WO2012126342A1

WO2012126342A1 - Structure for use in disposable injector and disposable injector

Info

Publication number: WO2012126342A1
Application number: PCT/CN2012/072527
Authority: WO
Inventors: 江波
Original assignee: 常州和康医疗器材有限公司
Priority date: 2011-03-18
Filing date: 2012-03-19
Publication date: 2012-09-27
Also published as: CN102688544A; CN202637628U; CN202844270U; WO2012126341A1; CN102688545A

Abstract

A structure for use in a disposable injector and the disposable injector using the structure. The structure comprises a deflection part (101 and 101a-d), a blocking part (103 and 103a-d), and a connecting part (102) connecting the deflection part (101 and 101a-d) to the blocking part (103 and 103a-d). The deflection part (101 and 101a-d) is capable of deflecting towards or away from the blocking part (103 and 103a-d). When the deflection part (101 and 101a-d) deflects towards the blocking part (103 and 103a-d), the deflection part (101 and 101a-d) leans on the blocking part (103 and 103a-d). The structure is not only applicable in pulling back a needle of the disposable injector, but also applicable in locking between a syringe and a core rod, and at the same time, allows for improved convenience and stability of injection operation.

Description

Structure and disposable syringe for disposable syringes

Technical field

The present invention relates to a structure for a disposable syringe and a disposable syringe to which the structure is applied.

Background technique

In order to avoid cross-infection when entering or removing media from humans or animals, the hypodermic syringe must be used once and disposed of as waste after use. The most widely used disposable syringes today consist of a hollow cylinder, a needle, and a fixed-range piston that fits within the barrel. The biggest problem with this kind of syringe is that after the injection is completed, the needle remains outside, which not only causes inconvenience to the handling and destruction of the syringe garbage, but also may injure the medical staff due to carelessness, resulting in the secondary cross of the bacteria. Infection, it becomes a medical hazard that cannot be ignored. In addition, there is still the possibility of being used twice, so there is a one-time use that can pull the needle back to the syringe after use. A syringe, such a disposable syringe, can be further configured to lock the retrieved needle within the barrel by a latching structure disposed on the core rod and the syringe to disable the disposable syringe. In addition to this, it is also possible to provide a break point on the core rod so that the core rod can be broken after the core rod is pulled back into position, ensuring that the disposable syringe can no longer be used.

In order to achieve the purpose of pulling the needle back to the syringe and locking the core rod in the barrel, it is generally required to provide one or more portions having a specific structure on the core rod. Passing one or more gates in one direction, the inner diameter of the gate is slightly smaller than the maximum outer diameter of the structure, and in the opposite direction, the gate cannot pass through unless the mechanical means exerts a sufficiently large external force on the structure, as in When the disposable syringe is assembled using a mechanical assembly machine.

For example, the application number is 201110066021.X In the Chinese invention application 'safety syringe and its self-destructing device', a tapered platform structure 11 as shown in Fig. 1 is arranged on the head of the core rod, and a shoulder is correspondingly provided on the side of the inner hole of the needle holder. Shape (gate) 12 The inner diameter of the shoulder portion 12 is slightly smaller than the diameter of the bottom surface of the conical table structure 11. When the head is pushed up, the conical table structure 11 can be pushed over the shoulder portion by the tapered surface thereof, and when it is pulled back, the conical table structure 11 The bottom surface is engaged with the shoulder 12 to apply a downward pulling force to the needle seat to pull the needle seat back into the barrel. The drawback of this structure is that during the injection, the process of pushing the tapered table structure 11 over the shoulder portion 12 needs to overcome a large resistance, which not only causes great inconvenience to the operator, but also makes the injection process not easy if the control is not good. Stable, even causing unnecessary pain to the person being injected.

The PCT patent application with the publication number WO2011/029264 discloses a 'needle tip retractable disposable safety syringe', as shown in Fig. 2. As shown, a pair of

engaging flanges

21, 22, respectively tapered and inverted, are disposed on the core rod at opposite intervals, and a matching shoulder having a right-angled edge is provided on the inside of the barrel. Shape 23 . When the core rod is pulled back, the engaging shoulder portion 23 is caught on the

engaging flange

21, 22 Between so that the core rod and the syringe are snapped together. A disadvantage of the above structure is that the inverted tapered engagement flange 22 is even assembled by the force of the mechanical assembly machine during assembly. It is also not possible to directly pass the shoulder, the hard push only damages the snap flange 22, and the funnel or tapered mounting ring must be used as shown in Figure 3. Auxiliary assembly, which adds a process and increases costs. In addition, the diameter of the front end of the syringe needs to be increased to make room for the assembly ring, and the increased diameter of the front end of the handle can also cause discomfort to the user who is accustomed to using a conventional syringe.

Accordingly, those skilled in the art are directed to the development of a specific structure that can be used for the pullback of a needle of a disposable syringe, and for the latching between the core rod and the syringe, and which can be overcome. The above drawbacks, as well as disposable syringes to which this structure is applied.

Summary of the invention

In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a structure for a disposable syringe and a disposable syringe to which the structure is applied, so that the pullback of the needle and the locking of the core rod are more It is lightweight and it is easier to assemble this disposable syringe.

In order to achieve the above object, the present invention provides in a first aspect A structure for a disposable syringe, the structure comprising a deflecting portion, a blocking portion, and a connecting portion connecting the deflecting portion and the blocking portion, the deflecting portion being deflectable toward or away from the blocking portion, when the deflecting portion is deflected toward the blocking portion, The deflecting portion abuts against the blocking portion.

In a preferred embodiment of the first aspect of the invention, the deflecting portion forms a bevel or a tapered surface when the deflecting portion abuts against the blocking portion

In another preferred embodiment of the first aspect of the invention, the deflecting portion is of a one-piece or split type.

In another preferred embodiment of the first aspect of the invention, the deflecting portion is circular, polygonal, petal or strip-shaped.

In another preferred embodiment of the first aspect of the invention, the structure is integrally injection molded.

In another preferred embodiment of the first aspect of the invention, the deflecting portion has a thin root, a thick edge.

In another preferred embodiment of the first aspect of the invention, the structure is disposed on a mandrel of a disposable syringe.

In another preferred embodiment of the first aspect of the invention, the structure is disposed inside the syringe of the disposable syringe.

In another preferred embodiment of the first aspect of the invention, the structure is disposed on the inner side of the central through hole of the hub of the disposable syringe.

The invention provides, in a second aspect, a disposable syringe comprising a syringe and a core rod, wherein the core rod comprises at least one structure provided by the first aspect of the invention, the inside of the barrel comprising at least one shoulder, the structure When set to pull back the core rod, the structure cannot pass down the shoulder.

In a preferred embodiment of the disposable syringe provided by the second aspect of the present invention, There are two structures on the core rod, the upper structure is the first structure, the lower structure is the second structure, and the first structure and the second structure are opposite; the inner side of the barrel is provided with the upper shoulder and the lower shoulder. The second structure is configured to pass down the upper shoulder when the core rod is pulled back after the injection is completed, but can no longer pass up the lower shoulder, and the first structure is set to not pass down the upper shoulder Shape.

further, In machine assembly of the disposable syringe, the second structure is configured to elastically deform the syringe to push upward over the upper shoulder and the lower shoulder.

In a preferred embodiment of the disposable syringe provided by the second aspect of the present invention, A platform and a structure are disposed on the core rod at intervals, and the table portion is above, the structure is lower, and the deflecting portion of the structure and the bottom surface of the table portion face each other; the inner side of the barrel is provided with an upper shoulder portion and a lower shoulder portion; an outer diameter of the table portion is larger than an inner diameter of the upper shoulder portion, and a circumference of the upper end surface of the table portion is provided as an inclined surface; the structure is disposed to pass downward through the upper shoulder portion, but can no longer Pass up through the lower shoulder.

Further, the structure is configured such that upon machine assembly of the disposable syringe, the structure can elastically deform the syringe and push up through the lower shoulder.

In a preferred embodiment of the disposable syringe provided by the second aspect of the present invention, the deflecting portion is of a one-piece or split type.

In a preferred embodiment of the disposable syringe provided in the second aspect of the invention, the deflecting portion is circular, polygonal, petal or strip-shaped.

In a preferred embodiment of the disposable syringe provided by the second aspect of the invention, the core rod is integrally injection molded.

In a preferred embodiment of the disposable syringe provided by the second aspect of the invention, the deflecting portion has a thin root portion and a thick edge.

The invention also provides, in a third aspect, a disposable syringe comprising a needle holder, a syringe and a core rod, wherein the core rod comprises at least one structure according to the first aspect of the invention, the needle holder is provided with a shoulder When the core rod is pulled back, the structure is set so that it cannot pass down the shoulder.

In a preferred embodiment of a disposable syringe provided by the third aspect of the present invention, Also included is a support member having a central through hole, the support member being coupled to the inner side of the syringe, the needle holder being held between the syringe and the support member; the core member including two structures, the upper structure being the first structure The lower structure is the second structure, and the first structure and the second structure are oriented in the same direction; the first structure is arranged to pass upward through the shoulder when injecting, but can not pass down through the shoulder when the injection is pulled back The second structure is configured to pass upward through the central through hole at the time of injection, but cannot pass down through the central through hole when the injection is completed.

In a preferred embodiment of a disposable syringe provided by the third aspect of the present invention, The deflection portion of the structure is a one-piece or sliced type.

In a preferred embodiment of a disposable syringe provided by the third aspect of the present invention, The deflecting portions of the structure are circular, polygonal, petal, and strip.

In a preferred embodiment of the disposable syringe of the third aspect of the invention, the core rod is integrally injection molded.

In a preferred embodiment of the disposable syringe of the third aspect of the invention, the deflecting portion has a thin root portion and a thick edge.

The structure provided by the invention can be applied to the pullback of the needle seat and to the latch between the core rod and the syringe, which can reduce the resistance of the pullback and latching process and make the injection process more Stable, the card lock process is more labor-saving, the assembly process is more simplified, and the production is convenient and the cost is low.

The concept, the specific structure and the technical effects of the present invention will be further described in conjunction with the accompanying drawings in order to fully understand the objects, features and effects of the invention.

DRAWINGS

Figure 1 shows a prior art structure for retracting a hub on a core rod.

Figure 2 shows the prior art latching structure between the syringe and the core.

Figure 3 shows an auxiliary assembly ring for assembly in the prior art.

4(a), 4(b), 4(c) and 4(d) show a specific embodiment of a structure and its different states in accordance with the present invention.

Figure 5 shows a specific embodiment of a deflection unit of the structure according to the invention.

Figure 6 shows another embodiment of a deflection section of a structure in accordance with the present invention.

Figure 7 shows another embodiment of a deflection section of a structure in accordance with the present invention.

Figure 8 illustrates a specific embodiment of a core rod of a disposable syringe employing the structure of the present invention.

Figure 9 illustrates a particular embodiment of a syringe that mates with the core rod of Figure 8.

Figure 10 is a schematic view showing the core rod of Figure 8 and the barrel of Figure 9 in a latched state.

Fig. 11 shows an enlarged view of A in Fig. 10.

Figure 12 shows an alternative embodiment at A in Figure 11.

Figure 13 illustrates a specific embodiment of a structure according to the invention applied to a hub of a disposable syringe.

Figure 14 illustrates an embodiment in which the structure according to the present invention is disposed inside the barrel.

Figure 15 shows another embodiment of a deflection portion of a structure in accordance with the present invention.

detailed description

Figure 4 shows a schematic view of an embodiment of a structure according to the invention, wherein the structure 100 comprises three parts in sequence: a deflection unit 101, a connection portion 102, a blocking portion 103, wherein the deflection portion 101 is arranged to be under external force, The deflecting portion 101 is deflected at the root portion 104 such that the deflecting portion 101 It can be deflected up and down, as shown in Figure 4(b) and Figure 4(c). The deflecting portion 101 is preferably made of a material having a certain flexibility such as plastic, so that when the external force is removed, the deflecting portion 101 can substantially return to the initial position as shown in Fig. 4 (a). The outer diameter of the deflecting portion 101 is larger than the outer diameter of the blocking portion 103. The outer diameter of the connecting portion 102 is smaller than the outer diameters of the deflecting portion 101 and the blocking portion 103, and the length of the connecting portion 102, that is, the spacing distance between the deflecting portion 101 and the blocking portion 103 is set to be when the deflecting portion 101 faces the blocking portion 102. The deflection may not continue to deflect due to the interference with the blocking portion 103, and the deflected deflecting portion 101 at this time forms a slope or a tapered surface 105. When 105 is a tapered surface (for example, when the deflecting portion 101 is circular), the deflecting portion 101 is generally shaped like a dish. The slope or taper of the bevel or tapered surface 105 can be adjusted by adjusting the length of the connecting portion 102, that is, the pitch of the deflecting portion 101 and the blocking portion 103, and/or the difference in outer diameter between the two. This adjustment is a conventional means for those skilled in the art. When the deflecting portion 101 is deflected in the opposite direction to the blocking portion 103, the deflecting portion 101 can be freely deflected because there is no restriction of the blocking portion 103.

The structure 100 is typically used in conjunction with a gateway, where the gateway refers to a through hole, a shoulder, an opening, and the like. The inner diameter of the gate that cooperates with the structure 100 is generally set to be larger than the outer diameter of the blocking portion 103 and smaller than the outer diameter of the deflecting portion 101, such that when the structure passes the gate forward with the blocking portion 103, the blocking portion 103 and the connecting portion 102 can pass through the gate without any hindrance, and the deflecting portion 101 can be freely deflected in the opposite direction to the blocking portion 103 under the action of the gate to easily pass the gate; and when the structure moves back, the deflecting portion 101 First, it is in contact with the gate, and the deflecting portion 101 is deflected toward the blocking portion 103 under the action of the gate and abuts against the blocking portion 103, so that the deflection cannot be continued. The bevel or cone 105 and the gate are arranged such that when the user performs a manual operation, the bevel or cone 105 is blocked at the gate and cannot pass. However, when a sufficiently large external force is applied to the structure 100 by means of a machine or the like, the bevel or tapered surface 105 can be pushed through the gate by elastically deforming the gate, thereby causing the structure 100 Pass the pass. The above technical effects can be achieved by manufacturing a bevel or a tapered surface as needed. The inclination or taper is achieved by selectively setting the ease of elastic deformation of the gate (related to the material, thickness, etc. of the gate), and such selection is conventional to those skilled in the art without any need Creative labor can be achieved.

The structure 100 is preferably integrally molded, and of course can also be assembled. The thickness of the deflecting portion 101 is preferably between 0.2 mm and 1.0 mm, and the length of the connecting portion 102, that is, between the deflecting portion 101 and the blocking portion 103. The separation distance is preferably less than 0.7 mm.

Further, the deflecting portion 101 may also be disposed to be unequal in thickness, as shown in FIG. 4(d), the root portion 104 of the deflecting portion 101 may be designed to be thinner to make it easier to deflect to form a bevel or tapered surface 105, while The edge portion of the deflecting portion 101 can be designed to be relatively thicker, such as 1.5 mm to 2.0 mm, such that the beveled or tapered surface 105 is less susceptible to deformation under the action of the gate and the barrier portion 103.

The deflection unit 101 has various possible embodiments, as shown in Figures 5, 6, and 7. The whole and multi-piece shown, as well as the circle or polygon, and the strip with a round head as shown in Figure 15. The deflection unit 101 is known to those skilled in the art. There are many equivalent embodiments such as a petal shape, a strip shape, a railing shape, an elliptical shape, etc., which may be provided with a single groove or a plurality of grooves, etc., and are all within the scope of the present invention.

8-11 illustrate one embodiment of applying the above described structure 100 to a latch between the disposable syringe plunger 1 and the syringe 2. As shown in Figures 8 and 11, two of the above-described structures 100 are spaced apart from the mandrel 1 of the disposable syringe, wherein the orientation of the first structure 100a above and the second structure 100b below is opposite. As shown in FIGS. 9 and 11, the inner side of the barrel 2 is provided with an upper shoulder portion 201 and a lower shoulder portion 202, and wherein the outer diameters of the first blocking portion 103a and the second blocking portion 103b are less than or equal to the upper shoulder. The outer diameter of the first deflecting portion 101a is larger than the inner diameter of the upper shoulder portion 201, and the outer diameter of the second deflecting portion 101b is larger than the inner diameter of the lower shoulder portion 202. The interval between the first deflecting portion 101a and the second deflecting portion 101b is greater than or equal to the interval between the upper shoulder portion 201 and the lower shoulder portion 202 . For ease of manufacture, the dimensions of the portions of the first structure 100a and the second structure 100b are preferably identical; the inner diameters of the upper shoulder 201 and the lower shoulder 202 are preferably identical. and The second structure 100b is configured to pass downwardly through the upper shoulder 201 when the core rod is pulled back after the injection is completed, but can no longer pass upward through the lower shoulder 202, and the first structure 100a It is then set so as not to pass downward through the upper shoulder 201.

The core rod and the syringe using the above arrangement can be assembled by mechanical assembly methods commonly used in the prior art, such as assembly on a conventional syringe disc type automatic mechanical assembly machine, without the use of an auxiliary assembly ring. This is because the first blocking portion 103a of the first structure 100a can pass through the upper shoulder portion 201 and the lower shoulder portion 202 without any hindrance during assembly, and the first deflecting portion 101a of the first structure 100a faces away from the first The direction of the blocking portion 103a is free to deflect and can easily pass through the upper shoulder portion 201 and the lower shoulder portion 202, while the second deflecting portion 101b of the second structure 100b is subjected to the second blocking portion due to its deflection toward the second blocking portion 103b. The bevel or the tapered surface is formed by the limitation of the circumference of the 103b. However, unlike the reverse taper of the engaging flange 202 in Fig. 2, the inclined surface or the tapered surface formed by the second deflecting portion 101b is formed by the mechanical force and the inertial force. The barrel is configured to be elastically deformable by the force applied by the assembly machine, and is squeezed through the upper shoulder portion 201 and the lower shoulder portion 202 during assembly to fit into the barrel 2. When the core rod 1 is pulled back, both the inclined surface or the tapered surface of the first structure 100a and the second structure 100b are set so that the force generated by the operator's manual operation is not pushed over the upper shoulder 201 or the lower shoulder 202. Thereby, the locking between the core rod 1 and the syringe 2 is achieved.

By adopting such a locking method, on the one hand, the assembly ring can be eliminated during assembly, thereby saving the process and cost, and the assembly method is the same as that of the ordinary disposable syringe, and can be assembled on the existing automatic assembly machine. On the other hand, when the back-pull core rod 1 is used for locking, no hard pressing process is required, so the resistance of the entire pull-back and latching process is small, and it is easy and labor-saving.

In addition, the first structure 100a may be replaced with a table portion 105 having an outer diameter larger than that of the upper shoulder portion 201 as shown in FIG. 12, wherein the circumference of the upper end surface of the table portion 105 is formed as an inclined surface for assembly. Since the table portion 105 needs to be squeezed through the upper shoulder portion 201 having an inner diameter smaller than that during assembly, this configuration makes the resistance to be overcome during assembly greater.

In addition, only the first structure 100a can be disposed on the core rod 1, and only the upper shoulder portion 201 is disposed on the barrel 2. At this time, the first structure 100a can prevent the core rod 1 from being pulled out of the syringe when pulled back. 2, that is, like the function of the stop structure on the ordinary syringe, and the advantage of this arrangement is also that the assembly is more convenient and labor-saving than the stop structure on the ordinary syringe.

Figure 13 shows an embodiment of the application of the structure according to the invention to the pullback of a needle holder, in which 3 is a needle hub, 2 is a syringe, 4 is a support with a central through

hole

41, and 5 is a core The head of the rod 1 is connected to a slot 25 in the barrel 2, the needle holder 3 is positioned between the barrel 2 and the support member 4, and the inner hole 31 of the needle holder 3 is also provided with a shoulder shape. Part 32. As shown in the figure, the third structure 100c and the fourth structure 100d are disposed at intervals on the head 5 of the core rod 1, wherein the third structure 100c and the fourth structure 100d are oriented in the same direction, and the third blocking portion 103c is The outer diameter is smaller than the inner diameter of the central through hole 41 of the shoulder portion 32 and the support member 4, the outer diameter of the fourth blocking portion 103d is smaller than the inner diameter of the central through hole 41 of the support member 4, and the outer diameter of the third deflecting portion 101c is larger than the shoulder shape. The inner diameter of the portion 32 and the outer diameter of the fourth deflecting portion 101d are larger than the inner diameter of the center through hole 41 of the support member 4. In addition, the outer diameter of the third deflecting portion 101c may also be set smaller than the inner diameter of the center through hole 41, so that the third structure 100c can pass through the center through hole 41 without any trouble. At the time of injection, the third deflecting portion 101c of the third structure 100c easily passes through the shoulder portion 32 provided in the inner hole 31 of the hub 3 by being freely deflected in a direction away from the third blocking portion 103c, the fourth structure 100d The fourth deflecting portion 101d easily passes through the center through hole 41 of the support member 4 by being freely deflected in a direction away from the fourth blocking portion 103d. When the core rod 1 is pulled back after the injection is completed, the fourth sheet member 101d of the fourth structure 100d is deflected toward the fourth blocking portion 103d, and the fourth sheet member 101d can only be slightly deflected due to the restriction of the fourth blocking portion 103d. Immediately against the circumference of the fourth blocking portion 103d, a downward pulling force is applied to the support member 4 to disengage the support member 4 from the syringe 2. Similarly, during the pulling back of the third structure 100c, the third deflecting portion 101c abutting against the third blocking portion 103c pulls the hub 3 back into the barrel 2 through the shoulder portion 32.

In the above embodiment, since the structure according to the present invention is employed, the process resistance of the head 5 of the core rod 1 through the center through hole 41 and the shoulder portion 32 of the support member 4 is small, so that the operator operates very well. Freely, the whole process is more stable, reducing the discomfort of the person being injected.

It will be understood by those skilled in the art that the structure 100 according to the present invention can in turn be disposed on the inner wall of the barrel 2, and a shoulder portion can be provided on the core rod 1 to achieve The lock between the core rod 1 and the syringe 2; the structure 100 according to the invention can also be reversely arranged on the central through hole 31 of the needle holder 3, and the shoulder of the core rod 1 can be fitted a portion for retracting the core rod 1 to the needle holder 3. Figure 15 shows an embodiment in which the structure 100 is placed on the inside of the barrel 2.

The upper or lower direction as referred to in the present application refers to the direction of the needle or the mandrel handle of the disposable syringe, respectively; the outer diameter of the deflecting portion or the blocking portion refers to the maximum length in the lateral direction when deflected When the portion or the blocking portion is circular, the outer diameter is its diameter. The inner diameter of the central through hole or shoulder is the maximum length of the space defined by the central through hole or the shoulder in the lateral direction, and the inner diameter when the space defined by the central through hole or the shoulder is circular It is its diameter.

The above has described in detail the preferred embodiments of the invention. It will be appreciated that many modifications and variations can be made in the present invention without departing from the scope of the invention. Therefore, any technical solution that can be obtained by a person skilled in the art based on the prior art based on the prior art by logic analysis, reasoning or limited experimentation should be within the scope of protection determined by the claims.

Claims

A structure for a disposable syringe, the structure comprising a deflecting portion, a blocking portion, and a connecting portion connecting the deflecting portion and the blocking portion, the deflecting portion being deflectable toward or away from the blocking portion, The deflecting portion abuts against the blocking portion when the deflecting portion is deflected toward the blocking portion.
A structure for a disposable syringe according to claim 1, wherein said deflecting portion forms a slope or a tapered surface when said deflecting portion abuts against said blocking portion.
A structure for a disposable syringe according to claim 1, wherein said deflecting portion is of a one-piece type or a slice type.
A structure for a disposable syringe according to claim 1, wherein said deflecting portion is circular, polygonal, petal-shaped or strip-shaped.
A structure for a disposable syringe according to claim 1, wherein said deflecting portion has a thin root portion and a thick edge.
A structure for a disposable syringe according to claim 1 wherein said structure is integrally injection molded.
A structure for a disposable syringe according to claim 1 wherein said structure is disposed on a stem of said disposable syringe.
A structure for a disposable syringe according to claim 1 wherein said structure is disposed inside a barrel of said disposable syringe.
A structure for a disposable syringe according to claim 1, wherein said disposable syringe further comprises a needle hub, said structure being disposed inside a central through hole of said hub.
A disposable syringe comprising a syringe and a core rod, wherein the core rod includes at least one structure as claimed in claim 1, the inside of the barrel including at least one shoulder, the structure being configured to be back When the mandrel is pulled, the structure cannot pass down through the shoulder.
The disposable syringe of claim 10, wherein

Included in the core rod are two of the structures, the structure above is a first structure, the lower structure is a second structure, and the first structure and the second structure are opposite;

The inner side of the barrel is provided with an upper shoulder portion and a lower shoulder portion;

The second structure is configured to pass downwardly through the upper shoulder when the mandrel is pulled back after the injection is completed, but can no longer pass upward through the lower shoulder, and the first structure is Set to not pass down through the upper shoulder.
A disposable syringe according to claim 11 wherein said second structure is configured to push upwardly through said upper shoulder by elastically deforming said syringe when machine assembling said disposable syringe And lower shoulders.
The disposable syringe of claim 10, wherein

A mesa portion and the structure are disposed at intervals on the core rod, and the table portion is above, the structure is lower, and the deflecting portion of the structure and the bottom surface of the table portion are Face each other;

The inner side of the barrel is provided with an upper shoulder portion and a lower shoulder portion;

The outer diameter of the table portion is larger than the inner diameter of the upper shoulder portion, and the circumference of the upper end surface of the table portion is provided as an inclined surface;

The structure is configured to pass downwardly through the upper shoulder but not upwardly through the lower shoulder.
A disposable syringe according to claim 13 wherein said structure is configured to resiliently deform said syringe to force upwardly through said lower shoulder when machine assembling said disposable syringe unit.
A disposable syringe according to claim 10, wherein said deflecting portion is of a one-piece or split type.
A disposable syringe according to claim 10, wherein said deflecting portion is circular, polygonal, petal or strip-shaped.
The disposable syringe of claim 10 wherein said core rod is integrally injection molded.
A disposable syringe according to claim 10, wherein said deflecting portion has a thin root portion and a thick edge.
A disposable syringe comprising a needle holder, a syringe and a core rod, wherein the core rod includes at least one structure according to claim 1, the needle holder is provided with a shoulder portion, when the pull back is In the case of a mandrel, the structure is arranged to not pass downwardly through the shoulder.
The disposable syringe of claim 19, wherein

Also included is a support having a central through hole, the support being attached to an inner side of the barrel, the needle holder being held between the barrel and the support;

The core rod includes two structures, the upper structure is a first structure, the lower structure is a second structure, and the first structure and the second structure are oriented in the same direction;

The first structure is configured to pass upwardly through the shoulder when injecting, but can no longer pass down the shoulder when the injection is completed;

The second structure is configured to pass upwardly through the central through hole at the time of injection, but may not pass down through the central through hole when the injection is completed.
A disposable syringe according to claim 19, wherein said deflecting portion is of a one-piece or split type.
A disposable syringe according to claim 19, wherein said deflecting portion is circular, petal or strip shaped.
A disposable syringe according to claim 19, wherein said core rod is integrally injection molded.
A disposable syringe according to claim 19, wherein said deflecting portion has a thin root portion and a thick edge.