WO2008136775A2

WO2008136775A2 - A safety syringe

Info

Publication number: WO2008136775A2
Application number: PCT/SG2008/000162
Authority: WO
Inventors: Jun Piao Teng
Original assignee: Jun Piao Teng
Priority date: 2007-05-08
Filing date: 2008-05-05
Publication date: 2008-11-13
Also published as: SG148042A1; WO2008136775A3

Abstract

A safety syringe comprises: a hollow barrel, a plunger with a piston, a hard rubber adaptor, and a needle. The piston includes a rubber element having a central room space to allow the plunger tip to move axially therein for performing functions to enable drawing fluid starting at Occ level and interlocking respectively. The adaptor affixed at a distal protruding nose of the barrel and the needle is locked at a threaded portion within the adaptor snugly, which includes a female interlocking structure at proximal end to receive a male interlocking structure aligning a loosen means of the plunger, characterized in that the male interlocking structure is loose staying within, carrying the adaptor with the needle into the barrel upon retracting the plunger, in the manner that the loosen adaptor declines together with the needle causing the needle tip declined and is abutted by the base within. Further pulling the plunger, the piston is abutted by the abutting structure of the barrel allowing the plunger to break at a fragile portion provided, thereby absolutely ensuring non-reusable and avoid needle stick injuries.

Description

Patent Application of

Teng Jun Piao

For

A SAFETY SYRINGE

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates in general to a novel safety syringe, which has medical and industrial application. More particularly, the present invention pertains to a syringe which after injecting medication into a patient, or withdrawing fluids from a patient in medical field, or transfer of toxic materials in industrial field, or the like, is useful for retracting the spent needle into its barrel, thereby avoiding the users from needle stick injuries.

2: BACKGROUND OF THE INVENTION

This invention more relates to medical equipment, and more particularly to a safety syringe designed to prevent accidental needle stick injuries by medical personnel, for example during injection of medication or drawing of a blood specimen of a patient.

The ever increasing spread of diseases transmitted by blood and other bodily fluids, such as Acquired Immune Deficiency Syndrome and Hepatitis B creates a real threat to medical personnel of accidental, inadvertent puncturing of the skin by an injecting needle which has been in contact with an infected patient and of the transmittal of the often fatal disease to the unfortunate medical attendant. Despite educational programs carried by many hospitals, accidents continue to happen with an unfortunate effect of medical personnel being infected through coming in contact with bodily fluids of a patient.

Various attempts on design have been made to resolve this problem such as: by complicated parts integration to retract or cover the spent needle manually or by springy material automatically after use. However, most of prior arts either are only on technical theory but not work in practical production, or are too complicated involving too many parts to assemble together forming a "robot" look like rather than a disposable syringe, resulting commercially not viable finally, because traditional disposable syringe has been existing for over 50 years worldwide since the 2^nd World War, usually only simply contains 2 to 3 parts (excluding needle), namely: plunger, barrel and rubber stopper which because of simple in assembling, can be on mass production for million pieces per day by a series of more simple and more economic automatic machines, therefore its production cost is cheap, which is not over @US 2 cents each according to the inventor's practical production experience, and people have already got used to be its cheapness is a fact.

Furthermore, disposable syringe manufacturers are easy to buy an economic robotic machines for automatic assembling from A to Z of their traditional disposable syringe (about US$70,000 per set made in China), but if asking the machine manufacturer to help to build one unique robotic machine for a special designed syringe which if under patent having too many parts to assemble, they usually either refuse or ask for a considerate amount of design fee (at least US$300,000 according to the inventor's experience) plus machine cost etc., due to patent coverage, they cannot sell this unique designed machine anywhere, and further, they are afraid that after the first machine is toughly researched and developed successfully, the customer will ask the other supplier to copy for second one onward. This undoubtedly will add a heavy burden of production cost on the complicated safety syringe when manufacturing.

Presently, the professional users usually more prefer to use luer lock disposable syringe than the ones of slip tip, because they feel more safe on locking, and prefer to change their own preferable needle to use for injection. Most of prior arts do not have this feature especially for those automatic retracting ones. Furthermore, as earlier said, the professional users have got used to use the traditional disposable syringes everyday for over half of century, and they generally treat the injection is only a very small matter, but it also must be very careful, therefore, if possible they prefer to use a safety syringe which application ways are absolutely the same as the traditional disposable syringes which they get used to, so that they can handle it with ease and more confidence without necessary to worry that this is a new syringe which is strange for their usually using. But unfortunately, one minor feature, that is: the "dose starting level", all existing retractable safety syringes cannot start at Occ level to draw up medication because they must need a hook or some other structural mechanism(s) to interlock with the luer or needle hub for retraction, so that the hook or the mechanism therein must have a gap distance far from the line of Occ level before interlocking, causing that it is impossible to draw up the medication accurately therefrom. Conclusively, some of prior art's application ways differ from the traditional disposable syringe's, or difficult to use requiring several steps in preparation of the syringe device for utilization, so far, have not found wide acceptance in the medical profession. But the present invention can overcome all of the above- mentioned difficulties, it is a safety syringe, but its application ways from A to Z are exactly the same as the traditional disposable syringe including the "Occ starting problem" which should be welcome by the medical professionals. A number of patents disclose syringes or the like having needle protecting features, such as:

U.S. Pat. No. 4,592,744, Jagger et ah, June 3, 1986, illustrates a disposable medical needle apparatus with a self-sheathing safety needle assembly. The self sheathing safety needle has a case with a small closed end and a large open end. A needle assembly is located within the case with the needle projecting through the small closed end. A hub is connected to the needle assembly inside the case. The connector on the hub cooperates with a receiver on the small end to hold the needle assembly in the case. A flange on the hub cooperates with an inward projection in the case based from the small end to prevent movement of the needle out of the case when the needle is withdrawn from the opening in the small end. The nozzle of a syringe pushed into the hub withdraws the needle when the syringe is withdrawn. A rubber stopper on a vacuum tube withdraws the needle after the rubber stopper turns the flange to release the connector from the receiver.

U.S. Pat. Nos. 4,542,749, Caselgrandi et al., and 3,306,290, Weltman, disclose syringes with protected needle designs.

U.S. Pat. No. 4,774,964 discloses a device which is designed to withdraw blood from a patient. It is not a syringe per se. It is not used for injecting fluids into a patient. However, the device has the capacity to withdraw the needle into the barrel housing.

U.S.Pat. No. 6,033,386 diclose a device which involves different alternative methods to screw or turn the plunger for retraction of the needle after use. U.S. Pat. No. 6,869,415 disclose a device which needle to be retracted by a tension spring.

The present invention contemplates elimination of drawbacks associated with prior art and provision of an improved and economic safety syringe which only increases with one additional part comparing with traditional disposable syringe, that is: rubber luer lock. Its material is specifically mixed with latex free rubber and medical plastic, which is adapted to strengthen its hardness close to plastic characteristic, so as to let the traditional needle hub to lock in exactly like existing PP luer lock disposable syringe does, but remaining its elastic characteristic like rubber in order to avoid using one more part of rubber O-ring to avoid leakage which will undoubtedly increase the considerate production cost as explained above. The rubber stopper is specifically designed, it can hid the intruder within the stopper before injection, and the intruder can be released for interlocking the luer upon pushing further for retraction, so as to let the users can start drawing up the medication at the Occ level like the traditional disposable syringe, and can retract the needle into its barrel after injection for fulfilling the required safety function. (Note from the inventor: Successful R&D luer lock and stopper samples can be provided for evidence if required). Except luer lock, rest three parts of present invention, namely: barrel, plunger and rubber stopper are only the structural designs not the same as existing disposable syringe, but similarly each part can be built within one mould in order to save additional mould cost, material cost and also because of same reason, its robotic assembling cost is economic quite close to the existing traditional disposable syringes.

In conclusion, the present invention is particularly adapted for non-reusable and preventing the user from needle stick injuries as well after injection of medication or drawing blood from a patient and which application way is exactly the same as traditional disposable syringe which the users most prefer, with simple improved structural designs like the ways of existing disposable syringe to manufacture, thereby minimizing the production cost practically for commercially viable, further resulting to achieve minimizing the spread of diseases finally.

3. SUMMARY OF THE INVENTION

Accordingly, it is a primary object of the present invention to provide a safety syringe by only adding one component of rubber luer lock (which can be change of needle before use) with some specific structural designs on the barrel, plunger, and rubber stopper (gasket) similar to traditional disposable syringe, with which the user is able to avoid from being injured by the needle during the process of injection or drawing blood.

According to the most general aspect of the present invention there is provided a safety syringe comprising: (a) a hollow elongated barrel means with a smaller distal opening at one end and a bigger proximal opening at other end;

(b) a traditional hollow needle carrier ended with a sharp tip engaged with a hub which the users prefer to use is adapted to detachably engage at distal end of the barrel means enabling to penetrating into human body for collecting fluid (usually is blood), which can be retracted into the hollow barrel means after use in order to prevent needle stick injuries;

(c) a plunger which is adapted to fit within and move axially in the hollow barrel means; particularly in the present invention, includes a push button at proximal end, a shaft connecting to a gapped fragile portion with a piston extending forwardly a supporting means and a loosen means attached to a male interlocking means at distal end;

(d) a soft rubber element which is adapted to act as the piston, having a smaller distal opening at one end and a bigger proximal opening at other end, with a plurality of parallel seals lying separately and externally at the midst, characterized in that there is a specified room space within the central hole to let the plunger tip move axially to and fro therein;

(e) an adaptor made of harder but elastic rubber material which is adapted to engage internally at the distal opening end of the barrel means where the hollow needle is screwed detachably therein, which when after injection, to be interlocked with the male interlocking means of the plunger, thereby carrying the needle carrier into the interior of barrel means upon retraction of the plunger. Preferably, a barrel means comprising: a smaller distal opening with a protruding nose at one end and a bigger proximal opening with a finger grip at other end, lying an abutting means internally adjacent to the proximal opening end of the barrel means which is to abut the plunger withdrawal out of the barrel means, and one luer catch means located internally at one end of the protruding nose where a several linear female protuberances are disposed at the midst in vertical and separated manner spread evenly within the protruding nose therein. Preferably, the gapped fragile portion of the plunger allowed to break therein, when the piston is trapped within the barrel means, thereby ensuring the syringe cannot be reused again, and the male interlocking means of the plunger is supported by the loosen means to be inserted into a female interlocking means of the adaptor through a central hole therein, characterized in that the interior room of the female interlocking means is provided bigger than the male interlocking means and the central hole's diameter is bigger than the loosen means of the plunger also, whereby the adaptor will be loosen and declined at its distal end with the needle carrier mounted therein leaning against the inner wall of the barrel means when the adaptor is withdrawn out of the protruding nose into the interior of the barrel means upon retraction of the plunger.

Preferably, the supporting means which is located in the proximity of the loosen means, provided for abutting the rubber element moving forward when assembling into the barrel means, so as to maintain the distal seal of rubber element at the expected position lying against the line of Occ level for drawing the fluid, and further, after fully injection, it will be inserted into the rubber element, so that it also can abut the rubber element to move backward upon retraction of the plunger, enabling the adaptor has sufficient gap to let the needle carrier swing leaning against the inner wall of the barrel means.

Preferably, the adaptor is fixed snugly against the luer catch means within the interior of the protruding nose of the barrel means, including a threaded portion within, whereby the projected flange of the needle hub can be screwed snugly and detachably into the adaptor therein, and a several male protuberances are disposed at the midst in vertical and separated manner spread evenly on the external surface of the adaptor, adapted to be abutted by the female protuberances of the protruding nose therein, whereby the adaptor will not be slippery towards either direction of clockwise or anticlockwise, so that it indirectly increases the strength of the adaptor to receive the needle hub when the hub flange is being screwed into the adaptor therein.

4. BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings which illustrate a specific embodiment of the invention, but which should not be construed as restricting the spirit or scope of the invention in any way:

FIGS. Ia - Ie are perspective views illustrating the dismantled parts of an embodiment of a safety syringe comprises a hollow cylindrical shaped barrel

(FIG. Ia), a plunger (FIG. Ib), a rubber gasket (FIG. Ic), a rubber luer lock (FIG.

Id) and a needle carrier (FIG. 1 e) respectively.

FIG. 2a is a cross-sectional view illustrating the hollow cylindrical shaped barrel of the embodiment of the safety syringe, which includes: a finger grip, a proximal opening, a primary circular rim-like catch, a base of the body, a luer catch, a protruding nose, a female protuberances and a distal opening.

FIG. 2b is a top sectional view illustrating the female protuberances within the protruding nose of the barrel.

FIG. 3a is a cross-sectional view illustrating the rubber luer lock of the embodiment of the safety syringe which includes: a supporting seal, a central hole, a female interlocking notch, a nozzle, a nozzle lumen, a threaded portion and a male protuberances.

FIG. 3b is a top sectional view illustrating the rubber luer lock.

FIG. 3c is a top sectional view illustrating when the rubber luer lock is fixed within the protruding nose of the barrel.

FIG. 4a is a cross-sectional view illustrating the plunger which includes: a push button, a cross-shaped flanged shaft, a shaft flange, a gapped fragile portion, a piston primary flange, a first piston flange, a gasket support flange, a second piston flange, a central piston flange, a third piston flange, a tip supporting flange with a gap in between, and a male interlocking tip with a head.

FIG. 4b is a top sectional view illustrating the male interlocking tip of the plunger, which includes the tip, the tip head and the gap.

FIG. 4c is a cross-section view illustrating the same plunger on opposite side.

FIG. 4d is a cross-section view illustrating the rubber gasket which includes: a proximal seal, a middle seal, a distal seal, a distal central hole, a proximal central hole and a room space within.

FIG. 5 is a cross-sectional view illustrating the assembled manner of the safety syringe when the rubber luer lock is fixed snugly within the protruding nose of the barrel, and the piston primary flange with the piston is being forced across the primary catch within the barrel by the machine in the factory, characterized in that the gasket supporting flange supports the gasket, so that the whole plunger tip except the male interlocking tip is hidden inside the room space of the gasket upon assembled.

FIG. 6 is a cross-sectional view illustrating the needle carrier is screwed into the rubber luer lock within the distal opening of the assembled safety syringe, and the piston primary flange with the piston has been assembled stopping close to the central opening of the adaptor at the Occ level as marked on the barrel when preparing to use.

FIG. 7 is a cross-sectional view illustrating the operational manner when drawing fluid, the piston is withdrawn in the proximity of the primary catch within the barrel.

FIG. 8 is an enlarged partial cross-sectional view illustrating the operational manner when after fully injection of the fluid, the gasket being pushed by the plunger is abused at the base of the barrel, so that the gasket supporting flange is forced across the proximal central hole of the gasket into the room space and the central piston flange derived from the same force is also pushed forward against the distal end of the room space, and further, the male interlocking tip of the plunger is inserted through the proximal central hole of the rubber luer lock into the female interlocking notch which room and its central hole's inner diameter are specific bigger than the male interlocking tip as well as the supporting tip respectively, whereby both parts can be interlocked but the rubber luer lock can swing within the barrel after retraction.

FIG. 9 is a cross-sectional view illustrating the operational manner when the plunger is withdrawn, it retracts the rubber luer lock carrying the spent needle together in the proximity of the primary catch within the barrel, characterized in that the gasket supporting flange under this retraction force is still hidden inside the room space of the gasket to support the gasket not sliding backward to touch against the rubber luer lock body, so that the proximal end of the rubber luer lock has good enough space to be loosen, such that the needle tip is declined leaning against the inner wall of the barrel due to the swing manner of the rubber luer lock as mentioned in FIG. 8.

FIG. 10 is a cross-sectional view illustrating the final operation manner when the plunger is further withdrawn, the piston primary flange with the piston is abused at the primary catch of the barrel, thereby trapping the piston with the spent needle within the barrel, and the plunger is allowed to break at the gapped fragile portion therein upon further withdrawal.

Reference Numerals In Drawings:

10 hollow cylindrical shaped barrel (body)

11 finger grip

12 proximal opening end

13 primary circular rim-like catch 15 base of body 151 luer catch

16 protruding nose

17 female protuberance

18 distal opening end

20 plunger 201 piston

21 push button

22 cross-shaped flanged shaft

23 shaft flange

24 fragile portion

241 fragile portion gap

242 fragile connectors

25 piston supporting flange 25A distal circumferential rim 25B proximal circumferential rim

251 l ^ piston flange

25 IA gasket supporting flange

252 2^nd piston flange 252A central piston flange

253 3^rd piston flange

254 tip supporting flange (loosen means)

26 arrow-shaped male interlocking tip 26A tip head

27 tip gap

30 rubber gasket

31 proximal seal 311 middle seal

32 distal seal 33 distal central hole

34 proximal central hole

35 room space

40 needle carrier

41 needle hub flange 41 A needle hub

42 needle

43 needle tip

44 needle holder

50 rubber luer lock

51 supporting seal

52 proximal central hole 521 distal central hole

53 female interlocking notch

54 nozzle

55 nozzle lumen

56 threaded portion

57 male protuberance

5. DETAILED DESCRIPTION OF THE DRAWINGS

Referring to the drawings, FIGS. I a - Ie illustrate the perspective views of all dismantled components which make up an embodiment of the novel safety syringe comprising a hollow barrel 10, a plunger 20, a rubber gasket 30, a rubber luer lock 50, and a hollow needle carrier 40.

Barrel 10 (FIG. Ia) is a hollow elongated cylindrical shaped body having a smaller distal opening hole 18 with a protruding nose 16 disposed at one end and a bigger proximal opening end 12 at other end adjacent to a projected finger grip 11 therein. In proximity of proximal opening end 12 lying internally a primary circular rim-like catch 13. A body base 15 lying with a circular rim-like luer catch 151 in proximity at the interior of protruding nose 16 which includes a several female linear protuberances 17 in vertical and separate manner spread evenly along the inner wall of protruding nose 16 therein.

Plunger 20 (FIG. I b) having an elongated cross-shaped flanged shaft 22 with a round shaped push button 21 at proximal end, connecting to a shaft flange 23 at distal end co-aligned with a fragile portion 24 which has a gap 241 in between wherein a couple of fragile connectors 242 connecting to a piston supporting flange 25 in co-alignment with a first piston flange 251 , a gasket supporting flange 25 IA, a second piston flange 252, a central piston flange 252 A and a third piston flange 253 respectively, which extends outwardly a smaller tip-supporting flange 254 engaging with a bigger male interlocking tip 26 in arrow-shaped ended with a smaller round shaped tip head 26A wherein a gap 27 is disposed in between within tip 26 and tip head 26A.

Rubber gasket 30 (FIG. Ic) is a round shaped soft rubber body which acts as a main member of a piston 201 disposed with a distal central hole 33 at one end, and a proximal central hole 34 at other end, lying externally with a projected proximal seal 31 at one end, a middle seal 311 in the midst, and a distal seal 32 in the proximity of distal central hole 33, which internal details pis. refer to Fig. 4d. Rubber luer lock 50 (FIG. Id) is a round shaped rubber body which is made of the medical rubber raw materials mixing with some medical plastic raw materials causing its characteristic is much more harder than existing common rubber but remaining little elastic characteristic like the rubber. Luer lock 50 comprises a distal central hole 521 exposing a part of a hollow nozzle 54 with a nozzle lumen 55 at one end which elongation originated from the approximate midst within, and a proximal central hole 52 with a supporting seal 51 projected outwardly at other end. In the proximity of distal central hole 521 is disposed with a several male linear protuberances 57 which are in vertical and separate manner spread evenly on the external surface of luer lock 50, wherein a threaded portion 56 is located at the inner wall of distal central hole 521. Internally, immediate to proximal opening hole 52 is disposed with a female interlocking notch 53 which dimension is bigger than male interlocking tip 26 of plunger 20 therein, extending forwardJy a hollow passage of nozzle lumen 55 within nozzle 54 therein (to be seen on FIG. 3 a).

Needle carrier 40 (FIG. Ie) comprises a hollow needle 42 ended with a sharp tip

43 which other end is fixed with glue at a needle holder 44 penetrating a little bit within a needle hub 4 IA, adjacent to which proximal end is a projected hub flange 41 outwardly therein.

FIG. 2a is a cross-sectional view of barrel 10 which has been detailed on FIG. Ia.

FIG. 2b is a top-sectional view focusing at the portion of female protuberance 17 relating to protruding nose 16 of barrel 10.

FIG. 3a is a cross-sectional view of luer lock 50 which has been detailed on FIG.

Id.

FIG. 3b is a top-sectional view about the portions of luer lock 50 comprising distal central hole 521 with thread portion 56, male protuberances 57, nozzle 54 and nozzle lumen 55 therein.

FIG. 3c is a top-sectional view about the portion of luer lock 50 when fixing into interior of protruding nose 16, characterized in that both male and female protuberances 17 & 57 are opposed with each other therein.

FIG. 4a is a cross-sectional view of plunger 20 on one side which has been detailed on FIG. Ib.

FIG. 4b is a top-sectional view of the portion of tip head 26A relating to male interlocking tip 26 with a gap 27 in between.

FIG. 4c is a cross-sectional view of plunger 20 on opposite side characterized in illustrating that tip 26 is plain and without gap 27, and fragile connectors 242 are absence, leaving gap 241 within the area of fragile portion 24 therein. FIG. 4d is a cross-sectional view of gasket 30 illustrating the internal details therein, a room space 35 in specific depth is disposed internally within gasket 30 in between both central holes 33 & 35. (External details pis. refer to FIG. Ic accordingly.)

FIG. 5 is a cross-sectional view illustrating in assembled manner when luer lock 50 headed with supporting seal 51 is fixed snugly at interior of protruding nose 16 abutted by luer catch 151, and piston 201 supportably with flange 25 in co- alignment with fragile portion 24, shaft flange 23 and shaft 20 are being inserted into barrel 10 by the machine in the factory upon production, characterized in that piston supporting flange 25 has a distal circumferential rim 25A which is more clear illustrated in FIG. 8, specifically only a little bit declined forward, so as only to let the factory's mechanical force can afford to push flange 25 across primary catch 13 within barrel 10 with ease upon production, but if withdrawing plunger 20 out of barrel 10 by manual force, will be difficult, and further, gasket 30 initially before retraction is supported by gasket supporting flange 25 IA enclosing second piston flange 252, central piston flange 252A, third piston flange 253, tip supporting flange 254 and male interlocking tip 26 of plunger 20 within a long room space 35 therein, disposed with a distal central hole 33 at one end, and a proximal central hole 34 at other end, lying externally with projected proximal seal 31 at one end, middle seal 31 1 in the midst, and distal seal 32 in the proximity of distal central hole 33, but upon retraction, gasket supporting flange 25 IA will be forced enclosed within gasket 30, such that central piston flange 252A will also be forced sliding within room space 35 reaching against the distal end thereof, projecting male interlocking tip 26 out of distal central hole 33 of gasket 30 for interlocking purpose as shown on FIG.8 later. FIG. 6 is a cross-sectional view of the finished assembled syringe when preparing to use, wherein needle hub flange 41 of needle carrier 40 is screwed snugly into distal central hole 521 of luer lock 50 along threaded portion 56 in the exact manner like screwing into existing disposable luer lock syringe with same tight feeling because luer lock 50 is made of mixture with rubber and plastic, causing its hardness like plastic characteristic, and simultaneously interior of needle hub 41 A is mounted snugly onto nozzle 54 for avoiding leakage, wherein gasket 30 supported by gasket supporting flange 25 IA has been pushed until distal seal 32 reaching at base of body 15 where Occ line is marked on barrel 10 thereon. FIG. 7 is a cross-sectional view illustrating the drawing fluid manner like traditional disposable syringe does starting from the line of Occ level which is located in the proximity of body base 15 of barrel 10, withdrawing plunger 20 to draw the fluid until piston supporting flange 25 reaching at primary catch 13 as maximum, and then stop.

FIG. 8 is an enlarge partial cross-sectional view illustrating the completed injection manner when plunger 20 is pushed at the extreme end within barrel 10 abused by body base 15, gasket supporting flange 25 IA will be forced inserting enclosed within room space 35 of gasket 30, such that central piston flange 252A will consequently be forced sliding forward within room space 35 abusing at its distal end thereof, projecting male interlocking tip 26 out of distal central hole 33 of gasket 30, thereby inserting across proximal central hole 52 of luer lock 50 into female interlocking notch 53 therein, wherein inner diameter of central hole 52 is a bit smaller than outer diameter of male interlocking tip 26, yet, due to a minor elastic rubber characteristic nature specifically exists in luer lock 50 and also tip head 26A is declining towards tip 26 additionally with a gap 27 to be pressed narrower, integrated causing male interlocking tip 26 can be inserted through central hole 52 into female interlocking notch 53 comfortably. Reversely, due to major hard plastic characteristic nature specifically exists in luer lock 50 and also base of tip 26 is flat, additionally, inner base of central hole 52 is flat also, such that tip 26 is difficult to return out of central hole 52, whereby tip 26 is trapped within notch 53 accordingly.

FIG. 9 is a cross-sectional view illustrating the retraction manner after injection when plunger 20 is withdrawn, gasket supporting flange 251 A also be withdrawn abused at the proximal end within room space 35, such that luer lock 50 is remained firmly in the interlocking manner as mentioned on FIG. 8, thereby retracting luer lock 50 carrying with needle carrier 40 together into interior of barrel 10 simultaneously. Further due to dimensions of both notch 53 and central hole 52 of luer lock 50 are bigger than that of tip 26 and tip supporting flange 254 of plunger 20 respectively, which therefore cannot afford to support the weight of luer lock 50, causes luer lock 50 loosen declining at distal end, resulting needle tip 43 of needle carrier 40 to lean against the inner wall of barrel 10. Under this circumstance, if attempting to push plunger 20 forward, needle tip 43 will be abutted by interior body base 15, resulting bending and damaged at tip 43 within. FIG. 10 is a cross-sectional view illustrating the breaking manner when piston supporting flange 25 followed by piston 201 is abutted by primary catch 13 adjacent to proximal opening 12 of barrel 10 when plunger is further withdrawn, and under this situation, due to the reason as mentioned on FIG. 5, flange 25 is difficult to pull across catch 13 by manual force unless by mechanical force instead, thereby trapping piston 201 with flange 25 safely within barrel 10 for more safeguard to avoid the spent needle accidentally fallen off barrel 10 to cause needle stick injuries even though needle tip 43 is still abutted by base 15 within. Moreover, when further pulling plunger 20, fragile portion 24 will be forced to break at both fragile connectors 242 into two pieces so as to save the volume of rubbish bin when discarding besides further safeguard to prevent reusable again. While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope the appended claims.

Claims

What is claimed is:

I. A safety syringe comprising:

(a) a hollow elongated barrel means including a protruding nose with a distal opening at one end and a finger grip adjacent to a proximal opening at other end, lying internally one or a plurality of abutting structures, and one or a plurality of retaining structures located internally at one end of said protruding nose where a several female protuberances are disposed at midst in separated manner spread evenly within inner wall of said protruding nose therein.

(b) a plunger which is adapted to fit within and move axially in said barrel means, includes a push button at proximal end, a shaft connecting to a fragile portion with a piston supported by a system of flange structures including gasket supporting means extending forwardly a loosen means attached to a male interlocking structure at distal end;

(c) an adaptor made of hard but elastic rubber material comprising: a distal central hole exposing a part of a hollow nozzle with a nozzle lumen at one end which is an elongation originated from the midst within, and a proximal central hole with a supporting seal structure projected externally to avoid leakage at other end. In the proximity of said distal central hole is disposed with a several male protuberances which are in separated manner spread evenly on the external surface of said adaptor, wherein a threaded portion is located at the inner wall of said distal central hole. Internally, adjacent to said proximal opening hole is disposed with a female interlocking structure which dimension is bigger than said male interlocking structure of said plunger therein, extending forwardly a hollow passage within said nozzle opening fluid communications between said nozzle lumen of said adaptor or through the hollow needle if applied and interior chamber of said barrel means . (d) a hollow rubber element having a distal opening at one end and a proximal opening at other end connected with a room space in between internally, lying one or a plurality of seals in parallel separately and externally at the midst thereon;

(e) a hollow penetration means includes an elongated needle ended with a sharp distal tip at one end engaged with a hub extending a projected flange at other end adapted to detachably engage with said threaded portion of said adaptor enabling to penetrate into human body for injection or collecting fluid, which can be retracted into interior of said barrel means.

2. A safety syringe according to claim 1 wherein said retaining structure is to retain said adaptor within said protruding nose of said barrel means snugly and properly.

3. A safety syringe according to claim 1 wherein said female protuberances of said protruding nose matched with said male protuberances of said adaptor is to abut said adaptor to move either direction of clockwise or anticlockwise within said protruding nose when turning said needle hub.

4. A safety syringe according to claim 1 wherein said female interlocking structure comprises a loose room headed with a smaller central opening hole within said adaptor is to receive said male interlocking structure aligning said loosen means of said plunger, and retain said male interlocking structure staying loose therein, characterized in that it causes said adaptor engaged together with said hollow penetration means to stay loose within said barrel means, so that said sharp tip of said penetration means is abutted at bottom base within said barrel means.

5. A safety syringe according to claim 1 wherein one of said flange structure of said plunger is an annular flange characterized in that its circumferential rim has two different inclination degrees at the distal and proximal rims, so as to help the tip of said plunger carry said hollow rubber element inserting into said barrel means with ease upon assembling, but which is not allowed to be withdrawn out of said barrel means after assembling.

6. A safety syringe according to claim 1 wherein said gasket supporting means is an annular flange characterized in that it can support said hollow rubber element firmly at an expected position to enclose said loosen means and said male interlocking structure of said plunger within upon assembling said piston into said barrel means during production, and also it can be inserted into said room space of said hollow rubber element upon injection, thereby supporting said hollow rubber element firmly to stay at the same position when said male interlocking structure therein has been pushed forward out of said hollow rubber element for engagement purpose, so that it creates a loosen space in between said adaptor and said hollow rubber element for said adaptor in co-alignment with said hollow penetration means swinging loose within said barrel means after retraction.

7. A safety syringe according to claim 1 wherein said abutting structure is to abut said piston withdrawal out of said barrel means.

8. A safety syringe according to claim 1 wherein said fragile portion of said plunger allowed to break therein, when said piston carrying said adaptor with said penetration means is trapped by said abutting structure within said barrel means.

9. A safety syringe according to claim 4 wherein said male interlocking structure comprises an arrow-shaped tip ended with a smaller tip head and a gap in between.

10. A safety syringe according to claim 4 wherein said loosen means of said plunger is a flange smaller in diameter than said central opening hole of said adaptor.

1 1. A safety syringe comprising: a hollow, axially elongated cylindrical barrel comprises a distal opening at one end with an interior base, and a proximal opening adapted with a abutting structure therein at other end; a plunger which is adapted to fit within and move axially in said barrel, includes a push button at proximal end, a shaft connecting to a fragile structure with a piston extending forwardly a series of structures including a gasket supporting means and a loosen means attached to a male interlocking structure at distal end; a rubber element which includes a distal seal, a middle seal and a proximal seal lying externally thereon, with a distal opening at one end, and a proximal opening at other end, disposed centrally a room space in between, acts as said piston enclosing said series of structures of said plunger within, characterized in that said gasket supporting means supports said rubber element firmly upon assembling and during injection to allow said distal seal immediate close to base of said barrel for drawing up the fluid, and reversely, it also supports said rubber element firmly to allow said male interlocking structure projected out of said distal opening to perform interlocking function; an adaptor comprising: a female interlocking structure at one end, and a threaded portion is disposed centrally at other end. a hollow needle with a sharp distal tip at one end engaged by a hub extending a project flange at other end.

Said adaptor is adapted to engage at said distal opening of said barrel, and said needle is engaged detachably at said threaded portion within said adaptor snugly, and said female interlocking structure of said adaptor is adapted to receive said male interlocking structure aligning said loosen means of said plunger, characterized in that said male interlocking structure is loose staying within, and can afford to pull said adaptor with said needle into interior of said barrel upon retraction of said plunger, in the manner that said adaptor declines together with said needle causing said needle tip leans against the inner wall of said barrel and is abutted by said base within. Additionally, said piston is abused by said abutting structure provided, thereby breaking said plunger at said fragile structure provided therein upon further withdrawal of said plunger.