20. In this case, the pair of release protrusions 41 of the ejector 40 are inserted into the ejector passage groove 25 of the inner cylinder 20, and the inner cylinder release parts 21b of the pair of release protrusions 41 are engaged with the inner cylinder 20. Next, the spring member 50 is inserted into the inner cylinder 20 from the tip side of the inner cylinder 20. Next, as shown in FIG. 5B, the inner cylinder 20 with the spring member 50 inserted therein is inserted from the large diameter part 31 side to the medium diameter part 32 of the outer cylinder 30, and the spring member 50 is compressed, so that the inner cylinder release parts 21b of the pair of inner cylinder swinging pieces 21 are fitted into the inner cylinder swinging piece fitting groove 32b of the outer cylinder 30, and the inner cylinder 20 is fixed to the outer cylinder 30. In this step, when the inner cylinder 20 is inserted into the large diameter portion 31 of the outer cylinder 30, the inner cylinder 20 is inserted into the large diameter portion 31 while pressing the pair of return prevention pieces 22 toward the center.

[0074] 5C, the syringe 10 filled with the drug solution is inserted from the rear end side of the inner cylinder 20, and the barrel flange portion 11a of the barrel 11 is fitted into the inner cylinder locking portion 21c at the rear end of the inner cylinder 20. In this case, the tip of the puncture needle 15 (cap 60) is exposed from the tip of the small diameter portion 33 of the outer cylinder 30. The drug solution in the syringe 10 is sealed by the gasket 12. With this structure, the syringe filled with the drug solution can be incorporated into the safety device after the safety device is assembled.

[0075] Most Then, as shown in Fig. 5D, the plunger rod 13 is inserted from the rear end of the barrel 11 and screwed into the gasket 12. This completes the assembly of the syringe 1 with a safety device, as shown in Fig. 1a. In this manner, the syringe 1 with a safety device can be easily assembled.

[0076] Next, the operational state during use of the safety syringe 1 of the first embodiment will be described with reference to Figs.

[0077] Fig. 6 is a cross-sectional view showing a state in which the plunger flange portion 14 is pressed, the ejector 40 is actuated, and the inner cylinder release portion 21b of the inner cylinder swing piece 21 of the inner cylinder is released in operation of the syringe with a safety device 1 of the first embodiment, and Fig. 7 is a cross-sectional perspective view showing a locked state when the inner cylinder 20 and the syringe 10 move backward in operation of the syringe with a safety device 1 of the first embodiment. Here, Fig. 6 is a vertical cross section taken along a plane along the axis, and Fig. 7 is a horizontal cross section taken along a plane along the axis.

[0078] When using (injecting) the syringe 1 with a safety device of the first embodiment, first, the cap 60 is removed. Next, after the user punctures a predetermined injection site, the drug solution in the syringe 10 is injected by pressing the plunger flange portion 14 provided on the rear end side of the plunger rod 13, thereby performing the injection.

[0079] When the injection is completed, as shown in Fig. 6, the plunger flange portion 14 comes into contact with the rear end of the ejector 40. When the plunger flange portion 14 is further pressed in this state, the ejector 40 is pushed, and the pair of release protrusions 41 on the tip side of the ejector 40 press the inclined surface 21a of the inner cylinder 20, causing the pair of inner cylinder swing pieces 21 to deform radially inward, i.e., to bend, so that the inner cylinder release portions 21b of the pair of inner cylinder swing pieces 21 move from the engaged position to the disengaged position.

[0080] As a result, the fixation between the inner cylinder 20 and the outer cylinder 30 is released, and the syringe 10, the inner cylinder 20, and the ejector 40, which are attached integrally, move backward relative to the outer cylinder 30 due to the biasing force of the spring member 50, so that the puncture needle 15 retracts into the small diameter portion 33 of the outer cylinder 30 (see Figs. 1b, 4A, and 4B). In this case, the pair of return prevention pieces 22 of the inner cylinder 20 protrude from the rear end of the outer cylinder 30 from the state in which they are housed inside the large diameter portion 31 of the outer cylinder 30 (see Fig. 3B), and the tip portions thereof widen (see Fig. 4b). When the inner cylinder 20 tries to return to the tip side, as shown in Fig. 7, the pair of return prevention pieces 22 of the inner cylinder 20 abut against the rear end of the large diameter portion 31 of the outer cylinder 30, preventing the inner cylinder 20 from returning to the tip side. At the same time, the pair of anti-slip pieces 23 of the inner cylinder 20 are hooked to the outer cylinder locking portion 34a between the large diameter portion 31 and the medium diameter portion 32 of the outer cylinder 30, preventing the inner cylinder 20 from being pulled out of the outer cylinder 30. This makes it possible to reliably prevent punctures by the puncture needle 15 after use and to re-use the syringe 1.

[0081] Next, the effects of the syringe with safety device 1 according to the first embodiment and the syringe safety device 2 attached to the syringe will be described.

[0082] In the syringe 1 with a safety device of the first embodiment, after the injection is completed, the pair of inner cylinder swing pieces 21 of the inner cylinder 20 are bent inward by pressing the ejector 40 with the plunger flange portion 14, and the fixation between the inner cylinder 20 and the outer cylinder 30 can be released. This allows the puncture needle 15 to be fully retracted after use of the syringe 1, and effectively prevents punctures by the puncture needle 15 and reuse of the syringe 1. In addition, this safety device 2 can be easily attached to an existing syringe 10 (syringe). In addition, the safety device 2 has a shorter overall length than a general one due to an improved internal structure, which leads to a reduction in the amount of waste.

[0083] More specifically, in the first embodiment, when the ejector 40 is pushed forward via the plunger, the tip (ejector release portion 41a) of the release piece 41 of the ejector 40 can push the inner cylinder release portion 21b down toward the axis. In particular, the ejector release portion 41a is formed in a right-angled triangular shape that bulges toward the axis and has a slope on the front side, and the inner cylinder release portion 21b is formed in a right-angled triangular shape that bulges away from the axis and has a slope on the rear side, so that when the ejector 40 is displaced forward, the inner cylinder release portion 21b can be pushed down while sliding toward the axis due to the slopes.

[0084] Incidentally, since the inner cylinder release portion 21b is provided on the inner cylinder swinging piece 21 which can swing up and down, when the inner cylinder release portion 21b is pushed down, the inner cylinder swinging piece 21 on which it is provided is pushed down as well. And since the inner cylinder locking portion 21c is also provided on this inner cylinder swinging piece 21, in short, pushing down the inner cylinder release portion 21b means pushing down the inner cylinder swinging piece 21 (with the inner cylinder release portion 21b and the inner cylinder locking portion 21c) as a whole. As a result, the inner cylinder locking portion 21c is separated from the outer cylinder locking portion 34a described above, and the locking by the locking means is released.

[0085] Therefore, according to the syringe 1 with a safety device of the first embodiment, the locking is released directly by the ejector 40, so that the locking of the locking means can be released more reliably.

[0086] In addition, in the first embodiment, the inner tube fixing portion, which expands in diameter at the rear end of the inner tube 20, is recessed in the front-to-rear direction to provide a groove portion 25 for the ejector to pass through, and the release piece 41 provided on the ejector 40 is thin-plate shaped and configured to slip through this groove portion 25 for the ejector to pass through.

[0087] In addition, the ejector release portion 41a provided at the tip of the release projection 41 bulges in the direction approaching the axis, but since this release projection 41 is configured to be able to swing up and down, when it is inserted into the ejector passing groove portion 25 of the inner tube 20, the ejector release portion 41a can be caused to climb over the ejector passing groove portion 25 of the inner tube 20 and positioned behind the inner tube release portion 21b by swinging it up and down.

[0088] Therefore, in the syringe with safety device 1 of the first embodiment, there is no need to design the ejector 40 to have a larger diameter than the inner cylinder fixing portion 20b, and therefore there is no need to design the outer cylinder 30 that fits around this ejector 40 to have a larger diameter either, so that the thickness can be reduced to make the syringe smaller.

[0089] Furthermore, in the first embodiment, when the fixation between the inner tube 20 and the outer tube 30 is released and the rear end of the inner tube 20 comes out of the outer tube 30, the return prevention piece 22 of the inner tube 20 spreads, preventing the inner tube 20 from returning to the tip side, and reliably preventing reuse of the syringe 1. In particular, since the return prevention piece 22 is formed with the return prevention end surface 22f that engages with the rear end of the outer tube 30, even if the inner tube 20 is advanced relative to the outer tube 30 to return the puncture needle 15 to the use position again, the return prevention end surface 22f of the inner tube 20 engages with the rear end of the outer tube 30, preventing the inner tube 20 from returning to the tip side, and reliably preventing reuse of the syringe 1.

[0090] In the first embodiment, the return prevention piece 22 can be stored in the outer tube 30 at the use position by being elastically deformed and pushed down in a direction approaching the axis. Specifically, the return prevention piece 22 is provided in a thin plate shape extending forward from the tip surface of the inner tube fixing part 20b, so there is no need to make the diameter of the inner tube 20 thicker, and the inner tube 20 has a storage hole 27 for storing the return prevention piece 22 by cutting out a part of the cylindrical part that overlaps with the return prevention piece 22, so that a clearance is ensured for the return prevention piece 22 to swing without being significantly extended in a direction away from the axis.

[0091] Therefore, although the syringe with safety device 1 of the first embodiment is provided with the anti-return piece 22 that extends in the left-right direction, there is no need to thicken the outer cylinder 30, and therefore the thickness can be kept small to make the syringe smaller.

[0092] In addition, in the first embodiment, after use (after injection is completed), the fixation between the inner tube 20 and the outer tube 30 is released, and when the inner tube 20 moves backward relative to the outer tube 30, the slip-out prevention piece 23 of the inner tube 20 gets caught on the outer tube 30, preventing the inner tube 20 from slipping out of the outer tube 30. The protective shape can be reliably maintained.

[0093] In the first embodiment, the plunger flange portion 14 pushes the ejector 40 to release the fixation between the inner tube 20 and the outer tube 30, so there are few restrictions on the shape of the plunger flange portion 14, and it can be designed relatively freely. That is, the outer diameter of the plunger flange portion 14 is sufficient if it includes a portion that is equal to or larger than the inner diameter and smaller than the outer diameter of the ejector 40. In the first embodiment, the outer diameter of the tip side of the plunger flange portion 14 is approximately the same as or slightly smaller than the inner diameter of the ejector 40, and the outer diameter of the rear end side of the plunger flange portion 14 is equal to or larger than the inner diameter and smaller than the outer diameter of the ejector 40, so that after the syringe 1 is used, the plunger flange portion 14 is fitted and integrated with the ejector 40.

[0094] Furthermore, when made of a transparent or translucent material, the spring member 50 is positioned at the rear end side of the syringe 10 before use, so that the medicinal liquid can be seen from outside the outer tube 30 even after the syringe 10 is assembled into the outer tube 30.

[0095] Furthermore, in the first embodiment, the base end side of the cap 60 fits into and is attached to the tip of the outer tube 30. Therefore, when removing the cap 60 during use (injection), the tip of the outer tube 30 functions as a guide, allowing the cap 60 to be pulled out straight, reducing the risk of bending the puncture needle 15.

[0096] Therefore, according to the syringe 1 with a safety device of the first embodiment, the puncture needle 15 can be sufficiently retracted after use of the syringe 1, and it is possible to reliably prevent a puncture injury caused by the puncture needle 15 and reuse of the syringe 1. In addition, the safety device can be easily attached to an existing syringe 10.

[0097] A syringe with a safety device 1A and a syringe safety device 2A attached to the syringe according to a second embodiment of the present invention will be described below.

[0098] In the above-described syringe 1 with a safety device according to the first embodiment, the pair of return prevention pieces 22 has the main body 22a connected to the inner cylinder fixing part 20b of the inner cylinder 20, and the tip part 22b is formed wider in the radial direction than the main body 22a, but the present invention is not limited to this. For example, the pair of return prevention pieces 22 may be configured as shown in the following second embodiment.

[0099] 8 to 12 show the configuration of a safety syringe 1A according to a second embodiment of the present invention. FIG. 8 is an exploded perspective view showing the configuration of the safety syringe 1A. FIG. 9A shows a vertical cross section of the safety syringe 1A before use, and FIG. 9A shows a horizontal cross section of the safety syringe 1A before use. FIG. 10A shows a vertical cross section of the safety syringe 1A after use, and FIG. 10B shows a horizontal cross section of the safety syringe 1A after use. FIG. 11 is a locally enlarged cross section showing the state in which the return prevention piece 22A of the safety syringe 1A is in the stored position, and FIG. 12 is a locally enlarged cross section showing the state in which the return prevention piece 22A of the safety syringe 1A is in the return prevention position. Here, Figs. 9A and 10A are longitudinal cross sections taken along a plane (up-down plane) along the axis, and Figs. 9A, 10A, 11 and 12 are transverse cross sections taken along a plane (left-right plane) along the axis.

[0100] As shown in Fig. 8 to Fig. 12, the syringe with a safety device 1A includes a syringe 10, an inner cylinder 20A, an outer cylinder 30A, an ejector 40A, a spring member 50, and a cap 60. This syringe with a safety device 1A has almost the same configuration as the syringe with a safety device 1 according to the above-mentioned embodiment, except for the pair of return prevention pieces 22A and the fitting portion between the outer cylinder 30A and the ejector 40A, and therefore a detailed description thereof will be omitted. In this embodiment, the syringe safety device 2A includes the inner cylinder 20A, the outer cylinder 30A, the ejector 40A, and the spring member 50.

[0101] The inner cylinder 20A is formed into a hollow cylindrical shape from, for example, a resin material, and is composed of an inner cylinder main body portion 20a on the front end side and an inner cylinder fixing portion 20b on the rear end side. The inner cylinder main body portion 20a on the front end side is connected to the medium diameter portion 32A of the outer cylinder 30A. and the inner cylinder fixing portion 20b on the rear end side is formed so as to be insertable into the large diameter portion 31A of the outer cylinder 30A.

[0102] A pair of inner cylinder swing pieces 21A are provided at a position close to the rear end side of the inner cylinder main body 20a of the inner cylinder 20A. The pair of inner cylinder swing pieces 21A are formed by providing a C-shaped slit s (corresponding to the "first inner cylinder groove" in this embodiment) in the side wall of the inner cylinder 20A. In addition, each of the pair of inner cylinder swing pieces 21A is provided with an inner cylinder release part 21b having an inclined surface 21a that abuts against the ejector 40A at the tip, and an inner cylinder locking part 21c for fitting into the inner cylinder swing piece fitting groove 32b of the outer cylinder 30A is provided on the outer peripheral surface. In addition, a thin wall part 21d for bending and deforming when operating is provided on the outer peripheral surface of the base. The pair of inner cylinder swing pieces 21A of the inner cylinder 20A are formed elastically deformable so that the inner cylinder locking part 21c is displaced between an engagement position and a disengagement position to perform the function of releasing the fixation between the inner cylinder 20A and the outer cylinder 30A. In addition, a hollow portion 21e for preventing sink marks on the resin molded product is provided in the center of the inner cylinder releasing portion 21b.

[0103] In addition, a pair of return prevention pieces 22A are provided at the rear end side of the inner cylinder main body 20a of the inner cylinder 20A at a position rotated 90 degrees relative to the pair of inner cylinder swing pieces 21A. The support portion 22c of the main body portion 22B of the pair of return prevention pieces 22A is connected to the upper portion of the swing connection piece 22d formed on the outer circumferential surface of the rear end side wall of the inner cylinder 20A, and the tip portion 22e is formed wider in the radial direction than the support portion 22c. Since a gap g is provided between the swing connection piece 22d and the inner cylinder fixing portion 20b of the inner cylinder 20A, the swing connection piece 22d can be flexibly deformed toward the tip side, and the tip portion 22e of the pair of return prevention pieces 22A can be displaced in the radial direction and can be stored in the outer cylinder 30A. In addition, the support portion 22c is formed to abut against the inner cylinder fixing portion 20b of the inner cylinder 20A. The tip end surface of the tip portion 22e is formed with a return prevention end surface 22f that fits into the rear end of the large diameter portion 31A of the outer tube 30A. By providing this return prevention end surface 22f, the edge of the outer tube 30A is guided into the return prevention end surface 22f of the return prevention piece 22A, making it easier to catch the edge of the outer tube 30A and to easily lock it. In addition, the outer periphery of the tip portion 22e of the pair of return prevention pieces 22A is formed so that it can be fitted into the opening 31b of the outer tube 30A. The pair of return prevention pieces 22A can be elastically deformed by bending in the radial direction so as to be displaced between a storage position stored in the outer tube 30A and a return prevention position extending out from the outer tube 30A. That is, the pair of return prevention pieces 22A are configured so that the outer peripheral surface 22g does not come into contact with the large diameter portion 31A of the outer tube 30A in the stored position, and when the support portion 22c of the inner tube 20A comes out of the outer tube 30A, it expands in the radial direction from the stored state, and the return prevention end surface 22f comes into contact with and engages with the rear end of the large diameter portion 31A of the outer tube 30A, thereby preventing the inner tube 20A from returning to the tip side. The inner tube 20A has a notch in the cylindrical portion overlapping with the return prevention piece 22A, and this notch becomes the storage hole portion 27A in which the return prevention piece 22A is stored when it swings in the direction approaching the axis. In addition, a lightening portion 22h for preventing sink marks in the resin molded product is provided on both sides of the main body portion 22B of the return prevention piece 22A.

[0104] A pair of anti-slip pieces 23A is provided on the tip side of the inner tube 20A (i.e., at a position axially distant from the return prevention piece 22A), and anti-slip protrusions 23a are provided on the outer peripheral surfaces of the tip sides of the pair of anti-slip pieces 23A. The pair of anti-slip pieces 23A are configured such that, when the support portion 22c of the inner tube 20A comes out of the outer tube 30A, the anti-slip protrusions 23a slide along a pair of slits 32a of the outer tube 30A and engage with the outer tube locking portion 34a between the large diameter portion 31A and the medium diameter portion 32A of the outer tube 30A, thereby preventing the inner tube 20A from coming out of the outer tube 30A.

[0105] Also, a fitting portion 24A for fitting the barrel flange portion 11A of the barrel 11 and an ejector passing groove portion 25A for passing a pair of release protrusions 41A of the ejector 40A are provided on the rear end side of the inner cylinder 20A. Furthermore, a plurality of ribs 26A for restricting the rear end of the spring member 50 are provided on the rear end side of the inner peripheral surface of the inner cylinder 20A. The barrel 11 is fixed to the inner cylinder 20A by the fitting portion 24A. As a result, when the engagement of the pair of inner cylinder swing pieces 21A is released, the barrel 11 moves together with the inner cylinder 20A.

[0106] The outer cylinder 30A is formed of, for example, a resin material, with a large diameter section 31A, a medium diameter section 32A, and a small diameter section 33A integrally formed into a three-stage hollow cylinder. In the outer cylinder 30A, the large diameter section 31A is formed into a substantially elliptical cylindrical shape, and the rear end of the inner cylinder 20A and the ejector 40A can be stored inside this large diameter section 31A. A slope 31c is formed on the rear end surface of the large diameter section 31A. In addition, a pair of ribs 31d extending in the axial direction are formed at opposing positions on the inner peripheral surface of the large diameter section 31A. Furthermore, a pair of openings 31b are provided on the tip side of the large diameter section 31A and at a position rotated 90 degrees relative to the pair of ribs 31d.

[0107] In the outer tube 30A, the medium diameter section 32A and the small diameter section 33A are each formed in a cylindrical shape. The medium diameter section 32A is formed so that the inner tube main body 20a at the tip side of the inner tube 20A can be inserted inside the medium diameter section 32A, and a pair of slits 32a extending in the axial direction are provided at a position facing the side wall of the medium diameter section 32A. The tips of the pair of slits 32a are partially extended to the small diameter section 33A. In addition, a pair of inner tube swing piece fitting grooves 32b for fitting the inner tube release parts 21b of the pair of inner tube swing pieces 21A of the inner tube 20A are provided at a position rotated 90 degrees from the pair of slits 32a on the rear end side wall of the medium diameter section 32A. Furthermore, a flange section 34A is provided between the large diameter section 31A and the medium diameter section 32A so that the user can hold it. The flange portion 34A is a portion on which, for example, the index finger and middle finger are placed when the user presses the plunger flange portion 14 with the thumb. A substantially ring-shaped protrusion 32c having the same inner diameter as the small diameter portion 33A is provided on the inside of the connecting portion between the medium diameter portion 32A and the small diameter portion 33A of the outer tube 30A. This allows the spring member 50 to be stably held in the center of the shaft without misalignment.

[0108] The ejector 40A is formed, for example, from a resin material in a substantially elliptical short cylinder shape. A pair of release protrusions 41A is provided on the tip side of the ejector 40A. The pair of release protrusions 41A are configured so that, after the injection is completed, the ejector 40A is pushed by the plunger flange portion 14, and the pair of inner cylinder swinging pieces 21A of the inner cylinder 20A are pushed and bent. In addition, grooves 42A extending in the axial direction are formed on the outer peripheral surface of the pair of release protrusions 41A. The pair of grooves 42A are formed so as to be able to fit into a pair of ribs 31d extending in the axial direction formed on the inner peripheral surface of the large diameter portion 31A of the outer cylinder 30A, and define the circumferential position of the ejector 40A and guide the sliding of the ejector 40A. In addition, a pair of notches 43A are provided on the rear end edge portion of the ejector 40A.

[0109] The process of assembling the safety syringe 1A of the second embodiment has the same procedures as those for the safety syringe 1 of the first embodiment described above, and therefore detailed description thereof will be omitted.

[0110] Next, the operational state during use of the safety syringe 1A of the second embodiment will be described with reference to Figs. 9A to 12.

[0111] When using the syringe 1A with a safety device (for injection), first, the cap 60 is removed. Next, similarly to the first embodiment described above, the user punctures a predetermined injection site, and then presses the plunger flange portion 14 provided on the rear end side of the plunger rod 13 to inject the medicinal liquid in the syringe 10 and perform the injection. When the injection is completed, the plunger flange portion 14 comes into contact with the rear end of the ejector 40A.

[0112] If the plunger flange portion 14 is pressed further in this state, the ejector 40A is pushed, and the pair of release protrusions 41A at the tip side of the ejector 40A push and bend the pair of inner tube oscillating pieces 21A of the inner tube 20A, so that the pair of inner tube oscillating pieces 21A move into the engaged position and the disengaged position (as in the first embodiment described above, see Figure 6).

[0113] This releases the fixation between the inner tube 20A and the outer tube 30A, and the syringe 10, inner tube 20A and ejector 40A, which are fixed together, move backward relative to the outer tube 30A, and the puncture needle 15 retracts inside the small diameter portion 33A of the outer tube 30A (see Figures 10A and 10B).

[0114] In this case, the pair of anti-return pieces 22A of the inner tube 20A move from being stored inside the large diameter portion 31A of the outer tube 30A (see Figure 11) to extending out from the rear end of the outer tube 30A (see Figure 10B). At the same time, the pair of anti-slip pieces 23A of the inner tube 20A hook onto the outer tube engaging portion 34a located between the large diameter portion 31A and the medium diameter portion 32A of the outer tube 30A, preventing the inner tube 20A from coming off the outer tube 30A.

[0115] In addition, when the inner cylinder 20A tries to return to the tip side, as shown in Fig. 12, the return prevention end faces 22f of the pair of return prevention pieces 22A come into contact with the inclined faces 31c of the rear end faces of the large diameter parts 31A of the outer cylinder 30A, preventing the inner cylinder 20A from returning to the tip side. This can reliably prevent punctures by the puncture needle 15 and reuse of the syringe 1A.

[0116] The syringe with a safety device 1A and the syringe safety device 2A of the second embodiment can obtain the same effects as those of the syringe with a safety device 1 and the syringe safety device 2 of the first embodiment described above.

[0117] In the second embodiment, the inner tube 20A is provided with a pair of return prevention pieces 22A having a return prevention end face 22f concave toward the rear on the tip surface, which allows easy locking and reliably prevents the inner tube 20A from returning to the tip side. Note that, since this design change of the concaves and convexes is made in the front-rear direction, there is no need to increase the diameter of the inner tube 20A and the outer tube 30A.

[0118] In the second embodiment, the pair of return prevention pieces 22A are formed so that the main body 22B is connected to the upper part of the swing connection piece 22d, and the support part 22c abuts against the inner tube fixing part 20b of the inner tube 20A. Therefore, even if the inner tube 20A is moved forward relative to the outer tube 30A after use, the main body 22B that hits the rear end of the outer tube 30A is not displaced backward, and further forward movement is prevented.

[0119] Similarly, in the second embodiment, the main body portion 22B is formed into a strong rectangular parallelepiped shape, so that even if it is sandwiched between the rear end of the outer tube 30A and the front end of the inner tube fixing portion 20b and a crushing load is applied in the front-to-rear direction, unintended deformation is unlikely to occur.

[0120] Therefore, according to the safety syringe 1A of the second embodiment, it is possible to further prevent reuse of the syringe 1A that has been used once, and to prevent accidental contact with the puncture needle 15 after use.

[0121] More specifically, in the second embodiment, the main body 22B is hollowed out from a rectangular parallelepiped shape, thereby preventing the occurrence of sink marks and voids, and a plate-shaped portion extending in the up-down and left-right directions including the return prevention end face 22f remains on the front side, and a plate-shaped portion extending in the up-down and left-right directions including the support portion remains on the rear side, and further, the two plate-shaped portions connecting the two are cut out so that the plate-shaped portion extending in the front-to-back and up-down directions and the plate-shaped portion extending in the front-to-back and left-right directions intersect and extend, thereby minimizing the reduction in strength.

[0122] Furthermore, in the syringe with safety device 1A, the pair of anti-return pieces 22A are configured so that, when in the stored position, the outer peripheral surface 22g does not come into contact with the wall of the large diameter portion 31A of the outer barrel 30A, thereby preventing malfunctions due to changes over time in the stored state.

[0123] Below, we will explain the syringe with safety device 1 according to the third embodiment of the present invention, the syringe safety device 2 attached to the syringe, the syringe with safety device 1A, and the finger clip 70 attached to the syringe safety device 2A attached to the syringe (hereinafter, only the syringe with safety device 1 will be referred to as a representative of these).

[0124] 13 to 17 show the configuration of the finger clip 70 of this embodiment. FIG. 13 is a front view showing the configuration of the finger clip 70, and FIG. 14 is a plan view showing the configuration of the finger clip 70. 15 is a cross-sectional view taken along the line CC in FIG. 14 , FIG. 16 is a front view showing how a finger clip 70 is attached to the syringe with a safety device 1, and FIG. 17 is a rear perspective view showing the syringe with a safety device 1 with the finger clip 70 attached.

[0125] 13 is defined as the upper and lower sides of the finger clip 70. The upper side is the proximal end side where the plunger rod 13 and the plunger flange portion 14 are arranged, and the lower side is the distal end side where the puncture needle 15 and the cap 60 are arranged.

[0126] As shown in Figures 13 and 14, the finger clip 70 of this embodiment has an outer shape that resembles an arch when viewed from the front and an ellipse when viewed from above, and has a through hole in the center through which the syringe 1 with a safety device is inserted.

[0127] Finger clip 70 is formed of finger flanges that jut out like wings on both ends of the long axis side of an ellipse when viewed from above, and a central body portion having a through hole. Finger flange bottom portion 74 and body bottom portion 76 that form the bottom surface are formed on the finger flange and body portion, respectively. The outer bottom surface formed by finger flange bottom portion 74 and body bottom portion 76 is where the user's fingers, such as the index finger and middle finger, are hooked when finger clip 70 is used.

[0128] A plurality of, for example, three, horizontal ribs 74a are formed on each of the pair of finger flange bottoms 74 in the short direction of the finger clip 70, so that the fingers are less likely to slip even when force is applied during use.

[0129] A mounting cylindrical portion 72 is formed around the barrel through-hole so as to extend downward from the underside of the barrel bottom portion 76. An inner peripheral surface 721 of the mounting cylindrical portion 72 is a portion that comes into contact with the outer peripheral surface of the medium diameter portion 32 of the outer barrel 30 when the mounting cylindrical portion 72 is mounted on the safety-equipped syringe 1. As shown in Figures 14 and 15, a pair of relief recesses 722 are formed on the inner peripheral surface 721 of the mounting cylindrical portion 72 to avoid interference with the slip-out prevention protrusions 23a.

[0130] A barrel reinforcing rib 75 is provided on the barrel so as to extend upward from the barrel bottom 76. The barrel reinforcing rib 75 is composed of a linear wall rib 75b forming the barrel side surface and an annular rib 75a provided so as to surround the outer periphery of the mounting cylindrical portion 72. The flange portion 34 of the syringe 1 with a safety device is housed and mounted in a barrel internal space 77 formed by the wall rib 75b and the annular rib 75a.

[0131] For this reason, the size of the ellipse bordered by the inner surfaces of the wall rib 75b and the annular rib 75a corresponds to the outer periphery of the flange portion 34, but the inner surface of the annular rib 75a is slightly larger, and the wall rib 75b is positioned away from the flange portion 34 by the size (height) of the guide rib 752 described later.

[0132] A bottom reinforcement rib 73c having an L-shape in plan view is formed on the body bottom 76, extending from the annular rib 75a to the mounting cylindrical portion 72 around the through hole. One end of the bottom reinforcement rib 73c is connected to the joint between the wall rib 75b and the annular rib 75a, and the other end is connected shifted from the center of the annular rib 75a toward the wall rib 75b to which the one end is connected.

[0133] On the inner peripheral surface of the annular rib 75a, a pair of rib fitting protrusions 751 for contacting and fixing to the base end side surface of the flange portion 34 of the stored syringe with safety device 1 are formed on each of the left and right annular ribs 75a in an upper and lower direction. On the wall rib 75b, a pair of guide ribs 752 for guiding the flat portion 34d of the flange portion 34 is formed on each of the wall ribs 75b in the upper and lower direction.

[0134] The flange portion 34 of the safety syringe 1 is housed and attached in the barrel internal space 77, with the lower surface (tip side surface) of the flange portion 34 abutting against the bottom reinforcing rib 73c and the outer periphery of the upper surface (base side surface) being located below the fitting convex portion 751. In other words, the flange portion 34 is sandwiched between the bottom reinforcing rib 73c and the fitting convex portion 751.

[0135] A pair of flange reinforcement ribs 73b extend from the points where the bottom reinforcement rib 73c of the annular rib 75a is joined toward the left and right ends, and follow the outer shape of the finger flanges while narrowing the gap therebetween.

[0136] A finger flange rib 73a is formed on the outer periphery of the finger flange and is connected to the wall rib 75b. A V-shaped flange reinforcement rib 73b extends from the middle of the finger flange rib 73a with a slight gap between them and is connected to the finger flange rib 73a.

[0137] Since the upper portion and base end side of the finger clip 70 are constituted by the above-mentioned ribs, shrinkage caused by the thickness of the material is prevented.

[0138] Next, a method for attaching the finger clip 70 of this embodiment to the safety syringe 1 will be described.

[0139] First, as shown in FIG. 15, the upper base end side of the finger clip 70 is placed opposite the tip end side of the safety syringe 1.

[0140] Next, the finger clip 70 is moved so as to slide on the barrel 30 toward the base end side of the safety syringe 1. At this time, the barrel 30 enters the barrel through-hole via the barrel internal space 77.

[0141] When the finger clip 70 is further moved toward the base end, the flange 34 enters the body internal space 77, climbs over the fitting protrusion 751, and comes into contact with the bottom reinforcing rib 73c.

[0142] As a result, the finger clip 70 is fixed to the safety syringe 1, resulting in the state shown in FIG.

[0143] Next, a modification of the finger clip 70 of this embodiment will be described.

[0144] In the above embodiment, an example was shown and described in which four mating protrusions 751 are evenly arranged, but the present invention is not limited to this, and any number of two or more may be formed, and may be continuous in a ring shape.

[0145] In the above embodiment, an example in which the guide ribs 752 are formed in four locations has been described, but the present invention is not limited to this, and any number of guide ribs may be formed as long as it is two or more locations.

[0146] In the above-described embodiment, the large diameter portions 31 and 31A of the outer cylinders 30 and 30A are formed in a substantially elliptical cylindrical shape, but the present invention is not limited to this. For example, they may be formed in a cylindrical shape.

[0147] The present invention is not limited to the above-described embodiments, and its technical scope includes various modified forms of design within the scope that does not deviate from the gist of the invention described in the claims. [Explanation of symbols]

[0148] 1, 1A Syringe with safety device 2, 2A Syringe safety device 10 Syringe 11 Barrel 12 Gasket 13 Plunger rod 14 Plunger flange portion 15 Puncture needle 20, 20A Inner tube 20a Inner tube main body portion 20b Inner tube fixing portion 21, 21A Inner tube swing piece 21a Inclined surface 21b Inner tube release portion 21c Inner tube locking portion 21d Thin portion 21e, 22h Lightening portion 22, 22A Return prevention piece 22B Main body portion 22a Main body portion 22b Tip portion 22c Support portion 22d Swing connection piece 22e Tip portion 22f Return prevention end surface 22g Outer circumferential surface 23, 23A Pull-out prevention piece 23a Pull-out prevention protrusion 24, 24A Fitting portion 25, 25A Ejector passage groove portion 26, 26A Spring abutment rib 27, 27A Storage hole portion 30, 30A Outer cylinder 31, 31A Large diameter portion 31a Groove 31b Opening 31c Slope 31d Rib 32, 32A Medium diameter portion 32a Slit 32b Inner cylinder swing piece fitting groove 32c Protrusion 33, 33A Small diameter portion 34, 34A Flange portion 34a Outer cylinder locking portion 34b Step portion 40, 40A Ejector 41, 41A Release protrusion 41a Ejector release portion 42 Rib 42a Groove 43a Cutout portion 50 Spring member 60 Cap 70 Finger clip g Gap s Slit

Claims

1. a syringe safety device attached to a syringe including: a barrel having a puncture needle at a front end and a barrel flange portion at a rear end, the barrel containing a medicinal solution; and a plunger whose front end is slidably inserted from the rear end side of the barrel and has a plunger flange portion at its rear end, wherein when a direction along the axis of the puncture needle is defined as a front-rear direction, a first direction perpendicular to the front-rear direction is defined as a top-bottom direction, and a second direction perpendicular to the front-rear direction and the top-bottom direction is defined as a left-right direction, the syringe safety device comprises: an inner tube which is cylindrical and fitted to the outside of the barrel, and fixed to the barrel flange portion; an outer tube which is cylindrical and fitted to the outside of the barrel and the inner tube, and is capable of storing the puncture needle, and is slidable along the outer circumferential surface of the barrel; a spring member built into the outer tube, and which urges the inner tube rearward relative to the outer tube; and a locking means which locks the inner tube in a use position where the puncture needle protrudes from the front end of the outer tube against the urging force of the spring member; and an ejector having a cylindrical shape that is fitted inside the outer barrel and releases the locking by the locking means, the inner barrel having an inner barrel fixing portion provided at its rear end and fitted onto the outside of the barrel flange portion, the inner barrel fixing portion having an ejector passing groove portion that is recessed from the front end to the rear end of the inner barrel fixing portion in a direction approaching the axis, the ejector having a release projection that extends forward from an end in the vertical direction of the front end and can pass through the ejector passing groove portion, and the locking means is configured to be releasable by a front end of the release projection of the ejector that is pushed forward via the plunger flange portion of the plunger when the plunger is displaced forward.

2. a syringe safety device attached to a syringe including: a barrel having a puncture needle at a front end and a barrel flange portion at a rear end, the barrel containing a medicinal solution; and a plunger whose front end is slidably inserted from the rear end side of the barrel and has a plunger flange portion at its rear end, wherein when a direction along the axis of the puncture needle is defined as a front-rear direction, a first direction perpendicular to the front-rear direction is defined as a top-bottom direction, and a second direction perpendicular to the front-rear direction and the top-bottom direction is defined as a left-right direction, the syringe safety device comprises: an inner tube which is cylindrical and fitted to the outside of the barrel, and fixed to the barrel flange portion; an outer tube which is cylindrical and fitted to the outside of the barrel and the inner tube, and is capable of storing the puncture needle, and is slidable along the outer circumferential surface of the barrel; a spring member built into the outer tube, and which urges the inner tube rearward relative to the outer tube; and a locking means which locks the inner tube in a use position where the puncture needle protrudes from the front end of the outer tube against the urging force of the spring member; and an ejector having a cylindrical shape that is fitted inside the outer tube and releases the locking by the locking means, the inner tube having a cylindrical inner tube main body portion, and an inner tube fixing portion that is connected to the rear end of the inner tube main body portion via an inner tube step portion, has a cylindrical shape with an outer diameter larger than that of the inner tube main body portion, and is fitted to the outside of the barrel flange portion, the inner tube main body portion having a U-shaped first inner tube groove portion that is adjacent to the inner tube step portion and extends along the front-rear direction when viewed along the vertical direction and is open on the front side, an inner tube swinging piece that is surrounded by the first inner tube groove portion and can swing in the vertical direction, an inner tube releasing portion provided at the rear end of the inner tube swinging piece, and an inner tube locking portion that is provided adjacent to the front side of the inner tube releasing portion of the inner tube swinging piece with a gap therebetween and bulges in the direction away from the axis along the vertical direction, the inner cylinder fixing portion is provided at a position adjacent to the inner cylinder swinging piece, and has an ejector passing groove portion recessed from the front end to the rear end of the inner cylinder fixing portion in a direction approaching the axis; the ejector has a release protrusion extending forward from the vertical end of the front end and narrower and thinner than the ejector passing groove portion, and an ejector release portion provided at the front end of the release protrusion; the outer cylinder has an outer cylinder locking portion extending from the vertical end of its inner circumferential surface in a direction approaching the axis, and disposed in a gap between the inner cylinder locking portion and the inner cylinder releasing portion in the use position; and the locking means isa release piece of the ejector being inserted into the ejector passage groove of the inner cylinder from the rear side so that the ejector release portion is positioned behind the inner cylinder release portion, and then the outer cylinder is fitted outward from the front side of the inner cylinder so that the rear end of the inner cylinder locking portion engages with the front end of the outer cylinder locking portion, thereby allowing the syringe to be locked at the usage position; and when the plunger is displaced forward, the ejector release portion of the ejector being pushed forward via the plunger flange portion of the plunger displaces the inner cylinder release portion toward the axis, thereby causing the inner cylinder swinging piece to swing and the inner cylinder locking portion provided on the inner cylinder swinging piece to move away from the outer cylinder locking portion, thereby allowing the lock to be released.

3. 3. The syringe safety device according to claim 2, wherein the release piece is configured to be swingable in the vertical direction, and the ejector release portion is formed in a convex shape that bulges in the vertical direction toward the axis and has a slope on its front side, and when the release piece of the ejector is inserted into the ejector passage groove of the inner cylinder, the release piece is caused to swing in the vertical direction so that it overcomes the ejector passage groove and is positioned at the rear of the inner cylinder release portion, and when the plunger is displaced forward, the slope on the front side is pushed forward and the inner cylinder release portion is pushed down while sliding toward the axis.

4. 3. The syringe safety device according to claim 2, wherein the inner tube has a return prevention piece that extends forward from a front left-right end of the inner tube fixing portion in a direction gradually moving away from the axis to a position that exceeds the inner diameter of the rear end of the outer tube, and is elastically deformable in the left-right direction, and a return prevention end face that is provided at the front end of the return prevention piece and engages with the rear end of the outer tube, wherein the return prevention piece is stored in the outer tube at the usage position by fitting the outer tube to the outside while pushing it down in a direction approaching the axis, and when the locking is released, the return prevention piece is displaced rearward relative to the outer tube to a position rearward beyond the rear end of the outer tube by the biasing force of the spring member.

5. 5. The syringe safety device according to claim 4, wherein the return prevention end surface is formed concavely toward the rear when viewed in the vertical direction, and the rear end of the outer cylinder is formed convexly toward the rear when viewed in the vertical direction at a position where it engages with the return prevention end surface, and is capable of being fitted with the return prevention end surface.

6. 6. The syringe safety device according to claim 4 or 5, wherein the anti-return piece is configured to be swingable in the left-right direction by being provided as a thin plate extending forward from a front end surface of the inner tube fixing portion, and the inner tube is provided by cutting out a cylindrical portion that overlaps with the anti-return piece when viewed along the left-right direction, and has a storage hole portion for storing the anti-return piece that has swung in a direction approaching the axis.

7. 6. The syringe safety device according to claim 4 or 5, wherein the anti-return piece comprises: a main body portion having the anti-return end face at a front end and spaced apart from an outer peripheral surface of the inner cylinder; a swinging connection piece extending from the left and right ends of the outer peripheral surface of the inner cylinder in a direction away from the axis along the left and right directions and connected to the main body portion, causing the main body portion to swing in the front-rear direction; and a support portion provided at a rear end of the main body portion and contacting a front end of the inner cylinder fixing portion to prevent the main body portion from swinging rearward.

8. The syringe safety device according to claim 7, wherein the main body portion has a rectangular parallelepiped shape extending along the front-rear, up-down and left-right directions.

9. 9. The syringe safety device according to claim 8, wherein the main body has a hollowed-out portion in a middle portion in a front-rear direction, the hollowed-out portion being cut out in only a part in a vertical direction and only a part in a horizontal direction.

10. A syringe with a safety device, comprising: the syringe; and the syringe safety device according to claim 9 attached to the syringe.

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