Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1998-09-01
2001-06-19
Kennedy, Sharon (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S200000, C604S232000, C604S110000
Reexamination Certificate
active
06248094
ABSTRACT:
BACKGROUND AND FIELD OF THE INVENTION
This invention relates to hypodermic syringes and more particularly relates to a novel and improved syringe having a retractable needle assembly to prevent cross-contamination or other accidental injury when delivering an injectable solution to a patient.
Various types of syringes have been devised with a retractable needle assembly, for example, to prevent reuse or improve the safety features of the syringe. Representative devices are those illustrated and disclosed in U.S. Pat. No. 3,890,971 to T. A. Leeson et al, U.S. Pat. No. 4,675,005 to J. DeLuccia and U.S. Pat. No. 4,781,684 to L. E. Trenner. However, each of these references describe a single-use, disposable syringe having a unique fluid containment system which complements the respective retractable needle assembly. Thus, it is highly desirable to provide a retractable needle assembly for use in non-disposable syringes of the type which employ pre-filled, disposable carpules for containing the medical solution.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide for a novel and improved type of syringe which employs a retractable needle in combination with carpules for containing the injectable solution.
It is another object of the present invention to provide for a novel and improved syringe which prevents accidental injury to those operating the syringe by retracting the used needle within the expendable carpule following the injection.
It is a further object of the present invention to provide for a novel and improved method of operating a retractable needle syringe in a manner which prevents injury to an operator.
It is another object of the present invention to provide the functionality of the retractable needle with syringes and carpules that are familiar to the operator.
It is a further object of the present invention to utilize a retractable needle assembly with a standard dental syringe, although other applications will become readily apparent.
In accordance with the present invention, an improved syringe has been devised in which a carpule is fitted within a hollow interior portion of a cylindrical housing. The carpule preferably includes first and second open ends and a needle-retaining member and a fluid-expelling member disposed within the respective open ends to define a fluid chamber therebetween. The carpule is fitted within the cylindrical housing so that the needle-retaining member is positioned adjacent a front end of the housing, thereby allowing one end of a needle to be inserted through the needle-retaining member and into the fluid chamber of the carpule while the opposite end of the needle projects from the front end of the housing for injecting a patient. A plunger is connected to the fluid-expelling member through a rear end of the housing to push the fluid-expelling member forward and force substantially all the fluid within the fluid chamber through the needle. The plunger includes a penetrating end which securely engages the fluid-expelling member and allows the fluid-expelling member to be retracted toward the rear end of the syringe.
In a preferred embodiment, an attachment means is fixed to a front surface of the fluid-expelling member to securely engage a rear surface of the needle-retaining member as the last of the fluid is expelled from the fluid chamber and the fluid-expelling member contacts the needle-retaining member. The plunger is then retracted to pull the needle-retaining member along with the fluid-expelling member toward the second end of the carpule. The needle remains frictionally engaged by the needle-retaining member and is thus retracted within the carpule together with the fluid-expelling member and the needle-retaining member. The carpule may then be removed from the syringe housing and disposed of together with the used needle without requiring the operator to handle or even touch the needle.
In another embodiment, the needle-retaining member includes a receptacle defined in the rear surface to receive the end of the needle inserted through the needle-retaining member. The end of the needle does not extend beyond the rear surface of the needle-retaining member, and the receptacle is in fluid communication with the fluid chamber of the carpule so that any fluid within the fluid chamber must flow into the receptacle before passing through the needle. The receptacle thus serves to enhance the contact between the fluid-expelling member and the needle-retaining member while also ensuring that substantially all of the fluid within the fluid chamber drains into the receptacle where it is then expelled through the needle.
REFERENCES:
patent: 3890971 (1975-06-01), Leeson et al.
patent: 4675005 (1987-06-01), DeLuccia
patent: 4781684 (1988-11-01), Trenner
patent: 5098390 (1992-03-01), Wallingford
patent: 5116319 (1992-05-01), ven den Haak
patent: 5205824 (1993-04-01), Mazur
patent: 5575774 (1996-11-01), Chen
patent: 5785687 (1998-07-01), Saito
Kennedy Sharon
Reilly John E.
Thissell Jeremy
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