CN110975065B

CN110975065B - Syringe of anticreep needle

Info

Publication number: CN110975065B
Application number: CN201911192689.1A
Authority: CN
Inventors: 曹苏玲; 宋继兰; 程艳芳; 杨立然; 李良凤; 其他发明人请求不公开姓名
Original assignee: Individual
Current assignee: Cao Suling
Priority date: 2019-11-28
Filing date: 2019-11-28
Publication date: 2021-08-10
Anticipated expiration: 2039-11-28
Also published as: CN110975065A

Abstract

The invention belongs to the field of injectors, and particularly relates to an anti-needle-release injector which comprises an injection tube with an injection head, a piston mechanism, a cylindrical piston A, a hose, a sliding plug mechanism and the like, wherein the injection head on the injection tube is connected with a needle sleeve of a needle head structure through the hose; the invention ensures that the syringe which extracts full liquid medicine can completely inject the liquid medicine in the hose and the syringe into livestock and poultry bodies in the injection process by matching the sliding plug mechanism, the piston mechanism and the piston A, and does not leave more liquid medicine in the hose after the injection is finished; compared with the modification of simply connecting a needle head structure and an injection head in a common injection application by using a hose, after the injection is finished, the hose does not basically leave any liquid medicine, so that the waste of the liquid medicine is greatly reduced, the volume or the length of an injection tube which is increased due to the fact that the defect of the standard injection dosage of the injector caused by the liquid medicine remained in the hose is overcome, the injection cost is reduced, and the flexible operation is convenient.

Description

Syringe of anticreep needle

Technical Field

The invention belongs to the field of syringes, and particularly relates to a syringe capable of preventing needles from falling.

Background

The epidemic prevention work of livestock and poultry is indispensable in livestock breeding, and the injection of liquid medicine is vital as part of the epidemic prevention work; the method of injecting the liquid medicine into the bodies of the livestock and poultry through the injector can quickly and effectively treat the sick livestock and poultry; when the traditional livestock and poultry liquid medicine injector is used for injecting livestock and poultry, the phenomenon of needle falling or needle breaking of the injector which is injecting can be caused by struggle of the livestock and poultry caused by pain, so that the injection work of the livestock and poultry is stopped, and the liquid medicine injection work of the sick livestock and poultry can not be normally completed.

In order to solve the problem of needle release or needle breakage caused by struggle of livestock and poultry during the injection process of the traditional liquid medicine injector, it is necessary to design an injector which can prevent the needle release or the needle breakage from smoothly injecting.

The invention designs an anti-drop syringe to solve the problems.

Disclosure of Invention

In order to solve the defects in the prior art, the invention discloses a needle-drop-preventing injector which is realized by adopting the following technical scheme.

In the description of the present invention, it should be noted that the terms "inside", "outside", "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or orientations or positional relationships that the products of the present invention conventionally use, which are merely for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, or be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used merely to distinguish one description from another, and are not to be construed as indicating or implying relative importance.

An anti-needle-off syringe is characterized in that: the injection device comprises an injection tube with an injection head, a piston mechanism, a cylindrical piston A, an injection rod, a hose, a needle head structure consisting of a needle sleeve and a needle tube, and a sliding plug mechanism, wherein the injection head on the injection tube is connected with the needle sleeve of the needle head structure through the hose; a piston mechanism and a manually driven piston A are hermetically and slidably arranged in the injection cylinder, and the piston mechanism is positioned between the injection hole and the piston A; and the sliding plug mechanism matched with the piston mechanism slides in the hose and the injection head in a sealing way. The inner wall of the injection hole of the injection head is circumferentially provided with a ring groove I communicated with the tail end of the injection hole, and the inner diameter of the ring groove I is equal to that of the hose, so that the stepped sliding plug can smoothly slide into the injection head from the hose without obstacles. And the inner wall of the ring groove I is circumferentially provided with a ring groove B matched with the sliding plug mechanism.

The piston mechanism comprises a cylindrical piston B, a double-headed conical block, a spring A, a sealing ring C, a sliding rod A and a spring B, wherein the piston B with a through hole in the center of the end surface slides in the injection tube in a sealing way; the double-end conical block is matched with the sliding plug mechanism; the side surface of the ring groove J far away from the injection hole is a conical surface C; a ring groove E is circumferentially formed in the conical surface E, far away from the injection hole, of the double-head conical block, and a sealing ring C of the conical surface E is embedded in the ring groove E; the conical surface C is matched with the sealing ring C and the conical surface E; two sliding rods A driven by a conical surface F on the double-end conical block close to the injection hole respectively slide in two sliding grooves A on the inner wall of the annular groove J symmetrically along the radial direction of a section circle of the piston B, and springs B for resetting the sliding rods A are arranged on the two sliding rods A; one end of the two slide bars A, which is out of the piston B, is matched with a ring groove A on the inner wall of the injection hole end of the injection cylinder.

The sliding plug mechanism comprises a cylindrical stepped sliding plug, a sliding rod B, a top block, a wedge-shaped block, a spring C, a limiting block, a sliding rod C and a spring D, wherein the large-diameter part of the stepped sliding plug is in sealed sliding fit with the inner wall of the hose and the inner wall of the injection head; the center of the end face of the small-diameter part of the stepped sliding plug is provided with a sliding chute B which is communicated with a movable groove in the stepped sliding plug; the sliding rod B slides in the sliding groove B along the central axis direction of the stepped sliding plug, one end of the sliding rod B is connected with the wedge-shaped block positioned in the movable groove, and the other end of the sliding rod B is provided with an ejector block matched with the conical tip of the conical surface F; the sliding rod B is provided with a spring C for resetting the sliding rod B; two sliding rods C driven by two inclined planes of the wedge block symmetrically slide in two sliding grooves C on the inner wall of the movable groove along the radial direction of the section circle of the stepped sliding plug respectively, and springs D for resetting the sliding rods C are arranged on the two sliding rods C; two limiting blocks for keeping the spring C pre-stretched are symmetrically arranged on the sliding rod B; a plurality of communicating grooves A communicated with the cylindrical surface of the large-diameter part of the stepped sliding plug are uniformly formed in the circumferential direction on the cylindrical surface of the small diameter of the stepped sliding plug, and a plurality of communicating grooves B communicated with the end surface of the large-diameter cylindrical surface of the stepped sliding plug are formed in the cylindrical surface of the large diameter of the stepped sliding plug; one end of the sliding rod C, which is out of the stepped sliding plug, is provided with a driving inclined plane matched with the edge of the injection hole.

As a further improvement of the technology, one end of the injection tube is provided with a detachable guide ring plate which is in sliding fit with the injection rod, and one end of the injection rod, which is positioned outside the injection tube, is provided with a pressing plate; the cylinder of piston A is gone up the circumference and is opened two annular F that distribute along piston A central axis direction, all imbeds in every annular F and installs and inject the sealed complex sealing ring A of cartridge inner wall. The transition between the inner cylindrical surface of the injection tube and the inner end surface of the injection tube is realized through a conical surface A, the end surface of the piston B close to the injection hole is a conical surface B matched with the conical surface A, and the matching of the conical surface A and the conical surface B ensures that the pressure loss of liquid medicine in the injection tube is small in the injection process of the injector. After the injection of the injector is finished, the guide ring plate can be detached from the injection tube so as to draw out the piston A and the piston mechanism from the injection tube, and the liquid medicine possibly remained in the ring groove J on the piston B can be cleaned, so that the cleaning of the injector for finishing the injection is finished.

As a further improvement of the technology, the end face of the tail end of the injection head is an annular inner conical surface D, when one end of the stepped sliding plug passes through the joint of the hose and the injection head, the conical surface D of the end face of the tail end of the injection head does not form a barrier to the continuous sliding of the sliding plug mechanism, and the stepped sliding plug is guaranteed to slide into the injection head from the hose smoothly.

As a further improvement of the technology, the side wall of the hose is provided with a compensation hole, and an external annular bulge is arranged at the compensation hole; the outer cylindrical surface of the annular bulge is provided with a sealing thread, and the bulge is in thread fit with a sealing cover. After the injector is used for a period of time, the original sealed and matched part is abraded to generate an air leakage phenomenon, so that the air volume between the sliding plug mechanism and the piston mechanism is reduced in an initial state, the sliding plug mechanism is not completely reset after injection is completed, and a space is formed between one end of the stepped sliding plug and the needle sleeve, so that the single injection standard dose of the injector is reduced; when a space is formed between one end of the reset stepped sliding plug and the needle sleeve, the sealing cover can be opened at the moment, so that the interior of the hose is communicated with the atmosphere, one end of the hose needle sleeve is shaken downwards, the sliding plug mechanism moves to the position of the needle sleeve, and the sealing cover is covered again.

As a further improvement of the technology, the center of the end face, far away from the injection hole, of the double-head conical block is provided with a telescopic rod with the diameter smaller than that of the through hole, so that the telescopic rod is ensured not to block the through hole. The telescopic rod is arranged in the middle of the through hole through four fixing plates which are uniformly distributed on the outer side of the telescopic rod in the circumferential direction; the inner rod of the telescopic rod is symmetrically provided with two guide blocks which respectively slide in two guide grooves on the inner wall of the outer rod of the telescopic rod; the spring A is positioned in the outer rod of the telescopic rod; one end of the spring A is connected with the end of the inner rod of the telescopic rod, and the other end of the spring A is connected with the inner wall of the outer rod of the telescopic rod. The telescopic rod with the spring A inside provides a track for the movement of the double-end conical block along the central axis direction of the piston B, and meanwhile, the spring A which plays a role of resetting is always in a compression state due to the cooperation of the guide block inside the telescopic rod and the guide groove, so that the double-end conical block is guaranteed to be always kept pushing the two sliding rods under the action of the spring A, and the piston mechanism is locked between the piston mechanism and the injection tube under the initial state.

As a further improvement of the technology, the outer cylindrical surface of the piston B is circumferentially provided with two annular grooves C which are distributed at intervals along the central axis direction of the piston B, so that air can only enter between the piston A and the piston B through the through hole after entering the injection tube through the injection hole. Sealing rings B which are in sealing fit with the inner wall of the injection cylinder are embedded in the two annular grooves C; the inner wall of each sliding chute A is circumferentially provided with a ring groove D; the two springs B are respectively nested on the corresponding sliding rods A, and the two springs B are respectively positioned in the corresponding ring grooves D; each sliding rod is provided with a tension spring ring A, and the tension spring rings A are positioned in the corresponding ring grooves D; one end of the spring B is connected with the inner wall of the corresponding ring groove D, and the other end of the spring B is connected with the corresponding tension spring ring.

As a further improvement of the technology, the end, matched with the conical surface F, of the double-end conical block, of the sliding rod A is an inclined surface, so that relative sliding between the sliding rod A and the conical surface F is smoother, the pressure of the rod end of the sliding rod A to the conical surface F is reduced, further, the phenomenon that the conical surface F, caused by interaction of the local part of the rod end of the sliding rod A or the edge of the rod end and the conical surface F, of the rod end of the sliding rod A is pressed out of a dent is avoided, and the smoothness of the surface of the conical surface F of the double-end conical block is guaranteed not to be damaged.

As a further improvement of the technology, the inner wall of the chute B is circumferentially provided with a ring groove G; a tension spring ring B is arranged on the sliding rod B and is positioned in the ring groove G; the spring C is nested on the sliding rod B and is positioned in the annular groove G; the spring C is connected with the inner wall of the ring groove G, and the other end of the spring C is connected with the tension spring ring B; the inner wall of each sliding chute C is circumferentially provided with a ring groove H; the two sliding rods C are respectively provided with a pressure spring ring, and the two pressure spring rings are respectively positioned in the corresponding ring grooves H; the two springs D are respectively nested on the corresponding sliding rods C and are respectively positioned in the corresponding annular grooves H; one end of the spring D is connected with the inner wall of the corresponding annular groove H, and the other end of the spring D is connected with the corresponding pressure spring ring. Conical taper grooves are formed in the center of the end face of the top block, and the taper grooves are matched with the taper tips of the upper conical face F of the double-end conical block, so that the double-end conical block is positioned when the top block pushes the double-end conical block, the stress balance of the two ends of the double-end conical block is guaranteed, and the telescopic rod is prevented from being bent under the action of lateral force of the two sliding rods A after being used for a long time.

As a further improvement of the present technology, the spring a and the spring D are both compression springs, and the spring B and the spring C are both extension springs. The diameter of the ring groove J is larger than that of the injection hole, so that the two sliding rods C can be instantly reset under the reset action of the corresponding springs D respectively after entering the injection cylinder, and the reverse movement of the sliding plug mechanism is limited and hindered.

As a further improvement of the technology, the distance between the communicating groove a and the communicating groove B along the central axis direction of the stepped sliding plug is smaller than the width of the ring groove B along the central axis direction of the syringe, so that when the step boundary end surface of the stepped sliding plug meets the end surface of the ring groove I, the part between the communicating groove a and the communicating groove B on the stepped sliding plug along the central axis direction of the stepped sliding plug is located in the ring groove B, and the sealing fit between the stepped sliding plug and the syringe head is released at the time, so that the liquid medicine between the syringe needle structure and the sliding plug mechanism sequentially enters the space between the sliding plug mechanism and the piston mechanism through the communicating groove a, the ring groove B and the communicating groove B.

Compared with the traditional injector, the injector for extracting the full liquid medicine can inject the liquid medicine in the hose and the injection tube into the livestock and poultry body completely in the injection process of the injector for extracting the full liquid medicine through the matching of the sliding plug mechanism, the piston mechanism and the piston A, and the liquid medicine can not be remained in the hose after the injection is finished; compared with the modification of simply connecting a needle head structure and an injection head in a common injection application by using a hose, after the injection is finished, the hose does not basically leave any liquid medicine, so that the waste of the liquid medicine is greatly reduced, the volume or the length of an injection tube which is increased due to the fact that the defect of the standard injection dosage of the injector caused by the liquid medicine remained in the hose is made up is reduced, the injection cost is reduced, and the flexible operation is convenient; compared with the traditional injector, the invention avoids the phenomena of needle drop and needle breakage caused by struggle of livestock and poultry in the injection process under the condition that the volume of the injection tube of the traditional injector is not changed; the invention has simple structure and better use effect.

Drawings

Fig. 1 is a schematic cross-sectional view of the present invention.

Fig. 2 is a schematic cross-sectional view of the hose, syringe, plunger mechanism and plunger a.

Fig. 3 is a schematic cross-sectional view of the hose, the sliding plug mechanism and the needle hub.

FIG. 4 is a schematic view of the needle hub engaging the needle cannula.

Fig. 5 is a schematic cross-sectional view of the wiper mechanism and its associated components.

FIG. 6 is a schematic view of a stepped wiper plug.

Fig. 7 is a schematic cross-sectional view of a stepped wiper plug from two viewing angles.

Fig. 8 is a schematic cross-sectional view from two viewing angles of the injection sleeve.

Fig. 9 is a schematic cross-sectional view of the piston a engaged with an injection rod.

Fig. 10 is a schematic cross-sectional view of the piston mechanism.

Fig. 11 is a schematic sectional view of the piston B and its piston.

Fig. 12 is a schematic cross-sectional view of the double-ended cone block engaged with a telescoping pole.

FIG. 13 is a cross-sectional view of the hose, the sliding plug mechanism, the syringe, the piston B, and the double-headed cone block.

Number designation in the figures: 1. an injection tube; 2. a ring groove A; 3. a ring groove B; 4. a guide ring plate; 5. a piston mechanism; 6. a piston B; 7. a conical surface B; 8. a ring groove C; 9. a through hole; 10. a ring groove J; 11. a conical surface C; 12. a chute A; 13. a ring groove D; 14. a double-ended conical block; 15. a ring groove E; 16. a telescopic rod; 17. an outer rod; 18. a guide groove; 19. a spring A; 20. an inner rod; 21. a guide block; 22. a seal ring C; 23. a slide bar A; 24. a tension spring ring A; 25. a spring B; 26. a seal ring B; 27. a piston A; 28. a ring groove F; 29. a sealing ring A; 30. an injection rod; 31. pressing a plate; 32. a hose; 33. a compensation hole; 34. a protrusion; 35. a sealing cover; 36. an injection head; 37. a needle head structure; 38. a needle sleeve; 39. a needle tube; 40. a sliding plug mechanism; 41. a stepped sliding plug; 42. a communicating groove A; 43. a communicating groove B; 44. a chute B; 45. a ring groove G; 46. a movable groove; 47. a chute C; 48. a ring groove H; 49. a slide bar B; 50. a top block; 51. a conical groove; 52. a wedge block; 53. a spring C; 54. a tension spring ring B; 55. a limiting block; 56. a slide bar C; 57. a compression spring ring; 58. a spring D; 59. an injection hole; 60. a ring groove I; 61. a conical surface A; 62. a conical surface D; 63. a fixing plate; 64. a drive ramp; 65. a conical surface E; 66. and a conical surface F.

Detailed Description

The drawings are schematic illustrations of the implementation of the present invention to facilitate understanding of the principles of structural operation. The specific product structure and the proportional size are determined according to the use environment and the conventional technology.

As shown in fig. 1 and 4, it includes a syringe 1 with an injection head 36, a piston mechanism 5, a cylindrical piston a27, an injection rod 30, a flexible tube 32, a needle structure 37 composed of a needle sheath 38 and a needle tube 39, and a sliding plug mechanism 40, wherein as shown in fig. 1, the injection head 36 on the syringe 1 is connected with the needle sheath 38 of the needle structure 37 through the flexible tube 32; as shown in fig. 1 and 2, the piston mechanism 5 and the manually driven piston a27 are hermetically slid in the syringe 1, and the piston mechanism 5 is located between the injection hole 59 and the piston a 27; a sliding plug mechanism 40 cooperating with the piston mechanism 5 is sealingly slidable in the hose 32 and the injection head 36. As shown in FIG. 8, the inner wall of the injection hole 59 of the injection head 36 is circumferentially provided with a ring groove I60 communicated with the tail end thereof; as shown in fig. 2 and 13, the inner diameter of the annular groove I60 is equal to the inner diameter of the hose 32, so that the stepped sliding plug 41 can slide into the syringe 36 smoothly without hindrance from the hose 32. The inner wall of the ring groove I60 is circumferentially provided with a ring groove B3 matched with the sliding plug mechanism 40.

As shown in fig. 10, the piston mechanism 5 includes a cylindrical piston B6, a double-headed conical block 14, a spring a19, a sealing ring C22, a sliding rod a23, and a spring B25, wherein as shown in fig. 2 and 11, a piston B6 with a through hole 9 formed in the center of the end face is hermetically slid in the syringe 1, the double-headed conical block 14 for closing or opening the through hole 9 moves along the central axis of the piston B6 in a ring groove J10 communicated with the end face of the piston B6 on the inner wall of the through hole 9, and a spring a19 for returning the double-headed conical block 14 is installed on the double-headed conical block; as shown in fig. 13, the double-ended conical block 14 is engaged with the sliding plug mechanism 40; as shown in fig. 2, 10 and 11, the side of the ring groove J10 away from the injection hole 59 is a tapered surface C11; as shown in fig. 2 and 12, the conical surface E65 of the double-ended conical block 14 far away from the injection hole 59 is circumferentially provided with a ring groove E15; as shown in fig. 2, 12 and 13, the ring groove E15 is embedded with the sealing ring C22 of the conical surface E65; the conical surface C11 is matched with the sealing ring C22 and the conical surface E65; as shown in fig. 10, two sliding rods a23 driven by a conical surface F66 close to the injection hole 59 on the double-ended conical block 14 slide symmetrically in two sliding grooves a12 on the inner wall of the ring groove J10 along the radial direction of the cross-sectional circle of the piston B6, and a spring B25 for resetting the two sliding rods a23 is mounted on each sliding rod a 23; as shown in fig. 2, one end of the two slide bars A23, which is provided with a piston B6, is matched with a ring groove A2 on the inner wall of the end of the injection hole 59 of the syringe 1.

As shown in fig. 5, the sliding plug mechanism 40 comprises a cylindrical stepped sliding plug 41, a sliding rod B49, a top block 50, a wedge block 52, a spring C53, a limit block 55, a sliding rod C56 and a spring D58, wherein as shown in fig. 1, 3 and 13, a large-diameter part of the stepped sliding plug 41 is in sealing sliding fit with the inner wall of the hose 32 and the inner wall of the injection head 36; as shown in fig. 6, a slide groove B44 is formed in the center of the end surface of the small diameter portion of the stepped plunger 41, and the slide groove B44 communicates with the movable groove 46 inside the stepped plunger 41; as shown in fig. 5, the sliding rod B49 slides in the sliding slot B44 along the central axis direction of the stepped sliding plug 41, and one end of the sliding rod B49 is connected with the wedge block 52 located in the movable slot 46; as shown in fig. 5 and 13, the other end of the sliding rod B49 is provided with a top block 50 which is matched with the cone tip of the conical surface F66; the sliding rod B49 is provided with a spring C53 for resetting the sliding rod B49; as shown in fig. 5 and 6, two sliding rods C56 driven by two inclined surfaces of the wedge block 52 slide symmetrically in two sliding grooves C47 on the inner wall of the movable groove 46 along the radial direction of the cross-section circle of the stepped sliding plug 41, and a spring D58 for returning the two sliding rods C56 is mounted on each sliding rod C56; two limiting blocks 55 for keeping the spring C53 to be pre-stretched are symmetrically arranged on the sliding rod B49; as shown in fig. 6, a plurality of communication grooves a42 communicating with the cylindrical surface of the large-diameter portion of the stepped plunger 41 are uniformly formed in the cylindrical surface of the small diameter of the stepped plunger 41 in the circumferential direction, and a plurality of communication grooves B43 communicating with the end surface of the large diameter cylindrical surface of the stepped plunger 41 are formed in the cylindrical surface of the large diameter of the stepped plunger 41; as shown in fig. 5 and 13, the end of the slide bar C56 that goes out of the stepped slide plug 41 has a driving bevel 64 that fits the edge of the injection hole 59.

As shown in fig. 1 and 8, a detachable guide ring plate 4 which is in sliding fit with an injection rod 30 is installed at one end of the injection tube 1; as shown in fig. 1 and 9, a pressure plate 31 is mounted at one end of the injection rod 30, which is located outside the injection tube 1; as shown in fig. 9, the cylindrical surface of the piston a27 is circumferentially provided with two ring grooves F28 distributed along the central axis direction of the piston a 27; as shown in fig. 2 and 13, a sealing ring a29 is inserted into each annular groove F28 and is in sealing fit with the inner wall of the syringe barrel 1. As shown in FIG. 8, the inner cylindrical surface of the syringe barrel 1 is transited to the inner end surface of the syringe barrel 1 by a conical surface A61; as shown in FIGS. 2 and 13, the end surface of the piston B6 close to the injection hole 59 is a tapered surface B7 matched with the tapered surface A61, and the matching of the tapered surface A61 and the tapered surface B7 ensures that the pressure loss of the liquid medicine in the syringe barrel 1 is small during the injection process of the syringe. When the injection of the injector is finished, the guide ring plate 4 can be detached from the injection cylinder 1 so as to withdraw the piston A27 and the piston mechanism 5 from the injection cylinder 1, and the liquid medicine possibly remaining in the ring groove J10 on the piston B6 can be cleaned, so that the cleaning of the injector after the injection is finished.

As shown in fig. 8 and 13, the end face of the injection head 36 is an annular inner tapered surface D62, and when one end of the stepped sliding plug 41 passes through the joint between the hose 32 and the injection head 36, the tapered surface D62 of the end face of the injection head 36 does not form an obstacle to the continuous sliding of the sliding plug mechanism 40, thereby ensuring that the stepped sliding plug 41 slides smoothly from the hose 32 into the injection head 36 as a whole.

As shown in fig. 1 and 2, the side wall of the hose 32 is provided with a compensation hole 33, and an external annular protrusion 34 is arranged at the compensation hole 33; the annular projection 34 has a sealing thread on its outer cylindrical surface, and the projection 34 is screw-fitted with a sealing cap 35. After the injector is used for a period of time, the original sealed and matched part is abraded to generate an air leakage phenomenon, so that the air volume between the sliding plug mechanism 40 and the piston mechanism 5 is reduced in an initial state, the sliding plug mechanism 40 is incompletely reset after injection is completed, and a space is formed between one end of the stepped sliding plug 41 and the needle sleeve 38, so that the single injection standard dose of the injector is reduced; when a space is formed between one end of the reset stepped sliding plug 41 and the needle sleeve 38, the sealing cover 35 can be opened at the moment, so that the interior of the hose 32 is communicated with the atmosphere, then one end of the needle sleeve 38 of the hose 32 is shaken downwards, so that the sliding plug mechanism 40 moves to the position of the needle sleeve 38, and then the sealing cover 35 is covered again.

As shown in fig. 10, 12 and 13, the center of the end surface of the double-ended conical block 14 far away from the injection hole 59 is provided with an expansion link 16 with a diameter smaller than that of the through hole 9, so that the expansion link 16 does not block the through hole 9. As shown in fig. 2 and 12, the telescopic rod 16 is installed in the middle of the through hole 9 through four fixing plates 63 uniformly distributed on the outer side of the telescopic rod in the circumferential direction; as shown in fig. 12, two guide blocks 21 are symmetrically installed on the inner rod 20 of the telescopic rod 16, and the two guide blocks 21 respectively slide in the two guide grooves 18 on the inner wall of the outer rod 17 of the telescopic rod 16; the spring A19 is positioned inside the outer rod 17 of the telescopic rod 16; one end of the spring A19 is connected with the rod end of the inner rod 20 of the telescopic rod 16, and the other end is connected with the inner wall of the outer rod 17 of the telescopic rod 16. The telescopic rod 16 with the spring a19 inside provides a track for the movement of the double-ended conical block 14 along the central axis direction of the piston B6, and meanwhile, the cooperation of the guide block 21 inside the telescopic rod 16 and the guide groove 18 enables the spring a19 playing a reset role to be always in a compressed state, so that the double-ended conical block 14 is ensured to always keep pushing the two sliding rods under the action of the spring a19, and the piston mechanism 5 is enabled to be locked with the injection tube 1 in an initial state.

As shown in fig. 11, the outer cylindrical surface of the piston B6 is circumferentially provided with two ring grooves C8 spaced apart from each other along the central axis of the piston B6; as shown in FIG. 2, two ring grooves C8 are located between the slide groove A12 and the piston A27, ensuring that air entering the syringe 1 through the injection hole 59 can only enter between the piston A27 and the piston B6 through the through hole 9. The two ring grooves C8 are embedded with sealing rings B26 which are in sealing fit with the inner wall of the syringe 1; as shown in fig. 11, the inner wall of each sliding chute a12 is circumferentially provided with a ring groove D13; as shown in FIG. 10, two springs B25 are nested on the corresponding slide bar A23, and two springs B25 are located in the corresponding ring grooves D13; each sliding rod is provided with a tension spring ring A24, and the tension spring ring A24 is positioned in the corresponding annular groove D13; one end of the spring B25 is connected with the inner wall of the corresponding ring groove D13, and the other end is connected with the corresponding tension spring ring.

As shown in fig. 10, the end of the slide bar a23 that is engaged with the tapered surface F66 of the double-ended conical block 14 is an inclined surface, so that the relative sliding between the slide bar a23 and the tapered surface F66 is smoother, the pressure of the bar end of the slide bar a23 to the tapered surface F66 is reduced, further, the indentation of the tapered surface F66 caused by the interaction between the local part of the bar end or the edge of the bar end and the tapered surface F66 of the slide bar a23 by the edge of the bar end of the slide bar a23 is avoided, and the surface smoothness of the tapered surface F66 of the double-ended conical block 14 is ensured not to be damaged.

As shown in fig. 7, the inner wall of the sliding groove B44 is circumferentially provided with a ring groove G45; as shown in fig. 5, a tension spring ring B54 is mounted on the sliding rod B49, and a tension spring ring B54 is located in the ring groove G45; spring C53 is nested on slide bar B49, and spring C53 is located in ring groove G45; the spring C53 is connected with the inner wall of the ring groove G45, and the other end of the spring C53 is connected with a tension spring ring B54; as shown in fig. 7, the inner wall of each chute C47 is circumferentially provided with a ring groove H48; as shown in fig. 5, the two sliding rods C56 are each provided with a compression spring ring 57, and the two compression spring rings 57 are respectively located in the corresponding ring grooves H48; the two springs D58 are respectively nested on the corresponding sliding rods C56, and the two springs D58 are respectively positioned in the corresponding ring grooves H48; one end of the spring D58 is connected with the inner wall of the corresponding ring groove H48, and the other end is connected with the corresponding compression spring ring 57; as shown in fig. 5 and 13, the conical tapered groove 51 is formed in the center of the end surface of the top block 50, and the tapered groove 51 is matched with the tapered tip of the upper tapered surface F66 of the double-ended conical block 14, so that the top block 50 pushes the double-ended conical block 14 and positions the double-ended conical block 14, the two ends of the double-ended conical block 14 are balanced in stress, and the telescopic rod 16 is prevented from being bent under the lateral force of the two sliding rods a23 after being used for a long time.

As shown in fig. 5 and 12, the spring a19 and the spring D58 are both compression springs; as shown in fig. 5 and 10, the spring B25 and the spring C53 are both extension springs. The diameter of the ring groove J10 is larger than that of the injection hole 59, which ensures that the two slide bars C56 will return instantly under the action of the corresponding springs D58 respectively after entering the injection cylinder 1 and limit and obstruct the reverse movement of the sliding plug mechanism 40.

As shown in fig. 6 and 13, the distance between the communication groove a42 and the communication groove B43 in the central axis direction of the stepped sliding plug 41 is smaller than the width of the ring groove B3 in the central axis direction of the syringe barrel 1, so that when the step boundary end surface of the stepped sliding plug 41 meets the end surface of the ring groove I60, the part between the communication groove a42 and the communication groove B43 of the stepped sliding plug 41 in the central axis direction of the stepped sliding plug 41 is located in the ring groove B3, and at this time, the sealing engagement between the stepped sliding plug 41 and the syringe head 36 is released, so that the liquid medicine between the needle structure 37 and the sliding plug mechanism 40 sequentially enters between the sliding plug mechanism 40 and the piston mechanism 5 through the communication groove a42, the ring groove B3 and the communication groove B43.

The needle structure 37, barrel 1 and plunger A27 of the present invention are all of the prior art.

The working process of the invention is as follows: in an initial state, as shown in fig. 3, the sliding plug mechanism 40 is located at one end of the needle structure 37 in the hose 32, and a distal end face of the large diameter portion of the stepped sliding plug 41 is in contact with an end face of the needle sheath 38 of the needle structure 37; as shown in fig. 2, spring a19 is pre-tensioned, with the tension spring ring located near the middle of ring groove G45; as shown in fig. 5, the rod ends of the two slide rods C56 located in the movable slot 46 are respectively in contact with the two inclined surfaces of the wedge-shaped block 52; the two stopper blocks 55 are in contact with the side walls of the movable groove 46; as shown in fig. 1, the top block 50 has a certain distance from the end surface of the small diameter portion of the stepped wiper plug 41; both springs D58 are in compression; one end of the two sliding rods C56 is located at the outer limit position of the stepped sliding plug 41, and the distance between the exposed ends of the two sliding rods C56 is slightly larger than the diameter of the injection hole 59, so as to ensure that the two sliding rods C56 cross the injection hole 59 and enter the injection tube 1 to lock the relative position of the sliding plug mechanism 40 and the injection tube 1.

In the initial state, the conical surface B7 on the piston B6 contacts with the conical surface A61 in the syringe barrel 1; the exposed ends of the two slide bars A23 are positioned in a sliding groove A12 on the inner wall of the syringe 1; the two springs B25 are pre-stretched, and the inclined surfaces of the two slide bars A23 are contacted with the conical surface of the double-headed conical block 14 close to the injection hole 59; the double-head conical block 14 is in an open state relative to the through hole 9; a certain distance is reserved between the sealing ring C22 and the conical surface C11; the spring a19 in the telescoping rod 16 is in a compressed state; the end face of the piston a27 abuts against the end face of the piston B6.

When the injection device is required to be used for injecting liquid medicine into livestock and poultry, the needle tube 39 is immersed below the liquid level of the liquid medicine, then the injection rod 30 is pulled through the pressure plate 31, and the injection rod 30 drives the piston A27 to move in the injection tube 1; the movement of the piston A27 causes air located in the hose 32 to enter between the piston A27 and the piston B6 through the through hole 9, the piston A27 gradually moves away from the piston B6; meanwhile, under the action of the external atmospheric pressure, the sliding plug mechanism 40 moves along the hose 32 in the direction of the injection hole 59, and the liquid medicine enters the inner wall space of the hose 32 between the sliding plug mechanism 40 and the needle sleeve 38 through the needle tube 39.

When the driving inclined surfaces 64 of the two slide bars C56 in the sliding plug mechanism 40 meet the edges of the injection hole 59 through the ring groove I60, the edges of the injection hole 59 act on the driving inclined surfaces 64 of the two slide bars C56, so that the two slide bars C56 are retracted into the stepped sliding plug 41; the two sliding rods C56 drive the sliding rod B49 to contract inwards along the sliding groove B44 at the small-diameter end of the stepped sliding plug 41 through the wedge-shaped block 52, and the top block 50 moves synchronously along with the sliding rod B49; meanwhile, the two sliding rods C56 respectively and simultaneously drive the corresponding spring D58 in a pre-compression state to release energy through the corresponding compression spring ring 57, the sliding rod B49 drives the spring C53 to be gradually further stretched and store energy through the tension spring ring B54, and the two limiting blocks 55 are separated from the side wall of the movable groove 46; when the exposed ends of the two sliding rods C56 completely enter the injection hole 59, the top ends of the exposed ends of the two sliding rods C56 are in contact with the inner wall of the injection hole 59, and the top block 50 is just in contact with the end face of the stepped sliding plug 41.

Continued pulling of the piston a27 draws air between the wiper mechanism 40 and the piston B6; when the inner wall of the conical groove 51 on the top block 50 is completely contacted with the conical tip of the double-ended conical block 14, the distance between the side surfaces of the two sliding rods C56 far away from the top block 50 and the inner end surface of the syringe 1 is slightly larger than the distance between the conical surface E65 and the conical surface C11 along the central axis direction of the piston B6, and the distance between the side surfaces of the two sliding rods C56 far away from the top block 50 and the inner end surface of the syringe 1 is equal to the distance between the step junction end surface of the step sliding plug 41 and the end surface of the annular groove I60; continued pulling of the piston a27 draws air between the wiper mechanism 40 and the piston B6; the sliding plug mechanism 40 continues to move, the top block 50 pushes the double-head conical block 14 to move synchronously, the telescopic rod 16 contracts, the spring A19 is further compressed and stores energy, and the double-head conical block 14 gradually closes the through hole 9; the double-head conical block 14 gradually contacts and limits the two sliding rods A23, the two pre-stretched springs B25 respectively drive the two sliding rods A23 to move towards the inside of the piston B6 through the corresponding tension spring rings A24, and the two sliding rods A23 gradually release the fixation of the relative position between the piston B6 and the injection tube 1; when the sealing ring C22 on the double-head conical block 14 contacts with the conical surface C11 and is extruded and deformed, the two sliding rods A23 just release the fixation of the relative position between the piston B6 and the syringe 1, and the through hole 9 is completely sealed by the double-head conical block 14 and the sealing ring C22; since the two sealing rings B26, which engage the respective ring grooves C8, are located between the slide groove a12 and the piston a27, a closed space is formed between the interior of the piston B6 and the stepped plug 41.

The piston A27 is continuously pulled through the pressure plate 31 and the injection rod 30, and the liquid medicine continuously entering the hose 32 through the needle tube 39 pushes the sliding plug mechanism 40 and the piston mechanism 5 to synchronously move relative to the injection tube 1 under the action of the external atmospheric pressure; when the sliding plug mechanism 40 and the piston mechanism 5 synchronously move for a small distance, the driving inclined plane 64 ends of the two sliding rods C56 in the sliding plug mechanism 40 just completely enter the syringe 1 and are respectively and instantly reset under the reset action of the corresponding springs D58, the side surfaces of the two sliding rods C56 far away from the top block 50 are in contact with the inner end surface of the syringe 1 and limit the reverse reset movement of the sliding plug mechanism 40, and the two sliding rods C56 simultaneously release the limit on the wedge-shaped block 52; at this time, the step interface of the stepped sliding plug 41 just contacts with the boundary end face of the ring groove I60 and the injection hole 59, one end of the communicating groove B43 just enters the range of the ring groove B3, the space between the piston B6 and the needle sleeve 38 is not blocked by the stepped sliding plug 41 any more, one end of the two sliding rods a23 which is contracted into the piston B6 abuts against the inner wall of the injection cylinder 1, and further the two sliding rods a23 are ensured to continuously block the through hole 9 through the double-headed conical block 14.

The piston A27 is continuously pulled through the pressure plate 31 and the injection rod 30, and the piston mechanism 5 starts to synchronously move along with the piston A27 under the action of the external atmospheric pressure; the double-head conical block 14 is gradually separated from the top block 50, under the reset action of the spring C53, the spring C53 drives the sliding rod B49 to reset through the tension spring ring B54, and the sliding rod B49 drives the wedge-shaped block 52 and the top block 50 to synchronously reset; the liquid medicine entering the hose 32 enters the space between the piston mechanism 5 and the sliding plug mechanism 40 in the syringe 1 through the communicating groove B43, the ring groove B3 and the communicating groove A42; when the double-end conical block 14 is completely separated from the top block 50, the sliding rod B49 and the wedge block 52 are completely reset relative to the stepped sliding plug 41 under the action of the spring C53, and two inclined surfaces of the wedge block 52 are respectively and simultaneously contacted with the rod ends of the two sliding rods C56; when the required amount of the liquid medicine is sucked into the syringe 1 and the hose 32, the liquid medicine is completely sucked by stopping pulling the pressure plate 31 and the injection rod 30.

Then, the needle structure 37 is lifted to a height higher than that of the injection tube 1, the piston a27 is pushed by the pressure plate 31 and the injection rod 30, and the piston a27 drives the piston mechanism 5 to push the liquid medicine in the injection tube 1 and the hose 32 to remove air in the liquid medicine; the needle tube 39 is then inserted into the target site on the body of the animal and poultry to begin injection.

The piston A27 is pushed to move to the initial position in the injection cylinder 1 by the pressure plate 31 and the injection rod 30, and the piston A27 drives the piston mechanism 5 to move synchronously with the piston A27 by enclosed air; the piston mechanism 5 gradually injects the liquid medicine in the syringe 1 and the hose 32 sequentially through the needle structure 37 into the livestock body, and the liquid medicine in the syringe 1 gradually enters the hose 32 through the communicating groove a42, the ring groove B3 and the communicating groove B43.

When the cone tip of the cone surface F66 of the double-ended cone block 14 completely enters the cone groove 51 on the top block 50, the double-ended cone block 14 synchronously moving with the piston mechanism 5 drives the wedge block 52 to synchronously move through the top block 50 and the sliding rod B49, and the sliding rod B49 contracts and slides relative to the stepped sliding plug 41; the wedge-shaped block 52 gradually releases the restriction on the two slide bars C56, the two slide bars C56 respectively perform retraction movement under the action of the corresponding pre-compressed springs D58; when the top block 50 is contacted with the end face of the stepped sliding plug 41, the exposed ends of the two sliding rods C56 just retract to the diameter range of the injection hole 59; the piston mechanism 5 is continuously pushed to move by the piston A27, and the double-ended conical block 14 which synchronously moves along with the piston mechanism 5 drives the whole sliding plug mechanism 40 to synchronously move through the top block 50; when the rod ends of two sliding rods A23 in the piston mechanism 5 simultaneously enter the range of the ring groove A2 in the injection cylinder 1, the communication groove B43 on the stepped sliding plug 41 is completely separated from the range of the ring groove B3, the stepped sliding plug 41 and the injection head 36 are in sealing fit again, and the rod ends of two sliding rods C56 are positioned in the injection hole 59; at this time, the two sliding rods a23 are respectively reset instantly under the reset action of the corresponding springs B25 and limit the piston mechanism 5 again, the two sliding rods a23 simultaneously release the limitation on the double-headed conical block 14, and the piston mechanism 5 stops moving; the piston A27 is continuously pushed by the pressure plate 31 and the injection rod 30, the piston A27 pushes the double-end conical block 14 by air sealed between the piston A27 and the piston B6, and the double-end conical block 14 continuously pushes the sliding plug mechanism 40 to perform reset movement by the ejector block 50 under the dual actions of the spring A19 and the air between the piston A27 and the piston B6; when the double-ended conical block 14 is completely reset relative to the piston B6, the conical surface F66 is in contact with the inclined surfaces of the inclined surface ends of the two sliding rods A23 again, the telescopic rod 16 is restored to the initial state, and the spring is restored to the initial state; the through hole 9 is completely opened and the tapered surface F66 remains in contact with the inner wall of the tapered groove 51 of the top block 50.

Continuing to push the piston A27, the piston A27 pushes air between the piston A27 and the piston B6 into a sliding groove J in the piston B6 through the through hole 9; the piston A27 pushes the sliding plug mechanism 40 to continue the reset movement through air; with the resetting movement of the sliding plug mechanism 40, the top block 50 is completely separated from the double-head conical block 14; when the two sliding rods C56 are completely separated from the injection hole 59, under the reset action of the spring C53, the sliding rod B49 drives the top block 50 and the wedge block 52 to instantly complete the reset relative to the step sliding plug 41; the wedge block 52 drives the two sliding rods C56 to instantly complete the reset relative to the stepped sliding plug 41, and the two sliding rods C56 respectively recompress the corresponding springs D58 through the corresponding pressure spring rings 57 and make the two springs D58 return to the initial state; when piston a27 returns to the initial position within syringe barrel 1, piston a27 just pushes the plunger mechanism 40 to the initial position by air inside the syringe; in the process that the piston mechanism 5 and the sliding plug mechanism 40 are reset under the pushing of the piston A27, the liquid medicine in the injector is gradually injected into the bodies of the livestock and poultry; after the injection is finished, the needle tube 39 is pulled out.

After the injector is used for a period of time, the original sealed and matched part is abraded to generate an air leakage phenomenon, so that the air volume between the sliding plug mechanism 40 and the piston mechanism 5 is reduced in an initial state, the sliding plug mechanism 40 is incompletely reset after injection is completed, and a space is formed between one end of the stepped sliding plug 41 and the needle sleeve 38, so that the single injection standard dose of the injector is reduced; when a space is formed between one end of the reset stepped sliding plug 41 and the needle sleeve 38, the sealing cover 35 can be opened at the moment, so that the interior of the hose 32 is communicated with the atmosphere, then one end of the needle sleeve 38 of the hose 32 is shaken downwards, so that the sliding plug mechanism 40 moves to the position of the needle sleeve 38, and then the sealing cover 35 is covered again.

In conclusion, the beneficial effects of the invention are as follows: the invention enables the injector which extracts the full liquid medicine to completely inject the liquid medicine in the hose 32 and the injection tube 1 into the livestock and poultry body in the injection process through the matching of the sliding plug mechanism 40, the piston mechanism 5 and the piston A27, and does not leave more liquid medicine in the hose 32 after the injection is finished; compared with the modification of simply connecting the needle head structure 37 and the injection head 36 in the common injection application by using the hose 32, after the injection is finished, the liquid medicine is basically not left in the hose 32, the waste of the liquid medicine is greatly reduced, the volume or the length of the injection tube 1 increased due to the fact that the defect of the standard injection dosage of the injector caused by the residual liquid medicine in the hose 32 is made up is further reduced, the injection cost is reduced, and the flexible operation is convenient; compared with the traditional injector, the invention avoids the phenomena of needle drop and needle breakage caused by struggle of livestock and poultry in the injection process under the condition that the volume of the injection tube 1 of the traditional injector is not changed.

Claims

1. An anti-needle-off syringe is characterized in that: the injection device comprises an injection tube with an injection head, a piston mechanism, a cylindrical piston A, an injection rod, a hose, a needle head structure consisting of a needle sleeve and a needle tube, and a sliding plug mechanism, wherein the injection head on the injection tube is connected with the needle sleeve of the needle head structure through the hose; a piston mechanism and a manually driven piston A are hermetically and slidably arranged in the injection cylinder, and the piston mechanism is positioned between the injection hole and the piston A; the sliding plug mechanism matched with the piston mechanism slides in the hose and the injection head in a sealing way; the inner wall of an injection hole of the injection head is circumferentially provided with a ring groove I communicated with the tail end of the injection hole, and the inner diameter of the ring groove I is equal to that of the hose; the inner wall of the ring groove I is circumferentially provided with a ring groove B matched with the sliding plug mechanism;

the piston mechanism comprises a cylindrical piston B, a double-headed conical block, a spring A, a sealing ring C, a sliding rod A and a spring B, wherein the piston B with a through hole in the center of the end surface slides in the injection tube in a sealing way; the double-end conical block is matched with the sliding plug mechanism; the side surface of the ring groove J far away from the injection hole is a conical surface C; a ring groove E is circumferentially formed in the conical surface E, far away from the injection hole, of the double-head conical block, and a sealing ring C of the conical surface E is embedded in the ring groove E; the conical surface C is matched with the sealing ring C and the conical surface E; two sliding rods A driven by a conical surface F on the double-end conical block close to the injection hole respectively slide in two sliding grooves A on the inner wall of the annular groove J symmetrically along the radial direction of a section circle of the piston B, and springs B for resetting the sliding rods A are arranged on the two sliding rods A; one end of the piston B on the two slide bars A is matched with a ring groove A on the inner wall of the injection hole end of the injection cylinder;

2. The anti-needle-off syringe of claim 1, wherein: one end of the injection tube is provided with a detachable guide ring plate which is in sliding fit with the injection rod, and one end of the injection rod, which is positioned outside the injection tube, is provided with a pressing plate; the cylindrical surface of the piston A is circumferentially provided with two ring grooves F distributed along the central axis direction of the piston A, and a sealing ring A in sealing fit with the inner wall of the injection cylinder is embedded in each ring groove F; the inner cylindrical surface of the injection tube and the inner end surface of the injection tube are transited through a conical surface A, and the end surface of the piston B close to the injection hole is a conical surface B matched with the conical surface A.

3. The anti-needle-off syringe of claim 1, wherein: the end surface of the injection head is an annular inner conical surface D.

4. The anti-needle-off syringe of claim 1, wherein: the side wall of the hose is provided with a compensation hole, and an external annular bulge is arranged at the compensation hole; the outer cylindrical surface of the annular bulge is provided with a sealing thread, and the bulge is in thread fit with a sealing cover.

5. The anti-needle-off syringe of claim 1, wherein: the center of the end surface of the double-end conical block, which is far away from the injection hole, is provided with a telescopic rod with the diameter smaller than that of the through hole; the telescopic rod is arranged in the middle of the through hole through four fixing plates which are uniformly distributed on the outer side of the telescopic rod in the circumferential direction; the inner rod of the telescopic rod is symmetrically provided with two guide blocks which respectively slide in two guide grooves on the inner wall of the outer rod of the telescopic rod; the spring A is positioned in the outer rod of the telescopic rod; one end of the spring A is connected with the end of the inner rod of the telescopic rod, and the other end of the spring A is connected with the inner wall of the outer rod of the telescopic rod.

6. The anti-needle-off syringe of claim 1, wherein: the outer cylindrical surface of the piston B is circumferentially provided with two ring grooves C which are distributed at intervals along the central axis direction of the piston B, and the two ring grooves C are both positioned between the sliding groove A and the piston A; sealing rings B which are in sealing fit with the inner wall of the injection cylinder are embedded in the two annular grooves C; the inner wall of each sliding chute A is circumferentially provided with a ring groove D; the two springs B are respectively nested on the corresponding sliding rods A, and the two springs B are respectively positioned in the corresponding ring grooves D; each sliding rod is provided with a tension spring ring A, and the tension spring rings A are positioned in the corresponding ring grooves D; one end of the spring B is connected with the inner wall of the corresponding ring groove D, and the other end of the spring B is connected with the corresponding tension spring ring.

7. The anti-needle-off syringe of claim 1, wherein: the end of the sliding rod A, which is matched with the conical surface of the double-head conical block close to the injection hole, is an inclined surface.

8. The anti-needle-off syringe of claim 1, wherein: the inner wall of the chute B is circumferentially provided with a ring groove G; a tension spring ring B is arranged on the sliding rod B and is positioned in the ring groove G; the spring C is nested on the sliding rod B and is positioned in the annular groove G; the spring C is connected with the inner wall of the ring groove G, and the other end of the spring C is connected with the tension spring ring B; the inner wall of each sliding chute C is circumferentially provided with a ring groove H; the two sliding rods C are respectively provided with a pressure spring ring, and the two pressure spring rings are respectively positioned in the corresponding ring grooves H; the two springs D are respectively nested on the corresponding sliding rods C and are respectively positioned in the corresponding annular grooves H; one end of the spring D is connected with the inner wall of the corresponding ring groove H, and the other end of the spring D is connected with the corresponding pressure spring ring; the center of the end surface of the top block is provided with a conical taper groove, and the conical taper groove is matched with the taper tip of the upper conical surface F of the double-head conical block.

9. The anti-needle-off syringe of claim 1, wherein: the spring A and the spring D are both compression springs, and the spring B and the spring C are both extension springs; the diameter of the ring groove J is larger than that of the injection hole.

10. The anti-needle-off syringe of claim 1, wherein: the distance between the communicating groove A and the communicating groove B along the central axis direction of the stepped sliding plug is smaller than the width of the ring groove B along the central axis direction of the injection cylinder.