CN203694286U - Safety self-destruction syringe - Google Patents

Abstract

The utility model discloses a safety self-destruction syringe. The safety self-destruction syringe comprises a protective cap, a syringe needle, a barrel and a syringe needle protector. The syringe needle comprises a needle base and a needle tip installed on the needle base. The protective cap is fixed to the syringe needle. The syringe needle is installed at the front end of the barrel through the syringe needle protector. A push rod provided with an O-shaped ring piston is installed in a hollow cavity of the barrel. In this way, the safety self-destruction syringe is formed as a whole. The syringe needle protector comprises a 6:100 Ruehl connector, a protecting arm, a hinge and a buckle, wherein the syringe needle and the barrel are connected together through the 6:100 Ruehl connector, the syringe needle is contained in the protecting arm, and the syringe needle protector is positioned through the hinge and the buckle. The hinge is connected to the position between the outer circular surface at the upper end of the 6:100 Ruehl connector and the bottom surface of the near side end of the protecting arm in an injection molding mode so that the protecting arm can rotate relative to the 6:100 Ruehl connector. The safety self-destruction syringe is simple in structure and easy to operate; after the injection process is completed, the contaminated needle tip is protected, the self-destruction function is achieved, and therefore it can be prevented that a person is punctured and the syringe is used again.

Description

Safety self-destructing syringe

Technical field

This utility model relates to safety self-destructing syringe; be specifically related to a kind of safety self-destructing syringe with needle guard mechanisms, especially can prevent from that syringe needle that the medical apparatus and instruments such as syringe use from meeting accident after use to stab medical care or cleanup crew and syringe and reuse.

Background technology

Use in a large number on the market at present and sell remain traditional disposable syringe, because it does not possess safety and self-destroying function, particularly because accidental puncture, illegal recovery, reusable phenomenon are difficult to wipe out, cause the potential safety hazard in clinical use, brought problem also to harmless treatment thereafter.

In medical practice, use very extensively with the medical apparatus and instruments of sharp-pointed syringe needle, such as syringe, hemostix etc.These medical apparatus and instruments are not only and in medical institutions, are used by professional and process, but also are usually used in the family and processed by layman.

The multiple disposable syringe major part of prior art is being taken apart after packing, outside syringe needle is exposed to, and injects complete, outside syringe needle is exposed to equally, be easy to stab related personnel, cause very large difficulty to medical care or cleanup crew's collection and treatment, this stabbing also can cause bacteria infection; Meanwhile, used disposable syringe is easy to illegally be reclaimed, reuse by lawless person.

In order to prevent the generation of accidental puncture and to reuse, people have proposed the syringe that uses rear syringe needle to retract.Although this syringe has solved the problem of easily stabbing medical personnel's hands, this syringe construction complexity, cost is high, malfunction.

Summary of the invention

The purpose of this utility model is: a kind of safety self-destructing syringe is provided, and simple structure, easy to operate, self-destruction be protected and be completed to safety and environmental protection can to the needle point polluting after injection finishes, and prevents that again scathing and syringe reuse.

Technical solution of the present utility model is: this safety self-destructing syringe comprises helmet, syringe needle, cylindrical shell, push rod and needle guard mechanisms, described syringe needle comprises needle stand and is arranged on the needle point on needle stand, helmet is fixed on syringe needle, syringe needle is arranged on the front end of cylindrical shell by needle guard mechanisms, be arranged in the hollow cavity of cylindrical shell with the push rod of zero type circle piston, entirety forms safety self-destructing syringe; Described needle guard mechanisms comprises 6:100 Rule adaptor that entry needle and cylindrical shell can be linked together, syringe needle can be received in to inner protection arm, can stably needle guard mechanisms be positioned to hinge and the buckle of various desired location; Described hinge injection moulding is connected between 6:100 Rule adaptor upper end periphery and protection arm proximal end bottom surface, and described protection arm is rotated with respect to described 6:100 Rule adaptor.

Wherein, at least two elasticity support claws of symmetrical molding of described barrel front end conehead inner chamber.

Wherein, described push rod connects push rod back segment by push rod leading portion through changeover portion and forms, changeover portion comprises protruding bracing frame and recessed bracing frame, the top molding push-pull ring of push rod leading portion, injection moulding all-in-one-piece grab is established in the end face center of circle of push-pull ring, the frustum that the molding of grab head and elasticity support claw fasten, between the epimere of push-pull ring and hypomere, be provided with the groove that zero type circle piston is installed, the protruding bracing frame of bottom centre's injection mo(u)lding of push rod leading portion, the recessed bracing frame of top injection mo(u)lding of push rod back segment, protruding bracing frame is positioned at recessed bracing frame and connects into Integer push rod through easy breakpoint injection moulding.

Wherein, on described push rod, at least establish four easy breakpoints, easily breakpoint is set in parallel on the coaxial symmetrical blading of push rod, easily and the gap on recessed bracing frame top and protruding bracing frame top, the baseplane of protruding bracing frame at breakpoint place equates with the gap of recessed bracing frame bottom, and gap is within the scope of each easily broken point deformation.

Wherein, described push-pull ring epimere diameter is slightly less than injector cartridge internal diameter, and push-pull ring hypomere diameter equals injector cartridge nozzle diameter, and the end face A of push-pull ring is plane or is the conical surface, determines depending on injector cartridge end shape.

Wherein, described groove is square or for arc, the internal diameter of groove equals zero type circle piston inner diameter, and the width of groove equals zero type circle piston wire diameter, and the degree of depth of groove is slightly larger than the half of zero type circle piston wire diameter.

Wherein, described zero type circle piston is injection molded by medical plastic or medical grade rubber material, and between zero type circle piston and cylinder inboard wall, by zero type circle outer ring surface sealing, zero type circle outer ring surface can be also two seals ring or multiple-sealed ring.

Wherein, described 6:100 Rule adaptor comprises 6:100 Rule screw joint and 6:100 Luer inner conical connector.

Wherein, described hinge comprises the hinge, weakening structure and the V-arrangement shell fragment that form by injection moulding; hinge is symmetrically distributed in V-arrangement shell fragment both sides; between hinge and hinge, be connected by weakening structure injection moulding; V-arrangement shell fragment two ends are connected by weakening structure injection moulding with 6:100 Rule adaptor and protection arm respectively; entirety forms hinge; hinge and 6:100 Rule adaptor, protection arm are one; hinge is a part for 6:100 Rule cone joint or protection arm in other words, its two ends respectively with 6:100 Rule adaptor and fixing the combining of protection arm.

Wherein, described buckle is formed on the proximal end notch of described protection arm; notch two forms outstanding buckle to the radially inside and outside expansion in upper end end; in the time that described protection arm turns to certain position towards the direction of helmet; under the extruding of helmet periphery, there is strain in the protection arm notch at buckle place; make buckle 14 can cross the periphery of helmet and buckle and embrace helmet; prevent from protecting arm arbitrarily to rotate in transportation; the mode combination of described buckle exiting, now described protection arm is positioned at wrapping position.

Before this utility model syringe uses, only need firmly just protection arm to be released a little towards the direction away from helmet, helmet exits draw-in groove; In the time continuing to the protection arm application of force along protection arm away from the direction of motion of helmet; if this power is enough to overcome the resistance of V-arrangement shell fragment in wrapping position distortion, use location when described protection arm can be along the direction away from helmet at the auxiliary lower automatic rotating of V-arrangement shell fragment elastic restoring force until in injection or drawing liquid.

Wherein, protection arm is the arm shape structural member of the cross section Axis Extension along the longitudinal that is roughly " U " font, comprises large U section and little U section, wherein between large and small U section with inclined-plane rounding off, the inwall of large U section is provided with reinforcement, and the notch of little U section is inclined-plane, and two outside axiss of pitch of little U section have extended to form reinforcement simultaneously, and reinforcement has increased the area and intensity of protection arm bottom surface outer wall as power acting surface, has further also increased friction with anti-skidding, in the time that protection arm turns to complete protective position, syringe needle enters into the inside of protection arm through the opening of overprotection arm, in order further to guarantee that syringe needle can not depart from from protection arm, protection arm also comprises three rightabout agnail members that along bottom land, angular direction extended certain distance formation from the medial wall notch of little U section, these three agnail members are along longitudinal layout of little U section, make their " thorn " relatively staggered, by this staggered relative layout, pin guides in the space that enters three agnail members and little U section bottom land easily, and lived by agnail member " hook ", thereby remain in this space in the mode that can not exit, described protection arm is in complete protective position.

The utlity model has following advantage:

1, hook structure of the present utility model is more simple, has simplified the manufacture of mould, can better meet the high-precision that adds man-hour, provides cost savings.

2, zero type circle piston structure of the present utility model is simple, reduced make the cost of raw material of piston and with medicinal liquid contact area, piston is greatly reduced, the safer environmental protection of product to the pollution of medicinal liquid; And relatively little with the contact surface of injector cartridge inwall, the frictional resistance correspondingly and between simplified inwall is less, make push rod push-and-pull light.

3, push rod of the present utility model each easy breakpoint in the time of injection is stressed evenly, distortion simultaneously, end face in deformation range convex bracing frame baseplane and recessed bracing frame top, protruding bracing frame top and recessed bracing frame bottom plane is collided, each easy breakpoint can not rupture, can not cause easy-to-draw point while pushing away liquid to rupture in advance, after injection, push rod, backward when withdrawing, can be broken along easy breakpoint, push rod cannot be reused, reach self-destruction.

4, needle guard mechanisms of the present utility model can prevent the accidental puncture accident that the medical apparatus and instruments such as syringe use rear syringe needle to cause reliably, and simple in structure, cost is low, and ordinary syringe can be general, installs additional conveniently; In transportation and use procedure, can stably protection arm be positioned to the position of various hope.

Accompanying drawing explanation

Fig. 1 is that this utility model safety self-destructing syringe is packed the schematic diagram while use, wherein protects arm to be positioned at wrapping position.

Fig. 2 is the cutaway view of Fig. 1.

Cutaway view when Fig. 3 is the injection of this utility model safety self-destructing syringe drawing liquid, wherein protects arm to be positioned at use location.

Fig. 4 is that the push rod A-A of Fig. 3 is to cross section enlarged drawing.

Fig. 5 is the push rod B place partial enlarged drawing of Fig. 3.

Fig. 6 is the another kind of form of the zero type circle piston of Fig. 5.

Fig. 7 is the safe schematic diagram after the injection of this utility model safety self-destructing syringe, wherein protects arm to be positioned at complete protective position.

Fig. 8 is the cutaway view of the complete state of this utility model safety self-destructing syringe safety self-destruct.

Fig. 9 is the front view of the needle guard mechanisms of Fig. 1.

Figure 10 is the dorsal view of Fig. 9.

Figure 11 is the top view of Fig. 9.

Figure 12 is that the E-E of Figure 10 is to cut-away view.

In figure: 1 needle guard mechanisms, 2 helmets, 3 syringe needles, 4 cylindrical shells, 5 push rods, 6 zero type circle pistons, 11 6:100 Rule adaptors, 111 6:100 Rule screw joints, 112 6:100 Luer inner conical connectors, 12 protection arms, 121 little U sections, 122 large U sections, 123 reinforcements, 124 agnails, 13 hinges, 131 hinges, 132 weakening structure, 133 V-arrangement shell fragments, 14 buckles, 31 needle stands, 32 needle points, 41 elasticity support claws, 51 push rod leading portions, 52 push rod back segments, 53 protruding bracing frames, 54 recessed bracing frames, 55 easy breakpoints, 56 push-pull rings, 57 grabs, 58 grooves, C push-pull ring end face, D nozzle internal diameter, F zero type circle outer ring surface, d1 zero type circle piston inner diameter, d2 zero type circle piston wire diameter, d3 push-pull ring epimere diameter, d4 push-pull ring hypomere diameter, d5 groove internal diameter.

The specific embodiment

For ease of understanding, referring to accompanying drawing, embodiment of the present utility model is described in further detail.

Referring to Fig. 1,2, this safety self-destructing syringe comprises helmet 2, syringe needle 3, cylindrical shell 4, push rod 5 and needle guard mechanisms 1, described syringe needle 3 comprises needle stand 31 and is arranged on the needle point 32 on needle stand, helmet is fixed on syringe needle 3, syringe needle 3 is arranged on the front end of cylindrical shell 4 by needle guard mechanisms 1, be arranged in the hollow cavity of cylindrical shell 4 with the push rod 5 of zero type circle piston 6, entirety forms safety self-destructing syringe; Described needle guard mechanisms 1 comprises 6:100 Rule adaptor 11 that syringe needle 3 and cylindrical shell 4 can be linked together, syringe needle can be received in to inner protection arm 12, can stably needle guard mechanisms be positioned to hinge 13 and the buckle 14 of various desired location; Described hinge 13 is connected between 6:100 Rule adaptor 11 upper end peripheries and protection arm 12 proximal end bottom surfaces, and described protection arm 12 can be rotated with respect to described 6:100 Rule adaptor 11.

Referring to Fig. 3, at least two elasticity support claws 41 of symmetrical molding of described cylindrical shell 4 front end conehead inner chambers.

Referring to Fig. 3, 4, 8, described push rod 5 connects push rod back segment 52 by push rod leading portion 51 through changeover portion and forms, changeover portion comprises protruding bracing frame 53 and recessed bracing frame 54, the top molding push-pull ring 56 of push rod leading portion 51, injection moulding all-in-one-piece grab 57 is established in the end face center of circle of push-pull ring 56, between the epimere of push-pull ring and hypomere, be provided with the groove 58 that zero type circle piston 6 is installed, the protruding bracing frame 53 of bottom centre's injection mo(u)lding of push rod leading portion 51, the recessed bracing frame 54 of top injection mo(u)lding of push rod back segment 52, protruding bracing frame 53 is positioned at easy breakpoint 55 injection mouldings of recessed bracing frame 54 warp and connects into Integer push rod 5.

Referring to Fig. 3,4,8, on described push rod 5, at least establish four easy breakpoints 55, easily breakpoint 55 is set in parallel on the coaxial symmetrical blading of push rod 5, easily the baseplane of protruding the bracing frame 53 and gap a on recessed bracing frame 54 tops and protruding bracing frame 53 tops at breakpoint 55 places equates with the gap b of recessed bracing frame 54 bottoms, and gap is within the scope of each easily broken point deformation.

Referring to Fig. 3,5, described push-pull ring epimere diameter d 3 is slightly less than cylindrical shell nozzle inner diameter D, and push-pull ring hypomere diameter d 4 equals cylindrical shell nozzle inner diameter D, and push-pull ring end face C looks the decision of injector cartridge end shape for plane or is curved surface.

Referring to Fig. 5, described groove 58 is square or for arc, the internal diameter of groove equals zero type circle piston inner diameter d1, and the width of groove equals zero type circle piston wire diameter d2, and the degree of depth of groove is slightly larger than the half of zero type circle piston wire diameter d2.

Referring to Fig. 5,6, described zero type circle piston 6 is injection molded by medical plastic or medical grade rubber material, and between zero type circle piston 6 and cylindrical shell 4 inwalls, by zero type circle outer ring surface F sealing, zero type circle outer ring surface F can be also two seals ring or multiple-sealed ring.

Referring to Fig. 2, described 6:100 Rule adaptor 11 comprises 6:100 Rule screw joint 111 and 6:100 Luer inner conical connector 112.

Referring to Fig. 2, 3, described hinge 13 comprises the hinge 131 forming by injection moulding, weakening structure 132 and V-arrangement shell fragment 133, hinge 131 is symmetrically distributed in V-arrangement shell fragment 133 both sides, between hinge 131, connect by weakening structure 132 injection mouldings, V-arrangement shell fragment 133 two ends are connected by weakening structure 132 injection mouldings with 6:100 Rule adaptor 11 and protection arm 12 respectively, entirety forms hinge 13, hinge 13 and 6:100 Rule adaptor 11, protection arm 12 is one, hinge 13 is parts of 6:100 Rule cone joint 112 or protection arm 12 in other words, its two ends respectively with 6:100 Rule adaptor 11 and 12 fixing the combining of protection arm.

Referring to Fig. 2; described buckle 14 is formed on the proximal end notch of described protection arm 12; notch two forms outstanding buckle 14 to the radially inside and outside expansion in upper end end; in the time that described protection arm 12 turns to certain position towards the direction of helmet 2; under the extruding of helmet 2 peripheries, there is strain in the protection arm notch at buckle 14 places; make buckle 14 can cross the periphery of helmet 2 and buckle and embrace helmet 2; prevent from protecting arm arbitrarily to rotate in transportation; the mode combination of described buckle exiting, now described protection arm is positioned at wrapping position.

Referring to Fig. 3, before using, this utility model syringe only needs firmly just protection arm 12 to be released a little towards the direction away from helmet 2, and helmet 2 exits draw-in groove; In the time continuing to protection arm 12 application of force along protection arm 12 away from the direction of motion of helmet 2; if this power is enough to overcome the resistance of V-arrangement shell fragment 133 in wrapping position distortion, use location when described protection arm 12 can be along the direction away from helmet 2 at the auxiliary lower automatic rotating of V-arrangement shell fragment 133 elastic restoring forces until in injection or drawing liquid.

Referring to Fig. 8～12, protection arm 12 is arm shape structural members of the cross section Axis Extension along the longitudinal that is roughly " U " font, comprises large U section 122 and little U section 121, wherein between large and small U section with inclined-plane rounding off, the inwall of large U section 122 is provided with reinforcement 123, the notch of little U section 121 is inclined-plane, two outside axiss of pitch of little U section have extended to form reinforcement 123 simultaneously, and reinforcement 123 has increased the area of protection arm 12 bottom surface outer walls as power acting surface, further also increases friction with anti-skidding, in the time that protection arm 12 turns to complete protective position, syringe needle 3 enters into the inside of protection arm 12 through the opening of overprotection arm, in order further to guarantee that syringe needle 3 can not depart from from protection arm 12, protection arm 12 also comprises three rightabout agnails 124 that along bottom land, angular direction extended certain distance formation from the medial wall notch of little U section 121, these three agnails 124 are along longitudinal layout of little U section 121, make their " thorn " relatively staggered, by this staggered relative layout, needle point 32 guides in the space that enters three agnails and little U section 121 bottom lands easily, and lived by agnail " hook ", remain in this space in the mode that can not exit, now described protection arm 12 is positioned at complete protective position.

Referring to Fig. 1～8, before this utility model syringe drawing liquid, first protection arm 12 is dialed to use location, and pluck helmet 2, when push rod 5 inwardly pushes away liquid when complete, grab 57 just enters in elasticity support claw 41, elasticity support claw 41 falls in the agnail groove of grab 57 grab 57 is locked, and grab 57 is prevented from drawing back; After injection, first protection arm 12 is dialed to the complete protective position of syringe needle 3, then push rod 5 is backward when withdrawing, and easily breakpoint 55 is pulled off, and push rod leading portion 51 is left in cylindrical shell 4, and push rod back segment 52 is drawn out, thereby push rod 5 cannot be reused, and reaches self-destruction.

Above with reference to accompanying drawing, this utility model is carried out to concrete description.But, it should be appreciated by those skilled in the art that specific descriptions are above only the character of giving an example, for illustrative object, be not for limiting protection domain of the present utility model.Have benefited from instruction of the present utility model; those skilled in the art can make various modification, modification or replacement to above-mentioned specifically described embodiment as the case may be in the situation that not exceeding this utility model protection domain, and these modification, modification or replacement fall into protection domain of the present utility model.

Claims (10)

1. safety self-destructing syringe, it is characterized in that: this safety self-destructing syringe comprises helmet (2), syringe needle (3), cylindrical shell (4), push rod (5) and needle guard mechanisms (1), described syringe needle (3) comprises needle stand (31) and is arranged on the needle point (32) on needle stand, helmet is fixed on syringe needle (3), syringe needle (3) is arranged on the front end of cylindrical shell (4) by needle guard mechanisms (1), push rod (5) with zero type circle piston (6) is arranged in the hollow cavity of cylindrical shell (4), entirety forms safety self-destructing syringe, described needle guard mechanisms (1) comprises 6:100 Rule adaptor (11) that syringe needle (3) and cylindrical shell (4) can be linked together, syringe needle can be received in to inner protection arm (12), the hinge (13) that can stably needle guard mechanisms be positioned to various desired location and buckle (14), described hinge (13) is connected between 6:100 Rule adaptor (11) upper end periphery and protection arm (12) proximal end bottom surface, and described protection arm (12) can be rotated with respect to described 6:100 Rule adaptor (11).

2. safety self-destructing syringe according to claim 1, is characterized in that: at least two elasticity support claws of symmetrical molding (41) of described cylindrical shell (4) front end conehead inner chamber.

3. safety self-destructing syringe according to claim 1, it is characterized in that: described push rod (5) connects push rod back segment (52) by push rod leading portion (51) through changeover portion and forms, changeover portion comprises protruding bracing frame (53) and recessed bracing frame (54), push rod leading portion (51) top molding push-pull ring (56), injection moulding all-in-one-piece grab (57) is established in push-pull ring (56) end face axle center, between the epimere of push-pull ring and hypomere, be provided with the groove (58) that zero type circle piston (6) is installed, the protruding bracing frame of bottom centre's injection mo(u)lding (53) of push rod leading portion (51), the recessed bracing frame of top injection mo(u)lding (54) of push rod back segment (52), protruding bracing frame (53) is positioned at recessed bracing frame (54) and connects into Integer push rod (5) through easy breakpoint (55) injection moulding.

4. safety self-destructing syringe according to claim 3, it is characterized in that: on described push rod (5), at least establish four easy breakpoints (55), easily breakpoint (55) is set in parallel on the coaxial symmetrical blading of push rod (5), easily protruding bracing frame (53) baseplane at breakpoint (55) place equates with the gap of recessed bracing frame (54) bottom with gap and protruding bracing frame (53) top on recessed bracing frame (54) top, and gap is within the scope of each easily broken point deformation.

5. safety self-destructing syringe according to claim 3, it is characterized in that: described push-pull ring epimere diameter (d3) is slightly less than cylindrical shell nozzle internal diameter (D), push-pull ring hypomere diameter (d4) equals cylindrical shell nozzle internal diameter (D), and push-pull ring end face (C) is looked the decision of injector cartridge end shape for plane or is curved surface; Described groove (58) is square or is arc, the internal diameter (d5) of groove equals zero type circle piston inner diameter (d1), the width of groove equals zero type circle piston wire diameter (d2), and the degree of depth of groove is slightly larger than the half of zero type circle piston wire diameter (d2).

6. safety self-destructing syringe according to claim 1, it is characterized in that: described zero type circle piston (6) is injection molded by medical plastic or medical grade rubber material, between zero type circle piston (6) and cylindrical shell (4) inwall, by zero type circle outer ring surface (F) sealing, zero type circle outer ring surface (F) can be also two seals ring or multiple-sealed ring.

7. safety self-destructing syringe according to claim 1, is characterized in that: described 6:100 Rule adaptor (11) comprises 6:100 Rule screw joint (111) and 6:100 Luer inner conical connector (112).

8. safety self-destructing syringe according to claim 1, it is characterized in that: described hinge (13) comprises the hinge (131) forming by injection moulding, weakening structure (132) and V-arrangement shell fragment (133), hinge (131) is symmetrically distributed in V-arrangement shell fragment (133) both sides, between hinge (131), connect by weakening structure (132) injection moulding, V-arrangement shell fragment (133) two ends are connected by weakening structure (132) injection moulding with 6:100 Rule adaptor (11) and protection arm (12) respectively, entirety forms hinge (13), hinge (13) and 6:100 Rule adaptor (11), protection arm (12) is one, hinge (13) is a part for 6:100 Rule cone joint (11) or protection arm (12) in other words, its two ends respectively with 6:100 Rule adaptor (11) and fixing the combining of protection arm (12).

9. safety self-destructing syringe according to claim 1, it is characterized in that: described buckle (14) is formed on the proximal end notch of described protection arm (12), notch two forms outstanding buckle (14) to the radially inside and outside expansion in upper end end, in the time that described protection arm (12) turns to certain position towards the direction of helmet (2), under the extruding of helmet (2) periphery, there is strain in the protection arm notch at buckle (14) place, make buckle (14) can cross the periphery of helmet (2) and buckle and embrace helmet (2), prevent from protecting arm arbitrarily to rotate in transportation, the mode combination of described buckle exiting.

10. safety self-destructing syringe according to claim 1, it is characterized in that: protection arm (12) is that cross section is the arm shape structural member of the Axis Extension along the longitudinal of " U " font, comprise large U section (122) and little U section (121), wherein between large and small U section with inclined-plane rounding off, the inwall of large U section (122) is provided with reinforcement (123), the notch of little U section (121) is inclined-plane, two outside axiss of pitch of little U section have extended to form reinforcement (123) simultaneously, reinforcement (123) has increased the area of protection arm (12) bottom surface outer wall as power acting surface, further also increases friction with anti-skidding, in the time that protection arm (12) turns to complete protective position, syringe needle (3) enters into the inside of protection arm (12) through the opening of overprotection arm, in order further to guarantee that syringe needle (3) can not depart from from protection arm (12), protection arm (12) also comprises three the rightabout agnails (124) that along bottom land, angular direction extended certain distance formation from the medial wall notch of little U section (121), these three agnails (124) are along longitudinal layout of little U section (121), make their " thorn " relatively staggered, by this staggered relative layout, needle point (32) guides in the space that enters three agnails and little U section (121) bottom land easily, and lived by agnail " hook ", remain in this space in the mode that can not exit.