AU2003100984A4 - Single-Use Syringe with Self-destructive Stopper - Google Patents

Description

Our Ref:2834Inno P/00/009 Regulation 3.2

AUSTRALIA

Patents Act 1990 INNOVATION SPECIFICATION FOR AN INVENTION ENTITLED Invention title: Single-Use Syringe with Self-destructive Stopper Name of Applicant: Taiject Medical Device Co., Ltd.

Address for Service A.P.T. Patent and Trade Mark Attorneys PO Box 222 Mitcham, S.A. 5062 The invention is described in the following statement: 2 SINGLE-USE SYRINGE WITH SELF-DESTRUCTIVE STOPPER BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a hypodermic syringe and, more particularly, to a single-use syringe with self-destructive stopper.

Description of the Related Art Conventional hypodermic syringes may be collected by some people for a repeat use illegally after their service. Using a used syringe causes the patient to risk contamination. In order to prohibit people from using used syringes, single-use syringe are developed. But conventional single-use syringes are commonly complicated, expensive, and not easy to use. There are known simple designs of single-use syringes.

However, these simple designs of single-use syringes may fail easily, or not be able to completely prohibit people from a repeat use. Furthermore, conventional single-use syringes have the problem of higher residual liquid volume after their service.

Therefore, it is desirable to provide a single-use syringe that eliminates the aforesaid problems.

SUMMARY OF THE INVENTION The present invention has been accomplished under the circumstances in view. It is one object of the present invention to provide a single-use syringe with self-destructive stopper that keeps a part of the stopper maintained secured to the inside of the front neck of the barrel after the service of the syringe, preventing a repeat use of the used syringe. It is another object of the present invention to provide a single-use syringe with self-destructive stopper, which enables the stopper to expel injection liquid completely out of the barrel, reducing the amount of residual injection liquid.

To achieve these and other objects of the present invention, the single-use syringe with self-destructive stopper comprises a barrel having a hollow cylindrical body defining a 3 fluid chamber, a front neck defining a retaining chamber and terminating in a needle hub adapted to hold a needle cannula, and a shoulder connected between the hollow cylindrical body and the neck; a plunger to be moved forwards and backwards in the barrel, the plunger having a plunger body, a stopper control at a front end of the plunger body, and a thumb rest at a rear end of the plunger body; and a stopper having a first stopper body coupled to the stopper control of the plunger and adapted to seal the fluid chamber of the barrel, and a second stopper body forwardly extended from a front side of the first stopper body and adapted to seal the retaining chamber of the barrel. The second stopper body is moved with the first stopper body through the shoulder into the front neck upon forward stroke of the plunger, and broken from the first stopper body and maintained secured to the retaining chamber inside the front neck upon return stroke of the plunger.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded view of a syringe according to the present invention.

FIG. 2 is an exploded plain view of the plunger and the stopper according to the first embodiment of the present invention.

FIG. 3 is a sectional assembly view of the first embodiment of the present invention before the use of the use of the syringe.

FIG. 4 is an operational view of the first embodiment of the present invention, showing the rubber stopped moved to the shoulder of the barrel.

FIG. 5 is another operational view of the first embodiment of the present invention, showing the second stopper body stopped in the front side of the front neck of the barrel.

FIG. 6 is still another operational view of the first embodiment of the present invention, showing the plunger returned and the second stopper body remained in the front neck of the barrel.

FIG. 7 is a perspective exploded view of a syringe according to the second embodiment of the present invention.

FIG. 8 is an exploded plain view of the plunger and the stopper according to the second embodiment of the present invention.

4 FIG. 9 is a sectional assembly view of the second embodiment of the present invention before the use of the syringe.

FIG. 10 is an operational view of the second embodiment of the present invention, showing the rubber stopped moved to the shoulder of the barrel.

FIG. 11 is another operational view of the second embodiment of the present invention, showing the second stopper body stopped in the front side of the front neck of the barrel.

FIG. 12 is still another operational view of the second embodiment of the present invention, showing the plunger returned and the second stopper body remained in the front neck of the barrel.

FIG. 13 is a sectional view of the stopper according to still another alternate form of the present invention.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIGS. 1-3, a single-use syringe with self-destructive stopper in accordance with the first embodiment of the present invention is shown mounted with a needle cannula 8 and used to inject liquids into the body, comprising a barrel 10, a plunger 30, and a stopper The barrel 10 has a hollow cylindrical body 11 defining a fluid chamber 12, a front neck 14 defining a retaining chamber 15, a shoulder 13 connected between the body 11 and the neck 14, a front needle hub 16 axially forwardly extended from the neck 14 and holding the needle cannula 8, a finger flange 17 outwardly extended from one end, namely, the rear end of the body 11 remote from the shoulder 13, and an inside stop flange 18 extended around the inside wall of the body 11 near the rear open end of the fluid chamber 12. The shoulder 13 is tapered, having a diameter gradually reduced in direction from the hollow cylindrical body 11 toward the front neck The plunger 30 has a plunger body 31, a front extension rod 32 axially forwardly extended from the front end of the plunger body 31 toward the needle cannula 8, and a thumb rest 39 formed on the rear end of the plunger body 31. The diameter of the front extension rod 32 is relatively smaller than the plunger body 31. A locating tip 37 axially forwardly extended from the front end of the front extension rod 32, and three control portions, namely, the first control portion 34, the third control portion 35 and the second control portion 36 respectively extended around the periphery of the front extension rod 32. The control portions 34,35,36 form a stopper control.

The stopper 40 has a first stopper body 41 adapted to seal the fluid chamber 12, a second stopper body 42 having a conical shape formed integral with the front side of the first stopper body 41 and adapted to seal the retaining chamber 15, a receiving open chamber 43 backwardly extended in the first stopper body 41 and adapted to receive the front extension rod 32 of the plunger 30, an inside front hole 47 defined in the second stopper body 42 and forwardly extended from the receiving open chamber 43 and adapted to receive the locating tip 37 of the plunger 30, a first control portion 44 formed in the first stopper body 41 inside the receiving open chamber 43 at the rear side, a second control portion 46 formed inside the second stopper body 42 between the receiving open chamber 43 and the inside front hole 47, a third control portion formed inside the receiving open chamber 43 and spaced between the first control portion 44 and the second control portion 46, and a tearing portion 48 defined between the first stopper body 41 and the second stopper body 42. The tearing portion 48 has a diameter slightly greater than the diameter of the retaining chamber 15 of the barrel The control portions 44, 45, 46 of the stopper 40 are adapted to receive the control portions 34, 35, 36 of the plunger 30 respectively.

FIG. 3 is a sectional assembly view of the first embodiment of the present invention before the use of the syringe. When in use, as shown in FIG. 4, push the plunger forwards in the barrel 10 to force the first stopper body 41 into the shoulder 13. At this time, the plunger 30 receives a resisting force from the shoulder 13, and the user can give more push force to the plunger 30 to move the first control portion 34 and third control portion 35 of the plunger 30 forwardly away from the first control portion 44 and third control portion 45 of the stopper 40 and to force the second control portion 36 of the plunger 30 forwardly against the second control portion 46 of the stopper thereby causing the tearing portion 48 to receive stretching force from the second stopper body 42 and shearing force from the retaining chamber 15 and then to break.

When continuously pushing the plunger 30 forwards, as shown in FIG. 5, the second stopper body 42 has been separated from the first stopper body 41 and pushed by the plunger 30 and the first stopper body 41 to the front side of the retaining chamber and stopped there in position. At this time, injection liquid has been fully forced out of the fluid chamber 12 through the retaining chamber 15 and the needle cannula 8 into the patient's body.

When pulling the plunger 30 backwards from the barrel 10, the second stopper body 42 is maintained in the retaining chamber 15, and theoretically, the syringe becomes useless.

FIGS. 7-9 show another single-use syringe with self-destructive stopper constructed according to the second embodiment of the present invention. Similar to the aforesaid first embodiment of the present invention, the embodiment is also comprised of a barrel 10A, a plunger 30A, and a stopper The barrel 10A and the plunger 30A are substantially similar to the aforesaid first embodiment of the present invention with the exception of the contour of the front end of the barrel 10A. Further, the plunger 30A has a first control portion 34A and a second control portion 36A without the aforesaid third control portion According to this embodiment, the stopper 50 is comprised of a first stopper body 51 and a second stopper body 52. The first stopper body 51 has a rear receiving open chamber 53, a front retaining open chamber 54 in line and communication with the rear receiving open chamber 53, a first control portion 55 in the rear side of the rear receiving open chamber 53, and a second control portion 56 in between the rear receiving open chamber 53 and the front retaining open chamber 54. The second stopper body 52 is mounted in the front retaining open chamber 54 of the first stopper 7 body 51 and aimed at the needle cannula 8, having a control portion 57 in the rear side, a front retaining flange 58 extended around the periphery near the front side, and a rear retaining flange 59 extended around the periphery at the rear side. The second stopper body 52 has a conical front end, and is press-fitted into the front retaining open chamber 54 of the first stopper body 51 to prevent a leakage.

The operation of the second embodiment is outlined hereinafter. As illustrated in FIG.

9, when pushing the plunger 30A in the barrel 10A toward the needle cannula 8, the first stopper body 51 and the second stopper body 52 are moved with the plunger forwards relative to the barrel 10A. When the first stopper body 51 reached the shoulder of the barrel 10A as shown in FIG. 10, the stopper 50 receives a resisting forced from the peripheral wall of the shoulder of the barrel 10A. When increasing the push force at this time, the second control portion 36A of the plunger 30A will be forced to move the second stopper body 52 into the retaining chamber of the barrel 10A and stopped there in position as shown in FIG. 11. When pulling the plunger backwards after injection, the second stopper body 52 remains in the front neck of the barrel 10A, as shown in FIG. 12.

Referring to FIG. 13, the second stopper body of the stopper can be made having a forwardly extended front extension portion 49B that can minimizes the amount of residual injection fluid in the barrel after injection.

As indicated above, a single-use syringe with self-destructive stopper made according to the present invention has the following features: 1. The design and matching of the plunger and the stopper enable the injection fluid to be fully forced out of the barrel, reducing the amount of residual injection fluid in the barrel after injection.

2. A part of the stopper is maintained in the front neck of the barrel after injection, prohibiting a reuse of the used syringe.

3. The simple assembly and separation arrangement between the stopper and the plunger facilitates the operation of the syringe.

Claims (4)

1. A single-use syringe with self-destructive stopper comprising: a barrel having a hollow cylindrical body defining a fluid chamber, a front neck defining a retaining chamber and terminating in a needle hub adapted to hold a needle cannula, and a shoulder connected between said hollow cylindrical body and said neck; a plunger to be moved forwards and backwards in said barrel, said plunger having a plunger body, a stopper control at a front end of said plunger body, and a thumb rest at a rear end of said plunger body; and a stopper having a first stopper body coupled to said stopper control of said plunger and adapted to seal the fluid chamber of said barrel, and a second stopper body forwardly extended from a front side of said first stopper body and adapted to seal the retaining chamber of said barrel; wherein said second stopper body is moved with said first stopper body through said shoulder into said front neck upon forward stroke of said plunger, and broken from said first stopper body and maintained secured to said retaining chamber inside said front neck upon return stroke of said plunger.

2. The syringe as claimed in claim 1, wherein said plunger has a front extension rod, and said stopper control is formed on said front extension rod.

3. The syringe as claimed in claim 1, wherein said stopper further has a tearing portion formed integral with a front part of said first stopper body and a rear part of said second stopper body.

4. The syringe as claimed in claim 1, wherein said second stopper body is press-fitted into a front open chamber in said first stopper body. 9 The syringe as claimed in claim 1, wherein said stopper has a receiving open chamber and a first control portion formed in said first stopper body, and a second control portion formed in said second stopper body. Dated this 1st day of December 2003 TAIJECT MEDICAL DEVICE CO., LTD. By their Patent Attorneys A.P.T. Patent and Trade Mark Attorneys