CN101203258B

CN101203258B - Improved controlled retraction syringe and plunger therefor

Info

Publication number: CN101203258B
Application number: CN2006800163835A
Authority: CN
Inventors: J·H·卡尔; C·S·索利; D·贾德
Original assignee: Unitract Syringe Pty Ltd
Current assignee: Unitract Syringe Pty Ltd
Priority date: 2005-05-12
Filing date: 2006-05-11
Publication date: 2011-01-19
Anticipated expiration: 2026-05-11
Also published as: ZA200709607B; CN101203258A

Abstract

A retractable syringe (10) and plunger (20) therefore are provided, the syringe having a barrel (20), a retractable needl mount (40) to which is mounted or is mountable a needle (11), and a plunger (80), the plunger comprising an initially compressed spring (60), a means for engaging the retractable needle mount, an integrally formed plunger seal (22) and a removable controlling means (70) for facilitating control of the rate of retraction of needle mount when engaged wit plunger. The needle mount is held in the barrel by a holding means which prevents inadvertent retraction of the needle mount when the plunger is withdrawn to fill the syringe. The holding means comprises a plurality of clips (196A, 196B, 196C) that may be integrally formed with the barrel or may be present on a cap mounted to the barrel. An ejector means (52) is also provided, whereby plunger depression can urge the ejector means to release the needle from the holding means and thereby allow retraction of the needle mount following decompression of the spring.

Description

Improve the retractable syringe and the plunger thereof of control

Technical field

The present invention relates to syringe.More particularly, the present invention relates to comprise that controlled cam mechanism is to prevent the reusable retractable syringe of syringe.

Background technology

Continuously between the user without suitable sterilization and the behavior of shared syringe is the principal element of human immunity defective virus (HIV) and hepatitis propagation, it produces serious influence to the patient subsequently, and causes society the patient to be supported and provide the medical treatment high expense that care is produced.

Be used to prevent the reusable syringe of syringe for tackling this problem, having developed.

A solution of the syringe of being developed is in the syringe of the permanent retraction syringe of syringe needle, and by the spring driving retraction of compression, for example this scheme is described in the open WO 01/80930 in the world.For example provide the pretensioned spring of resistance to combine, can be " sensation " that the syringe user provides improvement, as described in the open WO 2004/082747 in the world by will not taking out to press to plunger.

But spring decompression is uncontrolled relatively, and in use it causes excessively strong needle retractable, when in the syringe needle retraction syringe, because air is forced to leave injector syringe, can causes blood and splash.

Another problem relevant with retractable syringe is that plunger must align with retractable needles, but so that be positioned at additional engagement device on the plunger and retractable needles does not engage before retraction, but can engage when needed to promote the retraction of syringe needle.

Thisly align manufacturing cost and the selling price that true localized requirement can increase retractable syringe, this has damaged the commercial appeal of retractable syringe, especially when third world countries' large-scale production and mass marketing.

Summary of the invention

The present invention is directed to a kind of broad form of retractable syringe, it comprises the mechanism that impels needle retractable in a controlled manner.

The present invention is directed to the another kind of broad form of retractable syringe, it has the device that prevents the unexpected retraction of syringe needle.

The present invention is directed to another broad form of retractable syringe, no matter in assembling still in use, but it does not all need the alignment between retractable needles and the plunger to impel needle retractable.

In first aspect, the invention provides the plunger that is used for retractable syringe, but this syringe has syringe and retractable needles seat, this needle holder is equipped with maybe can install syringe needle, but but described plunger comprises the dismountable control device that is used to engage the device of described retractable needles seat and is used for promoting the retraction speed control of described retractable needles seat with described plug engages the time.

In second aspect, retractable syringe has syringe; But the retractable needles seat, this needle holder is equipped with maybe can install syringe needle; And plunger, but this plunger comprises the device that is used to engage described retractable needles seat and detachable control device, but to be used for described plug engages the time, promoting the retraction speed control of described retractable needles seat.

In the third aspect, the invention provides the method that a kind of operation has the retractable syringe of syringe; But the retractable needles seat, this needle holder is equipped with maybe can install syringe needle; And plunger, this plunger comprises the device that is used to engage described retractable needles seat and detachable control device, this method comprises the step of operating described detachable control device, but with described plug engages the time, to control the retraction speed of described retractable needles seat.

In fourth aspect, the invention provides a kind of method of making as described plunger of front several respects or syringe, wherein said plunger inserts described syringe, but and the retractable needles seat alignment that does not make described plunger and engage.

Rightly, plunger comprises plunger seal pad (seal), plunger shell and plunger part.

Preferably, described plunger seal padding body forms or contacts with described plunger shell, for example by mold insert molding on described plunger shell (insert moulding).

Typically, integrally formed plunger seal pad especially is suitable for " refilling type (fill-able) " syringe (rather than pre-filled (pre-filled) syringe), because it provides simpler and method at a low price for making and assemble described retractable syringe, enough sealing effectiveness have been kept simultaneously.

Preferably, plunger also comprises bias unit, and in use described plunger shell and described plunger part combined effect are to remain on initial compressed state with described bias unit releasedly.

Described bias unit is spring, elasticity or other compressible and can reduce pressure structures.

Preferably, described bias unit is a spring.

In a preferred form, retractable syringe also comprises bracing or strutting arrangement, thereby but its engage with described needle holder releasedly and prevent retractable needles seat retraction during plunger withdrawal.

In one embodiment, bracing or strutting arrangement comprises that integral body is formed at the propclip in the described syringe.

In another embodiment, bracing or strutting arrangement comprises propclip in being installed to the lid of described syringe.

Suitably, syringe also comprises injection apparatus (ejector means), and it operationally discharges the described bracing or strutting arrangement that engages with described needle holder, thereby allows the retraction of described needle holder.

In a preferred embodiment, in the use, after described plunger part engages described needle holder, the decompression that separately is beneficial to described spring of described plunger shell and described plunger part, thereby when described spring engaged with described plunger part and described needle holder, the decompression of described spring made described plunger part and described needle holder bounce back.

Suitably, but plunger also be included in before the described retractable needles seat retraction, be used for described control device is releasably connected to the holding device of described plunger shell.

Preferably, using method is included in the step of retraction end back from plunger dismounting control assembly.

In a preferred form, described control device is a control stick.

In this description, except as otherwise noted, " comprising ", " comprising " and " containing " are opening rather than exclusive, and therefore the integer or the integer group of statement can comprise one or more integers that other are not stated or integer group.

Description of drawings

With the accompanying drawing is with reference to description non-limiting example of the present invention, wherein:

Fig. 1 is the cutaway view of the embodiment of retractable syringe;

Fig. 2 is the side sectional view of the embodiment of plunger, has shown the compression spring between preceding plunger part of retraction and the plunger shell;

Fig. 3 is the side sectional view of the embodiment of plunger, has shown the plunger rod that engages with latch in the preceding plunger shell of plunger rod retraction;

Fig. 4 is the vertical view of plunger part, has shown the needle holder engagement device;

Fig. 5 is the side sectional view of the embodiment of needle holder, seal member and injection apparatus;

Fig. 6 is the cutaway view of syringe, has shown the needle holder that engages before the retraction;

Fig. 7 is the plunger cutaway view, and this plunger engages with needle holder before retraction;

During Fig. 8 is needle holder, plunger part and plunger rod retraction, the side sectional view of retractable syringe;

After Fig. 9 is retraction, has the side view of the retractable syringe of the control stick that is disengaged;

Figure 10 is the cutaway view of the embodiment of retractable syringe, has shown the lid that is installed on the syringe;

Figure 11 is the side sectional view of the embodiment of syringe lid, needle holder and seal member;

Figure 12 is the vertical view cutaway drawing of the embodiment of syringe lid;

Figure 13 is the inner side view of lid;

Figure 14 is the axonometric chart of the alternate embodiment of syringe needle and needle holder;

Figure 15 is the axonometric chart of the alternate embodiment of syringe needle, needle holder and seal member;

Figure 16 is the axonometric chart of the alternate embodiment of syringe, and this syringe comprises integrally formed bracing or strutting arrangement; And

Figure 17 is the cutaway view of the alternate embodiment of plunger.

The specific embodiment

With reference to figure 1, retractable syringe 10 comprises plunger 20 and syringe 30.Syringe 30 comprises plunger end 31, needle end 32, inwall 33 and is positioned at dactylostyle (finger grip) 34A, the 34B of plunger end 31.In the needle end 32 of syringe 30, but the retractable needles seat 40 with syringe needle 11 is installed, this syringe needle 11 comprises hollow needle mounted thereto (cannula) 12, and is assemblied in the seal member 50 in the circumferential groove 39 in the inwall 33.

Plunger 20 can axially-movable in the fluid space 500 of syringe 30, and it comprises plunger shell 21, control stick 70 and the plunger part 80 with plunger seal pad 22.Control stick 70 has button 71, and button 71 is operated by user, and is assemblied in the latch 28 of going in ring, and this belt latch 28 is assemblied in the inward flange 299 of plunger shell 21, as shown in Figure 3.

More obvious among Fig. 2, plunger shell 21 is hollow basically, comprises inwall 23 and the cervical region 24 with inner periphery shoulder 25A, 25B.Plunger part 80 comprises excircle lug (ledge) 81A, 81B and has the inner chamber 82 of ring 83 that ring 83 receives also the additional piece 72 of Engagement Control bar 70 releasedly.

Plunger seal pad 22 integral body form or contact with plunger shell 21, preferably by mold insert molding in plunger shell 21, thereby the seat 27 of plunger seal pad 22 is sealed on the cervical region 24 of plunger shell 21, and bear against plunger part 80 at intersection 26, the fluid-tight between the inwall 33 of

plunger seal parts

222A, 222B and syringe 30 also is provided simultaneously.

Compression spring 60 is installed on the plunger part 80, is supported between the inner periphery shoulder 25B of inwall 23 of the excircle lug 81B of plunger part 80 and plunger shell 21.The excircle lug 81A of plunger part 80 bears against the inner periphery shoulder 25A of plunger shell 21, thereby keeps releasable joint between plunger shell 21 and plunger part 80.

As shown in Figure 3, by bearing against the alligator clamp 75 at the inner periphery shoulder 29 of the latch 28 of going in ring, the button 71 of plunger rod 70 engages with belt latch 28 at first.The latch 28 of going in ring is assemblied in the inward flange 299 of plunger shell 21, thereby prevents plunger rod 70 from 21 unexpected the disengagings and retraction of plunger shell, and therefore, the spring driving retraction up to plunger rod 70 all needs plunger part 80 always.

With reference to figure 4, plunger part 80 also comprises needle holder engagement device 84, and this needle holder engagement device 84 comprises a plurality of

protrusion member

85A, 85B, 85C that separated by

gap

87A, 87B,

87C.Protrusion member

85A, 85B, 85C are formed by elastomeric material, thereby can do the radially inwardly motion shown in solid arrow.

With reference to figure 5, needle holder 40 comprises the main body 42 of (the luer mount) 41 that have Rule seat, Rule seat 41 has locking screw thread 43 and medium pore 44, and this medium pore 44 allows to be installed in the fluid communication between the flowing material of syringe needle 11 (not shown among Fig. 5) on Rule seat 41 and syringe 30.

In an alternate embodiment, Rule seat 41 can be no screw thread female Luer (luerslip) (not shown) form, as known in the art.

In another alternate embodiment, the present invention is contemplated that the retraction of fixed needle 11 rather than the retraction of the syringe needle 11 that can removably install, will more specifically describe hereinafter.

The medium pore 44 of needle holder 40 is communicated with the fit 45 of the needle holder engagement device 84 that holds plunger 20, is beneficial to the retraction of needle holder 40 and the syringe needle that engages.

Needle mount body 42 also comprises toothed edge 46, and it comprises a plurality of tooth 47A to 47L and needle holder matrix 49.

Seal member 50 comprises sealing matrix 51, and this matrix 51 comprises sealing ribs 56A, the 56B that is separated by waist 55, the injection apparatus 52 and the needle holder passage 54 of taper anchor ring 53 forms.

Seal member 50 is assemblied in around the needle holder matrix 49.

With reference to figure 6, the circumferential groove 39 of syringe 30 is assemblied in the waist 55 of seal member 50, to prevent that seal member 50 is by in the indentation syringe 30.

Clearly, the tooth 47A to 47L of the toothed edge 46 of needle mount body 42 presss from both sides 35A to 35F with the guiding in the syringe 30 and interacts, and is beneficial to the location of needle holder 40 in the needle end 32 of syringe 30 in Fig. 6.Each guiding folder 35 has guiding tooth 37, and in assembling process, by engaging contiguous tooth 47, this guiding tooth 37 helps needle holder 40 to be fitted into the needle end 32 of syringe 30.In Fig. 5 and example shown in Figure 6, the tooth 37A of

tooth

47A, 47B and guiding folder 35A interacts, and

tooth

47E, 47F and the tooth 37C of guiding folder 35C interact, although be interpreted as any a pair of adjacent tooth 47 can with any guiding folder 35 interactions.

When additional screw thread syringe needle was installed to Rule seat 41 by locking screw thread 43, this layout had also prevented the rotation of needle holder 40.

The needle end 32 of syringe 30 also comprises propclip 36A to 36F, the downside 48 of the toothed edge 46 of its joint pin headstock 40, and prevent that needle holder 40 is before retraction in the unexpected retraction syringe 30.

Propclip

36A, 36D are as shown in Figure 6.Propclip 36A to 36D is suitably formed by the material of elastically deformable, thereby propclip 36A to 36D can from the engaging of needle holder 40 discharge, to such an extent as to but be out of shape not too large before retraction in the retraction process of plunger 20 propclip 36A to 36D unexpectedly break away from and the engaging of needle holder 40.

With reference to figure 7 and Fig. 8, in use the order of occurrence of each incident is as described below.

Though be not exclusiveness ground, syringe 10 typically can discharge 3 or 5 milliliters of Fluid Volumes.Thereby plunger part 80 joint pin headstock 40 unexpectedly not before the retraction, syringe 30 have enough volumes with allow plunger 20 retractions with near the initial position of needle holder 40 plunger end 31 of syringe 30 (promptly towards) with fluid filled to syringe 30.

In case fill, realize the injection of the flowing material of syringe 30 by compression plunger 20.

For from fluid space 500 release fluids compression plungers 20 when finishing, the additional fit 45 of needle holder engagement device 84 snap lock (snap-lock) the joint pin headstock 40 of plunger part 80, thus connect needle holder 40 and plunger part 80.This be by with the device 84 needle holder that engage

protrusion member

85A, 85B, 85C can radially inwardly be moved into

gap

87A, 87B, 87C (shown in filled arrows among Fig. 4) realizes, replenish fit 45 thereby be beneficial to enter and engage, as shown in Figure 7.

Continue compression plunger 20 by the filled arrows direction in Fig. 7, by being connected to the plunger seal pad 22 of the plunger shell 21 that bears against sealing matrix 51, the taper injection apparatus 52 of seal member 50 is pushed to the needle end 32 of syringe 30.When plunger part 80 linked to each other also stop motion temporarily with needle holder 40, plunger seal pad 22 and plunger shell 21 continued to move along this direction.

Seal member 50 and taper injection apparatus 52 allow injection apparatus 52 to make propclip 36A to 36F radially outward move (shown in filled arrows among Fig. 6) and are disengaged with the downside 48 of the toothed edge 46 of needle holder 40 to the persistent movement of the needle end 32 of syringe 30, thereby the needle end 32 of needle holder 40 from syringe 30 discharged, and this needle holder 40 is connected to plunger part 80 as previously described.

Continue continuous compression plunger 20 gently, plunger part 80 is disengaged with plunger shell 21.This excircle lug 81A inner periphery shoulder 25A from the cervical region 24 of plunger shell 21 by plunger part 80 breaks away from and connects, and realizes with the joint that discharges between plunger shell 21 and the plunger part 80.

Thereby this disengaging makes the excircle lug 81B of spring 60 decompression backup plunger parts 80, thereby direction of arrow retraction plunger part 80 and the needle holder 40 that is connected with plunger part 80 in plunger shell 21 keeps seal member 50 and plunger seal pad 22 static simultaneously in Fig. 8.Equally, spring 60 times, thus being disengaged along the inner periphery shoulder 29 that the direction of arrow shown in Fig. 3 moves with latch by alligator clamp 75, the latch 28 of pressure control stick 70 from be assemblied in plunger shell 21 breaks away from.Like this, plunger rod 70 retractions, retraction speed is by user applied pressure (for example by the thumb pressurization) control on control knob 71.

As the lug 81B of plunger part 80 during in abutting connection with latch 28, retraction finishes.

Plunger shell 21, plunger seal pad 22 and seal member 50 do not bounce back, and remain on the needle end 32 of syringe 30.

As shown in Figure 9, can manually control stick 70 be dismantled from syringe 10 then.Control stick 70 can be used as " cleaning " rubbish and abandons, and stays the syringe 10 that remnants in the syringe 30 have plunger shell 21, plunger seal pad 22 and seal member 50, to handle through medical waste more closely.

Figure 10 to 13 has shown alternate embodiment, and wherein retractable syringe 110 comprises plunger 120 and syringe 130.Syringe 130 comprises plunger end 131, needle end 132, inwall 133 and is positioned at dactylostyle 134A, the 134B of plunger end 131.In the needle end 131 of syringe 130, but the retractable needles seat 140 with syringe needle 111 is installed, this syringe needle 11 comprises hollow needle 112, lid 190 and seal member 150.

Plunger part 180 comprises needle holder engagement device 184, and this needle holder engagement device 184 comprises protrusion member 185A, the 185B that is separated by gap or space 187, the fit 145 that it can joint pin headstock 140.

But describe in more detail with reference to Figure 11 and to cover 190 retractable needles seats 140 and seal member 150.

Lid 190 comprises lid 191, matrix limit 192, lid 193 and hole, Rule (lueraperture) 194.Lid 191 comprises and separately propclip 196A, 196B, space 195A, the 195B of 196C associated, 195C.Space 195B, the 195C of

propclip

196B, 196C and correspondence are invisible in Figure 11, but can be more clearly visible in Figure 12 and Figure 13.

Refer again to Figure 11, needle holder 140 comprises the main body 142 with Rule seat 141, this Rule seat 141 has locking screw thread 143 and medium pore 144, and this medium pore 144 allows to be installed in the syringe needle (not shown) of Rule seat 141 and the flowing material of syringe 130 carries out fluid communication.In an alternative embodiment, Rule seat 141 can be the form of no screw thread female Luer (not shown), as known in the art.

Medium pore 144 is communicated with the fit 145 of the needle holder engagement device 184 that holds plunger 120, is beneficial to the retraction of needle holder 140 and the syringe needle that engages, as previously described.

Needle mount body 142 also comprises toothed edge 146 and needle holder matrix 149, and this toothed edge 146 comprises a plurality of teeth 147 and limit downside 148.

Seal member 150 comprises the injection apparatus 152 of sealing matrix 151 and taper anchor ring 153 forms, and needle holder opening 154.

Seal member 150 is assemblied in around the needle holder matrix 149, and part is in lid 190 inside, and this lid 190 is installed on the needle mount body 142, thereby seat 141 outstanding passing in Rule are covered 190 hole, Rule 194.

According to present embodiment, provide and comprised and cover 190

propclip

196A, 196B, the bracing or strutting arrangement of 196C, inwardly the location is with the downside 148 of adjacency toothed edge 146, thereby needle holder 140 is towards plunger end 131 motions of syringe 130 when preventing that plunger is drawn back in syringe 110 filling processs.

Lid 190

propclip

196A, 196B, 196C can radial and outward deformation, shown in filled arrows among Figure 13, so that needle holder 140 discharges.

The tooth 147 of the toothed edge 146 of needle mount body 141 interacts below lid 190 with

complementary teeth

197A, 197B, 197C, as shown in figure 12, thereby is replenishing the rotation that prevents needle holder 140 when the screw thread syringe needle is installed to Rule seat 141 by locking screw thread 143.

As previously mentioned, after the plunger part 180 joint pin headstocks 140, continue compression plunger 120 and the taper injection apparatus 152 of seal member 150 is pushed to the needle end 132 of syringe 130, so that injection apparatus 152 impels axially outwards motion (shown in filled arrows among Figure 13) of

propclip

196A, 196B, 196C, and be disengaged with the downside 148 of the toothed edge 146 of needle holder 140, thereby discharge the needle holder 140 that is connected with plunger part 180, as previously described.

It is as mentioned below in essence that the decompression of spring 160 and needle holder 140 and its are gone up the controlled retraction of syringe needle 111 of installation.

Though be not exclusiveness ground, aforementioned preferred embodiments typically relates to retractable syringe 10, wherein syringe needle 11 can be installed to needle holder 40 by female Luer or female Luer (luer lock).

Figure 14 to Figure 17 has shown the alternate embodiment with fixation hollow pin 211.

According to this embodiment, especially with reference to Figure 14, hollow needle 211 is bonded to or co-molded (co-moulded) in needle holder 240.Needle holder 240 comprises plug engages device 245A, the 245B of main body 242, matrix 249 and barb-like form with limit 246.

With reference now to Figure 15,, injection apparatus 252 co-molded are on seal member 250.Seal member 250 is used for sealing the inwall 233 of syringe 230 by sealing ribs 256A, the 256B that is separated by waist 255 and is used for sealing needle holder 240 on the matrix 249.The advantage of this layout is that fixed needle 211 typically has the diameter littler than female Luer or female Luer needle holder 240, has therefore reduced the integral diameter of syringe 210.

With reference now to Figure 16,, in the needle end 232 of syringe 230, bracing or strutting arrangement comprises the propclip in a plurality of collars 239 that are overmolded to syringe 230.

Propclip

236A, 236B, 236C, 236D joint pin headstock 240 are to prevent needle holder 240 unexpected retractions when drawing back plunger 220 and think syringe 210 fill

fluids.Guiding folder

235A, 235B, 235C, 235D global formation in the syringe collar 239 of syringe 230, and each guiding folder 235 has lug 237, in assembling, this flange 237 promotes that needle holder 240 is fitted into the needle end 232 of syringe 230, and prevents the mobile needle end 232 that exceeds of needle mount body by the limit 246 of joint pin headstock 240.

According to this embodiment, especially with reference to Figure 17, plunger 220 comprises plunger shell 221, plunger part 280 and plunger seal pad 222.Plunger seal pad 222 co-molded and comprise sealing

ribs

2222A, 2222B on plunger shell 221.

Needle holder engagement device 284 is the grooves in the plunger part 280, and

barb

245A, 245B that it is suitable for holding needle holder 240 are beneficial to the retraction of needle holder 240, as previously mentioned.

The seat 227 of plunger seal pad 222 is sealed on the cervical region 224 of plunger shell 221, and bears against plunger part 280 at intersection 226, also provides fluid-tight between

plunger seal parts

2222A, 2222B and syringe 230 simultaneously.

The spring 260 of compression is installed on the plunger part 280, is supported between the inner periphery shoulder 225B of inwall 223 of excircle lug 28 1B of plunger part 280 and plunger shell 221.The excircle lug 281A of plunger part 280 bears against the inner periphery shoulder 225A of plunger shell 221, thereby keeps releasable joint between plunger shell 221 and plunger part 280.

Yet in specific embodiment, the circumference lug 281A of plunger part 280 and/or the internal lobes 225A of plunger shell 221 can for example be comprised two, three, four, five or six circular segment by segmentation.Preferably, every section can have identical length.

Expect that this segmentation layout can provide interference fit more closely, even thereby have the tolerance variation that often occurs in the injection molding, connect the compression that also enough can keep spring 260 by force, connect but need less power that plunger part 280 is broken away from from plunger shell 221, therefore make spring 260 can reduce pressure and be beneficial to the retraction of needle holder 240 and hollow needle 21.

According to noted earlier, should be appreciated that and the invention provides simple, durable and cheap relatively retractable syringe, it does not need the auxiliary of user or needs the auxiliary of user to scrap automatically hardly, therefore prevents or has reduced the reusable probability of syringe at least.

In addition, the speed by the control needle retractable has reduced the probability that blood splashes, thereby has improved " user friendly " of retractable syringe.

The special advantage of retractable syringe of the present invention is, plunger does not need to rotate to needle holder and aligns to allow the retraction of needle holder.

In addition, injection apparatus is symmetric, does not therefore need to align to realize the release of needle holder with propclip.

Therefore, need not the location and greatly simplified manufacturing, thereby reduced the manufacturing cost and the selling price of syringe.

In whole description, purpose is to describe the preferred embodiments of the present invention, and does not limit the present invention in the particular combinations of any one embodiment or feature.Do not deviating under the prerequisite of the present invention, can make various changes and modification the embodiment that describes and illustrate.

Claims

1. plunger that is used for retractable syringe, but this syringe has syringe and retractable needles seat, this needle holder is equipped with maybe can install syringe needle, but but described plunger comprises bias unit, plunger shell and plunger part, is used to engage the device of described retractable needles seat, with the integrally formed plunger seal pad of described plunger shell and the dismountable control stick that is used for described plug engages the time promoting the retraction speed control of described retractable needles seat, and plunger shell and plunger part combined effect remain on initial compressed state with described bias unit releasedly.

2. plunger as claimed in claim 1, wherein plunger seal pad mold insert molding in described plunger shell.

3. plunger as claimed in claim 2 arranges that this plunger makes described plunger part allow the decompression of described bias unit from the release of described shell, with when described plunger part joins described needle holder to, but promotes the retraction of described retractable needles.

4. plunger as claimed in claim 3, but further comprise the holding device that is used for before described retractable needles seat retraction, releasedly described control stick being connected to described plunger shell.

5. plunger as claimed in claim 4 is arranged that this plunger makes the decompression of described bias unit impel described holding device to be disengaged, thereby is allowed described control stick to discharge from described plunger shell.

6. plunger as claimed in claim 5, wherein said bias unit is a spring.

7. a retractable syringe has syringe; But the retractable needles seat that syringe needle maybe can be installed is installed; And plunger, but but this plunger comprises bias unit, plunger part and plunger shell, is used to engage the device of described retractable needles seat, with the integrally formed plunger seal pad of described plunger shell and the dismountable control stick that is used for described plug engages the time promoting the retraction speed control of described retractable needles seat, and plunger part and plunger shell combined effect remain on initial compressed state with described bias unit releasedly.

8. retractable syringe as claimed in claim 7, wherein plunger seal pad mold insert molding in described plunger shell.

9. retractable syringe as claimed in claim 7 further comprises bracing or strutting arrangement, and this bracing or strutting arrangement engages described needle holder releasedly, thereby but prevents the retraction of retractable needles seat in plunger withdrawal process.

10. retractable syringe as claimed in claim 9, wherein said bracing or strutting arrangement comprise that integral body is formed at the propclip in the described syringe.

11. retractable syringe as claimed in claim 10, wherein said bracing or strutting arrangement comprises propclip in being installed to the lid of described syringe.

12. retractable syringe as claimed in claim 10, wherein said syringe further comprises injection apparatus, this injection apparatus operationally make described bracing or strutting arrangement from the engaging of described needle holder discharge, thereby allow the retraction of described needle holder.

13. retractable syringe as claimed in claim 12, arrange this retractable syringe so that the release of described plunger part from described shell makes described bias unit reduce pressure, but when described plunger part joins described needle holder to, to impel the retraction of described retractable needles.

14. retractable syringe as claimed in claim 7, but further comprise the holding device that is used for before described retractable needles seat retraction, releasedly described control stick being connected to described plunger shell.

15. retractable syringe as claimed in claim 14 is arranged that this retractable syringe makes the decompression of described bias unit impel described holding device to be disengaged, thereby is allowed described control stick to discharge from described plunger shell.

16. retractable syringe as claimed in claim 7, wherein said bias unit is a spring.

17. retractable syringe as claimed in claim 7 further comprises: bracing or strutting arrangement, it engages described needle holder releasedly, thereby but prevent the retraction of retractable needles seat in the process of withdrawal plunger; Injection apparatus, its operationally make described bracing or strutting arrangement from the engaging of described needle holder discharge, thereby allow the retraction of described needle holder; But and the holding device that is used for before described retractable needles seat retraction, releasedly described control stick being connected to described plunger shell.