CN103599582A - Aerodynamic safety syringe - Google Patents

Abstract

An aerodynamic safety syringe comprises a jacket, a needle, a needle seat, a piston, a push rod, and an outer tube. The front section of the needle seat penetrates the opening of a conical hole of the outer tube. The end face of the middle section of the needle seat is in seal contact with the inner inclined face of the conical hole. The outer peripheral disc of the rear section of the needle seat is mounted in the inner cavity of the front section of the jacket to form mutual seal. The piston is in slide seal with the inner wall of each section of the outer tube. A suspending body in a piston inner hole is embedded into a constricted hole of the upper section of the push rod. After injection, a user continues to press the push rod, the salient point at the front end of the push rod presses the disc from one side to allow the same to be separated from the rear section of the needle seat, the needle seat presses the annular channel in the middle of the piston to allow the suspending body to move downwards along the constricted hole of the push rod and to be separated from the piston, a retraction passage is opened when the suspending body completely enters the inner cavity of the push rod, the compressed air in the front section of the outer tube injects the needle seat, the needle and the suspending body into the inner cavity of the push rod, and in the mean time, the inner hole of the suspending body is allowed to be in embedment with a conical column at the bottom of the push rod so as to allow the needle to be shielded from being exposed. The aerodynamic safety syringe is simple in structure, easy to manufacture, practical, safe and reliable.

Description

Aerodynamic type safety injector

(1), technical field

The present invention relates to a kind of medical apparatus and instruments, specifically for to the piercing process of tissue and after puncture to organizing inner injecting and administering or extracting the aerodynamic type safety injector of tissue specimen.

(2), background technology

Chinese Patent Application No. 201120442311.1 has been announced vapour-pressure type retraction self-destroyed syringe, comprise injection tube, the hollow injection rod of tubular, needle stand, sealing gasket, piston and seal nipple, the central authorities of needle stand are provided with syringe needle, needle stand is arranged on the front end of injection tube by being sleeved on the sealing gasket of its lower end, piston bush is located at the outside of injection rod front end, seal nipple is arranged on the interior survey of injection rod front end, seal nipple and needle stand are provided with the syndeton of working in coordination, it is characterized in that: when described injection rod is pushed into the front end of described injection tube, the outer wall hermetic seal of the inwall of injection tube front end and needle stand front end, on injection rod inwall, be provided with the stopping means that stops seal nipple and needle stand to penetrate from injection rod lower end, injection rod lower end is provided with links up injection rod inner chamber and extraneous steam vent.The bottom outwardly convex of described needle stand forms limit base, and sealing gasket is sleeved on limit base and makes needle stand outer wall and the hermetic seal of injection tube inwall; Described stopping means has two, is separately positioned on injection rod middle part and bottom, and stopping means is exactly injection rod inwall Shang tri-road convex tendons.

Though this technical scheme and application number 201310057218.6 mechanical force (spring force or artificial pulling force) of utilizing more in the past has compared with much progress self-destruction or the safety injector of needle stand and needle tubing retraction, its principle is to continue reach at push rod, and crush seal circle is to overcoat ante-chamber air compressing; Until push rod is while being expressed to the stage casing of needle stand by sealing ring, air compressing is to minimum volume (pressure is maximum), and sealing ring loses the package action of needle stand, discharges needle stand, and under compressed air effect, needle stand launches to push rod inner chamber rapidly; 1., in this scheme but have the following disadvantages:, what needle stand lower lobes formed is limit base, is only to coordinate with sealing gasket, completes the hermetic seal between needle stand and injection tube inwall, spacing needle stand, make its can not after move.In literary composition, there is no explanation: limit base will have certain length, make sealing gasket under the surface of limit base can the extruding at injection rod, during slipper seal, reach certain distance, complete the seal compression to injection tube front end inner chamber air, produce and make needle stand and seal nipple launch needed certain pressure intensity (kinetic energy) to push rod inner chamber.So, the description of technique scheme, only that sealing gasket is advanced to needle stand middle part from limit base, this distance is difficult to realize needed pressure to the compression of injection tube front end inner chamber air, especially the syringe of small dimension (being less than 1.0ml), its injection tube intracavity diameter is less than 4.0mm, and general sealing gasket thickness is 2-3.0mm approximately; Compression distance so, atmospheric pressure is extremely faint, is the needs that can not realize needle stand retraction described in such scheme; 2., because this scheme has been utilized needle stand lower end endoporus and the interconnective structure of seal nipple front end plug, side makes the two drive needle tubing to bounce back together and enters injection rod inner chamber; Due to the connection space existing between needle stand endoporus and seal nipple, drug residue is increased, especially valuable drug, can cause drug waste and curative effect to reduce; This point is also that this scheme causes under triggering state, the reason that medicinal liquid sprays to taper hole the place ahead; 3., because this scheme is to utilize the interaction at middle part and San road, bottom convex tendon in the bottom margin of seal nipple and injection rod, realize spacing to syringe needle, it can not be penetrated from injection rod lower end, can not in injection rod upper end hole, expose simultaneously.Because this scheme exists the above-mentioned the deficiency or defect 2., make its retraction uncertain, especially during small dimension injection tube, retraction not just; So syringe needle, needle stand and seal nipple together bounce back (ejaculation) may: not exclusively enter injection rod inner chamber, be that syringe needle and needle stand and seal nipple fail to be penetrated, retract between two stopping means by enough compressed airs, so, needle point just can not enter injection rod inner chamber completely, and continue to expose, there is the risk of needle stick injury.

(3), summary of the invention

In order to overcome the deficiency of such scheme, the object of the present invention is to provide after improvement, structure is more succinct, cost is lower, safe and reliable, practicality is good, can realize automatization produces in enormous quantities, and be the Novel safety syringe of numerous medical personnel's acceptance.

To achieve these goals, technical scheme of the present invention is such: aerodynamic type safety injector, consists of jointly push rod, piston, needle stand, needle tubing, urceolus, sheath; It is characterized in that: needle stand is arranged in urceolus leading portion inner chamber, needle stand leading portion is through urceolus taper hole, and the taper hole of the outer cylinder front end inclined-plane forming that slopes inwardly contacts sealing with the formation of needle stand stage casing end face; In the outside of needle stand back segment, there is a disk, be together arranged in the front end inner chamber of urceolus with needle stand, make to form gas-liquid sealing between needle stand and urceolus, also make the space of urceolus leading portion seal completely; Piston is cap-like structure, and its upper end face has a bullet, and the outer rim up and down of piston has two annular protrusions, and piston is arranged on the front end outside of push rod, and push rod and piston are arranged on outer tube inner chamber, and between each section of inwall of piston and urceolus, being slides closely cooperates.

Piston is made by elastomeric material, and the upper end face of piston has its side of a cone to have a plurality of longitudinal grooves, and it is chimeric that its form can be mated with needle stand back segment endoporus formation; The appearance side of piston respectively has an annular projection up and down, and its slightly larger in diameter is in the internal diameter of each section of urceolus; There is blind hole the lower end of piston, and internal diameter mates with drawbar epimere profile, can form chimeric; At the basilar part of piston inner hole, have the body that dangles, its slightly larger in diameter is in the diameter in push rod front end constriction hole, but is less than the internal diameter of tube chamber in push rod, and the height of the body that dangles equals the degree of depth of push rod epimere constriction endoporus; Piston upper end face corresponding with the body that dangles, has a ring-shaped groove, and its diameter equals the diameter of needle stand back segment.

The epimere external diameter of needle stand is slightly less than the diameter at outer cylinder front end conehead bore openings place; Needle stand stage casing external diameter is greater than outer cylinder front end taper hole opening part diameter inner edge but is less than urceolus taper hole internal diameter; The stage casing end face of needle stand is smooth smooth, and the back segment diameter of needle stand is greater than needle stand stage casing diameter, in the outer rim of needle stand back segment, has a disk, and its slightly larger in diameter is in the internal diameter of urceolus leading portion; The disk junction of needle stand back segment and outer rim is poor, and needle stand has through hole, the tapered expansion in hole of needle stand back segment bottom, and its internal diameter mates with the bullet of piston upper end face.

There is hollow luminal structure described push rod one end, and its epimere endoporus perisporium is constriction hole ringwise, and the degree of depth in constriction hole equals the dangle height H of body of piston; The diameter in constriction hole is less than the maximum outside diameter D of the body that dangles; There are two annular protrusions in the outside of push rod upper end, can be closely chimeric with piston inner hole, and in push rod, the diameter of tube chamber is greater than the maximum outside diameter of the body that dangles; The degree of depth of push rod inner chamber is greater than the summation of needle stand and needle tubing and the body length that dangles; The expansion of push rod lower end is tabular, the basilar part of tube chamber in push rod, there is a conoid pole, its periphery has several apertures and push rod endoporus to connect, front end end face at push rod has a salient point, in the lower end of push rod, have an annular flake, its diameter equals urceolus internal diameter, but is slightly larger than the diameter of urceolus back segment inner chamber annular projection.

Described urceolus is hollow structure, and its front end has the conehead dwindling, and there is taper hole in its central authorities, and the opening part of taper hole dwindles, and the inner edge of taper hole opening part is formed slopely annular slope to taper hole inwall, and its inclination angle is between 1～60 °; The internal diameter of urceolus leading portion is slightly less than the internal diameter of urceolus posterior segment, and the length of urceolus leading portion equals or be slightly larger than the summation of disk thickness with the height H that dangles of needle stand back segment; There is an annular protrusion urceolus leading portion and junction, stage casing, and its diameter is slightly less than urceolus leading portion internal diameter; The back segment inwall of urceolus has an annular protrusion, and its internal diameter is less than the diameter of push rod back segment ring segment.

Needle stand is arranged in the front end inner chamber of urceolus, forms sealing and build-in between needle stand disk and urceolus epimere inwall, and this build-in force is greater than 10N, to meet the non-return power requirement to entry needle.

The present invention has following technical characterictic and technological progress:

Because the present invention has adopted after liquid medicine injection, continue pressure-ram, make the section surface reach after needle stand of piston outside, compression urceolus leading portion inner chamber air, simultaneously, the bump structure of push rod front end one side, can be by the disk of needle stand back segment, run-off the straight, fracture; At the whole latter end of compression, make needle stand disk be advanced to needle stand stage casing, discharge needle stand; Simultaneously, under the extruding of needle stand back segment, the body that dangles in piston inner hole moves to push rod inner chamber, along with piston further the moving down of body of dangling, the ring-shaped groove of the junction between body and piston body of dangling is mutually squeezed and cuts by needle stand back segment bottom surface and push rod epimere end face, rupture, finally fracture completely.The restriction that continue compressing push rod, the body that makes to dangle departs from push rod endoporus epimere narrowed portion gradually, in free state, under compressed-air actuated effect, dangle body together with needle stand and needle tubing by directive push rod inner chamber rapidly; Make the technical program utilize spring and the scheme such as manually pull back, there is feature simple in structure, with low cost, easy to manufacture.

The structure that adopts needle stand bottom endoporus to dangle body, utilize its cone mutually to mate with piston due to the present invention; Can make in the process of pressure-ram, make the body that dangles of piston be oppressed chimeric and increase along with moving into the degree of depth of push rod inner chamber by needle stand, the body that makes to dangle is separated with piston generation fracture, and last, the body that dangles enters push rod endoporus completely, opened push rod bore passages; Adopted the structure that conoid pole is set and is fitted with the body lower end endoporus that dangles at push rod intracavity bottom simultaneously, make after triggering release compressed air, needle stand is dangled, and body is chimeric to be pind down, the body that dangles is pind down by the conoid pole of push rod intracavity bottom is chimeric again, thereby needle stand is fixed in push rod inner chamber, can not again exposes.Make the present invention there is retraction reliable, definite, the simple in structure feature of shielding needle tubing.

The technical program is easy to manufacture, safe and reliable, implement simply, widely applicable, is beneficial to universal.After use, can realize that device pin unmakes, needle point shielding, eliminate needle stick injury, avoid medical personnel and other staff are infected and spread disease by pricking wound.

(4), accompanying drawing explanation

Fig. 1 is that the integral body of aerodynamic type safety injector of the present invention forms decomposing schematic representation;

Fig. 2 is the half sectional view of the piston structure of aerodynamic type safety injector of the present invention;

Fig. 3 is the half sectional view of the pusher structure of aerodynamic type safety injector of the present invention;

Fig. 4 is the half sectional view of the outer tube structure of aerodynamic type safety injector of the present invention;

Fig. 5 is the cutaway view of the needle stand structure of aerodynamic type safety injector of the present invention;

Fig. 6 is that urceolus and the needle stand of aerodynamic type safety injector of the present invention installed positionality schematic diagram;

Fig. 7 is the mutual locations of structures graph of a relation of aerodynamic type safety injector piston of the present invention and push rod;

Fig. 8 is the complete structure schematic diagram of aerodynamic type safety injector of the present invention;

Fig. 9 to be aerodynamic type safety injector of the present invention break in push rod reach, by the disk extruding of needle stand bottom needle stand is discharged after, piston compression air is needle stand, needle tubing and the body directive push rod inner chamber that dangles, dangle body and push rod intracavity bottom conoid pole is chimeric, and needle stand, needle tubing are formed restriction, make its shielding at the structural representation of push rod inner chamber.

(5), specific embodiment

As shown in Figure 1, aerodynamic type safety injector of the present invention by: push rod 1, piston 2, needle stand 3, needle tubing 4, urceolus 5, sheath 6 form jointly.8 is known by reference to the accompanying drawings: sheath 6 can be enclosed within the conehead appearance of urceolus 5 front ends, to protect the cutting edge of needle tubing, is not damaged; Needle tubing 4 is tubular structures that stainless steel material is made, and there is sharp cutting edge 41 one end; Needle stand 3 is cylindrical tube structures, and there is through hole in central authorities, and there is the disk 34 of an expansion needle stand one end, piston 2 be plastic material make there is certain elastic cap-like structure; Push rod 1 is that one end is hollow pipe column structure; Urceolus 5 is hollow tubular, and they are sequentially assembled into the present invention.

Referring to Fig. 2, piston 2 be plastic material make there is certain elastic cap-like structure, its upper end face has a bullet 23, in the side of bullet, has a longitudinal groove 24 at least; The outer rim up and down of piston respectively has an annular projection 22, and this protrusion diameter is slightly larger than urceolus 5 each section of internal diameter, forms slipper seals with urceolus 5 inwalls; At the upper end face of piston 2, the base peripheral of bullet 23, have a ring-shaped groove 27, its diameter to equal needle stand 3 hypomere 33 external diameters; There is a downward blind hole 26 in central authorities at piston 2, and mate with two annular projections of push rod 1 upper end in its upper-lower section aperture, forms chimeric; Basilar part in piston 2 blind holes 26 has a circle to dangle body 25, its slightly larger in diameter in the constriction hole of push rod 1 leading portion 12 internal diameters, but is less than the internal diameter of push rod tube chamber 11, and the height H of the body 25 that dangles equals the degree of depth in push rod epimere constriction hole 12; The length that the height H of body 25 of dangling is slightly less than urceolus leading portion 53 deducts the thickness of needle stand root disk 24; Periphery is corresponding with it at the upper surface of the body 25 that dangles for ring-shaped groove 27, makes this place piston cross-section, to be piston 2 be narrow with ring-shaped groove 27 between body 25 and be connected with dangling, and it externally easily ruptures under shear action.

As shown in Figure 3, there is the tube chamber 11 of hollow one end of push rod 1, and its upper end appearance has two annular protrusions,, can with piston 2 endoporus 26 match chimeric (in conjunction with Fig. 2, Fig. 7); The inside constriction 12 of leading portion endoporus of push rod 1 tube chamber 11, its diameter is slightly less than the maximum outside diameter D (in conjunction with Fig. 2) of the body 25 that dangles at piston 2 endoporus 26 middle parts; The internal diameter of push rod tube chamber 11 is greater than the external diameter of dangle body 25 and needle stand back segment 33.The degree of depth of push rod tube chamber 11 is greater than the summation of needle stand 3 and needle tubing 4 length and body 25 length of dangling; One conoid pole 14 is arranged at the bottom of push rod tube chamber 11, and its diameter is mated (referring to Fig. 2) with the body 25 bottom endoporus 28 that dangle; Surrounding at conoid pole 14 has several apertures 15 and push rod tube chamber 11 to connect, and push rod hypomere has the disk 16 of expansion, its diameter to equal urceolus internal diameter, but is slightly less than the diameter (in conjunction with Fig. 4) of urceolus hypomere constriction ring 54; Push rod lower end expands 17 in the form of sheets, becomes and injects handle.

Fig. 4 is the half sectional view of the outer tube structure of aerodynamic type safety injector of the present invention; As seen from the figure, urceolus 5 is hollow structure, and its front end has a conehead, at the front end of conehead, has taper hole, connects with urceolus 5 inner chambers, and taper hole opening part is narrow 51, the inwall of stenosis is formed slopely inclined-plane 52 to cone-shaped wall, and its angle can be between 1～60 °; The internal diameter of the leading portion 53 of urceolus is slightly less than the internal diameter of urceolus 5 stage casings and back segment, and there is a constriction ring 53A urceolus leading portion and junction, stage casing, and its internal diameter is less than the external diameter (in conjunction with Fig. 5) of needle stand 3 hypomere disks 34, is also less than urceolus leading portion 53 internal diameters; This constriction ring 53A equals the summation of needle stand stage casing 32 and needle stand back segment 33 length to the length on the interior inclined-plane 52 of urceolus taper hole 51; The length of urceolus leading portion 53 is greater than needle stand back segment disk 34 thickness and the summation (in conjunction with Fig. 2, Fig. 5) of body 25 height H of dangling.In urceolus 5, the internal diameter of back segment inner chamber is slightly less than the external diameter of piston 2; Inwall at overcoat back segment has a constriction ring 54, and its diameter is slightly less than the diameter of the disk 16 of push rod hypomere expansion; The curling operating grip 55 that becomes of back segment outer wall expansion of urceolus 5.

Fig. 5 is the cutaway view of the needle stand structure of aerodynamic type safety injector of the present invention; Referring to Fig. 7, Fig. 8 and Fig. 9, known, needle stand 3 is round tube shape structures, and there is through hole 31 in central authorities, and the leading portion external diameter of needle stand 3 is slightly less than urceolus 5 front end taper hole opening part 51 internal diameters; The stage casing external diameter of needle stand 3 is greater than the external diameter of needle stand leading portion, the end face in needle stand stage casing, and 32 is smooth smooth; Back segment 33 external diameters of needle stand 3 are greater than the external diameter in needle stand stage casing; In needle stand back segment outer rim, have a disk 34, its cross section is curved, and its external diameter is slightly larger than urceolus leading portion 53 internal diameters, and the junction 34A of itself and needle stand back segment 33 is poor; Needle stand back segment endoporus 35 is a taper, and its internal diameter mates with the taper thorn 23 of piston 2 front ends.

Fig. 8 is the complete structure schematic diagram of aerodynamic type safety injector of the present invention; Simultaneously referring to Fig. 5, Fig. 6, Fig. 7 and Fig. 8; Needle tubing 4 is bonded in the front end endoporus 31 of needle stand 3, and the leading portion of needle stand 3 is through the conehead bore openings place 51 of urceolus, and between the lean-in inclined-plane 52 of needle stand stage casing end face 32 and urceolus conehead endoporus 51, formation contacts sealing, (seeing Fig. 6, Fig. 8); Needle stand 3 is arranged in urceolus 5 leading portion inner chambers 53, and is positioned at the top of the junction annular protrusion 53A in urceolus leading portion and stage casing, make needle stand 3 with in the disk 34 of its outer rim and urceolus 5, back segment forms gas-liquid sealing; Equally, urceolus 5 leading portion 53 inner chambers, the space that the stage casing end face 32 of outer cylinder front end inwall and needle stand 3 forms is in complete sealing state (seeing Fig. 6); Piston 2 is sleeved on the front end appearance of push rod 1, and the body 25 that dangles in piston inner hole 26 embeds in push rod 1 leading portion constriction endoporus 12 and closely cooperates and form slipper seal (seeing Fig. 7), and then push rod and piston are installed in urceolus 5 inner chambers (seeing Fig. 8); The length of urceolus leading portion 53 is slightly larger than disk 34 thickness of needle stand back segment 33 outer rims and the summation of body 25 height H of dangling.

In use, conventional according to injection, after local tissue disinfection, extract medicinal liquid, after deaeration, in accordance with doctor's advice, in local organization, puncture, mutual pressure-ram and urceolus handle, liquid medicine injection, along with the reach of push rod, the bullet 23 of piston upper end enters in needle stand 3 hypomere endoporus, medicinal liquid enters needle stand 3 endoporus 31 through bullet side groove 24 and enters human body through entry needles, until, needle stand back segment 33 and piston 2 upper end bullets 23 interact chimericly, injecting liquid drug is complete, by the sealing of needle stand endoporus, needle tubing inner liquid medicine can not be outflowed.

Referring to Fig. 8 and Fig. 9, when aerodynamic type safety injector of the present invention is after injection predetermined close medicinal liquid, from tissue, pull out puncture needle, observe puncture needle integrity degree (guarding against puncture needle phenomenon of rupture), with the definite action of unmaking, pressure-ram 1 firmly, the salient point 13 of push rod front end one side can tilt pushing before disk 34 1 side direction of needle stand 3 bottoms, making it, make the junction of itself and needle stand back segment 33 that local fracture occur, then fracture comprehensively, disk 34 and needle stand bottom 33 are departed from completely, needle stand 3 is discharged; Pressure-ram 1 further moves forward it, drives the air in piston 2 compression urceolus ante-chambers 53; Simultaneously, needle stand 3 back segment 33 bottom periphery compressings are at the inner edge of piston face ring-shaped groove 27, the body 25 that dangles of its below is moved down along push rod endoporus 12, when piston extruding urceolus ante-chamber at least 80% air volume, dangle body 25 and piston 2 at ring-shaped groove 27 places, there is fracture completely and depart from (ring-shaped groove is squeezed by push rod upper end outer rim and needle stand bottom outer rim the effect of cutting mutually), but, because the external diameter of cylinder 25 is greater than the diameter of push rod upper end endoporus, can effectively seal to the upper end of push rod endoporus the compression of this process implementation to overcoat leading portion air; Along with the thorough reach of push rod, piston is thoroughly expressed to needle stand disk 24 front end of urceolus.Air is thoroughly compressed.The dangle body 25 separated with piston thoroughly pushed and moves down by needle stand 3 hypomeres 33, enter tube chamber 11 in push rod, this place's diameter of bore is greater than the external diameter of the body 25 that dangles, the body 25 that makes to dangle thoroughly departs from the constraint of push rod endoporus upper end, enter push rod inner chamber 11 completely, piston 2 and needle stand stage casing end face 32 have been broken and the sealed environment of dangle body 25 and 12 formation of push rod front end constriction hole, open channel is only push rod front end endoporus 12, now, because needle stand 3 has lost the fixing and constraint of disk 34 to it, under the compressed-air actuated effect of urceolus 5 leading portion inner chamber 53, needle stand 3, needle tubing 4 discharges rapidly, with the together depths of compressed air directive push rod 1 inner chamber 11 of body 25 of dangling, in push rod, a plurality of apertures 15 of tube chamber 11 bottoms can be drained compressed air, eliminate counteracting force, now, because the bottom endoporus 28 of the body 25 that dangles is chimeric with conoid pole 14 formation of push rod bottom, can pin down needle tubing 4 can not expose, needle tubing 4 is shielded in push rod inner chamber 11, prevent the pollution of environment and eliminated the risk of medical personnel's needle stick injury.

Technical scheme described in the invention, any similar distortion that can realize by distortion at those skilled in the art, all will fall into technology category of the present invention.

Claims (5)

1. aerodynamic type safety injector, consists of jointly push rod (1), piston (2), needle stand (3), needle tubing (4), urceolus (5), sheath (6); It is characterized in that: needle stand (3) is arranged in urceolus leading portion inner chamber (53), needle stand leading portion is through urceolus taper hole (51), and the taper hole (51) of urceolus (5) the front end inclined-plane (52) forming that slopes inwardly contacts sealing with needle stand stage casing end face (32) formation; In the outside of needle stand (3) back segment (33), there is a disk (34), together be arranged in the front end inner chamber (53) of urceolus (5) with needle stand (3), make to form gas-liquid sealing between needle stand (3) and urceolus (5), also make the space of urceolus leading portion (53) seal completely; Piston (2) is cap-like structure, its upper end face has a bullet (23), the outer rim up and down of piston has two annular protrusions (22), piston (2) is arranged on the front end outside of push rod (1), push rod (1) and piston (2) are arranged on urceolus (5) inner chamber, and between piston (2) and each section of inwall of urceolus (5), being slides closely cooperates.

2. aerodynamic type safety injector according to claim 1, it is characterized in that: piston (2) is made by elastomeric material, the upper end face of piston has a cone (23), there are a plurality of longitudinal grooves (24) its side, and it is chimeric that its form can be mated with needle stand back segment endoporus (35) formation; The appearance side of piston respectively has an annular projection (22) up and down, and its slightly larger in diameter is in the internal diameter of each section of urceolus (5); There is blind hole (26) lower end of piston, and internal diameter mates with drawbar (1) epimere profile, can form chimeric; At the basilar part of piston inner hole (26), there is the body (25) that dangles, its diameter D is slightly larger than the diameter in push rod front end constriction hole (12), but the internal diameter that is less than tube chamber (11) in push rod, the height H of the body that dangles (25) equals the degree of depth of push rod epimere constriction endoporus (12); (25 corresponding piston upper end faces, have a ring-shaped groove (27), and its diameter equals the diameter of needle stand (3) back segment (33) with the body that dangles.

3. aerodynamic type safety injector according to claim 1, is characterized in that: the epimere external diameter of needle stand (3) is slightly less than the diameter at outer cylinder front end conehead bore openings place (51); Needle stand stage casing external diameter is greater than outer cylinder front end taper hole opening part (51) diameter inner edge but is less than urceolus taper hole internal diameter; The stage casing end face of needle stand (3) is smooth smooth, back segment (33) diameter of needle stand (3) is greater than needle stand stage casing diameter, outer rim at needle stand back segment (33) has a disk (34), and its diameter B is slightly larger than the internal diameter of urceolus leading portion (53); Needle stand back segment (33) is poor with the disk junction (34A) of its outer rim, needle stand (3) has through hole (31), the tapered expansion in hole (35) of needle stand back segment (33) bottom, its internal diameter mates with the bullet (23) of piston (2) upper end face.

4. aerodynamic type safety injector according to claim 1, it is characterized in that: there is hollow tube chamber (11) structure described push rod (1) one end, its epimere endoporus perisporium is constriction hole (12) ringwise, and the degree of depth of constriction hole (12) equals the dangle height H of body (25) of piston (2); The diameter in constriction hole (12) is less than the maximum outside diameter D of the body that dangles (25); There are two annular protrusions in the outside of push rod upper end, can be closely chimeric with piston (2) endoporus (26), and the diameter of the interior tube chamber of push rod (1) (11) is greater than the maximum outside diameter of the body that dangles (25); The degree of depth of push rod (1) inner chamber (11) is greater than the summation of needle stand (3) and needle tubing (4) and the body that dangles (25) length; The expansion of push rod lower end is tabular (17), the basilar part of tube chamber in push rod (11), there is a conoid pole (14), its periphery has several apertures (15) and push rod endoporus (11) to connect, front end end face at push rod (1) has a salient point (13), in the lower end of push rod, have an annular flake (16), its diameter equals urceolus (5) internal diameter, but is slightly larger than the diameter of urceolus back segment inner chamber annular projection (54).

5. aerodynamic type safety injector according to claim 1, it is characterized in that: described urceolus (5) is hollow structure, its front end has the conehead dwindling, there is taper hole in its central authorities, the opening part of taper hole dwindles (51), the inner edge of taper hole opening part is formed slopely annular slope (52) to taper hole inwall, and its inclination angle is between 1～60 °; The internal diameter of urceolus leading portion (53) is slightly less than the internal diameter of urceolus posterior segment, and the length of urceolus leading portion (53) equals or be slightly larger than disk (34) thickness of needle stand back segment (33) and the summation of body (25) height H of dangling; There is an annular protrusion (53A) urceolus leading portion and junction, stage casing, and its diameter is slightly less than urceolus leading portion (53) internal diameter; The back segment inwall of urceolus has an annular protrusion (54), and its internal diameter is less than the diameter of push rod back segment ring segment (16).

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