WO2006076829A1

WO2006076829A1 - A disposable syringe

Info

Publication number: WO2006076829A1
Application number: PCT/CN2005/000092
Authority: WO
Inventors: Hsienwen Hsieh
Original assignee: Hsienwen Hsieh
Priority date: 2005-01-21
Filing date: 2005-01-21
Publication date: 2006-07-27

Abstract

A disposable syringe includes a needle barrel (l), a pushing rod (2), a needle hub (l 1) and a needle component (4). The needle component (4) includes a needle tube hub (41), a needle tube sheath (42), and a needle tub (43). A hermetic locking ring (44) is fitted on the outer end face of the cylindrical step (422) at the rear end of the needle tube sheath (42). There is a clamping hook (21) facing the hermetic locking ring (44) at the front end of the pushing rod (2). When the clamping hook (21) completely pushes the hermetic locking ring (44) off the outer end face of the cylindrical step (422) at the rear end of the needle tube sheath (42), the clamping hook (21) is able to be clamped on the end face (432) of the cylindrical step (422), causing the needle tube sheath (42) together with the needle tube (43) to retract into the needle barrel (l) due to the withdraw of the pushing rod (2), thus preventing the reuse of the syringe.

Description

Single-use safety syringe

This invention relates to syringes in the field of medical devices, and more particularly to a disposable safety syringe. Background technique .

As is well known, a syringe is a commonly used medical device. In order to prevent cross-infection, the one-time use of syringes has received increasing attention. However, the existing syringes generally do not have a self-destructive protective structure, so that the existing syringes are not strictly "one-off" in terms of performance, and can be repeatedly used, leaving hidden dangers for cross-infection, easy Cause the spread of disease. In addition, during the processing of the existing syringe after the injection, the exposed needle is extremely easy to stab or scratch the surrounding person, resulting in a new cross infection.

The safety syringe of Chinese Patent No. 98250220.6 consists of a syringe, a needle assembly, a snap seat, a push rod and a chuck. Wherein the engaging seat is located at the front end of the syringe, and the needle assembly is combined with the front end of the engaging seat. The rear end of the engaging seat has a hole. The chuck is placed at the front end of the push rod. When the push rod is advanced toward the front end of the injection cylinder, the chuck engages with the engaging seat. When the push rod is pulled back, the engaging seat is pulled together with the needle assembly into the housing of the syringe to prevent the needle from stabbing the human body for the purpose of single use. However, due to the unreasonable design structure of the syringe, there are technical defects such as large residual amount of liquid medicine and poor sealing after the injection, the product performance is not stable enough, and it is not in line with the state regarding the residual amount of the injected liquid. Provisions.

Also disclosed in the patent application of WO 02/087669 is a safety syringe comprising a needle cannula, a needle cannula, a needle hub, a sealing element, a spring. It has the function of automatically destroying the syringe after the injection is completed. However, the structure of the syringe is too complicated, increasing production costs. In addition, this structure also causes defects in which a large amount of liquid remains. Moreover, when the safety syringe is in use, when the injection action is completed, the needle automatically pops out of the patient's body and enters the syringe before the medical staff has unplugged the needle from the patient, thereby causing great pain to the patient. . Therefore, the practicality is poor. Summary of the invention

SUMMARY OF THE INVENTION The object of the present invention is to provide a disposable safety syringe having a protective self-destructing structure and a thorough injection of the drug solution, in view of the drawbacks of the prior art syringe.

The single-use safety syringe of the present invention comprises: a syringe; a push rod disposed in the barrel having a portion that conforms to an inner wall of the barrel and slidable along an inner wall of the barrel; a needle holder is integrally formed at a front end of the syringe;

a needle portion is mounted on the needle seat, the needle portion comprising: a needle tube seat, a needle tube sleeve, Needle;

The rear end of the needle sleeve has a cylindrical step, and the center thereof is a through hole; the needle tube is installed in the through hole of the needle tube sleeve, and the needle tip protrudes from the needle tube sleeve; the center of the needle tube holder is continuous a cavity, the needle tube seat and the needle seat have a mating connection structure, wherein: a sealing lock ring is mounted on an outer end surface of the cylindrical step at the rear end portion of the needle tube sleeve, and the sealing lock ring is fitted a distal end portion of the cavity of the needle hub; the front end of the push rod has at least one hook, the hook is opposite to the sealing lock ring, and the shape of the hook and the end of the step toward the end of the needle tip Face to match.

After the hook pushes the sealing lock ring completely away from the outer end surface of the cylindrical step of the rear end portion of the needle sleeve, the hook buckle can be on the end surface of the step, so that the needle sleeve and the needle tube can follow The push rod is pulled back and retracted into the syringe to avoid reuse.

Since the safety syringe is completely in contact with the bottom of the syringe at the time of injection, the residual liquid is avoided. In addition, due to the special needle structure, it is beneficial to protect the entire syringe from self-destruction and truly achieve the purpose of single use. DRAWINGS

1 is a schematic view showing the appearance of a syringe according to an embodiment of the present invention;

2 is a cross-sectional view showing the internal structure of a syringe according to an embodiment of the present invention;

3 is a cross-sectional view showing a needle hub of an embodiment of the present invention;

4 is a cross-sectional view showing a needle sleeve of an embodiment of the present invention;

Figure 5 is a cross-sectional view showing a syringe of an embodiment of the present invention;

Figure 6 is a partial enlarged view of a portion A in Figure 2;

Figure 7 is a schematic view of the B direction in Figure 6;

Figure 8 is a cross-sectional view showing a push rod holder according to an embodiment of the present invention;

Figure 9 is a cross-sectional view showing a portion of a push rod with a thrust boss according to an embodiment of the present invention;

FIG. 10 is a schematic structural view of a hook according to a second embodiment of the present invention; FIG.

Figure 11 is a schematic view of the C direction in Figure 10;

Figure 12 is a cross-sectional view showing the structure of a hook according to a third embodiment of the present invention. detailed description

As shown in Figures 1 and 2, the disposable safety syringe of the present invention comprises a syringe 1, a push rod 2, a push rod piston 3, and a needle portion 4. The push rod piston 3 is attached to the front end portion of the push rod 2. The largest portion of the outer diameter of the push rod piston 3 coincides with the inner wall of the barrel 1 and is slidable longitudinally along the inner wall. A needle holder 11 is provided at the front end of the syringe 1, and the needle holder 11 can be integrally molded with the syringe 1 during processing. The needle portion 4 is mounted on the needle hub 11. This part of the technology is similar to existing syringes and will not be described in detail here. As shown in FIG. 2, the needle portion 4 includes a needle hub 41, a needle cannula 42, a needle tube 43, and a seal lock ring 44.

As shown in Fig. 2 and Fig. 3, the center of the needle hub 41 is a through cavity 411 which can accommodate the needle can 42 and allow the needle can 42 to slide in the longitudinal direction. A hollow cylinder 415 is integrally formed on the end surface of the rear end portion of the needle hub 41 and the needle hub 41. The cylinder 415 is concentric with the needle hub 41, and the inner diameter thereof is tightly matched with the outer diameter of the sealing lock ring 44, and the height thereof is larger than the seal lock. The height of the ring 44 is twice. The outer cylindrical surface 416 of the circular cylinder 415 is a conical surface. An external thread 413 is provided on the outer circumferential surface of the joint between the cylinder 415 and the needle hub 41. Under the push of the push rod 2, in order to prevent the needle sleeve 42 from sliding forward, the front end of the cavity of the needle hub 41 has a centrally-retracted catch 46.

As shown in Fig. 2 and Fig. 4, the needle sleeve 42 has a hollow shape, and a central portion thereof is formed with a longitudinal through hole 421. A radially protruding cylindrical step 422 is formed at the rear end of the needle sleeve 42: a circular groove 430 is formed inwardly from the outer edge on the end surface 432 of the cylindrical step 422 toward the needle tip 431-end, in this embodiment The cross-sectional shape of the groove 430 is a triangle, and may of course be 'other geometric shapes'. The needle tube 43 is mounted in the through hole 421 of the needle cannula 42 such that the bottom surface thereof is flush with the bottom surface 427 of the needle cannula 42 to further reduce the residual of the chemical liquid at the time of injection. The needle tip 431 protrudes beyond the needle cannula 42 for easy injection. The needle tube 43 is bonded to the needle cannula 42 so that the needle tube 43 does not retract into the needle cannula 42 at the time of injection. The diameter of the front end of the through hole 421 is varied, and is composed of the following five through holes: First, a cylindrical through hole 424 is formed inwardly from the front end surface 423, and the cylindrical through hole 424 extends inward to form a conical through hole 425. The conical through hole 425 extends inwardly with a spherical through hole 426. The spherical through hole 426 further extends inwardly with a cylindrical through hole 429. Finally, the cylindrical through hole 429 extends inward to form a cylindrical through hole 428. The diameter of the through hole 428 is the smallest of all the through holes, and is the same as the outer diameter of the needle tube 43, and the two are tight fits. The center diameter of the spherical through hole 426 is the same as the diameter of the cylindrical through hole 424, and the diameter of both ends is the same as the diameter of the small end of the cylindrical through hole 429 and the conical through hole 425, respectively, and the diameters of the above five through holes are It is smaller than the diameter of other portions of the through hole 421. The change diameter is designed such that when the needle tube 43 and the needle sleeve 42 are glued, the glue can smoothly enter the inner wall surfaces of the through holes 424, 425, 426, and 429, and the accumulation is formed in the spherical through holes 426. The needle tube 43 can be more firmly bonded in the through hole 421.

As shown in FIG. 2, the seal lock ring 44 has a circular ring shape, is mounted on the outer end surface of the cylindrical step 422 at the rear end portion of the needle tube sleeve 42, and is caught at the rear end portion of the cavity 411 of the needle tube seat 41. That is, the seal lock ring 44 is fastened between the outer end surface of the cylindrical step 422 at the rear end portion of the needle tube sleeve 42 and the end portion of the cavity 411 of the needle hub 41. The sealing lock ring 44 on the one hand ensures a seal between the needle cannula 42 and the needle cannula 41, and on the other hand the needle cannula 42 (along with the needle cannula 43) is fixedly mounted on the needle cannula 41. In a preferred embodiment of the present invention, in order to reduce the friction between the seal lock ring 44 and the needle hub 42 and the needle hub 41, the outer circumferential surface thereof is a conical surface having a diameter from the opposite side of the hook 21. One end begins to shrink gradually. The needle hub 41 has a mating connection structure with the needle hub 11 at the front end of the syringe 1. As shown in Fig. 5, the syringe 1 is a hollow cylinder integrally formed at a joint portion of the front portion thereof with the needle hub 41 to form a needle holder 11. The needle holder 11 is a hollow cylinder concentric with the barrel 1, and is provided with an internal thread on the inner wall surface in the front end thereof; and the inner wall surface 112 at the rear end thereof is a conical surface. A conical surface 12 is formed on the inner wall surface of the rear end of the barrel 1.

As shown in FIG. 3 and FIG. 5, the mating connection structure between the needle hub 41 and the needle hub 11 at the front end of the syringe 1 can be a spiral connection structure: In this embodiment, the needle holder 11 is an inner spiral, and the needle holder 41 is External spiral. Of course, it is also possible that the needle hub 11 is an outer spiral and the needle hub 41 is an inner spiral. The conical surface of the inner wall surface 112 of the rear end of the needle hub 11 cooperates with the conical surface of the outer cylindrical surface 416 of the cylindrical body 415 of the needle hub 41. Thereby, a tight fit can be produced when the needle hub 41 is coupled to the needle hub 11, and after the needle hub 41 and the needle hub 11 are screwed to each other, the distal end portion of the cavity 411 of the needle hub 41 can be produced to the seal lock ring 44. The radial pressure causes the seal lock ring 44 to be more closely fitted between the rear end step 422 of the needle cannula 42 and the distal end portion of the cavity 411 of the needle cannula 41.

In another embodiment of the invention, the mating connection structure is an embedded card structure. The front end 111 of the needle hub 11 is an embedded bayonet, and the rear end 413 of the needle hub 41 is a latch that cooperates with the bayonet.

The above structure of the present invention, when assembled, assembles the needle hub 41 with the needle hub 11 through its mating structure. .

As shown in Figs. 2, 6, and 7, the front end of the push rod 2 has at least one hook 21 made of an elastic material such as medical plastic. In the present embodiment, there are two hooks 21 which are evenly spaced and oppositely disposed on the same circumference. The two hooks 21 respectively include a body 211 and a hook portion 212 formed integrally with the body 211. The two bodies 211 are opposite the seal lock ring 44 and have a length greater than the height of the rear end step 422 of the needle tube sleeve 42. The length of the body 211 ensures that the hook 21 can be snapped into the recess 430 after the hook 21 completely pushes the seal lock ring 44 away from the outer end surface of the cylindrical step 422 at the rear end portion of the needle sleeve. The body 211 is an elongated plate-like body having a cross-sectional shape of a cylindrical wall which is uniformly distributed on the annular cylinder, the arc of which is the same as the circular arc of the sealing lock ring 44, and the section thickness is slightly smaller than the wall of the sealing lock ring 44. thick. The body 211 integrally extends inwardly to form a hook portion 212, and an angle between the inner surface 213 of the hook portion 212 and the inner surface 214 of the body 211 is less than 90 degrees. The shape and size of the two hook portions 212 cooperate with the groove 430 of the needle sleeve 42. In the present embodiment, the hook portion 212 has a triangular cross section to ensure that the hook portion 212 when the hook 21 pushes the sealing lock ring 44 apart. It can be hooked in the recess 430. The hook 21 is used to advance the seal lock ring 44 in the needle hub 41 when the injection is completed. When the seal lock ring 44 is pushed away from the rear end step 422 of the needle cannula 42 by the hook 21, the constraint on the needle cannula 42 can be released. When the hook 21 pushes the lock ring 44, the thickness of the cross section of the body 211 of the hook 21 is slightly smaller than the wall thickness of the seal lock ring 44, that is, the cylindrical step 422 smaller than the rear end of the needle sleeve 42 and the rear end of the needle hub 41. Gap distance between hollow cylinders 415, and hook hooks The maximum thickness of the section 212 is less than or equal to the wall thickness of the sealing lock ring 44, and since the hook 21 is made of an elastic material, the hook 21 generates an outward elastic deformation when the sealing lock ring 44 is pushed, thereby ensuring When the hook 21 pushes the seal lock ring 44, the hook 21 can move in the gap between the cylindrical step 422 at the rear end of the needle hub 42 and the hollow cylinder 415 at the rear end of the needle hub 41; when the hook 21 will When the sealing lock ring 44 is completely pushed away from the step 422, the hook portion 212 is hooked inwardly against the recess 430 of the needle cannula 42 by the elastic restoring force.

10 and 11 are schematic views showing the structure of a hook 21 according to a second embodiment of the present invention. As shown in Figs. 10 and 11, in the present embodiment, the front end of the push rod 2 has three hooks 21 made of an elastic material such as medical plastic. The three hooks 21 are disposed at equal intervals of 120 degrees on the same circumference. It can ensure that when the push rod 2 is pulled back, the hook 21 can be firmly hooked in the groove 430 of the needle sleeve 42, and the needle sleeve 42 (along with the needle tube 43) can be smoothly pulled back into the barrel 1.

Figure 12 is a cross-sectional view showing the structure of a hook 21 according to a third embodiment of the present invention. As shown in Fig. 12, the hook portion 212 of the hook 21 has a right-angled triangle. That is, the angle between the inner surface 213 of the hook portion 212 and the inner surface 214 of the body 211 is equal to 90 degrees. Therefore, in the present embodiment, the recess 430 is not required to be formed on the step 422 of the needle sleeve 42, but is directly hooked on the end surface 432 of the step 422 toward the end 432 of the needle tip 432 by the inner surface 213 of the hook portion 212. The needle cannula 42 (along with the needle cannula 43) is thereby pulled back into the syringe 1 with the pusher 2. Of course, the cross-section of the hook portion 212 can also be trapezoidal or other geometric shape, as long as the inner surface 213 of the hook portion 212 can be hooked on the end surface 432 of the step 422 toward the tip end of the needle tip 431 and the cannula sleeve 42 (along with the needle tube 43) Pull back into the syringe 1.

As shown in FIG. 2, FIG. 5, FIG. 8, and FIG. 9, in order to prevent the hook 21 of the push rod 2 from being accidentally forced to push the seal lock ring 44 to slide forward, a stopper function is provided at the rear end of the syringe 1. Push rod support 6. The push rod holder 6 is a cylindrical body having a through hole 61 in the middle. The diameter of the through hole 61 is slightly larger than the diameter of the push rod 2, so that the push rod 2 can be inserted into the through hole 61 and can slide in the through hole. The outer wall surface 63 of the hollow cylinder provided inside the cylinder 1 is a conical surface, and the inner wall surface 12 of the cylinder 1 in contact with the conical surface 63 of the push rod holder 6 is also opposite to the outer wall surface 63. The conical surface is fitted, and the small end diameter of the inner wall surface 12 is smaller than the large end diameter of the outer wall surface 63. Thereby, the push rod holder 6 can be clamped to the rear end of the barrel 1 without being pushed into the barrel 1. At least one thrust groove 62 is formed on the inner wall surface of the hollow cylindrical portion of the push rod holder 6 disposed outside the barrel 1. The circumferential surface at the corresponding position of the rear end of the push rod 2 is provided with the thrust groove 62. Fitted thrust boss 22. When the syringe is not in use or when the medical staff pulls the push rod 2 forward in order to suck the liquid medicine, the thrust boss 22 of the push rod 2 is pushed against the thrust groove 62 of the push rod support 6 and pushed forward. After the lever 2, the thrust boss 22 will be blocked by the thrust groove and cannot continue to advance, thereby ensuring that the seal lock ring 44 is not accidentally opened by the hook 21. When the injection is performed, it is only necessary to shift the thrust boss 22 and the thrust groove 62 to push the pusher 2, that is, to make the thrust boss 22 face the hollow cylindrical portion of the pusher holder 6. The other part of the non-stop groove 62 on the inner wall surface is pushed to perform the injection.

After the injection is completed, the hook 21 pushes the sealing lock ring 44 away from the rear end step 422 of the needle cannula 42. When the hook 21 completely pushes the sealing lock ring 44 away from the rear end step 422 of the needle cannula 42, the hook The bottom surface 23 of the 21 is in contact with the end end surface 427 of the needle hub 42, ensuring that the residual amount of the chemical liquid is small. When the needle tip 431 is pulled out from the patient body, and then the push rod 2 is pulled back, since the hook portion 212 of the hook 21 is hooked inwardly in the groove 430 of the needle tube sleeve 42 under the elastic restoring force, Therefore, the needle cannula 42 (along with the needle cannula 43) will be retracted into the syringe 1 following the pullback action of the pusher 2.

As shown in FIG. 2, after the injection work of the syringe of the present invention, the push rod piston 3 is completely in contact with the bottom of the syringe 1, since the shape of the push rod piston 3 coincides with the shape of the inner wall of the syringe 1, and the hook is A notch 211 is formed in the opening 21, so that the liquid medicine outside the hook 21 can enter the inside of the hook 21 from the notch 211 and be injected into the needle tube 43, thereby avoiding the residue of the chemical liquid.

When the disposable pusher 2 is pushed again after the single use, since the needle cannula 42 is rebounded into the syringe 1, the needle cannula 42 cannot be positioned to prevent reuse. It is also possible that since the needle hub 42 and/or the needle tube 43 push the push rod 2 forward again, it will be placed on the catch 46 and cannot be protruded from the top opening of the needle hub 41 to be crushed. At the same time, the push rod 2 can be broken so that the entire syringe can no longer be used, so that the syringe can be self-destructed for one use only, avoiding repeated use of the syringe.

In summary, the present invention is a controllable self-destructive behavior. Since the retraction of the needle cannula 43 of the present invention is performed after the needle tip 431 is pulled out of the patient, it does not cause pain to the patient, and the syringe disclosed in WO 02/087669 is well overcome when the needle is rebounded. It brings painful defects to the patient; and it also overcomes the problem of a large amount of residual liquid in the prior art due to unreasonable structure.

Claims

Rights request:

1. Single-use safety syringes, including:

Syringe (1);

a push rod (2) disposed in the barrel (1) having a portion that fits with an inner wall of the barrel (1) and sliding along the inner wall of the barrel;

A needle holder (11) is integrally formed at a front end of the syringe (1); and

A needle portion (4) is mounted on the needle hub (11), the needle portion (4) comprising a needle hub (41), a needle can sleeve (42), and a needle tube (43);

The rear end of the needle sleeve (42) has a cylindrical step (422), the center of which is a through hole (421); the needle tube (43) is installed in the through hole (421) of the needle sleeve (42), And the needle tip (431) protrudes from the needle sleeve (42); the center of the needle holder (41) is a through cavity (411), and the needle sleeve (42) is installed in the cavity (411). There is a mating connection between the needle hub (41) and the needle holder (11), characterized in that a sealing ring is mounted on the outer end surface of the cylindrical step (422) at the rear end of the needle sleeve (42). (44), the seal lock ring (44) is snapped at a distal end portion of the cavity (411) of the needle hub (41); the front end of the push rod (2) has at least one hook (21), The hook (21) is opposite to the sealing lock ring (44), and the shape of the hook (21) is matched with the end surface (432) of the step (422) toward the needle tip (431) end;

When the hook (21) completely pushes the sealing lock ring (44) away from the outer end surface of the cylindrical step (422) at the rear end portion of the needle tube sleeve (42), the hook (21) can be buckled On the end surface (432) of the step (422), the needle sleeve (42) together with the needle tube (43) can be retracted into the syringe (1) with the pullback of the push rod (2), avoiding reuse .

2. The syringe according to claim 1, wherein the front end of the push rod (2) has two hooks (21) which are evenly spaced and disposed opposite each other on the same circumference.

3. A syringe according to claim 1, characterized in that the front end of the push rod (2) has three hooks (21) arranged on the same circumference at equal intervals of 120 degrees.

The syringe according to claim 1 or 2 or 3, characterized in that the hook (21) comprises a body (211) and a hook portion (212) integrally formed inward from the body (211).

The syringe according to claim 4, wherein an angle between an inner surface (213) of the hook portion (212) and an inner surface (214) of the body (211) is less than 90 degrees, the hook The section (212) has a triangular or other geometric shape.

6. The syringe according to claim 5, wherein a groove (430) is formed inwardly from the outer edge at an end surface (432) of the step (422) toward the needle tip (431)-end, the groove The cross-sectional shape of (430) is a triangular or other mating geometry that mates with the hook (212).

7. The syringe of claim 4, wherein the inner surface (213) of the hook portion (212) The angle between the inner surface (214) of the body (211) is equal to 90 degrees, the cross section of the hook portion (212) is triangular or other geometric shape; the inner surface (213) of the hook portion (212) is made It can be directly hooked on the end surface (432) of the step (422) toward the end of the needle tip (431), thereby pulling the needle cannula (42) together with the needle tube (43) back into the syringe 1 with the push rod (2).

The syringe according to any one of claims 4-7, characterized in that the body (211) of the hook (21) is an elongated plate-like body having a height greater than that of the sealing lock ring (44) Height; the maximum thickness of the section is less than or equal to the wall thickness of the seal lock ring (44).

The syringe according to any of the claims 1 to 8, characterized in that the hook (21) is made of an elastic material.

The syringe according to claim 1, wherein said seal lock ring (44) is an annular body whose outer circumferential surface is a circular cymbal surface which is gradually reduced in diameter from an end opposite to the hook (21).

11. The syringe according to claim 1, wherein the diameter of the front end of the through hole (421) is varied, and is composed of the following five through holes: a cylindrical through hole is formed inward from the front end surface (423). (424), the cylindrical through hole (424) extends inward to form a conical through hole (425), and the conical through hole (425) extends inwardly with a spherical through hole (426), and the spherical through hole (426) is further directed A cylindrical through hole (429) extends inwardly, and a cylindrical through hole (429) extends inward to form a cylindrical through hole (428).

12. The syringe of claim 11 wherein said through hole (428) has a diameter that is the smallest of all of the through holes and that is the same as the outer diameter of the needle (43), both of which are tight fit, spherical The through hole (426) has the same diameter as the cylindrical through hole (424), and the diameter of both ends is the same as the diameter of the small end of the cylindrical through hole (429) and the conical through hole (425), respectively. The diameters of the through holes are smaller than the diameters of other portions of the through holes (421).

13. The syringe according to claim 1, characterized in that said needle holder (11) is a hollow cylinder concentric with the barrel (1), and an internal thread is provided on the inner wall surface (111) of the front end thereof. The inner wall surface (112) of the rear end is a conical surface.

14. The syringe according to claim 1, wherein a hollow cylinder (415) is integrally formed on the end surface of the rear end portion of the needle hub (41) and the needle base (41), the cylinder ( 415) concentric with the needle hub (41), the inner diameter of which is tightly fitted to the outer diameter of the sealing lock ring (44), the height of which is greater than twice the height of the sealing lock ring (44), and the outer cylindrical surface of the cylinder (415) ( 416) is a conical surface that cooperates with the inner wall surface (112) of the rear end of the needle holder (11).

The syringe according to claim 1, characterized in that the mating connection structure of the needle holder (11) and the needle hub (41) is screwed; the needle holder (11) is an internal thread, and the needle holder (41) The external thread or the needle hub (11) is externally threaded, and the needle hub (41) is internally threaded.

16. The syringe according to claim 1, wherein the mating connection structure of the needle holder (11) and the needle holder (41) is an embedded card structure, and the needle holder (11) is an embedded card holder. The needle holder (41) is a latch that cooperates with the bayonet.

17. A syringe according to claim 1 wherein the front end edge of the cavity of the needle hub (41) has a centrally contracted catch (46).

The syringe according to any one of claims 1 to 17, characterized in that a push rod holder having a limit function is provided between the rear end of the push rod (2) and the syringe (1) (6) ).

19. The syringe according to claim 15, wherein the push rod holder (6) is a cylinder having a through hole (61) in the middle, and the push rod holder (6) is disposed on the barrel (1) The outer wall surface (63) of the inner hollow cylinder is a conical surface, and the inner wall surface (12) of the needle cylinder (1) in contact with the conical surface (63) of the push rod holder (6) is also the outer wall surface (63). The mating conical surface, the small end diameter of the inner wall surface (12) is smaller than the large end diameter of the inner wall surface (63), and the push rod support (6) is disposed on the inner wall surface of the hollow cylindrical portion outside the syringe (1) At least one thrust groove (62) is opened, and a thrust boss (22) that cooperates with the thrust groove 62 is disposed on a circumferential surface at a corresponding position of the rear end of the push rod (2).