Liquid level observation assembly of syringe and syringe bracket
By designing the liquid level observation components of the tubular shell and bracket in the syringe, using sheath, slider and transparent window, combined with the elastic support arm and limit structure, the problems of poor liquid level observation effect and complex structure are solved, and the problem of poor liquid level observation effect and complex structure is achieved. Compact and stable syringe design.
Patent Information
- Application Number
- CN202323669169.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-30
- Publication Date
- 2025-01-03
- Estimated Expiration
- 2033-12-30
AI Technical Summary
In the existing syringe design, the liquid level observation effect is poor and the structure is complex, and the internal space is insufficient, resulting in problems such as unstable grip and increased installation steps.
Design a liquid level observation assembly including a tubular shell and a syringe cartridge bracket. By setting a sheath and slider between the shell and the bracket, the liquid level of the medicine is observed using transparent windows and inner and outer observation ports, combined with an elastic bracket Arm and limit structure ensure compact and stable structure.
It achieves good liquid level observation effect and structural compactness, reduces waste of internal space, and enhances the stability of use and installation convenience.
Smart Images
Figure CN222286113U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of injection equipment, and particularly relates to a liquid level observation component of a syringe and a syringe bracket. Background Art
[0002] The automatic injection pen can realize the automatic injection function of liquid medicine, such as insulin injection by patients, which can be completed with one hand, and is easy to use. In order to observe the liquid medicine in real time, some designs open holes in the shell, set special parts or matching parts inside to set transparent observation windows, which increases the radial size of the automatic injection pen, and the structure is more complicated, and the stability of use is reduced; some designs set transparent windows on the shell, but the transparent window is far away from the core, and the observation effect is not good; in some designs, there are also schemes that use circumferential orientation and multi-structure stacking to achieve dosage observation of the automatic injection pen, but the multiple stacking structures cause the internal space of the narrow automatic injection pen to be stacked in some parts and sparse in the rest of the parts, resulting in the overall structure being not coordinated, and its internal structure is not fully utilized, and the multi-layer stacking structure also causes the disadvantages of increasing the number of steps during installation.
[0003] The patent with the patent number CN115501426A discloses an injection pen and an injection method thereof, the injection pen comprises: an upper shell body, which defines an installation channel therein and is provided with a first through hole; a viewing window, which is provided with a second through hole, and one end of the viewing window is provided with a limit portion; a dose adjustment rod, a part of the dose adjustment rod forms a knob, the dose adjustment rod is provided with a matching portion, and the limit portion cooperates with the matching portion to limit the maximum rotation range of the dose adjustment rod; an injection button; a memory fixing rod; a rotating push rod, which is coaxially arranged in the memory fixing rod; a memory push rod, which is provided with an internal thread; an injection push rod, which is movably arranged in the memory push rod along its axial direction, and the injection push rod is provided with an external thread that matches the internal thread; an upper gear; a lower gear; a bracket, the bracket is connected to the upper shell body; a refill, the refill is arranged in the bracket, the refill is filled with injection liquid, and one end of the injection push rod extends into the bracket and stops with the refill.
[0004] The above-mentioned prior art achieves the effect of observing the core body by separately setting a window unit, which adds multiple components and has a relatively complex structure. It observes through the second through hole and the first through hole. Since there is a certain distance between the core body and the outer shell, the observation effect is not good.
[0005] Among other technical solutions known to the inventor, there is also a solution that adopts a circumferential orientation and a multi-structure stacking method to realize the dosage observation of the automatic injection pen. However, these multiple stacking structures to a certain extent cause the narrow internal space of the automatic injection pen to be transitionally stacked in some parts and transitionally sparse in other parts, resulting in an overall structural incoordination. Its internal structure is not fully utilized, and the multi-layer stacking structure also causes disadvantages such as an increase in the number of work steps during installation. Utility Model Content
[0006] The utility model aims to solve the above problems in the prior art and proposes a liquid level observation component for a syringe with a compact structure and good observation effect.
[0007] Another purpose of the utility model is to propose a syringe bracket to address the above problems in the prior art.
[0008] In order to achieve the purpose of innovation, the utility model can be achieved through the following technical solutions: a liquid level observation component of a syringe, comprising a tubular shell and a syringe holder arranged in the shell, a sheath is provided between the shell and the syringe holder, the sheath is engaged with the shell, the sheath is circumferentially provided with at least one axially arranged movable groove, the syringe holder is provided with a slider protruding from the bracket body, at least partially engaged with the movable groove and axially slidable in the movable groove, an inner observation port is provided on the syringe holder on the inner side of the slider, an outer observation port is provided on the shell outside the slider, and the slider is provided with a transparent window that enables the outer observation port to observe the amount of medicine in the syringe through the inner observation port.
[0009] A sheath is provided in the shell of the liquid level observation component of the syringe, and the syringe holder is clamped in the movable groove of the sheath through a slider to form a sliding connection. A through hole and an internal observation port are provided on the syringe holder on the inner side of the slider, and an external observation port is provided on the shell at a corresponding position. At the same time, a transparent window is provided on the slider. The overall structure is compact, and the liquid level of the medicine in the syringe in the syringe holder can be observed through the external observation port, the transparent window and the internal observation port.
[0010] In a more preferred liquid level observation assembly for a syringe, the sheath is provided with two axially arranged movable grooves along the circumference.
[0011] A strip-shaped movable groove is hollowed out on the cylindrical sleeve, one end of the movable groove is open and the other end is closed. The slider of the syringe holder is clamped in the movable groove. The syringe holder is slidably connected to the sleeve and can move axially relative to the sleeve while limiting relative rotation.
[0012] In a more preferred liquid level observation assembly for a syringe, the two movable grooves are evenly distributed in the circumferential direction.
[0013] There are two movable grooves, which are respectively arranged on both sides and are evenly distributed.
[0014] In a more preferred liquid level observation assembly of a syringe, the slider includes an upper protrusion and a lower protrusion, the inner ends of the upper protrusion and the lower protrusion are connected to the syringe holder, and the outer ends of the upper protrusion and the lower protrusion are connected to the transparent window, and an air passage is formed between the syringe holder, the upper protrusion, the lower protrusion and the transparent window.
[0015] The transparent window is connected to the syringe holder through an upper protrusion and a lower protrusion, forming an integrated structure. The upper protrusion and the lower protrusion extend radially on the syringe holder and are clamped in the movable groove, having a certain circumferential limiting effect. An air-separating channel is formed between the upper protrusion and the lower protrusion, and the internal situation can be observed through the transparent window and the air-separating channel.
[0016] As an optimization, the inner side of the transparent window is flat, and the outer side of the transparent window is arc-shaped. The transparent window utilizes the outer convex surface and the inner side is set to be flat to perform convex magnification. For some users with poor eyesight, this convex magnification function can enable them to see the internal structure more clearly.
[0017] In a more preferred liquid level observation assembly of a syringe, a plurality of limit rib groups distributed along the circumferential direction are provided between the sheath and the shell, the limit rib group includes a first limit rib axially arranged on the outer wall of the sheath, a second limit rib capable of cooperating with the first limit rib is provided on the inner wall of the shell, and the first limit rib and the second limit rib of two adjacent limit rib groups along the circumferential direction are symmetrical along the axial direction of the shell, and the movable groove is provided between two adjacent first limit ribs.
[0018] The two first limiting convex strips are located between the two second limiting convex strips, the first limiting convex strips and the second limiting convex strips cooperate to form a limit in the rotation direction, and the movable groove is arranged between the first limiting convex strips.
[0019] In a more preferred liquid level observation assembly of a syringe, the first limiting convex strip and / or the second limiting convex strip is provided with an axially arranged second step.
[0020] The second step functions similarly to a reinforcing rib, and enhances the structural strength of the connection position of the first limiting convex strip and / or the second limiting convex strip.
[0021] In a more preferred liquid level observation assembly for a syringe, an anti-slip step is provided at the inner end of the sheath, and a first step cooperating with the anti-slip step is provided on the second limiting convex strip.
[0022] The anti-slip step is located at the upper end of the sheath, and the anti-slip step abuts against the first step to form an axial limit between the sheath and the shell.
[0023] In a more preferred liquid level observation assembly for a syringe, a snap-fit structure which can be detachably fixed to the housing is provided at the lower end of the slider.
[0024] The buckle structure is used for the detachable fixed connection between the syringe bracket and the shell, and also has a certain axial and circumferential limiting function.
[0025] In a more preferred liquid level observation assembly for a syringe, the snap-fit structure comprises a snap hook disposed at the lower end of the slider, and a snap-fit groove and a snap-fit protrusion capable of cooperating with the snap hook are disposed on the inner wall of the shell.
[0026] The buckle hooks the buckling protrusion to form an axial limit, and the buckling groove has a yielding effect on the buckle hook. At the same time, a circumferential rotation limit is formed between the buckle hook and the side wall of the buckling groove.
[0027] In a more preferred liquid level observation assembly of a syringe, a stop protrusion is provided at the lower end of the hook, and a stop groove cooperating with the stop protrusion is provided on the lower step at the lower end of the shell.
[0028] The stop protrusion is used to engage with the snap-fit protrusion to achieve axial limitation. The stop groove is equivalent to the notch set on the lower step, which makes way for the stop protrusion and also has a certain rotational limiting effect. The lower end of the second limiting protrusion is connected to the lower step, and the two sides of the stop protrusion at the lower end of the hook can be against the lower steps on both sides of the stop groove, exerting an upward limiting support force in the axial direction.
[0029] In a more preferred liquid level observation assembly for a syringe, the body of the syringe holder is provided with an elastic support arm protruding inwardly for axially supporting and stabilizing the syringe body, and the elastic support arm is circumferentially eccentrically arranged relative to the slider.
[0030] A syringe holder comprises a tubular sleeve, the sleeve is provided with a syringe anti-dropping guide structure, the opening of the endmost edge of the syringe anti-dropping guide structure is larger than the opening slightly inward, so that it can play a guiding and anti-dropping role, and even if the syringe is not vertically installed, it can be easily installed in place through the syringe anti-dropping guide structure; when at least one inner observation port is opened in the circumferential direction on the sleeve, a slider connected to the sleeve is provided on the outer side of the inner observation port, and a transparent window is provided on the slider for observing the liquid level through the inner observation port, and the inner side surface of the transparent window is a plane, and the outer side surface is an arc shape.
[0031] A syringe is inserted and fixed in the barrel sleeve, and the syringe anti-falling guide structure forms a limiting effect on the syringe to prevent it from falling out from the inside. An internal observation port is provided on the barrel sleeve, and the liquid level of the medicine in the syringe can be observed through the transparent window on the slider through the internal observation port tube.
[0032] As an optimization, at least two axially arranged elastic support arms are evenly arranged circumferentially at the lower part of the barrel sleeve, and the lower end of the elastic support arm is provided with a positioning protrusion protruding inward. The positioning protrusion has a certain radial elasticity and can be elastically clamped with the outer wall of the lower part of the injection barrel to achieve the effect of stabilizing the barrel body of the injection barrel.
[0033] In the above-mentioned syringe bracket, the sliding block is provided with a hook capable of cooperating with the housing.
[0034] The hook is used to realize detachable connection and fixation with the shell.
[0035] Compared with the prior art, the utility model has the following advantages:
[0036] 1. The utility model provides a transparent window and an inner observation port on the syringe holder, and opens an outer observation port at a corresponding position on the shell. The liquid level of the medicine in the syringe holder can be observed through the outer observation port, the transparent window and the inner observation port. In particular, the transparent window has a convex magnification effect, so that the liquid in the syringe barrel can be better observed, and has good information interactivity. With such a design, the structure is compact, the observation area can be made larger, and the observation is convenient. At the same time, the overall structure is compact and small.
[0037] 2. The syringe holder is provided with an inwardly protruding elastic support arm, which is arranged circumferentially to better prevent the syringe from slipping, thereby making full use of the spatial structure and making the overall structure more compact.
[0038] 3. The space between the syringe holder and the sheath is reasonably utilized. The syringe holder cannot rotate circumferentially relative to the shell, nor can it slide axially relative to the shell. The syringe cannot slide or shake axially inside. The combination of various features makes reasonable use of space and realizes stable observation function. BRIEF DESCRIPTION OF THE DRAWINGS
[0039] Figure 1 It is a schematic diagram of the overall structure of the utility model;
[0040] Figure 2 It is a schematic cross-sectional view of the entirety of the utility model (the cross section passes through the transparent window);
[0041] Figure 3 It is a cross-sectional view of the housing of the utility model;
[0042] Figure 4 It is a structural schematic diagram of the syringe bracket of the utility model;
[0043] Figure 5 It is a schematic diagram of the cooperation between the syringe bracket and the sheath of the utility model;
[0044] Figure 6 It is a front view of the sheath of the utility model.
[0045] In the figure, the shell 1, the second limiting convex strip 11, the first step 12, the external observation port 13, the syringe bracket 2, the slider 21, the internal observation port 22, the transparent window 23, the barrel sleeve 24, the syringe anti-falling guide structure 25, the elastic support arm 26, the sheath 3, the movable groove 31, the first limiting convex strip 32, the second step 33, the anti-falling step 34, the buckle structure 4, the hook 41, the buckling groove 42, the buckling protrusion 43, the upper protrusion 44, the lower protrusion 45, the air-space channel 46, the stop protrusion 47, the lower step 48, and the stop groove 49. DETAILED DESCRIPTION
[0046] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.
[0047] Specific implementation examples Figure 1-6 As shown, the liquid level observation assembly of the syringe comprises a tubular outer shell 1 and a syringe holder 2 arranged in the outer shell 1, a sheath 3 is provided between the outer shell 1 and the syringe holder 2, and the sheath 3 is provided with at least one axially arranged movable groove 31 along the circumferential direction, a slider 21 which can slide axially with the movable groove 31 and is circumferentially limited is provided on the syringe holder 2, an inner observation port 22 is provided on the syringe holder 2 on the inner side of the slider 21, an outer observation port 13 is provided on the outer shell 1 on the outer side of the slider 21, and a transparent window 23 is provided on the slider 21 to enable the outer observation port 13 to observe the liquid level through the inner observation port 22.
[0048] Specifically, a sheath 3 is provided in the shell 1 of the liquid level observation assembly of the present syringe, and the syringe holder 2 is clamped in the movable groove 31 of the sheath 3 through the slider 21 to form a sliding connection, and an opening is provided on the syringe holder 2 on the inner side of the slider 21, and an internal observation port 22 is provided. An external observation port 13 is provided on the shell 1 at a corresponding position, and a transparent window 23 is provided on the slider 21. The liquid level of the medicine in the syringe in the syringe holder 2 can be observed through the external observation port 13, the transparent window 23 and the internal observation port 22.
[0049] like Figure 5 , 6 As shown, the sheath 3 is provided with two axially arranged movable grooves 31 along the circumferential direction, and the two movable grooves 31 are evenly distributed along the circumferential direction.
[0050] A strip-shaped active groove 31 is hollowed out on the cylindrical sheath 3. The active groove 31 is open at one end and closed at the other end. The slider 21 of the syringe holder 2 is clamped in the active groove 31. The syringe holder 2 is slidably connected to the sheath 3, and can move axially relative to each other while limiting relative rotation. The active groove 31 is provided with two respectively arranged on both sides, evenly distributed, so that the sheath 3 has good structural strength.
[0051] like Figure 4 As shown, the slider 21 includes an upper protrusion 44 and a lower protrusion 45, the inner ends of the upper protrusion 44 and the lower protrusion 45 are connected to the syringe holder 2, and the outer ends of the upper protrusion 44 and the lower protrusion 45 are connected to the transparent window 23. An air passage 46 is formed between the syringe holder 2, the upper protrusion 44, the lower protrusion 45 and the transparent window 23. The inner side surface of the transparent window 23 is a plane, and the outer side surface of the transparent window 23 is arc-shaped, which can achieve a convex magnification effect.
[0052] Specifically, the transparent window 23 is connected to the syringe holder 2 through an upper protrusion 44 and a lower protrusion 45, and is an integrated structure. The upper protrusion 44 and the lower protrusion 45 extend radially on the syringe holder 2 and are clamped in the movable groove 31, having a certain circumferential limiting effect. An air-separating channel 46 is formed between the upper protrusion 44 and the lower protrusion 45, and the internal situation can be observed through the transparent window 23 and the air-separating channel 46.
[0053] like Figure 5 , 6 As shown, a plurality of limiting ridge groups distributed along the circumferential direction are provided between the sheath 3 and the shell 1, the limiting ridge group includes a first limiting ridge 32 axially arranged on the outer wall of the sheath 3, a second limiting ridge 11 capable of cooperating with the first limiting ridge 32 is provided on the inner wall of the shell 1, and the first limiting ridge 32 and the second limiting ridge 11 of two adjacent limiting ridge groups along the circumferential direction are symmetrical along the axial direction of the shell 1, and the movable groove 31 is provided between two adjacent first limiting ridges 32. The first limiting ridge 32 is provided with a second step 33 arranged axially.
[0054] Specifically, the two first limiting convex strips 32 are located between the two second limiting convex strips 11, and the first limiting convex strips 32 and the second limiting convex strips 11 cooperate to form a limit in the rotation direction, and the movable groove 31 is arranged between the first limiting convex strips 32. The second step 33 is similar to the function of the reinforcing rib, which enhances the structural strength of the connection position between the first limiting convex strip 32 and the inner wall of the sheath 3.
[0055] like Figure 2 , 5 As shown in Figures 6 and 7, an anti-dropping step 34 is provided at the inner end of the sheath 3, and a first step 12 cooperating with the anti-dropping step 34 is provided on the second limiting convex strip 11. The anti-dropping step 34 is located at the upper end of the sheath 3, and the anti-dropping step 34 abuts against the first step 12, forming an axial limit between the sheath 3 and the housing 1.
[0056] like Figure 2 , 3As shown in FIG. 4 , the lower end of the slider 21 is provided with a buckle structure 4 that can be detachably fixed to the housing 1. The buckle structure 4 includes a hook 41 arranged at the lower end of the slider 21, and a buckle groove 42 and a buckle protrusion 43 that can cooperate with the hook 41 are provided on the inner wall of the housing 1. A stop protrusion 47 is provided at the lower end of the hook 41, and a stop groove 49 that cooperates with the stop protrusion 47 is provided on the lower step 48 at the lower end of the housing 1.
[0057] Specifically, the snap structure 4 is used for the detachable fixed connection between the syringe holder 2 and the shell 1. Specifically, the hook 41 hooks the snap-fit protrusion 43 to form an axial limiting connection, and a circumferential rotation limit is formed between the hook 41 and the side wall of the snap-fit groove 42. At the same time, the snap-fit groove 42 has a giving way effect on the hook 41. The stop protrusion 47 is used to snap with the snap-fit protrusion 43 to achieve axial limiting. The stop groove 49 is equivalent to a notch set on the lower step 48, which gives way to the stop protrusion 47 and also has a certain rotation limiting effect. The lower end of the second limiting protrusion 11 is connected to the lower step 48.
[0058] like Figure 2 , 4 As shown, a syringe holder 2 comprises a tubular sleeve 24, on which a syringe anti-dropping guide structure 25 is provided, at least one inner observation port 22 is circumferentially provided on the sleeve 24, a slider 21 connected to the sleeve 24 is provided on the outer side of the inner observation port 22, and a transparent window 23 with a convex magnifying effect is provided on the slider 21 for observing the liquid level through the inner observation port 22.
[0059] Specifically, a syringe is inserted and fixed in the barrel sleeve 24. The syringe anti-falling guide structure 25 is specifically a flared portion at the upper end. The syringe abuts against the flared portion to form a limit to prevent it from falling off from the inside. An internal observation port 22 is provided on the barrel sleeve 24. The liquid level of the medicine in the syringe can be observed through the transparent window 23 on the slider 21 through the internal observation port 22.
[0060] As an optimization, at least two axially arranged elastic support arms 26 are evenly arranged circumferentially at the lower part of the barrel sleeve 24. The lower end of the elastic support arm 26 is provided with a positioning protrusion protruding inward. The positioning protrusion has a certain radial elasticity and can be elastically clamped with the outer wall of the injection barrel to achieve the effect of stabilizing the barrel body of the injection barrel.
[0061] Preferably, the slider 21 is provided with a hook 41 that can cooperate with the housing 1. The hook 41 is used to achieve a detachable connection and fixation with the housing 1.
[0062] Specific working principle: After installation, the syringe filled with liquid medicine is located in the syringe holder 2 and is clamped and stabilized by the elastic support arm 26. The remaining amount of liquid medicine in the syringe can be observed through the external observation port 13 on the outer shell 1, the air-separating channel 46, the transparent window 23 on the slider 21, and the internal observation port 22 on the syringe holder 2 in sequence.
[0063] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.
Claims
1. A liquid level observation assembly for a syringe, comprising a tubular housing (1) and a syringe holder (2) arranged in the housing (1), a sheath (3) engaged with the housing being arranged between the housing (1) and the syringe holder (2), characterized in that: The sheath (3) is provided with at least one axially arranged movable groove (31) along the circumferential direction; the syringe holder (2) is provided with a slider (21) protruding from the holder (2) body and capable of at least partially engaging with the movable groove (31); an inner observation port (22) is provided on the syringe holder (2) on the inner side of the slider (21); an outer observation port (13) is provided on the outer shell (1) of the slider (21); and the slider (21) is provided with a transparent window (23) that enables the outer observation port (13) to observe the amount of medicine in the syringe through the inner observation port (22).
2. The liquid level observation assembly of the syringe according to claim 1, characterized in that: The sleeve (3) is provided with two axially arranged movable grooves (31) along the circumferential direction.
3. The liquid level observation assembly of the syringe according to claim 1, characterized in that: The slider (21) includes an upper protrusion (44) and a lower protrusion (45), the inner ends of the upper protrusion (44) and the lower protrusion (45) are connected to the syringe bracket (2), and the outer ends of the upper protrusion (44) and the lower protrusion (45) are connected to the transparent window (23), and an air-separating channel (46) is formed between the syringe bracket (2), the upper protrusion (44), the lower protrusion (45) and the transparent window (23).
4. The liquid level observation assembly of the syringe according to claim 1, characterized in that: The inner side surface of the transparent window (23) is a plane, and the outer side surface of the transparent window (23) is in an arc shape.
5. The liquid level observation assembly of the syringe according to claim 1, characterized in that: A plurality of limiting ridge groups distributed along the circumferential direction are provided between the sleeve (3) and the shell (1), the limiting ridge group comprising a first limiting ridge (32) axially arranged on the outer wall of the sleeve (3), a second limiting ridge (11) capable of cooperating with the first limiting ridge (32) being provided on the inner wall of the shell (1), and the first limiting ridge (32) and the second limiting ridge (11) of two adjacent limiting ridge groups along the circumferential direction are symmetrical along the axial direction of the shell (1), and the movable groove (31) is provided between two adjacent first limiting ridges (32).
6. The liquid level observation assembly of the syringe according to claim 5, characterized in that: The inner end of the sheath (3) is provided with an anti-slip step (34), and the second position-limiting convex strip (11) is provided with a first step (12) that matches the anti-slip step (34).
7. The liquid level observation assembly for a syringe according to any one of claims 1 to 6, characterized in that: The lower end of the slider (21) is provided with a snap-fit structure (4) that can be detachably fixed to the housing (1).
8. The liquid level observation assembly of the syringe according to claim 7, characterized in that: The buckle structure (4) comprises a hook (41) arranged at the lower end of the slider (21), and a buckle groove (42) and a buckle protrusion (43) capable of cooperating with the hook (41) are provided on the inner wall of the housing (1).
9. The liquid level observation assembly of the syringe according to claim 8, characterized in that: The lower end of the hook (41) is provided with a stop protrusion (47), and the lower step (48) at the lower end of the housing (1) is provided with a stop groove (49) that matches the stop protrusion (47).
10. The liquid level observation assembly for a syringe according to any one of claims 1 to 6, characterized in that: The main body of the syringe bracket (2) is provided with an elastic support arm (26) protruding toward the inside and used for axially supporting and stabilizing the syringe body. The elastic support arm (26) is circumferentially displaced relative to the slider (21).
11. A syringe holder, comprising a tubular sleeve (24), the sleeve (24) being provided with a syringe anti-dropping guide structure (25), the sleeve (24) being provided with at least one inner observation port (22) along the circumferential direction, characterized in that: A slider (21) connected to the barrel sleeve (24) is provided outside the inner observation port (22), and a transparent window (23) is provided on the slider (21) for observing the amount of medicine in the syringe through the inner observation port (22), and the inner side surface of the transparent window (23) is flat, and the outer side surface is arc-shaped.