Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1999-12-22
2001-06-26
Kennedy, Sharon (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
Reexamination Certificate
active
06251095
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a safety syringe in which the injection needle can be pulled back into the syringe barrel after injection.
2. Description of the Prior Art
Various types of disposable syringes are widely used nowadays. After discarded, large amount of such syringes result in problem of pollution of environment. The used syringes often impale medical personnel and infect the personnel with viruses or bacteria carried by the patients. Especially, in case the medical personnel are infected with AIDS virus, the personnel may die innocently.
In order to solve these problems, various types of retractable syringes have been developed. For example, a spring is installed between the syringe barrel and the piston for pulling the needle back into the barrel after injection. However, due to the property of the liquid medicine, the material of the spring is strictly limited. Therefore, the structure of such syringe is complicated and the manufacturing cost is very high.
Various types of safety syringes free from the springs have been also developed. In such syringe, a latch member is disposed at the bottom of the barrel, whereby when the plunger is pushed to the bottom of the barrel, the latch member latches the plunger with the needle. Therefore, when the plunger is pulled back, the needle is retracted into the barrel along with the plunger so as to avoid impalement of the medical personnel or other persons.
In order to avoid leakage of the liquid medicine and unexpected dropping of the needle from the barrel, the needle must be firmly assembled with the barrel. However, in the case that the needle is excessively firmly assembled with the barrel, it will be difficult to pull the needle back into the barrel. Therefore, it is troublesome to consider both situations.
In the applicant's U.S. Pat. No. 5,899,887, a replaceable needle structure is provided. Therefore, the manufacturers are unnecessary to manufacture and prepare safety syringes with many different kinds of needles.
SUMMARY OF THE INVENTION
In order to solve the above problems, it is a primary object of the present invention to provide a safety syringe with retractable standard needle employing a standard needle holder which can be more firmly mounted on the syringe barrel.
It is a further object of the present invention to provide a safety syringe with retractable standard needle which has simplified structure and can be more easily manufactured and used. The structure prevents two sets of needle pulling members from being latched with each other accidentally.
It is still a further object of the present invention to provide a safety syringe with retractable standard needle in which the plunger can be easily aligned with the injection needle and easily and firmly latched with the injection needle so that the injection needle can be reliably pulled into the syringe barrel.
According to the above objects, the safety syringe with retractable standard needle of the present invention includes: a syringe barrel having a first end, a second end and a first axis, near the first end of the syringe barrel being disposed a needle socket, near the second end of the syringe barrel being disposed a barrel section, the barrel section being formed with an internal chamber surrounding the first axis, the needle socket having a needle holder cavity surrounding the first axis, an annular shoulder section being formed between the internal chamber and the needle holder cavity, the internal chamber having a first end and a second end, the second end of the internal chamber being formed with a first opening coinciding with the second end of the syringe barrel, the first end of the internal chamber communicating with the needle holder cavity, the outer circumference of the first opening being formed with an annular stopper section, the inner wall of the first end of the internal chamber being formed with at least one entrance recess axially extending along the internal chamber, the first end of the syringe barrel being formed with a second opening cutting off the annular stopper section to form stopper edge, the distance between the edge of the second opening and the first axis being defined as a first width; a plunger having a first end and a second end, the first end being disposed with a piston and is rotatably fitted in the syringe barrel, the plunger having a second axis, the second end of the plunger having at least one stopper section, the distance between the outer edge of the stopper section and the second axis of the plunger being defined as a second width, the second width being larger than the radius of the internal chamber but smaller than the first width, whereby the stopper section of the plunger is stopped by the stopper edge of the syringe barrel and thus the piston of the first end of the plunger cannot touch the annular shoulder section between the internal chamber and the needle holder cavity, when the plunger is rotated to align the stopper section thereof with the second opening of the first end of the syringe barrel, the stopper section of the plunger being slided from the second opening into the entrance recess of the internal chamber, at this time, the piston at the first end of the plunger being permitted to touch the annular shoulder section between the internal chamber and the needle holder cavity; a first needle holder having a first end and a second end, the second end having a fitting section; an injection needle inserted in the first end of the first needle holder; a second needle holder having a first end, a second end, a second fitting section and a plug section, the second fitting section being formed at the first end and being detachably fitted with the first fitting section of the first needle holder, the plug section being formed at the second end and being fitted in the needle holder cavity of the needle socket of the syringe barrel, the second needle holder having a third axis and being formed with a through hole passing through the third axis for guiding the liquid to flow from the syringe barrel through the through hole to the injection needle or from the injection needle through the through hole to the syringe barrel; and a needle pulling mechanism including: a first needle pulling member having a first end and a second end, the first end being connected with one of the first end of the plunger and the second end of the second needle holder, the first needle pulling member having at least one click, each click having a first end and a second end, the first end being resiliently movably connected with the second end of the first needle pulling member, the distance between the first end of the click and either of the second axis and the first axis being defined as a first distance, the second end of the click extending toward the second end of the first needle pulling member, in a free state, the distance between the second end of the click and either of the second axis and the first axis being defined as a second distance, the second distance being smaller than the first distance, the distance between the second end of the click and the first end of the first needle pulling member being defined as a third distance, the distance between the first end of the click and the first end of the first needle pulling member being defined as a fourth distance, the third distance being smaller than the fourth distance, whereby the click serves as a reverse thorn; and a second needle pulling member having a first end and a second end, the first end being connected with other of the first end of the plunger and the second end of the second needle holder, the first end of the second needle pulling member being formed as a neck stem, the second end of the second needle pulling member being formed as a detent having a hook section, the hook section having a radially extending hook face, when the first end of the plunger being pushed to the first end of the syringe barrel, the hook section of the detent stretching open and slides over the second end of the
Kennedy Sharon
Rosenberg , Klein & Lee
Serke Catherine
LandOfFree
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