Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Patent
1991-05-08
1993-07-13
Rosenbaum, C. Fred
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
604110, 604171, 604196, 604197, A61M 532
Patent
active
052268934
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to a hypodermic syringe, and in particular to a hypodermic syringe having a retractable needle. This invention is applicable for medical and veterinary applications, and it will be convenient to hereinafter describe the invention in relation to that exemplary application. However, it is to be appreciated that the invention is not limited to those applications.
DESCRIPTION OF THE RELATED ART
Following the international concern on the spread of the A.I.D.S. virus, it is now realised that one major form of transmission of this virus is through contact with or use of syringes that have been infected with the A.I.D.S. virus.
In conventional hypodermic syringes, the needle remains exposed after use of that syringe. There is therefore the possibility of being accidentally pricked by the needle after the syringe has been used. This may result in infection with the A.I.D.S. virus if the patient is a carrier of that virus. Furthermore, the disposal of used syringes can be a hazardous procedure because of the exposed needles and the possibility that any one of the syringes may be infected.
Another disadvantage of conventional hypodermic syringes is that the syringe can be readily re-used. In the case of intravenous drug users, a single syringe is often shared by a number of people. This greatly increases the possibility of contracting the A.I.D.S. virus. If one of the persons is a carrier of the virus and infects the syringe, this syringe will infect the others with the virus.
Syringes have been developed where the needle can be retracted after the syringe has been used. Examples of such syringes are disclosed in Australian Patent Application Nos. 13088/88, 14189/88 and 16234/88. These prior syringes are generally arranged in the same way as conventional syringes with a hollow needle extending from one end of a cylindrical housing and a plunger assembly extending from the other end of the housing for displacing a piston supported therein. Means may be provided on the piston to engage an end of the needle at the end of the injection stroke. The needle can then be withdrawn by pulling the piston back through the housing. Alternatively, the needle is supported on means which allow the needle to be withdrawn after the injection stroke.
In these prior arrangements, the needle remains exposed at the end of the injection until the retracting means are actuated. There is therefore still a possibility of accidental contact with the needle immediately after the syringe has been used. Also, because the plunger assembly must be pulled back after the injection or the needle support must be actuated to retract the needle, the user may neglect to or have insufficient time to retract the needle so that it remains exposed after syringe use thereby negating the benefit of the retracting means.
It is therefore an object of the present invention to provide a hypodermic syringe having a hypodermic needle which can be retracted during the injection stroke of the syringe to minimise the possibility of accidental contact with the needle.
It is also a preferred object of the present invention to provide a single use hypodermic syringe which cannot be or is difficult to re-use.
SUMMARY OF THE INVENTION
With this in mind, the present invention provides a hypodermic syringe for the injection of an inoculant liquid including a housing, a plunger assembly slidably supported by the housing, and a hollow needle which can be fully accommodated within and be extendible from the housing wherein the needle is supported by the plunger assembly and retracts into the housing during an injection stroke of the syringe.
As the needle retracts into the housing during the injection stroke, there is no need for a further actuation of the syringe to retract the needle.
The hypodermic syringe preferably further includes safety means for trapping the needle within the housing after the completion of the injection stroke. The plunger assembly preferably includes an elongate stem having a piston at one end thereof
REFERENCES:
patent: 3066671 (1962-12-01), Cohen
patent: 3587575 (1971-06-01), Lichtenstein
patent: 4909793 (1990-03-01), Vining et al.
patent: 4917669 (1990-04-01), Bonaldo
patent: 4936830 (1990-06-01), Verlin
patent: 4938745 (1990-07-01), Sagstetter
patent: 4950252 (1990-08-01), Luther et al.
Linguiti Frank M.
Murray William H.
Rosenbaum C. Fred
Stright Jr. Ronald K.
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