CN200957235Y - Internally-contracted automatic safety syringes - Google Patents

Abstract

An automatically retractable safety injector, which is composed of a syringe, a neilsbed with a puncture needle tube, a handspike with a hollow tube, a spring and a piston; elastic claws of the neilsbed are set up on a step surface of an inner hole set up behind the neilsbed; after injection, pushing the handspike forward again and a semicircular flange of a head face of the piton draws back along a transition slope at the front end of the syringe so as to detach the flange of neilsbed away from a sidestep bearing surface of the syringe, and then the claw tine located at the front end of the neilsbed punctures and incises a piston film ring by means of the spring, and then the broken piston film ring falls into the hollow tube of the handspike. The patent injector has the advantages of that the structure is simple with a reliable orientation and bearing; meantime, owing to has a low pollution on liquid medicine, the invention has a high safety with a small impact on patients, at the same time, as the manufacturing precision is not high and the assembly is easy with a low cost, so the utility model is applicable for a mass production.

Description

A kind of inner contraction type automatic safety syringe

One. technical field:

The present invention relates to a kind of safety injector, after particularly a kind of injection finished, syringe needle can retract to the safety injector in the push rod automatically, belonged to medical instruments field.

Two. background technology:

In order to reduce because of contaminated needle point thorn, to scratch and infect the danger of pernicious infectious disease (as: hepatitis, acquired immune deficiency syndrome (AIDS) etc.), many safety injectors that can protect have been invented with the back syringe needle.

Such safety injector has a lot of patents at present, but most some potential safety hazards that exist, particularly the part that contacts with medicinal liquid is too much, very easily causes drug contamination.And reduce these contaminations, tend to significantly increase production cost; The other design is very high to the physical dimension required precision of part, causes the bulk article performance to be difficult to be consistent.As the automatic safety injector of retraction of patent 200220028888.8 disclosed a kind of syringe needles, there are 7 parts to contact (whole parts comprise that the pin medicated cap is 10) with medicinal liquid, to guarantee obviously to contact that part all do not stain is very difficult with medicinal liquid.Before this external injection terminal point, the push rod center piston will be slided to endoporus, and push rod front end tubular push rod will push away the o RunddichtringO sealing and restriction needle stand ejected position simultaneously.Obviously, this makes the power of injecting that bigger increase be arranged, and this power of injecting variation tends to make by the injector and do not feel well.In addition, start the safety clearance, thereby the accurate control of injected dose is brought some inconvenience because piston nose must stay.These problems, such syringe has often, directly has influence on the safety and the production cost of the use of product.The present invention proposes the safety injector design that a kind of new syringe needle can bounce back automatically for this reason, in the hope of addressing the above problem preferably.

Three. summary of the invention:

The objective of the invention is: a kind of new syringe needle inner contraction type automatic safety syringe is provided, reaches simple for structure, safe in utilization easy, thrust stable, easily manufactured, purpose that cost is low.

The object of the present invention is achieved like this: a kind of automatic safety syringe, comprise syringe (1), the push rod (2) of being with center cavity, piston (3), the needle stand (4) of being with injection needle, o RunddichtringO (5), reach spring (6), it is characterized in that:

The one transition conical surface (114) is arranged between the endoporus (121) of the endoporus of the preceding cervical region of described syringe (1) (11) and syringe main body (21), be provided with the positioning table terrace (113) that a diameter is a bit larger tham the transition conical surface (114) end diameter at the transition conical surface (114) front end, sealing surface (112) is established at the endoporus of cervical region (11) middle part before the syringe, and its diameter is less than the described transition conical surface (114) end diameter;

It is semicircular bulge loop (32) that there is a cross section at piston (3) front end face middle part, its centrage is at the aforementioned transition circle conical surface (114) medium position, described bulge loop (32) is connected with piston (3) front end face middle part by interior thin film ring (34), and bulge loop (32) is connected with the cylindrical outer wall (31) of piston (3) by outer film ring (35);

Needle stand (4) is made up of the preceding face of cylinder (43), O-ring cylinder (44) and tubular rear portion (45), and the step between the described less preceding face of cylinder (43) and the bigger O-ring cylinder (44) is spring-loaded face (442); One step locating surface (452) is arranged on the described tubular rear portion (45), can overlap with the positioning table terrace (113) on the cervical region before the aforementioned syringe, endoporus (453) rearward end at described needle stand tubular rear portion (45) is an internal taper hole (454), and internal taper hole (454) intersects the formation orifice with the periphery at tubular rear portion (45); Establish plural groove (455) on the whole tubular rear portion (45), make tubular rear portion (45) be divided into several localised puncture pawls (451), and make it have certain elasticity.

The center of push rod (2) is a hollow cylinder (21), its internal diameter is slightly larger than the external diameter of aforementioned needle stand (4), front cylinder (211) external diameter on the hollow cylinder (21) is less than the above-mentioned syringe transition conical surface (114) outside diameter, and contacts with the inwall of the bulge loop (32) of above-mentioned piston.

Groove (455) on the described tubular rear portion (45) is the oblique groove that is shunk by the rear end forward end, so that described localised puncture pawl (451) front end forms sharp-pointed dentation.

Disk (214) before the preceding cylindrical shell of described push rod (2) (211) cylindrical is provided with one, its diameter is slightly less than piston inner hole (37) diameter, and its thickness is less than 1 ~ 5 millimeter of piston inner hole (37) degree of depth.

There is a nose projection (33) described piston (3) front portion, and its external diameter is less than aforementioned needle stand tubular rear portion (45) endoporus (453) diameter, and its length is less than endoporus (453) degree of depth; Link to each other by thin film ring (34) in described between nose projection (33) root and the described semicircle ring-type projection (32).

Described O-ring cylinder (44) is provided with seal groove (441), and described o RunddichtringO (5) is installed in the sealing groove (441); The preceding cervical region of described syringe (1) is equipped with a plug (7), and a spring-loaded face (72) is arranged in the endoporus of plug (7); Described spring (6) is installed between the spring-loaded face (442) of aforementioned spring-loaded face (72) and needle stand (4) front end.

In another kind of embodiment, be provided with a closure gasket groove (115) in the preceding cervical region of described syringe (1) (11), described o RunddichtringO (5) is installed in the sealing annular groove (115), and the inner headed face of o RunddichtringO (5) closely contacts with surface, the preceding face of cylinder of needle stand (43); Described spring (6) is installed between the spring-loaded face (442) on o RunddichtringO (5) and the needle stand.

In another embodiment, the preceding cervical region of described syringe (1) (11) endoporus front portion is a stepped hole: be made up of the step surface (118) between less front step hole (116) and bigger backward step hole (117) and pro-, the backward step hole; The diameter in described front step hole (116) is greater than the preceding face of cylinder of needle stand (4) (43) diameter, and described backward step hole (117) slightly larger in diameter is in needle stand O-ring cylinder (44) diameter; Described spring (6) is placed between above-mentioned step surface (118) and the needle stand spring-loaded face (442).

Cross section, described piston (3) front end face middle part is semicircular bulge loop (32), also can be made up of the hemispherical projections more than 3 (321).

As can be seen: owing to needle stand is to utilize step surface on its rear portion localised puncture pawl to contact with the corresponding positioning table terrace of syringe to locate, thereby good stability, anti-puncture force is strong.

The transition conical surface at syringe step locating surface rear portion, E bulge loop good and on the piston nose face contacts, owing to all have the thin film ring to link to each other between bulge loop and piston central nose shape cylinder and the outer wall, this had not only guaranteed the seal request of syringe but also had made the bulge loop can be easier with respect to the displacement forward of other parts of piston.Nose shape cylinder on the piston can effectively reduce the residual quantity of syringe.

The push rod front portion is the cylindrical tube body structure, and the endoporus of tube is slightly larger than the maximum outside diameter (positioning step external diameter) of needle stand, and assembling rear push-rod front end face contacts with the inwall of piston bulge loop.On the anterior cylindrical tube periphery of push rod former and later two disks are arranged, preceding disk external diameter is slightly less than the piston inner hole diameter, can match with piston cavity, and its thickness is less than piston cavity length; The rear disk external diameter is slightly less than the syringe diameter of bore, and its front is a circular arc, and the rear end is a vertical.The piston rear wall is sandwiched between the above-mentioned forward and backward disk.

There is a resistance ring syringe endoporus rear end, and its internal diameter is less than the syringe diameter of bore.

Push rod barrel length is suitable with needle stand (together with the injection needle body) length at least, and there are two pairs of vertical relatively wing plates the cylindrical shell outside, and the overall dimensions of wing plate is less than above-mentioned syringe resistance ring internal diameter.

Before the use, needle stand is under the effect of spring force, and the step surface on its rear portion localised puncture pawl contacts with the corresponding positioning table terrace of syringe and is positioned in the anterior endoporus of syringe.Piston also is in the front position, and the bulge loop on it contacts with the syringe transition conical surface, the pointed tooth on the localised puncture pawl of needle stand rear portion also with piston on the thin film loop contacts.

Because after the syringe of the present invention assembling, piston and no gap, syringe bottom, it is identical with ordinary syringe that the basic injection of this syringe is operated, promptly not only easy to operate and make the accurate control of injected dose easier.After injection is finished, as long as continue to make the push rod reach, then the rear disk on the push rod promotes the reach of piston rear portion, piston cylinder shape outer wall is compressed, the anterior piston bulge loop that promotes synchronously of push rod tubular moves forward, under the guiding of the syringe transition conical surface, bulge loop also moves to the syringe center simultaneously, thereby there is certain elastic localised puncture pawl inwardly to shrink on the compressing needle stand, when the supporting station terrace on the disengaging of the step surface on the localised puncture pawl syringe, then needle stand is released, under spring action, move backward, thin film on pointed tooth on it the cutting piston and with its fracture, because set spring force is much larger than the cutting tearing strength of piston thin film, thereby torn rapidly at spring force effect lower piston thin film, then needle stand under spring action with the piston nose type projection that is torn, enter into push rod front end tubular cavity together, and realize the automatic retraction of needle point.

Because spring length is greater than needle length, thereby needle point can not stretch out outside the syringe once more, and because the rear disk external diameter on the push rod greater than the resistance ring internal diameter at syringe rear portion, can not pull out push rod from syringe, thereby avoided the generation of pin evil preferably.When particularly on push rod, being shaped on the weak bonding pad of easy fracture.

Owing to make the active force of needle stand constraint relief vertical with constraint direction, and meet the leverage principle, thereby to make the required active force of needle stand constraint relief be less, this makes and starts retraction and operate light.

The part number of safety injector of the present invention less (5 ~ 7) in addition, and have only 3 parts to contact with injection, thereby not only the contamination to medicinal liquid is few, the injection safety height; And production cost is low.

From the above description as can be seen: safety injector of the present invention preferably resolves the common issue with that present similar safety injector exists, and has bigger practical value.

Four. description of drawings:

Fig. 1 is the structural representation of inner contraction type automatic safety syringe of the present invention

Fig. 2 is the partial enlarged drawing of Fig. 1

Fig. 3 is that safety injector of the present invention extracts the medicinal liquid sketch map

Fig. 4 is that safety injector injection of the present invention finishes sketch map

Fig. 5 ~ 6th, safety injector of the present invention start automatic cam mechanism sketch map

Fig. 7 is that the sketch map that syringe needle bounces back is fully realized in safety injector injection of the present invention back

Fig. 8 is the another kind of embodiment of inner contraction type automatic safety syringe of the present invention

Fig. 9 is another embodiment of inner contraction type automatic safety syringe of the present invention

Figure 10 is the another kind of structural representation of the bulge loop on the safety injector piston of the present invention

Marginal data:

1. syringe: cervical region 111 mating holes 112 sealing surfaces 113 positioning steps before 11

117 backward step holes, the 114 transition conical surface 115 inner seal ring grooves, 116 front step holes

118 step surfaces, 12 syringe main bodys, 121 syringe endoporus, 122 resistance rings

2. push rod: cylindrical shell 212 front end faces 213 endoporus before 21 hollow cylinders 211

Disk 215 rear disks 22 wing plates 23 push pedals before 214

3. piston: 31 cylindrical outer wall, 32 bulge loops, 321 hemispherical projections, 33 nose shape plush coppers

Thin film ring 35 outer film rings 36 front end faces 37 piston inner holes in 34

38 piston rear walls

4. needle stand: 41 puncture needle tubings, 42 binding agents, the 43 preceding faces of cylinder, 44 O-ring cylinders

441 seal grooves, 442 spring-loaded faces, 45 tubular rear portions, 451 localised puncture pawls 452

Positioning table terrace 453 endoporus 454 inner conical surfaces 455 grooves

5.O RunddichtringO:

6. spring

7. plug: 71 mating surfaces, 72 spring-loaded faces

8. needle guard

Five. specific embodiments:

Below in conjunction with legend the present invention is made a kind of embodiment that a detailed description: Fig. 1 is an inner contraction type automatic safety syringe of the present invention (preceding state is used in assembling).Fig. 2 is the enlarged drawing of main functional parts.

As can be seen: puncture needle tubing 41 usefulness bonding agents 42 are connected with needle stand 4, and the positioning table terrace 452 on the needle stand rear elastic localised puncture pawl 451 contacts with the positioning table terrace 113 of syringe 1 preceding cervical region 11 endoporus, and is limited to move backward; Spring 6 skies are enclosed within on the preceding face of cylinder 43 of needle stand, and compressed spring 6 front ends withstand on the endoporus spring-loaded face 72 of plug 7, and the rear end of spring is bearing on the spring-loaded face 442 on the needle stand; Mating surface 71 external diameters of plug 7 are slightly larger than the internal diameter of the preceding mating holes 111 of syringe that cooperates with it, thereby once being pressed into, plug 7 can not withdraw from again.Obviously under the restriction of spring force and syringe locating surface 113, needle stand 4 is limited at shown position and can not moves forward and backward.Because needle stand 4 contacts with syringe 1 step surface 113 with positioning table terrace 452 and supports, thereby needle stand 4 has very high axial stability, can bear bigger spring force and puncture force.

Piston 3 also is assembled to the front end of syringe main body 12 endoporus 121 as seen from Figure 2, the front end face 36 of piston 3 contacts with syringe endoporus 121 bottoms, and to be semicircular bulge loop 32 contact (or close) with the transition circle conical surface 114 on the syringe 1 to cross section, piston 3 front end faces middle part this moment; Nose shape projection 33 on the piston also enters into the endoporus 453 at needle stand 4 tubular rear portions 45, and the pawl point of needle stand 4 localised puncture pawls 451 just in time is in interior thin film ring 34 places of 33 of piston bulge loop 32 and nose type plush coppers; This moment, the front end face 212 of push rod 2 preceding cylindrical shells 211 contacted (or close) with piston bulge loop 32 rear walls.

O RunddichtringO 5 is installed in the seal groove 441 of needle stand 4 O-ring cylinders 44, and the cross section diameter of sealing ring 5 is a bit larger tham the degree of depth of seal groove 441, thereby has guaranteed sealing ring 5 to contact with syringe inner sealing surface 112 and seal groove 441 bottoms and realize sealing function; And owing between sealing ring 5 and the medicinal liquid space one section column sealed district is arranged, the silicone oil of Tian Chonging has completely cut off sealing ring 5 and medicinal liquid therebetween, and sealing ring 5 can not polluted medicinal liquid, has promoted the safety of syringe.

The rear wall 38 of piston 3 is clipped between the preceding disk 214 and rear disk 215 on the push rod front cylinder 211.The cylindrical of preceding disk 214 is identical or smaller with endoporus 37 diameters of piston 3, and its thickness is much smaller than the degree of depth (little 1 ~ 5 millimeter) of piston 3 endoporus 37; And the external diameter of rear disk 215 is slightly less than the diameter of syringe endoporus 121, this design make piston nose face 36 and syringe endoporus bottom contact spacing after, push rod 2 still can be pushed ahead a segment distance, this is an important techniques feature of the present invention.

There is a resistance ring 122 syringe endoporus 121 rear ends, and its internal diameter is less than syringe endoporus 121 diameters.

Push rod tubular endoporus 213 degree of depth are not less than needle stand 4 (together with the injection needle body) length; There are two pairs of mutually perpendicular wing plates 22 cylindrical shell 21 outsides, and the overall dimensions of wing plate 22 is less than resistance ring 122 diameter of bores.

This special construction design of the present invention as can be seen, make piston 3 assemblings the same with ordinary syringe, directly be installed to foremost position, thereby make the convenience of use of this syringe identical with ordinary syringe, the control of injected dose is become easily, and make the power of injecting in the injection process constant all the time, thereby avoided other automatic safety syringes, because of must before the injection terminal point, starting the additional power of injecting that needle retraction device brings, and cause by injector's sense of discomfort.

Syringe of the present invention has very high safety, and as can be seen, really the part that contacts with medicinal liquid only has syringe 1, piston 3 and needle stand 4 from Fig. 1 Fig. 2.This have only three parts to contact with medicinal liquid, reduced the immersion of medicine is polluted, and improved the safety in utilization (4 parts are above to be contacted with medicinal liquid and other similar syringes have at least) of syringe of the present invention.In addition, the structural design of automatic safety syringe of the present invention makes front loaded that needle stand 4, spring 6 can be from syringe cylinder 1, thereby has eliminated the contamination (assembling pollute) of assembly manipulation to syringe main body endoporus 121, has eliminated the indirect pollution to injection.

Fig. 3 is the state that this syringe extracts medicine, as previously mentioned, because assembling back piston 3 front ends do not have the gap, thereby the accurate dosage of easier realization medicine, made things convenient for injection operation.

Fig. 4 is the state that injection finishes, and the present invention's design made before injection finishes as can be seen, did not have the requirement that starts needle retractable mechanism, and the power of injecting of whole injection process is stable substantially, has guaranteed the comfortableness of injection; And can finish in injection, extract syringe needle out after, restart needle retractable mechanism, thereby to being very safe by the injection patient.While is stretched in the endoporus of needle stand 4 rear elastic pawls owing to the nose shape plush copper 33 of piston as can be seen, thereby residual quantity is significantly reduced.

The injecting needle base process analysis figure of retraction is automatically realized in Fig. 5 ~ 6th, safety injector of the present invention.

Fig. 5 is after injection finishes, and promotes to press hands 23 more forward, and push rod 2 continues reach, because the thickness of preceding disk 214 is much smaller than the degree of depth of piston inner hole 37, thereby the rear disk on the push rod 215 will promote piston rear wall 38 and move forward, and piston outer wall 31 will produce compression; And push rod front end face 212 will promote bulge loop 32 reaches of piston nose, because the inside and outside bonding pad 34,35 of bulge loop is thin film, thereby can not produce obvious inhibition.Bulge loop 32 is when moving forward, be subjected to the guide function of the transition conical surface 114 on the syringe and move to the center, thereby the elasticity localised puncture pawl 451 at compressing needle stand rear portion inwardly shrinks, because piston prenasal shape plush copper 33 diameters are less than needle stand rear portion endoporus 453 diameters, thus can not limit elastic claw 451 in contract.When being reduced to positioning table terrace 452 on it in the elasticity localised puncture pawl 451 and breaking away from the anterior positioning step 113 of syringes, needle stand 4 promptly is disengaged constraint, moves to the syringe rear portion under spring 6 effects.

Because the positioning table terrace 452 during assembling on the needle stand 4 is bearing on the anterior positioning step 113 of syringe, thereby stronger spring 6 is adopted in permission, make the rupture strength of its spring force greater than piston thin film 34, then the needle stand 4 of constraint relief is under the effect of spring 6, move to piston 3 directions, sharp-pointed pawl point on the needle stand rear portion localised puncture pawl 451 will puncture, and tear the interior thin film ring 34 on the piston 3; (the nose type plush copper 33 on the piston has also limited the deflection of interior thin film ring 34, makes it be easier to be punctured, and tears) also makes piston antetheca middle part (comprise nose shape 33) separate (Fig. 6) with piston 3.Loosen push rod 2, under the elastic reaction of piston 3, push rod 2 retreats and resets, this moment, bulge loop 32 also resetted, then needle stand 4 promptly can be freely entering into push rod endoporus 213 with a piston nose shape under being cut 33 under the effect of spring force together, thereby realized the security protection of syringe needle, as shown in Figure 7.

In order to reduce the thrust that makes 32 reaches of piston nose face bulge loop, the bulge loop 32 at described piston (3) front end face middle part also can change by the hemispherical projections (321) by annular spread more than 3 to be formed, as shown in figure 10.

The drift of spring 6 is greater than needle tubing 41 length, thereby after in case needle stand 4 is pushed into push rod endoporus 213, syringe needle just can not stretch out outside the syringe 1 again, as shown in Figure 7: in addition since push rod on rear disk 215 diameters greater than syringe endoporus rear portion resistance ring 122 internal diameters, and rear disk 215 rear ends are verticals, therefore in a single day push rod 2 packs into, and (rear disk 215 front end faces are arc surfaces in syringe 1 back, thereby be easy to pack into), then be difficult to from syringe, pull out again (particularly a little less than push rod rear portion wing plate 22 is made book, distinguishing), prevented that syringe needle is free outside syringe, and damaged or utilized once more.

From above-mentioned analysis as can be seen, inner contraction type automatic safety syringe of the present invention has following advantage

1. have very high safety:

1.1 the pollution to medicinal liquid is little:

1.1.1 syringe of the present invention only has three parts: syringe, piston, needle stand contact with medicinal liquid, thereby reduce

To " the quiet pollution " of medicine;

1.1.2 install, thereby " the assembling pollution " to the syringe inwall having avoided many similar syringes in syringe, to install bringing because needle stand and spring can adopt from syringe is anterior.

1.1.3 the mutual extrusion, the friction that start between the necessary correlated parts of release mechanism all can be carried out after injection, thereby " the moving pollution " of the injection that does not cause thus.

1.2 reliable, lasting to the security protection of syringe needle: because the automatic retraction of needle point is easily realized in the injection back, avoid the contaminated needle point of issuable operator to draw, stab danger and make in the whole last handling process fully, needle point all is in effective guard mode.

2. easy and simple to handle, little to patient's influence: the design of the zero clearance of piston assembling, make injector to inject operation and ordinary syringe basic identical, be easy to realize accurate dosage, the easier operator of being accepts.While is because in whole injection process, no additional forces (and general automatic safety syringe requires to start safety device before the injection terminal point) thereby injection process are steady, and reason is not injected the variation of power and made the patient produce incompatibility sense or pain.

3. needle stand of the present invention is realized the location with structure stress, thereby stability is high, and anti-puncture force is strong.Because adopt the lever principle release, tripping force is little, so safety injector of the present invention has and manipulates characteristic preferably.

4. use the back piston destroyed and rear disk 215 diameters on the push rod greater than syringe resistance ring 122 internal diameters, make the syringe needle that has bounced back can not extract reuse once more out, prevent the repeated use of syringe effectively.

5. the needle stand of syringe is to realize the location with structure stress, and seal request is to realize by rubber seal, thereby has reduced the part precision requirement, promptly has anufacturability preferably.

6. this syringe part less (comprising that needle guard 8 has eight parts), part processing precision is not high relatively, assembles easyly, be suitable for (automatization) in enormous quantities and produce, thereby cost is lower, and very high cost performance is arranged.

Fig. 8 is an another embodiment of the present invention: its main feature is with plug 7 cancellations, and O RunddichtringO 5 is moved on in the front sealing annular groove 115.This kind structure is not only saved a plug part, simplify the structure, and O RunddichtringO change in size is smaller to the influence of retraction; Because the sealing effect that the silicone oil that utilizes the very little fit clearance between needle stand O-ring cylinder 44 and the syringe sealing surface 112 simultaneously and exist therebetween forms is realized the prime sealing, block injection and entered the front springs space, thereby can not cause residual quantity to increase problem.This design has kept the major advantage of above-mentioned embodiment fully: the part number that contacts with medicinal liquid is few, and needle stand and spring are packed into from the front portion, brings assembling to pollute can for the syringe inwall, and the safety of syringe is very high; And the O RunddichtringO does not enter in the hollow hole of push rod with needle stand, has reduced the required precision to O RunddichtringO size relatively, and cancellation plug part, thereby makes production cost be able to further reduction, thereby this scheme has more practical value.

Fig. 9 is another structural design of this syringe, and the less front step hole (116) of the preceding cervical region of syringe (1) (11) cooperates with the preceding face of cylinder of needle stand (43), and bigger backward step hole (117) cooperates with needle stand O-ring cylinder (44); Spring (6) is installed between step surface (118) and the needle stand spring-loaded face (442).This organization plan only has 5 (not comprising pin medicated cap 8) parts, it is the simple structure of similar automatic safety syringe, realize sealing by the silicone oil in the less fit clearance between above-mentioned seal section, this scheme production cost is minimum, but its safety and reliability are all not as good as aforementioned two schemes, as a kind of automatic safety syringe cheaply, has certain use value.

Claims (7)

1. an inner contraction type automatic safety syringe comprises syringe (1), the push rod (2) of being with center cavity, piston (3), the needle stand (4) of being with injection needle, o RunddichtringO (5), reaches spring (6), it is characterized in that:

The one transition conical surface (114) is arranged between the endoporus (121) of the endoporus of the preceding cervical region of described syringe (1) (11) and syringe main body (21), be provided with the positioning table terrace (113) that a diameter is a bit larger tham the transition conical surface (114) small end bore dia at the transition conical surface (114) front end, O-ring cylinder (112) is established at the endoporus of cervical region (11) middle part before the syringe, and its diameter is less than the described transition conical surface (114) small end bore dia;

It is semicircular bulge loop (32) that there is a cross section at piston (3) front end face middle part, its centrage is at the aforementioned transition circle conical surface (114) medium position, described semicircle bulge loop (32) is connected with piston (3) front end face middle part by an annular membrane (34), and semicircle bulge loop (32) is connected with the cylindrical outer wall (31) of piston (3) by another annular membrane (35);

Needle stand (4) is made up of nose circle cylinder (43) and tubular rear portion (45), described nose circle cylinder (43) is formed by being the step-like continuous face of cylinder more than two, wherein the step between the face of cylinder (44), back and the preceding face of cylinder is spring-loaded face (442), on the face of cylinder, back (44), be provided with seal groove (441), o RunddichtringO (5) is housed in seal groove (441); One step locating surface (452) is arranged on the described tubular rear portion (45), can overlap with the positioning table terrace (113) on the cervical region before the aforementioned syringe, endoporus (453) rearward end at described needle stand tubular rear portion (45) is an internal taper hole (454); Establish plural groove (456) on the whole tubular rear portion (45), make tubular rear portion (45) be divided into several localised puncture pawls (451);

The center of described push rod (2) is a hollow cylinder (21), its internal diameter is slightly larger than the external diameter of aforementioned needle stand (4), front cylinder (211) external diameter on the hollow cylinder (21) is less than the above-mentioned syringe transition conical surface (114) outside diameter, and contacts with the inwall of the semicircle bulge loop (32) of above-mentioned piston (3).

2. a kind of automatic safety syringe according to claim 1 is characterized in that: the groove (456) on the described tubular rear portion (45) is a direct through groove.

3, a kind of automatic safety syringe according to claim 1 is characterized in that: the oblique groove of the groove (456) on the described tubular rear portion (45) for being shunk by the rear end forward end.

4. a kind of automatic safety syringe according to claim 1, it is characterized in that: disk (214) before the preceding cylindrical shell of described push rod (2) (211) cylindrical is provided with, its diameter is slightly less than piston (3) endoporus (37) diameter, and its thickness is less than 1～5 millimeter of piston inner hole (37) degree of depth.

5. a kind of automatic safety syringe according to claim 1, it is characterized in that: there is a nose projection (33) described piston (3) front portion, its external diameter is less than aforementioned needle stand (4) tubular rear portion (45) endoporus (453) diameter, and its length is less than needle stand tubular rear portion endoporus (453) degree of depth; Link to each other by described annular membrane (34) between nose projection (33) root and the described semicircle ring-type projection (32).

6. according to the arbitrary described a kind of automatic safety syringe of claim 1 to 5, it is characterized in that: the preceding cervical region of described syringe (1) is equipped with a plug (7), one spring-loaded face (72) is arranged in the endoporus of plug (7), preceding mating holes (111) close-fitting of the mating surface (71) of plug (7) and the preceding cervical region of described syringe (1) (11) is between the spring-loaded face (442) of described spring (6) compression ground installing aforementioned spring-loaded face (72) and needle stand (4) front end.

7. according to the arbitrary described a kind of automatic safety syringe of claim 1 to 5, it is characterized in that: be provided with a closure gasket groove (115) in the preceding cervical region of described syringe (1) (11), described o RunddichtringO (5) is installed in the sealing annular groove (115), and closely contacts with needle stand (4) nose circle cylinder (43) surface; Spring (6) is installed between the spring-loaded face (442) on o RunddichtringO (5) and the needle stand (4).

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